Our previous studies demonstrated that the regulation of the DNA methylation pattern involves the poly(ADP-ribosyl)ation (PARylation) process, a post-translational modification of proteins catalysed by the poly(ADP-ribose) polymerase (PARP) enzymes. DNA methylation can influence the genetic susceptibility to type 2 diabetes mellitus (T2DM) and the progression of the disease. We have recently shown that the PARylation process is over-activated in patients with T2DM, particularly in those with poor glycaemic control. In PBMC from diabetic patients, PARylation was found to be linked to dysregulation of DNA methylation pattern via activation of the DNA de-methylation cascade.
In the present project, we aim to test if the observed changes in DNA methylation pattern are effectively induced by PARP-1 over-activation in T2DM and if this interplay may be driven by a common element: prolonged increases in reactive oxygen species (ROS) production, key factors in the pathogenesis of T2DM and obesity-related diseases. For this reason, we will use cultured cells exposed to high glucose as a valuable tool for defining the role of PARylation in the DNA methylation process by modulating its activity through specific inhibitors and silencing of PARP enzymes. As ROS production has been reported to stimulate PARP activity in response to high glucose, we aim to understand if enhanced intracellular glucose transport can lead to ROS overproduction and subsequent PARP activation by monitoring the production of ROS in our cellar system.
Further step will be to measure the oxidative status of both PBMC and plasma in subjects affected by T2DM and see how it correlates with PARylation/ DNA demethylation interplay.
The understanding of the DNA methylation/de-methylation mechanism is important, since restoring the control of DNA de-methylation cycle promises beneficial effects. In this context, the use of PARP inhibitors may be therapeutically relevant.
