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Centeno D, Farsinejad S, Kochetkova E, Volpari T, Gladych-Macioszek A, Klupczynska-Gabryszak A, Polotaye T, Greenberg M, Kung D, Hyde E, Alshehri S, Pavlovic T, Sullivan W, Plewa S, Vakifahmetoglu-Norberg H, Monsma FJ, Muller PAJ, Matysiak J, Zaborowski M, DiFeo A, Norberg E, Martin LA, Iwanicki M. Modeling of Intracellular Taurine Levels Associated with Ovarian Cancer Reveals Activation of p53, ERK, mTOR and DNA-damage-sensing-dependent Cell Protection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.24.529893. [PMID: 36909636 PMCID: PMC10002676 DOI: 10.1101/2023.02.24.529893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Taurine, a non-proteogenic amino acid, and commonly used nutritional supplement can protect various tissues from degeneration associated with the action of the DNA-damaging chemotherapeutic agent cisplatin. Whether and how taurine protects human ovarian cancer (OC) cells from DNA damage caused by cisplatin is not well understood. We have found that OC ascites-derived cells contained significantly more intracellular taurine than cell cultures modeling OC. In culture, elevation of intracellular taurine concentration to OC ascites-cells-associated levels suppressed proliferation of various OC cell lines and patient-derived organoids, reduced glycolysis, and induced cell protection from cisplatin. Taurine cell protection was associated with decreased DNA damage in response to cisplatin. A combination of RNA sequencing, reverse phase protein arrays, live-cell microscopy, flow cytometry, and biochemical validation experiments provided evidence for taurine-mediated induction of mutant- or wild-type p53 binding to DNA, and activation of p53 effectors involved in negative regulation of the cell cycle (p21), and glycolysis (TIGAR). Paradoxically, taurine's suppression of cell proliferation was associated with activation of pro-mitogenic signal transduction including ERK, mTOR, and increased mRNA expression of major DNA damage sensing molecules such as DNAPK, ATM and ATR. While inhibition of ERK or p53 did not interfere with taurine's ability to protect cells from cisplatin, suppression of mTOR with Torin2, a clinically relevant inhibitor that also targets DNAPK and ATM/ATR, broke taurine's cell protection. Our studies implicate that elevation of intracellular taurine could suppress cell growth, metabolism, and activate cell protective mechanisms involving mTOR and DNA damage sensing signal transduction.
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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.
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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
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Rong Z, Li F, Zhang R, Niu S, Di X, Ni L, Liu C. Ant-Neointimal Formation Effects of SLC6A6 in Preventing Vascular Smooth Muscle Cell Proliferation and Migration via Wnt/β-Catenin Signaling. Int J Mol Sci 2023; 24:ijms24033018. [PMID: 36769341 PMCID: PMC9917619 DOI: 10.3390/ijms24033018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 02/09/2023] Open
Abstract
Vascular smooth muscle cells (VSMCs) play an important role in the pathogenesis of vascular remolding, such as atherosclerosis and restenosis. Solute carrier family 6 member 6 (SLC6A6) is a transmembrane transporter that maintains a variety of physiological functions and is highly expressed in VSMCs. However, its role on VSMCs during neointimal formation remains unknown. In this study, mRNA and protein levels of SLC6A6 were examined using models of VSMC phenotype switching in vivo and in vitro and human artery samples with or without atherosclerosis. SLC6A6 gain- and loss-of-function approaches were performed by adenovirus infection or small interfering RNA (siRNA) transfection, respectively. Reactive oxygen species (ROS), proliferation, migration, and phenotype-related proteins of VSMCs were measured. Vascular stenosis rate and related genes were assessed in a rat vascular balloon injury model overexpressing SLC6A6. SLC6A6 was downregulated in dedifferentiated VSMCs, atherosclerotic vascular tissues, and injured vascular tissues. SLC6A6 suppressed VSMC proliferation and migration, while increasing contractile VSMC proteins. Mechanistically, SLC6A6 overexpression reduced ROS production and inhibited the Wnt/β-catenin pathway. Furthermore, SLC6A6 overexpression suppressed neointimal formation in vivo. Collectively, overexpression of SLC6A6 suppresses neointimal formation by inhibiting VSMC proliferation and migration via Wnt/β-catenin signaling and maintaining the VSMC contractile phenotype.
