Biology subjects

Oatley, M.

Publications and source records attributed to Oatley, M..

6 recordsLinked to original sources

bioRxiv2026

Nuclear SUN2 coordinates endothelial cell-matrix interactions to regulate blood vessel homeostasis and barrier function

Vascular endothelial cells respond to environmental forces to remodel vessels during development and to achieve homeostasis, and mis-regulated responses lead to vascular dysfunction and disease. The nucleus participates in force transduction to cell-matrix junctions via the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex that resides in the nuclear envelope, but how these forces are regulated and relayed is incompletely understood. We found that the LINC complex protein SUN2 is required for proper endothelial cell-matrix interactions that occur far from the nucleus and affect angiogenic expansion, vascular responses to flow, and barrier integrity. Endothelial cells lacking SUN2 had inappropriate flow responses and reduced expression of flow-mediated transcription factors in vitro and in vivo. Expression of several matrix and adhesion genes was reduced in SUN2-depleted cells, leading to defective extracellular matrix, dysmorphic focal adhesions resistant to dynamic turnover, and disturbed cell-matrix force distribution. Mechanistically, nuclear SUN2 affected dynamic regulation of the microtubule cytoskeleton that correlated with matrix metalloprotease-dependent barrier dysfunction. These findings indicate that nuclear SUN2 establishes and maintains blood vessel homeostasis by controlling microtubule-mediated effects on focal adhesion turnover and extracellular matrix properties, with implications for cardiovascular aging and diseases such as Marfan syndrome that affect vessel wall integrity.

cell biology↗

bioRxiv2023

HES1 and ID3 temporally regulate p27 levels and endothelial cell flow-mediated quiescence depth

BackgroundEndothelial cells regulate their cell cycle as blood vessels remodel and transition to quiescence downstream of blood flow-induced mechanotransduction. Laminar blood flow leads to quiescence, but how flow-mediated quiescence is established and maintained is poorly understood. MethodsPrimary human endothelial cells were exposed to laminar flow regimens and gene expression manipulations, and quiescence depth was analyzed via time to cell cycle re-entry after flow cessation. Mouse and zebrafish endothelial expression patterns were examined via scRNA seq analysis, and mutant or morphant fish lacking p27 were analyzed for endothelial cell cycle regulation and in vivo cellular behaviors. ResultsArterial flow-exposed endothelial cells had a distinct transcriptome, and they first entered a deep quiescence, then transitioned to shallow quiescence under homeostatic maintenance conditions. In contrast, venous-flow exposed endothelial cells entered deep quiescence early that did not change with homeostasis. The cell cycle inhibitor p27 (CDKN1B) was required to establish endothelial flow-mediated quiescence, and expression levels positively correlated with quiescence depth. p27 loss in vivo led to endothelial cell cycle upregulation and ectopic sprouting, consistent with loss of quiescence. HES1 and ID3, transcriptional repressors of p27 upregulated by arterial flow, were required for quiescence depth changes and the reduced p27 levels associated with shallow quiescence. ConclusionsEndothelial cell flow-mediated quiescence has unique properties and temporal regulation of quiescence depth that depends on the flow stimulus. These findings are consistent with a model whereby flow-mediated endothelial cell quiescence depth is temporally regulated downstream of p27 transcriptional regulation by HES1 and ID3. The findings are important in understanding endothelial cell quiescence mis-regulation that leads to vascular dysfunction and disease. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=197 SRC="FIGDIR/small/544403v2_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@1137a1forg.highwire.dtl.DTLVardef@1b6bf1dorg.highwire.dtl.DTLVardef@bd4965org.highwire.dtl.DTLVardef@11dbb9b_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIDifferent quiescence stimuli lead to distinct transcriptional and functional quiescence profiles in endothelial cells C_LIO_LIp27 is required for endothelial cell quiescence and depth is temporally regulated in a flow stimulus-dependent manner that correlates with p27 levels and flow-regulated repressors HES1 and ID3 C_LIO_LIp27 is expressed in endothelial cells according to flow magnitude in vivo and is functionally required for cell cycle regulation and sprouting in vivo C_LI

cell biology↗

bioRxiv2023

Endothelial Cell SMAD6 Balances ACVRL1/Alk1 Function to Regulate Adherens Junctions and Hepatic Vascular Development

