Effect of metabotropic glutamate receptor 6 on cell morphology and melanosome transfer in melanocytes

The melanosome transfer pathway from melanocytes to keratinocytes has been extensively investigated; however, the underlying molecular mechanisms remain unclear. Therefore, the function of metabotropic glutamate receptor 6 (mGluR6) in the control of melanocyte-to-keratinocyte melanosome transfer, intracellular calcium levels in melanocytes, and the formation of filopodia were explored in this study. Primary melanocytes and keratinocytes were isolated from human foreskin samples. mGluR6 expression was suppressed using lentiviral-mediated short hairpin RNA (shRNA). Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), flow cytometry, and western blot analyses were used to assess filopodia formation, cytoskeletal organization, and melanosome transfer. We found that melanocytes expressed mGluR6 and that mGluR6 knockdown influenced the establishment of dendritic formation, melanocyte filopodia, and microphthalmia-associated transcription factors. Similarly, the efficiency of melanosome transfer from melanocytes to keratinocytes was reduced. According to these findings, melanosome transfer between melanocytes and keratinocytes mostly occurs by filopodia delivery, and mGluR6 directly influences melanosome transfer by altering melanocyte morphology. Comprehensive knowledge of melanosome transfer is essential when developing therapies for skin illnesses characterized by hyperpigmentation or hypopigmentation.