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Wang JY, Song QL, Wang YL, Jiang ZM. Urinary oxygen tension and its role in predicting acute kidney injury: A narrative review. J Clin Anesth 2024; 93:111359. [PMID: 38061226 DOI: 10.1016/j.jclinane.2023.111359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/12/2023] [Accepted: 12/01/2023] [Indexed: 01/14/2024]
Abstract
Acute kidney injury occurs frequently in the perioperative setting. The renal medulla often endures hypoxia or hypoperfusion and is susceptible to the imbalance between oxygen supply and demand due to the nature of renal blood flow distribution and metabolic rate in the kidney. The current available evidence demonstrated that the urine oxygen pressure is proportional to the variations of renal medullary tissue oxygen pressure. Thus, urine oxygenation can be a candidate for reflecting the change of oxygen in the renal medulla. In this review, we discuss the basic physiology of acute kidney injury, as well as techniques for monitoring urine oxygen tension, confounding factors affecting the reliable measurement of urine oxygen tension, and its clinical use, highlighting its potential role in early detection and prevention of acute kidney injury.
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Affiliation(s)
- Jing-Yan Wang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Qi-Liang Song
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Yu-Long Wang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China
| | - Zong-Ming Jiang
- Department of Anesthesia, Shaoxing People's Hospital, Shaoxing 312000, Zhejiang Province, China.
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2
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Dong C, Zhou J, Su X, He Z, Song Q, Song C, Ke H, Wang C, Liao W, Yang S. Understanding formation processes of calcareous nephrolithiasis in renal interstitium and tubule lumen. J Cell Mol Med 2024; 28:e18235. [PMID: 38509735 PMCID: PMC10955165 DOI: 10.1111/jcmm.18235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 02/07/2024] [Accepted: 02/28/2024] [Indexed: 03/22/2024] Open
Abstract
Kidney stone, one of the oldest known diseases, has plagued humans for centuries, consistently imposing a heavy burden on patients and healthcare systems worldwide due to their high incidence and recurrence rates. Advancements in endoscopy, imaging, genetics, molecular biology and bioinformatics have led to a deeper and more comprehensive understanding of the mechanism behind nephrolithiasis. Kidney stone formation is a complex, multi-step and long-term process involving the transformation of stone-forming salts from free ions into asymptomatic or symptomatic stones influenced by physical, chemical and biological factors. Among the various types of kidney stones observed in clinical practice, calcareous nephrolithiasis is currently the most common and exhibits the most intricate formation mechanism. Extensive research suggests that calcareous nephrolithiasis primarily originates from interstitial subepithelial calcified plaques and/or calcified blockages in the openings of collecting ducts. These calcified plaques and blockages eventually come into contact with urine in the renal pelvis, serving as a nidus for crystal formation and subsequent stone growth. Both pathways of stone formation share similar mechanisms, such as the drive of abnormal urine composition, involvement of oxidative stress and inflammation, and an imbalance of stone inhibitors and promoters. However, they also possess unique characteristics. Hence, this review aims to provide detailed description and present recent discoveries regarding the formation processes of calcareous nephrolithiasis from two distinct birthplaces: renal interstitium and tubule lumen.
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Affiliation(s)
- Caitao Dong
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Jiawei Zhou
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Xiaozhe Su
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Ziqi He
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Qianlin Song
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Chao Song
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Hu Ke
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Chuan Wang
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Wenbiao Liao
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
| | - Sixing Yang
- Department of UrologyRenmin Hospital of Wuhan UniversityWuhanHubei ProvinceChina
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3
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Hodgin JB, Smith C, Kretzler M. Multi-omics data integration shines a light on the renal medulla. Kidney Int 2024; 105:242-244. [PMID: 38245213 DOI: 10.1016/j.kint.2023.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 01/22/2024]
Abstract
The renal medulla maintains salt and water balance and is prone to dysregulation because of high oxygen demand. Challenges in obtaining high-quality tissue have limited characterization of molecular programs regulating the medulla. Haug et al. leveraged gene expression, chromatin accessibility, long-range chromosomal interactions, and spatial transcriptomics to build a reference set of medullary tissue marker genes to define the medullary role in kidney function, exemplifying the strength and utility of multi-omic data integration.
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Affiliation(s)
- Jeffrey B Hodgin
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, USA.
| | - Cathy Smith
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Matthias Kretzler
- Division of Nephrology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA; Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, USA
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4
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Layton AT. A comparative modeling study of the mitochondrial function of the proximal tubule and thick ascending limb cells in the rat kidney. Am J Physiol Renal Physiol 2024; 326:F189-F201. [PMID: 37994410 DOI: 10.1152/ajprenal.00290.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/09/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023] Open
Abstract
To reabsorb >99% of the glomerular filtrate, the metabolic demand of the kidney is high. Interestingly, renal blood flow distribution exhibits marked inhomogeneity, with typical tissue oxygen tension (Po2) of 50-60 mmHg in the well-perfused cortex and 10-20 mmHg in the inner medulla. Cellular fluid composition and acidity also varies substantially. To understand how different renal epithelial cells adapt to their local environment, we have developed and applied computational models of mitochondrial function of proximal convoluted tubule cell (baseline Po2 = 50 mmHg, cytoplasmic pH = 7.20) and medullary thick ascending limb (mTAL) cell (baseline Po2 = 10 mmHg, cytoplasmic pH = 6.85). The models predict key cellular quantities, including ATP generation, P/O (phosphate/oxygen) ratio, proton motive force, electrical potential gradient, oxygen consumption, the redox state of key electron carriers, and ATP consumption. Model simulations predict that close to their respective baseline conditions, the proximal tubule and mTAL mitochondria exhibit qualitatively similar behaviors. Nonetheless, because the mTAL mitochondrion has adapted to a much lower Po2, it can sustain a sufficiently high ATP production at Po2 as low as 4-5 mmHg, whereas the proximal tubule mitochondria would not. Also, because the mTAL cytosol is already acidic under baseline conditions, the proton motive force (pmf) exhibits higher sensitivity to further acidification. Among the different pathways that lead to oxidative phosphorylation impairment, the models predict that both the proximal tubule and mTAL mitochondria are most sensitive to reductions in Complex III activity.NEW & NOTEWORTHY Tissue fluid composition varies substantially within the mammalian kidney. The renal cortex is well perfused and pH neutral, whereas some medullary regions are hypoxic and acidic. How do these environments affect the mitochondrial function of proximal convoluted tubule and medullary thick ascending limb cells, which reside in the cortex and medulla, respectively? This computational modeling study demonstrates that these mitochondria can adapt to their contrasting environments and exhibit different sensitivities to perturbations to local environments.
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Affiliation(s)
- Anita T Layton
- Department of Applied Mathematics, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
- Department of Biology, Cheriton School of Computer Science, and School of Pharmacology, University of Waterloo, Waterloo, Ontario, Canada
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5
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Canela VH, Bowen WS, Ferreira RM, Syed F, Lingeman JE, Sabo AR, Barwinska D, Winfree S, Lake BB, Cheng YH, Gaut JP, Ferkowicz M, LaFavers KA, Zhang K, Coe FL, Worcester E, Jain S, Eadon MT, Williams JC, El-Achkar TM. A spatially anchored transcriptomic atlas of the human kidney papilla identifies significant immune injury in patients with stone disease. Nat Commun 2023; 14:4140. [PMID: 37468493 PMCID: PMC10356953 DOI: 10.1038/s41467-023-38975-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 05/24/2023] [Indexed: 07/21/2023] Open
Abstract
Kidney stone disease causes significant morbidity and increases health care utilization. In this work, we decipher the cellular and molecular niche of the human renal papilla in patients with calcium oxalate (CaOx) stone disease and healthy subjects. In addition to identifying cell types important in papillary physiology, we characterize collecting duct cell subtypes and an undifferentiated epithelial cell type that was more prevalent in stone patients. Despite the focal nature of mineral deposition in nephrolithiasis, we uncover a global injury signature characterized by immune activation, oxidative stress and extracellular matrix remodeling. We also identify the association of MMP7 and MMP9 expression with stone disease and mineral deposition, respectively. MMP7 and MMP9 are significantly increased in the urine of patients with CaOx stone disease, and their levels correlate with disease activity. Our results define the spatial molecular landscape and specific pathways contributing to stone-mediated injury in the human papilla and identify associated urinary biomarkers.
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Affiliation(s)
- Victor Hugo Canela
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - William S Bowen
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Ricardo Melo Ferreira
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Farooq Syed
- Center for Diabetes and Metabolic Diseases, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - James E Lingeman
- Department of Urology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Angela R Sabo
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Daria Barwinska
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Seth Winfree
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Blue B Lake
- San Diego Institute of Science, Altos Labs, San Diego, CA, USA
| | - Ying-Hua Cheng
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Joseph P Gaut
- Department of Pathology and Immunology, Washington University, St. Louis, MO, USA
| | - Michael Ferkowicz
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kaice A LaFavers
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kun Zhang
- San Diego Institute of Science, Altos Labs, San Diego, CA, USA
| | - Fredric L Coe
- Department of Medicine, Division of Nephrology, University of Chicago, Chicago, IL, USA
| | - Elaine Worcester
- Department of Medicine, Division of Nephrology, University of Chicago, Chicago, IL, USA
| | - Sanjay Jain
- Department of Medicine, Division of Nephrology, Washington University, St. Louis, MO, USA.
| | - Michael T Eadon
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - James C Williams
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Tarek M El-Achkar
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Medicine, Indianapolis VA Medical Center, Indianapolis, IN, USA.
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6
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Du C, Xu H, Cao C, Cao J, Zhang Y, Zhang C, Qiao R, Ming W, Li Y, Ren H, Cui X, Luan Z, Guan Y, Zhang X. Neutral amino acid transporter SLC38A2 protects renal medulla from hyperosmolarity-induced ferroptosis. eLife 2023; 12:80647. [PMID: 36722887 PMCID: PMC9949798 DOI: 10.7554/elife.80647] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/31/2023] [Indexed: 02/02/2023] Open
Abstract
Hyperosmolarity of the renal medulla is essential for urine concentration and water homeostasis. However, how renal medullary collecting duct (MCD) cells survive and function under harsh hyperosmotic stress remains unclear. Using RNA-Seq, we identified SLC38A2 as a novel osmoresponsive neutral amino acid transporter in MCD cells. Hyperosmotic stress-induced cell death in MCD cells occurred mainly via ferroptosis, and it was significantly attenuated by SLC38A2 overexpression but worsened by Slc38a2-gene deletion or silencing. Mechanistic studies revealed that the osmoprotective effect of SLC38A2 is dependent on the activation of mTORC1. Moreover, an in vivo study demonstrated that Slc38a2-knockout mice exhibited significantly increased medullary ferroptosis following water restriction. Collectively, these findings reveal that Slc38a2 is an important osmoresponsive gene in the renal medulla and provide novel insights into the critical role of SLC38A2 in protecting MCD cells from hyperosmolarity-induced ferroptosis via the mTORC1 signalling pathway.
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Affiliation(s)
- Chunxiu Du
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical UniversityDalianChina
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic DiseasesDalianChina
- Health Science Center, East China Normal UniversityShanghaiChina
| | - Hu Xu
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Cong Cao
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Jiahui Cao
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Yufei Zhang
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Cong Zhang
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Rongfang Qiao
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Wenhua Ming
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Yaqing Li
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Huiwen Ren
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Xiaohui Cui
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Zhilin Luan
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
| | - Youfei Guan
- Advanced Institute for Medical Sciences, Dalian Medical UniversityDalianChina
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Dalian Medical UniversityDalianChina
- Dalian Key Laboratory for Nuclear Receptors in Major Metabolic DiseasesDalianChina
| | - Xiaoyan Zhang
- Health Science Center, East China Normal UniversityShanghaiChina
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7
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Mutchler SM, Shi S, Whelan SCM, Kleyman TR. Validation of commercially available antibodies directed against subunits of the epithelial Na + channel. Physiol Rep 2023; 11:e15554. [PMID: 36636010 PMCID: PMC9837423 DOI: 10.14814/phy2.15554] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 01/14/2023] Open
Abstract
The epithelial Na+ channel (ENaC) is traditionally composed of three subunits, although non-canonical expression has been found in various tissues including the vasculature, brain, lung, and dendritic cells of the immune system. Studies of ENaC structure and function have largely relied on heterologous expression systems, often with epitope-tagged channel subunits. Relevant in vivo physiological studies have used ENaC inhibitors, mice with global or tissue specific knockout of subunits, and anti-ENaC subunit antibodies generated by investigators or by commercial sources. Availability of well-characterized, specific antibodies is imperative as we move forward in understanding the role of ENaC in non-epithelial tissues where expression, subunit organization, and electrophysiological characteristics may differ from epithelial tissues. We report that a commonly used commercial anti-α subunit antibody recognizes an intense non-specific band on mouse whole kidney and lung immunoblots, which migrates adjacent to a less intense, aldosterone-induced full length α-subunit. This antibody localizes to the basolateral membrane of aquaporin 2 negative cells in kidney medulla. We validated antibodies against the β- and γ-subunits from the same commercial source. Our work illustrates the importance of validation studies when using popular, commercially available anti-ENaC antibodies.
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Affiliation(s)
| | - Shujie Shi
- Department of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | | | - Thomas R. Kleyman
- Department of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
- Department of Cell BiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
- Department of Pharmacology and Chemical BiologyUniversity of PittsburghPittsburghPennsylvaniaUSA
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8
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Izmailova O, Kabaliei A, Shynkevych V, Shlykova O, Kaidashev I. PPARG agonist pioglitazone influences diurnal kidney medulla mRNA expression of core clock, inflammation-, and metabolism-related genes disrupted by reverse feeding in mice. Physiol Rep 2022; 10:e15535. [PMID: 36511486 PMCID: PMC9746034 DOI: 10.14814/phy2.15535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023] Open
Abstract
This study examined the influence of PPARG activation by pioglitazone (PG) on the mRNA of core clock, inflammation- and metabolism-related genes in the mouse kidney medulla as well as urinary sodium/potassium excretion rhythms disrupted by reverse feeding. Mice were assigned to daytime feeding and nighttime feeding groups. PG 20 mg/kg was administered at 7 am or 7 pm. On day 8 of the feeding intervention, mice were killed at noon and midnight. Kidney medulla expression of Arntl, Clock, Nr1d1, Cry1, Cry2, Per1, Per2, Nfe2l2, Pparg, and Scnn1g was determined by qRT PCR. We measured urinary K+ , Na+ , urine volume, food, and H2 O intake. The reverse feeding uncoupled the peripheral clock gene rhythm in mouse kidney tissues. It was accompanied by a decreased expression of Nfe2l2 and Pparg as well as an increased expression of Rela and Scnn1g. These changes in gene expressions concurred with an increase in urinary Na+ , K+ , water excretion, microcirculation disorders, and cell loss, especially in distal tubules. PG induced the restoration of diurnal core clock gene expression as well as Nfe2l2, Pparg, Scnn1g mRNA, and decreased Rela expressions, stimulating Na+ reabsorption and inhibiting K+ excretion. PG intake at 7 pm was more effective than at 7 am.
