Improvement situation on indexes of the zebrafish disease model of non-alcoholic fatty liver disease with FGF21 analogues / 中华肝脏病杂志

Objective: To detect the therapeutic efficacy of FGF21 analogues on the zebrafish model of non-alcoholic fatty liver disease. Methods: A zebrafish model of non-alcoholic fatty liver disease was established by providing the normal diet fed to wild-type zebrafish three times daily. PF-05231023 was administered exogenously at a final concentration of 0.5 μmol/L. Body length, body weight, triglycerides, and other indexes were measured after 20 days. Pathological changes were evaluated in liver tissue sections by HE staining. Quantitative PCR was used to identify expressional changes in genes related to lipid metabolism, endoplasmic reticulum stress, and inflammation. Results: QPCR and immunofluorescence staining results showed that FGF21 was highly expressed in the zebrafish model group. The addition of the FGF21 analogue PF-05231023 significantly reduced the body length and body weight (P < 0.01), and the triglyceride content (P < 0.05) in the zebrafish model group. The liver HE staining results showed that PF-05231023 had alleviated the large and tiny bullae fat, lesions, and others in the zebrafish model group. The quantitative PCR results demonstrated that PF-05231023 reduced the expression of lipogenic factors (P < 0.01), inflammatory-related factors (P < 0.001), and genes related to endoplasmic reticulum stress (P < 0.05), but raised lipid-oxidation-related factors (P < 0.05) in the zebrafish model group. The addition of PF-05231023 reduced oleic acid-induced lipid and triglyceride levels in HepG2 cells. Conclusion: FGF21 analogue addition can improve indexes in the zebrafish disease model of non-alcoholic fatty liver disease.

Construction of fluorescent transgenic zebrafish Tg (ttn.2: EGFP) / 生物工程学报

In order to develop a transgenic zebrafish line with green fluorescent protein (enhanced green fluorescent protein, EGFP) expressed specifically in muscle and heart, the recombinant expression vector constructed using the zebrafish ttn.2 gene promoter fragment and EGFP gene coding sequence and the capped mRNA of Tol2 transposase were co-injected into the zebrafish 1-cell stage embryos. The stable genetic Tg (ttn.2: EGFP) transgenic zebrafish line was successfully developed by fluorescence detection, followed by genetic hybridization screening and molecular identification. Fluorescence signals and whole-mount in situ hybridization showed that EGFP expression was located in muscle and heart, the specificity of which was consistent with the expression of ttn.2 mRNA. Inverse PCR showed that EGFP was integrated into chromosomes 4 and 11 of zebrafish in No. 33 transgenic line, while integrated into chromosome 1 in No. 34 transgenic line. The successful construction of this fluorescent transgenic zebrafish line, Tg (ttn.2: EGFP), laid a foundation for the research of muscle and heart development and related diseases. In addition, the transgenic zebrafish lines with strong green fluorescence can also be used as a new ornamental fish.

Zebrafish ambra1b knockout reveals a novel role for Ambra1 in primordial germ cells survival, sex differentiation and reproduction

BACKGROUND: AMBRA1 is an intrinsically disordered protein, working as a scaffold molecule to coordinate, by protein-protein interaction, many cellular processes, including autophagy, mitophagy, apoptosis and cell cycle progression. The zebrafish genome contains two ambra1 paralogous genes (a and b), both involved in development and expressed at high levels in the gonads. Characterization of the zebrafish paralogous genes mutant lines generated by CRISPR/Cas9 approach showed that ambra1b knockout leads to an all-male population. RESULTS: We demonstrated that the silencing of the ambra1b gene determines a reduction of primordial germ cells (PGCs), a condition that, in the zebrafish, leads to the development of all-male progeny. PGC reduction was confirmed by knockdown experiments and rescued by injection of ambra1b and human AMBRA1 mRNAs, but not ambra1a mRNA. Moreover, PGC loss was not rescued by injection with human AMBRA1 mRNA mutated in the CUL4-DDB1 binding region, thus suggesting that interaction with this complex is involved in PGC protection from loss. Results from zebrafish embryos injected with murine Stat3 mRNA and stat3 morpholino suggest that Ambra1b could indirectly regulate this protein through CUL4-DDB1 interaction. According to this, Ambra1+/- mice showed a reduced Stat3 expression in the ovary together with a low number of antral follicles and an increase of atretic follicles, indicating a function of Ambra1 in the ovary of mammals as well. Moreover, in agreement with the high expression of these genes in the testis and ovary, we found significant impairment of the reproductive process and pathological alterations, including tumors, mainly limited to the gonads. CONCLUSIONS: By exploiting ambra1a and ambra1b knockout zebrafish lines, we prove the sub-functionalization between the two paralogous zebrafish genes and uncover a novel function of Ambra1 in the protection from excessive PGC loss, which seems to require binding with the CUL4-DDB1 complex. Both genes seem to play a role in the regulation of reproductive physiology.

