Hybrid Membrane-Coated Nanoparticles for Precise Targeting and Synergistic Therapy in Alzheimer's Disease.

The blood brain barrier (BBB) limits the application of most therapeutic drugs for neurological diseases (NDs). Hybrid cell membrane-coated nanoparticles derived from different cell types can mimic the surface properties and functionalities of the source cells, further enhancing their targeting precision and therapeutic efficacy. Neuroinflammation has been increasingly recognized as a critical factor in the pathogenesis of various NDs, especially Alzheimer's disease (AD). In this study, a novel cell membrane coating is designed by hybridizing the membrane from platelets and chemokine (C-C motif) receptor 2 (CCR2) cells are overexpressed to cross the BBB and target neuroinflammatory lesions. Past unsuccessful endeavors in AD drug development underscore the challenge of achieving favorable outcomes when utilizing single-mechanism drugs.Two drugs with different mechanisms of actions into liposomes are successfully loaded to realize multitargeting treatment. In a transgenic mouse model for familial AD (5xFAD), the administration of these drug-loaded hybrid cell membrane liposomes results in a significant reduction in amyloid plaque deposition, neuroinflammation, and cognitive impairments. Collectively, the hybrid cell membrane-coated nanomaterials offer new opportunities for precise drug delivery and disease-specific targeting, which represent a versatile platform for targeted therapy in AD.

Blood-based CNS regionally and neuronally enriched extracellular vesicles carrying pTau217 for Alzheimer's disease diagnosis and differential diagnosis.

Accurate differential diagnosis among various dementias is crucial for effective treatment of Alzheimer's disease (AD). The study began with searching for novel blood-based neuronal extracellular vesicles (EVs) that are more enriched in the brain regions vulnerable to AD development and progression. With extensive proteomic profiling, GABRD and GPR162 were identified as novel brain regionally enriched plasma EVs markers. The performance of GABRD and GPR162, along with the AD molecule pTau217, was tested using the self-developed and optimized nanoflow cytometry-based technology, which not only detected the positive ratio of EVs but also concurrently presented the corresponding particle size of the EVs, in discovery (n = 310) and validation (n = 213) cohorts. Plasma GABRD+- or GPR162+-carrying pTau217-EVs were significantly reduced in AD compared with healthy control (HC). Additionally, the size distribution of GABRD+- and GPR162+-carrying pTau217-EVs were significantly different between AD and non-AD dementia (NAD). An integrative model, combining age, the number and corresponding size of the distribution of GABRD+- or GPR162+-carrying pTau217-EVs, accurately and sensitively discriminated AD from HC [discovery cohort, area under the curve (AUC) = 0.96; validation cohort, AUC = 0.93] and effectively differentiated AD from NAD (discovery cohort, AUC = 0.91; validation cohort, AUC = 0.90). This study showed that brain regionally enriched neuronal EVs carrying pTau217 in plasma may serve as a robust diagnostic and differential diagnostic tool in both clinical practice and trials for AD.

Alzheimer's disease early diagnostic and staging biomarkers revealed by large-scale cerebrospinal fluid and serum proteomic profiling.

Amyloid-ß, tau pathology, and biomarkers of neurodegeneration make up the core diagnostic biomarkers of Alzheimer disease (AD). However, these proteins represent only a fraction of the complex biological processes underlying AD, and individuals with other brain diseases in which AD pathology is a comorbidity also test positive for these diagnostic biomarkers. More AD-specific early diagnostic and disease staging biomarkers are needed. In this study, we performed tandem mass tag proteomic analysis of paired cerebrospinal fluid (CSF) and serum samples in a discovery cohort comprising 98 participants. Candidate biomarkers were validated by parallel reaction monitoring-based targeted proteomic assays in an independent multicenter cohort comprising 288 participants. We quantified 3,238 CSF and 1,702 serum proteins in the discovery cohort, identifying 171 and 860 CSF proteins and 37 and 323 serum proteins as potential early diagnostic and staging biomarkers, respectively. In the validation cohort, 58 and 21 CSF proteins, as well as 12 and 18 serum proteins, were verified as early diagnostic and staging biomarkers, respectively. Separate 19-protein CSF and an 8-protein serum biomarker panels were built by machine learning to accurately classify mild cognitive impairment (MCI) due to AD from normal cognition with areas under the curve of 0.984 and 0.881, respectively. The 19-protein CSF biomarker panel also effectively discriminated patients with MCI due to AD from patients with other neurodegenerative diseases. Moreover, we identified 21 CSF and 18 serum stage-associated proteins reflecting AD stages. Our findings provide a foundation for developing blood-based tests for AD screening and staging in clinical practice.

