RESUMO
Virulent infectious agents such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and methicillin-resistant Staphylococcus aureus (MRSA) induce tissue damage that recruits neutrophils, monocyte, and macrophages, leading to T cell exhaustion, fibrosis, vascular leak, epithelial cell depletion, and fatal organ damage. Neutrophils, monocytes, and macrophages recruited to pathogen-infected lungs, including SARS-CoV-2-infected lungs, express phosphatidylinositol 3-kinase gamma (PI3Kγ), a signaling protein that coordinates both granulocyte and monocyte trafficking to diseased tissues and immune-suppressive, profibrotic transcription in myeloid cells. PI3Kγ deletion and inhibition with the clinical PI3Kγ inhibitor eganelisib promoted survival in models of infectious diseases, including SARS-CoV-2 and MRSA, by suppressing inflammation, vascular leak, organ damage, and cytokine storm. These results demonstrate essential roles for PI3Kγ in inflammatory lung disease and support the potential use of PI3Kγ inhibitors to suppress inflammation in severe infectious diseases.
Assuntos
COVID-19 , Classe Ib de Fosfatidilinositol 3-Quinase , Inflamação , SARS-CoV-2 , Animais , Humanos , Camundongos , Permeabilidade Capilar/efeitos dos fármacos , Classe Ib de Fosfatidilinositol 3-Quinase/metabolismo , COVID-19/patologia , Tratamento Farmacológico da COVID-19 , Síndrome da Liberação de Citocina/tratamento farmacológico , Inflamação/patologia , Pulmão/patologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase/uso terapêutico , SARS-CoV-2/fisiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/patologiaRESUMO
Myeloid cells play key roles in cancer immune suppression and tumor progression. In response to tumor derived factors, circulating monocytes and granulocytes extravasate into the tumor parenchyma where they stimulate angiogenesis, immune suppression and tumor progression. Chemokines, cytokines and interleukins stimulate PI3Kγ-mediated Rap1 activation, leading to conformational changes in integrin α4ß1 that promote myeloid cell extravasation and tumor inflammation Here we show that PI3Kγ activates a high molecular weight form of myosin light chain kinase, MLCK210, that promotes myosin-dependent Rap1 GTP loading, leading to integrin α4ß1 activation. Genetic or pharmacological inhibition of MLCK210 suppresses integrin α4ß1 activation, as well as tumor inflammation and progression. These results demonstrate a critical role for myeloid cell MLCK210 in tumor inflammation and serve as basis for the development of alternative approaches to develop immune oncology therapeutics.