IGFBP7 downregulation or overexpression effect on bovine preadipocyte differentiation.

The insulin-like growth factor binding-protein 7 (IGFBP7) has binding affinities to IGFs and is able to either positively or negatively regulate the IGFs signaling pathway. It also plays a crucial role in cell growth, differentiation and development in an IGF-independent manner. Herein, we investigated the specific regulation of the gene encoding for IGFBP7during the differentiation process of the adipocyte cells of the Yan Yellow Cattle by interfering with or by overexpressing the IGFBP7 gene. As a result, we found that the mRNA expression levels of IGFBP7 were significantly increased during the formation of progenitor cells. In addition, the expression levels of the lipoprotein lipase (LPL) and transcription factors (PPARγ, C/EBPα) were also significantly increased. IGFBP7 gene overexpression and RNA interfering promoted and inhibited respectively the lipid accumulation and triglyceride production in mature adipocytes, and the expression of the LPL and transcription factors (PPARγ, C/EBPα). The changes in the protein expression levels of IGFBP7 and adipogenic factors were in accord with the changes observed in the mRNA levels. In conclusion, our results indicate that IGFBP7 plays an important regulatory role in the differentiation of preadipocyte cells.

ALDH1A1 effect on Yan Yellow Cattle preadipocyte differentiation.

Aldehyde dehydrogenase 1A1 (ALDH1A1) is a cytosolic enzyme that mainly catalyzes the oxidation of acetaldehyde into acetic acid and participates in the regulation of differentiation and gene expression in fat cell growth and development. However, the physiological role of ALDH1A1 in the formation of fat cell precursors in the Yan Yellow Cattle is still not clear. Herein, we investigated the specific regulation of the gene encoding for ALDH1A1 during the differentiation process of the adipocyte cells of the Yan Yellow Cattle by interfering or overexpressing the ALDH1A1 gene. As a result, we found that the mRNA expression levels of ALDH1A1 were significantly increased during the formation of progenitor cells. In addition, the expression levels of the Lipoprotein lipase (LPL) and transcription factors (PPARγ, C/EBPα) were also significantly increased. ALDH1A1 gene overexpression and RNA interfering promoted and inhibited respectively the lipid accumulation and triglyceride production in mature adipocytes, and the expression of the LPL and transcription factors (PPARγ, C/EBPα). The changes in the protein expression levels of ALDH1A1 and adipogenic factors were in accord with the changes observed in the mRNA levels. In conclusion, our results indicate that ALDH1A1 plays an important regulatory role in the differentiation of preadipocyte cells.

The effect of Acot2 overexpression or downregulation on the preadipocyte differentiation in Chinese Red Steppe cattle.

The quality and nutritional value of beef is closely linked to its content of intramuscular fat (IMF). The differentiation of preadipocytes and the deposition of lipid droplets in the adipocytes are the key to regulate the IMF content. The differentiation of adipocytes is regulated by a series of transcription factors and genes. Acyl-CoA thioesterase 2 (Acot2) hydrolyzes the acyl-coenzyme A (CoA) into free fatty acids and CoA and has the potential to maintain the free fatty acids and acyl CoA at the cellular level. In this work, we detected the expression of the Acot2 gene during the adipocyte differentiation in Chinese Red Steppe cattle, and then interfered and overexpressed the Acot2 gene in the preadipocytes to explore its regulatory role in the adipocyte differentiation. The results showed that the expression and regulation of Acot2 mainly occurred at the later stage of the adipocyte differentiation. The interference with the Acot2 gene significantly inhibited the lipid droplets accumulation and triglyceride content, while its overexpression significantly promoted both of them. The results of this study show that the Acot2 gene is a positive regulator of the adipocyte differentiation and may become a new target to improve the beef quality.

Effect of ACSL3 Expression Levels on Preadipocyte Differentiation in Chinese Red Steppe Cattle.

Domestic cattle are an important type of livestock, with beef production playing a major role in the agricultural economy. Adipocyte levels and fat content are interrelated, with meat quality being highly dependent on its fat content and distribution. Acyl-CoA synthetases of long-chain (ACSL) fatty acids (FAs) play an integral role in virtually every metabolic pathway in mammalian biochemistry, including complex lipid biosynthesis, protein modification, and ß-oxidation processes. ACSL3 activity is also known to be associated with adipocyte differentiation; however, its biological mechanism of action is currently unclear. Gene expression in subcutaneous preadipocytes isolated from subcutaneous deposits of Chinese Red Steppe cattle has been studied using in vitro cell transfection, real-time polymerase chain reaction and western blot analysis. The lipid and triglyceride contents of lipid droplets have also been measured to verify the levels of gene expression. These combined studies show that ACSL3 is induced during adipocyte differentiation, with its overexpression promoting an increase in the triglyceride content of lipid droplets. Furthermore, mRNA and protein expression levels for adipocyte differentiation marker genes, such as peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), were markedly increased during mature adipocyte cell differentiation. Knockdown of ACSL3 expression using ACSL3 small interfering RNAs (siRNAs) resulted in a decrease in lipid content of cattle adipocytes, providing further evidence that ACSL3 plays a key role in the differentiation process.