A novel tubular model to recapitulate features of distal airways: the bronchioid.

Background: Airflow limitation is the hallmark of obstructive pulmonary diseases, with the distal airways representing a major site of obstruction. Although numerous models of bronchi already exist, there is currently no culture system for obstructive diseases that reproduces the architecture and function of small airways. Here, we aimed to engineer a model of distal airways to overcome the limitations of current culture systems.

Two-photon Dye-Based Fluorogenic Organic Nanoparticles as Intracellular Thiols Sensors.

Optical bioimaging is an ever-growing field that benefits both from the fast progress of optical instrumentation and modalities, and from the development of light-emitting probes. The efficacy of molecular fluorescent dyes is crucial, yet hindered by limited brightness and hydrophilicity. Addressing these challenges, self-stabilized fluorogenic organic nanoparticles only made of pure dyes (dFONs) are introduced in this work.

is a multifunctional factor priming human embryonic genome activation.

Double homeobox 4 () is expressed at the early pre-implantation stage in human embryos. Here we show that induced human expression substantially alters the chromatin accessibility of non-coding DNA and activates thousands of newly identified transcribed enhancer-like regions, preferentially located within ERVL-MaLR repeat elements. CRISPR activation of transcribed enhancers by C-terminal DUX4 motifs results in the increased expression of target embryonic genome activation (EGA) genes and .

[3D Tumor organoid models produced by cellular capsules technology CCT].

Monolayer cultures of cell lines and derived-patient cells have long been the in vitro model of choice in oncology. In particular, these models have made it possible to decipher the mechanisms that determine tumor proliferation and invasion. However these 2D models are insufficient because they do not take into account the spatial organization of cells and their interactions with each other or with the extracellular matrix.

Remote scanning for ultra-large field of view in wide-field microscopy and full-field OCT.

Imaging specimens over large scales and with a sub-micron resolution is instrumental to biomedical research. Yet, the number of pixels to form such an image usually exceeds the number of pixels provided by conventional cameras. Although most microscopes are equipped with a motorized stage to displace the specimen and acquire the image tile-by-tile, we propose an alternative strategy that does not require to move any part in the sample plane.

Confinement of Dyes inside Boron Nitride Nanotubes: Photostable and Shifted Fluorescence down to the Near Infrared.

Fluorescence is ubiquitous in life science and used in many fields of research ranging from ecology to medicine. Among the most common fluorogenic compounds, dyes are being exploited in bioimaging for their outstanding optical properties from UV down to the near IR (NIR). However, dye molecules are often toxic to living organisms and photodegradable, which limits the time window for in vivo experiments.

A 3D Spheroid Model for Glioblastoma.

Two-dimensional (2D) cell cultures do not mimic in vivo tumor growth satisfactorily. Therefore, three-dimensional (3D) culture spheroid models were developed. These models may be particularly important in the field of neuro-oncology.

Complement in Human Pre-implantation Embryos: Attack and Defense.

It is essential for early human life that mucosal immunological responses to developing embryos are tightly regulated. An imbalance of the complement system is a common feature of pregnancy complications. We hereby present the first full analysis of the expression and deposition of complement molecules in human pre-implantation embryos.

Lens apoptosis in the Astyanax blind cavefish is not triggered by its small size or defects in morphogenesis.

Blindness is a convergent trait in many cave animals of various phyla. Astyanax mexicanus cavefish is one of the best studied cave animals; however the mechanisms underlying eye degeneration in this species are not yet completely understood. The lens seems to play a central role, but only relatively late differentiation defects have been implicated in the cavefish lens apoptosis phenotype so far.

All-in-one 3D printed microscopy chamber for multidimensional imaging, the UniverSlide.

While live 3D high resolution microscopy techniques are developing rapidly, their use for biological applications is partially hampered by practical difficulties such as the lack of a versatile sample chamber. Here, we propose the design of a multi-usage observation chamber adapted for live 3D bio-imaging. We show the usefulness and practicality of this chamber, which we named the UniverSlide, for live imaging of two case examples, namely multicellular systems encapsulated in sub-millimeter hydrogel shells and zebrafish larvae.

A Conserved Developmental Mechanism Builds Complex Visual Systems in Insects and Vertebrates.

The visual systems of vertebrates and many other bilaterian clades consist of complex neural structures guiding a wide spectrum of behaviors. Homologies at the level of cell types and even discrete neural circuits have been proposed, but many questions of how the architecture of visual neuropils evolved among different phyla remain open. In this review we argue that the profound conservation of genetic and developmental steps generating the eye and its target neuropils in fish and fruit flies supports a homology between some core elements of bilaterian visual circuitries.

Self-organization of the human embryo in the absence of maternal tissues.

Remodelling of the human embryo at implantation is indispensable for successful pregnancy. Yet it has remained mysterious because of the experimental hurdles that beset the study of this developmental phase. Here, we establish an in vitro system to culture human embryos through implantation stages in the absence of maternal tissues and reveal the key events of early human morphogenesis.

