Ubiquitin-like protein MNSFß regulates glycolysis and promotes cell proliferation with HSC70 assistance.

Monoclonal non-specific suppressor factor ß (MNSFß) is a universally expressed ubiquitin-like protein that has multiple biological functions. MNSFß modifies its target molecules through covalent conjugation. Most recently, we identified a molecular chaperone, HSC70, that facilitates the stabilization of aggregable MNSFß. In the current study, we determined the role of HSC70 in stabilizing unstable MNSFß. HSC70 promoted the correct folding of MNSFß both in vitro and in vivo. We also examined the regulatory function of MNSFß in cell proliferation and glycolysis. MNSFß siRNA and HSC70 siRNA treatment attenuated lactate release from Raw264.7 macrophage-like cells. MNSFß siRNA inhibited glucose uptake in Raw264.7 cells. We found that glucose transporter 1 (GLUT1) is an important membrane protein involved in the regulatory function of MNSFß during glycolysis. MNSFß siRNA inhibited the increased GLUT1 expression in LPS-stimulated cells, suggesting that MNSFß controls the inflammatory response through GLUT1 regulation. We identified several important molecules, including lactate dehydrogenase A, which are regulated by MNSFß and involved in glucose metabolism. Here we firstly report that MNSFß regulates glycolysis and promotes cell proliferation.

Quercetin and HSC70 coregulate the anti-inflammatory action of the ubiquitin-like protein MNSFß.

BACKGROUND: Quercetin is a flavonol that modifies many cellular processes. Monoclonal nonspecific suppressor factor ß is a member of the ubiquitin-like family of proteins that are involved in various biological processes. It has been demonstrated that quercetin regulates the effect of MNSFß on tumor necrosis factor-α secretion in lipopolysaccharide (LPS)-stimulated macrophages. This study found that quercetin and the heat shock protein HSC70 coregulate the action of MNSFß. METHODS AND RESULTS: Quercetin dose-dependently suppressed the LPS/interferon γ-induced nitric oxide production without cytotoxicity in the macrophage-like cell line Raw264.7. SiRNA knockdown experiments showed that quercetin inhibited the MNSFß and HSC70 siRNA-mediated enhancement of TNFα and the production of RANTES, a member of C-C chemokine superfamily, in LPS-stimulated Raw264.7 cells. Western blot analysis showed that quercetin and HSC70 regulated ERK1/2 activation and LPS-stimulated IκBα degradation by affecting the complex formation of MNSFß and the proapoptotic protein Bcl-G. Moreover, MNSFß is implicated in TLR4/MyD88 signaling but not in TLR3 signaling. CONCLUSIONS: HSC70 is an important chaperone that facilitates the stabilization of MNSFß. Quercetin may negatively control the function of MNSFß by regulating the action of the molecular chaperone HSC70. MNSFß mediates TLR4/Myd88 signaling but not TLR3 signaling.

Heat shock protein 60 negatively regulates the biological functions of ubiquitin-like protein MNSFß in macrophages.

Monoclonal nonspecific suppressor factor ß (MNSFß) is a ubiquitously expressed ubiquitin-like protein known to be involved in various biological functions. Previous studies have demonstrated that MNSFß covalently modify its target proteins including Bcl-G, a proapoptotic protein. In this study, we purified a 65 kDa MNSFß adduct from mouse liver lysates by sequential chromatography on DEAE and glutathione S-transferase (GST)-fusioned MNSFß immobilized on glutathione-Sepharose beads in the presence of ATP. MALDI-TOF mass spectrometry fingerprinting revealed that this MNSFß adduct consists of an 8.5 kDa MNSFß and heat shock protein 60 (HSP60), a mitochondrial protein involved in protein folding. Fingerprinting analysis of the MNSFß adduct demonstrates that MNSFß conjugates to HSP60 with a linkage between the C-terminal Gly74 and Lys481. HSP60 siRNA neutralized the inhibition of apoptosis by MNSFß siRNA in LPS/IFNγ-stimulated Raw264.7, a murine macrophage cell line. HSP60 siRNA also down-regulated the enhancement of TNFα production by MNSFß siRNA in LPS-stimulated Raw264.7 cells. Here, we firstly report that MNSFß activity is negatively regulated by molecular chaperone.

Subchronic intravenous toxicity study of biofunctional ZnO and its application as a fluorescence probe for cell-specific targeting.

Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early cancer is a great challenge. Herein, we choose the visible-light emitting zinc oxide non-core/shell type nanoparticle (NP) fluorophores (ZHIE) as prototypical materials. We have reported on these materials previously. The results showed that the ZHIE NPs exhibited good water solubility and good biocompatibility. This study was conducted to investigate the toxicity of ZHIE NPs when intravenously administered to mice repeatedly at the dose required for successful tumor imaging in vivo. Anti-macrophage-1 antigen (Mac1), a macrophage differentiation antigen, antibody-conjugated ZHIE NPs successfully realized targeted imaging of murine macrophage cell line Raw264.7 cells. In conclusion, ZHIE NPs are not toxic in vivo and antibody-conjugated ZHIE NPs have great potential in applications, such as single cell labeling.

