Mechanisms of the development of abnormal metabolic phenotypes among obese population are not yet clear. In this study, we aimed to screen metabolomes of both healthy and subjects with abnormal ...obesity to identify potential metabolic pathways that may regulate the different metabolic characteristics of obesity.
We recruited subjects with body mass index (BMI) over 25 from the weight-loss clinic of a central hospital in Taiwan. Metabolic healthy obesity (MHO) is defined as without having any form of hyperglycemia, hypertension and dyslipidemia, while metabolic abnormal obesity (MAO) is defined as having one or more abnormal metabolic indexes. Serum-based metabolomic profiling using both liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry of 34 MHO and MAO individuals with matching age, sex and BMI was performed. Conditional logistic regression and partial least squares discriminant analysis were applied to identify significant metabolites between the two groups. Pathway enrichment and topology analyses were conducted to evaluate the regulated pathways.
A differential metabolite panel was identified to be significantly differed in MHO and MAO groups, including L-kynurenine, glycerophosphocholine (GPC), glycerol 1-phosphate, glycolic acid, tagatose, methyl palmitate and uric acid. Moreover, several metabolic pathways were relevant in distinguishing MHO from MAO groups, including fatty acid biosynthesis, phenylalanine metabolism, propanoate metabolism, and valine, leucine and isoleucine degradation.
Different metabolomic profiles and metabolic pathways are important for distinguishing between MHO and MAO groups. We have identified and discussed the key metabolites and pathways that may prove important in the regulation of metabolic traits among the obese, which could provide useful clues to study the underlying mechanisms of the development of abnormal metabolic phenotypes.
Aberrant Wnt signaling pathway is a common feature of tumors and also plays important roles in tumor progression and metastasis of many cancer types. Various lines of evidence suggest that genetic ...defects affect Wnt pathway components, as well as epigenetic mechanisms that modulate the suppressors of Wnt pathway in oral squamous cell carcinoma. Recently, the newly discovered microRNAs are important molecular regulators in gene expression through transcription and translation repression. They play fundamental roles in a wide spectrum of biological functions, including cancer. In this review, we aim to accumulate recent research findings on the roles of Wnt/β-catenin signaling and discuss how microRNAs affect Wnt/β-catenin signaling in oral squamous cell carcinoma tumorigenesis. Apparently, investigations into the role of microRNAs with regard to the Wnt pathway in oral squamous cell carcinoma may help in the development of better strategies for tumor treatment.
The ATM protein, encoded by the gene responsible for the human genetic disorder ataxia telangiectasia (A-T), regulates several cellular responses to DNA breaks. ATM shares a phosphoinositide ...3-kinase-related domain with several proteins, some of them protein kinases. A wortmannin-sensitive protein kinase activity was associated with endogenous or recombinant ATM and was abolished by structural ATM mutations. In vitro substrates included the translation repressor PHAS-I and the p53 protein. ATM phosphorylated p53 in vitro on a single residue, serine-15, which is phosphorylated in vivo in response to DNA damage. This activity was markedly enhanced within minutes after treatment of cells with a radiomimetic drug; the total amount of ATM remained unchanged. Various damage-induced responses may be activated by enhancement of the protein kinase activity of ATM.
Activity of the Axl receptor tyrosine kinase is positively correlated with tumor metastasis; however, its detailed role in the mechanism of tumor invasion is still not completely understood. Here, we ...show that Axl enhances the expression of matrix metalloproteinase 9 (MMP-9), required for Axl-mediated invasion both in vitro and in vivo. We found that the highly selective MEK1/2 inhibitors U0126 and PD98059, and the expressed dominant-negative form of extracellular signal-regulated kinase (ERK), completely block Axl-mediated MMP-9 activation. In contrast, the phosphatidylinositol 3-kinase inhibitor LY294002 and wortmannin had little effect on activation. Interestingly, however, the Axl ligand Gas6 is not involved in Axl-mediated MMP-9 activation. Mutation of Glu59Axl and Thr77Axl dramatically reduced Gas6–Axl binding but continued to induce MMP-9 activation. In addition, overexpression of Axl-activated ERK and enhanced nuclear factor-κB (NF-κB) transactivation and brahma-related gene-1 (Brg-1) translocation. Exposure to the NF-κB inhibitor silibinin, which inhibits IκBα kinase activity, or overexpression of the dominant-negative mutant IκB and Brg-1 strikingly inhibited Axl-mediated MMP-9 activation. These data indicate that coordination of ERK signaling and NF-κB and Brg-1 activation are indispensable to regulation of Axl-dependent MMP-9 gene transcription. Together with previous data, our results provide a plausible mechanism for Axl-mediated tumor invasion and establish a functional link between the Axl and MMP-9 signaling pathways.
Summary
Current bibliometric analyses of the evolving trends in research scope category across different time periods using the H‐classics method in implantology are considerably limited. The purpose ...of this study was to identify the classic articles in implantology to analyse bibliometric characteristics and associated factors in implantology for the past four decades. H‐Classics in implantology were identified within four time periods between 1977 and 2016, based on the h‐index from the Scopus® database. For each article, the principal bibliometric parameters of authorship, geographic origin, country origin, and institute origin, collaboration, centralisation, article type, scope of study and other associated factors were analysed in four time periods. A significant increase in mean numbers of authors per H‐Classics was found across time. Both Europe and North America were the most productive region/country and steadily dominated this field in each time period. Collaborations of author, internationally and inter‐institutionally had significantly increased across time. A significant decentralisation in authorships, institutes and journals was noted in past four decades. The journal of Clinical Oral Implant Researches has raised its importance for almost 30 years (1987‐2016). Research on Complications, peri‐implant infection/pathology/therapy had been increasing in production throughout each period. This is the first study to evaluate research trends in implantology in the past 40 years using the H‐classics method, which through analysing via principle bibliometric characteristics reflected a historical perspective on evolutionary mainstream in the field. Prominence of research regarding complications may forecast innovative advancements in future.
