Dysfunctional EAT thickness may promote maladaptive heart remodeling in CVD patients through the ST2-IL33 system, directly related to EPAC protein expression

Figures

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  Figure 1. EAT thickness directly correlates with ST2 expression and inversely with IL-33. (a) End-diastolic (a1-a2) and end-systolic (b1-b2) echocardiographic frames, showing EAT thickness (red arrows). (b) Correlation results among EAT measurement and both ST2 molecular expression (r = 0.54, p < 0.0001) and IL-33 (Spearmann r = −0.50; p < 0.01) suggesting a potential involvement of fat body increase in ST2/IL-33 regulation.

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  Figure 2. ST2 and IL-33 cardiac stretch mediators expression, production and immunolocalization in EAT. Under biomechanical stretchING the main cytokines involved in compensatory remodeling in the heart are ST2 and IL-33. We measured their expression, protein production and total circulating levels in EAT biospies from CVD patients. (a) EAT presents significantly higher expression of IL-33 gene than IL1RL1 (ST2), and ST2 and IL-33 expression is inversely correlated. sST2 total circulating level is higher than Il-33 circulating protein. (b) Western blot shows that EAT is a source of the ST2 cardiac stretch mediator and IL-33 cardioprotective proteins. (c) Representative images of EAT biopsies with immunoreaction for ST2 and IL-33 positive cells in separate panels (panels II with magnification). Both ST2 immunoreactivity and IL-33 are present in EAT biopsies specially those close to endothelial vessels.

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  Figure 3. Adipose tissue size regulators EPAC1 and EPAC2 are express in EAT and EPAC2 directly correlates with IL1RL1 expression. EPAC proteins, the main effectors of cAMP as controllers of adipose tissue size and metabolism, are expressed by EAT from CVD patients. (a) EPAC1 isoform is significantly overexpressed compared to the EPAC2 isoform in EAT cells, as shown by microarray results (p < 0.0001) but the total protein production, analyzed by Western blot and quantified normalizing the data using stain-free gels, indicated higher expression of EPAC2 protein than EPAC1, although the difference was not significant. (b) Correlation analysis between the expression of EPAC1 and EPAC2 adipose tissue size controllers and the ST2 cardiac stretch mediator in dysfunctional EAT biopsies. Only the EPAC2 isoform directly correlates with the ST2 gene level (Spearman r = 0.74, p < 0.0001). No differences were found between the EPAC1 and ST2 gene.