SIRT4 promotes neuronal apoptosis in models of Alzheimer's disease via the STAT2-SIRT4-mTOR pathway.

Alzheimer's disease (AD) is the leading cause of dementia and presents a considerable disease burden. Its pathology involves substantial neuronal loss, primarily attributed to neuronal apoptosis. Although sirtuin 4 (SIRT4) has been implicated in regulating apoptosis in various diseases, the role of SIRT4 in AD pathology remains unclear. The study used APP/PS1 mice as an animal model of AD and amyloid-ß (Aß)1-42-treated HT-22 cells as an AD cell model. SIRT4 expression was determined by quantitative real-time polymerase chain reaction, Western blot, and immunofluorescence. A Sirt4 knockdown model was established by intracranial injection of lentivirus-packaged sh-SIRT4 and cellular lentivirus transfection. Immunohistochemistry and flow cytometry were used to examine Aß deposition in mice and apoptosis, respectively. Protein expression was assessed by Western blot analysis. The UCSC and JASPAR databases were used to predict upstream transcription factors of Sirt4. Subsequently, the binding of transcription factors to Sirt4 was analyzed using a dual-luciferase assay and chromatin immunoprecipitation. SIRT4 expression was upregulated in both APP/PS1 mice and Aß-treated HT-22 cells compared with their respective control groups. Sirt4 knockdown in animal and cellular models of AD resulted in reduced apoptosis, decreased Aß deposition, and amelioration of learning and memory impairments in mice. Mechanistically, SIRT4 modulates apoptosis via the mTOR pathway and is negatively regulated by the transcription factor signal transducer and activator of transcription 2 (STAT2). Our study findings suggest that targeting the STAT2-SIRT4-mTOR axis may offer a new treatment approach for AD.NEW & NOTEWORTHY The study reveals that in Alzheimer's disease models, SIRT4 expression increases, contributing to neuronal apoptosis and amyloid-ß deposition. Reducing SIRT4 lessens apoptosis and amyloid-ß accumulation, improving memory in mice. This process involves the mTOR pathway, regulated by STAT2 transcription factor. These findings suggest targeting the STAT2-SIRT4-mTOR axis as a potential Alzheimer's treatment strategy.

Prediction of 3-Year Survival in Patients with Cognitive Impairment Based on Demographics, Neuropsychological Data, and Comorbidities: A Prospective Cohort Study.

OBJECTIVES: Based on readily available demographic data, neuropsychological assessment results, and comorbidity data, we aimed to develop and validate a 3-year survival prediction model for patients with cognitive impairment. METHODS: In this prospective cohort study, 616 patients with cognitive impairment were included. Demographic information, data on comorbidities, and scores of the Mini-Mental State Examination (MMSE), Instrumental Activities of Daily Living (IADL) scale, and Neuropsychiatric Inventory Questionnaire were collected. Survival status was determined via telephone interviews and further verified in the official death register in the third year. A 7:3 ratio was used to divide patients into the training and validation sets. Variables with statistical significance (p < 0.05) in the single-factor analysis were incorporated into the binary logistic regression model. A nomogram was constructed according to multivariate analysis and validated. RESULTS: The final cohort included 587 patients, of whom 525 (89.44%) survived and 62 (10.56%) died. Younger age, higher MMSE score, lower IADL score, absence of disinhibition, and Charlson comorbidity index score ≤ 1 were all associated with 3-year survival. These predictors yielded good discrimination with C-indices of 0.80 (0.73-0.87) and 0.85 (0.77-0.94) in the training and validation cohorts, respectively. According to the Hosmer-Lemeshow test results, neither cohort displayed any statistical significance, and calibration curves displayed a good match between predictions and results. CONCLUSIONS: Our study provided further insight into the factors contributing to the survival of patients with cognitive impairment. CLINICAL IMPLICATIONS: Our model showed good accuracy and discrimination ability, and it can be used at community hospitals or primary care facilities that lack sophisticated equipment.

The Neuropsychiatric Changes After COVID-19 Quarantine in Patients With Cognitive Impairment and Their Caregivers in Chongqing, China: A Cohort Study.

BACKGROUND: The follow-up study on neuropsychiatric changes after the lifting of coronavirus disease 2019 (COVID-19) quarantine in patients with cognitive impairment and their caregivers is still lacking, and relative information is needed to formulate more comprehensive healthcare prevention measures worldwide. AIMS: To provide data on the changes in neuropsychiatric performance after the lifting of COVID-19 quarantine in patients with cognitive disorders and their caregivers. METHODS: Two surveys in Chongqing, China were conducted via telephonic interview with 531 patients and their caregivers. The baseline survey was performed from February 11 to 23, 2020, and the follow-up was from October 24 to November 9, 2020. The data of neuropsychiatric symptoms (NPSs), sleep, nutrition, and chronic diseases of patients, as well as the burden of care, anxiety, and depression of caregivers were evaluated. RESULTS: Significant alleviation of NPSs after the lifting of COVID-19 quarantine was observed in patients with mild cognitive impairment (MCI) and dementia (both P < 0.05). Compared with baseline, the prevalence for NPSs of all participants dropped from 57.94 to 38.82%. Among NPS subdomains, apathy displayed the biggest decline at follow-up by 10.72%, followed by nighttime behavior by 8.65%. Mixed effect generalized estimation equation analysis showed significant amelioration in hallucination, depression, apathy, irritability, aberrant motor behavior, and nighttime behavior (all P < 0.05), with the most prominent changes in nighttime behavior and apathy. Among the patients with unsatisfactory control of chronic disease, the medication adherence rate dropped by approximately 30% after the lifting of quarantine. More importantly, around 13% increase of care burden was observed among the caregivers at follow-up, with both depression and anxiety rising by nearly 4%. CONCLUSION: The prolonged quarantine may exacerbate NPS in patients with memory disorders, while the care burden and mental stability of the caregivers after the pandemic should also be concerned.

[The estrogenic effect of formononetin and its effect on the expression of rats' atrium estrogen receptors].

OBJECTIVE: To observe the estrogenic effect of formononetin and its effect on the expressions of atrial estrogen receptor subtypes alpha and beta (ERalpha and ERbeta). METHODS: 50 femal rats were randomly divided into five groups: sham group, model group, nilestriol group, formononetin groups of low and high dose. Rats in sham group were cut a piece of fat before closing the abdomen, the others were ovariectomized. Vaginal exfoliated cell were observed from the fifth day to the tenth after operation to test if the model is successful. The sham and model group were given nomal saline in 10 mL/kg by gavage, the remaining three groups were given nilestriol 2.5 mg/(kg x w), low [20 mg/(kg x d) land high dose [100 mg/(kg x d)) of formononetin by gavage respectively. In the 8th week, vaginal exfoliated cell were observed, then decapitated the rats, removed the uterus, weighed and take wright staining microscopy. The relative expressions of ERalpha and ERbeta of right atrium were detected by RT-PCR. RESULTS: The vaginal cells exhibit a change of estrus after had been fed with high dose of formononetin after 8 weeks. Formononetin increase the uterus coefficient and the expression of atrial ERbeta (P < 0.01), but it dose not have any effect on the expression of ERalpha (P > 0.05). CONCLUSION: Formononetin have estrogenic effect in ovariectomized rats, and it can markedly upregulate the expression of rats' atrial ERbeta.