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Matsui S, Yamamoto T, Takabatake Y, Takahashi A, Namba-Hamano T, Matsuda J, Minami S, Sakai S, Yonishi H, Nakamura J, Maeda S, Matsumoto A, Matsui I, Yanagita M, Isaka Y. Empagliflozin protects the kidney by reducing toxic ALB (albumin) exposure and preventing autophagic stagnation in proximal tubules. Autophagy 2024:1-15. [PMID: 39385699 DOI: 10.1080/15548627.2024.2410621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 09/20/2024] [Accepted: 09/25/2024] [Indexed: 10/12/2024] Open
Abstract
The renoprotective effects of SLC5A2/SGLT2 (solute carrier 5 (sodium/glucose cotransporter), member 2) inhibitors have recently been demonstrated in non-diabetic chronic kidney disease (CKD), even without overt albuminuria. However, the mechanism underlying this renoprotection is largely unclear. We investigated the renoprotective mechanisms of the SLC5A2 inhibitor empagliflozin with a focus on ALB (albumin) reabsorption and macroautophagy/autophagy in proximal tubules using wild-type or drug-inducible lrp2/Megalin or atg5 knockout mice with high-fat diet (HFD)-induced obesity or 5/6 nephrectomy that elevated intraglomerular pressure without overt albuminuria. Empagliflozin treatment of HFD-fed mice reduced several hallmarks of lipotoxicity in the proximal tubules, such as phospholipid accumulation in the lysosome, inflammation and fibrosis. Empagliflozin, which decreases intraglomerular pressure, not only reduced the HFD-induced increase in ALB reabsorption via LRP2 in the proximal tubules (i.e. total nephron ALB filtration), as assessed by urinary ALB excretion caused by genetic ablation of Lrp2, but also ameliorated the HFD-induced imbalance in circulating ALB-bound fatty acids. Empagliflozin alleviated the HFD-induced increase in autophagic demand and successfully prevented autophagic stagnation in the proximal tubules. Similarly, empagliflozin decreased ALB exposure and autophagic demand in 5/6 nephrectomized mice. Finally, empagliflozin reduced HFD-induced vulnerability to ischemia-reperfusion injury, whereas LRP2 blockade and atg5 ablation separately diminished this effect. Our findings indicate that empagliflozin reduces ALB exposure and prevents autophagic stagnation in the proximal tubules even without overt albuminuria. Autophagy improvement may be critical for the renoprotection mediated by SLC5A2 inhibition.
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Affiliation(s)
- Sho Matsui
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takeshi Yamamoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshitsugu Takabatake
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Atsushi Takahashi
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tomoko Namba-Hamano
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun Matsuda
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Satoshi Minami
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shinsuke Sakai
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hiroaki Yonishi
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jun Nakamura
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Shihomi Maeda
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ayumi Matsumoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Isao Matsui
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for the Advanced Study of Human Biology, Kyoto University, Kyoto, Japan
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
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Goto S, Hosojima M, Kabasawa H, Arai K, Takemoto K, Aoki H, Komochi K, Kobayashi R, Sugita N, Endo T, Kaseda R, Yoshida Y, Narita I, Hirayama Y, Saito A. Megalin-related mechanism of hemolysis-induced acute kidney injury and the therapeutic strategy. J Pathol 2024; 263:315-327. [PMID: 38721910 DOI: 10.1002/path.6284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 02/08/2024] [Accepted: 03/15/2024] [Indexed: 06/12/2024]
Abstract
Hemolysis-induced acute kidney injury (AKI) is attributed to heme-mediated proximal tubule epithelial cell (PTEC) injury and tubular cast formation due to intratubular protein condensation. Megalin is a multiligand endocytic receptor for proteins, peptides, and drugs in PTECs and mediates the uptake of free hemoglobin and the heme-scavenging protein α1-microglobulin. However, understanding of how megalin is involved in the development of hemolysis-induced AKI remains elusive. Here, we investigated the megalin-related pathogenesis of hemolysis-induced AKI and a therapeutic strategy using cilastatin, a megalin blocker. A phenylhydrazine-induced hemolysis model developed in kidney-specific mosaic megalin knockout (MegKO) mice confirmed megalin-dependent PTEC injury revealed by the co-expression of kidney injury molecule-1 (KIM-1). In the hemolysis model in kidney-specific conditional MegKO mice, the uptake of hemoglobin and α1-microglobulin as well as KIM-1 expression in PTECs was suppressed, but tubular cast formation was augmented, likely due to the nonselective inhibition of protein reabsorption in PTECs. Quartz crystal microbalance analysis revealed that cilastatin suppressed the binding of megalin with hemoglobin and α1-microglobulin. Cilastatin also inhibited the specific uptake of fluorescent hemoglobin by megalin-expressing rat yolk sac tumor-derived L2 cells. In a mouse model of hemolysis-induced AKI, repeated cilastatin administration suppressed PTEC injury by inhibiting the uptake of hemoglobin and α1-microglobulin and also prevented cast formation. Hemopexin, another heme-scavenging protein, was also found to be a novel ligand of megalin, and its binding to megalin and uptake by PTECs in the hemolysis model were suppressed by cilastatin. Mass spectrometry-based semiquantitative analysis of urinary proteins in cilastatin-treated C57BL/6J mice indicated that cilastatin suppressed the reabsorption of a limited number of megalin ligands in PTECs, including α1-microglobulin and hemopexin. Collectively, cilastatin-mediated selective megalin blockade is an effective therapeutic strategy to prevent both heme-mediated PTEC injury and cast formation in hemolysis-induced AKI. © 2024 The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Sawako Goto
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Michihiro Hosojima
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hideyuki Kabasawa
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kaho Arai
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Kazuya Takemoto
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroyuki Aoki
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Koichi Komochi
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ryota Kobayashi
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Nanako Sugita
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Taeko Endo
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ryohei Kaseda
- Division of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Yutaka Yoshida
- Department of Bacteriology, 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
| | | | - Akihiko Saito
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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Itoh Y, Suzuki S, Mineo R, Sasaki S, Tamba S, Sugiyama T, Yamamoto K. Pseudo-nephropathy and hyper-excretion of urinary C-peptide: an overlooked adverse effect of an angiotensin receptor-neprilysin inhibitor (ARNI). Diabetol Int 2024; 15:616-620. [PMID: 39101167 PMCID: PMC11291816 DOI: 10.1007/s13340-024-00730-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 05/05/2024] [Indexed: 08/06/2024]
Abstract
Sacubitril/valsartan, which is a combined angiotensin receptor-neprilysin inhibitor (ARNI), is used for the treatment of chronic heart failure and hypertension. Substrates of neprilysin are numerous, and the systemic effects of an ARNI remain to be determined. Increased urinary C-peptide (UCPR) and urinary albumin (UAlb) excretion has been reported with the use of an ARNI, but the mechanism is still unknown. We report an 84-year-old man with type 2 diabetes and hypertension. His UAlb and UCPR excretion and (to a lesser degree) the estimated glomerular filtration rate were increased after ARNI administration. They returned to basal levels after discontinuing ARNI administration. There was little or no change in glycemic control. Therefore, increased glomerular permeability and filtration could partially explain how neprilysin inhibition led to an elevation in UCPR excretion, in addition to other mechanisms, such as impairment of the renal ability to degrade C-peptide. Physicians must be cautious when interpreting the insulin secretion capability by UCPR and nephropathy by UAlb in ARNI-treated patients with diabetes.
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Affiliation(s)
- Yoshito Itoh
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
| | - Shigehito Suzuki
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
| | - Ryohei Mineo
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
| | - Sho Sasaki
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
| | - Sachiko Tamba
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
| | - Takuya Sugiyama
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
| | - Koji Yamamoto
- Department of Endocrinology and Metabolism, Sumitomo Hospital, Osaka, 530-0005 Japan
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Shapira-Furman T, Domb AJ. Insulin Extended Release from PLA-PEG Stereocomplex Nanoparticles. Macromol Biosci 2024; 24:e2300497. [PMID: 38029318 DOI: 10.1002/mabi.202300497] [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: 10/31/2023] [Indexed: 12/01/2023]
Abstract
This report addresses the challenges of controlled drug delivery for peptide and protein therapeutics by introducing a novel approach of nano formulation fabricated in aqueous media applying stereo-interaction mechanism with poly(D-lactide)-polyethylene glycol (D-PLA-PEG). To overcome the inherent poor stability of peptide and protein therapeutics, stereocomplexation of the peptide, insulin, is applied, onto D-PLA-PEG in aqueous media. Nanoparticles of ≈400 nm are spontaneously formed when water-soluble D configured PLA-PEG diblock copolymer and L- configured insulin interlock into a stereocomplex, owing to their concave convex fitness. In vitro release of insulin from stereocomplex in phosphate buffer solution (PBS) pH 7.4 solution shows sustained release for 14 weeks. The therapeutic efficacy of the PLA-insulin stereocomplex nanoparticles are evaluated in diabetic Akita mice. Blood glucose levels and body weight are closely monitored for a period of 17 weeks, revealing a significant reduction in glucose levels of the Akita mice treated with insulin stereocomplex, as well as normal body weight gain. These findings suggest that the stereocomplex nanoparticles of insulin-D-PLA-PEG present a promising and effective sustained and extended release platform for insulin. Notably, the use of water-soluble D-PLA-PEG for stereocomplexation in water expands the applicability of this approach to fabricate controlled delivery systems for peptide and protein therapeutics.
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Affiliation(s)
- Tovi Shapira-Furman
- The Hebrew University of Jerusalem, Faculty of Medicine, School of Pharmacy, Jerusalem, 91120, Israel
| | - Abraham J Domb
- The Hebrew University of Jerusalem, Faculty of Medicine, School of Pharmacy, Jerusalem, 91120, Israel
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Gao WY, Tian MY, Li ML, Gao SR, Wei XL, Gao C, Zhou YY, Li T, Wang HJ, Bian BL, Si N, Zhao W, Zhao HY. Study on the potential mechanism of Qingxin Lianzi Yin Decoction on renoprotection in db/db mice via network pharmacology and metabolomics. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 126:155222. [PMID: 38382279 DOI: 10.1016/j.phymed.2023.155222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 11/04/2023] [Accepted: 11/13/2023] [Indexed: 02/23/2024]
Abstract
BACKGROUND Diabetic nephropathy (DN) was one of the most popular and most significant microvascular complications of diabetes mellitus. Qingxin Lianzi Yin Decoction (QXLZY) was a traditional Chinese classical formula, suitable for chronic urinary system diseases. QXLZY had good clinical efficacy in early DN, but the underlying molecular mechanism remained unrevealed. PURPOSE This study aimed to establish the content determination method of QXLZY index components and explore the mechanism of QXLZY on DN by network pharmacology and metabolomics studies. METHODS Firstly, the content determination methods of QXLZY were established with calycosin-7-O-β-d-glucoside, acteoside, baicalin and glycyrrhizic acid as index components. Secondly, pharmacological experiments of QXLZY were evaluated using db/db mice. UHPLC-LTQ-Orbitrap MS was used to carry out untargeted urine metabolomics, serum metabolomics, and kidney metabolomics studies. Thirdly, employing network pharmacology, key components and targets were analyzed. Finally, targeted metabolomics studies were performed on the endogenous constituents in biological samples for validation based on untargeted metabolomics results. RESULTS A method for the simultaneous determination of multiple index components in QXLZY was established, which passed the comprehensive methodological verification. It was simple, feasible, and scientific. The QXLZY treatment alleviated kidney injury of db/db mice, included the degree of histopathological damage and the level of urinary microalbumin/creatinine ratio. Untargeted metabolomics studies had identified metabolic dysfunction in pathways associated with amino acid metabolism in db/db mice. Treatment with QXLZY could reverse metabolite abnormalities and influence the pathways related to energy metabolism and amino acid metabolism. It had been found that pathways with a high degree were involved in signal transduction, prominently on amino acids metabolism and lipid metabolism, analyzed by network pharmacology. Disorders of amino acid metabolism did occur in db/db mice. QXLZY could revert the levels of metabolites, such as quinolinic acid, arginine, and asparagine. CONCLUSION This study was the first time to demonstrate that QXLZY alleviated diabetes-induced pathological changes in the kidneys of db/db mice by correcting disturbances in amino acid metabolism. This work could provide a new experimental basis and theoretical guidance for the rational application of QXLZY on DN, exploring the new pharmacological effect of traditional Chinese medicine, and promoting in-depth research and development.
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Affiliation(s)
- Wen-Ya Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Meng-Yao Tian
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Ming-Li Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Shuang-Rong Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Xiao-Lu Wei
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Chang Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yan-Yan Zhou
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Tao Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China; Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Hong-Jie Wang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Bao-Lin Bian
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Nan Si
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
| | - Wei Zhao
- Center for Drug Evaluation, National Medical Products Administration, Beijing 100022, China.
| | - Hai-Yu Zhao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
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Gao W, Gao S, Zhang Y, Wang M, Liu Y, Li T, Gao C, Zhou Y, Bian B, Wang H, Wei X, Sato T, Si N, Zhao W, Zhao H. Altered metabolic profiles and targets relevant to the protective effect of acteoside on diabetic nephropathy in db/db mice based on metabolomics and network pharmacology studies. JOURNAL OF ETHNOPHARMACOLOGY 2024; 318:117073. [PMID: 37619856 DOI: 10.1016/j.jep.2023.117073] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 07/26/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Diabetic nephropathy (DN) was a major cause of end-stage renal failure and a common microvascular complication in patients with diabetes mellitus (DM). Acteoside (ACT) was the main ingredient extracted from the leaves of Rehmannia glutinosa, which had the functions of entering the lung, moisturizing the skin and relieving itching, nourishing yin and tonifying the kidney, cooling blood, and stopping bleeding. ACT had attracted worldwide interest because of its therapeutic effects on DM and its complications. AIM OF THE STUDY To clarify the metabolic profiles and targets of ACT in db/db mice based on metabolomics and network pharmacology studies. MATERIALS AND METHODS Db/db mice were used to observe the biochemical indices and histopathological changes in the kidney to evaluate the pharmacological effects of ACT on DN. Untargeted metabolomics studies were performed to investigate by UHPLC-LTQ-Orbitrap MS on urine, serum, and kidney samples. The key targets and pathways were analyzed by network pharmacology. For the pathways enriched by untargeted metabolomics, targeted metabolomics by UHPLC-QQQ-MS/MS was performed in kidney samples for validation. Sensitive biomarkers in kidney samples were evaluated. The effect of ACT on the improvement of DN from the perspective of metabolism of small molecules in vivo was described. RESULTS ACT could delay the progression of DN and improve the degree of histopathological damage to the kidney. The pathways were focused on amino acid metabolism by untargeted metabolomics. Through network pharmacology analysis, the effect pathways were related to signal transduction, carbohydrate, lipid, amino acid metabolism and mainly affected the endocrine and immune systems. Amino acid metabolism was disturbed in the kidney of db/db mice, which could be callback by ACT, such as tryptophan, glutamine, cysteine, leucine, threonine, proline, phenylalanine, histidine, serine, arginine, asparagine by targeted metabolomics. CONCLUSIONS In conclusion, this study provided strong support for ACT on DN treatment in clinics. Meanwhile, the Rehmannia glutinosa was used fully to raise the income level of farmers economically, while achieving the social benefit of empowering rural revitalization.
