bluuebunny/crossref_metadata_2025_split huggingface dataset:
VEGFR1 blockade reduces Mycobacterium tuberculosis-induced pathology in immunocompromised mice
Authors: Herbath Melinda , Priyathilaka Thanthrige Thiunuwan , Fabry Zsuzsanna , Sandor Matyas 
Published: August 2023

Abstract
Mycobacterium tuberculosis (Mtb) is a major public health concern that caused 1.6 million deaths in 2021. New treatments are needed, especially in immunocompromised individuals, such as patients with HIV coinfection, who are severely impacted by the disease.
We have recently reported that blocking VEGFR1, a receptor that is present on monocytes and contributes to their recruitment to the sites of infection, limits Mtb-induced pathology in immunocompetent mice of both Mtb-resistant (C57BL/6J) and Mtb-supersusceptible (C3HeB/FeJ) strains (Harding et al., 2019). These results offer a way to reduce lung pathology without impeding host defense. Here, we extend this finding by showing that VEGFR1 blockade has similar effects in immunocompromised (RAG1KO) mice as well, measured by a reduction in the area of inflammation and without a change in bacterial burden. Following treatment with the VEGFR1 blocker SU5416, we have found an elevated ratio and an increase in the absolute number of neutrophil granulocytes in the Mtb-infected lungs in both immunosufficient and immunocompromised mice. Surprisingly however, this did not result in exacerbated pathology as the majority of the recruited neutrophils remained in the lung vasculature.
Our results indicate that further evaluation of VEGFR1 blockers as an adjunctive treatment to antitubercular drug therapy for immunocompromised populations could be worthwhile.
Supported by grants from NIH (R01 HL128778 and R01 NS123449)
Transcription factor Bhlhe40 plays a protective role during intravaginal Chlamydia muridarum infection in mice
Authors: Mercado Miguel Antonio Bernabe , Quick Charles Matthew , Li Qiang , Palmer Rachel , Kim Yejin , Huang Lu , Li Lin-Xi 
Published: August 2023

Abstract
The protein basic helix-loop-helix family member e40 (BHLHE40) is a transcription factor involved in cell cycle regulation and differentiation. It has recently emerged as a key player in immunity regulating T cell responses and cytokine production during infections.
To address the role of Bhlhe40 in Chlamydia infections, we infected WT and Bhlhe40−/− mice intravaginally with Chlamydia muridarum and monitored infection kinetics. Bhlhe40−/− mice exhibited a significant defect in their ability to clear infection compared to their WT counterparts. Single-cell RNA sequencing revealed distinct heterogeneity in the CD4+ T cell population in the female reproductive tract in WT and Bhlhe40−/− mice following C. muridarum infection. Accordingly, CD4+ T cell population in Bhlhe40−/− mice showed a marked increase in IL-10-producing T regulatory type 1 (Tr1) cells and decreased IFN-γ and GM-CSF-producing cells as assessed by flow cytometry. The overall CD4+ T cell cytokine response was diminished in the absence of Bhlhe40, as indicated by decreased levels of IFN-γ, GM-CSF and IL-17A measured by a multiplex cytokine assay. In contrast, Bhlhe40 did not appear to play an essential role in antibody responses, development of pathology, or metabolic fitness of CD4 T cells during C. muridarum infection. Lastly, IL-10 deficiency restored optimal bacterial clearance in Bhlhe40−/− mice. Altogether, our findings identified Bhlhe40 as a novel player in protective immune response against C. muridarum infection in mice.
NIH/NIAID R01 (AI139124)
NIH/NIGMS COBRE (GM103625)The American Association of Immunologists through a Careers in Immunology Fellowship
Cytokine production profiles of immune cells of stressed beta2-adrenergic receptor knockout mouse model during Chlamydia muridarum genital infection
Authors: Belay Tesfaye , Ray Alexis , Cook Kaitlyn 
Published: August 2023

