Apoptosis of porcine Sertoli cells is inhibited by QKI-5 via regulating CASP8

QKI, a KH domain containing RNA binding, is an RNA-binding protein that is involved in cell proliferation and apoptosis through binding to the QKI response element (QRE) site of its target mRNA. And Caspase 8 (CASP8) and Caspase 3 (CASP3) play important roles in the pathway of apoptosis. The purpose of this study was to investigate the effect of QKI-5 on the apoptosis of Sertoli cells. The experimental results show that pig tissues contain QKI-5, QKI-6 and QKI-7. Overexpression of QKI-5 significantly decreased the mRNA expression of CASP8 (P < 0.05) and the protein expression of CASP8 (P < 0.05). On the contrary, inhibiting QKI-5 increased the expression of CASP8 significantly. Overexpression of QKI-5 significantly reduced the apoptosis of Sertoli cells and promoted cell growth (P < 0.05). Furthermore, QKI-5 specifically reduced the stability of CASP8 mRNA by binding QRE sites on CASP8. Our experiments provide preliminary evidence that QKI-5 induces Sertoli cells proliferation by inhibiting apoptosis, and this may be one of the factors promoting testicular development.