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Affiliation(s)
- Wenya Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Shuangrong Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Yan Zhang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Mengxiao Wang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Yuyang Liu
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Tao Li
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China; Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Chang Gao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Yanyan Zhou
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Baolin Bian
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Hongjie Wang
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Xiaolu Wei
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Takashi Sato
- Department of Biochemistry, Tokyo University of Pharmacy and Life Sciences, Tokyo 192-0392, Japan
| | - Nan Si
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
| | - Wei Zhao
- Center for Drug Evaluation, National Medical Products Administration, Beijing, 100022, China.
| | - Haiyu Zhao
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
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7
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Birn H, Nielsen R, Weyer K. Tubular albumin uptake: is there evidence for a quantitatively important, receptor-independent mechanism? Kidney Int 2023; 104:1069-1073. [PMID: 37981430 DOI: 10.1016/j.kint.2023.07.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 07/06/2023] [Accepted: 07/11/2023] [Indexed: 11/21/2023]
Affiliation(s)
- Henrik Birn
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark.
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Kathrin Weyer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Liu C, Zeng H, Jiang R, Wang K, Ouyang J, Wen S, Peng L, Xu H, Huang J, Liu Z. Effects of Mulberry Leaf Fu Tea on the Intestines and Intestinal Flora of Goto-Kakizaki Type 2 Diabetic Rats. Foods 2023; 12:4006. [PMID: 37959125 PMCID: PMC10648540 DOI: 10.3390/foods12214006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/29/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
Type 2 diabetes mellitus is a disease caused by hyperglycemia, an imbalance in the intestinal flora and disruption of the endocrine system. At present, it is primarily controlled through drug treatment and an improved diet. Mulberry leaf and fu brick tea were considered to have excellent hypoglycemic effects. This study used mulberry leaves and fu brick tea as raw materials to develop a dietary regulator that can assist in the prevention and alleviation of diabetes. The experiment used the Goto-Kakizaki (GK) rat model to investigate the hypoglycemic effect of mulberry leaf fu tea (MFT) and its influence on the intestinal flora of diabetic rats through methods including ELISA, tissue section observation and 16S RNA microbial sequencing. The results showed that, compared with the GK group, the intervention of mulberry leaf fu tea significantly reduced the activities of α-glucosidase (p < 0.05) and α-amylase (p < 0.05) in the duodenum of GK diabetic rats. The height of the duodenal villi was significantly reduced (p < 0.001), leading to decreased intestinal sugar absorption. At the same time, MFT alleviates the imbalance of intestinal flora caused by high blood sugar, promotes the growth of beneficial bacteria (Lactobacillus, Bifidobacterium, etc.), and inhibits the reproduction of harmful bacteria (Blautia, Klebsiella, Helicobacter, Alistipes, etc.). MFT helps reduce the secretion of toxic substances (lipopolysaccharide, p < 0.001), decreases oxidative stress and inflammation, mitigates organ damage, and improves symptoms of diabetes. Finally, the random blood glucose value of GK rats dropped from 22.79 mmol/L to 14.06 mmol/L. In summary, mulberry leaf fu tea can lower sugar absorption in diabetic rats, reduce the body's oxidative stress and inflammatory response, regulate intestinal flora, and reduce blood sugar levels in GK rats. It is hinted that mulberry leaf fu tea could be used as a functional drink to help prevent the occurrence of diabetes.
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Affiliation(s)
- Changwei Liu
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Hongzhe Zeng
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Ronggang Jiang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Kuofei Wang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Jian Ouyang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Shuai Wen
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Liyuan Peng
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Hao Xu
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
| | - Jianan Huang
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
- National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Changsha 410128, China
- Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops, Ministry of Agriculture and Rural Affairs of China, Hunan Agricultural University, Changsha 410128, China
| | - Zhonghua Liu
- Key Laboratory of Tea Science of Ministry of Education, Hunan Agricultural University, Changsha 410128, China
- National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Changsha 410128, China
- Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Changsha 410128, China
- Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops, Ministry of Agriculture and Rural Affairs of China, Hunan Agricultural University, Changsha 410128, China
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9
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Goto S, Yoshida Y, Hosojima M, Kuwahara S, Kabasawa H, Aoki H, Iida T, Sawada R, Ugamura D, Yoshizawa Y, Takemoto K, Komochi K, Kobayashi R, Kaseda R, Yaoita E, Nagatoishi S, Narita I, Tsumoto K, Saito A. Megalin is involved in angiotensinogen-induced, angiotensin II-mediated ERK1/2 signaling to activate Na + -H + exchanger 3 in proximal tubules. J Hypertens 2023; 41:1831-1843. [PMID: 37682076 DOI: 10.1097/hjh.0000000000003555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
BACKGROUND Kidney angiotensin (Ang) II is produced mainly from liver-derived, glomerular-filtered angiotensinogen (AGT). Podocyte injury has been reported to increase the kidney Ang II content and induce Na + retention depending on the function of megalin, a proximal tubular endocytosis receptor. However, how megalin regulates the renal content and action of Ang II remains elusive. METHODS We used a mass spectrometry-based, parallel reaction-monitoring assay to quantitate Ang II in plasma, urine, and kidney homogenate of kidney-specific conditional megalin knockout (MegKO) and control (Ctl) mice. We also evaluated the pathophysiological changes in both mouse genotypes under the basal condition and under the condition of increased glomerular filtration of AGT induced by administration of recombinant mouse AGT (rec-mAGT). RESULTS Under the basal condition, plasma and kidney Ang II levels were comparable in the two mouse groups. Ang II was detected abundantly in fresh spot urine in conditional MegKO mice. Megalin was also found to mediate the uptake of intravenously administered fluorescent Ang II by PTECs. Administration of rec-mAGT increased kidney Ang II, exerted renal extracellular signal-regulated kinase 1/2 (ERK1/2) signaling, activated proximal tubular Na + -H + exchanger 3 (NHE3), and decreased urinary Na + excretion in Ctl mice, whereas these changes were suppressed but urinary Ang II was increased in conditional MegKO mice. CONCLUSION Increased glomerular filtration of AGT is likely to augment Ang II production in the proximal tubular lumen. Thus, megalin-dependent Ang II uptake should be involved in the ERK1/2 signaling that activates proximal tubular NHE3 in vivo , thereby causing Na + retention.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Ryohei Kaseda
- Department of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City, Niigata
| | | | | | - Ichiei Narita
- Department of Clinical Nephrology and Rheumatology, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City, Niigata
| | - Kouhei Tsumoto
- The Institute of Medical Science and Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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10
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Thévenod F, Herbrechter R, Schlabs C, Pethe A, Lee WK, Wolff NA, Roussa E. Role of the SLC22A17/lipocalin-2 receptor in renal endocytosis of proteins/metalloproteins: a focus on iron- and cadmium-binding proteins. Am J Physiol Renal Physiol 2023; 325:F564-F577. [PMID: 37589051 DOI: 10.1152/ajprenal.00020.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 08/18/2023] Open
Abstract
The transmembrane protein SLC22A17 [or the neutrophil gelatinase-associated lipocalin/lipocalin-2 (LCN2)/24p3 receptor] is an atypical member of the SLC22 family of organic anion and cation transporters: it does not carry typical substrates of SLC22 transporters but mediates receptor-mediated endocytosis (RME) of LCN2. One important task of the kidney is the prevention of urinary loss of proteins filtered by the glomerulus by bulk reabsorption of multiple ligands via megalin:cubilin:amnionless-mediated endocytosis in the proximal tubule (PT). Accordingly, overflow, glomerular, or PT damage, as in Fanconi syndrome, results in proteinuria. Strikingly, up to 20% of filtered proteins escape the PT under physiological conditions and are reabsorbed by the distal nephron. The renal distal tubule and collecting duct express SLC22A17, which mediates RME of filtered proteins that evade the PT but with limited capacity to prevent proteinuria under pathological conditions. The kidney also prevents excretion of filtered essential and nonessential transition metals, such as iron or cadmium, respectively, that are largely bound to proteins with high affinity, e.g., LCN2, transferrin, or metallothionein, or low affinity, e.g., microglobulins or albumin. Hence, increased uptake of transition metals may cause nephrotoxicity. Here, we assess the literature on SLC22A17 structure, topology, tissue distribution, regulation, and assumed functions, emphasizing renal SLC22A17, which has relevance for physiology, pathology, and nephrotoxicity due to the accumulation of proteins complexed with transition metals, e.g., cadmium or iron. Other putative renal functions of SLC22A17, such as its contribution to osmotic stress adaptation, protection against urinary tract infection, or renal carcinogenesis, are discussed.
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Affiliation(s)
- Frank Thévenod
- Institute for Physiology, Pathophysiology and Toxicology, Center for Biomedical Education and Research, Witten/Herdecke University, Witten, Germany
- Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Bielefeld, Germany
| | - Robin Herbrechter
- Institute for Physiology, Pathophysiology and Toxicology, Center for Biomedical Education and Research, Witten/Herdecke University, Witten, Germany
| | - Carolin Schlabs
- Institute for Physiology, Pathophysiology and Toxicology, Center for Biomedical Education and Research, Witten/Herdecke University, Witten, Germany
| | - Abhishek Pethe
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Wing-Kee Lee
- Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Bielefeld, Germany
| | - Natascha A Wolff
- Institute for Physiology, Pathophysiology and Toxicology, Center for Biomedical Education and Research, Witten/Herdecke University, Witten, Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg im Breisgau, Germany
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11
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Kunke M, Knöfler H, Dahlke E, Zanon Rodriguez L, Böttner M, Larionov A, Saudenova M, Ohrenschall GM, Westermann M, Porubsky S, Bernardes JP, Häsler R, Magnin JL, Koepsell H, Jouret F, Theilig F. Targeted deletion of von-Hippel-Lindau in the proximal tubule conditions the kidney against early diabetic kidney disease. Cell Death Dis 2023; 14:562. [PMID: 37626062 PMCID: PMC10457389 DOI: 10.1038/s41419-023-06074-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/01/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023]
Abstract
Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease. Glomerular hyperfiltration and albuminuria subject the proximal tubule (PT) to a subsequent elevation of workload, growth, and hypoxia. Hypoxia plays an ambiguous role in the development and progression of DKD and shall be clarified in our study. PT-von-Hippel-Lindau (Vhl)-deleted mouse model in combination with streptozotocin (STZ)-induced type I diabetes mellitus (DM) was phenotyped. In contrary to PT-Vhl-deleted STZ-induced type 1 DM mice, proteinuria and glomerular hyperfiltration occurred in diabetic control mice the latter due to higher nitric oxide synthase 1 and sodium and glucose transporter expression. PT Vhl deletion and DKD share common alterations in gene expression profiles, including glomerular and tubular morphology, and tubular transport and metabolism. Compared to diabetic control mice, the most significantly altered in PT Vhl-deleted STZ-induced type 1 DM mice were Ldc-1, regulating cellular oxygen consumption rate, and Zbtb16, inhibiting autophagy. Alignment of altered genes in heat maps uncovered that Vhl deletion prior to STZ-induced DM preconditioned the kidney against DKD. HIF-1α stabilization leading to histone modification and chromatin remodeling resets most genes altered upon DKD towards the control level. These data demonstrate that PT HIF-1α stabilization is a hallmark of early DKD and that targeting hypoxia prior to the onset of type 1 DM normalizes renal cell homeostasis and prevents DKD development.
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Affiliation(s)
- Madlen Kunke
- Institute of Anatomy, Christian Albrechts-University Kiel, Kiel, Germany
| | - Hannah Knöfler
- Institute of Anatomy, Christian Albrechts-University Kiel, Kiel, Germany
| | - Eileen Dahlke
- Institute of Anatomy, Christian Albrechts-University Kiel, Kiel, Germany
| | | | - Martina Böttner
- Institute of Anatomy, Christian Albrechts-University Kiel, Kiel, Germany
| | - Alexey Larionov
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | | | | | | | | | - Joana P Bernardes
- Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Kiel, Germany
| | - Robert Häsler
- Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Kiel, Germany
| | | | - Hermann Koepsell
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - François Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA), Cardiovascular Sciences, University of Liège (ULiège), Liège, Belgium
- Division of Nephrology, CHU of Liège, University of Liège (CHU ULiège), Liège, Belgium
| | - Franziska Theilig
- Institute of Anatomy, Christian Albrechts-University Kiel, Kiel, Germany.
- Institute of Anatomy, Department of Medicine, University of Fribourg, Fribourg, Switzerland.
