SAT071 Inhibition Of 12 Lipoxygenase In A Humanized Mouse Model Of Type 1 Diabetes Delays Progression Of Hyperglycemia

Abstract

Abstract Disclosure: T. Nargis: None. A. Chakraborty: None. K. Figatner: None. D. Maloney: None. M. Boxer: None. S.A. Tersey: None. R.G. Mirmira: None. Type 1 diabetes (T1D) is an autoimmune disorder characterized by islet inflammation (insulitis). We have recently shown that a key mediator of inflammatory signaling in the islet beta cell is the enzyme 12-lipoxygenase (12-LOX), which generates proinflammatory eicosanoids that augment dysfunctional insulin secretion and beta-cell visibility to the immune system. Whereas inhibition of 12-LOX offers an opportunity to modify T1D progression by altering how the beta cell responds to insulitis, a barrier to testing inhibitors in preclinical models is the specificity of next generation inhibitors toward the human enzyme. To generate a preclinical platform for the study of human-specific 12-LOX inhibitors, we developed a mouse model in which the mouse-equivalent Alox15 coding region was replaced with the human ALOX12 gene, while retaining the mouse upstream control region. These mice (hALOX12) were developed on both the C57BL/6J and NOD genetic backgrounds, then subjected to treatment with the human 12-LOX inhibitor VLX-1005 to evaluate diabetes progression. C57BL/6J-wildtype and C57BL/6J-hALOX12 mice were confirmed to express exclusively mouse Alox15 and human ALOX12, respectively, using RNA isolated from islets. To test susceptibility to toxin-induced diabetes, C57BL/6J-wildtype and C57BL/6J-hALOX12 were subjected to multiple low-dose streptozotocin (STZ) to induce diabetes. Both wildtype and humanized mice exhibited gradual and equivalent hyperglycemia (within 25 days) following STZ injection. Following intraperitoneal VLX-1005 therapy (30 mg/kg), whereas C57BL/6J-wildtype mice developed diabetes (with a delay of 10 days) following STZ, C57BL/6J-hALOX12 mice showed complete protection against STZ-induced diabetes and exhibited significantly better glucose tolerance compared to vehicle- or VLX-1005-injected wildtype controls and vehicle-injected C57BL/6J-hALOX12 mice. Next, hALOX12 mice were backcrossed onto the NOD.ShiltJ background model of autoimmune T1D. NOD-hALOX12 mice received either vehicle or VLX-1005 (30 mg/kg) orally during the prediabetic phase (6-10 weeks of age) and were followed for diabetes incidence. Mice receiving VLX-1005 showed a significant delay with only 30% of female and 7% of male mice developing diabetes over 25 weeks of age. Pancreatic sections from the mice treated with VLX-1005 showed reduced insulitis and increased beta cell mass compared to vehicle controls. In summary, the hALOX12 mouse model serves as a preclinical translational platform to interrogate effects of next generation 12-LOX inhibitors and demonstrates the potential of VLX-1005 to modify T1D disease progression. Presentation: Saturday, June 17, 2023