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Dai S, Wang Z, Cai M, Guo T, Mao S, Yang Y. A multi-omics investigation of the lung injury induced by PM 2.5 at environmental levels via the lung-gut axis. Sci Total Environ 2024; 926:172027. [PMID: 38552982 DOI: 10.1016/j.scitotenv.2024.172027] [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] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 02/25/2024] [Accepted: 03/25/2024] [Indexed: 04/05/2024]
Abstract
Long-term exposure to fine particulate matter (PM2.5) posed injury for gastrointestinal and respiratory systems, ascribing with the lung-gut axis. However, the cross-talk mechanisms remain unclear. Here, we attempted to establish the response networks of lung-gut axis in mice exposed to PM2.5 at environmental levels. Male Balb/c mice were exposed to PM2.5 (dose of 0.1, 0.5, and 1.0 mg/kg) collected from Chengdu, China for 10 weeks, through intratracheally instillation, and examined the effect of PM2.5 on lung functions of mice. The changes of lung and gut microbiota and metabolic profiles of mice in different groups were determined. Furthermore, the results of multi-omics were conjointly analyzed to elucidate the primary microbes and the associated metabolites in lung and gut responsible for PM2.5 exposure. Accordingly, the cross-talk network and key pathways between lung-gut axis were established. The results indicated that exposed to PM2.5 0.1 mg/kg induced obvious inflammations in mice lung, while emphysema was observed at 1.0 mg/kg. The levels of metabolites guanosine, hypoxanthine, and hepoxilin B3 increased in the lung might contribute to lung inflammations in exposure groups. For microbiotas in lung, PM2.5 exposure significantly declined the proportions of Halomonas and Lactobacillus. Meanwhile, the metabolites in gut including L-tryptophan, serotonin, and spermidine were up-regulated in exposure groups, which were linked to the decreasing of Oscillospira and Helicobacter in gut. Via lung-gut axis, the activations of pathways including Tryptophan metabolism, ABC transporters, Serotonergic synapse, and Linoleic acid metabolism contributed to the cross-talk between lung and gut tissues of mice mediated by PM2.5. In summary, the microbes including Lactobacillus, Oscillospira, and Parabacteroides, and metabolites including hepoxilin B3, guanosine, hypoxanthine, L-tryptophan, and spermidine were the main drivers. In this lung-gut axis study, we elucidated some pro- and pre-biotics in lung and gut microenvironments contributed to the adverse effects on lung functions induced by PM2.5 exposure.
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Affiliation(s)
- Shuiping Dai
- National Center for Geriatrics Clinical Medicine Research, Department of Geriatrics and Gerontology, West China Hospital, Sichuan University, Chengdu 610041, PR China
| | - Zhenglu Wang
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, PR China.
| | - Min Cai
- Eco-environmental Protection Institute, Shanghai Academy of Agricultural Science, Shanghai 201403, PR China
| | - Tingting Guo
- Institute of Respiratory Health, West China Hospital, Sichuan University, Chengdu 610041, PR China
| | - Shengqiang Mao
- Institute of Respiratory Health, West China Hospital, Sichuan University, Chengdu 610041, PR China
| | - Ying Yang
- Institute of Respiratory Health, West China Hospital, Sichuan University, Chengdu 610041, PR China
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Cao S, Li Y, Song R, Meng X, Fuchs M, Liang C, Kachler K, Meng X, Wen J, Schlötzer-Schrehardt U, Taudte V, Gessner A, Kunz M, Schleicher U, Zaiss MM, Kastbom A, Chen X, Schett G, Bozec A. L-arginine metabolism inhibits arthritis and inflammatory bone loss. Ann Rheum Dis 2024; 83:72-87. [PMID: 37775153 PMCID: PMC10803985 DOI: 10.1136/ard-2022-223626] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [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: 11/14/2022] [Accepted: 08/29/2023] [Indexed: 10/01/2023]
Abstract
OBJECTIVES To investigate the effect of the L-arginine metabolism on arthritis and inflammation-mediated bone loss. METHODS L-arginine was applied to three arthritis models (collagen-induced arthritis, serum-induced arthritis and human TNF transgenic mice). Inflammation was assessed clinically and histologically, while bone changes were quantified by μCT and histomorphometry. In vitro, effects of L-arginine on osteoclast differentiation were analysed by RNA-seq and mass spectrometry (MS). Seahorse, Single Cell ENergetIc metabolism by profilIng Translation inHibition and transmission electron microscopy were used for detecting metabolic changes in osteoclasts. Moreover, arginine-associated metabolites were measured in the serum of rheumatoid arthritis (RA) and pre-RA patients. RESULTS L-arginine inhibited arthritis and bone loss in all three models and directly blocked TNFα-induced murine and human osteoclastogenesis. RNA-seq and MS analyses indicated that L-arginine switched glycolysis to oxidative phosphorylation in inflammatory osteoclasts leading to increased ATP production, purine metabolism and elevated inosine and hypoxanthine levels. Adenosine deaminase inhibitors blocking inosine and hypoxanthine production abolished the inhibition of L-arginine on osteoclastogenesis in vitro and in vivo. Altered arginine levels were also found in RA and pre-RA patients. CONCLUSION Our study demonstrated that L-arginine ameliorates arthritis and bone erosion through metabolic reprogramming and perturbation of purine metabolism in osteoclasts.
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Affiliation(s)
- Shan Cao
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
- Department of Rheumatology, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yixuan Li
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
- Department of Rheumatology, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Rui Song
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
- Department of Rheumatology, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xianyi Meng
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
| | - Maximilian Fuchs
- Chair of Medical Informatics, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | - Chunguang Liang
- Chair of Medical Informatics, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Bioinformatics, Biocenter, University of Würzburg Am Hubland, Würzburg, Germany
| | - Katerina Kachler
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
| | - Xinyu Meng
- Department of Rheumatology, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jinming Wen
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
- Cancer Center, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Ursula Schlötzer-Schrehardt
- Department of Ophthalmology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Verena Taudte
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Core Facility for Metabolomics, Department of Medicine, Philipps University of Marburg, Marburg, Germany
| | - Arne Gessner
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
| | - Meik Kunz
- Chair of Medical Informatics, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | - Ulrike Schleicher
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
| | - Mario M Zaiss
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
| | - Alf Kastbom
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Xiaoxiang Chen
- Department of Rheumatology, Renji Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Georg Schett
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
| | - Aline Bozec
- Department of Internal Medicine 3 - Rheumatology and Immunology, Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie (DZI), Friedrich-Alexander University (FAU) Erlangen-Nürnberg and Universitätsklinikum Erlangen, Erlangen, Shanghai, Germany
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Shakartalla SB, Ashmawy NS, Semreen MH, Fayed B, Al Shareef ZM, Jayakumar MN, Ibrahim S, Rahmani M, Hamdy R, Soliman SSM. 1H-NMR metabolomics analysis identifies hypoxanthine as a novel metastasis-associated metabolite in breast cancer. Sci Rep 2024; 14:253. [PMID: 38167685 PMCID: PMC10762038 DOI: 10.1038/s41598-023-50866-y] [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: 09/23/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024] Open
Abstract
Breast cancer is one of the leading causes of death in females, mainly because of metastasis. Oncometabolites, produced via metabolic reprogramming, can influence metastatic signaling cascades. Accordingly, and based on our previous results, we propose that metabolites from highly metastatic breast cancer cells behave differently from less-metastatic cells and may play a significant role in metastasis. For instance, we aim to identify these metabolites and their role in breast cancer metastasis. Less metastatic cells (MCF-7) were treated with metabolites secreted from highly metastatic cells (MDA-MB-231) and the gene expression of three epithelial-to-mesenchymal transition (EMT) markers including E-cadherin, N-cadherin and vimentin were examined. Some metabolites secreted from MDA-MB-231 cells significantly induced EMT activity. Specifically, hypoxanthine demonstrated a significant EMT effect and increased the migration and invasion effects of MCF-7 cells through a hypoxia-associated mechanism. Hypoxanthine exhibited pro-angiogenic effects via increasing the VEGF and PDGF gene expression and affected lipid metabolism by increasing the gene expression of PCSK-9. Notably, knockdown of purine nucleoside phosphorylase, a gene encoding for an important enzyme in the biosynthesis of hypoxanthine, and inhibition of hypoxanthine uptake caused a significant decrease in hypoxanthine-associated EMT effects. Collectively for the first time, hypoxanthine was identified as a novel metastasis-associated metabolite in breast cancer cells and represents a promising target for diagnosis and therapy.
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Affiliation(s)
- Sarra B Shakartalla
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- College of Medicine, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Faculty of Pharmacy, University of Gezira, P.O. Box. 21111, Wadmedani, Sudan
| | - Naglaa S Ashmawy
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Department of Pharmaceutical Sciences, College of Pharmacy, Gulf Medical University, P.O. Box 4184, Ajman, United Arab Emirates
- Department of Pharmacognosy, Faculty of Pharmacy, Ain Shams University, Abbassia, P.O. Box 11566, Cairo, Egypt
| | - Mohammad H Semreen
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
| | - Bahgat Fayed
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Chemistry of Natural and Microbial Product Department, National Research Centre, P.O. Box 12622, Cairo, Egypt
| | - Zainab M Al Shareef
- College of Medicine, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
| | - Manju N Jayakumar
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
| | - Saleh Ibrahim
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Center for Biotechnology, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Mohamed Rahmani
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Center for Biotechnology, Khalifa University, Abu Dhabi, United Arab Emirates
- College of Medicine and Health Sciences, Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
| | - Rania Hamdy
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates
- Faculty of Pharmacy, Zagazig University, P.O. Box 44519, Zagazig, Egypt
| | - Sameh S M Soliman
- Research Institute for Medical and Health Sciences, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates.
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, P.O. Box 27272, Sharjah, United Arab Emirates.
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Sun Q, Shen M, Zhu S, Liao Y, Zhang D, Sun J, Guo Z, Wu L, Xiao L, Liu L. Targeting NAD + metabolism of hepatocellular carcinoma cells by lenvatinib promotes M2 macrophages reverse polarization, suppressing the HCC progression. Hepatol Int 2023; 17:1444-1460. [PMID: 37204655 DOI: 10.1007/s12072-023-10544-7] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/22/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND Lowered nicotinamide adenine dinucleotide (NAD+) levels in tumor cells drive tumor hyperprogression during immunotherapy, and its restoration activates immune cells. However, the effect of lenvatinib, a first-line treatment for unresectable hepatocellular carcinoma (HCC), on NAD+ metabolism in HCC cells, and the metabolite crosstalk between HCC and immune cells after targeting NAD+ metabolism of HCC cells remain unelucidated. METHODS Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and ultra-high-performance liquid chromatography multiple reaction monitoring-mass spectrometry (UHPLC-MRM-MS) were used to detect and validate differential metabolites. RNA sequencing was used to explore mRNA expression in macrophages and HCC cells. HCC mouse models were used to validate the effects of lenvatinib on immune cells and NAD+ metabolism. The macrophage properties were elucidated using cell proliferation, apoptosis, and co-culture assays. In silico structural analysis and interaction assays were used to determine whether lenvatinib targets tet methylcytosine dioxygenase 2 (TET2). Flow cytometry was performed to assess changes in immune cells. RESULTS Lenvatinib targeted TET2 to synthesize and increase NAD+ levels, thereby inhibiting decomposition in HCC cells. NAD+ salvage increased lenvatinib-induced apoptosis of HCC cells. Lenvatinib also induced CD8+ T cells and M1 macrophages infiltration in vivo. And lenvatinib suppressed niacinamide, 5-Hydroxy-L-tryptophan and quinoline secretion of HCC cells, and increased hypoxanthine secretion, which contributed to proliferation, migration and polarization function of macrophages. Consequently, lenvatinib targeted NAD+ metabolism and elevated HCC-derived hypoxanthine to enhance the macrophages polarization from M2 to M1. Glycosaminoglycan binding disorder and positive regulation of cytosolic calcium ion concentration were characteristic features of the reverse polarization. CONCLUSIONS Targeting HCC cells NAD+ metabolism by lenvatinib-TET2 pathway drives metabolite crosstalk, leading to M2 macrophages reverse polarization, thereby suppressing HCC progression. Collectively, these novel insights highlight the role of lenvatinib or its combination therapies as promising therapeutic alternatives for HCC patients with low NAD+ levels or high TET2 levels.
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Affiliation(s)
- Qingcan Sun
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China
| | - Mengying Shen
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China
| | - Subin Zhu
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China
| | - Yanxia Liao
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China
| | - Dongyan Zhang
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Jingyuan Sun
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Zeqin Guo
- Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Leyuan Wu
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China
| | - Lushan Xiao
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China
| | - Li Liu
- Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
- State Key Laboratory of Organ Failure Research, Guangzhou, 510515, China.
- Guangdong Provincial Key Laboratory of Viral Hepatitis Research, Guangzhou, 510515, China.
