Association between gut microbiota and CpG island methylator phenotype in colorectal cancer.

The intestinal microbiota is an important environmental factor implicated in CRC development. Intriguingly, modulation of DNA methylation by gut microbiota has been reported in preclinical models, although the relationship between tumor-infiltrating bacteria and CIMP status is currently unexplored. In this study, we investigated tumor-associated bacteria in 203 CRC tumor cases and validated the findings using The Cancer Genome Atlas datasets. We assessed the abundance of Bacteroides fragilis, Escherichia coli, Fusobacterium nucleatum, and Klebsiella pneumoniae through qPCR analysis and observed enrichment of all four bacterial species in CRC samples. Notably, except for E. coli, all exhibited significant enrichment in cases of CIMP. This enrichment was primarily driven by a subset of cases distinguished by high levels of these bacteria, which we labeled as "Superhigh". The bacterial Superhigh status showed a significant association with CIMP (odds ratio 3.1, p-value = 0.013) and with MLH1 methylation (odds ratio 4.2, p-value = 0.0025). In TCGA CRC cases (393 tumor and 45 adj. normal), bacterial taxa information was extracted from non-human whole exome sequencing reads, and the bacterial Superhigh status was similarly associated with CIMP (odds ratio 2.9, p < 0.001) and MLH1 methylation (odds ratio 3.5, p < 0.001). Finally, 16S ribosomal RNA gene sequencing revealed high enrichment of Bergeyella spp. C. concisus, and F. canifelinum in CIMP-Positive tumor cases. Our findings highlight that specific bacterial taxa may influence DNA methylation, particularly in CpG islands, and contribute to the development and progression of CIMP in colorectal cancer.

Epigenetic mechanisms regulate sex differences in cardiac reparative functions of bone marrow progenitor cells.

Historically, a lower incidence of cardiovascular diseases (CVD) and related deaths in women as compared with men of the same age has been attributed to female sex hormones, particularly estrogen and its receptors. Autologous bone marrow stem cell (BMSC) clinical trials for cardiac cell therapy overwhelmingly included male patients. However, meta-analysis data from these trials suggest a better functional outcome in postmenopausal women as compared with aged-matched men. Mechanisms governing sex-specific cardiac reparative activity in BMSCs, with and without the influence of sex hormones, remain unexplored. To discover these mechanisms, Male (M), female (F), and ovariectomized female (OVX) mice-derived EPCs were subjected to a series of molecular and epigenetic analyses followed by in vivo functional assessments of cardiac repair. F-EPCs and OVX EPCs show a lower inflammatory profile and promote enhanced cardiac reparative activity after intra-cardiac injections in a male mouse model of myocardial infarction (MI). Epigenetic sequencing revealed a marked difference in the occupancy of the gene repressive H3K9me3 mark, particularly at transcription start sites of key angiogenic and proinflammatory genes in M-EPCs compared with F-EPCs and OVX-EPCs. Our study unveiled that functional sex differences in EPCs are, in part, mediated by differential epigenetic regulation of the proinflammatory and anti-angiogenic gene CCL3, orchestrated by the control of H3K9me3 by histone methyltransferase, G9a/Ehmt2. Our research highlights the importance of considering the sex of donor cells for progenitor-based tissue repair.

Folic Acid Supplementation Promotes Hypomethylation in Both the Inflamed Colonic Mucosa and Colitis-Associated Dysplasia.

PURPOSE: The purpose of this study was to assess the effect of folic acid (FA) supplementation on colitis-associated colorectal cancer (CRC) using the azoxymethane/dextran sulfate sodium (AOM/DSS) model. METHODS: Mice were fed a chow containing 2 mg/kg FA at baseline and randomized after the first DSS treatment to receive 0, 2, or 8 mg/kg FA chow for 16 weeks. Colon tissue was collected for histopathological evaluation, genome-wide methylation analyses (Digital Restriction Enzyme Assay of Methylation), and gene expression profiling (RNA-Seq). RESULTS: A dose-dependent increase in the multiplicity of colonic dysplasias was observed, with the multiplicity of total and polypoid dysplasias higher (64% and 225%, respectively) in the 8 mg FA vs. the 0 mg FA group (p < 0.001). Polypoid dysplasias were hypomethylated, as compared to the non-neoplastic colonic mucosa (p < 0.05), irrespective of FA treatment. The colonic mucosa of the 8 mg FA group was markedly hypomethylated as compared to the 0 mg FA group. Differential methylation of genes involved in Wnt/ß-catenin and MAPK signaling resulted in corresponding alterations in gene expression within the colonic mucosa. CONCLUSIONS: High-dose FA created an altered epigenetic field effect within the non-neoplastic colonic mucosa. The observed decrease in site-specific DNA methylation altered oncogenic pathways and promoted colitis-associated CRC.

