1
|
Kamianowska M, Rybi-Szumińska A, Kamianowska A, Maciejczyk M, Zubrzycka A, Nazarko J, Wasilewska A. Urinary Concentration of Renal Biomarkers in Healthy Term Neonates: Gender Differences in GST-pi Excretion. Med Sci Monit 2024; 30:e942819. [PMID: 38389296 PMCID: PMC10898192 DOI: 10.12659/msm.942819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 12/10/2023] [Indexed: 02/24/2024] Open
Abstract
BACKGROUND Serum creatinine, the criterion standard in assessment of renal function, is not reliable for the neonatal period because of its dependence on renal immaturity and maternal creatinine levels. Thus, it is important to study other biomarkers of renal function in neonates. The present study aimed to measure the urinary concentration of renal biomarkers: calbindin, clusterin, GST-pi (glutathione-S-transferase-alpha), KIM-1 (kidney injury molecule 1), MCP-1 (monocyte chemoattractant protein-1), and B2M (beta 2-microglobulin) in healthy term neonates. MATERIAL AND METHODS In the study, we included 80 healthy term neonates - 40 females and 40 males. We collected the neonates' urine on their first day of life. Urinary concentrations of calbindin, clusterin, KIM-1, MCP-1, and B2M were assessed using an immunoassay for kidney toxicology research. Because dilution of the urine affects the concentrations of urinary biomarkers, we normalized them to the concentration of urinary creatinine (Cr) and present them as biomarker/Cr ratios. RESULTS We obtained the following values of the assessed biomarker/Cr ratios (median [Q1-Q3]): calbindin/Cr.: 197.04 (56.25-595.17), KIM-1/Cr: 0.09 (0.04-0.18), MCP-1/Cr: 0.05 (0.02-0.14), B2M/Cr: 126.12 (19.03-342.48), GST-pi/Cr in boys: 1.28 (0.46-3.77), GST-pi/Cr in girls: 8.66 (2.51-27.82), clusterin/Cr: 4.55 (1.79-12.97) ng/mg Cr. CONCLUSIONS We showed the urinary levels of calbindin, clusterin, GST-pi, KIM-1, MCP-1, B2M in white, West Slavic, healthy term neonates. We found that in there is an association between female sex and a higher urinary GST-pi excretion, but urinary excretion of calbindin, clusterin, KIM-1, MCP-1, and B2M is sex-independent. The urinary levels of the assessed biomarkers do not depend on the method of delivery.
Collapse
Affiliation(s)
- Monika Kamianowska
- Department of Neonatology and Neonatal Intensive Care, Medical University of Białystok, Białystok, Poland
| | | | - Aleksandra Kamianowska
- Department of Pediatrics and Nephrology, Medical University of Białystok, Białystok, Poland
| | - Mateusz Maciejczyk
- Department of Hygiene, Epidemiology and Ergonomics, Medical University of Białystok, Białystok, Poland
| | - Anna Zubrzycka
- Department of Neonatology and Neonatal Intensive Care, Medical University of Białystok, Białystok, Poland
| | - Joanna Nazarko
- Department of Neonatology and Neonatal Intensive Care, Medical University of Białystok, Białystok, Poland
| | - Anna Wasilewska
- Department of Pediatrics and Nephrology, Medical University of Białystok, Białystok, Poland
| |
Collapse
|
2
|
Eisner D, Neher E, Taschenberger H, Smith G. Physiology of intracellular calcium buffering. Physiol Rev 2023; 103:2767-2845. [PMID: 37326298 DOI: 10.1152/physrev.00042.2022] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/08/2023] [Accepted: 06/11/2023] [Indexed: 06/17/2023] Open
Abstract
Calcium signaling underlies much of physiology. Almost all the Ca2+ in the cytoplasm is bound to buffers, with typically only ∼1% being freely ionized at resting levels in most cells. Physiological Ca2+ buffers include small molecules and proteins, and experimentally Ca2+ indicators will also buffer calcium. The chemistry of interactions between Ca2+ and buffers determines the extent and speed of Ca2+ binding. The physiological effects of Ca2+ buffers are determined by the kinetics with which they bind Ca2+ and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca2+, the Ca2+ concentration, and whether Ca2+ ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca2+ signals as well as changes of Ca2+ concentration in organelles. It can also facilitate Ca2+ diffusion inside the cell. Ca2+ buffering affects synaptic transmission, muscle contraction, Ca2+ transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation and tetanic contraction in skeletal muscle and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca2+ buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required.
Collapse
Affiliation(s)
- David Eisner
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Erwin Neher
- Membrane Biophysics Laboratory, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Godfrey Smith
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
3
|
The importance of kidney calcium handling in the homeostasis of extracellular fluid calcium. Pflugers Arch 2022; 474:885-900. [PMID: 35842482 DOI: 10.1007/s00424-022-02725-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/09/2022] [Accepted: 06/30/2022] [Indexed: 12/13/2022]
Abstract
Extracellular fluid calcium concentration must be maintained within a narrow range in order to sustain many biological functions, encompassing muscle contraction, blood coagulation, and bone and tooth mineralization. Blood calcium value is critically dependent on the ability of the renal tubule to reabsorb the adequate amount of filtered calcium. Tubular calcium reabsorption is carried out by various and complex mechanisms in 3 distinct segments: the proximal tubule, the cortical thick ascending limb of the loop of Henle, and the late distal convoluted/connecting tubule. In addition, calcium reabsorption is tightly controlled by many endocrine, paracrine, and autocrine factors, as well as by non-hormonal factors, in order to adapt the tubular handling of calcium to the metabolic requirements. The present review summarizes the current knowledge of the mechanisms and factors involved in calcium handling by the kidney and, ultimately, in extracellular calcium homeostasis. The review also highlights some of our gaps in understanding that need to be addressed in the future.
Collapse
|
4
|
Khattar V, Wang L, Peng JB. Calcium selective channel TRPV6: Structure, function, and implications in health and disease. Gene 2022; 817:146192. [PMID: 35031425 PMCID: PMC8950124 DOI: 10.1016/j.gene.2022.146192] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 12/20/2021] [Accepted: 01/07/2022] [Indexed: 12/14/2022]
Abstract
Calcium-selective channel TRPV6 (Transient Receptor Potential channel family, Vanilloid subfamily member 6) belongs to the TRP family of cation channels and plays critical roles in transcellular calcium (Ca2+) transport, reuptake of Ca2+ into cells, and maintaining a local low Ca2+ environment for certain biological processes. Recent crystal and cryo-electron microscopy-based structures of TRPV6 have revealed mechanistic insights on how the protein achieves Ca2+ selectivity, permeation, and inactivation by calmodulin. The TRPV6 protein is expressed in a range of epithelial tissues such as the intestine, kidney, placenta, epididymis, and exocrine glands such as the pancreas, prostate and salivary, sweat, and mammary glands. The TRPV6 gene is a direct transcriptional target of the active form of vitamin D and is efficiently regulated to meet the body's need for Ca2+ demand. In addition, TRPV6 is also regulated by the level of dietary Ca2+ and under physiological conditions such as pregnancy and lactation. Genetic models of loss of function in TRPV6 display hypercalciuria, decreased bone marrow density, deficient weight gain, reduced fertility, and in some cases alopecia. The models also reveal that the channel plays an indispensable role in maintaining maternal-fetal Ca2+ transport and low Ca2+ environment in the epididymal lumen that is critical for male fertility. Most recently, loss of function mutations in TRPV6 gene is linked to transient neonatal hyperparathyroidism and early onset chronic pancreatitis. TRPV6 is overexpressed in a wide range of human malignancies and its upregulation is strongly correlated to tumor aggressiveness, metastasis, and poor survival in selected cancers. This review summarizes the current state of knowledge on the expression, structure, biophysical properties, function, polymorphisms, and regulation of TRPV6. The aberrant expression, polymorphisms, and dysfunction of this protein linked to human diseases are also discussed.
Collapse
Affiliation(s)
- Vinayak Khattar
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Lingyun Wang
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ji-Bin Peng
- Division of Nephrology, Department of Medicine, Nephrology Research and Training Center, Department of Urology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| |
Collapse
|
5
|
Reyes JV, Medina PMB. Renal calcium and magnesium handling in Gitelman syndrome. Am J Transl Res 2022; 14:1-19. [PMID: 35173827 PMCID: PMC8829599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/24/2021] [Indexed: 06/14/2023]
Abstract
Gitelman syndrome (GS) is an autosomal recessive salt-losing tubulopathy caused by biallelic inactivating mutations in the SLC12A3 gene. This gene encodes the thiazide-sensitive sodium-chloride cotransporter (NCC) which is exclusively expressed in the distal convoluted tubules (DCT). GS patients classically present with hypokalemic metabolic alkalosis with hypocalciuria and hypomagnesemia. While hypokalemia and metabolic alkalosis are easily explained by effects of the genotypic defect in GS, the mechanisms by which hypomagnesemia and hypocalciuria develop in GS are poorly understood. In this review, we aim to achieve three major objectives. First, present a concise discussion about current understanding on physiologic calcium and magnesium handling in the DCT. Second, integrate expression data from studies on calciotropic and magnesiotropic proteins relevant to the GS disease state. Lastly, provide insights into the possible mechanisms of calcium-magnesium crosstalk relating to the co-occurrence of hypocalciuria and hypomagnesemia in GS models. Our analyses highlight specific areas of study that are valuable in elucidating possible molecular pathways of hypocalciuria and hypomagnesemia in GS.
