Inhibition of 12/15-Lipoxygenase Protects Against β-Cell Oxidative Stress and Glycemic Deterioration in Mouse Models of Type 1 Diabetes

Abstract

Islet β-cell dysfunction and aggressive macrophage activity are early features in the pathogenesis of type 1 diabetes (T1D). 12/15-Lipoxygenase (12/15-LOX) is induced in β-cells and macrophages during T1D and produces proinflammatory lipids and lipid peroxides that exacerbate β-cell dysfunction and macrophage activity. Inhibition of 12/15-LOX provides a potential therapeutic approach to prevent glycemic deterioration in T1D. Two inhibitors recently identified by our groups through screening efforts, ML127 and ML351, have been shown to selectively target 12/15-LOX with high potency. Only ML351 exhibited no apparent toxicity across a range of concentrations in mouse islets, and molecular modeling has suggested reduced promiscuity of ML351 compared with ML127. In mouse islets, incubation with ML351 improved glucose-stimulated insulin secretion in the presence of proinflammatory cytokines and triggered gene expression pathways responsive to oxidative stress and cell death. Consistent with a role for 12/15-LOX in promoting oxidative stress, its chemical inhibition reduced production of reactive oxygen species in both mouse and human islets in vitro. In a streptozotocin-induced model of T1D in mice, ML351 prevented the development of diabetes, with coincident enhancement of nuclear Nrf2 in islet cells, reduced β-cell oxidative stress, and preservation of β-cell mass. In the nonobese diabetic mouse model of T1D, administration of ML351 during the prediabetic phase prevented dysglycemia, reduced β-cell oxidative stress, and increased the proportion of anti-inflammatory macrophages in insulitis. The data provide the first evidence to date that small molecules that target 12/15-LOX can prevent progression of β-cell dysfunction and glycemic deterioration in models of T1D.

CANDOCK: Chemical atomic network based hierarchical flexible docking algorithm using generalized statistical potentials

“…Docking methods are evaluated by predicting the correct pose/binding mode (evaluated using RMSD or TMScore of the coordinates of the atoms) or by measuring predicted binding affinities 4,8,11,12,16 . Application to protein targets involved in disease holds the promise of discovering new therapeutics using traditional single target approaches or by virtually measuring the interactions of a compound with the proteins from multi-organism proteome [17][18][19][20][21][22] . The resulting chemo-proteome interactions can be interrogated to study polypharmacology 19 and investigate the effect drugs and agents have on protein classes in a disease-specific context 19,22 .…”

“…The resulting chemo-proteome interactions can be interrogated to study polypharmacology 19 and investigate the effect drugs and agents have on protein classes in a disease-specific context 19,22 . In previous works, we have used the algorithm presented herein to combat Ebola 20 , determine the toxicity of potential diabetes therapeutics 21 , and rank the affinity of kinase inhibitors for the treatment of Acute Myeloid Leukemia 23 .…”

Hepatocyte ALOXE3 is induced during adaptive fasting and enhances insulin sensitivity by activating hepatic PPARγ

“…It should be noted that genetic disruption of both 12-LOX and 15-LOX in multiple diabetic models largely recapitulates the Aloxe3 -mediated enhancement of hepatic insulin sensitivity and reduced hepatic steatosis ( 15 – 17 ). Therefore, it is plausible that — in addition to (or perhaps in lieu of) generating the PPARγ ligand 12-KETE — eLOX3 either depletes 12-LOX products 12-HpETE and 12-HETE ( Figure 2 ) to the host’s benefit, or 12-LOX and 15-LOX deletion shunts arachidonic acid down the eLOX3 enzymatic pathway to activate PPARγ.…”

ALOXE3 is a hepatic fasting-responsive lipoxygenase that enhances insulin sensitivity via hepatic PPARγ

“…This model is also supported by the lack of effect of GW9662 also on ALOXE3-induced thermogenesis. In addition, it should be recognized that genetic disruption of both 12-LOX and 15-LOX in multiple diabetic models largely recapitulates the ALOXE3-mediated enhancement of hepatic insulin sensitivity and reduced hepatic steatosis (15)(16)(17). Therefore, it is quite feasible that -in addition to generating the PPARg ligand 12-KETE -either ALOXE3 activity also depletes 12-LOX products 12-HpETE and 12-HETE ( Fig.…”

“…In humans, a recent large cohort adults with type 2 diabetes demonstrated a potentially protective role for 5-lipoxygenases ALOX5 and ALOX5AP against diabetes mellitus (14). Conversely, ALOX12/15 inhibition in rodent models inhibited oxidative stress, b-cell deterioration, hepatic steatosis and systemic inflammation (15)(16)(17)(18). Together, these data suggest that intracellular lipid intermediary metabolism drives both tissue-level and whole-organism metabolic homeostasis.…”