DNA polymerase θ protects leukemia cells from metabolically induced DNA damage.

Leukemia cells accumulate DNA damage, but altered DNA repair mechanisms protect them from apoptosis. We showed here that formaldehyde generated by serine/1-carbon cycle metabolism contributed to the accumulation of toxic DNA-protein crosslinks (DPCs) in leukemia cells, especially in driver clones harboring oncogenic tyrosine kinases (OTKs: FLT3(internal tandem duplication [ITD]), JAK2(V617F), BCR-ABL1). To counteract this effect, OTKs enhanced the expression of DNA polymerase theta (POLθ) via ERK1/2 serine/threonine kinase-dependent inhibition of c-CBL E3 ligase-mediated ubiquitination of POLθ and its proteasomal degradation. Overexpression of POLθ in OTK-positive cells resulted in the efficient repair of DPC-containing DNA double-strand breaks by POLθ-mediated end-joining. The transforming activities of OTKs and other leukemia-inducing oncogenes, especially of those causing the inhibition of BRCA1/2-mediated homologous recombination with and without concomitant inhibition of DNA-PK-dependent nonhomologous end-joining, was abrogated in Polq-/- murine bone marrow cells. Genetic and pharmacological targeting of POLθ polymerase and helicase activities revealed that both activities are promising targets in leukemia cells. Moreover, OTK inhibitors or DPC-inducing drug etoposide enhanced the antileukemia effect of POLθ inhibitor in vitro and in vivo. In conclusion, we demonstrated that POLθ plays an essential role in protecting leukemia cells from metabolically induced toxic DNA lesions triggered by formaldehyde, and it can be targeted to achieve a therapeutic effect.

Disrupted methylation patterns at birth persist in early childhood: a prospective cohort analysis.

BACKGROUND: Alterations in the epigenome are a risk factor in multiple disease states. We have demonstrated in the past that disruption of the epigenome during early pregnancy or periconception, as demonstrated by altered methylation, may be associated with both assisted reproductive technology and undesirable clinical outcomes at birth, such as low birth weight. We have previously defined this altered methylation, calculated based on statistical upper and lower limits of outlier CpGs compared to the population, as an 'outlier methylation phenotype' (OMP). Our aim in this study was to determine whether children thus identified as possessing an OMP at birth by DNA methylation in cord blood persist as outliers in early childhood based on salivary DNA methylation. RESULTS: A total of 31 children were included in the analysis. Among 24 children for whom both cord blood DNA and salivary DNA were available, DNA methylation patterns, analyzed using the Illumina Infinium MethylationEPIC BeadChip (850 K), between cord blood at birth and saliva in childhood at age 6-12 years remain stable (R2 range 0.89-0.97). At birth, three out of 28 children demonstrated an OMP in multiple cord blood datasets and hierarchical clustering. Overall DNA methylation among all three OMP children identified as outliers at birth was remarkably stable (individual R2 0.908, 0.92, 0.915), even when only outlier CpG sites were considered (R2 0.694, 0.738, 0.828). CONCLUSIONS: DNA methylation signatures in cord blood remain stable over time as demonstrated by a strong correlation with epigenetic salivary signatures in childhood. Future work is planned to identify whether a clinical phenotype is associated with OMP and, if so, could undesirable clinical outcomes in childhood and adulthood be predicted at birth.

Epigenome-Wide Study Identifies Epigenetic Outliers in Normal Mucosa of Patients with Colorectal Cancer.

Nongenetic predisposition to colorectal cancer continues to be difficult to measure precisely, hampering efforts in targeted prevention and screening. Epigenetic changes in the normal mucosa of patients with colorectal cancer can serve as a tool in predicting colorectal cancer outcomes. We identified epigenetic changes affecting the normal mucosa of patients with colorectal cancer. DNA methylation profiling on normal colon mucosa from 77 patients with colorectal cancer and 68 controls identified a distinct subgroup of normally-appearing mucosa with markedly disrupted DNA methylation at a large number of CpGs, termed as "Outlier Methylation Phenotype" (OMP) and are present in 15 of 77 patients with cancer versus 0 of 68 controls (P < 0.001). Similar findings were also seen in publicly available datasets. Comparison of normal colon mucosa transcription profiles of patients with OMP cancer with those of patients with non-OMP cancer indicates genes whose promoters are hypermethylated in the OMP patients are also transcriptionally downregulated, and that many of the genes most affected are involved in interactions between epithelial cells, the mucus layer, and the microbiome. Analysis of 16S rRNA profiles suggests that normal colon mucosa of OMPs are enriched in bacterial genera associated with colorectal cancer risk, advanced tumor stage, chronic intestinal inflammation, malignant transformation, nosocomial infections, and KRAS mutations. In conclusion, our study identifies an epigenetically distinct OMP group in the normal mucosa of patients with colorectal cancer that is characterized by a disrupted methylome, altered gene expression, and microbial dysbiosis. Prospective studies are needed to determine whether OMP could serve as a biomarker for an elevated epigenetic risk for colorectal cancer development. PREVENTION RELEVANCE: Our study identifies an epigenetically distinct OMP group in the normal mucosa of patients with colorectal cancer that is characterized by a disrupted methylome, altered gene expression, and microbial dysbiosis. Identification of OMPs in healthy controls and patients with colorectal cancer will lead to prevention and better prognosis, respectively.

Embryo cryopreservation leads to sex-specific DNA methylation perturbations in both human and mouse placentas.

In vitro fertilization (IVF) is associated with DNA methylation abnormalities and a higher incidence of adverse pregnancy outcomes. However, which exposure(s), among the many IVF interventions, contributes to these outcomes remains unknown. Frozen embryo transfer (ET) is increasingly utilized as an alternative to fresh ET, but reports suggest a higher incidence of pre-eclampsia and large for gestational age infants. This study examines DNA methylation in human placentas using the 850K Infinium MethylationEPIC BeadChip array obtained after 65 programmed frozen ET cycles, 82 fresh ET cycles and 45 unassisted conceptions. Nine patients provided placentas following frozen and fresh ET from consecutive pregnancies for a paired subgroup analysis. In parallel, eight mouse placentas from fresh and frozen ET were analyzed using the Infinium Mouse Methylation BeadChip array. Human and mouse placentas were significantly hypermethylated after frozen ET compared with fresh. Paired analysis showed similar trends. Sex-specific analysis revealed that these changes were driven by male placentas in humans and mice. Frozen and fresh ET placentas were significantly different from controls, with frozen samples hypermethylated compared with controls driven by males and fresh samples being hypomethylated compared with controls, driven by females. Sexually dimorphic epigenetic changes could indicate differential susceptibility to IVF-associated perturbations, which highlights the importance of sex-specific evaluation of adverse outcomes. Similarities between changes in mice and humans underscore the suitability of the mouse model in evaluating how IVF impacts the epigenetic landscape, which is valuable given limited access to human tissue and the ability to isolate specific interventions in mice.

Step-Headache: A Distinct Symptom of Migraine.

Objectives The diagnosis of migraine depends on various characteristics of headache with their associated constitutional symptoms such as nausea, vomiting, photophobia, and phonophobia. Relatively severe intensity, throbbing character, unilaterality, and aggravation with physical activity are the key features of migraine headache. We did this study to describe a new symptom (step-headache) in migraine in which some patients complained of uncomfortable or painful thump over the head with each footstep during walking or running. Materials and Methods Self-designed proforma was filled in each clinically diagnosed patient of migraine or tension-type headache in an outpatient clinic setting. The symptom designated here as step-headache was evaluated in 150 patients of migraine including 26 patients with overlapping headache and 244 patients of tension-type headache. Binary logistic regression was used for association analysis of step-headache with subgroups of migraine and with other migraine features. Statistical Analysis Frequency distributions were expressed as numbers (percentages) or mean ± standard deviation. Binary logistic regression was used for association analysis of step-headache with subgroups of migraine and with other migraine features. Results Step-headache was experienced by 97 (64.67%) migraine patients with nearly equal distribution among the two clinical subtypes (61.5% for migraine with aura and 65.3% for migraine without aura) but with high prevalence among perimenopausal onset migraine. Of all the patients who had this symptom, 77.32% experienced it during all the migraine attacks. The step-headache was differentiable from throbs of migraine and their exacerbation during physical activity by its synchrony with footsteps and its presence during nonpulsatile headaches or nonheadache phases of migraine. Sensitivity of this symptom was 64.67% while specificity was 100%. Conclusion Among primary headaches, step-headache is a less well-known but common and distinct symptom of migraine. It has good sensitivity and high specificity for migraine.

