PHD3 is a transcriptional coactivator of HIF-1? in nucleus pulposus cells independent of the PKM2-JMJD5 axis.

ABSTRACT: The role of prolyl hydroxylase (PHD)-3 as a hypoxia inducible factor (HIF)-1? cofactor is controversial and remains unknown in skeletal tissues. We investigated whether PHD3 controls HIF-1 transcriptional activity in nucleus pulposus (NP) cells through the pyruvate kinase muscle (PKM)-2-Jumonji domain--containing protein (JMJD5) axis. PHD3^-/- mice (12.5 mo old) showed increased incidence of intervertebral disc degeneration with a concomitant decrease in expression of the HIF-1? targets VEGF-A, glucose transporter-1, and lactate dehydrogenase A. PHD3 silencing decreased hypoxic activation of HIF-1? C-terminal transactivation domain (C-TAD), but not HIF-1?-N-terminal-(N)-TAD or HIF-2?-TAD. Moreover, PHD3 suppression in NP cells resulted in decreased HIF-1? enrichment on target promoters and lower expression of select HIF-1 targets. Contrary to other cell types, manipulation of PKM2 and JMJD5 levels had no effect on HIF-1 activity in NP cells. Likewise, stabilization of tetrameric PKM2 by a chemical approach had no effect on PHD3-dependent HIF-1 activity. Coimmunoprecipitation assays showed lack of association between HIF-1? and PKM2 in NP cells. Results support the role of the PHD3 as a cofactor for HIF-1, independent of PKM2-JMJD5.-Schoepflin, Z. R., Silagi, E. S., Shapiro, I. M., Risbud, M. V. PHD3 is a transcriptional coactivator of HIF-1? in nucleus pulposus cells independent of the PKM2-JMJD5 axis.

SUBMITTER: Schoepflin ZR 

PROVIDER: S-EPMC5572688 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature