CTGF Inhibits the Differentiation of Chicken Preadipocytes via the TGFβ/Smad3 Signaling Pathway or by Inducing the Expression of ACTG2

Chicken is the main source of protein for humans in most parts of the world. However, excessive fat deposition in chickens has become a serious problem. This adversely affects the growth of chickens and causes economic losses. Fat formation mainly occurs through preadipocyte differentiation, and excessive fat deposition results from the accumulation of preadipocytes after differentiation. Our previous studies have found that the connective tissue growth factor (CTGF) may be an important candidate gene for fat deposition. However, its function and mechanism in preadipocyte differentiation are still unclear. In this study, the RT-qPCR and Western blot results showed that the expression of CTGF mRNA and protein in the abdominal adipose of lean chickens was significantly higher than that of fat chickens. Therefore, we studied the function and mechanism of the CTGF in the differentiation of chicken preadipocytes. Functionally, the CTGF inhibited the differentiation of chicken preadipocytes. Mechanistically, the CTGF mediated the TGFβ1/Smad3 signaling pathway, thereby inhibiting the differentiation of chicken preadipocytes. In addition, we used the unique molecular identifier (UMI) RNA-Seq technology to detect genes that can be regulated by the CTGF in the whole genome. Through transcriptome data analysis, we selected actin gamma 2 (ACTG2) as a candidate gene. Regarding the function of the ACTG2 gene, we found that it inhibited the differentiation of chicken preadipocytes. Furthermore, we found that the CTGF can inhibit the differentiation of preadipocytes through the ACTG2 gene. In summary, this study found the CTGF as a new negative regulator of chicken preadipocyte differentiation. The results of this study help improve the understanding of the molecular genetic mechanism of chicken adipose tissue growth and development and also have reference significance for the study of human obesity.