Epigenetic changes and assisted reproductive technologies.

Children conceived by Assisted Reproductive Technologies (ART) are at moderately increased risk for a number of undesirable outcomes, including low birth weight. Whether the additional risk is associated with specific procedures used in ART or biological factors that are intrinsic to infertility has been the subject of much debate, as has the mechanism by which ART or infertility might influence this risk. The potential effect of ART clinical and laboratory procedures on the gamete and embryo epigenomes heads the list of mechanistic candidates that might explain the association between ART and undesirable clinical outcomes. The reason for this focus is that the developmental time points at which ART clinical and laboratory procedures are implemented are precisely the time points at which large-scale reorganization of the epigenome takes place during normal development. In this manuscript, we review the many human studies comparing the epigenomes of ART children with children conceived in vivo, as well as assess the potential of individual ART clinical and laboratory procedures to alter the epigenome.

Highly variant DNA methylation in normal tissues identifies a distinct subclass of cancer patients.

The "CpG Island Methylator Phenotype" (CIMP) has been found to be a useful concept in stratifying several types of human cancer into molecularly and clinically distinguishable subgroups. We have identified an additional epigenetic stratification category, the "Outlier Methylation Phenotype" (OMP). Whereas CIMP is defined on the basis of hyper-methylation in tumor genomes, OMP is defined on the basis of highly variant (either or both hyper- and hypo-methylation) methylation at many sites in normal tissues. OMP was identified and defined, originally, as being more common among low birth weight individuals conceived in vitro but we have also identified OMP individuals among colon cancer patients profiled by us, as well as multiple types of cancer patients in the TCGA database. The cause(s) of OMP are unknown, as is whether these individuals identify a clinically useful subgroup of patients, but both the causes of, and potential consequences to, this epigenetically distinct group are of great interest.

Epigenetic changes in preterm birth placenta suggest a role for ADAMTS genes in spontaneous preterm birth.

Preterm birth (PTB) affects approximately 1 in 10 pregnancies and contributes to approximately 50% of neonatal mortality. However, despite decades of research, little is understood about the etiology of PTB, likely due to the multifactorial nature of the disease. In this study, we examined preterm and term placentas, from unassisted conceptions and those conceived using in vitro fertilization (IVF). IVF increases the risk of PTB and causes epigenetic change in the placenta and fetus; therefore, we utilized these patients as a unique population with a potential common etiology. We investigated genome-wide DNA methylation in placentas from term IVF, preterm IVF, term control (unassisted conception) and preterm control pregnancies and discovered epigenetic dysregulation of multiple genes involved in cell migration, including members of the ADAMTS family, ADAMTS12 and ADAMTS16. These genes function in extracellular matrix regulation and tumor cell invasion, processes replicated by invasive trophoblasts (extravillous trophoblasts (EVTs)) during early placentation. Though expression was similar between term and preterm placentas, we found that both genes demonstrate high expression in first- and second-trimester placenta, specifically in EVTs and syncytiotrophoblasts. When we knocked down ADAMTS12 or ADAMTS16in vitro, there was poor EVT invasion and reduced matrix metalloproteinase activity, reinforcing their critical role in placentation. In conclusion, utilizing a population at high risk for PTB, we have identified a role for ADAMTS gene methylation in regulating early placentation and susceptibility to PTB.

Global DNA methylation levels are altered by modifiable clinical manipulations in assisted reproductive technologies.