Collapse
Affiliation(s)
- Jeremiah V Reyes
- Biological Models Laboratory, Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila Ermita, Manila 1000, Philippines
| | - Paul Mark B Medina
- Biological Models Laboratory, Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila Ermita, Manila 1000, Philippines
| |
Collapse
|
6
|
Ellison DH, Maeoka Y, McCormick JA. Molecular Mechanisms of Renal Magnesium Reabsorption. J Am Soc Nephrol 2021; 32:2125-2136. [PMID: 34045316 PMCID: PMC8729834 DOI: 10.1681/asn.2021010042] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/28/2021] [Accepted: 05/01/2021] [Indexed: 02/04/2023] Open
Abstract
Magnesium is an essential cofactor in many cellular processes, and aberrations in magnesium homeostasis can have life-threatening consequences. The kidney plays a central role in maintaining serum magnesium within a narrow range (0.70-1.10 mmol/L). Along the proximal tubule and thick ascending limb, magnesium reabsorption occurs via paracellular pathways. Members of the claudin family form the magnesium pores in these segments, and also regulate magnesium reabsorption by adjusting the transepithelial voltage that drives it. Along the distal convoluted tubule transcellular reabsorption via heteromeric TRPM6/7 channels predominates, although paracellular reabsorption may also occur. In this segment, the NaCl cotransporter plays a critical role in determining transcellular magnesium reabsorption. Although the general machinery involved in renal magnesium reabsorption has been identified by studying genetic forms of magnesium imbalance, the mechanisms regulating it are poorly understood. This review discusses pathways of renal magnesium reabsorption by different segments of the nephron, emphasizing newer findings that provide insight into regulatory process, and outlining critical unanswered questions.
Collapse
Affiliation(s)
- David H. Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon,Veterans Affairs Portland Healthcare System, Portland, Oregon
| | - Yujiro Maeoka
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - James A. McCormick
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| |
Collapse
|
7
|
Akbari Z, Reisi P, Torkaman-Boutorabi A, Farahmandfar M. Effect of Pentoxifylline on Apoptotic-Related Gene Expression Profile, Learning and Memory Impairment Induced by Systemic Lipopolysaccharide Administration in the Rat Hippocampus. Int J Prev Med 2020; 11:151. [PMID: 33209221 PMCID: PMC7643573 DOI: 10.4103/ijpvm.ijpvm_170_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/29/2019] [Indexed: 01/16/2023] Open
Abstract
Background: Inflammation is one of the effective factors, in the development of functional disorders of the nervous system. Pentoxifylline (PTX) has an inhibitory effect on inflammatory factors. Therefore the aim of this study was to evaluate the effect of PTX on learning, memory and expression of genes, involved in neuronal survival in the rat hippocampus, following systemic lipopolysaccharide (LPS) injection. Methods: Male rats were randomly divided into 5 groups of control, LPS and LPS + PTX, receiving doses of 10, 25 and 50 mg/kg of PTX, respectively. In LPS groups, LPS was injected (5 mg/kg; intraperitoneal), and after one week, rats received intraperitoneal PTX for 14 days, in the treatment groups. Learning and memory were evaluated by object location task (OLT) and novel object recognition (NOR). Then, the hippocampus was dissected in order to measure the expression of the associated genes. Results: The results showed that peripheral LPS injection caused significant damage (P < 0.01) to learning and memory with respect to controls, but PTX with doses of 10 and 50 mg/kg prevented these impairments. Results from reverse transcription polymerase chain reaction (RT-PCR) showed that LPS significantly increased the expression of Bax and TNF- α with respect to controls. PTX in the LPS + PTX group significantly increased the expression of Bcl-2, BAD and Caspase-3. Conclusions: Other than the increased Bcl-2 expression, PTX had no significant effect on the expression of other genes, therefore further studies are needed to find out how PTX improves the learning and memory impairments, following the peripheral inflammation.
Collapse
Affiliation(s)
- Zahra Akbari
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.,International Campuses, Tehran University of Medical Sciences, Tehran, Iran
| | - Parham Reisi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Anahita Torkaman-Boutorabi
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Farahmandfar
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.,Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
8
|
Maeoka Y, McCormick JA. NaCl cotransporter activity and Mg 2+ handling by the distal convoluted tubule. Am J Physiol Renal Physiol 2020; 319:F1043-F1053. [PMID: 33135481 DOI: 10.1152/ajprenal.00463.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The genetic disease Gitelman syndrome, knockout mice, and pharmacological blockade with thiazide diuretics have revealed that reduced activity of the NaCl cotransporter (NCC) promotes renal Mg2+ wasting. NCC is expressed along the distal convoluted tubule (DCT), and its activity determines Mg2+ entry into DCT cells through transient receptor potential channel subfamily M member 6 (TRPM6). Several other genetic forms of hypomagnesemia lower the drive for Mg2+ entry by inhibiting activity of basolateral Na+-K+-ATPase, and reduced NCC activity may do the same. Lower intracellular Mg2+ may promote further Mg2+ loss by directly decreasing activity of Na+-K+-ATPase. Lower intracellular Mg2+ may also lower Na+-K+-ATPase indirectly by downregulating NCC. Lower NCC activity also induces atrophy of DCT cells, decreasing the available number of TRPM6 channels. Conversely, a mouse model with increased NCC activity was recently shown to display normal Mg2+ handling. Moreover, recent studies have identified calcineurin and uromodulin (UMOD) as regulators of both NCC and Mg2+ handling by the DCT. Calcineurin inhibitors paradoxically cause hypomagnesemia in a state of NCC activation, but this may be related to direct effects on TRPM6 gene expression. In Umod-/- mice, the cause of hypomagnesemia may be partly due to both decreased NCC expression and lower TRPM6 expression on the cell surface. This mini-review discusses these new findings and the possible role of altered Na+ flux through NCC and ultimately Na+-K+-ATPase in Mg2+ reabsorption by the DCT.
