bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activated platelet-mediated induction of CD16 expression and its role in human monocytes
Authors: Lee Su Jeong , Yoon Bo Reum , Kim Bonah , Lee Ga Hye , Kang Yeon Jun , Kang Seong Wook , Lee Eun Bong , Lee Won-Woo 
Published: January 2023

Abstract
Monocytes are important cellular effectors of innate immune defense. In humans, circulating monocytes are heterogeneous and can be divided into three distinct subsets based on CD14 and CD16 expression. The expansion of “intermediate” CD14+CD16+ monocytes is well reported in many chronic inflammatory conditions such as rheumatoid arthritis (RA). However, the mechanism underlying induction of CD16 and the role of CD16 in CD14+CD16+ monocytes remain unclear. ADP-treated autologous platelets induced CD16 expression by highly purified “conventional” CD14+CD16− monocytes. Given that platelet activation causes the release of several soluble factors, we examined an effect of cytokines, which are involved in monocyte-platelet aggregation (MPA), on CD16 induction. MPA led to significantly increased production of TGF-β and IL-6. Exogenous TGF-β and IL-6 in platelet-free culture induced CD16 expression, whereas neutralizing antibodies for TGF-β and IL-6 largely suppressed CD16 induction. Furthermore, selective inhibitors of SMAD3 and STAT3 reduced CD16 expression, indicating a critical role of TGF-β and IL-6 for CD16 induction by CD14+CD16− monocytes. Functionally, induced CD16 participates in IgG-mediated phagocytosis and the level of CD16 expression in activated platelet-treated monocytes is correlated with uptake of beads coated with FITC-labeled IgG. Lastly, CD14+CD16− monocytes treated with activated platelets differentiate into M2-like macrophage. Our findings suggest an important role of activated platelets for modulating phenotypical and functional features of monocytes in humans. This will be helpful for understanding immunological role of CD14+CD16+ in chronic inflammatory diseases.
Immune sensing of synthetic, bacterial and protozoan RNA by TLR8 requires coordinated processing of RNA substrates by RNaseT2 and RNase2
Authors: Bartok Eva Sarah , Ostendorf Thomas , Zillinger Thomas , Andryka Katarzyna , Guimaraes Thais Marina , Schmitz Saskia , Marx Samira , Bayrak Kübra , Linke Rebecca , Salgert Sarah , Grasser Tatjana , Baersachs Sonja , Hübner Marc , Soltesz Leon , Kettwig Matthias , Nastaly Maximilian , Roehl Ingo , Henneke Marco , Barchet Winfried , Gärtner Jutta , Schlee Martin , Hartmann Gunther 
Published: January 2023

Abstract
Human TLR8 is an essential sensor of bacterial RNA which induces proinflammatory and Th1 cytokines. Crystallography revealed that TLR8 binds both uridine and short single-stranded RNA, but the RNases that process the RNA are still unknown. Herein, we demonstrate that two endosomal endoribonucleases, RNaseT2 and RNase2, can process RNA for TLR8 recognition. In the endosome, RNase2 and -T2 act synergistically to release uridine from oligoribonucleotides, with RNaseT2 cleaving preferentially before and RNase2 after uridines. Live bacteria, P. falciparum-infected red blood cells, purified pathogen RNA, and synthetic ligands all required RNase processing for TLR8 activation, and uridine supplementation restored RNA recognition in RNASE2−/− or RNASET2−/− but not double knockout cells. Strikingly, peripheral blood mononuclear cells from RNaseT2 hypomorphic patients did not respond to bacterial RNA but did to small-molecule TLR8 agonists. Our data provide a novel insight into TLR8 activation and its differences between cell types and species.
Role of Dual Oxidase 1 in severe malaria
Authors: Sarr Demba , Pathak Ashutosh K. , Murdock Courtney , Rada Balazs 
Published: January 2023

