Loss of splicing factor IK impairs normal skeletal muscle development.

BACKGROUND: IK is a splicing factor that promotes spliceosome activation and contributes to pre-mRNA splicing. Although the molecular mechanism of IK has been previously reported in vitro, the physiological role of IK has not been fully understood in any animal model. Here, we generate an ik knock-out (KO) zebrafish using the CRISPR/Cas9 system to investigate the physiological roles of IK in vivo. RESULTS: The ik KO embryos display severe pleiotropic phenotypes, implying an essential role of IK in embryonic development in vertebrates. RNA-seq analysis reveals downregulation of genes involved in skeletal muscle differentiation in ik KO embryos, and there exist genes having improper pre-mRNA splicing among downregulated genes. The ik KO embryos display impaired neuromuscular junction (NMJ) and fast-twitch muscle development. Depletion of ik reduces myod1 expression and upregulates pax7a, preventing normal fast muscle development in a non-cell-autonomous manner. Moreover, when differentiation is induced in IK-depleted C2C12 myoblasts, myoblasts show a reduced ability to form myotubes. However, inhibition of IK does not influence either muscle cell proliferation or apoptosis in zebrafish and C2C12 cells. CONCLUSION: This study provides that the splicing factor IK contributes to normal skeletal muscle development in vivo and myogenic differentiation in vitro.

Hyaluronan-Stabilized Redox-Sensitive Nanoassembly for Chemo-Gene Therapy and Dual T1/T2 MR Imaging in Drug-Resistant Breast Cancer Cells.

Tailoring combinatorial therapies along with real-time monitoring strategies has been the major focus of overcoming multidrug resistance in cancer. However, attempting to develop a multifunctional nanoplatform in a single construct leads to compromising therapeutic outcomes. Herein, we developed a simple, theranostic nanoassembly containing a hyaluronic acid-stabilized redox-sensitive (HART) polyethylenimine polyplex composed of a doxorubicin (DOX) intercalated Bcl-2 shRNA encoded plasmid along with a green-synthesized hausmannite (Mn3O4) and hematite (Fe3O4) nanoparticle (GMF). The highly stable HART nanoassembly has enhanced CD44-mediated intracellular uptake along with hyaluronidase (hylase) and redox-responsive drug-gene release. With Bcl-2 gene silencing induced by the successful delivery of HART in multidrug-resistant MCF7 breast cancer cells, the synergistic cytotoxic effect of Bcl-2 silencing and DOX was achieved. In addition, the HART nanoassembly containing GMF exhibited excellent dual MRI contrast (T1/T2) by reducing artifact signals. Overall, the HART nanoassembly with its enhanced theranostic properties has the potential to improve the therapeutic efficacy in future preclinical and clinical trials.

Identification of new aryl hydrocarbon receptor (AhR) antagonists using a zebrafish model.

A new series of 1,3-diketone, heterocyclic and α,ß-unsaturated derivatives were synthesized and evaluated for their AhR antagonist activity using zebrafish and mammalian cells. Compounds 1b, 2c, 3b and 5b showed significant AhR antagonist activity in a transgenic zebrafish model. Among them, compound 3b, and 5b were found to have excellent AhR antagonist activity with IC50 of 3.36 nM and 8.3 nM in a luciferase reporter gene assay. In stem cell proliferation assay, compound 5b elicited marked HSC expansion.

Aggregation-prone GFAP mutation in Alexander disease validated using a zebrafish model.

