bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chronic chikungunya virus infection disrupts the architecture and function of draining lymphoid tissue
Authors: McCarthy Mary K , Hawman David W , Elmore Susan A , Morrison Thomas E 
Published: January 2023

Abstract
Chikungunya virus (CHIKV) causes large outbreaks of rheumatologic disease, resulting in chronic disease symptoms in up to two-thirds of infected individuals. Studies in humans and animal models suggest that CHIKV infection persists in musculoskeletal tissues, although the mechanisms are unclear. The pathogenic clinical isolate AF15561 persists in joint tissue of WT mice, while the attenuated strain 181/25 is cleared. In contrast, 181/25 persists in joint tissue of Rag1−/− mice at levels similar to AF15561, suggesting that adaptive immune responses are critical for clearance of 181/25 but are impaired during AF15561 infection. We hypothesized that early events in lymphoid tissue during persistent or acute CHIKV infection are distinct and these differences contribute to CHIKV persistence or clearance in joint tissue. To test this hypothesis, we performed functional and histological analyses of the draining lymph node (dLN) during acute and persistent CHIKV infection. In mice infected with 181/25, we detected activation of CD21+CD23+ conventional follicular B cells and increased numbers of Tfh cells. In contrast, activated B cells in the dLN of AF15561-infected mice were CD21lo/−CD23−and Tfh cell numbers were reduced. Acute 181/25 infection also resulted in increased cortex area, plasma cells, and germinal center (GC) formation in the dLN, while the dLN of AF15561-infected mice was depleted of lymphocytes and became fibrotic. Following NP-OVA immunization, development of NP-specific GC B cells was decreased during AF15561, but not 181/25 infection, suggesting that persistent CHIKV infection impairs dLN function. These data provide new insight into the immunologic mechanisms that facilitate CHIKV persistence in joint tissue.
An imbalance between MMPs and TIMPs plays a critical role in the pathogenesis of HIV-associated neurocognitive disorders
Authors: Xing Yanyan , Shepherd Nicole , Lan Jie , Yang Kai , Amet Tohti , Dong Jun , Yu Qigui 
Published: January 2023

Abstract
HIV-associated neurocognitive disorders (HAND) affects approximately 50% of HIV-infected individuals, and disruption of the blood brain barrier (BBB) has been observed in individuals with HAND. One of the underlying mechanisms of BBB breakdown is an imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs), which has not been fully explored in HAND. In our present study, we used ELISA and zymography assays to examine the protein levels and enzyme activities of MMPs and/or TIMPs in plasma from a total of 59 HIV-positive individuals and 16 uninfected controls. We found that the concentration and enzyme activity of MMP-2 and MMP-9, two of the most important members of the MMP family, were increased in the plasma of HIV patients compared to HIV-negative controls. Plasma levels of TIMP-1 and TIMP-4 were not affected, while TIMP-3 was significantly increased in HIV patients. Strikingly, TIMP-2 was significantly down-regulated in HIV-1 patients. We also showed that neural cells, especially astrocytes, were able to release both MMPs and TIMPs, and such secretion was regulated by inflammatory factors like IL-1β or growth factors like TGF-β1. Furthermore, we found that TIMP-2 played a dual role on proMMP-2 activation via the ternary complex of MT1-MMP/TIMP-2/proMMP-2 on the surface of astrocytes, as low concentrations of TIMP-2 activated proMMP-2 and high concentrations inhibited proMMP-2 activity. In summary, our results demonstrate that decreased TIMP-2 found in HIV patients enhances MMP-2 activity, which is associated with BBB breakdown in HIV patients. Exogenous administration of TIMP-2 to maintain MMPs/TIMP-2 homeostasis may represent a potential therapy for HAND.
Liver-associated macrophage infiltration and altered cellular signaling in SIV-infected macaques.
Authors: Fisher Bridget , Arang Nadia , Klatt Nichole R , Kaushansky Alexis , Sodora Donald 
Published: January 2023

