151
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Park GB, Hur DY, Kim YS, Lee HK, Yang JW, Kim D. TLR3/TRIF signalling pathway regulates IL-32 and IFN-β secretion through activation of RIP-1 and TRAF in the human cornea. J Cell Mol Med 2015; 19:1042-54. [PMID: 25754842 PMCID: PMC4420606 DOI: 10.1111/jcmm.12495] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/20/2014] [Indexed: 01/07/2023] Open
Abstract
Toll-like receptor-3 (TLR3) and RNA helicase retinoic-acid-inducible protein-1 (RIG-I) serve as cytoplasmic sensors for viral RNA components. In this study, we investigated how the TLR3 and RIG-I signalling pathway was stimulated by viral infection to produce interleukin (IL)-32-mediated pro-inflammatory cytokines and type I interferon in the corneal epithelium using Epstein-Barr virus (EBV)-infected human cornea epithelial cells (HCECs/EBV) as a model of viral keratitis. Increased TLR3 and RIG-I that are responded to EBV-encoded RNA 1 and 2 (EBER1 and EBER2) induced the secretion of IL-32-mediated pro-inflammatory cytokines and IFN-β through up-regulation of TRIF/TRAF family proteins or RIP-1. TRIF silencing or TLR3 inhibitors more efficiently inhibited sequential phosphorylation of TAK1, TBK1, NF-κB and IRFs to produce pro-inflammatory cytokines and IFN-β than RIG-I-siRNA transfection in HCECs/EBV. Blockade of RIP-1, which connects the TLR3 and RIG-I pathways, significantly blocked the TLR3/TRIF-mediated and RIG-I-mediated pro-inflammatory cytokines and IFN-β production in HCECs/EBV. These findings demonstrate that TLR3/TRIF-dependent signalling pathway against viral RNA might be a main target to control inflammation and anti-viral responses in the ocular surface.
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Affiliation(s)
- Ga Bin Park
- Department of Anatomy, Inje University College of MedicineBusan, Korea
- Ocular Neovascular disease Research Center, Inje University Busan Paik HospitalBusan, Korea
| | - Dae Young Hur
- Department of Anatomy, Inje University College of MedicineBusan, Korea
- Ocular Neovascular disease Research Center, Inje University Busan Paik HospitalBusan, Korea
| | - Yeong Seok Kim
- Department of Anatomy, Inje University College of MedicineBusan, Korea
| | - Hyun-Kyung Lee
- Department of Internal Medicine, Inje University Busan Paik HospitalBusan, Korea
| | - Jae Wook Yang
- Ocular Neovascular disease Research Center, Inje University Busan Paik HospitalBusan, Korea
- Department of Ophthalmology, Inje University Busan Paik HospitalBusan, Korea
| | - Daejin Kim
- Department of Anatomy, Inje University College of MedicineBusan, Korea
- Ocular Neovascular disease Research Center, Inje University Busan Paik HospitalBusan, Korea
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152
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Kása A, Csortos C, Verin AD. Cytoskeletal mechanisms regulating vascular endothelial barrier function in response to acute lung injury. Tissue Barriers 2015; 3:e974448. [PMID: 25838980 DOI: 10.4161/21688370.2014.974448] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 10/04/2014] [Indexed: 01/11/2023] Open
Abstract
Endothelial cells (EC) form a semi-permeable barrier between the interior space of blood vessels and the underlying tissues. In acute lung injury (ALI) the EC barrier is weakened leading to increased vascular permeability. It is widely accepted that EC barrier integrity is critically dependent upon intact cytoskeletal structure and cell junctions. Edemagenic agonists, like thrombin or endotoxin lipopolysaccharide (LPS), induced cytoskeletal rearrangement, and EC contractile responses leading to disruption of intercellular contacts and EC permeability increase. The highly clinically-relevant cytoskeletal mechanisms of EC barrier dysfunction are currently under intense investigation and will be described and discussed in the current review.
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Key Words
- AJ, adherens junction
- ALI, Acute Lung Injury
- ARDS, Acute Respiratory Distress Syndrome
- CPI-17, PKC potentiated inhibitory protein of 17 kDa
- CaD, caldesmon
- EC, endothelial cells
- GJ, gap junction
- HSP-27, small heat shock actin-capping protein of 27 kDa
- IL, interleukin
- LPS, lipopolysaccharide
- MLC, myosin light chain
- MLCK, Ca2+/calmodulin (CaM) dependent MLC kinase
- MLCP, myosin light chain phosphatase
- MT, microtubules
- MYPT1, myosin phosphatase targeting subunit 1
- PKA, protein kinase A
- PKC, protein kinase C
- SM, smooth muscle
- TJ, tight junction
- TLR4, toll-like receptor 4
- TNFα, tumor necrosis factor α
- acute lung injury
- barrier function
- cytoskeleton
- endothelial junctions
- pulmonary endothelium
- thrombin
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Affiliation(s)
- Anita Kása
- Vascular Biology Center; Georgia Regents University ; Augusta, GA USA
| | - Csilla Csortos
- Department of Medical Chemistry; Faculty of Medicine; University of Debrecen ; Debrecen, Hungary
| | - Alexander D Verin
- Vascular Biology Center; Georgia Regents University ; Augusta, GA USA ; Division of Pulmonary; Medicine Medical College of Georgia; Georgia Regents University; Augusta, GA USA
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153
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Raasch M, Rennert K, Jahn T, Peters S, Henkel T, Huber O, Schulz I, Becker H, Lorkowski S, Funke H, Mosig A. Microfluidically supported biochip design for culture of endothelial cell layers with improved perfusion conditions. Biofabrication 2015; 7:015013. [DOI: 10.1088/1758-5090/7/1/015013] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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154
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Chen L, Liu W, Wang P, Xue Y, Su Q, Zeng C, Shang X. Endophilin-1 regulates blood-brain barrier permeability via EGFR-JNK signaling pathway. Brain Res 2015; 1606:44-53. [PMID: 25721793 DOI: 10.1016/j.brainres.2015.02.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 02/08/2015] [Accepted: 02/10/2015] [Indexed: 10/23/2022]
Abstract
Endophilin-1 (Endo1), a multifunctional protein, is essential for synaptic vesicle endocytosis. However, the role and mechanism of endophilin-1 in blood-brain barrier (BBB) function are still unclear. This study was performed to determine whether endophilin-1 regulated BBB permeability via the EGFR-JNK signaling pathway. In the present study, we found that endophilin-1 over-expression in human cerebral microvascular endothelial cell (hCMEC/D3) increased BBB permeability and meanwhile reduced the expression levels of epidermal growth factor receptor (EGFR), phosphorylated c-Jun N-terminal kinase (p-JNK). While endophilin-1 knockdown led to the contrary results. After JNK inhibitor SP600125 was administered to the endophilin-1 silenced hCMEC/D3 cells, the transendothelial electrical resistance (TEER) value was decreased and the permeability coefficient values to 4kDa and 40kDa FITC-dextran were increased. Results observed by Transmission electron microscopy (TEM) showed that tight junctions (TJs) were opened. Moreover, immunofluorescence and Western blot assays revealed the discontinuous distribution of TJ-associated proteins ZO-1, occludin on cell-cell boundaries and a significant decrease in protein expressing levels. Therefore, these results indicated that endophilin-1 positively regulated BBB permeability via the EGFR-JNK signaling pathway in hCMEC/D3 cells, which would provide an experimental basis for further research on endophilin-1 mediated the opening of BBB.
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Affiliation(s)
- Lin Chen
- Department of Neurology, First Affiliated Hospital, China Medical University, Shenyang 110001, People׳s Republic of China; Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China; Department of Neurology, Hainan Provincial Nongken General Hospital, Haikou 570311, People׳s Republic of China
| | - Wenjing Liu
- Department of Neurology, First Affiliated Hospital, China Medical University, Shenyang 110001, People׳s Republic of China; Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China
| | - Ping Wang
- Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China
| | - Yixue Xue
- Department of Neurobiology, College of Basic Medicine, China Medical University, Shenyang 110001, People׳s Republic of China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang 110001, People׳s Republic of China
| | - Qingjie Su
- Department of Neurology, Hainan Provincial Nongken General Hospital, Haikou 570311, People׳s Republic of China
| | - Chaosheng Zeng
- Department of Neurology, Hainan Provincial Nongken General Hospital, Haikou 570311, People׳s Republic of China
| | - Xiuli Shang
- Department of Neurology, First Affiliated Hospital, China Medical University, Shenyang 110001, People׳s Republic of China.
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155
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Loma P, Guzman-Aranguez A, Perez de Lara MJ, Pintor J. Diadenosine tetraphosphate improves adrenergic anti-glaucomatous drug delivery and efficiency. Exp Eye Res 2015; 134:141-7. [PMID: 25701803 DOI: 10.1016/j.exer.2015.02.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/28/2015] [Accepted: 02/17/2015] [Indexed: 01/24/2023]
Abstract
The effect of the dinucleotide P(1), P(4)-Di (adenosine-5') tetraphosphate (Ap4A) in improving adrenergic anti-glaucomatous delivery by modifying the tight junction proteins of the corneal epithelium was evaluated. Stratified human corneal epithelial cells (HCLE) were treated with Ap4A (100 μM) for 5 min and TJ protein levels and barrier function were analysed by western blotting and transepithelial electrical resistance (TEER), respectively. Western blot experiments showed a significant reduction at 2 h (45% reduction of ZO-1 and 65% reduction of occludin protein levels) as compared to non-treated (control) cells. Two hours after Ap4A treatment, TEER values were significantly reduced (65% as compared to control levels (p < 0.001)), indicating an increase in corneal barrier permeability. Topical application of Ap4A in New Zealand white rabbits two hours before the instillation of the hypotensor compounds (the α2-adrenergic receptor agonist, brimonidine and the β-adrenergic receptor antagonist, timolol), improved the delivery of these compounds to the anterior chamber as well as their hypotensive action on the intraocular pressure. The results obtained showed that, when Ap4A was topically applied two hours before the adrenergic compounds, the concentration of brimonidine in the aqueous humour increased from 64.3 ± 5.3 nM to 240.6 ± 8.6 nM and from 58.9 ± 9.2 nM to 183.7 ± 6.8 nM in the case of timolol, which also produces a more profound effect on IOP. Therefore, Ap4A treatment results in a better entrance of adrenergic anti-glaucomatous compounds within the eye and consequently improved therapeutic efficiency by increasing corneal epithelial barrier permeability.
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Affiliation(s)
- Patricia Loma
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain
| | - Ana Guzman-Aranguez
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain
| | - Maria Jesus Perez de Lara
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain
| | - Jesus Pintor
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain.
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156
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Roundabout 4 regulates blood-tumor barrier permeability through the modulation of ZO-1, Occludin, and Claudin-5 expression. J Neuropathol Exp Neurol 2015; 74:25-37. [PMID: 25470344 DOI: 10.1097/nen.0000000000000146] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The blood-tumor barrier (BTB) restricts the delivery of chemotherapeutic drug molecules to tumor tissues. We found that the endothelial cell (EC) receptor molecule Roundabout 4 (Robo4) is endogenously expressed in human brain microvascular ECs and that it is upregulated in a BTB model of glioma cocultured ECs. Knockdown of Robo4 in this BTB model increased permeability; short hairpin RNA targeting Robo4 (shRobo4) led to decreased transendothelial electric resistance values, increased BTB permeability, and downregulated expression of the EC tight junction proteins ZO-1, occludin, and claudin-5. Roundabout 4 influenced BTB permeability via binding with its ligand, Slit2. Short hairpin RNA targeting Robo4 also increased matrix metalloproteinase-9 (MMP-9) activity and expression in glioma cocultured ECs; pretreatment with the MMP inhibitor GM6001 partially blocked the effects of shRobo4 on the transendothelial electric resistance values and ZO-1 and occludin expression. Short hairpin RNA targeting Robo4 also upregulated the phosphorylation of Src and Erk1/2; the Src inhibitor PP2 and the Erk1/2 inhibitor PD98059 blocked shRobo4-mediated alteration in ZO-1 and occludin expression. Together, our results indicate that knockdown of Robo4 increased BTB permeability by reducing EC tight junction protein expression, and that the Src-Erk1/2-MMP-9 signal pathways are involved in this process. Thus, Robo4 may represent a useful future therapeutic target for enhancing BTB permeability.
