Epigenetics in Celiac Disease MEDICEL Istanbul 2012
Why this project? Epigenetics is the first level of integration of genetic and environmental factors. It may translate the effects of risk factors in terms of molecular events. It is feasable with the recent development of micro arrays/Si RNA knowledge. There is no data published to date on this topic (pubmed June 2012).
What is epigenetics? Epigenetics is the a way to transmit gene regulatory signals through mitosis. It is required for maintenance of cell differentiation. It is based on –DNA methylation –Histone acetylation and phosphorylation –RNA silencing
Histone acetylation
DNA methylation
RNA silencing
Epigenetics and complex diseases Epigenetics is the reflect of –Environmental factors –Stochastic events –Aging It is less stable than DNA variations but it is stable enough to explain chronic diseases. It may add to or reverse the effect of DNA variations explaining uncomplete penetrances. It may explain –Altered sex ratio in complex diseases –Incomplete concordance in monozygotic twins –Cancers Ptak et al. 2008
Epigenetics and inflammation Th1/Th2 ratio: –Methylation between IL-4 and IL-13 (5q21) reduces expression of Th2 –Th2 polarization increases methylation and decreases histone deacetylation of -IFN promoter IL-4/IL-13: –Demethylation + histone modification –Allowing GABA and STAT6 fixations –Lead to IL-4 synthesis that induces IL-13 and IL-15 FOXP3: –CpG motifs in promoter : methylted in naif and activated LT4 but demethylated in Treg. Lee. Immunity 2002 Jones EMBO J 2006
Epigenetics in lupus Thabet J Autoimmunol 12
Epigenetics in diabetes Keating J Cardiovasc Transl res 2012
Epidemic of celiac disease in children <2 years of age in Sweden Olsson. Pediatrics 2008
Fathers transmit preferrentially their DQ2 to their daughters 61% vs 42%, P=0.02 Megiorni.Am J Gastroenterol 2008
Study design 500 CD and 500 controls Data collection: –Clinical data –Environmental factors Biobanquing –Blood (stored at 20°C) –Intestinal biopsies (stored at -20°C). –Intestinal biopsies (stored at -80°C in RNA later) for few centres.
Procedures design Genetic profiling of participants for the 30 known CD polymorphisms. DNA methylation (Illumina 450k arrays) on blood and intestinal samples. RNA analyses (siRNA and functional validation of DNA methylation data for the most relevant genes). Biostatistics/ Mathematical modeling.
Main deliverables/perspectives A set of epigenetic biomarkers associated with the disease to be tested in prospective studies. A comprehensive model of gene/environment integration at the epigenetic level.
Shall we start? 500 euros / test Conditioning Transport : -20 ; -80°C Hypothesis of 15% difference : –800 patients – to euros