TY - JOUR TI - Orexin-a exerts equivocal role in atherosclerosis process depending on the duration of exposure: In vitro study AU - Ansari, N.N. AU - Spentza, F. AU - Dimitriadis, G.K. AU - Daskalopoulou, A. AU - Karapanagioti, A. AU - Siasos, G. AU - Lianidou, E. AU - Papavassiliou, A.G. AU - Kassi, E. AU - Randeva, H.S. JO - Nutrient Cycling in Agroecosystems PY - 2020 VL - 12 TODO - 1 SP - null PB - MDPI AG SN - 1385-1314 TODO - 10.3390/nu12010053 TODO - gelatin; gelatinase A; gelatinase B; heme oxygenase 1; matrix metalloproteinase; messenger RNA; monocyte chemotactic protein 1; orexin A; synaptophysin; tissue inhibitor of metalloproteinase 1; tissue inhibitor of metalloproteinase 2; transcription factor RelA, aortic endothelial cell; Article; atherogenesis; atherosclerosis; cell culture; cell proliferation assay; cell signaling assay; cell viability assay; controlled study; drug exposure; endothelium cell; enzyme activity; enzyme linked immunosorbent assay; feeding behavior; homeostasis; human; human cell; in vitro study; incubation time; MTS assay; polymerase chain reaction; protein expression; protein phosphorylation; real time polymerase chain reaction; signal transduction; treatment duration; Western blotting; zymography TODO - Orexin-A is a peptide hormone that plays a crucial role in feeding regulation and energy homeostasis. Diurnal intermittent fasting (DIF) has been found to increase orexin-A plasma levels during fasting hours, while Ramadan fasting which resembles DIF, has led to beneficial effects on endothelial function. Herein, we aimed to investigate the effects of orexin-A on the expression of molecules involved in the atherogenesis process: Monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and tissue inhibitor of metalloproteinase-1 and 2 (TIMP-1 and TIMP-2), in human aortic endothelial cells (HAECs). HAECs were incubated with orexin-A at concentrations of 40 ng/mL, 200 ng/mL and 400 ng/mL for 6, 12 and 24 h. The mRNA levels of MCP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 and orexin-1 receptor were measured by real-time qPCR. We also evaluated the MMP-2, p38, phospho-p38, NF-κB/p65 as well as TIMP-1 protein levels by Western blot and ELISA, respectively. MMP-2 activity was measured by gelatin zymography. Short-term 6-h incubation of HAECs with orexin-A at a high concentration (400 ng/mL) decreased MCP-1, MMP-2 expression, MMP-2/TIMP-1 ratio (p < 0.05), and MMP-2 activity, while incubation for 24 h increased MCP-1, MMP-2 expression (p < 0.05), MMP-2/TIMP-1 and MMP-2/TIMP-2 ratio (p < 0.01 and p < 0.05, respectively) as well as MMP-2 activity. The dual effects of orexin-A are mediated, at least in part, via regulation of p38 and NF-κB pathway. Orexin-A may have an equivocal role in atherosclerosis process with its effects depending on the duration of exposure. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. ER -