Subsequent correlated changes in complement component 3 and amyloid beta oligomers in the blood of patients with Alzheimer's disease.

INTRODUCTION: Alzheimer's disease (AD) involves the complement cascade, with complement component 3 (C3) playing a key role. However, the relationship between C3 and amyloid beta (Aß) in blood is limited. METHODS: Plasma C3 and Aß oligomerization tendency (AßOt) were measured in 35 AD patients and 62 healthy controls. Correlations with cerebrospinal fluid (CSF) biomarkers, cognitive impairment, and amyloid positron emission tomography (PET) were analyzed. Differences between biomarkers were compared in groups classified by concordances of biomarkers. RESULTS: Plasma C3 and AßOt were elevated in AD patients and in CSF or amyloid PET-positive groups. Weak positive correlation was found between C3 and AßOt, while both had strong negative correlations with CSF Aß42 and cognitive performance. Abnormalities were observed for AßOt and CSF Aß42 followed by C3 changes. DISCUSSION: Increased plasma C3 in AD are associated with amyloid pathology, possibly reflecting a defense response for Aß clearance. Further studies on Aß-binding proteins will enhance understanding of Aß mechanisms in blood.

Role of Calcitriol and Vitamin D Receptor (VDR) Gene Polymorphisms in Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by amyloid beta (Aß) buildup and neuronal degeneration. An association between low serum vitamin D levels and an increased risk of AD has been reported in several epidemiological studies. Calcitriol (1,25-dihydroxycholecalciferol) is the active form of vitamin D, and is generated in the kidney and many other tissues/organs, including the brain. It is a steroid hormone that regulates important functions like calcium/phosphorous levels, bone mineralization, and immunomodulation, indicating its broader systemic significance. In addition, calcitriol confers neuroprotection by mitigating oxidative stress and neuroinflammation, promoting the clearance of Aß, myelin formation, neurogenesis, neurotransmission, and autophagy. The receptors to which calcitriol binds (vitamin D receptors; VDRs) to exert its effects are distributed over many organs and tissues, representing other significant roles of calcitriol beyond sustaining bone health. The biological effects of calcitriol are manifested through genomic (classical) and non-genomic actions through different pathways. The first is a slow genomic effect involving nuclear VDR directly affecting gene transcription. The association of AD with VDR gene polymorphisms relies on the changes in vitamin D consumption, which lowers VDR expression, protein stability, and binding affinity. It leads to the altered expression of genes involved in the neuroprotective effects of calcitriol. This review summarizes the neuroprotective mechanism of calcitriol and the role of VDR polymorphisms in AD, and might help develop potential therapeutic strategies and markers for AD in the future.

Neuroprotection by Anethum graveolens (Dill) Seeds and Its Phytocompounds in SH-SY5Y Neuroblastoma Cell Lines and Acellular Assays.

Neurodegeneration diseases (NDs) are a group of complex diseases primarily characterized by progressive loss of neurons affecting mental function and movement. Oxidative stress is one of the factors contributing to the pathogenesis of NDs, including Alzheimer's disease (AD). These reactive species disturb mitochondrial function and accelerate other undesirable conditions including tau phosphorylation, inflammation, and cell death. Therefore, preventing oxidative stress is one of the imperative methods in the treatment of NDs. To accomplish this, we prepared hexane and ethyl acetate extracts of Anethum graveolens (dill) and identified the major phyto-components (apiol, carvone, and dihydrocarvone) by GC-MS. The extracts and major bioactives were assessed for neuroprotective potential and mechanism in hydrogen peroxide-induced oxidative stress in the SH-SY5Y neuroblastoma cell model and other biochemical assays. The dill (extracts and bioactives) provided statistically significant neuroprotection from 0.1 to 30 µg/mL by mitigating ROS levels, restoring mitochondrial membrane potential, reducing lipid peroxidation, and reviving the glutathione ratio. They moderately inhibited acetylcholine esterase (IC50 dill extracts 400-500 µg/mL; carvone 275.7 µg/mL; apiole 388.3 µg/mL), displayed mild anti-Aß1-42 fibrilization (DHC 26.6%) and good anti-oligomerization activity (>40% by dill-EA, carvone, and apiole). Such multifactorial neuroprotective displayed by dill and bioactives would help develop a safe, low-cost, and small-molecule drug for NDs.

