Biology subjects

Faurobert, E.

Publications and source records attributed to Faurobert, E..

6 recordsLinked to original sources

bioRxiv2026

Letting go to hold on: loss of CCM2 disrupts endothelial force balance in cerebral cavernous malformations

Cerebral cavernous malformations (CCM) are vascular lesions characterized by impaired endothelial integrity and altered cell-cell and cell-matrix interactions. While endothelial contractility and tractions have been implicated in CCM, how these forces are transmitted and coordinated across adhesion systems remains unknown. Here, we combined genetically encoded FRET-based molecular tension sensors of vinculin and VE-cadherin with quantitative analysis of adhesion organization to dissect this force balance in CCM2-deficient endothelial monolayers. We found that CCM2 loss redistributes molecular forces, partially through ROCK-dependent contractility, across endothelial adhesions, shifting mechanical engagement from cell-cell junctions toward the cell-matrix interface. Matrix stiffness further amplifies this imbalance, as healthy endothelial cells maintain the balance between cell-cell and cell-matrix adhesions by reinforcing both in response to stiffening, whereas CCM2-deficient cells preferentially reinforce the cell-matrix interface. These findings suggest that CCM-associated matrix remodeling could reinforce an already altered mechanical state, establishing a potential feed-forward interaction between endothelial force transmission and the extracellular environment. More broadly, our results identify the CCM complex as a molecular hub controlling force balance in response to the cell mechanical environment and establish a combined tension sensing and morphology-based imaging platform for studying adhesion mechanobiology.

biophysics↗

bioRxiv2026

Endothelial gain of PIEZO/TRPV mechanosensors drives cavernous malformations

Vascular disease often begins as a failure to read mechanical force. Cerebral cavernous malformations (CCMs) are leaky, brain-invading capillary clusters that cause stroke and seizures and arise from endothelial loss of the CCM complex. They form exclusively in low-flow vessels but existing models cannot explain this selectivity. We previously established that CCM-mutant endothelium inverts its adhesive balance, weakening cell-cell junctions while building matrix-degrading adhesions. The mechanosensors imposing this switch are unknown. Here we show that the mechanosensitive Ca2+ channels PIEZO1, TRPV2 and TRPV4 are overexpressed in the endothelium of CCM lesions in a 42-patient cohort, and that lesion volume scales with their expression level. Mechanistically, PIEZO1 partners with TRPV4 to destabilise cell-cell junctions and with TRPV2 to reinforce cell-matrix adhesions; silencing TRPV4 restores junctional integrity and abolishes KLF4 induction, whereas silencing TRPV2 or inhibition with tranilast abolishes matrix degradation and invasion. In vivo, trpv4 knockdown or inhibition with GSK2798745 restores atrioventricular canal morphogenesis in ccm2-mutant zebrafish. Gain of mechanosensory channel function is thus a causal step in CCM pathogenesis, upstream of the KLF program. Combined therapeutic targeting of TRPV2 and TRPV4 with inhibitors validated in humans offers a route to therapy.

cell biology↗

bioRxiv2025

Optogenetic SH3 nanoclustering of SRC and HCK uncovers the functional specificity of these redundant kinases in macrophages.

Understanding redundancy among Src Family Kinases (SFKs) challenges how cells achieve signaling specificity using closely related enzymes, and paves the way to revisit a basic property of any cell signaling network. Optogenetic control of the adaptor properties of the most redundant SFK members, SRC and HCK, was used to examine their potential specificity in macrophages. Uncoupling their kinase and adaptor functions uncovers an unique mechanism driven by oligomerized- and SH3-dependent specific binding that enables inducing distinct signaling outputs for each kinase. OptoSRC and optoHCK probes revealed that SRC and HCK can trigger specific cellular responses, despite only supposed overlapping functions. The specificity of optoHCK even unveils a novel role in activating polarized clathrin hotspots essential for directional migration. Redundancy could be rebuilt within optoHCK through stepwise optogenetic reconstruction of adaptor modules revealing the essential role of both membrane anchoring and SH2-domain. This deconstructive approach of SFK activation elucidated the molecular basis of their shared and unique signaling activities and supports a model of cooperative functional entanglement between SFK members, rather than simple redundancy.