Abstract
Chlamydia genital infection by Chlamydia trachomatis is the most common bacterial sexually transmitted disease worldwide. The relationships between stress and chlamydia genital infection remain unknown. Beta2-adrenergic receptor(β2-AR), the major receptor of the stress hormone norepinephrine (NE), is known to impair the function of immune cells. Stress was induced by immersing mice in cold water for five minutes daily for 21 days before infection. This study determined profiles of immune cells of stressed β2-AR KO and stressed WT C57BL/6J after 48 h of Chlamydia muridarum genital infection. Splenic T cells and differentiated bone marrow-derived macrophages and dendric cells (DCs) were purified by negative selection and stimulated by seeding T cells on anti-CD3/CD28 antibodies coated wells and by treating macrophages and DCs with LPS. After 48 h proliferation, cytokine levels in culture supernatants of the cells were determined using ELISA. Results show increased IFN-γ and IL-1β secretions but deceased IL-4 secretion by CD4+ T cells of β2-AR KO compared to WT (p&lt;0.05). The secretion of IL-13, IL-5, and IL-10 but not IL-23 in CD4 T cells of stressed β2-AR KO mice was two-fold lower than that of stressed WT. TNF-α and IL-1β secretions in macrophages and DCs or IL-12 secretion in DCs was high in stressed β2-AR KO compared to WT (p&lt;0.05). Overall, this study provides insights into the β2-AR signaling pathway’s role in suppressing the secretion of protective cytokines suggesting that inhibiting β2-AR signaling pathway may restore the function of immune cells during chlamydia genital infection. However, further study is warranted.
This work was funded by NIH grant # 1R15AI124156-01 awarded to Bluefield State University
Host and microbe adaptation underlying true fungal commensalism
Authors: Han Geongoo , Yunker Rebecca , Hasan Mohammad , Leblanc Brian , Pacia Jessica , Luong Hien , Beura Lalit , Vaishnava Shipra 
Published: August 2023

Abstract
Fungi are found ubiquitously in the mammalian gut however the role of commensal fungi in the host is poorly understood. Laboratory mice are used to model host-fungi interactions however due to ultra-clean housing they do not harbor fungi. The human commensal fungus Candida albicans is widely studied to dissect host-commensal fungi interactions however prior dysbiosis of commensal bacteria is required to colonize laboratory mice. Insights from such forced host-fungal interactions are unsuitable for extrapolating mechanisms underlying fungal commensalism and its breakdown. To discover the natural fungal commensal of mice, we used pet-store “dirty” mice. We found that pet-store mice have a high fungal burden in their feces and their gut is predominantly colonized by single species of fungus, Kazachstania pintolopesii. Furthermore, we found that K. pintolopesii isolated from pet-store mice, stably colonized laboratory mice to high levels in the presence of an intact immune system and commensal bacteria. Laboratory mice colonized with K. pintolopesii exhibited increased neutrophil frequency in blood but did not show any pathological symptoms. Surprisingly, even a systemic K. pintolopesii challenge did not show any pathology in laboratory mice indicating unique adaptations of this fungus to the murine host. Remarkably, we found that laboratory mice stably colonized with K. pintolopesii are significantly protected from systemic C. albicans challenge suggesting that commensal fungi promote systemic antifungal responses in their host. In summary, our work established a novel unmanipulated murine model of fungal commensalism and provide unique insight into cellular and molecular mechanisms of mammalian host and fungal mutualism.
This research was supported by grants from NIH (R01 DK113265), Searle Scholars program, and AAI Careers in Immunology Fellowship.
Innate lymphoid cells and interferons limit neurologic complications of Brucellosis
Authors: Moley Charles R , Chambers Catherine , Dadelahi Alexis , Ponzilacqua-Silva Bárbara , Abushahba Mostafa , Lacey Carolyn , Skyberg Jerod A 
Published: August 2023

Abstract
Brucellosis is a globally significant zoonotic disease. Human brucellosis patients develop flu-like symptoms and focal complications including arthritis and neurobrucellosis. The purpose of our study was to uncover the role of innate lymphoid cells (ILCs) in the pathogenesis of focal brucellosis. After footpad infection, we found NK cells and ILC1 cells both limit joint colonization by Brucella. Mice lacking NK cells, and in particular mice lacking all ILCs also developed marked arthritis after footpad infection. Following pulmonary infection, mice lacking adaptive immune cells and ILCs developed arthritis, neurologic complications, and meningitis. Adaptive immune cells and ILCs both limited colonization of the brain by Brucella following pulmonary infection. Transcriptional analysis of Brucella-infected brains revealed marked upregulation of genes associated with inflammation and interferon responses, as well as downregulation of genes associated with neurologic function. Type II interferon deficiency resulted in colonization of the brain by Brucella, but mice lacking both type I and type II interferon signaling more rapidly developed clinical signs of neurobrucellosis, exhibited hippocampal neuronal loss, and had higher levels of Brucella in their brains than mice lacking type II interferon signaling alone. Collectively, our findings indicate ILCs and interferons play an important role in prevention of focal complications during Brucella infection, and that mice with deficiencies in ILCs or interferons can be used to study pathogenesis of neurobrucellosis.
Supported by grants from NIH (T32 OD011126-4, R21 AI153074-02)
Neonatal helminth infection and chronic type 2 inflammation promotes immune suppression through FcγRIIb
Authors: Alexander Bridget , Miller Mindy M , Reinhardt R Lee 
Published: August 2023

