bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Y-chromosome factor impairs iNKT cell development (85.15)
Authors: Toussaint Leon , Terrizzi Stephanie , Teuscher Cory , Brossay Laurent 
Published: January 2023

Abstract
Invariant Natural Killer T (iNKT) cells are a fairly recently discovered unique subset of T lymphocytes. These granular cells are derived from the thymus and share properties of both NK and T cells. iNKT cell development is unique from mainstream T cell selection and the polygenic factors that influence NK T cell ontogeny are still unclear. Previous studies done in our laboratory has shown the absence of iNKT cells in male B6.IFN-αβR1-/- mice. Analysis of the iNKT cell compartment in a variety of mice demonstrated that the deficiency was linked to the Y-chromosome but independent of IFN-αβ. Here, we generated wild-type male B6 mice carrying the YNKT-chromosome as well as male B6.IFN-αβR1-/- mice that do not carry the YNKT-chromosome. We found that wild-type B6 (YNKT) male mice have a strong decrease in iNKT cell frequency. In contrast, the B6.IFN-αβ R1-/- male mice have a relatively normal repertoire, confirming that the deficiency is linked to the Y-chromosome and is independent of IFN-α/β In addition, preliminary data using two different strains of B6 consomic mice for the Y-chromosome show that they have a normal iNKT cell repertoire. This suggests that a consomic Y chromosome is not sufficient to influence iNKT cell development. We are currently investigating whether the phenotype observed is due to a Y chromosome mutation or an epistatic interaction with other genes. This work was supported by the National Institutes of Health Research Grant AI46709.
Glycerol-3-phosphate acyltransferase-1 Alters Thymic Development in Mice (85.16)
Authors: Jolly Christopher A , Gulvady Apeksha , Collison Lauren W 
Published: January 2023

Abstract
Our lab has recently shown that T-lymphocyte function ex vivo from glycerol-3-phosphate acyltransferase-1 (GPAT-1), first enzyme in de novo glycerophospholipid biosynthesis, knockout mice is similar to aged T-lymphocytes. In order to determine the mechanism(s) for this observation, we examined thymic development in GPAT-1 KO mice. Thymi were weighed then thymocytes isolated for determination of proliferation and thymic subset proportions. We found that the thymi from GPAT-1 KO mice were 30% smaller than the wild type controls and thymocyte proliferation was reduced. Furthermore, the thymic single positive CD4 and double negative subset proportions were increased while the double positive population was decerased. The changes in thymic weight and thymocyte subsets are most likely not linked to altered fetal thymic development since thymic weights from 3 week old mice were identical to that seen in wild type controls. Since T-lymphocyte GPAT-1 activity is reduced in aged T-lymphocytes these data give insight into a novel mechanism by which aging may alter thymic development and subsequent peripheral T-lymphocyte function. This work was supported by NIH AG20651 (CAJ).
Interplay between pre-TCR, CXCR4 and laminin10/11 during thymic β selection (85.8)
Authors: Trampont Paul C , Tosello-Trampont Annie-Carole , Shen Yueli , Duley Amanda K , Bender Timothy P , Sutherland Ann B , Littman Daniel R , Ravichandran Kodi S 
Published: January 2023

Abstract
The βselection checkpoint during thymocyte development is a key step when immature thymocytes at double negative 3 (DN3) stage are selected to progress to the DN4 stage and beyond. While the role for the pre-T cell receptor (pre-TCR) during βselection has been established, how other receptors contribute to βselection is not well understood. Here, we identify a previously unrecognized role for CXCR4 during βselection using mice with a conditional loss of CXCR4 expression in DN thymocytes. CXCR4 physically and functionally associates with the pre-TCR and influences βselection via at least three mechanisms: regulating steady-state localization of immature thymocytes within thymic subregions, providing survival signals, and influencing efficient thymocyte proliferation post-β selection. We also show co-localization of SDF-1α, laminin 10/11 and DN3 thymocytes at the subcortical thymic regions, where the βselection events are thought to take place. We characterize the adapter protein ShcA and ERK kinase as functionally relevant signaling molecules downstream of CXCR4/pre-TCR/integrins. These data identify CXCR4 as a novel costimulator during βselection that functions together with pre-TCR and integrin ligands to orchestrate thymic development. Taken together, these data identify a novel interplay between the pre-TCR, CXCR4 and integrin receptors in regulating the βselection checkpoint.
Altered CD4/CD8 cell fate decision in the absence of MAZR due to redirected differentiation of MHC class I-restricted thymocytes (85.9)
Authors: Sakaguchi Shinya , Hombauer Matthias , Naoe Yoshinori , Bilic Ivan , Schebesta Alexandra , Taniuchi Ichiro , Ellmeier Wilfried 
Published: January 2023

