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Zhang H, Deng Z, Wang Y. Molecular insight in intrarenal inflammation affecting four main types of cells in nephrons in IgA nephropathy. Front Med (Lausanne) 2023; 10:1128393. [PMID: 36968836 PMCID: PMC10034350 DOI: 10.3389/fmed.2023.1128393] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/13/2023] [Indexed: 03/29/2023] Open
Abstract
Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis and the leading cause of kidney failure in the world. The current widely accepted framework for its pathogenesis is the "multi-hit hypothesis." In this review, we mainly discussed the intrarenal inflammation in IgAN, which is initiated by immune complex deposition with complement molecule activation, by focusing on four main types of cells in nephrons including mesangial cells, endothelial cells, podocytes, and tubular epithelial cells (TECs). Galactose-deficient IgA1 (Gd-IgA1)-containing immune complexes deposit in the mesangium and activate complement molecules and mesangial cells. Activation of mesangial cells by Gd-IgA1 deposition with enhanced cellular proliferation, extracellular matrix (ECM) expansion, and inflammatory response plays a central role in the pathogenesis of IgAN. Regional immune complex deposition and mesangial-endothelial crosstalk result in hyperpermeability of endothelium with loss of endothelial cells and infiltration barrier proteins, and recruitment of inflammatory cells. Podocyte damage is mainly derived from mesangial-podocyte crosstalk, in which tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), renin-angiotensin-aldosterone system (RAAS), and micro-RNAs are the major players in podocyte apoptosis and disorganization of slit diaphragm (SD) related to proteinuria in patients with IgAN. In addition to filtrated proteins into tubulointerstitium and mesangial-tubular crosstalk involved in the injury of TECs, retinoic acid has been discovered innovatively participating in TEC injury.
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Noncoding RNAs associated with IgA nephropathy. J Nephrol 2022; 36:911-923. [PMID: 36495425 DOI: 10.1007/s40620-022-01498-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/10/2022] [Indexed: 12/14/2022]
Abstract
IgA nephropathy (IgAN) is one of the most common glomerulonephritides. The disease is characterized by haematuria, proteinuria, deposition of galactose-deficient IgA1 in the glomerular mesangium and mesangial hypercellularity, further leading to extracellular matrix expansion. Kidney biopsy is the gold standard for IgAN diagnosis. Due to the invasiveness of renal biopsy, there is an unmet need for noninvasive biomarkers to diagnose and estimate the severity of IgAN. Understanding the role of RNA molecules as genetic markers to target diseases may allow developing therapeutic and diagnostic markers. In this review we have focused on intrarenal, extrarenal and extracellular noncoding RNAs involved in the progression of IgAN. This narrative review summarizes the pathogenesis of IgAN along with the correlation of noncoding RNA molecules such as microRNAs, small interfering RNAs, circular RNAs and long non-coding RNAs that play an important role in regulating gene expression, and that represent another type of regulation affecting the expression of specific glycosyltranferases, a key element contributing to the development of IgAN.
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Barratt J, Pawluczyk I, Selvaskandan H. Clinical application of microRNAs in glomerular diseases. Nephrol Dial Transplant 2022; 38:1375-1384. [PMID: 35906877 DOI: 10.1093/ndt/gfac230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Indexed: 11/13/2022] Open
Abstract
RNA interference (RNAi) occurs in all organisms and modulates most, if not all, biological pathways. It is the process by which non-coding RNAs, including microRNAs (miRs), regulate gene transcription and post-transcriptional processing of messenger RNA (mRNA). A single miR can modulate several genes within a cell, and several miRs can regulate expression of the same gene, adding tiers of complexity to regulation of gene expression. MicroRNAs and other RNAi approaches have been successfully used in vitro and in vivo to selectively manipulate gene transcription, making them pivotal agents for basic science research and candidates for targeted therapeutics. This review will focus on miRs and their potential as biomarkers and novel therapeutics for glomerular disease.
