Suppression of mitochondrial oxygen metabolism mediated by the transcription factor HIF-1 alleviates propofol-induced cell toxicity

Abstract

A line of studies strongly suggest that the intravenous anesthetic, propofol, suppresses mitochondrial oxygen metabolism. It is also indicated that propofol induces the cell death in a reactive oxygen species (ROS)-dependent manner. Because hypoxia-inducible factor 1 (HIF-1) is a transcription factor which is involved in cellular metabolic reprogramming by modulating gene expressions of enzymes including glycolysis pathway and oxygen utilization of mitochondria, we examined the functional role of HIF-1 activity in propofol-induced cell death. The role of HIF-1 activity on oxygen and energy metabolisms and propofol-induced cell death and caspase activity was examined in renal cell-derived RCC4 cells: RCC4-EV cells which lack von Hippel-Lindau protein (VHL) protein expression and RCC4-VHL cells, which express exogenous VHL, and in neuronal SH-SY5Y cells. It was demonstrated that HIF-1 is involved in suppressing oxygen consumption and facilitating glycolysis in cells and that the resistance to propofol-induced cell death was established in a HIF-1 activation-dependent manner. It was also demonstrated that HIF-1 activation by treatment with HIFα-hydroxylase inhibitors such as n-propyl gallate and dimethyloxaloylglycine, alleviated the toxic effects of propofol. Thus, the resistance to propofol toxicity was conferred by HIF-1 activation by not only genetic deletion of VHL but also exposure to HIFα-hydroxylase inhibitors.

Cancerous phenotypes associated with hypoxia-inducible factors are not influenced by the volatile anesthetic isoflurane in renal cell carcinoma

“…Total RNA was extracted from cells using RNeasy Mini Kit (Qiagen) [15,21], and FASTQ files were evaluated as described previously [15,21]. In brief, gene lists for Metascape analysis were generated from the Cuffdiff output file of significantly differentially expressed genes (p < 0.05; S1 Table).…”

“…The present results indicate that HIF activity is not influenced by the volatile anesthetic isoflurane.7.5% sodium dodecyl sulfate-polyacrylamide, gel electrophoresis and electro-transferred to membranes, probed with 1:2,000 of the indicated primary antibodies, probed with 1:8,000 of donkey anti-rabbit IgG (GE Healthcare, Piscataway, NJ) or sheep anti-mouse IgG (GE Healthcare) conjugated with horseradish peroxidase, and visualized with enhanced Chemi-Lumi One Super (Nacalai Tesque, Kyoto, Japan) (S1 Figure). Bands were quantified via densitometric analysis using Image Studio Lite (LI-COR Biosciences, Lincoln, NE, USA) [15,20,21]. Experiments were performed in triplicate, and representative blots are shown.…”

“…Cell growth was assessed using Proliferation Assay™ Kit in accordance with the manufacturer's instructions (Promega, Madison, WI, USA)[15,21,22]. Briefly, cells…”

Kinetic characteristics of propofol-induced inhibition of electron-transfer chain and fatty acid oxidation in human and rodent skeletal and cardiac muscles

“…The finding of the differences between human and rodent tissues exposed to propofol we consider very important for the interpretation of the experiments in animal models of PRIS [5,7,14,26,29,30]. On the other hand, the use of muscle homogenates only allows short term experimental exposure [17], which may not allow sufficient time for incorporation of propofol into the inner mitochondrial membrane [14] or affect gene expression [15,16]. Also, measuring parameters from the classic enzyme kinetics (such as Vmax or Km) may not be fully appropriate in systems that are likely multicompartmental and complex, such as bioenergetic pathways in mitochondria.…”

“…Vanlander et al in a study on rodents [14] first brought evidence for a hypothesis, that due to structural similarity of propofol and Coenzyme Q (CoQ), at least some effects of propofol on bioenergetics are caused by the inhibition of CoQ-dependent electron transfer pathways. Other mechanisms are possible, too, including metabolic rearrangement at translational level [15,16]. It is unknown whether increased concentration of substrates can overcome propofolinduced inhibition, a feature that would point towards competition of propofol with the respective substrate, or whether the presence of propofol influences the maximum flux through the ETC, which would point towards inhibition outside the substrate-binding sites of the enzymes or an interruption of electron flux through the respiratory chain, such as at the level of CoQ.…”