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Biology subjects

Preece, D.

Publications and source records attributed to Preece, D..

3 recordsLinked to original sources

Investigation of astrocytes' morphological changes in response to laser-induced shockwave

Traumatic Brain Injury (TBI) arises from an external force affecting the brain, leading to a range of outcomes from mild to severe. Despite continuous scientific advancements, it continues to pose a persistent threat and remains a significant cause of physical impairment and mortality. Various models, including blast-induced TBI (bTBI), have been proposed to simulate TBI. Laser-induced shockwaves (LIS) us emerging as an effective method. LIS generates shockwaves via pulsed laser-induced plasma formation, offering a controlled means to study TBI at the cellular level. Astrocytes, pivotal in maintaining brain function post-injury, undergo dynamic morphological changes, contributing to the understanding of injury responses and neurodegenerative diseases. This study introduces a system combining Laser-Induced Shockwaves (LIS) and Quantitative Phase Microscopy (QPM) to quantify morphological changes in astrocytes during and after LIS exposure. QPM, a label-free method, facilitates 3D imaging and captures real-time cellular dynamics. The integration of LIS and QPM enables the assessment of astrocyte responses to shear stress caused by LIS, revealing immediate and sustained morphological transformations. Analysis post-LIS exposure indicates significant alterations in circularity, volume, surface area, and other features. Statistical tests affirm of observed trends, providing insights into astrocyte responses to mechanical forces. The findings contribute to understanding how mechanical stimuli impact astrocyte morphology, holding promise for targeted therapeutic strategies in traumatic brain injuries and related neurological disorders. The integrated LIS and QPM approach serves as a powerful tool for 3D imaging and quantitative measurement of astrocyte morphological changes, offering deeper insights into cellular dynamics and potential therapeutic interventions.

bioengineering↗

Mechanosensor Piezo1 Mediates Bimodal Patterns of Intracellular Signaling

Piezo1 belongs to mechano-activatable cation channels serving as biological force sensors. However, the molecular events downstream of Piezo1 activation remain unclear. In this study, we used biosensors based on fluorescence resonance energy transfer (FRET) to investigate the dynamic modes of Piezo1-mediated signaling and revealed a bimodal pattern of Piezo1-induced intracellular calcium signaling. Laser-induced shockwaves (LIS) and its associated shear stress can mechanically activate Piezo1 to induce transient intracellular calcium (Ca[i]) elevation, accompanied by an increase in FAK activity. Interestingly, multiple pulses of shockwave stimulation caused a more sustained calcium increase and a decrease of FAK activity. Similarly, tuning the degree of Piezo1 activation by titrating either the dosage of Piezo1 ligand Yoda1 or the expression level of Piezo1, produced a similar bimodal pattern of FAK responses. Specifically, a low degree of Piezo1 activation (transient mode) leads to a transient Ca[i] response with FAK activation, whereas a high degree of Piezo1 activation (sustained mode) causes a sustained Ca[i] response with FAK suppression. Further investigation revealed that SHP2 serves as an intermediate regulator mediating this bimodal pattern in Piezo1 sensing and signaling. These results suggest that the degrees of Piezo1 activation induced by both mechanical LIS and chemical ligand stimulation may determine downstream signaling characteristics.

biophysics↗

DNA damage induced during mitosis undergoes DNA repair synthesis

Understanding the mitotic DNA damage response (DDR) is critical to our comprehension of cancer, premature aging and developmental disorders which are marked by DNA repair deficiencies. In this study we use a micro-focused-laser to induce DNA damage in selected mitotic chromosomes to study the subsequent repair response. Our findings demonstrate that (1) mitotic cells are capable of DNA repair as evidenced by DNA synthesis at damage sites, (2) Repair is attenuated when DNA-PKcs and ATM are simultaneously compromised, (3) Laser damage may permit the observation of previously undetected DDR proteins when damage is elicited by other methods in mitosis, and (4) Twenty five percent of mitotic DNA-damaged cells undergo a subsequent mitosis. Together these findings suggest that mitotic DDR is more complex than previously thought and may involve factors from multiple repair pathways that are better understood in interphase.

cell biology↗