SAT-LB103 Glucose-Dependent Insulinotropic Polypeptide Promotes Proliferation, Inhibits Apoptosis and Modifies Adipogenesis in Human Omental Adipose-Derived Stem Cells
Authors: Chen Xueying , He Xiaoying , Guo Yan , Liu Liehua , Li Hai , Guan Hongyu , Cao Xiaopei , Xiao Haipeng , Li Yanbing 
Published: May 2020

Abstract
Increased visceral fat correlates with a high risk of morbidity and mortality from diabetes and other metabolic diseases. To cope with changes of nutritional status, the adipose tissue undergoes dynamic remodeling, during which adipose derived stem cells (ADSCs) participate through cell proliferation and adipogenic differentiation into mature adipocytes. Besides, beige adipocytes formation from ADSCs, to dissipate energy as heat in mitochondrial via uncoupling protein1 (UCP1) has been proved to improve energy expenditure. Thus, modifying adipose remodeling and promoting beige adipogenesis of ADSCs in visceral fat bring much metabolic benefits. Newly listed LY3298176, an agonist targeted on glucose-dependent insulinotropic polypeptide (GIP) /glucagon-like peptide-1 (GLP-1) receptor, shows outstanding effect of reducing glucose and weight. Due to superior efficacy in dual-target agonist to GLP-1 monotherapy, and the unknown role of GIP in human visceral adipose, we aimed to clarify GIP’s role in undifferentiated ADSCs in vivo. We selected cell model derived from abdominal omental adipose tissue by obtaining ADSCs via primary culture from patients, because of wide-distributed GIP receptors in fat, and the dominant role of abdominal fat in metabolism. Then the cells were allowed to proliferate, or differentiate into adipocytes in the differentiation medium (DM), with or without co-treated with GIP or GIP3-42 (GIP receptor antagonist), followed by subsequently measurement. CCK-8, EdU incorporation, and cell cycle analysis were conducted to assess cellular proliferation. Annexin V FITC/PI stain, TUNEL and cleaved caspase3 detection were performed to evaluate apoptosis. The related signaling pathway was measured by Western blot and the validation was conducted by using pathway inhibitors followed with the above proliferation and apoptosis analysis. Besides, at the early stage of adipogenesis, mitotic clonal expansion (MCE) was reflected by cell cycle detection. Western blot analysis, quantitative real time-PCR (qRT-PCR), and Oil Red O staining were performed to evaluate adipogenesis. We found that GIP facilitated ADSCs viability and DNA synthesis, accelerated cell cycle progress and reduced palmitate-induced apoptosis by promoting phosphorylation of ERK1/2, AKT, PKA and AMPK. We further confirmed that ADSCs after confluence underwent MCE once induced by DM. GIP also modified adipogenesis by accelerating MCE, upregulating core transcription factor (PPARγ and C/EBPα), increasing beige-related markers (UCP1, PGC1α, PRDM16, et al) while suppressing white-related genes (ZFP423 and TLE3). In summary, we illustrated the efficacies of GIP on proliferation, apoptosis and adipogenesis (especially the beige adipocyte formation) of ADSCs, providing evidence of the additional metabolic benefits of GIP/GLP-1 dual-target agonist over GLP-1 agonist monotherapy in vivo.