Oxidative Stress Inihibited Porcine Preadipocytes Differentiation Is Independent Of Wnt/β-catenin Signaling

Adipose tissue which mostly make up from adipocytes is the biggest energy storage and important endocrine organ playing a more active role in regulating whole-body metabolism and homeostasis. Both excess and deficiency of adipose tissue have cause diseases including obesity and type-2 diabetes and cardiovascular disease. Thus, a better understanding of the molecular mechanisms that control adipose tissue development should improve our knowledge of pathogenesis. Adipocyte differentiation, also known as adipogenesis, is the development of mature adipocytes from multipotent mesenchymal stem cells. This is a highly regulated process controlled by a complex transcriptional cascade and signalling pathway. The peroxisome proliferator-activated receptorγ(PPARγ) and CCAAT/enhancer-binding protein family of transcription factorsα(C/EBPα) are at the center of this network. Recently, the Wnt/beta-catenin signalling pathway has been identified as a regulator of adipogenesis.Oxidative stress (OS) is a general term used to describe the steady state level of oxidative damage in a cell, tissue, or organ, caused by the reactive oxygen species (ROS) . There are several sources by which the reactive oxygen species are generated. Most reactive oxygen species come from the endogenous sources as by-products of normal and essential metabolic reactions. The level of oxidative stress is determined by the balance between the rate at which oxidative damage is induced and the rate at which it is efficiently repaired and removed. Oxidative stress is associated the aging process and disease.Due to pig has the highest fat level and most similar to human physiological characteristics, it's the best animal model to investigate obesity and related metabolic disorders. Therefore, in this study, we adopted porcine preadipocyte which come from dedifferentiation of mature adipocyte, using multiple cellular and molecular technology such as Oil red O stain, Semi-quantity RT-PCR, Western Blot to define the regulation of oxidative stress in adipogenesis and to investigate the mechanism about competitive inhibition between FoxO and Wnt/β-catenin signalling pathway during adipocyte differentiation. The results are as follows:1. The preadipocytes which dedifferentiated from adipocytes possess the ability to redifferentiate to mature fat cell and express marker genes of adipogenesis, Oil red O staining was positive . 2. H2O2, as the inducer of oxidative stress, inhibits preadipocyte proliferation as dose-depended manner. 0.05mmol/L H2O2 didn't work; however, with the increase of H2O2 treatment concentration the density, vitality and growth status of preadipocytes decreased; 0. 5mmol/L H2O2 caused cell a large number of deaths.3. Chose the 0.1mmol/LH2O2 as the best concentration to induce the preadipocte maintaining oxidative stress state.4. Oxidative stress repressed preadipocyte differentiation as time-depended manner. At the very begining (0-3h), it seems didn't work, however, it is obvious repressing differentiation at 24h, lipid accumulation reduced dramatically by using Oil red O stain measured, furthermore, the mRNA and protein level of key adipogenic regulators decreased dramatically.5. There is a competitive inhibition between FoxO and TCF4 associated withβ-catenin. This competitive inhibiton regulated by activation grade of FoxO and content ofβ-catenin in nucleus.6. Oxidative stress Inhibited Porcine preadipocytes differentiation is independent of Wnt/β-catenin Signaling.