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APC-PAR1-R46 signaling limits CXCL1 expression during poly IC-induced airway inflammation in mice. J Thromb Haemost 2023; 21:3279-3282. [PMID: 37634652 DOI: 10.1016/j.jtha.2023.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 08/29/2023]
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Abstract 474: Macrophage Par2 Contributes To Influenza A Virus Pathology And Is A Potential Therapeutic Target To Treat Influenza A Virus Infection. Arterioscler Thromb Vasc Biol 2022. [DOI: 10.1161/atvb.42.suppl_1.474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Proteinase-activated receptor 2 (PAR2) was shown to enhance proinflammatory toll-like receptor 3 (TLR3) responses, while dampening TLR3-dependent antiviral response in epithelial cells. Moreover,
Par2
-/-
mice exhibited improved survival after influenza A virus (IAV) infection. The objective of the study is to identify PAR2 expressing cells contributing to IAV pathology, and test if PAR2 inhibition is a potential new target to treat IAV. Infection with H1N1 IAV (PR8) was analyzed in global (
Par2
-/-
), myeloid (
Par2
fl/fl
;LysM
Cre+
), neutrophil (
Par2
fl/fl
;MRP8
Cre+
) and lung epithelial cell (EpC)
Par2
deficient (
Par2
fl/fl
;SPC
Cre+
) mice and respective controls (
Par2
+/+
and
Par2
fl/fl
). The effect of PAR2 activation on poly I:C activation of TLR3 was analyzed in bone marrow-derived macrophages (BMDM) and murine macrophage-like J774A.1 cells. Lastly, we analyzed PAR2 inhibition in wild-type (WT) mice using mouse-anti PAR2 antibody (SAM11) and small molecule PAR2 inhibitor ENMD-1068.
Par2
-/-
and
Par2
fl/fl
;LysM
Cre+
mice exhibited increased survival, reduced proinflammatory mediators and cellular infiltration in bronchoalveolar lavage fluid (BALF) 3 days post infection (dpi) compared to control mice. Reduced IAV pathology resulted in significantly better lung function (PenH, airway resistance) in
Par2
-/-
mice compared to
Par2
+/+
mice 7 dpi. Neither
Par2
fl/fl
;MRP8
Cre+
or
Par2
fl/fl
;SPC
Cre+
mice showed any survival benefit compared to
Par2
fl/fl
.
In vitro
studies showed that
Par2
-/-
BMDM produced less IL6 and IL12p40 than
Par2
+/+
BMDM after poly I:C stimulation. J774A.1 cells stimulated with PAR2 agonist and poly I:C showed an increase in NFκB activation compared to poly I:C alone. Prophylactic PAR2 inhibition with SAM11 before and daily after IAV infection, decreased BALF inflammation and lung virus load compared to control IgG treated mice 3dpi. Therapeutic PAR2 inhibition with ENMD-1068 daily from 3 dpi resulted in improved lung function (PenH) compared to vehicle treated mice 7 dpi. Global or macrophage cell but not neutrophil or lung EpC
Par2
deficiency was associated with reduced IAV-induced lung pathology and mortality. Additionally, PAR2 inhibition experiments showed PAR2 may be a therapeutic target to reduce IAV pathology.
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Myeloid Protease-Activated Receptor-2 Contributes to Influenza A Virus Pathology in Mice. Front Immunol 2021; 12:791017. [PMID: 34925374 PMCID: PMC8671937 DOI: 10.3389/fimmu.2021.791017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 11/12/2021] [Indexed: 11/13/2022] Open
Abstract
BackgroundInnate immune responses to influenza A virus (IAV) infection are initiated in part by toll-like receptor 3 (TLR3). TLR3-dependent signaling induces an antiviral immune response and an NFκB-dependent inflammatory response. Protease-activated receptor 2 (PAR2) inhibits the antiviral response and enhances the inflammatory response. PAR2 deficiency protected mice during IAV infection. However, the PAR2 expressing cell-types contributing to IAV pathology in mice and the mechanism by which PAR2 contributes to IAV infection is unknown.MethodsIAV infection was analyzed in global (Par2-/-), myeloid (Par2fl/fl;LysMCre+) and lung epithelial cell (EpC) Par2 deficient (Par2fl/fl;SPCCre+) mice and their respective controls (Par2+/+ and Par2fl/fl). In addition, the effect of PAR2 activation on polyinosinic-polycytidylic acid (poly I:C) activation of TLR3 was analyzed in bone marrow-derived macrophages (BMDM). Lastly, we determined the effect of PAR2 inhibition in wild-type (WT) mice.ResultsAfter IAV infection, Par2-/- and mice with myeloid Par2 deficiency exhibited increased survival compared to infected controls. The improved survival was associated with reduced proinflammatory mediators and reduced cellular infiltration in bronchoalveolar lavage fluid (BALF) of Par2-/- and Par2fl/fl;LysMCre+ 3 days post infection (dpi) compared to infected control mice. Interestingly, Par2fl/fl;SPCCre+ mice showed no survival benefit compared to Par2fl/fl. In vitro studies showed that Par2-/- BMDM produced less IL6 and IL12p40 than Par2+/+ BMDM after poly I:C stimulation. In addition, activation of PAR2 on Par2+/+ BMDM increased poly I:C induction of IL6 and IL12p40 compared to poly I:C stimulation alone. Importantly, PAR2 inhibition prior to IAV infection protect WT mice.ConclusionGlobal Par2 or myeloid cell but not lung EpC Par2 deficiency was associated with reduced BALF inflammatory markers and reduced IAV-induced mortality. Our study suggests that PAR2 may be a therapeutic target to reduce IAV pathology.
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