From Analysis:
Circuit-level neural dynamics in neurodegeneration
Analyze circuit-level changes in neurodegeneration using Allen Institute Neural Dynamics data. Focus on: (1) hippocampal circuit disruption, (2) cortical dynamics alterations, (3) sensory processing changes. Identify circuit-based therapeutic targets connecting genes, proteins, and brain regions to neurodegeneration phenotypes.
These hypotheses emerged from the same multi-agent debate that produced this hypothesis.
Parvalbumin-positive (PV+) fast-spiking interneurons in entorhinal cortex layers II-III generate perisomatic gamma oscillations through precisely timed GABA release at basket cell synapses and axon initial segment (AIS) contacts via chandelier cells. In Alzheimer's disease, hyperphosphorylated tau disrupts the subcellular localization of AnkyrinG, a critical scaffolding protein that anchors voltage-gated sodium channel (VGSC) clusters at the AIS of PV interneurons. This tau-mediated AnkyrinG displacement leads to VGSC dispersal and reduced sodium current density, compromising the high-frequency firing capacity essential for gamma rhythmogenesis.
...graph TD
SST["SST gene<br/>somatostatin interneurons"] --> PV["PV+ interneurons<br/>parvalbumin positive"]
PV --> GAMMA_GEN["Gamma oscillation<br/>generation 40Hz"]
GAMMA_GEN --> HIPP_SYNC["Hippocampal<br/>gamma rhythm"]
GAMMA_GEN --> CORT_SYNC["Cortical<br/>gamma rhythm"]
AMYLOID["Amyloid beta<br/>accumulation"] --> GAMMA_RED["Reduced gamma power<br/>40-70% decrease"]
TAU["Tau pathology<br/>neurofibrillary tangles"] --> GAMMA_RED
GAMMA_RED --> DESYNC["Hippocampal-cortical<br/>desynchronization"]
DESYNC --> MEM_IMP["Memory impairment<br/>encoding and retrieval"]
GET["Gamma entrainment<br/>therapy 40Hz"] --> GAMMA_REST["Gamma rhythm<br/>restoration"]
GAMMA_REST --> SYNC_REC["Synchrony recovery<br/>between regions"]
SYNC_REC --> MEM_IMPROVE["Memory function<br/>improvement"]
HIPP_SYNC --> SYNC_NORM["Normal hippocampal-<br/>cortical synchrony"]
CORT_SYNC --> SYNC_NORM
SYNC_NORM --> MEM_NORM["Normal memory<br/>function"]
style SST fill:#ce93d8
style PV fill:#4fc3f7
style GAMMA_GEN fill:#4fc3f7
style HIPP_SYNC fill:#4fc3f7
style CORT_SYNC fill:#4fc3f7
style SYNC_NORM fill:#4fc3f7
style MEM_NORM fill:#4fc3f7
style AMYLOID fill:#ef5350
style TAU fill:#ef5350
style GAMMA_RED fill:#ef5350
style DESYNC fill:#ef5350
style MEM_IMP fill:#ef5350
style GET fill:#81c784
style GAMMA_REST fill:#81c784
style SYNC_REC fill:#ffd54f
style MEM_IMPROVE fill:#ffd54f
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Neuronal and synaptic loss is characteristic in many neurodegenerative diseases, such as frontotemporal dementia and Alzheimer's disease. Recently, we showed that inducing gamma oscillations with visual stimulation (gamma entrainment using sensory stimuli, or GENUS) reduced amyloid plaques and phosphorylated tau in multiple mouse models. Whether GENUS can affect neurodegeneration or cognitive performance remains unknown. Here, we demonstrate that GENUS can entrain gamma oscillations in the visual cortex, hippocampus, and prefrontal cortex in Tau P301S and CK-p25 mouse models of neurodegeneration. Tau P301S and CK-p25 mice subjected to chronic, daily GENUS from the early stages of neurodegeneration showed a preservation of neuronal and synaptic density across multiple brain areas and modified cognitive performance. Our transcriptomic and phosphoproteomic data suggest that chronic GENUS shifts neurons to a less degenerative state, improving synaptic function, enhancing neuroprotective fa
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Influenza infection is substantially worsened by the onset of secondary pneumonia caused by bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). The bidirectional interaction between the influenza-injured lung microenvironment and MRSA is poorly understood. By conditioning MRSA ex vivo in bronchoalveolar lavage fluid collected from mice at various time points of influenza infection, we found that the influenza-injured lung microenvironment dynamically induces MRSA to increase cytotoxin expression while decreasing metabolic pathways. LukAB, a SaeRS two-component system-dependent cytotoxin, is particularly important to the severity of post-influenza MRSA pneumonia. LukAB's activity is likely shaped by the post-influenza lung microenvironment, as LukAB binds to (and is activated by) heparan sulfate (HS) oligosaccharide sequences shed from the epithelial glycocalyx after influenza. Our findings indicate that post-influenza MRSA pneumonia is shaped by bidirectional host-pat
Adenosine monophosphate-activated protein kinase (AMPK) activity is stimulated to promote metabolic adaptation upon energy stress. However, sustained metabolic stress may cause cell death. The mechanisms by which AMPK dictates cell death are not fully understood. We report that metabolic stress promoted receptor-interacting protein kinase 1 (RIPK1) activation mediated by TRAIL receptors, whereas AMPK inhibited RIPK1 by phosphorylation at Ser415 to suppress energy stress-induced cell death. Inhibiting pS415-RIPK1 by Ampk deficiency or RIPK1 S415A mutation promoted RIPK1 activation. Furthermore, genetic inactivation of RIPK1 protected against ischemic injury in myeloid Ampkα1-deficient mice. Our studies reveal that AMPK phosphorylation of RIPK1 represents a crucial metabolic checkpoint, which dictates cell fate response to metabolic stress, and highlight a previously unappreciated role for the AMPK-RIPK1 axis in integrating metabolism, cell death, and inflammation.
