Alzheimer & Parkinson

The brain is a metabolically vulnerable organ as neurons have both high resting metabolic rates and the need for local rapid conversion of carbon sources to ATP during activity. Midbrain dopamine neurons are thought to be particularly vulnerable to metabolic perturbations, as a subset of these are the first to undergo degeneration in Parkinson's disease, a neurodegenerative disorder long suspected to be in part driven by deficits in mid-brain bioenergetics. In skeletal muscle, energy homeostasis...

Ferroptosis, driven by uncontrolled peroxidation of membrane phospholipids, is distinct from other cell death modalities because it lacks an initiating signal and is surveilled by endogenous antioxidant defenses. Glutathione peroxidase 4 (GPX4) is the guardian of ferroptosis, although its membrane-protective function remains poorly understood. Here, structural and functional analyses of a missense mutation in GPX4 (p.R152H), which causes early-onset neurodegeneration, revealed that this variant...

CONCLUSION: The 95+-year-old population exhibits distinctive patterns of disease burden that have shifted substantially over the past three decades. Despite cross-national differences, cardiometabolic diseases and risk factors, along with multisystem comorbidities from the brain and kidneys, remain the primary drivers. Integrated strategies addressing biological, social, and environmental factors may enhance intrinsic capacity and promote healthy aging in the oldest old.

The role of estradiol in depression and Alzheimer's disease - brain disorders that disproportionately affect females - is debated. Results from observational studies are inconsistent and limited by confounding and reverse causation. To overcome these limitations, we perform two-sample Mendelian randomization. We run genome-wide association studies on sex-specific brain age gap, a proxy of brain health, and female-specific estradiol levels using data from the UK Biobank. We test for causal links...

Auditory gamma stimulation is a promising non-invasive neuromodulation technique for cognitive decline, with preclinical studies demonstrating therapeutic effects in Alzheimer's disease models. However, translating these findings into human trials has produced variable outcomes, suggesting a need to examine factors influencing efficacy. In a systematic review of 62 studies on healthy and cognitively impaired populations, we identified 16 characteristics that may affect the response to...

In this issue of Neuron, Luo et al.¹ report two supramammillary neuronal populations with segregated projections to the dorsal and ventral dentate gyrus that selectively modulate cognitive and emotional processes, respectively. Targeted activation of each pathway alleviates domain-specific behavioral deficits in an Alzheimer's disease mouse model.

Alzheimer's disease (AD) is the most common neurodegenerative disorder associated with dementia. Cellular senescence, widely acknowledged as a key hallmark of aging, has increasingly been recognized as a significant factor in the pathogenesis of AD, although the precise mechanisms underlying this relationship have yet to be fully understood. In the brains of individuals with AD, neurons, glial cells, and cerebrovascular endothelial cells exhibit premature senescence, characterized by...

Major depressive disorder (MDD) is linked to a higher risk of premature aging, but the mechanisms underlying this association remain unclear. Using data from two population cohorts (UK Biobank and Finnish Twin Cohort), we evaluate the relationship between systemic and organ-specific proteomic and epigenetic aging acceleration and MDD. A lifetime history of MDD was associated with accelerated proteomic aging at both systemic and organ-specific levels-including the brain-in both cohorts, with...

Alzheimer's disease (AD) is characterized by progressive cognitive decline, amyloid β (Aβ) deposition, and synaptic dysfunction. However, the mechanisms underlying neurodegeneration remain poorly understood. In this study, we investigated the therapeutic potential of PBX1, a transcriptional regulator implicated in neurodevelopment and neuroprotection, against AD. PBX1 expression was significantly downregulated in postmortem hippocampal tissues from patients with AD and in the APP/PS1 mouse...

Alzheimer's disease (AD) is the predominant cause of cognitive dysfunction, with global prevalence increasing annually. AD progression is principally driven by the accumulation of amyloid-β (Aβ) and hyperphosphorylated microtubule-associated protein tau (p-Tau), which trigger a subsequent cascade of neuroinflammatory responses within the central nervous system (CNS). This pathological cascade is regulated by reciprocal CNS-peripheral immune crosstalk. The brain-spleen axis has emerged as a...