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Jo JK, Lee G, Nguyen CD, Park SE, Kim EJ, Kim HW, Seo SH, Cho KM, Kwon SJ, Kim JH, Son HS. Effects of Donepezil Treatment on Brain Metabolites, Gut Microbiota, and Gut Metabolites in an Amyloid Beta-Induced Cognitive Impairment Mouse Pilot Model. Molecules 2022; 27:molecules27196591. [PMID: 36235127 PMCID: PMC9572896 DOI: 10.3390/molecules27196591] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/26/2022] [Accepted: 09/30/2022] [Indexed: 12/12/2022]
Abstract
Accumulated clinical and biomedical evidence indicates that the gut microbiota and their metabolites affect brain function and behavior in various central nervous system disorders. This study was performed to investigate the changes in brain metabolites and composition of the fecal microbial community following injection of amyloid β (Aβ) and donepezil treatment of Aβ-injected mice using metataxonomics and metabolomics. Aβ treatment caused cognitive dysfunction, while donepezil resulted in the successful recovery of memory impairment. The Aβ + donepezil group showed a significantly higher relative abundance of Verrucomicrobia than the Aβ group. The relative abundance of 12 taxa, including Blautia and Akkermansia, differed significantly between the groups. The Aβ + donepezil group had higher levels of oxalate, glycerol, xylose, and palmitoleate in feces and oxalate, pyroglutamic acid, hypoxanthine, and inosine in brain tissues than the Aβ group. The levels of pyroglutamic acid, glutamic acid, and phenylalanine showed similar changes in vivo and in vitro using HT-22 cells. The major metabolic pathways in the brain tissues and gut microbiota affected by Aβ or donepezil treatment of Aβ-injected mice were related to amino acid pathways and sugar metabolism, respectively. These findings suggest that alterations in the gut microbiota might influence the induction and amelioration of Aβ-induced cognitive dysfunction via the gut–brain axis. This study could provide basic data on the effects of Aβ and donepezil on gut microbiota and metabolites in an Aβ-induced cognitive impairment mouse model.
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Affiliation(s)
- Jae-Kwon Jo
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Gihyun Lee
- Department of Korean Medicine, Dongshin University, Naju 58245, Korea
| | - Cong Duc Nguyen
- Department of Korean Medicine, Dongshin University, Naju 58245, Korea
| | - Seong-Eun Park
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Eun-Ju Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | - Hyun-Woo Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
| | | | | | | | - Jae-Hong Kim
- Department of Acupuncture and Moxibustion Medicine, College of Korean Medicine, Dongshin University, Naju 58245, Korea
- Correspondence: (J.-H.K.); (H.-S.S.); Tel.: +82-62-350-7209 (J.-H.K.); +82-2-3290-3053 (H.-S.S.)
| | - Hong-Seok Son
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Korea
- Correspondence: (J.-H.K.); (H.-S.S.); Tel.: +82-62-350-7209 (J.-H.K.); +82-2-3290-3053 (H.-S.S.)
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Wang Z, Xiao H, Dong J, Li Y, Wang B, Chen Z, Zeng X, Liu J, Dong Y, Ma L, Xu J, Cheng L, Li C, Liu X, Cui M. Sexual dimorphism in gut microbiota dictates therapeutic efficacy of intravenous immunoglobulin on radiotherapy complications. J Adv Res 2022; 46:123-133. [PMID: 35700918 PMCID: PMC10105085 DOI: 10.1016/j.jare.2022.06.002] [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: 01/25/2022] [Revised: 05/16/2022] [Accepted: 06/07/2022] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION With the mounting number of cancer survivors, the complications following cancer treatment become novel conundrums and starve for countermeasures. Intravenous immunoglobulin (IVIg) is a purified preparation for immune-deficient and autoimmune conditions. OBJECTIVES Here, we investigated whether IVIg could be employed to fight against radiation injuries and explored the underlying mechanism. METHODS Hematopoietic or gastrointestinal (GI) tract toxicity was induced by total body or abdominal local irradiation. High-throughput sequencing was performed to analyze the gut microbiota configurations and gene expression profile of small intestine. The untargeted metabolomics of gut microbiome was assessed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses. Hydrodynamic-based gene delivery was used to knockdown the target genes in vivo. RESULTS Intravenous injection of IVIg protected against radiation-induced hematopoietic and GI tract toxicity in female mice but not in males. IVIg structured sex-characteristic gut microbiota configurations in abdominal irradiated mice. The irradiation enriched gut Lachnospiraceae in female mice but reduced those in males. IVIg injection combined with oral gavage of Lachnospiraceae or its metabolite hypoxanthine, alleviated radiation toxicity in male mice however, Lachnospiraceae or hypoxanthine alone failed to ameliorate the injuries. Abdominal local irradiation drove sex-distinct gene expression signatures in small intestine. Mechanistic investigation showed that replenishment of Lachnospiraceae or hypoxanthine offset abdominal radiation-reduced PLD1 expression in male mice. In females, irradiation elevated PLD1 expression. Deletion of PLD1 in GI tract of female mice erased the radioprotective effects of IVIg. CONCLUSION IVIg battles against radiation injuries in a sex-specific, gut microbiome-dependent way through Lachnospiraceae/hypoxanthine/PLD1 axis. Our findings provide a sex-precise therapeutic avenue to improve the prognosis of cancer patients with radiotherapy in pre-clinical settings.
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Affiliation(s)
- Zongkui Wang
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College, Chengdu, 610052, China
| | - Huiwen Xiao
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jiali Dong
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Yuan Li
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Bin Wang
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Zhiyuan Chen
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Xiaozhou Zeng
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Jia Liu
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Yanxi Dong
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Li Ma
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College, Chengdu, 610052, China
| | - Jun Xu
- Shanghai RAAS Blood products Co., Ltd., Shanghai, 201401, China
| | - Lu Cheng
- Shanghai RAAS Blood products Co., Ltd., Shanghai, 201401, China
| | - Changqing Li
- Institute of Blood Transfusion, Chinese Academy of Medical Sciences & Peking Union Medical College, Chengdu, 610052, China.
| | - Xingzhong Liu
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
| | - Ming Cui
- Tianjin Key Laboratory of Radiation Medicine and Molecular Nuclear Medicine, Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China.
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Lan W, Sun Y, Liu S, Guan Y, Zhu S, Xie J. Effects of ultrasound-assisted chitosan grafted caffeic acid coating on the quality and microbial composition of pompano during ice storage. Ultrason Sonochem 2022; 86:106032. [PMID: 35617884 PMCID: PMC9130226 DOI: 10.1016/j.ultsonch.2022.106032] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/25/2022] [Accepted: 05/06/2022] [Indexed: 05/27/2023]
Abstract
The effects of ultrasound-assisted chitosan grafted caffeic acid coating on the quality and microbial composition of fresh pompano (Trachinotus ovatus) fillets during ice storage for 24 days were evaluated. Samples were treated by distilled water (CK), ultrasound (US), chitosan grafted caffeic acid coating (G), and chitosan grafted caffeic acid coating with ultrasound-assisted (USG). Results showed that samples treated with USG could inhibit the formation of corrupt substances such as TVB-N, TBA, biogenic amines (BAs), hypoxanthine (Hx), and hypoxanthine riboside (HxR) when compared to the CK group.The results of high-throughput sequencing technology observed that the major bacteria genus of fresh samples was Acinetobacter.The diversity of bacterial communities at the initial stage was more diverse than that at the end of stage. With the extension of storage time, the USG treatment could maintain the microbial diversity. The dominant microbiota was Shewanella and Brochothrix in the CK group after 24 days of storage. In addition, Brochothrix in treated groups was effectively decreased. The microbial communities of samples in all treatments were changed during storage. At the end of storage, there was a significant difference in bacterial composition between the CK and treated samples, indicating that the treatment can effectively inhibit the growth of microorganisms, especially spoilage microorganisms, and reduce the quality deterioration caused by bacteria.
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Affiliation(s)
- Weiqing Lan
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; College of Food Science & Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Ocean University, Zhanjiang 524088, China; Shanghai Aquatic Products Processing and Storage Engineering Technology Research Center, Shanghai 201306, China; National Experimental Teaching Demonstration Center for Food Science and Engineering (Shanghai Ocean University), Shanghai 201306, China.
| | - Yuqing Sun
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
| | - Shucheng Liu
- College of Food Science & Technology, Guangdong Provincial Key Laboratory of Aquatic Product Processing and Safety, Guangdong Ocean University, Zhanjiang 524088, China.
| | - Yuan Guan
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
| | - Shengyun Zhu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
| | - Jing Xie
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China; Shanghai Aquatic Products Processing and Storage Engineering Technology Research Center, Shanghai 201306, China; National Experimental Teaching Demonstration Center for Food Science and Engineering (Shanghai Ocean University), Shanghai 201306, China.
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8
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Dai Y, Cui J, Gan P, Li W. Downregulation of tetrahydrobiopterin inhibits tumor angiogenesis in BALB/c-nu mice with hepatocellular carcinoma. Oncol Rep 2016; 36:669-75. [PMID: 27279530 PMCID: PMC4933545 DOI: 10.3892/or.2016.4850] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 12/04/2015] [Indexed: 02/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is a highly vascular tumor, and treatment options for patients of advanced-stage are limited. Nitric oxide (NO), which is derived from endothelial nitric oxide synthase (eNOS), provides crucial signals for angiogenesis in the tumor microenvironment. Tetrahydrobiopterin (BH4) is an essential cofactor eNOS and represents a critical determinant of NO production. To examine whether treatment of 2,4-diamino-6-hydroxypyrimidine (DAHP) inhibits angiogenesis of HCC, BALB/c-nu mice were injected with HepG-2 cells with DAHP. Supplemental DAHP treatment decreased K-ras mRNA transcripts, inhibition of phosphorylation of eNOS and Akt, inhibition of guanosine triphosphate cyclohydrolase (GTPCH), and decreased significantly NO synthesis, and then inhibited angiogenesis, compared with the results observed in the saline group. Histopathology demonstrated angiogenesis and tumor formation were significantly inhibited in HCC. DAHP downregulates GTPCH protein expression, corresponding to decreased levels of BH4 and the contents of NO. In addition, DAHP downregulates eNOS and Akt protein expression, corresponding to decreased eNOS phosphorylation at Ser1177 and Akt phosphorylation, compared with the saline control. We suggest that DAHP, recognized as a specific competitive inhibitor of GTPCH, can decrease tumor BH4 and NO by the inhibition of the wild-type Ras-PI3K/Akt pathway, and then inhibiting angiogenesis, and may provide a novel and promising way to target BH4 synthetic pathways to inhibit angiogenesis and to control potential progression of HCC. Whether DAHP has a therapeutic potential will require more direct testing in humans.
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Affiliation(s)
- Youguo Dai
- Department of Abdominal Surgery, Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118
| | | | - Ping Gan
- Department of Abdominal Surgery, Third Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650118
| | - Weiming Li
- Department of General Surgery, Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650101, P.R. China
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Wu HE, Baumgardt SL, Fang J, Paterson M, Liu Y, Du J, Shi Y, Qiao S, Bosnjak ZJ, Warltier DC, Kersten JR, Ge ZD. Cardiomyocyte GTP Cyclohydrolase 1 Protects the Heart Against Diabetic Cardiomyopathy. Sci Rep 2016; 6:27925. [PMID: 27295516 PMCID: PMC4904741 DOI: 10.1038/srep27925] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/26/2016] [Indexed: 02/06/2023] Open
Abstract
Diabetic cardiomyopathy increases the risk of heart failure and death. At present, there are no effective approaches to preventing its development in the clinic. Here we report that reduction of cardiac GTP cyclohydrolase 1 (GCH1) degradation by genetic and pharmacological approaches protects the heart against diabetic cardiomyopathy. Diabetic cardiomyopathy was induced in C57BL/6 wild-type mice and transgenic mice with cardiomyocyte-specific overexpression of GCH1 with streptozotocin, and control animals were given citrate buffer. We found that diabetes-induced degradation of cardiac GCH1 proteins contributed to adverse cardiac remodeling and dysfunction in C57BL/6 mice, concomitant with decreases in tetrahydrobiopterin, dimeric and phosphorylated neuronal nitric oxide synthase, sarcoplasmic reticulum Ca(2+) handling proteins, intracellular [Ca(2+)]i, and sarcoplasmic reticulum Ca(2+) content and increases in phosphorylated p-38 mitogen-activated protein kinase and superoxide production. Interestingly, GCH-1 overexpression abrogated these detrimental effects of diabetes. Furthermore, we found that MG 132, an inhibitor for 26S proteasome, preserved cardiac GCH1 proteins and ameliorated cardiac remodeling and dysfunction during diabetes. This study deepens our understanding of impaired cardiac function in diabetes, identifies GCH1 as a modulator of cardiac remodeling and function, and reveals a new therapeutic target for diabetic cardiomyopathy.
