We previously identified a strong overexpression of GPRC5A (G Protein-Coupled Receptor Class C Group 5 Member A) in keratinocytes from the skin wound edges in vivo, and in response to stiffness modulations in vitro, concomitantly to the translocation of its C-terminal region into the nucleolus. To better understand the role of this receptor in keratinocyte mechano-sensing, GPRC5A knock-down was performed in N/TERT-1 cells using a short-hairpin RNA approach, and a recombinant polypeptide mimicking the C-terminal region of GPRC5A (GPRC5A-Rec) was tested to rescue cell phenotype. The behaviour of GPRC5AKD cell, treated or not, was addressed using viability or proliferation tests, as well as migration (scratch test, ibidi inserts) and adhesion (Percoll test, impedance measurement) assays, while cell stratification was evaluated in reconstructed epidermis. Meanwhile, to understand GPRC5A molecular mechanism, the cleavage sites and the molecular partners were studied by mass spectrometry. We first validated GPRC5A-Rec and our results showed a low toxicity, although a negative effect on proliferation was observed. GPRC5A-Rec was also shown to be translocated into the nucleus after 12 hours post-treatment. In vitro experiments demonstrated that GPRC5AKD promotes cells adhesion and delays the migration of keratinocytes, while GPRC5A-Rec showed a compensatory effect on cell adhesion and migration, leading to faster wound closure during scratch assay. Mass spectrometry analyses identified cleavage sites by endogenous proteases, and some potential cytoplasmic partners. Finally, GPRC5AKD cells induced large defects in epidermal differentiation and stratification. Ongoing experiments are conducted to determine whether GPRC5A-Rec could improve this defective phenotype. In conclusion, our results demonstrate a new molecular signalling in keratinocytes implicating the C-terminal region of GPRC5A. Moreover, the use of GPRC5A-Rec allows partial rescue and would offer an interesting tool to improve the re-epithelialization step.

ESDR604 - The nuclear translocation of GPRC5A receptor is responsible for the regulation of keratinocyte adhesion and migration.

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.