Collapse
Affiliation(s)
- Yujiro Maeoka
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| | - James A McCormick
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon
| |
Collapse
|
9
|
Watanabe H, Paxton RL, Tolerico MR, Nagalakshmi VK, Tanaka S, Okusa MD, Goto S, Narita I, Watanabe S, Sequeira-Lοpez MLS, Gomez RA. Expression of Acsm2, a kidney-specific gene, parallels the function and maturation of proximal tubular cells. Am J Physiol Renal Physiol 2020; 319:F603-F611. [PMID: 32830538 DOI: 10.1152/ajprenal.00348.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The acyl-CoA synthetase medium-chain family member 2 (Acsm2) gene was first identified and cloned by our group as a kidney-specific "KS" gene. However, its expression pattern and function remain to be clarified. In the present study, we found that the Acsm2 gene was expressed specifically and at a high level in normal adult kidneys. Expression of Acsm2 in kidneys followed a maturational pattern: it was low in newborn mice and increased with kidney development and maturation. In situ hybridization and immunohistochemistry revealed that Acsm2 was expressed specifically in proximal tubular cells of adult kidneys. Data from the Encyclopedia of DNA Elements database revealed that the Acsm2 gene locus in the mouse has specific histone modifications related to the active transcription of the gene exclusively in kidney cells. Following acute kidney injury, partial unilateral ureteral obstruction, and chronic kidney diseases, expression of Acsm2 in the proximal tubules was significantly decreased. In human samples, the expression pattern of ACSM2A, a homolog of mouse Acsm2, was similar to that in mice, and its expression decreased with several types of renal injuries. These results indicate that the expression of Acsm2 parallels the structural and functional maturation of proximal tubular cells. Downregulation of its expression in several models of kidney disease suggests that Acms2 may serve as a novel marker of proximal tubular injury and/or dysfunction.
Collapse
Affiliation(s)
- Hirofumi Watanabe
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Robert L Paxton
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Matthew R Tolerico
- Department of Biology, University of Virginia, Charlottesville, Virginia
| | - Vidya K Nagalakshmi
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Shinji Tanaka
- Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia
| | - Mark D Okusa
- Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia
| | - Shin Goto
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Seiji Watanabe
- Department of Pediatrics, Izu Medical and Welfare Center, Shizuoka, Japan
| | - Maria Luisa S Sequeira-Lοpez
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - R Ariel Gomez
- Department of Pediatrics, Child Health Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| |
Collapse
|
10
|
Martins JR, Haenni D, Bugarski M, Figurek A, Hall AM. Quantitative intravital Ca2+ imaging maps single cell behavior to kidney tubular structure. Am J Physiol Renal Physiol 2020; 319:F245-F255. [DOI: 10.1152/ajprenal.00052.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ca2+ is an important second messenger that translates extracellular stimuli into intracellular responses. Although there has been significant progress in understanding Ca2+ dynamics in organs such as the brain, the nature of Ca2+ signals in the kidney is still poorly understood. Here, we show that by using a genetically expressed highly sensitive reporter (GCaMP6s), it is possible to perform imaging of Ca2+ signals at high resolution in the mouse kidney in vivo. Moreover, by applying machine learning-based automated analysis using a Ca2+-independent signal, quantitative data can be extracted in an unbiased manner. By projecting the resulting data onto the structure of the kidney, we show that different tubular segments display highly distinct spatiotemporal patterns of Ca2+ signals. Furthermore, we provide evidence that Ca2+ activity in the proximal tubule decreases with increasing distance from the glomerulus. Finally, we demonstrate that substantial changes in intracellular Ca2+ can be detected in proximal tubules in a cisplatin model of acute kidney injury, which can be linked to alterations in cell structure and transport function. In summary, we describe a powerful new tool to investigate how single cell behavior is integrated with whole organ structure and function and how it is altered in disease states relevant to humans.
