Association of ALOX15 Gene Polymorphism with Ischemic Stroke in Northern Chinese Han Population

Association of Rs7217186 Polymorphism of Arachidonic Acid 15-Lipoxygenase (ALOX15) Gene with Susceptibility to Allergic Rhinitis

Background

Allergic rhinitis (AR) is an inflammatory disorder of the nasal mucosa, caused by exposure to environmental allergens. It is known that 15-lipoxygenase (15-LOX) is involved in the biosynthetic pathways of anti-inflammatory lipid mediators, including resolvins and protectins.

Methods

In this study, which was performed on 130 AR patients and 130 healthy controls, we aimed to investigate the association of susceptibility to AR with two selected single-nucleotide polymorphisms (SNPs), that is, rs2619112:A>G and rs7217186:C>T, in the intron regions of arachidonic acid 15-LOX (ALOX15) gene, using SNPinfo and Regulome DB tools.

Results

The results showed that the CT genotype of rs7217186: C>T was significantly associated with the increased risk of AR compared to the CC genotype (P= 0.037, OR=1.943, CI: 1.038-0.638). However, there was no strong evidence of the association of rs2619112: A>G with susceptibility to AR (P> 0.05).

Conclusions

The present results indicated that rs7217186 polymorphism of ALOX15 gene might be a potential biomarker for susceptibility to AR.

Polyunsaturated fatty acids, specialized pro-resolving mediators, and targeting inflammation resolution in the age of precision nutrition

Chronic inflammation contributes toward the pathogenesis of numerous diseases including, but not limited to, obesity, autoimmunity, cardiovascular diseases, and cancers. The discovery of specialized pro-resolving mediators (SPMs), which are critical for resolving inflammation, has commenced investigation into targeting pathways of inflammation resolution to improve physiological outcomes. SPMs are predominately synthesized from the n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Therefore, one viable strategy to promote inflammation resolution would be to increase dietary intake of EPA/DHA, which are deficient in select populations. However, there are inconsistencies between the use of EPA/DHA as dietary or pharmacological supplements and improved inflammatory status. Herein, we review the literature on the relationship between the high n-6/n-3 PUFA ratio, downstream SPM biosynthesis, and inflammatory endpoints. We highlight key studies that have investigated how dietary intake of EPA/DHA increase tissue SPMs and their effects on inflammation. We also discuss the biochemical pathways by which EPA/DHA drive SPM biosynthesis and underscore mechanistic gaps in knowledge about these pathways which include a neglect for host genetics/ethnic differences in SPM metabolism, sexual dimorphism in SPM levels, and potential competition from select dietary n-6 PUFAs for enzymes of SPM synthesis. Altogether, establishing how dietary PUFAs control SPM biosynthesis in a genetic- and sex-dependent manner will drive new precision nutrition studies with EPA/DHA to prevent chronic inflammation in select populations.

Arachidonic Acid Metabolites in Neurologic Disorders

BACKGROUND & OBJECTIVE

Arachidonic acid (ARA) is essential for the fluidity, selective permeability, and flexibility of the cell membrane. It is an important factor for the function of all cells, particularly in the nervous system, immune system, and vascular endothelium. ARA, after docosahexaenoic acid, is the second most common polyunsaturated fatty acid in the phospholipids of the nerve cell membrane. ARA metabolites have many kinds of physiologic roles. The major action of ARA metabolites is the promotion of the acute inflammatory response, mediated by the production of pro-inflammatory mediators such as PGE2 and PGI2, followed by the formation of lipid mediators, which have pro-resolving effects. Another important action of ARA derivatives, especially COX, is the regulation of vascular reactivity through PGs and TXA2. There is significant involvement of ARA metabolites in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and neuropsychiatric disorders. ARA derivatives also make an important contribution to acute stroke, global ischemia, subarachnoid hemorrhage, and anticoagulation- related hemorrhagic transformation.

CONCLUSION

In this review, we discuss experimental and human study results of neurologic disorders related to ARA and its metabolites in line with treatment options.

