Pharmacogenomics in Alzheimer's disease

Recent Advances in the Treatment and Management of Alzheimer's Disease: A Precision Medicine Perspective

About 60% to 70% of people with dementia have Alzheimer's Disease (AD), a neurodegenerative illness. One reason for this disorder is the misfolding of naturally occurring proteins in the human brain, specifically β-amyloid (Aβ) and tau. Certain diagnostic imaging techniques, such as amyloid PET imaging, tau PET imaging, Magnetic Resonance Imaging (MRI), Computerized Tomography (CT), and others, can detect biomarkers in blood, plasma, and cerebral spinal fluids, like an increased level of β-amyloid, plaques, and tangles. In order to create new pharmacotherapeutics for Alzheimer's disease, researchers must have a thorough and detailed knowledge of amyloid beta misfolding and other related aspects. Donepezil, rivastigmine, galantamine, and other acetylcholinesterase inhibitors are among the medications now used to treat Alzheimer's disease. Another medication that can temporarily alleviate dementia symptoms is memantine, which blocks the N-methyl-D-aspartate (NMDA) receptor. However, it is not able to halt or reverse the progression of the disease. Medication now on the market can only halt its advancement, not reverse it. Interventions to alleviate behavioral and psychological symptoms, exhibit anti- neuroinflammation and anti-tau effects, induce neurotransmitter alteration and cognitive enhancement, and provide other targets have recently been developed. For some Alzheimer's patients, the FDA-approved monoclonal antibody, aducanumab, is an option; for others, phase 3 clinical studies are underway for drugs, like lecanemab and donanemab, which have demonstrated potential in eliminating amyloid protein. However, additional study is required to identify and address these limitations in order to reduce the likelihood of side effects and maximize the therapeutic efficacy.

Pharmacogenetics of anxiety and depression in Alzheimer's disease

Anxiety and depression coexist with cognitive impairment in Alzheimer's disease along with other concomitant disorders (>60%), which require multipurpose treatments. Polypharmaceutical regimens cause drug-drug interactions and adverse drug reactions, potentially avoidable in number and severity with the implementation of pharmacogenetic procedures. The accumulation of defective variants (>30 genes per patient in more than 50% of cases) in pharmagenes (pathogenic, mechanistic, metabolic, transporter, pleiotropic) influences the therapeutic response to antidementia, antidepressant and anxiolytic drugs in polyvalent regimens. APOE, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4, CYP3A5, CYP4F2, COMT, MAOB, CHAT, GSTP1, NAT2, SLC30A8, SLCO1B1, ADRA2A, ADRB2, BCHE, GABRA1, HMGCR, HTR2C, IFNL3, NBEA, UGT1A1, ABCB1, ABCC2, ABCG2, SLC6A2, SLC6A3, SLC6A4, MTHFR and OPRM1 variants affect anxiety and depression in Alzheimer's disease.

Dementia Prevention in Clinical Practice

Over 55 million people globally are living with dementia and, by 2050, this number is projected to increase to 131 million. This poses immeasurable challenges for patients and their families and a significant threat to domestic and global economies. Given this public health crisis and disappointing results from disease-modifying trials, there has been a recent shift in focus toward primary and secondary prevention strategies. Approximately 40% of Alzheimer's disease (AD) cases, which is the most common form of dementia, may be prevented or at least delayed. Success of risk reduction studies through addressing modifiable risk factors, in addition to the failure of most drug trials, lends support for personalized multidomain interventions rather than a "one-size-fits-all" approach. Evolving evidence supports early intervention in at-risk patients using individualized interventions directed at modifiable risk factors. Comprehensive risk stratification can be informed by emerging principals of precision medicine, and include expanded clinical and family history, anthropometric measurements, blood biomarkers, neurocognitive evaluation, and genetic information. Risk stratification is key in differentiating subtypes of dementia and identifies targetable areas for intervention. This article reviews a clinical approach toward dementia risk stratification and evidence-based prevention strategies, with a primary focus on AD.

Pharmacogenomics of Alzheimer's Disease: Novel Strategies for Drug Utilization and Development

Alzheimer's disease (AD) is a priority health problem in developed countries with a high cost to society. Approximately 20% of direct costs are associated with pharmacological treatment. Over 90% of patients require multifactorial treatments, with risk of adverse drug reactions (ADRs) and drug-drug interactions (DDIs) for the treatment of concomitant diseases such as hypertension (>25%), obesity (>70%), diabetes mellitus type 2 (>25%), hypercholesterolemia (40%), hypertriglyceridemia (20%), metabolic syndrome (20%), hepatobiliary disorder (15%), endocrine/metabolic disorders (>20%), cardiovascular disorder (40%), cerebrovascular disorder (60-90%), neuropsychiatric disorders (60-90%), and cancer (10%).For the past decades, pharmacological studies in search of potential treatments for AD focused on the following categories: neurotransmitter enhancers (11.38%), multitarget drugs (2.45%), anti-amyloid agents (13.30%), anti-tau agents (2.03%), natural products and derivatives (25.58%), novel synthetic drugs (8.13%), novel targets (5.66%), repository drugs (11.77%), anti-inflammatory drugs (1.20%), neuroprotective peptides (1.25%), stem cell therapy (1.85%), nanocarriers/nanotherapeutics (1.52%), and other compounds (<1%).Pharmacogenetic studies have shown that the therapeutic response to drugs in AD is genotype-specific in close association with the gene clusters that constitute the pharmacogenetic machinery (pathogenic, mechanistic, metabolic, transporter, pleiotropic genes) under the regulatory control of epigenetic mechanisms (DNA methylation, histone/chromatin remodeling, microRNA regulation). Most AD patients (>60%) are carriers of over ten pathogenic genes. The genes that most frequently (>50%) accumulate pathogenic variants in the same AD case are A2M (54.38%), ACE (78.94%), BIN1 (57.89%), CLU (63.15%), CPZ (63.15%), LHFPL6 (52.63%), MS4A4E (50.87%), MS4A6A (63.15%), PICALM (54.38%), PRNP (80.7059), and PSEN1 (77.19%). There is also an accumulation of 15 to 26 defective pharmagenes in approximately 85% of AD patients. About 50% of AD patients are carriers of at least 20 mutant pharmagenes, and over 80% are deficient metabolizers for the most common drugs, which are metabolized via the CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 enzymes.The implementation of pharmacogenetics can help optimize drug development and the limited therapeutic resources available to treat AD, and personalize the use of anti-dementia drugs in combination with other medications for the treatment of concomitant disorders.

