Conversion of Human Fibroblasts into Neuronal Cells by Small Molecules

Biologists in Shanghai, China, have achieved direct conversion of normal and familial Alzheimer's Disease (FAD) human fibroblasts into functional neuronal cells through use of small molecules. In their published report, they aim to prove the resulting human chemical-induced neuronal cells (hciNs) are similar to human induced pluripotent stem cell (hiPSC)-derived neurons and other human induced neurons in morphology, gene expression profiles, and electrophysiological properties. In a previous paper, the biologists applied a chemical cocktail to convert mouse fibroblasts and human urinary cells into neural progenitor cells. Thus for their current report, successfully converting fibroblasts sourced from FAD patients illustrates their steps towards potential treatments in regenerative medicine and providing novel strategies for modeling neurological disease.

After completing the induction of their neuronal cells, the next objective was to verify that the hciNs were able to function properly. Since patch-clamp analysis could only process a small amount of cells, the researchers decided to use calcium indicator Cal-520 to observe the activity of large numbers of hciNs at once. The researchers observed very robust and spontaneous calcium responses, suggesting that the hciN neural network was active. They compared the percentage of active hciNs with a culture of iPSC-derived neurons under the same Cal-520 treatment and concluded that they were not significantly different from one another.

Cal-520 is often used as a sensitive fluorescent probe for visualizing neural activity, due to its affinity and fluorogenic response with and to calcium. Cal-520 is also relatively easy to use and apply to larger amounts of cells, including thicker bolus loading. Therefore, Cal-520 is a most fitting dye for this study and other similar neuroscience experiments.

References

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1. Wenxiang Hu, Binlong Qiu, Wuqiang Guan, Qinying Wang, Min Wang, Wei Li, Longfei Gao, Lu Shen,Yin Huang, Gangcai Xie, Hanzhi Zhao, Ying Jin, Beisha Tang, Yongchun Yu, Jian Zhao, and Gang Pei. Direct Conversion of Normal and Alzheimer's Disease Human Fibroblasts into Neuronal Cells by Small Molecules. Cell Stem Cell 17, 204-212, August 6, 2015.
2. Cal-520^®, AM. AAT Bioquest, n.d. Web. 1 July 2016