RNA-Seq Analysis Reveals A Critical Role Of Differentially Expressed Genes During Adipogenesis Of 3T3-L1

Adipocytes are the main constituent of adipose tissue and are considered to be a corner stone in the homeostatic control of whole body metabolism.Adipogenesis is the process during which fibroblast like preadipocytes developed into differentiated adipocytes and is a well-orchestrated multistep process that requires the sequential activation of various transcription factors,such as the peroxisome proliferator activated receptor-?(PPAR-?)and CCAAT/enhancer-binding protein(C/EBP)gene family.In this study,we performed RNA sequencing(RNA-Seq)at the preadipocytes(D0)and differentiated adipocytes(D13)of 3T3-L1 in order to characterize the transcriptional events regulating differentiation and function.Compared to the preadipocytes(D0),4,443 genes were identified as differentially expressed genes(DEGs)with a fold change of ? 2.0 at the differentiated adipocytes(D13).Furthermore,based on the RNA-Seq data,we found that the expression of Methylsterol monooxygenase 1(MSMO1)is dramatically down-regulated during adipogenesis of 3T3-L1 preadipocytes.This suggested MSMO1 may be a novel regulator during adipogenesis,but the role of MSMO1 in adipogenesis has yet been reported.Therefore,we investigated its role in adipogenesis.We report here that knockdown of MSMO1 expression by MSMO1 small interfering RNA(siRNA)resulted in a stimulation of adipogenesis and adipogenic genes expression.Conversely,overexpression of MSMO1 inhibited expression of adipogenic specific genes and lipid droplet formation in 3T3-L1 differentiated adipocytes.These results suggested that MSMO1 may plays a negative role during 3T3-L1 adipogenesis.In addition,we also found that the expression of NAD(P)H steroid dehydrogenase-like(NSDHL)was downregulated in MSMO1-knockdown 3T3-L1,suggesting that the suppression of adipogenesis caused by MSMO1 may via the NSDHL pathway in 3T3-L1.Bioinformatics modeling of interactions for the sterol pathway genes in eukaryotes allowed us to hypothesize and then extensively validate a synergized role for MSMO1 and NSDHL in controlling adipogenesis.Meanwhile,our results demonstrate that NSDHL is a critical regulator of adipogenesis in 3T3-L1 that acts in the early stages of adipogenesis.And it may partake in the regulation of cell proliferation and cell cycle.Collectively,our findings indicate that MSMO1 and NSDHL are novel modulators of adipogenesis,which presents a novel strategy for further study into the molecular mechanism of adipogenesis.