The cardiotonic steroid hormone marinobufagenin induces renal fibrosis: implication of epithelial-to-mesenchymal transition

We recently demonstrated that the cardiotonic steroid marinobufagenin (MBG) induced fibrosis in rat hearts through direct stimulation of collagen I secretion by cardiac fibroblasts. This stimulation was also responsible for the cardiac fibrosis seen in experimental renal failure. In this study, the effect of MBG on the development of renal fibrosis in rats was investigated. Four weeks of MBG infusion triggered mild periglomerular and peritubular fibrosis in the cortex and the appearance of fibrotic scars in the corticomedullary junction of the kidney. MBG also significantly increased the protein levels and nuclear localization of the transcription factor Snail in the tubular epithelia. It is known that activation of Snail is associated with epithelial-to-mesenchymal transition (EMT) during renal fibrosis. To examine whether MBG alone can trigger EMT, we used the porcine proximal tubular cell line LLC-PK1. MBG (100 nM) caused LLC-PK1 cells grown to confluence to acquire a fibroblast-like shape and have an invasive motility. The expressions of the mesenchymal proteins collagen I, fibronectin, and vimentin were increased twofold. However, the total level of E-cadherin remained unchanged. These alterations in LLC-PK1 cells in the presence of MBG were accompanied by elevated expression and nuclear translocation of Snail. During the time course of EMT, MBG did not have measurable inhibitory effects on the ion pumping activity of its natural ligand, Na+-K+-ATPase. Our data suggest that the MBG may be an important factor in inducing EMT and, through this mechanism, elevated levels of MBG in chronic renal failure may play a role in the progressive fibrosis.

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Inhibition of Lysine 63 Ubiquitination Prevents the Progression of Renal Fibrosis in Diabetic DBA/2J Mice

International Journal of Molecular Sciences ◽

10.3390/ijms22105194 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5194

Author(s):

Paola Pontrelli ◽

Francesca Conserva ◽

Rossella Menghini ◽

Michele Rossini ◽

Alessandra Stasi ◽

...

Keyword(s):

Diabetic Nephropathy ◽

Epithelial To Mesenchymal Transition ◽

Selective Inhibition ◽

Collagen I ◽

Protein Accumulation ◽

Mesenchymal Transition ◽

Collagen Iii ◽

Proximal Tubular Epithelial Cells

Diabetic nephropathy (DN) is the most frequent cause of end-stage renal disease. Tubulointerstitial accumulation of lysine 63 (K63)-ubiquitinated (Ub) proteins is involved in the progression of DN fibrosis and correlates with urinary miR-27b-3p downregulation. We explored the renoprotective effect of an inhibitor of K63-Ub (NSC697923), alone or in combination with the ACE-inhibitor ramipril, in vitro and in vivo. Proximal tubular epithelial cells and diabetic DBA/2J mice were treated with NSC697923 and/or ramipril. K63-Ub protein accumulation along with α-SMA, collagen I and III, FSP-1, vimentin, p16INK4A expression, SA-α Gal staining, Sirius Red, and PAS staining were measured. Finally, we measured the urinary albumin to creatinine ratio (uACR), and urinary miR-27b-3p expression in mice. NSC697923, both alone and in association with ramipril, in vitro and in vivo inhibited hyperglycemia-induced epithelial to mesenchymal transition by significantly reducing K63-Ub proteins, α-SMA, collagen I, vimentin, FSP-1 expression, and collagen III along with tubulointerstitial and glomerular fibrosis. Treated mice also showed recovery of urinary miR-27b-3p and restored expression of p16INK4A. Moreover, NSC697923 in combination with ramipril demonstrated a trend in the reduction of uACR. In conclusion, we suggest that selective inhibition of K63-Ub, when combined with the conventional treatment with ACE inhibitors, might represent a novel treatment strategy to prevent the progression of fibrosis and proteinuria in diabetic nephropathy and we propose miR-27b-3p as a biomarker of treatment efficacy.