BACKGROUND: Alexander disease (AxD) is an astrogliopathy that predominantly affects the white matter of the central nervous system (CNS), and is caused by a mutation in the gene encoding the glial fibrillary acidic protein (GFAP), an intermediate filament primarily expressed in astrocytes and ependymal cells. The main pathologic feature of AxD is the presence of Rosenthal fibers (RFs), homogeneous eosinophilic inclusions found in astrocytes. Because of difficulties in procuring patient' CNS tissues and the presence of RFs in other pathologic conditions, there is a need to develop an in vivo assay that can determine whether a mutation in the GFAP results in aggregation and is thus disease-causing. METHODS: We found a GFAP mutation (c.382G > A, p.Asp128Asn) in a 68-year-old man with slowly progressive gait disturbance with tendency to fall. The patient was tentatively diagnosed with AxD based on clinical and radiological findings. To develop a vertebrate model to assess the aggregation tendency of GFAP, we expressed several previously reported mutant GFAPs and p.Asp128Asn GFAP in zebrafish embryos. RESULTS: The most common GFAP mutations in AxD, p.Arg79Cys, p.Arg79His, p.Arg239Cys and p.Arg239His, and p.Asp128Asn induced a significantly higher number of GFAP aggregates in zebrafish embryos than wild-type GFAP. CONCLUSIONS: The p.Asp128Asn GFAP mutation is likely to be a disease-causing mutation. Although it needs to be tested more extensively in larger case series, the zebrafish assay system presented here would help clinicians determine whether GFAP mutations identified in putative AxD patients are disease-causing.

Novel NTRK1 mutations associated with congenital insensitivity to pain with anhidrosis verified by functional studies.

Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV, features loss of pain sensation, decreased or absent sweating (anhidrosis), recurrent episodes of unexplained fever, self-mutilating behavior, and variable mental retardation. Mutations in neurotrophic receptor tyrosine kinase 1 (NTRK1) have been reported to be associated with CIPA. We identified four novel NTRK1 mutations in six Korean patients from four unrelated families. Of the four mutations, we demonstrated using a splicing assay that IVS14+3A>T causes aberrant splicing of NTRK1 mRNA, leading to introduction of a premature termination codon. An NTRK1 autophosphorylation assay showed that c.1786G>A (p.Asp596Asn) abolished autophosphorylation of NTRK1. In addition, Western blotting showed that c.704C>G (p.Ser235*) and c.2350_2363del (p.Leu784Serfs*79) blunted NTRK1 expression to undetectable levels. The four novel NTRK1 mutations we report here will expand the repertoire of NTRK1 mutations in CIPA patients, and further our understanding of CIPA pathogenesis.

Zebrafish needle EMG: a new tool for high-throughput drug screens.

Zebrafish models have recently been highlighted as a valuable tool in studying the molecular basis of neuromuscular diseases and developing new pharmacological treatments. Needle electromyography (EMG) is needed not only for validating transgenic zebrafish models with muscular dystrophies (MD), but also for assessing the efficacy of therapeutics. However, performing needle EMG on larval zebrafish has not been feasible due to the lack of proper EMG sensors and systems for such small animals. We introduce a new type of EMG needle electrode to measure intramuscular activities of larval zebrafish, together with a method to hold the animal in position during EMG, without anesthetization. The silicon-based needle electrode was found to be sufficiently strong and sharp to penetrate the skin and muscles of zebrafish larvae, and its shape and performance did not change after multiple insertions. With the use of the proposed needle electrode and measurement system, EMG was successfully performed on zebrafish at 30 days postfertilization (dpf) and at 5 dpf. Burst patterns and spike morphology of the recorded EMG signals were analyzed. The measured single spikes were triphasic with an initial positive deflection, which is typical for motor unit action potentials, with durations of ∼10 ms, whereas the muscle activity was silent during the anesthetized condition. These findings confirmed the capability of this system of detecting EMG signals from very small animals such as 5 dpf zebrafish. The developed EMG sensor and system are expected to become a helpful tool in validating zebrafish MD models and further developing therapeutics.

Direct confirmation of quiescence of CD34+CD38- leukemia stem cell populations using single cell culture, their molecular signature and clinicopathological implications.