Abstract
Liver disease remains an important contributor to morbidity and mortality in HIV-infected patients. In addition to the effects of HIV replication, bacterial translocation from the gastrointestinal tract potentially contributes to liver dysfunction. Indeed, bacteria leaving the gut filter through the liver via portal vein circulation. Providing patients with combination anti-retroviral therapy (cART) does provide some reduction to the generalized immune inflammation, but also can induce liver toxicity. The SIV macaque model recapitulates HIV immune activation and bacterial translocation and was utilized here to evaluate livers of uninfected (n=3), SIV-infected (n=5), and SIV-infected/cART-treated rhesus macaques (n=6). Using immunofluorescence microscopy, CD68+ macrophages (associated with inflammation) were demonstrated to increase in livers of SIV+ macaques, but normalize in cART-treated SIV+ macaques. In addition, reverse-phase protein arrays (RPPA) identified a number of signaling proteins that were activated (phosphorylated) in SIV+ macaques, including proteins involved in the Wnt/beta-catenin pathway (e.g. Dvl-3, pGSK3αβ) as well as inflammatory STAT (e.g. pSTAT2) and NFkB signaling proteins. Assessment of SIV+/cART-treated macaques determined that the elevation in these same signaling pathways could be observed even after 7–8 months of cART. Collectively, this suggests that although cART treatment can reverse macrophage infiltration in the liver during SIV infection, it does not restore normal hepatocyte cellular signaling networks. We conclude that SIV infection results in liver immune activation and that residual liver inflammation persists following cART administration.
Evasion of the African green monkey protein kinase R pathway by mutation of vaccinia virus RNA polymerase
Authors: Brennan Greg , Kitzman Jacob O. , Shendure Jay , Geballe Adam P. 
Published: January 2023

Abstract
One of the earliest barriers to cross-species transmission is mediated by host restriction factors, a group of antiviral proteins that have evolved to detect and then inhibit viral replication. To productively infect a new species, viruses must rapidly adapt to overcome host-specific orthologs of these restriction factors. To model this process we created a recombinant vaccinia virus (VACV), replacing its antagonists of the host restriction factor PKR with the rhesus cytomegalovirus PKR antagonist RhTRS1 (VACVΔEΔK+RhTRS1). Relative to wildtype virus, VACVΔEΔK+RhTRS1 replication was reduced 100-fold in primary African green monkey (AGM) fibroblasts. This replication defect was mediated entirely by PKR. After several rounds of serial passage, we found that genetic amplification of rhtrs1 rescued VACVΔEΔK+RhTRS1 replication in AGM cells. Further serial passage identified mutations in two VACV genes that were individually sufficient to rescue VACVΔEΔK+RhTRS1 replication in AGM cells. Fixation of these mutations coincided with collapse of the rhtrs1 amplification. One of these mutations occurred in the catalytic subunit of the viral RNA polymerase, A24R, and provided a replication benefit independent of rhtrs1. Different mutations in A24R have been shown to prevent activation of RNase L by reducing dsRNA production during viral infection. However, the A24R mutation that evolved during this serial passage does not prevent RNase L activation in AGM cells. Furthermore, this mutation does not decrease the total concentration of dsRNA produced during infection. This work identifies new PKR evasion genes, and suggests that the viral RNA polymerase is an important modulator of multiple host innate immune responses during infection.
HTLV-1 infection and neuropathogenesis in the context of Rag1−/−γc−/− (RAG1) and BLT mice
Authors: Jain Pooja , Ginwala Rashida , Charlins Paige , Akkina Ramesh , Loonawat Ronak , Caruso3 Breanna , Jacobson Steven , Sreedhar Sreesha , Khan Zafar 
Published: January 2023

Abstract
HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a disabling chronic inflammatory disease of the central nervous system (CNS) with similarities to multiple sclerosis (MS). To date, the lack of a suitable small animal model has hindered our quest to understand the immuno- and neuropathogenesis of HTLV-1 in an in vivo system. Previous work from others have established that host immune response plays a critical role in the outcome of HTLV-1 infection, which could be better tested in the context of humanized (hu) mice. Thus, we employ here the Rag1 as well as Bone marrow-Liver-Thymic (BLT) mouse models for engraftment of human CD34+ hematopoietic stem cells and followed HTLV-1 infection. Flow cytometry and histological analyses revealed reconstitution of Rag1 and BLT mice with human immune cells, including macrophages, dendritic cells, T cells and B cells. Proviral load (PVL) was determined in the peripheral blood, spleen, and other organs of neonatal and adult Rag1 and BLT hu-mice by droplet digital PCR. Tax showed peak expression at 14 wpi in Rag1 mice with continued expression until 16 weeks. Within blood, PVL and viral protein Tax was detected as early as 2 wks post-infection (wpi) in Rag-1 and BLT hu-mice. Successful infection was followed by immune activation and Tax expression within lymphoid organs. Moreover, lymphocytic infiltration with concomitant Tax expression and resulting myelin disruption were observed in the spinal cord of the infected mice. These data represents the first attempt to establish HTLV-1 neuropathogenesis in the context of RAG1 and BLT mice suggesting possibility of developing a small animal model of HAM/TSP in humanized mice.
Blockade of proteasomal degradation enhances MHC-II dependent peptide epitope production through chaperone dependent autophagy in dendritic cells infected with Mycobacterium bovis BCG vaccine
Authors: Khan Arshad , Moruno Jose Felix , Tsvetkov Andrey , Jagannath Chinnaswamy 
Published: January 2023

