RESUMO
Cytoplasmic linker protein 170 (CLIP170) is a CAP-Gly domain-containing protein that is associated with the plus end of growing microtubules and implicated in various cellular processes, including the regulation of microtubule dynamics, cell migration, and intracellular transport. Our studies revealed a previously unrecognized property and role of CLIP170. We identified CLIP170 as one of the interacting partners of Brucella effector protein TcpB that negatively regulates TLR2 and TLR4 signaling. In this study, we demonstrate that CLIP170 interacts with the TLR2 and TLR4 adaptor protein TIRAP. Furthermore, our studies revealed that CLIP170 induces ubiquitination and subsequent degradation of TIRAP to negatively regulate TLR4-mediated proinflammatory responses. Overexpression of CLIP170 in mouse macrophages suppressed the LPS-induced expression of IL-6 and TNF-α whereas silencing of endogenous CLIP170 potentiated the levels of proinflammatory cytokines. In vivo silencing of CLIP170 in C57BL/6 mice by CLIP170-specific small interfering RNA enhanced LPS-induced IL-6 and TNF-α expression. Furthermore, we found that LPS modulates the expression of CLIP170 in mouse macrophages. Overall, our experimental data suggest that CLIP170 serves as an intrinsic negative regulator of TLR4 signaling that targets TIRAP.
Assuntos
Glicoproteínas de Membrana/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas de Neoplasias/metabolismo , Receptores de Interleucina-1/metabolismo , Transdução de Sinais , Receptor 4 Toll-Like/metabolismo , Animais , Biomarcadores , Linhagem Celular , Citocinas/metabolismo , Expressão Gênica , Inativação Gênica , Humanos , Imuno-Histoquímica , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Proteínas Associadas aos Microtúbulos/genética , NF-kappa B/metabolismo , Proteínas de Neoplasias/genética , Ligação Proteica , Proteólise , Interferência de RNA , RNA Interferente Pequeno/genética , UbiquitinaçãoRESUMO
Brucellosis is the most frequent zoonotic disease worldwide, with over 500,000 new human infections every year. Brucella melitensis, the most virulent species in humans, primarily affects goats and the zoonotic transmission occurs by ingestion of unpasteurized milk products or through direct contact with fetal tissues. Brucellosis is endemic in India but no information is available on population structure and genetic diversity of Brucella spp. in India. We performed multilocus sequence typing of four B. melitensis strains isolated from naturally infected goats from India. For more detailed genetic characterization, we carried out whole genome sequencing and comparative genome analysis of one of the B. melitensis isolates, Bm IND1. Genome analysis identified 141 unique SNPs, 78 VNTRs, 51 Indels, and 2 putative prophage integrations in the Bm IND1 genome. Our data may help to develop improved epidemiological typing tools and efficient preventive strategies to control brucellosis.