Background Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals characterized by environmental persistence and have been ubiquitously detected in pregnant women. Although existing evidence suggests that PFAS may exert endocrine-disrupting effects, evidence remains limited regarding the associations of individual legacy and emerging PFAS congeners, as well as PFAS mixtures, with fetal hormonal homeostasis. Objective Based on the Jiashan Birth Cohort in China, to investigate the associations between maternal plasma concentrations of legacy and emerging PFAS in the second trimester and levels of multiple hormones in fetal cord blood. Methods A total of 336 women in the second trimester from the Jiashan Birth Cohort were enrolled. Concentrations of 53 legacy and emerging PFAS were measured in maternal plasma, and levels of eight key hormones were determined in fetal cord blood. Multiple linear regression, restricted cubic spline, and Bayesian kernel machine regression models were used to examine the linear, nonlinear, and joint associations of individual PFAS and PFAS mixtures with fetal cord blood hormone levels. Results Maternal plasma concentrations of perfluorononanoic acid, perfluorohexane sulfonic acid, perfluorooctanesulfonic acid, and 8:2 chlorinated perfluoroether sulfonic acid were positively associated with cord blood levels of insulin-like growth factor 1 (IGF1), with β values of 0.040, 0.050, 0.040, and 0.030, respectively (all P<0.05). In contrast, perfluoroheptanoic acid was negatively associated with prolactin levels (β=−0.060, P<0.01). Restricted cubic spline models revealed a nonlinear dose–response relationship between perfluorobutane sulfonic acid and growth hormone (likelihood ratio test P=0.045), with a positive association in the intermediate concentration interval (β=0.261, P=0.010) that turned negative at higher concentrations (β=−0.425, P=0.048), as well as a nonlinear trend between 6:2 fluorotelomer sulfonic acid and prolactin (likelihood ratio test P=0.074). Bayesian kernel machine regression analysis indicated a negative trend between PFAS mixture exposure and cord blood prolactin levels. Conclusion Maternal PFAS exposure in the second trimester is associated with higher insulin-like growth factor 1 levels and lower prolactin levels in fetal cord blood. Prolactin appears to be consistently associated with both individual PFAS congeners and PFAS mixtures. These findings suggest that maternal PFAS exposure may affect fetal endocrine homeostasis by disrupting the hypothalamic-pituitary-prolactin regulatory axis.

Human nerve growth factor (NGF) is a nerve cell growth regulation factor, which can provide nutrition for the neurons and promote the neurites outgrowth. In order to produce large-scale recombinant human nerve growth factor (rh-beta-NGF), we constructed a plasmid vector, which can stably express the rh-beta-NGF in the HEK293 cell lines. First, the plasmid of pCMV-beta-NGF-IRES-dhfr was constructed and transformed into HEK293 cells. Then MTX pressurized filter and limiting dilution methods were used to obtain monoclonal HEK293 cell lines. After stepwise reducing serum in culture media, the cells eventually adapted to serum-free medium and secreted rh-beta-NGF. SDS-PAGE analysis revealed that the expression product owned a molecular weight of about 13 kDa and a purity of more than 50%. The peptide mapping sequencing analysis demonstrated the sequences of rh-beta-NGF matched with the theoretical ones. Later we purified this protein by ion exchange and molecular sieve chromatograph. Finally, our experimental results exhibited that the recombinant cell lines can stably express rh-beta-NGF with a high efficiency of more than 20 pg/cell x day. In addition, this protein could successfully induce differentiation of PC12 cells. In summary, our recombinant HEK293 cells can express bio-active rh-beta-NGF with great efficiency and stability, which supply a valid basis to large-scale production of rh-beta-NGF.
Cell Differentiation ; Genetic Vectors ; HEK293 Cells ; Humans ; Nerve Growth Factor ; biosynthesis ; Plasmids ; Recombinant Proteins ; biosynthesis