Biology subjects

Ingham, P. W.

Publications and source records attributed to Ingham, P. W..

3 recordsLinked to original sources

bioRxiv2024

Genetic regulation of injury induced heterotopic ossification in adult zebrafish

Heterotopic ossification is the inappropriate formation of bone in soft tissues of the body. It can manifest spontaneously in rare genetic conditions or as a response to injury, known as acquired heterotopic ossification. There are several experimental models for studying heterotopic ossification from different sources of damage. However, their tenuous mechanistic relevance to the human condition, invasive and laborious nature and/or lack of amenability to chemical and genetic screens, limit their utility. To address these limitations, we developed a simple zebrafish injury model that manifests heterotopic ossification in response to micro-fractures in combination with muscle injury. These findings indicate that clinically-emulated injuries in zebrafish can lead to osteo-induction and proliferation as observed in heterotopic ossification in myositis ossificans traumatica. Exploiting this model, we analysed the penetrance and expressivity of heterotopic ossification and defined the transcriptional response to trauma, identifying differentially regulated genes. Taking advantage of defined mutants in several of these candidates, we explored their impact on heterotopic bone formation. Our findings revealed that an increase in potassium channel Kcnk5b activity potentiates injury response. In contrast, we demonstrate that inflammatory responses are essential for the ectopic bone growth, as mutations in Interleukin 11 receptor paralogue (Il11ra) exhibit a drastically reduced ossification response. Based on these findings, we postulate that enhanced ionic signaling, specifically through Kcnk5b, regulates the intensity of the skeletogenic injury response, which, in part, requires immune response regulated by Il11ra.

genetics↗

bioRxiv2020

Blood vessel occlusion by Cryptococcus neoformans is a mechanism for hemorrhagic dissemination of infection

Meningitis caused by infectious pathogens are associated with vessel damage and infarct formation, however the physiological cause is unknown. Cryptococcus neoformans, is a human fungal pathogen and causative agent of cryptococcal meningitis, where vascular events are observed in up to 30% of cases, predominantly in severe infection. Therefore, we aimed to investigate how infection may lead to vessel damage and associated pathogen dissemination using a zebrafish model for in vivo live imaging. We find that cryptococcal cells become trapped within the vasculature (dependent on there size) and proliferate there resulting in vasodilation. Localised cryptococcal growth, originating from a single or small number of cryptococcal cells in the vasculature was associated with sites of dissemination and simultaneously with loss of blood vessel integrity. Using a cell-cell junction tension reporter we identified dissemination from intact blood vessels and where vessel rupture occurred. Finally, we manipulated blood vessel stifness via cell junctions and found increased stiffness resulted in increased dissemination. Therefore, global vascular vasodilation occurs following infection, resulting in increased vessel tension which subsequently increases dissemination events, representing a positive feedback loop. Thus, we identify a mechanism for blood vessel damage during cryptococcal infection that may represent a cause of vascular damage and cortical infarction more generally in infective meningitis.

pathology↗

bioRxiv2019

Neutrophils use selective autophagy receptor p62 to target Staphylococcus aureus for degradation in the zebrafish model

Autophagy leads to degradation of cellular components and has an important role in restricting intracellular pathogens. Autophagy receptors, including p62, target invading intracellular pathogens to the autophagy pathway for degradation. Staphylococcus aureus is a significant pathogen of humans and often life-threatening in the immunocompromised. Increasing evidence demonstrates that S. aureus is an intracellular pathogen of immune cells and may use neutrophils as proliferative niche but the intracellular fate of S. aureus following phagocytosis by neutrophils has not previously been analysed in vivo. In vitro, p62 is able to co-localise with intracellular Staphylococcus aureus, but whether p62 is beneficial or detrimental in host defence against S. aureus in vivo had not been determined. Here we use zebrafish to determine the fate and location of S. aureus within neutrophils throughout infection. We show that Lc3 and p62 recruitment to phagocytosed S. aureus is altered depending on the bacterial location within the neutrophil. We also show rapid Lc3 marking of bacterial phagosomes within neutrophils which may be associated with subsequent bacterial degradation. Finally, we find that p62 is important for controlling cytosolic bacteria demonstrating for the first time a key role of p62 in autophagic control of S. aureus in neutrophils.

immunology↗