Transient astrocytic mGluR5 expression drives synaptic plasticity and subsequent chronic pain in mice

• Published in: The Journal of experimental medicine Vol. 219; no. 4
• Main Authors: Danjo, Yosuke, Shigetomi, Eiji, Hirayama, Yukiho J, Kobayashi, Kenji, Ishikawa, Tatsuya, Fukazawa, Yugo, Shibata, Keisuke, Takanashi, Kenta, Parajuli, Bijay, Shinozaki, Youichi, Kim, Sun Kwang, Nabekura, Junichi, Koizumi, Schuichi
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 04.04.2022
• Subjects: Animals; Astrocytes - metabolism; Chronic Pain - pathology; Mice; Neuronal Plasticity; Neurons - metabolism; Receptor, Metabotropic Glutamate 5 - metabolism
• ISSN: 0022-1007; 1540-9538
• DOI: 10.1084/jem.20210989

Activation of astrocytes has a profound effect on brain plasticity and is critical for the pathophysiology of several neurological disorders including neuropathic pain. Here, we show that metabotropic glutamate receptor 5 (mGluR5), which reemerges in astrocytes in a restricted time frame, is essential for these functions. Although mGluR5 is absent in healthy adult astrocytes, it transiently reemerges in astrocytes of the somatosensory cortex (S1). During a limited spatiotemporal time frame, astrocytic mGluR5 drives Ca2+ signals; upregulates multiple synaptogenic molecules such as Thrombospondin-1, Glypican-4, and Hevin; causes excess excitatory synaptogenesis; and produces persistent alteration of S1 neuronal activity, leading to mechanical allodynia. All of these events were abolished by the astrocyte-specific deletion of mGluR5. Astrocytes dynamically control synaptic plasticity by turning on and off a single molecule, mGluR5, which defines subsequent persistent brain functions, especially under pathological conditions.