Publisher's note. Identification of a novel synonymous mutation in the human β-ureidopropionase gene UPB1 affecting pre-mRNA splicing

β-Ureidopropionase is the third enzyme of the pyrimidine degradation pathway and it catalyzes the conversion of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid to β-alanine and β-aminoisobutyric acid, respectively, and ammonia and CO2. To date, only 16 genetically confirmed patients with a complete ß-ureidopropionase deficiency have been reported. Here, we report the clinical, biochemical, and molecular analysis of a newly identified patient with β-ureidopropionase deficiency. Mutation analysis of the UPB1 gene showed that the patient was compound heterozygous for a novel synonymous mutation c.93C>T (p.Gly31Gly) in exon 1 and a previously described missense mutation c.977G>A (p.Arg326Gln) in exon 9. The in silico predicted effect of the synonymous mutation p.Gly31Gly on pre-mRNA splicing was investigated using a minigene approach. Wild-type and the mutated minigene constructs, containing the entire exon 1, intron 1, and exon 2 of UPB1, yielded different splicing products after expression in HEK293 cells. The c.93C>T (p.Gly31Gly) mutation resulted in altered pre-mRNA splicing of the UPB1 minigene construct and a deletion of the last 13 nucleotides of exon 1. This deletion (r.92 104delGCAAGGAACTCAG) results in a frame shift and the generation of a premature stop codon (p.Lys32SerfsX31). Using a minigene approach, we have thus identified the first synonymous mutation in the UPB1 gene, creating a cryptic splice-donor site affecting pre-mRNA splicing.

Activation of p38 MAPK in the rostral ventromedial medulla by visceral noxious inputs transmitted via the dorsal columns may contribute to pelvic organ cross-sensitization in rats with endometriosis

Whether visceral organ cross-sensitization is involved in endometriosis-associated pain remains elusive. Previous studies have shown that visceral noxious stimuli may trigger a cascade of signal transductions in the rostral ventromedial medulla (RVM) via the spinal dorsal column (DC) pathway and the RVM plays a critical role in the descending control of visceral nociception. In the current study, we hypothesized that the p38 mitogen-activated protein kinase (MAPK) activation in the RVM by noxious visceral inputs from ectopic growths via the DC was involved in the development of pelvic organ cross-sensitization in established endometriosis. A rat model of experimental endometriosis was established. To examine ectopic growths-to-colon cross-sensitization, graded colorectal distention (CRD) was performed and abdominal withdrawal reflex (AWR) scores were recorded in female rats at 8weeks after the uterine or fat (control) auto-transplantation. Western blot study was carried out to examine the phosphorylated form and the total level of p38 MAPK protein in the RVM. Our results showed that lesions of bilateral DCs immediately following uterine or fat auto-transplantation in female rats significantly attenuated the later development of ectopic growths-to-colon cross-sensitization and the increased p38 MAPK activation in the RVM, as compared to sham DC lesions. Furthermore, intra-RVM microinjection of a p38 MAPK inhibitor (SB 203580), but not vehicle, in female rats with established endometriosis significantly attenuated ectopic growths-to-colon cross-sensitization and the increased activation of p38 MAPK in the RVM. These findings suggest that the noxious inputs from ectopic growths may activate p38 MAPK in the RVM via the DC, which may contribute to the development of ectopic growths-to-colon cross-sensitization in established endometriosis.

Variation in the chicken LPIN2 gene and association with performance traits

The objective of the study was to investigate the distribution of LPIN2 variants and haplotypes among breeds and perform an association analysis of the variants and haplotypes with the broiler traits in chickens. Six breeds were used to study the variation and distribution of chicken LPIN2, and an F2 resource population was used to measure growth traits, carcass traits, meat quality traits and serum biochemistry parameters. A c.-599G>A variant was located in the promoter region of LPIN2 and c.444G>A and c.1730A>T (E577D) coding variant mutations were detected. Linkage disequilibrium tests showed that these three variants were under moderate linkage disequilibrium in the 6 breeds and 7 haplotypes were constructed. The distribution of variation/haplotypes presented clear differences among breeds. Association analysis showed that c.-599G>A was associated with leg muscle weight, jejunum length, ileum length, leg muscle fibre density and leg muscle fibre diameter; c.444G>A was associated with spleen weight, ileum length, body weight at hatch and metatarsus length at 8 weeks; c.1730T>A had significant effects on chicken liver weight, heart weight, body weight at 10 weeks, serum albumin and glucose. Diplotypes were significantly associated with body weight at hatch, heart weight, pancreas weight, duodenum length, leg muscle fibre density and lactate dehydrogenase.