Abstract
Despite important advances in malaria control, the disease is still a major public health issue in sub-Saharan Africa. Recent reports indicate over 400,000 deaths annually. Parasite resistance to known antimalarial drugs delays control and elimination. Dual oxidase 1 (Duox1), a member of the NADPH oxidase enzyme family, generates hydrogen peroxide that is used by its partner enzyme lactoperoxidase to generate antimicrobial hypothiocyanite. Malaria parasites are susceptible to hypothiocyanite in vitro. Duox1 is required for the generation of hypothiocyanite in vivo. We hypothesized that malaria parasites are susceptible to the Duox1-mediated antimicrobial system in vivo. Duox1-deficient and wild-type, Duox1-expressing mice were infected with Plasmodium berghei by either intravenous injection of sporozoites or exposure to infected mosquitos. The results indicate that Duox1-deficient mice either infected with intravenous injection of P. berghei sporozoites (p&lt;0.004) or by exposure to P. berghei-infected mosquito bites (p&lt;0.002), have significantly higher blood parasite density at peak parasitemia compared to wild-type mice. Survival data indicated that Duox1-deficient mice are more susceptible to P. berghei infection than control animals (p&lt;0.03 for intravenous infection, p&lt;0.02 for exposure to mosquito bites). Histopathological analysis of brain tissues revealed a slightly higher number of indices of cerebral pathology including cerebrovascular infected red blood cells and hemozoin accumulation, hemostasis, and hemorrhage. Overall, these data propose a novel role of Duox1 in delaying the onset of parasitemia and clinical outcomes in malaria infection.
The transcription factor BACH1 promotes tissue damage and host susceptibility in Mycobacterium tuberculosis infection by reducing expression of Gpx4, a major negative regulator of ferroptosis
Authors: Amaral Eduardo Pinheiro , Namasivayam Sivaranjani , Costa Diego L. , Fisher Logan , Bomfim Caio Cesar B. , Andrade Bruno B. , Sher Alan 
Published: January 2023

Abstract
Ferroptosis is a type of regulated necrotic cell death induced by the acumulation of free iron and lipid peroxides. We have previously described a role for ferroptosis in Mtb-induced macrophage necrosis based on its biochemical requirements and its blockade both in vitro and in vivo by a lipid peroxidation inhibitor (fer-1). To help validate these findings and further delineate the mechanism involved we have analyzed Mtb-induced cellular necrosis and host resistance in mice deficient in or overexpressing glutathione peroxidase (Gpx4), an essential regulator of ferroptosis. To do so we generated conditional-knockout mice for Gpx4 by using creERT2, CD45cre and LysMcre systems targeting different cell compartments. After aerosol low dose Mtb infection these conditional-knockout mice showed both increased lung necrosis and elevated pulmonary and splenic bacterial burdens. In the opposite direction, Gpx4-overexpressing mice infected at high dose with Mtb were found to display decreased bacterial burdens as well as reduced pulmonary necrosis. Genetic deletion of BACH1, a transcription factor known to repress antioxidant genes including Gpx4, increased the levels of intracellular glutathione as well as enhanced expression of Gpx4 during Mtb infection in vitro and in vivo. Moreover, Bach1−/− mice infected at high dose with Mtb displayed a significant reduction in bacterial loads and lung necrosis along with lowered levels of lipid peroxides as well as enhanced survival. Together, these findings provide genetic evidence further delineating the role of ferroptosis as a mechanism of host cell death and tissue necrosis in Mtb infection and implicate both Gpx4 and Bach1 as potential targets for host-direct therapy of tuberculosis.
Dual RNA-seq as an effective tool to simultaneously identify transcriptional changes in host macrophages and invading intracellular pathogens
Authors: Choudhury Sreetama , Akhade Ajay Suresh , Subramanian Naeha 
Published: January 2023

