Life Sciences Commons^™

Pneumolysin Activates The Nlrp3 Inflammasome And Promotes Proinflammatory Cytokines Independently Of Tlr4, Edel A. Mcneela, Aine Burke, Daniel R. Neill, Cathy Baxter, Vitor E. Fernandes, Daniela Ferreira, Sarah Smeaton, Rana El-Rachkidy, Rachel M. Mcloughlin, Andres Mori, Barry Moran, Katherine A. Fitzgerald, Jurg Tschopp, Virginie Petrilli, Peter W. Andrew, Aras Kadioglu, Ed C. Lavelle

Katherine A. Fitzgerald

Pneumolysin (PLY) is a key Streptococcus pneumoniae virulence factor and potential candidate for inclusion in pneumococcal subunit vaccines. Dendritic cells (DC) play a key role in the initiation and instruction of adaptive immunity, but the effects of PLY on DC have not been widely investigated. Endotoxin-free PLY enhanced costimulatory molecule expression on DC but did not induce cytokine secretion. These effects have functional significance as adoptive transfer of DC exposed to PLY and antigen resulted in stronger antigen-specific T cell proliferation than transfer of DC exposed to antigen alone. PLY synergized with TLR agonists to enhance secretion of the proinflammatory …

Superior Immunogenicity Of Inactivated Whole Virus H5n1 Influenza Vaccine Is Primarily Controlled By Toll-Like Receptor Signalling, Felix Geeraedts, Nadege Goutagny, Veit Hornung, Martina Severa, Aalzen De Haan, Judity Pool, Jan Wilschut, Katherine A. Fitzgerald, Anke Huckriede

Katherine A. Fitzgerald

In the case of an influenza pandemic, the current global influenza vaccine production capacity will be unable to meet the demand for billions of vaccine doses. The ongoing threat of an H5N1 pandemic therefore urges the development of highly immunogenic, dose-sparing vaccine formulations. In unprimed individuals, inactivated whole virus (WIV) vaccines are more immunogenic and induce protective antibody responses at a lower antigen dose than other formulations like split virus (SV) or subunit (SU) vaccines. The reason for this discrepancy in immunogenicity is a long-standing enigma. Here, we show that stimulation of Toll-like receptors (TLRs) of the innate immune system, …

Nod2, Rip2 And Irf5 Play A Critical Role In The Type I Interferon Response To Mycobacterium Tuberculosis, Amit K. Pandey, Yibin Yang, Zhaozhao Jiang, Sarah M. Fortune, Francois Coulombe, Marcel A. Behr, Katherine A. Fitzgerald, Christopher M. Sassetti, Michelle A. Kelliher

Katherine A. Fitzgerald

While the recognition of microbial infection often occurs at the cell surface via Toll-like receptors, the cytosol of the cell is also under surveillance for microbial products that breach the cell membrane. An important outcome of cytosolic recognition is the induction of IFNalpha and IFNbeta, which are critical mediators of immunity against both bacteria and viruses. Like many intracellular pathogens, a significant fraction of the transcriptional response to Mycobacterium tuberculosis infection depends on these type I interferons, but the recognition pathways responsible remain elusive. In this work, we demonstrate that intraphagosomal M. tuberculosis stimulates the cytosolic Nod2 pathway that responds …

Myd88-Dependent Il-1 Receptor Signaling Is Essential For Gouty Inflammation Stimulated By Monosodium Urate Crystals, Chun-Jen Chen, Yan Shi, Arron Hearn, Katherine A. Fitzgerald, Douglas T. Golenbock, George W. Reed, Shizuo Akira, Kenneth L. Rock

Katherine A. Fitzgerald

While it is known that monosodium urate (MSU) crystals cause the disease gout, the mechanism by which these crystals stimulate this inflammatory condition has not been clear. Here we find that the Toll/IL-1R (TIR) signal transduction adaptor myeloid differentiation primary response protein 88 (MyD88) is required for acute gouty inflammation. In contrast, other TIR adaptor molecules, TIRAP/Mal, TRIF, and TRAM, are not required for this process. The MyD88-dependent TLR1, -2, -4, -6, -7, -9, and -11 and IL-18 receptor (IL-18R) are not essential for MSU-induced inflammation. Moreover, MSU does not stimulate HEK cells expressing TLR1-11 to activate NF-kappaB. In contrast, …

