[Re-understanding the role of enamel matrix proteins in periodontal regeneration].

Enamel matrix proteins (EMP) are deposited on the surface of developing roots before dentin formation and may play a role in osteogenesis. Amelogenins (Am) are the main and active component in EMPs. Studies had showed great clinical values of EMPs in periodontal regenerative treatment and other fields. By affecting the expression of growth factors and inflammatory factors, EMPs could act on various periodontal regeneration-related cells to promote angiogenesis, anti-inflammation, bacteriostasis and tissue healing, achieving the clinical effect of periodontal tissue regeneration (newly generated cements and alveolar bones as well as functionally penetrated periodontal ligament). EMPs alone or combined with bone graft material and barrier can be used for regenerative surgical treatment in intrabony defects and degree Ⅱ furcation-involved at maxillary buccal or mandibular teeth. EMPs can also be adjunctively used to treat recession type 1 or 2 gingival recessions, forming periodontal regeneration on the exposed root surface. Through a comprehensive understanding of the principle and current clinical application of EMPs on periodontal regeneration, we can look forward to their future development. The development of recombinant human amelogenin to replace animal-derived EMPs through bioengineering technologies, the study of the clinical application of EMPs combined with other collagen biomaterials, and the specific application of EMPs in severe soft and hard periodontal tissue defects and peri-implant lesions are all important development directions of future EMPs-related researches.

[Analyzing the relevant factors affecting the clinical outcome of periodontal regeneration surgery].

Periodontitis can lead to periodontal tissue defect, tooth mobility and loss, which seriously affects the quality of life. Periodontal regeneration surgery is an important treatment method for repairing periodontal defects, and it is also the hotspot of current periodontal clinical and basic research. A comprehensive understanding of the factors affecting the efficacy of periodontal regenerative surgery can improve clinicians' periodontal treatment concepts, increases the predictability of treatment results, and enhances the level of clinical diagnosis and periodontal treatment. In order to instruct the clinicians, this article will explain the basic principles of periodontal regeneration and the key points of periodontal wound healing, and analyze the elements of periodontal regeneration surgery, which including the patient-related factors, local factors, surgical factors and regenerative material selection.

The DNA Radical Code. Resolution of Identity in Dissociations of Trinucleotide Codon Cation Radicals in the Gas Phase.

Sixty DNA trinucleotide cation radicals covering a large part of the genetic code alphabet were generated by electron transfer in the gas phase, and their chemistry was studied by collision-induced dissociation tandem mass spectrometry and theoretical calculations. The major dissociations involved loss of nucleobase molecules and radicals, backbone cleavage, and cross-ring fragmentations that depended on the nature and position of the nucleobases. Mass identity in dissociations of symmetrical trinucleotide cation radicals of the (XXX+2H)+• and (XYX+2H)+• type was resolved by specific 15N labeling. The specific features of trinucleotide cation radical dissociations involved the dominant formation of d2+ ions, hydrogen atom migrations accompanying the formation of (w2+H)+•, (w2+2H)+, and (d2+2H)+ sequence ions, and cross-ring cleavages in the 3'- and 5'-deoxyribose moieties that depended on the nucleobase type and its position in the ion. Born-Oppenheimer molecular dynamics (BOMD) and density functional theory calculations were used to obtain structures and energies of several cation-radical protomers and conformers for (AAA+2H)+•, (CCC+2H)+•, (GGG+2H)+•, (ACA+2H)+•, and (CAA+2H)+• that were representative of the different types of backbone dissociations. The ion electronic structure, protonation and radical sites, and hydrogen bonding were used to propose reaction mechanisms for the dissociations.

Resolution of Identity in Gas-Phase Dissociations of Mono- and Diprotonated DNA Trinucleotide Codons by 15N-Labeling and Computational Structure Analysis.

