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Kanbay M, Copur S, Guldan M, Ozbek L, Hatipoglu A, Covic A, Mallamaci F, Zoccali C. Proximal tubule hypertrophy and hyperfunction: a novel pathophysiological feature in disease states. Clin Kidney J 2024; 17:sfae195. [PMID: 39050867 PMCID: PMC11267238 DOI: 10.1093/ckj/sfae195] [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: 05/12/2024] [Indexed: 07/27/2024] Open
Abstract
The role of proximal tubules (PTs), a major component of the renal tubular structure in the renal cortex, has been examined extensively. Along with its physiological role in the reabsorption of various molecules, including electrolytes, amino acids and monosaccharides, transcellular transport of different hormones and regulation of homeostasis, pathological events affecting PTs may underlie multiple disease states. PT hypertrophy or a hyperfunctioning state, despite being a compensatory mechanism at first in response to various stimuli or alterations at tubular transport proteins, have been shown to be critical pathophysiological events leading to multiple disorders, including diabetes mellitus, obesity, metabolic syndrome and congestive heart failure. Moreover, pharmacotherapeutic agents have primarily targeted PTs, including sodium-glucose cotransporter 2, urate transporters and carbonic anhydrase enzymes. In this narrative review, we focus on the physiological role of PTs in healthy states and the current understanding of the PT pathologies leading to disease states and potential therapeutic targets.
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Affiliation(s)
- Mehmet Kanbay
- Department of Internal Medicine, Division of Nephrology, Koç University School of Medicine, Istanbul, Turkey
| | - Sidar Copur
- Department of Medicine, Koç University School of Medicine, Istanbul, Turkey
| | - Mustafa Guldan
- Department of Internal Medicine, Division of Internal Medicine, Koç University School of Medicine, Istanbul, Turkey
| | - Lasin Ozbek
- Department of Internal Medicine, Division of Internal Medicine, Koç University School of Medicine, Istanbul, Turkey
| | - Alper Hatipoglu
- Department of Internal Medicine, Division of Internal Medicine, Koç University School of Medicine, Istanbul, Turkey
| | - Adrian Covic
- Nephrology, Dialysis and Transplantation, University Grigore T Popa, Iasi, Romania
| | - Francesca Mallamaci
- Nephrology, Dialysis and Transplantation Unit, Grande Ospedale Metropolitano, Reggio Calabria, Italy
- CNR-IFC, Research Unit of Clinical Epidemiology and Physiopathology of Renal Diseases and Hypertension, Institute of Clinical Physiology, Reggio Calabria, Italy
| | - Carmine Zoccali
- Renal Research Institute, New York, NY, USA
- Institute of Molecular Biology and Genetics, Ariano Irpino, Italy
- Associazione Ipertensione Nefrologia Trapianto Renale, Grande Ospedale Metropolitano, c/o Nefrologia, Reggio Calabria, Italy
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Tomita-Yagi A, Ozeki-Okuno N, Watanabe-Uehara N, Komaki K, Umehara M, Sawada-Yamauchi H, Minamida A, Sunahara Y, Matoba Y, Nakamura I, Nakata T, Nakai K, Ida T, Yamashita N, Kamezaki M, Kirita Y, Taniguchi T, Konishi E, Matoba S, Tamagaki K, Kusaba T. The importance of proinflammatory failed-repair tubular epithelia as a predictor of diabetic kidney disease progression. iScience 2024; 27:109020. [PMID: 38357667 PMCID: PMC10865398 DOI: 10.1016/j.isci.2024.109020] [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: 07/27/2023] [Revised: 11/17/2023] [Accepted: 01/22/2024] [Indexed: 02/16/2024] Open
Abstract
The immense public health burden of diabetic kidney disease (DKD) has led to an increase in research on the pathophysiology of advanced DKD. The present study focused on the significance of proinflammatory vascular cell adhesion molecule 1 (VCAM1)+ tubules in DKD progression. A retrospective cohort study of DKD patients showed that the percentage of VCAM1+ tubules in kidney samples was correlated with poor renal outcomes. We established an advanced DKD model by partial resection of the kidneys of db/db mice and demonstrated that it closely resembled the human advanced DKD phenotype, with tissue hypoxia, tubular DNA damage, tissue inflammation, and high tubular VCAM1 expression. Luseogliflozin ameliorated tissue hypoxia and proinflammatory responses, including VCAM1+ expression, in tubules. These findings suggest the potential of tubular VCAM1 as a histological marker for poor DKD outcomes. SGLT2 inhibitors may attenuate tissue hypoxia and subsequent tissue inflammation in advanced DKD, thereby ameliorating tubular injury.
