Mouse Leukemic Monocyte Research Articles

A new isopimarane-type diterpene with anti-inflammatory activity from the Clinacanthus nutans.

A new isopimarane-type diterpene clinacanoid A (1) together with seven known terpenoids (2-8) were obtained from the Clinacanthus nutans. Their structures were elucidated based on extensive spectroscopic analysis (NMR, HR-ESI-MS), and the absolute configuration of 1 was established based on single crystal X-ray diffraction. The inhibitory activity of all the compounds on NO production in lipopolysaccharide-induced (LPS) mouse leukemic monocyte macrophage RAW264.7 cells was evaluated. Among them, compounds 1 and 3 showed potential anti-inflammatory activities, with IC50 values of 13.3 ± 0.3 and 12.4 ± 0.4 μM, respectively.

Microenvironmental Analysis and Control for Local Cells under Confluent Conditions via a Capillary-Based Microfluidic Device.

Sophisticated functions of biological tissues are supported by small biological units of cells that are localized within a region of 100 μm scale. The cells in these units secrete molecules to form their microenvironment to play a vital role in biological functions. Various microfluidic devices have been developed to analyze the microenvironment but were not designed for cells in a culture dish in a confluent condition, a typical setup for cell and tissue cultivation. This study presents a novel glass capillary-based microfluidic device for studying confluent cells in a culture dish. The multiple capillaries allow the device to confine the local flow in 100 μm or smaller scale to form two adjacent regions with different chemical properties; it can simultaneously perform local cell stimulation and collect secreted molecules from the stimulated cells. Cell removal was achieved upon trypsin stimulation from a limited area (3.8 × 10-3 ± 1.0 × 10-3 mm2), which corresponded to 7.6 ± 2.0 cells, using the mouse skeletal myoblast cell line (C2C12 cells) in a confluent condition. Microenvironmental analysis was demonstrated by measuring the secreted tumor necrosis factor alpha (TNF-α) collected from the microenvironment of the stimulated and unstimulated mouse leukemic monocyte cell line (RAW264 cells) to track temporal changes in the TNF-α production. The TNF-α secreted from stimulated cells was approximately four-fold higher than that from unstimulated cells in 90 min. This device enables local cell stimulation and the collection of secreted molecules for cells under confluent conditions, which contributes to the analysis of the cellular microenvironment.

Effect of Echinococcus multilocularis infections on mitochondrial functions of macrophages

To investigate the changes of mitochondrial metabolic functions of macrophages following Echinococcus multilocularis infections, so as to provide insights into the pathogenesis of alveolar echinococcosis. Two groups were assigned according to different treatment methods. In the culture group, mouse leukemic monocyte macrophage RAW264.7 cells were cultured with 2 000 E. multilocularis at a ratio of 500∶1, while RAW264.7 cells in the control group were given no treatment. Then, both the culture and control groups were further divided into the 24 h and 72 h subgroups. Mitochondria were stained with MitoTracker® Deep Red FM and the mean fluorescence intensity of macrophage mitochondria was measured with the Cytation 5 Cell Imaging Multi-Mode Reader. The mitochondrial DNA copy number was quantified using the quantitative real-time PCR (qPCR) assay, and the mitochondrial energy metabolism was monitored using the Seahorse XF assay. In addition, the mitochondrial reactive oxygen species and mitochondrial membrane potential were detected using flow cytometry. The mean fluorescence intensities of macrophage mitochondria were significantly lower in the 24 h (15 341 ± 2 532 vs. 17 823 ± 3 429; t = 6.379, P < 0.01) and 72 h (18 102 ± 3 505 vs. 21 511 ± 5 144; t = 17.680, P < 0.01) culture subgroups than in the corresponding control subgroups, and lower mitochondrial DNA copy numbers were measured in the 72 h culture subgroup than in the 72 h control group [(3.23 × 109 ± 1.78 × 107) vs. (4.39 × 109 ± 3.70 × 107); t = 8.85, P < 0.001]. The oxygen consumption rates were significantly greater in the 24 h [(241.70 ± 73.13) pmol/min vs. (69.05 ± 52.30) pmol/min; t = 7.89, P < 0.01] and 48 h culture groups [(249.50 ± 42.06) pmol/min vs. (60.28 ± 40.66) pmol/min; t = 8.64, P < 0.01] than in the corresponding control groups, and a higher extracellular acidification rate was seen in the 48 h culture group than in the 48 h control group ([ 111.6 ± 17.49) mpH/min vs. (35.05 ± 7.57) mpH/min; t = 16.90, P < 0.01]. In addition, flow cytometry detected higher mean fluorescence intensity of mitochondrial reactive oxygen species (58 264 ± 10 087 vs. 4 307 ± 97; t = 12.930, P < 0.01) and lower mitochondrial membrane potential (9.833% ± 2.285% vs. 2.667% ± 0.208%; t = 6.645, P < 0.01) in the 72 h culture group than in the control group. E. multilocularis infection may impair mitochondrial functions and inhibit oxidative phosphorylation of macrophages, resulting in increased macrophage glycolysis. It is speculated that the alteration of macrophage metabolic states may contribute to the mechanisms underlying the development and progression of alveolar echinococcosis.

