Biology subjects

Williantarra, I.

Publications and source records attributed to Williantarra, I..

4 recordsLinked to original sources

bioRxiv2026

Tissue osmotic surveillance shapes susceptibility of zebrafish to wound infections

Wounds represent compromised tissues that are susceptible to opportunistic infections. Tissue factors predisposing to wound infection include edema, poor vascularity, tissue hypoxia, necrosis, and wound size. However, it is unclear whether factors external to the tissue play a role. Detection of osmolarity imbalances between internal and external environment has been shown to alter epithelial wound closure and immune cell recruitment at injury sites. However, it remains unclear whether these osmotic surveillance pathways affect susceptibility to pathogenic wound infections. Here, we use live imaging and disease monitoring in zebrafish larvae to understand susceptibility of wound infection towards Pseudomonas aeruginosa. We show that exposure of wounds to isotonic solution results in enhanced susceptibility and pathogen burden. Furthermore, we demonstrate that this higher propensity for infection depends on osmolarity-mediated changes in wound sealing and neutrophil recruitment during the early stages of the wound response. These findings inform the design of experimental wound infection models as well as the clinical management of wounds.

cell biology↗

bioRxiv2025

In form for a swarm: programmable neutrophil swarming impacts infection outcome

Many migrating cells pattern signalling molecules to support their accumulation in target tissues. During inflammation, neutrophils achieve rapid swarming at sites of injury or infection by generating spatiotemporal gradients of chemoattractants. Whether these self-generated behaviours can be re-programmed to change disease course is unclear. Here, we show that neutrophil chemoattractant patterning machinery is subject to transcriptional reprogramming after microbial experience, leading to enhanced swarming and control of infection at subsequent wound sites in zebrafish. Through in vitro assays, we demonstrate that "trained swarming phenotypes" are cell-intrinsic and independent of the nature of the microbial target. Furthermore, genetic enhancement of 5-lipoxygenase in neutrophils is sufficient to improve neutrophil swarming and resistance to wound infection. Through mathematical modelling, we demonstrate that neutrophil-intrinsic alterations in chemoattractant release are sufficient to recapitulate trained swarming in infection-experienced animals. Together, these data suggest new routes for reprogramming cell migration in disease settings, via manipulating their ability to shape chemoattractant landscapes.

immunology↗

bioRxiv2025

Chemotaxis of branched cells in complex environments

Cell migration in vivo is often guided by chemical signals. Such chemotaxis, such as performed by immune cells migrating to a wound site, is complicated by the complex geometry inside living tissues. In this study, we extend our theoretical model of branched-cell migration on a network by introducing chemokine sources to explore the cellular response. The model predicts a speed-accuracy tradeoff, whereby slow cells are significantly more accurate and able to follow efficiently a weak chemoattractant signal. We then compare the models predictions with experimental observations of neutrophils migrating to the site of laser-inflicted wound in a zebrafish larva fin, and migrating in-vitro inside a regular lattice of pillars. We find that the model captures the details of the sub-cellular response to the chemokine gradient, as well as the large-scale migration response. This comparison suggests that the neutrophils behave as fast cells, compromising their chemotaxis accuracy, which explains the functionality of these immune cells.

biophysics↗

bioRxiv2021

Matrix stiffness controls ciliogenesis and centriole position

Mechanical stress and the stiffness of the extracellular matrix are key drivers of tissue development and homeostasis. Aberrant mechanosensation is associated with a wide range of pathologies, including diseases such as osteoarthritis. Substrate stiffness is one of the well-known mechanical properties of the matrix that enabled establishing the central dogma of an integrin-mediated mechanotransduction using stem cells. However, how specific cells feel or sense substrate stiffness requires further study. The primary cilium is an essential cellular organelle that senses and integrates mechanical and chemical signals from the extracellular environment. We hypothesised that the primary cilium dynamically alters its length and position to fine-tune cell mechanosignalling based on substrate stiffness alone. We used a hydrogel system of varying substrate stiffness to examine the role of substrate stiffness on cilia frequency, length and centriole position as well as cell and nuclei area over time. Contrary to other cell types, we show that chondrocyte primary cilia shorten on softer substrates demonstrating tissue-specific mechanosensing which is aligned with the tissue stiffness the cells originate from. We further show that stiffness alone determines centriole positioning to either the basal or apical membrane during attachment and spreading, with centriole positioned towards the basal membrane on stiffer substrates. These phenomena are mediated by force generation actin-myosin stress fibres in a time-dependent manner. Based on these findings, we propose that substrate stiffness plays a central role in cilia positioning, regulating cellular response to external forces, and may be a key driver of mechanosignalling-associated diseases. Significance StatementThe primary cilium has been thrust into the limelight owing to its role as a cellular sensor in embryonic development and adult tissue maintenance. How the primary cilium interacts with the mechanical environment still remains unclear. We show that substrate stiffness dynamically regulates primary cilium length and position through integrin-mediated traction forces, the cilia are a key determinant of cell shape on certain stiffnesses. Our data support the promising potential of primary cilia as a novel target in mechanotherapy for improved clinical outcomes in cartilage pathobiology.

cell biology↗