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Paldino E, Migliorato G, Fusco FR. Neuroimmune pathways involvement in neurodegeneration of R6/2 mouse model of Huntington's disease. Front Cell Neurosci 2024; 18:1360066. [PMID: 38444595 PMCID: PMC10912295 DOI: 10.3389/fncel.2024.1360066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 01/23/2024] [Indexed: 03/07/2024] Open
Abstract
Mechanisms of tissue damage in Huntington's disease (HD) involve excitotoxicity, mitochondrial damage, and neuroinflammation, including microglia activation. CD47 is a membrane protein that interacts with the inhibitory immunoreceptor SIRPα. Engagement of SIRPα by CD47 provides a downregulatory signal that inhibits host cell phagocytosis, promoting a "don't-eat-me" signal. These proteins are involved in the immune response and are downmodulated in inflammatory diseases. The involvement of inflammation and of the inflammasome in HD has already been described. In this study, we focused on other factors that can be involved in the unregulated inflammatory response that accelerates and exacerbate the neurodegenerative process in HD. Our results show that CD47 on striatal neurons decreased in HD mice, while it increased in wild type mice with age. SIRPα, on the other hand, was present in neurons in the wild type and increases in the R6/2 mice at all stages. Recruitment of SIRPα and binding to CD47 promotes the activation through phosphorylating events of non-receptor protein tyrosine phosphatase SHP-1 and SHP-2 in neurons and microglia. SHP phosphatases are able to curb the activity of NLRP3 inflammasome thereby reducing the detrimental effect of neuroinflammation. Such activity is mediated by the inhibition (dephosphorylation) of the proteins signal transducer and activator of transcription (STAT). We found that activated SHP-1 was present in microglia and neurons of WT mice at 5 and 13 weeks, increasing with time; while in R6/2 it was not localized in neurons but only in microglia, where it decreases with time. Consequently, STAT1 was overexpressed in neurons of R6/2 mice, as an effect of lack of modulation by SHP-1. Thus, our results shed light on the pathophysiology of neuronal damage, on one hand, paving the way toward a modulation of signal transducer proteins by specific inhibitors to achieve neuroprotection in HD, on the other.
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Affiliation(s)
- Emanuela Paldino
- Laboratory of Neuroanatomy, Fondazione Santa Lucia IRCCS, Rome, Italy
| | - Giorgia Migliorato
- Laboratory of Neuroanatomy, Fondazione Santa Lucia IRCCS, Rome, Italy
- Department of Life Sciences, University of Trieste, Trieste, Italy
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2
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Ghatak S, Khanna S, Roy S, Thirunavukkarasu M, Pradeep SR, Wulff BC, El Masry MS, Sharma A, Palakurti R, Ghosh N, Xuan Y, Wilgus TA, Maulik N, Yoder MC, Sen CK. Driving adult tissue repair via re-engagement of a pathway required for fetal healing. Mol Ther 2023; 31:454-470. [PMID: 36114673 PMCID: PMC9931555 DOI: 10.1016/j.ymthe.2022.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 08/16/2022] [Accepted: 09/06/2022] [Indexed: 02/07/2023] Open
Abstract
Fetal cutaneous wound closure and repair differ from that in adulthood. In this work, we identify an oxidant stress sensor protein, nonselenocysteine-containing phospholipid hydroperoxide glutathione peroxidase (NPGPx), that is abundantly expressed in normal fetal epidermis (and required for fetal wound closure), though not in adult epidermis, but is variably re-induced upon adult tissue wounding. NPGPx is a direct target of the miR-29 family. Following injury, abundance of miR-29 is lowered, permitting a prompt increase in NPGPx transcripts and protein expression in adult wound-edge tissue. NPGPx expression was required to mediate increased keratinocyte migration induced by miR-29 inhibition in vitro and in vivo. Increased NPGPx expression induced increased SOX2 expression and β-catenin nuclear localization in keratinocytes. Augmenting physiologic NPGPx expression via experimentally induced miR-29 suppression, using cutaneous tissue nanotransfection or targeted lipid nanoparticle delivery of anti-sense oligonucleotides, proved to be sufficient to overcome the deleterious effects of diabetes on this specific pathway to enhance tissue repair.
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Affiliation(s)
- Subhadip Ghatak
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Savita Khanna
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sashwati Roy
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Mahesh Thirunavukkarasu
- Department of Surgery, Molecular Cardiology and Angiogenesis Laboratory, University of Connecticut Health, Farmington, CT 06030, USA
| | - Seetur R Pradeep
- Department of Surgery, Molecular Cardiology and Angiogenesis Laboratory, University of Connecticut Health, Farmington, CT 06030, USA
| | - Brian C Wulff
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Mohamed S El Masry
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Plastic Surgery, Zagazig University, Zagazig 44519, Egypt
| | - Anu Sharma
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ravichand Palakurti
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Nandini Ghosh
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yi Xuan
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Traci A Wilgus
- Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Nilanjana Maulik
- Department of Surgery, Molecular Cardiology and Angiogenesis Laboratory, University of Connecticut Health, Farmington, CT 06030, USA
| | - Mervin C Yoder
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Chandan K Sen
- Indiana Center for Regenerative Medicine & Engineering, Indiana University Health Comprehensive Wound Center, Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
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3
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Palakurti R, Biswas N, Roy S, Gnyawali SC, Sinha M, Singh K, Ghatak S, Sen CK, Khanna S. Inducible miR-1224 silences cerebrovascular Serpine1 and restores blood flow to the stroke-affected site of the brain. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:276-292. [PMID: 36726407 PMCID: PMC9868883 DOI: 10.1016/j.omtn.2022.12.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 12/31/2022] [Indexed: 01/04/2023]
Abstract
The α-tocotrienol (TCT) form of natural vitamin E is more potent than the better known α-tocopherol against stroke. Angiographic studies of canine stroke have revealed beneficial cerebrovascular effects of TCT. This work seeks to understand the molecular basis of such effect. In mice, TCT supplementation improved perfusion at the stroke-affected site by inducing miR-1224. miRNA profiling of a laser-capture-microdissected stroke-affected brain site identified miR-1224 as the only vascular miR induced. Lentiviral knockdown of miR-1224 significantly blunted the otherwise beneficial effects of TCT on stroke outcomes. Studies on primary brain microvascular endothelial cells revealed direct angiogenic properties of miR-1224. In mice not treated with TCT, advance stereotaxic delivery of an miR-1224 mimic to the stroke site markedly improved stroke outcomes. Mechanistic studies identified Serpine1 as a target of miR-1224. Downregulation of Serpine1 augmented the angiogenic response of the miR-1224 mimic in the brain endothelial cells. The inhibition of Serpine1, by dietary TCT and pharmacologically, increased cerebrovascular blood flow at the stroke-affected site and protected against stroke. This work assigns Serpine1, otherwise known to be of critical significance in stroke, a cerebrovascular function that worsens stroke outcomes. miR-1224-dependent inhibition of Serpine1 can be achieved by dietary TCT as well as by the small-molecule inhibitor TM5441.
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Affiliation(s)
- Ravichand Palakurti
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Nirupam Biswas
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sashwati Roy
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Surya C. Gnyawali
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Mithun Sinha
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Kanhaiya Singh
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Subhadip Ghatak
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Chandan K. Sen
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Savita Khanna
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA,Corresponding author: Savita Khanna, PhD, Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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Transcriptome profiles discriminate between Gram-positive and Gram-negative sepsis in preterm neonates. Pediatr Res 2022; 91:637-645. [PMID: 33767373 DOI: 10.1038/s41390-021-01444-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 01/20/2021] [Accepted: 02/17/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND Genome-wide expression profiles have been previously employed as clinical research diagnostic tools for newborn sepsis. We aimed to determine if transcriptomic profiles could discriminate between Gram-positive and Gram-negative bacterial sepsis in preterm infants. METHODS Prospective, observational, double-cohort study was conducted in very low birth weight infants with clinical signs and culture-positive sepsis. Blood samples were collected when clinical signs became apparent. Total RNA was processed for transcriptomic analysis. Results were validated by both reverse-transcription polymerase chain reaction and a mathematical model. RESULTS We included 25 septic preterm infants, 17 with Gram-positive and 8 with Gram-negative bacteria. The principal component analysis identified these two clusters of patients. We performed a predictive model based on 21 genes that showed an area under the receiver-operating characteristic curve of 1. Eight genes were overexpressed in Gram-positive septic infants: CD37, CSK, MAN2B2, MGAT1, MOB3A, MYO9B, SH2D3C, and TEP1. The most significantly overexpressed pathways were related to metabolic and immunomodulating responses that translated into an equilibrium between pro- and anti-inflammatory responses. CONCLUSIONS The transcriptomic profile allowed identification of whether the causative agent was Gram-positive or Gram-negative bacteria. The overexpression of genes such as CD37 and CSK, which control cytokine production and cell survival, could explain the better clinical outcome in sepsis caused by Gram-positive bacteria. IMPACT Transcriptomic profiles not only enable an early diagnosis of sepsis in very low birth weight infants but also discriminate between Gram-positive and Gram-negative bacteria as causative agents. The overexpression of some genes related to cytokine production and cell survival could explain the better clinical outcome in sepsis caused by Gram-positive bacteria, and could lead us to a future, targeted therapy.
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Meparishvili M, Chitadze L, Lagani V, McCabe B, Solomonia R. Src and Memory: A Study of Filial Imprinting and Predispositions in the Domestic Chick. Front Physiol 2021; 12:736999. [PMID: 34616310 PMCID: PMC8488273 DOI: 10.3389/fphys.2021.736999] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/20/2021] [Indexed: 11/13/2022] Open
Abstract
Visual imprinting is a learning process whereby young animals come to prefer a visual stimulus after exposure to it (training). The available evidence indicates that the intermediate medial mesopallium (IMM) in the domestic chick forebrain is a site of memory formation during visual imprinting. We have studied the role of Src, an important non-receptor tyrosine kinase, in memory formation. Amounts of total Src (Total-Src) and its two phosphorylated forms, tyrosine-416 (activated, 416P-Src) and tyrosine-527 (inhibited, 527P-Src), were measured 1 and 24 h after training in the IMM and in a control brain region, the posterior pole of nidopallium (PPN). One hour after training, in the left IMM, we observed a positive correlation between the amount of 527P-Src and learning strength that was attributable to learning, and there was also a positive correlation between 416P-Src and learning strength that was attributable to a predisposition to learn readily. Twenty-four hours after training, the amount of Total-Src increased with learning strength in both the left and right IMM, and amount of 527P-Src increased with learning strength only in the left IMM; both correlations were attributable to learning. A further, negative, correlation between learning strength and 416P-Src/Total-Src in the left IMM reflected a predisposition to learn. No learning-related changes were found in the PPN control region. We suggest that there are two pools of Src; one of them in an active state and reflecting a predisposition to learn, and the second one in an inhibited condition, which increases as a result of learning. These two pools may represent two or more signaling pathways, namely, one pathway downstream of Src activated by tyrosine-416 phosphorylation and another upstream of Src, keeping the enzyme in an inactivated state via phosphorylation of tyrosine-527.
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Affiliation(s)
- Maia Meparishvili
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Lela Chitadze
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Vincenzo Lagani
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia
| | - Brian McCabe
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Revaz Solomonia
- School of Natural Sciences and Medicine, Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia.,I. Beritashvili Centre of Experimental Biomedicine, Tbilisi, Georgia
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6
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Hamezah HS, Durani LW, Yanagisawa D, Ibrahim NF, Aizat WM, Makpol S, Wan Ngah WZ, Damanhuri HA, Tooyama I. Modulation of Proteome Profile in AβPP/PS1 Mice Hippocampus, Medial Prefrontal Cortex, and Striatum by Palm Oil Derived Tocotrienol-Rich Fraction. J Alzheimers Dis 2020; 72:229-246. [PMID: 31594216 PMCID: PMC6839455 DOI: 10.3233/jad-181171] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tocotrienol-rich fraction (TRF) is a mixture of vitamin E analogs derived from palm oil. We previously demonstrated that supplementation with TRF improved cognitive function and modulated amyloid pathology in AβPP/PS1 mice brains. The current study was designed to examine proteomic profiles underlying the therapeutic effect of TRF in the brain. Proteomic analyses were performed on samples of hippocampus, medial prefrontal cortex (mPFC), and striatum using liquid chromatography coupled to Q Exactive HF Orbitrap mass spectrometry. From these analyses, we profiled a total of 5,847 proteins of which 155 proteins were differentially expressed between AβPP/PS1 and wild-type mice. TRF supplementation of these mice altered the expression of 255 proteins in the hippocampus, mPFC, and striatum. TRF also negatively modulated the expression of amyloid beta A4 protein and receptor-type tyrosine-protein phosphatase alpha protein in the hippocampus. The expression of proteins in metabolic pathways, oxidative phosphorylation, and those involved in Alzheimer’s disease were altered in the brains of AβPP/PS1 mice that received TRF supplementation.