Hepatitis B-surface antigen (HBsAg) vaccine fabricated chitosan-polyethylene glycol nanocomposite (HBsAg-CS-PEG- NC) preparation, immunogenicity, controlled release pattern, biocompatibility or non-target toxicity

Antigen delivery framework utilising polymer-based nanomaterial is broadly used in biomedicine because of their high efficacy, antigenicity and biocompatibility. In this study, hepatitis B surface antigen fabricated chitosan-polyethylene glycol nanocomposite (HBsAg-CS-PEG NC) was prepared by in situ ionic gelation method which brought about highly stable nanoformulation that was characterised by electron microscopy, atomic force microscopy (AFM) Fourier transform infrared spectroscopy (FTIR). Particles morphology by electron microscopy studies reveals spherical, electron-dense, nanostructure with 100–120 nm. AFM studies show a uniform distribution of particles with distinct roughness. Specific interaction of polymers with the vaccine or surface modification and functionalization were confirmed by FTIR analysis. Synthesised nanocomposite exhibited high antigen loading and entrapment efficiency. Release profile study carried out under in vitro condition indicates that a gradual increase in release at increasing time intervals which confirms noteworthy stability and release pattern. Enhanced immunogenicity of the nanocomposite was determined by induction of rosette formation and rate of phagocytosis using T cell rosette formation assay (TCRF assay) and mouse leukemic monocyte macrophage phagocytosis assay. Notable enhancement on rosette formation and phagocytosis percentage was recorded in nanocomposite treatment as dose-dependent manner. Biocompatibility or non-target effect was done by evaluating acute or subacute toxicity against Wistar rat model and hemocompatibility. Hemocompatibility was measured by determination of hemolysis, antioxidative enzymes, erythrocytes aggregation and serum protein profiling. No sign of toxicity and mortality was observed in all the tested parameters of nanocomposite treated animal model. Hemocompatibility studies indicate that nanocomposite treatment was not shown hemolysis, changes in antioxidative enzymes and serum protein profiling which all confirms the best biocompatibility of the synthesised nanocomposite. Phytotoxic effect of the nanocomposite studied with Vigna mungo, Vigna radiata) and Brassica nigra seeds indicate that the nanocomposite treatment was not affecting seedlings emergence or germination index. All these findings unmistakably uncover that the nanocomposite fabricated HBsAg vaccine nanoformulation utilised as a successful immunising agent which constructed from its high immunogenic property and best biocompatibility against appropriate test model framework and investigated another sight in inoculation immunology part.

Exposure to particle debris generated from passenger and truck tires induces different genotoxicity and inflammatory responses in the RAW 264.7 cell line.