Porphyromonas gingivalis lipopolysaccharides regulate functions of bone marrow mesenchymal stem cells

OBJECTIVES

Periodontitis is one of the most widespread inflammatory diseases; it causes tooth loss and is also associated with a variety of systemic diseases. Mesenchymal stem cells (MSCs) have been used to treat periodontitis. However, it is unknown whether bacterial toxins in the periodontal environment affect MSC-mediated periodontal regeneration. Porphyromonas gingivalis lipopolysaccharides (Pg-LPS) are key toxins for development of periodontitis. The purpose of the present study was to investigate effects of P. gingivalis LPS on biological properties of MSCs.

MATERIALS AND METHODS

Mesenchymal stem cells from bone marrow (BMMSCs) were treated with different concentrations of P. gingivalis LPS (0.1-10 μg/ml), then its effects were evaluated on biological properties of BMMSCs including proliferation, apoptosis, osteogenic differentiation and capacities to inhibit activated T cells.

RESULTS

Low concentration of P. gingivalis LPS (0.1 μg/ml) accelerated MSC proliferation, osteogenic differentiation and capacities to inhibit activated T cells via up-regulation of nitric oxide. However, high concentration of P. gingivalis LPS (10 μg/ml) reduced MSC proliferation, osteogenic differentiation and capacities to inhibit activated T cells.

CONCLUSIONS

Mesenchymal stem cells were functionally different following exposure to P. gingivalis LPS at the investigated concentrations. These findings suggest that MSC-mediated periodontal regeneration may be regulated by P. gingivalis LPS.

More effective glycaemic control by metformin in African Americans than in Whites in the prediabetic population

AIM

Metformin, a first-line diabetes drug, delays the onset of type 2 diabetes in the prediabetic population; however, in prediabetic patients, differences in glycaemic response to metformin among racial groups are unknown. We aimed to compare glucose-lowering effects of metformin between Whites and African Americans (AAs).

METHODS

We performed a secondary analysis using data from the diabetes prevention program, a multi-center randomized clinical trial, in which all participants were prediabetic. The metformin group (582 Whites and 210 AAs) received 850 mg of metformin twice daily, and was followed for 3 years.

RESULTS

We found that after 6 months on metformin, Whites had a drop of 3.89 ± 0.39 (mg/dL, mean ± SEM) in the fasting plasma glucose level, significantly less than that in African Americans (6.04 ± 0.72, P=0.006); at years 1 and 2, the differences were also significant. Consistently, the linear mixed model showed that, within 1 year of metformin treatment, the rate in reduction of glucose levels was more pronounced in AAs than in Whites (P=0.025 following adjustment for age and sex).

CONCLUSIONS

Therefore, AAs have a better glycaemic response to metformin treatment than Whites in the prediabetic population.

Platelet-activating factor receptor-mediated PI3K/AKT activation contributes to the malignant development of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide and occurs at a relatively high frequency in China, yet the mechanisms underlying its devastating outcome remain unclear. Here we report that platelet-activating factor receptor (PAFR), a type of G-protein-coupled receptor, was upregulated in ESCC tumors and cell lines, compared with controls; PAFR levels were positively correlated with ESCC clinical stages and survival time. Overexpression of PAFR promoted the malignant development of ESCC in vitro and in vivo, whereas depletion of PAFR suppressed these effects. Interestingly, PAFR was observed to activate PI3K/AKT (phosphatidylinositol 3-kinase/AKT) through the upregulation of FAK kinase activity. AKT-triggered nuclear factor-κB transcriptionally activated PAFR expression. This mutual positive regulation between PAFR and AKT was required for the aggressiveness of ESCC cells both in vitro and in vivo. Furthermore, treating mice bearing ESCC tumors with cholesterol-conjugated PAFR small interfering RNA effectively inhibited tumor progression and the expression of AKT-mediated oncogenic proteins. Taken together, we made the first demonstration that dysregulation of PAFR and the positive regulatory loop between PAFR and pAKT contribute to malignant progression of ESCC.