12/15 Lipoxygenase as a Therapeutic Target in Brain Disorders

Lipoxygenases are a family of lipid-oxidizing enzymes, which generate eicosanoids and related compounds from arachidonic acid and other polyunsaturated fatty acids. These metabolites play important roles in physiology and pathogenesis of host defense mechanisms, cardiovascular diseases, cancer, inflammatory, allergic and neurodegenerative diseases. The 12/15-lipoxygenase (LOX) is special in that it can directly oxidize lipid membranes containing polyunsaturated fatty acids, without the preceding action of a phospholipase, leading to the direct attack on membranous organelles, such as mitochondria. The cytotoxic activity of human 12/15-LOX is up-regulated in neurons and endothelial cells especially after a stroke and thought to contribute to both neuronal cell death and blood-brain barrier leakage. The discovery of inhibitors that selectively target recombinant 12/15-LOX in vitro, as well as possessing activity against the murine orthologous ex vivo, could potentially support a novel therapeutic strategy for the treatment of stroke and other brain disorders related to 12/15-LOX. Here we reviewed 12/15-LOX chemistry shortly, and the diseases in which 12/15-LOX has a role in their pathophysiology and recent advances of 12/15-LOX inhibitors as a treatment option for neurological diseases.

The Role of Polymorphism Gen Methylene Tetra Hydrofolate Reductase (MTHFR) C677T in Ischaemic Stroke Patients with and Without Hypertension

BACKGROUND:

Stroke is a leading cause of disability and remains the second leading cause of death in the world. Some of the pathogenesis of stroke are interactions between genetic and acquired risk factors, the interaction is related with the atherosclerotic which is the main pathogenesis of ischaemic stroke. Previous studies demonstrated an association between methylene tetra hydro folate reductase (MTHFR) genotype and ischaemic stroke; the MTHFR C677T genotype is one of the independent risk factor.

AIM:

This study aims to know about the role of polymorphism gen MTHFR C677T in ischaemic stroke patients with and without hypertension.

METHODS:

This study is a cross-sectional study, the sample was taken consecutively, after approval by the Medical Faculty Science’s Ethics Committee at University Sumatera Utara. All sample matched with inclusion and exclusion criteria, demography data and blood sample were taken. Demography data were analysed using descriptive statistic.

RESULTS:

Of the 106 ischaemic stroke patients were divided into two groups, the first group is patients with hypertension (53 patients), and the second group is without hypertension (53 patients). We have done the PCR- RFLP to all the patients, we got 78 patients with 677CC of MTHFR genotype, 23 patients with 677CT genotype and 5 patients with 677TT genotype. We found polymorphism C677T is more frequent in ischaemic stroke patients with hypertension (16 patients; 69.5%), and all the patient with 677TT genotype are an ischaemic stroke with hypertension (5 patients; 100%).

CONCLUSION:

We concluded that polymorphism MTHFR C677T have an important role in hypertension and ischaemic stroke.

Association of SAA gene polymorphism with ischemic stroke in northern Chinese Han population

BACKGROUND

Serum amyloid A protein (SAA) is known as an inflammatory factor and an apolipoprotein that can replace apolipoprotein A-I/II components as the major apolipoprotein of high-density lipoprotein (HDL), which is related to atherosclerosis. The present study is aimed to evaluate whether the SAA gene polymorphism is involved in ischemic stroke in northern Chinese Han population.

METHODS

In a case-control study, the participants included 396 patients (239 males, 157 females) with ischemic stroke and 360 healthy subjects (211 males, 149 females). The rs12218 polymorphism of the SAA gene was analyzed by polymerase chain reaction and restriction fragment length polymorphism, while the rs2468844 polymorphism of the SAA gene was analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

The frequencies of the CC genotype and the C allele of rs12218 were higher in participants with ischemic stroke than in the control group (P=0.020 in males, P=0.001 in large-artery atherosclerosis group, LAA). The frequencies of the AG genotype and the G allele of rs2468844 were higher in participants with ischemic stroke than in the control group (P=0.040 in males, P=0.011 in large-artery atherosclerosis group). Multiple logistic regression analysis revealed the significance of the rs12218 in males and in large-artery atherosclerosis group after adjustment for confounding factors.