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12
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Shimada S, Hoffmann BR, Yang C, Kurth T, Greene AS, Liang M, Dash RK, Cowley AW. Metabolic Responses of Normal Rat Kidneys to a High Salt Intake. FUNCTION 2023; 4:zqad031. [PMID: 37575482 PMCID: PMC10413938 DOI: 10.1093/function/zqad031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 08/15/2023] Open
Abstract
In this study, novel methods were developed, which allowed continuous (24/7) measurement of arterial blood pressure and renal blood flow in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O2 and metabolites. Specifically, the study determined the effects of a high salt (HS; 4.0% NaCl) diet upon whole kidney O2 consumption and arterial and renal venous plasma metabolomic profiles of normal Sprague-Dawley rats. A separate group of rats was studied to determine changes in the cortex and outer medulla tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to 4.0% NaCl diet. In addition, targeted mRNA expression analysis of cortical segments was performed. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. A novel finding was the increased expression of glycolysis-related genes in Cx and isolated proximal tubular segments in response to an HS diet, consistent with increased release of pyruvate and lactate from the kidney to the renal venous blood. Data suggests that aerobic glycolysis (eg, Warburg effect) may contribute to energy production under these circumstances. The study provides evidence that kidney metabolism responds to an HS diet enabling enhanced energy production while protecting from oxidative stress and injury. Metabolomic and transcriptomic analysis of kidneys of Sprague-Dawley rats fed a high salt diet.
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Affiliation(s)
- Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian R Hoffmann
- Mass Spectrometry and Protein Chemistry, Protein Sciences, The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Andrew S Greene
- Mass Spectrometry and Protein Chemistry, Protein Sciences, The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Mingyu Liang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ranjan K Dash
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI 53226, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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13
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Fujino M, Morito N, Hayashi T, Ojima M, Ishibashi S, Kuno A, Koshiba S, Yamagata K, Takahashi S. Transcription factor c-Maf deletion improves streptozotocin-induced diabetic nephropathy by directly regulating Sglt2 and Glut2. JCI Insight 2023; 8:163306. [PMID: 36787192 PMCID: PMC10070115 DOI: 10.1172/jci.insight.163306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 02/01/2023] [Indexed: 02/15/2023] Open
Abstract
The transcription factor c-Maf has been widely studied and has been reported to play a critical role in embryonic kidney development; however, the postnatal functions of c-Maf in adult kidneys remain unknown as c-Maf-null C57BL/6J mice exhibit embryonic lethality. In this study, we investigated the role of c-Maf in adult mouse kidneys by comparing the phenotypes of tamoxifen-inducible (TAM-inducible) c-Maf-knockout mice (c-Maffl/fl; CAG-Cre-ERTM mice named "c-MafΔTAM") with those of c-Maffl/fl control mice, 10 days after TAM injection [TAM(10d)]. In addition, we examined the effects of c-Maf deletion on diabetic conditions by injecting the mice with streptozotocin, 4 weeks before TAM injection. c-MafΔTAM mice displayed primary glycosuria caused by sodium-glucose cotransporter 2 (Sglt2) and glucose transporter 2 (Glut2) downregulation in the kidneys without diabetes, as well as morphological changes and life-threatening injuries in the kidneys on TAM(10d). Under diabetic conditions, c-Maf deletion promoted recovery from hyperglycemia and suppressed albuminuria and diabetic nephropathy by causing similar effects as did Sglt2 knockout and SGLT2 inhibitors. In addition to demonstrating the potentially unique gene regulation of c-Maf, these findings highlight the renoprotective effects of c-Maf deficiency under diabetic conditions and suggest that c-Maf could be a novel therapeutic target gene for treating diabetic nephropathy.
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Affiliation(s)
- Mitsunori Fujino
- Department of Anatomy and Embryology, Faculty of Medicine
- PhD Program in Human Biology, School of Integrative and Global Majors
| | - Naoki Morito
- Department of Nephrology, Faculty of Medicine; and
| | - Takuto Hayashi
- Department of Anatomy and Embryology, Faculty of Medicine
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Masami Ojima
- Department of Anatomy and Embryology, Faculty of Medicine
| | - Shun Ishibashi
- Department of Anatomy and Embryology, Faculty of Medicine
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Akihiro Kuno
- Department of Anatomy and Embryology, Faculty of Medicine
| | - Seizo Koshiba
- Tohoku Medical Megabank Organization and
- Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, Sendai, Japan
| | | | - Satoru Takahashi
- Department of Anatomy and Embryology, Faculty of Medicine
- Laboratory Animal Resource Center
- Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA)
- International Institute for Integrative Sleep Medicine (WPI-IIIS), and
- Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
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14
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Shimada S, Hoffmann BR, Yang C, Kurth T, Greene AS, Liang M, Dash RK, Cowley AW. Metabolic responses of normal rat kidneys to a high salt intake. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524636. [PMID: 36711564 PMCID: PMC9882299 DOI: 10.1101/2023.01.18.524636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In the present study, novel methods were developed which allowed continuous (24/7) measurement of blood pressure (BP) and renal blood flow (RBF) in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O 2 and metabolites. The study determined the effects of a high salt (HS) diet upon whole kidney O 2 consumption and the metabolomic profiles of normal Sprague Dawley (SD) rats. A separate group of rats was studied to determine changes in the cortex (Cx) and outer medulla (OM) tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to a 4.0% NaCl diet. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O 2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. Increased glycolysis was evident with the elevation of mRNA expression encoding key glycolytic enzymes and release of pyruvate and lactate from the kidney in the renal venous blood. Glycolytic production of NADH is used in either the production of lactate or oxidized via the malate aspartate shuttle. Aerobic glycolysis (e.g., Warburg-effect) may account for the needed increase in cellular energy. The study provides evidence that kidney metabolism responds to a HS diet enabling enhanced energy production while protecting from oxidate stress and injury.
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15
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Urinary Markers of Tubular Injury and Renal Fibrosis in Patients with Type 2 Diabetes and Different Phenotypes of Chronic Kidney Disease. Life (Basel) 2023; 13:life13020343. [PMID: 36836700 PMCID: PMC9961033 DOI: 10.3390/life13020343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/21/2023] [Accepted: 01/22/2023] [Indexed: 01/31/2023] Open
Abstract
This study assessed the urinary excretion of markers and mediators of tubular injury and renal fibrosis in patients with type 2 diabetes (T2D) and non-albuminuric and albuminuric patterns of chronic kidney disease (CKD). One hundred and forty patients with long-term T2D and different patterns of CKD and twenty non-diabetic individuals were included. Urinary retinol-binding protein 4 (RBP-4), glutathione-S-transferase α1 and π (GST-α1 and GST-π), transforming growth factor β (TGF-β), type I and type IV collagen (Col1 and Col4), bone morphogenic protein 7 (BMP-7), and hepatocyte growth factor (HGF) were assessed by ELISA. Patients with T2D demonstrated increased urinary excretion of RBP-4, GST-π, Col4, BMP-7, and HGF (all p < 0.05 vs. control). The excretion of RBP-4, GST-π, Col1, and Col4 was increased in patients with elevated albumin-to-creatinine ratio (UACR; all p < 0.05 vs. control), while BMP-7 and HGF were increased innormoalbuminuric patients also (p < 0.05). Urinary RBP-4, GST-α1, Col1, Col4, and HGF correlated positively with UACR; meanwhile, no correlations with glomerular filtration rate were found. The results demonstrate that elevated urinary excretions of the markers of tubular injury (RBP-4, GST-π) and renal fibrosis (Col1, Col4), as well as HGF, an antifibrotic regulator, are associated with the albuminuric pattern of CKD in subjects with T2D.
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16
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Elsakka EGE, Mokhtar MM, Hegazy M, Ismail A, Doghish AS. Megalin, a multi-ligand endocytic receptor, and its participation in renal function and diseases: A review. Life Sci 2022; 308:120923. [PMID: 36049529 DOI: 10.1016/j.lfs.2022.120923] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/13/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022]
Abstract
The endocytosis mechanism is a complicated system that is essential for cell signaling and survival. Megalin, a membrane-associated endocytic receptor, and its related proteins such as cubilin, the neonatal Fc receptor for IgG, and NaPi-IIa are important in receptors-mediated endocytosis. Physiologically, megalin uptakes plasma vitamins and proteins from primary urine, preventing their loss. It also facilitates tubular retrieval of solutes and endogenous components that may be involved in modulation and recovery from kidney injuries. Moreover, megalin is responsible for endocytosis of xenobiotics and drugs in renal tubules, increasing their half-life and/or their toxicity. Fluctuations in megalin expression and/or functionality due to changes in its regulatory mechanisms are associated with some sort of kidney injury. Also, it's an important component of several pathological conditions, including diabetic nephropathy and Dent disease. Thus, exploring the fundamental role of megalin in the kidney might help in the protection and/or treatment of multiple kidney-related diseases. Hence, this review aimed to explore the physiological roles of megalin in the kidney and their implications for kidney-related injuries.
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Affiliation(s)
- Elsayed G E Elsakka
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt.
| | - Mahmoud Mohamed Mokhtar
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Maghawry Hegazy
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed Ismail
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed S Doghish
- Department of Biochemistry, Faculty of Pharmacy, Badr University in Cairo (BUC), Badr City, Cairo 11829, Egypt.
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17
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Li N, Zhou H. Sodium-glucose Cotransporter Type 2 Inhibitors: A New Insight into the Molecular Mechanisms of Diabetic Nephropathy. Curr Pharm Des 2022; 28:2131-2139. [PMID: 35718973 DOI: 10.2174/1381612828666220617153331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 03/15/2022] [Indexed: 11/22/2022]
Abstract
Diabetic nephropathy is one of the chronic microvascular complications of diabetes and is a leading cause of end-stage renal disease. Fortunately, clinical trials have demonstrated that sodium-glucose cotransporter type 2 inhibitors could decrease proteinuria and improve renal endpoints and are promising agents for the treatment of diabetic nephropathy. The renoprotective effects of sodium-glucose cotransporter type 2 inhibitors cannot be simply attributed to their advantages in aspects of metabolic benefits, such as glycemic control, lowering blood pressure, and control of serum uric acid, or improving hemodynamics associated with decreased glomerular filtration pressure. Some preclinical evidence suggests that sodium-glucose cotransporter type 2 inhibitors exert their renoprotective effects by multiple mechanisms, including attenuation of oxidative and endoplasmic reticulum stresses, anti-fibrosis and anti-inflammation, protection of podocytes, suppression of megalin function, improvement of renal hypoxia, restored mitochondrial dysfunction and autophagy, as well as inhibition of sodium-hydrogen exchanger 3. In the present study, the detailed molecular mechanisms of sodium-glucose cotransporter type 2 inhibitors with the actions of diabetic nephropathy were reviewed, with the purpose of providing the basis for drug selection for the treatment of diabetic nephropathy.
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Affiliation(s)
- Na Li
- Department of Endocrinology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hong Zhou
- Department of Endocrinology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
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18
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Molitoris BA, Sandoval RM, Yadav SPS, Wagner MC. Albumin Uptake and Processing by the Proximal Tubule: Physiologic, Pathologic and Therapeutic Implications. Physiol Rev 2022; 102:1625-1667. [PMID: 35378997 PMCID: PMC9255719 DOI: 10.1152/physrev.00014.2021] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
For nearly 50 years the proximal tubule (PT) has been known to reabsorb, process, and either catabolize or transcytose albumin from the glomerular filtrate. Innovative techniques and approaches have provided insights into these processes. Several genetic diseases, nonselective PT cell defects, chronic kidney disease (CKD), and acute PT injury lead to significant albuminuria, reaching nephrotic range. Albumin is also known to stimulate PT injury cascades. Thus, the mechanisms of albumin reabsorption, catabolism, and transcytosis are being reexamined with the use of techniques that allow for novel molecular and cellular discoveries. Megalin, a scavenger receptor, cubilin, amnionless, and Dab2 form a nonselective multireceptor complex that mediates albumin binding and uptake and directs proteins for lysosomal degradation after endocytosis. Albumin transcytosis is mediated by a pH-dependent binding affinity to the neonatal Fc receptor (FcRn) in the endosomal compartments. This reclamation pathway rescues albumin from urinary losses and cellular catabolism, extending its serum half-life. Albumin that has been altered by oxidation, glycation, or carbamylation or because of other bound ligands that do not bind to FcRn traffics to the lysosome. This molecular sorting mechanism reclaims physiological albumin and eliminates potentially toxic albumin. The clinical importance of PT albumin metabolism has also increased as albumin is now being used to bind therapeutic agents to extend their half-life and minimize filtration and kidney injury. The purpose of this review is to update and integrate evolving information regarding the reabsorption and processing of albumin by proximal tubule cells including discussion of genetic disorders and therapeutic considerations.
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Affiliation(s)
- Bruce A. Molitoris
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Dept.of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Ruben M. Sandoval
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Shiv Pratap S. Yadav
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Mark C. Wagner
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States
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19
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Kozyraki R, Verroust P, Cases O. Cubilin, the intrinsic factor-vitamin B12 receptor. VITAMINS AND HORMONES 2022; 119:65-119. [PMID: 35337634 DOI: 10.1016/bs.vh.2022.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cubilin (CUBN), the intrinsic factor-vitamin B12 receptor is a large endocytic protein involved in various physiological functions: vitamin B12 uptake in the gut; reabsorption of albumin and maturation of vitamin D in the kidney; nutrient delivery during embryonic development. Cubilin is an atypical receptor, peripherally associated to the plasma membrane. The transmembrane proteins amnionless (AMN) and Lrp2/Megalin are the currently known molecular partners contributing to plasma membrane transport and internalization of Cubilin. The role of Cubilin/Amn complex in the handling of vitamin B12 in health and disease has extensively been studied and so is the role of the Cubilin-Lrp2 tandem in renal pathophysiology. Accumulating evidence strongly supports a role of Cubilin in some developmental defects including impaired closure of the neural tube. Are these defects primarily caused by the dysfunction of a specific Cubilin ligand or are they secondary to impaired vitamin B12 or protein uptake? We will present the established Cubilin functions, discuss the developmental data and provide an overview of the emerging implications of Cubilin in the field of cardiovascular disease and cancer pathogenesis.