Epigenetic Biomarkers as Diagnostic Tools for Neurodegenerative Disorders

Epigenetics is the study of heritable changes in gene expression that occur without alterations to the DNA sequence, linking the genome to its surroundings. The accumulation of epigenetic alterations over the lifespan may contribute to neurodegeneration. The aim of the present study was to identify epigenetic biomarkers for improving diagnostic efficacy in patients with neurodegenerative diseases. We analyzed global DNA methylation, chromatin remodeling/histone modifications, sirtuin (SIRT) expression and activity, and the expression of several important neurodegeneration-related genes. DNA methylation, SIRT expression and activity and neuregulin 1 (NRG1), microtubule-associated protein tau (MAPT) and brain-derived neurotrophic factor (BDNF) expression were reduced in buffy coat samples from patients with neurodegenerative disorders. Our data suggest that these epigenetic biomarkers may be useful in clinical practical for the diagnosis, surveillance, and prognosis of disease activity in patients with neurodegenerative diseases.

Disparities in Alzheimer Disease and Mild Cognitive Impairment Among Native Hawaiians and Pacific Islanders

BACKGROUND

Previous studies of racial differences in Alzheimer disease (AD) presentation have not included Native Hawaiians and Pacific Islanders (NHPI).

OBJECTIVE

To explore the presentation of AD and mild cognitive impairment (MCI) in NHPI.

METHOD

We conducted a retrospective review of patient records from Hawaii with a diagnosis of unspecified AD or MCI from September 2000 to September 2019. Variables of interest included age at diagnosis, gender, race, marital status, insurance, comorbidities, and scores on the Mini-Mental State Examination (MMSE) or the Montreal Cognitive Assessment (MoCA).

RESULTS

We reviewed the medical records of 598 patients, including 224 Asians, 202 Whites, 87 NHPI, and 85 Other. AD was more dominant than MCI across all of the groups, with the highest percentage in NHPI. Among the mean ages of diagnosis, NHPI were the youngest. Across all groups, a higher proportion of women than men had AD, with the highest female prevalence among NHPI. Hypertension, hyperlipidemia, and type II diabetes were highest among NHPI compared with the other groups. Of individuals with MMSE/MoCA scores, there were significant variations in scores by racial group. The mean MMSE/MoCA score was highest among Whites and lowest among NHPI.

CONCLUSION

Compared with other racial groups, NHPI have a higher proportion of AD than MCI at diagnosis, are diagnosed at a younger age, have a higher female prevalence, have more comorbidities that may contribute to AD/MCI onset, and present with lower MMSE scores.

Influence of Pathogenic and Metabolic Genes on the Pharmacogenetics of Mood Disorders in Alzheimer's Disease

Background: Mood disorders represent a risk factor for dementia and are present in over 60% of cases with Alzheimer’s disease (AD). More than 80% variability in drug pharmacokinetics and pharmacodynamics is associated with pharmacogenetics. Methods: Anxiety and depression symptoms were assessed in 1006 patients with dementia (591 females, 415 males) and the influence of pathogenic (APOE) and metabolic (CYP2D6, CYP2C19, and CYP2C9) gene variants on the therapeutic outcome were analyzed after treatment with a multifactorial regime in a natural setting. Results and Conclusions: (i) Biochemical, hematological, and metabolic differences may contribute to changes in drug efficacy and safety; (ii) anxiety and depression are more frequent and severe in females than males; (iii) both females and males respond similarly to treatment, showing significant improvements in anxiety and depression; (iv) APOE-3 carriers are the best responders and APOE-4 carriers tend to be the worst responders to conventional treatments; and (v) among CYP2D6, CYP2C19, and CYP2C9 genophenotypes, normal metabolizers (NMs) and intermediate metabolizers (IMs) are significantly better responders than poor metabolizers (PMs) and ultra-rapid metabolizers (UMs) to therapeutic interventions that modify anxiety and depression phenotypes in dementia. APOE-4 carriers and CYP-related PMs and UMs deserve special attention for their vulnerability and poor response to current treatments.

Pharmacogenetic considerations when prescribing cholinesterase inhibitors for the treatment of Alzheimer's disease

INTRODUCTION

Cholinergic dysfunction, demonstrated in the late 1970s and early 1980s, led to the introduction of acetylcholinesterase inhibitors (AChEIs) in 1993 (Tacrine) to enhance cholinergic neurotransmission as the first line of treatment against Alzheimer's disease (AD). The new generation of AChEIs, represented by Donepezil (1996), Galantamine (2001) and Rivastigmine (2002), is the only treatment for AD to date, together with Memantine (2003). AChEIs are not devoid of side-effects and their cost-effectiveness is limited. An option to optimize the correct use of AChEIs is the implementation of pharmacogenetics (PGx) in the clinical practice.

AREAS COVERED

(i) The cholinergic system in AD, (ii) principles of AD PGx, (iii) PGx of Donepezil, Galantamine, Rivastigmine, Huperzine and other treatments, and (iv) practical recommendations.

EXPERT OPINION

The most relevant genes influencing AChEI efficacy and safety are APOE and CYPs. APOE-4 carriers are the worst responders to AChEIs. With the exception of Rivastigmine (UGT2B7, BCHE-K), the other AChEIs are primarily metabolized via CYP2D6, CYP3A4, and UGT enzymes, with involvement of ABC transporters and cholinergic genes (CHAT, ACHE, BCHE, SLC5A7, SLC18A3, CHRNA7) in most ethnic groups. Defective variants may affect the clinical response to AChEIs. PGx geno-phenotyping is highly recommended prior to treatment.

Gene Polymorphisms Affecting the Pharmacokinetics and Pharmacodynamics of Donepezil Efficacy

Donepezil (DNP) is the first-line drug used for Alzheimer's disease (AD). However, the therapeutic response rate of patients to DNP varies from 20 to 60%. The main reason for the large differences in the clinical efficacy of DNP therapy is genetic factors, some of which affect pharmacokinetics (PK), while others affect pharmacodynamics (PD). Thus, much emphasis has been placed on the investigation of an association between PK- and PD-related gene polymorphisms and therapeutic response to DNP, but a consistent view does not yet exist. In this review, we summarize recent findings regarding genetic factors influencing the clinical efficacy of DNP, including substantial differences in individual responses as a consequence of polymorphisms in Cytochrome P450 (CYP) 2D6, CY3A4, CY3A5, APOE, ABCA1, ABCB1, ESR1, BCHE, PON-1, CHRNA7, and CHAT. We also discuss possible strategies for the evaluation of the clinical efficacy of DNP, with a specific focus on possible biomarkers of PK/PD parameters, and provide perspectives and limitations within the field, which will also be beneficial for understanding the multiple mechanisms of DNP therapy in AD.

