Department of Clinical Biochemistry and Laboratory Diagnostics, Institute of Medicine, University of Opole, Oleska 48, 45-052 Opole, Poland.
Department of Lifestyle Disorders and Regenerative Medicine, University of Information Technology and Management in Rzeszow, Sucharskiego 2, 35-225 Rzeszow, Poland.
Cytokine. 2020 Feb;126:154930. doi: 10.1016/j.cyto.2019.154930. Epub 2019 Nov 21.
During aging and ischemic and hemorrhagic stroke, elastin molecules are degraded and elastin-derived peptides are released into the brain microenvironment. Val-Gly-Val-Ala-Pro-Gly (VGVAPG) is a repeating hexapeptide in the elastin molecule. It is well documented that the peptide sequence binds with high affinity to elastin-binding protein (EBP) located on the cell surface, thereby transducing a molecular signal into the cell. The aim of our study was to investigate whether EBP, aryl hydrocarbon receptor (Ahr), and peroxisome proliferator-activated receptor gamma (Pparγ) are involved in VGVAPG-stimulated proliferation. Primary astrocytes were maintained in DMEM/F12 medium without phenol red, supplemented with 10 or 1% charcoal/dextran-treated fetal bovine serum (FBS). The cells were exposed to increasing concentrations of VGVAPG peptide, and resazurin reduction was measured. In addition, Glb1, Pparγ, and Ahr genes were silenced. After 48 h of exposure to 10 nM and 1 µM of VGVAPG peptide, the level of estradiol (E) and the expression of Ki67 and S100B proteins were measured. The results showed that at a wide range of concentrations, VGVAPG peptide increased the metabolism of astrocytes depending on the concentration of FBS. After silencing of Glb1, Pparγ, and Ahr genes, VGVAPG peptide did not affect the cell metabolism which suggests the involvement of all the mentioned receptors in its mechanism of action. Interestingly, in the low-FBS medium, the silencing of Glb1 gene did not result in complete inhibition of VGVAPG-stimulated proliferation. On the other hand, in the medium with 10% FBS VGVAPG increased Ki67 expression after Pparγ silencing, whereas in the medium with 1% FBS VGVAPG decreased Ki67 expression. Following the application of Ahr siRNA, VGVAPG peptide decreased the production of E and increased the expression of Ki67 and S100B proteins.
在衰老和缺血性及出血性中风期间，弹性蛋白分子被降解，弹性蛋白衍生肽被释放到脑微环境中。Val-Gly-Val-Ala-Pro-Gly (VGVAPG) 是弹性蛋白分子中的重复六肽。有充分的文献记载表明，该肽序列与位于细胞表面的弹性蛋白结合蛋白 (EBP) 高亲和力结合，从而将分子信号转导到细胞中。我们的研究目的是研究 EBP、芳烃受体 (Ahr) 和过氧化物酶体增殖物激活受体 γ (Pparγ) 是否参与 VGVAPG 刺激的增殖。原代星形胶质细胞在不含酚红的 DMEM/F12 培养基中培养，补充 10%或 1%活性炭/葡聚糖处理的胎牛血清 (FBS)。细胞暴露于递增浓度的 VGVAPG 肽，测量 Resazurin 还原。此外，沉默 Glb1、Pparγ 和 Ahr 基因。暴露于 10 nM 和 1 μM VGVAPG 肽 48 小时后，测量雌二醇 (E) 水平和 Ki67 和 S100B 蛋白的表达。结果表明，在广泛的浓度范围内，VGVAPG 肽增加了星形胶质细胞的代谢，这取决于 FBS 的浓度。沉默 Glb1、Pparγ 和 Ahr 基因后，VGVAPG 肽不影响细胞代谢，这表明所有提到的受体都参与其作用机制。有趣的是，在低 FBS 培养基中，沉默 Glb1 基因并没有导致 VGVAPG 刺激增殖的完全抑制。另一方面，在 10% FBS 培养基中，沉默 Pparγ 后 VGVAPG 增加了 Ki67 的表达，而在 1% FBS 培养基中 VGVAPG 降低了 Ki67 的表达。应用 Ahr siRNA 后，VGVAPG 肽降低了 E 的产生并增加了 Ki67 和 S100B 蛋白的表达。
