Reactive oxygen species (ROS) modulate AMPA receptor phosphorylation and cell-surface localization in concert with pain-related behavior

Abstract

Sensitization of dorsal horn neurons (DHNs) in the spinal cord is dependent on pain-related synaptic plasticity and causes persistent pain. The DHN sensitization is mediated by a signal transduction pathway initiated by the activation of NMDA receptors (NMDA-Rs). Recent studies have shown that elevated levels of reactive oxygen species (ROS) and phosphorylation-dependent trafficking of GluA2 subunit of AMPA receptors (AMPA-Rs) are a part of the signaling pathway for DHN sensitization. However, the relationship between ROS and AMPA-R phosphorylation and trafficking is not known. Thus, this study investigated the effects of ROS scavengers on the phosphorylation and cell-surface localization of GluA1 and GluA2. Intrathecal NMDA- and intradermal capsaicin-induced hyperalgesic mice were used for this study since both pain models share the NMDA-R activation-dependent DHN sensitization in the spinal cord. Our behavioral, biochemical, and immunohistochemical analyses demonstrated that: 1) NMDA-R activation in vivo increased the phosphorylation of AMPA-Rs at GluA1 (S818, S831, and S845) and GluA2 (S880) subunits, 2) NMDA-R activation in vivo increased cell-surface localization of GluA1 but decreased that of GluA2, and 3) reduction of ROS levels by ROS scavengers PBN or TEMPOL reversed these changes in AMPA-Rs, as well as pain-related behavior. Given that AMPA-R trafficking to the cell surface and synapse is regulated by NMDA-R activation-dependent phosphorylation of GluA1 and GluA2, our study suggests that the ROS-dependent changes in the phosphorylation and cell-surface localization of AMPA-Rs are necessary for DHN sensitization and thus pain-related behavior. We further suggest that ROS reduction will ameliorate these molecular changes and pain.

Inflammation-induced GluA1 trafficking and membrane insertion of Ca2+ permeable AMPA receptors in dorsal horn neurons is dependent on spinal tumor necrosis factor, PI3 kinase and protein kinase A

“…The mechanisms of insertion and deletion are beginning to be elucidated, e.g. GluA2 removal from the membrane is NMDA receptor dependent and requires phosphorylation of GluA2 at ser 880 (Beattie et al, 2000; D. Z. Lee et al, 2012; Malinow and Malenka, 2002; Park et al, 2009; Seidenman et al, 2003).…”

Oxidative Stress and the Central Nervous System

“…And, oxidative stress-initiated neuroendocrine alterations within the amygdala, including amygdalar hyperactivity and dendritic shrinking (Wellman, 2001;Vyas et al, 2002;Kreibich and Blendy 2004;Brown et al, 2005;Radley et al, 2006;Wood et al, 2010), can further potentiate synaptic disturbances by disrupting the hippocampus-amygdala projections. Furthermore, free radicals are known to oxidize the extracellular sites of glutamatergic N-methyl-D-aspartate receptors, leading to attenuation of LTP and synaptic neurotransmission (Haxaire et al, 2012;Lee et al, 2012;Rai et al, 2013). Collectively, these events offer an attractive explanation for oxidative stress-induced behavioral and cognitive impairment.…”

Gain with no pain? Pain management in dermatological photodynamic therapy

“…We have discussed that PpIX fluorescence positively correlates with pain experience during PDT. As the product of PpIX metabolism and effector of PDT, ROS initiate pain, especially neuropathic and capsaicin‐induced pain . ROS increase phosphorylation of N ‐methyl‐ d ‐aspartate and AMPA (α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid) receptors and decreases GABA release .…”

“…ROS can directly activate and sensitize nociceptive neurons, and can also evoke pain indirectly by mediating release of inflammatory factors. [19][20][21][22][57][58][59] There is evidence suggesting that GABA receptors are involved in nociception during PDT. 60,61 For example, Yowtak et al showed that GABA receptors can also be inhibited by ROS.…”

“…As the product of PpIX metabolism and effector of PDT, ROS initiate pain, especially neuropathic and capsaicin-induced pain. 21,22,57,58 ROS increase phosphorylation of N-methyl-D-aspartate and AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors and decreases GABA release. 21,22,58 As a result, nociceptive neurons are induced to fire or fire more frequently.…”