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Abl2 Kinase Differentially Regulates iGluRs Current Activity and Synaptic Localization. Cell Mol Neurobiol 2023:10.1007/s10571-023-01317-9. [PMID: 36689065 DOI: 10.1007/s10571-023-01317-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 01/04/2023] [Indexed: 01/24/2023]
Abstract
Abelson non-receptor tyrosine kinases (Abl1 and Abl2) are established cellular signaling proteins, implicated in cytoskeletal reorganization essential for modulation of cell morphology and motility. During development of the central nervous system, Abl kinases play fundamental roles in neurulation and neurite outgrowth, relaying information from axon guidance cues and growth factor receptors to promote cytoskeletal rearrangements. In mature neurons, Abl kinases localize to pre- and postsynaptic compartments and are involved in regulation of synaptic stability and plasticity. Although emerging evidence indicates interchangeability of these isoforms in managing of cellular functions, in healthy adult neurons, Abl1 contribution is less elucidated, while Abl2 is required for optimal synaptic functioning. Our previous study demonstrated compartmentalization of Abl1 to the presynapse and Abl2 to the postsynapse and characterized their modulatory effect on spontaneous excitatory synaptic transmission. Here, we further delineate the role of Abl2 on regulation of the postsynaptic component of miniature excitatory postsynaptic current (mEPSC). Our findings show that both acute and prolonged activation of Abl2, in line with reduction of mEPSC amplitude, also decrease AMPA and NMDA current amplitudes. In contrast with the current-detrimental effect, prolonged Abl2 activity stabilizes spines, particularly contributing to maintenance of active synapses at distal (perhaps apical) segments of dendrites. Hence, we propose that attenuation of ion currents via ionotropic glutamatergic receptors by Abl2 kinase derives from either reduction of the receptor sensitivity for glutamate or is due to alteration of channel gating mechanisms. Abl2 and excitatory postsynapses: Abl2 expression level affects active excitatory synapse density on distal dendrites, while Abl2 activity impacts current density through AMPA and NMDA receptors.
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Rieg AD, Suleiman S, Anker C, Bünting NA, Verjans E, Spillner J, Kalverkamp S, von Stillfried S, Braunschweig T, Uhlig S, Martin C. Platelet-derived growth factor (PDGF)-BB regulates the airway tone via activation of MAP2K, thromboxane, actin polymerisation and Ca 2+-sensitisation. Respir Res 2022; 23:189. [PMID: 35841089 PMCID: PMC9287894 DOI: 10.1186/s12931-022-02101-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 06/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PDGFR-inhibition by the tyrosine kinase inhibitor (TKI) nintedanib attenuates the progress of idiopathic pulmonary fibrosis (IPF). However, the effects of PDGF-BB on the airway tone are almost unknown. We studied this issue and the mechanisms beyond, using isolated perfused lungs (IPL) of guinea pigs (GPs) and precision-cut lung slices (PCLS) of GPs and humans. METHODS IPL: PDGF-BB was perfused after or without pre-treatment with the TKI imatinib (perfused/nebulised) and its effects on the tidal volume (TV), the dynamic compliance (Cdyn) and the resistance were studied. PCLS (GP) The bronchoconstrictive effects of PDGF-BB and the mechanisms beyond were evaluated. PCLS (human): The bronchoconstrictive effects of PDGF-BB and the bronchorelaxant effects of imatinib were studied. All changes of the airway tone were measured by videomicroscopy and indicated as changes of the initial airway area. RESULTS PCLS (GP/human): PDGF-BB lead to a contraction of airways. IPL: PDGF-BB decreased TV and Cdyn, whereas the resistance did not increase significantly. In both models, inhibition of PDGFR-(β) (imatinib/SU6668) prevented the bronchoconstrictive effect of PDGF-BB. The mechanisms beyond PDGF-BB-induced bronchoconstriction include activation of MAP2K and TP-receptors, actin polymerisation and Ca2+-sensitisation, whereas the increase of Ca2+ itself and the activation of EP1-4-receptors were not of relevance. In addition, imatinib relaxed pre-constricted human airways. CONCLUSIONS PDGFR regulates the airway tone. In PCLS from GPs, this regulatory mechanism depends on the β-subunit. Hence, PDGFR-inhibition may not only represent a target to improve chronic airway disease such as IPF, but may also provide acute bronchodilation in asthma. Since asthma therapy uses topical application. This is even more relevant, as nebulisation of imatinib also appears to be effective.
