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Even when successfully Induced, Immunological tolerance to solid organs remains vulnerable to Inflammatory Insults, which can trigger rejection. In a mouse model of cardiac allograft tolerance in which infection with Listeria monocytogenes (Lm) precipitates rejection of previously accepted grafts, we showed that recipient [CD4.sup.+] TCR75 cells reactive to a donor MHC class I-derived peptide become hypofunctional if the allograft is accepted for more than 3 weeks. Paradoxically, infection-induced transplant rejection was not associated with transcriptional or functional reinvigoration of TCR75 cells. We hypothesized that there is heterogeneity in the level of dysfunction of different allospecific T cells, depending on duration of their cognate antigen expression. Unlike [CD4.sup.+] TCR75 cells, [CD4.sup.+] TEa cells specific for a peptide derived from donor MHC class II, an alloantigen whose expression declines after transplantation but remains inducible in settings of inflammation, retained function in tolerant mice and expanded during Lm-induced rejection. Repeated injections of alloantigens drove hypofunction in TEa cells and rendered grafts resistant to Lm-dependent rejection. Our results uncover a functional heterogeneity in allospecific T cells of distinct specificities after tolerance induction and reveal a strategy to defunctionalize a greater repertoire of allospecific T cells, thereby mitigating a critical vulnerability of tolerance., Introduction Achieving stable donor-specific transplantation tolerance holds the potential for vastly improving the quality of life for transplant recipients by eliminating the lifelong exposure to drug toxicity, higher risk of [...]

The intricate immunomodulatory mechanism underlying the onset and progression of chronic rhinosinusitis with nasal polyps (CRSwNP) in chronic sinusitis with nasal polyps remains poorly understood, particularly regarding the regulatory role of dendritic cells (DCs). MicroRNA has been identified as a modulator of DC function. Primary cells have a short time in vitro and their biological characteristics have not changed greatly which can better reflect the growth state of cells in the body, so as to obtain data closer to the physiological function in the body. Our research group has been engaged in the culture of human nasal epithelial progenitor cells (hNEPCs) for a long time, and in previous investigations, we observed downregulation of microRNA‐124 (miR‐124) in patients with chronic sinusitis and nasal polyps. Thus, our current study aims to elucidate the regulatory mechanism of DCs in chronic sinusitis with polyps by examining the impact of miR‐124 on DCs in this context. To accomplish this, we took the nasal mucosa of CRSwNP patients and normal nasal mucosa of non‐rhinitis patients for primary culture. We isolated exosomes from these cells for co‐culture experiments with DCs. Flow cytometry analysis was employed to assess the maturation phenotypes (MHC II, CD80 and CD86), cell cycle and apoptosis levels of DCs. Furthermore, enzyme‐linked immunosorbent assay was utilized to measure the levels of pro‐inflammatory cytokines (IL‐10, IL‐12 and IL‐23). The TLR4/NF‐κB signalling pathway in co‐cultured DCs was evaluated using the western blot assay. Through querying the Targetscan website, we predicted Rab27a as a target gene of miR‐124, which was subsequently validated through double luciferase assay, flow cytometry and other experimental approaches. Our findings demonstrate that MiR‐124 modulates the secretion of CRSwNP epithelial exosomes, thereby influencing DC function via its interaction with the target gene Rab27a. These results offer novel insights into potential therapeutic targets for the treatment of CRSwNP. [ABSTRACT FROM AUTHOR]

