DDQ anti-aging properties expressed with improved mitophagy in mutant tau HT22 neuronal cells

The purpose of our study is to develop age-related phosphorylated tau (p-tau) inhibitors, for Alzheimer's disease (AD). There are wide-ranging therapeutic molecules available in the market and tested for age-related p-tau inhibition to enhance phosphatase activity and microtubule stability in AD neurons. Until now there are no such small molecules claimed to show promising results to delay the disease process of AD. However, a recently developed molecule, DDQ, has been shown to reduce abnormal protein-protein interactions and protect neurons from mutant protein-induced toxicities in the disease process. In addition, DDQ reduced age- and Aβ-induced oxidative stress, mitochondrial dysfunction, and synaptic toxicity. To date, there are no published reports on the p-tau interaction of DDQ and Sirt3 upregulation with CREB-mediated mitophagy activation in AD neurons. In the current study, HT22 cells were transfected with mutant Tau (mTau) cDNA and treated with the novel molecule DDQ. Cell survival, immunoblotting, and immunofluorescence analysis were conducted to assess cell viability and synaptic and mitophagy proteins in treated and untreated cell groups. As expected, we found cell survival was decreased in mTau-HT22 cells when compared with control HT22 cells. However, cell survival was increased in DDQ-treated mTau-HT22 cells when compared with mTau HT22 cells. P-tau and total tau proteins were significantly reduced in DDQ-treated mTau-HT22 cells, and MAP2 levels were increased. Anti-aging proteins like Sirt3, and CREB levels were increased in DDQ-treated HT22 cells and also in mTau-HT22 cells treated DDQ. Mitophagy proteins were decreased in mTau-HT22 cells and these were increased in DDQ-treated mTau-HT22 cells. These observations strongly suggest that DDQ has anti-p-tau and anti-aging properties, via Sirt3 overexpression and increased mitophagy proteins. Our study findings may have implications for healthy aging to the development of p-tau targeted therapeutics in AD and tauopathies.

Healthy brain aging and delayed dementia in Texas rural elderly

Healthy aging is the process of preserving and enhancing one's independence, physical and mental well-being, and overall quality of life. It involves the mental, emotional, and cognitive wellness. Although biological and genetic factors have a significant influence on the process of aging gracefully, other adjustable factors also play a crucial role. Adopting positive behaviors such as maintaining a nutritious and balanced diet, engaging in regular physical activity, effectively managing stress and anxiety, ensuring sufficient sleep, nurturing spiritual coping mechanisms, and prioritizing overall well-being from an early stage can collectively influence both lifespan and the quality of health during advanced years. We aim to explore the potential impacts of biological, psychosocial, and environmental factors on the process of healthy cognitive aging in individuals who exhibit healthy aging. Additionally, we plan to present initial findings that demonstrate how maintaining good cognitive health during aging could potentially postpone the emergence of neurodegenerative disorders. We hypothesize that there will be strong associations between biological, environmental, and social factors that cause some elderly to be superior in cognitive health than others. For preliminary data collection, we recruited 25 cognitively healthy individuals and 5 individuals with MCI/AD between the ages of 60-90 years. We conducted anthropometric measurements, and blood biomarker testing, administered surveys, and obtained structural brain magnetic resonance imaging (MRI) scans. The Montreal Cognitive Assessment (MoCA) scores and sub-scores for the healthy group were also reported. We found that at baseline, individuals exhibiting healthy cognitive aging, and those with MCI/AD had comparable measures of anthropometrics and blood biomarkers. The healthy group exhibited lower signs of brain volume loss and the ones observed were age-related. Moreover, within the healthy group, there was a significant correlation (p = 0.003) between age and MoCA scores. Conversely, within the individuals with MCI/AD, the MRI scans showed disease signs of grey and white matter and loss of cerebral volume. Healthy brain aging is a scientific area that remains under-explored. Our current study findings support our hypothesis. Future studies are required in diverse populations to determine the various biological, psychological, environmental, lifestyle, and social factors that contribute to it.

Synaptosome microRNAs regulate synapse functions in Alzheimer's disease

MicroRNAs (miRNAs) are found in nerve terminals, synaptic vesicles, and synaptosomes, but it is unclear whether synaptic and cytosolic miRNA populations differ in Alzheimer's disease (AD) or if synaptosomal miRNAs affect AD synapse activity. To address these questions, we generated synaptosomes and cytosolic fractions from postmortem brains of AD and unaffected control (UC) samples and analyzed them using a global Affymetrix miRNAs microarray platform. A group of miRNAs significantly differed (P < 0.0001) with high fold changes variance (+/- >200-fold) in their expressions in different comparisons: (1) UC synaptosome vs UC cytosol, (2) AD synaptosomes vs AD cytosol, (3) AD cytosol vs UC cytosol, and (4) AD synaptosomes vs UC synaptosomes. MiRNAs data analysis revealed that some potential miRNAs were consistently different across sample groups. These differentially expressed miRNAs were further validated using AD postmortem brains, brains of APP transgenic (Tg2576), Tau transgenic (P301L), and wild-type mice. The miR-501-3p, miR-502-3p, and miR-877-5p were identified as potential synaptosomal miRNAs upregulated with disease progression based on AD Braak stages. Gene Ontology Enrichment and Ingenuity Pathway Analysis of synaptosomal miRNAs showed the involvement of miRNAs in nervous system development, cell junction organization, synapse assembly formation, and function of GABAergic synapse. This is the first description of synaptic versus cytosolic miRNAs in AD and their significance in synapse function.