Abstract
Bacillus Calmette Guerin (BCG) is the most frequently used and safe live attenuated vaccine against human tuberculosis. BCG secretes antigen-85B (Ag85B) which is an immunodominant protein generating protective CD4 T cell responses against tuberculosis. We found that over-expression of Ag85B in BCG (85B-BCG) led to aggresome formation in the cytosol of primary mouse dendritic cells. Aggresomes were cleaved through both proteasomes and lysosomes since, blockade of proteasomes using bortezomib led to an increase in the presentation of the p25-epitope of Ag85B to CD4 T cells, which secreted IL-2. We demonstrate here that during the initial stages of aggresome formation, much of the secreted Ag85B is lost through proteasomal degradation while over-expression led to the ubiquitination of Ag85B containing aggresomes. Using siRNA knockdown and biochemical inhibition for protein sorting agents, we demonstrate here that ubiquitinated Ag85B complexes recruit ‘co-chaperone Carboxyl Terminus HSP70/90 Interacting Protein’ (CHIP), which in turn binds to hsp70 triggering a cascade where hsp70 binds to bcl2-associated athanogene-3 (BAG3) followed by p62. The latter culminates in LC3 activation and formation of an autophagosome that delivers the Ag85B-chaperone complex to lysosomes for autophago-lysosomal degradation and p25-epitope presentation to CD4 T cells. Interestingly, blockade of proteasomes led to an increase in CHIP activity of DCs enhancing p25-epitope presentation to CD4 T cells. Thus, intrinsic degradation of subunit vaccines through proteasomes may prevent the efficacy of MHC-II pathway while CHIP dependent autophagy may provide a means to enhance epitopes for CD4 T cells.
Interferon-γ receptor and STAT1 signaling in B cells are central to spontaneous germinal center formation and autoimmunity
Authors: Domeier Phillip P , Chodisetti Sathi Babu , Soni Chetna , Schell Stephanie L , Elias Melinda J , Kitamura Daisuke , Rahman Ziaur 
Published: January 2023

Abstract
In Systemic Lupus Erythematosus (SLE), spontaneously developed germinal centers (Spt-GCs) harbor AutoAb-producing B cells that promote disease, but the mechanisms that control Spt-GC development are not clear. Here we report that B cell-intrinsic IFNγR and STAT1 signaling are essential for Spt-GC formation. The IFNγR deficiency, however, does not significantly affect foreign Ag-induced GC and Tfh responses, suggesting that two distinct mechanisms regulate foreign-Ag vs Spt-GC responses. We also demonstrate that IFNγR-mediated STAT1 signaling drives T-bet expression, pro-GC gene expression and IFNγ production by B cells, which are critical for Spt-GC and Tfh development. To understand how IFNγ signaling regulates the Spt-GC response and associated AutoAb production in SLE, we utilized B6.Sle1b mice that harbor the lupus-prone NZM2410 strain-derived SLAM locus. B6.Sle1b mice exhibit elevated Spt-GC and follicular helper T cell (Tfh) responses that associate with impaired B cell selection in GCs. B6.Sle1b mice with B cell intrinsic IFNγR deficiency have significantly reduced Spt-GC and Tfh responses resulting in a markedly lower number of IgG-producing antibody forming cells and diminished IgG2c and IgG2b autoantibody titers compared to B6.Sle1b mice. Additionally, the proliferation and differentiation of DNA-reactive B cells into a GC B cell phenotype require B cell-intrinsic IFNγR signaling. Together, our data define a novel B cell-intrinsic IFNγR signaling pathway in Spt-GC development and autoimmunity.
Stability of Foxp3 mRNA is controlled by SAMHD1 in human T regulatory cells
Authors: Kim Yong Chan , Kim Kee Kwang , Yoon Jeong Heon , Shevach Ethan M , Scott David W 
Published: January 2023

