Effect of the Porcine STC-1 Gene on Autophagy and Mitochondrial Function as Induced by Serum Starvation

Abstract

Stanniocalcin-1 (STC-1) is a glycoprotein hormone involved in calcium/phosphorus metabolism and direct inhibition of bone and muscle growth. The aim of this study was to investigate the STC-1 gene with respect to the regulatory mechanisms of porcine growth metabolic pathways involving autophagy. Western blotting was used to detect the expression of autophagy and mitochondrial function-related proteins, and flow cytometry was used to detect mitochondrial function-related. Changes in the autophagosome and mitochondrial were observed by electron microscopy. The expression of the autophagy-related proteins was detected by confocal microscopy. The results showed that Pink1, Parkin and LC3B expression was increased; SQSTM1/P62 expression was reduced. Electron microscopy revealed that the cells in the serum starvation group all produced autophagosomes. The fluorescence intensity of GFP-LC3B and GFP-Parkin increased. The Bax/Bcl-2 ratio, Pink1 and Parkin protein levels were profoundly reduced in the STC-KO. In addition, the increase in Mfn2, OPA1, DRP1 and LC3B proteins was attenuated; the increase in the apoptosis rate and amount of active oxygen was attenuated; the decrease in membrane potential; the decrease in ATP was reversed; the fluorescence intensity of GFP-LC3B and GFP-Parkin was increased. These results indicate that autophagy can be caused by serum starvation. Knocking out the porcine STC-1 gene had an obvious antiapoptotic effect on cells, the inhibition of serum starvation-induced autophagy. This is the first study to show that the porcine STC-1 gene confers self-protection in the absence of nutrients. To provide a theoretical basis for studying the effect of STC-1 on pig growth and development.

Keywords: Autophagy; Mitochondria; STC-1 gene; Serum starvation; Swine.