title: Prolyl hydroxylase 3 (PHD3) modulates catabolic effects of tumor necrosis factor-α (TNF-α) on cells of the nucleus pulposus through co-activation of nuclear factor κB (NF-κB)/p65 signaling.
abstract: Recent studies suggest a differential role of prolyl hydroxylase (PHD) isoforms in controlling hypoxia-inducible factor (HIF)-α degradation and activity in nucleus pulposus (NP) cells. However, the regulation and function of PHDs under inflammatory conditions that characterize disc disease are not yet known. Here, we show that in NP cells, TNF-α and IL-1β induce PHD3 expression through NF-κB. Lentiviral delivery of Sh-p65 and Sh-IKKβ confirms that cytokine-mediated PHD3 expression is NF-κB-dependent. It is noteworthy that although both cytokines induce HIF activity, mechanistic studies using Sh-HIF-1α and PHD3 promoter/enhancer constructs harboring well characterized hypoxia response element (HRE) show lack of HIF involvement in cytokine-mediated PHD3 expression. Loss-of-function studies clearly indicate that PHD3 serves as a co-activator of NF-κB signaling activity in NP cells; PHD3 interacts with, and co-localizes with, p65. We observed that when PHD3 is silenced, there is a significant decrease in TNF-α-induced expression of catabolic markers that include ADAMTS5, syndecan4, MMP13, and COX2, and at the same time, there is restoration of aggrecan and collagen type II expression. It is noteworthy that hydroxylase function of PHDs is not required for mediating cytokine-dependent gene expression. These findings show that by enhancing the activity of inflammatory cytokines, PHD3 may serve a critical role in degenerative disc disease.
authors.affiliation: Department of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Fujita
authors.forename: Shilpa S
authors.initials: SS
authors.lastname: Gogate
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Chiba
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Irving M
authors.initials: IM
authors.lastname: Shapiro
authors.forename: Makarand V
authors.initials: MV
authors.lastname: Risbud
mesh_terms: D051722:ADAM Proteins / Q000096:biosynthesis / Q000235:genetics; D000071116:ADAMTS5 Protein; D000818:Animals; D002478:Cells, Cultured; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000096:biosynthesis / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D049308:Dioxygenases / Q000096:biosynthesis* / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D020868:Gene Silencing; D006801:Humans; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D017874:Immediate-Early Proteins / Q000096:biosynthesis* / Q000235:genetics; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D007403:Intervertebral Disc / Q000378:metabolism* / Q000473:pathology; D055959:Intervertebral Disc Degeneration / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D053509:Matrix Metalloproteinase 13 / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D020218:Response Elements / Q000235:genetics; D015398:Signal Transduction; D053671:Syndecan-4 / Q000096:biosynthesis / Q000235:genetics; D051996:Transcription Factor RelA / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism*
chemical_list: D024043:Collagen Type II; D004268:DNA-Binding Proteins; C508585:IL1B protein, human; D017874:Immediate-Early Proteins; D053583:Interleukin-1beta; C498143:RELA protein, human; C498145:Rela protein, rat; C508304:SDC4 protein, human; C508307:Sdc4 protein, rat; D053671:Syndecan-4; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D049308:Dioxygenases; C488894:EGLN3 protein, human; C087100:Egln3 protein, rat; D064799:Hypoxia-Inducible Factor-Proline Dioxygenases; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; C489691:Ptgs2 protein, rat; D051722:ADAM Proteins; D000071116:ADAMTS5 Protein; C121532:ADAMTS5 protein, human; C518696:Adamts5 protein, rat; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat