Breastfeeding and overweight/obesity among children and adolescents: a cross-sectional study.

BACKGROUND: Overweight and obesity are major public health crises among children and adolescents and contribute to a significant economic burden. We aimed to investigate the relationship between breastfeeding duration and overweight and obesity in children and adolescents in Qingdao, China in 2017. METHODS: This study conducted a survey with 10,753 students (5370 boys and 5383 girls) aged 6 to 16 years from the Shibei District of Qingdao, China in 2017. Anthropometric measurements were taken by well-trained personnel and self-completed questionnaires were used to collect data from students. A variety of statistical methods were used in this study, including univariate and multivariate analyses, as well as linear and nonlinear regression models. RESULTS: The prevalence of overweight and obesity was 15.45% and 19.76%, respectively. There was a significant negative correlation between breastfeeding duration and BMI in children and adolescents (ß = -0.025, 95% CI: -0.033, -0.005, P < 0.01). Among boys, the BMI in children and adolescences of those who have been breastfed for more than 12 months was significantly lower than that of others whose breastfeeding duration was less than 12 months (ß = -0.440, 95%CI -0.655, -0.224, P < 0.01). Breastfeeding has a particularly positive effect on the prevalence of obesity in boys aged 9 to 11 years (OR = 0.978, 95% CI: 0.958,0.999, P < 0.05). CONCLUSION: Breastfeeding can significantly reduce the prevalence of overweight and obesity among children and adolescents aged 6 to 16 years. Those who were breastfed for more than 12 months had a lower risk of developing overweight and obesity, especially boys between the ages of 9 and 11.

Genomic and Transcriptomic Landscape of Tumor Clonal Evolution in Cholangiocarcinoma.

Cholangiocarcinoma remained a severe threat to human health. Deciphering the genomic and/or transcriptomic profiles of tumor has been proved to be a promising strategy for exploring the mechanism of tumorigenesis and development, which could also provide valuable insights into Cholangiocarcinoma. However, little knowledge has been obtained regarding to how the alteration among different omics levels is connected. Here, using whole exome sequencing and transcriptome sequencing, we performed a thorough evaluation for the landscape of genome and transcriptome in cholangiocarcinoma and illustrate the alteration of tumor on different biological levels. Meanwhile, we also identified the clonal structure of each included tumor sample and discovered different clonal evolution patterns related to patients' survival. Furthermore, we extracted subnetworks that were greatly influenced by tumor clonal/subclonal mutations or transcriptome change. The topology relationship between genes affected by genomic/transcriptomic changes in biological interaction networks revealed that alteration of genome and transcriptome was highly correlated, and somatic mutations located on important genes might affect the expression of numerous genes in close range.

MEIS2C and MEIS2D promote tumor progression via Wnt/ß-catenin and hippo/YAP signaling in hepatocellular carcinoma.

BACKGROUND: MEIS2 has been identified as one of the key transcription factors in the gene regulatory network in the development and pathogenesis of human cancers. Our study aims to identify the regulatory mechanisms of MEIS2 in hepatocellular carcinoma (HCC), which could be targeted to develop new therapeutic strategies. METHODS: The variation of MEIS2 levels were assayed in a cohort of HCC patients. The proliferation, clone-formation, migration, and invasion abilities of HCC cells were measured to analyze the effects of MEIS2C and MEIS2D (MEIS2C/D) knockdown with small hairpin RNAs in vitro and in vivo. Chromatin immunoprecipitation (ChIP) was performed to identify MEIS2 binding site. Immunoprecipitation and immunofluorescence assays were employed to detect proteins regulated by MEIS2. RESULTS: The expression of MEIS2C/D was increased in the HCC specimens when compared with the adjacent noncancerous liver (ANL) tissues. Moreover, MEIS2C/D expression negatively correlated with the prognosis of HCC patients. On the other hand, knockdown of MEIS2C/D could inhibit proliferation and diminish migration and invasion of hepatoma cells in vitro and in vivo. Mechanistically, MESI2C activated Wnt/ß-catenin pathway in cooperation with Parafibromin (CDC73), while MEIS2D suppressed Hippo pathway by promoting YAP nuclear translocation via miR-1307-3p/LATS1 axis. Notably, CDC73 could directly either interact with MEIS2C/ß-catenin or MEIS2D/YAP complex, depending on its tyrosine-phosphorylation status. CONCLUSIONS: Our studies indicate that MEISC/D promote HCC development via Wnt/ß-catenin and Hippo/YAP signaling pathways, highlighting the complex molecular network of MEIS2C/D in HCC pathogenesis. These results suggest that MEISC/D may serve as a potential novel therapeutic target for HCC.

Differential m6A, m6Am, and m1A Demethylation Mediated by FTO in the Cell Nucleus and Cytoplasm.

FTO, the first RNA demethylase discovered, mediates the demethylation of internal N6-methyladenosine (m6A) and N6, 2-O-dimethyladenosine (m6Am) at the +1 position from the 5' cap in mRNA. Here we demonstrate that the cellular distribution of FTO is distinct among different cell lines, affecting the access of FTO to different RNA substrates. We find that FTO binds multiple RNA species, including mRNA, snRNA, and tRNA, and can demethylate internal m6A and cap m6Am in mRNA, internal m6A in U6 RNA, internal and cap m6Am in snRNAs, and N1-methyladenosine (m1A) in tRNA. FTO-mediated demethylation has a greater effect on the transcript levels of mRNAs possessing internal m6A than the ones with cap m6Am in the tested cells. We also show that FTO can directly repress translation by catalyzing m1A tRNA demethylation. Collectively, FTO-mediated RNA demethylation occurs to m6A and m6Am in mRNA and snRNA as well as m1A in tRNA.

Adapting to oxygen: 3-Hydroxyanthrinilate 3,4-dioxygenase employs loop dynamics to accommodate two substrates with disparate polarities.

3-Hydroxyanthranilate 3,4-dioxygenase (HAO) is an iron-dependent protein that activates O2 and inserts both oxygen atoms into 3-hydroxyanthranilate (3-HAA). An intriguing question is how HAO can rapidly bind O2, even though local O2 concentrations and diffusion rates are relatively low. Here, a close inspection of the HAO structures revealed that substrate- and inhibitor-bound structures exhibit a closed conformation with three hydrophobic loop regions moving toward the catalytic iron center, whereas the ligand-free structure is open. We hypothesized that these loop movements enhance O2 binding to the binary complex of HAO and 3-HAA. We found that the carboxyl end of 3-HAA triggers changes in two loop regions and that the third loop movement appears to be driven by an H-bond interaction between Asn27 and Ile142 Mutational analyses revealed that N27A, I142A, and I142P variants cannot form a closed conformation, and steady-state kinetic assays indicated that these variants have a substantially higher Km for O2 than WT HAO. This observation suggested enhanced hydrophobicity at the iron center resulting from the concerted loop movements after the binding of the primary substrate, which is hydrophilic. Given that O2 is nonpolar, the increased hydrophobicity at the iron center of the binary complex appears to be essential for rapid O2 binding and activation, explaining the reason for the 3-HAA-induced loop movements. Because substrate binding-induced open-to-closed conformational changes are common, the results reported here may help further our understanding of how oxygen is enriched in nonheme iron-dependent dioxygenases.

Identifying key regulating miRNAs in hepatocellular carcinomas by an omics' method.

The miRNAs play important regulating roles in the pathogenesis of hepatocellular carcinoma (HCC). To uncover key regulating miRNAs in HCC that were neglected by traditional analyzing methods of transcriptomics data, we proposed a novel molecular-network-based omics' (MNBO) method. With this method, we predicted HCC-regulating miRNAs, and confirmed the role of a novel miR-590-3P/EED axis by a clinical study and in vitro, in vivo wet-experiments. The miR-590-3P is significantly down-regulated in HCC patients. And low level of miR-590-3P in HCC is associated with poor prognosis of patients. In HCC cell lines, the miR-590-3P suppressed cell proliferation by inhibiting the transformation G1 phase to S phases of the cell cycle. Moreover, the miR-590-3P inhibited migration and invasion of HCC cells. Further investigations indicated that miR-590-3P play its roles by inhibiting polycomb protein EED. The experiments in animal model implied miR-590-3P could be a potential therapeutic agent for HCC in the future. In conclusion, the discovery of miR-590-3P revealed the MNBO would be a useful strategy to uncover key regulating miRNAs in HCC.