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Affiliation(s)
- Renata Kozyraki
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France.
| | - Pierre Verroust
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
| | - Olivier Cases
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, Paris, France
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20
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Edwards A, Long KR, Baty CJ, Shipman KE, Weisz OA. Modeling normal and nephrotic axial uptake of albumin and other filtered proteins along the proximal tubule. J Physiol 2022; 600:1933-1952. [PMID: 35178707 PMCID: PMC9012691 DOI: 10.1113/jp282885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 02/10/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We used new and published data to develop a mathematical model that predicts the profile of albumin uptake in the mouse proximal tubule (PT) in normal and nephrotic states, and partially accounts for competitive inhibition of uptake by normally filtered and pathologic ligands. Three pathways, consisting of high-affinity uptake by cubilin receptors, low-affinity uptake by megalin receptors, and fluid phase uptake, contribute to the overall retrieval of filtered proteins. The axial profile and efficiency of protein uptake depend on the initial filtrate composition and the individual protein affinities for megalin and cubilin. Under normal conditions, the majority of albumin is retrieved in S1 but shifts to S2 under nephrotic conditions. Other proteins exhibit different uptake profiles. Our model explains how tubular proteinuria can occur despite a large excess in potential PT uptake capacity. ABSTRACT Recent studies indicate that filtered albumin is retrieved in the proximal tubule (PT) via three pathways: receptor-mediated endocytosis via cubilin (high affinity) and megalin (low affinity), and fluid-phase uptake. Expression of megalin is required to maintain all three pathways, making it challenging to determine their respective contributions. Moreover, uptake of filtered molecules varies between the sub-segments (S1, S2, and S3) that make up the PT. Here we used new and published data to develop a mathematical model that predicts the rates of albumin uptake in mouse PT sub-segments in normal and nephrotic states, and partially accounts for competition by β2-microglobulin (β2m) and Immunoglobulin G (IgG). Our simulations indicate that receptor-mediated, rather than fluid-phase uptake, accounts for the vast majority of ligand recovery. Our model predicts that ∼75% of normally filtered albumin is reabsorbed via cubilin; however, megalin-mediated uptake predominates under nephrotic conditions. Our results also suggest that ∼80% of albumin is normally recovered in S1, whereas nephrotic conditions or knockout of cubilin shifts the bulk of albumin uptake to S2. The model predicts β2m and IgG axial recovery profiles qualitatively similar to those of albumin under normal conditions. In contrast with albumin however, the bulk of IgG and β2m uptake still occurs in S1 under nephrotic conditions. Overall, our model provides a kinetic rationale for why tubular proteinuria can occur even though a large excess in potential PT uptake capacity exists, and suggests testable predictions to expand our understanding of the recovery profile of filtered proteins along the PT. Abstract figure legend. Data from mouse models and from cultured proximal tubule (PT) cells were used to create a mathematical model that predicts the uptake profile of albumin and other filtered ligands along the mouse PT in normal and nephrotic states. The distinct contributions of cubilin receptors (magenta), megalin receptors (green), and fluid phase uptake (blue) to total albumin retrieval (black) in S1, S2, and S3 subsegments of the PT are delineated. Under normal conditions, albumin is primarily recovered in the S1 segment by cubilin, whereas the majority is retrieved in S2 under nephrotic conditions. Other proteins exhibit strikingly different uptake profiles. Our model explains how the distribution and capacity of high-affinity and low-affinity uptake pathways enable uptake of albumin over a broad range of filtered concentrations, and how tubular proteinuria can occur despite a large excess in potential PT uptake capacity. Created with BioRender.com. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Aurélie Edwards
- Department of Biomedical Engineering, Boston University, Boston, MA, 02215, USA
| | - Kimberly R Long
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Catherine J Baty
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Katherine E Shipman
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
| | - Ora A Weisz
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA
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21
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Funahashi Y, Ikeda M, Wakasaki R, Chowdhury S, Groat T, Zeppenfeld D, Hutchens MP. Renal injury in cardiorenal syndrome type 1 is mediated by albumin. Physiol Rep 2022; 10:e15173. [PMID: 35150207 PMCID: PMC8838648 DOI: 10.14814/phy2.15173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/22/2021] [Accepted: 01/02/2022] [Indexed: 11/24/2022] Open
Abstract
Cardiorenal syndrome type 1 (CRS‐1) acute kidney injury (AKI) is a critical complication of acute cardiovascular disease but is poorly understood. AKI induces acute albuminuria. As chronic albuminuria is associated with worsening kidney disease and albumin has been implicated in tubular epithelial injury, we investigated whether albumin participates in CRS‐1, and whether CRS‐1 alters renal albumin handling. We report the role of albumin in in vivo and in vitro CRS‐1 models. An established translational model, cardiac arrest and cardiopulmonary resuscitation (CA/CPR) induced severe acute albuminuria which correlated with tubular epithelial cell death. In vivo microscopy demonstrated CA/CPR‐induced glomerular filtration of exogenous albumin, while administration of exogenous albumin after CA/CPR worsened AKI compared to iso‐oncotic control. Increased albumin signal was observed in the proximal tubules of CA/CPR mice compared to sham. Comparison of albumin flux from tubular lumen to epithelial cells revealed saturated albumin transport within minutes of albumin injection after CA/CPR. In vitro, HK2 cells (human kidney tubular epithelial cells), exposed to oxygen‐glucose deprivation were injured by albumin in a dose dependent fashion. This interference was unchanged by the tubular endocytic receptor megalin. In conclusion, CRS‐1 alters albumin filtration and tubular uptake, leading to increased tubular exposure to albumin, which is injurious to tubular epithelial cells, worsening AKI. Our findings shed light on the pathophysiology of renal albumin and may guide interventions such as albumin resuscitation to improve CRS‐1 outcomes. This investigation may have important translational relevance for patients that receive exogenous albumin as part of their CRS‐1 treatment regimen.
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Affiliation(s)
- Yoshio Funahashi
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Mizuko Ikeda
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Rumie Wakasaki
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Sheuli Chowdhury
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Tahnee Groat
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Douglas Zeppenfeld
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Michael P Hutchens
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA.,Operative Care Division, Portland Veterans Affairs Medical Center, Portland, Oregon, USA
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22
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Ballermann BJ, Nyström J, Haraldsson B. The Glomerular Endothelium Restricts Albumin Filtration. Front Med (Lausanne) 2021; 8:766689. [PMID: 34912827 PMCID: PMC8667033 DOI: 10.3389/fmed.2021.766689] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/05/2021] [Indexed: 12/29/2022] Open
Abstract
Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will hopefully lead to pharmacological interventions that specifically target this important structure.
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Affiliation(s)
| | - Jenny Nyström
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Börje Haraldsson
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
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23
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Hoffmann N, Peters J. Functions of the (pro)renin receptor (Atp6ap2) at molecular and system levels: pathological implications in hypertension, renal and brain development, inflammation, and fibrosis. Pharmacol Res 2021; 173:105922. [PMID: 34607004 DOI: 10.1016/j.phrs.2021.105922] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/16/2021] [Accepted: 09/29/2021] [Indexed: 12/13/2022]
Abstract
The (pro)renin receptor [(P)RR, Atp6ap2] was initially discovered as a membrane-bound binding partner of prorenin and renin. A soluble (P)RR has additional paracrine effects and is involved in metabolic syndrome and kidney damage. Meanwhile it is clear that most of the effects of the (P)RR are independent of prorenin. In the kidney, (P)RR plays an important role in renal dysfunction by activating proinflammatory and profibrotic molecules. In the brain, (P)RR is expressed in cardiovascular regulatory nuclei and is linked to hypertension. (P)RR is known to be an essential component of the v-ATPase as a key accessory protein and plays an important role in kidney, brain and heart via regulating the pH of the extracellular space and intracellular compartments. V-ATPase and (P)RR together act on WNT and mTOR signalling pathways, which are responsible for cellular homeostasis and autophagy. (P)RR through its role in v-ATPase assembly and function is also important for fast recycling endocytosis by megalin. In the kidney, megalin together with v-ATPase and (P)RR is crucial for endocytic uptake of components of the RAS and their intracellular processing. In the brain, (P)RR, v-ATPases and megalin are important regulators both during development and in the adult. All three proteins are associated with diseases such as XLMR, XMRE, X-linked parkinsonism and epilepsy, cognitive disorders with Parkinsonism, spasticity, intellectual disability, and Alzheimer's Disease which are characterized by impaired neuronal function and/or neuronal loss. The present review focusses on the relevant effects of Atp6ap2 without assigning them necessarily to the RAS. Mechanistically, many effects can be well explained by the role of Atp6ap2 for v-ATPase assembly and function. Furthermore, application of a soluble (P)RR analogue as new therapeutic option is discussed.
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Affiliation(s)
- Nadin Hoffmann
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15A, 17475, Greifswald, Germany
| | - Jörg Peters
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15A, 17475, Greifswald, Germany.
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24
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Matsushita K, Mori K, Saritas T, Eiwaz MB, Funahashi Y, Nickerson MN, Hebert JF, Munhall AC, McCormick JA, Yanagita M, Hutchens MP. Cilastatin Ameliorates Rhabdomyolysis-induced AKI in Mice. J Am Soc Nephrol 2021; 32:2579-2594. [PMID: 34341182 PMCID: PMC8722809 DOI: 10.1681/asn.2020030263] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 06/17/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Rhabdomyolysis, the destruction of skeletal muscle, is a significant cause of AKI and death in the context of natural disaster and armed conflict. Rhabdomyolysis may also initiate CKD. Development of specific pharmacologic therapy is desirable because supportive care is nearly impossible in austere environments. Myoglobin, the principal cause of rhabdomyolysis-related AKI, undergoes megalin-mediated endocytosis in proximal tubule cells, a process that specifically injures these cells. METHODS To investigate whether megalin is protective in a mouse model of rhabdomyolysis-induced AKI, we used male C57BL/6 mice and mice (14-32 weeks old) with proximal tubule-specific deletion of megalin. We used a well-characterized rhabdomyolysis model, injection of 50% glycerol in normal saline preceded by water deprivation. RESULTS Inducible proximal tubule-specific deletion of megalin was highly protective in this mouse model of rhabdomyolysis-induced AKI. The megalin knockout mice demonstrated preserved GFR, reduced proximal tubule injury (as indicated by kidney injury molecule-1), and reduced renal apoptosis 24 hours after injury. These effects were accompanied by increased urinary myoglobin clearance. Unlike littermate controls, the megalin-deficient mice also did not develop progressive GFR decline and persistent new proteinuria. Administration of the pharmacologic megalin inhibitor cilastatin to wild-type mice recapitulated the renoprotective effects of megalin deletion. This cilastatin-mediated renoprotective effect was dependent on megalin. Cilastatin administration caused selective proteinuria and inhibition of tubular myoglobin uptake similar to that caused by megalin deletion. CONCLUSIONS We conclude that megalin plays a critical role in rhabdomyolysis-induced AKI, and megalin interference and inhibition ameliorate rhabdomyolysis-induced AKI. Further investigation of megalin inhibition may inform translational investigation of a novel potential therapy.
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Affiliation(s)
- Katsuyuki Matsushita
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Kiyoshi Mori
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Turgay Saritas
- Division of Nephrology & Hypertension, Oregon Health & Science University, Portland, Oregon,Division of Nephrology & Hypertension, University Hospital RWTH Aachen, Aachen, Germany
| | - Mahaba B. Eiwaz
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Yoshio Funahashi
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Megan N. Nickerson
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Jessica F. Hebert
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Adam C. Munhall
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - James A. McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, Portland, Oregon
| | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan,Institute for Advanced Study of Human Biology, Kyoto University, Kyoto, Japan
| | - Michael P. Hutchens
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon,Portland Veterans Affairs Medical Center, Operative Care Division, Portland, Oregon,Correspondence: Dr. Michael P. Hutchens, Operative Care Division, Portland Veterans Affairs Medical Center R&D, 5 3710 SW US Veterans Hospital Road, Portland, OR 97239.
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25
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Feng Y, Zhong X, Ni HF, Wang C, Tang TT, Wang LT, Song KY, Tang RN, Liu H, Liu BC, Lv LL. Urinary small extracellular vesicles derived CCL21 mRNA as biomarker linked with pathogenesis for diabetic nephropathy. J Transl Med 2021; 19:355. [PMID: 34404433 PMCID: PMC8371892 DOI: 10.1186/s12967-021-03030-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 08/07/2021] [Indexed: 01/06/2023] Open
Abstract
Background Diabetic nephropathy (DN) is a leading cause of renal failure, whereas the effective and early diagnostic biomarkers are still lacking. Methods Fourteen cytokines and chemokines mRNA were detected in urinary extracellular vesicles (EVs) from the screening cohort including 4 healthy controls (HC), 4 diabetes mellitus (DM) and 4 biopsy-proven DN patients, and was validated in another 16 HC and 15 DM and 28 DN patients. Correlation analysis was performed between the candidate biomarkers and clinic parameters as well as kidney histological changes. The findings were also confirmed in DN rat model with single injection of STZ. Results The number of small EVs secreted in urine was increased in DN patients compared to DM patients and healthy controls, with expression of AQP1 (a marker of proximal tubules) and AQP2 (a marker of distal/collecting tubules). Small EVs derived CCL21 mRNA increased significantly in DN patients and correlated with level of proteinuria and eGFR. Interestingly, elevated CCL21 mRNA from urine small EVs was observed in DN patients with normal renal function and could discriminate early DN patients from DM more efficiently compared to eGFR and proteinuria. CCL21 also showed an accurate diagnostic ability in distinguishing incipient from overt DN. Histologically, CCL21 mRNA expression increased progressively with the deterioration of tubulointerstitial inflammation and showed the highest level in nodular sclerosis group (class III) in DN patients. Remarkable infiltration of CD3 positive T cells including both CD4 and CD8 positive T cell population were observed in DN patients with high-CCL21 expression. Besides, accumulation of CD3 positive T cells correlated with level of urinary small EVs derived CCL21 and co-localized with CCL21 in the tubulointerstitium in DN patients. Finally, the correlation of CCL21 expression in renal cortex and urinary small EVs was confirmed in STZ-induced DN rat model. Conclusions Urinary small EVs derived CCL21 mRNA may serve as early biomarker for identifying DN linked with pathogenesis. CCL21 mRNA mediated T cell infiltration may constitute the key mechanism of chronic inflammation in DN.
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Affiliation(s)
- Ye Feng
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Xin Zhong
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Hai-Feng Ni
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Cui Wang
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Tao-Tao Tang
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Li-Ting Wang
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Kai-Yun Song
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Ri-Ning Tang
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Hong Liu
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Bi-Cheng Liu
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China
| | - Lin-Li Lv
- Institute of Nephrology, Zhongda Hospital, Southeast University School of Medicine, 87 Ding Jia Qiao Road, Nanjing, 210009, Jiangsu, China.