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157
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Luo P, Peng H, Li C, Ye Z, Tang H, Tang Y, Chen C, Lou T. Advanced glycation end products induce glomerular endothelial cell hyperpermeability by upregulating matrix metalloproteinase activity. Mol Med Rep 2015; 11:4447-53. [PMID: 25634678 DOI: 10.3892/mmr.2015.3269] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 11/19/2014] [Indexed: 11/05/2022] Open
Abstract
The present study aimed to investigate the effects of advanced glycation end‑products (AGEs) on the permeability of glomerular endothelial cells (GEnCs) and determine whether enhanced permeability was due to degradation of tight junction (TJ) complexes by matrix metalloproteinases (MMPs). Cultured monolayers of GEnCs were exposed to AGEs at different doses and treatment durations in the presence or absence of the organic MMP‑2/9 inhibitor (2R)‑2‑((4‑biphenyl sulfony‑l)amino)‑3‑phenylproprionic acid) (BiPs). Expression of the TJ proteins occludin and claudin‑5 was determined by western blot analysis and immunofluorescence, while the permeability of the GEnCs was measured using transendothelial electrical resistance and by diffusion of 4 kDa fluorescein isothiocyanate (FITC)‑dextran. The activities of MMP‑2 and MMP‑9 were assayed using gelatin zymography. The results indicated that AGE‑treated cultures significantly reduced occludin and claudin‑5 immunoreactivity. Similarly, the surface expression of these proteins was significantly reduced and rows of TJs which normally connect endothelial cells became discontinuous or fractured following AGE exposure. Disruption of TJs was accompanied by significantly reduced transendothelial resistance and hyperpermeability to FITC‑dextran. Treatment with AGEs evoked a dose‑ and time‑dependent upregulation of MMP‑2 and MMP‑9. However, co‑administration of AGEs and BiPS, an inhibitor of MMP‑2/MMP‑9, inhibited the downregulation of occludin and claudin‑5, with a concomitant reversal of GEnC monolayer hyperpermeability. In conclusion, AGEs promoted glomerular hyperpermeability in vitro by the MMP‑mediated disruption of TJs. Chronic elevation of endothelial cell AGEs in diabetes mellitus may contribute to glomerular hyperpermeability by inducing the overexpression of MMPs, which degrade TJs, leading to proteinuria.
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Affiliation(s)
- Pengli Luo
- Department of Nephrology, Affiliated Hospital of Qinghai University, Xining, Qinghai 810001, P.R. China
| | - Hui Peng
- Department of Nephrology, The Third Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510660, P.R. China
| | - Canming Li
- Department of Nephrology, The Third Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510660, P.R. China
| | - Zengchun Ye
- Department of Nephrology, The Third Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510660, P.R. China
| | - Hua Tang
- Department of Nephrology, The Third Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510660, P.R. China
| | - Ying Tang
- Department of Nephrology, The Second Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510000, P.R. China
| | - Cailian Chen
- Department of Nephrology, The Third Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510660, P.R. China
| | - Tanqi Lou
- Department of Nephrology, The Third Affiliated Hospital of Sun Yat‑Sen University, Guangzhou, Guangdong 510660, P.R. China
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158
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Kim J, Kim CS, Lee YM, Sohn E, Jo K, Kim JS. Vaccinium myrtillus extract prevents or delays the onset of diabetes--induced blood-retinal barrier breakdown. Int J Food Sci Nutr 2015; 66:236-42. [PMID: 25582181 DOI: 10.3109/09637486.2014.979319] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Many dietary supplements have been sold through advertising their large number of beneficial effects. The aim of this study was to determine whether bilberries (Vaccinium myrtillus) help to prevent diabetes-induced retinal vascular dysfunction in vivo. V. myrtillus extract (VME; 100 mg/kg) was orally administered to streptozotocin-induced diabetic rats for 6 weeks. All diabetic rats exhibited hyperglycemia, and VME did not affect the blood glucose levels and body weight during the experiments. In the fluorescein-dextran angiography, the fluorescein leakage was significantly reduced in diabetic rats treated with VME. VME treatment also decreased markers of diabetic retinopathy, such as retinal vascular endothelial growth factor (VEGF) expression and degradation of zonula occludens-1, occludin and claudin-5 in diabetic rats. In conclusion, VME may prevent or delay the onset of early diabetic retinopathy. These findings have important implications for prevention of diabetic retinopathy using a dietary bilberry supplement.
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Affiliation(s)
- Junghyun Kim
- Korean Medicine Based Herbal Drug Development Group, Herbal Medicine Research Division, Korea Institute of Oriental Medicine , Daejeon , South Korea
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159
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Yu Z, Gong C, Lu B, Yang L, Sheng Y, Ji L, Wang Z. Dendrobium chrysotoxum Lindl. alleviates diabetic retinopathy by preventing retinal inflammation and tight junction protein decrease. J Diabetes Res 2015; 2015:518317. [PMID: 25685822 PMCID: PMC4313057 DOI: 10.1155/2015/518317] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/08/2014] [Accepted: 12/16/2014] [Indexed: 12/24/2022] Open
Abstract
Diabetic retinopathy (DR) is a serious complication of diabetes mellitus. This study aimed to observe the alleviation of the ethanol extract of Dendrobium chrysotoxum Lindl. (DC), a traditional Chinese herbal medicine, on DR and its engaged mechanism. After DC (30 or 300 mg/kg) was orally administrated, the breakdown of blood retinal barrier (BRB) in streptozotocin- (STZ-) induced diabetic rats was attenuated by DC. Decreased retinal mRNA expression of tight junction proteins (including occludin and claudin-1) in diabetic rats was also reversed by DC. Western blot analysis and retinal immunofluorescence staining results further confirmed that DC reversed the decreased expression of occludin and claudin-1 proteins in diabetic rats. DC reduced the increased retinal mRNA expressions of intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor α (TNFα), interleukin- (IL-) 6, and IL-1β in diabetic rats. In addition, DC alleviated the increased 1 and phosphorylated p65, IκB, and IκB kinase (IKK) in diabetic rats. DC also reduced the increased serum levels of TNFα, interferon-γ (IFN-γ), IL-6, IL-1β, IL-8, IL-12, IL-2, IL-3, and IL-10 in diabetic rats. Therefore, DC can alleviate DR by inhibiting retinal inflammation and preventing the decrease of tight junction proteins, such as occludin and claudin-1.
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Affiliation(s)
- Zengyang Yu
- The Shanghai Key Laboratory of Complex Prescription and The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Chenyuan Gong
- The Shanghai Key Laboratory of Complex Prescription and The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Bin Lu
- The Shanghai Key Laboratory of Complex Prescription and The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Li Yang
- The Shanghai Key Laboratory of Complex Prescription and The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yuchen Sheng
- Center for Drug Safety Evaluation and Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Lili Ji
- The Shanghai Key Laboratory of Complex Prescription and The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
- *Lili Ji:
| | - Zhengtao Wang
- The Shanghai Key Laboratory of Complex Prescription and The MOE Key Laboratory for Standardization of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
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160
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Loma P, Guzman-Aranguez A, Pérez de Lara MJ, Pintor J. Diadenosine tetraphosphate induces tight junction disassembly thus increasing corneal epithelial permeability. Br J Pharmacol 2014; 172:1045-58. [PMID: 25297531 DOI: 10.1111/bph.12972] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 09/26/2014] [Accepted: 09/29/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Here, we have studied the effects of the dinucleotide P(1), P(4)-Di (adenosine-5') tetraphosphate (Ap4 A) on corneal barrier function conferred by the tight junction (TJ) proteins and its possible involvement in ocular drug delivery and therapeutic efficiency. EXPERIMENTAL APPROACH Experiments in vitro were performed using human corneal epithelial cells (HCLEs) treated with Ap4 A (100 μM) for 5 min. Western blot analysis and transepithelial electrical resistance (TEER) were performed to study the TJ protein levels and barrier function respectively. Intracellular pathways involved were determined using an ERK inhibitor and P2Y(2) receptor siRNAs. In in vivo assays with New Zealand rabbits, TJ integrity was examined by zonula occludens-1 (ZO-1) staining. The hypotensive compound 5-methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT) was used to assess improved delivery, measuring its levels by HPLC and measuring intraocular pressure using 5-MCA-NAT, P2Y receptor antagonists and P2Y2 siRNAs. KEY RESULTS Two hours after Ap4 A pretreatment, TJ protein levels in HCLE cells were reduced around 40% compared with control. TEER values were significantly reduced at 2 and 4 h (68 and 52% respectively). TJ reduction and ERK activation were blocked by the ERK inhibitor U012 and P2Y(2) siRNAs. In vivo, topical application of Ap4 A disrupted ZO-1 membrane distribution. 5-MCA-NAT levels in the aqueous humour were higher when Ap4 A was previously instilled and its hypotensive effect was also increased. This action was reversed by P2Y receptor antagonists and P2Y(2) siRNA. CONCLUSIONS AND IMPLICATIONS Ap4 A increased corneal epithelial barrier permeability. Its application could improve ocular drug delivery and consequently therapeutic efficiency.
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Affiliation(s)
- P Loma
- Department of Biochemistry and Molecular Biology IV, Faculty of Optics and Optometry, Universidad Complutense de Madrid, Spain
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161
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Lejeune M, Moreau F, Chadee K. Loss of EP2 receptor subtype in colonic cells compromise epithelial barrier integrity by altering claudin-4. PLoS One 2014; 9:e113270. [PMID: 25396731 PMCID: PMC4232557 DOI: 10.1371/journal.pone.0113270] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 10/26/2014] [Indexed: 01/30/2023] Open
Abstract
Prostaglandin E2 (PGE2) is a bioactive lipid mediator that exerts its biological function through interaction with four different subtypes of E-Prostanoid receptor namely EP1, EP2, EP3 and EP4. It has been known that EP2 receptor is differentially over-expressed in the epithelia of inflamed human colonic mucosa. However, the significance of the differential expression in altering epithelial barrier function is not known. In this study, we used Caco-2 cells expressing EP2 receptor, either high (EP2S) or low (EP2A), as a model epithelia and determined the barrier function of these cell monolayers by measuring the trans epithelial resistance (TER). Basal TER of EP2A (but not EP2S) monolayer was significantly lower suggesting a loss of colonic epithelial barrier integrity. In comparison, the TER of wild type Caco-2 was decreased in response to an EP2 receptor specific antagonist (AH-6809) indicating an important role for EP2 receptor in the maintenance of epithelial barrier function. The decrease TER in EP2A monolayer corresponded with a significant loss of the tight junction (TJ) protein claudin-4 without affecting other major TJ proteins. Similarly, EP2 receptor antagonism/siRNA based silencing significantly decreased claudin-4 expression in EP2S cells. Surprisingly, alteration in claudin-4 was not transcriptionally regulated in EP2A cells but rather undergoes increased proteosomal degradation. Moreover, among the TER compromising cytokines examined (IL-8, IL-1β, TNF-α, IFN-γ) only IFN-γ was significantly up regulated in EP2A cells. However, IFN-γ did not significantly decreased claudin-4 expression in Caco-2 cells indicating no role for IFN-γ in degrading claudin-4. We conclude that differential down-regulation of EP2 receptor play a major role in compromising colonic epithelial barrier function by selectively increasing proteosomal degradation of claudin-4.