Construction and analysis of a suppression subtractive hybridization library of regeneration-related genes in soybean

The development of a genetic transformation system is needed to address the problem of the low efficiency associated with soybean regeneration. To contribute to the enhancement of the soybean regenerative capacity, we explored the developmental mechanisms of soybean regeneration at the molecular level using a suppression subtractive hybridization cDNA library constructed from cotyledonary nodes of soybean cultivar DN50. A total of 918 positive clones were identified and screened, with most inserted fragments ranging from 100 to 750 bp. Of these, 411 differentially expressed functional expressed sequence tags were identified and annotated based on their similarity to orthologs and paralogs detected in GenBank using the nucleotide and translated nucleotide Basic Local Alignment Search Tools. Functional analysis revealed that the associated genes were involved in signal transduction, synthesis, and metabolism of macromolecules, glucose and protein synthesis and metabolism, light and leaf morphogenesis, regulation of apoptosis, cell defense, cell wall differentiation, and a variety of hormone and cytokinin-mediated signaling pathways. The information uncovered in our study should serve as a foundation for the establishment of an efficient and stable genetic transformation system for soybean regeneration.

Folic acid supplementation and dietary folate intake, and risk of preeclampsia

BACKGROUND/OBJECTIVES

Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia.

SUBJECTS/METHODS

A birth cohort study was conducted in 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10,041 pregnant women without chronic hypertension or gestational hypertension were enrolled.

RESULTS

Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43-0.87). A significant dose-response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30-0.81) and late-onset (OR=0.60, 95% CI: 0.42-0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31-0.87, for the highest quartile of dietary folate intake compared with the lowest).

CONCLUSIONS

Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.

17β-oestradiol enhances global DNA hypomethylation in CD4-positive T cells from female patients with lupus, through overexpression of oestrogen receptor-α-mediated downregulation of DNMT1

BACKGROUND

Systemic lupus erythematosus (SLE) affects primarily women, and oestrogen appears to play a significant role in SLE development. Our previous studies showed that inhibition of DNA methyltransferase 1 (DNMT1) enhanced global DNA hypomethylation in CD4+ T cells isolated from patients with SLE, and exacerbated SLE. However, the effects of 17β-oestradiol on global DNA hypomethylation and DNMT1 expression in CD4+ T cells of female patients with SLE remain largely unknown.

AIM

To investigate the ability of 17β-oestradiol to affect global DNA methylation in female SLE CD4+ T cells and the mechanism(s) underlying this ability.

METHODS

We enrolled 30 women with SLE and 15 controls. CD4+ T cells exposed to 17β-oestradiol were analysed by global DNA methylation measurements, western blotting and real-time PCR. Plasma 17β-oestradiol levels were measured by ELISA.

RESULTS

In female SLE CD4+ T cells, 17β-oestradiol downregulated DNMT1 expression at both the mRNA and protein levels, and enhanced global DNA hypomethylation. Plasma 17β-oestradiol levels were similar in patients with SLE and controls. The mRNA expression of oestrogen receptor (ER)α, but not of ERβ, was upregulated in SLE CD4+ T cells. Furthermore, the 17β-oestradiol-induced downregulation of DNMT1 expression and global DNA hypomethylation were rescued by an ER antagonist.

CONCLUSIONS

17β-oestradiol enhances global DNA hypomethylation in female SLE CD4+ T cells via downregulation of DNMT1 mediated by ERα overexpression.

Enhanced biosynthesis of O-desmethylangolensin from daidzein by a novel oxygen-tolerant cock intestinal bacterium in the presence of atmospheric oxygen

AIMS

To improve the oxygen-tolerant capability of a newly isolated anaerobic bacterium and to biosynthesize O-desmethylangolensin (O-Dma) from daidzein aerobically.

METHODS AND RESULTS

After a long-term domestication process, an oxygen-tolerant bacterium, which we named Aeroto-AUH-JLC108, was derived from the newly isolated obligate anaerobic bacterium Clostridium sp. AUH-JLC108. Strain Aeroto-AUH-JLC108 differed from the natively anaerobic wild-type strain AUH-JLC108 by various characteristics, including a change in bacterial shape, biochemical characteristics and 16S rRNA gene sequences. Both the growth speed and the maximal optical density (OD) value of strain Aeroto-AUH-JLC108 grown aerobically were significantly increased compared to that of the wild-type strain grown anaerobically. The maximal concentration of the substrate daidzein that the oxygen-tolerant strain Aeroto-AUH-JLC108 grown aerobically was able to convert efficiently was 2.0 mmol l(-1) and 0.6 mmol l(-1) for strain AUH-JLC108 that was grown anaerobically.

