Qing-Xian Chang1, Xia Chen2, Nai-Liang Zang3, Le-Qian Li1, Nanbert Zhong4, Lai-Xin Xia5, Qi-Tao Huang6, Mei Zhong7. 1. Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China; First School of Clinical Medicine, Southern Medical University, Guangzhou, China. 2. Department of Obstetrics and Gynecology, Foshan No.1 People Hospital, Foshan, Guangdong, China. 3. First School of Clinical Medicine, Southern Medical University, Guangzhou, China. 4. Department of Human Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA. 5. Department of Developmental Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. 6. Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China; Department of Obstetrics and Gynecology, Foshan Maternal and Fetal Care Hospital, Foshan, Guangdong, China. Electronic address: 15920454515@163.com. 7. Department of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Abstract
BACKGROUNDS: Preeclampsia (PE) is characterized as placental vascular disturbance and excessive secretion of soluble fms-like tyrosine kinase 1 (sFlt-1) into the maternal circulation. Trimethylamine N-oxide (TMAO, a gut microbe-derived metabolite) is strongly associated with various cardiovascular and cerebrovascular diseases. Recently, we observe that higher maternal circulating TMAO and sFlt-1 in patients with PE. The aims of the present study are to explore the effects of TMAO on placental sFlt-1 production and the underlying mechanism in human placenta. METHODS: Human placental explants, human placental primary trophoblasts and the extravillous trophoblasts (EVT) cell line (HRT-8/SVneo) were exposured to various concentrations of TMAO (100, 150, 300, and 600 μM). The mRNA expression and protein secretion of sFlt-1 in placental explants, primary trophoblasts and HRT-8/SVneo cells were determined with qPCR and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production in primary trophoblasts and HRT-8/SVneo cells were measured by peroxide-sensitive fluorescent probe dichlorofluorescein diacetate. RESULTS: Exposure of placental explants, primary trophoblasts and HRT-8/SVneo cells to TMAO significantly enhanced sFlt-1 at both mRNA and protein levels in a dose dependent manner. Moreover, inhibition of NADPH oxidase with apocynin significantly attenuated TMAO-induced ROS production in primary trophoblasts and HRT-8/SVneo, and suppressed sFlt-1 secretion in placental explants, primary trophoblasts and HRT-8/SVneo. CONCLUSIONS: Our findings indicated the NADPH oxidase dependent ROS pathway played a critical role in mediating TMAO-induced sFlt-1 generation in human placenta. TMAO may become a potential novel target for pharmacological or dietary interventions to reduce the risk of developing PE.
BACKGROUNDS: Preeclampsia (PE) is characterized as placental vascular disturbance and excessive secretion of soluble fms-like tyrosine kinase 1 (sFlt-1) into the maternal circulation. Trimethylamine N-oxide (TMAO, a gut microbe-derived metabolite) is strongly associated with various cardiovascular and cerebrovascular diseases. Recently, we observe that higher maternal circulating TMAO and sFlt-1 in patients with PE. The aims of the present study are to explore the effects of TMAO on placental sFlt-1 production and the underlying mechanism in human placenta. METHODS: Human placental explants, human placental primary trophoblasts and the extravillous trophoblasts (EVT) cell line (HRT-8/SVneo) were exposured to various concentrations of TMAO (100, 150, 300, and 600 μM). The mRNA expression and protein secretion of sFlt-1 in placental explants, primary trophoblasts and HRT-8/SVneo cells were determined with qPCR and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production in primary trophoblasts and HRT-8/SVneo cells were measured by peroxide-sensitive fluorescent probe dichlorofluorescein diacetate. RESULTS: Exposure of placental explants, primary trophoblasts and HRT-8/SVneo cells to TMAO significantly enhanced sFlt-1 at both mRNA and protein levels in a dose dependent manner. Moreover, inhibition of NADPH oxidase with apocynin significantly attenuated TMAO-induced ROS production in primary trophoblasts and HRT-8/SVneo, and suppressed sFlt-1 secretion in placental explants, primary trophoblasts and HRT-8/SVneo. CONCLUSIONS: Our findings indicated the NADPH oxidase dependent ROS pathway played a critical role in mediating TMAO-induced sFlt-1 generation in human placenta. TMAO may become a potential novel target for pharmacological or dietary interventions to reduce the risk of developing PE.