Work

Alterations in the microenvironment of junctional epidermolysis bullosa keratinocytes: A gene expression study

Year: 2024

Type: article

Abstract: • JEB keratinocytes lacking either the integrin β4 subunit or type XVII collagen displayed similar dysregulation patterns of extracellular matrix(ECM) and focal adhesions(FAs)-associated genes, which is opposite in keratinocytes absent of the laminin β3 chain. • The hierarchy of stable adhesion in JEB keratinocytes follows the order of COL17- > ITGB4- > LAMB3-, aligning with the severity of their respective clinical manifestations. • JEB keratinocytes may act as potential initiators of the inflammatory process by expressing cytokines and chemokines, which is not ameliorated by rescuing cell adhesion. Integrin α6β4 subunits and type XVII collagen are critical transmembrane proteins involved in cell-matrix adhesion in skin, while laminin 332 serves as their ligand in the basement membrane zone (BMZ). Those proteins contribute to the composition of hemidesmosomes (HDs) and pathogenic variants in their corresponding genes cause junctional epidermolysis bullosa (JEB). Although the genotype-phenotype relationships in JEB have been extensively studied, the pathogenetic changes of extracellular matrix (ECM) and cell-matrix adhesion resulting from gene mutations remain unclear. We conducted a global unbiased transcriptome analysis using bulk RNA sequencing (RNA-seq) on selected JEB donor-derived cell lines lacking integrin β4 subunit (ITGB4-), type XVII collagen (COL17-) and laminin β3 chain (LAMB3-), respectively. Additional JEB cell lines and JEB donor skin samples were used for validation of relevant findings. Collectively, the results revealed similar dysregulation patterns of ECM and focal adhesion (FAs) associated genes in ITGB4- and COL17- cell lines, while LAMB3- cells displayed a relatively opposite tendency. Importantly, key nodes in the dysregulated network were associated with ECM proteins involved in wound healing processes. Additionally, a group of inflammatory-associated genes was disclosed to be up-regulated in JEB keratinocytes and could not be normalized by the adhesion rescue. The functional assay further revealed the hierarchy of stable adhesion among mutant cell lines COL17->ITGB4->LAMB3-, which correlates with the severity of their clinical manifestations. Our results indicated a wound healing associated ECM and inflammatory microenvironment established by JEB keratinocytes.

Source: Matrix Biology

DOI: 10.1016/j.matbio.2024.11.005