A de novo mutation of ADAMTS8 in a patient with Wiedemann-Steiner syndrome.

BACKGROUND: Wiedemann-Steiner syndrome (WDSTS) is a rare autosomal dominant disorder caused by mutations in the KMT2A gene and is usually characterized by hairy elbows, short stature, developmental delay, intellectual disability and obvious facial dysmorphism. CASE PRESENTATION: Here, we report a 5-year-old girl with clinical features similar to WDSTS, including postnatal growth delay, retarded intellectual development, and ocular hypertelorism. Through whole-exome sequencing (WES), a frameshift variant of KMT2A was found in the patient but not in her parents' genomic DNA. By bioinformatics analysis, the KMT2A variant was demonstrated to be the top candidate pathogenic variant for the clinical phenotype consistent with WDSTS. Moreover, a duplication of exon 1 in ADAMTS8 (belonging to the zinc metalloproteinase family) was found in the genomic DNA of this patient, which may be responsible for the characteristics that are different from those of WDSTS, including early teething, rapid tooth replacement, and dysplastic enamel. CONCLUSIONS: From the above results, we propose that in our patient, the frameshift variant in KMT2A is the main reason for the WDSTS phenotype, and the unreported mutation in ADAMTS8 may be the candidate reason for other characteristics that are different from those of WDSTS. Therefore, this study not only provides a new KMT2A variant associated with WDSTS but is also a reminder that combined mutations may be present in a case with more characteristics than those seen in WDSTS.

m6A writer complex promotes timely differentiation and survival of retinal progenitor cells in zebrafish.

N6-Methyladenosine (m6A) is the most prevalent internal modification in eukaryotic mRNAs that modulates mRNA metabolism and function. Most m6A modifications on mRNAs are catalyzed by a core writer complex consisting of a methyltransferase, Mettl3, and two ancillary components, Mettl14 and Wtap. Recent studies have demonstrated important roles of m6A in various physiological and pathological processes, such as stem cell multipotency, cell differentiation, and cancer progression. However, our knowledge about m6A in the retina is still lacking. In this study, we used zebrafish as a model vertebrate to study the function of the m6A modification during retinal development. We show that the three main components of the m6A writer complex, mettl3, mettl14 and wtap, are abundantly expressed in the developing zebrafish eyes, and that knocking down m6A writer complex in zebrafish embryos caused microphthalmia formation, delayed retinal progenitor cells differentiation and increased cell death. By examining the retinal developmental processes in m6A writer complex-deficient fish, we show that m6A modification regulates zebrafish retinal development through ensuring the timely differentiation and survival of the retinal progenitor cells.

Tree distribution, morphology and modelled air pollution in urban parks of Hong Kong.

Trees offer a range of ecosystem services and remain important in providing human benefits. However, emerging literature questions the long-accepted view of trees being able to improve air quality in urban parks. The aerodynamic effect of trees was identified as a major reason for the change of pollutant distribution in near-road parks, where trees can act as porous barriers and cause localised concentration increase. Although not yet fully developed, planting strategies aiming to mitigate the negative effect of vegetation on air quality should be encouraged in future park design. In this study, we explored the effect of tree planting design on pollutant diffusion by integrating field surveys in urban parks in Hong Kong with computational fluid dynamic (CFD) modelling. A series of indicators associated with tree morphology and landscape were derived from the surveys and their influence on air pollutant distribution in parks was examined using ENVI-MET. Dense trees with low crown base were found effective in improving air quality within parks when planted as barriers with a width of ~15 m at borders. However, more extensive planting led to a decrease in wind velocity and an increase in pollutant concentrations, which should be avoided. Tall trees tended to have little influence on airflow at the pedestrian level, which means they seem appropriate for small urban parks where wide barriers are not applicable and rapid ventilation should be encouraged. The tree distribution also altered the airflow and pollutant dispersion in parks. Our study provides clues for thoughtful planting strategies which can optimise air quality in urban parks.

Irf4 Regulates the Choice between T Lymphoid-Primed Progenitor and Myeloid Lineage Fates during Embryogenesis.

