Avin Babataheri's research while affiliated with French National Centre for Scientific Research and other places

Publications (25)

Preprint
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The RAC1-WAVE-Arp2/3 signaling pathway generates branched actin networks that power lamellipodium protrusion of migrating cells. Feedback is thought to control protrusion lifetime and migration persistence, but its molecular circuitry remains elusive. Using proteomics, we identified PPP2R1A among proteins differentially associated with the WAVE com...
Article
Phagocytic cells form a first line of defense of the organism, engulfing microbial pathogens. Phagocytosis involves cell mechanical changes that are not yet well understood. Understanding these mechanical modifications promises to shed light onto the immune processes that trigger pathological complications. Previous studies showed that phagocytes u...
Article
Full-text available
In the microvasculature, blood flow-derived forces are key regulators of vascular structure and function. Consequently, the development of hydrogel-based microvessel-on-chip systems that strive to mimic the in vivo cellular organization and mechanical environment has received great attention in recent years. However, despite intensive efforts, curren...
Preprint
Full-text available
In the microvasculature, blood flow-derived forces are key regulators of vascular structure and function. Consequently, the development of hydrogel-based microvessel-on-chip systems that strive to mimic the in vivo cellular organization and mechanical environment has received great attention in recent years. However, despite intensive efforts, curr...
Article
Pericytes are mural cells of the microvasculature, recognized by their thin processes and protruding cell body. Pericytes wrap around endothelial cells and play a central role in regulating various endothelial functions, including angiogenesis and inflammation. They also serve as a vascular support and regulate blood flow by contraction. Prior revi...
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To accomplish their critical task of removing infected cells and fighting pathogens, leukocytes activate by forming specialized interfaces with other cells. The physics of this key immunological process are poorly understood, but it is important to understand them because leukocytes have been shown to react to their mechanical environment. Using an...
Preprint
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To accomplish their critical task of removing infected cells and fighting pathogens, leukocytes activate by forming specialized interfaces with other cells. Using an innovative micropipette rheometer, we show in three different cell types that when stimulated by microbeads mimicking target cells, leukocytes become up to ten times stiffer and more v...
Article
In many cell types, shape and function are intertwined. In vivo, vascular endothelial cells (ECs) are typically elongated and aligned in the direction of blood flow; however, near branches and bifurcations where atherosclerosis develops, ECs are often cuboidal and have no preferred orientation. Thus, understanding the factors that regulate EC shape...
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Full-text available
In response to engagement of surface molecules, cells generate active forces that regulate many cellular processes. Developing tools that permit gathering mechanical and morphological information on these forces is of the utmost importance. Here we describe a new technique, the Micropipette Force Probe, that uses a micropipette as a flexible cantil...
Article
We investigate the mechanical conditions leading to the rupture of the plasma membrane of an endothelial cell subjected to a local, compressive force. Membrane rupture is induced by tilted microindentation, a technique used to perform mechanical measurements on adherent cells. In this technique, the applied force can be deduced from the measured ho...
Article
T lymphocytes in the human body routinely undergo large deformations, both passively when going through narrow capillaries and actively when transmigrating across endothelial cells or squeezing through tissue. We investigate physical factors that enable and limit such deformations and explore how passive and active deformations may differ. Employin...
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Atherosclerosis is triggered by chronic inflammation of arterial endothelial cells (ECs). Because atherosclerosis develops preferentially in regions where blood flow is disturbed and where ECs have a cuboidal morphology, the interplay between EC shape and mechanotransduction events is of primary interest. In this work we present a simple microfluid...
Article
Full-text available
We have developed a simple and relatively inexpensive system to visualize adherent cells in profile while measuring their mechanical properties using microindentation. The setup allows simultaneous control of cell microenvironment by introducing a micropipette for the delivery of soluble factors or other cell types. We validate this technique again...
Article
Full-text available
Mitochondria are dynamic cell organelles that constantly undergo fission and fusion events. These dynamical processes, which tightly regulate mitochondrial morphology, are essential for cell physiology. Here we propose an elastocapillary mechanical instability as a mechanism for mitochondrial fission. We experimentally induce mitochondrial fission...
Article
We have developed a technique to directly quantify cell-substrate adhesion force using micropipette aspiration. The micropipette is positioned perpendicular to the surface of an adherent cell and a constant-rate aspiration pressure is applied. Since the micropipette diameter and the aspiration pressure are our control parameters, we have direct kno...
Article
We present a microfabricated platform that allows simultaneous application of controlled stretch/compression forces and fluid flow shear stresses during endothelial cell (EC) live-cell monitoring. Our device employs a highly flexible magnetic composite polymer (M-CP) for actuation of a flexible microchannel system. We combine our M-CP with micropat...

