In vivo and ex vivo evaluation of L-type calcium channel blockers on acid beta-glucosidase in Gaucher disease mouse models

• Published in: PloS one Vol. 4; no. 10; p. e7320
• Main Authors: Sun, Ying, Liou, Benjamin, Quinn, Brian, Ran, Huimin, Xu, You-Hai, Grabowski, Gregory A
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 07.10.2009; Public Library of Science (PLoS)
• Subjects: Acids; Animal models; Animals; Brain; Calcium; Calcium Channel Blockers - pharmacology; Calcium channels; Calcium channels (L-type); Calcium Channels, L-Type - chemistry; Cardiomyopathy; Cell Biology; Children & youth; Diltiazem; Diltiazem - pharmacology; Disease Models, Animal; Drinking water; Endoplasmic reticulum; Enzymes; Fibroblasts; Fibroblasts - drug effects; Gaucher Disease - drug therapy; Gaucher Disease - genetics; Gaucher's disease; Genetics and Genomics/Disease Models; Genetics and Genomics/Genetics of Disease; Glucosidase; Glucosylceramidase - metabolism; Heart failure; Homozygote; Homozygotes; Hospitals; Liver; Lysosomes; Medicine; Mice; Mice, Transgenic; Models, Biological; Mutagenesis; Mutation; Pediatrics; Protein folding; Protein transport; Skin - drug effects; Skin tests; Substrates; Verapamil; Verapamil - pharmacology; United States > US; Ohio
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0007320

Gaucher disease is a lysosomal storage disease caused by mutations in acid beta-glucosidase (GCase) leading to defective hydrolysis and accumulation of its substrates. Two L-type calcium channel (LTCC) blockers-verapamil and diltiazem-have been reported to modulate endoplasmic reticulum (ER) folding, trafficking, and activity of GCase in human Gaucher disease fibroblasts. Similarly, these LTCC blockers were tested with cultured skin fibroblasts from homozygous point-mutated GCase mice (V394L, D409H, D409V, and N370S) with the effect of enhancing of GCase activity. Correspondingly, diltiazem increased GCase protein and facilitated GCase trafficking to the lysosomes of these cells. The in vivo effects of diltiazem on GCase were evaluated in mice homozygous wild-type (WT), V394L and D409H. In D409H homozygotes diltiazem (10 mg/kg/d via drinking water or 50-200 mg/kg/d intraperitoneally) had minor effects on increasing GCase activity in brain and liver (1.2-fold). Diltiazem treatment (10 mg/kg/d) had essentially no effect on WT and V394L GCase protein or activity levels (<1.2-fold) in liver. These results show that LTCC blockers had the ex vivo effects of increasing GCase activity and protein in the mouse fibroblasts, but these effects did not translate into similar changes in vivo even at very high drug doses.