BACKGROUND: The proliferating activity of a single leukemia stem cell and the molecular mechanisms for their quiescent property remain unknown, and also their prognostic value remains a matter of debate. Therefore, this study aimed to demonstrate the quiescence property and molecular signature of leukemia stem cell and their clinicopathological implications. METHODS: Single cell sorting and culture were performed in the various sets of hematopoietic stem cells including CD34+CD38- acute myeloid leukemia (AML) cell population (ASCs) from a total of 60 patients with AML, and 11 healthy controls. Their quiescence related-molecular signatures and clinicopathological parameters were evaluated in AML patients. RESULTS: Single cell plating efficiency of ASCs was significantly lower (8.6%) than those of normal hematopoietic stem cells i.e.: cord blood, 79.0%; peripheral blood, 45.3%; and bone marrow stem cell, 31.1%. Members of the TGFß super-family signaling pathway were most significantly decreased; as well as members of the Wnt, Notch, pluripotency maintenance and hedgehog pathways, compared with non ASC populations. mtDNA copy number of ASCs was significantly lower than that of corresponding other cell populations. However, our data couldn't support the prognostic value of the ASCs in AML. CONCLUSIONS: ASCs showed remarkable lower plating efficiency and slower dividing properties at the single cell level. This quiescence is represented as a marked decrease in the mtDNA copy number and also linked with down-regulation of genes in various molecular pathways.

The prognostic impact of mutations in spliceosomal genes for myelodysplastic syndrome patients without ring sideroblasts.

BACKGROUND: Mutations in genes that are part of the splicing machinery for myelodysplastic syndromes (MDS), including MDS without ring sideroblasts (RS), have been widely investigated. The effects of these mutations on clinical outcomes have been diverse and contrasting. METHODS: We examined a cohort of 129 de novo MDS patients, who did not harbor RS, for mutations affecting three spliceosomal genes (SF3B1, U2AF1, and SRSF2). RESULTS: The mutation rates of SF3B1, U2AF1, and SRSF2 were 7.0 %, 7.8 %, and 10.1 %, respectively. Compared with previously reported results, these rates were relatively infrequent. The SRSF2 mutation strongly correlated with old age (P < 0.001), while the mutation status of SF3B1 did not affect overall survival (OS), progression-free survival (PFS), or acute myeloid leukemia (AML) transformation. In contrast, MDS patients with mutations in U2AF1 or SRSF2 exhibited inferior PFS. The U2AF1 mutation was associated with inferior OS in low-risk MDS patients (P = 0.035). The SRSF2 mutation was somewhat associated with AML transformation (P = 0.083). CONCLUSION: Our findings suggest that the frequencies of the SF3B1, U2AF1, and SRSF2 splicing gene mutations in MDS without RS were relatively low. We also demonstrated that the U2AF1 and SRSF2 mutations were associated with an unfavorable prognostic impact in MDS patients without RS.

KITENIN-targeting microRNA-124 suppresses colorectal cancer cell motility and tumorigenesis.

MicroRNAs are increasingly implicated in the modulation of the progression of various cancers. We previously observed that KAI1 C-terminal interacting tetraspanin (KITENIN) is highly expressed in sporadic human colorectal cancer (CRC) tissues and hence the functional KITENIN complex acts to promote progression of CRC. However, it remains unknown that microRNAs target KITENIN and whether KITENIN-targeting microRNAs modulate CRC cell motility and colorectal tumorigenesis. Here, through bioinformatic analyses and functional studies, we showed that miR-124, miR-27a, and miR-30b negatively regulate KITENIN expression and suppress the migration and invasion of several CRC cell lines via modulation of KITENIN expression. Through in vitro and in vivo induction of mature microRNAs using a tetracycline-inducible system, miR-124 was found to effectively inhibit the invasion of CT-26 colon adenocarcinoma cells and tumor growth in a syngeneic mouse xenograft model. Constitutive overexpression of precursor miR-124 in CT-26 cells suppressed in vivo tumorigenicity and resulted in decreased expression of KITENIN as well as that of MYH9 and SOX9, which are targets of miR-124. Thus, our findings identify that KITENIN-targeting miR-124, miR-27a, and miR-30b function as endogenous inhibitors of CRC cell motility and demonstrate that miR-124 among KITENIN-targeting microRNAs plays a suppressor role in colorectal tumorigenesis.

Feasible quantitative detection of cytomegalovirus from urine sediment in stem cell transplant patients.

BACKGROUND: Urine is an important source for the detection of infections caused by CMV in stem cell transplant patients. Currently, there is no agreement about the type of urine specimen. In order to investigate which is the better specimen type for quantitative detection of CMV, we compared the results from urine supernatant and sediment from the same patients. METHODS: Seventy urine specimens were collected from patients with hematological disorders or solid tumors. After performing shell vial culture, residual urine specimens were centrifuged. Then, 10 mL of each urine supernatant and sediment were taken and immediately frozen at -70 degrees C. Afterwards, archived urine specimens were thawed at room temperature and CMV-quantitative PCR was performed on both the supernatant and sediment fraction of urine. The results from each patient were reviewed for CMV antigenemia, blood shell vial culture, CMV-IgM or IgG, and clinical symptoms. RESULTS: CMV-qPCR results for the urine sediment fraction revealed a significant difference (p = 0.012) between the active CMV infection group and the latent CMV infection group. In addition, receiver operating characteristic curves for active CMV infection revealed that CMV-qPCR using urine sediment produced more accurate results than urine supernatant. CONCLUSIONS: These findings suggest that the sediment fraction of urine is a more suitable specimen in CMV-qPCR testing.

Angiopoietin-like 3 regulates hepatocyte proliferation and lipid metabolism in zebrafish.

Loss-of-function mutations in angiopoietin-like 3 (ANGPTL3) cause familial hypobetalipoproteinemia type 2 (FHBL2) in humans. ANGPTL3 belongs to the angiopoietin-like family, the vascular endothelial growth factor family that is structurally similar to angiopoietins and is known for a regulator of lipid and glucose metabolism, although it is unclear how mutations in ANGPTL3 lead to defect in liver development in the vertebrates. We report here that angptl3 is primarily expressed in the zebrafish developing liver and that morpholino (MO) knockdown of Angptl3 reduces the size of the developing liver, which is caused by suppression of cell proliferation, but not by enhancement of apoptosis. However, MO knockdown of Angptl3 did not alter angiogenesis in the developing liver. Additionally, disruption of zebrafish Angptl3 elicits the hypocholesterolemia phenotype that is characteristic of FHBL2 in humans. Together, our findings propose a novel role for Angptl3 in liver cell proliferation and maintenance during zebrafish embryogenesis. Finally, angptl3 morphants will serve as a good model for understanding the pathophysiology of FHBL2.

Discovery of novel arylpyridine derivatives for motile ciliogenesis.

Motile cilia are crucial for maintaining healthy bodily functions by facilitating fluid transport and removing foreign substances or debris from the body. The dysfunction of motile cilia leads to ciliopathy. In particular, damage to the motile cilia of the airways can cause or worsen respiratory disease, making it an attractive target for therapeutic interventions. However, there are no treatments to induce motile ciliogenesis. Forkhead box transcription factor J1 (FOXJ1), the master regulator, has been implicated in motile cilia formation. Mice lacking the Foxj1 gene show loss of axoneme, a key component of cilia, that further highlights the importance of FOXJ1 in motile cilia formation. This prompted us to identify new small molecules that could induce motile ciliogenesis. A phenotype-based high-throughput screening (HTS) in a Tg(foxj1a:eGFP) zebrafish model was performed and a novel hit compound was identified. Among the synthesized compounds, compound 16c effectively enhanced motile ciliogenesis in a transgenic zebrafish model. To further test the efficacy of compound 16c on a mammalian airway system consisting of multiciliated cells (MCCs), ex vivo mice tracheal epithelial cell culture was adopted under an air-liquid interface system (ALI). Compound 16c significantly increased the number of MCCs by enhancing motile ciliogenesis. In addition, compound 16c exhibited good liver microsomal stability, in vivo PK profiles with AUC, and oral bioavailability. There was no significant inhibition of CYP and hERG, and no cell cytotoxicity was shown. In an elastase-induced COPD (chronic obstructive pulmonary disease) mouse model, compound 16c effectively prevented the development and onset of COPD. Taken together, compound 16c has great promise as a therapeutic agent for treating and alleviating motile ciliopathies.

