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Xie WY, Ji ZH, Ren WZ, Zhao PS, Wei FH, Hu J, Yuan B, Gao W. Wheat peptide alleviates DSS-induced colitis by activating the Keap1-Nrf2 signaling pathway and maintaining the integrity of the gut barrier. Food Funct 2024. [PMID: 38690672 DOI: 10.1039/d3fo04413k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Inflammatory bowel disease (IBD) is difficult to cure, and formulating a dietary plan is an effective means to prevent and treat this disease. Wheat peptide contains a variety of bioactive peptides with anti-inflammatory and antioxidant functions. The results of this study showed that preventive supplementation with wheat peptide (WP) can significantly alleviate the symptoms of dextran sulfate sodium (DSS)-induced colitis in mice. WP can increase body weight, alleviate colon shortening, and reduce disease activity index (DAI) scores. In addition, WP improved intestinal microbial disorders in mice with colitis. Based on LC-MS, a total of 313 peptides were identified in WP, 4 of which were predicted to be bioactive peptides. The regulatory effects of WP and four bioactive peptides on the Keap1-Nrf2 signaling pathway were verified in Caco-2 cells. In conclusion, this study demonstrated that WP alleviates DSS-induced colitis by helping maintain gut barrier integrity and targeting the Keap1-Nrf2 axis; these results provided a rationale for adding WP to dietary strategies to prevent IBD.
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Affiliation(s)
- Wen-Yin Xie
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
| | - Zhong-Hao Ji
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
- Department of Basic Medicine, Changzhi Medical College, Changzhi 046000, Shanxi, China
| | - Wen-Zhi Ren
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
| | - Pei-Sen Zhao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
| | - Fan-Hao Wei
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
| | - JinPing Hu
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
| | - Bao Yuan
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
| | - Wei Gao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, Jilin, China.
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Ma YR, Gao W, Wang HQ, Zhao PS, Zhang YX, Wei FH, Jiang H, Zhang JB, Yuan B, Gao F. EGF-driven EGFR/miR-27b-3p/FOXO1 promotes rat FSH synthesis and secretion. FASEB J 2024; 38:e23469. [PMID: 38358361 DOI: 10.1096/fj.202301970r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/04/2024] [Accepted: 01/23/2024] [Indexed: 02/16/2024]
Abstract
The adenopituitary secretes follicle-stimulating hormone (FSH), which plays a crucial role in regulating the growth, development, and reproductive functions of organisms. Investigating the process of FSH synthesis and secretion can offer valuable insights into potential areas of focus for reproductive research. Epidermal growth factor (EGF) is a significant paracrine/autocrine factor within the body, and studies have demonstrated its ability to stimulate FSH secretion in animals. However, the precise mechanisms that regulate this action are still poorly understood. In this research, in vivo and in vitro experiments showed that the activation of epidermal growth factor receptor (EGFR) by EGF induces the upregulation of miR-27b-3p and that miR-27b-3p targets and inhibits Foxo1 mRNA expression, resulting in increased FSH synthesis and secretion. In summary, this study elucidates the precise molecular mechanism through which EGF governs the synthesis and secretion of FSH via the EGFR/miR-27b-3p/FOXO1 pathway.
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Affiliation(s)
- Yi-Ran Ma
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Wei Gao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Hao-Qi Wang
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Pei-Sen Zhao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Yu-Xin Zhang
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Fan-Hao Wei
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Hao Jiang
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Jia-Bao Zhang
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Bao Yuan
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
| | - Fei Gao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun, Jilin, P.R. China
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Ji ZH, Xie WY, Zhao PS, Wu HY, Ren WZ, Hu JP, Gao W, Yuan B. Oat Peptides Alleviate Dextran Sulfate Sodium Salt-Induced Colitis by Maintaining the Intestinal Barrier and Modulating the Keap1-Nrf2 Axis. Nutrients 2023; 15:5055. [PMID: 38140314 PMCID: PMC10746067 DOI: 10.3390/nu15245055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/06/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
The prevalence of inflammatory bowel disease (IBD) is progressively rising each year, emphasizing the significance of implementing rational dietary interventions for disease prevention. Oats, being a staple agricultural product, are abundant in protein content. This study aimed to investigate the protective effects and underlying mechanisms of oat peptides (OPs) in a mouse model of acute colitis induced by dextran sulfate sodium salt (DSS) and a Caco-2 cell model. The findings demonstrated that intervention with OPs effectively mitigated the symptoms associated with DSS-induced colitis. The physicochemical characterization analysis demonstrated that the molecular weight of the OPs was predominantly below 5 kDa, with a predominant composition of 266 peptides. This study provides further evidence of the regulatory impact of OPs on the Keap1-Nrf2 signaling axis and elucidates the potential role of WGVGVRAERDA as the primary bioactive peptide responsible for the functional effects of OPs. Ultimately, the results of this investigation demonstrate that OPs effectively mitigate DSS-induced colitis by preserving the integrity of the intestinal barrier and modulating the Keap1-Nrf2 axis. Consequently, these findings establish a theoretical foundation for the utilization of OPs as dietary supplements to prevent the onset of IBD.