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Affiliation(s)
- Hsiang-En Wu
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
- National Institute on Drug Abuse, National Institutes of Health, 251 Bayview Boulevard, Baltimore, MA 21224, USA
| | - Shelley L. Baumgardt
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Juan Fang
- Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Mark Paterson
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Yanan Liu
- Department of Medicine, Columbia University, 630 W. 168th Street, New York, NY 10032, USA
| | - Jianhai Du
- Department of Biochemistry, University of Washington, 1705 NE Pacific Street, Seattle, WA 98195, USA
| | - Yang Shi
- Aurora Research Institute, Aurora Health Care, 750 W. Virginia Street, Milwaukee, WI 53234, USA
| | - Shigang Qiao
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Zeljko J. Bosnjak
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - David C. Warltier
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Judy R. Kersten
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Zhi-Dong Ge
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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Vančo J, Gáliková J, Hošek J, Dvořák Z, Paráková L, Trávníček Z. Gold(I) complexes of 9-deazahypoxanthine as selective antitumor and anti-inflammatory agents. PLoS One 2014; 9:e109901. [PMID: 25333949 PMCID: PMC4198181 DOI: 10.1371/journal.pone.0109901] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/10/2014] [Indexed: 01/06/2023] Open
Abstract
The gold(I) mixed-ligand complexes involving O-substituted derivatives of 9-deazahypoxanthine (HLn) and triphenylphosphine (PPh3) with the general formula [Au(Ln)(PPh3)] (1–5) were prepared and thoroughly characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopy, ESI+ mass spectrometry, single crystal X-ray (HL5 and complex 2) and TG/DTA analyses. Complexes 1–5 were evaluated for their in vitro antitumor activity against nine human cancer lines, i.e. MCF7 (breast carcinoma), HOS (osteosarcoma), A549 (adenocarcinoma), G361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) and THP-1 (monocytic leukaemia), for their in vitro anti-inflammatory activity using a model of LPS-activated macrophages, and for their in vivo antiedematous activity by λ-carrageenan-induced hind paw edema model on rats. The results showed that the complexes 1–5 exhibit selective in vitro cytotoxicity against MCF7, HOS, 22Rv1, A2780 and A2780R, with submicromolar IC50 values for 2 against the MCF7 (0.6 µM) and HOS (0.9 µM). The results of in vitro cytotoxicity screening on primary culture of human hepatocytes (HEP220) revealed up to 30-times lower toxicity of compounds against healthy cells as compared with cancer cells. Additionally, the complexes 1–5 significantly influence the secretion and expression of pro-inflammatory cytokines TNF-α and IL-1β by a similar manner as a commercially used anti-arthritic drug Auranofin. The tested complexes also significantly influence the rate and overall volume of the edema, caused by the intraplantar application of λ-carrageenan polysaccharide to rats. Based on these promising results, the presented compounds could qualify to become feasible candidates for advanced testing as potential antitumor and anti-inflammatory drug-like compounds.
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Affiliation(s)
- Ján Vančo
- Regional Centre of Advanced Technologies and Materials & Department of Inorganic Chemistry, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Jana Gáliková
- Regional Centre of Advanced Technologies and Materials & Department of Inorganic Chemistry, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Jan Hošek
- Regional Centre of Advanced Technologies and Materials & Department of Inorganic Chemistry, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Zdeněk Dvořák
- Regional Centre of Advanced Technologies and Materials & Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Olomouc, Czech Republic
| | - Lenka Paráková
- Department of Human Pharmacology and Toxicology, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences Brno, Brno, Czech Republic
| | - Zdeněk Trávníček
- Regional Centre of Advanced Technologies and Materials & Department of Inorganic Chemistry, Faculty of Science, Palacký University, Olomouc, Czech Republic
- * E-mail:
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Shanmuganathan MV, Krishnan S, Fu X, Prasadarao NV. Attenuation of biopterin synthesis prevents Escherichia coli K1 invasion of brain endothelial cells and the development of meningitis in newborn mice. J Infect Dis 2013; 207:61-71. [PMID: 23100563 PMCID: PMC3523800 DOI: 10.1093/infdis/jis656] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [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: 04/27/2012] [Accepted: 08/10/2012] [Indexed: 11/12/2022] Open
Abstract
Elevated levels of pterins and nitric oxide (NO) are observed in patients with septic shock and bacterial meningitis. We demonstrate that Escherichia coli K1 infection of human brain microvascular endothelial cells (HBMECs) induces the expression of guanosine triphosphate cyclohydrolase (GCH1), the rate-limiting enzyme in pterin synthesis, thereby elevating levels of biopterin. DAHP (2,4-diamino hydroxyl pyrimidine), a specific inhibitor of GCH1, prevented biopterin and NO production and invasion of E. coli K1 in HBMECs. GCH1 interaction with Ecgp96, the receptor for outer membrane protein A of E. coli K1, also increases on infection, and suppression of Ecgp96 expression prevents GCH1 activation and biopterin synthesis. Pretreatment of newborn mice with DAHP prevented the production of biopterin and the development of meningitis. These results suggest a novel role for biopterin synthesis in the pathogenesis of E. coli K1 meningitis.
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Affiliation(s)
| | | | - Xiaowei Fu
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, California
- Keck School of Medicine, University of Southern California, Los Angeles
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, Department of Pediatrics
- Department of Surgery
- Keck School of Medicine, University of Southern California, Los Angeles
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12
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Gangula PRR, Mukhopadhyay S, Ravella K, Cai S, Channon KM, Garfield RE, Pasricha PJ. Tetrahydrobiopterin (BH4), a cofactor for nNOS, restores gastric emptying and nNOS expression in female diabetic rats. Am J Physiol Gastrointest Liver Physiol 2010; 298:G692-9. [PMID: 20185690 PMCID: PMC2867432 DOI: 10.1152/ajpgi.00450.2009] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 02/18/2010] [Indexed: 01/31/2023]
Abstract
Gastroparesis is a debilitating disease predominantly affecting young women. Recently, dysregulation of neuronal nitric oxide synthase (nNOS) in myenteric plexus neurons has been implicated for delayed solid gastric emptying/gastroparesis in diabetic patients. In this study, we have explored the role of tetrahydrobiopterin (BH4), a major cofactor for nNOS activity and NO synthesis in diabetic gastroparesis. Diabetes was induced with single injection of streptozotocin (55 mg/kg body wt, ip) in female rats, with experiments performed on week 3 or 9 following induction, with or without 3-wk BH4 supplementation. Gastric pyloric BH4 levels were significantly decreased in diabetic female rats compared with control (18.6 +/- 1.45 vs. 31.0 +/- 2.31 pmol/mg protein). In vitro studies showed that 2,4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor of BH4 synthesis, significantly decreased gastric NO release and nitrergic relaxation. Three-week dietary supplementation of BH4 either from day 1 or week 6 significantly attenuated diabetes-induced delayed gastric emptying for solids (3 wk: BH4, 67 +/- 6.7 vs. diabetic, 36.05 +/- 7.09; 9 wk: BH4, 57 +/- 8.45 vs. diabetic, 33 +/- 9.91) and diabetes-induced reduction in pyloric nNOS-alpha protein expression in female rats. Supplementation of BH4 significantly restored gastric nNOS-alpha dimerization in 9-wk-old diabetic female rats. In addition, BH4 treatment reversed (17.23 +/- 5.81 vs. 42.0 +/- 2.70 mmHg x s) the diabetes-induced changes in intragastric pressures (IGP) and gastric pyloric nitrergic relaxation (-0.62 +/- 0.01 vs. -0.22 +/- 0.07). BH4 deficiency plays a critical role in diabetes-induced alterations including delayed solid gastric emptying, increased IGP, reduced pyloric nitrergic relaxation, and nNOS-alpha expression in female rats. Supplementation of BH4 accelerates gastric emptying by restoring nitrergic system in diabetic female rats. Therefore, BH4 supplementation is a potential therapeutic option for female patients of diabetic gastroparesis.
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Affiliation(s)
- Pandu R R Gangula
- Department of Obstetrics and Gynecology, Center for Women's Health Research, Meharry Medical College, Nashville, Tennessee 37208, USA.
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13
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An J, Du J, Wei N, Xu H, Pritchard KA, Shi Y. Role of tetrahydrobiopterin in resistance to myocardial ischemia in Brown Norway and Dahl S rats. Am J Physiol Heart Circ Physiol 2009; 297:H1783-91. [PMID: 19717731 PMCID: PMC2781371 DOI: 10.1152/ajpheart.00364.2009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 08/27/2009] [Indexed: 11/22/2022]
Abstract
Previously we showed that Brown Norway (BN/Mcw) rats are more resistant to myocardial ischemia-reperfusion (I/R) injury than Dahl S (SS/Mcw) rats due to increased nitric oxide (x NO) generation secondary to increased heat shock protein 90 (HSP90) association with endothelial nitric oxide synthase (NOS3). Here we determined whether increased resistance to I/R injury in BN/Mcw hearts is also related to tetrahydrobiopterin (BH(4)) and GTP cyclohydrolase I (GCH-1), the rate-limiting enzyme for BH(4) synthesis. We observed that BH(4) supplementation via sepiapterin (SP) and inhibition of GCH-1 via 2,4-diamino-6-hydroxypyrimidine (DAHP) differentially modulate cardioprotection and that SP alters the association of HSP90 with NOS3. BH(4) levels were significantly higher and 7,8-dihydrobiopterin (BH(2)) levels were significantly lower in BN/Mcw than in SS/Mcw hearts. The BH(4)-to-BH(2) ratio in BN/Mcw was more than two times that in SS/Mcw hearts. After I/R, BH(4) decreased and BH(2) increased in hearts from both strains compared with their preischemia levels. However, the increase in BH(2) in SS/Mcw hearts was significantly higher than in BN/Mcw hearts. Real-time PCR revealed that BN/Mcw hearts contained more GCH-1 transcripts than SS/Mcw hearts. SP increased recovery of left ventricular developed pressure (rLVDP) following I/R as well as decreased superoxide (O(2)(x-)) and increased x NO in SS/Mcw hearts but not in BN/Mcw hearts. DAHP decreased rLVDP as well as increased O(2)(x-) and decreased x NO in BN/Mcw hearts compared with controls but not in SS/Mcw hearts. SP increased the association of HSP90 with NOS3. These data indicate that BH(4) mediates resistance to I/R by acting as a cofactor and enhancing HSP90-NOS3 association.
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Affiliation(s)
- Jianzhong An
- Department of Pediatric Surgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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14
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Wang S, Xu J, Song P, Wu Y, Zhang J, Choi HC, Zou MH. Acute inhibition of guanosine triphosphate cyclohydrolase 1 uncouples endothelial nitric oxide synthase and elevates blood pressure. Hypertension 2008; 52:484-90. [PMID: 18645049 PMCID: PMC3523107 DOI: 10.1161/hypertensionaha.108.112094] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [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] [Indexed: 02/07/2023]
Abstract
GTP cyclohydrolase 1 (GTPCH1) is the rate-limiting enzyme in de novo synthesis of tetrahydrobiopterin (BH4), an essential cofactor for endothelial NO synthase (eNOS) dictating, at least partly, the balance of NO and superoxide produced by this enzyme. The aim of this study was to determine the effect of acute inhibition of GTPCH1 on BH4, eNOS function, and blood pressure (BP) in vivo. Exposure of bovine or mouse aortic endothelial cells to GTPCH1 inhibitors (2,4-diamino-6-hydroxypyrimidine or N-acetyl-serotonin) or GTPCH1 small-interference RNA (siRNA) significantly reduced BH4 and NO levels but increased superoxide levels. This increase was abolished by sepiapterin (BH4 precursor) or N(G)-nitro-L-arginine methyl ester (nonselective NOS inhibitor). Incubation of isolated murine aortas with 2,4-diamino-6-hydroxypyrimidine or N-acetyl-serotonin impaired acetylcholine-induced endothelium-dependent relaxation but not endothelium-independent relaxation. Aortas from GTPCH1 siRNA-injected mice, but not their control-siRNA injected counterparts, also exhibited impaired endothelium-dependent relaxation. BH4 reduction induced by GTPCH1 siRNA injection was associated with increased aortic levels of superoxide, 3-nitrotyrosine, and adhesion molecules (intercellular adhesion molecule 1 and vascular cell adhesion molecule 1), as well as a significantly elevated systolic, diastolic, and mean BP in C57BL6 mice. GTPCH1 siRNA was unable to elicit these effects in eNOS(-/-) mice. Sepiapterin supplementation, which had no effect on high BP in eNOS(-/-) mice, partially reversed GTPCH1 siRNA-induced elevation of BP in wild-type mice. In conclusion, GTPCH1 via BH4 maintains normal BP and endothelial function in vivo by preserving NO synthesis by eNOS.
