Central role for MCP-1/CCL2 in injury-induced inflammation revealed by in vitro, in silico, and clinical studies

PLoS One. 2013 Dec 3;8(12):e79804. doi: 10.1371/journal.pone.0079804. eCollection 2013.

Abstract

The translation of in vitro findings to clinical outcomes is often elusive. Trauma/hemorrhagic shock (T/HS) results in hepatic hypoxia that drives inflammation. We hypothesize that in silico methods would help bridge in vitro hepatocyte data and clinical T/HS, in which the liver is a primary site of inflammation. Primary mouse hepatocytes were cultured under hypoxia (1% O2) or normoxia (21% O2) for 1-72 h, and both the cell supernatants and protein lysates were assayed for 18 inflammatory mediators by Luminex™ technology. Statistical analysis and data-driven modeling were employed to characterize the main components of the cellular response. Statistical analyses, hierarchical and k-means clustering, Principal Component Analysis, and Dynamic Network Analysis suggested MCP-1/CCL2 and IL-1α as central coordinators of hepatocyte-mediated inflammation in C57BL/6 mouse hepatocytes. Hepatocytes from MCP-1-null mice had altered dynamic inflammatory networks. Circulating MCP-1 levels segregated human T/HS survivors from non-survivors. Furthermore, T/HS survivors with elevated early levels of plasma MCP-1 post-injury had longer total lengths of stay, longer intensive care unit lengths of stay, and prolonged requirement for mechanical ventilation vs. those with low plasma MCP-1. This study identifies MCP-1 as a main driver of the response of hepatocytes in vitro and as a biomarker for clinical outcomes in T/HS, and suggests an experimental and computational framework for discovery of novel clinical biomarkers in inflammatory diseases.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Animals
  • Biomarkers / blood
  • Case-Control Studies
  • Cell Hypoxia
  • Chemokine CCL2 / blood*
  • Disease-Free Survival
  • Female
  • Hep G2 Cells
  • Hepatocytes / metabolism
  • Hepatocytes / pathology
  • Humans
  • Inflammation / blood
  • Inflammation / mortality
  • Interleukin-1alpha / blood
  • Male
  • Mice
  • Mice, Knockout
  • Middle Aged
  • Shock, Hemorrhagic / blood*
  • Shock, Hemorrhagic / mortality*
  • Survival Rate
  • Wounds and Injuries / blood*
  • Wounds and Injuries / mortality*

Substances

  • Biomarkers
  • CCL2 protein, human
  • Ccl2 protein, mouse
  • Chemokine CCL2
  • IL1A protein, human
  • Interleukin-1alpha