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Affiliation(s)
- Zhong-Hao Ji
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
- Department of Basic Medicine, Changzhi Medical College, Changzhi 046000, China
| | - Wen-Yin Xie
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
| | - Pei-Sen Zhao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
| | - Hong-Yu Wu
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
- Jilin Academy of Agricultural Sciences, Jilin 132101, China
| | - Wen-Zhi Ren
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
| | - Jin-Ping Hu
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
| | - Wei Gao
- Changchun National Experimental Animal Center, Jilin University, Changchun 130062, China
| | - Bao Yuan
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China; (Z.-H.J.); (W.-Y.X.); (P.-S.Z.); (H.-Y.W.); (W.-Z.R.); (J.-P.H.)
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4
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Ji ZH, He S, Xie WY, Zhao PS, Ren WZ, Gao W, Yuan B. Agaricus blazei Polysaccharide Alleviates DSS-Induced Colitis in Mice by Modulating Intestinal Barrier and Remodeling Metabolism. Nutrients 2023; 15:4877. [PMID: 38068735 PMCID: PMC10707896 DOI: 10.3390/nu15234877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/15/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Ulcerative colitis (UC) is a chronic noninfectious intestinal disease that severely affects patients' quality of life. Agaricus blazei Murrill polysaccharide (ABP) is an effective active ingredient extracted from Agaricus blazei Murrill (ABM). It has good efficacy in inhibiting tumor cell growth, lowering blood pressure, and improving atherosclerosis. However, its effect on colitis is unclear. The aim of this study was to analyze the protective effects and potential mechanisms of ABP against dextran sulfate sodium (DSS)-induced acute colitis in mice. The results showed that dietary supplementation with ABP significantly alleviated DSS-induced colitis symptoms, inflammatory responses, and oxidative stress. Meanwhile, ABP intervention was able to maintain the integrity of the intestinal mechanical barrier by promoting the expression of ZO-1 and Occludin tight junction proteins and facilitating mucus secretion. Moreover, 16S rRNA sequencing results suggested that ABP intervention was able to alleviate DSS-induced gut microbiota disruption, and nontargeted metabolomics results indicated that ABP was able to remodel metabolism. In conclusion, these results demonstrate that dietary supplementation with ABP alleviated DSS-induced acute colitis by maintaining intestinal barrier integrity and remodeling metabolism. These results improve our understanding of ABP function and provide a theoretical basis for the use of dietary supplementation with ABP for the prevention of ulcerative colitis.
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Affiliation(s)
- Zhong-Hao Ji
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
- Department of Basic Medicine, Changzhi Medical College, Changzhi 046000, China
| | - Song He
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
| | - Wen-Yin Xie
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
| | - Pei-Sen Zhao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
| | - Wen-Zhi Ren
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
| | - Wei Gao
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
| | - Bao Yuan
- Department of Laboratory Animals, College of Animal Sciences, Jilin University, Changchun 130062, China
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5
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Wang T, Wang HQ, Yuan B, Zhao GK, Ma YR, Zhao PS, Xie WY, Gao F, Gao W, Ren WZ. Integrative Proteomics and Phosphoproteomics Analysis of the Rat Adenohypophysis after GnRH Treatment. Int J Mol Sci 2023; 24:ijms24043339. [PMID: 36834752 PMCID: PMC9961725 DOI: 10.3390/ijms24043339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/27/2023] [Accepted: 02/05/2023] [Indexed: 02/11/2023] Open
Abstract
The regulation of mammalian reproductive activity is tightly dependent on the HPG axis crosstalk, in which several reproductive hormones play important roles. Among them, the physiological functions of gonadotropins are gradually being uncovered. However, the mechanisms by which GnRH regulates FSH synthesis and secretion still need to be more extensively and deeply explored. With the gradual completion of the human genome project, proteomes have become extremely important in the fields of human disease and biological process research. To explore the changes of protein and protein phosphorylation modifications in the adenohypophysis after GnRH stimulation, proteomics and phosphoproteomics analyses of rat adenohypophysis after GnRH treatment were performed by using TMT markers, HPLC classification, LC/MS, and bioinformatics analysis in this study. A total of 6762 proteins and 15,379 phosphorylation sites contained quantitative information. Twenty-eight upregulated proteins and fifty-three downregulated proteins were obtained in the rat adenohypophysis after GnRH treatment. The 323 upregulated phosphorylation sites and 677 downregulated phosphorylation sites found in the phosphoproteomics implied that a large number of phosphorylation modifications were regulated by GnRH and were involved in FSH synthesis and secretion. These data constitute a protein-protein phosphorylation map in the regulatory mechanism of "GnRH-FSH," which provides a basis for future studies on the complex molecular mechanisms of FSH synthesis and secretion. The results will be helpful for understanding the role of GnRH in the development and reproduction regulated by the pituitary proteome in mammals.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Wei Gao
- Correspondence: (W.G.); (W.-Z.R.)
