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Ravi R, Nagarajan H, Muralikumar S, Vetrivel U, Subramaniam Rajesh B. Unveiling the therapeutic potential of a mutated paraoxonase 2 in diabetic retinopathy: Defying glycation, mitigating oxidative stress, ER stress and inflammation. Int J Biol Macromol 2024; 258:128899. [PMID: 38141706 DOI: 10.1016/j.ijbiomac.2023.128899] [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: 06/21/2023] [Revised: 11/20/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
Paraoxonase 2 (PON2) is an intracellular anti-oxidant protein ubiquitously expressed in all cells and reduces reactive oxygen species, endoplasmic reticulum (ER) stress, further improves mitochondrial function and thereby shows anti-apoptotic function. In diabetes and its complications this PON gets glycated and becomes in effective. The PON activity is reported to be reduced in diabetic retinopathy and we have earlier showed Carboxy methyl lysine (AGE) decreased PON2 expression and activity in Human retinal endothelial cells (HREC) . In this study, we have designed and developed a mutated PON2 by in silico and in vitro approach which can resist glycation. Where in glycation-prone residues in PON2 was predicted using in silico analyses and a mutated PON2 was developed using in vitro site directed mutagenesis (SDM) assay mPON2 (mutant PON2-PON2-K70A) and its efficacy was compared with wPON2 (wild type PON2). CML glycated wPON2 and reduced its activity when compared with mPON2 in HREC confirmed by immunoprecipitation and in vitro experiments. Additionally, mPON2 interaction efficiency with its substrates was higher than wPON2 by insilico assay and demonstrated enhanced inhibition against CML-induced oxidative stress, ER stress, pro-inflammation, and mitochondrial fission than wPON2 by invitro assay. Further mPON2 showed increased inhibition of phosphorylation of NFĸB induced by CML. Our investigation establishes that the over expression of mPON2 in HREC can defy glycation and therefore mitigate ER stress and inflammation against CML than endogenous wPON2. These findings imply that mPON2 can be a beneficial therapeutic target against diabetic retinopathy.
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Affiliation(s)
- Ramya Ravi
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai 600006, India; School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, India
| | - Hemavathy Nagarajan
- Centre for Bioinformatics, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai 600006, India
| | - Shalini Muralikumar
- Centre for Bioinformatics, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai 600006, India
| | - Umashankar Vetrivel
- Centre for Bioinformatics, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai 600006, India; Department of Bioinformatics, ICMR-National Institute of Traditional Medicine, Nehru Nagar, Belagavi, Karnataka 590 010, India
| | - Bharathidevi Subramaniam Rajesh
- R.S. Mehta Jain Department of Biochemistry and Cell Biology, KBIRVO, Vision Research Foundation, Sankara Nethralaya, Chennai 600006, India.
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Mutchler SM, Whelan SCM, Marciszyn A, Chen J, Kleyman TR, Shi S. Role of paraoxonase 3 in regulating ENaC-mediated Na + transport in the distal nephron. J Physiol 2024; 602:737-757. [PMID: 38345534 PMCID: PMC10940207 DOI: 10.1113/jp285034] [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: 05/16/2023] [Accepted: 01/11/2024] [Indexed: 02/18/2024] Open
Abstract
Paraoxonase 3 (PON3) is expressed in the aldosterone-sensitive distal nephron, where filtered Na+ is reabsorbed mainly via the epithelial Na+ channel (ENaC) and Na+ -coupled co-transporters. We previously showed that PON3 negatively regulates ENaC through a chaperone mechanism. The present study aimed to determine the physiological role of PON3 in renal Na+ and K+ homeostasis. Pon3 knockout (KO) mice had higher amiloride-induced natriuresis and lower plasma [K+ ] at baseline. Single channel recordings in split-open tubules showed that the number of active channels per patch was significantly higher in KO mice, resulting in a higher channel activity in the absence of PON3. Although whole kidney abundance of ENaC subunits was not altered in Pon3 KOs, ENaC gamma subunit was more apically distributed within the connecting tubules and cortical collecting ducts of Pon3 KO kidneys. Additionally, small interfering RNA-mediated knockdown of PON3 in cultured mouse cortical collecting duct cells led to an increased surface abundance of ENaC gamma subunit. As a result of lower plasma [K+ ], sodium chloride co-transporter phosphorylation was enhanced in the KO kidneys, a phenotype that was corrected by a high K+ diet. Finally, PON3 expression was upregulated in mouse kidneys under dietary K+ restriction, potentially providing a mechanism to dampen ENaC activity and associated K+ secretion. Taken together, our results show that PON3 has a role in renal Na+ and K+ homeostasis through regulating ENaC functional expression in the distal nephron. KEY POINTS: Paraoxonase 3 (PON3) is expressed in the distal nephron of mouse kidneys and functions as a molecular chaperone to reduce epithelial Na+ channel (ENaC) expression and activity in heterologous expression systems. We examined the physiological role of PON3 in renal Na+ and K+ handling using a Pon3 knockout (KO) mouse model. At baseline, Pon3 KO mice had lower blood [K+ ], more functional ENaC in connecting tubules/cortical collecting ducts, higher amiloride-induced natriuresis, and enhanced sodium chloride co-transporter (NCC) phosphorylation. Upon challenge with a high K+ diet, Pon3 KO mice had normalized blood [K+ ] and -NCC phosphorylation but lower circulating aldosterone levels compared to their littermate controls. Kidney PON3 abundance was altered in mice under dietary K+ loading or K+ restriction, providing a potential mechanism for regulating ENaC functional expression and renal Na+ and K+ homeostasis in the distal nephron.
