bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hoxa9 silencing of p16
ink4a is essential for murine lymphopoiesis
Authors: Medina Kay L , Gwin Kimberly A. 
Published: January 2023

Abstract
The homeo-domain transcription factor Hoxa9 is required for normal B and T lymphocyte development in bone marrow (BM) and thymus, respectively. Here we show that Hoxa9-deficiency is accompanied by increased expression of the cdkn2a tumor suppressor locus that encodes the cell cycle inhibitor p16Ink4a. Furthermore, we found that somatic deletion of p16Ink4a is sufficient to rescue the B and T cell progenitor deficiencies, as well as the BM lymphoid progenitor pools, in hoxa9−/− mice. In contrast, the hematopoietic stem cell (HSC) and multipotential progenitor (MPP) abnormalities characteristic of Hoxa9-deficient mice were not corrected by loss of p16Ink4a. These new data reveal that Hoxa9 repression of p16ink4a is essential for lymphoid lineage development in BM and thymus. Importantly, they highlight distinct functions for Hoxa9 in regulation of primitive hematopoietic progenitors versus those committed to the B or T cell fates.
A MYC-inducible tumor-suppressor program protects developing B cells from transformation
Authors: Tonc Elena , Chou Chun , Fujii Chika , Hsiung Sunnie , Egawa Takeshi 
Published: January 2023

Abstract
Rapid expansion of developing and activated lymphocytes is essential for establishment of a diverse antigen receptor repertoire and effective immune responses. c-MYC is a multifunctional transcription factor required for regulated proliferation of lymphocytes and their progenitors. However, c-MYC is also strongly oncogenic, both in humans and mice. Nonetheless, transformation of lymphocytes is rare, despite their extensive proliferative activity and endogenous DNA damage caused by RAG and AID activities. Thus, we hypothesized that lymphocytes are protected from transformation by unique tumor suppressor programs, potentially linked with c-MYC activity. Using the Eμ-Myc mouse model, we identified a c-MYC inducible tumor suppressive program mediated by its direct target, transcription factor AP4/Tfap4. AP4 haploinsufficiency significantly accelerated tumorigenesis of developing B cells in a cell-intrinsic manner. These tumors frequently underwent loss-of-heterozygosity of the remaining Tfap4 allele, a hallmark characteristic of other tumor suppressors. Functionally defective somatic variants of AP4 were also identified in primary human lymphomas. Mechanistically, AP4 suppressed expression of the oncogene Erg in developing B cells, which is normally suppressed in c-MYC+ pro/pre-B cells. Reducing Erg expression significantly prolonged the survival of AP4 heterozygous Eμ-Myc mice. AP4 thus protects developing B cells from transformation, at least in part, by restricting co-expression of MYC and additional oncogenes. Our findings indicate that c-MYC engages an active tumor suppressive program in B cells by inducing its direct target AP4, which is the first example of c-MYC-inducible tumor suppressors.
Modulation of RAG2 Interactions With Histone H3K4me3 Through Residue Thr490
Authors: Rodgers William A , Byrum Jennifer , Simpson Destiny , Hoolehan Walker , Rodgers Karla 
Published: January 2023

Abstract
RAG2 is essential for V(D)J recombination in developing lymphocytes, yet its localization and dynamics in cell nuclei is poorly understood. Here, we used single-cell imaging to interrogate RAG2 interactions with transcriptionally active chromatin containing H3K4me3. We measured GFP-labeled full length RAG2 (FL), the RAG2 core region alone (Core), and a T490A mutant of RAG2. Each RAG2 construct localized to nuclear regions that were adjacent to DAPI-rich heterochromatin, where the T490A RAG2 exhibited greater colocalization with H3K4me3 than either FL or Core. Furthermore, mobility measurements showed that T490A had a significantly lower rate of diffusion within the nucleus than either FL or Core proteins. Finally, mutating W453 in the T490A mutant (W453A, T490A), which blocks interactions between the RAG2 PHD region and H3K4me3, decreased the RAG2 colocalization with H3K4me3 and increased its mobility to values similar to that of FL. Altogether, these data show that Thr490 modulates RAG2 localization and dynamics in the pre-B cell nucleus, such as by affecting PHD-dependent interactions between RAG2 and H3K4me3.
NOD2 regulates distinct pathways of endogenous thymic regeneration after injury
Authors: Kinsella Sinéad , Cooper Kirsten , deRoos Paul , Iovino Lorenzo , Jain Reema , Dudakov Jarrod A 
Published: January 2023

