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Browsing by Author "Fei, Xiang"
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Item Chemical Proteomics Reveals Soluble Epoxide Hydrolase as a Therapeutic Target for Ocular Neovascularization(ACS, 2018) Sulaiman, Rania S.; Park, Bomina; Sardar Pasha, Sheik Pran Babu; Si, Yubing; Kharwadkar, Rakshin; Mitter, Sayak K.; Lee, Bit; Sun, Wei; Qi, Xiaoping; Boulton, Michael E.; Meroueh, Samy; Fei, Xiang; Seo, Seung-Yong; Corson, Timothy W.; Ophthalmology, School of MedicineThe standard-of-care therapeutics for the treatment of ocular neovascular diseases like wet age-related macular degeneration (AMD) are biologics targeting vascular endothelial growth factor signaling. There are currently no FDA approved small molecules for treating these blinding eye diseases. Therefore, therapeutic agents with novel mechanisms are critical to complement or combine with existing approaches. Here, we identified soluble epoxide hydrolase (sEH), a key enzyme for epoxy fatty acid metabolism, as a target of an antiangiogenic homoisoflavonoid, SH-11037. SH-11037 inhibits sEH in vitro and in vivo and docks to the substrate binding cleft in the sEH hydrolase domain. sEH levels and activity are up-regulated in the eyes of a choroidal neovascularization (CNV) mouse model. sEH is overexpressed in human wet AMD eyes, suggesting that sEH is relevant to neovascularization. Known sEH inhibitors delivered intraocularly suppressed CNV. Thus, by dissecting a bioactive compound’s mechanism, we identified a new chemotype for sEH inhibition and characterized sEH as a target for blocking the CNV that underlies wet AMD.Item Design, synthesis and biological evaluation of photoaffinity probes of antiangiogenic homoisoflavonoids(Elsevier, 2016-09) Lee, Bit; Sun, Wei; Lee, Hyungjun; Basavarajappa, Halesha; Sulaiman, Rania S.; Sishtla, Kamakshi; Fei, Xiang; Corson, Timothy W.; Seo, Seung-Yong; Department of Ophthalmology, IU School of MedicineA naturally occurring homoisoflavonoid, cremastranone (1) inhibited angiogenesis in vitro and in vivo. We developed an analogue SH-11037 (2) which is more potent than cremastranone in human retinal microvascular endothelial cells (HRECs) and blocks neovascularization in animal models. Despite their efficacy, the mechanism of these compounds is not yet fully known. In the course of building on a strong foundation of SAR and creating a novel chemical tool for target identification of homoisoflavonoid-binding proteins, various types of photoaffinity probes were designed and synthesized in which benzophenone and biotin were attached to homoisoflavanonoids using PEG linkers on either the C-3′ or C-7 position. Notably, the photoaffinity probes linking on the phenol group of the C-3′ position retain excellent activity of inhibiting retinal endothelial cell proliferation with up to 72 nM of GI50.Item Enantioselective Synthesis of Homoisoflavanones by Asymmetric Transfer Hydrogenation and Their Biological Evaluation for Antiangiogenic Activity(ACS Publications, 2019-08-05) Heo, Myunghoe; Lee, Bit; Sishtla, Kamakshi; Fei, Xiang; Lee, Sanha; Park, Soojun; Yuan, Yue; Lee, Seul; Kwon, Sangil; Lee, Jungeun; Kim, Sanghee; Corson, Timothy W.; Seo, Seung-Yong; Ophthalmology, School of MedicineNeovascular eye diseases are a major cause of blindness. Excessive angiogenesis is a feature of several conditions, including wet age-related macular degeneration, proliferative diabetic retinopathy, and retinopathy of prematurity. Development of novel anti-angiogenic small molecules for the treatment of neovascular eye disease is essential to provide new therapeutic leads for these diseases. We have previously reported the therapeutic potential of anti-angiogenic homoisoflavanone derivatives with efficacy in retinal and choroidal neovascularization models, although these are racemic compounds due to the C3-stereogenic center in the molecules. This work presents asymmetric synthesis and structural determination of anti-angiogenic homoisoflavanones and pharmacological characterization of the stereoisomers. We describe an enantioselective synthesis of homoisoflavanones by virtue of ruthenium-catalyzed asymmetric transfer hydrogenation accompanying dynamic kinetic resolution, providing a basis for the further development of these compounds into novel experimental therapeutics for neovascular eye diseases.Item The first synthesis of the antiangiogenic homoisoflavanone, cremastranone(Royal Society of Chemistry, 2014-10-21) Lee, Bit; Basavarajappa, Halesha D.; Sulaiman, Rania S.; Fei, Xiang; Seo, Seung-Yong; Corson, Timothy W.; Department of Ophthalmology, IU School of MedicineAn antiangiogenic homoisoflavanone, cremastranone, was