bluuebunny/crossref_metadata_2025_split huggingface dataset:
AhR ligands differentially affect thymus and peripheral lymphoid organs by targeting T cells and their functions leading to pro- or anti-inflammatory responses
Authors: Singh Narendra Prasad , Miranda Kathryn , Jackson Dominique , Sumpter Steilan , Singh Udai P , Nagarkatti Mitzi , Nagarkatti Prakash 
Published: January 2023

Abstract
TCDD, FICZ, and Resveratrol (RES) are potent ligands of aryl hydrocarbon receptor (AhR). TCDD is well known to cause thymic atrophy but the effects of FICZ and RES have not been studied to date. In the current study, we investigated the effect of AhR ligands in vivo. We chose these AhR ligands for their different origin-TCDD, an environmental contaminant, FICZ, endogenously generated, and RES, found in plant products. To this end, C57BL/6 mice were treated with vehicle (corn oil) or TCDD (10 μg/kg bw) or FICZ (10 μg/kg bw) or RES (100 mg/kg bw) by oral gavage. Three days post treatment, thymi and spleens were harvested and stained with fluorochrome-labelled Abs against various T cell surface markers and analyzed by flow cytometry. We observed significant effect of TCDD on decreasing thymic weight and thymic cellularity, when compared to vehicle. FICZ, on the other hand, had no significant effect on thymus. RES, however, significantly caused increase in thymic weight as well as thymic cellularity. Upon analysis of various T cell populations in the thymus, TCDD caused significant downregulation of almost all the markers (CD3, CD4, CD8, CD25, CD44, and αβTCR) whereas, FICZ and RES had moderate effects on thymic T cell subpopulations. Upon analysis of spleen, all the three AhR ligands had mixed effects. We observed significant effect of TCDD and RES in generation of Tregs, when compared to vehicle. FICZ, on the other hand, suppressed Tregs but significantly increased Th17 cells. Together, our studies suggest that although TCDD, FICZ, and RES are AhR ligands, they had different effects on both thymus and spleen. TCDD and RES had role in inducing immune suppression by generating more Tregs, whereas, FICZ had a role in inflammation by generating more Th17 cells.
Roles of Toll-like Receptors in Regulating Fibroblastic Reticular Cells Pathobiology during Sepsis
Authors: Deng Meihong , Li Yiming , Chen Tianmeng , Chen Kong , Billiar Timothy R 
Published: January 2023

Abstract
Fibroblastic reticular cells (FRCs), a subpopulation of stromal cells in lymphoid organs and fat-associated lymphoid clusters (FALCs) in peritoneal fat, play immune-regulatory roles in the host defense. However, the mechanisms underlying the regulation of FRC pathobiology, especially in response to Toll-like receptor (TLR) signaling is unclear. Therefore, we aimed to understand the roles of TLR signaling in FRC pathobiology during sepsis. FALC cells were isolated from mesenteric adipose tissue in wild-type mice before and after cecal ligation and puncture (CLP). The transcriptomic profile of FALC cells were assessed using single cell RNA sequencing. Notably, FRCs were a major population of FALC cells (50 +/− 10.2 % in control, 30 +/− 8.6% in CLP). One population of FRCs were identified in control mice, and two populations of FRCs were identified in CLP mice. According to gene set enrichment analysis, FRCs after CLP are enriched in gene expression associated with inflammatory response and chemotaxis. Interestingly, activation of TLR4 (LPS) and TLR3 (Poly I:C) signaling in mesenteric adipose tissue derived FRCs significantly increased the expression of chemokines known to attract neutrophils (Cxcl2 and Cxcl5), monocytes (Cxcl3), and lymphocytes (Cxcl13 and Ccl20), while activation of TLR9 (ODN1518) significantly decreased these chemokine gene expressions. Importantly, we found similar regulatory effects of TLR3, 4, and 9 on chemokine production in human adipose tissue-derived FRCs. Together, our results indicate that TLRs plays critical roles in regulating chemokine production by FRCs. These data form a knowledge basis upon which to design new therapeutic strategies of FRC-based treatments for sepsis.
Astragaloside IV, the major bioactive component of Astragalus membranaceus (Fisch.) Radix, attenuates airway inflammation by modulating Th2 cytokines, STAT6 and ROR-γτ transcription factors in an asthmatic mouse model
Authors: Shen Chao-Bin , Gu Yan-Ni , Wang Song , Yu Lan 
Published: January 2023

