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The timing and characteristics of neuronal death in Alzheimer’s disease (AD) remain largely unknown. Here we examine AD mouse models with an original marker, myristoylated alanine-rich C-kinase substrate phosphorylated at serine 46 (pSer46-MARCKS), and reveal an increase of neuronal necrosis during pre-symptomatic phase and a subsequent decrease during symptomatic phase. Postmortem brains of mild cognitive impairment (MCI) rather than symptomatic AD patients reveal a remarkable increase of necrosis. In vivo imaging reveals instability of endoplasmic reticulum (ER) in mouse AD models and genome-edited human AD iPS cell-derived neurons. The level of nuclear Yes-associated protein (YAP) is remarkably decreased in such neurons under AD pathology due to the sequestration into cytoplasmic amyloid beta (Aβ) aggregates, supporting the feature of YAP-dependent necrosis. Suppression of early-stage neuronal death by AAV-YAPdeltaC reduces the later-stage extracellular Aβ burden and cognitive impairment, suggesting that preclinical/prodromal YAP-dependent neuronal necrosis represents a target for AD therapeutics., The precise mechanisms of neuronal cell death in neurodegeneration are not fully understood. Here the authors show that YAP-mediated neuronal necrosis is increased in pre-symptomatic stages of Alzheimer’s disease and intervention to the necrosis rescues extracellular Aβ aggregation and symptoms in a mouse model.

To understand the molecular processes that link Aβ amyloidosis, tauopathy and neurodegeneration, we screened for tau-interacting proteins by immunoprecipitation/LC-MS. We identified the carboxy-terminal PDZ ligand of nNOS (CAPON) as a novel tau-binding protein. CAPON is an adaptor protein of neuronal nitric oxide synthase (nNOS), and activated by the N-methyl-D-aspartate receptor. We observed accumulation of CAPON in the hippocampal pyramidal cell layer in the AppNL-G-F -knock-in (KI) brain. To investigate the effect of CAPON accumulation on Alzheimer’s disease (AD) pathogenesis, CAPON was overexpressed in the brain of AppNL-G-F mice crossbred with MAPT (human tau)-KI mice. This produced significant hippocampal atrophy and caspase3-dependent neuronal cell death in the CAPON-expressing hippocampus, suggesting that CAPON accumulation increases neurodegeneration. CAPON expression also induced significantly higher levels of phosphorylated, oligomerized and insoluble tau. In contrast, CAPON deficiency ameliorated the AD-related pathological phenotypes in tauopathy model. These findings suggest that CAPON could be a druggable AD target., To understand the molecular processes that link Aβ amyloidosis, tauopathy and neurodegeneration, the authors screened for tau-interacting proteins. They demonstrated that a novel tau binding protein CAPON accelerates tau pathology and neuronal cell death in an Alzheimer’s disease mouse model.

To study the contribution of putative perforin-independent mechanism in the antigen-specific target destruction by cytotoxic T lymphocytes CD8+ CTL lines were established from spleen cells of chimeric mice produced by injecting perforin (-/-) embryonic stem cells into blastocysts of RAG-2(-/-) mice. When tested on normal concanavalin A blasts, these perforin-deficient cytotoxic T lymphocyte lines were found to be capable of inducing antigen-specific target cell lysis accompanied by DNA degradation. In contrast, with target cells carrying a mutation in Fas molecule, perforin-independent cytotoxicity was not detectable. These data not only confirmed the primary role of perforin but simultaneously revealed a major contribution of a perforin-independent Fas-mediated pathway in antigen-specific cytolysis.