CALHM2 V136G polymorphism reduces astrocytic ATP release and is associated with depressive symptoms and Alzheimer's disease risk.

INTRODUCTION: Depression is considered a prodromal state of Alzheimer's disease (AD), yet the underlying mechanism(s) by which depression increases the risk of AD are not known. METHODS: Single-nucleotide polymorphism (SNP) analysis was used to determine the CALHM2 variants in AD patients. Cellular and molecular experiments were conducted to investigate the function of CALHM2 V136G mutation. We generated a new genetically engineered Calhm2 V136G mouse model and performed behavioral tests with these mice. RESULTS: CALHM2 V136G mutation (rs232660) is significantly associated with AD. V136G mutation resulted in loss of the CALHM2 ATP-release function in astrocytes and impaired synaptic plasticity. Mice homozygous for the Calhm2 V136G allele displayed depressive-like behaviors that were rescued by administration of exogenous ATP. Moreover, Calhm2 V136G mutation predisposed mice to cognitive decline in old age. DISCUSSION: CALHM2 dysfunction is a biologically relevant mechanism that may contribute to the observed clinical correlation between depression and AD.

Identification and functional characterization of novel variants of MAPT and GRN in Chinese patients with frontotemporal dementia.

Frontotemporal dementia (FTD) is the second most common cause of dementia after Alzheimer's disease, characterized by distinct changes in behavior, personality, and language. Our study performed whole exome sequencing and repeat-primed PCR analysis in 29 unrelated FTD patients. Consequently, 2 known pathogenic variants (MAPT: p.P301L; TBK1: p.I450Kfs), and 4 novel variants (MAPT: p.R406Q, p.D430H, p.A330D; GRN: c.350-2A>G) were identified. The functional analysis results showed that phosphorylated tau levels were higher in cells expressing p.R406Q and p.D430H tau than those expressing wild-type tau, especially at the Thr205, Thr231, and Ser396 phosphorylation epitopes. Besides, the p.R406Q and p.D430H variants of MAPT impaired the ability of tau to bind to the microtubules and increased tau self-aggregation. Furthermore, we found that the c.350-2A>G variant caused exon 5 skipping. Our results showed that p.R406Q, p.D430H, and c.350-2A>G variants were classified as pathogenic. Finally, we summarized the clinical characterization of patients carrying pathogenic variants of MAPT in the East Asia populations. Our results broaden the genetic spectrum of FTD with MAPT and GRN variants.

Discerning the Role of Blood Brain Barrier Dysfunction in Alzheimer's Disease.

Alzheimer's disease (AD) is the most common form of neurodegenerative disease. The predominant characteristics of AD are the accumulation of amyloid-ß (Aß) and hyperphosphorylated tau in the brain. Blood brain barrier (BBB) dysfunction as one of the causative factors of cognitive impairment is increasingly recognized in the last decades. However, the role of BBB dysfunction in AD pathogenesis is still not fully understood. It remains elusive whether BBB dysfunction is a consequence or causative fact of Aß pathology, tau pathology, neuroinflammation, or other conditions. In this review, we summarized the major findings of BBB dysfunction in AD and the reciprocal relationships between BBB dysfunction, Aß pathology, tau pathology, and neuroinflammation. In addition, the implications of BBB dysfunction in AD for delivering therapeutic drugs were presented. Finally, we discussed how to better determine the underlying mechanisms between BBB dysfunction and AD, as well as how to explore new therapies for BBB regulation to treat AD in the future.

Inflammatory markers of hemogram parameters as predictive factors for disease severity in anti-N-methyl-D-aspartate receptor encephalitis.