BACKGROUND: Both functional brain imaging studies and autopsy reports have indicated the presence of synaptic loss in the brains of depressed patients. The activated microglia may dysfunctionally engulf neuronal synapses, leading to synaptic loss and behavioral impairments in depression. However, the mechanisms of microglial-synaptic interaction under depressive conditions remain unclear. METHODS: We utilized lipopolysaccharide (LPS) to induce a mouse model of depression, examining the effects of LPS on behaviors, synapses, microglia, microglial phagocytosis of synapses, and the C1q/C3-CR3 complement signaling pathway. Additionally, a C1q neutralizing antibody was employed to inhibit the C1q/C3-CR3 signaling pathway and assess its impact on microglial phagocytosis of synapses and behaviors in the mice. RESULTS: LPS administration resulted in depressive and anxiety-like behaviors, synaptic loss, and abnormal microglial phagocytosis of synapses in the hippocampal dentate gyrus (DG) of mi
Parkinson's disease (PD) is a neurodegenerative disease characterized by the death of dopaminergic neurons in the substantia nigra and the formation of Lewy bodies that are composed of aggregated α-synuclein (α-Syn). However, the factors that regulate α-Syn pathology and nigrostriatal dopaminergic degeneration remain poorly understood. Previous studies demonstrate cholesterol 24-hydroxylase (CYP46A1) increases the risk for PD. Moreover, 24-hydroxycholesterol (24-OHC), a brain-specific oxysterol that is catalyzed by CYP46A1, is elevated in the cerebrospinal fluid of PD patients. Herein, we show that the levels of CYP46A1 and 24-OHC are elevated in PD patients and increase with age in a mouse model. Overexpression of CYP46A1 intensifies α-Syn pathology, whereas genetic removal of CYP46A1 attenuates α-Syn neurotoxicity and nigrostriatal dopaminergic degeneration in the brain. Moreover, supplementation with exogenous 24-OHC exacerbates the mitochondrial dysfunction induced by α-Syn fibrils
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Over the past two decades efforts to control malaria have halved the number of cases globally, yet burdens remain high in much of Africa and the elimination of malaria has not been achieved even in areas where extreme reductions have been sustained, such as South Africa1,2. Studies seeking to understand the paradoxical persistence of malaria in areas in which surface water is absent for 3-8 months of the year have suggested that some species of Anopheles mosquito use long-distance migration3. Here we confirm this hypothesis through aerial sampling of mosquitoes at 40-290 m above ground level and provide-to our knowledge-the first evidence of windborne migration of African malaria vectors, and consequently of the pathogens that they transmit. Ten species, including the primary malaria vector Anopheles coluzzii, were identified among 235 anopheline mosquitoes that were captured during 617 nocturnal aerial collections in the Sahel of Mali. Notably, females accounted for more than 80% of a
CRISPR-Cas9 expression independent of its cognate synthetic guide RNA (gRNA) causes widespread genomic DNA damage in human cells. To investigate whether Cas9 can interact with endogenous human RNA transcripts independent of its guide, we perform eCLIP (enhanced CLIP) of Cas9 in human cells and find that Cas9 reproducibly interacts with hundreds of endogenous human RNA transcripts. This association can be partially explained by a model built on gRNA secondary structure and sequence. Critically, transcriptome-wide Cas9 binding sites do not appear to correlate with published genome-wide Cas9 DNA binding or cut-site loci under gRNA co-expression. However, even under gRNA co-expression low-affinity Cas9-human RNA interactions (which we term CRISPR crosstalk) do correlate with published elevated transcriptome-wide RNA editing. Our findings do not support the hypothesis that human RNAs can broadly guide Cas9 to bind and cleave human genomic DNA, but they illustrate a cellular and RNA impact l
PURPOSE: The purpose of this study was to identify if switching from intramuscular (IM) to vaginal progesterone compared to staying on IM progesterone after a positive pregnancy test following embryo transfer (ET) is associated with miscarriage risk. METHODS: A retrospective cohort study was performed in a private university-affiliated fertility clinic and included women aged 18-50 years with a positive pregnancy test following ET. The two groups studied were: women who stayed on IM progesterone following a positive pregnancy test and those who switched to vaginal progesterone after a positive test. The main outcome measured was risk of miscarriage < 24 weeks gestation as a proportion of non-biochemical pregnancies. RESULTS: 1988 women were included in the analysis. Among the baseline characteristics, the presence of prior miscarriages as well as prior failed ETs, and frozen cycles (vs fresh) as type of transfer were associated with IM progesterone use (p values ≤ 0.01). As per miscarr
In mice, social defeat stress (SDS), an ethological model for psychosocial stress, induces sleep. Such sleep could enable resilience, but how stress promotes sleep is unclear. Activity-dependent tagging revealed a subset of ventral tegmental area γ-aminobutyric acid (GABA)-somatostatin (VTAVgat-Sst) cells that sense stress and drive non-rapid eye movement (NREM) and REM sleep through the lateral hypothalamus and also inhibit corticotropin-releasing factor (CRF) release in the paraventricular hypothalamus. Transient stress enhances the activity of VTAVgat-Sst cells for several hours, allowing them to exert their sleep effects persistently. Lesioning of VTAVgat-Sst cells abolished SDS-induced sleep; without it, anxiety and corticosterone concentrations remained increased after stress. Thus, a specific circuit allows animals to restore mental and body functions by sleeping, potentially providing a refined route for treating anxiety disorders.