CONCLUSION

The rs12218 polymorphism of the SAA gene was associated with ischemic stroke in males and in patients with large-artery atherosclerosis group in northern Chinese Han population.

Targeted deep resequencing of ALOX5 and ALOX5AP in patients with diabetes and association of rare variants with leukotriene pathways

The aim of the present study was to investigate a possible association between the accumulation of rare coding variants in the genes for arachidonate 5-lipoxygenase (ALOX5) and ALOX5-activating protein (ALOX5AP), and corresponding production of leukotrienes (LTs) in patients with type 2 diabetes mellitus (T2DM) receiving acetylsalicylic therapy. Twenty exons and corresponding introns of the selected genes were resequenced in 303 DNA samples from patients with T2DM using pooled polymerase chain reaction amplification and next-generation sequencing, using an Illumina HiSeq 2000 sequencing system. The observed non-synonymous variants were further confirmed by individual genotyping of DNA samples comprising of all individuals from the original discovery pools. The association between the investigated phenotypes was based on LTB4 and LTE4 concentrations, and the accumulation of rare missense variants (genetic burden) in investigated genes was evaluated using statistical collapsing tests. A total of 10 exonic variants were identified for each resequenced gene, including 5 missense and 5 synonymous variants. The rare missense variants did not exhibit statistically significant differences in the accumulation pattern between the patients with low and high LTs concentrations. As the present study only included patients with T2DM, it is unclear whether the absence of observed association between the accumulation of rare missense variants in investigated genes and LT production is associated with diabetic populations only or may also be applied to other populations.

A Novel Association of the Suppressor of Cytokine Signaling 1 (SOCS1) Gene Polymorphisms in Ischemic Stroke Patients

Ischemic stroke is a common neurological disease and a leading cause of permanent disability in many countries. Recent studies provide evidence on the role of the suppressor of the cytokine signaling 1 (SOCS1) gene in the development and progression of atherosclerotic lesions. However, few studies have assessed the association between single nucleotide polymorphisms (SNPs) on SOCS1 gene and ischemic stroke. Therefore, the present study aimed to investigate the role of SOCS1 polymorphism in ischemic stroke risk in a northern Chinese Han population. We examined 475 patients with ischemic stroke and 486 normal controls. Three SNPs (rs243327, rs243330, and rs33932899) of SOCS1 gene were determined for TaqMan genotyping assays. We also classified these case samples in depth by complications with hypertension or diabetes and by ischemic stroke subtypes. When adjusting models by multiple factor analysis by logistic regression, then calculated 10,000 permutations were performed for each model to correct the multiple test. Under additive model, the rs243327 was associated with ischemic stroke with hypertension (p = 0.047). Under heterozygous model, the rs33932899 and rs243330 were significantly associated with ischemic stroke subtypes by atherosclerosis (p = 0.038, p = 0.048, respectively). In summary, our data demonstrated for the first time that the polymorphisms of the SOCS1 gene are associated with the risk of ischemic stroke in a northern Chinese Han population, suggesting that SOCS1 gene polymorphisms may play an important role in the pathogenesis of ischemic stroke.

