Although the exact etiology of inflammatory bowel disease(IBD)remains unclear,exaggerated immune response in genetically predisposed individuals has been reported.Th1 and Th17 cells mediate IBD development.Macrophages produce IL-12 and IL-23 that share p40 subunit encoded by IL12B gene as heteromer partner to drive Th1 and Th17 differentiation.The available animal and human data strongly support the pathogenic role of IL-12/IL-23 in IBD development and suggest that blocking p40 might be the potential strategy for IBD treatment.Furthermore,aberrant alteration of some cytokines expression via epigenetic mechanisms is involved in pathogenesis o f IBD.In this study,we analyzed core promoter region of IL12B gene and investigated whether IL12B expression could be regulated through targeted epigenetic modification with gene editing technology.Transcription activator-like effectors(TALEs)are widely used in the field of genome editing and can specifically target DNA sequence in the host genome.We synthesized the TALE DNA-binding domains that target the promoter of human IL12B gene and fused it with the functional catalytic domains of epigenetic enzymes.Transient expression of these engineered enzymes demonstrated that the TALE-DNMT3A targeted the selected IL12B promoter region,induced loci-specific DNA methylation,and down-regulated IL-12B expression in various human cell lines.Collectively,our data suggested that epigenetic editing of IL12B through methylating DNA on its promoter might be developed as a potential therapeutic strategy for IBD treatment.
Meng CHENHua ZHUYu-juan MAONan CAOYa-li YULian-yun LIQiu ZHAOMin WUMei YE
