Engineered natural extracellular matrix platform for modelling skin diseases and identifying therapeutic targets

Dysregulation of the dermal extracellular matrix (ECM) drives skin pathologies by influencing tissue mechanics, dermal-epidermal adhesion, and disease progression. However, current in vitro models often fail to replicate native ECM complexity or disease-specific alterations, limiting mechanistic studies and therapeutic target discovery. This gap is particularly critical for untreatable skin fragility disorders, where abnormal dermal ECM underlies severe clinical manifestations.

This study aimed to develop and validate an engineered natural ECM (NatECM) platform that recapitulates key compositional and biomechanical features of fibroblast-derived dermal ECM. As a proof-of-concept, we applied NatECM to model clinically distinct variants of dystrophic epidermolysis bullosa (DEB), the skin fragility disorders prototype, to identify ECM-related and disease-specific alterations and to interrogate candidate therapeutic targets.

Primary fibroblasts from healthy donors and DEB patients were cultured to self-assemble their ECM, generating NatECM dermal equivalents. ECM organization was evaluated by immunostaining and ultrastructural analyses, nano- and macro-scale mechanical properties were measured by atomic force microscopy and uniaxial tensile testing, and ECM composition was characterized by proteomics. Functional relevance was evaluated by keratinocyte adhesion assays and fibulin-5 supplementation experiments.

NatECM reproduced intrinsic fibroblast-derived dermal ECM features and captured disease-associated mechanical and structural impairments characteristic of DEB. Across DEB variants, NatECM unveiled subtype-specific proteomic alterations that affect ECM structure and elastic fiber formation. We identified a "fragility quartet" - fibulin-5, decorin, and collagens III and V - consistently downregulated across all variants and linked to defective ECM mechanics. Fibulin-5 supplementation restored ECM elastic behavior and strengthened keratinocyte adhesion, supporting its role as a candidate ECM regulator.

The NatECM platform faithfully models fibroblast-derived dermal ECM and enables the identification and functional investigation of key molecular ECM regulators in DEB. Its tunability and physiological relevance position NatECM as a robust tool for studying ECM-driven skin disorders and for accelerating the identification of candidate therapeutic targets.