Folate metabolic pathway single nucleotide polymorphisms: a predictive pharmacogenetic marker of methotrexate response in Indian (Asian) patients with rheumatoid arthritis.

AIM: We evaluated the pharmacogenetic influence of genetic polymorphisms in folate pathway genes in Indian rheumatoid arthritis patients receiving methotrexate (MTX). PATIENTS & METHODS: Twelve polymorphisms within nine folate pathway genes were analyzed for association with MTX response in 322 Indian rheumatoid arthritis (RA) patients and MTX pharmacokinetics in 94 RA patients. RESULTS: Polymorphisms in GGH, SHMT1 and TS were associated with MTX-related adverse events while SNPs in MTHFR and RFC1/SLC19A1 were associated with MTX efficacy. TS5'UTR and SHMT1 polymorphisms were associated with higher plasma levels of MTX. CONCLUSION: Polymorphisms in folate-MTX pathway genes contribute to MTX response and affect MTX concentrations in Indian RA patients. A toxicogenetic index could identify patients who develop adverse events to MTX.

Genome-wide analysis correlates Ayurveda Prakriti.

The practice of Ayurveda, the traditional medicine of India, is based on the concept of three major constitutional types (Vata, Pitta and Kapha) defined as "Prakriti". To the best of our knowledge, no study has convincingly correlated genomic variations with the classification of Prakriti. In the present study, we performed genome-wide SNP (single nucleotide polymorphism) analysis (Affymetrix, 6.0) of 262 well-classified male individuals (after screening 3416 subjects) belonging to three Prakritis. We found 52 SNPs (p ≤ 1 × 10(-5)) were significantly different between Prakritis, without any confounding effect of stratification, after 10(6) permutations. Principal component analysis (PCA) of these SNPs classified 262 individuals into their respective groups (Vata, Pitta and Kapha) irrespective of their ancestry, which represent its power in categorization. We further validated our finding with 297 Indian population samples with known ancestry. Subsequently, we found that PGM1 correlates with phenotype of Pitta as described in the ancient text of Caraka Samhita, suggesting that the phenotypic classification of India's traditional medicine has a genetic basis; and its Prakriti-based practice in vogue for many centuries resonates with personalized medicine.

DNA methylation analysis of phenotype specific stratified Indian population.

BACKGROUND: DNA methylation and its perturbations are an established attribute to a wide spectrum of phenotypic variations and disease conditions. Indian traditional system practices personalized medicine through indigenous concept of distinctly descriptive physiological, psychological and anatomical features known as prakriti. Here we attempted to establish DNA methylation differences in these three prakriti phenotypes. METHODS: Following structured and objective measurement of 3416 subjects, whole blood DNA of 147 healthy male individuals belonging to defined prakriti (Vata, Pitta and Kapha) between the age group of 20-30years were subjected to methylated DNA immunoprecipitation (MeDIP) and microarray analysis. After data analysis, prakriti specific signatures were validated through bisulfite DNA sequencing. RESULTS: Differentially methylated regions in CpG islands and shores were significantly enriched in promoters/UTRs and gene body regions. Phenotypes characterized by higher metabolism (Pitta prakriti) in individuals showed distinct promoter (34) and gene body methylation (204), followed by Vata prakriti which correlates to motion showed DNA methylation in 52 promoters and 139 CpG islands and finally individuals with structural attributes (Kapha prakriti) with 23 and 19 promoters and CpG islands respectively. Bisulfite DNA sequencing of prakriti specific multiple CpG sites in promoters and 5'-UTR such as; LHX1 (Vata prakriti), SOX11 (Pitta prakriti) and CDH22 (Kapha prakriti) were validated. Kapha prakriti specific CDH22 5'-UTR CpG methylation was also found to be associated with higher body mass index (BMI). CONCLUSION: Differential DNA methylation signatures in three distinct prakriti phenotypes demonstrate the epigenetic basis of Indian traditional human classification which may have relevance to personalized medicine.

Profiling single nucleotide polymorphisms (SNPs) across intracellular folate metabolic pathway in healthy Indians.

