| First Author | MacLauchlan SC | Year | 2018 |
| Journal | Matrix Biol | Volume | 65 |
| Pages | 45-58 | PubMed ID | 28789925 |
| Mgi Jnum | J:258865 | Mgi Id | MGI:6121173 |
| Doi | 10.1016/j.matbio.2017.07.002 | Citation | MacLauchlan SC, et al. (2018) HIF-1alpha represses the expression of the angiogenesis inhibitor thrombospondin-2. Matrix Biol 65:45-58 |
| abstractText | Thrombospondin-2 (TSP2) is a potent inhibitor of angiogenesis whose expression is dynamically regulated following injury. In the present study, it is shown that HIF-1alpha represses TSP2 transcription. Specifically, in vitro studies demonstrate that the prolyl hydroxylase inhibitor DMOG or hypoxia decrease TSP2 expression in fibroblasts. This effect is shown to be via a transcriptional mechanism as hypoxia does not alter TSP2 mRNA stability and this effect requires the TSP2 promoter. In addition, the documented repressive effect of nitric oxide (NO) on TSP2 is shown to be non-canonical and involves stabilization of hypoxia inducible factor-1a (HIF-1alpha). The regulation of TSP2 by hypoxia is supported by the in vivo observation that TSP2 has spatiotemporal expression distinct from regions of hypoxia in gastrocnemius muscle following murine hindlimb ischemia (HLI). A role for TSP2 regulation by HIF-1alpha is supported by the dysregulation of TSP2 expression in SM22alpha-cre HIF-1alpha KO mice following HLI. Indeed, there is a reduction in blood flow recovery in the SM22a-cre HIF-1alpha KO mice compared to littermate controls following HLI surgery, associated with impaired recovery and increased TSP2 levels. Moreover, SM22alpha-cre HIF-1alpha KO smooth muscle cells mice have increased TSP2 mRNA levels that persist in hypoxia. These findings identify a novel, ischemia-induced pro-angiogenic mechanism involving the transcriptional repression of TSP2 by HIF-1alpha. |
