Disturbed flow increases endothelial inflammation and permeability via a Frizzled-4-β-catenin-dependent pathway

Rickman, Matthew; Ghim, Mean; Pang, Kuin Tian; Rocha, Ana Cristina von Huelsen; Drudi, Elena M; Sureda-Vives, Macià; Ayoub, Nicolas; Tajadura-Ortega, Virginia; George, Sarah J.; Weinberg, Peter D.; Warboys, Christina M.

doi:10.1242/jcs.260449

Cited by 3 publications

(2 citation statements)

References 65 publications

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“…37 Disruption and reduction in VE-Cadherin expression under oscillatory conditions hence suggesta possible redistribution of gap junctions and cytoskeletal proteins that can compromise the monolayer integrity and increase the membrane permeability. 42 Our data suggest that redistribution of cytoskeletal proteins due to bidirectional oscillatory flows mayalterthe membrane permeability and tractional stresses,controlled by ventral stress fibers, to change cell-substrate adhesions. A measurement of the monolayer permeability alone may not represent changes in the mechanobiological behaviors of endothelial cell monolayers.…”

Section: Ve-cadherin Disruptions Are Augmented In Monolayers Under Bi...mentioning

confidence: 69%

Endothelial mechanobiology under controlled disturbed flows

Paddillaya,

Mahulkar,

Arakeri

et al. 2023

Preprint

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Early atherosclerotic lesions often develop in arterial bifurcations and curvatures that experience complex disturbed flows. Lab-on-chip devices primarily adopt laminar unidirectional and oscillatory flows to characterize endothelial mechanobiology and test therapeutics. Such flows do not reproduce the time-varying, bidirectional, and complicated shear patterns on arterial walls. We fabricated an endothelium-on-chip device and developed a semi-analytical model to produce any prescribed wall shear pattern characterized by a shear rosette. We quantified responses of Human Aortic Endothelial Cell (HAEC) monolayers subjected to unidirectional laminar (Uni-L) and oscillatory (Uni-O) flows in straight microfluidic channels, and a circular shear rosette (Bi-O), defined by bidirectional oscillatory flows, in the new device. Immunofluorescence results show well-defined stress fibers and VE-cadherin under laminar flows. Cells were more cuboidal with significantly larger nuclear areas in the device as compared to other groups. Lamin A/C disruption and heterochromatin reorganization were evident in nuclei of cells in the Bi-O group but were absent in the Uni-L and No-flow control groups. Cells showed significantly elevated actin, VE-cadherin, inflammatory NF-kB, and lamin expressions in the device compared to other groups. A device to create controlled disturbed flows offers a platform to assess mechanobiology, has significant potential in personalized medicine, and reduces reliance on animal trials.

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Section: Ve-cadherin Disruptions Are Augmented In Monolayers Under Bi...mentioning

confidence: 69%

Endothelial mechanobiology under controlled disturbed flows

Paddillaya,

Mahulkar,

Arakeri

et al. 2023

Preprint

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“…Laminar and disturbed flow was generated using orbital flow as described previously 5 , 22 using a Rotamax 120 (Heidolph) rotating platform placed in a cell culture incubator at 37 °C. HUVECs were seeded to 6-well plates with 2 mL of culture medium and orbitally shaken at 150 rpm for the indicated time periods before lysates were harvested as described by Rickman et al, 22 collecting from the periphery and center of the wells for laminar and disturbed flow, respectively.…”

