Purpose: Despite significant progress in understanding the pathogenesis of type 2 diabetes (T2D) , it remains difficult to manage, hence, new therapeutic options are required. We previously observed that elevated skeletal muscle succinyl CoA:3-ketoacid CoA transferase (SCOT) activity, the rate-limiting enzyme of ketone (KB) oxidation, contributes to obesity-induced hyperglycemia. Moreover, we identified that the antipsychotic agent, pimozide, is a SCOT inhibitor with glucose-lowering actions. In silico molecular modeling determined that a wide range of DPBPs can theoretically inhibit SCOT activity, therefore, we determined whether the DPBP drug class could be repurposed for the treatment of T2D.

Methods: 8-week-old male wild-type and muscle-specific/brain-specific SCOT knockout (SCOTMuscleKO, SCOTBrainKO) mice were subjected to experimental obesity via consumption of a high fat, high sugar diet for 12-weeks. Lean control mice received a low fat, low sugar diet. At 8-weeks, lean and obese mice were treated with DPBPs (penfluridol, fluspirilene, pimozide (10mg/kg)) once every 2 days via oral gavage for 14-days, following which circulating KB levels and glucose homeostasis were assessed. To rule out a contribution of the canonical actions of DPBPs as dopamine 2 (D2) receptor antagonists to DPBP-mediated glucose-lowering, obese mice were treated with the structurally unrelated D2 receptor antagonist, lurasidone (10 mg/kg) .

Results: All tested DPBPs improved glucose homeostasis in obese mice through a mechanism dependent on the inhibition of both brain and muscle SCOT activity. Treatment with lurasidone failed to improve glycemia in obese mice, thus consistent with a SCOT-dependent mechanism of action.

Conclusions: Our findings suggest all DPBPs have glucose-lowering actions and therefore may have clinical utility in being repurposed for the treatment of T2D.


S. Tabatabaei dakhili: None. C. A. Velazquez: None. P. A. Crawford: Advisory Panel; Abbott Diabetes, Johnson & Johnson Global Services. M. Glover: None. R. Al batran: None. J. R. Ussher: None. R. Abou farraj: None. A. A. Greenwell: None. C. T. Saed: None. K. Yang: None. K. Gopal: None. J. S. F. Chan: None. C. Lee: None. F. Eaton: None.


Canadian Institutes of HealthResearch

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.