Effect of ligand of peroxisome proliferator-activated receptor gamma on the biological characters of hepatic stellate cells.

AIM: To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma (PPARgamma), on the expression of PPARgamma in hepatic stellate cells (HSCs) and on the biological characteristics of HSCs. METHODS: The activated HSCs were divided into three groups: control group, 3 micromol/L rosiglitazone group, and 10 micromol/L rosiglitazone group. The expression of PPARgamma, alpha-smooth muscle actin (alpha-SMA), and type I and III collagen was detected by RT-PCR, Western blot and immunocytochemical staining, respectively. Cell proliferation was determined with methylthiazolyltetrazolium (MTT) colorimetric assay. Cell apoptosis was demonstrated with flow cytometry. RESULTS: The expression of PPARgamma at mRNA and protein level markedly increased in HSCs of 10 micromol/L rosiglitazone group (t value was 10.870 and 4.627 respectively, P<0.01 in both). The proliferation of HSCs in 10 micromol/L rosiglitazone group decreased significantly (t = 5.542, P<0.01), alpha-SMA expression level and type I collagen synthesis ability were also reduced vs controls (t value = 10.256 and 14.627 respectively, P<0.01 in both). The apoptotic rate of HSCs significantly increased in 10 micromol/L rosiglitazone group vs control (chi(2) = 16.682, P<0.01). CONCLUSION: By increasing expression of PPARgamma in activated HSCs, rosiglitazone, an agonist of PPARgamma, decreases alpha-SMA expression and type I collagen synthesis, inhibits cell proliferation, and induces cell apoptosis.

[Regulation of hepatic stellate cell activation by interleukin-10/platelet derived growth factor/mitogen-activated protein kinase pathway].

OBJECTIVE: To investigate the regulatory effect of interleukin-10 (IL10) on the activation of hepatic stellate cells (HSC) through platelet derived growth factor (PDGF) and mitogen-activated protein kinase (MAPK) pathways. METHODS: HSC were divided randomly into 4 groups. Group 1 served as a control. HSC were incubated with 1 ng/ml, 5 ng/ml, and 25 ng/ml IL-10 in groups 2, 3 and 4. RT-PCR and western blot were used to detect the expression of PDGF and MAPK protein ERK and p38 and alpha-SMA. RESULTS: Compared with the control group, expressions of ERK, p38 and alpha-SMA of groups 2, 3 and 4 were significantly lower (F values were 240.47, 21.39, 28.86 respectively. IL-10 inhibited PDGF and MAPK protein ERK and p38 and alpha-SMA expression in a dose-dependent way. CONCLUSION: IL-10 inhibits activation of HSC through the PDGF/MAPK pathway.

[An in vivo study on interlukin-10 inhibiting the expression and secretion of collagen I and IV in hepatic stellate cells].

OBJECTIVES: To investigate the effect of interlukin-10 (IL-10) on expression and secretion of collagen I, IV in rat's hepatic stellate cells (HSC) of livers injured by CCl4. METHOD: The adenovirus vector encoded IL-10 gene was used to transfect rats with liver injury via the caudal veins. HSC were isolated and purified from the rat livers by collagenase IV perfusion and density gradient centrifugation with Nycodenz. The expression of collagen I, IV mRNA in HSC was detected by semi-quantitative RT-PCR method and the secretion of collagen I, IV in culture serum of HSC by ELISA method. The quantity of collagen was measured in the van Gieson stained histological liver preparations. RESULTS: The expression and secretion of collagen I, IV in the adenovirus vector encoding IL-10 gene group were significantly lower than those in the adenovirus vector without IL-10 gene group and the control group (P < 0.05). The quantity of collagen in the treatment group was lower than that in the control group. CONCLUSION: IL-10 can inhibit collagen I, IV expression and secretion in rat HSC.

[Downregulation of transforming growth factor-beta1 and platelet-derived growth factor gene expression by interleukin-10 in murine hepatic stellate cells in response to experimental liver injury].

OBJECTIVE: To investigate the effect of interleukin-10 (IL-10) on the expression of transforming growth factor-beta(1) (TGFbeta(1)) and platelet-derived growth factor (PDGF) in hepatic stellate cells (HSC) during liver injury. METHODS: The adenovirus vector (the titer was 1 x 10(7) efu/ml) encoded IL-10 gene was used to transfect the rat via the vein of caudal. At the same time, CCl(4) was injected into rat by a hypodermic injection. These processes went on twice a week. After eight weeks, the liver were perfused with collagenase IV and purified by density gradient centrifugation with Nycodenz for separate HSC. The level of IL-10 was measured by ELISA method; The expression of PDGF and TGFbeta(1) in HSC was detected by semi-quantitative RT-PCR and Western-blot methods. RESULTS: The level of IL-10 in therapy group (adenovirus vector encoding IL-10 gene group) was higher than that in non-therapy group (adenovirus vector without IL-10 gene and PBS group); The expression of TGFbeta(1) mRNA, TGFbeta(1) protein and PDGF mRNA, PDGF protein in therapy group were significantly lower than that in non-therapy group (P < 0.05). CONCLUSION: Downregulating the TGFbeta(1) and PDGF expression could be the passageway by which IL-10 alleviate the degree of proliferation and activation in hepatic stellate cells.

Expression of IARS2 gene in colon cancer and effect of its knockdown on biological behavior of RKO cells.

OBJECTIVE: To investigate the expression level of IARS2 gene in colon cancer tissues and various cell strains of the cancer; to explore cytologically the effect of IARS2 gene knockdown on proliferation, apoptosis and cell cycle of RKO cells in the cancer. METHODS: Real-time, fluorescence-based quantitative PCR (qPCR) was used to detect the expression of IARS2 gene in human colon cancer and surrounding tissues and in various cell strains of the cancer; the RNA interference target of IARS2 gene was designed and the target was detected by Western blot; the IARS2-siRNA lentiviral vector was established and used to infect the RKO cells of colon cancer; qPCR was employed to determine the effect of gene knockdown; changes of the RKO cells in growth, apoptosis, cell cycle and clone formation were observed after IARS2 gene knockdown. RESULTS: The expression of IARS2 gene was higher in human colon cancer tissues than in surrounding tissues; there was expression of IARS2 gene in colon cancer cells, and the expression level of IARS2 gene mRNA was higher in the RKO cells than in the SW480, HCT116, DLD1, HT-29 and SW620 cells. After infection of the RKO cells with IARS2-siRNA lentivirus, the expression of IARS2 gene was inhibited in the level of mRNA; proliferation rate of the RKO cells was significantly inhibited; the G1 phase arrest of the RKO cells was increased with less RKO cells in S phase; the apoptotic RKO cells increased significantly; and the number of colonies of the RKO cells reduced. CONCLUSION: The expression of IARS2 gene is different in human colon cancer and surrounding tissues; after knockdown of IARS2 gene, proliferation of the RKO cells is inhibited; there are more cells in G phase and fewer cells in S phase; apoptosis of cells is increased; and formation of colonies is reduced. IARS2 gene is probably a cancer-promoting gene.