Localization, fate and interactions of Emilin‐1 in human skin

Abstract

Abstracts Objective Emilin‐1 is a versatile protein abundant in tissues where resilience and elastic recoil are prominent and interacting with components of the extracellular matrix. Still, little is known about Emilin‐1 in the skin. Therefore, we investigated Emilin‐1 in the skin, its localization, its fate upon ageing, its interactions with other proteins and the effect of its knockdown. Methods Skin explants from young or old Caucasian women, immunofluorescently labelled by anti‐Emilin‐1, anti‐Fibrillin‐1 and anti‐Elastin antibodies, were analysed using confocal microscopy. Skin explants subjected to UV‐induced skin ageing were also analysed. Colocalization of Emilin‐1 with Collagen IV, Fibrillin‐1 and Elastin was studied by multiphoton microscopy and co‐immunoprecipitation. Finally, the effect of Emilin‐1 extinction was studied by producing small interfering RNA (siRNA) knockdown fibroblasts and by analysing the outcome on selected genes. Results In skin sections from young donors, Emilin‐1 localizes similarly to Elastin and Fibrillin‐1. In the papillary dermis, it shows clear and ramified structures, perpendicular to the dermo‐epidermal junction that are reminiscent of the oxytalan fibres. In the reticular dermis, Emilin‐1 signal appears identical to that of the elastic fibres network. Upon intrinsic or UV‐induced ageing, the signal associated with Emilin‐1 is drastically reduced and disorganized. Multiphoton microscopy study shows that, as expected, Emilin‐1 colocalizes with Elastin. It also colocalizes with Collagen IV in the basement membrane and within dermal fibroblasts. Interaction of Emilin‐1 with Elastin and Collagen IV was also found by co‐immunoprecipitation. It also reveals interaction with Laminin‐5. Finally, siRNA‐mediated knockdown of EMILIN‐1 show little effect on the expression level of the 61 genes we studied. The most striking change is a downregulation of fibroblast growth factor receptor 2 that show a decrease similar to that of EMILIN‐1 itself and after 8 days a downregulation of COL6A1. Conclusion In skin, Emilin‐1 locates in the dermis, up to the basement membrane, interacting with components of the extracellular matrix but also with the anchoring complex. These interactions are important for cell adhesion, migration, proliferation and would suggest that Emilin‐1 might be important for maintaining the 3D structure of the extracellular matrix.

Inactivation of EMILIN-1 by proteolysis and secretion in small extracellular vesicles favors melanoma progression and metastasis

“…We observed that cells overexpressing EMILIN-1 had no directed migration, suggesting that its overexpression impair effective migration in melanoma cells. Previous analysis of Emillin1 expression in the skin showed that it locates in the dermis, up to the basement membrane, interacting with components of the ECM but also with the anchoring complex suggesting an important role for cell adhesion, migration, proliferation [45]. Directional cell motility is critical during inflammation, embryogenesis, and cancer metastasis [46, 47].…”

Inactivation of EMILIN-1 by Proteolysis and Secretion in Small Extracellular Vesicles Favors Melanoma Progression and Metastasis

“…We observed that some overexpressed genes belonged to proteins hyper-secreted in sEVs from B16-F1R2. Interestingly, out of several candidates we selected EMILIN-1, a protein related to ECM and lymph node remodeling [ 23 ], that was hyper-secreted in sEVs and also overexpressed at the mRNA level ( Figure 1 F, Supplementary Table S2 ).…”

“…Elastin microfibrillar interface proteins (EMILINs) constitute a four-member family of glycoproteins with a C-terminus gC1q domain typical of the gC1q/TNF superfamily members and also contain N-terminus unique cysteine-rich EMI domain [ 20 ]. EMILIN-1 has been characterized in multiple scenarios such as cell migration [ 21 ] and proliferation [ 20 ], cell migration [ 21 ], lymphatic vessel function [ 22 ] skin homeostasis [ 23 ], and cancer development [ 19 ].…”

Human amniotic epithelial cell transplantation improves scar remodeling in a rabbit model of acute vocal fold injury: a pilot study

“…EMILIN1 interacts with components of the ECM, namely fibrillin and elastin, that together assemble into a complex network of elastic fibers which plays a pivotal role in the mechanical properties of the lamina propria and the quality of phonation [ 38 , 39 ]. It also binds to components of the basement membrane, including collagen I and LN322, which are part of the anchoring complex [ 40 ]. EMILIN1 interacts with the TGFβ1 precursor complex and maintains TGFβ1 in a latent state [ 41 ] and, thereby, could suppress its mitogenic effects.…”