CONCLUSIONS

Strain Aeroto-AUH-JLC108 is a conditional oxygen-tolerant bacterium. The growth speed, bacterial growth mass and bioconversion capability of strain Aeroto-AUH-JLC108 grown aerobically was significantly increased compared to that of the wild-type strain AUH-JLC108 grown anaerobically.

SIGNIFICANCE AND IMPACT OF THE STUDY

Strain Aeroto-AUH-JLC108 is the first reported pure culture responsible for the formation of O-Dma from daidzein in the presence of atmospheric oxygen.

TBX6 null variants and a common hypomorphic allele in congenital scoliosis

BACKGROUND

Congenital scoliosis is a common type of vertebral malformation. Genetic susceptibility has been implicated in congenital scoliosis.

METHODS

We evaluated 161 Han Chinese persons with sporadic congenital scoliosis, 166 Han Chinese controls, and 2 pedigrees, family members of which had a 16p11.2 deletion, using comparative genomic hybridization, quantitative polymerase-chain-reaction analysis, and DNA sequencing. We carried out tests of replication using an additional series of 76 Han Chinese persons with congenital scoliosis and a multicenter series of 42 persons with 16p11.2 deletions.

RESULTS

We identified a total of 17 heterozygous TBX6 null mutations in the 161 persons with sporadic congenital scoliosis (11%); we did not observe any null mutations in TBX6 in 166 controls (P<3.8×10(-6)). These null alleles include copy-number variants (12 instances of a 16p11.2 deletion affecting TBX6) and single-nucleotide variants (1 nonsense and 4 frame-shift mutations). However, the discordant intrafamilial phenotypes of 16p11.2 deletion carriers suggest that heterozygous TBX6 null mutation is insufficient to cause congenital scoliosis. We went on to identify a common TBX6 haplotype as the second risk allele in all 17 carriers of TBX6 null mutations (P<1.1×10(-6)). Replication studies involving additional persons with congenital scoliosis who carried a deletion affecting TBX6 confirmed this compound inheritance model. In vitro functional assays suggested that the risk haplotype is a hypomorphic allele. Hemivertebrae are characteristic of TBX6-associated congenital scoliosis.

CONCLUSIONS

Compound inheritance of a rare null mutation and a hypomorphic allele of TBX6 accounted for up to 11% of congenital scoliosis cases in the series that we analyzed. (Funded by the National Basic Research Program of China and others.).

In vivo Toll-like receptor 5 (TLR5) imaging with radiolabeled anti-TLR5 monoclonal antibody in rapamycin-treated mouse allogeneic skin transplantation model

BACKGROUND

In organ transplantation, increasing evidence, both in experimental and human studies, indicates that Toll-like receptor (TLR) activation is involved in the innate immune recognition of allograft. TLR5, the only protein recognition receptor of TLRs, is indicated potentially to be the immune regulation target. This study was designed to determine whether TLR5 could be a biomarker for in vivo allograft visualization, after immunosuppressant rapamycin treatment, using radiolabeled sodium iodide ((131) I)-anti-TLR5 monoclonal antibody (mAb).

METHODS

BALB/c mice were transplanted with C57BL/6 skin, with/without rapamycin treatment (the rapamycin-treated group and the phosphate buffered saline [PBS]-rejection group, respectively). In vivo dynamic whole-body phosphor-autoradiography and ex vivo biodistribution studies were conducted after (131) I-anti-TLR5 mAb injection.

RESULTS

Dynamic phosphor-autoradiography imaging showed clear graft localization from 12 h onward. At 72 h after injection, graft uptake quantified from images was higher for the rapamycin-treated group (26,448 ± 904 digital light units [DLU]/mm(2) ), compared with the PBS-treated allo-rejection group (9176 ± 576 DLU/mm(2) ). Treatment with anti-TLR5 mAb inhibited graft uptake. Organ biodistribution study reflected the same tendency, and (131) I-anti-TLR5 mAb uptake reached a maximum of 12.05 ± 1.86 %ID/g (percent injected dose per gram) at 1 h, and graft-to-native skin ratio reached 8.10 ± 0.10 %ID/g at 72 h after injection in rapamycin-treated grafts.