Abstract

OBJECTIVE
Astragaloside IV (AS-IV), the major bioactive component of Astragalus membranaceus (Fisch.) Radix, possesses anti-inflammatory, regular immunological balance and other pharmacological properties. Although Astragalus is associated with immunoregulatory functions of allergic diseases, the pathophysiological mechanisms of AS-IV action in allergic inflammatory lung disease have not been examined. This study aims to explore the mechanisms of how AS-IV suppresses airway inflammation in bronchial asthma by inhibiting the inflammatory cytokines and transcription factors pathway.

METHODS
A total of 40 BALB/c male mice were selected and divided into control, asthma, AS-IV and dexamethasone groups. Ovalbumin-induced mouse asthma model was established. HE staining were conducted to observe the pulmonary pathological changes. ELISA was adopted for the levels of IFN-γ, IL-5, IL-13, IL-17A and TGF-β, qRT-PCR for the transcription factors mRNA expressions of GATA-3, STAT6, T-bet, RORγt, and Foxp3.

RESULTS
Compared with the control group, the asthma group had irregular tissue structure and severe inflammation, increases in maximal pulmonary resistance. AS-IV strongly suppressed levels of Th2 cytokines IL-5 and IL-13 in lung homogenate, but it upregulated T-bet and Foxp-3 mRNA expression in lungs. AS-IV exerted immunomodulatory effects through downregulation of STAT6, RORγt and GATA-3 expression.

CONCLUSION
These results suggest that the anti-asthmatic activity of AS-IV may occur by the suppression of IL-5, and IL-13 production through inhibition of the STAT6 and RORγt signaling pathways. Our results suggest that AS-IV can be a novel therapeutic component for the treatment of allergic asthma.
PGD2/DP1 signaling deficiency ameliorates experimental autoimmune encephalitis
Authors: Zheng Jian , Perlman Stanley 
Published: January 2023

Abstract
D-prostanoid receptor 1 (DP1) is a myeloid cell-expressing receptor of prostaglandin D2 (PGD2), the most abundant prostaglandin in the brain. PGD2/DP1 signaling, which triggers G protein activation and cAMP production, is associated with neuroprotection after ischemia, astrogliosis and demyelination in mice. In our previous study, PGD2/DP1 signaling was found to suppress mouse hepatitis virus (MHV)-induced central nervous system (CNS) inflammasome activation through up-regulating PYDC3 expression in CD11b+ cells. In this study, we now investigated the role of PGD2/DP1 signaling in active experimental autoimmune encephalitis (EAE). In contrast to their enhanced susceptibility to virus-induced CNS inflammation, DP-1−/− mice showed resistance to MOG35–55 peptide-induced EAE, which was characterized by milder demyelination and improved remyelination compared to wild type mice. The amelioration of CNS injury resulted from less infiltration of leukocytes and of activation of microglia and macrophages in the brain and spinal cord. On the other hand, in draining lymph nodes (DLN) of immunized DP-1−/− mice, myeloid cells (macrophages, neutrophils and dendritic cells (DCs)) exhibited highly pro-inflammatory phenotypes, which correlated with activation-induced apoptosis of MOG35–55 peptide-specific T cells. Finally, conditional deletion of DP-1−/− in either microglial (CX3CR1+ cells) or macrophage/monocyte/granulocyte (Lyz2tm1+ cells) failed to ameliorate EAE, suggesting involvement of a different DP1-expressing cell. Ongoing research is directed at determining this critical cell type.
GTPase-activating protein (RASAL1) associates with ZAP-70 of the TCR and negatively regulates T-cell proliferation and anti-tumor immunity
Authors: Rudd Christopher E , Thaker Youg Raj , Raab Monika , Strebhardt Klaus 
Published: January 2023

