bluuebunny/crossref_metadata_2025_split huggingface dataset:
Secreted IgM modulates the pool of IL-10+ B cells
Authors: McGettigan Shannon E , Diaz Lazaro Emilio Aira , Kumar Gaurav , Baumgarth Nicole , Debes Gudrun Fiona 
Published: February 2023

Abstract
IL-10+ regulatory B cells (Bregs) are increasingly recognized as critical for maintaining immune tolerance, and alterations in Breg numbers can have detrimental effects in inflammatory diseases, infection, and cancer. Bregs are found among most B cell subsets and act primarily by producing the immunosuppressive cytokine IL-10. Despite their importance, the signals that control Breg differentiation are not well defined. Here, we demonstrate that mice incapable of secreting IgM (sIgM−/−) have significantly increased IL-10+ Bregs in lymphoid organs compared to wildtype mice. These IL-10 producing Bregs are polyclonal and increased among all major B cell subsets: B-1, follicular B, marginal zone B, T2-marginal zone precursors, and transitional B cells. SIgM−/− B cells that develop in the presence of circulating IgM express IL-10 similar to that of WT B cells within the same mouse indicating that the expansions in IL-10+ B cell populations are not due to B cell-intrinsic effects based on the inability to secrete IgM. Mice that lack B cell-expressed high-affinity IgM receptor (FcμR) mirrored the IL-10 phenotype in their B-1 and MZ, but not follicular B cells, suggesting that secreted IgM can act as a negative regulator of IL-10 expression in B cell subsets via binding to surface-expressed FcμR, and potentially other IgM binding receptors. Our data indicate that IgM binding receptors control IL-10 competence in some B cell subsets thereby revealing potential novel avenues for altering Breg induction in disease settings. Funding: T32AI134646, R01AR067751, R01AI127389.
Macrophage Activation in the Lung during the Progression of Nitrogen Mustard Induced Injury is Associated with Altered miRNA Expression
Authors: Smith Ley Cody , Venosa Alessandro , Gow Andrew J , Zarbl Helmut , Laskin Jeffrey D , Laskin Debra L 
Published: February 2023

Abstract
Activated macrophages have been implicated in lung injury and fibrosis induced by the cytotoxic alkylating agent, nitrogen mustard (NM). Accumulating evidence suggests that phenotypic activation of macrophages during initiation, progression, and resolution of inflammatory responses is regulated by groups of miRNAs that act in concert to coordinate cellular activity. Herein, we determined if macrophage activation after NM injury was associated with altered miRNA expression. Male rats were exposed to NM (0.125 mg/kg, i.t.) and PCR array analysis of miRNAs involved in inflammation and fibrosis was performed in alveolar macrophages recovered from bronchoalveolar lavage. Results revealed unique and overlapping miRNA expression profiles in macrophages isolated 1, 3, 7, and 28 d post-NM. Seven miRNAs were upregulated in macrophages throughout the time-course, while three miRNAs were uniquely expressed 1 d post-NM, six at 3 d, six at 7 d, and nineteen at 28 d. Linkage with macrophage RNA-seq data showed differentially expressed miRNAs regulated mRNAs involved in STAT3, IL-6 and iNOS inflammatory signaling pathways at 1 d, and IL-4, PPAR and Sirtuin signaling at 28 d post-NM. Ingenuity Pathway Analysis predicted miR-21-5p, miR-29, miR-26a, miR-34a and let-7a as key regulators of macrophage mobilization, activation, and lipid homeostasis after NM. Collectively, these data show that NM promotes alterations in miRNA expression linked to lung macrophage responses during inflammatory injury and fibrosis. These findings provide clues on pathways regulating macrophage activation and may help identify novel therapeutic targets. This work was supported by NIH grants AR055073, ES004738, HL086621, ES005022, ES030984, and ES007148.
The impact of aging and senescence on CD4 T cell differentiation
Authors: Torrance Blake , Lorenzo Erica C , Keilich Spencer R , Al-Naggar Iman , Haynes Laura 
Published: February 2023

