Biology subjects

Pantazis, P.

Publications and source records attributed to Pantazis, P..

5 recordsLinked to original sources

bioRxiv2026

Fluid shear magnitude, mechanical history and actin-sensitive coupling shape Piezo1 signalling

Mechanical forces shape cell behaviour, yet how Piezo1-associated responses encode force magnitude, recent mechanical history and cytoskeletal context under repeated fluid shear remains unclear. We combined defined fluid shear stress (FSS) with GenEPi, a genetically encoded reporter of Piezo1-proximal Ca2+ entry, in engineered XLGenEPi-HEK293T monolayers to resolve mechanically evoked responses at single-cell and population scales. GenEPi responses increased with FSS magnitude but showed diminishing response gain at higher shear. Repeated submaximal FSS produced history-dependent attenuation and reduced temporal coordination, with higher FSS accelerating the early phase of attenuation. Low-dose Latrunculin A, without significantly reducing bulk F-actin abundance, converted sustained FSS-evoked signalling into a brief, decay-dominated response while largely preserving peak responses to Yoda1. These findings show that Piezo1-associated signalling is shaped over minutes by force magnitude, recent mechanical history and actin-sensitive mechanical coupling, providing a quantitative framework for understanding mechanotransduction under sustained and repeated mechanical stimulation.

biophysics↗

bioRxiv2023

Hyperspectral Oblique Plane Microscopy

Spontaneous Raman imaging has emerged as powerful label-free technique for investigating the molecular composition of biological specimens. Although Raman imaging can facilitate understanding of complex biological phenomena in vivo, current imaging modalities are limited in speed and sample compatibility. Here, we introduce a single-objective light-sheet microscope, named{lambda} -OPM, which records Raman images on a timescale of minutes to milliseconds. To demonstrate its function, we use{lambda} -OPM to map and identify micro-plastic particles based on their Raman spectral characteristics. In live zebrafish embryos, we show that{lambda} -OPM can capture wound dynamics at five-minute intervals, revealing rapid changes in cellular and extracellular matrix composition in the wounded region. Finally, we use{lambda} -OPM to obtain Raman scattering maps of a zebrafish embryos beating heart at an effective 28 frames per second, recording compositional changes at different points in the cardiac cycle.

bioengineering↗

bioRxiv2019

Biodegradable harmonophores for targeted high-resolution in vivo tumor imaging

Optical imaging probes have played a major role in detecting and monitoring of a variety of diseases1. In particular, nonlinear optical imaging probes, such as second harmonic generating (SHG) nanoprobes, hold great promise as clinical contrast agents, as they can be imaged with little background signal and unmatched long-term photostability2. As their chemical composition often includes transition metals, the use of inorganic SHG nanoprobes can raise long-term health concerns. Ideally, contrast agents for biomedical applications should be degraded in vivo without any long-term toxicological consequences to the organism. Here, we developed biodegradable harmonophores (bioharmonophores) that consist of polymer-encapsulated, self-assembling peptides that generate a strong SHG signal. When functionalized with tumor cell surface markers, these reporters can target single cancer cells with high detection sensitivity in zebrafish embryos in vivo. Thus, bioharmonophores will enable an innovative approach to cancer treatment using targeted high-resolution optical imaging for diagnostics and therapy.

bioengineering↗

bioRxiv2019

GenEPi: Piezo1-based fluorescent reporter for visualizing mechanical stimuli with high spatiotemporal resolution

Mechanosensing is a ubiquitous process to translate external mechanical stimuli into biological responses during development, homeostasis, and disease. However, non-invasive investigation of cellular mechanosensing in complex and intact live tissue remains challenging. Here, we developed GenEPi, a genetically-encoded fluorescent intensiometric reporter for mechanical stimuli based on Piezo1, an essential mechanosensitive ion channel found in vertebrates. We show that GenEPi has high specificity and spatiotemporal resolution for Piezo1-dependent mechanical stimuli, exemplified by resolving repetitive mechanical stimuli of spontaneously contracting cardiomyocytes within microtissues, in a non-invasive manner.

cell biology↗

bioRxiv2017

High fidelity lineage tracing in mouse pre-implantation embryos using primed conversion of photoconvertible proteins

Accurate lineage reconstruction of mammalian pre-implantation development is essential for inferring the earliest cell fate decisions of mammalian development. Lineage tracing using global labeling techniques is complicated by increasing cell density and rapid embryo rotation, impeding automatic alignment and rendering accurate cell tracking of obtained four-dimensional imaging data sets highly challenging. Here, we exploit the advantageous properties of primed convertible fluorescent proteins (pr-pcFPs) to simultaneously visualize the global green and the photoconverted red population to minimize tracking uncertainties over prolonged time windows. Confined primed conversion of H2B-pr-mEosFP labeled nuclei combined with light-sheet imaging greatly facilitates segmentation, classification, and tracking of individual nuclei from the 4-cell stage up to the blastocyst. Using green and red labels as fiducial markers, we computationally correct for rotational and translational drift and accomplish high fidelity lineage tracing combined with a reduced data size - addressing majors concerns in the field of volumetric embryo imaging.

developmental biology↗