Dissociations of DNA trinucleotide codons as gas-phase singly and doubly protonated ions were studied by tandem mass spectrometry using 15N-labeling to resolve identity in the nucleobase loss and backbone cleavages. The monocations showed different distributions of nucleobase loss from the 5'-, middle, and 3'-positions depending on the nucleobase, favoring cytosine over guanine, adenine, and thymine in an ensemble-averaged 62:27:11:<1 ratio. The distribution for the loss of the 5'-, middle, and 3'-nucleobase was 49:18:33, favoring the 5'-nucleobase, but also depending on its nature. The formation of sequence w2+ ions was unambiguously established for all codon mono- and dications. Structures of low-Gibbs-energy protomers and conformers of dAAA+, dGGG+, dCCC+, dTTT+, dACA+, and dATC+ were established by Born-Oppenheimer molecular dynamics and density functional theory calculations. Monocations containing guanine favored classical structures protonated at guanine N7. Structures containing adenine and cytosine produced classical nucleobase-protonated isomers as well as zwitterions in which two protonated bases were combined with a phosphate anion. Protonation at thymine was disfavored. Low threshold energies for nucleobase loss allowed extensive proton migration to occur prior to dissociation. Loss of the nucleobase from monocations was assisted by neighboring group participation in nucleophilic addition or proton abstraction, as well as allosteric proton migrations remote from the reaction center. The optimized structures of diprotonated isomers for dAAA2+ and dACA2+ revealed combinations of classical and zwitterionic structures. The threshold and transition-state energies for nucleobase-ion loss from dications were low, resulting in facile dissociations involving cytosine, guanine, and adenine.

Noncanonical Isomers of Nucleoside Cation Radicals: An Ab Initio Study of the Dark Matter of DNA Ionization.

Cation radicals of DNA nucleosides, 2'-deoxyadenosine, 2'-deoxyguanosine, 2'-deoxycytidine, and 2'-deoxythymidine, can exist in standard canonical forms or as noncanonical isomers in which the charge is introduced by protonation of the nucleobase, whereas the radical predominantly resides in the deoxyribose moiety. Density functional theory as well as correlated ab initio calculations with coupled clusters (CCSD(T)) that were extrapolated to the complete basis set limit showed that noncanonical nucleoside ion isomers were thermodynamically more stable than their canonical forms in both the gas phase and as water-solvated ions. This indicated the possibility of exothermic conversion of canonical to noncanonical forms. The noncanonical isomers were calculated to have very low adiabatic ion-electron recombination energies (REad) for the lowest-energy isomers 2'-deoxy-(N-3H)adenos-1'-yl (4.74 eV), 2'-deoxy-(N-7H)guanos-1'-yl (4.66 eV), 2'-deoxy-(N-3H)cytid-1'-yl (5.12 eV), and 2'-deoxy-5-methylene-(O-2H)uridine (5.24 eV). These were substantially lower than the REad value calculated for the canonical 2'-deoxyadenosine, 2'-deoxy guanosine, 2'-deoxy cytidine, and 2'-deoxy thymidine cation radicals, which were 7.82, 7.46, 8.14, and 8.20 eV, respectively, for the lowest-energy ion conformers of each type. Charge and spin distributions in noncovalent cation-radical dA⊂dT and dG⊂dC nucleoside pairs and dAT, dCT, dTC, and dGC dinucleotides were analyzed to elucidate the electronic structure of the cation radicals. Born-Oppenheimer molecular dynamics trajectory calculations of the dinucleotides and nucleoside pairs indicated rapid exothermic proton transfer from noncanonical T+· to A in both dAT+· and dA⊂dT+·, leading to charge and radical separation. Noncanonical T+· in dCT+· and dTC+· initiated rapid proton transfer to cytosine, whereas the canonical dCT+· dinucleotide ion retained the cation radical structure without isomerization. No spontaneous proton transfer was found in dGC+· and dG⊂dC+· containing canonical neutral and noncanonical ionized deoxycytidine.

[Preliminary study on the relationship between different blood glucose levels and periodontitis in patients with diabetes mellitus type 2].

