Identification of potential biomarkers for ankylosing spondylitis based on bioinformatics analysis.

OBJECTIVE: The aim of this study was to search for key genes in ankylosing spondylitis (AS) through comprehensive bioinformatics analysis, thus providing some theoretical support for future diagnosis and treatment of AS and further research. METHODS: Gene expression profiles were collected from Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo/ ) by searching for the term "ankylosing spondylitis". Ultimately, two microarray datasets (GSE73754 and GSE11886) were downloaded from the GEO database. A bioinformatic approach was used to screen differentially expressed genes and perform functional enrichment analysis to obtain biological functions and signalling pathways associated with the disease. Weighted correlation network analysis (WGCNA) was used to further obtain key genes. Immune infiltration analysis was performed using the CIBERSORT algorithm to conduct a correlation analysis of key genes with immune cells. The GWAS data of AS were analysed to identify the pathogenic regions of key genes in AS. Finally, potential therapeutic agents for AS were predicted using these key genes. RESULTS: A total of 7 potential biomarkers were identified: DYSF, BASP1, PYGL, SPI1, C5AR1, ANPEP and SORL1. ROC curves showed good prediction for each gene. T cell, CD4 naïve cell, and neutrophil levels were significantly higher in the disease group than in the paired normal group, and key gene expression was strongly correlated with immune cells. CMap results showed that the expression profiles of ibuprofen, forskolin, bongkrek-acid, and cimaterol showed the most significant negative correlation with the expression profiles of disease perturbations, suggesting that these drugs may play a role in AS treatment. CONCLUSION: The potential biomarkers of AS screened in this study are closely related to the level of immune cell infiltration and play an important role in the immune microenvironment. This may provide help in the clinical diagnosis and treatment of AS and provide new ideas for further research.

Lin28-mediated temporal promotion of protein synthesis is crucial for neural progenitor cell maintenance and brain development in mice.

Neural progenitor cells (NPCs) undergo rapid proliferation during neurulation. This rapid growth generates a high demand for mRNA translation in a timing-dependent manner, but its underlying mechanism remains poorly understood. Lin28 is an RNA-binding protein with two paralogs, Lin28a and Lin28b, in mammals. Mice with Lin28b deletion exhibit no developmental defects, whereas we have previously reported that Lin28a deletion leads to microcephaly. Here, we find that Lin28a/b double knockout (dKO) mice display neural tube defects (NTDs) coupled with reduced proliferation and precocious differentiation of NPCs. Using ribosomal protein 24 hypomorphic mice (Rpl24Bst/+ ) as a genetic tool to dampen global protein synthesis, we found that Lin28a-/-;Rpl24Bst/+ compound mutants exhibited NTDs resembling those seen in Lin28a/b dKO mice. Increased NPC numbers and brain sizes in Lin28a-overexpressing mice were rescued by Rpl24Bst/+ heterozygosity. Mechanistically, polysome profiling revealed reduced translation of genes involved in the regulation of cell cycle, ribosome biogenesis and translation in dKO mutants. Ribosome biogenesis was reduced in dKO and increased in Lin28a-overexpressing NPCs. Therefore, Lin28-mediated promotion of protein synthesis is essential for NPC maintenance and early brain development.

Fecal microbiota as a noninvasive biomarker to predict the tissue iron accumulation in intestine epithelial cells and liver.

Iron is an essential trace mineral required for growth, metabolism, and immune response. Dysregulation of iron homeostasis is linked with the development and progression of various diseases. Iron accumulation is associated with inflammatory diseases and cancer, while iron deficiency leads to the growth retardation. Several studies have suggested that iron imbalance results in alteration of gut microbiota, leading to the disruption of microbial diversity, the increase of pathogen abundance, and the induction of intestinal inflammation. However, in screening studies done in the past decades, the association between the iron availability and gut microbiota has not been systemically explored. Furthermore, a noninvasive and convenient approach to determine the iron levels in tissues is lacking. In the present study, a murine model for iron dysregulation was established. 16S rRNA amplicon sequencing and bioinformatic algorithms were used to identify the key taxa. Using the key taxa identified and machine learning models, we established an easily accessible prediction model, which could accurately distinguish between iron-deprived or iron-fortified condition. This prediction model could precisely predict the iron level of the intestinal epithelial cells and the liver and could be used for early diagnosis of iron dysbiosis-related diseases, in a noninvasive manner, in the future.

