Inflammatory Pathways in Spinal Cord Injury - International Review of Neurobiology - page 132

array of inflammatory mediators such as prostaglandins and leukotrienes, as
well as metabolites capable of inducing demyelination ( David, Greenhalgh,
& Lopez-Vales, 2012 ). We will discuss the identification and characterization
of their roles in SCI.

4.1. MAPK-activated protein kinase 2
This molecular target was identified from our Affymetrix microarray screen
of the contused spinal cord 7 days after injury, which corresponds to the peak
of the macrophage response ( Sroga et al., 2003 ). This screen identified al-
most 4500 differentially regulated genes, out of which 2300 were
upregulated and 2098 downregulated by 1.5-fold ( p < 0.05) in the contused
spinal cord relative to laminectomized controls ( Ghasemlou, Lopez-Vales,
et al., 2010 ). Genes of interest were identified by categorizing the up-
and downregulated genes according to function using Gene Ontology,
and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway
analyses. We found that the KEGG Pathways with the greatest numbers
of genes upregulated are primarily those involved in mediating the inflam-
matory response (see Table 5.1 ). The MAPK signaling pathway was of

Table 5.1 KEGG pathways with the highest number of genes upregulated by at least
1.5-fold and p < 0.05, relative to laminectomized controls, 7 days after spinal cord
contusion injury
KEGG pathway

No. of genes

Cytokine-cytokine receptor interaction 46

Focal adhesion 42

MAPK-signaling pathway 36

Regulation of actin cytoskeleton 29

ECM-receptor interaction 28

Leukocyte transendothelial migration 27

Cell adhesion molecules 25

Hematopoietic cell lineage 23

Toll-like receptor signaling pathway 23

Jak-STAT signaling pathway 22

B-cell receptor signaling pathway 22