Fig. 5: IRE1α ablation in ECs impacts islet transcriptomes with enhanced islet Thrombospondin 1 expression in HFD-fed mice.

a–d Global gene expression analysis by RNA-seq using total RNA extracts from isolated primary islets of Ern1^fl/fl and Ern1^EC-KO mice after 16 weeks of HFD feeding (n = 3 per group). a Gene ontology (GO) biological process (BP) analysis of 573 genes (average FPKM > 1; |log₂ fold-change (FC) | > 0.5) whose expression was significantly different as a result of IRE1α deficiency in ECs. b Volcano plot depicting the log₂(FC) values (Ern1^EC-KO versus Ern1^fl/fl) versus -log₁₀(P-values) for genes (FPKM > 1) from the RNA-seq analysis of islets. Highlighted are up-regulated (red) or down-regulated (blue) genes ( | log₂(FC) | > 0.5; P Value < 0.01) resulting from endothelial IRE1α deficiency. c List of top-ranked genes whose expression was significantly upregulated or downregulated in islets with EC IRE1α deficiency (FPKM > 1; |log₂(FC) | > 0.5; P Value < 0.01). d Heat maps of 7 genes (average FPKM > 1; |log₂(FC) | > 0.5; P Value < 0.01) involved in regulation of endothelial proliferation, which were differentially expressed in islets from HFD-fed Ern1^EC-KO mice versus their Ern1^fl/fl counterparts (n = 3 mice per group). e, f Primary islets isolated from Ern1^fl/fl and Ern1^EC-KO mice after 16 weeks of HFD feeding. e Quantitative RT-PCR analysis of the mRNA abundance of islet Thbs1 (n = 7 per group) and Egfl7 (Ern1^fl/fl, n = 6; Ern1^EC-KO, n = 7). f Immunoblot analysis of islet TSP1 protein levels (Ern1^fl/fl, n = 5; Ern1^EC-KO, n = 6). α-Tubulin was used as a loading control. Data are shown as mean ± SEM by unpaired two-tailed Student’s t-test (e, f).