Transmembrane collagens—Unexplored mediators of epidermal‐dermal communication and tissue homeostasis

Abstract

Tissue homeostasis is maintained through constant, dynamic and heterogeneous communication between cells and their microenvironment. Proteins that are at the same time active at the intracellular, cell periphery and deeper extracellular levels possess the ability to, on the individual molecular level, influence the cells and their microenvironment in a bidirectional manner. The transmembrane collagens are a family of such proteins, which are of notable interest for tissue development and homeostasis. In skin, expression of all transmembrane collagens has been reported and deficiency of transmembrane collagen XVII manifests with distinct skin phenotypes. Nevertheless, transmembrane collagens in skin remain understudied despite the association of them with epidermal wound healing and dermal fibrotic processes. Here, we present an overview of transmembrane collagens and put a spotlight on them as regulators of epidermal-dermal communication and as potential players in fibrinogenesis.

Main and Minor Types of Collagens in the Articular Cartilage: The Role of Collagens in Repair Tissue Evaluation in Chondral Defects

“…All members of this group are also shed from the cell surface, generating soluble forms. They are found in numerous cell types and stand out for its cell adhesive properties [10,40].…”

More than just bricks and mortar: Fibroblasts and ECM in skin health and disease

“…First is the basement membrane, which provides attachment for keratinocytes and is composed of a complex network of collagen IV, nidogen, laminins and their interacting partners (reviewed in this issue by Aumailley 2 ). Transmembrane collagens extend from basal keratinocytes into the underlying dermis, forming anchoring fibrils and associated structures and are involved in providing mechanical strength as well as enabling epidermal‐dermal communication (reviewed in this issue by Nystrom and Kiritsi 3 and Watanabe et al 4 ). A large number of inherited and acquired skin diseases occur due to mutations in one of the basement membrane proteins or due to circulating autoantibodies binding to these structures 5 …”

Epidermal changes during tail regeneration in the Bahamas lancelet, Asymmetron lucayanum (Cephalochordata)

“…Unlike vertebrates, cephalochordates have a monolayered epidermis before, during and after regeneration, so the results of such studies would be uncomplicated by any overlying epidermal cell layers. Finally, it may well be that the molecular basis of epidermal wound repair in vertebrates—for instance, the key roles of galectins (Argüeso et al, 2015) and transmembrane collagens (Nyström & Kiritsi, 2021)—will be found to have similar functions in cephalochordates and can serve as a guide for further research.…”