A new modification for mammalian messenger RNA.

The discovery of multiple RNA modifications in the past few years has broadened our views of the structures and potential functions of RNA species, but deciphering which modifications are made where and how remains a challenge. A new study by Xu et al. applies a combination of mass spectrometry, biochemistry, genetics, and cellular biology tools to reveal the two mammalian methyltransferases that are responsible for m3C installation in tRNA and a third that mediates the previously unknown installation of m3C in mammalian mRNA.

Melatonin prevents sleep deprivation-associated anxiety-like behavior in rats: role of oxidative stress and balance between GABAergic and glutamatergic transmission.

Sleep deprivation (SD) has been shown to induce anxiety-like behavior. Melatonin, an endogenous potent antioxidant, protects neurons from oxidative stress in many disease models. Here we investigated the effect of melatonin against SD-induced anxiety-like behavior and attempted to define the possible mechanisms involved. SD was induced in rats using modified multiple platform model. Melatonin (15 mg/kg) was administered to the rats via intraperitoneal injection. The elevated plus maze test, open field test and light-dark exploration were used to evaluate anxiety-like behavior. Serum corticosterone was measured to determine stress level. Malondialdehyde (MDA) level and superoxide dismutase (SOD) enzyme activity of amygdala and serum were performed to determine the level of oxidative stress. Levels of protein were detected by means of Western blot. The results showed that SD induces anxiety-like behavior, while melatonin treatment prevented these changes. Serum corticosterone also increased with SD but its levels were normalized by melatonin. In addition, melatonin reversed SD-induced changes in MDA and SOD in both of amygdala and serum. The results of Western blot showed that melatonin attenuated the up-regulation of NR2B-containing N-methyl-D-aspartate receptors, GluR1 subunit of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor as well as phosphorylation of GluR1 at Ser831, and Ca2+/calmodulin-dependent protein kinase II-alpha in SD rats. Meanwhile, melatonin blocked the down-regulation of γ-aminobutyric acid A-alpha-2 receptor. In conclusion, our results suggest that melatonin prevents anxiety-like behavior induced by SD. The possible mechanism may be attributed to its ability to reduce oxidative stress and maintain balance between GABAergic and glutamatergic transmission.

Hypertryptophanemia due to tryptophan 2,3-dioxygenase deficiency.

In this report we describe the first human case of hypertryptophanemia confirmed to be due to tryptophan 2,3-dioxygenase deficiency. The underlying etiology was established by sequencing the TDO2 gene, in which there was compound heterozygosity for two rare variants: c.324G>C, p.Met108Ile and c.491dup, p.Ile165Aspfs*12. The pathogenicity of these variants was confirmed by molecular-level studies, which showed that c.491dup does not produce soluble protein and c.324G>C results in a catalytically less efficient Met108Ile enzyme that is prone to proteolytic degradation. The biochemical phenotype of hypertryptophanemia and hyperserotoninemia does not appear to have significant clinical consequences.

Investigation on maternal lineage of a Neolithic group from northern Shaanxi based on ancient DNA.

A magnetic bead purification method was successfully used to extract ancient DNA from the skeletal remains of 10 specimens excavated from Wuzhuangguoliang (Wzhgl) site, which was located in northern Shaanxi. The multidimensional scaling (MDS) and analysis of molecular variance approach (AMOVA) revealed that ancient Wzhgl people bored a very high similarity to southern Han Chinese. By constructing the MJ-network of various modern people including Han Chinese and Japanese, the phylogenetic analysis indicated that the Wzhgl population had close maternal distance with ancient Shandong and Xinjiang people. These findings indicated that Wzhgl contributed to the gene pool of Han Chinese and modern Japanese. In addition, population migration and interflow between Wzhgl people and ancient Shandong or Xinjiang probably occurred in Neolithic period.

ALKBH1-Mediated tRNA Demethylation Regulates Translation.

tRNA is a central component of protein synthesis and the cell signaling network. One salient feature of tRNA is its heavily modified status, which can critically impact its function. Here, we show that mammalian ALKBH1 is a tRNA demethylase. It mediates the demethylation of N1-methyladenosine (m1A) in tRNAs. The ALKBH1-catalyzed demethylation of the target tRNAs results in attenuated translation initiation and decreased usage of tRNAs in protein synthesis. This process is dynamic and responds to glucose availability to affect translation. Our results uncover reversible methylation of tRNA as a new mechanism of post-transcriptional gene expression regulation.

CTNNA3 is a tumor suppressor in hepatocellular carcinomas and is inhibited by miR-425.

Hepatocellular carcinoma (HCC) is a common and leading cause of death worldwide. Here, we identified that a cell-cell adhesion gene, CTNNA3, is a tumor suppressor in HCC. CTNNA3 inhibited the proliferation, migration and invasion of HCC cell lines. In these cells, CTNNA3 inhibited Akt signal, and in turn decreased the proliferating cell nuclear antigen (PCNA) and the matrix metallopeptidase MMP-9, and increased the cell cycle inhibitor p21(Cip1/Waf1). Meanwhile, CTNNA3 is inhibited by miR-425 in HCC. The miR-425 directly bound to the 3'UTR of CTNNA3 and inhibited its expression. The tumor suppressor function of CTNNA3 and the oncogenic function of miR-425 were further confirmed in HCC cell xenograft in nude mice. The miR-425/CTNNA3 axis may provide insights into the mechanisms underlying HCC, and contribute to potential therapeutic strategy of HCC.

An Iron Reservoir to the Catalytic Metal: THE RUBREDOXIN IRON IN AN EXTRADIOL DIOXYGENASE.

The rubredoxin motif is present in over 74,000 protein sequences and 2,000 structures, but few have known functions. A secondary, non-catalytic, rubredoxin-like iron site is conserved in 3-hydroxyanthranilate 3,4-dioxygenase (HAO), from single cellular sources but not multicellular sources. Through the population of the two metal binding sites with various metals in bacterial HAO, the structural and functional relationship of the rubredoxin-like site was investigated using kinetic, spectroscopic, crystallographic, and computational approaches. It is shown that the first metal presented preferentially binds to the catalytic site rather than the rubredoxin-like site, which selectively binds iron when the catalytic site is occupied. Furthermore, an iron ion bound to the rubredoxin-like site is readily delivered to an empty catalytic site of metal-free HAO via an intermolecular transfer mechanism. Through the use of metal analysis and catalytic activity measurements, we show that a downstream metabolic intermediate can selectively remove the catalytic iron. As the prokaryotic HAO is often crucial for cell survival, there is a need for ensuring its activity. These results suggest that the rubredoxin-like site is a possible auxiliary iron source to the catalytic center when it is lost during catalysis in a pathway with metabolic intermediates of metal-chelating properties. A spare tire concept is proposed based on this biochemical study, and this concept opens up a potentially new functional paradigm for iron-sulfur centers in iron-dependent enzymes as transient iron binding and shuttling sites to ensure full metal loading of the catalytic site.

Magnolol administration in normotensive young spontaneously hypertensive rats postpones the development of hypertension: role of increased PPAR gamma, reduced TRB3 and resultant alleviative vascular insulin resistance.

