Light‐controlled astrocytes promote human mesenchymal stem cells toward neuronal differentiation and improve the neurological deficit in stroke rats

Abstract

Astrocytes are key components of the central nervous system (CNS) and release factors to support neural stem cell proliferation, differentiation, and migration. Adenosine 5'-triphosphate (ATP) is one of the key factors released upon activation of astrocytes that regulates the neural stem cell's function. However, it is not clear whether ATP derived from the depolarized astrocytes plays a vital role in promoting the neuronal differentiation of mesenchymal stem cells (MSCs) in vitro and in vivo. Herein, for the first time, we co-cultured MSCs with light-stimulated-channelrhodopsin-2 (ChR2)-astrocytes, and observed that the neuronal differentiation of MSCs was enhanced by expressing more neuronal markers, Tuj1 and NeuN. The ChR2-astrocyte-conditioned medium also stimulated MSCs differentiating into neuronal lineage cells by expressing more Tuj1 and Pax6, which was blocked by the P2X receptor antagonist, TNP-ATP. Then we found that light-depolarization of astrocytes significantly increased ATP accumulation in their bathing medium without impairing the cell membrane. We further found that ATP up-regulated the Tuj1, Pax6, FZD8 and β-catenin mRNA levels of MSCs, which could be reversed by application of TNP-ATP. Together these in vitro data provided convergent evidence that ATP from light-depolarized-astrocytes activated the wnt/β-catenin signaling of MSCs through binding to the P2X receptors, and promoted the neuronal differentiation of MSCs. Finally but importantly, our study also demonstrated in stroke rats that light-controlled astrocytes stimulated endogenous ATP release into the ischemic area to influence the transplanted MSCs, resulting in promoting the MSCs towards neuronal differentiation and improvements of neurological deficit.

Stem cell therapy for abrogating stroke-induced neuroinflammation and relevant secondary cell death mechanisms

“…Furthermore, PL has been shown to provide an increase to the growth rates of MSC populations grown outside of fetal bovine serum, while still ensuring the chromosomal stability of the cell line over multiple generation. Moreover, additional trophic factors which improve the proliferation and differentiation of BM-MSCs into neurons and neuron-like cells in vitro have been identified, including melatonin, ATP, neurotrophin-3 (NT-3), rolipram, β-mercaptoethanol (BME), CHIR99021 (CHIR), lithium chloride, and others (Tu et al, 2014; Abdullah et al, 2016; Joe and Cho, 2016; Narcisi et al, 2016; Shuai et al, 2016; Yan et al, 2016). Co-culturing BM-MSCs with active neurons or culturing BM-MSCs on media conditioned by mature neurons also appears to promote their differentiation towards neural cell types (Tu et al, 2014; Kil et al, 2016).…”

“…Moreover, additional trophic factors which improve the proliferation and differentiation of BM-MSCs into neurons and neuron-like cells in vitro have been identified, including melatonin, ATP, neurotrophin-3 (NT-3), rolipram, β-mercaptoethanol (BME), CHIR99021 (CHIR), lithium chloride, and others (Tu et al, 2014; Abdullah et al, 2016; Joe and Cho, 2016; Narcisi et al, 2016; Shuai et al, 2016; Yan et al, 2016). Co-culturing BM-MSCs with active neurons or culturing BM-MSCs on media conditioned by mature neurons also appears to promote their differentiation towards neural cell types (Tu et al, 2014; Kil et al, 2016). For example, hBM-MSCs co-cultured with astrocytes displayed a significant tendency to differentiate into neural lineages, while hBM-MCSs cultured on media conditioned by choroid plexus epithelial cells showed higher rates of induction toward dopaminergic cell types than controls (Tu et al, 2014; Aliaghaei et al, 2016).…”

“…Co-culturing BM-MSCs with active neurons or culturing BM-MSCs on media conditioned by mature neurons also appears to promote their differentiation towards neural cell types (Tu et al, 2014; Kil et al, 2016). For example, hBM-MSCs co-cultured with astrocytes displayed a significant tendency to differentiate into neural lineages, while hBM-MCSs cultured on media conditioned by choroid plexus epithelial cells showed higher rates of induction toward dopaminergic cell types than controls (Tu et al, 2014; Aliaghaei et al, 2016). Biomaterials also have been investigated for their potential role in improving BM-MSC proliferation and increasing the efficacy of their transplantation.…”

Brain mesenchymal stem cells: The other stem cells of the brain?

“…For example, they can transdifferentiate into urothelial, myocardial, and epithelial cells [19][20][21] . Numerous studies also report the in vitro transdifferentiation of MSCs into neural and glial cells [22][23][24][25][26][27][28][29][30] . At the moment, the potential of MSCs to regenerate human tissues in vivo is not clearly defined.…”

Optogenetic manipulation of astrocytes from synapses to neuronal networks: A potential therapeutic strategy for neurodegenerative diseases

“…There are seldom effective drugs for targeting astrocyte‐neuron interactions to treat NDs so far. Pioneering studies applied optogenetics on astrocytes to regulate brain function via inducing endogenous gliotransmitters (Adamsky et al, ; Gourine et al, ; Masamoto et al, ; Perea, Yang, Boyden, & Sur, ; Sasaki et al, ; Tu et al, ; Yamashita et al, ; Yang et al, ). Selective expression and photostimulation of channelrhodopsin 2 (ChR2) in astrocytes leads to increased calcium influx over milliseconds, which leads to activation of downstream signaling pathways in astrocytes and the subsequent release of cytokines and gliotransmitters that in turn influence activity of adjacent neurons in cultural cells and in vivo models (Almad & Maragakis, ).…”