A number of studies have shown variable grades of cytotoxicity and genotoxicity in in vitro cell cultures, laboratory animals and humans when directly exposed to particle debris generated from tires. However, no study has compared the effects of particles generated from passenger tires with the effects of particles from truck tires. The aim of this study was to investigate and relate the cyto- and genotoxic effects of different types of particles (PP, passenger tire particles vs. TP, truck tire particles) in vitro using the phagocytic cell line RAW 264.7 (mouse leukaemic monocyte macrophage cell line). The viability of RAW 264.7 cells was determined by the 3- (4,5-dimethylthiazol-2-yl) -5- (3-carboxymethoxyphenyl) -2- (4-sulfophenyl) -2H-tetrazolium (MTS) assay following exposure for 4, 24 and 48 hours to different particle concentrations (10 μg / ml, 25 μg / ml, 50 μg / ml, 100 μg / ml). The effects of particles of passenger and truck tires on cell proliferation and genotoxicity were evaluated by means of the cytokinesis-block micronucleus (CBMN) assay following exposure for 24 hours to different particle concentrations (10 μg / ml, 25 μg / ml, 50 μg / ml, 100 μg / ml). In MTS assay, after 24 hours, it was found that PP induced a 30% decrease in metabolic activity at a concentration of 10 μg/ml, while TP caused reductions of 20% and 10% at concentrations of 10 μg/ml and 50 μg/ml, respectively. At 48 hours after the treatments, we observed increased metabolic activity at 50 μg/ml and 100 μg/ml for the PP while only at 50 μg/ml for the TP. The CBMN assay showed a significant increase in the number of micronuclei in the cells incubated with PP in all experimental conditions, while the cells treated with TP showed a meaningful increase only at 10 μg /ml. We utilized the TNF-α ELISA mouse test to detect the production of tumour necrosis factor-alpha (TNF-α) in RAW 264.7 cells. The effect of passenger and truck particles on TNF-α release was evaluated following exposure for 4 and 24 hours.After 4 hours of incubation, the cells treated with PP and TP at 100 μg / ml showed a slight but significant increase in TNF-α release, while there was a significant increase in the release of TNF-α after 24 hours of incubation with both tire samples in the cells treated with 50 and 100 μg / ml PP. The data obtained show a higher cytotoxic, clastogenic/genotoxic and inflammatory effects of passenger compared to the truck tire particles.

2,6-Dimethoxy-1,4-benzoquinone, isolation and identification of anti-carcinogenic, anti-mutagenic and anti-inflammatory component from the juice of Vitis coignetiae

Previously we demonstrated the anti-tumorigenic, anti-mutagenic and anti-inflammatory effects of the juice of Vitis coignetiae (yamabudo), and identified caftaric acid as an anti-mutagenic component from the juice. In the present study, we investigated the isolation of anti-inflammatory components in yamabudo juice supposing that the anti-inflammatory components in yamabudo are also responsible for the anti-tumorigenic activity. The suppressing effect on nitric oxide production in mouse leukemic monocyte with LPS was used as a separation marker. Three components comprising 2,6-dimethoxy-1,4-benzoquinone (DBQ), fertaric acid and caftaric acid were isolated and identified from the juice of V. coignetiae as anti-inflammatory ingredients. Inhibitory effects were found of DBQ on the mutagenicity of dimethylbenzo[a]anthracene, aflatoxin B1, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in the Ames test. Topical application of DBA significantly inhibited TPA-induced edema of mouse ears. The anti-tumorigenic effect of DBQ on the promotion and initiation stages of mouse skin tumorigenesis was investigated, and topical administration of DBQ on the promotion stage significantly decreased tumor development in mice skin. DBQ is a potential candidate for the chemopreventive effect of V. coignetiae.

Enhanced Tribological, Electrochemical, and Biocompatibility Properties of Ti6Al4V Alloy Through Gas Nitriding and CN Coating Deposition

The tribological properties, electrochemical corrosion resistance, and biocompatibility performance of Ti6Al4V alloy were improved through a duplex surface treatment process consisting of high-temperature gas nitriding followed by amorphous carbon nitride (CN) coating deposition. The tribological properties of the specimens were evaluated using a reciprocating sliding wear tester, while the electrochemical properties were examined by potentiodynamic polarization tests. Finally, the biocompatibility of the samples was investigated by means of cytotoxicity tests performed using mouse leukemic monocyte macrophage cells (Raw 264.7). The duplex treatment significantly improved the tribological performance of the Ti6Al4V sample. In particular, compared to an untreated Ti6Al4V sample, the duplex surface treatment (CN-NTs) reduced the wear depth by around 55 times when sliding against a 316L counterbody and 16 times when sliding against a Ti6Al4V counterbody. Of the various specimens, the CN-T sample showed the best corrosion resistance, while the CN-NT sample showed the best biocompatibility performance.

