Sp110 transcription is induced and required by Anaplasma phagocytophilum for infection of human promyelocytic cells.
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.
de la Fuente
José
J
Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA. jose.de_la_fuente@okstate.edu
Manzano-Roman
Raúl
R
Blouin
Edmour F
EF
Naranjo
Victoria
V
Kocan
Katherine M
KM
D041081:Anaplasma phagocytophilum / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D000712:Anaplasmosis / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D042381:Granulocyte Precursor Cells / Q000378:metabolism* / Q000382:microbiology* / Q000502:physiology; D018922:HL-60 Cells; D006801:Humans; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014158:Transcription, Genetic; D015047:Zoonoses
D001426:Bacterial Proteins; D015778:Minor Histocompatibility Antigens; D009687:Nuclear Proteins; D012333:RNA, Messenger; C412425:Sp110 protein, human