Novel Approach to Image Mucin Release and Swelling

DESCRIPTION (provided by applicant): Mucus secretion is an important mechanism defending from irritants inhaled into the lungs during breathing. Secreted mucus forms a thin film of viscoelastic gel on the surface of the airways that protects the epithelial cells from irriants inhaled into the lungs by entrapping foreign debris, bacteria, and viruses and clearing them from the airway by ciliary movement; the whole process is termed mucociliary clearance. Besides its protective role, mucus could also have a pathologic roles in disease conditions, such as cystic fibrosis (CF), asthma, and chronic obstructive pulmonary disease (COPD), where excessive production of mucus (hypersecretion) and/or changes in its biophysical properties (viscoelasticity) result in the accumulation of thick, sticky mucus in the lungs, effectively impairing mucociliary clearance process. Since mucus is practically colorless viscous substance current video and light microscopy techniques used for studying mucus secretion suffer from poor resolution, sensitivity and limited temporal resolution. Fluorescence studies of mucin secretion are hampered by lack of well characterized fluorescent labels of mucin molecules and by difficulty to image in real-time a very rapid (~100 ms) secretion and swelling process. We recently tried a fluorescence approach with various fluorescence dyes to enable monitoring of mucin release on the cellular level and realized that the most interesting (important) processes occur in the initial steps when granules and generated mucus patches are small, frequently bellow optical resolution limits (