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Affiliation(s)
| | | | | | | | | | - Leng Ni
- Correspondence: (L.N.); (C.L.); Tel.: +86-010-69152501 (L.N.); +86-010-69152500 (C.L.)
| | - Changwei Liu
- Correspondence: (L.N.); (C.L.); Tel.: +86-010-69152501 (L.N.); +86-010-69152500 (C.L.)
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Hosoya KI, Akanuma SI, Kubo Y. [Role of the Blood-Retinal Barrier Transporters: Antiaging in Retina]. YAKUGAKU ZASSHI 2021; 141:1319-1325. [PMID: 34853204 DOI: 10.1248/yakushi.21-00158-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the retina continuously receives light to enable vision, reactive oxygen species (ROS) are easily generated in neural retina. The oxidative stress induced by ROS may be involved in the onset and progression of blinding aging diseases such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Although supply of antioxidants to the retina is important to maintain the redox homeostasis in neural retina, the blood-retinal barrier (BRB) is created by complex tight-junctions of retinal capillary endothelial cells and retinal pigment epithelial cells to prevent the free diffusion of substances. The BRB is equipped with several membrane transporters to supply nutrients and essential molecules including antioxidants and drugs which exhibit antiaging effect to the retina from the circulating blood. In this review, the transporter-mediated retinal distribution of key endogenous compounds and drugs, such as vitamin C, l-cystine and gabapentin, is introduced for antiaging of the retina.
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Affiliation(s)
- Ken-Ichi Hosoya
- 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
| | - Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
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Yu MC, Wang TM, Chiou YH, Yu MK, Lin CF, Chiu CY. Urine metabolic phenotyping in children with nocturnal enuresis and comorbid neurobehavioral disorders. Sci Rep 2021; 11:16592. [PMID: 34400733 PMCID: PMC8368245 DOI: 10.1038/s41598-021-96104-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/03/2021] [Indexed: 12/16/2022] Open
Abstract
Nocturnal enuresis (NE) is a common problem among 10% school-aged children. The etiologies underlying childhood NE is complex and not fully understood nowadays. Nevertheless, increasing evidence suggests a potential link between neurobehavioral disorders and enuresis in children. In this study, we aimed to explore novel metabolomic insights into the pathophysiology of NE and also, its association with pediatric psychiatric problems. Urine collected from 41 bedwetting children and 27 healthy control children was analyzed by using 1H-nuclear magnetic resonance spectroscopy from August 2017 to December 2018. At regular follow-up, there were 14 children with refractory NE having a diagnosis of attention deficient hyperactivity disorder (ADHD) or anxiety. Eventually, we identified eight significantly differential urinary metabolites and particularly increased urinary excretion of betaine, creatine and guanidinoacetate linked to glycine, serine and threonine metabolism were associated with a comorbidity of neurobehavioral disorders in refractory bedwetting children. Notably, based on physiological functions of betaine acting as a renal osmolyte and methyl group donor, we speculated its potential role in modulation of renal and/or central circadian clock systems, becoming a useful urinary metabolic marker in diagnosis of treatment-resistant NE in children affected by these two disorders.
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Affiliation(s)
- Mei-Ching Yu
- Division of Pediatric Nephrology, Department of Pediatrics, Lin-Kou Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, 5, Fusing Street, Gueishan, Taoyuan, 333, Taiwan.
| | - Ta-Min Wang
- Division of Pediatric Urology, Department of Urology, Lin-Kou Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yee-Hsuan Chiou
- Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Meng-Kung Yu
- Department of Pediatrics, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
| | - Chiao-Fan Lin
- Department of Child and Adolescent Psychiatry, Lin-Kou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chih-Yung Chiu
- Division of Pediatric Pulmonology, Department of Pediatrics, Clinical Metabolomics Core Laboratory, Lin-Kou Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, 5, Fusing Street, Gueishan, Taoyuan, 333, Taiwan.
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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.
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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.