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9
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Zhu Z, Ruan S, Jiang Y, Huang F, Xia W, Chen J, Cui Y, He C, Zeng F, Li Y, Chen Z, Chen H. α-Klotho released from HK-2 cells inhibits osteogenic differentiation of renal interstitial fibroblasts by inactivating the Wnt-β-catenin pathway. Cell Mol Life Sci 2021; 78:7831-7849. [PMID: 34724098 DOI: 10.1007/s00018-021-03972-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 08/18/2021] [Accepted: 09/06/2021] [Indexed: 01/01/2023]
Abstract
Randall's plaques (RP) are well established as precursor lesions of idiopathic calcium oxalate (CaOx) stones, and the process of biomineralization driven by osteogenic-like cells has been highlighted in RP formation, but the mechanism is poorly understood. Given the inhibitory role of α-Klotho (KL), an aging suppressor protein with high expression in kidneys, in ectopic calcification and the close association between KL gene polymorphisms and urolithiasis susceptibility, we determined the potential role of KL in RP formation. This study found that both soluble KL (s-KL) and transmembrane KL (m-KL) were downregulated, and that s-KL but not m-KL was inversely correlated with upregulation of osteogenic markers in RP tissues. Additionally, s-KL expression was markedly suppressed in human renal interstitial fibroblasts (hRIFs) and slightly suppressed in HK-2 cells after osteogenic induction, intriguingly, which was echoed to the greater osteogenic capability of hRIFs than HK-2 cells. Further investigations showed the inhibitory effect of s-KL on hRIF osteogenic differentiation in vitro and in vivo. Moreover, coculture with recombinant human KL (r-KL) or HK-2 cells suppressed osteogenic differentiation of hRIFs, and this effect was abolished by coculture with KL-silenced HK-2 cells or the β-catenin agonist SKL2001. Mechanistically, s-KL inactivated the Wnt-β-catenin pathway by directly binding to Wnt2 and upregulating SFRP1. Further investigations identified activation of the Wnt-β-catenin pathway and downregulation of SFRP1 and DKK1 in RP tissues. In summary, this study identified s-KL deficiency as a pathological feature of RP and revealed that s-KL released from HK-2 cells inhibited osteogenic differentiation of hRIFs by inactivating the Wnt-β-catenin pathway, not only providing in-depth insight into the role of s-KL in renal interstitial biomineralization but also shedding new light on the interaction of renal tubular epithelial cells with interstitial cells to clarify RP formation.
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Affiliation(s)
- Zewu Zhu
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Shuhao Ruan
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yingcheng Jiang
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Fang Huang
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Weiping Xia
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Jinbo Chen
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yu Cui
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Cheng He
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Feng Zeng
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Yang Li
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Zhiyong Chen
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
| | - Hequn Chen
- Department of Urology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
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10
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Lozić M, Filipović N, Jurić M, Kosović I, Benzon B, Šolić I, Kelam N, Racetin A, Watanabe K, Katsuyama Y, Ogata M, Saraga-Babić M, Vukojević K. Alteration of Cx37, Cx40, Cx43, Cx45, Panx1, and Renin Expression Patterns in Postnatal Kidneys of Dab1-/- ( yotari) Mice. Int J Mol Sci 2021; 22:1284. [PMID: 33525532 PMCID: PMC7865779 DOI: 10.3390/ijms22031284] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/24/2021] [Accepted: 01/25/2021] [Indexed: 12/23/2022] Open
Abstract
Numerous evidence corroborates roles of gap junctions/hemichannels in proper kidney development. We analyzed how Dab1 gene functional silencing influences expression and localization of Cx37, Cx40, Cx43, Cx45, Panx1 and renin in postnatal kidneys of yotari mice, by using immunohistochemistry and electron microscopy. Dab1 Δ102/221 might lead to the activation of c-Src tyrosine kinase, causing the upregulation of Cx43 in the medulla of yotari mice. The expression of renin was more prominent in yotari mice (p < 0.001). Renin granules were unusually present inside the vascular walls of glomeruli capillaries, in proximal and distal convoluted tubules and in the medulla. Disfunction of Cx40 is likely responsible for increased atypically positioned renin cells which release renin in an uncontrolled fashion, but this doesn't rule out simultaneous involvement of other Cxs, such as Cx45 which was significantly increased in the yotari cortex. The decreased Cx37 expression in yotari medulla might contribute to hypertension reduction provoked by high renin expression. These findings imply the relevance of Cxs/Panx1 as markers of impaired kidney function (high renin) in yotari mice and that they have a role in the preservation of intercellular signaling and implicate connexopathies as the cause of premature death of yotari mice.
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Affiliation(s)
- Mirela Lozić
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Natalija Filipović
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Marija Jurić
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Ivona Kosović
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Benjamin Benzon
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Ivana Šolić
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Nela Kelam
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Anita Racetin
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
- Department of Medical Genetics, School of Medicine, University of Mostar, 88000 Mostar, Bosnia and Herzegovina
| | - Koichiro Watanabe
- Department of Anatomy, Shiga University of Medical Science, Ötsu 520-2192, Japan; (K.W.); (Y.K.)
| | - Yu Katsuyama
- Department of Anatomy, Shiga University of Medical Science, Ötsu 520-2192, Japan; (K.W.); (Y.K.)
| | - Masaki Ogata
- Division of Anatomy, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, 981-Miyagi 8558, Japan;
| | - Mirna Saraga-Babić
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
| | - Katarina Vukojević
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, 21000 Split, Croatia; (M.L.); (N.F.); (M.J.); (I.K.); (B.B.); (I.Š.); (N.K.); (A.R.); (M.S.-B.)
- Department of Medical Genetics, School of Medicine, University of Mostar, 88000 Mostar, Bosnia and Herzegovina
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11
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Xu Y, Hu J, Yilmaz DE, Bachmann S. Connexin43 is differentially distributed within renal vasculature and mediates profibrotic differentiation in medullary fibroblasts. Am J Physiol Renal Physiol 2021; 320:F17-F30. [PMID: 33196322 DOI: 10.1152/ajprenal.00453.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/16/2020] [Accepted: 11/03/2020] [Indexed: 11/22/2022] Open
Abstract
Connexins (Cxs) form gap junctions for intercellular exchange of inorganic ions and messenger molecules. In the kidney, Cxs play essential roles within its compartments, but data on the precise cellular localization and cell type-related function of their isoforms are scarce. We tested whether Cx43 distribution is restricted to vascular and interstitial cells and whether medullary fibroblasts express Cx43 to coordinate profibrotic signaling. Confocal immunofluorescence techniques, ultrastructural labeling, and functional experiments in cell culture were performed. Cx43 was chiefly expressed in the vasculature but was absent from tubular epithelia. All arterial, arteriolar, and lymphatic endothelia showed continuous Cx43 signal along their borders. In the inner medulla, only the interstitium showed Cx43 signals, which were assigned to fibroblasts and their processes. Cultured Cx43-expressing medullary fibroblasts served to study the role of gap junctions in a profibrotic context. In a dye spreading assay, Cx43-sensitive diffusion of Lucifer yellow was dependent on gap junctional passage. The addition of transforming growth factor-β1 (5 ng/mL for 48 h) activated Cx43 biosynthesis and caused Cx43-sensitive transformation of the fibroblasts into a myofibroblast phenotype. This suggested that Cx43 gap junctional channels enable the coordination of profibrotic signaling between cells of the medullary interstitium. In summary, we demonstrate the presence of Cx43-expressing gap junctions within the two major renal compartments, the vasculature and interstitium. Endothelial Cx43 likely provides functions of an earlier-defined "electrical syncytium" within the vascular wall. Additionally, Cx43 facilitates profibrotic signaling between medullary interstitial fibroblasts.
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Affiliation(s)
- Yan Xu
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Junda Hu
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Duygu Elif Yilmaz
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité-Universitätsmedizin Berlin, Berlin, Germany
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12
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Himmel NJ, Rogers RT, Redd SK, Wang Y, Blount MA. Purinergic signaling is enhanced in the absence of UT-A1 and UT-A3. Physiol Rep 2021; 9:e14636. [PMID: 33369887 PMCID: PMC7769175 DOI: 10.14814/phy2.14636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 11/24/2022] Open
Abstract
ATP is an important paracrine regulator of renal tubular water and urea transport. The activity of P2Y2 , the predominant P2Y receptor of the medullary collecting duct, is mediated by ATP, and modulates urinary concentration. To investigate the role of purinergic signaling in the absence of urea transport in the collecting duct, we studied wild-type (WT) and UT-A1/A3 null (UT-A1/A3 KO) mice in metabolic cages to monitor urine output, and collected tissue samples for analysis. We confirmed that UT-A1/A3 KO mice are polyuric, and concurrently observed lower levels of urinary cAMP as compared to WT, despite elevated serum vasopressin (AVP) levels. Because P2Y2 inhibits AVP-stimulated transport by dampening cAMP synthesis, we suspected that, similar to other models of AVP-resistant polyuria, purinergic signaling is increased in UT-A1/A3 KO mice. In fact, we observed that both urinary ATP and purinergic-mediated prostanoid (PGE2 ) levels were elevated. Collectively, our data suggest that the reduction of medullary osmolality due to the lack of UT-A1 and UT-A3 induces an AVP-resistant polyuria that is possibly exacerbated by, or at least correlated with, enhanced purinergic signaling.
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Affiliation(s)
- Nathaniel J. Himmel
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Richard T. Rogers
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Sara K. Redd
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Yirong Wang
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
| | - Mitsi A. Blount
- Renal DivisionDepartment of MedicineEmory University School of MedicineAtlantaGAUSA
- Department of PhysiologyEmory University School of MedicineAtlantaGAUSA
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13
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Kreft E, Sałaga-Zaleska K, Sakowicz-Burkiewicz M, Dąbkowski K, Szczepánska-Konkel M, Jankowski M. Diabetes Affects the A1 Adenosine Receptor-Dependent Action of Diadenosine Tetraphosphate (Ap4A) on Cortical and Medullary Renal Blood Flow. J Vasc Res 2020; 58:38-48. [PMID: 33207336 DOI: 10.1159/000511461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 09/07/2020] [Indexed: 11/19/2022] Open
Abstract
Diabetes through adenosine A1 receptor (A1R) and P2 receptors (P2Rs) may lead to disturbances in renal microvasculature. We investigated the renal microvascular response to Ap4A, an agonist of P2Rs, in streptozotocin-induced diabetic rats. Using laser Doppler flowmetry, renal blood perfusion (RBP) was measured during infusion of Ap4A alone or in the presence of A1R antagonist, either DPCPX (8-cyclopentyl-1,3-dipropylxanthine) or 8-cyclopentyltheophylline (CPT). Ap4A induced a biphasic response in RBP: a phase of rapid decrease was followed by a rapid increase, which was transient in diabetic rats but extended for 30 min in nondiabetic rats. Phase of decreased RBP was not affected by DPCPX or CPT in either group. Early and extended increases in RBP were prevented by DPCPX and CPT in nondiabetic rats, while in diabetic rats, the early increase in RBP was not affected by these antagonists. A1R mRNA and protein levels were increased in isolated glomeruli of diabetic rats, but no changes were detected in P2Y1R and P2Y2R mRNA. Presence of unblocked A1R is a prerequisite for the P2R-mediated relaxing effect of Ap4A in nondiabetic conditions, but influence of A1R on P2R-mediated renal vasorelaxation is abolished under diabetic conditions.
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Affiliation(s)
- Ewelina Kreft
- Department of Clinical Chemistry, Medical University of Gdańsk, Gdańsk, Poland
| | | | | | - Kamil Dąbkowski
- Department of Clinical Chemistry, Medical University of Gdańsk, Gdańsk, Poland
| | | | - Maciej Jankowski
- Department of Clinical Chemistry, Medical University of Gdańsk, Gdańsk, Poland,
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14
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Gawrys O, Rak M, Baranowska I, Bobis-Wozowicz S, Szaro K, Madeja Z, Swiezewska E, Masnyk M, Chmielewski M, Karnas E, Kompanowska-Jezierska E. Polyprenol-Based Lipofecting Agents for In Vivo Delivery of Therapeutic DNA to Treat Hypertensive Rats. Biochem Genet 2020; 59:62-82. [PMID: 32767051 PMCID: PMC7846535 DOI: 10.1007/s10528-020-09992-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/28/2020] [Indexed: 11/26/2022]
Abstract
Development of efficient vectors for transfection is one of the major challenges in genetic engineering. Previous research demonstrated that cationic derivatives of polyisoprenoids (PTAI) may serve as carriers of nucleic acids. In the present study, the effectiveness of two PTAI-based formulations (PTAI-6–8 and 10–14) was investigated and compared to the commercial reagents. The purpose of applied gene therapy was to enhance the expression of vascular endothelial growth factor (VEGF-A) in the renal medulla of spontaneously hypertensive rats (SHR) and to test its potential as a novel antihypertensive intervention. In the first part of the study (in vitro), we confirmed that PTAI-based lipoplexes efficiently transfect XC rat sarcoma cells and are stable in 37 °C for 7 days. In the in vivo experiments, we administered selected lipoplexes directly to the kidneys of conscious SHR (via osmotic pumps). There were no blood pressure changes and VEGF-A level in renal medulla was significantly higher only for PTAI-10–14-based formulation. In conclusion, despite the promising results, we were not able to achieve VEGF-A expression level high enough to verify VEGF-A gene therapy usefulness in SHR. However, results of our study give important indications for the future development of PTAI-based DNA carriers and kidney-targeted gene delivery.
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Affiliation(s)
- Olga Gawrys
- Department of Renal and Body Fluid Physiology, M. Mossakowski Medical Research Centre, PAS, 5 A. Pawinskiego Street, 02-106, Warsaw, Poland.
| | - Monika Rak
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387, Kraków, Poland
| | - Iwona Baranowska
- Department of Renal and Body Fluid Physiology, M. Mossakowski Medical Research Centre, PAS, 5 A. Pawinskiego Street, 02-106, Warsaw, Poland
| | - Sylwia Bobis-Wozowicz
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387, Kraków, Poland
| | - Karolina Szaro
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387, Kraków, Poland
| | - Zbigniew Madeja
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387, Kraków, Poland
| | - Ewa Swiezewska
- Institute of Biochemistry and Biophysics, PAS, 5a A. Pawinskiego Street, 02-106, Warsaw, Poland
| | - Marek Masnyk
- Institute of Organic Chemistry, Polish Academy of Sciences, 44/52 M. Kasprzaka Street, 01-224, Warsaw, Poland
| | - Marek Chmielewski
- Institute of Organic Chemistry, Polish Academy of Sciences, 44/52 M. Kasprzaka Street, 01-224, Warsaw, Poland
| | - Elzbieta Karnas
- Department of Cell Biology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387, Kraków, Poland
- Malopolska Centre of Biotechnology, Jagiellonian University, 7 Gronostajowa St., 30-387, Kraków, Poland
| | - Elzbieta Kompanowska-Jezierska
- Department of Renal and Body Fluid Physiology, M. Mossakowski Medical Research Centre, PAS, 5 A. Pawinskiego Street, 02-106, Warsaw, Poland
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15
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Gay C, Letavernier E, Verpont MC, Walls M, Bazin D, Daudon M, Nassif N, Stéphan O, de Frutos M. Nanoscale Analysis of Randall's Plaques by Electron Energy Loss Spectromicroscopy: Insight in Early Biomineral Formation in Human Kidney. ACS Nano 2020; 14:1823-1836. [PMID: 31909991 DOI: 10.1021/acsnano.9b07664] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Idiopathic kidney stones originate mainly from calcium phosphate deposits at the tip of renal papillae, known as Randall's plaques (RPs), also detected in most human kidneys without stones. However, little is known about the mechanisms involved in RP formation. The localization and characterization of such nanosized objects in the kidney remain a real challenge, making their study arduous. This study provides a nanoscale analysis of the chemical composition and morphology of incipient RPs, characterizing in particular the interface between the mineral and the surrounding organic compounds. Relying on data gathered from a calculi collection, the morphology and chemical composition of incipient calcifications in renal tissue were determined using spatially resolved electron energy-loss spectroscopy. We detected microcalcifications and individual nanocalcifications found at some distance from the larger ones. Strikingly, concerning the smaller ones, we show that two types of nanocalcifications coexist: calcified organic vesicles and nanometric mineral granules mainly composed of calcium phosphate with carbonate in their core. Interestingly, some of these nanocalcifications present similarities with those reported in physiological bone or pathological cardiovascular biominerals, suggesting possible common formation mechanisms. However, the high diversity of these nanocalcifications suggests that several mechanisms may be involved (nucleation on a carbonate core or on organic compounds). In addition, incipient RPs also appear to present specific features at larger scales, revealing secondary calcified structures embedded in a fibrillar organic material. Our study proves that analogies exist between physiological and pathological biominerals and provides information to understand the physicochemical processes involved in pathological calcification formation.
