HMGB1 signaling phosphorylates Ku70 and impairs DNA damage repair in Alzheimer's disease pathology.

DNA damage is increased in Alzheimer's disease (AD), while the underlying mechanisms are unknown. Here, we employ comprehensive phosphoproteome analysis, and identify abnormal phosphorylation of 70 kDa subunit of Ku antigen (Ku70) at Ser77/78, which prevents Ku70-DNA interaction, in human AD postmortem brains. The abnormal phosphorylation inhibits accumulation of Ku70 to the foci of DNA double strand break (DSB), impairs DNA damage repair and eventually causes transcriptional repression-induced atypical cell death (TRIAD). Cells under TRIAD necrosis reveal senescence phenotypes. Extracellular high mobility group box 1 (HMGB1) protein, which is released from necrotic or hyper-activated neurons in AD, binds to toll-like receptor 4 (TLR4) of neighboring neurons, and activates protein kinase C alpha (PKCα) that executes Ku70 phosphorylation at Ser77/78. Administration of human monoclonal anti-HMGB1 antibody to post-symptomatic AD model mice decreases neuronal DSBs, suppresses secondary TRIAD necrosis of neurons, prevents escalation of neurodegeneration, and ameliorates cognitive symptoms. TRIAD shares multiple features with senescence. These results discover the HMGB1-Ku70 axis that accounts for the increase of neuronal DNA damage and secondary enhancement of TRIAD, the cell death phenotype of senescence, in AD.

Analyses of Nivolumab Exposure and Clinical Safety Between 3-mg/kg Dosing and 240-mg Flat Dosing in Asian Patients with Advanced Renal Cell Carcinoma in the Real-World Clinical Setting.

We aimed to identify the clinical characteristics related to increased nivolumab exposure in Japanese patients with renal cell carcinoma (RCC) in real-world clinical setting. Eleven patients were treated with the originally approved nivolumab dosing regimen of 3 mg/kg every 2 weeks (Q2W) (3-mg/kg group) and 8 patients with a flat dose of 240 mg Q2W (flat dosing group). Trough concentrations (Cmin) until the fifth cycle were measured by sandwich enzyme-linked immunosorbent assay using anti-nivolumab monoclonal antibody established by the Autonomously Diversifying Library system. Mean Cmin at four cycles of nivolumab were significantly higher in the flat dosing group than in the 3-mg/kg group. In an analysis of covariates related to nivolumab concentration, serum albumin (Alb) was significantly lower in the 3-mg/kg group than in the flat dose group. Cmin correlated significantly with serum Alb at all cycles. In conclusion, serum Alb was a potential clinically relevant covariate for nivolumab pharmacokinetics in Japanese RCC patients. Further studies should verify whether serum Alb affects nivolumab efficacy and toxicity.