Objective: To determine the correlation between the diabetes mellitus control and periodontitis. Methods: This study was a cross-sectional survey using stratified system sampling model design. The target population was the patients with diabetes investigated from May to July 2018 in Huangpu District of Shanghai. In the present study, severe periodontitis was defined as at least at two sites in different quadrants with probing depth (PD)≥6 mm and clinical attachment loss (CAL)≥ 5 mm. Edentulous induced by periodontitis were also classified as severe periodontitis and the others were classified as non-severe periodontitis subjects. Diabetes control levels were divided into the following three groups: poorly controlled group [glycated hemoglobin (HbA1c)>7.5% and fasting blood glucose (FPG)>7.0 mmol/L], well controlled group (6.5%≤HbA1c≤7.5％ or 6.1 mmol/L≤FPG≤7.0 mmol/L) and ideally controlled group (HbA1c<6.5% and FPG<6.1 mmol/L). SPSS 25.0 was used for statistical analysis. Chi square test was used for demographic data and frequency distribution, α=0.05, two-sided test. Ordinal regression model was used for PD and diabetes control status to balance confounding factors (including age, gender, education and smoking status). After matching the propensity scores between severe periodontitis group and non-severe periodontitis group, logistic regression analysis was used to analyze the level of diabetes control and periodontitis. Results: A total of 5 220 adults over the age of 18 with a medical history of diabetes participated in the survey, of which 3 064 subjects with diabetes mellitus type 2 (T2DM) who were given both oral and laboratory examinations and were included in this study. Statistics showed that the prevalence of moderate and severe periodontitis was 10.57% (324/3 064). In the severe periodontitis group, 79.01% (256/324) of the subjects were over 65 years old, 55.56% (180/324) were male, 58.33% (189/324) had lower education level than high school level, and 21.91% (71/324) were smokers, which were significantly higher than those in the non-severe periodontitis group (P<0.01). In different T2DM status groups, the percentage of severe periodontitis increased with the aggravation of T2DM status. In severe periodontitis group, the proportion of patients with poor glycemic control was higher. T2DM patients with poor glycemic control accounted for 68.52% (222/324) in severe periodontitis group, which was significantly higher than the proportion of non-severe periodontitis group of 60.99% (1 671/2 740) (P<0.05). The regression coefficient of PD was 0.191, and PD had a significant negative effect on the level of blood glucose (P<0.01). There was a significant positive correlation between diabetes glycemic control and severe periodontitis (OR=2.800, P<0.05). Conclusions: In Huangpu District of Shanghai, among T2DM patients, the age of severe periodontitis group was higher than that of non-severe periodontitis group, most of them were male, with lower education level and higher proportion of smoking. The severity of diabetes was related to periodontitis and the proportion of severe periodontitis was higher in patients with poor glycemic control.

Probing d- and l-Adrenaline Binding to ß2-Adrenoreceptor Peptide Motifs by Gas-Phase Photodissociation Cross-Linking and Ion Mobility Mass Spectrometry.

Diazirine-tagged d- and l-adrenaline derivatives formed abundant noncovalent gas-phase ion complexes with peptides N-Ac-SSIVSFY-NH2 (peptide S) and N-Ac-VYILLNWIGY-NH2 (peptide V) upon electrospray ionization. These peptide sequences represent the binding motifs in the ß2-adrenoreceptor. The structures of the gas-phase complexes were investigated by selective laser photodissociation of the diazirine chromophore at 354 nm, which resulted in a loss of N2 and formation of a transient carbene intermediate in the adrenaline ligand without causing its expulsion. The photolyzed complexes were analyzed by collision-induced dissociation (CID-MS3 and CID-MS4) in an attempt to detect cross-links and establish the binding sites. However, no cross-linking was detected in the complexes regardless of the peptide and d- or l-configuration in adrenaline. Cyclic ion mobility measurements were used to obtain collision cross sections (CCS) in N2 for the peptide S complexes. These showed identical values, 334 ± 0.9 Å2, for complexes of the l- and d-adrenaline derivatives, respectively. Identical CCS were also obtained for peptide S complexes with natural l- and d-adrenaline, 317 ± 1.2 Å2, respectively. Born-Oppenheimer molecular dynamics (BOMD) in combination with full geometry optimization by density functional theory calculations provided structures for the complexes that were used to calculate theoretical CCS with the ion trajectory method. A close match (337 Å2) was found for a single low Gibbs energy structure that displayed a binding pocket with Ser 2 and Ser 5 residues forming hydrogen bonds to the adrenaline catechol hydroxyls. Analysis of the BOMD trajectories revealed a small number of contacts between the incipient carbene carbon atom in the ligand and X-H bonds in the peptide, which was consistent with the lack of cross-linking. Temperature dependence of the internal dynamics of peptide S-adrenaline complexes as well as the specifics of the adrenaline carbene reactions are discussed. In particular, peptide amide hydrogen transfer to the carbene carbon atom was calculated to require crossing a potential energy barrier, which may hamper cross-linking in competition with carbene internal rearrangements.