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Affiliation(s)
- Hamizah Shahirah Hamezah
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Japan
| | - Lina Wati Durani
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Japan
| | - Daijiro Yanagisawa
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Japan
| | - Nor Faeizah Ibrahim
- Department of Biochemistry, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia (UKM), Jalan Yaacob Latif, Cheras, Kuala Lumpur, Malaysia
| | - Wan Mohd Aizat
- Institute of Systems Biology, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
| | - Suzana Makpol
- Department of Biochemistry, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia (UKM), Jalan Yaacob Latif, Cheras, Kuala Lumpur, Malaysia
| | - Wan Zurinah Wan Ngah
- Department of Biochemistry, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia (UKM), Jalan Yaacob Latif, Cheras, Kuala Lumpur, Malaysia
| | - Hanafi Ahmad Damanhuri
- Department of Biochemistry, Faculty of Medicine, UKMMC, Universiti Kebangsaan Malaysia (UKM), Jalan Yaacob Latif, Cheras, Kuala Lumpur, Malaysia
| | - Ikuo Tooyama
- Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, Japan
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7
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Advani D, Gupta R, Tripathi R, Sharma S, Ambasta RK, Kumar P. Protective role of anticancer drugs in neurodegenerative disorders: A drug repurposing approach. Neurochem Int 2020; 140:104841. [PMID: 32853752 DOI: 10.1016/j.neuint.2020.104841] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/24/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022]
Abstract
The disease heterogeneity and little therapeutic progress in neurodegenerative diseases justify the need for novel and effective drug discovery approaches. Drug repurposing is an emerging approach that reinvigorates the classical drug discovery method by divulging new therapeutic uses of existing drugs. The common biological background and inverse tuning between cancer and neurodegeneration give weight to the conceptualization of repurposing of anticancer drugs as novel therapeutics. Many studies are available in the literature, which highlights the success story of anticancer drugs as repurposed therapeutics. Among them, kinase inhibitors, developed for various oncology indications evinced notable neuroprotective effects in neurodegenerative diseases. In this review, we shed light on the salient role of multiple protein kinases in neurodegenerative disorders. We also proposed a feasible explanation of the action of kinase inhibitors in neurodegenerative disorders with more attention towards neurodegenerative disorders. The problem of neurotoxicity associated with some anticancer drugs is also highlighted. Our review encourages further research to better encode the hidden potential of anticancer drugs with the aim of developing prospective repurposed drugs with no toxicity for neurodegenerative disorders.
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Affiliation(s)
- Dia Advani
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rohan Gupta
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rahul Tripathi
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Sudhanshu Sharma
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Rashmi K Ambasta
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India
| | - Pravir Kumar
- Department of Biotechnology, Molecular Neuroscience and Functional Genomics Laboratory, Room# FW4TF3, Mechanical Engineering Building, Shahbad Daulatpur, Bawana Road, Delhi, 110042, India.
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8
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Roy S, Sen CK, Ghatak S, Higuita-Castro N, Palakurti R, Nalluri N, Clark A, Stewart R, Gallego-Perez D, Prater DN, Khanna S. Neurogenic tissue nanotransfection in the management of cutaneous diabetic polyneuropathy. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2020; 28:102220. [PMID: 32422219 PMCID: PMC7802084 DOI: 10.1016/j.nano.2020.102220] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 04/01/2020] [Accepted: 04/27/2020] [Indexed: 01/26/2023]
Abstract
This work rests on our recent report on the successful use of tissue nanotransfection (TNT) delivery of Ascl1, Brn2, and Myt1l (TNTABM) to directly convert skin fibroblasts into electrophysiologically active induced neuronal cells (iN) in vivo. Here we report that in addition to successful neurogenic conversion of cells, TNTABM caused neurotrophic enrichment of the skin stroma. Thus, we asked whether such neurotrophic milieu of the skin can be leveraged to rescue pre-existing nerve fibers under chronic diabetic conditions. Topical cutaneous TNTABM caused elevation of endogenous NGF and other co-regulated neurotrophic factors such as Nt3. TNTABM spared loss of cutaneous PGP9.5+ mature nerve fibers in db/db diabetic mice. This is the first study demonstrating that under conditions of in vivo reprogramming, changes in the tissue microenvironment can be leveraged for therapeutic purposes such as the rescue of pre-existing nerve fibers from its predictable path of loss under conditions of diabetes.
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Affiliation(s)
- Sashwati Roy
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | - Chandan K Sen
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | - Subhadip Ghatak
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | | | - Ravichand Palakurti
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | - Nagajyothi Nalluri
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | - Andrew Clark
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | - Richard Stewart
- Department of Surgery, The Ohio State University, Columbus, OH
| | | | - Daniel N Prater
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN
| | - Savita Khanna
- Department of Surgery, Indiana Center for Regenerative Medicine and Engineering, Indiana University School of Medicine, Indianapolis, IN.
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9
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Choi YR, Kim JB, Kang SJ, Noh HR, Jou I, Joe EH, Park SM. The dual role of c-src in cell-to-cell transmission of α-synuclein. EMBO Rep 2020; 21:e48950. [PMID: 32372484 DOI: 10.15252/embr.201948950] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 04/02/2020] [Accepted: 04/14/2020] [Indexed: 12/12/2022] Open
Abstract
Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons located in the substantia nigra pars compacta and the presence of proteinaceous inclusions called Lewy bodies and Lewy neurites in numerous brain regions. Increasing evidence indicates that Lewy pathology progressively involves additional regions of the nervous system as the disease advances, and the prion-like propagation of α-synuclein (α-syn) pathology promotes PD progression. Accordingly, the modulation of α-syn transmission may be important for the development of disease-modifying therapies in patients with PD. Here, we demonstrate that α-syn fibrils induce c-src activation in neurons, which depends on the FcγRIIb-SHP-1/-2-c-src pathway and enhances signals for the uptake of α-syn into neurons. Blockade of c-src activation inhibits the uptake of α-syn and the formation of Lewy body-like inclusions. Furthermore, the blockade of c-src activation also inhibits the release of α-syn via activation of autophagy. The brain-permeable c-src inhibitor, saracatinib, efficiently reduces α-syn propagation into neighboring regions in an in vivo model system. These results suggest a new therapeutic target against progressive PD.
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Affiliation(s)
- Yu Ree Choi
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
| | - Jae-Bong Kim
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
| | - Seo-Jun Kang
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
| | - Hye Rin Noh
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
| | - Ilo Jou
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
| | - Eun-Hye Joe
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
| | - Sang Myun Park
- Department of Pharmacology, Ajou University School of Medicine, Suwon, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Korea.,Department of Biomedical Sciences, BK21 Plus Program, Ajou University School of Medicine, Suwon, Korea
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10
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Blockade of c-Src Within the Paraventricular Nucleus Attenuates Inflammatory Cytokines and Oxidative Stress in the Mechanism of the TLR4 Signal Pathway in Salt-Induced Hypertension. Neurosci Bull 2019; 36:385-395. [PMID: 31641986 DOI: 10.1007/s12264-019-00435-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 08/09/2019] [Indexed: 12/20/2022] Open
Abstract
Toll-like receptor 4 (TLR4) and cellular Src (c-Src) are closely associated with inflammatory cytokines and oxidative stress in hypertension, so we designed this study to explore the exact role of c-Src in the mechanism of action of the TLR4 signaling pathway in salt-induced hypertension. Salt-sensitive rats were given a high salt diet for 10 weeks to induce hypertension. This resulted in higher levels of TLR4, activated c-Src, pro-inflammatory cytokines, oxidative stress, and arterial pressure. Infusion of a TLR4 blocker into the hypothalamic paraventricular nucleus (PVN) decreased the activated c-Src, while microinjection of a c-Src inhibitor attenuated the PVN levels of nuclear factor-kappa B, pro-inflammatory cytokines, and oxidative stress. Our findings suggest that a long-term high-salt diet increases TLR4 expression in the PVN and this promotes the activation of c-Src, which upregulates the expression of pro-inflammatory cytokines and results in the overproduction of reactive oxygen species. Therefore, inhibiting central c-Src activity may be a new target for treating hypertension.
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11
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Gabrych DR, Lau VZ, Niwa S, Silverman MA. Going Too Far Is the Same as Falling Short †: Kinesin-3 Family Members in Hereditary Spastic Paraplegia. Front Cell Neurosci 2019; 13:419. [PMID: 31616253 PMCID: PMC6775250 DOI: 10.3389/fncel.2019.00419] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/02/2019] [Indexed: 01/18/2023] Open
Abstract
Proper intracellular trafficking is essential for neuronal development and function, and when any aspect of this process is dysregulated, the resulting "transportopathy" causes neurological disorders. Hereditary spastic paraplegias (HSPs) are a family of such diseases attributed to over 80 spastic gait genes (SPG), specifically characterized by lower extremity spasticity and weakness. Multiple genes in the trafficking pathway such as those relating to microtubule structure and function and organelle biogenesis are representative disease loci. Microtubule motor proteins, or kinesins, are also causal in HSP, specifically mutations in Kinesin-I/KIF5A (SPG10) and two kinesin-3 family members; KIF1A (SPG30) and KIF1C (SPG58). KIF1A is a motor enriched in neurons, and involved in the anterograde transport of a variety of vesicles that contribute to pre- and post-synaptic assembly, autophagic processes, and neuron survival. KIF1C is ubiquitously expressed and, in addition to anterograde cargo transport, also functions in retrograde transport between the Golgi and the endoplasmic reticulum. Only a handful of KIF1C cargos have been identified; however, many have crucial roles such as neuronal differentiation, outgrowth, plasticity and survival. HSP-related kinesin-3 mutants are characterized mainly as loss-of-function resulting in deficits in motility, regulation, and cargo binding. Gain-of-function mutants are also seen, and are characterized by increased microtubule-on rates and hypermotility. Both sets of mutations ultimately result in misdelivery of critical cargos within the neuron. This likely leads to deleterious cell biological cascades that likely underlie or contribute to HSP clinical pathology and ultimately, symptomology. Due to the paucity of histopathological or cell biological data assessing perturbations in cargo localization, it has been difficult to positively link these mutations to the outcomes seen in HSPs. Ultimately, the goal of this review is to encourage future academic and clinical efforts to focus on "transportopathies" through a cargo-centric lens.
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Affiliation(s)
- Dominik R Gabrych
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Victor Z Lau
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Shinsuke Niwa
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Michael A Silverman
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
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12
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Iida M, Sahashi K, Kondo N, Nakatsuji H, Tohnai G, Tsutsumi Y, Noda S, Murakami A, Onodera K, Okada Y, Nakatochi M, Tsukagoshi Okabe Y, Shimizu S, Mizuno M, Adachi H, Okano H, Sobue G, Katsuno M. Src inhibition attenuates polyglutamine-mediated neuromuscular degeneration in spinal and bulbar muscular atrophy. Nat Commun 2019; 10:4262. [PMID: 31537808 PMCID: PMC6753158 DOI: 10.1038/s41467-019-12282-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 08/29/2019] [Indexed: 12/12/2022] Open
Abstract
Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by an expanded CAG repeat in the androgen receptor (AR) gene. Here, we perform a comprehensive analysis of signaling pathways in a mouse model of SBMA (AR-97Q mice) utilizing a phosphoprotein assay. We measure the levels of 17 phosphorylated proteins in spinal cord and skeletal muscle of AR-97Q mice at three stages. The level of phosphorylated Src (p-Src) is markedly increased in the spinal cords and skeletal muscles of AR-97Q mice prior to the onset. Intraperitoneal administration of a Src kinase inhibitor improves the behavioral and histopathological phenotypes of the transgenic mice. We identify p130Cas as an effector molecule of Src and show that the phosphorylated p130Cas is elevated in murine and cellular models of SBMA. These results suggest that Src kinase inhibition is a potential therapy for SBMA.