Increased oligomeric TDP-43 in the plasma of Korean frontotemporal dementia patients with semantic dementia.

INTRODUCTION: Semantic dementia (SD) is a progressive neurodegenerative disease associated with impaired vocabulary that progresses to memory impairment. Post-mortem immunohistochemical analysis is the current reliable method of differentiating TDP-43 deposits in cortical tissue; no means of antemortem diagnosis exists in biofluids, let alone in plasma. METHODS: Here the multimer detection system (MDS) was used to quantify the oligomeric TDP-43 (o-TDP-43) concentrations in plasma of Korean SD patients (n = 16, 6 male, 10 female, ages 59-87). The o-TDP-43 concentrations were compared with the total TDP-43 (t-TDP-43) concentrations quantified through conventional enzyme-linked immunosorbent assay (ELISA). RESULTS AND DISCUSSION: Only MDS showed a significant increase in o-TDP-43 concentrations in the plasma of patients with SD compared to other neurodegenerative disorders and normal controls (p < 0.05). Based on these results, o-TDP-43 concentrations through the application of MDS may be a useful plasma biomarker in SD-FTD (frontotemporal dementia) diagnosis.

Presenilin-1 (PSEN1) Mutations: Clinical Phenotypes beyond Alzheimer's Disease.

Presenilin 1 (PSEN1) is a part of the gamma secretase complex with several interacting substrates, including amyloid precursor protein (APP), Notch, adhesion proteins and beta catenin. PSEN1 has been extensively studied in neurodegeneration, and more than 300 PSEN1 mutations have been discovered to date. In addition to the classical early onset Alzheimer's disease (EOAD) phenotypes, PSEN1 mutations were discovered in several atypical AD or non-AD phenotypes, such as frontotemporal dementia (FTD), Parkinson's disease (PD), dementia with Lewy bodies (DLB) or spastic paraparesis (SP). For example, Leu113Pro, Leu226Phe, Met233Leu and an Arg352 duplication were discovered in patients with FTD, while Pro436Gln, Arg278Gln and Pro284Leu mutations were also reported in patients with motor dysfunctions. Interestingly, PSEN1 mutations may also impact non-neurodegenerative phenotypes, including PSEN1 Pro242fs, which could cause acne inversa, while Asp333Gly was reported in a family with dilated cardiomyopathy. The phenotypic diversity suggests that PSEN1 may be responsible for atypical disease phenotypes or types of disease other than AD. Taken together, neurodegenerative diseases such as AD, PD, DLB and FTD may share several common hallmarks (cognitive and motor impairment, associated with abnormal protein aggregates). These findings suggested that PSEN1 may interact with risk modifiers, which may result in alternative disease phenotypes such as DLB or FTD phenotypes, or through less-dominant amyloid pathways. Next-generation sequencing and/or biomarker analysis may be essential in clearly differentiating the possible disease phenotypes and pathways associated with non-AD phenotypes.

Patient with PSEN1 Glu318Gly and Other Possible Disease Risk Mutations, Diagnosed with Early Onset Alzheimer's Disease.

