Anti-Apoptotic Effects of SERPIN B3 and B4 via STAT6 Activation in Macrophages after Infection with Toxoplasma gondii.
- Author:
Kyoung Ju SONG
1
;
Hye Jin AHN
;
Ho Woo NAM
Author Information
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords: Toxoplasma gondii; macrophage; SERPIN B3, B4; STAT6; anti-apoptosis
- MeSH: Animals; Antigens, Neoplasm/genetics/*metabolism; *Apoptosis; Cell Line; DNA Fragmentation; Humans; Macrophages/*cytology/metabolism; Mice; Mice, Inbred BALB C; STAT6 Transcription Factor/genetics/*metabolism; Serpins/genetics/*metabolism; Toxoplasma/genetics/*physiology; Toxoplasmosis/genetics/*metabolism/parasitology/*physiopathology
- From:The Korean Journal of Parasitology 2012;50(1):1-6
- CountryRepublic of Korea
- Language:English
- Abstract: Toxoplasma gondii penetrates all kinds of nucleated eukaryotic cells but modulates host cells differently for its intracellular survival. In a previous study, we found out that serine protease inhibitors B3 and B4 (SERPIN B3/B4 because of their very high homology) were significantly induced in THP-1-derived macrophages infected with T. gondii through activation of STAT6. In this study, to evaluate the effects of the induced SERPIN B3/B4 on the apoptosis of T. gondii-infected THP-1 cells, we designed and tested various small interfering (si-) RNAs of SERPIN B3 or B4 in staurosporine-induced apoptosis of THP-1 cells. Anti-apoptotic characteristics of THP-1 cells after infection with T. gondii disappeared when SERPIN B3/B4 were knock-downed with gene specific si-RNAs transfected into THP-1 cells as detected by the cleaved caspase 3, poly-ADP ribose polymerase and DNA fragmentation. This anti-apoptotic effect was confirmed in SERPIN B3/B4 overexpressed HeLa cells. We also investigated whether inhibition of STAT6 affects the function of SERPIN B3/B4, and vice versa. Inhibition of SERPIN B3/B4 did not influence STAT6 expression but SERPIN B3/B4 expression was inhibited by STAT6 si-RNA transfection, which confirmed that SERPIN B3/B4 was induced under the control of STAT6 activation. These results suggest that T. gondii induces SERPIN B3/B4 expression via STAT6 activation to inhibit the apoptosis of infected THP-1 cells for longer survival of the intracellular parasites themselves.