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Affiliation(s)
- Manigandan Lejeune
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - France Moreau
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| | - Kris Chadee
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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162
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Nouri M, Bredberg A, Weström B, Lavasani S. Intestinal barrier dysfunction develops at the onset of experimental autoimmune encephalomyelitis, and can be induced by adoptive transfer of auto-reactive T cells. PLoS One 2014; 9:e106335. [PMID: 25184418 PMCID: PMC4153638 DOI: 10.1371/journal.pone.0106335] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 08/05/2014] [Indexed: 12/13/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system with a pathogenesis involving a dysfunctional blood-brain barrier and myelin-specific, autoreactive T cells. Although the commensal microbiota seems to affect its pathogenesis, regulation of the interactions between luminal antigens and mucosal immune elements remains unclear. Herein, we investigated whether the intestinal mucosal barrier is also targeted in this disease. Experimental autoimmune encephalomyelitis (EAE), the prototypic animal model of MS, was induced either by active immunization or by adoptive transfer of autoreactive T cells isolated from these mice. We show increased intestinal permeability, overexpression of the tight junction protein zonulin and alterations in intestinal morphology (increased crypt depth and thickness of the submucosa and muscularis layers). These intestinal manifestations were seen at 7 days (i.e., preceding the onset of neurological symptoms) and at 14 days (i.e., at the stage of paralysis) after immunization. We also demonstrate an increased infiltration of proinflammatory Th1/Th17 cells and a reduced regulatory T cell number in the gut lamina propria, Peyer's patches and mesenteric lymph nodes. Adoptive transfer to healthy mice of encephalitogenic T cells, isolated from EAE-diseased animals, led to intestinal changes similar to those resulting from the immunization procedure. Our findings show that disruption of intestinal homeostasis is an early and immune-mediated event in EAE. We propose that this intestinal dysfunction may act to support disease progression, and thus represent a potential therapeutic target in MS. In particular, an increased understanding of the regulation of tight junctions at the blood-brain barrier and in the intestinal wall may be crucial for design of future innovative therapies.
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Affiliation(s)
- Mehrnaz Nouri
- Department of Clinical Sciences, Clinical Research Centre, Surgery Research Unit, Lund University, Malmö, Sweden
- Department of Biology, Lund University, Lund, Sweden
| | - Anders Bredberg
- ImmuneBiotech AB, Lund Life Science Incubator, Medicon Village, Lund, Sweden
- Department of Laboratory Medicine, Section of Medical Microbiology, Lund University, Malmö, Sweden
| | - Björn Weström
- Department of Biology, Lund University, Lund, Sweden
| | - Shahram Lavasani
- Department of Biology, Lund University, Lund, Sweden
- ImmuneBiotech AB, Lund Life Science Incubator, Medicon Village, Lund, Sweden
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163
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Liu M, Gao R, Meng Q, Zhang Y, Bi C, Shan A. Toxic effects of maternal zearalenone exposure on intestinal oxidative stress, barrier function, immunological and morphological changes in rats. PLoS One 2014; 9:e106412. [PMID: 25180673 PMCID: PMC4152245 DOI: 10.1371/journal.pone.0106412] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 08/06/2014] [Indexed: 01/25/2023] Open
Abstract
The present study was conducted to investigate the effects of maternal zearalenone (ZEN) exposure on the intestine of pregnant Sprague-Dawley (SD) rats and its offspring. Ninety-six pregnant SD rats were randomly divided into four groups and were fed with diets containing ZEN at concentrations of 0.3 mg/kg, 48.5 mg/kg, 97.6 mg/kg or 146.0 mg/kg from gestation days (GD) 1 to 7. All rats were fed with mycotoxin-free diet until their offspring were weaned at three weeks of age. The small intestinal fragments from pregnant rats at GD8, weaned dams and pups were collected and studied for toxic effects of ZEN on antioxidant status, immune response, expression of junction proteins, and morphology. The results showed that ZEN induced oxidative stress, affected the villous structure and reduced the expression of junction proteins claudin-4, occludin and connexin43 (Cx43) in a dose-dependent manner in pregnant rats. Different effects on the expression of cytokines were also observed both in mRNA and protein levels in these pregnant groups. Ingestion of high levels of ZEN caused irreversible damage in weaned dams, such as oxidative stress, decreased villi hight and low expression of junction proteins and cytokines. Decreased expression of jejunal interleukin-8 (IL-8) and increased expression of gastrointestinal glutathione peroxidase (GPx2) mRNA were detected in weaned offspring, indicating long-term damage caused by maternal ZEN. We also found that the Nrf2 expression both in mRNA and protein levels were up-regulated in the ZEN-treated groups of pregnant dams and the high-dose of ZEN group of weaned dams. The data indicate that modulation of Nrf2-mediated pathway is one of mechanism via which ZEN affects gut wall antioxidant and inflammatory responses.
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Affiliation(s)
- Min Liu
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, P. R. China
| | - Rui Gao
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, P. R. China
| | - Qingwei Meng
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, P. R. China
| | - Yuanyuan Zhang
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, P. R. China
| | - Chongpeng Bi
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, P. R. China
| | - Anshan Shan
- Institute of Animal Nutrition, Northeast Agricultural University, Harbin, P. R. China
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164
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Witt KA, Sandoval KE. Steroids and the blood-brain barrier: therapeutic implications. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:361-390. [PMID: 25307223 DOI: 10.1016/bs.apha.2014.06.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Steroids have a wide spectrum of impact, serving as fundamental regulators of nearly every physiological process within the human body. Therapeutic applications of steroids are equally broad, with a diverse range of medications and targets. Within the central nervous system (CNS), steroids influence development, memory, behavior, and disease outcomes. Moreover, steroids are well recognized as to their impact on the vascular endothelium. The blood-brain barrier (BBB) at the level of the brain microvascular endothelium serves as the principle interface between the peripheral circulation and the brain. Steroids have been identified to impact several critical properties of the BBB, including cellular efflux mechanisms, nutrient uptake, and tight junction integrity. Such actions not only influence brain homeostasis but also the delivery of CNS-targeted therapeutics. A greater understanding of the respective steroid-BBB interactions may shed further light on the differential treatment outcomes observed across CNS pathologies. In this chapter, we examine the current therapeutic implications of steroids respective to BBB structure and function, with emphasis on glucocorticoids and estrogens.
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Affiliation(s)
- Ken A Witt
- Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University, Edwardsville, Illinois, USA.
| | - Karin E Sandoval
- Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University, Edwardsville, Illinois, USA
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165
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Leontidis G, Al-Diri B, Hunter A. Diabetic retinopathy: current and future methods for early screening from a retinal hemodynamic and geometric approach. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/17469899.2014.945521] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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166
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Kim J, Kim CS, Lee IS, Lee YM, Sohn E, Jo K, Kim JH, Kim JS. Extract of Litsea japonica ameliorates blood-retinal barrier breakdown in db/db mice. Endocrine 2014; 46:462-9. [PMID: 24287793 DOI: 10.1007/s12020-013-0085-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 10/09/2013] [Indexed: 11/29/2022]
Abstract
Loss of blood-retinal barrier (BRB) properties is an important feature in the pathology of diabetic retinopathy. Endothelium integrity is important for the normal vascular function. Litsea japonica (Thunb.) Jussieu is a Korean native plant that is consumed as a vegetable food. In this study, we evaluated the ability of an ethanol extract of L. japonica to prevent retinal vascular leakages in db/db mice, which is an animal model of type II diabetes. L. japonica extracts (LJE, 100 and 250 mg/kg) were administered once a day, orally, for 12 weeks. Vehicle-treated db/db mice exhibited hyperglycemia and retinal vascular leakage. LJE treatment blocked diabetes-induced BRB breakdown and decreased retinal VEGF expression in db/db mice. LJE also inhibited the degradation of occludin, which is an important tight junction protein. These findings support the potential therapeutic usefulness of L. japonica for retinal vascular permeability diseases.
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Affiliation(s)
- Junghyun Kim
- Korean Medicine Based Herbal Drug Development Group, Herbal Medicine Research Division, Korea Institute of Oriental Medicine (KIOM), 1672 Yuseongdaero, Yuseong-gu, Daejeon, 305-811, South Korea
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167
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Engelhardt S, Al-Ahmad AJ, Gassmann M, Ogunshola OO. Hypoxia selectively disrupts brain microvascular endothelial tight junction complexes through a hypoxia-inducible factor-1 (HIF-1) dependent mechanism. J Cell Physiol 2014; 229:1096-105. [PMID: 24375098 DOI: 10.1002/jcp.24544] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/17/2013] [Indexed: 12/25/2022]
Abstract
The blood-brain barrier (BBB) constitutes a critical barrier for the maintenance of central nervous system homeostasis. Brain microvascular endothelial cells line the vessel walls and express tight junction (TJ) complexes that restrict paracellular passage across the BBB, thereby fulfilling a crucial role in ensuring brain function. Hypoxia, an impaired O(2) delivery, is known to cause BBB dysfunction but the mechanisms that drive this disruption remain unclear. This study discloses the relevance of the master regulator of the hypoxic response, hypoxia-inducible factor-1 (HIF-1), in hypoxia-induced barrier disruption using the rat brain endothelial cell line RBE4. Hypoxic exposure rapidly induced stabilization of the HIF-1 oxygen-dependent alpha subunit (HIF-1α) concomitantly with BBB impairment and TJ disruption mainly through delocalization and increased tyrosine phosphorylation of TJ proteins. Similar observations were obtained by normoxic stabilization of HIF-1α using CoCl(2), deferoxamine, and dimethyloxalylglycine underlining the involvement of HIF-1 in barrier dysfunction particularly via TJ alterations. In agreement inhibition of HIF-1 stabilization by 2-methoxyestradiol and YC-1 improved barrier function in hypoxic cells. Overall our data suggests that activation of HIF-1-mediated signaling disrupts TJ resulting in increased BBB permeability.
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Affiliation(s)
- Sabrina Engelhardt
- Vetsuisse Faculty, Institute of Veterinary Physiology & Zurich Center Integrative Physiology (ZIHP), University of Zurich, Zurich, Switzerland
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168
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Alterations of retinal vasculature in cystathionine-β-synthase heterozygous mice: a model of mild to moderate hyperhomocysteinemia. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:2573-85. [PMID: 25016930 DOI: 10.1016/j.ajpath.2014.05.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 04/16/2014] [Accepted: 05/15/2014] [Indexed: 11/21/2022]
Abstract
Mild to moderate hyperhomocysteinemia is prevalent in humans and is implicated in neurovascular diseases, including recently in certain retinal diseases. Herein, we used hyperhomocysteinemic mice deficient in the Cbs gene encoding cystathionine-β-synthase (Cbs(+/-)) to evaluate retinal vascular integrity. The Cbs(+/+) (wild type) and Cbs(+/-) (heterozygous) mice (aged 16 to 52 weeks) were subjected to fluorescein angiography and optical coherence tomography to assess vasculature in vivo. Retinas harvested for cryosectioning or flat mount preparations were subjected to immunofluorescence microscopy to detect blood vessels (isolectin-B4), angiogenesis [anti-vascular endothelial growth factor (VEGF) and anti-CD105], gliosis [anti-glial fibrillary acidic protein (GFAP)], pericytes (anti-neural/glial antigen 2), blood-retinal barrier [anti-zonula occludens protein 1 (ZO-1) and anti-occludin], and hypoxia [anti-pimonidazole hydrochloride (Hypoxyprobe-1)]. Levels of VEGF, GFAP, ZO-1, and occludin were determined by immunoblotting. Results of these analyses showed a mild vascular phenotype in young mice, which progressed with age. Fluorescein angiography revealed progressive neovascularization and vascular leakage in Cbs(+/-) mice; optical coherence tomography confirmed new vessels in the vitreous by 1 year. Immunofluorescence microscopy demonstrated vascular patterns consistent with ischemia, including a capillary-free zone centrally and new vessels with capillary tufts midperipherally in older mice. This was associated with increased VEGF, CD105, and GFAP and decreased ZO-1/occludin levels in the Cbs(+/-) retinas. Retinal vein occlusion was observed in some Cbs(+/-) mouse retinas. We conclude that mild to moderate elevation of homocysteine in Cbs(+/-) mice is accompanied by progressive alterations in retinal vasculature characterized by ischemia, neovascularization, incompetent blood-retinal barrier, and vascular occlusion.
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169
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Caspase-14 expression impairs retinal pigment epithelium barrier function: potential role in diabetic macular edema. BIOMED RESEARCH INTERNATIONAL 2014; 2014:417986. [PMID: 25121097 PMCID: PMC4119899 DOI: 10.1155/2014/417986] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 06/06/2014] [Indexed: 11/17/2022]
Abstract
We recently showed that caspase-14 is a novel molecule in retina with potential role in accelerated vascular cell death during diabetic retinopathy (DR). Here, we evaluated whether caspase-14 is implicated in retinal pigment epithelial cells (RPE) dysfunction under hyperglycemia. The impact of high glucose (HG, 30 mM D-glucose) on caspase-14 expression in human RPE (ARPE-19) cells was tested, which showed significant increase in caspase-14 expression compared with normal glucose (5 mM D-glucose + 25 mM L-glucose). We also evaluated the impact of modulating caspase-14 expression on RPE cells barrier function, phagocytosis, and activation of other caspases using ARPE-19 cells transfected with caspase-14 plasmid or caspase-14 siRNA. We used FITC-dextran flux assay and electric cell substrate impedance sensing (ECIS) to test the changes in RPE cell barrier function. Similar to HG, caspase-14 expression in ARPE-19 cells increased FITC-dextran leakage through the confluent monolayer and decreased the transcellular electrical resistance (TER). These effects of HG were prevented by caspase-14 knockdown. Furthermore, caspase-14 knockdown prevented the HG-induced activation of caspase-1 and caspase-9, the only activated caspases by HG. Phagocytic activity was unaffected by caspase-14 expression. Our results suggest that caspase-14 contributes to RPE cell barrier disruption under hyperglycemic conditions and thus plays a role in the development of diabetic macular edema.
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170
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Li J, Ge R, Zhao C, Tang L, Li J, Li Q. Farrerol regulates occludin expression in hydrogen peroxide-induced EA.hy926 cells by modulating ERK1/2 activity. Eur J Pharmacol 2014; 734:9-14. [DOI: 10.1016/j.ejphar.2014.03.054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 03/19/2014] [Accepted: 03/27/2014] [Indexed: 01/03/2023]
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171
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Jimenez FR, Lewis JB, Belgique ST, Wood TT, Reynolds PR. Developmental lung expression and transcriptional regulation of claudin-6 by TTF-1, Gata-6, and FoxA2. Respir Res 2014; 15:70. [PMID: 24970044 PMCID: PMC4082679 DOI: 10.1186/1465-9921-15-70] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 06/23/2014] [Indexed: 11/10/2022] Open
Abstract
Background Claudins are transmembrane proteins expressed in tight junctions that prevent paracellular transport of extracellular fluid and a variety of other substances. However, the expression profile of Claudin-6 (Cldn6) in the developing lung has not been characterized. Methods and results Cldn6 expression was determined during important periods of lung organogenesis by microarray analysis, qPCR and immunofluorescence. Expression patterns were confirmed to peak at E12.5 and diminish as lung development progressed. Immunofluorescence revealed that Cldn6 was detected in cells that also express TTF-1 and FoxA2, two critical transcriptional regulators of pulmonary branching morphogenesis. Cldn6 was also observed in cells that express Sox2 and Sox9, factors that influence cell differentiation in the proximal and distal lung, respectively. In order to assess transcriptional control of Cldn6, 0.5, 1.0, and 2.0-kb of the proximal murine Cldn6 promoter was ligated into a luciferase reporter and co-transfected with expression vectors for TTF-1 or two of its important transcriptional co-regulators, FoxA2 and Gata-6. In almost every instance, TTF-1, FoxA2, and Gata-6 activated gene transcription in cell lines characteristic of proximal airway epithelium (Beas2B) and distal alveolar epithelium (A-549). Conclusions These data revealed for the first time that Cldn6 might be an important tight junctional component expressed by pulmonary epithelium during lung organogenesis. Furthermore, Cldn6-mediated aspects of cell differentiation may describe mechanisms of lung perturbation coincident with impaired cell junctions and abnormal membrane permeability.
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Affiliation(s)
| | | | | | | | - Paul R Reynolds
- Department of Physiology and Developmental Biology, Brigham Young University, 3054 Life Sciences Building, Provo, UT 84602, USA.
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172
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Liu R, Li JZ, Song JK, Zhou D, Huang C, Bai XY, Xie T, Zhang X, Li YJ, Wu CX, Zhang L, Li L, Zhang TT, Du GH. Pinocembrin improves cognition and protects the neurovascular unit in Alzheimer related deficits. Neurobiol Aging 2014; 35:1275-85. [PMID: 24468471 DOI: 10.1016/j.neurobiolaging.2013.12.031] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 11/13/2013] [Accepted: 12/25/2013] [Indexed: 11/23/2022]
Abstract
Amyloid-β (Aβ) peptides accumulate in the brain and initiate a cascade of pathologic events in Alzheimer's disease. The receptor for advanced glycation end products (RAGE) has been implicated to mediate Aβ-induced perturbations in the neurovascular unit (NVU). We demonstrated that pinocembrin exhibits neuroprotection through inhibition of the Aβ and/or RAGE pathway, but the therapeutic role and mechanism involved are not ascertained. Here, we report that a 3-month treatment with pinocembrin prevents the cognition decline in APP/PS1 transgenic mice without altering Aβ burden and oxidative stress. Instead, pinocembrin is effective in conferring neurovascular protection through maintenance of neuropil ultrastructure, reduction of glial activation and levels of inflammatory mediators, preservation of microvascular function, improving the cholinergic system by conserving the ERK-CREB-BDNF pathway, and modulation of RAGE-mediated transduction. Furthermore, in an in vitro model, pinocembrin provides the NVU protection against fibrillar Aβ₁₋₄₂, accompanied by regulation of neurovascular RAGE pathways. Our findings indicate that pinocembrin improves cognition, at least in part, attributable to the NVU protection, and highlights pinocembrin as a potential therapeutic strategy for the prevention and/or treatment of Alzheimer's disease.
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Affiliation(s)
- Rui Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Jin-ze Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Jun-ke Song
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Dan Zhou
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Chao Huang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Xiao-yu Bai
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Tao Xie
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Xue Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Yong-jie Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China
| | - Cai-xia Wu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China; School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Lan Zhang
- Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Department of Pharmacology, Xuanwu Hospital of Capital Medical University, Beijing Geriatric Medical Research Center, Beijing 100053, PR China
| | - Lin Li
- Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Department of Pharmacology, Xuanwu Hospital of Capital Medical University, Beijing Geriatric Medical Research Center, Beijing 100053, PR China
| | - Tian-tai Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China.
| | - Guan-hua Du
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, P. R. China.
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173
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Enjoji S, Ohama T, Sato K. Regulation of epithelial cell tight junctions by protease-activated receptor 2. J Vet Med Sci 2014; 76:1225-9. [PMID: 24881651 PMCID: PMC4197149 DOI: 10.1292/jvms.14-0191] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A layer of epithelial cells
prevents the invasion of bacteria and the entry of foreign substances into the underlying
tissue. The disruption of epithelial tight junctions initiates and exacerbates
inflammation. However, the precise mechanism underlying the disruption of the epithelial
tight junction remains unclear. The activation of protease-activated receptor 2 (PAR2) by
serine proteases produced by some bacteria and mast cells contributes to inflammation in
many tissues. In the present study, we tested the hypothesis that PAR2 activation affects
the structure and function of tight junctions in Madin-Darby canine kidney (MDCK) cells.
Although the application of a PAR2-activating peptide, PAR2-AP, from the apical side of
MDCK cells failed to modify the transepithelial resistance (TER), its application from the
basal side markedly suppressed the TER. In 3-dimensional cultures of MDCK cells expressing
the mCherry-tagged PAR2, a lateral localization of PAR2 was observed. The application of
PAR2-AP from the basal side changed the localization of the tight junctional protein,
zonula occludin-1. Furthermore, PAR2-AP induced the phosphorylation of p38 MAP kinase. A
p38 MAP kinase inhibitor, SB202190, inhibited PAR2-AP-induced changes in TER. Our results
suggest that the activation of PAR2 leads to the disruption of tight junctions and
increases the barrier permeability through the activation of p38 MAPK, which may cause the
initiation and exacerbation of inflammation.
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Affiliation(s)
- Shuhei Enjoji
- Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan
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174
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Pinton P, Oswald IP. Effect of deoxynivalenol and other Type B trichothecenes on the intestine: a review. Toxins (Basel) 2014; 6:1615-43. [PMID: 24859243 PMCID: PMC4052256 DOI: 10.3390/toxins6051615] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/28/2014] [Accepted: 05/09/2014] [Indexed: 12/23/2022] Open
Abstract
The natural food contaminants, mycotoxins, are regarded as an important risk factor for human and animal health, as up to 25% of the world's crop production may be contaminated. The Fusarium genus produces large quantities of fusariotoxins, among which the trichothecenes are considered as a ubiquitous problem worldwide. The gastrointestinal tract is the first physiological barrier against food contaminants, as well as the first target for these toxicants. An increasing number of studies suggest that intestinal epithelial cells are targets for deoxynivalenol (DON) and other Type B trichothecenes (TCTB). In humans, various adverse digestive symptoms are observed on acute exposure, and in animals, these toxins induce pathological lesions, including necrosis of the intestinal epithelium. They affect the integrity of the intestinal epithelium through alterations in cell morphology and differentiation and in the barrier function. Moreover, DON and TCTB modulate the activity of intestinal epithelium in its role in immune responsiveness. TCTB affect cytokine production by intestinal or immune cells and are supposed to interfere with the cross-talk between epithelial cells and other intestinal immune cells. This review summarizes our current knowledge of the effects of DON and other TCTB on the intestine.
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Affiliation(s)
- Philippe Pinton
- INRA (Institut National de la Recherche Agronomique), UMR1331, Toxalim, Research Centre in Food Toxicology, Toulouse F-31027, France.
| | - Isabelle P Oswald
- INRA (Institut National de la Recherche Agronomique), UMR1331, Toxalim, Research Centre in Food Toxicology, Toulouse F-31027, France.
