# Systematic Analysis of SH-SY5Y Differentiation Protocols and Neuronal Subtype Abundance

## TL;DR

This paper compares different methods to differentiate SH-SY5Y cells into specific neuronal subtypes and finds that low serum and retinoic acid promote dopaminergic neurons.

## Contribution

The study systematically evaluates and compares four differentiation protocols for SH-SY5Y cells to determine their effects on neuronal subtype abundance.

## Key findings

- Low serum concentration promotes mature neuronal cells with long neurites.
- Retinoic acid with low serum increases dopaminergic marker protein DDC.
- Proteomic analysis reveals protocol-specific effects on neuronal differentiation.

## Abstract

The SH-SY5Y cell line is a triple-cloned subline of SK-N-SH cells originally isolated in the early 1970s from a bone marrow biopsy of a four-year-old female patient suffering from neuroblastoma. Since then, this cell line has been used as one of the major cell culture models in neuroscience and to study neurodegeneration, as it comprises many of the biochemical and functional properties of neural precursor cells. Differentiation of neuronal precursor cells into a more mature phenotype represents one of the key steps and directed differentiation utilising various reagents is thought to provoke a defined neuronal subtype. Unfortunately, until now there is no consensus, which protocol shall be utilised to reach a specific neuronal subtype. Thus, the aim of the present work was to evaluate four common standard protocols for the differentiation of SH-SY5Y cells and to investigate the respective influences of varying parameters of these differentiation strategies. For this purpose, morphological analyses, mass spectrometry-based quantification of specific marker proteins, time-course protein expression profiling and global proteomics were conducted. On the level of morphology a low serum concentration favoured the abundance of mature neuronal cells containing long and branched neurites. Further low serum levels favoured the expression of dopaminergic marker proteins, in particular DDC, especially when utilising retinoic acid as differentiation agent. Our study clearly shows that an a priori characterisation of SH-SY5Y cells is indispensable to assess the abundance of neuronal subtypes and by that to ensure that the utilised differentiation approach is appropriately aligned with the specific research question.

The online version contains supplementary material available at 10.1007/s10571-025-01627-0.