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An autoimmune process and other environmental factors that destroy pancreatic β cells in the pancreatic islet cells are known to promote the development of insulin-dependent diabetes mellitus (type 1 diabetes) in individuals genetically predisposed to the disease (1). As a consequence of the β cell destruction, the net mass of these cells in the islet cells is reduced and, due to reduced insulin production, maintenance of blood glucose to a proper physiological level is impaired. The most common
Somatostatin (SST) (somatotropin release-inhibiting hormone, somatotropin release-inhibiting factor) is a cyclic disulphide-containing peptide hormone of 14 amino acids (1). SST inhibits hormone secretion, cell proliferation, and promotes apoptosis through binding to specific cell-surface somatostatin receptors (SSTRs) (2). Five SSTR subtypes are identified in the central nervous system (CNS), gastrointestinal tract, and a variety of benign and malignant tumors (2). All subtypes of SSTRs belong
BACKGROUND: Genetic mutations underlying familial Alzheimer's disease (AD) were identified decades ago, but the field is still in search of transformative therapies for patients. While mouse models based on overexpression of mutated transgenes have yielded key insights in mechanisms of disease, those models are subject to artifacts, including random genetic integration of the transgene, ectopic expression and non-physiological protein levels. The genetic engineering of novel mouse models using knock-in approaches addresses some of those limitations. With mounting evidence of the role played by microglia in AD, high-dimensional approaches to phenotype microglia in those models are critical to refine our understanding of the immune response in the brain. METHODS: We engineered a novel App knock-in mouse model (AppSAA) using homologous recombination to introduce three disease-causing coding mutations (Swedish, Arctic and Austrian) to the mouse App gene. Amyloid-β pathology, neurodegenerat
BACKGROUND: A significant proportion of individuals maintain healthy cognitive function despite having extensive Alzheimer's disease (AD) pathology, known as cognitive resilience. Understanding the molecular mechanisms that protect these individuals can identify therapeutic targets for AD dementia. This study aims to define molecular and cellular signatures of cognitive resilience, protection and resistance, by integrating genetics, bulk RNA, and single-nucleus RNA sequencing data across multiple brain regions from AD, resilient, and control individuals. METHODS: We analyzed data from the Religious Order Study and the Rush Memory and Aging Project (ROSMAP), including bulk (n=631) and multi-regional single nucleus (n=48) RNA sequencing. Subjects were categorized into AD, resilient, and control based on β-amyloid and tau pathology, and cognitive status. We identified and prioritized protected cell populations using whole genome sequencing-derived genetic variants, transcriptomic profilin
BACKGROUND: Patient-to-patient variability in the degree to which β-amyloid, tau and neurodegeneration impact cognitive decline in Alzheimer's disease (AD) complicates disease modeling and treatment. However, the underlying mechanisms leading to cognitive resilience are not resolved. We hypothesize that the variability in cognitive function and loss relates to neuronal resilience of the hippocampal GABAergic network. METHODS: We compared TgF344-AD and non-transgenic littermate rats at 9, 12, and 15 months of age. Neurons, β-amyloid plaques and tau inclusions were quantified in hippocampus and entorhinal cortex. Somatostatin (SST) and parvalbumin (PVB) interneurons were traced to examine hippocampal neuroplasticity and cognition was tested in the Barnes maze. RESULTS: The 9-month-old TgF344-AD rats exhibited loss of neurons in the entorhinal cortex and hippocampus. Hippocampal neuronal compensation was observed in 12-month TgF344-AD rats, with upregulation of GABAergic interneuronal mar
BACKGROUND: A significant proportion of individuals maintain cognition despite extensive Alzheimer's disease (AD) pathology, known as cognitive resilience. Understanding the molecular mechanisms that protect these individuals could reveal therapeutic targets for AD. METHODS: This study defines molecular and cellular signatures of cognitive resilience by integrating bulk RNA and single-cell transcriptomic data with genetics across multiple brain regions. We analyzed data from the Religious Order Study and the Rush Memory and Aging Project (ROSMAP), including bulk RNA sequencing (n = 631 individuals) and multiregional single-nucleus RNA sequencing (n = 48 individuals). Subjects were categorized into AD, resilient, and control based on β-amyloid and tau pathology, and cognitive status. We identified and prioritized protected cell populations using whole-genome sequencing-derived genetic variants, transcriptomic profiling, and cellular composition. RESULTS: Transcriptomics and polygenic ri
Alzheimer's disease (AD) is a progressive neurodegenerative disorder and leading cause of dementia, characterized by neuronal and synapse loss, amyloid-β and tau protein aggregates, and a multifactorial pathology involving neuroinflammation, vascular dysfunction, and disrupted metabolism. Additionally, there is growing evidence of imbalance between neuronal excitation and inhibition in the AD brain secondary to dysfunction of parvalbumin (PV)- and somatostatin (SST)-positive interneurons, which differentially modulate neuronal activity. Importantly, impaired interneuron activity in AD may occur upstream of amyloid-β pathology rendering it a potential therapeutic target. To determine the underlying pathologic processes involved in interneuron dysfunction, we spatially profiled the brain transcriptome of the 5XFAD AD mouse model versus controls, across four brain regions, dentate gyrus, hippocampal CA1 and CA3, and cortex, at early-stage (12 weeks-of-age) and late-stage (30 weeks-of-age)