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Affiliation(s)
- Madoka Iida
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
- Japan Society for the Promotion of Science, 5-3-1, Kojimachi, Chiyoda-ku, Tokyo, 102-0083, Japan
| | - Kentaro Sahashi
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
| | - Naohide Kondo
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
| | - Hideaki Nakatsuji
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
| | - Genki Tohnai
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
| | - Yutaka Tsutsumi
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
| | - Seiya Noda
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
- Department of Neurology, National Hospital Organization Suzuka National Hospital, 3-2-1, Kasado, Suzuka city, Mie, 513-8501, Japan
| | - Ayuka Murakami
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
- Department of Neurology, National Hospital Organization Suzuka National Hospital, 3-2-1, Kasado, Suzuka city, Mie, 513-8501, Japan
| | - Kazunari Onodera
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
- Department of Neurology, Aichi Medical University School of Medicine, 1, Karimata, Yazako, Nagakute-city, Aichi, 480-1195, Japan
| | - Yohei Okada
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
- Department of Neurology, Aichi Medical University School of Medicine, 1, Karimata, Yazako, Nagakute-city, Aichi, 480-1195, Japan
- Department of Physiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masahiro Nakatochi
- Department of Nursing, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya city, Aichi, 461-8673, Japan
| | - Yuka Tsukagoshi Okabe
- Department of Advanced Medicine, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8560, Japan
| | - Shinobu Shimizu
- Department of Advanced Medicine, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8560, Japan
| | - Masaaki Mizuno
- Department of Advanced Medicine, Nagoya University Hospital, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8560, Japan
| | - Hiroaki Adachi
- Department of Neurology, University of Occupational and Environmental Health School of Medicine, 1-1, Iseigaoka, Yahatanichi-ku, Kitakyushu-city, Fukuoka, 807-0804, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, 35, Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Gen Sobue
- Brain and Mind Research Center, Nagoya University, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya city, Aichi, 466-8550, Japan.
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13
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Hoque A, Williamson NA, Ameen SS, Ciccotosto GD, Hossain MI, Oakhill JS, Ng DCH, Ang CS, Cheng HC. Quantitative proteomic analyses of dynamic signalling events in cortical neurons undergoing excitotoxic cell death. Cell Death Dis 2019; 10:213. [PMID: 30824683 PMCID: PMC6397184 DOI: 10.1038/s41419-019-1445-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 01/20/2019] [Accepted: 02/01/2019] [Indexed: 12/23/2022]
Abstract
Excitotoxicity, caused by overstimulation or dysregulation of ionotropic glutamate receptors (iGluRs), is a pathological process directing neuronal death in many neurological disorders. The aberrantly stimulated iGluRs direct massive influx of calcium ions into the affected neurons, leading to changes in expression and phosphorylation of specific proteins to modulate their functions and direct their participation in the signalling pathways that induce excitotoxic neuronal death. To define these pathways, we used quantitative proteomic approaches to identify these neuronal proteins (referred to as the changed proteins) and determine how their expression and/or phosphorylation dynamically changed in association with excitotoxic cell death. Our data, available in ProteomeXchange with identifier PXD008353, identified over 100 changed proteins exhibiting significant alterations in abundance and/or phosphorylation levels at different time points (5–240 min) in neurons after glutamate overstimulation. Bioinformatic analyses predicted that many of them are components of signalling networks directing defective neuronal morphology and functions. Among them, the well-known neuronal survival regulators including mitogen-activated protein kinases Erk1/2, glycogen synthase kinase 3 (GSK3) and microtubule-associated protein (Tau), were selected for validation by biochemical approaches, which confirmed the findings of the proteomic analysis. Bioinformatic analysis predicted Protein Kinase B (Akt), c-Jun kinase (JNK), cyclin-dependent protein kinase 5 (Cdk5), MAP kinase kinase (MEK), Casein kinase 2 (CK2), Rho-activated protein kinase (Rock) and Serum/glucocorticoid-regulated kinase 1 (SGK1) as the potential upstream kinases phosphorylating some of the changed proteins. Further biochemical investigation confirmed the predictions of sustained changes of the activation states of neuronal Akt and CK2 in excitotoxicity. Thus, future investigation to define the signalling pathways directing the dynamic alterations in abundance and phosphorylation of the identified changed neuronal proteins will help elucidate the molecular mechanism of neuronal death in excitotoxicity.
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Affiliation(s)
- Ashfaqul Hoque
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.,Metabolic Signalling Laboratory, St. Vincent's Institute for Medical Research, University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Nicholas A Williamson
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - S Sadia Ameen
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Giuseppe D Ciccotosto
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, 3010, Australia
| | - M Iqbal Hossain
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia.,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Jonathan S Oakhill
- Metabolic Signalling Laboratory, St. Vincent's Institute for Medical Research, University of Melbourne, Fitzroy, VIC, 3065, Australia.,Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, 3000, Australia
| | - Dominic C H Ng
- School of Biomedical Sciences, University of Queensland, St. Lucia, QLD, Australia
| | - Ching-Seng Ang
- Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, VIC, 3010, Australia. .,Cell Signalling Research Laboratories, University of Melbourne, Parkville, VIC, 3010, Australia. .,Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, 3010, Australia.
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14
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Li K, Zhou H, Zhan L, Shi Z, Sun W, Liu D, Liu L, Liang D, Tan Y, Xu W, Xu E. Hypoxic Preconditioning Maintains GLT-1 Against Transient Global Cerebral Ischemia Through Upregulating Cx43 and Inhibiting c-Src. Front Mol Neurosci 2018; 11:344. [PMID: 30323740 PMCID: PMC6172853 DOI: 10.3389/fnmol.2018.00344] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 09/03/2018] [Indexed: 01/06/2023] Open
Abstract
Transient global cerebral ischemia (tGCI) causes excessive release of glutamate from neurons. Astrocytic glutamate transporter-1 (GLT-1) and glutamine synthetase (GS) together play a predominant role in maintaining glutamate at normal extracellular concentrations. Though our previous studies reported the alleviation of tGCI-induced neuronal death by hypoxic preconditioning (HPC) in hippocampal Cornu Ammonis 1 (CA1) of adult rats, the underlying mechanism has not yet been fully elaborated. In this study, we aimed to investigate the roles of GLT-1 and GS in the neuroprotection mediated by HPC against tGCI and to ascertain whether these roles can be regulated by connexin 43 (Cx43) and cellular-Src (c-Src) activity. We found that HPC decreased the level of extracellular glutamate in CA1 after tGCI via maintenance of GLT-1 expression and GS activity. Inhibition of GLT-1 expression with dihydrokainate (DHK) or inhibition of GS activity with methionine sulfoximine (MSO) abolished the neuroprotection induced by HPC. Also, HPC markedly upregulated Cx43 and inhibited p-c-Src expression in CA1 after tGCI, whereas inhibition of Cx43 with Gap26 dramatically reversed this effect. Furthermore, inhibition of p-c-Src with 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo (3, 4-d) pyrimidine (PP2) decreased c-Src activity, increased protein levels of GLT-1 and Cx43, enhanced GS activity, and thus reduced extracellular glutamate level in CA1 after tGCI. Collectively, our data demonstrated that reduced extracellular glutamate induced by HPC against tGCI through preventing the reduction of GLT-1 expression and maintaining GS activity in hippocampal CA1, which was mediated by upregulating Cx43 expression and inhibiting c-Src activity.
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Affiliation(s)
- Kongping Li
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Huarong Zhou
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Lixuan Zhan
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Zhe Shi
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Weiwen Sun
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Dandan Liu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Liu Liu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Donghai Liang
- Department of Environmental Health Sciences, Rollins School of Public Health, Emory University, Atlanta, GA, United States
| | - Yafu Tan
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China.,Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Wensheng Xu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - En Xu
- Institute of Neurosciences and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
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15
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A Ser75-to-Asp phospho-mimicking mutation in Src accelerates ageing-related loss of retinal ganglion cells in mice. Sci Rep 2017; 7:16779. [PMID: 29196663 PMCID: PMC5711949 DOI: 10.1038/s41598-017-16872-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/18/2017] [Indexed: 11/08/2022] Open
Abstract
Src knockout mice show no detectable abnormalities in central nervous system (CNS) post-mitotic neurons, likely reflecting functional compensation by other Src family kinases. Cdk1- or Cdk5-dependent Ser75 phosphorylation in the amino-terminal Unique domain of Src, which shares no homology with other Src family kinases, regulates the stability of active Src. To clarify the roles of Src Ser75 phosphorylation in CNS neurons, we established two types of mutant mice with mutations in Src: phospho-mimicking Ser75Asp (SD) and non-phosphorylatable Ser75Ala (SA). In ageing SD/SD mice, retinal ganglion cell (RGC) number in whole retinas was significantly lower than that in young SD/SD mice in the absence of inflammation and elevated intraocular pressure, resembling the pathogenesis of progressive optic neuropathy. By contrast, SA/SA mice and wild-type (WT) mice exhibited no age-related RGC loss. The age-related retinal RGC number reduction was greater in the peripheral rather than the mid-peripheral region of the retina in SD/SD mice. Furthermore, Rho-associated kinase activity in whole retinas of ageing SD/SD mice was significantly higher than that in young SD/SD mice. These results suggest that Src regulates RGC survival during ageing in a manner that depends on Ser75 phosphorylation.
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16
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Kanchi MM, Shanmugam MK, Rane G, Sethi G, Kumar AP. Tocotrienols: the unsaturated sidekick shifting new paradigms in vitamin E therapeutics. Drug Discov Today 2017; 22:1765-1781. [PMID: 28789906 DOI: 10.1016/j.drudis.2017.08.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/01/2017] [Accepted: 08/01/2017] [Indexed: 11/15/2022]
Abstract
Vitamin E family members: tocotrienols and tocopherols are widely known for their health benefits. Decades of research on tocotrienols have shown they have diverse biological activities such as antioxidant, anti-inflammatory, anticancer, neuroprotective and skin protection benefits, as well as improved cognition, bone health, longevity and reduction of cholesterol levels in plasma. Tocotrienols also modulate several intracellular molecular targets and, most importantly, have been shown to improve lipid profiles, reduce total cholesterol and reduce the volume of white matter lesions in human clinical trials. This review provides a comprehensive update on the little-known therapeutic potentials of tocotrienols, which tocopherols lack in a variety of inflammation-driven diseases.
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Affiliation(s)
- Madhu M Kanchi
- Cancer Science Institute of Singapore, National University of Singapore, 117599, Singapore
| | - Muthu K Shanmugam
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore
| | - Grishma Rane
- Cancer Science Institute of Singapore, National University of Singapore, 117599, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; School of Biomedical Sciences, Curtin Health Innovation Research Institute, Curtin University, Perth, WA 6102, Australia.
| | - Alan P Kumar
- Cancer Science Institute of Singapore, National University of Singapore, 117599, Singapore; Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 117600, Singapore; National University Cancer Institute, National University Health System, 119074, Singapore; Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia; Medical Science Cluster, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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17
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Epidermal E-Cadherin Dependent β-Catenin Pathway Is Phytochemical Inducible and Accelerates Anagen Hair Cycling. Mol Ther 2017; 25:2502-2512. [PMID: 28803863 DOI: 10.1016/j.ymthe.2017.07.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 07/06/2017] [Accepted: 07/16/2017] [Indexed: 01/29/2023] Open
Abstract
Unlike the epidermis, which regenerates continually, hair follicles anchored in the subcutis periodically regenerate by spontaneous repetitive cycles of growth (anagen), degeneration (catagen), and rest (telogen). The loss of hair follicles in response to injuries or pathologies such as alopecia endangers certain inherent functions of the skin. Thus, it is of interest to understand mechanisms underlying follicular regeneration in adults. In this work, a phytochemical rich in the natural vitamin E tocotrienol (TRF) served as a productive tool to unveil a novel epidermal pathway of hair follicular regeneration. Topical TRF application markedly induced epidermal hair follicle development akin to that during fetal skin development. This was observed in the skin of healthy as well as diabetic mice, which are known to be resistant to anagen hair cycling. TRF suppressed epidermal E-cadherin followed by 4-fold induction of β-catenin and its nuclear translocation. Nuclear β-catenin interacted with Tcf3. Such sequestration of Tcf3 from its otherwise known function to repress pluripotent factors induced the plasticity factors Oct4, Sox9, Klf4, c-Myc, and Nanog. Pharmacological inhibition of β-catenin arrested anagen hair cycling by TRF. This work reports epidermal E-cadherin/β-catenin as a novel pathway capable of inducing developmental folliculogenesis in the adult skin.
