Signaling pathways of ATP‐induced PGE2 release in spinal cord astrocytes are EGFR transactivation‐dependent

M Xia, Y Zhu - Glia, 2011 - Wiley Online Library
M Xia, Y Zhu
Glia, 2011Wiley Online Library
Traumatic spinal cord injury is characterized by an immediate, irreversible loss of tissue at
the lesion site, as well as a secondary expansion of tissue damage over time. Although
secondary injury should, in principle, be preventable, no effective treatment options currently
exist for patients with acute spinal cord injury (SCI). Excessive release of ATP by the
traumatized tissue, triggers the rapid release of arachidonic acid (AA) and prostaglandin E2
(PGE2), and has beenimplicated in acute and chronic neuropathic pain and inflammation …
Abstract
Traumatic spinal cord injury is characterized by an immediate, irreversible loss of tissue at the lesion site, as well as a secondary expansion of tissue damage over time. Although secondary injury should, in principle, be preventable, no effective treatment options currently exist for patients with acute spinal cord injury (SCI). Excessive release of ATP by the traumatized tissue, triggers the rapid release of arachidonic acid (AA) and prostaglandin E2 (PGE2), and has beenimplicated in acute and chronic neuropathic pain and inflammation. But the intracellular pathways between ATP and PGE2 remain largely unknown. We have explored the signaling events involved in this synthesis by primarily culturing spinal cord astrocytes: (1) we determined significant PGE2 production increased by ATP is mainly via Subtype 1 of P2 purinoceptors (P2Y1) but not P2Y2; (2) we found that ATP strongly increased the level of intracellular Ca2+ via P2Y1 receptor; (3) we indicated that ATP stimulates the definitely release of AA and PGE2 which involved the transactivation of epidermal growth factor (EGF) receptor, the phosphorylation of extracellular‐regulated protein kinases 1 and 2 (ERK1/2) and the activation of cytosolic phospholipase A2 (cPLA2); (4) we examined ATP could increase the phosphorylation of Akt via P2Y1 receptor which also depend on the transactivation of EGFR, but the activation of Akt has no effect on the downstream of cPLA2 phosphorylation. ATP induced by SCI could mobilize the release of AA and PGE2. And inhibition of PGE2 release reduces behavioral signs of pain after SCI and peripheral nerve injury. © 2011 Wiley‐Liss, Inc.
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