Prenatal one-carbon metabolism dysregulation programs schizophrenia-like deficits.

The methionine-folate cycle-dependent one-carbon metabolism is implicated in the pathophysiology of schizophrenia. Since schizophrenia is a developmental disorder, we examined the effects that perturbation of the one-carbon metabolism during gestation has on mice progeny. Pregnant mice were administered methionine equivalent to double their daily intake during the last week of gestation. Their progeny (MET mice) exhibited schizophrenia-like social deficits, cognitive impairments and elevated stereotypy, decreased neurogenesis and synaptic plasticity, and abnormally reduced local excitatory synaptic connections in CA1 neurons. Neural transcript expression of only one gene, encoding the Npas4 transcription factor, was >twofold altered (downregulated) in MET mice; strikingly, similar Npas4 downregulation occurred in the prefrontal cortex of human patients with schizophrenia. Finally, therapeutic actions of typical (haloperidol) and atypical (clozapine) antipsychotics in MET mice mimicked effects in human schizophrenia patients. Our data support the validity of MET mice as a model for schizophrenia, and uncover methionine metabolism as a potential preventive and/or therapeutic target.

HPLC-DAD and HPLC-ESI-MS analyses of Tiliae flos and its preparations.

In the present study extensive HPLC-DAD, HPLC-ESI-MS and NMR analyses were undertaken in the aqueous preparations (decoctions, infusions) and tinctures of Tilia platyphyllos Scop inflorescences. The aim of this work was to examine in depth the qualitative and quantitative profile of the investigated preparations, which find until today wide applications in pharmaceutical and cosmetic industry, and to propose a validated method for their quality control. An HPLC-DAD-ESI-MS method was developed and optimised for the quantitative determination of the constituents. Marker constituents of Tiliae flos are the flavonoids, while the volatile content is also used for the quality control. However, the analyses of the non-volatile fraction gave complex chromatographic fingerprints containing simple phenolics and low molecular weight procyanidins. The use of different HPLC columns permitted a good separation of the constituents and enabled their quantitation, while HPLC-MS analyses permitted the detection of procyanidin oligomers. Overall, 31 constituents were detected and identified. Extensive preparative chromatographic investigations and 2D-NMR analyses allowed the characterisation of procyanidins as epicatechin derivatives. Finally, the HPLC method was validated and complied with ICH guidelines. This is the first report of detailed analysis of the chemical composition of Tiliae flos.

The NQO1 polymorphism C609T (Pro187Ser) and cancer susceptibility: a comprehensive meta-analysis.

BACKGROUND: Evidence is increasingly emerging about multiple roles for the NAD(P)H quinone oxidoreductase 1 enzyme in cancer. The C609T (rs1800566, Pro187Ser) null polymorphism of the NQO1 gene contributes significantly to the variation in enzymatic activity across different populations. NQO1 C609T polymorphism was thoroughly investigated with respect to cancer susceptibility. The results were inconsistent partly due to low sample sizes. The aim of the present work was to perform a meta-analysis to assess association for all common cancer sites separately and in combination. METHODS: Our meta-analysis involved 92 studies including 21,178 cases and 25,157 controls. Statistical analysis involved individual cancer sites and the combined cancer risk. Association was tested under different genetic models. RESULTS: We found a statistically significant association between the variant T allele and overall cancer risk in the worldwide population (for the TT vs CC model, OR=1.18 (1.07-1.31), P=0.002, I²=36%). Stratified analysis revealed that this association was largely attributed to the Caucasian ethnicity (for the TT vs CC model, OR=1.28 (1.12-1.46), P=0.0002, I²=1%). Stratification by tumour site showed significant association for bladder cancer in the worldwide population (for the TT vs CC model, OR=1.70 (1.17-2.46), P=0.005, I²=0%), and in the Asian population (for the TT vs CC model, 1.48 (1.14-1.93), P=0.003, I²=16%). Positive association was also found for gastric cancer in the worldwide population under the dominant model (OR=1.34 (1.09-1.65), P=0.006, I²=15%). CONCLUSION: Our results indicate that the C609T polymorphism of the NQO1 gene is an important genetic risk factor in cancer.

An EJC factor RBM8a regulates anxiety behaviors.

Neuroplasticity depends on the precise timing of gene expression, which requires accurate control of mRNA stability and rapid elimination of abnormal mRNA. Nonsense-mediated mRNA decay (NMD) is an RNA surveillance mechanism that ensures the speedy degradation of mRNAs carrying premature termination codons (PTCs). This mechanism relies on several key Exon Junction Complex (EJC) factors to distinguish PTCs from normal stop codons. NMD degrades not only aberrant transcripts carrying PTCs, but also normal transcripts harboring a normal stop codon [1]. Intriguingly, mutations in an NMD factor, Upf3b, have been found in patients with autism [2, 3]. A binding partner of Upf3b, RBM8a, is located in the 1q21.1 copy-number variation (CNV) associated with mental retardation, autism [4], schizophrenia [5], and microcephaly [6]. However, the functions of EJC factors and their roles in behavioral regulation are still elusive. RBM8a protein is a core component of the EJC that plays an important role in NMD. Recent genetic study indicated that RBM8a gain-of-function significantly associated with intellectual disability [7]. In this study we investigated the effect of RBM8a overexpression on affective behaviors in mice. Lentivirus expressing RBM8a was infused into the hippocampus of adult mice to conduct behavioral studies including social interaction, open field, elevated plus maze, and forced swimming tests. Our results showed that overexpression of RBM8a in the mouse dentate gyrus (DG) leads to increased anxiety-like behavior, abnormal social interaction and decreased immobile time in forced swimming test (FST). To examine the underlying mechanism, we found that overexpressing RBM8a in cultured primary neurons lead to significant higher frequency of miniature excitatory postsynaptic currents (mEPSCs). To explore the underlying mechanism of RBM8a mediated behavioral changes, RNA-immunoprecipitation (RNA-IP) detected that RBM8a binds to CaMK2, GluR1 and Egr1 mRNA, suggesting that RBM8a may target neuronal genes to regulate behaviors. This is the first study that demonstrates the key role of RBM8a on the emotional behaviors in mice. These results reveal new neural mechanisms by which NMD modulates behaviors and potentially provide a better understanding of pathophysiology underlying psychiatric disorders.

Duplex Detection of TP53 Arg72Pro and 16 bp Del/Ins Polymorphisms by a Simple Optimized PCR-RFLP Method.

BACKGROUND: The tumor suppressor gene (TP53) encodes p53, the central protein in the apoptotic pathway which has been shown to be of crucial importance in the development of cancers in addition to a variety of neurodegenerative disorders. Two most commonly studied polymorphisms that were shown to affect the biochemical functions of p53 protein are the exon 4 Arg72pro and Intron 3 16 bp Del/Ins polymorphisms. AIMS: The aim of the present work is to develop a new optimized method for the simultaneous detection of the two important polymorphisms in the TP53 gene in a single reaction. MATERIALS AND METHODS: The proposed method is based on amplification of a single PCR amplicon and the use of a unique restriction enzyme with restriction sites that facilitate simultaneous detection. RESULTS: The proposed method offers fast, economical, and simple simultaneous detection. Validation by methods commonly used in the literature showed perferct concordance in genotyping results. CONCLUSION: The proposed method can serve as an invaluable tool for the investigation of TP53 Arg72Pro-16 bp Del/Ins haplotype, and the combined effects of the two polymorphisms offering extreme ease and simplicity over the currently used methods which are based on two separate detections.