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Claudio P, Gabriella M. Nephrotic syndrome: pathophysiology and consequences. J Nephrol 2023; 36:2179-2190. [PMID: 37466816 DOI: 10.1007/s40620-023-01697-7] [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: 03/28/2023] [Accepted: 05/30/2023] [Indexed: 07/20/2023]
Abstract
In patients with kidney disease, nephrotic syndrome can lead to several complications including progressive kidney dysfunction. Proteinuria may lead to the formation of cellular or fibrous crescents with reciprocal development of rapidly progressive glomerulonephritis or focal glomerulosclerosis. Proteinuria may also cause overload and dysfunction of tubular epithelial cells, eventually resulting in tubular atrophy and interstitial fibrosis. Hypoalbuminemia is usually associated with increased risk of mortality and kidney dysfunction. Dyslipidemia may increase the risk of atherosclerotic complications, cause podocyte dysfunction and contribute to vascular thrombosis. Urinary loss of anticoagulants and overproduction of coagulation factors may facilitate a hypercoagulable state. Edema, hypogammaglobulinemia, loss of complement factors, and immunosuppressive therapy can favor infection. Treatment of these complications may reduce their impact on the severity of NS. Nephrotic syndrome is a kidney disorder that can worsen the quality of life and increase the risk of kidney disease progression.
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Affiliation(s)
| | - Moroni Gabriella
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20072, Pieve Emanuele, Milan, Italy
- Nephrology and Dialysis Division, IRCCS Humanitas Research Hospital, Via Manzoni 56, 20089, Rozzano, Milan, Italy
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Qu L, Jiao B. The Interplay between Immune and Metabolic Pathways in Kidney Disease. Cells 2023; 12:1584. [PMID: 37371054 DOI: 10.3390/cells12121584] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Kidney disease is a significant health problem worldwide, affecting an estimated 10% of the global population. Kidney disease encompasses a diverse group of disorders that vary in their underlying pathophysiology, clinical presentation, and outcomes. These disorders include acute kidney injury (AKI), chronic kidney disease (CKD), glomerulonephritis, nephrotic syndrome, polycystic kidney disease, diabetic kidney disease, and many others. Despite their distinct etiologies, these disorders share a common feature of immune system dysregulation and metabolic disturbances. The immune system and metabolic pathways are intimately connected and interact to modulate the pathogenesis of kidney diseases. The dysregulation of immune responses in kidney diseases includes a complex interplay between various immune cell types, including resident and infiltrating immune cells, cytokines, chemokines, and complement factors. These immune factors can trigger and perpetuate kidney inflammation, causing renal tissue injury and progressive fibrosis. In addition, metabolic pathways play critical roles in the pathogenesis of kidney diseases, including glucose and lipid metabolism, oxidative stress, mitochondrial dysfunction, and altered nutrient sensing. Dysregulation of these metabolic pathways contributes to the progression of kidney disease by inducing renal tubular injury, apoptosis, and fibrosis. Recent studies have provided insights into the intricate interplay between immune and metabolic pathways in kidney diseases, revealing novel therapeutic targets for the prevention and treatment of kidney diseases. Potential therapeutic strategies include modulating immune responses through targeting key immune factors or inhibiting pro-inflammatory signaling pathways, improving mitochondrial function, and targeting nutrient-sensing pathways, such as mTOR, AMPK, and SIRT1. This review highlights the importance of the interplay between immune and metabolic pathways in kidney diseases and the potential therapeutic implications of targeting these pathways.
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Affiliation(s)
- Lili Qu
- Division of Nephrology, Department of Medicine, School of Medicine, University of Connecticut Health Center, Farmington, CT 06030-1405, USA
| | - Baihai Jiao
- Department of Immunology, School of Medicine, University of Connecticut Health Center, Farmington, CT 06030-1405, USA
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Liu L, Ning X, Wei L, Zhou Y, Zhao L, Ma F, Bai M, Yang X, Wang D, Sun S. Twist1 downregulation of PGC-1α decreases fatty acid oxidation in tubular epithelial cells, leading to kidney fibrosis. Theranostics 2022; 12:3758-3775. [PMID: 35664054 PMCID: PMC9131259 DOI: 10.7150/thno.71722] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 04/18/2022] [Indexed: 11/05/2022] Open
Abstract
Rationale: A deficiency of fatty acid oxidation (FAO) is the metabolic hallmark in proximal tubular cells (PTCs) in renal fibrosis owing to utilization of fatty acids by PTCs as the main energy source. Lipid accumulation may promote lipotoxicity-induced pathological injury in renal tissue. However, the molecular mechanism underlying lipotoxicity and renal tubulointerstitial fibrosis (TIF) remains unclear. Twist1 has been identified to play an essential role in fatty acid metabolism. We hypothesized that Twist1 may regulate FAO in PTCs and consequently facilitate lipotoxicity-induced TIF. Methods: We used hypoxia-induced Twist1 overexpression to incite defective mitochondrial FAO in PTCs, and used renal ischemia-reperfusion or unilateral ureteral obstruction to induce renal injury in mice. We used knockout cells, mice of Twist1, and Harmine to determine the role of Twist1 in FAO and TIF. Results: Overexpression of Twist1 downregulates the transcription of PGC-1α and further inhibits the expression of FAO-associated genes, such as PPARα, CPT1 and ACOX1. Consequently, reduced FAO and increased intracellular lipid droplet accumulation in a human PTC line (HK-2), leads to mitochondrial dysfunction, and production of increased profibrogenic factors. Twist1 knockout mice with renal injury had increased expression of PGC-1α, which restored FAO and obstructed progression of TIF. Strikingly, pharmacological inhibition of Twist1 by using Harmine reduced lipid accumulation and restored FAO in vitro and in vivo. Conclusion: Our findings suggest that Twist1-mediated inhibition of FAO in PTCs results in TIF and suggest that Twist1-targeted inhibition could provide a potential strategy for the treatment of renal fibrosis.
