Gene Expression Profile of THP-1 Cells Infected by R. prowazekii Suggests Host Response Signature Genes

Abstract

Rickettsia prowazekii, a selective agent of category B, is the causative microorganism of epidemic typhus. The genome-wide profile of host response to R. prowazekii infection was studied in THP-1 cells by a human cDNA microarray. Approximately 131 (1.71%) and 11 (0.14%) genes out of 7,680 genes assessed were up-regulated or down-regulated upon infection with virulent R. prowazekii strain Breinl. These genes induced by R. prowazekii were diverse in function. Six genes [ENG (endoglin or CD105, cell surface glycoprotein), GADD45A, TNFAIP3, IGFBP3, POU3F4 (transcription), ELK3] were identified as commonly induced genes as their over expressions were observed throughout the entire time course studied. There were twenty-two genes [such as GADD45A, POU3F4, ENG, PPP1R14B (an enzyme), ELK3, CXCL1, IL1B, NFKB1A, etc.] that exhibited the high level of induction at more than one time point. Collectively, these discoveries may provide novel insights into mechanisms of rickettsial pathogenesis and might reveal potential therapeutic targets against rickettsial infection.