1
|
Fibbi B, Marroncini G, Anceschi C, Naldi L, Peri A. Hyponatremia and Oxidative Stress. Antioxidants (Basel) 2021; 10:1768. [PMID: 34829639 PMCID: PMC8614907 DOI: 10.3390/antiox10111768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/26/2021] [Accepted: 11/03/2021] [Indexed: 12/15/2022] Open
Abstract
Hyponatremia, i.e., the presence of a serum sodium concentration ([Na+]) < 136 mEq/L, is the most frequent electrolyte imbalance in the elderly and in hospitalized patients. Symptoms of acute hyponatremia, whose main target is the central nervous system, are explained by the "osmotic theory" and the neuronal swelling secondary to decreased extracellular osmolality, which determines cerebral oedema. Following the description of neurological and systemic manifestations even in mild and chronic hyponatremia, in the last decade reduced extracellular [Na+] was associated with detrimental effects on cellular homeostasis independently of hypoosmolality. Most of these alterations appeared to be elicited by oxidative stress. In this review, we focus on the role of oxidative stress on both osmolality-dependent and -independent impairment of cell and tissue functions observed in hyponatremic conditions. Furthermore, basic and clinical research suggested that oxidative stress appears to be a common denominator of the degenerative processes related to aging, cancer progression, and hyponatremia. Of note, low [Na+] is able to exacerbate multiple manifestations of senescence and to decrease progression-free and overall survival in oncologic patients.
Collapse
Affiliation(s)
- Benedetta Fibbi
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Giada Marroncini
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Cecilia Anceschi
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Laura Naldi
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| | - Alessandro Peri
- Pituitary Diseases and Sodium Alterations Unit, AOU Careggi, 50139 Florence, Italy; (B.F.); (G.M.)
- Endocrinology, Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, AOU Careggi, 50139 Florence, Italy; (C.A.); (L.N.)
| |
Collapse
|
2
|
Lee S, Nagata F, Kato K, Kasuga T, Nakano T. Development of orthophosphosilicate glass/poly(lactic acid) composite anisotropic scaffolds for simultaneous reconstruction of bone quality and quantity. J Biomed Mater Res A 2021; 109:788-803. [PMID: 32720351 PMCID: PMC7984230 DOI: 10.1002/jbm.a.37067] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/16/2020] [Accepted: 07/19/2020] [Indexed: 01/03/2023]
Abstract
Reconstruction of organ-specific architecture is necessary to recover the original organ function. The anisotropic structure of bone tissue is strongly related to the collagen fibril alignment and bone apatite crystal direction. Bone regeneration indicates following two main process; first, restoration of bone mineral density (BMD; bone quantity), and second, restoring bone apatite c-axis orientation (bone quality). In addition to BMD, bone quality is the most important factor among bone mechanical properties. Recovery of the original bone function requires development of novel scaffolds with simultaneous reconstruction of bone quality and quantity. Herein, novel orthophosphosilicate glass (PSG)/poly(lactic acid) composite anisotropic scaffolds were developed to control cell alignment and enhance bone formation, which are important for the simultaneous reconstruction of bone quality and quantity. The strategy to control cell alignment and bone formation involved designing anisotropic scaffolds in combination with the release of therapeutic ions by PSGs. The morphology of fibrous scaffolds containing PSGs was quantitatively designed using electrospinning. This successfully modulated cell alignment and subsequent bone apatite c-axis orientation along the fiber-oriented direction. The released silicate and Mg2+ ions from PSGs in scaffolds improved cell adhesion, proliferation, and calcification. To best of our knowledge, this is the first report demonstrating that the anisotropic scaffolds containing bioactive glasses regenerate bone tissues with simultaneous reconstruction of bone quality and quantity via stimulating osteoblasts by inorganic ions and designing morphology of scaffolds.
Collapse
Affiliation(s)
- Sungho Lee
- National Institute of Advanced Industrial Science and Technology (AIST)NagoyaJapan
- Division of Materials and Manufacturing Science, Graduate School of EngineeringOsaka UniversityOsakaJapan
| | - Fukue Nagata
- National Institute of Advanced Industrial Science and Technology (AIST)NagoyaJapan
| | - Katsuya Kato
- National Institute of Advanced Industrial Science and Technology (AIST)NagoyaJapan
| | - Toshihiro Kasuga
- Division of Advanced Ceramics, Graduate School of EngineeringNagoya Institute of TechnologyNagoyaJapan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of EngineeringOsaka UniversityOsakaJapan
| |
Collapse
|
3
|
Fiorani M, Scotti M, Guidarelli A, Burattini S, Falcieri E, Cantoni O. SVCT2-Dependent plasma and mitochondrial membrane transport of ascorbic acid in differentiating myoblasts. Pharmacol Res 2020; 159:105042. [PMID: 32580031 DOI: 10.1016/j.phrs.2020.105042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022]
Abstract
The Na+-dependent Vitamin C transporter 2 (SVCT2) is expressed in the plasma and mitochondrial membranes of various cell types. This notion was also established in proliferating C2C12 myoblasts (Mb), in which the transporter was characterised by a high and low affinity in the plasma and mitochondrial membranes, respectively. In addition, the mitochondrial expression of SVCT2 appeared particularly elevated and, consistently, a brief pre-exposure to low concentrations of Ascorbic Acid (AA) abolished mitochondrial superoxide formation selectively induced by the cocktail arsenite/ATP. Early myotubes (Mt) derived from these cells after 4 days of differentiation presented evidence of slightly increased SVCT2 expression, and were characterised by kinetic parameters for plasma membrane transport of AA in line with those detected in Mb. Confocal microscopy studies indicated that the mitochondrial expression of SVCT2 is well preserved in Mt with one or two nuclei, but progressively reduced in Mt with three or more nuclei. Cellular and mitochondrial expression of SVCT2 was found reduced in day 7 Mt. While the uptake studies were compromised by the poor purity of the mitochondrial preparations obtained from day 4 Mt, we nevertheless obtained evidence of poor transport of the vitamin using the same functional studies successfully employed with Mb. Indeed, even greater concentrations of/longer pre-exposure to AA failed to induce scavenging of mitochondrial superoxide in Mt. These results are therefore indicative of a severely reduced mitochondrial uptake of the vitamin in early Mt, attributable to decreased expression as well as impaired activity of mitochondrial SVCT2.
Collapse
Affiliation(s)
- Mara Fiorani
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Maddalena Scotti
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Andrea Guidarelli
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Sabrina Burattini
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Elisabetta Falcieri
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Orazio Cantoni
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| |
Collapse
|
4
|
Ye J, Li B, Li M, Zheng Y, Wu S, Han Y. ROS induced bactericidal activity of amorphous Zn-doped titanium oxide coatings and enhanced osseointegration in bacteria-infected rat tibias. Acta Biomater 2020; 107:313-324. [PMID: 32126308 DOI: 10.1016/j.actbio.2020.02.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/11/2020] [Accepted: 02/24/2020] [Indexed: 10/24/2022]
Abstract
Titanium-based endosseous implants with high antibacterial and osseointegration activities are extremely required in clinics. To achieve this line, herein the doped coatings with three kinds of Zn doses were micro-arc oxidized (MAOed) on Ti. They were examined to reveal a bilayered structure, in which the outer layer consisted completely of the amorphism comprising elements of Ti, O and Zn with Zn doped in the form of weaken Zn-O bonds, and the underlying layer was partially crystallized with nanocrystalline TiO2 and Zn2TiO4 to embed an amorphous matrix. While the Zn doped doses of the surface amorphous layers increased with elevating the MAOed voltages, the weaken Zn-O bonds in the amorphism were identified to act as both the contributor of Zn2+ controllable release and the generator of reactive oxide species (ROS) on the coatings. The enhanced HO• and O2-• formation on the elevated voltage MAOed coatings caused serious break of the cell walls and plasma membranes of S. aureus. In parallel, the enhanced Zn2+ release and extracellular H2O2 formation led to the enhanced intracellular ROS level of S. aureus, further aggravating the damage of plasma membrane, resulting in bacteria death. On contrary to the overdose of Zn doped coating, the moderate doses of Zn doped coatings did not induce additional intracellular ROS and attenuate viability and proliferation of osteoblasts in vitro, and promoted osseointegration in both S. aureus-uninfected and infected rat tibias, which ascribed to the strong antibacterial activity and un-attenuated cell function of the coatings in the infected case. STATEMENT OF SIGNIFICANCE: (1) The Zn-doped coatings revealed a bilayered structure of the surface layer comprising the Ti, O and Zn constructed amorphism with Zn in the form of weaken Zn-O bonds, and the underlying layer comprising nanocrystalline TiO2 and Zn2TiO4 to embed amorphous matrix. (2) The weaken Zn-O bonds in the amorphism were identified to act as both the contributor of Zn2+ controllable release and the generator of ROS on the coatings. (3) The enhanced Zn2+ release and ROS formation on the coatings killed S. aureus by inducing serious break of their cell walls and plasma membranes. This effect in combination of un-attenuated osteoblast proliferation endowed the moderate Zn doped coatings with enhanced osseointegration in S. aureus-infected rat tibias.
Collapse
|
5
|
DePhillipo NN, Aman ZS, Kennedy MI, Begley JP, Moatshe G, LaPrade RF. Efficacy of Vitamin C Supplementation on Collagen Synthesis and Oxidative Stress After Musculoskeletal Injuries: A Systematic Review. Orthop J Sports Med 2018; 6:2325967118804544. [PMID: 30386805 PMCID: PMC6204628 DOI: 10.1177/2325967118804544] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Background Recent investigations on the biochemical pathways after a musculoskeletal injury have suggested that vitamin C (ascorbic acid) may be a viable supplement to enhance collagen synthesis and soft tissue healing. Purpose To (1) summarize vitamin C treatment protocols; (2) report on the efficacy of vitamin C in accelerating healing after bone, tendon, and ligament injuries in vivo and in vitro; and (3) report on the efficacy of vitamin C as an antioxidant protecting against fibrosis and promoting collagen synthesis. Study Design Systematic review; Level of evidence, 2. Methods A systematic review was performed, with the inclusion criteria of animal and human studies on vitamin C supplementation after a musculoskeletal injury specific to collagen cross-linking, collagen synthesis, and biologic healing of the bone, ligament, and tendon. Results The initial search yielded 286 articles. After applying the inclusion and exclusion criteria, 10 articles were included in the final analysis. Of the preclinical studies evaluating fracture healing, 2 studies reported significantly accelerated bone healing in the vitamin C supplementation group compared with control groups. The 2 preclinical studies evaluating tendon healing reported significant increases in type I collagen fibers and scar tissue formation with vitamin C compared with control groups. The 1 preclinical study after anterior cruciate ligament (ACL) reconstruction reported significant short-term (1-6 weeks) improvements in ACL graft incorporation in the vitamin C group compared with control groups; however, there was no long-term (42 weeks) difference. Of the clinical studies evaluating fracture healing, 1 study reported no significant differences in the rate of fracture healing at 50 days or functional outcomes at 1 year. Vitamin C supplementation was shown to decrease oxidative stress parameters by neutralizing reactive oxygen species through redox modulation in animal models. No animal or human studies reported any adverse effects of vitamin C supplementation. Conclusion Preclinical studies demonstrated that vitamin C has the potential to accelerate bone healing after a fracture, increase type I collagen synthesis, and reduce oxidative stress parameters. No adverse effects were reported with vitamin C supplementation in either animal models or human participants; thus, oral vitamin C appears to be a safe supplement but lacks clinical evidence compared with controls. Because of the limited number of human studies, further clinical investigations are needed before the implementation of vitamin C as a postinjury supplement.