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Affiliation(s)
- Clément Gay
- Laboratoire de Physique des Solides, CNRS UMR 8502 , Université de Paris-Saclay , F-91405 , Orsay , France
| | - Emmanuel Letavernier
- Sorbonne Université , UPMC Univ Paris 06, UMR S 1155, F-75020 , Paris , France
- INSERM , UMR S 1155, F-75020 , Paris , France
- Physiology Unit, APHP , Hôpital Tenon , F-75020 , Paris , France
| | - Marie-Christine Verpont
- Sorbonne Université , UPMC Univ Paris 06, UMR S 1155, F-75020 , Paris , France
- INSERM , UMR S 1155, F-75020 , Paris , France
| | - Michael Walls
- Laboratoire de Physique des Solides, CNRS UMR 8502 , Université de Paris-Saclay , F-91405 , Orsay , France
| | - Dominique Bazin
- Laboratoire de Chimie Physique, UMR 8000-CNRS , Université de Paris-Saclay , F-91405 , Orsay , France
| | - Michel Daudon
- Sorbonne Université , UPMC Univ Paris 06, UMR S 1155, F-75020 , Paris , France
- INSERM , UMR S 1155, F-75020 , Paris , France
- Physiology Unit, APHP , Hôpital Tenon , F-75020 , Paris , France
| | - Nadine Nassif
- Sorbonne Université , CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4 Place Jussieu , F-75005 , Paris , France
| | - Odile Stéphan
- Laboratoire de Physique des Solides, CNRS UMR 8502 , Université de Paris-Saclay , F-91405 , Orsay , France
| | - Marta de Frutos
- Laboratoire de Physique des Solides, CNRS UMR 8502 , Université de Paris-Saclay , F-91405 , Orsay , France
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16
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Rebelos E, Dadson P, Oikonen V, Iida H, Hannukainen JC, Iozzo P, Ferrannini E, Nuutila P. Renal hemodynamics and fatty acid uptake: effects of obesity and weight loss. Am J Physiol Endocrinol Metab 2019; 317:E871-E878. [PMID: 31550182 DOI: 10.1152/ajpendo.00135.2019] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human studies of renal hemodynamics and metabolism in obesity are insufficient. We hypothesized that renal perfusion and renal free fatty acid (FFA) uptake are higher in subjects with morbid obesity compared with lean subjects and that they both decrease after bariatric surgery. Cortical and medullary hemodynamics and metabolism were measured in 23 morbidly obese women and 15 age- and sex-matched nonobese controls by PET scanning of [15O]-H2O (perfusion) and 14(R,S)-[18F]fluoro-6-thia-heptadecanoate (FFA uptake). Kidney volume and radiodensity were measured by computed tomography, cardiac output by MRI. Obese subjects were re-studied 6 mo after bariatric surgery. Obese subjects had higher renal volume but lower radiodensity, suggesting accumulation of water and/or lipid. Both cardiac output and estimated glomerular filtration rate (eGFR) were increased by ~25% in the obese. Total renal blood flow was higher in the obese [885 (317) (expressed as median and interquartile range) vs. 749 (300) (expressed as means and SD) ml/min of controls, P = 0.049]. In both groups, regional blood perfusion was higher in the cortex than medulla; in either region, FFA uptake was ~50% higher in the obese as a consequence of higher circulating FFA levels. Following weight loss (26 ± 8 kg), total renal blood flow was reduced (P = 0.006). Renal volume, eGFR, cortical and medullary FFA uptake were decreased but not fully normalized. Obesity is associated with renal structural, hemodynamic, and metabolic changes. Six months after bariatric surgery, the hemodynamic changes are reversed and the structural changes are improved. On the contrary, renal FFA uptake remains increased, driven by high substrate availability.
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Affiliation(s)
- Eleni Rebelos
- Turku PET Centre, University of Turku, Turku, Finland
| | - Prince Dadson
- Turku PET Centre, University of Turku, Turku, Finland
| | - Vesa Oikonen
- Turku PET Centre, Turku University Hospital, Turku, Finland
| | - Hidehiro Iida
- Turku PET Centre, University of Turku, Turku, Finland
| | | | - Patricia Iozzo
- Turku PET Centre, University of Turku, Turku, Finland
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Ele Ferrannini
- Institute of Clinical Physiology, National Research Council (CNR), Pisa, Italy
| | - Pirjo Nuutila
- Turku PET Centre, University of Turku, Turku, Finland
- Department of Endocrinology, Turku University Hospital, Turku, Finland
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17
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Wilk A, Wiszniewska B, Rzuchowska A, Romanowski M, Różański J, Słojewski M, Ciechanowski K, Kalisińska E. Comparison of Copper Concentration Between Rejected Renal Grafts and Cancerous Kidneys. Biol Trace Elem Res 2019; 191:300-305. [PMID: 30645698 PMCID: PMC6706355 DOI: 10.1007/s12011-018-1621-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 12/17/2018] [Indexed: 12/21/2022]
Abstract
In the body, disorders in the composition and concentration of trace elements, including copper, can lead to the development of various alterations that may result in incorrect functioning of the kidneys. Data on the concentrations of copper in human kidneys are discussed; however, little is known about the concentration of trace elements within rejected renal grafts and kidneys with tumor lesions. The aim of our study was to compare the copper concentration between cancerous kidneys and rejected renal grafts with the division on renal cortex and renal medulla. Material consisted of kidneys from patients hospitalized at the Department of Urology and General Surgery and Transplantation of the Independent Public Clinical Hospital No. 2 at the Pomeranian Medical University in Szczecin, north-western Poland. The study material consisted of kidneys with tumor lesions (n = 33), and renal grafts (n = 10), obtained from patients belongs to the north-western areas of Poland. The examination was performed using ICP-AES method. Regarding the pathological kidneys, excluding grafts, the concentration of Cu in the renal cortex was 52% higher than in medullary region and the difference between the compared concentrations was statistically confirmed (p < 0.05). Taking into account renal grafts, the concentration of Cu in the medulla was slightly lower than in the cortex (less than 3%). In summary, copper in rejected and cancerous kidneys tends to accumulate in higher amount in the renal cortex than medulla, what can be explained by the fact that renal corpuscles, where the first phase of filtration is performed, are located only in the cortical region of the kidney. Furthermore, renal grafts accumulate significantly less copper than kidneys with neoplastic changes, what could have been caused by immunosuppressive medicines used by the graft recipients. The lower copper concentration in renal grafts could be a consequence of the altered immune system, including inflammatory process or/and non-immune mechanisms. Additionally, cancerous and non-cancerous kidneys exhibit different perfusion rate in renal glomeruli, what can finally lead to disparity in chemical elements concentration, including copper.
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Affiliation(s)
- Aleksandra Wilk
- Department of Histology and Embryology, Pomeranian Medical University, Szczecin, Poland.
| | - Barbara Wiszniewska
- Department of Histology and Embryology, Pomeranian Medical University, Szczecin, Poland
| | - Anna Rzuchowska
- Department of Biology and Medical Parasitology, Pomeranian Medical University, Szczecin, Poland
| | - Maciej Romanowski
- Department and Clinic of General Surgery and Transplantology, Medical University of Warsaw, Warsaw, Poland
| | - Jacek Różański
- Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland
| | - Marcin Słojewski
- Department of Urology and Urological Oncology, Pomeranian Medical University, al. Powstańców Wielkopolskich 72, 70-111, Szczecin, Poland
| | - Kazimierz Ciechanowski
- Department of Nephrology, Transplantology and Internal Medicine, Pomeranian Medical University, Szczecin, Poland
| | - Elżbieta Kalisińska
- Department of Biology and Medical Parasitology, Pomeranian Medical University, Szczecin, Poland
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18
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Deshpande V, Kao A, Raghuram V, Datta A, Chou CL, Knepper MA. Phosphoproteomic identification of vasopressin V2 receptor-dependent signaling in the renal collecting duct. Am J Physiol Renal Physiol 2019; 317:F789-F804. [PMID: 31313956 PMCID: PMC6843035 DOI: 10.1152/ajprenal.00281.2019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 12/15/2022] Open
Abstract
Vasopressin controls water balance largely through PKA-dependent effects to regulate the collecting duct water channel aquaporin-2 (AQP2). Although considerable information has accrued regarding the regulation of water and solute transport in collecting duct cells, information is sparse regarding the signaling connections between PKA and transport responses. Here, we exploited recent advancements in protein mass spectrometry to perform a comprehensive, multiple-replicate analysis of changes in the phosphoproteome of native rat inner medullary collecting duct cells in response to the vasopressin V2 receptor-selective agonist 1-desamino-8D-arginine vasopressin. Of the 10,738 phosphopeptides quantified, only 156 phosphopeptides were significantly increased in abundance, and only 63 phosphopeptides were decreased, indicative of a highly selective response to vasopressin. The list of upregulated phosphosites showed several general characteristics: 1) a preponderance of sites with basic (positively charged) amino acids arginine (R) and lysine (K) in position -2 and -3 relative to the phosphorylated amino acid, consistent with phosphorylation by PKA and/or other basophilic kinases; 2) a greater-than-random likelihood of sites previously demonstrated to be phosphorylated by PKA; 3) a preponderance of sites in membrane proteins, consistent with regulation by membrane association; and 4) a greater-than-random likelihood of sites in proteins with class I COOH-terminal PDZ ligand motifs. The list of downregulated phosphosites showed a preponderance of those with proline in position +1 relative to the phosphorylated amino acid, consistent with either downregulation of proline-directed kinases (e.g., MAPKs or cyclin-dependent kinases) or upregulation of one or more protein phosphatases that selectively dephosphorylate such sites (e.g., protein phosphatase 2A). The phosphoproteomic data were used to create a web resource for the investigation of G protein-coupled receptor signaling and regulation of AQP2-mediated water transport.
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Affiliation(s)
- Venkatesh Deshpande
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Anika Kao
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Viswanathan Raghuram
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Arnab Datta
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Chung-Lin Chou
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
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19
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Dugbartey GJ, Quinn B, Luo L, Mickelsen DM, Ture SK, Morrell CN, Czyzyk J, Doyley MM, Yan C, Berk BC, Korshunov VA. The Protective Role of Natriuretic Peptide Receptor 2 against High Salt Injury in the Renal Papilla. Am J Pathol 2019; 189:1721-1731. [PMID: 31220449 PMCID: PMC6724224 DOI: 10.1016/j.ajpath.2019.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/11/2019] [Accepted: 05/28/2019] [Indexed: 12/20/2022]
Abstract
Mutations in natriuretic peptide receptor 2 (Npr2) gene cause a rare form of short-limbed dwarfism, but its physiological effects have not been well studied. Human and mouse genetic data suggest that Npr2 in the kidney plays a role in salt homeostasis. Herein, we described anatomic changes within renal papilla of Npr2 knockout (Npr2-/-) mice. Dramatic reduction was found in diuresis, and albuminuria was evident after administration of 1% NaCl in drinking water in Npr2-/- and heterozygous (Npr2+/-) mice compared with their wild-type (Npr2+/+) littermates. There was indication of renal epithelial damage accompanied by high numbers of red blood cells and inflammatory cells (macrophage surface glycoproteins binding to galectin-3) and an increase of renal epithelial damage marker (T-cell Ig and mucin domain 1) in Npr2-/- mice. Addition of 1% NaCl tended to increase apoptotic cells (cleaved caspase 3) in the renal papilla of Npr2-/- mice. In vitro, genetic silencing of the Npr2 abolished protective effects of C-type natriuretic peptide, a ligand for Npr2, against death of M-1 kidney epithelial cells exposed to 360 mmol/L NaCl. Finally, significantly lower levels of expression of the NPR2 protein were detected in renal samples of hypertensive compared with normotensive human subjects. Taken together, these findings suggest that Npr2 is essential to protect renal epithelial cells from high concentrations of salt and prevent kidney injury.
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Affiliation(s)
- George J Dugbartey
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Breandan Quinn
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Lingfeng Luo
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Deanne M Mickelsen
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Sara K Ture
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Craig N Morrell
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Jan Czyzyk
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Marvin M Doyley
- Department of Electrical and Computer Engineering, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Chen Yan
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York
| | - Bradford C Berk
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York; Department of Medicine, Neurorestoration Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York.
| | - Vyacheslav A Korshunov
- Aab Cardiovascular Research Institute, Hajim School of Engineering and Applied Sciences, University of Rochester, Rochester, New York.
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20
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Osis G, Webster KL, Harris AN, Lee HW, Chen C, Fang L, Romero MF, Khattri RB, Merritt ME, Verlander JW, Weiner ID. Regulation of renal NaDC1 expression and citrate excretion by NBCe1-A. Am J Physiol Renal Physiol 2019; 317:F489-F501. [PMID: 31188034 PMCID: PMC6732450 DOI: 10.1152/ajprenal.00015.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/20/2019] [Accepted: 06/07/2019] [Indexed: 11/22/2022] Open
Abstract
Citrate is critical for acid-base homeostasis and to prevent calcium nephrolithiasis. Both metabolic acidosis and hypokalemia decrease citrate excretion and increase expression of Na+-dicarboxylate cotransporter 1 (NaDC1; SLC13A2), the primary protein involved in citrate reabsorption. However, the mechanisms transducing extracellular signals and mediating these responses are incompletely understood. The purpose of the present study was to determine the role of the Na+-coupled electrogenic bicarbonate cotransporter (NBCe1) A variant (NBCe1-A) in citrate metabolism under basal conditions and in response to acid loading and hypokalemia. NBCe1-A deletion increased citrate excretion and decreased NaDC1 expression in the proximal convoluted tubules (PCT) and proximal straight tubules (PST) in the medullary ray (PST-MR) but not in the PST in the outer medulla (PST-OM). Acid loading wild-type (WT) mice decreased citrate excretion. NaDC1 expression increased only in the PCT and PST-MR and not in the PST-MR. In NBCe1-A knockout (KO) mice, the acid loading change in citrate excretion was unaffected, changes in PCT NaDC1 expression were blocked, and there was an adaptive increase in PST-MR. Hypokalemia in WT mice decreased citrate excretion; NaDC1 expression increased only in the PCT and PST-MR. NBCe1-A KO blocked both the citrate and NaDC1 changes. We conclude that 1) adaptive changes in NaDC1 expression in response to metabolic acidosis and hypokalemia occur specifically in the PCT and PST-MR, i.e., in cortical proximal tubule segments; 2) NBCe1-A is necessary for normal basal, metabolic acidosis and hypokalemia-stimulated citrate metabolism and does so by regulating NaDC1 expression in cortical proximal tubule segments; and 3) adaptive increases in PST-OM NaDC1 expression occur in NBCe1-A KO mice in response to acid loading that do not occur in WT mice.
