1
|
Lains I, Han X, Gil J, Providencia J, Nigalye A, Alvarez R, Douglas VP, Mendez K, Katz R, Tsougranis G, Li J, Kelly RS, Kim IK, Lasky-Su J, Silva R, Miller JW, Liang L, Vavvas D, Miller JB, Husain D. Plasma Metabolites Associated with OCT Features of Age-Related Macular Degeneration. OPHTHALMOLOGY SCIENCE 2024; 4:100357. [PMID: 37869026 PMCID: PMC10587636 DOI: 10.1016/j.xops.2023.100357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 05/13/2023] [Accepted: 06/06/2023] [Indexed: 10/24/2023]
Abstract
Purpose The most widely used classifications of age-related macular degeneration (AMD) and its severity stages still rely on color fundus photographs (CFPs). However, AMD has a wide phenotypic variability that remains poorly understood and is better characterized by OCT. We and others have shown that patients with AMD have a distinct plasma metabolomic profile compared with controls. However, all studies to date have been performed solely based on CFP classifications. This study aimed to assess if plasma metabolomic profiles are associated with OCT features commonly seen in AMD. Design Prospectively designed, cross-sectional study. Participants Subjects with a diagnosis of AMD and a control group (> 50 years old) from Boston, United States, and Coimbra, Portugal. Methods All participants were imaged with CFP, used for AMD staging (Age-Related Eye Disease Study 2 classification scheme), and with spectral domain OCT (Spectralis, Heidelberg). OCT images were graded by 2 independent graders for the presence of characteristic AMD features, according to a predefined protocol. Fasting blood samples were collected for metabolomic profiling (using nontargeted high-resolution mass spectrometry by Metabolon Inc). Analyses were conducted using logistic regression models including the worst eye of each patient (AREDS2 classification) and adjusting for confounding factors. Each cohort (United States and Portugal) was analyzed separately and then results were combined by meta-analyses. False discovery rate (FDR) was used to account for multiple comparisons. Main Outcome Measures Plasma metabolite levels associated with OCT features. Results We included data on 468 patients, 374 with AMD and 94 controls, and on 725 named endogenous metabolites. Meta-analysis identified significant associations (FDR < 0.05) between plasma metabolites and 3 OCT features: hyperreflective foci (6), atrophy (6), and ellipsoid zone disruption (3). Most associations were seen with amino acids, and all but 1 metabolite presented specific associations with the OCT features assessed. Conclusions To our knowledge, we show for the first time that plasma metabolites have associations with specific OCT features seen in AMD. Our results support that the wide spectrum of presentations of AMD likely include different pathophysiologic mechanisms by identifying specific pathways associated with each OCT feature. Financial Disclosures Proprietary or commercial disclosure may be found after the references.
Collapse
Affiliation(s)
- Ines Lains
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Xikun Han
- Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, Massachusetts
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T H Chan School of Public Health, Boston, Massachusetts
| | - João Gil
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | - Joana Providencia
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
| | - Archana Nigalye
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Rodrigo Alvarez
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Vivian Paraskevi Douglas
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Kevin Mendez
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Raviv Katz
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Gregory Tsougranis
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Jinglun Li
- Department of Biostatistics, Harvard T H Chan School of Public Health, Boston, Massachusetts
| | - Rachel S. Kelly
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Ivana K. Kim
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Jessica Lasky-Su
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Rufino Silva
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Ophthalmology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, Coimbra, Portugal
- Clinical Academic Center of Coimbra (CCAC), Coimbra, Portugal
| | - Joan W. Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Liming Liang
- Department of Biostatistics, Harvard T H Chan School of Public Health, Boston, Massachusetts
| | - Demetrios Vavvas
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - John B. Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| | - Deeba Husain
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
2
|
Ramsay E, Lajunen T, Bhattacharya M, Reinisalo M, Rilla K, Kidron H, Terasaki T, Urtti A. Selective drug delivery to the retinal cells: Biological barriers and avenues. J Control Release 2023; 361:1-19. [PMID: 37481214 DOI: 10.1016/j.jconrel.2023.07.028] [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: 10/14/2022] [Revised: 06/09/2023] [Accepted: 07/16/2023] [Indexed: 07/24/2023]
Abstract
Retinal drug delivery is a challenging, but important task, because most retinal diseases are still without any proper therapy. Drug delivery to the retina is hampered by the anatomical and physiological barriers resulting in minimal bioavailability after topical ocular and systemic administrations. Intravitreal injections are current method-of-choice in retinal delivery, but these injections show short duration of action for small molecules and low target bioavailability for many protein, gene based drugs and nanomedicines. State-of-art delivery systems are based on prolonged retention, controlled drug release and physical features (e.g. size and charge). However, drug delivery to the retina is not cell-specific and these approaches do not facilitate intracellular delivery of modern biological drugs (e.g. intracellular proteins, RNA based medicines, gene editing). In this focused review we highlight biological factors and mechanisms that form the basis for the selective retinal drug delivery systems in the future. Therefore, we are presenting current knowledge related to retinal membrane transporters, receptors and targeting ligands in relation to nanomedicines, conjugates, extracellular vesicles, and melanin binding. These issues are discussed in the light of retinal structure and cell types as well as future prospects in the field. Unlike in some other fields of targeted drug delivery (e.g. cancer research), selective delivery technologies have been rarely studied, even though cell targeted delivery may be even more feasible after local administration into the eye.
Collapse
Affiliation(s)
- Eva Ramsay
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland
| | - Tatu Lajunen
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland; School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Madhushree Bhattacharya
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland
| | - Mika Reinisalo
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Kirsi Rilla
- School of Medicine, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Heidi Kidron
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland
| | - Tetsuya Terasaki
- School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland
| | - Arto Urtti
- Drug Research Programme, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 University of Helsinki, Finland; School of Pharmacy, University of Eastern Finland, Yliopistonranta 1 C, 70211 Kuopio, Finland.
| |
Collapse
|
3
|
Jomura R, Akanuma SI, Tachikawa M, Hosoya KI. SLC6A and SLC16A family of transporters: Contribution to transport of creatine and creatine precursors in creatine biosynthesis and distribution. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183840. [PMID: 34921896 DOI: 10.1016/j.bbamem.2021.183840] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 11/16/2022]
Abstract
Creatine (Cr) is needed to maintain high energy levels in cells. Since Cr plays reportedly a critical role in neurodevelopment and the immune system, Cr dynamics should be strictly regulated to control these physiological events. This review focuses on the role of transporters that recognize Cr and/or Cr precursors. Our previous studies revealed physiological roles of SLC6A and SLC16A family transporters in Cr dynamics. Creatine transporter (CRT/SLC6A8) contributes to the influx transport of Cr in Cr distribution. γ-Aminobutyric acid transporter 2 (GAT2/SLC6A13) mediates incorporation of guanidinoacetate (GAA), a Cr precursor, in the process of Cr biosynthesis. Monocarboxylate transporter 12 (MCT12/SLC16A12) functions as an efflux transporter for Cr and GAA, and contributes to the process of Cr biosynthesis. Accordingly, the SLC6A and SLC16A family of transporters play important roles in the process of Cr biosynthesis and distribution via permeation of Cr and Cr precursors across the plasma membrane.
