Change In Selenoprotein S1 Gene Expression And Its Potential Effection On Septic Mouse

OBJECTIVE Septic shock and sequential multiple organ failure remain the cause of death in septic patients.Selenoprotein S1(SEPS 1),a novel gene involved in the stress response of endoplasmic reticulum and inflammation control.Recent results provide a direct mechanistic link between SEPS1 and the production of inflammatory cytokines,suggesting SEPS1 may play a major role in the mediation of inflammation and some immunological disorder.We therefore examined the change in SEPS1 gene expression and its potential effection in septic mouse.Synthetic small interfering RNAs (siRNA)specifically suppress gene expression by RNA interference.Therefore,we evaluated the therapeutic efficacy of SEPS1 siRNA in an endotoxic shock.METHODS Endotoxic shock was induced by LPS attack in BALB/c mice. SEPS1 protein expression changes were detected in 0h,6h,12h,24h,48h,72h and 96h after LPS(lipopolysaccharides)abdominal injection.Cytokines interleukin-6(IL-6), tumor necrosis factor(TNF-α)contents,and NF-κB were determined using Enzyme-linked immunosorbent assay(ELISA)in the same time point.Further studies were conducted with gene silence technique.In vivo delivery of siRNA was performed by using a transfection reagent(Superfusion X).As a negative control,animals received non-sense(scrambled)RNA.Study was conducted through three groups:H group (sepsis),K group(sepsis and scrambled RNA)and L group(sepsis and siRNA). Scrambled RNA and siRNA were injected in K group and L group correspondingly 12h before LPS abdominal injection.IL-6 contents.TNF-αcontents and NF-κB were was determined using ELISA.SEPS1 expression was detected using Western blot.All the data were compared among three groups.RESULTS The first part showed dynamic changes in serum level of biochemical indicator and cytokines in septic mouse.GPT,GOT,BUN,Cr,LDH,CK and CK-MB were markedly increased after endotoxic shock was induced by LPS injection(P＜0.05). Peak of damage was during 6h～24h.IL-6 and TNF-αwere elevated in the first 24h,and SEPS1 protein expression were enhanced at the same time.The second part show that organ damage was worsen after SEPS1 siRNA was deliveried using a transfection reagent(Superfusion X).IL-6 and TNF-αwere elevated more in L group than that of H group.SEPS1 protein expression in liver tissue was strongly suppressed by treatment with SEPS1 siRNA.L group(sepsis and siRNA)was deteriorated more than H group.CONCLUSIONS Gene silencing of SEPS1 with siRNA provided negative effect against LPS endotoxic shock.Biochemical indicators were deterioration strongly, inflammatory response was enhanced and Selenoprotein S1(SEPS1)was down regulated,which suggest,at least in part,the protective effect of SEPS1 on septic mouse.