Pharmacogenomics of Cognitive Dysfunction and Neuropsychiatric Disorders in Dementia

Symptomatic interventions for patients with dementia involve anti-dementia drugs to improve cognition, psychotropic drugs for the treatment of behavioral disorders (BDs), and different categories of drugs for concomitant disorders. Demented patients may take >6-10 drugs/day with the consequent risk for drug-drug interactions and adverse drug reactions (ADRs >80%) which accelerate cognitive decline. The pharmacoepigenetic machinery is integrated by pathogenic, mechanistic, metabolic, transporter, and pleiotropic genes redundantly and promiscuously regulated by epigenetic mechanisms. CYP2D6, CYP2C9, CYP2C19, and CYP3A4/5 geno-phenotypes are involved in the metabolism of over 90% of drugs currently used in patients with dementia, and only 20% of the population is an extensive metabolizer for this tetragenic cluster. ADRs associated with anti-dementia drugs, antipsychotics, antidepressants, anxiolytics, hypnotics, sedatives, and antiepileptic drugs can be minimized by means of pharmacogenetic screening prior to treatment. These drugs are substrates, inhibitors, or inducers of 58, 37, and 42 enzyme/protein gene products, respectively, and are transported by 40 different protein transporters. APOE is the reference gene in most pharmacogenetic studies. APOE-3 carriers are the best responders and APOE-4 carriers are the worst responders; likewise, CYP2D6-normal metabolizers are the best responders and CYP2D6-poor metabolizers are the worst responders. The incorporation of pharmacogenomic strategies for a personalized treatment in dementia is an effective option to optimize limited therapeutic resources and to reduce unwanted side-effects.

Pharmacogenetics in the clinical analysis laboratory: clinical practice, research, and drug development pipeline

Introduction: Over the last decade, the spread of next-generation sequencing technology along with the rising cost in health management in national health systems has led to widespread use/abuse of pharmacogenetic tests (PGx) in the practice of many clinical disciplines. However, given their clinical significance, it is important to standardize these tests for having an interaction with the clinical analysis laboratory (CAL), in which a PGx service can meet these requirements. Areas covered: A diagnostic test must meet the criteria of reproducibility and validity for its utility in the clinical routine. This present review mainly describes the utility of introducing PGx tests in the CAL routine to produce correct results useful for setting up personalized drug treatments. Expert opinion: With a PGx service, CALs can provide the right tool to help clinicians to make better choices about different categories of drugs and their dosage and to manage the economic impact both in hospital-based settings and in National Health Services, throughout electronic health records. Advances in PGx also allow a new approach for pharmaceutical companies in order to improve drug development and clinical trials. As a result, CALs can achieve a powerful source of epidemiological, clinical, and research findings from PGx tests.

Sirtuins in Alzheimer's Disease: SIRT2-Related GenoPhenotypes and Implications for PharmacoEpiGenetics

Sirtuins (SIRT1-7) are NAD⁺-dependent protein deacetylases/ADP ribosyltransferases with important roles in chromatin silencing, cell cycle regulation, cellular differentiation, cellular stress response, metabolism and aging. Sirtuins are components of the epigenetic machinery, which is disturbed in Alzheimer’s disease (AD), contributing to AD pathogenesis. There is an association between the SIRT2-C/T genotype (rs10410544) (50.92%) and AD susceptibility in the APOEε4-negative population (SIRT2-C/C, 34.72%; SIRT2-T/T 14.36%). The integration of SIRT2 and APOE variants in bigenic clusters yields 18 haplotypes. The 5 most frequent bigenic genotypes in AD are 33CT (27.81%), 33CC (21.36%), 34CT (15.29%), 34CC (9.76%) and 33TT (7.18%). There is an accumulation of APOE-3/4 and APOE-4/4 carriers in SIRT2-T/T > SIRT2-C/T > SIRT2-C/C carriers, and also of SIRT2-T/T and SIRT2-C/T carriers in patients who harbor the APOE-4/4 genotype. SIRT2 variants influence biochemical, hematological, metabolic and cardiovascular phenotypes, and modestly affect the pharmacoepigenetic outcome in AD. SIRT2-C/T carriers are the best responders, SIRT2-T/T carriers show an intermediate pattern, and SIRT2-C/C carriers are the worst responders to a multifactorial treatment. In APOE-SIRT2 bigenic clusters, 33CC carriers respond better than 33TT and 34CT carriers, whereas 24CC and 44CC carriers behave as the worst responders. CYP2D6 extensive metabolizers (EM) are the best responders, poor metabolizers (PM) are the worst responders, and ultra-rapid metabolizers (UM) tend to be better responders that intermediate metabolizers (IM). In association with CYP2D6 genophenotypes, SIRT2-C/T-EMs are the best responders. Some Sirtuin modulators might be potential candidates for AD treatment.

Pharmacoepigenomic Interventions as Novel Potential Treatments for Alzheimer's and Parkinson's Diseases

Cerebrovascular and neurodegenerative disorders affect one billion people around the world and result from a combination of genomic, epigenomic, metabolic, and environmental factors. Diagnosis at late stages of disease progression, limited knowledge of gene biomarkers and molecular mechanisms of the pathology, and conventional compounds based on symptomatic rather than mechanistic features, determine the lack of success of current treatments, including current FDA-approved conventional drugs. The epigenetic approach opens new avenues for the detection of early presymptomatic pathological events that would allow the implementation of novel strategies in order to stop or delay the pathological process. The reversibility and potential restoring of epigenetic aberrations along with their potential use as targets for pharmacological and dietary interventions sited the use of epidrugs as potential novel candidates for successful treatments of multifactorial disorders involving neurodegeneration. This manuscript includes a description of the most relevant epigenetic mechanisms involved in the most prevalent neurodegenerative disorders worldwide, as well as the main potential epigenetic-based compounds under investigation for treatment of those disorders and their limitations.

OxLDL plasma levels in patients with Alzheimer's disease

OBJECTIVE

The objective of this study was to characterize the conventional lipid profile, oxLDL levels and ApoE polymorphism in patients with Alzheimer's disease (AD) and in elderly individuals without cognitive impairment.

METHODS

Eighty elderly individuals were selected and the levels of oxLDL were determined using the ELISA kit, and ApoE gene polymorphism was investigated using polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Significantly reduced levels of oxLDL were observed in patients with AD compared to the control group. A higher frequency of the ApoE ε4 allele was observed in patients with AD compared to controls. No difference was observed for total cholesterol, HDL-C, and LDL-C levels between the two groups, while triglyceride levels were higher in controls compared with patients with AD.