Establishment of a microtubule-fluorescent fusion protein mosaically labeled zebrafish motor neuron system / 生理学报

Motor neurons are an important type of neurons that control movement. The transgenic fluorescent protein (FP)-labeled motor neurons of zebrafish line is disadvantageous for studying the morphogenesis of motor neurons. For example, the individual motor neuron is indistinguishable in this transgenic line due to the high density of the motor neurons and the interlaced synapses. In order to optimize the in vivo imaging methods for the analysis of motor neurons, the present study was aimed to establish a microtubule-fluorescent fusion protein mosaic system that can label motor neurons in zebrafish. Firstly, the promotor of mnx1, which was highly expressed in the spinal cord motor neurons, was subcloned into pDestTol2pA2 construct combined with the GFP-α-Tubulin fusion protein sequence by Gateway cloning technique. Then the recombinant constructs were co-injected with transposase mRNA into the 4-8 cell zebrafish embryos. Confocal imaging analysis was performed at 72 hours post fertilization (hpf). The results showed that the GFP fusion protein was expressed in three different types of motor neurons, and individual motor neurons were mosaically labeled. Further, the present study analyzed the correlation between the injection dose and the number and distribution of the mosaically labeled neurons. Fifteen nanograms of the recombinant constructs were suggested as an appropriate injection dose. Also, the defects of the motor neuron caused by the down-regulation of insm1a and kif15 were verified with this system. These results indicate that our novel microtubule-fluorescent fusion protein mosaic system can efficiently label motor neurons in zebrafish, which provides a more effective model for exploring the development and morphogenesis of motor neurons. It may also help to decipher the mechanisms underlying motor neuron disease and can be potentially utilized in drug screening.

Tripterygium wilfordii multiglycoside-induced hepatotoxicity via inflammation and apoptosis in zebrafish / 中国天然药物

Tripterygium wilfordii multiglycoside (GTW) is a commonly used compound for the treatment of rheumatoid arthritis (RA) and immune diseases in clinical practice. However, it can induce liver injury and the mechanism of hepatotoxicity is still not clear. This study was designed to investigate GTW-induced hepatotoxicity in zebrafish larvae and explore the mechanism involved. The 72 hpf (hours post fertilization) zebrafish larvae were administered with different concentrations of GTW for three days and their mortality, malformation rate, morphological changes in the liver, transaminase levels, and histopathological changes in the liver of zebrafish larvae were detected. The reverse transcription-polymerase chain reaction (RT-PCR) was used to examine the levels of microRNA-122 (miR-122) and genes related to inflammation, apoptosis, cell proliferation and liver function. The results showed that GTW increased the mortality of zebrafish larvae, while significant malformations and liver damage occurred. The main manifestations were elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), significant liver atrophy, vacuoles in liver tissue, sparse cytoplasm, and unclear hepatocyte contours. RT-PCR results showed that the expression of miR-122 significantly decreased by GTW; the mRNA levels of inflammation-related genes il1β, il6, tnfα, il10, cox2 and ptges significantly increased; the mRNA level of tgfβ significantly decreased; the mRNA levels of apoptosis-related genes, caspase-8 and caspase-9, significantly increased; the mRNA level of bcl2 significantly decreased; the mRNA levels of cell proliferation-related genes, top2α and uhrf1, significantly reduced; the mRNA levels of liver function-related genes, alr and cyp3c1, significantly increased; and the mRNA level of cyp3a65 significantly decreased. In zebrafish, GTW can cause increased inflammation, enhanced apoptosis, decreased cell proliferation, and abnormal expression of liver function-related genes, leading to abnormal liver structure and function and resulting in hepatotoxicity.