Collapse
Affiliation(s)
- Nicholas N DePhillipo
- The Steadman Clinic, Vail, Colorado, USA.,Steadman Philippon Research Institute, Vail, Colorado, USA
| | - Zachary S Aman
- Steadman Philippon Research Institute, Vail, Colorado, USA
| | | | - J P Begley
- The Steadman Clinic, Vail, Colorado, USA
| | - Gilbert Moatshe
- Steadman Philippon Research Institute, Vail, Colorado, USA.,Oslo University Hospital, Oslo, Norway.,OSTRC, Norwegian School of Sports Science, Oslo, Norway
| | - Robert F LaPrade
- The Steadman Clinic, Vail, Colorado, USA.,Steadman Philippon Research Institute, Vail, Colorado, USA
| |
Collapse
|
6
|
Differentiation of Promonocytic U937 Cells to Monocytes Is Associated with Reduced Mitochondrial Transport of Ascorbic Acid. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:4194502. [PMID: 29576847 PMCID: PMC5822789 DOI: 10.1155/2018/4194502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/30/2017] [Accepted: 12/26/2017] [Indexed: 12/20/2022]
Abstract
Growth of promonocytic U937 cells in the presence of DMSO promotes their differentiation to monocytes. After 4 days of culture in differentiating medium, these cells ceased to proliferate, displayed downregulated ryanodine receptor expression, and responded to specific stimuli with enhanced NADPH-oxidase-derived superoxide formation or cytosolic phospholipase A2-dependent arachidonic acid release. We found that the 4-day differentiation process is also associated with downregulated SVCT2 mRNA expression, in the absence of apparent changes in SVCT2 protein expression and transport rate of ascorbic acid (AA). Interestingly, under the same conditions, these cells accumulated lower amounts of the vitamin in their mitochondria, with an ensuing reduced response to external stimuli sensitive to the mitochondrial fraction of AA. Further analyses demonstrated an unexpected increase in mitochondrial SVCT2 protein expression, however, associated with reduced SVCT2-dependent AA uptake in isolated mitochondria. A decrease in the transporter Vmax, with no change in affinity, was found to account for this response. Differentiation of promonocytic cells to monocytes is therefore characterized by decreased SVCT2 mRNA expression that, even prior to the onset of SVCT2 protein downregulation or apparent changes in plasma membrane transport activity, impacts on the mitochondrial accumulation of the vitamin through a decreased Vmax of the transporter.
Collapse
|
7
|
Tavangar B, Arasteh S, Edalatkhah H, Salimi A, Doostmohammadi A, Seyedjafari E. Hardystonite-Coated Poly(l-lactide) Nanofibrous Scaffold and Efficient Osteogenic Differentiation of Adipose-Derived Mesenchymal Stem Cells. Artif Organs 2017; 42:E335-E348. [PMID: 28653337 DOI: 10.1111/aor.12891] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 09/16/2016] [Accepted: 10/26/2016] [Indexed: 01/07/2023]
Abstract
In this study, a ceramic-coated nanofibrous scaffold has been fabricated to biomimic the microstructure of natural extracellular matrix and the stiffening inorganic compartment of bone. Poly-l-lactic acid (PLLA) nanofibers were electrospun and exposed to oxygen plasma to induce hydrophilicity and promote ceramic adsorption. Hardystonite (HS), which possesses superior osteoinduction potential over hydroxyapatite, was coated on plasma-treated PLLA nanofibers by drenching the nanofibers in HS suspension. Pure and composite PLLA-based scaffolds were characterized in terms of physical and biological properties. In vitro cultivation of adipose-derived mesenchymal stem cells (AMSCs) on the scaffolds displayed that the composite scaffold is able to further support cell attachment and proliferation. In case of osteogenic differentiation of AMSCs, HS coating significantly increased the synthesis and activity of alkaline phosphate over 21 days period. In addition, the composite scaffold showed improved mineralization. The expression level of osteonectin and osteocalcin genes was significantly enhanced by HS coating of nanofibers. The biological improvement of PLLA nanofibrous matrix in the presence of HS nanoparticles could either be attributed to the release and stimulatory effect of constituent ions of HS or to the modification of chemico-physical properties of the resultant ceramic by silicon and zinc present in HS.
Collapse
Affiliation(s)
- Banafsheh Tavangar
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
| | - Shaghayegh Arasteh
- Reproductive Biotechnology Research Center, Avicenna Research Institute, Tehran, Iran
| | - Haleh Edalatkhah
- Reproductive Biotechnology Research Center, Avicenna Research Institute, Tehran, Iran
| | - Ali Salimi
- Nanobiotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ali Doostmohammadi
- Materials Department, Engineering Faculty, Shahrekord University, Shahrekord, Iran
| | - Ehsan Seyedjafari
- Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran
| |
Collapse
|
8
|
SVCT2 Overexpression in Neuroblastoma Cells Induces Cellular Branching that is Associated with ERK Signaling. Mol Neurobiol 2015; 53:6668-6679. [DOI: 10.1007/s12035-015-9553-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 11/18/2015] [Indexed: 12/21/2022]
|
9
|
Muñoz A, Villagrán M, Guzmán P, Solíz C, Gatica M, Aylwin C, Sweet K, Maldonado M, Escobar E, Reyes AM, Toledo JR, Sánchez O, Oñate SA, Carlos Vera J, Rivas CI. Cis-regulatory elements involved in species-specific transcriptional regulation of the SVCT1 gene in rat and human hepatoma cells. Free Radic Biol Med 2015; 85:183-96. [PMID: 25933589 DOI: 10.1016/j.freeradbiomed.2015.04.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/09/2015] [Accepted: 04/20/2015] [Indexed: 01/06/2023]
Abstract
Ascorbic acid is transported into cells by the sodium-coupled vitamin C transporters (SVCTs). Recently, we obtained evidence of differential regulation of SVCT expression in response to acute oxidative stress in cells from species that differ in their capacity to synthesize vitamin C, with a marked decrease in SVCT1 mRNA and protein levels in rat hepatoma cells that was not observed in human hepatoma cells. To better understand the regulatory aspects involved, we performed a structural and functional analysis of the proximal promoter of the SVCT1 rat gene. We cloned a 1476-bp segment containing the proximal promoter of the rat SVCT1 gene and generated deletion-derived truncated promoters of decreasing sizes and mutant promoters by modification of consensus binding sites for transcription factors by site-directed mutagenesis. We next analyzed their capacity to direct the transcription of a reporter gene after transfection into rat H4IIE and human HepG2 hepatoma cells, in experiments involving the coexpression of transcription factors whose consensus binding sequences are present in the SVCT1 promoter. This analysis revealed the presence of two critical cis-regulatory elements of the transcriptional activity of the rat SVCT1 gene promoter, sites containing consensus sequences for the binding of the transcription factors Bach1 and HNF4 that are not present in equivalent locations in the human SVCT1 gene promoter. Moreover, a consensus site for HNF1 that is crucial for the regulation of the human SVCT1 promoter is present in the SVCT1 rat promoter but has no effect on its transcriptional activity. These findings imply that regulation of vitamin C metabolism in the rat, a species with the capacity to synthesize large amounts of ascorbic acid, may differ from that of humans, a species that must obtain ascorbic acid from the diet through a transport mechanism that depends on proper SVCT1 expression.
Collapse
Affiliation(s)
- Alejandra Muñoz
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Marcelo Villagrán
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Paula Guzmán
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Carlos Solíz
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Marcell Gatica
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Carlos Aylwin
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Karen Sweet
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Mafalda Maldonado
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Elizabeth Escobar
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Alejandro M Reyes
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, Valdivia, Chile
| | - Jorge R Toledo
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Oliberto Sánchez
- Departamento de Farmacología, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Sergio A Oñate
- Departamento de Especialidades Médicas, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile
| | - Juan Carlos Vera
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile.
| | - Coralia I Rivas
- Departamento de Fisiopatología, Facultad de Medicina, Universidad de Concepción, Concepción, Bio-Bio 4070386, Chile.
| |
Collapse
|
10
|
Patil S, Paul S. A comprehensive review on the role of various materials in the osteogenic differentiation of mesenchymal stem cells with a special focus on the association of heat shock proteins and nanoparticles. Cells Tissues Organs 2014; 199:81-102. [PMID: 25401759 DOI: 10.1159/000362226] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2014] [Indexed: 11/19/2022] Open
Abstract
Mesenchymal stem cells (MSCs) have important roles in the area of regenerative medicine and clinical applications due to their pluripotent nature. Osteogenic differentiation of MSCs has been studied extensively using various stimulants to develop models of bone repair. There are several factors that enhance the differentiation of MSCs into bone tissues. This review focuses on the effects of various inducers on the osteoblast differentiation of MSCs at different stages of cellular development. We discuss the various growth factors, hormones, vitamins, cytokines, chemical stimulants, and mechanical forces applied in bioreactors that play an essential role in the proliferation, differentiation, and matrix mineralization of stem cells during osteogenesis. Various nanoparticles have also been used recently for the same purpose and the results are promising. Moreover, we review the role of various stresses, including thermal stress, and the subsequent involvement of heat shock proteins as inducers of the proliferation and differentiation of osteoblasts. We also report how various proteasome inhibitors have been shown to induce proliferation and osteogenic differentiation of MSCs in a number of cases. In this communication, the role of peptide-based scaffolds in osteoblast proliferation and differentiation is also reviewed. Based on the reviewed information, this article proposes novel possibilities for the enhancement of proliferation, differentiation, and migration of osteoblasts from MSCs. © 2014 S. Karger AG, Basel.
