Neuroprotective effects of ATPase inhibitory factor 1 preventing mitochondrial dysfunction in Parkinson's disease

Oleanonic acid ameliorates mutant Aβ precursor protein-induced oxidative stress, autophagy deficits, ferroptosis, mitochondrial damage, and ER stress in vitro

Accumulation in the brain of amyloid-β (Aβ), derived from cleavage of Aβ precursor protein (APP), is a hallmark of Alzheimer's disease (AD). Oleanonic acid (OA), a phytochemical from several plants, has proven anti-inflammatory effects, but its role in AD remains unknown. Here we found that OA reduced APP expression and inhibited oxidative stress via Nrf2/HO-1 signaling in SH-SY5Y neuroblastoma cells stably overexpressing APP. OA suppressed phosphorylated mTOR but increased autophagy markers ATG5 and LC3-II. Moreover, OA rescued ferroptosis-related factors GPX4, NCOA, and COX2 and ER stress markers GRP78, CHOP, and three main induction pathways of ER stress including IRE1/XBP1s, PERK/EIF2α, and ATF6. OA alleviated mitochondrial damage through MFN1, MFN2, OPA1, FIS1, and DRP1. Furthermore, OA upregulated GDF11 expression and downregulated phosphorylation of ErbB4 and TrkB without affecting BDNF levels. Thus, OA might protect neurons from APP-induced neurotoxicity by inhibiting oxidative stress, autophagy deficits, ferroptosis, mitochondrial damage, and ER stress in AD, providing a new promising therapeutic strategy in patients with AD.

Plasma Level of ATPase Inhibitory Factor 1 and Intrinsic Capacity in Community-Dwelling Older Adults: Prospective Data From the MAPT Study

BACKGROUND

Intrinsic capacity (IC) is a concept related to functionality that reflects healthy aging. ATPase inhibitory factor 1 (IF1) is a multifaceted protein that regulates mitochondrial oxidative phosphorylation (OXPHOS), and may be involved in IC. The objective of this study is to investigate the association between plasma levels of IF1 and IC changes in community-dwelling older adults.

METHODS

Community-dwelling older adults from the Multidomain Alzheimer Preventive Trial (MAPT Study) were enrolled in this study. A composite IC score was calculated based on 4 IC domains: locomotion, psychological dimension, cognition, and vitality (with data available annually over 4 years of follow-up). Secondary analyses were conducted on the sensory domain (with data available only for 1 year of follow-up). Mixed-model linear regression adjusted for confounders was conducted.

RESULTS

A total of 1 090 participants with usable IF1 values were included in the study (75.3 ± 4.4 years; 64% females). Compared to the lowest quartile, both the low- and high-intermediate IF1 quartiles were found to be cross-sectionally associated with greater composite IC scores across 4 domains (βlow-intermediate, 1.33; 95% confidence interval [CI] 0.06-2.60 and βhigh-intermediate, 1.78; 95% CI 0.49-3.06). In the secondary analyses, the highest quartile was found to be associated with a slower decline in composite IC scores across 5 domains over 1 year (βhigh 1.60; 95% CI 0.06-3.15). The low- and high-intermediate IF1 quartiles were also found to be cross-sectionally associated with greater locomotion (βlow-intermediate, 2.72; 95% CI 0.36-5.08) and vitality scores (βhigh-intermediate, 1.59; 95% CI 0.06-3.12), respectively.

CONCLUSIONS

This study is the first to demonstrate that levels of circulating IF1, a mitochondrial-related biomarker, are associated with IC composite scores in both cross-sectional and prospective analyses among community-dwelling older adults. However, further research is needed to confirm these findings and elucidate the potential underlying mechanisms that may explain these associations.

Regulation of Biomolecular Condensates by Poly(ADP-ribose)

Biomolecular condensates are reversible compartments that form through a process called phase separation. Post-translational modifications like ADP-ribosylation can nucleate the formation of these condensates by accelerating the self-association of proteins. Poly(ADP-ribose) (PAR) chains are remarkably transient modifications with turnover rates on the order of minutes, yet they can be required for the formation of granules in response to oxidative stress, DNA damage, and other stimuli. Moreover, accumulation of PAR is linked with adverse phase transitions in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. In this review, we provide a primer on how PAR is synthesized and regulated, the diverse structures and chemistries of ADP-ribosylation modifications, and protein-PAR interactions. We review substantial progress in recent efforts to determine the molecular mechanism of PAR-mediated phase separation, and we further delineate how inhibitors of PAR polymerases may be effective treatments for neurodegenerative pathologies. Finally, we highlight the need for rigorous biochemical interrogation of ADP-ribosylation in vivo and in vitro to clarify the exact pathway from PARylation to condensate formation.

The interplay of epilepsy with impaired mitophagy and autophagy linked dementia (MAD): A review of therapeutic approaches

The duration and, age of dementia have been linked to a higher risk of seizures. The exact mechanism that drives epileptogenesis in impaired mitophagy and autophagy linked dementia (MAD) is fully defined after reviewing the Scopus, Publon, and Pubmed databases. The epileptogenesis in patients with Alzheimer's disease dementia (ADD) and Parkinson's disease dementia (PDD) is due to involvement of amyloid plaques (Aβ), phosphorylated tau (pTau), Parkin, NF-kB and NLRP3 inflammasome. Microglia, the prime protective and inflammatory cells in the brain exert crosstalk between mitophagy and inflammation. Several researchers believed that the inflammatory brain cells microglia could be a therapeutic target for the treatment of a MAD associated epilepsy. There are conventional antiepileptic drugs such as gabapentin, lamotrigine, phenytoin sodium, carbamazepine, oxcarbazepine, felbamate, lamotrigine, valproate sodium, and topiramate are prescribed by a psychiatrist to suppress seizure frequency. Also, the conventional drugs generate serious adverse effects and synergises dementia characteristics. The adverse effect of carbamazepine is neurotoxic and also, damages haemopoietic system and respiratory tract. The phenytoin treatment causes cerebellar defect and anemia. Dementia and epilepsy have a complicated relationship, thus targeting mitophagy for cure of epileptic dementia makes sense. Complementary and alternative medicine (CAM) is one of the rising strategies by many patients of the world, not only to suppress seizure frequency but also to mitigate dementia characteristics of patients. Therefore our present review focus on the interplay between epilepsy and MAD and their treatment with CAM approaches.