Hypoxia protects neuronal cells from human prion protein fragment-induced apoptosis.
Prion diseases are neurodegenerative disorders characterized by the accumulation of an abnormal isoform of the prion protein PrP(Sc). Human prion protein fragment, PrP (106-126) (prion protein peptide 106-126), may contain most of the pathological features associated with PrP(Sc). Hypoxic conditions elicit cellular responses adaptively designed to improve cell survival and have an important role in the process of cell survival. We investigate the effects of hypoxia on PrP (106-126)-induced apoptosis in the present study. Human neuroblastoma and glioblastoma cells were incubated with varied doses of PrP (106-126) under both normoxic or hypoxic conditions, in order to determine the regulatory effects of hypoxia on PrP (106-126)-induced apoptosis. The results indicate that hypoxia protects neuronal cells against PrP (106-126)-induced cell death by activating the Akt signal, which is inactivated by prion proteins, and inhibiting PrP (106-126)-induced caspase 3 activation. Low oxygen conditions increase the Bcl-2 protein, which is associated with anti-apoptotic signals, and recover the PrP (106-126)-induced reduction in mitochondrial transmembrane potential. This study demonstrates that hypoxia inhibits PrP (106-126)-induced neuron cell death by regulating Akt and Akt-related signaling, and it also suggests that prion-related neuronal damage and disease may be regulated by hypoxia or by hypoxic-inducing genes.
Seo
Jae-Suk
JS
Center for Healthcare Technology Development, Korea Zoonoses Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk, South Korea.
Seol
Jae-Won
JW
Moon
Myung-Hee
MH
Jeong
Jae-Kyo
JK
Lee
You-Jin
YJ
Park
Sang-Youel
SY
D000704:Analysis of Variance; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D000860:Hypoxia; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D020287:In Situ Nick-End Labeling / Q000379:methods; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D009447:Neuroblastoma / Q000473:pathology; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D011328:Prions / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013778:Tetrazolium Salts; D013844:Thiazoles
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010446:Peptide Fragments; D011328:Prions; D019253:Proto-Oncogene Proteins c-bcl-2; D013778:Tetrazolium Salts; D013844:Thiazoles; C082632:prion protein (106-126); D051058:Oncogene Protein v-akt; D053148:Caspase 3; C022616:thiazolyl blue