bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of CCR2+ Myeloid Cells in Pulmonary Inflammation Responses Driven by Expression of a Surfactant Protein-C Mutant in the Alveolar Epithelium
Authors: Venosa Alessandro , Cowman Sophie , Tomer Yaniv , Katzen Jeremy , Armstrong Brittnie , Beers Michael 
Published: February 2023

Abstract
Acute inflammatory exacerbations (AIE) represent precipitous deteriorations of a number of chronic lung conditions, including pulmonary fibrosis (PF), COPD, and asthma. AIEs are marked by diffuse and persistent polycellular alveolitis that profoundly accelerate lung function decline and mortality. Excess monocyte mobilization during AIE and their persistence in the lung are linked to poor disease outcome. Guided by clinical evidence, we have developed a mutant model of pulmonary fibrosis leveraging the PF-linked missense isoleucine to threonine substitution at position 73 [I73T] in the alveolar type-2 cell-restricted Surfactant Protein-C [SP-C] gene [SFTPC]. With this toolbox at hand, the present work investigates the role of resident alveolar macrophages and peripheral monocytes during the initiation and progression of AIE-PF. Genetic ablation of CCR2+ monocytes (SP-C I73TCCR2KO) resulted in improved lung histology, mouse survival, and reduced inflammation compared to SP-C I73TCCR2WT cohorts FACS analysis of SigF+CD11b− alveolar macrophages and Ly6Chi monocytes isolated 3 d and 14 d after SP-CI73T induced injury reveals dynamic transcriptional changes associated with “Innate Immunity’ and ‘ECM Remodeling” signaling. In situ hybridization analysis revealed comparable levels of tgfb1 mRNA expression localized primarily in parenchymal cells in parenchymal cells found nearby foci of injury. We also observed partial tgfb1 mRNA colocalization in iNOS+ and Arg1+ activated cells in SP-CI73TCCR2WT mice, but not in SP-CI73TCCR2KO lungs. Together, these results provide a detailed picture on the role of resident macrophages and recruited monocytes in the context of AIE-PF driven by alveolar epithelial dysfunction.
RNF5-deficiency inhibits CD8+ T cell exhaustion in chronic antigen stimulation
Authors: Bae Eun-ah , Hope Jennifer L , Otero Dennis C , Faso Hannah A , Palete Ashley B , Ronai Ze’ev A , Bradley Linda M 
Published: February 2023

Abstract
Functional T cell exhaustion develops with persistent antigen exposure during chronic viral infection and cancer. Greater insights into T cell exhaustion are needed to promote immunity to viruses and tumors. RNF5 (RING-finger protein 5) is an E3 ubiquitin ligase that functions in protein degradation. We previously found enhanced anti-tumor responses in RNF5−/− mice, which was coupled with greater recovery and function of CD8+ T cell in melanoma tumors. Tumor-infiltrating RNF5−/− CD8+ T cells expressed high levels of inhibitory receptors (IR), yet greater functionality compared to WT CD8+ T cells, suggesting greater activation. To further assess RNF5-dependent regulation of CD8+ T cell exhaustion, we used the chronic LCMV Cl13 infection that has defined states of progressive T cell exhaustion. Virus-specific CD8+ T cells were significantly increased in RNF5−/− mice leading to greater numbers of cytokine producers, which expressed high levels of IRs. They also expressed higher levels of TOX, a transcriptional regulator of T cell exhaustion and persistence. With low dose infection, RNF5−/− mice displayed decreased morbidity and CD8+ T cells acquired a highly functional memory phenotype rather than exhaustion. To identify T cell intrinsic role(s) of RNF5, we analyzed anti-viral responses in bone marrow chimeras lacking RNF5 only in T cells and used an in vitro T cell exhaustion assay. RNF5−/− CD8+ T cells also expressed high levels of IRs and TOX, as did the in vitro exhausted T cells yet importantly displayed enhanced cytokine production compared to WT cells. These data reveal a T cell-intrinsic role of RNF5 in promoting exhaustion in settings of chronic antigen stimulation.
DNA-PK senses DNA virus infection in human cells
Authors: Ferguson Brian J , Hristova Dayana , Oliveira Marisa , Wagner Emma 
Published: February 2023

