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Xia W, Zhang M, Liu C, Wang S, Xu A, Xia Z, Pang L, Cai Y. Exploring the therapeutic potential of tetrahydrobiopterin for heart failure with preserved ejection fraction: A path forward. Life Sci 2024; 345:122594. [PMID: 38537900 DOI: 10.1016/j.lfs.2024.122594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/10/2024] [Accepted: 03/24/2024] [Indexed: 04/02/2024]
Abstract
A large number of patients are affected by classical heart failure (HF) symptomatology with preserved ejection fraction (HFpEF) and multiorgan syndrome. Due to high morbidity and mortality rate, hospitalization and mortality remain serious socioeconomic problems, while the lack of effective pharmacological or device treatment means that HFpEF presents a major unmet medical need. Evidence from clinical and basic studies demonstrates that systemic inflammation, increased oxidative stress, and impaired mitochondrial function are the common pathological mechanisms in HFpEF. Tetrahydrobiopterin (BH4), beyond being an endogenous co-factor for catalyzing the conversion of some essential biomolecules, has the capacity to prevent systemic inflammation, enhance antioxidant resistance, and modulate mitochondrial energy production. Therefore, BH4 has emerged in the last decade as a promising agent to prevent or reverse the progression of disorders such as cardiovascular disease. In this review, we cover the clinical progress and limitations of using downstream targets of nitric oxide (NO) through NO donors, soluble guanylate cyclase activators, phosphodiesterase inhibitors, and sodium-glucose co-transporter 2 inhibitors in treating cardiovascular diseases, including HFpEF. We discuss the use of BH4 in association with HFpEF, providing new evidence for its potential use as a pharmacological option for treating HFpEF.
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Affiliation(s)
- Weiyi Xia
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Miao Zhang
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China; Shenzhen Second People's Hospital, First Affiliated Hospital of Shenzhen University, Guangdong, China
| | - Chang Liu
- Department of Anesthesiology, The First Hospital of Jilin University, Jilin, China
| | - Sheng Wang
- Department of Anesthesiology, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong SAR, China; Department of Medicine, The University of Hong Kong, Hong Kong SAR, China; Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong SAR, China
| | - Zhengyuan Xia
- Department of Anesthesiology, Affiliated Hospital of Guangdong Medical University, Guangdong, China
| | - Lei Pang
- Department of Anesthesiology, The First Hospital of Jilin University, Jilin, China.
| | - Yin Cai
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong SAR, China; Research Center for Chinese Medicine Innovation, The Hong Kong Polytechnic University, Hong Kong SAR, China; Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China.
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2
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Feng Y, Feng Y, Gu L, Mo W, Wang X, Song B, Hong M, Geng F, Huang P, Yang H, Zhu W, Jiao Y, Zhang Q, Ding WQ, Cao J, Zhang S. Tetrahydrobiopterin metabolism attenuates ROS generation and radiosensitivity through LDHA S-nitrosylation: novel insight into radiogenic lung injury. Exp Mol Med 2024; 56:1107-1122. [PMID: 38689083 PMCID: PMC11148139 DOI: 10.1038/s12276-024-01208-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 05/02/2024] Open
Abstract
Genotoxic therapy triggers reactive oxygen species (ROS) production and oxidative tissue injury. S-nitrosylation is a selective and reversible posttranslational modification of protein thiols by nitric oxide (NO), and 5,6,7,8-tetrahydrobiopterin (BH4) is an essential cofactor for NO synthesis. However, the mechanism by which BH4 affects protein S-nitrosylation and ROS generation has not been determined. Here, we showed that ionizing radiation disrupted the structural integrity of BH4 and downregulated GTP cyclohydrolase I (GCH1), which is the rate-limiting enzyme in BH4 biosynthesis, resulting in deficiency in overall protein S-nitrosylation. GCH1-mediated BH4 synthesis significantly reduced radiation-induced ROS production and fueled the global protein S-nitrosylation that was disrupted by radiation. Likewise, GCH1 overexpression or the administration of exogenous BH4 protected against radiation-induced oxidative injury in vitro and in vivo. Conditional pulmonary Gch1 knockout in mice (Gch1fl/fl; Sftpa1-Cre+/- mice) aggravated lung injury following irradiation, whereas Gch1 knock-in mice (Gch1lsl/lsl; Sftpa1-Cre+/- mice) exhibited attenuated radiation-induced pulmonary toxicity. Mechanistically, lactate dehydrogenase (LDHA) mediated ROS generation downstream of the BH4/NO axis, as determined by iodoacetyl tandem mass tag (iodoTMT)-based protein quantification. Notably, S-nitrosylation of LDHA at Cys163 and Cys293 was regulated by BH4 availability and could restrict ROS generation. The loss of S-nitrosylation in LDHA after irradiation increased radiosensitivity. Overall, the results of the present study showed that GCH1-mediated BH4 biosynthesis played a key role in the ROS cascade and radiosensitivity through LDHA S-nitrosylation, identifying novel therapeutic strategies for the treatment of radiation-induced lung injury.
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Affiliation(s)
- Yang Feng
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
- Department of Oncology, Wuxi No.2 People's Hospital, Jiangnan University Medical Center, 214002, Wuxi, China
| | - Yahui Feng
- Laboratory of Radiation Medicine, Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, 610051, Chengdu, China
| | - Liming Gu
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Wei Mo
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Xi Wang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Bin Song
- West China Second University Hospital, Sichuan University, 610041, Chengdu, China
| | - Min Hong
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Fenghao Geng
- West China Second University Hospital, Sichuan University, 610041, Chengdu, China
| | - Pei Huang
- Department of Oncology, Wuxi No.2 People's Hospital, Jiangnan University Medical Center, 214002, Wuxi, China
| | - Hongying Yang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Wei Zhu
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Yang Jiao
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Qi Zhang
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China
| | - Wei-Qun Ding
- Department of Pathology, Stephenson Cancer Centre, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
| | - Jianping Cao
- State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Medical College of Soochow University, 215123, Suzhou, China.
| | - Shuyu Zhang
- Laboratory of Radiation Medicine, Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, 610051, Chengdu, China.
- West China Second University Hospital, Sichuan University, 610041, Chengdu, China.
- Laboratory of Radiation Medicine, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, 610041, Chengdu, China.
- NHC Key Laboratory of Nuclear Technology Medical Transformation (Mianyang Central Hospital), 621099, Mianyang, China.
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3
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Mahamud N, Songvut P, Muangnoi C, Rodsiri R, Dahlan W, Tansawat R. Untargeted metabolomics reveal pathways associated with neuroprotective effect of oxyresveratrol in SH-SY5Y cells. Sci Rep 2023; 13:20385. [PMID: 37989867 PMCID: PMC10663518 DOI: 10.1038/s41598-023-47558-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 11/15/2023] [Indexed: 11/23/2023] Open
Abstract
Oxyresveratrol has been documented benefits for neurodegenerative disease. However, the specific molecular mechanisms and pathways involved is currently limited. This study aimed to investigate the potential neuroprotective mechanisms of oxyresveratrol using rotenone-induced human neuroblastoma SH-SY5Y cytotoxicity. Cells were divided into the following groups: control, rotenone, and oxyresveratrol pre-treated before being exposed to rotenone. Cellular assays were performed to investigate neuroprotective effects of oxyresveratrol. The results showed that 20 μM oxyresveratrol was effective in preventing rotenone-induced cell death and decreasing ROS levels in the cells. The alteration of metabolites and pathways involved in the neuroprotective activities of oxyresveratrol were further investigated using LC-QTOF-MS/MS untargeted metabolomics approach. We hypothesized that oxyresveratrol's neuroprotective effects would be associated with neurodegenerative pathways. A total of 294 metabolites were identified. 7,8-dihydrobiopterin exhibited the highest VIP scores (VIP > 3.0; p < 0.05), thus considered a biomarker in this study. Our results demonstrated that pretreatment with oxyresveratrol upregulated the level of 7,8-dihydrobiopterin compared to the positive control. Pathway analysis verified that 7,8-dihydrobiopterin was primarily associated with phenylalanine, tyrosine, and tryptophan metabolism (impact = 1, p < 0.001), serving as essential cofactors for enzymatic function in the dopamine biosynthesis pathway. In conclusion, oxyresveratrol may be benefit for the prevention of neurodegenerative diseases by increasing 7,8-dihydrobiopterin concentration.
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Affiliation(s)
- Nureesun Mahamud
- Department of Food and Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
- The Halal Science Center, Chulalongkorn University, Bangkok, Thailand
| | - Phanit Songvut
- Laboratory of Pharmacology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Chawanphat Muangnoi
- Cell and Animal Model Unit, Institute of Nutrition, Mahidol University, Nakhon Pathom, Thailand
| | - Ratchanee Rodsiri
- Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand
- Preclinical Toxicity and Efficacy Assessment of Medicines and Chemicals Research Unit, Chulalongkorn University, Bangkok, Thailand
| | - Winai Dahlan
- The Halal Science Center, Chulalongkorn University, Bangkok, Thailand
| | - Rossarin Tansawat
- Department of Food and Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.
- Metabolomics for Life Sciences Research Unit, Chulalongkorn University, Bangkok, Thailand.
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Fernando V, Zheng X, Sharma V, Furuta S. Reprogramming of breast tumor-associated macrophages with modulation of arginine metabolism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554238. [PMID: 37662241 PMCID: PMC10473631 DOI: 10.1101/2023.08.22.554238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
HER2+ breast tumors have abundant immune-suppressive cells, including M2-type tumor associated macrophages (TAMs). While TAMs consist of the immune-stimulatory M1-type and immune-suppressive M2-type, M1/M2-TAM ratio is reduced in immune-suppressive tumors, contributing to their immunotherapy refractoriness. M1 vs. M2-TAM formation depends on differential arginine metabolism, where M1-TAMs convert arginine to nitric oxide (NO) and M2-TAMs convert arginine to polyamines (PAs). We hypothesize that such distinct arginine metabolism in M1- vs M2-TAMs is attributed to different availability of BH4 (NO synthase cofactor) and that its replenishment would reprogram M2-TAMs to M1-TAMs. Recently, we reported that sepiapterin (SEP), the endogenous BH4 precursor, elevates the expression of M1-TAM markers within HER2+ tumors. Here, we show that SEP restores BH4 levels in M2-TAMs, which then redirects arginine metabolism to NO synthesis and converts M2-TAMs to M1-TAMs. The reprogrammed TAMs exhibit full-fledged capabilities of antigen presentation and induction of effector T cells to trigger immunogenic cell death of HER2+ cancer cells. This study substantiates the utility of SEP in metabolic shift of HER2+ breast tumor microenvironment as a novel immunotherapeutic strategy.
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Affiliation(s)
- Veani Fernando
- Department of Cell & Cancer Biology, College of Medicine and Life Sciences, University of Toledo Health Science Campus, 3000 Arlington Ave. Toledo, OH 43614, USA
- Division of Rheumatology, University of Colorado, Anschutz Medical Campus Barbara Davis Center, Mail Stop B115, 1775 Aurora Court, Aurora, Colorado 80045
| | - Xunzhen Zheng
- Department of Cell & Cancer Biology, College of Medicine and Life Sciences, University of Toledo Health Science Campus, 3000 Arlington Ave. Toledo, OH 43614, USA
| | - Vandana Sharma
- Department of Cell & Cancer Biology, College of Medicine and Life Sciences, University of Toledo Health Science Campus, 3000 Arlington Ave. Toledo, OH 43614, USA
| | - Saori Furuta
- Department of Cell & Cancer Biology, College of Medicine and Life Sciences, University of Toledo Health Science Campus, 3000 Arlington Ave. Toledo, OH 43614, USA
- MetroHealth Medical Center, Case Western Reserve University School of Medicine, Case Comprehensive Cancer Center, 2500 MetroHealth Drive, Cleveland, OH 44109
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5
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Leuzzi V, Galosi S. Experimental pharmacology: Targeting metabolic pathways. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 169:259-315. [PMID: 37482395 DOI: 10.1016/bs.irn.2023.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Since the discovery of the treatment for Wilson disease a growing number of treatable inherited dystonias have been identified and their search and treatment have progressively been implemented in the clinics of patients with dystonia. While waiting for gene therapy to be more widely and adequately translated into the clinical setting, the efforts to divert the natural course of dystonia reside in unveiling its pathogenesis. Specific metabolic treatments can rewrite the natural history of the disease by preventing neurotoxic metabolite accumulation or interfering with the cell accumulation of damaging metabolites, restoring energetic cell fuel, supplementing defective metabolites, and supplementing the defective enzyme. A metabolic derangement of cell homeostasis is part of the progression of many non-metabolic genetic lesions and could be the target for possible metabolic approaches. In this chapter, we provided an update on treatment strategies for treatable inherited dystonias and an overview of genetic dystonias with new experimental therapeutic approaches available or close to clinical translation.
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Affiliation(s)
- Vincenzo Leuzzi
- Department of Human Neuroscience, Sapienza University, Rome, Italy
| | - Serena Galosi
- Department of Human Neuroscience, Sapienza University, Rome, Italy.
