Identification and non-invasive measurement of biomarkers of radiation exposure in human skin

Brigham And Women'S Hospital, Boston MA

Investigators

Abstract

Project Summary Abstract: The skin is a barrier tissue that is impacted by all types of external radiation events and is accessible to non- invasive testing. Tape stripping of the skin is an effective, well established, and non-invasive method for sampling both protein and RNA biomarkers in human skin. We have developed a model of studying radiation injury in human skin by irradiating living human skin grafts carried by immunodeficient NSG mice. Our model recapitulates both the early inflammatory and late fibrotic changes in skin observed in patients after radiation exposure. We present pilot spatial profiling and immunostaining data demonstrating that superficial keratinocytes, the cell population sampled by non-invasive tape stripping, upregulate RNA and protein biomarkers within 24 hours of radiation exposure and that different biomarkers have the potential to discriminate between 1, 2 and 5 Gy radiation. In this proposal, we will identify optimal keratinocyte biomarkers of radiation exposure and develop a point-of-care test to measure them using non-invasive tape stripping. In Aim 1, we will identify, validate and measure the expression kinetics of keratinocyte biomarkers of radiation exposure (0, 1, 2, 5 Gy) in human skin grafts carried by NSG mice. Xenium 5000 plex spatial transcriptional profiling will be used to identify candidate biomarkers (Aim 1A), followed by single cell proteomic measurement of candidate biomarkers using cyclic immunofluorescence (CyCIF) in both discovery and validation sample cohorts (Aim 1B,C). The kinetics of protein biomarker expression will then be evaluated via CyCIF on days 1, 2, 3, 5, and 7 after 1, 2, or 5 Gy irradiation (Aim 1D). In Aim 2, we will use NSG mice grafted with neonatal foreskin and skin obtained from aged patients (>65 years) to study the utility of identified biomarkers in pediatric and aged individuals. In Aim 3, we will develop and test a point-of-care test to measure biomarkers using non-invasive tape stripping of the skin. These studies will generate validated, human cutaneous biomarkers of radiation exposure and a non-invasive test to measure them that is immediately applicable to the care of humans exposed to radiation.