Chronic Rich Glucocorticoids environment affects adipogenic potential of adipocyte precursor cells

ZUBIRÍA GUILLERMINA; ANA ALZAMENDI; GRISELDA MORENO; DANIEL CASTROGIOVANNI; EDUARDO SPINEDI; ANDRÉS GIOVAMBATTISTA

ENDOCRINOLOGY

ENDOCRINE SOC

Año: 2015

0013-7227

Among the fundamental effects of Glucocorticoids (GCs) on adipose tissue (AT) function is their potent stimulatory effect of terminal Adipogenesis; while their effect on early adipocytes differentiation, including competency and determination of adipocyte precursor cells (APCs), is largely unknown. Since these early events contribute to the AT adipogenic potential, we study how chronic exposure to GCs rich environment affects adipogenic activity of APCs from abdominal AT (AAT). We utilized a model of hypercorticosteronemic juvenile and adult (30 and 60 days old) rats induced by treatment with Monosodium Glutamate (MSG). We found that the AAT stromal vascular fraction (SVF) cells showed an increased adipogenic capacity in juvenile MSG rats, including increased cellular lipid content. This effect could be caused by changes in competency or APCs number: we found that MSG rats SVF cells had higher Zfp423, PPARγ2 (competency markers) and also lower Pref-1 and Wnt10b mRNA levels (anti-adipogenic factors), without changes in GCs receptors expression; while the APCs number was unchanged. Overall, this behavior was opposite to the previously described in MSG adult cells. When we analyzed the size of freshly isolated adipocytes we found a right-shift on cell size distribution in both rat ages indicating a hypertrophic process. In agreement with our in vitro data, we found a second population of small cells in MSG adult rats that could be related to adipogenesis activation between both ages. We conclude that high GCs exposure impacts on APCs competency and hence the adipogenic activity, regulating the hyperplasia/hypertrophic balance during AAT expansion.