bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microbiota-derived lactate control hematopoiesis and erythropoiesis through regulating stem cell factor from leptin receptor+ niche cells in the bone marrow
Authors: Kim Tae-Young , Lee Yong-Soo , Kim Yeji , KIM SEUNGIL , Lee Su-Hyun , Kweon Mi-Na 
Published: January 2023

Abstract
Although the functional interplay between the intestinal microbiota and the distant sites beyond the gut have been identified, it is still unveiled how microbiota-derived metabolites are involved in determining the fate of hematopoietic stem cells (HSC). In this study, we are aiming to investigate a role of microbiota-derived lactate in hematopoiesis using G-protein-coupled receptor (Gpr) 81, a known lactate receptor, deficient (Gpr81−/−) mice. We found that total numbers of hematopoietic cells and numbers of Lin−c-Kit+Sca-1+ HSC were significantly reduced in the bone marrow (BM) from Gpr81−/−mice when compared to heterogenic (Gpr81+/−) mice in steady-state condition. Of note, expression levels of stem cell factor (SCF), which is required for maintenance of HSC and erythropoiesis, were significantly decreased in Leptin-receptor expressing (LepR+) stromal cells around sinusoidal vascular of BM tissue obtained from Gpr81−/−mice when compared to those from Gpr81+/− mice. In addition, Gpr81deletion considerably reduced hematopoietic recovery and SCF expression in the BM damaged by irradiation. Oral administration with probiotics or lactate stimulated SCF secretion from LepR+ BM stromal cells and increased hematopoiesis and erythropoiesis. Furthermore, colonization of lactate-producing bacteria in GF mice also accelerated HSC number and SCF expression. Taken together, these results demonstrate that microbiota-derived lactate stimulates SCF secretion by LepR+ BM stromal cells and subsequently activate hematopoiesis and erythropoiesis in a Gpr81-dependent manner.
Short chain fatty acids regulate T cell metabolism to promote IL-22 production and gut immunity
Authors: Yang Wenjing , Yu Tianming , Huang Xiangsheng , Bilotta Anthony J , Yao Suxia , Cong Yingzi 
Published: January 2023

Abstract
Interleukin-22 (IL-22) is critical in gut immunity. Both innate lymphocyte cells (ILCs) and CD4+ T cells produce IL-22. ILCs provide a rapid source of IL-22 that is essential for early protection of epithelial barrier function upon enteric infection and inflammatory insult, while T cells become the dominant source of IL-22 in the intestinal lamina propria during chronic intestinal inflammation. Microbiota is central in IL-22 production in the intestines, however, the factors that regulate IL-22 production in T cells and ILCs in the intestines, and the mechanisms involved remain unclear. We found that microbiota-derived short-chain fatty acids (SCFAs) promoted IL-22 production in T cells and ILCs through their inhibition of HDAC activity but not GPR43. Additionally, SCFAs upregulated IL-22 production by promoting aryl hydrocarbon receptor (AhR) and hypoxia-inducible factor (HIF)1α expression, which were differentially regulated by mTOR and Stat3 pathways. Furthermore, HIF1α directly bind to the il22 promoter, and SCFAs increased HIF1α binding to the il22 promoter through histone modification. SCFAs enhanced oxygen consumption and glycolysis, which mediated SCFA-induced IL-22 production. Hypixic condition enhanced the SCFAs induction of IL-22, and glucose facilitated SCFAs induction of IL-22 production in a dose-dependent manner. SCFA supplementation protected intestines from Citrobacter Rodentium infection and dextran sodium sulfate (DSS) insult, which was mediated by enhanced IL-22. SCFAs promoted T cell IL-22 production from patients with Crohn’s disease through inducing AHR and HIF1α. These findings establish the roles of SCFAs in inducing IL-22 production in T cells and ILCs to maintain the intestinal homeostasis.
Complement C3aR loss drives colorectal cancer by modulating gut microbiota
Authors: Guglietta Silvia , Carloni Sara , Darwich Abbass , Fosso Bruno , Weber Lukas M , Robinson Mark D , Pesole Graziano , Rescigno Maria , Krieg Carsten 
Published: January 2023

