Identification of novel inhibitors of the amino acid transporter B(0) AT1 (SLC6A19), a potential target to induce protein restriction and to treat type 2 diabetes

BACKGROUND AND PURPOSE The neutral amino acid transporter B(0) AT1 (SLC6A19) has recently been identified as a possible target to treat type 2 diabetes and related disorders. B(0) AT1 mediates the Na(+) -dependent uptake of all neutral amino acids. For surface expression and catalytic activity, B(0) AT1 requires coexpression of collectrin (TMEM27). In this study, we established tools to identify and evaluate novel inhibitors of B(0) AT1. EXPERIMENTAL APPROACH A CHO-based cell line was generated, stably expressing collectrin and B(0) AT1. Using this cell line, a high-throughput screening assay was developed, which uses a fluorescent dye to detect depolarisation of the cell membrane during amino acid uptake via B(0) AT1. In parallel to these functional assays, we ran a computational compound screen using AutoDock4 and a homology model of B(0) AT1 based on the high-resolution structure of the highly homologous Drosophila dopamine transporter. KEY RESULTS We characterized a series of novel inhibitors of the B(0) AT1 transporter. Benztropine was identified as a competitive inhibitor of the transporter showing an IC50 of 44 ± 9 μM. The compound was selective with regard to related transporters and blocked neutral amino acid uptake in inverted sections of mouse intestine. CONCLUSION AND IMPLICATIONS The tools established in this study can be widely used to identify new transport inhibitors. Using these tools, we were able to identify compounds that can be used to study epithelial transport, to induce protein restriction, or be developed further through medicinal chemistry.The work reported here was supported by a sponsored research contract with Sanofi (Germany)

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

Lack of B0 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 B0 AT1 by medicinal chemistry and identified second generation inhibitors by high through-put screening. Modified diarylmethine compounds inhibited B0 AT1 with IC50 values ranging from 8–90 mM. A second generation of inhibitors was derived from high-throughput screening and showed higher affinity (IC50 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 B0 AT1 substrates, but were likely to bind in the vicinity of the substrate binding siteWork in the laboratory of the authors was funded by Australian Research Council Grant: DP180101702 and National Health and Medical Research Council Grant: 1128442. The high-throughput screen was funded by a Grant from Diabetes Australia

ExScal: Elements of an Extreme Scale Wireless Sensor Network

Project ExScal (for Extreme Scale) fielded a 1000+ node wireless sensor network and a 200+ node peer-to-peer ad hoc network of 802.11 devices in a 1.3km by 300m remote area in Florida, USA during December 2004. In comparison with previous deployments, the ExScal application is relatively complex and its networks are the largest ones of either type fielded to date. In this paper, we overview the key requirements of ExScal, the corresponding design of the hardware/software platform and application, and some results of our experiments