8dea
Scaffold Hopping via Ring Opening Enables Identification of Acyclic Compounds as New Complement Factor D Inhibitors
Structural highlights
DiseaseCFAD_HUMAN Defects in CFD are the cause of complement factor D deficiency (CFDD) [MIM:613912. CFDD is an immunologic disorder characterized by increased susceptibility to bacterial infections, particularly Neisseria infections, due to a defect in the alternative complement pathway. FunctionCFAD_HUMAN Factor D cleaves factor B when the latter is complexed with factor C3b, activating the C3bbb complex, which then becomes the C3 convertase of the alternate pathway. Its function is homologous to that of C1s in the classical pathway. Publication Abstract from PubMedThe three complement pathways comprising the early phase of the complement system (the classical, lectin, and alternative pathways) act together with the innate and adaptive immune systems to protect against foreign entities and maintain tissue homeostasis. While these systems are normally under tight regulatory control, several diseases have been reported to correlate with uncontrolled activation and amplification of the alternative pathway, including paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, C3 glomerulopathy, and age-related macular degeneration. Complement FactorD (CFD), a serine protease, is the rate-limiting enzyme for the activity of alternative pathway. CFD activates the alternative pathway by cleaving Complement Factor B complexed to C3b (C3bB) to generate alternative pathway C3 convertase (C3bBb). In our search for novel CFD inhibitors with therapeutic potential, we employed a hot-spot analysis of an ensemble of apo and holo CFD structures. This analysis identified potential pharmacophore features that aided in the design of a series of compounds based on an l-proline core. While these compounds inhibited CFD in an esterolytic assay (for example, a proline-based compound, IC50 = 161 nM), the pharmacokinetic (PK) properties were poor. A strategy of scaffold hopping via ring opening led to a novel series of acyclic compounds, with subsequent structure-based ligand design and lead optimization producing several novel CFD inhibitors. One of these inhibitors, 1-(2-((2-(3-chloro-2-fluorobenzylamino)-2-oxoethyl)(cyclopropyl)amino)-2-oxoethyl )-5-(3-methyl-3-(1-methylpiperidin-4-yl)ureido)-1H-indazole-3-carboxamide, showed good potency with IC50s of 37 nM in the esterolytic assay and 30 nM in a hemolytic assay and PK assessments following oral administration to rats revealed a Cmax of 113 ng/mL and an AUC0-24h of 257 hr.ng/mL. Scaffold hopping via ring opening enables identification of acyclic compounds as new complement Factor D inhibitors.,Zhang W, Wu M, Vadlakonda S, Juarez L, Cheng X, Muppa S, Chintareddy V, Vogeti L, Kellogg-Yelder D, Williams J, Polach K, Chen X, Raman K, Babu YS, Kotian P Bioorg Med Chem. 2022 Oct 9;74:117034. doi: 10.1016/j.bmc.2022.117034. PMID:36272185[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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