Biology subjects

Gonzalez-Rodriguez, D.

Publications and source records attributed to Gonzalez-Rodriguez, D..

5 recordsLinked to original sources

bioRxiv2025

Interaction dynamics between epithelial cysts captured by tissue rheology

Epithelial cysts are minimal structures involved in morphogenesis. They are fluid-filled cavities surrounded by an epithelial monolayer. Cysts grow during development and their interactions shape organs. While their growth dynamics as single structures are well characterised, the physical mechanisms underlying their interaction remain poorly understood. Here we design a minimal assay of interacting cyst doublets based on microfabrication, quantitative biology, and theory to show that Madin-Darby Canine Kidney (MDCK) cyst interactions are essentially determined by the rheological properties of their epithelial monolayers. We report two phases of interaction between epithelial cysts: coalescence of cellular monolayers and lumen fusion, with similar speeds of 0.3 {micro}m/h. We modulate the distribution of interaction phenotypes by reducing cell-cell adhesion using E-cadherin knock-out MDCK cells and we report that E-cadherin depletion promotes lumen fusion. Remarkably, the dynamics of coalescence and fusion are conserved between both cell lines. To understand the conserved speeds and the effect of cell-cell adhesion, we model the mechanical behavior of cyst doublets as a complex fluid to predict a speed determined by viscosity, a stretch-dependent monolayer tension, and the adhesion energy between cells. We measure these parameters through rheological experiments using micropipette aspiration and lumen drainage, which span the full range of stretch. A key insight from this analysis is that accounting for the tensions dependence on stretch is is essential to capture the different dynamics observed during cyst interaction. Using these rheological measurements, we successfully recapitulate the conserved speed. Altogether, our results open new perspectives to understand tissue dynamics during organogenesis through simple physical arguments. Significance StatementCysts are fluid-filled cavities sur-rounded by a cellular monolayer. Interactions between cysts are important during morphogenesis, yet their governing rules are poorly understood. Here we designed a doublet assay using microfabrication to control cyst geometry and characterized their interaction dynamics. We report that speeds of coalescence and fusion between epithelial cysts are conserved even for cell lines depleted in E-cadherin, a central adhesion protein. We measured their rheological parameters by two independent methods, micropipette aspiration and laser cutting. Using a simple model and scaling arguments, we demonstrate that these parameters are sufficient to explain interaction speeds. This study sheds light on the interplay between tissue dynamics and rheology and its implication in orchestrating morphogenetic events in vitro and in vivo.

biophysics↗

bioRxiv2023

1D confinement mimicking microvessel geometry controls pericyte shape and motility

Pericytes are mural cells of the microvasculature, characterised by their elongated distinct shape. Pericytes span along the axis of the vessels they adhere to, therefore they experience extreme lateral and longitudinal confinement. Pericyte shape is key for their function during vascular regulation and their spatial distribution is established by cell migration during the embryonic stage and maintained through controlled motility in the adult. However, how pericyte morphology is associated with migration and function remains unknown. We use micropatterns to mimic pericyte adhesion to vessels, and to reproduce in vitro the shapes adopted by pericytes in vivo. We show that lateral confinement controls cell shape and produces in vivo-like phenotype. Modelling the pericyte as an incompressible linear elastic material predicts strain and shape of pericytes as a function of lateral confinement. Pericyte kinetics on both laterally confining lanes, and longitudinally constraining motifs is described by dry friction theory. Pericytes are capable of crossing gaps of different sizes. The percentage of crossings is correctly predicted by the likelihood of a fluctuating system to overcome an energy barrier. Our joint experimental and theoretical approach demonstrates the effect of in vivo-like geometrical confinement on pericyte morphology and migration which is accurately described by dry friction theory.

biophysics↗

bioRxiv2022

Caveolae govern plasma membrane mechanics to protect cells against EDIN B-induced transcellular tunnel formation and lethality from S. aureus septicaemia

Large transcellular pores elicited by bacterial mono-ADP-ribosyltransferase (mART) exotoxins inhibiting the small RhoA GTPase compromise the endothelial barrier. Recent advances in biophysical modeling point towards membrane tension and bending rigidity as the minimal set of mechanical parameters determining the nucleation and maximal size of transendothelial cell macroaperture (TEM) tunnels induced by bacterial RhoA-targeting mART exotoxins. We report that cellular depletion of caveolin-1, the membrane-embedded building block of caveolae, and depletion of cavin-1, the master regulator of caveolae invaginations, increase the number of TEMs per cell. The enhanced occurrence of TEM nucleation events correlates with a reduction of cell height, due to the increase of cell spreading and decrease of cell volume, which, together with the disruption of RhoA-driven F-actin meshwork, favor membrane apposition for TEM nucleation. Strikingly, caveolin-1 specifically controls the opening speed of TEMs leading to their dramatic 5.4-fold larger widening. Consistent with the increase of TEM density and width in siCAV1 cells, we record a higher lethality in caveolin-1-deficient mice subjected to a catalytically active mART exotoxin targeting RhoA during staphylococcal bloodstream infection. Combined theoretical modeling with independent biophysical measurements of plasma membrane bending rigidity point toward a specific contribution of caveolin-1 to membrane stiffening in addition to the role of cavin-1/caveolin-1-dependent caveolae in the control of membrane tension homeostasis.

biophysics↗

bioRxiv2022

Contractility-induced self-organization of smooth muscle cells: from multilayer cell sheets to dynamic three-dimensional clusters

Smooth muscle cells (SMCs) are mural cells that play a vital contractile function in many tissues. Abnormalities in SMC organization are associated with many diseases including atherosclerosis, asthma, and uterine fibroids. Various studies have reported that SMCs cultured on flat surfaces can spontaneously form three-dimensional clusters whose organization resembles that encountered in some of these pathological settings. Remarkably, how these structures form remains unknown. Here we combine in vitro experiments and physical modeling to show that three-dimensional clusters initiate when cellular contractile forces induce a hole in a flat SMC sheet, a process that can be modeled as the brittle fracture of a viscoelastic material. The subsequent evolution of the nascent cluster can be modeled as an active dewetting process with cluster shape evolution driven by a balance between cluster surface tension, arising from both cell contractility and adhesion, and cluster viscous dissipation. The description of the physical mechanisms governing the spontaneous emergence of these intriguing three-dimensional clusters offers insight into SMC-related disorders.

biophysics↗

bioRxiv2021

Topography-induced large-scale anti-parallel collective migration in vascular endothelium

Collective migration of vascular endothelial cells is central for embryonic development, angiogenesis, and wound closure. Although physical confinement of cell assemblies has been shown to elicit specific patterns of collective movement in various cell types, endothelial migration in vivo often occurs without confinement. Here we show that unconfined endothelial cell monolayers on microgrooved substrates that mimic the anisotropic organization of the extracellular matrix exhibit a new type of collective movement that takes the form of a periodic pattern of anti-parallel cell streams. We further establish that the development of these streams requires intact cell-cell junctions and that stream sizes are particularly sensitive to groove depth. Finally, we show that modeling the endothelial cell sheet as an active fluid with the microgrooves acting as constraints on cell orientation predicts the occurrence of the periodic anti-parallel cell streams as well as their lengths and widths. We posit that in unconfined cell assemblies, physical factors that constrain or bias cellular orientation such as anisotropic extracellular matrix cues or directed flow-derived shear forces dictate the pattern of collective cell movement.

biophysics↗