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Affiliation(s)
- Gunars Osis
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Kierstin L Webster
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Autumn N Harris
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - Hyun-Wook Lee
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Chao Chen
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Lijuan Fang
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Ram B Khattri
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - I David Weiner
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
- Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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21
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Gee MT, Kurtz I, Pannabecker TL. Expression of SLC4A11 protein in mouse and rat medulla: a candidate transporter involved in outer medullary ammonia recycling. Physiol Rep 2019; 7:e14089. [PMID: 31124301 PMCID: PMC6533174 DOI: 10.14814/phy2.14089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 04/10/2019] [Indexed: 01/27/2023] Open
Abstract
SLC4A11 is a multifunctional membrane transporter involved with H+ transport, NH3 and alkaline pH stimulated H+ transport, and water transport. The role of SLC4A11 in the kidney is not well understood. A prior study has shown that in murine kidney, SLC4A11/LacZ staining is primarily in the long-looped descending thin limb (DTL) as determined by colocalization with aquaporin 1 (AQP1), a protein that is expressed in some, but not all, descending thin limb segments. Using a previously characterized polyclonal antibody, we demonstrate the selective expression of SLC4A11 in the upper DTLs (which are AQP1-positive) in the outer medulla and inner medulla with little or no expression in the lower DTLs (which are AQP-1-null). SLC4A11 also colocalized with AQP1 and the urea transporter UT-B in the mouse descending vasa recta, but was absent in mouse and rat ascending vasa recta. Mouse, but not rat, outer medullary collecting duct cells also labeled for SLC4A11. Our results are compatible with the hypothesis that in the inner stripe of the outer medulla, SLC4A11 plays a role in the countercurrent transport of ammonia absorbed from the outer medullary thick ascending limb and secreted into the long-looped DTLs. SLC4A11 can potentially modulate the rate of ammonia transport in the mouse outer medullary collecting duct. Our data suggest functionally unique SLC4A11 pathways in mouse and rat and complement previous studies of DTL Na+ , urea and water permeability indicating that the upper and lower DTLs of long-looped nephrons are functionally distinct.
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Affiliation(s)
- Michael T. Gee
- Department of PhysiologyBanner‐University Medical CenterUniversity of ArizonaTucsonAZ85724
| | - Ira Kurtz
- Division of NephrologyDavid Geffen School of MedicineUniversity of California, Los Angeles (UCLA)Los AngelesCA
- Brain Research InstituteDavid Geffen School of MedicineUniversity of California, Los Angeles (UCLA)Los AngelesCA
| | - Thomas L. Pannabecker
- Department of PhysiologyBanner‐University Medical CenterUniversity of ArizonaTucsonAZ85724
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Rogers RT, Sun MA, Yue Q, Bao HF, Sands JM, Blount MA, Eaton DC. Lack of urea transporters, UT-A1 and UT-A3, increases nitric oxide accumulation to dampen medullary sodium reabsorption through ENaC. Am J Physiol Renal Physiol 2019; 316:F539-F549. [PMID: 30539654 PMCID: PMC6459308 DOI: 10.1152/ajprenal.00166.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 11/19/2018] [Accepted: 11/30/2018] [Indexed: 12/31/2022] Open
Abstract
Although the role of urea in urine concentration is known, the effect of urea handling by the urea transporters (UTs), UT-A1 and UT-A3, on sodium balance remains elusive. Serum and urinary sodium concentration is similar between wild-type mice (WT) and UT-A3 null (UT-A3 KO) mice; however, mice lacking both UT-A1 and UT-A3 (UT-A1/A3 KO) have significantly lower serum sodium and higher urinary sodium. Protein expression of renal sodium transporters is unchanged among all three genotypes. WT, UT-A3 KO, and UT-A1/A3 KO acutely respond to hydrochlorothiazide and furosemide; however, UT-A1/A3 KO fail to show a diuretic or natriuretic response following amiloride administration, indicating that baseline epithelial Na+ channel (ENaC) activity is impaired. UT-A1/A3 KO have more ENaC at the apical membrane than WT mice, and single-channel analysis of ENaC in split-open inner medullary collecting duct (IMCD) isolated in saline shows that ENaC channel density and open probability is higher in UT-A1/A3 KO than WT. UT-A1/A3 KO excrete more urinary nitric oxide (NO), a paracrine inhibitor of ENaC, and inner medullary nitric oxide synthase 1 mRNA expression is ~40-fold higher than WT. Because endogenous NO is unstable, ENaC activity was reassessed in split-open IMCD with the NO donor PAPA NONOate [1-propanamine-3-(2-hydroxy-2-nitroso-1-propylhydrazine)], and ENaC activity was almost abolished in UT-A1/A3 KO. In summary, loss of both UT-A1 and UT-A3 (but not UT-A3 alone) causes elevated medullary NO production and salt wasting. NO inhibition of ENaC, despite elevated apical accumulation of ENaC in UT-A1/A3 KO IMCD, appears to be the main contributor to natriuresis in UT-A1/A3 KO mice.
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Affiliation(s)
- Richard T Rogers
- Renal Division, Department of Medicine, Emory University School of Medicine , Atlanta, Georgia
| | - Michael A Sun
- Renal Division, Department of Medicine, Emory University School of Medicine , Atlanta, Georgia
| | - Qiang Yue
- Department of Physiology, Emory University School of Medicine , Atlanta, Georgia
| | - Hui-Fang Bao
- Department of Physiology, Emory University School of Medicine , Atlanta, Georgia
| | - Jeff M Sands
- Renal Division, Department of Medicine, Emory University School of Medicine , Atlanta, Georgia
- Department of Physiology, Emory University School of Medicine , Atlanta, Georgia
| | - Mitsi A Blount
- Renal Division, Department of Medicine, Emory University School of Medicine , Atlanta, Georgia
- Department of Physiology, Emory University School of Medicine , Atlanta, Georgia
| | - Douglas C Eaton
- Department of Physiology, Emory University School of Medicine , Atlanta, Georgia
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23
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Christensen M, Schiffer TA, Gustafsson H, Krag SP, Nørregaard R, Palm F. Metformin attenuates renal medullary hypoxia in diabetic nephropathy through inhibition uncoupling protein-2. Diabetes Metab Res Rev 2019; 35:e3091. [PMID: 30345618 DOI: 10.1002/dmrr.3091] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 10/03/2018] [Accepted: 10/16/2018] [Indexed: 11/09/2022]
Abstract
BACKGROUND The purpose of the study is to examine the effect of metformin on oxygen metabolism and mitochondrial function in the kidney of an animal model of insulinopenic diabetes in order to isolate any renoprotective effect from any concomitant effect on blood glucose homeostasis. METHODS Sprague-Dawley rats were injected with streptozotocin (STZ) (50 mg kg-1 ) and when stable started on metformin treatment (250 mg kg-1 ) in the drinking water. Rats were prepared for in vivo measurements 25 to 30 days after STZ injection, where renal function, including glomerular filtration rate and sodium transport, was estimated in anesthetized rats. Intrarenal oxygen tension was measured using oxygen sensors. Furthermore, mitochondrial function was assessed in mitochondria isolated from kidney cortex and medulla analysed by high-resolution respirometry, and superoxide production was evaluated using electron paramagnetic resonance. RESULTS Insulinopenic rats chronically treated with metformin for 4 weeks displayed improved medullary tissue oxygen tension despite of no effect of metformin on blood glucose homeostasis. Metformin reduced UCP2-dependent LEAK and differentially affected medullary mitochondrial superoxide radical production in control and diabetic rats. CONCLUSIONS Metformin attenuates diabetes-induced renal medullary tissue hypoxia in an animal model of insulinopenic type 1 diabetes. The results suggest that the mechanistic pathway to attenuate the diabetes-induced medullary hypoxia is independent of blood glucose homeostasis and includes reduced UCP2-mediated mitochondrial proton LEAK.
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Affiliation(s)
| | - Tomas A Schiffer
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Håkan Gustafsson
- Department of Radiology Norrköping and Department of Medical and Health Sciences, Linköping University, Linköping, Sweden
| | | | - Rikke Nørregaard
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Fredrik Palm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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24
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Daneva Z, Dempsey SK, Ahmad A, Li N, Li PL, Ritter JK. Diuretic, Natriuretic, and Vasodepressor Activity of a Lipid Fraction Enhanced in Medium of Cultured Mouse Medullary Interstitial Cells by a Selective Fatty Acid Amide Hydrolase Inhibitor. J Pharmacol Exp Ther 2019; 368:187-198. [PMID: 30530623 PMCID: PMC6337005 DOI: 10.1124/jpet.118.252320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 12/04/2018] [Indexed: 01/09/2023] Open
Abstract
The relationship between the endocannabinoid system in the renal medulla and the long-term regulation of blood pressure is not yet understood. To investigate the possible role of the endocannabinoid system in renomedullary interstitial cells, mouse medullary interstitial cells (MMICs) were obtained, cultured, and characterized for their responses to treatment with a selective inhibitor of fatty acid amide hydrolase, PF-3845 (N-3-pyridinyl-4-[[3-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenyl]methyl]-1-piperidinecarboxamide). Treatment of MMICs with PF-3845 increased cytoplasmic lipid granules detected by Sudan Black B staining and multilamellar bodies identified by transmission electron microscopy. High-performance liquid chromatography (HPLC) analyses of lipid extracts of MMIC culture medium revealed a 205-nm absorbing peak that showed responsiveness to PF-3845 treatment. The biologic activities of the PF-3845-induced product (PIP) isolated by HPLC were investigated in anesthetized, normotensive surgically instrumented mice. Intramedullary and intravenous infusion of PIP at low dose rates (0.5-1 area units under the peak/10 min) stimulated diuresis and natriuresis, whereas these parameters returned toward baseline at higher doses but mean arterial pressure (MAP) was lowered. Whereas intravenous bolus doses of PIP stimulated diuresis, the glomerular filtration rate, and medullary blood flow (MBF) and reduced or had no effect on MAP, an intraperitoneal bolus injection of PIP reduced MAP, increased MBF, and had no effect on urine parameters. These data support a model whereby PF-3845 treatment of MMICs results in increased secretion of a neutral lipid that acts directly to promote diuresis and natriuresis and indirectly through metabolites to produce vasodepression. Efforts to identify the structure of the PF-3845-induced lipid and its relationship to the previously proposed renomedullary antihypertensive lipids are ongoing.
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Affiliation(s)
- Zdravka Daneva
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Sara K Dempsey
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Ashfaq Ahmad
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Ningjun Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Pin-Lan Li
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
| | - Joseph K Ritter
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, Virginia
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Abstract
Background Renal hypoxia, implicated as crucial factor in onset and progression of chronic kidney disease, may be attributed to reduced nitric oxide because nitric oxide dilates vasculature and inhibits mitochondrial oxygen consumption. We hypothesized that chronic nitric oxide synthase inhibition would induce renal hypoxia. Methods and Results Oxygen-sensitive electrodes, attached to telemeters, were implanted in either renal cortex (n=6) or medulla (n=7) in rats. After recovery and stabilization, baseline oxygenation ( pO 2) was recorded for 1 week. To inhibit nitric oxide synthase, N-ω-nitro-l-arginine (L-NNA; 40 mg/kg/day) was administered via drinking water for 2 weeks. A separate group (n=8), instrumented with blood pressure telemeters, followed the same protocol. L-NNA rapidly induced hypertension (165±6 versus 108±3 mm Hg; P<0.001) and proteinuria (79±12 versus 17±2 mg/day; P<0.001). Cortical pO 2, after initially dipping, returned to baseline and then increased. Medullary pO 2 decreased progressively (up to -19±6% versus baseline; P<0.05). After 14 days of L-NNA, amplitude of diurnal medullary pO 2 was decreased (3.7 [2.2-5.3] versus 7.9 [7.5-8.4]; P<0.01), whereas amplitudes of blood pressure and cortical pO 2 were unaltered. Terminal glomerular filtration rate (1374±74 versus 2098±122 μL/min), renal blood flow (5014±336 versus 9966±905 μL/min), and sodium reabsorption efficiency (13.0±0.8 versus 22.8±1.7 μmol/μmol) decreased (all P<0.001). Conclusions For the first time, we show temporal development of renal cortical and medullary oxygenation during chronic nitric oxide synthase inhibition in unrestrained conscious rats. Whereas cortical pO 2 shows transient changes, medullary pO 2 decreased progressively. Chronic L-NNA leads to decreased renal perfusion and sodium reabsorption efficiency, resulting in progressive medullary hypoxia, suggesting that juxtamedullary nephrons are potentially vulnerable to prolonged nitric oxide depletion.
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Affiliation(s)
- Tonja W. Emans
- Internal Medicine‐NephrologyAmsterdam UMC / Academic Medical Centre at the University of AmsterdamThe Netherlands
- Nephrology and HypertensionUniversity Medical Centre UtrechtThe Netherlands
| | - Ben J. Janssen
- Pharmacology and ToxicologyMaastricht UniversityThe Netherlands
| | - Jaap A. Joles
- Nephrology and HypertensionUniversity Medical Centre UtrechtThe Netherlands
| | - C.T. Paul Krediet
- Internal Medicine‐NephrologyAmsterdam UMC / Academic Medical Centre at the University of AmsterdamThe Netherlands
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Lu Z, Al-Obaidy K, Cheng L, Perry KD, Grignon DJ, Williamson SR. Immunohistochemical characteristics of renomedullary interstitial cell tumor: a study of 41 tumors with emphasis on differential diagnosis of mesenchymal neoplasms. Hum Pathol 2018; 82:46-50. [PMID: 30031100 DOI: 10.1016/j.humpath.2018.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/21/2018] [Accepted: 07/03/2018] [Indexed: 11/20/2022]
Abstract
Renomedullary interstitial cell tumors (RMICTs) are almost always incidentally identified either at autopsy or upon resection of the kidney for other reasons. However, rare cases that are large, resulting in a clinical mass, have been reported. The immunohistochemical phenotype of usual, incidental RMICT using modern soft tissue tumor markers is largely unknown, however, providing little information to aid in classification of larger or atypical tumors. We retrieved 41 RMICTs from 36 patients and studied pathologic characteristics including morphology, immunohistochemistry (S100, keratin AE1/AE3, smooth muscle actin, desmin, estrogen and progesterone receptors, calponin, CD34, CD35), and histochemical staining. Data collected included age, sex, tumor size, laterality, and indication for kidney examination. RMICTs (n = 41) were identified in 23 men and 13 women, with a mean age of 57 years (range, 24-83 years); tumor sizes ranged from less than 1 to 13 mm (median, 4 mm). Kidneys were resected for 32 tumors, 1 chronic pyelonephritis, 1 trauma, and 2 autopsies. All (41; 100%) had entrapped renal tubules, 5 (12%) of which included cystic or dilated tubules. Most (35; 85%) had collagenous fibers, all of which were negative for Congo red. RMICT demonstrates a largely negative immunohistochemical phenotype with weak-to-moderate labeling for smooth muscle actin and calponin that is substantially less than myofibroblastic lesions. Positive staining for estrogen and progesterone receptors is common (61%), which could overlap with mixed epithelial and stromal tumor and other entities; however, staining is typically weak. CD34 is usually negative, with occasional weak labeling, in contrast to solitary fibrous tumor.
