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Cybulsky AV, Papillon J, Guillemette J, Navarro-Betancourt JR, Chung CF, Iwawaki T, Fantus IG. Deletion of IRE1α in podocytes exacerbates diabetic nephropathy in mice. Sci Rep 2024; 14:11718. [PMID: 38778209 PMCID: PMC11111796 DOI: 10.1038/s41598-024-62599-7] [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: 02/19/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024] Open
Abstract
Protein misfolding in the endoplasmic reticulum (ER) of podocytes contributes to the pathogenesis of glomerular diseases. Protein misfolding activates the unfolded protein response (UPR), a compensatory signaling network. We address the role of the UPR and the UPR transducer, inositol-requiring enzyme 1α (IRE1α), in streptozotocin-induced diabetic nephropathy in mice. Diabetes caused progressive albuminuria in control mice that was exacerbated in podocyte-specific IRE1α knockout (KO) mice. Compared to diabetic controls, diabetic IRE1α KO mice showed reductions in podocyte number and synaptopodin. Glomerular ultrastructure was altered only in diabetic IRE1α KO mice; the major changes included widening of podocyte foot processes and glomerular basement membrane. Activation of the UPR and autophagy was evident in diabetic control, but not diabetic IRE1α KO mice. Analysis of human glomerular gene expression in the JuCKD-Glom database demonstrated induction of genes associated with the ER, UPR and autophagy in diabetic nephropathy. Thus, mice with podocyte-specific deletion of IRE1α demonstrate more severe diabetic nephropathy and attenuation of the glomerular UPR and autophagy, implying a protective effect of IRE1α. These results are consistent with data in human diabetic nephropathy and highlight the potential for therapeutically targeting these pathways.
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Affiliation(s)
- Andrey V Cybulsky
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, QC, Canada.
| | - Joan Papillon
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, QC, Canada
| | - Julie Guillemette
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, QC, Canada
| | - José R Navarro-Betancourt
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, QC, Canada
| | - Chen-Fang Chung
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, QC, Canada
| | - Takao Iwawaki
- Department of Life Science, Kanazawa Medical University, Uchinada, Japan
| | - I George Fantus
- Department of Medicine, McGill University Health Centre Research Institute, McGill University, Montreal, QC, Canada
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Cybulsky AV, Papillon J, Bryan C, Navarro‐Betancourt JR, Sabourin LA. Role of the Ste20-like kinase SLK in podocyte adhesion. Physiol Rep 2024; 12:e15897. [PMID: 38163671 PMCID: PMC10758337 DOI: 10.14814/phy2.15897] [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: 10/13/2023] [Revised: 11/16/2023] [Accepted: 11/16/2023] [Indexed: 01/03/2024] Open
Abstract
SLK controls the cytoskeleton, cell adhesion, and migration. Podocyte-specific deletion of SLK in mice leads to podocyte injury as mice age and exacerbates injury in experimental focal segment glomerulosclerosis (FSGS; adriamycin nephrosis). We hypothesized that adhesion proteins may be substrates of SLK. In adriamycin nephrosis, podocyte ultrastructural injury was exaggerated by SLK deletion. Analysis of a protein kinase phosphorylation site dataset showed that podocyte adhesion proteins-paxillin, vinculin, and talin-1 may be potential SLK substrates. In cultured podocytes, deletion of SLK increased adhesion to collagen. Analysis of paxillin, vinculin, and talin-1 showed that SLK deletion reduced focal adhesion complexes (FACs) containing these proteins mainly in adriamycin-induced injury; there was no change in FAC turnover (focal adhesion kinase Y397 phosphorylation). In podocytes, paxillin S250 showed basal phosphorylation that was slightly enhanced by SLK; however, SLK did not phosphorylate talin-1. In adriamycin nephrosis, SLK deletion did not alter glomerular expression/localization of talin-1 and vinculin, but increased focal adhesion kinase phosphorylation modestly. Therefore, SLK decreases podocyte adhesion, but FAC proteins in podocytes are not major substrates of SLK in health and disease.
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Affiliation(s)
- Andrey V. Cybulsky
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - Joan Papillon
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - Craig Bryan
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - José R. Navarro‐Betancourt
- Department of MedicineMcGill University Health Centre Research Institute, McGill UniversityMontrealQuebecCanada
| | - Luc A. Sabourin
- Ottawa Hospital Research Institute, Cancer TherapeuticsOttawaOntarioCanada
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Tseng CH, Shah KM, Chiu IJ, Hsiao LL. The Role of Autophagy in Type 2 Diabetic Kidney Disease Management. Cells 2023; 12:2691. [PMID: 38067119 PMCID: PMC10705810 DOI: 10.3390/cells12232691] [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: 10/12/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Diabetic kidney disease (DKD), or diabetic nephropathy (DN), is one of the most prevalent complications of type 2 diabetes mellitus (T2DM) and causes severe burden on the general welfare of T2DM patients around the world. While several new agents have shown promise in treating this condition and potentially halting the progression of the disease, more work is needed to understand the complex regulatory network involved in the disorder. Recent studies have provided new insights into the connection between autophagy, a physiological metabolic process known to maintain cellular homeostasis, and the pathophysiological pathways of DKD. Typically, autophagic activity plays a role in DKD progression mainly by promoting an inflammatory response to tissue damage, while both overactivated and downregulated autophagy worsen disease outcomes in different stages of DKD. This correlation demonstrates the potential of autophagy as a novel therapeutic target for the disease, and also highlights new possibilities for utilizing already available DN-related medications. In this review, we summarize findings on the relationship between autophagy and DKD, and the impact of these results on clinical management strategies.
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Affiliation(s)
- Che-Hao Tseng
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (C.-H.T.); (K.M.S.)
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Kavya M. Shah
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (C.-H.T.); (K.M.S.)
| | - I-Jen Chiu
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (C.-H.T.); (K.M.S.)
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
- TMU-Research Center of Urology and Kidney (TMU-RCUK), Taipei Medical University, Taipei 11031, Taiwan
| | - Li-Li Hsiao
- Renal Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA; (C.-H.T.); (K.M.S.)
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