Kinase Activity Profiling of Pneumococcal Pneumonia

Jose Chabalgoity,Arie J Hoogendijk,Tom Van Der Poll,Catharina W Wieland,Sander H Diks,Maikel P Peppelenbosch

doi:10.1371/journal.pone.0018519

Abstract

BackgroundPneumonia represents a major health burden. Previous work demonstrated that although the induction of inflammation is important for adequate host defense against pneumonia, an inability to regulate the host's inflammatory response within the lung later during infection can be detrimental. Intracellular signaling pathways commonly rely on activation of kinases, and kinases play an essential role in the regulation of the inflammatory response of immune cells.Methodology/Principal FindingsPneumonia was induced in mice via intranasal instillation of Streptococcus (S.) pneumoniae. Kinomics peptide arrays, exhibiting 1024 specific consensus sequences for protein kinases, were used to produce a systems biology analysis of cellular kinase activity during the course of pneumonia. Several differences in kinase activity revealed by the arrays were validated in lung homogenates of individual mice using western blot. We identified cascades of activated kinases showing that chemotoxic stress and a T helper 1 response were induced during the course of pneumococcal pneumonia. In addition, our data point to a reduction in WNT activity in lungs of S. pneumoniae infected mice. Moreover, this study demonstrated a reduction in overall CDK activity implying alterations in cell cycle biology.Conclusions/SignificanceThis study utilizes systems biology to provide insight into the signaling events occurring during lung infection with the common cause of community acquired pneumonia, and may assist in identifying novel therapeutic targets in the treatment of bacterial pneumonia.

Highlights

Due to its unique relationship with the environment, the lung must defend itself from infection by numerous inhaled microorganisms
Bacterial pneumonia First, we determined the course of bacterial infection
Between 6 and 24 hours bacterial loads in the lung increased exponentially. At this time an apparent maximum number of bacteria had been reached in the lung compartment, as no further increase was detected at 48 hours

Summary

Introduction

Due to its unique relationship with the environment, the lung must defend itself from infection by numerous inhaled microorganisms. The Grampositive bacterium S. pneumoniae is the main causative pathogen in community-acquired pneumonia (CAP), responsible for an estimated ten million deaths annually worldwide [1,2,3]. Recognition of invading bacteria by the host is considered to occur mainly through toll-like receptors (TLRs). After interacting with their ligands, TLRs signal via adaptor proteins and kinases to activate Nuclear factor-kB (NF-kB) inducing inflammatory responses [7]. The interactions between bacteria and host cells are not confined to TLRs and ongoing intracellular signaling cascades may be much more extensive and complex than generally thought. Intracellular signaling pathways commonly rely on activation of kinases, and kinases play an essential role in the regulation of the inflammatory response of immune cells

Methods

Results

Conclusion