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Fil D, Borysiewicz E, Konat GW. A broad upregulation of cerebral chemokine genes by peripherally-generated inflammatory mediators. Metab Brain Dis 2011; 26:49-59. [PMID: 21258854 DOI: 10.1007/s11011-010-9231-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 12/21/2010] [Indexed: 12/22/2022]
Abstract
Previously, we have shown that peripheral challenge of mice with double stranded RNA (dsRNA), a viral mimic, evokes global upregulation of cerebral inflammatory genes and, particularly, genes encoding chemokines. Because chemokine networks are potent modulators of brain function, the present study was undertaken to comprehensively characterize the cerebral response of chemokine ligand and receptor genes to peripheral immune system stimulation. Briefly, C57BL/6 mice were intraperitoneally injected with 12 mg/kg of polyinosinic-polycytidylic acid (PIC) and the expression of 39 mouse chemokine ligand and 20 receptor genes was monitored in the cerebellum by real time quantitative RT-PCR within 24 h. Almost half of the ligand genes featured either transient or sustained upregulation from several- to several thousand-fold. Five CXC type genes, i.e., Cxcl9, Cxcl11, Cxcl10, Cxcl2 and Cxcl1, were the most robustly upregulated, and were followed by six CC type genes, i.e., Ccl2, Ccl7, Ccl5, Ccl12, Ccl4 and Ccl11. Seven genes showed moderate upregulation, whereas the remaining genes were unresponsive. Six receptor genes, i.e., Cxcr2, Ccr7, Cxcr5, Ccr6, Ccr1 and Ccr5, featured a several-fold upregulation. Similar chemokine gene response was observed in the forebrain and brainstem. This upregulation of chemokine genes could be induced in naïve mice by transfer of blood plasma from PIC-challenged mice. Employing oligodeoxynucleotide-labeled PIC we further showed that intraperitoneally injected PIC was not transferred to the blood. In conclusion, peripheral PIC challenge elicits a broad upregulation of cerebral chemokine genes, and this upregulation is mediated by blood-borne agents.
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Affiliation(s)
- Daniel Fil
- Department of Neurobiology and Anatomy, West Virginia University School of Medicine, 4052 HSN, P.O. Box 9128, Morgantown, WV 26506-9128, USA
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52
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Chronic exposure to the chemokine CCL3 enhances neuronal network activity in rat hippocampal cultures. J Neuroimmunol 2010; 229:73-80. [PMID: 20678811 DOI: 10.1016/j.jneuroim.2010.07.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 06/26/2010] [Accepted: 07/07/2010] [Indexed: 11/20/2022]
Abstract
We examined the effect of chronic CCL3 treatment on the properties of cultured rat hippocampal neurons to gain an understanding of the neuronal effects of CCL3 during neuroinflammatory disorders. Western blot assays showed that chronic exposure to CCL3 altered the level of specific neuronal and glial proteins and that CCL3 had no effect on neuronal survival. CCL3 treatment also altered intracellular Ca(2+) dynamics and increased Ca(2+) levels in hippocampal neurons, measured by fura-2 imaging techniques. Additionally, chronic CCL3 increased NMDA-evoked Ca(2+) signals in the hippocampal neurons and increased NMDA receptor levels. These CCL3-induced neuroadaptive changes could play an important role in the CNS dysfunction associated with CNS disorders with a neuroinflammatory component.
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53
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Zhang B, Patel J, Croyle M, Diamond MS, Klein RS. TNF-alpha-dependent regulation of CXCR3 expression modulates neuronal survival during West Nile virus encephalitis. J Neuroimmunol 2010; 224:28-38. [PMID: 20579746 DOI: 10.1016/j.jneuroim.2010.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 05/04/2010] [Indexed: 12/17/2022]
Abstract
The chemokine CXCL10 exerts antiviral effects within the central nervous system (CNS) through the recruitment of virus-specific T cells. However, elevated levels of CXCL10 may induce neuronal apoptosis given its receptor, CXCR3, is expressed by neurons. Using a murine model of West Nile virus (WNV) encephalitis, we determined that WNV-infected neurons express TNF-alpha, which down-regulates neuronal CXCR3 expression via signaling through TNFR1. Down-regulation of neuronal CXCR3 decreased CXCL10-mediated calcium transients and delayed Caspase 3 activation. Loss of CXCR3 activation, via CXCR3-deficiency or pretreatment with TNF-alpha prevented neuronal apoptosis during in vitro WNV infection. These results suggest that neuronal TNF-alpha expression during WNV encephalitis may be an adaptive response to diminish CXCL10-induced death.
