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MicroRNA let-7c regulates macrophage polarization.

ABSTRACT: Macrophages demonstrate a high level of plasticity, with the ability to undergo dynamic transition between M1 and M2 polarized phenotypes. The role of microRNAs (miRNAs) in regulating macrophage polarization has been largely undefined. In this study, we found that miRNA let-7c is expressed at a higher level in M-BMM (M2 macrophages) than in GM-BMM (M1 macrophages). let-7c levels are also greater in alveolar macrophages from fibrotic lungs as compared with those from normal lungs. let-7c expression was decreased when M-BMM converted to GM-BMM, whereas it increased when GM-BMM converted to M-BMM. LPS stimulation reduced let-7c expression in M-BMM. We found that overexpression of let-7c in GM-BMM diminished M1 phenotype expression while promoting polarization to the M2 phenotype. In contrast, knockdown of let-7c in M-BMM promoted M1 polarization and diminished M2 phenotype expression. We found that let-7c targets C/EBP-?, a transcriptional factor that plays an important role in inflammatory response. Furthermore, we found that let-7c regulates bactericidal and phagocytic activities of macrophages, two functional phenotypes implicated in macrophage polarization. Our data suggest that the miRNA let-7c plays an important role in regulating macrophage polarization.

SUBMITTER: Banerjee S

PROVIDER: S-EPMC3679284 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature

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MicroRNA let-7c regulates macrophage polarization.

Banerjee Sami S Xie Na N Cui Huachun H Tan Zheng Z Yang Shanzhong S Icyuz Mert M Abraham Edward E Liu Gang G

Journal of immunology (Baltimore, Md. : 1950) 20130510 12

Macrophages demonstrate a high level of plasticity, with the ability to undergo dynamic transition between M1 and M2 polarized phenotypes. The role of microRNAs (miRNAs) in regulating macrophage polarization has been largely undefined. In this study, we found that miRNA let-7c is expressed at a higher level in M-BMM (M2 macrophages) than in GM-BMM (M1 macrophages). let-7c levels are also greater in alveolar macrophages from fibrotic lungs as compared with those from normal lungs. let-7c expressi ...[more]

PMID: 23667114

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Project description:OBJECTIVE:This study investigated the role of microRNAs generated from adipose tissue macrophages (ATMs) during adipose tissue remodeling induced by pharmacological and nutritional stimuli. METHODS:Macrophage-specific Dicer knockout (KO) mice were used to determine the roles of microRNA generated in macrophages in adipose tissue remodeling induced by the β3-adrenergic receptor agonist CL316,243 (CL). RNA-seq was performed to characterize microRNA and mRNA expression profiles in isolated macrophages and PDGFRα+ adipocyte stem cells (ASCs). The role of miR-10a-5p was further investigated in cell culture, and in adipose tissue remodeling induced by CL treatment and high fat feeding. RESULTS:Macrophage-specific deletion of Dicer elevated pro-inflammatory gene expression and prevented CL-induced de novo beige adipogenesis in gonadal white adipose tissue (gWAT). Co-culture of ASCs with ATMs of wild type mice promoted brown adipocyte gene expression upon differentiation, but co-culture with ATMs of Dicer KO mice did not. Bioinformatic analysis of RNA expression profiles identified miR-10a-5p as a potential regulator of inflammation and differentiation in ATMs and ASCs, respectively. CL treatment increased levels of miR-10a-5p in ATMs and ASCs in gWAT. Interestingly, CL treatment elevated levels of pre-mir-10a in ATMs but not in ASCs, suggesting possible transfer from ATMs to ASCs. Elevating miR-10a-5p levels inhibited proinflammatory gene expression in cultured RAW 264.7 macrophages and promoted the differentiation of C3H10T1/2 cells into brown adipocytes. Furthermore, treatment with a miR-10a-5p mimic in vivo rescued CL-induced beige adipogenesis in Dicer KO mice. High fat feeding reduced miR-10a-5p levels in ATMs of gWAT, and treatment of mice with a miR-10a-5p mimic suppressed pro-inflammatory responses, promoted the appearance of new white adipocytes in gWAT, and improved systemic glucose tolerance. CONCLUSIONS:These results demonstrate an important role of macrophage-generated microRNAs in adipogenic niches and identify miR-10a-5p as a key regulator that reduces adipose tissue inflammation and promotes therapeutic adipogenesis.

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Dataset Information

MicroRNA let-7c regulates macrophage polarization.

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MicroRNA let-7c regulates macrophage polarization.

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