Abstract
Although the thymus has a remarkable capacity for repair following damage, the mechanisms underlying this endogenous regeneration remain poorly understood. Our recent studies have identified two key pathways for thymic regeneration; centered on secretion of BMP4 by endothelial cells (ECs) and IL-22 from innate lymphoid cells (ILCs), which can be utilized individually as therapeutic strategies of immune regeneration. The specific regulatory mechanisms that trigger these regeneration-associated factors after damage remain unclear. Here we detail an unexpected role for the pattern recognition receptor Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) in orchestrating these distinct pathways of thymic regeneration. After acute injury, Nod2−/− mice exhibited superior overall thymic regeneration, consistent with increased levels of BMP4, IL-22, and Il-23, a key regulator of IL-22 secreted by dendritic cells (DCs). Furthermore, expression of miR29, a downstream effector of NOD2, was significantly reduced in ECs and DCs after injury, and miR29 mimics suppressed Bmp4 and Il23 expression in ECs or DCs, respectively. Consistent with a non-canonical role for NOD2 in sensing RhoGTPases, we found several RhoGTPase family members were downregulated after TBI; and modulation with small molecule inhibitors targeting Rho GTPases led to robust production of BMP4 and IL-23, with enhanced thymic regeneration after acute injury. These findings provide evidence not only of a novel master regulator of endogenous thymic regeneration, but also offer a superior therapeutic strategy for boosting thymic regeneration and T cell reconstitution after damage such as that caused by infection or cytoreductive therapy.
Early Life Adversity Programs Mast Cells Toward a Hyperactive Phenotype into Adulthood
Authors: Maradiaga Nidia C , Pohl Calvin , Mackey Emily , Moeser Adam J. 
Published: January 2023

Abstract
Early life adversity (ELA) is a risk factor in the onset and exacerbation of inflammatory disorders including allergy, asthma and chronic pain disorders such as irritable bowel syndrome (IBS). Our previous studies using murine and porcine models showed that mast cells (MCs), a key immune cell driving allergies and chronic pain disorders, display a hyperactive tissue phenotype in adult animals exposed to ELA. The mechanism by which ELA induces MC hyperactivity in adulthood remains unknown. The aim of this study was to determine if ELA programs bone marrow derived MC progenitors toward a hyperactive phenotype into adulthood by using an ELA model of neonatal maternal separation plus early weaning (NMSEW). Female pups (C57BL/6) were either raised normal handled (NH) or NMSEW. At 10 weeks, serum and mesenteric windows from jejunum were collected to evaluate histamine and tissue MC activation. Bone-marrow derived MCs (BMMCs) from mice were harvested and stimulated with IgE-DNP and IL33 to assess histamine and IL6 release, respectively. NMSEW mice exhibited increased serum histamine levels (~1.5 fold higher, P&lt;0.05), mesenteric MC numbers (~1.5 fold higher, P=0.05) and MC activation (~2 fold higher, P&lt;0.0001). BMMCs from NMSEW mice exhibited greater histamine content, IgE-mediated histamine release and IL33-stimulated IL6 release (P&lt;0.001), compared with NH BMMCs. Our data demonstrates that ELA induces lasting changes in MC progenitors programming them toward a hyperactive phenotype and increased activation in tissue. Future studies will investigate the mechanisms by which ELA drives lasting hyperactivity of MC progenitors and tissue MC hyperactivity, and its role in MC-related disorders in adulthood.
miR-155 has positive and negative roles on cytokine production in mast cells
Authors: Mohammed Zahraa abdulmohsin , Gomez Gregorio 
Published: January 2023

Abstract
Mast cells play a critical role in allergic inflammation by releasing preformed mediators such as histamine and serine neutral proteases, biosynthesizing lipid mediators like prostaglandins and leukotrienes, and synthesizing new cytokines. MicroRNA-155 (miR-155) plays a key regulatory role in the pathogenesis of allergy. The aim of this study was to investigate the biological functions of miR-155 on mast cell mediator release. MiR-155 was increased in human skin mast cells following FcɛRI crosslinking. To explore the role of miR-155 on mast cells function, we used bone marrow-derived mast cells (BMMCs) from wild type, miR-155 KO, and miR-155 Tg mice. MiR-155 had no effect on FcɛRI-induced mast cell degranulation. On the other hand, FcɛRI-induced COX-2 was significantly diminished in the absence of miR-155 suggesting that miR-155 plays a critical role in Prostaglandin D2 biosynthesis. FcɛRI-induced cytokine production was diminished in miR-155 KO BMMCs compared to WT. Interestingly, cytokine production from miR-155 KO BMMCs was increased compared to WT following LPS treatment. These findings indicate that miR-155 acts as a positive regulator in the FcɛRI pathway, and a negative regulator of the TLR4 pathway in mast cells. Current studies are aimed at determining how miR-155 functions in these pathways.
Analysis of allergen-specific T cell and IgE reactivity in milk and egg allergic children in response to progressive forms of baked milk and egg food extracts
Authors: Schulten Véronique MJ , Chen Meng , Laubach Susan , Leonard Stephanie , Peters Bjoern 
Published: January 2023