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Affiliation(s)
- Bo Zhang
- Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA
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54
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Müller M, Carter S, Hofer MJ, Campbell IL. Review: The chemokine receptor CXCR3 and its ligands CXCL9, CXCL10 and CXCL11 in neuroimmunity - a tale of conflict and conundrum. Neuropathol Appl Neurobiol 2010; 36:368-87. [DOI: 10.1111/j.1365-2990.2010.01089.x] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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55
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Yuan Y, Liu J, Liu Z, He Y, Zhang Z, Jiang C, Qian Q. Chemokine CCL3 facilitates the migration of hepatoma cells by changing the concentration intracellular Ca. Hepatol Res 2010; 40:424-31. [PMID: 20236357 DOI: 10.1111/j.1872-034x.2009.00619.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIM Recurrence and metastasis are the major factors associated with the poor prognosis of hepatocellular carcinoma (HCC). It was confirmed that multiple chemokines and their receptors are related to the progression and metastasis of HCC. The aim of this research was to conduct an investigation into whether macrophage inflammatory protein-1alpha/CCL3, and its receptor CCR1 play a role in HCC invasion and metastasis. METHODS We used reverse transcription polymerase chain reaction, immunocytochemistry and flow cytometry to detect CCR1 mRNA and protein expression in the four hepatoma cell lines HepG2, Hep3B, HLE and HLF; and we conducted a microscope cell migration experiment to observe the pseudopodia formation and mobility of the hepatoma cells. The concentration of intracellular calcium was measured by fluorescence microscopy. RESULTS CCR1 mRNA and protein were positively expressed in the four hepatoma cell lines HepG2, Hep3B, HLE and HLF. Following CCL3 stimulation, obvious pseudopodia formation of hepatoma cells was observed using a fluorescence microscope. The cell migration experiment showed that after incubation with CCL3, the number of Hep3B cells which passed through the polycarbonate microporous filter membranes increased to an obvious extent. After CCL3 incubation, the intracellular Ca(2+) level of the Hep3B cells increased to an obvious extent. CONCLUSION Chemokine CCL3 facilitates the migration of hepatoma by changing the concentration intracellular Ca(2+). The CCL3-CCR1 axis may play an important role in HCC invasion and metastasis. It may also be a potential target for HCC therapy or for prevention of the recurrence and metastasis of HCC.
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Affiliation(s)
- Yufeng Yuan
- Division of Hepatobiliary Surgery, Department of Surgery, Zhongnan Hospital, Wuhan University, Wuhan, China
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56
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Cho J, Nelson TE, Bajova H, Gruol DL. Chronic CXCL10 alters neuronal properties in rat hippocampal culture. J Neuroimmunol 2009; 207:92-100. [PMID: 19167097 DOI: 10.1016/j.jneuroim.2008.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 11/24/2008] [Accepted: 12/12/2008] [Indexed: 10/21/2022]
Abstract
The chemokine CXCL10 is expressed in the central nervous system (CNS) during neuroinflammatory conditions. Neurons express CXCR3, the receptor for CXCL10, and neuronal function has been shown to be altered by acute exposure to CXCL10. Little is known about the effects of chronic exposure to CXCL10 on neuronal function. Results from our studies show that chronic exposure of cultured rat hippocampal neurons to CXCL10 results in altered levels of protein for GABA and glutamate receptors and altered synaptic network activity. These effects of CXCL10 may contribute to altered CNS function that occurs in some chronic neuroinflammatory conditions.