Solid organ transplantation is the preferred treatment for end-stage organ failure. Although transplant recipients take life-long immunosuppressive drugs, a substantial percentage of them still reject their allografts. Strikingly, barrier organs colonized with microbiota have significantly shorter half-lives than non-barrier transplanted organs, even in immunosuppressed hosts. We previously demonstrated that skin allografts monocolonized with the common human commensal Staphylococcus epidermidis (S.epi) are rejected faster than germ-free (GF) allografts in mice because the presence of S.epi augments the effector alloimmune response locally in the graft. Here, we tested whether host immune responses against graft-resident commensal microbes, including S.epi, can damage colonized grafts independently from the alloresponse. Naive hosts mounted an anticommensal T cell response to colonized, but not GF, syngeneic skin grafts. Whereas naive antigraft commensal T cells modestly damaged colonized syngeneic skin grafts, hosts with prior anticommensal T cell memory mounted a post-transplant immune response against graft-resident commensals that significantly damaged colonized, syngeneic skin grafts. Importantly, allograft recipients harboring this host-versus-commensal immune response resisted immunosuppression. The dual effects of host-versus-commensal and host-versus-allograft responses may partially explain why colonized organs have poorer outcomes than sterile organs in the clinic., Introduction Solid organ transplantation is the preferred treatment for end-stage organ failure. Recipients of allogeneic grafts mount immune responses that can lead to transplant rejection, even when hosts are treated [...]

The influence of electrodes on antiferroelectricity and fatigue endurance of 15 nm thick Hf0.2Zr0.8O2 thin films has been studied by a metal–antiferroelectric–metal capacitor structure using TiN and W as electrodes. The W|Hf0.2Zr0.8O2|W capacitor shows significantly enhanced antiferroelectricity and better endurance compared to the capacitor using TiN as the electrode. Assisted by grazing incidence x-ray diffraction and scanning transmission electron microscopy, the different electrical properties are discussed based on the contents of different phases and the diffusion of oxygen from the thin film into electrodes. [ABSTRACT FROM AUTHOR]

Transplantation is the only cure for end-stage organ failure, but without immunosuppression, T cells rapidly reject allografts. While genetic disparities between donor and recipient are major determinants of the kinetics of transplant rejection, little is known about the contribution of environmental factors. Because colonized organs have worse transplant outcome than sterile organs, we tested the influence of host and donor microbiota on skin transplant rejection. Compared with untreated conventional mice, pretreatment of donors and recipients with broad-spectrum antibiotics (Abx) or use of germ-free (GF) donors and recipients resulted in prolonged survival of minor antigen-mismatched skin grafts. Increased graft survival correlated with reduced type I IFN signaling in antigen-presenting cells (APCs) and decreased priming of alloreactive T cells. Colonization of GF mice with fecal material from untreated conventional mice, but not from Abx-pretreated mice, enhanced the ability of APCs to prime alloreactive T cells and accelerated graft rejection, suggesting that alloimmunity is modulated by the composition of microbiota rather than the quantity of bacteria. Abx pretreatment of conventional mice also delayed rejection of major antigen-mismatched skin and MHC class II-mismatched cardiac allografts. This study demonstrates that Abx pretreatment prolongs graft survival, suggesting that targeting microbial constituents is a potential therapeutic strategy for enhancing graft acceptance., Introduction Although solid organ transplantation is the only cure for end-stage organ failure, recognition of the transplanted tissue as foreign invariably leads, in the absence of immunosuppression, to its acute [...]

Ferroelectric resistive switching (RS) devices with functional oxide electrodes allow controlled emergent phenomena at an interface. Here, we demonstrate RS polarity reversal due to ferroelectrically induced phase transition at a doped charge transfer insulator interface. For BiFeO3/Ca0.96Ce0.04MnO3 bilayers grown on a NdAlO3 substrate, by applying voltages to a Ca0.96Ce0.04MnO3 bottom electrode, the resistance changes from a high resistance state (HRS) to a low resistance state (LRS) during a positive voltage cycle (0 → 3 → 0 V), and from a LRS to a HRS during a negative voltage cycle (0 → −3 → 0 V). The RS polarity is completely opposite the expected RS behavior in ferroelectric heterostructures induced by polarization reversal. It is proposed that the unique resistance switching polarity is attributed to the band-filling controlled metal-insulator transition in a Ca0.96Ce0.04MnO3 film, triggered by ferroelectric based electrostatic doping. The results address the importance of ferroelectric field effect on the electronic properties of the interfacial system in ferroelectric/complex oxide-based resistive memory devices. [ABSTRACT FROM AUTHOR]