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Li Y, Cheng L, Li B, Jiang S, Chen L, Shao Y. Transition-Metal-Free Thiolation Annulation of 2-Fluorophenylacetylene Derivatives: Expedient Synthesis of Benzo[b]thiophenes Using Na2S•9H2O. ChemistrySelect 2016. [DOI: 10.1002/slct.201600270] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yibiao Li
- School of Chemical & Environmental Engineering; Wuyi University; Jiangmen Guangdong Province 529020 China
| | - Liang Cheng
- School of Chemical & Environmental Engineering; Wuyi University; Jiangmen Guangdong Province 529020 China
| | - Bin Li
- School of Chemical & Environmental Engineering; Wuyi University; Jiangmen Guangdong Province 529020 China
| | - Shaohua Jiang
- School of Chemical & Environmental Engineering; Wuyi University; Jiangmen Guangdong Province 529020 China
| | - Lu Chen
- School of Chemical & Environmental Engineering; Wuyi University; Jiangmen Guangdong Province 529020 China
| | - Yan Shao
- School of Chemical & Environmental Engineering; Wuyi University; Jiangmen Guangdong Province 529020 China
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Jackson TC, Verrier JD, Drabek T, Janesko-Feldman K, Gillespie DG, Uray T, Dezfulian C, Clark RS, Bayir H, Jackson EK, Kochanek PM. Pharmacological inhibition of pleckstrin homology domain leucine-rich repeat protein phosphatase is neuroprotective: differential effects on astrocytes. J Pharmacol Exp Ther 2013; 347:516-28. [PMID: 24023368 DOI: 10.1124/jpet.113.206888] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pleckstrin homology domain and leucine-rich repeat protein phosphatase 1 (PHLPP1) inhibits protein kinase B (AKT) survival signaling in neurons. Small molecule pan-PHLPP inhibitors (selective for PHLPP1 and PHLPP2) may offer a translatable method to induce AKT neuroprotection. We tested several recently discovered PHLPP inhibitors (NSC117079 and NSC45586; benzoic acid, 5-[2-[4-[2-(2,4-diamino-5-methylphenyl)diazenyl]phenyl]diazenyl]-2-hydroxy-,sodium salt.) in rat cortical neurons and astrocytes and compared the biochemical response of these agents with short hairpin RNA (shRNA)-mediated PHLPP1 knockdown (KD). In neurons, both PHLPP1 KD and experimental PHLPP inhibitors activated AKT and ameliorated staurosporine (STS)-induced cell death. Unexpectedly, in astrocytes, both inhibitors blocked AKT activation, and NSC117079 reduced viability. Only PHLPP2 KD mimicked PHLPP inhibitors on astrocyte biochemistry. This suggests that these inhibitors could have possible detrimental effects on astrocytes by blocking novel PHLPP2-mediated prosurvival signaling mechanisms. Finally, because PHLPP1 levels are reportedly high in the hippocampus (a region prone to ischemic death), we characterized hippocampal changes in PHLPP and several AKT targeting prodeath phosphatases after cardiac arrest (CA)-induced brain injury. PHLPP1 levels increased in rat brains subjected to CA. None of the other AKT inhibitory phosphatases increased after global ischemia (i.e., PHLPP2, PTEN, PP2A, and PP1). Selective PHLPP1 inhibition (such as by shRNA KD) activates AKT survival signaling in neurons and astrocytes. Nonspecific PHLPP inhibition (by NSC117079 and NSC45586) only activates AKT in neurons. Taken together, these results suggest that selective PHLPP1 inhibitors should be developed and may yield optimal strategies to protect injured hippocampal neurons and astrocytes-namely from global brain ischemia.
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Affiliation(s)
- Travis C Jackson
- University of Pittsburgh School of Medicine, Department of Critical Care Medicine, Safar Center for Resuscitation Research (T.C.J., P.M.K., H.B., R.S.C, K.J.F., C.D., T.U.) and Department of Pharmacology and Chemical Biology (J.D.V., D.G.G., E.K.J.),University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; and Department of Anesthesiology, Presbyterian Hospital (T.D.), Pittsburgh, Pennsylvania
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Hamdi Y, Kaddour H, Vaudry D, Bahdoudi S, Douiri S, Leprince J, Castel H, Vaudry H, Tonon MC, Amri M, Masmoudi-Kouki O. The octadecaneuropeptide ODN protects astrocytes against hydrogen peroxide-induced apoptosis via a PKA/MAPK-dependent mechanism. PLoS One 2012; 7:e42498. [PMID: 22927932 PMCID: PMC3424241 DOI: 10.1371/journal.pone.0042498] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 07/06/2012] [Indexed: 12/18/2022] Open
Abstract
Astrocytes synthesize and release endozepines, a family of regulatory peptides, including the octadecaneuropeptide (ODN) an endogenous ligand of both central-type benzodiazepine (CBR) and metabotropic receptors. We have recently shown that ODN exerts a protective effect against hydrogen peroxide (H2O2)-induced oxidative stress in astrocytes. The purpose of the present study was to determine the type of receptor and the transduction pathways involved in the protective effect of ODN in cultured rat astrocytes. We have first observed a protective activity of ODN at very low concentrations that was abrogated by the metabotropic ODN receptor antagonist cyclo1–8[DLeu5]OP, but not by the CBR antagonist flumazenil. We have also found that the metabotropic ODN receptor is positively coupled to adenylyl cyclase in astrocytes and that the glioprotective action of ODN upon H2O2-induced astrocyte death is PKA- and MEK-dependent, but PLC/PKC-independent. Downstream of PKA, ODN induced ERK phosphorylation, which in turn activated the expression of the anti-apoptotic gene Bcl-2 and blocked the stimulation by H2O2 of the pro-apoptotic gene Bax. The effect of ODN on the Bax/Bcl-2 balance contributed to abolish the deleterious action of H2O2 on mitochondrial membrane integrity and caspase-3 activation. Finally, the inhibitory effect of ODN on caspase-3 activity was shown to be PKA and MEK-dependent. In conclusion, the present results demonstrate that the potent glioprotective action of ODN against oxidative stress involves the metabotropic ODN receptor coupled to the PKA/ERK-kinase pathway to inhibit caspase-3 activation.