Alzheimer's disease (AD) is a chronic neurodegenerative disease characterized by intracellular formation of neurofibrillary tangles and extracellular deposition of β-amyloid protein (Aβ) in the extracellular matrix. The pathogenesis of AD has not yet been fully elucidated and little is known about global alterations in the brain proteome that are related to AD. To identify and quantify such AD-related changes in the brain, we employed a tandem mass tags approach coupled to high-resolution mass spectrometry. We compared the proteomes of frontal cortex from AD patients with corresponding age-matched brain samples. Liquid chromatography-mass spectrometry/MS analysis carried out on an Orbitrap Fusion Lumos Tribrid mass spectrometer led to identification of 8,066 proteins. Of these, 432 proteins were observed to be significantly altered (>1.5 fold) in their expression in AD brains. Proteins whose abundance was previously known to be altered in AD were identified including secreted phosphopr
The aim of this review is to present data from the available literature concerning CXCL9, CXCL10 and CXCL11, as well as their receptor 3 (CXCR3) in selected diseases of the central nervous system (CNS), such as tickborne encephalitis (TBE), neuroborreliosis (NB), Alzheimer's disease (AD), and multiple sclerosis (MS). CXCL9, CXCL10, and CXCL11 lack glutamic acid-leucine-arginine (ELR), and are unique, because they are more closely related to each other than to any other chemokine. The aforementioned chemokines are especially involved in Th1-type response and in various diseases, as their expression correlates with the tissue infiltration of T cells. Their production is strongly induced by interferon gamma (IFN-υ), the most typical Th1 cytokine. They act by binding to the CXC3 receptor. Knowledge about the action mechanism of CXCR3 and its ligands may be useful in the treatment of CNS diseases. However, data in the literature concerning the evaluation of CXCL9, CXCL10, CXCL11, and their
Reactive gliosis is a hallmark of neuropathology and offers a potential target for addressing numerous neurological diseases. Here, we show that growth arrest and DNA damage inducible gamma (GADD45G), a stress sensor in astrocytes, is a nodal orchestrator of reactive gliosis and neurodegeneration. GADD45G expression in astrocytes is sufficient to incite astrogliosis, microgliosis, synapse loss, compromised animal behavior, and the aggravation of Alzheimer's disease (AD). Conversely, silencing GADD45G specifically in astrocytes preserves synapses and rescues the histological and behavioral phenotypes of AD. Mechanistically, GADD45G controls the mitogen-activated protein kinase kinase kinase 4 (MAP3K4) and neuroimmune signaling pathways, including nuclear factor κB (NF-κB) and interferon regulatory factor 3 (IRF3), leading to profound molecular changes and the secretion of various factors that regulate both cell-autonomous and cell-nonautonomous reactive gliosis and glia-neuron interacti
OBJECTIVE: Polymerase gamma (POLG) mutations are a common cause of mitochondrial disease and have also been linked to neurodegeneration and aging. We studied the molecular mechanisms underlying POLG-related neurodegeneration using postmortem tissue from a large number of patients. METHODS: Clinical information was available from all subjects. Formalin-fixed and frozen brain tissue from 15 patients and 23 controls was studied employing a combination of histopathology, immunohistochemistry, and molecular studies of microdissected neurons. RESULTS: The primary consequence of POLG mutation in neurons is mitochondrial DNA depletion. This was already present in infants with little evidence of neuronal loss or mitochondrial dysfunction. With longer disease duration, we found an additional, progressive accumulation of mitochondrial DNA deletions and point mutations accompanied by increasing numbers of complex I-deficient neurons. Progressive neurodegeneration primarily affected the cerebellar
Mitochondria play a key role in energy production, calcium homeostasis, cell survival, and death. Adverse stimulations including neurodegenerative diseases may result in mitochondrial dynamic imbalance, free radical production, calcium accumulation, intrinsic cell death pathway activation and eventually cell death. Therefore, preserving or promoting mitochondrial function is a potential therapeutic target for the treatment of neurodegenerative disorders. Mitochondrial biogenesis is a process by which new mitochondria are produced from existing mitochondria. This biogenesis process is regulated by Peroxisome proliferator-activated receptor-gamma (PPARγ) coactivator-1alpha (PGC-1α). Once being activated by either phosphorylation or de-acetylation, PGC-1α activates nuclear respiratory factor 1 and 2 (NRF1 and NRF2), and subsequently mitochondrial transcription factor A (Tfam). The activation of this PGC-1α - NRF -Tfam pathway leads to synthesis of mitochondrial DNA and proteins and genera
Impaired glucagon secretion from pancreatic alpha cells is a cause of life-threatening hypoglycemia in individuals with type 1 diabetes (T1D). The mechanisms that lead to defective glucagon secretion remain unclear. Here, we show that the human alpha cell's competence to secrete glucagon depends on paracrine inhibitory input from beta (serotonin [5-HT], γ-aminobutyric acid [GABA]) and delta (somatostatin [SST]) cells. These paracrine signals activate G protein-coupled receptors (GPCRs) that open G protein-gated inwardly rectifying potassium (GIRK) channels, which have a major impact on glucagon secretion. In the absence of this paracrine input, glucagon secretion progressively diminishes until it habituates completely. Strikingly, 5-HT, GABA, and SST restored impaired glucagon secretion in islets from donors with long-duration T1D. These findings indicate that paracrine inhibition is needed to prevent habituation of glucagon secretion. As beta cells are destroyed in T1D, alpha cells lo