Abstract
Several lines of evidence suggest that inflammation plays a pivotal role in the development and progression of colorectal cancer (CRC) and can be unleashed by the loss of innate immunosurveillance. The complement system is a central component of immunity and is essential for intestinal homeostasis. Emerging evidence suggests that complement dysregulation is involved in the development and progression of CRC. Here we show for the first time that methylation of the complement anaphylatoxin C3a receptor (c3aR1) in CRC patients results in decreased overall survival and events-free survival. Based on our clinical findings, we ablated c3ar1 in the spontaneous APCMin mouse model of intestinal tumorigenesis. Loss of C3aR in this model resulted in a shift of tumorigenesis from the small intestine to the colon, therefore more closely mirroring human CRC. By performing microbiota sequencing and fecal microbiota transplantation (FMT) experiments, we found that loss of C3aR resulted in the establishment of a pro-inflammatory microbial flora, which fostered strong Th1/Th17 cell inflammation. Our findings highlight a previously unrecognized oncosuppressive role for C3aR in CRC that could be exploited as a biomarker or for therapeutic intervention.
Steady-state interferon-stimulated gene expression in the intestinal epithelium depends on interferon lambda and the bacterial microbiome
Authors: Van Winkle Jacob , Peterson Stefan , Wheadon Michael , Lee Sanghyun , Baldridge Megan , Nice Timothy 
Published: January 2023

Abstract
Distinct cellular responses have evolved that are specialized for eliminating pathogens in mucosal surfaces, such as the gastrointestinal tract. In particular, intestinal epithelial cells (IECs) are uniquely responsive to interferon lambda (IFN-λ) and depend on this cytokine for antiviral defense to a greater extent than other types of interferon. IFN-λ signaling protects IECs by inducing expression of antiviral IFN-stimulated genes (ISGs), but it is unclear how this signaling pathway interacts with the intestinal microbiome. We find that depletion of the intestinal microbiome with broad spectrum antibiotics significantly reduces steady-state ISGs in the gastrointestinal tract when assessed by whole-tissue RNA sequencing. Steady-state ISG expression is also significantly reduced in mice with conditional knockout of IFN-λ receptor (IFNLR) in IECs. These data suggest that enteric bacteria stimulate expression of IFN-λ and, subsequently, epithelial ISGs at homeostasis. Strikingly, imaging data reveals distinct pockets of IFNLR-dependent ISGs throughout the small intestinal epithelium. These highly localized ISGs are also dependent on the presence of bacteria and IFNLR expression by IECs. Notably, in addition to localized ISG expression along the length of the gastrointestinal tract, ISG expression is concentrated in the most mature IECs at the tips of individual villi. These novel observations indicate that ISGs are robustly expressed in localized regions of the intestinal epithelium at homeostasis. This robust ISG expression depends on the bacterial microbiome and may preemptively activate antiviral defenses in vulnerable IECs to improve host fitness against enteric viruses.
Early life selection of gut microbiota specific T cells
Authors: Ruiz Daniel Fernando Zegarra , Kim Dasom , Norwood Kendra , Majumdar Shubhabrata , Wu Wan-Jung , Kim Myunghoo , Bettini Matthew , Diehl Gretchen 
Published: January 2023

Abstract
AIRE-dependent expression of tissue-specific antigens by medullary thymic epithelial cells allows for the selection of non-autoreactive T cells, supporting self-tolerance. Although gut microbiota is known to educate the immune system, balancing effector and regulatory T cells responses, it remains unknown how bacteria-specific T cells are selected. Here we studied how thymic T cell development is altered after colonization with model intestinal microbes. Colonization of mice at weaning induced thymic expansion of bacteria-specific naive T cells. Remarkably, bacterial DNA was found in the thymus of colonized mice and 16s rDNA sequencing identified bacterial DNA from a broad range of intestinal microbes in the thymus of steady-state mice. We identified enrichment of CX3CR1+ dendritic cells (CX3+ DCs) after microbial colonization and depleting these cells or inhibiting their antigen-presentation suppressed induction of bacteria-specific T cells. Further, depletion of the gut microbiota with antibiotics reduced positive selection, bacterial 16s, and CX3+ DCs in the thymus. In older mice, we did not observe microbial DNA in the thymus, altered CX3+ DCs, or expansion of microbiota specific T cells, indicating a developmental window where intestinal microbes can regulate thymic output. Using models of microbiota-specific T cell immunity or pathogen infection, we demonstrate thymic microbiota-specific T cells can differentiate into intestinal effector T cells, offering protection or mediating pathology. Together, our data suggests trafficking of bacteria to the thymus by intestinal DCs drives T cell selection of microbiota-specific T cells to shape peripheral immunity against pathogens and the microbiota itself.
The Role of Innate Lymphoid Cells in Immune Regulation and Fetal Protection During Allogeneic Pregnancies
Authors: Chung Douglas , Wong Emily , Han SeongJun , Elford Alisha , Garcia-Batres Carlos , Ohashi Pamela S 
Published: January 2023

