Background: Mesenchymal stem cells-conditioned medium (MSC-CM) provides a promising cell-free therapy for Alzheimer's disease (AD) mainly due to the paracrine of MSCs, but the precise mechanisms remain unclear. Studies suggests that mitochondrial dysfunction precedes the accumulation of amyloid-β plaques and neurofibrillary tangles, and involves in the onset and development of AD.
Objective: In the present study, we evaluated the protective effects and explored the related-mitochondrial mechanisms of human umbilical cord derived MSC-CM (hucMSC-CM) in an AD model in vitro.
Methods: To this end, an AD cellular model was firstly established by okadaic acid (OA)-treated SH-SY5Y cells, and then treated by hucMSC-CM to assess the oxidative stress, mitochondrial function, apoptosis, AD-related genes, and signaling pathways.
Results: hucMSC-CM significantly deceased tau phosphorylated at Thr181 (p181-tau) level, which was increased in AD. hucMSC-CM also alleviated intracellular and mitochondrial oxidative stress in OA-treated SH-SY5Y cells. In addition, hucMSC-CM suppressed apoptosis and improved mitochondrial function in OA-treated SH-SY5Y cells. Flow cytometric analysis indicated that hucMSC-CM exerted the protective effects relying on or partly extracellular vesicle (EV) mitochondrial transfer from hucMSCs to OA-treated SH-SY5Y cells. Moreover, RNA sequencing data further demonstrated that hucMSC-CM regulated many AD-related genes, signaling pathways and mitochondrial function.
Conclusion: These results indicated that MSC-CM or MSC-EVs containing abundant mitochondria may provide a novel potential therapeutic approach for AD.
Keywords: Alzheimer’s disease; apoptosis; mesenchymal stem cell-conditioned medium; mitochondrial dysfunction; mitochondrial transfer.