RATIONALE: Pain is frequently accompanied by impairments in social behavior; however, the neural circuitry underlying pain-induced social deficits remains poorly understood. The aim of the present study was to delineate the distinct functional roles of γ-aminobutyric acid-releasing (GABAergic) neurons and calcium/calmodulin-dependent protein kinase II-positive (CaMKII+) neurons in the anterior cingulate cortex (ACC) in mediating pain-induced social deficits. METHODS: Mouse models of inflammatory and neuropathic pain were employed. Optogenetic and chemogenetic approaches, combined with fiber photometry, were used to manipulate and monitor the activity of ACC neuronal subtypes. Social behaviors were assessed using the three-chamber social interaction test. Mechanical and thermal pain sensitivity were evaluated using von Frey filaments and the Hargreaves test, respectively. RESULTS: Mice with chronic pain exhibited deficits in social preference and novelty. In vivo calcium imaging reveale
The inferior colliculus (IC) integrates auditory information through a complex interplay of excitatory and inhibitory neurons, and provides both excitatory and inhibitory inputs to the medial geniculate body (MGB). Although IC projection neurons are predominantly glutamatergic, accumulating evidence suggests that they comprised heterogeneous subpopulations with distinct morphological and functional properties. Somatostatin (SST)-expressing neurons represent one such glutamatergic subpopulation; however, their characteristics and circuit organization remain poorly understood. In this study, we examined the projection domains within the MGB and the local circuits of SST-expressing neurons in the IC. SST-expressing neurons in the central nucleus of the IC (CNIC) project mainly to the ventral division of the MGB (MGv) and posterior limiting nucleus (POL), whereas those in the external (ECIC) and dorsal (DCIC) nuclei primarily target the POL. The SST axon terminals in the MGv were large, fo
BACKGROUND: Schizophrenia, one of the most disabling mental disorders, affects approximately seven per 1000 individuals worldwide and has an estimated heritability of around 80%; however, its pathophysiology remains incompletely understood. The disorder has been linked to dysregulation of multiple neurotransmitter systems, including dopamine, serotonin, γ-aminobutyric acid (GABA), and glutamate. GABA, the primary inhibitory neurotransmitter in the central nervous system, is synthesized by the enzymes glutamic acid decarboxylase 67 (GAD67) and glutamic acid decarboxylase 65 (GAD65), encoded by the GAD1 and GAD2 genes, respectively. The genes (SST) and parvalbumin (PVALB) encode somatostatin and parvalbumin, which are characteristic markers of specialized GABAergic interneuron subpopulations involved in maintaining excitatory-inhibitory balance and supporting cortical circuit function. While reduced GAD1 expression has been consistently reported in schizophrenia, findings regarding GAD2
Gestational diabetes mellitus (GDM) can increase the risk for diabetes in offspring, but the mechanisms underlying the effects of intrauterine hyperglycemia (IHG) on the fetus remain unknown. Here, we show that IHG down-regulated DNA demethylases TET2/3 in fetal pancreatic islets, increased DNA methylation of γ-aminobutyric acid (GABA) synthesis gene Gad1, suppressed Gad1 expression, and elevated somatostatin (SST) protein in the pancreas in mice. Pancreas-specific double knockout (DKO) of Tet2/3 recapitulates the IHG effects, causing Gad1 hypermethylation and expression down-regulation, alongside impaired insulin secretion and glucose tolerance. Metabolomic analysis revealed that IHG and Tet2/3 DKO reduced pancreatic GABA content. Gestational dietary GABA supplementation improved metabolic defects in both IHG and Tet2/3 DKO models. scRNA-seq analysis of pancreatic islets showed that IHG or Tet2/3 DKO down-regulated the β cell signature, whereas up-regulating δ cell-related genes, part
Somatostatin (SST) is a neuropeptide widely expressed in the central nervous system, known to exert inhibitory effects through the activation of G protein-coupled somatostatin receptors (SSTRs). Although its synaptic and network-level functions have been implicated in various neurological disorders, the direct peptidergic actions of SST-particularly on microglia-remain poorly understood. Given that SST levels are reduced in Alzheimer's disease (AD) and that microglia predominantly express SSTR2,
BackgroundAlzheimer's disease (AD) brains are characterized by increased levels of the pathogenic amyloid-β (Aβ) peptide, which accumulates into extracellular plaques. Finding a way to lower Aβ levels is fundamental for the prevention and treatment of AD. Neprilysin is the major Aβ degrading enzyme which is regulated by the neuropeptide somatostatin.ObjectiveWe here aimed at identifying the subtype specificity of the five somatostatin receptors (SSTs) expressed in the brain, involved in the regu
Asymptomatic Alzheimer's disease (AsymAD) refers to individuals who, despite exhibiting amyloid-β plaques and tau pathology comparable to Alzheimer's disease (AD), maintain cognitive performance similar to cognitively normal individuals. The resilience mechanism in these AsymAD individual remains understudied. We performed a systematic analysis comparing AsymAD and AD across multiple cohorts (ROSMAP, Banner and Mount Sinai), brain regions (BA6, BA9, BA36 and BA37) and neuronal and glial cell typ
The expression of NPTX2, a neuronal immediate early gene (IEG) essential for excitatory-inhibitory balance, is altered in the earliest stages of cognitive decline that anticipate Alzheimer's disease (AD). Here, we use NPTX2 as a point of reference for Omics studies to identify genes and pathways linked to its position in AD onset and progression. We integrated bulk RNA sequencing from 575 middle temporal gyrus (MTG) samples across four cohorts together with targeted proteomics in the same sample