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Affiliation(s)
- Yosra Hamdi
- Laboratory of Functional Neurophysiology and Pathology, Research Unit UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Hadhemi Kaddour
- Laboratory of Functional Neurophysiology and Pathology, Research Unit UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - David Vaudry
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, University of Rouen, Mont-Saint-Aignan, France
- International Associated Laboratory Samuel de Champlain, Mont-Saint-Aignan, France
- Regional Platform for Cell Imaging of Haute-Normandie (PRIMACEN), Institute for Medical Research and Innovation (IRIB), University of Rouen, Mont-Saint-Aignan, France
| | - Seyma Bahdoudi
- Laboratory of Functional Neurophysiology and Pathology, Research Unit UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Salma Douiri
- Laboratory of Functional Neurophysiology and Pathology, Research Unit UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Jérôme Leprince
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, University of Rouen, Mont-Saint-Aignan, France
- International Associated Laboratory Samuel de Champlain, Mont-Saint-Aignan, France
- Regional Platform for Cell Imaging of Haute-Normandie (PRIMACEN), Institute for Medical Research and Innovation (IRIB), University of Rouen, Mont-Saint-Aignan, France
| | - Helene Castel
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, University of Rouen, Mont-Saint-Aignan, France
| | - Hubert Vaudry
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, University of Rouen, Mont-Saint-Aignan, France
- International Associated Laboratory Samuel de Champlain, Mont-Saint-Aignan, France
- Regional Platform for Cell Imaging of Haute-Normandie (PRIMACEN), Institute for Medical Research and Innovation (IRIB), University of Rouen, Mont-Saint-Aignan, France
- * E-mail: (MA), (HV)
| | - Marie-Christine Tonon
- Inserm U982, Laboratory of Neuronal and Neuroendocrine Communication and Differentiation, University of Rouen, Mont-Saint-Aignan, France
| | - Mohamed Amri
- Laboratory of Functional Neurophysiology and Pathology, Research Unit UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
- * E-mail: (MA), (HV)
| | - Olfa Masmoudi-Kouki
- Laboratory of Functional Neurophysiology and Pathology, Research Unit UR/11ES09, Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
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Masmoudi-Kouki O, Douiri S, Hamdi Y, Kaddour H, Bahdoudi S, Vaudry D, Basille M, Leprince J, Fournier A, Vaudry H, Tonon MC, Amri M. Pituitary adenylate cyclase-activating polypeptide protects astroglial cells against oxidative stress-induced apoptosis. J Neurochem 2011; 117:403-11. [PMID: 21244427 DOI: 10.1111/j.1471-4159.2011.07185.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Oxidative stress, associated with a variety of disorders including neurodegenerative diseases, results from accumulation of reactive oxygen species (ROS). Oxidative stress is not only responsible for neuron apoptosis, but can also provoke astroglial cell death. Numerous studies indicate that pituitary adenylate cyclase-activating polypeptide (PACAP) promotes neuron survival, but nothing is known regarding the action of PACAP on astroglial cell survival. Thus, the purpose of the present study was to investigate the potential glioprotective effect of PACAP on H(2)O(2)-induced astrocyte death. Pre-treatment of cultured rat astrocytes with nanomolar concentrations of PACAP prevented cell death provoked by H(2)O(2) (300 μM), whereas vasoactive intestinal polypeptide was devoid of protective activity. The effect of PACAP on astroglial cell survival was abolished by the type 1 PACAP receptor antagonist, PACAP6-38. The protective action of PACAP was blocked by the protein kinase A inhibitor H89, the protein kinase C inhibitor chelerythrine and the mitogen-activated protein (MAP)-kinase kinase (MEK) inhibitor U0126. PACAP stimulated glutathione formation, and blocked H(2)O(2)-evoked ROS accumulation and glutathione content reduction. In addition, PACAP prevented the decrease of mitochondrial activity and caspase 3 activation induced by H(2)O(2). Taken together, these data indicate for the first time that PACAP, acting through type 1 PACAP receptor, exerts a potent protective effect against oxidative stress-induced astrocyte death. The anti-apoptotic activity of PACAP on astrocytes is mediated through the protein kinase A, protein kinase C and MAPK transduction pathways, and can be accounted for by inhibition of ROS-induced mitochondrial dysfunctions and caspase 3 activation.
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Affiliation(s)
- Olfa Masmoudi-Kouki
- Department of Biological Sciences, Faculty of Science of Tunis, University Tunis El Manar, Tunis, Tunisia
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Mori Y, Shiotani A, Saito K, Araki K, Ikeda K, Nakagawa M, Watabe K, Ogawa K. A Novel Drug Therapy for Recurrent Laryngeal Nerve Injury Using T-588. Laryngoscope 2007; 117:1313-8. [PMID: 17507828 DOI: 10.1097/mlg.0b013e31805f681f] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES/HYPOTHESIS We have previously shown that gene therapy using Insulin-like growth factor (IGF)-I, glial cell line-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF), or a combination of these trophic factors, is a treatment option for recurrent laryngeal nerve (RLN) palsy. However, there remain some difficulties preventing this option from becoming a common clinical therapy for RLN injury. Thus, we need to develop novel treatment option that overcomes the problems of gene therapy.R(-)-1-(benzothiophen-5-yl)-2-[2-N,N-diethylamino]ethoxy]ethanol hydrochloride (T-588), a synthetic compound, is known to have neuroprotective effects on neural cells. In the present study, the possibility of new drug treatments using T-588 for RLN injury was assessed using rat models. STUDY DESIGN Animal study. METHODS Animals were administered T-588 for 4 weeks. The neuroprotective effects of T-588 administration after vagal nerve avulsion and neurofunctional recovery after recurrent laryngeal nerve crush were studied using motoneuron cell counting, evaluation of choline acetyltransferase immunoreactivity, the electrophysiologic examination, and the re-mobilization of the vocal fold. RESULTS T-588 administration successfully prevented motoneuron loss and ameliorated the choline acetyltransferase immunoreactivity in the ipsilateral nucleus ambiguus after vagal nerve avulsion. Significant improvements of motor nerve conduction velocity of the RLN and vocal fold movement were observed in the treatment group when compared to controls. CONCLUSION These results indicate that oral administration of T-588 might be a promising therapeutic option in treating peripheral nerve injury.
