Nuclear Factor Erythroid 2-Related Factor 2 Deficiency Results in Amplification of the Liver Fat-Lowering Effect of Estrogen.

Transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates multiple biologic processes, including hepatic lipid metabolism. Estrogen exerts actions affecting energy homeostasis, including a liver fat-lowering effect. Increasing evidence indicates the crosstalk between these two molecules. The aim of this study was to evaluate whether Nrf2 modulates estrogen signaling in hepatic lipid metabolism. Nonalcoholic fatty liver disease (NAFLD) was induced in wild-type and Nrf2-null mice fed a high-fat diet and the liver fat-lowering effect of exogenous estrogen was subsequently assessed. We found that exogenous estrogen eliminated 49% and 90% of hepatic triglycerides in wild-type and Nrf2-null mice with NAFLD, respectively. This observation demonstrates that Nrf2 signaling is antagonistic to estrogen signaling in hepatic fat metabolism; thus, Nrf2 absence results in striking amplification of the liver fat-lowering effect of estrogen. In addition, we found the association of trefoil factor 3 and fatty acid binding protein 5 with the liver fat-lowering effect of estrogen. In summary, we identified Nrf2 as a novel and potent inhibitor of estrogen signaling in hepatic lipid metabolism. Our finding may provide a potential strategy to treat NAFLD by dually targeting Nrf2 and estrogen signaling.

Nrf2 is essential for timely M phase entry of replicating hepatocytes during liver regeneration.

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) regulates various cellular activities, including redox balance, detoxification, metabolism, autophagy, proliferation, and apoptosis. Several studies have demonstrated that Nrf2 regulates hepatocyte proliferation during liver regeneration. The aim of this study was to investigate how Nrf2 modulates the cell cycle of replicating hepatocytes in regenerating livers. Wild-type and Nrf2 null mice were subjected to 2/3 partial hepatectomy (PH) and killed at multiple time points for various analyses. Nrf2 null mice exhibited delayed liver regrowth, although the lost liver mass was eventually restored 7 days after PH. Nrf2 deficiency did not affect the number of hepatocytes entering the cell cycle but did delay hepatocyte mitosis. Mechanistically, the lack of Nrf2 resulted in increased mRNA and protein levels of hepatic cyclin A2 when the remaining hepatocytes were replicating in response to PH. Moreover, Nrf2 deficiency in regenerating livers caused dysregulation of Wee1, Cdc2, and cyclin B1 mRNA and protein expression, leading to decreased Cdc2 activity. Thus, Nrf2 is required for timely M phase entry of replicating hepatocytes by ensuring proper regulation of cyclin A2 and the Wee1/Cdc2/cyclin B1 pathway during liver regeneration.

Nrf2 participates in regulating maternal hepatic adaptations to pregnancy.

Pregnancy induces widespread adaptive responses in maternal organ systems including the liver. The maternal liver exhibits significant growth by increasing the number and size of hepatocytes, by largely unknown mechanisms. Nrf2 mediates cellular defense against oxidative stress and inflammation and also regulates liver regeneration. To determine whether Nrf2 is involved in the regulation of maternal hepatic adaptations to pregnancy, we assessed the proliferation and size of maternal hepatocytes and the associated molecular events in wild-type and Nrf2-null mice at various stages of gestation. We found that wild-type maternal hepatocytes underwent proliferation and size reduction during the first half, and size increase without overt replication during the second half, of pregnancy. Although pregnancy decreased Nrf2 activity in the maternal liver, Nrf2 deficiency caused a delay in maternal hepatocyte proliferation, concomitant with dysregulation of the activation of Cyclin D1, E1, and, more significantly, A2. Remarkably, as a result of Nrf2 absence, the maternal hepatocytes were largely prevented from reducing their sizes during the first half of pregnancy, which was associated with an increase in mTOR activation. During the second half of pregnancy, maternal hepatocytes of both genotypes showed continuous volume increase accompanied by persistent activation of mTOR. However, the lack of Nrf2 resulted in dysregulation of the activation of the mTOR upstream regulator AKT1 and the mTOR target p70SK6 and thus disruption of the AKT1/mTOR/p70S6K pathway, which is known to control cell size. This suggests an mTOR-dependent and AKT1- and p70S6K-independent compensatory mechanism when Nrf2 is deficient. In summary, our study demonstrates that Nrf2 is required for normal maternal hepatic adjustments to pregnancy by ensuring proper regulation of the number and size of maternal hepatocytes.

