Glucokinase (GK) deficiency can drive maturity-onset diabetes of the young (GCK-MODY) in heterozygotes and permanent neonatal diabetes in homozygotes. We describe a hypomorphic Gck allele that results in aberrant splicing in islets and liver lowering GK activity by ∼85%. Whereas heterozygous mutant mice are mildly hyperglycemic, homozygotes have frank diabetes but survive to adulthood. Dorzagliatin potentiates the effects of glucagon-like receptor-1 receptor activation sex dependently in heterozygous Gck mice and in obese hyperglycemic db/db mice. Combined use of these drugs may be useful in some forms of GCK-MODY and in obesity-related type 2 diabetes.

Neonatal transfer of immature dendritic cell-enriched Flt3L splenocytes significantly reduces the incidence of type 1 diabetes in female NOD mice. Early time points are associated with accumulation of anergic T cells. In adult mice, there is a reduction in CD4 T helper 1 cells and reduced proliferation and perforin of CD8 T cells. Our work demonstrates how targeting the neonatal window of tolerance alters autoimmunity outcome.

Activated neutrophils kill retinal endothelial cells (ECs) in early diabetic retinopathy, but how neutrophils become activated in diabetes is not well understood. We found that lysyl oxidase (LOX), whose matrix-localized form activates retinal ECs, can also directly activate neutrophils in its soluble form. LOX-induced release of neutrophil elastase and superoxide is mediated by actin remodeling and membrane aggregation of azurophilic granules. The dual ability of LOX to activate neutrophils (in its soluble form) and retinal ECs (in its matrix-localized form) implicates it as a key proinflammatory target for early diabetic retinopathy.

The control of muscle glucose uptake (MGU) is distributed across delivery, transport, and phosphorylation of glucose. These steps have been defined as control points of MGU invivo due to the application of isotopic tracer techniques to transgenic mouse models. Using these techniques in a classic study published in Diabetes, Fueger etal. demonstrated that overexpression in skeletal muscle of hexokinase II (HKII), the enzyme responsible for intracellular glucose phosphorylation, enhanced MGU in insulin-sensitive but not in insulin-resistant mice. Conversely, HKII overexpression enhanced MGU in insulin-resistant mice in response to exercise. Since exercise reduces barriers of glucose delivery and transport, this suggested that these two processes contribute to the dysregulation of MGU in insulin-resistant states. These fundamental findings have spurred subsequent studies highlighting the contribution of glucose delivery and transport to the regulation of MGU in health and disease.

Individuals with low birth weight (LBW) are at increased risk of type 2 diabetes. Four weeks of carbohydrate overfeeding (COF) was associated with differential elevations in fasting glucose, lipids, alanine, insulin resistance, and resting energy expenditure in LBW participants versus control participants. Multiomics analyses indicated reduced peroxisome proliferator-activated receptor signaling, as well as differential expression of genes involved in collagen and extracellular matrix metabolism in LBW participants during COF. Interestingly, the COF perturbations in LBW participants became more pronounced when excluding five LBW men with screen-detected metabolic dysfunction-associated steatotic liver disease. The findings support the notion of unhealthy subcutaneous adipose tissue expandability potentially underlying a reduced metabolic buffering capacity in nonobese LBW men.