Expression optimization and molecular modification of heparin C5 epimerase / 生物工程学报

Heparin and heparan sulfate are a class of glycosaminoglycans for clinical anticoagulation. Heparosan N-sulfate-glucuronate 5-epimerase (C5, EC 5.1.3.17) is a critical modifying enzyme in the synthesis of heparin and heparan sulfate, and catalyzes the inversion of carboxyl group at position 5 on D-glucuronic acid (D-GlcA) of N-sulfoheparosan to form L-iduronic acid (L-IdoA). In this study, the heparin C5 epimerase gene Glce from zebrafish was expressed and molecularly modified in Escherichia coli. After comparing three expression vectors of pET-20b (+), pET-28a (+) and pCold Ⅲ, C5 activity reached the highest ((1 873.61±5.42) U/L) with the vector pCold Ⅲ. Then we fused the solution-promoting label SET2 at the N-terminal for increasing the soluble expression of C5. As a result, the soluble protein expression was increased by 50% compared with the control, and the enzyme activity reached (2 409±6.43) U/L. Based on this, site-directed mutations near the substrate binding pocket were performed through rational design, the optimal mutant (V153R) enzyme activity and specific enzyme activity were (5 804±5.63) U/L and (145.1±2.33) U/mg, respectively 2.41-fold and 2.28-fold of the original enzyme. Modification and expression optimization of heparin C5 epimerase has laid the foundation for heparin enzymatic catalytic biosynthesis.

Effect of dhfr gene overexpression on ethanol-induced abnormal cardiovascular development in zebrafish embryos / 中国当代儿科杂志

OBJECTIVE@#To study the effect of dhfr gene overexpression on ethanol-induced abnormal cardiac and vascular development in zebrafish embryos and underlying mechanisms.@*METHODS@#dhfr mRNA was transcribed in vitro and microinjected into zebrafish fertilized eggs to induce the overexpression of dhfr gene, and the efficiency of overexpression was verified. Wild-type zebrafish were divided into a control group, an ethanol group, and an ethanol+dhfr overexpression group (microinjection of 6 nL dhfr mRNA). The embryonic development was observed for each group. The transgenic zebrafish Tg (cmlc2:mcherry) with heart-specific red fluorescence was used to observe atrial and ventricular development. Fluorescence microscopy was performed to observe the development of cardiac outflow tract and blood vessels. Heart rate and ventricular shortening fraction were used to assess cardiac function. Gene probes were constructed, and embryo in situ hybridization and real-time PCR were used to measure the expression of nkx2.5, tbx1, and flk-1 in the embryo.@*RESULTS@#Compared with the ethanol group, the ethanol+dhfr overexpression group had a significant reduction in the percentage of abnormal embryonic development and a significant increase in the percentage of embryonic survival (P<0.05), with significant improvements in the abnormalities of the atrium, ventricle, outflow tract, and blood vessels and cardiac function. Compared with the control group, the ethanol group had significant reductions in the expression of nkx2.5, tbx1, and flk-1 (P<0.05), and compared with the ethanol group, the ethanol+dhfr overexpression group had significant increases in the expression of nkx2.5, tbx1, and flk-1 (P<0.05), which were still lower than their expression in the control group.@*CONCLUSIONS@#The overexpression of the dhfr gene can partially improve the abnormal development of embryonic heart and blood vessels induced by ethanol, possibly by upregulating the decreased expression of nkx2.5, tbx1, and flk-1 caused by ethanol.

Establishment and preliminary mechanism study of the zebrafish strain of KIAA0196: A candidate pathogenic gene for heart development / 中南大学学报(医学版)

To explore the effects of KIAA0196 gene on cardiac development and the establishment of zebrafish strain.
 Methods: Peripheral blood and gDNA from patients were extracted. Copy number variation analysis and target sequencing were conducted to screen candidate genes. The KIAA0196 knockout zebrafish was generated by CRISPR/Cas9 to detect whether KIAA0196 deficiency could affect cardiac development. Finally, the wild-type and mutant zebrafish were anatomized and histologically stained to observe the phenotype of heart defects.
 Results: The KIAA0196 knockout zebrafish strain was successfully constructed using CRISPR/Cas9 technology. After 60 hours fertilization, microscopic examination of KIAA0196 knockout zebrafish (heterozygote + homozygote) showed pericardial effusion, cardiac compression and severely curly tail. Compared with wild-type zebrafish, the hearts of mutant KIAA0196 zebrafish had cardiac defects including smaller atrium and larger ventricle, and the myocardial cells were looser.
 Conclusion: KIAA0196 gene plays an important regulatory role in the development of heart. It might be a candidate gene for congenital heart disease.

