Diabetes mellitus is growing at an alarming rate globally. My dissertation aims at understanding the epigenetic mechanisms of Diabetes pathogenesis and how we can utilize this knowledge to develop treatments for patients with this debilitating disease.

Diabetes is associated with loss of pancreatic beta cells and islet replacement therapy is limited by the source of donor islets. Two promising alternative approaches for beta cell replenishment are regeneration of endogenous beta cells and directed stem cell differentiation. In chapter 1, I used a transgenic mouse model that ectopically expresses Ezh2, to offset the loss of endogenous protein and uncovered new insights into plasticity of beta cell regeneration in adulthood. I show that reprogramming of the Ink4a chromatin by modulating the conserved Polycomb-Trithorax mechanism can rejuvenate the replication capacity of aged beta cells to provide a new strategy for beta cell expansion. In chapter 2, I studied mouse embryonic stem (ES) cells to understand endodermal lineage specification, as current attempts to bring endoderm-derived stem cell therapy to a state of effectiveness have been hampered by the paucity of knowledge of the underlying mechanisms. I show that the pluripotency transcription factors and epigenetic modifications of the chromatin interact in order to implement control pathways that drive differentiation of stem cells towards the definitive endoderm lineage.

Type 1 Diabetes is caused by autoimmune assault of pathogenic T cells escaping the tolerance selection. In Chapter 3, I identified a novel interaction partner of the autoimmune regulator (Aire), JmjD6. My data suggest that JmjD6-mediated histone demethylation at Arginine 2 residues of target chromatin is essential to prime the chromatin of otherwise repressed peripheral tissue antigen (PTA), for subsequent Aire activation of the antigen peptides for tolerance selection.

Maternal obesity is concerning because of the deleterious effects in offspring of increased risks of metabolic syndromes including Type 2 diabetes and obesity. My current work is focused on whole genome methylation mapping of trans-generational epigenetic inheritance in a maternal high-fat diet mouse model. The single nucleotide resolution of this screening will reveal information on how inherited methylation markers contribute to the predisposition of metabolic diseases in progeny in the context of maternal obesity, which can be further utilized for intervention and disease prevention.

Vehicles following each other in close-proximity in the form of a platoon reduce fuel consumption due to reduction in air drag saving up to 5% for the first vehicle and 10% for the following vehicles. Introduction of vehicle-to-vehicle communication has led to further decrease in inter-vehicular spacing, enabling further reduction in fuel consumption and improving the road capacity by up to 166%. Dynamic platoon formation and dissolution is generally governed by the lead vehicle, leading to a centralized approach. This suffers from various drawbacks such as single point of failure and performance bottlenecks resulting in serialization of maneuvers and shorter platoon length. A decentralized approach mitigates these issues and is traditionally realized using the "top-down" approach by first identifying the maneuvers and then executing the required steps and exchanging the necessary messages. Such decentralized platooning systems, which are known as “Deliberate Platooning”, suffer from higher complexity and reduced flexibility. This dissertation presents ADEPT – Adaptive Decentralized Emergent-behavior based PlaTooning, that aims at mitigating the shortcomings of "traditional" decentralized platooning systems. ADEPT uses a novel decentralized automated vehicle platooning approach inspired by nature's "emergent behavior” commonly found in biological systems. In ADEPT, each vehicle follows a set of simple rules when they need to interact in order to carry out the maneuvers. Platooning maneuvers such as join, exit, and merge “emerge” as a result of vehicles following these “emergent rules”. Through extensive simulation experiments using a platooning-enabled vehicular network simulator driven by a wide range of scenarios, we demonstrate that ADEPT yields superior performance in terms of maneuver time and communication overhead, especially in multi-vehicle multi-maneuver scenarios. Additionally, we devise mechanisms for obstacle avoidance, vehicle following, gap- and predecessor determination on curved roads and, using a well-known simulation environment equipped with a physics engine, demonstrate that our emergent platooning approach is effective when vehicle characteristics such as weight, center of mass and friction are considered.

An important aim of Type I diabetes therapeutic strategies is the replenishment of functional beta cells. Directing the efficient differentiation of stem cell sources in vitro into functional insulin secreting beta cells is the preferred approach, however, existing experimental protocols have not been able to successfully yield functionally responsive insulin positive cells. One obstacle in this approach can be attributed to gaps in the understanding of mechanisms that regulate pancreatic beta cell development in vivo. This research work seeks to better understand the mechanisms by which important genetic and epigenetic regulators govern pancreatic cell fate specification and maintenance.

Our data reveals that microRNAs (miRNAs) - post-transcriptional regulators of gene expression - play an important role in the functional maintenance and survival of newly specified pancreatic beta cells. In the absence of the miRNA-processing enzyme Dicer1, newly specified beta cells lose insulin expression and acquire a neuronal transcriptional profile. The deregulation of neuronal genes is associated with a loss of binding of the neuronal transcriptional repressor REST to its neuronal target genes. This suggests that miRNAs play an important role in modulating critical regulators of cell fate during pancreatic islet cell development.

Interestingly, an investigation into a role for REST during early pancreatic development revealed that activation of REST target genes in pancreatic progenitors resulted in the epithelium adopting a progenitor and duct-like state with defects in endocrine and acinar cell specification. This data argues for a previously unknown role for REST in modulating pancreatic organogenesis.

In addition to discovering novel transcriptional regulators of pancreatic development, our data provides insights into a critical role for a DNA methyltransferase - DNMT1 - in coordinating pancreatic organogenesis. Abrogation of DNMT1 expression in pancreatic progenitors resulted in p53-dependant apoptosis of the progenitors that was subsequently rescued upon introduction of p53 haploinsufficiency to the DNMT1 deficient progenitors.

This body of work adds to the overall understanding of normal embryonic pancreas development and may guide the creation of efficient beta cell differentiation protocols allowing for in vitro differentiated beta cells to possibly become an important source for replenishing beta cells in diabetic patients