Small molecule inhibitors of protein interaction with glycosaminoglycans (SMIGs), a novel class of bioactive agents with anti-inflammatory properties.
BACKGROUND
Small molecule inhibitors of biologically important protein-glycosaminoglycan (GAG) interactions have yet to be identified.


METHODS
Compound libraries were screened in an assay of L-selectin-IgG binding to heparin (a species of heparan sulfate [HS-GAG]). Hits were validated, IC-50s established and direct binding of hits to HS-GAGs was investigated by incubating compounds alone with heparin. Selectivity of inhibitors was assessed in 11 different protein-GAG binding assays. Anti-inflammatory activity of selected compounds was evaluated in animal models.


RESULTS
Screening identified a number of structurally-diverse planar aromatic cationic amines. Scaffolds similar to known GAG binders, chloroquine and tilorone, were also identified. Inhibitors displayed activity also against bovine kidney heparan sulfate. Direct binding of compounds to GAGs was verified by incubating compounds with heparin alone. Selectivity of inhibitors was demonstrated in a panel of 11 heparin binding proteins, including selectins, chemokines (IL-8, IP-10), Beta Amyloid and cytokines (VEGF, IL-6). A number of selected lead compounds showed dose-dependent efficacy in peritonitis, paw edema and delayed type hypersensitivity.


CONCLUSIONS
A new class of compounds, SMIGs, inhibits protein-GAG interaction by direct binding to GAGs. Although their IC-50s were in the low micro-molar range, SMIGs binding to HS-GAGs appeared to be stable in physiological conditions, indicating high avidity binding. SMIGs may interfere with major checkpoints for inflammatory and autoimmune events.


CONCLUSIONS
SMIGs are a class of structurally-diverse planar aromatic cationic amines that have an unusual mode of action - inhibiting protein-GAG interactions via direct and stable binding to GAGs. SMIGs may have therapeutic potential in inflammatory and autoimmune disorders.
Rimonyx Pharmaceuticals Ltd., Rabin Science Park, Ness-Ziona 70400, Israel; Ephraim Katzir Department of Biotechnology Engineering, ORT Braude Academic College of Engineering, Karmiel, Israel.
Nicholas
N
Harris
Faina Yurgenzon
FY
Kogan
Gabriela
G
Il'kova
Stefan
S
Juhas
Orly
O
Lahmy
Yevgeniya I
YI
Gregor
Juraj
J
Koppel
Regina
R
Zhuk
Paul
P
Gregor
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002351:Carrageenan / Q000633:toxicity; D002417:Cattle; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004487:Edema / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D057166:High-Throughput Screening Assays; D006801:Humans; D006968:Hypersensitivity, Delayed; D007074:Immunoglobulin G / Q000378:metabolism; D007249:Inflammation / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D019041:L-Selectin / Q000378:metabolism*; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D015394:Molecular Structure; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs / Q000187:drug effects*; D054852:Small Molecule Libraries
D000893:Anti-Inflammatory Agents; D002351:Carrageenan; D018925:Chemokines; D016207:Cytokines; D006025:Glycosaminoglycans; D006493:Heparin; D006497:Heparan Sulfate; D007074:Immunoglobulin G; D019041:L-Selectin; D054852:Small Molecule Libraries
Cytokine; DTH; GAG; Glycosaminoglycan; HS-GAG; Heparan sulfate; Heparin binding protein; Inflammation; L-selectin; SMIG or SMIGs; VEGF; delayed-type hypersensitivity; glycosaminoglycan; heparan sulfate; small molecule inhibitors of protein interaction with glycosaminoglycans; vascular endothelial growth factor