Collapse
Affiliation(s)
- Ryuta Jomura
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
| | - Shin-Ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
| | - Masanori Tachikawa
- Graduate School of Biomedical Sciences, Tokushima University, 1-78-1 Shomachi, Tokushima 770-8505, Japan.
| | - Ken-Ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
| |
Collapse
|
4
|
Involvement of TauT/SLC6A6 in Taurine Transport at the Blood-Testis Barrier. Metabolites 2022; 12:metabo12010066. [PMID: 35050188 PMCID: PMC8782047 DOI: 10.3390/metabo12010066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/07/2022] [Accepted: 01/08/2022] [Indexed: 12/30/2022] Open
Abstract
Taurine transport was investigated at the blood–testis barrier (BTB) formed by Sertoli cells. An integration plot analysis of mice showed the apparent influx permeability clearance of [3H]taurine (27.7 μL/(min·g testis)), which was much higher than that of a non-permeable paracellular marker, suggesting blood-to-testis transport of taurine, which may involve a facilitative taurine transport system at the BTB. A mouse Sertoli cell line, TM4 cells, showed temperature- and concentration-dependent [3H]taurine uptake with a Km of 13.5 μM, suggesting that the influx transport of taurine at the BTB involves a carrier-mediated process. [3H]Taurine uptake by TM4 cells was significantly reduced by the substrates of taurine transporter (TauT/SLC6A6), such as β-alanine, hypotaurine, γ-aminobutyric acid (GABA), and guanidinoacetic acid (GAA), with no significant effect shown by L-alanine, probenecid, and L-leucine. In addition, the concentration-dependent inhibition of [3H]taurine uptake revealed an IC50 of 378 μM for GABA. Protein expression of TauT in the testis, seminiferous tubules, and TM4 cells was confirmed by Western blot analysis and immunohistochemistry by means of anti-TauT antibodies, and knockdown of TauT showed significantly decreased [3H]taurine uptake by TM4 cells. These results suggest the involvement of TauT in the transport of taurine at the BTB.
Collapse
|
5
|
Ren F, Liu X, Liu X, Cao Y, Liu L, Li X, Wu Y, Du S, Tian G, Hu J. In vitro and in vivo study on prevention of myocardial ischemic injury by taurine. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:984. [PMID: 34277784 PMCID: PMC8267305 DOI: 10.21037/atm-21-2481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/15/2021] [Indexed: 11/10/2022]
Abstract
Background Myocardial ischemia (MI) often causes angina, arrhythmia, and cardiac insufficiency, sometimes resulting in death. Ischemia-induced myocardial tissue damage is attributed to the hypoxic damage of myocardial cells producing apoptosis and decreased proliferation. Taurine has been shown to improve MI, but its mechanism is largely unknown. Methods In this study, the relationship between taurine and severity of MI in vivo was evaluated by quantifying myocardial infarct areas and metabolic indicators of myocardial damage and measuring taurine levels in cardiac muscle and plasma by high performance liquid chromatography (HPLC). To elucidate how taurine might suppress ischemic injury, we established an in vitro ischemia model with isolated primary rat cardiomyocytes cultured without serum or glucose and under hypoxia. We evaluated the indicators of MI and damage, including lactic dehydrogenase (LDH), creatine kinase (CK), and cardiac troponin I (cTnI). We also examined the levels of taurine transporter (TauT), cysteine dioxygenase (CDO), and cysteine sulfinate decarboxylase (CSD) proteins involved in transport and synthesis of taurine in the myocardium and those of 2 apoptosis-associated proteins, namely, Bcl-2 associated X protein (BAX) and B-cell lymphoma-2 (Bcl-2). Results Exposure of myocardial cells to ischemia led to the decrease of taurine content, the suppression of cell proliferation, and led to calcium ion overload and apoptosis. Pretreatment with taurine alleviated the ischemic damage, with concomitant elevation of intracellular taurine concentrations. Molecular mechanism analysis showed that pretreatment with taurine upregulated the TauT, CDO, and CSD, 2 rate-limiting enzymes involved in taurine synthesis. These effects facilitated both taurine transport into cells and taurine synthesis, leading to taurine accumulation. In addition, apoptosis inhibition by taurine appeared to be mediated by upregulated Bcl-2 and downregulated BAX, as well as inhibition of calcium overload by suppression of calcium binding protein. Conclusions We demonstrated that TauT is critical for the attenuation of myocardial ischemic damage by taurine, facilitating taurine absorption and synthesis. These findings provided new insights and a theoretical foundation for future studies examining taurine as a potential treatment for MI.
Collapse
Affiliation(s)
- Fengyun Ren
- Department of Anatomy, School of Basic Medicine, Jiamusi University, Jiamusi, China.,School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Xing Liu
- Department of Anatomy, School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Xiaoxue Liu
- School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Yanli Cao
- School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Lantao Liu
- School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Xingjiang Li
- Department of Anatomy, School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Yingjun Wu
- School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Shudi Du
- School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| | - Guozhong Tian
- Department of Anatomy, School of Basic Medicine, Jiamusi University, Jiamusi, China
| | - Jing Hu
- School of Basic Medicine, Mudanjiang Medical University, Mudanjiang, China
| |
Collapse
|
6
|
Forouzanfar F, Shojapour M, Aghili ZS, Asgharzade S. Growth Factors as Tools in Photoreceptor Cell Regeneration and Vision Recovery. Curr Drug Targets 2021; 21:573-581. [PMID: 31755378 DOI: 10.2174/1389450120666191121103831] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/04/2019] [Accepted: 10/18/2019] [Indexed: 02/08/2023]
Abstract
Photoreceptor loss is a major cause of blindness around the world. Stem cell therapy offers a new strategy in retina degenerative disease. Retinal progenitors can be derived from embryonic stem cells (ESC) in vitro, but cannot be processed to a mature state. In addition, the adult recipient retina presents a very different environment than the photoreceptor precursor donor. It seems that modulation of the recipient environment by ectopic development regulated growth factors for transplanted cells could generate efficient putative photoreceptors. The purpose of this review article was to investigate the signaling pathway of growth factors including: insulin-like growth factors (IGFs), fibroblast growth factors (FGF), Nerve growth factor (NGF), Brain-derived neurotrophic factor (BDNF), Taurin and Retinoic acid (RA) involved in the differentiation of neuroretina cell, like; photoreceptor and retinal progenitor cells. Given the results available in the related literature, the differentiation efficacy of ESCs toward the photoreceptor and retinal neurons and the important role of growth factors in activating signaling pathways such as Akt, Ras/Raf1/ and ERKs also inhibit the ASK1/JNK apoptosis pathway. Manipulating differentiated culture, growth factors can influence photoreceptor transplantation efficiency in retinal degenerative disease.
Collapse
Affiliation(s)
- Fatemeh Forouzanfar
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Department of Neuroscience, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mana Shojapour
- Molecular and Medicine Research Center, Arak University of Medical Sciences, Arak, Iran
| | - Zahra Sadat Aghili
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Samira Asgharzade
- Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
| |
Collapse
|
7
|
Neelam K, Dey S, Sim R, Lee J, Au Eong KG. Fructus lycii: A Natural Dietary Supplement for Amelioration of Retinal Diseases. Nutrients 2021; 13:246. [PMID: 33467087 PMCID: PMC7830576 DOI: 10.3390/nu13010246] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/02/2021] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
Fructus lycii (F. lycii) is an exotic "berry-type" fruit of the plant Lycium barbarum that is characterized by a complex mixture of bioactive compounds distinguished by their high antioxidant potential. F. lycii is used in traditional Chinese home cooking and in the Chinese Pharmacopeia as an aid to vision and longevity as well as a remedy for diabetes to balance "yin" and "yang" in the body for about two centuries. Although a myriad of bioactive compounds have been isolated from F. lycii, polysaccharides, carotenoids, flavonoids, and phenolics represent the key functional components of F. lycii. F. lycii has been shown to exhibit a wide range of biological activities in experimental settings including antioxidant, anti-inflammatory, antiapoptotic, and neuroprotective effects. Despite its medicinal role dating back to the eighteenth century in the Far East and robust evidence of beneficial effects on ocular health and retinal diseases originating mainly from studies in animal models, the role of F. lycii in the clinical management of retinal diseases is yet to be established. This article comprehensively reviews the literature germane to F. lycii and retinal diseases with particular emphasis on age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa, which are commonly seen in clinical practice.
Collapse
Affiliation(s)
- Kumari Neelam
- Department of Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, Singapore 768828, Singapore; (J.L.); (K.-G.A.E.)