Effect of Huangdi Anxiao Capsules on zebrafish vascular lesions induced by high glucose and high fat / 中国中药杂志

Zebrafish of different strains with 5 dpf (5 days post-fertilization) were selected and fed with 0.2% high-fat diet for 8 h and 3% glucose solution for 16 halternatively during the day and night for 4 consecutive days. The zebrafish model was established and randomly divided into model group, Huangdi Anxiao Capsules (260 mg·L⁻¹) group and pioglitazone (32 mg·L⁻¹) group. The drug treatment groups were given the water-soluble drugs, with a volume of 25 mL, and incubated in a 28 °C incubator for 4 days. To detect the exposure to the corresponding drugs, the normal control group was set up. Thirty zebrafish were included in each group. The effect of Huangdi Anxiao Capsules on vascular wall thickness, fluorescence intensity of islet beta cells, fluorescence intensity of macrophages, and blood flow velocity of zebrafish were detected. The expressions of vascular endothelial growth factor (vegfaa) and angiotensin converting enzyme (ACE) were detected by RT-PCR. The results showed that compared with the model group, Huangdi Anxiao Capsules can significantly reduce the thickness of the blood vessel wall, increase the fluorescence intensity of islet β cells and macrophages, increase the blood flow velocity in vivo, and decrease the ACE and vegfaa expressions in zebrafish. It is suggested that Huangdi Anxiao Capsules may alleviate zebrafish vascular lesions by regulating the expressions of ACE and vegfaa.

Natriuretic peptide precursor C coding gene contributes to zebrafish angiogenesis / 生理学报

This study aimed to investigate the expression of the natriuretic peptide precursor C coding gene nppc and its role in angiogenesis during embryonic period of the zebrafish. Whole mount in situ hybridization was performed to detect the expression pattern of nppc. nppc specific morpholino and nppc mRNA were injected respectively into the one-cell stage embryo to specifically knock-down and rescue the expression of nppc in Tg (flk1:GFP) and Tg (fli1a:nGFP) transgenic lines. The morphology and endothelial cell number of intersegmental vessel (ISV) were analyzed after imaging using the laser scanning confocal microscope. The results revealed that nppc was expressed in the brain, heart and vasculature of zebrafish larvae at 24 and 48 hours post-fertilization (hpf). Knock-down of nppc affected the development of ISV. Endothelial cell number was reduced after the knock-down of nppc. These results suggest that nppc controls zebrafish angiogenesis by affecting the endothelial cell proliferation and migration.

Generation and phenotype analysis of zebrafish mutations of obesity-related genes lepr and mc4r / 生理学报

Obesity has become a severe public health problem across the world, and seriously affects the health and life quality of human beings. Here we generated lepr and mc4r mutant zebrafish via the CRISPR/Cas9 technique, and performed morphological and functional characterizations of those mutants. We observed that there was no significant phenotypic difference between homozygous mutants and wild-type controls before 2.5 months post-fertilization (mpf). However, the adult leprand mc4rindividuals displayed increased food intake, heavier weight, and higher body fat percentage, the characteristics of obesity phenotypes. Blood glucose test showed that overfeeding induced significantly impaired glucose tolerance in adult leprand mc4rzebrafish. Furthermore, we analyzed 76 energy metabolism-related transcripts in leprand mc4rzebrafish livers by using real-time RT-PCR, and compared the results with the published microarray data of Lepmouse livers, and found that the changes in the expression of insulin/IGF signaling (IIS) pathway genes in leprzebrafish and Lepmouse were positively correlated, suggesting that the IIS pathway maintains functional conservation between zebrafish and mammals during the evolution of the obesity-regulating molecule network.

Generation of tnnt2a knock-out zebrafish via CRISPR/Cas9 and phenotypic analysis / 生理学报