Abstract
With aging, the immune response and ability to return to homeostasis declines and the presence of senescent cells increases. In this study, we examined how aging and senescence impact Th subset differentiation during the response to influenza infection. In the lungs of aged mice during infection, there are significantly greater percentages of influenza-specific CD4 T cells expressing the transcription factor FoxP3, indicative of the regulatory CD4 T cell (Treg) subset, when compared to young. Higher levels of the cytokine TGFb, which can drive FoxP3 expression, were also found in the bronchoalveolar lavage (BAL) in these aged mice. Blocking TGFb with a neutralizing antibody reduced FoxP3 expression in lung CD4 T cells. Furthermore, treating aged mice with senolytic drugs prior to infection could reduce the percentage of FoxP3-expressing CD4 T cells as well as TGFb levels. Using an adoptive transfer model in which young CD4 T cells were transferred into aged hosts, we found that prior treatment of the aged hosts with senolytic drugs could reduce FoxP3 expression in the young donor cells, indicating that the senescent environment plays a role in aberrant Th subset differentiation. Finally, treatment with senolytic drugs induced differentiation of aged CD4 T cells to a healing Type 2 phenotype, which promotes a return to homeostasis, much like younger mice. These results suggest that senescent cells, via production of cytokines such as TGFb, have a significant impact on CD4 T cell differentiation, which could alter the outcome of an immune response and slow the return to homeostasis.
Subset distinct richness reduction and clonal expansion of human CD4+ and CD8+ αβ TCR repertoires with aging
Authors: achour achouak , Sun Xiaoping , Nguyen Thomas , Ko Annette , Cifello Jeffrey , Ling Chen , Sharma Jay , Hiroi Toyok , Zhang Yongqing , Chee Chia , Wood William , Wu Wells , Zukley Linda , Phue Je-Nie , Becker Kevin G. , Shen Rongfong , Ferrucci Luigi , Weng Nan-ping 
Published: February 2023

Abstract
A competent T-cell receptor (TCR) repertoire contains TCRs recognizing both novel and experienced antigens. It is widely believed that the human TCR repertoire declines with age, but its precise change in size and clonal distribution with age has not been fully determined. Here, we investigated how the size and content of TCR repertoire changes with age by analyzing the TCR repertoire of human CD4+ and CD8+ T cells and their naïve and memory subsets from 30 healthy adults aged from 25 to 85 at first visit and an average of 9-year follow-up as second visit by RNAseq. First, we calculated abTCR repertoire changes with age and found a profound reduction of the TCRa and TCRb richness in naïve CD8+ T cells and an increase of clonal expansion especially in memory CD8 T cells compared to CD4+ T cells. We also study the degree of overlap of TCRa/b repertoire between naïve and memory T cells in each subject at the same visit and found little overlap of TCRa/b unique sequences between naïve and memory CD4 T cells and ~40% of the total TCRs in CD8 T cells. Moreover, we showed elevated overlap of TCR sequences between two visits in both CD4 and CD8 T cells with memory CD8 T cells as the highest. Finally, we determined the degree of TCR clonotypes shares among different subjects via the analysis of the sharing of TCR sequences in the 30 healthy adults. As results, we observed increased sharing of identical TCR between CD4 and CD8 T cells suggesting that the public clonotypes may share with the common pathogens shared in the population, particularly in the old population. Our findings showed more profound reduction in the CD8+TCR repertoire with age compared to CD4+ TCR repertoire. All together provide evidence of ab TCR sequence-based age-associated changes of T cells and their subsets.
TCF-1 deficiency produces prion-like expansion of noncanonical regulatory T cells
Authors: Harris Rebecca , Mammadli Mahinbanu , Karimi Mobin A 
Published: February 2023

Abstract
Regulatory T cells (Tregs) are suppressive T cells which help to control and dampen immune responses. Tregs naturally suppress potentially autoreactive T cells, and are used in a variety of T cell-mediated therapies. While these cells are very useful for controlling improper or overactive immune responses in disease, they are found in low frequencies in the body, and their exact mechanisms of action are still unknown. Tregs typically express CD4, CD25, and FOXP3, with FOXP3 being considered a defining lineage transcription factor. However, in some contexts, noncanonical Tregs that are CD4+ FOXP3+ CD25− have been described, and have been shown to be suppressive in some cases. It is still unclear which transcription factors play a role in regulating these noncanonical Tregs.
We utilized a mouse strain with T-cell specific deletion of a critical transcription factor, T Cell Factor-1 (TCF-1) to determine the role of TCF-1 in controlling Tregs. We report that loss of TCF-1 specifically in T cells of mice results in cell-intrinsic expansion of CD25− Tregs. We also show that TCF-1-deficient T cells have a prion-like ability to influence Treg fate of nearby WT T cells. These CD25− Tregs are found in multiple peripheral tissues, express other functional Treg markers (CTLA-4 and IL-10), and are not the result of aberrant FOXP3 expression. Therefore, TCF-1 acts as a regulatory transcription factor for these CD25− Tregs. Modulation of TCF-1 may increase yield of noncanonical Tregs, providing benefit for T cell-mediated therapies and further study of noncanonical Tregs.
IRF4 regulates the proliferative capacity of activated B cells during B cell differentiation
Authors: Patterson Dillon , Scharer Christopher , Kania Anna , Mi Tian , Hicks Sakeenah L , Boss Jeremy M 
Published: February 2023