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Affiliation(s)
- Zhichun Lu
- Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, MI 48202, USA
| | - Khaleel Al-Obaidy
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Liang Cheng
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kyle D Perry
- Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, MI 48202, USA
| | - David J Grignon
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sean R Williamson
- Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, MI 48202, USA.
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Abstract
INTRODUCTION Metabolomics is a promising approach for discovery of relevant biomarkers in cells, tissues, organs, and biofluids for disease identification and prediction. The field has mostly relied on blood-based biofluids (serum, plasma, urine) as non-invasive sources of samples as surrogates of tissue or organ-specific conditions. However, the tissue specificity of metabolites pose challenges in translating blood metabolic profiles to organ-specific pathophysiological changes, and require further downstream analysis of the metabolites. OBJECTIVES As part of this project, we aim to develop and optimize an efficient extraction protocol for the analysis of kidney tissue metabolites representative of key primate metabolic pathways. METHODS Kidney cortex and medulla tissues of a baboon were homogenized and extracted using eight different extraction protocols including methanol/water, dichloromethane/methanol, pure methanol, pure water, water/methanol/chloroform, methanol/chloroform, methanol/acetonitrile/water, and acetonitrile/isopropanol/water. The extracts were analyzed by a two-dimensional gas chromatography time-of-flight mass-spectrometer (2D GC-ToF-MS) platform after methoximation and silylation. RESULTS Our analysis quantified 110 shared metabolites in kidney cortex and medulla tissues from hundreds of metabolites found among the eight different solvent extractions spanning low to high polarities. The results revealed that medulla is metabolically richer compared to the cortex. Dichloromethane and methanol mixture (3:1) yielded highest number of metabolites across both the tissue types. Depending on the metabolites of interest, tissue type, and the biological question, different solvents can be used to extract specific groups of metabolites. CONCLUSION This investigation provides insights into selection of extraction solvents for detection of classes of metabolites in renal cortex and medulla, which is fundamentally important for identification of prognostic and diagnostic metabolic kidney biomarkers for future therapeutic applications.
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Affiliation(s)
- Biswapriya B Misra
- Center for Precision Medicine, Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, 78227, USA.
| | - Ram P Upadhayay
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
| | - Laura A Cox
- Center for Precision Medicine, Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
| | - Michael Olivier
- Center for Precision Medicine, Department of Internal Medicine, Section of Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, 78227, USA
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Kikuchi K, Ishimatsu K, Zhang S, Dimitrov IE, Honda H, Sherry AD, Takahashi M. Presaturation Power Adjusted Pulsed CEST: A Method to Increase Independence of Target CEST Signals. Contrast Media Mol Imaging 2018; 2018:3141789. [PMID: 29853805 PMCID: PMC5964408 DOI: 10.1155/2018/3141789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 03/25/2018] [Indexed: 11/18/2022]
Abstract
Chemical exchange saturation transfer (CEST) imaging has been demonstrated to discuss the concentration changes of amide proton, glutamate, creatine, or glucose measured at 3.5, 3.0, 2.0, and 1.0-1.2 ppm. However, these peaks in z-spectra are quite broad and overlap with each other, and thus, the independence of a CEST signal on any specific metabolite is still open to question. Here, we described whether there was interference among the CEST signals and how these CEST signals behave when the power of the presaturation pulse was changed. Based on these results, further experiments were designed to investigate a method to increase the independence of the CEST signal in both phantoms and animals. The result illustrates a clear interference among CEST signals. A presaturation power adjusted pulsed- (PPAP-) CEST method which was designed based on the exchange rates of the metabolites can be used to remove contributions from other exchanging species in the same sample. Further, the method was shown to improve the independence of the glutamate signal in vivo in the renal medulla in mice. The PPAP-CEST method has the potential to increase the independence of any target CEST signals in vivo by choosing the appropriate combination of pulse amplitudes and durations.
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Affiliation(s)
- Kazufumi Kikuchi
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Keisuke Ishimatsu
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shanrong Zhang
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ivan E. Dimitrov
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Philips Healthcare, Gainesville, FL, USA
| | - Hiroshi Honda
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Masaya Takahashi
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Goto I, Okamoto R, Hashizume R, Suzuki N, Ito R, Yamanaka K, Saito H, Kiyonari H, Tawara I, Kageyama Y, Ogihara Y, Ali Y, Yamada N, Katayama N, Ito M. Renal papillary tip extract stimulates BNP production and excretion from cardiomyocytes. PLoS One 2018; 13:e0197078. [PMID: 29734386 PMCID: PMC5937764 DOI: 10.1371/journal.pone.0197078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/25/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Brain natriuretic peptide (BNP) is an important biomarker for patients with cardiovascular diseases, including heart failure, hypertension and cardiac hypertrophy. It is also known that BNP levels are relatively higher in patients with chronic kidney disease and no heart disease; however, the mechanism remains unclear. METHODS AND RESULTS We developed a BNP reporter mouse and occasionally found that this promoter was activated specifically in the papillary tip of the kidneys, and its activation was not accompanied by BNP mRNA expression. No evidence was found to support the existence of BNP isoforms or other nucleotide expression apart from BNP and tdTomato. The pBNP-tdTomato-positive cells were interstitial cells and were not proliferative. Unexpectedly, both the expression and secretion of BNP increased in primary cultured neonatal cardiomyocytes after their treatment with an extract of the renal papillary tip. Intraperitoneal injection of the extract of the papillary tips reduced blood pressure from 210 mmHg to 165 mmHg, the decrease being accompanied by an increase in serum BNP and urinary cGMP production in stroke-prone spontaneously hypertensive (SHR-SP) rats. Furthermore the induction of BNP by the papillary extract from rats with heart failure due to myocardial infarction was increased in cardiomyocytes. CONCLUSIONS These results suggested that the papillary tip express a substance that can stimulate BNP production and secretion from cardiomyocytes.
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Affiliation(s)
- Itaru Goto
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Ryuji Okamoto
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
- * E-mail:
| | - Ryotaro Hashizume
- Department of Pathology and Matrix Biology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Noboru Suzuki
- Department of Animal Genomics, Functional Genomics Institute, Mie University Life Science Research Center, Tsu, Mie, Japan
| | - Rie Ito
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Keiichi Yamanaka
- Department of Dermatology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Hiromitsu Saito
- Department of Animal Genomics, Functional Genomics Institute, Mie University Life Science Research Center, Tsu, Mie, Japan
| | - Hiroshi Kiyonari
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, Kobe, Hyogo, Japan
- Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe, Hyogo, Japan
| | - Isao Tawara
- Department of Hematology and Oncology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Yuki Kageyama
- Department of Hematology and Oncology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Yoshito Ogihara
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Yusuf Ali
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Norikazu Yamada
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Naoyuki Katayama
- Department of Hematology and Oncology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Masaaki Ito
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
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Sherer BA, Chen L, Kang M, Shimotake AR, Wiener SV, Chi T, Stoller ML, Ho SP. A continuum of mineralization from human renal pyramid to stones on stems. Acta Biomater 2018; 71:72-85. [PMID: 29428569 DOI: 10.1016/j.actbio.2018.01.040] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/21/2017] [Accepted: 01/25/2018] [Indexed: 01/28/2023]
Abstract
The development of new modalities for kidney stone prevention rests upon understanding the progression of mineralization within the renal pyramid. The progression from small foci of mineralized volumes within the renal pyramid to larger interstitial plaques that ultimately lead into clinically detectable calcium-based stones on calcium phosphate stems will be presented through correlative microscopy approach. High resolution X-ray computed tomography (micro-XCT), electron microscopy, and energy dispersive X-ray (EDX) compositional analyses of interstitial plaques, stems, and attached stones were performed. Increase in mineral density progressed with mineralization severity, with the highest mineral densities detected within mature Randall's plaque and stems to which kidney stones were attached. EDX analyses revealed variable elemental composition within interstitial plaque, stems, and stones. Micro-XCT reconstructions of stones with stems enabled visualization of unoccluded tubules within stems, with average tubule diameters corresponding to thin limbs of Henle, blood vessels, and collecting ducts. Correlative microscopy confirmed that the progression of mineralization leading to calcium-based nephrolithiasis occurs through a continuum involving four anatomically and structurally distinct biomineralization regions: 1) proximal intratubular mineralization within the renal pyramid; 2) interstitial Randall's plaque near the tip of the papilla; 3) emerging plaque (stems); and, 4) the body of heterogeneous stones. STATEMENT OF SIGNIFICANCE Nephrolithiasis is a common condition affecting nearly 1 in 11 Americans. The most common type of stone, calcium oxalate is known to form on a calcium phosphate deposit on the renal papilla known as Randall's plaque. Novel imaging techniques have identified distinct regions of biomineralization not just at the tip, but throughout the renal papilla. The classic understanding of Randall's plaque formation is reformulated using correlative imaging techniques. This study establishes a stepwise progression of anatomically-specific biomineralization events including, 1) proximal intratubular mineralization within the renal pyramid; 2) interstitial Randall's plaque near the tip of the papilla; 3) emerging plaque (stems); and, 4) the body of heterogeneous stones, and provides insights into the need for plausible site-specific therapeutic intervention.
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Affiliation(s)
- Benjamin A Sherer
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, United States
| | - Ling Chen
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, CA 94143, United States
| | - Misun Kang
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, CA 94143, United States
| | - Alex R Shimotake
- Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, CA 94143, United States
| | - Scott V Wiener
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, United States
| | - Tom Chi
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, United States
| | - Marshall L Stoller
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, United States
| | - Sunita P Ho
- Department of Urology, University of California San Francisco, San Francisco, CA 94143, United States; Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California San Francisco, San Francisco, CA 94143, United States.
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Ozurumba E, Mathew O, Ranganna K, Choi M, Oyekan A. Regulation of hypoxia inducible factor/prolyl hydroxylase binding domain proteins 1 by PPARα and high salt diet. J Basic Clin Physiol Pharmacol 2018; 29:165-173. [PMID: 29500923 DOI: 10.1515/jbcpp-2017-0074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 11/08/2017] [Indexed: 06/08/2023]
Abstract
BACKGROUND Hypoxia inducible factor (HIF)/prolyl hydroxylase domain (PHD)-containing proteins are involved in renal adaptive response to high salt (HS). Peroxisome proliferator activated receptor alpha (PPARα), a transcription factor involved in fatty acid oxidation is implicated in the regulation of renal function. As both HIF-1α/PHD and PPARα contribute to the adaptive changes to altered oxygen tension, this study tested the hypothesis that PHD-induced renal adaptive response to HS is PPARα-dependent. METHODS PPARα wild type (WT) and knock out (KO) mice were fed a low salt (LS) (0.03% NaCl) or a HS (8% NaCl) diet for 8 days and treated with hydralazine. PPARα and heme oxygenase (HO)-1 expression were evaluated in the kidney cortex and medulla. A 24-h urinary volume (UV), sodium excretion (UNaV), and nitrite excretion (UNOx V) were also determined. RESULTS PHD1 expression was greater in the medulla as compared to the cortex of PPARα WT mice (p<0.05) fed with a LS (0.03% NaCl) diet. The HS diet (8% NaCl) downregulated PHD1 expression in the medulla (p<0.05) but not the cortex of WT mice whereas expression was downregulated in the cortex (p<0.05) and medulla (p<0.05) of KO mice. These changes were accompanied by HS-induced diuresis (p<0.05) and natriuresis (p<0.05) that were greater in WT mice (p<0.05). Similarly, UNOx V, index of renal nitric oxide synthase (NOS) activity or availability and heme oxygenase (HO)-1 expression was greater in WT (p<0.05) but unchanged in KO mice on HS diet. Hydralazine, a PHD inhibitor, did not affect diuresis or natriuresis in LS diet-fed WT or KO mice but both were increased (p<0.05) in HS diet-fed WT mice. Hydralazine also increased UNOx V (p<0.05) with no change in diuresis, natriuresis, or HO-1 expression in KO mice on HS diet. CONCLUSIONS These data suggest that HS-induced PPARα-mediated downregulation of PHD1 is a novel pathway for PHD/HIF-1α transcriptional regulation for adaptive responses to promote renal function via downstream signaling involving NOS and HO.
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Affiliation(s)
- Ezinne Ozurumba
- Center for Cardiovascular Diseases, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX, USA
| | - Omana Mathew
- Center for Cardiovascular Diseases, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX, USA
| | - Katsuri Ranganna
- Center for Cardiovascular Diseases, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX, USA
| | - Myung Choi
- Center for Cardiovascular Diseases, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX, USA
| | - Adebayo Oyekan
- Center for Cardiovascular Diseases, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA, Phone: +(713) 313 4258/4341, Fax: +(713) 313 4342
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Chou CL, Hwang G, Hageman DJ, Han L, Agrawal P, Pisitkun T, Knepper MA. Identification of UT-A1- and AQP2-interacting proteins in rat inner medullary collecting duct. Am J Physiol Cell Physiol 2018; 314:C99-C117. [PMID: 29046292 PMCID: PMC5866378 DOI: 10.1152/ajpcell.00082.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 10/13/2017] [Accepted: 10/13/2017] [Indexed: 11/22/2022]
Abstract
The urea channel UT-A1 and the water channel aquaporin-2 (AQP2) mediate vasopressin-regulated transport in the renal inner medullary collecting duct (IMCD). To identify the proteins that interact with UT-A1 and AQP2 in native rat IMCD cells, we carried out chemical cross-linking followed by detergent solubilization, immunoprecipitation, and LC-MS/MS analysis of the immunoprecipitated material. The analyses revealed 133 UT-A1-interacting proteins and 139 AQP2-interacting proteins, each identified in multiple replicates. Fifty-three proteins that were present in both the UT-A1 and the AQP2 interactomes can be considered as mediators of housekeeping interactions, likely common to all plasma membrane proteins. Among proteins unique to the UT-A1 list were those involved in posttranslational modifications: phosphorylation (protein kinases Cdc42bpb, Phkb, Camk2d, and Mtor), ubiquitylation/deubiquitylation (Uba1, Usp9x), and neddylation (Nae1 and Uba3). Among the proteins unique to the AQP2 list were several Rab proteins (Rab1a, Rab2a, Rab5b, Rab5c, Rab7a, Rab11a, Rab11b, Rab14, Rab17) involved in membrane trafficking. UT-A1 was found to interact with UT-A3, although quantitative proteomics revealed that most UT-A1 molecules in the cell are not bound to UT-A3. In vitro incubation of UT-A1 peptides with the protein kinases identified in the UT-A1 interactome revealed that all except Mtor were capable of phosphorylating known sites in UT-A1. Overall, the UT-A1 and AQP2 interactomes provide a snapshot of a dynamic process in which UT-A1 and AQP2 are produced in the rough endoplasmic reticulum, processed through the Golgi apparatus, delivered to endosomes that move into and out of the plasma membrane, and are regulated in the plasma membrane.