OBJECTIVE: This study aimed to investigate the utility of inflammatory markers of hemogram parameters as objective indicators of disease severity in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. METHODS: A total of 98 patients were retrospectively reviewed. Inflammatory markers of hemogram parameters, including neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), and platelet-lymphocyte ratio, were acquired within 24 h of admission. We then analyzed their utility as predictive factors for disease severity at different time points assessing with the modified Rankin Scale (mRS). RESULTS: There were 49 patients in the mild group (mRS ≤ 2) and 49 patients in the moderate-to-severe (mRS > 2) group at admission. The moderate-to-severe group presented more frequently with psychiatric symptoms and central hypoventilation, as well as a lower lymphocyte count, a higher neutrophil count, a higher NLR and a higher MLR (all p < 0.05) when compared with the mild group. NLR and MLR showed similar positive correlations with mRS scores (r = 0.40, r = 0.40, both p < 0.001). Further multivariate logistic regression analyses indicated that NLR > 4.232 was an independent risk factor for moderate-to-severe status at admission. Meanwhile, NLR and MLR were associated with disease severity at different stages of follow-up but showed no independent predictive value. CONCLUSION: Our findings suggested that NLR was an independent risk factor for moderate-to-severe status in the initial stage of anti-NMDAR encephalitis with a cut-off value of > 4.232.

Microglial Activation, Tau Pathology, and Neurodegeneration Biomarkers Predict Longitudinal Cognitive Decline in Alzheimer's Disease Continuum.

Purpose: Biomarkers used for predicting longitudinal cognitive change in Alzheimer's disease (AD) continuum are still elusive. Tau pathology, neuroinflammation, and neurodegeneration are the leading candidate predictors. We aimed to determine these three aspects of biomarkers in cerebrospinal fluid (CSF) and plasma to predict longitudinal cognition status using Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. Patients and Methods: A total of 430 subjects including, 96 cognitive normal (CN) with amyloid ß (Aß)-negative, 54 CN with Aß-positive, 195 mild cognitive impairment (MCI) with Aß-positive, and 85 AD with amyloid-positive (Aß-positive are identified by CSF Aß42/Aß40 < 0.138). Aß burden was evaluated by CSF and plasma Aß42/Aß40 ratio; tau pathology was evaluated by CSF and plasma phosphorylated-tau (p-tau181); microglial activation was measured by CSF soluble TREM2 (sTREM2) and progranulin (PGRN); neurodegeneration was measured by CSF and plasma t-tau and structural magnetic resonance imaging (MRI); cognition was examined annually over the subsequent 8 years using the Alzheimer's Disease Assessment Scale Cognition 13-item scale (ADAS13) and Mini-Mental State Exam (MMSE). Linear mixed-effects models (LME) were applied to assess the correlation between biomarkers and longitudinal cognition decline, as well as their effect size on the prediction of longitudinal cognitive decline. Results: Baseline CSF Aß42/Aß40 ratio was decreased in MCI and AD compared to CN, while CSF p-tau181 and t-tau increased. Baseline CSF sTREM2 and PGRN did not show any differences in MCI and AD compared to CN. Baseline brain volumes (including the hippocampal, entorhinal, middle temporal lobe, and whole-brain) decreased in MCI and AD groups. For the longitudinal study, there were significant interaction effects of CSF p-tau181 × time, plasma p-tau181 × time, CSF sTREM2 × time, and brain volumes × time, indicating CSF, and plasma p-tau181, CSF sTREM2, and brain volumes could predict longitudinal cognition deterioration rate. CSF sTREM2, CSF, and plasma p-tau181 had similar medium prediction effects, while brain volumes showed stronger effects in predicting cognition decline. Conclusion: Our study reported that baseline CSF sTREM2, CSF, and plasma p-tau181, as well as structural MRI, could predict longitudinal cognitive decline in subjects with positive AD pathology. Plasma p-tau181 can be used as a relatively noninvasive reliable biomarker for AD longitudinal cognition decline prediction.

Early-Onset Parkinson's Disease and Brain Iron Accumulation Caused by a Novel Homozygous DJ-1 Mutation.

