Triptolide Inhibited Cytotoxicity of Differentiated PC12 Cells Induced by Amyloid-Beta25–35 via the Autophagy Pathway

Abstract

Evidence shows that an abnormal deposition of amyloid beta-peptide25–35 (Aβ25–35) was the primary cause of the pathogenesis of Alzheimer’s disease (AD). And the elimination of Aβ25–35 is considered an important target for the treatment of AD. Triptolide (TP), isolated from Tripterygium wilfordii Hook.f. (TWHF), has been shown to possess a broad spectrum of biological profiles, including neurotrophic and neuroprotective effects. In our study investigating the effect and potential mechanism of triptolide on cytotoxicity of differentiated rat pheochromocytoma cell line (the PC12 cell line is often used as a neuronal developmental model) induced by Amyloid-Beta25–35 (Aβ25–35), we used 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay, flow cytometry, Western blot, and acridine orange staining to detect whether triptolide could inhibit Aβ25–35–induced cell apoptosis. We focused on the potential role of the autophagy pathway in Aβ25–35-treated differentiated PC12 cells. Our experiments show that cell viability is significantly decreased, and the apoptosis increased in Aβ25–35-treated differentiated PC12 cells. Meanwhile, Aβ25–35 treatment increased the expression of microtubule-associated protein light chain 3 II (LC3 II), which indicates an activation of autophagy. However, triptolide could protect differentiated PC12 cells against Aβ25–35-induced cytotoxicity and attenuate Aβ25–35-induced differentiated PC12 cell apoptosis. Triptolide could also suppress the level of autophagy. In order to assess the effect of autophagy on the protective effects of triptolide in differentiated PC12 cells treated with Aβ25–35, we used 3-Methyladenine (3-MA, an autophagy inhibitor) and rapamycin (an autophagy activator). MTT assay showed that 3-MA elevated cell viability compared with the Aβ25–35-treated group and rapamycin inhibits the protection of triptolide. These results suggest that triptolide will repair the neurological damage in AD caused by deposition of Aβ25–35 via the autophagy pathway, all of which may provide an exciting view of the potential application of triptolide or TWHF as a future research for AD.

Artemisinin protects PC12 cells against β-amyloid-induced apoptosis through activation of the ERK1/2 signaling pathway

“…In our present experiment, we explored whether artemisinin treatment could attenuate PC12 cells apoptosis due to Aβ25–35 exposure. In line with other reports, we found that Aβ25–35 was cytotoxicity to PC12 cells and showed a concentration-dependent manner [27]. In addition, data from Hoechst 33342 staining assay showed that the Aβ25–35 also induced the apoptosis of PC12 cells.…”

“…Previous studies reported that the toxicity of Aβ25-35 was mediated through the generation of ROS and our group also reported artemisinin can quench the ROS production [26], [27], [28]. Therefore, we investigated whether artemisinin blocked Aβ25-35-induced oxidative stress in PC12 cells.…”

Re-evaluation of Culture Condition of PC12 and SH-SY5Y Cells Based on Growth Rate and Amino Acid Consumption

“…We also found that treatment of amyloid peptides such as Aβ and Aβ 25-35 , nearly halved cell viability. The extent of sensitivity to amyloid peptides was similar to that of previously published values (9,11,12,13,15,18). These evidence suggests that the use of DMEM (supplemented with 10%FBS and antibiotics) is the best culture medium for both PC12 and SH-SY5Y cells.…”

Triptolide inhibits the function of TNF-α in osteoblast differentiation by inhibiting the NF-κB signaling pathway

“…Triptolide is one of the major active components extracted from the Thunder God Vine, Tripterygium wilfordii, and is a diterpenoid epoxide with molecular formula of C 20 H 24 O 6 (24)(25)(26). In the present study, it was indicated that 100 ng/ml BMP-2 was able to effectively stimulate the differentiation of bone cell precursors in the C2C12 cell line.…”