Roles of gap junctions in excitable and inexcitable cells
Research of our laboratory is centered on physiological and cell/molecular biological studies of gap junctions, the intercellular channels that allow cells to directly exchange ions and metabolites. In the nervous system, gap junctions form electrotonic synapses between neurons, permitting synchronized excitation of coupled cells, and they couple glia into a complex interconnected network where information is exchanged through calcium waves and metabolically. Major projects of the laboratory are attempting to resolve (1) role of gap junctions and extracellular signaling in a mouse model of orofacial pain, (2) how connexin-protein interactions (which result in a dynamic complex that we term the “Nexus”) deliver, assemble and modulate gap junctions in various cell types, (3) the role of gap junctions in stem cell therapy in a mouse model of Chagas disease (with H.B. Tanowitz, Dept Pathology), (4) endothelial cell and astrocyte mechanotransduction and cell polarization in a blood-brain-barrier model (with members of the Biomedical Engineering Department, CCNY). These studies utilize a variety of preparations, including primary cultures of cells from transgenic mice with altered expression of connexin and other genes and transfection of wildtype and mutated connexin sequences into communication deficient cell lines, where small high resistance cells permit structure-function analysis at the single channel level. Techniques include intracellular recordings with conventional and ion-selective microelectrodes, photomanipulation such as FRAP, optical monitoring of intracellular ionic activities (especially Ca2+ and propagated Ca2+ waves), patch clamp recording of single channels and whole cell currents and standard molecular biological and immunological methods such as Northern and Western blot analyses, immunostaining and RT-PCR and expression profiling using microarrays.