In this manuscript, we introduced a French EOAD patient in Korea who carried the presenilin-1 (PSEN1) Glu318Gly mutations with four possible risk variants, including sortilin-related receptor 1 (SORL1) Glu270Lys, ATP-binding cassette subfamily A member 7 (ABCA7) Val1946Met, translocase of outer mitochondrial membrane 40 (TOMM40) Arg239Trp, and granulin (GRN) Ala505Gly. The patient started to present memory decline and behavioral dysfunction in his early 60s. His brain imaging presented amyloid deposits by positron emission tomography (PET-CT). The multimer detection system (MDS) screening test for plasma for amyloid oligomers was also positive, which supported the AD diagnosis. It was verified that PSEN1 Glu318Gly itself may not impact amyloid production. However, additional variants were found in other AD and non-AD risk genes, as follows: SORL1 Glu270Lys was suggested as a risk mutation for AD and could increase amyloid peptide production and impair endosome functions. ABCA7 Val1946Met was a novel variant that was predicted to be damaging. The GRN Ala505Gly was a variant with uncertain significance; however, it may reduce the granulin levels in the plasma of dementia patients. Pathway analysis revealed that PSEN1 Glu318Gly may work as a risk factor along with the SORL1 and ABCA7 variants since pathway analysis revealed that PSEN1 could directly interact with them through amyloid-related and lipid metabolism pathways. TOMM40 and PSEN1 could have common mechanisms through mitochondrial dysfunction. It may be possible that PSEN1 Glu318Gly and GRN Ala505Gly would impact disease by impairing immune-related pathways, including microglia and astrocyte development, or NFkB-related pathways. Taken together, the five risk factors may contribute to disease-related pathways, including amyloid and lipid metabolism, or impair immune mechanisms.

PSEN1 His214Asn Mutation in a Korean Patient with Familial EOAD and the Importance of Histidine-Tryptophan Interactions in TM-4 Stability.

A pathogenic mutation in presenilin-1 (PSEN1), His214Asn, was found in a male patient with memory decline at the age of 41 in Korea for the first time. The proband patient was associated with a positive family history from his father, paternal aunt, and paternal grandmother without genetic testing. He was diagnosed with early onset Alzheimer's disease (EOAD). PSEN1 His214Asn was initially reported in an Italian family, where the patient developed phenotypes similar to the current proband patient. Magnetic resonance imaging (MRI) scans revealed a mild hippocampal atrophy. The amyloid positron emission tomography (amyloid-PET) was positive, along with the positive test results of the increased amyloid ß (Aß) oligomerization tendency with blood. The PSEN1 His214 amino acid position plays a significant role in the gamma-secretase function, especially from three additional reported mutations in this residue: His214Asp, His214Tyr, and His214Arg. The structure prediction model revealed that PSEN1 protein His214 may interact with Trp215 of His-Trp cation-π interaction, and the mutations of His214 would destroy this interaction. The His-Trp cation-π interaction between His214 and Trp215 would play a crucial structural role in stabilizing the 4th transmembrane domain of PSEN1 protein, especially when aromatic residues were often reported in the membrane interface of the lipid-extracellular region of alpha helices or beta sheets. The His214Asn would alter the cleavage dynamics of gamma-secretase from the disappeared interactions between His214 and Trp215 inside of the helix, resulting in elevated amyloid production. Hence, the increased Aß was reflected in the increased Aß oligomerization tendency and the accumulations of Aß in the brain from amyloid-PET, leading to EOAD.

Double Mutations in a Patient with Early-Onset Alzheimer's Disease in Korea: An APP Val551Met and a PSEN2 His169Asn.

The etiology of early-onset Alzheimer's disease (EOAD) is associated with alterations in the production of amyloid beta (Aß) species caused by mutations in the APP, PSEN1, and PSEN2 genes. Mutations affect intra- or inter-molecular interactions and processes between the γ-secretase complex and amyloid precursor protein (APP), leading to the aberrant sequential cleavage of Aß species. A 64-year-old woman presented with progressive memory decline, mild right hippocampal atrophy, and a family history of Alzheimer's dementia (AD). Whole exome sequencing was performed to evaluate AD-related gene mutations, which were verified by Sanger sequencing. A mutation-caused structural alteration of APP was predicted using in silico prediction programs. Two AD-related mutations, in APP (rs761339914; c.G1651A; p.V551M) and PSEN2 (rs533813519; c.C505A; p.H169N), were identified. The APP Val551Met mutation in the E2 domain may influence APP homodimerization through changes in intramolecular interactions between adjacent amino acids, altering Aß production. The second mutation was PSEN2 His169Asn mutation, which was previously reported in five EOAD patients from Korea and China, with a relatively high frequency in the East Asian population. According to a previous report, the presenilin 2 protein was predicted to result in a major helical torsion by PSEN2 His169Asn mutation. Notably, the co-existence of APP Val551Met and PSEN2 His169Asn may induce a synergistic effect by both mutations. Future functional studies are needed to clarify the pathological effects of these double mutations.