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Affiliation(s)
- Jonathan Barratt
- University of Leicester, Department of Cardiovascular Sciences, Leicester, UK
| | - Izabella Pawluczyk
- University of Leicester, Department of Cardiovascular Sciences, Leicester, UK
| | - Haresh Selvaskandan
- University of Leicester, Department of Cardiovascular Sciences, Leicester, UK
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Liu F, Chen J, Luo C, Meng X. Pathogenic Role of MicroRNA Dysregulation in Podocytopathies. Front Physiol 2022; 13:948094. [PMID: 35845986 PMCID: PMC9277480 DOI: 10.3389/fphys.2022.948094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
MicroRNAs (miRNAs) participate in the regulation of various important biological processes by regulating the expression of various genes at the post-transcriptional level. Podocytopathies are a series of renal diseases in which direct or indirect damage of podocytes results in proteinuria or nephrotic syndrome. Despite decades of research, the exact pathogenesis of podocytopathies remains incompletely understood and effective therapies are still lacking. An increasing body of evidence has revealed a critical role of miRNAs dysregulation in the onset and progression of podocytopathies. Moreover, several lines of research aimed at improving common podocytopathies diagnostic tools and avoiding invasive kidney biopsies have also identified circulating and urine miRNAs as possible diagnostic and prognostic biomarkers for podocytopathies. The present review mainly aims to provide an updated overview of the recent achievements in research on the potential applicability of miRNAs involved in renal disorders related to podocyte dysfunction by laying particular emphasis on focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD), membranous nephropathy (MN), diabetic kidney disease (DKD) and IgA nephropathy (IgAN). Further investigation into these dysregulated miRNAs will not only generate novel insights into the mechanisms of podocytopathies, but also might yield novel strategies for the diagnosis and therapy of this disease.
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Affiliation(s)
- Feng Liu
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiefang Chen
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Changqing Luo
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Changqing Luo, ; Xianfang Meng,
| | - Xianfang Meng
- Department of Neurobiology, Institute of Brain Research, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Changqing Luo, ; Xianfang Meng,
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Wen L, Zhao Z, Li F, Ji F, Wen J. ICAM-1 related long noncoding RNA is associated with progression of IgA nephropathy and fibrotic changes in proximal tubular cells. Sci Rep 2022; 12:9645. [PMID: 35688937 PMCID: PMC9187724 DOI: 10.1038/s41598-022-13521-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 05/25/2022] [Indexed: 11/09/2022] Open
Abstract
Intercellular adhesion molecule 1 (ICAM-1) related long noncoding RNA (ICR) is on the antisense strand of ICAM-1 and regulates ICAM-1 expression. ICAM-1 is involved in renal tubulointerstitial injury; however, the expression and clinical implication of ICR are not determined in IgA nephropathy (IgAN). We compared renal ICR levels in 337 IgAN patients with those of 89 biopsy controls, and a markedly increased ICR level was observed in IgAN patients. By Cox proportional hazards models, higher levels of renal ICR were independently associated with disease progression event defined as end-stage renal disease or ≥ 40% decline in estimated glomerular filtration rate. Patients in the highest tertile of renal ICR had a 3.5-fold higher risk for disease progression compared with those in the lowest tertile. The addition of renal ICR to a model with traditional risk factors improved risk prediction of disease progression (net reclassification index: 0.31 [95% CI 0.01–0.50]; integrated discrimination index: 0.10 [95% CI 0.04–0.16]). Inhibition of ICR by transfection with plasmids containing ICR shRNA significantly reduced expression of collagen I and α-SMA, and phosphorylation of Akt and mTOR in TGF-β1- treated HK-2 cells. Our findings suggest that renal ICR might be an independent predictor of IgAN progression and contribute to renal fibrosis.