T lymphoid-primed progenitors are hematopoietic progenitors destined to enter the thymus. The in vivo characterization of these embryonic progenitors is challenging, however, due to the intrauterine development of mouse embryos. Thus, how the fate of these cells is determined has not been fully defined in mammals. Here we use zebrafish embryos to show that the homing of T lymphoid-primed progenitors to the thymus is impaired, concomitant with a decrease in ccr9a expression, in the absence of irf4a. Strikingly, fate mapping assays at the single-cell level showed a fate change of irf4a-deficient T lymphoid-primed progenitors to myeloid cells, accompanied by an increase in Pu.1 expression. These data indicate that in addition to regulating ccr9a expression, Irf4a is essential in T lymphoid-primed progenitors for repressing Pu.1 expression to prevent an alternate fate. Our findings provide insight into the fate determination mechanism of T lymphoid-primed progenitors.

Knockdown of transcription factor forkhead box O3 (FOXO3) suppresses erythroid differentiation in human cells and zebrafish.

Our previous study on the dynamic transcriptomes activated during human erythropoiesis suggested that transcription factor forkhead box O3 (FOXO3) possibly plays a role in erythroid differentiation. Functional studies in human cell line TF-1 indicated that FOXO3 knockdown repressed erythropoietin (EPO)-induced erythroid differentiation by activating promoter region of B-cell translocation gene 1 (BTG1), thereby regulating its expression. In zebrafish, injection of foxo3b-specific morpholinos (foxo3b MO) resulted in reduced globin (hbae1 and hbbe2) and gata1 gene expression. Transcriptome analyses of erythroid lineage cells isolated from the control and foxo3b morphants revealed the dynamic regulation of foxo3b. Further study suggested that BTG1 is partially responsible for FOXO3 regulation in erythroid differentiation of TF-1 cells but is inconsequential in zebrafish. Taken together, we found that FOXO3 plays an important role in erythroid differentiation in both human TF-1 cells and zebrafish, but the mechanism underlying this regulation still remains unclear.

Inhibition of endothelial ERK signalling by Smad1/5 is essential for haematopoietic stem cell emergence.

The earliest HSCs are derived from haemogenic endothelium via endothelial-to-haematopoietic transition during vertebrate embryogenesis; however, the underlying mechanism is largely unclear. Here we show that interplay of Smad1/5 and ERK signalling is essential for haemogenic endothelium-based HSC emergence. Smad1/5 directly inhibits erk expression through recruiting HDAC1 to and inducing de-acetylation of the erk promoter in endothelial cells. Over-activated ERK signalling conferred by inhibition of Smad1/5 promotes the arterial endothelial cell fate and constitutively strengthens the tight junction between endothelial cells, thereby repressing the specification of haemogenic endothelium and the following endothelial-to-haematopoietic transition process. These findings provide new insights into the in vitro generation of transplantable HSCs for potential clinical applications.

Rapid determination of partition coefficients of pharmaceuticals by phase distribution and microchip capillary electrophoresis with contactless conductivity detection.

A simple microchip CE method integrated with contactless conductivity detection was developed for the direct determination of partition coefficients of selected pharmaceuticals after phase distribution equilibrium. The equilibrium of distribution between two phases for four pharmaceuticals was performed using a 1-octanol/water system and 1-octanol/buffer system. During the concentration determination, several major factors affecting detection were investigated in detail for each pharmaceutical to optimize the detection sensitivity. In the optimal conditions, sufficient electrophoretic separation and sensitive detection for each target analyte can be achieved within 40 s. The two systems showed a pH-dependent partition behavior. Moreover, the measured values showed excellent agreement with those obtained by the traditional shake-flask method with HPLC-UV detection and literature reports, respectively. The developed method can be successfully applied to measure partition coefficient values of pharmaceuticals and requires much shorter analytical time compared to traditional methods.

Foxn1 maintains thymic epithelial cells to support T-cell development via mcm2 in zebrafish.

The thymus is mainly comprised of thymic epithelial cells (TECs), which form the unique thymic epithelial microenvironment essential for intrathymic T-cell development. Foxn1, a member of the forkhead transcription factor family, is required for establishing a functional thymic rudiment. However, the molecular mechanisms underlying the function of Foxn1 are still largely unclear. Here, we show that Foxn1 functions in thymus development through Mcm2 in the zebrafish. We demonstrate that, in foxn1 knockdown embryos, the thymic rudiment is reduced and T-cell development is impaired. Genome-wide expression profiling shows that a number of genes, including some known thymopoiesis genes, are dysregulated during the initiation of the thymus primordium and immigration of T-cell progenitors to the thymus. Functional and epistatic studies show that mcm2 and cdca7 are downstream of Foxn1, and mcm2 is a direct target gene of Foxn1 in TECs. Finally, we find that the thymus defects in foxn1 and mcm2 morphants might be attributed to reduced cell proliferation rather than apoptosis. Our results reveal that the foxn1-mcm2 axis plays a central role in the genetic regulatory network controlling thymus development in zebrafish.