A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage.

The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data.

Structural origin of the drastic modification of second harmonic generation intensity pattern occurring in tail muscles of climax stages xenopus tadpoles.

Second harmonic generation (SHG) microscopy is a powerful tool for studying submicron architecture of muscles tissues. Using this technique, we show that the canonical single frequency sarcomeric SHG intensity pattern (SHG-IP) of premetamorphic xenopus tadpole tail muscles is converted to double frequency (2f) sarcomeric SHG-IP in metamorphic climax stages due to massive physiological muscle proteolysis. This conversion was found to rise from 7% in premetamorphic muscles to about 97% in fragmented muscular apoptotic bodies.

Zebrafish midbrain slow-amplifying progenitors exhibit high levels of transcripts for nucleotide and ribosome biogenesis.

Investigating neural stem cell (NSC) behaviour in vivo, which is a major area of research, requires NSC models to be developed. We carried out a multilevel characterisation of the zebrafish embryo peripheral midbrain layer (PML) and identified a unique vertebrate progenitor population. Located dorsally in the transparent embryo midbrain, these large slow-amplifying progenitors (SAPs) are accessible for long-term in vivo imaging.

Study of the effect of myofibrillar misalignment on the sarcomeric SHG intensity pattern.

We present a theoretical simulation of the sarcomeric SHG intensity pattern (SHG-IP) that takes into account myofibrillar misalignment that is experimentally observed in SHG images of proteolysed muscles. The model predicts that myofibrillar displacement results in the conversion from one peak (1P) to two peaks (2P) sarcomeric SHG-IP in agreement with experimental results. This study suggests that sarcomeric SHG-IP is a powerful tool for mapping spatial myofibrillar displacement and its related excitation-contraction disruption that could occur during muscle physiological adaptation and disease.

Theoretical and experimental SHG angular intensity patterns from healthy and proteolysed muscles.

SHG angular intensity pattern (SHG-AIP) of healthy and proteolysed muscle tissues are simulated and imaged here for the first time to our knowledge. The role of the spatial distribution of second-order nonlinear emitters on SHG-AIP is highlighted. SHG-AIP with two symmetrical spots is found to be a signature of healthy muscle whereas SHG-AIP with one centered spot in pathological mdx muscle is found to be a signature of myofibrillar disorder.

Dipolar versus octupolar triphenylamine-based fluorescent organic nanoparticles as brilliant one- and two-photon emitters for (bio)imaging.

Two related triphenylamine-based dipolar and octupolar fluorophores are used to prepare aqueous suspensions of fluorescent organic nanoparticles (FONs) via the reprecipitation method. The obtained spherical nanoparticles (30-40 nm in diameter) are fluorescent in aqueous solution (up to 15% fluorescence quantum yield) and exhibit extremely high one- and two-photon brightness, superior to those obtained for quantum dots. Despite the two chromophores showing similar fluorescence in solution, the fluorescence of FONs made from the octupolar derivative is significantly red-shifted compared to that generated by the dipolar FONs.

Modeling of supramolecular centrosymmetry effect on sarcomeric SHG intensity pattern of skeletal muscles.

A theoretical far-field second harmonic generation (SHG) imaging radiation pattern is calculated for muscular myosin taking into account both Gouy effect and light diffraction under high focusing excitation. Theoretical analysis, in agreement with experimental results obtained on healthy Xenopus muscles, shows that the increase on intensity at the middle of the sarcomeric SHG intensity pattern is generated by an off-axis constructive interference related to the specific antipolar distribution of myosin molecules within the sarcomere. The best fit of the experimental sarcomeric SHG intensity pattern was obtained with an estimated size of antiparallel, intrathick filaments' packing-width of 115 ± 25 nm localized at the M-band.

Skeletal muscle sarcomeric SHG patterns photo-conversion by femtosecond infrared laser.

Femtosecond laser at 780 nm excitation wavelength was used to photo-convert the physiological sarcomeric single band (SB) second harmonic generation (SHG) pattern into double band (DB) in Xenopus laevis premetamorphic tail muscles. This photo-conversion was found to be a third order non-linear optical process and was drastically reduced at 940 nm excitation wavelength. This effect was no longer observed in paraformaldehyde fixed muscles and was enhanced by hydrogen peroxide.

Three distinct sarcomeric patterns of skeletal muscle revealed by SHG and TPEF microscopy.

We have extensively characterized the sarcomeric SHG signal as a function of animal species (rat versus xenopus), age (adult versus larval) and tissue preparation (fixed or fresh) and we found that the main feature of this signal is a single peak per mature sarcomere (about 85% of all sarcomeres). The remaining (15%) was found to be either double peak per mature sarcomere or mini sarcomeres (half of a sarcomere) using alpha-actinin immuno detection of the Z-band. The mini sarcomeres are often found in region of pitchfork-like SHG pattern.