The Expression And Role Of Sept4 And MiR-454 In Mouse Fibrotic Livers Infected With Schistosoma Japonicum

Objective We attempted to investigate the effect and role of Sept4 in mouse fibrotic livers infected with Schistosoma japonicum. We also attempted to observe the expression of miR-454 in HSCs and fibrotic livers and to study the effect and mechanism of miR-454 on activation of HSCs.Methods1. ICR mice(n=30) were adaptive fed for 1 week and randomly divided into 3 groups, named as PBS group(infected with Schistosoma japonicum and treated with PBS), Ad-GFP group(infected with Schistosoma japonicum and treated with Ad-GFP), Ad-Sept4 group(infected with Schistosoma japonicum and treated with Ad-Sept4). PBS group, Ad-GFP group and Ad-Sept4 group were given praziquantel(PZQ)(250mg/kg/24h) at 12 w post-infection to kill adult worms, and then treated with PBS, Ad-GFP and Ad-Sept4, respectivelly. All mice were killed at 15 w post-infection, and the changes in the fibrotic livers were detected via HE staining and Sirius red staining. The expression of Sept4, pro-collα1(I), α-SMA, cleaved-caspase-3, TGF-β1 and IL-6 was detected by Western Blot and qRT-PCR. And TUNEL analysis was used to observe the apoptosis phenomenon in the fibrotic livers treated with or without Ad-Sept4.2. ICR mice(n=16) were adaptive fed for 1 week and randomly divided into 2 groups, named as normal group and infection group(infected with Schistosoma japonicum). Mice were sacrificed at 8w post-infection. We detected the expression of miR-454 in fibrotic livers and in HSCs via qRT-PCR. We observed the effect of miR-454 on proliferation and cell cycle of HSCs by MTT analysis and flow cytometry, and we also observed the role of miR-454 on HSCs activation by Western Blot.Results1. Ad-Sept4 could ameliorate liver fibrosis, as detected by HE staining and Sirius red staining. The number of TUNEL-positive cells was increased in the Ad-Sept4 treated group, compared with the Ad-GFP group. The expression of Sept4 and cleaved-caspase-3 was increased, and the expression of α-SMA, pro-collα1(I), TGF-β1 and IL-6 was decreased, compared with that expressed in the Ad-GFP group.2. Expression of miR-454 was down-regulated in the activated HSCs and in the livers infected with Schistosoma japonicum. miR-454 did not affect the proliferation and cell cycle of activated HSCs. However, over-expression of miR-454 could inhibit the expression of α-SMA and Smad4.3. miR-454 mimics could inhibit the Smad4 luciferase activity in the activated HSCs.Conclusions1. Ad-Sept4 can inhibit the development of liver fibrosis induced by Schistosoma japonicum.2. Expression of mi R-454 is down-regulated in activated HSCs and in the fibrotic livers infected with Schistosoma japonicum.3. Over-expression of miR-454 can inhibit the activation of HSCs by inhibiting the activity of 3’ UTR domain of Smad4.