Abstract
Intracellular pathogens have evolved strategies to subvert the host immune response and establish infection leading to disease. For example, Mycobacterium tuberculosis (MTB) has been recently reported to effectively counteract immunological and anti-tubercular challenges by activating resistance mechanisms that enable the pathogen to attain an immune tolerant state. A systems scale approach using dual RNA Sequencing revealed key transcriptional factors that enabled researchers to discover a drug combination that delivers more effective killing of MTB. On the basis of our preliminary findings we hypothesize that similar to MTB, Salmonella spp. have evolved to escape host macrophage responses by down-regulating the expression of flagellin, a potent activator of the NLRC4 inflammasome, by taking advantage of a natural host negative feedback mechanism that allows the pathogen to reside intracellularly within macrophages. However, how Salmonella and host transcriptional networks rewire over the course of infection to permit development of an immune-evasive phenotype in the pathogen remains unknown. Using dual RNA-Seq and regulatory network analysis, we propose to simultaneously identify the molecular changes that occur in both the host and the pathogen during infection. We aim to conduct a temporal study to find transcriptional changes at different time points post infection that lead to development of a permissive host environment and allow Salmonella to undergo immune escape within macrophages. Our study will help identify the key regulators that shape host-pathogen crosstalk over the course of Salmonella infection with potentially important implications for bacterial pathogenesis and immunity.
Gasdermin D Promotes AIM2 Inflammasome Activation and Is Required for Host Protection against Francisella novicida
Authors: zheng Min , Zhu Qi Fan , Balakrishnan Arjun , Karki Rajendra , Kanneganti Thirumala-Devi 
Published: January 2023

Abstract
The DNA sensor absent in melanoma 2 (AIM2) forms an inflammasome complex with ASC and caspase-1 in response to Francisella tularensis subspecies novicida infection, leading to maturation of IL-1b and IL-18 and pyroptosis. AIM2 is critical for host protection against F. novicida infection in vivo; however, the role of pyroptosis downstream of the AIM2 inflammasome is unknown. Recent studies have identified gasdermin D (GSDMD) as the molecule executing pyroptosis by forming pores on the plasma membrane following activation by inflammatory caspase-1 and -11. In this study, we report that GSDMD-deficient mice were susceptible to F. novicida infection compared with wild type mice. Interestingly, we observed that GSDMD is required for optimal caspase-1 activation and pyroptotic cell death in F. novicida–infected bone marrow–derived macrophages. Furthermore, caspase-1 activation was compromised in bone marrow–derived macrophages lacking GSDMD stimulated with other AIM2 inflammasome triggers, including poly(dA:dT) transfection and mouse CMV infection. Overall, our study highlights a function, to our knowledge previously unknown, for GSDMD in promoting caspase-1 activation by AIM2 inflammasome.
Runx1 is a key regulator of T cell anergy
Authors: Wilfahrt Drew Nicholas , Hsu Fan Chi , McCue Shaylene , Rajcula Matthew , Shapiro Virginia Smith 
Published: January 2023

