*Article* **Protective E**ff**ect of Fucoidan against MPP**<sup>+</sup>**-Induced SH-SY5Y Cells Apoptosis by A**ff**ecting the PI3K**/**Akt Pathway**

#### **Huaide Liu 1, Jing Wang 2,3,\*, Quanbin Zhang 2,3, Lihua Geng 2,3, Yue Yang 2,3 and Ning Wu 2,3**


Received: 9 May 2020; Accepted: 23 June 2020; Published: 25 June 2020

**Abstract:** The main pathologic changes of the Parkinson's disease (PD) is dopaminergic (DA) neurons lost. Apoptosis was one of the important reasons involved in the DA lost. Our previous study found a fucoidan fraction sulfated heterosaccharide (UF) had neuroprotective activity. The aim of this study was to clarify the mechanism of UF on DA neurons using human dopaminergic neuroblastoma (SH-SY5Y) cells a typical as a PD cellular model. Results showed that UF prevented MPP<sup>+</sup>-induced SH-SY5Y cells apoptosis and cell death. Additionally, UF pretreated cells increased phosphorylation of Akt, PI3K and NGF, which means UF-treated active PI3K–Akt pathway. Moreover, UF treated cells decreased the expression of apoptosis-associated protein, such as the ratio of Bax/Bcl-2, GSK3β, caspase-3 and p53 nuclear induced by MPP<sup>+</sup>. This effect was partially blocked by PI3K inhibitor LY294002. Our data suggested that protective effect of UF against MPP<sup>+</sup>-induced SH-SY5Y cells death by affecting the PI3K–Akt pathway. These findings contribute to a better understanding of the critical roles of UF in treating PD and may elucidate the molecular mechanisms of UF effects in PD.

**Keywords:** fucoidan; sulfated heterosaccharide; dopamine neurons apoptosis; PI3K–Akt