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26
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Abstract
Diabetes mellitus is a disease of dysregulated blood glucose homeostasis. The current pandemic of diabetes is a significant driver of patient morbidity and mortality, as well as a major challenge to healthcare systems worldwide. The global increase in the incidence of diabetes has prompted researchers to focus on the different pathogenic processes responsible for type 1 and type 2 diabetes. Similarly, increased morbidity due to diabetic complications has accelerated research to uncover pathological changes causing these secondary complications. Albuminuria, or protein in the urine, is a well-recognised biomarker and risk factor for renal and cardiovascular disease. Albuminuria is a mediator of pathological abnormalities in diabetes-associated conditions such as nephropathy and atherosclerosis. Clinical screening and diagnosis of diabetic nephropathy is chiefly based on the presence of albuminuria. Given the ease in measuring albuminuria, the potential of using albuminuria as a biomarker of cardiovascular diseases is gaining widespread interest. To assess the benefits of albuminuria as a biomarker, it is important to understand the association between albuminuria and cardiovascular disease. This review examines our current understanding of the pathophysiological mechanisms involved in both forms of diabetes, with specific focus on the link between albuminuria and specific vascular complications of diabetes.
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Affiliation(s)
- Pappitha Raja
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, Belfast, Northern Ireland, BT9 7BL, UK
| | - Alexander P Maxwell
- Nephrology Research, Centre for Public Health, Queen's University of Belfast, Northern Ireland Regional Nephrology Unit, Belfast City Hospital, Belfast, Northern Ireland, UK
| | - Derek P Brazil
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, 97 Lisburn Road, Belfast, Northern Ireland, BT9 7BL, UK.
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27
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Reduced urinary excretion of neutrophil gelatinase-associated lipocalin as a risk factor for recurrence of febrile urinary tract infection in children. Pediatr Nephrol 2021; 36:1473-1479. [PMID: 33411073 DOI: 10.1007/s00467-020-04863-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 10/16/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND This study aimed to test the hypothesis that reduced urinary excretions of neutrophil gelatinase-associated lipocalin (NGAL) predispose children to recurrence of febrile urinary tract infection (fUTI). METHODS Subjects were 38 children diagnosed with fUTI. To examine risk factors for recurrence of fUTI, the subjects were divided into a non-recurrent group and a recurrent group according to the presence or absence of fUTI over 3 years since the first episode. We measured the urinary NGAL levels in patients with fUTI at the non-infected stage in addition to age-matched healthy control children. RESULTS In a multiple logistic regression analysis, significant differences between the groups were not observed for age, sex, the prevalence of kidney scarring and bladder bowel dysfunction, urinary β2-microglobulin/creatinine (Cr) level, and serum levels of Cr and Cystatin C, while the recurrent group had significantly more cases with grade III or higher vesicoureteral reflux (p < 0.01). Furthermore, the urinary NGAL/Cr in the recurrent group (median, 3.60 μg/gCr) was significantly lower than that in the non-recurrent group (median, 16.47 μg/gCr; p < 0.01), and age-matched healthy control children (median, 14.14 μg/gCr; p < 0.05). The area under the receiver operating characteristic curve of NGAL/Cr was 0.86 for predicting recurrence of fUTI. A cut-off value of 11.59 μg/gCr had the best accuracy to predict recurrent fUTI yielding a specificity of 78% and a sensitivity of 93%. CONCLUSIONS Reduced levels of urinary NGAL, which protects against urinary infection, are a risk factor for recurrence of fUTI and could serve as a biomarker.
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28
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Bryniarski MA, Zhao B, Chaves LD, Mikkelsen JH, Yee BM, Yacoub R, Shen S, Madsen M, Morris ME. Immunoglobulin G Is a Novel Substrate for the Endocytic Protein Megalin. AAPS JOURNAL 2021; 23:40. [PMID: 33677748 DOI: 10.1208/s12248-021-00557-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/07/2021] [Indexed: 11/30/2022]
Abstract
Therapeutic immunoglobulin G (IgG) antibodies comprise the largest class of protein therapeutics. Several factors that influence their overall disposition have been well-characterized, including target-mediated mechanics and convective flow. What remains poorly defined is the potential for non-targeted entry into various tissues or cell types by means of uptake via cell surface receptors at those sites. Megalin and cubilin are large endocytic receptors whose cooperative function plays important physiological roles at the tissues in which they are expressed. One such example is the kidney, where loss of either results in significant declines in proximal tubule protein reabsorption. Due to their diverse ligand profile and broad tissue expression, megalin and cubilin represent potential candidates for receptor-mediated uptake of IgG into various epithelia. Therefore, the objective of the current work was to determine if IgG was a novel ligand of megalin and/or cubilin. Direct binding was measured for human IgG with both megalin and the cubilin/amnionless complex. Additional work focusing on the megalin-IgG interaction was then conducted to build upon these findings. Cell uptake studies using megalin ligands for competitive inhibition or proximal tubule cells stably transduced with megalin-targeted shRNA constructs supported a role for megalin in the endocytosis of human IgG. Furthermore, a pharmacokinetic study using transgenic mice with a kidney-specific mosaic knockout of megalin demonstrated increased urinary excretion of human IgG in megalin knockout mice when compared to wild-type controls. These findings indicate that megalin is capable of binding and internalizing IgG via a high affinity interaction.
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Affiliation(s)
- Mark A Bryniarski
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 445 Pharmacy Building, Buffalo, New York, 14214-8033, USA
| | - Bei Zhao
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 445 Pharmacy Building, Buffalo, New York, 14214-8033, USA
| | - Lee D Chaves
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 445 Pharmacy Building, Buffalo, New York, 14214-8033, USA.,Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | | | - Benjamin M Yee
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 445 Pharmacy Building, Buffalo, New York, 14214-8033, USA
| | - Rabi Yacoub
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 445 Pharmacy Building, Buffalo, New York, 14214-8033, USA
| | - Mette Madsen
- Department of Biomedicine, Aarhus University, 8000, Aarhus C., Denmark
| | - Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 445 Pharmacy Building, Buffalo, New York, 14214-8033, USA.
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29
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Duan S, Lu F, Song D, Zhang C, Zhang B, Xing C, Yuan Y. Current Challenges and Future Perspectives of Renal Tubular Dysfunction in Diabetic Kidney Disease. Front Endocrinol (Lausanne) 2021; 12:661185. [PMID: 34177803 PMCID: PMC8223745 DOI: 10.3389/fendo.2021.661185] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 05/21/2021] [Indexed: 12/29/2022] Open
Abstract
Over decades, substantial progress has been achieved in understanding the pathogenesis of proteinuria in diabetic kidney disease (DKD), biomarkers for DKD screening, diagnosis, and prognosis, as well as novel hypoglycemia agents in clinical trials, thereby rendering more attention focused on the role of renal tubules in DKD. Previous studies have demonstrated that morphological and functional changes in renal tubules are highly involved in the occurrence and development of DKD. Novel tubular biomarkers have shown some clinical importance. However, there are many challenges to transition into personalized diagnosis and guidance for individual therapy in clinical practice. Large-scale clinical trials suggested the clinical relevance of increased proximal reabsorption and hyperfiltration by sodium-glucose cotransporter-2 (SGLT2) to improve renal outcomes in patients with diabetes, further promoting the emergence of renal tubulocentric research. Therefore, this review summarized the recent progress in the pathophysiology associated with involved mechanisms of renal tubules, potential tubular biomarkers with clinical application, and renal tubular factors in DKD management. The mechanism of kidney protection and impressive results from clinical trials of SGLT2 inhibitors were summarized and discussed, offering a comprehensive update on therapeutic strategies targeting renal tubules.
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30
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Otomo H, Nara M, Kato S, Shimizu T, Suganuma Y, Sato T, Morii T, Yamada Y, Fujita H. Sodium-glucose cotransporter 2 inhibition attenuates protein overload in renal proximal tubule via suppression of megalin O-GlcNacylation in progressive diabetic nephropathy. Metabolism 2020; 113:154405. [PMID: 33069809 DOI: 10.1016/j.metabol.2020.154405] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/04/2020] [Accepted: 10/12/2020] [Indexed: 12/16/2022]
Abstract
AIMS The crosstalk between sodium-glucose cotransporter 2 (SGLT2) inhibition and a membrane-associated endocytic receptor megalin function involved in renal proximal tubular protein overload in progressive diabetic nephropathy (DN) is uncertain. Here, we determined whether SGLT2 inhibition affects megalin endocytic function through suppressing its O-linked β-N-acetylglucosamine modification (O-GlcNAcylation) and protects the diabetic kidney from protein overload. MATERIALS AND METHOD We treated 8-week-old male non-obese and hypoinsulinemic KK/Ta-Ins2Akita (KK/Ta-Akita) mice which develop progressive DN with an SGLT2 inhibitor ipragliflozin or insulin for 6 weeks, and investigated the endocytic function (proximal tubular protein reabsorption), renal expression and O-GlcNAcylation of megalin along with their effects on renal phenotypes including histology and biochemical markers. RESULTS The treatment with ipragliflozin, but not insulin, suppressed megalin O-GlcNAcylation and accelerated its internalization, resulting in reduction in proximal tubular reabsorption of the highly filtered plasma proteins such as albumin and neutrophil gelatinase-associated lipocalin. These alterations following the ipragliflozin treatment contributed to amelioration of proximal tubular protein overload, mitochondrial morphological abnormality, and renal oxidative stress and tubulointerstitial fibrosis. CONCLUSIONS The present study provides a novel crosstalk mechanism between SGLT2 inhibition and megalin underlying the potential renal benefits of SGLT2 inhibition in DN.
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Affiliation(s)
- Hitomi Otomo
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Mitsuhiko Nara
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Shunsuke Kato
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Tatsunori Shimizu
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Yumi Suganuma
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Takehiro Sato
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Tsukasa Morii
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Yuichiro Yamada
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan
| | - Hiroki Fujita
- Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan.
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Fujimoto D, Kuwabara T, Hata Y, Umemoto S, Kanki T, Nishiguchi Y, Mizumoto T, Hayata M, Kakizoe Y, Izumi Y, Takahashi S, Mukoyama M. Suppressed ER-associated degradation by intraglomerular cross talk between mesangial cells and podocytes causes podocyte injury in diabetic kidney disease. FASEB J 2020; 34:15577-15590. [PMID: 32996639 DOI: 10.1096/fj.202000078rr] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 09/14/2020] [Accepted: 09/21/2020] [Indexed: 12/21/2022]
Abstract
Mesangial lesions and podocyte injury are essential manifestations of the progression of diabetic kidney disease (DKD). Although cross-communication between mesangial cells (MCs) and podocytes has recently been suggested by the results of single-nucleus RNA sequencing analyses, the molecular mechanisms and role in disease progression remain elusive. Our cDNA microarray data of diabetic mouse glomeruli suggested the involvement of endoplasmic reticulum (ER) stress in DKD pathophysiology. In vitro experiments revealed the suppression of the ER-associated degradation (ERAD) pathway and induction of apoptosis in podocytes that were stimulated with the supernatant of MCs cultured in high glucose conditions. In diabetic mice, ERAD inhibition resulted in exacerbated albuminuria, increased apoptosis in podocytes, and reduced nephrin expression associated with the downregulation of ERAD-related biomolecules. Flow cytometry analysis of podocytes isolated from MafB (a transcription factor known to be expressed in macrophages and podocytes)-GFP knock-in mice revealed that ERAD inhibition resulted in decreased nephrin phosphorylation. These findings suggest that an intraglomerular cross talk between MCs and podocytes can inhibit physiological ERAD processes and suppress the phosphorylation of nephrin in podocytes, which thereby lead to podocyte injury under diabetic conditions. Therapeutic intervention of the ERAD pathway through the cross talk between these cells is potentially a novel strategy for DKD.
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Affiliation(s)
- Daisuke Fujimoto
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Takashige Kuwabara
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yusuke Hata
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Shuro Umemoto
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Tomoko Kanki
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yoshihiko Nishiguchi
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Teruhiko Mizumoto
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Manabu Hayata
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yutaka Kakizoe
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yuichiro Izumi
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Satoru Takahashi
- Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Masashi Mukoyama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
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Kukida M, Sawada H, Daugherty A, Lu HS. Megalin: A bridge connecting kidney, the renin-angiotensin system, and atherosclerosis. Pharmacol Res 2020; 151:104537. [PMID: 31707037 PMCID: PMC6980733 DOI: 10.1016/j.phrs.2019.104537] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/05/2019] [Indexed: 01/21/2023]
Abstract
Megalin is a member of the low-density lipoprotein receptor superfamily. It has been recognized as an endocytic receptor for a large spectrum of ligands. As a consequence, megalin regulates homeostasis of many molecules and affects multiple physiological and pathophysiological functions. The renin-angiotensin system is a hormonal system. A number of studies have reported contributions of the renin-angiotensin system to atherosclerosis. There is evolving evidence that megalin is a regulator of the renin-angiotensin system, and contributes to atherosclerosis. This brief review provides contemporary insights into effects of megalin on renal functions, the renin-angiotensin system, and atherosclerosis.
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Affiliation(s)
- Masayoshi Kukida
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Hisashi Sawada
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Alan Daugherty
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Hong S Lu
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA.
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Polesel M, Hall AM. Axial differences in endocytosis along the kidney proximal tubule. Am J Physiol Renal Physiol 2019; 317:F1526-F1530. [DOI: 10.1152/ajprenal.00459.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The proximal tubule (PT) reabsorbs filtered proteins via receptor-mediated endocytosis to prevent energetically inefficient wasting in the urine. Recent intravital imaging studies have suggested that protein reabsorption occurs in early (S1) segments, which have a very high capacity. In contrast, uptake of fluid phase substrates also occurs in distal (S2) segments. In this article, we will review these findings and their implications for understanding integrated proximal tubular function, patterns of damage caused by endocytosed toxins, and the origins of proteinuria. We will also discuss whether compensatory downstream increases in protein uptake might occur in disease states, and the environmental factors that could drive these changes.