Abstract
T cell anergy is a state of cellular hyporesponsiveness that prevents the propagation of an immune response to self. Consequently, the development and maintenance of the anergy program in T cells is tightly controlled. We found in wild type (WT) mice that anergic T cells, defined by co-expression of the cell surface markers CD73 and FR4, express lower expression of the transcription factor Runx1. To test if Runx1 acts as a negative regulator of the anergy program, we utilized a 1:1 mixed bone marrow chimera (BMC) system with ER-Cre Runx1 cKO and WT B6.SJL bone marrow to delete Runx1 in mature CD4+ T cells. Upon tamoxifen treatment and deletion of Runx1, ER-Cre Runx1 cKO CD4+ T cells develop a CD73+FR4+ anergic phenotype. This effect is cell-intrinsic since WT T cells from the same bone marrow chimera do not exhibit the anergic phenotype. Functionally, ER-Cre Runx1 cKO T cells fail to proliferate and produce less IL-2 after TCR/CD28 stimulation, consistent with anergy. Interestingly, WT B6.SJL T cells from the ER-Cre Runx1 cKO:B6.SJL BMC mice fail to proliferate in response to TCR/CD28 stimulation, suggesting Runx1 additionally regulates a cell-extrinsic suppressive mechanism. Using depletion experiments, we found this extrinsic suppression requires FR4+ anergic T cells, but not CD25+ Tregs. Interestingly, the loss of Runx1 leads to the generation of CD73+FR4+ anergy in OT-II T cells, which do not engage their TCR. Thus, the loss of Runx1 drives anergy in the absence of TCR signaling. We conducted RNA-sequencing on ER-Cre Runx1 cKO and WT anergic T cells, and have identified several genes regulated by Runx1 that could play a role in anergy. Further analysis will serve to define the molecular mechanisms Runx1 employs to regulate T cell anergy.
The role of ERK2 in dendritic cell function
Authors: Abdul-Baki Nawal Samer , Jeffreys Sean , Negron Austin Joseph , Forsthuber Thomas G 
Published: January 2023

Abstract
Dendritic cells (DCs) are an important link between the innate and adaptive immune systems, specifically by serving as key regulators of T cell-dependent (TD) immune responses. In DCs, several processes critical for initiating TD immune responses, such as migration, provision of costimulatory signals, and antigen uptake and presentation, utilize the mitogen-activated protein kinase (MAPK) signaling pathway. The dysregulation of these processes can result in the aberrant activation of autoreactive CD4+ T cells, resulting in autoimmune disease. Extracellular signal-regulated kinase 1 and 2 (ERK1/2) are key effectors of the MAPK pathway, and while ERK1 has been shown to be a critical regulator of DC migration and TLR-induced IL-10 secretion, the function of ERK2 remains unknown. Our lab has developed a novel mouse model in which the inducible Cre-mediated deletion of Erk2 is accompanied by the expression of an eYFP reporter protein. This provides us the unique ability to circumvent the embryonic lethality of deleting Erk2 in the germline while also allowing the detection of viable Erk2-deficient cells via flow cytometry. Preliminary data using this model has shown that Erk2Δ bone marrow-derived DCs (BMDCs), as well as Erk2Δ splenic DCs, exhibit altered expression of surface markers associated with T cell costimulation, antigen presentation, and migration compared with DCs from littermate controls. Taken together, this suggests that ERK2 plays a unique role in the regulation of several DC functions, potentially opening a new approach to treating CD4+ T cell-mediated autoimmune diseases.
Dissecting the molecular mechanisms underpinning T cell help for Dendritic Cell
Authors: Gressier Elise Marie , Whitney Paul , Schmidt Susanne , Bedoui Sammy 
Published: January 2023

Abstract
CD8+ T cell priming relies on the ability of dendritic cells (DCs) to present antigen as well as to communicate contextual cues associated with antigen acquisition. Efficient CD8+ T cell response often requires DC interactions with helper CD4+ T cells through CD40-CD40L binding. Previously, our work showed that CD4+ T cell help amplifies the capacity of DCs to generate efficient priming of CD8+ T cell in response to suboptimal innate stimuli. Focusing on the CD40-driven amplification of innate pathways induced in IFN-α/β-stimulated DCs, this study explores the dynamics and molecular mechanisms underpinning such help phenotype. We have observed that the CD40-mediated amplification of IFN-α responses follows precise kinetics and affects only a portion of the innate stimulus-induced genes such as Il-15, Ccl5 or Tnf-α. Interestingly, a group of genes, unresponsive to IFN-α alone, required the combination of both stimuli to trigger their expression. These results highlighted the induction of two distinct patterns of gene regulation in response to CD40 and IFN-α stimulations, the amplified and the combinatorial. Based on transcriptomics, proteomics and phosphoproteomics data sets analyses, our data mining suggests the cooperation between IRFs and NF-κB transcription factors, acting in synergy towards the enhancement of DC responses and governing which genes can be amplified. Furthermore, the gene regulation and post-transcriptional modification of proteins involved in the regulation of NF-κB indicate a tight control of this signaling pathway. By dissecting how T cell help amplifies innate signals required for CD8+ T cell priming, this work will assist in the development of more targeted T-cell-based therapeutic strategies.
PRMT5 controls pathogenicity and metabolic genes during Th17 polarization
Authors: Piedra-Quintero Zayda L. , Sengupta Shouvonik , Webb Lindsay M , Amici Stephanie A , Laliotis Georgios , Tsichlis Philip N , Guerau-de-Arellano Mireia 
Published: January 2023