Cation Radicals of Hachimoji Nucleobases P and Z: Generation in the Gas Phase and Characterization by UV-Vis Photodissociation Action Spectroscopy and Theory.

We report the generation of gas-phase cation radicals of unusual nucleobases 5-aza-7-deazaguanine (P) and 6-amino-5-nitro-(1H)pyrid-2-one (Z) that have been used as building blocks of base-expanded (hachimoji) DNA. The cation radicals were generated by collision-induced intramolecular electron transfer and dissociation of ternary copper-terpyridine complexes. The cation radicals were characterized by deuterium labeling and tandem mass spectrometry including MS3 collision-induced dissociation, UV-vis photodissociation, and action spectroscopy. Vibronic absorption UV-vis spectra were calculated by time-dependent density functional theory (TD-DFT) and compared with the action spectra to unequivocally assign the most closely matching structures for the gas-phase cation radicals. Ab initio calculations up to the coupled clusters-complete basis set (CCSD(T)/CBS) level of theory were used to rank by energy the P and Z neutral molecules and cation-radical isomers and provided transition-state and dissociation energies. The 5-aza-7-deazaguanine cation radicals were determined to have the canonical N-1-H, 6-oxo structure (P1+•) that was the global energy minimum within this group of isomers. The Z cation radicals were found to have the 1H-pyrid-2-one structure (Z1+•). The formation of P1+• and Z1+• was shown to be controlled by the solution thermodynamics of the Cu-terpyridine complexes and the kinetics of their dissociations. We also report and compare CCSD(T)/CBS-calculated adiabatic recombination energies of cation radicals for the entire hachimoji set of eight nucleobases, P+• (7.92 eV), Z+• (8.51 eV), S+• (8.51 eV), B+• (7.76 eV), T+• (8.98 eV), C+• (8.62 eV), A+• (8.32 eV), and G+• (7.97 eV), to assess the thermodynamics of base-to-base electron transfer following random ionization.

The Elusive Noncanonical Isomers of Ionized 9-Methyladenine and 2'-Deoxyadenosine.

Noncanonical nucleobases and nucleosides represent newly discovered species of relevance for DNA ionization. We report a targeted synthesis of gas-phase 9-methylene(1H)adenine cation radical (2+·) as a low-energy isomer of ionized 9-methyladenine. Ion 2+· showed unique collision-induced dissociation and UV-vis photodissociation action spectra that distinguished it from other cation radical isomers. Ab initio energy calculations with coupled cluster theory extrapolated to the complete basis set limit, CCSD(T)/CBS, identified cation radical 2+· as the global energy minimum of the adenine-related C6H7N5+· isomers. The action spectrum of 2+· was assigned on the basis of vibronic absorption spectra that were calculated with time-dependent density functional theory for multiple vibrational configurations of thermal ions. The major dissociation of 2+· proceeded by hydrogen loss that was elucidated by deuterium labeling at the exchangeable N-1 and NH2 positions and C-8 position and by kinetic analysis. The dissociation involved a reversible rearrangement to intermediate dihydropteridine structures, yielding a protonated aminopteridine as the product, which was identified by multistep UV-vis action spectroscopy. We also report a computational study of related noncanonical isomers of 2'-deoxyadenosine cation radical having the radical defect at C-1' that were found to be thermodynamically more stable than the canonical isomer in both the gas phase and aqueous solution. The noncanonical isomers were calculated to have extremely low ion-electron recombination energies of 4.42-5.10 eV that would make them dead-end hole traps if produced by DNA ionization.

