Neuroscience Letters 565 (2014) 1
Contents lists available at ScienceDirect
Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet
Introduction
Astrocytes are ubiquitous throughout the central nervous system (CNS), and in the uninjured CNS perform a myriad of functions, including maintenance of extracellular ionic homeostasis, uptake and release of neurotransmitters, and participation in regulation of blood flow and the blood–brain barrier [1,2]. In response to a variety of insults to the CNS, astrocytes become “reactive”, a graded process that involves alterations in gene expression, cellular hypertrophy, proliferation and often formation of a glial scar, and has been termed “astrogliosis” [3,4,7]. For decades, the astrocytic response to injury was primarily viewed in terms of morphological/structural changes in these cells. This assessment has changed radically during the past twenty years, with accumulating data indicative of reactive astrocytes playing a much more complex role in the response to and recovery from CNS injury [5,6]. As reviewed in this Special Issue, advances in our understanding of astrocyte biology following insult include new observations about their structure, organization, and function. Indeed, recent work has convincingly demonstrated reactive astrocytes can subserve protective roles for neuronal survival after brain injury. Nevertheless, other work has pointed to an inhibitory role of the glial scar formed by astrocytes and other cellular constituents. It is becoming appreciated that reactive astrogliosis is a complex phenomenon that includes a mixture of positive and negative responses for neuronal survival and regeneration. Reactive astroglia maintain the integrity of the blood–brain barrier and the survival of the peri-lesion tissue, but may prevent axonal and damaged tissue regeneration. In this Special Issue, the astrocytic mechanisms that have evolved to protect the brain against the consequences of injury are contrasted with the key roles of astrocytes in neuronal survival and regeneration failure. In this context, the chapters presented in
0304-3940/$ – see front matter © 2014 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.neulet.2014.01.052
the Special Issue highlight particularly the double-edged role of reactive astrocytes, providing an awareness of destructive versus protective mechanisms of the astrocytic response and a framework for astrocytes as therapeutic targets following brain injury. References [1] B. Ransom, T. Behar, M. Nedergaard, New roles for astrocytes (stars at last), Trends Neurosci. 26 (2003) 520–522. [2] N.A. Oberheim, X. Wang, S. Goldman, M. Nedergaard, Astrocytic complexity distinguishes the human brain, Trends Neurosci. 29 (2006) 547–553. [3] M. Pekny, M. Nilsson, Astrocyte activation and reactive gliosis, Glia (2005) 427–434. [4] J.L. Zamanian, L. Xu, L.C. Foo, N. Nouri, L. Zhou, R.G. Giffard, B.A. Barres, Genomic analysis of reactive astrogliosis, J. Neurosci. 32 (2012) 6391–6410. [5] B.A. Barres, The mystery and magic of glia: a perspective on their roles in health and disease, Neuron 60 (2008) 430–440. [6] H. Franke, A. Verkhratsky, G. Burnstock, P. Illes, Pathophysiology of astroglial purinergic signalling, Purinergic Signal. 8 (2012) 629–657. [7] M.V. Sofroniew, Molecular dissection of reactive astrogliosis and glial scar formation, Trends Neurosci. 32 (2009) 638–647.
George E. Barreto (M.Sc. Ph.D.) ∗ Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá DC, Colombia Joel A. Black (Ph.D.) Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA ∗ Corresponding author. E-mail address: [email protected] (G.E. Barreto)
Contents lists available at ScienceDirect
Neuroscience Letters journal homepage: www.elsevier.com/locate/neulet
Introduction
Astrocytes are ubiquitous throughout the central nervous system (CNS), and in the uninjured CNS perform a myriad of functions, including maintenance of extracellular ionic homeostasis, uptake and release of neurotransmitters, and participation in regulation of blood flow and the blood–brain barrier [1,2]. In response to a variety of insults to the CNS, astrocytes become “reactive”, a graded process that involves alterations in gene expression, cellular hypertrophy, proliferation and often formation of a glial scar, and has been termed “astrogliosis” [3,4,7]. For decades, the astrocytic response to injury was primarily viewed in terms of morphological/structural changes in these cells. This assessment has changed radically during the past twenty years, with accumulating data indicative of reactive astrocytes playing a much more complex role in the response to and recovery from CNS injury [5,6]. As reviewed in this Special Issue, advances in our understanding of astrocyte biology following insult include new observations about their structure, organization, and function. Indeed, recent work has convincingly demonstrated reactive astrocytes can subserve protective roles for neuronal survival after brain injury. Nevertheless, other work has pointed to an inhibitory role of the glial scar formed by astrocytes and other cellular constituents. It is becoming appreciated that reactive astrogliosis is a complex phenomenon that includes a mixture of positive and negative responses for neuronal survival and regeneration. Reactive astroglia maintain the integrity of the blood–brain barrier and the survival of the peri-lesion tissue, but may prevent axonal and damaged tissue regeneration. In this Special Issue, the astrocytic mechanisms that have evolved to protect the brain against the consequences of injury are contrasted with the key roles of astrocytes in neuronal survival and regeneration failure. In this context, the chapters presented in
0304-3940/$ – see front matter © 2014 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.neulet.2014.01.052
the Special Issue highlight particularly the double-edged role of reactive astrocytes, providing an awareness of destructive versus protective mechanisms of the astrocytic response and a framework for astrocytes as therapeutic targets following brain injury. References [1] B. Ransom, T. Behar, M. Nedergaard, New roles for astrocytes (stars at last), Trends Neurosci. 26 (2003) 520–522. [2] N.A. Oberheim, X. Wang, S. Goldman, M. Nedergaard, Astrocytic complexity distinguishes the human brain, Trends Neurosci. 29 (2006) 547–553. [3] M. Pekny, M. Nilsson, Astrocyte activation and reactive gliosis, Glia (2005) 427–434. [4] J.L. Zamanian, L. Xu, L.C. Foo, N. Nouri, L. Zhou, R.G. Giffard, B.A. Barres, Genomic analysis of reactive astrogliosis, J. Neurosci. 32 (2012) 6391–6410. [5] B.A. Barres, The mystery and magic of glia: a perspective on their roles in health and disease, Neuron 60 (2008) 430–440. [6] H. Franke, A. Verkhratsky, G. Burnstock, P. Illes, Pathophysiology of astroglial purinergic signalling, Purinergic Signal. 8 (2012) 629–657. [7] M.V. Sofroniew, Molecular dissection of reactive astrogliosis and glial scar formation, Trends Neurosci. 32 (2009) 638–647.
George E. Barreto (M.Sc. Ph.D.) ∗ Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá DC, Colombia Joel A. Black (Ph.D.) Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA ∗ Corresponding author. E-mail address: [email protected] (G.E. Barreto)
