Biology subjects

Chioccioli, M.

Publications and source records attributed to Chioccioli, M..

7 recordsLinked to original sources

bioRxiv2022

Spatiotemporal coordination of stem cell behavior following alveolar injury

Tissue repair requires a highly coordinated cellular response to injury. In the lung, alveolar type 2 (AT2) cells act as stem cells and can replace both themselves and alveolar type 1 cells (AT1); however, the complex orchestration of AT2 stem cell activity following lung injury is poorly understood owing to the inability of tracking individual stem cells and their dynamic behavior over time. Here, we apply live time lapse imaging to ex vivo mouse precision cut lung slice (PCLS) culture and in vivo mouse lung to track individual GFP-labeled AT2 cells following induction of alveolar injury by bleomycin. We observe highly dynamic movement of AT2 cells, including migration within and between alveoli. To map the dynamic evolution of AT2 cell behavior, we introduce Live Cell Encoder (LCE-PHATE), a novel method for converting static snapshots from time lapse imaging into single points representative of entire, dynamic cellular trajectories. Applying LCE-PHATE, we observe the emergence of at least three distinct morphokinetic AT2 cell states associated with AT2 stem cell injury response. Finally, small molecule-based inhibition of Rho-associated protein kinase (ROCK) pathway significantly reduced motility of AT2 stem cells following injury and reduced expression of Krt8, a marker of intermediate progenitor cells. Together, our results uncover motility of alveolar stem cells as a new injury response mechanism in the lung and reveal properties of stem cell motility at high cellular resolution.

cell biology↗

bioRxiv2022

Adaptive phototaxis of Chlamydomonas and the evolutionary transition to multicellularity in Volvocine green algae

A fundamental issue in biology is the nature of evolutionary transitions from unicellular to multicellular organisms. Volvocine algae are models for this transition, as they span from the unicellular biflagellate Chlamydomonas to multicellular species of Volvox with up to 50,000 Chlamydomonas-like cells on the surface of a spherical extracellular matrix. The mechanism of phototaxis in these species is of particular interest since they lack a nervous system and intercellular connections; steering is a consequence of the response of individual cells to light. Studies of Volvox and Gonium, a 16-cell organism with a plate-like structure, have shown that the flagellar response to changing illumination of the cellular photosensor is adaptive, with a recovery time tuned to the rotation period of the colony around its primary axis. Here, combining high-resolution studies of the flagellar photoresponse with 3D tracking of freely-swimming cells, we show that such tuning also underlies phototaxis of Chlamydomonas. A mathematical model is developed based on the rotations around an axis perpendicular to the flagellar beat plane that occur through the adaptive response to oscillating light levels as the organism spins. Exploiting a separation of time scales between the flagellar photoresponse and phototurning, we develop an equation of motion that accurately describes the observed photoalignment. In showing that the adaptive time scale is tuned to the organisms rotational period across three orders of magnitude in cell number, our results suggest a unified picture of phototaxis in green algae in which the asymmetry in torques that produce phototurns arise from the individual flagella of Chlamydomonas, the flagellated edges of Gonium and the flagellated hemispheres of Volvox.

biophysics↗

bioRxiv2022

Saracatinib, a Selective Src Kinase Inhibitor, Blocks Fibrotic Responses in In Vitro, In Vivo and Ex Vivo Models of Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and often fatal disorder. Two FDA approved anti-fibrotic drugs, nintedanib and pirfenidone, slow the rate of decline in lung function, but responses are variable and side effects are common. Using an in-silico data-driven approach, we identified a robust connection between the transcriptomic perturbations in IPF disease and those induced by saracatinib, a selective Src kinase inhibitor, originally developed for oncological indications. Based on these observations, we hypothesized that saracatinib would be effective at attenuating pulmonary fibrosis. We investigated the anti-fibrotic efficacy of saracatinib relative to nintedanib and pirfenidone in three preclinical models: (i) in vitro in normal human lung fibroblasts (NHLFs); (ii) in vivo in bleomycin and recombinant adenovirus transforming growth factor-beta (Ad-TGF-{beta}) murine models of pulmonary fibrosis; and (iii) ex vivo in precision cut lung slices from these mouse models. In each model, the effectiveness of saracatinib in blocking fibrogenic responses was equal or superior to nintedanib and pirfenidone.