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Affiliation(s)
- Shuangxi Wang
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jian Xu
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Ping Song
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Yong Wu
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Junhua Zhang
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Hyoung Chul Choi
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Ming-Hui Zou
- Division of Endocrinology and Diabetes, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Matei V, Rodríguez-Vilarrupla A, Deulofeu R, García-Calderó H, Fernández M, Bosch J, Garcia-Pagán JC. Three-day tetrahydrobiopterin therapy increases in vivo hepatic NOS activity and reduces portal pressure in CCl4 cirrhotic rats. J Hepatol 2008; 49:192-7. [PMID: 18534709 DOI: 10.1016/j.jhep.2008.04.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2007] [Revised: 04/04/2008] [Accepted: 04/04/2008] [Indexed: 02/08/2023]
Abstract
BACKGROUND/AIMS Tetrahydrobiopterin is an essential cofactor for NOS enzymes to synthesize NO. It has been suggested that reduced intrahepatic tetrahydrobiopterin decreases intrahepatic NO and contributes to increase hepatic vascular resistance and portal pressure in cirrhosis. The main aim of the study was to evaluate the effect of tetrahydrobiopterin supplementation in portal pressure in CCl4 cirrhotic rats. METHODS Cirrhotic rats received vehicle or tetrahydrobiopterin (10mg/kg/day i.p.) for 3 days. Hepatic and systemic hemodynamics and hepatic tetrahydrobiopterin, NOS activity and cGMP levels were measured. In addition, hepatic and systemic hemodynamics were evaluated in normal rats in which tetrahydrobiopterin deficiency was induced by administrating 2,4-diamino-6-hydroxy-pyrimidine (DAHP) for 8h. RESULTS In cirrhotic rats, tetrahydrobiopterin administration increased liver NOS activity and cGMP levels and markedly and significantly reduced portal pressure. Amelioration of portal hypertension was associated with a normalization of arterial pressure. In normal rats DAHP decreased hepatic tetrahydrobiopterin and NOS activity and increased hepatic vascular tone. These effects of DAHP administration were corrected by tetrahydrobiopterin supplementation. CONCLUSIONS The present study shows that tetrahydrobiopterin markedly reduces portal hypertension and improves systemic hemodynamics in cirrhotic rats. These data support the concept that tetrahydrobiopterin supplementation may represent a new therapeutic strategy for portal hypertension.
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Affiliation(s)
- Vasilica Matei
- Hepatic Hemodynamic Laboratory, Liver Unit, Institut de Malalties Digestives i Metabòliques, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Villarroel 170, 08036 Barcelona, Spain
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16
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Ikemoto K, Matsumoto T, Ohtsuki M, Itoh M, Tada S, Udagawa Y, Sumi-Ichinose C, Kondo K, Nomura T. 2,4-Diamino-6-hydroxypyrimidine (DAHP) suppresses cytokine-induced VCAM-1 expression on the cell surface of human umbilical vein endothelial cells in a BH(4)-independent manner. Biochim Biophys Acta 2008; 1780:960-5. [PMID: 18423409 DOI: 10.1016/j.bbagen.2008.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Revised: 03/19/2008] [Accepted: 03/20/2008] [Indexed: 12/01/2022]
Abstract
2,4-Diamino-6-hydroxypyrimidine (DAHP) is considered a specific inhibitor of BH(4) biosynthesis and is widely used in order to elucidate the possible biological function of BH(4) in various cells. In the present study, we found that both the synthesis of tetrahydrobiopterin (BH(4)) and expression of vascular cell adhesion molecule 1 (VCAM-1) were increased in human umbilical vein endothelial cells (HUVEC) treated with proinflammatory cytokines. Thus we examined the effects of DAHP to clarify whether BH(4) might be involved in the expression of VCAM-1 in HUVEC. DAHP reduced the levels of both BH(4) and VCAM-1 induced by TNF-alpha and IFN-gamma. However, the dose-response curves of DAHP for the suppression of the VCAM-1 level and that of BH(4) level were markedly different. Supplementation with sepiapterin failed to restore the depressed VCAM-1 level, although it completely restored the BH(4) level. Furthermore, DAHP significantly reduced the VCAM-1 level under the experimental conditions using TNF-alpha alone, which failed to induce BH(4) production. Taken together, these results indicate that DAHP inhibited the expression of VCAM-1 in a BH(4)-independent manner in HUVEC. In the present study, we also found that DAHP significantly suppressed the accumulation of cytokine-induced NF-kappaB (p65) in the nucleus as well as the mRNA levels of VCAM-1 and GTP cyclohydrolase I (GTPCH), the rate-limiting enzyme of BH(4) synthesis. The data obtained in this study suggest that DAHP reduced VCAM-1 and GTPCH protein synthesis at least partially via suppressing the NF-kappaB level in the nucleus of HUVEC.
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Affiliation(s)
- Kazuhisa Ikemoto
- Department of Pharmacology, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan
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Abstract
De novo purine biosynthesis has been studied in lymphocyte cell lines established from Lesch-Nyhan patients deficient in hypoxanthine-guanine phosphoribosyltransferase (HGPRT), in in vitro differentiating erythroleukaemic cell lines cloned from cells charactistic of virus-induced murine leukaemia, and in mutant hamster cells deficient in amidophosphoribosyltransferase. The relationship between cellular phosphoribosylpyrophosphate (PP-ribose-P) metabolism and the activity of the enzymes which catalyse the early steps of de novo purine biosynthesis has been explored. It was found that hamster cells deficient in amidophosphoribosyltransferase did not accumulate PP-ribose-P as do HGPRT-deficient cells. In these model systems, an accelerated rate of de novo purine biosynthesis tended to be associated with an increase in cellular PP-ribose-P cotent, but decreases in this rate results from the reduction in the activity of amidophosphoribosyltransferase. Regulation of ammonia-dependent de novo purine biosynthesis was similar to that of glutamine-dependent purine biosynthesis.
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Hamadate N, Noguchi K, Sakanashi M, Matsuzaki T, Nakasone J, Sakanashi M. Effect of decreased levels of intrinsic tetrahydrobiopterin on endothelial function in anesthetized rats. J Pharmacol Sci 2008; 107:49-56. [PMID: 18446004 DOI: 10.1254/jphs.fp0071967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Tetrahydrobiopterin (BH4) deficiency has been suggested to be an important factor in vascular endothelial dysfunction. In this study, we investigated the influence of decreased BH4 level produced by administration of 2,4-diamino-6-hydroxypyrimidine (DAHP), a specific inhibitor of the rate-limiting enzyme of BH4 synthesis, on vascular endothelial function in anesthetized rats. Wistar rats were given DAHP (0.1 - 1.0 g/kg, i.p.) or the vehicle 5 h before the experiment. Depressor responses to the endothelium-dependent vasodilator acetylcholine and the endothelium-independent vasodilator sodium nitroprusside were tested. After the experiment, blood and thoracic aorta were taken for estimating their BH4 levels and plasma concentrations of nitrite plus nitrate. DAHP produced marked decreases in BH4 levels in plasma and aorta in a dose-related manner. Baseline values for hemodynamics were not affected by DAHP. Depressor responses to acetylcholine were attenuated with the highest dose of DAHP (1.0 g/kg) but not with DAHP (0.3 g/kg), although similar decreases in BH4 levels were seen with these two doses of DAHP. Treatment with DAHP at each dose did not decrease plasma concentrations of nitrite plus nitrate. These findings suggest that a decrease in BH4 levels by acute inhibition of de novo BH4 synthesis does not necessarily cause endothelial dysfunction.
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Affiliation(s)
- Naobumi Hamadate
- Department of Pharmacology, School of Medicine, Faculty of Medicine, University of the Ryukyus, Japan
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19
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Wang JM, Wang Y, Huang JY, Yang Z, Chen L, Wang LC, Tang AL, Lou ZF, Tao J. C-Reactive protein-induced endothelial microparticle generation in HUVECs is related to BH4-dependent NO formation. J Vasc Res 2007; 44:241-8. [PMID: 17351328 DOI: 10.1159/000100558] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 12/25/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND C-reactive protein (CRP) has been proven to facilitate endothelial injury via reduced NO production. Endothelial microparticles (EMPs) have emerged as a novel marker of endothelial injury. METHODS In vitro cultured human umbilical vein endothelial cells (HUVECs) were incubated with CRP (20 mg/l) for 24 h. The numbers of EMPs with CD31- and CD51-positive staining were assessed flow-cytometrically, and NO production was measured using the Griess reaction in the presence or absence of tetrahydrobiopterin (BH(4)), respectively. RESULTS The number of EMPs was significantly increased in HUVECs stimulated by CRP compared with the control group and, in parallel, NO production was decreased (p < 0.05). In the presence of CRP, pretreatment with BH(4) decreased EMP counts and restored NO production to baseline levels (p < 0.05) while pretreatment with 2,4-diamino-6-hydroxypyrimidine (DAHP), a BH(4) synthesis inhibitor, further prompted EMP formation and decreased NO production (p < 0.05). However, adding exogenous BH(4) after pretreatment with DAHP suppressed EMP formation and restored NO production (p < 0.05). CONCLUSIONS This study demonstrates that CRP induces EMP generation in HUVECs and this effect is, at least in part, related to impaired BH(4)-dependent NO production. Augmented EMP generation in HUVECs is suggested as a novel potential mechanism contributing to the pathogenesis of vascular injury related to CRP.
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Affiliation(s)
- Jie-Mei Wang
- Department of Cardiology, First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China
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20
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Keough DT, Skinner-Adams T, Jones MK, Ng AL, Brereton IM, Guddat LW, de Jersey J. Lead compounds for antimalarial chemotherapy: purine base analogs discriminate between human and P. falciparum 6-oxopurine phosphoribosyltransferases. J Med Chem 2007; 49:7479-86. [PMID: 17149876 DOI: 10.1021/jm061012j] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The malarial parasite Plasmodium falciparum depends on the purine salvage enzyme hypoxanthine-guanine-xanthine phosphoribosyltransferase (HGXPRT) to convert purine bases from the host to nucleotides needed for DNA and RNA synthesis. An approach to developing antimalarial drugs is to use HGXPRT to convert introduced purine base analogs to nucleotides that are toxic to the parasite. This strategy requires that these compounds be good substrates for the parasite enzyme but poor substrates for the human counterpart, HGPRT. Bases with a chlorine atom in the 6-position or a nitrogen in the 8-position exhibited strong discrimination between P. falciparum HGXPRT and human HGPRT. The k(cat)/K(m) values for the Plasmodium enzyme using 6-chloroguanine and 8-azaguanine as substrates were 50 - 80-fold and 336-fold higher than for the human enzyme, respectively. These and other bases were effective in inhibiting the growth of the parasite in vitro, giving IC(50) values as low as 1 microM.
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Affiliation(s)
- Dianne T Keough
- School of Molecular and Microbial Sciences, The University of Queensland, 4072, Australia
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21
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Singh R, Fouladi-Nashta AA, Li D, Halliday N, Barrett DA, Sinclair KD. Methotrexate induced differentiation in colon cancer cells is primarily due to purine deprivation. J Cell Biochem 2006; 99:146-55. [PMID: 16598758 DOI: 10.1002/jcb.20908] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The folate antagonist methotrexate (MTX) inhibits synthesis of tetrahydrofolate (THF), pyrimidines and purines, and induces differentiation in several cell types. At 1 microM, MTX reduced proliferation and induced differentiation in HT29 colon cancer cells; the latter effect was augmented (P < 0.001) by thymidine (100 microM) but was reversed (P < 0.001) by the purines, hypoxanthine (Hx; 100 microM) and adenosine (100 microM). In contrast 5-fluoro-uracil (5-FU), a specific thymidylate synthase (TS) inhibitor, had no effect on differentiation, suggesting that MTX-induced differentiation is not due to a reduction in thymidine but to the inhibition of purine biosynthesis. Inhibition of cyclic AMP (cAMP) by RpcAMP (25 microM) further enhanced (P < 0.001) MTX induced differentiation, whereas the cAMP activator forskolin (10 microM) reversed (P < 0.001) MTX induced differentiation. These observations implicate a central role of adenosine and cAMP in MTX induced differentiation. By combining Western blot analysis with liquid chromatography-mass spectrometry (LC-MS)and HPLC analyses we also reveal both the expression and activity of key enzymes (i.e. methionine synthase (MS), s-adenosylhomocysteinase, cystathionine beta-synthase and ornithine decarboxylase) regulating methyl cycle, transsulfuration and polyamine pathways in HT29 colon cancer cells. At 1 microM, MTX induced differentiation was associated with a marked reduction in the intracellular concentrations of adenosine and, consequently, S-adenosylmethionine (SAM), S-adenosylhomocysteine, polyamines and glutathione (GSH). Importantly, the marked reduction in methionine that accompanied MS inhibition following MTX treatment was non-limiting with respect to SAM synthesis. Collectively, these findings indicate that the effects of MTX on cellular differentiation and single carbon metabolism are primarily due to the intracellular depletion of purines.
