The VGVAPG Peptide Regulates the Production of Nitric Oxide Synthases and Reactive Oxygen Species in Mouse Astrocyte Cells In Vitro

Abstract

The products of elastin degradation, namely elastin-derived peptides (EDPs), are detectable in the cerebrospinal fluid of healthy individuals and in patients after ischemic stroke, and their number increases with age. Depending on their concentrations, both nitric oxide (NO) and reactive oxygen species (ROS) take part either in myocardial ischemia reperfusion injury or in neurovascular protection after ischemic stroke. The aim of our study was to determine the impact of VGVAPG peptide on ROS and NO production and expression of endothelial nitric oxide synthase (eNos), inducible nitric oxide synthase (iNos) and neuronal nitric oxide synthase (nNos) in mouse cortical astrocytes in vitro. Primary astrocytes were maintained in DMEM/F12 without phenol red supplemented with 10% fetal bovine serum. The cells were exposed to rising VGVAPG peptide concentrations, and ROS and NO production was measured. After 6 h (for mRNA) and 24 (for the protein) of exposure to 10 nM and 1 µM of the peptide, expression of nNos, iNos and eNos was measured. Moreover, the Glb1 siRNA gene knockdown method and Pioglitazone, a peroxisome proliferator-activated receptor gamma (Pparγ) agonist, were applied. Our study shows that the VGVAPG peptide decreased eNos, iNos and nNos mRNA and protein expression in mouse astrocytes in vitro. The VGVAPG peptide also decreased NO production while increasing ROS production in the cells. Furthermore, silencing of the Glb1 gene reversed all effects caused by the VGVAPG peptide. However, due to the lack of sufficient data explaining the molecular mechanism of action of the VGVAPG peptide in the nervous system, more studies in this area are necessary.

Specific role of N-methyl-D-aspartate (NMDA) receptor in elastin-derived VGVAPG peptide-dependent calcium homeostasis in mouse cortical astrocytes in vitro

“…Our data suggest that the VGVAPG peptide changes the NMDAR expression profile to one similar to the adult profile. Increased expression of GluN2A can promote cell survival and supports our hypothesis postulated in our other papers that the VGVAPG peptide promotes regeneration and the healing process in astrocytes 32,44,50 . However, after Glb1 silencing, the NMDAR expression profile changed to similar to an embryonic one, and could promote cell apoptosis.…”

“…To date, reports concerning ROS production after EDP and/or VGVAPG stimulation are inconsistent. Our previous studies have shown that the VGVAPG peptide increases ROS production in an EBP-dependent manner in mouse primary astrocytes in vitro 32 . Similarly, an increase in ROS production after EDP stimulation has been reported in monocytes, human fibroblasts, and a neuroblastoma (SH-SY5Y) cell line 29,30,33 .…”

“…However, such data suggest that the effects of EDPs are cell and/or tissue dependent. In a previous study, we found that the VGVAPG peptide increases ROS production in an EBP-dependent manner both in mouse astrocytes in vitro 32 and a human neuroblastoma (SH-SY5Y) cell line 33 . It is well known that calcium influx the NMDAR stimulates ROS production 34 .…”

Elastin-derived peptide VGVAPG decreases differentiation of mouse embryo fibroblast (3T3-L1) cells into adipocytes

“…It is well known that EDPs or VGVAPG increase ROS production in different cells such as murine monocytes and astrocytes, human fibroblasts, and neuroblastoma (SH-SY5Y) cells [49][50][51][52][53]. Moreover, ROS are key signalling molecules that play an important role in the progression of inflammatory disorders.…”

Review of the Relationship between Reactive Oxygen Species (ROS) and Elastin-Derived Peptides (EDPs)

“…To date, depending on the model, EDPs have been shown to decrease or increase the cell ROS level [51]. However, the vast majority of studies show that EDPs induce ROS production in human fibroblasts and neuroblastoma (SH-SY5Y) as well as and murine monocytes and astrocytes [9,12,44,45,52]. In addition to the impact on ROS, various authors have shown that EDPs affect the expression and/or activity of antioxidant enzymes.…”