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Science Advances Jun 2024Declined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a...
Declined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a role in memory, but the underlying mechanisms are unknown. Here, we investigate the role of 5-HT 2C receptor (5-HTR) in regulating memory. Transgenic mice expressing a humanized mutation exhibit impaired plasticity of hippocampal ventral CA1 (vCA1) neurons and reduced memory. Further, 5-HT neurons project to and synapse onto vCA1 neurons. Disruption of 5-HT synthesis in vCA1-projecting neurons or deletion of 5-HTRs in the vCA1 impairs neural plasticity and memory. We show that a selective 5-HTR agonist, lorcaserin, improves synaptic plasticity and memory in an AD mouse model. Cumulatively, we demonstrate that hippocampal 5-HTR signaling regulates memory, which may inform the use of 5-HTR agonists in the treatment of dementia.
Topics: Animals; Humans; Receptor, Serotonin, 5-HT2C; Memory; Mice; Mice, Transgenic; Neuronal Plasticity; Alzheimer Disease; Hippocampus; Serotonin; Disease Models, Animal; CA1 Region, Hippocampal; Neurons; Serotonin 5-HT2 Receptor Agonists
PubMed: 38941473
DOI: 10.1126/sciadv.adl2675 -
Science Advances Jun 2024Bile acids (BAs) metabolism has a significant impact on the pathogenesis of Alzheimer's disease (AD). We found that deoxycholic acid (DCA) increased in brains of AD mice...
Bile acids (BAs) metabolism has a significant impact on the pathogenesis of Alzheimer's disease (AD). We found that deoxycholic acid (DCA) increased in brains of AD mice at an early stage. The enhanced production of DCA induces the up-regulation of the bile acid receptor Takeda G protein-coupled receptor (TGR5), which is also specifically increased in neurons of AD mouse brains at an early stage. The accumulation of exogenous DCA impairs cognitive function in wild-type mice, but not in TGR5 knockout mice. This suggests that TGR5 is the primary receptor mediating these effects of DCA. Furthermore, excitatory neuron-specific knockout of TGR5 ameliorates Aβ pathology and cognition impairments in AD mice. The underlying mechanism linking TGR5 and AD pathology relies on the downstream effectors of TGR5 and the APP production, which is succinctly concluded as a "p-STAT3-APH1-γ-secretase" signaling pathway. Our studies identified the critical role of TGR5 in the pathological development of AD.
Topics: Animals; Humans; Mice; Alzheimer Disease; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Brain; Deoxycholic Acid; Disease Models, Animal; Mice, Knockout; Neurons; Receptors, G-Protein-Coupled; Signal Transduction
PubMed: 38941459
DOI: 10.1126/sciadv.ado1855 -
JAMA Network Open Jun 2024Air pollution is a recognized risk factor associated with chronic diseases, including respiratory and cardiovascular conditions, which can lead to physical and cognitive...
IMPORTANCE
Air pollution is a recognized risk factor associated with chronic diseases, including respiratory and cardiovascular conditions, which can lead to physical and cognitive impairments in later life. Although these losses of function, individually or in combination, reduce individuals' likelihood of living independently, little is known about the association of air pollution with this critical outcome.
OBJECTIVE
To investigate associations between air pollution and loss of independence in later life.
DESIGN, SETTING, AND PARTICIPANTS
This cohort study was conducted as part of the Environmental Predictors Of Cognitive Health and Aging study and used 1998 to 2016 data from the Health and Retirement Study. Participants included respondents from this nationally representative, population-based cohort who were older than 50 years and had not previously reported a loss of independence. Analyses were performed from August 31 to October 15, 2023.
EXPOSURES
Mean 10-year pollutant concentrations (particulate matter less than 2.5 μm in diameter [PM2.5] or ranging from 2.5 μm to 10 μm in diameter [PM10-2.5], nitrogen dioxide [NO2], and ozone [O3]) were estimated at respondent addresses using spatiotemporal models along with PM2.5 levels from 9 emission sources.
MAIN OUTCOMES AND MEASURES
Loss of independence was defined as newly receiving care for at least 1 activity of daily living or instrumental activity of daily living due to health and memory problems or moving to a nursing home. Associations were estimated with generalized estimating equation regression adjusting for potential confounders.