Cation Radicals of Hachimoji Nucleobases. Canonical Purine and Noncanonical Pyrimidine Forms Generated in the Gas Phase and Characterized by UV-Vis Photodissociation Action Spectroscopy.

Oxidation of nontraditional nucleobases 1-methylcytosine (hachimoji base S) and isoguanine (hachimoji base B) in gas-phase ternary complexes with CuII(terpyridine)2+ formed cation radicals that were characterized by tandem mass spectrometry, UV-vis photodissociation action spectroscopy in the 210-700 nm region, and ab initio calculations up to the CCSD(T)/complete basis set level of theory. Oxidation of S was accompanied by exothermic isomerization in the 1-methylcytosine ion (1+•), forming 1-methylene-2-hydroxy-4-aminopyrimidine cation radical (9+•) as a noncanonical distonic isomer of the nucleobase. Ion 9+• was characterized by deuterium exchange experiments and provided a matching UV-vis action spectrum with the vibronic absorption spectrum from time-dependent density functional theory calculations. Oxidation of B resulted in the formation of a canonical isoguanine cation radical (12+•) as judged from the match of the experimental action spectrum with the calculated vibronic absorption spectrum. The calculated adiabatic ionization energies of canonical S and B, 8.51 and 7.76 eV, respectively, indicated exothermic electron transfer from B to S+• to proceed in an ionized base pair. Contrasting this, the lowest energy tautomer of ionized S (9+•) had a low adiabatic recombination energy, REadiab = 5.70 eV, that would prevent it from oxidizing other nucleobases. Recombination energies of several nucleobase tautomers are reported and discussed.

[Orthodontic treatment and periodontal soft tissue augmentation].

During the orthodontic treatment, if the root moves lingually, the risk of buccal gingival recession is low. On the contrary, if the root moves buccally, the thin buccal bone probably leads to the buccal gingival recession. In patient without gingival recession, bony dehiscence and fenestration make the situation complicated. Both of the directions show high risk of gingival recession. The present article, from the point of view of periodontal soft tissue, introduces the periodontal soft tissue augmentation technique related to orthodontic treatment and the timing of the surgery.

Guanine-adenine interactions in DNA tetranucleotide cation radicals revealed by UV/vis photodissociation action spectroscopy and theory.

Hydrogen-rich cation radicals (GATT + 2H)+˙ and (AGTT + 2H)+˙ represent oligonucleotide models of charged hydrogen atom adducts to DNA. These tetranucleotide cation radicals were generated in the gas phase by one-electron reduction of the respective (GATT + 2H)2+ and (AGTT + 2H)2+ dications in which the charging protons were placed on the guanine and adenine nucleobases. We used wavelength-dependent UV/Vis photodissociation in the valence-electron excitation region of 210-700 nm to produce action spectra of (GATT + 2H)+˙ and (AGTT + 2H)+˙ that showed radical-associated absorption bands in the near-UV (330 nm) and visible (400-440 nm) regions. Born-Oppenheimer molecular dynamics and density-functional theory calculations were used to obtain and rank by energy multiple (GATT + 2H) dication and cation-radical structures. Time-dependent density functional theory (TD-DFT) calculations of excited-state energies and electronic transitions in (GATT + 2H)+˙ were augmented by vibronic spectra calculations at 310 K for selected low-energy cation radicals to provide a match with the action spectrum. The stable product of one-electron reduction was identified as having a 7,8-dihydroguanine cation radical moiety, formed by intramolecular hydrogen atom migration from adenine N-1-H. The hydrogen migration was calculated to have a transition state with a low activation energy, Ea = 96.5 kJ mol-1, and positive activation entropy, ΔS‡ = 75 J mol-1 K-1. This allowed for a fast isomerization of the primary reduction products on the ion-trap time scale of 150 ms that was substantially accelerated by highly exothermic electron transfer.