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Netti V, Pizzoni A, Pérez-Domínguez M, Ford P, Pasantes-Morales H, Ramos-Mandujano G, Capurro C. Release of taurine and glutamate contributes to cell volume regulation in human retinal Müller cells: differences in modulation by calcium. J Neurophysiol 2018; 120:973-984. [PMID: 29790838 DOI: 10.1152/jn.00725.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuronal activity in the retina generates osmotic gradients that lead to Müller cell swelling, followed by a regulatory volume decrease (RVD) response, partially due to the isoosmotic efflux of KCl and water. However, our previous studies in a human Müller cell line (MIO-M1) demonstrated that an important fraction of RVD may also involve the efflux of organic solutes. We also showed that RVD depends on the swelling-induced Ca2+ release from intracellular stores. Here we investigate the contribution of taurine (Tau) and glutamate (Glu), the most relevant amino acids in Müller cells, to RVD through the volume-regulated anion channel (VRAC), as well as their Ca2+ dependency in MIO-M1 cells. Swelling-induced [3H]Tau/[3H]Glu release was assessed by radiotracer assays and cell volume by fluorescence videomicroscopy. Results showed that cells exhibited an osmosensitive efflux of [3H]Tau and [3H]Glu (Tau > Glu) blunted by VRAC inhibitors 4-(2-butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl)-oxybutyric acid and carbenoxolone reducing RVD. Only [3H]Tau efflux was mainly dependent on Ca2+ release from intracellular stores. RVD was unaffected in a Ca2+-free medium, probably due to Ca2+-independent Tau and Glu release, but was reduced by chelating intracellular Ca2+. The inhibition of phosphatidylinositol-3-kinase reduced [3H]Glu efflux but also the Ca2+-insensitive [3H]Tau fraction and decreased RVD, providing evidence of the relevance of this Ca2+-independent pathway. We propose that VRAC-mediated Tau and Glu release has a relevant role in RVD in Müller cells. The observed disparities in Ca2+ influence on amino acid release suggest the presence of VRAC isoforms that may differ in substrate selectivity and regulatory mechanisms, with important implications for retinal physiology. NEW & NOTEWORTHY The mechanisms for cell volume regulation in retinal Müller cells are still unknown. We show that swelling-induced taurine and glutamate release mediated by the volume-regulated anion channel (VRAC) largely contributes the to the regulatory volume decrease response in a human Müller cell line. Interestingly, the hypotonic-induced efflux of these amino acids exhibits disparities in Ca2+-dependent and -independent regulatory mechanisms, which strongly suggests that Müller cells may express different VRAC heteromers formed by the recently discovered leucine-rich repeat containing 8 (LRRC8) proteins.
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Affiliation(s)
- Vanina Netti
- Universidad de Buenos Aires, Facultad de Medicina. Departamento de Ciencias Fisiológicas, Laboratorio de Biomembranas , Buenos Aires , Argentina.,CONICET-Universidad de Buenos Aires. Instituto de Fisiología y Biofísica "Bernardo Houssay," Buenos Aires, Argentina
| | - Alejandro Pizzoni
- Universidad de Buenos Aires, Facultad de Medicina. Departamento de Ciencias Fisiológicas, Laboratorio de Biomembranas , Buenos Aires , Argentina.,CONICET-Universidad de Buenos Aires. Instituto de Fisiología y Biofísica "Bernardo Houssay," Buenos Aires, Argentina
| | - Martha Pérez-Domínguez
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Paula Ford
- Universidad de Buenos Aires, Facultad de Medicina. Departamento de Ciencias Fisiológicas, Laboratorio de Biomembranas , Buenos Aires , Argentina.,CONICET-Universidad de Buenos Aires. Instituto de Fisiología y Biofísica "Bernardo Houssay," Buenos Aires, Argentina
| | - Herminia Pasantes-Morales
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Gerardo Ramos-Mandujano
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Claudia Capurro
- Universidad de Buenos Aires, Facultad de Medicina. Departamento de Ciencias Fisiológicas, Laboratorio de Biomembranas , Buenos Aires , Argentina.,CONICET-Universidad de Buenos Aires. Instituto de Fisiología y Biofísica "Bernardo Houssay," Buenos Aires, Argentina
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8
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Dayang W, Dongbo P. Osmolyte taurine induction in UVA exposed human retinal pigment epithelial cells. Cutan Ocul Toxicol 2018; 37:338-343. [PMID: 29658345 DOI: 10.1080/15569527.2018.1465078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AIM To explore the osmolytes expression in ultraviolet (UVA) stressed human retinal pigment epithelial cells. METHODS Osmolyte transporters and vascular endothelial growth factor (VEGF) messenger RNA (mRNA) were determined by real time polymerase chain reaction (PCR). Osmolyte uptake was measured by radioimmunoassay. VEGF concentrations were determined by immunoassay and enzyme-linked immunosorbent assay (ELISA). Osmolyte taurine transporter (TAUT) were silenced by siRNA technology. RESULTS Hypertonicity accelerated osmolyte betaine uptake, myoinositol uptake, and taurine uptake, compared to normotonic stress. UVA irradiation also accelerated osmolyte transporters expression and osmolytes uptake. Especially, osmolyte taurine remarkably inhibited VEGF release induced by UVA irradiation. VEGF in the UVA stressed retinal pigment epithelial cell supernatant was accumulated slow after taurine preincubation. VEGF expression increased significantly in UVA-stressed cells after TAUT silencing. Moreover, taurine reduced the VEGF level in human ocular aqueous humor. CONCLUSION The inhibition of VEGF by osmolyte taurine plays the crucial role in retina adaption to UVA irradiation.
