A Comprehensive miRNome Analysis of Macrophages Isolated from db/db Mice and Selected miRNAs Involved in Metabolic Syndrome-Associated Cardiac Remodeling

Abstract

Cardiac macrophages are known from various activities, therefore we presume that microRNAs (miRNAs) produced or released by macrophages in cardiac tissue have impact on myocardial remodeling in individuals with metabolic syndrome (MetS). We aim to assess the cardiac macrophage miRNA profile by selecting those miRNA molecules that potentially exhibit regulatory functions in MetS-related cardiac remodeling. Cardiac tissue macrophages from control and db/db mice (an animal model of MetS) were counted and sorted with flow cytometry, which yielded two populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Total RNA was then isolated, and miRNA expression profiles were evaluated with Next Generation Sequencing. We successfully sequenced 1400 miRNAs in both macrophage populations: CD45+CD11b+CD64+Ly6Chi and CD45+CD11b+CD64+Ly6Clow. Among the 1400 miRNAs, about 150 showed different expression levels in control and db/db mice and between these two subpopulations. At least 15 miRNAs are possibly associated with MetS pathology in cardiac tissue due to direct or indirect regulation of the expression of miRNAs for proteins involved in angiogenesis, fibrosis, or inflammation. In this paper, for the first time we describe the miRNA transcription profile in two distinct macrophage populations in MetS-affected cardiac tissue. Although the results are preliminary, the presented data provide a foundation for further studies on intercellular cross-talk/molecular mechanism(s) involved in the regulation of MetS-related cardiac remodeling.

Multiple roles of cardiac macrophages in heart homeostasis and failure

“…However, detailed mechanisms are still not completely understood. Multiple pathways leading to HF seem to be triggered by macrophages, depending on the phenotypic character of these cells defined by their secretome, miRNome [72], and genetic (mRNA) profile. Nevertheless, it is known that the role of macrophages in hypertension, obesity, diabetes, renal dysfunction, which are risk factors leading to HF, is crucial [69,70].…”

miR-31-5p-Modified RAW 264.7 Macrophages Affect Profibrotic Phenotype of Lymphatic Endothelial Cells In Vitro

“…In our previous studies we focused on myocardial remodeling, which can be caused by MetS and leads to diabetic cardiomyopathy and heart failure. Pathological changes within the heart include remodeling of blood and lymphatic vessels, perivascular and interstitial fibrosis, as well as mild inflammation [ 7 , 17 ]. The molecular mechanisms underlying these morphological changes are largely unknown and orchestrated by a great number of resident and infiltrating cells, including macrophages [ 19 ].…”

“…In our previously published paper, we show that macrophage populations isolated from the myocardium of diabetic db/db mouse exhibit different profile of miRNA expression compared to control [ 17 ]. At least some of the affected miRNAs can be involved in angiogenesis, lymphangiogenesis, and fibrosis, and thus their altered levels may be responsible for the morphological changes of the myocardium.…”

“…Moreover, miRNAs can act differently, depending on the tissue microenvironment and cell type. In our previous paper we demonstrate that miR-31-5p is upregulated in cardiac macrophages isolated from db/db mouse hearts [ 17 ]. Db/db mice are used as an animal model of metabolic syndrome (MetS) and exhibit symptoms of heart failure [ 18 ].…”

“…Db/db mice are used as an animal model of metabolic syndrome (MetS) and exhibit symptoms of heart failure [ 18 ]. The myocardium of db/db mice shows a reduced number of lymphatic and blood microvessels, increased fibrosis, and mild inflammation [ 17 ]. The molecular mechanisms underlying these changes are not well understood.…”