Association of nNOS gene polymorphism with ischemic stroke in Han Chinese of North China

Nitric oxide (NO) is an important messenger molecule and effector molecule. This study aimed to investigate the relation of neuronal nitric oxide synthase (nNOS) gene polymorphism with ischemic stroke in Han Chinese of North China. This was a case-control study. A total of 413 patients with ischemic stroke were recruited from Han Chinese of North China. There were 201 males and 212 females. In addition, 477 healthy subjects served as controls including 224 males and 253 females. Multiplex SNaPshot was employed to detect nNOS gene polymorphism (rs2293050, rs2139733, rs7308402, and rs1483757). Results showed that the rs1483757, rs2139733, and rs2293050 genotypes and allele frequencies were comparable between patients and controls. However, ischemic stroke patients had significantly reduced AG genotype and A allele frequency when compared with controls (P = 0.037, P = 0.041). After adjusting confounding factors (gender, age, smoking, history of drinking, hypertension, and diabetes), AG genotype and A allele were still related to ischemic stroke (OR = 0.572, 95% CI: 0.335–0.978, P = 0.041; OR = 0.611, 95% C: 0.378–0.985, and P = 0.041) and both were found to be protective factors. Our results showed that rs7308402 gene polymorphism of nNOS is related to ischemic stroke in Han Chinese of North China.

Molecular basis for the catalytic inactivity of a naturally occurring near-null variant of human ALOX15

Mammalian lipoxygenases belong to a family of lipid-peroxidizing enzymes, which have been implicated in cardiovascular, hyperproliferative and neurodegenerative diseases. Here we report that a naturally occurring mutation in the hALOX15 gene leads to expression of a catalytically near-null enzyme variant (hGly422Glu). The inactivity may be related to severe misfolding of the enzyme protein, which was concluded from CD-spectra as well as from thermal and chemical stability assays. In silico mutagenesis experiments suggest that most mutations at hGly422 have the potential to induce sterical clash, which might be considered a reason for protein misfolding. hGly422 is conserved among ALOX5, ALOX12 and ALOX15 isoforms and corresponding hALOX12 and hALOX5 mutants also exhibited a reduced catalytic activity. Interestingly, in the hALOX5 Gly429Glu mutants the reaction specificity of arachidonic acid oxygenation was shifted from 5S- to 8S- and 12R-H(p)ETE formation. Taken together, our data indicate that the conserved glycine is of functional importance for these enzyme variants and most mutants at this position lose catalytic activity.

A functional polymorphism at miR-491-5p binding site in the 3'-UTR of MMP-9 gene confers increased risk for atherosclerotic cerebral infarction in a Chinese population

BACKGROUND

and purpose: Matrix metalloproteinases 9 (MMP-9) has been reported to play a critical role in the pathophysiology of atherosclerotic cerebral infarction (ACI). Here we assessed association of MMP-9 polymorphisms with ACI susceptibility and the function of SNPs through microRNA mediated regulation.

METHODS

Genotyping was performed using MALDI-TOF mass spectrometry. Reporter gene plasmids with the MMP-9 3'UTR carrying either the mutant or the wild-type MMP-9 allele were constructed. Also, we constructed pcDNA-3.1-miR-491-5p recombinant plasmid, which transiently co-transfected human umbilical vein endothelial cells (HUVEC) with the reporter plasmids. Reporter plasmids, miR-491-5p mimics and inhibitor were transfected into HUVE cells line by lipofectamine. MMP-9 mRNA expression in HUVEC was detected by RT-PCR and protein level by ELISA.

RESULTS

The rs1802908 and rs2664517 polymorphisms were not observed in all subjects from Hunan Han Chinese. No significant difference in genotype distribution of rs20544 and rs9509 between cases and controls were observed (p＞0.05). The rs1056628CC genotype had a significantly increased risk for ACI as compared with carries of the rs1056628 A allele (total χ(2) = 12.041, P = 0.002). Reporter gene assay revealed that the rs1056628 A allele showed lower reporter activity than the rs1056628C allele. Hsa-miR-491-5p had effect on modulation of MMP-9 gene in vitro. The rs1056628 A→C variant in the 3'-UTR of the MMP-9 increased MMP-9 protein expression in cultured HUVECs.

CONCLUSIONS

Our data suggested that the rs1056629A→C variation contributes to an increased risk of ACI by increasing MMP-9 expression through affecting binding of miR-491 to the polymorphic site in the 3'-UTR of MMP-9.