(5aR)-5a-C-Pentyl-4-epi-isofagomine: A powerful inhibitor of lysosomal β-galactosidase and a remarkable chaperone for mutations associated with GM1-gangliosidosis and Morquio disease type B.
Eur J Med Chem 2016;
126:160-170. [PMID:
27750150 DOI:
10.1016/j.ejmech.2016.09.095]
[Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/26/2016] [Accepted: 09/29/2016] [Indexed: 12/14/2022]
Abstract
This report is about the identification, synthesis and initial biological characterization of derivatives of 4-epi-isofagomine as pharmacological chaperones (PC) for human lysosomal β-galactosidase. The two epimers of 4-epi-isofagomine carrying a pentyl group at C-5a, namely (5aR)- and (5aS)-5a-C-pentyl-4-epi-isofagomine, were prepared by an innovative procedure involving in the key step the addition of nitrohexane to a keto-pentopyranoside. Both epimers were evaluated as inhibitors of the human β-galactosidase: the (5aR)-stereoisomer (compound 1) was found to be a very potent inhibitor of the enzyme (IC50 = 8 nM, 30× more potent than 4-epi-isofagomine at pH 7.3) with a high selectivity for this glycosidase whereas the (5aS) epimer was a much weaker inhibitor. In addition, compound 1 showed a remarkable activity as a PC. It significantly enhanced the residual activity of mutant β-galactosidase in 15 patient cell lines out of 23, with enhancement factors greater than 3.5 in 10 cell lines and activity restoration up to 91% of normal. Altogether, these results indicated that (5aR)-5a-C-pentyl-4-epi-isofagomine constitutes a promising PC-based drug candidate for the treatment of GM1-gangliosidosis and Morquio disease type B.
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