Maternal nicotinamide supplementation causes global DNA hypomethylation, uracil hypo-incorporation and gene expression changes in fetal rats.

Recent evidence shows that excess nicotinamide can cause epigenetic changes in developing rats. The aim of the present study was to investigate the effects of maternal nicotinamide supplementation on the fetus. Female rats were randomised into four groups fed a standard chow diet (control group) or diets supplemented with 1 g/kg of nicotinamide (low-dose group), 4 g/kg of nicotinamide (high-dose group) or 4 g/kg of nicotinamide plus 2 g/kg of betaine (betaine group) for 14-16 d before mating and throughout the study. Fetal tissue samples were collected on the 20th day of pregnancy. Compared with the control group, the high-dose group had a higher fetal death rate, and the average fetal body weight was higher in the low-dose group but lower in the high-dose group. Nicotinamide supplementation led to a decrease in placental and fetal hepatic genomic DNA methylation and genomic uracil contents (a factor modifying DNA for diversity) in the placenta and fetal liver and brain, which could be completely or partially prevented by betaine. Moreover, nicotinamide supplementation induced tissue-specific alterations in the mRNA expression of the genes encoding nicotinamide N-methyltransferase, DNA methyltransferase 1, catalase and tumour protein p53 in the placenta and fetal liver. High-dose nicotinamide supplementation increased fetal hepatic α-fetoprotein mRNA level, which was prevented by betaine supplementation. It is concluded that maternal nicotinamide supplementation can induce changes in fetal epigenetic modification and DNA base composition. The present study raises the concern that maternal nicotinamide supplementation may play a role in the development of epigenetic-related diseases in the offspring.

Nicotinamide supplementation induces detrimental metabolic and epigenetic changes in developing rats.

Ecological evidence suggests that niacin (nicotinamide and nicotinic acid) fortification may be involved in the increased prevalence of obesity and type 2 diabetes, both of which are associated with insulin resistance and epigenetic changes. The purpose of the present study was to investigate nicotinamide-induced metabolic changes and their relationship with possible epigenetic changes. Male rats (5 weeks old) were fed with a basal diet (control group) or diets supplemented with 1 or 4 g/kg of nicotinamide for 8 weeks. Low-dose nicotinamide exposure increased weight gain, but high-dose one did not. The nicotinamide-treated rats had higher hepatic and renal levels of 8-hydroxy-2'-deoxyguanosine, a marker of DNA damage, and impaired glucose tolerance and insulin sensitivity when compared with the control rats. Nicotinamide supplementation increased the plasma levels of nicotinamide, N1-methylnicotinamide and choline and decreased the levels of betaine, which is associated with a decrease in global hepatic DNA methylation and uracil content in DNA. Nicotinamide had gene-specific effects on the methylation of CpG sites within the promoters and the expression of hepatic genes tested that are responsible for methyl transfer reactions (nicotinamide N-methyltransferase and DNA methyltransferase 1), for homocysteine metabolism (betaine-homocysteine S-methyltransferase, methionine synthase and cystathionine ß-synthase) and for oxidative defence (catalase and tumour protein p53). It is concluded that nicotinamide-induced oxidative tissue injury, insulin resistance and disturbed methyl metabolism can lead to epigenetic changes. The present study suggests that long-term high nicotinamide intake (e.g. induced by niacin fortification) may be a risk factor for methylation- and insulin resistance-related metabolic abnormalities.

Excess nicotinamide increases plasma serotonin and histamine levels.

Methylation, a methyl group-consuming reaction, plays a key role in the degradation (i.e., inactivation) of monoamine neurotransmitters, including catecholamines, serotonin and histamine. Without labile methyl groups, the methylation-mediated degradation cannot take place. Although high niacin (nicotinic acid and nicotinamide) intake, which is very common nowadays, is known to deplete the body's methyl-group pool, its effect on monoamine-neurotransmitter degradation is not well understood. The aim of this article was to investigate the effect of excess nicotinamide on the levels of plasma serotonin and histamine in healthy subjects. Urine and venous blood samples were collected from nine healthy male volunteers before and after oral loading with 100 mg nicotinamide. Plasma N(1)-methylnicotinamide, urinary N(1)-methyl-2-pyridone-5-carboxamide (2-Py), and plasma betaine levels were measured by using high-performance liquid chromatography (HPLC). Plasma concentrations of choline, serotonin and histamine were measured using commercial kits. The results showed that the plasma N(1)-methylnicotinamide level and the urinary excretion of 2-Py significantly increased after oral loading with 100 mg nicotinamide, which was accompanied with a decrease in the methyl-group donor betaine. Compared with those before nicotinamide load, five-hour postload plasma serotonin and histamine levels significantly increased. These results suggest that excess nicotinamide can disturb monoamine-neurotransmitter metabolism. These findings may be of significance in understanding the etiology of monoamine-related mental diseases, such as schizophrenia and autism (a neurodevelopmental disorder).