Abstract
The type I interferon (IFN-I) response to virus infection is initiated by the detection of nucleic acids by intracellular pattern recognition receptors (PRRs). The sensing of DNA viruses by PRRs is carried out by a number of DNA-binding PRRs that signal via the adaptor protein stimulator of interferon genes (STING) to drive IFN-I transcription. We previously described the role of DNA-dependent protein kinase (DNA-PK) as a viral DNA sensor in murine fibroblasts. In this study we show that DNA-PK is essential for the host response to DNA and DNA viruses in human fibroblasts. In the absensce of the catalytic subunit of the DNA-PK heterotrimer, DNA-PKcs, fibroblasts are deficient in their ability to activate a IFN-I response to DNA. DNA-PKcs is activated rapidly following exogenous DNA transfection or DNA virus infection and is required for signalling via STING and the kinase TBK-1 to the transcription factor interferon regulator factor 3 (IRF-3). Most wild-type DNA viruses combat intracellular DNA PRRs using immunomodulatory proteins encoded in their genomes and are effective at blocking IFN-I responses in infected cells. Here we make use of attenutated vaccina and herpes simplex 1 viruses that are lacking the immunomodulators that target DNA sesining mechanisms. We show that DNA-PKcs can sense these viruses and is required for triggering the IFN-I response in infected cells. These data cement the role of DNA-PK in the sensing of DNA virus infections in human cells.
Contribution of the NADase function of bacterial TIR domain proteins to the inhibition of innate immune responses
Authors: Palm Cheyenne , Scudder Alexis , Schmidt Katrina , Harberts Erin M , Snyder Greg A , Snyder Michelle 
Published: February 2023

Abstract
Pathogenic microbes have evolved various mechanisms to evade recognition by host immune responses, which can lead to the prevalence of disease and infection. Many strains of pathogenic bacteria contain genes encoding Toll/Interleukin-1 receptor (TIR) domain-containing proteins that function through the inhibition of TLR and myeloid differentiation factor 88 (MyD88) signaling. Previous research has also revealed that prokaryotic TIR domains may regulate bacterial and host metabolic pathways by acting as NAD+ glycohydrolases (NADases). We hypothesize that this NADase activity may contribute to the role of bacterial TIRs as virulence factors. In order to test this hypothesis, we observed the effects of TIR NADase activity on the binding interactions between bacterial TIRs and host MyD88, and on the ability of bacterial TIRs to block NF-kB signaling. For this, we have identified amino acids predicted to play a role in TIR NADase activity and have expressed and purified recombinant bacterial TIR proteins that have incorporated these mutations. We then tested the NADase activity of these mutants in comparison with that of wild-type TIR proteins and TIRs with mutations already known to inhibit NADase activity. We are now using mutant TIRs with deficiencies in NADase activity in pull-down assays to test their binding to MyD88 and utilizing reporter assays to analyze the effects of these mutant TIRs on NF-kB signaling. This information will allow us to gain a deeper understanding into the relationship between NADase activity in bacterial TIRs and their virulence activity, and can potentially uncover new mechanisms for pathogenic evasion of host immune defenses.
Phosphorylation and Chromatin Tethering Prevent cGAS activation During Mitosis
Authors: Li Tuo , Huang Tuozhi , Chen Zhijian J 
Published: February 2023

Abstract
The cyclic GMP-AMP synthase (cGAS) detects microbial and self-DNA in the cytosol to activate immune and inflammatory programs. cGAS also associates with chromatin especially after nuclear envelop breakdown when cells enter mitosis. How cGAS is regulated during cell cycle transition is not clear. In this presentation, we will provide direct biochemical data showing that cGAS activity is selectively suppressed during mitosis, and we report two parallel mechanisms underlying this suppression. First, we discovered that cGAS is hyperphosphorylated at the N-terminus by mitotic kinases, including Aurora kinase B. We show that the N-terminus of cGAS is critical for sensing nuclear chromatin, but not mitochondrial DNA and that chromatin sensing is blocked by hyperphosphorylation. Second, we demonstrate that chromatin-bound cGAS is prevented from oligomerization, which is required for its activation. Together, these mechanisms ensure that cGAS is inactive when associated with chromatin during mitosis to prevent autoimmune reaction.
B-Cell Responses in the Lung during Acute Pneumocystis Infection
Authors: Noell Kristin M , Kolls Jay K 
Published: February 2023

