Disruption of Planar Cell Polarity Pathway Attributable to Valproic Acid-Induced Congenital Heart Disease through Hdac3 Participation in Mice.

BACKGROUND: Valproic acid (VPA) exposure during pregnancy has been proven to contribute to congenital heart disease (CHD). Our previous findings implied that disruption of planar cell polarity (PCP) signaling pathway in cardiomyocytes might be a factor for the cardiac teratogenesis of VPA. In addition, the teratogenic ability of VPA is positively correlated to its histone deacetylase (HDAC) inhibition activity. This study aimed to investigate the effect of the VPA on cardiac morphogenesis, HDAC1/2/3, and PCP key genes (Vangl2/Scrib/Rac1), subsequently screening out the specific HDACs regulating PCP pathway. METHODS: VPA was administered to pregnant C57BL mice at 700 mg/kg intraperitoneally on embryonic day 10.5. Dams were sacrificed on E15.5, and death/absorption rates of embryos were evaluated. Embryonic hearts were observed by hematoxylin-eosin staining to identify cardiac abnormalities. H9C2 cells (undifferentiated rat cardiomyoblasts) were transfected with Hdac1/2/3 specific small interfering RNA (siRNA). Based on the results of siRNA transfection, cells were transfected with Hdac3 expression plasmid and subsequently mock-treated or treated with 8.0 mmol/L VPA. Hdac1/2/3 as well as Vangl2/Scrib/Rac1 mRNA and protein levels were determined by real-time quantitative polymerase chain reaction and Western blotting, respectively. Total HDAC activity was detected by colorimetric assay. RESULTS: VPA could induce CHD (P < 0.001) and inhibit mRNA or protein expression of Hdac1/2/3 as well as Vangl2/Scrib in fetal hearts, in association with total Hdac activity repression (all P < 0.05). In vitro, Hdac3 inhibition could significantly decrease Vangl2/Scrib expression (P < 0.01), while knockdown of Hdac1/2 had no influence (P > 0.05); VPA exposure dramatically decreased the expression of Vanlg2/Scrib together with Hdac activity (P < 0.01), while overexpression of Hdac3 could rescue the VPA-induced inhibition (P > 0.05). CONCLUSION: VPA could inhibit Hdac1/2/3, Vangl2/Scrib, or total Hdac activity both in vitro and in vivo and Hdac3 might participate in the process of VPA-induced cardiac developmental anomalies.

Effect of Histone Deacetylase Inhibition on the Expression of Multidrug Resistance-associated Protein 2 in a Human Placental Trophoblast Cell Line.

BACKGROUND: Placental multidrug resistance-associated protein 2 (MRP2), encoded by ABCC2 gene in human, plays a significant role in regulating drugs' transplacental transfer rates. Studies on placental MRP2 regulation could provide more therapeutic targets for individualized and safe pharmacotherapy during pregnancy. Currently, the roles of epigenetic mechanisms in regulating placental drug transporters are still unclear. This study aimed to investigate the effect of histone deacetylases (HDACs) inhibition on MRP2 expression in the placental trophoblast cell line and to explore whether HDAC1/2/3 are preliminarily involved in this process. METHODS: The human choriocarcinoma-derived trophoblast cell line (Bewo cells) was treated with the HDAC inhibitors-trichostatin A (TSA) at different concentration gradients of 0.5, 1.0, 3.0, and 5.0 µmol/L. Cells were harvested after 24 and 48 h treatment. Small interfering RNA (siRNA) specific for HDAC1/HDAC2/HDAC3 or control siRNA was transfected into cells. Total HDAC activity was detected by colorimetric assay kits. HDAC1/2/3/ABCC2 messenger RNA (mRNA) and protein expressions were determined by real-time quantitative polymerase chain reaction and Western-blot analysis, respectively. Immunofluorescence for MRP2 protein expression was visualized and assessed using an immunofluorescence microscopy and ImageJ software, respectively. RESULTS: TSA could inhibit total HDAC activity and HDAC1/2/3 expression in company with increase of MRP2 expression in Bewo cells. Reduction of HDAC1 protein level was noted after 24 h of TSA incubation at 1.0, 3.0, and 5.0 µmol/L (vs. vehicle group, all P < 0.001), accompanied with dose-dependent induction of MRP2 expression (P = 0.045 for 1.0 µmol/L, P = 0.001 for 3.0 µmol/L, and P < 0.001 for 5.0 µmol/L), whereas no significant differences in MRP2 expression were noted after HDAC2/3 silencing. Fluorescent micrograph images of MRP2 protein were expressed on the cell membrane. The fluorescent intensities of MRP2 in the control, HDAC2, and HDAC3 siRNA-transfected cells were week, and no significant differences were noticed among these three groups (all P > 0.05). However, MRP2 expression was remarkably elevated in HDAC1 siRNA-transfected cells, which displayed an almost 3.19-fold changes in comparison with the control siRNA-transfected cells (P < 0.001). CONCLUSIONS: HDACs inhibition could up-regulate placental MRP2 expression in vitro, and HDAC1 was probably to be involved in this process.

[Effect of histone acetylation/deacetylation imbalances on key gene of planar cell polarity pathway].

OBJECTIVE: To investigate the effect of histone acetylation/deacetylation imbalances on embryonic hearts of mice and its effect on key genes of planar cell polarity (PCP) pathway-Vangl2, Scrib and Rac1 in H9C2 cells. METHODS: Forty pregnant C57/B6 mice were randomly assigned into three groups: blank group (n=10), vehicle group (n=10), and valproic acid (VPA)-treated group (n=20). In the VPA-treated group, VPA, a histone deacetylase (HDAC) inhibitor, was administered to each individual dam intraperitoneally at a single dose of 700 mg/kg on embryonic day 10.5 (E10.5). The vehicle and blank groups received equivalent saline or no interventions, respectively. Dams were sacrificed on E15.5, and death rates of embryos were evaluated. Subsequently, embryonic hearts of survival fetus were removed to observe cardiac abnormalities by hematoxylin-eosin (HE) staining. H9C2 cells were cultured and allotted to the blank, vehicle, and VPA-treated groups: the VPA treated group received VPA exposure at concentrations of 2.0, 4.0 and 8.0 mmol/L; the vehicle and blank groups received equivalent saline or no interventions, respectively. HDAC1-3 as well as Vangl2, Scrib and Rac1 mRNA and protein expression levels were determined by quantitative real-time PCR and Western blot, respectively. The total HDAC activity was analyzed by colorimetric assay. RESULTS: The fetus mortality rate after VPA treatment was 31.7%, with a significantly higher rate of cardiac abnormalities in comparison with the controls (P<0.05). In comparison with the blank and vehicle groups, HDAC1 mRNA was significantly increased at various concentrations of VPA treatment at all time points of exposure (P<0.05), together with a reduction of protein level after 48 and 72 hours of exposure (P<0.05). The inhibition of HDAC2 mRNA after various concentrations of VPA incubation was pronounced at 24 hours of exposure (P<0.05), while the protein levels were reduced at all time points (P<0.05). HDAC3 mRNA was prominently induced by VPA (4.0 and 8.0 mmol/L) at all time points of treatment (P<0.05). In contrast, the protein level was inhibited after VPA treatment (P<0.05). In comparison with the blank and vehicle groups, Vangl2 mRNA as well as Scrib mRNA/protein expression levels were markedly reduced after 48 and 72 hours of VPA treatment (P<0.05), together with a reduction of protein level in Vangl2 at 72 hours (P<0.05). Compared with the blank and vehicle groups, a significant repression in the total HDAC activity was observed in the VPA-treated group at concentrations of 4.0 and 8.0 mmol/L after 24 hours of treatment (P<0.05), and the effect persisted up to 48 and 72 hours, exhibiting pronounced inhibition at all concentrations (P<0.05). CONCLUSIONS: VPA might result in acetylation/deacetylation imbalances by inhibiting HDAC1-3 protein expression and total HDAC activity, leading to the down-regulation of mRNA and protein expression of Vangl2 and Scrib. This could be one of the mechanisms contributing to congenital heart disease.

Chemoselective synthesis of trifluoromethylated γ-butenolide derivatives via phosphine-promoted tandem reaction of allylic carbonates and trifluoromethyl ketones.

A novel chemoselective phosphine-mediated tandem reaction between nonsubstituted MBH carbonates and aryl trifluoromethyl ketones is described. The product selectivity of the reaction is easily tunable by changing the ratios of the two reactants, and mono- or bicyclic bistrifluoromethylated vinyl γ-butenolide products can be prepared with good chemoselectivity in modest-to-good yields and diastereoselectivities. The formation of the bicyclic γ-butenolide structures via a one-pot four-step sequence under phosphine catalysis is unprecedented.