UC San Diego

Wound healing begins as soon as the wound occurs and can continue for days, weeks, or even months. Although decades of research have established the multiple-steps required to heal a wound, little is known about the cellular response immediately following the wound. Furthermore, because the location of the wound is relevant to the healing process, healthy cells responding to a wound require positional information, or knowing where they are in relation to the wound. Thus, there are two important questions not fully understood in wound healing: 1. How do cells know where they are? and 2. How do the initial signaling mechanisms influence downstream genetic expression and overall healing? Here, using recent technological advancements in single-cell fluorescent microscopy and fluorescent biomarkers, we determine that ATP, an initial signaling molecule released from wounded cells, creates spatial patterns immediately following an epithelial wound using a simple Release and Diffusion mechanism. Then we determine that epithelial cells use paracrine signaling to spatially average the initial wound response signals over a specific distance to maximize the signal-to-noise ratio. Finally, we establish a method titled SpaSeq (Spatial Sequencing) that utilizes FACS and RNA-Seq in addition to fluorescent proteins to measure the spatio-temporal gene expression patterns following a wound.