Biology subjects

Runel, G.

Publications and source records attributed to Runel, G..

4 recordsLinked to original sources

bioRxiv2025

Comparative efficacy of multi micro-stimulation alveolar (MMSA) and traditional vacuum therapy on skin biomechanics integrity, and inflammation

This study compares the effects of Multi Micro-Stimulation Alveolar (MMSA) therapy and traditional vacuum therapy on human skin explants, focusing on skin elasticity, collagen organization, and inflammatory responses. Advanced imaging modalities, including Second Harmonic Generation (SHG) microscopy and Selective Plane Illumination Microscopy (SPIM), were used for in-depth analysis. MMSA therapy was found to significantly improve skin elasticity, maintain collagen structure, limit reactive oxygen species (ROS) production, and promote tissue regeneration. In contrast, traditional vacuum therapy was associated with increased collagen breakdown, higher ROS production, and diminished structural integrity of the skin. These results identify MMSA as a more effective and safer approach for non-invasive skin treatment in both cosmetic and medical contexts.

biophysics↗

bioRxiv2025

Putative interfollicular stem cells of skin epidermis possess a specific mechanical signature that evolves during aging

Skin homeostasis and self-renewal are partially maintained by interfollicular stem cells (ISCs), located in the basal layer above the dermal papillae of the dermo-epidermal junction (DEJ). Aging leads to a decline in skin renewal and a concurrent reduction in stem cell potential. It is also marked by disorganization of the extracellular matrix in both the DEJ and dermis, and flattening of the DEJ. To better understand ISC aging, new methods are needed to characterize ISCs and their environment. Since mechanical properties of cells and their substrate influence cell fate, we employed atomic force microscopy to explore whether ICSs niches and the DEJ exhibit distinct mechanical properties. Our findings reveal that ISCs possess greater stiffness than other basal cells, a mechanical signature that diminishes with age. Additionally, the DEJ beneath ISCs shows higher stiffness than under other basal cells, providing ISCs with a specific mechanical environment, which also deteriorates during aging. In vitro, sorting of ISCs based on MCSP expression effectively isolates ISCs beneath the dermal papillae, allowing the measurement of their mechanical signature and stemness potential under varying mechanical conditions. The study of ISC mechanical signatures offers a promising approach for characterizing 3D skin models and understanding defects in skin renewal and wound healing.

cell biology↗

bioRxiv2023

EASYSTIFF(R), a portable and innovative device able to separately analyze each skin compartment for the evaluation of mechanical properties.

Human skin is submitted to various factors leading to either extrinsic or intrinsic aging. In addition to inducing molecular and morphological changes, skin aging is characterized by modifications in skin biomechanical properties modifications. These modifications can be used as biomarkers to both evaluate the degree of advancement in skin aging but also to detect potential pathologies. Hence, it is from critical interest to be able to evaluate skin biomechanical properties to fully detect and monitor these alterations. Here we introduce a portable and innovative (R)device, EASYSTIFF(R), which is thought to in vivo measure stiffness properties of skin. Based on indentation principle, EASYSTIFF allows to identify both global stiffness of skin (all confounded cutaneous compartment) or compartmentalized stiffness, in which stiffness values of each compartment, i.e., the stratum corneum, the epidermis, the dermis and the hypodermis, are separately analyzed. Thus, EASYSTIFF is a complementary tool to 2D and 3D in/ex vivo model and an alternative to existing devices that measure skin mechanical properties, for assessing the effectiveness of cosmetic products, monitoring skin stiffness over time and to provide better understanding in the evolution of skin mechanical properties.

biophysics↗

bioRxiv2018

A gradient in inner pressure of germline cells controls overlaying epithelial cell morphogenesis

It is unknown how growth in one tissue impacts morphogenesis in a neighboring tissue. To address this, we used the Drosophila ovarian follicle, where a cluster of 15 nurse cells and a posteriorly located oocyte are surrounded by a layer of epithelial cells. It is known that as the nurse cells grow, the overlying epithelial cells flatten in a wave that begins in the anterior. Here, we demonstrate that an anterior to posterior gradient of decreasing cytoplasmic pressure is present across the nurse cells and that this gradient acts through TGF{beta} to control both the triggering and the progression of the wave of epithelial cell flattening. Our data indicate that intrinsic nurse cell growth is important to control proper nurse cell pressure. Finally, we reveal that nurse cell pressure and subsequent TGF{beta} activity in the StC combine to increase follicle elongation in the anterior, which is crucial for allowing nurse cell growth and pressure control. More generally, our results reveal that during development, inner cytoplasmic pressure in individual cells has an important role in shaping their neighbors. Impact StatementCell shape change depends on extrinsic forces exerted by cytoplasmic pressure in neighbouring cells.

developmental biology↗