Collapse
Affiliation(s)
- Supriya Patil
- Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela, India
| | | |
Collapse
|
11
|
Giuliani C, Peri A. Effects of Hyponatremia on the Brain. J Clin Med 2014; 3:1163-77. [PMID: 26237597 PMCID: PMC4470176 DOI: 10.3390/jcm3041163] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/18/2014] [Accepted: 10/10/2014] [Indexed: 12/31/2022] Open
Abstract
Hyponatremia is a very common electrolyte disorder, especially in the elderly, and is associated with significant morbidity, mortality and disability. In particular, the consequences of acute hyponatremia on the brain may be severe, including permanent disability and death. Also chronic hyponatremia can affect the health status, causing attention deficit, gait instability, increased risk of falls and fractures, and osteoporosis. Furthermore, an overly rapid correction of hyponatremia can be associated with irreversible brain damage, which may be the result of the osmotic demyelination syndrome. This review analyzes the detrimental consequences of acute and chronic hyponatremia and its inappropriate correction on the brain and the underlying physiopathological mechanisms, with a particular attention to the less known in vivo and in vitro effects of chronic hyponatremia.
Collapse
Affiliation(s)
- Corinna Giuliani
- Endocrine Unit, Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence 50139, Italy.
| | - Alessandro Peri
- Endocrine Unit, Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence 50139, Italy.
| |
Collapse
|
12
|
The Level of Orally Ingested Vitamin C Affected the Expression of Vitamin C Transporters and Vitamin C Accumulation in the Livers of ODS Rats. Biosci Biotechnol Biochem 2014; 75:2394-7. [DOI: 10.1271/bbb.110312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
13
|
Jaiswal AK, Chhabra H, Kadam SS, Londhe K, Soni VP, Bellare JR. Hardystonite improves biocompatibility and strength of electrospun polycaprolactone nanofibers over hydroxyapatite: A comparative study. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2013; 33:2926-36. [DOI: 10.1016/j.msec.2013.03.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/19/2013] [Accepted: 03/12/2013] [Indexed: 01/08/2023]
|
14
|
Zinc supplementation inhibits the increase in osteoclastogenesis and decrease in osteoblastogenesis in streptozotocin-induced diabetic rats. Eur J Pharmacol 2013; 714:41-7. [PMID: 23735664 DOI: 10.1016/j.ejphar.2013.05.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/03/2013] [Accepted: 05/20/2013] [Indexed: 01/16/2023]
Abstract
Zinc (Zn) has been shown to stimulate bone formation and inhibit osteoclastic bone resorption and osteoclastogenesis. However, the effects of Zn on bone metabolism in diabetic animals remain to be clarified in vivo. Here, the effects of Zn supplementation on bone metabolism, including osteoclastogenesis and osteoblastogenesis, were investigated using streptozotocine (STZ)-induced diabetic rats. Zn-supplemented water (7.5 mg/L) was given for 1 week to diabetic rats injected with STZ (30 mg/kg body weight) 1 week earlier. The Zn supplement prevented a decrease in the activity and mRNA of alkaline phosphatase (ALP), osteocalcin mRNA, and hydroxyproline and calcium levels, and an increase in the activity and mRNA of tartrate-resistant acid phosphatase (TRAP) and cathepsin K in the proximal tibia of diabetic rats. Histological analysis revealed that the Zn supplement inhibited the diabetes-induced increase and decrease in the number of osteoclasts and osteoblasts, respectively, in the metaphysis of the proximal tibia. The increase in mRNA levels of receptor for activation of NF-κB (RANK), c-fos, c-jun, TRAP, and cathepsin K and decrease in the expression of Runx2, Dlx5, osterix, ALP, osteocalcin, and collagen were prevented by the supplement. The decrease in β-catenin, phosphorylated GSK3β, phosphorylated Akt, insulin-like growth factor 1 (IGF-1), and IGF-1 receptor (IGF-1R) protein levels in diabetic rats was also inhibited, although Zn did not affect the diabetes-increased gene and protein expression of Sost and Dkk1. These results suggested that Zn prevented the diabetes-induced increase in osteoclastogenesis and decrease in osteoblastogenesis by inhibiting RANK expression and stimulating IGF-1/IGF-1R/Akt/GSK3β/β-catenin signaling, respectively.
Collapse
|
15
|
Mavropoulos E, Hausen M, Costa AM, Alves G, Mello A, Ospina CA, Mir M, Granjeiro JM, Rossi AM. The impact of the RGD peptide on osteoblast adhesion and spreading on zinc-substituted hydroxyapatite surface. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2013; 24:1271-1283. [PMID: 23494616 DOI: 10.1007/s10856-013-4851-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/16/2013] [Indexed: 06/01/2023]
Abstract
The incorporation of zinc into the hydroxyapatite structure (ZnHA) has been proposed to stimulate osteoblast proliferation and differentiation. Another approach to improve cell adhesion and hydroxyapatite (HA) performance is coating HA with adhesive proteins or peptides such as RGD (arginine-glycine-aspartic acid). The present study investigated the adhesion of murine osteoblastic cells to non-sintered zinc-substituted HA disks before and after the adsorption of RGD. The incorporation of zinc into the HA structure simultaneously changed the topography of disk's surface on the nanoscale and the disk's surface chemistry. Fluorescence microscopy analyses using RGD conjugated to a fluorescein derivative demonstrated that ZnHA adsorbed higher amounts of RGD than non-substituted HA. Zinc incorporation into HA promoted cell adhesion and spreading, but no differences in the cell density, adhesion and spreading were detected when RGD was adsorbed onto ZnHA. The pre-treatment of disks with fetal bovine serum (FBS) greatly increased the cell density and cell surface area for all RGD-free groups, overcoming the positive contribution of zinc to cell adhesion. The presence of RGD on the ZnHA surface impaired the effects of FBS pre-treatment possibly due to competition between FBS proteins and RGD for surface binding sites.
Collapse
Affiliation(s)
- Elena Mavropoulos
- Brazilian Center for Physics Research, Xavier Sigaud 150, Urca, RJ 22290-180, Brazil.
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Chothe PP, Chutkan N, Sangani R, Wenger KH, Prasad PD, Thangaraju M, Hamrick MW, Isales CM, Ganapathy V, Fulzele S. Sodium-coupled vitamin C transporter (SVCT2): expression, function, and regulation in intervertebral disc cells. Spine J 2013; 13:549-57. [PMID: 23415019 DOI: 10.1016/j.spinee.2013.01.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 11/16/2012] [Accepted: 01/13/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Vitamin C (ascorbic acid [AA]) is essential for the synthesis of collagen and also acts as an antioxidant in the intervertebral disc (IVD). However, there is very little information currently available on the identity of the transporter that facilitates AA entry into IVD cells and the factors that mediate the transport process. PURPOSE To investigate the expression of the two known isoforms of Na+ -coupled vitamin C transporter, SVCT1 and SVCT2, in IVD cells and its regulation by insulin-like growth factor 1 (IGF-1) and the steroid hormone dexamethasone. STUDY DESIGN To identify the expression and functional activity of the sodium-dependent vitamin C transporter (SVCT) in the IVD. METHODS Uptake studies were carried out with rabbit annulus fibrosis and nucleus pulposus cells in 24-well plates using [14C]-AA. To characterize SVCT transporter, uptake was done in the presence and absence of Na+ in the uptake buffer. Time dependency, Na+ activation kinetics, saturation kinetics, and substrate selectivity studies were performed. Regulatory studies were performed in the presence of IGF-1 and the steroid hormone dexamethasone. Gene expression was analyzed by quantitative polymerase chain reaction. RESULTS Our real-time polymerase chain reaction results showed the presence of SVCT2 but not SVCT1 in IVD cells. Uptake of vitamin C in IVD cells is Na+ dependent and saturable. The Michaelis constant for the process is 96±11 μM. The activation of vitamin C uptake by Na+ exhibits a sigmoidal relationship, indicating involvement of more than one Na+ in the activation process. The uptake system does not recognize any other water-soluble vitamin as a substrate. Immunocytochemical analysis shows robust expression of SVCT2 protein in IVD cells. The growth factors IGF-1 and the steroid hormone dexamethasone upregulate the expression of SVCT2 in IVD cells. CONCLUSIONS Our studies demonstrate that the active SVCT2 is expressed in IVD cells and that the expression of this transporter is regulated by growth factors IGF-1 and dexamethasone.
Collapse
Affiliation(s)
- Paresh P Chothe
- Department of Biochemistry and Molecular Biology, Georgia Health Science University, 1459 Laney Walker Blvd, Augusta, GA 30912, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Barsony J, Manigrasso MB, Xu Q, Tam H, Verbalis JG. Chronic hyponatremia exacerbates multiple manifestations of senescence in male rats. AGE (DORDRECHT, NETHERLANDS) 2013; 35:271-88. [PMID: 22218780 PMCID: PMC3592950 DOI: 10.1007/s11357-011-9347-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 11/23/2011] [Indexed: 05/27/2023]
Abstract
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is frequently responsible for chronic hyponatremia in the elderly due to age-related disruption of the inhibitory component of brain osmoregulatory mechanisms. Recent research has indicated that chronic hyponatremia is associated with gait disturbances, increased falls, and bone fragility in humans, and we have found that chronic hyponatremia causes increased bone resorption and reduced bone mineral density in young rats. In this study, we used a model of SIADH to study multi-organ consequences of chronic hyponatremia in aged rats. Sustained hyponatremia for 18 weeks caused progressive reduction of bone mineral density by DXA and decreased bone ash calcium, phosphate and sodium contents at the tibia and lumbar vertebrae. Administration of 10-fold higher vitamin D during the last 8 weeks of the study compensated for the reduction in bone formation and halted bone loss. Hyponatremic rats developed hypogonadism, as indicated by slightly lower serum testosterone and higher serum FSH and LH concentrations, markedly decreased testicular weight, and abnormal testicular histology. Aged hyponatremic rats also manifested decreased body fat, skeletal muscle sarcopenia by densitometry, and cardiomyopathy manifested as increased heart weight and perivascular and interstitial fibrosis by histology. These findings are consistent with recent results in cultured osteoclastic cells, indicating that low extracellular sodium concentrations increased oxidative stress, thereby potentially exacerbating multiple manifestations of senescence. Future prospective studies in patients with SIADH may indicate whether these multi-organ age-related comorbidities may potentially contribute to the observed increased incidence of fractures and mortality in this population.