DJ-1 mutations are rare causes of autosomal recessive early-onset Parkinson's disease (AR-EOPD) and relatively rarely reported in the Chinese population. Here, we used the whole-exome sequencing and Sanger sequencing to investigate DJ-1 mutations in the Chinese population and confirmed the pathogenicity of the mutation using primary fibroblasts established from skin biopsies. We identified a novel homozygous mutation (c.390delA, p.D131Tfs*3) in DJ-1 in a consanguineous Chinese family. The proband in this family had parkinsonism at the age of 22. His brain MRI indicated brain iron accumulation in the basal ganglia and cerebellum. The novel mutation caused DJ-1 protein deficiency, led to mitochondrial dysfunction, inhibited cell proliferation, and anti-oxidant defense.

Alzheimer's disease susceptibility locus in CD2AP is associated with increased cerebrospinal fluid tau levels in mild cognitive impairment.

INTRODUCTION: Rs9296559 within CD2-associated protein (CD2AP) has been identified as a susceptibility locus for Alzheimer's disease (AD). Recent studies indicated that CD2AP functioned as a regulator of endocytic trafficking to modulate the ß-amyloid (Aß) generation in neurons. Moreover, knockdown of cindr, the Drosophila ortholog of CD2AP, enhanced tau-induced neurodegeneration, implying CD2AP also participated in tau pathology. However, the role of rs9296559 in regulating Aß and tau metabolism in AD was still unclear. METHODS: Here, the associations of rs9296559 with CSF Aß1-42, p-tau, and t-tau were performed using a linear regression model in a total of 543 cognitive normal (CN), mild cognitive impairment (MCI), and AD subjects from the Alzheimer's disease Neuroimaging Initiative (ADNI) cohort. The results were replicated in an independent cohort consisting of 198 Chinese subjects recruited from our hospital. RESULTS: In the ADNI cohort, CC + TC genotypes significantly increased CSF t-tau and p-tau levels in MCI patients but did not alter CSF tau levels in AD. This association was also observed in the replication cohort. Moreover, there was no association between rs9296559 and CSF Aß1-42 level at different disease statuses in the two cohorts. CONCLUSION: Our findings showed that rs9296559 was associated with higher CSF t-tau and p-tau levels in MCI, supporting that CD2AP modified AD risk by altering tau-related neurodegeneration in the early stage of the AD continuum. To the best of our knowledge, this is the first study to evaluate the association between CD2AP genotypes and AD CSF biomarkers.

Optimal Combinations of AT(N) Biomarkers to Determine Longitudinal Cognition in the Alzheimer's Disease.

Background: National Institute on Aging-Alzheimer's Association (NIA-AA) proposed the AT(N) system based on ß-amyloid deposition, pathologic tau, and neurodegeneration, which considered the definition of Alzheimer's disease (AD) as a biological construct. However, the associations between different AT(N) combinations and cognitive progression have been poorly explored systematically. The aim of this study is to compare different AT(N) combinations using recognized biomarkers within the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. Methods: A total of 341 participants were classified into cognitively unimpaired (CU; n = 200) and cognitively impaired (CI; n = 141) groups according to the clinical manifestations and neuropsychological tests. Cerebrospinal fluid (CSF) Aß42 and amyloid-PET ([18F]flutemetamol) were used as biomarkers for A; CSF phosphorylated tau (p-tau) and tau-PET ([18F]flortaucipir) were used as biomarkers for T; CSF total tau (t-tau), hippocampal volume, temporal cortical thickness, [18F]fluorodeoxyglucose (FDG) PET, and plasma neurofilament light (NfL) were used as biomarkers for (N). Binary biomarkers were obtained from the Youden index and publicly available cutoffs. Prevalence of AT(N) categories was compared between different biomarkers within the group using related independent sample non-parametric test. The relationship between AT(N) combinations and 12-year longitudinal cognition was assessed using linear mixed-effects modeling. Results: Among the CU participants, A-T-(N)- was most common. More T+ were detected using p-tau than tau PET (p < 0.05), and more (N)+ were observed using fluid biomarkers (p < 0.001). A+T+(N)+ was more common in the CI group. Tau PET combined with cortical thickness best predicted cognitive changes in the CI group and MRI predicted changes in the CU group. Conclusions: These findings suggest that optimal AT(N) combinations to determine longitudinal cognition differ by cognitive status. Different biomarkers within a specific component for defining AT(N) cannot be used identically. Furthermore, different strategies for discontinuous biomarkers will be an important area for future studies.