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Fibroblast Growth Factor 21 Attenuates Diabetes-Induced Renal Fibrosis by Negatively Regulating TGF-β-p53-Smad2/3-Mediated Epithelial-to-Mesenchymal Transition via Activation of AKT

Diabetes & Metabolism Journal ◽

10.4093/dmj.2018.0235 ◽

2020 ◽

Vol 44 (1) ◽

pp. 158 ◽

Cited By ~ 2

Author(s):

Sundong Lin ◽

Lechu Yu ◽

Yongqing Ni ◽

Lulu He ◽

Xiaolu Weng ◽

...

Keyword(s):

Growth Factor ◽

Fibroblast Growth Factor ◽

Renal Fibrosis ◽

Epithelial To Mesenchymal Transition ◽

Fibroblast Growth Factor 21 ◽

Fibroblast Growth ◽

Mesenchymal Transition

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MKP2 inhibits TGF-β1-induced epithelial-to-mesenchymal transition in renal tubular epithelial cells through a JNK-dependent pathway

Clinical Science ◽

10.1042/cs20180602 ◽

2018 ◽

Vol 132 (21) ◽

pp. 2339-2355 ◽

Cited By ~ 6

Author(s):

Zhenzhen Li ◽

Xianghua Liu ◽

Fengyan Tian ◽

Ji Li ◽

Qingwei Wang ◽

...

Keyword(s):

Renal Fibrosis ◽

Epithelial To Mesenchymal Transition ◽

Transforming Growth Factor ◽

Transforming Growth Factor Β1 ◽

Mitogen Activated Protein Kinase ◽

Jnk Signaling ◽

Mesenchymal Transition ◽

Amino Terminal ◽

Ureter Obstruction ◽

Tgf Β1

Epithelial-to-mesenchymal transition (EMT) is a phenotypic conversion that plays a crucial role in renal fibrosis leading to chronic renal failure. Mitogen-activated protein kinase phosphatase 2 (MKP2) is a member of the dual-specificity MKPs that regulate the MAP kinase pathway involved in transforming growth factor-β1 (TGF-β1)-induced EMT. However, the function of MKP2 in the regulation of EMT and the underlying mechanisms are still largely unknown. In the present study, we detected the expression of MKP2 in an animal model of renal fibrosis and evaluated the potential role of MKP2 in tubular EMT induced by TGF-β1. We found that the expression of MKP2 was up-regulated in the tubular epithelial of unilateral ureter obstruction rats. Meanwhile, we also demonstrated that TGF-β1 up-regulated MKP2 expression in NRK-52E cells during their EMT phenotype acquisition. Importantly, overexpression of MKP2 inhibited c-Jun amino terminal kinase (JNK) signaling and partially reversed EMT induced by TGF-β1. Moreover, reducing MKP2 expression enhanced JNK phosphorylation, promoted the E-cadherin suppression and induced α-SMA expression and fibronectin secretion in response to TGF-β1, which could be rescued by a JNK inhibitor. These results provide the first evidence that MKP2 is a negative feedback molecule induced by TGF-β1, and MKP2 overexpression inhibits TGF-β1-induced EMT through the JNK signaling pathway. MKP2 could be a promising target to be used in gene therapy for renal fibrosis.

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The Expression of TRIM6 Activates the mTORC1 Pathway by Regulating the Ubiquitination of TSC1-TSC2 to Promote Renal Fibrosis

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2020.616747 ◽

2021 ◽

Vol 8 ◽

Author(s):

Weiwei Liu ◽

Yang Yi ◽

Chuanfu Zhang ◽

Baojuan Zhou ◽

Lin Liao ◽

...

Keyword(s):