Section: Methodsmentioning

confidence: 99%

Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction

Mannion,

Zhao,

Zhang

et al. 2024

ATVB

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BACKGROUND: Endothelial cells are constantly exposed to mechanical forces in the form of fluid shear stress, extracellular stiffness, and cyclic strain. The mechanoresponsive activity of YAP (Yes-associated protein) and its role in vascular development are well described; however, whether changes to transcription or epigenetic regulation of YAP are involved in these processes remains unanswered. Furthermore, how mechanical forces are transduced to the nucleus to drive transcriptional reprogramming in endothelial cells is poorly understood. The YAP target gene, AmotL2 (angiomotin-like 2), is a junctional mechanotransducer that connects cell-cell junctions to the nuclear membrane via the actin cytoskeleton. METHODS: We applied mechanical manipulations including shear flow, stretching, and substrate stiffness to endothelial cells to investigate the role of mechanical forces in modulating YAP transcription. Using in vitro and in vivo endothelial depletion of AmotL2, we assess nuclear morphology, chromatin organization (using transposase-accessible chromatin sequencing), and whole-mount immunofluorescent staining of the aorta to determine the regulation and functionality of YAP. Finally, we use genetic and chemical inhibition to uncouple the nuclear-cytoskeletal connection to investigate the role of this pathway on YAP transcription. RESULTS: Our results reveal that mechanical forces sensed at cell-cell junctions by the YAP target gene AmotL2 are directly involved in changes in global chromatin accessibility and activity of the histone methyltransferase EZH2, leading to modulation of YAP promotor activity. Functionally, shear stress–induced proliferation of endothelial cells in vivo was reliant on AmotL2 and YAP/TAZ expression. Mechanistically, uncoupling of the nuclear-cytoskeletal connection from junctions and focal adhesions led to altered nuclear morphology, chromatin accessibility, and YAP promotor activity. CONCLUSIONS: Our findings reveal a role for AmotL2 and nuclear-cytoskeletal force transmission in modulating the epigenetic and transcriptional regulation of YAP to maintain a mechano-enforced positive feedback loop of vascular homeostasis. These findings may offer an explanation as to the proinflammatory phenotype that leads to aneurysm formation observed in AmotL2 endothelial deletion models.

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Wnt7a Decreases Brain Endothelial Barrier Function Via β-Catenin Activation

Manukjan,

Chau,

Caiment

et al. 2023

Mol Neurobiol

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The blood-brain barrier consists of tightly connected endothelial cells protecting the brain’s microenvironment from the periphery. These endothelial cells are characterized by specific tight junction proteins such as Claudin-5 and Occludin, forming the endothelial barrier. Disrupting these cells might lead to blood-brain barrier dysfunction. The Wnt/β-catenin signaling pathway can regulate the expression of these tight junction proteins and subsequent barrier permeability. The aim of this study was to investigate the in vitro effects of Wnt7a mediated β-catenin signaling on endothelial barrier integrity. Mouse brain endothelial cells, bEnd.3, were treated with recombinant Wnt7a protein or XAV939, a selective inhibitor of Wnt/β-catenin mediated transcription to modulate the Wnt signaling pathway. The involvement of Wnt/HIF1α signaling was investigated by inhibiting Hif1α signaling with Hif1α siRNA. Wnt7a stimulation led to activation and nuclear translocation of β-catenin, which was inhibited by XAV939. Wnt7a stimulation decreased Claudin-5 expression mediated by β-catenin and decreased endothelial barrier formation. Wnt7a increased Hif1α and Vegfa expression mediated by β-catenin. However, Hif1α signaling pathway did not regulate tight junction proteins Claudin-5 and Occludin. Our data suggest that Wnt7a stimulation leads to a decrease in tight junction proteins mediated by the nuclear translocation of β-catenin, which hampers proper endothelial barrier formation. This process might be crucial in initiating endothelial cell proliferation and angiogenesis. Although HIF1α did not modulate the expression of tight junction proteins, it might play a role in brain angiogenesis and underlie pathogenic mechanisms in Wnt/HIF1α signaling in diseases such as cerebral small vessel disease.

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Disturbed flow increases endothelial inflammation and permeability via a Frizzled-4-β-catenin-dependent pathway

Cited by 3 publications

References 65 publications

Endothelial mechanobiology under controlled disturbed flows

Endothelial mechanobiology under controlled disturbed flows

Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction

Wnt7a Decreases Brain Endothelial Barrier Function Via β-Catenin Activation

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