Regulation of monocyte functional heterogeneity by miR-146a
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ABSTRACT: Monocytes and their lineage descendants serve as a central defense system against infection and injury but if uncontrolled can also promote an excessive pathological inflammatory response. Therefore a current research goal is to understand how the organism controls the number and function of monocytes and how these variables can be tailored in therapy. Considering the evidence that monocytes are heterogeneous and exist in at least two subsets committed to divergent functions, we investigated whether distinct factors regulate the balance between monocyte subset responses in vivo. We identified a microRNA (miRNA), miR-146a, which is differentially regulated both in mouse (Ly-6Chi and Ly-6Clo) and human (CD14hi and CD14lo CD16+) monocyte subsets. The single miRNA was found to significantly control the amplitude of the Ly-6Chi monocyte response during inflammatory challenge whereas it did not affect Ly-6Clo cells. miR-146a–mediated regulation was cell-intrinsic and depended on Relb, a member of the non-canonical NF-κB/Rel family, which is identified here as a novel miR-146a target. These observations provide novel mechanistic insights into the molecular events that regulate monocyte functional heterogeneity and identify therapeutic targets that can influence the quality and quantity of monocyte responses.
Project description:Monocytes and their lineage descendants serve as a central defense system against infection and injury but if uncontrolled can also promote an excessive pathological inflammatory response. Therefore a current research goal is to understand how the organism controls the number and function of monocytes and how these variables can be tailored in therapy. Considering the evidence that monocytes are heterogeneous and exist in at least two subsets committed to divergent functions, we investigated whether distinct factors regulate the balance between monocyte subset responses in vivo. We identified a microRNA (miRNA), miR-146a, which is differentially regulated both in mouse (Ly-6Chi and Ly-6Clo) and human (CD14hi and CD14lo CD16+) monocyte subsets. The single miRNA was found to significantly control the amplitude of the Ly-6Chi monocyte response during inflammatory challenge whereas it did not affect Ly-6Clo cells. miR-146a–mediated regulation was cell-intrinsic and depended on Relb, a member of the non-canonical NF-κB/Rel family, which is identified here as a novel miR-146a target. These observations provide novel mechanistic insights into the molecular events that regulate monocyte functional heterogeneity and identify therapeutic targets that can influence the quality and quantity of monocyte responses. 4 samples of splenic Ly-6Chi monocytes, 4 samples of splenic Ly-6Clo monocytes; both isolated from C57BL/6 mice. Each sample was generated by fluorecsence activated cell sorting from the pooled spleens of 10 mice.
Project description:To gain insight into the mechanisms underlying miR-146a-mediated modulation of Ly6Chigh monocyte function, we compared the expression profiles of Ly6Chigh and Ly6Clow monocytes in miR-146a+/+ (WT) versus miR-146a-/- (KO) conditions.
Project description:This SuperSeries is composed of the following subset Series: GSE32364: Murine blood monocyte subsets GSE32370: Regulation of monocyte functional heterogeneity by miR-146a Refer to individual Series
Project description:A long-prevailing model has held that the “seed” region (nucleotides 2-8) of a microRNA is typically sufficient to mediate target recognition and repression. However, numerous recent studies, both within the context of defining miRNA/target pairs by direct physical association and by directly assessing this model in vivo in C. elegans have brought this model into question. To test the importance of miRNA 3' pairing in vivo, in a mammalian system, we engineered a mutant murine mir-146a allele in which the 5' half of the mature microRNA retains the sequence of the wild-type mir-146a but the 3ʹ half has been altered to be anti-complementary to the wild-type miR-146a sequence. Mice homozygous or hemizygous for this mutant allele are phenotypically indistinguishable from wild-type controls and do not recapitulate any of the immunopathology previously described for mir-146a-null mice. Our results strongly support the conclusion that 3ʹ pairing is dispensable in the context of the function of a key mammalian microRNA.
Project description:miR-146a is a known anti-inflammatory miRNA. Intringuigly, it is overexpressed in RAS-induced senescent cells which is accompanied with a rich pro-inflammatoy secretpry phenotype. We aim to study possible sponges for miR-146a.
Project description:MiR-146a is an important regulator of innate inflammatory responses and is also implicated in cell death and survival. Here, we identified microglia as the main cellular source of miR-146a among mouse CNS resident cells. We further characterized the phenotype of miR-146a KO microglia cells during in vivo demyelination induced by cuprizone (CPZ) and found reduced number of CD11c+ microglia in the KO compared to WT mice. Microglia were also isolated from the brain, and the proteome was analyzed by liquid chromatography mass spectrometry.
Project description:miR-146a is a known anti-inflammatory miRNA. Intringuigly, it is overexpressed in RAS-induced senescent cells which is accompanied with a rich pro-inflammatoy secretpry phenotype. We aim to study possible sponges for miR-146a.
Project description:Monocytes and their lineage descendants serve as a central defense system against infection and injury but if uncontrolled can also promote an excessive pathological inflammatory response. Therefore a current research goal is to understand how the organism controls the number and function of monocytes and how these variables can be tailored in therapy. Considering the evidence that monocytes are heterogeneous and exist in at least two subsets committed to divergent functions, we investigated whether distinct factors regulate the balance between monocyte subset responses in vivo. Here we investigate the differential expression of mRNA among murine steady-state monocyte subsets. Blood was drawn from healthy C57BL/6 donors. For each biological replicate 1000 monocytes of the Ly-6Chi and Ly-6Clo phenotype were isolated from the blood sample through fluorescence activated cell sorting.
Project description:Human CD4+ Total memory cells (CD4+CD25-CD45RA-CCR7+/-) were activated with anti-CD3/anti-CD28 antibodies and transfected with biotinylated miR-146a mimic or biotinylated mimic negative control by Exiqon. After 24h cells were lysed and miRNA:mRNA complexes pulled-down with streptavidin agarose O/N at 4°C. RNA was then purified using TRI-reagent and RNA zymospin columns. Four independent donors were used for this experiment. Total RNA was sequenced in 2 lanes, paired ends. This experiment is assessing direct targets bound by miR-146a in human T cells.
Project description:This study was designed to explore the role of miRNA-146a (miR-146a) and its target genes in the endothelial cells. In this study we have demonstrated that lipopolysaccharide (LPS) induced upregulation of miR-146a in the human umbilical vein endothelial cells (HUVEC) and the induction was blocked by the silencing of the toll-like receptors (TLRs) adaptor molecules MyD88 and nonspecific NF-κB inhibitor BAY 11-7082. In addition, knockdown of miR-146a by transfection of the locked nucleic acid (LNA)-antimiR-146a significantly decreased the increased cell migration and tube formation induced by LPS. A combined analysis of the bioinformatics miRanda algorithms and the whole genome expression microarray of the immunoprecipitated Ago2 ribonucleoprotein complex identified 14 transcripts as the potential target genes. Subsequent transfection with miR-146a precursor pre-miR-146a into the HUVEC validated that the CARD10 was the target gene of the miR-146a both in the transcript and protein level.