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Affiliation(s)
| | - Andrew M. Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
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Wang F, Huang LP, Dai YY, Huang M, Jiang W, Ye LP, Zhu QX. Terminal complement complex C5b-9 reduced megalin and cubilin-mediated tubule proteins uptake in a mouse model of trichloroethylene hypersensitivity syndrome. Toxicol Lett 2019; 317:110-119. [PMID: 31618666 DOI: 10.1016/j.toxlet.2019.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 09/11/2019] [Accepted: 10/08/2019] [Indexed: 12/11/2022]
Abstract
Trichloroethylene (TCE), a commonly used industrial solvent and degreasing agent, is known to cause trichloroethylene hypersensitivity syndrome (THS) with multi-system damage, including skin, liver and kidney. Clinical evidence have shown that the kidney injury occurs in THS and our previous studies suggested that the terminal complement complex C5b-9 deposited in impaired renal tubules induced by TCE with unclear mechanisms. In the present study, we questioned whether activation of the complement system with renal deposition of C5b-9 contributes to TCE-induced kidney injury in THS. We established a BALB/c mouse model of TCE sensitization with or without pretreatment of exogenous CD59, a C5b-9 inhibitory protein. H&E staining, PAS staining, and biochemical detection of urinary proteins were performed to assess renal function. Deposition of C5b-9 and expression of CD59 were evaluated by immunohistochemistry. Sub-lytic effects of C5b-9 in tubular epithelial cells were assessed by lactate dehydrogenase (LDH) cytotoxicity assay. Expression of endocytosis receptors megalin and cubilin on proximal tubules were assessed by immunofluorescence and qRT-PCR. We found that TCE sensitization induced structural and functional changes of renal tubules in mice, associated with the deposition of sub-lytic C5b-9 on proximal tubular epithelial cells. TCE sensitization decreased proximal tubule uptake of filtered proteins and renal expression of megalin and cubilin, phenotypes that were attenuated by pretreatment with exogenous CD59. Overall, our findings reveal a novel mechanism underlying sub-lytic C5b-9 acting on megalin and cubilin, contributes to the renal tubules damage by TCE exposure.
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Affiliation(s)
- Feng Wang
- Department of Dermatology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China; Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, Anhui, China
| | - Li-Ping Huang
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Yu-Ying Dai
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Meng Huang
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Wei Jiang
- Department of Occupational Health and Environmental Health, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Liang-Ping Ye
- Department of Dermatology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China
| | - Qi-Xing Zhu
- Department of Dermatology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China; Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, Anhui, China.
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Nagasu H, Sogawa Y, Kidokoro K, Itano S, Yamamoto T, Satoh M, Sasaki T, Suzuki T, Yamamoto M, Wigley WC, Proksch JW, Meyer CJ, Kashihara N. Bardoxolone methyl analog attenuates proteinuria-induced tubular damage by modulating mitochondrial function. FASEB J 2019; 33:12253-12263. [PMID: 31431054 PMCID: PMC6902727 DOI: 10.1096/fj.201900217r] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Multiple clinical studies have shown that bardoxolone methyl, a potent activator of nuclear factor erythroid 2–related factor 2 (Nrf2), is effective in increasing glomerular filtration rate in patients with chronic kidney disease. However, whether an Nrf2 activator can protect tubules from proteinuria-induced tubular damage via anti-inflammatory and antioxidative stress mechanisms is unknown. Using an Institute of Cancer Research–derived glomerulonephritis (ICGN) mouse model of nephrosis, we examined the effects of dihydro-CDDO-trifluoroethyl amide (dh404), a rodent-tolerable bardoxolone methyl analog, in protecting the tubulointerstitium; dh404 markedly suppressed tubular epithelial cell damage in the renal interstitium of ICGN mice. The tubular epithelial cells of ICGN mice showed a decrease in the size and number of mitochondria, as well as the breakdown of the crista structure, whereas the number and ultrastructure of mitochondria were maintained by the dh404 treatment. To further determine the effect of dh404 on mitochondrial function, we used human proximal tubular cells in vitro. Stimulation with albumin and free fatty acid increased mitochondrial reactive oxygen species (ROS). However, dh404 administration diminished mitochondrial ROS. Our data show that dh404 significantly reduced proteinuria-induced tubular cell mitochondrial damage, suggesting that improved redox balance and mitochondrial function and suppression of inflammation underlie the cytoprotective mechanism of Nrf2 activators, including bardoxolone methyl, in diabetic kidney disease.—Nagasu, H., Sogawa, Y., Kidokoro, K., Itano, S., Yamamoto, T., Satoh, M., Sasaki, T., Suzuki, T., Yamamoto, M., Wigley, W. C., Proksch, J. W., Meyer, C. J., Kashihara, N. Bardoxolone methyl analog attenuates proteinuria-induced tubular damage by modulating mitochondrial function.
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Affiliation(s)
- Hajime Nagasu
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Yuji Sogawa
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Kengo Kidokoro
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Seiji Itano
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Toshiya Yamamoto
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Minoru Satoh
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Tamaki Sasaki
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Takafumi Suzuki
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | | | | | | | - Naoki Kashihara
- Department of Nephrology and Hypertension, Kawasaki Medical School, Kurashiki, Okayama, Japan
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36
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Wakasaki R, Matsushita K, Golgotiu K, Anderson S, Eiwaz MB, Orton DJ, Han SJ, Lee HT, Smith RD, Rodland KD, Piehowski PD, Hutchens MP. Glomerular filtrate proteins in acute cardiorenal syndrome. JCI Insight 2019; 4:122130. [PMID: 30829647 DOI: 10.1172/jci.insight.122130] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 01/14/2019] [Indexed: 12/12/2022] Open
Abstract
Acute cardiorenal syndrome (CRS-1) is a morbid complication of acute cardiovascular disease. Heart-to-kidney signals transmitted by "cardiorenal connectors" have been postulated, but investigation into CRS-1 has been limited by technical limitations and a paucity of models. To address these limitations, we developed a translational model of CRS-1, cardiac arrest and cardiopulmonary resuscitation (CA/CPR), and now report findings from nanoscale mass spectrometry proteomic exploration of glomerular filtrate 2 hours after CA/CPR or sham procedure. Filtrate acquisition was confirmed by imaging, molecular weight and charge distribution, and exclusion of protein specific to surrounding cells. Filtration of proteins specific to the heart was detected following CA/CPR and confirmed with mass spectrometry performed using urine collections from mice with deficient tubular endocytosis. Cardiac LIM protein was a CA/CPR-specific filtrate component. Cardiac arrest induced plasma release of cardiac LIM protein in mice and critically ill human cardiac arrest survivors, and administration of recombinant cardiac LIM protein to mice altered renal function. These findings demonstrate that glomerular filtrate is accessible to nanoscale proteomics and elucidate the population of proteins filtered 2 hours after CA/CPR. The identification of cardiac-specific proteins in renal filtrate suggests a novel signaling mechanism in CRS-1. We expect these findings to advance understanding of CRS-1.
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Affiliation(s)
- Rumie Wakasaki
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Katsuyuki Matsushita
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Kirsti Golgotiu
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Sharon Anderson
- Operative Care Division and Research and Development Division, Portland Veterans Affairs Medical Center, Portland, Oregon, USA.,Division of Nephrology and Hypertension, Oregon Health & Science University, Portland, Oregon, USA
| | - Mahaba B Eiwaz
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Daniel J Orton
- Pacific Northwest National Laboratory, Environmental and Biological Services Division, Richland, Washington, USA
| | - Sang Jun Han
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York, USA
| | - H Thomas Lee
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York, USA
| | - Richard D Smith
- Pacific Northwest National Laboratory, Environmental and Biological Services Division, Richland, Washington, USA
| | - Karin D Rodland
- Pacific Northwest National Laboratory, Environmental and Biological Services Division, Richland, Washington, USA
| | - Paul D Piehowski
- Pacific Northwest National Laboratory, Environmental and Biological Services Division, Richland, Washington, USA
| | - Michael P Hutchens
- Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon, USA.,Operative Care Division and Research and Development Division, Portland Veterans Affairs Medical Center, Portland, Oregon, USA
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Yamada R, Okawa T, Matsuo K, Suzuki M, Mori N, Mori K. Renal-limited thrombotic microangiopathy after switching from bevacizumab to ramucirumab: a case report. BMC Nephrol 2019; 20:14. [PMID: 30634936 PMCID: PMC6329058 DOI: 10.1186/s12882-018-1194-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/21/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND It is well known that vascular endothelial growth factor (VEGF) inhibitors can cause proteinuria. The incidence of proteinuria is high for bevacizumab, a humanized monoclonal antibody directed against VEGF, but the range of proteinuria rarely becomes nephrotic (2.2% occurrence according to a meta-analysis). In such cases, renal pathology shows thrombotic microangiopathy (TMA). Ramucirumab, anti-VEGF receptor 2 (VEGFR2) monoclonal antibody, can also cause proteinuria, but it is not yet reported whether the drug may induce TMA. CASE PRESENTATION Here, we report a case who immediately developed TMA by ramucirumab after multiple courses of bevacizumab treatment. This is the first case of pathologically-proved TMA by ramucirumab. After cessation of the drug, symptoms of TMA improved gradually. CONCLUSIONS This case demonstrates that not only blockade of VEGF but also VEGFR2 antagonism may result in TMA, which is a rare but life-threatening complication of cancer treatment drug.
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Affiliation(s)
- Ryo Yamada
- Department of Nephrology, Shizuoka General Hospital, Shizuoka, 420-8527, Japan
| | - Takao Okawa
- Department of Nephrology, Shizuoka General Hospital, Shizuoka, 420-8527, Japan
| | - Ken Matsuo
- Department of Nephrology, Shizuoka General Hospital, Shizuoka, 420-8527, Japan
| | - Makoto Suzuki
- Department of Pathology, Shizuoka General Hospital, Shizuoka, 420-8527, Japan
| | - Noriko Mori
- Department of Nephrology, Shizuoka General Hospital, Shizuoka, 420-8527, Japan
| | - Kiyoshi Mori
- Department of Nephrology, Shizuoka General Hospital, Shizuoka, 420-8527, Japan.
- Department of Nephrology and Kidney Research, Center for Public Health, Shizuoka General Hospital, Shizuoka, 420-8527, Japan.
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38
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Histamine and diabetic nephropathy: an up-to-date overview. Clin Sci (Lond) 2019; 133:41-54. [PMID: 30606813 DOI: 10.1042/cs20180839] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/22/2018] [Accepted: 12/10/2018] [Indexed: 01/10/2023]
Abstract
The classification of diabetic nephropathy (DN) as a vascular complication of diabetes makes the possible involvement of histamine, an endogenous amine that is well known for its vasoactive properties, an interesting topic for study. The aim of the present review is to provide an extensive overview of the possible involvement of histamine in the onset and progression of DN. The evidence collected on the role of histamine in kidney function together with its well-known pleiotropic action suggest that this amine may act simultaneously on glomerular hyperfiltration, tubular inflammation, fibrosis development and tubular hypertrophy.
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39
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Tian D, Shi X, Zhao Y, Peng X, Zou L, Xu L, Ma Y, Wen Y, Faulhaber-Walter R, Chen L. The effect of A1 adenosine receptor in diabetic megalin loss with caspase-1/IL18 signaling. Diabetes Metab Syndr Obes 2019; 12:1583-1596. [PMID: 31695457 PMCID: PMC6717852 DOI: 10.2147/dmso.s215531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/16/2019] [Indexed: 12/18/2022] Open
Abstract
PURPOSE In our previous study, exacerbation of albuminuria was observed in A1 adenosine receptor knockout (A1AR-/-) mice with diabetic nephropathy (DN), but the mechanism was unclear. Here, we investigated the relationship of megalin loss and albuminuria, to identify the protective effect of A1AR in megalin loss associated albuminuria by inhibiting pyroptosis-related caspase-1/IL-18 signaling of DN. METHODS We successfully collected DN patients' samples and built diabetes mice models induced by streptozotocin. Megalin, cubilin, and A1AR expression were detected in kidney tissue samples from DN patients and mice through immunohistochemical and immunofluorescent staining. A1AR, caspase-1, interleukin-18 (IL-18) expression were analyzed using Western blotting in wild-type and A1AR -/- mice. Human renal proximal tubular epithelial cells (PTC) were cultured with high glucose to observe the effect of A1AR agonist and antagonist on caspase-1/IL-18 and megalin injury. RESULTS The loss of megalin, co-localized with A1AR at PTC, was associated with the level of albuminuria in diabetic patients and mice. The injury of megalin-cubilin was accompanied with the A1AR upregulation (1.30±0.1 vs 0.98±0.2, P=0.042), the caspase-1 (1.33±0.1 vs 1.0±0.2, P=0.036), and IL-18 (1.26±0.2 vs 0.96±0.2, P=0.026) signaling activation in mice with DN. More severe pathological injury, 24 hrs urine albumin excretion (170.8±4.1 μg/d vs 132.0±2.9 μg/d vs 17.9±2.8 μg/d, P<0.001) and megalin-cubilin loss were observed in A1AR -/- DN mice with more pronounced caspase-1 (1.52±0.03 vs 1.20±0.01, P=0.017) and IL-18 (1.42±0.02 vs 1.21±0.02, P=0.018) secretion. High glucose could stimulate the secretion of caspase-1 (1.72 times, P≤0.01) and IL-18 (1.64 times, P≤0.01), which was abolished by A1AR agonist and aggravated by A1AR antagonist. CONCLUSION A1AR played a protective role in proximal tubular megalin loss associated albuminuria by inhibiting the pyroptosis-related caspase-1/IL-18 signaling in DN.