- Singapore Eye Research Institute, Singapore 169856, Singapore
| | - Sonali Dey
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; (S.D.); (R.S.)
| | - Ralene Sim
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore; (S.D.); (R.S.)
| | - Jason Lee
- Department of Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, Singapore 768828, Singapore; (J.L.); (K.-G.A.E.)
| | - Kah-Guan Au Eong
- Department of Ophthalmology and Visual Sciences, Khoo Teck Puat Hospital, Singapore 768828, Singapore; (J.L.); (K.-G.A.E.)
- International Eye Cataract Retina Center, Farrer Park Medical Center, Singapore 217562, Singapore
| |
Collapse
|
8
|
Gyawali A, Kim MH, Kang YS. A novel organic cation transporter involved in paeonol transport across the inner blood-retinal barrier and changes in uptake in high glucose conditions. Exp Eye Res 2020; 202:108387. [PMID: 33301773 DOI: 10.1016/j.exer.2020.108387] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/06/2020] [Accepted: 12/01/2020] [Indexed: 12/29/2022]
Abstract
Paeonol exerts various pharmacological effects owing to its antiangiogenic, antioxidant, and antidiabetic activities. We aimed to investigate the transport mechanism of paeonol across the inner blood-retinal barrier both in vitro and in vivo. The carotid artery single injection method was used to investigate the retina uptake index of paeonol. The retina uptake index (RUI) value of [³H]paeonol was dependent on both concentration and pH. This value decreased significantly in the presence of imperatorin, tramadol, and pyrilamine when compared to the control. However, para-aminohippuric acid, choline, and taurine had no effect on the RUI value. Conditionally immortalized rat retina capillary endothelial cells (TR-iBRB cell lines) were used as an in vitro model of the inner blood-retinal barrier (iBRB). The uptake of [³H]paeonol by the TR-iBRB cell lines was found to be time-, concentration-, and pH-dependent. However, the uptake was unaffected by the absence of sodium or by membrane potential disruption. Moreover, in vitro structural analog studies revealed that [³H]paeonol uptake was inhibited in the presence of organic cationic compounds including imperatorin, clonidine and tramadol. This is consistent with the results obtained in vivo. In addition, transfections with OCTN1, 2 or plasma membrane monoamine transporter (PMAT) small interfering RNA did not affect paeonol uptake in TR-iBRB cell lines. Upon pre-incubation of these cell lines with high glucose (HG) media, [3H]paeonol uptake decreased and mRNA expression levels of angiogenetic factors, such as hypoxia inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF) increased. However, after the pretreatment of unlabeled paeonol in HG conditions, the mRNA levels of VEGF and HIF-1 were comparatively reduced, and the [3H]paeonol uptake rate was restored. After being exposed to inflammatory conditions induced by glutamate, TNF-α, and LPS, paeonol and propranolol pretreatment significantly increased the uptake of both [3H]paeonol and [3H]propranolol in TR-iBRB cell lines compared to their respective controls. Our results demonstrate that the transport of paeonol to the retina across the iBRB may involve the proton-coupled organic cation antiporter system, and the uptake of paeonol is changed by HG conditions.
Collapse
Affiliation(s)
- Asmita Gyawali
- College of Pharmacy and Drug Information Research Institute, Sookmyung Women's University, Chungpa-dong 2-ga, Yongsan-gu, Seoul, 140-742, Republic of Korea
| | - Myung-Hee Kim
- College of Pharmacy and Drug Information Research Institute, Sookmyung Women's University, Chungpa-dong 2-ga, Yongsan-gu, Seoul, 140-742, Republic of Korea
| | - Young-Sook Kang
- College of Pharmacy and Drug Information Research Institute, Sookmyung Women's University, Chungpa-dong 2-ga, Yongsan-gu, Seoul, 140-742, Republic of Korea.
| |
Collapse
|
9
|
Police A, Shankar VK, Murthy SN. Role of Taurine Transporter in the Retinal Uptake of Vigabatrin. AAPS PharmSciTech 2020; 21:196. [PMID: 32666325 DOI: 10.1208/s12249-020-01736-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/20/2020] [Indexed: 12/18/2022] Open
Abstract
Vigabatrin (VGB) is a first-line drug used for treatment of infantile spasms. On therapeutic dose, VGB accumulates in the retina causing permanent peripheral visual field constriction. The mechanism involved in retinal accumulation of VGB is ambiguous. In the present study, mechanism of VGB transport into retina was evaluated. VGB uptake into retina was studied in vitro using human adult retinal pigment epithelial (ARPE-19) cells as a model for outer blood retinal barrier. The VGB cell uptake studies demonstrated saturation kinetics with Km value of 13.1 mM and uptake was significantly increased at pH 7.4 and hyperosmolar conditions indicating involvement of carrier-mediated Na+-Cl--dependent transporter. In the presence of taurine transporter (TauT) substrates (taurine and GABA) and inhibitor guanidinoethyl sulfonate (GES), the uptake of VGB decreased significantly demonstrating contribution of TauT. The VGB retinal levels in rats were decreased by 1.5- and 1.3-folds on chronic administration of GES and taurine, respectively. In conclusion, this study demonstrated the TauT involvement in VGB uptake and accumulation in retina.
Collapse
|
10
|
Liu X, Pan G. Roles of Drug Transporters in Blood-Retinal Barrier. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1141:467-504. [PMID: 31571172 PMCID: PMC7120327 DOI: 10.1007/978-981-13-7647-4_10] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Blood-retinal barrier (BRB) includes inner BRB (iBRB) and outer BRB (oBRB), which are formed by retinal capillary endothelial (RCEC) cells and by retinal pigment epithelial (RPE) cells in collaboration with Bruch's membrane and the choriocapillaris, respectively. Functions of the BRB are to regulate fluids and molecular movement between the ocular vascular beds and retinal tissues and to prevent leakage of macromolecules and other potentially harmful agents into the retina, keeping the microenvironment of the retina and retinal neurons. These functions are mainly attributed to absent fenestrations of RCECs, tight junctions, expression of a great diversity of transporters, and coverage of pericytes and glial cells. BRB existence also becomes a reason that systemic administration for some drugs is not suitable for the treatment of retinal diseases. Some diseases (such as diabetes and ischemia-reperfusion) impair BRB function via altering tight junctions, RCEC death, and transporter expression. This chapter will illustrate function of BRB, expressions and functions of these transporters, and their clinical significances.
Collapse
Affiliation(s)
- Xiaodong Liu
- grid.254147.10000 0000 9776 7793School of Pharmacy, China Pharmaceutical University, Nanjing, Jiangsu China
| | - Guoyu Pan
- grid.9227.e0000000119573309Shanghai Institute of Materia Medica, Chinese Academy of Science, Shanghai, Shanghai China
| |
Collapse
|
11
|
Laíns I, Chung W, Kelly RS, Gil J, Marques M, Barreto P, Murta JN, Kim IK, Vavvas DG, Miller JB, Silva R, Lasky-Su J, Liang L, Miller JW, Husain D. Human Plasma Metabolomics in Age-Related Macular Degeneration: Meta-Analysis of Two Cohorts. Metabolites 2019; 9:E127. [PMID: 31269701 PMCID: PMC6680405 DOI: 10.3390/metabo9070127] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 06/27/2019] [Accepted: 06/28/2019] [Indexed: 01/01/2023] Open
Abstract
The pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness worldwide, remains only partially understood. This has led to the current lack of accessible and reliable biofluid biomarkers for diagnosis and prognosis, and absence of treatments for dry AMD. This study aimed to assess the plasma metabolomic profiles of AMD and its severity stages with the ultimate goal of contributing to addressing these needs. We recruited two cohorts: Boston, United States (n = 196) and Coimbra, Portugal (n = 295). Fasting blood samples were analyzed using ultra-high performance liquid chromatography mass spectrometry. For each cohort, we compared plasma metabolites of AMD patients versus controls (logistic regression), and across disease stages (permutation-based cumulative logistic regression considering both eyes). Meta-analyses were then used to combine results from the two cohorts. Our results revealed that 28 metabolites differed significantly between AMD patients versus controls (false discovery rate (FDR) q-value: 4.1 × 10-2-1.8 × 10-5), and 67 across disease stages (FDR q-value: 4.5 × 10-2-1.7 × 10-4). Pathway analysis showed significant enrichment of glycerophospholipid, purine, taurine and hypotaurine, and nitrogen metabolism (p-value ≤ 0.04). In conclusion, our findings support that AMD patients present distinct plasma metabolomic profiles, which vary with disease severity. This work contributes to the understanding of AMD pathophysiology, and can be the basis of future biomarkers and precision medicine for this blinding condition.