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Chu SM, Heather LC, Chuaiphichai S, Nicol T, Wright B, Miossec M, Bendall JK, Douglas G, Crabtree MJ, Channon KM. Cardiomyocyte tetrahydrobiopterin synthesis regulates fatty acid metabolism and susceptibility to ischaemia-reperfusion injury. Exp Physiol 2023; 108:874-890. [PMID: 37184360 PMCID: PMC10988529 DOI: 10.1113/ep090795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/07/2023] [Indexed: 05/16/2023]
Abstract
NEW FINDINGS What is the central question of this study? What are the physiological roles of cardiomyocyte-derived tetrahydrobiopterin (BH4) in cardiac metabolism and stress response? What is the main finding and its importance? Cardiomyocyte BH4 has a physiological role in cardiac metabolism. There was a shift of substrate preference from fatty acid to glucose in hearts with targeted deletion of BH4 synthesis. The changes in fatty-acid metabolic profile were associated with a protective effect in response to ischaemia-reperfusion (IR) injury, and reduced infarct size. Manipulating fatty acid metabolism via BH4 availability could play a therapeutic role in limiting IR injury. ABSTRACT Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide (NO) synthases in which its production of NO is crucial for cardiac function. However, non-canonical roles of BH4 have been discovered recently and the cell-specific role of cardiomyocyte BH4 in cardiac function and metabolism remains to be elucidated. Therefore, we developed a novel mouse model of cardiomyocyte BH4 deficiency, by cardiomyocyte-specific deletion of Gch1, which encodes guanosine triphosphate cyclohydrolase I, a required enzyme for de novo BH4 synthesis. Cardiomyocyte (cm)Gch1 mRNA expression and BH4 levels from cmGch1 KO mice were significantly reduced compared to Gch1flox/flox (WT) littermates. Transcriptomic analyses and protein assays revealed downregulation of genes involved in fatty acid oxidation in cmGch1 KO hearts compared with WT, accompanied by increased triacylglycerol concentration within the myocardium. Deletion of cardiomyocyte BH4 did not alter basal cardiac function. However, the recovery of left ventricle function was improved in cmGch1 KO hearts when subjected to ex vivo ischaemia-reperfusion (IR) injury, with reduced infarct size compared to WT hearts. Metabolomic analyses of cardiac tissue after IR revealed that long-chain fatty acids were increased in cmGch1 KO hearts compared to WT, whereas at 5 min reperfusion (post-35 min ischaemia) fatty acid metabolite levels were higher in WT compared to cmGch1 KO hearts. These results indicate a new role for BH4 in cardiomyocyte fatty acid metabolism, such that reduction of cardiomyocyte BH4 confers a protective effect in response to cardiac IR injury. Manipulating cardiac metabolism via BH4 could play a therapeutic role in limiting IR injury.
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Affiliation(s)
- Sandy M. Chu
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Lisa C. Heather
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordOxfordUK
| | - Surawee Chuaiphichai
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Thomas Nicol
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Benjamin Wright
- Oxford Genomics Centre, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Matthieu Miossec
- Oxford Genomics Centre, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Jennifer K. Bendall
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Gillian Douglas
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Mark J. Crabtree
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
| | - Keith M. Channon
- Division of Cardiovascular Medicine, British Heart Foundation Centre of Research Excellence, Radcliffe Department of MedicineUniversity of OxfordOxfordUK
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Bratkovic D, Margvelashvili L, Tchan MC, Nisbet J, Smith N. PTC923 (sepiapterin) lowers elevated blood phenylalanine in subjects with phenylketonuria: a phase 2 randomized, multi-center, three-period crossover, open-label, active controlled, all-comers study. Metabolism 2022; 128:155116. [PMID: 34973284 DOI: 10.1016/j.metabol.2021.155116] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 10/21/2021] [Accepted: 12/21/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND & AIM PTC923 (formerly CNSA-001), an oral formulation of sepiapterin, a natural precursor of intracellular tetrahydrobiopterin (BH4), has been shown in humans to induce larger increases in circulating BH4 vs. sapropterin dihydrochloride. Sapropterin reduces blood phenylalanine (Phe) by ≥20-30% in a minority of subjects with PKU. This was a Phase 2 randomized, multicenter, three-period crossover, open-label, active controlled, all-comers [regardless of phenylalanine hydroxylase (PAH) variants] comparison of PTC923 60 mg/kg, PTC923 20 mg/kg and sapropterin 20 mg/kg in 24 adults with phenylketonuria (PKU) and hyperphenylalaninemia. METHODS Eligible subjects were adult men or women (18-60 y) with PKU. Subjects enrolled received 7 days of once-daily oral treatment with PTC923 20 mg/kg/day, PTC923 60 mg/kg/day and sapropterin dihydrochloride 20 mg/kg/day each in a random order. Treatments were separated by a 7-day washout. Subjects maintained their usual pre-study diet, including consumption of amino acid mixtures. Blood Phe was measured on Day 1 (predose baseline), Day 3, Day 5, and Day 7 of each treatment period. RESULTS Least squares mean changes (SE) from baseline in blood Phe were: -206.4 (41.8) μmol/L for PTC923 60 mg/kg (p < 0.0001); -146.9 (41.8) μmol/L for PTC923 20 mg/kg (p = 0.0010); and - 91.5 (41.7) μmol/L for sapropterin (p = 0.0339). Effects of PTC923 60 mg/kg on blood Phe vs. sapropterin were significantly larger (p = 0.0098) and faster in onset with a significantly larger mean reduction in blood Phe at day 3 of treatment, p = 0.0135 (20 mg/kg) and p = 0.0007 (60 mg/kg). Only PTC923 60 mg/kg reduced blood Phe in classical PKU subjects (n = 11, p = 0.0287). The mean blood Phe reduction (PTC923 60 mg/kg) in a cofactor responder analysis (n = 8; baseline Phe ≥300 μmol/L and blood Phe reduction ≥30%) was -463.3 μmol/L (SE 51.5) from baseline. Adverse events were mostly mild to moderate, transient, and similar across treatment groups with no serious adverse events or discontinuations. CONCLUSIONS The substantially significantly better effect of PTC923 60 mg/kg on blood Phe reduction vs. sapropterin supports further clinical development of PTC923 for PKU; ANZCTR number, ACTRN12618001031257.
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Affiliation(s)
- Drago Bratkovic
- PARC Clinical Research, Royal Adelaide Hospital, South Australia, Australia
| | | | - Michel C Tchan
- Department of Genetic Medicine, Westmead Hospital, Australia and University of Sydney, Sydney, New South Wales, Australia
| | - Janelle Nisbet
- Mater Misericordiae Limited, Queensland Diabetes and Endocrine Centre, Brisbane, Queensland, Australia
| | - Neil Smith
- PTC Therapeutics Inc, South Plainfield, NJ, USA.
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Fujihara Y, Kodo Y, Miyoshi SI, Watanabe R, Toyoda H, Mankura M, Kabuto H, Takayama F. Spirulina platensis and its ingredient biopterin glucoside improved insulin sensitivity in non-alcoholic steatohepatitis model. J Clin Biochem Nutr 2021; 69:151-157. [PMID: 34616107 PMCID: PMC8482380 DOI: 10.3164/jcbn.20-201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 12/25/2020] [Indexed: 11/25/2022] Open
Abstract
Non-alcoholic steatohepatitis is the chronic liver disease leading to cirrhosis and cancer and its prevalence is increasing. Some agents are under clinical trials for non-alcoholic steatohepatitis treatment. We previously reported Spirulina (Arthrospira) platensis effectively prevented non-alcoholic steatohepatitis progression in our model rats. The contribution of phycocyanin, an ingredient of Spirulina (Arthrospira) platensis, was limited. We, therefore, have looked for more active components of Spirulina (Arthrospira) platensis. In this study, we pursued the effect of biopterin glucoside, another bioactive ingredient of Spirulina (Arthrospira) platensis. We found Spirulina (Arthrospira) platensis and biopterin glucoside oral administrations effectively alleviated oxidative stress, inflammation and insulin signal failure, and prevented fibroblast growth factor 21 gene overexpression in non-alcoholic steatohepatitis rat livers. We concluded biopterin glucoside is a major component of Spirulina (Arthrospira) platensis action.
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Affiliation(s)
- Yuri Fujihara
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Yasumasa Kodo
- Spirulina BioLab. Co., Ltd., 1-13-6 Nishinakajima, Yodogawa-ku, Osaka 532-0011, Japan
| | - Shin-Ichi Miyoshi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
| | - Ritsuko Watanabe
- Okayama Kyoritsu General Hospital, 8-10 Akasakahonmachi, Naka-ku, Okayama 703-8288, Japan
| | - Hiroshi Toyoda
- Okayama Kyoritsu General Hospital, 8-10 Akasakahonmachi, Naka-ku, Okayama 703-8288, Japan
| | - Mitsumasa Mankura
- Kurashiki Sakuyo University, 3515 Tamashima Nagao, Kurashiki, Okayama 710-0292, Japan
| | - Hideaki Kabuto
- Kagawa Prefectural College of Health Sciences, 281-1 Murechohara, Takamatsu, Kagawa 761-0123, Japan
| | - Fusako Takayama
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
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9
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Abell TL, Garcia LM, Wiener GJ, Wo JM, Bulat RS, Smith N. Effect of Oral CNSA-001 (sepiapterin, PTC923) on gastric accommodation in women with diabetic gastroparesis: A randomized, placebo-controlled, Phase 2 trial. J Diabetes Complications 2021; 35:107961. [PMID: 34176722 DOI: 10.1016/j.jdiacomp.2021.107961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/12/2021] [Accepted: 05/16/2021] [Indexed: 12/11/2022]
Abstract
AIMS Diabetic gastroparesis may be associated with impaired nitric oxide metabolism and reduced tetrahydrobiopterin (BH4) synthesis. Oral treatment with CNSA-001 (sepiapterin, currently known as PTC923) increased BH4 levels in humans in a previous study. This Phase 2 study evaluated CNSA-001 in women with diabetic gastroparesis. METHODS Non-pregnant diabetic women with moderate/severe symptomatic gastroparesis, delayed gastric emptying, and impaired gastric accommodation (nutrient satiety testing) were randomized to 10mg/kg BID CNSA-001 or matching placebo for 14days. The primary endpoint was change in gastric accommodation (maximal tolerated liquid meal volume) at 14- and 28-days' follow-up. RESULTS Gastric accommodation improved in CNSA-001-treated vs. placebo-treated subjects at 28days (least squares mean [LSM] difference: 98 [95% CI 36 to 161], p=0.0042). Subjects' ratings of bloating, fullness, nausea, and pain were lower vs. baseline in the CNSA-001 group at 14 and 28days, though these improvements were not observed consistently in placebo-treated subjects. There were no significant group differences in upper gastrointestinal symptom scores, and in gastric emptying breath test parameters. CNSA-001 was well tolerated, with no withdrawals for adverse events. CONCLUSIONS CNSA-001 improved gastric accommodation in women with diabetic gastroparesis. Further evaluation of CNSA-001 in gastroparesis is warranted; ClinicalTrials.gov number, NCT03712124.
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Affiliation(s)
| | | | | | - John M Wo
- Indiana University Hospital, Indianapolis, IN, USA
| | - Robert S Bulat
- Johns Hopkins Center for Neurogastroenterology, Baltimore, MD, USA
| | - Neil Smith
- PTC Therapeutics Inc., South Plainfield, NJ, USA.
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Fanet H, Capuron L, Castanon N, Calon F, Vancassel S. Tetrahydrobioterin (BH4) Pathway: From Metabolism to Neuropsychiatry. Curr Neuropharmacol 2021; 19:591-609. [PMID: 32744952 PMCID: PMC8573752 DOI: 10.2174/1570159x18666200729103529] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/03/2020] [Accepted: 07/23/2020] [Indexed: 11/22/2022] Open
Abstract
Tetrahydrobipterin (BH4) is a pivotal enzymatic cofactor required for the synthesis of serotonin, dopamine and nitric oxide. BH4 is essential for numerous physiological processes at periphery and central levels, such as vascularization, inflammation, glucose homeostasis, regulation of oxidative stress and neurotransmission. BH4 de novo synthesis involves the sequential activation of three enzymes, the major controlling point being GTP cyclohydrolase I (GCH1). Complementary salvage and recycling pathways ensure that BH4 levels are tightly kept within a physiological range in the body. Even if the way of transport of BH4 and its ability to enter the brain after peripheral administration is still controversial, data showed increased levels in the brain after BH4 treatment. Available evidence shows that GCH1 expression and BH4 synthesis are stimulated by immunological factors, notably pro-inflammatory cytokines. Once produced, BH4 can act as an anti- inflammatory molecule and scavenger of free radicals protecting against oxidative stress. At the same time, BH4 is prone to autoxidation, leading to the release of superoxide radicals contributing to inflammatory processes, and to the production of BH2, an inactive form of BH4, reducing its bioavailability. Alterations in BH4 levels have been documented in many pathological situations, including Alzheimer's disease, Parkinson's disease and depression, in which increased oxidative stress, inflammation and alterations in monoaminergic function are described. This review aims at providing an update of the knowledge about metabolism and the role of BH4 in brain function, from preclinical to clinical studies, addressing some therapeutic implications.
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Affiliation(s)
- H. Fanet
- INRAe, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- Université de Bordeaux, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
- Neurosciences Axis, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada
- OptiNutriBrain International Associated Laboratory (NurtriNeuro France-INAF Canada), Quebec City, Canada
| | - L. Capuron
- INRAe, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- Université de Bordeaux, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- OptiNutriBrain International Associated Laboratory (NurtriNeuro France-INAF Canada), Quebec City, Canada
| | - N. Castanon
- INRAe, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- Université de Bordeaux, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- OptiNutriBrain International Associated Laboratory (NurtriNeuro France-INAF Canada), Quebec City, Canada
| | - F. Calon
- Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
- Neurosciences Axis, Centre de Recherche du CHU de Québec-Université Laval, Quebec City, QC, Canada
- OptiNutriBrain International Associated Laboratory (NurtriNeuro France-INAF Canada), Quebec City, Canada
| | - S. Vancassel
- INRAe, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- Université de Bordeaux, Nutrition and Integrated Neurobiology, UMR 1286, Bordeaux, France
- OptiNutriBrain International Associated Laboratory (NurtriNeuro France-INAF Canada), Quebec City, Canada
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11
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Arai H, Takahashi R, Sakamoto Y, Kitano T, Mashita O, Hara S, Yoshikawa S, Kawasaki K, Ichinose H. Peripheral tetrahydrobiopterin is involved in the pathogenesis of mechanical hypersensitivity in a rodent postsurgical pain model. Pain 2020; 161:2520-2531. [PMID: 32541389 DOI: 10.1097/j.pain.0000000000001946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Because treatment for postsurgical pain (PSP) remains a major unmet medical need, the emergence of safe and innovative nonopioid drugs has been strongly coveted. Tetrahydrobiopterin (BH4) is an interesting molecule for gaining a better understanding the pathological mechanism of neuropathic pain. However, whether BH4 and its pathway are involved in the pathogenesis of PSP remains unclear. In this study, we found that early in a rat paw incision model, the gene expression of GTP cyclohydrolase 1 (GTPCH) and sepiapterin reductase (SPR), BH4-producing enzymes in the de novo pathway, were significantly increased in incised compared with naive paw skin. Although a significant increase in GTPCH protein levels was observed in incised paw skin until only 1 day after incision, a significant increase in BH4 levels was observed until 7 days after incision. In vivo, Spr-knockout mice showed an antinociceptive phenotype in the hind paw incision compared with the wild-type and Spr heterozygote groups. Furthermore, QM385, the SPR inhibitor, showed a significant dose-dependent, antinociceptive effect, which was supported by a reduction in BH4 levels in incised skin tissues, with no apparent adverse effects. Immunohistochemical analysis demonstrated that macrophages expressing GTPCH protein were increased around the injury site in the rat paw incision model. These results indicate that BH4 is involved in the pathogenesis of PSP, and that inhibition of the BH4 pathway could provide a new strategy for the treatment of acute PSP.