Advances in functional coatings on biliary stents.

Biliary stenting is an important interventional method for the prevention and treatment of biliary tract diseases. However, complications, such as postoperative biliary infection and restenosis, frequently occur due to the extensive scope of the biliary system and the complex composition of bile. The combination of coating technology and biliary stents is expected to bring new approaches to the solution of these problems. The cutting-edge advance on functional coatings on biliary stents is reviewed from seven perspectives: anticorrosion, -bacterial, -tumor, stone-dissolving, X-ray visibility, antistent migration and functional composite coatings. The development trend is also discussed. Overall, the performance of the numerous functional coatings for various purposes is generally up to expectations, but the balance between the medications' effectiveness and their safety needs to be further adjusted. Many contemporary investigations have advanced to the level of animal experiments, offering crucial fundamental assurance for broader human studies. The combination of biliary stents and functional coatings is an innovative idea with great potential for future development.

Copolymers functionalized with quaternary ammonium compounds under template chain exhibit simultaneously efficient bactericidal and flocculation properties: Characterization, performance and mechanism.

In this work, novel multifunctional cationic template copolymers with flocculation and sterilization capabilities were synthesized using a low-pressure ultraviolet (LP-UV) template polymerization method for the removal of kaolin and Escherichia coli (E. coli) from water. The influence of template agents on the structural performance of the copolymers was evaluated through characterization, which showed that template copolymer TPADM possesses a higher cationic charge density and a more complex rough surface, contributing to better flocculation performance than that of the non-template copolymer CPADM. Under optimal experimental conditions, TPADM-1 exhibited removal rates of 98.45% for kaolin and 99% for E. coli (OD600 =0.04), marginally outperforming the non-template copolymer. Simultaneously, TPADM-1 produced good adaptability to kaolin and E. coli wastewater in terms of wide pH, speculating that charge neutralization, adsorption bridging, patching, and sweeping simultaneously dominate the flocculation mechanism. Interestingly, SEM and 3D-EEM analysis confirm that the sterilization of E. coli occurs through two distinct functions: initially adsorption followed by subsequent cell membrane rupture and leakage of cellular contents, ultimately leading to cell death. This research further confirms the feasibility of the designed novel multifunctional copolymers for achieving simultaneous disinfection and turbidity removal, demonstrating practical applicability in real water treatment processes.

Securin acetylation prevents precocious separase activation and premature sister chromatid separation.

Lysine acetylation of non-histone proteins plays crucial roles in many cellular processes. In this study, we examine the role of lysine acetylation during sister chromatid separation in mitosis. We investigate the acetylation of securin at K21 by cell-cycle-dependent acetylome analysis and uncover its role in separase-triggered chromosome segregation during mitosis. Prior to the onset of anaphase, the acetylated securin via TIP60 prevents its degradation by the APC/CCDC20-mediated ubiquitin-proteasome system. This, in turn, restrains precocious activation of separase and premature separation of sister chromatids. Additionally, the acetylation-dependent stability of securin is also enhanced by its dephosphorylation. As anaphase approaches, HDAC1-mediated deacetylation of securin promotes its degradation, allowing released separase to cleave centromeric cohesin. Blocking securin deacetylation leads to longer anaphase duration and errors in chromosome segregation. Thus, this study illustrates the emerging role of securin acetylation dynamics in mitotic progression and genetic stability.

In vitro and in vivo degradation, biocompatibility and bone repair performance of strontium-doped montmorillonite coating on Mg-Ca alloy.