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Affiliation(s)
- Jungsook Cho
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, CA 92037, USA.
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57
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Sheng H, Sun T, Cong B, He P, Zhang Y, Yan J, Lu C, Ni X. Corticotropin-releasing hormone stimulates SGK-1 kinase expression in cultured hippocampal neurons via CRH-R1. Am J Physiol Endocrinol Metab 2008; 295:E938-46. [PMID: 18713960 DOI: 10.1152/ajpendo.90462.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Corticotropin-releasing hormone (CRH) has been shown to exhibit various functions in hippocampus. In the present study, we examined the effect of CRH on the expression of serum/glucocorticoid-inducible protein kinase-1 (SGK-1), a novel protein kinase, in primary cultured hippocampal neurons. A dose-dependent increase in mRNA and protein levels of SGK-1 as well as frequency of SGK-1-positive neurons occurred upon exposure to CRH (1 pmol/l to 10 nmol/l). These effects can be reversed by the specific CRH-R1 antagonist antalarmin but not by the CRH-R2 antagonist astressin 2B. Blocking adenylate cyclase (AC) activity with SQ22536 and PKA with H89 completely prevented CRH-induced mRNA and protein expression of SGK-1. Blockage of PLC or PKC did not block CRH-induced SGK-1 expression. Our results suggest that CRH act on CRH-R1 to stimulate SGK-1 mRNA and protein expression in cultured hippocampal neurons via a mechanism that is involved in AC/PKA signaling pathways.
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Affiliation(s)
- Hui Sheng
- Departments of Physiology, Second Military Medical University, Shanghai, China
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58
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Cho J, Gruol DL. The chemokine CCL2 activates p38 mitogen-activated protein kinase pathway in cultured rat hippocampal cells. J Neuroimmunol 2008; 199:94-103. [PMID: 18584881 DOI: 10.1016/j.jneuroim.2008.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 04/25/2008] [Accepted: 05/19/2008] [Indexed: 11/24/2022]
Abstract
Emerging evidence indicates that chemokines can regulate both the physiology and biochemistry of CNS neurons and glia. In the current study, Western blot analysis showed that in rat hippocampal neuronal/glial cultures the signal transduction pathway activated by CCL2, a chemokine expressed in the normal brain and at elevated levels during neuroinflammation, involves a G-protein coupled receptor, p38 MAPK as well as its immediate upstream kinase MKK3/6, and the downstream transcription factor CREB. ERK 1/2 and the transcription factors STAT1 and STAT3 do not play a prominent role. CCL2 also altered Ca(2+) influx and synaptic network activity in the hippocampal neurons. These results suggest an important role for p38 MAPK and CREB in hippocampal actions of CCL2.
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Affiliation(s)
- Jungsook Cho
- Molecular and Integrative Neuroscience Department, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, United States.
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59
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Bajova H, Nelson TE, Gruol DL. Chronic CXCL10 alters the level of activated ERK1/2 and transcriptional factors CREB and NF-kappaB in hippocampal neuronal cell culture. J Neuroimmunol 2008; 195:36-46. [PMID: 18329727 DOI: 10.1016/j.jneuroim.2008.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 12/21/2007] [Accepted: 01/08/2008] [Indexed: 11/17/2022]
Abstract
Signal transduction pathways may be important targets of chemokines during neuroinflammation. In the current study, Western blot analyses show that in rat hippocampal neuronal/glial cell cultures chronic CXCL10 increases the level of protein for ERK1/2 as well as for the transcriptional factors CREB and NF-kappaB. Bcl-2, an anti-apoptotic protein whose expression can be regulated by a pathway involving ERK1/2, CREB and NF-kappaB, was also increased in the CXCL10 treated cultures. These results implicate a role for ERK1/2, CREB and NF-kappaB in effects of CXCL10 on hippocampal cells and suggest that chronic CXCL10 may have a protective role during certain neuroinflammatory conditions.