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Affiliation(s)
- Yuko Mori
- Department of Otolaryngology-Head and Neck Surgery, Keio University School of Medicine, Shinjuku, Tokyo, Japan
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Watabe K, Hayashi Y, Kawazoe Y. Peripheral nerve avulsion injuries as experimental models for adult motoneuron degeneration. Neuropathology 2006; 25:371-80. [PMID: 16382788 DOI: 10.1111/j.1440-1789.2005.00609.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have used adult rat peripheral nerve avulsion models to evaluate the effects of neuroprotective molecules on motoneuron degeneration. The right facial nerves of adult Fischer 344 male rats were avulsed and adenoviral vectors encoding glial cell line-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), transforming growth factor-beta2 (TGFbeta2), and growth inhibitory factor (GIF) were injected into the facial canal. The treatment with the vectors significantly prevented the loss of lesioned facial motoneurons, improved choline acetyltransferase (ChAT) immunoreactivity and suppressed the induction of nitric oxide synthase activity in these neurons. In separate experiments, animals were orally administered a solution of a neuroprotective compound T-588 after avulsion. Both free oral administration and oral tube administration of T-588 improved the survival of injured motoneurons and ameliorated their ChAT immunoreactivity. These results indicate that the gene transfer of GDNF, BDNF, TGFbeta2, and GIF and oral administration of T-588 may prevent the degeneration of motoneurons in adult humans with motoneuron injury and motor neuron diseases.
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Affiliation(s)
- Kazuhiko Watabe
- Department of Molecular Neuropathology, Tokyo Metropolitan Institute for Neuroscience, 2-6, Musashidai, Fuchu, Tokyo 183-8526, Japan.
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Kimura T, Sugimori M, Llinás RR. Purkinje cell long-term depression is prevented by T-588, a neuroprotective compound that reduces cytosolic calcium release from intracellular stores. Proc Natl Acad Sci U S A 2005; 102:17160-5. [PMID: 16278299 PMCID: PMC1287999 DOI: 10.1073/pnas.0508190102] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Long-term depression (LTD) of the parallel-fiber (PF) Purkinje synapse induced by four different experimental paradigms could be prevented in rat cerebellar slices by T-588, a neuroprotective compound. The paradigms consisted of pairing PF activation with climbing-fiber activation, direct depolarization, glutamic iontophoretic depolarization, or caffeine. In all cases, LTD was determined by patch-clamp recording of PF excitatory postsynaptic currents at the Purkinje cell somata. T-588 at 1 muM prevented the triggering of LTD reversibly and did not generate LTD on its own. Two-photon calcium-sensitive dye imaging demonstrated that T-588 reduces intracellular calcium concentration ([Ca(2+)](i)) increase by blocking calcium release from intracellular stores. Because [Ca(2+)](i) increase has been widely shown to trigger LTD and glutamate excitotoxicity, we propose that LTD may act as a neuroprotective mechanism. As such, LTD would serve to decrease glutamatergic-receptor sensitivity to limit deleterious [Ca(2+)](i) increase rather than to act as a mechanism for cerebellar learning.
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Affiliation(s)
- Tatsuo Kimura
- Toyama Chemical Company, 2-4-1 Shimookui, Toyama 930-8508, Japan
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Koyama Y, Egawa H, Osakada M, Baba A, Matsuda T. Increase by FK960, a novel cognitive enhancer, in glial cell line-derived neurotrophic factor production in cultured rat astrocytes. Biochem Pharmacol 2004; 68:275-82. [PMID: 15193999 DOI: 10.1016/j.bcp.2004.03.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2004] [Accepted: 03/19/2004] [Indexed: 01/19/2023]
Abstract
We examined the effect of N-(4-acetyl-1-piperazinyl)-p-fluorobenzamide monohydrate (FK960), a novel anti-dementia drug, on neurotrophic factor production in cultured rat astrocytes. FK960 (100nM) increased mRNA and protein levels of glial cell line-derived neurotrophic factor (GDNF). FK960 did not affect mRNA levels of neurotrophic factors other than GDNF. The effect of FK960 was not affected by antagonists of dopamine and alpha7-nicotinic acetylcholine receptors. FK960 stimulated phosphorylation of mitogen-activated protein/extracellular signal-regulated kinase (ERK) without any effect on phosphoryolation of p38 and c-Jun N-terminal kinase. FK960 increased the levels of c-Fos and phosphorylation of cAMP responsive element binding protein (CREB). The effect of FK960 on c-Fos was inhibited by PD98059 (10microM), an ERK kinase inhibitor, and cycloheximide (1microg/ml), a transcription inhibitor, and the effect of FK960 on CREB phosphorylation was blocked by PD98059. The effect of FK960 on GDNF mRNA expression was attenuated by PD98059, curcumin (10microM), an activator protein-1 inhibitor, cycloheximide and actinomycin D (10microg/ml). These results suggest that FK960 stimulates GDNF production in c-Fos- and CREB-dependent mechanisms in cultured astrocytes and that ERK signal is responsible for both c-Fos expression and CREB phosphorylation in the cascades.
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Affiliation(s)
- Yutaka Koyama
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan
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Iwasaki Y, Ichikawa Y, Igarashi O, Konno S, Aoyagi J, Ikeda K, Marabuchi S, Ono S, Iguchi H, Kawabe K, Fujioka T. T-588 protects motor neuron death following axotomy. Neurochem Res 2004; 29:403-6. [PMID: 15002737 DOI: 10.1023/b:nere.0000013744.57398.fd] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
R(-)-1-(benzo [b] thiophen-5-yl)-2-[2-(N,N-diethylamino)ethoxy] ethanol hydrochloride) (T-588) enhances acetylcholine release. This compound slows the motor deterioration of wobbler mouse motor neuron disease and enhances neurite outgrowth and choline acetyltransferase activity in cultured rat spinal motor neurons. We examined the ability of T-588 on axotomized spinal motor neuron death in the rat spinal cord. After the postnatal unilateral section of sciatic nerve, there was approximately a 50% survival of motor neurons in the fourth lumbar segment. In comparison with vehicle, intraperitoneal injection of T-588 for 14 consecutive days rescued spinal motor neuron death. Our results showing in vivo neurotrophic activity of T-588 for motor neurons support the applicability of T-588 for the treatment of motor neuron diseases, such as amyotrophic lateral sclerosis and motor neuropathies.