Nr4a1 as a myogenic factor is upregulated in satellite cells/myoblast under proliferation and differentiation state.

Myogenic differentiation is precisely regulated with a cascade of genes and pathways. The previous study has demonstrated the muscle-specific deletion of Nr4a1 impairs muscle growth. However, it is still unclear whether muscular Nr4a1 deletion may directly impact myoblast physiology. Here, the present study delves into the molecular mechanism of Nr4a1 in C2C12. Through the analysis of RNAseq and microarray data, Nr4a1 was identified to highly correlate with the expression of myogenic factors. In C2C12, except confirming the induction of Nr4a1 mRNA and protein levels upon the initiation of differentiation, we observed a novel shuttling phenomenon of Nr4a1 from nucleus to cytoplasm in myoblast with a higher expression of MyoD or differentiated myotubes. Furthermore, Nr4a1 overexpression in C2C12 accelerates myoblasts' differentiation and increases myoblast fusion. In contrast, ablation of Nr4a1 expression in C2C12 inhibits the differentiation and fusion process. Meanwhile, in quiescent satellite cells, Nr4a1 expressed is not detected, while its protein level is highly induced in both BaCl2-induced muscle regeneration followed with satellite cells activation and satellite cells of cultured single myofiber. The mechanism may be through the Nr4a1-mediated expression of myogenic factors, e.g. MyoD and MyoG. In summary, the current investigation demonstrates that Nr4a1 is an essential myogenic factor involved in myoblast differentiation.

BAMBI shuttling between cytosol and membrane is required for skeletal muscle development and regeneration.

Bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) gene encodes a transmembrane protein and is involved in multiple physiological and pathological processes, such as inflammatory response, tumor development and progression, cell proliferation and differentiation. A previous study suggested that BAMBI may interact with the Wnt/ß-catenin signaling pathway via promoting ß-catenin nuclear translocation associated with C2C12 myogenic myoblast differentiation. However, its biological function in skeletal muscle still remains unknown and requires further characterization. The present work sought to investigate its biological function in skeletal muscle, especially the physiological roles of BAMBI during skeletal muscle growth and regeneration. Our current work suggests that BAMBI protein is highly expressed in skeletal muscle and is only detected in cytosolic fraction in the resting muscle. Moreover, BAMBI protein is co-localized in fast-twitch (glycolytic) fibers, but not in slow-twitch (oxidative) fibers. Comparing with the cytosolic trapping in resting muscle, BAMBI protein is enriched on cellular membrane during the muscle growth and regeneration, suggesting that BAMBI-mediated a significant signaling pathway may be an essential part of muscle growth and regeneration.

Aeschynomene indica-Nodulating Rhizobia Lacking Nod Factor Synthesis Genes: Diversity and Evolution in Shandong Peninsula, China.

