Transformation of SH-SY5Y cell line into neuron-like cells: Investigation of electrophysiological and biomechanical changes.

SH-SY5Y human neuroblastoma cells are commonly used as neuronal models. Here, we examined different aspects of SH-SY5Y cell differentiation. Various differentiation protocols have been proposed previously, including treatments with retinoic acid, brain-derived neurotrophic factor (BDNF), cholesterol and oestradiol. We examined undifferentiated SH-SY5Y cells (UNDIFF); cells differentiated by the treatment with retinoic acid (RA); retinoic acid + BDNF (RB); and retinoic acid + BDNF + cholesterol + oestradiol (RBCE). We performed whole-cell patch-clamp recordings from these cells and nanomechanically characterised them by using atomic force microscopy (AFM). Our results indicated that Na+ currents become most pronounced in the differentiated RB cells, whereas UNDIFF SH-SY5Y cells had significantly larger K+ currents, which is a characteristic feature of cancer cells. AFM observations of these two groups showed that Young's moduli of SH-SY5Y cells increased threefold with differentiation. Furthermore, we showed a direct relationship between Na+ channel activity and elasticity in these cells. We conclude that SH-SY5Y human neuroblastoma cells should be used as a neuronal model only when they are differentiated by the treatment with retinoic acid and BDNF.

A Transient Survival Model of Alteration of Electrophysiological Properties Due to Amyloid Beta Toxicity Based on SH-SY5Y Cell Line.

BACKGROUND: Accumulation of toxic strands of amyloid beta (AB), which cause neurofibrillary tangles and, ultimately, cell death, is suspected to be the main culprit behind clinical symptoms of Alzheimer's disease. Although the mechanism of cell death due to AB accumulation is well known, the intermediate phase between the start of accumulation and cell death is less known and investigated, partially due to technical challenges in identifying partially affected cells. OBJECTIVE: First, we aimed to establish an in vitro model that would show resilience against AB toxicity. Then we used morphological, molecular and electrophysiological assays to investigate how the characteristics of the surviving cells changed after AB toxicity. METHODS: To investigate this phase, we used differentiation of SH-SY5Y neuroblastoma stem cells by Retinoic Acid (RA) and Brain Derived Neurotrophic Factor (BDNF) to establish an in vitro model which would be able to demonstrate various levels of resistance to AB toxicity. We utilized fluorescent microscopy and whole cell patch clamp recordings to investigate behavior of the model. RESULTS: We observed significantly higher morphological resilience against AB toxicity in cells which were differentiated by both Retinoic Acid and Brain Derived Neurotrophic Factor compared to Retinoic Acid only. However, the electrophysiological properties of the Retinoic Acid + Brain-Derived Neurotrophic Factor differentiated cells were significantly altered after AB treatment. CONCLUSION: We established a transient survival model for AB toxicity and observed the effects of AB on transmembrane currents of differentiated neurons.