Targeting β-cell preservation in prediabetes to lower cardiovascular risk: Preclinical assessment of DLK inhibition as an innovative antidiabetic approach

Abstract 1. Introduction Cardiovascular disease remains the leading cause of death in the Western world. Metabolic syndrome (MetS), characterised by chronic low-grade inflammation, hypertension and insulin resistance or type 2 diabetes mellitus (T2DM), is a major contributor to cardiovascular risk. We have previously identified dual leucine zipper kinase (DLK, also known as MAP3K12) as a stress-activated signalling node in pancreatic β-cells. In prediabetic conditions, this triggers the phosphorylation of c-Jun N-terminal kinase (JNK) and β-cell apoptosis. These findings highlight DLK as a potential pharmacological target for protecting β-cells and modifying cardiometabolic disease. 2. Purpose This study aimed to evaluate the therapeutic potential of pharmacological DLK inhibition in preserving β-cell mass and improving glucose homeostasis under prediabetic conditions. This was achieved using isolated murine islets, transgenic mouse models, and a diabetic mouse model. 3. Methods β-DLK⁻/⁻ mice were generated by crossing DLKfl/fl mice with RIP-Cre mice. Isolated islets were analysed for apoptosis (TUNEL assay) and signalling pathways (immunoblotting). Pancreatic sections were examined to determine islet area and proliferation (Ki67). Ccl2 expression in white adipose tissue was quantified by qPCR. HbA1c, insulin and blood glucose levels were measured using the A1CNow+ system, ELISA and glucometry, respectively. The selective small-molecule DLK inhibitor GNE-3511 was used for pharmacological target validation.target validation. 4. Results Glucolipotoxic conditions induced JNK phosphorylation in isolated islets, a process that was significantly reduced by GNE-3511. Consistently, islets from β-DLK⁻/⁻ mice were protected from cytokine- and high-glucose-induced JNK activation and β-cell apoptosis. On a Western diet, β-DLK⁻/⁻ mice showed increased β-cell proliferation and a larger islet area. They were also protected from rising HbA1c and blood glucose levels, and had higher circulating insulin levels and an improved insulin/glucose ratio compared with controls, despite similar weight gain and adipose tissue inflammation. Notably, the pharmacological inhibition of DLK with GNE-3511 reduced β-cell apoptosis in islets from db/db mice, demonstrating the therapeutic efficacy of this approach in a model of established diabetes. 5. Conclusions Pharmacological inhibition of DLK preserves β-cell mass and improves metabolic control under prediabetic and diabetic conditions. These findings identify DLK as a promising drug target with translational potential for reducing the cardiovascular risk associated with diabetes.