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Affiliation(s)
- Annette D Rieg
- Department of Anaesthesiology, Medical Faculty RWTH-Aachen, Aachen, Germany.
| | - Said Suleiman
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Carolin Anker
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Nina A Bünting
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Eva Verjans
- Department of Paediatrics, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Jan Spillner
- Department of Cardiac and Thorax Surgery, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Sebastian Kalverkamp
- Department of Cardiac and Thorax Surgery, Medical Faculty RWTH-Aachen, Aachen, Germany
| | | | - Till Braunschweig
- Institute of Pathology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
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Reichenstein M, Borovok N, Sheinin A, Brider T, Michaelevski I. Abelson Kinases Mediate the Depression of Spontaneous Synaptic Activity Induced by Amyloid Beta 1-42 Peptides. Cell Mol Neurobiol 2021; 41:431-448. [PMID: 32399753 DOI: 10.1007/s10571-020-00858-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/27/2020] [Indexed: 10/24/2022]
Abstract
Amyloid beta (Aβ) peptides represent one of the most studied etiological factors of Alzheimer's disease. Nevertheless, the effects elicited by different molecular forms of amyloid beta peptides widely vary between the studies, mostly depending on experimental conditions. Despite the enormous amount of accumulated evidences concerning the pathological effects of amyloid beta peptides, the exact identity of the amyloid beta species is still controversial, and even less is clear as regards to the downstream effectors that mediate the devastating impact of these peptides on synapses in the central nervous system. Recent publications indicate that some of the neurotoxic effects of amyloid beta peptides may be mediated via the activation of proteins belonging to the Abelson non-receptor tyrosine kinase (Abl) family, that are known to regulate actin cytoskeleton structure as well as phosphorylate microtubule-associated tau protein, a hallmark of Alzheimer's disease. By performing series of miniature excitatory postsynaptic currents (mEPSC) recordings in cultured hippocampal cells, we demonstrate that activation of Abl kinases by acute application of 42 amino acid-length monomeric amyloid beta (Aβ1-42) peptides reduces spontaneous synaptic release, while this effect can be rescued by pharmacologic inhibition of Abl kinase activity, or by reduction of Abl expression with small interfering RNAs. Our electrophysiological data are further reinforced by a subsequent biochemical analysis, showing enhanced phosphorylation of Abl kinase substrate CT10 Regulator of Kinase-homolog-Like (Crkl) upon treatment of hippocampal neurons with Aβ peptides. Thus, we conclude that Abl kinase activation may be involved in Aβ-induced weakening of synaptic transmission.
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Affiliation(s)
- M Reichenstein
- Dept. of Biochemistry and Molecular Biology, Tel Aviv University, 69978, Tel Aviv, Israel
| | - N Borovok
- Dept. of Biochemistry and Molecular Biology, Tel Aviv University, 69978, Tel Aviv, Israel
| | - A Sheinin
- Dept. of Biochemistry and Molecular Biology, Tel Aviv University, 69978, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, 69978, Tel Aviv, Israel
| | - T Brider
- Department of Molecular Biology, Ariel University, 40700, Ariel, Israel
| | - I Michaelevski
- Department of Molecular Biology, Ariel University, 40700, Ariel, Israel.
- Integrative Brain Science Center Ariel, IBSCA, Ariel University, 40700, Ariel, Israel.
- The Adelson Medical School, Ariel University, 40700, Ariel, Israel.