Poor bone growth remains a challenge for degradable bone implants. Montmorillonite and strontium were selected as the carrier and bone growth promoting elements to prepare strontium-doped montmorillonite coating on Mg-Ca alloy. The surface morphology and composition were characterized by SEM, EDS, XPS, FT-IR and XRD. The hydrogen evolution experiment and electrochemical test results showed that the Mg-Ca alloy coated with Sr-MMT coating possessed optimal corrosion resistance performance. Furthermore, in vitro studies on cell activity, ALP activity, and cell morphology confirmed that Sr-MMT coating had satisfactory biocompatibility, which can significantly avail the proliferation, differentiation, and adhesion of osteoblasts. Moreover, the results of the 90-day implantation experiment in rats indicated that, the preparation of Sr-MMT coating effectively advanced the biocompatibility and bone repair performance of Mg-Ca alloy. In addition, The Osteogenic ability of Sr-MMT coating may be due to the combined effect of the precipitation of Si4+ and Sr2+ in Sr-MMT coating and the dissolution of Mg2+ and Ca2+ during the degradation of Mg-Ca alloy. By using coating technology, this study provides a late-model strategy for biodegradable Mg alloys with good corrosion resistance, biocompatibility. This new material will bring more possibilities in bone repair.

Dual roles of CCDC102A in governing centrosome duplication and cohesion.

In animal cells, the dysregulation of centrosome duplication and cohesion maintenance leads to abnormal spindle assembly and chromosomal instability, contributing to developmental disorders and tumorigenesis. However, the molecular mechanisms involved in maintaining accurate centrosome number control and tethering are not fully understood. Here, we identified coiled-coil domain-containing 102A (CCDC102A) as a centrosomal protein exhibiting a barrel-like structure in the proximal regions of parent centrioles, where it prevents centrosome overduplication by restricting interactions between Cep192 and Cep152 on centrosomes, thereby ensuring bipolar spindle formation. Additionally, CCDC102A regulates the centrosome linker by recruiting and binding C-Nap1; it is removed from the centrosome after Nek2A-mediated phosphorylation at the onset of mitosis. Overall, our results indicate that CCDC102A participates in controlling centrosome number and maintaining centrosome cohesion, suggesting that a well-tuned system regulates centrosome structure and function throughout the cell cycle.

Metabolic engineering of Escherichia coli for the production of 5-aminolevulinic acid based on combined metabolic pathway modification and reporter-guided mutant selection (RGMS).

BACKGROUND: 5-Aminolevulinic acid (ALA) recently received much attention due to its potential application in many fields such as medicine, nutrition and agriculture. Metabolic engineering is an efficient strategy to improve microbial production of 5-ALA. RESULTS: In this study, an ALA production strain of Escherichia coli was constructed by rational metabolic engineering and stepwise improvement. A metabolic strategy to produce ALA directly from glucose in this recombinant E. coli via both C4 and C5 pathways was applied herein. The expression of a modified hemARS gene and rational metabolic engineering by gene knockouts significantly improved ALA production from 765.9 to 2056.1 mg/L. Next, we tried to improve ALA production by RGMS-directed evolution of eamA gene. After RGMS, the ALA yield of strain A2-ASK reached 2471.3 mg/L in flask. Then, we aimed to improve the oxidation resistance of cells by overexpressing sodB and katE genes and ALA yield reached 2703.8 mg/L. A final attempt is to replace original promoter of hemB gene in genome with a weaker one to decrease its expression. After 24 h cultivation, a high ALA yield of 19.02 g/L was achieved by 108-ASK in a 5 L fermenter. CONCLUSIONS: These results suggested that an industrially competitive strain can be efficiently developed by metabolic engineering based on combined rational modification and optimization of gene expression.

Proteomic analysis of immediate-early response plasma proteins after 70% and 90% partial hepatectomy.

AIM: Partial hepatectomy (PH) induces robust hepatic regenerative and metabolic responses that are considered to be triggered by humoral factors. The aim of the study was to identify plasma protein factors that potentially trigger or reflect the body's immediate-early responses to liver mass reduction. METHODS: Male C57BL/6 mice were subjected to sham operation, 70% PH or 90% PH. Blood was collected from the inferior vena cava at 20, 60 and 180 min after surgery. RESULTS: Using a label-free quantitative mass spectrometry-based proteomics approach, we identified 399 proteins exhibiting significant changes in plasma expression between any two groups. Of the 399 proteins, 167 proteins had multiple unique sequences and high peptide ID confidence (>90%) and were defined as priority 1 proteins. A group of plasma proteins largely associated with metabolism is enriched after 70% PH. Among the plasma proteins that respond to 90% PH are a dominant group of proteins that are also associated with metabolism and one known cytokine (platelet factor 4). Ninety percent PH and 70% PH induces similar changes in plasma protein profile. CONCLUSION: Our findings enable us to gain insight into the immediate-early response of plasma proteins to liver mass loss. Our data support the notion that increased metabolic demands of the body after massive liver mass loss may function as a sensor that calibrates hepatic regenerative response.