Abstract
Allergic diseases are rising in industrialized countries. This contrasts with rural communities where decreased allergic incidence correlates with increased prevalence of intestinal helminth infections. While helminths and their byproducts can ameliorate allergic inflammation in adult mice with established disease, it remains unknown if early-life exposure can prevent or delay allergic disease onset. We utilized a neonatal infection model with the gastrointestinal helminth Heligmosomoides polygyrus and found that neonatal H. polygyrus colonization results in chronic infection and type 2 inflammation. This study investigates how chronic and systemic type 2 hallmarks IL-4 and IgG1 may be involved in the long-term suppressive mechanisms induced by neonatal helminth colonization. We hypothesize that IL-4-induced upregulation of the sole inhibitory Fc receptor, FcγRIIb, allows for sustained suppression of T cell mediated inflammation by increasing the activation threshold of antigen presenting cells. Increasing this threshold prevents allergen-specific T cells from becoming optimally activated and instead promotes T cell tolerance. In addition to IL-4 increasing expression of FcγRIIb on macrophages, it promotes the production of its ligand IgG1, completing the suppressive circuit. This model predicts that elimination of FcγRIIb and/or IL-4 will result in greater T cell activation and allergic inflammation. Our in vivo and in vitro data show that FcγRIIb is necessary for reducing allergic airway inflammation and T cell activation after allergen challenge. Taken together, these data support a model in which chronic helminth infection naturally mimics the suppressive effects of intravenous immunoglobulin therapy.
Supported by the National Institutes of Health NIAID training grant (Training Program in Immunology; T32-AI07405)
CD8+ lymphocytes contribute to immunologic bottlenecks in Mycobacterium tuberculosis infection
Authors: Simonson Andrew W , Chao Michael , Hopkins Forrest , Kelly Ryan , Chase Mike , Vickers Andrew , Chishti Harris , Borish Jake , Maiello Pauline , Lin Philana , Fortune Sarah , Flynn JoAnne L 
Published: August 2023

Abstract

Significance
Meta-analysis of human data suggests that M. tuberculosis (Mtb) infection confers protection against subsequent exposure. Our lab demonstrated this in a controlled experimental system using non-human primates. As the best model for natural immunity against TB, it is crucial to explore the mechanisms behind concomitant immunity. We hypothesized that CD8+ T cells would play a key role in preventing disease following secondary challenge.

Methods
Chinese cynomolgus macaques were challenged intrabronchially with a genetically barcoded library (LibP) of Mtb, allowing an adaptive response to develop. After clearing the primary infection with anti-TB drugs, CD8+ cells were depleted in half of the cohort. This was followed by a secondary Mtb challenge with a unique barcoded library (LibS). PET-CT scans enabled tracking of lesions that developed after secondary exposure. All granulomas and lymph nodes were isolated at necropsy and sequenced to determine the bacterial source (LibP vs. LibS). Spectral flow cytometry was used to analyze lymphocytes in individual tissues isolated at necropsy, examining the cytokines and other effector molecules produced by that may drive protection in the presence and absence of CD8+ cells.

Results
Our data support that CD8 depleted animals lose the ability to contain Mtb after reinfection. CD8+ cells do not appear to prevent establishment of infection independently. However, the bottleneck restricting dissemination, especially to lymph nodes, is loosened in the absence of this population. Thus, CD8+ lymphocytes are critical to immunological protection against Mtb and should be considered as a key component for vaccine and host directed therapy development.