Abstract Autophagy is a cellular response against stresses which include the infection of viruses and bacteria. We unravel that Dengue virus-2 (DV2) can trigger autophagic process in various infected ...cell lines demonstrated by GFP-LC3 dot formation and increased LC3-II formation. Autophagosome formation was also observed under the transmission electron microscope. DV2-induced autophagy further enhances the titers of extracellular and intracellular viruses indicating that autophagy can promote viral replication in the infected cells. Moreover, our data show that ATG5 protein is required to execute DV2-induced autophagy. All together, we are the first to demonstrate that DV can activate autophagic machinery that is favorable for viral replication.
Objectives
Chronic periodontitis is a bone destructive inflammatory disease with an adverse impact on general health and suggested underlying factors in common with osteoporosis. A few studies have ...examined the possible relationship between chronic periodontitis and osteoporosis; however, the results remain inconclusive. This longitudinal follow‐up study investigated the possible risk of patients with chronic periodontitis to present osteoporosis by using a population‐based national health insurance data set in Taiwan.
Material and Methods
A random sample consisting of 1 million individuals was collected from Taiwan's national health insurance data set. From the sample, a total of 29 463 patients with newly diagnosed periodontitis from 2002 to 2008 were recruited and compared with a matched cohort of 58 926 patients without periodontitis. All patients were tracked until an osteoporosis diagnosis, or death, until the end of 2011. Associated factors, such as gender, age and comorbidities were examined. Cox proportional‐hazards regression was performed to examine the risk of osteoporosis for patients with or without periodontitis.
Results
Within the 6‐year follow‐up period, the incidence rates of osteoporosis in the periodontitis cohort and comparison group were 2.72 and 1.66 per 1000 person‐years, respectively. Mild, moderate and severe periodontitis were found to have 1.56, 2.09 and 2.08 times the risk of osteoporosis respectively compared to patients without periodontitis. Log‐rank analysis revealed that patients with periodontitis had significantly higher cumulative incidence rates of osteoporosis than the control group (P<.0001).
Conclusion
This study found that patients with periodontitis had a higher risk of being diagnosed with osteoporosis.
The p53 tumor suppressor protein is widely known for its role as a sequence-specific transcription factor that regulates the expression of stress response genes. Here, we report the identification of ...LIMK2, which encodes a kinase that regulates actin dynamics through phosphorylation of cofilin, as a p53 target upregulated by DNA damage. Interestingly, the splice variant LIMK2b, but not LIMK2a, was induced in a p53-dependent manner through an intronic consensus p53-binding site. Depletion of LIMK2b leads to early exit of G2/M arrest after DNA damage, whereas its overexpression prolongs the arrest. These responses are recapitulated by ectopic expression of the active cofilin S3A mutant and the inactive cofilin S3D mutant, respectively, suggesting that LIMK2b may modulate G2/M arrest through cofilin phosphorylation. Furthermore, in support of its potential role as a tumor suppressor, LIMK2b was downregulated in esophageal and thyroid cancers, as well as in a number of established cancer cell lines, and its expression suppresses cancer cell migration. Taken together, our results unveil a novel pathway whereby LIMK2b, acting downstream of p53, ensures proper execution of checkpoint arrest by modulating the dynamics of actin polymerization.
Upon DNA damage, p53 has been shown to be modified at a number of N‐terminal phosphorylation sites including Ser15 and ‐33. Here we show that phosphorylation is induced as well at a novel site, ...Ser20. Phosphorylation at Ser15, ‐20 and ‐33 can occur within minutes of DNA damage. Interestingly, while the DNA‐binding activities of p53 appear to be dispensable, efficient phosphorylation at these three sites requires the tetramerization domain of p53. Substitution of an artificial tetramerization domain for this region also permits phosphorylation at the N‐terminus, suggesting that oligomerization is important for DNA damage‐induced signalling to p53.
Upon DNA damage, the amino terminus of p53 is phosphorylated at a number of serine residues including S20, a site that is particularly important in regulating stability and function of the protein. ...Because no known kinase has been identified that can modify this site, HeLa nuclear extracts were fractionated and S20 phosphorylation was followed. We discovered that a S20 kinase activity copurifies with the human homolog of the Schizosaccharomyces pombe checkpoint kinase, Chk1 (hCHK1). We confirmed that recombinant hCHK1, but not a kinase-defective version of hCHK1, can phosphorylate p53 in vitro at S20. Additional inducible amino- and carboxy-terminal sites in p53 are also phosphorylated by hCHK1, indicating that this is an unusually versatile protein kinase. It is interesting that hCHK1 strongly prefers tetrameric to monomeric p53 in vitro, consistent with our observation that phosphorylation of amino-terminal sites in vivo requires that p53 be oligomeric. Regulation of the levels and activity of hCHK1 in transfected cells is directly correlated with the levels of p53; expression of either a kinase-defective hCHK1 or antisense hCHK1 leads to reduced levels of cotransfected p53, whereas overexpression of wild-type hCHK1 or the kinase domain of hCHK1 results in increased levels of expressed p53 protein. The human homolog of the second S. pombe checkpoint kinase, Cds1 (CHK2/hCds1), phosphorylates tetrameric p53 but not monomeric p53 in vitro at sites similar to those phosphorylated by hCHK1 kinase, suggesting that both checkpoint kinases can play roles in regulating p53 after DNA damage.
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