Abstract
T-cell activation is needed for responses to antigen and controls responses to foreign antigen and cancer neo-antigens in immunotherapy. The full range of signaling events that inhibit T-cell activation and limit anti-tumor reactivity is unclear. Previous studies have identified the importance of phosphatases and E-3 ligases as inhibitors of activation. In this study, we show by a combination of tandem affinity chromatography, co-precipitation and proximity ligation analysis (PLA) that RASAL1, a novel GTPase-activating protein (GAP), binds to ZAP-70 of the TCR complex and inhibits anti-CD3 activation of ERKs and proliferation in T-cells. RASAL1 inhibited via two pathways where it binds and inhibits ZAP-70 activity, and acts as a GAP to inhibit the p21ras-ERK pathway. As a negative regulator, its expression is induced as a consequence of T-cell activation, where it reduced in vitro responses to anti-CD3 and to antigenic peptides presented by dendritic cells (DCs), while having no effect on T-cell dwell times. Further, we show that siRNA knock-down of RASAL1 expression increased in vivo CD4+ T-cell responses to peptide antigen while reducing the pulmonary metastasis of B16 melanoma and the growth of solid EL-4 lymphoma tumors. This anti-tumor effect was accompanied by a marked increase in CD8+ tumor-infiltrating T-cells (TILs) expressing effector molecules granzyme B (GZMB) and interferon γ-1 (IFNγ1). These findings identify RASAL1 as a new negative regulator of T-cell activation and tumor immunity.
FOXP3, CD48 and autophagy confer the protection of CD4 and CD8 human T cells from T cell receptor restimulation-induced cell death
Authors: Voss Kelsey , Lott Nathaniel M , Lake Camille , Bauman Bradly M , Dorjbal Batsukh , Luthers Christopher R , Arjunaraja Swadhinya , Dalgard Clifton L , Snow Andrew L 
Published: January 2023

Abstract
The proliferation and contraction of activated effector T cells must be carefully coordinated to maintain immune homeostasis. This is achieved in part through restimulation-induced cell death (RICD), a pre-programmed apoptosis program triggered by antigen restimulation through the T cell receptor (TCR). Forkhead box P3 (FOXP3)+ regulatory T cells (Tregs) also constrain conventional T cell (Tcon) responses, but can resist RICD themselves despite frequent TCR stimulation. We previously showed that FOXP3 protects Tregs from RICD by suppressing SLAM-associated protein (SAP), a key adaptor protein that amplifies TCR signal strength. Mysteriously, FOXP3 expression is also transiently induced in human Tcons after activation, with a kinetic expression profile that correlates inversely with acquired RICD sensitivity. Hence we asked whether FOXP3 protects expanding human effector T cells from premature RICD by modulating SAP expression. Our results show that although siRNA-mediated FOXP3 knockdown sensitizes early effector CD4 and CD8 T cells to RICD, SAP expression remains unaffected. Unlike late stage effector T cells, a low level of RICD in expanding Tcons was entirely dependent on de novo transcription, and knockdown of SAP failed to reduce death. Subsequent RNA-Seq analyses revealed that CD48, a SLAM family receptor, was markedly reduced upon FOXP3 knockdown. Blockade or knockdown of CD48 also increased RICD in CD4 and CD8 T cells. We now show that CD48 protects early effector T cells both by promoting autophagy and upregulation of pro-survival genes such as BATF. These findings implicate FOXP3 as the central governor of a distinct transcriptional program that promotes RICD resistance early in the effector T cell response.
PD-L2 generates a signal through the PD-1 co-receptor distinct from that of PD-L1
Authors: Srinivasamani Anupallavi , Liu Qinying , Curran Michael 
Published: January 2023