Molecular cloning and expression analysis of P-selectin glycoprotein ligand-1 from zebrafish (Danio rerio).

To date, the best characterized glycoprotein ligand for P-selectin is P-selectin glycoprotein ligand-1 (PSGL-1). In this study, we cloned the full-length cDNA of PSGL-1 from zebrafish (Danio rerio). Zebrafish PSGl-1 cDNA is 1,594 bp and encodes a putative 284 amino acid protein with a theoretical molecular weight of 30.33 kDa and isoelectric point of 7.96. A signal peptide of 27 amino acids is predicted. The putative protein contains an extracellular mucin-like domain, a transmembrane domain and a cytoplasmic domain, with homology to mammalian PSGL-1. In the putative P-selectin binding region, there are 1 potential tyrosine sulfation site and 12 potential threonine O-glycosylation sites. A single extracellular cysteine, at the junction of the extracellular and transmembrane domains, suggests a disulfide-bonding pattern. The amino acid sequence of zebrafish PSGL-1 is 19-22% identical to that of mammalian PSGL-1. RT-PCR and whole-mount in situ hybridization analysis revealed that zebrafish PSGL-1 was expressed in early embryonic development, and the expression has an increased trend from 0.2 (1-cell stage) to 72 hpf. The results indicate that the general domain structure of PSGL-1 protein is conserved among species, and zebrafish PSGL-1 plays important roles in embryonic development and probably has similar biological function to that of mammalian PSGL-1.

Toxicity induced by emodin on zebrafish embryos.

Emodin, a widely available herbal remedy, has a variety of pharmacological actions and valuable clinical applications. The potential effect of emodin on zebrafish (Danio rerio) embryos was evaluated. Zebrafish embryos were incubated with 0.1-2 µg/mL of emodin from 7 hours to 6 days postfertilization (dpf). Emodin, at concentrations of 0.25 µg/mL and above, negatively affected embryo survival and hatching success. Emodin induced a large suite of abnormalities on zebrafish embryos, such as edema, crooked trunk, and abnormal morphogenesis. To elucidate the mechanism of action, the transcript levels of drug-metabolism genes (CYP3A) and a multiple drug-resistance gene (MDR1) were detected by reverse-transcript polymerase chain reaction. Embryos showed increases in mRNA accumulation of CYP3A and MDR1. The above-described results indicated that emodin impaired zebrafish embryo development and some organ morphogenesis, and CYP3A and MDR1 were involved in the process. These findings suggest that emodin was toxic to zebrafish lavae at relatively low concentrations.

Isolation of chemical constituents from the aerial parts of Verbascum thapsus and their antiangiogenic and antiproliferative activities.

Phytochemical investigation of Verbascum thapsus led to the isolation and identification of one new iridoid compound named verbathasin A, along with ten known compounds. The structure and relative stereochemistry of verbathasin A were elucidated by analysis of spectroscopic data. All the isolates except 10-deoxyeucommiol and ajugol were tested for antiangiogenic and antiproliferative activities, and compounds luteolin and 3-O-fucopyranosylsaikogenin F showed promising antiproliferative activities, with an obvious effect of inducing apoptosis of A549 lung cancer cells.

Toxic effects of celastrol on embryonic development of zebrafish (Danio rerio).

Celastrol is a terpenoid purified from Tripterygium wilfordii Hook F. As a natural product with pharmacological activities, this compound is a promising candidate for drug development. To provide more information about its toxicity for clinical trials, toxicity assessment of celastrol was conducted with zebrafish model in vivo. 1hour post-fertilization (hpf) embryos were treated with various concentrations of celastrol for 120h. Developmental phenotypes were observed and survival rates were recorded. The results showed that the hatching rates of embryos treated with 1.0µM or higher celastrol were significantly lower. Embryos exposed to 1.0µM celastrol had no blood flow in trunk vessels at 48hpf with a median effect concentration (EC(50)) of 0.94µM. At 72hpf serious edema in pericardial sac was observed in the surviving larvae (hatched from embryos treated with 1.5µM celastrol). Bent tails or hook-like tails were seen as 0.5µM celastrol and the EC(50) for tail malformation was 0.66 µM at 72hpf. The lethal effect of celastrol on zebrafish embryos was dose-dependent and the LC(50) values of celastrol on 1hpf embryos were approximately 1.40µM. These results indicate that celastrol affects the normal development of zebrafish embryo in µM concentrations.