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Affiliation(s)
- Hilda Bajova
- Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, CA 92037, USA
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60
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Sheng H, Zhang Y, Sun J, Gao L, Ma B, Lu J, Ni X. Corticotropin-releasing hormone (CRH) depresses n-methyl-D-aspartate receptor-mediated current in cultured rat hippocampal neurons via CRH receptor type 1. Endocrinology 2008; 149:1389-98. [PMID: 18079206 DOI: 10.1210/en.2007-1378] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CRH, the primary regulator of the neuroendocrine responses to stress, has been shown to modulate synaptic efficacy and the process of learning and memory in hippocampus. However, effects of CRH on N-methyl-d-aspartate (NMDA) receptor, the key receptor for synaptic plasticity, remain unclear. In primary cultured hippocampal neurons, using the technique of whole-cell patch-clamp recordings, we found that CRH (1 pmol/liter to 10 nmol/liter) inhibited NMDA-induced currents in a dose-dependent manner. This effect was reversed by the CRH receptor type 1 (CRHR1) antagonist antalarmin but not by the CRHR2 antagonist astressin-2B, suggesting that CRHR1 mediated the inhibitory effect of CRH. Investigations on the signaling pathways of CRH showed that CRH dose-dependently induced phosphorylated phospholipase C (PLC)-beta3 expression and increased intracellular cAMP content in these cells. Blocking PLC activity with U73122 prevented CRH-induced depression of NMDA current, whereas blocking protein kinase A (H89) and adenylate cyclase (SQ22536) failed to affect the CRH-induced depression of NMDA current. Application of inositol-1,4,5-triphosphate receptor (IP(3)R) antagonist, Ca(2+) chelators or protein kinase C (PKC) inhibitors also mainly blocked CRH-induced depression of NMDA currents, suggesting involvement of PLC/IP(3)R/Ca(2+)and PLC/PKC signaling pathways in CRH down-regulation of NMDA receptors. Our results suggest that CRH may exert neuromodulatory actions on hippocampus through regulating NMDA receptor function.
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Affiliation(s)
- Hui Sheng
- Department of Physiology, Ministry of Education, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, People's Republic of China
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61
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Vereyken EJF, Bajova H, Chow S, de Graan PNE, Gruol DL. Chronic interleukin-6 alters the level of synaptic proteins in hippocampus in culture and in vivo. Eur J Neurosci 2007; 25:3605-16. [PMID: 17610580 DOI: 10.1111/j.1460-9568.2007.05615.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is now considerable evidence that the level of expression of the proinflammatory cytokine, interleukin-6 (IL-6), is increased in the central nervous system (CNS) during neuroinflammatory conditions such as occurs in neurological disorders and in disease and injury. However, our understanding of the consequences of increased expression of IL-6 on the CNS is still limited, especially with respect to the developing nervous system, which is known to be particularly vulnerable to environmental factors. To address this issue, we investigated the properties of cultured hippocampal neurons exposed chronically to IL-6 during the main period of morphological and physiological development, which occurs during the first 2 weeks of culture. IL-6 was tested at 500 U/mL, considered to reflect a pathophysiologic concentration. The morphological features of neuronal development in the control and IL-6-treated cultures appeared similar. However, Western blot analysis showed a significant reduction in the level of Group-II metabotropic receptors (mGluR2/3) and L-type Ca(2+) channels in the IL-6-treated cultures. A similar reduction in mGluR2/3 and L-type Ca(2+) channel protein was observed in transgenic mice that over-express IL-6 in the CNS through astrocyte production starting early in development. Analysis of Ca(2+) signals produced by spontaneous synaptic network activity in the hippocampal cultures and effects of a mGluR2/3 agonist and antagonist showed that the reduced levels of mGluR2/3 impact on the functional properties of hippocampal synaptic network activity. These results have important implications relative to the mechanisms responsible for altered CNS function during conditions associated with increased levels of IL-6 in the CNS.
