Alzheimer & Parkinson

The core pathological hallmark of Parkinson's disease (PD) is the progressive degeneration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNpc), driven by misfolding and aggregation of a-synuclein (aSyn) into Lewy bodies. This triggers severe cellular dysfunction, including endoplasmic reticulum (ER) stress and the dysregulation of the unfolded protein response (UPR). TMBIM6, an anti-apoptotic ER protein, inhibits the UPR sensor IRE1a. Although TMBIM6 exhibits...

The physical and social exposome affects human aging, and brain clocks may track its effects. However, most studies neglect multidomain exposures (physical, social and political) across diverse settings globally and their associations with brain aging. In this study, we characterized the associations between 73 country-level physical and social exposomal factors and multimodal brain age in 18,701 participants from 34 countries (healthy individuals and those with Alzheimer's disease,...

Despite advances in understanding the mechanisms, risk factors and treatment strategies for Alzheimer's disease (AD), no approved therapies exist to prevent or delay onset in at-risk individuals or those with elevated biomarkers who do not yet show symptoms. Multiple candidate interventions are now being evaluated in clinical trials in these settings, raising key questions around which populations are most appropriate and what criteria should guide regulatory and clinical decision-making. Data...

The full impact of APOE4 (apolipoprotein E4), the strongest genetic risk factor for Alzheimer's disease (AD), on neuronal and network function remains unclear, particularly during early preclinical stages of disease. Here we show that young APOE4 knockin (E4-KI) mice exhibit hippocampal region-specific network hyperexcitability that predicts later cognitive deficits. This early phenotype arises from cell-type-specific subpopulations of smaller, hyperexcitable neurons and is eliminated by...

Postoperative delirium (POD) accelerates the transition from mild cognitive impairment (MCI) to Alzheimer's disease (AD) in elderly patients. Microglial metabolic reprogramming, a pivotal aspect of the immune-inflammatory response, modulates microglia-neuron interactions and postoperative cognitive function through microenvironmental alterations. Aberrant overexpression of RUVBL2 disrupts metabolic homeostasis, leading to stress granule (SG) aggregation and fibrosis. This study investigated the...

Recent human genetic studies have highlighted the potential role of microglial genes and their regulatory functions in the pathogenesis of Alzheimer's disease (AD). The transcription factor PU.1 (encoded by SPI1) is expressed mainly in microglia in the central nervous system and has been reported to be a genetic risk factor for AD. However, the role of microglial SPI1 in AD etiology is still poorly understood. Here, we demonstrate that the selective deletion of Spi1 in microglia exacerbates...

Rapid advancements in single-cell RNA sequencing (scRNA-seq) technologies revealed the richness of myriad attributes encompassing cell identity. However, the complexity of the data hinders tasks focusing on a specific biological signal. To address this challenge, we introduce bioIB, a framework based on the information bottleneck method, designed to extract an interpretable compressed representation of scRNA-seq data, optimally informative with respect to a specific biological signal, such as...

Neural damage at any level of the neuraxis can lead to urogenital dysfunction, involving the lower urinary tract (LUT) and/or the sexual organs. The LUT consists of the bladder and the urethra (plus the prostate in males); LUT dysfunction can manifest as an underactive bladder, leading to urinary retention, or as an overactive bladder, leading to urinary incontinence. Manifestations of sexual dysfunction include loss of libido and dysfunction of erection, ejaculation and orgasm. In this Review,...

Growing use of p-tau217 raises concerns about testing in healthy people.

The integrated stress response (ISR) is essential for cellular homeostasis and cognitive function. We investigated how persistent ISR activation affects cognitive performance by studying the PPP1R15B^(R658C) genetic variant associated with intellectual disability. To model this condition, we generated a mouse line with the pathogenic allele inserted. This variant destabilized the PPP1R15B•PP1 phosphatase complex, causing persistent ISR activation, impaired protein synthesis, and long-term memory...

