Dataset Information

Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction.

ABSTRACT:

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 (transcriptional coactivator with PDZ-binding motif) 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.

SUBMITTER: Mannion AJ

PROVIDER: S-EPMC10880945 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature

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Publications

Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction.

Mannion Aarren J AJ Zhao Honglei H Zhang Yuanyuan Y von Wright Ylva Y Bergman Otto O Roy Joy J Saharinen Pipsa P Holmgren Lars L

Arteriosclerosis, thrombosis, and vascular biology 20240201 3

<h4>Background</h4>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 repr ...[more]

PMID: 38299356

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Project description:Endothelial mechanobiology is a key consideration in the progression of vascular dysfunction, including atherosclerosis. However mechanistic connections between the clinically associated physical stimuli, vessel stiffness and shear stress, and how they interact to modulate plaque progression remain incompletely characterized. Vessel-chip systems are excellent candidates for modeling vascular mechanobiology as they may be engineered from the ground up, guided by the mechanical parameters present in human arteries and veins, to recapitulate key features of the vasculature. Here, we report extensive validation of a vessel-chip model of endothelial yes-associated protein (YAP) mechanobiology, a protein sensitive to both matrix stiffness and shearing forces and, importantly, implicated in atherosclerotic progression. Our model captures the established endothelial mechanoresponse, with endothelial alignment, elongation, reduction of adhesion molecules, and YAP cytoplasmic retention under high laminar shear. Conversely, we observed disturbed morphology, inflammation, and nuclear partitioning under low, high, and high oscillatory shear. Examining targets of YAP transcriptional co-activation, connective tissue growth factor (CTGF) is strongly downregulated by high laminar shear, whereas it is strongly upregulated by low shear or oscillatory flow. Ankyrin repeat domain 1 (ANKRD1) is only upregulated by high oscillatory shear. Verteporfin inhibition of YAP reduced the expression of CTGF but did not affect ANKRD1. Lastly, substrate stiffness modulated the endothelial shear mechanoresponse. Under high shear, softer substrates showed the lowest nuclear localization of YAP whereas stiffer substrates increased nuclear localization. Low shear strongly increased nuclear localization of YAP across stiffnesses. Together, we have validated a model of endothelial mechanobiology and describe a clinically relevant biological connection between matrix stiffness, shear stress, and endothelial activation via YAP mechanobiology.

Dataset Information

Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction.

Background

Methods

Results

Conclusions

Publications

Regulation of YAP Promotor Accessibility in Endothelial Mechanotransduction.

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