Biology subjects

Iolascon, A.

Publications and source records attributed to Iolascon, A..

5 recordsLinked to original sources

bioRxiv2026

Label-Free Nucleoli Measurement by 3D Holo-Tomographic Flow Cytometry Using Biolens Phase Compensation

Holo-Tomographic Flow Cytometry (HTFC) holds the potential to transform cellular research and clinical screening through 3D label-free quantitative phase imaging (QPI) of flowing single cells. However, it has been limited by insufficient intracellular specificity in 3D refractive index (RI) distributions, since suspended cells act as highly aberrating spherical biolenses obscuring internal structures. Here, we show the Biolens Phase Compensation (BPC), a method that corrects phase aberrations in 2D QPI projections to transform the 3D RI tomogram. Working within this new 3D pseudo-RI space demonstrates for the first time the extraction of nucleoli in HTFC. Extensive validation against 2D fluorescence flow cytometry and 3D confocal microscopy demonstrates that BPC achieves reliable intranuclear specificity. Using statistically significant single-cell analysis, we provide multiplexed quantitative 3D measurements of nested intracellular compartments (cytoplasm, nucleoplasm, nucleoli). This approach extends label-free HTFC toward capabilities of gold-standard Fluorescence Microscopy, overcoming its well-known drawbacks in intracellular and intranuclear staining.

biophysics↗

bioRxiv2025

Holotomography-driven learning for in-silico staining of single cells in flow cytometry avoiding co-registration

Virtual staining is the current state-of-the-art computational technique to cleverly enhance intracellular specificity in unstained biological samples by using convolutional neural networks (CNNs) trained on co-registered pairs of unstained/stained images. While effective, this approach suffers from unpredictable biases inherent to fluorescence microscopy and encounters challenges when applied to flow cytometry data as it would require accurate co-registration on a huge number of images. Here, we present a novel method that exploits for the first time a Holotomography-driven learning to completely eliminate the need for co-registration. We demonstrate that training a CNN on a stain-free dataset of 3D refractive index tomograms of flowing cells elegantly unlocks stain-free intracellular specificity in quantitative phase imaging flow cytometry. This breakthrough, by circumventing the critical co-registration bottleneck, opens unprecedented perspectives for label-free, high-throughput imaging flow cytometry, offering a powerful new paradigm for advanced 2D and 3D single-cell analysis.

biophysics↗

bioRxiv2021

Stain-free nucleus identification in holographic learning flow cyto-tomography

Quantitative Phase Imaging (QPI) has gained popularity because it can avoid the staining step, which in some cases is difficult or impossible. However, QPI does not provide the well-known specificity to various parts of the cell (e.g., organelles, membrane). Here we show a novel computational segmentation method based on statistical inference that bridges the gap between the specificity of Fluorescence Microscopy (FM) and the label-free property of QPI techniques to identify the cell nucleus. We demonstrate application to stain-free cells reconstructed through the holographic learning and in flow cyto-tomography modality. In particular, by means of numerical simulations and two cancer cell lines, we demonstrate that the nucleus-like regions can be accurately distinguished within the stain-free tomograms. We show that our experimental results are consistent with confocal FM data and microfluidic cytofluorimeter outputs. This is a significant step towards extracting the three-dimensional (3D) intracellular specificity directly from the phase-contrast data in a typical flow cytometry configuration.

bioengineering↗

bioRxiv2020

Genetic analysis of the novel SARS-CoV-2 host receptor TMPRSS2 in different populations.

The infection coronavirus disease 2019 (COVID-19) is caused by a virus classified as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). At cellular level, virus infection initiates with binding of viral particles to the host surface cellular receptor angiotensin converting enzyme 2 (ACE2). SARS-CoV-2 engages ACE2 as the entry receptor and employs the cellular serine protease 2 (TMPRSS2) for S protein priming. TMPRSS2 activity is essential for viral spread and pathogenesis in the infected host. Understanding how TMPRSS2 protein expression in the lung varies in the population could reveal important insights into differential susceptibility to influenza and coronavirus infections. Here, we systematically analyzed coding-region variants in TMPRSS2 and the eQTL variants, which may affect the gene expression, to compare the genomic characteristics of TMPRSS2 among different populations. Our findings suggest that the lung-specific eQTL variants may confer different susceptibility or response to SARS-CoV-2 infection from different populations under the similar conditions. In particular, we found that the eQTL variant rs35074065 is associated with high expression of TMPRSS2 but with a low expression of the interferon (IFN)-/{beta}-inducible gene, MX1, splicing isoform. Thus, these subjects could account for a more susceptibility either to viral infection or to a decrease in cellular antiviral response.

genetics↗

bioRxiv2018

Fyn Is Involved In Erythropoietin Signaling Pathway And Interfaces Oxidation To Regulate Erythropoiesis

Erythropoiesis is a complex multistep process responsible of the production of circulating mature erythrocytes and involved the production of reactive oxygen species (ROS) during erythroid differentiation. Here, we document that Fyn, a Src-family-kinase, participates in erythropoietin (EPO) signaling pathway, by the reducing extent of Tyr-phosphorylation of EPO-R and by decreasing STAT5 activity. The importance of Fyn in EPO cascade is also supported by the increased sensitivity of Fyn-/- mice to stress erythropoiesis. Fyn -/- mouse erythroblasts adapt to the induced stress by the activation of the redox-related-transcription-factor Nrf2. However, the absence of the Nrf2 physiologic repressor Fyn resulted in the persistent activation of Nrf2 and accumulation of non-functional proteins. This is paralleled by ROS induced over-activation of Jak2-Akt-mTOR pathway and repression of autophagy and perturbation of lysosomal-clearance during Fyn -/- reticulocyte maturation. Treatment with Rapamycin, a mTOR inhibitor and autophagy activator, ameliorates Fyn-/- mouse baseline erythropoiesis and restored the erythropoietic response to phenylhydrazine. Taken together these findings have enabled to identify the novel multimodal action of Fyn in the developmental program of erythropoiesis.

cell biology↗