The T-786C NOS3 polymorphism in Alzheimer's disease: Association and influence on gene expression

Machine Learning Approach to Identify Case-Control Studies on ApoE Gene Mutations Linked to Alzheimer’s Disease in Italy

Background: An application of artificial intelligence is machine learning, which allows computer programs to learn and create data. Methods: In this work, we aimed to evaluate the performance of the MySLR machine learning platform, which implements the Latent Dirichlet Allocation (LDA) algorithm in the identification and screening of papers present in the literature that focus on mutations of the apolipoprotein E (ApoE) gene in Italian Alzheimer’s Disease patients. Results: MySLR excludes duplicates and creates topics. MySLR was applied to analyze a set of 164 scientific publications. After duplicate removal, the results allowed us to identify 92 papers divided into two relevant topics characterizing the investigated research area. Topic 1 contains 70 papers, and topic 2 contains the remaining 22. Despite the current limitations, the available evidence suggests that articles containing studies on Italian Alzheimer’s Disease (AD) patients were 65.22% (n = 60). Furthermore, the presence of papers about mutations, including single nucleotide polymorphisms (SNPs) ApoE gene, the primary genetic risk factor of AD, for the Italian population was 5.4% (n = 5). Conclusion: The results show that the machine learning platform helped to identify case-control studies on ApoE gene mutations, including SNPs, but not only conducted in Italy.

Nitride oxide synthase 3 and klotho gene polymorphisms in the pathogenesis of chronic kidney disease and age-related cognitive impairment: a systematic review and meta-analysis

Background: While it has been known that the development of chronic kidney disease (CKD) and age-related cognitive impairment involves several mediators, the evidence in clinical practice only reveals nitride oxide synthase (NOS) and klotho. However, the evidence for this topic is conflicted. The aim of this study was to assess the role of NOS and klotho single nucleotide polymorphisms (SNPs) in the pathogenesis of CKD and age-related cognitive impairment. Methods: We performed a meta-analysis during October to December 2019. Paper collection was performed in major scientific websites, and we extracted information of interest from each paper. Data were analyzed using a Z-test with either random or fixed effect model. Results: Our initial assessment identified NOS3 G894T, NOS3 T786C, NOS3 4b/4a, klotho ( KL) G395A, and KL C1818T as the gene candidate for our meta-analysis. Our pooled calculation revealed that NOS3 G894T was associated with the risk of both age-related cognitive impairment and CKD. Increased susceptibility to age-related cognitive impairment was observed in the GG genotype, and increased risk of CKD was found in patients with a single T allele and TT genotype for NOS3 nucleotide 894. For NOS3 4b/4a, increased risk of CKD was only found in 4a4a genotype. For NOS3 T786C, we failed to show the association with both CKD and age-related cognitive impairment. Subsequently, for KL G395A, A allele and GA genotype were found to correlate with increased susceptibility to CKD, while its correlation to age-related cognitive impairment was failed to clarify. For KL C1818T, our analysis failed to find the correlation with the risk of CKD. Conclusions: Our results reveal that the NOS3 G894T gene polymorphism has a crucial role in the pathogenesis of both CKD and age-related cognitive impairment.

Nitride oxide synthase 3 and klotho gene polymorphisms in the pathogenesis of chronic kidney disease and age-related cognitive impairment: a systematic review and meta-analysis

Background: While it has been known that the development of chronic kidney disease (CKD) and age-related cognitive impairment involves several mediators, the evidence in clinical practice only reveals nitride oxide synthase (NOS) and klotho. However, the evidence for this topic is conflicted. The aim of this study was to assess the role of NOS and klotho single nucleotide polymorphisms (SNPs) in the pathogenesis of CKD and age-related cognitive impairment. Methods: We performed a meta-analysis during October to December 2019. Paper collection was performed in major scientific websites, and we extracted information of interest from each paper. Data were analyzed using a Z-test with either random or fixed effect model. Results: Our initial assessment identified NOS3 G894T, NOS3 T786C, NOS3 4b/4a, klotho ( KL) G395A, and KL C1818T as the gene candidate for our meta-analysis. Our pooled calculation revealed that NOS3 G894T was associated with the risk of both age-related cognitive impairment and CKD. Increased susceptibility to age-related cognitive impairment was observed in the GG genotype, and increased risk of CKD was found in patients with a single T allele and TT genotype for NOS3 nucleotide 894. For NOS3 4b/4a, increased risk of CKD was only found in 4a4a genotype. For NOS3 T786C, we failed to show the association with both CKD and age-related cognitive impairment. Subsequently, for KL G395A, A allele and GA genotype were found to correlate with increased susceptibility to CKD, while its correlation to age-related cognitive impairment was failed to clarify. For KL C1818T, our analysis failed to find the correlation with the risk of CKD. Conclusions: Our results reveal that the NOS3 G894T gene polymorphism has a crucial role in the pathogenesis of both CKD and age-related cognitive impairment.

