AMP kinase activation by Omega-3 polyunsaturated fatty acid protects the retina against ischemic insult: An in vitro and in vivo study

Author(s)

Datilo, Marcella N. ; Formigari, Guilherme P. ; Lopes de Faria, Jose B. ; Lopes de Faria, Jacqueline M.

• Document type: Journal article
• Source: EXPERIMENTAL EYE RESEARCH; v. 226, p. 10-pg., 2022-12-18.

Abstract

Purpose: To investigate the possible beneficial effects of omega-3 polyunsaturated fatty acids (omega 3-PUFAs) in ischemic retinal angiogenesis and whether AMP-activated protein kinase (AMPK) is involved.Methods: Human retinal microvascular endothelial cells (hRMECs) were exposed to dimethyloxalylglycine (DMOG), a hypoxia-inducible factor hydroxylase inhibitor, in the presence or absence of docosahexaenoic acid (DHA) and small interfering RNA (siRNA) for AMPK alpha for 24 h. Ischemic factors, endothelial mesenchymal transition marker, endothelial barrier integrity, cell migration, and tube formation were evaluated. Neonatal AMPK alpha 2-/-and control wild-type (WT) mice were submitted to an oxygen-induced retinopathy (OIR) protocol; their nursing mother mice were either fed omega 3-PUFAs or not. In the end, ischemic markers and endothelial cell proliferation were evaluated in neonatal mouse retinal tissue through immunohistochemical or immunofluo-rescent assays among all studied groups.Results: Cells exposed to DMOG displayed increased expressions of hypoxic and endothelial mesenchymal transition (vimentin) markers and barrier disarrangement of Zonula Occludens-1 compared to the control, accompanied by increased cellular migration and tube formation (p < 0.05). AMPK activity was significantly decreased. Supplementation with DHA restored the mentioned alterations compared to DMOG (p<0.05). In siRNAAMPK alpha-treated cells, the beneficial effects observed with DHA were abolished. DHA upregulated G-protein receptor-120 (GPR120), which promptly increased intracellular levels of calcium (p <= 0.001), which conse-quently increased Calcium/calmodulin-dependent protein kinase kinase beta expression (CaMKK beta) thus phos-phorylating AMPKThr172. AMPK alpha 2-/-and wild-type (WT) OIR mice exhibited similar retinal ischemic changes, and the oral supplementation with omega 3-PUFA efficiently prevented the noticed ischemic alterations only in WT mice, suggesting that AMPK alpha 2 is pivotal in the protective effects of omega 3-PUFA.Conclusions: omega 3-PUFAs protect the retina from the effects of ischemic conditions, and this effect occurs via the GPR120-CaMKK beta-AMPK axis. A better understanding of this mechanism might improve the control of patho-logical angiogenesis in retinal ischemic diseases. (AU)

• FAPESP's process: 14/22687-0 - Contribution of AMPK pathway to renal fibrosis and pathogenesis of diabetic nephropathy and retinopathy
• Grantee: Jose Butori Lopes de Faria
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 18/07398-3 - Involvement of AMPK in the retina of AMPK Knockout mice in experimental models of Diabetes and Proliferative Ischemic Retinopathy: in vivo and in vitro
• Grantee: Marcella Neves Dátilo
• Support Opportunities: Scholarships in Brazil - Doctorate