Exosomes in skin photoaging: biological functions and therapeutic opportunity

Abstract

Exosomes are tiny extracellular vesicles secreted by most cell types, which are filled with proteins, lipids, and nucleic acids (non-coding RNAs, mRNA, DNA), can be released by donor cells to subsequently modulate the function of recipient cells. Skin photoaging is the premature aging of the skin structures over time due to repeated exposure to ultraviolet (UV) which is evidenced by dyspigmentation, telangiectasias, roughness, rhytides, elastosis, and precancerous changes. Exosomes are associated with aging-related processes including, oxidative stress, inflammation, and senescence. Anti-aging features of exosomes have been implicated in various in vitro and pre-clinical studies. Stem cell-derived exosomes can restore skin physiological function and regenerate or rejuvenate damaged skin tissue through various mechanisms such as decreased expression of matrix metalloproteinase (MMP), increased collagen and elastin production, and modulation of intracellular signaling pathways as well as, intercellular communication. All these evidences are promising for the therapeutic potential of exosomes in skin photoaging. This review aims to investigate the molecular mechanisms and the effects of exosomes in photoaging.

Keywords: Exosome; Skin photoaging; Stem cell; UV-induced signaling.

Fig. 1

Exosome are small membrane vesicles that are formed by internalization of plasma membrane and formation of early endosomes. The early endosomes transform to late endosomes through maturation, then late endosomes, which termed as multivesicular bodies (MVBs), undergo inward membrane budding intraluminal vesicles (ILVs). MVBs fusion with the plasma membrane leads to release ILVs, or exosomes, into the extracellular space. Exosomes contain various biomolecules depends on the cell type of origin. Lipids, proteins and nucleic acids are the common molecular constituents of the majority of exosomes [67]. Exosomes are also rich in cytokines, growth factor and antioxidant

Fig. 2

Exosomes derived from different types of stem cells can play an important role in reducing photoaging by entering the target cells and transferring their contents. UV radiation induce generation of reactive oxygen species (ROS), leading to DNA damage, activation of inflammatory pathway, production of matrix metalloproteinases (MMPs) and degradation of collagen fibers. Skin photoaging is characterized by structural change, appearance of wrinkles and pigmentation (Reviewed in [7]). Exosomes derived from stem cells can be served as novel treatment option for skin repair and regeneration. Administering exosomes in the form of lyophilized injection may be one of the effective approaches to repair photo-damaged skin