| First Author | Ji W | Year | 2018 |
| Journal | PLoS One | Volume | 13 |
| Issue | 12 | Pages | e0208474 |
| PubMed ID | 30513114 | Mgi Jnum | J:268066 |
| Mgi Id | MGI:6268843 | Doi | 10.1371/journal.pone.0208474 |
| Citation | Ji W, et al. (2018) Effects of acute hypoxia exposure with different durations on activation of Nrf2-ARE pathway in mouse skeletal muscle. PLoS One 13(12):e0208474 |
| abstractText | BACKGROUND: Hypoxia training enhances the endurance capacity of athletes. This response may in part be attributed to the hypoxia-induced increase in antioxidant capacity in skeletal muscles. Nuclear factor erythroid 2-related factor 2 (Nrf2), a key transcription factor which regulates the expression of genes via binding to the antioxidant-response element (ARE) of these genes, plays a crucial role in stimulating the body's defense system and potentially responds to hypoxia. Meanwhile, hypoxia-inducible factor-1alpha (HIF-1alpha) is an important player in protecting cells from hypoxic stress. The purpose of this study was to investigate the effects of acute hypoxia exposure with different durations on the activation of Nrf2-ARE pathway and a possible regulatory role of HIF-1alpha in these responses. METHODS: C57BL/6J mice were allocated into the non-hypoxia 0-hour, 6-hour, 24-hour, and 48-hour hypoxic exposure (11.2% oxygen) groups. The quadriceps femoris was collected immediately after hypoxia. Further, to investigate the possible role of HIF-1alpha, C2C12 myoblasts with HIF-1alpha knockdown by small interfering RNA (siRNA) and the inducible HIF-1alpha transgenic mice were employed. RESULTS: The results showed that 48-hour hypoxia exposure up-regulated protein expression of Nrf2, Nrf2/ARE binding activity and the transcription of antioxidative genes containing ARE (Sod1 and others) in mouse skeletal muscle. Moreover, HIF-1alpha siRNA group of C2C12 myoblasts showed a remarkable inhibition of Nrf2 protein expression and nuclear accumulation in hypoxia exposure for 72 hours compared with that in siRNA-Control group of the cells. In addition, HIF-1alpha transgenic mice gave higher Nrf2 protein expression, Nrf2/ARE binding activity and expressions of Nrf2-mediated antioxidative genes in their skeletal muscle, compared with those in the wild-type mice. CONCLUSIONS: The findings suggested that the acute hypoxia exposure could trigger the activation of Nrf2-ARE pathway, with longer duration associated with higher responses, and HIF-1alpha expression might be involved in promoting the Nrf2-mediated antioxidant responses in skeletal muscle. |
