Ultraviolet B irradiation enhances the secretion of exosomes by human primary melanocytes and changes their exosomal miRNA profile

Zeren Shen,Jinjin Shao,Jinghong Xu,Jiaqi Sun,Pierre Busson

doi:10.1371/journal.pone.0237023

Abstract

ObjectiveMelanocytes play a central role in skin homeostasis. In this study, we focus on the function of melanocyte releasing exosomes as well as exosomal microRNAs (miRNAs) and investigate whether ultraviolet B (UVB) irradiation exerts an impact on it.Materials and methodsExosomes derived from human primary melanocytes were isolated through differential centrifugation and were identified in three ways, including transmission electron microscopy observation, nanoparticle tracking analysis, and Western blot analysis. Melanocytes were irradiated with UVB for the indicated time, and then melanin production and exosome secretion were measured. The exosomal miRNA expression profile of melanocytes were obtained by miRNA sequencing and confirmed by real-time PCR.ResultsExosomes derived from human primary melanocytes were verified. UVB irradiation induced melanin production and increased the exosome release by the melanocytes. In total, 15 miRNAs showed higher levels in UVB-irradiated melanocyte-derived exosomes compared with non-irradiated ones, and the top three upregulated exosomal miRNAs were miR-4488, miR-320d, and miR-7704 (fold change > 4.0).ConclusionIt is verified for the first time that UVB irradiation enhanced the secretion of exosomes by melanocytes and changed their exosomal miRNA profile. This findings open a new direction for investigating the communication between melanocytes and other skin cells, and the connection between UVB and skin malignant initiation.

Highlights

In the epidermis, which is the outermost thin layer of the skin, melanocytes move about to inject melanin into keratinocytes; they are in contact with Langerhans cells, with fibroblasts, with sensory neurons through their cutaneous axon terminals, and with endothelial cells [1,2,3]
It is verified for the first time that ultraviolet B (UVB) irradiation enhanced the secretion of exosomes by melanocytes and changed their exosomal miRNA profile
This findings open a new direction for investigating the communication between melanocytes and other skin cells, and the connection between UVB and skin malignant initiation

Summary

Introduction

In the epidermis, which is the outermost thin layer of the skin, melanocytes move about to inject melanin into keratinocytes; they are in contact with Langerhans cells, with fibroblasts, with sensory neurons through their cutaneous axon terminals, and with endothelial cells [1,2,3]. Cells communicate either via secreted soluble factors or via extracellular vesicles (EVs) [4,5]. Studies have shown that melanocytes are the target of exosomes secreted by other cells, such as keratinocytes [9,10,11]; as for exosomes derived from melanocytes, their role in other cells is rarely investigated. In addition to facilitating pigmentation, melanocytes possess an important defense mechanism to provide protection against ultraviolet (UV)-induced oxidative and genotoxic stresses, wherein they amplify and send signals to other cells within an organized regulatory network to maintain skin homeostasis [12]. We focus on the function of melanocyte releasing exosomes as well as exosomal microRNAs (miRNAs), and investigate whether UVB irradiation exerts an impact on it and on intercellular communication and skin malignant initiation

Methods

Results

Conclusion