Basement membrane components are key players in specialized extracellular matrices

Abstract

More than three decades ago, basement membranes (BMs) were described as membrane-like structures capable of isolating a cell from and connecting a cell to its environment. Since this time, it has been revealed that BMs are specialized extracellular matrices (sECMs) with unique components that support important functions including differentiation, proliferation, migration, and chemotaxis of cells during development. The composition of these sECM is as unique as the tissues to which they are localized, opening the possibility that such matrices can fulfill distinct functions. Changes in BM composition play significant roles in facilitating the development of various diseases. Furthermore, tissues have to provide sECM for their stem cells during development and for their adult life. Here, we briefly review the latest research on these unique sECM and their components with a special emphasis on embryonic and adult stem cells and their niches.

Fig. 1

Laminin-111 is found in the very early mouse embryo, here shown at day 6, even before a proper BM has assembled (a) and in BM remnants of migrating mesodermal cells (b) at day 7. M Mesodermal cell, N nucleus, S mesodermal space, EC ectodermal cell. (Taken from [200], with permission from the publisher). In adult murine kidney, the tail (formerly the E8 domain) of laminin-111 is orientated towards the lamina fibroreticularis in the basement membrane of the proximal tubule (c), while the molecule is randomly distributed in the distal tubule (d). C Cell, BM basement membrane. (Taken from [44], with permission from the publisher)

Fig. 2

Perlecan is found in the pericellular matrix next to a healthy chondrocyte (a) and increased amounts next to an elongated chondrocyte (b) from osteoarthritic tissue. (Taken from [23], with permission from the publisher)

Fig. 3

The interconnected networks of laminin-111 (large gold particles) and collagen IV (small gold particles) is here shown in a basement membrane of the kidney. The inset shows a higher magnification. BM Basement membrane. (Taken from [201], with permission from the publisher)

Fig. 4

More nidogen-2 is found in the BM of skeletal muscle in nidogen-1 knockout mice compared to control mice (a), sparse labeling of muscle BM of a control mouse (b), and a higher amount seen in a nidogen-1 knockout mouse (c). (Taken from [99], with permission from the publisher)

Fig. 5

Nidogen-2 (b) exhibits a more restricted tissue distribution in human articular cartilage than nidogen-1 (a). (Taken from [22], with permission from the publisher)

Fig. 6

Tissue from late stages of osteoarthritis exhibits brakes in the tidemark (a) through these mesenchymal cells and blood vessels enter the cartilage tissue (b), perhaps bring in stem cells from the mesenchyme underneath (c). The progenitor cells are positive for STRO-1 (d) and CD29 (e), two so-called stem cell marker. (Taken from [199], with permission from the publisher)