T Cells Enhance Tissue Complexity and Function to Study Fibrosis in 3D Skin-Like Tissue Models.

Area of Science:

• Biomedical Engineering
• Immunology
• Dermatology

Background:

• Fibrosis, characterized by altered tissue structure and function, involves complex interactions between inflammatory cells, myofibroblasts, and extracellular matrix (ECM).
• T cells are implicated in tissue fibrosis, but their precise mechanisms in modulating cellular interactions to activate fibrogenesis remain unclear.
• Conventional monolayer cell cultures fail to replicate the intricate tissue complexity and cellular heterogeneity of fibrotic environments, necessitating more predictive models.

Purpose of the Study:

• To develop and validate a 3D skin-like tissue model incorporating human T cells for studying fibrotic diseases.
• To investigate the role of T cells in the pathogenesis of tissue fibrosis using this novel 3D model.
• To provide a more predictive platform for preclinical drug screening and mechanistic studies of fibrosis.

Main Methods:

• Construction of 3D skin-like tissues using autologous or nonautologous T cells, fibroblasts, macrophages, and keratinocytes.
• Analysis of tissue structure, cell viability, and function using tissue analysis and single-cell RNA sequencing (scRNA-seq).
• Enzyme-linked immunosorbent assay (ELISA) to measure cytokine production (e.g., IL-6) and assessment of fibroblast activation markers.

Main Results:

• The 3D skin-like tissues exhibited normal distribution of epithelial differentiation and proliferation markers.
• T cells within the tissues were viable and functional, evidenced by elevated IL-6 production and scRNA-seq data.
• Single-cell RNA sequencing identified five distinct T cell subpopulations: CD8 T cells, proliferating CD4 T cells, activated CD4 T cells, naïve CD4 T cells, and Th17 CD4 T cells.

Conclusions:

• The fabrication of complex 3D tissues represents a significant advancement for studying fibrosis using tissue engineering approaches.
• This 3D model offers a valuable platform for understanding T cell roles in the fibrotic extracellular matrix (ECM) environment and fibroblast interactions.
• Insights gained from this model can facilitate the development of novel therapeutic strategies to reverse fibrosis and restore normal tissue and organ function in diseases like scleroderma (SSc), idiopathic pulmonary fibrosis, and liver and kidney fibrosis.