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Affiliation(s)
- Yasuo Iwasaki
- Department of Neurology, Toho University Omori Hospital, Omori Ota-ku, Tokyo, Japan.
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Yamamuro A, Ago Y, Takuma K, Maeda S, Sakai Y, Baba A, Matsuda T. Possible involvement of astrocytes in neuroprotection by the cognitive enhancer T-588. Neurochem Res 2004; 28:1779-83. [PMID: 14649717 DOI: 10.1023/a:1026103304490] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have previously shown that the cognition enhancer (1R)-1-benzo[b]thiophen-5-yl-2-[2-(diethylamino)ethoxy]ethan-1-ol hydrochloride (T-588) protects astrocytes against hydrogen peroxide (H2O2) injury via activation of extracellular signal-regulated kinase (ERK) pathway. The present study examines whether the effect of T-588 on astrocytes contributes to neuroprotection in neuronal injury models. Astrocyte-conditioned medium (ACM) protected against neuronal injury induced by amyloid-beta protein (A beta) in cultured cortical neurons. The effect of ACM on A beta-induced injury was blocked by the ERK kinase inhibitor 2'-amino-3'-methoxyflavone. ACM stimulated ERK phosphorylation in cultured neurons. ACM derived from astrocytes exposed to H2O2 lost the activities to stimulate ERK phosphorylation and protect against neuronal injury. T-588 blocked the H2O2-induced loss of the activities of ACM. These results suggest that ACM protects against neuronal injury by an ERK-dependent mechanism, and the effect of T-588 on astrocytic injury results in neuroprotection.
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Affiliation(s)
- Akiko Yamamuro
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan
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Takuma K, Baba A, Matsuda T. Astrocyte apoptosis: implications for neuroprotection. Prog Neurobiol 2004; 72:111-27. [PMID: 15063528 DOI: 10.1016/j.pneurobio.2004.02.001] [Citation(s) in RCA: 350] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Accepted: 02/04/2004] [Indexed: 12/21/2022]
Abstract
Astrocytes, the most abundant glial cell types in the brain, provide metabolic and trophic support to neurons and modulate synaptic activity. Accordingly, impairment in these astrocyte functions can critically influence neuronal survival. Recent studies show that astrocyte apoptosis may contribute to pathogenesis of many acute and chronic neurodegenerative disorders, such as cerebral ischemia, Alzheimer's disease and Parkinson's disease. We found that incubation of cultured rat astrocytes in a Ca(2+)-containing medium after exposure to a Ca(2+)-free medium causes an increase in intracellular Ca(2+) concentration followed by apoptosis, and that NF-kappa B, reactive oxygen species, and enzymes such as calpain, xanthine oxidase, calcineurin and caspase-3 are involved in reperfusion-induced apoptosis. Furthermore, we demonstrated that heat shock protein, mitogen-activated protein/extracellular signal-regulated kinase, phosphatidylinositol-3 kinase and cyclic GMP phosphodiesterase are target molecules for anti-apoptotic drugs. This review summarizes (1) astrocytic functions in neuroprotection, (2) current evidence of astrocyte apoptosis in both in vitro and in vivo studies including its molecular pathways such as Ca(2+) overload, oxidative stress, NF-kappa B activation, mitochondrial dysfunction, endoplasmic reticulum stress, and protease activation, and (3) several drugs preventing astrocyte apoptosis. As a whole, this article provides new insights into the potential role of astrocytes as targets for neuroprotection. In addition, the advance in the knowledge of molecular mechanisms of astrocyte apoptosis may lead to the development of novel therapeutic strategies for neurodegenerative disorders.
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Affiliation(s)
- Kazuhiro Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Kobe 651-2180, Japan
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Phuagphong P, Fukushima T, Hatanaka R, Tanaka K, Baba A, Matsuda T. T-588, a Cognitive Enhancer, Protects Against Sodium Nitroprusside-Induced Toxicity in Cultured Astrocytes. J Pharmacol Sci 2004; 95:135-8. [PMID: 15153661 DOI: 10.1254/jphs.95.135] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The effects of (1R)-1-benzo[b]thiophen-5-yl-2-[2-(diethylamino)ethoxy]ethan-1-ol hydrochloride (T-588), a cognitive enhancer, on sodium nitroprusside (SNP)-induced cytotoxicity were examined in cultured rat astrocytes. Treatment with 100 microM SNP for 72 h decreased cell viability and mitochondrial function assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenil tetrazolium bromide (MTT) reduction activity, mitochondrial transmembrane potential, and intracellular ATP level. T-588 at 100 microM prevented SNP-induced mitochondrial dysfunction and cell injury. Furthermore, T-588 increased MTT reduction activity without affecting cell proliferation in astrocytes. These results suggest that T-588 has a protective effect against SNP-mediated toxicity via improvement of mitochondrial dysfunction in astrocytes.
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Affiliation(s)
- Patamawan Phuagphong
- Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan
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Iwasaki Y, Ichikawa Y, Igarasi O, Aoyagi J, Konno S, Ikeda K, Iguchi H, Kawabe S, Marubuchi S, Ono S. T-588 protects motor neuron death against glutamate-induced neurotoxicity. Neurochem Res 2003; 28:1829-32. [PMID: 14649724 DOI: 10.1023/a:1026167624054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
To examine the possible neuroprotective effect of T-588 against glutamate-induced neurotoxicity, we analyzed the pharmacological utility of T-588 in a postnatal organotypic culture model of motor neuron degeneration. Treatment with 10(-5) M of glutamate resulted a motor neuron loss and decreased activity of choline acetyltransferase (ChAT). Cotreatment of 10(-5) M of glutamate and T-588 revealed a protective effect against motor neuron death and decreased ChAT activity. We concluded that T-588 may play important roles in the survival and maintenance of spinal motor neurons in its neuroprotection against glutamate-induced neurotoxicity. Our data may provide a rationale for designing a therapeutic strategy for protection against pathologically induced motor neuron damage or cell death such as amyotrophic lateral sclerosis and motor neuropathy.
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Affiliation(s)
- Yasuo Iwasaki
- Department of Neurology, Toho University Omori Hospital, Tokyo, Japan.