Abstract
Immune checkpoint blockade of the PD-1/PD-L1/PD-L2 signalling axis yields potent anti-tumor responses by disinhibiting T cell effector function. Mouse and human data demonstrating an inhibitory role for PD-L1 has resulted in FDA approval of anti-PD-L1 antibodies; however, PD-L2 remains sparsely studied despite being the higher affinity of the two ligands for PD-1. Recent findings demonstrate that PD-L2 is widely expressed by human malignancies. PD-L1 and PD-L2 have also been shown to induce distinct conformational changes on engaging human PD-1.
We utilized a Jurkat T cell based bioluminescent assay of T cell activation and PD-1 inhibition to determine the unique mechanism of action of human PD-L2. In this system, human PD-L2 generates a solely co-inhibitory signal, but at reduced inhibitory potential relative to PD-L1. We find that unlike murine PD-L2, human PD-L2 appears to have a dedicated co-inhibitory function as we find no significant engagement of the human homolog of its murine co-stimulatory partner RGMb. Reverse phase protein array analysis of human PD-L1 and PD-L2 engagement of PD-1 on Jurkat T cells revealed significant differences in downstream T cell signalling generated by each ligand. We also find that human PD-L1 and PD-L2 have disparate impacts on proliferation wherein PD-L2 supports a preferential arrest of T cells in the S-phase of the cell cycle. We observed that combination blockade of PD-L1 and PD-L2 improves on the blockade of PD-L1 alone resulting in increased production of IL-2 and IFNγ in primary human mixed lymphocyte reactions. Our findings address critical gaps in our knowledge about the basic function of PD-L2 and will inform future attempts to manipulate the PD-1 co-inhibitory circuit.
Indole-3-carbinol ameliorates colonic inflammation in DSS-treated, Helicobacter muridarum-infected mice
Authors: Alkarkoushi Rasha Raheem , Singh Udai P. , Chatzistamou Ioulia , Bam Marpe , Hui Yvonne , Nagarkatti Mitzi , Nagarkatti Prakash , Testerman Traci L. 
Published: January 2023

Abstract
Enterohepatic Helicobacter species are epidemiologically linked to increased inflammatory bowel disease; however, little research has been done to elucidate potential contributions of individual species. We hypothesized that Helicobacter muridarum (Hm) would alter the course of DSS-induced colitis and the response to indole-3-carbinol (I3C), an anti-inflammatory phytochemical. We treated Hm-infected C57BL/6 mice with1% DSS +/− 40 mg/kg I3C and measured inflammatory biomarkers. We found that H. m exacerbated DSS-induced colitis and increased the percentage of Th17 cells in the mesenteric lymph nodes and spleen and increased IL-17 in colonic tissue compared to the DSS group. Also, we found that Hm bacteria itself produced inflammation and pathology. I3C, on the other hand, ameliorated colitis and shifted the Treg/Th17 balance in DSS+H.m-infected mice. We found that I3C treatment of DSS + H.m-infected mice decreased the expression of pro-inflammatory IL17 and RORC as well as increased anti-inflammatory Foxp3 when compared to the untreated group. The decreased expression of RORC correlated with increased miR-let7a-2 and miR-29a-3p expression and increased FoxP3 correlated with decreased miR-874 expression following I3C treatment. Moreover, I3C reduced the abundance of certain taxa, such as Clostridiales, Actinobacteria, and Erysipelotrichales, and increased the abundance of Ruminococcus. In summary, H. muridarum causes baseline inflammation and exacerbates colitis via microRNA-mediated increases in Th17 cells, while I3C ameliorates colitis via increased Treg populations.
MiR-146a is a negative regulator of IL-33-stimulated mouse mast cells
Authors: Kee Sydney Ann , Taruselli Marcela T , Ryan John J , Qayum Amina Abdul 
Published: January 2023