Supported by NIH IMPAc-TB (HI-IMPACT) and T32 (5T32AI089443-13)
CD4+ T cells show a cytolytic phenotype functions in human visceral leishmaniasis
Authors: Singh Om Prakash , Chauhan Shashi Bhushan , Singh Siddharth Sankar , Engwerda Christian , Kumar Rajiv , Sundar Shyam 
Published: August 2023

Abstract
Control of Visceral leishmaniasis (VL), a parasitic disease caused by L. donovani, requires robust CD4+ T cells response to control the parasite replication by IFN-γ production and activation of macrophages. Our recent study on transcriptional signature of CD4+ T cell isolated from peripheral blood of active VL patients showed enhanced expression of genes related to cytotoxicity. In present study, we investigated expression of these cytotoxic molecules including granzyme B (GZMB), Granulysin, Perforin and NKG7 on different CD4+ T cell subsets to establish the role of GZMB in regulating CD4+ T cells functional capacity. PBMCs cells were isolated from active and post treated VL patients and endemic controls, and flow cytometry was performed. LAMP assay (CD107b expression) was performed to study the degranulation capacity of CD4+ T cells. Whole blood assay followed by ELISA was performed to measure antigen specific cytokine / GZMB production by CD4+ T cells. We found that activated and degranulating CD4+ T cells (CD38+CD107+) had higher expression of GZMB, Granulysin, perforin and NKG-7. Similarly, GZMB level in plasma and antigen stimulated whole blood culture supernatant were significantly elevated in active VL patient compared to post treatment and EC. There was no change is IFN-γ secretion when whole blood culture was stimulated with soluble leishmania antigen in presence of Con-A but a significant decline in IL-6 production was observed. In summary, VL CD4+ T cells show a cytolytic phenotype and further investigations are required to understand their differentiation and function, particularly for promoting anti-parasitic immunity for host protection and effective intervention or therapy.
Extramural Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health (TMRC grant number U19AI074321)
Metabolism and ontogeny of alveolar macrophages contribute to peripheral trained immunity and confer protection against Mycobacterium tuberculosis
Authors: Andrews James Tucker , Mercado Miguel , Huey Fischer , Pierce Katie , Ahmed-Braimah Yasir , Li Lin-Xi , Huang Lu 
Published: August 2023

Abstract
Lung alveolar macrophages (AMs) reside in the alveolar space and function as key sentinels to promote lung immune resilience. Notably, as the major cell target of early Mycobacterium tuberculosis (Mtb) infection, AMs provide a permissive cellular niche for rapid Mtb growth. However, mechanisms which regulate the permissiveness in AMs during Mtb infection remain elusive. Here, we aimed to identify intrinsic features of AMs that could be exploited to promote protective trained immunity against Mtb. Employing an intranasal β-glucan exposure model, we observed that AMs in mice treated with β-glucan acquire sustained and enhanced activation as well as metabolic reprogramming. These phenotypes are attributed to the development of monocyte-derived AMs (MoAMs) in CCR2- and innate-derived IFN-γ dependent manners. Intriguingly, MoAMs rather than pre-existing AMs exhibit canonical features of trained immunity, including a metabolic shift towards glycolysis, enhanced cytokine production and phagocytic activity. Chromatin accessibility analysis further revealed that ontogeny of AMs dictates their epigenetic landscape. Lastly, β-glucan treatment significantly reduces Mtb burden in the lung, associated with enhanced AM functions and increased productions of key proinflammatory cytokines from MoAMs. These results suggest that while tissue signals restrict the plasticity of AMs and limit their capability of being reprogrammed for vaccination and therapeutic purposes, ontogeny and metabolism are two essential intrinsic features regulating functions of AMs against Mtb infection. Furthermore, our study also highlights the importance of macrophage ontogeny as a novel determining factor of peripheral trained immunity.
Supported by grants from American Lung Association (CA-828143) and NIH (P20GM103625)
Plasmablast Ig repertoire dynamics through repeat Plasmodium falciparum challenges
Authors: Ferrer Patricia , Frank Andrew , Berry Andrea A , Lyke Kirsten E , Williamson Kim C 
Published: August 2023