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Affiliation(s)
- Dongli Tian
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Xiaoxiao Shi
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Yumo Zhao
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Xiaoyan Peng
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Linfeng Zou
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Lubin Xu
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Ying Ma
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | - Yubin Wen
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
| | | | - Limeng Chen
- Department of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing100730, People’s Republic of China
- Correspondence: Limeng ChenDepartment of Nephrology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Road 1 Shuaifuyuan, Wangfujing Street, Beijing100730, People’s Republic of ChinaTel +86 106 915 5351Fax +86 106 915 5058Email
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Aoki S, Saito-Hakoda A, Yoshikawa T, Shimizu K, Kisu K, Suzuki S, Takagi K, Mizumoto S, Yamada S, van Kuppevelt TH, Yokoyama A, Matsusaka T, Sato H, Ito S, Sugawara A. The reduction of heparan sulphate in the glomerular basement membrane does not augment urinary albumin excretion. Nephrol Dial Transplant 2018; 33:26-33. [PMID: 28992095 DOI: 10.1093/ndt/gfx218] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 04/23/2017] [Indexed: 01/12/2023] Open
Abstract
Background Heparan sulphate proteoglycan (HSPG) is present in the glomerular basement membrane (GBM) and is thought to play a major role in the glomerular charge barrier. Reductions and structural alterations of HSPG are observed in different types of kidney diseases accompanied by proteinuria. However, their causal relations remain unknown. Methods We generated podocyte-specific exostosin-like 3 gene (Extl3) knockout mice (Extl3KO) using a Cre-loxP recombination approach. A reduction of HSPG was expected in the GBM of these mice, because EXTL3 is involved in its synthesis. Mice were separated into three groups, according to the loads on the glomeruli: a high-protein diet group, a high-protein and high-sodium diet group and a hyperglycaemic group induced by streptozotocin treatment in addition to maintenance on a high-protein and high-sodium diet. The urinary albumin:creatinine ratio was measured at 7, 11, 15 and 19 weeks of age. Renal histology was also investigated. Results Podocyte-specific expression of Cre recombinase was detected by immunohistochemistry. Moreover, immunofluorescent staining demonstrated a significant reduction of HSPG in the GBM. Electron microscopy showed irregularities in the GBM and effacement of the foot processes in Extl3KO. The values of the urinary albumin:creatinine ratio were within the range of microalbuminuria in all groups and did not significantly differ between the control mice and Extl3KO. Conclusions The reduction of HSPG in the GBM did not augment urinary albumin excretion. HSPG's anionic charge appears to contribute little to the glomerular charge barrier.
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Affiliation(s)
- Satoshi Aoki
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akiko Saito-Hakoda
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Takeo Yoshikawa
- Department of Pharmacology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kyoko Shimizu
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kiyomi Kisu
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Susumu Suzuki
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Kiyoshi Takagi
- Department of Pathology and Histotechnology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijyo University, Nagoya, Aichi, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijyo University, Nagoya, Aichi, Japan
| | - Toin H van Kuppevelt
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Atsushi Yokoyama
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Taiji Matsusaka
- Department of Molecular Life Sciences, Tokai University School of Medicine, Isehara, Kanagawa, Japan
| | - Hiroshi Sato
- Department of Clinical Pharmacology and Therapeutics, Tohoku University Graduate School of Pharmaceutical Sciences, Sendai, Miyagi, Japan
| | - Sadayoshi Ito
- Division of Nephrology, Endocrinology and Vascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
| | - Akira Sugawara
- Department of Molecular Endocrinology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
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41
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Shrestha S, Sunaga H, Hanaoka H, Yamaguchi A, Kuwahara S, Umbarawan Y, Nakajima K, Machida T, Murakami M, Saito A, Tsushima Y, Kurabayashi M, Iso T. Circulating FABP4 is eliminated by the kidney via glomerular filtration followed by megalin-mediated reabsorption. Sci Rep 2018; 8:16451. [PMID: 30401801 PMCID: PMC6219568 DOI: 10.1038/s41598-018-34902-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/28/2018] [Indexed: 01/15/2023] Open
Abstract
Circulating fatty acid binding protein 4 (FABP4), secreted from adipocytes, is a potential biomarker for metabolic and cardiovascular diseases. Circulating FABP4 levels are positively associated with adiposity and adrenergic stimulation, but negatively with renal function. In this study, we addressed the issue of how the kidney regulates clearance of circulating FABP4. Tracing study revealed remarkable accumulation of 125I-labeled FABP4 in the kidney. Exogenous FABP4 was exclusively detected in the apical membrane of proximal tubule epithelial cells (PTECs). Bilateral nephrectomy resulted in marked elevation of circulating FABP4 levels. Accelerated lipolysis by β-3 adrenergic stimulation led to a marked elevation in circulating FABP4 in mice with severe renal dysfunction. Megalin, an endocytic receptor expressed in PTECs, plays a major role in reabsorption of proteins filtered through glomeruli. Quartz-crystal microbalance study revealed that FABP4 binds to megalin. In kidney-specific megalin knockout mice, a large amount of FABP4 was excreted in urine while circulating FABP4 levels were significantly reduced. Our data suggest that circulating FABP4 is processed by the kidney via the glomerular filtration followed by megalin-mediated reabsorption. Thus, it is likely that circulating FABP4 levels are determined mainly by balance between secretion rate of FABP4 from adipocytes and clearance rate of the kidney.
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Affiliation(s)
- Suman Shrestha
- Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Hiroaki Sunaga
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Hirofumi Hanaoka
- Department of Bioimaging Information Analysis, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Aiko Yamaguchi
- Department of Bioimaging Information Analysis, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Shoji Kuwahara
- Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8585, Japan
| | - Yogi Umbarawan
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.,Department of Internal Medicine, Faculty of Medicine Universitas Indonesia, Jl. Salemba Raya No. 6, Jakarta, 10430, Indonesia
| | - Kiyomi Nakajima
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Tetsuo Machida
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Masami Murakami
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Akihiko Saito
- Department of Applied Molecular Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8585, Japan
| | - Yoshito Tsushima
- Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.,Research Program for Diagnostic and Molecular Imaging, Division of Integrated Oncology Research, Gunma University Initiative for Advanced Research (GIAR), 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Masahiko Kurabayashi
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.,Program for obesity-related cardiovascular disease, Division of Endocrinology, Metabolism and Signaling, Gunma University Initiative for Advanced Research (GIAR), 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan
| | - Tatsuya Iso
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
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42
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Schuh CD, Polesel M, Platonova E, Haenni D, Gassama A, Tokonami N, Ghazi S, Bugarski M, Devuyst O, Ziegler U, Hall AM. Combined Structural and Functional Imaging of the Kidney Reveals Major Axial Differences in Proximal Tubule Endocytosis. J Am Soc Nephrol 2018; 29:2696-2712. [PMID: 30301861 DOI: 10.1681/asn.2018050522] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/18/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The kidney proximal convoluted tubule (PCT) reabsorbs filtered macromolecules via receptor-mediated endocytosis (RME) or nonspecific fluid phase endocytosis (FPE); endocytosis is also an entry route for disease-causing toxins. PCT cells express the protein ligand receptor megalin and have a highly developed endolysosomal system (ELS). Two PCT segments (S1 and S2) display subtle differences in cellular ultrastructure; whether these translate into differences in endocytotic function has been unknown. METHODS To investigate potential differences in endocytic function in S1 and S2, we quantified ELS protein expression in mouse kidney PCTs using real-time quantitative polymerase chain reaction and immunostaining. We also used multiphoton microscopy to visualize uptake of fluorescently labeled ligands in both living animals and tissue cleared using a modified CLARITY approach. RESULTS Uptake of proteins by RME occurs almost exclusively in S1. In contrast, dextran uptake by FPE takes place in both S1 and S2, suggesting that RME and FPE are discrete processes. Expression of key ELS proteins, but not megalin, showed a bimodal distribution; levels were far higher in S1, where intracellular distribution was also more polarized. Tissue clearing permitted imaging of ligand uptake at single-organelle resolution in large sections of kidney cortex. Analysis of segmented tubules confirmed that, compared with protein uptake, dextran uptake occurred over a much greater length of the PCT, although individual PCTs show marked heterogeneity in solute uptake length and three-dimensional morphology. CONCLUSIONS Striking axial differences in ligand uptake and ELS function exist along the PCT, independent of megalin expression. These differences have important implications for understanding topographic patterns of kidney diseases and the origins of proteinuria.
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Affiliation(s)
| | | | | | - Dominik Haenni
- Institute of Anatomy.,Center for Microscopy and Image Analysis, and
| | - Alkaly Gassama
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and
| | - Natsuko Tokonami
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and
| | | | | | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and
| | - Urs Ziegler
- Center for Microscopy and Image Analysis, and
| | - Andrew M Hall
- Institute of Anatomy, .,Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
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43
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Takiyama Y, Sera T, Nakamura M, Ishizeki K, Saijo Y, Yanagimachi T, Maeda M, Bessho R, Takiyama T, Kitsunai H, Sakagami H, Fujishiro D, Fujita Y, Makino Y, Abiko A, Hoshino M, Uesugi K, Yagi N, Ota T, Haneda M. Impacts of Diabetes and an SGLT2 Inhibitor on the Glomerular Number and Volume in db/db Mice, as Estimated by Synchrotron Radiation Micro-CT at SPring-8. EBioMedicine 2018; 36:329-346. [PMID: 30322799 PMCID: PMC6197731 DOI: 10.1016/j.ebiom.2018.09.048] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/26/2018] [Accepted: 09/26/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Recent large-scale clinical studies demonstrate that sodium-glucose cotransporter 2 (SGLT2) inhibitors protect the diabetic kidney. However, clinical and animal studies have not shown the changes of the total glomeruli in the whole kidney treated with SGLT2 inhibitors. METHODS We performed computed tomography (CT) imaging on mice using synchrotron radiation to investigate the impact of luseogliflozin, a SGLT2 inhibitor, on the number and volume of glomeruli in the whole kidney. FINDINGS We did not observe a significant difference in the total glomerular number (Nglom) among mice. Luseogliflozin redistributed the number of glomeruli in different regions, accompanied by the normalization of diabetes-augmented renal volume (Vkidney). Diabetic db/db mice had a larger glomerular volume in the mid-cortex than did control db/m mice, and luseogliflozin increased the glomerular volume in all renal cortical zones of the whole kidney in db/db mice. According to the multivariate regression analysis, hemoglobin A1c level was the most relevant determinant of Vkidney, not Nglom or mean glomerular volume (Vglom), indicating that hyperglycemia induced renal (tubular) hypertrophy, but not glomerular enlargement. Luseogliflozin increased hypoxia in the juxtamedullary region, sustained upregulated renal renin expression and plasma renin activity, and failed to decrease albuminuria by downregulating megalin in db/db mice. INTERPRETATION Based on our findings, SGLT2 inhibitors may alter glomerular distribution and size in addition to their glucose-lowering effects, presumably by affecting oxygen metabolism and humoral factors. FUND: Funding for this research was provided by The Japan Society for the Promotion of Science, the Japan Diabetes Foundation, and Asahikawa Medical University.
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Affiliation(s)
- Yumi Takiyama
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan.
| | - Toshihiro Sera
- Department of Mechanical Engineering, Faculty of Engineering, Kyushu University, Japan
| | - Masanori Nakamura
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Japan
| | - Kanaki Ishizeki
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Yasuaki Saijo
- Department of Health Science, Asahikawa Medical University, Japan
| | - Tsuyoshi Yanagimachi
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Manami Maeda
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Ryoichi Bessho
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Takao Takiyama
- Department of Neurosurgery, Asahikawa Medical University, Japan
| | - Hiroya Kitsunai
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Hidemitsu Sakagami
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Daisuke Fujishiro
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Yukihiro Fujita
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Yuichi Makino
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Atsuko Abiko
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Masato Hoshino
- Research & Utilization Division, Japan Synchrotron Radiation Research Institute, Japan
| | - Kentaro Uesugi
- Research & Utilization Division, Japan Synchrotron Radiation Research Institute, Japan
| | - Naoto Yagi
- Research & Utilization Division, Japan Synchrotron Radiation Research Institute, Japan
| | - Tsuguhito Ota
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
| | - Masakazu Haneda
- Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Japan
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44
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Jiao Y, Jiang H, Lu H, Yang Y, Zhang Y, Zhang K, Liu H. Deficiency of hypoxia inducible factor-1α promoted progression of diabetic nephropathy with hypertension. Exp Ther Med 2018; 16:3658-3662. [PMID: 30233722 DOI: 10.3892/etm.2018.6621] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 07/13/2018] [Indexed: 12/19/2022] Open
Abstract
The present study was designed to investigate the effect of hypoxia inducible factor-1α (HIF-1α) on diabetic nephropathy (DN) with hypertension. HIF-1α deficient mice (Mx/HIF-1α-/-) were constructed and treated with streptozotocin (STZ) injection for hypertensive DN induction. Normal C57BL/6 mice received STZ or no treatment (normal) were considered as controls. Three days post STZ administration; body weight, fasting blood glucose (FBG), 24 h urinary albumin and systolic blood pressure (SBP) were measured weekly. Periodic acid-Schiff's staining was performed for histologic analysis of glomeruli damage. In comparison with the normal control, significant upregulation and downregulation of HIF-1α was, respectively, detected in diabetic and HIF-1α-/- mice (P<0.01). In comparison with STZ-induced diabetic mice, HIF-1α-/- + STZ mice displayed reduced body weight, and increased FBG, urinary albumin and SBP. PAS showed HIF-1α-/- + STZ mice had damaged kidney tissues, with more renal fibrosis and apparent glomerular hypertrophy. These results demonstrated that HIF-1α deficiency accelerated DN progression with increasing hypertension in mice.
