Submitted on October 23, 2007
Revised on March 14, 2008
Accepted on April 15, 2008
Wolman disease/cholesteryl ester storage disease: Efficacy of plant-produced human lysosomal acid lipase in mice
Hong Du, Terri L. Cameron, Stephen J. Garger, Gregory P. Pogue, Lee A. Hamm, Earl White, Kathleen M. Hanley, and Gregory A. Grabowski
Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
Corresponding Author: greg.grabowski{at}cchmc.org
Lysosomal acid lipase (LAL) is an essential enzyme that hydrolyzes triglycerides (TGs) and cholesteryl esters (CEs) in lysosomes. Genetic LAL mutations lead to Wolman disease (WD) and cholesteryl ester storage disease (CESD). A LAL null (lal-/-) mouse model resembles human WD/CESD with storage of CEs and TGs in multiple organs. Human LAL was expressed in Nicotiana benthamiana using the GENEWARE® expression system (G-hLAL). Purified G hLAL showed mannose receptor-dependent uptake into macrophage cell lines (J774E). Intraperitoneal injection of G-hLAL produced peak activities in plasma at 60 min, and in the liver and spleen at 240 min. The t1/2 values were: ~90 min (plasma), ~14 hrs (liver), and ~32 hrs (spleen) with return to baseline by ~150 hrs in liver and ~200 hrs in spleen. Ten injections of G-hLAL (every 3 days) into lal-/- mice produced normalization of hepatic color, decreases in hepatic cholesterol and TG contents, and diminished foamy macrophages in liver, spleen and intestinal villi. All injected lal-/- mice developed anti-hLAL protein antibodies, but suffered no adverse events. These studies demonstrate the feasibility of using plant-expressed, recombinant hLAL for the enzyme therapy of human WD/CESD with general implications for other lysosomal storage diseases.