Vo Van Giau

Role of inflammatory molecules in the Alzheimer's disease progression and diagnosis

Alzheimers disease (AD) is a complex disorder and the most common form of neurodegenerative dementia. Several genetic, environmental, and physiological factors, including inflammations and metabolic influences, are involved in the progression of AD. Inflammations are composed of complicated networks of many chemokines and cytokines with diverse cells. Inflammatory molecules are needed for the protection against pathogens, and maintaining their balances is important for normal physiological function. Recent studies demonstrated that inflammation may be involved in neurodegenerative dementia. Cellular immune components, such as microglia or astrocytes, mediate the release of inflammatory molecules, including tumor necrosis factor, growth factors, adhesion molecules, or chemokines. Over- and underexpression of pro- and anti-inflammatory molecules, respectively, may result in neuroinflammation and thus disease initiation and progression. In addition, levels of several inflammatory factors were reported to be altered in the brain or bodily fluids of patients with AD, reflecting their neuropathological changes. Therefore, simultaneous detection of several inflammatory molecules in the early or pre-symptomatic stage may improve the early diagnosis of AD. Further studies are needed to determine, how induction or inhibition of inflammatory factors could be used for AD therapies. This review summarizes the role or possible role of immune cells and inflammatory molecules in disease progression or prevention.

Emergence of exosomal miRNAs as a diagnostic biomarker for Alzheimer's disease.

Alzheimers disease (AD) is the most common progressive degenerative disorder, and is characterized by memory loss and cognitive decline. It is a complex disorder with both environmental and genetic components. Current diagnosis of AD is based primarily on the analysis of the patients cognitive function using imaging techniques and the biochemical analyses of bodily fluids. Efforts have been made to develop not only an effective therapeutic, but also a diagnostic capable of identifying AD before the onset of irreversible neurological damage. The molecular content of exosomes is a fingerprint of the releasing cell type and its status. A significant body of literature has demonstrated that molecular constituents of exosomes, especially exosomal proteins and microRNAs (miRNAs), hold great promise as novel biomarkers for clinical diagnosis. In addition, expression profiling of miRNAs found in nanovesicles has revealed diagnostic potential in neurodegenerative diseases. Currently, exosomal miRNAs within biological fluids are known as good disease-related markers, and have emerged as a powerful tool for solving many difficulties in both the diagnosis and treatment of AD patients. In this review, we reviewed recent advances in the research of exosomal biomarkers as well as exosomal miRNAs, summarized of actively used approaches to identifying potential miRNA biomarkers through mouse models and their potential application in clinical diagnostics in AD. We also supply a comprehensive overview of the formation, function, and isolation of exosomes.

Role of apolipoprotein E in neurodegenerative diseases.

Apolipoprotein E (APOE) is a lipid-transport protein abundantly expressed in most neurons in the central nervous system. APOE-dependent alterations of the endocytic pathway can affect different functions. APOE binds to cell-surface receptors to deliver lipids and to the hydrophobic amyloid-β peptide, regulating amyloid-β aggregations and clearances in the brain. Several APOE isoforms with major structural differences were discovered and shown to influence the brain lipid transport, glucose metabolism, neuronal signaling, neuroinflammation, and mitochondrial function. This review will summarize the updated research progress on APOE functions and its role in Alzheimer’s disease, Parkinson’s disease, cardiovascular diseases, multiple sclerosis, type 2 diabetes mellitus, Type III hyperlipoproteinemia, vascular dementia, and ischemic stroke. Understanding the mutations in APOE, their structural properties, and their isoforms is important to determine its role in various diseases and to advance the development of therapeutic strategies. Targeting APOE may be a potential approach for diagnosis, risk assessment, prevention, and treatment of various neurodegenerative and cardiovascular diseases in humans.

Gene panels and primers for next generation sequencing studies on neurodegenerative disorders

Several types of neurodegenerative diseases were described, including Alzheimer’s disease (AD), frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), prion disease, and Parkinson’s disease (PD). Since the potential treatment strategies of these disorders might be more successful in the pre-clinical stages than in the actual clinical setup, new diagnostic methods were needed. The involvement of heredity in neurodegenerative disorders was established, but several neurodegenerative disorders such as AD, PD, ALS, FTD and Huntington’s disease (HD) are highly complex. Sanger sequencing was used to detect mutations that are causative or risk factors for diseases. The problem with standard sequencing is its high cost and low speed. Recently, next generation sequencing (NGS) strategies were developed, which could provide a more complex genetic analysis of patients with neurodegenerative diseases. In this study, 50 genes were selected, which were established as causative genes for neurodegenerative diseases, but we also included several risk factor genes and candidate genes. Primers (maximum 400-bp length) were designed to screen for mutations and variants in them. We plan to use these primers for NGS screening to create a more detailed genetic profile for these patients. This study could enhance disease diagnosis and would be also helpful in estimating the risk for disease onset in the future.