Collapse
Affiliation(s)
- Julia Barsony
- Division of Endocrinology and Metabolism, Georgetown University, Washington, DC 20007 USA
| | - Michaele B. Manigrasso
- Division of Endocrinology and Metabolism, Georgetown University, Washington, DC 20007 USA
| | - Qin Xu
- Division of Endocrinology and Metabolism, Georgetown University, Washington, DC 20007 USA
| | - Helen Tam
- Division of Endocrinology and Metabolism, Georgetown University, Washington, DC 20007 USA
| | - Joseph G. Verbalis
- Division of Endocrinology and Metabolism, Georgetown University, Washington, DC 20007 USA
| |
Collapse
|
18
|
Liu Y, Lim J, Teoh SH. Review: development of clinically relevant scaffolds for vascularised bone tissue engineering. Biotechnol Adv 2012; 31:688-705. [PMID: 23142624 DOI: 10.1016/j.biotechadv.2012.10.003] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 10/21/2012] [Accepted: 10/26/2012] [Indexed: 12/15/2022]
Abstract
Clinical translation of scaffold-based bone tissue engineering (BTE) therapy still faces many challenges despite intense investigations and advancement over the years. To address these clinical barriers, it is important to analyse the current technical challenges in constructing a clinically relevant scaffold and subsequent clinical issues relating to bone repair. This review highlights the key challenges hampering widespread clinical translation of scaffold-based vascularised BTE, with a focus on the repair of large non-union defects. The main limitations of current scaffolds include the lack of sufficient vascularisation, insufficient mechanical strength as well as issues relating to the osseointegration of the bioresorbable scaffold and bone infection management. Critical insights on the current trends of scaffold technologies and future directions for advancing next-generation BTE scaffolds into the clinical realm are discussed. Considerations concerning regulatory approval and the route towards commercialisation of the scaffolds for widespread clinical utility will also be introduced.
Collapse
Affiliation(s)
- Yuchun Liu
- Division of Bioengineering, School of Chemical and Biomedical Engineering, 70 Nanyang Drive, Nanyang Technological University, Singapore 637459, Singapore
| | | | | |
Collapse
|
19
|
Chen L, Zhu H, Pan Y, Tang C, Watanabe M, Ruan H, Wang Y, Wang J, Yao HY, Iguchi T, Wu X. Ascorbic acid uptaken by sodium-dependent vitamin C transporter 2 induces βhCG expression through Sp1 and TFAP2A transcription factors in human choriocarcinoma cells. J Clin Endocrinol Metab 2012; 97:E1667-76. [PMID: 22745243 DOI: 10.1210/jc.2012-1753] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Vitamin C [ascorbic acid (AA)] is transported by sodium-dependent vitamin C transporters (SVCT) 1 and 2, and our previous studies show AA induces a dramatic production of steroid hormones in human choriocarcinoma cells. However, whether AA induces the production of placental polypeptide hormones remains unknown. Here we investigated the mechanisms governing AA-induced β-human chorionic gonadotropin (hCG) expression. METHODS Frozen sections from human term placentas were used for immunostaining of SVCT, and βhCG mRNA expression and its production in primary human placental cytotrophoblasts and JEG-3 cells were examined by quantitative RT-PCR and ELISA, respectively. Knockdown of SVCT2, transcription factor activating enhancer-binding protein 2α (TFAP2A), or specificity protein-1 (Sp1) expression was achieved by retrovirus-mediated short hairpin RNA, and the transcriptional factors responsible for AA-induced βhCG expression was identified by reporter constructs. RESULTS Both SVCT1 and SVCT2 are expressed in human term placentas. SVCT2 is predominantly localized in the syncytial layer, whereas SVCT1 is predominantly distributed in the villous core. AA dramatically induces βhCG mRNA expression and its production in JEG-3 cells and primary human cytotrophoblasts, and knockdown of SVCT2 expression in JEG-3 cells significantly decreases AA-induced βhCG expression. Data from βhCG5 construct and its deletion mutants further indicate that AA induces βhCG5 transactivation through Sp1 and TFAP2A transcriptional factors, and silence of Sp1 and/or TFAP2A expression significantly decreased AA-induced βhCG5 reporter activity and βhCG expression as well. CONCLUSIONS The present study revealed the novel effects of AA on polypeptide hormone, βhCG, production and the potential mechanisms governing AA-induced βhCG expression, suggesting the potentially indispensable roles of AA in placental endocrine and pregnant maintenance.
Collapse
Affiliation(s)
- Lihua Chen
- Department of Pharmacology, School of Medicine, Zhejiang University, No. 866, Yuhangtang Road, Hangzhou 310058, People's Republic of China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Fulzele S, Chothe P, Sangani R, Chutkan N, Hamrick M, Bhattacharyya M, Prasad PD, Zakhary I, Bowser M, Isales C, Ganapathy V. Sodium-dependent vitamin C transporter SVCT2: expression and function in bone marrow stromal cells and in osteogenesis. Stem Cell Res 2012; 10:36-47. [PMID: 23089627 DOI: 10.1016/j.scr.2012.08.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 08/13/2012] [Accepted: 08/14/2012] [Indexed: 01/07/2023] Open
Abstract
Ascorbic acid (Vitamin C) has a critical role in bone formation and osteoblast differentiation, but very little is known about the molecular mechanisms of ascorbic acid entry into bone marrow stromal cells (BMSCs). To address this gap in knowledge, we investigated the identity of the transport system that is responsible for the uptake of ascorbic acid into bone marrow stromal cells (BMSCs). First, we examined the expression of the two known isoforms of the sodium-coupled ascorbic acid transporter, namely SVCT1 and SVCT2, in BMSCs (Lin-ve Sca1+ve) and bone at the mRNA level. Only SVCT2 mRNA was detected in BMSCs and bone. Uptake of ascorbic acid in BMSCs was Na(+)-dependent and saturable. In order to define the role of SVCT2 in BMSC differentiation into osteoblasts, BMSCs were stimulated with osteogenic media for different time intervals, and the activity of SVCT2 was monitored by ascorbic acid uptake. SVCT2 expression was up-regulated during the osteogenic differentiation of BMSCs; the expression was maximal at the earliest phase of differentiation. Subsequently, osteogenesis was inhibited in BMSCs upon knock-down of SVCT2 by lentivirus shRNA. We also found that the expression of the SVCT2 could be negatively or positively modulated by the presence of oxidant (Sin-1) or antioxidant (Ascorbic acid) compounds, respectively, in BMSCs. Furthermore, we found that this transporter is also regulated with age in mouse bone. These data show that SVCT2 plays a vital role in the osteogenic differentiation of BMSCs and that its expression is altered under conditions associated with redox reaction. Our findings could be relevant to bone tissue engineering and bone related diseases such as osteoporosis in which oxidative stress and aging plays important role.
Collapse
Affiliation(s)
- Sadanand Fulzele
- Department of Orthopaedic Surgery, Georgia health Science University, Augusta, GA 30912, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Mardones L, Zúñiga FA, Villagrán M, Sotomayor K, Mendoza P, Escobar D, González M, Ormazabal V, Maldonado M, Oñate G, Angulo C, Concha II, Reyes AM, Cárcamo JG, Barra V, Vera JC, Rivas CI. Essential role of intracellular glutathione in controlling ascorbic acid transporter expression and function in rat hepatocytes and hepatoma cells. Free Radic Biol Med 2012; 52:1874-87. [PMID: 22348976 DOI: 10.1016/j.freeradbiomed.2012.02.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 02/07/2012] [Accepted: 02/09/2012] [Indexed: 01/21/2023]
Abstract
Although there is in vivo evidence suggesting a role for glutathione in the metabolism and tissue distribution of vitamin C, no connection with the vitamin C transport systems has been reported. We show here that disruption of glutathione metabolism with buthionine-(S,R)-sulfoximine (BSO) produced a sustained blockade of ascorbic acid transport in rat hepatocytes and rat hepatoma cells. Rat hepatocytes expressed the Na(+)-coupled ascorbic acid transporter-1 (SVCT1), while hepatoma cells expressed the transporters SVCT1 and SVCT2. BSO-treated rat hepatoma cells showed a two order of magnitude decrease in SVCT1 and SVCT2 mRNA levels, undetectable SVCT1 and SVCT2 protein expression, and lacked the capacity to transport ascorbic acid, effects that were fully reversible on glutathione repletion. Interestingly, although SVCT1 mRNA levels remained unchanged in rat hepatocytes made glutathione deficient by in vivo BSO treatment, SVCT1 protein was absent from the plasma membrane and the cells lacked the capacity to transport ascorbic acid. The specificity of the BSO treatment was indicated by the finding that transport of oxidized vitamin C (dehydroascorbic acid) and glucose transporter expression were unaffected by BSO treatment. Moreover, glutathione depletion failed to affect ascorbic acid transport, and SVCT1 and SVCT2 expression in human hepatoma cells. Therefore, our data indicate an essential role for glutathione in controlling vitamin C metabolism in rat hepatocytes and rat hepatoma cells, two cell types capable of synthesizing ascorbic acid, by regulating the expression and subcellular localization of the transporters involved in the acquisition of ascorbic acid from extracellular sources, an effect not observed in human cells incapable of synthesizing ascorbic acid.
Collapse
Affiliation(s)
- Lorena Mardones
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160C, Concepción, Chile
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Qiao H, May JM. Interaction of the transcription start site core region and transcription factor YY1 determine ascorbate transporter SVCT2 exon 1a promoter activity. PLoS One 2012; 7:e35746. [PMID: 22532872 PMCID: PMC3332055 DOI: 10.1371/journal.pone.0035746] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 03/23/2012] [Indexed: 01/10/2023] Open
Abstract
Transcription of the ascorbate transporter, SVCT2, is driven by two distinct promoters in exon 1 of the transporter sequence. The exon 1a promoter lacks a classical transcription start site and little is known about regulation of promoter activity in the transcription start site core (TSSC) region. Here we present evidence that the TSSC binds the multifunctional initiator-binding protein YY1. Electrophoresis shift assays using YY1 antibody showed that YY1 is present as one of two major complexes that specifically bind to the TSSC. The other complex contains the transcription factor NF-Y. Mutations in the TSSC that decreased YY1 binding also impaired the exon 1a promoter activity despite the presence of an upstream activating NF-Y/USF complex, suggesting that YY1 is involved in the regulation of the exon 1a transcription. Furthermore, YY1 interaction with NF-Y and/or USF synergistically enhanced the exon 1a promoter activity in transient transfections and co-activator p300 enhanced their synergistic activation. We propose that the TSSC plays a vital role in the exon 1a transcription and that this function is partially carried out by the transcription factor YY1. Moreover, co-activator p300 might be able to synergistically enhance the TSSC function via a “bridge” mechanism with upstream sequences.