Collapse
Affiliation(s)
| | - Dominik Haenni
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andreja Figurek
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
| |
Collapse
|
11
|
Imenez Silva PH, Katamesh-Benabbas C, Chan K, Pastor Arroyo EM, Knöpfel T, Bettoni C, Ludwig MG, Gasser JA, Brandao-Burch A, Arnett TR, Bonny O, Seuwen K, Wagner CA. The proton-activated ovarian cancer G protein-coupled receptor 1 (OGR1) is responsible for renal calcium loss during acidosis. Kidney Int 2020; 97:920-933. [DOI: 10.1016/j.kint.2019.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 11/29/2019] [Accepted: 12/05/2019] [Indexed: 12/19/2022]
|
12
|
Da Y, Akalya K, Murali T, Vathsala A, Tan CS, Low S, Lim HN, Teo BW, Lau T, Ong L, Chua HR. Serial Quantification of Urinary Protein Biomarkers to Predict Drug-induced Acute Kidney Injury. Curr Drug Metab 2020; 20:656-664. [PMID: 31296157 DOI: 10.2174/1389200220666190711114504] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 06/28/2019] [Accepted: 07/01/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND Drug-induced Acute Kidney Injury (AKI) develops in 10-15% of patients who receive nephrotoxic medications. Urinary biomarkers of renal tubular dysfunction may detect nephrotoxicity early and predict AKI. METHODS We prospectively studied patients who received aminoglycosides, vancomycin, amphotericin, or calcineurin inhibitors, and collected their serial urine while on therapy. Patients who developed drug-induced AKI (fulfilling KDIGO criteria) were matched with non-AKI controls in a 1:2 ratio. Their urine samples were batch-analyzed at time-intervals leading up to AKI onset; the latter benchmarked against the final day of nephrotoxic therapy in non- AKI controls. Biomarkers examined include clusterin, beta-2-microglobulin, KIM1, MCP1, cystatin-C, trefoil-factor- 3, NGAL, interleukin-18, GST-Pi, calbindin, and osteopontin; biomarkers were normalized with corresponding urine creatinine. RESULTS Nine of 84 (11%) patients developed drug-induced AKI. Biomarkers from 7 AKI cases with pre-AKI samples were compared with those from 14 non-AKI controls. Corresponding mean ages were 55(±17) and 52(±16) years; baseline eGFR were 99(±21) and 101(±24) mL/min/1.73m2 (all p=NS). Most biomarker levels peaked before the onset of AKI. Median levels of 5 biomarkers were significantly higher in AKI cases than controls at 1-3 days before AKI onset (all µg/mmol): clusterin [58(8-411) versus 7(3-17)], beta-2-microglobulin [1632(913-3823) versus 253(61-791)], KIM1 [0.16(0.13-0.76) versus 0.07(0.05-0.15)], MCP1 [0.40(0.16-1.90) versus 0.07(0.04-0.17)], and cystatin-C [33(27-2990) versus 11(7-19)], all p<0.05; their AUROC for AKI prediction were >0.80 (confidence intervals >0.50), with average accuracy highest for clusterin (86%), followed by beta-2-microglobulin, cystatin-C, MCP1, and KIM1 (57%) after cross-validation. CONCLUSION Serial surveillance of these biomarkers could improve the lead time for nephrotoxicity detection by days.
Collapse
Affiliation(s)
- Yi Da
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - K Akalya
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - Tanusya Murali
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - Anantharaman Vathsala
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - Chuen-Seng Tan
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore 119077, Singapore
| | - Sanmay Low
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - Hui-Ning Lim
- Department of Pharmacy, National University Hospital, Singapore 119074, Singapore
| | - Boon-Wee Teo
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - Titus Lau
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| | - Lizhen Ong
- Department of Laboratory Medicine, National University Hospital, Singapore 119074, Singapore
| | - Horng-Ruey Chua
- Division of Nephrology, University Medicine Cluster, National University Hospital, Singapore 119074, Singapore.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119077, Singapore
| |
Collapse
|
13
|
Ijomone OM, Aluko OM, Okoh COA, Martins AC, Aschner M. Role for calcium signaling in manganese neurotoxicity. J Trace Elem Med Biol 2019; 56:146-155. [PMID: 31470248 DOI: 10.1016/j.jtemb.2019.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND Calcium is an essential macronutrient that is involved in many cellular processes. Homeostatic control of intracellular levels of calcium ions [Ca2+] is vital to maintaining cellular structure and function. Several signaling molecules are involved in regulating Ca2+ levels in cells and perturbation of calcium signaling processes is implicated in several neurodegenerative and neurologic conditions. Manganese [Mn] is a metal which is essential for basic physiological functions. However, overexposure to Mn from environmental contamination and workplace hazards is a global concern. Mn overexposure leads to its accumulation in several human organs particularly the brain. Mn accumulation in the brain results in a manganism, a Parkinsonian-like syndrome. Additionally, Mn is a risk factor for several neurodegenerative diseases including Parkinson's disease and Alzheimer's disease. Mn neurotoxicity also affects several neurotransmitter systems including dopaminergic, cholinergic and GABAergic. The mechanisms of Mn neurotoxicity are still being elucidated. AIM The review will highlight a potential role for calcium signaling molecules in the mechanisms of Mn neurotoxicity. CONCLUSION Ca2+ regulation influences the neurodegenerative process and there is possible role for perturbed calcium signaling in Mn neurotoxicity. Mechanisms implicated in Mn-induced neurodegeneration include oxidative stress, generation of free radicals, and apoptosis. These are influenced by mitochondrial integrity which can be dependent on intracellular Ca2+ homeostasis. Nevertheless, further elucidation of the direct effects of calcium signaling dysfunction and calcium-binding proteins activities in Mn neurotoxicity is required.