MicroRNA-455-3p improves synaptic, cognitive functions and extends lifespan: Relevance to Alzheimer's disease

BACKGROUND

MicroRNA-455-3p is one of the highly conserved miRNAs involved in multiple cellular functions in humans and we explored its relevance to learning and memory functions in Alzheimer's disease (AD). Our recent in vitro studies exhibited the protective role of miR-455-3p against AD toxicities in reducing full-length APP and amyloid-β (Aβ) levels, and also in reducing defective mitochondrial biogenesis, impaired mitochondrial dynamics and synaptic deficiencies. In the current study, we sought to determine the function of miR-455-3p in mouse models.

METHODS

For the first time we generated both transgenic (TG) and knockout (KO) mouse models of miR-455-3p. We determined the lifespan extension, cognitive function, mitochondrial biogenesis, mitochondrial dynamics, mitochondrial morphology, dendritic spine density, synapse numbers and synaptic activity in miR-455-3p TG and KO mice.

RESULTS

MiR-455-3p TG mice lived 5 months longer than wild-type (WT) counterparts, whereas KO mice lived 4 months shorter than WT mice. Morris water maze test showed improved cognitive behavior, spatial learning and memory in miR-455-3p TG mice relative to age-matched WT mice and miR-455-3p KO mice. Further, mitochondrial biogenesis, dynamics and synaptic activities were enhanced in miR-455-3p TG mice, while these were reduced in KO mice. Overall, overexpressed miR-455-3p in mice displayed protective effects, whereas depleted miR-455-3p in mice exhibited deleterious effects in relation to lifespan, cognitive behavior, and mitochondrial and synaptic activities.

CONCLUSION

Both mouse models could be ideal research tools to understand the molecular basis of aging and its relevance to AD and other age-related diseases.

Defective mitophagy and synaptic degeneration in Alzheimer's disease: Focus on aging, mitochondria and synapse

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by memory loss and multiple cognitive impairments. AD is marked by multiple cellular changes, including deregulation of microRNAs, activation of glia and astrocytes, hormonal imbalance, defective mitophagy, synaptic degeneration, in addition to extracellular neuritic amyloid-beta (Aβ) plaques, phosphorylated tau (P-tau), and intracellular neurofibrillary tangles (NFTs). Recent research in AD revealed that defective synaptic mitophagy leads to synaptic degeneration and cognitive dysfunction in AD neurons. Our critical analyses of mitochondria and Aβ and P-tau revealed that increased levels of Aβ and P-Tau, and abnormal interactions between Aβ and Drp1, P-Tau and Drp1 induced increased mitochondrial fragmentation and proliferation of dysfunctional mitochondria in AD neurons and depleted Parkin and PINK1 levels. These events ultimately lead to impaired clearance of dead and/or dying mitochondria in AD neurons. The purpose of our article is to highlight the recent research on mitochondria and synapses in relation to Aβ and P-tau, focusing on recent developments.

Double-blind comparison of cabergoline and bromocriptine in Parkinson's disease patients with motor fluctuations

In the present study we compared the efficacy and safety of the new dopamine agonist cabergoline (CBG) with bromocriptine (BCR) in Parkinson's disease (PD). CBG has a very long half-life and can be administered as a single daily dose. Forty-four PD patients with uncontrolled motor fluctuations participated in the study. Patients were randomly and blindly assigned to equivalent doses of either CBG or BCR in addition to preexisting levodopa. Dosage was titrated to optimal, using up to 6 mg of CBG or 40 mg of BCR daily. CBG was given as a single morning dose whereas BCR was administered tid. Sixteen patients were followed for 1 year and 16 additional patients for 6 months. The mean follow-up duration was 9 +/- 5 months. The main effect of both drugs was observed on motor UPDRS scores, rigidity, bradykinesia items, and the percentage of awake hours spent during "on" and "off". In general, the effect of CBG was similar to that of BCR. The percentage of awake hours spent during "on" was higher with CBG as compared with BCR. Adverse events included dyskinesias, orthostatism, confusion, edema, and paresthesias in limbs. These effects were seen at similar frequencies with both drugs. The study shows that CBG given as a single morning dose is at least as efficacious as BCR given tid. CBG is a promising dopamine agonist for the treatment of motor fluctuations in PD.

Electroencephalographic findings with low-dose clozapine treatment in psychotic Parkinsonian patients

Twenty patients with Parkinson's disease (PD), who developed delusions and psychotic behavior, underwent electroencephalogram (EEG) recordings before and during treatment with low-dose clozapine. Resolution of the psychotic features was observed in all cases. The EEG was unaltered in 15, whereas five patients exhibited increased generalized or focal slowing when compared with the pretreatment tracings. These findings contrast with the high incidence of EEG abnormalities, including epileptiform activity, which are observed when larger doses of clozapine are used in schizophrenic patients, but they underscore that even in low doses, clozapine may cause EEG changes.

Low-dose clozapine in the treatment of levodopa-induced mental disturbances in Parkinson's disease

Delusions and other manifestations of psychotic behavior are common side effects in Parkinson's disease (PD) patients chronically treated with dopaminergic drugs. Clozapine, a dibenzodiazepine derivative, is an antipsychotic drug largely devoid of extrapyramidal side effects. We evaluated the effects of low doses of clozapine on the mental and motor functions in PD patients requiring antipsychotic treatment. Twenty-seven PD patients taking dopaminergic drugs and who had psychotic behavior received clozapine at 12.5 to 75 mg/d. Fifteen patients received clozapine for 1 to 11 months (mean, 6.8 months) and seven received it for 12 to 24 months (mean, 18 months). No patient exhibited motor deterioration, and the psychotic features disappeared immediately, allowing discontinuation of clozapine after several months in 10 patients. Fifteen patients are still receiving clozapine and are free of psychiatric symptoms. The clozapine treatment was discontinued after 5 days (25 mg/d) in two patients because of somnolence. No patient developed neutropenia. Clozapine in low doses is effective in the treatment of drug-induced delusions and hallucinations in PD.