Knockdown of STIM1 inhibits 6-hydroxydopamine-induced oxidative stress through attenuating calcium-dependent ER stress and mitochondrial dysfunction in undifferentiated PC12 cells.
Stromal interaction molecule (STIM) proteins are parts of elaborate eukaryotic Ca(2+) signaling systems and are considered to be important players in regulating neuronal Ca(2+) homeostasis under normal ageing and pathological conditions. Here, we investigated the potential role of STIM1 in 6-hydroxydopamine (6-OHDA)-induced toxicity in undifferentiated PC12 cell lines. Cells exposed to 6-OHDA demonstrated alterations in the generation of reactive oxygen species (ROS) in a Ca(2+)-dependent manner. Downregulation of STIM1 expression by specific small interfering RNA (siRNA) attenuated apoptotic cell death, reduced intracellular ROS production, and partially prevented the impaired endogenous antioxidant enzyme activities after 6-OHDA treatment. Furthermore, STIM1 knockdown significantly attenuated 6-OHDA-induced intracellular Ca(2+) overload by inhibiting endogenous store-operated calcium entry (SOCE). The effect of STIM1 siNRA on SOCE was related to orai1 and L-type Ca(2+) channels, but not to transient receptor potential canonical type 1 (TRPC1) channel. In addition, silencing of STIM1 increased the Ca(2+) buffering capacity of the endoplasmic reticulum (ER) in 6-OHDA-injured cells. ER vacuoles formed from the destruction of ER structural integrity and activation of ER-related apoptotic factors (CHOP and Caspase-12) were partially prevented by STIM1 knockdown. Moreover, STIM1 knockdown attenuated 6-OHDA-induced mitochondrial Ca(2+) uptake and mitochondrial dysfunction, including the collapse of mitochondrial membrane potential (MMP) and the decrease of ATP generation. Taken together, our data provide the first evidence that inhibition of STIM1-meditated intracellular Ca(2+) dyshomeostasis protects undifferentiated PC12 cells against 6-OHDA toxicity and indicate that STIM1 may be responsible for neuronal oxidative stress induced by ER stress and mitochondrial dysfunction in PD.
Department of Reproductive Medicine, the First Affiliated Hospital of Medical School, Xi'an Jiaotong University , Xi'an, Shaanxi , The People's Republic of China.
B
B
Li
L
L
Xiao
Z Y
ZY
Wang
P S
PS
Zheng
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008562:Membrane Glycoproteins / Q000172:deficiency* / Q000235:genetics; D008928:Mitochondria / Q000187:drug effects* / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D016627:Oxidopamine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D016716:PC12 Cells; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D000071737:Stromal Interaction Molecule 1
D008562:Membrane Glycoproteins; D034741:RNA, Small Interfering; C518857:Stim1 protein, rat; D000071737:Stromal Interaction Molecule 1; D016627:Oxidopamine; D002118:Calcium
ER stress; STIM1; mitochondrial dysfunction; reactive oxygen species; store-operated calcium entry