Exploring aortic stiffness in aging mice: a comprehensive methodological overview.

Stiffening of the vascular network is associated with the early stages of vascular aging, leading to cardiovascular disorders (hypertension), renal failures, or neurodegenerative diseases (Alzheimer's). Unfortunately, many people remain undiagnosed because diagnostic methods are either unsuitable for a large population or unfamiliar to clinicians which favor the hypertension evaluation. In preclinical research, stiffness studies are often partially conducted.

Early Alterations of Intra-Mural Elastic Lamellae Revealed by Synchrotron X-ray Micro-CT Exploration of Diabetic Aortas.

Diabetes is a major concern of our society as it affects one person out of 11 around the world. Elastic fiber alterations due to diabetes increase the stiffness of large arteries, but the structural effects of these alterations are poorly known. To address this issue, we used synchrotron X-ray microcomputed tomography with in-line phase contrast to image in three dimensions C57Bl6J (control) and db/db (diabetic) mice with a resolution of 650 nm/voxel and a field size of 1.

X-ray microtomography reveals a lattice-like network within aortic elastic lamellae.

The arterial wall consists of three concentric layers: intima, media, and adventitia. Beyond their resident cells, these layers are characterized by an extracellular matrix (ECM), which provides both biochemical and mechanical support. Elastin, the major component of arterial ECM, is present in the medial layer and organized in concentric elastic lamellae that confer resilience to the wall.

Identification of LRP-1 as an endocytosis and recycling receptor for β1-integrin in thyroid cancer cells.

LRP-1 is a large endocytic receptor mediating the clearance of various molecules from the extracellular matrix. LRP-1 was reported to control focal adhesion turnover to optimize the adhesion-deadhesion balance to support invasion. To better understand how LRP-1 coordinates cell-extracellular matrix interface, we explored its ability to regulate cell surface integrins in thyroid carcinomas.

LRP-1--CD44, a new cell surface complex regulating tumor cell adhesion.

The low-density lipoprotein receptor-related protein 1 (LRP-1) is a large endocytic receptor mediating the clearance of various molecules from the extracellular matrix. In the field of cancer, LRP-1-mediated endocytosis was first associated with antitumor properties. However, recent results suggested that LRP-1 may coordinate the adhesion-deadhesion balance in malignant cells to support tumor progression.

Epithelial protein lost in neoplasm (EPLIN) interacts with α-catenin and actin filaments in endothelial cells and stabilizes vascular capillary network in vitro.

Adherens junctions are required for vascular endothelium integrity. These structures are formed by the clustering of the homophilic adhesive protein VE-cadherin, which recruits intracellular partners, such as β- and α-catenins, vinculin, and actin filaments. The dogma according to which α-catenin bridges cadherin·β-catenin complexes to the actin cytoskeleton has been challenged during the past few years, and the link between the VE-cadherin·catenin complex and the actin cytoskeleton remains unclear.

Unraveling the distinct distributions of VE- and N-cadherins in endothelial cells: a key role for p120-catenin.

Endothelial cells express two different classical cadherins, vascular endothelial (VE) cadherin and neural (N) cadherin, having distinct functions in the vascular system. VE-cadherin is specific to endothelial adherens junctions and is strictly necessary for vascular morphogenesis. On the contrary, N-cadherin shows diffuse localization on the cell surface and interacts with mural cells for vessel stabilization.

The motor protein myosin-X transports VE-cadherin along filopodia to allow the formation of early endothelial cell-cell contacts.

Vascular endothelium (VE), the monolayer of endothelial cells that lines the vascular tree, undergoes damage at the basis of some vascular diseases. Its integrity is maintained by VE-cadherin, an adhesive receptor localized at cell-cell junctions. Here, we show that VE-cadherin is also located at the tip and along filopodia in sparse or subconfluent endothelial cells.

Structure of artificial and natural VE-cadherin-based adherens junctions.

In vascular endothelium, adherens junctions between endothelial cells are composed of VE-cadherin (vascular endothelial cadherin), an adhesive receptor that is crucial for the proper assembly of vascular structures and the maintenance of vascular integrity. As a classical cadherin, VE-cadherin links endothelial cells together by homophilic interactions mediated by its extracellular part and associates intracellularly with the actin cytoskeleton via catenins. Although, from structural crystallographic data, a dimeric structure arranged in a trans orientation has emerged as a potential mechanism of cell-cell adhesion, the cadherin organization within adherens junctions remains controversial.

Assembly and micromanipulation of Xenopus in vitro-assembled mitotic chromosomes.

Mitotic chromosomes have fascinated scientists for several decades. Despite the numerous microscopy studies, chromosome structure is, however, still poorly understood. This is due to both the high complexity of the mitotic chromosomes and the lack of other appropriate techniques suitable for studying their organization.

Nucleolin is a histone chaperone with FACT-like activity and assists remodeling of nucleosomes.

Remodeling machines play an essential role in the control of gene expression, but how their activity is regulated is not known. Here we report that the nuclear protein nucleolin possesses a histone chaperone activity and that this factor greatly enhances the activity of the chromatin remodeling machineries SWI/SNF and ACF. Interestingly, nucleolin is able to induce the remodeling by SWI/SNF of macroH2A, but not of H2ABbd nucleosomes, which are otherwise resistant to remodeling.

The mitotic chromosome is an assembly of rigid elastic axes organized by structural maintenance of chromosomes (SMC) proteins and surrounded by a soft chromatin envelope.

The structure of mitotic chromosomes is still poorly understood. Here we describe the use of a novel approach based on elasticity measurements of a single chromosome for studying the organization of these objects. The data reveal that mitotic chromosomes exhibit a non-homogenous structure consisting of rigid elastic axes surrounded by a soft chromatin envelope.