Transethnic analysis identifies SORL1 variants and haplotypes protective against Alzheimer's disease.

Introduction: The SORL1 locus exhibits protective effects against Alzheimer's disease (AD) across ancestries, yet systematic studies in diverse populations are sparse.

Methods: Logistic regression identified AD-associated SORL1 haplotypes in East Asian (N = 5249) and European (N = 8588) populations. Association analysis between SORL1 haplotypes and AD-associated traits or plasma biomarkers was conducted.

The noncoding circular RNA regulates developmental experience-dependent plasticity in mouse visual cortex.

Circular RNAs (circRNAs) are noncoding RNAs abundant in brain tissue, and many are derived from activity-dependent, linear mRNAs encoding for synaptic proteins, suggesting that circRNAs may directly or indirectly play a role in regulating synaptic development, plasticity, and function. However, it is unclear if the circular forms of these RNAs are similarly regulated by activity and what role these circRNAs play in developmental plasticity. Here, we employed transcriptome-wide analysis comparing differential expression of both mRNAs and circRNAs in juvenile mouse primary visual cortex (V1) following monocular deprivation (MD), a model of developmental plasticity.

Using blood transcriptome analysis for Alzheimer's disease diagnosis and patient stratification.

Introduction: Blood protein biomarkers demonstrate potential for Alzheimer's disease (AD) diagnosis. Limited studies examine the molecular changes in AD blood cells.

Methods: Bulk RNA-sequencing of blood cells was performed on AD patients of Chinese descent (n = 214 and 26 in the discovery and validation cohorts, respectively) with normal controls (n = 208 and 38 in the discovery and validation cohorts, respectively).

A blood-based multi-pathway biomarker assay for early detection and staging of Alzheimer's disease across ethnic groups.

Introduction: Existing blood-based biomarkers for Alzheimer's disease (AD) mainly focus on its pathological features. However, studies on blood-based biomarkers associated with other biological processes for a comprehensive evaluation of AD status are limited.

Methods: We developed a blood-based, multiplex biomarker assay for AD that measures the levels of 21 proteins involved in multiple biological pathways.

Neuronal γ-secretase regulates synaptic functions via cholesterol homeostasis.

In this issue of Neuron, Essayan-Perez and Südhof demonstrate roles for γ-secretase in the regulation of synaptic functions in human neurons. Chronic attenuation of γ-secretase activity increases synapse formation but decreases neurotransmission (i.e.

The VCAM1-ApoE pathway directs microglial chemotaxis and alleviates Alzheimer's disease pathology.

In Alzheimer's disease (AD), sensome receptor dysfunction impairs microglial danger-associated molecular pattern (DAMP) clearance and exacerbates disease pathology. Although extrinsic signals, including interleukin-33 (IL-33), can restore microglial DAMP clearance, it remains largely unclear how the sensome receptor is regulated and interacts with DAMP during phagocytic clearance. Here, we show that IL-33 induces VCAM1 in microglia, which promotes microglial chemotaxis toward amyloid-beta (Aβ) plaque-associated ApoE, and leads to Aβ clearance.

Receptor-ligand interaction controls microglial chemotaxis and amelioration of Alzheimer's disease pathology.

Microglia maintain brain homeostasis through their ability to survey and phagocytose danger-associated molecular patterns (DAMPs). In Alzheimer's disease (AD), microglial phagocytic clearance regulates the turnover of neurotoxic DAMPs including amyloid beta (Aβ) and hyperphosphorylated tau. To mediate DAMP clearance, microglia express a repertoire of surface receptors to sense DAMPs; the activation of these receptors subsequently triggers a chemotaxis-to-phagocytosis functional transition in microglia.

An IL1RL1 genetic variant lowers soluble ST2 levels and the risk effects of APOE-ε4 in female patients with Alzheimer's disease.

