Description:

Peter Penzes, Ph.D., professor, and Colleen Zaccard, Ph.D., postdoc, will give a presentation.

Emerging advanced imaging methods are poised to uncover novel modalities whereby cells in the brain, both neurons and glia, communicate with each other. As part of a larger effort to understand noncanonical modalities of cellular connectivity, we have used live 3D enhanced-resolution microscopy to investigate the dynamics and function of understudied cellular projections, synaptic spinules on neurons, and tunneling nanotubes (TNTs) on microglia. We found that tiny spinules emerge and retract on dendritic spine heads, explore their environment, and often contact multiple distal presynaptic sites, thereby increasing the potential and actual connectivity of neurons. Spinules can have their own postsynaptic density, and are regulated by neuronal activity, calcium, small GTPase signaling and cytokines. We also found that microglia, the brain’s immune cells, project very long thin tubules, TNTs, which often contact neuronal dendritic spines and spinules. Cargo vesicles are often seen moving along TNTs. These findings show that brain cells communicate with each other through a wider range of modalities than previously thought, and open new avenues of research into their functions in health and disease.