Novel Chemical Scaffolds to Inhibit the Neutral Amino Acid Transporter B0AT1 (SLC6A19), a Potential Target to Treat Metabolic Diseases

Abstract

Lack of B 0 AT1 (SLC6A19) partially protects mice against the onset of non-alcoholic steatohepatitis (NASH). To achieve a similar outcome through pharmacological treatment, we improved previously identified inhibitors of B 0 AT1 by medicinal chemistry and identified second generation inhibitors by high through-put screening. Modified diarylmethine compounds inhibited B 0 AT1 with IC 50 values ranging from 8-90 mM. A second generation of inhibitors was derived from high-throughput screening and showed higher affinity (IC 50 of 1-15 mM) and strong selectivity against amino acid transporters with similar substrate specificity, such as ASCT2 (SLC1A5) and LAT1 (SLC7A5). All compounds were unrelated to B 0 AT1 substrates, but were likely to bind in the vicinity of the substrate binding site.

A Solid Supported Membrane-Based Technology for Electrophysical Screening of B0AT1-Modulating Compounds

“…Recently, membrane potential-sensing fluorescent assays (FLIPR) were developed for the identification of novel inhibitors of B 0 AT1. 32,35 Benztropine was one of the substances identified and further characterized by the FLIPR assay. 32 Using the SSM-based assay, the sensitivity of B 0 AT1 against benztropine could not be reproduced, even at high compound concentrations (up to 130 µM) ( Fig.…”

“…The recently published inhibitors of the second generation, which exhibit a potency of around 1–15 µM, could be more promising tool compounds compared with nimesulide and benztropine. 35…”

Transporters at the Interface between Cytosolic and Mitochondrial Amino Acid Metabolism

“…Other transport systems can facilitate BCAA uptake, including the Na+-dependent SLC6A19/B0AT1, which may contribute to differing sensitivity in response to LAT1-deletion [ 173 , 174 ]. Inhibitors targeting SLC6A19/B0AT1 have been developed using in silico and high-throughput screening approaches [ 175 , 176 ].…”

Branched chain amino acids—friend or foe in the control of energy substrate turnover and insulin sensitivity?

“…Recently, inhibitors of SLC6a19/B 0 AT1 were shown to block amino acid uptake in mouse intestine and kidneys (Q. Cheng et al 2017;Yadav et al 2020;Danthi et al 2019). The metabolic outcomes of such intervention may resemble the effects observed in SLC6a19/B 0 AT1-depleted mice, such as greater GLP-1 and FGF21 release, reduced mTOR signaling in muscle, adipose tissue and liver, improved glycaemic control, reduced adiposity and hepatic glucose output, low levels of triacylglycerol and cholesterol, decreased steatosis in the liver, and resistance to diet-induced obesity (Yadav et al 2020;Jiang et al 2015).…”