Periodic Reporting for period 1 - EPIRIN (EPIGENETIC REGULATION OF INFLAMMATION IN NAFLD)
Reporting period: 2015-05-01 to 2017-04-30
Main results: Exploring histone modifications regulating inflammatory characteristics of immune cells in fatty liver disease. Lymphocytes are recruited to injured liver by inflammatory signals such as chemokines. Additionally, secreted mediators (cytokines and adipokines) from hepatocytes, adipocytes and gut can potentially direct inflammatory cells through the site of injury. To examine the hypothesis “lymphocytes are epigenetically programmed into inflammatory state in NASH”, firstly transcriptional features of lymphocytes in NAFLD were examined. Isolated NK and NKT cells from animal models and NAFLD patients were analysed by qRT-PCR. Expression profiling targeted inflammatory cytokines including TNF-α, IL-1β, IL-6, IL-10, IL-13, IL-17, significant increases were detected in TNF-α and IL-1β. Additional array studies array studies demonstrated novel inflammatory markers on Natural killer cells which possibly play a role in gaining of inflammatory characteristics presented by peripheral and intrahepatic NK and NKT cells. We also detected major gene expression differences between peripheral (blood) and intrahepatic (liver) NK/NKT cells in NASH. To determine the importance of histone marks in controlling inflammatory features of lymphocytes: We examined the role of histone modifications controlling inflammatory characteristics of NK and NKT cells. It was hypothesized that several histone modifications are altered in either pre-NASH state or progression. Chip-Sequencing were employed to identify stable histone-DNA interactions which revealed that immune cells (NK or NKT cells) demonstrate unique histone alterations in progression from steatosis to non-alcoholic steatohepatitis. Elucidating the role of DNA methylation in the regulation of NK and NKT cells in NASH
To discover how CpG methylation regulates inflammatory phenotype at transcriptional level; DNA methylation and transcriptional repression were investigated in NK/NKT cells. Arrays were employed to investigate methylated cytosines. Validation was performed by loci-specific bisulfite sequencing and pyrosequencing. We found new hepatic and circulating NK cell metylation markers which was strongly linked with NK cell phenotype in steatohepatitis.