Cardiac troponin T (cTnT) serves as a structural protein of myocardial fiber, and participates in heart excitation-contraction coupling process. Here, we generated tnnt2a (cTnT-coding gene) deletion mutant zebrafish via CRISPR/Cas9 technique, and performed phenotypic analysis of the identified tnnt2a mutants. We observed that there was no significant difference between heterozygous mutant and wild type zebrafish, and the homozygous mutants displayed significant malformations in heart, including cardiac arrest, atrium and ventricle enlargement, pericardium effusion, and the individuals usually died before 7 day post fertilization (dpf). We further analyzed the expression alternations of heart sarcomere genes (tnnt2a, actc1a, tpm4a, myl7, vmhc) at transcriptional level in tnnt2a(Δ2) zebrafish by performing real time RT-PCR, and found that the RNA expression level of tnnt2a in tnnt2azebrafish decreased constantly at each time point of developmental stages, and actc1a, tpm4a, myl7 and vmhc all showed higher expressions at early developmental stages and lower expressions at late developmental stages, in comparison with those of wild type zebrafish. Lastly, electron microscopy on cardiac tissues suggested that there were significant changes of the thick or thin filament structures in tnnt2a(Δ2) zebrafish, which was further confirmed by F-actin and Tpm4 immunofluorescence staining. The tnnt2azebrafish generated by CRISPR/Cas9 bears the most common symptoms of patients with dilated cardiomyopathy, and therefore can be used as a tool to study TNNT2-deficiency related cardiomyopathy.

Expression of osterix gene in the early stage of cranio-maxillofacial development in zebrafish / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the expression patterns of osterix in the early stage of cranio-maxillofacial developmental in zebrafish and to prepare for a further research of osterix gene in bone and tooth development.</p><p><b>METHODS</b>The osterix templates were amplified by PCR to generate DIG labeled antisense and sense probes. Whole mount in situ hybridization was used to analyze the expression patterns of osterix in the early stage cranio-maxillofacial development of zebrafish. The expression patterns of osterix gene in mineralization progresses of cranial and maxillofacial bones were compared. The osterix gene expression in tooth development and mineralization was highlighted by alizarin red staining.</p><p><b>RESULTS</b>Specific DIG labeled probes of osterixwere synthesized successfully. The whole mount in situ hybridization showed that the osterix expression was in the intramembranous ossification at 3 days post fertilization(dpf) and 4 dpf. The specific osterix expression in tooth at 5 dpf and 6 dpf were also observed. The sense probe served as a negative control. Osterix expressed in the unmineralized early bone matrix, the tooth matrix of the primary tooth(3V(1), 5V(1)) and the first replacement tooth(4V(2)).</p><p><b>CONCLUSIONS</b>Our findings showed that osterix might play roles in the process of the early mineralized bone matrix changing into the late mature mineralized bone matrix and the process of development and mineralization of tooth crown matrix.</p>

Preoperative Imaging Modalities to Predict the Risk of Regional Nodal Recurrence in Well-Differentiated Thyroid Cancers

Introduction Thyroid cancer incidence has increased in the previous 2 decades. Preoperative identification of lymph node metastasis is a suggested risk factor associated with recurrence following thyroidectomy. Objectives We aimed to evaluate the accuracy of preoperative radiologic investigations of nodal status in determining the postoperative risk of regional nodal recurrence in cases of well-differentiated thyroid cancer. Methods This is a case series. We retrospectively reviewed data, including preoperative ultrasonography and/or computed tomography results, on patients who underwent total thyroidectomy for thyroid cancer at our hospital between 2006 and 2012. Prognostic factors for predicting recurrence, including age, sex, tumor diameter, and nodal diameter, were evaluated. Results Total thyroidectomy was performed on 24 male and 74 female patients (median age, 43 years). The median follow-up time was 21 months. Sixty-eight patients had papillary thyroid cancer, and 30 had follicular cancer. Nodal recurrence was evident in 30% of patients, and 4% of patients died. Identification of lymph node involvement during preoperative radiologic investigations was strongly prognostic for recurrence: 35.3% of patients with positive preoperative ultrasonography findings and 62.5% of those with positive preoperative computed tomography findings had recurrence (p = 0.01). Conclusions Preoperative identification of lymph node metastasis on radiologic studies was correlated with an increased risk of regional nodal recurrence in well-differentiated thyroid cancer. Computed tomography was superior to ultrasonography in detecting metastatic nodal involvement preoperatively and is therefore recommended for preoperative assessment and postoperative follow-up. .