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Affiliation(s)
- Limin Liu
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China.,School of Medicine, Northwest University, 229 Taibai North Road, Xi'an, Shaanxi, 710069, China
| | - Xiaoxuan Ning
- Department of Geriatrics, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Lei Wei
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Ying Zhou
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Lijuan Zhao
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Feng Ma
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Ming Bai
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Xiaoxia Yang
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Di Wang
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
| | - Shiren Sun
- Department of Nephrology, Xijing Hospital, Fourth Military Medical University, No. 127 Chang le West Road, Xi'an, Shaanxi, 710032, China
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Sun Y, Cui S, Hou Y, Yi F. The Updates of Podocyte Lipid Metabolism in Proteinuric Kidney Disease. KIDNEY DISEASES (BASEL, SWITZERLAND) 2021; 7:438-451. [PMID: 34901191 DOI: 10.1159/000518132] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/24/2021] [Indexed: 12/23/2022]
Abstract
BACKGROUND Podocytes, functionally specialized and terminally differentiated glomerular visceral epithelial cells, are critical for maintaining the structure and function of the glomerular filtration barrier. Podocyte injury is considered as the most important early event contributing to proteinuric kidney diseases such as obesity-related renal disease, diabetic kidney disease, focal segmental glomerulosclerosis, membranous nephropathy, and minimal change disease. Although considerable advances have been made in the understanding of mechanisms that trigger podocyte injury, cell-specific and effective treatments are not clinically available. SUMMARY Emerging evidence has indicated that the disorder of podocyte lipid metabolism is closely associated with various proteinuric kidney diseases. Excessive lipid accumulation in podocytes leads to cellular dysfunction which is defined as lipotoxicity, a phenomenon characterized by mitochondrial oxidative stress, actin cytoskeleton remodeling, insulin resistance, and inflammatory response that can eventually result in podocyte hypertrophy, detachment, and death. In this review, we summarize recent advances in the understanding of lipids in podocyte biological function and the regulatory mechanisms leading to podocyte lipid accumulation in proteinuric kidney disease. KEY MESSAGES Targeting podocyte lipid metabolism may represent a novel therapeutic strategy for patients with proteinuric kidney disease.
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Affiliation(s)
- Yu Sun
- The Key Laboratory of Infection and Immunity of Shandong Province, Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Sijia Cui
- The Key Laboratory of Infection and Immunity of Shandong Province, Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Yunfeng Hou
- Intensive Care Unit, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, China
| | - Fan Yi
- The Key Laboratory of Infection and Immunity of Shandong Province, Department of Pharmacology, School of Basic Medical Sciences, Shandong University, Jinan, China
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Xue L, Zhang Y, Xu J, Lu W, Wang Q, Fu J, Liu Z. Anti-TWEAK Antibody Alleviates Renal Interstitial Fibrosis by Increasing PGC-1α Expression in Lupus Nephritis. J Inflamm Res 2021; 14:1173-1184. [PMID: 33814923 PMCID: PMC8009537 DOI: 10.2147/jir.s301356] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 03/11/2021] [Indexed: 12/26/2022] Open
Abstract
Purpose Current studies on the mechanism of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) in lupus nephritis (LN) mainly focus on the inflammatory pathway. Herein, we aimed to determine whether TWEAK could promote the progression of renal interstitial fibrosis by regulating peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) expression and intervening in lipid metabolism in LN. Materials and Methods MRL/lpr mice, an animal model of lupus, were treated with the anti-TWEAK antibody or co-treated with adeno-associated virus-mediated PGC-1α short hairpin RNA (shRNA). In addition, human proximal tubular epithelial cells (HK2 cells) were treated with recombinant human TWEAK (rhTWEAK) or ammonium pyrrolidine dithiocarbamate (PDTC) in vitro. Results The renal contents of free fatty acids and triglycerides were higher in MRL/lpr mice than in MRL/MpJ mice; however, these contents were decreased by treatment with the anti-TWEAK antibody. Based on immunofluorescence staining, the expression of PGC-1α was markedly more in the renal tubules of MRL/MpJ mice than in the glomeruli. However, treatment with anti-TWEAK antibody increased the levels of PGC-1α and its downstream target genes, which were remarkably lower in MRL/lpr mice than in MRL/MpJ mice. Anti-TWEAK antibody effectively eased renal interstitial fibrosis, which manifested as a decrease in the deposition of collagen fibers and the inhibition of type I collagen and fibronectin expression. However, the therapeutic effects of the anti-TWEAK antibody were abolished by PGC-1α shRNA. Treatment with rhTWEAK decreased PGC-1α expression in both dose- and time-dependent manners in HK2 cells in vitro. PDTC, an inhibitor of IκBα phosphorylation, suppressed the decrease in the PGC-1α protein level induced by rhTWEAK treatment. Conclusion Our results suggest that TWEAK prevents renal tubular PGC-1α expression by promoting NF-κB activation, resulting in a deficiency in lipid metabolism and the progress of renal interstitial fibrosis. The upregulation of renal tubular PGC-1α expression to improve lipid metabolism is one of the mechanisms employed by the anti-TWEAK antibody to treat renal interstitial fibrosis.
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Affiliation(s)
- Leixi Xue
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Yi Zhang
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Jiajun Xu
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Wentian Lu
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Qing Wang
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Jinxiang Fu
- Department of Hematology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Zhichun Liu
- Department of Rheumatology and Immunology, The Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
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