α-Sulfonamidophosphonates as new anti-mycobacterial chemotypes: Design, development of synthetic methodology, and biological evaluation

Tuberculosis (TB) is the leading cause of death worldwide due to bacterial infection. The scarcity of effective drugs to treat the disease and the compounded problems due to the development of resistance to the available therapeutics and TB-HIV synergism drive medicinal chemists to search for new anti-Mtb chemotypes. Towards this endeavor, the α-sulfonamidophosphonate moiety has been identified as new anti-Mtb chemotype through the scaffold hopping as the design strategy, development of an effective synthetic methodology using green chemistry tools, and evaluation of anti-TB activity of the synthesized compounds against Mtb (Mycobacterium tuberculosis) H37Rv. Out of the sixteen compounds, five have been found to have MIC values of 1.56 μg/mL and one 3.125 μg/mL. The five most active compounds are non-cytotoxic to RAW 264.7 (mouse leukemic monocyte macrophage) cell lines. The compounds are found to possess acceptable values of the various parameters for drug likeness in accordance with the Lipinski rule with the topological surface area (tPSA) of >70 that suggest eligibility of these new molecular entities for further consideration as potential drug candidates.

Tribological performance, electrochemical behavior and biocompatibility of high-temperature gas-nitrided Ti6Al4V alloy

PurposeThis paper aims to investigate the tribology, corrosion resistance and biocompatibility of high-temperature gas-nitrided Ti6Al4V alloy.Design/methodology/approachThe tribological properties were studied by reciprocating wear tester. The corrosion resistance was evaluated by using potentiodynamic polarization test. The purified mouse leukaemic monocyte macrophage cells are used to investigate the biocompatibility.FindingsThe results show that the nitriding treatment leads to a significant improvement in the hardness and tribological properties of Ti6Al4V alloy. Specifically, compared to untreated Ti6Al4V, the hardness increases from 3.24 to 9.02 GPa, while the wear rate reduces by 12.5 times in sliding against a Ti6Al4V cylinder and 19.6 times in sliding against a Si3N4 ball. Furthermore, the nitriding treatment yields an improved corrosion resistance and a biocompatibility similar to that of untreated Ti6Al4V.Originality/valueThe nitrided Ti6Al4V alloy is an ideal material for the fabrication of load-bearing artificial implants.

Tribological, electrochemical and biocompatibility properties of Ti6Al4V alloy produced by selective laser melting method and then processed using gas nitriding, CN or Ti-C:H coating treatments

Ti6Al4V alloy samples prepared by selective laser melting (SLM) were nitrided at a high temperature of 900 °C and then coated with amorphous carbon nitride (CN) or DLC-doped Ti (TiC:H) thin films using a closed field unbalanced magnetron sputtering (CFUMS) system. The microstructures, mechanical properties and coating adhesion strengths of the various specimens were evaluated by X-ray diffraction, nanoindentation tests and Rockwell hardness tests, respectively. The tribological properties of the samples were examined in 0.89 wt% NaCl solution by means of reciprocating sliding wear tests performed against 316L, Si3N4 and Ti6Al4V balls under a load of 10 N for 1440 s. In addition, the corrosion properties were evaluated by potentiodynamic polarization tests. Finally, cytotoxicity tests were performed using mouse leukemic monocyte macrophage cells (Raw 264.7) for culture periods of 1, 3 and 5 days, respectively. Overall, the Ti6Al4V sample processed using a duplex nitriding and DLC coating treatment exhibited a good coating adhesion, the highest wear resistance, the best corrosion resistance and excellent biocompatibility.

Isolation and Structure Elucidation of Cembranoids from a Dongsha Atoll Soft Coral Sarcophyton stellatum.

