Aims/hypothesis The loss of pancreatic beta cell mass and identity is a hallmark of diabetes. While factors such as beta cell overwork (insulin hypersecretion) and elevated intracellular calcium have been implicated, beta cell identity loss also occurs in KATP gain-of-function (KATP-GOF) mice, a model of human neonatal diabetes, even in the absence of these factors. This suggests additional underlying mechanisms. Autophagy, a key process for cellular homeostasis, is impaired in the islets and beta cells of both type 1 and type 2 diabetes, but its role in monogenic diabetes with insulin secretory deficiency remains unclear. We hypothesise that autophagy dysfunction contributes to beta cell identity loss in KATP-GOF mice, and that intermittent fasting (IF) can restore autophagic flux, thereby preserving functional beta cell mass. Methods To test this, adult tamoxifen-inducible KATP-GOF mice and littermate controls were randomly assigned to two groups: (1) chow diet ad libitum; and (2) chow diet with alternate-day IF. Results KATP-GOF mice fed ad libitum developed severe hyperglycaemia due to impaired insulin secretion. This was followed by a reduction in insulin content, disruption of beta cell autophagic flux, autophagosome accumulation and, ultimately, the loss of beta cell identity and dedifferentiation. In contrast, KATP-GOF mice subjected to alternate-day IF exhibited lower blood glucose levels, improved mitochondrial morphology, restoration of autophagic flux and reestablishment of beta cell identity. Conclusions/interpretation This study provides the first evidence of autophagy impairment in non-obese, insulin secretory-deficient, KATP-induced diabetes mice and demonstrates that IF restores both autophagic flux and beta cell identity. This finding suggests that similar mechanisms may contribute to beta cell dysfunction in other forms of diabetes. Graphical Abstract

The authors highlight inconsistencies and divergencies in the literature reporting data on indirect calorimetry for studies on whole-body energy homeostasis, and propose harmonization of standards to facilitate data comparison and interpretation across different datasets.

Vancouver Coastal Health Research Institute — Leading innovative research with health impact in Canada. vchri.ca

Distinctively, pancreatic ductal adenocarcinoma (PDAC) consists of sparse tumour lesions intertwined with extensive desmoplastic stroma. The complexity of tumour-microenvironment interactions within this desmoplasia poses a challenge for accurate tumour profiling and patient stratification, and characterizes a profoundly chemoresistant tumour. Here we mapped the spatial relationships between tumour, stroma, and immune cell compartments delineating tumour and microenvironment types that expand the classical to basal spectrum of human PDAC. We used imaging mass cytometry to profile the in situ multi-cellular organization of 81 cell types in resected cases with paired whole genome sequencing. Cell types, functions, and pathway activation were distributed as highly reproducible environments in discrete locations throughout these tumours, which we deep-profiled using laser-capture mass spectrometry. We show that the connections between tumour phenotypes, vascularization, immune response, and stromal biophysical state are reinforced by genomic aberrations, altered by treatment, and associated with patient outcome. Predictive machine-learning models showed that spatial single cell data outperformed genomic or clinical features but integrated multi-omics models provide the best prediction of patient survival with compressed models requiring only 10 non-redundant robust molecular measures associated with the phenotypic spectrum of PDAC. Together, these findings define a phenotypic and molecular framework of PDAC that captures tumour-microenvironment co-dependencies and offers a refined basis for patient stratification and therapeutic targeting.