Abstract 18939: Micro RNA-93 Promotes Macrophage M2 Polarization in Experimenal Peripheral Arterial Disease
Macrophages (MØ) were well known to play vital roles in promoting blood flow by arteriogenic induction in experimental Peripheral Arterial Disease (PAD). MØs depending on the cytokine milieu, exist in M1 or M2 polarization states (two extremes of polarization continuum). While M1-MØs are pro-inflammatory and anti-angiogenic, M2-MØs are anti-inflammatory and pro-angiogenic. We have previously demonstrated that Micro RNA-93 (Mir93) promotes angiogenesis and perfusion recovery in experimental PAD. However, the downstream mechanisms that operate in Mir93 mediated perfusion recovery in ischemic leg are not yet clear. In our current study we investigated the role of Mir93 in MØ polarization in vitro and in animal models of hind limb ischemic (HLI). We hypothesized that “Mir93 induction in ischemic muscle promotes M2-MØ polarization that improves tissue repair, survival and neovascularization in PAD”
Mir93 mimic transfection in Raw264.7 (MØ cell line) significantly induced Arginase-1 (M1 marker) expression and decreased inducible Nitric oxide synthase (iNOS) (M2 marker) expression compared to negative mimic in qPCR analysis. Bone marrow derived macrophages (BMDM) from MCM7-KO (Mir93 deficient mice) express significantly higher levels of iNOS compared to littermates under hypoxia serum starvation. Monocytes isolated from the bone marrow of MCM7-KO ischemic legs express significantly higher levels of iNOS compared to littermates. Conditioned medium from Antagomir-93 treated Raw264.7 MØs and MCM7-KO BMDM significantly decreased HUVEC capillary like tube formation on matrigel compared to negative antagomir treated or littermates. Flow cytometry analysis showed that MCM7-KO mice had significantly higher levels of M1-MØs correlating with decreased capillary density compared to litter mate controls. P<0.05 considered significant
We conclude that Mir93 plays a crucial role in inducing MØ-M2 polarization. Increased Mir93 levels in ischemic hind limb promote M2-MØ polarization that helps in recovery of ischemic leg by tissue repair and neovascularization. Ongoing experiments are aimed to determine whether Mir93 deficient MØs can inhibit perfusion recovery in littermates and the downstream targets of Mir93 that regulate MØ polarization in HLI
Author Disclosures: V.C. Ganta: Employment; Significant; 45000. A. Kutateladze: None. B. Annex: Research Grant; Significant; NIH. N. Leitinger: None.
- © 2015 by American Heart Association, Inc.