Astaxanthin Suppresses MPP+-Induced Oxidative Damage in PC12 Cells through a Sp1/NR1 Signaling Pathway

Abstract

Objective: To investigate astaxanthin (ATX) neuroprotection, and its mechanism, on a 1-methyl-4-phenyl-pyridine ion (MPP+)-induced cell model of Parkinson’s disease. Methods: Mature, differentiated PC12 cells treated with MPP+ were used as an in vitro cell model. The MTT assay was used to investigate cell viability after ATX treatment, and western blot analysis was used to observe Sp1 (activated transcription factor 1) and NR1 (NMDA receptor subunit 1) protein expression, real-time PCR was used to monitor Sp1 and NR1 mRNA, and cell immunofluorescence was used to determine the location of Sp1 and NR1 protein and the nuclear translocation of Sp1. Results: PC12 cell viability was significantly reduced by MPP+ treatment. The expression of Sp1 and NR1 mRNA and protein were increased compared with the control (p < 0.01). Following co-treatment with ATX and MPP+, cell viability was significantly increased, and Sp1 and NR1 mRNA and protein were decreased, compared with the MPP+ groups (p < 0.01). In addition, mithracycin A protected PC12 cells from oxidative stress caused by MPP+ by specifically inhibiting the expression of Sp1. Moreover, cell immunofluorescence revealed that ATX could suppress Sp1 nuclear transfer. Conclusion: ATX inhibited oxidative stress induced by MPP+ in PC12 cells, via the SP1/NR1 signaling pathway.

MPTP’s Pathway of Toxicity Indicates Central Role of Transcription Factor SP1

“…ZNF148, however, is known to play a role in apoptosis (Zhang et al 2010), is verified by proteomic studies as expressed in the substantia nigra (Chen et al 2012) and would be an interesting candidate for further study. ATF4, which has recently been identified by us and others in independent high-throughput studies as a key transcriptional factor in MPTP toxicity (Ye et al 2013, Krug et al 2014), was also present as a small hub containing mostly protein–protein interaction connections in the network when restricted to experimentally verified interactions. Similarly, TCF3 had relatively few experimentally verified reactions and is thus relatively small in the graph; however, an expanded subnetwork that included predicted transcription factor binding sites, even when restricted to a high stringency level, would have been substantially larger.…”

“…However, SP1 protein and mRNA levels have been shown to increase following MPP+ dosing in PC12 cells by approximately 1.5-fold, which was blocked by antioxidant treatment (Ye et al 2013). The lack of appearance of SP1 among the genes differentially expressed or in the modules may simply reflect that SP1 mRNA rises only modestly (or perhaps briefly); alternatively, it is regulated by means other than an increase in mRNA levels and the signal increase is therefore nonlinear compared to mRNA levels (Courey et al 1989).…”

Astaxanthin as a Potential Neuroprotective Agent for Neurological Diseases

“…In addition, astaxanthin enhanced HO-1 expression and limited NADPH oxidase 2 (NOX2)-mediated oxidative damage in MPP + -treated PC12 cells [ 62 ]. Astaxanthin antagonized MPP + -induced oxidative stress through the regulation of specificity protein 1 (Sp1) and NMDA receptor subunit 1 (NR1) signaling pathway [ 63 ]. Pre-treatment with astaxanthin markedly inhibited the up-regulation and nuclear transfer of Sp1, thereby alleviated MPP + -induced production of intracellular ROS and cytotoxicity in PC12 cells [ 63 ].…”

Calcium-Involved Action of Phytochemicals: Carotenoids and Monoterpenes in the Brain

“…MPP+ (n-methyl-4-phenylpyridinium iodide) is the toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a well-established and commonly used substance used in the toxic model of Parkinson's disease. In the presence of AXT, PC12 cell viability was significantly increased, and Sp1 (activated transcription factor-1) and NR1 decreased at the mRNA and protein levels compared to in the MPP+ groups without AXT [38].…”