The antifibrogenic effect of hepatocyte growth factor (HGF) on renal tubular (HK-2) cells is dependent on cell growth

Abstract

Although several reports suggest an antifibrogenic effect of hepatocyte growth factor (HGF), an increased deposition of matrix induced by HGF has also been reported. These conflicting effects could result from a diverse proliferative state of the target cells. Aim of the present study was to evaluate HGF effects on growth arrested (quiescent) and actively proliferating renal tubular epithelial (HK-2) cells. HK-2 cells were cultured in RPMI medium either on agarose gel or on plastic surface in order to inhibit or to allow cell proliferation. Cells were incubated with RPMI containing HGF (50 ng/ml) for 24 h at 37 degrees C. Untreated HK-2 were used as control. After 24 h of incubation, cells were counted by Coulter counter. (alpha2)IV collagen, transforming growth factor-beta (TGF-beta), Tissue inhibitor of metalloproteases (TIMP1 and 2) mRNA levels were determined by RT-PCR. The production of type IV collagen, c-met, proliferating cell nuclear antigen (PCNA), and SnoN, a transcriptional Smad corepressor and thus a TGF-beta inhibitor, was evaluated by ELISA or western blotting. MMP-9 and 2 gelatinolytic activity was studied by zymography. Treatment with HGF did not increase HK-2 cell number and PCNA synthesis when the cells were grown on agarose as it did for cells grown on plastic surface. HGF increased (alpha2)IV collagen in proliferating cells whereas it reduced (alpha2)IV collagen and c-met synthesis in growth arrested cells. HGF treatment increased TGF-beta and TIMP-2 in proliferating cells while reduced TIMP-1 mRNA levels of quiescent cells. Furthermore, production of the co repressor SnoN was significantly decreased by HGF in proliferating cells. Quiescent and proliferating HK-2 showed a different pattern of metalloproteases activity with a prevalence of MMP2 in quiescent and MMP9 in proliferating cells. In summary, HGF showed opposite effects on growth arrested and proliferating HK-2 cells favouring matrix deposition in the latter with increasing expression of collagen, TIMP-1 and TGF-beta. Our results demonstrate that the proliferative state of target cells may influence the effects of HGF on extracellular matrix turnover in HK-2 cells.

Mutant MMP-9 and HGF Gene Transfer Enhance Resolution of CCl4-Induced Liver Fibrosis in Rats: Role of ASH1 and EZH2 Methyltransferases Repression

“…It had been demonstrated that HGF increases production of ECM in renal cells [50] and induces profibrotic changes in peritoneal cells [51]. Based on the observation that there is a relationship between cell proliferation and production of ECM molecules [52] and that the effects and expression of growth factors may be altered by ECM components [53], Esposito showed that HGF affects quiescent and proliferating renal tubular epithelial (HK-2) cells differently, favoring deposition of ECM in proliferating and matrix degradation in quiescent HK-2 cells [54]. Clinically, antifibrotic therapy often is initiated without control of the underlying disease process and therefore liver cells would be in a proliferative state.…”

Human Wharton’s jelly-derived mesenchymal stromal cells reduce renal fibrosis through induction of native and foreign hepatocyte growth factor synthesis in injured tubular epithelial cells

“…However, Esposito et al . [34] found that HGF acts as anti-fibrotic factor reducing TGF effect only on quiescent renal tubular (HK-2) cells. On proliferating cells, HGF increases TGF expression.…”

Insulin-like growth factor binding protein 7 and tissue inhibitor of metalloproteinases-2: differential expression and secretion in human kidney tubule cells

“…Expression has also been reported in proximal tubule cells, but primarily only in response to insults, mitogens, or second messengers (14,20,41,45,62,63). There is a dearth of information regarding IGFBP7 in the kidney, and what is available is contradictory, showing expression in the glomerulus and alternatively in distal and proximal tubule cells (17,35,42,65,72).…”