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Affiliation(s)
- R Singh
- School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, United Kingdom
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22
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Funderburk CD, Bowling KM, Xu D, Huang Z, O'Donnell JM. A typical N-terminal extensions confer novel regulatory properties on GTP cyclohydrolase isoforms in Drosophila melanogaster. J Biol Chem 2006; 281:33302-12. [PMID: 16966327 DOI: 10.1074/jbc.m602196200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [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: 11/06/2022] Open
Abstract
The cofactor tetrahydrobiopterin plays critical roles in the modulation of the signaling molecules dopamine, serotonin, and nitric oxide. Deficits in cofactor synthesis have been associated with several human hereditary diseases. Responsibility for the regulation of cofactor pools resides with the first enzyme in its biosynthetic pathway, GTP cyclohydrolase I. Because organisms must be able to rapidly respond to environmental and developmental cues to adjust output of these signaling molecules, complex regulatory mechanisms are vital for signal modulation. Mammalian GTP cyclohydrolase is subject to end-product inhibition via an associated regulatory protein and to positive regulation via phosphorylation, although target residues are unknown. GTP cyclohydrolase is composed of a highly conserved homodecameric catalytic core and non-conserved N-terminal domains proposed to be regulatory sites. We demonstrate for the first time in any organism that the N-terminal arms of the protein serve regulatory functions. We identify two different modes of regulation of the enzyme mediated through the N-terminal domains. The first is end-product feedback inhibition, catalytically similar to that of the mammalian enzyme, except that feedback inhibition by the cofactor requires sequences in the N-terminal arms rather than a separate regulatory protein. The second is a novel inhibitory interaction between the N-terminal arms and the active sites, which can be alleviated through the phosphorylation of serine residues within the N termini. Both mechanisms allow for acute and highly responsive regulation of cofactor production as required by downstream signaling pathways.
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Calcutt NA, Freshwater JD, Hauptmann N, Taylor EM, Mizisin AP. Protection of sensory function in diabetic rats by Neotrofin. Eur J Pharmacol 2006; 534:187-93. [PMID: 16507305 DOI: 10.1016/j.ejphar.2006.01.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [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] [Received: 08/11/2005] [Revised: 01/17/2006] [Accepted: 01/20/2006] [Indexed: 01/27/2023]
Abstract
We investigated the ability of Neotrofin, an agent that enhances endogenous nerve growth factor (NGF) levels, to prevent phenotypic, functional and structural changes that occur in the peripheral nerve of streptozotocin-diabetic rats. Eight weeks of Neotrofin treatment prevented depletion of NGF protein in plantar foot skin and sciatic nerve of diabetic rats and increased NGF protein in associated skeletal muscles. These effects were accompanied by maintenance of normal nerve levels of the neuropeptides substance P and calcitonin gene related peptide. Thermal hypoalgesia and conduction slowing of large sensory fibres in diabetic rats were ameliorated by Neotrofin treatment, whereas there was no effect on conduction slowing in large motor fibres or on reduced myelinated fibre axonal calibre. Enhancing endogenous production of neurotrophic factors using small molecules may be an alternative to either exogenous treatment with neurotrophic factors or gene therapy as a therapeutic approach to treating diabetic neuropathy.
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Affiliation(s)
- Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla 92093-0612, USA.
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24
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Hikishima S, Isobe M, Koyanagi S, Soeda S, Shimeno H, Shibuya S, Yokomatsu T. Synthesis and biological evaluation of 9-(5′,5′-difluoro-5′-phosphonopentyl)guanine derivatives for PNP-inhibitors. Bioorg Med Chem 2006; 14:1660-70. [PMID: 16263289 DOI: 10.1016/j.bmc.2005.10.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Accepted: 10/07/2005] [Indexed: 11/21/2022]
Abstract
9-(5',5'-Difluoro-5'-phosphonopentyl)guanine (DFPP-G) and its hypoxanthine analogue (DFPP-H) were modified by introducing a methyl group to all possible positions of the linker connecting a purine and difluoromethylenephosphonic acid moiety to evaluate the effects of the methyl group on inhibition against purine nucleoside phosphorylase. The methyl group on the linker affected the inhibition in a positional-dependent manner. Inhibitory potency of alpha-methyl and beta-methyl-substituted analogues of DFPP-H increased by about 600- to 1000-fold upon converting to cyclopropane nucleotide analogue (+/-)-4.
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Affiliation(s)
- Sadao Hikishima
- School of Pharmacy, Tokyo University of Pharmacy and Life Science, Japan
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25
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Ewing JF, Maines MD. Regulation and expression of heme oxygenase enzymes in aged-rat brain: age related depression in HO-1 and HO-2 expression and altered stress-response. J Neural Transm (Vienna) 2006; 113:439-54. [PMID: 16467964 DOI: 10.1007/s00702-005-0408-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [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] [Received: 06/06/2005] [Accepted: 09/26/2005] [Indexed: 10/25/2022]
Abstract
The heme oxygenase isozymes, HO-1 and HO-2, oxidatively cleave the heme molecule to produce biliverdin and the gaseous messenger, CO. The cleavage results in the release of iron, a regulator of transferrin, ferritin, and nitric oxide (NO) synthase gene expression. Biliverdin reductase (BVR) then catalyzes the reduction of biliverdin, generating the potent intracellular antioxidant, bilirubin. We report an age-related decrease in HO-1 and HO-2 expression present in select brain regions including the hippocampus and the substantia nigra, that are involved in the high order cognitive processes of learning and memory. The age-related loss of monoxide-producing potential in select regions of the brain was not specific to the HO system but was also observed in neuronal NO-generating system. Furthermore, compared to 2-month old rats, the ability of aged brain tissue to respond to hypoxic/hyperthermia was compromised at both the protein and the transcription levels as judged by attenuated induction of HO-1 immunoreactive protein and its 1.8 Kb transcript. Neotrofin (AIT), a cognitive-enhancing and neuroprotective drug, caused a robust increase in HO-1 immunoreactive protein in select neuronal regions and increased the expression of HO-2 transcripts. The potential interplay between regulation of HO-2 gene expression and the serum levels of the adrenal steroids is discussed. We suggest the search for therapeutic agents that reverse the decline and aberrant stress response of HO enzymes may lead to effective treatment regimens for age-associated neuronal deficits.
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Affiliation(s)
- J F Ewing
- Department of Biochemistry/Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
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26
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Kamada Y, Jenkins GJ, Lau M, Dunbar AY, Lowe ER, Osawa Y. Tetrahydrobiopterin depletion and ubiquitylation of neuronal nitric oxide synthase. Brain Res Mol Brain Res 2005; 142:19-27. [PMID: 16216381 DOI: 10.1016/j.molbrainres.2005.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2005] [Revised: 08/23/2005] [Accepted: 09/05/2005] [Indexed: 11/18/2022]
Abstract
Tetrahydrobiopterin is a necessary cofactor for the synthesis of nitric oxide by the hemeprotein enzyme, NO-synthase (NOS). It is widely thought that inadequate levels of tetrahydrobiopterin lead to tissue injury and organ dysfunction due, in part, to formation of superoxide from pterin-deficient NOS. In the course of studies on the ubiquitylation of neuronal NOS (nNOS), we have found that certain substrate analogs, such as N(G)-nitro-L-arginine, stabilize the dimeric form of nNOS and protect the enzyme from ubiquitylation. Since tetrahydrobiopterin is known to bind near heme and confers stability to the active dimeric structure of nNOS, we wondered if the loss of tetrahydrobiopterin could be an endogenous signal for nNOS ubiquitylation and degradation. We show here in HEK293 cells stably transfected with nNOS that depletion of tetrahydrobiopterin by treatment with 2,4-diamino-6-hydroxypyrimidine leads to destabilization of the dimeric form and enhances ubiquitylation of nNOS. Sepiapterin, a precursor to tetrahydrobiopterin in the salvage pathway, completely reverses the effect of 2,4-diamino-6-hydroxypyrimidine on nNOS ubiquitylation. Consistent with that found in cells, the in vitro ubiquitylation of nNOS by reticulocyte proteins decreases when tetrahydrobiopterin is present. Thus, inadequate amounts of tetrahydrobiopterin may lead to a sustained decrease in the steady state level of nNOS that is not readily reversed.
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Affiliation(s)
- Yasuhiko Kamada
- Department of Pharmacology, The University of Michigan Medical School, 1301 Medical Science Research Building III, Ann Arbor, MI 48109-0632, USA
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27
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Kidd GA, Hong H, Majid A, Kaufman DI, Chen AF. Inhibition of brain GTP cyclohydrolase I and tetrahydrobiopterin attenuates cerebral infarction via reducing inducible NO synthase and peroxynitrite in ischemic stroke. Stroke 2005; 36:2705-11. [PMID: 16282548 DOI: 10.1161/01.str.0000190000.98707.6d] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Inducible NO synthase (NOS)-derived peroxynitrite (ONOO-) during ischemia/reperfusion contributes to ischemic brain injury. However, inducible NOS (iNOS) regulation in ischemic stroke remains unknown. Tetrahydrobiopterin (BH4) is an essential cofactor for NOS activity. The present study tested the hypothesis that inhibition of endogenous BH4 rate-limiting enzyme GTP cyclohydrolase I (GTPCH I), and thus BH4 synthesis, reduces cerebral infarction via inhibiting iNOS and ONOO- in transient focal ischemia. METHODS Focal ischemia (2 hours) was created in adult male Sprague-Dawley rats (250 to 300 g) by middle cerebral artery occlusion (MCAO). Rats were treated 12 hours before MCAO with vehicle or diamino-6-hydroxypyrimidine (DAHP; 0.5 g/kg IP), a selective GTPCH I inhibitor. Brains were harvested 24 hours after reperfusion for assays of infarct volume, blood-brain barrier (BBB) permeability, GTPCH I activity, BH4 levels, GTPCH I and NOS mRNA, protein expression, and superoxide anion (O2*-) and ONOO- levels. RESULTS Endogenous GTPCH I activity, BH4 levels, iNOS activity, and (O2*- and ONOO- levels were all augmented after ischemia/reperfusion. DAHP treatment significantly reduced GTPCH I activity, resulting in decreased BH4 levels, iNOS activity, and ONOO- levels. Consequently, DAHP treatment significantly reduced the infarct size compared with the nontreated group (22.3+/-5.6 versus 38.3+/-7.4%; n=6; P<0.05). Similarly, BBB permeability was significantly reduced after DAHP pretreatment compared with the control group (4.11+/-0.22 versus 7.78+/-0.44 microg/g tissue; n=5; P<0.05). CONCLUSIONS These results demonstrate that blockade of endogenous brain BH4 synthesis attenuates cerebral infarction via inhibiting iNOS and ONOO-, which may provide a mechanistic basis of novel therapeutic strategies for ischemic stroke.
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Affiliation(s)
- Grant A Kidd
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824-1317, USA
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Kim ST, Choi JH, Chang JW, Kim SW, Hwang O. Immobilization stress causes increases in tetrahydrobiopterin, dopamine, and neuromelanin and oxidative damage in the nigrostriatal system. J Neurochem 2005; 95:89-98. [PMID: 16181415 DOI: 10.1111/j.1471-4159.2005.03342.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Oxidative stress is believed to contribute to the pathophysiology of Parkinson's disease, in which nigrostriatal dopaminergic (DA) neurons undergo degeneration. Identification of endogenous molecules that contribute to generation of oxidative stress and vulnerability of these cells is critical in understanding the etiology of this disease. Exposure to tetrahydrobiopterin (BH4), the obligatory cofactor for DA synthesis, was observed previously to cause oxidative damage in DA cells. To demonstrate the physiological relevance of this observation, we investigated whether an overproduction of BH4 and DA might actually occur in vivo, and, if it did, whether this might lead to oxidative damage to the nigrostriatal system. Immobilization stress (IMO) elevated BH4 and DA and their synthesizing enzymes, tyrosine hydroxylase and GTP cyclohydrolase I. This was accompanied by elevation of lipid peroxidation and protein-bound quinone, and activities of antioxidant enzymes. These increases in the indices of oxidative stress appeared to be due to increased BH4 synthesis because they were abolished following administration of the BH4 synthesis inhibitor, 2,4-diamino-6-hydroxy-pyrimidine. IMO also caused accumulation of neuromelanin and degeneration of the nigrostriatal system. These results demonstrate that a severe stress can increase BH4 and DA and cause oxidative damages to the DA neurons in vivo, suggesting relevance to Parkinson's disease.
