Silencing SOCS3 could inhibit TNF-α induced apoptosis in 3T3-L1 and mouse preadipocytes.

Tumor necrosis factor-alpha (TNF-α) is a pro-inflammatory cytokine involved in the apoptosis of many types of cells. In this study we demonstrated the effect of (suppressor of cytokine signalling-3) SOCS3 siRNA on TNF-α induced apoptosis in 3T3-L1 preadipocytes and mouse preadipocytes. 3T3-L1 preadipocytes and mouse preadipocytes were transfected with SOCS3 siRNA, and then the cells were treated with TNF-α at 100 ng/mL for 24 h. We used fluorescence microscope to observe morphological changes during apoptosis after Hoechst 33258 and PI staining. Quantitative PCR and Western blotting were used to measure the expression of apoptosis-associated gene c-myc, survivin, mcl-1, bcl-2, bax, NF-κB, and the key genes of the JAK/STAT3 pathway including SOCS1, SOCS2, JAK2, STAT3. Compared with control group, the number of cells apoptosis was decreased remarkably in SOCS3 siRNA group (P < 0.01). The expression of apoptotic suppressor genes c-myc, survivin, mcl-1, bcl-2 and NF-κB were up-regulated markedly (P < 0.01); in contrast, apoptotic gene bax was down-regulated (P < 0.05). Western blotting showed that the protein expressions of bcl-2 and NF-κB were increased remarkably (P < 0.01), while the protein expression of bax was decreased remarkably (P < 0.05). The expression of the JAK/STAT3 pathway key gene SOCS1 mRNA was down-regulated markedly (P < 0.05), but the key protein p-STAT3 was up-regulated (P < 0.05). Taken together, our data established that silenced SOCS3 can regulate the expression of apoptosis-associated genes via the JAK/STAT3 pathway, and effectively inhibit TNF-α induced apoptosis in 3T3-L1 preadipocytes and mouse preadipocytes.