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Affiliation(s)
- Chung-Lin Chou
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Gloria Hwang
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Daniel J Hageman
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Lichy Han
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Prashasti Agrawal
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
| | - Trairak Pisitkun
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
- Faculty of Medicine, Chulalongkorn University , Bangkok , Thailand
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, National Institutes of Health , Bethesda, Maryland
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Stridh S, Palm F, Takahashi T, Ikegami-Kawai M, Friederich-Persson M, Hansell P. Hyaluronan Production by Renomedullary Interstitial Cells: Influence of Endothelin, Angiotensin II and Vasopressin. Int J Mol Sci 2017; 18:ijms18122701. [PMID: 29236055 PMCID: PMC5751302 DOI: 10.3390/ijms18122701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/05/2017] [Accepted: 12/10/2017] [Indexed: 11/17/2022] Open
Abstract
The content of hyaluronan (HA) in the interstitium of the renal medulla changes in relation to body hydration status. We investigated if hormones of central importance for body fluid homeostasis affect HA production by renomedullary interstitial cells in culture (RMICs). Simultaneous treatment with vasopressin and angiotensin II (Ang II) reduced HA by 69%. No change occurred in the mRNA expressions of hyaluronan synthase 2 (HAS2) or hyaluronidases (Hyals), while Hyal activity in the supernatant increased by 67% and CD44 expression reduced by 42%. The autocoid endothelin (ET-1) at low concentrations (10−10 and 10−8 M) increased HA 3-fold. On the contrary, at a high concentration (10−6 M) ET-1 reduced HA by 47%. The ET-A receptor antagonist BQ123 not only reversed the reducing effect of high ET-1 on HA, but elevated it to the same level as low concentration ET-1, suggesting separate regulating roles for ET-A and ET-B receptors. This was corroborated by the addition of ET-B receptor antagonist BQ788 to low concentration ET-1, which abolished the HA increase. HAS2 and Hyal2 mRNA did not alter, while Hyal1 mRNA was increased at all ET-1 concentrations tested. Hyal activity was elevated the most by high ET-1 concentration, and blockade of ET-A receptors by BQ123 prevented about 30% of this response. The present study demonstrates an important regulatory influence of hormones involved in body fluid balance on HA handling by RMICs, thereby supporting the concept of a dynamic involvement of interstitial HA in renal fluid handling.
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Affiliation(s)
- Sara Stridh
- Department of Medical Cell Biology, Uppsala University, Biomedical Center, SE-75123 Uppsala, Sweden; (S.S.); (F.P.); (M.F.-P.)
- Department of Health Sciences, Red Cross University College, SE-14152 Stockholm, Sweden
| | - Fredrik Palm
- Department of Medical Cell Biology, Uppsala University, Biomedical Center, SE-75123 Uppsala, Sweden; (S.S.); (F.P.); (M.F.-P.)
| | - Tomoko Takahashi
- Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo 142-8501, Japan; (T.T.); (M.I.-K.)
| | - Mayumi Ikegami-Kawai
- Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo 142-8501, Japan; (T.T.); (M.I.-K.)
| | - Malou Friederich-Persson
- Department of Medical Cell Biology, Uppsala University, Biomedical Center, SE-75123 Uppsala, Sweden; (S.S.); (F.P.); (M.F.-P.)
| | - Peter Hansell
- Department of Medical Cell Biology, Uppsala University, Biomedical Center, SE-75123 Uppsala, Sweden; (S.S.); (F.P.); (M.F.-P.)
- Correspondence: ; Tel.: +46-184-714-130
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Arystarkhova E, Bouley R, Liu YB, Sweadner KJ. Impaired AQP2 trafficking in Fxyd1 knockout mice: A role for FXYD1 in regulated vesicular transport. PLoS One 2017; 12:e0188006. [PMID: 29155857 PMCID: PMC5695786 DOI: 10.1371/journal.pone.0188006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/30/2017] [Indexed: 01/08/2023] Open
Abstract
The final adjustment of urine volume occurs in the inner medullary collecting duct (IMCD), chiefly mediated by the water channel aquaporin 2 (AQP2). With vasopressin stimulation, AQP2 accumulation in the apical plasma membrane of principal cells allows water reabsorption from the lumen. We report that FXYD1 (phospholemman), better known as a regulator of Na,K-ATPase, has a role in AQP2 trafficking. Daytime urine of Fxyd1 knockout mice was more dilute than WT despite similar serum vasopressin, but both genotypes could concentrate urine during water deprivation. FXYD1 was found in IMCD. In WT mice, phosphorylated FXYD1 was detected intracellularly, and vasopressin induced its dephosphorylation. We tested the hypothesis that the dilute urine in knockouts was caused by alteration of AQP2 trafficking. In WT mice at baseline, FXYD1 and AQP2 were not strongly co-localized, but elevation of vasopressin produced translocation of both FXYD1 and AQP2 to the apical plasma membrane. In kidney slices, baseline AQP2 distribution was more scattered in the Fxyd1 knockout than in WT. Apical recruitment of AQP2 occurred in vasopressin-treated Fxyd1 knockout slices, but upon vasopressin washout, there was more rapid reversal of apical AQP2 localization and more heterogeneous cytoplasmic distribution of AQP2. Notably, in sucrose gradients, AQP2 was present in a detergent-resistant membrane domain that had lower sedimentation density in the knockout than in WT, and vasopressin treatment normalized its density. We propose that FXYD1 plays a role in regulating AQP2 retention in apical membrane, and that this involves transfers between raft-like membrane domains in endosomes and plasma membranes.
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Affiliation(s)
- Elena Arystarkhova
- Laboratory of Membrane Biology, Dept. of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, Unites States of America
- * E-mail: (EA); (KJS)
| | - Richard Bouley
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yi Bessie Liu
- Laboratory of Membrane Biology, Dept. of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, Unites States of America
| | - Kathleen J. Sweadner
- Laboratory of Membrane Biology, Dept. of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, Unites States of America
- * E-mail: (EA); (KJS)
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Chen Y, Fry BC, Layton AT. Modeling glucose metabolism and lactate production in the kidney. Math Biosci 2017; 289:116-129. [PMID: 28495544 PMCID: PMC5533195 DOI: 10.1016/j.mbs.2017.04.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 04/21/2017] [Accepted: 04/26/2017] [Indexed: 01/18/2023]
Abstract
The metabolism of glucose provides most of the ATP required for energy-dependent transport processes. In the inner medulla of the mammalian kidney, limited blood flow and O2 supply yield low oxygen tension; therefore, a substantial fraction of the glucose metabolism in that region is anaerobic. Lactate is considered to be a waste product of anaerobic glycolysis, which yields two lactate molecules for each glucose molecule consumed, thereby likely leading to the production and accumulation of a significant amount of lactate in the inner medulla. To gain insights into the transport and metabolic processes in the kidney, we have developed a detailed mathematical model of the renal medulla of the rat kidney. The model represents the radial organization of the renal tubules and vessels, which centers around the vascular bundles in the outer medulla and around clusters of collecting ducts in the inner medulla. Model simulations yield significant radial gradients in interstitial fluid oxygen tension and glucose and lactate concentrations in the outer medulla and upper inner medulla. In the deep inner medulla, interstitial fluid concentrations become much more homogeneous, as the radial organization of tubules and vessels is not distinguishable. Using this model, we have identified parameters concerning glucose transport and basal metabolism, as well as lactate production via anaerobic glycolysis, that yield predicted blood glucose and lactate concentrations consistent with experimental measurements in the papillary tip. In addition, simulations indicate that the radial organization of the rat kidney may affect lactate buildup in the inner medulla.
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Affiliation(s)
- Ying Chen
- Department of Mathematics, Duke University, Durham, NC, United States
| | - Brendan C Fry
- Department of Mathematical and Computer Sciences, Metropolitan State University of Denver, Denver, CO, United States
| | - Anita T Layton
- Department of Mathematics, Duke University, Durham, NC, United States.
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Abstract
It has long been viewed that the maintenance of osmotic balance in response to high salt intake is a passive process that is mediated largely by increased water consumption to balance the salt load. Two studies in this issue of the JCI challenge this notion and demonstrate that osmotic balance in response to high salt intake involves a complex regulatory process that is influenced by hormone fluctuation, metabolism, food consumption, water intake, and renal salt and water excretion. Rakova et al. report the unexpected observation that long-term high salt intake did not increase water consumption in humans but instead increased water retention. Moreover, salt and water balance was influenced by glucocorticoid and mineralocorticoid fluctuations. Kitada et al. extend upon these findings in mouse models and determined that increased urea and a corresponding increase in urea transporters in the renal medulla as the result of increased protein intake promote the water retention that is needed to achieve osmotic homeostasis. Together, the results of these two studies lay the groundwork for future studies to determine how, in the face of chronic changes in salt intake, humans maintain volume and osmotic homeostasis.
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Zhu M, Zeng F, Cui Y, Liu X, Chen H. [Expression of matrix Gla protein and bone morphogenetic protein 2 in renal papillary tissues in patients with calcium oxalate kidney stones]. Zhong Nan Da Xue Xue Bao Yi Xue Ban 2017; 42:277-283. [PMID: 28364100 DOI: 10.11817/j.issn.1672-7347.2017.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To compare expression levels of matrix Gla protein (MGP) and bone morphogenetic protein 2 (BMP-2) in Randall's plaque of renal papillary tissues in patients with calcium oxalate kidney stones and the underlying mechanism for stone formation.
Methods: A total of 30 samples of Randall's plaque in renal papillary tissues from patients with calcium oxalate kidney stones were collected from the Department of Urology of Xiangya Hospital of Central South University from April, 2015 to December, 2015 and served as an experimental group. Ten samples of renal papillary tissues in patients undergone renal tumor nephrectomy were collected from the same hospital and served as a control group. The expressions of MGP and BMP-2 mRNA and protein were detected by quantitative real-time PCR and Western blot.Meanwhile, immunohistochemical technique was used to observe the expressions of MGP and BMP-2 in different parts of renal papillary tissues in the 2 groups.
Results: 1) The mRNA expression levels of MGP in the experimental group and the control group were 0.760±0.804 and 1.365±0.348, respectively, with significant difference between them (P<0.05). Them RNA levels of BMP-2 in the experimental group and the control group were 2.500±0.725 and 1.485±0.870, respectively, with significant difference between them (P<0.05). The expression levels of MGP protein in the experimental group and the control group were 0.130±0.424 and 0.202±0.704, respectively, with no significant difference between them (P>0.05). The expression levels of BMP-2 protein in the experimental group and the control group were 0.885±0.220 and 0.682±0.272, respectively, with significant difference between them (P<0.05). The immunohistochemistry showed that the protein expression of MGP in the experimental group was lower than that in the control group, while the protein expression of BMP-2 in the experimental group was higher than that in the control group (both P<0.05).
Conclusion: The BMP-2 expression is increased while MGP expression is decreased in renal papillary tissues in patients with calcium oxalate kidney stones, and the formation of calcium oxalate kidney stone might be a kind of osteogenetic reaction or ectopic calcification.
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Affiliation(s)
- Min Zhu
- Department of Urology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Feng Zeng
- Department of Urology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yu Cui
- Department of Urology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Xifeng Liu
- Department of Urology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Hequn Chen
- Department of Urology, Xiangya Hospital, Central South University, Changsha 410008, China
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Lin Q, Geng Y, Zhao M, Lin S, Zhu Q, Tian Z. MiR-21 Regulates TNF-α-Induced CD40 Expression via the SIRT1-NF-κB Pathway in Renal Inner Medullary Collecting Duct Cells. Cell Physiol Biochem 2017; 41:124-136. [PMID: 28214900 DOI: 10.1159/000455981] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/22/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Recent studies have indicated that microRNA-21 (miR-21) is involved in the inflammatory response in relation to renal disease. Sirtuin1 (SIRT1) exerts renoprotective properties by counteracting inflammation. The activation of CD40 triggers inflammation that participates in renal inflammation and injury. The relationship between miR-21, SIRT1 and CD40, however, remains elusive. METHODS Immunohistochemistry, small-interfering RNA (siRNA) transfection, quantitative real-time PCR and western blotting were applied to assess the morphological, functional and molecular mechanisms in primary cultured renal inner medullary collecting duct (IMCD) cells. RESULTS TNF-α induced miR-21, CD40 and acetylated-NF-κBp65 (Ac-p65) expressions and reduced SIRT1 expression in IMCD cells. miR-21 mimics increased SIRT1 expression and attenuated Ac-p65 and CD40 expressions in TNF-α-induced IMCD cells, and the corresponding changes were observed with a miR-21 inhibitor. SIRT1 overexpression or activation by SRT1720 diminished TNF-α-induced CD40 and Ac-p65 expressions, which was reversed by SIRT1 siRNA or the inhibitors Ex527 and sirtinol and augmented by pretreatment with NF-κB siRNA. Further study found that the inhibitory effect of miR-21 on Ac-p65 and CD40 expressions was impeded by pretreatment with SIRT1 siRNA. CONCLUSION The present study indicates that miR-21 inhibits TNF-α-induced CD40 expression in IMCD cells via the SIRT1-NF-κB signalling pathway, which provides new insight in understanding the anti-inflammatory effect of miR-21.
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Ren H, Yang B, Ruiz JA, Efe O, Ilori TO, Sands JM, Klein JD. Phosphatase inhibition increases AQP2 accumulation in the rat IMCD apical plasma membrane. Am J Physiol Renal Physiol 2016; 311:F1189-F1197. [PMID: 27488997 PMCID: PMC5210195 DOI: 10.1152/ajprenal.00150.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 08/01/2016] [Indexed: 01/11/2023] Open
Abstract
Vasopressin triggers the phosphorylation and apical plasma membrane accumulation of aquaporin 2 (AQP2), and it plays an essential role in urine concentration. Vasopressin, acting through protein kinase A, phosphorylates AQP2. However, the phosphorylation state of AQP2 could also be affected by the action of protein phosphatases (PPs). Rat inner medullas (IM) were incubated with calyculin (PP1 and PP2A inhibitor, 50 nM) or tacrolimus (PP2B inhibitor, 100 nM). Calyculin did not affect total AQP2 protein abundance (by Western blot) but did significantly increase the abundances of pS256-AQP2 and pS264-AQP2. It did not change pS261-AQP2 or pS269-AQP2. Calyculin significantly enhanced the membrane accumulation (by biotinylation) of total AQP2, pS256-AQP2, and pS264-AQP2. Likewise, immunohistochemistry showed an increase in the apical plasma membrane association of pS256-AQP2 and pS264-AQP2 in calyculin-treated rat IM. Tacrolimus also did not change total AQP2 abundance but significantly increased the abundances of pS261-AQP2 and pS264-AQP2. In contrast to calyculin, tacrolimus did not change the amount of total AQP2 in the plasma membrane (by biotinylation and immunohistochemistry). Tacrolimus did increase the expression of pS264-AQP2 in the apical plasma membrane (by immunohistochemistry). In conclusion, PP1/PP2A regulates the phosphorylation and apical plasma membrane accumulation of AQP2 differently than PP2B. Serine-264 of AQP2 is a phosphorylation site that is regulated by both PP1/PP2A and PP2B. This dual regulatory pathway may suggest a previously unappreciated role for multiple phosphatases in the regulation of urine concentration.