Abstract
Clinical application of antigen-specific T regulatory cells (Tregs) offers promise for the treatment of undesirable immune diseases. To achieve this goal, long-term expansion of Tregs is required to obtain sufficient numbers of cells. However, human Tregs are not stable ex vivo. Therefore, we previously developed an innovative Treg expansion protocol using phosphorothioated random oligonucleotides (ODNps25). The addition of ODNps25 successfully resulted in the stabilization of engineered antigen-specific Tregs, however, the mechanism is not fully characterized. We first identified SAMHD1 (sterile alpha motif and HD domain 1) as an ODNps25 binding protein using a UV-crosslinking pull-down strategy. SAMHD1 physically interacted with the 3′ untranslated region (UTR) of Foxp3 mRNA and was translocated from nucleus to cytoplasm after ODNps25 treatment. Importantly, addition of ODNps25 enhanced the interaction of SAMHD1 and Foxp3 mRNA significantly, and this interaction was increased by TCR stimulation. Since ODNps25 binds to the nuclease (HD) domain of SAMHD1, we then established that overexpression of a nuclease-deficient mutant (D137N) in Tregs significantly stabilized the expression level of Foxp3 protein. This mutant also enhanced stability of a luciferase reporter, followed by the 3′ UTR of Foxp3 mRNA. Additionally, we also found that phosphorylation of the threonine residue (Thr592), which is a regulatory site to control SAMHD1 activity, was clearly downregulated in Tregs. Taken together, we suggest that ODNs interact with the HD of SAMHD1 to interfere with its nuclease activity, thereby stabilizing 3′ UTR of FoxP3 mRNA in long-term culture.
Enhanced PI3K/AKT/mTOR responses are associated with resistance to activation-induced cell death and expansion of memory CD4+ T cells in T1D subjects and healthy carriers of the PTPN22 risk variant
Authors: Habib Tania J , Turner Michael S , Anderson Warren , Funk Andrew , Rieck Mary , Puri Kamal D , Greenbaum Carla , Long S. Alice , Buckner Jane H. 
Published: January 2023

Abstract
The genetic variant PTPN22 1858T, encoding Lyp620W, confers increased risk for multiple autoimmune diseases including Type 1 diabetes (T1D). To date, Lyp620W has been associated with increased CD4+memory T cells and enhanced Th1 responses in healthy carriers. However, it is not clear whether this is due to altered lineage commitment and/or survival within the CD4+memory T cell compartment. Here, we determined the mechanism by which Lyp620W alters human CD4+memory T cell homeostasis in PTPN22 1858T carriers and T1D subjects. T1D subjects displayed significantly increased CD4+ memory T cells as compared to healthy individuals irrespective of PTPN22 genotype, which was further increased in homozygous carriers of PTPN22 1858T, suggesting a partial role for this variant. Among healthy 1858T carriers, we found a significant increase in the magnitude of Th1 effector responses, but not enhanced Th1 differentiation. Consistent with increased survival, TCR-induced PI3K/AKT/mTOR pathway responses and BCL-2 expression were augmented in CD4+ memory T cells from healthy 1858T carriers. Importantly, these alterations were associated with increased resistance to TCR-mediated apoptosis in CD4+ memory T cells. Similar changes in PI3K/AKT signaling and T cell survival were observed in the Th1 memory compartment of T1D individuals, and selective inhibition of PI3Kδ reversed the survival phenotypes in memory T cells from both healthy 1858T carriers and T1D subjects. Thus, our combined findings reveal a novel immune ‘signature’ associated with Lyp620W and highlight a clinically-relevant T cell intrinsic mechanism that promotes the survival of potentially pathogenic Th1 effector T cells in T1D.
Epigenetic modulation of inflammatory T cell responses
Authors: Webb Lindsay M , Savardekar Himanshu , Jablonski Kyle , Amici Stephanie A , Panfil Amanda , Smith Porsha , Green Patrick , Li Chenglong , Baiocchi Robert A , Guerau-De-Arellano Mireia 
Published: January 2023

