Global Lysine Acetylome Analysis of LPS-Stimulated HepG2 Cells Identified Hyperacetylation of PKM2 as a Metabolic Regulator in Sepsis

Ann-Yae Na,Soyoung Choi,Jong-Sup Bae,Sangkyu Lee,Sanjita Paudel,Jun Hyung Lee,Min-Sik Kim

doi:10.3390/ijms22168529

Abstract

Sepsis-induced liver dysfunction (SILD) is a common event and is strongly associated with mortality. Establishing a causative link between protein post-translational modification and diseases is challenging. We studied the relationship among lysine acetylation (Kac), sirtuin (SIRTs), and the factors involved in SILD, which was induced in LPS-stimulated HepG2 cells. Protein hyperacetylation was observed according to SIRTs reduction after LPS treatment for 24 h. We identified 1449 Kac sites based on comparative acetylome analysis and quantified 1086 Kac sites on 410 proteins for acetylation. Interestingly, the upregulated Kac proteins are enriched in glycolysis/gluconeogenesis pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG) category. Among the proteins in the glycolysis pathway, hyperacetylation, a key regulator of lactate level in sepsis, was observed at three pyruvate kinase M2 (PKM2) sites. Hyperacetylation of PKM2 induced an increase in its activity, consequently increasing the lactate concentration. In conclusion, this study is the first to conduct global profiling of Kac, suggesting that the Kac mechanism of PKM2 in glycolysis is associated with sepsis. Moreover, it helps to further understand the systematic information regarding hyperacetylation during the sepsis process.

Highlights

Sepsis, a life-threatening complication, occurs when the body’s response to infection causes injuries to tissues and organs
In the SIRT family, the role of SIRT1 in sepsis was reported in the most diverse manner, wherein the SIRT1 activation inhibits the inflammatory response caused by sepsis
As SIRT1 is an NAD+ -dependent deacetylase, when SIRT1 is reduced in LPS-induced sepsis-induced liver dysfunction (SILD) in HepG2 cells, the substrate proteins hyperacetylate, playing an essential role in the progression of inflammation

Summary

Introduction

A life-threatening complication, occurs when the body’s response to infection causes injuries to tissues and organs. During the initial stage of the disease, almost all patients with sepsis exhibit excessive hyperinflammation characterized by a cytokine storm, overproduction of reactive oxygen species, and metabolic shift [1]. Liver dysfunction during sepsis is one of the components of multiple organ dysfunction syndrome and is usually associated with a poor prognosis. Sepsis can cause impaired liver function, contributing to the high mortality associated with sepsis. Liver dysfunction represents a specific and independent risk factor for poor prognosis in critically ill patients [6], prone to developing sepsis, sepsis-associated organ failure, and death owing to pre-existing liver disease [7]

Methods

Results

Conclusion