Morvan syndrome associated with LGI1 antibody: a case report.

BACKGROUND: Morvan syndrome (MoS) is a rare autoimmune syndrome associated with antibodies against two kinds of potassium channel proteins, contactin associated protein-like 2 (CASPR2) and leucine-rich glioma inactivated protein 1 (LGI1). MoS patients with only LGI1-antibody seropositivity have rarely been reported. Here, we describe a 64-year-old male MoS patient with only LGI1-antibody seropositivity. CASE PRESENTATION: A 64-year-old male patient was referred to our hospital due to limb pain, widespread myokymia, insomnia, constipation, and hyperhidrosis for 1 month. The patient was diagnosed with MoS based on the clinical symptoms and positive LGI1-antibody in serum. He was treated with intravenous immunoglobulin (IVIG), intravenous methylprednisolone followed by oral prednisone, and other drugs for symptomatic relief. Several days later, myokymia and insomnia symptoms improved. After 60 days of follow-up, all the drugs had been stopped for 2 weeks, and the patient achieved complete remission without any medical side effects. CONCLUSION: We report the clinical characteristics of a Chinese MoS patient with only LGI1-antibody seropositivity, and further support the view that non-neoplasm MoS patients respond well to immunotherapy.

Application of Cerebrospinal Fluid AT(N) Framework on the Diagnosis of AD and Related Cognitive Disorders in Chinese Han Population.

BACKGROUND: Studies concerning the impact of the AT(N) framework on diagnostic capability in the dementia population are lacking. We aimed to explore the diagnostic application of CSF AT(N) framework in clinical routines of Alzheimer's disease (AD) as well as differential diagnosis of other cognitive diseases in the Chinese Han population. PATIENTS AND METHODS: A total of 137 patients with cognitive disorders received CSF tests of Aß42, t-tau and p-tau181. Their CSF biomarker results were categorized and interpreted by the AT(N) framework. Neurologists provided a diagnosis both pre- and post-CSF biomarker disclosure with corresponding diagnostic confidence. RESULTS: The total initial diagnosis included 79 patients with AD and 58 patients with non-AD (NAD). The results of CSF biomarkers led to a diagnostic change of 28% in the cohort. Approximately 81.5% (n=53) of 65 patients whose CSF biomarker showed an underlying AD pathology were finally diagnosed as AD, with an increase of 17.5% in diagnostic confidence. Thirty-seven CSF results indicating NAD pathologic changes contributed to an exclusion of AD in 56.8% (n=21) of the patients along with a modest increase of 9.8% in average confidence. Thirty-five patients with normal CSF biomarkers maintained the diagnosis of NAD in 68.6% (n=24) of the group, leading to a slight elevation of 7.6% in confidence. CONCLUSION: We found that the presence of amyloid pathology (A+) is contributable to diagnosing AD and improving confidence. On occasion of negative amyloid pathology (A-), with or without tau pathology, gaining uncertainty of the primary AD diagnosis would diminish the corresponding confidence. To the best of our knowledge, this is the first study performed in the Chinese Han population with cognitive disorders that explores the clinical capability of CSF AT(N) framework in a quantitative way.

The role of P2X7R in neuroinflammation and implications in Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of dementia and is set to rise in prevalence as the global trends in population aging. The extracellular deposition of amyloid protein (Aß) and the intracellular formation of neurofibrillary tangles in the brain have been recognized as the two core pathologies of AD. Over the past decades, the presence of neuroinflammation in the brain has been documented as the third core pathology of AD. In recent years, emerging evidence demonstrated that the purinergic receptor P2X7 (P2X7R) serves a critical role in microglia responses and neuroinflammation. Besides, targeting P2X7R by genetic or pharmacological strategies attenuates the symptoms and pathological changes of AD models, and P2X7R has been recognized as a promising therapeutic target for AD. In this review, we summarized the recent evidence concerning the roles of P2X7R in neuroinflammation and implications in AD pathogenesis.

Genetic Analysis of Chinese Patients with Early-Onset Dementia Using Next-Generation Sequencing.