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Yokoyama I, Sakai Y, Hatayama Y, Tsuji S, Koyama Y, Baba A, Matsuda T. T-588, a cognitive enhancer, stimulates in vivo phosphorylation of extracellular signal-regulated kinases in the hippocampus. BRAIN RESEARCH. COGNITIVE BRAIN RESEARCH 2003; 17:522-5. [PMID: 12880921 DOI: 10.1016/s0926-6410(03)00142-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Administration of (1R)-1-benzo[b]thiophen-5-yl-2-[2-(diethylamino)ethoxy]ethan-1-ol hydrochloride (T-588), a cognitive enhancer, like the acetylcholine esterase inhibitors physostigmine and tacrine, stimulated phosphorylation of extracellular signal-regulated kinases (ERK) in the mouse hippocampus. The effect of T-588 on ERK phosphorylation was persistent from 2 to 6 h after injection. Immunohistochemical study showed that T-588 stimulated neuronal ERK phosphorylation in rat hippocampal CA1 pyramidal subfield. These findings suggest that systemic T-588 stimulates the ERK kinase pathway in the hippocampal neurons.
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Affiliation(s)
- Ikuko Yokoyama
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
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Yamamuro A, Ago Y, Maeda S, Sakai Y, Baba A, Matsuda T. Protective effect of T-588 on toxic damage by serum deprivation and amyloid-beta protein in cultured neurons. J Pharmacol Sci 2003; 92:153-6. [PMID: 12832844 DOI: 10.1254/jphs.92.153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The present study examines the effect of the cognition enhancer (1R)-1-benzo[b]thiophen-5-yl-2-[2-(diethylamino)ethoxy]ethan-1-ol hydrochloride (T-588) on neuronal injury induced by serum deprivation or amyloid-beta protein (A beta). T-588 protected partially against neuronal injury induced by serum deprivation or A beta in cultured cortical neurons. T-588 did not affect the phosphorylation of extracellular signal-regulated kinase (ERK) in cortical neurons and SH-SY5Y cells. These results suggest that T-588 has a protective effect in neuronal injury models and the effect is not mediated by an ERK signal pathway.
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Affiliation(s)
- Akiko Yamamuro
- Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University
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Takuma K, Kiriu M, Mori K, Lee E, Enomoto R, Baba A, Matsuda T. Roles of cathepsins in reperfusion-induced apoptosis in cultured astrocytes. Neurochem Int 2003; 42:153-9. [PMID: 12421595 DOI: 10.1016/s0197-0186(02)00077-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Astrocytic apoptosis may play a role in the central nervous system injury. We previously showed that reperfusion of cultured astrocytes with normal medium after exposure to hydrogen peroxide (H(2)O(2))-containing medium causes apoptosis. This study examines the involvement of the lysosomal enzymes cathepsins B and D in the astrocytic apoptosis. Reperfusion after exposure to H(2)O(2) caused a marked increase in caspase-3 and cathepsin D activities and a marked decrease in cathepsin B activity. Pepstatin A, an inhibitor of cathepsin D, and acetyl-L-aspartyl-L-methionyl-L-glutaminyl-L-aspart-1-aldehyde (Ac-DMQD-CHO), a specific inhibitor of caspase-3, blocked the H(2)O(2)-induced decrease in cell viability and DNA ladder formation in cultured rat astrocytes. The (L-3-trans-(propylcarbamoyl)oxirane-2-carbonyl)-L-isoleucyl-L-proline methyl ester (CA074 Me), a specific inhibitor of cathepsin B, did not affect the H(2)O(2)-induced cell injury. On the other hand, CA074 Me decreased cell viability with DNA ladder formation when cultured in the presence of Ac-DMQD-CHO. This caspase-independent apoptosis was attenuated by the addition of the cathepsin D inhibitor pepstatin A. Caspase-3 like activity was markedly inhibited by Ac-DMQD-CHO and partially by pepstatin A. Pepstatin A and CA074 Me inhibited cathepsin B and cathepsin D activities, respectively, in the presence and absence of Ac-DMQD-CHO. These results suggest that cathepsins B and D are involved in astrocytic apoptosis: cathepsin D acts as a death-inducing factor upstream of caspase-3 and the caspase-independent apoptosis is regulated antagonistically by cathepsins B and D.
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Affiliation(s)
- Kazuhiro Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, High Technology Research Center, Kobe Gakuin University, Kobe 651-2180, Japan
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Fauconneau B, Petegnief V, Sanfeliu C, Piriou A, Planas AM. Induction of heat shock proteins (HSPs) by sodium arsenite in cultured astrocytes and reduction of hydrogen peroxide-induced cell death. J Neurochem 2002; 83:1338-48. [PMID: 12472888 DOI: 10.1046/j.1471-4159.2002.01230.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Induction of heat shock proteins (HSPs) protects cells from oxidative injury. Here Hsp72, Hsp27 and heme oxygenase-1 (HO-1) were induced in cultured rat astrocytes, and protection against oxidative stress was investigated. Astrocytes were treated with sodium arsenite (20-50 micro m) for 1 h, which was non-toxic to cells, 24 h later they were exposed to 400 micro m H2O2 for 1 h, and cell death was evaluated at different time points. Arsenite triggered strong induction of HSPs, which was prevented by 1 micro g/mL cycloheximide (CXH). H2O2 caused cell loss and increased cell death with features of apoptosis, i.e. TdT-mediated dUTP nick-end labelling (TUNEL) reaction and caspase-3 activation. These features were abrogated by pre-treatment with arsenite, which prevented cell loss and significantly reduced the number of dead cells. The protective effect of arsenite was not detected in the presence of CHX. Pre-treatment with arsenite increased protein kinase B (Akt) and extracellular signal regulated kinase 1/2 (ERK1/2) phosphorylation after H2O2. However, while Akt phosphorylation was prevented by CHX, Erk1/2 phosphorylation was further enhanced by CHX. The results show that transient arsenite pre-treatment induces Hsp72, HO-1 and, to a lesser extent, Hsp27; it reduces H2O2-induced astrocyte death; and it causes selective activation of Akt following H2O2. It is suggested that HSP expression at the time of H2O2 exposure protects astrocytes from oxidative injury and apoptotic cell death by means of pro-survival Akt.