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Affiliation(s)
- Lu Wen
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
| | - Zhanzheng Zhao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
| | - Fanghua Li
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Fengping Ji
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jianguo Wen
- Henan Joint International Pediatric Urodynamic Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
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Wen L, Wang X, Ji F, Wen J, Zhao Z. Renal Megalin mRNA Downregulation Is Associated with CKD Progression in IgA Nephropathy. Am J Nephrol 2022; 53:481-489. [PMID: 35661648 DOI: 10.1159/000524929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 04/29/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Megalin plays an important role in proximal tubule uptake of filtered proteins. Downregulation and dysfunction of megalin were previously demonstrated in IgA nephropathy (IgAN); however, its relationship to IgAN progression remains unclear. METHODS We measured renal megalin mRNA and miR-148b, previously identified as a regulator of megalin, in a retrospective cohort of 417 IgAN patients at the time of biopsy, and evaluated their associations with chronic kidney disease (CKD) progression event, defined as end-stage renal disease or ≥40% decline in estimated glomerular filtration rate, using Cox proportional hazard models. Risk classification statistics were calculated for CKD progression. RESULTS During a median follow-up of 43 months, 121 (29.0%) patients reached the CKD progression event. Patients in the highest tertile of renal megalin mRNA had a lower risk for CKD progression than in the lowest tertile (hazard ratio (HR): 0.407, 95% confidence interval (CI) 0.231-0.719; p = 0.002). Log megalin mRNA was independent and negatively associated with CKD progression in IgAN (HR: 0.529, 95% CI 0.377-0.742; p < 0.001). The addition of renal megalin mRNA to a model with traditional risk factors improved risk prediction of disease progression (C statistic from 0.76 to 0.80; integrated discrimination index: 0.04 [95% CI: 0.02-0.07]). Moreover, patients in the highest tertile of renal miR-148b had a 2.3-fold higher risk for CKD progression compared with those in the lowest tertile. CONCLUSIONS Lower renal megalin mRNA levels were associated with a greater risk of CKD progression in IgAN independent of clinical and pathological characteristics, suggesting that renal megalin could be an important prognostic factor for IgAN.
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Affiliation(s)
- Lu Wen
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiaoyang Wang
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Fengping Ji
- Department of Urology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Jianguo Wen
- Henan Joint International Pediatric Urodynamic Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhanzheng Zhao
- Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Abstract
IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. It is considered that the pathogenesis of IgAN involves the ‘multiple hit theory’ and the immune-inflammatory mechanism; however, these theories have certain limitations. The gold standard for diagnosing IgAN is still renal biopsy. Although renal biopsy is accurate, it is traumatic and is associated with some risks and limitations, so there is a need for non-invasive diagnostic methods. According to recent studies, microRNAs (miRNAs) play important roles in the occurrence and development of IgAN; thus, they provide the possibility of the noninvasive diagnosis of IgAN and also have some value in predicting prognosis. This review summarizes the current research status of miRNAs in the occurrence, development, diagnosis, and prognosis of IgAN. We also highlight some interesting and challenging points that require further study.
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Affiliation(s)
- Xingchen Yao
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,The Renal Research Institution, Zhengzhou University, Zhengzhou, China
| | - Yaling Zhai
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,The Renal Research Institution, Zhengzhou University, Zhengzhou, China
| | - Huanping An
- Medicine Experiment Center, Hanzhong Vocational and Technical College, Hanzhong, China
| | - Jingge Gao
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,The Renal Research Institution, Zhengzhou University, Zhengzhou, China
| | - Yazhuo Chen
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,The Renal Research Institution, Zhengzhou University, Zhengzhou, China
| | - Wenhui Zhang
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,The Renal Research Institution, Zhengzhou University, Zhengzhou, China
| | - Zhanzheng Zhao
- Department of Nephrology, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.,The Renal Research Institution, Zhengzhou University, Zhengzhou, China
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Yang K, Zhang Y, Mai X, Hu L, Ma C, Wei J. MIR17HG genetic variations affect the susceptibility of IgA nephropathy in Chinese Han people. Gene 2021; 800:145838. [PMID: 34274472 DOI: 10.1016/j.gene.2021.145838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/30/2021] [Accepted: 07/13/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND Immunoglobulin A nephropathy (IgAN) is the most common primary glomerular disease worldwide. It accounts for approximately 30 ~ 40% of glomerular diseases in China. However, the exact pathogenesis of IgAN is not well established. This study aimed to explore the association between MIR17HG polymorphisms and IgAN susceptibility. METHODS Six single nucleotide polymorphisms (SNPs) of MIR17HG were genotyped in 417 patients with IgAN and 424 healthy controls. The association analysis was conducted by logistic regression adjusted for age and gender in multiple genetic models and different subgroups. RESULTS Our results revealed that rs72640334 and rs1428 increased the susceptibility to IgAN in total populations (p < 0.05). The stratification analysis by age indicated that rs72640334 enhanced the risk of IgAN people older than 35 years, while rs7318578 played a protective role in the development of IgAN patients aged >35 years (p < 0.05). In addition, MIR17HG-rs72640334 could facilitate the occurrence of IgAN in females (p < 0.05). In Lee's grade III-Vsubgroup, rs72640334 and rs7336610 have an increasing effect on IgAN risk, while rs7318578 has a decreasing effect on IgAN susceptibility (p < 0.05). CONCLUSIONS Our findings suggested that MIR17HG genetic polymorphisms were correlated with IgAN susceptibility. It provided new evidence for the potential molecular mechanism of IgAN and may serve as a new biomarker for the treatment and early diagnosis of IgAN.