Abstract
Cell division is essential for B cell differentiation to a plasma cell (PC). While the cell division coupled changes in the expression of transcription factors that coordinate the PC program have been described, it is unclear how these factors coordinate the proliferative program. To address this, we used an adoptive transfer system and monitored the cell division/differentiation kinetics in response to LPS, NP-ficoll, and X31 influenza. In this system, wild-type (WT) B cells undergo at least 8 cell divisions before differentiating into PC. In contrast, Interferon Regulatory Factor 4-null (IRF4−/−) B cells began dividing normally but stalled during the proliferative response. To assess the scope of IRF4-dependent reprogramming, WT and IRF4−/− B cells in divisions 0, 1, and 3–6 were sorted for ATAC- and RNA-seq. RNA-seq data revealed hundreds of differentially expressed genes (DEG) when IRF4 was deleted that encompassed a number of gene sets critical for B cell reprogramming, including glycolysis, OXPHOS, and mTORC1 signaling. Further, MYC target genes became progressively dysregulated across divisions. Indeed, IRF4−/− cells failed to fully upregulate MYC compared to WT cells and consequently, we observed aberrant cell cycle distribution, cell growth defects, and fewer actively proliferating cells. Overexpressing MYC in IRF4−/− B cells rescued cell growth and significantly improved proliferation. ATAC-seq data also exposed hundreds of differentially accessible regions, the majority of which contained a known IRF4 binding motif and mapped to a corresponding DEG. Together, these data create a road map defining the role of IRF4 throughout differentiation, revealing a critical function in coordinating the proliferative response.
H3K27me3 demethylases restrict the magnitude of PC formation
Authors: Kania Anna , Price Madeline , Scharer Christopher , Boss Jeremy M 
Published: February 2023

Abstract
Robust differentiation of naïve B cell into antibody secreting plasma cells (PC) in response to foreign antigens is a cornerstone of the humoral immune response. PC formation is highly regulated and requires substantial epigenetic remodeling, including redistribution of histone modification H3 lysine 27 trimethylation (H3K27me3), which is associated with a repressive chromatin state and gene silencing. However, little is known about the role of the two demethylases, UTX and JMDJ3, that remove H3K27me3 in B cells. To examine whether these enzymes module PC formation, we generated mice with B cell specific deletion of UTX and JMDJ3 (dKO; Utxfl/flJmjd3fl/fl Cd19Cre/+). Stimulation of B cells with T cell independent antigens, LPS or NP-Ficoll, led to a significant increase in PC in dKO mice compared to CreCtrl mice (Cd19Cre/+). This phenotype was attributed to enhanced proliferation and differentiation of marginal zone (MZ), but not follicular B cells (FoB). dKO PC upregulated genes associated with oxidative phosphorylation metabolism and exhibited higher spare respiratory capacity. Furthermore, deletion of UTX and JMJD3 led to significant redistribution of accessible chromatin and H3K27me3. Regions with reduced chromatin accessibility in dKO PC were enriched for transcription factor motifs of known PC repressors suggesting a potential mode of regulation. Additionally, we demonstrated that UTX is the primary H3K27me3 demethylase regulating B cell differentiation and evaluated whether its demethylase activity is required to augment PC formation. Taken together, H3K27me3 demethylases are critical epigenetic regulators necessary restrain B cell differentiation.
Expression of the purinergic receptor P2RX7 marks early effector CD8+ T cells with increased potential for both long-lived circulating and resident memory cell generation
Authors: Silva Henrique Borges da , Vardam-Kaur Trupti , Carvalho Igor Santiago , Peng Changwei , Wanhainen Kelsey M , Jameson Stephen C. 
Published: February 2023

