Reading between the (Genetic) Lines: How Epigenetics is Unlocking Novel Therapies for Type 1 Diabetes

Metaboloepigenetics in cancer, immunity and cardiovascular disease

The influence of cellular metabolism on epigenetic pathways are well documented but misunderstood. Scientists have long known of the metabolic impact on epigenetic determinants. More often than not, that title role for DNA methylation was portrayed by the metabolite SAM or S-adenosylmethionine. Technically speaking there are many other metabolites that drive epigenetic processes that instruct seemingly distant - yet highly connect pathways - and none more so than our understanding of the cancer epigenome. Recent studies have shown that available energy link the extracellular environment to influence cellular responses. This focused review examines the recent interest in epigenomics and casts cancer, metabolism and immunity in unfamiliar roles - cooperating. There are not only language lessons from cancer research, we have come round to appreciate that reaching into areas previously thought of as too distinct are also object lessons in understanding health and disease. The Warburg effect is one such signature of how glycolysis influences metabolic shift during oncogenesis. That shift in metabolism - now recognised as central to proliferation in cancer biology - influence core enzymes that not only control gene expression but are also central to replication, condensation and the repair of nucleic acid. These nuclear processes rely on metabolism and with glucose at center stage the role of respiration and oxidative metabolism are now synonymous with the mitochondria as the powerhouses of metaboloepigenetics. The emerging evidence for metaboloepigenetics in trained innate immunity has revealed recognisable signalling pathways with antecedent extracellular stimulation. With due consideration to immunometabolism we discuss the striking signalling similarities influencing these core pathways. The immunometabolic-epigenetic axis in cardiovascular disease has deeply etched connections with inflammation and we examine the chromatin template as a carrier of epigenetic indices that determine the expression of genes influencing atherosclerosis and vascular complications of diabetes.

Antioxidant, Anti-Inflammatory, and Immunomodulatory Properties of Tea-The Positive Impact of Tea Consumption on Patients with Autoimmune Diabetes

The physiological markers of autoimmune diabetes include functional disorders of the antioxidative system as well as progressing inflammation and the presence of autoantibodies. Even though people with type 1 diabetes show genetic predispositions facilitating the onset of the disease, it is believed that dietary factors can stimulate the initiation and progression of the disease. This paper analyses the possibility of using tea as an element of diet therapy in the treatment of type 1 diabetes. Based on information available in literature covering the last 10 years, the impact of regular tea consumption or diet supplements containing tea polyphenols on the oxidative status as well as inflammatory and autoimmune response of the organism was analyzed. Studies conducted on laboratory animals, human patients, and in vitro revealed positive effects of the consumption of tea or polyphenols isolated therefrom on the diabetic body. Few reports available in the literature pertain to the impact of tea on organisms affected by type 1 diabetes as most (over 85%) have focused on cases of type 2 diabetes. It has been concluded that by introducing tea into the diet, it is possible to alleviate some of the consequences of oxidative stress and inflammation, thus limiting their destructive impact on the patients' organisms, consequently improving their quality of life, regardless of the type of diabetes. Furthermore, elimination of inflammation should reduce the incidence of immune response. One should consider more widespread promotion of tea consumption by individuals genetically predisposed to diabetes, especially considering the drink's low price, easy availability, overall benefits to human health, and above all, the fact that it can be safely used over extended periods of time, regardless of the patient's age.

Glucose Variability: How Does It Work?

A growing body of evidence points to the role of glucose variability (GV) in the development of the microvascular and macrovascular complications of diabetes. In this review, we summarize data on GV-induced biochemical, cellular and molecular events involved in the pathogenesis of diabetic complications. Current data indicate that the deteriorating effect of GV on target organs can be realized through oxidative stress, glycation, chronic low-grade inflammation, endothelial dysfunction, platelet activation, impaired angiogenesis and renal fibrosis. The effects of GV on oxidative stress, inflammation, endothelial dysfunction and hypercoagulability could be aggravated by hypoglycemia, associated with high GV. Oscillating hyperglycemia contributes to beta cell dysfunction, which leads to a further increase in GV and completes the vicious circle. In cells, the GV-induced cytotoxic effect includes mitochondrial dysfunction, endoplasmic reticulum stress and disturbances in autophagic flux, which are accompanied by reduced viability, activation of apoptosis and abnormalities in cell proliferation. These effects are realized through the up- and down-regulation of a large number of genes and the activity of signaling pathways such as PI3K/Akt, NF-κB, MAPK (ERK), JNK and TGF-β/Smad. Epigenetic modifications mediate the postponed effects of glucose fluctuations. The multiple deteriorative effects of GV provide further support for considering it as a therapeutic target in diabetes.

Diagnosis and treatment of type 1 diabetes at the dawn of the personalized medicine era

Type 1 diabetes affects millions of people globally and requires careful management to avoid serious long-term complications, including heart and kidney disease, stroke, and loss of sight. The type 1 diabetes patient cohort is highly heterogeneous, with individuals presenting with disease at different stages and severities, arising from distinct etiologies, and overlaying varied genetic backgrounds. At present, the “one-size-fits-all” treatment for type 1 diabetes is exogenic insulin substitution therapy, but this approach fails to achieve optimal blood glucose control in many individuals. With advances in our understanding of early-stage diabetes development, diabetes stratification, and the role of genetics, type 1 diabetes is a promising candidate for a personalized medicine approach, which aims to apply “the right therapy at the right time, to the right patient”. In the case of type 1 diabetes, great efforts are now being focused on risk stratification for diabetes development to enable pre-clinical detection, and the application of treatments such as gene therapy, to prevent pancreatic destruction in a sub-set of patients. Alongside this, breakthroughs in stem cell therapies hold great promise for the regeneration of pancreatic tissues in some individuals. Here we review the recent initiatives in the field of personalized medicine for type 1 diabetes, including the latest discoveries in stem cell and gene therapy for the disease, and current obstacles that must be overcome before the dream of personalized medicine for all type 1 diabetes patients can be realized.

Polymorphisms in canine immunoglobulin heavy chain gene cluster: a double-edged sword for diabetes mellitus in the dog

Insulin deficiency diabetes (IDD) in dogs is an endocrine disease similar to human type 1 diabetes. There are breeds more commonly affected, such as Yorkshire Terrier and Samoyed, suggesting an underlying genetic component. However, the genetic basis for canine diabetes mellitus (DM) is not fully established. We conducted both whole-genome scans for selection signatures and GWASs to compare the genomes of 136 dogs belonging to 29 breeds previously described at low or high risk for developing DM. Candidate variants were tested in dogs with a diagnosis of IDD and controls attending the Complutense Veterinary Teaching Hospital. The only genomic region under selection (CFA8:72 700 000-74 600 000; CanFam3.1) retrieved by our analyses is included in the immunoglobulin heavy chain gene cluster, which has already been related to human human type 1 diabetes susceptibility. This region contains two non-synonymous variants, rs852072969 and rs851728071, showing significant associations with high or low risk for IDD, respectively. The first variant, rs852072969, alters a protein poorly characterised in the dog. In contrast, rs851728071 was predicted to block the synthesis of an immunoglobulin variable (V) domain in breeds at low risk for DM. Although a large and diverse V gene repertoire is thought to offer a fitness advantage, we suggest that rs851728071 prevents the formation of an auto-reactive immunoglobulin V domain probably involved in the pathophysiology of IDD and, thus, decreases the risk for the disease. These results should be interpreted with caution until the functional roles of the proposed variants have been proved in larger studies.