Purinoreceptor P2X7 Regulation of Ca2+ Mobilization and Cytoskeletal Rearrangement Is Required for Corneal Reepithelialization after Injury

Abstract

The process of wound healing involves a complex network of signaling pathways working to promote rapid cell migration and wound closure. Activation of purinergic receptors by secreted nucleotides plays a major role in calcium mobilization and the subsequent calcium-dependent signaling that is essential for proper healing. The role of the purinergic receptor P2X7 in wound healing is still relatively unknown. We demonstrate that P2X7 expression increases at the leading edge of corneal epithelium after injury in an organ culture model, and that this change occurs despite an overall decrease in P2X7 expression throughout the epithelium. Inhibition of P2X7 prevents this change in localization after injury and impairs wound healing. In cell culture, P2X7 inhibition attenuates the amplitude and duration of injuryinduced calcium mobilization in cells at the leading edge. Immunofluorescence analysis of scratchwounded cells reveals that P2X7 inhibition results in an overall decrease in the number of focal adhesions along with a concentration of focal adhesions at the wound margin. Live cell imaging of green fluorescent proteinelabeled actin and talin shows that P2X7 inhibition alters actin cytoskeletal rearrangements and focal adhesion dynamics after injury. Together, these data demonstrate that P2X7 plays a critical role in mediating calcium signaling and coordinating cytoskeletal rearrangement at the leading edge, both of which processes are early signaling events necessary for proper epithelial wound healing. (Am J Pathol 2016, 186: 285e296; http://dx

Antimicrobial endotoxin‐neutralizing peptides promote keratinocyte migration via P2X7 receptor activation and accelerate wound healing in vivo

“…We could previously show that purinergic receptors appear to be involved in Pep19‐2.5‐induced keratinocyte migration (Pfalzgraff et al ., ). Various AMPs can modulate or activate the P2X7 receptor (Elssner et al ., ; Ferrari et al ., ; Sommer et al ., ) which plays a critical role in epithelial cell migration (Minns et al ., ). To gain further insights into the role of purinergic receptors for Pep19‐2.5‐promoted cell migration, we therefore performed a wound scratch assay with P2X7 receptor antagonists in HaCaT keratinocytes.…”

CFTR Involvement in Cell Migration and Epithelial Restitution

“…The elevation in intracellular [Ca 2+ ] was shown to augment formation of myosin II containing stress fibers necessary for efficient cell migration. Similarly, ionotropic P2X 7 receptors have also been shown to contribute to changes in intracellular [Ca 2+ ] and cell migration. During injury of corneal epithelial cells, P2X 7 receptors redistribute to the leading edge of cells that border the wound [7].…”

“…Similarly, ionotropic P2X 7 receptors have also been shown to contribute to changes in intracellular [Ca 2+ ] and cell migration. During injury of corneal epithelial cells, P2X 7 receptors redistribute to the leading edge of cells that border the wound [7]. Adenosine triphosphate (ATP) is released from the damaged cells leading to activation of these receptors and subsequent uptake of Ca 2+ from the extracellular solution.…”

Phosphate‐dependent luminal ATP metabolism regulates transcellular calcium transport in intestinal epithelial cells

“…4 C ). As the P2X7 ATP receptor has been shown to mediate ATP‐dependent calcium flux (26), we investigated the involvement of this receptor by using a potent competitive P2X7 ATP receptor antagonist, A438079. Blockade of P2X7 decreased ATP‐γ‐S‐evoked calcium influx (Fig.…”