Ubiquitin-like protein MNSFß noncovalently binds to molecular chaperone HSPA8 and regulates osteoclastogenesis.

MNSFß, a ubiquitin-like protein, covalently binds to various target proteins including proapoptotic Bcl-G. During the course of isolation of MNSFß-conjugating enzyme(s), we identified a novel target protein for MNSFß. MALDI-TOF MS fingerprinting revealed that the MNSFß-interacting protein is HSPA8 (heat shock 70-kDa protein 8). We observed that MNSFß noncovalently binds to HSPA8 in the presence of ATP in vitro. Double knockdown of MNSFß and HSPA8 strongly inhibited RANKL-induced osteoclastogenesis from Raw264.7 macrophage-like cells. The same treatment inhibited RANKL-induced ERK1/2 and p38 phosphorylation and TNFα production, suggesting that the association of MNSFß with HSPA8 may promote RANKL-induced osteoclastogenesis. This is the first report that MNSFß binds to a protein substrate via the noncovalent association and exerts biological effects.

Ubiquitin-like protein MNSFß covalently binds to cytosolic 10-formyltetrahydrofolate dehydrogenase and regulates thymocyte function.

MNSFß is a ubiquitously expressed member of the ubiquitin-like family that has been involved in various biological functions. Previous studies have demonstrated that MNSFß covalently binds to various target proteins including Bcl-G, a proapoptotic protein. In this study, we purified a 115 kDa MNSFß adduct from murine liver lysates by sequential chromatography on DEAE and anti-MNSFß IgG-conjugated Sepharose in the presence of ATP. MALDI-TOF MS fingerprinting revealed that this MNSFß adduct consists of an 8.5 kDa MNSFß and 10-formyltetrahydrofolate dehydrogenase (FDH), an abundant enzyme of folate metabolism. Interestingly, MNSFß preferably binds to cytosolic but not mitochondrial FDH. Fingerprinting analysis of the MNSFß adduct demonstrate that MNSFß conjugates to cytosolic FDH with a linkage between the C-terminal Gly74 and Lys72. The 115 kDa MNSFß/FDH complex was not expressed in any of the tissues examined, indicating that this adduct formation is not ubiquitous. We found that MNSFß/FDH complex formation was induced by dexamethasone in thymocytes. Double knockdown of MNSFß and FDH strongly reduced dexamethasone-induced apoptosis. Collectively, MNSFß/FDH complex formation may positively regulate apoptosis in thymocytes.

Ubiquitin-like protein MNSFß negatively regulates T cell function and survival.

Monoclonal non-specific suppressor factor ß (MNSFß) is a ubiquitously expressed member of the ubiquitin-like family that is involved in various biological functions. Previous studies have demonstrated that MNSFß covalently binds to intracellular pro-apoptotic protein Bcl-G and regulates apoptosis in macrophages. In this study, we demonstrate that MNSFß negatively regulates T cell function. In murine T-helper type 2 clone, D10.G4.1 (D10) cells transfected with MNSFß cDNA, CD3/CD28-induced ERK1/2 phosphorylation leading to IL-4 production was significantly inhibited. The formation of MNSFß-Bcl-G complex was induced by the CD3/CD28 stimulation. Co-transfection with MNSFß and Bcl-G greatly enhanced CD3/CD28-induced apoptosis in D10 cells. Similarly, co-over-expression of MNSFß and Bcl-G caused a marked enhancement of apoptosis in purified splenic T cells. Interestingly, this MNSFß adduct was also induced in T cells derived from DO11.10 mice stimulated with antigen. Collectively, CD3/CD28-inducible MNSFß-Bcl-G complex may be involved in the regulation of T cell function and survival.

Ubiquitin-like protein MNSFß covalently binds to Bcl-G and enhances lipopolysaccharide/interferon γ-induced apoptosis in macrophages.