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Affiliation(s)
- Wu Dayang
- a Department of Ophthalmology , The First Affiliated Hospital of Jinzhou Medical University , Jinzhou , P.R. China
| | - Pang Dongbo
- a Department of Ophthalmology , The First Affiliated Hospital of Jinzhou Medical University , Jinzhou , P.R. China
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Bruździak P, Panuszko A, Kaczkowska E, Piotrowski B, Daghir A, Demkowicz S, Stangret J. Taurine as a water structure breaker and protein stabilizer. Amino Acids 2018; 50:125-140. [PMID: 29043510 PMCID: PMC5762795 DOI: 10.1007/s00726-017-2499-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/26/2017] [Indexed: 12/24/2022]
Abstract
The enhancing effect on the water structure has been confirmed for most of the osmolytes exhibiting both stabilizing and destabilizing properties in regard to proteins. The presented work concerns osmolytes, which should be classified as "structure breaking" solutes: taurine and N,N,N-trimethyltaurine (TMT). Here, we combine FTIR spectroscopy, DSC calorimetry and DFT calculations to gain an insight into the interactions between osmolytes and two proteins: lysozyme and ubiquitin. Despite high structural similarity, both osmolytes exert different influence on protein stability: taurine is a stabilizer, TMT is a denaturant. We show also that taurine amino group interacts directly with the side chains of proteins, whereas TMT does not interact with proteins at all. Although two solutes weaken on average the structure of the surrounding water, their hydration spheres are different. Taurine is surrounded by two populations of water molecules: bonded with weak H-bonds around sulfonate group, and strongly bonded around amino group. The strong hydrogen-bonded network of water molecules around the amino group of taurine further improves properties of enhanced protein hydration sphere and stabilizes the native protein form. Direct interactions of this group with surface side chains provide a proper orientation of taurine and prevents the [Formula: see text] group from negative influence. The weakened [Formula: see text] hydration sphere of TMT breaks up the hydrogen-bonded network of water around the protein and destabilizes it. However, TMT at low concentration stabilize both proteins to a small extent. This effect can be attributed to an actual osmophobic effect which is overcome if the concentration increases.
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Affiliation(s)
- P Bruździak
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland.