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Affiliation(s)
- Aya Tomita-Yagi
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Natsuko Ozeki-Okuno
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Noriko Watanabe-Uehara
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazumi Komaki
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Minato Umehara
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hiroko Sawada-Yamauchi
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Minamida
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yasuto Sunahara
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yayoi Matoba
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Itaru Nakamura
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomohiro Nakata
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kunihiro Nakai
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomoharu Ida
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Noriyuki Yamashita
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Michitsugu Kamezaki
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuhei Kirita
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takuya Taniguchi
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Eiichi Konishi
- Department of Surgical Pathology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Satoaki Matoba
- Department of Cardiovascular Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Keiichi Tamagaki
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tetsuro Kusaba
- Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Gordon WE, Baek S, Nguyen HP, Kuo YM, Bradley R, Fong SL, Kim N, Galazyuk A, Lee I, Ingala MR, Simmons NB, Schountz T, Cooper LN, Georgakopoulos-Soares I, Hemberg M, Ahituv N. Integrative single-cell characterization of a frugivorous and an insectivorous bat kidney and pancreas. Nat Commun 2024; 15:12. [PMID: 38195585 PMCID: PMC10776631 DOI: 10.1038/s41467-023-44186-y] [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: 03/13/2023] [Accepted: 12/03/2023] [Indexed: 01/11/2024] Open
Abstract
Frugivory evolved multiple times in mammals, including bats. However, the cellular and molecular components driving it remain largely unknown. Here, we use integrative single-cell sequencing (scRNA-seq and scATAC-seq) on insectivorous (Eptesicus fuscus; big brown bat) and frugivorous (Artibeus jamaicensis; Jamaican fruit bat) bat kidneys and pancreases and identify key cell population, gene expression and regulatory differences associated with the Jamaican fruit bat that also relate to human disease, particularly diabetes. We find a decrease in loop of Henle and an increase in collecting duct cells, and differentially active genes and regulatory elements involved in fluid and electrolyte balance in the Jamaican fruit bat kidney. The Jamaican fruit bat pancreas shows an increase in endocrine and a decrease in exocrine cells, and differences in genes and regulatory elements involved in insulin regulation. We also find that these frugivorous bats share several molecular characteristics with human diabetes. Combined, our work provides insights from a frugivorous mammal that could be leveraged for therapeutic purposes.
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Affiliation(s)
- Wei E Gordon
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
- Department of Biology, Menlo College, 1000 El Camino Real, Atherton, CA, 94027, USA
| | - Seungbyn Baek
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hai P Nguyen
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Yien-Ming Kuo
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Rachael Bradley
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Sarah L Fong
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Nayeon Kim
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
| | - Alex Galazyuk
- Hearing Research Focus Area, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, USA
| | - Insuk Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, 03722, Republic of Korea
- POSTECH Biotech Center, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Melissa R Ingala
- Department of Biological Sciences, Fairleigh Dickinson University, Madison, NJ, 07940, USA
| | - Nancy B Simmons
- Division of Vertebrate Zoology, Department of Mammalogy, American Museum of Natural History, New York, NY, 10024, USA
| | - Tony Schountz
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Lisa Noelle Cooper
- Musculoskeletal Research Focus Area, Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | - Ilias Georgakopoulos-Soares
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Martin Hemberg
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
| | - Nadav Ahituv
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA, 94158, USA.
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA.