BACKGROUND: We analyzed placental DNA methylation levels at repeated sequences (LINE1 elements) and all CCGG sites (the LUMA assay) to study the effect of modifiable clinical or laboratory procedures involved in in vitro fertilization. We included four potential modifiable factors: oxygen tension during embryo culture, fresh embryo transfer vs frozen embryo transfer, intracytoplasmic sperm injection (ICSI) vs conventional insemination or day 3 embryo transfer vs day 5 embryo transfer. RESULTS: Global methylation levels differed between placentas from natural conceptions compared to placentas conceived by IVF. Placentas from embryos cultured at 20% oxygen showed significant differences in LINE1 methylation compared to in vivo conceptions, while those from embryos cultured at 5% oxygen, did not have significant differences. In addition, placentas from fresh embryo transfer had significantly different LINE1 methylation compared to placentas from in vivo conceptions, while embryos resulting from frozen embryos were not significantly different from controls. On sex-stratified analysis, only males had significant methylation differences at LINE1 elements stratified for the modifiable factors. As expected, LINE1 methylation was significantly different between males and females in the control population. However, we did not observe sex-specific differences in the IVF group. We validated this sex-specific observation in an additional cohort and in opposite sex IVF twins. CONCLUSION: We show that two clinically modifiable factors (embryo culture in 5 vs 20% oxygen tension and fresh vs frozen embryo transfer) are associated with global placental methylation differences. Interestingly, males appear more vulnerable to such treatment-related global changes in DNA methylation than do females.

Outlier DNA methylation levels as an indicator of environmental exposure and risk of undesirable birth outcome.

We have identified a novel molecular phenotype that defines a subgroup of newborns who have highly disrupted epigenomes. We profiled DNA methylation in cord blood of 114 children selected from the lowest and highest quintiles of the birth weight distribution (irrespective of their mode of conception) at 96 CpG sites in genes we have found previously to be related to birth weight or growth and metabolism. We identified those individuals in each group who differed from the mean of the distribution by the greatest magnitude at each site and for the largest number of sites. Such 'outlier' individuals differ substantially from the rest of the group in having highly disrupted methylation levels at many CpG sites. We find that children from the lowest quintile of the birth weight distribution have a significantly greater number of disrupted CpGs than children from the highest quintile of the birth weight distribution. Among children from the lowest quintile of the birth weight distribution, 'outlier' individuals are significantly more common among children conceived in vitro than children conceived in vivo. These observations are novel and potentially important because they associate a molecular phenotype (multiple and large DNA methylation differences) in normal somatic tissues (cord blood) with both a prenatal exposure (conception in vitro) and a clinically important outcome (low birth weight). These observations suggest that some individuals are more susceptible to environmentally mediated epigenetic alterations than others.

DNA methylation differences between in vitro- and in vivo-conceived children are associated with ART procedures rather than infertility.

BACKGROUND: We, and others, have demonstrated previously that there are differences in DNA methylation and transcript levels of a number of genes in cord blood and placenta between children conceived using assisted reproductive technologies (ART) and children conceived in vivo. The source of these differences (the effect of ART versus the underlying infertility) has never been determined in humans. In this study, we have attempted to resolve this issue by comparing placental DNA methylation levels at 37 CpG sites in 16 previously identified candidate genes in independent populations of children conceived in vivo ('fertile control' group) with ART children conceived from two groups: either autologous oocytes with infertility in one or both parents ('infertile ART' group) or donor oocytes (obtained from young fertile donors) without male infertility ('donor oocyte ART' group). RESULTS: Of the 37 CpG sites analyzed, significant differences between the three groups were found in 11 CpGs (29.73 %), using ANOVA. Tukey's post hoc test on the significant results indicated that seven (63.63 %) of these differences were significant between the donor oocyte ART and fertile control groups. In addition, 20 of the 37 CpGs analyzed had been identified as differentially methylated between ART and fertile control groups in an independent population in a prior study. Of these 20 CpG sites, 9 also showed significant differences in the present population. An additional 9 CpGs were found to be significantly different between the two groups. Of these 18 candidate CpGs, 12 CpGs (in seven candidate genes) also showed significant differences in placental DNA methylation levels between the donor oocyte ART and fertile control groups. CONCLUSIONS: These data suggest strongly that the DNA methylation differences observed between ART and in vivo conceptions are associated with some aspect of ART protocols, not simply the underlying infertility.

Genome-wide-associated variants in migraine susceptibility: a replication study from North India.

