Global Proteome and Phosphoproteome Characterization of Sepsis-induced Kidney Injury

Yi-Han Lin,Maryann P Platt,Haiyan Fu,Yuan Gui,Yanlin Wang,Norberto Gonzalez-Juarbe,Dong Zhou,Yanbao Yu

doi:10.1074/mcp.ra120.002235

Abstract

Sepsis-induced acute kidney injury (S-AKI) is the most common complication in hospitalized and critically ill patients, highlighted by a rapid decline of kidney function occurring a few hours or days after sepsis onset. Systemic inflammation elicited by microbial infections is believed to lead to kidney damage under immunocompromised conditions. However, although AKI has been recognized as a disease with long-term sequelae, partly because of the associated higher risk of chronic kidney disease (CKD), the understanding of kidney pathophysiology at the molecular level and the global view of dynamic regulations in situ after S-AKI, including the transition to CKD, remains limited. Existing studies of S-AKI mainly focus on deriving sepsis biomarkers from body fluids. In the present study, we constructed a mid-severity septic murine model using cecal ligation and puncture (CLP), and examined the temporal changes to the kidney proteome and phosphoproteome at day 2 and day 7 after CLP surgery, corresponding to S-AKI and the transition to CKD, respectively, by employing an ultrafast and economical filter-based sample processing method combined with the label-free quantitation approach. Collectively, we identified 2,119 proteins and 2950 phosphosites through multi-proteomics analyses. Among them, we identified an array of highly promising candidate marker proteins indicative of disease onset and progression accompanied by immunoblot validations, and further denoted the pathways that are specifically responsive to S-AKI and its transition to CKD, which include regulation of cell metabolism regulation, oxidative stress, and energy consumption in the diseased kidneys. Our data can serve as an enriched resource for the identification of mechanisms and biomarkers for sepsis-induced kidney diseases.

Highlights

Sepsis-induced acute kidney injury (S-Acute kidney injury (AKI)) is the most common complication in hospitalized and critically ill patients, highlighted by a rapid decline of kidney function occurring a few hours or days after sepsis onset
We identified an array of highly promising candidate marker proteins indicative of disease onset and progression accompanied by immunoblot validations, and further denoted the pathways that are responsive to Sepsis-induced acute kidney injury (S-AKI) and its transition to chronic kidney disease (CKD), which include regulation of cell metabolism regulation, oxidative stress, and energy consumption in the diseased kidneys
Characterization of Kidney Injury after S-AKI—Given that SAKI is the most common complication associated with sepsis in the clinic, we aimed to explore its pathogenesis in detail

Summary

Introduction

Sepsis-induced acute kidney injury (S-AKI) is the most common complication in hospitalized and critically ill patients, highlighted by a rapid decline of kidney function occurring a few hours or days after sepsis onset. Tubular endothelial cells are equipped with pattern recognition receptors (such as Toll-like receptors, TLRs), which can receive signals from sepsis-induced inflammation, pathogen-associated molecular patterns (PAMPs), or damageassociated molecular patterns (DAMPs) These result in a cascade of downstream signals and increase the synthesis of proinflammatory cytokines, reactive oxygen species, and oxidative stress that damage renal tubular cells [4, 8, 9]. The global changes of the diseased kidneys after S-AKI at the molecular level remain largely unknown In this regard, we constructed an S-AKI mouse model using the cecal ligation and puncture (CLP) procedure. CLP is a gold standard clinical model [12] as it allows the release of fecal components into the peritoneal cavity and circulatory system that induces exacerbated inflammatory responses This procedure mimics gut injury-triggered severe sepsis in humans. With the results we obtained, we can better characterize the molecular mechanisms underlying the development of S-AKI and its transition to CKD

Objectives

Results

Conclusion