A common lipid links Mfn-mediated mitochondrial fusion and SNARE-regulated exocytosis.

Fusion of vesicles into target membranes during many types of regulated exocytosis requires both SNARE-complex proteins and fusogenic lipids, such as phosphatidic acid. Mitochondrial fusion is less well understood but distinct, as it is mediated instead by the protein Mitofusin (Mfn). Here, we identify an ancestral member of the phospholipase D (PLD) superfamily of lipid-modifying enzymes that is required for mitochondrial fusion. Mitochondrial PLD (MitoPLD) targets to the external face of mitochondria and promotes trans-mitochondrial membrane adherence in a Mfn-dependent manner by hydrolysing cardiolipin to generate phosphatidic acid. These findings reveal that although mitochondrial fusion and regulated exocytic fusion are mediated by distinct sets of protein machinery, the underlying processes are unexpectedly linked by the generation of a common fusogenic lipid. Moreover, our findings suggest a novel basis for the mitochondrial fragmentation observed during apoptosis.

Arcuate Nucleus of the Hypothalamus: Anatomy, Physiology, and Diseases.

The hypothalamus is part of the diencephalon and has several nuclei, one of which is the arcuate nucleus. The arcuate nucleus of hypothalamus (ARH) consists of neuroendocrine neurons and centrally-projecting neurons. The ARH is the center where the homeostasis of nutrition/metabolism and reproduction are maintained. As such, dysfunction of the ARH can lead to disorders of nutrition/metabolism and reproduction. Here, we review various types of neurons in the ARH and several genetic disorders caused by mutations in the ARH.

Biomineralized Nanoscavenger Abrogates Proinflammatory Macrophage Polarization and Induces Neutrophil Clearance through Reverse Migration during Gouty Arthritis.

The deposition of monosodium urate (MSU) crystals induces the overexpression of reactive oxygen species (ROS) and proinflammatory cytokines in residential macrophages, further promoting the infiltration of inflammatory leukocytes in the joints of gouty arthritis. Herein, a peroxidase-mimicking nanoscavenger was developed by forming manganese dioxide over albumin nanoparticles loaded with an anti-inflammatory drug, indomethacin (BIM), to block the secretion of ROS and COX2-induced proinflammatory cytokines in the MSU-induced gouty arthritis model. In the MSU-induced arthritis mouse model, the BIM nanoparticles alleviated joint swelling, which is attributed to the abrogation of ROS and inflammatory cytokine secretions from proinflammatory macrophages that induces neutrophil infiltration and fluid building up in the inflammation site. Further, the BIM nanoparticle treatment reduced the influx of macrophages and neutrophils in the injured region by blocking migration and inducing reverse migration in the zebrafish larva tail amputation model as well as in MSU-induced peritonitis and air pouch mouse models. Overall, the current strategy of employing biomineralized nanoscavengers for arthritis demonstrates clinical significance in dual blocking of peroxides and COX2 to prevent influx of inflammatory cells into the sites of inflammation.

Histone methyltransferase SETD3 regulates muscle differentiation.

Histone lysine methylation, as one of the most important factors in transcriptional regulation, is associated with a various physiological conditions. Using a bioinformatics search, we identified and subsequently cloned mouse SET domain containing 3 (SETD3) with SET (Su(var)3-9, Enhancer-of-zeste and Trithorax) and Rubis-subs-bind domains. SETD3 is a novel histone H3K4 and H3K36 methyltransferase with transcriptional activation activity. SETD3 is expressed abundantly in muscular tissues and, when overexpressed, activates transcription of muscle-related genes, myogenin, muscle creatine kinase (MCK), and myogenic factor 6 (Myf6), thereby inducing muscle cell differentiation. Conversely, knockdown of SETD3 by shRNA significantly retards muscle cell differentiation. In this study, SETD3 was recruited to the myogenin gene promoter along with MyoD where it activated transcription. Together, these data indicate that SETD3 is a H3K4/K36 methyltransferase and plays an important role in the transcriptional regulation of muscle cell differentiation.