[The Study of PI3K-â ¢ Like Functional Polypeptide on Leukemia Cell K562 during the Process of Programmed Cell Death].

OBJECTIVE: To study the molecular mechanism of PI3K-Ⅲ like functional domain inducing programmed cell death of leukemia cell line K562. METHODS: The purified PI3K-Ⅲ like functional domain protein was obtained by Pichia pastoris expression system. MTT assay and colony-forming assay were used to detect the effects of PI3K-Ⅲ like functional domain protein on K562 cell proliferation. The effects of PI3K-Ⅲ like functional domain protein on apoptosis and cell cycle of on K562 cells were detected by flow cytometry. The ultrastructural changes were detected by transmission electron microscopy. The expression of caspase-3 was detected by ELISA. The protein expressions of ATG4B, Beclin-1, Bcl-2 and LC3-II were evaluated by Western blot. RESULTS: PI3K-Ⅲ like functional domain protein could inhibit the proliferation and clony formation of K562 cells, which was significantly higher than the control group (P<0.05). In the experimental group, apoptosis and autophagosome were shown in K562 cells. The proportion of cells in G0/G1 phase increased significantly, while in S phase decreased significantly. Cell growth mostly stagnated in G0/G1 phase, which was significantly different from the control group (P<0.05). With the increase of concentration, the expression of caspase-3 protein increased significantly compared with the control group (r=0.966, P<0.05). The expression of ATG4B and beclin-1 appeared from increase to decrease, LC3-II increased while Bcl-2 decreased at different time points. CONCLUSION: PI3K-Ⅲ like functional polypeptide could induce programmed cell death of leukemia cell K562. Beclin-1/Bcl-2 and caspase pathway may be involved in this way, which suggesting meant autophagy and apoptosis may work together at the same time.

Cloning, expression and identification by immunohistochemistry of humanized single-chain variable fragment antibody against hepatitis C virus core protein.

Expression of single-chain variable fragment (scFv) antibodies on the surface of bacteriophage is widely used to prepare antibodies with pre-defined specificities. A phage antibody library containing the gene for scFv antibody against Hepatitis C virus core protein was panned with core protein immobilized on microtiter plate wells. After five rounds of panning 60 phage clones specific to core protein were obtained and one selected clone was sequenced. It was found that the specifically detected antigen consists of 774bp and is capable of encoding 257 amino acids in the patients but not in healthy persons.

The Inhibitory Effects of Recombinant Hespintor Combined with Sorafenib on Transplanted Human Hepatoma in Nude Mice, and Transcriptional Regulation of Hespintor Based on RNA-Seq.

Objective: As targeted drugs, exogenous serpins could be introduced to patients to restore body balance. This study aimed to observe further the inhibitory effects of recombinant Hespintor (a Kazal-type serpin) combined with Sorafenib on transplanted human hepatoma tumors in nude mice specimens and to explore the possible transcriptional regulation by Hespintor. Methods: A model of human hepatoma tumors transplanted in nude mice was established, and the medication was administrated to observe the growth of the tumors. Four weeks after the drug administration, the tumors were removed to evaluate the inhibition effects of Hespintor on in-situ tumor growth and liver metastasis. The expression levels of MMP2, MMP9, Bax, Bcl-2, and caspase-3 in the tumor organizations were detected with Western blot. The target genes of the Hespintor were screened based on tissue RNA-Seq, and the regulatory network was constructed. Results: It was found that the recombinant Hespintor displayed a significant antitumor effect on the subcutaneous growth of MHCC97-H cells. Moreover, the therapeutic effects of the combination therapy were significantly better than those of single therapy. 10 target genes with significantly different expression by Hespintoron tumor tissue were identified. Finally, a visual regulatory networkwas constructed for target mRNA-pathway. Conclusions: The antitumor effect of Hespintor combined with Sorafenib in treating the subcutaneously implanted hepatocellular carcinoma tumors in nude mice was significant. The possible transcriptional regulation by Hespintor involved multiple signaling pathways, and it was not just the antitumor effect of uPA via its extracellular inhibitions.

[Chronic nicotinamide overload and type 2 diabetes].

Type 2 diabetes is a major global health problem. It is generally accepted that type 2 diabetes is the result of gene-environmental interaction. However, the mechanism underlying the interaction is unclear. Diet change is known to play an important role in type 2 diabetes. The fact that the global high prevalence of type 2 diabetes has occurred following the spread of food fortification worldwide suggests a possible involvement of excess niacin intake. Our recent study found that nicotinamide overload and low nicotinamide detoxification may induce oxidative stress associated with insulin resistance. Based on the relevant facts, this review briefly summarized the relationship between the prevalence of type 2 diabetes and the nicotinamide metabolism changes induced by excess niacin intake, aldehyde oxidase inhibitors, liver diseases and functional defects of skin. We speculate that the gene-environmental interaction in type 2 diabetes may be a reflection of the outcome of the association of chronic nicotinamide overload-induced toxicity and the relatively low detoxification/excretion capacity of the body. Reducing the content of niacin in foods may be a promising strategy for the control of type 2 diabetes.