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Affiliation(s)
- Bernard Fauconneau
- Departament de Farmacologia i Toxicologia, IIBB-CSIC, IDIBAPS, Barcelona, Spain
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Gabryel B, Adamczyk J, Huzarska M, Pudełko A, Trzeciak HI. Aniracetam attenuates apoptosis of astrocytes subjected to simulated ischemia in vitro. Neurotoxicology 2002; 23:385-95. [PMID: 12387365 DOI: 10.1016/s0161-813x(02)00084-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of the present study was to establish whether aniracetam is capable of protecting cultured rat astrocytes against ischemic injury. Treatment of the cultures with aniracetam (1, 10 and 100 mM) during 24 h ischemia simulated in vitro significantly decreased the number of apoptotic cells. The antiapoptotic effects of the drug were confirmed by the increase of intracellular ATP and phosphocreatine (PCr) levels and the inhibition of the caspase-3 activity. Aniracetam also attenuated cellular oxidative stress by decreased production of reactive oxygen species (ROS). These effects were associated with the decrease in levels of c-fos and c-jun mRNA in primary astrocyte cultures exposed to 24 h ischemia. When cultured astrocytes were incubated during 24 h simulated ischemia with wortmannin, a phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor or PD98059, a mitogen-activated protein (MAP)/extracellular signal regulated kinase (ERK) (MEK) inhibitor the cell apoptosis was accelerated. This effect was antagonized by adding 100 mM aniracetam to the culture medium. These findings suggest that the protective effect of aniracetam is mediated by PI 3-kinase and MEK pathways in the downstream mechanisms.
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Affiliation(s)
- Bozena Gabryel
- Department of Pharmacology, Silesian Medical University, Katowice, Poland.
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Takuma K, Mori K, Lee E, Enomoto R, Baba A, Matsuda T. Heat shock inhibits hydrogen peroxide-induced apoptosis in cultured astrocytes. Brain Res 2002; 946:232-8. [PMID: 12137926 DOI: 10.1016/s0006-8993(02)02888-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Heat shock proteins (HSPs) have been shown to act as inhibitors of apoptosis, but this anti-apoptotic effect is not known in the central nervous system. Prior heat shock has been demonstrated to protect astrocytes from cell death in a model of reperfusion injury (Brain Res. 735 (1996) 265). The present study examines the mechanism underlying the protective effect of the heat shock. Preincubation of astrocytes at 40 degrees C for 10 min attenuated the hydrogen peroxide (H(2)O(2))-induced decrease in cell viability, DNA ladder formation and nuclear condensation, and these effects were blocked by the protein synthesis inhibitor cycloheximide. The thermal stress inhibited the H(2)O(2)-induced increase in caspase-3 like protease activity, but it did not affect the H(2)O(2)-induced loss of mitochondrial membrane potential. The cytosol prepared from preheated cells did not affect Ca(2+)-induced swelling of mitochondria, a marker of the permeable transition pore. The protective effect of the thermal stress on the H(2)O(2)-induced decrease in cell viability was not affected by the mitogen-activated protein/extracellular signal-regulated kinase kinase inhibitor 2'-amino-3'-methoxyflavone, the phosphatidylinositol-3 kinase inhibitor wortmannin and the NF-kappaB inhibitor pyrrolidinedithiocarbamate. These findings suggest that HSPs inhibit apoptosis via an inhibition of caspase-3 activation without effect on mitochondrial dysfunction.
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Affiliation(s)
- Kazuhiro Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Japan
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Fujita T, Meguro T, Fukuyama R, Nakamuta H, Koida M. New signaling pathway for parathyroid hormone and cyclic AMP action on extracellular-regulated kinase and cell proliferation in bone cells. Checkpoint of modulation by cyclic AMP. J Biol Chem 2002; 277:22191-200. [PMID: 11956184 DOI: 10.1074/jbc.m110364200] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
cAMP signaling, activated by extracellular stimuli such as parathyroid hormone, has cell type-specific effects important for cellular proliferation and differentiation in bone cells. Recent evidence of a second enzyme target for cAMP suggests divergent effects on extracellular-regulated kinase (ERK) activity depending on Epac/Rap1/B-Raf signaling. We investigated the molecular mechanism of the dual functionality of cAMP on cell proliferation in clonal bone cell types. MC3T3-E1 and ATDC5, but not MG63, express a 95-kDa isoform of B-Raf. cAMP stimulated Ras-independent and Rap1-dependent ERK phosphorylation and cell proliferation in B-Raf-expressing cells, but inhibited growth in B-Raf-lacking cells. The mitogenic action of cAMP was blocked by the ERK pathway inhibitor PD98059. In B-Raf-transduced MG63 cells, cAMP stimulated ERK activation and cell proliferation. Thus, B-Raf is the dominant molecular switch that permits differential cAMP-dependent regulation of ERK with important implications for cell proliferation in bone cells. These findings might explain the dual functionality of parathyroid hormone on osteoblastic cell proliferation.
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Affiliation(s)
- Takashi Fujita
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Japan 573-0101. t-fujita@pharm,setsunan
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Takuma K, Phuagphong P, Lee E, Enomoto R, Mori K, Baba A, Matsuda T. The nitric oxide donor NOC12 protects cultured astrocytes against apoptosis via a cGMP-dependent mechanism. JAPANESE JOURNAL OF PHARMACOLOGY 2002; 89:64-71. [PMID: 12083744 DOI: 10.1254/jjp.89.64] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
We examined the effect of 3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC12), a nitric oxide (NO) donor, on apoptosis in cultured astrocytes. Reperfusion after hydrogen peroxide (H2O2) exposure caused a decrease in cell viability, loss of mitochondrial membrane potential, caspase-3 activation, DNA ladder formation, and nuclear condensation. NOC12 at 10-100 microM significantly attenuated these apoptotic changes, while the NO donor at 1 mM caused cell injury and exacerbated the H202-induced cell injury. NOC12 increased intracellular cGMP levels in a dose dependent manner with the maximal effect at 100 microM. The protective effect of NOC12 was mimicked by the NO-independent guanylate cyclase activator 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole, and was attenuated by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and the cGMP-dependent protein kinase inhibitor KT5823. ODQ and KT5823 did not block but rather exacerbated the cytotoxic effect of NOC12 at 1 mM. These findings demonstrate that lower concentrations of NOC12 inhibit the H2O2-induced apoptosis of astrocytes in a cGMP-dependent way, but higher concentrations of NOC12 show a toxic effect on astrocytes in a cGMP-independent way.