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Ding J, Zhang YF, Zhao PS, Tang M, Xiao ZM, Zhang WH, Zhang HT, Yu ZJ, Du X, Li LW, Yuan J, Feng YC. Comparison of size-resolved hygroscopic growth factors of urban aerosol by different methods in Tianjin during a haze episode. Sci Total Environ 2019; 678:618-626. [PMID: 31078852 DOI: 10.1016/j.scitotenv.2019.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/16/2019] [Accepted: 05/01/2019] [Indexed: 06/09/2023]
Abstract
Size-resolved hygroscopic growth factors of urban aerosol during a haze episode were measured using a Humidified Tandem Differential Mobility Analyzer (HTDMA) (gm(RH)). These factors were also derived from size-resolved particulate chemical composition combined with the κ-Köhler theory (gκ(RH)) and the thermodynamic model ISORROPIA-II running in forward mode (giso-f(RH)) and reverse mode (giso-r(RH)), respectively. In terms of agreement among these hygroscopic growth factors, gκ(RH) matched gm(RH) best, followed by giso-r(RH). In contrast, giso-f(RH) demonstrated a poorer agreement with gm(RH). The good consistency among gm(RH), gκ(RH), and giso-r(RH) was because they only focus on the physical hygroscopic process, whereas giso-f(RH) contains not only the direct influence of relative humidity (RH) on particle size but also the influence of gaseous precursor on the particle chemical composition, which indirectly affects the hygroscopicity of the particles. In this sense, size-resolved gκ(RH) and giso-r(RH) in a wide size range are more adequate to investigate the impact of RH on light scattering and aerosol radiative forcing. At RH = 80%, gκ(RH) for accumulation mode particles was 1.30-1.45 on polluted days and higher than that on clean days (1.2-1.3). Whereas on both polluted and clean days, gκ(RH) of ultrafine and coarse mode particles were generally lower than 1.25. The strong hygroscopicity of accumulation mode particles observed on polluted days can deteriorate visibility due to their high extinction efficiency.
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Affiliation(s)
- J Ding
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Y F Zhang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - P S Zhao
- Institute of Urban Meteorology, China Meteorological Administration, Beijing, China.
| | - M Tang
- Tianjin Environmental Monitoring Center, Tianjin, China
| | - Z M Xiao
- Tianjin Environmental Monitoring Center, Tianjin, China
| | - W H Zhang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - H T Zhang
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Z J Yu
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - X Du
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China; Institute of Urban Meteorology, China Meteorological Administration, Beijing, China
| | - L W Li
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - J Yuan
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China
| | - Y C Feng
- State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, China.
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7
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Zhao PS. [Personal opinion on the formation of Chinese medicine] (Chi). Zhonghua Yi Shi Za Zhi 2001; 21:1-5. [PMID: 11612766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Voigt S, Hanspal M, LeRoy PJ, Zhao PS, Oh SS, Chishti AH, Liu SC. The cytoadherence ligand Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) binds to the P. falciparum knob-associated histidine-rich protein (KAHRP) by electrostatic interactions. Mol Biochem Parasitol 2000; 110:423-8. [PMID: 11071296 DOI: 10.1016/s0166-6851(00)00281-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S Voigt
- Department of Medicine, St Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA, USA.