We aimed to systematically compare alterations in gray matter volume alterations in patients with Alzheimer's disease (AD) and late-life depression (LLD), explore the underlying molecular mechanisms, and provide insights for early identification and targeted intervention strategies. We recruited 33 patients with AD and 38 patients with LLD, along with 40 age- and sex-matched healthy older adults as controls. All participants underwent high-resolution structural MRI at 3.0 Tesla. To analyze gray
Though brain fog is common in Long-coronavirus disease 2019 (Long-COVID), the incidence of mild cognitive impairment (MCI) is unknown. In an observational cohort study, recovered COVID-positive, Long-COVID, and COVID-negative subjects underwent blinded evaluation using National Alzheimer's Coordinating Center (NACC) and National Institute on Aging (NIA) -Alzheimer's Association diagnostic criteria for dementia and MCI. The cumulative incidence of MCI was calculated for each group, and the hazard
BACKGROUND: Tremor is one of the most prevalent symptoms in Parkinson's Disease (PD). The progression and management of tremor in PD can be challenging, as response to dopaminergic agents might be relatively poor, particularly in patients with tremor-dominant PD compared to the akinetic/rigid subtype. In this review, we aim to highlight recent advances in the underlying pathogenesis and treatment modalities for tremor in PD. METHODS: A structured literature search through Embase was conducted using the terms "Parkinson's Disease" AND "tremor" OR "etiology" OR "management" OR "drug resistance" OR "therapy" OR "rehabilitation" OR "surgery." After initial screening, eligible articles were selected with a focus on published literature in the last 10 years. DISCUSSION: The underlying pathophysiology of tremor in PD remains complex and incompletely understood. Neurodegeneration of dopaminergic neurons in the retrorubral area, in addition to high-power neural oscillations in the cerebello-tha
Magnetoencephalography (MEG), a direct measure of neuronal activity, is an underexplored tool in the search for biomarkers of Alzheimer's disease (AD). In this study, we used MEG source estimates of auditory gating generators, nonlinear correlations with neuropsychological results, and multivariate analyses to examine the sensitivity and specificity of gating topology modulation to detect AD. Our results demonstrated the use of MEG localization of a medial prefrontal (mPFC) gating generator as a discrete (binary) detector of AD at the individual level and resulted in recategorizing the participant categories in: (1) controls with mPFC generator localized in response to both the standard and deviant tones; (2) a possible preclinical stage of AD participants (a lower functioning group of controls) in which mPFC activation was localized to the deviant tone only; and (3) symptomatic AD in which mPFC activation was not localized to either the deviant or standard tones. This approach showed
Despite expanding knowledge regarding the role of astroglia in regulating neuronal function, little is known about regional or functional subgroups of brain astroglia and how they may interact with neurons. We use an astroglia-specific promoter fragment in transgenic mice to identify an anatomically defined subset of adult gray matter astroglia. Using transcriptomic and histological analyses, we generate a combinatorial profile for the in vivo identification and characterization of this astroglia subpopulation. These astroglia are enriched in mouse cortical layer V; express distinct molecular markers, including Norrin and leucine-rich repeat-containing G-protein-coupled receptor 6 (LGR6), with corresponding layer-specific neuronal ligands; are found in the human cortex; and modulate neuronal activity. Astrocytic Norrin appears to regulate dendrites and spines; its loss, as occurring in Norrie disease, contributes to cortical dendritic spine loss. These studies provide evidence that hum
Mechanical anisotropy is an essential property for many biomolecules to assume their structures, functions and applications, however, the mechanisms for their direction-dependent mechanical responses remain elusive. Herein, by using a single-molecule nanopore sensing technique, we explore the mechanisms of directional mechanical stability of the xrRNA1 RNA from ZIKA virus (ZIKV), which forms a complex ring-like architecture. We reveal extreme mechanical anisotropy in ZIKV xrRNA1 which highly depends on Mg2+ and the key tertiary interactions. The absence of Mg2+ and disruption of the key tertiary interactions strongly affect the structural integrity and attenuate mechanical anisotropy. The significance of ring structures in RNA mechanical anisotropy is further supported by steered molecular dynamics simulations in combination with force distribution analysis. We anticipate the ring structures can be used as key elements to build RNA-based nanostructures with controllable mechanical anis
BACKGROUND: Gamification refers to the use of game elements in nongame contexts. The use of gamification to change behaviors and promote physical activity (PA) is a promising avenue for tackling the global physical inactivity pandemic and the current prevalence of chronic diseases. However, there is no evidence of the effectiveness of gamified interventions with the existence of mixed results in the literature. OBJECTIVE: The aim of this systematic review and meta-analysis is to evaluate the effectiveness of gamified interventions and their health care potential by testing the generalizability and sustainability of their influence on PA and sedentary behavior. METHODS: A total of 5 electronic databases (PubMed, Embase, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials) were searched for randomized controlled trials published in English from 2010 to 2020. Eligibility criteria were based on the components of the participants, interventions, comparators, and o