Is there a relationship between complaints of impaired balance and postural control disorder in community-dwelling elderly women? A cross-sectional study with the use of posturography

Background: Risk of falls increases as age advances. Complaints of impaired balance are very common in the elderly age group. Objectives: The objective of this study was to investigate whether the subjective perception of impaired balance was associated with deficits in postural control (objective analysis) in elderly community-dwelling women. Method: Static posturography was used in two groups: elderly women with (WC group) and without (NC group) complaints of impaired balance. The area, mean sway amplitude and mean speed of the center of pressure (COP) in the anterior-posterior (AP) and medial-lateral (ML) directions were analyzed in three stances: single-leg stance, double-leg stance and tandem stance, with eyes open or closed on two different surfaces: stable (firm) and unstable (foam). A digital chronometer was activated to measure the time limit (Tlimit) in the single-leg stance. Kruskal-Wallis tests followed by Mann-Whitney tests, Friedman analyses followed by post hoc Wilcoxon tests and Bonferroni corrections, and Spearman statistical tests were used in the data analysis. Differences of p<0.05 were considered statistically significant. Results: The results of posturography variables revealed no differences between groups. The timed single-leg stance test revealed a shorter Tlimit in the left single-leg stance (p=0.01) in WC group compared to NC group. A negative correlation between posturography variables and Tlimit was detected. Conclusions: Posturography did not show any differences between the groups; however, the timed single-leg stance allowed the authors to observe differences in postural control performance between elderly women with and those without complaints of impaired balance. .

Toxic effects of strychnine and strychnine N-oxide on zebrafish embryos / 中国天然药物

AIM@#The application of strychnine (S) is limited due to its toxicity; strychnine N-oxide (SNO) is a derivative of strychnine. The aim was to employ zebrafish embryos to investigate and compare the developmental toxicity induced by S and SNO.@*METHODS@#The toxicity of S and SNO was examined through the hatching rate and survival rate. Morphological changes of the zebrafish were observed with a dissecting microscope. Apoptosis was detected through acridine orange (AO) staining and flow cytometry. Apoptotic genes were measured by RT-PCR.@*RESULTS@#Embryo malformation was observed in the embryos exposed to S at 200 μmol·L(-1). When SNO concentration was increased to 1 mmol·L(-1), scoliolosis, and pericardial edema could be seen in some embryos. Results from fluorescence microscopy and flow cytometry analysis showed that S at 200 μmol·L(-1) induced apoptosis, whereas the apoptotic rate in the SNO-treated group (200 μmol·L(-1)) was much lower than that in the S group. RT-PCR analysis showed that p53 mRNA expression and the ratio of Bax/Bcl-2 in the S group were significantly altered compared with the control group (*P < 0.05). Moreover, Bax mRNA expression in both S and SNO group were significantly different from that in the control group (**P < 0.01).@*CONCLUSION@#These results lead to the conclusion that SNO has significantly lower toxicity than S in zebrafish embryos.

Effect of beclin1 on vincristine-induced dopaminergic neurons injury in zebrafish / 药学学报

To investigate vincristine-induced dopaminergic neurons toxicity and mechanism, and explore the molecular target to reduce the toxicity, zebrafish was chosen as a model animal, based on RT-PCR, Western blotting, whole mount in situ immunofluorescence and other technical means. The results showed that the transcription levels of tyrosine hydroxylase gene and dopamine transporter protein gene were inhibited. Furthermore, the number of dopaminergic neurons was decreased by vincristine. Autophagy was suppressed and beclin1 gene expression was inhibited in a dose-dependent manner by vincristine in larval zebrafish. Up-regulated beclin1 partly reduced vincristine-induced neurotoxicity, and down-regulated beclin1 increased toxicity. Beclin1 plays an important role in vincristine-induced dopaminergic neurons toxicity.

Role of histone deacetylase activity in the developing lateral line neuromast of zebrafish larvae

Histone deacetylases are involved in many biological processes and have roles in regulating cell behaviors such as cell cycle entry, cell proliferation and apoptosis. However, the effect of histone deacetylases on the development of hair cells (HCs) has not been fully elucidated. In this study, we examined the influence of histone deacetylases on the early development of neuromasts in the lateral line of zebrafish. Hair cell development was evaluated by fluorescent immunostaining in the absence or presence of histone deacetylase inhibitors. Our results suggested that pharmacological inhibition of histone deacetylases with inhibitors, including trichostatin A, valproic acid and MS-275, reduced the numbers of both HCs and supporting cells in neuromasts. We also found that the treatment of zebrafish larvae with inhibitors caused accumulation of histone acetylation and suppressed proliferation of neuromast cells. Real-time PCR results showed that the expression of both p21 and p27 mRNA was increased following trichostatin A treatment and the increase in p53 mRNA was modest under the same conditions. However, the expression of p53 mRNA was significantly increased by treatment with a high concentration of trichostatin A. A high concentration of trichostatin A also led to increased cell death in neuromasts as detected in a TUNEL assay. Moreover, the nuclei of most of these pyknotic cells were immunohistochemically positive for cleaved caspase-3. These results suggest that histone deacetylase activity is involved in lateral line development in the zebrafish and might have a role in neuromast formation by altering cell proliferation through the expression of cell cycle regulatory proteins.