UV-vis Photodissociation Action Spectroscopy Reveals Cytosine-Guanine Hydrogen Transfer in DNA Tetranucleotide Cation Radicals upon One-Electron Reduction.

We report the generation and spectroscopic study of hydrogen-rich DNA tetranucleotide cation radicals (GATC+2H)+• and (AGTC+2H)+•. The radicals were generated in the gas phase by one-electron reduction of the respective dications (GATC+2H)2+ and (AGTC+2H)2+ and characterized by collision-induced dissociation and photodissociation tandem mass spectrometry and UV-vis photodissociation action spectroscopy. Among several absorption bands observed for (GATC+2H)+•, the bands at 340 and 450 nm were assigned to radical chromophores. Time-dependent density functional theory calculations including vibronic transitions in the visible region of the spectrum were used to provide theoretical absorption spectra of several low-energy tetranucleotide tautomers having cytosine-, adenine-, and thymine-based radical chromophores that did not match the experimental spectrum. Instead, the calculations indicated the formation of a new isomer with the 7,8-H-dihydroguanine cation radical moiety. The isomerization involved hydrogen migration from the cytosine N-3-H radical to the C-8 position in N-7-protonated guanine that was calculated to be 87 kJ mol-1 exothermic and had a low-energy transition state. Although the hydrogen migration was facilitated by the spatial proximity of the guanine and cytosine bases in the low-energy (GATC+2H)+• intermediate formed by electron transfer, the reaction was calculated to have a large negative activation entropy. Rice-Ramsperger-Kassel-Marcus (RRKM) and transition state theory kinetic analysis indicated that the isomerization occurred rapidly in hot cation radicals produced by electron transfer with the population-weighed rate constant of k = 8.9 × 103 s-1. The isomerization was calculated to be too slow to proceed on the experimental time scale in thermal cation radicals at 310 K.

Ground and Excited States of Gas-Phase DNA Nucleobase Cation-Radicals. A UV-vis Photodisociation Action Spectroscopy and Computational Study of Adenine and 9-Methyladenine.

Cation radicals of adenine (A•+) and 9-methyladenine (MA•+) were generated in the gas phase by collision-induced intramolecular electron transfer in copper-terpyridine-nucleobase ternary complexes and characterized by collision-induced dissociation (CID) mass spectra and UV-vis photodissociation action spectroscopy in the 210-700 nm wavelength region. The action spectra of both A•+ and MA•+ displayed characteristic absorption bands in the near-UV and visible regions. Another tautomer of A•+ was generated as a minor product by multistep CID of protonated 9-(2-bromoethyl)adenine. Structure analysis by density functional theory and coupled-clusters ab initio calculations pointed to the canonical 9-H-tautomer Ad1•+ as the global energy minimum of adenine cation radicals. The canonical tautomer MA1•+ was also calculated to be a low-energy structure among methyladenine cation radicals. However, two new noncanonical tautomers were found to be energetically comparable to MA1•+. Vibronic absorption spectra were calculated for several tautomers of A•+ and MA•+ and benchmarked on equation-of-motion coupled-clusters excited-state calculations. Analysis of the vibronic absorption spectra of A•+ tautomers pointed to the canonical tautomer Ad1•+ as providing the best match with the action spectrum. Likewise, the canonical tautomer MA1•+ was the unequivocal best match for the MA•+ ion generated in the gas phase. According to potential-energy mapping, MA1•+ was separated from energetically favorable noncanonical cation radicals by a high-energy barrier that was calculated to be above the dissociation threshold for loss of a methyl hydrogen atom, thus preventing isomerization. Structures and energetics of all four DNA nucleobase cation radicals are compared and discussed.

