METHODS: OR expression was examined by low input whole transcriptome sequencing of skin tape strips and biopsies collected from AD patients and healthy controls (NC). OR10G7 mRNA expression was analyzed by RT-PCR in AD and NC biopsies and primary human keratinocytes. OR10G7 expression in AD and NC skin samples was evaluated by fluorescent immunostaining.
RESULTS: 381 OR gene transcripts were found in the skin samples, with the greatest OR expression detected in the skin tape strips, corresponding to the upper granular layer of the skin. The gene ontology groups of “OR activity” and “chemical stimulus involved in sensory perception” were found to be down-regulated in AD as compared to NC skin. However, individual OR transcripts were significantly induced or inhibited in AD skin colonized by S. aureus. As shown by RT-PCR, OR10G7 mRNA expression was significantly (p<0.05) increased in AD as compared to NC whole biopsies. OR10G7 mRNA expression was detected in primary human keratinocytes. OR10G7 protein expression was found in the skin granular layer and was significantly upregulated in nonlesional AD as compared to NC skin (MFI, Mean+SE, 292±45 vs. 161±37, p<0.05).
CONCLUSIONS: This study demonstrates previously unrecognized OR expression in the skin and their modulation in AD, suggesting potential contribution of these receptors in sensing bacterial colonization and wound healing responses.