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Pyroptosis is induced by Streptococcus pneumoniae in microglial cells
Author(s) -
Jung Yun Joo,
Lee Hee Weon
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.766.16
Subject(s) - pyroptosis , caspase 1 , streptococcus pneumoniae , cell culture , pneumolysin , inflammasome , biology , microbiology and biotechnology , western blot , programmed cell death , apoptosis , chemistry , immunology , biochemistry , inflammation , gene , genetics , antibiotics
Pyroptosis is a process in which a programmed cell death occurs via caspase‐1‐dependent mechanism which is triggered by various pathological stimuli. Streptococcus pneumoniae is a widely known pathogen that causes a variety of serious diseases. However, whether Streptococcus pneumoniae (D39)‐induced pyroptosis remains unclear. We therefore examined the pyroptotic effect of S. pneumoniae on mouse microglial cell line, BV‐2 cells. D39 infected BV‐2 cells clearly showed the expression of active caspase‐1 and IL‐18 was elevated by using western blot analysis. Additionally, the level of IL‐1β was elevated with increasing MOI (1:25, 1:50 and 1:100) of D39 in a concentration‐dependent manner. Moreover, immunoblot analysis indicated that the supernatants of BV‐2 cells treated with D39 contained higher expression of active form of caspase‐1, IL‐18 and IL‐1β, while a decreased level of inactive IL‐1β in the lysates of D39 infected BV‐2 cells was observed, compared with uninfected group. We also found that mRNA expression of IL‐1β rose with increasing MOI of D39. D39 infected BV‐2 cells underwent pyroptosis which had been clarified with an increased level of LDH release from the infected cells. The levels of active caspase‐1, IL‐18 and IL‐1β in D39 infected BV‐2 microglial cells were decreased in the presence of 50 mM of potassium chloride, compared with untreated control, indicating that S. pneumoniae ‐induced pyroptosis is inhibited by blocking potassium efflux. Collectively, our data suggest that S. pneumoniae induces pyroptosis in microglial cells.