FBXO17 promotes malignant progression of hepatocellular carcinoma by activating wnt/ß-catenin pathway.

OBJECTIVE: This study was to investigate the expression of FBXO17 in hepatocellular carcinoma (HCC) and its relationship with clinical HCC features and patient prognosis. PATIENTS AND METHODS: The expression of FBXO17 at mRNA level and protein level in tumor tissues and paracancerous tissues of 45 patients with HCC was respectively detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot. Besides, FBXO17 expression and its pathological characteristics of HCC, as well as the prognosis of patients, were also analyzed. Then, the expression level of FBXO17 in HCC cell lines was further verified using qRT-PCR assay. In addition, FBXO17 overexpression and knockdown models were constructed using lentivirus in HCC cell lines including Bel-7402 and HepG2. Cell counting kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EDU), cell clone experiment, flow cytometry, and transwell assay were used to explore the effect of FBXO17 on the biological function of HCC cells. Finally, whether FBXO17 could exert its biological characteristics through wnt/ß-catenin pathway was determined. RESULTS: Results showed that FBXO17 expression in tumor tissues of HCC patients was markedly higher than that in adjacent tissues. Meanwhile, compared with patients with low FBXO17 expression, the pathological grade was higher and the overall survival rate was lower in patients with high expressed FBXO17. In vitro experiments showed that the cell proliferation and metastasis ability in the Anti-FBXO17 group was markedly decreased, and the apoptosis was significantly enhanced compared with the NC group. In contrast, overexpression of FBXO17 markedly increased cell proliferation and metastasis ability while decreased cell apoptosis. Finally, Western blot results indicated that silencing FBXO17 might function through downregulating the expression of proteins in wnt/ß-catenin pathway such as c-Myc, MMP-9, and MMP-2 while upregulating GSK-3ß level, thereby promoting the malignant progression of HCC. CONCLUSIONS: FBXO17 was significantly increased in tumor tissues of HCC patients, which was significantly associated with pathological stage and poor prognosis of these patients. In addition, FBXO17 might promote the malignant progression of HCC by inhibiting wnt/ß-catenin pathway.

Non-covalent complexes of the peptide fragment Gly-Asn-Asn-Gln-Gln-Asn-Tyr in the gas-phase. Photodissociative cross-linking, Born-Oppenheimer molecular dynamics, and ab initio computational binding study.

Non-covalent complexes of the short amyloid peptide motif Gly-Asn-Asn-Gln-Gln-Asn-Tyr (GNNQQNY) with peptide counterparts that were tagged with a diazirine ring at the N-termini (*GNNQQNY) were generated as singly charged ions in the gas phase. Specific laser photodissociation (UVPD) of the diazirine tag in the gas-phase complexes at 355 nm generated transient carbene intermediates that underwent covalent cross-linking with the target GNNQQNY peptide. The crosslinking yields ranged between 0.8 and 4.5%, depending on the combinations of peptide C-terminal amides and carboxylates. The covalent complexes were analyzed by collision-induced dissociation tandem mass spectrometry (CID-MS3), providing distributions of cross-links at the target peptide amino acid residues. A general preference for cross-linking at the target peptide Gln-4-Gln-5-Asn-6-Tyr-7 segment was observed. Born-Oppenheimer molecular dynamics calculations were used to obtain 100 ps trajectories for nine lowest free-energy conformers identified by ωB97X-D/6-31+G(d,p) gradient geometry optimizations. The trajectories were analyzed for close contacts between the incipient carbene atom and the X-H bonds in the target peptide. The close-contact analysis pointed to the Gln-5 and Tyr-7 residues as the most likely sites of cross-linking, consistent with the experimental CID-MS3 results. Non-covalent binding in the amide complexes was evaluated by DFT calculations of structures and energies. Although antiparallel arrangements of the GNNQQNY and *GNNQQNY peptides were favored in low-energy gas-phase and solvated complexes, the conformations and peptide-peptide interface surfaces were found to differ from the secondary structure of the dry interface in GNNQQNY motifs of amyloid aggregates.