Abstract
Memory CD8+ T cells protect against secondary viral infections. They develop and maintain exclusively in circulation (e.g. central memory - Tcm) or are excluded from re-circulation (resident memory - Trm). Circulating memory CD8+ T cells arises from memory precursors (MPs) which express memory, pro-survival, and pluripotency molecules. Trm generation, in contrast, is still not fully understood. Previous reports suggest that Trm and Tcm have a common precursor present at the early effector phase; yet, the nature of this precursor is elusive. We have found that the extracellular ATP receptor P2RX7 promotes both Tcm and Trm generation. Moreover, P2RX7 is quickly upregulated in some (but not all) early effectors and early P2RX7 ablation hinders both Tcm and Trm generation. Thus, we postulated that P2RX7 in early effectors may mark a Tcm/Trm common precursor. Comparison between high (P2RX7hi) and low (P2RX7lo) P2RX7-expressing CD8+ T cells shows a correlation between memory markers and P2RX7, with CD62L+ Tcm precursors exclusively found in P2RX7hi cells. RNA-seq of P2RX7hi and P2RX7lo early effectors show survival, memory and pluripotency genes and pathways are upregulated in P2RX7hi cells. Conversely, many terminal effector and apoptosis genes are upregulated in P2RX7lo cells. P2RX7lo early effectors and MPs have increased apoptosis. Upon transfer into infection-matched mice, P2RX7hi MPs preferentially survive and form Tcm compared to P2RX7lo MPs. This is even more apparent when P2RX7hi and P2RX7lo early effectors are compared: approximately 100x more P2RX7hi cells form memory when compared to P2RX7lo cells, both Tcm and Trm. Our data suggest that P2RX7 in early effector CD8+ T cells promotes the generation of a common Tcm/Trm precursor.
The lymphoid microenvironment controls duration of T cell - DC interactions to promote accelerated effector cell generation
Authors: Altenburger Lukas Matthaeus , Harada Yosuke , Dehio Philippe , Ruef Nora , Mehling Matthias , Stein Jens Volker 
Published: February 2023

Abstract
Naïve T cells and dendritic cells (DCs) are drawn to lymphoid tissue by the chemokine receptor CCR7, where its ligands CCL19 and CCL21 are secreted by lymphoid stroma. There, CCR7 fuels the fast migration of naïve T cells to expedite encounters with DCs presenting cognate pMHC, leading to the formation of long-lasting contacts. Direct in situ observations in mouse models have shown that after approximately 12–24 h, activated T cells detach from DCs before undergoing cell division and effector T cell differentiation. Yet, the mechanisms underlying T cell release from DCs, and hence termination of TCR signal integration, are not well understood. Using a reporter system for TCR signaling, we show here that CD8+T cell detachment from DCs does not occur efficiently in the absence of CCR7 ligands, suggesting that T cells do not intrinsically cease TCR signal integration. In contrast, after a short period of unresponsiveness, ex vivo stimulated T cells increasingly separate from DCs in response to CCR7 ligands in line with in vivo kinetics of detachment. Using ex vivo and in vivo imaging, we identify a critical role for phosphoinositide-3-kinase and the Rac activator DOCK2 in calibrating CCR7-dependent duration of T cell-DC interactions. To assess the impact of enforced T cell-DC separation, we examined effector differentiation kinetics as a function of interaction duration with DCs. Environmentally triggered CD8+T cell detachment from DCs positively correlated with their entry into proliferation and granzyme B production while limiting PD-1 expression. In sum, our data assign a novel function to CCR7 ligands secreted by lymphoid stroma to limit the duration of CD8+T cell - DC interactions for accelerated effector T cell generation.
Understanding the role of hnRNPA1 on T cell differentiation
Authors: White Theresa L , Gable Matthew , Jin Ye , Morel Penelope 
Published: February 2023

