Global Gene Expression Analysis to Unambiguously Identify Host Gene Responses Characteristic of Exposure to Biothreat Agents

摘要

We are studying the complex interaction between various biological pathogens and the host to understand the basis infectious or biothreat-induced diseases and to identify host defense strategies and the mechanisms by which they are regulated. Although gene response profiles show unique signatures quite rapidly after exposure, they also have the potential to reveal phases of progression of illness to (a) provide stage-specific diagnosis and (b) identification of potential molecular targets for stage appropriate therapeutic interventions for intractable illness induced by unconventional pathogenic agents. For this approach, several issues required prompt solutions including (a) establishment of a baseline for 'normal AND healthy' individuals (b) ability to fill in the gaps inherent in vivo studies with in vitro findings (c) differentiating biothreat induced flu-like illness from flu or other common illness (d) harnessing the power of prior knowledge to correlate with the global gene responses, (e) as well as certain other factors. We have used a library of 20,000 human cDNA ((caret)10,000 are known genes) to construct customized microarray chips used in these studies. We determined gene expression in human peripheral blood mononuclear cells (PBMC) in response to 15 pathogens at different time points in vitro (3-5 replicates). This provided a framework for us to then utilize responses in animal models that closely imitate the illness as it occurs in humans. For those studies, PBMC or whole blood were collected at various time points post exposure to track the primary, secondary and subsequent gene responses elicited by the pathogenic agents. The massive amounts of data are overwhelming but provide an incredibly rich source for both diagnostic and therapeutic approaches. The scientific community has realized the potential of these massive studies. Clever, far-reaching data mining approaches have been devised which we have utilized.