RESUMO
Ubiquitin-mediated targeting of intracellular bacteria to the autophagy pathway is a key innate defence mechanism against invading microbes, including the important human pathogen Mycobacterium tuberculosis. However, the ubiquitin ligases responsible for catalysing ubiquitin chains that surround intracellular bacteria are poorly understood. The parkin protein is a ubiquitin ligase with a well-established role in mitophagy, and mutations in the parkin gene (PARK2) lead to increased susceptibility to Parkinson's disease. Surprisingly, genetic polymorphisms in the PARK2 regulatory region are also associated with increased susceptibility to intracellular bacterial pathogens in humans, including Mycobacterium leprae and Salmonella enterica serovar Typhi, but the function of parkin in immunity has remained unexplored. Here we show that parkin has a role in ubiquitin-mediated autophagy of M. tuberculosis. Both parkin-deficient mice and flies are sensitive to various intracellular bacterial infections, indicating parkin has a conserved role in metazoan innate defence. Moreover, our work reveals an unexpected functional link between mitophagy and infectious disease.
Assuntos
Drosophila melanogaster/imunologia , Drosophila melanogaster/microbiologia , Imunidade Inata/imunologia , Mycobacterium marinum/imunologia , Mycobacterium tuberculosis/imunologia , Salmonella typhimurium/imunologia , Ubiquitina-Proteína Ligases/imunologia , Animais , Autofagia/imunologia , Células da Medula Óssea/microbiologia , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Feminino , Lisina/metabolismo , Macrófagos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Mitofagia , Modelos Imunológicos , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/metabolismo , Poliubiquitina/química , Poliubiquitina/metabolismo , Simbiose/imunologia , Tuberculose/enzimologia , Tuberculose/imunologia , Tuberculose/microbiologia , Tuberculose/patologia , Ubiquitina/análise , Ubiquitina/química , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/química , Ubiquitina-Proteína Ligases/deficiência , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Ankylosing spondylitis (AS) is associated with antibodies to a heat shock puff on drosophila chromosomes. This observation was investigated by immunoblotting using extracts of the Schneider insect cell line and HeLa cells, before and after heat shock. An insect protein of 63 kilodaltons (but no equivalent human protein) was recognised by 21 (46%) of 46 serum samples from patients with AS, one of two patients with Reiter's syndrome, four (7%) of 60 patients with systemic lupus erythematosus, and two (4%) of 50 control subjects, but not by serum samples from patients with rheumatoid arthritis (RA). Previous heat shock did not appear to affect the strength of reaction, but ML-30, a monoclonal antibody to the mycobacterial 65 kilodalton heat shock protein (hsp65), also recognised an insect protein of 63 kilodaltons by immunoblotting. Antibodies to recombinant mycobacterial hsp65 were measured by enzyme linked immunosorbent assay (ELISA) in serum samples from patients with AS and RA. IgA binding to hsp65 was increased in 41% of AS and 19% of RA serum samples, but there was no correlation with detection of antibody to the insect 63 kilodalton protein.