Abstract
PRMT5 catalyzes symmetric dimethylation (SDM) on arginine residues. PRMT5 methylates histone H3 and H4 producing remodeling of chromatin and regulation of gene transcription. PRMT5 is induced after T cell activation. Furthermore, both PRMT5 inhibitors and PRMT5 knockdown impair T cell proliferation and activation. However, the role of PRMT5 in T cell differentiation has not been analyzed. T cells undergo metabolic reprograming during activation which is critical for polarization. Differentiating T cells increase bioenergetics and anabolic pathways enhancing glycolysis, catabolism, uptake of fatty acids and oxidative phosphorylation. Whether PRMT5 has an impact on Th17 differentiation and metabolic reprograming is unknown. To address this question, we performed Th17 differentiation and RNA sequencing analyses in T cells from PRMT5fl/fl and iCD4-PRMT5Δ/Δ mice. Th17 differentiation was sharply suppressed in PRMT5 KO T cells, in which 25–30% of genes in the glycolysis, lactate or TCA pathways were reduced. To evaluate the functional effects of PRMT5 on energy metabolism, extracellular acidification rate (ECAR) and Oxygen consumption rate (OCR) were analyzed in Jurkat T cells transduced with control or PRMT5 shRNA and lactate secretion was measured on supernatants of Th1 and Th17 cells from PRMT5fl/fl and iCD4-PRMT5Δ/Δ mice. Knock down of PRMT5 decreased ECAR in Jurkat cells and lactate production in Th1 and Th17 cells in absence of PRMT5. In conclusion, PRMT5 promotes glycolytic energy metabolism and Th17 differentiation in T cells.
Dynamic changes in patterns of ganglioside expression characterize maturation of lymphoid lineage cells into effector cells and suggest a close relationship between CD8+ T cells and NK cells
Authors: Johnson Taylor , Knapp Mary-Peyton A. , Ritter Madison K. , King-Lyons Natalie D. , Grier Jennifer T. , Rainer Robert O , Connell Terry D. , Arce Sergio 
Published: January 2023

Abstract
Gangliosides are glycosphingolipids that play important regulatory roles in cell signaling and differentiation. To investigate their expression patterns during lymphoid cell development, human PBMC were stained with recombinant B subunits of LT-IIa, LT-IIb, or LT-IIc and with select mAb. FACS analysis showed that ganglioside ligands for LT-IIaB, LT-IIbB, and LT-IIcB were increasingly expressed during transition from naïve to memory to effector memory CD4+ T cells, with ganglioside ligands for LT-IIbB exhibiting the greatest increase. A similar trend was observed in CD8+ T cell subsets, except no major changes in the expression of LT-IIaB ligands were detected. Patterns of ganglioside expression in NK cell subsets were remarkably similar to those observed in the CD8+ T cells: The ganglioside ligands for LT-IIbB and LT-IIcB were increasingly expressed during transition from tissue-resident to effector to differentiated/exhausted NK cells, with ganglioside ligands for LT-IIbB exhibiting the greatest increase and ligands for LT-IIaB showing little change across subsets. Finally, expression of LT-IIaB- and LT-IIcB-binding gangliosides increased during transition from naïve to memory to antibody-secreting B cells, with ganglioside ligands for LT-IIaB exhibiting the greatest increase and ligands for LT-IIbB showing little change across subsets. Our results demonstrated the existence of dynamic changes in the patterns of gangliosides expressed throughout lymphoid cell development and differentiation. The distinct patterns suggest the existence of cell signaling differences between and within the distinct lymphoid cell lineages and a close developmental and functional relationship between CD8+ T cells and NK cells.
Substrate rigidity affects human regulatory T cell induction in vitro
Authors: Shi Lingting , Kam Lance 
Published: January 2023