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Affiliation(s)
- Hirokazu Arai
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Laboratory for Pharmacology, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Rina Takahashi
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yoshiaki Sakamoto
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Tatsuya Kitano
- Laboratory for Pharmacology, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Okishi Mashita
- Laboratory for Safety Assessment and ADME, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Satoshi Hara
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Satoru Yoshikawa
- Laboratory for Pharmacology, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Koh Kawasaki
- Laboratory for Pharmacology, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Hiroshi Ichinose
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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12
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Evers RAF, van Vliet D, van Spronsen FJ. Tetrahydrobiopterin treatment in phenylketonuria: A repurposing approach. J Inherit Metab Dis 2020; 43:189-199. [PMID: 31373030 DOI: 10.1002/jimd.12151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/01/2019] [Accepted: 07/04/2019] [Indexed: 12/24/2022]
Abstract
In phenylketonuria (PKU) patients, early diagnosis by neonatal screening and immediate institution of a phenylalanine-restricted diet can prevent severe intellectual impairment. Nevertheless, outcome remains suboptimal in some patients asking for additional treatment strategies. Tetrahydrobiopterin (BH4 ) could be one of those treatment options, as it may not only increase residual phenylalanine hydroxylase activity in BH4 -responsive PKU patients, but possibly also directly improves neurocognitive functioning in both BH4 -responsive and BH4 -unresponsive PKU patients. In the present review, we aim to further define the theoretical working mechanisms by which BH4 might directly influence neurocognitive functioning in PKU having passed the blood-brain barrier. Further research should investigate which of these mechanisms are actually involved, and should contribute to the development of an optimal BH4 treatment regimen to directly improve neurocognitive functioning in PKU. Such possible repurposing approach of BH4 treatment in PKU may improve neuropsychological outcome and mental health in both BH4 -responsive and BH4 -unresponsive PKU patients.
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Affiliation(s)
- Roeland A F Evers
- Division of Metabolic Diseases, University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, The Netherlands
| | - Danique van Vliet
- Division of Metabolic Diseases, University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, The Netherlands
| | - Francjan J van Spronsen
- Division of Metabolic Diseases, University of Groningen, University Medical Center Groningen, Beatrix Children's Hospital, Groningen, The Netherlands
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13
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Smith N, Longo N, Levert K, Hyland K, Blau N. Phase I clinical evaluation of CNSA-001 (sepiapterin), a novel pharmacological treatment for phenylketonuria and tetrahydrobiopterin deficiencies, in healthy volunteers. Mol Genet Metab 2019; 126:406-412. [PMID: 30922814 DOI: 10.1016/j.ymgme.2019.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/07/2019] [Accepted: 02/07/2019] [Indexed: 01/14/2023]
Abstract
Tetrahydrobiopterin (BH4) is the natural cofactor of aromatic amino acid hydroxylases and essential for degradation of phenylalanine and synthesis of catecholamines and serotonin. It can be synthesized either de novo from GTP or through the salvage pathway from sepiapterin. Sepiapterin, a natural precursor of BH4, is a more stable molecule and is transported more efficiently across cellular membranes, thus having potentially significant advantage over BH4 as a pharmacological agent for diseases associated with BH4-deficient conditions. We report the results of a first-in-humans, randomized, double-blind, placebo-controlled, dose-ranging, Phase I clinical trial in 83 healthy volunteers of CNSA-001, a novel formulation of sepiapterin. Single oral doses of 2.5-80 mg/kg CNSA-001 caused dose-related increases in plasma sepiapterin (mean Cmax 0.58-2.92 ng/mL) and BH4 (mean Cmax 57-312 ng/mL). Maximum plasma concentrations were achieved in about 1-2 h (sepiapterin) or about 4 h (BH4) after CNSA-001 oral intake. Increases in plasma BH4 were substantially larger in absolute terms and on a dose-for-dose basis following treatment with CNSA-001 vs. sapropterin dihydrochloride, a synthetic form of BH4. The pharmacokinetics of plasma sepiapterin and BH4 were similar before and after seven days of repeat daily dosing with CNSA-001 at 5, 20 or 60 mg/kg indicating little or no drug accumulation. Oral administration of CNSA-001 resulted in higher concentrations of sepiapterin in fasted vs. fed subjects, but overall BH4 plasma exposure following CNSA-001 intake increased by 1.7-1.8-fold in fed subjects. CNSA-001 was well tolerated, with no clear dose-relationship for adverse events (AE), no serious AE and no study discontinuations for AE. These data indicate that CNSA-001 is rapidly and efficiently converted to BH4 in humans supporting further clinical evaluation of CNSA-001 for the management of PKU, primary BH4 deficiencies and other diseases associated with deficient BH4 metabolism.
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Affiliation(s)
- Neil Smith
- Censa Pharmaceuticals Inc., Wellesley, MA, USA.
| | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
| | | | | | - Nenad Blau
- Dietmar-Hopp-Metabolic Center, University Children's Hospital, Heidelberg, Germany; Division of Metabolism, University Children's Hospital, Zurich, Switzerland.
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14
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Latremoliere A, Costigan M. Combining Human and Rodent Genetics to Identify New Analgesics. Neurosci Bull 2018; 34:143-155. [PMID: 28667479 PMCID: PMC5799129 DOI: 10.1007/s12264-017-0152-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 06/01/2017] [Indexed: 12/26/2022] Open
Abstract
Most attempts at rational development of new analgesics have failed, in part because chronic pain involves multiple processes that remain poorly understood. To improve translational success, one strategy is to select novel targets for which there is proof of clinical relevance, either genetically through heritable traits, or pharmacologically. Such an approach by definition yields targets with high clinical validity. The biology of these targets can be elucidated in animal models before returning to the patients with a refined therapeutic. For optimal treatment, having biomarkers of drug action available is also a plus. Here we describe a case study in rational drug design: the use of controlled inhibition of peripheral tetrahydrobiopterin (BH4) synthesis to reduce abnormal chronic pain states without altering nociceptive-protective pain. Initially identified in a population of patients with low back pain, the association between BH4 production and chronic pain has been confirmed in more than 12 independent cohorts, through a common haplotype (present in 25% of Caucasians) of the rate-limiting enzyme for BH4 synthesis, GTP cyclohydrolase 1 (GCH1). Genetic tools in mice have demonstrated that both injured sensory neurons and activated macrophages engage increased BH4 synthesis to cause chronic pain. GCH1 is an obligate enzyme for de novo BH4 production. Therefore, inhibiting GCH1 activity eliminates all BH4 production, affecting the synthesis of multiple neurotransmitters and signaling molecules and interfering with physiological function. In contrast, targeting the last enzyme of the BH4 synthesis pathway, sepiapterin reductase (SPR), allows reduction of pathological BH4 production without completely blocking physiological BH4 synthesis. Systemic SPR inhibition in mice has not revealed any safety concerns to date, and available genetic and pharmacologic data suggest similar responses in humans. Finally, because it is present in vivo only when SPR is inhibited, sepiapterin serves as a reliable biomarker of target engagement, allowing potential quantification of drug efficacy. The emerging development of therapeutics that target BH4 synthesis to treat chronic pain illustrates the power of combining human and mouse genetics: human genetic studies for clinical selection of relevant targets, coupled with causality studies in mice, allowing the rational engineering of new analgesics.
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Affiliation(s)
- Alban Latremoliere
- Kirby Neurobiology Center, Boston Children's Hospital and Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Michael Costigan
- Kirby Neurobiology Center, Boston Children's Hospital and Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Anesthesiology, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, MA, 02115, USA.
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15
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Ohashi A, Mamada K, Harada T, Naito M, Takahashi T, Aizawa S, Hasegawa H. Organic anion transporters, OAT1 and OAT3, are crucial biopterin transporters involved in bodily distribution of tetrahydrobiopterin and exclusion of its excess. Mol Cell Biochem 2017; 435:97-108. [PMID: 28534121 PMCID: PMC5632347 DOI: 10.1007/s11010-017-3060-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 05/04/2017] [Indexed: 01/05/2023]
Abstract
Tetrahydrobiopterin (BH4) is a common coenzyme of phenylalanine-, tyrosine-, and tryptophan hydroxylases, alkylglycerol monooxygenase, and NO synthases (NOS). Synthetic BH4 is used medicinally for BH4-responsive phenylketonuria and inherited BH4 deficiency. BH4 supplementation has also drawn attention as a therapy for various NOS-related cardio-vascular diseases, but its use has met with limited success in decreasing BH2, the oxidized form of BH4. An increase in the BH2/BH4 ratio leads to NOS dysfunction. Previous studies revealed that BH4 supplementation caused a rapid urinary loss of BH4 accompanied by an increase in the blood BH2/BH4 ratio and an involvement of probenecid-sensitive but unknown transporters was strongly suggested in these processes. Here we show that OAT1 and OAT3 enabled cells to take up BP (BH4 and/or BH2) in a probenecid-sensitive manner using rat kidney slices and transporter-expressing cell systems, LLC-PK1 cells and Xenopus oocytes. Both OAT1 and OAT3 preferred BH2 and sepiapterin as their substrate roughly 5- to 10-fold more than BH4. Administration of probenecid acutely reduced the urinary exclusion of endogenous BP accompanied by a rise in blood BP in vivo. These results indicated that OAT1 and OAT3 played crucial roles: (1) in determining baseline levels of blood BP by excluding endogenous BP through the urine, (2) in the rapid distribution to organs of exogenous BH4 and the exclusion to urine of a BH4 excess, particularly when BH4 was administered, and (3) in scavenging blood BH2 by cellular uptake as the gateway to the salvage pathway of BH4, which reduces BH2 back to BH4.
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Affiliation(s)
- Akiko Ohashi
- Department of Anatomy, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda, Tokyo, 101-8310, Japan.
- Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Chiyoda, Tokyo, 101-8310, Japan.
| | - Kaori Mamada
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi, 401-0193, Japan
| | - Tomonori Harada
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
| | - Masako Naito
- Department of Anatomy, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda, Tokyo, 101-8310, Japan
- Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Chiyoda, Tokyo, 101-8310, Japan
| | - Tomihisa Takahashi
- Department of Anatomy, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda, Tokyo, 101-8310, Japan
- Division of Functional Morphology, Dental Research Center, Nihon University School of Dentistry, Chiyoda, Tokyo, 101-8310, Japan
| | - Shin Aizawa
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
| | - Hiroyuki Hasegawa
- Department of Anatomy, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda, Tokyo, 101-8310, Japan
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16
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Joshi S, Kar S, Kavdia M. Computational analysis of interactions of oxidative stress and tetrahydrobiopterin reveals instability in eNOS coupling. Microvasc Res 2017; 114:114-128. [PMID: 28729163 DOI: 10.1016/j.mvr.2017.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/11/2017] [Accepted: 07/11/2017] [Indexed: 01/30/2023]
Abstract
In cardiovascular and neurovascular diseases, an increase in oxidative stress and endothelial dysfunction has been reported. There is a reduction in tetrahydrobiopterin (BH4), which is a cofactor for the endothelial nitric oxide synthase (eNOS), resulting in eNOS uncoupling. Studies of the enhancement of BH4 availability have reported mixed results for improvement in endothelial dysfunction. Our understanding of the complex interactions of eNOS uncoupling, oxidative stress and BH4 availability is not complete and a quantitative understanding of these interactions is required. In the present study, we developed a computational model for eNOS uncoupling that considers the temporal changes in biopterin ratio in the oxidative stress conditions. Using the model, we studied the effects of cellular oxidative stress (Qsupcell) representing the non-eNOS based oxidative stress sources and BH4 synthesis (QBH4) on eNOS NO production and biopterin ratio (BH4/total biopterins (TBP)). Model results showed that oxidative stress levels from 0.01 to 1nM·s-1 did not affect eNOS NO production and eNOS remained in coupled state. When the Qsupcell increased above 1nM·s-1, the eNOS coupling and NO production transitioned to an oscillatory state. Oxidative stress levels dynamically changed the biopterin ratio. When Qsupcell increased from 1 to 100nM·s-1, the endothelial cell NO production, TBP levels and biopterin ratio reduced significantly from 26.5 to 2nM·s-1, 3.75 to 0.002μM and 0.99 to 0.25, respectively. For an increase in BH4 synthesis, the improvement in NO production rate and BH4 levels were dependent on the extent of cellular oxidative stress. However, a 10-fold increase in QBH4 at higher oxidative stresses did not restore the NO-production rate and the biopterin ratio. Our mechanistic analysis reveals that a combination of enhancing tetrahydrobiopterin level with a reduction in cellular oxidative stress may result in significant improvement in endothelial dysfunction.