Antibacterial Activity and Biocompatibility of Ag-Montmorillonite/Chitosan Colloidal Dressing in a Skin Infection Rat Model: An In Vitro and In Vivo Study.

(1) Background: Traditional dressings can only superficially cover the wound, they have widespread issues with inadequate bacterial isolation and liquid absorption, and it is simple to inflict secondary wound injury when changing dressings. Therefore, it is crucial for wound healing to develop a new kind of antimicrobial colloidal dressing with good antibacterial, hygroscopic, and biocompatible qualities. (2) Methods: Ag-montmorillonite/chitosan (Ag-MMT/CS) colloid, a new type of antibacterial material, was prepared from two eco-friendly materials-namely, montmorillonite and chitosan-as auxiliary materials, wherein these materials were mixed with the natural metal Ag, which is an antibacterial agent. The optimum preparation technology was explored, and Ag-MMT/CS was characterized. Next, Staphylococcus aureus, which is a common skin infection bacterium, was considered as the experimental strain, and the in vitro antibacterial activity and cytocompatibility of the Ag-MMT/CS colloid were investigated through various experiments. Subsequently, a rat skin infection model was established to explore the in vivo antibacterial effect. (3) Results: In vitro studies revealed that the Ag-MMT/CS colloid had a good antibacterial effect on S. aureus, with an inhibition zone diameter of 18 mm and an antibacterial rate of 99.18%. After co-culture with cells for 24 h and 72 h, the cell survival rates were 88% and 94%, respectively. The cells showed normal growth and proliferation, and no evident dead cells were observed under the laser confocal microscope. After applying the colloid to the rat skin infection model, the Ag-MMT/CS treatment group exhibited faster wound healing and better local exudation and absorption in the wound than the control group, suggesting that the Ag-MMT/CS colloid exhibited a better antibacterial effect on the S. aureus. (4) Conclusions: Ag+, chitosan, and MMT present in the Ag-MMT/CS colloid dressing exert synergistic effects, and it has good antibacterial effects, cytocompatibility, and hygroscopicity, indicating that this colloid has the potential to become a next-generation clinical antibacterial dressing.

In vitro corrosion resistance and dual antibacterial ability of curcumin loaded composite coatings on AZ31 alloy: Effect of amorphous calcium carbonate.

Rapid corrosion and bacterial infection are obstacles to put into use biodegradable magnesium (Mg) alloy as biomedical materials. In this research, an amorphous calcium carbonate (ACC)@curcumin (Cur) loaded poly-methyltrimethoxysilane (PMTMS) coating prepared by self-assembly method on micro-arc oxidation (MAO) coated Mg alloy has been proposed. Scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy are adopted to analyze the morphology and composition of the obtained coatings. The corrosion behaviour of the coatings is estimated by hydrogen evolution and electrochemical tests. The spread plate method without or with 808 nm near-infrared irradiation is applied to evaluate the antimicrobial and photothermal antimicrobial ability of the coatings. Cytotoxicity of the samples is tested by 3-(4,5)-dimethylthiahiazo(-z-y1)-2,5-di- phenytetrazoliumromide (MTT) and live/dead assay culturing with MC3T3-E1 cells. Results show that the MAO/ACC@Cur-PMTMS coating exhibited favourable corrosion resistance, dual antibacterial ability, and good biocompatibility. Cur was employed as an antibacterial agent and photosensitizer for photothermal therapy. The core of ACC significantly improved the loading of Cur and the deposition of hydroxyapatite corrosion products during degradation, which greatly promoted the long-term corrosion resistance and antibacterial activity of Mg alloys as biomedical materials.

Protective effects of tiopronin against high fat diet-induced non-alcoholic steatohepatitis in rats.