synthesized for the first time. This scalable synthesis, which includes selective demethylation, could be used to develop lead molecules to treat angiogenesis-induced eye diseases. Synthetic cremastranone inhibited the proliferation, migration and tube formation ability of human retinal microvascular endothelial cells, important steps in pathological angiogenesis.Item The First Synthesis of the Antiangiogenic Homoisoflavanone, Cremastranone(Royal Society of Chemistry, 2014) Lee, Bit; Basavarajappa, Halesha D.; Sulaiman, Rania S.; Fei, Xiang; Seo, Seung-Yong; Corson, Timothy W.; Department of Ophthalmology, IU School of MedicineAn antiangiogenic homoisoflavanone, cremastranone, was synthesized for the first time. This scalable synthesis, which includes selective demethylation, could be used to develop lead molecules to treat angiogenesis-induced eye diseases. Synthetic cremastranone inhibited the proliferation, migration and tube formation ability of human retinal microvascular endothelial cells, important steps in pathological angiogenesis.Item Synthesis and Mechanistic Studies of a Novel Homoisoflavanone Inhibitor of Endothelial Cell Growth(2014-04) Basavarajappa, Halesha D; Lee, Bit; Fei, Xiang; Lim, Daesung; Callaghan, Breedge; Mund, Julie A; Case, Jamie; Rajashekhar, Gangaraju; Seo, Seung-Yong; Corson, Timothy W.Preventing pathological ocular angiogenesis is key to treating retinopathy of prematurity, diabetic retinopathy and age-related macular degeneration. At present there is no small molecule drug on the market to target this process and hence there is a pressing need for developing novel small molecules that can replace or complement the present surgical and biologic therapies for these neovascular eye diseases. Previously, an antiangiogenic homoisoflavanone was isolated from the bulb of a medicinal orchid, Cremastra appendiculata. In this study, we present the synthesis of a novel homoisoflavanone isomer of this compound. Our compound, SH-11052, has antiproliferative activity against human umbilical vein endothelial cells, and also against more ocular disease-relevant human retinal microvascular endothelial cells (HRECs). Tube formation and cell cycle progression of HRECs were inhibited by SH-11052, but the compound did not induce apoptosis at effective concentrations. SH-11052 also decreased TNF-α induced p38 MAPK phosphorylation in these cells. Intriguingly, SH-11052 blocked TNF-α induced IκB-α degradation, and therefore decreased NF-κB nuclear translocation. It decreased the expression of NF-κB target genes and the pro-angiogenic or pro-inflammatory markers VCAM-1, CCL2, IL8, and PTGS2. In addition SH-11052 inhibited VEGF induced activation of Akt but not VEGF receptor autophosphorylation. Based on these results we propose that SH-11052 inhibits inflammation induced angiogenesis by blocking both TNF-α and VEGF mediated pathways, two major pathways involved in pathological angiogenesis. Synthesis of this novel homoisoflavanone opens the door to structure-activity relationship studies of this class of compound and further evaluation of its mechanism and potential to complement existing antiangiogenic drugs.Item Total Synthesis of Naturally Occurring 5,7,8-Trioxygenated Homoisoflavonoids(American Chemical Society, 2020-05-06) Kwon, Sangil; Lee, Sanha; Heo, Myunghoe; Lee, Bit; Fei, Xiang; Corson, Timothy W.; Seo, Seung-Yong; Ophthalmology, School of MedicineHomoisoflavonoids are in the subclass of the larger family of flavonoids but have one more alkyl carbon than flavonoids. Among them, 5,7,8-trioxygenated homoisoflavonoids have not been extensively studied for synthesis and biological evaluation. Our current objective is to synthesize 2 5,7,8-trioxygenated chroman-4-ones and 12 5,7,8-trioxygenated homoisoflavonoids that have been isolated from the plants Bellevalia eigii, Drimiopsis maculata, Ledebouria graminifolia, Eucomis autumnalis, Eucomis punctata, Eucomis pallidiflora, Chionodoxa luciliae, Muscari comosum, and Dracaena cochinchinensis. For this purpose, 1,3,4,5-tetramethoxybenzene and 4'-benzyloxy-2',3'-dimethoxy-6'-hydroxyacetophenone were used as starting materials. Asymmetric transfer hydrogenation using Noyori's Ru catalyst provided 5,7,8-trioxygenated-3-benzylchroman-4-ones with R-configuration in high yield and enantiomeric excess. By selective deprotection of homoisoflavonoids using BCl3, the total synthesis of natural products including 10 first syntheses and three asymmetric syntheses has been completed, and three isomers of the reported dracaeconolide B could be provided. Our research on 5,7,8-trioxygenated homoisoflavonoids would be useful for the synthesis of related natural products and pharmacological applications.