Renal Fibrosis ◽

Nuclear Translocation ◽

Epithelial Mesenchymal Transition ◽

Kidney Diseases ◽

Mtor Pathway ◽

Mesenchymal Transition ◽

Regulatory Pathways ◽

Mtorc1 Pathway ◽

Hk2 Cells

Renal fibrosis is considered as the final pathway of all types of kidney diseases, which can lead to the progressive loss of kidney functions and eventually renal failure. The mechanisms behind are diversified, in which the mammalian target of rapamycin (mTOR) pathway is one of the most important regulatory pathways that accounts for the disease. Several processes that are regulated by the mTOR pathway, such as autophagy, epithelial-mesenchymal transition (EMT), and endoplasmic reticulum (ER) stress, are tightly associated with renal fibrosis. In this study, we have reported that the expression of tripartite motif-containing (TRIM) protein 6, a member of TRIM family protein, was highly expressed in renal fibrosis patients and positively correlated with the severity of renal fibrosis. In our established in vitro and in vivo renal fibrosis models, its expression was upregulated by the Angiotensin II-induced nuclear translocation of nuclear factor-κB (NF-κB) p50 and p65. In HK2 cells, the expression of TRIM6 promoted the ubiquitination of tuberous sclerosis proteins (TSC) 1 and 2, two negative regulators of the mTORC1 pathway. Moreover, the knockdown of TRIM6 was found efficient for alleviating renal fibrosis and inhibiting the downstream processes of EMT and ER in both HK2 cells and 5/6-nephrectomized rats. Clinically, the level of TRIM6, TSC1/2, and NF-κB p50 was found closely related to renal fibrosis. As a result, we have presented the first study on the role of TRIM6 in the mTORC1 pathway in renal fibrosis models and our findings suggested that TRIM6 may be a potential target for the treatment of renal fibrosis.

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Hydroxysafflor Yellow A Ameliorates Renal Fibrosis by Suppressing TGF-β1-Induced Epithelial-to-Mesenchymal Transition

PLoS ONE ◽

10.1371/journal.pone.0153409 ◽

2016 ◽

Vol 11 (4) ◽

pp. e0153409 ◽

Cited By ~ 8

Author(s):

Naping Hu ◽

Jialin Duan ◽

Huihui Li ◽

Yanhua Wang ◽

Fang Wang ◽

...

Keyword(s):

Renal Fibrosis ◽

Epithelial To Mesenchymal Transition ◽

Hydroxysafflor Yellow A ◽

Mesenchymal Transition ◽

Tgf Β1

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Transplantation of Telocytes Attenuates Unilateral Ureter Obstruction-Induced Renal Fibrosis in Rats

Cellular Physiology and Biochemistry ◽

10.1159/000489445 ◽

2018 ◽

Vol 46 (5) ◽

pp. 2056-2071 ◽

Cited By ~ 3

Author(s):

Long Zheng ◽

Long Li ◽

Guisheng Qi ◽

Mushuang Hu ◽

Chao Hu ◽

...

Keyword(s):

Growth Factor ◽

Protective Effect ◽

Renal Fibrosis ◽

Transforming Growth Factor ◽

Kidney Tissue ◽

Collagen I ◽

Enzyme Linked Immunosorbent Assay ◽

Mrna Levels ◽

Mesenchymal Transition ◽

Tgf Β1

Background/Aims: Previous studies imply that telocytes may have a protective effect on fibrosis in various organs, including the liver, colon, and heart. The effect of telocytes on renal fibrosis remains unknown. Herein, this study was designed to investigate the effect of telocytes on renal fibrosis and the potential mechanisms involved. Methods: In a unilateral ureteral obstruction (UUO)-induced renal fibrosis model, telocytes were injected via the tail vein every other day for 10 days. The degree of renal damage and fibrosis was determined using histological assessment. The expression of collagen I, fibronectin, epithelial-mesenchymal transition markers, and Smad2/3 phosphorylation was examined by western blot analyses. Real-time PCR and enzyme-linked immunosorbent assay were performed in vivo to detect the levels of transforming growth factor (TGF)-β1 and various growth factors. Results: Telocytes attenuated renal fibrosis, as evidenced by reduced interstitial collagen accumulation, decreased expression of fibronectin and collagen I, upregulation of E-cadherin, and downregulation of α-smooth muscle actin. Furthermore, telocytes decreased serum TGF-β1 levels, suppressed Smad2/3 phosphorylation, and increased the expression of hepatocyte growth factor (HGF) in rat kidney tissue following UUO. Blockage of HGF counteracted the protective effect of telocytes on UUO-treated kidneys. Through the detection of HGF mRNA levels in vitro, we found that telocytes had no effect on HGF expression compared with renal fibroblasts. Conclusion: Telocytes attenuated UUO-induced renal fibrosis in rats, likely through enhancing the expression of HGF in an indirect manner.

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