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Svrcina H, Greer A, Baker S, Smith M, Martinez P, Granger N, Thomas N, Miller J, Steinke E, Davitt K, Sloane E, Nugent L, Sabo R, Williams C, Lipton MA, Jones D. Death effects of reveromycin A in normal and disease-associated cells of the joint. J Cell Biochem 2017; 119:4382-4396. [PMID: 29077233 DOI: 10.1002/jcb.26463] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/24/2017] [Indexed: 11/09/2022]
Abstract
Earlier work in our laboratory demonstrated that naturally occurring reveromycin A (Rev A) causes apoptosis in osteoclasts without accompanying necrosis. Rev A death effects in both normal and diseased joint cells were investigated in this study. A dose of 10 μM Rev A did not cause apoptosis nor necrosis in monolayer chondrocytes, even at pH 6.8, a pH mimicking that of an inflamed joint. In contrast, at the acidic pH Rev A did induce significant apoptosis (fourfold increase at 48 h of treatment, P < 0.005) in normal synoviocytes without accompanying necrosis. Western blot of the normal synoviocyte proteins revealed that cytochrome c levels were not significantly changed over the time course of treatment nor did caspase 8 activity increase; therefore, Rev A appears to exert this apoptotic effect through a mechanism independent of the classical intrinsic and extrinsic pathways. Fibroblast-like synoviocytes isolated from rheumatoid arthritis patients (RAFLS) as well as normal human fibroblast-like synoviocytes (NHFLS), cells known to play key roles in arthritic joint pathology, were also subjected to Rev A treatment at both physiologic and acidic pH's. Neither apoptosis nor necrosis was induced in either RAFLS or NHFLS. Parallel mitomycin C treatment of NHFLS induced both apoptosis and necrosis. Comparative structure-activity analyses of Rev A and mitomycin C revealed that Rev A is less likely to cross the cell membrane at near neutral pH. Collectively the data reveal that a physiological dose of Rev A under acidic conditions induces normal synoviocytes to undergo apoptosis while pathologic fibroblast-like synoviocytes are resistant to apoptosis and necrosis.
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Affiliation(s)
- Haley Svrcina
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Austin Greer
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Seth Baker
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Morgan Smith
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Patricia Martinez
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Nathan Granger
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Natassja Thomas
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Jaylin Miller
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Ellen Steinke
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Kelsey Davitt
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Emily Sloane
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Lauren Nugent
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Ryan Sabo
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Calli Williams
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
| | - Mark A Lipton
- Department of Chemistry, Purdue University, West Lafayette, Indiana
| | - Daniel Jones
- Division of Natural Sciences, Department of Biology, Indiana Wesleyan University, Marion, Indiana
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Abstract
Oxidative cyclizations are important transformations that occur widely during natural product biosynthesis. The transformations from acyclic precursors to cyclized products can afford morphed scaffolds, structural rigidity, and biological activities. Some of the most dramatic structural alterations in natural product biosynthesis occur through oxidative cyclization. In this Review, we examine the different strategies used by nature to create new intra(inter)molecular bonds via redox chemistry. This Review will cover both oxidation- and reduction-enabled cyclization mechanisms, with an emphasis on the former. Radical cyclizations catalyzed by P450, nonheme iron, α-KG-dependent oxygenases, and radical SAM enzymes are discussed to illustrate the use of molecular oxygen and S-adenosylmethionine to forge new bonds at unactivated sites via one-electron manifolds. Nonradical cyclizations catalyzed by flavin-dependent monooxygenases and NAD(P)H-dependent reductases are covered to show the use of two-electron manifolds in initiating cyclization reactions. The oxidative installations of epoxides and halogens into acyclic scaffolds to drive subsequent cyclizations are separately discussed as examples of "disappearing" reactive handles. Last, oxidative rearrangement of rings systems, including contractions and expansions, will be covered.
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Affiliation(s)
- Man-Cheng Tang
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - Yi Zou
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
| | - Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Christopher T. Walsh
- Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford University, 443 Via Ortega, Stanford, CA 94305
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, Department of Chemistry and Biochemistry, University of California, Los Angeles, 420 Westwood Plaza, Los Angeles, CA 90095, USA
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