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Loss of AMIGO2 causes dramatic damage to cardiac preservation after ischemic injury.

ABSTRACT

Recent studies have identified amphoterin-induced gene and open reading frame (AMIGO) 2. The role of AMIGO2 in tumour research is well-studied, but its role in ischemic heart diseases is seldom reported. In the present study, the role of AMIGO2 in myocardial infarction is under investigation for the first time. For in vitro studies, cardiomyocytes (CMs) and endothelial cells (ECs) were isolated from both AMIGO2 knockout (KO) and WT mice. The apoptosis of CMs was tested after 48 h of ischemic stimulation. A proliferation test was implemented after 7 days of normoxic incubation and tube formation on ECs. For in vivo studies, the MI model was built in mice hearts. Echocardiographic evaluation was performed at 3 days and 28 days post-MI, while the hemodynamics test was performed at 28 days post-MI. The histological results of the apoptosis, proliferation, angiogenesis and infarct zone assessments were determined using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) assay, Ki67 staining, α-SMA/CD31 immunostain and the Masson-Trichrome method, respectively. The expression changes of the Akt pathway and related proteins were confirmed using both quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. The present results demonstrated that AMIGO2 deficiency caused more CMs suffering apoptosis, lower proliferation and less angiogenesis in vitro and in vivo. Weaker cardiac function and larger scar formation were detected in AMIGO2 KO mice, and increased expression of active-caspase-3 and decreased expression of PDK1, p-Akt, Bcl-2/Bax and VEGF occurred. Herein the findings indicate that AMIGO2 deficiency plays an attenuated cardio-protective role in ischemic heart disease via inactivation of the PDK1/Pten/Akt pathway.