Abstract
Pneumocystis jiroveci is an opportunistic fungal organism that causes Pneumocystis pneumonia in humans with HIV-AIDS or in other immunocompromised individuals. A unique aspect of Pneumocystis is although it is associated with T cell immunodeficiency, recent evidence shows that B cells play a key role as antigen presenting cells in the lung to prime fungal T cell responses (Lund et.al, 2006; Lund et.al, 2003; and Opata et.al, 2015). Our lab has used the murine model of Pneumocystis as many mutations that predispose to Pneumocystis infections in humans replicate in this model (Elsegeiny et al. 2018). In contrast to other infections where dendritic cells are critical antigen presentation cells (APCs), it has been shown that in the context of Pneumocystis, B cells are the key APCs. Our lab has previously shown that IgM−/− mice have delayed CD4+ T cell priming as well as delayed fungal clearance. Therefore we hypothesize that germline encoded B cells react to specific Pneumocystis antigens, and that these B cells are critical to prime Pneumocystis specific CD4+ T cells. We have found that both C57BI/6 and Aicda−/− mice have anti-Pneumocystis IgM prior to infection. Moreover, we found anti-Pneumocystis antibodies in human cord blood and using proteomics we have identified that cord blood pulled down several antigens including PNEG_01454. In the murine model, we found that IgM reacts with a fungal protein involved in ascospore assembly, Meu10. Additionally, using recombinant Meu10 we found Meu10 specific IgM B cells in spleen by Elispot. Current studies are assessing if Meu10 is a T cell epitope and whether Meu10 specific B cells facilitate T cell mediated clearance of the fungus in vivo.
IL-12p40 and Type 1 immunity are induced by Toxoplasma gondii in the absence of the TLR-MyD88 signaling cascade
Authors: Snyder Lindsay , Doherty Claire M. , Mercer Heather L. , Denkers Eric Y. 
Published: February 2023

Abstract
Toxoplasma gondii is an orally acquired pathogen that induces strong, protective IFN-γ based immunity. The response in mice is driven in part by well-characterized MyD88-dependent signaling pathways. The objective of this study was to determine the induction of immune responses that do not involve this Toll-like receptor (TLR)/IL-1 family receptor adaptor molecule, with particular focus on events in the intestinal mucosa. Using eYFP-IL-12p40 reporter mice on an MyD88−/− background, we identified dendritic cells, macrophages, and neutrophils as cellular sources of MyD88-independent IL-12 after peroral T. gondii infection. While infection-induced IL-12 was lower in the absence of MyD88, the cytokine was nonetheless required to induce type I immunity. Type 1 and type 3 innate lymphoid cells (ILC), CD4+ T cells, and CD8+ T cells each contributed to the IFN-γ pool. Furthermore, bacterial flagellin and Toxoplasma specific CD4+T cell populations in the lamina propria expanded to similar frequencies observed in the wildtype small intestine. ILC3 were expanded in both naïve and infected MyD88−/− mice relative to their MyD88+/+ counterparts, suggesting a compensatory response triggered by loss of MyD88. This study identifies MyD88-independent intestinal immune pathways induced by T. gondii including myeloid cell derived IL-12 production, downstream type I immunity, and IFN-γ production by ILC1, ILC3, and T lymphocytes. Collectively, these data reveal an underlying network of immune responses that do not involve MyD88 but that contribute to pathways associated with resistance to T. gondii.
MALNUTRITION IMPACTS PROTECTIVE IMMUNE RESPONSES AND MUCOSAL IMMUNITY DURING VISCERAL LEISHMANIASIS
Authors: Sacramento Laís Amorim , Lombana Cláudia , Scott Phillip 
Published: February 2023

Abstract
Protein malnutrition is a risk factor for developing visceral leishmaniasis (VL) due to defective immune responses that culminate in early visceralization. The intestine is a target of both malnutrition and infection, but the immunological events that occur there during infection are unknown. We postulated that malnutrition exacerbates VL due to defective immunological mechanisms to control parasite replication in the spleen and liver, and by modifying intestinal mucosal immunity. To study the effect of malnutrition on immune response in chronic VL we used a polynutrient deficiency (deficient protein, energy, zinc, and iron) diet which mimics moderate human malnutrition followed by Leishmania infantum infection. The polynutrient deficient diet leads to growth stunting, reduced mass, and cellularity of the spleen, liver, and mesenteric lymph node (MLN). Malnourished-infected mice were more susceptible to infection, harboring more parasites in the spleen and liver. Flow cytometry analysis revealed a reduced number of T lymphocytes, and reduced production of IFN-γ by T cells in malnourished-infected mice. In the MLN, L. infantum infection induced the production of IFN-γ and TNF, while malnourished-infected mice exhibited a significant decrease in the IFN-γ production by T cells. Also, malnourished-infected mice presented a reduction in the IL-17 and IL-22 production by CD4+ cells, which are critical components for intestinal integrity and homeostasis. Together, malnutrition causes a defective IFN-γ-mediated response and promotes dysfunctional mucosal immunity which increases susceptibility in VL.
Nod2-deficient CD4+ T cells protect against Candida albicans infection
Authors: Lashley Sydney J , Lee Ellen J , Vance Emily E , Dugan Jae W , Philpott Dana J , Davey Michael P , Rosenzweig Holly L , Napier Ruth J 
Published: February 2023