CONCLUSION

The data analyzed together did not reveal significant differences in lipid profiles, including oxLDL levels. However, the importance of lipid changes in the genesis of the disease cannot be ruled out. Nevertheless, the ApoE ε4 allele was significantly more frequent in patients with Alzheimer's dementia in agreement with previous findings in the literature, but this genetic component did not change the levels of oxLDL.

Population-based Study of Risk Polymorphisms Associated with Vascular Disorders and Dementia

Introduction:

Cardiovascular and neurodegenerative disorders are among the major causes of mortality in the developed countries. Population studies evaluate the genetic risk, i.e. the probability of an individual carrying a specific disease-associated polymorphism. Identification of risk polymorphisms is essential for an accurate diagnosis or prognosis of a number of pathologies.

Aims:

The aim of this study was to characterize the influence of risk polymorphisms associated with lipid metabolism, hypertension, thrombosis, and dementia, in a large population of Spanish individuals affected by a variety of brain and vascular disorders as well as metabolic syndrome.

Material & Method:

We performed a cross-sectional study on 4415 individuals from a widespread regional distribution in Spain (48.15% males and 51.85% females), with mental, neurodegenerative, cerebrovascular, and metabolic disorders. We evaluated polymorphisms in 20 genes involved in obesity, vascular and cardiovascular risk, and dementia in our population and compared it with representative Spanish and European populations. Risk polymorphisms in ACE, AGT(235), IL6(573), PSEN1, and APOE (specially the APOE-ε4 allele) are representative of our population as compared to the reference data of Spanish and European individuals.

Conclusion:

The significantly higher distribution of risk polymorphisms in PSEN1 and APOE-ε4 is characteristic of a representative number of patients with Alzheimer’s disease; whereas polymorphisms in ACE, AGT(235), and IL6(573), are most probably related with the high number of patients with metabolic syndrome or cerebrovascular damage.

Translation of Pre-Clinical Studies into Successful Clinical Trials for Alzheimer's Disease: What are the Roadblocks and How Can They Be Overcome?

Preclinical studies are essential for translation to disease treatments and effective use in clinical practice. An undue emphasis on single approaches to Alzheimer's disease (AD) appears to have retarded the pace of translation in the field, and there is much frustration in the public about the lack of an effective treatment. We critically reviewed past literature (1990-2014), analyzed numerous data, and discussed key issues at a consensus conference on Brain Ageing and Dementia to identify and overcome roadblocks in studies intended for translation. We highlight various factors that influence the translation of preclinical research and highlight specific preclinical strategies that have failed to demonstrate efficacy in clinical trials. The field has been hindered by the domination of the amyloid hypothesis in AD pathogenesis while the causative pathways in disease pathology are widely considered to be multifactorial. Understanding the causative events and mechanisms in the pathogenesis are equally important for translation. Greater efforts are necessary to fill in the gaps and overcome a variety of confounds in the generation, study design, testing, and evaluation of animal models and the application to future novel anti-dementia drug trials. A greater variety of potential disease mechanisms must be entertained to enhance progress.

Pharmacogenetic considerations in the treatment of Alzheimer's disease

The practical pharmacogenetics of Alzheimer's disease (AD) is circumscribed to acetylcholinesterase inhibitors (AChEIs) and memantine. However, pharmacogenetic procedures should be applied to novel strategies in AD therapeutics including: novel AChEIs and neurotransmitter regulators, anti-Aβ treatments, anti-tau treatments, pleiotropic products, epigenetic drugs and combination therapies. Genes involved in the pharmacogenetic network are under the influence of the epigenetic machinery which regulates gene expression transcriptionally and post-transcriptionally, configuring the fundamentals of pharmacoepigenomics. Over 60% of AD patients present concomitant pathologies demanding additional treatments which increase the likelihood of drug-drug interactions. Lipid metabolism dysfunction is a pathogenic mechanism inherent to AD neurodegeneration. The therapeutic response to hypolipidemic compounds is influenced by the APOE and CYP genotypes. The development of novel compounds and the use of combination/multifactorial treatments require the implantation of pharmacogenomic procedures for the avoidance of ADRs and the optimization of therapeutics.

Cognitive Results of CANTAB Tests and Their Change Due to the First Dose of Donepezil May Predict Treatment Efficacy in Alzheimer Disease

Background

Ability to predict the efficacy of treatment in Alzheimer disease (AD) may be very useful in clinical practice. Cognitive predictors should be investigated alongside with the demographic, genetic, and other predictors of treatment efficacy. The aim of this study was to establish whether the baseline measures of CANTAB tests and their changes due to the first donepezil dose are able to predict the efficacy of treatment after 4 months of therapy. We also compared the predictive value of cognitive, clinical, and demographic predictors of treatment efficacy in AD.

Material/Methods

Seventy-two AD patients (62 treatment-naïve and 10 donepezil-treated) and 30 controls were enrolled in this prospective, randomized, rater-blinded, follow-up study. Treatment-naïve AD patients were randomized to 2 groups to take the first donepezil dose after the first or second CANTAB testing, separated by 4 hours. Follow-up Test 3 was performed 4 months after the initial assessment.

Results

The groups were similar in age, education, gender, Hachinski index, and depression. General Regression Models (GRM) have shown that cognitive changes after the first dose of donepezil in PAL (t-values for regression coefficients from 3.43 to 6.44), PRMd (t=4.33), SWM (t=5.85) test scores, and baseline results of PAL (t=2.57–2.86), PRM (t=3.08), and CRT (t=3.42) tests were significant predictors of long-term donepezil efficacy in AD (p<0.05).

Conclusions

The cognitive changes produced by the first donepezil dose in CANTAB PAL, PRM, and SWM test measures are able to predict the long-term efficacy of donepezil in AD. Baseline PAL, PRM, and CRT test results were significant predictors.

Cortisol, HDL-c, VLDL-c, and APOE Polymorphisms as Laboratorial Parameters Associated to Cognitive Impairment No Dementia (CIND) and Dementia

BACKGROUND

Population aging is a global phenomenon whose main consequence is the increase of chronic degenerative diseases, including dementia. The aim of this case-control study was to evaluate the laboratorial parameters lipid profile, cortisol, and apolipoprotein E (APOE) gene genotype, comparing cognitively healthy controls and subjects with cognitive impairment no dementia (CIND) and dementia in a group of elderly people.

METHODS

Three hundred and nine individuals enrolled in the Pietà Study (Brazil) were divided into three groups: control (n = 158), CIND (n = 92), and dementia (n = 59). Participants were interviewed, went through examination, and had blood samples taken.

RESULTS

Age and APOE showed significant differences among the groups, while sex and lipid profile did not. According to multivariate regression logistic analyses, higher cortisol levels, lower high-density lipoprotein (HDL-c) and very low-density lipoprotein (VLDL-c), presence of ε4 allele of APOE, and aging were associated with CIND and dementia.

