Biology subjects

Quicke, P.

Publications and source records attributed to Quicke, P..

4 recordsLinked to original sources

bioRxiv2023

Bmp9 regulates Notch signaling and the temporal dynamics of angiogenesis via Lunatic Fringe

In briefThe mechanisms regulating the signaling pathways involved in angiogenesis are not fully known. Ristori et al. show that Lunatic Fringe (LFng) mediates the crosstalk between Bone Morphogenic Protein 9 (Bmp9) and Notch signaling, thereby regulating the endothelial cell behavior and temporal dynamics of their identity during sprouting angiogenesis. HighlightsO_LIBmp9 upregulates the expression of LFng in endothelial cells. C_LIO_LILFng regulates the temporal dynamics of tip/stalk selection and rearrangement. C_LIO_LILFng indicated to play a role in hereditary hemorrhagic telangiectasia. C_LIO_LIBmp9 and LFng mediate the endothelial cell-pericyte crosstalk. C_LI Bone Morphogenic Protein 9 (Bmp9), whose signaling through Activin receptor-like kinase 1 (Alk1) is involved in several diseases, has been shown to independently activate Notch target genes in an additive fashion with canonical Notch signaling. Here, by integrating predictive computational modeling validated with experiments, we uncover that Bmp9 upregulates Lunatic Fringe (LFng) in endothelial cells (ECs), and thereby also regulates Notch activity in an inter-dependent, multiplicative fashion. Specifically, the Bmp9-upregulated LFng enhances Notch receptor activity creating a much stronger effect when Dll4 ligands are also present. During sprouting, this LFng regulation alters vessel branching by modulating the timing of EC phenotype selection and rearrangement. Our results further indicate that LFng can play a role in Bmp9-related diseases and in pericyte-driven vessel stabilization, since we find LFng contributes to Jag1 upregulation in Bmp9-stimulated ECs; thus, Bmp9-upregulated LFng results in not only enhanced EC Dll4-Notch1 activation, but also Jag1-Notch3 activation in pericytes.

developmental biology↗

bioRxiv2021

Membrane voltage fluctuations in human breast cancer cells

Cancer cells feature a resting membrane potential (Vm) that is depolarized compared to normal cells, and express active ionic conductances, which factor directly in their pathophysiological behavior. Despite similarities to excitable tissues, relatively little is known about cancer cell Vm dynamics. With high-throughput, cellular-resolution Vm imaging, we characterized Vm fluctuations of hundreds of human triple-negative breast cancer MDA-MB-231 cells and compared to non-cancerous breast epithelial MCF-10A cells. By quantifying their Dynamic Electrical Signatures (DESs) through an unsupervised machine-learning protocol, we identified four classes ranging from "noisy" to "blinking/waving". The Vm of MDA-MB-231 cells exhibited spontaneous, transient hyperpolarizations that were inhibited by the voltage-gated sodium channel blocker tetrodotoxin. The Vm of MCF-10A cells was comparatively static, but fluctuations increased following treatment with transforming growth factor-{beta}1, a canonical inducer of the epithelial-to-mesenchymal transition. These data suggest that the ability to generate Vm fluctuations is acquired during transformation and may participate in oncogenesis.

systems biology↗

bioRxiv2020

Comparing volumetric reconstruction algorithms for light field imaging of high signal-to-noise ratio neuronal calcium transients

SignificanceLight-field microscopy (LFM) enables fast, light-efficient, volumetric imaging of neuronal activity with calcium indicators. Calcium transients differ in temporal signal-to-noise ratio (tSNR) and spatial confinement when extracted from volumes reconstructed by different algorithms. AimWe evaluated the capabilities and limitations of two light-field reconstruction algorithms for calcium fluorescence imaging. ApproachWe acquired light-field image series from neurons either bulk-labeled or filled intracellularly with the red-emitting calcium dye CaSiR-1 in acute mouse brain slices. We compared the tSNR and spatial confinement of calcium signals extracted from volumes reconstructed with synthetic refocusing and Richardson-Lucy 3D deconvolution with and without total variation regularization. ResultsBoth synthetic refocusing and Richardson-Lucy deconvolution resolved calcium signals from single cells and neuronal dendrites in three dimensions. Increasing deconvolution iteration number improved spatial confinement but reduced tSNR compared to synthetic refocusing. Volumetric light-field imaging did not decrease calcium signal tSNR compared to interleaved, widefield image series acquired in matched planes. ConclusionsLFM enables high-volume rate, volumetric imaging of calcium transients in single cells (bulk-labeled), somata and dendrites (intracellular loaded). The trade-offs identified for tSNR, spatial confinement, and computational cost indicate which of synthetic refocusing or deconvolution can better realize the scientific requirements of future LFM calcium imaging applications.

bioengineering↗

bioRxiv2020

Subcellular resolution 3D light field imaging with genetically encoded voltage indicators

Light field microscopy (LFM) enables high signal-to-noise ratio (SNR), light efficient volume imaging at fast frame rates, and has been successfully applied to single-cell resolution functional neuronal calcium imaging. Voltage imaging with genetically encoded voltage indicators (GEVIs) stands to particularly benefit from light field microscopys volumetric imaging capability due to high required sampling rates, and limited probe brightness and functional sensitivity. Previous LFM studies have imaged GEVIs to track population-level interactions only in invertebrate preparations and without single cell resolution. Here we demonstrate sub-cellular resolution GEVI light field imaging in acute mouse brain slices resolving dendritic voltage signals localized in three dimensions. We characterize the effects of different light field reconstruction techniques on the SNR and signal localization and compare the SNR to fluorescence transients imaged in wide field. Our results demonstrate the potential of light field voltage imaging for studying dendritic integration and action potential propagation and backpropagation in 3 spatial dimensions.

neuroscience↗