Profibrotic effects of angiotensin II and transforming growth factor beta on feline kidney epithelial cells

Abstract

Objectives The aim of this study was to evaluate the role of angiotensin II (AT-II) and its main mediator, transforming growth factor beta 1 (TGF-β1), in the development of feline renal fibrosis. Methods Expression of marker genes indicating epithelial-to-mesenchymal transition (EMT), profibrotic mediators and matricellular proteins was measured in feline kidney epithelial cells (Crandell Rees feline kidney [CRFK] cells) after incubation with AT-II and/or TGF-β1. Results Cells incubated with TGF-β1 or the combination of TGF-β1 with AT-II showed clear EMT with more stretched fibroblastic cells, whereas the cells incubated without TGF-β1 and AT-II (control) showed more epithelial cells. Gene expression of collagen type I ( COL1), tenascin-C ( TNC), trombospondin-1 ( TSP-1), connective tissue growth factor ( CTGF) and alpha-smooth muscle actin ( α-SMA) increased significantly after incubation of the CRFK cells with TGF-β1 or TGF-β1 in combination with AT-II for 12 h. As incubation of the CRFK cells with only AT-II did not show any significant rise in gene expression of the above-mentioned genes, this was further investigated. In contrast to healthy feline kidney tissue, CRFK cells showed almost no expression of the AT-II type 1 (AT1) receptor. Conclusions and relevance TGF-β1 significantly induced expression of the EMT marker gene α-SMA, profibrotic mediator CTGF, and fibrogenic proteins COL1, TNC and TSP-1 in CRFK cells. The effect of TGF-β1 on myofibroblast formation was also observed by the stretched appearance of the CRFK cells. As CRFK cells expressed almost no AT1 receptors, this cell line proved not suitable for testing the efficacy of drugs that interact with the AT1 receptor. As AT-II stimulates the effects of TGF-β1 in mammals, the results of this study suggest an indirect profibrotic effect of AT-II besides the demonstrated profibrotic effect of TGF-β1 and thus the development of feline renal fibrosis. Modulation of EMT or proliferation of myofibroblasts could serve as a diagnostic tool and a novel therapeutic target to inhibit renal fibrogenesis, and could possibly serve in the therapy of feline renal fibrosis.

An Insight on Multicentric Signaling of Angiotensin II in Cardiovascular system: A Recent Update

“…Ang II-dependent connective tissue growth factors (CTGF) and transforming growth factor-β (TGF-β) are initial pro-fibrotic mediators involved in cardiac fibrosis ( Wong et al, 2018 ; van Beusekom and Zimmering, 2019 ). The expression of CTGF and TGF-β are interlinked.…”

Inhibition of Crandell-Rees Feline Kidney cell proliferation by X-ray-induced senescence

“…Recently, CRFK cells have been reported to have the characteristics of fibroblast, particularly regarding morphology, biochemistry, and molecular biology, although CRFK cells have been established as an epithelial cell line [ 21 ]. Moreover, van Beusekom et al [ 31 ] reported that TGF-β1 changed the morphology of CRFK cells from an epithelial phenotype to a fibroblastic phenotype and that it significantly induced the expression of some EMT marker genes in CRFK cells, suggesting that CRFK cells can undergo EMT. In the present study, senescence appeared more important than apoptosis for growth suppression in irradiated CRFK cells.…”

Protective Effect of Natural Antioxidant Compounds on Methimazole Induced Oxidative Stress in a Feline Kidney Epithelial Cell Line (CRFK)

“…As the kidney is a target organ of MMI-induced toxicity, an immortalized cell line derived from the renal cortex of a normal cat (CRFK) was used [ 25 ]. Although uncertainty has been suggested about the epithelial vs. mesenchymal phenotype of CRFK cells [ 26 ], they have been originally described as epithelial [ 25 ], and they are widely used accordingly [ 27 , 28 ].…”