The endolysosomal phospholipid bis(monoacylglycerol)phosphate (BMP) is aberrantly elevated in urine from Parkinson's patients carrying mutations in leucine-rich repeat kinase 2 (LRRK2) and glucocerebrosidase (GCase). Because BMP resides on, and regulates biogenesis of, endolysosomal intralumenal membranes that become extracellular vesicles (EVs) upon release, we hypothesized that increased urinary BMP reflects enhanced exocytosis of BMP-enriched EVs. We analyzed BMP metabolism and EV-associated...

Gastrointestinal dysfunction often precedes motor symptoms in Parkinson's disease (PD), suggesting the enteric nervous system (ENS) is central to early pathogenesis. How α-synuclein contributes to ENS dysfunction, and how inflammation modulates this, remains unclear. Here we show that Tumor Necrosis Factor alpha enhances α-synuclein accumulation in induced pluripotent stem cell-derived enteric neurons and glia, and impairs the malate-aspartate shuttle, a key pathway for mitochondrial energy...

Synucleinopathies is an umbrella term for multiple neurological disorders, including Parkinson's disease (PD), Lewy body dementia (LBD), and multiple system atrophy (MSA). A central pathological hallmark of synucleinopathies is the aggregation of α-synuclein (αS, a neuronal protein) and its prion-like spread. Therefore, inhibition of αS aggregation and spread is considered a viable therapeutic approach for the treatment of synucleinopathies. Foldamers are synthetic ligands that mimic the...

Memory-based cognition relies on the integrity of cortico-hippocampal circuits, which are compromised in Alzheimer's disease (AD) as β-amyloid (Aβ) and tau accumulate. However, the mechanisms linking this pathology to circuit dysfunction remain unclear. In mouse models, using in vivo two-photon and Neuropixels recordings, we show that Aβ-tau pathology promotes both region- and layer-specific impairments, involving reduced burst firing in superficial cortical layers and CA1 and reduced mean...

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Neurodegenerative diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD), share overlapping clinical and pathological features. We analyzed cerebrospinal fluid (CSF) and plasma proteomes from 2,705 and 3,009 samples, respectively, across these NDs, identifying disease-specific and shared molecular signatures. CSF showed more disease-associated proteins than plasma, with AD and DLB exhibiting the strongest...

This study aims at implementing a 3D cell culture model of Alzheimer's disease (AD). To that end we engineered human induced pluripotent stem cell (iPSC)-derived neural stem cells to conditionally overexpress FAD mutant APP and PSEN1 variants. After differentiation in 3D basement membrane matrices, cultures exhibited increased Aβ(42) and Aβ(40) levels and a highly pathogenic shift of the Aβ(42/40) ratio. Typical AD phenotypes such as amyloid deposition and tau pathology were observed alongside...

White matter hyperintensities (WMHs) are neuroimaging markers widely interpreted as caused by cerebral small vessel disease, yet emerging evidence suggests that a subset may have a neurodegenerative etiology. Current imaging methods have lacked the specificity to disentangle biological processes underlying WMHs in vivo. Here, we used voxel-level normative modeling and seven microstructural MRI markers with complementary biophysical sensitivities to generate single-subject high-resolution WMH...

Microglia play a major role in the pathophysiology of Parkinson's disease, where they regulate both α-synuclein (αSyn) aggregate clearance and inflammatory responses. Interferon gamma (IFNγ) is a strong immunomodulator, but its role in shaping human microglial phenotypes during αSyn exposure remains incompletely understood. Further, whether the secreted factors from microglia after exposure to αSyn pre-formed fibrils (PFFs) and IFNγ can affect morphology and functionality of dopaminergic neurons...

Multiple system atrophy (MSA) is a progressive neurologic disease, known as an α-synucleinopathy. There are currently no effective disease-modifying therapies for MSA. While neuroinflammation is a hallmark of MSA, the contribution of adaptive immune mechanisms remains poorly understood. Here, we profiled peripheral and central T cell responses in patients with MSA, in comparison with Parkinson's disease (PD) and healthy control cohorts, using single-cell transcriptomics, flow cytometry, and...