bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nod1 deficiency inhibits autophagy against Salmonella typhimurium in macrophages (136.21)
Authors: Anand Paras , Kanneganti Thirumala-Devi 
Published: January 2023

Abstract
Autophagy is a conserved bulk-degradation process involving double-membraned structures called autophagosomes that degrade damaged organelles. Recently, it has been reported that autophagy is important in immunity to microbial pathogens whereby intracellular bacteria are targeted for clearance by autophagy. However, the exact mechanism of how these microbes are identified by autophagy within host cells is still not clear. Innate immune cells rely on pathogen recognition receptors such as nucleotide-binding oligomerization-domain (NOD) like receptor (NLR) family to mount an appropriate immune response against pathogens. The NLR proteins Nod1 and Nod2 were shown to be important for bacterial clearance in dendritic cells. In this context, we found that Nod1 regulates autophagy in macrophages infected with Salmonella typhimurium . Infection of wild-type bone marrow-derived macrophages with Salmonella increased LC3-I lipidation to LC3-II as observed by Western blot. However, Nod1 deficient macrophages showed reduced LC3-II expression and thus autophagy. There were fewer cells with LC3-GFP autophagomes in macrophages deficient for Nod1 as compared to infected wild-type macrophages. Activation of Nod1 and Nod2 initiates a pro-inflammatory response by NF-kB pathway through the recruitment of adaptor protein RICK. We found a similar result in RICK deficient macrophages infected with Salmonella . Our results show a potential role for Nod1 in antibacterial autophagy activation.
Reprogramming of TLR4 signaling in endotoxin tolerance: altered IRAK4 and TAK1 activation, K63-linked polyubiquitination and signalosome assembly of IRAK1, TRAF6, IKKγ and increased A20 expression (136.23)
Authors: Xiong Yanbao , Qiu Fu , Piao Wenji , Song Chang , Wahl Larry M , Medvedev Andrei E 
Published: January 2023

Abstract
Prior exposure to LPS induces endotoxin tolerance that impairs TLR4-elicited pro-inflammatory cytokines without inhibiting anti-inflammatory or anti-microbial mediators, and is important for pathogenesis of the anti-inflammatory response syndrome and secondary infections in septic patients. The impact of endotoxin tolerance on the earliest TLR4 signaling events is largely unknown. We report that endotoxin tolerization impairs LPS-mediated activation of IRAK4 and TAK1 in human monocytes and THP1 cells. Overexpression of wild-type and mutant ubiquitin variants and the use of antibodies discriminating K48- vs. K63-linked polyubiquitin chains revealed that endotoxin tolerization compromises LPS-induced K63-linked, but not K48-linked polyubiquitination of IRAK1 and TRAF6. Diminished K63-linked polyubiquitination of IRAK1 and TRAF6 correlated with compromised LPS-inducible IRAK1-TRAF6 and IRAK1-IKKγ complex assemblies observed in endotoxin-tolerant cells. Alterations in these proximal signaling events manifested by LPS-tolerant cells correlated with increased expression of A20, an essential de-ubiquitination enzyme that targets TRAF6 to remove K63-linked polyubiquitin chains. Thus, deficiencies in LPS-induced activation of IRAK4 and TAK1, K63-linked polyubiquitination of IRAK1 and TRAF6 and IRAK1-TRAF6 and IRAK1-IKKγ assembly associated with increased expression of A20 represent new critical molecular determinants of endotoxin tolerance.
The role of TLR3 in protection of diabetes by PolyI:C in NOD mice (136.31)
Authors: Xiang Yufei , Wen Li , Zhou Zhiguang , Wong F. Susan 
Published: January 2023

Abstract
We aim at dissecting the timing and the role of TLR3 in the PolyI:C protective effect in NOD mice using adoptive transfer models. Irradiated young WT or TLR3-/- NOD mice were used as recipients. We treated the recipients with PolyI:C before or after adoptive transfer. Splenocytes from diabetic wild type or TLR3-/- NOD mice were transferred into non-diabetic, young WT or TLR3-/- NOD recipients in a criss-cross approach. Our results showed that treatment with PolyI:C either before or after adoptive transfer in the NODàNOD system significantly protected from diabetes development (p=0.022).This is particularly evident in treatment after adoptive transfer. Interestingly, in the NOD to TLR3-/- system, treatment with Poly I:C after adoptive transfer accelerated diabetes development. In the TLR3-/- to NOD groups PolyI:C administration again showed a protective effect and it appears that treatment with Poly I:C before adoptive transfer had a better protective effect (p=0.047).Finally, to further differentiate the role of TLR3 in hematopoietic from non-hematopoietic cells, we performed bone marrow chimera experiments without any exogenous treatment. Interestingly, the onset of diabetes was faster and the overall disease development was also higher in NOD to TLR3-/- chimeras (p=0.04). In summary, our results suggest that the Poly I: C protective effect is likely to be time dependent and expression of TLR3 in non-hematopoietic cells may be important in diabetes development.
Papillomavirus virus-like particles trigger IL-1beta release through the canonical inflammasome activation signaling pathway (136.33)
Authors: Zhong Zhenyu , Zhai Yougang , Qiao Liang 
Published: January 2023