BACKGROUND: Nettle is a medicinal plant rich in bioactive molecules. The composition of nettle leaves and stems has been extensively studied, whereas the root has been insufficiently investigated. Therefore, the present study aimed to optimize the parameters of advanced extraction technique, pressurized liquid extraction (PLE), for the lipid fraction of nettle root rich in triterpenoid derivatives and to compare the efficiency of isolation under optimal conditions with conventional Soxhlet extraction (SE). RESULTS: The PLE yields ranged from 0.39-1.63%, whereas the total content of triterpenoid derivatives ranged from 43.50-78.26 mg 100 g-1 , with nine sterols and three pentacyclic triterpenoids identified and quantified within a total range of 42.81-76.57 mg 100 g-1 and 0.69-1.68 mg 100 g-1 dried root, respectively. The most abundant sterol and pentacyclic triterpenoid were β-sitosterol and β-amyrin acetate, with mean values of 50.21 mg 100 g-1 and 0.56 mg 100 g-1 dried root. CONCLUSI
Despite the promising antitumor activity of SHP2 inhibitors in RAS-dependent tumours, overall responses have been limited by their narrow therapeutic window. Like with all MAPK pathway inhibitors, this is likely the result of compensatory pathway activation mechanisms. However, the underlying mechanisms of resistance to SHP2 inhibition remain unknown. The E3 ligase SMURF2 limits TGFβ activity by ubiquitinating and targeting the TGFβ receptor for proteosome degradation. Using a functional RNAi screen targeting all known phosphatases, we identify that the tyrosine phosphatase SHP2 is a critical regulator of TGFβ activity. Specifically, SHP2 dephosphorylates two key residues on SMURF2, resulting in activation of the enzyme. Conversely, SHP2 depletion maintains SMURF2 in an inactive state, resulting in the maintenance of TGFβ activity. Furthermore, we demonstrate that depleting SHP2 has significant implications on TGFβ-mediated migration, senescence, and cell survival. These effects can be
Alzheimer's and Parkinson's diseases are the most prevalent neurodegenerative disorders in aging. Hyposmia has been described as an early symptom that can precede cognitive and motor deficits by decades. Certain regions within the olfactory system, such as the anterior olfactory nucleus, display the neuropathological markers tau and amyloid-β or α-synuclein from the earliest stages of disease progression in a preferential manner. Specific neuronal subpopulations, namely those expressing somatostatin (SST), are preferentially affected throughout the olfactory and limbic systems. SST is a neuropeptide present in a subpopulation of GABAergic interneurons throughout the brain and its main function is to inhibit principal neurons and/or other interneurons. It has been reported that SST expression is reduced by 50% in Alzheimer's disease and that it is related to the formation of Aβ oligomers. The mechanisms underlying the preferential vulnerability of SST-expressing neurons in Alzheimer's d
Among the central features of Alzheimer's disease (AD) progression are altered levels of the neuropeptide somatostatin (SST), and the colocalisation of SST-positive interneurons (SST-INs) with amyloid-β plaques, leading to cell death. In this theoretical review, I propose a molecular model for the pathogenesis of AD based on SST-IN hypofunction and hyperactivity. Namely, hypofunctional and hyperactive SST-INs struggle to control hyperactivity in medial regions in early stages, leading to axonal Aβ production through excessive presynaptic GABAB inhibition, GABAB1a/APP complex downregulation and internalisation. Concomitantly, excessive SST-14 release accumulates near SST-INs in the form of amyloids, which bind to Aβ to form toxic mixed oligomers. This leads to differential SST-IN death through excitotoxicity, further disinhibition, SST deficits, and increased Aβ release, fibrillation and plaque formation. Aβ plaques, hyperactive networks and SST-IN distributions thereby tightly overlap
Amyloids play critical roles in human diseases but have increasingly been recognized to also exist naturally. Shared physicochemical characteristics of amyloids and of their smaller oligomeric building blocks offer the prospect of molecular interactions and crosstalk amongst these assemblies, including the propensity to mutually influence aggregation. A case in point might be the recent discovery of an interaction between the amyloid β peptide (Aβ) and somatostatin (SST). Whereas Aβ is best known for its role in Alzheimer disease (AD) as the main constituent of amyloid plaques, SST is intermittently stored in amyloid-form in dense core granules before its regulated release into the synaptic cleft. This review was written to introduce to readers a large body of literature that surrounds these two peptides. After introducing general concepts and recent progress related to our understanding of amyloids and their aggregation, the review focuses separately on the biogenesis and interactions
Alzheimer's disease (AD) is a progressive neurodegenerative disorder with limited treatment options. Currently approved agents, such as acetylcholinesterase inhibitors and NMDA receptor antagonists, provide only modest symptomatic benefit without modifying disease progression. Increasing evidence highlights the somatostatin (SST) system and its analogues (SSAs) as potential multitarget therapies. Somatostatin receptors (SSTR1-5) are widely expressed in cognition-related brain regions and participate in amyloid-β metabolism, tau phosphorylation, neuroinflammation, and synaptic plasticity. Preclinical studies suggest that SSAs enhance amyloid clearance via neprilysin activation, attenuate tau pathology through PI3K/Akt signaling, regulate APOE4 expression, and modulate microglial function, thereby protecting synaptic integrity. Compared with current monotherapies, SSAs may provide broader therapeutic benefits, particularly if applied in prodromal or early stages of AD. Advances in delive