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18
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Khanna S, Stewart R, Gnyawali S, Harris H, Balch M, Spieldenner J, Sen CK, Rink C. Phytoestrogen isoflavone intervention to engage the neuroprotective effect of glutamate oxaloacetate transaminase against stroke. FASEB J 2017; 31:4533-4544. [PMID: 28655710 DOI: 10.1096/fj.201700353] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/12/2017] [Indexed: 12/15/2022]
Abstract
In the pathophysiologic setting of cerebral ischemia, excitotoxic levels of glutamate contribute to neuronal cell death. Our previous work demonstrated the ability of glutamate oxaloacetate transaminase (GOT) to metabolize neurotoxic glutamate in the stroke-affected brain. Here, we seek to identify small-molecule inducers of GOT expression to mitigate ischemic stroke injury. From a panel of phytoestrogen isoflavones, biochanin A (BCA) was identified as the most potent inducer of GOT gene expression in neural cells. BCA significantly increased GOT mRNA and protein expression at 24 h and protected against glutamate-induced cell death. Of note, this protection was lost when GOT was knocked down. To validate outcomes in vivo, C57BL/6 mice were intraperitoneally injected with BCA (5 and 10 mg/kg) for 4 wk and subjected to ischemic stroke. BCA levels were significantly increased in plasma and brain of mice. Immunohistochemistry demonstrated increased GOT protein expression in the brain. BCA attenuated stroke lesion volume as measured by 9.4T MRI and improved sensorimotor function-this protection was lost with GOT knockdown. BCA increased luciferase activity in cells that were transfected with the pERRE3tk-LUC plasmid, which demonstrated transactivation of GOT. This increase was lost when estrogen-related receptor response element sites were mutated. Taken together, BCA represents a natural phytoestrogen that mitigates stroke-induced injury by inducing GOT expression.-Khanna, S., Stewart, R., Gnyawali, S., Harris, H., Balch, M., Spieldenner, J., Sen, C. K., Rink, C. Phytoestrogen isoflavone intervention to engage the neuroprotective effect of glutamate oxaloacetate transaminase against stroke.
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Affiliation(s)
- Savita Khanna
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Richard Stewart
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Surya Gnyawali
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Hallie Harris
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Maria Balch
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - James Spieldenner
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Chandan K Sen
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Cameron Rink
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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19
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Rink C, Gnyawali S, Stewart R, Teplitsky S, Harris H, Roy S, Sen CK, Khanna S. Glutamate oxaloacetate transaminase enables anaplerotic refilling of TCA cycle intermediates in stroke-affected brain. FASEB J 2017; 31:1709-1718. [PMID: 28096234 DOI: 10.1096/fj.201601033r] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 01/03/2017] [Indexed: 12/30/2022]
Abstract
Ischemic stroke results in excessive release of glutamate, which contributes to neuronal cell death. Here, we test the hypothesis that otherwise neurotoxic glutamate can be productively metabolized by glutamate oxaloacetate transaminase (GOT) to maintain cellular energetics and protect the brain from ischemic stroke injury. The GOT-dependent metabolism of glutamate was studied in primary neural cells and in stroke-affected C57-BL6 mice using magnetic resonance spectroscopy and GC-MS. Extracellular Glu sustained cell viability under hypoglycemic conditions and increased GOT-mediated metabolism in vitro Correction of stroke-induced hypoxia using supplemental oxygen in vivo lowered Glu levels as measured by 1H magnetic resonance spectroscopy. GOT knockdown abrogated this effect and caused ATP loss in the stroke-affected brain. GOT overexpression increased anaplerotic refilling of tricarboxylic acid cycle intermediates in mouse brain during ischemic stroke. Furthermore, GOT overexpression not only reduced ischemic stroke lesion volume but also attenuated neurodegeneration and improved poststroke sensorimotor function. Taken together, our results support a new paradigm that GOT enables metabolism of otherwise neurotoxic extracellular Glu through a truncated tricarboxylic acid cycle under hypoglycemic conditions.-Rink, C., Gnyawali, S., Stewart, R., Teplitsky, S., Harris, H., Roy, S., Sen, C. K., Khanna, S. Glutamate oxaloacetate transaminase enables anaplerotic refilling of TCA cycle intermediates in stroke-affected brain.
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Affiliation(s)
- Cameron Rink
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Surya Gnyawali
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Richard Stewart
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Seth Teplitsky
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Hallie Harris
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Sashwati Roy
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Chandan K Sen
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Savita Khanna
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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20
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Gordillo GM, Biswas A, Khanna S, Spieldenner JM, Pan X, Sen CK. Multidrug Resistance-associated Protein-1 (MRP-1)-dependent Glutathione Disulfide (GSSG) Efflux as a Critical Survival Factor for Oxidant-enriched Tumorigenic Endothelial Cells. J Biol Chem 2016; 291:10089-103. [PMID: 26961872 DOI: 10.1074/jbc.m115.688879] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 12/28/2022] Open
Abstract
Endothelial cell tumors are the most common soft tissue tumors in infants. Tumor-forming endothelial (EOMA) cells are able to escape cell death fate despite excessive nuclear oxidant burden. Our previous work recognized perinuclear Nox-4 as a key contributor to EOMA growth. The objective of this work was to characterize the mechanisms by which EOMA cells evade oxidant toxicity and thrive. In EOMA cells, compared with in the cytosol, the nuclear GSSG/GSH ratio was 5-fold higher. Compared to the ratio observed in healthy murine aortic endothelial (MAE) cells, GSSG/GSH was over twice as high in EOMA cells. Multidrug resistance-associated protein-1 (MRP-1), an active GSSG efflux mechanism, showed 2-fold increased activity in EOMA compared with MAE cells. Hyperactive YB-1 and Ape/Ref-1 were responsible for high MRP-1 expression in EOMA. Proximity ligand assay demonstrated MRP-1 and YB-1 binding. Such binding enabled the nuclear targeting of MRP-1 in EOMA in a leptomycin-B-sensitive manner. MRP-1 inhibition as well as knockdown trapped nuclear GSSG, causing cell death of EOMA. Disulfide loading of cells by inhibition of GSSG reductase (bischoloronitrosourea) or thioredoxin reductase (auranofin) was effective in causing EOMA death as well. In sum, EOMA cells survive a heavy oxidant burden by rapid efflux of GSSG, which is lethal if trapped within the cell. A hyperactive MRP-1 system for GSSG efflux acts as a critical survival factor for these cells, making it a potential target for EOMA therapeutics.
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Affiliation(s)
- Gayle M Gordillo
- From the Department of Plastic Surgery, Davis Heart and Lung Research Institute, and
| | - Ayan Biswas
- From the Department of Plastic Surgery, Davis Heart and Lung Research Institute, and
| | - Savita Khanna
- Davis Heart and Lung Research Institute, and Department of Surgery
| | | | - Xueliang Pan
- Center for Biostatistics, Ohio State University Wexner Medical Center, Columbus, Ohio 43212
| | - Chandan K Sen
- Davis Heart and Lung Research Institute, and Department of Surgery
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Barrier Function of the Repaired Skin Is Disrupted Following Arrest of Dicer in Keratinocytes. Mol Ther 2015; 23:1201-1210. [PMID: 25896246 DOI: 10.1038/mt.2015.65] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 04/07/2015] [Indexed: 02/07/2023] Open
Abstract
Tissue injury transiently silences miRNA-dependent posttranscriptional gene silencing in its effort to unleash adult tissue repair. Once the wound is closed, miRNA biogenesis is induced averting neoplasia. In this work, we report that Dicer plays an important role in reestablishing the barrier function of the skin post-wounding via a miRNA-dependent mechanism. MicroRNA expression profiling of skin and wound-edge tissue revealed global upregulation of miRNAs following wound closure at day 14 post-wounding with significant induction of Dicer expression. Barrier function of the skin, as measured by trans-epidermal water loss, was compromised in keratinocyte-specific conditional (K14/Lox-Cre) Dicer-ablated mice because of malformed cornified epithelium lacking loricrin expression. Studies on human keratinocytes recognized that loricrin expression was inversely related to the expression of the cyclin-dependent kinase inhibitor p21(Waf1/Cip1). Compared to healthy epidermis, wound-edge keratinocytes from Dicer-ablated skin epidermis revealed elevated p21(Waf1/Cip1) expression. Adenoviral and pharmacological suppression of p21(Waf1/Cip1) in keratinocyte-specific conditional Dicer-ablated mice improved wound healing indicating a role of Dicer in the suppression of p21(Waf1/Cip1). This work upholds p21(Waf1/Cip1) as a druggable target to restore barrier function of skin suffering from loss of Dicer function as would be expected in diabetes and other forms of oxidant insult.
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Ahsan H, Ahad A, Iqbal J, Siddiqui WA. Pharmacological potential of tocotrienols: a review. Nutr Metab (Lond) 2014; 11:52. [PMID: 25435896 PMCID: PMC4247006 DOI: 10.1186/1743-7075-11-52] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/15/2014] [Indexed: 02/06/2023] Open
Abstract
Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley, and certain types of nuts and grains. Like tocopherols, tocotrienols are also of four types viz. alpha, beta, gamma and delta. Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. Tocopherols are lipophilic in nature and are found in association with lipoproteins, fat deposits and cellular membranes and protect the polyunsaturated fatty acids from peroxidation reactions. The unsaturated chain of tocotrienol allows an efficient penetration into tissues that have saturated fatty layers such as the brain and liver. Recent mechanistic studies indicate that other forms of vitamin E, such as γ-tocopherol, δ-tocopherol, and γ-tocotrienol, have unique antioxidant and anti-inflammatory properties that are superior to those of α-tocopherol against chronic diseases. These forms scavenge reactive nitrogen species, inhibit cyclooxygenase- and 5-lipoxygenase-catalyzed eicosanoids and suppress proinflammatory signalling, such as NF-κB and STAT. The animal and human studies show tocotrienols may be useful against inflammation-associated diseases. Many of the functions of tocotrienols are related to its antioxidant properties and its varied effects are due to it behaving as a signalling molecule. Tocotrienols exhibit biological activities that are also exhibited by tocopherols, such as neuroprotective, anti-cancer, anti-inflammatory and cholesterol lowering properties. Hence, effort has been made to compile the different functions and properties of tocotrienols in experimental model systems and humans. This article constitutes an in-depth review of the pharmacology, metabolism, toxicology and biosafety aspects of tocotrienols. Tocotrienols are detectable at appreciable levels in the plasma after supplementations. However, there is inadequate data on the plasma concentrations of tocotrienols that are sufficient to demonstrate significant physiological effect and biodistribution studies show their accumulation in vital organs of the body. Considering the wide range of benefits that tocotrienols possesses against some common human ailments and having a promising potential, the experimental analysis accounts for about a small fraction of all vitamin E research. The current state of knowledge deserves further investigation into this lesser known form of vitamin E.
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Affiliation(s)
- Haseeb Ahsan
- Department of Biochemistry, Faculty of Dentistry, Jamia Millia Islamia, New Delhi, 110025 India
| | - Amjid Ahad
- Department of Biochemistry, Jamia Hamdard (Hamdard University), New Delhi, 110062 India
| | - Jahangir Iqbal
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203 USA
| | - Waseem A Siddiqui
- Department of Biochemistry, Jamia Hamdard (Hamdard University), New Delhi, 110062 India
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The estrogen receptor β-PI3K/Akt pathway mediates the cytoprotective effects of tocotrienol in a cellular Parkinson's disease model. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1303-12. [DOI: 10.1016/j.bbadis.2014.04.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/20/2014] [Accepted: 04/07/2014] [Indexed: 11/18/2022]
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24
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Ahsan H, Ahad A, Iqbal J, Siddiqui WA. Pharmacological potential of tocotrienols: a review. Nutr Metab (Lond) 2014. [PMID: 25435896 DOI: 10.1186/743-7075-11-52] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley, and certain types of nuts and grains. Like tocopherols, tocotrienols are also of four types viz. alpha, beta, gamma and delta. Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. Tocopherols are lipophilic in nature and are found in association with lipoproteins, fat deposits and cellular membranes and protect the polyunsaturated fatty acids from peroxidation reactions. The unsaturated chain of tocotrienol allows an efficient penetration into tissues that have saturated fatty layers such as the brain and liver. Recent mechanistic studies indicate that other forms of vitamin E, such as γ-tocopherol, δ-tocopherol, and γ-tocotrienol, have unique antioxidant and anti-inflammatory properties that are superior to those of α-tocopherol against chronic diseases. These forms scavenge reactive nitrogen species, inhibit cyclooxygenase- and 5-lipoxygenase-catalyzed eicosanoids and suppress proinflammatory signalling, such as NF-κB and STAT. The animal and human studies show tocotrienols may be useful against inflammation-associated diseases. Many of the functions of tocotrienols are related to its antioxidant properties and its varied effects are due to it behaving as a signalling molecule. Tocotrienols exhibit biological activities that are also exhibited by tocopherols, such as neuroprotective, anti-cancer, anti-inflammatory and cholesterol lowering properties. Hence, effort has been made to compile the different functions and properties of tocotrienols in experimental model systems and humans. This article constitutes an in-depth review of the pharmacology, metabolism, toxicology and biosafety aspects of tocotrienols. Tocotrienols are detectable at appreciable levels in the plasma after supplementations. However, there is inadequate data on the plasma concentrations of tocotrienols that are sufficient to demonstrate significant physiological effect and biodistribution studies show their accumulation in vital organs of the body. Considering the wide range of benefits that tocotrienols possesses against some common human ailments and having a promising potential, the experimental analysis accounts for about a small fraction of all vitamin E research. The current state of knowledge deserves further investigation into this lesser known form of vitamin E.
