Elastin-derived peptide VGVAPG induces redox-associated pro-inflammatory activation and early disease-associated microglia (DAM) molecular profile in a human microglia-neuron in vitro model involving NEU1/TLR4-related signaling.

The elastin-derived hexapeptide Val-Gly-Val-Ala-Pro-Gly (VGVAPG) exhibits well-documented biological activity; however, its role in brain inflammation remains insufficiently characterized. This is an important issue, as VGVAPG levels increase with age and have been implicated in processes contributing to neurodegeneration. The present study aimed to evaluate the ability of aging-related VGVAPG to activate human microglial (HMC3) cells in vitro and to elucidate the underlying molecular mechanisms. Our results demonstrated no cytotoxic effect of VGVAPG. However, further analyses revealed NF-κB nuclear translocation, elevated ROS and •NO production, enhanced iNOS, and accumulation of NLRP3-containing vesicles in the cytoplasm, consistent with the peptide's pro-inflammatory potential. Additionally, activation of stress- and inflammation-related signaling pathways involving p38-MAPK, JNKs, and ERK1/2 was observed, accompanied by upregulation of NFKB1, IL1B, and TNFα mRNA. Using a transwell co-culture model of HMC3 and cholinergic-like neurons (differentiated SH-SY5Y), we observed potential DAMP-associated molecular changes involving HMGB1 and APP. Additionally, NEU1 siRNA-mediated knockdown in HMC3 cells, together with the observed NEU1/TLR4 colocalization, raises the possibility that NEU1 and TLR4 may be involved in the effects induced by VGVAPG. Moreover, VGVAPG induced alterations in early disease-associated microglia (DAM)-related protein profiles, including β2M, ITGAX, and ICAM1. Collectively, these findings identify VGVAPG as a candidate pro-neuroinflammatory matrikine in vitro and provide associative evidence for selected redox, NEU1-, TLR4-related, and early DAM-associated molecular changes. Further investigations employing advanced in vivo and translational models are warranted to validate these observations and to clarify the pathophysiological role of VGVAPG in the progression of neurodegenerative disorders.