OBJECTIVE: Genome-wide association studies (GWAS) have identified various migraine susceptibility variants. We aim to replicate 5 GWAS-associated polymorphisms (rs1835740, LRP1 rs11172113, TRPM8 rs10166942, PRDM16 rs2651899, and TGFBR2 rs7640453) in the North Indian population. Furthermore, we checked the single nucleotide polymorphisms (SNPs) in strong linkage disequilibrium (LD) with the selected variants. We also undertook to predict the functional effect (in silico) of the variants. DESIGN: The study included 340 migraineurs and 200 controls. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), amplification-refractory mutation system (ARMS)-PCR, and Taqman. Logistic regression was used for association analysis. LD plot was prepared using genotyping data retrieved from ENCODE and HapMart. Functional effect was predicted by functional SNP (F-SNP)and FastSNP. RESULTS: We did not observe any significant effect of the variant genotype or allele of the first migraine GWAS associated marker, rs1835740. However, significance was observed in case of heterozygous genotype for total migraineurs and migraine without aura (MO). We suggest potential protective effect of LRP1 rs11172113 polymorphism in migraine susceptibility. PRDM16 rs2651899 variant genotype and allele showed a protective effect on migraine and MO susceptibility. On the other hand, TRPM8 rs10166942 and TGFBR2 rs7640543 variants did not have significant influence on migraine susceptibility in the North Indian population. Most of the selected SNPs (except LRP1 rs11172113) and some of the SNPs in strong LD were predicted to affect transcriptional regulation. Functional effect of LRP1 rs11172113 variant could not be predicted, but another SNP in the same LD block was found to affect transcription factor binding sites. CONCLUSION: We report significant influence of rs1835740, LRP1 rs11172113 and PRDM16 rs2651899 polymorphisms on migraine susceptibility in the North Indian population. Finally, we present the first replication study of GWAS-associated polymorphisms in a population other than European.

Identification of a novel ANKK1 and other dopaminergic (DRD2 and DBH) gene variants in migraine susceptibility.

The dopaminergic system plays an important role in migraine and its clinical subtypes. Hypersensitization of dopamine receptor type 2 (DRD2) in migraine led to successful administration of receptor antagonists in antimigraine therapy. Ankyrin repeats and kinase domain containing 1 (ANKK1) gene in DRD2 loci is linked to comorbid neurological disorders. Dopamine beta hydroxylase (DBH) is responsible for maintaining dopamine-to-norepinephrine ratio implicated in migraine pathophysiology. Therefore, we aimed to look for association of functional variants in ANKK1 (rs1800497), DRD2 (rs6275 and rs1799732) and DBH (rs7239728 and rs1611115) genes with migraine susceptibility. The present study was carried out in two dependent cohorts (n primary = 208, n secondary = 127, n controls = 200). The results of the cohorts were pooled by meta-analysis using Fisher's and Mantel-Haenszel test. Benjamini-Hochberg false discovery rate test was used to correct for multiple comparisons. Computer algorithm-based TANGO, WALTZ and LIMBO predictions were used to evaluate the effect of missense polymorphism (rs1800497). For ANKK1 polymorphism, variant genotype and allele showed significant associations with migraine risk. A significant protective effect of variant DRD2 rs6275 polymorphism was noticed. DBH rs7239728 imparted significant risk at genotypic, allelic and carrier analyses. We identified a risk haplotype in DRD2 loci. Two genotype interactions between ANKK1rs1800497 and DBHrs72393728 polymorphisms showed significant risks. The variant gene product of ANKK1 rs1800497 was predicted with decreased aggregation of ANKK1 protein. In conclusion, we identified novel genetic variants, haplotype and gene interactions in dopaminergic pathway as potential risk factors for migraine susceptibility.

Potential role of aromatase over estrogen receptor gene polymorphisms in migraine susceptibility: a case control study from North India.