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Affiliation(s)
- Kai Yang
- Department of Nephrology, Hainan General Hospital, Haikou, Hainan 570311, China; Department of Nephrology, Hainan Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570311, China
| | - Ying Zhang
- Department of Nephrology, Hainan General Hospital, Haikou, Hainan 570311, China; Department of Nephrology, Hainan Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570311, China
| | - Xing Mai
- Department of Nephrology, Hainan General Hospital, Haikou, Hainan 570311, China; Department of Nephrology, Hainan Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570311, China
| | - Langtao Hu
- Department of Nephrology, Hainan General Hospital, Haikou, Hainan 570311, China; Department of Nephrology, Hainan Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570311, China
| | - Chunyang Ma
- Department of Nephrology, Hainan General Hospital, Haikou, Hainan 570311, China; Department of Nephrology, Hainan Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570311, China.
| | - Jiali Wei
- Department of Neurosurgery, First Affiliated Hospital of Hainan Medical College, Haikou, Hainan 570311, China.
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The Non-Coding RNA Landscape in IgA Nephropathy-Where Are We in 2021? J Clin Med 2021; 10:jcm10112369. [PMID: 34071162 PMCID: PMC8198207 DOI: 10.3390/jcm10112369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/19/2021] [Accepted: 05/25/2021] [Indexed: 02/07/2023] Open
Abstract
IgA nephropathy (IgAN) is the most commonly diagnosed primary glomerulonephritis worldwide. It is a slow progressing disease with approximately 30% of cases reaching end-stage kidney disease within 20 years of diagnosis. It is currently only diagnosed by an invasive biopsy and treatment options are limited. However, the current surge in interest in RNA interference is opening up new horizons for the use of this new technology in the field of IgAN management. A greater understanding of the fundamentals of RNA interference offers exciting possibilities both for biomarker discovery and, more importantly, for novel therapeutic approaches to target key pathogenic pathways in IgAN. This review aims to summarise the RNA interference literature in the context of microRNAs and their association with the multifaceted aspects of IgA nephropathy.
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Abstract
Rationale & Objective Previous studies have suggested that microRNA-21 (miR-21) plays an important role in kidney fibrosis. We examined the relationship between intrarenal miR-21 level and rate of kidney function loss in immunoglobulin A nephropathy (IgAN). Study Design Prospective cohort study. Setting & Participants 40 patients with IgAN and 10 with hypertensive nephrosclerosis as controls. Predictors miR-21 levels in kidney biopsy specimen and urinary sediment, quantified as ratio to the housekeeping gene. Outcomes Kidney event–free survival and rate of kidney function decline. Analytic Approach Time-to-event and correlation analysis. Results The IgAN group had significantly higher intrarenal miR-21 expression compared with the hypertensive nephrosclerosis group (1.71 [IQR, 0.99-2.77] vs 0.31 [IQR, 0.25-1.32]; P < 0.0001), but urinary miR-21 levels were similar. Intrarenal miR-21 expression had significant but modest correlation with severity of glomerulosclerosis (r = 0.293; P = 0.05) and tubulointerstitial fibrosis (r = 0.341; P = 0.03). Patients with high intrarenal miR-21 expression had significantly higher risk for developing kidney end points compared with those with low expression (log-rank test, P = 0.017). Univariate Cox analysis showed that intrarenal miR-21 expression significantly predicted the development of kidney end points (unadjusted HR, 1.586; 95% CI, 1.179-2.134; P = 0.002). However, the result was just short of statistical significance after adjusting for the severity of histologic damage (P = 0.06). There was also a significant correlation between intrarenal miR-21 expression and the slope of kidney function decline by univariate analysis (r = −0.399; P = 0.02). Limitations Small sample size; uncertain cellular origin of miR-21. Conclusions We found that intrarenal miR-21 expression is increased in patients with IgAN, modestly correlated with the severity of histologic damage, and predictive of subsequent kidney function loss.
