Alpha2-Adrenergic-Agonist Brimonidine Stimulates Negative Feedback and Attenuates Injury-Induced Phospho-ERK and Dedifferentiation of Chicken Müller Cells
2015 (English)In: Investigative Ophthalmology and Visual Science, ISSN 0146-0404, E-ISSN 1552-5783, Vol. 56, no 10, 5933-5945 p.Article in journal (Refereed) Published
Retinal injury induces Müller cell dedifferentiation by activating extracellular signal-regulated kinase (ERK) signaling. Stimulation of α2-adrenergic receptors protects against injury but also activates ERK in Müller cells. The purpose of this work was to study the effect of α2-adrenergic signaling on injury-induced ERK and Müller cell dedifferentiation. We tested the hypothesis that α2-stimulation triggers negative feedback regulation of the injury-induced ERK pathway that attenuates Müller cell dedifferentiation.
Chicken retina injured by N-methyl-D-aspartate and cultured primary Müller cells were stimulated by the α2-adrenergic agonist brimonidine. Immunostaining, quantitative RT-PCR, and Western blot techniques in combination with receptor blockers were used for analysis of the cellular responses.
Alpha2-adrenergic receptor stimulation attenuated injury-induced ERK activation and dedifferentiation of Müller cells as seen by decreased phospho-ERK, expression of transitin, and retinal progenitor cell genes. The attenuation was concomitant with a synergistic upregulation of several negative ERK-signal feedback regulators including ERK-phosphatases, Raf1-, and growth factor receptor–binding proteins. The results were also seen in cultures of primary Müller cells.
Alpha2-adrenergic signaling on Müller cells elicits an intracellular attenuation of the injury response that comprises negative ERK-signaling feedback leading to attenuated Müller cell dedifferentiation. The implications of this study are that adrenergic stress signals may directly modulate glial function in retina and that α2-adrenergic receptor pharmacology may be used to control glial injury response.
Place, publisher, year, edition, pages
2015. Vol. 56, no 10, 5933-5945 p.
IdentifiersURN: urn:nbn:se:uu:diva-262700DOI: 10.1167/iovs.15-16816ISI: 000368426300032OAI: oai:DiVA.org:uu-262700DiVA: diva2:854937
FunderSwedish Research Council, M 12187