Abstract
Interleukin-33 (IL-33) is an inflammatory cytokine that promotes allergic disease by activating ILC2, Th2, and mast cells. IL-33 is increased in asthmatics, and its blockade suppresses asthma-like inflammation in mouse models. The IL-33 receptor, ST2, shares signaling cascades with the TLR family, but homeostatic control of ST2 function is poorly understood. MicroRNA-146a (miR-146a) is induced by LPS and suppresses TLR4 signaling in macrophages. Therefore, we explored whether miR-146a has a role in IL-33 signaling. IL-33 induced cellular and exosomal miR-146a expression in mouse bone marrow derived mast cells (BMMC). Induction required MyD88, Akt, and NFkB, since antagonizing these pathways decreased miR-146 expression. BMMC transfected with a miR-146a antagomir or derived from miR-146a KO mice showed enhanced cytokine expression in response to IL-33, suggesting that miR-146a is a negative regulator of IL-33-ST2 signaling. Our data further suggest that miR-146a may act by targeting IRAK proteins, because mir-146a KO BMMC have increased TRAF6, IRAK1, and IRAK4 expression. In vivo, miR-146a expression in plasma exosomes was elevated after intraperitoneal injection of IL-33. Also mast cell deficient c-Kitw-sh mice acutely reconstituted with miR-146a KO BMMC intraperitoneally had elevated plasma IL-6 levels in comparison to their WT counterparts after IL-33 challenge. These results support the hypothesis that miR-146a is a feedback regulator of IL-33-mediated mast cell functions associated with allergic disease.
Transcription factor Blimp-1 regulates sebocyte homeostasis and cytokine production
Authors: Hung Kuo-Hsuan , Wu Yen-Fei , Lin Kuo-I 
Published: January 2023

Abstract
Blimp-1, encoded by Prdm1, is a master transcriptional factor that governs the differentiation fate of many cell types, including epidermal keratinocytes. Previous results from our laboratory showed that inducible deletion of Prdm1 in mouse epidermis spontaneously induces skin inflammation. Epidermis composes of not only epidermal keratinocytes, but also epidermal appendages, including hair follicles, sebaceous glands and sweat glands. Sebaceous glands release the “oil” contents that lubricate the skin. Our previous results also showed that Blimp-1 is required for the maintenance of the homeostasis of terminally differentiated sebocytes. Here, we aim to investigate the potential function of Blimp-1 in inflammation and lipid metabolism in sebocytes. We depleted Blimp-1 by siRNA in SZ95, the immortalized human sebocyte cells. We found accumulated and enlarged lipid droplets in Blimp-1 depleted cells. Consistently, gas chromatography–mass spectrometry (GC-MS) analyses showed that the levels of several long-chain fatty acids, including 1,3-dipalmitoyl-2oleoylglycerol, 1-palmitoyl-2oleoyl-3-lineoleoyl-rac-glycerol, and triolein, were accumulated in Blimp-1-depleted SZ95 cells, linking with the significant increases in the production of pro-inflammatory cytokines, including IL-1β, IL-6, IL-8 and IL-18. Thus, Blimp-1 served as a pivotal mediator in the regulation of the inflammatory responses in epidermis, likely also through affecting the lipid metabolism and cytokine production in sebocytes.
Using single-cell RNA-seq to lineage trace effector to memory transitions in CD4+ T cells during malaria
Authors: Soon Sioe Fei Megan , Engel Jessica , Lee Josh , James Kylie , Lonnberg Tapio , Svensson Valentine , Teichmann Sarah , Haque Ashraful 
Published: January 2023