Multi-Targeting Neuroprotective Effects of Syzygium aromaticum Bud Extracts and Their Key Phytocompounds against Neurodegenerative Diseases.

Alzheimer's disease (AD) is a neurodegenerative disease that causes a gradual loss of normal motor and cognitive function. The complex AD pathophysiology involves various factors such as oxidative stress, neuroinflammation, amyloid-beta (Aß) aggregation, disturbed neurotransmission, and apoptosis. The available drugs suffer from a range of side effects and are not able to cover different aspects of the disease. Therefore, finding a safer therapeutic approach that can affect multiple targets at a time is highly desirable. In the present study, the underlying neuroprotective mechanism of an important culinary spice, Syzygium aromaticum (Clove) extract, and major bioactive compounds were studied in hydrogen peroxide-induced oxidative stress in human neuroblastoma SH-SY5Y cell lines as a model. The extracts were subjected to GC-MS to identify important bioactive components. The extracts and key bio-actives reduced reactive oxygen species (ROS), restored mitochondrial membrane potential (MMP), and provided neuroprotection from H2O2-induced oxidative stress in cell-based assays due to the antioxidant action. They also reduced lipid peroxidation significantly and restored GSH content. Clove extracts have also displayed anti-acetylcholinesterase (AChE) activity, anti-glycation potential, and Aß aggregation/fibrilization inhibition. The multitarget neuroprotective approach displayed by Clove makes it a potential candidate for AD drug development.

Genetics of Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) and Role of Sacsin in Neurodegeneration.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is an early-onset neurodegenerative disease that was originally discovered in the population from the Charlevoix-Saguenay-Lac-Saint-Jean (CSLSJ) region in Quebec. Although the disease progression of ARSACS may start in early childhood, cases with later onset have also been observed. Spasticity and ataxia could be common phenotypes, and retinal optic nerve hypermyelination is detected in the majority of patients. Other symptoms, such as pes cavus, ataxia and limb deformities, are also frequently observed in affected individuals. More than 200 mutations have been discovered in the SACS gene around the world. Besides French Canadians, SACS genetics have been extensively studied in Tunisia or Japan. Recently, emerging studies discovered SACS mutations in several other countries. SACS mutations could be associated with pathogenicity either in the homozygous or compound heterozygous stages. Sacsin has been confirmed to be involved in chaperon activities, controlling the microtubule balance or cell migration. Additionally, sacsin may also play a crucial role in regulating the mitochondrial functions. Through these mechanisms, it may share common mechanisms with other neurodegenerative diseases. Further studies are needed to define the exact functions of sacsin. This review introduces the genetic mutations discovered in the SACS gene and discusses its pathomechanisms and its possible involvement in other neurodegenerative diseases.

Genetics, Functions, and Clinical Impact of Presenilin-1 (PSEN1) Gene.

Presenilin-1 (PSEN1) has been verified as an important causative factor for early onset Alzheimer's disease (EOAD). PSEN1 is a part of γ-secretase, and in addition to amyloid precursor protein (APP) cleavage, it can also affect other processes, such as Notch signaling, ß-cadherin processing, and calcium metabolism. Several motifs and residues have been identified in PSEN1, which may play a significant role in γ-secretase mechanisms, such as the WNF, GxGD, and PALP motifs. More than 300 mutations have been described in PSEN1; however, the clinical phenotypes related to these mutations may be diverse. In addition to classical EOAD, patients with PSEN1 mutations regularly present with atypical phenotypic symptoms, such as spasticity, seizures, and visual impairment. In vivo and in vitro studies were performed to verify the effect of PSEN1 mutations on EOAD. The pathogenic nature of PSEN1 mutations can be categorized according to the ACMG-AMP guidelines; however, some mutations could not be categorized because they were detected only in a single case, and their presence could not be confirmed in family members. Genetic modifiers, therefore, may play a critical role in the age of disease onset and clinical phenotypes of PSEN1 mutations. This review introduces the role of PSEN1 in γ-secretase, the clinical phenotypes related to its mutations, and possible significant residues of the protein.