Abstract
Immunotherapy using regulatory T cells (Tregs) has shown recent successes in the treatment of autoimmune diseases. While natural Tregs are unstable and dysfunctional in the inflammatory milieu, induced Tregs are more potent and durable. Tregs can be induced from CD4+CD25− T cells in vitro with TGF-β and IL-2 during activation. Chemical pathways in Treg induction have been heavily investigated, but the impact of mechanical cues has not been thoroughly explored. As T cell activation has been shown to be sensitive to the substrate rigidity, Treg induction may also be mechanosensitive. To test this hypothesis, Tregs were induced on polyacrylamide gels of different rigidities (Young’s modulus of 5 to 110 kPa) coated with anti-CD3 and anti-CD28 for 72 hrs. The stiffer substrate significantly increased Treg induction, measured by percent FoxP3 high T cells. To further understand this process, single cell RNA-Seq analysis was performed on cells induced on 5 and 110 kPa gels, which revealed three clusters including conventional CD4+ cells, transition cells, and Tregs. For 5 kPa substrates, a higher proportion of cells expressed the FOXP3 genes than detected protein, whereas the proportions of cells that express the FOXP3 gene and protein were consistent on the 110 kPa gels. FOXP3+ cells on the softer gel also showed upregulation of genes that encode for ribosomal proteins and proteasomes. Thus, there could be some mechanism inhibiting expression or promoting degradation of FoxP3 protein in 5 kPa. Lastly, the induced Tregs in two groups exhibited different cell cycle profiles. These results indicated the mechanosensitive nature of Treg induction, which can assist in the biomaterial design for generating Tregs to advance Treg adoptive therapy.
SUMO-specific protease 2 restrains the differentiation of Th17 cells
Authors: Yang Tsan-Tzu , Shih Hsiu-Ming , Lin Kuo-I 
Published: January 2023

Abstract
Accumulating evidence suggests that posttranslational modifications (PTMs) play a critical role in the regulation of cellular functions and disease progression. Several reports indicated that SUMOylation, a type of PTMs, contributes to diseases through modulation of cell signaling and functions. The process of SUMOylation is dynamic and can be reversibly removed by the sentrin-specific protease (SENP) family. Smad4 has been shown to suppress the differentiation of pathogenic Th17 cells and can be deSUMOylated by SENP2. Here, we would like to study whether SUMOylation may affect T cell development and differentiation, and T cell-mediated diseases.
To study the roles of Senp2 in T cell lineage, we generated Senp2f/f×Lck-cre (CKO) mice. We found that there were more Th1 and Th17 cells in CKO mice in the steady state, as compared with those in littermate controls (wild type, WT) mice. Besides, Senp2-deficiency in T cells also promotes the progression of dextran sodium sulfate (DSS)-induced colitis in mice. The levels of IFNg and IL-17 produced by in vitro differentiated Th1 and Th17 cells, respectively, were higher when Senp2 is deleted. The enzymatic activity of Senp2 is required for the inhibition of Th17 differentiation; as compared with the effects of lentiviral vector expressing wild type Senp2, transduction of differentiating CKO Th17 cells with a lentiviral vector expressing a catalytic domain mutant Senp2 failed to suppress the frequency of Th17 cells. We are examining if SUMOylation affects the function of Smad4 in Th17 cells. Results from this study may provide insights into the new therapeutic strategy for the control of Th17-mediated diseases.