[Correlation between serum uric acid and risk of new-onset nonalcoholic fatty liver disease: a 5-year observational cohort study].

Objective: To investigate the association between serum uric acid and the risk of new-onset nonalcoholic fatty liver disease(NAFLD). Methods: An observational cohort study was conducted in a hospital for five years. 856 patients without NAFLD who took physical examination in the hospital physical examination center in 2011 were selected as study subjects. According to the baseline level of serum uric acid, subjects were divided into 4 groups (F1, F2, F3, and F4). After 5-years of follow-up, the incidence of NAFLD in each group was observed in 2016.Serum alanine aminotransferase and aspartate aminotransferase, Total cholesterol, High-density lipoprotein cholesterol, Low-density lipoprotein cholesterol, Triglycerides, Fasting blood glucose and Imaging findings were examined. The cumulative incidence rate of NAFLD in each group was compared and the effect of baseline serum uric acid level on new-onset NAFLD was analyzed by Logistic regression. The receiver operating characteristic curve (ROC) was used to analyze the diagnostic value of uric acid level in NAFLD. Results: The cumulative incidence rate of NAFLD was 19.16%, and the cumulative incidence increased with the increase of baseline uric acid. The incidence rates of F1, F2, F3 and F4 were 7.90%, 13.54%, 20.32% and 34.07% respectively. The difference was statistically significant (P < 0.05). The incidence rate of NAFLD in F2, F3 and F4 groups were 1.637 (0.856 ~ 3.344) times, 2.745 (1.345 ~ 5.211) times and 5.465 (2.977 ~ 9.843) times higher than those in F1 group (P < 0.05). The logistic regression analysis showed that the risk of NAFLD increased with the increase of serum uric acid level, and the serum uric acid level was an independent risk factor for NAFLD with a relative risks (RR) value of 1.654. The ROC curve analysis of serum uric acid levels had no diagnostic value for NAFLD. Conclusion: Our study demonstrates that increased serum uric acid level is an independent risk factor for the development of NAFLD and could be used as an investigative indicator to assess the risk.

Enamel matrix proteins regulate hypoxia-induced cellular biobehavior and osteogenic differentiation in human periodontal ligament cells.

Hypoxia is a crucial microenvironment for inflamed periodontal tissue and periodontal wound healing. Enamel matrix proteins (EMPs) potentially can promote the formation of new periodontium. The effects of EMPs on periodontal ligament cells under hypoxia, however, remain unclear. We investigated the effects of EMPs on cellular biobehavior and osteogenic differentiation of human periodontal ligament cells (hPDLCs) under hypoxia. Under cobalt chloride (CoCl2)-induced hypoxia, cellular biobehavior of hPDLCs, including proliferation, attachment, spreading, and migration with or without EMPs, was evaluated by 3-(4, 5-dimethylthiazol- 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT), cell counting, spreading area measurement and wound scratch assay. The osteogenic activity of hPDLCs was assessed using alkaline phosphatase (ALP) and alizarin red S staining (ARS). The expressions of osteogenic genes including runt related transcription factor 2 (Runx2), ALP, osteocalcin (OCN) and collagen type I (Col-I) were detected using real time quantitative PCR, western blot and immunocytochemistry assays. The biobehavior and osteogenic differentiation of hPDLCs were inhibited significantly under hypoxia. EMPs have no effect on cell proliferation under mimicked hypoxia. EMPs partly reversed the inhibitory effects of hypoxia, however, for other cellular biobehavior including attachment, spreading and migration, and markedly up-regulated osteogenic differentiation activities including ALP, mineralization ability and the expressions of osteogenic genes such as Runx2, ALP, osteocalcin, and collagen type I in hPDLCs under hypoxia. EMPs attenuate the hypoxic injury to cellular biobehavior and osteogenic differentiation in hPDLCs under hypoxia.