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The Neuroprotective Effects of Astragaloside IV against H 2O 2-Induced Damage in SH-SY5Y Cells are Associated with Synaptic Plasticity. J CHEM-NY 2020. [DOI: 10.1155/2020/5343619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this study was to investigate whether the neuroprotective effects of astragaloside IV (AS-IV) against hydrogen peroxide (H2O2)-induced damage on human neuroblastoma cell line (SH-SY5Y) are associated with synaptic plasticity. The concentration screening of AS-IV and H2O2 on SH-SY5Y cells and the protective effects of AS-IV on SH-SY5Y cells under H2O2 stress were all determined by MTT assay. The expression of postsynaptic density 95 (PSD-95) and growth-associated protein 43 (GAP-43) were measured by western blot (WB) and inmunofluorescence staining assay under the same treatment conditions. According to the MTT results, the concentration of H2O2 at 50 μmol/L for 3 h was used for the cell damage model, and various concentrations of AS-IV (0.1, 0.2, 0.3, and 0.4 μmol/L) were used to affect SH-SY5Y cells. The MTT results showed that pretreatment of SH-SY5Y cells with AS-IV (0.1, 0.2, 0.3, and 0.4 μmol/L) attenuated the damage induced by H2O2 (50 μmol/L, 51.62% cell viability) and increased cell viability to 64.19, 63.48, 65.86, and 65.81%, respectively. Western blot analysis and immunofluorescence staining showed that the protective effects of AS-IV against SH-SY5Y cell damage caused by H2O2 resulted in reduced expression of PSD-95 and increased expression of GAP-43 in comparison with the H2O2 treatment group. The conclusion shows that AS-IV protected SH-SY5Y cells and enhanced their viability under H2O2 stress. AS-IV may facilitate presynaptic and postsynaptic plasticity to exert protective effects against oxidative damage of SH-SY5Y cells.
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Rieg AD, Suleiman S, Anker C, Verjans E, Rossaint R, Uhlig S, Martin C. PDGF-BB regulates the pulmonary vascular tone: impact of prostaglandins, calcium, MAPK- and PI3K/AKT/mTOR signalling and actin polymerisation in pulmonary veins of guinea pigs. Respir Res 2018; 19:120. [PMID: 29921306 PMCID: PMC6009037 DOI: 10.1186/s12931-018-0829-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/13/2018] [Indexed: 12/15/2022] Open
Abstract
Background Platelet-derived growth factor (PDGF)-BB and its receptor PDGFR are highly expressed in pulmonary hypertension (PH) and mediate proliferation. Recently, we showed that PDGF-BB contracts pulmonary veins (PVs) and that this contraction is prevented by inhibition of PDGFR-β (imatinib/SU6668). Here, we studied PDGF-BB-induced contraction and downstream-signalling in isolated perfused lungs (IPL) and precision-cut lung slices (PCLS) of guinea pigs (GPs). Methods In IPLs, PDGF-BB was perfused after or without pre-treatment with imatinib (perfused/nebulised), the effects on the pulmonary arterial pressure (PPA), the left atrial pressure (PLA) and the capillary pressure (Pcap) were studied and the precapillary (Rpre) and postcapillary resistance (Rpost) were calculated. Perfusate samples were analysed (ELISA) to detect the PDGF-BB-induced release of prostaglandin metabolites (TXA2/PGI2). In PCLS, the contractile effect of PDGF-BB was evaluated in pulmonary arteries (PAs) and PVs. In PVs, PDGF-BB-induced contraction was studied after inhibition of PDGFR-α/β, L-Type Ca2+-channels, ROCK/PKC, prostaglandin receptors, MAP2K, p38-MAPK, PI3K-α/γ, AKT/PKB, actin polymerisation, adenyl cyclase and NO. Changes of the vascular tone were measured by videomicroscopy. In PVs, intracellular cAMP was measured by ELISA. Results In IPLs, PDGF-BB increased PPA, Pcap and Rpost. In contrast, PDGF-BB had no effect if lungs were pre-treated with imatinib (perfused/nebulised). In PCLS, PDGF-BB significantly contracted PVs/PAs which was blocked by the PDGFR-β antagonist SU6668. In PVs, inhibition of actin polymerisation and inhibition of L-Type Ca2+-channels reduced PDGF-BB-induced contraction, whereas inhibition of ROCK/PKC had no effect. Blocking of EP1/3- and TP-receptors or inhibition of MAP2K-, p38-MAPK-, PI3K-α/γ- and AKT/PKB-signalling prevented PDGF-BB-induced contraction, whereas inhibition of EP4 only slightly reduced it. Accordingly, PDGF-BB increased TXA2 in the perfusate, whereas PGI2 was increased in all groups after 120 min and inhibition of IP-receptors did not enhance PDGF-BB-induced contraction. Moreover, PDGF-BB increased cAMP in PVs and inhibition of adenyl cyclase enhanced PDGF-BB-induced contraction, whereas inhibition of NO-formation only slightly increased it. Conclusions PDGF-BB/PDGFR regulates the pulmonary vascular tone by the generation of prostaglandins, the increase of calcium, the activation of MAPK- or PI3K/AKT/mTOR signalling and actin remodelling. More insights in PDGF-BB downstream-signalling may contribute to develop new therapeutics for PH.
