Personalized expression of bitter ‘taste’ receptors in human skin

The integumentary (i.e., skin) and gustatory systems both function to protect the human body and are a first point of contact with poisons and pathogens. These systems may share a similar protective mechanism because both human taste and skin cells express mRNA for bitter taste receptors (TAS2Rs). Here, we used gene-specific methods to measure mRNA from all known bitter receptor genes in adult human skin from freshly biopsied samples and from samples collected at autopsy from the Genotype-Tissue Expression project. Human skin expressed some but not all TAS2Rs, and for those that were expressed, the relative amounts differed markedly among individuals. For some TAS2Rs, mRNA abundance was related to sun exposure (TAS2R14, TAS2R30, TAS2R42, and TAS2R60), sex (TAS2R3, TAS2R4, TAS2R8, TAS2R9, TAS2R14, and TAS2R60), and age (TAS2R5), although these effects were not large. These findings contribute to our understanding of extraoral expression of chemosensory receptors.