CONCLUSION

These laboratorial parameters are risk factors associated to CIND and dementia in the elderly people and should be investigated in order to develop strategies to prevent or delay the onset of dementia in the oldest-old populations.

Pharmacogenetic Study on the Impact of Rivastigmine Concerning Genetic Variants of A2M and IL-6 Genes on Iranian Alzheimer's Patients

Alzheimer's disease (AD) is a polygenic and multifactorial disease with a complex inheritance caused by the formation of amyloid plaques and neurofibrillary tangles in the brain. Increasing evidence indicates that many genes including interleukin-6 (IL-6) and alpha 2-macroglobulin (A2M) may contribute to the pathogenesis of AD. The A2M gene encodes α2-macroglobulin which specifically binds with the beta-amyloid peptides and prevents fibril formation. Protein of the IL-6 gene linked to beta-amyloid (βA) aggregation was detected in βA plaques in the brain of AD patients. The aim of the present study is to investigate the relationship of the IL-6 and A2M gene polymorphisms with AD and also the impact of rivastigmine on AD patients regarding their genotypes on IL-6 and A2M genes in 150 Iranian AD patients under rivastigmine therapy and 150 matched healthy controls. The results indicated that IL-6 G and C alleles had significant positive and negative association with AD, respectively, (P = 0.0001, relative risks (RR) = 1.39) and frequency of AD patients carrying IL-6 GG genotype was significantly in higher proportion in familial Alzheimer's disease (FAD) patients compared to controls (P = 0.02, RR = 2.25), and the IL-6 CC genotype was significantly protective against AD (P = 0.0003, RR = 0.65). Genotype analysis of A2M gene showed a significant positive correlation between A2M AA genotype and the AD patients (sporadic Alzheimer's disease (SAD) and FAD) (P = 0.001, RR = 1.56), proposing it as a possible risk factor for AD. Drug response from pharmacogenetic viewpoint after 3-year follow-up of AD patients and Clinical Dementia Rating (CDR) analysis demonstrated that AD patients carrying bigenic genotype IL-6 CC-A2M AG (ΔCDR = 4.5) and male patients with IL-6 CC genotype (ΔCDR = 3.83) provided the best response and the A2M GG genotype (ΔCDR = 7.97) and bigenic genotype IL-6 GG-A2M GG (ΔCDR = 8.5) conferred the worst response to the rivastigmine, suggesting likely involvement of genotype-specific response to rivastigmine therapy in AD patients. The results also propose that in view of the fact that C and G alleles created by nucleotide changes in the promoter region of IL-6 gene and this may affect the expression of the IL-6 gene and, hence, susceptible and protective role of GG and CC genotype in AD might be caused by higher and lower expression of IL-6 cytokine, respectively.

Apolipoprotein E ε-4 as a genetic determinant of Alzheimer's disease heterogeneity

Alzheimer's disease (AD) displays a high degree of heterogeneity in terms of its etiology, presentation, prognosis, and treatment response. This can partly be explained by high-penetrance mutations in the amyloid precursor protein, presenilin 1 and presenilin 2 genes causing amyloid beta aggregation, which is a major pathogenic mechanism in the development of early-onset AD in a small subgroup of patients. Late-onset AD is considered a polygenic disorder in which cumulative risk resulting from interaction with modifiable environmental risk factors may be responsible for the majority of cases. The ε-4 allele of the apolipoprotein E (APOE) gene has emerged as the most significant genetic risk factor for late-onset AD, influencing nearly every pathogenic domain affected in AD. It is a major risk factor for cerebral amyloid angiopathy, recognized as a common pathological finding in an AD subtype associated with white matter dysfunction. The APOE ε-4 allele is also a known risk factor for ischemic stroke, which can result in vascular dementia or contribute to subcortical vascular dysfunction. In this review, we evaluate the clinical relevance of APOE genotyping in relation to cholesterol metabolism and available evidence on risk reduction strategies applicable to AD.

Opportunities in pharmacogenomics for the treatment of Alzheimer's disease

ABSTRACT 

In Alzheimer's disease (AD), approximately 10–20% of direct costs are associated with pharmacological treatment. Pharmacogenomics account for 30–90% variability in pharmacokinetics and pharmacodynamics. Genes potentially involved in the pharmacogenomics outcome include pathogenic, mechanistic, metabolic, transporter and pleiotropic genes. Over 75% of the Caucasian population is defective for the CYP2D6+2C9+2C19 cluster. Polymorphic variants in the APOE-TOMM40 region influence AD pharmacogenomics. APOE-4 carriers are the worst responders and APOE-3 carriers are the best responders to conventional treatments. TOMM40 poly T-S/S carriers are the best responders, VL/VL and S/VL carriers are intermediate responders and L/L carriers are the worst responders. The haplotype 4/4-L/L is probably responsible for early onset of the disease, a faster cognitive decline and a poor response to different treatments.

A comparative evaluation of a novel vaccine in APP/PS1 mouse models of Alzheimer's disease

Immunization against amyloid-beta-peptide (Aβ) has been widely investigated as a potential immunotherapeutic approach for Alzheimer's disease (AD). With the aim of developing an active immunogenic vaccine without need of coadjuvant modification for human trials and therefore avoiding such side effects, we designed the Aβ_1–42 vaccine (EB101), delivered in a liposomal matrix, that based on our previous studies significantly prevents and reverses the AD neuropathology, clearing Aβ plaques while markedly reducing neuronal degeneration, behavioral deficits, and minimizing neuroinflammation in APP/PS1 transgenic mice. Here, the efficacy of our immunogenic vaccine EB101 was compared with the original immunization vaccine cocktail Aβ₄₂ + CFA/IFA (Freund's adjuvant), in order to characterize the effect of sphingosine-1-phosphate (S1P) in the immunotherapeutic response. Quantitative analysis of amyloid burden showed a notable decrease in the neuroinflammation reaction against Aβ plaques when S1P was compared with other treatments, suggesting that S1P plays a key role as a neuroprotective agent. Moreover, EB101 immunized mice presented a protective immunogenic reaction resulting in the increase of Aβ-specific antibody response and decrease of reactive glia in the affected brain areas, leading to a Th2 immunological reaction.

Chemometric design to explore pharmacophore features of BACE inhibitors for controlling Alzheimer's disease

Pharmacophoric features of potent BACE inhibitors derived from multi-chemometric studies.

Epigenetic drug discovery for Alzheimer's disease

INTRODUCTION

It is assumed that epigenetic modifications are reversible and could potentially be targeted by pharmacological and dietary interventions. Epigenetic drugs are gaining particular interest as potential candidates for the treatment of Alzheimer's disease (AD).