| | - A Panuszko
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland
| | - E Kaczkowska
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland
| | - B Piotrowski
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland
| | - A Daghir
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland
| | - S Demkowicz
- Department of Organic Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland
| | - J Stangret
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233, Gdańsk, Poland
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Dayang W, Dongbo P. Taurine prevents ultraviolet B induced apoptosis in retinal ganglion cells. Cutan Ocul Toxicol 2017; 37:90-95. [PMID: 28592159 DOI: 10.1080/15569527.2017.1339714] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Wu Dayang
- Department of Ophthalmology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, PR China
| | - Pang Dongbo
- Department of Ophthalmology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, PR China
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Netti V, Fernández J, Kalstein M, Pizzoni A, Di Giusto G, Rivarola V, Ford P, Capurro C. TRPV4 Contributes to Resting Membrane Potential in Retinal Müller Cells: Implications in Cell Volume Regulation. J Cell Biochem 2017; 118:2302-2313. [PMID: 28098409 DOI: 10.1002/jcb.25884] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/13/2017] [Indexed: 11/10/2022]
Abstract
Neural activity alters osmotic gradients favoring cell swelling in retinal Müller cells. This swelling is followed by a regulatory volume decrease (RVD), partially mediated by an efflux of KCl and water. The transient receptor potential channel 4 (TRPV4), a nonselective calcium channel, has been proposed as a candidate for mediating intracellular Ca2+ elevation induced by swelling. We previously demonstrated in a human Müller cell line (MIO-M1) that RVD strongly depends on ion channel activation and, consequently, on membrane potential (Vm ). The aim of this study was to investigate if Ca2+ influx via TRPV4 contributes to RVD by modifying intracellular Ca2+ concentration and/or modulating Vm in MIO-M1 cells. Cell volume, intracellular Ca2+ levels, and Vm changes were evaluated using fluorescent probes. Results showed that MIO-M1 cells express functional TRPV4 which determines the resting Vm associated with K+ channels. Swelling-induced increases in Ca2+ levels was due to both Ca2+ release from intracellular stores and Ca2+ influx by a pathway alternative to TRPV4. TRPV4 blockage affected swelling-induced biphasic response (depolarization-repolarization), suggesting its participation in modulating Vm changes during RVD. Agonist stimulation of Ca2+ influx via TRPV4 activated K+ channels hyperpolarizing Vm and accelerating RVD. We propose that TRPV4 forms a signaling complex with Ca2+ and/or voltage-dependent K+ channels to define resting Vm and Vm changes during RVD. TRPV4 involvement in RVD depends on the type of stimuli and/or degree of channel activation, leading to a maximum RVD response when Ca2+ influx overcomes a threshold and activates further signaling pathways in cell volume regulation. J. Cell. Biochem. 118: 2302-2313, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Vanina Netti
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Juan Fernández
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Maia Kalstein
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro Pizzoni
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gisela Di Giusto
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Valeria Rivarola
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula Ford
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Claudia Capurro
- Laboratorio de Biomembranas, IFIBIO Houssay, CONICET-UBA, Departamento de Ciencia Fisiológicas, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
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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: 14] [Impact Index Per Article: 2.0] [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.
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Affiliation(s)
- Yoshiyuki Kubo
- Department of Pharmaceutics, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
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Kofler M, Schiefecker A, Ferger B, Beer R, Sohm F, Broessner G, Hackl W, Rhomberg P, Lackner P, Pfausler B, Thomé C, Schmutzhard E, Helbok R. Cerebral Taurine Levels are Associated with Brain Edema and Delayed Cerebral Infarction in Patients with Aneurysmal Subarachnoid Hemorrhage. Neurocrit Care 2015; 23:321-9. [DOI: 10.1007/s12028-015-0140-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Dayang W, Jinsong Z. Taurine inhibits interleukin-6 expression and release induced by ultraviolet B exposure to human retinal pigment epithelium cells. Cutan Ocul Toxicol 2014; 34:189-94. [PMID: 25198400 DOI: 10.3109/15569527.2014.944649] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The massive uptake of compatible osmolytes is a self-protective response shared by retina exposed to hypertonic stress and ultraviolet stress. OBJECTIVE This study aimed to investigate the protective effects of taurine against ultraviolet damage in human retinal pigment epithelium cells. METHODS Real-time PCR, radioimmunoassay, ELISA and immunoassay were used to measure osmolyte uptake and IL-6 expression. RESULTS Compared with normotonic stress, hypertonic stress led to an induction of osmolyte uptake including betaine, myoinositol and taurine. UVB exposure upregulated osmolyte transporter mRNA expression and increased osmolyte uptake respectively. Especially, taurine suppressed UVB-induced IL-6 mRNA expression significantly. The accumulation of IL-6 in UVB-exposed human retinal pigment epithelial cells supernatant was much slower when the cells were preincubated with taurine. Moreover, taurine suppressed IL-6 concentration in aqueous humour. CONCLUSION The effect of compatible osmolyte taurine on IL-6 expression and release may play an important role in cell resistance and adaption to UVB exposure.
