title: L-type voltage-operated calcium channels contribute to astrocyte activation In vitro.
abstract: We have found a significant upregulation of L-type voltage-operated Ca(++) channels (VOCCs) in reactive astrocytes. To test if VOCCs are centrally involved in triggering astrocyte reactivity, we used in vitro models of astrocyte activation in combination with pharmacological inhibitors, siRNAs and the Cre/lox system to reduce the activity of L-type VOCCs in primary cortical astrocytes. The endotoxin lipopolysaccharide (LPS) as well as high extracellular K(+) , glutamate, and ATP promote astrogliosis in vitro. L-type VOCC inhibitors drastically reduce the number of reactive cells, astrocyte hypertrophy, and cell proliferation after these treatments. Astrocytes transfected with siRNAs for the Cav1.2 subunit that conducts L-type Ca(++) currents as well as Cav1.2 knockout astrocytes showed reduce Ca(++) influx by ∼80% after plasma membrane depolarization. Importantly, Cav1.2 knock-down/out prevents astrocyte activation and proliferation induced by LPS. Similar results were found using the scratch wound assay. After injuring the astrocyte monolayer, cells extend processes toward the cell-free scratch region and subsequently migrate and populate the scratch. We found a significant increase in the activity of L-type VOCCs in reactive astrocytes located in the growing line in comparison to quiescent astrocytes situated away from the scratch. Moreover, the migration of astrocytes from the scratching line as well as the number of proliferating astrocytes was reduced in Cav1.2 knock-down/out cultures. In summary, our results suggest that Cav1.2 L-type VOCCs play a fundamental role in the induction and/or proliferation of reactive astrocytes, and indicate that the inhibition of these Ca(++) channels may be an effective way to prevent astrocyte activation. GLIA 2016. GLIA 2016;64:1396-1415.
authors.affiliation: Department of Pharmacology and Toxicology, Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo. NYS Center of Excellence, 701 Ellicott St., Buffalo, New York.
authors.forename: Veronica T
authors.initials: VT
authors.lastname: Cheli
authors.affiliation: Department of Pharmacology and Toxicology, Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo. NYS Center of Excellence, 701 Ellicott St., Buffalo, New York.
authors.forename: Diara A
authors.initials: DA
authors.lastname: Santiago González
authors.affiliation: Department of Pharmacology and Toxicology, Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo. NYS Center of Excellence, 701 Ellicott St., Buffalo, New York.
authors.forename: Jessica
authors.initials: J
authors.lastname: Smith
authors.affiliation: Department of Pharmacology and Toxicology, Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo. NYS Center of Excellence, 701 Ellicott St., Buffalo, New York.
authors.forename: Vilma
authors.initials: V
authors.lastname: Spreuer
authors.affiliation: Department of Physiology, Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan.
authors.forename: Geoffrey G
authors.initials: GG
authors.lastname: Murphy
authors.affiliation: Department of Pharmacology and Toxicology, Hunter James Kelly Research Institute, School of Medicine and Biomedical Sciences, SUNY, University at Buffalo. NYS Center of Excellence, 701 Ellicott St., Buffalo, New York.
authors.forename: Pablo M
authors.initials: PM
authors.lastname: Paez
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D005911:Gliosis / Q000378:metabolism / Q000473:pathology; D018698:Glutamic Acid / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008810:Mice, Inbred C57BL; D011188:Potassium / Q000378:metabolism
chemical_list: D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D002412:Cations; D016207:Cytokines; D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D011188:Potassium; D002118:Calcium
keywords: astrocyte; astrogliosis; calcium influx; voltage-operated Ca++ channels