Halofuginone HBr

Potent and selective prolyl-tRNA synthetase (PRS) inhibitor (Ki=18.3 nM) derived from febrifugine.1 Also attenuates TGF-β signaling, including reversibly reducing Smad3 protein levels and inhibiting fibroblast differentiation.2 Blocks fibrosis, angiogenesis, and tumor progression.2,3 Inhibition of PRS results in amino acid starvation which activates the integrated stress response (ISR) and mTOR signaling4 and thus preventing differentiation of TH17 cells, suppressing the autoimmune response5. Reduces TMPRSS2 protein levels via enhanced ubiquitination and proteasomal degradation, limiting SARS-CoV-2 cellular entry.6