Endothelial cells (ECs) continuously sense and adapt to changes in shear stress generated by blood flow. Here, we show that the activation of the mechanosensitive channel Piezo1 by defined shear forces induces Ca entry into the endoplasmic reticulum (ER) via the ER Ca ATPase pump. This entry is followed by inositol trisphosphate receptor 2 (IPR2)-elicited ER Ca release into the cytosol. The mechanism of ER Ca release involves the generation of cAMP by soluble adenylyl cyclase (sAC), leading to IPR2-evoked Ca gating. Depleting sAC or IPR2 prevents ER Ca release and blocks EC alignment in the direction of flow. Overexpression of constitutively active Akt1 restores the shear-induced alignment of ECs lacking Piezo1 or IPR2, as well as the flow-induced vasodilation in endothelial restricted Piezo1 knockout mice. These studies describe an unknown Piezo1-cAMP-IPR2 circuit as an essential mechanism activating Akt signaling and inducing adaptive changes in ECs to laminar flow.
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http://dx.doi.org/10.1016/j.isci.2023.106661 | DOI Listing |
Front Neurol
December 2024
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Objective: This study initiated a preliminary computational fluid dynamics (CFD)-based study to investigate the relationship between quantitative hemodynamics of arteriovenous malformation (AVM) draining veins and rupture.
Methods: The quantitative hemodynamics of AVM draining veins were generated from computed tomography angiography (CTA)-based steady-state CFD models. Morphological and hemodynamic parameters were compared between the ruptured and unruptured groups.
BMC Musculoskelet Disord
December 2024
Department of Orthopaedics, Seventh People's Hospital of Shanghai University of TCM, Shanghai, 200137, China.
Introduction: The modified pedicle screw fixation (PSF) was designed to simulate an integrated framework structure to ameliorate the resistance to vertical and shearing forces of the disrupted sacroiliac complex, and the aim of this study was to compare the biomechanical characteristics of PSF and traditional lumbopelvic fixation (LPF) for the treatment of sacroiliac joint disruption.
Methods: The digital computer simulation model of an intact spine-pelvis-femur complex with main ligaments was built from clinical images. A left sacroiliac joint disruption model was mimicked by removing the concerned ligaments.
Int J Numer Method Biomed Eng
January 2025
Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
As the number of cerebral aneurysms treated with flow diverters continues to increase, it is important to understand what factors influence not only thrombus formation within the aneurysm cavity but also fibrin accumulation across the device and its associated disruption and blockage of the inflow stream. Both processes contribute to the eventual occlusion of the aneurysm or its continued patency and incomplete occlusion which may require future re-treatment. To investigate fibrin accumulation on flow diverters placed across the neck of cerebral aneurysms, a previously developed computational model that couples flow and fibrin dynamics is used in combination with experimental in vitro models of cerebral aneurysms treated with flow diverters.
View Article and Find Full Text PDFAnn Anat
December 2024
Department of Urology, Graduate School of Medicine and Dentistry, Hiroshima University School of Medicine, Hiroshima, Japan.
Background: There is little information about when and how cavernosal sinusoidal endothelia develop in the external genitalia of fetuses.
Methods: We examined histological sections of erectile tissue in 37 human fetuses (25 males and 12 females) whose gestational age (GA) ranged from 8 to 40 weeks.
Results: The sinusoidal lumen was filled with blood in the glans of the penis and clitoris at a GA of 10 to 11 weeks, and in the corpus spongiosum at a GA of 15 to 16 weeks.
Arterioscler Thromb Vasc Biol
December 2024
Department of Pediatrics (T.S., J.-R.M., Y.H.C., J.M.S., J. Kaplan, A.C., L.W., D.G., S.T., S.I., M.D., W.Y., A.L.M., M.R.).
Background: Computational modeling indicated that pathological high shear stress (HSS; 100 dyn/cm) is generated in pulmonary arteries (PAs; 100-500 µm) in congenital heart defects causing PA hypertension (PAH) and in idiopathic PAH with occlusive vascular remodeling. Endothelial-to-mesenchymal transition (EndMT) is a feature of PAH. We hypothesize that HSS induces EndMT, contributing to the initiation and progression of PAH.
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