Parathyroid hormone(1-34)-induced apoptosis in neuronal rat PC12 cells: implications for neurotoxicity.
Based on accumulated evidence, we speculate that a high concentration of parathyroid hormone (PTH) may cause neurotoxicity in patients with uremia through apoptosis-induced neuropathy. In this study, we demonstrated that in vitro stimulation with PTH(1-34) induced a significant decrease in PC12 cell numbers in both dosage- and time-dependent fashions when these cells were treated with PTH(1-34) at concentrations of 0.01, 0.1 or 1.0 μM for 24, 48, 72, and 96 h, respectively, as assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Decreased numbers of PC12 cells were caused by PTH(1-34)-induced apoptotic and cytotoxic processes, as determined by DNA fragmentation, flow cytometry, and lactate dehydrogenase (LDH)-leakage assays. Upregulation of the extracellular signal-regulated kinase (ERK) and p38 signaling pathway was the underlying mechanism responsible for 1.0 μM PTH(1-34)-induced apoptosis in PC12 cells, as elucidated by Western blotting analysis and confirmed with ERK and p38 inhibitors. Furthermore, 1.0 μM PTH(1-34)-induced apoptosis was accompanied by a release of cytochrome c and subsequent caspase-3 activation. These data suggest that a high concentration of PTH(1-34)-induced cytotoxicity and apoptosis in PC12 cells was associated with upregulation of ERK and p38 through a mitochondria-mediated apoptotic pathway.
An
Hui-Xia
HX
Department of Nephrology, The Second Affiliated Hospital, Harbin Medical University, Nan-gang District, Harbin, People's Republic of China.
Jin
Zhan-Feng
ZF
Ge
Xiao-Feng
XF
Wu
Jing
J
Chen
Chang
C
Zhang
Feng-Min
FM
Qu
Wei
W
Liu
Xiao-Gang
XG
Liu
Su-Yan
SY
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival; D045304:Cytochromes c / Q000378:metabolism*; D053938:DNA Fragmentation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005419:Flavonoids / Q000037:antagonists & inhibitors; D005434:Flow Cytometry; D007093:Imidazoles / Q000037:antagonists & inhibitors; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D016716:PC12 Cells; D010281:Parathyroid Hormone / Q000009:adverse effects* / Q000378:metabolism / Q000494:pharmacology*; D011725:Pyridines / Q000037:antagonists & inhibitors; D051381:Rats; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D005419:Flavonoids; D007093:Imidazoles; D010281:Parathyroid Hormone; D011725:Pyridines; D045304:Cytochromes c; D007770:L-Lactate Dehydrogenase; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C505410:Casp3 protein, rat; D053148:Caspase 3; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one