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Affiliation(s)
- Sung Tae Kim
- Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul, Korea
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Abstract
BACKGROUND AND PURPOSE Purinergic nucleoside inosine elicits protection and regeneration during various injuries. The purpose of this study was to examine the protective effects of inosine against cerebral ischemia. METHODS Adult Sprague-Dawley rats were anesthetized. Inosine, hypoxathine, or vehicle was administered intracerebroventricularly before transient right middle cerebral artery occlusion (MCAo). Animals were placed in behavioral chambers 2 days to 2 weeks after MCAo and then euthanized for tri-phenyl-tetrazolium chloride staining. Glutamate release was measured by microdialysis/high-performance liquid chromatography, and single-unit action potentials were recorded from neurons in the parietal cortex. RESULTS Stroke animals receiving inosine pretreatment demonstrated a higher level of locomotor activity and less cerebral infarction. Intracerebroventricular administration of the same dose of hypoxanthine did not confer protection. Coadministration of selective A3 receptor antagonist 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1, 4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS1191) significantly reduced inosine-mediated protection. Inosine did not alter basal glutamate release, nor did it reduce ischemia-evoked glutamate overflow from cerebral cortex. However, inosine antagonized glutamate-induced electrophysiological excitation in cerebral cortical neurons. CONCLUSIONS Inosine inhibits glutamate postsynaptic responses and reduces cerebral infarction. Its protective effect against ischemia/reperfusion-related insults may involve activation of adenosine A3 receptors.
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Affiliation(s)
- Hui Shen
- National Institute on Drug Abuse, National Institutes of Health, Baltimore, Md, USA
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Abstract
Inhibition of GTP cyclohydrolase I (GTPCH) has been used as a selective tool to assess the role of de novo synthesis of (6R)-5,6,7,8-tetrahydro-L-biopterin (BH4) in a biological system. Toward this end, 2,4-diamino-6-hydroxypyrimidine (DAHP) has been used as the prototypical GTPCH inhibitor. Using a novel real-time kinetic microplate assay for GTPCH activity and purified prokaryote-expressed recombinant proteins, we show that potent inhibition by DAHP is not the result of a direct interaction with GTPCH. Rather, inhibition by DAHP in phosphate buffer occurs via an indirect mechanism that requires the presence of GTPCH feedback regulatory protein (GFRP). Notably, GFRP was previously discovered as the essential factor that reconstitutes inhibition of pure recombinant GTPCH by the pathway end product BH4. Thus, DAHP inhibits GTPCH by engaging the endogenous feedback inhibitory system. We further demonstrate that L-Phe fully reverses the inhibition of GTPCH by DAHP/GFRP, which is also a feature in common with inhibition by BH4/GFRP. These findings suggest that DAHP is not an indiscriminate inhibitor of GTPCH in biological systems; instead, it is predicted to preferentially attenuate GTPCH activity in cells that most abundantly express GFRP and/or contain the lowest levels of L-Phe.
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Affiliation(s)
- Monica A Kolinsky
- Department of Pharmacology, Weill Medical College of Cornell University, New York, New York 10021, USA
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31
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He A, Rosazza JPN. GTP cyclohydrolase I: purification, characterization, and effects of inhibition on nitric oxide synthase in nocardia species. Appl Environ Microbiol 2003; 69:7507-13. [PMID: 14660404 PMCID: PMC309945 DOI: 10.1128/aem.69.12.7507-7513.2003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2003] [Accepted: 09/04/2003] [Indexed: 11/20/2022] Open
Abstract
GTP cyclohydrolase I (GTPCH) catalyzes the first step in pteridine biosynthesis in Nocardia sp. strain NRRL 5646. This enzyme is important in the biosynthesis of tetrahydrobiopterin (BH4), a reducing cofactor required for nitric oxide synthase (NOS) and other enzyme systems in this organism. GTPCH was purified more than 5,000-fold to apparent homogeneity by a combination of ammonium sulfate fractionation, GTP-agarose, DEAE Sepharose, and Ultragel AcA 34 chromatography. The purified enzyme gave a single band for a protein estimated to be 32 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular mass of the native enzyme was estimated to be 253 kDa by gel filtration, indicating that the active enzyme is a homo-octamer. The enzyme follows Michaelis-Menten kinetics, with a Km for GTP of 6.5 micromoles. Nocardia GTPCH possessed a unique N-terminal amino acid sequence. The pH and temperature optima for the enzyme were 7.8 and 56 degrees C, respectively. The enzyme was heat stable and slightly activated by potassium ion but was inhibited by calcium, copper, zinc, and mercury, but not magnesium. BH4 inhibited enzyme activity by 25% at a concentration of 100 micromoles. 2,4-Diamino-6-hydroxypyrimidine (DAHP) appeared to competitively inhibit the enzyme, with a Ki of 0.23 mM. With Nocardia cultures, DAHP decreased medium levels of NO2- plus NO3-. Results suggest that in Nocardia cells, NOS synthesis of nitric oxide is indirectly decreased by reducing the biosynthesis of an essential reducing cofactor, BH4.
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Affiliation(s)
- Aimin He
- Division of Medicinal and Natural Products Chemistry and Center for Biocatalysis and Bioprocessing, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242, USA
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32
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Saint-Dic D, DuBow MS. Effect of cis-located human satellite DNA on electroporation efficiency. Methods Mol Biol 2003; 48:199-210. [PMID: 8528392 DOI: 10.1385/0-89603-304-x:199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- D Saint-Dic
- Department of Microbiology and Immunology, McGill University, Montreal, Canada
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Abstract
GTP cyclohydrolase 1 is the rate-limiting enzyme in production of tetrahydrobiopterin, a necessary cofactor for endothelial nitric oxide synthase. We tested the hypothesis that inhibition of tetrahydrobiopterin synthesis impairs endothelium-dependent relaxation and increase blood pressure in rats. 2,4-Diamino-6-hydroxypyrimidine (DAHP), a GTP cyclohydrolase 1 inhibitor, was given in drinking water (approximately 120 mg.kg(-1).day(-1)) to male Sprague-Dawley rats for 3 days. Systolic blood pressures were measured (tail-cuff procedure) for 3 days before and each day during DAHP treatment. Blood pressure was significantly increased after DAHP treatment (122 +/- 2 vs. 154 +/- 3 mmHg before and after DAHP, respectively; P < 0.05). Endothelium-intact aortic segments from pentobarbital sodium-anesthetized rats were isolated and hung in organ chambers for measurement of isometric force generation. Aortas from DAHP-treated rats exhibited a decreased maximal relaxation to ACh compared with controls [% relaxation from phenylephrine (10-7 M)-induced contraction: DAHP 57 +/- 6% vs. control 79 +/- 4%; P < 0.05]. Relaxation responses to A-23187 were also decreased in aortas from DAHP-treated rats compared with controls. Incubation with sepiapterin (10-4 M, 1 h), which produces tetrahydrobiopterin via a salvage pathway, restored relaxation to ACh in aortas from DAHP-treated rats. Superoxide dismutase significantly increased ACh-induced relaxation in aortas from DAHP-treated rats, whereas catalase had no effect. Endothelium-independent relaxation to sodium nitroprusside in aortas from DAHP-treated rats was not different from control rats; however, nitric oxide synthase inhibition increased sensitivity to sodium nitroprusside in aortas from DAHP-treated rats. These results support the hypothesis that GTP cyclohydrolase 1 inhibition decreases relaxation and increases blood pressure in rats.
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Affiliation(s)
- Brett M Mitchell
- Department of Physiology CL-3162, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912, USA.
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Nair RR, Preeta R, Smitha G, Adiga I. Variation in mitogenic response of cardiac and pulmonary fibroblasts to cerium. Biol Trace Elem Res 2003; 94:237-46. [PMID: 12972691 DOI: 10.1385/bter:94:3:237] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2002] [Accepted: 02/01/2003] [Indexed: 11/11/2022]
Abstract
Fibroproliferative response of rat heart and lung fibroblasts to the lanthanide cerium was examined, as the element has been implicated in the causation of cardiac and pulmonary fibrosis. Fibroblasts from both of the organs were morphologically identical, and the response to fetal bovine serum, a nonspecific mitogen, was also comparable. The oxygen radical generator (hypoxanthine + xanthine oxidase [Hyp. + XO]) induced a proliferative response that was neutralized in both cardiac and lung fibroblasts by free-radical scavengers. Superoxide dismutase was more effective than catalase in reducing the mitogenic effect of Hyp. + XO. The free-radical scavenger N-acetyl-L-cysteine neutralized the free-radical-mediated changes in pulmonary fibroblasts but had a negative effect in cardiac fibroblasts, indicating a tissue-dependent variation. Reactive oxygen species are known to act as biological mediators of tissue fibrosis induced by metallic compounds. Exposure to low levels of cerium (0.5 microM) stimulated a mitogenic response in cardiac fibroblasts, but the pulmonary fibroblasts were not sensitized by the element. Tissue-dependent variation in proliferative response to cerium shows a positive association with intracellular generation of reactive oxygen species. Fibrotic changes in cerium pneumoconiosis may either be replacement fibrosis following tissue damage or mediated by nonfibroblastic cells. The study confirms that cardiac and pulmonary fibroblasts are dissimilar cellular subtypes.
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Affiliation(s)
- Renuka R Nair
- Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala - 695 011, India
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Madsen JT, Jansen P, Hesslinger C, Meyer M, Zimmer J, Gramsbergen JB. Tetrahydrobiopterin precursor sepiapterin provides protection against neurotoxicity of 1-methyl-4-phenylpyridinium in nigral slice cultures. J Neurochem 2003; 85:214-23. [PMID: 12641743 DOI: 10.1046/j.1471-4159.2003.01666.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Complex-I inhibition and oxidative processes have been implicated in the loss of nigral dopamine neurones in Parkinson's disease and the toxicity of MPTP and its metabolite MPP+. Tetrahydrobiopterin, an essential cofactor for tyrosine hydroxylase, may act as an antioxidant in dopaminergic neurones and protects against the toxic consequences of glutathione depletion. Here we studied the effects of manipulating tetrahydrobiopterin levels on MPP+ toxicity in organotypic, rat ventral mesencephalic slice cultures. In cultures exposed to 30 micro m MPP+ for 2 days, followed by 8 days 'recovery' in control medium, we measured dopamine and its metabolites in the tissue and culture medium by HPLC, lactate dehydrogenase release to the culture medium, cellular uptake of propidium iodide and counted the tyrosine hydroxylase-immunoreactive neurones. Inhibition of tetrahydrobiopterin synthesis by 2,4-diamino-6-hydroxypyrimidine had no significant synergistic effect on MPP+ toxicity. In contrast, the tetrahydrobiopterin precursor l-sepiapterin attenuated the MPP+-induced dopamine depletion and loss of tyrosine hydroxylase-positive cells in a dose-dependent manner with 40 micro m l-sepiapterin providing maximal protection. Accordingly, increasing intracellular tetrahydrobiopterin levels may protect against oxidative stress by complex-I inhibition.
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Affiliation(s)
- Jakob Torp Madsen
- Anatomy and Neurobiology, Institute of Medical Biology, University of Southern Denmark, Odense, Denmark
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Yamashiro S, Noguchi K, Kuniyoshi Y, Koja K, Sakanashi M. Role of tetrahydrobiopterin on ischemia-reperfusion injury in isolated perfused rat hearts. J Cardiovasc Surg (Torino) 2003; 44:37-49. [PMID: 12627070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
AIM It has recently been shown that nitric oxide synthase in the presence of suboptimal levels of tetrahydrobiopterin (BH(4)), an essential cofactor of nitric oxide synthase, may favor increased production of oxygen free radicals. This study was designed to define the role of BH(4) in myocardial ischemia-reperfusion injury. METHODS Isolated perfused rat hearts were subjected to 37 degrees C ischemia and reperfusion. Hearts were received with BH(4) or vehicle for 5 min just before ischemia and during the first 5 min of the reperfusion period. The effects of BH(4) on left ventricular function, myocardial contents of lipid peroxidation and high energy phosphates, and levels of lactate dehydrogenase and nitrite plus nitrate in perfusate before ischemia and after reperfusion were estimated. Moreover, the effect of BH(4) given with 2,4-diamino-6-hydroxypyrimidine (DAHP), a selective inhibitor of BH(4) production, intraperitoneally 24 h before the experiments were estimated. RESULTS BH(4) improved contractile and metabolic abnormalities in reperfused hearts. Furthermore, BH(4) significantly alleviated ischemic contracture during ischemia, and restored diminished perfusate levels of nitrite plus nitrate after reperfusion. On the other hand, DAHP-treatment aggravated ischemia-reperfusion induced functional and metabolic abnormalities. Administration of BH(4) improved DAHP-induced functional and metabolic abnormalities. CONCLUSION Results demonstrated that BH(4) lessens ischemia-reperfusion injury in isolated perfused rat hearts. Conversely, deficiency of BH(4) seems to accelerate endothelial dysfunction and myocardial ischemia-reperfusion injury. Present data may be compatible with the hypothesis that nitric oxide synthase in the presence of insufficiency of BH(4) serve as the cause of oxidative injury.