The role of endothelial nitric oxide synthase -786 T/C polymorphism in cardiac instability following aneurysmal subarachnoid hemorrhage

INTRODUCTION

Cardiac abnormalities are observed frequently after aneurysmal subarachnoid hemorrhage (aSAH). A subset of aSAH patients develops neurogenic cardiomyopathy, likely induced by catecholamine excess. Genetic polymorphisms of the endothelial nitric oxide synthase (eNOS) gene have been linked to decreased nitric oxide (NO) levels, coronary artery spasm, and myocardial infarction. The role of the eNOS single nucleotide polymorphism (SNP) -786 T/C in cardiac instability following aSAH has not been previously investigated.

METHODS

From 2012 to 2015, aSAH patients were prospectively enrolled in the Cerebral Aneurysm Renin Angiotensin System (CARAS) study at two academic institutions. Blood samples were used to assess the eNOS SNP -786 T/C rs2070744 through 5'exonuclease (Taqman) genotyping assays. Associations between this polymorphism and cardiac instability following aSAH were analyzed.

RESULTS

Multivariable analysis demonstrated a dominant effect of the C allele of eNOS SNP -786 T/C on cardiac instability in patients with aSAH. A lower Glasgow Coma Scale score and a history of ischemic vascular disease were also associated with cardiac instability. Furthermore, cardiac instability independently predicted poor functional outcome upon discharge from the hospital.

CONCLUSIONS

The C allele of the eNOS SNP -786 T/C was independently associated with an increased risk for cardiac instability following aSAH. Cardiac instability itself was a risk factor for an unfavorable functional outcome upon discharge from the hospital.

Endothelial Nitric Oxide Synthase Polymorphism Is Associated with Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Nitric oxide is critical in the regulation of cerebral blood flow and smooth muscle proliferation. It is synthesized by 3 nitric oxide synthase (NOS) isoforms: neuronal, inducible, and endothelial NOS (eNOS). Aneurysmal subarachnoid hemorrhage (aSAH) causes endothelial dysfunction that, in turn, contributes to pathophysiologic processes surrounding aSAH. Previous studies reported an association of an eNOS single nucleotide polymorphism (SNP) with the clinical sequelae of aSAH. Here, we further elucidate the impact of this eNOS SNP on the clinical course after aSAH.

METHODS

The Cerebral Aneurysm Renin Angiotensin System study prospectively enrolled aSAH patients at 2 academic institutions in the United States from 2012-2015. Blood samples from all patients enrolled in the study were used for genetic evaluation using 5'exonuclease (Taqman) genotyping assays. Associations between the eNOS SNP rs2070744 (786 T->C) and clinical course after aSAH were analyzed.

RESULTS

Samples from 149 aSAH patients were available for analysis. The C allele of the eNOS SNP independently predicted an increased risk for delayed cerebral ischemia (OR = 2.936, 95% CI 1.048-8.226, P = 0.040). The eNOS SNP rs2070744 was not associated with functional outcome or size of aneurysm at the time of rupture.

CONCLUSIONS

The present study is the first to demonstrate that the C allele of the eNOS SNP 786 T->C rs2070744 is independently associated with an increased risk for delayed cerebral ischemia following aSAH.

Age and gender differences in the influences of eNOS T-786C polymorphism on arteriosclerotic parameters in general population in Japan

OBJECTIVE

The influence of T-786C polymorphism in the promoter region of endothelial nitric oxide synthase (eNOS) on arteriosclerotic parameters by age and gender were examined.

METHODS

Brachial-ankle pulse wave velocity (baPWV), heart-rate adjusted augmentation index (AIx@75), pulse pressure (PP) and albumin-creatinine ratio (ACR) were assessed as arteriosclerotic parameters in addition to non-high-density lipoprotein cholesterol (non-HDL-C) to HDL-C (non-HDL-C/HDL-C) ratio in 1499 participants. T-786C polymorphism (rs2070744) was screened using a TaqMan allelic discrimination assay. Analyses of covariance were carried.

