Sp110 transcription is induced and required by Anaplasma phagocytophilum for infection of human promyelocytic cells

de la Fuente J, Manzano-Roman R, Blouin EF, Naranjo V, Kocan KM
Source: BMC Infect Dis
Publication Date: (2007)
Issue: 7(1): 110
Research Area:
Immunotherapy / Hematology
Cells used in publication:
Species: human
Tissue Origin: blood
Nucleofector® I/II/2b
4D-Nucleofector® 96-well Systems
The expression of Sp110 was silenced in HL-60 cells using combination of two different siRNAs, and to actin-related protein 3 (ARP3) and P-selectin glycoprotein ligand-1 (PSGL-1). After nucleofection cells were divided into two 96-well plates, one for assessment of cell viability and morphology, the second for incubation with Anaplasma phagocytophilum.
BACKGROUND: The tick-borne intracellular pathogen, Anaplasma phagocytophilum (Rickettsiales: Anaplasmataceae) causes human granulocytic anaplasmosis after infection of polymorphonuclear leucocytes. The human Sp110 gene is a member of the nuclear body (NB) components that functions as a nuclear hormone receptor transcriptional coactivator and plays an important role in immunoprotective mechanisms against pathogens in humans. In this research, we hypothesized that Sp110 may be involved in the infection of human promyelocytic HL-60 cells with A. phagocytophilum. METHODS: The human Sp110 and A. phagocytophilum msp4 mRNA levels were evaluated by real-time RT-PCR in infected human HL-60 cells sampled at 0, 12, 24, 48, 72 and 96 hours post-infection. The effect of Sp110 expression on A. phagocytophilum infection was determined by RNA interference (RNAi). The expression of Sp110 was silenced in HL-60 cells by RNAi using pre-designed siRNAs using the Nucleofector 96-well shuttle system (Amaxa Biosystems, Gaithersburg, MD, USA). The A. phagocytophilum infection levels were evaluated in HL-60 cells after RNAi by real-time PCR of msp4 and normalizing against human Alu sequences. RESULTS: While Sp110 mRNA levels increased concurrently with A. phagocytophilum infections in HL-60 cells, the silencing of Sp110 expression by RNA interference resulted in decreased infection levels. CONCLUSIONS: These results demonstrated that Sp110 expression is required for A. phagocytophilum infection and multiplication in HL-60 cells, and suggest a previously undescribed mechanism by which A. phagocytophilum modulates Sp110 mRNA levels to facilitate establishment of infection of human HL-60 cells.