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Zheng X, Yin L, Song J, Chen J, Gu W, Shi M, Zhang H. ELABELA protects against diabetic kidney disease by activating high glucose-inhibited renal tubular autophagy. J Biomed Res 2023; 37:460-469. [PMID: 38018421 PMCID: PMC10687528 DOI: 10.7555/jbr.37.20220214] [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: 09/26/2022] [Revised: 05/28/2023] [Accepted: 05/30/2023] [Indexed: 11/30/2023] Open
Abstract
ELABELA (ELA), an endogenous ligand of the apelin receptor (also known as apelin peptide jejunum [APJ]), has been shown to decrease in the plasma of patients with diabetic kidney disease (DKD). In the current study, we explored the potential function as well as the underlying mechanisms of ELA in DKD. We first found that the ELA levels were decreased in the kidneys of DKD mice. Then, we found that ELA administration mitigated renal damage and downregulated the expression of fibronectin, collagen Ⅳ, and transforming growth factor-β1 in the db/db mice and the high glucose cultured HK-2 cells. Furthermore, the autophagy markers, Beclin-1 and LC3-Ⅱ/LC3-Ⅰ ratio, were significantly impaired in DKD, but the ELA treatment reversed these alterations. Mechanistically, the inhibitory effects of ELA on the secretion of fibrosis-associated proteins in high glucose conditions were blocked by pretreatment with 3-methyladenine (an autophagy inhibitor). In summary, these in vivo and in vitro results demonstrate that ELA effectively protects against DKD by activating high glucose-inhibited renal tubular autophagy, potentially serving as a novel therapeutic candidate for DKD.
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Affiliation(s)
- Xiyin Zheng
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
| | - Lulu Yin
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
| | - Jing Song
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
| | - Juan Chen
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
| | - Wensha Gu
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
| | - Min Shi
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
| | - Hong Zhang
- Department of Endocrinology, the Affiliated Huai'an No. 1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu 223300, China
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Wang Y, Jin M, Cheng CK, Li Q. Tubular injury in diabetic kidney disease: molecular mechanisms and potential therapeutic perspectives. Front Endocrinol (Lausanne) 2023; 14:1238927. [PMID: 37600689 PMCID: PMC10433744 DOI: 10.3389/fendo.2023.1238927] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Diabetic kidney disease (DKD) is a chronic complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. Currently, there are limited therapeutic drugs available for DKD. While previous research has primarily focused on glomerular injury, recent studies have increasingly emphasized the role of renal tubular injury in the pathogenesis of DKD. Various factors, including hyperglycemia, lipid accumulation, oxidative stress, hypoxia, RAAS, ER stress, inflammation, EMT and programmed cell death, have been shown to induce renal tubular injury and contribute to the progression of DKD. Additionally, traditional hypoglycemic drugs, anti-inflammation therapies, anti-senescence therapies, mineralocorticoid receptor antagonists, and stem cell therapies have demonstrated their potential to alleviate renal tubular injury in DKD. This review will provide insights into the latest research on the mechanisms and treatments of renal tubular injury in DKD.
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Affiliation(s)
- Yu Wang
- Department of Endocrinology and Metabolism, Shenzhen University General Hospital, Shenzhen, Guangdong, China
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Mingyue Jin
- Department of Endocrinology and Metabolism, Shenzhen University General Hospital, Shenzhen, Guangdong, China
| | - Chak Kwong Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Qiang Li
- Department of Endocrinology and Metabolism, Shenzhen University General Hospital, Shenzhen, Guangdong, China
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Yu H, Wang M, Yu J, Tang H, Xu Q, Cheng N, Luo X, Wang Y, Ge H, Qiang L, Tang W, Gu HF. Evaluation of the efficacy of Abelmoschus manihot (L.) on diabetic nephropathy by analyzing biomarkers in the glomeruli and proximal and distal convoluted tubules of the kidneys. Front Pharmacol 2023; 14:1215996. [PMID: 37587982 PMCID: PMC10427220 DOI: 10.3389/fphar.2023.1215996] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 07/14/2023] [Indexed: 08/18/2023] Open