Patients with prehypertension are more likely to progress to manifest hypertension than those with optimal or normal blood pressure. However, the mechanisms underlying the development from prehypertension to hypertension still remain largely elusive and the drugs for antihypertensive treatment in prehypertension are absent. Here we determined the effects of magnolol (MAG) on blood pressure and aortic vasodilatation to insulin, and investigated the underlying mechanisms. Four-week-old male spontaneous hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) control rats were used. Our results shown that treatment of young SHRs with MAG (100 mg/kg/day, o.g.) for 3 weeks decreased blood pressure, improved insulin-induced aorta vasodilation, restored Akt and eNOS activation stimulated by insulin, and increased PPARγ and decreased TRB3 expressions. In cultured human umbilical vein endothelial cells (HUVECs), MAG incubation increased PPARγ, decreased TRB3 expressions, and restored insulin-induced phosphorylated Akt and eNOS levels and NO production, which was blocked by both PPARγ antagonist and siRNA targeting PPARγ. Improved insulin signaling in HUVECs by MAG was abolished by upregulating TRB3 expression. In conclusion, treatment of young SHRs with MAG beginning at the prehypertensive stage decreases blood pressure via improving vascular insulin resistance that is at least partly attributable to upregulated PPARγ, downregulated TRB3 and consequently increased Akt and eNOS activations in blood vessels in SHRs.

Crystallographic and spectroscopic snapshots reveal a dehydrogenase in action.

Aldehydes are ubiquitous intermediates in metabolic pathways and their innate reactivity can often make them quite unstable. There are several aldehydic intermediates in the metabolic pathway for tryptophan degradation that can decay into neuroactive compounds that have been associated with numerous neurological diseases. An enzyme of this pathway, 2-aminomuconate-6-semialdehyde dehydrogenase, is responsible for 'disarming' the final aldehydic intermediate. Here we show the crystal structures of a bacterial analogue enzyme in five catalytically relevant forms: resting state, one binary and two ternary complexes, and a covalent, thioacyl intermediate. We also report the crystal structures of a tetrahedral, thiohemiacetal intermediate, a thioacyl intermediate and an NAD(+)-bound complex from an active site mutant. These covalent intermediates are characterized by single-crystal and solution-state electronic absorption spectroscopy. The crystal structures reveal that the substrate undergoes an E/Z isomerization at the enzyme active site before an sp(3)-to-sp(2) transition during enzyme-mediated oxidation.

Apocynum venetum leaf attenuates myocardial ischemia/reperfusion injury by inhibiting oxidative stress.

Apocynum venetum, a Chinese medicinal herb, is reported to be neuroprotective. However, whether Apocynum venetum leaf extract (AVLE) protects against ischemic myocardium remains elusive. Our present study was aimed to observe the effects of AVLE preconditioning on myocardial ischemia/reperfusion (MI/R) injury and to investigate the possible mechanisms. Rats were treated with AVLE (500 mg/kg/d, o.g.) or distilled water once daily for one week. Afterward, all the animals were subjected to 30 min of myocardial ischemia followed by 4 h of reperfusion. AVLE preconditioning for one week significantly improved cardiac function following MI/R. Meanwhile, AVLE reduced infarct size, plasma creatine kinase (CK)/lactate dehydrogenase (LDH) activities and myocardial apoptosis at the end of reperfusion in rat hearts. Moreover, AVLE preconditioning significantly inhibited superoxide generation, gp91(phox) expression, malonaldialdehyde formation and enhanced superoxide dismutase (SOD) activity in I/R hearts. Furthermore, AVLE treatment increased Akt and extracellular regulated protein kinases 1/2 (ERK1/2) phosphorylations in I/R rat heart. Either the Phosphatidylinositide 3-kinase (PI3K) inhibitor wortmannin or the ERK1/2 inhibitor PD98059 blocked AVLE-stimulated anti-oxidative effects and cardioprotection. Our study demonstrated for the first time that AVLE reduces oxidative stress and exerts cardioprotection against MI/R injury in rats.

Loss of CD155 expression predicts poor prognosis in hepatocellular carcinoma.