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Affiliation(s)
- Kazuhiro Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Kobe, Japan
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Iwasaki Y, Ikeda K, Ichikawa Y, Igarashi O, Kinoshita M, Marubuchi S, Ono S. T-588 enhances neurite outgrowth and choline acetyltransferase in cultured rat spinal ventral horn neurons. Neurochem Res 2002; 27:225-8. [PMID: 11958520 DOI: 10.1023/a:1014884504879] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
T-588(R(-)-1-(benzo(b)thiophen-5yl)-2-[2(N,N-diethylamino)ethoxy]ethanol hydrochloride) is a novel compound which has been shown to exhibit a wide range of neurotrophic effects both in vivo and in vitro. This compound can slow the motor deterioration of wobbler mouse motor neuron disease. However, it is not known whether this compound has a trophic effect on spinal motor neurons. We have studied the effect of T-588 on neurite outgrowth and choline acetyltransferase(ChAT) activity in primary explant cultures of ventral spinal cord of fetal rats(VSCC). Cultures were treated with T-588 from day 1 to 1 week. T-588 treated VSCC, compared with control VSCC, had a significant neurite promoting effect at ranged between 10(-8) molar(M) and 10(-5) M, with 2.3 to 5.3 fold increased over that of control VSCC. In T-588 treated VSCC, ChAT activity was increased 1.5 times over that of control at 10(-6), and 10(-5) M respectively. Our data showing T-588 has neurotrophic action on VSCC and suggests a potential use of T-588 in treating diseases that involve degeneration and death of spinal motor neurons, such as motor neuropathy and motor neuron disease.
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Affiliation(s)
- Yasuo Iwasaki
- Fourth Department of Internal Medicine, Toho University Ohashi Hospital, Tokyo, Japan.
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Takuma K, Phuagphong P, Lee E, Mori K, Baba A, Matsuda T. Anti-apoptotic effect of cGMP in cultured astrocytes: inhibition by cGMP-dependent protein kinase of mitochondrial permeable transition pore. J Biol Chem 2001; 276:48093-9. [PMID: 11677240 DOI: 10.1074/jbc.m108622200] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Reperfusion of cultured astrocytes with normal medium after exposure to H(2)O(2)-containing medium causes apoptosis. We have recently shown that ibudilast, which has been used for bronchial asthma and cerebrovascular disorders, attenuated the H(2)O(2)-induced apoptosis of astrocytes via the cGMP signaling pathway. This study examines the mechanism underlying the protective effect of cGMP. The membrane-permeable cGMP analog dibutyryl-cGMP attenuated the H(2)O(2)-induced decrease in cell viability, DNA ladder formation, nuclear condensation, reduction of the mitochondrial membrane potential, cytochrome c release from mitochondria, and caspase-3 activation in cultured astrocytes. These effects of dibutyryl-cGMP were almost completely inhibited by the cGMP-dependent protein kinase (PKG) inhibitor KT5823. In isolated rat brain mitochondria, cGMP in the presence of cytosolic extract from astrocytes inhibited the mitochondrial permeability transition pore (PTP) as determined by monitoring Ca(2+)-induced mitochondrial swelling. This ability of the cytosolic extract was inactivated by heat treatment and was mimicked by exogenous PKG. The effect of cGMP on the mitochondrial swelling was blocked by KT5823. The PTP inhibitors cyclosporin A and bongkrekic acid prevented the H(2)O(2)-induced decrease in cell viability and caspase-3 activation. These findings demonstrate that cGMP inhibits the mitochondrial PTP via the activation of PKG, and the prevention of mitochondrial dysfunction contributes to its anti-apoptotic effect.
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Affiliation(s)
- K Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Kobe 651-2180 Japan
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Abstract
Astrocytes, the most abundant glial cell type in the brain, are considered to have physiological and pathological roles in neuronal activities. We found that reperfusion of cultured astrocytes after Ca2+ depletion causes Ca2+ overload followed by delayed cell death and the Na(+)-Ca2+ exchanger in the reverse mode is responsible for this Ca(2+)-mediated cell injury (Ca2+ paradox injury). The Ca2+ paradox injury of cultured astrocytes is considered to be an in vitro model of ischemia/reperfusion injury, since a similar paradoxical change in extracellular Ca2+ concentration is reported in ischemic brain tissue. This review summarizes the mechanisms underlying the Ca(2+)-mediated injury of astrocytes and the protective effects of drugs against Ca2+ reperfusion injury. This study shows that Ca2+ reperfusion injury of astrocytes is accompanied by apoptosis as evidenced by DNA fragmentation and nuclear condensation. Calpain, reactive oxygen species, calcineurin, caspase-3, and NF-kappa B are involved in Ca2+ reperfusion-induced delayed apoptosis of astrocytes. Several drugs including CV-2619, T-588 and ibudilast protect astrocytes against the delayed apoptosis. CV-2619 prevents astrocytes from the delayed apoptosis by production of nerve growth factor, resulting in an activation of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) and phosphatidylinositol-3 (PI3) kinase signal pathways. The protective effect of T-588 is mainly mediated by an activation of MAP/ERK signal cascade. Moreover, ibudilast prevents the Ca2+ reperfusion-induced delayed apoptosis of astrocytes via cyclic GMP signaling pathway. Further studies in this system will contribute to the development of new drugs that attenuate ischemia/reperfusion injury via modulation of astrocytes.