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Affiliation(s)
- Elly J F Vereyken
- Department Pharmacology & Anatomy, Rudolf Magnus Institute of Neuroscience, UMCU, Utrecht, The Netherlands
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62
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de Haas AH, van Weering HRJ, de Jong EK, Boddeke HWGM, Biber KPH. Neuronal chemokines: versatile messengers in central nervous system cell interaction. Mol Neurobiol 2007; 36:137-51. [PMID: 17952658 PMCID: PMC2039784 DOI: 10.1007/s12035-007-0036-8] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Accepted: 01/17/2007] [Indexed: 01/07/2023]
Abstract
Whereas chemokines are well known for their ability to induce cell migration, only recently it became evident that chemokines also control a variety of other cell functions and are versatile messengers in the interaction between a diversity of cell types. In the central nervous system (CNS), chemokines are generally found under both physiological and pathological conditions. Whereas many reports describe chemokine expression in astrocytes and microglia and their role in the migration of leukocytes into the CNS, only few studies describe chemokine expression in neurons. Nevertheless, the expression of neuronal chemokines and the corresponding chemokine receptors in CNS cells under physiological and pathological conditions indicates that neuronal chemokines contribute to CNS cell interaction. In this study, we review recent studies describing neuronal chemokine expression and discuss potential roles of neuronal chemokines in neuron-astrocyte, neuron-microglia, and neuron-neuron interaction.
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Affiliation(s)
- A H de Haas
- Department of Medical Physiology, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, Groningen, 9713 AV, The Netherlands
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63
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Sui Y, Stehno-Bittel L, Li S, Loganathan R, Dhillon NK, Pinson D, Nath A, Kolson D, Narayan O, Buch S. CXCL10-induced cell death in neurons: role of calcium dysregulation. Eur J Neurosci 2006; 23:957-64. [PMID: 16519660 DOI: 10.1111/j.1460-9568.2006.04631.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chemokines play a key role in the regulation of central nervous system disease. CXCL10 over-expression has been observed in several neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease and HIV-associated dementia. More recent studies by others and us have shown that CXCL10 elicits apoptosis in fetal neurons. The mechanism of CXCL10-mediated neurotoxicity, however, remains unclear. In this study, we provide evidence for the direct role of Ca(2+) dysregulation in CXCL10-mediated apoptosis. We demonstrate that treatment of fetal neuronal cultures with exogenous CXCL10 produced elevations in intracellular Ca(2+) and that this effect was modulated via the binding of CXCL10 to its cognate receptor, CXCR3. We further explored the association of intracellular Ca(2+) elevations with the caspases that are involved in CXC10-induced neuronal apoptosis. Our data showed that increased Ca(2+), which is available for uptake by the mitochondria, is associated with membrane permeabilization and cytochrome c release from this compartment. The released cytochrome c then activates the initiator active caspase-9. This initiator caspase sequentially activates the effector caspase-3, ultimately leading to apoptosis. This study identifies the temporal signaling cascade involved in CXCL10-mediated neuronal apoptosis and provides putative targets for pharmaceutical intervention of neurological disorders associated with CXCL10 up-regulation.
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Affiliation(s)
- Yongjun Sui
- Department of Pathology and Microbiology, Marion Merrell Dow Laboratory of Viral Pathogenesis, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Abstract
Chronic (neuropathic) pain is one of the most widespread and intractable of human complaints, as well as being one of the most difficult syndromes to treat successfully with drugs or surgery. The development of new therapeutic approaches to the treatment of painful neuropathies requires a better understanding of the mechanisms that underlie the development of these chronic pain syndromes. It is clear that inflammatory responses often accompany the development of neuropathic pain, and here we discuss the idea that chemokines might be key to integrating the development of pain and inflammation and could furnish new leads in the search for effective analgesic agents for the treatment of painful neuropathies.
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Affiliation(s)
- Fletcher A White
- Department of Cell Biology, Neurobiology and Anatomy, Stritch School of Medicine, Loyola University, Maywood, Illinois 60153, USA
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65
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Liu L, Callahan MK, Huang D, Ransohoff RM. Chemokine receptor CXCR3: an unexpected enigma. Curr Top Dev Biol 2005; 68:149-81. [PMID: 16124999 DOI: 10.1016/s0070-2153(05)68006-4] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
CXCR3, the receptor for CXCL9/MIG, CXCL10/IP-10, and CXCL11/I-TAC, is preferentially expressed on activated Th1 T cells and has been predicted to play an important role in their trafficking. However, this simplistic view of the function of CXCR3 and its ligands has not been borne out by studies of disease models, including experimental autoimmune encephalomyelitis (EAE), using varied methods of receptor blockade, as well as knockout or transgenic mice. This review focuses on the current understanding of the enigmatic role of CXCR3 and its ligands in CNS inflammatory/autoimmune disorders. The conflicting results among varied models of CNS inflammation suggest complex and multiple roles for CXCR3 and its ligands in the pathogenesis of CNS inflammatory/autoimmune diseases. Thus, further study is needed to determine how CXCL10 neutralizing agents or CXCR3 receptor antagonists might be applied to treating human disease.
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Affiliation(s)
- Liping Liu
- Department of Neurosciences, Lerner Research Institute, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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66
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Gosselin RD, Varela C, Banisadr G, Mechighel P, Rostene W, Kitabgi P, Melik-Parsadaniantz S. Constitutive expression of CCR2 chemokine receptor and inhibition by MCP-1/CCL2 of GABA-induced currents in spinal cord neurones. J Neurochem 2005; 95:1023-34. [PMID: 16150057 DOI: 10.1111/j.1471-4159.2005.03431.x] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In the CNS, immune-like competent cells (microglia and astrocytes) were first described as potential sites of chemokine synthesis, but more recent evidence has indicated that neurones might also express chemokines and their receptors. The aim of the present work was to investigate further, both in vivo and in vitro, CC Chemokine Family Receptor 2 (CCR2) expression and functionality in rat spinal cord neurones. First, we demonstrated by RT-PCR and western blot analysis that CCR2 mRNA and protein were present in spinal extracts. Furthermore, we showed by immunolabelling that CCR2 was exclusively expressed by neurones in spinal sections of healthy rat. Finally, to test the functionality of CCR2, we used primary cultures of rat spinal neurones. In this model, similar to what was observed in vivo, CCR2 mRNA and protein were expressed by neurones. Cultured neurones stimulated with Monocyte Chemoattractant Protein-1 (MCP-1)/CCL2, the best characterized CCR2 agonist, showed activation of the Akt pathway. Finally, patch-clamp recording of cultured spinal neurones was used to investigate whether MCP-1/CCL2 could modulate their electrophysiological properties. MCP-1 alone did not affect the electrical properties of spinal neurones, but potently and efficiently inhibited GABA(A)-mediated GABAergic responses in these neurones. These data constitute the first demonstration of a modulatory role of MCP-1 on GABAergic neurotransmission and contribute to our understanding of the roles of CCR2 and MCP-1/CCL2 in spinal cord physiology, in particular with respect to nociceptive transmission, as well as the implication of this chemokine in neuronal adaptation or dysfunction during neuropathy.
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MESH Headings
- Animals
- Autoradiography/methods
- Bicuculline/pharmacology
- Blotting, Northern/methods
- Blotting, Western/methods
- Cells, Cultured
- Chemokine CCL2/pharmacology
- Dose-Response Relationship, Drug
- Drug Interactions
- ELAV Proteins/metabolism
- Embryo, Mammalian
- Female
- GABA Antagonists/pharmacology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/physiology
- Glial Fibrillary Acidic Protein/metabolism
- Immunohistochemistry/methods
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Neurons/drug effects
- Neurons/physiology
- Oncogene Protein v-akt/metabolism
- Patch-Clamp Techniques/methods
- Phosphorylation
- Pregnancy
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, CCR2
- Receptors, Chemokine/genetics
- Receptors, Chemokine/metabolism
- Reverse Transcriptase Polymerase Chain Reaction/methods
- Spinal Cord/cytology
- gamma-Aminobutyric Acid/pharmacology
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