title: Use of optical tweezers technology for long-term, focal stimulation of specific subcellular neuronal compartments.
abstract: Spatial regulation of secretory molecule release is a sophisticated mechanism used by the nervous system to control network development and finely tune the activity of each synapse. Great efforts have been made to develop techniques that mimic secretory molecule release with the aim of stimulating neurons as close as possible to physiological conditions. However, current techniques have poor spatial resolution or low flexibility. Here, we propose a novel approach to achieve focal and prolonged stimulation of neurons using optical tweezers and single microbeads functionalized with a secretory molecule, the neurotrophin brain-derived neurotrophic factor (BDNF). BDNF is a key regulator of neuronal development and plasticity. We show that single BDNF-coated microbeads can be extracted with optical tweezers from small reservoirs and positioned with submicrometric precision to specific sites on the dendrites of cultured hippocampal neurons. Localized contact of microbeads functionalized with BDNF, but not with bovine serum albumin (BSA), induced focal increase of calcium signaling in the stimulated dendrite, specific activation of the TrkB receptor pathway and influenced the development of growth cones. Remarkably, a single BDNF-coated bead localized on a dendrite was found to be enough for TrkB phosphorylation, an efficient and long-lasting activation of calcium signaling in the soma, and c-Fos signaling in the nucleus, comparable to bath stimulation conditions. These findings support the use of optical tweezer technology for long-term, localized stimulation of specific subcellular neuronal compartments.
authors: Istituto Officina dei Materiali IOM-CNR, Laboratorio TASC, Area Science Park-Basovizza, S.S. 14 km 163.5, 34149 Trieste, Italy.
authors: Elisa
authors: E
authors: D'Este
authors: Gabriele
authors: G
authors: Baj
authors: Paolo
authors: P
authors: Beuzer
authors: Enrico
authors: E
authors: Ferrari
authors: Giulietta
authors: G
authors: Pinato
authors: Enrico
authors: E
authors: Tongiorgi
authors: Dan
authors: D
authors: Cojoc
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000008:administration & dosage*; D002460:Cell Line; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D052898:Optical Tweezers; D010812:Physical Stimulation / Q000379:methods*; D051381:Rats; D013347:Subcellular Fractions / Q000187:drug effects / Q000502:physiology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor