Biology subjects

Bernardello, M.

Publications and source records attributed to Bernardello, M..

2 recordsLinked to original sources

bioRxiv2023

Dynamics of macrophage polarization support Salmonella persistence in a whole living organism

Numerous intracellular bacterial pathogens interfere with macrophage function, including macrophage polarization, to establish a niche and persist. However, the spatiotemporal dynamics of macrophage polarization during infection within host remain to be investigated. Here, we implement a model of persistent Salmonella Typhimurium infection in zebrafish, which allows visualization of polarized macrophages and bacteria in real time at high-resolution. While macrophages polarize toward M1-like phenotype to control early infection, during later stages, Salmonella persists inside non-inflammatory clustered macrophages. Transcriptomic profiling of macrophages confirmed a highly dynamic signature during infection characterized by a switch from pro-inflammatory to anti-inflammatory/pro-regenerative status and revealed a shift in adhesion program. In agreement with this specific adhesion signature, macrophage trajectory tracking identifies motionless macrophages as a permissive niche for persistent Salmonella. Our results demonstrate that zebrafish model provides a unique platform to explore, in a whole organism, the versatile nature of macrophage functional programs during bacterial acute and persistent infections.

immunology↗

bioRxiv2020

The microtubule organization in the zebrafish yolk adapts to transgene-mediated phenotypic variations

The organization of microtubule networks in the cells is orchestrated by subcellular structures named microtubule organizing centers (MTOCs). In zebrafish embryos, the yolk is surrounded by a cytoplasmic layer containing a vast network of microtubules. In order to understand how this complex network is organized, we use dclk2-GFP zebrafish embryos, as a microtubule reporter line, and Light Sheet Fluorescence Microscopy. We find that this organization is mediated by a variable number of aster-like MTOCs during epiboly, and that it does not follow a rigid scheme, exemplifying developmental robustness. We characterize asters morphology, dynamics, and their uniform distribution in the yolk sphere. Consistent with their role as MTOCs we find that they contain key molecular machinery for MTs dynamics, amongst which centrin marks the assignation of MTOCs over time. Finally, we demonstrate that merely the overexpression of dclk2-GFP in wild type embryos can induce the formation of asters. We propose dclk2-GFP embryos as a model for the study of the collective behaviour of microtubules in complex systems.

developmental biology↗