Abstract
Introduction: As a traditional Chinese medicine, Abelmoschus manihot (L.) in the form of Huangkui (HK) capsule has been used as a medication for kidney diseases, including diabetic nephropathy (DN), in China. The most significant effect of HK capsule treatment in kidney diseases is the reduction of albuminuria and proteinuria. To evaluate the efficacy of HK capsule in the regression of DN, in the current study, we analyzed the biomarkers in the glomerulus and proximal and distal convoluted tubules in the kidneys of db/db mice, the animal model for type 2 diabetes and DN. Methods: Huangkui capsules (0.84 g/kg/d) or vehicle were administered daily via oral gavage for 4 weeks in db/db mice. Urinary albumin-to-creatinine ratio and blood glucose levels were measured during the whole experimental period. Five biomarkers in the glomerulus and proximal and distal convoluted tubules in the kidneys were selected, namely, col4a3, slc5a2, slc34a1, slc12a3, and slc4a1, and their activities at mRNA and protein levels before and after HK capsule treatment were analyzed by real-time RT-PCR and immunohistochemistry. Result and discussion: After HK capsule treatment for 4 weeks, the urinary albumin-to-creatinine ratio in db/db mice was found to be significantly decreased. The activities of col4a3, slc5a2, slc34a1, slc12a3, and slc4a1 in the kidneys were upregulated in db/db mice prior to the treatment but downregulated after HK capsule treatment. Further analyses of the fields of whole kidney tissue sections demonstrated that the number of nephrons in the kidneys of db/db mice with HK capsule treatment was higher than that in the kidneys of db/db mice without HK capsule treatment. Thereby, the current study provides experimental evidence confirming the medical efficacy of A. manihot in the reduction of albuminuria and proteinuria, suggesting that A. manihot may have pharmacological efficacy in the regression of the development of type 2 diabetes-DN.
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Affiliation(s)
- Hongmei Yu
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Mei Wang
- Suzhong Pharmaceutical Research Institute, Nanjing, China
| | - Jingshi Yu
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Haitao Tang
- Suzhong Pharmaceutical Research Institute, Nanjing, China
| | - Qing Xu
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Ning Cheng
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xiaoxiao Luo
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Yurong Wang
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Haitao Ge
- Suzhong Pharmaceutical Research Institute, Nanjing, China
| | - Lei Qiang
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Wei Tang
- Department of Endocrinology, Islet Cell Senescence and Function Research Laboratory, Nanjing Medical University Affiliated Geriatric Hospital/Jiangsu Province Geriatric Hospital, Nanjing, China
| | - Harvest F. Gu
- Laboratory of Molecular Medicine, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
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Gordon WE, Baek S, Nguyen HP, Kuo YM, Bradley R, Galazyuk A, Lee I, Ingala MR, Simmons NB, Schountz T, Cooper LN, Georgakopoulos-Soares I, Hemberg M, Ahituv N. Integrative single-cell characterization of frugivory adaptations in the bat kidney and pancreas. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.12.528204. [PMID: 36824791 PMCID: PMC9949079 DOI: 10.1101/2023.02.12.528204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Frugivory evolved multiple times in mammals, including bats. However, the cellular and molecular components driving it remain largely unknown. Here, we used integrative single-cell sequencing on insectivorous and frugivorous bat kidneys and pancreases and identified key cell population, gene expression and regulatory element differences associated with frugivorous adaptation that also relate to human disease, particularly diabetes. We found an increase in collecting duct cells and differentially active genes and regulatory elements involved in fluid and electrolyte balance in the frugivore kidney. In the frugivorous pancreas, we observed an increase in endocrine and a decrease in exocrine cells and differences in genes and regulatory elements involved in insulin regulation. Combined, our work provides novel insights into frugivorous adaptation that also could be leveraged for therapeutic purposes.