Six new polyoxygenated cembrane-based diterpenoids, stellatumolides A–C (1–3), stellatumonins A and B (4 and 5), and stellatumonone (6), were isolated together with ten known related compounds (7–16) from the ethyl acetate (EtOAc) extract of soft coral Sarcophyton stellatum. The structures of the new compounds were established by extensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and data comparison with related structures. Compounds 8 and 14 were isolated from a natural source for the first time. The isolated metabolites were shown to be not cytotoxic against a limited panel of cancer cells. Compound 9 showed anti-inflammatory activity by reducing the expression of proinflammatory cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proteins in lipopolysaccharide (LPS)-stimulated mouse leukaemic monocyte macrophage (RAW 264.7) cells.

Novel Reduced Graphene Oxide/Zinc Silicate/Calcium Silicate Electroconductive Biocomposite for Stimulating Osteoporotic Bone Regeneration.

In the absence of external assistance, autogenous healing of bone fracture is difficult due to impaired regeneration ability under osteoporosis pathological conditions. In this study, a reduced graphene oxide/zinc silicate/calcium silicate (RGO/ZS/CS) conductive biocomposite with an optimal surface electroconductivity of 5625 S/m was prepared by a two-step spin-coating method. The presence of lamellar apatite nanocrystals on the surfaces of the biocomposite suggests that it has good in vitro biomineralization ability. The silicon and zinc released from the biocomposite induced a significant increase in the osteogenesis of mouse bone mesenchymal stem cells (mBMSCs). Furthermore, alkaline phosphatase activities were further promoted when 3 μA direct current was applied to stimulate the mBMSCs that were cultured on the RGO/ZS/CS surface. However, electrical stimulation failed to further upregulate the osteogenesis-related gene expression. Moreover, RGO/ZS/CS extracts were found to suppress the receptor activator of nuclear factor-κB ligand-induced osteoclastic differentiation of mouse leukemic monocyte macrophages (RAW264.7 cells). Although the zinc ions in the RGO/ZS/CS extracts showed an inhibitory role in human umbilical vein endothelial cell (HUVEC) proliferation, dilutions of the RGO/ZS/CS extracts (1/16, 1/32, and 1/64) promoted HUVEC proliferation, and their angiogenesis-related gene expression was also upregulated. On the basis of the results of the in vitro angiogenesis model, more interconnected tubes formed when the above dilutions of RGO/ZS/CS extracts were added to ECMatrix. The new RGO/ZS/CS electroconductive biocomposite has potential to be used for stimulating osteoporotic bone regeneration.

Evaluation of nitric oxide inhibition effect in LPS-stimulated RAW 264.7 macrophages by phytochemical constituents from Mesua beccariana, Mesua congestiflora, and Mesua ferrea

This study was conducted to evaluate the anti-inflammatory properties of the secondary metabolites and extracts from Mesua species by using nitric oxide inhibition and protein denaturation assays. Our phytochemical investigations on three species of Mesua plants, Mesua beccariana, M. congestiflora, and M. ferrea have resulted in sixteen pure metabolites. The anti-inflammatory effects of the crude extracts, as well as the pure metabolites were evaluated against mouse leukemic monocyte RAW 264.7 macrophage cell line and protein denaturation assay. All the crude extracts exhibited concentration dependent inhibition of the anti-inflammatory activity against RAW 264.7 cells. The effects of the crude extracts on inhibition of egg albumin denaturation were also evaluated. The crude extracts of M. beccariana and M. congestiflora showed significant inhibition of protein denaturation as compared to the reference drug, diclofenac sodium. Among the pure constituents tested, three xanthones, macluraxanthone (7), α-mangostin (10) and mesuarianone diacetate B (13) possessed significant in-vitro anti-inflammatory properties against RAW 264.7 cells with IC50 values of less than 16.0 μM. The structure-activity relationship study of these xanthone was predicted based on the anti-inflammatory effects. It is deduced that xanthone derivatives which have trihydroxylated prenylated, diprenylated and indirectly prenylated and acetylated substituent groups on the xanthone skeleton contributed remarkable anti-inflammatory activity.

Improved tribological properties, electrochemical resistance and biocompatibility of AISI 316L stainless steel through duplex plasma nitriding and TiN coating treatment.