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Affiliation(s)
- Yuejiang Jiao
- Department of Endocrinology, Luoyang Central Hospital Affiliated to Zhengzhou University, Luoyang, Henan 471009, P.R. China
| | - Hongwei Jiang
- Department of Endocrinology, The 1st Affiliated Hospital of Henan University of Science and Technology, Luoyang, Henan 471033, P.R. China
| | - Haibo Lu
- Department of Endocrinology, The 1st Affiliated Hospital of Henan University of Science and Technology, Luoyang, Henan 471033, P.R. China
| | - Yiping Yang
- Department of Endocrinology, Luoyang Central Hospital Affiliated to Zhengzhou University, Luoyang, Henan 471009, P.R. China
| | - Yanfang Zhang
- Department of Endocrinology, Luoyang Central Hospital Affiliated to Zhengzhou University, Luoyang, Henan 471009, P.R. China
| | - Kun Zhang
- Department of Endocrinology, The 1st Affiliated Hospital of Henan University of Science and Technology, Luoyang, Henan 471033, P.R. China
| | - Hui Liu
- Department of Endocrinology, Luoyang Central Hospital Affiliated to Zhengzhou University, Luoyang, Henan 471009, P.R. China
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45
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Silva-Aguiar RP, Bezerra NCF, Lucena MC, Sirtoli GM, Sudo RT, Zapata-Sudo G, Takiya CM, Pinheiro AAS, Dias WB, Caruso-Neves C. O-GlcNAcylation reduces proximal tubule protein reabsorption and promotes proteinuria in spontaneously hypertensive rats. J Biol Chem 2018; 293:12749-12758. [PMID: 29954945 DOI: 10.1074/jbc.ra118.001746] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 06/27/2018] [Indexed: 12/11/2022] Open
Abstract
Hypertensive individuals are at greater risk for developing chronic kidney disease (CKD). Reducing proteinuria has been suggested as a possible therapeutic approach to treat CKD. However, the mechanisms underlying the development of proteinuria in hypertensive conditions are incompletely understood. Cardiac and vascular dysfunction is associated with changes in the O-GlcNAcylation pathway in hypertensive models. We hypothesized that O-GlcNAcylation is also involved in renal damage, especially development of proteinuria, associated with hypertension. Using the spontaneously hypertensive rat (SHR) model, we observed higher renal cortex O-GlcNAcylation, glutamine-fructose aminotransferase (GFAT), and O-GlcNAc transferase (OGT) protein expression, which positively correlated with proteinuria. Interestingly, this was observed in hypertensive, but not pre-hypertensive, rats. Pharmacological inhibition of GFAT decreased renal cortex O-GlcNAcylation, proteinuria, and albuminuria in SHR. Using a proximal tubule cell line, we observed that increased O-GlcNAcylation reduced megalin surface expression and albumin endocytosis in vitro, and the effects were correlated in vivo Moreover, megalin is O-GlcNAcylated both in vitro and in vivo In conclusion, our results demonstrate a new mechanism involved in hypertension-associated proteinuria.
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Affiliation(s)
- Rodrigo Pacheco Silva-Aguiar
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Nathália C F Bezerra
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Miguel C Lucena
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Gabriela M Sirtoli
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Roberto T Sudo
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Gisele Zapata-Sudo
- Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Christina M Takiya
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Ana Acacia S Pinheiro
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Wagner Barbosa Dias
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil
| | - Celso Caruso-Neves
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21949-900, Brazil; Instituto Nacional de Ciência e Tecnologia em Medicina Regenerativa (INCT-Regenera), Rio de Janeiro 21941-902, Brazil.
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Bryniarski MA, Yee BM, Jaffri I, Chaves LD, Yu JA, Guan X, Ghavam N, Yacoub R, Morris ME. Increased megalin expression in early type 2 diabetes: role of insulin-signaling pathways. Am J Physiol Renal Physiol 2018; 315:F1191-F1207. [PMID: 29949391 DOI: 10.1152/ajprenal.00210.2018] [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] [Indexed: 02/07/2023] Open
Abstract
The megalin/cubilin complex is responsible for the majority of serum protein reclamation in the proximal tubules. The current study examined if decreases in their renal expression, along with the albumin recycling protein neonatal Fc receptor (FcRn) could account for proteinuria/albuminuria in the Zucker diabetic fatty rat model of type 2 diabetes. Immunoblots of renal cortex samples obtained at worsening disease stages demonstrated no loss in megalin, cubilin, or FcRn, even when proteinuria was measured. Additionally, early diabetic rats exhibited significantly increased renal megalin expression when compared with controls (adjusted P < 0.01). Based on these results, the ability of insulin to increase megalin was examined in a clonal subpopulation of the opossum kidney proximal tubule cell line. Insulin treatments (24 h, 100 nM) under high glucose conditions significantly increased megalin protein ( P < 0.0001), mRNA ( P < 0.0001), and albumin endocytosis. The effect on megalin expression was prevented with inhibitors against key effectors of insulin intracellular signaling, phosphatidylinositide 3-kinase and Akt. Studies using rapamycin to inhibit the mechanistic target of rapamycin complex 1 (mTORC1) resulted in a loss of insulin-induced megalin expression. However, subsequent evaluation demonstrated these effects were independent of initial mTORC1 suppression. The presented results provide insight into the expression of megalin, cubilin, and FcRn in type 2 diabetes, which may be impacted by elevated insulin and glucose. Furthermore, proximal tubule endocytic activity in early diabetics may be enhanced, a process that could have a significant role in proteinuria-induced renal damage.
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Affiliation(s)
- Mark A Bryniarski
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Benjamin M Yee
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Irum Jaffri
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Lee D Chaves
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo , New York
| | - Jin Ah Yu
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Xiaowen Guan
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Nazanin Ghavam
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
| | - Rabi Yacoub
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo , New York
| | - Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo , New York
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47
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Comprehensive renoprotective effects of ipragliflozin on early diabetic nephropathy in mice. Sci Rep 2018; 8:4029. [PMID: 29507299 PMCID: PMC5838225 DOI: 10.1038/s41598-018-22229-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 02/19/2018] [Indexed: 12/20/2022] Open
Abstract
Clinical and experimental studies have shown that sodium glucose co-transporter 2 inhibitors (SGLT2i) contribute to the prevention of diabetic kidney disease progression. In order to clarify its pharmacological effects on the molecular mechanisms underlying the development of diabetic kidney disease, we administered different doses of the SGLT2i, ipragliflozin, to type 2 diabetic mice. A high-dose ipragliflozin treatment for 8 weeks lowered blood glucose levels and reduced urinary albumin excretion. High- and low-dose ipragliflozin both inhibited renal and glomerular hypertrophy, and reduced NADPH oxidase 4 expression and subsequent oxidative stress. Analysis of glomerular phenotypes using glomeruli isolation demonstrated that ipragliflozin preserved podocyte integrity and reduced oxidative stress. Regarding renal tissue hypoxia, a short-term ipragliflozin treatment improved oxygen tension in the kidney cortex, in which SGLT2 is predominantly expressed. We then administered ipragliflozin to type 1 diabetic mice and found that high- and low-dose ipragliflozin both reduced urinary albumin excretion. In conclusion, we confirmed dose-dependent differences in the effects of ipragliflozin on early diabetic nephropathy in vivo. Even low-dose ipragliflozin reduced renal cortical hypoxia and abnormal hemodynamics in early diabetic nephropathy. In addition to these effects, high-dose ipragliflozin exerted renoprotective effects by reducing oxidative stress in tubular epithelia and glomerular podocytes.
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48
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Desideri S, Onions KL, Qiu Y, Ramnath RD, Butler MJ, Neal CR, King MLR, Salmon AE, Saleem MA, Welsh GI, Michel CC, Satchell SC, Salmon AHJ, Foster RR. A novel assay provides sensitive measurement of physiologically relevant changes in albumin permeability in isolated human and rodent glomeruli. Kidney Int 2018; 93:1086-1097. [PMID: 29433915 PMCID: PMC5912930 DOI: 10.1016/j.kint.2017.12.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/05/2017] [Accepted: 12/13/2017] [Indexed: 01/06/2023]
Abstract
Increased urinary albumin excretion is a key feature of glomerular disease but has limitations as a measure of glomerular permeability. Here we describe a novel assay to measure the apparent albumin permeability of single capillaries in glomeruli, isolated from perfused kidneys cleared of red blood cells. The rate of decline of the albumin concentration within the capillary lumen was quantified using confocal microscopy and used to calculate apparent permeability. The assay was extensively validated and provided robust, reproducible estimates of glomerular albumin permeability. These values were comparable with previous in vivo data, showing this assay could be applied to human as well as rodent glomeruli. To confirm this, we showed that targeted endothelial glycocalyx disruption resulted in increased glomerular albumin permeability in mice. Furthermore, incubation with plasma from patients with post-transplant recurrence of nephrotic syndrome increased albumin permeability in rat glomeruli compared to remission plasma. Finally, in glomeruli isolated from rats with early diabetes there was a significant increase in albumin permeability and loss of endothelial glycocalyx, both of which were ameliorated by angiopoietin-1. Thus, a glomerular permeability assay, producing physiologically relevant values with sufficient sensitivity to measure changes in glomerular permeability and independent of tubular function, was developed and validated. This assay significantly advances the ability to study biology and disease in rodent and human glomeruli.
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Affiliation(s)
- Sara Desideri
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Karen L Onions
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Yan Qiu
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Raina D Ramnath
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Matthew J Butler
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Christopher R Neal
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Matthew L R King
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Andrew E Salmon
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Moin A Saleem
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Gavin I Welsh
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | | | - Simon C Satchell
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Andrew H J Salmon
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK
| | - Rebecca R Foster
- Bristol Renal, Bristol Medical School, University of Bristol, Bristol, UK.
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49
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Ly ND, Tesch GH, Nikolic-Paterson DJ, Poronnik P. Proximal tubular epithelial cells preferentially endocytose covalently-modified albumin compared to native albumin. Nephrology (Carlton) 2017; 24:121-126. [PMID: 29240283 DOI: 10.1111/nep.13211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2017] [Indexed: 11/30/2022]
Abstract
AIM Albumin can be covalently modified at surface lysine residues and thus the circulation contains a mixture of native albumin (i.e. not modified) and albumin with varying degrees of modification. Uptake and lysosomal degradation of glomerular filtered albumin by proximal tubular cells via the megalin scavenger receptor is considered an important mechanism to limit albumin loss in the urine. However, whether this is a general mechanism of tubular uptake of albumin or if this is restricted to modified albumin is unknown. To address this question, we investigated the uptake of modified versus native albumin by proximal tubular cells. METHODS A well-characterized proximal tubular cell model of albumin uptake was used to compare the uptake of modified albumin (covalent labelling of lysine residues with fluorescent probes) to that of native recombinant human albumin (rHA) labelled with 14 C during protein synthesis (14 C-rHA). RESULTS Opossum kidney (OK) cells showed significant uptake of fluorescence-labelled albumin via an endocytosis mechanism. This uptake was inhibited by an equimolar ratio of different types of covalently modified albumin; however, purified bovine serum albumin and rHA failed to compete with the uptake of fluorescence-labelled albumin. In contrast, OK cells failed to endocytose native 14 C-rHA despite efficiently endocytosing covalently modified rHA. CONCLUSION Our studies show that OK cells preferentially endocytose covalently-modified albumin compared to native albumin. This apparent selectivity of the megalin scavenger receptor complex suggests a specific role for this pathway in the removal of modified albumin from the circulation.
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Affiliation(s)
- Nguyen Dk Ly
- School of Medical Sciences, RMIT University, Melbourne, Victoria, Australia.,Department of Nephrology, Monash Medical Centre, Melbourne, Victoria, Australia
| | - Greg H Tesch
- Department of Nephrology, Monash Medical Centre, Melbourne, Victoria, Australia.,Monash University Centre for Inflammatory Diseases, Monash Medical Centre, Melbourne, Victoria, Australia
| | - David J Nikolic-Paterson
- School of Medical Sciences, RMIT University, Melbourne, Victoria, Australia.,Department of Nephrology, Monash Medical Centre, Melbourne, Victoria, Australia.,Monash University Centre for Inflammatory Diseases, Monash Medical Centre, Melbourne, Victoria, Australia
| | - Philip Poronnik
- School of Medical Sciences and Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
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50
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Zeni L, Norden AGW, Cancarini G, Unwin RJ. A more tubulocentric view of diabetic kidney disease. J Nephrol 2017; 30:701-717. [PMID: 28840540 PMCID: PMC5698396 DOI: 10.1007/s40620-017-0423-9] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 07/22/2017] [Indexed: 12/14/2022]
Abstract
Diabetic nephropathy (DN) is a common complication of Diabetes Mellitus (DM) Types 1 and 2, and prevention of end stage renal disease (ESRD) remains a major challenge. Despite its high prevalence, the pathogenesis of DN is still controversial. Initial glomerular disease manifested by hyperfiltration and loss of glomerular size and charge permselectivity may initiate a cascade of injuries, including tubulo-interstitial disease. Clinically, 'microalbuminuria' is still accepted as an early biomarker of glomerular damage, despite mounting evidence that its predictive value for DN is questionable, and findings that suggest the proximal tubule is an important link in the development of DN. The concept of 'diabetic tubulopathy' has emerged from recent studies, and its causative role in DN is supported by clinical and experimental evidence, as well as plausible pathogenetic mechanisms. This review explores the 'tubulocentric' view of DN. The recent finding that inhibition of proximal tubule (PT) glucose transport (via SGLT2) is nephro-protective in diabetic patients is discussed in relation to the tubule's potential role in DN. Studies with a tubulocentric view of DN have stimulated alternative clinical approaches to the early detection of diabetic kidney disease. There are tubular biomarkers considered as direct indicators of injury of the proximal tubule (PT), such as N-acetyl-β-D-glucosaminidase, Neutrophil Gelatinase-Associated Lipocalin and Kidney Injury Molecule-1, and other functional PT biomarkers, such as Urine free Retinol-Binding Protein 4 and Cystatin C, which reflect impaired reabsorption of filtered proteins. The clinical application of these measurements to diabetic patients will be reviewed in the context of the need for better biomarkers for early DN.
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Affiliation(s)
- Letizia Zeni
- Department of Medical and Surgical Specialities, Radiological Sciences and Public Health, University of Brescia, Piazza del Mercato 15, 25121, Brescia, Italy.
- UCL Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK.
- Operative Unit of Nephrology, ASST Spedali Civili, Piazzale Spedali Civili 1, Brescia, Italy.
| | - Anthony G W Norden
- UCL Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK
| | - Giovanni Cancarini
- Department of Medical and Surgical Specialities, Radiological Sciences and Public Health, University of Brescia, Piazza del Mercato 15, 25121, Brescia, Italy
- Operative Unit of Nephrology, ASST Spedali Civili, Piazzale Spedali Civili 1, Brescia, Italy
| | - Robert J Unwin
- UCL Centre for Nephrology, UCL Medical School, Royal Free Campus, Rowland Hill Street, London, NW3 2PF, UK
- Cardiovascular and Metabolic Diseases iMED ECD, AstraZeneca Gothenburg, Mölndal, Sweden
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