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Sinha F, Federlein A, Biesold A, Schwarzfischer M, Krieger K, Schweda F, Tauber P. Empagliflozin increases kidney weight due to increased cell size in the proximal tubule S3 segment and the collecting duct. Front Pharmacol 2023; 14:1118358. [PMID: 37033639 PMCID: PMC10076569 DOI: 10.3389/fphar.2023.1118358] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/14/2023] [Indexed: 04/11/2023] Open
Abstract
The inhibition of renal SGLT2 glucose reabsorption has proven its therapeutic efficacy in chronic kidney disease. SGLT2 inhibitors (SGLTi) have been intensively studied in rodent models to identify the mechanisms of SGLT2i-mediated nephroprotection. So far, the overwhelming effects from clinical trials, could only partially be reproduced in rodent models of renal injury. However, a commonly disregarded observation from these studies, is the increase in kidney weight after SGLT2i administration. Increased kidney mass often relies on tubular growth in response to reabsorption overload during glomerular hyperfiltration. Since SGLT2i suppress hyperfiltration but concomitantly increase renal weight, it seems likely that SGLT2i have a growth promoting effect on the kidney itself, independent of GFR control. This study aimed to investigate the effect of SGLT2i on kidney growth in wildtype animals, to identify enlarged nephron segments and classify the size increase as hypertrophic/hyperplastic growth or cell swelling. SGLT2i empagliflozin increased kidney weight in wildtype mice by 13% compared to controls, while bodyweight and other organs were not affected. The enlarged nephron segments were identified as SGLT2-negative distal segments of proximal tubules and as collecting ducts by histological quantification of tubular cell area. In both segments protein/DNA ratio, a marker for hypertrophic growth, was increased by 6% and 12% respectively, while tubular nuclei number (hyperplasia) was unchanged by empagliflozin. SGLT2-inhibition in early proximal tubules induces a shift of NaCl resorption along the nephron causing compensatory NaCl and H2O reabsorption and presumably cell growth in downstream segments. Consistently, in collecting ducts of empagliflozin-treated mice, mRNA expression of the Na+-channel ENaC and the H2O-channels Aqp-2/Aqp-3 were increased. In addition, the hypoxia marker Hif1α was found increased in intercalated cells of the collecting duct together with evidence for increased proton secretion, as indicated by upregulation of carbonic anhydrases and acidified urine pH in empagliflozin-treated animals. In summary, these data show that SGLT2i induce cell enlargement by hypertrophic growth and possibly cell swelling in healthy kidneys, probably as a result of compensatory glucose, NaCl and H2O hyperreabsorption of SGLT2-negative segments. Particularly affected are the SGLT2-negative proximal tubules (S3) and the collecting duct, areas of low O2 availability.
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Liu H, Feng J, Tang L. Early renal structural changes and potential biomarkers in diabetic nephropathy. Front Physiol 2022; 13:1020443. [PMID: 36425298 PMCID: PMC9679365 DOI: 10.3389/fphys.2022.1020443] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/26/2022] [Indexed: 08/10/2023] Open
Abstract
Diabetic nephropathy is one of the most serious microvascular complications of diabetes mellitus, with increasing prevalence and mortality. Currently, renal function is assessed clinically using albumin excretion rate and glomerular filtration rate. But before the appearance of micro-albumin, the glomerular structure has been severely damaged. Glomerular filtration rate based on serum creatinine is a certain underestimate of renal status. Early diagnosis of diabetic nephropathy has an important role in improving kidney function and delaying disease progression with drugs. There is an urgent need for biomarkers that can characterize the structural changes associated with the kidney. In this review, we focus on the early glomerular and tubular structural alterations, with a detailed description of the glomerular injury markers SMAD1 and Podocalyxin, and the tubular injury markers NGAL, Netrin-1, and L-FABP in the context of diabetic nephropathy. We have summarized the currently studied protein markers and performed bioprocess analysis. Also, a brief review of proteomic and scRNA-seq method in the search of diabetic nephropathy.
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Affiliation(s)
- Hao Liu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
| | - Jianguo Feng
- Department of Anesthesiology, The Affiliated Hospital of Southwest Medical University; Laboratory of Anesthesiology, Southwest Medical University, Luzhou, China
| | - Liling Tang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, China
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Alqallaf A, Swan P, Docherty NG. Renal insulin resistance in type 2 diabetes mellitus and progression of chronic kidney disease: potential pathogenic mechanisms. Expert Rev Endocrinol Metab 2022; 17:523-532. [PMID: 36203374 DOI: 10.1080/17446651.2022.2131534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/28/2022] [Indexed: 01/06/2023]
Abstract
INTRODUCTION A bidirectional association exists between insulin resistance (IR) and chronic kidney disease (CKD) in Type 2 Diabetes Mellitus (T2DM). Baseline measures of IR are predictive of CKD progression, and uremia in progressive CKD is itself, in turn, associated with a worsening of IR. Pre-clinical research reveals that intrinsic IR in glomerular podocytes and the renal tubule may serve as a pathogenic driver of CKD in T2DM. AREAS COVERED The present manuscript takes as its point of departure, the recently identified prognostic utility of severe insulin resistance as a predictor of CKD in T2DM. Findings from a series of studies describing the association of IR with pathological alterations in both established, and less commonly assessed dynamic measures of renal impairment are discussed. Drawing upon the pre-clinical mechanistic evidence base, the cellular and molecular basis of intrinsic renal IR as a promoter of CKD is considered. EXPERT OPINION Measurement of insulin sensitivity may add value to profiling of renal risk in T2DM. Rational selection of therapeutic strategies targeting the enhancement of insulin sensitivity merits special attention regarding the personalized management of CKD in insulin resistance predominant T2DM.