Abstract
Maternal immune tolerance against paternal alloreactive antigens expressed by the fetus is essential in the development of successful pregnancies. Disturbances of immunoregulatory mechanisms by genetic modifications or viral infections results in aberrant placental development, intrauterine growth restriction (IUGR), and fetal loss. Mechanisms of immune regulation during pregnancy has not been fully elucidated. Our lab and others were the first to uncover a novel subset of regulatory innate lymphoid cells (ILCregs) that suppressed immune responses in chronic viral infections, organ transplant rejection, and cancer. In this study, we identified a subset of decidual NK1.1+ ILC1s in healthy murine pregnancies that expressed surface markers and intracellular cytokines reminiscent of an ILCreg phenotype. Interestingly, these characteristics were more abundant early in gestation compared to mid-late gestation. Furthermore, depletion of NK1.1+ ILC1s using neutralizing antibodies induced fetal destruction in allogeneic (C57BL/6J female X BALB/c male), but not in syngeneic pregnancies (C57BL/6J female X C57BL/6J male). This highlights the importance of allogenicity in fetal destruction in the absence of NK1.1+ ILC1s. Decidual ILC1s have been shown to promote trophoblast invasion, placental angiogenesis, and in utero fetal growth during pregnancy. However, we are one of the first groups to thoroughly investigate potential immunosuppressive role of decidual ILC1s to prevent immune-mediated fetal destruction. Further elucidation of immune tolerance mechanisms during pregnancy may uncover novel therapeutic targets for pregnancy-related complications such as preeclampsia and spontaneous miscarriages.
Role of the microbiota in the development of intraepithelial CD4+CD8aa+ T cells
Authors: Barragan Luisa Cervantes , Royer Charlotte 
Published: January 2023

Abstract
The small intestine contains CD4+CD8aa+ double-positive intraepithelial T lymphocytes (DP IELs) which originate from intestinal CD4+ T cells through downregulation of the transcription factor ThpoK and have regulatory functions. We have previously found that development of DP IEL depend on the presence of Lactobacillus reuteri. This species induced DP IELs in germ-free mice and conventionally-raised mice lacking these cells. L. reuteri did not shape DP-IEL-TCR repertoire, but generated indol derivatives of tryptophan that activated the aryl-hydrocarbon receptor in CD4+ T cells. Monocolonization of germ-free mice with L. reuteri resulted in the induction of DP IEL, however reconstitution with a complex microbiota + L. reuteri induce a much larger DP IEL population suggesting that additional bacterial species are required for optimal DP IEL development. In this study we have aimed at elucidating additional bacterial species from the intestinal microbiota that contribute to the development of DP IEL.
Targeting MAIT cells by vaccination with S. enterica serotype Typhimurium to prevent lung infections
Authors: Paynich Mallory L , Hartmann Nadine , Riffelmacher Thomas , Kronenberg Mitchell 
Published: January 2023

Abstract
Nearly all currently licensed vaccines elicit antibody responses to induce long-lasting immunity. For intracellular pathogens, to some extent out of reach for antibodies, protective vaccination will require not just antibody production, but also T cell-mediated responses. Mucosal Associated Invariant T (MAIT) cells recognize microbial vitamin B metabolites presented by the MHC-I-like molecule, MR1, via a semi-invariant TCR. These innate-like T cells are present at low levels in mice in mucosal tissues, especially the lung, as well as other sites such as blood, liver and spleen. Previous studies have demonstrated that Salmonella enterica serotype Typhimurium potently expands long-lived MAIT cells to nearly 40% of lung αβ T cells. Using this model, we determined that expansion of MAIT cells requires infection with intracellular bacteria, as an invasion mutant of S. enterica does not induce MAIT cell expansion. Following treatment with an attenuated strain of S. enterica, MAIT cells expand into short-term effector memory (CD127−KLRG1+) and memory precursor (CD127+KLRG1−) populations that differ in cytokine, transcription factor, and metabolic profiles. Following adoptive transfer, CD127+ MAIT cells, but not KLRG1+ cells, protect mice from infection with a different bacterium, Streptococcus pneumoniae, a leading cause of pneumonia and other diseases. Further, vaccination with S. enterica limits S. pneumoniae-induced mortality in mice. These studies demonstrate that some intracellular bacteria induce distinct, long-lived MAIT cell populations, and that these cells are a promising target for vaccines against lung pathogens.
Aiolos and T-bet cooperate to repress the ILC3 transcriptional program in human innate lymphocytes
Authors: da Silva Cristiane Sécca , Cella Marina , Gamini Ramya , Collins Patrick , Zhao Shanrong , Peng Vincent , Robinette Michelle , Schettini Jorge , Zaitsev Konstantin , Gordon Willian , Bando Jennifer K. , Yomogida Kentaro , Cortez Victor , Fronick Catrina , Fulton Robert , Lih Ling Lin , Gilfillan Susan , Flavell Richard A , Shan Liang , Artyomov Maxim N. , Bowman Michael , Oltz Eugene M , Jelinsky Scott , Colonna Marco 
Published: January 2023