Analysis of Cerebrospinal Fluid and [11C]PIB PET Biomarkers for Alzheimer’s Disease with Updated Protocols

BACKGROUND Recently, a Korean research group suggested a consensus protocol, based on the Alzheimers Disease Neuroimaging Initiative study protocol but with modifications for minimizing the confounding factors, for the evaluation of cerebrospinal fluid (CSF) biomarkers. OBJECTIVE Here, we analyzed fluid and imaging biomarkers of Alzheimers disease (AD) in Korean population. We used the updated protocol to propose a more accurate CSF biomarker value for the diagnosis of AD. METHODS Twenty-seven patients with AD and 30 cognitively normal controls (NC) were enrolled. CSF was collected from 55 subjects (patients with AD = 26, NC = 29) following the Korea consensus protocol. CSF biomarkers were measured using the INNO-BIA AlzBio3 immunoassay, and Pittsburgh compound B (PIB) positron emission tomography (PET) scans were also performed. RESULTS The cutoff values of CSF amyloid beta 1-42 (Aβ42), total tau (t-Tau), and phosphorylated tau (p-Tau) proteins were 357.1 pg/ml, 83.35 pg/ml, and 38.00 pg/ml, respectively. The cutoff values of CSF t-Tau/Aβ42 and p-Tau/Aβ42 ratio- were 0.210 (sensitivity 100%, specificity 86.21%) and 0.1350 (sensitivity 88.46%, specificity of 92.86%). The concordance rate with PIB-PET was higher using the CSF t-Tau/Aβ42 ratio (κ= 0.849, CI 0.71-0.99) than CSF Aβ42 alone (κ= 0.703, CI 0.51-0.89). CONCLUSIONS Here, we improved controversial factors associated with the previous CSF study protocol and suggested a new cutoff value for the diagnosis of AD. Our results showed good diagnostic performance for differentiation of AD. Thus, we expect our findings could be a cornerstone in the establishment and clinical application of biomarkers for AD diagnosis.

Current advances in transdermal delivery of drugs for alzheimer's disease

Alzheimers disease (AD) is a common, progressive, fatal neurodegenerative disorder, which will play an increasingly important role both socially and financially in the aging populations. Treatments for AD show modest improvements in cognition and global functioning among patients. Furthermore, the oral administration of treating AD has had some drawbacks that decrease the medication adherence and efficacy of the therapy. Transdermal drugs are proposed as an alternative remedy to overcome the disadvantages of current pharmaceutical dosage options for this chronic disorder. They could have different strengths, such as offering a stable diffusion of active substance, avoiding the first pass metabolism, and reducing system adverse reactions. This article reviews the technical principles, novel techniques of transdermal delivery drug, and prospects for future development for the management of cognitive and behavioral dysfunctions in AD patients.

Genome-editing applications of CRISPR–Cas9 to promote in vitro studies of Alzheimer’s disease

Genetic variations play an important role in the clinical presentation and progression of Alzheimer’s disease (AD), especially early-onset Alzheimer’s disease. Hundreds of mutations have been reported with the majority resulting from alterations in β-amyloid precursor protein (APP), presenilin 1 (PSEN1), or presenilin 2 (PSEN2) genes. The roles of these mutations in the pathogenesis of AD have been classically confirmed or refuted through functional studies, where the mutations are cloned, inserted into cell lines, and monitored for changes in various properties including cell survival, amyloid production, or Aβ42/40 ratio. However, these verification studies tend to be expensive, time consuming, and inconsistent. Recently, the clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR–Cas9) system was developed, which improves sequence-specific gene editing in cell lines, organs, and animals. CRISPR–Cas9 is a promising tool for the generation of models of human genetic diseases and could facilitate the establishment of new animal AD models and the observation of dynamic bioprocesses in AD. Here, we recapitulated the history of CRISPR technology, recent progress, and, especially, its potential applications in AD-related genetic, animal modeling, and functional studies.

