Abstract 12081: Nitric Oxide Impairs Angiogenesis by Bone Marrow Mesenchymal Stem Cells
Introduction: Mesenchymal stem cells (MSCs) participate in blood vessel formation; however, the mechanism(s) underlying this process remain elusive. We assessed the role of nitric oxide (NO) by comparing MSC-mediated angiogenesis in mice lacking S-nitrosoglutathione reductase (GSNOR−/−), a denitrosylase that metabolizes intracellular GSNO. Hypothesis: Here we tested the hypothesis that nitric oxide signaling mediated via GSNOR regulates MSC angiogenesis.
Method: Bone marrow-derived MSCs isolated from WT and GSNOR−/− mice or humans (hMSCs) were grown in endothelial growth media followed by 24h in Matrigel (in vitro), in the presence of either vehicle, L-NAME (a nitric oxide synthase (NOS) inhibitor) or GSNO and SNAP (a nitric oxide donors). NO production and NOS expression by MSCs was assessed via DAF-2A diacetate and quantitative RT-PCR. We additionally, used an allograft assay to study the in vivo angiogenic potential of the murine MSCs.
Results: MSCs from GSNOR−/− mice formed fewer (29.9±12.0 vs. 50.0±15.4, p<0.001) and shorter (62.8±34.6 µm vs. 105.9±57.0 µm, p<0.001) tubes than MSCs derived from WT mice in vitro. NOS inhibition with L-NAME treatment completely normalized the number (49.9±14.8, p<0.001) and length (82.8±42.5 µm, p<0.001) of GSNOR−/− tubes. Treatment of murine and hMSCs with NO donors (GSNO and SNAP) reduced the capillary tube formation by ∼50% both in number (p<0.001) and length (p<0.001), confirming the role of NO signaling in angiogenesis. Importantly, when transplanted in vivo GSNOR−/− MSCs had impaired blood vessel formation (10.2±2.7 vs. 1.84±1.3 p<0.01), and reduced endothelial differentiation compared to WT MSCs (12.5±5.7 vs. 7.7±9.0% p<0.02). Interestingly, in order to keep the maintenance of NO production, MSCs from GSNOR−/− had higher NOS1 expression than WT MSCs.
Conclusion: Together these findings showed diminished angiogenesis mediated by MSCs from GSNOR knockout mice, thereby demonstrating an inhibitory effect of s-nitrosylation signaling in angiogenesis. Accordingly disease states characterized by NO deficient environments may trigger MSC mediated angiogenesis.
- © 2012 by American Heart Association, Inc.