CXCL10 regulates pressure overload-induced heart failure

Abstract

Rationale: Heart failure involves tissue inflammation with elevated serum levels of CXCL9 and CXCL10, which are CXCR3 receptor ligands. Both chemokines are expressed by cardiac fibroblasts and myeloid cells in mice subjected to pressure overload induced by transverse aortic constriction (TAC) surgery. Although it is known that CXCR3−/− animals are protected from cardiac remodeling induced by TAC, the role of CXCL10 is unknown. The present study was undertaken to test the hypothesis that CXCL10 is crucial in the cardiac remodeling response to pressure overload induced by TAC in mice. Methods: We subjected wild-type and CXCL10−/− mice to TAC surgery, resulting in 4 experimental groups: WT Sham, WT TAC, CXCL10−/− Sham and CXCL10−/− TAC. WGA was used to analyze the cross-sectional area of cardiomyocytes. To analyze total collagen deposition, PicroSirius Red was used. Immunohistochemistry was performed to measure the number of CD64, CD3g and CD45 positive cells. Echocardiography was used to analyze cardiac function. Results are presented as the mean and standard error of the mean. Comparisons between means were made using two-way variance analysis (ANOVA), as well as Tukey's post hoc test for parametric comparisons, or Kruskal-Wallis and Dunn‘s post hoc test for non-parametric data. Differences with p<0.05 were considered significant. Results: After 1 week, the CXCL10−/− mice showed the same level of cardiac hypertrophy and similar changes in echocardiography parameters, when compared to wild-type mice. However, after 6 weeks, we observed that the CXCL10−/− mice showed an attenuation of heart weight with a reduction in the total collagen deposition compared with wild-type TAC mice. At the cellular level, the genetic deletion of CXCL10 prevented the TAC-induced increase in the cross-sectional area of cardiomyocytes. Moreover, we observed that TAC increased the number of CD3+ T-cells in the heart quantified from stained cross sections of both wild type and CXCL10−/− mice, while no differences were observed for the total number of macrophages. Importantly, echocardiographic changes, including dilation and cardiac dysfunction, induced by pressure overload in wild animals were blunted in CXCL10−/− mice. Corroborating this, the genetic deletion of CXCL10 prevented the increase in lung weight induced by TAC. Conclusion: CXCL10 regulates cardiac hypertrophy and fibrosis induced by pressure overload in mice, as well as the functional changes that characterize heart failure. We are currently unraveling the mechanism through which CXCL10 can accelerate the development of heart failure in response to cardiac pressure overload. Interaction between T cells and macrophages are likely mediating these effects. R01HL155993. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.