Monoclonal non-specific suppressor factor ß (MNSFß) is a ubiquitously expressed member of the ubiquitin-like family that is involved in various biological functions. Previous studies have demonstrated that MNSFß covalently binds to intracellular pro-apoptotic protein Bcl-G and regulates the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) cascade in the mouse macrophage cell line Raw264.7. In this study, we demonstrate that MNSFß promotes lipopolysaccharide (LPS)/interferon γ (IFNγ)-induced apoptosis of Raw264.7 macrophages. In Raw264.7 cells treated with MNSFß small interfering RNA (siRNA), LPS/IFNγ- or NO donor S-nitrosoglutathione-induced apoptosis was inhibited. siRNA-mediated knockdown of MNSFß did not affect inducible nitric-oxide synthase (iNOS) expression in LPS/IFNγ-stimulated Raw264.7 cells. Conversely, co-transfection with MNSFß and Bcl-G greatly enhanced LPS/IFNγ- induced apoptosis in Raw264.7 cells, accompanied by increased expression of p53 and decreased Cox-2 activity. Unlike co-transfection with wild-type MNSFß, co-transfection of a mutant MNSFß (G74A) and Bcl-G did not result in enhancement of LPS/IFNγ-induced apoptosis. Co-over-expression of MNSFß and Bcl-G reduced S-nitrosoglutathione-induced ERK1/2 phosphorylation. Furthermore, electrophoretic mobility shift assay experiments revealed that MNSFß down-regulates the ERK/activator protein 1 (AP-1) signaling cascade which leads to Cox-2 activation. We also observed that MNSFß-Bcl-G promotes LPS/IFNγ-induced apoptosis of mouse peritoneal macrophages, together with a decrease in Cox-2 expression. Taken together, our data indicate an apoptosis-enhancing effect of MNSFß-Bcl-G is due in part to down-regulation of Cox-2 activation in macrophages.

Fretting fatigue behaviour of Ni-free high-nitrogen stainless steel in a simulated body fluid.

Fretting fatigue behaviour of Ni-free high-nitrogen steel (HNS) with a yield strength of about 800 MPa, which was prepared by nitrogen gas pressurized electroslag remelting, was studied in air and in phosphate-buffered saline (PBS(-)). For comparison, fretting fatigue behaviour of cold-rolled SUS316L steel (SUS316L(CR)) with similar yield strength was examined. The plain fatigue limit of HNS was slightly lower than that of SUS316L(CR) although the former had a higher tensile strength than the latter. The fretting fatigue limit of HNS was higher than that of SUS316L(CR) both in air and in PBS(-). A decrease in fatigue limit of HNS by fretting was significantly smaller than that of SUS316L(CR) in both environments, indicating that HNS has better fretting fatigue resistance than SUS316L(CR). The decrease in fatigue limit by fretting is discussed taking into account the effect of friction stress due to fretting and the additional influences of wear, tribocorrosion and plastic deformation in the fretted area.

Chronic administration of cardanol (ginkgol) extracted from ginkgo biloba leaves and cashew nutshell liquid improves working memory-related learning in rats.

Cardanol (ginkgol) extracted from Ginkgo biloba leaves and cashew nutshell liquid enhances the growth of NSC-34 immortalized motor neuron-like cells and, when chronically administered to young rats, improves working memory-related learning ability as assessed by eight-arm radial maze tasks. These findings suggest that cardanol is one of the components in Ginkgo biloba leaves that improves cognitive learning ability.

Ubiquitin-like protein MNSFß regulates TLR-2-mediated signal transduction.

Post-translational modification by monoclonal nonspecific suppressor factor ß (MNSFß) has been involved in the regulation of a variety of cellular processes. Previous studies have demonstrated that MNSFß covalently binds to the intracellular pro-apoptotic protein Bcl-G and regulates TLR-4-mediated signal transduction. Recently, we found that MNSFß also covalently conjugates to endophilin II, a member of the endophilin A family, and inhibits the signal pathway upstream of IKK activation, but not downstream of TLR-2 signaling. In this study, we further examined the mechanism of action of MNSFß in TLR-2-mediated signal transduction in macrophage-like cell line Raw264.7 cells. Although MNSFß siRNA enhanced Pam(3)CDK(4) (TLR-2-specific ligand)-stimulated TNFα production, Bcl-G siRNA did not affect. MNSFß cDNA inhibited the Pam(3)CDK(4)-stimulated TNFα production. High-molecular weight (130 kDa) MNSFß-adduct was induced in Pam(3)CDK(4)-stimulated Raw264.7 cells. This MNSFß-adduct was not induced by LPS, indicative of the specificity of TLR-2-mediated signal transduction. Similar observations were seen in BALB/c peritoneal macrophages. Interestingly, 40-kDa MNSFß-adduct was tyrosine phosphorylated by Pam(3)CDK(4) stimulation. Collectively, novel MNSFß-adducts may regulate TLR-2 signaling pathway in macrophages.

Anti-allergic effect of the flavonoid myricitrin from Myrica rubra leaf extracts in vitro and in vivo.