BACKGROUND: The present study was undertaken to find out the role of estrogen pathway related gene polymorphisms in susceptibility to migraine in Northern Indian population. Aromatase, CYP19A1 (rs10046 and rs4646); estrogen receptors, ESR1 (rs2234693, rs1801132, rs2228480 and rs9340799) and ESR2 (rs1271572 and rs1256049) polymorphisms were selected for the present study. METHODOLOGY/PRINCIPAL FINDINGS: The patients were recruited in two cohorts - primary (207) and replicative (127) along with 200 healthy controls and genotyped for various polymorphisms. Logistic regression analysis was applied for statistical analyses. The results were validated in the replicative cohort and pooled by meta analysis using Fisher's and Mantel-Haenszel test. Furthermore, Benjamini - Hochberg false discovery rate test was used to correct for multiple comparisons. CYP19A1 rs10046 and CYP19A1 rs4646 polymorphisms were found to confer risk and protective effect, respectively. Out of four ESR1 polymorphisms, only rs2234693 variant allele was significantly associated in migraine with aura. No significant associations were observed for ESR2 polymorphisms. Significant haplotypes were identified for CYP19A1 and ESR1 polymorphisms. Gene- gene interactions of genotypes as well as haplotypes were observed for CYP19A1- ESR1 showing both risk and protective combinations. CONCLUSION: We strongly suggest CYP19A1 polymorphisms to be the major contributing factors in migraine susceptibility instead of genetic variants of estrogen receptors.

Role of dopaminergic gene polymorphisms (DBH 19 bp indel and DRD2 Nco I) in genetic susceptibility to migraine in North Indian population.

OBJECTIVE: The dopaminergic system plays a major role in migraine. We aimed to look for association of polymorphisms in dopaminergic genes in genetic susceptibility to migraine in North Indian population. In the present study, two polymorphisms, DBH 19 bp indel (rs no. 72393728) and DRD2 Nco I (rs no. 6275), were selected. DESIGN: Using case-control design, 301 migraine patients (202 migraine without aura and 99 migraine with aura) and 202 healthy controls were recruited in the study. Genotyping was done using polymerase chain reaction (PCR) (DBH 19 bp indel) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) (DRD2 Nco I). Logistic regression analysis was used to find the contribution of these polymorphisms in migraine. Bonferroni's correction was applied for multiple comparisons. RESULTS: In DBH 19 bp indel polymorphism, a significant association was observed at allelic level (P = 0.027) especially in females (P = 0.016) on comparing migraine patients with healthy controls. In DRD2 Nco I polymorphism, no significant association was observed in migraine patients or any subgroups. CONCLUSION: Our study suggests a potentially significant role of DBH 19 bp indel polymorphism in migraine susceptibility.

Investigation of TNFA 308G > A and TNFB 252G > A polymorphisms in genetic susceptibility to migraine.

We aimed to look for the association of tumor necrosis factor (TNF) gene polymorphisms (TNFA 308G > A, and TNFB 252G > A) in genetic susceptibility to migraine. The pathogenesis of migraine involves many immune-mediated mechanisms in the vascular endothelium. TNF, being a potent immunomodulator and pro-inflammatory cytokine, is suggested to be involved in inflammatory reactions leading to migraine attacks. A total of 216 normotensive migraine patients, 160 tension type headache (TTH) patients and 216 healthy controls (HC) were recruited in the study. The genetic polymorphisms were investigated through SNP association analysis using a matched case control migraine population. Genotyping of TNFA 308G > A polymorphism and TNFB 252G > A was done using ARMS PCR and PCR-RFLP, respectively. A borderline association was observed in TNFA 308GA genotype in migraine patients versus HC (p = 0.043; OR = 1.763; 95% CI = 1.019-3.051). After sub-grouping migraine into migraine with aura (MA) or without aura, significant difference at genotypic (p = 0.015; OR = 2.293; 95% CI = 1.172-4.487) as well as allelic (p = 0.035; OR = 1.955; 95% CI = 1.047-3.651) level was evident. The difference was even more significant in female MA at genotypic (p = 0.006; OR = 2.901; 95% CI = 1.361-6.181) and allelic level (p = 0.017; OR = 2.318; 95% CI = 1.159-4.635) as well as for A allele carriers in MA [p value = 0.020; OR = 2.205 (1.132-4.295)] and female MA (p value = 0.008; OR = 2.741; CI = 1.297-5.792). No association of TNFB252G > A was observed in migraine patients or any subgroups. We did not find any association of TNFA or TNFB gene polymorphisms with TTH. In conclusion, the TNFA 308G > A polymorphism was found to be associated with MA, particularly in females, whereas we could not find any association of TNFB 252G > A polymorphism in genetic susceptibility to migraine on comparing the migraine patients with HC or TTH patients.