PI3K-dependent host cell actin rearrangements are required for Cronobacter sakazakii invasion of human brain microvascular endothelial cells.
Cronobacter sakazakii (C. sakazakii) is an opportunistic pathogen that can cause neonatal sepsis and meningitis. The mechanism involved in the pathogenesis of C. sakazakii meningitis remains largely unknown. Previous studies indicated that bacterial invasion of brain microvascular endothelial cells is required for penetration into the central nervous system. In this study, we found that C. sakazakii invasion of human brain microvascular endothelial cells (HBMEC) was significantly inhibited by cytochalasin D, a disrupting agent of actin microfilaments. Disassembly of actin stress fibers and cortical actin fibers was observed in HBMEC infected with C. sakazakii. C. sakazakii infection leads to increased Akt phosphorylation in HBMEC, which was blocked by treatment with PI3K inhibitors. Meanwhile, PI3K and Akt inhibitors significantly inhibited C. sakazakii invasion of HBMEC. Our further results illustrated that the C. sakazakii-induced Akt activation and C. sakazakii invasion were attenuated in HBMEC transfected with dominant-negative PI3K (Δp110). More importantly, the actin filaments rearrangements in HBMEC induced by C. sakazakii were effectively blocked by PI3K inhibitors treatment and transfection with Δp110. Taken together, our findings demonstrated that PI3K-mediated actin rearrangements are required for C. sakazakii invasion of HBMEC.
Li
Qiang
Q
Department of Developmental Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Heping District, Shenyang, China.
Zhao
Wei-Dong
WD
Zhang
Ke
K
Fang
Wen-Gang
WG
Hu
Ying
Y
Wu
Shao-Hui
SH
Chen
Yu-Hua
YH
D000199:Actins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000633:toxicity; D042783:Endothelial Cells / Q000382:microbiology*; D004755:Enterobacteriaceae / Q000472:pathogenicity*; D006801:Humans; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation
D000199:Actins; D015638:Cytochalasin D; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors
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