Morphoregulatory ADD3 underlies glioblastoma growth and formation of tumor-tumor connections.

Glioblastoma is a major unmet clinical need characterized by striking inter- and intra-tumoral heterogeneity and a population of glioblastoma stem cells (GSCs), conferring aggressiveness and therapy resistance. GSCs communicate through a network of tumor-tumor connections (TTCs), including nanotubes and microtubes, promoting tumor progression. However, very little is known about the mechanisms underlying TTC formation and overall GSC morphology.

Serialized on-grid lift-in sectioning for tomography (SOLIST) enables a biopsy at the nanoscale.

Cryo-focused ion beam milling has substantially advanced our understanding of molecular processes by opening windows into cells. However, applying this technique to complex samples, such as tissues, has presented considerable technical challenges. Here we introduce an innovative adaptation of the cryo-lift-out technique, serialized on-grid lift-in sectioning for tomography (SOLIST), addressing these limitations.

Unveiling the polarity of actin filaments by cryo-electron tomography.

The actin cytoskeleton plays a fundamental role in numerous cellular processes, such as cell motility, cytokinesis, and adhesion to the extracellular matrix. Revealing the polarity of individual actin filaments in intact cells would foster an unprecedented understanding of cytoskeletal processes and their associated mechanical forces. Cryo-electron tomography provides the means for high-resolution structural imaging of cells.

Differential dynamics of early stages of platelet adhesion and spreading on collagen IV- and fibrinogen-coated surfaces.

Upon wound formation, platelets adhere to the neighboring extracellular matrix and spread on it, a process which is critical for physiological wound healing. Multiple external factors, such as the molecular composition of the environment and its mechanical properties, play a key role in this process and direct its speed and outcome. We combined live cell imaging, quantitative interference reflection microscopy and cryo-electron tomography to characterize, at a single platelet level, the differential spatiotemporal dynamics of the adhesion process to fibrinogen- and collagen IV-functionalized surfaces.

Glycoprotein Ib clustering in platelets can be inhibited by α-linolenic acid as revealed by cryo-electron tomography.

Platelet adhesion to the sub-endothelial matrix and damaged endothelium occurs through a multi-step process mediated in the initial phase by glycoprotein Ib binding to von Willebrand factor (vWF), which leads to the subsequent formation of a platelet plug. The plant-derived ω-3 fatty acid α-linolenic acid is an abundant alternative to fish-derived n-3 fatty acids and has anti-inflammatory and antithrombotic properties. In this study, we investigated the impact of α-linolenic acid on human platelet binding to vWF under high-shear flow conditions (mimicking blood flow in stenosed arteries).

The structure of a membrane adenylyl cyclase bound to an activated stimulatory G protein.

Membrane-integral adenylyl cyclases (ACs) are key enzymes in mammalian heterotrimeric GTP-binding protein (G protein)-dependent signal transduction, which is important in many cellular processes. Signals received by the G protein-coupled receptors are conveyed to ACs through G proteins to modulate the levels of cellular cyclic adenosine monophosphate (cAMP). Here, we describe the cryo-electron microscopy structure of the bovine membrane AC9 bound to an activated G protein αs subunit at 3.

Tiopronin-Protected Gold Nanoparticles as a Potential Marker for Cryo-EM and Tomography.

Gold nanoparticles (AuNPs) and their conjugation to biological samples have numerous potential applications. When combined with cryo-electron microscopy and tomography analysis, AuNPs may provide a versatile and powerful tool to identify and precisely localize proteins even when attached to cellular components. Here, we describe a general and facile approach for the synthesis of homogeneous and stable AuNPs, which can readily be conjugated to a molecule of interest and imaged by cryo-electron tomography (cryo-ET).

Profilin 1-mediated cytoskeletal rearrangements regulate integrin function in mouse platelets.

Profilin 1–mediated cytoskeletal dynamics regulate platelet β1- and β3-integrin function and turnover. Profilin 1 deficiency in platelets impairs hemostasis and results in a marked protection from arterial thrombosis.

Morphometric analysis of spread platelets identifies integrin αβ-specific contractile phenotype.

Haemostatic platelet function is intimately linked to cellular mechanics and cytoskeletal morphology. How cytoskeletal reorganizations give rise to a highly contractile phenotype that is necessary for clot contraction remains poorly understood. To elucidate this process in vitro, we developed a morphometric screen to quantify the spatial organization of actin fibres and vinculin adhesion sites in single spread platelets.

Toward correlating structure and mechanics of platelets.

The primary physiological function of blood platelets is to seal vascular lesions after injury and form hemostatic thrombi in order to prevent blood loss. This task relies on the formation of strong cellular-extracellular matrix interactions in the subendothelial lesions. The cytoskeleton of a platelet is key to all of its functions: its ability to spread, adhere and contract.

The macromolecular architecture of platelet-derived microparticles.

Platelets are essential for hemostasis and wound healing. They are involved in fundamental processes of vascular biology such as angiogenesis, tissue regeneration, and tumor metastasis. Upon activation, platelets shed small plasma membrane vesicles termed platelet-derived microparticles (PMPs).

Surgical treatment of open globe trauma complicated with the presence of an intraocular foreign body.

Background: Open globe injuries complicated with the presence of an intraocular foreign body constitute a vision threatening condition.

Purpose: To present the results of pars plana vitrectomy in patients with intraocular foreign body.

Material And Methods: Medical records of 22 patients were analyzed.

Developments in cryo-electron tomography for in situ structural analysis.

Structural analysis of macromolecular assemblies and their remodeling during physiological processes is instrumental to defining the fundament of cellular and molecular biology. Recent advances in computational and analytical tools for cryo-electron tomography have enabled the study of macromolecular structures in their native environment, providing unprecedented insights into cell function. Moreover, the recent implementation of direct electron detectors has progressed cryo-electron tomography to a stage where it can now be applied to the reconstruction of macromolecular structures at high resolutions.

Roll, adhere, spread and contract: structural mechanics of platelet function.

Platelets are involved in life-sustaining processes such as hemostasis, wound healing, atherothrombosis and angiogenesis. Mechanical trauma to blood vessels causes platelet activation resulting in their adherence and clot formation at the damaged site, culminating in clot retraction and tissue repair. Two of the major players underlying this process are the cytoskeleton, i.

αTAT1 is the major α-tubulin acetyltransferase in mice.

Post-translational modification of tubulin serves as a powerful means for rapidly adjusting the functional diversity of microtubules. Acetylation of the ε-amino group of K40 in α-tubulin is one such modification that is highly conserved in ciliated organisms. Recently, αTAT1, a Gcn5-related N-acetyltransferase, was identified as an α-tubulin acetyltransferase in Tetrahymena and C.

Effects of gonadotropin-releasing hormone agonist/recombinant follicle-stimulating hormone versus gonadotropin-releasing hormone antagonist/recombinant follicle-stimulating hormone on follicular fluid levels of adhesion molecules during in vitro fertilization.

Objective: To compare the effects of GnRH-agonist/recombinant rFSH versus GnRH-antagonist/recombinant FSH stimulation on follicular fluid levels of soluble intercellular adhesion molecule (sICAM)-1 and vascular cell adhesion molecule-1 (sVCAM-1) during in vitro fertilization (IVF).

Design: Prospective, randomized study.

Setting: University hospital.