Abstract
Papillomavirus virus-like particles (VLPs), formed by self-assembled caspid L1 protein, are extremely immunogenic. They can be used both as a mucosal delivery vector and an adjuvant for treating human diseases. However, the mechanism(s) by which papillomavirus VLPs function as an adjuvant is still unclear. We hypothesized that papillomavirus VLPs activate inflammasome in antigen-presenting cells to function as an adjuvant. In order to test our hypothesis, we cocultured HPV16, BPV-1 VLPs or a BPV-1 VLP presenting HIV-1 gp41 neutralizing epitope (chimeric HIV-BPV VLPs) respectively with PMA-primed human THP-1 cells and determined IL-1beta release in the presence or absence of inhibitors of the Nlrp3-inflammasome pathway. We found that HPV-16, BPV-1 VLPs and chimeric HIV-BPV VLPs are capable of activating inflammasome in PMA-primed THP-1 cells, which eventually results in the release of IL-1beta. The release of IL-1beta by the VLPs requires the uptake of VLPs by macrophages as inhibition of clathrin-mediated endocytosis blocked IL-1beta release. Furthermore, the inhibition of cathepsin B or caspase-1 abolished IL-1beta release in the presence of the VLPs. Finally, we also found that generation of reactive oxygen species (ROS) is necessary for activating inflammsome since inhibition of ROS production reduced the level of released IL-1beta. Thus, our results demonstrated that papillomavirus VLPs can activate inflammasome through the canonical inflammasome activation pathway.
BK channel controls the TLR-induced pro-inflammatory activation of macrophages via IκBα/NFκB and p38 MAPK signaling. (136.35)
Authors: Dolganiuc Angela , Nelson Oranmiyan 
Published: January 2023

Abstract
Background: Macrophages (Mf) are key in innate immunity and inflammation. Toll-like receptors (TLR) sense bacterial-derived products and trigger the inflammation. Big-conductance (BK) channels contribute to cell repolarization and participate in signal transduction. The role of BKs in innate immunity is largely unknown. Methods: We stimulated RAW246.7 Mf with ligands of pro-inflammatory TLRs (TLR2-PGN, TLR4-LPS or TLR7/8-R848)± BK blocker iberiotoxin or opener NS1619 and analyzed RNA by PCR, protein by ELISA and western blot, DNA-binding by EMSA. Results: TLRs augmented BK RNA and protein levels. Chemical BK block inhibited Mf activation via TLR2, TLR4 and TLR7/8, indicated by reduced production of TNFα, IL-1, IL-6, IL-8 at the levels of both RNA and secreted protein. The inhibitory effect of BK block was time- and dose-dependent and was specific to stimulation with TLR ligands (not observed upon Mf stimulation with TNFα). Upstream in signaling, BK block prevented TLR-induced activation of the transcription factor NFκB in an IκBα-dependent manner. Further, BK block prevented MAPK p38 phosphorylation but spared activation of ERK. In contrast BK opener augmented LPS-induced NFkB activation and TNFα production with minimal effect of MAPK; its effect on TLR2- and TLR7/8-induced Mf activation was minimal. In conclusion, we identified that BK channels are key for TLR-induced pro-inflammatory activation of macrophages and could be useful for the control of TLR/Mf function.
Monophosphate Lipid A's TRIF-biased TLR4 signaling results in weak NLRP3 inflammasome priming and reduced IL1beta production, leading to decreased inflammation in vivo compared to Lipid A. (136.38)
Authors: Eaves Chelsea , Franchi Luigi , Roy Eron , Nunez Gabriel , Mitchell Thomas 
Published: January 2023