CONCLUSION

Radiolabeled anti-TLR5 mAb showed higher uptake in allo-treated grafts compared with allo-rejection grafts, which was proved by non-invasive dynamic phosphor-autoradiography imaging, and invasive ex vivo biodistribution. Radiolabeled anti-TLR5 mAb is a new tracer for non-invasive in vivo imaging of TLR5 in rapamycin-treated allograft.

A composite catalyst of reduced black TiO2−x/CNT: a highly efficient counter electrode for ZnO-based dye-sensitized solar cells

A composite catalyst (reduced black TiO_2−x/CNT) was synthesized through a simple sol–gel method and applied as a counter electrode in ZnO-based dye-sensitized solar cells. The resultant DSSCs achieved a PCE of 5.71%.

ATF3-mediated NRF2/HO-1 signaling regulates TLR4 innate immune responses in mouse liver ischemia/reperfusion injury

Activating transcription factor 3 (ATF3) is a stress-induced transcription factor that has been shown to repress inflammatory gene expression in multiple cell types and diseases. However, little is known about the roles and mechanisms of ATF3 in liver ischemia/reperfusion injury (IRI). In warm and cold liver IRI models, we showed that ATF3 deficiency significantly increased ischemia/reperfusion (IR)-stressed liver injury, as evidenced by increased serum alanine aminotransferase levels, histological liver damage, and hepatocellular apoptosis. These may correlate with inhibition of the intrahepatic nuclear factor erythroid-derived 2-related factor 2/heme oxygenase-1 (NRF2/HO-1) signaling pathway leading to enhancing Toll-like receptor 4/nuclear factor kappa beta (TLR4/NF-κB) activation, pro-inflammatory programs and macrophage/neutrophil trafficking, while simultaneously repressing anti-apoptotic molecules in ischemic liver. Interestingly, activation of NRF2/HO-1 signaling using an NRF2 activator, oltipraz (M2), during hepatic IRI-rescued ATF3 anti-inflammatory functions in ATF3-deficient mice. For in vitro studies, ATF3 ablation in lipopolysaccharide (LPS)-stimulated bone marrow-derived macrophages (BMMs) depressed levels of NRF2/HO-1 and PI3K/AKT, resulting in enhanced TLR4/NF-κB activation. Pretreatment of LPS-stimulated BMMs with M2 increased NRF2/HO-1 expression, promoted PI3K/AKT, which in turn suppressed TLR4/NF-κB-mediated proinflammatory mediators. Thus, our results first demonstrate ATF3-mediated NRF2/HO-1 signaling in the regulation of TLR4-driven inflammatory responses in IR-stressed livers. Our findings provide a rationale for a novel therapeutic strategy for managing IR-induced liver injury.

Modeling the effects of point and non-point source pollution on a diversion channel from Yellow River to an artificial lake in China

The Dragon lake diversion channel (DLDC) is the only river that recharges Dragon Lake, an artificial lake in China. This paper examines the main factors influencing water quality by investigating point source and non-point source pollutants along the main route. Based on the complicated system of rivers and desilting basins, a three-dimensional water quality model using environmental fluid dynamics code (EFDC) was developed. The model of DLDC was calibrated and verified using observed data. The error ranges of river water level, total phosphorus, total nitrogen and chemical oxygen demand were within 5%, 10%, 16% and 20%, respectively, all of which meet the precision requirement. The model was employed to predict the concentrations of pollutants in the main stream under current pollution loads within a year and a flood lasting for 24 hours. The results revealed that the main pollution sources that influence the water quality of waterways were the point sources followed by the non-point pollution sources. Water quality improved when large water quantities were delivered and this trend can be described as dilution. The water quality of the Dongfeng main channel meets the requirement; however, the water quality of the Dongfeng River is somewhat poor, and the water quality of the Wei River is seriously contaminated. To address these problems, we suggest that the Dongfeng River and Wei River adopt a culvert under its riverbeds.

A fibre forming smectic twist–bent liquid crystalline phase

We demonstrate the nanostructure and filament formation of a novel liquid crystal phase of a dimeric mesogen below the twist–bend nematic phase.

Effective uranium(vi) sorption from alkaline media using bi-functionalized silica-coated magnetic nanoparticles

A bi-functionalized magnetic iron oxide composite has been employed for uranium(vi) sorption from alkaline media. The maximum sorption capacity was observed at pH 9.0 with a capacity of 70.7 mg g⁻¹atc_U(vi)initial= 21.7 mg L⁻¹.