Aeschynomene indica is a semiaquatic legume that forms both stem and root nodules with rhizobia. Some A. indica rhizobia (AIRs) have been reported to nodulate the host using a Nod factor-independent pathway and possess photosynthetic abilities. To investigate the diversity and community structure of AIRs in China, a total of 300 rhizobial isolates were acquired from the root and stem nodules of A. indica grown at 4 sites in Shandong Peninsula, China. Nineteen representative strains were selected according to their recA phylogeny. With further classification in comparison with reference strains, 10 Bradyrhizobium genospecies were defined based on the 16S rRNA gene phylogeny and multilocus sequence analysis (MLSA) of housekeeping genes (HKGs) recA, atpD, glnII, dnaK, gyrB, and rpoB In addition, 6 genospecies were found only in China. No nodulation gene (nodA, nodB, nodC, or nodZ) was detected in the AIRs isolates by PCR amplification and Southern blotting. Phylogenetic analysis of nifH and the photosynthesis-related gene pufLM revealed their common origins. All representative strains formed root nodules, but only 9 representative strains for 4 genospecies formed stem nodules on A. indica, indicating that the stem nodulation process of A. indica is limited to some strains. The nucleotide diversity and recombination events of the HKGs, as well as nifH and pufLM genes, showed that mutation contributes more than recombination in evolution. The distribution of dominant AIR genospecies was mainly affected by available nitrogen, organic carbon, total nitrogen, and pH. Our study helps to characterize the diversity and evolution of AIRs.IMPORTANCEAeschynomene indica rhizobia (AIRs) can form both root and stem nodules via Nod factor-independent processes, which distinguishes them from other rhizobia. This study systematically uncovered the diversity and community composition of A. indica rhizobia distributed in eastern China. Our results reclassified all the A. indica rhizobia across the world and represent a useful contribution to evaluating the diversity and distribution of the symbiont. The presence of novel genospecies specifically distributed in China enriched the A. indica rhizobia resources and provided insight into the geographic distribution of rhizobia. The phylogenetic relationship between nifH and pufLM of A. indica rhizobia across the world provides insight into the evolution of their nitrogen fixation and photosynthetic abilities.

Serum biochemistry, histology and transcriptomic profile analysis reflect liver inflammation and damage following dietary histamine supplementation in yellow catfish (Pelteobagrus fulvidraco).

Previous studies suggested that diets containing high levels of histamine influenced digestive system of aquatic animals. In addition, the exogenous histamine was first detoxified by diamine oxidase in the intestine, while the rest of histamine was further detoxified in the liver. Thus, based on the evidence from the previous studies, we hypothesized that high levels of histamine may lead to damage on liver of the aquatic animals. Here, in current attempt, we sought to investigate the toxic effect of histamine on yellow catfish (Pelteobagrus fulvidraco) liver physiology and pathogenesis. In the present study, yellow catfish were fed for 56 days on diets supplemented with 1000 mg kg-1 histamine (His) or a basal diet as the control group (Con). A significant change on the morphology of the intestine and liver was observed, followed with an induction of serum activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Furthermore, the transcriptomic analysis was performed to gain an overview of the gene expression profile in liver between control and histamine supplemented groups. Through the bioinformatics analysis, 431 differentially expressed genes were identified. Among these genes, Gene Ontology enrichment analysis (GO) suggests that immune-related genes are significantly dysregulated. In addition, TNF signaling pathway is enriched in Kyoto Encyclopedia of Genes and Genomes analysis (KEGG), and is also the dominant pathway in immune system, suggesting that the inflammatory response and apoptosis of hepatocytes are induced by exogenous histamine.

Adsorption of Zn(II) from aqueous solution and separation of zinc isotopes by displacement chromatography using chelating adsorbent.

The removal of zinc ions (Zn(II)) in water and the separation of zinc isotopes were fully investigated in this study. Imidodiacetic acid (IDA) type adsorbent (named PSGI) based on polystyrene spheres (PS) was synthesized by simultaneous irradiation grafting. By adsorption method, the removal of Zn(II) from water by the chelating adsorbent was studied in batch experiments. Under optimized condition, PSGI showed the removal efficiency of more than 98 % for Zn(II) and the adsorption capacity of 70.1 mg/g. Langmuir isothermal and pseudo-second-order kinetic model fitted the experimental results better, indicating that the adsorption is dominated by chemical adsorption. The spent adsorbent (PSGI-Zn) was used for further zinc isotope separation by displacement chromatography using EDTA-NH4 solution as eluent. Due to the mass effect of isotopes, 70Zn was found to preferentially fractionated into the front-end effluents with the highest front enrichment values of 70Zn/64Zn. By extending the migration distance to 20 m, we obtained the best isotope enrichment with the front maximum enrichment values as 1.0949, 1.0739 and separation coefficient values as 1.977 × 10-3, 8.33 × 10-3 corresponding to the isotope pairs 66Zn/64Zn, 68Zn/64Zn.