Abstract
Cell fate specifications during thymocyte differentiation are linked with the tightly controlled expression of CD4 and CD8. We have previously identified that the transcriptional regulator MAZR is an important regulator of the activation of the Cd8ab gene complex during the DN to DP transition. To investigate the role of MAZR in more detail, MAZR-/- mice were generated. MAZR-/- mice were smaller in size and were born at reduced mendelian frequency. MAZR-/- DN thymocytes did not show premature expression of CD8, indicating that the deletion of MAZR is not sufficient to activate CD8 expression in DN cells. However, variegated CD8 expression in DP thymocytes of Cd8 enhancer E8I,E8II doubly deficient mice was dramatically reduced in the absence of MAZR. In addition, we observed elevated CD4/CD8 ratios in thymocytes and in peripheral T cells of MAZR-/- mice. Using MHC class I-restricted TCR transgenic mice, we demonstrated that the altered CD4/8 ratio in MAZR-/- mice was, in part, due to redirected differentiation of a fraction of MHC-class I restricted thymocytes into the CD4 lineage. Thus, our data provide genetic evidence that MAZR controls CD8 expression during thymocyte development. In addition, our results may indicate that MAZR is part of the transcription factor network that controls CD4/CD8 cell fate decisions of DP thymocytes.
Supported by the Austrian Science Fund (P19930, SFB-F2305 and START Program Y-163).
MicroRNA profiling of thymocytes undergoing stress-induced atrophy (86.10)
Authors: Medeiros Jennifer J , de la Morena Maria Teresa , van Oers Nicolai S.C. 
Published: January 2023

Abstract
Acute thymic atrophy occurs in a number of clinical situations including pregnancy, irradiation, immunosuppressive therapy, and bacterial infections. Lipopolysaccharide (LPS), a component of Gram-negative bacteria, can induce thymic atrophy within 48 hrs. While cytokines, corticosteroids, and TNF can mediate various aspects of thymic atrophy, little is known about the possible role of microRNAs. MicroRNAs (miRNAs) are a class of non-coding, small RNAs that regulate gene expression in many biological systems including the immune system. To assess whether miRNAs might regulate LPS-induced thymic atrophy, we performed miRNA profiling. C57BL/6 mice were injected with LPS and RNA was extracted from the thymus at various time points post-injection. LPS induced an overall decrease in thymic cellularity within 72 hours, with a significant decrease in the CD4/CD8 double positive population (p=&lt;0.05). Preliminary microarray analysis yielded 8 and 6 unique miRNAs that were up- and down-regulated, respectively. We are currently confirming the microarray data with Northern blots probing for selected miRNAs. MiRNA expression patterns unique to different diseases or disorders are crucial to not only elucidating the role of miRNAs in the innate and adaptive immune response, but also in developing novel therapeutic treatments.
Leptin protects against endotoxin-induced thymic remodeling (86.9)
Authors: Gruver Amanda L , Sempowski Gregory D 
Published: January 2023

Abstract
Thymic atrophy is highly inducible by stress. While prolonged thymus atrophy can contribute to T cell deficiency, no treatment is available to enhance thymopoiesis during stress events. Leptin deficiency in mice results in chronic thymic atrophy and suppressed immunity, suggesting a role for leptin in regulating immune homeostasis. Specific roles however for intrathymic leptin signaling are currently undefined. We report here the novel finding that leptin receptor expression in the thymus is not present on developing thymocytes, but restricted to medullary thymic epithelial cells. We found leptin protected against endotoxin-induced acute thymic atrophy by preventing the loss of medullary thymic epithelial cells, protecting DP thymocytes from endotoxin-induced apoptosis, and increasing proliferation in DN thymocytes. We demonstrated that these thymoprotective effects are mediated through a leptin receptor isoform b-specific mechanism, and that leptin treatment increased thymic steady-state mRNA levels for IL-7. Taken together, our data suggested a novel intrathymic role for leptin in indirectly modulating thymocytes during thymic injury via a direct effect on medullary thymic epithelial cells. Overall, these findings support the use of leptin as a potential therapeutic to enhance T cell reconstitution in settings of stress-induced thymic atrophy. Supported by AG025150.
PKCbeta-II expression promotes PKD2 activation in Malignant B Lymphocytes (88.19)
Authors: Sather Blythe D , Mikhalap Svitlana V , Moreno-Garcia Miguel E , Sommer Karen , Shlapatska Larysa M , Sidorenko Svetlana P , Rawlings David J 
Published: January 2023

