Fasudil Inhibits Epithelial-Myofibroblast Transdifferentiation of Human Renal Tubular Epithelial HK-2 Cells Induced by High Glucose

Abstract

Renal fibrosis is a crucial pathologic process underlying diabetic nephropathy (DN). Central to this process is the epithelial-mesenchymal transformation (EMT) of tubular epithelial cells. Fasudil, a Rho-associated coiled-coil forming protein serine/threonine kimase (ROCK) inhibitor, protects against renal fibrosis in a variety of renal injury models. However, fasudil's effects on renal fibrosis in DN remain unknown. The aim of the present study was to investigate the effects of fasudil on high glucose-induced EMT in human renal tubular epithelial (HK-2) cells. HK-2 cells were exposed to 5.5 or 60 mmol/L d-glucose for 72h, or to mannitol (osmotic control). RhoA activity was assessed using a RhoA pull-down assay, and ROCK activity was determined by myosin phosphatase target subunit-1 (

Arg tyrosine kinase modulates TGF-β1 production in human renal tubular cells under high-glucose conditions

“…Therefore, in our cellular model under high-glucose conditions, Arg kinase downregulation could activate the RhoA-ROCK signaling by reducing RhoA inhibition induced by p190RhoGAPA. The activation of this signaling would explain the increase of stress fibers (Hernández et al, 2004) and TGF-β1 production (Gu et al, 2013).…”

“…However, what is the main cellular type responsible for extracellular matrix deposition is still a matter of debate. Some studies have shown that tubular cells might undergo an in vitro epithelialmesenchymal transition (EMT) and have a direct role in tubulointerstitial fibrosis development (Lee and Han, 2010;Hills et al, 2012;Gu et al, 2013). However, conclusive evidence of a full EMT process in vivo is a controversial point.…”

“…Remarkably, it has been described that c-Abl and Arg tyrosine kinases associate with and phosphorylate the proteasome PSMA7 subunit with consequent inhibition of proteasome activity (Liu et al, 2006). Arg is also involved in some aspects of the EMT process, like cell migration and cytoskeleton modulation through the RhoA-ROCK pathway (Hernández et al, 2004;Peacock et al, 2007;Bianchi et al, 2013), which is also involved in TGF-β secretion in a high-glucose-treated HK-2 cell line (Gu et al, 2013). Based on these data, in the current study we analyzed the involvement of Arg tyrosine kinase in the production of TGF-β1 induced in well-characterized human primary tubular cell cultures (Perego et al, 2005;Bianchi et al, 2010;Cifola et al, 2011) by treatment with high glucose, which also induced some phenotypical and molecular changes in these tubular cells.…”

Rapamycin inhibits epithelial‐to‐mesenchymal transition of peritoneal mesothelium cells through regulation of Rho GTPases

“…The Rho GTPases (RhoA, Rac1, and Cdc42) have been implicated in the regulation of cell motility, actin cytoskeleton, and EMT [30,31]. Because emerging evidences demonstrated that treatment with rapamycin inhibited RhoA and Rac1 activity during EMT [29,33], we hypothesized that mTOR may regulate cell migration and actin reorganization in EMT of RPMCs at least in part by mediating the activity of the small GTPases.…”

“…Generally, RhoA stimulates formation of actin stress fibers and focal adhesions, Rac1 promotes formation of lamellipodia, and Cdc42 induces formation of filopodia [29]. It has been shown that Rho GTPases play important roles in EMT [30][31][32]. Further studies investigated the relationship between mTOR and Rho GTPases (RhoA, Rac1, and Cdc42) during EMT [33,34].…”