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Affiliation(s)
- Haseeb Ahsan
- Department of Biochemistry, Faculty of Dentistry, Jamia Millia Islamia, New Delhi, 110025 India
| | - Amjid Ahad
- Department of Biochemistry, Jamia Hamdard (Hamdard University), New Delhi, 110062 India
| | - Jahangir Iqbal
- Department of Cell Biology and Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY 11203 USA
| | - Waseem A Siddiqui
- Department of Biochemistry, Jamia Hamdard (Hamdard University), New Delhi, 110062 India
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25
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Loss of miR-29b following acute ischemic stroke contributes to neural cell death and infarct size. J Cereb Blood Flow Metab 2013; 33:1197-206. [PMID: 23632968 PMCID: PMC3734770 DOI: 10.1038/jcbfm.2013.68] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/05/2013] [Accepted: 04/08/2013] [Indexed: 01/31/2023]
Abstract
Glutathione depletion and 12-lipoxygenase-dependent metabolism of arachidonic acid are known to be implicated in neurodegeneration associated with acute ischemic stroke. The objective of this study was to investigate the significance of miR-29 in neurodegeneration associated with acute ischemic stroke. Neural cell death caused by arachidonic acid insult of glutathione-deficient cells was preceded by a 12-lipoxygenase-dependent loss of miR-29b. Delivery of miR-29b mimic to blunt such loss was neuroprotective. miR-29b inhibition potentiated such neural cell death. 12-Lipoxygenase knockdown and inhibitors attenuated the loss of miR-29b in challenged cells. In vivo, stroke caused by middle-cerebral artery occlusion was followed by higher 12-lipoxygenase activity and loss of miR-29b as detected in laser-captured infarct site tissue. 12-Lipoxygenase knockout mice demonstrated protection against such miR loss. miR-29b gene delivery markedly attenuated stroke-induced brain lesion. Oral supplementation of α-tocotrienol, a vitamin E 12-lipoxygenase inhibitor, rescued stroke-induced loss of miR-29b and minimized lesion size. This work provides the first evidence demonstrating that loss of miR-29b at the infarct site is a key contributor to stroke lesion. Such loss is contributed by activity of the 12-lipoxygenase pathway providing maiden evidence linking arachidonic acid metabolism to miR-dependent mechanisms in stroke.
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26
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Hossain MI, Roulston CL, Kamaruddin MA, Chu PWY, Ng DCH, Dusting GJ, Bjorge JD, Williamson NA, Fujita DJ, Cheung SN, Chan TO, Hill AF, Cheng HC. A truncated fragment of Src protein kinase generated by calpain-mediated cleavage is a mediator of neuronal death in excitotoxicity. J Biol Chem 2013; 288:9696-9709. [PMID: 23400779 DOI: 10.1074/jbc.m112.419713] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Excitotoxicity resulting from overstimulation of glutamate receptors is a major cause of neuronal death in cerebral ischemic stroke. The overstimulated ionotropic glutamate receptors exert their neurotoxic effects in part by overactivation of calpains, which induce neuronal death by catalyzing limited proteolysis of specific cellular proteins. Here, we report that in cultured cortical neurons and in vivo in a rat model of focal ischemic stroke, the tyrosine kinase Src is cleaved by calpains at a site in the N-terminal unique domain. This generates a truncated Src fragment of ~52 kDa, which we localized predominantly to the cytosol. A cell membrane-permeable fusion peptide derived from the unique domain of Src prevents calpain from cleaving Src in neurons and protects against excitotoxic neuronal death. To explore the role of the truncated Src fragment in neuronal death, we expressed a recombinant truncated Src fragment in cultured neurons and examined how it affects neuronal survival. Expression of this fragment, which lacks the myristoylation motif and unique domain, was sufficient to induce neuronal death. Furthermore, inactivation of the prosurvival kinase Akt is a key step in its neurotoxic signaling pathway. Because Src maintains neuronal survival, our results implicate calpain cleavage as a molecular switch converting Src from a promoter of cell survival to a mediator of neuronal death in excitotoxicity. Besides unveiling a new pathological action of Src, our discovery of the neurotoxic action of the truncated Src fragment suggests new therapeutic strategies with the potential to minimize brain damage in ischemic stroke.
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Affiliation(s)
- M Iqbal Hossain
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Carli L Roulston
- O'Brien Institute, 42 Fitzroy Street, Fitzroy, Victoria 3065, Australia; Centre for Eye Research Australia, University of Melbourne, Gisborne Street, East Melbourne 3002, Australia
| | - M Aizuddin Kamaruddin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Percy W Y Chu
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Dominic C H Ng
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Gregory J Dusting
- O'Brien Institute, 42 Fitzroy Street, Fitzroy, Victoria 3065, Australia; Centre for Eye Research Australia, University of Melbourne, Gisborne Street, East Melbourne 3002, Australia
| | - Jeffrey D Bjorge
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Health Sciences Centre, Calgary, Alberta T2N 4N1, Canada
| | - Nicholas A Williamson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Donald J Fujita
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Health Sciences Centre, Calgary, Alberta T2N 4N1, Canada
| | - Steve N Cheung
- Centre for Cellular and Molecular Biology, School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia
| | - Tung O Chan
- Department of Medicine, Center for Translational Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Andrew F Hill
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia
| | - Heung-Chin Cheng
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, 30 Flemington Road, Parkville, Victoria 3010, Australia.
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Ogura M, Yamaki J, Homma M, Homma Y. Mitochondrial c-Src regulates cell survival through phosphorylation of respiratory chain components. Biochem J 2012; 447:281-9. [PMID: 22823520 PMCID: PMC3459221 DOI: 10.1042/bj20120509] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 07/17/2012] [Accepted: 07/24/2012] [Indexed: 12/26/2022]
Abstract
Mitochondrial protein tyrosine phosphorylation is an important mechanism for the modulation of mitochondrial functions. In the present study, we have identified novel substrates of c-Src in mitochondria and investigated their function in the regulation of oxidative phosphorylation. The Src family kinase inhibitor PP2 {amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3,4d] pyrimidine} exhibits significant reduction of respiration. Similar results were obtained from cells expressing kinase-dead c-Src, which harbours a mitochondrial-targeting sequence. Phosphorylation-site analysis selects c-Src targets, including NDUFV2 (NADH dehydrogenase [ubiquinone] flavoprotein 2) at Tyr(193) of respiratory complex I and SDHA (succinate dehydrogenase A) at Tyr(215) of complex II. The phosphorylation of these sites by c-Src is supported by an in vivo assay using cells expressing their phosphorylation-defective mutants. Comparison of cells expressing wild-type proteins and their mutants reveals that NDUFV2 phosphorylation is required for NADH dehydrogenase activity, affecting respiration activity and cellular ATP content. SDHA phosphorylation shows no effect on enzyme activity, but perturbed electron transfer, which induces reactive oxygen species. Loss of viability is observed in T98G cells and the primary neurons expressing these mutants. These results suggest that mitochondrial c-Src regulates the oxidative phosphorylation system by phosphorylating respiratory components and that c-Src activity is essential for cell viability.
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Key Words
- cell death
- energy metabolism
- mitochondrion
- src
- tyrosine kinase
- reactive oxygen species (ros)
- ant, adenine nucleotide translocase
- bn, blue native
- ca, constitutive-active
- cox, cytochrome c oxidase
- csk, c-terminal src kinase
- ddm, n-dodecyl-β-d-maltoside
- 2-de, two-dimensional page
- he, hydroethidine
- hek, human embryonic kidney
- ipg, immobilized ph gradient
- kd, kinase-dead
- ldh, lactate dehydrogenase
- mab, monoclonal antibody
- map2, microtubule-associated protein 2
- mts, mitochondria-targeting sequence
- nbt, nitro blue tetrazolium
- ndufb10, nadh dehydrogenase [ubiquinone] 1β subcomplex subunit 10
- ndufv2, nadh dehydrogenase [ubiquinone] flavoprotein 2
- pi, propidium iodide
- pms, phenazine methosulfate
- pp2, amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3,4d] pyrimidine
- ros, reactive oxygen species
- sdha, succinate dehydrogenase a
- sfk, src family kinase
- ucp, uncoupling protein
- vlcad, very long chain acyl-coa dehydrogenase
- wt, wild-type
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Affiliation(s)
- Masato Ogura
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Junko Yamaki
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Miwako K. Homma
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Yoshimi Homma
- Department of Biomolecular Science, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
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28
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Socodato R, Santiago FN, Portugal CC, Domingues AF, Santiago AR, Relvas JB, Ambrósio AF, Paes-de-Carvalho R. Calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors trigger neuronal nitric-oxide synthase activation to promote nerve cell death in an Src kinase-dependent fashion. J Biol Chem 2012; 287:38680-94. [PMID: 22992730 DOI: 10.1074/jbc.m112.353961] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In the retina information decoding is dependent on excitatory neurotransmission and is critically modulated by AMPA glutamate receptors. The Src-tyrosine kinase has been implicated in modulating neurotransmission in CNS. Thus, our main goal was to correlate AMPA-mediated excitatory neurotransmission with the modulation of Src activity in retinal neurons. Cultured retinal cells were used to access the effects of AMPA stimulation on nitric oxide (NO) production and Src phosphorylation. 4-Amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence mainly determined NO production, and immunocytochemistry and Western blotting evaluated Src activation. AMPA receptors activation rapidly up-regulated Src phosphorylation at tyrosine 416 (stimulatory site) and down-regulated phosphotyrosine 527 (inhibitory site) in retinal cells, an effect mainly mediated by calcium-permeable AMPA receptors. Interestingly, experiments confirmed that neuronal NOS was activated in response to calcium-permeable AMPA receptor stimulation. Moreover, data suggest NO pathway as a key regulatory signaling in AMPA-induced Src activation in neurons but not in glial cells. The NO donor SNAP (S-nitroso-N-acetyl-DL-penicillamine) and a soluble guanylyl cyclase agonist (YC-1) mimicked AMPA effect in Src Tyr-416 phosphorylation, reinforcing that Src activation is indeed modulated by the NO pathway. Gain and loss-of-function data demonstrated that ERK is a downstream target of AMPA-induced Src activation and NO signaling. Furthermore, AMPA stimulated NO production in organotypic retinal cultures and increased Src activity in the in vivo retina. Additionally, AMPA-induced apoptotic retinal cell death was regulated by both NOS and Src activity. Because Src activity is pivotal in several CNS regions, the data presented herein highlight that Src modulation is a critical step in excitatory retinal cell death.