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Affiliation(s)
- Wu Dayang
- Department of Ophthalmology, The First Affiliated Hospital of Liaoning Medical University , Jinzhou , P.R. China and
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Qian T, Chen R, Nakamura M, Furukawa T, Kumada T, Akita T, Kilb W, Luhmann HJ, Nakahara D, Fukuda A. Activity-dependent endogenous taurine release facilitates excitatory neurotransmission in the neocortical marginal zone of neonatal rats. Front Cell Neurosci 2014; 8:33. [PMID: 24574969 PMCID: PMC3918584 DOI: 10.3389/fncel.2014.00033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 01/22/2014] [Indexed: 12/27/2022] Open
Abstract
In the developing cerebral cortex, the marginal zone (MZ), consisting of early-generated neurons such as Cajal-Retzius cells, plays an important role in cell migration and lamination. There is accumulating evidence of widespread excitatory neurotransmission mediated by γ-aminobutyric acid (GABA) in the MZ. Cajal-Retzius cells express not only GABAA receptors but also α2/β subunits of glycine receptors, and exhibit glycine receptor-mediated depolarization due to high [Cl−]i. However, the physiological roles of glycine receptors and their endogenous agonists during neurotransmission in the MZ are yet to be elucidated. To address this question, we performed optical imaging from the MZ using the voltage-sensitive dye JPW1114 on tangential neocortical slices of neonatal rats. A single electrical stimulus evoked an action-potential-dependent optical signal that spread radially over the MZ. The amplitude of the signal was not affected by glutamate receptor blockers, but was suppressed by either GABAA or glycine receptor antagonists. Combined application of both antagonists nearly abolished the signal. Inhibition of Na+, K+-2Cl− cotransporter by 20 µM bumetanide reduced the signal, indicating that this transporter contributes to excitation. Analysis of the interstitial fluid obtained by microdialysis from tangential neocortical slices with high-performance liquid chromatography revealed that GABA and taurine, but not glycine or glutamate, were released in the MZ in response to the electrical stimulation. The ambient release of taurine was reduced by the addition of a voltage-sensitive Na+ channel blocker. Immunohistochemistry and immunoelectron microscopy indicated that taurine was stored both in Cajal-Retzius and non-Cajal-Retzius cells in the MZ, but was not localized in presynaptic structures. Our results suggest that activity-dependent non-synaptic release of endogenous taurine facilitates excitatory neurotransmission through activation of glycine receptors in the MZ.
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Affiliation(s)
- Taizhe Qian
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Rongqing Chen
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Germany
| | - Masato Nakamura
- Department of Psychology and Behavioral Neuroscience, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Tomonori Furukawa
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Tatsuro Kumada
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan ; Department of Occupational Therapy, Tokoha University Hamamatsu, Japan
| | - Tenpei Akita
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg-University Mainz, Germany
| | - Daiichiro Nakahara
- Department of Psychology and Behavioral Neuroscience, Hamamatsu University School of Medicine Hamamatsu, Japan
| | - Atsuo Fukuda
- Department of Neurophysiology, Hamamatsu University School of Medicine Hamamatsu, Japan
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Sava BA, Chen R, Sun H, Luhmann HJ, Kilb W. Taurine activates GABAergic networks in the neocortex of immature mice. Front Cell Neurosci 2014; 8:26. [PMID: 24550782 PMCID: PMC3912439 DOI: 10.3389/fncel.2014.00026] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/17/2014] [Indexed: 02/05/2023] Open
Abstract
Although it has been suggested that taurine is the main endogenous neurotransmitter acting on glycine receptors, the implications of glycine receptor-mediated taurine actions on immature neocortical networks have not been addressed yet. To investigate the influence of taurine on the excitability of neuronal networks in the immature neocortex, we performed whole-cell patch-clamp recordings from visually identified pyramidal neurons and interneurons in coronal slices from C57Bl/6 and GAD67-green fluorescent protein (GFP) transgenic mice (postnatal days 2–4). In 46% of the pyramidal neurons bath-application of taurine at concentrations ≥ 300 μM significantly enhanced the frequency of postsynaptic currents (PSCs) by 744.3 ± 93.8% (n = 120 cells). This taurine-induced increase of PSC frequency was abolished by 0.2 μM tetrodotoxin (TTX), 1 μM strychnine or 3 μM gabazine, but was unaffected by the glutamatergic antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and (±) R(-)-3-(2-carboxypiperazine-4-yl)-propyl-1-phosphonic acid (CPP), suggesting that taurine specifically activates GABAergic network activity projecting to pyramidal neurons. Cell-attached recordings revealed that taurine enhanced the frequency of action potentials (APs) in pyramidal neurons, indicating an excitatory action of the GABAergic PSCs. In order to identify the presynaptic targets of taurine we demonstrate that bath application of taurine induced in GAD67-GFP labeled interneurons an inward current that is mainly mediated by glycine receptors and can generate APs in these cells. We conclude from these results that taurine can enhance network excitability in the immature neocortex by selectively activating GABAergic interneurons via interactions with glycine receptors.