Abstract
Regulatory T cells (Treg) play a critical role in preventing autoimmunity diseases and maintaining tolerance in various tissues, particularly the gut. Peripheral derived Tregs (pTregs) are especially crucial in gut homeostasis and tolerance to commensal and food antigens. We have previously shown that knockdown of the RNA-binding protein, heterogeneous nuclear ribonucleoprotein (hnRNP) A1, reduces in vitro pTreg induction upon low TCR stimulation. In addition, we have shown that, under conditions of low TCR stimulation, in which pTregs are induced, hnRNP A1 is phosphorylated by Akt. In order to explore the impact of hnRNP A1 phosphorylation by Akt on pTregs induction we have generated a mutant mouse model, hnRNPA1-S199 in which the known Akt phosphorylation site on hnRNP A1 is mutated to Alanine. We have examined the induction of pTregs in vivo using an adoptive transfer model of OT-II TCR transgenic mutant (hnRNPA1-S199A) and wild-type naïve CD4 T cells followed by oral OVA administration. In addition, we are examining the induction of pTregs in vitro using OVA peptide presented by wild-type and mutant (antigen presenting cells) APC from the spleen. Preliminary data showed a decrease in pTreg induction and proliferation when naïve mutant T cells are stimulated either in vitro or in vivo with OVA. Furthermore, we observe that mutant APC have a reduced ability to induce proliferation and pTreg induction in both mutant and WT T cells. These data suggest that hnRNP A1 has important functions in both T cells induction and antigen presentation.
Senescence-associated β-galactosidase activity and other markers of senescence are present in human peripheral blood CD8+ cells during healthy aging
Authors: Dewald Hannah K , Martínez-Zamudio Ricardo Iván , Vasilopoulos Themistoklis , Radeny Joycelyn , Herbig Utz , Fitzgerald-Bocarsly Patricia 
Published: February 2023

Abstract
Aging is associated with a decline in the immune system, termed “immunosenescence”. Cellular senescence is defined by persistent cellular growth arrest and overall loss of function. If immune cells undergo cellular senescence in vivo, and if it has a role in immunosenesence, remains controversial due to the lack of specific markers to identify these cells. Human CD8+ T cells from younger and older donors were isolated from blood and labeled with a fluorescent substrate for senescence-associated b-galactosidase (SA-βGal). CD8+ T cells were sorted based on SA-βGal and analyzed by qRT-PCR, RNA sequencing, and microscopy. We found a higher percentage of CD8+ T cells with high SA-βGal activity in the older cohort. SA-βGal high CD8+ T cells displayed increased p21, p16INK4a, and inflammatory cytokine transcripts. They also had greater DNA damage response foci and p16INK4a protein and had deficient proliferation. SA-βGal increased as T cells matured, which was consistent regardless of age. Intriguingly, a portion of effector cells did not exhibit a senescent phenotype and maintained low SA-βGal. RNA sequencing of CD8+ T cells revealed cells with low, medium, and high SA-βGal had distinct profiles. In addition, SA-βGal high CD8+ T cells had larger mitochondrial mass than cells with low SA-βGal as measured by MitoID staining. This may indicate differences in metabolism, which may contribute to senescence. The presence of p16INK4a, DNA damage, and inflammatory cytokines and deficient proliferation demonstrate that SA-βGal is a strong indicator of cellular senescence in CD8+. T cells. SA-βGal can be leveraged to further identify senescent immune cells and elucidate cellular senescence’s role in immunosenesence.
Anergy-derived Treg cell differentiation in the neonatal mouse hepatic microenvironment
Authors: Morales Milagros Silva , Mueller Daniel L 
Published: February 2023

Abstract
The neonatal environment is a natural scenario to study the effects of peripheral self-antigen recognition and induction of immune tolerance within the CD4 T lymphocyte repertoire. Interestingly, we have found that polyclonal Nrp1+ CD73+ anergic conventional CD4 T cells and Foxp3+ regulatory T cells (Tregs) accumulate in the neonatal liver. These observations make the neonatal liver an interesting place to study anergy-derived Foxp3+ Treg cell differentiation. We hypothesize that self-reactive CD4 T cells become anergic in neonates and generate Treg cell progenitors. Furthermore, we predict that unlike secondary lymphoid organs, the neonatal liver microenvironment fails to support anergy maintenance and, therefore, allows anergy-derived Treg cell progenitors to differentiate into Foxp3+Tregs. Accordingly, the objective of this study was to specifically analyze the induction of CD4 T cell anergy and the trans-differentiation of anergic conventional T cells into the Foxp3+ Treg cell lineage within the neonatal liver. We now report that anergic OT-II CD4 T cells partially reverse their anergic phenotype and give rise to Foxp3+Tregs cells within the hepatic environment when transferred into neonatal mice that ubiquitously express an OVA transgene. These findings support the model that a change in the metabolism of anergic CD4 T cells within the neonatal liver leads to cell-cycle progression and chromosomal replication, which then allows for the complete de-methylation of the Foxp3CNS2 locus and differentiation into the Foxp3+ Treg lineage. Future experiments will analyze the importance of enzymes such as DNMT and TET proteins that regulate the epigenetic state of Treg cell progenitors within the anergic cell compartment.