title: In silico design and bioevaluation of selective benzotriazepine BRD4 inhibitors with potent antiosteoclastogenic activity.
abstract: The bromodomain (BRD) and extra-terminal domain (BET) protein family bind to acetylated histones on lysine residues and act as epigenetic readers. Recently, the role of this protein family in bone loss has been gaining attention. Earlier studies have reported that benzotriazepine (Bzt) derivatives could be effective inhibitors of BET proteins. In this study, using in silico tools we designed three Bzt analogs (W49, W51, and W52). By docking, molecular simulations, and chemiluminescent Alpha Screen binding assay, we show that the studied analogs were selective at inhibiting BRD4 when compared to BRD2. Furthermore, we tested the effectiveness of these analogs on osteoclast formation and function. Among the examined analogs, Bzt-W49 and Bzt-W52 were found to be the most potent inhibitors of osteoclastogenesis without cytotoxicity in murine RAW264.7 osteoclast progenitors. Both the compounds also inhibited osteoclast formation without affecting cell viability in human CD14+ monocytes. Moreover, owing to attenuated osteoclastogenesis, actin ring formation and bone resorptive function of osteoclasts were severely perturbed. In conclusion, these results suggest that the novel BRD4-selective Bzt analogs designed in this study could be explored further for developing therapeutics against bone loss diseases characterized by excessive osteoclast activity.
authors.affiliation: Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
authors.forename: Vishwa
authors.initials: V
authors.lastname: Deepak
authors.affiliation: WuXi AppTec (Wuhan) Company Ltd., Wuhan, China.
authors.forename: Binglin
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa.
authors.forename: Dwayne
authors.initials: D
authors.lastname: Koot
authors.affiliation: Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
authors.forename: Abe
authors.initials: A
authors.lastname: Kasonga
authors.affiliation: Department of General Surgery, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
authors.forename: Xiao Xing
authors.initials: XX
authors.lastname: Stander
authors.affiliation: Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.|Institute for Food, Nutrition and Well-being, University of Pretoria, Pretoria, South Africa.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Coetzee
authors.affiliation: Department of Physiology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa.
authors.forename: Andre
authors.identifier: 0000-0002-3083-2997
authors.initials: A
authors.lastname: Stander
mesh_terms: D008841:Actin Cytoskeleton / Q000187:drug effects; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation / Q000187:drug effects; D018360:Crystallography, X-Ray; D015195:Drug Design; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D051379:Mice; D062105:Molecular Docking Simulation; D009000:Monocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D017434:Protein Structure, Tertiary; D000067996:RAW 264.7 Cells; D013816:Thermodynamics; D014157:Transcription Factors / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014227:Triazines / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D000092468:Bromodomain Containing Proteins
chemical_list: D018950:Lipopolysaccharide Receptors; D009687:Nuclear Proteins; D014157:Transcription Factors; D014227:Triazines; C486694:Brd4 protein, mouse; D000092468:Bromodomain Containing Proteins
keywords: 
  molecular modeling
  ; 
  structure-based drug design
  ; mechanism-based drug design