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Updated: Mar 13, 2026
Isolation of Primary Mouse Retinal Glial Müller Cells
Published on: August 30, 2024
Role of Purines in Müller Glia
Andreas Reichenbach1, Andreas Bringmann2
11 Paul Flechsig Institute of Brain Research, University of Leipzig , Leipzig, Germany .
Abstract:
Müller glia, the principal macroglia of the retina, express diverse subtypes of adenosine and metabotropic purinergic (P2Y) receptors. Müller cells of several species, including man, also express ionotropic P2X7 receptors. ATP is liberated from Müller cells after activation of metabotropic glutamate receptors and during osmotic and mechanical induction of membrane stretch; adenosine is released through equilibrative nucleoside transporters. Müller cell-derived purines modulate the neuronal activity and have autocrine effects, for example, induction of glial calcium waves and regulation of the cellular volume. Glial calcium waves induced by neuron-derived ATP mediate functional hyperemia in the retina. Purinergic signaling contributes to the induction of Müller cell gliosis, for example, of cellular proliferation and downregulation of potassium channels, which are important for the homeostatic functions of Müller cells. Purinergic glial calcium waves may also promote the long-range propagation of gliosis and neuronal degeneration across the retinal tissue. The osmotic ATP release is inhibited under pathological conditions. Inhibition of the ATP release may result in osmotic Müller cell swelling and dysregulation of the water transport through the cells; both may contribute to the development of retinal edema. Suppression of the osmotic ATP release and upregulation of the ecto-apyrase (NTPDase1), which facilitate the extracellular degradation of ATP and the formation of adenosine, may protect neurons and photoreceptors from death due to overactivation of P2X receptors. Pharmacological inhibition of P2X7 receptors and stimulation of adenosine receptors may represent clinical approaches to prevent retinal cell death and dysregulated cell proliferation, and to treat retinal edema.
Insights
Müller cells in the retina release purines that influence neuronal activity and glial responses. Dysregulation of this purinergic signaling can lead to retinal edema and cell death, suggesting therapeutic targets.
Area of Science:
- Neuroscience
- Ophthalmology
- Cell Biology
Background:
- Müller glia, the primary retinal macroglia, express various adenosine and purinergic receptors (P2Y, P2X7).
- These cells release adenosine and adenosine triphosphate (ATP) under physiological and pathological conditions.
- Purinergic signaling plays a crucial role in retinal function, homeostasis, and disease.
Purpose of the Study:
- To elucidate the role of purinergic signaling in Müller cell function and retinal pathophysiology.
- To explore the impact of purinergic signaling on glial calcium waves, gliosis, and retinal edema.
- To identify potential therapeutic strategies targeting purinergic receptors for retinal diseases.
Main Methods:
- Analysis of Müller glia receptor expression (adenosine, P2Y, P2X7).
- Investigation of ATP and adenosine release mechanisms from Müller cells.
- Examination of the effects of purinergic signaling on glial calcium dynamics and cellular volume.
- Assessment of purinergic signaling's contribution to Müller cell gliosis and neuronal survival.
Main Results:
- Müller cell-derived purines modulate neuronal activity and induce glial calcium waves.
- Purinergic signaling contributes to Müller cell gliosis, proliferation, and potassium channel downregulation.
- Inhibition of osmotic ATP release under pathological conditions can lead to Müller cell swelling and retinal edema.
- Suppression of ATP release and enhanced ATP degradation may protect retinal cells from excitotoxicity.
Conclusions:
- Purinergic signaling is a critical regulator of retinal homeostasis and a contributor to pathological processes like gliosis and edema.
- Targeting P2X7 receptors and stimulating adenosine receptors may offer therapeutic benefits for retinal diseases.
- Modulating purinergic signaling pathways presents a promising avenue for preventing retinal cell death and treating edema.
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