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Affiliation(s)
- Bogdan A Sava
- Institute of Physiology, University Medical Center Mainz Mainz, Germany
| | - Rongqing Chen
- Institute of Physiology, University Medical Center Mainz Mainz, Germany
| | - Haiyan Sun
- Institute of Physiology, University Medical Center Mainz Mainz, Germany
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center Mainz Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center Mainz Mainz, Germany
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Kilb W, Kirischuk S, Luhmann HJ. Role of tonic GABAergic currents during pre- and early postnatal rodent development. Front Neural Circuits 2013; 7:139. [PMID: 24027498 PMCID: PMC3760143 DOI: 10.3389/fncir.2013.00139] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/16/2013] [Indexed: 11/13/2022] Open
Abstract
In the last three decades it became evident that the GABAergic system plays an essential role for the development of the central nervous system, by influencing the proliferation of neuronal precursors, neuronal migration and differentiation, as well as by controlling early activity patterns and thus formation of neuronal networks. GABA controls neuronal development via depolarizing membrane responses upon activation of ionotropic GABA receptors. However, many of these effects occur before the onset of synaptic GABAergic activity and thus require the presence of extrasynaptic tonic currents in neuronal precursors and immature neurons. This review summarizes our current knowledge about the role of tonic GABAergic currents during early brain development. In this review we compare the temporal sequence of the expression and functional relevance of different GABA receptor subunits, GABA synthesizing enzymes and GABA transporters. We also refer to other possible endogenous agonists of GABAA receptors. In addition, we describe functional consequences mediated by the GABAergic system during early developmental periods and discuss current models about the origin of extrasynaptic GABA and/or other endogenous GABAergic agonists during early developmental states. Finally, we present evidence that tonic GABAergic activity is also critically involved in the generation of physiological as well as pathophysiological activity patterns before and after the establishment of functional GABAergic synaptic connections.
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Affiliation(s)
- Werner Kilb
- Institute of Physiology and Pathophysiology, University Medical Center, Johannes Gutenberg University Mainz, Germany
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Reichenbach A, Bringmann A. New functions of Müller cells. Glia 2013; 61:651-78. [PMID: 23440929 DOI: 10.1002/glia.22477] [Citation(s) in RCA: 462] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/10/2012] [Indexed: 12/12/2022]
Abstract
Müller cells, the major type of glial cells in the retina, are responsible for the homeostatic and metabolic support of retinal neurons. By mediating transcellular ion, water, and bicarbonate transport, Müller cells control the composition of the extracellular space fluid. Müller cells provide trophic and anti-oxidative support of photoreceptors and neurons and regulate the tightness of the blood-retinal barrier. By the uptake of glutamate, Müller cells are more directly involved in the regulation of the synaptic activity in the inner retina. This review gives a survey of recently discoved new functions of Müller cells. Müller cells are living optical fibers that guide light through the inner retinal tissue. Thereby they enhance the signal/noise ratio by minimizing intraretinal light scattering and conserve the spatial distribution of light patterns in the propagating image. Müller cells act as soft, compliant embedding for neurons, protecting them in case of mechanical trauma, and also as soft substrate required for neurite growth and neuronal plasticity. Müller cells release neuroactive signaling molecules which modulate neuronal activity, are implicated in the mediation of neurovascular coupling, and mediate the homeostasis of the extracellular space volume under hypoosmotic conditions which are a characteristic of intense neuronal activity. Under pathological conditions, a subset of Müller cells may differentiate to neural progenitor/stem cells which regenerate lost photoreceptors and neurons. Increasing knowledge of Müller cell function and responses in the normal and diseased retina will have great impact for the development of new therapeutic approaches for retinal diseases.
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Affiliation(s)
- Andreas Reichenbach
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany.
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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]
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