AIM: To study the protective effects of tiopronin against high fat diet-induced non-alcoholic steatohepatitis in rats. METHODS: Male Sprague-Dawley rats were given a high-fat diet for 10 weeks. The rats were administered tiopronin (20 mg/kg) or a positive control drug ursodeoxycholic acid (UDCA, 15 mg/kg) via gavage daily from week 5 to week 10. After the rats were sacrificed, serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), free fatty acids (FFA), high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C), and liver homogenate FFA, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) were measured using commercial analysis kits. The expression levels of CYP2E1 mRNA and protein were determined using RT-PCR and immunoblot assays, respectively. RESULTS: Tiopronin significantly lowered both the serum ALT and AST levels, while only the serum ALT level was lowered by UDCA. Tiopronin significantly decreased the serum and liver levels of TG, TC and FFA as well as the serum LDL-C level, and increased the serum HDL-C level, while UDCA decreased the serum and liver TC levels as well as the serum LDL-C level, but did not change the serum levels of TG, FFA and HDL-C. Tiopronin apparently ameliorated the hepatocyte degeneration and the infiltration of inflammatory cells in the livers, but UDCA did not affect the pathological features of the livers. Both tiopronin and UDCA ameliorated the mitochondrial abnormality in the livers. The benefits of tiopronin were associated with increased SOD and GSH-Px activities, and with decreased MDA activity and CYP2E1 expression in the livers. CONCLUSION: Tiopronin exerts protective effects against non-alcoholic steatohepatitis in rats, which may be associated with its antioxidant properties and regulation of lipid metabolism.

In vitro degradation, photo-dynamic and thermal antibacterial activities of Cu-bearing chlorophyllin-induced Ca-P coating on magnesium alloy AZ31.

Surgical failures, caused by postoperative infections of bone implants, are commonly met, which cannot be treated precisely with intravenous antibiotics. Photothermal therapy (PTT) and photodynamic therapy (PDT) have attracted widespread attention due to their non-invasive antibacterial effects on tissues and no bacterial resistance, which may be an excellent approach to solve infections related to bone implants for biodegradable magnesium alloys. Herein, a sodium copper chlorophyllin (SCC) with a porphyrin ring induced Ca-P coating was prepared on AZ31 magnesium alloy via layer-by-layer (LbL) assembly. The morphology and composition of the samples were characterized through field emission scanning electron microscope (FE-SEM) with affiliated energy dispersive spectrometer (EDS), X-ray diffractometer (XRD), and Fourier infrared spectrometer (FTIR) and X-ray photoelectron spectrometer (XPS) as well. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and hydrogen evolution experiments were employed to evaluate the corrosion behavior of the samples. Atomic absorption spectrophotometer was used to measure Cu elemental content of different immersion periods. Cytocompatibility and antibacterial performance of the coatings were probed using in vitro cytotoxicity tests (MTT assay), live/dead cell staining and plate counting method. The results showed that the obtained (Ca-P/SCC)10 coating exhibited good corrosion resistance, antimicrobial activity (especially under 808 nm irradiation) and biocompatibility. The antibacterial rates for E. coli and S. aureus were 99.9% and 99.8%, respectively; and the photothermal conversion efficiency was as high as 42.1%. Triple antibacterial mechanisms including photodynamic, photothermal reactions and copper-ions release were proposed. This coating exhibited a promising application for biodegradable magnesium alloys.

Effect of adjuvant-induced systemic inflammation in rats on hepatic disposition kinetics of taurocholate.

It has been reported that the adjuvant-induced inflammation could affect drug metabolism in liver. Here we further investigated the effect of inflammation on drug transport in liver using taurocholate as a model drug. The hepatic disposition kinetics of [(3)H]taurocholate in perfused normal and adjuvant-treated rat livers were investigated by the multiple indicator dilution technique and data were analyzed by a previously reported hepatobiliary taurocholate transport model. Real-time RT-PCR was also performed to determine the mRNA expression of liver bile salt transporters in normal and diseased livers. The uptake and biliary excretion of taurocholate were impaired in the adjuvant-treated rats as shown by decreased influx rate constant k(in) (0.65 ± 0.09 vs. 2.12 ± 0.30) and elimination rate constant k(be) (0.09 ± 0.02 vs. 0.17 ± 0.04) compared with control rat group, whereas the efflux rate constant k(out) was greatly increased (0.07 ± 0.02 vs. 0.02 ± 0.01). The changes of mRNA expression of liver bile salt transporters were found in adjuvant-treated rats. Hepatic taurocholate extraction ratio in adjuvant-treated rats (0.86 ± 0.05, n = 6) was significantly reduced compared with 0.93 ± 0.05 (n = 6) in normal rats. Hepatic extraction was well correlated with altered hepatic ATP content (r(2) = 0.90). In conclusion, systemic inflammation greatly affects hepatic ATP content/production and associated transporter activities and causes an impairment of transporter-mediated solute trafficking and pharmacokinetics.

