PEG35 as a Preconditioning Agent against Hypoxia/Reoxygenation Injury.

Rui Teixeira da Silva,Anabela P. Rolo,Joan Roselló-Catafau,Ivo F. Machado,João S. Teodoro,Carlos M. Palmeira,Arnau Panisello-Roselló

doi:10.3390/ijms23031156

Abstract

Pharmacological conditioning is a protective strategy against ischemia/reperfusion injury, which occurs during liver resection and transplantation. Polyethylene glycols have shown multiple benefits in cell and organ preservation, including antioxidant capacity, edema prevention and membrane stabilization. Recently, polyethylene glycol 35 kDa (PEG35) preconditioning resulted in decreased hepatic injury and protected the mitochondria in a rat model of cold ischemia. Thus, the study aimed to decipher the mechanisms underlying PEG35 preconditioning-induced protection against ischemia/reperfusion injury. A hypoxia/reoxygenation model using HepG2 cells was established to evaluate the effects of PEG35 preconditioning. Several parameters were assessed, including cell viability, mitochondrial membrane potential, ROS production, ATP levels, protein content and gene expression to investigate autophagy, mitochondrial biogenesis and dynamics. PEG35 preconditioning preserved the mitochondrial function by decreasing the excessive production of ROS and subsequent ATP depletion, as well as by recovering the membrane potential. Furthermore, PEG35 increased levels of autophagy-related proteins and the expression of genes involved in mitochondrial biogenesis and fusion. In conclusion, PEG35 preconditioning effectively ameliorates hepatic hypoxia/reoxygenation injury through the enhancement of autophagy and mitochondrial quality control. Therefore, PEG35 could be useful as a potential pharmacological tool for attenuating hepatic ischemia/reperfusion injury in clinical practice.

Highlights

IntroductionSeveral parameters were assessed, including cell viability, mitochondrial membrane potential, ROS production, ATP levels, protein content and gene expression to investigate autophagy, mitochondrial biogenesis and dynamics
To examine the effect of polyethylene glycol 35 kDa (PEG35) preconditioning against hypoxia/reoxygenation injury, cell viability was assessed through the reduction of a yellow tetrazolium salt to purple formazan crystals
The HepG2 pretreated with 5% PEG35 for 1 h and subjected to 2 h of hypoxia followed by 2 h of reoxygenation demonstrated significantly higher cell viability compared to cells that did not receive PEG preconditioning (Figure 1b)

Summary

Introduction

Several parameters were assessed, including cell viability, mitochondrial membrane potential, ROS production, ATP levels, protein content and gene expression to investigate autophagy, mitochondrial biogenesis and dynamics. Mitochondria are crucial players in every single living eukaryote In addition to their well-established role in energetic metabolism and ATP generation, mitochondria participate in many other physiological functions, including catabolic and anabolic processes, diverse signaling pathways, calcium homeostasis and cell death mechanisms [5]. Disruptions to these processes affect normal mitochondrial function, and disruptions have published maps and institutional affiliations

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