In vitro model of synaptic activity for the investigation of molecular mechanisms of synaptic plasticity and neuroprotection

Neurons communicate by means of synaptic activity, a process that affects brain development, neuronal health, and the ability to strengthen the connections between neurons and thus to regulate high order functions including learning and memory. Synaptic activity acts through the involvement of a fine regulated expression of several genes (activity-regulated genes) in different waves of induction: a rapid activation of immediate- early genes and then the expression of late effector genes. A growing amount of genome-wide expression data is showing that some of those genes are associated with neurological diseases and have specifically evolved in primates or humans. This feature constraints the right choice of the experimental model to be used not only for a 201 descriptive analysis but also for functional studies to uncover the specific role of that genes. In this regard, among in vitro human models, the SH-SY5Y is a popular cell line largely used in neurobiology and represents a cost-effective and user-friendly platform for several molecular investigation. We developed a synaptic activity model on differentiated SH-SY5Y cells by using high potassium solution to induce depolarization. The differentiation protocol was based on combined used of retinoic acid and BDNF for 12 days. Depolarization process was monitored by fluorescent analysis of synaptic vesicles release and recycle, and induction of immediate- early genes. The effectiveness of the model was also confirmed analyzing the expression of several coding and non-coding genes after 8 hours of depolarization, including genes involved in neuroprotection.