Nitric oxide induced sinusoidal relaxation after a propranolol priming dose in the perfused rat liver reduces propranolol availability on subsequent dosing.

1. The present study sought to explain the mechanism leading to reduced availability of propranolol when given after a priming dose in the single-pass perfused rat liver. 2. Extracellular sucrose space (as a measure of sinusoidal relaxation) in perfused rat liver before and after propranolol or propranolol and N(G)-nitro-L-arginine methyl ester (L-NAME; nitric oxide (NO) synthase inhibitor) treatment were examined. The results showed that propranolol induces sinusoidal relaxation in the perfused liver and this effect could be abolished by NO synthase inhibitor L-NAME. 3. Two bolus injections of propranolol were given to the isolated perfused rat liver and outflow concentration-time profiles of intact propranolol were determined. A two-phase physiologically based organ pharmacokinetic model was applied to estimate hepatocellular influx, efflux, binding, ion-trapping and metabolic elimination pharmacokinetic parameters for propranolol. The recovery of propranolol in the second injection was approximately 54% of that in the first injection. The permeability-surface area product, the binding and the intrinsic clearance all increased significantly after prior exposure of the rat liver to the first bolus of propranolol (P < 0.05). 4. Based on the findings of the present study, we propose that the most likely explanation for the reduced availability of a second propranolol dose (after administration of a priming dose) in the perfused liver is a consequence of the NO-mediated sinusoidal relaxation effect of propranolol, arising from the priming dose. This observation supports the view that the pharmacokinetics of some drugs might be altered by the pharmacodynamic effects of the same drug given earlier in the perfused liver.

Preventive effects of total flavonoids of Litsea coreana leve on hepatic steatosis in rats fed with high fat diet.

AIM OF THE STUDY: To evaluate the protective effects of total flavonoids of Litsea Coreana leve (TFLC) on rat high fat diet-induced hepatic steatosis model. MATERIALS AND METHODS: Rats were given either a high fat diet alone or the same diet plus TFLC for 4 weeks. RESULTS: TFLC improved liver histology with reduced serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as decreased the over accumulation lipids in serum and liver. TFLC increased serum levels of leptin and insulin, while decreased serum TNFalpha level in high fat diet fed rat. Furthermore, TFLC was found increased the expression of peroxisome proliferator-activated receptor alpha (PPARalpha) in high fat diet fed rat liver. These benefits were associated with increased superoxide dismutase (SOD) and decreased malondialdehyde (MDA) in high fat diet fed rat liver. CONCLUSIONS: TFLC exerts protective effects against hepatic steatosis in rats fed with high fat diet possibly through its antioxidant actions, improving the adipocytokines release and increasing the expression of PPARalpha.

CCDC84 Acetylation Oscillation Regulates Centrosome Duplication by Modulating HsSAS-6 Degradation.

In animal cells, centriole number is strictly controlled in order to guarantee faithful cell division and genetic stability, but the mechanism by which the accuracy of centrosome duplication is maintained is not fully understood. Here, we show that CCDC84 constrains centriole number by modulating APC/CCdh1-mediated HsSAS-6 degradation. More importantly, CCDC84 acetylation oscillates throughout the cell cycle, and the acetylation state of CCDC84 at lysine 31 is regulated by the deacetylase SIRT1 and the acetyltransferase NAT10. Deacetylated CCDC84 is responsible for its centrosome targeting, and acetylated CCDC84 promotes HsSAS-6 ubiquitination by enhancing the binding affinity of HsSAS-6 for Cdh1. Our findings shed new light on the function of (de)acetylation in centriole number regulation as well as refine the established centrosome duplication model.