Abstract
Egg and milk allergy are among the most common food allergies in young children and are commonly outgrown. Developing tolerance is often clinically monitored by food challenge with cooked forms of egg and milk. This study characterizes IgE and T cell reactivity to four progressively cooked food extracts from egg and milk.
Egg and milk-containing food extracts were prepared from most to least cooked foods: egg muffin, meat balls frittata and raw egg; milk muffin, pizza cheese, custard and raw milk. IgE reactivity against extracts was determined by western blot and protein-specific IgE reactivity was quantified. T cell reactivity against the extracts was determined by FluoroSpot (IL-5, IFNγ and IL-10) after 24h restimulation following a two week in vitro expansion culture.
IgE reactivity varied between extracts, in a protein-specific manner. For milk, a protein band at 14 kDa corresponding in size to Bos d 4 is observed most strongly in raw milk and cheese extract, while being less reactive in custard and milk muffin. In contrast, a band at 67 kDa, corresponding to Bos d 6 in size, is most intense in milk muffin compared to raw milk, cheese and custard. For egg, trends are more consistent across the different proteins, with egg muffin showing most IgE reactivity throughout. Analysis of T cell responses showed highest IL-5 production for raw milk extract compared to custard (p=0.058), cheese (p=0.039) and muffin (p=0.097). No differences were observed for IFNγ and IL-10. For egg, no differences between extract-induced T cell reactivity was observed.
Both IgE and T cell reactivity is readily detectable against food extracts from baked forms of egg and milk. Immunological reactivity is not necessarily associated with the degree of cooking.
A proposed role for Interleukin-6 in the modulation of Th2 asthmatic responses
Authors: McLaughlin Erin M , Leon-Ruiz Beatriz 
Published: January 2023

Abstract
The incidence of allergic asthma in the United States and other industrialized countries has been increasing over the past few decades. One proposed explanation for this increase is the hygiene hypothesis, which states that a lack of early childhood exposure to high levels of environmental lipopolysaccharide (LPS) endotoxins from gram-negative bacteria increases the susceptibility to developing allergic diseases. Our lab has recently shown that LPS can indeed reduce Th2-driven, allergen-induced airway inflammation by inducing the up-regulation of the transcription factor T-bet in responding allergen-specific T cells, which we found was required to prevent the Th2 cell differentiation program. Studies have shown that like LPS, interleukin-6 (IL-6) reduces Th2 cell responses in asthma models. Due to these findings, our lab is now investigating the role of IL-6 in LPS-mediated Th2 cell suppression. In addition, some evidence suggests that IL-12 and IL-18 produced by dendritic cells are involved in the induction of T-bet by upregulating IFN-γ in T cells and other lymphoid cells. Here, we investigate the interplay of these cytokines in a house dust mite-induced asthma model in C57BL/6 (B6) mice. Through studies with IL-6 knock out and IL-6 receptor knock out B6 mice, we have shown that IL-6 modulates the expression of the IL-18 receptor on T cells, thus affecting the synergy of IL-18 and IL-12 to induce T-bet and prevent Th2 responses. We hypothesize that IL-6 affects T cell ability to respond to these cytokines by influencing the thresholds of IL-18 and IL-12 needed for T cell responses.
C-X3-C Chemokine Receptor 1 (CX3CR1) Regulates Immunopathogenesis During Fungal Asthma
Authors: Godwin Matthew S , Jones MaryJane , Yu Zhihong , Matalon Sadis , Steele Chad 
Published: January 2023