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Affiliation(s)
- S S Raj
- X-ray Crystallography Unít, School of Physics, Universiti Sains Malaysia, Penang, Malaysia
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Shanmuga Sundara Raj S, Razak IA, Fun HK, Zhao PS, Jian F, Yang X, Lu L, Wang X. Tris(8-quinolinolato-N,O)cobalt(III) ethanol solvate. Acta Crystallogr C 2000; 56:E130-1. [PMID: 15263175 DOI: 10.1107/s0108270100003516] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2000] [Accepted: 03/03/2000] [Indexed: 11/10/2022] Open
Abstract
In the crystal of the title complex, [Co(C(9)H(6)NO)(3)].C(2)H(5)OH, the central Co atom has a distorted octahedral coordination comprised of three N atoms and three O atoms from the three 8-quinolinolato ligands. The three Co-O bond distances are in the range 1.887 (2)-1.910 (2) A, while the three Co-N bond distances range from 1.919 (2) to 1.934 (2) A. The solvent ethanol molecule forms an intermolecular O-H.O hydrogen bonding with a quinolinolato ligand.
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Affiliation(s)
- S Shanmuga Sundara Raj
- X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
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Zapf JW, Zhao PS, Steadman DJ, Berger SH. Genetic complementation and resistance to 5-fluoro-2'-deoxyuridine in thymidine auxotrophs expressing a highly defective mutant of human thymidylate synthase. Biochem Pharmacol 1999; 58:973-81. [PMID: 10509749 DOI: 10.1016/s0006-2952(99)00187-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A mutant human thymidylate synthase (TS) has been created in which a glutamine residue at position 214 has been replaced by glutamate. Glutamine at position 214 is postulated to be involved in maintaining the enzyme in a conformation that facilitates the binding of the substrate dUMP. Although the kcat/Km of the mutant protein for the substrate, dUMP, is 10(3) lower than that of wild-type TS, the mutant TS confers thymidine prototrophy on a TS-deficient bacterial strain when expressed at high levels. In the present investigation, a TS-deficient Chinese hamster lung cell line was transfected with DNA encoding the defective protein. Thymidine prototrophs were isolated that expressed the defective protein at levels that were physiologically relevant. The activities of the enzymes expressed endogenously in representative prototrophs were consistent with the activities observed for the purified proteins. At similar levels of TS expression, thymidine prototrophs expressing Glu214 TS were 8-fold more resistant to 5-fluoro-2'-deoxyuridine (FdUrd) cytotoxicity than are prototrophs expressing Gln214 TS. FdUrd is a prodrug of the tight-binding TS inhibitor, 5-fluoro-2'-deoxyuridine-5'-monophosphate (FdUMP). The resistance to FdUrd was associated with a significant decrease in the binding of FdUMP to the purified mutant enzyme. The data are consistent with the interpretation that TSs that are highly defective are capable of sufficient dTMP production for cell survival and optimal growth, yet may confer resistance to TS-directed inhibitors.
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Affiliation(s)
- J W Zapf
- Department of Basic Pharmaceutical Sciences, University of South Carolina, Columbia 29208, USA
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Abstract
Studies of the crystal structures of thymidylate synthase (TS) have revealed that a kink is present in beta-sheets that form the core of the enzyme. The beta-kink is proposed to serve as a "hinge" during conformational changes that occur in the enzyme after ligand binding at the active site. A residue in one of the beta-bulges that form the kink, glutamine at position 214 of human TS, is highly conserved in all TSs and is postulated to interact with nucleotide ligands that bind at the active site. To examine the role of this residue, glutamine at position 214 was replaced by residues that differ in volume, hydrophobicity, electrostatic charge, and hydrogen bonding potential. Genetic complementation studies utilizing a TS-deficient bacterial strain revealed that residues with large side chain volumes or that are prohibited in beta-bulges created loss of function proteins. Kinetic studies indicated that residue hydrophobicity is not correlated with catalytic activity. Residues that are predicted to alter the charge at position 214 created enzymes with kcat/Km values at least 10(3) lower than those of the wild type. Kinetic and ligand binding studies indicated that residue 214 is involved in nucleotide binding; however, hydrogen bonding potential does not contribute significantly to nucleotide binding energy. The data are consistent with the hypothesis that residue 214 is involved in maintaining the enzyme in a conformation that facilitates nucleotide binding and catalysis.
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Affiliation(s)
- D J Steadman
- Department of Chemistry, University of South Carolina, Columbia 29208, USA
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Zhao PS. [Fang Yizhi's idea and his medical discourses] (Chi). Zhonghua Yi Shi Za Zhi 1993; 23:65-8. [PMID: 11613137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
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14
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Zhao PS. [The fine tradition of Chinese medicine in the assimilation of foreign medicine]. Zhong Xi Yi Jie He Za Zhi 1982; 2:55-6. [PMID: 6219806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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