Excess PrPC inhibits muscle cell differentiation via miRNA-enhanced liquid-liquid phase separation implicated in myopathy.

The cellular prion protein (PrPC) is required for skeletal muscle function. Here, we report that a higher level of PrPC accumulates in the cytoplasm of the skeletal muscle of six myopathy patients compared to controls. PrPC inhibits skeletal muscle cell autophagy, and blocks myoblast differentiation. PrPC selectively binds to a subset of miRNAs during myoblast differentiation, and the colocalization of PrPC and miR-214-3p was observed in the skeletal muscle of six myopathy patients with excessive PrPC. We demonstrate that PrPC is overexpressed in skeletal muscle cells under pathological conditions, inhibits muscle cell differentiation by physically interacting with a subset of miRNAs, and selectively recruits these miRNAs into its phase-separated condensate in living myoblasts, which in turn enhances liquid-liquid phase separation of PrPC, promotes pathological aggregation of PrP, and results in the inhibition of autophagy-related protein 5-dependent autophagy and muscle bundle formation in myopathy patients characterized by incomplete muscle regeneration.

S/O/W microparticles prepared with hydroxyethyl starch-based emulsifier showed reduced macrophage affinity.

The intramuscular administration of long-acting injectable microparticles elicits a local macrophage uptake resulting in decreased bioavailability. Herein, we developed a ginkgolide B (GB) loaded Solid/Oil/Water (S/O/W) solid lipid microparticles (SLMs) which were modified by hydroxyethyl starch (HES) or poly(ethylene glycol) (PEG) with different surface densities to investigate the influence of surface properties on the cellular uptake and systemic drug exposure. The spherical SLMs with a mean particle size of 10 µm were prepared by melt emulsification and post-insertion method, showing controlled release profile with less than 10 % of GB released in first 2 h. HES-SLMs resulted in lowest degree of RAW264.7 macrophage uptake in vitro and a higher systemic drug exposure in rats than PEG coating SLMs, indicting the capability of thick HES layer of SLMs in evading cellular uptake and sustained GB release. Overall, HES modified SLMs possess a great potential as intramuscular injected drug delivery system to improved bioavailability.

Dietary exposure to polystyrene nanoplastics impairs fasting-induced lipolysis in adipose tissue from high-fat diet fed mice.

The health concerns of microplastics (MPs) and nanoplastics (NPs) surge, but the key indicators to evaluate the adverse risks of MPs/NPs are elusive. Recently, MPs/Ps were found to disturb glucose and lipid metabolism in rodents, suggesting that MPs/NPs may play a role in obesity progression. In this study, we firstly demonstrated that the distribution of fluorescent polystyrene nanoplastics (nPS, 60 nm) white adipose tissue (WAT) of mice. Furthermore, nPS could traffic across adipocytes in vitro and reduced lipolysis under ß-adrenergic stimulation in adipocytes in vitro and ex vivo. Consistently, chronic oral exposure to nPS at the dietary exposure relevant concentrations (3 and 223 µg/kg body weight) impaired fasting-induced lipid mobilization in obese mice and subsequently contributed to larger adipocyte size in the subcutaneous WAT. In addition, the chronic exposure of nPS induced macrophage infiltration in the small intestine and increased lipid accumulation in the liver, accelerating the disruption of systemic metabolism. Collectively, our findings highlight the potential obesogenic role of nPS via diminishing lipid mobilization in WAT of obese mice and suggest that lipolysis relevant parameters may be used for evaluating the adverse effect of MPs/NPs in clinics.

