Selective Inhibitors of Human Neuraminidase 1 (NEU1)

Abstract

Inhibitors of human neuraminidase enzymes (NEU) are recognized as important tools for the study of the biological functions of NEU and will be potent tools for elucidating the role of these enzymes in regulating the repertoire of cellular glycans. Here we report the discovery of selective inhibitors of the human neuraminidase 1 (NEU1) and neuraminidase 2 (NEU2) enzymes with exceptional potency. A library of modified 2-deoxy-2,3-didehydro-N-acetylneuraminic acid (DANA) analogues, with variability in the C5- or C9-position, were synthesized and evaluated against four human neuraminidase isoenyzmes (NEU1–4). Hydrophobic groups with an amide linker at the C5 and C9 positions were well accommodated by NEU1, and a hexanamido group was found to give the best potency at both positions. While the C5-hexanamido-C9-hexanamido-DANA analogue did not show synergistic improvements for combined modification, an extended alkylamide at an individual position combined with a smaller group at the second gave increased potency. The best NEU1 inhibitor identified was a C5-hexanamido-C9-acetamido-DANA that had a K i of 53 ± 5 nM and 340-fold selectivity over other isoenzymes. Additionally, we demonstrated that C5-modifications combined with a C4-guandino group provided the most potent NEU2 inhibitor reported, with a K i of 1.3 ± 0.2 μM and 7-fold selectivity over other NEU isoenzymes.

Polyvalent Transition‐State Analogues of Sialyl Substrates Strongly Inhibit Bacterial Sialidases**

“…Polymer 18 was prepared by ring-opening metathesis polymerization (ROMP) of norbornenyl azlactone (NBAzl) using ruthenium-based Grubbs' third generation catalyst leading to a poly(NBAzl) 115 of M n,NMR = 23700 g.mol -1 , DP n,NMR = 115, M n,SEC THF = 25300 g.mol -1 , Ð = 1.12. [40,41] The azlactone moieties of polymers 16 and 18 were easily reacted with one equivalent of amine 12 to form the corresponding azido-polymers 17 and 19, respectively, as demonstrated by 1 ) values (>20 ppm) observed using 13 C NMR. [42] Scheme 3.…”

“…SA are widely present in animal species, and unbalanced human SA activity plays a crucial role in diabetes, inflammation, cancers and cardiovascular and lysosomal storage diseases. [1] SA are also common virulent factors of pathogenic microorganisms, enabling them to develop biofilms, to feed on host sialic acid, or to infect cells by unmasking binding ligands. SA are therefore particularly relevant targets for the development of anti-infective therapies against viruses, bacteria, fungi and parasites.…”

“…DANA modifications with adequate pharmacophores at the C-5 or C-9 positions were shown to improve affinity and selectivity for specific hNEU isoenzymes. [1,[4][5][6][7][8] The group of Chen developed triazolelinked peptide in C-9 position of DANA with micromolar and selective inhibition of V. cholerae SA. [9] Virulent factors interfering with host sialoglycans may also be efficiently targeted or inhibited with synthetic glycoclusters bearing several copies of the sialic acid epitope.…”

Human neuraminidases have reduced activity towards modified sialic acids on glycoproteins

“…Previous results with an artificial substrate based on 4MU-NANA (4) found a 2-fold preference for Neu5Ac over Neu5,9Ac2, and a selective NEU1 inhibitor developed by our group contains a C9 acetamido group, suggesting that NEU1 may be more tolerant of an acetate at C9. 46 It is important to note that the ratiosof Neu5,9Ac2 to Neu5Ac released by hNEU were all defined by the limit of detection and thus indicate a lower limit, rather than absolute, substrate preference. As a result the discrimination against Neu5,9Ac2 may be even greater than calculated here.…”

The sialidase inhibitor 2,3-dehydro-2-deoxy-N-acetylneuraminic acid is a glucose-dependent potentiator of insulin secretion

“…Activation of the insulin receptor by insulin was attenuated by inhibition of endogenous Neu1 by pretreatment with 1 mM DANA. Although DANA inhibits all mammalian sialidase isozymes 35,36 , sialidase isozyme-selective inhibitors have recently been developed for Neu1, Neu2, Neu3 and Neu4 [36][37][38][39][40] . Sialidase isozyme-selective inhibitors that do not inhibit Neu1 activity may thus be suitable for the treatment of diabetes mellitus.…”