Changes in the levels of circulating proteins are associated with Alzheimer's disease (AD), whereas their pathogenic roles in AD are unclear. Here, we identified soluble ST2 (sST2), a decoy receptor of interleukin-33-ST2 signaling, as a new disease-causing factor in AD. Increased circulating sST2 level is associated with more severe pathological changes in female individuals with AD.

Deep learning-based polygenic risk analysis for Alzheimer's disease prediction.

Background: The polygenic nature of Alzheimer's disease (AD) suggests that multiple variants jointly contribute to disease susceptibility. As an individual's genetic variants are constant throughout life, evaluating the combined effects of multiple disease-associated genetic risks enables reliable AD risk prediction. Because of the complexity of genomic data, current statistical analyses cannot comprehensively capture the polygenic risk of AD, resulting in unsatisfactory disease risk prediction.

Multi-Omics-Based Autophagy-Related Untypical Subtypes in Patients with Cerebral Amyloid Pathology.

Recent multi-omics analyses paved the way for a comprehensive understanding of pathological processes. However, only few studies have explored Alzheimer's disease (AD) despite the possibility of biological subtypes within these patients. For this study, unsupervised classification of four datasets (genetics, miRNA transcriptomics, proteomics, and blood-based biomarkers) using Multi-Omics Factor Analysis+ (MOFA+), along with systems-biological approaches following various downstream analyses are performed.

Demographics and Medication Use of Patients with Late-Onset Alzheimer's Disease in Hong Kong.

Background: Alzheimer's disease (AD) is the most common cause of dementia in the elderly population. However, epidemiological studies on the demographics of AD in Hong Kong population are lacking.

Objective: We investigated the demographics, comorbidities, mortality rates, and medication use of patients with AD in Hong Kong to understand how the disease has been managed locally.

Association of SPI1 Haplotypes with Altered SPI1 Gene Expression and Alzheimer's Disease Risk.

Background: Genetic studies reveal that single-nucleotide polymorphisms (SNPs) of SPI1 are associated with Alzheimer's disease (AD), while their effects in the Chinese population remain unclear.

Objective: We aimed to examine the AD-association of SPI1 SNPs in the Chinese population and investigate the underlying mechanisms of these SNPs in modulating AD risk.

Methods: We conducted a genetic analysis of three SPI1 SNPs (i.

Rhynchophylline Administration Ameliorates Amyloid-β Pathology and Inflammation in an Alzheimer's Disease Transgenic Mouse Model.

Alzheimer's disease (AD), the most common neurodegenerative disease, has limited treatment options. As such, extensive studies have been conducted to identify novel therapeutic approaches. We previously reported that rhynchophylline (Rhy), a small molecule EphA4 inhibitor, rescues impaired hippocampal synaptic plasticity and cognitive dysfunctions in APP/PS1 mice, an AD transgenic mouse model.

Brain-wide Cas9-mediated cleavage of a gene causing familial Alzheimer's disease alleviates amyloid-related pathologies in mice.

The pathology of familial Alzheimer's disease, which is caused by dominant mutations in the gene that encodes amyloid-beta precursor protein (APP) and in those that encode presenilin 1 and presenilin 2, is characterized by extracellular amyloid plaques and intracellular neurofibrillary tangles in multiple brain regions. Here we show that the brain-wide selective disruption of a mutated APP allele in transgenic mouse models carrying the human APP Swedish mutation alleviates amyloid-beta-associated pathologies for at least six months after a single intrahippocampal administration of an adeno-associated virus that encodes both Cas9 and a single-guide RNA that targets the mutation. We also show that the deposition of amyloid-beta, as well as microgliosis, neurite dystrophy and the impairment of cognitive performance, can all be ameliorated when the CRISPR-Cas9 construct is delivered intravenously via a modified adeno-associated virus that can cross the blood-brain barrier.

IL-33/ST2 Signaling Regulates Synaptic Plasticity and Homeostasis in the Adult Hippocampal Circuitry.

