Results from the recently completed TINSAL-T2D trials showed that salicylate (SA), the world's oldest anti- inflammatory drug, also lowers blood glucose levels as effectively as many approved drugs. And metformin, the most used drug worldwide for type 2 diabetes (T2D), has anti-inflammatory actions in addition to lowering blood glucose. These counterpoints provide major new clues to drug mechanisms and more generally to molecular/cellular links between metabolism and immunity. While metformin's molecular binding target(s) and metabolic mechanisms are appropriately debated, it can activate AMPK. SA also activates AMPK, and other AMPK activators like AICAR are also anti-inflammatory. In fact, AMPK activation has been shown to inhibit NF-?B in certain settings. This proposal identifies molecular links between AMPK and NF?B that account for the intrinsic anti-inflammatory properties of AMPK agonists. These findings have clinical potential. We focus here on treatments for T2D that may decrease risk for cardiovascular disease (CVD), but findings are also relevant to indications ranging from cancer to neuroprotection. T2D promotes CVD, which accounts for >85% of deaths in patients with T2D. There is thus a tremendous unmet need to reduce CV risk in patients with T2D. Met has been suggested to be cardioprotective and we have found that SA lessens plaque in predisposed Ldlr null mice, but neither drug has been studied in a prospective CV outcomes trial. Preliminary results show for the first time that SA-mediated AMPK activation and NF?B inhibition, two seemingly independent events, are inextricably linked through AMPK inhibition of mTORC1. SA directly binds AMPK to enhance its phosphorylation. Preliminary data show that SA- or AICAR-activated AMPK activates tumor suppressor TSC1/2, which enhances its GAP activity to inhibit Rheb, the small GTPase needed for mTOR activation. We further show this inhibits the nutrient sensor, mTORC1, which decreases TRAF6 and p62/SQSTM1 dependent ubiquitination of IKK? to destabilize the IKK signalosome and inhibit canonical NF?B signaling. AMPK activation and mTOR inhibition also increase expression and activity of the transcription factor KLF2, which also inhibits NF?B. Proposed experiments test these hypotheses and translate findings from cells and atherosclerosis-prone mice to samples from SA-treated subjects in the TINSAL-CVD trial.
We found that metformin, the world's most used drug for diabetes, and salicylate, the world's oldest anti- inflammatory drug, have very similar mechanisms of action for reducing inflammation. Because inflammation promotes cardiovascular disease, the leading cause of death in patients with diabetes, we are mapping the molecular pathways for the actions of these drugs and assessing potential roles of the drugs and the pathway for reducing cardiovascular risk in patients with diabetes.
| Goldfine, Allison B; Shoelson, Steven E (2017) Therapeutic approaches targeting inflammation for diabetes and associated cardiovascular risk. J Clin Invest 127:83-93 |
