PATHWAY ANALYSIS OF CHOLESTERYL ESTER ACCUMULATION EFFECT ON INSULIN RESPONSE IN HL-1 CARDIOMYOCYTES

ACTIS DATO, VIRGINIA; REY FEDERICO; CHIABRANDO GA; CESCHIN DANILO

Virtual

Congreso; SAIB - SAMIGE Joint meeting 2021 on line; 2021

SAIB

The cardiovascular disease (CVD) is a multisystem and multicellular pathology frequently associated with increased levels of aggregation-prone small LDL particles. Aggregated LDL (aggLDL) internalization promotes intracellular cholesteryl ester (CE) accumulation and the impairment of insulin response and glucose transporter type 4 (GLUT4) activity in cardiomyocytes.Lipid uptake was associated with cardiac dysfunction and cell death. Nevertheless, the link between CE accumulation and insulin response, cell function and viability in cardiomyocytes is not completely understood yet. The present study was conducted to determine intracellular pathways that are potentially regulated by cholesterol accumulation in heart. For this, we identify gene expression profiles by bulk transcriptome analysis in isolated RNA samples from cardiomyocyte-derived HL-1 cells exposed to aggLDL 100 µg/ml for 8 h and then stimulated or not with insulin 100 nM for 2 h. Considering a fold change (FC)>2 and p<0.01, our results showed that insulin (HI) generated differential expression of 145 genes respect to control condition (MOCK) while aggLDL (HL) generated differential expression of 1145 genes respect to MOCK. In HL-1 cellsexposed to aggLDL and then stimulated with insulin (HIL) were found 1187 genes differentially expressed respect to MOCK. Through enrichment analysis, we found that HI produced gene expression of InsR-PI3K-mTOR signaling, calcium influx and mobilization, cholesterol efflux and cell survival. Moreover, HI generated downregulation of matrix metalloproteinase encoding genes. On the other hand, CE uptake (HL) impaired all these process promoted by HI and upregulated matrixmetalloproteinase encoding genes even in insulin-stimulated HL-1 cells. This evidence was validated by qPCR and mRNA expression analysis of the most important target genes of each network. These impaired pathways corroborate the biological effects found by us and other groups on insulin response and glucose metabolism, contractile activity and cell viability in HL1 cells, allowing to explain the deleterious role of CE at the transcriptomic level. This work provides a novel insight into connected genes regulated by hypercholesterolemia in heart during complex diseases such as CVD.