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Affiliation(s)
- Renato Socodato
- Program of Neurosciences and Department of Neurobiology, Institute of Biology, Fluminense Federal University, Niterói, 24020-971, Brazil
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29
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Hossain MI, Kamaruddin MA, Cheng HC. Aberrant regulation and function of Src family tyrosine kinases: Their potential contributions to glutamate-induced neurotoxicity. Clin Exp Pharmacol Physiol 2012; 39:684-91. [DOI: 10.1111/j.1440-1681.2011.05621.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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30
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Roy S, Driggs J, Elgharably H, Biswas S, Findley M, Khanna S, Gnyawali U, Bergdall VK, Sen CK. Platelet-rich fibrin matrix improves wound angiogenesis via inducing endothelial cell proliferation. Wound Repair Regen 2012; 19:753-66. [PMID: 22092846 DOI: 10.1111/j.1524-475x.2011.00740.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The economic, social, and public health burden of chronic ulcers and other compromised wounds is enormous and rapidly increasing with the aging population. The growth factors derived from platelets play an important role in tissue remodeling including neovascularization. Platelet-rich plasma (PRP) has been utilized and studied for the last four decades. Platelet gel and fibrin sealant, derived from PRP mixed with thrombin and calcium chloride, have been exogenously applied to tissues to promote wound healing, bone growth, hemostasis, and tissue sealing. In this study, we first characterized recovery and viability of as well as growth factor release from platelets in a novel preparation of platelet gel and fibrin matrix, namely platelet-rich fibrin matrix (PRFM). Next, the effect of PRFM application in a delayed model of ischemic wound angiogenesis was investigated. The study, for the first time, shows the kinetics of the viability of platelet-embedded fibrin matrix. A slow and steady release of growth factors from PRFM was observed. The vascular endothelial growth factor released from PRFM was primarily responsible for endothelial mitogenic response via extracellular signal-regulated protein kinase activation pathway. Finally, this preparation of PRFM effectively induced endothelial cell proliferation and improved wound angiogenesis in chronic wounds, providing evidence of probable mechanisms of action of PRFM in healing of chronic ulcers.
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Affiliation(s)
- Sashwati Roy
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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31
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Patel V, Rink C, Gordillo GM, Khanna S, Gnyawali U, Roy S, Shneker B, Ganesh K, Phillips G, More JL, Sarkar A, Kirkpatrick R, Elkhammas EA, Klatte E, Miller M, Firstenberg MS, Chiocca EA, Nesaretnam K, Sen CK. Oral tocotrienols are transported to human tissues and delay the progression of the model for end-stage liver disease score in patients. J Nutr 2012; 142:513-9. [PMID: 22298568 PMCID: PMC3278267 DOI: 10.3945/jn.111.151902] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The natural vitamin E family is composed of 8 members equally divided into 2 classes: tocopherols (TCP) and tocotrienols (TE). A growing body of evidence suggests TE possess potent biological activity not shared by TCP. The primary objective of this work was to determine the concentrations of TE (200 mg mixed TE, b.i.d.) and TCP [200 mg α-TCP, b.i.d.)] in vital tissues and organs of adults receiving oral supplementation. Eighty participants were studied. Skin and blood vitamin E concentrations were determined from healthy participants following 12 wk of oral supplementation of TE or TCP. Vital organ vitamin E levels were determined by HPLC in adipose, brain, cardiac muscle, and liver of surgical patients following oral TE or TCP supplementation (mean duration, 20 wk; range, 1-96 wk). Oral supplementation of TE significantly increased the TE tissue concentrations in blood, skin, adipose, brain, cardiac muscle, and liver over time. α-TE was delivered to human brain at a concentration reported to be neuroprotective in experimental models of stroke. In prospective liver transplantation patients, oral TE lowered the model for end-stage liver disease (MELD) score in 50% of patients supplemented, whereas only 20% of TCP-supplemented patients demonstrated a reduction in MELD score. This work provides, to our knowledge, the first evidence demonstrating that orally supplemented TE are transported to vital organs of adult humans. The findings of this study, in the context of the current literature, lay the foundation for Phase II clinical trials testing the efficacy of TE against stroke and end-stage liver disease in humans.
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Affiliation(s)
| | | | | | | | | | | | - Bassel Shneker
- Department of Neurology, The Ohio State University Medical Center, Columbus, OH
| | | | - Gary Phillips
- Center for Biostatistics, The Ohio State University, Columbus, OH
| | - J. Layne More
- Department of Neurology, The Ohio State University Medical Center, Columbus, OH
| | | | | | | | - Emily Klatte
- Department of Neurology, The Ohio State University Medical Center, Columbus, OH
| | | | | | | | - Kalanithi Nesaretnam
- Food Technology and Nutrition Unit, Malaysian Palm Oil Board, Selangor, Malaysia
| | - Chandan K. Sen
- Department of Surgery,To whom correspondence should be addressed. E-mail:
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32
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Frank J, Chin XWD, Schrader C, Eckert GP, Rimbach G. Do tocotrienols have potential as neuroprotective dietary factors? Ageing Res Rev 2012; 11:163-80. [PMID: 21763788 DOI: 10.1016/j.arr.2011.06.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/28/2011] [Accepted: 06/30/2011] [Indexed: 11/17/2022]
Abstract
Tocotrienols (T(3)) belong to the family of vitamin E compounds (α-, β-, γ-, δ-tocopherols and -tocotrienols) and have unique biological properties that make them potential neuroprotective dietary factors. In addition to their antioxidant activity, T(3) at micromolar concentrations exert cholesterol-lowering activities in cells, animal models and some, but not all, human studies by means of inhibition of the activity of the rate-limiting enzyme in cholesterol biosynthesis, 3-hydroxy-3-methylglutaryl coenzyme A reductase. At lower concentrations (∼10 nmol/L), T(3) modulate signalling pathways involved in neuronal cell death in cell culture experiments. Targets of T(3) include prenyl transferases, non-receptor tyrosine kinase, phospholipase A(2), 12-lipoxygenase, cyclooxygenase-2, and nuclear factor κB. The low bioavailability and rapid excretion of T(3) represents a major hurdle in their preventive use. Fasting plasma concentrations, even after supplementation with high doses, are below 1 μmol/L. T(3) bioavailability may be enhanced by ingestion with a high-fat meal, self-emulsifying drug delivery systems, or phytochemicals that inhibit T(3) metabolism and excretion. T(3) have no known adverse effects when consumed as part of a normal diet and the studies reviewed here support the notion that they may have potential as neuroprotective agents. However, experiments in relevant animal models and randomised human intervention trials addressing the neuroprotection mediated by T(3) are scarce and, thus, highly warranted.
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Affiliation(s)
- Jan Frank
- Institute of Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, Germany.
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Groveman BR, Feng S, Fang XQ, Pflueger M, Lin SX, Bienkiewicz EA, Yu X. The regulation of N-methyl-D-aspartate receptors by Src kinase. FEBS J 2011; 279:20-8. [PMID: 22060915 DOI: 10.1111/j.1742-4658.2011.08413.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Src family kinases (SFKs) play critical roles in the regulation of many cellular functions by growth factors, G-protein-coupled receptors and ligand-gated ion channels. Recent data have shown that SFKs serve as a convergent point of multiple signaling pathways regulating N-methyl-d-aspartate (NMDA) receptors in the central nervous system. Multiple SFK molecules, such as Src and Fyn, closely associate with their substrate, NMDA receptors, via indirect and direct binding mechanisms. The NMDA receptor is associated with an SFK signaling complex consisting of SFKs; the SFK-activating phosphatase, protein tyrosine phosphatase α; and the SFK-inactivating kinase, C-terminal Src kinase. Early studies have demonstrated that intramolecular interactions with the SH2 or SH3 domain lock SFKs in a closed conformation. Disruption of the interdomain interactions can induce the activation of SFKs with multiple signaling pathways involved in regulation of this process. The enzyme activity of SFKs appears 'graded', exhibiting different levels coinciding with activation states. It has also been proposed that the SH2 and SH3 domains may stimulate catalytic activity of protein tyrosine kinases, such as Abl. Recently, it has been found that the enzyme activity of neuronal Src protein is associated with its stability, and that the SH2 and SH3 domain interactions may act not only to constrain the activation of neuronal Src, but also to regulate the enzyme activity of active neuronal Src. Collectively, these findings demonstrate novel mechanisms underlying the regulation of SFKs.
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Affiliation(s)
- Bradley R Groveman
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA.
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Gnanasekaran A, Sundukova M, van den Maagdenberg AMJM, Fabbretti E, Nistri A. Lipid rafts control P2X3 receptor distribution and function in trigeminal sensory neurons of a transgenic migraine mouse model. Mol Pain 2011; 7:77. [PMID: 21958474 PMCID: PMC3193817 DOI: 10.1186/1744-8069-7-77] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 09/29/2011] [Indexed: 11/29/2022] Open
Abstract
Background A genetic knock-in mouse model expressing the R192Q mutation of the α1-subunit of the CaV2.1 channels frequently found in patients with familial hemiplegic migraine shows functional upregulation of ATP-sensitive P2X3 receptors of trigeminal sensory neurons that transduce nociceptive inputs to the brainstem. In an attempt to understand the basic mechanisms linked to the upregulation of P2X3 receptor activity, we investigated the influence of the lipid domain of these trigeminal sensory neurons on receptor compartmentalization and function. Results Knock-in neurons were strongly enriched with lipid rafts containing a larger fraction of P2X3 receptors at membrane level. Pretreatment with the CaV2.1 channel blocker ω-agatoxin significantly decreased the lipid raft content of KI membranes. After pharmacologically disrupting the cholesterol component of lipid rafts, P2X3 receptors became confined to non-raft compartments and lost their functional potentiation typically observed in KI neurons with whole-cell patch-clamp recording. Following cholesterol depletion, all P2X3 receptor currents decayed more rapidly and showed delayed recovery indicating that alteration of the lipid raft milieu reduced the effectiveness of P2X3 receptor signalling and changed their desensitization process. Kinetic modeling could reproduce the observed data when slower receptor activation was simulated and entry into desensitization was presumed to be faster. Conclusions The more abundant lipid raft compartment of knock-in neurons was enriched in P2X3 receptors that exhibited stronger functional responses. These results suggest that the membrane microenvironment of trigeminal sensory neurons is an important factor in determining sensitization of P2X3 receptors and could contribute to a migraine phenotype by enhancing ATP-mediated responses.
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Affiliation(s)
- Aswini Gnanasekaran
- Neurobiology Sector and Italian Institute of Technology Unit, International School for Advanced Studies, Trieste, Italy
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Kariminejad R, Lind-Thomsen A, Tümer Z, Erdogan F, Ropers HH, Tommerup N, Ullmann R, Møller RS. High frequency of rare copy number variants affecting functionally related genes in patients with structural brain malformations. Hum Mutat 2011; 32:1427-35. [DOI: 10.1002/humu.21585] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 07/26/2011] [Indexed: 01/20/2023]
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Place AT, Chen Z, Bakhshi FR, Liu G, O'Bryan JP, Minshall RD. Cooperative role of caveolin-1 and C-terminal Src kinase binding protein in C-terminal Src kinase-mediated negative regulation of c-Src. Mol Pharmacol 2011; 80:665-72. [PMID: 21778303 DOI: 10.1124/mol.111.073957] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In the present study, we assessed the cooperative roles of C-terminal Src kinase (Csk) binding protein (Cbp) and Caveolin-1 (Cav-1) in the mechanism of Src family tyrosine kinase (SFK) inhibition by Csk. SFKs are inactivated by phosphorylation of their C-terminal tyrosine by Csk. Whereas SFKs are membrane-associated, Csk is a cytoplasmic protein and therefore requires membrane adaptors such as Cbp or Cav-1 for recruitment to the plasma membrane to mediate SFK inhibition. To determine the specific role of Cav-1 and Cbp in SFK inhibition, we measured c-Src activity in the absence of each membrane adaptor. It is noteworthy that in lungs and fibroblasts from Cav-1(-/-) mice, we observed increased expression of Cbp compared with wild-type (WT) controls. However, both c-Src activity and Csk localization at the membrane were similar between Cav-1(-/-) fibroblasts and WT cells. Likewise, Cbp depletion by small interfering RNA (siRNA) treatment of WT cells had no effect on basal c-Src activity, but it increased the phosphorylation state of Cav-1. Immunoprecipitation then confirmed increased association of Csk with phosphomimicking Cav-1. Knockdown of Cbp by siRNA in Cav-1(-/-) cells revealed increased basal c-Src activity, and re-expression of WT Cav-1 in the same cells reduced basal c-Src activity. Taken together, these results indicate that Cav-1 and Cbp cooperatively regulate c-Src activity by recruiting Csk to the membrane where it phosphorylates c-Src inhibitory tyrosine 529. Furthermore, when either Cav-1 or Cbp expression is reduced or absent, there is a compensatory increase in the phosphorylation state or expression level of the other membrane-associated Csk adaptor to maintain SFK inhibition.