Retinol dehydrogenase, RDH1l, is essential for the heart development and cardiac performance in zebrafish / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Retinoic acid (RA) is a potent signaling molecule that plays pleiotropic roles in patterning, morphogenesis, and organogenesis during embryonic development. The synthesis from retinol (vitamin A) to retinoic acid requires two sequential oxidative steps. The first step involves the oxidation of retinol to retinal through the action of retinol dehydrogenases. Retinol dehydrogenases1l (RDH1l) is a novel zebrafish retinol dehydrogenase. Herein we investigated the role of zebrafish RDH1l in heart development and cardiac performance in detail.</p><p><b>METHODS</b>RDH1l specific morpholino was used to reduce the function of RDH1l in zebrafish. The gene expressions were observed by using whole mount in situ hybridization. Heart rates were observed and recorded under the microscope from 24 to 72 hours post fertilization (hpf). The cardiac performance was analyzed by measuring ventricular shortening fraction (VSF).</p><p><b>RESULTS</b>The knock-down of RDH1l led to abnormal neural crest cells migration and reduced numbers of neural crest cells in RDH1l morphant embryos. The reduced numbers of cardiac neural crest cells also can be seen in RDH1l morphant embryos. Furthermore, the morpholino-mediated knock-down of RDH1l resulted in the abnormal heart loop. The left-right determining genes expression pattern was altered in RDH1l morphant embryos. The impaired cardiac performance was observed in RDH1l morphant embryos. Taken together, these data demonstrate that RDH1l is essential for the heart development and cardiac performance in zebrafish.</p><p><b>CONCLUSIONS</b>RDH1l plays a important role in the neural crest cells development, and then ultimately affects the heart loop and cardiac performance. These results show for the first time that an enzyme involved in the retinol to retinaldehyde conversion participate in the heart development and cardiac performance in zebrafish.</p>

Impaired effect of BHC80 gene knock-down on the cardiac development in zebrafish / 生理学报

The effect of BHC80 (a component of BRAF-HDAC complex) on development was not well studied, because BHC80 gene knock-out mice died in one day after birth. Interestingly, zebrafish embryos can live, even if their important organs like cardiac system has severe dysfunction, as 25%-40% O2 are supplied through their skin. Therefore, a model of BHC80 gene knock-down zebrafish embryos was established to explore the effect of BHC80 on the early embryonic development. BHC80-morpholino antisense oligonucleotides 2 (BHC80-MO2) was designed and injected into zebrafish embryos to interrupt the correct translation of BHC80 mRNA at one or two cells stage, which was proved by RT-PCR analysis. Two control groups, including non-injection group and control-MO (con-MO) injection group, and four different doses of BHC80-MO2 injection groups, including 4 ng, 6 ng, 8 ng and 10 ng per embryo were set up. The embryonic heart phenotype and cardiac function were monitored, analyzed and compared between con-MO and BHC80-MO2 groups by fluorescence microscope in vmhc:gfp transgenic zebrafish which express green fluorescent protein in ventricle. The results showed that BHC80-MO2 microinjection effectively knocked down the BHC80 gene expression, because the BHC80-MO2 group emerged a new 249 bp band which reduced 51 bp compared to 300 bp band of con-MO group in RT-PCR analysis, and the 51 bp was the extron 10. The abnormal embryo rate rose with the increase of BHC80-MO2 dosage. The proper BHC80-MO2 injection dosage was 8 ng per embryo, as minor embryos had abnormal phenotype in 4 ng and 6 ng per embryo groups and most embryos died in 10 ng per embryo group. BHC80-MO2 embryos exhibited abnormal cardiac phenotype, including imbalance of the proportion of heart ventricle to atrium, incomplete D-loop, even tubular heart, slow heart rates and cardiac dysfunction. The results from a model of BHC80 gene knock-down zebrafish embryos show that the abnormal cardiac phenotype and cardiac dysfunction of BHC80-MO2 embryos may be one of the probable reasons for the BHC80 gene knock-out mice death, which would provide a good research model to clarify the mechanism of cardiac development.