RESULTS
Among 25 314 respondents older than 50 years (mean [SD] baseline age, 61.1 [9.4] years; 11 208 male [44.3%]), 9985 individuals (39.4%) experienced lost independence during a mean (SD) follow-up of 10.2 (5.5) years. Higher exposure levels of mean concentration were associated with increased risks of lost independence for total PM2.5 levels (risk ratio [RR] per 1-IQR of 10-year mean, 1.05; 95% CI, 1.01-1.10), PM2.5 levels from road traffic (RR per 1-IQR of 10-year mean, 1.09; 95% CI, 1.03-1.16) and nonroad traffic (RR per 1-IQR of 10-year mean, 1.13; 95% CI, 1.03-1.24), and NO2 levels (RR per 1-IQR of 10-year mean, 1.05; 95% CI, 1.01-1.08). Compared with other sources, traffic-generated pollutants were most consistently and robustly associated with loss of independence; only road traffic-related PM2.5 levels remained associated with increased risk after adjustment for PM2.5 from other sources (RR per 1-IQR increase in 10-year mean concentration, 1.10; 95% CI, 1.00-1.21). Other pollutant-outcome associations were null, except for O3 levels, which were associated with lower risks of lost independence (RR per 1-IQR increase in 10-year mean concentration, 0.94; 95% CI, 0.92-0.97).
CONCLUSIONS AND RELEVANCE
This study found that long-term exposure to air pollution was associated with the need for help for lost independence in later life, with especially large and consistent increases in risk for pollution generated by traffic-related sources. These findings suggest that controlling air pollution could be associated with diversion or delay of the need for care and prolonged ability to live independently.
Topics: Humans; Male; Aged; Female; Air Pollution; Middle Aged; United States; Particulate Matter; Environmental Exposure; Air Pollutants; Cohort Studies; Ozone; Independent Living; Nitrogen Dioxide; Aged, 80 and over; Risk Factors
PubMed: 38941096
DOI: 10.1001/jamanetworkopen.2024.18460 -
Alternative Therapies in Health and... Jun 2024To investigate the effect of icariin (ICA) on cognitive function and NO/cGMP/PKGI signaling pathway in mice with Alzheimer's disease (AD).
OBJECTIVE
To investigate the effect of icariin (ICA) on cognitive function and NO/cGMP/PKGI signaling pathway in mice with Alzheimer's disease (AD).
METHODS
Wild-type C57BL/6 mice were used as the Control group, and APP/PS1 double transgenic mice were used to establish the AD model. The mice were randomly divided into AD group, AD+L-icariin group (10 mg/kg), and AD+H-icariin group (40 mg/kg), with 10 mice in each group. Water maze and Y-maze tests were used to evaluate the learning and memory abilities of mice. ELISA was used to measure the levels of serum Aβ and cGMP. Tunel staining was used to determine the apoptosis of neurons in the hippocampus. Immunohistochemistry was used to measure the expression of Brdu, Dcx, and NeuN in the hippocampus. The protein expressions of iNOS, sGC, PKGI, Caspase3, Bax, and Bcl-2 in brain tissue were determined by Western blot.
RESULTS
Compared with the control group, the learning and memory ability of the AD group was significantly decreased, the serum levels of Aβ and cGMP were increased, the neuronal apoptosis was increased, the contents of Brdu, Dcx and NeuN were decreased, the expression of iNOS, sGC, PKGI, Caspase-3 and Bax proteins was increased, and the expression of Bcl-2 protein was decreased (P < .05). Compared with the AD group, the AD mice treated with icariin (40mg/kg) showed improved learning and memory abilities, decreased serum Aβ and cGMP contents, decreased neuronal apoptosis, increased Brdu, Dcx, and NeuN contents, and decreased iNOS, sGC, PKGI, Caspase-3, and Bax protein expressions. The expression of Bcl-2 protein was increased (P < .05).
CONCLUSION
Icariin improves AD in mice by activating the NO/cGMP/PKGI signaling pathway.
PubMed: 38940779
DOI: No ID Found -
Cancer Medicine Jul 2024Nucleoporin 98 (NUP98) fusion proteins are recurrently found in leukemia and are associated with unfavorable clinical outcomes. They are distributed to the nucleus and...
INTRODUCTION
Nucleoporin 98 (NUP98) fusion proteins are recurrently found in leukemia and are associated with unfavorable clinical outcomes. They are distributed to the nucleus and contribute to leukemogenesis via aberrant transcriptional regulation. We previously identified NUP98-BPTF (NB) fusion in patients with T-cell acute lymphoblastic leukemia (T-ALL) using next-generation sequencing. The FG-repeat of NUP98 and the PHD finger and bromodomain of bromodomain PHD finger transcription factor (BPTF) are retained in the fusion. Like other NUP98 fusion proteins, NB is considered to regulate genes that are essential for leukemogenesis. However, its target genes or pathways remain unknown.
MATERIALS AND METHODS
To investigate the potential oncogenic properties of the NB fusion protein, we lentivirally transduced a doxycycline-inducible NB expression vector into mouse NIH3T3 fibroblasts and human Jurkat T-ALL cells.