Abstract
Development of therapies for diffuse large B-cell lymphomas (DLBCL) requires a precise knowledge of signaling aberrations essential for tumor development. In normal B cells, the B cell receptor (BCR) initiates intracellular signals crucial for the survival and proliferation and may contribute to pathogenesis. Previous studies identified PKCbII, PKD1 and PKD3 as key DAG regulated downstream targets of BCR induced signaling and many refractory DLBCL tumors exhibit elevated expression of PKCbII. This correlates with activation of the PKCbII-NF-kB signaling cascade; and inhibition of PKCbII blocks the survival of these tumors in vitro. In this study, we show PKD2 is the predominant PKD family protein that is expressed and activated in response to BCR engagement in normal and malignant human B cells. Following BCR engagement in naïve B lymphocytes, activated PKD2 initially co-localizes with the BCR and then shuttles from the cytoplasm to the nucleus. We show using immunohistochemistry that localization and activation of PKD2 in DLBCLs correlates with the level of PKCbII expression. Using several models, we show that while PKCbII is not required for BCR-mediated PKD2 phosphorylation, increased expression of PKCbII promotes both PKD2 activation and class II HDAC phosphorylation. Finally, we show that PKD2 and a key substrate for PKCbII in B cells CARMA1, synergize to drive antigen receptor-triggered NF-kB transcriptional activity. Together, our data imply that PKD2 and PKCbII may work in concert to control transcriptional events regulating B cell survival.
IMMUNE-DEFICIENT MOUSE STRAINS DISPLAY MARKED VARIABILITY IN GROWTH OF HUMAN MELANOMA LUNG METASTASES (88.6)
Authors: Carreno Beatriz M. , Garbow Joel R , Kolar Grant R , Jackson Erin N. , Engelbach John A , Becker-Hapak Michelle , Carayannopoulos Leonidas N , Piwnica-Worms David , Linette Gerald P 
Published: January 2023

Abstract
Immune-deficient mice are widely used in cancer research to study human cancer biology and evaluate new therapeutics. No comprehensive study has been published documenting differences in human tumor engraftment among immune-deficient strains. Using RhoC-expressing human (A375) melanoma cells, we evaluate scid, NOD-scid (NS), NOD-scid β2mnull (NSB), and NOD-scid IL2Rγnull (NSG) as xenograft tumor recipients. Bioluminescence, magnetic resonance imaging and histopathology were employed to monitor serial tumor growth. Melanoma metastases growth is delayed and variable in scid, and NS mice. In contrast, NSB and NSG mice show rapid tumor engraftment, although tumor growth is variable in NSB mice. NK cells were detected in all strains except NSG, and in vitro activated scid, NS and NSB NK cells kill human melanoma lines and primary melanoma cells. Expression of human NKG2D ligands, MICA and MICB, renders melanoma susceptible to murine NK cell-mediated cytotoxicity and killing is inhibited by antibody blockade of murine NKG2D. Murine NKG2D recognition of MICA/B is an important receptor-ligand interaction employed by NK cells in immune-deficient strains to limit engraftment of human tumors. The absolute NK deficiency in NOD-scid IL2Rγnull animals makes this strain an excellent recipient of melanoma and potentially other human malignancies.
Calcineurin Ab deficiency causes defective Treg-cell generation and enhanced effector T-cell differentiation (89.13)
Authors: Bommireddy Ramireddy , Chen Hwudaurw , Gard Connie , Molkentin Jeffery D. , Doetschman Tom 
Published: January 2023