EasyMicroPlot: An Efficient and Convenient R Package in Microbiome Downstream Analysis and Visualization for Clinical Study.

Advances in next-generation sequencing (NGS) have revolutionized microbial studies in many fields, especially in clinical investigation. As the second human genome, microbiota has been recognized as a new approach and perspective to understand the biological and pathologic basis of various diseases. However, massive amounts of sequencing data remain a huge challenge to researchers, especially those who are unfamiliar with microbial data analysis. The mathematic algorithm and approaches introduced from another scientific field will bring a bewildering array of computational tools and acquire higher quality of script experience. Moreover, a large cohort research together with extensive meta-data including age, body mass index (BMI), gender, medical results, and others related to subjects also aggravate this situation. Thus, it is necessary to develop an efficient and convenient software for clinical microbiome data analysis. EasyMicroPlot (EMP) package aims to provide an easy-to-use microbial analysis tool based on R platform that accomplishes the core tasks of metagenomic downstream analysis, specially designed by incorporation of popular microbial analysis and visualization used in clinical microbial studies. To illustrate how EMP works, 694 bio-samples from Guangdong Gut Microbiome Project (GGMP) were selected and analyzed with EMP package. Our analysis demonstrated the influence of dietary style on gut microbiota and proved EMP package's powerful ability and excellent convenience to address problems for this field.

Transferrin receptor 1 ablation in satellite cells impedes skeletal muscle regeneration through activation of ferroptosis.

BACKGROUND: Satellite cells (SCs) are critical to skeletal muscle regeneration. Inactivation of SCs is linked to skeletal muscle loss. Transferrin receptor 1 (Tfr1) is associated with muscular dysfunction as muscle-specific deletion of Tfr1 results in growth retardation, metabolic disorder, and lethality, shedding light on the importance of Tfr1 in muscle physiology. However, its physiological function regarding skeletal muscle ageing and regeneration remains unexplored. METHODS: RNA sequencing is applied to skeletal muscles of different ages to identify Tfr1 associated to skeletal muscle ageing. Mice with conditional SC ablation of Tfr1 were generated. Between Tfr1SC/WT and Tfr1SC/KO (n = 6-8 mice per group), cardiotoxin was intramuscularly injected, and transverse abdominal muscle was dissected, weighted, and cryosectioned, followed by immunostaining, haematoxylin and eosin staining, and Masson staining. These phenotypical analyses were followed with functional analysis such as flow cytometry, tread mill, Prussian blue staining, and transmission electron microscopy to identify pathological pathways that contribute to regeneration defects. RESULTS: By comparing gene expression between young (2 weeks old, n = 3) and aged (80 weeks old, n = 3) mice among four types of muscles, we identified that Tfr1 expression is declined in muscles of aged mice (~80% reduction, P < 0.005), so as to its protein level in SCs of aged mice. From in vivo and ex vivo experiments, Tfr1 deletion in SCs results in an irreversible depletion of SCs (~60% reduction, P < 0.005) and cell-autonomous defect in SC proliferation and differentiation, leading to skeletal muscle regeneration impairment, followed by labile iron accumulation, lipogenesis, and decreased Gpx4 and Nrf2 protein levels leading to reactive oxygen species scavenger defects. These abnormal phenomena including iron accumulation, activation of unsaturated fatty acid biosynthesis, and lipid peroxidation are orchestrated with the occurrence of ferroptosis in skeletal muscle. Ferroptosis further exacerbates SC proliferation and skeletal muscle regeneration. Ferrostatin-1, a ferroptosis inhibitor, could not rescue ferroptosis. However, intramuscular administration of lentivirus-expressing Tfr1 could partially reduce labile iron accumulation, decrease lipogenesis, and promote skeletal muscle regeneration. Most importantly, declined Tfr1 but increased Slc39a14 protein level on cellular membrane contributes to labile iron accumulation in skeletal muscle of aged rodents (~80 weeks old), leading to activation of ferroptosis in aged skeletal muscle. This is inhibited by ferrostatin-1 to improve running time (P = 0.0257) and distance (P = 0.0248). CONCLUSIONS: Satellite cell-specific deletion of Tfr1 impairs skeletal muscle regeneration with activation of ferroptosis. This phenomenon is recapitulated in skeletal muscle of aged rodents and human sarcopenia. Our study provides mechanistic information for developing novel therapeutic strategies against muscular ageing and diseases.