The objective of this study is to design biodegradable hydrogels for the controlled release of low-molecular-weight heparin (LMWH) and evaluate the biological activity. Gelatin was cationized by chemically introducing ethylene diamine into the carboxyl groups in different conditions to obtain cationized gelatins. The cationized gelatin was mixed with the LMWH in aqueous solution to form the complex. Gelatin, together with the complex of LMWH and cationized gelatin, was dehydrothermally cross-linked for different time periods to prepare the gelatin hydrogel-incorporating complex. The hydrogel-incorporating complex was neither degraded in phosphate-buffered saline solution (PBS) at 37 °C nor did it release the LMWH complex. When placed in PBS containing collagenase, the hydrogel was enzymatically degraded to release the LMWH complex. The time profile of hydrogel degradation and the LMWH release depended on the condition of hydrogel cross-linking. The longer the cross-linking time period, the slower the hydrogel degradation and the subsequent LMWH release. The half-life period of LMWH release was in good correspondence with that of hydrogel degradation. It is possible that the LMWH was released as the result of hydrogel degradation. When applied to the mouse model of abdominal membrane fibrosis, the hydrogel system of LMWH release showed a promising anti-fibrotic effect.

We demonstrate that lck promoter-driven conditional expression of transgenic SPA-1, a Rap GTPase-activation protein, causes a profound defect of alphabeta T-cell development at the CD4/CD8 double-negative (DN) stage due to enhanced cell death without affecting gammadelta T-cell development. The effect was specific to the DN stage, because CD4 promoter-driven SPA-1 expression hardly affected T-cell development. Rap1A17, a dominant-negative Rap mutant, interfered with the generation of double-positive (DP) cells from Rag2(-/-) fetal thymocytes in vitro in the presence of anti-CD3epsilon antibody and Notch ligand. Rap GTPases were activated in a DN cell line by the expression of self-oligomerizing CD3 (CD8:CD3epsilon chimera), which substituted autonomous pre-T-cell receptor (TCR) signal, inducing CD69 expression and CD25 down-regulation. Reciprocally, expression of C3G, a Rap guanine nucleotide exchange factor, in both normal and Rag2(-/-) DN cells markedly enhanced Notch-dependent generation and expansion of DP cells without additional anti-CD3epsilon antibody, thus bypassing pre-TCR. Defective alphabeta T-cell development in the conditional SPA-1-transgenic mice was restored completely by introducing a p53(-/-) mutation. These results suggest that endogenous Rap GTPases downstream of pre-TCR play an essential role in rescuing pre-T cells from the p53-mediated checkpoint response, thus allowing Notch-mediated expansion and differentiation.

Macrophage-inducible C-type lectin (Mincle) is expressed mainly in macrophages and is induced after exposure to various stimuli and stresses. Here we show that Mincle selectively associated with the Fc receptor common gamma-chain and activated macrophages to produce inflammatory cytokines and chemokines. Mincle-expressing cells were activated in the presence of dead cells, and we identified SAP130, a component of small nuclear ribonucloprotein, as a Mincle ligand that is released from dead cells. To investigate whether Mincle is required for normal responses to cell death in vivo, we induced thymocyte death by irradiating mice and found that transient infiltration of neutrophils into the thymus could be blocked by injection of Mincle-specific antibody. Our results suggest that Mincle is a receptor that senses nonhomeostatic cell death and thereby induces the production of inflammatory cytokines to drive the infiltration of neutrophils into damaged tissue.

The relationship between activation-induced growth inhibition and regulation of the cell cycle progression was investigated in T cell hybridomas by studying the function of the cell cycle-regulating genes such as G1 cyclins and their associated kinases. Activation of T cell hybridomas by anti-T cell receptor antibody induces growth arrest at G1 phase of the cell cycle and subsequently results in activation-driven cell death. Rapid reduction of both messenger RNA and protein level of the cyclin D3 is accompanied by growth arrest upon activation. Although the residual cyclin D3 protein forms a complex with cdk4 protein, cyclin D3-dependent kinase activity is severely impaired. Stable transfectants engineered to express cyclin D3 override the growth arrest upon activation. These results imply that the activation signal through T cell receptor induces the down-regulation of cyclin D3 expression and cyclin D3-dependent kinase activity, leading to growth arrest in G1 phase of the cell cycle in T cells.