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175
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Michalec K, Mysiorek C, Kuntz M, Bérézowski V, Szczepankiewicz AA, Wilczyński GM, Cecchelli R, Nałęcz KA. Protein kinase C restricts transport of carnitine by amino acid transporter ATB(0,+) apically localized in the blood-brain barrier. Arch Biochem Biophys 2014; 554:28-35. [PMID: 24823859 DOI: 10.1016/j.abb.2014.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/29/2014] [Accepted: 05/03/2014] [Indexed: 10/25/2022]
Abstract
Carnitine (3-hydroxy-4-trimethylammoniobutyrate) is necessary for transfer of fatty acids through the inner mitochondrial membrane. Carnitine, not synthesized in the brain, is delivered there through the strongly polarized blood-brain barrier (BBB). Expression and presence of two carnitine transporters - organic cation/carnitine transporter (OCTN2) and amino acid transporter B(0,+) (ATB(0,+)) have been demonstrated previously in an in vitro model of the BBB. Due to potential protein kinase C (PKC) phosphorylation sites within ATB(0,+) sequence, the present study verified effects of this kinase on transporter function and localization in the BBB. ATB(0,+) can be regulated by estrogen receptor α and up-regulated in vitro, therefore its presence in vivo was verified with the transmission electron microscopy. The analyses of brain slices demonstrated ATB(0,+) luminal localization in brain capillaries, confirmed by biotinylation experiments in an in vitro model of the BBB. Brain capillary endothelial cells were shown to control carnitine gradient. ATB(0,+) was phosphorylated by PKC, what correlated with inhibition of carnitine transport. PKC activation did not change the amount of ATB(0,+) present in the apical membrane of brain endothelial cells, but resulted in transporter exclusion from raft microdomains. ATB(0,+) inactivation by a lateral movement in plasma membrane after transporter phosphorylation has been postulated.
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Affiliation(s)
- Katarzyna Michalec
- Laboratory of Mechanisms of Transport Through Biomembranes, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Caroline Mysiorek
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Mélanie Kuntz
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Vincent Bérézowski
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Andrzej A Szczepankiewicz
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Grzegorz M Wilczyński
- Laboratory of Molecular and Systemic Neuromorphology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Roméo Cecchelli
- Univ Lille Nord de France, Lille, France; UArtois, LBHE, Lens, France; IMPRT-IFR114, Lille, France
| | - Katarzyna A Nałęcz
- Laboratory of Mechanisms of Transport Through Biomembranes, Nencki Institute of Experimental Biology, Warsaw, Poland.
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176
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Wichapoon B, Punsawad C, Chaisri U, Viriyavejakul P. Glomerular changes and alterations of zonula occludens-1 in the kidneys of Plasmodium falciparum malaria patients. Malar J 2014; 13:176. [PMID: 24884882 PMCID: PMC4023169 DOI: 10.1186/1475-2875-13-176] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/29/2014] [Indexed: 11/10/2022] Open
Abstract
Background The process of cytoadhesion in Plasmodium falciparum malaria infection causes signaling processes that lead to structural and functional changes at the cellular level. Histopathological changes of acute kidney injury (AKI) in P. falciparum malaria often involve glomerular proliferation, thickening of the glomerular basement membrane, acute tubular necrosis, and interstitial inflammation. Focusing on the glomeruli, this study aimed to investigate glomerular and tight junction-associated protein- zonula occludens-1 (ZO-1) changes in P. falciparum malaria patients. Methods Kidney tissues were grouped into P. falciparum with AKI (Cr ≥ 265 μmol/L or 3 mg/dl), P. falciparum without AKI (Cr < 265 μmol/L), and normal kidney tissues (control group). Glomerular cells and the glomerular area were quantified and compared in three experimental groups. The tight junction was investigated immunohistochemically using tight junction-associated protein, ZO-1, protein marker. A further immunofluorescence study was performed in an endothelial cell (EC)-parasitized red blood cell (PRBC) co-culture system, to evaluate the tight junction protein. Results Glomerular cell proliferation was significant in P. falciparum with AKI (Cr ≥ 265 μmol/L). By contrast, the glomerular area decreased significantly. ZO-1 expression was significantly decreased in the AKI group compared with normal kidneys, and in kidney tissues without AKI (p < 0.05). This was further confirmed by the depletion in ZO-1 localization in ECs co-cultured with PRBCs. Conclusions In P. falciparum malaria with AKI, the decrease in glomerular area, despite glomerular cell proliferation, could be due to the collapse of cellular structures secondary to damaged tight junction-associated protein, ZO-1.
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Affiliation(s)
| | | | | | - Parnpen Viriyavejakul
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok 10400, Thailand.
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177
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Endothelial PKCα-MAPK/ERK-phospholipase A2 pathway activation as a response of glioma in a triple culture model. A new role for pericytes? Biochimie 2014; 99:77-87. [PMID: 24287292 DOI: 10.1016/j.biochi.2013.11.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/13/2013] [Indexed: 01/08/2023]
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178
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Su KC, Wu YC, Chen CS, Hung MH, Hsiao YH, Tseng CM, Chang SC, Lee YC, Perng DW. Bile acids increase alveolar epithelial permeability via mitogen-activated protein kinase, cytosolic phospholipase A2 , cyclooxygenase-2, prostaglandin E2 and junctional proteins. Respirology 2014; 18:848-56. [PMID: 23521748 DOI: 10.1111/resp.12086] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 10/13/2012] [Accepted: 01/03/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND AND OBJECTIVE Bile acid (BA) aspiration is associated with various lung diseases. It was hypothesized that BA may induce changes in alveolar epithelium permeability and contribute to the pathogenesis of lung injury. METHODS Human alveolar epithelial cells were grown in monolayer and stimulated with a major component of BA, chenodeoxycholic acid (CDCA). Transepithelial electrical resistance (TER) and paracellular fluxes were measured to assess permeability alteration. Prostaglandin E2 ( PGE2 ) production was measured, and its effect on TER and junctional proteins (JP) was also examined. Reverse transcription polymerase chain reaction and Western blots were used to investigate the expression of messenger RNA and JP. RESULTS CDCA induced significant p38 and c-Jun N-terminal kinase (JNK) phosphorylation, cytosolic phospholipase A2 (cPLA2 ) and cyclooxygenase-2 (COX-2) messenger RNA expression, PGE2 production, TER reduction and decay of JP (including occludin, zonula occludens-1 (ZO-1) and E-cadherin, in which ZO-1 had maximal change). CDCA also increased paracellular fluxes, which was abolished by dexamethasone. Both CDCA and PGE2 contributed to TER reduction in an identical trend and a dose-response manner. PGE2 also reduced ZO-1 expression, which was similar to that observed by CDCA stimulation. Pretreatment with inhibitors of p38 (SB203580), JNK (SP600125), cPLA2 (mepacrine) and COX-2 (NS398) as well as dexamethasone reversed the CDCA-induced PGE2 production, TER reduction and decay of ZO-1. CONCLUSIONS The increase in alveolar permeability was associated with decay of JP. BA may induce permeability alteration through the upregulation of mitogen-activated protein kinase, cPLA2 , COX-2, PGE2 and JP, which may contribute to the pathogenesis of BA-associated lung injury.
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Affiliation(s)
- Kang-Cheng Su
- Institute of Emergency and Critical Care Medicine, School of Medicine, Taipei, Taiwan
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179
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Glucal-conjugated sterols as novel vascular leakage blocker: Structure–activity relationship focusing on the C17-side chain. Eur J Med Chem 2014; 75:184-94. [DOI: 10.1016/j.ejmech.2014.01.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 01/08/2014] [Accepted: 01/14/2014] [Indexed: 12/15/2022]
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180
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Yeganeh B, Wiechec E, Ande SR, Sharma P, Moghadam AR, Post M, Freed DH, Hashemi M, Shojaei S, Zeki AA, Ghavami S. Targeting the mevalonate cascade as a new therapeutic approach in heart disease, cancer and pulmonary disease. Pharmacol Ther 2014; 143:87-110. [PMID: 24582968 DOI: 10.1016/j.pharmthera.2014.02.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/04/2014] [Indexed: 12/21/2022]
Abstract
The cholesterol biosynthesis pathway, also known as the mevalonate (MVA) pathway, is an essential cellular pathway that is involved in diverse cell functions. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) is the rate-limiting step in cholesterol biosynthesis and catalyzes the conversion of HMG-CoA to MVA. Given its role in cholesterol and isoprenoid biosynthesis, the regulation of HMGCR has been intensely investigated. Because all cells require a steady supply of MVA, both the sterol (i.e. cholesterol) and non-sterol (i.e. isoprenoid) products of MVA metabolism exert coordinated feedback regulation on HMGCR through different mechanisms. The proper functioning of HMGCR as the proximal enzyme in the MVA pathway is essential under both normal physiologic conditions and in many diseases given its role in cell cycle pathways and cell proliferation, cholesterol biosynthesis and metabolism, cell cytoskeletal dynamics and stability, cell membrane structure and fluidity, mitochondrial function, proliferation, and cell fate. The blockbuster statin drugs ('statins') directly bind to and inhibit HMGCR, and their use for the past thirty years has revolutionized the treatment of hypercholesterolemia and cardiovascular diseases, in particular coronary heart disease. Initially thought to exert their effects through cholesterol reduction, recent evidence indicates that statins also have pleiotropic immunomodulatory properties independent of cholesterol lowering. In this review we will focus on the therapeutic applications and mechanisms involved in the MVA cascade including Rho GTPase and Rho kinase (ROCK) signaling, statin inhibition of HMGCR, geranylgeranyltransferase (GGTase) inhibition, and farnesyltransferase (FTase) inhibition in cardiovascular disease, pulmonary diseases (e.g. asthma and chronic obstructive pulmonary disease (COPD)), and cancer.
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Affiliation(s)
- Behzad Yeganeh
- Hospital for Sick Children Research Institute, Department of Physiology & Experimental Medicine, University of Toronto, Toronto, Canada
| | - Emilia Wiechec
- Dept. Clinical & Experimental Medicine, Division of Cell Biology & Integrative Regenerative Med. Center (IGEN), Linköping University, Sweden
| | - Sudharsana R Ande
- Department of Internal Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Pawan Sharma
- Department of Physiology & Pharmacology, Snyder Institute for Chronic Diseases, Faculty of Medicine, University of Calgary, 4C46 HRIC, 3280 Hospital Drive NW, Calgary, Alberta, Canada
| | - Adel Rezaei Moghadam
- Scientific Association of Veterinary Medicine, Faculty of Veterinary Medicine, Tabriz Branch, Islamic Azad University, Tabriz, Iran; Young Researchers and Elite Club, Ardabil Branch, Islamic Azad University, Ardabil, Iran
| | - Martin Post
- Hospital for Sick Children Research Institute, Department of Physiology & Experimental Medicine, University of Toronto, Toronto, Canada
| | - Darren H Freed
- Department of Physiology, St. Boniface Research Centre, University of Manitoba, Winnipeg, Canada
| | - Mohammad Hashemi
- Cellular and Molecular Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Shahla Shojaei
- Department of Biochemistry, Recombinant Protein Laboratory, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Amir A Zeki
- U.C. Davis, School of Medicine, U.C. Davis Medical Center, Department of Internal Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Center for Comparative Respiratory Biology & Medicine, Davis, CA, USA.
| | - Saeid Ghavami
- Department of Human Anatomy and Cell Science, St. Boniface Research Centre, Manitoba Institute of Child Health, Biology of Breathing Theme, University of Manitoba, Winnipeg, Canada.
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Akbari P, Braber S, Gremmels H, Koelink PJ, Verheijden KAT, Garssen J, Fink-Gremmels J. Deoxynivalenol: a trigger for intestinal integrity breakdown. FASEB J 2014; 28:2414-29. [PMID: 24568843 DOI: 10.1096/fj.13-238717] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Disintegration of the colonic epithelial barrier is considered a key event in the initiation and progression of inflammatory bowel and celiac disease. As the primary etiology of these diseases remains unknown, we hypothesized that the trichothecene deoxynivalenol (DON), a fungal metabolite found in grain-based human diets, might be one of the triggers resulting in an impairment of the intestinal tight junction network preceding an inflammatory response. Using horizontal impedance measurements, we demonstrate that DON disintegrates a human Caco-2 cell monolayer within <1 h after exposure to concentrations as low as 1.39 μM. This initial trigger is followed by a decrease in transepithelial resistance and an increased permeability of marker molecules, such as lucifer yellow and FITC-labeled dextran. In parallel, the increase in paracellular transport of FITC-dextran is demonstrated in vivo in B6C3F1 mice, challenged orally with DON. In vitro claudin protein levels are decreased and correlated with a displacement within the cells in vitro and in vivo, accompanied by a compensatory up-regulation of mRNA levels of claudins and their binding partner ZO-1. In treated mice, alterations in villus architecture in the entire intestinal tract resemble the disintegration of the epithelial barrier, a characteristic of chronic inflammatory bowel disease.