Abstract
Pro-inflammatory T helper (Th) 1 and Th17 cell responses drive autoimmune attack of the central nervous system in Multiple Sclerosis (MS), resulting in disability. In contrast, regulatory Th2 and Treg responses are deficient. The reactivation and expansion of inflammatory T cells is linked to increased severity and active MS disease. Thus, therapeutic strategies that modulate this process would be beneficial. Epigenetic modifications such as histone methylation and acetylation provide control over cellular phenotype. The epigenetic modifying enzyme Protein arginine methyltransferase 5 (PRMT5) is the only known enzyme known to catalyze symmetric dimethylation (SDM) on arginine residues of histones. Although PRMT5 has been shown to be up-regulated in several cancers, there is currently no known role for PRMT5 in T cells. We have found that PRMT5 was up-regulated during re-activation of myelin-specific mouse memory T cells and Experimental Autoimmune Encephalomyelitis (EAE), suggesting that PRMT5 may control expansion of pathogenic autoimmune responses. To test this, we developed novel PRMT5-selective inhibitors in collaboration with the Drug Development Institute at OSU. These novel PRMT5 inhibitors preferentially suppressed Th1 over Th2 cell proliferation, an effect that was partially dependent on IL-2 suppression. In addition, we observed similar effects in human memory T cells, suggesting a conserved function of PRMT5 in both human and mouse. Genetic knockdown of PRMT5 with a short hairpin RNA similarly suppressed inflammatory Th1 cell proliferation. Overall, these data support a role for PRMT5 in memory T cell responses and as a promising therapeutic target in autoimmunity.
Mincle activation and the Syk/Card9 signaling axis are central to development of autoimmune disease of the eye
Authors: Lee Ellen , Brown Brieanna , Snow Paige , Vance Emily , Silver Phyllis , Wells Christine , Caspi Rachel R , Rosenzweig Holly L. 
Published: January 2023

Abstract
We recently identified the innate receptor Mincle, a C-type lectin receptor (CLR) that signals through Syk and Card9, as essential in induction of ocular autoimmunity, using experimental autoimmune uveitis (EAU). Now, we further delineate molecular and cellular factors involved in orchestrating this Mincle-dependent mechanism. EAU is typically induced by immunization with interphotoreceptor retinoid-binding protein (IRBP) in CFA and then evaluated by fundus imaging and histology. When the synthetic Mincle agonist TDB (trehalose-6-6′-dibehenate) was used in lieu of CFA, TDB-immunized mice developed uveitis (p&lt;0.05; n=8/group). This effect required Mincle and its downstream signaling adaptor, Card9, as EAU was reduced in the absence of either molecule (p&lt;0.05, n=10–15/group). When Syk, a kinase upstream of Card9, was pharmacologically inhibited by piceatannol (given i.p., q4d, d0–16), TDB-induced EAU was abrogated (p&lt;0.05 vs. control; n=15/group). These results demonstrated that the adjuvant effect of innate signaling through Mincle is necessary and sufficient to support EAU. Studies with bone marrow (BM) chimeras, performed to define the cellular source of Card9 and Mincle-activated responses, showed that Card9 expression was required in hematopoietic, rather than non-hematopoietic cells (p&lt;0.05; n=10/group). Since Card9 is primarily expressed by myeloid cells, Cre-Lox recombination was used to generate conditional KO mice with CD11c+ dendritic cells (DC) lacking Syk. Syk-deficiency in DCs resulted in reduced disease early after EAU induction (p&lt;0.05 vs. control; n=6–10/group). These studies uncover an essential role for Mincle and the Syk/Card9 axis in autoimmune uveitis.
Deficiency of protein tyrosine phosphatase sigma abolishes resistance of BALB/c mice to EAE by modulating dendritic cell function
Authors: Kong Weimin , Ohtake Yosuke , Li Shuxin , Ganea Doina 
Published: January 2023

Abstract
Recent studies reported that protein tyrosine phosphatase sigma (PTPσ) is expressed in plasmacytoid dendritic cells and that PTPσ−/− mice are more susceptible to inflammatory bowel disease. However, the function of PTPσ in autoimmune diseases has not been explored. The present study is the first report on the effects of PTPσ in experimental autoimmune encephalomyelitis (EAE). In contrast to wild type BALB/c mice which are resistant to EAE, PTPσ−/−BALB/c mice developed EAE. Pathohistology studies indicated severe demyelination, axonal loss and increased immune cell infiltration in the spinal cords of PTPσ−/− BALB/c mice. Gene expression analysis of spinal cords showed increased expression of proinflammatory cytokines and chemokines in PTPσ−/− BALB/c mice. Ex vivo experiments showed higher levels of IFNg and IL17 production in splenocytes isolated from PTPσ−/− EAE mice. PTPσ was highly expressed in conventional dendritic cells (cDC) but not in CD4+ T cells. As a result of PTPσ deficiency, cDC exhibited an inflammatory phenotype characterized by enhanced expression of pro-inflammatory cytokines, chemokine receptors and migration capacity, and decreased expression of anti-inflammatory cytokines. Furthermore, adoptive transfer of PTPσ−/− DC induced more severe disease compared to wild type DC. In conclusion, we established that PTPσ is a negative regulator in EAE, and that this is mediated, at least partially, through effects on DC function.