RESULTS

Women with the non-C allele showed significantly lower AIx@75 in participants aged <65 years and baPWV in participants aged ≥65 years than those with C allele. In contrast, men with the non-C allele showed significantly higher PP in participants aged <65 years, and higher ACR and non-HDL-C/HDL-C ratio in participants aged ≥65 years. In men on cholesterol-lowering medication, the non-C allele carriers showed significantly higher non-HDL-C compared to those in the C allele carriers.

CONCLUSIONS

eNOS T-786C polymorphism is significantly associated with arteriosclerotic parameters accompanied with age and gender differences, possibly involving antioxidative and/or endothelial signaling other than inflammatory signaling.

Association between polymorphisms in NOS3 and KCNH2 and social memory

Social memory, including the ability to recognize faces and voices, is essential for social relationships. It has a large heritable component, but the knowledge about the contributing genes is sparse. The genetic variation underlying inter-individual differences in social memory was investigated in an exploratory sample (n = 55), genotyped with a chip comprising approximately 200,000 single nucleotide polymorphisms (SNPs), and in a validation sample (n = 582), where 30 SNPs were targeted. In the exploratory study face identity recognition was measured. The validation study also measured vocal sound recognition, as well as recognition of faces and vocal sounds combined (multimodal condition). In the exploratory study, the 30 SNPs that were associated with face recognition at p_uncorrected < 0.001 and located in genes, were chosen for further study. In the validation study two of these SNPs showed significant associations with recognition of faces, vocal sounds, and multimodal stimuli: rs1800779 in the gene encoding nitric oxide synthase 3 (NOS3) and rs3807370 in the gene encoding the voltage-gated channel, subfamily H, member 2 (KCNH2), in strong linkage disequilibrium with each other. The uncommon alleles were associated with superior performance, and the effects were present for men only (p < 0.0002). The exploratory study also showed a weaker but significant association with (non-emotional) word recognition, an effect that was independent of the effect on face recognition. This study demonstrates evidence for an association between NOS3 and KCNH2 SNPs and social memory.

Multi-level biomarker analysis of nitric oxide synthase isoforms in bipolar disorder and adult ADHD

INTRODUCTION

Several studies have shown altered levels of nitric oxide (NO) and its stable metabolites (NOx (-)) in blood and cerebrospinal fluid of psychiatric patients. The aim of our study was to replicate previous findings and investigate the influence of the nitrinergic system in bipolar disorder and adult attention-deficit/hyperactivity disorder (aADHD) in particular.

METHODS

The concentrations of NO2 (-) and NO3 (-) in peripheral blood in a sample of aADHD, bipolar disorder (BPD) and controls were analysed. The sample was genotyped for a three marker haplotype in the NOS3 gene (rs2070744, rs1799983 and Intron 4 VNTR) and for genetic variants of the NOS1 gene (NOS1 ex 1c, NOS1 ex 1f). Finally, qRT PCR was performed.

RESULTS

We found significantly lower NOx (-) levels in BPD (p<0.001). rs2070744 T/T-carriers of the whole sample showed increased mRNA expression of NOS3 (p=0.05). Only in BPD an influence of rs2070744 was seen regarding NO metabolite levels; C/C carriers displayed lower NOx (-) levels (p=0.05).

CONCLUSION

We could replicate and extend previous findings showing altered NOx (-) levels in BPD and an influence of NOS3 rs2070744 on NOS3 expression and NOx (-) concentration. Together, these data point to a role of the nitrinergic pathway in BPD.

Role of NOS3 DNA variants in externalizing behavioral problems observed in childhood leukemia survivors

OBJECTIVE

Neuropsychological problems occurrence varies among childhood cancer survivors, and associated risk factors have not been fully deciphered. We wanted to study the role of genetic variants in behavioral problems in this population.

STUDY DESIGN

Behavioral problems in pediatric acute lymphoblastic leukemia patients (n=138) were investigated longitudinally, using the Child Behavior Checklist questionnaire and multilevel statistical modeling. Thirty-four candidate polymorphisms, related to anticancer drug effects, were investigated.