Collapse
Affiliation(s)
- Huan Qiao
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
| | | |
Collapse
|
23
|
May JM. The SLC23 family of ascorbate transporters: ensuring that you get and keep your daily dose of vitamin C. Br J Pharmacol 2012; 164:1793-801. [PMID: 21418192 DOI: 10.1111/j.1476-5381.2011.01350.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The ascorbate transporters SVCT1 and SVCT2 are crucial for maintaining intracellular ascorbate concentrations in most cell types. Although the two transporter isoforms are highly homologous, they have different physiologic functions. The SVCT1 is located primarily in epithelial cells and has its greatest effect in reabsorbing ascorbate in the renal tubules. The SVCT2 is located in most non-epithelial tissues, with the highest expression in brain and neuroendocrine tissues. These transporters are hydrophobic membrane proteins that have a high affinity and are highly selective for ascorbate. Their ability to concentrate ascorbate inside cells is driven by the sodium gradient across the plasma membrane as generated by Na+/K+ ATPase. They can concentrate ascorbate 20 to 60-fold over plasma ascorbate concentrations. Ascorbate transport on these proteins is regulated at the transcriptional, translational and post-translational levels. Available studies show that transporter function is acutely regulated by protein kinases A and C, whereas transporter expression is increased by low intracellular ascorbate and associated oxidative stress. The knockout of the SVCT2 in mice is lethal on day 1 of life, and almost half of SVCT1 knockout mice do not survive to weaning. These findings confirm the importance both of cellular ascorbate and of the two transport proteins as key to maintaining intracellular ascorbate. LINKED ARTICLES This article is part of a themed section on Transporters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2011.164.issue-7.
Collapse
Affiliation(s)
- James M May
- Departments of Medicine and Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0475, USA.
| |
Collapse
|
24
|
CpG methylation at the USF-binding site mediates cell-specific transcription of human ascorbate transporter SVCT2 exon 1a. Biochem J 2011; 440:73-84. [PMID: 21770893 DOI: 10.1042/bj20110392] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SVCT2 (sodium-vitamin C co-transporter 2) is the major transporter mediating vitamin C uptake in most organs. Its expression is driven by two promoters (CpG-poor exon 1a promoter and CpG-rich exon 1b promoter). In the present study, we mapped discrete elements within the proximal CpG-poor promoter responsible for exon 1a transcription. We identified two E boxes for USF (upstream stimulating factor) binding and one Y box for NF-Y (nuclear factor Y) binding. We show further that NF-Y and USF bind to the exon 1a promoter in a co-operative manner, amplifying the binding of each to the promoter, and is absolutely required for the full activity of the exon 1a promoter. The analysis of the CpG site located at the upstream USF-binding site in the promoter showed a strong correlation between expression and demethylation. It was also shown that exon 1a transcription was induced in cell culture treated with the demethylating agent decitabine. The specific methylation of this CpG site impaired both the binding of USF and the formation of the functional NF-Y-USF complex as well as promoter activity, suggesting its importance for cell-specific transcription. Thus CpG methylation at the upstream USF-binding site functions in establishing and maintaining cell-specific transcription from the CpG-poor SVCT2 exon 1a promoter.
Collapse
|
25
|
Mouriño V, Cattalini JP, Boccaccini AR. Metallic ions as therapeutic agents in tissue engineering scaffolds: an overview of their biological applications and strategies for new developments. J R Soc Interface 2011; 9:401-19. [PMID: 22158843 PMCID: PMC3262432 DOI: 10.1098/rsif.2011.0611] [Citation(s) in RCA: 219] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This article provides an overview on the application of metallic ions in the fields of regenerative medicine and tissue engineering, focusing on their therapeutic applications and the need to design strategies for controlling the release of loaded ions from biomaterial scaffolds. A detailed summary of relevant metallic ions with potential use in tissue engineering approaches is presented. Remaining challenges in the field and directions for future research efforts with focus on the key variables needed to be taken into account when considering the controlled release of metallic ions in tissue engineering therapeutics are also highlighted.
Collapse
Affiliation(s)
- Viviana Mouriño
- Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry, University of Buenos Aires, 956 Junín Street, Sixth Floor, Buenos Aires CP1113, Argentina
| | | | | |
Collapse
|
26
|
Takino Y, Okura F, Kitazawa M, Iwasaki K, Tagami H. Zinc l-pyrrolidone carboxylate inhibits the UVA-induced production of matrix metalloproteinase-1 by in vitro cultured skin fibroblasts, whereas it enhances their collagen synthesis. Int J Cosmet Sci 2011; 34:23-8. [DOI: 10.1111/j.1468-2494.2011.00676.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
27
|
Hie M, Tsukamoto I. Administration of zinc inhibits osteoclastogenesis through the suppression of RANK expression in bone. Eur J Pharmacol 2011; 668:140-6. [PMID: 21806983 DOI: 10.1016/j.ejphar.2011.07.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 06/20/2011] [Accepted: 07/14/2011] [Indexed: 01/08/2023]
Abstract
Zinc (Zn) has been known to inhibit osteoclastic bone resorption and stimulate osteoblastic bone formation. However, the mechanisms responsible for these effects have not been well characterized in vivo. Here, the effects of a dietary administration of Zn on osteoclastogenesis and osteoblastogenesis were investigated in Zn-adequate rats. The administration of Zn decreased the activities of bone tartrate-resistant acid phosphatase (TRAP) and cathepsin K, without affecting the serum osteocalcin level. Histological analysis showed a decrease in the number of osteoclasts with a normal number of osteoblasts in the metaphysis of the proximal tibia. The mRNA levels of receptor for activation of NF-κB (RANK), c-fos, c-jun, TRAP and cathepsin K were significantly decreased, although those of RANK ligand, macrophage colony-stimulating factor and c-fms were unaltered. The gene expression of bone morphogenic protein-2, Runx2, Dlx5, osterix, alkaline phosphatase, osteocalcin and collagen was not affected. The level of the RANK protein decreased, while the levels of the Runx2 and β-catenin proteins were unchanged. Further, the osteoclastic differentiation of precursor cells in vitro was suppressed. The suppressed osteoclastogenesis was associated with decreased levels of reactive oxygen species, extracellular signal-regulated kinase (ERK) activation and RANK expression. A lower lipid peroxide level and a higher glutathione level were also observed. These results suggested that Zn-administration did not affect osteoblastogenesis but decreased osteoclastogenesis by inhibiting RANK expression through suppression of the production of reactive oxygen species and ERK activation in Zn-adequate rats.
Collapse
Affiliation(s)
- Mamiko Hie
- Department of Food Science and Nutrition, Nara Women's University, Nara 630-8506, Japan
| | | |
Collapse
|
28
|
Alcantara EH, Lomeda RAR, Feldmann J, Nixon GF, Beattie JH, Kwun IS. Zinc deprivation inhibits extracellular matrix calcification through decreased synthesis of matrix proteins in osteoblasts. Mol Nutr Food Res 2011; 55:1552-60. [PMID: 21656670 DOI: 10.1002/mnfr.201000659] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Revised: 03/15/2011] [Accepted: 03/21/2011] [Indexed: 01/25/2023]
Abstract
SCOPE Zinc is implicated as an activator for bone formation, however, its influence on bone calcification has not been reported. This study examined how zinc regulates the bone matrix calcification in osteoblasts. METHODS AND RESULTS Two osteoblastic MC3T3-E1 cell subclones (SC 4 and SC 24 as high and low osteogenic differentiation, respectively) were cultured in normal osteogenic (OSM), Zinc deficient (Zn-, 1 μM), or adequate (Zn+, 15 μM) media up to 20 days. Cells (SC 4) were also supplemented with (50 μg/mL) or no ascorbic acid (AA) in combination with Zinc treatment. Zn- decreased collagen synthesis and matrix accumulation. Although AA is essential for collagen formation, its supplementation could not compensate for Zinc deficiency-induced detrimental effects on extracellular matrix mineralization. Zn- also decreased the medium and cell layer alkaline phosphatase ALP activity. This decreased ALP activity might cause the decrease of Pi accumulation in response to Zn-, as measured by von Kossa staining. Ca deposition in cell layers, measured by Alizarin red S staining, was also decreased by Zn(-) . CONCLUSION Our findings suggest that zinc deprivation inhibits extracellular matrix calcification in osteoblasts by decreasing the synthesis and activity of matrix proteins, type I collagen and ALP, and decreasing Ca and Pi accumulation. Therefore zinc deficiency can be considered as risk factor for poor extracellular matrix calcification.
Collapse
Affiliation(s)
- Ethel H Alcantara
- Department of Food Science and Nutrition, Andong National University, 388 Songchundong,Andong, Kyungbook, South Korea
| | | | | | | | | | | |
Collapse
|
29
|
Sandukji A, Al-Sawaf H, Mohamadin A, Alrashidi Y, Sheweita SA. Oxidative stress and bone markers in plasma of patients with long-bone fixative surgery: role of antioxidants. Hum Exp Toxicol 2011; 30:435-442. [PMID: 20534639 DOI: 10.1177/0960327110374203] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2023]
Abstract
It is well known that bone markers (e.g. osteocalcin and alkaline phosphatase) play a significant role in healing of bone fractures, whereas oxidative stress delay such healing. The present study aimed to investigate the effect of a mixture of antioxidants (vitamins A, C, E, and selenium) on oxidative stress parameters, and the levels of bone healing markers in the plasma of male patients following fixative surgery of long bones. Antioxidant tablets (300 µg vitamin A, 10 mg vitamin E, 60 mg vitamin C, and 75 µg selenium) were administered to groups 3 and 4 (10 patients in each) for 1 and 2 weeks, respectively, in addition to the regular postoperative treatment. Groups 1 (25 patients) and 2 (10 patients) received the regular post-operative treatment consisting of intravenous (I.V.) second generation of cephalosporin 1000 mg/day for 3 days, oral diclofenac 50 mg, and paracetamol 500 mg twice daily for 15 days. Osteocalcin level and alkaline phosphatase activity as well as antioxidant enzymes superoxide dismutase (SOD), glutathione reductase (GR), as well as glutathione (GSH), and thiobarbituric acid reactive substances (TBARS) as indices of oxidative stress, were determined in the plasma of all patients after 1 or 2 weeks of long-bone fixative surgery. The results revealed that osteocalcin level and the activity of alkaline phosphatase were markedly increased in the plasma of patients who received antioxidants for 2 weeks. In addition, after 1 and/or 2 weeks, the levels of TBARS were significantly lower in the antioxidant-treated patients compared with those who did not receive antioxidants. On the other hand, the activities of SOD and GR were markedly elevated in plasma of patients who received antioxidants after 1 or 2 weeks compared with patients who received regular therapy. Moreover, the level of plasma GSH was markedly increased only after 2 weeks in patients who received antioxidants. It is concluded that administration of antioxidant vitamins A, E, and C in addition to selenium could accelerate bone healing after long-bone fixative surgery. Therefore, antioxidants should be considered in designing therapeutic protocols in post-operative bone surgery.
