BLT-1, a thiosemicarbazone copper chelator, is a selective scavenger receptor B, type 1 (SR-BI) inhibitor. BLT-1 inhibits the transfer of lipids between high-density lipoproteins (HDL) and cells mediated by SR-BI. BLT-1 is a potent HCV entry inhibitor. BLT-1 has pro-inflammatory functions through neutrophil recruitment[1][2][3][4].

BLT-1 has IC50s of 60 and 110 nM for cellular DiI-HDL and [3H]CE-HDL uptake in ldlA[mSR-BI] cells[1]. BLT-1 has an IC50 of 0.96 μM for the HCV entry in Huh 7.5.1 cells[4]. BLT-1 (50 μM; 3 hours) does not induce general defects in clathrin-dependent and -independent intracellular membrane trafficking in HeLa, BSC-1 cells[1]. BLT-1 can inhibit SR-BI-dependent selective uptake of [3H]CE from [3H]CE-HDL by mSR-BI-t1-containing liposomes in cells (IC50=0.057 µM) and liposomes (IC50=0.098 µM) [2].

[1]. Nieland TJ, et al. Discovery of chemical inhibitors of the selective transfer of lipids mediated by the HDL receptorSR-BI. Proc Natl Acad Sci U S A. 2002 Nov 26;99(24):15422-7. [2]. Nieland TJ, et al. Identification of the molecular target of small molecule inhibitors of HDL receptor SR-BI activity. Biochemistry. 2008 Jan 8;47(1):460-72. [3]. RaldÚa D, et al. BLT-1, a specific inhibitor of the HDL receptor SR-BI, induces a copper-dependent phenotype during zebrafish development. Toxicol Lett. 2007 Dec 10;175(1-3):1-7. Epub 2007 Aug 22. [4]. Hirofumi Ohashi, et al. Reply to Padmanabhan and Dixit: Hepatitis C virus entry inhibitors for optimally boosting direct-acting antiviral-based treatments. Proc Natl Acad Sci U S A. 2017 Jun 6;114(23):E4527-E4529.