Abstract
Hallmark features of adaptive CD4+ T-cells include differentiation into multiple effector T helper (Th) fates and subsequent emergence of memory states. Due to the heterogeneous nature of CD4+ T-cells, determining possible developmental relationships between effector and memory states in vivo has remained a challenge. Previously we employed single-cell RNA-sequencing (scRNA-seq) to delineate the molecular trajectories of Plasmodium-specific TCR transgenic CD4+ T cells during the first week of experimental malaria. We observed a fate bifurcation as cells progressed from an intermediate, activated state to either effector Th1 or T follicular helper (Tfh) cells. My current project tests the hypothesis that CD4+ Th cells directly convert into memory CD4+ T cells during malaria, and aims to define the underlying transcriptomic processes. Tracking endogenous TCR sequences via TraCeR analysis firstly confirmed that sibling clones populated both Th1 and Tfh fates. Next, by comparing transcriptomes, and performing computational lineage tracing of the scRNA-seq data, we observed a direct transition from Th1 and Tfh effector states to memory states. This was characterised by gradual transcriptomic quiescence during the first month of infection, as well as transcriptomic coalescence of Th1 and Tfh fates, but with retention of Th1/Tfh bifurcated structure in memory cells. Finally, premature cure of infection with anti-malarial drugs altered transcriptomic pathways taken by cells towards those with better Th1 recall and germinal centre Tfh phenotypes, respectively. Thus, by examining transcriptional dynamics using scRNA-seq, I am tracing the molecular pathways taken by effector CD4+ T cells towards functional memory states.
Th2 cytokines and specific donor alloantigen activated CD4+CD25+T cells reverse chronic rejection: role of IL-4 and IL-5 in promoting antigen-specific Treg
Authors: Hall Bruce Milne , Rakesh Prateek , Tran Giang , Hall Rachael , Bedi Sukandeep , Robinson Catherine Margaret , Sharland Alexandra , Wang Chaunmin , Hodgkinson Suzanne Jean , Verma Nirupama Darshan 
Published: January 2023

Abstract
Naïve CD4+CD25+Foxp3+T regulatory cells (tTreg) activated by specific alloantigen (Ag) and IL-4 express IL-5Ralpha. We examined if IL-5 treatment activated alloAg specific Treg to prevent chronic rejection in F344 rats grafted with Lewis hearts. 5000units rIL-5 (rIL-5Rx) was given daily from 7d after grafting when rejection had started. Changes in CD4+CD25+T cells were assessed by FACS, RT-PCR of Il5ra and response to alloAg in MLC.
Sham Rx rats fully rejected their grafts by 28d while IL-5Rx for 10d reversed rejection and grafts survived 60d (p&lt;0.01). There were rejection episodes after stopping IL-5 but continued IL-5Rx reduced this. Pre-treatment with anti-CD25 or anti-IL-4 mAb abolished the benefit of rIL-5Rx, all grafts rejected by 28d. IL-5 treated hosts had increased CD4+CD25+T cells, 6–8% vs 3–4% in controls. After 10d of rIL-5Rx, host CD4+CD25+T cells responded to Lewis but not to F344 or third-party PVG alloAg in MLC, showing activation of alloAg-specific Treg. CD4+CD25+T cells from rats treated for 50d with rIL-5 had more il5ra, remained FOXP3+ and in MLC rIL-5 enhanced responses to Lewis but not other alloAg. These findings are consistent with IL-4 and alloAg activating tTreg to induce Ag-specific Treg that suppress rejection.
To demonstrate rIL-4 and specific alloantigen activated naïve tTreg to suppress rejection, these cells were prepared ex vivo. 5×106 of these IL-4 alloAg activated tTreg, given after rejection commenced, reversed rejection. 5×106 fresh naïve tTreg or 5×106 tTreg activated by third-party PVG alloAg had no effect on rejection.
IL-5 prevented heart graft rejection through hosts’ CD25+Treg that had been activated by alloAg and IL-4. IL-5 therapy may have potential to prevent chronic allograft rejection.