Complement component C5a induces aberrant epigenetic modifications in renal tubular epithelial cells accelerating senescence by Wnt4/βcatenin signaling after ischemia/reperfusion injury.

Giuseppe Castellano,Rossana Franzin,Paolo Cravedi,Antonio Crovace,Massimo Romani,Michele Battaglia,Francesco Staffieri,Giuseppe De Palma,Loreto Gesualdo,Barbara Banelli,Giuseppe Lucarelli,Giovanni Stallone,Alessandra Stasi,Fabio Sallustio,Pasquale Ditonno,Vincenzo Cantaluppi,Chiara Divella,Giuseppe Grandaliano

doi:10.18632/aging.102059

Abstract

Epigenetic mechanisms, such as DNA methylation, affect tubular maladaptive response after Acute Kidney Injury (AKI) and accelerate renal aging. Upon ischemia/reperfusion (I/R) injury, Complement activation leads to C5a release that mediates damage; however, little is known about the effect of C5a-C5a Receptor (C5aR) interaction in Renal Tubular Epithelial Cells (RTEC).Through a whole-genome DNA methylation analysis in cultured RTEC, we found that C5a induced aberrant methylation, particularly in regions involved in cell cycle control, DNA damage and Wnt signaling. The most represented genes were BCL9, CYP1B1 and CDK6. C5a stimulation of RTEC led to up-regulation of SA-β Gal and cell cycle arrest markers such as p53 and p21. C5a increased also IL-6, MCP-1 and CTGF gene expression, consistent with SASP development. In accordance, in a swine model of renal I/R injury, we found the increased expression of Wnt4 and βcatenin correlating with SA-β Gal, p21, p16 and IL-6 positivity. Administration of Complement Inhibitor (C1-Inh), antagonized SASP by reducing SA-β Gal, p21, p16, IL-6 and abrogating Wnt4/βcatenin activation.Thus, C5a affects the DNA methylation of genes involved in tubular senescence. Targeting epigenetic programs and Complement may offer novels strategies to protect tubular cells from accelerated aging and to counteract progression to Chronic Kidney Disease

Highlights

Acute Kidney Injury (AKI) is a frequent condition in hospitalized patients and is mainly caused by Ischemia/Reperfusion (I/R) injury, sepsis or nephrotoxic drugs [1]
These results indicated that gene expression of B-Cell CLL/Lymphoma 9 (BCL9), CYP1B1 and CDK6 is directly regulated by DNA methylation and that C5a is an epigenetic mediator that caused hypomethylation of genes that are involved, at least in part, in the Wnt/βcatenin signaling
We provide evidences that Complement anaphylatoxin C5a significantly triggers DNA methylation changes in renal tubular epithelial cells

Summary

Introduction

Acute Kidney Injury (AKI) is a frequent condition in hospitalized patients and is mainly caused by Ischemia/Reperfusion (I/R) injury, sepsis or nephrotoxic drugs [1]. The genome interacts with several environmental factors such as nutrients, pathogens, drugs and toxins that can modify the chromatin condensation to make specific genes accessible or not accessible to transcription factors, thereby extensively regulating gene expression. These modifications become stable and heritable upon mitosis and have been associated to the risk of AKI, allograft rejection after transplantation [7] or transition to CKD [8,9,10]. DNA methylation modifications have been shown to accelerate renal aging [12]; interestingly, hypermethylation of Klotho promoter, the principal anti-aging and renoprotective factor, led to a reduced Klotho gene expression with a significant association with CKD severity [10]

Objectives

Methods

Results

Conclusion