Pseudoginsenoside-F11 improves long-term neurological function and promotes neurogenesis after transient cerebral ischemia in mice.

Stroke is the leading cause of long-term motor disability and cognitive impairment beside the acute brain injury. Recently, neurogenesis has become an attractive strategy for the chronic recovery of stroke. Our previous study showed that pseudoginsenoside-F11 (PF11), an ocotillol-type saponin, isolated from leaves of Panax pseudoginseng subsp., exerted neuroprotective effects on stroke by alleviating autophagy/lysosomal defects and repressing calcium overload. The present study investigated whether PF11 improved long-term functional recovery and promoted neurogenesis after ischemic stroke induced by transient middle cerebral artery occlusion (tMCAO) in mice. The data showed that PF11 (16, 32 mg/kg, p.o.) administrated once daily one week before tMCAO significantly reduced brain infarction and brain edema on day 3 after tMCAO. Also, PF11 attenuated the mortality, sensorimotor dysfunction, cognitive impairment and hippocampal atrophy of stroke mice. Moreover, the migration of neuroblasts and the generation of newborn neurons in ipsilateral striatum and dentate gyrus (DG) were significantly enhanced by PF11. In line with this, PF11 prevented the decreased survival rate of newborn neurons on day 42 after tMCAO. In addition, PF11 promoted proliferation and differentiation of neural stem cells in vitro. Furthermore, PF11's pro-neurogenic effect was attributed to its activation of the BDNF/TrkB, which was evidenced by that the pharmacological effects of PF11 was abolished by ANA-12, a specific inhibitor of BDNF receptor. Thus, the present study showed that PF11 could improve long-term neurological impairment and promote neurogenesis after stroke possibly through activating BDNF/TrkB pathway, indicating its potential role on treating ischemic stroke, especially chronic recovery.

Transferrin Receptor 1 Regulates Thermogenic Capacity and Cell Fate in Brown/Beige Adipocytes.

Iron homeostasis is essential for maintaining cellular function in a wide range of cell types. However, whether iron affects the thermogenic properties of adipocytes is currently unknown. Using integrative analyses of multi-omics data, transferrin receptor 1 (Tfr1) is identified as a candidate for regulating thermogenesis in beige adipocytes. Furthermore, it is shown that mice lacking Tfr1 specifically in adipocytes have impaired thermogenesis, increased insulin resistance, and low-grade inflammation accompanied by iron deficiency and mitochondrial dysfunction. Mechanistically, the cold treatment in beige adipocytes selectively stabilizes hypoxia-inducible factor 1-alpha (HIF1α), upregulating the Tfr1 gene, and thermogenic adipocyte-specific Hif1α deletion reduces thermogenic gene expression in beige fat without altering core body temperature. Notably, Tfr1 deficiency in interscapular brown adipose tissue (iBAT) leads to the transdifferentiation of brown preadipocytes into white adipocytes and muscle cells; in contrast, long-term exposure to a low-iron diet fails to phenocopy the transdifferentiation effect found in Tfr1-deficient mice. Moreover, mice lacking transmembrane serine protease 6 (Tmprss6) develop iron deficiency in both inguinal white adipose tissue (iWAT) and iBAT, and have impaired cold-induced beige adipocyte formation and brown fat thermogenesis. Taken together, these findings indicate that Tfr1 plays an essential role in thermogenic adipocytes via both iron-dependent and iron-independent mechanisms.