RESULTS
NB promoted the transformation of mouse NIH3T3 fibroblasts by upregulating the proto-oncogene Pim1, which encodes a serine/threonine kinase. NB transcriptionally regulated Pim1 expression by binding to its promoter and activated MYC and mTORC1 signaling. PIM1 knockdown or pharmacological inhibition of mTORC1 signaling suppressed NB-induced NIH3T3 cell transformation. Furthermore, NB enhanced the survival of human Jurkat T-ALL cells by inactivating the pro-apoptotic protein BCL2-associated agonist of cell death (BAD).
CONCLUSION
We demonstrated the pivotal role of NB in cell transformation and survival and identified PIM1as a key downstream target of NB. These findings propose a promising therapeutic strategy for patients with NB fusion-positive leukemia.
Topics: Animals; Humans; Mice; Apoptosis; Cell Proliferation; Cell Transformation, Neoplastic; Jurkat Cells; NIH 3T3 Cells; Nuclear Pore Complex Proteins; Oncogene Proteins, Fusion; Proto-Oncogene Mas; Proto-Oncogene Proteins c-pim-1; Transcription Factors; Up-Regulation
PubMed: 38940430
DOI: 10.1002/cam4.7445 -
Bioinformatics (Oxford, England) Jun 2024Electronic health records (EHRs) represent a comprehensive resource of a patient's medical history. EHRs are essential for utilizing advanced technologies such as deep...
MOTIVATION
Electronic health records (EHRs) represent a comprehensive resource of a patient's medical history. EHRs are essential for utilizing advanced technologies such as deep learning (DL), enabling healthcare providers to analyze extensive data, extract valuable insights, and make precise and data-driven clinical decisions. DL methods such as recurrent neural networks (RNN) have been utilized to analyze EHR to model disease progression and predict diagnosis. However, these methods do not address some inherent irregularities in EHR data such as irregular time intervals between clinical visits. Furthermore, most DL models are not interpretable. In this study, we propose two interpretable DL architectures based on RNN, namely time-aware RNN (TA-RNN) and TA-RNN-autoencoder (TA-RNN-AE) to predict patient's clinical outcome in EHR at the next visit and multiple visits ahead, respectively. To mitigate the impact of irregular time intervals, we propose incorporating time embedding of the elapsed times between visits. For interpretability, we propose employing a dual-level attention mechanism that operates between visits and features within each visit.
RESULTS
The results of the experiments conducted on Alzheimer's Disease Neuroimaging Initiative (ADNI) and National Alzheimer's Coordinating Center (NACC) datasets indicated the superior performance of proposed models for predicting Alzheimer's Disease (AD) compared to state-of-the-art and baseline approaches based on F2 and sensitivity. Additionally, TA-RNN showed superior performance on the Medical Information Mart for Intensive Care (MIMIC-III) dataset for mortality prediction. In our ablation study, we observed enhanced predictive performance by incorporating time embedding and attention mechanisms. Finally, investigating attention weights helped identify influential visits and features in predictions.
AVAILABILITY AND IMPLEMENTATION
https://github.com/bozdaglab/TA-RNN.
Topics: Electronic Health Records; Neural Networks, Computer; Humans; Deep Learning; Alzheimer Disease
PubMed: 38940180
DOI: 10.1093/bioinformatics/btae264 -
Frontiers in Bioscience (Landmark... Jun 2024
Topics: Humans; Biomarkers; Dementia; Proteostasis Deficiencies; Protein Folding; Alzheimer Disease
PubMed: 38940055
DOI: 10.31083/j.fbl2906227 -
Frontiers in Bioscience (Landmark... Jun 2024Alzheimer's disease is characterized by extracellular beta-amyloid plaques, intraneuronal tau neurofibrillary tangles and excessive neurodegeneration. The mechanisms of...
BACKGROUND
Alzheimer's disease is characterized by extracellular beta-amyloid plaques, intraneuronal tau neurofibrillary tangles and excessive neurodegeneration. The mechanisms of neuron degeneration and the potential of these neurons to form new nerve fibers for compensation remain elusive. The present study aimed to evaluate the impact of beta-amyloid and tau on new formations of nerve fibers from mouse organotypic brain slices connected to collagen-based microcontact prints.
METHODS
Organotypic brain slices of postnatal day 8-10 wild-type mice were connected to established collagen-based microcontact prints loaded with polyornithine to enhance nerve fiber outgrowth. Human beta-amyloid(42) or P301S mutated aggregated tau was co-loaded to the prints. Nerve fibers were immunohistochemically stained with neurofilament antibodies. The physiological activity of outgrown neurites was tested with neurotracer MiniRuby, voltage-sensitive dye FluoVolt, and calcium-sensitive dye Rhod-4.