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Affiliation(s)
- Aaron T Place
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL 60612, USA
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Georgakopoulos A, Xu J, Xu C, Mauger G, Barthet G, Robakis NK. Presenilin1/gamma-secretase promotes the EphB2-induced phosphorylation of ephrinB2 by regulating phosphoprotein associated with glycosphingolipid-enriched microdomains/Csk binding protein. FASEB J 2011; 25:3594-604. [PMID: 21746865 DOI: 10.1096/fj.11-187856] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Reverse signaling through the ephrinB ligands is important for several morphogenetic events, such as axon guidance, neuronal plasticity, spine maturation, and synaptogenesis. Signaling is initiated by binding of EphB receptors to ephrinB ligands, stimulating their tyrosine phosphorylation via an unclear mechanism. Here we show that this mechanism involves presenilin1 (PS1)/γ-secretase regulation of phosphoprotein associated with glycosphingolipid-enriched microdomains/Csk binding protein (PAG/Cbp), an adaptor protein that controls the activity of Src kinases. Using immunoprecipitation and Western blot of mouse primary neuronal and human embryonic kidney (HEK293) cell extracts overexpressing PAG/Cbp, we show that EphB2 induces tyrosine dephosphorylation of PAG/Cbp in a γ-secretase-dependent manner. In these cells, PAG/Cbp dephosphorylation is promoted by the PS1/γ-secretase-produced fragment of ephrinB2 cleavage (ephrinB2/CTF2), which forms complexes with PAG/Cbp when introduced exogenously. EphB2-induced tyrosine phosphorylation of ephrinB2 depends on PAG/Cbp because EphB2 cannot increase ephrinB2 phosphorylation in cells treated with anti-PAG siRNA or in PAG/Cbp-knockout (KO) cells. Furthermore, in contrast to WT PS1, familial Alzheimer disease (FAD) PS1 mutants expressed in PS1-KO mouse embryonic fibroblasts inhibited both the EphB2-induced dephosphorylation of PAG/Cbp and the phosphorylation of ephrinB2. PS1 FAD mutations may thus inhibit the function of ephrinB in the brain, promoting neurodegeneration in Alzheimer disease.
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Affiliation(s)
- Anastasios Georgakopoulos
- Center for Molecular Biology and Genetics of Neurodegeneration, Department of Psychiatry, Mt. Sinai School of Medicine, New York University, 1 Gustave L. Levy Pl., Box 1229, New York, NY 10029, USA.
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Park HA, Kubicki N, Gnyawali S, Chan YC, Roy S, Khanna S, Sen CK. Natural vitamin E α-tocotrienol protects against ischemic stroke by induction of multidrug resistance-associated protein 1. Stroke 2011; 42:2308-14. [PMID: 21719775 DOI: 10.1161/strokeaha.110.608547] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE α-Tocotrienol (TCT) represents the most potent neuroprotective form of natural vitamin E that is Generally Recognized As Safe certified by the U.S. Food and Drug Administration. This work addresses a novel molecular mechanism by which α-TCT may be protective against stroke in vivo. Elevation of intracellular oxidized glutathione (GSSG) triggers neural cell death. Multidrug resistance-associated protein 1 (MRP1), a key mediator of intracellular oxidized glutathione efflux from neural cells, may therefore possess neuroprotective functions. METHODS Stroke-dependent brain tissue damage was studied in MRP1-deficient mice and α-TCT-supplemented mice. RESULTS Elevated MRP1 expression was observed in glutamate-challenged primary cortical neuronal cells and in stroke-affected brain tissue. MRP1-deficient mice displayed larger stroke-induced lesions, recognizing a protective role of MRP1. In vitro, protection against glutamate-induced neurotoxicity by α-TCT was attenuated under conditions of MRP1 knockdown; this suggests the role of MRP1 in α-TCT-dependent neuroprotection. In vivo studies demonstrated that oral supplementation of α-TCT protected against murine stroke. MRP1 expression was elevated in the stroke-affected cortical tissue of α-TCT-supplemented mice. Efforts to elucidate the underlying mechanism identified MRP1 as a target of microRNA (miR)-199a-5p. In α-TCT-supplemented mice, miR-199a-5p was downregulated in stroke-affected brain tissue. CONCLUSIONS This work recognizes MRP1 as a protective factor against stroke. Furthermore, findings of this study add a new dimension to the current understanding of the molecular bases of α-TCT neuroprotection in 2 ways: by identifying MRP1 as a α-TCT-sensitive target and by unveiling the general prospect that oral α-TCT may regulate miR expression in stroke-affected brain tissue.
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Affiliation(s)
- Han-A Park
- Department of Surgery, Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio, USA
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Rink C, Gnyawali S, Peterson L, Khanna S. Oxygen-inducible glutamate oxaloacetate transaminase as protective switch transforming neurotoxic glutamate to metabolic fuel during acute ischemic stroke. Antioxid Redox Signal 2011; 14:1777-85. [PMID: 21361730 PMCID: PMC3078502 DOI: 10.1089/ars.2011.3930] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This work rests on our previous report (J Cereb Blood Flow Metab 30: 1275-1287, 2010) recognizing that glutamate (Glu) oxaloacetate transaminase (GOT) is induced when brain tissue hypoxia is corrected during acute ischemic stroke (AIS). GOT can metabolize Glu into tricarboxylic acid cycle intermediates and may therefore be useful to harness excess neurotoxic extracellular Glu during AIS as a metabolic substrate. We report that in cultured neural cells challenged with hypoglycemia, extracellular Glu can support cell survival as long as there is sufficient oxygenation. This effect is abrogated by GOT knockdown. In a rodent model of AIS, supplemental oxygen (100% O(2) inhaled) during ischemia significantly increased GOT expression and activity in the stroke-affected brain tissue and prevented loss of ATP. Biochemical analyses and in vivo magnetic resonance spectroscopy during stroke demonstrated that such elevated GOT decreased Glu levels at the stroke-affected site. In vivo lentiviral gene delivery of GOT minimized lesion volume, whereas GOT knockdown worsened stroke outcomes. Thus, brain tissue GOT emerges as a novel target in managing stroke outcomes. This work demonstrates that correction of hypoxia during AIS can help clear extracellular neurotoxic Glu by enabling utilization of this amino acid as a metabolic fuel to support survival of the hypoglycemic brain tissue. Strategies to mitigate extracellular Glu-mediated neurodegeneration via blocking receptor-mediated excitotoxicity have failed in clinical trials. We introduce the concept that under hypoglycemic conditions extracellular Glu can be transformed from a neurotoxin to a survival factor by GOT, provided there is sufficient oxygen to sustain cellular respiration.
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Affiliation(s)
- Cameron Rink
- Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio 43210, USA
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Zhang M, Lee SJ, An C, Xu JF, Joshi B, Nabi IR, Choi AM, Jin Y. Caveolin-1 mediates Fas-BID signaling in hyperoxia-induced apoptosis. Free Radic Biol Med 2011; 50:1252-62. [PMID: 21382479 PMCID: PMC4134776 DOI: 10.1016/j.freeradbiomed.2011.02.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 02/23/2011] [Accepted: 02/25/2011] [Indexed: 12/15/2022]
Abstract
Fas-mediated apoptosis is a crucial cellular event. Fas, the Fas-associated death domain, and caspase 8 form the death-inducing signaling complex (DISC). Activated caspase 8 mediates the extrinsic pathways and cleaves cytosolic BID. Truncated BID (tBID) translocates to the mitochondria, facilitates the release of cytochrome c, and activates the intrinsic pathways. However, the mechanism causing these DISC components to aggregate and form the complex remains unclear. We found that Cav-1 regulated Fas signaling and mediated the communication between extrinsic and intrinsic pathways. Shortly after hyperoxia (4 h), the colocalization and interaction of Cav-1 and Fas increased, followed by Fas multimer and DISC formation. Deletion of Cav-1 (Cav-1-/-) disrupted DISC formation. Further, Cav-1 interacted with BID. Mutation of Cav-1 Y14 tyrosine to phenylalanine (Y14F) disrupted the hyperoxia-induced interaction between BID and Cav-1 and subsequently yielded a decreased level of tBID and resistance to hyperoxia-induced apoptosis. The reactive oxygen species (ROS) scavenger N-acetylcysteine decreased the Cav-1-Fas interaction. Deletion of glutathione peroxidase-2 using siRNA aggravated the BID-Cav-1 interaction and tBID formation. Taken together, these results indicate that Cav-1 regulates hyperoxia/ROS-induced apoptosis through interactions with Fas and BID, probably via Fas palmitoylation and Cav-1 Y14 phosphorylation, respectively.
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Affiliation(s)
- Meng Zhang
- Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Seon-Jin Lee
- Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - ChangHyeok An
- Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jin-fu Xu
- Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bharat Joshi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ivan R. Nabi
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Augustine M.K. Choi
- Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Yang Jin
- Division of Pulmonary and Critical Care, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Corresponding author. (Y. Jin)
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Chen Y, Li X, Ye Q, Tian J, Jing R, Xie Z. Regulation of alpha1 Na/K-ATPase expression by cholesterol. J Biol Chem 2011; 286:15517-24. [PMID: 21362623 DOI: 10.1074/jbc.m110.204396] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have reported that α1 Na/K-ATPase regulates the trafficking of caveolin-1 and consequently alters cholesterol distribution in the plasma membrane. Here, we report the reciprocal regulation of α1 Na/K-ATPase by cholesterol. Acute exposure of LLC-PK1 cells to methyl β-cyclodextrin led to parallel decreases in cellular cholesterol and the expression of α1 Na/K-ATPase. Cholesterol repletion fully reversed the effect of methyl β-cyclodextrin. Moreover, inhibition of intracellular cholesterol trafficking to the plasma membrane by compound U18666A had the same effect on α1 Na/K-ATPase. Similarly, the expression of α1, but not α2 and α3, Na/K-ATPase was significantly reduced in the target organs of Niemann-Pick type C mice where the intracellular cholesterol trafficking is blocked. Mechanistically, decreases in the plasma membrane cholesterol activated Src kinase and stimulated the endocytosis and degradation of α1 Na/K-ATPase through Src- and ubiquitination-dependent pathways. Thus, the new findings, taken together with what we have already reported, revealed a previously unrecognized feed-forward mechanism by which cells can utilize the Src-dependent interplay among Na/K-ATPase, caveolin-1, and cholesterol to effectively alter the structure and function of the plasma membrane.
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Affiliation(s)
- Yiliang Chen
- Department of Physiology and Pharmacology, College of Medicine, University of Toledo, Toledo, Ohio 43614-2598, USA
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Han Y, Yuan N, Zhang SJ, Gao J, Shi Z, Zhou YB, Gao XY, Zhu GQ. c-Src in paraventricular nucleus modulates sympathetic activity and cardiac sympathetic afferent reflex in renovascular hypertensive rats. Pflugers Arch 2011; 461:437-46. [PMID: 21340460 DOI: 10.1007/s00424-011-0932-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 12/23/2010] [Accepted: 02/01/2011] [Indexed: 10/18/2022]
Abstract
Enhanced cardiac sympathetic afferent reflex (CSAR) contributes to sympathetic activation in renovascular hypertension. The study was to determine whether c-Src in paraventricular nucleus (PVN) is involved in the enhanced CSAR and sympathetic activation in hypertensive rats induced by two-kidney one-clip (2K1C). At the end of the fourth week after 2K1C surgery, renal sympathetic nerve activity (RSNA) was recorded in anesthetized rats with baroreceptor denervation and vagotomy. The CSAR was evaluated by the RSNA response to epicardial application of capsaicin. In the PVN, c-Src activity was higher in 2K1C rats than sham-operated (Sham) rats while c-Src expression was not. Epicardial application of capsaicin or PVN microinjection of angiotensin II (Ang II) increased c-Src activity more in 2K1C than Sham rats. PVN microinjection of selective Src family kinase inhibitor 4-Amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazol [3,4-D] pyrimidine (PP2) or 2,3-Dihydro-N,N-dimethyl-2-oxo-3-[(4,5,6,7-tetrahydro-1 H-indol-2-yl)methylene]-1 H-indole-5-sulfonamide (SU6656) abolished the CSAR and decreased RSNA more in 2K1C than Sham rats. The Ang II-induced RSNA and CSAR enhancement was abolished by PP2 or SU6656 pretreatment in 2K1C and Sham rats. NAD(P)H oxidase activity and superoxide anion level in PVN were higher in 2K1C rats, which was attenuated by PP2 but increased by epicardial application of capsaicin or PVN microinjection of Ang II. The effects of capsaicin or Ang II were abolished by PP2. These results indicate that c-Src in the PVN is involved in the enhanced CSAR and sympathetic activation in renovascular hypertension, and mediates the excitatory effects of Ang II in the PVN on the CSAR and sympathetic activity via NAD(P)H oxidase-derived generation of superoxide anions.