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Affiliation(s)
- Sheetal Joshi
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA
| | - Saptarshi Kar
- Engineering Computational Biology Group, University of Western Australia, Crawley, WA 6009, Australia
| | - Mahendra Kavdia
- Department of Biomedical Engineering, Wayne State University, Detroit, MI 48202, USA.
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17
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Components of the folate metabolic pathway and ADHD core traits: an exploration in eastern Indian probands. J Hum Genet 2017; 62:687-695. [PMID: 28250422 DOI: 10.1038/jhg.2017.23] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 01/11/2023]
Abstract
We investigated role of the folate-homocysteine metabolic pathway in the etiology of attention-deficit hyperactivity disorder (ADHD) due to its importance in maintaining DNA integrity as well as neurotransmission. Functional gene variants in MTR (rs1805087), CBS (rs5742905), MTHFR (rs1801133 &rs1801131), MTHFD (rs2236225), RFC1 (rs1051266), plasma vitamin B12, folate and homocysteine were analyzed. rs1805087 'A' showed strong association with ADHD. Vitamin B12 deficiency of ADHD probands (P=0.01) correlated with rs1801133 'T' and rs1805087'GG'. Mild hyperhomocysteinemia (P=0.05) in the probands was associated with rs1805087 'AA'. Probands having rs1805087 'GG' and rs1051266 'G' was more inattentive. Hyperactivity-impulsivity score revealed association with rs5742905 'TT' and rs2236225 'CC', while rs1801133 'CC' showed association with inattentiveness and hyperactivity-impulsivity. rs1801131 exhibited strong synergistic interaction with rs1051266 and rs2236225. This indicated that the folate-homocysteine pathway gene variants may affect ADHD etiology through mild hyperhomocysteinemia and vitamin B12 deficiency, factors known to be associated with cognitive deficit.
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18
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Ohashi A, Saeki Y, Harada T, Naito M, Takahashi T, Aizawa S, Hasegawa H. Tetrahydrobiopterin Supplementation: Elevation of Tissue Biopterin Levels Accompanied by a Relative Increase in Dihydrobiopterin in the Blood and the Role of Probenecid-Sensitive Uptake in Scavenging Dihydrobiopterin in the Liver and Kidney of Rats. PLoS One 2016; 11:e0164305. [PMID: 27711248 PMCID: PMC5053593 DOI: 10.1371/journal.pone.0164305] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 09/22/2016] [Indexed: 12/21/2022] Open
Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor of nitric oxide synthase (NOS) and aromatic amino acid hydroxylases. BH4 and 7,8-dihydrobiopterin (BH2) are metabolically interchangeable at the expense of NADPH. Exogenously administered BH4 can be metabolized by the body, similar to vitamins. At present, synthetic BH4 is used as an orphan drug for patients with inherited diseases requiring BH4 supplementation. BH4 supplementation has also drawn attention as a means of treating certain cardiovascular symptoms, however, its application in human patients remains limited. Here, we tracked biopterin (BP) distribution in blood, bile, urine, liver, kidney and brain after BH4 administration (5 mg/kg rat, i.v.) with or without prior treatment with probenecid, a potent inhibitor of uptake transporters particularly including organic anion transporter families such as OTA1 and OAT3. The rapid excretion of BP in urine was driven by elevated blood concentrations and its elimination reached about 90% within 120 min. In the very early period, BP was taken up by the liver and kidney and gradually released back to the blood. BH4 administration caused a considerable decrease in the BH4% in blood BP as an inevitable compensatory process. Probenecid treatment slowed down the decrease in blood BP and simultaneously inhibited its initial rapid excretion in the kidney. At the same time, the BH4% was further lowered, suggesting that the probenecid-sensitive BP uptake played a crucial role in BH2 scavenging in vivo. This suggested that the overproduced BH2 was taken up by organs by means of the probenecid-sensitive process, and was then scavenged by counter-conversion to BH4 via the BH4 salvage pathway. Taken together, BH4 administration was effective at raising BP levels in organs over the course of hours but with extremely low efficiency. Since a high BH2 relative to BH4 causes NOS dysfunction, the lowering of the BH4% must be avoided in practice, otherwise the desired effect of the supplementation in ameliorating NOS dysfunction would be spoiled.
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Affiliation(s)
- Akiko Ohashi
- Department of Anatomy, Nihon University School of Dentistry, Chiyoda, Tokyo, Japan
| | - Yusuke Saeki
- Department of Biosciences, Teikyo University of Science and TechnologyUenohara, Yamanashi, Japan
| | - Tomonori Harada
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo, Japan
| | - Masako Naito
- Department of Anatomy, Nihon University School of Dentistry, Chiyoda, Tokyo, Japan
| | - Tomihisa Takahashi
- Department of Anatomy, Nihon University School of Dentistry, Chiyoda, Tokyo, Japan
| | - Shin Aizawa
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo, Japan
| | - Hiroyuki Hasegawa
- Department of Anatomy, Nihon University School of Dentistry, Chiyoda, Tokyo, Japan
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo, Japan
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19
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Sethumadhavan S, Whitsett J, Bennett B, Ionova IA, Pieper GM, Vasquez-Vivar J. Increasing tetrahydrobiopterin in cardiomyocytes adversely affects cardiac redox state and mitochondrial function independently of changes in NO production. Free Radic Biol Med 2016; 93:1-11. [PMID: 26826575 PMCID: PMC5498285 DOI: 10.1016/j.freeradbiomed.2016.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/31/2015] [Accepted: 01/25/2016] [Indexed: 02/07/2023]
Abstract
Tetrahydrobiopterin (BH4) represents a potential strategy for the treatment of cardiac remodeling, fibrosis and/or diastolic dysfunction. The effects of oral treatment with BH4 (Sapropterin™ or Kuvan™) are however dose-limiting with high dose negating functional improvements. Cardiomyocyte-specific overexpression of GTP cyclohydrolase I (mGCH) increases BH4 several-fold in the heart. Using this model, we aimed to establish the cardiomyocyte-specific responses to high levels of BH4. Quantification of BH4 and BH2 in mGCH transgenic hearts showed age-based variations in BH4:BH2 ratios. Hearts of mice (<6 months) have lower BH4:BH2 ratios than hearts of older mice while both GTPCH activity and tissue ascorbate levels were higher in hearts of young than older mice. No evident changes in nitric oxide (NO) production assessed by nitrite and endogenous iron-nitrosyl complexes were detected in any of the age groups. Increased BH4 production in cardiomyocytes resulted in a significant loss of mitochondrial function. Diminished oxygen consumption and reserve capacity was verified in mitochondria isolated from hearts of 12-month old compared to 3-month old mice, even though at 12 months an improved BH4:BH2 ratio is established. Accumulation of 4-hydroxynonenal (4-HNE) and decreased glutathione levels were found in the mGCH hearts and isolated mitochondria. Taken together, our results indicate that the ratio of BH4:BH2 does not predict changes in neither NO levels nor cellular redox state in the heart. The BH4 oxidation essentially limits the capacity of cardiomyocytes to reduce oxidant stress. Cardiomyocyte with chronically high levels of BH4 show a significant decline in redox state and mitochondrial function.
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Affiliation(s)
- Savitha Sethumadhavan
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Jennifer Whitsett
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Brian Bennett
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA; Department of Physics, Marquette University, Milwaukee, 1250 W Wisconsin Ave, Milwaukee, WI 53233, USA
| | - Irina A Ionova
- Department of Surgery Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Galen M Pieper
- Department of Surgery Medicine, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Jeannette Vasquez-Vivar
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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20
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Hashimoto T, Sivakumaran V, Carnicer R, Zhu G, Hahn VS, Bedja D, Recalde A, Duglan D, Channon KM, Casadei B, Kass DA. Tetrahydrobiopterin Protects Against Hypertrophic Heart Disease Independent of Myocardial Nitric Oxide Synthase Coupling. J Am Heart Assoc 2016; 5:e003208. [PMID: 27001967 PMCID: PMC4943286 DOI: 10.1161/jaha.116.003208] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/11/2016] [Indexed: 01/09/2023]
Abstract
BACKGROUND Nitric oxide synthase uncoupling occurs under conditions of oxidative stress modifying the enzyme's function so it generates superoxide rather than nitric oxide. Nitric oxide synthase uncoupling occurs with chronic pressure overload, and both are ameliorated by exogenous tetrahydrobiopterin (BH4)-a cofactor required for normal nitric oxide synthase function-supporting a pathophysiological link. Genetically augmenting BH4 synthesis in endothelial cells fails to replicate this benefit, indicating that other cell types dominate the effects of exogenous BH4 administration. We tested whether the primary cellular target of BH4 is the cardiomyocyte or whether other novel mechanisms are invoked. METHODS AND RESULTS Mice with cardiomyocyte-specific overexpression of GTP cyclohydrolase 1 (mGCH1) and wild-type littermates underwent transverse aortic constriction. The mGCH1 mice had markedly increased myocardial BH4 and, unlike wild type, maintained nitric oxide synthase coupling after transverse aortic constriction; however, the transverse aortic constriction-induced abnormalities in cardiac morphology and function were similar in both groups. In contrast, exogenous BH4 supplementation improved transverse aortic constricted hearts in both groups, suppressed multiple inflammatory cytokines, and attenuated infiltration of inflammatory macrophages into the heart early after transverse aortic constriction. CONCLUSIONS BH4 protection against adverse remodeling in hypertrophic cardiac disease is not driven by its prevention of myocardial nitric oxide synthase uncoupling, as presumed previously. Instead, benefits from exogenous BH4 are mediated by a protective effect coupled to suppression of inflammatory pathways and myocardial macrophage infiltration.
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MESH Headings
- Animals
- Anti-Inflammatory Agents/pharmacology
- Biopterins/analogs & derivatives
- Biopterins/pharmacology
- Cardiovascular Agents/pharmacology
- Cytokines/metabolism
- Cytoprotection
- Disease Models, Animal
- GTP Cyclohydrolase/genetics
- GTP Cyclohydrolase/metabolism
- Humans
- Hypertrophy, Left Ventricular/enzymology
- Hypertrophy, Left Ventricular/pathology
- Hypertrophy, Left Ventricular/physiopathology
- Hypertrophy, Left Ventricular/prevention & control
- Inflammation Mediators/metabolism
- Macrophages/drug effects
- Macrophages/metabolism
- Mice, Transgenic
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Nitric Oxide/metabolism
- Nitric Oxide Synthase/metabolism
- Oxidation-Reduction
- Signal Transduction
- Superoxides/metabolism
- Time Factors
- Ventricular Dysfunction, Left/enzymology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Dysfunction, Left/prevention & control
- Ventricular Function, Left/drug effects
- Ventricular Remodeling/drug effects
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Affiliation(s)
- Toru Hashimoto
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Vidhya Sivakumaran
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | | | - Guangshuo Zhu
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Virginia S Hahn
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Djahida Bedja
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
| | - Alice Recalde
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - Drew Duglan
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - Keith M Channon
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - Barbara Casadei
- Department of Cardiovascular Medicine, University of Oxford, UK
| | - David A Kass
- Division of Cardiology, Johns Hopkins Medical Institutions, Baltimore, MD
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21
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Loer CM, Calvo AC, Watschinger K, Werner-Felmayer G, O'Rourke D, Stroud D, Tong A, Gotenstein JR, Chisholm AD, Hodgkin J, Werner ER, Martinez A. Cuticle integrity and biogenic amine synthesis in Caenorhabditis elegans require the cofactor tetrahydrobiopterin (BH4). Genetics 2015; 200:237-53. [PMID: 25808955 PMCID: PMC4423366 DOI: 10.1534/genetics.114.174110] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 03/12/2015] [Indexed: 11/18/2022] Open
Abstract
Tetrahydrobiopterin (BH4) is the natural cofactor of several enzymes widely distributed among eukaryotes, including aromatic amino acid hydroxylases (AAAHs), nitric oxide synthases (NOSs), and alkylglycerol monooxygenase (AGMO). We show here that the nematode Caenorhabditis elegans, which has three AAAH genes and one AGMO gene, contains BH4 and has genes that function in BH4 synthesis and regeneration. Knockout mutants for putative BH4 synthetic enzyme genes lack the predicted enzymatic activities, synthesize no BH4, and have indistinguishable behavioral and neurotransmitter phenotypes, including serotonin and dopamine deficiency. The BH4 regeneration enzymes are not required for steady-state levels of biogenic amines, but become rate limiting in conditions of reduced BH4 synthesis. BH4-deficient mutants also have a fragile cuticle and are generally hypersensitive to exogenous agents, a phenotype that is not due to AAAH deficiency, but rather to dysfunction in the lipid metabolic enzyme AGMO, which is expressed in the epidermis. Loss of AGMO or BH4 synthesis also specifically alters the sensitivity of C. elegans to bacterial pathogens, revealing a cuticular function for AGMO-dependent lipid metabolism in host-pathogen interactions.
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Affiliation(s)
- Curtis M Loer
- Department of Biology, University of San Diego, San Diego, California, 92110
| | - Ana C Calvo
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
| | - Katrin Watschinger
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Gabriele Werner-Felmayer
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Delia O'Rourke
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Dave Stroud
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Amy Tong
- Division of Biological Sciences, University of California, San Diego, California 92093
| | - Jennifer R Gotenstein
- Division of Biological Sciences, University of California, San Diego, California 92093
| | - Andrew D Chisholm
- Division of Biological Sciences, University of California, San Diego, California 92093
| | - Jonathan Hodgkin
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Ernst R Werner
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, 5009 Bergen, Norway
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22
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Longo N, Arnold GL, Pridjian G, Enns GM, Ficicioglu C, Parker S, Cohen-Pfeffer JL. Long-term safety and efficacy of sapropterin: the PKUDOS registry experience. Mol Genet Metab 2015; 114:557-63. [PMID: 25724073 DOI: 10.1016/j.ymgme.2015.02.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/10/2015] [Accepted: 02/10/2015] [Indexed: 11/26/2022]
Abstract
The Phenylketonuria (PKU) Demographics, Outcomes and Safety (PKUDOS) registry is designed to provide longitudinal safety and efficacy data on subjects with PKU who are (or have been) treated with sapropterin dihydrochloride. The PKUDOS population consists of 1189 subjects with PKU: N = 504 who were continuously exposed to sapropterin from date of registry enrollment, N = 211 who had intermittent exposure to the drug, and N = 474 with some other duration of exposure. Subjects continuously exposed to sapropterin showed an average 34% decrease in blood phenylalanine (Phe)--from 591 ± 382 μmol/L at baseline to 392 ± 239 μmol/L (p = 0.0009) after 5 years. This drop in blood Phe was associated with an increase in dietary Phe tolerance [from 1000 ± 959 mg/day (pre-sapropterin baseline) to 1539 ± 840 mg/day after 6 years]. Drug-related adverse events (AEs) were reported in 6% of subjects, were mostly considered non-serious, and were identified in the gastrointestinal, respiratory, and nervous systems. Serious drug-related AEs were reported in ≤ 1% of subjects. Similar safety and efficacy data were observed for children<4 years. Long-term data from the PKUDOS registry suggest that sapropterin has a tolerable safety profile and that continuous use is associated with a significant and persistent decrease in blood Phe and improvements in dietary Phe tolerance.
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Affiliation(s)
- Nicola Longo
- University of Utah, Division of Medical Genetics, Salt Lake City, UT 84108, USA
| | - Georgianne L Arnold
- University of Pittsburgh School of Medicine, Department of Pediatrics, Children's Hospital of Pittsburgh, Pittsburgh, PA 15238, USA
| | - Gabriella Pridjian
- Tulane University School of Medicine, Hayward Genetics Center, New Orleans, LA 70112, USA
| | - Gregory M Enns
- Stanford University, Division of Medical Genetics, Stanford, CA 94305-5208, USA
| | - Can Ficicioglu
- The Children's Hospital of Philadelphia, Perelman School of Medicine,University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Susan Parker
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
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23
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Hofmeister LH, Lee SH, Norlander AE, Montaniel KRC, Chen W, Harrison DG, Sung HJ. Phage-display-guided nanocarrier targeting to atheroprone vasculature. ACS NANO 2015; 9:4435-46. [PMID: 25768046 PMCID: PMC4654777 DOI: 10.1021/acsnano.5b01048] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In regions of the circulation where vessels are straight and unbranched, blood flow is laminar and unidirectional. In contrast, at sites of curvature, branch points, and regions distal to stenoses, blood flow becomes disturbed. Atherosclerosis preferentially develops in these regions of disturbed blood flow. Current therapies for atherosclerosis are systemic and may not sufficiently target these atheroprone regions. In this study, we sought to leverage the alterations on the luminal surface of endothelial cells caused by this atheroprone flow for nanocarrier targeting. In vivo phage display was used to discover unique peptides that selectively bind to atheroprone regions in the mouse partial carotid artery ligation model. The peptide GSPREYTSYMPH (PREY) was found to bind 4.5-fold more avidly to the region of disturbed flow and was used to form targeted liposomes. When administered intravenously, PREY-targeted liposomes preferentially accumulated in endothelial cells in the partially occluded carotid artery and other areas of disturbed flow. Proteomic analysis and immunoblotting indicated that fibronectin and Filamin-A were preferentially bound by PREY nanocarriers in vessels with disturbed flow. In additional experiments, PREY nanocarriers were used therapeutically to deliver the nitric oxide synthase cofactor tetrahydrobiopterin (BH4), which we have previously shown to be deficient in regions of disturbed flow. This intervention increased vascular BH4 and reduced vascular superoxide in the partially ligated artery in wild-type mice and reduced plaque burden in the partially ligated left carotid artery of fat fed atheroprone mice (ApoE(-/-)). Targeting atheroprone sites of the circulation with functionalized nanocarriers provides a promising approach for prevention of early atherosclerotic lesion formation.
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Affiliation(s)
- Lucas H. Hofmeister
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235
| | - Sue H. Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235
| | | | | | - Wei Chen
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, 37235
| | - David G. Harrison
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, 37235
- Center for Vascular Biology, Vanderbilt University, Nashville, TN, 37235
- Division of Cardiovascular Medicine, Vanderbilt University, Nashville, TN, 37235
| | - Hak-Joon Sung
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235
- Division of Cardiovascular Medicine, Vanderbilt University, Nashville, TN, 37235
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24
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Sapropterin Dihydrochloride Mixed With Common Foods and Beverages. TOP CLIN NUTR 2014; 29:325-331. [PMID: 25382934 PMCID: PMC4213132 DOI: 10.1097/tin.0000000000000010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Sapropterin dihydrochloride is used to lower blood phenylalanine levels in tetrahydrobiopterin-responsive phenylketonuria in conjunction with a phenylalanine-restricted diet. This study investigated the solubility and stability of sapropterin tablets and a sapropterin powder formulation when mixed in selected beverages and foods. Solubility was partial for the tablets and complete for the powder. The stability testing showed that 93% or more of active sapropterin dihydrochloride is present at 1 hour after either tablets or powders are mixed with certain foods and beverages. Mixing sapropterin powder with foods and beverages might facilitate its administration in patients who have difficulty swallowing the drug according to prescribing information.
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25
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Schmidt K, Kolesnik B, Gorren ACF, Werner ER, Mayer B. Cell type-specific recycling of tetrahydrobiopterin by dihydrofolate reductase explains differential effects of 7,8-dihydrobiopterin on endothelial nitric oxide synthase uncoupling. Biochem Pharmacol 2014; 90:246-53. [PMID: 24863258 PMCID: PMC4099517 DOI: 10.1016/j.bcp.2014.05.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 05/14/2014] [Accepted: 05/14/2014] [Indexed: 11/26/2022]
Abstract
(6R)-5,6,7,8-Tetrahydro-L-biopterin (BH4) availability regulates nitric oxide and superoxide formation by endothelial nitric oxide synthase (eNOS). At low BH4 or low BH4 to 7,8-dihydrobiopterin (BH2) ratios the enzyme becomes uncoupled and generates superoxide at the expense of NO. We studied the effects of exogenously added BH2 on intracellular BH4/BH2 ratios and eNOS activity in different types of endothelial cells. Incubation of porcine aortic endothelial cells with BH2 increased BH4/BH2 ratios from 8.4 (controls) and 0.5 (BH4-depleted cells) up to ~20, demonstrating efficient reduction of BH2. Uncoupled eNOS activity observed in BH4-depleted cells was prevented by preincubation with BH2. Recycling of BH4 was much less efficient in human endothelial cells isolated from umbilical veins or derived from dermal microvessels (HMEC-1 cells), which exhibited eNOS uncoupling and low BH4/BH2 ratios under basal conditions and responded to exogenous BH2 with only moderate increases in BH4/BH2 ratios. The kinetics of dihydrofolate reductase-catalyzed BH4 recycling in endothelial cytosols showed that the apparent BH2 affinity of the enzyme was 50- to 300-fold higher in porcine than in human cell preparations. Thus, the differential regulation of eNOS uncoupling in different types of endothelial cells may be explained by striking differences in the apparent BH2 affinity of dihydrofolate reductase.
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Affiliation(s)
- Kurt Schmidt
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria.
| | - Bernd Kolesnik
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
| | - Antonius C F Gorren
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
| | - Ernst R Werner
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, A-6020 Innsbruck, Austria
| | - Bernd Mayer
- Department of Pharmacology and Toxicology, Karl-Franzens-Universität Graz, A-8010 Graz, Austria
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26
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Carnicer R, Hale AB, Suffredini S, Liu X, Reilly S, Zhang MH, Surdo NC, Bendall JK, Crabtree MJ, Lim GBS, Alp NJ, Channon KM, Casadei B. Cardiomyocyte GTP cyclohydrolase 1 and tetrahydrobiopterin increase NOS1 activity and accelerate myocardial relaxation. Circ Res 2012; 111:718-27. [PMID: 22798524 DOI: 10.1161/circresaha.112.274464] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Tetrahydrobiopterin (BH4) is an essential cofactor of nitric oxide synthases (NOS). Oral BH4 supplementation preserves cardiac function in animal models of cardiac disease; however, the mechanisms underlying these findings are not completely understood. OBJECTIVE To study the effect of myocardial transgenic overexpression of the rate-limiting enzyme in BH4 biosynthesis, GTP cyclohydrolase 1 (GCH1), on NOS activity, myocardial function, and Ca2+ handling. METHODS AND RESULTS GCH1overexpression significantly increased the biopterins level in left ventricular (LV) myocytes but not in the nonmyocyte component of the LV myocardium or in plasma. The ratio between BH4 and its oxidized products was lower in mGCH1-Tg, indicating that a large proportion of the myocardial biopterin pool was oxidized; nevertheless, myocardial NOS1 activity was increased in mGCH1-Tg, and superoxide release was significantly reduced. Isolated hearts and field-stimulated LV myocytes (3 Hz, 35°C) overexpressing GCH1 showed a faster relaxation and a PKA-mediated increase in the PLB Ser16 phosphorylated fraction and in the rate of decay of the [Ca2+]i transient. RyR2 S-nitrosylation and diastolic Ca2+ leak were larger in mGCH1-Tg and ICa density was lower; nevertheless the amplitude of the [Ca2+]i transient and contraction did not differ between genotypes, because of an increase in the SR fractional release of Ca2+ in mGCH1-Tg myocytes. Xanthine oxidoreductase inhibition abolished the difference in superoxide production but did not affect myocardial function in either group. By contrast, NOS1 inhibition abolished the differences in ICa density, Ser16 PLB phosphorylation, [Ca2+]i decay, and myocardial relaxation between genotypes. CONCLUSIONS Myocardial GCH1 activity and intracellular BH4 are a limiting factor for constitutive NOS1 and SERCA2A activity in the healthy myocardium. Our findings suggest that GCH1 may be a valuable target for the treatment of LV diastolic dysfunction.
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Affiliation(s)
- Ricardo Carnicer
- Department of Cardiovascular Medicine, University of Oxford, Level 6, West Wing, John Radcliffe Hospital, OX3 9DU, United Kingdom
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27
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Ohashi A, Suetake Y, Saeki Y, Harada T, Aizawa S, Hasegawa H. Rapid clearance of supplemented tetrahydrobiopterin is driven by high-capacity transporters in the kidney. Mol Genet Metab 2012; 105:575-81. [PMID: 22318121 DOI: 10.1016/j.ymgme.2012.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/11/2012] [Accepted: 01/11/2012] [Indexed: 11/17/2022]
Abstract
Tetrahydrobiopterin (BH(4)) is an essential cofactor of aromatic amino acid hydroxylases and NO synthase. Supplementation of BH(4) potentially targets cardiovascular dysfunction as well as inherited BH(4) deficiencies and BH(4)-responsive phenylketonuria. However, the high cost/effect ratio of the recommended daily dose of BH(4) supplementation acts against further popularization of this therapy. The aim of this study was to attenuate urinary excretion with the intention of improving efficacy of BH(4) supplementation. The rapid excretion of BH(4) in the urine was confirmed to be the major route of supplemented BH(4) loss. In addition to glomerular filtration into the urine, a dominant rapid exclusion by renal secretion was observed in rats (T((1/2))=16 min) when the plasma BH(4) was higher than about 1 nmol/mL (more than 10 times higher than normal), due to BH(4) supplementation. The rapidity of the process was slowed by prior administration of cyclosporin A, a representative anti-excretory drug, and the excretion decelerated to a moderate rate (T((1/2))=53 min). By the combined administration of BH(4) plus cyclosporin A, the blood BH(4) levels were dramatically elevated. It was hypothesized that the drug interfered with kidney excretion of BH(4) rather than by attenuating organ tissue distribution by inhibiting biopterin uptake from the plasma. Consistent with this hypothesis, biopterin levels after BH(4) administration were elevated in major organs in the presence of anti-excretory drugs without notable change in their BH(4) fraction which was consistently 95% or higher regardless of combined administration with the drugs. Targeting these putative transporters would be a promising approach for improving the efficiency of BH(4) supplementation therapy.
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Affiliation(s)
- Akiko Ohashi
- Division of Anatomical Science, Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo 173-8610, Japan
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28
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Wang H, Yang B, Hao G, Feng Y, Chen H, Feng L, Zhao J, Zhang H, Chen YQ, Wang L, Chen W. Biochemical characterization of the tetrahydrobiopterin synthesis pathway in the oleaginous fungus Mortierella alpina. MICROBIOLOGY (READING, ENGLAND) 2011; 157:3059-3070. [PMID: 21852350 PMCID: PMC4811656 DOI: 10.1099/mic.0.051847-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 08/10/2011] [Accepted: 08/17/2011] [Indexed: 11/18/2022]
Abstract
We characterized the de novo biosynthetic pathway of tetrahydrobiopterin (BH₄) in the lipid-producing fungus Mortierella alpina. The BH₄ cofactor is essential for various cell processes, and is probably present in every cell or tissue of higher organisms. Genes encoding two copies of GTP cyclohydrolase I (GTPCH-1 and GTPCH-2) for the conversion of GTP to dihydroneopterin triphosphate (H₂-NTP), 6-pyruvoyltetrahydropterin synthase (PTPS) for the conversion of H₂-NTP to 6-pyruvoyltetrahydropterin (PPH₄), and sepiapterin reductase (SR) for the conversion of PPH₄ to BH₄, were expressed heterologously in Escherichia coli. The recombinant enzymes were produced as His-tagged fusion proteins and were purified to homogeneity to investigate their enzymic activities. Enzyme products were analysed by HPLC and electrospray ionization-MS. Kinetic parameters and other properties of GTPCH, PTPS and SR were investigated. Physiological roles of BH₄ in M. alpina are discussed, and comparative analyses between GTPCH, PTPS and SR proteins and other homologous proteins were performed. The presence of two functional GTPCH enzymes has, as far as we are aware, not been reported previously, reflecting the unique ability of this fungus to synthesize both BH₄ and folate, using the GTPCH product as a common substrate. To our knowledge, this study is the first to report the comprehensive characterization of a BH₄ biosynthesis pathway in a fungus.
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Affiliation(s)
- Hongchao Wang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Bo Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Guangfei Hao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Yun Feng
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin Economic-Technological Development Area, Tianjin 300457, PR China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Lu Feng
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin Economic-Technological Development Area, Tianjin 300457, PR China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Yong Q. Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
| | - Lei Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin Economic-Technological Development Area, Tianjin 300457, PR China
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China
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29
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Moens AL, Kietadisorn R, Lin JY, Kass D. Targeting endothelial and myocardial dysfunction with tetrahydrobiopterin. J Mol Cell Cardiol 2011; 51:559-63. [PMID: 21458460 DOI: 10.1016/j.yjmcc.2011.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 03/11/2011] [Accepted: 03/16/2011] [Indexed: 11/24/2022]
Abstract
Tetrahydrobiopterin (BH(4)) is an essential cofactor for aromatic amino acid hydroxylases and for all three nitric oxide synthase (NOS) isoforms. It also has a protective role in the cell as an antioxidant and scavenger of reactive nitrogen and oxygen species. Experimental studies in humans and animals demonstrate that decreased BH(4)-bioavailability, with subsequent uncoupling of endothelial NOS (eNOS) plays an important role in the pathogenesis of endothelial dysfunction, hypertension, ischemia-reperfusion injury, and pathologic cardiac remodeling. Synthetic BH(4) is clinically approved for the treatment of phenylketonuria, and experimental studies support its capacity for ameliorating cardiovascular pathophysiologies. To date, however, the translation of these studies to human patients remains limited, and early results have been mixed. In this review, we discuss the pathophysiologic role of decreased BH(4) bioavailability, molecular mechanisms regulating its metabolism, and its potential therapeutic use as well as pitfalls as an NOS-modulating drug. This article is part of a special issue entitled ''Key Signaling Molecules in Hypertrophy and Heart Failure.''
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Affiliation(s)
- An L Moens
- Maastricht University Medical Centre, Cardiovascular Research Institute Maastricht, Dept. of Cardiology, Maastricht, The Netherlands.
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30
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Abstract
Understanding and consequently treating neuropathic pain effectively is a challenge for modern medicine, as unlike inflammation, which can be controlled relatively well, chronic pain due to nerve injury is refractory to most current therapeutics. Here we define a target pathway for a new class of analgesics, tetrahydrobiopterin (BH4) synthesis and metabolism. BH4 is an essential co-factor in the synthesis of serotonin, dopamine, epinephrine, norepinephrine and nitric oxide and as a result, its availability influences many systems, including neurons. Following peripheral nerve damage, levels of BH4 are dramatically increased in sensory neurons, consequently this has a profound effect on the physiology of these cells, causing increased activity and pain hypersensitivity. These changes are principally due to the upregulation of the rate limiting enzyme for BH4 synthesis GTP Cyclohydrolase 1 (GCH1). A GCH1 pain-protective haplotype which decreases pain levels in a variety of settings, by reducing the levels of endogenous activation of this enzyme, has been characterized in humans. Here we define the control of BH4 homeostasis and discuss the consequences of large perturbations within this system, both negatively via genetic mutations and after pathological increases in the production of this cofactor that result in chronic pain. We explain the nature of the GCH1 reduced-function haplotype and set out the potential for a ' BH4 blocking' drug as a novel analgesic.
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Affiliation(s)
- Alban Latremoliere
- F.M. Kirby Neurobiology Center, Children’s Hospital Boston, Harvard Medical School, 3 Blackfan Circle, CLS 12260, Boston, MA 02115, USA
| | - Michael Costigan
- F.M. Kirby Neurobiology Center, Children’s Hospital Boston, Harvard Medical School, 3 Blackfan Circle, CLS 12260, Boston, MA 02115, USA
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31
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Abstract
BH4 (6R-L-erythro-5,6,7,8-tetrahydrobiopterin) is an essential cofactor of a set of enzymes that are of central metabolic importance, including four aromatic amino acid hydroxylases, alkylglycerol mono-oxygenase and three NOS (NO synthase) isoenzymes. Consequently, BH4 is present in probably every cell or tissue of higher organisms and plays a key role in a number of biological processes and pathological states associated with monoamine neurotransmitter formation, cardiovascular and endothelial dysfunction, the immune response and pain sensitivity. BH4 is formed de novo from GTP via a sequence of three enzymatic steps carried out by GTP cyclohydrolase I, 6-pyruvoyltetrahydropterin synthase and sepiapterin reductase. An alternative or salvage pathway involves dihydrofolate reductase and may play an essential role in peripheral tissues. Cofactor regeneration requires pterin-4a-carbinolamine dehydratase and dihydropteridine reductase, except for NOSs, in which the BH4 cofactor undergoes a one-electron redox cycle without the need for additional regeneration enzymes. With regard to the regulation of cofactor biosynthesis, the major controlling point is GTP cyclohydrolase I. BH4 biosynthesis is controlled in mammals by hormones and cytokines. BH4 deficiency due to autosomal recessive mutations in all enzymes, except for sepiapterin reductase, has been described as a cause of hyperphenylalaninaemia. A major contributor to vascular dysfunction associated with hypertension, ischaemic reperfusion injury, diabetes and others, appears to be an effect of oxidized BH4, which leads to an increased formation of oxygen-derived radicals instead of NO by decoupled NOS. Furthermore, several neurological diseases have been suggested to be a consequence of restricted cofactor availability, and oral cofactor replacement therapy to stabilize mutant phenylalanine hydroxylase in the BH4-responsive type of hyperphenylalaninaemia has an advantageous effect on pathological phenylalanine levels in patients.
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Affiliation(s)
- Ernst R Werner
- Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck A-6020, Austria
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Teng RJ, Du J, Xu H, Bakhutashvili I, Eis A, Shi Y, Pritchard KA, Konduri GG. Sepiapterin improves angiogenesis of pulmonary artery endothelial cells with in utero pulmonary hypertension by recoupling endothelial nitric oxide synthase. Am J Physiol Lung Cell Mol Physiol 2011; 301:L334-45. [PMID: 21622842 PMCID: PMC3174740 DOI: 10.1152/ajplung.00316.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 05/23/2011] [Indexed: 02/07/2023] Open
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) is associated with decreased blood vessel density that contributes to increased pulmonary vascular resistance. Previous studies showed that uncoupled endothelial nitric oxide (NO) synthase (eNOS) activity and increased NADPH oxidase activity resulted in marked decreases in NO bioavailability and impaired angiogenesis in PPHN. In the present study, we hypothesize that loss of tetrahydrobiopterin (BH4), a critical cofactor for eNOS, induces uncoupled eNOS activity and impairs angiogenesis in PPHN. Pulmonary artery endothelial cells (PAEC) isolated from fetal lambs with PPHN (HTFL-PAEC) or control lambs (NFL-PAEC) were used to investigate the cellular mechanisms impairing angiogenesis in PPHN. Cellular mechanisms were examined with respect to BH4 levels, GTP-cyclohydrolase-1 (GCH-1) expression, eNOS dimer formation, and eNOS-heat shock protein 90 (hsp90) interactions under basal conditions and after sepiapterin (Sep) supplementation. Cellular levels of BH4, GCH-1 expression, and eNOS dimer formation were decreased in HTFL-PAEC compared with NFL-PAEC. Sep supplementation decreased apoptosis and increased in vitro angiogenesis in HTFL-PAEC and ex vivo pulmonary artery sprouting angiogenesis. Sep also increased cellular BH4 content, NO production, eNOS dimer formation, and eNOS-hsp90 association and decreased the superoxide formation in HTFL-PAEC. These data demonstrate that Sep improves NO production and angiogenic potential of HTFL-PAEC by recoupling eNOS activity. Increasing BH4 levels via Sep supplementation may be an important therapy for improving eNOS function and restoring angiogenesis in PPHN.
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Affiliation(s)
- Ru-Jeng Teng
- Division of Neonatology, Dept. of Pediatrics, Medical College of Wisconsin, Suite C410, Children Corporate Center, 999N 92nd St., Wauwatosa, WI 53226, USA.
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Role of Sepiapterin on Endothelial Nitric Oxide Synthase in Acute Kidney Injury: An Enigmatic Story. J Cardiovasc Pharmacol 2011. [DOI: 10.1097/fjc.0b013e31822ba6a4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Legrand M, Kandil A, Payen D, Ince C. Effects of sepiapterin infusion on renal oxygenation and early acute renal injury after suprarenal aortic clamping in rats. J Cardiovasc Pharmacol 2011; 58:192-8. [PMID: 21562427 DOI: 10.1097/fjc.0b013e31821f8ec3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Acute kidney injury (AKI) can occur after aortic clamping due to microvascular dysfunction leading to renal hypoxia. In this rat study, we have tested the hypothesis that the administration of the precursor of the nitric oxide synthase essential cofactor tetrahydrobiopterin (BH4) could restore renal oxygenation after ischemia reperfusion (I/R) and prevent AKI. We randomly distributed rats into 4 groups: sham group; ischemia-reperfusion group; I/R + sepiapterin, the precursor of BH4; and I/R + sepiapterin + methotrexate, an inhibitor of the pathway generating BH4 from sepiapterin. Cortical and outer medullary microvascular oxygen pressure, renal oxygen delivery, renal oxygen consumption were measured using dual-wavelength oxygen-dependent quenching phosphorescence techniques during ischemia and throughout 3 hours of reperfusion. Kidney injury was assessed using myeloperoxidase staining for leukocyte infiltration and urine neutrophil gelatinase-associated lipocalin levels. Ischemia reperfusion induced a drop in microvascular PO2 (P < 0.01 vs. Sham, both), which was prevented by the infusion of sepiapterin. Sepiapterin partially prevented the rise in renal oxygen extraction (P < 0.001 vs. I/R). Finally, treatment with sepiapterin prevented renal infiltration by inflammatory cells and decreased urine neutrophil gelatinase-associated lipocalin levels indicating a decrease of renal injury. These effects were blunted when adding methotrexate, except for myeloperoxidase. In conclusion, the administration of sepiapterin can prevent renal hypoxia and AKI after suprarenal aortic clamping in rats.
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Affiliation(s)
- Matthieu Legrand
- Department of Translational Physiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Dabrowska M, Skoneczny M, Rode W. Functional gene expression profile underlying methotrexate-induced senescence in human colon cancer cells. Tumour Biol 2011; 32:965-76. [PMID: 21678067 PMCID: PMC3156317 DOI: 10.1007/s13277-011-0198-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 05/27/2011] [Indexed: 11/21/2022] Open
Abstract
Cellular functions accompanying establishment of premature senescence in methotrexate-treated human colon cancer C85 cells are deciphered in the present study from validated competitive expression microarray data, analyzed with the use of Ingenuity Pathways Analysis (IPA) software. The nitrosative/oxidative stress, inferred from upregulated expression of inducible nitric oxide synthase (iNOS) and mitochondrial dysfunction-associated genes, including monoamine oxidases MAOA and MAOB, β-amyloid precursor protein (APP) and presenilin 1 (PSEN1), is identified as the main determinant of signaling pathways operating during senescence establishment. Activation of p53-signaling pathway is found associated with both apoptotic and autophagic components contributing to this process. Activation of nuclear factor κB (NF-κB), resulting from interferon γ (IFNγ), integrin, interleukin 1β (IL-1β), IL-4, IL-13, IL-22, Toll-like receptors (TLRs) 1, 2 and 3, growth factors and tumor necrosis factor (TNF) superfamily members signaling, is found to underpin inflammatory properties of senescent C85 cells. Upregulation of p21-activated kinases (PAK2 and PAK6), several Rho molecules and myosin regulatory light chains MYL12A and MYL12B, indicates acquisition of motility by those cells. Mitogen-activated protein kinase p38 MAPK β, extracellular signal-regulated kinases ERK2 and ERK5, protein kinase B AKT1, as well as calcium, are identified as factors coordinating signaling pathways in senescent C85 cells.
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Affiliation(s)
- Magdalena Dabrowska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093, Warsaw, Poland.
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Zhang Y, Janssens SP, Wingler K, Schmidt HHHW, Moens AL. Modulating endothelial nitric oxide synthase: a new cardiovascular therapeutic strategy. Am J Physiol Heart Circ Physiol 2011; 301:H634-46. [PMID: 21622818 DOI: 10.1152/ajpheart.01315.2010] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The pathogenesis of many cardiovascular diseases is associated with reduced nitric oxide (NO) bioavailability and/or increased endothelial NO synthase (eNOS)-dependent superoxide formation. These findings support that restoring and conserving adequate NO signaling in the heart and blood vessels is a promising therapeutic intervention. In particular, modulating eNOS, e.g., through increasing the bioavailability of its substrate and cofactors, enhancing its transcription, and interfering with other modulators of eNOS pathway, such as netrin-1, has a high potential for effective treatments of cardiovascular diseases. This review provides an overview of the possibilities for modulating eNOS and how this may be translated to the clinic in addition to describing the genetic models used to study eNOS modulation.
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Affiliation(s)
- Yixuan Zhang
- Department of Cardiology, Maastricht University Medical Centre, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
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Rakovich T, Boland C, Bernstein I, Chikwana VM, Iwata-Reuyl D, Kelly VP. Queuosine deficiency in eukaryotes compromises tyrosine production through increased tetrahydrobiopterin oxidation. J Biol Chem 2011; 286:19354-63. [PMID: 21487017 DOI: 10.1074/jbc.m111.219576] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Queuosine is a modified pyrrolopyrimidine nucleoside found in the anticodon loop of transfer RNA acceptors for the amino acids tyrosine, asparagine, aspartic acid, and histidine. Because it is exclusively synthesized by bacteria, higher eukaryotes must salvage queuosine or its nucleobase queuine from food and the gut microflora. Previously, animals made deficient in queuine died within 18 days of withdrawing tyrosine, a nonessential amino acid, from the diet (Marks, T., and Farkas, W. R. (1997) Biochem. Biophys. Res. Commun. 230, 233-237). Here, we show that human HepG2 cells deficient in queuine and mice made deficient in queuosine-modified transfer RNA, by disruption of the tRNA guanine transglycosylase enzyme, are compromised in their ability to produce tyrosine from phenylalanine. This has similarities to the disease phenylketonuria, which arises from mutation in the enzyme phenylalanine hydroxylase or from a decrease in the supply of its cofactor tetrahydrobiopterin (BH4). Immunoblot and kinetic analysis of liver from tRNA guanine transglycosylase-deficient animals indicates normal expression and activity of phenylalanine hydroxylase. By contrast, BH4 levels are significantly decreased in the plasma, and both plasma and urine show a clear elevation in dihydrobiopterin, an oxidation product of BH4, despite normal activity of the salvage enzyme dihydrofolate reductase. Our data suggest that queuosine modification limits BH4 oxidation in vivo and thereby potentially impacts on numerous physiological processes in eukaryotes.
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Affiliation(s)
- Tatsiana Rakovich
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
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Ohashi A, Sugawara Y, Mamada K, Harada Y, Sumi T, Anzai N, Aizawa S, Hasegawa H. Membrane transport of sepiapterin and dihydrobiopterin by equilibrative nucleoside transporters: a plausible gateway for the salvage pathway of tetrahydrobiopterin biosynthesis. Mol Genet Metab 2011; 102:18-28. [PMID: 20956085 DOI: 10.1016/j.ymgme.2010.09.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 09/15/2010] [Accepted: 09/15/2010] [Indexed: 10/19/2022]
Abstract
Tetrahydrobiopterin (BH(4)) is synthesized de novo in particular cells, but in the case of a systemic or local BH(4) deficiency, BH(4) supplementation therapy is applied. BH(4)-responsive PKU has also been effectively treated with BH(4) supplementation. However, the rapid clearance of the supplemented BH(4) has prevented the therapy from being widely accepted. Deposition of BH(4) after supplementation involves oxidation of BH(4) to dihydrobiopterin (BH(2)) and subsequent conversion to BH(4) by the salvage pathway. This pathway is known to be almost ubiquitous in the body. However, the mechanism for the redistribution and exclusion of BH(4) across the plasma membrane remains unclear. The aim of this work was to search for the key transporter of the uptake precursor of the salvage pathway. Based on the observed sensitivity of pterin transport to nitrobenzylthioinosine (NBMPR), we examined the ability of ENT1 and ENT2, representative equilibrative nucleoside transporters, to transport sepiapterin (SP), BH(2) or BH(4) using HeLa cell and Xenopus oocyte expression systems. hENT2 was capable of transporting the pterins with an efficiency of SP>BH(2)>BH(4). hENT1 could also transport the pterins but less efficiently. Non-transfected HeLa cells and rat aortic endothelial cells were able to incorporate the pterins and accumulate BH(4) via uptake that is likely mediated by ENT2 (SP>BH(2)>BH(4)). When exogenous BH(2) was given to mice, it was efficiently converted to BH(4) and its tissue deposition was similar to that of sepiapterin as reported (Sawabe et al., 2004). BH(4) deposition after BH(2) administration was influenced by prior treatment with NBMPR, suggesting that the distribution of the administered BH(2) was largely mediated by ENT2, although urinary excretion appeared to be managed by other mechanisms. The molecular basis of the transport of SP, BH(2), and BH(4) across the plasma membrane has now been described for the first time: ENT2 is a transporter of these pterins and is a plausible gateway to the salvage pathway of BH(4) biosynthesis, at least under conditions of exogenous pterin supplementation. The significance of the gateway was discussed in terms of BH(2) uptake for BH(4) accumulation and the release for modifying the intracellular BH(2)/BH(4) ratio.
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Affiliation(s)
- Akiko Ohashi
- Department of Functional Morphology, Nihon University School of Medicine, Itabashi, Tokyo, 173-8610, Japan
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GANGULA PRR, MUKHOPADHYAY S, PASRICHA PJ, RAVELLA K. Sepiapterin reverses the changes in gastric nNOS dimerization and function in diabetic gastroparesis. Neurogastroenterol Motil 2010; 22:1325-31, e351-2. [PMID: 20731778 PMCID: PMC3072796 DOI: 10.1111/j.1365-2982.2010.01588.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND We have demonstrated previously that in vivo supplementation of tetrahydrobiopterin (BH₄); a co-factor for neuronal nitric oxide synthase (nNOS) significantly restored delayed gastric emptying and attenuated nitrergic relaxation in diabetic rat. In this study, we have investigated whether supplementation of sepiapterin (SEP), a precursor for BH₄ biosynthesis via salvage pathway restores gastric emptying and nitrergic system in female diabetic rats. METHODS Diabetic rats (streptozotocin-induced) were supplemented with BH₄ or SEP (20 mg kg⁻¹ body weight). Gastric nitrergic relaxation in the presence or absence of high glucose and SEP were measured by electric field stimulation. Gastric muscular strips from healthy or diabetic female rats were incubated in the presence or absence of high glucose, SEP and/or methotrexate (MTX). Nitric oxide release was measured colorimetrically by NO assay kit. The expression of nNOSα and dimerization was detected by Western blot. KEY RESULTS In vitro studies on gastric muscular tissues showed that MTX, an inhibitor of BH₄ synthesis via salvage pathway, significantly decreased NO release. In vivo treatment with MTX reduced both gastric nitrergic relaxation and nNOSα dimerization. Supplementation of SEP significantly attenuated delayed gastric emptying in diabetic rats. In addition, SEP supplementation restored impaired nitrergic relaxation, gastric nNOSα protein expression, and dimerization in diabetic rats. CONCLUSIONS & INFERENCES The above data suggests that supplementation of SEP accelerated gastric emptying and attenuated reduced gastric nNOSα expression, and dimerization. Therefore, SEP supplementation is a potential therapeutic option for female patients of diabetic gastroparesis.
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Affiliation(s)
- P. R. R. GANGULA
- Department of physiology, Center for Women’s Health Research, Meharry Medical College, Nashville, TN, USA
| | - S. MUKHOPADHYAY
- Department of physiology, Center for Women’s Health Research, Meharry Medical College, Nashville, TN, USA
| | - P. J. PASRICHA
- Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA, USA
| | - K. RAVELLA
- Department of physiology, Center for Women’s Health Research, Meharry Medical College, Nashville, TN, USA
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Jiang X, Kim B, Lin H, Lee CK, Kim J, Kang H, Lee P, Jung SH, Lee HM, Won KJ. Tetrahydrobiopterin Inhibits PDGF-stimulated Migration and Proliferation in Rat Aortic Smooth Muscle Cells via the Nitric Oxide Synthase-independent Pathway. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2010; 14:177-83. [PMID: 20631891 DOI: 10.4196/kjpp.2010.14.3.177] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 06/14/2010] [Accepted: 06/17/2010] [Indexed: 11/15/2022]
Abstract
Tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthase (NOS) activity, is known to play important roles in modulating both NO and superoxide production during vascular diseases such as atherosclerosis. However, the role of BH4 in functions of vascular smooth muscle cells is not fully known. In this study, we tested the effects of BH4 and dihydrobiopterin (BH2), a BH4 precursor, on migration and proliferation in response to platelet-derived growth factor-BB (PDGF-BB) in rat aortic smooth muscle cells (RASMCs). Cell migration and proliferation were measured using a Boyden chamber and a 5-bromo-2'-deoxyuridine incorporation assay, respectively, and these results were confirmed with an ex vivo aortic sprout assay. Cell viability was examined by 2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide assays. BH4 and BH2 decreased PDGF-BB-induced cell migration and proliferation in a dose-dependent manner. The inhibition of cell migration and proliferation by BH4 and BH2 was not affected by pretreatment with N(G)-nitro-L-arginine methyl ester, a NOS inhibitor. Moreover, the sprout outgrowth formation of aortic rings induced by PDGF-BB was inhibited by BH4 and BH2. Cell viability was not inhibited by BH4 and BH2 treatment. The present results suggest that BH4 and BH2 may inhibit PDGF-stimulated RASMC migration and proliferation via the NOS-independent pathway. Therefore, BH4 and its derivative could be useful for the development of a candidate molecule with an NO-independent anti-atherosclerotic function.
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Affiliation(s)
- Xiaowen Jiang
- Departments of Physiology and Biotechnology, Konkuk University, Chungju 380-701, Korea
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Hasegawa H, Nakamura K. Tryptophan Hydroxylase and Serotonin Synthesis Regulation. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70078-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Vásquez-Vivar J, Whitsett J, Derrick M, Ji X, Yu L, Tan S. Tetrahydrobiopterin in the prevention of hypertonia in hypoxic fetal brain. Ann Neurol 2009; 66:323-31. [PMID: 19798726 PMCID: PMC2785106 DOI: 10.1002/ana.21738] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Tetrahydrobiopterin (BH(4)) deficiency is a cause of dystonia at birth. We hypothesized that BH(4) is a developmental factor determining vulnerability of the immature fetal brain to hypoxic-ischemic injury and subsequent motor deficits in newborns. METHODS Pregnant rabbits were subjected to 40-minute uterine ischemia, and fetal brains were investigated for global and focal changes in BH(4). Newborn kits were assessed by neurobehavioral tests following vehicle and sepiapterin (BH(4) analog) treatment of dams. RESULTS Naive fetal brains at 70% gestation (E22) were severely deficient for BH(4) compared with maternal and other fetal tissues. BH(4) concentration rapidly increased normally in the perinatal period, with the highest concentrations found in the thalamus compared with basal ganglia, frontal, occipital, hippocampus, and parietal cortex. Global sustained 40-minute hypoxia-ischemia depleted BH(4) in E22 thalamus and to a lesser extent in basal ganglia, but not in the frontal, occipital, and parietal regions. Maternal supplementation prior to hypoxia-ischemia with sepiapterin increased BH(4) in all brain regions and especially in the thalamus, but did not increase the intermediary metabolite, 7,8-BH(2). Sepiapterin treatment also reduced incidence of severe motor deficits and perinatal death following E22 hypoxia-ischemia. INTERPRETATION We conclude that early developmental BH(4) deficiency plays a critical role in hypoxic-ischemic brain injury. Increasing brain BH(4) via maternal supplementation may be an effective strategy in preventing motor deficits from antenatal hypoxia-ischemia.
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Sugiyama T, Levy BD, Michel T. Tetrahydrobiopterin recycling, a key determinant of endothelial nitric-oxide synthase-dependent signaling pathways in cultured vascular endothelial cells. J Biol Chem 2009; 284:12691-700. [PMID: 19286667 PMCID: PMC2675998 DOI: 10.1074/jbc.m809295200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 03/09/2009] [Indexed: 02/06/2023] Open
Abstract
Tetrahydrobiopterin (BH4) is a key redox-active cofactor in endothelial isoform of NO synthase (eNOS) catalysis and is an important determinant of NO-dependent signaling pathways. BH4 oxidation is observed in vascular cells in the setting of the oxidative stress associated with diabetes. However, the relative roles of de novo BH4 synthesis and BH4 redox recycling in the regulation of eNOS bioactivity remain incompletely defined. We used small interference RNA (siRNA)-mediated "knockdown" GTP cyclohydrolase-1 (GTPCH1), the rate-limiting enzyme in BH4 biosynthesis, and dihydrofolate reductase (DHFR), an enzyme-recycling oxidized BH4 (7,8-dihydrobiopterin (BH2)), and studied the effects on eNOS regulation and biopterin metabolism in cultured aortic endothelial cells. Knockdown of either DHFR or GTPCH1 attenuated vascular endothelial growth factor (VEGF)-induced eNOS activity and NO production; these effects were recovered by supplementation with BH4. In contrast, supplementation with BH2 abolished VEGF-induced NO production. DHFR but not GTPCH1 knockdown increased reactive oxygen species (ROS) production. The increase in ROS production seen with siRNA-mediated DHFR knockdown was abolished either by simultaneous siRNA-mediated knockdown of eNOS or by supplementing with BH4. In contrast, addition of BH2 increased ROS production; this effect of BH2 was blocked by BH4 supplementation. DHFR but not GTPCH1 knockdown inhibited VEGF-induced dephosphorylation of eNOS at the inhibitory site serine 116; these effects were recovered by supplementation with BH4. These studies demonstrate a striking contrast in the pattern of eNOS regulation seen by the selective modulation of BH4 salvage/reduction versus de novo BH4 synthetic pathways. Our findings suggest that the depletion of BH4 is not sufficient to perturb NO signaling, but rather that concentration of intracellular BH2, as well as the relative concentrations of BH4 and BH2, together play a determining role in the redox regulation of eNOS-modulated endothelial responses.
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Affiliation(s)
- Toru Sugiyama
- Cardiovascular and Pulmonary Divisions, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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Nakamura K, Hasegawa H. Production and Peripheral Roles of 5-HTP, a Precursor of Serotonin. Int J Tryptophan Res 2009; 2:37-43. [PMID: 22084581 PMCID: PMC3195225 DOI: 10.4137/ijtr.s1022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Serotonin (5-hydroxytryptamine [5-HT]) has been implicated in a variety of physiological and pathological functions. Multiple steps of enzyme reactions enable biosynthesis of 5-HT. The first and rate-limiting step of the reaction is the synthesis of 5-hydroxy-L-tryptophan (5-HTP) from L-tryptophan. This step is dictated by an enzyme, tryptophan hydroxylase (TPH). TPH requires 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4) as a co-substrate of TPH. 5-HTP has been simply regarded as a precursor of 5-HT and it is believed that the biological significance of 5-HTP is essentially ascribed to the production of 5-HT. However, recent works shed light on the specific functions of 5-HTP in the periphery. In this review article, we focus on the specific roles of exogenous 5-HTP as well as the endogenous 5-HTP in the gut epithelial cells. Since systemic treatment with 5-HTP is applied to patients with lower 5-HT levels, the studies on the specific role of 5-HTP might create an opportunity to explore the effects of exogenously-applied 5-HTP in the gut in man.
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Affiliation(s)
- Kazuhiro Nakamura
- Department of Pathology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
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Ohashi A, Fukumuro M, Sawabe K, Mamada K, Sugawara Y, Matsuoka H, Hasegawa H. Transcellular relocation of tetrahydrobiopterin across Caco-2 cells: a model study of tetrahydrobiopterin absorption through epithelial cells of intestinal mucosa. J Inherit Metab Dis 2009; 32:73-8. [PMID: 18979179 DOI: 10.1007/s10545-008-0961-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 08/18/2008] [Accepted: 08/30/2008] [Indexed: 11/28/2022]
Abstract
Oral administration of tetrahydrobiopterin (BH(4)) has been known to be effective in treating BH(4)-deficient patients. It has long been established that BH(4) is absorbed by the intestinal mucosa. However, the mechanism for translocation of BH(4) across epithelial cells has not been elucidated. In order to study BH(4) transport mechanisms, Caco-2 cells were employed in this study as an epithelial cell model. Caco-2 cells were cultured (2 x 10(4) cells/0.3 cm(2) well) for 21 days in a 24-well format using Transwell, a porous membrane-based culture dish, at which point they had established themselves as a tight sheet with a definite polarity. When BH(4) (100 micromol/L) was given to cells from the apical side, a considerable translocation toward their basolateral side was noted. The rate of BH(4) movement was around 150 pmol/h per well. This was comparable to the highest rate of BH(4) uptake or its release so far obtained using a monolayer culture of Caco-2 cells on an ordinary plastic plate. The transcellular movement of BH(4) across the polar culture on the porous membrane was effectively prevented by benzbromarone (10 micromol/L), a well known inhibitor of a group of transporters including urate transporter (URAT1), organic anion transporters (OATs), and multidrug-resistance-associated proteins (MRPs). It was thus concluded that in Caco-2 cells, BH(4) moved across the cell interior in a rapid ligand-specific manner that was driven by a transporter.
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Affiliation(s)
- A Ohashi
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi, Japan
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Sawabe K, Saeki Y, Ohashi A, Mamada K, Wakasugi KO, Matsuoka H, Hasegawa H. Tetrahydrobiopterin in intestinal lumen: its absorption and secretion in the small intestine and the elimination in the large intestine. J Inherit Metab Dis 2009; 32:79-85. [PMID: 19031009 DOI: 10.1007/s10545-008-0964-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 09/22/2008] [Accepted: 10/15/2008] [Indexed: 11/29/2022]
Abstract
In treating hereditary deficiency of tetrahydrobiopterin (BH(4)), supplementation with BH(4) might be the ultimate choice of therapy. Oral administration of BH(4) has been believed to be inefficient owing to poor absorption of BH(4) in the intestine. In this study, we found a considerable amount of BH(4) as well as its oxidized pterins in the ingredients of intestinal lumen of mice when they were served food that did not contain significant amounts of biopterin. Ligation of the biliary duct led to significant decrease in luminal biopterin. Supplementation of BH(4) either by intraperitoneal administration of sepiapterin or of 6RBH(4) ((6R)-L-erythro-5,6,7,8-tetrahydrobiopterin) increased the BH(4) content in the intestinal lumen with a slight delay after the rise of blood BH(4). In these mice, biopterin appeared in the large intestine, caecum and colon, 2 h after the administration. The appearance of BH(4) in the large intestine was accompanied by a large amount of pterin (2-amino-4-hydroxypteridine). The amounts of biopterin + pterin that appeared in the large intestine after intraperitoneal administration of BH(4) were not greater than those found after oral administration at the same dose. When the mice were treated with a large dose of antibiotics prior to the BH(4) administration, the amount of biopterin increased in the caecum but the amount of pterin decreased greatly. These results suggested that a large proportion of BH(4) administered moved to the large intestine, where most biopterin was decomposed presumably by enteric bacteria. Nonetheless, most of the orally administered biopterin was taken up by the small intestine and the amount of biopterin reaching the large intestine was almost the same as that which appeared after direct injection of 6RBH(4) into the peritoneal cavity.
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Affiliation(s)
- K Sawabe
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi, Japan
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Katusic ZS, d'Uscio LV, Nath KA. Vascular protection by tetrahydrobiopterin: progress and therapeutic prospects. Trends Pharmacol Sci 2009; 30:48-54. [PMID: 19042039 PMCID: PMC2637534 DOI: 10.1016/j.tips.2008.10.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/23/2008] [Accepted: 10/24/2008] [Indexed: 02/07/2023]
Abstract
Tetrahydrobiopterin (BH4) is an essential cofactor required for the activity of endothelial nitric oxide (NO) synthase. Suboptimal concentrations of BH4 in the endothelium reduce the biosynthesis of NO, thus contributing to the pathogenesis of vascular endothelial dysfunction. Supplementation with exogenous BH4 or therapeutic approaches that increase endogenous amounts of BH4 can reduce or reverse endothelial dysfunction by restoring production of NO. Improvements in formulations of BH4 for oral delivery have stimulated clinical trials that test the efficacy of BH4 in the treatment of systemic hypertension, peripheral arterial disease, coronary artery disease, pulmonary arterial hypertension, and sickle cell disease. This review discusses ongoing progress in the translation of knowledge, accumulated in preclinical studies, into the clinical application of BH4 in the treatment of vascular diseases. This review also addresses the emerging roles of BH4 in the regulation of endothelial function and their therapeutic implications.
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Affiliation(s)
- Zvonimir S Katusic
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Ionova IA, Vásquez-Vivar J, Whitsett J, Herrnreiter A, Medhora M, Cooley BC, Pieper GM. Deficient BH4 production via de novo and salvage pathways regulates NO responses to cytokines in adult cardiac myocytes. Am J Physiol Heart Circ Physiol 2008; 295:H2178-87. [PMID: 18835915 PMCID: PMC2614582 DOI: 10.1152/ajpheart.00748.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 09/25/2008] [Indexed: 12/25/2022]
Abstract
Adult rat cardiac myocytes typically display a phenotypic response to cytokines manifested by low or no increases in nitric oxide (NO) production via inducible NO synthase (iNOS) that distinguishes them from other cell types. To better characterize this response, we examined the expression of tetrahydrobiopterin (BH4)-synthesizing and arginine-utilizing genes in cytokine-stimulated adult cardiac myocytes. Intracellular BH4 and 7,8-dihydrobiopterin (BH2) and NO production were quantified. Cytokines induced GTP cyclohydrolase and its feedback regulatory protein but with deficient levels of BH4 synthesis. Despite the induction of iNOS protein, cytokine-stimulated adult cardiac myocytes produced little or no increase in NO versus unstimulated cells. Western blot analysis under nonreducing conditions revealed the presence of iNOS monomers. Supplementation with sepiapterin (a precursor of BH4) increased BH4 as well as BH2, but this did not enhance NO levels or eliminate iNOS monomers. Similar findings were confirmed in vivo after treatment of rat cardiac allograft recipients with sepiapterin. It was found that expression of dihydrofolate reductase, required for full activity of the salvage pathway, was not detected in adult cardiac myocytes. Thus, adult cardiac myocytes have a limited capacity to synthesize BH4 after cytokine stimulation. The mechanisms involve posttranslational factors impairing de novo and salvage pathways. These conditions are unable to support active iNOS protein dimers necessary for NO production. These findings raise significant new questions about the prevailing understanding of how cytokines, via iNOS, cause cardiac dysfunction and injury in vivo during cardiac inflammatory disease states since cardiac myocytes are not a major source of high NO production.
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Affiliation(s)
- Irina A Ionova
- Department of Surgery (Transplant Surgery), Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA
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Sawabe K, Yamamoto K, Harada Y, Ohashi A, Sugawara Y, Matsuoka H, Hasegawa H. Cellular uptake of sepiapterin and push-pull accumulation of tetrahydrobiopterin. Mol Genet Metab 2008; 94:410-416. [PMID: 18511317 DOI: 10.1016/j.ymgme.2008.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2008] [Revised: 04/12/2008] [Accepted: 04/12/2008] [Indexed: 11/28/2022]
Abstract
Cellular uptake of sepiapterin resulted in an efficient accumulation of tetrahydrobiopterin. Tetrahydrobiopterin is much less permeable across the cell membrane than sepiapterin or dihydrobiopterin, the precursors of the tetrahydrobiopterin-salvage pathway. The uptake of sepiapterin by the cell was examined under metabolic arrest with N-acetylserotonin, an inhibitor of sepiapterin reductase. The release profile of previously accumulated sepiapterin was also analyzed. Two routes were clearly distinguishable, namely rapid and slow. Both were apparently bi-directional and equilibrating in type. Each route was connected to non-mixable pools somehow separated in the cell. The rapid process was too fast to analyze by the current methods of cell handling. The slower process was associated with conversion of sepiapterin to tetrahydrobiopterin in the absence of N-acetylserotonin, suggesting that this route opens into the cytosolic compartment where use of the salvage pathway was strongly driven by sepiapterin reductase and dihydrofolate reductase with a supply of NADPH which favors tetrahydrobiopterin accumulation. Consequently, sepiapterin was enforcedly taken up by the cell where it accumulated tetrahydrobiopterin in the cytosol in continuous manner.
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Affiliation(s)
- Keiko Sawabe
- Biotechnology Research Center, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
| | - Kazumasa Yamamoto
- Biotechnology Research Center, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
| | - Yoshinori Harada
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
| | - Akiko Ohashi
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
| | - Yuko Sugawara
- Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
| | - Hiroshi Matsuoka
- Biotechnology Research Center, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan; Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
| | - Hiroyuki Hasegawa
- Biotechnology Research Center, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan; Department of Biosciences, Teikyo University of Science and Technology, Uenohara, Yamanashi 409-0193, Japan
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50
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Wenzel P, Daiber A, Oelze M, Brandt M, Closs E, Xu J, Thum T, Bauersachs J, Ertl G, Zou MH, Förstermann U, Müunzel T. Mechanisms underlying recoupling of eNOS by HMG-CoA reductase inhibition in a rat model of streptozotocin-induced diabetes mellitus. Atherosclerosis 2008; 198:65-76. [PMID: 18061195 PMCID: PMC2889614 DOI: 10.1016/j.atherosclerosis.2007.10.003] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2007] [Revised: 09/29/2007] [Accepted: 10/01/2007] [Indexed: 02/07/2023]
Abstract
OBJECTIVE HMG-CoA reductase inhibitors have been shown to upregulate GTP cyclohydrolase I (GTPCH-I), the key enzyme for tetrahydrobiopterin de novo synthesis and to normalize tetrahydrobiopterin levels in hyperglycemic endothelial cells. We sought to determine whether in vivo treatment with the HMG-CoA reductase inhibitor atorvastatin is able to upregulate the GTPCH-I, to recouple eNOS and to normalize endothelial dysfunction in an experimental model of diabetes mellitus. METHODS AND RESULTS In male Wistar rats, diabetes was induced by streptozotocin (STZ, 60 mg/kg). In STZ rats, atorvastatin feeding (20 mg/kg/d, 7 weeks), normalized vascular dysfunction as analyzed by isometric tension studies, levels of circulating endothelial progenitor cells (FACS-analysis), superoxide formation (assessed by lucigenin-enhanced chemiluminescence and dihydroethidium staining), vascular levels of the phosphorylated vasodilator-stimulated phosphoprotein (P-VASP), tyrosine nitration of the prostacyclin synthase, expression of GTPCH-I, dihydrofolate reductase and eNOS, translocation of regulatory NADPH oxidase subunits rac1, p47phox and p67phox (assessed by Western blot) and vascular tetrahydrobiopterin levels as measured by HPLC. Dihydroethidine staining revealed that the reduction of vascular superoxide was at least in part due to eNOS recoupling. CONCLUSION HMG-CoA reductase inhibition normalizes endothelial function and reduces oxidative stress in diabetes by inhibiting activation of the vascular NADPH oxidase and by preventing eNOS uncoupling due to an upregulation of the key enzyme of tetrahydrobiopterin synthesis, GTPCH-I.
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Affiliation(s)
- Philip Wenzel
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Andreas Daiber
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Matthias Oelze
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Moritz Brandt
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
| | - Ellen Closs
- Department of Pharmacology, Johannes-Gutenberg-University, Obere Zahlbacher Strasse 67, 55131 Mainz, Germany
| | - Jian Xu
- Department of Medicine and Endocrinology, University of Oklahoma Health Science Center, 941 Stanton L. Young Blvd., Oklahoma City, OK 73013, USA
| | - Thomas Thum
- Medical Clinic I, Department of Cardiology, Bavarian Julius-Maximilians-University Wurzburg Klinikstrasse 6-8, 97070 Würzburg, Germany
| | - Johann Bauersachs
- Medical Clinic I, Department of Cardiology, Bavarian Julius-Maximilians-University Wurzburg Klinikstrasse 6-8, 97070 Würzburg, Germany
| | - Georg Ertl
- Medical Clinic I, Department of Cardiology, Bavarian Julius-Maximilians-University Wurzburg Klinikstrasse 6-8, 97070 Würzburg, Germany
| | - Ming-Hui Zou
- Department of Medicine and Endocrinology, University of Oklahoma Health Science Center, 941 Stanton L. Young Blvd., Oklahoma City, OK 73013, USA
| | - Ulrich Förstermann
- Department of Pharmacology, Johannes-Gutenberg-University, Obere Zahlbacher Strasse 67, 55131 Mainz, Germany
| | - Thomas Müunzel
- Second Medical Clinic, Department of Cardiology and Angiology, Johannes-Gutenberg-University, Langenbeckstrasse 1, 55131 Mainz, Germany
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