RESULTS

NOS3 gene functional polymorphisms showed significant association: patients homozygous for the minor allele at investigated loci showed decreased externalizing behavioral problems scores over time (t tests: T-786C n=69, P=0.003; G894T n=71, P=0.065). The effect was even more pronounced for individuals that are homozygous for the -786C844T haplotype (t test, n=69, P<0.001) and results were supported by multilevel modeling analyses (P<0.001). No such association was observed for internalizing behavioral problems.

CONCLUSION

NOS3 variants modulate externalizing problems individual trajectories, likely in relationship with glucocorticoid exposure.

The NOS3 G894T (Glu298Asp) polymorphism is a risk factor for frontotemporal lobar degeneration

BACKGROUND AND AIMS

Neuronal nitric oxide synthase (NOS)1 C276T polymorphism was shown to increase the risk for frontotemporal lobar degeneration (FTLD). In the brain, both NOS1 and NOS3 (endothelial isoform) have been detected. The distribution of NOS3 G894T (Glu298Asp) and T-786C single nucleotide polymorphisms (SNPs) was analyzed in a population of 222 patients with FTLD compared with 218 age-matched controls to determine whether they could influence the susceptibility to develop the disease.

RESULTS

A statistically significant increased frequency of the NOS3 G894T SNP was observed in patients as compared with controls (40.0 vs. 31.4%, P = 0.011, OR: 1.65, CI: 1.13-2.42). Conversely, the distribution of the T-786C SNP was similar in patients and controls. No differences were observed stratifying according to gender.

DISCUSSION

The NOS3 G894T polymorphism likely acts as risk factor for sporadic FTLD, but studies in larger populations are needed to confirm these preliminary findings.

Behavioral genetics of neurodegenerative disorders

Alzheimer's disease (AD) is the most common cause of dementia in the elderly, and is typically characterized by memory loss. In addition, during the disease progression, most patients develop behavioural and psychiatric symptoms of dementia (BPSD). Frontotemporal Lobar Degeneration (FTLD) is the most frequent neurodegenerative disorder with a presenile onset. It is characterized mainly by behavioural disturbances, whereas memory is conserved. The two major neuropathologic hallmarks of AD are extracellular Amyloid beta (Ab) plaques and intracellular neurofibrillary tangles (NFTs). Conversely, in FTLD the deposition of tau has been observed in a number of cases, but in several brains there is no deposition of tau but instead a positivity for ubiquitin. In some families these diseases are inherited in an autosomal dominant fashion. Genes responsible for familial AD include the Amyloid Precursor Protein (b-APP), Presenilin 1 (PS1)and Presenilin 2 (PS2). The majority of mutations in these genes are often associated with a very early onset (40–50 years of age). Regarding FTLD, the first mutations described are located in the Microtubule Associated Protein Tau gene(MAPT). Tau is a component of microtubules, which represent the internal support structures for the transport of nutrients, vesicles, mitochondria and chromosomes within the cell. Mutations in MAPT are associated with an early onset of the disease (40–50 years), and the clinical phenotype is consistent with Frontotemporal Dementia (FTD). Recently, mutations in a second gene, named progranulin(GRN), have been identified in some families with FTLD. The pathology associated with these mutations is most frequently characterized by the immunostaining of TAR DNA Binding Protein 43 (TDP-43), which is a transcription factor. The clinical phenotype associated with GRN mutations is highly heterogeneous,including FTD, Progressive Aphasia, Corticobasal Syndrome, and AD. Age at disease onset is variable, ranging from 45 to 85 years of age. The majority of cases of AD and FTLD are however sporadic, and likely several genetic and environmental factors contribute to their development. Concerning AD, it is known that the presence of the e4 allele of the Apolipoprotein E gene is a susceptibility factor,increasing the risk of about 4 fold. A number of additional genetic factors,including cytokines, chemokines, Nitric Oxide Synthases, contribute to the susceptibility for the disease. Some of them also influence the risk to develop FTLD.Variability in serotonin transporter gene could influence the development of BPSD. In this chapter, current knowledge on molecular mechanisms at the basis of AD and FTLD, as well as the role of genetics, will be presented and discussed.

Nitric oxide synthase variants and disease-free survival among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial

PURPOSE

Numerous chemotherapeutic agents are cytotoxic through generation of reactive species, and variability in genes related to oxidative stress may influence disease-free survival (DFS). We examined relationships between DFS and variants in NOS3, as well as NQO1, NQO2, and CBR3, among treated and untreated breast cancer patients in a Southwest Oncology Group clinical trial (S8897).