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Affiliation(s)
| | | | - Allison Marciszyn
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jingxin Chen
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Thomas R. Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shujie Shi
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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Chen Q, Xie C, Tang K, Luo M, Zhang Z, Jin Y, Liu Y, Zhou L, Kong Y. The E3 ligase Trim63 promotes podocyte injury and proteinuria by targeting PPARα to inhibit fatty acid oxidation. Free Radic Biol Med 2023; 209:40-54. [PMID: 37793501 DOI: 10.1016/j.freeradbiomed.2023.09.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 09/21/2023] [Accepted: 09/30/2023] [Indexed: 10/06/2023]
Abstract
Podocyte injury is a hallmark of glomerular disease and one of the leading causes of chronic kidney disease (CKD). Peroxisome proliferator-activated receptor α (PPARα) plays a key role in podocyte fatty acid oxidation (FAO). However, the underlying regulatory mechanisms remain unresolved. Trim63 is an E3 ubiquitin ligase that has been shown to inhibit PPARα activity; however, its role in fatty acid metabolism in the kidney has not been elucidated to date. In this study, we investigated the effects of overexpression and knockdown of Trim63 in Adriamycin (ADR)-induced nephropathy and diabetic nephropathy models and a podocyte cell line. In both rodents and human patients with proteinuric CKD, Trim63 was upregulated, particularly in the podocytes of injured glomeruli. In the ADR-induced nephropathy model, ectopic Trim63 application aggravated FAO deficiency and mitochondrial dysfunction and triggered intense lipid deposition, podocyte injury, and proteinuria. Notably, Trim63 inhibition alleviated FAO deficiency and mitochondrial dysfunction, and markedly restored podocyte injury and renal fibrosis in ADR-induced and diabetic nephropathy (DN) models. Additionally, Trim63 was observed to mediate PPARα ubiquitination and degradation, leading to podocyte injury. We demonstrate the pathological role of Trim63, which was previously unrecognized in kidney tissue, in FAO deficiency and podocyte injury. Targeting Trim63 may represent a viable therapeutic strategy for podocyte injury and proteinuria.
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Affiliation(s)
- Qiyan Chen
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Division of Nephrology, The First People's Hospital of Foshan, Foshan, China
| | - Chao Xie
- Division of Nephrology, The First People's Hospital of Foshan, Foshan, China
| | - Kaiyue Tang
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Mujin Luo
- Division of Nephrology, The First People's Hospital of Foshan, Foshan, China
| | - Zhe Zhang
- Division of Nephrology, The First People's Hospital of Foshan, Foshan, China
| | - Yabin Jin
- Clinical Research Institute, The First People's Hospital of Foshan, Foshan, China
| | - Youhua Liu
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Lili Zhou
- State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangdong Provincial Institute of Nephrology, and Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
| | - Yaozhong Kong
- Division of Nephrology, The First People's Hospital of Foshan, Foshan, China.
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Hagmann H, Khayyat NH, Matin M, Oezel C, Chen H, Schauss A, Schell C, Benzing T, Dryer S, Brinkkoetter PT. Capsazepine (CPZ) Inhibits TRPC6 Conductance and Is Protective in Adriamycin-Induced Nephropathy and Diabetic Glomerulopathy. Cells 2023; 12:cells12020271. [PMID: 36672207 PMCID: PMC9856956 DOI: 10.3390/cells12020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/15/2022] [Accepted: 01/05/2023] [Indexed: 01/12/2023] Open
Abstract
Reactive oxygen species (ROS), which excessively arise in diabetes and systemic inflammatory diseases, modify cellular lipids and cellular lipid composition leading to altered biophysical properties of cellular membranes. The impact of lipid peroxidation on transmembrane signaling routes is not yet well studied. The canonical transient receptor potential channel 6 (TRPC6) is implicated in the pathogenesis of several forms of glomerular diseases. TRPC6 is sensitive to membrane stretch and relies on a distinct lipid environment. This study investigates the effect of oxidative alterations to plasma membrane lipids on TRPC6 activity and the function of the glomerular filter. Knockout of the anti-oxidative, lipid modifying enzyme paraoxonase 2 (PON2) leads to altered biophysical properties of glomerular epithelial cells, which are called podocytes. Cortical stiffness, quantified by atomic force microscopy, was largely increased in PON2-deficient cultured podocytes. PON2 deficiency markedly enhanced TRPC6 channel currents and channel recovery. Treatment with the amphiphilic substance capsazepine in micromolar doses reduced cortical stiffness and abrogated TRPC6 conductance. In in vivo studies, capsazepine reduced the glomerular phenotype in the model of adriamycin-induced nephropathy in PON2 knockout mice and wildtype littermates. In diabetic AKITA mice, the progression of albuminuria and diabetic kidney disease was delayed. In summary, we provide evidence that the modification of membrane characteristics affects TRPC6 signaling. These results could spur future research to investigate modification of the direct lipid environment of TRPC6 as a future therapeutic strategy in glomerular disease.
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Affiliation(s)
- Henning Hagmann
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
- Correspondence:
| | | | - Mahsa Matin
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
| | - Cem Oezel
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
| | - He Chen
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
| | - Astrid Schauss
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), 50931 Cologne, Germany
| | - Christoph Schell
- Institute of Surgical Pathology, Faculty of Medicine, University Medical Center Freiburg, 79106 Freiburg, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
- Cologne Cluster of Excellence on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), 50931 Cologne, Germany
- Systems Biology of Ageing Cologne (Sybacol), 50931 Cologne, Germany
| | - Stuart Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
- Department of Biomedical Sciences, Tilman J. Fertitta Family College of Medicine, University of Houston, Houston, TX 77204, USA
| | - Paul T. Brinkkoetter
- Department II of Internal Medicine, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Center for Molecular Medicine Cologne, University Hospital Cologne, Faculty of Medicine, University of Cologne, 50931 Cologne, Germany
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