Mohamed I. Husseiny El Sayed
Scientific Tracks Abstracts: J Diabetes Metab
Methylation of DNA is a mechanism by which cells control gene expression, and cell-specifi c genes oft en exhibit unique patterns of DNA methylation. We recently investigated the methylation pattern of the mouse insulin-2 gene (INS2) and found that there are 14 potential methylation (CpG) sites, all of which are unmethylated in insulinproducing cells but methylated in other tissues. Based on the hypothesis that damaged beta cells release their DNA into circulation, we aim to develop a sensitive and quantitative assay for circulating beta cell DNA for the detection of diabetes by methylation-specifi c polymerase chain reaction (MSP). Methylation-specifi c primers were designed based on the methylation of particular CpG sites in the gene using an approach to interrogate three or more CpG sites in the same assay. Th e cloned INS2 gene was unmethylated or methylated in vitro, representing insulin-producing and non-insulin-producing cells respectively, and then bisulfi tetreated and used in qPCR. We found that the production of PCR products depended on matching the 3�-terminus of the primers with unmethylated bisulfi te-treated template, while mismatches produced no product. Th e MSP method is sensitive and specifi c enough to diff erentiate between insulin-producing cells and other tissues as the MSP can detect as little as 2 copies per reaction and can detect 10 copies in the presence of genomic DNA background. Th ese results suggest that this MSP assay can be used for quantifi cation of circulating DNA from insulin-producing cells, which will provide the basis for developing assays to detect beta cell destruction in early diagnosis of type-1 diabetes mellitus.
Mohamed I. Husseiny El Sayed has completed his Ph.D at the age of 35 years from Friedrich-Alexander University, Erlangen-N?rnberg, Germany and postdoctoral studies from LA Biomed at Harbor-UCLA Medical Center, California, USA and Childrens Hospital Los Angeles, USC School of Medicine, California, USA. He is a postdoctoral fellow at the City of Hope, California, USA. He has published 14 papers in several reputed journals and serving as a reviewer for several peer-reviewed journals.
