Biology subjects

Kriselj, A.

Publications and source records attributed to Kriselj, A..

3 recordsLinked to original sources

bioRxiv2024

Novel correlative microscopy approach for nano-bio interface studies of ultrafine particle-induced lung epithelial cell damage

Correlated light and electron microscopy (CLEM) has become essential in life sciences due to advancements in imaging resolution, sensitivity, and sample preservation. In nanotoxicology-- specifically, studying the health effects of particulate matter exposure--CLEM can enable molecular-level structural as well as functional analysis of nanoparticle interactions with lung tissue, key for the understanding of modes of action. In our study, we for the first time implement an integrated high-resolution fluorescence lifetime imaging microscopy (FLIM) and hyperspectral fluorescence imaging (fHSI), scanning electron microscopy (SEM), ultra-high resolution helium ion microscopy (HIM) and synchrotron micro X-ray fluorescence (SR {micro}XRF), to characterize the nano-bio interface and to better elucidate the modes of action of lung epithelial cells response to known inflammatory titanium dioxide nanotubes (TiO2 NTs). Morpho-functional assessment uncovered several mechanisms associated with the extensive DNA, essential minerals and iron accumulation, cellular surface immobilization, and the localized formation of fibrous structures, all confirming immunomodulatory responses. These findings advance our understanding of the early cellular processes leading to inflammation development after lung epithelium exposure to these, high-aspect-ratio nanoparticles. The novel experimental approach, exploiting light, ion and electron sources, provides a robust framework for future research into nanoparticle toxicity and its impact on human health.

cell biology↗

bioRxiv2020

Towards predictive nanotoxicology: from roundabout of molecular events to chronic inflammation prediction

Nanomaterial-induced diseases cannot be reliably predicted because of the lack of clearly identified causal relationships, in particular between acute exposures and chronic symptoms. By applying advanced microscopies and omics to in vitro and in vivo systems, together with in silico molecular modelling, we have here determined that the long-lasting response to a single exposure originates in the counteracting of a newly discovered nanomaterial quarantining and nanomaterial cycling among different lung cell types. This allows us to predict the nanomaterial-induced spectrum of lung inflammation using only in vitro measurements and in silico modelling. Besides its profound implications for cost-efficient animal-free predictive toxicology, our work also paves the way to a better mechanistic understanding of nanomaterial- induced cancer, fibrosis, and other chronic diseases.

molecular biology↗

bioRxiv2019

Random birth order and bursty Notch ligand expression drive the stochastic AC/VU cell fate decision in C. elegans

Cells in developing organisms must robustly assume the correct fate in order to fulfill their specific function. At the same time, cells are strongly affected by molecular fluctuations, i.e. noise, leading to inherent variability in individual cells. During development, some cells are thought to exploit such molecular noise to drive stochastic cell fate decisions, with cells randomly picking one cell fate out of several possible ones. Yet, how molecular noise drives such decisions is an open question. We address this question using a novel quantitative approach to study one of the best-understood stochastic cell fate decisions: the AC/VU decision in C. elegans gonad development. Here, two initially equivalent cells, Z1.ppp and Z4.aaa, interact, so that one cell becomes the anchor cell (AC) and the other a ventral uterine precursor cell (VU). It is thought that the symmetry is broken when small molecular fluctuations are amplified into cell fate by positive feedback loops in the Notch signaling pathway. To identify the noise sources that drive the AC/VU decision, we used a novel time-lapse microscopy approach to follow expression dynamics in live animals and single molecule FISH to quantify gene expression with single mRNA resolution. We found not only that random Z1.ppp/Z4.aaa birth order biased the decision outcome, with the first-born cell typically assuming VU fate, but that the strength of this bias and the speed of the decision decreased as the two cells were born closer together in time. Moreover, we find that the Notch ligand lag-2/Delta exhibited strongly stochastic expression already in the two mother cells, Z1.pp/Z4.aa. Combining experiments with mathematical models, we showed that the resulting asymmetry in lag-2/Delta levels inherited by the daughter cells, Z1.ppp/Z4.aaa, stochastic symmetry breaking when both cells are born at similar times. Together, our results suggest that two independent noise sources, birth order and stochastic lag-2/Delta expression, are exploited to amplify noise into cell fate in a manner that ensures a robust decision.

developmental biology↗