Motivation: Wound-related diseases affect 2% of the world population, causing millions of cases of disability and >$150 billion in annual global healthcare costs. During the re-epithelialization phase of wound healing, keratinocytes in the basal layer of the epidermis migrate collectively as a single sheet across the wound bed to heal the wound. The planar cell polarity (PCP) signaling pathway is vital to this process, providing directional cues that drive keratinocyte migration toward the wound. Although PCP signaling has been widely studied in flies (Drosophila), much remains unknown about how PCP cluster assembly controls collective cell migration during wound healing. Our vision is to build on fundamental discoveries made in fruit flies and translate them into human skin models to improve the lives of people with wound-related diseases.
Aim: Establish reconstructed human epidermis (RHE) as a model for studying planar cell polarity (PCP) signaling in human skin
Rationale: We found that tissue polarity requires PCP clusters to grow sufficiently large, but whether this occurs in human skin remains unknown. RHE models offer a human-relevant, ethical, reproducible, and versatile alternative to animal testing, suitable for regulatory safety testing and mechanistic skin research. We aim to establish RHE as a model for studying the role of PCP signaling in wound healing, and we hypothesize that cluster size regulates PCP signaling in human skin.
Strategy: We will use a fully mature, stratified RHE model system developed with TERT-immortalized keratinocytes and fibroblasts, in collabocation with the Perez-Moreno Lab (Dept of Biology, Uni of Copenhagen). We will 1) use confocal microscopy to visualize PCP clusters in the basal epidermal layer, immunostained for PCP isoforms strongly expressed in skin (Vangl2 and Fz6); 2) investigate whether these clusters polarize as expected using super-resolution methods (2-color SIM/STED); 3) determine whether the asymmetry within individual clusters increases with size, as expected based on prior studies; and 4) characterize spatiotemporal changes in PCP cluster size using confocal microscopy after introducing a reproducible wound (biopsy punch) or other stressors (irritation/UV exposure).Outcome: We expect 1) to find PCP clusters apically in the epidermal basal layer of 3D human skin cultures, as reported for mouse epidermis; 2) that these PCP clusters polarize, as expected; and 3) that the asymmetry of individual clusters, as measured by the imbalance of Vangl2 and Fz6, will increase with cluster size. Based on extant knowledge, We hypothesize that clusters will repolarize to match the direction of collective cell migration; and 4) that clusters may shrink or remodel in response to tissue repair. These experiments, regardless of their specific outcomes, will provide the first causal study directly linking PCP signaling to wound healing in a human model.
Contact: If you find this interesting, please reach out to silas_boye.nissen@med.lu.se
Best Silas