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Affiliation(s)
- Annette D Rieg
- Department of Anaesthesiology, Medical Faculty RWTH-Aachen, Aachen, Germany.
| | - Said Suleiman
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Carolin Anker
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Eva Verjans
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Rolf Rossaint
- Department of Anaesthesiology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
| | - Christian Martin
- Institute of Pharmacology and Toxicology, Medical Faculty RWTH-Aachen, Aachen, Germany
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Cui B, Li K, Gai Z, She X, Zhang N, Xu C, Chen X, An G, Ma Q, Wang R. Chronic Noise Exposure Acts Cumulatively to Exacerbate Alzheimer's Disease-Like Amyloid-β Pathology and Neuroinflammation in the Rat Hippocampus. Sci Rep 2015; 5:12943. [PMID: 26251361 PMCID: PMC4528219 DOI: 10.1038/srep12943] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 07/10/2015] [Indexed: 11/27/2022] Open
Abstract
A putative etiological association exists between noise exposure and Alzheimer’s disease (AD). Amyloid-β (Aβ) pathology is thought to be one of the primary initiating factors in AD. It has been further suggested that subsequent dysregulation of Aβ may play a mechanistic role in the AD-like pathophysiology associated with noise exposure. Here, we used ELISA, immunoblotting, cytokine arrays, and RT-PCR, to examine both hippocampal Aβ pathology and neuroinflammation in rats at different time points after noise exposure. We found that chronic noise exposure significantly accelerated the progressive overproduction of Aβ, which persisted for 7 to 14 days after the cessation of exposure. This effect was accompanied by up-regulated expression of amyloid precursor protein (APP) and its cleavage enzymes, β- and γ-secretases. Cytokine analysis revealed that chronic noise exposure increased levels of tumor necrosis factor-α and the receptor for advanced glycation end products, while decreasing the expression of activin A and platelet-derived growth factor- AA. Furthermore, we found persistent elevations of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 expression that closely corresponded to the noise-induced increases in Aβ and neuroinflammation. These studies suggest that lifelong environmental noise exposure may have cumulative effects on the onset and development of AD.
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Affiliation(s)
- Bo Cui
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Kang Li
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Zhihui Gai
- 1] Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China [2] Shandong academy of occupational health and occupational medicine, Shandong academy of medical sciences, Jinan, China
| | - Xiaojun She
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Na Zhang
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Chuanxiang Xu
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Xuewei Chen
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Gaihong An
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Qiang Ma
- Department of Occupational Hygiene, Tianjin Institute of Health and Environmental Medicine, Tianjin, China
| | - Rui Wang
- Shandong academy of occupational health and occupational medicine, Shandong academy of medical sciences, Jinan, China
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Krogh KA, Lyddon E, Thayer SA. HIV-1 Tat activates a RhoA signaling pathway to reduce NMDA-evoked calcium responses in hippocampal neurons via an actin-dependent mechanism. J Neurochem 2014; 132:354-66. [PMID: 25156524 DOI: 10.1111/jnc.12936] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 08/06/2014] [Accepted: 08/20/2014] [Indexed: 01/27/2023]
Abstract
HIV-associated neurocognitive disorders afflict approximately half of HIV-infected patients. HIV-infected cells within the CNS release neurotoxic viral proteins such as the transactivator of transcription (Tat). Tat caused a biphasic change in NMDAR function; NMDA-evoked increases in intracellular Ca(2+) were initially potentiated following 16 h exposure to Tat and then adapted by gradually returning to baseline by 24 h. Following Tat-induced NMDAR potentiation, a RhoA/Rho-associated protein kinase (ROCK) signaling pathway was activated; a subsequent remodeling of the actin cytoskeleton reduced NMDA-evoked increases in intracellular Ca(2+) . Pharmacologic or genetic inhibition of RhoA or ROCK failed to affect potentiation, but prevented adaptation of NMDAR function. Activation of RhoA/ROCK signaling increases the formation of filamentous actin. Drugs that prevent changes to filamentous actin blocked adaptation of NMDAR function following Tat-induced potentiation, whereas stimulating either depolymerization or polymerization of actin attenuated NMDAR function. These findings indicate that Tat activates a RhoA/ROCK signaling pathway resulting in actin remodeling and subsequent reduction of NMDAR function. Adaptation of NMDAR function may be a mechanism to protect neurons from excessive Ca(2+) influx and could reveal targets for the treatment of HIV-associated neurocognitive disorders.