Abstract
Severe asthma with fungal sensitization (SAFS) defines a subset of severe asthmatics with allergy to multiple fungal species, including A. fumigatus. The C-X3-C chemokine receptor 1 (CX3CR1) is primarily expressed on monocytes, macrophages, and dendridic cells while expression of its ligand, CX3CL1 is increased in the presence of pro-inflammatory cytokines. Here, we show that bronchoalveolar lavage fluid (BALF) and induced sputum from human asthmatics sensitized to fungi demonstrate increased levels of CX3CL1 compared to fungal negative asthmatics, suggesting that CX3CL1 may contribute to fungal asthma severity. To this end, we examined fungal asthma severity in mice deficient in the CX3CL1 receptor (CX3CR1 -/-). The absence of CX3CR1 yielded no significant impact on type 2 biomarkers of asthma severity (e.g., levels of pro-allergic CCL17, CCL22, and IL-33) or lung eosinophil numbers. Rather, CX3CR1 deficiency was associated with heightened type 17 responses (characterized by increased production of IL-1α, IL-1β, IL-6, IL-17A, IL-22, G-CSF and CXCL2) and type 1 responses (characterized by increased IFNγ and CXCL9 production). Moreover, this inflammatory profile correlated with worse lung physiologic responses (e.g., increased dynamic and airway resistance). Taken together, these preliminary results suggest a critical role for CX3CL1 in regulating the immune response (immunopathogenesis) in fungal asthma independent of its role in cell recruitment.
Suppression of allergic airway inflammation by MCPIP1 through suppression of IL-5-producing Th2 cells
Authors: Liu Jianguo , Wang Qinghong , Ning Huan , Hou Rong 
Published: January 2023

Abstract
Allergic inflammation is mediated mainly through production of Th2 cytokines (IL-4, IL-5 and IL-13). Though we have learned much about how Th2 cells are differentiated, our understanding of the Th2 checkpoint mechanisms remains elusive. We recently found that a new RNA-binding protein, monocyte chemotactic protein induced protein-1 (MCPIP1, also named Regnase-1, encoded by Zc3h12a), suppresses Th2 differentiation and Th2 inflammation. Zc3h12a−/− mice spontaneously develop severe airway inflammation similar to asthma patients, with an increase mainly in IL-5- and IL-13-producing Th2 cells in the airway. Zc3h12a−/−CD4 T cells are mostly effector T cells and produce significant amounts of IL-5 and IL-13 but not IL-4. We further found that the differentiation of IL-5/IL-13-producing CD4 T cells is independent of IL-4 in Zc3h12a−/−naïve CD4 T cells. IL-5 expression correlates with the levels of GATA3 in Zc3h12a−/− CD4 T cells. Overexpression of MCPIP1 inhibits GATA3 and IL-5 expression through promoting GATA3 mRNA decay via RNase and CCCH domains. Furthermore, deletion of MCPIP1 in mice results in a significant increase in OVA-specific Th2 cells and severe Th2 inflammation in the airway of receipt mice after T cell transfer. Our study reveals that MCPIP1 is a potent regulator for Th2 development and function, especially the IL-5/IL-13-producing Th2 cells. MCPIP1 is a potentially new target for treatment of asthma and other Th2-mediated allergic diseases.
PAR1 signaling is involved in TCR-mediated CD8 T cell granule exocytosis
Authors: Smith Mindy Marie , Chen Hui , Hasley Rebecca B. , Karpova Tatiana , Catalfamo Marta 
Published: January 2023

Abstract
The Protease Activated Receptor (PAR1) is the receptor of thrombin, the main serine protease of the coagulation cascade. PAR1 is expressed by platelets, endothelial cells and cells of the innate immune system and mediates platelet aggregation and secretion of pro-inflammatory cytokines. PAR1 is expressed by T lymphocytes, however its role in T cell function is not well defined. We have previously shown that human CD4 and CD8 T cells express PAR1. PAR1 expression was higher in CD8 than CD4 T cells and is associated with T cell differentiation. CD8 T cell Effector Memory and Terminal Effector Memory phenotypes have higher PAR1 expression than Naïve T cells. PAR1 activation by thrombin enhanced CD8 T cell function including chemokinesis and cytokine secretion. In the present study, we address the role of PAR1 signaling in CD8 T cell mediated cytotoxicity by the granule exocytosis pathway. We found that expression of PAR1 on CD8 T cells is associated with expression of the transcription factors T-bet and Eomes and effector molecules, granzyme A, granzyme B and perforin. PAR1 activation by thrombin enhanced TcR-induced degranulation in CD8 T cells. In addition, in a redirected killing assay, we show that granule exocytosis and cytotoxicity of target cells was efficiently blocked by PAR1 antagonist (SCH79797). Confocal microscopy of the CD8 T-APC conjugates revealed that PAR1 blockade inhibit actin polymerization and decreased the docking of the Microtubule Organizing Center (MTOC) at the immunological synapse. These findings suggest that PAR1 signaling is involved in several effector functions of CD8 T cells including the cytotoxicity by the granule exocytosis pathway. These data have implications in CD8 T cell function and disease.
PD-1 regulates response to bystander activation of memory CD8 T cells
Authors: Le Catherine , Dunai Cordelia , Khuat Lam T. , Murphy William J 
Published: January 2023

