Establishment and characterization of a RSUME knockout model under normoxic and hypoxic conditions

NICOLAS CIANCIO DEL GIUDICE; DAVID GONILSKI PACIN; CAROL FAGUNDEZ; CAROLINA CÁRDENAS-FIGUEROA; MARÍA B. ELGUERO; MARIANA FUERTES; EDUARDO ARZ

Mar del plata

Congreso; REUNIÓN CONJUNTA SAIC SAI&FAIC SAFIS 2022; 2022

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC)

Rwdd3 o RSUME (RWD-containing SUMOylation Enhancer), is aprotein whose gene was cloned in our laboratory. In previous workswe found a regulatory role for RSUME on the HIF-VHL pathway andalso on its main related process, angiogenesis, in kidney cancer.Recent studies reveal that RSUME is connected with cardiac tissueresponse to ischemia and stroke. Given the complexity of these pathologies,a whole-organism approach is needed to study the roleof RSUME in its target tissues. Taking this into account the aim ofthis work is to study the role of RSUME in the response to normoxiaand hypoxia in a RSUME-knockout (KO)-mouse model. KO mice forRSUME (Tm1d) were generated in our laboratory from the geneticallyengineered mouse model Rwdd3tm1a. WT and TM1D micewere exposed to normoxia or hypoxia during 3 or 7 days. To studyfunctional alterations induced by hypoxia, cardiac hemodynamic parameterssuch as Right ventricular pressure, Fulton index and Hematocritwere measured and key proteins for each tissue were analyzed.KO model for Rwdd3 gene was successfully developed andthe absence of RSUME expression was validated. We observed adecrease in cardiac connexin43 (CX43) by Western blot (FC=0.714p= 0.0381) and RT-qPCR in Tm1d mice (FC=0.4928 p=0.008) whilethe levels of Potassium channel KCNH2 expression measured byRT-qPCR were higher in Tm1d (FC=1.756 p=0.0041). We also foundthat heart VHL levels were lower by RT-qPCR in Tm1d (FC=0.7397p=0.0037). Regarding cardiac parameters electrocardiogram (ECG)changes were found in KO mice for Rwdd3. Hypoxia modified hemodynamicparameters showed no differences between WT and Tm1d.These experimental results demonstrate that RSUME modulateskey molecules linked with heart electrophysiology and HIF pathways.