Abstract
Calcineurin (CN), a protein phosphatase activated by Ca2+-calmodulin, is involved in activation of NFAT by its dephosphorylation. CN inhibitors such as cyclosporine A (CsA) and FK506 are potent inhibitors of T-cell responses and are commonly used to prevent graft rejection. Consistently, CNAβ-deficient mice exhibit defective thymocyte maturation in young mice. However, T cells undergo spontaneous activation in older Cnab-/- mice, which develop splenomegaly, thymomegaly, hepatomegaly and succumb to metastatic B-cell lymphomas. We have also observed that FOXP3+ Treg cells are decreased while mature activated CD4+ and CD8+ T cells (CD62L-CD44+) are increased in Cnab-/- mice compared to age-matched control mice. These data show that CNAβ is important for the development and homeostasis of mature T cells and Treg cells. Cytokine profile analysis revealed that CNAβ signaling is required to inhibit proinflammatory cytokines (IL-4, IL-10, IL-17 and IFNγ) by TGFβ1 and TGFβ1 induced FOXP3 expression in T cells, suggesting that CNAβ signaling is required for Treg-cell generation. The data suggest that in the absence of CNAβ, a defective T-cell regulatory environment leads to accumulation of activated T cells which produce proinflammatory cytokines and cause inflammation and cancer.
Grant support: This study was supported by NIH AI067903 and CA84291 to TD, and IRG7400128 to RB.
Deriving murine steady state dendritic cells in the presence of a potent AhR ligand produces modulatory dendritic cells (89.18)
Authors: Simones Tom , Shepherd David M. 
Published: January 2023

Abstract
TCDD is the prototypical aryl hydrocarbon receptor (AhR) agonist and a potent immunotoxicant. However, the specific mechanisms underlying the immunomodulatory effects of TCDD are currently undefined. TCDD adversely affects a number of immune cells including DCs. We hypothesize that TCDD alters the differentiation of steady state DCs and causes the formation of modulatory DCs. To test this hypothesis, steady state bone marrow-derived dendritic cells (BMDCs) were grown in the presence of Flt3 ligand, and vehicle or TCDD. Flt3 ligand growth factor is commonly used to derive BMDCs representative of non-inflammatory immature steady state DCs. Growth in TCDD caused decreased expression of both CD11c and MHC II and increased the basal CD86 expression as determined by flow cytometry. An increased frequency of TCDD-derived BMDCs expressed MHC II, CD86 and CD54 following LPS or CpG stimulation as compared to vehicle-treated control BMDCs. In response to LPS or CpG, TCDD-BMDCs produced less IL-6 and TNFα. TCDD-BMDCs also up regulated indoleamine 2, 3-dioxygenase 2 (IDO2) mRNA levels, while IDO1 mRNA levels remained unchanged. IDO1 and IDO2 are thought to play a role in Treg generation and immune suppression. Altogether these data suggest that TCDD-BMDCs display immune regulatory properties attributable to a novel modulatory DC population. This research was supported by grants ES013784 and RR17670.
The naturally arising FoxP3+ CD4+ regulatory T cells preferentially respond to weak TCR stimulation due to constitutive nuclear translocation of NFAT (89.20)
Authors: Guo Xiaohua , Jensen Peter , Chen Xinjian 
Published: January 2023

Abstract
Constituting a small fraction of CD4 T cells, the naturally arising FoxP3+ CD4+ Tregs are potent suppressors required for maintenance of self-tolerance. Despite their high potency in suppressing autoimmunity, Tregs appear not to suppress protective immunity against common microbial infections, as a Treg-intact host is fully immunocompetent. How Tregs suppress certain but not all immunity is incompletely understood since the signaling pathway selectively activating Tregs has not yet been determined. We recently reported that weak allo-stimulation preferentially activates allo-reactive Tregs. Here we report that Tregs preferentially respond to all weak TCR stimulation including Ag-specific or anti-CD3-mediated TCR stimuli. In search for the underlying mechanism, we found that in freshly isolated Tregs a major fraction of NFAT molecules but not of the other two major transcription factors NF-κB and AP-1 was localized in the nucleus. Resting or treating Tregs ex vivo with the calcineurin inhibitor cyclosporine A (CsA) did not alter NFAT nuclear localization. Consistently, CsA failed to inhibit anti-CD3/CD28-induced proliferation of Tregs in cultures supplemented with IL-2. Similarly, PMA that activates NF-κB and AP-1 but not NFAT selectively induced proliferation of Tregs but not Tcons when used alone without ionomycin. Our results together with the data of others demonstrate that NFAT, through interacting with FoxP3, is constitutively located in the nucleus of Tregs, and its constitutive nuclear localization not only endows the Tregs with an anergic phenotype and capacity to suppress, but also the ability to preferentially respond to weak TCR stimulation or stimuli that activate NF-κB and AP-1 but not NFAT.
PPARgamma drives conversion of inducible Tregs by stimulating dendritic cell production of retinoic acid (89.23)
Authors: Housley William J , O'Conor Catherine A , Clark Robert B 
Published: January 2023