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Affiliation(s)
- Kelly A Krogh
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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M. Vargas L, Leal N, Estrada LD, González A, Serrano F, Araya K, Gysling K, Inestrosa NC, Pasquale EB, Alvarez AR. EphA4 activation of c-Abl mediates synaptic loss and LTP blockade caused by amyloid-β oligomers. PLoS One 2014; 9:e92309. [PMID: 24658113 PMCID: PMC3962387 DOI: 10.1371/journal.pone.0092309] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/21/2014] [Indexed: 01/04/2023] Open
Abstract
The early stages of Alzheimer's disease are characterised by impaired synaptic plasticity and synapse loss. Here, we show that amyloid-β oligomers (AβOs) activate the c-Abl kinase in dendritic spines of cultured hippocampal neurons and that c-Abl kinase activity is required for AβOs-induced synaptic loss. We also show that the EphA4 receptor tyrosine kinase is upstream of c-Abl activation by AβOs. EphA4 tyrosine phosphorylation (activation) is increased in cultured neurons and synaptoneurosomes exposed to AβOs, and in Alzheimer-transgenic mice brain. We do not detect c-Abl activation in EphA4-knockout neurons exposed to AβOs. More interestingly, we demonstrate EphA4/c-Abl activation is a key-signalling event that mediates the synaptic damage induced by AβOs. According to this results, the EphA4 antagonistic peptide KYL and c-Abl inhibitor STI prevented i) dendritic spine reduction, ii) the blocking of LTP induction and iii) neuronal apoptosis caused by AβOs. Moreover, EphA4-/- neurons or sh-EphA4-transfected neurons showed reduced synaptotoxicity by AβOs. Our results are consistent with EphA4 being a novel receptor that mediates synaptic damage induced by AβOs. EphA4/c-Abl signalling could be a relevant pathway involved in the early cognitive decline observed in Alzheimer's disease patients.
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Affiliation(s)
- Lina M. Vargas
- Departamento de Biología Celular y Molecular, Laboratorio de Señalización Celular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Nancy Leal
- Departamento de Biología Celular y Molecular, Laboratorio de Señalización Celular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Lisbell D. Estrada
- Departamento de Biología Celular y Molecular, Laboratorio de Señalización Celular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Adrian González
- Departamento de Biología Celular y Molecular, Laboratorio de Señalización Celular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Felipe Serrano
- Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Katherine Araya
- Departamento de Biología Celular y Molecular, Millenium Nucleus in Stress and Addiction, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Katia Gysling
- Departamento de Biología Celular y Molecular, Millenium Nucleus in Stress and Addiction, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Nibaldo C. Inestrosa
- Departamento de Biología Celular y Molecular, Centro de Envejecimiento y Regeneración (CARE), Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Elena B. Pasquale
- Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Alejandra R. Alvarez
- Departamento de Biología Celular y Molecular, Laboratorio de Señalización Celular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
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Ma XM, Miller MB, Vishwanatha KS, Gross MJ, Wang Y, Abbott T, Lam TT, Mains RE, Eipper BA. Nonenzymatic domains of Kalirin7 contribute to spine morphogenesis through interactions with phosphoinositides and Abl. Mol Biol Cell 2014; 25:1458-71. [PMID: 24600045 PMCID: PMC4004595 DOI: 10.1091/mbc.e13-04-0215] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Like several Rho GDP/GTP exchange factors (GEFs), Kalirin7 (Kal7) contains an N-terminal Sec14 domain and multiple spectrin repeats. A natural splice variant of Kalrn lacking the Sec14 domain and four spectrin repeats is unable to increase spine formation; our goal was to understand the function of the Sec14 and spectrin repeat domains. Kal7 lacking its Sec14 domain still increased spine formation, but the spines were short. Strikingly, Kal7 truncation mutants containing only the Sec14 domain and several spectrin repeats increased spine formation. The Sec14 domain bound phosphoinositides, a minor but crucial component of cellular membranes, and binding was increased by a phosphomimetic mutation. Expression of KalSec14-GFP in nonneuronal cells impaired receptor-mediated endocytosis, linking Kal7 to membrane trafficking. Consistent with genetic studies placing Abl, a non-receptor tyrosine kinase, and the Drosophila orthologue of Kalrn into the same signaling pathway, Abl1 phosphorylated two sites in the fourth spectrin repeat of Kalirin, increasing its sensitivity to calpain-mediated degradation. Treating cortical neurons of the wild-type mouse, but not the Kal7(KO) mouse, with an Abl inhibitor caused an increase in linear spine density. Phosphorylation of multiple sites in the N-terminal Sec14/spectrin region of Kal7 may allow coordination of the many signaling pathways contributing to spine morphogenesis.