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Affiliation(s)
- S Yamashiro
- 2ndDepartment of Surgery, School of Medicine, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
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Kawahara K, Takase M, Yamauchi Y. Increased vulnerability to ischemia/reperfusion-induced ventricular tachyarrhythmias by pre-ischemic inhibition of nitric oxide synthase in isolated rat hearts. Cardiovasc Pathol 2003; 12:49-56. [PMID: 12598018 DOI: 10.1016/s1054-8807(02)00155-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
INTRODUCTION The relationship between vulnerability to reperfusion-induced ventricular tachyarrhythmias, such as ventricular tachycardia (VT) and fibrillation (VF), and the endogenous activity of nitric oxide synthase (NOS) has not been well documented. The objective of the present study was to clarify whether the vulnerability to reperfusion-induced VT/VF changes with preishemic, sustained inhibition of NOS. METHODS The experiments were performed using Langendorff-perfused isolated rat hearts, in which left ventricular pressure (LVP) and left ventricular cardiomyograms (LVCMGs) were measured. RESULTS A pre-ischemic, sustained inhibition of NOS resulted in an increased vulnerability to reperfusion-induced VT/VF, and the increase was markedly attenuated by co-treatment with L-arginine or by post-ischemic treatment with 2,4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor of tetrahydrobiopterin (BH(4)) synthesis. We then tried to elucidate whether nitric oxide (NO) and superoxide were produced during reperfusion, and ATP-sensitive potassium channels (K(ATP)), especially mitochondrial ATP-sensitive potassium channels (mitoK(ATP)), are involved in the increased vulnerability. Post-ischemic inhibition of NOS and treatment with a NO scavenger attenuated the increased vulnerability to reperfusion-induced VT/VF, but post-ischemic treatment with a superoxide scavenger did not. In addition, post-ischemic treatment with S-nitroso-N-acetyl-DL-penicillamine (SNAP), a NO donor, or with diazoxide, a selective opener of mitoK(ATP), increased the VT/VF duration during reperfusion. The increased vulnerability to VT/VF was attenuated by the treatment with a selective mitoK(ATP) blocker. CONCLUSION The results suggest that a pre-ischemic, sustained inhibition of NOS increases the vulnerability to reperfusion-induced VT/VF, and the NO-mitoK(ATP) pathway is one of the possible factors contributing to the increased vulnerability to VT/VF.
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Affiliation(s)
- Koichi Kawahara
- Laboratory of Biomedical Control, Research Institute for Electronic Science, Hokkaido University, 060-0812, Sapporo, Japan.
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Bagi Z, Koller A. Lack of nitric oxide mediation of flow-dependent arteriolar dilation in type I diabetes is restored by sepiapterin. J Vasc Res 2003; 40:47-57. [PMID: 12644725 DOI: 10.1159/000068938] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [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] [Received: 05/02/2002] [Accepted: 10/10/2002] [Indexed: 11/19/2022] Open
Abstract
The mechanisms leading to microangiopathy in diabetes mellitus have still not been clearly elucidated. We hypothesized that type I diabetes mellitus affects the endothelium and alters flow-dependent dilation of arterioles, an important mechanism involved in local regulation of blood flow. Isolated, pressurized gracilis muscle arterioles (inside diameter approximately 150 microm at 80 mm Hg) from rats with streptozotocin (STZ)-induced diabetes mellitus exhibited reduced dilations induced by increases in perfusate flow compared to those of normal rats (plasma glucose: 25.7 +/- 0.7 vs. 6.4 +/- 0.5 mmol/l; maximum increase in diameter: 15 +/- 4 vs. 31+/- 3 microm, p < 0.05). In control arterioles, both nitric oxide (NO) and prostaglandins mediated the flow-dependent dilation, whereas flow-induced dilations of diabetic arterioles were unaffected by N(omega)-nitro-L-arginine methyl ester (L-NAME) and were abolished by indomethacin. Sepiapterin - precursor of the endothelial NO synthase (eNOS) cofactor tetrahydrobiopterin (BH(4)) - restored the L-NAME-sensitive portion of flow-dependent dilations of diabetic arterioles. Furthermore, depletion of BH(4) by 2,4-diamino-6-hydroxypyrimidine (DAHP) in control arterioles also resulted in reduced flow-dependent dilations, which were restored by intraluminal sepiapterin [but not with superoxide dismutase (SOD) plus catalase (CAT) (SOD+CAT)] and then could be inhibited by L-NAME. Dilations induced by the NO donor sodium nitroprusside (SNP) were unaffected by L-NAME in diabetes mellitus arterioles or when eNOS was activated by intraluminal flow in DAHP-treated arterioles (with or without SOD+CAT). In contrast, pyrogallol (known to produce reactive oxygen species) substantially reduced acetylcholine- and SNP-induced dilation in a SOD+CAT-reversible manner. Collectively, these findings suggest that in diabetic arterioles, due to the reduced bioavailability of BH(4), the synthesis of NO by eNOS is limited, resulting in a reduced flow-induced dilation, a mechanism that may also be responsible for the development of diabetic microangiopathy and exacerbation of other vascular diseases.
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Affiliation(s)
- Zsolt Bagi
- Department of Pathophysiology, Semmelweis University, Budapest, Hungary
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Abstract
OBJECTIVE Guanosine triphosphate-cyclohydrolase I (GTP-CHI) is the first and rate-limiting enzyme for the de novo biosynthesis of biopterin. The objective of present study was to observe the effect of 2,4-diamino-6-hydroxy-pyrimidine (DAHP), an inhibitor of GTP-CHI, on the development of postburn Staphylococcus aureus sepsis. DESIGN A prospective, controlled animal study. SETTING A research laboratory in a hospital. SUBJECTS Male Wistar rats. INTERVENTIONS Fifty-six male Wistar rats were randomly divided into four groups as follows: normal control group (n = 10), scald control group (n = 10), postburn sepsis group (n = 20), and DAHP treatment group (n = 16). In the scald control group, rats were subjected to a 20% total body surface area third-degree scald injury and then were killed at 24 hrs. In the postburn sepsis group (n = 20), rats were inflicted with 20% total body surface area third-degree scald followed by Staphylococcus aureus challenge, and they were further divided into 2- and 6-hr groups. In the DAHP treatment group (n = 16), animals were intraperitoneally injected with a dose of 1 g/kg DAHP before Staphylococcus aureus challenge and then were further divided into 2- and 6-hr groups. Tissue samples from liver, kidneys, lungs, and heart were collected to determine GTP-CHI, inducible nitric oxide synthase, and tumor necrosis factor-alpha messenger RNA expression. Meanwhile, biopterin and nitric oxide concentrations in these tissues were also measured. MEASUREMENTS AND MAIN RESULTS After the scald injury followed by Staphylococcus aureus challenge, GTP-CHI messenger RNA expression and biopterin concentrations were significantly elevated in various tissues such as liver, heart, kidneys, and lungs, as were the values of inducible nitric oxide synthase messenger RNA expression and nitric oxide formation (p <.01). Pretreatment with DAHP significantly reduced GTP-CHI/biopterin induction (p <.05-.01), and the up-regulation of inducible nitric oxide synthase/nitric oxide was also suppressed. Furthermore, DAHP administration inhibited the gene expression of tumor necrosis factor-alpha. Two hours after septic challenge, tumor necrosis factor-alpha messenger RNA expression in liver, kidneys, and lungs in the DAHP-treated group was 35.7%, 37.3%, and 33.0% of that in the postburn septic group, respectively. Additionally, in animals without DAHP treatment, the 6-hr mortality rate was 55.6% (20 of 36), whereas it was only 25.0% in DAHP-treated animals (4 of 16, p =.08). CONCLUSIONS Early treatment with DAHP might be a potential strategy to prevent the development of postburn Staphylococcal sepsis, which appears to be associated with down-regulation of biopterin and nitric oxide formation by DAHP.
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Affiliation(s)
- Hong-Yun Li
- Department of Microbiology and Immunology, Trauma Research Center, Postgraduate Medical College, 304th Hospital, Beijing, People's Republic of China
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Abstract
Tetrahydrobiopterin (BH4) is an essential co-factor for nitric oxide synthases (NOS). The aim of the present work was to study whether BH4 deficiency affects the vulnerability of neurones in primary culture to hypoxia. Intracellular BH4 levels were depleted by pre-incubating neurones with 5 mm 2,4-diamino-6-hydroxypyrimidine (DAHP) for 18 h, after which cells were exposed for 1 h to normoxic or hypoxic conditions. Our results showed that whereas neurones were resistant to hypoxia-induced cellular damage, BH4 deficiency in neurones led to oxidative stress, mitochondrial depolarization, ATP depletion and necrosis after 1 h of hypoxia. Indeed, hypoxia specifically inhibited mitochondrial complex IV activity in BH4-deficient neurones. All these effects were counteracted when neuronal BH4 levels were restored by incubating cells with exogenous BH4 during the hypoxic period. Moreover, hypoxia-induced damage in BH4-deficient neurones was prevented when Nomega-nitro-l-arginine monomethyl ester (NAME), haemoglobin or superoxide dismutase plus catalase were present during the hypoxic period, suggesting that peroxynitrite might be involved in the process. In fact, BH4 deficiency elicited neuronal NO dysfunction, resulting in an increase in peroxynitrite generation by cells, as shown by the enhancement in tyrosine nitration; this was prevented by supplements of BH4, NAME, haemoglobin or superoxide dismutase plus catalase during hypoxia. Our results suggest that BH4 deficiency converts neuronal NOS into an efficient peroxynitrite synthase, which is responsible for the increase in neuronal vulnerability to hypoxia-induced mitochondrial damage and necrosis.
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Tanaka J, Koshimura K, Murakami Y, Kato Y. Possible involvement of tetrahydrobiopterin in the trophic effect of insulin-like growth factor-1 on rat pheochromocytoma-12 (PC12) cells. Neurosci Lett 2002; 328:201-3. [PMID: 12133588 DOI: 10.1016/s0304-3940(02)00497-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tetrahydrobiopterin (BH(4)) has a trophic effect on pheochromocytoma-12 (PC12) cells such as insulin-like growth factor-1 (IGF-1). We investigated involvement of BH(4) in the trophic effect of IGF-1 on PC12 cells. IGF-1 (10-300 ng/ml) increased cellular BH(4) content in a dose-related manner. Cellular BH(4) content increased after 6-36 h incubation with IGF-1. IGF-1-induced increase in the cellular BH(4) content was blunted by 0.3 mM 2,4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor for BH(4) synthesis. IGF-1 protected PC12 cells from the cell death induced by depletion of serum and nerve growth factor, which was attenuated by DAHP. The effects of IGF-1 on the cellular BH(4) content and cell viability were eliminated by 0.2 microM wortmannin. These results suggest that BH(4) is involved in the trophic effect of IGF-1 on PC12 cells and that the effect of IGF-1 on BH(4) synthesis is mediated by phosphatidylinositol 3-kinase.
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Affiliation(s)
- Junko Tanaka
- First Division, Department of Medicine, Shimane Medical University, Izumo 693-8501, Japan
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Abstract
In the present study, we have utilized a streptozotocin-induced diabetic mouse model to examine how the diabetic condition and different glucose concentrations affect several parameters of reproductive physiology. We report that oocyte maturation is altered under all experimental conditions examined. In cumulus cell-enclosed oocytes (CEO) from diabetic mice, spontaneous maturation was accelerated but the FSH-mediated delay of spontaneous maturation was suppressed. Higher glucose levels in the culture medium suppressed spontaneous maturation but did not influence the transient arrest mediated by FSH. Meiotic arrest in CEO by hypoxanthine and dibutyryl cAMP (dbcAMP) was less effective at higher glucose concentrations. In addition, both FSH-induced maturation in vitro and hCG-induced maturation in vivo were reduced by the diabetic condition. The ovulation rate was lowered by about 50% in diabetic mice and fewer ovulated ova had reached metaphase II. Despite the decreased number of ova at metaphase II, in vitro cultures showed the oocytes were capable of completing meiotic maturation at control levels. Insulin treatment reversed the detrimental effects of diabetes on meiotic induction, ovulation, and completion of meiotic maturation. Cultures of pronuclear-staged embryos confirmed a negative effect of diabetes and hyperglycemia on development to the blastocyst stage. These data suggest that defects in meiotic regulation brought about by the diabetic condition are due to decreased communication between the somatic and germ cell compartments, and it is concluded that such conditions may contribute to postfertilization developmental abnormalities.
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Gramsbergen JB, Sandberg M, Møller Dall A, Kornblit B, Zimmer J. Glutathione depletion in nigrostriatal slice cultures: GABA loss, dopamine resistance and protection by the tetrahydrobiopterin precursor sepiapterin. Brain Res 2002; 935:47-58. [PMID: 12062472 DOI: 10.1016/s0006-8993(02)02451-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Dopaminergic neurons in culture are preferentially resistant to the toxicity of glutathione (GSH) depletion. This effect may be due to high intrinsic levels of tetrahydrobiopterin (BH(4)). Here we studied the effects of manipulating GSH and/or BH(4) levels on selective neurotoxicity in organotypic nigrostriatal slice cultures. Following treatments with L-buthionine sulfoximine (BSO, 10-100 microM, 2 days exposure, 2 days recovery), either alone or in combination with the BH(4) precursor L-sepiapterin (SEP, 20 microM), or the BH(4) synthesis inhibitor 2,4-diamino-6-hydroxypyrimidine (DAHP, 5 mM), toxic effects were assessed by HPLC analysis of medium and tissues, cellular propidium iodide (PI) uptake, lactate dehydrogenase (LDH) efflux, as well as stereological counting of tyrosine-hydroxylase (TH) positive cells. Thirty micromolar BSO produced 91% GSH and 81% GABA depletion and general cell death, but no significant effect on medium homovanillic acid (HVA) or tissue dopamine (DA) levels. SEP prevented or delayed GABA depletion, PI uptake and LDH efflux by BSO, whereas DAHP in combination with BSO caused (almost) complete loss of medium HVA, tissue DA and TH positive cells. We suggest that under pathological conditions with reduced GSH, impaired synthesis of BH(4) may accelerate nigral cell loss, whereas increasing intracellular BH(4) may provide protection to both DA and GABA neurons.