Abstract
Regulatory T cells are critical in preventing autoimmunity, and peripherally-generated inducible regulatory T cells (iTregs) may also play an important regulatory role. Retinoic acid (RA) has been shown to enhance iTreg generation, and specific subsets of gastrointestinal (GI) dendritic cells (DCs) enhance iTreg generation through production of RA. The factors that regulate DC secretion of RA are unknown. We postulated that the nuclear hormone receptor PPARγ may regulate murine DC production of RA and DC-mediated generation of iTregs. PPARγ ligands are expressed in the GI tract and both down-regulate immune responses and ameliorate murine models of autoimmunity. Using splenic DCs and the synthetic PPARγ ligand Ciglitizone (Cig), we show that PPARγ activation in vitro increases iTreg generation. This increase can be blocked by LE 540, an RA inhibitor, or Citral, an RA synthesis inhibitor, and is associated with an upregulation of mRNA for RA-synthesis enzymes. In vivo administration of Cig also increases splenic DC expression of RA-synthesis genes, and, ex-vivo, these DCs enhance iTreg generation. Finally, the PPARγ-inhibitor GW9662 blocks both the baseline iTreg generation and the Cig-induced increase in iTreg generation. Our results show that PPARγ activation can increase DC RA production and DC-mediated iTreg generation, suggesting a new role for PPARγ in immunoregulation (NIH: 1R56AI072533-01A1).
“Induction” of Regulatory T cell Function is IL-35 and IL-10 dependent (89.35)
Authors: Collison Lauren W , Pillai Meenu R , Chaturvedi Vandana , Vignali Dario AA 
Published: January 2023

Abstract
Regulatory T cells (TR) are believed to suppress naïve effector T cell (TN) proliferation in vitro in a contact-dependent, cytokine-independent manner, based in part on experiments in which TR and TN are separated by a permeable membrane. We show that the production of interleukin-35 (IL-35), a novel inhibitory cytokine expressed by natural TR, increases substantially following contact with TN. Surprisingly, TR were able to mediate potent suppression of TN across a permeable membrane when placed in direct contact with TN in the upper chamber of a Transwell plate. Suppression was IL-35 and IL-10 dependent, as shown by the use of IL-35 or IL-10 deficient TR and IL-10 addition or neutralization. In addition, by utilizing TN that were unable to be activated due to fixation or inappropriate Vβ stimulation, we show that TN activation was required for maximal potentiation of TR suppression. Not only was activation required for maximum potentiation of TR suppression, but TN-derived autocrine IL-10 was also required for maximal suppression. Interestingly, both TN and polarized effector T cells (Th1 or Th2) are capable of potentiating TR suppression in a cell contact independent manner. These data suggest that it is the 'induction' of suppression, rather than the 'function', of TR that is obligatorily contact-dependent. Moreover, they provide evidence that IL-10 is key for maximal regulatory activity, as seen across a Transwell membrane, providing a potential explanation for the previously reported conflicting in vitro and in vivo data.
FOXP3 activation in Treg cells, - atomic level aspects of FOXP3 structure and biochemistry that govern function (89.4)
Authors: Li Bin , Song Xiaomin , Zhou Zhaocai , Wang Qiang , Shen Yuan , Greene Mark I 
Published: January 2023

Abstract
The path by which signaling transduction from the cell surface to the nucleus leads to FOXP3 activation and function is undefined. The additional complexity of creation of an ordered FOXP3 ensemble of transcriptional cofactors on chromatin is not understood. FOXP3 activation in Treg cells may be regulated by extra-cellular stimuli that occur through innate, toll-like and cytokine receptors. Our studies found that TCR receptor and pro-inflammatory cytokine signals including TGF-beta and IL-6 regulate FOXP3 binding to DNA in human CD4+CD25+ Treg cells. Here we report our recent progress in understanding the role of cell surface receptor signals and pro-inflammatory cytokines in regulating biochemical modifications of the FOXP3 molecule altering its activity in Treg cells. We have now determined the biochemical features of how pro-inflammatory cytokines and pharmaceutical agents affect FOXP3 activity, and consequently how they may affect immune responses in human inflammatory disease. Moreover, we also have deduced the atomic structure of large parts of the FOXP3 molecule including the zinc finger and leucine zipper domains. These regions are important for dimerization and oligomerization of FOXP3 as well as interactions with other molecules. Our structural and biochemical studies establish the atomic and molecular basis for understanding human XLAAD/IPEX autoimmune diseases.
Research grants include NIH AI073489-01A1 (M.I.G.) and Nidus Laboratories (B.L., and Z.Z.).