PSEN2 Thr421Met Mutation in a Patient with Early Onset Alzheimer's Disease.

Presenilin-2 (PSEN2) mutation Thr421Met was identified from a 57-years old patient with early onset Alzheimer's disease (EOAD) for the first time in Korea. Previously, this mutation was discovered in an EOAD patient in Japan without a change on amyloid production from the cellular study. Both Korean and Japanese patients developed the disease in their 50s. Memory loss was prominent in both cases, but no additional clinical information was available on the Japanese patient. Magnetic resonance imaging (MRI) images of the Korean patient revealed asymmetric atrophies in both temporo-parietal lobes. In addition, amyloid positron emission tomography (PET) also revealed amyloid deposits in the gray matter of the temporo-parietal lobes asymmetrically. PSEN2 Thr421 was conserved among a majority of vertebrates (such as zebras, elephants, and giant pandas); hence, Thr421 could play an important role in its functions and any mutations could cause detrimental ramifications in its interactions. Interestingly, PSEN2 Thr421 could have homology with PSEN1 Thr440, as PSEN1 T440del mutations were reported from patients with AD or dementia with Lewy bodies. Hence, the changed amino acid from threonine to methionine of PSEN2 Thr421 could cause significant structural alterations in causing local protein dynamics, leading to its pathogenicity in EOAD. Lastly, PSEN2 Thr421Met may interact with other mutations in neurodegenerative disease related genes, which were found in the proband patient, such as ATP binding cassette subfamily A member 7 (ABCA7), Notch Receptor 3 (NOTCH3), or Leucine-rich repeat kinase 2 (LRRK2). These interactions of pathway networks among PSEN2 and other disease risk factors could be responsible for the disease phenotype through other pathways. For example, PSEN2 and ABCA7 may impact amyloid processing and reduce amyloid clearance. Interaction between PSEN2 and NOTCH3 variants may be associated with abnormal NOTCH signaling and a lower degree of neuroprotection. Along with LRRK2 variants, PSEN2 Thr421Met may impact neurodegeneration through Wnt related pathways. In the future, cellular studies of more than one mutation by CRISPR-Cas9 method along with biomarker profiles could be helpful to understand the complicated pathways.

Prion Mutations in Republic of Republic of Korea, China, and Japan.

Prion gene (PRNP) mutations are associated with diverse disease phenotypes, including familiar Creutzfeldt-Jakob Disease (CJD), Gerstmann-Sträussler-Scheinker disease (GSS), and fatal familial insomnia (FFI). Interestingly, PRNP mutations have been reported in patients diagnosed with Alzheimer's disease, dementia with Lewy bodies, Parkinson's disease, and frontotemporal dementia. In this review, we describe prion mutations in Asian countries, including Republic of Republic of Korea, China, and Japan. Clinical phenotypes and imaging data related to these mutations have also been introduced in detail. Several prion mutations are specific to Asians and have rarely been reported in countries outside Asia. For example, PRNP V180I and M232R, which are rare in other countries, are frequently detected in Republic of Korea and Japan. PRNP T188K is common in China, and E200K is significantly more common among Libyan Jews in Israel. The A117V mutation has not been detected in any Asian population, although it is commonly reported among European GSS patients. In addition, V210I or octapeptide insertion is common among European CJD patients, but relatively rare among Asian patients. The reason for these differences may be geographical or ethical isolation. In terms of clinical phenotypes, V180I, P102L, and E200K present diverse clinical symptoms with disease duration, which could be due to other genetic and environmental influences. For example, rs189305274 in the ACO1 gene may be associated with neuroprotective effects in cases of V180I mutation, leading to longer disease survival. Additional neuroprotective variants may be possible in cases featuring the E200K mutation, such as KLKB1, KARS, NRXN2, LAMA3, or CYP4X1. E219K has been suggested to modify the disease course in cases featuring the P102L mutation, as it may result in the absence of prion protein-positive plaques in tissue stained with Congo red. However, these studies analyzed only a few patients and may be too preliminary. The findings need to be verified in studies with larger sample sizes or in other populations. It would be interesting to probe additional genetic factors that cause disease progression or act as neuroprotective factors. Further studies are needed on genetic modifiers working with prions and alterations from mutations.

