Investigating the Molecular Mechanism of DS16570511 in Endothelial Fatty Acid Uptake

Endothelial cells regulate the transport of fatty acids from the bloodstream into underlying metabolic tissues. Dysregulation of fatty acid transport across endothelial cells is recognized as a significant contributor to various health conditions, including insulin resistance, atherosclerosis, and obesity. Recent studies have identified specific monocarboxylate molecules, such as lactate and 3-hydroxyisobutyrate, as stimulators of endothelial fatty acid uptake. DS16570511, a mitochondrial calcium uniporter (MCU) inhibitor, has garnered attention due to its unique role in fatty acid uptake. Preliminary work has revealed that DS16570511 selectively decreases monocarboxylate-stimulated fatty acid uptake, while having minimal effect on basal fatty acid uptake. This study aims to elucidate the molecular mechanism by which DS16570511 decreases monocarboxylate-stimulated fatty acid uptake in endothelial cells. We hypothesized that DS16570511's effect on stimulated fatty acid uptake is mediated through its known inhibition of MCU. To evaluate the role of the MCU in endothelial fatty acid uptake, we conducted orthogonal experiments using both pharmacologic and genetic approaches. First, we compared DS16570511 to two other MCU inhibitors: Mitoxantrone and Ru265. We cultured endothelial cells, treated them with MCU inhibitors in basal and stimulated conditions, and quantified fatty acid uptake by measuring the uptake of BODIPY-C12, a fluorescent fatty acid analog. In contrast to DS16570511, Mitoxantrone and Ru265 did not significantly decrease stimulated fatty acid uptake. In a separate experiment, we knocked down MCU expression using siRNA and treated cells with DS16570511 in basal and stimulated conditions. Strikingly, we observed that DS16570511 decreased stimulated fatty acid uptake in MCU-deficient cells to a similar extent as control cells. These orthogonal findings indicate that DS16570511 decreases stimulated fatty acid uptake through an MCU-independent mechanism. Future studies will focus on identifying the targets associated with DS16570511's selective inhibitory activity. Identifying these targets may reveal novel mechanisms regulating endothelial fatty acid uptake and provide new therapeutic strategies for treating metabolic disorders.