Activation of Krüppel-Like Factor 2 with Ginkgo Biloba Extract Induces eNOS Expression and Increases NO Production in Cultured Human Umbilical Endothelial Cells.
BACKGROUND
The mechanisms responsible for the effects of Ginkgo biloba extract (GbE) are not fully understood. Krüppel-like factor 2 (KLF2), a zinc transcription factor, has vasculoprotective effects if activated. The present study attempted to explore whether GbE may activate KLF2 and its consequences.


METHODS
To determine the effects of GbE on endothelial cells, human umbilical vein endothelial cells (HUVECs) were incubated with various concentrations of GbE. KLF2 expression levels were determined by quantitative reverse transcription polymerase chain reaction. Cytoskeleton staining and cell migration assays were performed to determine the effects of KLF2 activation. Moreover, endothelial NO synthase (eNOS) expression levels were detected by PCR and Western blot testing. Nitric oxide (NO) production was also measured with 4,5-diaminofluorescein. A knockdown of KLF2 was performed to identify the role of KLF2 in GbE-induced eNOS expression and NO production.


RESULTS
HUVECs that were incubated with GbE increased KLF2 expression. These cells demonstrated an altered cell morphology, cytoskeleton rearrangement, and inhibited migration activity. Moreover, eNOS expression and NO production increased in a dose-dependent manner when cells were treated with GbE. Correspondingly, silencing of KLF2 in HUVECs decreased eNOS expression and NO production in GbE-treated cells.


CONCLUSIONS
GbE significantly activated KLF2 expression and KLF2-related endothelial function, including cytoskeleton rearrangement, inhibition of migration, eNOS activation, and NO production. These findings suggest that GbE may induce a vasculoprotective effect in endothelial cells.


BACKGROUND
Endothelial cells; eNOS; Ginkgo biloba extract; KLF2; NO.
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Tsung-Neng
TN
Tsai
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Wei-Shing
WS
Lin
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Chun-Hsien
CH
Wu
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Wen-Yu
WY
Lin
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Kai-Min
KM
Chu
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Cheng-Chung
CC
Cheng
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Chih-Hsueng
CH
Hsu
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Wei-Che
WC
Tsai
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Shu-Meng
SM
Cheng
Division of Cardiology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
Shih-Ping
SP
Yang