Identification of the Third Case of PSEN1 Tyr389His Variant in Early-Onset Alzheimer's Disease in Korea.

Amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) are associated with autosomal-dominant early-onset Alzheimer's disease (AD). Most mutations have been identified in the PSEN1 gene. We discovered a PSEN1 mutation (Tyr389His) in a Korean patient with early-onset AD who presented memory decline at 41 years of age followed by language, memory, and visuospatial dysfunctions. As this is the third such patient identified in Korea, this mutation may be involved in AD pathogenesis, suggesting that routine screening is necessary in this population. Altered intra-molecular interactions with the mutated amino acid may result in the destabilization of γ-secretase. In the future, a panel incorporating genes with relatively high-frequency rare variants, along with the APOE4 gene, may predict the onset of AD and facilitate customized treatment.

A Possible Pathogenic PSEN2 Gly56Ser Mutation in a Korean Patient with Early-Onset Alzheimer's Disease.

Early-onset Alzheimer's disease (EOAD) is characterized by the presence of neurological symptoms in patients with Alzheimer's disease (AD) before 65 years of age. Mutations in pathological genes, including amyloid protein precursor (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2), were associated with EOAD. Seventy-six mutations in PSEN2 have been found around the world, which could affect the activity of γ-secretase in amyloid beta processing. Here, a heterozygous PSEN2 point mutation from G to A nucleotide change at position 166 (codon 56; c.166G>A, Gly56Ser) was identified in a 64-year-old Korean female with AD with progressive cognitive memory impairment for the 4 years prior to the hospital visit. Hippocampal atrophy was observed from magnetic resonance imaging-based neuroimaging analyses. Temporal and parietal cortex hypometabolisms were identified using fluorodeoxyglucose positron emission tomography. This mutation was at the N-terminal portion of the presenilin 2 protein on the cytosolic side. Therefore, the serine substitution may have promoted AD pathogenesis by perturbing to the mutation region through altered phosphorylation of presenilin. In silico analysis revealed that the mutation altered protein bulkiness with increased hydrophilicity and reduced flexibility of the mutated region of the protein. Structural changes were likely caused by intramolecular interactions between serine and other residues, which may have affected APP processing. The functional study will clarify the pathogenicity of the mutation in the future.

SARS-CoV-2 (COVID-19): Beginning to Understand a New Virus.

Within the last two decades, several members of the Coronaviridae family demonstrated epidemic potential. In late 2019, an unnamed genetic relative, later named SARS-CoV-2 (COVID-19), erupted in the highly populous neighborhoods of Wuhan, China. Unchecked, COVID-19 spread rapidly among interconnected communities and related households before containment measures could be enacted. At present, the mortality rate of COVID-19 infection worldwide is 6.6%. In order to mitigate the number of infections, restrictions or recommendations on the number of people that can gather in a given area have been employed by governments worldwide. For governments to confidently lift these restrictions as well as counter a potential secondary wave of infections, alternative medications and diagnostic strategies against COVID-19 are urgently required. This review has focused on these issues.

Phytosterols: Potential Metabolic Modulators in Neurodegenerative Diseases.