AIMS: CD155 is an important ligand in triggering tumour rejection by immune cells. However, the expression of CD155 and its clinical significance in hepatocellular carcinoma (HCC) remains unknown. METHODS AND RESULTS: We examined the expression level of CD155 in 174 HCC tissue samples by immunohistochemical staining and in HCC cell lines by flow cytometry; 63.8% (111 of 174) of HCC tissue samples showed negative CD155 expression. When compared with adjacent peritumour tissues, HCC tissues exhibited a significantly lower expression of CD155 (P < 0.001). Flow cytometry analysis indicated that HCC cell lines had low levels of CD155 expression. Moreover, negative CD155 expression was associated significantly with higher serum α-fetoprotein level (P = 0.016) and a higher incidence of portal vein tumour thrombus (P = 0.050). Importantly, patients with positive CD155 expression had better overall survival after surgery than those with negative CD155 expression (P = 0.005). Furthermore, Cox regression analyses showed that CD155 expression was an independent prognostic factor for HCC (P = 0.049). CONCLUSIONS: Our findings suggest that loss of CD155 expression may play an important role in the immune escape of HCC cells and thus CD155 may serve as a prognostic marker as well as a potential therapeutic target for HCC.

Human α-amino-ß-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD): a structural and mechanistic unveiling.

Human α-amino-ß-carboxymuconate-ε-semialdehyde decarboxylase determines the fate of tryptophan metabolites in the kynurenine pathway by controlling the quinolinate levels for de novo nicotinamide adenine dinucleotide biosynthesis. The unstable nature of its substrate has made gaining insight into its reaction mechanism difficult. Our electron paramagnetic resonance (EPR) spectroscopic study on the Cu-substituted human enzyme suggests that the native substrate does not directly ligate to the metal ion. Substrate binding did not result in a change of either the hyperfine structure or the super-hyperfine structure of the EPR spectrum. We also determined the crystal structure of the human enzyme in its native catalytically active state (at 1.99 Å resolution), a substrate analogue-bound form (2.50 Å resolution), and a selected active site mutant form with one of the putative substrate binding residues altered (2.32 Å resolution). These structures illustrate that each asymmetric unit contains three pairs of dimers. Consistent with the EPR findings, the ligand-bound complex structure shows that the substrate analogue does not directly coordinate to the metal ion but is bound to the active site by two arginine residues through noncovalent interactions.

Melatonin Attenuates Noise Stress-induced Gastrointestinal Motility Disorder and Gastric Stress Ulcer: Role of Gastrointestinal Hormones and Oxidative Stress in Rats.

BACKGROUND/AIMS: There are increasing evidences for gastrointestinal motility disorder (GIMD) and gastric stress ulcer induced by noise stress. The present study was to investigate the reversed effect of melatonin on GIMD and gastric stress ulcer induced by noise stress and potential mechanism. METHODS: Noise stress was induced on rats, and melatonin (15 mg/kg) was administered to rats by intraperitoneal injection. Differences were assessed in gastric residual rate (GRR), small intestine propulsion rate (SPR), Guth injury score, cortisol, gastrointestinal hormones (calcitonin-gene-related peptide and motilin) and oxidative stress markers (superoxide dismutase and malondialde hyde) in blood plasma as well as gastric mucosa homogenate with or without melatonin. The pathological examination of gastric mucosa was also performed. RESULTS: The GRR and SPR were improved by noise stress compared with control (P < 0.05). The pathological examination and Guth injury score revealed gastric stress ulcer. Moreover, the levels of cortisol, motilin and malondialdehyde in blood plasma and ma-londialdehyde in gastric mucosa homogenate were increased by noise stress (P < 0.05). CGRP and superoxide dismutase activ-ity in both of blood plasma and gastric mucosa homogenate were significantly decreased (P< 0.05). Furthermore, melatonin reversed changes in GRR, SPR, pathological examination, Guth injury score, cortisol, motilin, CGRP, superoxide dismutase activity and malondialdehyde (P < 0.05). CONCLUSIONS: Melatonin is effective in reversing the GIMD and gastric stress ulcer induced by noise stress. The underlying mechanism may be involved in oxidative stress and gastrointestinal hormones.