Role of gap junctions between keratinocyte and melanocyte in melanogenesis

Abstract

The process of melanogenesis in melanocytes and the transport of melanin in the form of melanosomes to the neighboring keratinocytes are the key steps in human skin pigmentation. Keratinocytes and melanocytes interact in intricate manner to maintain the homeostasis. The present study was designed to understand the role of cell-cell interaction through the gap junctions between melanocytes and keratinocytes on melanogenesis. We show that, inhibition of the gap junctional activity between human keratinocytes and melanocytes in a coculture system using gap junction blocker lowers the expression of key regulatory genes of melanogenesis such as tyrosinase and microphthalmia-associated transcription factor (MITF). This was followed by concurrent decrease in tyrosinase protein levels and activity. Our results show the preliminary evidence for the regulation of melanogenesis in melanocytes through direct gap junctional communication by keratinocytes. Deciphering the mechanism and factors involved in the process would uncover the significance of gap junctions in melanogenesis.

Key words： melanocyte; keratinocyte; melanogenesis; gap junctions; cell communication

Acknowledgements

We thank the Department of Biotechnology, Ministry of Science and Technology, Government of India, for the financial support for this work. We are indebted to Dr. Vijay Kumar, Pediatric surgeon, Kasturba Medical College, Manipal University, Manipal, for providing the skin samples.

Divya Padma, K.Satyamoorthy and Kumar M.R. Bhat declare that they have no conflict of interest.

‚€This project has obtained the institutional ethical clearance before conducting the experiments. In this project, foreskin samples were obtained from children who were undergoing circumcision surgery for various purposes. Informed consent from the parents/guardian of the subjects were taken before collecting the samples.

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