AREAS COVERED

This article covers relevant information from over 50 different epigenetic drugs including: DNA methyltransferase inhibitors; histone deacetylase inhibitors; histone acetyltransferase modulators; histone methyltransferase inhibitors; histone demethylase inhibitors; non-coding RNAs (microRNAs) and dietary regimes. The authors also review the pharmacoepigenomics and the pharmacogenomics of epigenetic drugs. The readers will gain insight into i) the classification of epigenetic drugs; ii) the mechanisms by which these drugs might be useful in AD; iii) the pharmacological properties of selected epigenetic drugs; iv) pharmacoepigenomics and the influence of epigenetic drugs on genes encoding CYP enzymes, transporters and nuclear receptors; and v) the genes associated with the pharmacogenomics of anti-dementia drugs.

EXPERT OPINION

Epigenetic drugs reverse epigenetic changes in gene expression and might open future avenues in AD therapeutics. Unfortunately, clinical trials with this category of drugs are lacking in AD. The authors highlight the need for pharmacogenetic and pharmacoepigenetic studies to properly evaluate any efficacy and safety issues.

Pharmacogenomics of Alzheimer's disease: novel therapeutic strategies for drug development

Alzheimer's disease (AD) is a major problem of health and disability, with a relevant economic impact on our society. Despite important advances in pathogenesis, diagnosis, and treatment, its primary causes still remain elusive, accurate biomarkers are not well characterized, and the available pharmacological treatments are not cost-effective. As a complex disorder, AD is a polygenic and multifactorial clinical entity in which hundreds of defective genes distributed across the human genome may contribute to its pathogenesis. Diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena, together with structural and functional genomic dysfunctions, lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death, the major neuropathological hallmarks of AD. Future perspectives for the global management of AD predict that genomics and proteomics may help in the search for reliable biomarkers. In practical terms, the therapeutic response to conventional drugs (cholinesterase inhibitors, multifactorial strategies) is genotype-specific. Genomic factors potentially involved in AD pharmacogenomics include at least five categories of gene clusters: (1) genes associated with disease pathogenesis; (2) genes associated with the mechanism of action of drugs; (3) genes associated with drug metabolism (phase I and II reactions); (4) genes associated with drug transporters; and (5) pleiotropic genes involved in multifaceted cascades and metabolic reactions. The implementation of pharmacogenomic strategies will contribute to optimize drug development and therapeutics in AD and related disorders.

Personalized Medicine of Alzheimer’s Disease

Alzheimer’s disease (AD) is a major problem of health and disability, with a relevant economic impact on society (e.g., €177 billion in Europe). Despite important advances in pathogenesis, diagnosis, and treatment, The primary causes of AD remain elusive, accurate biomarkers are not well characterized, and available pharmacological treatments are not cost-effective. As a complex disorder, AD is polygenic and multifactorial: hundreds of defective genes distributed across the human genome may contribute to its pathogenesis (with the participation of diverse environmental factors, cerebrovascular dysfunction, and epigenetic phenomena) and lead to amyloid deposition, neurofibrillary tangle formation, and premature neuronal death. Future perspectives for the global management of AD predict that structural and functional genomics and proteomics may help in the search for reliable biomarkers, and that pharmacogenomics may be an option in optimizing drug development and therapeutics.

Potential involvement of GRIN2B encoding the NMDA receptor subunit NR2B in the spectrum of Alzheimer's disease

Increasing evidence links dysregulation of NR2B-containing N-methyl-D-aspartate receptor remodelling and trafficking to Alzheimer's disease (AD). This theme offers the possibility that the GRIN2B gene, encoding this selective NR2B subunit, represents a potential molecular modulating factor for this disease. Based on this hypothesis, we carried out a mutation scanning of exons and flanking regions of GRIN2B in a well-characterized cohort of AD patients, recruited from Southern Italy. A "de novo" p.K1293R mutation, affecting a highly conserved residue of the protein in the C-terminal domain, was observed for the first time in a woman with familial AD, as the only genetic alteration of relevance. Moreover, an association study between the other detected sequence variants and AD was performed. In particular, the study was focused on five identified single nucleotide polymorphisms: rs7301328, rs1805482, rs3026160, rs1806191 and rs1806201, highlighting a significant contribution from the GRIN2B rs1806201 T allele towards disease susceptibility [adjusted odds ratio (OR) = 1.92, 95% confidence interval (CI) 1.40-2.63, p < 0.001, after correction for sex, age, and APOE ε4 genotype]. This was confirmed by haplotype analysis that identified a specific haplotype, carrying the rs1806201 T allele (CCCTC), over-represented in patients versus controls (adjusted OR = 6.03; p < 0.0001). Although the pathogenic role of the GRIN2B-K1293R mutation in AD is not clear, our data advocate that genetic variability in the GRIN2B gene, involved in synaptic functioning, might provide valuable insights into disease pathogenesis, continuing to attract significant attention in biomedical research on its genetic and functional role.

High cortisol levels are associated with cognitive impairment no-dementia (CIND) and dementia

BACKGROUND

This study aimed to compare serum cortisol concentrations in cognitively healthy elderly and in subjects with cognitive impairment no dementia (CIND) and dementia, besides to evaluate these concentrations according to apolipoprotein E genotype (APOE).

METHODS

Three-hundred and nine elderly enrolled in the Pietà Study (Brazil) were divided in 3 groups: control (n=158), CIND (n=92) and dementia (n=59) and had concentrations of morning serum cortisol measured. Hormone concentrations were measured by chemiluminescence and APOE genotypes were determined by PCR followed by restriction fragment length polymorphism (RFLP).

RESULTS

Medians of cortisol concentrations (μg/dl) for the groups were 12.14 (interquartile range - IQR 6.34) for control, 13.65 (IQR 5.88) for CIND and 14.47 (IQR 7.35) for dementia. Significant differences were observed for control vs. CIND (P=0.003), control vs. dementia (P=0.001), but not for CIND vs. dementia (P=0.269). No association was observed between cortisol concentrations and APOE genotype among the groups (P=0.348).

CONCLUSIONS

The elevation in cortisol concentrations is associated with dementia, independently of APOE genotypes. Further studies are required to understand if elevation of cortisol is an initial event and how hippocampal damage and the loss of hypothalamus-pituitary-adrenal (HPA) axis inhibition may affect its concentrations.

Polymorphism of CLOCK gene rs 4580704 C > G is associated with susceptibility of Alzheimer's disease in a Chinese population

BACKGROUND AND AIMS

The association of polymorphism of circadian locomotor output cycle kaput (CLOCK) gene rs 4580704 C/G with susceptibility of Alzheimer's disease (AD) was examined in the present study.