ß­glucan, a dectin­1 ligand, promotes macrophage M1 polarization via NF­κB/autophagy pathway.

Pro­inflammatory (M1) macrophages have key roles in atherogenesis. As ß­glucan has been demonstrated to exert pro­inflammatory effects, the present study examined whether ß­glucan exerts atherogenic effects via converting macrophages into M1 phenotype. The results from reverse transcription­quantitative polymerase chain reaction, flow cytometry, western blotting and transmission electron microscope indicated that M1 macrophage markers inducible nitric oxide synthase and cluster of differentiation 80 were upregulated, dectin­1 (a receptor for ß­glucan) expression and nuclear factor (NF)­κB nuclear translocation were promoted, and autophagy level was inhibited following ß­glucan treatment of macrophages. Additionally, dectin­1 small interfering RNA (siRNA), autophagy inducer rapamycin and NF­κB inhibitor SN50 reversed the effects of ß­glucan on autophagy level and macrophage M1 polarization, suggesting that dectin­1 and NF­κB are upstream of autophagy in ß­glucan­induced macrophage M1 polarization. Notably, simultaneous treatment with dectin­1 siRNA and SN50 exhibited similar effects on ß­glucan­reduced autophagy compared with dectin­1 siRNA treatment alone. These findings demonstrate that dectin­1 may mediate ß­glucan­reduced autophagy through NF­κB in macrophages. Accordingly, results from hematoxylin and eosin staining, western blotting and immunofluorescence staining demonstrated that ß­glucan accelerated the progress of atherosclerosis in apolipoprotein E­deficient mice and modulated expression of dectin­1, beclin­1 and light chain 3II/I in aortas similarly to that observed in macrophages. These results indicate that dectin­1 activation by ß­glucan exerts atherogenic effects via converting macrophages into M1 phenotype in an NF­κB­autophagy­dependent pathway.

Corrosion resistance and antibacterial activity of zinc-loaded montmorillonite coatings on biodegradable magnesium alloy AZ31.

A Zinc-loaded montmorillonite (Zn-MMT) coating was hydrothermally prepared using Zn2+ ion intercalated sodium montmorillonite (Na-MMT) upon magnesium (Mg) alloy AZ31 as bone repairing materials. Biodegradation rate of the Mg-based materials was studied via potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and hydrogen evolution tests. Results revealed that both Na-MMT and Zn-MMT coatings exhibited better corrosion resistance in Dulbecco's modified eagle medium (DMEM) + 10% calf serum (CS) than bare Mg alloy AZ31 counterparts. Hemolysis results demonstrated that hemocompatibility of the Na-MMT and Zn-MMT coatings were 5%, and lower than that of uncoated Mg alloy AZ31 pieces. In vitro MTT tests and live-dead stain of osteoblast cells (MC3T3-E1) indicated a significant improvement in cytocompatibility of both Na-MMT and Zn-MMT coatings. Antibacterial properties of two representative bacterial strains associated with device-related infection, i.e. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), were employed to explore the antibacterial behavior of the coatings. The measured inhibitory zone and bacterial growth rate confirmed that Zn-MMT coatings exhibited higher suppression toward both E. coli and S. aureus than that of Na-MMT coatings. The investigation on antibacterial mechanism through scanning electron microscopy (SEM) and lactate dehydrogenase (LDH) release assay manifested that Zn-MMT coating led to severe breakage of bacterial membrane of E. coli and S. aureus, which resulted in a release of cytoplasmic materials from the bacterial cells. In addition, the good inhibition of Zn-MMT coatings against E. coli and S. aureus might be attributed to the slow but sustainable release of Zn2+ ions (up to 144 h) from the coatings into the culture media. This study provides a novel coating strategy for manufacturing biodegradable Mg alloys with good corrosion resistance, biocompatibility and antibacterial activity for future orthopedic applications. STATEMENT OF SIGNIFICANCE: The significance of the current work is to develop a corrosion-resistant and antibacterial Zn-MMT coating on magnesium alloy AZ31 through a hydrothermal method. The Zn-MMT coating on magnesium alloy AZ31 shows better corrosion resistance, biocompatibility and excellent antibacterial ability than magnesium alloy AZ31. This study provides a novel coating on Mg alloys for future orthopedic applications.