Project description:Background Chronic sustained pressure overload induces cardiac remodeling, which often leads to heart failure. Cardiac macrophages (cMacs) are heterogeneous cell populations, and their elimination has been shown to exacerbate pressure overload-induced heart failure. CD163, a macrophage-specific scavenger receptor expressed in a subset of cMacs, has been linked to cardiovascular events through its serum soluble form. This study aimed to elucidate the functional role of the CD163+ cMacs subset in pressure overload-induced heart failure. Methods Transverse aortic constriction (TAC) was performed on wild-type and CD163-deficient (Cd163-/-) mice to investigate the role of CD163 in pressure overload-induced cardiac remodeling and heart failure. Echocardiography was used to assess heart structure and function. Transcriptomic analysis and transmission electron microscopy were employed to observe mitochondrial structure in cardiomyocytes. Flow cytometry was used to quantify cMacs and cytokine-expressing cMacs in the heart. Additionally, serum samples from hypertensive patients with and without heart failure were analyzed to explore the relationship between CD163 and heart failure. Results TAC-induced left ventricular systolic dysfunction, including reduced ejection fraction and fractional shortening, was significantly aggravated in Cd163-/- mice post-surgery. Genes differentially expressed due to CD163 deficiency were enriched in pathways related to mitochondrial bioenergetics and homeostasis. Transmission electron microscopy revealed an increase in dysfunctional mitochondria in cardiomyocytes of Cd163-/- mice post-TAC. Additionally, decreased serum interleukin (IL)-10 levels and reduced IL-10 expression in cMacs were observed in Cd163-/- mice post-TAC. IL-10 supplementation significantly reversed TAC-induced reductions in left ventricular systolic function and improved mitochondrial bioenergetics and homeostasis in Cd163-/- mice. Conclusions The protective functions of CD163 in cMacs are associated with IL-10 expression during pressure overload-induced heart failure.
Project description:Recent high-throughput approaches have revealed a vast number of transcripts with unknown functions. Many of these transcripts are long noncoding RNAs (lncRNAs), and intergenic region-derived lncRNAs are classified as long intergenic noncoding RNAs (lincRNAs). Although Myosin heavy chain 6 (Myh6) encoding primary contractile protein is down-regulated in stressed hearts, the underlying mechanisms are not fully clarified especially in terms of lincRNAs. Here, we screen upregulated lincRNAs in pressure overloaded hearts and identify a muscle-abundant lincRNA termed Lionheart. Compared with controls, deletion of the Lionheart in mice leads to decreased systolic function and a reduction in MYH6 protein levels following pressure overload. We reveal decreased MYH6 results from an interaction between Lionheart and Purine-rich element-binding protein A after pressure overload. Furthermore, human LIONHEART levels in left ventricular biopsy specimens positively correlate with cardiac systolic function. Our results demonstrate Lionheart plays a pivotal role in cardiac remodeling via regulation of MYH6.
Project description:Cardiac macrophages (cMacs) elimination exacerbates pressure overload-induced heart failure. However, the role of functionally distinct subsets of cMacs in heart failure remains largely unknown. CD163, a macrophage-specific scavenger receptor expressed in a subset of cMacs, has been associated with cardiovascular events through its circulating soluble form. This study aimed to elucidate the functional role of the CD163+ cMacs subset in pressure overload-induced heart failure. Transverse aortic constriction (TAC) was used to induce pressure overload. TAC-induced left ventricular systolic dysfunction, characterized by reduced ejection fraction and fractional shortening, was significantly aggravated in Cd163−/− mice post-surgery. Genes differentially expressed due to CD163 deficiency were enriched in pathways related to mitochondrial bioenergetics and homeostasis. Transmission electron microscopy revealed an increase in dysfunctional mitochondria in cardiomyocytes of Cd163−/− mice post-TAC. Additionally, decreased serum interleukin (IL)-10 levels and reduced IL-10 expression in cMacs were observed in Cd163−/− mice post-TAC. IL-10 supplementation significantly reversed TAC-induced reductions in left ventricular systolic function in Cd163−/− mice and improved mitochondrial functions in cardiomyocytes. Furthermore, decreased IL-10 levels and increased soluble CD163 were identified as risk factors for heart failure in hypertensive patients. Thus, CD163 in cMacs attenuates pressure overload-induced left ventricular systolic dysfunction through IL-10.
Project description:To look at the affect of talins in cardiac fibroblasts (CF), we subjected Tln2-null and Tln2-null; Tln1-specific CF knockout mice to AngII stimulation for 8 weeks to induce pressure overload injury. We found that Tln2-null; Tln1-specific CF knockout mice had increaed cardiomyocyte hypertrophy and systolic blood pressure, with not change in intersitial fibrosis.