Functional Regulation Of Myd88-Activated Interferon Regulatory Factor 5 By K63-Linked Polyubiquitination, Mumtaz Yaseen Balkhi, Katherine A. Fitzgerald, Paula M. Pitha

Katherine A. Fitzgerald

Interferon regulatory factor 5 (IRF-5) plays an important role in the innate antiviral and inflammatory response. Specific IRF-5 haplotypes are associated with dysregulated expression of type I interferons and predisposition to autoimmune disorders. IRF-5 is activated by Toll-like receptor 7 (TLR7) and TLR9 via the MyD88 pathway, where it interacts with both MyD88 and the E3 ubiquitin ligase, TRAF6. To understand the role of these interactions in the regulation of IRF-5, we examined the role of ubiquitination and showed that IRF-5 is subjected to TRAF6-mediated K63-linked ubiquitination, which is important for IRF-5 nuclear translocation and target gene regulation. We show …

Detecting Microrna Activity From Gene Expression Data, Stephen F. Madden, Susan B. Carpenter, Ian B. Jeffery, Harry Bjorkbacka, Katherine A. Fitzgerald, Luke A. J. O'Neill, Desmond G. Higgins

Katherine A. Fitzgerald

BACKGROUND: MicroRNAs (miRNAs) are non-coding RNAs that regulate gene expression by binding to the messenger RNA (mRNA) of protein coding genes. They control gene expression by either inhibiting translation or inducing mRNA degradation. A number of computational techniques have been developed to identify the targets of miRNAs. In this study we used predicted miRNA-gene interactions to analyse mRNA gene expression microarray data to predict miRNAs associated with particular diseases or conditions.

RESULTS: Here we combine correspondence analysis, between group analysis and co-inertia analysis (CIA) to determine which miRNAs are associated with differences in gene expression levels in microarray data sets. …

Lps-Tlr4 Signaling To Irf-3/7 And Nf-Kappab Involves The Toll Adapters Tram And Trif, Katherine A. Fitzgerald, Daniel C. Rowe, Betsy J. Barnes, Daniel R. Caffrey, Alberto Visintin, Eicke Latz, Brian G. Monks, Paula M. Pitha, Douglas T. Golenbock

Katherine A. Fitzgerald

Toll-IL-1-resistance (TIR) domain-containing adaptor-inducing IFN-beta (TRIF)-related adaptor molecule (TRAM) is the fourth TIR domain-containing adaptor protein to be described that participates in Toll receptor signaling. Like TRIF, TRAM activates interferon regulatory factor (IRF)-3, IRF-7, and NF-kappaB-dependent signaling pathways. Toll-like receptor (TLR)3 and 4 activate these pathways to induce IFN-alpha/beta, regulated on activation, normal T cell expressed and secreted (RANTES), and gamma interferon-inducible protein 10 (IP-10) expression independently of the adaptor protein myeloid differentiation factor 88 (MyD88). Dominant negative and siRNA studies performed here demonstrate that TRIF functions downstream of both the TLR3 (dsRNA) and TLR4 (LPS) signaling pathways, whereas the …

The Induction Of Macrophage Gene Expression By Lps Predominantly Utilizes Myd88-Independent Signaling Cascades, Harry Bjorkbacka, Katherine A. Fitzgerald, Francois Huet, Xiaoman Li, James A. Gregory, Melinda Lee, Christine M. Ordija, Nicole E. Dowley, Douglas T. Golenbock, Mason W. Freeman

Katherine A. Fitzgerald

Myeloid differentiation protein-88 (MyD88) is a signal adaptor protein required for cytokine production following engagement of Toll-like receptors (TLRs) by their cognate ligands. Activation of both TLR-3 and TLR-4, however, can engage signaling events independent of MyD88 expression. The relative importance of these MyD88-dependent and -independent signaling pathways in the macrophage response to lipopolysaccharide (LPS) is unknown. Here we define these events using microarray expression profiling of LPS-stimulated macrophages taken from MyD88-null and wild-type mice. Of the 1,055 genes found to be LPS responsive, only 21.5% were dependent on MyD88 expression, with MyD88-independent genes constituting 74.7% of the genetic response. …