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Affiliation(s)
- Alrataj Alqallaf
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland
| | - Patrick Swan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland
| | - Neil G Docherty
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine, University College Dublin, Dublin, Ireland
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Col4a3-/- Mice on Balb/C Background Have Less Severe Cardiorespiratory Phenotype and SGLT2 Over-Expression Compared to 129x1/SvJ and C57Bl/6 Backgrounds. Int J Mol Sci 2022; 23:ijms23126674. [PMID: 35743114 PMCID: PMC9223785 DOI: 10.3390/ijms23126674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/12/2022] [Accepted: 06/13/2022] [Indexed: 01/27/2023] Open
Abstract
Alport syndrome (AS) is a hereditary renal disorder with no etiological therapy. In the preclinical Col4a3-/- model of AS, disease progression and severity vary depending on mouse strain. The sodium-glucose cotransporter 2 (SGLT2) is emerging as an attractive therapeutic target in cardiac/renal pathologies, but its application to AS remains untested. This study investigates cardiorespiratory function and SGLT2 renal expression in Col4a3-/- mice from three different genetic backgrounds, 129x1/SvJ, C57Bl/6 and Balb/C. male Col4a3-/- 129x1/SvJ mice displayed alterations consistent with heart failure with preserved ejection fraction (HFpEF). Female, but not male, C57Bl/6 and Balb/C Col4a3-/- mice exhibited mild changes in systolic and diastolic function of the heart by echocardiography. Male C57Bl/6 Col4a3-/- mice presented systolic dysfunction by invasive hemodynamic analysis. All strains except Balb/C males demonstrated alterations in respiratory function. SGLT2 expression was significantly increased in AS compared to WT mice from all strains. However, cardiorespiratory abnormalities and SGLT2 over-expression were significantly less in AS Balb/C mice compared to the other two strains. Systolic blood pressure was significantly elevated only in mutant 129x1/SvJ mice. The results provide further evidence for strain-dependent cardiorespiratory and hypertensive phenotype variations in mouse AS models, corroborated by renal SGLT2 expression, and support ongoing initiatives to develop SGLT2 inhibitors for the treatment of AS.
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Yang Y, Xu G. Update on Pathogenesis of Glomerular Hyperfiltration in Early Diabetic Kidney Disease. Front Endocrinol (Lausanne) 2022; 13:872918. [PMID: 35663316 PMCID: PMC9161673 DOI: 10.3389/fendo.2022.872918] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/11/2022] [Indexed: 11/13/2022] Open
Abstract
In the existing stages of diabetic kidney disease (DKD), the first stage of DKD is called the preclinical stage, characterized by glomerular hyperfiltration, an abnormally elevated glomerular filtration rate. Glomerular hyperfiltration is an independent risk factor for accelerated deterioration of renal function and progression of nephropathy, which is associated with a high risk for metabolic and cardiovascular disease. It is imperative to understand hyperfiltration and identify potential treatments to delay DKD progress. This paper summarizes the current mechanisms of hyperfiltration in early DKD. We pay close attention to the effect of glucose reabsorption mediated by sodium-glucose cotransporters and renal growth on hyperfiltration in DKD patients, as well as the mechanisms of nitric oxide and adenosine actions on renal afferent arterioles via tubuloglomerular feedback. Furthermore, we also focus on the contribution of the atrial natriuretic peptide, cyclooxygenase, renin-angiotensin-aldosterone system, and endothelin on hyperfiltration. Proposing potential treatments based on these mechanisms may offer new therapeutic opportunities to reduce the renal burden in this population.
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