Collapse
Affiliation(s)
- Omamuyovwi M Ijomone
- The Neuro- Lab, Department of Human Anatomy, Federal University of Technology Akure, Ondo, Nigeria.
| | - Oritoke M Aluko
- Department of Physiology, Federal University of Technology Akure, Ondo, Nigeria
| | - Comfort O A Okoh
- The Neuro- Lab, Department of Human Anatomy, Federal University of Technology Akure, Ondo, Nigeria
| | - Airton Cunha Martins
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States.
| |
Collapse
|
14
|
The single-cell transcriptomic landscape of early human diabetic nephropathy. Proc Natl Acad Sci U S A 2019; 116:19619-19625. [PMID: 31506348 PMCID: PMC6765272 DOI: 10.1073/pnas.1908706116] [Citation(s) in RCA: 305] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Single-nucleus RNA sequencing revealed gene expression changes in early diabetic nephropathy that promote urinary potassium secretion and decreased calcium and magnesium reabsorption. Multiple cell types exhibited angiogenic signatures, which may represent early signs of aberrant angiogenesis. These alterations may help to identify biomarkers for disease progression or signaling pathways amenable to early intervention. Diabetic nephropathy is characterized by damage to both the glomerulus and tubulointerstitium, but relatively little is known about accompanying cell-specific changes in gene expression. We performed unbiased single-nucleus RNA sequencing (snRNA-seq) on cryopreserved human diabetic kidney samples to generate 23,980 single-nucleus transcriptomes from 3 control and 3 early diabetic nephropathy samples. All major cell types of the kidney were represented in the final dataset. Side-by-side comparison demonstrated cell-type–specific changes in gene expression that are important for ion transport, angiogenesis, and immune cell activation. In particular, we show that the diabetic thick ascending limb, late distal convoluted tubule, and principal cells all adopt a gene expression signature consistent with increased potassium secretion, including alterations in Na+/K+-ATPase, WNK1, mineralocorticoid receptor, and NEDD4L expression, as well as decreased paracellular calcium and magnesium reabsorption. We also identify strong angiogenic signatures in glomerular cell types, proximal convoluted tubule, distal convoluted tubule, and principal cells. Taken together, these results suggest that increased potassium secretion and angiogenic signaling represent early kidney responses in human diabetic nephropathy.
Collapse
|
15
|
Singh N, Avigan ZM, Kliegel JA, Shuch BM, Montgomery RR, Moeckel GW, Cantley LG. Development of a 2-dimensional atlas of the human kidney with imaging mass cytometry. JCI Insight 2019; 4:129477. [PMID: 31217358 DOI: 10.1172/jci.insight.129477] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 05/10/2019] [Indexed: 12/19/2022] Open
Abstract
An incomplete understanding of the biology of the human kidney, including the relative abundances of and interactions between intrinsic and immune cells, has long constrained the development of therapies for kidney disease. The small amount of tissue obtained by renal biopsy has previously limited the ability to use patient samples for discovery purposes. Imaging mass cytometry (IMC) is an ideal technology for quantitative interrogation of scarce samples, permitting concurrent analysis of more than 40 markers on a single tissue section. Using a validated panel of metal-conjugated antibodies designed to confer unique signatures on the structural and infiltrating cells comprising the human kidney, we performed simultaneous multiplexed imaging with IMC in 23 channels on 16 histopathologically normal human samples. We devised a machine-learning pipeline (Kidney-MAPPS) to perform single-cell segmentation, phenotyping, and quantification, thus creating a spatially preserved quantitative atlas of the normal human kidney. These data define selected baseline renal cell types, respective numbers, organization, and variability. We demonstrate the utility of IMC coupled to Kidney-MAPPS to qualitatively and quantitatively distinguish individual cell types and reveal expected as well as potentially novel abnormalities in diseased versus normal tissue. Our studies define a critical baseline data set for future quantitative analysis of human kidney disease.
Collapse
Affiliation(s)
- Nikhil Singh
- Section of Nephrology, Department of Internal Medicine
| | | | | | | | | | - Gilbert W Moeckel
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | | |
Collapse
|
16
|
Metabolomic analysis reveals a protective effect of Fu-Fang-Jin-Qian-Chao herbal granules on oxalate-induced kidney injury. Biosci Rep 2019; 39:BSR20181833. [PMID: 30737304 PMCID: PMC6386768 DOI: 10.1042/bsr20181833] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/31/2019] [Accepted: 02/07/2019] [Indexed: 02/07/2023] Open
Abstract
Nephrolithiasis is one of the world’s major public health burdens with a high incidence and a risk of persistent renal dysfunction. Fu-Fang-Jin-Qian-Chao granules (FFJQC), a traditional Chinese herb formula, is commonly used in treatment of nephrolithiasis. However, the therapeutic mechanism of FFJQC on kidney stone has still been a mystery. The objective of the present study is to explore the therapeutic mechanism of FFJQC on kidney injury and identify unique metabolomics patterns using a mouse model of kidney stone induced by a calcium oxalate (CaOx) deposition. Von Kossa staining and immuno-histopathological staining of osteopontin (OPN), cluster of differentiation 44 (CD44) and calbindin-D28k were conducted on renal sections. Biochemical analysis was performed on serum, urine, and kidney tissues. A metabolomics approach based on ultra-HPLC coupled with quadrupole-TOF-MS (UHPLC-Q-TOF/MS) was used for serum metabolic profiling. The immunohistopathological and biochemical analysis showed the therapeutic benefits of FFJQC. The expression levels of OPN and CD44 were decreased while calbindin-D28k increased after the CaOx injured mice were treated with FFJQC. In addition, total of 81 serum metabolites were identified to be associated with protective effects of FFJQC on CaOx crystal injured mice. Most of these metabolites were involved in purine, amino acid, membrane lipid and energy metabolism. Potential metabolite biomarkers were found for CaOx crystal-induced renal damage. Potential metabolite biomarkers of CaOx crystal-induced renal damage were found. FFJQC shows therapeutic benefits on CaOx crystal injured mice via regulation of multiple metabolic pathways including amino acids, purine, pyrimidine, glycerolipid, arachidonic acid (AA), sphingolipid, glycerophospholipid, and fatty acid.