Abstract
The development of natural immunity against malaria requires multiple exposures and even after protection develops against clinical disease individuals continue to be susceptible to infections. To study the dynamics of the immune response to repetitive P. falciparum (PF) infected mosquito exposures, we used controlled human malaria challenges with the same strain of PF. The homologous strain was used to eliminate differences in immune responses due to strain polymorphisms and focus on the maturation of the human immune response to repeat exposures. Consistent with the gradual immune response observed in the field, after 4 sequential exposures over the course of 2 years, symptoms decreased and the time to parasite detection on a blood smear increased significantly, but all the volunteers continued to be susceptible to infections. Anti-PF antibody levels increased over time and were able to inhibit liver cell invasion in an in vitro assay. The Ig repertoire of plasmablasts collected 7 days after peak parasitemia demonstrated large clonal expansions in one or two sequential infections that decreased after subsequent exposures. This pattern suggests a marked difference in the lineage of plasmablast and memory cells populations. Naïve B cells stimulated by PF to proliferate and differentiate into plasmablasts may fail to differentiate into memory cells that can produce both plasmablasts and memory cells following subsequent exposures. This differentiation pattern would lead to new sets of expanded clones at each PF exposure, instead of further maturation of the same antibodies generated during the first response. Such a response could enhance the diversity of the Ig pool, but would delay the generation of a strong, durable memory response
U0110852
Intestinal Epithelial Cell Intrinsic Zinc Homeostasis is Critical for Host-Microbiome Symbiosis
Authors: Yunker Rebecca , Han Geon Goo , Luong Hien , Vaishnava Shipra 
Published: August 2023

Abstract
A robust intestinal barrier is essential for maintaining host-microbiome symbiosis. Defects in the intestinal barrier are associated with a broad range of inflammatory and metabolic diseases. Pharmacological doses of Zinc (Zn) are widely used to improve intestinal barrier function; however, the precise cellular role of Zn in regulating the intestinal barrier during health and disease is not known. A better understanding of how Zn regulates the gut barrier and intestinal epithelial cells (IEC) could enable the development of targeted Zn-based therapeutic approaches. To understand the impact of Zn homeostasis we developed a mouse model with the transcription factor MTF-1 specifically deleted in IECs (MTFΔIEC). MTF-1 controls the expression of many different zinc importers and exporters. We find that MTFΔIEC mice had reduced expression of Zn homeostasis machinery, demonstrated a leaky barrier, and showed heightened neutrophil activation in the periphery. Additionally, MTFΔIEC mice had a higher bacterial load at the mucosa and were more susceptible to infection by Crohn’s disease associated adherent invasive E.coli. MTFΔIEC mice showed a striking loss of Paneth cells (PCs) from the small intestinal crypts. PCs are specialized antimicrobial-secreting cells with a unique requirement for Zn, but the exact role of Zn in PCs is not known. Based on our findings we conclude that Zn homeostasis is needed for regulating host-microbiome interaction via modulation of intestinal barrier permeability and maintenance of Paneth cells. Our work demonstrating the impact of zinc homeostasis on host-microbe interactions lays the groundwork for understanding zinc in the context of inflammatory bowel disease and dysbiosis in the mucosal microbiome.
This work was supported by the NIH [R01DK113265] to Shipra Vaishnava
Role of Bacteroides acidifaciens in gut inflammation during colitis
Authors: Staley Shanieka Caroline , Busbee Philip Brandon , Nagarkatti Mitzi , Nagarkatti Prakash S 
Published: August 2023

Abstract
Colitis is an inflammatory bowel disease characterized by chronic inflammation of the colon with significant disease-associated alterations in the gut microbiome, a term known as microbial dysbiosis. IBDs, are becoming more prevalent in industrialized areas, impacting over 1.6 million Americans. Our lab has previously shown that in mouse models of colitis, Bacteroides acidifaciens (BA) significantly increases in abundance during disease. In fact, disease severity directly correlates with the increase of abundance of this microbe. BA are obligately anaerobic, non-sporing, non-motile, gram-negative rods. This bacterium can degrade protective mucus in the colon and has properties linked to inflammation, such as enhancing immunoglobulin A (IgA) responses and producing short-chain fatty acid (SCFA) acetic acid. This study investigates the effects of the overgrowth of BA in mice with colitis as well as germ-free (GF) mice to access the ability of this microbe to induce or enhance colitis symptoms. Colitis was induced by administering the 3% dextran sulfate sodium (DSS) model. Results showed that compared to disease controls, conventional C57BL/6 mice inoculated with a high dose of BA via oral gavage had more severe colitis symptoms. These mice lost over 20% of their initial body weight, their colons were shorter, and their colons displayed ulcers, redness, and mucosal crystallization, suggesting BA significantly exacerbated the symptoms of DSS-induced colitis. Introducing BA into GF C57BL/6 mice resulted in a colitis-like phenotype with significant reduction in weight-loss and colon lengths. From this data, we deduced that BA may have the potential to induce colitis if overgrowth of this microbe reaches pathogenic levels.
Supported by NIH grant (5P20GM103641)