Purine receptor mediated actin cytoskeleton remodeling of human fibroblasts

Abstract

Earlier studies have shown that activation of adenosine A1 receptors on peripheral pain fibers contributes to acupuncture-induced suppression of painful input. In addition to adenosine, acupuncture triggers the release of other purines, including ATP and ADP that may bind to purine receptors on nearby fibroblasts. We here show that purine agonists trigger increase in cytosolic Ca 2+ signaling in a cultured human fibroblasts cell line. The profile of agonist-induced Ca2+ increases indicates that the cells express functional P2yR2 and P2yR4 receptors, as well as P2yR1 and P2xR7 receptors. Unexpectedly, purine-induced Ca2+ signaling was associated with a remodeling of the actin cytoskeleton. ATP induced a transient loss in F-actin stress fiber. The changes of actin cytoskeleton occurred slowly and peaked at 10 min after agonist exposure. Inhibition of ATP-induced increases in Ca2+ by cyclopiazonic acid blocked receptor-mediated cytoskeleton remodeling. The Ca2+ ionophore failed to induce cytoskeletal remodeling despite triggering robust increases in cytosolic Ca2+. These observations indicate that purine signaling induces transient changes in fibroblast cytoarchitecture that could be related to the beneficial effects of acupuncture.

Peripheral and Spinal Mechanisms of Pain and Dry Needling Mediated Analgesia: A Clinical Resource Guide for Health Care Professionals

“…Scar tissue and fibrotic tissue are typically painful, structurally thicker and less elastic than healthy tissue [112]. However, DN mediated mechanotransduction of fibroblasts may be able to help remodel painful tissue by dampening tissue tension via actin polymerization [110]. A number of studies have demonstrated the use of DN to reduce pain associated with scar [58,113] and fibrotic tissue [114] further supporting this possibility.…”

“…Simply put, a reduction of fibroblast stress fibers changes the viscoelastic properties of the cells, allowing them to be more easily remodeled. Interestingly, this process requires mechanotransduction, as using cyclopiazonic acid to increase intracellular Ca 2+ was not enough to alter the actin cytoskeleton in the absence of P2X/P2Y receptor activation [110]. Moreover, the inhibition of rho kinase, a product of DN-mediated mechanotransduction, prevented viscoelastic changes in fibroblasts [110,111].…”

“…Before doing so, however, the ATP is recognized by purinergic P2X/P2Y receptors on fibroblasts, resulting in an influx of cytosolic Ca 2+ [110]. The CWP leads to the transient disassembly of polymerized actin and the subsequent decrease in fibroblast stress fibers [110]. Simply put, a reduction of fibroblast stress fibers changes the viscoelastic properties of the cells, allowing them to be more easily remodeled.…”

“…The extracellular ATP is quickly broken down into adenosine, mediating the reduction in pain and inflammation typically associated with DN. Before doing so, however, the ATP is recognized by purinergic P2X/P2Y receptors on fibroblasts, resulting in an influx of cytosolic Ca 2+ [110]. The CWP leads to the transient disassembly of polymerized actin and the subsequent decrease in fibroblast stress fibers [110].…”

To be or not to Be: The Needling Sensation (de qi) in acupuncture

“…19 A role of purines (ATP, ADP, adenosine) in the periphery is supported by Goldman and collaborators who have shown that activation of adenosine A1 receptors on peripheral pain fibres contributes to acupunctureinduced suppression of painful input. [20][21][22] An obvious question is whether needling of skin or muscles makes a difference to the perception of de qi. Skin pain is a sharp, spatially localised sensation, whereas muscle pain is a dull and poorly localised one.…”