title: A role for tumor necrosis factor receptor-2 and receptor-interacting protein in programmed necrosis and antiviral responses.
abstract: Members of the tumor necrosis factor (TNF) receptor (TNFR) superfamily are potent regulators of apoptosis, a process that is important for the maintenance of immune homeostasis. Recent evidence suggests that TNFR-1 and Fas and TRAIL receptors can also trigger an alternative form of cell death that is morphologically distinct from apoptosis. Because distinct molecular components including the serine/threonine protein kinase receptor-interacting protein (RIP) are required, we have referred to this alternative form of cell death as "programmed necrosis." We show that TNFR-2 signaling can potentiate programmed necrosis via TNFR-1. When cells were pre-stimulated through TNFR-2 prior to subsequent activation of TNFR-1, enhanced cell death and recruitment of RIP to the TNFR-1 complex were observed. However, TNF-induced programmed necrosis was normally inhibited by caspase-8 cleavage of RIP. To ascertain the physiological significance of RIP and programmed necrosis, we infected Jurkat cells with vaccinia virus (VV) and found that VV-infected cells underwent programmed necrosis in response to TNF, but deficiency of RIP rescued the infected cells from TNF-induced cytotoxicity. Moreover, TNFR-2-/- mice exhibited reduced inflammation in the liver and defective viral clearance during VV infection. Interestingly, death effector domain-containing proteins such as MC159, E8, K13, and cellular FLIP, but not the apoptosis inhibitors Bcl-xL, p35, and XIAP, potently suppressed programmed necrosis. Thus, TNF-induced programmed necrosis is facilitated by TNFR-2 signaling and caspase inhibition and may play a role in controlling viral infection.
authors.affiliation: Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. francis.chan@umassmed.edu
authors.forename: Francis Ka-Ming
authors.initials: FK
authors.lastname: Chan
authors.forename: Joanna
authors.initials: J
authors.lastname: Shisler
authors.forename: Jacqueline G
authors.initials: JG
authors.lastname: Bixby
authors.forename: Martin
authors.initials: M
authors.lastname: Felices
authors.forename: Lixin
authors.initials: L
authors.lastname: Zheng
authors.forename: Michael
authors.initials: M
authors.lastname: Appel
authors.forename: Jan
authors.initials: J
authors.lastname: Orenstein
authors.forename: Bernard
authors.initials: B
authors.lastname: Moss
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lenardo
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000494:pharmacology; D006801:Humans; D019169:Jurkat Cells; D051379:Mice; D018345:Mice, Knockout; D009336:Necrosis; D011506:Proteins / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014615:Vaccinia / Q000276:immunology / Q000473:pathology; D014777:Virus Diseases / Q000276:immunology / Q000473:pathology*
chemical_list: D015703:Antigens, CD; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha; C506249:RIPK1 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; C506251:Ripk1 protein, mouse; C505530:CASP8 protein, human; C506433:CASP9 protein, human; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases