NPTX2 and cognitive dysfunction in Alzheimer's Disease

NPTX2 transfection improves synaptic E/I balance and performance in learning impaired aged rats

Excessive neural activity in the medial temporal lobe commonly associates with cognitive decline in elderly humans and also in rodents.An attractive model pathway to study synaptic mechanisms underlying age-dependent circuit hyperexcitability is the connection made by lateral entorhinal cortex cells onto the dentate gyrus (LEC→DG). Both structures are particularly affected by age and, importantly, in behaviorally characterized aged rats, learning impairment correlates with diminished feedforward inhibition of granule cells recruited by LEC inputs. In this rat model of aging, we evaluated how overexpression of Neuronal Pentraxin 2 (NPTX2) in the LEC, essential for stabilizing excitatory inputs onto fast-spiking inhibitory interneurons (FS-INs), enhances feedforward inhibition and improves spatial memory in impaired individuals. In addition, we found that FS-INs from unimpaired aged individuals have an increased excitatory drive compared to young individuals. These findings support the notion that NPTX2-mediated compensatory mechanisms to enhance the recruitment of FS-INs are crucial to maintaining proficient memory performance during aging.

Biofluid biomarker changes following treatment with sabirnetug (ACU193) in INTERCEPT-AD, a phase 1 trial in early Alzheimer's disease

OBJECTIVE

Sabirnetug (ACU193) is a humanized monoclonal antibody selective for soluble amyloid beta oligomers (AβOs), synaptotoxins that are early and persistent triggers of Alzheimer's disease (AD). Sabirnetug pharmacodynamics were examined in the INTERCEPT-AD phase 1 study in mild cognitive impairment and mild dementia due to AD (NCT04931459) using biofluid biomarkers associated with Aβ and tau pathology, synaptic dysfunction, neuroinflammation, and neurodegeneration.

METHODS

INTERCEPT-AD was a randomized, first-in-human study of sabirnetug versus placebo administered as a single (SAD; 2, 10, 25, 60 mg/kg) or multiple (MAD; three doses of 10 or 60 mg/kg every 4 weeks [Q4W] or 25 mg/kg Q2W) ascending doses. Biomarkers were measured pre-/post-dose in CSF and EDTA-plasma. Correlations of biomarker changes versus dose, exposure duration, and target engagement were determined.

RESULTS

In MAD cohorts, CSF pTau181 decreased significantly (60 mg/kg Q4W, p = 0.049). VAMP2 decreased significantly at all doses (p ≤ 0.041); neurogranin decreased significantly at 60 mg/kg Q4W (p = 0.037). Aβ1-42/Aβ1-40 trended upward with sabirnetug dose. Aβ1-42/Aβ1-40 and neurogranin changes correlated with sabirnetug-AβO target engagement (p ≤ 0.01). Decreases in tTau, VAMP2, and neurogranin correlated with exposure duration (p ≤ 0.007). Plasma pTau181, pTau217, GFAP, and NfL trended lower.

DISCUSSION

Following three sabirnetug doses, changes in CSF and plasma biomarkers were observed. The CSF biomarker response increased with increasing dose and exposure duration, consistent with previous reports that sabirnetug reaches the central compartment and engages its AβO target. The ongoing phase 2 ALTITUDE-AD study (NCT06335173) will test whether sabirnetug's pharmacodynamic effects can be substantiated with a larger sample size and longer treatment duration.

Unbiased CSF Proteomics in Patients With Idiopathic Normal Pressure Hydrocephalus to Identify Molecular Signatures and Candidate Biomarkers

BACKGROUND AND OBJECTIVES

Idiopathic normal pressure hydrocephalus (iNPH) is a reversible neurologic disorder that remains poorly understood. Accurate differential diagnosis of iNPH and Alzheimer disease (AD) is complicated by overlapping clinical manifestations. Beyond neuroimaging, there are currently no biomarkers available for iNPH leading to frequent misdiagnosis, and proteomic studies into iNPH have been limited by low sample sizes and inadequate analytical depth. In this study, we report the results of a large-scale proteomic analysis of CSF from patients with iNPH to elucidate pathogenesis and identify potential disease biomarkers.

METHODS

CSF samples were collected through lumbar puncture during diagnostic visits to the Mass General Brigham neurology clinic. Samples were analyzed using mass spectrometry. Differential expression of proteins was studied using linear regression models. Results were integrated with publicly available single-nucleus transcriptomic data to explore potential cellular origins. Biological process enrichment was analyzed using gene-set enrichment analyses. To identify potential diagnostic biomarkers, decision tree-based machine learning algorithms were applied.

RESULTS

Participants were classified as cognitively unimpaired (N = 53, mean age: 66.5 years, 58.5% female), AD (N = 124, mean age: 71.2 years, 46.0% female), or iNPH (N = 44, mean age: 74.6 years, 34.1% female) based on clinical diagnosis and AD biomarker status. Gene Ontology analyses indicated upregulation of the immune system and coagulation processes and downregulation of neuronal signaling processes in iNPH. Differential expression analysis showed a general downregulation of proteins in iNPH. Integration of differentially expressed proteins with transcriptomic data indicated that changes likely originated from neuronal, endothelial, and glial origins. Using machine learning algorithms, a panel of 12 markers with high diagnostic potential for iNPH were identified, which were not all detected using univariate linear regression models. These markers spanned the various molecular processes found to be affected in iNPH, such as LTBP2, neuronal pentraxin receptor (NPTXR), and coagulation factor 5.

DISCUSSION

Leveraging the etiologic insights from a typical neurologic clinical cohort, our results indicate that processes of immune response, coagulation, and neuronal signaling are affected in iNPH. We highlight specific markers of potential diagnostic interest. Together, our findings provide novel insights into the pathophysiology of iNPH and may facilitate improved diagnosis of this poorly understood disorder.

Applying machine learning to high-dimensional proteomics datasets for the identification of Alzheimer's disease biomarkers

PURPOSE

This study explores the application of machine learning to high-dimensional proteomics datasets for identifying Alzheimer's disease (AD) biomarkers. AD, a neurodegenerative disorder affecting millions worldwide, necessitates early and accurate diagnosis for effective management.

METHODS

We leverage Tandem Mass Tag (TMT) proteomics data from the cerebrospinal fluid (CSF) samples from the frontal cortex of patients with idiopathic normal pressure hydrocephalus (iNPH), a condition often comorbid with AD, with rare access to both lumbar and ventricular samples. Our methodology includes extensive data preprocessing to address batch effects and missing values, followed by the use of the Synthetic Minority Over-sampling Technique (SMOTE) for data augmentation to overcome the small sample size. We apply linear, and non-linear machine learning models, and ensemble methods, to compare iNPH patients with and without biomarker evidence of AD pathology ( A β - T - or A β + T + ) in a classification task.

RESULTS

We present a machine learning workflow for working with high-dimensional TMT proteomics data that addresses their inherent data characteristics. Our results demonstrate that batch effect correction has no or minor impact on the models' performance and robust feature selection is critical for model stability and performance, especially in the high-dimensional proteomics data setting for AD diagnostics. The results further indicated that removing features with missing values produced stronger models than imputing them, and the batch effect had minimal impact on the models Our best-performing disease-progression detection model, a random forest, achieves an AUC of 0.84 (± 0.03).

CONCLUSION

We identify several novel protein biomarkers candidates, such as FABP3 and GOT1, with potential diagnostic value for AD pathology detection, suggesting the necessity of different biomarkers for AD diagnoses for patients with iNPH, and considering different biomarkers for ventricular and lumbar CSF samples. This work underscores the importance of a meticulous machine learning process in enhancing biomarker discovery. Our study also provides insights in translating biomarkers from other central nervous system diseases like iNPH, and both ventricular and lumbar CSF samples for biomarker discovery, providing a foundation for future research and clinical applications.

Non-coding transcriptome profiles in clear-cell renal cell carcinoma

Clear-cell renal cell carcinoma (ccRCC) is a common urological malignancy with an increasing incidence. The development of molecular biomarkers that can predict the response to treatment and guide personalized therapy selection would substantially improve patient outcomes. Dysregulation of non-coding RNA (ncRNA) has been shown to have a role in the pathogenesis of ccRCC. Thus, an increasing number of studies are being carried out with a focus on the identification of ncRNA biomarkers in ccRCC tissue samples and the connection of these markers with patients' prognosis, pathological stage and grade (including metastatic potential), and therapy outcome. RNA sequencing analysis led to the identification of several ncRNA biomarkers that are dysregulated in ccRCC and might have a role in ccRCC development. These ncRNAs have the potential to be prognostic and predictive biomarkers for ccRCC, with prospective applications in personalized treatment selection. Research on ncRNA biomarkers in ccRCC is advancing, but clinical implementation remains preliminary owing to challenges in validation, standardization and reproducibility. Comprehensive studies and integration of ncRNAs into clinical trials are essential to accelerate the clinical use of these biomarkers.

Path integration impairments reveal early cognitive changes in Subjective Cognitive Decline

Path integration, the ability to track one's position using self-motion cues, is critically dependent on the grid cell network in the entorhinal cortex, a region vulnerable to early Alzheimer's disease pathology. In this study, we examined path integration performance in individuals with subjective cognitive decline (SCD), a group at increased risk for Alzheimer's disease, and healthy controls using an immersive virtual reality task. We developed a Bayesian computational model to decompose path integration errors into distinct components. SCD participants exhibited significantly higher path integration error, primarily driven by increased memory leak, while other modelling-derived error sources, such as velocity gain, sensory and reporting noise, remained comparable across groups. Our findings suggest that path integration deficits, specifically memory leak, may serve as an early marker of neurodegeneration in SCD and highlight the potential of self-motion-based navigation tasks for detecting pre-symptomatic Alzheimer's disease-related cognitive changes.

Teaser

Virtual reality, computational modelling, and biomarkers uncover path integration deficits, distinguishing pre-symptomatic Alzheimer's from normal aging.

Biomarkers of synaptic degeneration in Alzheimer's disease

Synapse has been considered a critical neuronal structure in the procession of Alzheimer's disease (AD), attacked by two pathological molecule aggregates (amyloid-β and phosphorylated tau) in the brain, disturbing synaptic homeostasis before disease manifestation and subsequently causing synaptic degeneration. Recently, evidence has emerged indicating that soluble oligomeric amyloid-β (AβO) and tau exert direct toxicity on synapses, causing synaptic damage. Synaptic degeneration is closely linked to cognitive decline in AD, even in the asymptomatic stages of AD. Therefore, the identification of novel, specific, and sensitive biomarkers involved in synaptic degeneration holds significant promise for early diagnosis of AD, reducing synaptic degeneration and loss, and controlling the progression of AD. Currently, a range of biomarkers in cerebrospinal fluid (CSF), such as synaptosome-associated protein 25 (SNAP-25), synaptotagmin-1, growth-associated protein-43 (GAP-43), and neurogranin (Ng), along with functional brain imaging techniques, can detect variations in synaptic density, offering high sensitivity and specificity for AD diagnosis. However, these methods face challenges, including invasiveness, high cost, and limited accessibility. In contrast, biomarkers found in blood or urine provide a minimally invasive, cost-effective, and more accessible alternative to traditional diagnostic methods. Notably, neuron-derived exosomes in blood, which contain synaptic proteins, show variations in concentration that can serve as indicators of synaptic injury, providing an additional, less invasive approach to AD diagnosis and monitoring.

Gamma-glutamyl transferase 5 overexpression in cerebrovascular endothelial cells improves brain pathology, cognition, and behavior in APP/PS1 mice

JOURNAL/nrgr/04.03/01300535-202502000-00030/figure1/v/2024-05-28T214302Z/r/image-tiff In patients with Alzheimer's disease, gamma-glutamyl transferase 5 (GGT5) expression has been observed to be downregulated in cerebrovascular endothelial cells. However, the functional role of GGT5 in the development of Alzheimer's disease remains unclear. This study aimed to explore the effect of GGT5 on cognitive function and brain pathology in an APP/PS1 mouse model of Alzheimer's disease, as well as the underlying mechanism. We observed a significant reduction in GGT5 expression in two in vitro models of Alzheimer's disease (Aβ1-42-treated hCMEC/D3 and bEnd.3 cells), as well as in the APP/PS1 mouse model. Additionally, injection of APP/PS1 mice with an adeno-associated virus encoding GGT5 enhanced hippocampal synaptic plasticity and mitigated cognitive deficits. Interestingly, increasing GGT5 expression in cerebrovascular endothelial cells reduced levels of both soluble and insoluble amyloid-β in the brains of APP/PS1 mice. This effect may be attributable to inhibition of the expression of β-site APP cleaving enzyme 1, which is mediated by nuclear factor-kappa B. Our findings demonstrate that GGT5 expression in cerebrovascular endothelial cells is inversely associated with Alzheimer's disease pathogenesis, and that GGT5 upregulation mitigates cognitive deficits in APP/PS1 mice. These findings suggest that GGT5 expression in cerebrovascular endothelial cells is a potential therapeutic target and biomarker for Alzheimer's disease.

Exploring the Relationship Between Serum Neuronal Pentraxin 2 and Poststroke Cognitive Impairment in Patients With First-Episode Acute Ischemic Stroke

BACKGROUND AND OBJECTIVE

Neuronal pentraxin 2 (NPTX2) is associated with cognitive impairment in some neurodegenerative diseases. However, few studies focused on the association between NPTX2 and poststroke cognitive impairment (PSCI). Hence, this study aimed to investigate the association between serum NPTX2 levels and PSCI.

METHODS

A total of 134 participants with acute ischemic stroke (AIS) and 42 normal controls were enrolled in this study. Admission baseline information was collected, and serum NPTX2 levels were determined within 24 h using enzyme-linked immunosorbent assay (ELISA) at hospital admission. All subjects were evaluated for cognitive function using the MoCA (Montreal Cognitive Assessment) scale at 3 months after stroke onset, and patients with AIS were divided into PSCI and PSNCI (poststroke no cognitive impairment) groups, with a total MoCA score < 26 defined as PSCI. This study analyzed the relationship between serum NPTX2 and MoCA score and the risk factors of PSCI. The receiver operating characteristic (ROC) curve was to evaluate the diagnostic value of serum NPTX2 levels on PSCI.

RESULTS

Among the 134 AIS participants, 53 (38.8%) patients suffered from PSCI at 3 months after stroke onset. The serum levels of NPTX2 in the PSCI group, PSNCI group, and normal controls group were significantly different (p < 0.05). The serum NPTX2 levels in the PSCI and PSNCI groups were higher than normal control group, and the serum NPTX2 levels in the PSCI group were lower than PSNCI group (p < 0.05). Serum NPTX2 levels were positively correlated with the total score of MoCA (r = 0.329, p < 0.01), and also positively correlated with some subcognitive domains of MoCA (visuospatial and executive functions, naming, delayed memory, and attention). ROC curve indicated that serum NPTX2 predicted cognitive impairment in AIS patients. Multivariate Logistic regression analysis indicated serum NPTX2 was an independent protective factor for PSCI (odds ratio [OR] = 0.075, 95% CI 0.010-0.812, p < 0.01).

CONCLUSIONS

Lower serum NPTX2 levels were associated with PSCI within 3 months in patients with first-episode AIS. Lower levels of serum NPTX2 may be associated with impairment in visuospatial and executive functions, naming, delayed memory, and attention, while a further larger-scale study is needed to verify our findings.

Fast-spiking parvalbumin-positive interneurons: new perspectives of treatment and future challenges in dementia

Central nervous system parvalbumin-positive interneurons (PV-INs) are crucial and highly vulnerable to various stressors. They also play a significant role in the pathological processes of many neuropsychiatric diseases, especially those associated with cognitive impairment, such as Alzheimer's disease (AD), vascular dementia (VD), Lewy body dementia, and schizophrenia. Although accumulating evidence suggests that the loss of PV-INs is associated with memory impairment in dementia, the precise molecular mechanisms remain elusive. In this review, we delve into the current evidence regarding the physiological properties of PV-INs and summarize the latest insights into how their loss contributes to cognitive decline in dementia, particularly focusing on AD and VD. Additionally, we discuss the influence of PV-INs on brain development, the variations in their characteristics across different types of dementia, and how their loss affects the etiology and progression of cognitive impairments. Ultimately, our goal is to provide a comprehensive overview of PV-INs and to consider their potential as novel therapeutic targets in dementia treatment.

Biomarker treatment effects in two phase 3 trials of gantenerumab

INTRODUCTION

We report biomarker treatment effects in the GRADUATE I and II phase 3 studies of gantenerumab in early Alzheimer's disease (AD).

METHODS

Amyloid and tau positron emission tomography (PET), volumetric magnetic resonance imaging (vMRI), cerebrospinal fluid (CSF), and plasma biomarkers used to assess gantenerumab treatment related changes on neuropathology, neurodegeneration, and neuroinflammation over 116 weeks.

RESULTS

Gantenerumab reduced amyloid PET load, CSF biomarkers of amyloid beta (Aβ)40, total tau (t-tau), phosphorylated tau 181 (p-tau181), neurogranin, S100 calcium-binding protein B (S100B), neurofilament light (NfL), alpha-synuclein (α-syn), neuronal pentraxin-2 (NPTX2), and plasma biomarkers of t-tau, p-tau181, p-tau217, and glial fibrillary acidic protein (GFAP) while increasing plasma Aβ40, Aβ42. vMRI showed increased reduction in whole brain volume and increased ventricular expansion, while hippocampal volume was unaffected. Tau PET showed no treatment effect.

DISCUSSION

Robust treatment effects were observed for multiple biomarkers in GRADUATE I and II. Comparison across anti-amyloid antibodies indicates utility of p-tau and GFAP as biomarkers of amyloid plaque removal while NfL and tau PET seem unsuitable as consistent indicators of clinical efficacy. vMRI might be confounded by non-neurodegenerative brain volume changes. TRIAL REGISTRATION NUMBER (CLINICALTRIALS.GOV IDENTIFIER): NCT03444870 and NCT03443973.

HIGHLIGHTS

Gantenerumab significantly reduced brain amyloid load. Tau positron emission tomography showed no treatment effect in a small subset of participants. Volumetric magnetic resonance imaging showed increased whole brain volume reduction under treatment while hippocampal volume was unaffected. Robust treatment effects on cerebrospinal fluid and plasma biomarkers were found, despite lack of clinical efficacy.

Proteomic Insight Into Alzheimer's Disease Pathogenesis Pathways

Alzheimer's disease (AD) is a leading cause of dementia, but the pathogenesis mechanism is still elusive. Advances in proteomics have uncovered key molecular mechanisms underlying AD, revealing a complex network of dysregulated pathways, including amyloid metabolism, tau pathology, apolipoprotein E (APOE), protein degradation, neuroinflammation, RNA splicing, metabolic dysregulation, and cognitive resilience. This review examines recent proteomic findings from AD brain tissues and biological fluids, highlighting potential biomarkers and therapeutic targets. By examining the proteomic landscape of them, we aim to deepen our understanding of the disease and support developing precision medicine strategies for more effective interventions.

Analyzing the potential of neuronal pentraxin 2 as a biomarker in neurological disorders: A literature review

Neuronal pentraxin 2 (NP2) plays a significant role in synaptic plasticity, neuronal survival, and excitatory synapse regulation. Emerging research suggests that NP2 is implicated in the pathogenesis of various neurological disorders, including neurodegenerative diseases, neuropsychiatric disorders, and neuropathies. This literature review extensively analyzes NP2's role in these conditions, thereby highlighting its contributions to synaptic dysfunction, neuroinflammation, and neurotoxic protein aggregation. In Alzheimer's and Parkinson's diseases, NP2 is linked to amyloid-beta aggregation and dopaminergic neuron degeneration, respectively. Additionally, altered NP2 expression is observed in schizophrenia and bipolar disorder, thus suggesting its involvement in synaptic dysfunction and neurotransmitter imbalance. In neuropathic pain and epilepsy, NP2 modulates the synaptic plasticity and inflammatory responses, with altered levels correlating with disease severity. Furthermore, NP2's involvement in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) emphasizes its broad impact on neuronal health. Understanding NP2's multifaceted roles may reveal novel therapeutic targets and improve the clinical outcomes for these neurological disorders. Though the precise role of NP2 remains uncertain, its clinical potential and initial findings justify further investigations into neuronal pentraxins and other related neuroproteins.

APOE 𝜀4-related blood-brain barrier breakdown is associated with microstructural abnormalities

INTRODUCTION

Blood-brain barrier (BBB) dysfunction occurs in Alzheimer's disease (AD). Yet, the stage at which it appears along the AD time course and whether it contributes to neurodegeneration remain unclear.

METHODS

Older adults (61 to 90 years) from cognitively normal (CN) to mildly cognitively impaired (CI), enriched for APOE 𝜀4 and amyloid positivity, underwent dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and diffusion MRI to measure BBB permeability and brain microstructure. Analysis of variance compared BBB permeability according to cognitive status, amyloid beta (Aβ), and APOE4. Linear regressions assessed associations of BBB permeability with brain microstructure and interactions with Aβ and APOE4.

RESULTS

BBB permeability was elevated for APOE4 carriers across the cortical gray matter, with the strongest differences among CN amyloid-negative individuals. Associations between entorhinal BBB permeability and microstructure interacted with Aβ and APOE4, with the strongest relationships in amyloid-positive individuals and APOE4 carriers.

DISCUSSION

APOE4 may drive widespread BBB dysfunction in preclinical AD, which may contribute to neurodegenerative changes early along the AD cascade.

HIGHLIGHTS

Gray matter blood-brain barrier (BBB) permeability is elevated for APOE4 carriers. APOE4-related BBB breakdown appears in the absence of cognitive decline or amyloid. BBB leakage correlates with entorhinal cortex microstructural injury. Associations with microstructure are strongest for amyloid-positive APOE4 carriers.

Mediation Analysis with Multiple Exposures and Multiple Mediators

A mediation analysis approach is proposed for multiple exposures, multiple mediators, and a continuous scalar outcome under the linear structural equation modeling framework. It assumes that there exist orthogonal components that demonstrate parallel mediation mechanisms on the outcome, and thus is named principal component mediation analysis (PCMA). Likelihood-based estimators are introduced for simultaneous estimation of the component projections and effect parameters. The asymptotic distribution of the estimators is derived for low-dimensional data. A bootstrap procedure is introduced for inference. Simulation studies illustrate the superior performance of the proposed approach. Applied to a proteomics-imaging dataset from the Alzheimer's disease neuroimaging initiative (ADNI), the proposed framework identifies protein deposition - brain atrophy - memory deficit mechanisms consistent with existing knowledge and suggests potential AD pathology by integrating data collected from different modalities.

Neonatal hypoxia-ischemia alters the events governing the hippocampal critical period of postnatal synaptic plasticity leading to deficits in working memory in mice

Postnatal critical periods of synaptic plasticity (CPsp) are characterized by profound neural network refinement, which is shaped by synaptic activity and sculpted by maturation of the GABAergic network. Even after therapeutic hypothermia (TH), neonatal hypoxia-ischemia (HI) impairs two triggers for the initiation of the CPsp in the hippocampus: i) PSA-NCAM developmental decline and ii) parvalbumin (PV) + interneuron (IN) maturation. Thus, we investigated whether neonatal HI despite TH disturbs other events governing the onset, consolidation and closure of the postnatal CPsp in the hippocampus. We induced cerebral HI in P10 C57BL6 mice with right carotid ligation and 45 m of hypoxia (FiO2 = 0.08), followed by normothermia (36 °C, NT) or TH (31 °C) for 4 h with anesthesia-exposed shams as controls. ELISA, immunoblotting and immunohistochemistry were performed at 24 h (P11), 5 days (P15), 8 days (P18) and 30 days (P40) after HI injury. We specifically assessed: i) BDNF levels and TrkB activation, controlling the CPsp, ii) Otx2 and NPTX2 immunoreactivity (IR), engaging CPsp onset and iii) NogoR1, Lynx1 IR, PNN formation and myelination (MBP) mediating CPsp closure. Pups aged to P40 also received a battery of tests assessing working memory. Here, we documented deficits in hippocampal BDNF levels and TrkB activation at P18 in response to neonatal HI even with TH. Neonatal HI impaired in the CA1 the developmental increase in PV, Otx2, and NPTX2 between P11 and P18, the colocalization of Otx2 and PV at P18 and P40, the accumulation of NPTX2 in PV+ dendrites at P18 and P40, and the expression of NogoR at P40. Furthermore, neonatal HI decreased BDNF and impaired PNN development and myelination (MBP) at P40. Most of these abnormalities were insensitive to TH and correlated with memory deficits. Neonatal HI appears to disrupt many of the molecular and structural events initiating and consolidating the postnatal hippocampal CPsp, perhaps due to the early and delayed deficits in TrkB activation leading to memory deficits.

Biological mechanisms of resilience to tau pathology in Alzheimer's disease

BACKGROUND

In Alzheimer's disease (AD), the associations between tau pathology and brain atrophy and cognitive decline are well established, but imperfect. We investigate whether cerebrospinal fluid (CSF) biomarkers of biological processes (vascular, synaptic, and axonal integrity, neuroinflammation, neurotrophic factors) explain the disconnection between tau pathology and brain atrophy (brain resilience), and tau pathology and cognitive decline (cognitive resilience).

METHODS

We included 428 amyloid positive participants (134 cognitively unimpaired (CU), 128 with mild cognitive impairment (MCI), 166 with AD dementia) from the BioFINDER-2 study. At baseline, participants underwent tau positron emission tomography (tau-PET), magnetic resonance imaging (MRI), cognitive testing, and lumbar puncture. Longitudinal data were available for MRI (mean (standard deviation) follow-up 26.4 (10.7) months) and cognition (25.2 (11.4) months). We analysed 18 pre-selected CSF proteins, reflecting vascular, synaptic, and axonal integrity, neuroinflammation, and neurotrophic factors. Stratifying by cognitive status, we performed linear mixed-effects models with cortical thickness (brain resilience) and global cognition (cognitive resilience) as dependent variables to assess whether the CSF biomarkers interacted with tau-PET levels in its effect on cortical atrophy and cognitive decline.

RESULTS

Regarding brain resilience, interaction effects were observed in AD dementia, with vascular integrity biomarkers (VEGF-A (βinteraction = -0.009, pFDR = 0.047) and VEGF-B (βinteraction = -0.010, pFDR = 0.037)) negatively moderating the association between tau-PET signal and atrophy. In MCI, higher NfL levels were associated with more longitudinal cortical atrophy (β = -0.109, pFDR = 0.033) and lower baseline cortical thickness (β = -0.708, pFDR = 0.033) controlling for tau-PET signal. Cognitive resilience analyses in CU revealed interactions with tau-PET signal for inflammatory (GFAP, IL-15; βinteraction -0.073--0.069, pFDR 0.001-0.045), vascular (VEGF-A, VEGF-D, PGF; βinteraction -0.099--0.063, pFDR < 0.001-0.046), synaptic (14-3-3ζ/δ; βinteraction = -0.092, pFDR = 0.041), axonal (NfL; βinteraction = -0.079, pFDR < 0.001), and neurotrophic (NGF; βinteraction = 0.091, pFDR < 0.001) biomarkers. In MCI higher NfL levels (βmain = -0.690, pFDR = 0.025) were associated with faster cognitive decline independent of tau-PET signal.

CONCLUSIONS

Biomarkers of co-existing pathological processes, in particular vascular pathology and axonal degeneration, interact with levels of tau pathology on its association with the downstream effects of AD pathology (i.e. brain atrophy and cognitive decline). This indicates that vascular pathology and axonal degeneration could impact brain and cognitive resilience.

miR-133b as a potential regulator of a synaptic NPTX2 protein in Alzheimer's disease

A synaptic protein, Neuronal Pentraxin 2 (NPTX2), has emerged as a pivotal biomarker for Alzheimer's dementia (AD). We identified candidate miRNAs targeting NPTX2 and performed association and mediation analyses using multi-omics data (N = 702). Among 44 candidate miRNAs, miR-133b was significantly associated with AD and Braak positivity. Higher miR-133b expression was also associated with higher NPTX2 gene expression and better cognition. Mediation analysis showed that miR-133b partially influences AD and cognition through the NPTX2 protein. Our integrated approach suggests a potential role of miR-133b in synaptic integrity and offers new insights into AD pathogenesis.

Transcriptional Patterns in Stages of Alzheimer's Disease Are Cell-Type-Specific and Partially Converge with the Effects of Alcohol Use Disorder in Humans

Advances in single-cell technologies have led to the discovery and characterization of new brain cell types, which in turn lead to a better understanding of the pathogenesis of Alzheimer's disease (AD). Here, we present a detailed analysis of single-nucleus (sn)RNA-seq data for three stages of AD from middle temporal gyrus and compare it with snRNA-seq data from the prefrontal cortices from individuals with alcohol use disorder (AUD). We observed a significant decrease in both inhibitory and excitatory neurons, in general agreement with previous reports. We observed several cell-type-specific gene expressions and pathway dysregulations that delineate AD stages. Endothelial and vascular leptomeningeal cells showed the greatest degree of gene expression changes. Cell-type-specific evidence of neurodegeneration was seen in multiple neuronal cell types particularly in somatostatin and Layer 5 extratelencephalic neurons, among others. Evidence of inflammatory responses was seen in non-neuronal cells, particularly in intermediate and advanced AD. We observed common perturbations in AD and AUD, particularly in pathways, like transcription, translation, apoptosis, autophagy, calcium signaling, neuroinflammation, and phosphorylation, that imply shared transcriptional pathogenic mechanisms and support the role of excessive alcohol intake in AD progression. Major AUD gene markers form and perturb a network of genes significantly associated with intermediate and advanced AD. Master regulator analysis from AUD gene markers revealed significant correlation with advanced AD of transcription factors that have implications in intellectual disability, neuroinflammation, and other neurodegenerative conditions, further suggesting a shared nexus of transcriptional changes between AD and AUD.

Increased Inflammation as well as Decreased Endoplasmic Reticulum Stress and Translation Differentiate Pancreatic Islets of Pre-symptomatic Stage 1 Type 1 Diabetes and Non-diabetic Cases

Aims/hypothesis

Progression to type 1 diabetes (T1D) is associated with genetic factors, the presence of autoantibodies, and a decline in β cell insulin secretion in response to glucose. Very little is known regarding the molecular changes that occur in human insulin-secreting β-cells prior to the onset of T1D. Herein, we applied an unbiased proteomics approach to identify changes in proteins and potential mechanisms of islet dysfunction in islet autoantibody-positive organ donors with pre-symptomatic stage 1 T1D (HbA1c ≤ 6). We aimed to identify pathways in islets that are indicative of β-cell dysfunction.

Methods

Multiple islet sections were collected through laser microdissection of frozen pancreatic tissues of organ donors positive for islet autoantibodies (AAb+, n=5), compared to age/sex-matched nondiabetic controls (ND, n=5) obtained from the Network for Pancreatic Organ donors with Diabetes (nPOD). Islet sections were subjected to mass spectrometry-based proteomics and analyzed with label-free quantification followed by pathway and functional annotations.

Results

Analyses resulted in ~4,500 proteins identified with low false discovery rate (FDR) <1%, with 2,165 proteins reliably quantified in every islet sample. We observed large inter-donor variations that presented a challenge for statistical analysis of proteome changes between donor groups. We therefore focused on the three multiple AAb+ cases (mAAb+) with high genetic risk and their three matched controls for a final statistical analysis. Approximately 10% of the proteins (n=202) were significantly different between mAAb+ cases versus ND. The significant alterations clustered around major functions for upregulation in the immune response and glycolysis, and downregulation in endoplasmic reticulum (ER) stress response as well as protein translation and synthesis. The observed proteome changes were further supported by several independent published datasets, including proteomics dataset from in vitro proinflammatory cytokine-treated human islets and single cell RNA-seq data sets from AAb+ cases.

Conclusion/interpretation

In-situ human islet proteome alterations at the stage 1 of AAb+ T1D centered around several major functional categories, including an expected increase in immune response genes (elevated antigen presentation / HLA), with decreases in protein synthesis and ER stress response, as well as compensatory metabolic response. The dataset serves as a proteomics resource for future studies on β cell changes during T1D progression and pathogenesis.

Network proteomics of the Lewy body dementia brain reveals presynaptic signatures distinct from Alzheimer's disease

Lewy body dementia (LBD), a class of disorders comprising Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB), features substantial clinical and pathological overlap with Alzheimer's disease (AD). The identification of biomarkers unique to LBD pathophysiology could meaningfully advance its diagnosis, monitoring, and treatment. Using quantitative mass spectrometry (MS), we measured over 9,000 proteins across 138 dorsolateral prefrontal cortex (DLPFC) tissues from a University of Pennsylvania autopsy collection comprising control, Parkinson's disease (PD), PDD, and DLB diagnoses. We then analyzed co-expression network protein alterations in those with LBD, validated these disease signatures in two independent LBD datasets, and compared these findings to those observed in network analyses of AD cases. The LBD network revealed numerous groups or "modules" of co-expressed proteins significantly altered in PDD and DLB, representing synaptic, metabolic, and inflammatory pathophysiology. A comparison of validated LBD signatures to those of AD identified distinct differences between the two diseases. Notably, synuclein-associated presynaptic modules were elevated in LBD but decreased in AD relative to controls. We also found that glial-associated matrisome signatures consistently elevated in AD were more variably altered in LBD, ultimately stratifying those LBD cases with low versus high burdens of concurrent beta-amyloid deposition. In conclusion, unbiased network proteomic analysis revealed diverse pathophysiological changes in the LBD frontal cortex distinct from alterations in AD. These results highlight the LBD brain network proteome as a promising source of biomarkers that could enhance clinical recognition and management.

Identification and experimental validation of m7G-related molecular subtypes, immune signature, and feature genes in Alzheimer's disease

Background

Studies has shown that N7-methylguanosine (m7G) modification plays a critical role in neurological diseases. However, the exact role and association of m7G with the immune microenvironment in Alzheimer's disease (AD) remain largely unknown and unexplored.

Methods

The study datasets comprised 667 AD samples and 503 control samples selected from eight datasets in the Gene Expression Omnibus database; m7G regulator genes were obtained from previous literature. The AD subtypes were identified by consensus clustering analysis according to m7G regulator genes. The clinical characteristics, immune infiltration, and biological functions of the AD subgroups were evaluated. A combination of different types of machine-learning algorithms were used for the identification of AD genes. We also assessed and validated the diagnostic performance of the identified genes via qRT-PCR, immunofluorescence, and immunohistochemical analyses.

Results

Two AD distinct subgroups, namely cluster A and cluster B, were identified. Cluster A had poor pathological progression and immune infiltration, representing a high-risk subgroup for AD. The differentially expressed genes of cluster A were enriched in immune and synapse-related pathways, suggesting that these genes probably contribute to AD progression by regulating immune-related pathways. Additionally, five feature genes (AEBP1, CARTPT, AK5, NPTX2, and COPG2IT1) were identified, which were used to construct a nomogram model with good ability to predict AD. The animal experiment analyses further confirmed that these feature genes were associated with AD development.

Conclusion

To the best of our knowledge, this is the first study to reveal close correlations among m7G RNA modification, the immune microenvironment, and the pathogenesis of AD. We also identified five feature genes associated with AD, further contributing to our understanding of the underlying mechanisms and potential therapeutic targets for AD.

Cerebrospinal fluid biomarker panel for synaptic dysfunction in a broad spectrum of neurodegenerative diseases

Synaptic dysfunction and degeneration is likely the key pathophysiology for the progression of cognitive decline in various dementia disorders. Synaptic status can be monitored by measuring synaptic proteins in CSF. In this study, both known and new synaptic proteins were investigated and compared as potential biomarkers of synaptic dysfunction, particularly in the context of Alzheimer's disease (AD). Seventeen synaptic proteins were quantified in CSF using two different targeted mass spectrometry assays in the prospective Swedish BioFINDER-2 study. The study included 958 individuals, characterized as having mild cognitive impairment (MCI, n = 205), AD dementia (n = 149) and a spectrum of other neurodegenerative diseases (n = 171), in addition to cognitively unimpaired individuals (CU, n = 443). Synaptic protein levels were compared between diagnostic groups and their associations with cognitive decline and key neuroimaging measures (amyloid-β-PET, tau-PET and cortical thickness) were assessed. Among the 17 synaptic proteins examined, 14 were specifically elevated in the AD continuum. SNAP-25, 14-3-3 zeta/delta, β-synuclein, and neurogranin exhibited the highest discriminatory accuracy in differentiating AD dementia from controls (areas under the curve = 0.81-0.93). SNAP-25 and 14-3-3 zeta/delta also had the strongest associations with tau-PET, amyloid-β-PET and cortical thickness at baseline and were associated with longitudinal changes in these imaging biomarkers [β(standard error, SE) = -0.056(0.0006) to 0.058(0.005), P < 0.0001]. SNAP-25 was the strongest predictor of progression to AD dementia in non-demented individuals (hazard ratio = 2.11). In contrast, neuronal pentraxins were decreased in all neurodegenerative diseases (except for Parkinson's disease), and NPTX2 showed the strongest associations with subsequent cognitive decline [longitudinal Mini-Mental State Examination: β(SE) = 0.57(0.1), P ≤ 0.0001; and mPACC: β(SE) = 0.095(0.024), P ≤ 0.001] across the AD continuum. Interestingly, utilizing a ratio of the proteins that displayed higher levels in AD, such as SNAP-25 or 14-3-3 zeta/delta, over NPTX2 improved the biomarkers' associations with cognitive decline and brain atrophy. We found 14-3-3 zeta/delta and SNAP-25 to be especially promising as synaptic biomarkers of pathophysiological changes in AD. Neuronal pentraxins were identified as general indicators of neurodegeneration and associated with cognitive decline across various neurodegenerative dementias. Cognitive decline and brain atrophy were best predicted by ratios of SNAP-25/NPTX2 and 14-3-3 zeta/delta/NPTX2.

Parvalbumin interneuron cell-to-network plasticity: mechanisms and therapeutic avenues

Alzheimer's disease (AD) and schizophrenia (SCZ) represent two major neuropathological conditions with a high disease burden. Despite their distinct etiologies, patients suffering from AD or SCZ share a common burden of disrupted memory functions unattended by current therapies. Recent preclinical analyses highlight cell-type-specific contributions of parvalbumin interneurons (PVIs), particularly the plasticity of their cellular excitability, towards intact neuronal network function (cell-to-network plasticity) and memory performance. Here we argue that deficits of PVI cell-to-network plasticity may underlie memory deficits in AD and SCZ, and we explore two therapeutic avenues: the targeting of PVI-specific neuromodulation, including by neuropeptides, and the recruitment of network synchrony in the gamma frequency range (40 Hz) by external stimulation. We finally propose that these approaches be merged under consideration of recent insights into human brain physiology.

NARP-related alterations in the excitatory and inhibitory circuitry of socially isolated mice: developmental insights and implications for autism spectrum disorder

Background

Social isolation during critical periods of development is associated with alterations in behavior and neuronal circuitry. This study aimed to investigate the immediate and developmental effects of social isolation on firing properties, neuronal activity-regulated pentraxin (NARP) and parvalbumin (PV) expression in the prefrontal cortex (PFC), social behavior in juvenile socially isolated mice, and the biological relevance of NARP expression in autism spectrum disorder (ASD).

Methods

Mice were subjected to social isolation during postnatal days 21-35 (P21-P35) and were compared with group-housed control mice. Firing properties in the PFC pyramidal neurons were altered in P35 socially isolated mice, which might be associated with alterations in NARP and PV expression.

Results

In adulthood, mice that underwent juvenile social isolation exhibited difficulty distinguishing between novel and familiar mice during a social memory task, while maintaining similar levels of social interaction as the control mice. Furthermore, a marked decrease in NARP expression in lymphoblastoid cell lines derived from adolescent humans with ASD as compared to typically developing (TD) humans was found.

Conclusion

Our study highlights the role of electrophysiological properties, as well as NARP and PV expression in the PFC in mediating the developmental consequences of social isolation on behavior.

Potential prognostic value of CSF-targeted proteomics across the Alzheimer's disease continuum

BACKGROUND

Core biomarkers for Alzheimer's disease (AD), such as Aβ42 and tau, have demonstrated high prognostic accuracy but do not fully capture the complex pathophysiology of AD. In this study, our objective was to identify novel cerebrospinal fluid (CSF) biomarkers using proteomics across the entire AD continuum to predict conversion to AD and explore their involvement in AD pathogenesis.

METHODS

A cohort of 186 cognitively normal (CN), 127 subjective memory complaint (SMC), 79 early mild cognitive impairment (EMCI), 249 late MCI (LMCI), and 132 AD individuals was analyzed, with a follow-up period of over 3 years for non-AD participants. CSF 65 peptides, as well as hippocampal and entorhinal volumes were analyzed, and cognitive function was evaluated using the 13-item cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-Cog 13). Cox proportional hazards models and mediation analysis were performed to investigate associations and causal relationships.

RESULTS

During the follow-up, approximately one-fourth (146/580) of the non-AD participants progressed to AD. After adjusting for baseline diagnosis (CN to LMCI) and other variables, multivariable Cox regression analysis identified three peptides (VAELEDEK, VSFELFADK, and VVSSIEQK) as significant predictors of conversion to AD. Incorporating these three peptides into the initial model significantly improved the C-statistic from 0.82 to 0.85 for predicting AD conversion, surpassing the predictive ability of Aβ42 and P-tau. Moreover, hippocampal and entorhinal volumes mediated 30.3-53.8% of the association between the three peptides and ADAS-Cog 13 scores.

CONCLUSIONS

These findings underscore the potential of these three peptides as robust prognostic biomarker candidates for AD conversion across the entire AD continuum, with a mechanism involving the mediation of hippocampal and entorhinal volumes.

Mechanisms and implications of gamma oscillation plasticity

A recent study by Hadler and colleagues uncovered a novel form of plasticity of gamma oscillations in an ex vivo hippocampal slice preparation which they term 'gamma potentiation'. We discuss the potential cellular mechanisms of this form of plasticity and its functional and translational implications.

Serum NPTX2 as a Potential Predictive Biomarker for Postoperative Delirium in Patients with Acute Type A Aortic Dissection

Background

Postoperative delirium (POD) significantly impacts patient outcomes after acute type A aortic dissection (ATAAD) surgeries. This study investigates the role of Neuronal Pentraxin 2 (NPTX2) as a potential biomarker for POD in ATAAD patients.

Methods

This secondary analysis involved ATAAD patients from a prospective observational study. Serum NPTX2 levels were measured preoperatively and immediately postoperatively using Enzyme-Linked Immunosorbent Assay (ELISA). Delirium was assessed using the Confusion Assessment Method (CAM) or CAM for the ICU (CAM-ICU). Statistical analyses included the Pearson Correlation Coefficient and multivariate logistic regression to evaluate the association between NPTX2 levels and POD.

Results

Among the 62 patients included, 46.77% developed POD. Patients with POD had significantly lower preoperative and postoperative serum NPTX2 levels. The Receiver Operating Characteristic (ROC) curve analysis showed that postoperative NPTX2 had a strong predictive capability for POD (AUC = 0.895). The optimal cutoff for postoperative NPTX2 in predicting POD was less than 421.4 pg/mL. Preoperative NPTX2 also demonstrated predictive value, albeit weaker (AUC = 0.683).

Conclusion

Serum NPTX2 levels, both preoperatively and postoperatively, are promising biomarkers for predicting POD in ATAAD patients. These findings suggest that NPTX2 could be instrumental in early POD detection and intervention strategies.

Biofluid biomarkers for Alzheimer's disease

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease, with a complex pathogenesis and an irreversible course. Therefore, the early diagnosis of AD is particularly important for the intervention, prevention, and treatment of the disease. Based on the different pathophysiological mechanisms of AD, the research progress of biofluid biomarkers are classified and reviewed. In the end, the challenges and perspectives of future research are proposed.

Glycoproteome-Wide Discovery of Cortical Glycoproteins That May Provide Cognitive Resilience in Older Adults

BACKGROUND AND OBJECTIVES

Molecular omics studies have identified proteins related to cognitive resilience but unrelated to Alzheimer disease and Alzheimer disease-related dementia (AD/ADRD) pathologies. Posttranslational modifications of proteins with glycans can modify protein function. In this study, we identified glycopeptiforms associated with cognitive resilience.

METHODS

We studied brains from adults with annual cognitive testing with postmortem indices of 10 AD/ADRD pathologies and proteome-wide data from dorsal lateral prefrontal cortex (DLPFC). We quantified 11, 012 glycopeptiforms from DLPFC using liquid chromatography with tandem mass spectrometry. We used linear mixed-effects models to identify glycopeptiforms associated with cognitive decline correcting for multiple comparisons (p < 5 × 10-6). Then, we regressed out the effect of AD/ADRD pathologies to identify glycopeptiforms that may provide cognitive resilience.

RESULTS

We studied 366 brains, average age at death 89 years, and 70% female with no cognitive impairment = 152, mild cognitive impairment = 93, and AD = 121 cognitive status at death. In models adjusting for age, sex and education, 11 glycopeptiforms were associated with cognitive decline. In further modeling, 8 of these glycopeptiforms remained associated with cognitive decline after adjusting for AD/ADRD pathologies: NPTX2a (Est., 0.030, SE, 0.005, p = 1 × 10-4); NPTX2b (Est.,0.019, SE, 0.005, p = 2 × 10-4) NECTIN1(Est., 0.029, SE, 0.009, p = 9 × 10-4), NPTX2c (Est., 0.015, SE, 0.004, p = 9 × 10-4), HSPB1 (Est., -0.021, SE, 0.006, p = 2 × 10-4), PLTP (Est., -0.027, SE, 0.009, p = 4.2 × 10-3), NAGK (Est., -0.027, SE, 0.008, p = 1.4 × 10-3), and VAT1 (Est., -0.020, SE, 0.006, p = 1.1 × 10-3). Higher levels of 4 resilience glycopeptiforms derived through glycosylation were associated with slower decline and higher levels of 4 derived through glycation were related to faster decline. Together, these 8 glycopeptiforms accounted for an additional 6% of cognitive decline over the 33% accounted for the 10 brain pathologies and demographics. All 8 resilience glycopeptiforms remained associated with cognitive decline after adjustments for the expression level of their corresponding protein. Exploratory gene ontology suggested that molecular mechanisms of glycopeptiforms associated with cognitive decline may involve metabolic pathways including pyruvate and NADH pathways and highlighted the importance of molecular mechanisms involved in glucose metabolism.

DISCUSSION

Glycopeptiforms in aging brains may provide cognitive resilience. Targeting these glycopeptiforms may lead to therapies that maintain cognition through resilience.

Cerebrospinal fluid NPTX2 changes and relationship with regional brain metabolism metrics across mild cognitive impairment due to Alzheimer's disease

BACKGROUND

Neuronal pentraxin-2 (NPTX2), crucial for synaptic functioning, declines in cerebrospinal fluid (CSF) as cognition deteriorates. The variations of CSF NPTX2 across mild cognitive impairment (MCI) due to Alzheimer's disease (AD) and its association with brain metabolism remain elusive, albeit relevant for patient stratification and pathophysiological insights.

METHODS

We retrospectively analyzed 49 MCI-AD patients grouped by time until dementia (EMCI, n = 34 progressing within 2 years; LMCI, n = 15 progressing later/stable at follow-up). We analyzed demographic variables, cognitive status (MMSE score), and CSF NPTX2 levels using a commercial ELISA assay in EMCI, LMCI, and a control group of age-/sex-matched individuals with other non-dementing disorders (OND). Using [18F]FDG PET scans for voxel-based analysis, we explored correlations between regional brain metabolism metrics and CSF NPTX2 levels in MCI-AD patients, accounting for age.

RESULTS

Baseline and follow-up MMSE scores were lower in LMCI than EMCI (p value = 0.006 and p < 0.001). EMCI exhibited significantly higher CSF NPTX2 values than both LMCI (p = 0.028) and OND (p = 0.006). We found a significant positive correlation between NPTX2 values and metabolism of bilateral precuneus in MCI-AD patients (p < 0.005 at voxel level, p < 0.05 with family-wise error correction at the cluster level).

CONCLUSIONS

Higher CSF NPTX2 in EMCI compared to controls and LMCI suggests compensatory synaptic responses to initial AD pathology. Disease progression sees these mechanisms overwhelmed, lowering CSF NPTX2 approaching dementia. Positive CSF NPTX2 correlation with precuneus glucose metabolism links to AD-related metabolic changes across MCI course. These findings posit CSF NPTX2 as a promising biomarker for both AD staging and progression risk stratification.

Levels of neuronal pentraxin 2 in plasma is associated with cognitive function in patients with schizophrenia

RATIONALE

The precise diagnosis and treatment of cognitive impairment remains a major challenge in the field of schizophrenia (SCZ) research. Synaptic dysfunction and loss are thought to be closely related to the occurrence and development of SCZ and may be involved in cognitive dysfunction.

OBJECTIVES

The purpose of this study was to investigate whether neuronal pentraxins (NPTXs) plays a role in the etiology of SCZ and provide evidence of its possible therapeutic value a new target for drug development.

METHODS

We recruited 275 participants, of whom 148 were SCZ from psychiatric hospital and 127 healthy control (HC) subjects from communities. Plasma concentrations of NPTXs were measured in HC and SCZ at baseline and after 8 weeks of antipsychotic treatment. The MATRICS Cognitive Consensus Battery was used to evaluate cognitive function. Furthermore, the brain is parcellated into 246 subregions using the Brainnetome atlas, and we extracted regional white matter volumes from magnetic resonance images of the SCZ groups.

RESULTS

Plasma NPTX2 levels were significantly lower in SCZ compared with HC subjects, but were significantly raised in SCZ after 8 weeks of antipsychotic treatment compared to baseline. In addition, baseline plasma NPTX2 levels were positively correlated with cognitive performance.

CONCLUSIONS

These findings indicate that NPTX2 may reveal novel aspects of disease etiology and act as a promising target for new drug development.

Serum NFL and tau, but not serum UCHL-1 and GFAP or CSF SNAP-25, NPTX2, or sTREM2, correlate with delirium in a 3-year retrospective analysis

Delirium represents a common terminal pathway of heterogeneous neurological conditions characterized by disturbances in consciousness and attention. Contemporary theories highlight the acute impairment of synaptic function and network connectivity, driven by neuroinflammation, oxidative stress, and neurotransmitter imbalances. However, established biomarkers are still missing. Innovative diagnostic techniques, such as single-molecule array analysis, enable the detection of biomarkers in blood at picomolar concentrations. This approach paves the way for deeper insights into delirium and potentially therapeutic targets for tailored medical treatments. In a retrospective 3-year study, we investigated seven biomarkers indicative of neuroaxonal damage [neurofilament light chain (NFL), ubiquitin carboxyl-terminal hydrolase (UCHL-1), and tau protein], microglial activation [glial fibrillary acidic protein (GFAP) and soluble triggering receptor expressed on myeloid cells 2 (sTREM2)], and synaptic dysfunction [synaptosomal-associated protein 25 (SNAP-25) and neuronal pentraxin 2 (NPTX2)]. The analysis of 71 patients with delirium, Alzheimer's disease (AD), and non-AD controls revealed that serum NFL levels are higher in delirium cases compared to both AD and non-AD. This suggests that elevated NFL levels in delirium are not exclusively the result of dementia-related damage. Serum tau levels were also elevated in delirium cases compared to controls. Conversely, cerebrospinal fluid (CSF) SNAP-25 showed higher levels in AD patients compared to controls only. These findings add to the increasing body of evidence suggesting that serum NFL could be a valuable biomarker of neuroaxonal damage in delirium research. Although SNAP-25 and NPTX2 did not exhibit significant differences in delirium, the exploration of synaptic biomarkers remains promising for enhancing our understanding of this condition.

Monitoring synaptic pathology in Alzheimer's disease through fluid and PET imaging biomarkers: a comprehensive review and future perspectives

Alzheimer's disease (AD) is currently constrained by limited clinical treatment options. The initial pathophysiological event, which can be traced back to decades before the clinical symptoms become apparent, involves the excessive accumulation of amyloid-beta (Aβ), a peptide comprised of 40-42 amino acids, in extraneuronal plaques within the brain. Biochemical and histological studies have shown that overaccumulation of Aβ instigates an aberrant escalation in the phosphorylation and secretion of tau, a microtubule-binding axonal protein. The accumulation of hyperphosphorylated tau into intraneuronal neurofibrillary tangles is in turn correlated with microglial dysfunction and reactive astrocytosis, culminating in synaptic dysfunction and neurodegeneration. As neurodegeneration progresses, it gives rise to mild clinical symptoms of AD, which may eventually evolve into overt dementia. Synaptic loss in AD may develop even before tau alteration and in response to possible elevations in soluble oligomeric forms of Aβ associated with early AD. These findings largely rely on post-mortem autopsy examinations, which typically involve a limited number of patients. Over the past decade, a range of fluid biomarkers such as neurogranin, α-synuclein, visinin-like protein 1 (VILIP-1), neuronal pentraxin 2, and β-synuclein, along with positron emission tomography (PET) markers like synaptic vesicle glycoprotein 2A, have been developed. These advancements have facilitated the exploration of how synaptic markers in AD patients correlate with cognitive impairment. However, fluid biomarkers indicating synaptic loss have only been validated in cerebrospinal fluid (CSF), not in plasma, with the exception of VILIP-1. The most promising PET radiotracer, [11C]UCB-J, currently faces significant challenges hindering its widespread clinical use, primarily due to the necessity of a cyclotron. As such, additional research geared toward the exploration of synaptic pathology biomarkers is crucial. This will not only enable their extensive clinical application, but also refine the optimization process of AD pharmacological trials.

General and specific patterns of cortical gene expression as spatial correlates of complex cognitive functioning

Gene expression varies across the brain. This spatial patterning denotes specialised support for particular brain functions. However, the way that a given gene's expression fluctuates across the brain may be governed by general rules. Quantifying patterns of spatial covariation across genes would offer insights into the molecular characteristics of brain areas supporting, for example, complex cognitive functions. Here, we use principal component analysis to separate general and unique gene regulatory associations with cortical substrates of cognition. We find that the region-to-region variation in cortical expression profiles of 8235 genes covaries across two major principal components: gene ontology analysis suggests these dimensions are characterised by downregulation and upregulation of cell-signalling/modification and transcription factors. We validate these patterns out-of-sample and across different data processing choices. Brain regions more strongly implicated in general cognitive functioning (g; 3 cohorts, total meta-analytic N = 39,519) tend to be more balanced between downregulation and upregulation of both major components (indicated by regional component scores). We then identify a further 29 genes as candidate cortical spatial correlates of g, beyond the patterning of the two major components (|β| range = 0.18 to 0.53). Many of these genes have been previously associated with clinical neurodegenerative and psychiatric disorders, or with other health-related phenotypes. The results provide insights into the cortical organisation of gene expression and its association with individual differences in cognitive functioning.

Association of reduced cerebrospinal fluid NPTX2 levels with postoperative delirium in patients undergoing knee/hip replacement: a prospective cohort study

BACKGROUND

Postoperative delirium (POD) is a common complication with poor prognosis in the elderly, but its mechanism has not been fully elucidated. There is evidence that the changes in synaptic activity in the brain are closely related to the occurrence of POD. And neuronal pentraxin 2 (NPTX2) can regulate synaptic activity in vivo.

AIMS

This study aims to explore whether decreased NPTX2 levels affects POD and whether the cerebrospinal fluid (CSF) biomarkers of POD mediate this association.

METHODS

In this prospective cohort study, we interviewed patients with knee/hip replacement 1 day before surgery to collect patient information and assess their cognitive function. CSF was extracted for measuring the CSF levels of NPTX2 and other POD biomarkers on the day of surgery. And postoperative follow-up visits were performed 1-7 days after surgery.

RESULTS

Finally, 560 patients were included in the study. The patients were divided into POD group and NPOD (non-POD) group. The POD group had a median age of 80 years, a female proportion of 45%, a median BMI of 24.1 kg/m2, and a median years of education of 9 years. The Mann-Whitney U test showed that CSF NPTX2 levels were significantly lower in POD group, compared with the NPOD group (P < 0.05). Univariate binary logistic regression analysis showed that reduced CSF levels of NPTX2 protected against POD (crude OR = 0.994, 95% CI 0.993-0.995, P < 0.001). The receiver-operating characteristic (ROC) curve indicated that CSF NPTX2 level had high predictive value for POD. Mediation analyses showed that CSF T-tau (mediating proportion = 21%) and P-tau (mediating proportion = 29%) had significant mediating effects on the association between CSF NPTX2 and POD.

CONCLUSION

CSF NPTX2 levels were associated with the occurrence of POD. Low CSF NPTX2 levels may be an independent protective factor for POD. CSF T-tau and P-tau could mediate the association between CSF NPTX2 and POD occurrence.

CLINICAL TRIAL REGISTRATION

The trial registration number (TRN): ChiCTR2200064740, Date of Registration: 2022-10-15.

Genomic analysis in the colon tissues of omega-3 fatty acid-treated rats identifies novel gene signatures implicated in ulcerative colitis

Several long-term intervention trials only studied the ex vivo immunological function to elucidate the beneficial mechanisms of n-3 polyunsaturated fatty acids (PUFA) in the ulcerative colitis (UC). An unbiased whole-transcriptome analysis would be more valuable to obtain a comprehensive understanding of the processes and genes regulated by n-3 PUFA in vivo. In this study, we have performed microarray analysis in the colon tissues of dextran sulfate sodium (DSS)-induced UC in rats supplemented with n-6 PUFA, n-3PUFA and long-chain n-3PUFA (LC-n3PUFA). We have identified the novel gene signatures previously not linked to colitis such as Etv3, Clec4d, CD180, CD72, Megf11, and Angptl4 which are most downregulated in both n-3PUFA and LC-n3PUFA groups compared to the n-6PUFA group. The most upregulated genes were Nr1i3, Nptx2, and Zfp810 in both n-3PUFA and LC-n3PUFA groups. The RT-PCR analysis confirmed similar results. Interestingly, LPS treatment in macrophages upregulated the Megf11, Etv3, CD180, and Angptl4, and correlated with increased secretion of cytokines. Gene silencing of Etv3, Megf11, and CD180 in rats using intravascular delivery of siRNA-lipoparticles attenuated the DSS-induced ulceration and mucosal damage. Thus, our genome-wide microarray analysis identified novel genes regulated by omega-3 PUFA and offers new drug targets that could prevent or reduce UC.

A model of human neural networks reveals NPTX2 pathology in ALS and FTLD

Human cellular models of neurodegeneration require reproducibility and longevity, which is necessary for simulating age-dependent diseases. Such systems are particularly needed for TDP-43 proteinopathies1, which involve human-specific mechanisms2-5 that cannot be directly studied in animal models. Here, to explore the emergence and consequences of TDP-43 pathologies, we generated induced pluripotent stem cell-derived, colony morphology neural stem cells (iCoMoNSCs) via manual selection of neural precursors6. Single-cell transcriptomics and comparison to independent neural stem cells7 showed that iCoMoNSCs are uniquely homogenous and self-renewing. Differentiated iCoMoNSCs formed a self-organized multicellular system consisting of synaptically connected and electrophysiologically active neurons, which matured into long-lived functional networks (which we designate iNets). Neuronal and glial maturation in iNets was similar to that of cortical organoids8. Overexpression of wild-type TDP-43 in a minority of neurons within iNets led to progressive fragmentation and aggregation of the protein, resulting in a partial loss of function and neurotoxicity. Single-cell transcriptomics revealed a novel set of misregulated RNA targets in TDP-43-overexpressing neurons and in patients with TDP-43 proteinopathies exhibiting a loss of nuclear TDP-43. The strongest misregulated target encoded the synaptic protein NPTX2, the levels of which are controlled by TDP-43 binding on its 3' untranslated region. When NPTX2 was overexpressed in iNets, it exhibited neurotoxicity, whereas correcting NPTX2 misregulation partially rescued neurons from TDP-43-induced neurodegeneration. Notably, NPTX2 was consistently misaccumulated in neurons from patients with amyotrophic lateral sclerosis and frontotemporal lobar degeneration with TDP-43 pathology. Our work directly links TDP-43 misregulation and NPTX2 accumulation, thereby revealing a TDP-43-dependent pathway of neurotoxicity.

Targeting synapse function and loss for treatment of neurodegenerative diseases

Synapse dysfunction and loss are hallmarks of neurodegenerative diseases that correlate with cognitive decline. However, the mechanisms and therapeutic strategies to prevent or reverse synaptic damage remain elusive. In this Review, we discuss recent advances in understanding the molecular and cellular pathways that impair synapses in neurodegenerative diseases, including the effects of protein aggregation and neuroinflammation. We also highlight emerging therapeutic approaches that aim to restore synaptic function and integrity, such as enhancing synaptic plasticity, preventing synaptotoxicity, modulating neuronal network activity and targeting immune signalling. We discuss the preclinical and clinical evidence for each strategy, as well as the challenges and opportunities for developing effective synapse-targeting therapeutics for neurodegenerative diseases.

Serial Cerebrospinal Fluid Sampling Reveals Trajectories of Potential Synaptic Biomarkers in Early Stages of Alzheimer's Disease

Background

Synaptic dysfunction is closely associated with cognitive function in Alzheimer's disease (AD), and is present already in an early stage of the disease.

Objective

Using serial cerebrospinal fluid (CSF) sampling, we aimed to investigate slopes of CSF synaptic proteins, and their relation with cognition along the AD continuum.

Methods

We included subjects with subjective cognitive decline (SCD) or mild cognitive impairment (MCI) (n = 50 amyloid-β+ [A +], n = 50 A-) and 50 patients with AD dementia from the Amsterdam dementia cohort, with CSF at two time points (median[IQR] 2.1[1.4-2.7] years). We analyzed 17 synaptic proteins and neurofilament light (NfL). Using linear mixed models we assessed trajectories of protein levels, and associations with cognitive decline (repeated Mini-Mental State Examination). We used Cox regression models to assess predictive value of protein levels for progression to AD dementia.

Results

At baseline most proteins showed increased levels in AD dementia compared to the other groups. In contrast NPTX2 levels were lower in AD dementia. Higher baseline levels of SNAP25, β-syn, and 14-3-3 proteins were associated with faster cognitive decline (St.B[SE] -0.27[0.12] to -0.61[0.12]). Longitudinal analyses showed that SYT1 and NPTX levels decreased over time in AD dementia (st.B[SE] -0.10[0.04] to -0.15[0.05]) and SCD/MCI-A+ (St.B[SE] -0.07[0.03] to -0.12[0.03]), but not in SCD/MCI-A- (pinteraction < 0.05). Increase over time in NfL levels was associated with faster cognitive decline in AD dementia (St.B[SE] -1.75[0.58]), but not in the other groups (pinteraction < 0.05).

Conclusions

CSF synaptic proteins showed different slopes over time, suggesting complex synaptic dynamics. High levels of especially SNAP-25 may have value for prediction of cognitive decline in early AD stages, while increase in NfL over time correlates better with cognitive decline in later stages.

The MINT Sprint 2.0: A picture naming test for detection of naming impairments in Alzheimer's disease and in preclinical AD

INTRODUCTION

Evidence on the onset of naming deficits in Alzheimer's disease (AD) is mixed. Some studies showed an early decline, but others did not. The present study introduces evidence from a novel naming test.

METHODS

Cognitively normal (n = 138), mild cognitive impairment (MCI; n = 21), and Alzheimer's disease (AD; n = 31) groups completed an expanded Multilingual Naming Test with a time-pressured administration procedure (MINT Sprint 2.0). Cerebrospinal fluid biomarkers classified participants as true controls (n = 61) or preclinical AD (n = 26).

RESULTS

Total correct MINT Sprint 2.0 scores exhibited good sensitivity and specificity (>0.85) for discriminating true controls from cognitively impaired (MCI/AD) groups and showed significant differences between true controls and preclinical AD groups. Time measurement did not improve classification, but percent resolved scores exhibited promise as an independent AD marker.

DISCUSSION

Naming deficits can be detected in the earliest stages of AD with tests and procedures designed for this purpose.

Different Aspects of Aging in Migraine

Migraine is a common neurological disease displaying an unusual dependence on age. For most patients, the peak intensity of migraine headaches occurs in 20s and lasts until 40s, but then headache attacks become less intense, occur less frequently and the disease is more responsive to therapy. This relationship is valid in both females and males, although the prevalence of migraine in the former is 2-4 times greater than the latter. Recent concepts present migraine not only as a pathological event, but rather as a part of evolutionary adaptive response to protect organism against consequences of stress-induced brain energy deficit. However, these concepts do not fully explain that unusual dependence of migraine prevalence on age. Many aspects of aging, both molecular/cellular and social/cognitive, are interwound in migraine pathogenesis, but they neither explain why only some persons are affected by migraine, nor suggest any causal relationship. In this narrative/hypothesis review we present information on associations of migraine with chronological aging, brain aging, cellular senescence, stem cell exhaustion as well as social, cognitive, epigenetic, and metabolic aging. We also underline the role of oxidative stress in these associations. We hypothesize that migraine affects only individuals who have inborn, genetic/epigenetic, or acquired (traumas, shocks or complexes) migraine predispositions. These predispositions weakly depend on age and affected individuals are more prone to migraine triggers than others. Although the triggers can be related to many aspects of aging, social aging may play a particularly important role as the prevalence of its associated stress has a similar age-dependence as the prevalence of migraine. Moreover, social aging was shown to be associated with oxidative stress, important in many aspects of aging. In perspective, molecular mechanisms underlying social aging should be further explored and related to migraine with a closer association with migraine predisposition and difference in prevalence by sex.

Fast-spiking parvalbumin-positive interneurons in brain physiology and Alzheimer's disease

Fast-spiking parvalbumin (PV) interneurons are inhibitory interneurons with unique morphological and functional properties that allow them to precisely control local circuitry, brain networks and memory processing. Since the discovery in 1987 that PV is expressed in a subset of fast-spiking GABAergic inhibitory neurons, our knowledge of the complex molecular and physiological properties of these cells has been expanding. In this review, we highlight the specific properties of PV neurons that allow them to fire at high frequency and with high reliability, enabling them to control network oscillations and shape the encoding, consolidation and retrieval of memories. We next discuss multiple studies reporting PV neuron impairment as a critical step in neuronal network dysfunction and cognitive decline in mouse models of Alzheimer's disease (AD). Finally, we propose potential mechanisms underlying PV neuron dysfunction in AD and we argue that early changes in PV neuron activity could be a causal step in AD-associated network and memory impairment and a significant contributor to disease pathogenesis.

Disruption of the autism gene and chromatin regulator KDM5A alters hippocampal cell identity

Chromatin regulation plays a pivotal role in establishing and maintaining cellular identity and is one of the top pathways disrupted in autism spectrum disorder (ASD). The hippocampus, composed of distinct cell types, is often affected in patients with ASD. However, the specific hippocampal cell types and their transcriptional programs that are dysregulated in ASD are unknown. Using single-nucleus RNA sequencing, we show that the ASD gene, lysine demethylase 5A (KDM5A), regulates the development of specific subtypes of excitatory and inhibitory neurons. We found that KDM5A is essential for establishing hippocampal cell identity by controlling a differentiation switch early in development. Our findings define a role for the chromatin regulator KDM5A in establishing hippocampal cell identity and contribute to the emerging convergent mechanisms across ASD.

The pentraxin family in autoimmune disease

The pentraxins represent a family of multifunctional proteins composed of long and short pentamers. The latter includes serum amyloid P component (SAP) and C-reactive protein (CRP) whereas the former includes neuronal PTX1 and PTX2 (NPTX1 and NPTX2, respectively), PTX3 and PTX4. These serve as a bridge between adaptive immunity and innate immunity and a link between inflammation and immunity. Similarities and differences between long and short pentamers are examined and their roles in autoimmune disease are discussed. Increased CRP and PTX3 could indicate the activity of rheumatoid arthritis, systemic lupus erythematosus or other autoimmune diseases. Mechanistically, CRP and PTX3 may predict target organ injury, regulate bone metabolic immunity and maintain homeostasis as well as participate in vascular endothelial remodeling. Interestingly, PTX3 is pleiotropic, being involved in inflammation and tissue repair. Given the therapeutic potential of PTX3 and CRP, targeting these factors to exert a beneficial effect is the focus of research efforts. Unfortunately, studies on NPTX1, NPTX2, PTX4 and SAP are scarce and more research is clearly needed to elaborate their potential roles in autoimmune disease.

Insulin resistance induces earlier initiation of cognitive dysfunction mediated by cholinergic deregulation in a mouse model of Alzheimer's disease

Although insulin resistance increases the risk of Alzheimer's disease (AD), the mechanisms remain unclear, partly because no animal model exhibits the insulin-resistant phenotype without persistent hyperglycemia. Here we established an AD model with whole-body insulin resistance without persistent hyperglycemia (APP/IR-dKI mice) by crossbreeding constitutive knock-in mice with P1195L-mutated insulin receptor (IR-KI mice) and those with mutated amyloid precursor protein (AppNL-G-F mice: APP-KI mice). APP/IR-dKI mice exhibited cognitive impairment at an earlier age than APP-KI mice. Since cholinergic dysfunction is a major characteristic of AD, pharmacological interventions on the cholinergic system were performed to investigate the mechanism. Antagonism to a nicotinic acetylcholine receptor α7 (nAChRα7) suppressed cognitive function and cortical blood flow (CBF) response to cholinergic-regulated peripheral stimulation in APP-KI mice but not APP/IR-dKI mice. Cortical expression of Chrna7, encoding nAChRα7, was downregulated in APP/IR-dKI mice compared with APP-KI. Amyloid β burden did not differ between APP-KI and APP/IR-dKI mice. Therefore, insulin resistance, not persistent hyperglycemia, induces the earlier onset of cognitive dysfunction and CBF deregulation mediated by nAChRα7 downregulation. Our mouse model will help clarify the association between type 2 diabetes mellitus and AD.

Extracellular matrix proteoglycans support aged hippocampus networks: a potential cellular-level mechanism of brain reserve

One hallmark of normative brain aging is vast heterogeneity in whether older people succumb to or resist cognitive decline. Resilience describes a brain's capacity to maintain cognition in the face of aging and disease. One factor influencing resilience is brain reserve-the status of neurobiological resources available to support neuronal circuits as dysfunction accumulates. This study uses a cohort of behaviorally characterized adult, middle-aged, and aged rats to test whether neurobiological factors that protect inhibitory neurotransmission and synapse function represent key components of brain reserve. Histochemical analysis of extracellular matrix proteoglycans, which play critical roles in stabilizing synapses and modulating inhibitory neuron excitability, was conducted alongside analyses of lipofuscin-associated autofluorescence. The findings indicate that aging results in lower proteoglycan density and more lipofuscin in CA3. Aged rats with higher proteoglycan density exhibited better performance on the Morris watermaze, whereas lipofuscin abundance was not related to spatial memory. These data suggest that the local environment around neurons may protect against synapse dysfunction or hyperexcitability and could contribute to brain reserve mechanisms.

Serum neuronal pentraxin 2 is related to cognitive dysfunction and electroencephalogram slow wave/fast wave frequency ratio in epilepsy

BACKGROUND

Cognitive dysfunction in epileptic patients is a high-incidence complication. Its mechanism is related to nervous system damage during seizures, but there is no effective diagnostic biomarker. Neuronal pentraxin 2 (NPTX2) is thought to play a vital role in neurotransmission and the maintenance of synaptic plasticity. This study explored how serum NPTX2 and electroencephalogram (EEG) slow wave/fast wave frequency ratio relate to cognitive dysfunction in patients with epilepsy.

AIM

To determine if serum NPTX2 could serve as a potential biomarker for diagnosing cognitive impairment in epilepsy patients.

METHODS

The participants of this study, conducted from January 2020 to December 2021, comprised 74 epilepsy patients with normal cognitive function (normal group), 37 epilepsy patients with cognitive dysfunction [epilepsy patients with cognitive dysfunction (ECD) group] and 30 healthy people (control group). The mini-mental state examination (MMSE) scale was used to evaluate cognitive function. We determined serum NPTX2 levels using an enzyme-linked immunosorbent kit and calculated the signal value of EEG regions according to the EEG recording. Pearson correlation coefficient was used to analyze the correlation between serum NPTX2 and the MMSE score.

RESULTS

The serum NPTX2 level in the control group, normal group and ECD group were 240.00 ± 35.06 pg/mL, 235.80 ± 38.01 pg/mL and 193.80 ± 42.72 pg/mL, respectively. The MMSE score was lowest in the ECD group among the three, while no significant difference was observed between the control and normal groups. In epilepsy patients with cognitive dysfunction, NPTX2 level had a positive correlation with the MMSE score (r = 0.367, P = 0.0253) and a negative correlation with epilepsy duration (r = -0.443, P = 0.0061) and the EEG slow wave/fast wave frequency ratio value in the temporal region (r = -0.339, P = 0.039).

CONCLUSION

Serum NPTX2 was found to be related to cognitive dysfunction and the EEG slow wave/fast wave frequency ratio in patients with epilepsy. It is thus a potential biomarker for the diagnosis of cognitive impairment in patients with epilepsy.

NPTX2 in Cerebrospinal Fluid Predicts the Progression From Normal Cognition to Mild Cognitive Impairment

OBJECTIVE

This study examined whether cerebrospinal fluid (CSF) baseline levels of the synaptic protein NPTX2 predict time to onset of symptoms of mild cognitive impairment (MCI), both alone and when accounting for traditional CSF Alzheimer's disease (AD) biomarker levels. Longitudinal NPTX2 levels were also examined.

METHODS

CSF was collected longitudinally from 269 cognitively normal BIOCARD Study participants (mean baseline age = 57.7 years; mean follow-up = 16.3 years; n = 77 progressed to MCI/dementia). NPTX2 levels were measured from 3 correlated peptides using quantitative parallel reaction monitoring mass spectrometry. Levels of Aβ42 /Aβ40 , p-tau181 , and t-tau were measured from the same CSF specimens using Lumipulse automated electrochemiluminescence assays.

RESULTS

In Cox regression models, lower baseline NPTX2 levels were associated with an earlier time to MCI symptom onset (hazard ratio [HR] = 0.76, SE = 0.09, p = 0.023). This association was significant for progression within 7 years (p = 0.036) and after 7 years from baseline (p = 0.001). Baseline NPTX2 levels improved prediction of time to MCI symptom onset after accounting for baseline AD biomarker levels (p < 0.01), and NPTX2 did not interact with the CSF AD biomarkers or APOE-ε4 genetic status. In linear mixed effects models, higher baseline p-tau181 and t-tau levels were associated with higher baseline levels of NPTX2 (both p < 0.001) and greater rates of NPTX2 declines over time.

INTERPRETATION

NPTX2 may be a valuable prognostic biomarker during preclinical AD that provides additive and independent prediction of MCI onset among individuals who are cognitively normal. We hypothesize that NPTX2-mediated circuit homeostasis confers resilience during the early phase of AD. ANN NEUROL 2023;94:620-631.