Discovery of Potent Inhibitors of Schistosoma mansoni NAD⁺ Catabolizing Enzyme

Abstract

The blood fluke Schistosoma mansoni is the causative agent of the intestinal form of schistosomiasis (or bilharzia). Emergence of Schistosoma mansoni with reduced sensitivity to praziquantel, the drug currently used to treat this neglected disease, has underlined the need for development of new strategies to control schistosomiasis. Our ability to screen drug libraries for antischistosomal compounds has been hampered by the lack of validated S. mansoni targets. In the present work, we describe a virtual screening approach to identify inhibitors of S. mansoni NAD(+) catabolizing enzyme (SmNACE), a receptor enzyme suspected to be involved in immune evasion by the parasite at the adult stage. Docking of commercial libraries into a homology model of the enzyme has led to the discovery of two in vitro micromolar inhibitors. Further structure-activity relationship studies have allowed a 3-log gain in potency, accompanied by a largely enhanced selectivity for the parasitic enzyme over the human homologue CD38.

Inhibition of neuronal FLT3 receptor tyrosine kinase alleviates peripheral neuropathic pain in mice

“…The following primary antibodies were used: anti-TUJ1 (Sigma T9026 or T2220, mouse or rabbit 1:1000), anti-ATF3 (Santa Cruz sc-188, rabbit 1:500), anti-NPY (Cell Signaling 11976S, rabbit 1:500), anti-GFAP (Dako Z0334, rabbit 1:500 in spinal cord or 1:1000 in DRGs), anti-IBA1 (Wako 019-19741, rabbit 1:500), anti-CSF1 (R&D System AF416, goat 1:500), anti-CD45 (Millipore 05-1416, rat 1:100), anti-CD11b (DSHB M1/70.15.11.5.2, rat 1:100), anti-CD3 (BD Pharmagen 555273, rat 1:500), anti-CD68 (Serotec MCA1957GA, rat 1:100), anti-FLT3 ligand (Bioss 5905R, rabbit 1:100 or Cell Signaling Technology, clone 8F2 3462, rabbit 1:200), anti-GFP (Invitrogen A6455, rabbit 1:2000 orAbcam Ab13970, chicken 1:2000), anti-S100β (Sigma S2532, mouse 1:1000), anti-NF200 (Sigma N4142, rabbit 1:1000), anti-cRet (R&D System AF482, goat 1:20 unmasking citrate buffer, see refs. 26 , 65 , 66 ), anti-TrkC (R&D System AF1404, goat 1:1000), anti-TrkB R&D System AF1494 (goat 1:1000), anti-TrkA (Millipore 06574, rabbit 1:500), anti-TRPV1 (Sigma V2764, rabbit 1:1000). To identify IB4-binding cells, biotynylated IB4 (Sigma 2140, 1:100), anti-NeuN (Millipore ABN90, guinea pig 1:2000) and Extravidin-conjugated FITC (Sigma E2761, 1:400) were used in place of primary and secondary antibodies.…”

“…An in-house developed Bioinfo database 66 of 2.9 million commercially available drug-like compounds (v.2011 release) was first filtered in Pipeline Pilot v.8.5 (Accelrys) to retrieve molecules with the following properties: h-bond donor count ≥1, h-bond acceptor count ≥4, number of rotatable bonds ≤10, number of aromatic rings ≥1, polar surface area ≤90Å 2 and predicted aqueous solubility ≥50 μM. The resulting 253,193 compounds were then converted into three-dimensional coordinates using Corina v.3.1 (Molecular Networks GmbH, Erlangen, Germany) to yield a total of 343,847 unique isomers.…”

Modern approaches to accelerate discovery of new antischistosomal drugs

“…Because of their obvious advantages, VS approaches are widely employed in pharmaceutical industry and academic organizations. Nevertheless, in anti-schistosomal research, the application of VS approaches is limited by a small number of recent studies [46–50]. The main VS approaches that can be implemented in a hit identification pipeline and examples of successful applications of VS workflows leading to the identification of new anti-schistosomal hits are discussed in next sections.…”

“…In another study, Jacques and colleagues [50] describe a VS approach to identify inhibitors of S. mansoni NAD+ catabolizing enzyme (NACE), a target suspected to be involved in immune evasion by the parasite at the adult stage. An initial filtering biased of the chemical library toward compounds was performed to select small molecular weight compounds, in agreement with the small size of the binding site of NACE.…”

Manniindole, an indole derivative from the roots of Anonidium mannii and combined antischistosomal and enzymatic activities

“…SmNACE is an ecto-enzyme recently discovered which has a favorable topology because it is one of the rare identified and characterized target on the tegument of adult schistosomes responsible for serious clinic troubles. In fact, SmNACE is extremely interesting due to its accessibility of drugs and thus a potential target for conception of future therapeutic agents (Goodrich et al 2005;Kuhn et al 2010;Jacques et al 2015).…”