RESULTS
Immunohistochemical staining revealed newly formed nerve fibers extending along the prints derived from the brain slices. While collagen-only microcontact prints stimulated nerve fiber growth, those loaded with polyornithine significantly enhanced nerve fiber outgrowth. Beta-amyloid(42) significantly increased the neurofilament-positive nerve fibers, while tau had only a weak effect. MiniRuby crystals, retrogradely transported along these newly formed nerve fibers, reached the hippocampus, while FluoVolt and Rhod-4 monitored electrical activity in newly formed nerve fibers.
CONCLUSIONS
Our data provide evidence that intact nerve fibers can form along collagen-based microcontact prints from mouse brain slices. The Alzheimer's peptide beta-amyloid(42) stimulates this growth, hinting at a neuroprotective function when physiologically active. This "brain-on-chip" model may offer a platform for screening bioactive factors or testing drug effects on nerve fiber growth.
Topics: Animals; Amyloid beta-Peptides; Mice; Nerve Fibers; Brain; tau Proteins; Humans; Immunohistochemistry; Peptide Fragments; Alzheimer Disease; Mice, Inbred C57BL
PubMed: 38940051
DOI: 10.31083/j.fbl2906232 -
Annals of Clinical and Translational... Jun 2024Amyloid-related imaging abnormalities, were originally described by dementia care experts. The wider use of aducanumab and now lecanemab warrant broader understanding by... (Review)
Review
Amyloid-related imaging abnormalities, were originally described by dementia care experts. The wider use of aducanumab and now lecanemab warrant broader understanding by the health care provider continuum. The optimal care approach for patients with Alzheimer's dementia, treated with amyloid-targeted therapy, includes proper clinical diagnosis, complication surveillance, specific imaging protocols, expert specialty consultation, integrated treatment strategies, and proper facility system planning. Improved awareness and understanding of amyloid-modifying therapy, both benefits and potential complications, among the health care provider continuum is paramount to the success of complex care programs. Specifically, recognition of treatment high risk, high benefit groups, and the interface of concurrent antiplatelet and anticoagulation. This integrated acute, specialty, and primary care approach should improve patient care quality and outcome.
PubMed: 38939962
DOI: 10.1002/acn3.52042 -
Sheng Li Xue Bao : [Acta Physiologica... Jun 2024The purpose of the study was to investigate the mechanism of TFEB activator 1 (TA1) improving the autophagic degradation of oligomeric amyloid-β (oAβ) in microglia,...
The purpose of the study was to investigate the mechanism of TFEB activator 1 (TA1) improving the autophagic degradation of oligomeric amyloid-β (oAβ) in microglia, and to explore the therapeutic effect of TA1 on an in vitro model of microglia in Alzheimer's disease (AD). Primary microglia were exposed to 1 μmol/L oAβ for 0, 3, 12, and 24 h respectively to construct the in vitro model of microglia in AD. In order to explore the therapeutic effect of TA1, primary microglia were co-treated with 1 μmol/L oAβ and 1 μmol/L TA1 for 12 h. To determine the autophagy flux, the above cells were further treated with 100 nmol/L Bafilomycin A1 for 1 h before fixation. Fluorescent probes were used to detect the endocytosis or degradation of oAβ by microglia. The autophagic flux was determined by infection of lentivirus mCherry-EGFP-LC3. The nuclear TFEB intensity, the autophagosomes number, and the colocalization ratio of oAβ with lysosome-associated membrane protein 1 (LAMP1) or microtubule-associated protein light chain 3 (LC3), were detected by immunofluorescence assay. Expressions of autophagy-related-genes, including Lamp1, Atg5, and Map1lc3b, were detected by qRT-PCR. Results showed that prolonged oAβ exposure inhibited the endocytosis and degradation of oAβ by microglia. Meanwhile, the number of autophagosomes and autophagy flux in microglia decreased after 12 h of oAβ treatment. We further found that the nuclear expression of autophagy regulator TFEB decreased after 12 h of oAβ exposure, resulting in the decrease of autophagy genes, thus leading to the damage of autophagic degradation of oAβ. Therefore, long-term oAβ exposure was considered to construct the in vitro model of microglia in AD. After TA1 treatment, the nuclear expression of TFEB in cells was obviously upregulated. TA1 treatment upregulated the expressions of autophagy-related genes, leading to the recovery of autophagy flux. TA1 also recovered the endocytosis and degradation of oAβ by microglia. In conclusion, TA1 could improve oAβ clearance by microglia in AD by upregulating microglial TFEB-mediated autophagy, suggesting TA1 as a potential therapeutic drug for AD.
Topics: Microglia; Amyloid beta-Peptides; Autophagy; Animals; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Alzheimer Disease; Cells, Cultured; Mice
PubMed: 38939931
DOI: No ID Found