Department of Lifestyle Disorders and Regenerative Medicine, University of Information Technology and Management in Rzeszow, Sucharskiego 2, 35-225, Rzeszow, Poland.
Department of Management, Faculty of Administration and Social Sciences, University of Information Technology and Management in Rzeszow, Sucharskiego 2, 35-225, Rzeszow, Poland.
Neurochem Res. 2020 Feb;45(2):385-394. doi: 10.1007/s11064-019-02920-3. Epub 2019 Nov 27.
Astrocytes play many distinct roles in the nervous system providing structural support for neurons and maintaining blood-brain barrier integrity. Steroid hormones exhibit a broad spectrum of actions in the central and peripheral nervous system, acting as trophic factors affecting cell differentiation and synaptic plasticity. In steroidogenesis, astrocytes play a key role by producing cholesterol, progesterone (P), testosterone (T), and estradiol (E). Currently there are only few studies which show that the Gly-Val-Ala-Pro-Gly (VGVAPG) peptide may affect the metabolism of astrocytes. Therefore, due to the role of neurosteroids, it is necessary to determine whether VGVAPG affects the level of E, P, and T in astrocytes. Primary mouse astrocytes were maintained in DMEM/F12 without phenol red, and supplemented with 10% charcoal/dextran-treated fetal bovine serum. Cells were exposed to 10 nM and 1 µM VGVAPG peptide and co-treated with cSrc kinase inhibitor I. After cell stimulation, we measured the Ki67 protein level and the production and secretion of P, T, and E. Our report presents the novel finding that the VGVAPG peptide affects the production and secretion of neurosteroids in astrocytes in vitro. The VGVAPG peptide increases the production of P; however, at the same time, it decreases the secretion of P by astrocytes. On the other hand, it stimulates the production and secretion of T. Interestingly, the production of E did not change in any studied time interval. The expression of Ki67 protein increased after 48 h of exposition to the VGVAPG peptide. The cSrc kinase inhibitor I prevented most of the effects of VGVAPG peptide. Therefore, we postulate that T and cSrc kinase may be responsible for increasing astrocyte proliferation.
星形胶质细胞在神经系统中发挥许多不同的作用，为神经元提供结构支持，并维持血脑屏障的完整性。甾体激素在中枢和外周神经系统中表现出广泛的作用，作为营养因子影响细胞分化和突触可塑性。在类固醇生成中，星形胶质细胞通过产生胆固醇、孕酮（P）、睾丸酮（T）和雌二醇（E）发挥关键作用。目前只有少数研究表明 Gly-Val-Ala-Pro-Gly（VGVAPG）肽可能影响星形胶质细胞的代谢。因此，由于神经甾体的作用，有必要确定 VGVAPG 是否影响星形胶质细胞中 E、P 和 T 的水平。原代小鼠星形胶质细胞在不含酚红的 DMEM/F12 中培养，并补充 10%活性炭/葡聚糖处理的胎牛血清。细胞暴露于 10 nM 和 1 µM VGVAPG 肽，并与 cSrc 激酶抑制剂 I 共同处理。细胞刺激后，我们测量了 Ki67 蛋白水平以及 P、T 和 E 的产生和分泌。我们的报告提出了一个新的发现，即 VGVAPG 肽在体外影响星形胶质细胞中神经甾体的产生和分泌。VGVAPG 肽增加了 P 的产生；然而，同时，它减少了 P 的分泌。另一方面，它刺激了 T 的产生和分泌。有趣的是，E 的产生在任何研究的时间间隔内都没有变化。VGVAPG 肽暴露 48 小时后 Ki67 蛋白的表达增加。cSrc 激酶抑制剂 I 阻止了 VGVAPG 肽的大部分作用。因此，我们假设 T 和 cSrc 激酶可能负责增加星形胶质细胞增殖。
