Ground water Arsenic (As) toxicity is a global problem and millions of people are exposed to elevated levels (more than WHO advised maximum limit of 10µg/L) through drinking water. The exposure is associated with various cancerous and non-cancerous diseases. It may alter DNA methylation profiles of inviduals and suppress the activity of various genes giving rise to different diseases. Pakistan, a developing country in South Asian region, also has reported elevated ground water As levels in various investigations since 2005. However, a very limited biomonitoring studies have been conducted in this context while no study reports molecular changes associated with drinking water As exposure in Pakistan. Within this context, the present study aimed to investigate genome-wide DNA methylation profiles of the exposed subjects in two districts of Punjab Province Pakistan, i.e Lahore and Kasur. The population was stratified into three exposure groups comprising Low, Medium and High exposure based on their urinary arsenic levels. Genome-wide DNA methylation profiles were obtained using MeDIP in combination with NimbleGen 2.1M Deluxe Promotor arrays.
Freshly taken blood samples were collected form the respective exposure groups and transported in dry ice to Department of Toxicogenomics Maastricht University, The Netherlands for further analysis. DNA was isolated from buffy coats for performing global DNA methylation analysis using Methylated DNA immunoprecipitation (MeDIP-CHIP) on NimbleGen 2.1M Deluxe Promotors arrays (Roche, NimbleGen).