Abstract
Monophosphate Lipid A (MLA), a PAMP variant of the Lipid A moiety from LPS, exhibits 100-fold reduced toxicity than its parent molecule. We previously characterized MLA as TRIF-biased agonists of TLR4, meaning that while inductions of TRIF-dependent transcripts are comparable to Lipid A, MyD88-dependent transcripts are greatly reduced. Previous studies showed that MLA fails to induce IL1beta production from monocytic cell culture, and it was suggested that the lack of production of this pro-inflammatory cytokine could be responsible for MLA’s reduced toxicity. Our initial goal was to reconcile TRIF-biased TLR4 signaling and IL1beta loss with MLA’s reduced induction of inflammatory mediators. We find that MLA’s TRIF-biased TLR4 signaling leads to weak NLRP3 inflammasome priming and reduced IL1beta production from murine bone marrow derived dendritic cells. Comparison of inflammatory transcripts from spleen and liver of MLA and Lipid A treated WT or IL1RImutant mice suggests that IL1beta plays a critical role in the toxicity of Lipid A in vivo. We propose that TRIF-biased TLR4 signaling by MLA results in weak inflammasome priming, reduced IL1beta production and decreased induction of inflammatory mediators in vivo.
The Heat Shock Protein gp96 play a multifaceted role in regulating Toll-like receptor 9 (136.40)
Authors: Leifer Cynthia , Brooks James , Cameron Jody , Chiosis Gabriela 
Published: January 2023

Abstract
Inappropriate activation and failure to inactivate Toll-like receptors (TLRs) contribute to immune mediated pathology. Nucleic acid sensing TLRs, including TLR9, are tightly regulated to prevent self DNA and RNA recognition, which can contribute to autoimmune disease. The overall goal of our research is to determine the molecular mechanisms governing nucleic acid sensing TLRs using TLR9 as a model. Regulation of TLR9 includes control of intracellular trafficking by association with proteins such as the endoplasmic reticulum chaperone gp96. Obligate proteolytic cleavage of TLR9 to an 80 kDa form, p80, precedes TLR9 recognition of CpG DNA. Here we show that in the absence of gp96, there is a failure to generate p80. Furthermore, gp96 traffics with TLR9 to the endosomal compartment. Dissociation of gp96 from TLR9 using specific inhibitors leads to rapid degradation of the receptor and inhibition of signaling. CpG DNA pull down experiments demonstrate that gp96 is associated with the ligand-bound form of the receptor suggesting it contributes to CpG DNA recognition. We provide a model where gp96 plays a multifaceted role in TLR9 biology. These studies have major implications for pharmacologically manipulating the levels of active and inhibitory forms of TLR9 and other nucleic acid sensing TLRs, which will likely uncover novel therapeutic interventions for autoimmune diseases. AI076588 and AI076588-S1 (CAL).
Identification of dTOR as a signaling component in the Drosophila immune response (136.41)
Authors: Duan Yukan , Powell Jonathan 
Published: January 2023

Abstract
We have previously demonstrated a critical role for the mammalian Target Of Rapamycin (mTOR) in regulating T effector and regulatory cell differentiation. In light of the fact that TOR is highly evolutionarily conserved, we hypothesized that this signaling pathway would play a role in Drosophila immune responses. In Drosophila the Toll pathway, which is characterized by the induction of drosomycin, is responsible for fighting fungal and gram positive infections while the immune deficiency (IMD) pathway, which is characterized by attacin induction, responds to gram negative infection. Drosophila S2 cells were transfected with either drosomycin or attacin reporter constructs and appropriately stimulated in the presence of rapamycin. For both signaling pathways, rapamycin inhibited lucierase induction in a dose dependent fashion. Alternatively, S2 cell phagocytosis of either E. coli or S. aureus which is not dependent on these pathways was not inhibited by rapamcyin. Furthermore, western blot analysis of LPS stimulated S2 cells demonstrated increased Drosophila TOR (dTOR) activity as measured by phoshorylation of S6K-1. Overall our data identifies dTOR as playing a heretofore unappreciated role in the Toll and IMD pathways in Drosophila. Dissecting the precise role of dTOR in Drosophila immunity should provide important insight into the downstream mechanisms by which mTOR directs adaptive immune responses.
IL-10- and PD-1-dependent regulation of CD8+ T cell effector function in an adenoviral murine model for liver tropic viral infection (137.12)
Authors: Dolina Joseph , Hahn Young 
Published: January 2023