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Affiliation(s)
- Huiwen Ren
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
- Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China; and
| | - Baoxue Yang
- Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China; and
| | - Joseph A Ruiz
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
| | - Orhan Efe
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
| | - Titilayo O Ilori
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
| | - Jeff M Sands
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
| | - Janet D Klein
- Department of Medicine, Renal Division, Emory University School of Medicine, Atlanta, Georgia;
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia
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Song K, Stuart D, Abraham N, Wang F, Wang S, Yang T, Sigmund CD, Kohan DE, Ramkumar N. Collecting Duct Renin Does Not Mediate DOCA-Salt Hypertension or Renal Injury. PLoS One 2016; 11:e0159872. [PMID: 27467376 PMCID: PMC4965005 DOI: 10.1371/journal.pone.0159872] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/08/2016] [Indexed: 01/09/2023] Open
Abstract
Collecting duct (CD)-derived renin is involved in the hypertensive response to chronic angiotensin-II (Ang-II) administration. However, whether CD renin is involved in Ang-II independent hypertension is currently unknown. To begin to examine this, 12 week old male and female CD-specific renin knock out (KO) mice and their littermate controls were subjected to uni-nephrectomy followed by 2 weeks of deoxycorticosterone acetate (DOCA) infusion combined with a high salt diet. Radiotelemetric blood pressure (BP) was similar between KO and control mice at baseline; BP increased in both groups to a similar degree throughout the 2 weeks of DOCA-salt treatment. Urinary albumin excretion and plasma blood urea nitrogen were comparable between the two groups after DOCA-salt treatment. Fibrosis as assessed by Masson’s Trichrome stain/Sirius Red stain and collagen-1 mRNA expression was similar between control and KO mice. Compared to baseline, DOCA-salt treatment decreased plasma renin concentration (PRC), urinary renin excretion and medullary renin mRNA expression in both floxed and CD renin KO mice with no detectable differences between the two groups. Further, in primary culture of rat inner medullary CD, aldosterone treatment did not change renin activity or total renin content. Taken together, these data suggest that CD derived renin does not play a role in DOCA-salt hypertension.
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Affiliation(s)
- Kai Song
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- Department of Nephrology, Second Affiliated Hospital of Soochow University, Soochow City, China
| | - Deborah Stuart
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Nikita Abraham
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Fei Wang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Shuping Wang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
| | - Tianxin Yang
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
| | - Curt D. Sigmund
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Donald E. Kohan
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah, United States of America
| | - Nirupama Ramkumar
- Division of Nephrology and Hypertension, University of Utah Health Sciences Center, Salt Lake City, Utah, United States of America
- * E-mail:
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Qian X, Sands JM, Song X, Chen G. Modulation of kidney urea transporter UT-A3 activity by alpha2,6-sialylation. Pflugers Arch 2016; 468:1161-1170. [PMID: 26972907 PMCID: PMC4945389 DOI: 10.1007/s00424-016-1802-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 02/16/2016] [Accepted: 02/23/2016] [Indexed: 10/22/2022]
Abstract
Two urea transporters, UT-A1 and UT-A3, are expressed in the kidney terminal inner medullary collecting duct (IMCD) and are important for the production of concentrated urine. UT-A1, as the largest isoform of all UT-A urea transporters, has gained much attention and been extensively studied; however, the role and the regulation of UT-A3 are less explored. In this study, we investigated UT-A3 regulation by glycosylation modification. A site-directed mutagenesis verified a single glycosylation site in UT-A3 at Asn279. Loss of the glycosylation reduced forskolin-stimulated UT-A3 cell membrane expression and urea transport activity. UT-A3 has two glycosylation forms, 45 and 65 kDa. Using sugar-specific binding lectins, the UT-A3 glycosylation profile was examined. The 45-kDa form was pulled down by lectin concanavalin A (Con A) and Galant husnivalis lectin (GNL), indicating an immature glycan with a high amount of mannose (Man), whereas the 65-kDa form is a mature glycan composed of acetylglucosamine (GlcNAc) and poly-N-acetyllactosame (poly-LacNAc) that was pulled down by wheat germ agglutinin (WGA) and tomato lectin, respectively. Interestingly, the mature form of UT-A3 glycan contains significant amounts of sialic acid. We explored the enzymes responsible for directing UT-A3 sialylation. Sialyltransferase ST6GalI, but not ST3GalIV, catabolizes UT-A3 α2,6-sialylation. Activation of protein kinase C (PKC) by PDB treatment promoted UT-A3 glycan sialylation and membrane surface expression. The PKC inhibitor chelerythrine blocks ST6GalI-induced UT-A3 sialylation. Increased sialylation by ST6GalI increased UT-A3 protein stability and urea transport activity. Collectively, our study reveals a novel mechanism of UT-A3 regulation by ST6GalI-mediated sialylation modification that may play an important role in kidney urea reabsorption and the urinary concentrating mechanism.
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Affiliation(s)
- Xiaoqian Qian
- Department of Physiology, Emory University, Atlanta, GA 30322, USA
- Cardiovascular Center, the 4 affiliated hospital, Harbin Medical University, Heilongjiang 150001, China
| | - Jeff M. Sands
- Department of Physiology, Emory University, Atlanta, GA 30322, USA
- Renal Division, Department of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Xiang Song
- Cardiovascular Center, the 4 affiliated hospital, Harbin Medical University, Heilongjiang 150001, China
| | - Guangping Chen
- Department of Physiology, Emory University, Atlanta, GA 30322, USA
- Renal Division, Department of Medicine, Emory University, Atlanta, GA 30322, USA
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Kim WY, Lee HW, Han KH, Nam SA, Choi A, Kim YK, Kim J. Descending thin limb of the intermediate loop expresses both aquaporin 1 and urea transporter A2 in the mouse kidney. Histochem Cell Biol 2016; 146:1-12. [PMID: 27091563 DOI: 10.1007/s00418-016-1434-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2016] [Indexed: 10/21/2022]
Abstract
A new intermediate type of Henle's loop has been reported that it extends into the inner medulla and turns within the first millimeter beyond the outer medulla. This study aimed to identify the descending thin limb (DTL) of the intermediate loop in the adult C57Bl/6 mouse kidney using aquaporin 1 (AQP1) and urea transporter A2 (UT-A2) antibodies. In the upper part of the inner stripe of the outer medulla (ISOM), AQP1 was expressed strongly in the DTL with type II epithelium of the long loop, but not in type I epithelium of the short loop. The DTL of the intermediate loop exhibited weak AQP1 immunoreactivity. UT-A2 immunoreactivity was not observed in the upper part of any DTL type. AQP1 expression was similar in the upper and middle parts of the ISOM. UT-A2 expression was variable, being expressed strongly in the DTL with type I epithelium of the short loop, but not in type II epithelium of the long loop. In the innermost part of the ISOM, AQP1 was expressed only in type III epithelium of the long loop. UT-A2-positive and UT-A2-negative cells were intermingled in type I epithelium of the intermediate loop, but were not observed in type III epithelium of the long loop. UT-A2-positive DTLs of the intermediate loop extended into the UT-A2/AQP1-negative type I epithelium in the initial part of the inner medulla. These results demonstrate that the DTL of the intermediate loop is composed of type I epithelium and expresses both AQP1 and UT-A2. The functional role of the DTL of the intermediate loop may be distinct from the short or long loops.
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Affiliation(s)
- Wan-Young Kim
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505, Banpo-Dong, Seocho-Ku, Seoul, 137-701, Korea
| | - Hyun-Wook Lee
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505, Banpo-Dong, Seocho-Ku, Seoul, 137-701, Korea
| | - Ki-Hwan Han
- Department of Anatomy, Ewha Womans University School of Medicine, Seoul, Korea
| | - Sun-Ah Nam
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505, Banpo-Dong, Seocho-Ku, Seoul, 137-701, Korea
| | - Arum Choi
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505, Banpo-Dong, Seocho-Ku, Seoul, 137-701, Korea
| | - Yong-Kyun Kim
- Department of Internal Medicine and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jin Kim
- Department of Anatomy and Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505, Banpo-Dong, Seocho-Ku, Seoul, 137-701, Korea.
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Li YX, Huang Y, Liu S, Mao Y, Yuan CY, Yang X, Yao LJ. Glycogen Synthase Kinase-3 Modulates Hyperosmotic-Induced Urea Transporter A1 Relocation in the Inner Medullary Collecting Duct Cells. Nephron Clin Pract 2016; 133:71-9. [PMID: 27161213 DOI: 10.1159/000446158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 03/28/2016] [Indexed: 11/19/2022] Open
Abstract
AIM Glycogen synthase kinase 3 (GSK3) regulates urine concentration by mediating the vasopressin-induced aquaporin 2 expression and water permeability, although it is unknown whether GSK3 also mediates the accumulation of the urea transporter A1 (UT-A1). The aim of this study is to investigate the effect of GSK3 on UT-A1 distribution. METHODS Mouse inner medullary collecting duct 3 cells were transfected with UT-A1-GFP construct. The stable transfected cells were cultured under hypertonic conditions, treated with GSK3 inhibitor lithium chloride, GSK3 activator, lysosome or proteasome inhibitor. The expression levels of UT-A1, GSK3, and phospho-GSK3 were analyzed using western blot. The interaction between UT-A1 and the Golgi apparatus was examined using confocal immunofluorescence microscope. The UT-A1 trafficking was examined using the biotinylation of surface membranes. RESULTS UT-A1 dissociated away from the Golgi apparatus and translocated to the plasma membrane under hypertonic-NaCl and NaCl plus urea stimulation. This movement was accompanied by the increased phosphorylation of GSK3 and its localization on the cellular membrane. Moreover, these results were duplicated by treating the cells with the GSK3 inhibitor, and by contrast, were partially reversed by the GSK3 activator. Treating cells with a lysosome or proteasome inhibitor failed to attenuate the effects of hypertonic stimulus, indicating that the loss of UT-A1 from the Golgi was not due to degradation. CONCLUSION Our results suggest that GSK3 may in part modulate the hypertonic-induced intracellular UT-A1 redistribution and its accumulation on the plasma membrane, which may constitute another mechanism by which GSK3 modulates urine concentration.
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Affiliation(s)
- Yong-Xia Li
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
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Daryadel A, Bourgeois S, Figueiredo MFL, Gomes Moreira A, Kampik NB, Oberli L, Mohebbi N, Lu X, Meima ME, Danser AHJ, Wagner CA. Colocalization of the (Pro)renin Receptor/Atp6ap2 with H+-ATPases in Mouse Kidney but Prorenin Does Not Acutely Regulate Intercalated Cell H+-ATPase Activity. PLoS One 2016; 11:e0147831. [PMID: 26824839 PMCID: PMC4732657 DOI: 10.1371/journal.pone.0147831] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 01/08/2016] [Indexed: 12/11/2022] Open
Abstract
The (Pro)renin receptor (P)RR/Atp6ap2 is a cell surface protein capable of binding and non-proteolytically activate prorenin. Additionally, (P)RR is associated with H+-ATPases and alternative functions in H+-ATPase regulation as well as in Wnt signalling have been reported. Kidneys express very high levels of H+-ATPases which are involved in multiple functions such as endocytosis, membrane protein recycling as well as urinary acidification, bicarbonate reabsorption, and salt absorption. Here, we wanted to localize the (P)RR/Atp6ap2 along the murine nephron, exmaine whether the (P)RR/Atp6ap2 is coregulated with other H+-ATPase subunits, and whether acute stimulation of the (P)RR/Atp6ap2 with prorenin regulates H+-ATPase activity in intercalated cells in freshly isolated collecting ducts. We localized (P)PR/Atp6ap2 along the murine nephron by qPCR and immunohistochemistry. (P)RR/Atp6ap2 mRNA was detected in all nephron segments with highest levels in the collecting system coinciding with H+-ATPases. Further experiments demonstrated expression at the brush border membrane of proximal tubules and in all types of intercalated cells colocalizing with H+-ATPases. In mice treated with NH4Cl, NaHCO3, KHCO3, NaCl, or the mineralocorticoid DOCA for 7 days, (P)RR/Atp6ap2 and H+-ATPase subunits were regulated but not co-regulated at protein and mRNA levels. Immunolocalization in kidneys from control, NH4Cl or NaHCO3 treated mice demonstrated always colocalization of PRR/Atp6ap2 with H+-ATPase subunits at the brush border membrane of proximal tubules, the apical pole of type A intercalated cells, and at basolateral and/or apical membranes of non-type A intercalated cells. Microperfusion of isolated cortical collecting ducts and luminal application of prorenin did not acutely stimulate H+-ATPase activity. However, incubation of isolated collecting ducts with prorenin non-significantly increased ERK1/2 phosphorylation. Our results suggest that the PRR/Atp6ap2 may form a complex with H+-ATPases in proximal tubule and intercalated cells but that prorenin has no acute effect on H+-ATPase activity in intercalated cells.