BMP signaling is critical to blood vessel formation and function, but how pathway components regulate vascular development is not well-understood. Here we find that inhibitory SMAD6 functions in endothelial cells to negatively regulate ALK1/ACVRL1-mediated responses, and it is required to prevent vessel dysmorphogenesis and hemorrhage in the embryonic liver vasculature. Reduced Alk1 gene dosage rescued embryonic hepatic hemorrhage and microvascular capillarization induced by Smad6 deletion in endothelial cells in vivo. At the cellular level, co-depletion of Smad6 and Alk1 rescued the destabilized junctions and impaired barrier function of endothelial cells depleted for SMAD6 alone. At the mechanistic level, blockade of actomyosin contractility or increased PI3K signaling rescued endothelial junction defects induced by SMAD6 loss. Thus, SMAD6 normally modulates ALK1 function in endothelial cells to regulate PI3K signaling and contractility, and SMAD6 loss increases signaling through ALK1 that disrupts endothelial junctions. ALK1 loss-of-function also disrupts vascular development and function, indicating that balanced ALK1 signaling is crucial for proper vascular development and identifying ALK1 as a "Goldilocks" pathway in vascular biology regulated by SMAD6.

developmental biology↗

bioRxiv2021

Nuclear SUN1 stabilizes endothelial cell junctions to regulate blood vessel formation

Endothelial cells line all blood vessels, where they coordinate blood vessel formation and the blood-tissue barrier via regulation of cell-cell junctions. The nucleus also regulates endothelial cell behaviors, but it is unclear how the nucleus contributes to endothelial cell activities at the cell periphery. Here we show that the nuclear-localized LINC complex protein SUN1 regulates vascular sprouting and barrier function via effects on endothelial cell-cell junction morphology and function. Loss of murine endothelial Sun1 impaired blood vessel formation and destabilized junctions, angiogenic sprouts formed but retracted in SUN1-depleted sprouts, and zebrafish vessels lacking Sun1b had aberrant junctions and defective cell-cell connections. At the cellular level, SUN1 stabilized endothelial cell-cell junctions, promoted barrier function, and regulated contractility. Mechanistically, SUN1 depletion altered cell behaviors via the cytoskeleton without changing transcriptional profiles. Reduced peripheral microtubule density, fewer junction contacts and increased catastrophes accompanied SUN1 loss, and microtubule depolymerization phenocopied effects on junctions. Depletion of GEF-H1, a microtubule-regulated Rho activator, or the LINC complex protein nesprin-1 rescued defective junctions of SUN1-depleted endothelial cells. Thus, endothelial SUN1 regulates peripheral cell-cell junctions from the nucleus via LINC complex-based microtubule interactions that affect peripheral microtubule dynamics and Rho-regulated contractility, and this long-range regulation is important for proper blood vessel sprouting and barrier function. SUMMARYThe nuclear membrane protein SUN1 promotes blood vessel formation and barrier function by stabilizing endothelial cell-cell junctions. Communication between SUN1 and endothelial cell junctions relies upon proper microtubule dynamics and Rho signaling far from the nucleus, revealing long-range cellular communication from the nucleus to the cell periphery that is important for vascular development and function.

cell biology↗

bioRxiv2019

Single-cell atlas of major haematopoietic tissues sheds light on blood cell formation from embryonic endothelium

The Yolk Sac (YS) and Aorta-Gonad-Mesonephros (AGM) are two major haematopoietic regions during embryonic development. Interestingly, AGM is the only one generating haematopoietic stem cells (HSCs). To identify the difference between AGM and YS, we compared them using single-cell RNA sequencing between 9.5 and 11.5 days of mouse embryonic development and identified cell populations using CONCLUS, a new computational tool. The AGM was the only one containing neurons and a specific mesenchymal population, while the YS major component was an epithelial population expressing liver marker genes. In addition, the YS contained a major endothelial population expressing Stab2, a hyaluronan receptor, also highly expressed by liver endothelium. We demonstrated that the YS haematopoietic potential was restricted to Stab2-negative cells and that ectopic expression of Stab2 could reduce blood cell formation from endothelium. Our results indicate that the AGM is a tissue more favourable to HSCs development than the YS because of its microenvironment and the nature of its endothelial cells.

developmental biology↗

bioRxiv2018

Single-cell transcriptomics identifies CD44 as a new marker and regulator of haematopoietic stem cells development

The endothelial to haematopoietic transition (EHT) is the process whereby haemogenic endothelium differentiates into haematopoietic stem and progenitor cells (HSPCs). The intermediary steps of this process are unclear, in particular the identity of endothelial cells that give rise to HSPCs is unknown. Using single-cell transcriptome analysis and antibody screening we identified CD44 as a new marker of EHT enabling us to isolate robustly the different stages of EHT in the aorta gonad mesonephros (AGM) region. This allowed us to provide a very detailed phenotypical and transcriptional profile for haemogenic endothelial cells, characterising them with high expression of genes related to Notch signalling, TGFbeta/BMP antagonists (Smad6, Smad7 and Bmper) and a downregulation of genes related to glycolysis and the TCA cycle. Moreover, we demonstrated that by inhibiting the interaction between CD44 and its ligand hyaluronan we could block EHT, identifying a new regulator of HSPC development.

developmental biology↗