1. mtDNA as a Mediator for Expression of Hypoxia-Inducible Factor 1 and ROS in Hypoxic Neuroblastoma Cells.
- Author
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Chung-Wen Kuo, Meng-Han Tsai, Tsu-Kung Lin, Mao-Meng Tiao, Pei-Wen Wang, Jiin-Haur Chuang, Shang-Der Chen, and Chia-Wei Liou
- Subjects
MITOCHONDRIAL DNA ,HYPOXIA-inducible factor 1 ,REACTIVE oxygen species ,HYPOXEMIA ,LACTATE dehydrogenase - Abstract
Mitochondria consume O2 to produce ATP and are critical for adaption of hypoxia, but the role of mitochondria in HIF-1α pathway is as yet unclear. In this study, mitochondrial DNA (mtDNA) enriched (SK-N-AS) and depleted ($0) cells of neuroblastoma were cultured in a hypoxic chamber to simulate a hypoxic condition and then the major components involved in mitochondrial related pathways, hypoxia-inducible factor 1α (HIF-1α) and reactive oxygen species (ROS) were measured. The results showed that hypoxia-stimulated exposure elevated expression of HIF-1α, which was additionally influenced by level of generated ROS within the cytosol. Moreover, elevation of HIF-1α also resulted in increases of lactate dehydrogenase A (LDH-A) and pyruvate dehydrogenase kinase 1 (PDK1) in both hypoxic cells. The expression of mitochondrial biogenesis related proteins and metabolic components were noted to increase significantly in hypoxic SK-N-AS cells, indicating that mtDNA was involved in mitochondrial retrograde signaling and metabolic pathways. An analysis of dynamic proteins found elevated levels of HIF-1α causing an increased expression of dynamin-related protein 1 (DRP1) during hypoxia; further, the existence of mtDNA also resulted in higher expression of DRP1 during hypoxia. By using siRNA of HIF-1α or DRP1, expression of DRP1 decreased after suppression of HIF-1α; moreover, the expression of HIF-1α was also affected by the suppression of DRP1. In this study, we demonstrated that mtDNA is a mediator of HIF-1α in eliciting metabolic reprogramming, and mitochondrial biogenesis. Identification of a mutual relationship between HIF-1v and DRP1 may be a critical tool in the future development of clinical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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