Collapse
Affiliation(s)
- A Sandukji
- Department of Orthopedic Surgery, Taibah University, KSA
| | | | | | | | | |
Collapse
|
30
|
May JM. The SLC23 family of ascorbate transporters: ensuring that you get and keep your daily dose of vitamin C. Br J Pharmacol 2011. [PMID: 21418192 DOI: 10.1111/bph.2011.164.issue-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The ascorbate transporters SVCT1 and SVCT2 are crucial for maintaining intracellular ascorbate concentrations in most cell types. Although the two transporter isoforms are highly homologous, they have different physiologic functions. The SVCT1 is located primarily in epithelial cells and has its greatest effect in reabsorbing ascorbate in the renal tubules. The SVCT2 is located in most non-epithelial tissues, with the highest expression in brain and neuroendocrine tissues. These transporters are hydrophobic membrane proteins that have a high affinity and are highly selective for ascorbate. Their ability to concentrate ascorbate inside cells is driven by the sodium gradient across the plasma membrane as generated by Na+/K+ ATPase. They can concentrate ascorbate 20 to 60-fold over plasma ascorbate concentrations. Ascorbate transport on these proteins is regulated at the transcriptional, translational and post-translational levels. Available studies show that transporter function is acutely regulated by protein kinases A and C, whereas transporter expression is increased by low intracellular ascorbate and associated oxidative stress. The knockout of the SVCT2 in mice is lethal on day 1 of life, and almost half of SVCT1 knockout mice do not survive to weaning. These findings confirm the importance both of cellular ascorbate and of the two transport proteins as key to maintaining intracellular ascorbate. LINKED ARTICLES This article is part of a themed section on Transporters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2011.164.issue-7.
Collapse
Affiliation(s)
- James M May
- Departments of Medicine and Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232-0475, USA.
| |
Collapse
|
31
|
Ormazabal V, Zuñiga FA, Escobar E, Aylwin C, Salas-Burgos A, Godoy A, Reyes AM, Vera JC, Rivas CI. Histidine residues in the Na+-coupled ascorbic acid transporter-2 (SVCT2) are central regulators of SVCT2 function, modulating pH sensitivity, transporter kinetics, Na+ cooperativity, conformational stability, and subcellular localization. J Biol Chem 2010; 285:36471-85. [PMID: 20843809 DOI: 10.1074/jbc.m110.155630] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Na(+)-coupled ascorbic acid transporter-2 (SVCT2) activity is impaired at acid pH, but little is known about the molecular determinants that define the transporter pH sensitivity. SVCT2 contains six histidine residues in its primary sequence, three of which are exofacial in the transporter secondary structure model. We used site-directed mutagenesis and treatment with diethylpyrocarbonate to identify histidine residues responsible for SVCT2 pH sensitivity. We conclude that five histidine residues, His(109), His(203), His(206), His(269), and His(413), are central regulators of SVCT2 function, participating to different degrees in modulating pH sensitivity, transporter kinetics, Na(+) cooperativity, conformational stability, and subcellular localization. Our results are compatible with a model in which (i) a single exofacial histidine residue, His(413), localized in the exofacial loop IV that connects transmembrane helices VII-VIII defines the pH sensitivity of SVCT2 through a mechanism involving a marked attenuation of the activation by Na(+) and loss of Na(+) cooperativity, which leads to a decreased V(max) without altering the transport K(m); (ii) exofacial histidine residues His(203), His(206), and His(413) may be involved in maintaining a functional interaction between exofacial loops II and IV and influence the general folding of the transporter; (iii) histidines 203, 206, 269, and 413 affect the transporter kinetics by modulating the apparent transport K(m); and (iv) histidine 109, localized at the center of transmembrane helix I, might be fundamental for the interaction of SVCT2 with the transported substrate ascorbic acid. Thus, histidine residues are central regulators of SVCT2 function.
Collapse
Affiliation(s)
- Valeska Ormazabal
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario, Casilla 160C, Concepción, Chile
| | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Kwun IS, Cho YE, Lomeda RAR, Shin HI, Choi JY, Kang YH, Beattie JH. Zinc deficiency suppresses matrix mineralization and retards osteogenesis transiently with catch-up possibly through Runx 2 modulation. Bone 2010; 46:732-41. [PMID: 19913120 DOI: 10.1016/j.bone.2009.11.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2009] [Revised: 10/18/2009] [Accepted: 11/04/2009] [Indexed: 02/02/2023]
Abstract
A characteristic sign of zinc deficiency is retarded skeletal growth, but the role of zinc in osteoblasts is not well understood. Two major events for bone formation include osteoblast differentiation by bone marker gene expression, which is mainly regulated by bone-specific transcription factor Runx2 and extracellular matrix (ECM) mineralization by Ca deposits for bone nodule formation. We investigated whether zinc deficiency down-regulates bone marker gene transcription and whether this might occur through modulation of Runx2. We also investigated whether zinc deficiency decreases ECM mineralization in osteoblastic MC3T3-E1 cells. In the presence of 5 mumol/L TPEN as zinc chelator, zinc deficiency (ZnD: 1 micromol Zn/L) decreased bone marker gene (collagen type I, osteopontin, alkaline phosphatase, osteoclacin and parathyroid hormone receptor) expression, as compared to normal osteogenic medium (OSM) or zinc adequate medium (ZnA: 15 micromol/L) (P<0.05) both at 5 days (proliferation) and 15 days (matrix maturation). Decreased bone marker gene transcription by zinc deficiency could be caused by decreased nuclear Runx2 protein (P=0.05) and transcript (P<0.05) levels in ZnD. Furthermore, within the first 24 h of differentiation when Runx2 expression is induced, maximal Runx2 mRNA and nuclear protein levels were delayed in ZnD compared to OSM and ZnA. ECM Ca deposition was also lower in ZnD, which was also indirectly confirmed by detection of decreased cellular (synthesized) and medium (secreted) ALP activity as well as matrix ALP activity. Taken together, zinc deficiency attenuated osteogenic activity by decreasing bone marker gene transcription through reduced and delayed Runx2 expression and by decreasing ECM mineralization through inhibition of ALP activity in osteoblasts. Decreased and delayed bone marker gene, Runx2 expression and ECM mineralization in osteoblasts by zinc deficiency can be a potential explanation for the retarded skeletal growth which is the major zinc deficiency syndrome.
Collapse
Affiliation(s)
- In-Sook Kwun
- Department of Food Science and Nutrition, Andong National University, 388 Songchundong, Andong, Kyungpook 760-749, South Korea.
| | | | | | | | | | | | | |
Collapse
|
33
|
Michels AJ, Hagen TM. Hepatocyte nuclear factor 1 is essential for transcription of sodium-dependent vitamin C transporter protein 1. Am J Physiol Cell Physiol 2009; 297:C1220-7. [PMID: 19741195 DOI: 10.1152/ajpcell.00348.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transport and distribution of vitamin C is primarily regulated by the function of sodium-dependent vitamin C transporters (SVCTs). SVCT1 is expressed in the small intestine, liver, and kidney, organs that play a vital role in whole body vitamin C homeostasis. Despite the importance of this protein, little is known about regulation of the gene encoding SVCT1, Slc23a1. In this study, we present the first investigation of the transcriptional regulation of human Slc23a1, identifying transcription factors that may influence its expression. A 1,239-bp genomic DNA fragment corresponding to the 5'-flanking region of Slc23a1 was isolated from a human hepatocarcinoma cell line (HepG2) and sequenced. When cloned into a reporter gene construct, robust transcriptional activity was seen in this sequence, nearly 25-fold above the control vector. Deletion analysis of the SVCT1 reporter gene vector defined the minimal active promoter as a small 135-bp region upstream of the transcriptional start site. While several transcription factor binding sites were identified within this sequence, reporter constructs showed that basal transcription required the binding of hepatic nuclear factor 1 (HNF-1) to its cognate sequence. Furthermore, mutation of this HNF-1 binding site resulted in complete loss of luciferase expression, even in the context of the whole promoter. Additionally, small interfering RNA knockdown of both members of the HNF-1 family, HNF-1alpha and HNF-1beta, resulted in a significant decline in SVCT1 transcription. Together, these data suggest that HNF-1alpha and/or HNF-1beta binding is required for SVCT1 expression and may be involved in the coordinate regulation of whole body vitamin C status.
Collapse
Affiliation(s)
- Alexander J Michels
- Linus Pauling Institute and the Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
| | | |
Collapse
|
34
|
Neel EAA, O'Dell LA, Chrzanowski W, Smith ME, Knowles JC. Control of surface free energy in titanium doped phosphate based glasses by co-doping with zinc. J Biomed Mater Res B Appl Biomater 2009; 89:392-407. [PMID: 18837445 DOI: 10.1002/jbm.b.31227] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To significantly improve the biocompatibility of titanium doped phosphate based glasses, codoping with zinc has been attempted. This study investigated the effect of doping a quaternary 15Na(2)O:30CaO:5TiO(2):50P(2)O(5) glass with zinc oxide (1, 3, and 5 mol %) on bulk, structural, surface, and biological properties; the results were compared with glasses free from ZnO and/or TiO(2). ZnO as adjunct to TiO(2) was effective in changing density, interchain bond forces, degradation behavior, and ions released from the degrading glasses. Incorporation of both TiO(2) and ZnO in T5Z1, T5Z3, and T5Z5 glasses reduced the level of Zn(2+) release by two to three orders of magnitude compared with glasses containing ZnO only (Z5). (31)P NMR results for T5Z1, T5Z3, and T5Z5 glasses showed the presence of Q(3) species suggesting that the TiO(2) is acting as a network former, and the phosphate network becomes slightly more connected with increasing ZnO incorporation. Regardless of their relative lower hydrophilicity and surface reactivity compared with the control glass free from TiO(2) and ZnO (T0Z0), these glasses have significantly higher surface reactivity compared with Thermanox. This has been also reflected in the maintenance of >98% viable Osteoblasts, proliferation rate, and expression level of osteoblastic marker genes in a comparable manner to Thermanox and T5 glasses, particularly T5Z1 and T5Z3 glasses. However, T0Z0 and Z5 glasses showed significantly reduced viability compared to Thermanox. Therefore, it can be concluded that ZnO doped titanium phosphate glasses, T5Z1 and T5Z3 in particular, can be promising substrates for bone tissue engineering applications.
