Halofuginone is a coccidiostat used in veterinary medicine. Collgard Biopharmaceuticals is developing halofuginone for the treatment of scleroderma. Halofuginone inhibits the development of T helper 17 cells, immune cells that play an important role in autoimmune disease, but it does not affect other kinds of T cells which involved in normal immune function. Halofuginone therefore has potential for the treatment of autoimmune disorders. Halofuginone is also an inhibitor of collagen type I gene expression and as a consequence it may inhibit tumor cell growth. Halofuginone exerts its effects by acting as a high affinity inhibitor of the enzyme Glutamyl-Prolyl tRNA synthetase. Inhibition of prolyl tRNA charging leads to the accumulation of uncharged prolyl tRNAs, which serve as a signal to initiate the amino acid starvation response, which in turn exerts anti-inflammatory and anti-fibrotic effects.
-O115.gif)