Abstract
Nucleotide-binding oligomerization domain-containing protein 2 (Nod2) is a pattern recognition receptor known to promote anti-bacterial immunity yet its function in fungal disease is less understood. Here we sought to investigate the role of Nod2 in regulating fungal infection. Our results demonstrate that Nod2−/− mice infected with 105 (LD50) Candida albicans had increased survival and reduced kidney pathology compared to WT mice, indicating an important role for Nod2-deficiency in protection against infection. In corroboration, Nod2−/− mice had increased fungal clearance in the kidney within 24–72 h post-infection. T cell-deficient Rag−/− or Nod2−/− Rag−/− mice infected with C. albicans had similar fungal burdens, indicating a cellular role for Nod2 outside of innate and non-hematopoietic cells. In support, Nod2−/− mouse kidneys had increased frequencies of CD4+ T cells 48h post-infection, indicating a potential protective function for Nod2−/− T cells. To evaluate a putative T cell-intrinsic function of Nod2 we infected Rag1−/− mice reconstituted with CD4+ T cells from conditional knockout mice deficient in Nod2 in CD4+ T cells (Nod2fl/fl/CD4-cre) or control mice (CD4-cre). Mice harboring CD4+ T cells from Nod2fl/fl/CD4-cre mice had decreased fungal burden within 48 h and increased Th17 cells in the kidneys akin to the global Nod2−/− mice. Protection conferred by Nod2-deficient CD4+ T cells was abrogated by neutralization of IL-17, indicating the functional importance of the Nod2/IL-17 response in CD4+ T cells in C. albicans pathogenesis. Cumulatively, our data suggest that in opposition to the known protective role of Nod2 in bacterial infections, T cell-intrinsic Nod2 promotes fungal infection.
Airway bacteria prime innate immune protection against Streptococcus pneumoniae
Authors: Clark Sarah E , Schopper Melissa , Horn Kadi 
Published: February 2023

Abstract
Commensal (non-pathogenic) bacteria play an important role in protecting against disease. In both humans and animal models, the depletion of commensal bacteria by antibiotics increases susceptibility to pathogen infection of the lung. However, the specific commensal bacteria which contribute to this protective effect remain undefined. In the respiratory tract, Prevotella species are frequently associated with health rather than disease, indicating a potentially beneficial role. Specifically, some Prevotella species negatively correlate with infection with the bacterial pathogen Streptococcus pneumoniae, the most common cause of bacterial pneumonia. We recapitulated this relationship in mice, where we find that exposure to an airway commensal Prevotella species improves rapid clearance of S. pneumoniae from the lung. The use of heat-killed Prevotella was sufficient for inducing protection against S. pneumoniae, which was lost in mice depleted of the pro-inflammatory cytokine TNF-α. These results suggest that Prevotella exposure primes an immune response that increases protection against S. pneumoniae infection in the lung. We further find that mouse neutrophils both secrete TNF-α and are improved in their ability to kill S. pneumoniae following Prevotella exposure. Together, these findings indicate that airway Prevotella species can enhance protection against S. pneumoniae lung infection by activating an innate immune response that increases bacterial clearance.
Colitis alters the antigen-specific response to skin commensal bacteria and predisposes to neutrophilic skin inflammation
Authors: Merana Geil Ramvielle , Dhariwala Miqdad , Dwyer Laura , Scharschmidt Tiffany 
Published: February 2023

