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.