Investigating the cell type organization of hippocampal CA1 is essential for understanding its role in memory and cognition and its susceptibility to neurological disorders like Alzheimer's disease and epilepsy. Multiple studies have identified different organizational principles for gene expression and how it reflects cell types within the CA1 pyramidal layer including gradients or mosaic. Here, we identify sublaminar gene expression patterns within the mouse CA1 pyramidal layer that span...

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Brain aging is a major factor in cognitive decline and Alzheimer's disease (AD) progression. Aging-induced microglial senescence critically drives inflammaging and brain aging processes. Nevertheless, the underlying reasons and mechanisms that promote microglial aging remain unclear. This study explores how 27-hydroxycholesterol (27-OHC), a key oxysterol, accelerates brain aging by promoting microglial senescence, iron overload, and neuroinflammation. Clinically, we observed a significant...

Apolipoprotein E (ApoE) mediates the bidirectional transport of lipids between cells. In the brain, this includes the transfer of lipids from neurons to glia. ApoE4, a major risk factor for Alzheimer's disease, impairs this transport pathway, increasing risk for neurodegeneration. ApoE2 and ApoE3 Christchurch (ApoE3Ch) confer resistance to disease, yet little is known regarding how these variants affect lipid trafficking. Here, we explored how lipoprotein particles containing different ApoE...

Using natural experiments, we have previously reported that live-attenuated herpes zoster (HZ) vaccination appears to have prevented or delayed dementia diagnoses in both Wales and Australia. Here, we find that HZ vaccination also reduces mild cognitive impairment diagnoses and, among patients living with dementia, deaths due to dementia. Exploratory analyses suggest that the effects are not driven by a specific dementia type. Our approach takes advantage of the fact that individuals who had...

Cognitive impairment in people with Parkinson disease (PD) imposes a substantial societal burden: PD affects over 1% of the population aged 65 years and older, and 24-31% of individuals with this condition develop dementia and another 26% present with mild cognitive impairment. Given the increasing prevalence of PD in light of an ageing population, the challenge of PD-associated cognitive impairment is likely to intensify. In this Review, we highlight the latest research advances in...

The Alzheimer's disease (AD) genetic landscape identified microglia as a key disease-modifying cell type. Paired immunoglobulin-like type 2 receptor alpha (PILRA) is an immunoreceptor tyrosine-based inhibitory motif domain-containing inhibitory receptor, expressed by myeloid cells such as microglia. The known protective PILRA G78R gene variant reduces AD risk in apolipoprotein E4 (APOE4) carriers and is enriched in a cohort of healthy centenarians. However, mechanisms underlying protective...

In the later stages of Parkinson's disease, patients often manifest levodopa-induced dyskinesia (LID), compromising their quality of life. The pathophysiology underlying LID is poorly understood, and treatment options are limited. To move toward filling this treatment gap, the intrinsic and synaptic changes in striatal spiny projection neurons (SPNs) triggered by the sustained elevation of dopamine (DA) during dyskinesia were characterized using electrophysiological, pharmacological, molecular,...

Alzheimer's disease (AD) is characterized by progressive memory decline. Converging evidence indicates that hippocampal mRNA translation (protein synthesis) is defective in AD. Here, we show that genetic reduction of the translational repressors, Fragile X messenger ribonucleoprotein (FMRP) or eukaryotic initiation factor 4E (eIF4E)-binding protein 2 (4E-BP2), prevented the attenuation of hippocampal protein synthesis and memory impairment induced by AD-linked amyloid-β oligomers (AβOs) in mice....

Real-time in vivo monitoring of levodopa pharmacokinetics is essential to address its narrow therapeutic window in Parkinson's disease (PD) therapy. However, current methods require excessive sample volumes, suffer low sampling frequencies, and fail to capture complete pharmacokinetic profiles. Here, we present an in vivo monitoring system for real-time tracking of levodopa levels in interstitial fluid (ISF) using a spindle-shaped carbon nanotube (CNT) fiber electrochemical sensor functionalized...