Although the developing pancreas is exquisitely sensitive to nutrient supply in utero, it is not entirely clear how nutrient-driven posttranslational modification of proteins impacts the pancreas during development. We hypothesized that the nutrient-sensing enzyme O-GlcNAc transferase (Ogt), which catalyzes an O-GlcNAc-modification onto key target proteins, integrates nutrient-signaling networks to regulate cell survival and development. In this study, we investigated the heretofore unknown role of Ogt in exocrine and endocrine islet development. By genetic manipulation in vivo and by using morphometric and molecular analyses, such as immunofluorescence imaging and single cell RNA sequencing, we show the first evidence that Ogt regulates pancreas development. Genetic deletion of Ogt in the pancreatic epithelium (OgtKO Panc) causes pancreatic hypoplasia, in part by increased apoptosis and reduced levels of of Pdx1 protein. Transcriptomic analysis of single cell and bulk RNA sequencing uncovered cell-type heterogeneity and predicted upstream regulator proteins that mediate cell survival, including Pdx1, Ptf1a and p53, which are putative Ogt targets. In conclusion, these findings underscore the requirement of O-GlcNAcylation during pancreas development and show that Ogt is essential for pancreatic progenitor survival, providing a novel mechanistic link between nutrients and pancreas development.

Fetal growth restriction, or low birthweight is a strong determinant for eventual obesity and Type 2 diabetes. Clinical studies suggest placental mechanistic target of rapamycin (mTOR) signaling regulate fetal birthweight and the metabolic health trajectory of the offspring. In the current study, we used genetic model with loss of placental mTOR function (mTORKO Placenta ) to test the direct role of mTOR signaling on birthweight and the metabolic health in the adult offspring. mTORKO Placenta animals displayed reduced placental area and total weight, as well as fetal bodyweight at embryonic day (e) 17.5. Birthweight and serum insulin levels were reduced; however, β-cell mass was normal in mTORKO Placenta newborns. Adult mTORKO Placenta offspring, under a metabolic high-fat challenge, displayed exacerbated obesity and metabolic dysfunction compared to littermate controls. Subsequently, we tested whether enhancing placental mTOR complex 1 (mTORC1) signaling, via genetic ablation of TSC2, in utero would improve glucose homeostasis in the offspring. Indeed, increased placental mTORC1 conferred protection from a diet-induced obesity in the offspring. In conclusion, placental mTORC1 serves as a mechanistic link between placental function and programming of obesity and insulin resistance in the adult offspring.

The importance of sexual dimorphism has been highlighted in recent years since the National Institutes of Health’s mandate on considering sex as a biological variable. While recent studies have taken strides to study both sexes side by side, investigations into the normal physiological differences between males and females are limited. In this study, we aimed to characterized sex-dependent differences in glucose metabolism and pancreatic beta cell physiology in normal conditions using C57BL/6J mice, the most common mouse strain used in metabolic studies. Here we report that female mice have improved glucose and insulin tolerance associated with lower non-fasted blood glucose and insulin levels compared to male mice at 3 and 6 month of age. Both male and female animals show beta cell mass expansion from e17.5 to adulthood, and no sex differences were observed at e17.5, newborn, 1 month, or 3 months of age. However, 6-month old males displayed increased beta cell mass in response to insulin resistance compared to littermate females. Molecularly, we uncovered sexual dimorphic alterations in the protein levels of nutrient sensing proteins Ogt and mTOR, as well as differences in glucose-stimulus coupling mechanisms that may underlie the differences in sexually dimorphic beta cell physiology observed in C57BL/6J mice.

Background In contrast with the setting of acute myocardial infarction, there are limited data regarding the impact of diabetes mellitus on clinical outcomes in contemporary cohorts of patients with chronic coronary syndromes. We aimed to investigate the prevalence and prognostic impact of diabetes according to geographical regions and ethnicity. Methods and results CLARIFY is an observational registry of patients with chronic coronary syndromes, enrolled across 45 countries in Europe, Asia, America, Middle East, Australia, and Africa in 2009–2010, and followed up yearly for 5 years. Chronic coronary syndromes were defined by ≥1 of the following criteria: prior myocardial infarction, evidence of coronary stenosis >50%, proven symptomatic myocardial ischaemia, or prior revascularization procedure. Among 32 694 patients, 9502 (29%) had diabetes, with a regional prevalence ranging from below 20% in Northern Europe to ∼60% in the Gulf countries. In a multivariable-adjusted Cox proportional hazards model, diabetes was associated with increased risks for the primary outcome (cardiovascular death, myocardial infarction, or stroke) with an adjusted hazard ratio of 1.28 (95% confidence interval 1.18, 1.39) and for all secondary outcomes (all-cause and cardiovascular mortality, myocardial infarction, stroke, heart failure, and coronary revascularization). Differences on outcomes according to geography and ethnicity were modest. Conclusion In patients with chronic coronary syndromes, diabetes is independently associated with mortality and cardiovascular events, including heart failure, which is not accounted by demographics, prior medical history, left ventricular ejection fraction, or use of secondary prevention medication. This is observed across multiple geographic regions and ethnicities, despite marked disparities in the prevalence of diabetes. ClinicalTrials identifier ISRCTN43070564

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