AISI 316L specimens were nitrided using a low temperature (390℃) plasma nitriding process and then coated with a thin layer of titanium nitride by closed field unbalanced magnetron sputtering. The microstructure, adhesion properties and hardness of the duplex-treated samples were examined using X-ray diffraction, scratch testing and nanoindentation, respectively. In addition, the tribological properties were investigated by means of reciprocating wear tests performed against 316L, Si3N4 and Ti6Al4V balls under a load of 10 N for 24 min in 0.9% NaCl solution. The electrochemical resistance of the samples was evaluated by potentiodynamic polarisation tests. Finally, the biocompatibility of the samples was investigated by seeding purified mouse leukemic monocyte macrophage cells (Raw 264.7) on the sample surface for one, three and five days, respectively. In general, the results showed that the duplex nitriding and titanium nitride coating process significantly improved the tribological properties, electrochemical resistance and biocompatibility of the AISI 316L samples.

HS-AFM and SERS Analysis of Murine Norovirus Infection: Involvement of the Lipid Rafts

Studies on human norovirus are severely hampered by the absence of a cell culture system until the discovery of murine norovirus (MNV). The cell membrane domains called lipid rafts have been defined as a port of entry for viruses. This study is conducted to investigate murine norovirus binding on the mouse leukemic monocyte macrophage cell line. Lipid raft related structures are extracted from cells by detergent treatment resulting detergent-resistant membrane (DRMs) domains. The real-time polymerase chain reaction technique is performed to detect the viral genome, thereby the MNV binding on the DRMs. The interactions between MNV and DRMs are investigated by high-speed atomic force microscopy (HS-AFM) combined with surface-enhanced Raman spectroscopy (SERS). The inoculation of the virus onto cells results in the aggregations of detergent-resistant membrane domains significantly. The characteristic Raman band of MNV is found in inoculated samples. To be sure that these results are originated from specific interactions between DRM and MNV, methyl-β-cyclo-dextrin (MβCD) is applied to disrupt lipid rafts. The MNV binding on DRMs is precluded by the MβCD treatment. The cholesterols chains are defined as a key factor in the interactions between norovirus and DRMs. The authors conclude that the MNV binding involves the presence of DRMs and cholesterol dependent.

Effects of Ti-C:H coating and plasma nitriding treatment on tribological, electrochemical, and biocompatibility properties of AISI 316L.

Ti-C:H coatings were deposited on original, nitrided, and polished-nitrided AISI 316L stainless steel substrates using a closed field unbalanced magnetron sputtering system. Sliding friction wear tests were performed in 0.89 wt.% NaCl solution under a load of 30 N against AISI 316L stainless steel, Si3N4, and Ti6Al4V balls, respectively. The electrochemical properties of the various specimens were investigated by means of corrosion tests performed in 0.89 wt.% NaCl solution at room temperature. Finally, the biocompatibility properties of the specimens were investigated by performing cell culturing experiments using purified mouse leukemic monocyte macrophage cells (Raw264.7). In general, the results showed that plasma nitriding followed by Ti-C:H coating deposition provides an effective means of improving the wear resistance, anti-corrosion properties, and biocompatibility performance of AISI 316L stainless steel.

Anti-inflammatory and cytotoxic effects of methanol, ethanol, and water extracts of Angelicae Dahuricae Radix.

Angelicae Dahuricae Radix has been used for the treatment of headaches, rhinitis, and colds in traditional medicine. Methanol, ethanol, and water extracts of Angelicae Dahuricae Radix were collected. A statistically significant reduction in the cellular viability of the mouse leukemic monocyte macrophage cell line was noted after treatment with water extracts of Angelicae Dahuricae Radix. Stimulation with lipopolysaccharides (LPS) for 24 h led to a robust increase in nitric oxide production, but Angelicae Dahuricae Radix at 400 μg/mL concentration significantly suppressed nitric oxide produced by the LPS-stimulated RAW 264.7 cells in 70% ethanol, absolute ethanol, 70% methanol, absolute methanol, and boiling water groups (P < 0.05). Pretreatment with absolute ethanol extract of Angelicae Dahuricae Radix suppressed the LPS-stimulated inducible nitric oxide synthase, interleukin-1β, and cycloxygenase-2 expression. Angelicae Dahuricae Radix showed significant cytotoxic effects on the human adenocarcinoma cell line and keratin-forming cell line. (J Oral Sci 58, 125-131, 2016).