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Affiliation(s)
- Jan Bert Gramsbergen
- Anatomy and Neurobiology, Institute of Medical Biology, SDU-Odense University, Winsloewparken 21, DK-5000 C Odense, Denmark.
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Stickings P, Cunningham JM. Interleukin-1beta-induced nitric oxide production and inhibition of insulin secretion in rat islets of langerhans is dependent upon the nitric oxide synthase cofactor tetrahidrobiopterin. Cytokine 2002; 18:81-5. [PMID: 12096922 DOI: 10.1006/cyto.2002.0881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interleukin (IL)-1 beta-induced inhibition of glucose-stimulated insulin secretion in rat islets of Langerhans is mediated in part by nitric oxide (NO). The NO synthase cofactor 5,6,7,8-tetrahydrobiopterin (BH(4)) supports NO synthesis in many cell types and IL-1 beta-induced NO generation and inhibition of insulin secretion have been previously correlated with intracellular BH(4 )levels in rat insulinoma cells. Using rat islets and the beta cell line BRIN-BD11, we have investigated whether synthesis of BH(4) limits IL-1beta-induced NO generation and inhibition of glucose-induced insulin secretion. IL-1 beta-induced NO generation by BRIN cells and islets was reduced by 2,4-diamino-6-hydroxypyrimidine (DAHP), an inhibitor of de novo BH(4) synthesis. Sepiapterin, the substrate for salvage pathway BH(4) synthesis, reversed this inhibitory effect of DAHP in islets but not BRIN cells. DAHP reversed IL-1 beta-induced inhibition of islet insulin secretion, an effect prevented by sepiapterin. We conclude that BH(4) generation is necessary for IL-1 beta-induced NO generation in rat islets and BRIN cells. While a contribution of non-NO mediators cannot be excluded, our results support the proposal that IL-1 beta-induced, NO-mediated inhibition of insulin secretion in rat islets is dependent on the NOS cofactor BH(4).
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Affiliation(s)
- P Stickings
- University of Brighton, School of Pharmacy and Biomolecular Sciences, Cockcroft Building, Moulsecoomb, Brighton, BN2 4GJ, UK
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Somasundaram S, Simpson R, Rafi S, Shergill JK, Bjarnason I, Wrigglesworth J. 2, 4-diamino-6- hydroxy pyrimidine inhibits NSAIDs induced nitrosyl-complex EPR signals and ulcer in rat jejunum. BMC Gastroenterol 2002; 2:8. [PMID: 11960558 PMCID: PMC103670 DOI: 10.1186/1471-230x-2-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2001] [Accepted: 04/18/2002] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND It has been suggested that one aspect of non-steroidal anti-inflammatory drugs induced intestinal damage is due to either uncoupling of mitochondrial oxidative phosphorylation or inhibition of electron transport. We investigated the latter possibility using electron paramagnetic resonance spectroscopy. RESULTS Electron paramagnetic studies of NSAIDS on sub-mitochondrial particles revealed that indomethacin, but not with nabumetone, bound to a site near to Complex I and ubiquinone to generate a radical species. Normal rats exhibited prominent [3Fe-4S]ox signals (g approximately 2.01) at 20 K. One hour after indomethacin there was a prominent, intense and broad absorption pattern at (g approximately 2.07) suggesting, appearance of radical species overlapping [3Fe-4S]ox and was unaffected by pretreatment with 2,4 diamino -6-hydroxy pyrimidine. At 24 hrs, when macroscopic ulcers were seen, there was a new signal due to a nitric oxide radical (NO*). In contrast, nabumetone and 2,4 diamino-6-hydroxy pyrimidine pre-treated animals receiving indomethacin exhibited electron paramagnetic resonance spectra identical to those of controls at 24 hrs and neither was associated with small intestinal ulcers. Indomethacin and 2,4 diamino hydroxy pyrimidine pre-treated rats, but not nabumetone, had increased intestinal permeability. CONCLUSION The results suggest that the in vivo effects of indomethacin modulate the mitochondrial respiratory chain directly at 1 h and 24 h through formation of nitric oxide. NO* appears to play an important role in the late pathogenic stages of NSAID enteropathy and may be the site for targeted treatment to reduce their toxicity.
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Affiliation(s)
- S Somasundaram
- Lineberger Comprehensive Cancer Center, CB#7295, University of North Carolina, Chapel Hill, NC 27599, USA.
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Yao Y, Li H, Dong N, Yu Y, Lu L, Shi Z, Sheng Z. [The protective effects and its underlying mechanism of 2,4-diamino-6-hydroxy-pyrimidine on postburn Staphylococcus aureus sepsis in rats]. Zhonghua Shao Shang Za Zhi 2002; 18:84-7. [PMID: 12515652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
OBJECTIVE To investigate the protective effect and its underlying mechanism of 2,4-diamino-6-hydroxy-pyrimidine (DAHP), an inhibitor of GTP-cyclohydrolase I (GTP-CHI), on postburn Staphylococcus aureus (S. aureus) sepsis in rats. METHODS Fifty-six Wistar rats were randomly divided into four groups, i.e. normal control, scalding control, postburn sepsis group and DAHP treatment group. Tissue samples from liver, kidneys, lungs and heart were aseptically taken, and in which the GTP-CHI and inducible nitric oxide synthase (iNOS) contents and the mRNA expression of tumor necrosis factor-alpha (TNFalpha) were determined. Furthermore, biopterin (BH(4)) and nitric oxide (NO) levels in these tissue were also measured. RESULTS After the scalding injury followed by bacterial challenge, the GTP-CHI gene expression and biopterin levels were significantly increased in all tissue sampled, and so were iNOS mRNA expression and NO (P < 0.01), especially in liver and lungs. The expressions of GTP-CHI mRNA and iNOS mRNA and the production of BH(4) and NO in all tissue were evidently inhibited by the pretreatment with DAHP (P < 0.05 approximately 0.01). At the same time, the TNFalpha expression was also obviously decreased. In addition, The mortality at 6 hr in rats of DAHP treatment group was decreased. CONCLUSION The prognosis of the scalding rats complicated by sepsis caused by G(+) bacteria could be improved by DAHP pretreatment, which might be related to the inhibition of the production of BH(4) and NO by DAHP.
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Affiliation(s)
- Yongming Yao
- Burn Institute, The 304th Hospital of PLA, Beijing 100037, P.R. China
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Tanaka J, Koshimura K, Sohmiya M, Murakami Y, Kato Y. Involvement of tetrahydrobiopterin in trophic effect of erythropoietin on PC12 cells. Biochem Biophys Res Commun 2001; 289:358-62. [PMID: 11716480 DOI: 10.1006/bbrc.2001.6002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tetrahydrobiopterin (BH(4)) synthesis is reported to be stimulated by nerve growth factor (NGF) in PC12 cells, suggesting involvement of BH(4) in the trophic effect of NGF. We have recently reported that erythropoietin (EPO) and BH(4) enhance survival of PC12 cells. In the present study, we investigated involvement of BH(4) in the trophic effect of EPO on PC12 cells. Cellular BH(4) content was increased by EPO (10(-10) to 10(-8) M) in a dose- and time-related manner. EPO (10(-10) to 10(-8) M) increased the viable cell number of PC12 cells. In addition to EPO, BH(4) (1, 3, and 10 microM) increased the viable cell number of PC12 cells. Administration of 0.3 mM 2,4-diamino-6-hydroxypyrimidine, an inhibitor of BH(4) synthesis, blunted EPO-induced increases in BH(4) content and the viable cell number of PC12 cells. These results taken together suggest that BH(4) is involved in the trophic effects of EPO on PC12 cells.
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Affiliation(s)
- J Tanaka
- First Division, Department of Medicine, Shimane Medical University, Izumo, Japan
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48
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Abstract
The title compounds were prepared and tested as xanthine oxidase (XO) inhibitors. Results evidenced that potency was related to the position of the oxygen atom in the 2-linear chain and that it grew with distance from the sulfur atom until it became equipotent to 2-n-hexylthiohypoxanthine. Enzymatic oxidation on C(2) occurred in the 8-alkylthiohypoxanthines. On the contrary, oxidation on C(8) did not occur in the 2-alkythioderivatives, demonstrating that the chain forced these molecules to form a complex with molybdenum(VI) involving only the N(3) and N(9) nitrogen atoms.
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Affiliation(s)
- G Biagi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Italy
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Hofer A, Steverding D, Chabes A, Brun R, Thelander L. Trypanosoma brucei CTP synthetase: a target for the treatment of African sleeping sickness. Proc Natl Acad Sci U S A 2001; 98:6412-6. [PMID: 11353848 PMCID: PMC33482 DOI: 10.1073/pnas.111139498] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The drugs in clinical use against African sleeping sickness are toxic, costly, or inefficient. We show that Trypanosoma brucei, which causes this disease, has very low levels of CTP, which are due to a limited capacity for de novo synthesis and the lack of salvage pathways. The CTP synthetase inhibitors 6-diazo-5-oxo-l-norleucine (DON) and alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (acivicin) reduced the parasite CTP levels even further and inhibited trypanosome proliferation in vitro and in T. brucei-infected mice. In mammalian cells, DON mainly inhibits de novo purine biosynthesis, a pathway lacking in trypanosomes. We could rescue DON-treated human and mouse fibroblasts by the addition of the purine base hypoxanthine to the growth medium. For treatment of sleeping sickness, we propose the use of CTP synthetase inhibitors alone or in combination with appropriate nucleosides or bases.
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Affiliation(s)
- A Hofer
- Medical Biochemistry, Department of Medical Biosciences, Umeå University, SE-901 87 Umeå, Sweden.
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Verma S, Yao L, Stewart DJ, Dumont AS, Anderson TJ, McNeill JH. Endothelin antagonism uncovers insulin-mediated vasorelaxation in vitro and in vivo. Hypertension 2001; 37:328-33. [PMID: 11230293 DOI: 10.1161/01.hyp.37.2.328] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The endothelial actions of insulin remain an area of intense research because they relate to both insulin sensitivity and vascular tone. Physiological doses of insulin evoke endothelium-dependent vasorelaxation in humans; however, this remains a pharmacological phenomenon in rat aortas. Because insulin may stimulate the divergent production of both nitric oxide and endothelin-1, we hypothesized that the lack of insulin-induced vasorelaxation at low/subthreshold concentrations may be due to the concurrent production of endothelin-1, which in turn serves to inhibit nitric oxide-dependent, insulin-mediated dilation. To investigate this, we studied the effects of subthreshold concentrations of insulin (100 mU/L) on norepinephrine-induced contraction in rat aortas following short-term and long-term endothelin blockade. In addition, the effects of tetrahydrobiopterin inhibition (with diaminohydroxyprimidine) on norepinephrine-induced contraction in the presence of insulin and endothelin receptor blockade were investigated. Subthreshold concentrations of insulin failed to evoke vasorelaxation in rat aortas. Strikingly, short-term endothelin A/B receptor blockade with bosentan (10(-2) mmol/L) uncovered insulin-mediated dilation; the percent maximum contraction and sensitivity of aortas to norepinephrine were attenuated (% maximum relaxation: bosentan+insulin 74+/-4%* versus bosentan 92+/-3%, insulin 107+/-5% P:<0.002; pD(2) values: bosentan+insulin 6.87+/-0.14* versus bosentan 7.40+/-0.15, insulin 7.63+/-0.11, *P:<0.002). This effect was mediated through endothelin A receptors because bosentan and BQ-123 (10(-2) mmol/L) attenuated norepinephrine-induced contraction to a similar degree. In addition, insulin evoked vasorelaxation in aortas isolated from rats after long-term bosentan treatment (100 mg. kg(-1). d(-1), 3 weeks). The component of insulin-mediated vasorelaxation uncovered by endothelin receptor blockade was tetrahydrobiopterin-dependent because it was reversed by diaminohydroxyprimidine. These data demonstrate, for the first time, the functional interaction between insulin, endothelin-1, and tetrahydrobiopterin in modulating vascular tone in rat aortas in vitro and in vivo.
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Affiliation(s)
- S Verma
- Division of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada.
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