Abstract
Innate lymphoid cells (ILCs) are tissue-resident lymphocytes devoid of antigen-specific receptors that provide an immediate source of cytokines in early immune responses and are enriched in mucosal tissues. Human ILC3s that produce the cytokine interleukin-22 and express the transcription factor RORγt have been shown to be able to convert into ILC1-like cells that produce mainly IFN-γ and express T-bet, in vitro. Whether this conversion also occurs in vivo remains unclear. In the present study we found that ILC3s and ILC1s in human tonsils represented the ends of a spectrum that included additional discrete subsets with intermediate transcriptional signatures. This finding strongly suggests that the ILC3 to ILC1-like conversion also occurs in vivo in humans. Gene expression analysis showed that the transcription factors Aiolos and T-bet were induced in the subsets closer to the canonical ILC1 subset. Chromatin studies indicated that Aiolos and T-bet cooperate to repress regulatory elements active in ILC3s. Ectopic expression of Aiolos and T-bet in the ILC3-like cell line MNK-3 repressed the production of IL-22 and induced IFN-γ. We conclude that Aiolos and T-bet cooperate to repress the ILC3 transcriptional program therefore contributing to the ILC3 to ILC1-like conversion.
TREM2/β-catenin attenuates macrophage pyroptosis to promote bacterial eradication of pyogenic bacteria
Authors: Wei Liwen , Wang Yi , Liang Siping , Wu Yongjian , Ming Siqi , Wu Minhao 
Published: January 2023

Abstract
Triggering receptors expressed on myeloid cells 2 (TREM2) inhibits inflammatory responses, but promotes macrophage-mediated bacterial clearance both in vivo and in vitro. However, the underlying mechanism remains unclear. Our study demonstrated that deficiency of TREM2 significantly enhanced four common pyogenic bacteria-induced macrophage pyroptosis, including Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pneumoniae and Escherichia coli. Blockage of pyroptosis by knocking out Caspase-1 or knocking down gasdermin D (GSDMD) enhanced macrophage-mediated pyogenic bacteria clearance. And treatment with Caspase-1 inhibitor relieved TREM2 deficiency-mediated suppression of pyogenic bacteria clearance. In addition, TREM2 enhanced β-catenin stability via promoting its phosphorylation at S675. Moreover, silencing of β-catenin enhanced pyroptosis and impaired Pseudomonas aeruginosa clearance, while overexpression of β-catenin inhibited pyroptosis and restored bacterial elimination in TREM2-silenced macrophages. Notably, in vitro studies suggested that TREM2/β-catenin suppressed NLRP3 and NLRC4 inflammasome activation at priming and/or assembly stage. Collectively, our study provides a novel mechanism of TREM2-mediated anti-pyogenic bacterial immunity and explores the relationship between pyroptosis and bacterial eradication.
Phenotypic and functional characterization of lung resident lymphocytes of BCG vaccinated mice
Authors: McAllister Madeline K , Tripathi Deepak , Radhakrishnan Rajesh Kumar , Thandi Ramya Sivangala , Paidipally Padmaja , Vankayalapati Ramakrishna 
Published: January 2023

