Mapping the molecular and structural specialization of the skin basement membrane for inter-tissue interactions

Abstract

21Inter-tissue interaction is fundamental to multicellularity. Although the basement 22 membrane (BM) is located at tissue interfaces, its mode of action in inter-tissue 23 interactions remains poorly understood, mainly because the molecular and structural 24 details of the BM at distinct inter-tissue interfaces remain unclear. By combining 25 quantitative transcriptomics and immunohistochemistry, we systematically identify the 26 cellular origin, molecular identity and tissue distribution of extracellular matrix molecules 27 in mouse hair follicles, and reveal that BM composition and architecture are exquisitely 28 specialized for distinct inter-tissue interactions, including epidermal-fibroblast, 29 epidermal-muscle and epidermal-nerve interactions. The epidermal-fibroblast interface, 30 namely, hair germ-dermal papilla interface, makes asymmetrically organized side-31 specific heterogeneity in BM, defined by the newly characterized interface, hook and 32 mesh BMs. One component of these BMs, laminin a5, is required for the topological and 33 functional integrity of hair germ-dermal papilla interactions. Our study highlights the 34 significance of BM heterogeneity in distinct inter-tissue interactions. tissues, where it serves to compartmentalize and also tightly integrate tissues 1, 2 . The 40 BM has several crucial roles: i) it provides structural support to cells that is essential for 41 the development of organ structures; ii) it signals to cells through adhesion receptors 42 such as integrins; iii) it controls the tissue distributions and activities of soluble growth 43 factors; and iv) its mechanical characteristics influence cell behavior 3, 4, 5 . Thus, the 44 composition and structure of the BM play critical roles in cell proliferation, 45 differentiation, migration, survival, polarity and positioning, underpinning many 46 fundamental biological phenomena, including the developmental patterning, inter-tissue 47 interactions and stem cell niche formation. 48The BM is composed of a large variety of molecules that exhibit 49 spatiotemporal expression patterns during development and homeostasis, indicating that 50 individual cell types are exposed to tailor-made BM niches 6, 7, 8 . In mammals, the entire 51 set of ECM molecules, called the matrixome or matrisome, is encoded by 52 approximately 300 ECM genes and there are also approximately 800 ECM-associated 53 genes, such as those encoding ECM-modifying enzymes and growth factors 7, 9 54 (http://matrisomeproject.mit.edu/). Although information about the unique distribution, 55 biochemical activities and in vivo functions of individual BM molecules has been 56 accumulated, the entire molecular landscape of the BM composition, including its 57 cellular origins, tissue localizations and pattern-forming processes, in all organs remains 58 largely unknown. One major reason for the difficulty in obtaining a comprehensive 59 Tsutsui et al. 4 understanding of the ECM's composition lies in the biochemical properties of ECM 60 proteins, including their la...

Natural product Shi-Bi-Man regulates lactic acid metabolism and drives hair follicle stem cell activation to promote hair regeneration

“…Laminins are large groups of extracellular α, β, and γ chain trimers in the basement membrane (BM) of skin. During hair follicle development, the composition of laminins in the basement membrane zone (BMZ) changes [30] . LN-332 is abundant beneath the interfollicular epidermis, whereas LN-511 is most abundant at the lower part of the hair follicle.…”

Vasculature-driven stem cell population coordinates tissue scaling in dynamic organs

“…Subcutaneous fat was removed from the skin with a scalpel, and the whole skin was incubated for 30 min in 0.25% trypsin to separate into the epidermis and dermis. The dermal tissue was cut into small pieces and treated with 0.2% collagenase type I (Gibco) at 37°C for 2 hours (50). Epidermal and dermal cells were dissociated into single cells by pipetting and passing through 40-m (Falcon) and 20-m [pluriSelect (PLS)] strainers.…”

3D mapping reveals a complex and transient interstitial matrix during murine renal development

“…Proteins were annotated based on the matrisome category and cellular compartment classifications (Table S1). 29,32 Functional characterization of matrisome proteins as "basement membrane", "interstitial matrix", and "other" was based on 5,13,33 with additional re-annotations based on review of histology in the literature for proteins observed in this study (Table S1). Proteins were indicated as part of the elastin-microfibril axis based on literature studies ( Figure S1).…”