OR34-05 12-Lipoxygenase Inhibition Improves Glucose Homeostasis and Obesity-Associated Inflammation in Human Gene Replacement Mice

Abstract Disclosure: K.B. Kaylan: None. T. Nargis: None. K. Figatner: None. J.E. Wang: None. S. Pratuangtham: None. A. Chakraborty: None. I. Casimiro: None. J.L. Nadler: None. M.B. Boxer: MBB is a Veralox Therapeutics employee. D.J. Maloney: DJM is a Veralox Therapeutics employee. R.M. Anderson: None. R.G. Mirmira: RGM received an investigator-initiated award from Veralox Therapeutics. RGM serves on the Scientific Advisory Board for Veralox Therapeutics. S.A. Tersey: SAT received an investigator-initiated award from Veralox Therapeutics. Individuals with obesity can develop peripheral insulin resistance and hyperinsulinism even without impaired glucose tolerance or type 2 diabetes (T2D). Obesity is also associated with macrophage infiltration in peripheral tissues, further contributing to insulin resistance and progression to T2D. The enzyme 12-lipoxygenase (12-LOX) catalyzes the formation of pro-inflammatory eicosanoids and is known to promote the migration of macrophages, yet its role in T2D and obesity-associated inflammation remains incompletely understood. Here, we used a human gene replacement mouse model in which endogenous mouse Alox15 is replaced by the human ALOX12 (B6.hALOX12). As a human-relevant model of obesity and T2D, we treated male B6.hALOX12 mice at 8 weeks of age with high-fat diet (HFD, 60% total calories from fat) and vehicle or VLX-1005, a potent and selective inhibitor of 12-LOX, given by oral gavage at 30 mg/kg/day for 10 weeks. B6.hALOX12 mice treated with VLX-1005 showed improved random-fed blood glucose levels and glucose tolerance testing with non-statistically significant improvements in insulin tolerance testing, glucose-stimulated insulin secretion, and homeostasis model assessment of insulin resistance values. In these mice, we additionally observed no changes in β cell mass, decreased β cell dedifferentiation, and decreased macrophage infiltration in islets and adipose tissue. Western blot analysis of adipose tissue immediately after insulin injection (3 units/kg) showed improved biochemical insulin sensitivity by phosphorylated AKT with VLX-1005 treatment. Isolation of the stromal vascular fraction from adipose tissue showed decreases in CD11b+ myeloid cells and Tnfα expression with VLX-1005 treatment. In a complementary transgenic zebrafish model in which macrophages are labelled by GFP, Tg(mpeg:eGFP)gI22, we observed decreased macrophage infiltration in pancreatic islets with VLX-1005 treatment after a HFD treatment (5% egg yolk). Last, to answer whether LOX enzyme expression has cell type-specific effects, we generated a conditional knockout of Alox15 in myeloid cells (B6.Alox15Δmyel). In B6.Alox15Δmyel mice, we observed unchanged glucose homeostasis and β cell mass, decreased β cell dedifferentiation, and decreased macrophage infiltration in both islets and adipose tissue. In summary, inhibition of 12-LOX with VLX-1005 in B6.hALOX12 mice results in improvement in glucose homeostasis and decreased macrophage infiltration in islets and adipose tissue. Our mouse model provides a platform by which to investigate the pathophysiological role of 12-LOX in other metabolic diseases, such as atherosclerosis and metabolic-dysfunction associated steatotic liver disease. These findings also suggest that 12-LOX inhibition could serve as a therapeutic strategy for obesity and T2D. Presentation: Monday, July 14, 2025