Abstract
Immune responses to pathogens in the liver are uniquely characterized by a tolerogenic feature as a result of constant exposure to bacterial constituents and food-derived antigens. Little is known about the molecular basis of the immune regulation to persistent viral infection in the liver. In these studies, we employed a model comparing subcutaneous (SC) and intravenous (IV) adenovirus infection, which result in the trafficking of CD8+ T cells to the liver with effective or defective antiviral function, respectively. During IV infection, intrahepatic CD8+ T cells display an inability to produce proinflammatory cytokines and lyse targets. IV adenovirus infection distinctively results in local intrahepatic antigen presentation responsible for limiting the CD8+ T cell immune response. Importantly, CD8+ T cells mounted by the IV infection demonstrate drastic up-regulation of PD-1 on their surface and produce IL-10 at the peak of the CD8+ T cell response. In addition, IL-10 producers elevate PD-1 expression, and PD-L1 blockade attenuates CD8+ T cell IL-10 production but increases IFN-γ production. These results suggest that the PD-1 and IL-10 signaling pathways appear to be dependent on each other. Interestingly, IL-10-producing CD8+ T cells have also been found in the livers of patients harboring hepatitis C virus, implicating a common regulatory role for these cells in liver tropic viral infections.
Prolonged antigen presentation is required for optimal CD8+ T cell responses against malaria liver stage parasites (137.16)
Authors: Cockburn Ian , Chen Yun-Chi , Overstreet Michael , Lees Jason , Farber Donna , Zavala Fidel 
Published: January 2023

Abstract
Immunization with irradiated sporozoites is the most effective vaccination strategy against liver stages of malaria parasites, yet the mechanisms underpinning the success of this approach are unknown. Here we show that the complete development of CD8+ T cell responses requires prolonged antigen presentation. Using TCR transgenic cells specific for the malaria circumsporozoite protein, a leading vaccine candidate, we found that sporozoite antigen persists for over 8 weeks after immunization - a remarkable finding since irradiated sporozoites are incapable of replication and do not differentiate into liver stages. Persisting antigen was detected in lymphoid organs and depends on the presence of CD11c+ cells. Prolonged antigen presentation enhanced the magnitude of the CD8+ T cell response in a number of ways. Firstly, reducing the time primed CD8+ T cells were exposed to antigen in vivo severely reduced the final size of the developing memory population. Secondly fully developed memory cells expanded in previously immunized mice but not when transferred to naïve animals. Finally, persisting antigen was able to prime naïve cells, including recent thymic emigrants, to become functional effector cells capable of eliminating parasites in the liver. Together these data show that the optimal development of protective CD8+ T cell immunity against malaria liver stages is dependent upon the prolonged presentation of sporozoite antigen.
Galectin-1 reduces the severity of herpes simplex virus induced ocular immunopathological lesions (137.20)
Authors: Rajasagi Naveen , Reddy Pradeep , Suryawanshi Amol , Rouse Barry 
Published: January 2023

Abstract
Stromal keratitis (SK) is a chronic immunopathological lesion of the eye caused by herpes simplex virus-1 (HSV-1) infection and one of the most common causes of blindness in humans. The inflammatory lesions are primarily perpetuated by IFN-γ producing CD4+ T cells. Therefore, targeting activated CD4+ T cell subsets represents a potentially valuable form of therapy to reduce the severity of disease. Galectin-1, an endogenous lectin, was recently shown to suppress certain autoimmune disorders through the selective inhibition of T helper type1 (TH1) and interleukin-17 producing T helper cells (TH-17). In the present report, we determined if galectin-1 administration begun at different times after ocular infection with HSV could influence the severity of HSK lesions. Treatment with recombinant galectin-1 (rGal-1) significantly reduced the extent of angiogenesis and SK lesions that occurred. Treated mice had reduced numbers of inflammatory cells that included TH1 and TH-17 cells as well as neutrophils in the cornea. The mechanisms by which galectin-1 acts will be described. The many effects include apoptosis of effector CD4+ T cells, induction of regulatory T cells, increased production of anti-inflammatory cytokines and inhibitory effects on molecules involved in neovascularization and SK pathogenesis. Our findings are the first to show that rGal-1 treatment represents a useful approach to control lesion severity in a virally induced immunopathological disease.
IL-2 therapy synergizes with PD-L1 blockade to rescue exhausted CD8+ T cells during chronic viral infection (137.24)
Authors: West Erin , Ha Sang-Jun , Tan Wendy , Jin Hyun-Tak , Freeman Gordon , Smith Kendall , Ahmed Rafi 
Published: January 2023

