The Expression Of HSP47 In Renal Tissues Of Chronic Renal Disease Patients And Its Relationship With TGF-β1

Objective: To investigate the role of Heat Shock Protein 47(HSP47) and its relationship with TGF- β 1 during the development of renal fibrosis.Methods:Renal tissue examine. Fifty patients with chronic renal disease were divided into three groups according to the glomerular sclerosis and renal interstitial fibrosis score. 20 patients were in light fibrosis group(score=0 to 2), 15 in middle fibrosis group(score=3 to 5), and 15 in severe fibrosis group(score=6 to 8). 5 specimens of normal renal tissue were obtained from microscopically normal sections of renal cell carcinoma patients and served as control group. Heat shock protein 47(HSP47), type IV collagen, transforming growth factor-β1(TGF-β l)and Alpha smooth muscle actin(α -SMA) in renal specimens were examined by immunohistochemical staining and computer image analysis system. Clinical data of the 50 patients were collected when they received biopsy. The relationship among the expression of of HSP47, type IV collagen (COL-IV) , TGF- β 1 and a -SMA in renal tissue and the score of renal fibrosis, serum creatinie (Scr) and clearance of creatinie (Ccr) was analyzed using SPSS 10.0 system for windows.Cell culture. Normal human renal fibroblast were isolated from nephrectomized microscopically normal renal tissue of malignant kidney tumor and cultured in vitro. Recombinant TGF- β 1 was added to the culture medium to observe the influence of TGF-β 1 on the expression of HSP47 and type I collagen (CLO-I). The expression of HSP47 in the renal fibroblasts was detected by immunocytochemical staining. The mRNA level of HSP47 and type I collagen was detected by reverse transcriptase polymerase chain reaction(RT-PCR).Results:Renal tissue examine results. (1) The HSP47 expression: In the normal control group, the level of HSP47 expression was very low in the renal tubular epithelial cell. Incontrast, there was high HSP47 expression in the tubular epithelial cells, renal interstitial tissue, glomerular epithelial and mesangial cells of trial groups. The intensity of HSP47 expression was positively correlated with the degree of glomerulosclerosis and tubulointerstitial injury(P<0.01). (2) The COL-IV, TGF-Pi and a-SMA expression: In trial group, there was higher expression of COL-IV, TGF- 1 and a -SMA than that of control group(P<0.01). In renal fibrotic tissues, the expression pattern of TGF- 1 was similar to HSP47. (3) The expression level of HSP47 was positively correlated with COL-IV, TGF- 0 1 and a -SMA. The correlation index of HSP47 with COL-IV was highest (r=0.871, p<0.01). (4) The expression level of HSP47 was positively correlated with renal fibrosis score (r=0.747, P<0.01) and Scr(r=0.517, P<0.01), and negatively correlated with Ccr (r=-0.667, P0.01).Cell culture results. (1) Immunocytochemistry results showed that primary cultured renal cells were positively stained for vimentin, but not for keratin nor CD34, and cells showed fusiform shape. It proved that the cultured cells were human renal fibroblasts. (2) The cultured fibroblasts without TGF- 1 stimulation had very low HSP47 expression. In contrast, those cultured fibroblasts sitimulated with the TGF- 1 had a significant higher level of HSP47 expression. (3) TGF-0 l,in the range of 0.1 ng/mL to 5ng/mL, increased the expression level of HSP47 and COL-I mRNA in a dose-depended manner.Conclusion: (1) In the chronic renal disease patients, increased HSP47 expression correlates with renal fibrosis. This phenomenon suggested that HSP47 associated with the collagen production may play an important role in the development of renal fibrosis. (2) In the chronic renal disease patients, TGF- 1 promoted renal fibrosis by enhancing HSP47 and collagen expression in some degree.