Collapse
Affiliation(s)
- Ensanya Ali Abou Neel
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London WC1X 8LD, United Kingdom
| | - Luke Austin O'Dell
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Wojciech Chrzanowski
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London WC1X 8LD, United Kingdom
| | - Mark Edmund Smith
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Jonathan Campbell Knowles
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London WC1X 8LD, United Kingdom
| |
Collapse
|
35
|
Chi X, May JM. Oxidized lipoprotein induces the macrophage ascorbate transporter (SVCT2): protection by intracellular ascorbate against oxidant stress and apoptosis. Arch Biochem Biophys 2009; 485:174-82. [PMID: 19254685 PMCID: PMC3722556 DOI: 10.1016/j.abb.2009.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 02/13/2009] [Accepted: 02/22/2009] [Indexed: 11/25/2022]
Abstract
To assess whether ascorbic acid decreases the cytotoxicity of oxidized human low density lipoprotein (oxLDL) in cells involved in atherosclerosis, its interaction with oxLDL was studied in murine RAW264.7 macrophages. Macrophages took up ascorbate to millimolar intracellular concentrations and retained it with little loss over 18h in culture. Culture of the macrophages with oxLDL enhanced ascorbate uptake. This was associated with increased expression of the ascorbate transporter (SVCT2), which was prevented by ascorbate and by inhibiting the NF-kappaB pathway. Culture of RAW264.7 macrophages with oxLDL increased intracellular dihydrofluorescein oxidation and lipid peroxidation, both of which were decreased by intracellular ascorbate. Ascorbate also protected the cells against oxLDL-induced cytotoxicity and apoptosis, but it did not affect macrophage accumulation of lipid from oxLDL or oxLDL-induced increases in macrophage cytokine secretion. These results suggest that ascorbate protects macrophages against oxLDL-induced oxidant stress and subsequent apoptotic death without impairing their function.
Collapse
Affiliation(s)
- Xiumei Chi
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303
| | - James M. May
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303
| |
Collapse
|
36
|
Qiao H, May JM. Macrophage differentiation increases expression of the ascorbate transporter (SVCT2). Free Radic Biol Med 2009; 46:1221-32. [PMID: 19232538 PMCID: PMC3732409 DOI: 10.1016/j.freeradbiomed.2009.02.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 01/24/2009] [Accepted: 02/05/2009] [Indexed: 12/11/2022]
Abstract
To determine whether macrophage differentiation involves increased uptake of vitamin C, or ascorbic acid, we assessed the expression and function of its transporter SVCT2 during phorbol ester-induced differentiation of human-derived THP-1 monocytes. Induction of THP-1 monocyte differentiation by phorbol 12-myristate 13-acetate (PMA) markedly increased SVCT2 mRNA, protein, and function. When ascorbate was present during PMA-induced differentiation, the increase in SVCT2 protein expression was inhibited, but differentiation was enhanced. PMA-induced SVCT2 protein expression was blocked by inhibitors of protein kinase C (PKC), with most of the affect due to the PKCbetaI and betaII isoforms. Activation of MEK/ERK was sustained up to 48 h after PMA treatment, and the inhibitors completely blocked PMA-stimulated SVCT2 protein expression, indicating an exclusive role for the classical MAP kinase pathway. However, inhibitors of NF-kappaB activation, NADPH oxidase inhibitors, and several antioxidants also partially prevented SVCT2 induction, suggesting diverse distal routes for control of SVCT2 transcription. Both known promoters for the SVCT2 were involved in these effects. In conclusion, PMA-induced monocyte-macrophage differentiation is enhanced by ascorbate and associated with increased expression and function of the SVCT2 protein through a pathway involving sustained activation of PKCbetaI/II, MAP kinase, NADPH oxidase, and NF-kappaB.
Collapse
Affiliation(s)
- Huan Qiao
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA
| | - James M. May
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA
| |
Collapse
|
37
|
Rivas CI, Zúñiga FA, Salas-Burgos A, Mardones L, Ormazabal V, Vera JC. Vitamin C transporters. J Physiol Biochem 2008; 64:357-75. [DOI: 10.1007/bf03174092] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
38
|
Gournas C, Papageorgiou I, Diallinas G. The nucleobase–ascorbate transporter (NAT) family: genomics, evolution, structure–function relationships and physiological role. MOLECULAR BIOSYSTEMS 2008; 4:404-16. [PMID: 18414738 DOI: 10.1039/b719777b] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Christos Gournas
- Faculty of Biology, Department of Botany, University of Athens, Panepistimioupolis, Athens, Greece
| | | | | |
Collapse
|
39
|
Thurnham DI. An overview of interactions between micronutrients and of micronutrients with drugs, genes and immune mechanisms. Nutr Res Rev 2007; 17:211-40. [DOI: 10.1079/nrr200486] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AbstractThe objective of the present review is to examine critically the consequences of interactions that micronutrients undergo with nutrients and non-nutrients (mainly prescribed medicines) in diets and lifestyle factors (smoking, tea and alcohol consumption). In addition, the review describes recent work on interactions between nutrients and genes, the influence of gene polymorphisms on micronutrients, the impact of immune responses on micronutrients and specific interactions of antioxidant micronutrients in disease processes to minimise potential pro-oxidant damage.
Collapse
|
40
|
Savini I, Rossi A, Catani MV, Ceci R, Avigliano L. Redox regulation of vitamin C transporter SVCT2 in C2C12 myotubes. Biochem Biophys Res Commun 2007; 361:385-90. [PMID: 17643393 DOI: 10.1016/j.bbrc.2007.07.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 07/04/2007] [Indexed: 10/23/2022]
Abstract
We have previously demonstrated that skeletal muscle cells possess efficient systems for vitamin C accumulation; in particular, the SVCT2 transporter for ascorbic acid uptake seems to play a crucial role. In this study, we investigated the regulatory mechanism(s) accounting for SVCT2 activity in C2C12 myotubes. We found that transcription of the SVCT2 gene could be positively or negatively modulated by the presence of oxidant (H(2)O(2)) or antioxidant (lipoate) compounds, respectively. This redox-mediated regulation of SVCT2 expression seemed to be achieved via AP-1 and NF-kappaB signaling. Our findings could be relevant in skeletal muscle, where reactive oxygen species, naturally produced during physical exercise, can induce muscle damage. Thus, the redox-sensitive SVCT2 expression can be placed among the adaptive responses induced by contractile activity.
Collapse
Affiliation(s)
- Isabella Savini
- Department of Experimental Medicine & Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | | | | | | | | |
Collapse
|
41
|
Wu X, Zeng LH, Taniguchi T, Xie QM. Activation of PKA and phosphorylation of sodium-dependent vitamin C transporter 2 by prostaglandin E2 promote osteoblast-like differentiation in MC3T3-E1 cells. Cell Death Differ 2007; 14:1792-801. [PMID: 17585336 DOI: 10.1038/sj.cdd.4402190] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Sodium-dependent vitamin C transporter (SVCT) 2-mediated L-ascorbic acid (AA) uptake is required in osteoblast-like differentiation of MC3T3-E1 cells, and prostaglandin E2 (PGE2) is among the most important local factors in bone formation, but the detailed mechanism by which PGE2 induces osteoblast differentiation remains obscure. We revealed that PGE2 induced AA uptake and osteoblast-like differential markers including alkaline phosphatase, collagen, osteocalcin expression, and mineralization in MC3T3-E1 cells. Inhibition of AA uptake by SVCT2 short isoform functioning as a dominant-negative mutant not only robustly attenuated PGE2-induced markers expression and mineralization, but also decreased their basal levels. However, upregulation of AA uptake resulted from PGE2-induced plasma membrane translocation of cytoplasm SVCT2, and this effect was abolished by pretreatment with EP4 receptor antagonist, AH-23848B or cAMP-dependent protein kinase A (PKA) inhibitor, H-89. Moreover, we showed SVCT2 physically interacted with PKA in immunoprecipitates, and PKA phosphorylated SVCT2 in vitro and in intact cells at Ser402 and Ser639 sites; however, mutation of Ser402 or/and Ser639 in SVCT2 severely diminished SVCT2 translocation in response to PGE2. Together, these results suggest that PGE2-induced SVCT2 plasma membrane translocation through EP4 receptor and subsequent phosphorylation of SVCT2 at Ser402 and Ser639 sites by PKA results in an increase of AA uptake and consequent promotion of osteoblast-like differentiation in MC3T3-E1 cells.
Collapse
Affiliation(s)
- X Wu
- Zhejiang Respiratory Drugs Research Laboratory of State Foods and Drugs Administration of China, Medical School of Zhejiang University, No. 388 Yuhangtang Road, Hangzhou 310058, China
| | | | | | | |
Collapse
|
42
|
Savini I, Rossi A, Pierro C, Avigliano L, Catani MV. SVCT1 and SVCT2: key proteins for vitamin C uptake. Amino Acids 2007; 34:347-55. [PMID: 17541511 DOI: 10.1007/s00726-007-0555-7] [Citation(s) in RCA: 242] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 04/18/2007] [Indexed: 12/13/2022]
Abstract
Vitamin C is accumulated in mammalian cells by two types of proteins: sodium-ascorbate co-transporters (SVCTs) and hexose transporters (GLUTs); in particular, SVCTs actively import ascorbate, the reduced form of this vitamin. SVCTs are surface glycoproteins encoded by two different genes, very similar in structure. They show distinct tissue distribution and functional characteristics, which indicate different physiological roles. SVCT1 is involved in whole-body homeostasis of vitamin C, while SVCT2 protects metabolically active cells against oxidative stress. Regulation at mRNA or protein level may serve for preferential accumulation of ascorbic acid at sites where it is needed. This review will summarize the present knowledge on structure, function and regulation of the SVCT transporters. Understanding the physiological role of SVCT1 and SVCT2 may lead to develop new therapeutic strategies to control intracellular vitamin C content or to promote tissue-specific delivery of vitamin C-drug conjugates.
Collapse
Affiliation(s)
- I Savini
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Rome, Italy.
| | | | | | | | | |
Collapse
|
43
|
Cerovic A, Miletic I, Sobajic S, Blagojevic D, Radusinovic M, El-Sohemy A. Effects of zinc on the mineralization of bone nodules from human osteoblast-like cells. Biol Trace Elem Res 2007; 116:61-71. [PMID: 17634628 DOI: 10.1007/bf02685919] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 09/08/2006] [Accepted: 10/24/2006] [Indexed: 10/22/2022]
Abstract
Zinc is an important mineral that is required for normal bone development. However, the direct effects of zinc on the mineralization of bone cells of human origin are not clear. The objective of this study was to determine the effects of zinc on the differentiation of SaOS-2 human osteoblastlike cells and the formation of mineralized bone nodules. Cells were cultured for 8 d and then transferred to zinc-free medium and treated with varying concentrations (0-50 microM) of zinc. Alkaline phosphatase (ALP) activity was used as a measure of osteoblast differentiation, and bone nodules were detected by von Kossa staining. After 4, 6, and 8 d of treatment, zinc increased ALP activity at 1 and 10 microM, but decreased activity at 50 microM. After 9 d of treatment, zinc increased both the number and area of mineralized bone nodules at low concentrations (1 and 10 microM), but decreased both at higher concentrations (25 and 50 microM). These findings demonstrate that zinc has biphasic effects on the differentiation and mineralization of human osteoblast-like cells.
