GSE104853
MicroRNA-125a-5p overexpression in human macrophages
Systemic juvenile idiopathic arthritis (SJIA) is a severe childhood arthropathy with features of autoinflammation. Monocytes and macrophages in SJIA have a complex phenotype with both pro- and anti-inflammatory properties that combine features of several well characterized in vitro conditions used to activate macrophages.  An important anti-inflammatory phenotype is expression of CD163, a scavenger receptor that sequesters toxic pro-inflammatory complexes that is highly expressed in both active SJIA and macrophage activation syndrome (MAS).  CD163 is most strongly upregulated by IL-10 (M(IL-10)), and not by other conditions that reflect features seen in SJIA monocytes such as M(LPS+IC).  MicroRNA play key roles balancing and integrating cellular signals such as those in macrophage polarization, and as such we hypothesize microRNA regulate macrophage functional responses in SJIA including CD163 expression in vitro.  We find that two microRNA previously found to be elevated in active SJIA, miR-125a-5p and miR-181c, significantly reduced macrophage CD163 expression through two distinct mechanisms.  Neither microRNA was elevated in M(IL-10) with robust CD163 expression, but were instead induced in M(LPS+IC) where they restricted CD163 mRNA expression.  Mir-181 species directly targeted CD163 mRNA for degradation.  In contrast, transcriptome analysis of miR-125a-5p overexpression identified “cytokine-cytokine receptor interactions” as the most significantly repressed gene pathway, including decreased IL10RA, which is required for IL-10-mediated CD163 expression. Finally, overexpression of miR-181c inhibited CD163 anti-inflammatory responses to hemoglobin or high mobility group box 1 complexes. Together, these data show that microRNA utilize multiple mechanisms to integrate well characterized polarization phenotypes and regulate macrophage functional properties seen in SJIA. Overall design: THP-1 human monocytic cells were transfected in triplicate with negative control microRNA mimic or miR-125a-5p mimic. RNA extracted 24hours after transfection