METHODS

This was a case/control study and investigated the association of polymorphism of CLOCK gene rs 4580704 C/G with susceptibility of AD. Genotypes of apolipoprotein E (APOE) and CLOCK gene rs 4580704 C/G were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) detection method.

RESULTS

This study was comprised of 296 unrelated AD patients and 423 controls. We performed an analysis the association of polymorphism of CLOCK gene rs 4580704 C/G with susceptibility of AD. In the whole sample or APOEε4 noncarriers, prevalence of C carriers in CLOCK gene rs 4580704 in AD patients was significantly higher than in controls (in the whole sample: χ(2) = 13.773, p <0.0001; in APOEε4 noncarriers: χ(2) = 51.588, p <0.0001). However, among APOEε4 carriers, prevalence of C carriers in CLOCK gene rs 4580704 between patients and controls was not statistically significant (χ(2) = 0.753, p = 0.386).

CONCLUSIONS

Among APOEε4 noncarriers, C carriers in CLOCK gene rs 4580704 were associated with a high susceptibility of AD; however, among APOEε4 carriers the functional polymorphism of clock gene rs 4580704 C/G was not associated with AD susceptibility.

Vaccine Development to Treat Alzheimer's Disease Neuropathology in APP/PS1 Transgenic Mice

A novel vaccine addressing the major hallmarks of Alzheimer's disease (AD), senile plaque-like deposits of amyloid beta-protein (Aβ), neurofibrillary tangle-like structures, and glial proinflammatory cytokines, has been developed. The present vaccine takes a new approach to circumvent failures of previous ones tested in mice and humans, including the Elan-Wyeth vaccine (AN1792), which caused massive T-cell activation, resulting in a meningoencephalitis-like reaction. The EB101 vaccine consists of Aβ_1-42 delivered in a novel immunogen-adjuvant composed of liposomes-containing sphingosine-1-phosphate (S1P). EB101 was administered to APPswe/PS1dE9 transgenic mice before and after AD-like pathological symptoms were detectable. Treatment with EB101 results in a marked reduction of Aβ plaque burden, decrease of neurofibrillary tangle-like structure density, and attenuation of astrocytosis. In this transgenic mouse model, EB101 reduces the basal immunological interaction between the T cells and immune activation markers in the affected hippocampal/cortical areas, consistent with decreased amyloidosis-induced inflammation. Therefore, immunization with EB101 prevents and reverses AD-like neuropathology in a significant manner by halting disease progression without developing behavioral spatial deficits in transgenic mice.

Translating Mendelian and complex inheritance of Alzheimer's disease genes for predicting unique personal genome variants

Objective

Although trait-associated genes identified as complex versus single-gene inheritance differ substantially in odds ratio, the authors nonetheless posit that their mechanistic concordance can reveal fundamental properties of the genetic architecture, allowing the automated interpretation of unique polymorphisms within a personal genome.

Materials and methods

An analytical method, SPADE-gen, spanning three biological scales was developed to demonstrate the mechanistic concordance between Mendelian and complex inheritance of Alzheimer's disease (AD) genes: biological functions (BP), protein interaction modeling, and protein domain implicated in the disease-associated polymorphism.

Results

Among Gene Ontology (GO) biological processes (BP) enriched at a false detection rate <5% in 15 AD genes of Mendelian inheritance (Online Mendelian Inheritance in Man) and independently in those of complex inheritance (25 host genes of intragenic AD single-nucleotide polymorphisms confirmed in genome-wide association studies), 16 overlapped (empirical p=0.007) and 45 were similar (empirical p<0.009; information theory). SPAN network modeling extended the canonical pathway of AD (KEGG) with 26 new protein interactions (empirical p<0.0001).

Discussion

The study prioritized new AD-associated biological mechanisms and focused the analysis on previously unreported interactions associated with the biological processes of polymorphisms that affect specific protein domains within characterized AD genes and their direct interactors using (1) concordant GO-BP and (2) domain interactions within STRING protein–protein interactions corresponding to the genomic location of the AD polymorphism (eg, EPHA1, APOE, and CD2AP).

Conclusion

These results are in line with unique-event polymorphism theory, indicating how disease-associated polymorphisms of Mendelian or complex inheritance relate genetically to those observed as ‘unique personal variants’. They also provide insight for identifying novel targets, for repositioning drugs, and for personal therapeutics.

Genomics of Dementia: APOE- and CYP2D6-Related Pharmacogenetics

Dementia is a major problem of health in developed societies. Alzheimer's disease (AD), vascular dementia, and mixed dementia account for over 90% of the most prevalent forms of dementia. Both genetic and environmental factors are determinant for the phenotypic expression of dementia. AD is a complex disorder in which many different gene clusters may be involved. Most genes screened to date belong to different proteomic and metabolomic pathways potentially affecting AD pathogenesis. The ε4 variant of the APOE gene seems to be a major risk factor for both degenerative and vascular dementia. Metabolic factors, cerebrovascular disorders, and epigenetic phenomena also contribute to neurodegeneration. Five categories of genes are mainly involved in pharmacogenomics: genes associated with disease pathogenesis, genes associated with the mechanism of action of a particular drug, genes associated with phase I and phase II metabolic reactions, genes associated with transporters, and pleiotropic genes and/or genes associated with concomitant pathologies. The APOE and CYP2D6 genes have been extensively studied in AD. The therapeutic response to conventional drugs in patients with AD is genotype specific, with CYP2D6-PMs, CYP2D6-UMs, and APOE-4/4 carriers acting as the worst responders. APOE and CYP2D6 may cooperate, as pleiotropic genes, in the metabolism of drugs and hepatic function. The introduction of pharmacogenetic procedures into AD pharmacological treatment may help to optimize therapeutics.