Collapse
Affiliation(s)
- Inês Laíns
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Wonil Chung
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Rachel S Kelly
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - João Gil
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
| | - Marco Marques
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
| | - Patrícia Barreto
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Joaquim N Murta
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Ivana K Kim
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Demetrios G Vavvas
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - John B Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Rufino Silva
- Faculty of Medicine, University of Coimbra, 3000 Coimbra, Portugal
- Centro Hospitalar e Universitário de Coimbra, 3000 Coimbra, Portugal
- Association for Innovation and Biomedical Research on Light and Image, 3000 Coimbra, Portugal
| | - Jessica Lasky-Su
- Systems Genetics and Genomics Unit, Channing Division of Network Medicine Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Liming Liang
- Program in Genetic Epidemiology and Statistical Genetics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Joan W Miller
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Deeba Husain
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA 02114, USA.
| |
Collapse
|
12
|
The Effect of Drug Pre-treatment on Taurine Transport at the Inner Blood-Retinal Barrier Under Variable Conditions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1155:959-975. [DOI: 10.1007/978-981-13-8023-5_80] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
13
|
Villar-Briones A, Aird SD. Organic and Peptidyl Constituents of Snake Venoms: The Picture Is Vastly More Complex Than We Imagined. Toxins (Basel) 2018; 10:E392. [PMID: 30261630 PMCID: PMC6215107 DOI: 10.3390/toxins10100392] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/18/2018] [Accepted: 09/20/2018] [Indexed: 12/24/2022] Open
Abstract
Small metabolites and peptides in 17 snake venoms (Elapidae, Viperinae, and Crotalinae), were quantified using liquid chromatography-mass spectrometry. Each venom contains >900 metabolites and peptides. Many small organic compounds are present at levels that are probably significant in prey envenomation, given that their known pharmacologies are consistent with snake envenomation strategies. Metabolites included purine nucleosides and their bases, neurotransmitters, neuromodulators, guanidino compounds, carboxylic acids, amines, mono- and disaccharides, and amino acids. Peptides of 2⁻15 amino acids are also present in significant quantities, particularly in crotaline and viperine venoms. Some constituents are specific to individual taxa, while others are broadly distributed. Some of the latter appear to support high anabolic activity in the gland, rather than having toxic functions. Overall, the most abundant organic metabolite was citric acid, owing to its predominance in viperine and crotaline venoms, where it chelates divalent cations to prevent venom degradation by venom metalloproteases and damage to glandular tissue by phospholipases. However, in terms of their concentrations in individual venoms, adenosine, adenine, were most abundant, owing to their high titers in Dendroaspis polylepis venom, although hypoxanthine, guanosine, inosine, and guanine all numbered among the 50 most abundant organic constituents. A purine not previously reported in venoms, ethyl adenosine carboxylate, was discovered in D. polylepis venom, where it probably contributes to the profound hypotension caused by this venom. Acetylcholine was present in significant quantities only in this highly excitotoxic venom, while 4-guanidinobutyric acid and 5-guanidino-2-oxopentanoic acid were present in all venoms.
Collapse
Affiliation(s)
- Alejandro Villar-Briones
- Division of Research Support, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
| | - Steven D Aird
- Division of Faculty Affairs and Ecology and Evolution Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
| |
Collapse
|
14
|
Kubo Y, Akanuma SI, Hosoya KI. Recent advances in drug and nutrient transport across the blood-retinal barrier. Expert Opin Drug Metab Toxicol 2018; 14:513-531. [PMID: 29719158 DOI: 10.1080/17425255.2018.1472764] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION The blood-retinal barrier (BRB) is the barrier separating the blood and neural retina, and transport systems for low-weight molecules at the BRB are expected to be useful for developing drugs for the treatment of ocular neural disorders and maintaining a healthy retina. Areas covered: This review discusses blood-to-retina and retina-to-blood transport of drugs and nutrients at the BRB. In particular, P-gp (ABCB1/MDR1) has low impact on the transport of cationic drugs at the BRB, suggesting a significant role of novel organic cation transporters in influx and efflux transport of lipophilic cationic drugs between blood and the retina. The transport of pravastatin at the BRB involves transporters including organic anion transporting polypeptide 1a4 (Oatp1a4). Recent studies have shown the involvement of solute carrier transporters in the blood-to-retina transport of nutrients including riboflavin, L-ornithine, β-alanine, and L-histidine, implying that dipeptide transport at the BRB is minimal. Expert opinion: Novel organic cation transport systems and the elimination-dominant transport of pravastatin at the BRB are expected to be useful in systemic drug delivery to the neural retina without CNS side effects. The mechanism of nutrient transport at the BRB is expected to provide a new strategy for delivery of nutrient-mimetic drugs.
Collapse
Affiliation(s)
- Yoshiyuki Kubo
- a Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , Toyama , Japan
| | - Shin-Ichi Akanuma
- a Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , Toyama , Japan
| | - Ken-Ichi Hosoya
- a Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences , University of Toyama , Toyama , Japan
| |
Collapse
|
15
|
Tun T, Kang YS. Effects of simvastatin on CAT-1-mediated arginine transport and NO level under high glucose conditions in conditionally immortalized rat inner blood-retinal barrier cell lines (TR-iBRB). Microvasc Res 2017; 111:60-66. [DOI: 10.1016/j.mvr.2017.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 01/05/2017] [Accepted: 01/07/2017] [Indexed: 02/07/2023]
|
16
|
Valembois S, Krall J, Frølund B, Steffansen B. Imidazole-4-acetic acid, a new lead structure for interaction with the taurine transporter in outer blood-retinal barrier cells. Eur J Pharm Sci 2017; 103:77-84. [DOI: 10.1016/j.ejps.2017.02.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 02/27/2017] [Accepted: 02/28/2017] [Indexed: 10/20/2022]
|
17
|
Liu Y, Liu GM, Cao MJ, Chen Q, Sun L, Ji B. Potential Retinal Benefits of Dietary Polyphenols Based on Their Permeability across the Blood-Retinal Barrier. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:3179-3189. [PMID: 28362088 DOI: 10.1021/acs.jafc.7b00844] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Whether all dietary polyphenols nourish the eyes via oral supplementation is controversial. Given that passage of dietary polyphenols across the blood-retina barrier (BRB) is the precondition for polyphenols to exhibit ocular benefits, the BRB permeability of polyphenols was assessed in this study. Being common dietary polyphenols in fruits and vegetables, nonanthocyanin flavonoids, anthocyanins, and phenolic acids were investigated. BRB was simulated in vitro by using a differentiated retinal pigment epithelial cell monolayer cultivated on a Transwell culture system. Penetration rate was calculated by quantitatively analyzing the polyphenols in basolateral media. The BRB permeability of different polyphenols obviously (p < 0.05) differed, as follows: phenolic acids > nonanthocyanin flavonoids > anthocyanins. Glycosylation and methylation improved the BRB permeability of nonanthocyanin flavonoids and anthocyanins. However, instability and carbonylation at the C-4 position severely suppressed the BRB permeability of anthocyanins and nonanthocyanin flavonoids. Moreover, a new metabolite was discovered during penetration of anthocyanins into the BRB. However, hydrophilic phenolic acids exhibited better BRB permeability than hydrophobic ones. Data demonstrate that BRB permeability of polyphenols was determined based on structural characteristics, hydrophilicity, stability, and metabolic changes.