systems biology↗

bioRxiv2021

A lung targeted miR-29 Mimic as a Therapy for Pulmonary Fibrosis

microRNAs are non-coding RNAs that negatively regulate gene networks. Previously, we reported a systemically delivered miR-29 mimic MRG-201 that reduced fibrosis in animal models, but at doses prohibiting clinical translation. Here, we generated MRG-229, a next-gen miR-29 mimic with improved chemical stability, conjugated with the internalization moiety BiPPB (PDGFbetaR-specific bicyclic peptide). In TGF-b-treated human lung fibroblasts and precision cut lung slices, MRG-229 decreased COL1A1 and ACTA2 gene expression and reduced collagen production. In bleomycin-treated mice, intravenous or subcutaneous delivery of MRG-229 downregulated profibrotic gene programs at doses more than ten-fold lower than the original compound. In rats and non-human primates, and at clinically relevant doses, MRG-229 was well tolerated, with no adverse findings observed. In human peripheral blood decreased mir-29 concentrations were associated with increased mortality in two cohorts potentially identified as a target population for treatment. Collectively, our results provide support for the development of MRG-229 as a potential therapy in humans with IPF. One Sentence SummaryOne Sentence Summary: A stabilized, next-generation miR-29 mimic has been developed that demonstrates efficacy at commercially viable doses with a robust safety margin in non-human primates.

molecular biology↗

bioRxiv2019

A How-To guide to: Quantitative high-speed video profiling to discriminate between variants of primary ciliary dyskinesia

This document presents detailed steps to analysing the waveforms of beating cilia, measured in high speed video microscopy. We show that in the case of PCD caused by mutations in DNAH11 and HYDIN the classification by a handful of parameters describing ciliary dynamics allows to distinguish the genotype, as well as (much more easily) distinguishing healthy from PCD samples. This document is intended to complement the brief highlight (1) and presents the details of the datasets used in that letter.

cell biology↗

bioRxiv2018

An Adaptive Flagellar Photoresponse Determines the Dynamics of Accurate Phototactic Steering in Chlamydomonas

Our understanding of phototaxis of biflagellates stems almost exclusively from the model alga Chlamydomonas reinhardtii, via studies of its flagella, light-sensor and steering. However, no comprehensive model linking all these aspects of its physiology and behavior has been constructed and tested experimentally. Here, we develop such a mathematical model by coupling an adaptive flagellar photoresponse to rigid-body dynamics tailored to details of flagellar beating, and corroborate it with experimental data - at the flagellar and tactic levels - to explain the accurate phototactic steering of this alga. We experimentally validate the hypothesized adaptive flagellar photoresponse using high spatio-temporal resolution methodology on immobilized cells, and corroborate the predicted reorientation dynamics of phototactic swimmers using 3D-tracking of free-swimming cells. Finally, we reconfirm, both theoretically and experimentally, that the adaptive nature of the response has peak fidelity at a frequency of about 1.6 Hz, corresponding to the rotation frequency of the cell body.

biophysics↗

bioRxiv2017

Phenotyping ciliary dynamics and coordination in response to CFTR-modulators in Cystic Fibrosis respiratory epithelial cells

The diagnosis and treatment of respiratory disorders are challenging and would benefit from new approaches to systematically assess ciliary beating dynamics and to test new drugs. A novel approach based on multiscale differential dynamic microscopy (multi-DDM) is shown to quantitatively assess collective beating of cilia in a non-biased automated manner, in human airway epithelial cells (HAECs) derived from subjects with cystic fibrosis (CF) and grown in 2D air-liquid interface culture. Multi-DDM can readily detect changes in both ciliary beat frequency (CBF) and cilia coordination that result from perturbations to the mucosal layer. The efficacy of three CFTR-modulating treatments is investigated: ivacaftor (VX-770) with lumacaftor (VX-809), VX-809 alone and Thymosin alpha 1 (T1) alone. All three treatments restore coordination of cilia beating in the CF cells, albeit to varying degrees. We argue cilia are affected by these treatments through the physical properties of the mucus. Phenotyping cilia dynamics through multi-DDM provides novel insight into the response of ciliary beating following treatment with drugs, and has application in the broader context of respiratory disease and for drug screening.\n\nOne sentence summaryA semi-automated and unbiased assay based on multiscale differential dynamic microscopy (multi-DDM) detects changes in the coordination and frequency of ciliary beating in F508del/F508del primary human airway cells under different conditions and in response to CFTR-modulating compounds.

physiology↗