RESUMO
Mutations in the nucleotide-binding oligomerization domain protein 12 (NLRP12) cause recurrent episodes of serosal inflammation. Here we show that NLRP12 efficiently sequesters HSP90 and promotes K48-linked ubiquitination and degradation of NOD2 in response to bacterial muramyl dipeptide (MDP). This interaction is mediated by the linker-region proximal to the nucleotide-binding domain of NLRP12. Consequently, the disease-causing NLRP12 R284X mutation fails to repress MDP-induced NF-κB and subsequent activity of the JAK/STAT signaling pathway. While NLRP12 deficiency renders septic mice highly susceptible towards MDP, a sustained sensing of MDP through NOD2 is observed among monocytes lacking NLRP12. This loss of tolerance in monocytes results in greater colonization resistance towards Citrobacter rodentium. Our data show that this is a consequence of NOD2-dependent accumulation of inflammatory mononuclear cells that correlates with induction of interferon-stimulated genes. Our study unveils a relevant process of tolerance towards the gut microbiota that is exploited by an attaching/effacing enteric pathogen.
Assuntos
Acetilmuramil-Alanil-Isoglutamina/metabolismo , Cápsulas Bacterianas/metabolismo , Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Proteínas de Choque Térmico HSP90/metabolismo , Tolerância Imunológica/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Adaptadora de Sinalização NOD2/metabolismo , Animais , Linhagem Celular , Infecções por Enterobacteriaceae/microbiologia , Microbioma Gastrointestinal/imunologia , Células HEK293 , Humanos , Inflamação/imunologia , Inflamação/microbiologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Knockout , NF-kappa B/metabolismo , UbiquitinaçãoRESUMO
Prominent changes in the gut microbiota (referred to as "dysbiosis") play a key role in the development of allergic disorders, but the underlying mechanisms remain unknown. Study of the delayed-type hypersensitivity (DTH) response in mice contributed to our knowledge of the pathophysiology of human allergic contact dermatitis. Here we report a negative regulatory role of the RIG-I-like receptor adaptor mitochondrial antiviral signaling (MAVS) on DTH by modulating gut bacterial ecology. Cohousing and fecal transplantation experiments revealed that the dysbiotic microbiota of Mavs-/- mice conferred a proallergic phenotype that is communicable to wild-type mice. DTH sensitization coincided with increased intestinal permeability and bacterial translocation within lymphoid organs that enhanced DTH severity. Collectively, we unveiled an unexpected impact of RIG-I-like signaling on the gut microbiota with consequences on allergic skin disease outcome. Primarily, these data indicate that manipulating the gut microbiota may help in the development of therapeutic strategies for the treatment of human allergic skin pathologies.
