Study of the expression of UDP-Glc:glycoprotein glucosyltransferase (UGGT) isoforms in an ischemia-reperfusion model in rat heart

ROCIO ZUAZO; JAVIER CORIA; PATRICIA BONAZZOLA; SILVIA MIRANDA

Mar del Plata, Buenos Aires

Congreso; Reunion Anual de Sociedades de biociencia; 2019

SAIC.SAFE.SAB.SAP

The first reported isoform of UGGT plays a central role in the endoplasmic reticulum glycoprotein-folding quality control. We have previously reported the existence of a second isoform in the mouse (UGGT2) that showed in vitro biological activity. The aim of this study was to analyze their expression in rat heart and their regulation under an ischemia (I) / reperfusion (R) protocol.Male Wistar rats (2 mo. old) were divided into 4 groups: (I), (R), (Ct) and (C). Rats were anesthetized and heparinized. After loss of reflexes and muscle relaxation, the thorax was opened to quickly excise the heart. The organ was perfused (6 ml min−1 g−1) by the Langerdorff technique with Krebs solution, continuously bubbled with 95% O2 and 5% CO2, at 37⁰C and electrically stimulated (5V, 5ms) at 3 Hz while the left intraventricular pressure (LVP) and calorimetric response were monitored. After 60 min of equilibration, perfusion was stopped during 30min (I group) and re-perfused for 45min (R group). Ct hearts were perfused during 75min, while hearts before ?I? stimulus were considered the C group. Expression of UGGTs was investigated in heart sections by immunohistochemistry (IHC) and in left ventricles by Dot and Western Blot (D/WB), n=3/group. Protein expression was determined by densitometry of the blot bands by ImageJ 1.42q software.Our results showed that both isoforms are expressed in (C) hearts. IHC studies showed that UGGT1 was upregulated while UGGT2 diminished in I and R groups. D/WB studies confirmed that LV from I group expressed the UGGT1´s highest expression followed by (R), I vs Ct: p