Improved tribological, electrochemical and biocompatibility properties of Ti6Al4V alloy by gas-nitriding and Ti–C:H coating

Ti–C:H coatings are deposited on untreated Ti6Al4V alloy samples and high-temperature gas-nitrided Ti6Al4V alloy samples by means of CFUBMS. Therefore, four types of specimen, i.e., Ti6Al4V, nitrided Ti6Al4V (N-Ti6Al4V), T–C:H-coated Ti6Al4V (Ti–C:H/Ti6Al4V) and T–C:H-coated nitrided Ti6Al4V (Ti–C:H/N-Ti6Al4V) are considered. The microstructure, adhesion and hardness of the Ti–C:H coatings are examined using a Raman spectrometer, scratch tester and nanoindenter, respectively. The tribological properties of the coated and uncoated samples are investigated using a reciprocating sliding wear tester in NaCl solution. The corrosion performance of the four specimens is evaluated by means of potentiodynamic polarization tests. Finally, the biocompatibility of the various samples is investigated using purified mouse leukaemic monocyte macrophage cells (Raw 264.7). Overall, the results show that the gas-nitriding treatment increases both the hardness and the surface roughness of the samples. Moreover, of the various samples, the Ti–C:H/Ti6Al4V sample exhibits excellent tribological properties and the best corrosion resistance and biocompatibility performance.

The role of Rab6 GTPase in the maturation of phagosome against Staphylococcus aureus

Phagocytosis, an evolutionarily conserved process in animals, plays a central role in host defense against pathogens. As reported, Rab6 GTPase was involved in the regulation of hemocytic phagocytosis in invertebrates. However, the role of Rab6 GTPase in mammalian phagocytosis remains to be addressed. In this study, the results showed that Rab6 GTPase took great effects on phagocytosis of mouse leukemic monocyte macrophages (RAW 264.7 cells). It was revealed that Rab6 GTPase was required during the phagosome maturation by its interaction with bicaudal-D1 (BICD1) protein. Further data presented that the Rab6 GTPase-regulated phagocytosis could influence the proliferation of Staphylococcus aureus in macrophages. Therefore, our study demonstrated a novel insight into the mechanism of regulation of mammalian phagocytosis by Rab6 GTPase and a novel strategy for the control of Staphylococcus aureus.

Uptake of cerium oxide nanoparticles and its influence on functions of mouse leukemic monocyte macrophages

Exposure of the CeO2 nanoparticles (NPs) causes a public concern on their potential health risk due to their wide applications in the fields of fuel additive, commodities, pharmaceutical, and other industries. In this study, the interactions between two commercial CeO2 NPs (D-CeO2 from Degussa and PC-CeO2 from PlasmaChem) and mouse leukemic monocyte macrophage Raw264.7 cells were investigated to provide a fast and in-depth understanding of the biological influences of the NPs. Both types of the CeO2 NPs had a negative surface charge around −12 mV and showed a tendency to form aggregates with sizes of 191 ± 5.9 and 60.9 ± 2.8 nm in cell culture environment, respectively. The cellular uptake of the CeO2 NPs increased along with the increase of feeding dosage and prolongation of the culture time. The PC-CeO2 NPs had a faster uptake rate and reached higher cellular loading amount at the highest feeding concentration (200 µg/mL). In general, both types of the CeO2 NPs had rather small cytotoxicity even with a dosage as high as 200 µg/mL. The D-CeO2 NPs showed a relative stronger cytotoxicity especially at higher concentrations and longer incubation time. The NPs were dispersed in vacuoles (most likely endosomes and lysosomes) and cytoplasm. Although both types of the CeO2 NPs could suppress the production of reactive oxygen species, they impaired the mitochondria membrane potential to some extent. The cytoskeleton organization was altered and consequently the cell adhesion ability decreased after uptake of both types of the CeO2 NPs.