Collapse
Affiliation(s)
- Yixiang Liu
- College of Food and Biological Engineering, Jimei University , Xiamen, Fujian 361021, People's Republic of China
| | - Guang-Ming Liu
- College of Food and Biological Engineering, Jimei University , Xiamen, Fujian 361021, People's Republic of China
| | - Min-Jie Cao
- College of Food and Biological Engineering, Jimei University , Xiamen, Fujian 361021, People's Republic of China
| | - Qingchou Chen
- College of Food and Biological Engineering, Jimei University , Xiamen, Fujian 361021, People's Republic of China
| | - Lechang Sun
- College of Food and Biological Engineering, Jimei University , Xiamen, Fujian 361021, People's Republic of China
| | - Baoping Ji
- College of Food Science & Nutritional Engineering, China Agricultural University , Beijing 100083, People's Republic of China
| |
Collapse
|
18
|
Kubo Y, Akanuma SI, Hosoya KI. Impact of SLC6A Transporters in Physiological Taurine Transport at the Blood-Retinal Barrier and in the Liver. Biol Pharm Bull 2017; 39:1903-1911. [PMID: 27904033 DOI: 10.1248/bpb.b16-00597] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cumulative studies showed that taurine (2-aminoethanesulfonic acid) contributes to a variety of physiological events. Transport study suggested the cellular taurine transport in an Na+- and Cl--dependent manner, and the several members of SLC6A family have been shown as taurine transporter. At the inner blood-retinal barrier (BRB), taurine transporter (TauT/SLC6A) is involved in the transport of taurine to the retina from the circulating blood. The involvement of TauT is also suggested in γ-aminobutyric acid (GABA) transport at the inner BRB, and its role is assumed in the elimination of GABA from the retinal interstitial fluid. In the retina, taurine is thought to be a major organic osmolyte, and its influx and efflux through TauT and volume-sensitive organic osmolyte and anion channel (VSOAC) in Müller cells regulate the osmolarity in the retinal microenvironment to maintain a healthy retina. In the liver, hepatocytes take up taurine via GABA transporter 2 (GAT2/SLC6A13, the orthologue of mouse GAT3) expressed at the sinusoidal membrane of periportal hepatocytes, contributing to the metabolism of bile acid. Site-directed mutagenesis study suggests amino acid residues that are crucial in the recognition of substrates by GATs and TauT. The evidence suggests the physiological impact of taurine transporters in tissues.
Collapse
Affiliation(s)
- Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| | | | | |
Collapse
|
19
|
Kubo Y, Akanuma SI, Hosoya KI. Influx Transport of Cationic Drug at the Blood–Retinal Barrier: Impact on the Retinal Delivery of Neuroprotectants. Biol Pharm Bull 2017; 40:1139-1145. [DOI: 10.1248/bpb.b17-00090] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| | - Shin-ichi Akanuma
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| | - Ken-ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| |
Collapse
|
20
|
Rasmussen RN, Lagunas C, Plum J, Holm R, Nielsen CU. Interaction of GABA-mimetics with the taurine transporter (TauT, Slc6a6) in hyperosmotic treated Caco-2, LLC-PK1 and rat renal SKPT cells. Eur J Pharm Sci 2015; 82:138-46. [PMID: 26631583 DOI: 10.1016/j.ejps.2015.11.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/11/2015] [Accepted: 11/25/2015] [Indexed: 10/22/2022]
Abstract
The aim of the present study was to investigate if basic GABA-mimetics interact with the taurine transporter (TauT, Slc6a6), and to find a suitable cell based model that is robust towards extracellular changes in osmolality during uptake studies. Taurine uptake was measured in human Caco-2 cells, porcine LLC-PK1 cells, and rat SKPT cells using radiolabelled taurine. Hyperosmotic conditions were obtained by incubation with raffinose (final osmolality of 500mOsm) for 24h prior to the uptake experiments. Expression of the taurine transporter, TauT, was investigated at the mRNA level by real-time PCR. Uptake of the GABA-mimetics gaboxadol and vigabatrin was investigated in SKPT cells, and quantified by liquid scintillation or HPLC-MS/MS analysis, respectively. The uptake rate of [(3)H]-taurine was Na(+) and Cl(-) and concentration dependent with taurine with an apparent Vmax of 6.3±1.6pmolcm(-2)min(-1) and a Km of 24.9±15.0μM. β-alanine, nipecotic acid, gaboxadol, GABA, vigabatrin, δ-ALA and guvacine inhibited the taurine uptake rate in a concentration dependent manner. The order of affinity for TauT was β-alanine>GABA>nipecotic acid>guvacine>δ-ALA>vigabatrin>gaboxadol with IC50-values of 0.04, 1.07, 2.02, 4.19, 4.94, 31.4 and 39.9mM, respectively. In conclusion, GABA mimetics inhibited taurine uptake in hyperosmotic rat renal SKPT cells. SKPT cells, which seem to be a useful model for investigating taurine transport in the short-term presence of high concentrations of osmolytes. Furthermore, analogues of β-alanine appear to have higher affinities for TauT than GABA-analogues.
Collapse
Affiliation(s)
- Rune Nørgaard Rasmussen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark
| | - Candela Lagunas
- Drug Transporters in ADME, Department of Pharmacy, Faculty of Health and Medical Sciences, Universitetsparken 2, DK 2100, Copenhagen, Denmark
| | - Jakob Plum
- Drug Transporters in ADME, Department of Pharmacy, Faculty of Health and Medical Sciences, Universitetsparken 2, DK 2100, Copenhagen, Denmark
| | - René Holm
- Pharmaceutical Science and CMC Biologics, H. Lundbeck A/S, DK 2500, Valby, Denmark
| | - Carsten Uhd Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark.
| |
Collapse
|
21
|
Huang M, Song J, Lu B, Huang H, Chen Y, Yin W, Zhu W, Su X, Wu C, Hu H. Synthesis of taurine-fluorescein conjugate and evaluation of its retina-targeted efficiency in vitro. Acta Pharm Sin B 2014; 4:447-53. [PMID: 26579416 PMCID: PMC4629109 DOI: 10.1016/j.apsb.2014.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/09/2014] [Accepted: 10/20/2014] [Indexed: 11/11/2022] Open
Abstract
In this work, retinal penetration of fluorescein was achieved in vitro by covalent attachment of taurine to fluorescein, yielding the F–Tau conjugate. Nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS) were used to confirm the successful synthesis of F–Tau. The cellular uptake of F–Tau in adult retinal pigment epithelial cells (ARPE-19) and human retinal microvascular endothelial cells (hRMECs) was visualized via confocal scanning microscopy. The results indicated an improvement of solubility and a reduction of logP of F–Tau compared with fluorescein. As compared with fluorescein, F–Tau showed little toxicity, and was retained longer by cells in uptake experiments. F–Tau also displayed higher transepithelial permeabilities than fluorescein in ARPE-19 and hRMECs monolayer cells (P<0.05). These results showed that taurine may be a useful ligand for targeting small-molecule hydrophobic pharmaceuticals into the retina.
Collapse
|
22
|
Involvement of the carrier-mediated process in the retina-to-blood transport of spermine at the inner blood-retinal barrier. Exp Eye Res 2014; 124:17-23. [DOI: 10.1016/j.exer.2014.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/21/2014] [Accepted: 05/04/2014] [Indexed: 01/06/2023]
|
23
|
Li ZX, Yu HM, Jiang KW. Tonic GABA inhibition in hippocampal dentate granule cells: its regulation and function in temporal lobe epilepsies. Acta Physiol (Oxf) 2013; 209:199-211. [PMID: 23865761 DOI: 10.1111/apha.12148] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 05/06/2013] [Accepted: 07/12/2013] [Indexed: 01/06/2023]
Abstract
Both human and experimental evidence strongly supports the view of brain region- and cell-specific changes in tonic GABA inhibition in temporal lobe epilepsies (TLE). This 'tonic' form of signalling is not time-locked to presynaptic action potentials, which depends upon detection of ambient GABA by extrasynaptic GABAA receptors (GABAA Rs). Extrasynaptic GABAA Rs have distinct physiological and pharmacological features, including high GABA-binding affinity and low desensitization and a variety of the specific subunit combinations (α4δ-,α6δ-,α5γ-,ε-containing receptors). These features closely contribute to the function of tonic GABA current, which is preserved properly or increased in dentate gyrus in models of TLE, even in the face of a loss of synaptic inhibition and inhibitory interneurones. Markedly reduced tonic GABA inhibition may facilitate an episode of epilepsy, while persistent elevated tonic inhibition may contribute to the onset of spontaneous recurrent seizures. In dentate granule cells, tonic GABA inhibition is positively modulated by endogenous neurosteroids and other factors, which undergo changes related to hormonal status after TLE. Tonic inhibition regulates neuronal excitability through its effects on membrane potential by both offsetting the threshold and reducing the frequency of action potentials and input resistance. Therefore, extrasynaptic GABAA Rs are expected to be the most important pharmacological targets in TLE. It is likely that both elevate the ambient GABA concentration and potentiate the tonic currents, contributing to the antiepileptic effects.
Collapse
Affiliation(s)
- Z.-X. Li
- Department of Neurology; The Children's Hospital Zhejiang University School of Medicine; Hangzhou; China
| | - H.-M. Yu
- Department of Neonatology; The Children's Hospital Zhejiang University School of Medicine; Hangzhou; China
| | | |
Collapse
|
24
|
Usui T, Kubo Y, Akanuma SI, Hosoya KI. β-Alanine and l-histidine transport across the inner blood-retinal barrier: Potential involvement in l-carnosine supply. Exp Eye Res 2013; 113:135-42. [DOI: 10.1016/j.exer.2013.06.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/18/2013] [Accepted: 06/03/2013] [Indexed: 11/25/2022]
|
25
|
Jordán J, Ruíz-Moreno JM. Advances in the understanding of retinal drug disposition and the role of blood–ocular barrier transporters. Expert Opin Drug Metab Toxicol 2013; 9:1181-92. [DOI: 10.1517/17425255.2013.796928] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Joaquín Jordán
- Castilla La Mancha University, Group of Neuropharmacology,
Albacete, Spain
| | - José M Ruíz-Moreno
- Castilla La Mancha University, Department of Ophthalmology,
Albacete, Spain
- Universidad Castilla-La Mancha, Facultad de Medicina de Albacete, Departamento de Ciencias Médicas,
Avda. de Almansa, 14. 02006, Albacete, Spain ;
| |
Collapse
|
26
|
Hosoya KI, Tachikawa M. The Inner Blood-Retinal Barrier. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013. [DOI: 10.1007/978-1-4614-4711-5_4] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
27
|
Lee NY, Kang YS. The Effects of Bisphosphonates on Taurine Transport in Retinal Capillary Endothelial Cells Under High Glucose Conditions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 776:59-66. [DOI: 10.1007/978-1-4614-6093-0_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
28
|
Heim MK, Gidal BE. Vigabatrin-associated retinal damage: potential biochemical mechanisms. Acta Neurol Scand 2012; 126:219-28. [PMID: 22632110 DOI: 10.1111/j.1600-0404.2012.01684.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/23/2012] [Indexed: 12/13/2022]
Abstract
Vigabatrin (VGB), an irreversible inhibitor of gamma-aminobutyric acid (GABA) transaminase, is approved as adjunct treatment of refractory partial seizures as well as infantile spasms. Although VGB has been proven to be effective, its use is limited by the risk of retinopathy and associated peripheral visual field defects. This review describes and analyzes current literature related to potential pathophysiologic mechanisms underlying VGB-mediated cellular toxicity. Animal data suggest that GABA mediates neural excitotoxicity. The amino acid taurine is concentrated in retinal cells, and deficiency of this amino acid may be involved in VGB-mediated retinal degeneration and possible phototoxicity.
Collapse
Affiliation(s)
- M. K. Heim
- School of Pharmacy; University of Wisconsin - Madison; Madison; WI; USA
| | - B. E. Gidal
- School of Pharmacy & Department of Neurology; University of Wisconsin - Madison; Madison; WI; USA
| |
Collapse
|
29
|
Kubo Y, Fukui E, Akanuma SI, Tachikawa M, Hosoya KI. Application of Membrane Permeability Evaluated in In Vitro Analyses to Estimate Blood–Retinal Barrier Permeability. J Pharm Sci 2012; 101:2596-605. [DOI: 10.1002/jps.23171] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/02/2012] [Accepted: 04/09/2012] [Indexed: 12/31/2022]
|
30
|
Ando D, Kubo Y, Akanuma SI, Yoneyama D, Tachikawa M, Hosoya KI. Function and regulation of taurine transport in Müller cells under osmotic stress. Neurochem Int 2012; 60:597-604. [DOI: 10.1016/j.neuint.2012.02.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/16/2012] [Accepted: 02/18/2012] [Indexed: 11/26/2022]
|
31
|
Abstract
After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, including calpain, results in necrosis and apoptosis of retinal ganglion cells resulting in their degeneration. Using a systemically administered calpain inhibitor that crosses the blood-retinal barrier would provide for novel systemic intervention that protects the retina from acute injury and loss of function. Herein, we study a novel calpain peptide inhibitor, cysteic-leucyl-argininal (CYLA), in an in-vivo rat model of retinal ischemia to determine functional protection using electroretinography. The CYLA prodrug was administered intraperitoneally before and/or after ischemia-reperfusion at concentrations of 20-40 mg/kg. We found that administering 20 mg/kg of CYLA only after ischemia provides significant preservation of retinal function.
Collapse
|
32
|
Baek YY, Cho DH, Choe J, Lee H, Jeoung D, Ha KS, Won MH, Kwon YG, Kim YM. Extracellular taurine induces angiogenesis by activating ERK-, Akt-, and FAK-dependent signal pathways. Eur J Pharmacol 2011; 674:188-99. [PMID: 22130357 DOI: 10.1016/j.ejphar.2011.11.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 11/07/2011] [Accepted: 11/10/2011] [Indexed: 11/27/2022]
Abstract
Taurine, a non essential sulfur-containing amino acid, plays a critical role in cardiovascular functions. We here examined the effect of taurine on angiogenesis and its underlying signal pathway. Taurine treatment increased angiogenesis in vitro and in vivo, which was followed by activation of the phosphatidylinositol 3-kinase (PI3K)/Akt, MEK/ERK, and Src/FAK signaling pathways. Further, taurine promoted endothelial cell cycle progression to the S and G2/M phases by up-regulating the positive cell cycle proteins, particularly cyclins D1 and B, as well as down-regulating the negative cell cycle proteins, p53 and p21(WAF1/CIP1), resulting in Rb phosphorylation. This angiogenic event was inhibited by inhibitors of PI3K and MEK. In addition, a PI3K inhibitor blocked the activation of Akt and ERK, while Akt knockdown did not affect taurine-induced ERK activation, indicating that PI3K is an upstream mediator of both MEK and Akt. Taurine-induced endothelial cell migration was suppressed by Src inhibitor, but not by other inhibitors, suggesting that the increase in cell migration is regulated by Src-dependent pathway. Moreover, inhibition of cellular taurine uptake by β-alanine and taurine transporter knockdown promoted taurine-induced cell proliferation, ERK and Akt activation, and in vivo angiogenesis, suggesting that extracellular taurine induces angiogenesis. However, taurine did not induce vascular inflammation and permeability in vitro and in vivo. These data demonstrate that extracellular taurine promotes angiogenesis by Akt- and ERK-dependent cell cycle progression and Src/FAK-mediated cell migration without inducing vascular inflammation, indicating that it is potential use for the treatment of vascular dysfunction-associated human diseases.
