Jibin Zhang's ppt for Midwest meeting.pdfMidwest Meeting (2014)
Increasing numbers of fat cells in adipose tissue are attributed to proliferation of preadipocytes or immature adipocytes in the early stages as well as adipogenic differentiation in the later stages of adipogenesis. Although both events are involved in the increase in fat cell numbers, they are contrary to each other in that the former requires cell cycle activity whereas the latter requires cell cycle withdrawal. Therefore, appropriate regulation of cell cycle inhibition is critical to adipogenesis.
To explore the important cell cycle inhibitors and study their expression in adipogenesis, a strategy was adopted that combined the Gene Expression Omnibus (GEO) database on the NCBI website and the results of quantitative real-time PCR (qPCR) analysis of porcine adipose tissue. Three cell
cycle inhibitors—Cyclin G2 (CCNG2), Cyclin-dependent kinase inhibitor 2C (CDKN2C), and Peripheral Myelin Protein (PMP22)—were selected for study because they are relatively highly expressed in adipose tissue compared to muscle, heart, lung, liver, and kidney in humans and mice based on 2 Gene Expression Omnibus Datasets (GDS596 and GDS3142). These genes were found to be more highly expressed in differentiating/differentiated preadipocytes than in undifferentiated preadipocytes in humans and mice as shown by the GDS2366 and GDS2743 datasets, respectively. In addition, the GDS2659 dataset also suggested increasing expression of
the 3 cell cycle inhibitors during differentiation of 3T3L1 cells. Further study with qPCR in Landrace pigs did not confirm the high expression of these genes in adipose tissue compared to other tissues in market-age pigs but confirmed greater expression of these genes in fat cells than in the stromal vascular fraction as well as increasing expression of these genes during in vitro adipogenic differentiation and in vivo development of adipose tissue. Moreover, the expression of all 3 genes was reduced by short-term fasting in market-age pigs but was not restored by short-term refeeding. Based on the analysis of the GEO datasets and qPCR results, we conclude that all 3 cell cycle inhibitors may inhibit adipocyte proliferation but promote adipocyte differentiation and hold a
differentiated state by inducing and maintaining cell cycle inhibition. Therefore, their expression in adipose tissue is positively correlated with age and number of mature fat cells. By regulating expression of these genes, we may be able to control the number of fat cells and, thus, reduce excessive fat tissue in animals and humans.
- cell cycle inhibitors,
- gene expression
Publication DateSpring March 17, 2014
Citation InformationJibin Zhang, Yeunsu Suh, Young Min Choi, Michael E Davis, et al.. "Jibin Zhang's ppt for Midwest meeting.pdf" Midwest Meeting (2014)
Available at: http://works.bepress.com/jibin-zhang/12/