TRAF6 bridges innate immune signaling to mitophagy to promote glucose control during metabolic stress.

Mitochondrial synthesis of adenosine triphosphate is essential for eukaryotic life but is dependent on the cooperation of two genomes: nuclear and mitochondrial DNA (mtDNA). mtDNA mutates ~15 times as...

TRAF6 bridges innate immune signaling to mitophagy to promote glucose control during metabolic stress.

Aims/hypothesis Pancreatic ductal adenocarcinoma-related diabetes mellitus (PDAC-DM) is a paraneoplastic syndrome with a poorly understood pathophysiology. PDAC-DM is often clinically confused with type 2 diabetes, resulting in delayed cancer detection and poorly individualised hyperglycaemia treatment. We investigated whether these forms of diabetes can be distinguished at the metabolic level. Methods Adults with either cancer treatment-naive PDAC-DM (n=28) or type 2 diabetes (n=97), and with diabetes onset within 3 years, underwent mixed-meal tolerance tests to investigate glucose metabolism. Outcomes included insulin sensitivity (Matsuda index), insulin secretion (insulinogenic index), beta cell function (oral disposition index), insulin clearance, and postprandial glucagon, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) responses. Results Compared with type 2 diabetes, individuals with PDAC-DM showed ~2.5-fold greater insulin sensitivity, ~81% lower insulin secretion and ~40% lower beta cell function. Insulin clearance was higher in the PDAC-DM group than the type 2 diabetes group, with and without adjustment for insulin sensitivity. Glucagon and GLP-1 levels increased after a meal in both groups, but levels were higher in the PDAC-DM group. GIP levels were similar between groups. The metabolic differences between groups persisted after adjustment for age, sex and BMI. Conclusions/interpretation PDAC-DM and type 2 diabetes are metabolically distinct, with different defects responsible for hyperglycaemia. PDAC-DM is characterised predominantly by insulin deficiency and displays higher insulin sensitivity than type 2 diabetes. There are also differences in alpha cell regulation and insulin clearance compared with type 2 diabetes. These findings identify biological characteristics that may have implications for individualised treatment of PDAC-DM and guide diagnostic biomarker discovery for early PDAC diagnosis. Graphical Abstract

α cells can generate and secrete both glucagon and GLP-1 with distinct processing enzymes to control metabolism.

Pancreatic cell types show changes in gene regulation and activity associated with T1D progression and risk.

Type 1 diabetes (T1D) is caused by the selective autoimmune ablation of pancreatic β-cells. Emerging evidence reveals β-cell secretory dysfunction arises e