Impairments in working memory and cognitive flexibility are early and consistent features of both Alzheimer's disease (AD) and stress. These functions depend critically on prefrontal cortical (PFC) circuits, which are particularly vulnerable to neuromodulatory and pathological insults. Recent studies suggest that stress and AD do not simply act globally, but instead converge on specific molecular and cellular targets within distinct neural populations. Notably, both chronic stress and Alzheimer's disease models exhibit dysregulation of synaptic signaling via NR2B-containing NMDA receptors and aberrant GSK-3β activation. These changes often emerge in a cell-type-specific manner, affecting excitatory pyramidal neurons and vulnerable interneuron subtypes such as SST+, PV+, and VIP + cells. The resulting imbalance in excitation and inhibition disrupts the integrity of prefrontal circuits, impairing adaptive behavior. This review synthesizes evidence across molecular, cellular, and circuit
Hippocampal interneurons (INs) play a fundamental role in regulating neural oscillations, modulating excitatory circuits, and shaping spatial representation. While historically overshadowed by excitatory pyramidal cells in spatial coding research, recent advances have demonstrated that inhibitory INs not only coordinate network dynamics but also contribute directly to spatial information processing. This review aims to provide a novel integrative perspective on how distinct IN subtypes participate in spatial coding and how their dysfunction contributes to cognitive deficits in neurological disorders such as epilepsy, Alzheimer's disease (AD), traumatic brain injury (TBI), and cerebral hypoxia-ischemia. We synthesize recent findings demonstrating that different IN classes-including parvalbumin (PV)-, somatostatin (SST)-, cholecystokinin (CCK)-, and calretinin (CR)-expressing neurons-exhibit spatially selective activity, challenging traditional views of spatial representation, and influe
Based on my research of circuit-level neural dynamics in neurodegeneration, I present 6 novel therapeutic hypotheses targeting specific circuit dysfunctions:
Description: Amyloid-β oligomers specifically disrupt somatostatin-positive (SST) and parvalbumin-positive (PV) interneurons, causing differential impairment of theta and gamma oscillations respectively. A dual-target optogenetic therapy could selectively restore SST interneuron function for theta
Based on my analysis of the literature and critical evaluation of these hypotheses, I'll provide a rigorous scientific critique of each:
Specific Weaknesses:
Based on my analysis of drug development landscapes, clinical pipelines, and translational barriers, here's my comprehensive assessment:
| Event | Price | Change | Source | Time | |
|---|---|---|---|---|---|
| ⚖ | Recalibrated | $0.643 | ▼ 2.9% | 2026-04-12 05:13 | |
| ⚖ | Recalibrated | $0.662 | ▼ 2.9% | 2026-04-10 15:53 | |
| 📄 | New Evidence | $0.682 | ▼ 7.3% | evidence_update | 2026-04-09 01:50 |
| 📄 | New Evidence | $0.736 | ▲ 11.1% | evidence_update | 2026-04-09 01:50 |
| ⚖ | Recalibrated | $0.662 | ▼ 2.4% | 2026-04-08 18:39 | |
| ⚖ | Recalibrated | $0.678 | ▲ 0.2% | 2026-04-06 06:48 | |
| ⚖ | Recalibrated | $0.677 | ▲ 0.7% | 2026-04-06 04:06 | |
| ⚖ | Recalibrated | $0.672 | 2026-04-06 04:04 |
Molecular pathway showing key causal relationships underlying this hypothesis
graph TD
PVALB["PVALB"] -->|therapeutic target| Alzheimer_s_disease["Alzheimer's disease"]
h_f8316acf["h-f8316acf"] -->|targets| PVALB_1["PVALB"]
PVALB_2["PVALB"] -->|participates in| Prefrontal_inhibitory_cir["Prefrontal inhibitory circuits"]
PVALB_3["PVALB"] -->|associated with| Alzheimer_s_disease_4["Alzheimer's disease"]
PVALB_5["PVALB"] -->|studied in| neuroscience["neuroscience"]
PVALB_6["PVALB"] -->|promoted: Prefront| Alzheimer_s_disease_7["Alzheimer's disease"]
PVALB_8["PVALB"] -->|expressed in| PV_interneurons["PV_interneurons"]
PVALB_SST["PVALB/SST"] -->|associated with| neuroscience_9["neuroscience"]
PVALB_10["PVALB"] -->|implicated in| neurodegeneration["neurodegeneration"]
BDNF["BDNF"] -->|co associated with| PVALB_11["PVALB"]
PVALB_12["PVALB"] -->|co associated with| SST["SST"]
PVALB_13["PVALB"] -->|associated with| alzheimer_s_disease["alzheimer_s_disease"]
PVALB_14["PVALB"] -->|involved in| prefrontal_inhibitory_cir["prefrontal_inhibitory_circuits"]
CAMK2A["CAMK2A"] -->|co associated with| PVALB_SST_15["PVALB/SST"]
CHAT["CHAT"] -->|co associated with| PVALB_SST_16["PVALB/SST"]
style PVALB fill:#ce93d8,stroke:#333,color:#000
style Alzheimer_s_disease fill:#ef5350,stroke:#333,color:#000
style h_f8316acf fill:#4fc3f7,stroke:#333,color:#000
style PVALB_1 fill:#ce93d8,stroke:#333,color:#000
style PVALB_2 fill:#ce93d8,stroke:#333,color:#000
style Prefrontal_inhibitory_cir fill:#81c784,stroke:#333,color:#000
style PVALB_3 fill:#ce93d8,stroke:#333,color:#000
style Alzheimer_s_disease_4 fill:#ef5350,stroke:#333,color:#000
style PVALB_5 fill:#ce93d8,stroke:#333,color:#000
style neuroscience fill:#4fc3f7,stroke:#333,color:#000
style PVALB_6 fill:#ce93d8,stroke:#333,color:#000
style Alzheimer_s_disease_7 fill:#ef5350,stroke:#333,color:#000
style PVALB_8 fill:#ce93d8,stroke:#333,color:#000
style PV_interneurons fill:#4fc3f7,stroke:#333,color:#000
style PVALB_SST fill:#ce93d8,stroke:#333,color:#000
style neuroscience_9 fill:#ef5350,stroke:#333,color:#000
style PVALB_10 fill:#ce93d8,stroke:#333,color:#000
style neurodegeneration fill:#ef5350,stroke:#333,color:#000
style BDNF fill:#ce93d8,stroke:#333,color:#000
style PVALB_11 fill:#ce93d8,stroke:#333,color:#000
style PVALB_12 fill:#ce93d8,stroke:#333,color:#000
style SST fill:#ce93d8,stroke:#333,color:#000
style PVALB_13 fill:#ce93d8,stroke:#333,color:#000
style alzheimer_s_disease fill:#ef5350,stroke:#333,color:#000
style PVALB_14 fill:#ce93d8,stroke:#333,color:#000
style prefrontal_inhibitory_cir fill:#81c784,stroke:#333,color:#000
style CAMK2A fill:#ce93d8,stroke:#333,color:#000
style PVALB_SST_15 fill:#ce93d8,stroke:#333,color:#000
style CHAT fill:#ce93d8,stroke:#333,color:#000
style PVALB_SST_16 fill:#ce93d8,stroke:#333,color:#000
neuroscience | 2026-04-03 | completed