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Affiliation(s)
- K Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180, Japan
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Takuma K, Lee E, Enomoto R, Mori K, Baba A, Matsuda T. Ibudilast attenuates astrocyte apoptosis via cyclic GMP signalling pathway in an in vitro reperfusion model. Br J Pharmacol 2001; 133:841-8. [PMID: 11454657 PMCID: PMC1572853 DOI: 10.1038/sj.bjp.0704146] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We examined the effect of 3-isobutyryl-2-isopropylpyrazolo[1,5-a]pyridine (ibudilast), which has been clinically used for bronchial asthma and cerebrovascular disorders, on cell viability induced in a model of reperfusion injury. Ibudilast at 10 - 100 microM significantly attenuated the H(2)O(2)-induced decrease in cell viability. Ibudilast inhibited the H(2)O(2)-induced cytochrome c release, caspase-3 activation, DNA ladder formation and nuclear condensation, suggesting its anti-apoptotic effect. Phosphodiesterase inhibitors such as theophylline, pentoxyfylline, vinpocetine, dipyridamole and zaprinast, which increased the guanosine-3',5'-cyclic monophosphate (cyclic GMP) level, and dibutyryl cyclic GMP attenuated the H(2)O(2)-induced injury in astrocytes. Ibudilast increased the cyclic GMP level in astrocytes. The cyclic GMP-dependent protein kinase inhibitor KT5823 blocked the protective effects of ibudilast and dipyridamole on the H(2)O(2)-induced decrease in cell viability, while the cyclic AMP-dependent protein kinase inhibitor KT5720, the cyclic AMP antagonist Rp-cyclic AMPS, the mitogen-activated protein/extracellular signal-regulated kinase inhibitor PD98059 and the leukotriene D(4) antagonist LY 171883 did not. KT5823 also blocked the effect of ibudilast on the H(2)O(2)-induced cytochrome c release and caspase-3-like protease activation. These findings suggest that ibudilast prevents the H(2)O(2)-induced delayed apoptosis of astrocytes via a cyclic GMP, but not cyclic AMP, signalling pathway.
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Affiliation(s)
- K Takuma
- Department of Analytical Chemistry, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe 651-2180 Japan
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Fujita T, Izumo N, Fukuyama R, Meguro T, Yasutomi C, Nakamuta H, Koida M. Incadronate and etidronate accelerate phosphate-primed mineralization of MC4 cells via ERK1/2-Cbfa1 signaling pathway in a Ras-independent manner: further involvement of mevalonate-pathway blockade for incadronate. JAPANESE JOURNAL OF PHARMACOLOGY 2001; 86:86-96. [PMID: 11430477 DOI: 10.1254/jjp.86.86] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Two types of bisphosphonates (BPs), incadronate (INC) and etidronate (ETI) accelerated phosphate (Pi)-primed mineralization of MC4 cells in a subnanomolar dose range. Intracellular signaling pathways involved were examined. 1) The effect of INC but not ETI was partially suppressed by two mevalonate (MVA) pathway metabolites, farnesylpyrophosphate (FPP) and geranylgeranylpyrophosphate (GGPP). 2) The BP-like accelerating effect was produced by statins and also by Toxin B, a Rho GTPases-specific inhibitor. 3) INC induced Cbfa1-nuclear localization within hours; and in an in vivo experiment using ovariectomized mice, its 3 weeks dosing exhibited the same effect in tibial extracts. 4) BPs promoted luciferase expression in murine p1.3-osteocalcin gene 2-luc and p6-osteoblast specific element 2-luc transfected cells, just as MVA, FPP and GGPP did independently and additively to INC. 5) BPs activated extracellular signal-regulated kinase (ERK1/2) in a Ras-independent manner within 5 min, and Pi was found to sensitize MC4 cells to BPs. MVA and its metabolites also activated ERKs but in a Ras-dependent manner and additively to INC. Ras dependency was determined using N17Ras-transfected cells. A MEK (MAP kinase-ERK kinase)-specific inhibitor PD98059 alone partly and with FPP completely blocked INC-induced mineralization. The results suggest that BPs act on Pi-sensitized MC4 cells to accelerate mineralization via nonRas-MEK-ERK1/2-Cbfa1 transactivation pathway and INC additionally acts by inhibiting the MVA pathway.
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Affiliation(s)
- T Fujita
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Japan
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Fujita T, Izumo N, Fukuyama R, Meguro T, Nakamuta H, Kohno T, Koida M. Phosphate provides an extracellular signal that drives nuclear export of Runx2/Cbfa1 in bone cells. Biochem Biophys Res Commun 2001; 280:348-52. [PMID: 11162521 DOI: 10.1006/bbrc.2000.4108] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inorganic phosphate (Pi) supplement is generally used to accelerate mineralization of cultured bone cells but the mechanism of action is totally unknown. How the action is related with the transactivation of Runx2/Cbfa1,a master gene product of bone formation,was examined. Clonal bone cells (osteoblastic MC3T3-E1, chondrocytic ATDC5 and osteocytic MLO-Y4) on preculture in ascorbate-containing medium constantly expressed and accumulated Cbfa1 in the nuclei, and subsequent increase of Pi concentration to 3 or 10 mM was found to invariably induce nuclear export (not import) of Cbfa1 which was completed in a few hours. In addition, Pi was found to lower the expression of osteocalcin. Leptomycin B completely inhibited Pi-induced nuclear export, suggesting that CRM1/exportin 1 is involved in Pi-induced nuclear export. The result suggests that bone cells are equipped with a novel Pi sensing mechanism which is functionally linked to a nuclear export system of Cbfa1.
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Affiliation(s)
- T Fujita
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka, Japan
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Takuma K, Yoshida T, Lee E, Mori K, Kishi T, Baba A, Matsuda T. CV-2619 protects cultured astrocytes against reperfusion injury via nerve growth factor production. Eur J Pharmacol 2000; 406:333-9. [PMID: 11040339 DOI: 10.1016/s0014-2999(00)00701-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this study, we examined the effect of the neuroprotective agent 2, 3-dimethoxy-5-methyl-6-(10-hydroxydecyl)-1,4-benzoquinone (CV-2619) on reperfusion injury in cultured rat astrocytes after exposure to hydrogen peroxide (H(2)O(2))-containing medium. CV-2619 (10 nM to 10 microM) significantly attenuated the reperfusion-induced decrease in cell viability. The compound showed an anti-apoptotic effect in this astrocyte injury model. Antioxidants such as ascorbic acid, alpha-tocopherol and reduced glutathione also inhibited H(2)O(2) exposure-induced cytotoxicity. CV-2619 did not affect the levels of reactive oxygen species, but it increased nerve growth factor (NGF) production. The effect of CV-2619 on H(2)O(2) exposure-induced cytotoxicity was blocked by cycloheximide and anti-NGF antibody. The protective effect of CV-2619 was antagonized by the mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase inhibitor 2'-amino-3'-methoxyflavone and the phosphatidylinositol-3 kinase inhibitor wortmannin. These findings suggest that the effect of CV-2619 is mediated at least partly by NGF production in astrocytes and that ERK and phosphatidylinositol-3 kinases play a role in the downstream mechanism.
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Affiliation(s)
- K Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, 651-2180, Kobe, Japan
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