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MESH Headings
- Ammonium Chloride/pharmacology
- Animals
- Anion Transport Proteins/genetics
- Anion Transport Proteins/metabolism
- Aquaporin 2/genetics
- Aquaporin 2/metabolism
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Dogs
- Gene Expression Regulation
- Kidney Cortex/cytology
- Kidney Cortex/drug effects
- Kidney Cortex/metabolism
- Kidney Medulla/cytology
- Kidney Medulla/drug effects
- Kidney Medulla/metabolism
- Kidney Tubules, Collecting/cytology
- Kidney Tubules, Collecting/drug effects
- Kidney Tubules, Collecting/metabolism
- Kidney Tubules, Proximal/cytology
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Madin Darby Canine Kidney Cells
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Inbred C57BL
- Proton-Translocating ATPases/genetics
- Proton-Translocating ATPases/metabolism
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Renin/pharmacology
- Renin-Angiotensin System/drug effects
- Signal Transduction
- Sodium Bicarbonate/pharmacology
- Sodium Chloride/pharmacology
- Sodium-Phosphate Cotransporter Proteins, Type IIa/genetics
- Sodium-Phosphate Cotransporter Proteins, Type IIa/metabolism
- Solute Carrier Family 12, Member 1/genetics
- Solute Carrier Family 12, Member 1/metabolism
- Solute Carrier Family 12, Member 3/genetics
- Solute Carrier Family 12, Member 3/metabolism
- Sulfate Transporters
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Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Soline Bourgeois
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | | | - Nicole B. Kampik
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Lisa Oberli
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Nilufar Mohebbi
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Divison of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Xifeng Lu
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marcel E. Meima
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - A. H. Jan Danser
- Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carsten A. Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- * E-mail:
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Khositseth S, Uawithya P, Somparn P, Charngkaew K, Thippamom N, Hoffert JD, Saeed F, Michael Payne D, Chen SH, Fenton RA, Pisitkun T. Autophagic degradation of aquaporin-2 is an early event in hypokalemia-induced nephrogenic diabetes insipidus. Sci Rep 2015; 5:18311. [PMID: 26674602 PMCID: PMC4682130 DOI: 10.1038/srep18311] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/16/2015] [Indexed: 12/19/2022] Open
Abstract
Hypokalemia (low serum potassium level) is a common electrolyte imbalance that can cause a defect in urinary concentrating ability, i.e., nephrogenic diabetes insipidus (NDI), but the molecular mechanism is unknown. We employed proteomic analysis of inner medullary collecting ducts (IMCD) from rats fed with a potassium-free diet for 1 day. IMCD protein quantification was performed by mass spectrometry using a label-free methodology. A total of 131 proteins, including the water channel AQP2, exhibited significant changes in abundance, most of which were decreased. Bioinformatic analysis revealed that many of the down-regulated proteins were associated with the biological processes of generation of precursor metabolites and energy, actin cytoskeleton organization, and cell-cell adhesion. Targeted LC-MS/MS and immunoblotting studies further confirmed the down regulation of 18 selected proteins. Electron microscopy showed autophagosomes/autophagolysosomes in the IMCD cells of rats deprived of potassium for only 1 day. An increased number of autophagosomes was also confirmed by immunofluorescence, demonstrating co-localization of LC3 and Lamp1 with AQP2 and several other down-regulated proteins in IMCD cells. AQP2 was also detected in autophagosomes in IMCD cells of potassium-deprived rats by immunogold electron microscopy. Thus, enhanced autophagic degradation of proteins, most notably including AQP2, is an early event in hypokalemia-induced NDI.
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Affiliation(s)
- Sookkasem Khositseth
- Department of Pediatrics, Faculty of Medicine, Thammasat University Klong Luang, Pathumthani, 12120, Thailand
| | - Panapat Uawithya
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 10700, Thailand
| | - Poorichaya Somparn
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Komgrid Charngkaew
- Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 10700, Thailand
| | - Nattakan Thippamom
- Department of Pediatrics, Faculty of Medicine, Thammasat University Klong Luang, Pathumthani, 12120, Thailand
| | - Jason D. Hoffert
- National Institute of Diabetes and Digestive and Kidney, Bethesda MD 20892, United States
| | - Fahad Saeed
- Department of Electrical & Computer Engineering and Department of Computer Science, Western Michigan University Kalamazoo, 49008, United States
| | - D. Michael Payne
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Shu-Hui Chen
- Department of Chemistry, National Cheng Kung University, Tainan City, 701, Taiwan
| | - Robert A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, 8000, Denmark
| | - Trairak Pisitkun
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, 8000, Denmark
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, Bethesda MD 20892, United States
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Nawata CM, Dantzler WH, Pannabecker TL. Alternative channels for urea in the inner medulla of the rat kidney. Am J Physiol Renal Physiol 2015; 309:F916-24. [PMID: 26423860 PMCID: PMC4669356 DOI: 10.1152/ajprenal.00392.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 09/24/2015] [Indexed: 11/22/2022] Open
Abstract
The ascending thin limbs (ATLs) and lower descending thin limbs (DTLs) of Henle's loop in the inner medulla of the rat are highly permeable to urea, and yet no urea transporters have been identified in these sections. We hypothesized that novel, yet-unidentified transporters in these tubule segments could explain the high urea permeability. cDNAs encoding for Na(+)-glucose transporter 1a (SGLT1a), Na(+)-glucose transporter 1 (NaGLT1), urea transporter (UT)-A2c, and UT-A2d were isolated and cloned from the Munich-Wistar rat inner medulla. SGLT1a is a novel NH2-terminal truncated variant of SGLT1. NaGLT1 is a Na(+)-dependent glucose transporter primarily located in the proximal tubules and not previously described in the thin limbs. UT-A2c and UT-A2d are novel variants of UT-A2. UT-A2c is truncated at the COOH terminus, and UT-A2d has one exon skipped. When rats underwent water restriction for 72 h, mRNA levels of SGLT1a increased in ATLs, NaGLT1 levels increased in both ATLs and DTLs, and UT-A2c increased in ATLs. [(14)C]urea uptake assays performed on Xenopus oocytes heterologously expressing these proteins revealed that despite having structural differences from their full-length versions, SGLT1a, UT-A2c, and UT-A2d enhanced urea uptake. NaGLT1 also facilitated urea uptake. Uptakes were Na(+) independent and inhibitable by phloretin and/or phloridzin. Our data indicate that there are several alternative channels for urea in the rat inner medulla that could potentially contribute to the high urea permeabilities in thin limb segments.
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Affiliation(s)
- C Michele Nawata
- Department of Physiology, University of Arizona Health Sciences Center, Tucson, Arizona
| | - William H Dantzler
- Department of Physiology, University of Arizona Health Sciences Center, Tucson, Arizona
| | - Thomas L Pannabecker
- Department of Physiology, University of Arizona Health Sciences Center, Tucson, Arizona
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López-González Z, Ayala-Aguilera C, Martinez-Morales F, Galicia-Cruz O, Salvador-Hernández C, Pedraza-Chaverri J, Medeiros M, Hernández AM, Escobar LI. Immunolocalization of hyperpolarization-activated cationic HCN1 and HCN3 channels in the rat nephron: regulation of HCN3 by potassium diets. Histochem Cell Biol 2015; 145:25-40. [PMID: 26515056 DOI: 10.1007/s00418-015-1375-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2015] [Indexed: 12/22/2022]
Abstract
Hyperpolarization-activated cationic and cyclic nucleotide-gated channels (HCN) comprise four homologous subunits (HCN1-HCN4). HCN channels are found in excitable and non-excitable tissues in mammals. We have previously shown that HCN2 may transport ammonium (NH4 (+)), besides sodium (Na(+)), in the rat distal nephron. In the present work, we identified HCN1 and HCN3 in the proximal tubule (PT) and HCN3 in the thick ascending limb of Henle (TALH) of the rat kidney. Immunoblot assays detected HCN1 (130 kDa) and HCN3 (90 KDa) and their truncated proteins C-terminal HCN1 (93 KDa) and N-terminal HCN3 (65 KDa) in enriched plasma membranes from cortex (CX) and outer medulla (OM), as well as in brush-border membrane vesicles. Immunofluorescence assays confirmed apical localization of HCN1 and HCN3 in the PT. HCN3 was also found at the basolateral membrane of TALH. We evaluated chronic changes in mineral dietary on HCN3 protein abundance. Animals were fed with three different diets: sodium-deficient (SD) diet, potassium-deficient (KD) diet, and high-potassium (HK) diet. Up-regulation of HCN3 was observed in OM by KD and in CX and OM by HK; the opposite effect occurred with the N-terminal truncated HCN3 in CX (KD) and OM (HK). SD diet did not produce any change. Since HCN channels activate with membrane hyperpolarization, our results suggest that HCN channels may play a role in the Na(+)-K(+)-ATPase activity, contributing to Na(+), K(+), and acid-base homeostasis in the rat kidney.
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Affiliation(s)
- Zinaeli López-González
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico, DF, México
| | - Cosete Ayala-Aguilera
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico, DF, México
| | - Flavio Martinez-Morales
- Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Othir Galicia-Cruz
- Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - Carolina Salvador-Hernández
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico, DF, México
| | - José Pedraza-Chaverri
- Departamento de Biología, Facultad de Química, Universidad Nacional Autónoma de México, México, DF, México
| | - Mara Medeiros
- Laboratorio de Investigación en Nefrología y Metabolismo Mineral Óseo, Hospital Infantil de México Federico Gómez, México, México
| | - Ana Maria Hernández
- Laboratorio de Investigación en Nefrología y Metabolismo Mineral Óseo, Hospital Infantil de México Federico Gómez, México, México
| | - Laura I Escobar
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, 04510, Mexico, DF, México.
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Plain A, Wulfmeyer VC, Milatz S, Klietz A, Hou J, Bleich M, Himmerkus N. Corticomedullary difference in the effects of dietary Ca²⁺ on tight junction properties in thick ascending limbs of Henle's loop. Pflugers Arch 2015; 468:293-303. [PMID: 26497703 DOI: 10.1007/s00424-015-1748-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 10/13/2015] [Accepted: 10/16/2015] [Indexed: 11/26/2022]
Abstract
The thick ascending limb of Henle's loop (TAL) drives an important part of the reabsorption of divalent cations. This reabsorption occurs via the paracellular pathway formed by the tight junction (TJ), which in the TAL shows cation selectivity. Claudins, a family of TJ proteins, determine the permeability and selectivity of this pathway. Mice were fed with normal or high-Ca(2+) diet, and effects on the reabsorptive properties of cortical and medullary TAL segments were analysed by tubule microdissection and microperfusion. Claudin expression was investigated by immunostaining and quantitative PCR. We show that the TAL adapted to high Ca(2+) load in a sub-segment-specific manner. In medullary TAL, transcellular NaCl transport was attenuated. The transepithelial voltage decreased from 10.9 ± 0.6 mV at control diet to 8.3 ± 0.5 mV at high Ca(2+) load, thereby reducing the driving force for Ca(2+) and Mg(2+) uptake. Cortical TAL showed a reduction in paracellular Ca(2+) and Mg(2+) permeabilities from 8.2 ± 0.7 to 6.2 ± 0.5 ∙ 10(-4) cm/s and from 4.8 ± 0.5 to 3.0 ± 0.2 · 10(-4) cm/s at control and high-Ca(2+) diet, respectively. Expression, localisation and regulation of claudins 10, 14, 16 and 19 differed along the corticomedullary axis: Towards the cortex, the main site of divalent cation reabsorption in TAL, high-Ca(2+) intake led to a strong upregulation of claudin-14 within TAL TJs while claudin-16 and -19 were unaltered. Towards the inner medulla, only claudin-10 was present in TAL TJ strands. In summary, high-Ca(2+) diet induced a reduction of divalent cation reabsorption via a diminution of NaCl transport and driving force in mTAL and via decreased paracellular permeabilities in cTAL. We reveal an important regulatory pattern along the corticomedullary axis and improve the understanding how the kidney disposes of detrimental excess Ca(2+).
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Affiliation(s)
- Allein Plain
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Vera C Wulfmeyer
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Susanne Milatz
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Adrian Klietz
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Jianghui Hou
- Washington University Renal Division, St. Louis, MO, USA
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany
| | - Nina Himmerkus
- Institute of Physiology, Christian-Albrechts-University Kiel, Olshausenstraße 40, Kiel, 24098, Germany.
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Schein V, Kucharski LC, Guerreiro PMG, Martins TL, Morgado I, Power DM, Canario AVM, da Silva RSM. Stanniocalcin 1 effects on the renal gluconeogenesis pathway in rat and fish. Mol Cell Endocrinol 2015; 414:1-8. [PMID: 26187698 DOI: 10.1016/j.mce.2015.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/03/2015] [Accepted: 07/10/2015] [Indexed: 11/16/2022]
Abstract
The mammalian kidney contributes significantly to glucose homeostasis through gluconeogenesis. Considering that stanniocalcin 1 (STC1) regulates ATP production, is synthesized and acts in different cell types of the nephron, the present study hypothesized that STC1 may be implicated in the regulation of gluconeogenesis in the vertebrate kidney. Human STC1 strongly reduced gluconeogenesis from (14)C-glutamine in rat renal medulla (MD) slices but not in renal cortex (CX), nor from (14)C-lactic acid. Total PEPCK activity was markedly reduced by hSTC1 in MD but not in CX. Pck2 (mitochondrial PEPCK isoform) was down-regulated by hSTC1 in MD but not in CX. In fish (Dicentrarchus labrax) kidney slices, both STC1-A and -B isoforms decreased gluconeogenesis from (14)C-acid lactic, while STC1-A increased gluconeogenesis from (14)C-glutamine. Overall, our results demonstrate a role for STC1 in the control of glucose synthesis via renal gluconeogenesis in mammals and suggest that it may have a similar role in teleost fishes.
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Affiliation(s)
- Vanessa Schein
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil; Pos-Graduate Program in Health Sciences, Department of Obstetrics and Gynecology, School of Medicine, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2400, 90035-003, Porto Alegre, RS, Brazil; CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal.
| | - Luiz C Kucharski
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil
| | - Pedro M G Guerreiro
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Tiago Leal Martins
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil
| | - Isabel Morgado
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Deborah M Power
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Adelino V M Canario
- CCMAR - Centre for Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139, Faro, Portugal
| | - Roselis S M da Silva
- Pos-Graduate Program in Biological Sciences, Department of Physiology, Institute of Health Sciences, Universidade Federal do Rio Grande do Sul, Rua Sarmento Leite, 500, 90050-170, Porto Alegre, RS, Brazil
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50
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Pointer MA, Eley S, Anderson L, Waters B, Royall B, Nichols S, Wells C. Differential Effect of Renal Cortical and Medullary Interstitial Fluid Calcium on Blood Pressure Regulation in Salt-Sensitive Hypertension. Am J Hypertens 2015; 28:1049-55. [PMID: 25552516 DOI: 10.1093/ajh/hpu255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 11/24/2014] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Hypercalciuria is a frequent characteristic of hypertension. In this report we extend our earlier studies investigating the role of renal interstitial fluid calcium (ISF(Ca))(2+) as a link between urinary calcium excretion and blood pressure in the Dahl salt-sensitive (DS) hypertensive model. METHODS Dahl salt-sensitive and salt-resistant (DR) rats were placed on control (0.45%) and high (8%) salt diets to determine if changes in renal cortical and medullary ISF(Ca)(2+)correlated with changes in urinary calcium excretion and blood pressure. RESULTS We observed that renal ISFCa(2+) was predicted by urinary calcium excretion (P < 0.05) in DS rats but not DR rats. Renal cortical ISF(Ca)(2+) was negatively associated with blood pressure (P < 0.03) while renal medullary ISF(Ca)(2+) was positively associated with blood pressure in DS rats (P < 0.04). In contrast, neither urinary calcium excretion nor renal ISF(Ca)(2+) was associated with blood pressure in the DR rats under the conditions of this study. CONCLUSION We interpret these findings to suggest that decreased renal cortical ISF(Ca)(2+) plays a role in the increase in blood pressure following a high salt diet in salt hypertension perhaps by mediating renal vasoconstriction; the role of medullary calcium remains to be fully understood. Further studies are needed to determine the mechanism of the altered renal ISF(Ca)(2+) and its role in blood pressure regulation.
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Affiliation(s)
- Mildred A Pointer
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA.
| | - Shaleka Eley
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA
| | - Lauren Anderson
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA
| | - Brittany Waters
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA
| | - Brittany Royall
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA
| | - Sheena Nichols
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA
| | - Candace Wells
- Julius L. Chambers Biomedical/Biotechnology Research Institute, North Carolina Central University, Durham, North Carolina, USA; Department of Biology; North Carolina Central University, Durham, North Carolina, USA
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