Collapse
|
17
|
Kirk J, Nicholson AR, Cassidy-Vu L. Implications of Magnesium in Diabetes. J Pharm Pract 2018. [DOI: 10.1177/0897190017738917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Julienne Kirk
- Department of Family and Community Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Allison R. Nicholson
- College of Pharmacy and Health Sciences, Campbell University, Buies Creek, NC, USA
| | - Lisa Cassidy-Vu
- Department of Family and Community Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| |
Collapse
|
18
|
Kieboom BCT, Zietse R, Ikram MA, Hoorn EJ, Stricker BH. Thiazide but not loop diuretics is associated with hypomagnesaemia in the general population. Pharmacoepidemiol Drug Saf 2018; 27:1166-1173. [PMID: 30095199 DOI: 10.1002/pds.4636] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 06/22/2018] [Accepted: 07/16/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE Hypomagnesaemia has been associated with various adverse outcomes. Loop and thiazide diuretics promote urinary magnesium excretion. However, it is unknown if this links to hypomagnesaemia. We study if loop or thiazide diuretic use affects serum magnesium levels and if it associates with hypomagnesaemia. In addition, we study the effect of combining a potassium-sparing diuretic with a thiazide diuretic on the presence of hypomagnesaemia. METHODS The study performed a cross-sectional analysis within 9820 participants from the prospective Rotterdam Study. Hypomagnesaemia was defined as a serum magnesium level ≤0.72 mmol/L. Participants were categorized by defined daily dose (DDD), and all analyses were adjusted for age, sex, BMI, eGFR, serum potassium levels, proton pump inhibitor use, and comorbidities. RESULTS Loop diuretic use was associated with higher serum magnesium levels (<1 DDD: 0.004 mmol/L 95% CI: -0.008; 0.017; 1 DDD: 0.023 mmol/L 95% CI: 0.013; 0.032; >1 DDD: 0.043 mmol/L 95% CI: 0.028; 0.057). Thiazide diuretic use was associated with lower serum magnesium levels (<1 DDD: -0.013 mmol/L 95% CI: -0.023; -0.002; ≥1 DDD: -0.018 mmol/L 95% CI: -0.028; -0.010), resulting in an increased odds ratio of hypomagnesaemia of 3.14 (95% CI: 1.67; 5.92) and 2.74 (95% CI: 1.57; 4.77), respectively. These effects were predominantly seen in participants using diuretics for more than 390 days. Combining thiazide diuretics with a potassium-sparing agent was not associated with lower serum magnesium levels or hypomagnesaemia. CONCLUSIONS Thiazide diuretic use is associated with lower serum magnesium levels and an increased risk of hypomagnesaemia. This increased risk is not seen in participants using a combination of thiazide diuretics with a potassium-sparing agent. The use of loop diuretics is not associated with an increased risk of hypomagnesaemia.
Collapse
Affiliation(s)
- Brenda C T Kieboom
- Department of Epidemiology, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands.,Department of Internal Medicine, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands.,Inspectorate for Health Care, Utrecht, the Netherlands
| | - Robert Zietse
- Department of Internal Medicine, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Ewout J Hoorn
- Department of Internal Medicine, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Bruno H Stricker
- Department of Epidemiology, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands.,Department of Internal Medicine, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands.,Inspectorate for Health Care, Utrecht, the Netherlands
| |
Collapse
|
19
|
Curry JN, Yu AS. Magnesium Handling in the Kidney. Adv Chronic Kidney Dis 2018; 25:236-243. [PMID: 29793662 DOI: 10.1053/j.ackd.2018.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/26/2017] [Accepted: 01/02/2018] [Indexed: 02/07/2023]
Abstract
Magnesium is a divalent cation that fills essential roles as regulator and cofactor in a variety of biological pathways, and maintenance of magnesium balance is vital to human health. The kidney, in concert with the intestine, has an important role in maintaining magnesium homeostasis. Although micropuncture and microperfusion studies in the mammalian nephron have shone a light on magnesium handling in the various nephron segments, much of what we know about the protein mediators of magnesium handling in the kidney have come from more recent genetic studies. In the proximal tubule and thick ascending limb, magnesium reabsorption is believed to occur primarily through the paracellular shunt pathway, which ultimately depends on the electrochemical gradient setup by active sodium reabsorption. In the distal convoluted tubule, magnesium transport is transcellular, although magnesium reabsorption also appears to be related to active sodium reabsorption in this segment. In addition, evidence suggests that magnesium transport is highly regulated, although a specific hormonal regulator of extracellular magnesium has yet to be identified.