Abstract
Both gut and skin house microbial communities capable of influencing host immunity. During homeostasis, resident microbes are thought to have a dominant impact on local immune cell function. However, the prevalence of skin disorders among IBD patients suggests that this compartmentalized control may not hold under disease conditions. We hypothesize that an altered immune response to gut-resident microbes during colitis may facilitate excessive inflammation directed at skin commensals. Our lab has previously shown that colonization of neonatal mice with Staphylococcus epidermidis expressing the model antigen 2W (S. epi-2W) results in establishment of tolerance, as denoted by a higher percentage of 2W-specific regulatory T cells (Tregs) in the skin and skin-draining lymph nodes (SDLNs) and fewer skin neutrophils upon later-life S. epi-2W re-exposure. To test whether colitis perturbs tolerance to commensal skin bacteria, we colonized mice with S. epi-2W as neonates and subjected them to colitis as adults in conjunction with re-exposure. Colitic mice exhibited increased skin neutrophils and reduced percentages of S. epi-specific Tregs in skin and SDLNs compared to controls. Notably, no difference in S. epi-specific Tregs was noted in mice subjected to LPS-induced sepsis. Increased intra-intestinal presence of S. epi-2W during colitis indicates initiation of this response in the gut. Consistent with this, adoptive transfer experiments revealed a colitis-induced increase in CD4+ T cell trafficking from gut-draining LN to SDLNs. Recovery of S. epi-specific Tregs in colitic Cd4CreIl1r1flox/flox mice indicates an additional role for circulating IL-1 cytokines in shaping the skin commensal response during colitis.
AhR expression on both Rorc-specific immune cells and Vil1-expressing colonic epithelial cells are essential for I3C-mediated protection against colitis
Authors: Mitchell Chandani , Staley Shanieka , Wilson Keisha , Rutkovsky Alex , Wisniewski Pj , Dopkins Nicholas , Nagarkatti Mitzi , Nagarkatti Prakash , Busbee Philip B 
Published: February 2023

Abstract
Colitis is an inflammatory bowel disease (IBD) characterized by dysregulation of the immune system. In our previous reports, we showed indole-3-carbinol (I3C), an aryl hydrocarbon receptor (AhR) ligand, was able to reduce colitis-induced disease severity in an interleukin-22 (IL-22) dependent manner, mainly though innate lymphoid type 3 (ILC3) cells. In the current study, we generated cell-specific conditional knockout (KO) mice that had AhR deficiency in either Rorc-expressing immune cells (ILC3s), or Vil1-expressing colonic epithelial cells (CECs). We induced colitis using the dextran sodium sulfate (DSS) model in control mice and conditional KO strains, those deficient of AhR in Rorc (AR mice) or Vil1 (AV mice) cells. Results showed that compared to control mice, both AR and AV mice lost the expected efficacy effects of I3C treatment during colitis, with higher disease score and inflammation in the colon. Interestingly, immune cell profiling by single-cell RNAseq and flow cytometry showed only AR mice lost the ability to increase IL-22 secretion by ILC3s after I3C treatment during colitis. Since AV mice were still able to increase IL-22 via ILC3s, this suggests AhR deficiency in the CECs leads to alterations in other I3C-mediated mechanisms used to prevent colitis development, independent of the IL22-ILC3 axis. Collectively these data show AhR expression in both specific immune cells and CECs play a pivotal role in I3C-mediated prevention of colitis, though their mechanisms differ.
Altered levels of immune checkpoint molecules in colon biopsies and sera from microscopic colitis and ulcerative colitis patients compared to controls
Authors: Lushnikova Alexandra , Sjöberg Klas , Münch Andreas , Lange Anna , Bohr Johan , Hultgren Olof , Hörnquist Elisabeth Hultgren 
Published: February 2023

Abstract

Background:
Microscopic colitis (MC), comprising lymphocytic colitis (LC) and collagenous colitis (CC), is an inflammatory bowel disorder. MC patients have a lower risk of developing colorectal cancer (CRC) than ulcerative colitis (UC) patients. We hypothesize that the immune response in MC is geared more towards immune surveillance of tumor cells than that of UC, which instead contributes to inflammation-associated CRC.

Methods:
Using Luminex, protein levels of 14 immune checkpoints (TIM-3, CD28, CD137, CD27, CD152, HVEM, IDO, LAG-3, BTLA, GITR, CD80, PD-1, PD-L1, PD-L2) in protein lysates from colon biopsies (controls, n = 9; diarrhea controls, n = 7; LC, n = 14; CC, n = 15; UC, n = 17) were analyzed. Soluble checkpoints were analyzed in serum (23 controls, 17 LC, 36 CC and 2 UC).

Results:
In patients with active LC and CC, CD137, IDO, and CD80 levels were increased compared with one or both control groups. CD152 and PD-1 levels were increased in patients with active CC compared with both control groups. In patients with active UC, levels of CD137, CD152, BTLA, PD-1, and PD-L2 were increased compared with both control groups, IDO levels were increased compared with controls, and CD80 levels were raised compared with diarrhea controls.
In sera, CD27, IDO, CD80, PD-1, and PD-L2 levels were decreased in LC patients compared to controls.

Conclusions:
Increased levels of immune checkpoint molecules in colon biopsies from UC and MC patients are likely a sign of inflammation and may indicate what kind of homeostatic feed-back mechanisms are active to balance inflammation. Lowered concentrations of soluble immune checkpoint molecules in sera from patients with LC indicate a different level of homeostatic balance systemically in LC patients versus controls.