BACKGROUND & OBJECTIVES: Many pharmacologically-relevant polymorphisms show variability among different populations. Though limited, data from Caucasian subjects have reported several single nucleotide polymorphism (SNPs) in folate biosynthetic pathway. These SNPs may be subjected to racial and ethnic differences. We carried out a study to determine the allelic frequencies of these SNPs in an Indian ethnic population. METHODS: Whole blood samples were withdrawn from 144 unrelated healthy subjects from west India. DNA was extracted and genotyping was performed using PCR-RFLP and Real-time Taqman allelic discrimination for 12 polymorphisms in 9 genes of folate-methotrexate (MTX) metabolism. RESULTS: Allele frequencies were obtained for MTHFR 677T (10%) and 1298 C (30%), TS 3UTR 0bp (46%), MDR1 3435T and 1236T (62%), RFC1 80A (57%), GGH 401T (61%), MS 2756G (34%), ATIC 347G (52%) and SHMT1 1420T (80%) in healthy subjects (frequency of underlined SNPs were different from published study data of European and African populations). INTERPRETATION & CONCLUSIONS: The current study describes the distribution of folate biosynthetic pathway SNPs in healthy Indians and validates the previous finding of differences due to race and ethnicity. Our results pave way to study the pharmacogenomics of MTX in the Indian population.

Traditional medicine and genomics.

'Omics' developments in the form of genomics, proteomics and metabolomics have increased the impetus of traditional medicine research. Studies exploring the genomic, proteomic and metabolomic basis of human constitutional types based on Ayurveda and other systems of oriental medicine are becoming popular. Such studies remain important to developing better understanding of human variations and individual differences. Countries like India, Korea, China and Japan are investing in research on evidence-based traditional medicines and scientific validation of fundamental principles. This review provides an account of studies addressing relationships between traditional medicine and genomics.

Genetic polymorphism of CYP2C19 in Maharashtrian population.

Inter-individual variability in drug response is well known. Genetic polymorphism in genes encoding drug-metabolizing enzymes results in variation in drug metabolism and in turn drug response. The cytochrome P450 enzymes (CYP) play a central role in the metabolism of many therapeutic agents. CYP2C19 gene polymorphism is widely studied in Caucasians, African, and Oriental populations; however, far less is known about other ethnic groups such as Indians. Indian population is an inter-mixture of the Aryan, Dravidian, Kolarain, and the Mongoloid races. CYP2C19 gene polymorphism is reported in North Indian and South Indian populations yet not much is known about Maharashtrian population of Australoid-Europoid origin residing in Western India. This is the first report on CYP2C19 allele and genotype frequencies in Maharashtrian population. In this study, genotypes of major allelic variants of CYP2C19 gene in 139 unrelated healthy Maharashtrian subjects was determined and their frequencies were compared with previously studied Indian and other populations. Meta-analysis revealed that the study population is distinct from Caucasians, Africans and some of the Asian populations and significant heterogeneity exists among Indian subpopulations.

Presence of two types of flowers with respect to nectar sugar in two gregariously flowering species.

Many species of animal-pollinated flowers are known to vary widely in the nectar content of flowers. Some proportion of flowers in many species is apparently nectarless,and such flowers are believed to be 'cheaters'. Cheating may explain a part of the variability in nectar content.If cheating exists as a qualitatively different strategy then we expect bimodality in the distribution of nectar content of flowers. It has been shown in a multispecies study that gregarious species have a higher proportion of cheater flowers. We studied the frequency distribution of total nectar sugar in two gregariously flowering species Lantana camara and Utricularia purpurascens, which differed in other floral and ecological characters. At the population level, both the species showed significant bimodality in the total sugar content of flowers. The obvious sources of heterogeneity in the data did not explain bimodality. In Lantana camara, bimodality was observed within flowers of some of the individual plants sampled. In Utricularia purpurascens the proportion of nectarless flowers was more in high-density patches, suggesting that the gregariousness hypothesis may work within a species as well. The results support the hypothesis of cheating as a distinct strategy since two distinct types of flowers were observed in both the species. The effect of density in Utricularia purpurascens also supports the gregariousness hypothesis.