The peptide encoded by a novel putative lncRNA HBVPTPAP inducing the apoptosis of hepatocellular carcinoma cells by modulating JAK/STAT signaling pathways.

When the hepatitis B virus (HBV) enters target cells, there are complex trans-regulatory mechanisms involved in the interactions between the virus and the target cells. In the present study, a new gene screened from the hepatoblastoma cell line HepG2 using suppression subtractive hybridization, referred to as lncRNA HBVPTPAP, was used to study the trans-regulation of HBV DNA polymerase. According to the structural characteristics of the full-length sequences, it was classified as long non-coding RNA. However, a unique and complete open reading frame (ORF) was still present. Therefore, to further identify the lncRNA HBVPTPAP gene's encoding potential, this study used several online tools to analyze and verify its encoding polypeptide authenticity. On that basis, the effects of the lncRNA HBVPTPAP gene on the biological behaviors of HepG2 cells and its molecular regulatory mechanism were investigated. It was found that the lncRNA HBVPTPAP subcellular was mainly located in the cytoplasm, and possibly activated the downstream JAK/STAT signaling pathway through the interaction between the encoding polypeptide and PILRA intracellular domain. Then, the mitochondrial apoptosis pathway may have been initiated to induce apoptosis. These results provided a basis for further study of the biological functions of the lncRNA HBVPTPAP gene.

[Function of TTG1A in hepatic stellate cells].

OBJECTIVE: To investigate the biological functions of TTG1A in liver fibrosis. METHODS: Yeast two-hybrid system was used to screen proteins associated with TTG1A. Briefly, the coding sequence of TTG1A was cloned into pGBKT7 vector, and the recombinant plasmid was transformed into yeast cells AH109 ( a type), then these cells were mated with yeast cells Y187 (a type) transformed with human leukocyte cDNA library plasmid pACT2. The obtained diploid yeast cells were plated on synthetic dropout nutrient medium containing X-alpha-gal for double selection. The plasmids from positive colonies were transformed into E.coli and sequenced. RESULTS: The recombinant yeast expression vector pGBKT7-TTG1A was successfully constructed. Nineteen TTG1A binding proteins, including Homo sapiens major histocompatibility complex, class II DP beta 1 (HLA-DPb1), Homo sapiens ribosomal protein L30 (RPL30), Homo sapiens nucleophosmin Homo sapiens nucleobindin 2 (NUCB2), Homo sapiens ash2, variant Gaucher disease and variant metachromatic leukodystrophy, MORF4L1, Homo sapiens ubiquitin-conjugating enzyme E2L3 (UBE2L3), APOA1, Homo sapiens lectin, and galectin 1, were identified. CONCLUSIONS: This study may help to elucidate the molecular function of TTG1A.

[Identification of Differentially Expressed Gene Core Genes in Early T-Cell Precursor Acute Lymphoblastic Leukemia and Its Regulatory Network Analysis].

OBJECTIVE: To identify the differentially expressed gene (DEG) core genes in early T-cell precursor acute lymphoblastic leukemia (ETP ALL) and to analyze their interactions with upstream miRNAs, lncRNAs and involved pathways; to clarify the regulatory mechanism of ETP ALL development; and to explore the molecular targets for clinical diagnosis and treatment. METHODS: The DEG of ETP ALL were screened based on the intersection of GEO database and TCGA database. The functional enrichment analysis and interaction analysis were carried out for DEG. Next, MCODE algorithm was used to screen core genes of DEG, and the mirDIP online tool and starBase online tool were utilized to predict upstream miRNA and lncRNA of the core genes. RESULTS: A total of 424 DEG with a high credibility were identified, which were mainly enriched in the biological activity, such as transcriptional regulation, signaling pathway and protein function activation according to GO function, and the KEGG pathway was enriched in hematopoiesis, anoxic stress response, transcriptional misregulation, immunity and other functions, which interrelated each other 7 core genes were identified. Subsequently, 7 miRNAs and 19 lncRNAs were predicted to meet screening criteria. Finally, a lncRNA-miRNA-mRNA-pathway regulatory network was constructed. CONCLUSION: The DEG in ETP ALL has been identified based on data mining methods; the core genes have been gained by co-expression analysis, and their upstream miRNA and lncRNA can be predicted for the early diagnosis of ETP ALL, thus providing a theoretical basis for the early diagnosis and reasonable treatment of ETP ALL, and helping to look for new tumor biomarkers of ETP ALL different from classical T-ALL.