EXPERIMENTAL DESIGN

In the parent trial, women were assigned according to prognostic features; the high-risk group was randomized to cyclophosphamide, i.v. methotrexate, and 5-fluorouracil or to cyclophosphamide, i.v. doxorubicin, and 5-fluorouracil +/- tamoxifen, and the low-risk group did not receive adjuvant therapy. We extracted DNA from normal lymph node tissue and examined functional polymorphisms in NOS3, NQO1, NQO2, and CBR3, in relation to DFS, using Cox proportional hazard model.

RESULTS

There were significant interactions between DFS, adjuvant therapy, and NOS3 Glu298Asp and -786 polymorphisms, alone and in combination (P for interaction = 0.008). When NOS3 genotypes were combined, women with genotypes encoding for lower nitric oxide who received chemotherapy had a >2-fold increase in hazard of progression (hazard ratio, 2.32; 95% confidence interval, 1.26-4.25), whereas there was reduced risk for those who did not receive adjuvant therapy (hazard ratio, 0.42; 95% confidence interval, 0.19-0.95). There were no associations between the other genotypes and DFS in either group.

CONCLUSION

Variants encoding lower activity of NOS3 may affect outcomes in breast cancer patients, with the direction of risk differing depending on chemotherapy status. These results may mirror the known dual functions of nitric oxide and nitric oxide synthase, depending on oxidative environment.

Genetic association between endothelial nitric oxide synthase and Alzheimer disease

Evidence suggests that vascular and inflammatory factors may be important in the etiology of Alzheimer disease (AD). The Glu/Glu genotype at the Glu298Asp variant of the endothelial nitric oxide synthase (NOS3) gene has been tested for association with AD in several Caucasian and Asian populations, with conflicting results. We tested the Glu298Asp variant for association in African American and Caucasian AD patients, unaffected siblings, and unrelated controls from the MIRAGE Study. To explore whether the inconsistent results in previous studies might be due to linkage disequilibrium with a polymorphism or haplotype not previously tested, we genotyped 10 additional NOS3 single nucleotide polymorphisms (SNPs) spanning 25.3 kb. Finally, we compiled results of previous studies of Glu298Asp using meta-analysis, to determine whether the aggregate studies support an association between Glu298Asp and AD. We found that the Glu298 allele was associated with higher risk of AD in the MIRAGE African American (p = 0.002) but not Caucasian (p = 0.9) groups. None of the additional SNPs were associated with AD in the Caucasians, whereas two showed evidence for association in the African Americans. The meta-analysis showed a small effect of the Glu298Asp GG genotype on AD risk across all studies (summary odds ratio = 1.15, 95% confidence interval: 0.97-1.35) and significant heterogeneity of this association among studies (p = 0.02).

Candidate gene analysis of IP-10 gene in patients with Alzheimer's disease

Interferon-gamma-inducible Protein-10 (IP-10) is supposed to play a role in Alzheimer's disease (AD) development, as demonstrated by increased levels in cerebrospinal fluid from patients with AD. A mutation scanning of IP-10 exonic region was carried out in 10 patients with AD and 10 age-matched controls, demonstrating the presence of two previously reported single nucleotide polymorphisms (SNPs) in exon 4 (G-->C and T-->C) as well as a novel SNP in exon 2 (C-->T). Exon 4 G-->C and T-->C allelic variants were next evaluated in a population of 279 AD patients and 251 controls, in order to determine whether their presence could influence the susceptibility towards the development of the disease. These two SNPs were in complete linkage disequilibrium. No differences in haplotype frequencies were found in AD patients as compared with controls, even stratifying according to the presence of Apolipoprotein E varepsilon4 allele, gender or age at onset. A new protocol was developed to easily determine the C-->T SNP in exon 2. A preliminary analysis revealed a very low frequency of this allelic variant (1%). Therefore, the complete association study was not carried out because the size of our population was not sufficient to draw reliable conclusions. According to these results, IP-10 does not seem to be a risk factor for AD. However, a novel rare polymorphism has been identified, which could exert a role in AD susceptibility. Thus, further studies on larger populations are needed before confidently excluding IP-10 as a susceptibility gene for AD.