Genomics and pharmacogenomics of dementia

Dementia is a major problem of health in developed countries, and a prototypical paradigm of chronic disability, high cost, and social-family burden. Approximately, 10-20% of direct costs in this kind of neuropathology are related to pharmacological treatment, with a moderate responder rate below 30% and questionable cost-effectiveness. Over 200 different genes have been associated with the pathogenesis of dementia. Studies on structural and functional genomics, transcriptomics, proteomics and metabolomics have revealed the paramount importance of these novel technologies for the understanding of pathogenic cascades and the prediction of therapeutic outcomes in dementia. About 10-30% of Western populations are defective in genes of the CYP superfamily. The most frequent CYP2D6 variants in the Iberian peninsula are the *1/*1 (57.84%), *1/*4 (22.78%), *1×N/*1 (6.10%), *4/*4 (2.56%), and *1/*3 (2.01%) genotypes, accounting for more than 80% of the population. The frequency of extensive (EMs), intermediate (IMs), poor (PMs), and ultra-rapid metabolizers (UMs) is about 59.51%, 29,78%, 4.46%, and 6.23%, respectively, in the general population, and 57.76, 31.05%, 5.27%, and 5.90%, respectively, in AD cases. The construction of a genetic map integrating the most prevalent CYP2D6+CYP2C19+CYP2C9 polymorphic variants in a trigenic cluster yields 82 different haplotype-like profiles, with *1*1-*1*1-*1*1 (25.70%), *1*1-*1*2-*1*2 (10.66%), *1*1-*1*1-*1*1 (10.45%), *1*4-*1*1-*1*1 (8.09%), *1*4-*1*2-*1*1 (4.91%), *1*4-*1*1-*1*2 (4.65%), and *1*1-*1*3-*1*3 (4.33%), as the most frequent genotypes. Only 26.51% of AD patients show a pure 3EM phenotype, 15.29% are 2EM1IM, 2.04% are pure 3IM, 0% are pure 3PM, and 0% are 1UM2PM. EMs and IMs are the best responders, and PMs and UMs are the worst responders to a combination therapy with cholinesterase inhibitors, neuroprotectants, and vasoactive substances. The pharmacogenetic response in AD appears to be dependent upon the networking activity of genes involved in drug metabolism and genes involved in AD pathogenesis (e.g., APOE). AD patients harboring the APOE-4/4 genotypes are the worst responders to conventional antidementia drugs. To achieve a mature discipline of pharmacogenomics in CNS disorders and dementia it would be convenient to accelerate the following processes: (i) to educate physicians and the public on the use of genetic/genomic screening in daily clinical practice; (ii) to standardize genetic testing for major categories of drugs; (iii) to validate pharmacogenomic information according to drug category and pathology; (iv) to regulate ethical, social, and economic issues; and (v) to incorporate pharmacogenomic procedures both to drugs in development and drugs on the market in order to optimize therapeutics.

Genomics and pharmacogenomics of schizophrenia

Schizophrenia (SCZ) is among the most disabling of mental disorders. Several neurobiological hypotheses have been postulated as responsible for SCZ pathogenesis: polygenic/multifactorial genomic defects, intrauterine and perinatal environment-genome interactions, neurodevelopmental defects, dopaminergic, cholinergic, serotonergic, gamma-aminobutiric acid (GABAergic), neuropeptidergic and glutamatergic/N-Methyl-D-Aspartate (NMDA) dysfunctions, seasonal infection, neuroimmune dysfunction, and epigenetic dysregulation. SCZ has a heritability estimated at 60-90%. Genetic studies in SCZ have revealed the presence of chromosome anomalies, copy number variants, multiple single-nucleotide polymorphisms of susceptibility distributed across the human genome, aberrant single nucleotide polymorphisms (SNPs) in microRNA genes, mitochondrial DNA mutations, and epigenetic phenomena. Pharmacogenetic studies of psychotropic drug response have focused on determining the relationship between variation in specific candidate genes and the positive and adverse effects of drug treatment. Approximately, 18% of neuroleptics are major substrates of CYP1A2 enzymes, 40% of CYP2D6, and 23% of CYP3A4; 24% of antidepressants are major substrates of CYP1A2 enzymes, 5% of CYP2B6, 38% of CYP2C19, 85% of CYP2D6, and 38% of CYP3A4; 7% of benzodiazepines are major substrates of CYP2C19 enzymes, 20% of CYP2D6, and 95% of CYP3A4. About 10-20% of Western populations are defective in genes of the CYP superfamily. Only 26% of Southern Europeans are pure extensive metabolizers for the trigenic cluster integrated by the CYP2D6+CYP2C19+CYP2C9 genes. The pharmacogenomic response of SCZ patients to conventional psychotropic drugs also depends on genetic variants associated with SCZ-related genes. Consequently, the incorporation of pharmacogenomic procedures both to drugs in development and drugs on the market would help to optimize therapeutics in SCZ and other central nervous system (CNS) disorders.

Synthesis and in vitro evaluation of 7-methoxy-N-(pent-4-enyl)-1,2,3,4-tetrahydroacridin-9-amine-new tacrine derivate with cholinergic properties

Cholinesterase inhibitors are, so far, the only successful strategy for the symptomatic treatment of Alzheimer's disease. Tacrine (THA) is a potent acetylcholinesterase inhibitor that was used in the treatment of Alzheimer's disease for a long time. However, the clinical use of THA was hampered by its low therapeutic index, short half-life and liver toxicity. 7-Methoxytacrine (7-MEOTA) is equally pharmacological active compound with lower toxicity compared to THA. In this Letter, the synthesis, biological activity and molecular modelling of elimination by-product isolated during synthesis of 7-MEOTA based bis-alkylene linked compound is described.

Hypoxia-induced down-regulation of neprilysin by histone modification in mouse primary cortical and hippocampal neurons

Amyloid β-peptide (Aβ) accumulation leads to neurodegeneration and Alzheimer's disease (AD). Aβ metabolism is a dynamic process in the Aβ production and clearance that requires neprilysin (NEP) and other enzymes to degrade Aβ. It has been reported that NEP expression is significantly decreased in the brain of AD patients. Previously we have documented hypoxia is a risk factor for Aβ generation in vivo and in vitro through increasing Aβ generation by altering β-cleavage and γ-cleavage of APP and down-regulating NEP, and causing tau hyperphosphorylation. Here, we investigated the molecular mechanisms of hypoxia-induced down-regulation of NEP. We found a significant decrease in NEP expression at the mRNA and protein levels after hypoxic treatment in mouse primary cortical and hippocampal neurons. Chromatin immunoprecipitation (ChIP) assays and relative quantitative PCR (q-PCR) revealed an increase of histone H3-lysine9 demethylation (H3K9me2) and a decrease of H3 acetylation (H3-Ace) in the NEP promoter regions following hypoxia. In addition, we found that hypoxia caused up-regulation of histone methyl transferase (HMT) G9a and histone deacetylases (HDACs) HDAC-1. Decreased expression of NEP during hypoxia can be prevented by application with the epigenetic regulators 5-Aza-2′-deoxycytidine (5-Aza), HDACs inhibitor sodium valproate (VA), and siRNA-mediated knockdown of G9a or HDAC1. DNA methylation PCR data do not support that hypoxia affects the methylation of NEP promoters. This study suggests that hypoxia may down-regulate NEP by increasing H3K9me2 and decreasing H3-Ace modulation.