White adipose tissue is a highly specialized organ that not only stores excess calories but also helps control systemic energy and glucose metabolism as an active endocrine organ. Fu et al.’s new study in Cell Research explains how secretory peptide neurotensin via interaction with its receptor in white adipocytes regulates food intake.
Organ transplantation is the last-resort option to treat organ failure. However, less than 10% of patients benefit from this only option due to lack of major histocompatibility complex (MHC)-matched donor organs and 25%–80% of donated organs could not find MHC-matched recipients. T cell allorecognition is the principal mechanism for allogeneic graft rejection. We herein present a “donor MHC-specific thymus vaccination” (DMTV) strategy to induce T cell tolerance to both autologous and allogeneic donor MHC. Allogeneic MHC molecules were expressed in the recipient thymus through adeno-associated virus-mediated delivery, which led to stable expression of allogeneic MHC together with the autologous MHC in the engineered thymus. During local T cell education, those T cells recognizing either autologous MHC or allogeneic MHC were equally depleted. We constructed C57BL/6-MHC and BALB/c-MHC dual immunocompatible mice via thymus vaccination of C57BL/6-MHC into the BALB/c thymus and observed long-term graft tolerance after transplantation of C57BL/6 skin and C57BL/6 mouse embryonic stem cells into the vaccinated BALB/c mice. We also validated our DMTV strategy in a bone marrow, liver, thymus (BLT)-humanized mouse model for immunocompatible allotransplantation of human embryonic stem cells. Our study suggests that the DMTV strategy is a potent avenue to introduce a donor compatible immune system in recipients, which overcomes the clinical dilemma of the extreme shortage of MHC-matched donor organs for treating patients with end-stage organ failure.
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During learning experience, a subset of astrocytes in the hippocampus is activated and becomes both necessary and sufficient for subsequent memory recall. Williamson et al. discovered that these learning-associated astrocytes play an important role in memory by modulating engram neurons’ synaptic activity and facilitating the reactivation of engram neuron ensembles during memory retrieval.