Hypoxic regulation of NF-kappaB signaling.

Hypoxia and inflammation are coincidental events in an array of diseased tissues, including chronically inflamed sites (e.g., inflammatory bowel disease, rheumatoid arthritis), growing tumors, myocardial infarcts, atherosclerotic plaques, healing wounds, and sites of bacterial infection (Murdoch et al., 2005). An understanding of how hypoxia modulates the inflammatory response is critical in developing our fundamental understanding of inflammatory disease and identifying new windows of therapeutic opportunity. Nuclear factor-kappaB (NF-kappaB) is a master transcriptional regulator of inflammatory and antiapoptotic gene expression, the activation of which has significant implications in disease development. Recent work has uncovered mechanisms by which hypoxia modulates the activation of NF-kappaB in cells through decreased oxygen-dependent suppression of the key regulators of this pathway. This work has implicated a novel role for proline and asparagine hydroxylases in the modulation of NF-kappaB activity. Here, we describe methodologies used to demonstrate and interrogate hypoxic induction of the NF-kappaB pathway.