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Affiliation(s)
- Ying Han
- Department of Physiology, Nanjing Medical University, Nanjing, China
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Hamilton SK, Sims AL, Donavan J, Harth E. Non-viral siRNA delivery vectors: dendritic molecular transporter and molecular transporter nanovectors for target gene silencing. Polym Chem 2011. [DOI: 10.1039/c0py00342e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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The NMDA receptor NR1 subunit is critically involved in the regulation of NMDA receptor activity by C-terminal Src kinase (Csk). Neurochem Res 2010; 36:319-26. [PMID: 21113815 DOI: 10.1007/s11064-010-0330-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 11/15/2010] [Indexed: 01/25/2023]
Abstract
Previous studies have shown that Csk plays critical roles in the regulation of neural development, differentiation and glutamate-mediated synaptic plasticity. It has been found that Csk associates with the NR2A and 2B subunits of N-methyl-D-aspartate receptors (NMDARs) in a Src activity-dependent manner and serves as an intrinsic mechanism to provide a "brake" on the induction of long-term synaptic potentiation (LTP) mediated by NMDARs. In contrast to the NR2A and 2B subunits, no apparent tyrosine phosphorylation is found in the NR1 subunit of NMDARs. Here, we report that Csk can also associate with the NR1 subunit in a Src activity-dependent manner. The truncation of the NR1 subunit C-tail which contains only one tyrosine (Y837) significantly reduced the Csk association with the NR1-1a/NR2A receptor complex. Furthermore, we found that either the truncation of NR2A C-tail at aa 857 or the mutation of Y837 in the NR1-1a subunit to phenylalanine blocked the inhibition of NR1-1a/NR2A receptors induced by intracellular application of Csk. Thus, both the NR1 and NR2 subunits are required for the regulation of NMDAR activity by Csk.
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Aggarwal BB, Sundaram C, Prasad S, Kannappan R. Tocotrienols, the vitamin E of the 21st century: its potential against cancer and other chronic diseases. Biochem Pharmacol 2010; 80:1613-31. [PMID: 20696139 DOI: 10.1016/j.bcp.2010.07.043] [Citation(s) in RCA: 341] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 07/12/2010] [Accepted: 07/27/2010] [Indexed: 02/07/2023]
Abstract
Initially discovered in 1938 as a "fertility factor," vitamin E now refers to eight different isoforms that belong to two categories, four saturated analogues (α, β, γ, and δ) called tocopherols and four unsaturated analogues referred to as tocotrienols. While the tocopherols have been investigated extensively, little is known about the tocotrienols. Very limited studies suggest that both the molecular and therapeutic targets of the tocotrienols are distinct from those of the tocopherols. For instance, suppression of inflammatory transcription factor NF-κB, which is closely linked to tumorigenesis and inhibition of HMG-CoA reductase, mammalian DNA polymerases and certain protein tyrosine kinases, is unique to the tocotrienols. This review examines in detail the molecular targets of the tocotrienols and their roles in cancer, bone resorption, diabetes, and cardiovascular and neurological diseases at both preclinical and clinical levels. As disappointment with the therapeutic value of the tocopherols grows, the potential of these novel vitamin E analogues awaits further investigation.
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Affiliation(s)
- Bharat B Aggarwal
- Cytokine Research Laboratory, Department of Experimental Therapeutics, The University of Texas, M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Box 143, Houston, TX 77030, USA.
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Abstract
A growing body of research supports that members of the vitamin E family are not redundant with respect to their biological function. Palm oil derived from Elaeis guineensis represents the richest source of the lesser characterized vitamin E, alpha-tocotrienol. One of 8 naturally occurring and chemically distinct vitamin E analogs, alpha-tocotrienol possesses unique biological activity that is independent of its potent antioxidant capacity. Current developments in alpha-tocotrienol research demonstrate neuroprotective properties for the lipid-soluble vitamin in brain tissue rich in polyunsaturated fatty acids (PUFAs). Arachidonic acid (AA), one of the most abundant PUFAs of the central nervous system, is highly susceptible to oxidative metabolism under pathologic conditions. Cleaved from the membrane phospholipid bilayer by cytosolic phospholipase A(2), AA is metabolized by both enzymatic and nonenzymatic pathways. A number of neurodegenerative conditions in the human brain are associated with disturbed PUFA metabolism of AA, including acute ischemic stroke. Palm oil-derived alpha-tocotrienol at nanomolar concentrations has been shown to attenuate both enzymatic and nonenzymatic mediators of AA metabolism and neurodegeneration. On a concentration basis, this represents the most potent of all biological functions exhibited by any natural vitamin E molecule. Despite such therapeutic potential, the scientific literature on tocotrienols accounts for roughly 1% of the total literature on vitamin E, thus warranting further investment and investigation.
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Affiliation(s)
- Chandan K Sen
- Department of Surgery, The Ohio State University Medical Center, Columbus, Ohio, USA.
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Khanna S, Biswas S, Shang Y, Collard E, Azad A, Kauh C, Bhasker V, Gordillo GM, Sen CK, Roy S. Macrophage dysfunction impairs resolution of inflammation in the wounds of diabetic mice. PLoS One 2010; 5:e9539. [PMID: 20209061 PMCID: PMC2832020 DOI: 10.1371/journal.pone.0009539] [Citation(s) in RCA: 425] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 02/11/2010] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Chronic inflammation is a characteristic feature of diabetic cutaneous wounds. We sought to delineate novel mechanisms involved in the impairment of resolution of inflammation in diabetic cutaneous wounds. At the wound-site, efficient dead cell clearance (efferocytosis) is a pre-requisite for the timely resolution of inflammation and successful healing. METHODOLOGY/PRINCIPAL FINDINGS Macrophages isolated from wounds of diabetic mice showed significant impairment in efferocytosis. Impaired efferocytosis was associated with significantly higher burden of apoptotic cells in wound tissue as well as higher expression of pro-inflammatory and lower expression of anti-inflammatory cytokines. Observations related to apoptotic cell load at the wound site in mice were validated in the wound tissue of diabetic and non-diabetic patients. Forced Fas ligand driven elevation of apoptotic cell burden at the wound site augmented pro-inflammatory and attenuated anti-inflammatory cytokine response. Furthermore, successful efferocytosis switched wound macrophages from pro-inflammatory to an anti-inflammatory mode. CONCLUSIONS/SIGNIFICANCE Taken together, this study presents first evidence demonstrating that diabetic wounds suffer from dysfunctional macrophage efferocytosis resulting in increased apoptotic cell burden at the wound site. This burden, in turn, prolongs the inflammatory phase and complicates wound healing.
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Affiliation(s)
- Savita Khanna
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Sabyasachi Biswas
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Yingli Shang
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Eric Collard
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Ali Azad
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Courtney Kauh
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Vineet Bhasker
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Gayle M. Gordillo
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Chandan K. Sen
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
| | - Sashwati Roy
- Comprehensive Wound Center, Department of Surgery, Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, Ohio, United States of America
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48
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DAPK1 interaction with NMDA receptor NR2B subunits mediates brain damage in stroke. Cell 2010; 140:222-34. [PMID: 20141836 DOI: 10.1016/j.cell.2009.12.055] [Citation(s) in RCA: 381] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 10/16/2009] [Accepted: 12/29/2009] [Indexed: 11/20/2022]
Abstract
N-methyl-D-aspartate (NMDA) receptors constitute a major subtype of glutamate receptors at extrasynaptic sites that link multiple intracellular catabolic processes responsible for irreversible neuronal death. Here, we report that cerebral ischemia recruits death-associated protein kinase 1 (DAPK1) into the NMDA receptor NR2B protein complex in the cortex of adult mice. DAPK1 directly binds with the NMDA receptor NR2B C-terminal tail consisting of amino acid 1292-1304 (NR2B(CT)). A constitutively active DAPK1 phosphorylates NR2B subunit at Ser-1303 and in turn enhances the NR1/NR2B receptor channel conductance. Genetic deletion of DAPK1 or administration of NR2B(CT) that uncouples an activated DAPK1 from an NMDA receptor NR2B subunit in vivo in mice blocks injurious Ca(2+) influx through NMDA receptor channels at extrasynaptic sites and protects neurons against cerebral ischemic insults. Thus, DAPK1 physically and functionally interacts with the NMDA receptor NR2B subunit at extrasynaptic sites and this interaction acts as a central mediator for stroke damage.
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Adibhatla RM, Hatcher JF. Lipid oxidation and peroxidation in CNS health and disease: from molecular mechanisms to therapeutic opportunities. Antioxid Redox Signal 2010; 12:125-69. [PMID: 19624272 DOI: 10.1089/ars.2009.2668] [Citation(s) in RCA: 317] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reactive oxygen species (ROS) are produced at low levels in mammalian cells by various metabolic processes, such as oxidative phosphorylation by the mitochondrial respiratory chain, NAD(P)H oxidases, and arachidonic acid oxidative metabolism. To maintain physiological redox balance, cells have endogenous antioxidant defenses regulated at the transcriptional level by Nrf2/ARE. Oxidative stress results when ROS production exceeds the cell's ability to detoxify ROS. Overproduction of ROS damages cellular components, including lipids, leading to decline in physiological function and cell death. Reaction of ROS with lipids produces oxidized phospholipids, which give rise to 4-hydroxynonenal, 4-oxo-2-nonenal, and acrolein. The brain is susceptible to oxidative damage due to its high lipid content and oxygen consumption. Neurodegenerative diseases (AD, ALS, bipolar disorder, epilepsy, Friedreich's ataxia, HD, MS, NBIA, NPC, PD, peroxisomal disorders, schizophrenia, Wallerian degeneration, Zellweger syndrome) and CNS traumas (stroke, TBI, SCI) are problems of vast clinical importance. Free iron can react with H(2)O(2) via the Fenton reaction, a primary cause of lipid peroxidation, and may be of particular importance for these CNS injuries and disorders. Cholesterol is an important regulator of lipid organization and the precursor for neurosteroid biosynthesis. Atherosclerosis, the major risk factor for ischemic stroke, involves accumulation of oxidized LDL in the arteries, leading to foam cell formation and plaque development. This review will discuss the role of lipid oxidation/peroxidation in various CNS injuries/disorders.
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Affiliation(s)
- Rao Muralikrishna Adibhatla
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53792-3232, USA.
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50
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Khanna S, Parinandi NL, Kotha SR, Roy S, Rink C, Bibus D, Sen CK. Nanomolar vitamin E alpha-tocotrienol inhibits glutamate-induced activation of phospholipase A2 and causes neuroprotection. J Neurochem 2009; 112:1249-60. [PMID: 20028458 DOI: 10.1111/j.1471-4159.2009.06550.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Our previous works have elucidated that the 12-lipoxygenase pathway is directly implicated in glutamate-induced neural cell death, and that such that toxicity is prevented by nM concentrations of the natural vitamin E alpha-tocotrienol (TCT). In the current study we tested the hypothesis that phospholipase A(2) (PLA(2)) activity is sensitive to glutamate and mobilizes arachidonic acid (AA), a substrate for 12-lipoxygenase. Furthermore, we examined whether TCT regulates glutamate-inducible PLA(2) activity in neural cells. Glutamate challenge induced the release of [(3)H]AA from HT4 neural cells. Such response was attenuated by calcium chelators (EGTA and BAPTA), cytosolic PLA(2) (cPLA(2))-specific inhibitor (AACOCF(3)) as well as TCT at 250 nM. Glutamate also caused the elevation of free polyunsaturated fatty acid (AA and docosahexaenoic acid) levels and disappearance of phospholipid-esterified AA in neural cells. Furthermore, glutamate induced a time-dependent translocation and enhanced serine phosphorylation of cPLA(2) in the cells. These effects of glutamate on fatty acid levels and on cPLA(2) were significantly attenuated by nM TCT. The observations that AACOCF(3), transient knock-down of cPLA(2) as well as TCT significantly protected against the glutamate-induced death of neural cells implicate cPLA(2) as a TCT-sensitive mediator of glutamate induced neural cell death. This work presents first evidence recognizing glutamate-induced changes in cPLA(2) as a novel mechanism responsible for neuroprotection observed in response to nanomolar concentrations of TCT.
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Affiliation(s)
- Savita Khanna
- Department of Surgery, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH 43210, USA
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