Depot-Specific Reprogramming of Adipocyte Precursor Cells (APCs) Induced By Glucocorticoid (GC) Exposure

ZUBIRIA GUILLERMINA; FRONTINI Y; REY AMANDA; MORENO G; ALZAMENDI, ANA; SPINEDI, EDUARDO; GIOVAMBATTISTA, ANDRÉS

San Diego

Congreso; Endocrine Society's 97th Annual Meeting.; 2015

Endocrine Society

It is well-known that GC excess favors abdominal adipose tissue (AAT),but not subcutaneous adipose tissue (SCAT) accumulation. However, the effect ofGC pre-exposition on stromal vascular fraction (SVF) cells from both depotsremains unexplored. In the present study we evaluated the impact ofdexamethasone (DXM) on the adipogenic potential of APCs from AAT(retroperitoneal) and SCAT (inguinal) pads. For this aim, SVF cells wereisolated from AAT and SCAT pads (aseptically dissected from adult male S-Drats), and cultured up to reach confluence. Then DXM (0.25-2.5 µM) was added inculture for 48 h (pre-treatment) and the number of cells with adipogenicpotential (defined as CD34+) was determined by flow cytometry. Specificadipocyte competency (PPAR-γ2 and Zfp 423), pro- (MR, GR) and anti- (Wnt10b) adipogenic genemarkers were quantified in cultured cells (qPCR Real Time). Additionally,induction of differentiation was performed and, parameters of differentiatedcells were measured on different differentiation days (Dd): a) adipocytemarkers (PPAR-γ2 and C/EBPα, by qPCR) on Dd 4; and b- intracellular lipid content (Oil-Red O) onDd 10. Our data indicate an increment in PPAR-γ2 gene expression in DXMpre-treated cells (Dd 0, P<0.05) from both AT pads, resulting higher(P<0.05) in AAT than SCAT. Moreover, adipogenic cell population (CD34+)enhanced in DXM-pre-treated AAT cells, but not in those from SCAT.Concordantly, MR and GR gene expression levels were increased byDXM-pre-treatment although only in cultured cells from AAT (P<0.05).Whereas, Wnt10b and Zfp423 gene levels were not affected, regardless of thedepot examined. Differentiated cells pre-treated with DXM displayed increased(P<0.05) mRNA levels (Dd 4) of PPAR-γ2 and C/EBPα, andintracellular lipid content (Dd 10). Interestingly, the later parameters wereeven higher in cells derived from AAT than SCAT (P<0.05). It is concludedthat GC pre-exposition impacts on APCs from AAT and SCAT in a different way, bychanging CD34+ cell population density and competency in AAT, whereas only cellcompetency was modified in SCAT. DXM impacts on SCAT and AAT APCs activities byenhancing their adipogenic capacity, more markedly in AAT than in SCAT APCs.Our study suggests that a GC-rich endogenous environment will furthercontribute to enhance AT mass expansion at the AAT rather than at the SCATlevel, which may help to delay the appearance of AAT cell dysfunction, as seenin the human phenotype of Cushing's Syndrome.