Mechanical Characterization of Murine Oocytes by Atomic Force Microscopy.

The quality of murine and human oocytes correlates to their mechanical properties, which are tightly regulated to reach the blastocyst stage after fertilization. Oocytes are nonadherent spherical cells with a diameter over 80 μm. Their mechanical properties have been studied in our lab and others using the micropipette aspiration technique, particularly to obtain the oocyte cortical tension.

Actin dynamics regulation by TTC7A/PI4KIIIα limits DNA damage and cell death under confinement.

Background: The actin cytoskeleton has a crucial role in the maintenance of the immune homeostasis by controlling various cellular processes, including cell migration. Mutations in TTC7A have been described as the cause of a primary immunodeficiency associated to different degrees of gut involvement and alterations in the actin cytoskeleton dynamics.

Objectives: This study investigates the impact of TTC7A deficiency in immune homeostasis.

Pinching the cortex of live cells reveals thickness instabilities caused by myosin II motors.

The cell cortex is a contractile actin meshwork, which determines cell shape and is essential for cell mechanics, migration, and division. Because its thickness is below optical resolution, there is a tendency to consider the cortex as a thin uniform two-dimensional layer. Using two mutually attracted magnetic beads, one inside the cell and the other in the extracellular medium, we pinch the cortex of dendritic cells and provide an accurate and time-resolved measure of its thickness.

Myosin II Activity Is Selectively Needed for Migration in Highly Confined Microenvironments in Mature Dendritic Cells.

Upon infection, mature dendritic cells (mDCs) migrate from peripheral tissue to lymph nodes (LNs) to activate T lymphocytes and initiate the adaptive immune response. This fast and tightly regulated process is tuned by different microenvironmental factors, such as the physical properties of the tissue. Mechanistically, mDCs migration mostly relies on acto-myosin flow and contractility that depend on non-muscular Myosin IIA (MyoII) activity.

Reconstitution of cell migration at a glance.

Single cells migrate in a myriad of physiological contexts, such as tissue patrolling by immune cells, and during neurogenesis and tissue remodeling, as well as in metastasis, the spread of cancer cells. To understand the basic principles of single-cell migration, a reductionist approach can be taken. This aims to control and deconstruct the complexity of different cellular microenvironments into simpler elementary constrains that can be recombined together.

Leukocyte Migration and Deformation in Collagen Gels and Microfabricated Constrictions.

In multicellular organisms, cell migration is a complex process. Examples of this are observed during cell motility in the interstitial space, full of extracellular matrix fibers, or when cells pass through endothelial layers to colonize or exit specific tissues. A common parameter for both situations is the fast adaptation of the cellular shape to their irregular landscape.

Lysosome signaling controls the migration of dendritic cells.

Dendritic cells (DCs) patrol their environment by linking antigen acquisition by macropinocytosis to cell locomotion. DC activation upon bacterial sensing inhibits macropinocytosis and increases DC migration, thus promoting the arrival of DCs to lymph nodes for antigen presentation to T cells. The signaling events that trigger such changes are not fully understood.

Mechanisms for fast cell migration in complex environments.

Cell migration depends on a combination of the cell's intrinsic capacity to move and the proper interpretation of external cues. This multistep process enables leukocytes to travel long distances in organs in just a few hours. This fast migration is partly due to the leukocytes' high level of plasticity, which helps them to adapt to a changing environment.

MENA Confers Resistance to Paclitaxel in Triple-Negative Breast Cancer.

Taxane therapy remains the standard of care for triple-negative breast cancer. However, high frequencies of recurrence and progression in treated patients indicate that metastatic breast cancer cells can acquire resistance to this drug. The actin regulatory protein MENA and particularly its invasive isoform, MENA, are established drivers of metastasis.