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Affiliation(s)
- Peyman Akbari
- Division of Veterinary Pharmacy, Pharmacology, and Toxicology, and Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, The Netherlands
| | - Saskia Braber
- Division of Veterinary Pharmacy, Pharmacology, and Toxicology, and
| | - Hendrik Gremmels
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands; and
| | - Pim J Koelink
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, The Netherlands
| | - Kim A T Verheijden
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, The Netherlands
| | - Johan Garssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, The Netherlands; Nutricia Research, Utrecht, The Netherlands
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182
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Che X, Fan XQ, Wang ZL. Mechanism of blood-retinal barrier breakdown induced by HIV-1 (Review). Exp Ther Med 2014; 7:768-772. [PMID: 24660027 PMCID: PMC3961112 DOI: 10.3892/etm.2014.1521] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 01/28/2014] [Indexed: 01/23/2023] Open
Abstract
Human immunodeficiency virus (HIV)-1 has been detected in ocular tissues; however, the mechanism of entry has not been established. It has been hypothesized that the blood-retinal barrier (BRB), a critical guardian against microbial invasion of the eye, may be compromised in the presence of HIV-1 in the eye. In vivo and in vitro model systems have shown that the breach of tight junctions induced by HIV-1-associated factors contributes to the breakdown of the BRB. The present study reviews the mechanism of tight junction disruption, focusing on signaling pathways, the expression of enzymes, including metalloproteinases, and cytokines that affect inflammation. The studied pathways may be potential targets for the prevention of ocular HIV complications.
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Affiliation(s)
- Xin Che
- Department of Ophthalmology, Ninth People's Hospital Affiliated with Shanghai Jiaotong University, Shanghai 200011, P.R. China ; Key Laboratory of Ophthamology, Ninth People's Hospital Affiliated with Shanghai Jiaotong University, Shanghai 200011, P.R. China
| | - Xian-Qun Fan
- Department of Ophthalmology, Ninth People's Hospital Affiliated with Shanghai Jiaotong University, Shanghai 200011, P.R. China
| | - Zhi-Liang Wang
- Department of Ophthalmology, Ninth People's Hospital Affiliated with Shanghai Jiaotong University, Shanghai 200011, P.R. China
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183
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Kopecki Z, Yang GN, Arkell RM, Jackson JE, Melville E, Iwata H, Ludwig RJ, Zillikens D, Murrell DF, Cowin AJ. Flightless I over-expression impairs skin barrier development, function and recovery following skin blistering. J Pathol 2014; 232:541-52. [PMID: 24375017 DOI: 10.1002/path.4323] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 12/10/2013] [Accepted: 12/20/2013] [Indexed: 01/08/2023]
Abstract
Development of an intact epidermis is critical for maintaining the integrity of the skin. Patients with epidermolysis bullosa (EB) experience multiple erosions, which breach the epidermal barrier and lead to increased microbial colocalization of wounds, infections and sepsis. The cytoskeletal protein Flightless I (Flii) is a known regulator of both development and wound healing. Using Flii(+/-), WT and Flii(Tg/Tg) mice, we investigated the effect of altering Flii levels in embryos and adult mice on the development of the epidermal barrier and, consequently, how this affects the integrity of the skin in EB. Flii over-expression resulted in delayed formation of the epidermal barrier in embryos and decreased expression of tight junction (TJ) proteins Claudin-1 and ZO-2. Increased intercellular space and transepidermal water loss was observed in Flii(Tg)(/Tg) adult mouse skin, while Flii(Tg/Tg) keratinocytes showed altered TJ protein localization and reduced transepithelial resistance. Flii is increased in the blistered skin of patients with EB, and over-expression of Flii in experimental EBA showed impaired Claudin-1 and -4 TJ protein expression and delayed recovery of functional barrier post-blistering. Immunoprecipitation confirmed Flii associated with TJ proteins and in vivo actin assays showed that the effect of Flii on actin polymerization underpinned the impaired barrier function observed in Flii(Tg/Tg) mice. These results therefore demonstrate an important role for Flii in the development and regulation of the epidermal barrier, which may contribute to the impaired healing and skin fragility of EB patients.
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Affiliation(s)
- Zlatko Kopecki
- Centre for Regenerative Medicine, Mawson Institute, University of South Australia, Adelaide, Australia; Women's and Children's Health Research Institute, Adelaide, Australia
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184
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Proton-sensitive cation channels and ion exchangers in ischemic brain injury: new therapeutic targets for stroke? Prog Neurobiol 2014; 115:189-209. [PMID: 24467911 DOI: 10.1016/j.pneurobio.2013.12.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/28/2013] [Accepted: 12/24/2013] [Indexed: 12/13/2022]
Abstract
Ischemic brain injury results from complicated cellular mechanisms. The present therapy for acute ischemic stroke is limited to thrombolysis with the recombinant tissue plasminogen activator (rtPA) and mechanical recanalization. Therefore, a better understanding of ischemic brain injury is needed for the development of more effective therapies. Disruption of ionic homeostasis plays an important role in cell death following cerebral ischemia. Glutamate receptor-mediated ionic imbalance and neurotoxicity have been well established in cerebral ischemia after stroke. However, non-NMDA receptor-dependent mechanisms, involving acid-sensing ion channel 1a (ASIC1a), transient receptor potential melastatin 7 (TRPM7), and Na(+)/H(+) exchanger isoform 1 (NHE1), have recently emerged as important players in the dysregulation of ionic homeostasis in the CNS under ischemic conditions. These H(+)-sensitive channels and/or exchangers are expressed in the majority of cell types of the neurovascular unit. Sustained activation of these proteins causes excessive influx of cations, such as Ca(2+), Na(+), and Zn(2+), and leads to ischemic reperfusion brain injury. In this review, we summarize recent pre-clinical experimental research findings on how these channels/exchangers are regulated in both in vitro and in vivo models of cerebral ischemia. The blockade or transgenic knockdown of these proteins was shown to be neuroprotective in these ischemia models. Taken together, these non-NMDA receptor-dependent mechanisms may serve as novel therapeutic targets for stroke intervention.
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185
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Tominaga M, Takamori K. Recent advances in pathophysiological mechanisms of itch. ACTA ACUST UNITED AC 2014. [DOI: 10.1586/edm.10.7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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186
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MyD88 adaptor-like (Mal) functions in the epithelial barrier and contributes to intestinal integrity via protein kinase C. Mucosal Immunol 2014; 7:57-67. [PMID: 23612054 DOI: 10.1038/mi.2013.24] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 03/19/2013] [Indexed: 02/07/2023]
Abstract
MyD88 adapter-like (Mal)-deficient mice displayed increased susceptibility to oral but not intraperitoneal infection with Salmonella Typhimurium. Bone marrow chimeras demonstrated that mice with Mal-deficient non-hematopoietic cells were more susceptible to infection, indicating a role for Mal in non-myeloid cells. We observed perturbed barrier function in Mal(-/-) mice, as indicated by reduced electrical resistance and increased mucosa blood permeability following infection. Altered expression of occludin, Zonula occludens-1, and claudin-3 in intestinal epithelia from Mal(-/-) mice suggest that Mal regulates tight junction formation, which may in part contribute to intestinal integrity. Mal interacted with several protein kinase C (PKC) isoforms in a Caco-2 model of intestinal epithelia and inhibition of Mal or PKC increased permeability and bacterial invasion via a paracellular route, while a pan-PKC inhibitor increased susceptibility to oral infection in mice. Mal signaling is therefore beneficial to the integrity of the intestinal barrier during infection.
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187
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Nagaraja TN, Aryal MP, Brown SL, Bagher-Ebadian H, Mikkelsen T, Yang JJ, Panda S, Keenan KA, Cabral G, Ewing JR. Cilengitide-induced temporal variations in transvascular transfer parameters of tumor vasculature in a rat glioma model: identifying potential MRI biomarkers of acute effects. PLoS One 2013; 8:e84493. [PMID: 24376814 PMCID: PMC3871527 DOI: 10.1371/journal.pone.0084493] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/14/2013] [Indexed: 11/30/2022] Open
Abstract
Increased efficacy of radiotherapy (RT) 4-8 h after Cilengitide treatment has been reported. We hypothesized that the effects of Cilengitide on tumor transvascular transfer parameters might underlie, and thus predict, this potentiation. Athymic rats with orthotopic U251 glioma were studied at ~21 days after implantation using dynamic contrast-enhanced (DCE)-MRI. Vascular parameters, viz: plasma volume fraction (vp), forward volume transfer constant (Ktrans) and interstitial volume fraction (ve) of a contrast agent, were determined in tumor vasculature once before, and again in cohorts 2, 4, 8, 12 and 24 h after Cilengitide administration (4 mg/kg; N = 31; 6-7 per cohort). Perfusion-fixed brain sections were stained for von Willebrand factor to visualize vascular segments. A comparison of pre- and post-treatment parameters showed that the differences between MR indices before and after Cilengitide treatment pivoted around the 8 h time point, with 2 and 4 h groups showing increases, 12 and 24 h groups showing decreases, and values at the 8 h time point close to the baseline. The vascular parameter differences between group of 2 and 4 h and group of 12 and 24 h were significant for Ktrans (p = 0.0001 and ve (p = 0,0271). Vascular staining showed little variation with time after Cilengitide. The vascular normalization occurring 8 h after Cilengitide treatment coincided with similar previous reports of increased treatment efficacy when RT followed Cilengitide by 8 h. Pharmacological normalization of vasculature has the potential to increase sensitivity to RT. Evaluating acute temporal responses of tumor vasculature to putative anti-angiogenic drugs may help in optimizing their combination with other treatment modalities.
