Innate immunity constitutes pro-inflammatory response to initiate inflammation for adaptive immune response required for virus clearance. Pro-inflammatory (and inflammation) response need to be ?tightly? regulated during virus infection since exaggerated inflammation contributes to inflammatory diseases. Activation of Pattern Recognition Receptors (PRRs) is critical for triggering innate immunity and inflammation during infection with human respiratory syncytial virus (RSV) and influenza A virus (IAV). Therefore, it is important to study the underlying cellular/molecular mechanism involved in transducing optimal innate immunity and inflammatory (and pro-inflammatory) response upon PRR activation. We have surprisingly identified a novel signaling network that is required for optimal pro-inflammatory response following PRR activation. Our preliminary result suggested that an oxysterol (a bioactive lipid) 25-hydroxycholesterol (25HC) play an important role in magnifying and intensifying pro-inflammatory response following activation of PRRs and during virus (RSV, IAV) infection. Surprisingly we observed interaction of 25HC with cell surface integrins and further preliminary studies suggested a possible mechanism. Mechanistically, we postulate that 25HC released from PRR activated (and virus infected) cells act as an extracellular soluble mediator to activate 25HC--- integrin (?5?1, ?V?3 integrins)---FAK (focal adhesion kinase)---NF?B pathway for optimal pro-inflammatory response. Thus, we envision that extracellular 25HC serve as a ?linker? (via autocrine/paracine mechanism) to bridge PRR pathway with integrin pathway for optimal pro-inflammatory response. We hypothesize that - a) extracellular 25HC links PRR pathway with integrin pathway; b) PRR---25HC---integrin---FAK---NF?B signaling network magnifies pro-inflammatory response and inflammation; and c) 25HC--- integrin---FAK signaling pathway contributes to exaggerated inflammation during RSV and IAV infection, thus leading to development of exacerbated airway diseases like pneumonia and bronchiolitis. In the current proposal we have selected a membrane bound PRR (i.e. toll-like receptor 3 or TLR3) and a cytosolic PRR (i.e. Nod2) along with two clinically important respiratory viruses (RSV, IAV) to elucidate the role of 25HC---integrin---FAK---NF?B pathway in promoting optimal and maximal pro-inflammatory response.
In aim -1 we will investigate interaction of 25HC with integrins leading to activation of integrin---FAK---NF?B pathway and subsequent pro- inflammatory response in macrophages.
In aim -2 we will examine the role of 25HC---integrin---FAK---NF?B pathway in triggering optimal pro-inflammatory response in macrophages following PRR (TLR3, Nod2) activation and virus (RSV, IAV) infection. Finally, in aim-3 we will utilize knockout mice to study physiological in vivo role of 25HC---integrin---FAK pathway during PRR (Nod2, TLR3) activation and virus (RSV, IAV) infection. Significance ?Our current proposal has wide implication in development of therapeutics against RSV, IAV and other pathogens that activate PRRs.

Public Health Relevance

Innate immunity and inflammation dictates pathogenesis, susceptibility and disease severity following infection with pathogens, including influenza A virus (IAV) and respiratory syncytial virus (RSV) that cause life- threatening respiratory tract diseases like pneumonia and bronchiolitis. In the current application we propose to characterize the cellular and molecular mechanism regulating innate immune response and inflammation during IAV and RSV infection. Knowledge derived from our proposed study will be instrumental for development of vaccine and therapeutics to combat IAV and RSV infection. 1

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI083387-07A1
Application #
9467208
Study Section
Innate Immunity and Inflammation Study Section (III)
Program Officer
Kim, Sonnie
Project Start
2010-06-01
Project End
2022-07-31
Budget Start
2018-08-09
Budget End
2019-07-31
Support Year
7
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Washington State University
Department
Veterinary Sciences
Type
Schools of Veterinary Medicine
DUNS #
041485301
City
Pullman
State
WA
Country
United States
Zip Code
99164
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Segovia, Jesus A; Chang, Te-Hung; Winter, Vicki T et al. (2018) NLRP3 Is a Critical Regulator of Inflammation and Innate Immune Cell Response during Mycoplasma pneumoniae Infection. Infect Immun 86:
Pokharel, Swechha M; Shil, Niraj K; Bose, Santanu (2016) Autophagy, TGF-?, and SMAD-2/3 Signaling Regulates Interferon-? Response in Respiratory Syncytial Virus Infected Macrophages. Front Cell Infect Microbiol 6:174
Tsai, Su-Yu; Segovia, Jesus A; Chang, Te-Hung et al. (2015) Regulation of TLR3 Activation by S100A9. J Immunol 195:4426-37
Segovia, Jesus A; Tsai, Su-Yu; Chang, Te-Hung et al. (2015) Nedd8 regulates inflammasome-dependent caspase-1 activation. Mol Cell Biol 35:582-97
Bose, Santanu; Segovia, Jesus A; Somarajan, Sudha R et al. (2014) ADP-ribosylation of NLRP3 by Mycoplasma pneumoniae CARDS toxin regulates inflammasome activity. MBio 5:
Thinwa, Josephine; Segovia, Jesus A; Bose, Santanu et al. (2014) Integrin-mediated first signal for inflammasome activation in intestinal epithelial cells. J Immunol 193:1373-82
Tsai, Su-Yu; Segovia, Jesus A; Chang, Te-Hung et al. (2014) DAMP molecule S100A9 acts as a molecular pattern to enhance inflammation during influenza A virus infection: role of DDX21-TRIF-TLR4-MyD88 pathway. PLoS Pathog 10:e1003848
Mgbemena, Victoria; Segovia, Jesus; Chang, Te-Hung et al. (2013) KLF6 and iNOS regulates apoptosis during respiratory syncytial virus infection. Cell Immunol 283:1-7
Chang, Te-Hung; Segovia, Jesus; Sabbah, Ahmed et al. (2012) Cholesterol-rich lipid rafts are required for release of infectious human respiratory syncytial virus particles. Virology 422:205-13

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