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Affiliation(s)
- Xin-Ming Ma
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030 WM Keck Foundation Biotechnology Resource Laboratory, Yale/NIDA Neuroproteomics Center, Yale University, New Haven, CT 06511
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Zhao YJ, Wang H, Liu X, Sun M, Kazuhiro H. Protective effects of glutamine in a rat model of endotoxemia. Mol Med Rep 2012; 6:739-44. [PMID: 22842774 DOI: 10.3892/mmr.2012.1007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 07/20/2012] [Indexed: 11/05/2022] Open
Abstract
The aim of this study was to characterize the protective effects of glutamine (Gln) on brain cells undergoing experimental endotoxemia induced by lipopolysaccharide (LPS) injection. Young rats were injected with LPS or control, and a subset of LPS-injected rats were pretreated with Gln. Electron microscopy and immunohistochemistry were used to visualize apoptosis and to determine distribution and expression of nuclear factor-κB (NF-κB), heat shock protein 70 (HSP70), platelet-derived growth factor-B (PDGF-B) and PDGF receptor-β (PDGFR-β). The levels of HSP70, PDGF-B and PDGFR-β in the rat brain were comparatively analyzed by western blotting. In a rat brain model of endotoxemia, Gln decreases the magnitude of apoptosis, upregulates the expression of HSP70 and inhibits the translocation of NF-κB from the cytoplasm to the nucleus. Gln upregulates PDGF-B and PDGFR-β expression in early and advanced sepsis. PDGF-B and PDGFR-β upregulation in the cerebral cortex are likely neuroprotective effects of Gln. We found that Gln is capable of regulating the immunological defense of local brain tissue, which provides a theoretical basis for using Gln to prevent and treat encephalopathy.
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Affiliation(s)
- Ya-Juan Zhao
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, Liaoning, PR China.
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Jayakar SS, Margiotta JF. Abelson family tyrosine kinases regulate the function of nicotinic acetylcholine receptors and nicotinic synapses on autonomic neurons. Mol Pharmacol 2011; 80:97-109. [PMID: 21502378 DOI: 10.1124/mol.111.071308] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Abelson family kinases (AFKs; Abl1, Abl2) are non-receptor tyrosine kinases (NRTKs) implicated in cancer, but they also have important physiological roles that include regulating synaptic structure and function. Recent studies using Abl-deficient mice and the antileukemia drug STI571 [imatinib mesylate (Gleevec); Novartis], which potently and selectively blocks Abl kinase activity, implicate AFKs in regulating presynaptic neurotransmitter release in hippocampus and postsynaptic clustering of nicotinic acetylcholine receptors (nAChRs) in muscle. Here, we tested whether AFKs are relevant for regulating nAChRs and nAChR-mediated synapses on autonomic neurons. AFK immunoreactivity was detected in ciliary ganglion (CG) lysates and neurons, and STI571 application blocked endogenous Abl tyrosine kinase activity. With similar potency, STI571 specifically reduced whole-cell current responses generated by both nicotinic receptor subtypes present on CG neurons (α3*- and α7-nAChRs) and lowered the frequency and amplitude of α3*-nAChR-mediated excitatory postsynaptic currents. Quantal analysis indicated that the synaptic perturbations were postsynaptic in origin, and confocal imaging experiments revealed they were unaccompanied by changes in nAChR clustering or alignment with presynaptic terminals. The results indicate that in autonomic neurons, Abl kinase activity normally supports postsynaptic nAChR function to sustain nAChR-mediated neurotransmission. Such consequences contrast with the influence of Abl kinase activity on presynaptic function and synaptic structure in hippocampus and muscle, respectively, demonstrating a cell-specific mechanism of action. Finally, because STI571 potently inhibits Abl kinase activity, the autonomic dysfunction side effects associated with its use as a chemotherapeutic agent may result from perturbed α3*- and/or α7-nAChR function.
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Affiliation(s)
- Selwyn S Jayakar
- Department of Neurosciences, University of Toledo College of Medicine, Toledo, Ohio 43614-5804, USA
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