A Genotype-Phenotype Study of Multiple Hereditary Exostoses in Forty-Three Patients.

Multiple hereditary exostoses (MHE) is a rare autosomal dominant skeletal disorder with a variety of clinical manifestations. We aimed to evaluate the general clinical phenotypic severity of MHE using our own scoring system and analyzed the risk factors associated with severe clinical phenotypes. In this study, 43 patients from 30 families were analyzed. The mutations were identified by direct sequencing of polymerase chain reaction-amplified genomic DNA or by multiplex ligation-dependent probe amplification. According to a new scoring system devised by the authors, the severity of the phenotype was assessed as mild, moderate, or severe based on the deformity of each segment, number of exostoses, leg length discrepancy, and functional limitations. Of 43 patients from 30 families, 39 patients (90.7%) and 24 families (80%) presented with EXT1 or EXT2 mutations. Patients with EXT1 mutations had a significantly worse phenotype than that of patients with EXT2 mutations or without any detectable mutation. The mean clinical score of patients with an EXT1 mutation (5.76; range, 2.0-8.0; SD = 1.60) was higher than that of patients with an EXT2 mutation (4.06; range, 2.0-7.0; SD = 1.47) or of those without any detectable mutation (4.63; range, 3.0-6.0; SD = 1.44; p = 0.005). According to our classification system, more patients with EXT1 mutations had 'severe disease' than those with EXT2 mutations. Deformity scores were also higher in patients with EXT1 mutations (p = 0.018). In the multivariate analysis, the deformity score was found to be associated with the 'severe' class (p = 0.031). In conclusion, 90.7% of patients with MHE showed EXT mutations. Our scoring system showed reliable results. We suggest that the extent of deformity is an important factor in determining the phenotype of MHE and close monitoring for the development of severe disease is recommended in patients with high deformity scores.

A Rapid and Noninvasive Method That Extracts Polymerase Chain Reaction-Ready Genomic DNA from Adult Zebrafish.

Genotyping usually entails analysis of the products of polymerase chain reaction (PCR) carried out with genomic DNA (gDNA) as template, and is employed for validation of mutant or transgenic organisms. For genotyping of adult zebrafish, gDNA is often extracted from clipped caudal fin or skin mucus through either alkaline lysis using NaOH or proteinase K (PK) treatment. Further purification of the gDNA using ethanol precipitation was optional. To develop a rapid and noninvasive method that extracts PCR-ready gDNA from adult zebrafish, we combined skin swabbing with PK treatment and demonstrated its efficiency. This method could be applied to a wide range of fish.

A novel in-frame GFAP p.E138_L148del mutation in Type II Alexander disease with atypical phenotypes.

Alexander disease (AxD) is a neurodegenerative astrogliopathy caused by mutation in the glial fibrillary acidic protein (GFAP) gene. A 42-year-old Korean man presented with temporary gait disturbance and psychiatric regression after a minor head trauma in the absence of bulbar symptoms and signs. Magnetic resonance images of the brain and spinal cord showed significant atrophy of the medulla oblongata and the entire spinal cord as well as contrast-enhanced T2 hypointensity in the basal ganglia. DNA sequencing revealed a novel 33-bp in-frame deletion mutation (p.Glu138_Leu148del) within the 1B rod domain of GFAP, which was predicted to be deleterious by PROVEAN analysis. To test whether the deletion mutant is disease-causing, we performed in vitro GFAP assembly and sedimentation assays, and GFAP aggregation assays in human adrenal carcinoma SW13 (Vim-) cells and rat primary astrocytes. All the assays revealed that GFAP p.Glu138_Leu148del is aggregation prone. Based on these findings, we diagnosed the patient with Type II AxD. This is a report that demonstrates the pathogenicity of InDel mutation of GFAP through functional studies. This patient's atypical presentation as well as the discrepancy between clinical symptoms and radiologic findings may extend the scope of AxD.