Fatty acid transport protein-2 inhibitor Grassofermata/CB5 protects cells against lipid accumulation and toxicity

Abstract

The inhibition of the fatty acid uptake into non-adipose tissues provides an attractive target for prevention of lipotoxicity leading to obesity-associated non-alcoholic fatty liver disease and type 2 diabetes. Fatty acid transport proteins (FATPs) are bifunctional proteins involved in the uptake and activation of fatty acids by esterification with coenzyme A. Here we characterize Grassofermata/CB5, previously identified as a fatty acid uptake inhibitor directed against HsFATP2. The compound was effective in inhibiting the uptake of fatty acids in the low micro-molar range (IC50 8–11μM) and prevented palmitate-mediated lipid accumulation and cell death in cell lines that are models for intestines, liver, muscle and pancreas. In adipocytes, uptake inhibition was less effective (IC50 58μM). Inhibition was specific for long chain fatty acids and was ineffective toward medium chain fatty acids, which are transported by diffusion. Kinetic analysis of Grassofermata-dependent FA transport inhibition verified a non-competitive mechanism. By comparison with Grassofermata, several atypical antipsychotic drugs previously implicated as inhibitors of FA uptake were ineffectual. In mice Grassofermata decreased absorption of 13C-oleate demonstrating its potential as a therapeutic agent.

Fatty acid transport proteins: targeting FATP2 as a gatekeeper involved in the transport of exogenous fatty acids

“…As predicted, treatment of cells with this compound does not alter medium chain fatty acid transport. Consistent with in vitro studies, Grassofermata, like Lipofermata when delivered orally, prevents intestinal absorption of 13 C labeled oleate 117 . Pharmacokinetic data show this inhibitor is detectible in the blood within 30 minutes of dosing and for up to 6 hours indicating it is absorbed as well 117 .…”

“…Like Lipofermata, Grassofermata is inhibits the transport of fluorescent fatty acid-analog C 1 -BODIPY-C 12 in various cell lines that are models for small intestine, liver, pancreatic islets, muscles and human adipocytes 102 . Inhibition by Grassofermata is specific for long and very long chain fatty acid transport and is protective effects against palmitic acid induced lipoapoptosis 39, 116, 117 . As predicted, treatment of cells with this compound does not alter medium chain fatty acid transport.…”

Deletion of fatty acid transport protein 2 (FATP2) in the mouse liver changes the metabolic landscape by increasing the expression of PPARα-regulated genes

“…2B). FATP2 is highly expressed in the small intestine and our previous results showed that control mice treated with the FATP2-specific inhibitor, Lipofermata, were compromised in their ability to absorb dietary fatty acids (13) and thus, we expected Fatp2 -/mice would result in comparable outcomes. Male mice were fasted and following the intraperitoneal injection of tyloxapol to inhibit lipoprotein lipase-dependent systemic fatty acid uptake, they were gavaged with 500 mg/kg uniformly 13 C-labeled oleate (C18:1) in flaxseed oil.…”

“…Emerging evidence suggests increased expression of FATP2 is linked to non-alcoholic fatty liver disease, renal disease and some cancers (2,(11)(12)(13). Under conditions of lipid overload, increased expression of FATP2 in the liver leads to increased fat accumulation, inflammation and organellar dysfunction (10,14,15).…”

“…Under conditions of lipid overload, increased expression of FATP2 in the liver leads to increased fat accumulation, inflammation and organellar dysfunction (10,14,15). The selective inhibition of fatty acid (FA) transport using the FATP2-specific FA transport inhibitor, Lipofermata, attenuates palmitate-induced lipotoxicity in HepG2 cells and depresses fatty acid absorption across the intestine in mice (2,13,16). In some cancers, the increased expression of FATP2 is correlated with the accumulation of triglyceride-rich lipid droplets and the promotion of metastasis, which may stem from increased FA transport (e.g., used for energy, membrane synthesis) or VLCFA activation for essential metabolic processes (e.g., membrane synthesis, synthesis of regulatory FA metabolites) (16)(17)(18).…”