Phytosterols constitute a class of natural products that are an important component of diet and have vast applications in foods, cosmetics, and herbal medicines. With many and diverse isolated structures in nature, they exhibit a broad range of biological and pharmacological activities. Among over 200 types of phytosterols, stigmasterol and ß-sitosterol were ubiquitous in many plant species, exhibiting important aspects of activities related to neurodegenerative diseases. Hence, this mini-review presented an overview of the reported studies on selected phytosterols related to neurodegenerative diseases. It covered the major phytosterols based on biosynthetic considerations, including other phytosterols with significant in vitro and in vivo biological activities.

A pathogenic PSEN1 Trp165Cys mutation associated with early-onset Alzheimer's disease.

BACKGROUND: Presenilin-1 (PSEN1) is one of the causative genes for early onset Alzheimer's disease (EOAD). Recently, emerging studies reported several novel PSEN1 mutations among Asian. We describe a male with EOAD had a pathogenic PSEN1 mutation. CASE PRESENTATION: A 53-year-old male presented with memory decline, followed by difficulty in finding ways. Patient had positive family history, since his mother and one of his brother was also affected with dementia. Brain magnetic resonance imaging (MRI) scan showed mild degree of atrophy of bilateral hippocampus and parietal lobe. 18F-Florbetaben-PET (FBB-PET) revealed increased amyloid deposition in bilateral frontal, parietal, temporal lobe and precuneus. Whole exome analysis revealed a heterozygous, probably pathogenic PSEN1 (c.695G > T, p.W165C) mutation. Interestingly, Trp165Cys mutation is located in trans membrane (TM)-III region, which is conserved between PSEN1/PSEN2. In vitro studies revealed that PSEN1 Trp165Cys could result in disturbances in amyloid metabolism. This prediction was confirmed by structure predictions and previous in vitro studies that the p.Trp165Cys could result in decreased Aß42/Aß40 ratios. CONCLUSION: We report a case of EOAD having a pathogenic PSEN1 (Trp165Cys) confirmed with in silico and in vitro predictions.

Epitope Mapping Immunoassay Analysis of the Interaction between ß-Amyloid and Fibrinogen.

The vast majority of patients with Alzheimer's disease (AD) suffer from impaired cerebral circulation. Substantial evidence indicates that fibrinogen (Fbg) and fibrin clot formation play an important role in this circulatory dysfunction in AD. Fbg interacts with ß-amyloid (1-42) (Aß), forming plasmin-resistant abnormal blood clots, and increased fibrin deposition has been discovered in the brains of AD patients and mouse models. In this study, biochemical approaches and the epitope mapping immunoassay were employed to characterize binding epitopes within the Fbg and complementary epitopes in Aß. We discovered the Aß5⁻25 peptide as the most critical region for the interaction, which can be inhibited by specific monoclonal and polyclonal antibodies against the central region of Aß. Aß binding to Fbg may block plasmin-mediated fibrin cleavage at this site, resulting in the generation of increased levels of plasmin-resistant fibrin degradation fragments. Our study elucidates the Aß⁻Fbg interaction that may involve the mechanism by which Aß⁻Fbg binding delays fibrinolysis by plasmin, providing valuable information in the development of therapeutic approaches for AD.

Potential Fluid Biomarkers for the Diagnosis of Mild Cognitive Impairment.

Mild cognitive impairment (MCI) is characterized by a level of cognitive impairment that is lower than normal for a person's age, but a higher function than that that observed in a demented person. MCI represents a transitional state between normal aging and dementia disorders, especially Alzheimer's disease (AD). Much effort has been made towards determining the prognosis of a person with MCI who will convert to AD. It is now clear that cerebrospinal fluid (CSF) levels of Aß40, Aß42, total tau and phosphorylated tau are useful for predicting the risk of progression from MCI to AD. This review highlights the advantages of the current blood-based biomarkers in MCI, and discusses some of these challenges, with an emphasis on recent studies to provide an overview of the current state of MCI.