Characterization of mutations in PRNP (prion) gene and their possible roles in neurodegenerative diseases

Abnormal prion proteins are responsible for several fatal neurodegenerative diseases in humans and in animals, including Creutzfeldt–Jakob disease (CJD), Gerstmann–Sträussler–Scheinker disease, and fatal familial insomnia. Genetics is important in prion diseases, but in the most cases, cause of diseases remained unknown. Several mutations were found to be causative for prion disorders, and the effect of mutations may be heterogeneous. In addition, different prion mutations were suggested to play a possible role in additional phenotypes, such as Alzheimer’s type pathology, spongiform encephalopathy, or frontotemporal dementia. Pathogenic nature of several prion mutations remained unclear, such as M129V and E219K. These two polymorphic sites were suggested as either risk factors for different disorders, such as Alzheimer’s disease (AD), variant CJD, or protease-sensitive prionopathy, and they can also be disease-modifying factors. Pathological overlap may also be possible with AD or progressive dementia, and several patients with prion mutations were initially diagnosed with AD. This review also introduces briefly the diagnosis of prion diseases and the issues with their diagnosis. Since prion diseases have quite heterogeneous phenotypes, a complex analysis, a combination of genetic screening, cerebrospinal fluid biomarker analysis and imaging technologies could improve the early disease diagnosis.

Novel PSEN1 p.Gly417Ala mutation in a Korean patient with early-onset Alzheimer's disease with parkinsonism

Mutations in presenilin 1 (PSEN1) are the most common cause of autosomal dominant Alzheimers disease. Here, we report a 37-year-old male Korean patient carrying a PSEN1 p.Gly417Ala mutation with exceptionally early and severe presentations, including a wide range of atypical symptoms of rapid cognitive decline with a stooped posture, rigidity, and bradykinesia. Targeted next-generation sequencing of proband revealed a novel nucleotide substitution (c.1250G>C) in exon 12 of PSEN1 gene, altering glycine to alanine at 417 position. Three-dimensional protein structure prediction revealed that the variant may cause perturbations in the 8th transmembrane region, perturbing its functions from the increased hydrophobicity and size of alanine with decreased flexibility. Since several glycine>alanine substitutions in other PSEN1 transmembrane helices revealed aggressive Alzheimers disease phenotypes, PSEN1 Gly417Ala may share a common pathogenic mechanism.

Clinical genetic strategies for early onset neurodegenerative diseases

Purpose of reviewMethods for the genetic diagnosis of neurodegenerative disorders were reviewed, including their backgrounds and applications in the laboratory. Majority of disease-causing gene mutations were uncommon in the general population, where dominant variations could be easily identified in certain disorders. The development of molecular, next generation sequencing (NGS) and cytogenetic techniques allowed to identify multiple genetic mutations leading to diseases. Using of the accurate multivariate diagnosis of diseases would be essential for appropriate treatment of patients, genetic counseling and prevention strategiesRecent findingsAbnormal genes play an extremely important role in the pathogenesis of neurodegenerative disorders of the nervous system. Many studies of genetic have clearly indicated that the molecular mechanisms underlying the etiology and pathogenesis of most neurodegenerative disorders until now. Mutation is necessary for life, while fidelity is necessary for DNA replication. Mistakes in DNA replication/transcription can cause cells to produce either too much or too little protein or a defective protein. Studies on mutations have revealed the normal functions of genes, messages, proteins, the causes of many diseases, and the variability of responses among individuals. Based on the presence of damaging variants, there are many genes have identified that associated with neurodegenerative disorders through to genetic analyses of patients. This declaration is interesting because also our previous analysis has shown that several types of neurodegenerative diseases associated with abnormal genes function have been well described, including Alzheimer’s disease (AD), front temporal dementia (FTD), amyotrophic lateral sclerosis (ALS), prion disease, and Parkinson’s disease (PD). Since the potential treatment strategies for these disorders may be more successful during the pre-clinical stages than in the actual clinical setup, accurate, simple, and affordable diagnostic methods are needed. A mutation can be defined as a sequence change in a test sample compared to the sequence of a reference standard. This has led to the development of methods for screening and detecting abnormal DNA, including techniques that detect previously described mutations (genotyping) and those that scan for mutations in a particular target region (mutation scanning). This review provides a broad overview of the range of currently available mutation detection techniques with special emphasis on neurodegenerative disorders in humans. We have discussed the methods used for detecting unknown mutations, such as ribonuclease, denaturing gradient-gel electrophoresis, carbodiimide, chemical cleavage, single- strand conformation polymorphism, heteroduplex, and sequencing. Furthermore, other diagnostic methods for testing mutations include allele-specific oligonucleotide hybridization; allele-specific amplification, ligation, primer extension, and the artificial introduction of restriction sites are also reviewed. In order to identify the mutation, the last of the work provides basic insights into some of the most popular in silico tools for splicing defect prediction from the viewpoint of end users.