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Mokhtar MM, Khidr EG, Shaban HM, Allam S, Elsadek BEM, Salama SA, Ali SS. The effect of aryl hydrocarbon receptor ligands on gentamicin-induced nephrotoxicity in rats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:16189-16202. [PMID: 32112355 DOI: 10.1007/s11356-020-08073-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 02/11/2020] [Indexed: 06/10/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs)/aryl hydrocarbon receptor (AhR) regulate the expression of target genes, including drug transporter genes which harbor xenobiotic response element (XRE) in their promoter regions. Thus, PAHs/AhR could alter the toxicokinetic profile of many nephrotoxic drugs, including aminoglycosides. In the current study, we investigated the expression and localization of AhR and megalin in rat kidney. Furthermore, we investigated whether AhR and its ligands could modulate the expression of megalin and consequently the gentamicin-induced nephrotoxicity (GN) in rats. Both megalin and AhR receptors are expressed in the proximal tubules of the rat kidney. Treatment with AhR agonist benzo(a)pyrene aggravated GN as indicated by a significant increase in serum creatinine, BUN, KIM1, NAGL, CD-86, and urinary albumin/creatinine ratio. On the other hand, treatment with AhR antagonist resveratrol ameliorated GN as manifested by a pronounced decrease in the aforementioned parameters. The effects of AhR ligands on GN were associated with altered expression of megalin receptor.
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Affiliation(s)
- Mahmoud Mohamed Mokhtar
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt.
| | - Emad Gamil Khidr
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
| | - Hesham Mohamed Shaban
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
| | - Shady Allam
- Pharmacology and Toxicology Department-Faculty of Pharmacy, Kafrelsheikh University, Kafr El Sheikh, Egypt
| | - Bakheet E M Elsadek
- Biochemistry Department-Faculty of Pharmacy (Boys), Assuit Branch, Al-Azhar University, Assuit, Egypt
| | - Salama Abdou Salama
- Pharmacology and Toxicology Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
| | - Shawkey Saddik Ali
- Biochemistry Department-Faculty of Pharmacy (Boys), Al-Azhar University, Almokhayam Aldaem Street, 6th Province, Nasr City, Cairo, 13465, Egypt
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Cabezas F, Farfán P, Marzolo MP. Participation of the SMAD2/3 signalling pathway in the down regulation of megalin/LRP2 by transforming growth factor beta (TGF-ß1). PLoS One 2019; 14:e0213127. [PMID: 31120873 PMCID: PMC6532859 DOI: 10.1371/journal.pone.0213127] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/08/2019] [Indexed: 12/19/2022] Open
Abstract
Megalin/LRP2 is a receptor that plays important roles in the physiology of several organs, such as kidney, lung, intestine, and gallbladder and also in the physiology of the nervous system. Megalin expression is reduced in diseases associated with fibrosis, including diabetic nephropathy, hepatic fibrosis and cholelithiasis, as well as in some breast and prostate cancers. One of the hallmarks of these conditions is the presence of the cytokine transforming growth factor beta (TGF-ß). Although TGF-ß has been implicated in the reduction of megalin levels, the molecular mechanism underlying this regulation is not well understood. Here, we show that treatment of two epithelial cell lines (from kidney and gallbladder) with TGF-ß1 is associated with decreased megalin mRNA and protein levels, and that these effects are reversed by inhibiting the TGF-ß1 type I receptor (TGF-ßRI). Based on in silico analyses, the two SMAD-binding elements (SBEs) in the megalin promoter are located at positions -57 and -605. Site-directed mutagenesis of the SBEs and chromatin immunoprecipitation (ChIP) experiments revealed that SMAD2/3 transcription factors interact with SBEs. Both the presence of SMAD2/3 and intact SBEs were associated with repression of the megalin promoter, in the absence as well in the presence of TGF-ß1. Also, reduced megalin expression and promoter activation triggered by high concentration of albumin are dependent on the expression of SMAD2/3. Interestingly, the histone deacetylase inhibitor Trichostatin A (TSA), which induces megalin expression, reduced the effects of TGF-ß1 on megalin mRNA levels. These data show the significance of TGF-ß and the SMAD2/3 signalling pathway in the regulation of megalin and explain the decreased megalin levels observed under conditions in which TGF-ß is upregulated, including fibrosis-associated diseases and cancer.
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Affiliation(s)
- Felipe Cabezas
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pamela Farfán
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María-Paz Marzolo
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
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