Towards the real-time monitoring of glucose in tear fluid: holographic glucose sensors with reduced interference from lactate and pH.

Glucose-selective holographic sensors were fabricated from unique tetrahedral 2-acrylamidophenylboronic acid (2-APB) incorporated with co-monomers poly(ethylene glycol) acrylate (PEG), (3-acrylamidopropyl)trimethylammonium chloride (ATMA) and [2-(acryloyloxy)ethyl]-trimethylammonium chloride (AETA) into thin hydrogel films which were transformed into volume holograms using a diffusion method coupled with holographic recording using a frequency-doubled Nd:YAG laser (532 nm). The results showed that the 2-APB-based holographic sensors contracted upon addition of glucose due to the formation of a 2:1 complex between the tetrahedral 2-APB and glucose. More significantly, the 2-APB-based holographic sensors had greatly reduced lactate dependence and a hugely reduced pH effect over the physiological range of pH. These features are vital for development of contact lens-based glucose sensor, where the pH variability is greater (pH 5.8-7.8) and the lactate concentration is substantially higher than in blood. Furthermore, the 2-APB-based holographic sensors also displayed fast response to glucose. The successful union of holograms and the tetrahedral 2-APB receptor for glucose detection in artificial tear fluid is also demonstrated. This new type of holographic sensors responding to glucose with features of minor pH effect and negligible interference from lactate is applicable to the detection of glucose concentrations in tear fluid for the management of diabetes.

Long noncoding RNA MALAT1 promotes cell proliferation through suppressing miR-205 and promoting SMAD4 expression in osteosarcoma.

Increasing evidences have indicated that long non-coding RNAs (lncRNAs) play an important role in multiply biological processes including cell development, differentiation, proliferation and invasion. The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), is a highly conserved nuclear ncRNA and a key regulator of metastasis development in several cancers. However, its role in osteosarcoma progression is not well known. In this study, we sought to determine the clinical and bilogical role of MALAT1 in osteosarcoma progression. RT-qPCR analysis showed that MALAT1 expression was significantly increased in primary osteosarcoma tissues and cell lines. Kaplan-Meier analysis indicated that patients with high expression of MALAT1 was associated with poor overall survival compared with the low expressing patients. Furthermore, the gain and loss function assay showed that miR-205 was suppressed by MALAT1 in osteosarcoma and this interaction between miR-205 and MALAT1 has reciprocal effects. Cell viability assay showed that MALAT1 promoted MG-63 and SAOS-2 cell growth through suppressing miR-205. Subsequently, the downstream gene SMAD4 was identified as a direct functional target of miR-205, and miR-205 suppressed osteosarcoma cell growth through suppressing SMAD4. Finally, we demonstrated that MALAT1 promoted osteosarcoma progression via a miR-205-SMAD4 axis. In conclusion, we revealed that enhanced MALAT1 expression predicted unfavourable outcome in osteosarcoma and promoted cell proliferation through suppressing miR-205 and activating SMAD4 function. Thus, lncRNA MALAT1 may serve as a promising prognostic and therapeutic target for osteosarcoma patients.

MALAT1 predicts poor survival in osteosarcoma patients and promotes cell metastasis through associating with EZH2.