Abstract
Inflammatory cytokines, released in virally infected tissues, activate bystander memory T cells, expressing CD132 and CD122, in an antigen non-specific manner through signal 3 alone to provide early anti-viral protection in an NKG2D-dependent manner. We have previously observed that IL-2 stimulation expands bystander memory CD8 T cells that are NKG2D+/Programmed cell death protein 1(PD-1)-/CD25-. However, it is unclear if the presence of PD-1 regulates the ability of memory T cells to respond to signal 3 alone. In our study, IL-2 in vitro culture for 3 days results in proliferation of memory T cells in human PBMCs and preferential expansion of memory CD8 over CD4 T cells. PD-1- CD8 T cells had greater cycling of proliferation compared to PD-1+ CD8 T cells, as observed by dilution of CPeFluor670 staining. Similarly, mouse splenocytes proliferate in response to IL-2 in vitro. Ki67+ CD8 T cells were found to be predominantly PD-1−, while ConA-stimulated Ki67+ CD8 T cells were predominantly PD-1+. Adoptively transferred memory OTI CD8 T cells but not naïve OTI CD8 T cells expanded in vivo in the liver at 3–4 days post-infection with 2×10^3 PFU murine cytomegalovirus (MCMV), and a greater percentage of PD-1− OTI CD8 T cells were Ki67 positive compared to PD-1+ OTI CD8 T cells. We conclude that the expression of PD-1 on memory CD8 T cells can regulate response to signal 3 alone. Future studies will examine the impact of PD-1 blockade on the bystander response in anti-viral protection.
Hematopoietic stem progenitor cells prevent chronic stress-induced Tregs expansion in an IL12-dependent manner
Authors: Yin Deling , Caudle Yi , Zhang Haiju 
Published: January 2023

Abstract
Physical or psychological chronic stress induces the expansion of regulatory T cells (Tregs) to contribute to immunosuppression. However, the mechanisms remain to be defined. Recent studies from us and others have shown that hematopoietic stem progenitor cells (HSPCs) significantly modulate the immune system. Since allogeneic hematopoietic stem progenitor cell transplantation contributes to chronic graft-versus-host disease (cGVHD), but attenuation of cGvHD is associated with increased frequency of Treg. We hypothesized that HSPCs prevented the over-expansion of Tregs induced by chronic restraint stress to alleviate immunosuppression. Here we demonstrate that administration of HSPCs prevent Tregs expansion and alleviate the suppressive activity of Tregs following chronic stress. Moreover, we found this protective effect is dependent on IL-12. IL-12/STAT4 signal provides a critical role against the expansion of Tregs in chronic stress. When neutralizing antibody against IL-12 or treatment with selective STAT4 inhibitor was co-administered with HSPCs in chronic stressed mice, the protective effect of HSPCs was abrogated. Additionally, HSPCs treatment promotes IL-12 production by splenocytes in chronic stressed mice. These results suggest that HSPCs can prevent chronic stress-induced Tregs expansion in an IL-12-dependent manner, which might offer a novel strategy against immunosuppression.
c-Maf-dependent Treg cell control of intestinal TH17 cells and IgA establishes host-microbiota homeostasis
Authors: Rutz Sascha , Neumann Christian , Blume Jonas , Kalies Axel , Scheffold Alexander 
Published: January 2023

Abstract
Foxp3+T regulatory (Treg) cells are crucial to maintain immune homeostasis both in lymphoid and non-lymphoid tissues. Here we demonstrate that the ability of intestinal Treg cells to constrain microbiota-dependent interleukin 17–producing T helper cell (TH17) and immunoglobulin A (IgA) responses critically required the expression of the transcription factor c-Maf. The terminal differentiation and function of several intestinal Treg cell populations, including RORgt+Tregcells and T follicular regulatory cells, was c-Maf-dependent. c-Maf controlled Treg cell-derived interleukin 10 (IL-10) production and prevented excessive phosphatidylinositol-3-OH kinase (PI(3)K)–kinase Akt–mechanistic target of rapamycin (mTORC1) signaling and inflammatory cytokine expression in intestinal Treg cells. c-Maf-deficiency in Treg cells led to a profound dysbiosis of the intestinal microbiota, which when transferred to germ-free mice, was sufficient to induce exacerbated intestinal TH17 responses, even in a c-Maf-competent environment. Thus, c-Maf acts to preserve the identity and function of intestinal Treg cells, which is essential for the establishment of host-microbial symbiosis.