Collapse
Affiliation(s)
- Aleksandra Cerovic
- Department of Bromatology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | | | | | | | | | | |
Collapse
|
44
|
Savini I, Catani MV, Arnone R, Rossi A, Frega G, Del Principe D, Avigliano L. Translational control of the ascorbic acid transporter SVCT2 in human platelets. Free Radic Biol Med 2007; 42:608-16. [PMID: 17291984 DOI: 10.1016/j.freeradbiomed.2006.11.028] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Revised: 11/23/2006] [Accepted: 11/28/2006] [Indexed: 12/15/2022]
Abstract
Reactive oxygen species (ROS) and redox state have emerged as physiological mediators, controlling blood coagulation and thrombosis. The redox balance is obviously linked to the presence of antioxidants; in particular, vitamin C appears to be a key modulator of platelet oxidative state, since these cells physiologically accumulate ascorbic acid and, moreover, platelet ascorbate plays a role during aggregation. Here, we showed that platelets could compensate for fluctuations in ascorbate levels by modulating the expression of the Na+-dependent transporter SVCT2. Furthermore, the use of anucleated cells demonstrated, for the first time, that SVCT2 expression could be regulated at the translational level. The control of ascorbic acid uptake, through regulation of its carrier, was not only related to substrate availability, but it also occurred during platelet activation, which was accompanied by vitamin C deprivation and alteration in the redox state. Finally, we showed that changes in intracellular ascorbic acid content had physiological relevance, since they modulate the surface sulfhydryl content and the thrombus viscoelastic properties. Beside its role during aggregation, vitamin C may also have important effects during postaggregatory events.
Collapse
Affiliation(s)
- Isabella Savini
- Department of Experimental Medicine & Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Roma, Italy
| | | | | | | | | | | | | |
Collapse
|
45
|
Salih V, Patel A, Knowles JC. Zinc-containing phosphate-based glasses for tissue engineering. Biomed Mater 2007; 2:11-20. [PMID: 18458428 DOI: 10.1088/1748-6041/2/1/003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
It has been shown that the addition of zinc to hydroxyapatite promotes osteoblast cell adhesion (Ishaug et al 1994 J. Biomed. Mater. Res. A 28 1445-53). Therefore, this study presents a series of phosphate-based glass compositions that contain varying amounts of zinc in order to promote osteoblast cell adhesion. The compositions investigated were P(50)Ca((40-x))Na(10) where x = 0, 1, 2, 3, 4 and 5 mol%. The dissolution rate and effect on pH of glass discs were investigated and ion release from the glass discs was examined in distilled water at 37 degrees C after 1, 2, 3, 4 and 7 days. The attachment of osteoblast-like cells (HOB) was observed by SEM on the glass discs. A linear decrease in the %mass of the glass discs was observed for all compositions for the duration of the study. The dissolution rates were similar for all the compositions. After 7 days, a mass loss of 3-6% was observed for all the compositions. The pH of distilled water decreased to a range of pH 4.5-5.5 from pH 7 after 1 day, and remained in this range for the duration of the study. The composition containing 0 mol% Zn reduced the pH to a lesser extent than the composition containing the highest amount of Zn. Furthermore, Zn(2+) ion release was observed from all the Zn-containing compositions. These glass compositions may therefore be suitable for tissue engineering applications.
Collapse
Affiliation(s)
- V Salih
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, 256 Gray's Inn Road, London, WC1X 8LD, UK
| | | | | |
Collapse
|
46
|
Tupe RS, Chiplonkar SA, Agte VV. Changes in zinc uptake in response to ascorbic acid and folic acid in rat liver slices under normal and oxidative stress conditions. Biofactors 2007; 30:27-34. [PMID: 18198399 DOI: 10.1002/biof.5520300104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Zinc plays a dual role, as an integral part of metabolic machinery and in defense against reactive oxygen species. Hepatocytes are important sites for zinc metabolism for synthesis of zinc metalloproteins and maintaining its homeostasis. However, the factors influencing post absorptive zinc metabolism under normal and oxidative stress (OS) conditions are not well understood. Using rat liver slices, we conducted a series of four in vitro zinc uptake experiments to study influence of ascorbic acid and folic acid in normal and oxidative stress conditions with Zn concentrations representing deficient to excess states (7.7-30.7 millimole/L). Zinc uptakes under OS at these four zinc levels were lower than the normal conditions. Folic acid showed significant inhibitory effect on zinc uptake under both normal and OS conditions in a dose response manner. Nevertheless, dose response of ascorbic acid at four zinc levels indicated its marked enhancing effect under OS condition. Differences in zinc uptake trend lines between the normal and OS conditions for interaction of both the vitamins narrowed down as the zinc levels increased. Our results suggest that folic acid causes inhibitory effect, while ascorbic acid may be protective in OS with reference to zinc uptake.
Collapse
Affiliation(s)
- R S Tupe
- Agharkar Research Institute, Pune, India
| | | | | |
Collapse
|
47
|
Mun GH, Kim MJ, Lee JH, Kim HJ, Chung YH, Chung YB, Kang JS, Hwang YI, Oh SH, Kim JG, Hwang DH, Shin DH, Lee WJ. Immunohistochemical study of the distribution of sodium-dependent vitamin C transporters in adult rat brain. J Neurosci Res 2006; 83:919-28. [PMID: 16477646 DOI: 10.1002/jnr.20751] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Sodium-dependent vitamin C transporters (SVCTs) is known to transport the reduced form of ascorbic acid into the cell, whereas the oxidized form of vitamin C (VC) is moved through a facilitative sugar transporter, such as glucose transporter (GLUT). With regard to the distribution of SVCT1 and -2 within the various organs, they were reported to be expressed in different types of cells. Especially in the central nervous system, only SVCT2 mRNA was expressed mainly in neurons and some types of neuroglial cells. However, data on the expression of SVCT proteins in the brain are scant. Therefore, we tried to develop comprehensive data on the distribution of SVCT proteins in adult rat brain by using immunohistochemical techniques for the first time. In our study, SVCT2 immunoreactivities (IRs) were intensely localized in the neurons of cerebral cortex, hippocampus, and Purkinje cells of cerebellum, and much weaker SVCT2 IRs were found in the other brain regions. Judging from double-immunohistochemical data, most of the cells expressing SVCT2 IRs were likely to be neurons or microglia, even though the cells in choroids plexus or ependymal cells around the ventricles also exhibited SVCT2 IRs. Complete mapping of the distribution of SVCT2 IRs was available by using a semiquantitative method. The subcellular localization of SVCT proteins is necessary for understanding the exact role of the protein, so the current overall mapping of SVCT IRs in the rat brain could be the basis for further studies on related subjects.
Collapse
Affiliation(s)
- Ga Hee Mun
- Department of Anatomy, Seoul National University College of Medicine, Seoul, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Savini I, Catani MV, Duranti G, Ceci R, Sabatini S, Avigliano L. Vitamin C homeostasis in skeletal muscle cells. Free Radic Biol Med 2005; 38:898-907. [PMID: 15749386 DOI: 10.1016/j.freeradbiomed.2004.12.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Revised: 10/22/2004] [Accepted: 12/08/2004] [Indexed: 10/26/2022]
Abstract
In skeletal muscle, vitamin C not only enhances carnitine biosynthesis but also protects cells against ROS generation induced by physical exercise. The ability to take up both ascorbic and dehydroascorbic acid from the extracellular environment, together with the ability to recycle the intracellular vitamin, maintains high cellular stores of ascorbate. In this study, we examined vitamin C transport and recycling, by using the mouse C2C12 and rat L6C5 muscle cell lines, which exhibit different sensitivity to oxidative stress and GSH metabolism. We found that: (1) both cell lines express SVCT2, whereas SVCT1 is expressed at very low levels only in proliferating L6C5 cells; furthermore L6C5 myoblasts are more efficient in ascorbic acid transport than C2C12 myoblasts; (2) C2C12 cells are more efficient in dehydroascorbic acid transport and ascorbyl free radical/dehydroascorbic acid reduction; (3) differentiation is paralleled by decreased ascorbic acid and dehydroascorbic acid transport and reduction and increased ascorbyl free radical reduction; (4) differentiated cells are more responsive to oxidative stress induced by glutathione depletion; indeed, myotubes showed increased SVCT2 expression and thioredoxin reductase-mediated dehydroascorbic acid reduction. From our data, SVCT2 and NADPH-thioredoxin-dependent DHA reduction appears to belong to an inducible system activated in response to oxidative stress.
Collapse
Affiliation(s)
- Isabella Savini
- Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
| | | | | | | | | | | |
Collapse
|
49
|
Wu X, Itoh N, Taniguchi T, Hirano J, Nakanishi T, Tanaka K. Stimulation of differentiation in sodium-dependent vitamin C transporter 2 overexpressing MC3T3-E1 osteoblasts. Biochem Biophys Res Commun 2004; 317:1159-64. [PMID: 15094391 DOI: 10.1016/j.bbrc.2004.03.158] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Indexed: 10/26/2022]
Abstract
Sodium-dependent vitamin C transporter (SVCT) 2 facilitates reduced ascorbic acid (AA) transport in MC3T3-E1 osteoblasts. Our previous studies suggested that Zn-induced osteoblast differentiation and Ca2+-, PO4(3-)-stimulated osteopontin (OPN) expression might result from their up-regulation effect on SVCT2 expression and AA uptake. Here, we investigated the role of SVCT2 on osteoblast differentiation by using SVCT2-overexpressing cells. Two clones of SVCT2-introduced cells overexpressed SVCT2 mRNA by 2.8- and 3.1-fold those of control cells, which resulted in obvious increase of AA uptake by 2.1- and 2.4-fold in Vmax with no change in Km. Alkaline phosphatase activity, hydroxyproline content significantly increased in SVCT2-overexpressing cells, and the induction of OPN mRNA was through up-regulation of OPN promoter activity by SVCT2 overexpression. Moreover, SVCT2-overexpressing cells exhibited more ability to promote mineralization and increase calcium deposition under the stimulation of 5 mM beta-glycerophosphate. These findings indicate that SVCT2 stimulates osteoblast differentiation and mineralization.
Collapse
Affiliation(s)
- Ximei Wu
- Department of Toxicology, Graduate School of Pharmaceutical Sciences, Osaka University, Osaka 565-0871, Japan
| | | | | | | | | | | |
Collapse
|