Osteosarcoma is the most common type of bone cancer, especially in children and young adults. Recently, long noncoding RNAs (lncRNAs) have emerged as new prognostic markers and gene regulators in several cancers, including osteosarcoma. In this study, we investigated the contributions of the lncRNA MALAT1 in osteosarcoma with a specific focus on its transcriptional regulation and its interaction with EZH2. Our results showed that MALAT1 was significantly increased in osteosarcoma specimens and cell lines. ROC curve analysis showed that MALAT1 had a higher area under the curve than alkaline phosphatase, and Kaplan-Meier survival analysis indicated that patients with high serum levels of MALAT1 showed reduced survival rate. Knockdown of MALAT1 decreased osteosarcoma cell invasion and promoted E-cadherin expression. Mechanistic investigations showed that MALAT1 was transcriptionally activated by TGF-ß. Additionally, EZH2 is highly expressed and associated with the 3' end region of lncRNA MALAT1 in osteosarcoma, and this association finally suppressed the expression of E-cadherin. Subsequently, our gain and loss function assay showed that MALAT1 overexpression promoted cell metastasis and decreased E-cadherin level, however, this effect was partially reversed by EZH2 knockdown. In conclusion, our work illuminates that lncRNA MALAT1 is a potential diagnostic and prognostic factor in osteosarcoma and further demonstrates how MALAT1 confers an oncogenic function. Thus, lncRNA MALAT1 may serve as a promising prognostic and therapeutic target for osteosarcoma patients.

Fifty top-cited classic papers in orthopedic elbow surgery: A bibliometric analysis.

OBJECTIVE: The number of citations that a paper has received reflects the impact of the article within a particular medical area. Citation analysis concerning the most cited articles have been widely reported in orthopedic surgery and its subspecialties. However, which articles are cited most frequently in orthopedic elbow surgery is unknown. This study aimed to identify and analyze the characteristics of the 50 most cited articles in elbow surgery. METHODS: Science Citation Index Expanded was used to search for citations in 181 journals chosen according to the relevance for elbow publications. The 50 most cited articles in elbow surgery were identified. The title, authors, year of publications, article type, journal source, country, institution, number of citations, decade published, citation density and level of evidence were recorded and analyzed. RESULTS: The 50 most cited articles were published between 1950 and 2010. The 1980s was the most productive decade. The number of citations ranged from 388 to 124. All the articles were written in English and published in nine journals. The majority of articles originated from United States, followed by Canada and United Kingdom. Fracture was the most discussed topic. The majority of the top cited articles were clinical studies, with the remaining basic research. The most common level of evidence was level IV. CONCLUSIONS: Identification of the most cited papers in elbow surgery shows an insight into the historical development of elbow surgery and provides the foundation for further investigations.

A primary survey on bryophyte species reveals two novel classes of nucleotide-binding site (NBS) genes.

Due to their potential roles in pathogen defense, genes encoding nucleotide-binding site (NBS) domain have been particularly surveyed in many angiosperm genomes. Two typical classes were found: one is the TIR-NBS-LRR (TNL) class and the other is the CC-NBS-LRR (CNL) class. It is seldom known, however, what kind of NBS-encoding genes are mainly present in other plant groups, especially the most ancient groups of land plants, that is, bryophytes. To fill this gap of knowledge, in this study, we mainly focused on two bryophyte species: the moss Physcomitrella patens and the liverwort Marchantia polymorpha, to survey their NBS-encoding genes. Surprisingly, two novel classes of NBS-encoding genes were discovered. The first novel class is identified from the P. patens genome and a typical member of this class has a protein kinase (PK) domain at the N-terminus and a LRR domain at the C-terminus, forming a complete structure of PK-NBS-LRR (PNL), reminiscent of TNL and CNL classes in angiosperms. The second class is found from the liverwort genome and a typical member of this class possesses an α/ß-hydrolase domain at the N-terminus and also a LRR domain at the C-terminus (Hydrolase-NBS-LRR, HNL). Analysis on intron positions and phases also confirmed the novelty of HNL and PNL classes, as reflected by their specific intron locations or phase characteristics. Phylogenetic analysis covering all four classes of NBS-encoding genes revealed a closer relationship among the HNL, PNL and TNL classes, suggesting the CNL class having a more divergent status from the others. The presence of specific introns highlights the chimerical structures of HNL, PNL and TNL genes, and implies their possible origin via exon-shuffling during the quick lineage separation processes of early land plants.