title: Central role for endothelial human deneddylase-1/SENP8 in fine-tuning the vascular inflammatory response.
abstract: A deeper understanding of the mechanisms that control responses to inflammation is critical to the development of effective therapies. We sought to define the most proximal regulators of the Cullin (Cul)-RING ligases, which play a central role in the stabilization of NF-κB and hypoxia-inducible factor (HIF). In these studies, we identify the human deneddylase-1 (SENP8) as a key regulator of Cul neddylation response in vitro and in vivo. Using human microvascular endothelial cells (HMECs), we examined inflammatory responses to LPS or TNF-α by assessing Cul neddylation status, NF-κB and HIF-1α stabilization, and inflammatory cytokine secretion. HMECs with an intact neddylation pathway showed a time-dependent induction of Cul-1 neddylation, nuclear translocation of NF-κB, stabilization of HIF-1α, and increased NF-κB/HIF-α promoter activity in response to LPS. HMECs lacking SENP8 were unable to neddylate Cul-1 and subsequently were unable to activate NF-κB or HIF-1α. Pharmacological targeting of neddylation (MLN4924) significantly abrogated NF-κB responses, induced HIF-1α promoter activity, and reduced secretion of TNF-α-elicited proinflammatory cytokines. MLN4924 stabilized HIF and abrogated proinflammatory responses while maintaining anti-inflammatory IL-10 responses in vivo following LPS administration. These studies identify SENP8 as a proximal regulator of Cul neddylation and provide an important role for SENP8 in fine-tuning the inflammatory response. Moreover, our findings provide feasibility for therapeutic targeting of the Culs during inflammation.
authors.affiliation: Mucosal Inflammation Program, Department of Medicine and Immunology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
authors.forename: Stefan F
authors.initials: SF
authors.lastname: Ehrentraut
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Kominsky
authors.forename: Louise E
authors.initials: LE
authors.lastname: Glover
authors.forename: Eric L
authors.initials: EL
authors.lastname: Campbell
authors.forename: Caleb J
authors.initials: CJ
authors.lastname: Kelly
authors.forename: Brittelle E
authors.initials: BE
authors.lastname: Bowers
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Bayless
authors.forename: Sean P
authors.initials: SP
authors.lastname: Colgan
mesh_terms: D002478:Cells, Cultured; D044842:Cullin Proteins / Q000378:metabolism / Q000502:physiology*; D010450:Endopeptidases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*; D004792:Enzyme Precursors / Q000378:metabolism / Q000502:physiology; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D018836:Inflammation Mediators / Q000502:physiology*; D008833:Microcirculation / Q000276:immunology; D000075687:NEDD8 Protein; D014452:Ubiquitins / Q000378:metabolism / Q000502:physiology*
chemical_list: D044842:Cullin Proteins; D004792:Enzyme Precursors; D018836:Inflammation Mediators; D000075687:NEDD8 Protein; C082860:NEDD8 protein, human; D014452:Ubiquitins; D010450:Endopeptidases; C477008:SENP8 protein, human