Collapse
Affiliation(s)
- Yi-Yong Baek
- Vascular System Research Center, School of Medicine, Kangwon National University, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Song M, Salam N, Roufogalis BD, Huang T. Lycium barbarum (Goji Berry) extracts and its taurine component inhibit PPAR-γ-dependent gene transcription in human retinal pigment epithelial cells: Possible implications for diabetic retinopathy treatment. Biochem Pharmacol 2011; 82:1209-18. [DOI: 10.1016/j.bcp.2011.07.089] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 07/18/2011] [Accepted: 07/20/2011] [Indexed: 01/12/2023]
|
34
|
Hosoya KI, Tomi M, Tachikawa M. Strategies for therapy of retinal diseases using systemic drug delivery: relevance of transporters at the blood-retinal barrier. Expert Opin Drug Deliv 2011; 8:1571-87. [PMID: 22035231 DOI: 10.1517/17425247.2011.628983] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION There is an increasing need for managing rapidly progressing retinal diseases because of the potential loss of vision. Although systemic drug administration is one possible route for treating retinal diseases, retinal transfer of therapeutic drugs from the circulating blood is strictly regulated by the blood-retinal barrier (BRB). AREAS COVERED This review discusses the constraints and challenges of drug delivery to the retina. In addition, this article discusses the properties of drugs and the conditions of the BRB that affect drug permeability. The reader will gain insights into the strategies for developing therapeutic drugs that are able to cross the BRB for treating retinal diseases. Further, the reader will gain insights into the role of BRB physiology including barrier functions, and the effect of influx and efflux transporters on retinal drug delivery. EXPERT OPINION When designing and selecting optimal drug candidates, it's important to consider the fact that they should be recognized by influx transporters and that efflux transporters at the BRB should be avoided. Although lipophilic cationic drugs are known to be transported to the brain across the blood-brain barrier, verapamil transport to the retina is substantially higher than to the brain. Therefore, lipophilic cationic drugs do have a great ability to increase influx transport across the BRB.
Collapse
Affiliation(s)
- Ken-ichi Hosoya
- University of Toyama, Graduate School of Medicine and Pharmaceutical Sciences, Department of Pharmaceutics, 2630, Sugitani, Toyama 930 0194, Japan.
| | | | | |
Collapse
|
35
|
Roles of TauT and system A in cytoprotection of rat syncytiotrophoblast cell line exposed to hypertonic stress. Placenta 2010; 31:1003-9. [DOI: 10.1016/j.placenta.2010.08.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 08/07/2010] [Accepted: 08/09/2010] [Indexed: 11/19/2022]
|
36
|
Haraguchi Y, Sekine W, Shimizu T, Yamato M, Miyoshi S, Umezawa A, Okano T. Development of a new assay system for evaluating the permeability of various substances through three-dimensional tissue. Tissue Eng Part C Methods 2010; 16:685-92. [PMID: 19788345 DOI: 10.1089/ten.tec.2009.0459] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A novel assay system with cell-dense three-dimensional (3D) tissue was developed for measuring the permeability of substances. In this paper, the permeabilities of various molecules containing nutrients, a cytokine, and a chemokine were examined and analyzed. A single-layered cell sheet was approximately 20 mum thick, and as the number of layers of these cell sheets increased, so did the total thickness of the tissue. The diffusion rates of glucose and pyruvic acid were reduced to approximately 30-40% by a single-layered cell sheet compared with the control without the cell sheet, and the diffusion of both substances were completely inhibited by a quadruple-layered cell sheet. The diffusion rate of creatinin was reduced to approximately 50% and 15-20% by a single-layered and by a quintuplet-layered cell sheet, respectively. On the other hand, the diffusion rate of stromal cell-derived factor 1alpha, vascular endothelial growth factor, beta2-microglobulin, and transferrin was reduced to approximately 10%, 5%, 20%, and 10%, by only a single-layered cell sheet, respectively. The diffusion of these substances were completely inhibited by a double-layered cell sheet. These results show that the permeability of substances through 3D tissue significantly decreased with the increase of the molecular weight. Therefore, the system could give a simulated living-tissue condition for measuring the permeability of substances. To our knowledge, this is the first report about measuring the permeability of substances through cell-dense 3D tissues without scaffolds. The assay system is believed to contribute to the progress of physiology, metabology, biochemistry, and pharmacokinetics. Further, the system may give some hints for developing a new dialysis membrane technology for an artificial kidney.
Collapse
Affiliation(s)
- Yuji Haraguchi
- Institute of Advanced Biomedical Engineering and Science, TWIns, Tokyo Women's Medical University, Tokyo, Japan
| | | | | | | | | | | | | |
Collapse
|
37
|
Yahara T, Tachikawa M, Akanuma SI, Hosoya KI. Hypertonicity enhances GABA uptake by cultured rat retinal capillary endothelial cells. Drug Metab Pharmacokinet 2010; 25:611-5. [PMID: 20930424 DOI: 10.2133/dmpk.dmpk-10-nt-057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have reported previously that taurine transporter (TauT) mediates γ-aminobutyric acid (GABA) as a substrate in a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2 cells). This study investigates how TauT-mediated GABA transport is regulated in TR-iBRB2 cells under hypertonic conditions. [³H]GABA uptake by TR-iBRB2 cells exposed to 12 h- to 24 h-hypertonic culture medium was significantly greater than that of isotonic culture medium. [³H]GABA uptake by TR-iBRB2 cells was Na(+)-, Cl(-)-, and concentration-dependent with a Michaelis-Menten (K(m)) constant of 3.5 mM under isotonic conditions and K(m) of 0.324 and 5.48 mM under hypertonic conditions. Under hypertonic conditions, [³H]GABA uptake by TR-iBRB2 cells was more potently inhibited by substrates of TauT, such as taurine and β-alanine, than those of GABA transporters such as GABA, nipecotic acid, and betaine. These results suggest that an unknown high-affinity GABA transport process and TauT-mediated GABA transport are enhanced under hypertonic conditions. In conclusion, hypertonicity enhances GABA uptake by cultured rat retinal capillary endothelial cells.
Collapse
Affiliation(s)
- Tohru Yahara
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama, Japan
| | | | | | | |
Collapse
|
38
|
Tomi M, Hosoya KI. The role of blood–ocular barrier transporters in retinal drug disposition: an overview. Expert Opin Drug Metab Toxicol 2010; 6:1111-24. [DOI: 10.1517/17425255.2010.486401] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
39
|
Yoneyama D, Shinozaki Y, Lu WL, Tomi M, Tachikawa M, Hosoya KI. Involvement of system A in the retina-to-blood transport of l-proline across the inner blood–retinal barrier. Exp Eye Res 2010; 90:507-13. [DOI: 10.1016/j.exer.2010.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 01/05/2010] [Accepted: 01/05/2010] [Indexed: 10/20/2022]
|
40
|
Lysophospholipids enhance taurine release from rat retinal vascular endothelial cells under hypoosmotic stress. Microvasc Res 2009; 78:332-7. [DOI: 10.1016/j.mvr.2009.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 09/16/2009] [Accepted: 09/28/2009] [Indexed: 11/18/2022]
|
41
|
Okamoto M, Akanuma SI, Tachikawa M, Hosoya KI. Characteristics of glycine transport across the inner blood-retinal barrier. Neurochem Int 2009; 55:789-95. [PMID: 19666071 DOI: 10.1016/j.neuint.2009.08.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 07/28/2009] [Accepted: 08/01/2009] [Indexed: 10/20/2022]
Abstract
Although glycine plays a pivotal role in neurotransmission and neuromodulation in the retina and is present in high concentration in the retina, the source of retinal glycine is still unclear. The purpose of the present study was to investigate glycine transport across the inner blood-retinal barrier (inner BRB). [(14)C]Glycine transport at the inner BRB was characterized using a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2 cells) as an in vitro model of the inner BRB and in vivo vascular injection techniques. [(14)C]Glycine uptake by TR-iBRB2 cells was Na(+)- and Cl(-)-dependent, and concentration-dependent with Michaelis-Menten constants of 55.4 microM and 8.02 mM, and inhibited by glycine transporter 1 (GlyT1) and system A inhibitors. These uptake studies suggest that GlyT1 and system A are involved in [(14)C]glycine uptake by TR-iBRB2 cells. RT-PCR analysis demonstrated that GlyT1 and system A (encoding ATA 1 and ATA2) mRNA are expressed in TR-iBRB2 cells. An in vivo study suggested that [(14)C]glycine is transported from blood to the retina whereas [(14)C]alpha-methylaminoisobutyric acid, a selective substrate for system A, is not. In conclusion, GlyT1 most likely mediates glycine transport at the inner BRB and is expected to play an important role in regulating the glycine concentration in the neural retina.
Collapse
Affiliation(s)
- Masashi Okamoto
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | | | | | | |
Collapse
|
42
|
Inner blood-retinal barrier transporters: role of retinal drug delivery. Pharm Res 2009; 26:2055-65. [PMID: 19568694 DOI: 10.1007/s11095-009-9930-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 06/16/2009] [Indexed: 10/20/2022]
Abstract
The inner blood-retinal barrier (inner BRB) forms complex tight junctions of retinal capillary endothelial cells to prevent the free diffusion of substances between the circulating blood and the neural retina. Thus, understanding of the inner BRB transport mechanisms could provide a basis for the development of strategies for drug delivery to the retina. Recent progress in inner BRB research has revealed that retinal endothelial cells express a variety of unique transporters which play a role in the influx transport of essential molecules and the efflux transport of xenobiotics. In this review we focus on the transport mechanism at the inner BRB in relation to its importance in influencing the inner BRB permeability of drugs.
Collapse
|
43
|
Kang YS, Lee NY, Chung YY. The Change of Taurine Transport in Variable Stress States through the Inner Blood-Retinal Barrier using In Vitro Model. Biomol Ther (Seoul) 2009. [DOI: 10.4062/biomolther.2009.17.2.175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
|
44
|
Epidermal growth factor promotes the differentiation of stem cells derived from human umbilical cord blood into neuron-like cells via taurine induction in vitro. In Vitro Cell Dev Biol Anim 2009; 45:321-7. [DOI: 10.1007/s11626-009-9184-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 01/07/2009] [Indexed: 10/21/2022]
|
45
|
Localization of Taurine Transporter, Taurine, and Zinc in Goldfish Retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2009; 643:233-42. [DOI: 10.1007/978-0-387-75681-3_24] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
|
46
|
Hosoya KI, Fujita K, Tachikawa M. Involvement of reduced folate carrier 1 in the inner blood-retinal barrier transport of methyltetrahydrofolate. Drug Metab Pharmacokinet 2008; 23:285-92. [PMID: 18762716 DOI: 10.2133/dmpk.23.285] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The purpose of this study was to elucidate the mechanism of methyltetrahydrofolate (MTF) transport at the inner blood-retinal barrier (inner BRB). The characteristics and function of MTF transport at the inner BRB were examined using a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2) as an in vitro model of the inner BRB. The [3H]MTF uptake by TR-iBRB2 cells increased with lowering extracellular pH and was Na+- and Cl--independent. The [3H]MTF uptake was concentration-dependent with a K(m) of 5.1 microM. This process was inhibited by reduced folate carrier 1 (RFC1) substrates, such as methotrexate and formyltetrahydrofolate, in a concentration-dependent manner with an IC50 of 8.7 and 2.8 microM, respectively, suggesting that RFC1 mediates MTF uptake in TR-iBRB2 cells. Although both RFC1 and proton-coupled folate transporter (PCFT) mRNA, which are pH-sensitive folate transporters, are expressed in TR-iBRB2 cells and isolated rat retinal vascular endothelial cells, the expression level of RFC1 mRNA was 83- and 49-fold greater than that of PCFT, respectively. Taken together, the above findings are consistent with the involvement of RFC1 in the inner BRB transport of MTF.
Collapse
Affiliation(s)
- Ken-ichi Hosoya
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Japan.
| | | | | |
Collapse
|
47
|
Tomi M, Tajima A, Tachikawa M, Hosoya KI. Function of taurine transporter (Slc6a6/TauT) as a GABA transporting protein and its relevance to GABA transport in rat retinal capillary endothelial cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2138-42. [DOI: 10.1016/j.bbamem.2008.04.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Revised: 04/08/2008] [Accepted: 04/28/2008] [Indexed: 10/22/2022]
|
48
|
Cattelotte J, André P, Ouellet M, Bourasset F, Scherrmann JM, Cisternino S. In situ mouse carotid perfusion model: glucose and cholesterol transport in the eye and brain. J Cereb Blood Flow Metab 2008; 28:1449-59. [PMID: 18446168 DOI: 10.1038/jcbfm.2008.34] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The in situ mouse brain perfusion method for measuring blood-brain barrier permeability was adapted to assess transport of solutes at the blood-brain and blood-eye barriers. The procedure was checked with radiolabeled markers in oxygenated bicarbonate-buffered fluid infused for 30 to 120 sec via a carotid artery. Vascular flow estimated with diazepam was 2.2-fold lower in the eye than in the brain. The vascular volume and the integrity markers sucrose and inulin indicated that a perfusion flow rate of 2.5 mL/min preserved the physical integrity of these organs. However, the brain vasculature integrity was more sensitive to acute perfusion pressure than the eye vasculature. The functional capacities of blood barriers were assessed with D-glucose; its transport followed Michaelis-Menten kinetics with an apparent K(m) of 7.6 mmol/L and a V(max) of 23 micromol/sec per g in the brain, and a K(m) of 22.9 mmol/L and a V(max) of 40 micromol/sec per g in the eye. The transport of cholesterol to the brain and eye was significantly enhanced by adding the Abca1 inhibitor probucol, suggesting an Abca1-mediated efflux at the mouse brain and eye blood barriers. Thus in situ carotid perfusion is suitable for elucidating transport processes at the blood-brain and blood-eye barriers.
Collapse
Affiliation(s)
- Julie Cattelotte
- Department of Pharmacokinetics, Faculty of Pharmacy, INSERM U705, CNRS UMR 7157, Université Paris Descartes, Paris, France
| | | | | | | | | | | |
Collapse
|
49
|
Hosoya KI, Kyoko H, Toyooka N, Kato A, Orihashi M, Tomi M, Tachikawa M. Evaluation of Amino Acid-Mustard Transport as L-Type Amino Acid Transporter 1 (LAT1)-Mediated Alkylating Agents. Biol Pharm Bull 2008; 31:2126-30. [DOI: 10.1248/bpb.31.2126] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | | | - Atsushi Kato
- Hospital Pharmacy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
| | | | | | | |
Collapse
|
50
|
Erdamar H, Türközkan N, Ekremoğlu M, Kurt Y, Yaman H. The effect of taurine on polymorphonuclear leukocyte functions in endotoxemia. Amino Acids 2007; 33:581-5. [PMID: 17520328 DOI: 10.1007/s00726-007-0543-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2006] [Accepted: 03/03/2007] [Indexed: 10/23/2022]
Abstract
The aim of the present study was to measure MPO activity in PMN leukocytes after endotoxin administration, and to compare the levels of NO2- competing with taurine for reaction with HOCl. Furthermore we aimed to determine TauCl levels, a product of MPO-H2O2-Halide system, and to evaluate anti-inflammatory properties of PMN in endotoxemia. In addition, our second objective was to investigate the effect of taurine, an antioxidant amino acid, on anti-bactericidal and anti-inflammatory functions of PMN after administration of endotoxin together with taurine. All experiments were performed with four groups (control, taurine, endotoxemia, and taurine plus endotoxin) of ten guinea pigs. After endotoxin administration (4 mg/kg), MPO activities increased and taurine levels decreased. Therefore levels of TauCl, NO2*- increased. We observed the effects of taurine as conflicting. When taurine was administrated alone (300 mg/kg), all of these parameters decreased.Consequently, we suggested that taurine is influential in infected subjects but not on healthy ones as an antioxidative amino acid. In addition, we believe that in vivo effects of taurine may differ from those in vitro depending on its dosage.
Collapse
Affiliation(s)
- H Erdamar
- Department of Biochemistry, Faculty of Medicine, Gazi University, Ankara, Turkey
| | | | | | | | | |
Collapse
|