Biology subjects

Radeva, M. Y.

Publications and source records attributed to Radeva, M. Y..

3 recordsLinked to original sources

bioRxiv2025

STED/AFM as a tool to investigate mechanical and adhesive properties of migrating keratinocytes

E-cadherin is a central junctional molecule of adherens junctions that regulates epithelial integrity. In keratinocytes, wound healing critically depends on dynamic modulation of adhesion and cytoskeletal organization. Here, we applied wound healing assay and the combination of the stimulated emission depletion (STED) microscopy with the atomic force microscopy (AFM) (STED/AFM hybrid technique), to study E-cadherin binding properties during keratinocyte migration. Wound closure occurred within 6 h, an effect associated with E-cadherin accumulation at the leading edge. For location-specific binding measurements with the STED/AFM technique, we overexpressed E-cadherin in mouse keratinocytes and performed single molecule force spectroscopy measurements. Inhibition of actin polymerization abolished E-cadherin binding and further reduced overall cellular stiffness. To study adhesion mechanics during migration, we used the STED/AFM technique and performed single-molecule force spectroscopy at the leading edge of keratinocytes migrating into cell-free areas, generated by removal of two-well inserts. This approach enabled, for the first time, simultaneous measurements of single-molecule binding properties and cellular mechanistic properties in actively migrating keratinocytes. Our results revealed that E-Cad molecules present during migration exhibit binding properties comparable to those of E-Cad in stable AJs. This suggests that these molecules remain functional competent and may be readily available for rapid re-engagement in cell-cell adhesion when required. We introduce a powerful methodology to investigate single molecule binding properties in migrating cells, offering new opportunities to analyze epithelial repair at molecular resolution.

cell biology↗

bioRxiv2024

Dsg2 truncation causes a lethal barrier breakdown in mice

Inflammatory bowel diseases (IBD) such as Crohns disease (CD) have a complex aetiology with alterations of both the intestinal epithelial barrier and the IL23/IL17 immune response. Here, we investigated the role of a novel mutation in the desmosomal cadherin desmoglein 2 gene (DSG2) in the pathogenesis of IBD. DSG2 is known to regulate intestinal epithelial barrier integrity. Genetic analysis of a CD patient revealed a novel likely pathogenic DSG2 mutation leading to a truncated protein lacking part of the intracellular domain. We generated an enterocyte-specific mouse model, recapitulating the human mutation to study how the cytoplasmic truncation of Dsg2 affects intestinal barrier properties systemically. Moreover, we analysed the intestinal genetic profile in these mice and compared it to IBD patients. We describe a first CD patient with a rare mutation in the DSG2 gene causing cytoplasmic truncation with affects Dsg2 mobility. Mice with enterocyte-specific Dsg2 truncation suffered from a lethal intestinal barrier defect and presented a skewed IL17 response similar to CD patients. We identified the desmosomal cadherin Dsg2 as a regulator of the skewed IL17 response. These data indicate that desmosomes regulate inflammation similar to psoriasis which explains why the same novel immune therapies are effective for both diseases.

cell biology↗

bioRxiv2022

Apremilast prevents blistering in human epidermis by stabilization of keratinocyte adhesion in pemphigus.

Pemphigus vulgaris (PV) is a life-threatening blistering skin disease caused by autoantibodies (PV-IgG) destabilizing desmosomal adhesion. Current therapies focus on suppression of autoantibody formation and thus treatments directly stabilizing keratinocyte adhesion would fulfill an unmet medical need. We here demonstrate that apremilast, a phosphodiesterase 4 inhibitor used e.g. in psoriasis, prevents blistering in PV. Apremilast abrogated PV-IgG-induced loss of keratinocyte cohesion in ex-vivo epidermis and in vitro. This was paralleled by inhibition of keratin retraction and desmosome splitting but affected neither desmoglein (Dsg) depletion nor Dsg3 binding properties. Apremilast induced phosphorylation of plakoglobin at serine 665 - a mechanisms which is known to stabilize cardiomyocyte cohesion. Interestingly, keratinocytes phospho-deficient at this side showed altered organization of Dsg1, Dsg3 and keratin filaments and impaired adhesion, which was not rescued by apremilast. These data identified a new mechanism of desmosome regulation and propose that apremilast is protective in pemphigus by stabilizing keratinocyte cohesion.

cell biology↗