cell biology↗

bioRxiv2023

Force-mediated recruitment and reprogramming of healthy endothelial cells drive vascular lesion growth

Force-driven cellular interactions are known to play a critical role in cancer cell invasion, but have remained largely unexplored in the context of vascular abnormalities, partly due to a lack of suitable genetic and cellular models. One such vascular abnormality, cerebral cavernous malformation (CCM) is characterized by leaky, tumor-like vessels in the brain, where CCM mutant cells recruit wild-type cells from the surrounding endothelium to form mosaic lesions and promote lesion growth; however the mechanisms underlying this recruitment remain poorly understood. Here, we use 3D traction force microscopy in a in-vitro model of early angiogenic invasion to reveal that hyper-angiogenic CCM2-silenced endothelial cells enhance angiogenic invasion of neighboring wild-type cells through force and extracellular matrix-guided mechanisms. We show that mechanically hyperactive CCM2-silenced tips guide wild-type cells by exerting and transmitting pulling forces and by leaving degraded paths in the matrix as cues promoting invasion in a ROCKs-dependent manner. This transmission of forces is associated with a reinforcement of {beta}1 integrin-dependent adhesive sites and actin cytoskeleton in the wild-type followers. We also show that during this process wild-type cells are reprogrammed into stalk cells through activation of matrisome and DNA replication programs, eventually leading to cell proliferation. These observations unveil a novel vascular lesion growth mechanism where CCM2 mutants hijack the function of wild-type cells to fuel CCM lesion growth. By integrating biophysical computational methodologies to quantify cellular forces with advanced molecular techniques, we provide new insights in the etiology of vascular malformations, and open up avenues to study the role of cell mechanics in tissue heterogeneity and disease progression.

bioengineering↗

bioRxiv2021

CCM2 deficient endothelial cells undergo a mechano-dependent reprogramming into senescence associated secretory phenotype used to recruit endothelial and immune cells.

Cerebral Cavernous Malformations (CCM) is a cerebrovascular disease in which stacks of dilated haemorrhagic capillaries form focally in the brain. Whether and how defective mechanotransduction, cellular mosaicism and inflammation interplay to sustain the progression of CCM diseases is unknown. Here, we reveal that CCM1- and CCM2-silenced endothelial cells enter into senescence associated with secretory phenotype (SASP) that they use to invade the extracellular matrix and attract surrounding wild-type endothelial and immune cells. Further, we demonstrate that this SASP is driven by the mechanical and molecular disorders provoked by ROCKs dysfunctions. By this, we identify CCM1/2 and ROCKs as parts of a scaffold controlling senescence, bringing new insights into the emerging field of the control of aging by cellular mechanics. This discovery reconciles the dysregulated traits of CCM1/2-deficient endothelial cells into a unique mechano-dependent endothelial fate that links perturbed mechanics to microenvironment remodelling and long-range activation of endothelial and immune cells.

cell biology↗

bioRxiv2019

Molecular flux control encodes distinct cytoskeletal responses by specifying SRC signaling pathway usage.

Multi-domain signaling proteins sample numerous stimuli to coordinate distinct cellular responses. Understanding the mechanisms of their pleiotropic signaling activity requires to directly manipulate their activity of decision leading to distinct cellular responses. We developed an optogenetic probe, optoSRC, to control spatio-temporally the SRC kinase, a representative example of versatile signaling node, and challenge its ability to generate different cellular responses. Genesis of different local molecular fluxes of the same optoSRC to adhesion sites, was sufficient to trigger distinct and specific acto-adhesive responses. Collectively, this study reveals how hijacking the pleiotropy of SRC signaling by modulating in space and time subcellular molecular fluxes of active SRC kinases.

cell biology↗