We have developed a suite of tools for integrated analysis of T-Cell-Receptor Sequencing data to define and track alloreactive T-cells in human transplant studies. This has enabled discovery of ...sequences and patterns of T-cell enrichment and deletion associated with clinical outcomes such as transplant rejection and tolerance. The codebase includes user-friendly default analyses with customizable parameters which greatly accelerate computational workflows and provide robust statistics comparing post-transplant specimens to pre-transplant baseline. It also includes helper functions for robust characterization of T-cell-repertoire diversity, sample-to-sample divergence, resolution of sample-of-origin ambiguity in pooled assays, and functions to output all sequences defined as alloreactive.
•We develop a tool to define and track alloreactive T-cells after transplantation.•This enables study of transplant rejection and graft-versus-host disease.•The codebase includes user-friendly default analyses with customizable parameters.•It also includes functions to characterize repertoire diversity and divergence.•We believe our method will be of interest to the readership of Software Impacts.
Alloreactive donor T cells are the driving force in the induction of graft-versus-host disease (GVHD), yet little is known about T cell metabolism in response to alloantigens after hematopoietic cell ...transplantation (HCT). Here, we have demonstrated that donor T cells undergo metabolic reprograming after allogeneic HCT. Specifically, we employed a murine allogeneic BM transplant model and determined that T cells switch from fatty acid β-oxidation (FAO) and pyruvate oxidation via the tricarboxylic (TCA) cycle to aerobic glycolysis, thereby increasing dependence upon glutaminolysis and the pentose phosphate pathway. Glycolysis was required for optimal function of alloantigen-activated T cells and induction of GVHD, as inhibition of glycolysis by targeting mTORC1 or 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) ameliorated GVHD mortality and morbidity. Together, our results indicate that donor T cells use glycolysis as the predominant metabolic process after allogeneic HCT and suggest that glycolysis has potential as a therapeutic target for the control of GVHD.
Mammalian thioredoxin reductase 1 (TrxR1) is considered to be an important anticancer drug target and to be involved in both carcinogenesis and cancer progression. Here, we report that ethaselen, a ...novel organoselenium compound with anticancer activity, specifically binds to the unique selenocysteine–cysteine redox pair in the C-terminal active site of mammalian TrxR1. Ethaselen was found to be a potent inhibitor rather than an efficient substrate of mammalian TrxR1. It effectively inhibits wild-type mammalian TrxR1 at submicromolar concentrations with an initial mixed-type inhibition pattern. By using recombinant human TrxR1 variants and human glutathione reductase, we prove that ethaselen specifically targets the C-terminal but not the N-terminal active site of mammalian TrxR1. In A549 human lung cancer cells, ethaselen significantly suppresses cell viability in parallel with direct inhibition of TrxR1 activity. It does not, however, alter either the disulfide-reduction capability of thioredoxin or the activity of glutathione reductase. As a downstream effect of TrxR1 inactivation, ethaselen causes a dose-dependent thioredoxin oxidation and enhances the levels of cellular reactive oxygen species in A549 cells. Thus, we propose ethaselen as the first selenium-containing inhibitor of mammalian TrxR1 and provide evidence that selenium compounds can act as anticancer agents based on mammalian TrxR1 inhibition.
► A novel organoselenium anticancer agent, ethaselen, is characterized as an inhibitor of wild-type mammalian TrxR1. ► At nanomolar concentrations ethaselen specifically targets the Sec-containing C-terminal active site in TrxR1. ► Treatment of cancer cells with ethaselen reduced cell viability in parallel with intracellular TrxR1 inhibition. ► Ethaselen is the first selenium-containing anticancer agent identified as a specific mammalian TrxR1 inhibitor. ► Ethaselen can serve as a template for future drug design approaches.
Enterovirus (EV), a genus within the Picornaviridae family, contains icosahedral positivestranded RNA viruses linked to different human and mammalian diseases with a variety of symptoms ranging from ...the common cold to central nervous system infection. An important member within this genus is EV-D68. Unlike many enteroviruses that use the gastrointestinal tract as the transmission and propagation route, EV-D68 infects the respiratory tract and causes respiratory illness, especially in children. Severe infections of EV-D68 also lead to acute flaccid myelitis (AFM), a polio-like neurological disease. Especially in recent years, EV-D68 has been on a global upswing. However, no antiviral interventions against EV-D68 infection have been developed to date. Antibodies neutralizing EV-D68 have significant vaccine and therapeutic potentials. Here, the structures of the immune complex between EV-D68 and the Fab molecules of EV-D68 human monoclonal antibodies have been reconstructed using cryo-electron microscopy (cryo-EM). These structures show two Fab binding loci on the virion surface as well as the essential amino acids involved in binding. In addition to antibodies, a drug candidate against EVD68 has been investigated in this work as an antiviral strategy. It is likely that this drug blocks viral entry through binding in the hydrophobic pocket underneath the viral protein 1, the largest structural protein of EV-D68. Furthermore, the morphogenesis of EV-D94, another causative virus of polio-like disease, which is closely related to EV-D68 with 85% sequence identity, has been investigated using cryo-EM. Compared to EV-D68, the shape of the canyon and the loops containing the immunogenic recognition sites are different in EV-D94. The structures of each of the three stages of EV-D94 particles (the full native virion, the uncoating intermediate, and the empty virion) were identified and delineate the viral uncoating process. These findings reveal useful knowledge and new insights to develop treatments against human EVs.