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Affiliation(s)
- Tavarekere N. Nagaraja
- Department of Anesthesiology, Henry Ford Hospital, Detroit, Michigan, United States of America
- * E-mail:
| | - Madhava P. Aryal
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
- Department of Physics, Oakland University, Rochester, Michigan, United States of America
| | - Stephen L. Brown
- Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Hassan Bagher-Ebadian
- Department of Diagnostic Radiology, Henry Ford Hospital, Detroit, Michigan, United States of America
- Department of Physics, Oakland University, Rochester, Michigan, United States of America
| | - Tom Mikkelsen
- Department of Neurosurgery, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - James J. Yang
- Public Health Sciences, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Swayamprava Panda
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Kelly A. Keenan
- Department of Anesthesiology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - Glauber Cabral
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
| | - James R. Ewing
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan, United States of America
- Department of Physics, Oakland University, Rochester, Michigan, United States of America
- Department of Neurology, Wayne State University, Detroit, Michigan, United States of America
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Zehendner CM, Librizzi L, Hedrich J, Bauer NM, Angamo EA, de Curtis M, Luhmann HJ. Moderate hypoxia followed by reoxygenation results in blood-brain barrier breakdown via oxidative stress-dependent tight-junction protein disruption. PLoS One 2013; 8:e82823. [PMID: 24324834 PMCID: PMC3855783 DOI: 10.1371/journal.pone.0082823] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 10/28/2013] [Indexed: 11/19/2022] Open
Abstract
Re-canalization of cerebral vessels in ischemic stroke is pivotal to rescue dysfunctional brain areas that are exposed to moderate hypoxia within the penumbra from irreversible cell death. Goal of the present study was to evaluate the effect of moderate hypoxia followed by reoxygenation (MHR) on the evolution of reactive oxygen species (ROS) and blood-brain barrier (BBB) integrity in brain endothelial cells (BEC). BBB integrity was assessed in BEC in vitro and in microvessels of the guinea pig whole brain in situ preparation. Probes were exposed to MHR (2 hours 67-70 mmHg O2, 3 hours reoxygenation, BEC) or towards occlusion of the arteria cerebri media (MCAO) with or without subsequent reperfusion in the whole brain preparation. In vitro BBB integrity was evaluated using trans-endothelial electrical resistance (TEER) and transwell permeability assays. ROS in BEC were evaluated using 2',7'-dichlorodihydrofluorescein diacetate (DCF), MitoSox and immunostaining for nitrotyrosine. Tight-junction protein (TJ) integrity in BEC, stainings for nitrotyrosine and FITC-albumin extravasation in the guinea pig brain preparation were assessed by confocal microscopy. Diphenyleneiodonium (DPI) was used to investigate NADPH oxidase dependent ROS evolution and its effect on BBB parameters in BEC. MHR impaired TJ proteins zonula occludens 1 (ZO-1) and claudin 5 (Cl5), decreased TEER, and significantly increased cytosolic ROS in BEC. These events were blocked by the NADPH oxidase inhibitor DPI. MCAO with or without subsequent reoxygenation resulted in extravasation of FITC-albumin and ROS generation in the penumbra region of the guinea pig brain preparation and confirmed BBB damage. BEC integrity may be impaired through ROS in MHR on the level of TJ and the BBB is also functionally impaired in moderate hypoxic conditions followed by reperfusion in a complex guinea pig brain preparation. These findings suggest that the BBB is susceptible towards MHR and that ROS play a key role in this process.
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Affiliation(s)
- Christoph M. Zehendner
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
- * E-mail:
| | - Laura Librizzi
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy
| | - Jana Hedrich
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Nina M. Bauer
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Eskedar A. Angamo
- Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Marco de Curtis
- Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, Milano, Italy
| | - Heiko J. Luhmann
- Institute of Physiology and Pathophysiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
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189
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Resolvin D1 reverts lipopolysaccharide-induced TJ proteins disruption and the increase of cellular permeability by regulating IκBα signaling in human vascular endothelial cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:185715. [PMID: 24381712 PMCID: PMC3870867 DOI: 10.1155/2013/185715] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 09/29/2013] [Accepted: 09/30/2013] [Indexed: 12/02/2022]
Abstract
Tight Junctions (TJ) are important components of paracellular pathways, and their destruction enhances vascular permeability. Resolvin D1 (RvD1) is a novel lipid mediator that has treatment effects on inflammatory diseases, but its effect on inflammation induced increase in vascular permeability is unclear. To understand whether RvD1 counteracts the lipopolysaccharide (LPS) induced increase in vascular cell permeability, we investigated the effects of RvD1 on endothelial barrier permeability and tight junction reorganization and expression in the presence or absence of LPS stimulation in cultured Human Vascular Endothelial Cells (HUVECs). Our results showed that RvD1 decreased LPS-induced increased in cellular permeability and inhibited the LPS-induced redistribution of zo-1, occludin, and F-actin in HUVECs. Moreover, RvD1 attenuated the expression of IκBα in LPS-induced HUVECs. The NF-κB inhibitor PDTC enhanced the protective effects of RvD1 on restoration of occludin rather than zo-1 expression in LPS-stimulated HUVECs. By contrast, the ERK1/2 inhibitor PD98059 had no effect on LPS-induced alterations in zo-1 and occludin protein expressions in HUVECs. Our data indicate that RvD1 protects against impairment of endothelial barrier function induced by LPS through upregulating the expression of TJ proteins in HUVECs, which involves the IκBα pathway but not the ERK1/2 signaling.
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190
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Lee SR, Wang X, Tsuji K, Lo EH. Extracellular proteolytic pathophysiology in the neurovascular unit after stroke. Neurol Res 2013; 26:854-61. [PMID: 15727269 DOI: 10.1179/016164104x3806] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The NINDS Stroke Progress Review Group recommended a shift in emphasis from a purely neurocentric view of cell death towards a more integrative approach whereby responses in all brain cells and matrix are considered. The neurovascular unit (fundamentally comprising endothelium, astrocyte, and neuron) provides a conceptual framework where cell-cell and cell-matrix signaling underlies the overall tissue response to stroke and its treatments. Here, we briefly review recent data on extracellular proteolytic dysfunction in the neurovascular unit after a stroke. The breakdown of neurovascular matrix initiates blood-brain barrier disruption with edema and/or hemorrhage. Endothelial dysfunction amplifies inflammatory responses. Perturbation of cell-matrix homeostasis triggers multiple cell death pathways. Interactions between the major classes of extracellular proteases from the plasminogen and matrix metalloprotease families may underlie processes responsible for some of the hemorrhagic complications of thrombolytic stroke therapy. Targeting the proteolytic imbalance within the neurovascular unit may provide new approaches for improving the safety and efficacy of thrombolytic reperfusion therapy for stroke.
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Affiliation(s)
- Sun-Ryung Lee
- Neuroprotection Research Laboratory, Department of Radiology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, MA 02129, USA
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191
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Panazzolo DG, Silva LHAD, Cyrino FZGDA, Sicuro FL, Kraemer-Aguiar LG, Bouskela E. Gender differences in microcirculation: observation using the hamster cheek pouch. Clinics (Sao Paulo) 2013; 68:1537-42. [PMID: 24473512 PMCID: PMC3840373 DOI: 10.6061/clinics/2013(12)10] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/15/2013] [Indexed: 01/30/2023] Open
Abstract
OBJECTIVES Estrogen has been shown to play an important protective role in non-reproductive systems, such as the cardiovascular system. Our aim was to observe gender differences in vivo with regard to the increase in macromolecular permeability and leukocyte-endothelium interaction induced by ischemia/reperfusion as well as in microvascular reactivity to vasoactive substances using the hamster cheek pouch preparation. METHODS Thirty-six male and 36 female hamsters, 21 weeks old, were selected for this study, and their cheek pouches were prepared for intravital microscopy. An increase in the macromolecular permeability of post-capillary venules was quantified as a leakage of intravenously injected fluorescein-labeled dextran, and the leukocyte-endothelium interaction was measured as the number of fluorescent rolling leukocytes or leukocytes adherent to the venular wall, labeled with rhodamin G, during reperfusion after 30 min of local ischemia. For microvascular reactivity, the mean internal diameter of arterioles was evaluated after the topical application of different concentrations of two vasoconstrictors, phenylephrine (α1-agonist) and endothelin-1, and two vasodilators, acetylcholine (endothelial-dependent) and sodium nitroprusside (endothelial-independent). RESULTS The increase in macromolecular permeability induced by ischemia/reperfusion was significantly lower in females compared with males [19 (17-22) leaks/cm2 vs. 124 (123-128) leaks/cm2, respectively, p<0.001), but the number of rolling or adherent leukocytes was not different between the groups. Phenylephrine-induced arteriolar constriction was significantly lower in females compared with males [77 (73-102)% vs. 64 (55-69)%, p<0.04], but there were no detectable differences in endothelin-1-dependent vasoreactivity. Additionally, arteriolar vasodilatation elicited by acetylcholine or sodium nitroprusside did not differ between the groups. CONCLUSION The female gender could have a direct protective role in microvascular reactivity and the increase in macromolecular permeability induced by ischemia/reperfusion.
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Affiliation(s)
- Diogo Guarnieri Panazzolo
- Clinical and Experimental Research Laboratory on Vascular Biology, Biomedical Center, State University of Rio de Janeiro, Rio de JaneiroRJ, Brazil
| | - Lucia Henriques Alves da Silva
- Clinical and Experimental Research Laboratory on Vascular Biology, Biomedical Center, State University of Rio de Janeiro, Rio de JaneiroRJ, Brazil
| | - Fátima Zely Garcia de Almeida Cyrino
- Clinical and Experimental Research Laboratory on Vascular Biology, Biomedical Center, State University of Rio de Janeiro, Rio de JaneiroRJ, Brazil
| | - Fernando Lencastre Sicuro
- Clinical and Experimental Research Laboratory on Vascular Biology, Biomedical Center, State University of Rio de Janeiro, Rio de JaneiroRJ, Brazil
| | - Luiz Guilherme Kraemer-Aguiar
- Clinical and Experimental Research Laboratory on Vascular Biology, Biomedical Center, State University of Rio de Janeiro, Rio de JaneiroRJ, Brazil
| | - Eliete Bouskela
- Clinical and Experimental Research Laboratory on Vascular Biology, Biomedical Center, State University of Rio de Janeiro, Rio de JaneiroRJ, Brazil
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192
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Peng H, Luo P, Li Y, Wang C, Liu X, Ye Z, Li C, Lou T. Simvastatin alleviates hyperpermeability of glomerular endothelial cells in early-stage diabetic nephropathy by inhibition of RhoA/ROCK1. PLoS One 2013; 8:e80009. [PMID: 24244596 PMCID: PMC3828237 DOI: 10.1371/journal.pone.0080009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/04/2013] [Indexed: 02/03/2023] Open
Abstract
Background Endothelial dysfunction is an early sign of diabetic cardiovascular disease and may contribute to progressive diabetic nephropathy (DN). There is increasing evidence that dysfunction of the endothelial tight junction is a crucial step in the development of endothelial hyperpermeability, but it is unknown whether this occurs in glomerular endothelial cells (GEnCs) during the progression of DN. We examined tight junction dysfunction of GEnCs during early-stage DN and the potential underlying mechanisms. We also examined the effect of simvastatin (3-Hydroxy-3-methylglutaryl CoA reductase inhibitor) on dysfunction of the tight junctions of cultured GEnCs and in db/db mice with early-stage DN. Methods We assessed the expression of occludin and ZO-1, two major components of the tight junction complex, in cultured rat GEnCs treated with high glucose and in 12 week-old db/db mice with early-stage DN. We also investigated activation of RhoA/ROCK1 signaling, GEnC permeability, and renal function of the mice. Results High glucose suppresses occludin expression and disrupts occludin/ZO-1 translocation in GEnCs. These changes were associated with increased permeability to albumin and activation of RhoA/ROCK1 signaling. Occludin and ZO-1 dysregulation also occurred in the glomeruli of mice with early-stage DN, and these abnormalities were accompanied by albuminuria and activation of RhoA/ROCK1 in isolated glomeruli. Simvastatin prevented high glucose or hyperglycemia-induced dysregulation of occludin and ZO-1 by inhibition of RhoA/ROCK1 signaling in cultured GEnCs and in db/db mice with early-stage DN. Conclusion Our results indicate that activation of RhoA/ROCK1 by high glucose disrupts the expression and translocation of occludin/ZO-1 and that simvastatin alleviates occludin/ZO-1 dysregulation and albuminuria by suppressing RhoA/ROCK1 signaling during early-stage DN. These results suggest a potential therapeutic strategy for preventing the onset of albuminuria in early-stage DN.