In response to neuronal activity changes, the adult hippocampal circuits undergo continuous synaptic remodeling, which is essential for information processing, learning, and memory encoding. Glial cells, including astrocytes and microglia, actively regulate hippocampal synaptic plasticity by coordinating the neuronal activity-induced synaptic changes at the circuit level. Emerging evidence suggests that the crosstalk between neurons and glia in the adult hippocampus is region specific and that the mechanisms controlling this process are critically dependent on secreted factors.

Large-scale plasma proteomic profiling identifies a high-performance biomarker panel for Alzheimer's disease screening and staging.

Introduction: Blood proteins are emerging as candidate biomarkers for Alzheimer's disease (AD). We systematically profiled the plasma proteome to identify novel AD blood biomarkers and develop a high-performance, blood-based test for AD.

Methods: We quantified 1160 plasma proteins in a Hong Kong Chinese cohort by high-throughput proximity extension assay and validated the results in an independent cohort.

Instructive roles of astrocytes in hippocampal synaptic plasticity: neuronal activity-dependent regulatory mechanisms.

In the adult hippocampus, synaptic plasticity is important for information processing, learning, and memory encoding. Astrocytes, the most common glial cells, play a pivotal role in the regulation of hippocampal synaptic plasticity. While astrocytes were initially described as a homogenous cell population, emerging evidence indicates that in the adult hippocampus, astrocytes are highly heterogeneous and can differentially respond to changes in neuronal activity in a subregion-dependent manner to actively modulate synaptic plasticity.

Polygenic Score Models for Alzheimer's Disease: From Research to Clinical Applications.

The high prevalence of Alzheimer's disease (AD) among the elderly population and its lack of effective treatments make this disease a critical threat to human health. Recent epidemiological and genetics studies have revealed the polygenic nature of the disease, which is possibly explainable by a polygenic score model that considers multiple genetic risks. Here, we systemically review the rationale and methods used to construct polygenic score models for studying AD.

Cytokine signaling convergence regulates the microglial state transition in Alzheimer's disease.

Genetic analyses have revealed the pivotal contribution of microglial dysfunctions to the pathogenesis of Alzheimer's disease (AD). Along AD progression, the accumulation of danger-associated molecular patterns (DAMPs) including beta-amyloid and hyperphosphorylated tau continuously stimulates microglia, which results in their chronic activation. Chronically activated microglia secrete excessive pro-inflammatory cytokines, which further regulate microglial responses towards DAMPs.

Melanocortin receptor activation alleviates amyloid pathology and glial reactivity in an Alzheimer's disease transgenic mouse model.

Alzheimer's disease (AD) is a devastating neurodegenerative disorder with no disease-modifying treatment. AD progression is characterized by cognitive decline, neuroinflammation, and accumulation of amyloid-beta (Aβ) and neurofibrillary tangles in the brain, leading to neuronal and glial dysfunctions. Neuropeptides govern diverse pathophysiological processes and represent key players in AD pathogenesis, regulating synaptic plasticity, glial cell functions and amyloid pathology.

Efficient manipulation of gene dosage in human iPSCs using CRISPR/Cas9 nickases.

The dysregulation of gene dosage due to duplication or haploinsufficiency is a major cause of autosomal dominant diseases such as Alzheimer's disease. However, there is currently no rapid and efficient method for manipulating gene dosage in a human model system such as human induced pluripotent stem cells (iPSCs). Here, we demonstrate a simple and precise method to simultaneously generate iPSC lines with different gene dosages using paired Cas9 nickases.

Quantitative assessment of amyloid-beta phagocytic capacity in an Alzheimer's disease mouse model.

Alzheimer's disease is characterized by the deposition of extracellular amyloid-beta (Aβ) plaques. While microglial phagocytosis is a major mechanism through which Aβ is cleared, there is no method for quantitatively assessing Aβ phagocytic capacity of microglia . Here, we present a flow cytometry-based method for investigating the Aβ phagocytic capacity of microglia .