RESUMO
We previously reported that TLR4(-/-) mice are refractory to mouse-adapted A/PR/8/34 (PR8) influenza-induced lethality and that therapeutic administration of the TLR4 antagonist Eritoran blocked PR8-induced lethality and acute lung injury (ALI) when given starting 2 days post infection. Herein we extend these findings: anti-TLR4- or -TLR2-specific IgG therapy also conferred significant protection of wild-type (WT) mice from lethal PR8 infection. If treatment is initiated 3 h before PR8 infection and continued daily for 4 days, Eritoran failed to protect WT and TLR4(-/-) mice, implying that Eritoran must block a virus-induced, non-TLR4 signal that is required for protection. Mechanistically, we determined that (i) Eritoran blocks high-mobility group B1 (HMGB1)-mediated, TLR4-dependent signaling in vitro and circulating HMGB1 in vivo, and an HMGB1 inhibitor protects against PR8; (ii) Eritoran inhibits pulmonary lung edema associated with ALI; (iii) interleukin (IL)-1ß contributes significantly to PR8-induced lethality, as evidenced by partial protection by IL-1 receptor antagonist (IL-1Ra) therapy. Synergistic protection against PR8-induced lethality was achieved when Eritoran and the antiviral drug oseltamivir were administered starting 4 days post infection. Eritoran treatment does not prevent development of an adaptive immune response to subsequent PR8 challenge. Overall, our data support the potential of a host-targeted therapeutic approach to influenza infection.
Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Antivirais/farmacologia , Dissacarídeos/farmacologia , Imunoglobulina G/farmacologia , Infecções por Orthomyxoviridae/tratamento farmacológico , Oseltamivir/farmacologia , Fosfatos Açúcares/farmacologia , Lesão Pulmonar Aguda/imunologia , Lesão Pulmonar Aguda/mortalidade , Lesão Pulmonar Aguda/virologia , Animais , Sinergismo Farmacológico , Feminino , Regulação da Expressão Gênica , Proteína HMGB1/antagonistas & inibidores , Proteína HMGB1/genética , Proteína HMGB1/imunologia , Imunidade Inata , Proteína Acessória do Receptor de Interleucina-1/antagonistas & inibidores , Proteína Acessória do Receptor de Interleucina-1/genética , Proteína Acessória do Receptor de Interleucina-1/imunologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Terapia de Alvo Molecular , Orthomyxoviridae/efeitos dos fármacos , Orthomyxoviridae/crescimento & desenvolvimento , Orthomyxoviridae/patogenicidade , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/virologia , Transdução de Sinais , Análise de Sobrevida , Receptor 2 Toll-Like/antagonistas & inibidores , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/imunologia , Receptor 4 Toll-Like/antagonistas & inibidores , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/imunologiaRESUMO
Resolution of severe Respiratory Syncytial Virus (RSV)-induced bronchiolitis is mediated by alternatively activated macrophages (AA-Mφ) that counteract cyclooxygenase (COX)-2-induced lung pathology. Herein, we report that RSV infection of 5-lipoxygenase (LO)(-/-) and 15-LO(-/-) macrophages or mice failed to elicit AA-Mφ differentiation and concomitantly exhibited increased COX-2 expression. Further, RSV infection of 5-LO(-/-) mice resulted in enhanced lung pathology. Pharmacologic inhibition of 5-LO or 15-LO also blocked differentiation of RSV-induced AA-Mφ in vitro and, conversely, treatment of 5-LO(-/-) macrophages with downstream products, lipoxin A4 and resolvin E1, but not leukotriene B4 or leukotriene D4, partially restored expression of AA-Mφ markers. Indomethacin blockade of COX activity in RSV-infected macrophages increased 5-LO and 15-LO, as well as arginase-1 mRNA expression. Treatment of RSV-infected mice with indomethacin also resulted not only in enhanced lung arginase-1 mRNA expression and decreased COX-2, but also decreased lung pathology in RSV-infected 5-LO(-/-) mice. Treatment of RSV-infected cotton rats with a COX-2-specific inhibitor resulted in enhanced lung 5-LO mRNA and AA-Mφ marker expression. Together, these data suggest a novel therapeutic approach for RSV that promotes AA-Mφ differentiation by activating the 5-LO pathway.
Assuntos
Araquidonato 5-Lipoxigenase/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/metabolismo , Vírus Sinciciais Respiratórios , Transdução de Sinais , Animais , Araquidonato 15-Lipoxigenase/genética , Araquidonato 15-Lipoxigenase/metabolismo , Araquidonato 5-Lipoxigenase/genética , Inibidores de Ciclo-Oxigenase/farmacologia , Modelos Animais de Doenças , Ativação Enzimática , Regulação da Expressão Gênica , Ativação de Macrófagos/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/virologia , Camundongos , Camundongos Knockout , Prostaglandina-Endoperóxido Sintases/metabolismo , RNA Mensageiro/genética , Ratos , Infecções por Vírus Respiratório Sincicial/genética , Infecções por Vírus Respiratório Sincicial/patologia , Infecções por Vírus Respiratório Sincicial/virologiaRESUMO
Severe respiratory syncytial virus (RSV)-induced bronchiolitis has been associated with a mixed "Th1" and "Th2" cytokine storm. We hypothesized that differentiation of "alternatively activated" macrophages (AA-M phi) would mediate the resolution of RSV-induced lung injury. RSV induced interleukin (IL)-4 and IL-13 by murine lung and peritoneal macrophages, IL-4R alpha/STAT6-dependent AA-M phi differentiation, and significantly enhanced inflammation in the lungs of IL-4R alpha(-/-) mice. Adoptive transfer of wildtype macrophages to IL-4R alpha(-/-) mice restored RSV-inducible AA-M phi phenotype and diminished lung pathology. RSV-infected Toll-like receptor (TLR)4(-/-) and interferon (IFN)-beta(-/-) macrophages and mice also failed to express AA-M phi markers, but exhibited sustained proinflammatory cytokine production (e.g., IL-12) in vitro and in vivo and epithelial damage in vivo. TLR4 signaling is required for peroxisome proliferator-activated receptor gamma expression, a DNA-binding protein that induces AA-M phi genes, whereas IFN-beta regulates IL-4, IL-13, IL-4R alpha, and IL-10 expression in response to RSV. RSV-infected cotton rats treated with a cyclooxygenase-2 inhibitor increased expression of lung AA-M phi. These data suggest new treatment strategies for RSV that promote AA-M phi differentiation.