Purpose: The purpose of this study was to understand the genetic basis of differences in three forms of anthrax by studying the early transcriptomic gene expression profiling in human cutaneous (HEK001), gastrointestinal (Caco-2) and pulmonary (HBE4) cell lines 3 h after infection with the spores of an avirulent strain of B. anthracis.
Methods: Three independent RNA samples from spore-challenged and control groups were used for whole genome microarray analysis for each cell line. The raw data were normalized using 75% scaling and Student t-test was used to compute the significant gene list (P < 0.05 and fold change > 1.5).
Results: Analysis of the test vs control samples revealed cell-specific and common gene responses. Significantly up- (↑) and down-regulated (↓) cell-specific genes included 1164 genes (569↑/595↓) in HBE4, 985 genes (777↑/208↓) in HEK001, and 540 genes (191↑/259↓) in Caco-2 cells. There were 59 genes (55↑/4↓) that were commonly affected in all cell types. Pathway analyses showed that the most significantly affected functional groups were related to cell growth control, immune responses, genetic disorder, and apoptosis. Both cell-specific and common biomarkers were identified. Common biomarkers may account for the onset of anthrax and the cell-specific markers may account for differences in mortality rates of the three forms of anthrax.
Significance: The data has yielded important insights into the disease process and could potentially be used for developing improved and effective treatment options for anthrax, and in developing counter-terror measures.