MicroRNAs (miRs) play important roles in orchestrating many aspects of the immune response. The miR-17-92 cluster, which encodes 6 miRs including 17, 18a, 19a, 20a, 19b-1, and 92-1, is among the best ...characterized of these miRs. The miR-17-92 cluster has been shown to regulate a variety of immune responses including infection, tumor, and autoimmunity, but the role of this cluster in T-cell response to alloantigens has not been previously explored. By using major histocompatibility complex (MHC)-matched, -mismatched, and haploidentical murine models of allogeneic bone marrow transplantation (allo-BMT), we demonstrate that the expression of miR-17-92 on donor T cells is essential for the induction of graft-versus-host disease (GVHD), but dispensable for the graft-versus-leukemia (GVL) effect. The miR-17-92 plays a major role in promoting CD4 T-cell activation, proliferation, survival, and Th1 differentiation, while inhibiting Th2 and iTreg differentiation. Alternatively, miR-17-92 may promote migration of CD8 T cells to GVHD target organs, but has minimal impact on CD8 T-cell proliferation, survival, or cytolytic function, which could contribute to the preserved GVL effect mediated by T cells deficient for miR-17-92. Furthermore, we evaluated a translational approach and found that systemic administration of antagomir to block miR-17 or miR-19b in this cluster significantly inhibited alloreactive T-cell expansion and interferon-γ (IFNγ) production, and prolonged the survival in recipients afflicted with GVHD while preserving the GVL effect. Taken together, the current work provides a strong rationale and demonstrates the feasibility to target miR-17-92 for the control of GVHD while preserving GVL activity after allo-BMT.
•miR-17-92 is required for T cells to mediate GVHD but not the GVL effect.•Targeting miR-17-92 with antagomirs efficiently alleviates GVHD.
Human intestinal transplantation often results in long-term mixed chimerism of donor and recipient blood in transplant patients. We followed the phenotypes of chimeric peripheral blood cells in 21 ...patients receiving intestinal allografts over 5 years. Donor lymphocyte phenotypes suggested a contribution of hematopoietic stem and progenitor cells (HSPCs) from the graft. Surprisingly, we detected donor-derived HSPCs in intestinal mucosa, Peyer’s patches, mesenteric lymph nodes, and liver. Human gut HSPCs are phenotypically similar to bone marrow HSPCs and have multilineage differentiation potential in vitro and in vivo. Analysis of circulating post-transplant donor T cells suggests that they undergo selection in recipient lymphoid organs to acquire immune tolerance. Our longitudinal study of human HSPCs carried in intestinal allografts demonstrates their turnover kinetics and gradual replacement of donor-derived HSPCs from a circulating pool. Thus, we have demonstrated the existence of functioning HSPCs in human intestines with implications for promoting tolerance in transplant recipients.
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•Human intestine contains hematopoietic stem cells and multiple types of progenitors•Donor graft HSPCs contribute to multilineage blood chimerism in the recipient•Long-term circulating donor T cells are tolerant to the recipient but functional•Intestinal HSPCs undergo replacement by the recipient from a circulating pool
Fu et al. demonstrate the presence and multilineage differentiation potential of hematopoietic stem and progenitor cells (HSPCs) carried in human intestinal allografts. These contribute to peripheral blood mixed chimerism in the recipient. Kinetic turnover studies revealed the gradual replacement of intestinal mucosal HSPCs by a circulating pool in humans.
Diabetes accelerates vascular senescence, which is the basis for atherosclerosis and stiffness. The activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and ...oxidative stress are closely associated with progressive senescence in vascular smooth muscle cells (VSMCs). The vascular protective effect of FGF21 has gradually gained increasing attention, but its role in diabetes-induced vascular senescence needs further investigation. In this study, diabetic mice and primary VSMCs are transfected with an FGF21 activation plasmid and treated with a peroxisome proliferator-activated receptor γ (PPARγ) agonist (rosiglitazone), an NLRP3 inhibitor (MCC950), and a spleen tyrosine kinase (SYK)-specific inhibitor, R406, to detect senescence-associated markers. We find that FGF21 overexpression significantly restores the level of catalase (CAT), vascular relaxation, inhibits the intensity of ROSgreen fluorescence and p21 immunofluorescence, and reduces the area of SA-β-gal staining and collagen deposition in the aortas of diabetic mice. FGF21 overexpression restores CAT, inhibits the expression of p21, and limits the area of SA-β-gal staining in VSMCs under high glucose conditions. Mechanistically, FGF21 inhibits SYK phosphorylation, the production of the NLRP3 dimer, the expression of NLRP3, and the colocalization of NLRP3 with PYCARD (ASC), as well as NLRP3 with caspase-1, to reverse the cleavage of PPARγ, preserve CAT levels, suppress ROSgreen density, and reduce the expression of p21 in VSMCs under high glucose conditions. Our results suggest that FGF21 alleviates vascular senescence by regulating the SYK-NLRP3 inflammasome-PPARγ-catalase pathway in diabetic mice.
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