Abstract
Blocking PD-1 signaling, by administering anti-PD-L1 or anti-PD-1 antibodies, has proven to be effective in partially restoring CD8+ T cell function during multiple chronic infection models. However since PD-L1 blockade does not completely rescue CD8+ T cell function, we have focused on finding treatments that synergize with PD-1 blockade. Our lab has previously shown that IL-2 administration can increase the frequency of LCMV-specific CD8+ T cells and decrease viral load. Using a chronic model of lymphocytic choriomeningitis virus (LCMV) we demonstrate that combined IL-2 administration and PD-L1 blockade induces massive increases in LCMV-specific CD8+ T cells and an increased ability to produce inflammatory cytokines to multiple epitopes, including subdominant epitopes, over PD-L1 blockade alone. Furthermore, combined treatment results in greater reduction of viral loads. Importantly, IL-7Rα (CD127), a marker of functional memory cells that is not seen on exhausted cells, even after anti-PD-L1 treatment, was up-regulated on a population of LCMV-specific CD8+ T cells after IL-2 or, even more drastically, after combined treatment. These results indicate that combined IL-2 and PD-1 blockade may prove a potential therapy for increasing CD8+ T cell responses and viral control in human chronic infections.
Regulatory T cell expression of herpes virus entry mediator (HVEM) following HSV-1 infection and its functional significance. (137.25)
Authors: Sharma Shalini , Sundararajan Aarthi , Mulik Sachin , Rouse Barry 
Published: January 2023

Abstract
In many infections especially those that are chronic, the outcome may be influenced by the activity of one or more types of regulatory T cells (Tregs), particularly those that express FOXP3. In many instances, for example the response that follows HSV infection, the majority of expanded Tregs are not antigen specific. In this report, we demonstrate one possible mechanism by which HSV-1 infection could act to signal and expand the Treg population. We show that HVEM, a tumor necrosis factor receptor superfamily member which interacts with the gD protein of HSV-1 to facilitate cell entrance, is expressed by FOXP3+ T cells and that engagement of HVEM by its ligand expands the Treg population. To demonstrate this, FOXP3-GFP knock in mice were infected with HSV kos and change in cell numbers of Tregs and their expression levels of HVEM were recorded in draining popliteal lymph node (DLN). Tregs expansion occured following HSV-1 infection, peaking at around day 8 compared to the peak numbers of CD8+T cells (day 5 p.i). Both FOXP3+ and FOXP3- CD4 T cells expressed HVEM in the resting state but Tregs upregulated HVEM reaching highest MFI at day 7 p.i. In-vitro stimulation of DLN cells with UV inactivated HSV kos, further up regulated HVEM on Tregs (possibly through gD) and down regulated on FOXP3_ cells suggesting a possibility that engaging this receptor with gD expressed by infected cells results in Treg activation and expansion which in turn modulates CD8+ effector responses.
Expression of CD35 on subsets of human peripheral CD8+ T-cells (138.18)
Authors: Reilly Brian , Ketron Summer , Hempstead Shannon , Atkinson John 
Published: January 2023

Abstract
There is now considerable evidence that CD8+ T cell reactions can promote or suppress autoreactivity. The type of response is not only dictated by the TCR but also by other cellular receptors. Also known, is that natural deficiencies of certain complement components are associated with autoimmune responses. The potential link between complement and CD8+ T-cells was explored by examining several subsets for the expression of the complement receptor CD35. Mononuclear cells were purified from the peripheral blood of ten donors and further enriched for CD8+ T-cells by either positive or negative selection using immunomagnetic beads, and analyzed for the presence of CD35 by flow cytometry. Upon inspection, 6-12% expressed CD35 and were negative for CD56. Of the CD35+ cells, approximately 65% were found in the naïve subset (CCR7+CD45RA+), 15% in the CD45RA effector memory subset (CCR7-CD45RA+), and 10% in the central memory (CCR7+CD45RA-) and effector memory (CCR7-CD45RA-) subsets. Next, using plate-bound antibodies against CD3 and CD35, in vitro activation experiments were done followed by analysis of several T-cell responses. The results showed a substantial increase in cytokine secretion and intracellular granzyme production with minimal effect on cellular proliferation, compared to TCR cross-linking alone. These data imply that the CD8+ T-cells, which express CD35, modulate T-cell responsiveness following co-engagement of the TCR and CD35.