Laboratorio de Neuroendocrinología, Instituto Multidisciplinario de Biología Celular (IMBICE, CICPBA-CONICET-UNLP), Calle 526 10 y 11, La Plata 1900, Argentina.
Laboratorio de Integración de Señales Celulares, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET-UNCUYO), Mendoza, Argentina.
Life Sci. 2020 Nov 15;261:118363. doi: 10.1016/j.lfs.2020.118363. Epub 2020 Aug 28.
Dexamethasone (DXM) is a synthetic glucocorticoid whose effects in early and terminal adipogenesis have been addressed. In this study, we evaluated if DXM affects adipocyte precursor cells (APCs), priming them for further adipogenic differentiation. For this purpose, we analyzed APCs number and competency after DXM treatment.
Adult male rats were injected for 2 or 7 days with either DXM (30 μg/kg of weight, sc.) or vehicle. Stromal vascular fraction (SVF) cells from retroperitoneal adipose tissue (RPAT) were isolated to quantify APCs by flow cytometry (CD34/CD45/CD31). Also, expression of competency markers (PPARγ2 and Zfp423) was assessed. Additionally, SVF cells from control rats were incubated with DXM (0.25 μM) alone or combined with a mineralocorticoid receptor (MR) antagonist (Spironolactone 10 μM) and/or a glucocorticoid receptor (GR) antagonist (RU486 1 μM) to assess APCs competency and adipocyte differentiation.
APCs from 2 days DXM-treated rats showed increased expression of PPARγ2 and Zfp423 (competency markers), but did not affect APCs percentage by FACS analysis (CD34/CD45/CD31). Additionally, we found that DXM treatment in SVF also increased APCs competency in vitro, predisposing APCs to further adipocyte differentiation. These effects on APCs were abrogated only when both, MR and GR, were blocked.
Overall, our results suggest that DXM primes APCs for differentiation mainly by enhancing Zfp423 and PPARγ2 expressions. Also, we showed that the inhibition of MR and GR was necessary for the complete abolishment of DXM effects.
地塞米松（DXM）是一种合成的糖皮质激素，其在早期和终末期脂肪生成中的作用已得到研究。在这项研究中，我们评估了 DXM 是否会影响脂肪细胞前体细胞（APCs），使它们为进一步的脂肪生成分化做好准备。为此，我们分析了 DXM 处理后 APCs 的数量和能力。
成年雄性大鼠连续 2 天或 7 天接受 DXM（30μg/kg 体重，sc.）或载体注射。从腹膜后脂肪组织（RPAT）分离基质血管部分（SVF）细胞，通过流式细胞术（CD34/CD45/CD31）来定量 APCs。还评估了能力标志物（PPARγ2 和 Zfp423）的表达。此外，将来自对照大鼠的 SVF 细胞与 DXM（0.25μM）单独孵育，或与盐皮质激素受体（MR）拮抗剂（螺内酯 10μM）和/或糖皮质激素受体（GR）拮抗剂（RU486 1μM）联合孵育，以评估 APCs 的能力和脂肪细胞分化。
2 天 DXM 处理的大鼠的 APCs 表现出 PPARγ2 和 Zfp423（能力标志物）的表达增加，但通过 FACS 分析（CD34/CD45/CD31）并未影响 APCs 的百分比。此外，我们发现 DXM 处理 SVF 也增加了 APCs 在体外的能力，使 APCs 更容易进一步分化为脂肪细胞。只有当同时阻断 MR 和 GR 时，这些对 APCs 的影响才会被消除。
总体而言，我们的结果表明，DXM 主要通过增强 Zfp423 和 PPARγ2 的表达来启动 APCs 的分化。此外，我们表明，MR 和 GR 的抑制对于完全消除 DXM 的作用是必要的。
