Spatiotemporal dynamics of PIEZO1 localization controls keratinocyte migration during wound healing

Abstract

Keratinocytes are the predominant cell type of the epidermis and form an important protective barrier to the external environment. During the healing of wounded skin, keratinocytes migrate from the wound edge to reinstate the epithelial barrier. Mechanical cues are important regulators of cell migration in this process; however, the molecular transducers and biophysical mechanisms of this mechanoregulation remain elusive. Here, we show through molecular, cellular and organismal studies that the mechanically-activated ion channel PIEZO1 regulates keratinocyte migration through dynamic cellular localization which dictates retraction events. Single keratinocytes isolated from an epidermal-specific _Piezo1_ knockout mouse moved faster and migrated farther than littermate controls. To determine how PIEZO1 may contribute to cell migration, we imaged the localization of endogenous channels in migrating keratinocytes over several hours. We found that enrichment of PIEZO1 channel puncta correlated with cellular retraction in migrating single cells and in collectively migrating monolayers. Strikingly, PIEZO1 activation with Yoda1 resulted in increased retraction events in single cells as well as in monolayers of keratinocytes. During in vitro scratch assays, Yoda1-induced activation of PIEZO1 caused slower wound closure due to increased retraction events at the wound. Conversely, channel deletion resulted in faster scratch wound closure. This result was mirrored in vivo whereby epidermal-specific PIEZO1 knockout mice exhibited faster wound closure compared to littermate controls, and epidermal-specific PIEZO1 gain-of-function mice displayed slower wound closure. Overall, our findings show that reducing Piezo1 activity can accelerate wound healing, suggesting a potential pharmacological target for wound treatment. More broadly, we show that molecular-scale spatiotemporal dynamics of Piezo1 channels controls tissue-scale cell migration, a cellular process of fundamental importance in development, homeostasis and repair.

Piezo1 and Piezo2 foster mechanical gating of K2P channels

“…Notably, genetic invalidation of Piezo1 or TREK/TRAAK in the mouse fibroblasts similarly causes an acceleration of gum wound healing following injury, showing that both MSCs act in concert. Interestingly, epidermal specific Piezo1 knockout mice also exhibits faster wound closure, while epidermal-specific Piezo1 gain-of-function mice displayed slower healing (Holt et al, 2021). Thus, Piezo1 appears to play a similar role both in skin and gum wound healing, delaying the healing process.…”

“…A major difference between skin and gum wound healing is the remarkable absence of hypertrophic gingival scar (Ha ¨kkinen et al, 2000). Thus, it is tempting to speculate that TREK-1/ 2 opening downstream of Piezo1 in gingival fibroblasts may act as a secondary brake along with Piezo1 (Holt et al, 2021), delaying wound healing and thereby possibly contributing to the remarkable scarless property of the gums. If the brake is less powerful in the skin (with a lower TREK/TRAAK expression), hypertrophic scar is more likely to form.…”

An inter-channel cooperative mechanism mediates PIEZO1’s exquisite mechanosensitivity

“…This hypothetical mode of channel regulation would constitute a remarkably effective mechanism to modulate cellular mechanosensitivity without altering the total number of channels at the cell surface, which would require slow and costly membrane trafficking processes. Such a potential regulatory mechanism seems plausible, as a recent study suggests cell migration is accompanied by a dynamic redistribution of endogenous PIEZO1 channels at the cell surface 45 . Future studies will be needed to determine if and how channel density in PIEZO1 clusters changes as a function of physiological and pathological contexts.…”

“An intrinsically disordered intracellular domain of PIEZO2 is required for force-from-filament activation of the channel”

“…PIEZO2, on the other hand, appears to be particularly important for mechanotransduction in primary sensory afferents as it was shown to be involved in the detection of light touch, mechanical pain, proprioception, airway stretch and bladder distension [4][5][6][7][8][9][10][11] . Moreover, PIEZOs contribute to the regulation of processes such as neurite outgrowth 12 , wound healing 13 and tumor cell dissemination 14 , probably by detecting cell-generated traction forces acting on the plasma membrane during neurite extension and cell migration [15][16][17] .…”