Enhancement of FAK alleviates ventilator-induced alveolar epithelial cell injury

Stress stimulation promotes the injury repair process of airway epithelial cells through the [Cl-]i-FAK signaling axis

The airway epithelium serves as a critical interface with the external environment, making it vulnerable to various external stimuli. Airway epithelial stress acts as a catalyst for the onset of numerous pulmonary and systemic diseases. Our previous studies have highlighted the impact of acute stress stimuli, especially bacterial lipopolysaccharide (LPS) and hydrogen peroxide (H2O2), on the continuous elevation of intracellular chloride concentration ([Cl-]i). However, the precise mechanism behind this [Cl-]i elevation and the consequential effects of such stress on the injury repair function of airway epithelial cells remain unclear. Our findings indicate that H2O2 induces an elevation in [Cl-]i by modulating the expression of CF transmembrane conductance regulator (CFTR) and Ca-activated transmembrane protein 16 A (TMEM16A) in airway epithelial cells (BEAS-2B), whereas LPS achieves this solely through CFTR. Subsequently, the elevated [Cl-]i level facilitated the injury repair process of airway epithelial cells by activating focal adhesion kinase (FAK). In summary, the [Cl-]i-FAK axis appears to play a promoting effect on the injury repair process triggered by stress stimulation. Furthermore, our findings suggest that abnormalities in the [Cl-]i-FAK signaling axis may play a crucial role in the pathogenesis of chronic airway diseases. Therefore, controlling the structure and function of airway epithelial barriers through the modulation of [Cl-]i holds promising prospects for future applications in managing and treating such conditions.

Random and aligned electrostatically spun PLLA nanofibrous membranes enhance bone repair in mouse femur midshaft defects

Long-segment bone defects are a common clinical challenge and abstract biomaterials are a promising therapy. Poly-L-lactic acid (PLLA) nanofibrous membranes prepared by electrostatic spinning have a good bone repair potential. However, there are random and aligned surface morphologies of electrostatic spun PLLA nanofibrous membranes, which can affect the migration, proliferation, and differentiation ability of cells. The role of surface morphology in the repair of long bone defects in vivo is currently unknown. In this study, random and aligned electrostatically spun PLLA nanofibrous membranes were prepared, characterised, and implanted into a femur midshaft defect mouse model. The ability of electrostatically spun PLLA nanofibrous membranes to enhance bone repair was tested using X-ray photography, high-resolution micro-computed tomography (micro-CT), and pathological section specimens. The results showed that both random and aligned electrostatically spun PLLA nanofibrous membranes enhanced bone regeneration at bone defects, but the aligned ones exhibited superior results. These results provide a theoretical basis for engineering the surface morphology of bone repair materials.

Ventilator-induced lung-injury in mouse models: Is there a trap?

Ventilator-induced lung injury (VILI) is a serious acute injury to the lung tissue that can develop during mechanical ventilation of patients. Due to the mechanical strain of ventilation, damage can occur in the bronchiolar and alveolar epithelium resulting in a cascade of events that may be fatal to the patients. Patients requiring mechanical ventilation are often critically ill, which limits the possibility of obtaining patient samples, making VILI research challenging. In vitro models are very important for VILI research, but the complexity of the cellular interactions in multi-organ animals, necessitates in vivo studies where the mouse model is a common choice. However, the settings and duration of ventilation used to create VILI in mice vary greatly, causing uncertainty in interpretation and comparison of results. This review examines approaches to induce VILI in mouse models for the last 10 years, to our best knowledge, summarizing methods and key parameters presented across the studies. The results imply that a more standardized approach is warranted.