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Affiliation(s)
- Hui Peng
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Pengli Luo
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Yuanqing Li
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Cheng Wang
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Xun Liu
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Zengchun Ye
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Canming Li
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
| | - Tanqi Lou
- Division of Nephrology, Department of Internal Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, P. R. China
- * E-mail:
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193
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Cura AJ, Carruthers A. Role of monosaccharide transport proteins in carbohydrate assimilation, distribution, metabolism, and homeostasis. Compr Physiol 2013; 2:863-914. [PMID: 22943001 DOI: 10.1002/cphy.c110024] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The facilitated diffusion of glucose, galactose, fructose, urate, myoinositol, and dehydroascorbicacid in mammals is catalyzed by a family of 14 monosaccharide transport proteins called GLUTs. These transporters may be divided into three classes according to sequence similarity and function/substrate specificity. GLUT1 appears to be highly expressed in glycolytically active cells and has been coopted in vitamin C auxotrophs to maintain the redox state of the blood through transport of dehydroascorbate. Several GLUTs are definitive glucose/galactose transporters, GLUT2 and GLUT5 are physiologically important fructose transporters, GLUT9 appears to be a urate transporter while GLUT13 is a proton/myoinositol cotransporter. The physiologic substrates of some GLUTs remain to be established. The GLUTs are expressed in a tissue specific manner where affinity, specificity, and capacity for substrate transport are paramount for tissue function. Although great strides have been made in characterizing GLUT-catalyzed monosaccharide transport and mapping GLUT membrane topography and determinants of substrate specificity, a unifying model for GLUT structure and function remains elusive. The GLUTs play a major role in carbohydrate homeostasis and the redistribution of sugar-derived carbons among the various organ systems. This is accomplished through a multiplicity of GLUT-dependent glucose sensing and effector mechanisms that regulate monosaccharide ingestion, absorption,distribution, cellular transport and metabolism, and recovery/retention. Glucose transport and metabolism have coevolved in mammals to support cerebral glucose utilization.
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Affiliation(s)
- Anthony J Cura
- Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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194
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Alvarez JI, Katayama T, Prat A. Glial influence on the blood brain barrier. Glia 2013; 61:1939-58. [PMID: 24123158 PMCID: PMC4068281 DOI: 10.1002/glia.22575] [Citation(s) in RCA: 411] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/13/2013] [Accepted: 08/19/2013] [Indexed: 12/14/2022]
Abstract
The Blood Brain Barrier (BBB) is a specialized vascular structure tightly regulating central nervous system (CNS) homeostasis. Endothelial cells are the central component of the BBB and control of their barrier phenotype resides on astrocytes and pericytes. Interactions between these cells and the endothelium promote and maintain many of the physiological and metabolic characteristics that are unique to the BBB. In this review we describe recent findings related to the involvement of astroglial cells, including radial glial cells, in the induction of barrier properties during embryogenesis and adulthood. In addition, we describe changes that occur in astrocytes and endothelial cells during injury and inflammation with a particular emphasis on alterations of the BBB phenotype. GLIA 2013;61:1939–1958
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Affiliation(s)
- Jorge Ivan Alvarez
- Neuroimmunology unit, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
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195
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Park M, Kim HJ, Lim B, Wylegala A, Toborek M. Methamphetamine-induced occludin endocytosis is mediated by the Arp2/3 complex-regulated actin rearrangement. J Biol Chem 2013; 288:33324-34. [PMID: 24081143 PMCID: PMC3829179 DOI: 10.1074/jbc.m113.483487] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Methamphetamine (METH) is a drug of abuse with neurotoxic and neuroinflammatory effects, which include disruption of the blood-brain barrier (BBB) and alterations of tight junction protein expression. This study focused on the actin cytoskeletal rearrangement as a modulator of METH-induced redistribution of tight junction protein occludin in brain endothelial cells. Exposure to METH resulted in a shift of occludin localization from plasma membranes to endosomes. These changes were accompanied by activation of the actin-related protein 2/3 (Arp2/3) complex, which stimulates actin polymerization by promoting actin nucleation. In addition, METH-induced coronin-1b phosphorylation diminishes the inhibitory effect of nonphosphorylated coronin-1b on actin nucleation. Blocking actin nucleation with CK-666, a specific inhibitor of the Arp2/3 complex, protected against METH-induced occludin internalization and increased transendothelial monocyte migration. Importantly, treatment with CK-666 attenuated a decrease in occludin levels in brain microvessels and BBB permeability of METH-injected mice. These findings indicate that actin cytoskeletal dynamics is detrimental to METH-induced BBB dysfunction by increasing internalization of occludin.
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Affiliation(s)
- Minseon Park
- From the Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136 and
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196
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Hu YJ, Wang YD, Tan FQ, Yang WX. Regulation of paracellular permeability: factors and mechanisms. Mol Biol Rep 2013; 40:6123-42. [PMID: 24062072 DOI: 10.1007/s11033-013-2724-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Accepted: 09/14/2013] [Indexed: 12/20/2022]
Abstract
Epithelial permeability is composed of transcellular permeability and paracellular permeability. Paracellular permeability is controlled by tight junctions (TJs). Claudins and occludin are two major transmembrane proteins in TJs, which directly determine the paracellular permeability to different ions or large molecules. Intracellular signaling pathways including Rho/Rho-associated protein kinase, protein kinase Cs, and mitogen-activated protein kinase, modulate the TJ proteins to affect paracellular permeability in response for diverse stimuli. Cytokines, growth factors and hormones in organism can regulate the paracellular permeability via signaling pathway. The transcellular transporters such as Na-K-ATPase, Na(+)-coupled transporters and chloride channels, can interact with paracellular transport and regulate the TJs. In this review, we summarized the factors affecting paracellular permeability and new progressions of the related mechanism in recent studies, and pointed out further research areas.
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Affiliation(s)
- Yan-Jun Hu
- Department of Reproductive Endocrinology, Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, 310006, People's Republic of China
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197
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Rodriguez PL, Jiang S, Fu Y, Avraham S, Avraham HK. The proinflammatory peptide substance P promotes blood-brain barrier breaching by breast cancer cells through changes in microvascular endothelial cell tight junctions. Int J Cancer 2013; 134:1034-44. [PMID: 23934616 DOI: 10.1002/ijc.28433] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/30/2013] [Indexed: 01/28/2023]
Abstract
Neuropeptide substance P (SP) has been implicated in inflammation, pain, depression and breast cancer cell (BCC) growth. Here, we examined the role of SP in trafficking of BCCs (human MDA-MB-231 and MDA-MB-231BrM2 cells) across the blood-brain barrier (BBB) and brain microvascular endothelial cells (BMECs) using in vitro and in vivo models. SP was secreted from BCCs and mediated adhesion and transmigration of BCCs across human BMECs (HBMECs) in vitro. SP induced activation of HBMECs, leading to secretion of Tumor Necrosis Factor alpha (TNF-α) and angiopoietin-2 (Ang-2) from HBMECs, resulting in changes in localization and distribution of tight junction (TJ) ZO-1 (tight junction protein zonula occludins-1) and claudin-5 structures as well as increased permeability of HBMECs. Using spontaneous breast cancer metastasis mouse model (syngeneic) of GFP-4T1-BrM5 mammary tumor cells administered into mammary fat pads of Balb/c mice, SP inhibitor spantide III inhibited in vivo changes in permeability of the BBB and BMEC-TJs ZO-1 and claudin-5 structures as well as decreased tumor cell colonization in brain. Thus, SP secreted from BCCs induces transmigration of BCCs across the BBB, leading to activation of BMECs and secretion of TNF-α and Ang-2, resulting in BBB impairment and colonization of tumor cells in brain. Therefore, therapies based on SP inhibition in combination with other therapies may prevent breaching of the BBB by BCCs and their colonization in brain.
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Affiliation(s)
- Pedro L Rodriguez
- The Division of Experimental Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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198
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Microvascular complications and diabetic retinopathy: recent advances and future implications. Future Med Chem 2013; 5:301-14. [PMID: 23464520 DOI: 10.4155/fmc.12.206] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Retinal microvascular alterations have been observed during diabetic retinopathy (DR) due to the retinal susceptibility towards subtle pathological alterations. Therefore, retinal microvascular pathology is essential to understand the nature of retinal degenerations during DR. In this review, the role of retinal microvasculature complications during progression of DR, along with recent efforts to normalize such alterations for better therapeutic outcome, will be underlined. In addition, current therapeutics and future directions for advancement of standard treatment for DR patients will be discussed.
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199
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Maeng YS, Maharjan S, Kim JH, Park JH, Suk Yu Y, Kim YM, Kwon YG. Rk1, a ginsenoside, is a new blocker of vascular leakage acting through actin structure remodeling. PLoS One 2013; 8:e68659. [PMID: 23894330 PMCID: PMC3718811 DOI: 10.1371/journal.pone.0068659] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 06/03/2013] [Indexed: 12/29/2022] Open
Abstract
Endothelial barrier integrity is essential for vascular homeostasis and increased vascular permeability and has been implicated in many pathological processes, including diabetic retinopathy. Here, we investigated the effect of Rk1, a ginsenoside extracted from sun ginseng, on regulation of endothelial barrier function. In human retinal endothelial cells, Rk1 strongly inhibited permeability induced by VEGF, advanced glycation end-product, thrombin, or histamine. Furthermore, Rk1 significantly reduced the vessel leakiness of retina in a diabetic mouse model. This anti-permeability activity of Rk1 is correlated with enhanced stability and positioning of tight junction proteins at the boundary between cells. Signaling experiments revealed that Rk1 induces phosphorylation of myosin light chain and cortactin, which are critical regulators for the formation of the cortical actin ring structure and endothelial barrier. These findings raise the possibility that ginsenoside Rk1 could be exploited as a novel prototype compound for the prevention of human diseases that are characterized by vascular leakage.
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Affiliation(s)
- Yong-Sun Maeng
- Department of Biochemistry College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
- Corneal Dystrophy Research Institute and Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Sony Maharjan
- Department of Biochemistry College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Jeong-Hun Kim
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jeong-Hill Park
- Research Institute of Pharmaceutical Science, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Young Suk Yu
- Department of Ophthalmology, College of Medicine, Seoul National University, Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Young-Myoung Kim
- Vascular System Research Center, Kangwon National University, Kangwon-Do, Republic of Korea
| | - Young-Guen Kwon
- Department of Biochemistry College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
- * E-mail:
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200
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Wang H, Bastian SEP, Howarth GS. Newly Developed Synbiotics and the Chemotherapy-Damaged Gut. J Evid Based Complementary Altern Med 2013; 18:198-208. [DOI: 10.1177/2156587213477864] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2025] Open
Abstract
Mucositis is a common side-effect of cancer chemotherapy and radiotherapy. Features of mucositis include erythema, ulceration, and inflammation of the gastrointestinal tract accompanied by clinical symptoms of abdominal pain and digestive disturbances. New treatment strategies are required. Experimental evidence is accumulating showing therapeutic promise for new nutraceutical agents including probiotic bacteria, probiotic-derived factors, prebiotics, and plant extracts. However, the targeted development of new combinations of these agents (synbiotics) to combat mucositis remains largely unexplored. The current review addresses the potential for these nutraceutical agents to reduce the severity of chemotherapy-damaged mucositis by strategically aligning their underlying mechanism of action with features of mucositis pathogenesis. The potential for certain plant extracts to act as prebiotics, in combination with probiotics or their derived factors, is further investigated. These unique synbiotic formulations could form the basis of a new naturally sourced adjunctive approach to cancer chemotherapy.
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Affiliation(s)
- Hanru Wang
- School of Animal and Veterinary Sciences; University of Adelaide, Roseworthy Campus, South Australia, Australia
| | - Susan E. P. Bastian
- School of Agriculture, Food and Wine; University of Adelaide, Waite Campus, South Australia, Australia
| | - Gordon S. Howarth
- School of Animal and Veterinary Sciences; University of Adelaide, Roseworthy Campus, South Australia, Australia
- Centre for Paediatric and Adolescent Gastroenterology, Children, Youth and Women’s Health Service, North Adelaide, South Australia, Australia
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