Citations

... A vessel can be fabricated within a hydrogel by using a sacrificial element that the surrounding hydrogel can crosslink around and, when the sacrificial element is removed, leave an empty channel in the hydrogel that mimics the vessel. This can be achieved by simply embedding a glass rod or needle in the hydrogel during gelation that is removed afterwards [176]. The wall of the channel can then be coated with basement membrane proteins that enable BMEC attachment and the formation of a functional BBB [14]. ...
... Permeable vasculature is commonly present in disease states such as tumors and edema. Figure was derived based on the following references: (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). ...
... This has implications for cell-cell interactions, as the cell with the lower rigidity spreads at the interface. Recent rheological measurements of the viscoelastic properties of T cells during activation show a 2-3 fold increase in stiffness after stimulation with an activating microbead (39). The authors also performed AFM experiments with T cell-APC conjugates and concluded that mechanical changes occur within seconds of initial contact (39). ...
... The relative contribution of these components is hard to separate [77,78]. A novel expansion of this methodology includes an additional microindenter (not shown), allowing estimation of the effective cellular viscosity and apparent Young's modulus during phagocytosis [79]. Although cytoplasmic viscosity has been implicated as an important regulator for inward motion during phagocytosis [25,39], it has so far rarely been assessed during phagocytosis. ...
... Flat PDMS substrates served as controls. In line with previous reports [11][12][13] , endothelial cells on the microgroove substrates aligned and elongated in the groove direction (labeled as the x-axis) (Fig. 1a) and exhibited long and oriented focal adhesions (FAs) positioned along the ridges (Supplementary Fig. 1) 13,14 . At confluence, HUVEC nuclei were stained with the live-cell dye Hoechst and recorded for 24 h (Supplementary Movie 1). ...
... While the mechanism by which force is translated into biochemical cues remains controversial [10][11][12] , there is evidence that early tyrosine phosphorylation events downstream of TCR engagement occur at sites where applied force is maximal 6 . Interestingly, the amount of force a T-cell applies is directly affected by the stiffness of the stimulatory substrate 4,5 . Thus, it appears that force application is mechanically coupled to the T-cell's ability to sense stiffness (mechanosensing). ...
... So the mechanical properties of cell such as viscoelasticity are regarded as the physiological fingerprints of cells [4][5][6]. Several common methods have been presented to detect the mechanical properties of cells, such as optical tweezers [7], magnetic twisting cytometry [8], micropipette aspiration [9], and atomic force microscope (AFM) [10][11][12]. The AFM alternative mapping method based on double-peak resonant spectroscopy is suggested to elaborately identify the transient-, steady-state modulus, and reciprocal of relaxation time of fixed cells, and our present theories and prediction results are expected to broaden the application of microcantilever sensors in biodetections. ...
... [3,4] The order of these forces is at pN level on our size scale, [3] whereas rupture of the endothelial cell membrane needs hundreds of nN forces. [27] The other important consideration is that the microrollers interact momentarily with endothelial cells in an in vivo scenario since their translational speeds are very high. Therefore, one can anticipate that the movement of microrollers on endothelial cells will be safe. ...
... Because the cell volume tends to change depending on the intracellular hydrostatic pressure, the total cell surface area could be a more reliable parameter of cell size 13,14,17,18 . The precise measurement of the total cell surface area is more difficult because of small microvilli or wrinkles on the cell surface in animal cells, which occupy 21-130% of the apparent cell surface area 19,20 . Recently, we developed a method to precisely measure the total cell surface area, via which cells are flattened by overlaying with an agar block, which expands the small protrusions and wrinkles present on the cell surface 21 . ...
... It should be noted that the different mechanical cues are often interdependent, underscoring the need for careful decoupling of their respective contributions. For instance, the topography of the substrate and the waviness of the EC surface modify the shear stress that the cells perceive [292][293][294] . Similarly, substrate stiffness changes the effective strain applied on the cells 281 . ...