Collapse
|
20
|
Parathyroid hormone and the regulation of renal tubular calcium transport. Curr Opin Nephrol Hypertens 2017; 26:405-410. [DOI: 10.1097/mnh.0000000000000347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
21
|
Ishizawa K, Xu N, Loffing J, Lifton RP, Fujita T, Uchida S, Shibata S. Potassium depletion stimulates Na-Cl cotransporter via phosphorylation and inactivation of the ubiquitin ligase Kelch-like 3. Biochem Biophys Res Commun 2016; 480:745-751. [PMID: 27942049 DOI: 10.1016/j.bbrc.2016.10.127] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Kelch-like 3 (KLHL3) is a component of an E3 ubiquitin ligase complex that regulates blood pressure by targeting With-No-Lysine (WNK) kinases for degradation. Mutations in KLHL3 cause constitutively increased renal salt reabsorption and impaired K+ secretion, resulting in hypertension and hyperkalemia. Although clinical studies have shown that dietary K+ intake affects blood pressure, the mechanisms have been obscure. In this study, we demonstrate that the KLHL3 ubiquitin ligase complex is involved in the low-K+-mediated activation of Na-Cl cotransporter (NCC) in the kidney. In the distal convoluted tubules of mice eating a low-K+ diet, we found increased KLHL3 phosphorylation at S433 (KLHL3S433-P), a modification that impairs WNK binding, and also reduced total KLHL3 levels. These changes are accompanied by the accumulation of the target substrate WNK4, and activation of the downstream kinases SPAK (STE20/SPS1-related proline-alanine-rich protein kinase) and OSR1 (oxidative stress-responsive 1), resulting in NCC phosphorylation and its accumulation at the plasma membrane. Increased phosphorylation of S433 was explained by increased levels of active, phosphorylated protein kinase C (but not protein kinase A), which directly phosphorylates S433. Moreover, in HEK cells expressing KLHL3 and WNK4, we showed that the activation of protein kinase C by phorbol 12-myristate 13-acetate induces KLHL3S433-P and increases WNK4 levels by abrogating its ubiquitination. These data demonstrate the role of KLHL3 in low-K+-mediated induction of NCC; this physiologic adaptation reduces distal electrogenic Na+ reabsorption, preventing further renal K+ loss but promoting increased blood pressure.
Collapse
Affiliation(s)
- Kenichi Ishizawa
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Ning Xu
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan; Department of Nephrology, Tianjin First Central Hospital, Tianjin, China
| | | | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, Connecticut, U.S.A
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research center for Advanced Science and Technology, The University of Tokyo, Japan
| | - Shunya Uchida
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan; Division of Clinical Epigenetics, Research center for Advanced Science and Technology, The University of Tokyo, Japan
| |
Collapse
|
22
|
Mutig K, Borowski T, Boldt C, Borschewski A, Paliege A, Popova E, Bader M, Bachmann S. Demonstration of the functional impact of vasopressin signaling in the thick ascending limb by a targeted transgenic rat approach. Am J Physiol Renal Physiol 2016; 311:F411-23. [PMID: 27306979 DOI: 10.1152/ajprenal.00126.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/09/2016] [Indexed: 11/22/2022] Open
Abstract
The antidiuretic hormone vasopressin (AVP) regulates renal salt and water reabsorption along the distal nephron and collecting duct system. These effects are mediated by vasopressin 2 receptors (V2R) and release of intracellular Gs-mediated cAMP to activate epithelial transport proteins. Inactivating mutations in the V2R gene lead to the X-linked form of nephrogenic diabetes insipidus (NDI), which has chiefly been related with impaired aquaporin 2-mediated water reabsorption in the collecting ducts. Previous work also suggested the AVP-V2R-mediated activation of Na(+)-K(+)-2Cl(-)-cotransporters (NKCC2) along the thick ascending limb (TAL) in the context of urine concentration, but its individual contribution to NDI or, more generally, to overall renal function was unclear. We hypothesized that V2R-mediated effects in TAL essentially determine its reabsorptive function. To test this, we reevaluated V2R expression. Basolateral membranes of medullary and cortical TAL were clearly stained, whereas cells of the macula densa were unreactive. A dominant-negative, NDI-causing truncated V2R mutant (Ni3-Glu242stop) was then introduced into the rat genome under control of the Tamm-Horsfall protein promoter to cause a tissue-specific AVP-signaling defect exclusively in TAL. Resulting Ni3-V2R transgenic rats revealed decreased basolateral but increased intracellular V2R signal in TAL epithelia, suggesting impaired trafficking of the receptor. Rats displayed significant baseline polyuria, failure to concentrate the urine in response to water deprivation, and hypercalciuria. NKCC2 abundance, phosphorylation, and surface expression were markedly decreased. In summary, these data indicate that suppression of AVP-V2R signaling in TAL causes major impairment in renal fluid and electrolyte handling. Our results may have clinical implications.
Collapse
Affiliation(s)
- Kerim Mutig
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Tordis Borowski
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Christin Boldt
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Aljona Borschewski
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Alexander Paliege
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| | - Elena Popova
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Michael Bader
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité Universitätsmedizin, Berlin, Germany; and
| |
Collapse
|