Abstract
In skin, although the extracellular matrix (ECM) is highly developed in dermis and hypodermis, discrete intercellular spaces between cells of the living epidermal layers are also filled with ECM components. Herein, we review knowledge about structure, localization and role of epidermal hyaluronan (HA), a key ECM molecule. HA is a non-sulfated glycosaminoglycan non-covalently bound to proteins or lipids. Components of the basal lamina maintain some segregation between the epidermis and the underlying dermis, and all epidermal HA is locally synthesized and degraded. Functions of HA in keratinocyte proliferation and differentiation are still controversial. However, through interactions with partners, such as the TSG-6 protein, HA is involved in the formation, organization and stabilization of the epidermal ECM. In addition, epidermal HA is involved in the formation of an efficient epidermal barrier made of cornified keratinocytes. In atopic dermatitis (AD) with profuse alterations of the epidermal barrier, HA is produced in larger amounts by keratinocytes than in normal skin. Epidermal HA inside AD lesional skin is located in enlarged intercellular spaces, likely as the result of disease-related modifications of HA metabolism.
Highlights
Hyaluronan, called hyaluronic acid (HA), is a linear non-sulfated glycosaminoglycan (GAG) present in extracellular matrices (ECM) of vertebrates [1]
The present review focuses on HA in the epidermal extracellular matrix and its potential implication in atopic dermatitis, a disease associated with an altered epidermal barrier
HA is a glycosaminoglycan found in intercellular spaces
Summary
Hyaluronan, called hyaluronic acid (HA), is a linear non-sulfated glycosaminoglycan (GAG) present in extracellular matrices (ECM) of vertebrates [1]. First identified in the vitreous humor, HA is present in skin, muscles, skeleton, and synovial fluid where it plays a role in shock absorption. HA is involved in the establishment of a competent barrier and plays controversial roles in keratinocyte proliferation and differentiation. Some of these functions are made possible by its binding to the membrane receptor CD44 (see Section 3.5 below for further details on CD44) [6]. Other protein partners are involved in HA functions and ECM organization. The present review focuses on HA in the epidermal extracellular matrix and its potential implication in atopic dermatitis, a disease associated with an altered epidermal barrier
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