Molecular cloning and expression analysis of P-selectin from Zebrafish (Danio rerio).

The glycoprotein P-selectin belongs to the selectin family of cell adhesion molecules. In this study, we cloned the full-length cDNA of P-selectin from zebrafish (Danio rerio) by the method of rapid amplification of cDNA ends polymerase chain reaction (RACE-PCR). Zebrafish P-selectin cDNA is 2,800 bp and encodes a putative 868 amino acid protein with a theoretical molecular weight of 122.36 kDa and isoelectric point of 6.27. A signal peptide of 25 amino acids is predicted at the N-terminus of the putative protein. All structural domains involved in P-selectin function are conserved in the putative protein. The amino acid sequence of zebrafish P-selectin is 37% to 39% identical to that of mammalian P-selectins. Real-time quantitative PCR and whole-mount in situ hybridization analysis revealed that P-selectin was expressed in early embryonic development, the expression increased from 0.2 hpf (1-cell stage) to 72 hpf, and the expression significantly upregulated within 30 minutes of ADP induction. The results indicate that the structure of P-selectin protein is highly conserved among species and zebrafish P-selectin plays an important role in early embryonic development and probably has similar biological function to mammalian P-selectins.

Chemical constituents of Excoecaria acerifolia and their bioactivities.

A new kaurane diterpenoid, 3alpha,18-dihydroxy-3beta,20-epoxykaur-15-ene (1), was isolated from the aerial parts of Excoecaria acerifolia (Euphorbiaceae) together with 16 known compounds. Their structures were identified by extensive spectral analysis, especially 2D NMR techniques. Antiangiogenic effects of compounds 1-6 and 9-17 were evaluated using a zebrafish model, with compound 9 being active in this bioassay. At the same time, compounds 4, 6, 10, 11 showed activity in inhibiting the growth of A549 lung cancer cells, and the compound 10 also showed apoptosis-inducing effects on A549 lung cancer cells.

Chemical constituents from Clematis delavayi var. spinescens.

A new coumarin, 7-hydroxy-4,6-dimethoxy-5-methylcoumarin (1), was isolated from the aerial parts of Clematis delavayi var. spinescens together with 17 known compounds. Their structures were identified by extensive spectral analysis, especially 2D NMR techniques. Antiangiogenic effects of all compounds were evaluated using a zebrafish model.

Ingol and ingenol diterpenes from the aerial parts of Euphorbia royleana and their antiangiogenic activities.

Ten new ingol lathyrane-type diterpenes (1-10) and two known ingenol derivatives (11 and 12) were isolated from the aerial parts of Euphorbia royleana. The structures of 1-10 were elucidated on the basis of spectroscopic methods including 2D NMR analysis, and the structure of compound 1 was confirmed by single-crystal X-ray crystallography. Antiangiogenic effects of all compounds except for 5 were tested using a zebrafish model, with compounds 11 and 12 being active in this bioassay.

[Clinical applications of the postfemur island flap pedicled with the postfemur neurocutaneous nutrient vessel].

OBJECTIVE: To investigate the application of the island flap based on the postfemur neurocutaneous nutrient vessel. METHODS: The flap was designed and applied to repair the defects in the gluteal, popliteal fossa or the bilateral postfemur areas. A total of 11 cases (12 defects) were treated with this method. The size of the defects ranged from 4.0 cm x 7.8 cm to 8.3 cm x 16.6 cm. RESULTS: Of the 12 defects, 9 achieved complete success. Epidermal necrosis occurred in the distal part of the flap in 3 defects owing to venous stasis, which were cured with skin grafting. Postoperative follow-up for 8-19 months showed that the appearance, texture, and function of the flap were satisfactory. CONCLUSIONS: The advantages of the flap lie in the reliable blood supply, constant anatomy, and without sacrificing a major artery. The key points for the flap survival are utilizing the "Superficial vein-nutrient vessel of the cutaneous nerve system" and retaining a comet tail-shaped soft-tissue pedicle in the flap creation.