title: Cleavage of p53-vimentin complex enhances tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis of rheumatoid arthritis synovial fibroblasts.
abstract: Rheumatoid arthritis synovial fibroblasts (RASFs) contribute to arthritic cartilage degradation. Although RASFs are normally resistant to apoptosis, Apo2L/tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-based gene therapy has been successfully used in a mouse model of arthritis. We investigated this further by treating human RASFs with nontoxic doses of the proteasome inhibitor lactacystin. Treatment induced cytosolic accumulation of p53 and enhanced the susceptibility of RASFs to apoptosis mediated by TRAIL-R2 (DR5) but not Fas. A specific role for p53 in TRAIL-R2-mediated apoptosis was indicated by the ability of p53 siRNA to significantly reduce RASF apoptosis and by the reduced apoptosis of RASFs bearing p53 mutations on treatment with anti-DR5 antibody or anti-DR5 antibody plus lactacystin. p53 immunoprecipitation followed by mass spectrometry identified a vimentin-p53 complex, an interaction that was confirmed by reciprocal vimentin-p53 immunoprecipitation and by co-immunofluorescence. Interestingly, human caspase-4 cleaved human vimentin, and blockade of caspase-4 with a chemical inhibitor or with specific siRNA significantly inhibited TRAIL-R2-mediated apoptosis of RASFs. Furthermore, blockade of caspase-4 was paralleled by persistence of a cytosolic pattern of p53 and absence of p53 translocation to the nucleus. Taken together, our findings suggest a unique role for caspase-4 in cleaving vimentin and releasing cytosolic p53 for nuclear translocation, events that may regulate the sensitivity of RASFs to receptor-mediated apoptosis.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, and the Birmingham Veterans Administration Medical Center, Birmingham, AL 35294-0007, USA.
authors.forename: Xinwen
authors.initials: X
authors.lastname: Yang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: Cunren
authors.initials: C
authors.lastname: Liu
authors.forename: William E
authors.initials: WE
authors.lastname: Grizzle
authors.forename: Shaohua
authors.initials: S
authors.lastname: Yu
authors.forename: Shuangqin
authors.initials: S
authors.lastname: Zhang
authors.forename: Stephen
authors.initials: S
authors.lastname: Barnes
authors.forename: William J
authors.initials: WJ
authors.lastname: Koopman
authors.forename: John D
authors.initials: JD
authors.lastname: Mountz
authors.forename: Robert P
authors.initials: RP
authors.lastname: Kimberly
authors.forename: Huang-Ge
authors.initials: HG
authors.lastname: Zhang
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D001172:Arthritis, Rheumatoid / Q000378:metabolism / Q000503:physiopathology*; D001692:Biological Transport; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004789:Enzyme Activation; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D053221:TNF-Related Apoptosis-Inducing Ligand; D014018:Tissue Distribution; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism; D014746:Vimentin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000906:Antibodies; D051017:Apoptosis Regulatory Proteins; D061945:Caspase Inhibitors; D008562:Membrane Glycoproteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human; C505653:TNFSF10 protein, human; C505640:Tnfrsf10b protein, mouse; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D025801:Ubiquitin; D014746:Vimentin; C067713:lactacystin; D020169:Caspases; D046988:Proteasome Endopeptidase Complex; D000111:Acetylcysteine