OBJECTIVE: Early-onset dementia (EOD) is a relatively uncommon form of dementia that afflicts people before age 65. Only a few studies analyzing the genetics of EOD have been performed in the Chinese Han population. Diagnosing EOD remains a challenge due to the diverse genetic and clinical heterogeneity of these diseases. The aim of this study was to investigate the genetic spectrum and clinical features of Chinese patients with EOD. MATERIALS AND METHODS: A total of 49 EOD patients were recruited. Targeted next-generation (NGS) analyses were performed to screen for all of the known genes associated with dementia. Possible pathogenic variants were confirmed by performing Sanger sequencing. The genetic spectrum and clinical features of the EOD patients were analyzed. RESULTS: Seven previously reported pathogenic variants (p.I213T and p.W165C in PSEN1; p.D678N in APP; c.1349_1352del in TBK1; p.P301L and p.R406W in MAPT; p.R110C in NOTCH3) and two novel variants of uncertain significance (p.P436L in PSEN2; c.239-11G>A in TARDBP) were identified. CONCLUSION: Our study demonstrated the genetic spectrum and clinical features of EOD patients, and it reveals that genetic testing of known causal genes in EOD patients can help to make a precise diagnosis.

Novel ATP13A2 and PINK1 variants identified in Chinese patients with Parkinson's disease by whole-exome sequencing.

Genetic factors are considered to play a critical role in patients with early-onset Parkinson's disease (EOPD). The genetic spectrum of EOPD patients has been extensively investigated in Caucasian populations but rarely in the Chinese population. In this study, a total of 21 unrelated Chinese EOPD patients were enrolled. Multiplex ligation-dependent probe amplification assay and whole-exome sequencing were performed, followed by Sanger sequencing. Detailed clinical features were presented. Two novel likely pathogenic variants (p.Q648X in ATP13A2 and p.N521fs in PINK1) and 10 previously reported Parkin pathogenic variations (exon 2 deletion, exon 3-4 deletion, exon 4 deletion, exon 6-7 deletion, exon 7 deletion; p.G284R, p.G329 V, p.R366W, p.N428fs, p.M458 L) were identified in 9 out of 21 (42.86%) patients. The frequency (33.33%) of Parkin variations is much higher in our cohort than that in the East Asian population. The patient carrying the ATP13A2 variant showed no response to levodopa treatment. Our findings broaden the genetic spectrum and clinical features of EOPD patients.

Identification of susceptibility loci for cognitive impairment in a cohort of Han Chinese patients with Parkinson's disease.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. Identifying PD cognitive impairment (PDCI) in the early stage will help slow or prevent PD dementia. Susceptibility loci for PDCI are inconsistent in different studies. The aim of this study is to determine susceptibility loci for PDCI in the Han Chinese population. A total of 24 single nucleotide polymorphisms (SNPs) associated with PDCI were genotyped by Massarray system and Sanger sequencing in 158 PD patients and 275 healthy controls. Two SNPs (rs34778348 in LRRK2, rs78973108 in GBA) had different genotype distribution between PD and controls. None of risk SNPs was identified between PDCI and PD with normal cognition (PDNC). Aging and high Unified Parkinson's Disease Rating Scale (UPDRS) score were the independent risk factors for PDCI, rather than sex and SNPs. Our study showed that none of risk SNPs was identified to be significantly associated with cognitive decline of PD patients, indicating the effect of susceptibility loci on PDCI is subtle in the Han Chinese population.

Primary age-related tauopathy in a Chinese cohort.

Primary age-related tauopathy (PART) is characterized by the presence of tau neurofibrillary tangles (NFTs) which are typically observed in Alzheimer's disease (AD) brains, with few or without ß-amyloid (Aß) plaques. The diagnosis of PART can be categorized into "definite" or "possible" depending on the amount of Aß plaques. Definite PART is diagnosed when NFTs are observed and the Braak stage is ≤IV, with Thal Aß Phase 0 (Crary et al., 2014). According to the neuropathological diagnostic criteria, we reported that PART was frequently observed in the Chinese population according to our findings from specimens in our brain bank, with 47% of brain bank subjects meeting the criteria for PART. There is no consensus on the nature of PART. It remains to be elucidated whether PART is an early form of AD or a novel tauopathy (Duyckaerts et al., 2015; Jellinger et al., 2015).