Biology subjects

Peghaire, C.

Publications and source records attributed to Peghaire, C..

4 recordsLinked to original sources

bioRxiv2025

A Microfluidic Blood Vessel-On-Chip Model of Thrombosis

BackgroundThrombus formation is regulated by the interplay between endothelial cells (EC), platelets and coagulation factors. However, most in vitro assays used to study thrombosis and develop anti-thrombotic therapies do not include the endothelium. ObjectiveTo develop a thrombus-on-chip model that includes endothelium and whole blood and allows for manipulation of extracellular matrix (ECM), shear stress and the addition of multiple cell types. MethodsA cylindrical vessel was created in a collagen matrix using the needle-based fabrication technique in a microfluidic device. Human umbilical vein EC (HUVEC) or endothelial colony-forming cells (ECFC) were cultured in the channel, with continuous monodirectional media turnover. Immunostaining and permeability measurement validated confluence and integrity of the monolayer. To investigate thrombosis, whole blood from healthy donors was perfused through TNF--activated or untreated EC-lined vessels. Image analysis and time-lapse microscopy were used to quantify labelled platelet adhesion and fibrin deposition. ResultsTNF- treatment resulted in increased platelet adhesion and fibrin deposition compared to control vessels. TNF-induced endothelial activation was confirmed by upregulation of adhesion molecules ICAM-1, E-selectin and tissue factor (TF). Thrombus formation in TNF- treated vessels was inhibited by an anti-TF antibody. In ECFC vessels, platelet adhesion and fibrin deposition were comparable to HUVEC, supporting feasibility of patient-based studies. ConclusionsWe developed a perfused thrombus-on-chip model that combines key elements of thrombus formation including endothelium. The model is amenable to independent control of microenvironmental stimuli, crosstalk with tissue-specific cells, and the inclusion of patients own cells and blood for precision medicine studies. ESSENTIALS- The endothelium is a key contributor to thrombosis - Standard in vitro methods to study thrombosis do not include the endothelium - We have developed a thrombus-on-a-chip model of thromboinflammation to measure live platelet adhesion and fibrin deposition on activated endothelium - Using endothelial colony forming cells (ECFC), we show that the method is suitable for patient studies with autologous endothelium and blood

bioengineering↗

bioRxiv2025

Strain Matters: The 129S1/SvlmJ Mouse Model Reveals the Genetic and Inflammatory Susceptibility to Hypertensive Complications

BackgroundHypertension is a leading cause of microvascular injury, yet the genetic determinants of organ-specific vulnerability remain poorly understood. Yest, we need good mouse models to investigate the complication of hypertension. This study investigates the role of genetic background in shaping hypertensive complications by comparing two mouse strains with divergent inflammatory responses. MethodsThree-month-old 129S1/SvlmJ and C57BL/6J mice received 600 ng/kg/min of angiotensin II (AngII) or saline. We compared the consequences of ANG2-induced blood pressure elevation on kidney function, BBB intergrity and cardiac hypertropy. Blood pressure (BP) was assessed by telemetry. Vascular injury markers in the brain, heart, kidneys, and retinas were systematically evaluated. ResultsBoth strains developed similar moderate hypertension with AngII. Only 129S1/SvlmJ mice exhibited spatial learning and memory deficits, blood-brain barrier hyperpermeability, astrocyte activation, retinal artery damage, hypertrophic cardiomyopathy, and renal podocyte lesions with urinary albumin/creatinine ratio (UACR) after AngII treatment. Transcriptomic analysis of brain microvessels highlighted strain-specific differences in gene regulation, particularly in inflammatory pathways, which may explain the higher vulnerability of 129S1/SvlmJ mice to hypertensive organ damage. These findings were supported in vivo by increased resident and perivascular macrophage recruitment in the brain of C57BL6/J mice under AngII compared to the 129S1/SvlmJ strain. ConclusionOur findings highlight the critical role of genetic background in shaping hypertensive complications. The 129S1/SvlmJ strain serves as a valuable model for dissecting the molecular mechanisms of hypertensive organ damage, emphasizing neurovascular inflammation as a potential therapeutic target. Translational PerspectiveThis study highlights the 129/Sv mouse strain as a superior translational model compared to the widely used C57BL/6J strain, which, despite being a standard in cardiovascular research, fails to reliably reproduce severe hypertensive organ complications. The 129/Sv strain closely mimics human hypertensive damage, including cerebral small vessel disease, nephropathy, cardiomyopathy, and retinopathy. Transcriptomic analysis of cerebral microvessels identifies maladaptive inflammation as a critical mechanistic driver of susceptibility. These findings underline the clinical relevance of genetic predisposition, improving risk stratification and providing a robust preclinical platform to develop targeted anti-inflammatory therapies aimed at preventing hypertension-induced end-organ damage in patients.

pathology↗

bioRxiv2024

Cerebral Small Vessel Disease genetic determinant TRIM47 controls brain homeostasis via the NRF2 antioxidant system

Cerebral small vessel disease (cSVD) is a leading cause of stroke, cognitive decline and dementia, for which no specific mechanism-based treatments are available to date. Genome-wide and whole-exome association studies previously identified robust associations of common variants at chr17q25 with cSVD features on magnetic resonance imaging, with converging bioinformatic and experimental data for a causal involvement of TRIM47. Preliminary functional evaluation of TRIM47, an ubiquitin ligase enriched in brain endothelial cells (ECs), suggested its potential role in blood brain barrier (BBB) integrity. Here, we show that TRIM47 regulates brain EC resilience and adaptive responses to oxidative stress by binding to KEAP1, stabilizing NRF2 protein levels and promoting the NRF2 antioxidant signaling pathway. In vivo, Trim47-deficient mice exhibit downregulation of NRF2 target genes, BBB dysfunction, astrogliosis and cognitive impairments. Endothelial-specific deletion of Trim47 recapitulates these phenotypes. Treatment with the NRF2 activator tert- butylhydroquinone normalized BBB integrity and cognitive function in Trim47-deficient mice, highlighting the role of endothelial TRIM47 in driving brain homeostasis through NRF2 pathway activation. This work indicates that loss of the protective TRIM47/NRF2 axis may increase the susceptibility to developing human cSVD and that targeting the TRIM47/NRF2 axis could be a promising therapeutic approach for vascular cognitive impairment and dementia.

neuroscience↗

bioRxiv2020

Lack of evidence of ACE2 expression and replicative infection by SARS-CoV-2 in human endothelial cells

A striking feature of severe COVID-19 is thrombosis in large as well as small vessels of multiple organs. This has led to the assumption that SARS-CoV-2 virus directly infects and damages the vascular endothelium. However, endothelial expression of ACE2, the cellular receptor for SARS-CoV-2, has not been convincingly demonstrated. Interrogating human bulk and single-cell transcriptomic data, we found ACE2 expression in endothelial cells to be extremely low or absent in vivo and not upregulated by exposure to inflammatory agents in vitro. Also, the endothelial chromatin landscape at the ACE2 locus showed presence of repressive and absence of activation marks, suggesting that the gene is inactive in endothelial cells. Finally, we failed to achieve infection and replication of SARS-CoV-2 in cultured human endothelial cells, which were permissive to productive infection by coronavirus 229E that uses CD13 as the receptor. Our data suggest that SARS-Cov-2 is unlikely to infect endothelial cells directly; these findings are consistent with a scenario where endothelial injury is indirectly caused by the infection of neighbouring epithelial cells and/or due to systemic effects mediated by immune cells, platelets, complement activation, and/or proinflammatory cytokines.

pathology↗