Abstract
Mycobacterium tuberculosis (Mtb) remains to be a leading cause of morbidity and mortality, causing an estimated 1.3 million deaths annually. It is known that intranasal Mycobacterium bovis Bacille Calmette-Guérin (BCG) vaccination in mice has proven to provide superior protection against pulmonary TB, as compared to parenterally administered BCG. In the current study, we determined the phenotype and function of lung-resident lymphocytes in intranasally BCG vaccinated mice. C57BL/6 mice were vaccinated intranasally with live-attenuated BCG and lung lymphocytes were isolated and stained for immunophenotyping via flow cytometry at 24, 48, and 72 hours post-vaccination. At 48 hours post-vaccination, we have observed an expansion of CD69+, CD103+, and CD69+CD103+ lymphocytes within the lung of vaccinated mice. Studies are underway to determine the phenotype and function of lung-resident lymphocyte subsets and their expansion capacity at three months after BCG vaccination and Mtb infection.
Androgen receptor activity underlies sex differences in lung-resident ILC2 functional responses during influenza virus infection
Authors: Kovats Susan , Turner Sean , Karlik Anna , Miller Reegan , Ainsua-Enrich Erola , Kadel Sapana 
Published: January 2023

Abstract
Lung-resident group 2 innate lymphoid cells (ILC2s) produce type 2 cytokines and facilitate tissue repair in response to alarmins such as IL-33 released during respiratory virus infection, but they also may be functionally suppressed by type 1 cytokines. Lung ILC2s express notably high levels of intracellular androgen receptor (AR) compared to ILC1s, T and B cells. To test the hypothesis that females and males show differential ILC2 responses in influenza virus (IAV) infection, we analyzed the numbers and functional responses of lung ILCs in IAV infected mice. On days 3–10 post-infection, lungs of female mice contained greater numbers of ILC2s and ILC1s compared to males. However, the female ILC2s were preferentially suppressed at the peak of infection, with a dampened type 2 program manifest as attenuated proliferation, decreased IL-5 and amphiregulin production, reduced expression of GATA-3 and IL-33R and increased surface IFNGR. IFNG levels in the lung were comparable between sexes at day 7 post-infection, suggesting intrinsic differences in ILC2 responses to interferons. Indeed, naïve female ILC2s showed higher expression of IFNGR and higher phospho-STAT1 levels following stimulation by IFNG. ILC2s in naive male mice with lymphocyte-restricted AR deficiency displayed levels of IFNGR comparable to female mice, suggesting AR activity underlies sex differences in intrinsic IFNGR expression. Early life orchiectomy revealed that endogenous androgens decreased ILC2 numbers but protected males from suppression of ILC2s in IAV infection. Taken together, our data show that AR activity preserves canonical ILC2 function in males during IAV infection and may help to explain the documented human gender differences in immunity to IAV.
Lung resident memory B cells are a common and functionally significant component of lung adaptive immunity
Authors: Barker Kimberly A , Shenoy Anukul T , Stauffer-Smith Nicole , Arafa Emad Isam , de Ana Carolina Lyon , Barron Alex , Aihara Fumiaki , Martin Ian , Zhong Xuemei , Kepler Thomas B , Browning Jeffrey L , Jones Matthew , Quinton Lee , Mizgerd Joseph P. 
Published: January 2023

Abstract
Resident memory B cells (BRM) in influenza-recovered mouse lungs were recently described, but whether other types of infections elicit these cells is unknown. The relevance of BRM in human lungs and to lung immune defenses also remains unexplored. Using flow cytometry and immunofluorescence, we found that respiratory pneumococcal exposures in mice elicited lung BRM without concurrent tertiary lymphoid structure formation. Additionally, flow cytometry analysis of normal human lung tissue showed that human lungs are enriched compared to human blood for B cells bearing a resident memory phenotype. These findings indicate that lung BRM are a common feature of antigen-experienced lungs. Multiple mouse models were used to address the contributions of B cell immunity to anti-pneumococcal lung defenses. Mice exposed to a low virulence pneumococcal strain 4 weeks previously were well-protected from a serotype-mismatched pneumococcal challenge. When previously exposed mice were depleted of circulating B cells (but not lung B cells) with anti-CD20 treatment before the challenge infection, there was no effect on the acquired lung immunity. However, a genetically engineered mouse strain allowed effective depletion of lung B cells bearing PD-L2 (a mouse memory B cell marker) from previously exposed mice, and doing so before the virulent pneumococcal challenge resulted in substantial defects in bacterial clearance compared to mice with lung B cells intact. These results provide the first direct evidence of a role for lung BRM in anti-bacterial lung immunity. Notably, this defense was pneumococcal serotype-independent, distinguishing it from the serotype-specific immunity elicited by current pneumococcal vaccines.