Flavonoids are ingested by the general population as anti-oxidant and anti-inflammatory agents. In this study, we investigated the effects of myricitrin, a flavonoid rich in Myrica rubra leaf, upon anti-inflammatory action. Myrica rubra leaf extracts inhibited pro-inflammatory TNFα production in a macrophage cell line, Raw264.7 cells. We observed that the serum IgE levels in the leaf extract-treated DO11.10, a mouse allergy model, were down-regulated. HPLC was performed to demonstrate that M. rubra leaf extracts contain a large amount of myricitrin. We observed an inhibitory effect of HPLC-purified myricitrin on TNFα production in Raw264.7 cells. Thus, myricitrin may be of potential interest in the management of inflammatory conditions.

Ubiquitin-like protein MNSFß/endophilin II complex regulates Dectin-1-mediated phagocytosis and inflammatory responses in macrophages.

Post-translational modification by monoclonal nonspecific suppressor factor ß (MNSFß) has been implicated in the regulation of a variety of cellular events. Previous studies have demonstrated that MNSFß covalently binds to the intracellular pro-apoptotic protein Bcl-G in a macrophage cell line, Raw264.7, suggesting involvement of this ubiquitin-like protein in apoptosis. Most recently, we found that MNSFß covalently conjugates to endophilin II, a member of the endophilin A family, and inhibits phagocytosis by macrophages. In this study, we further examined the mechanism of action of MNSFß/endophilin II complex in the phagocytosis of zymosan. MNSFß/endophilin II I mediated inhibition of phagocytosis in Raw264.7 cells was neutralized by anti-Decti-1, ß-glucan receptor, mAb, indicating that MNSFß/endophilin II is a mediator of Dectin-1 signaling in regulating phagocytosis. The ß-glucan-dependent TNFα response to zymosan was significantly increased by the treatment with endophilin II siRNA and/or MNSFß siRNA. Conversely, cotransfection of endophilin II and MNSFß cDNAs inhibited the enhancement of zymosan-induced TNFα production. Interestingly, endophilin II siRNA did not affect Pam3CSK4 (TLR2 specific ligand)-induced TNFα production. Endophilin II and/or MNSFß siRNA enhanced zymosan-induced IκBα degradation. Together, these results demonstrate that MNSFß/endophilin II inhibits the signal pathway upstream of IKK activation, but not downstream of TLR2 signaling.

The ubiquitin-like protein monoclonal nonspecific suppressor factor beta conjugates to endophilin II and regulates phagocytosis.

Monoclonal nonspecific suppressor factor beta (MNSFbeta) is a ubiquitously expressed member of the ubiquitin-like family that has been implicated in various biological functions. Previous studies have demonstrated that MNSFbeta covalently binds to the intracellular proapoptotic protein Bcl-G in cells of the macrophage cell line Raw264.7, suggesting involvement of this ubiquitin-like protein in apoptosis. In this study, we purified a 62 kDa MNSFbeta adduct from murine liver lysates by sequential chromatography on DEAE and anti-MNSFbeta IgG-conjugated Sepharose. MALDI-TOF MS fingerprinting revealed that this MNSFbeta adduct consists of an 8.5 kDa MNSFbeta and endophilin II, a member of the endophilin A family. MNSFbeta may conjugate to endophilin II with a linkage between the C-terminal Gly74 and Lys294. We confirmed this result by immunoprecipitation/western blot studies. Endophilin II was ubiquitously expressed in various tissues, although a truncated form was observed in liver. The 62 kDa MNSFbeta-endophilin II was specifically expressed in liver and macrophages. Small interfering RNA-mediated knockdown of endophilin II and/or MNSFbeta promoted phagocytosis of zymosan in Raw264.7 cells. Conversely, cotransfection of endophilin II and MNSFbeta cDNAs inhibited the phagocytosis of zymosan. Such inhibition was not observed in cells expressing a mutant of endophilin II in which Lys294 was replaced by arginine. These results suggest that the post-translational modification of endophilin II by MNSFbeta might be implicated in phagocytosis by macrophages.

Quercetin regulates the inhibitory effect of monoclonal non-specific suppressor factor beta on tumor necrosis factor-alpha production in LPS-stimulated macrophages.

Monoclonal non-specific suppressor factor beta (MNSFbeta) is a member of the ubiquitin-like family that has been implicated in various biological functions. Previous studies have demonstrated that MNSFbeta regulates the ERK1/2-MAPK cascade in the macrophage cell line Raw 264.7. In this study, we found evidence that the flavonol quercetin regulates the effect of MNSFbeta on TNFalpha production in LPS-stimulated Raw264.7 cells. Quercetin inhibited MNSFbeta siRNA-mediated enhancement of both TNFalpha production and ERK1/2 phosphorylation in LPS-stimulated Raw264.7 cells. Quercetin decreased the expression of 33.5-kDa MNSFbeta adduct, which is important to the regulation of ERK1/2 activity, in unstimulated Raw264.7 cells. The various flavonoids tested, including other flavonols, did not affect the formation of this adduct. Collectively, MNSFbeta and quercetin might share a common pathway in regulating the ERK1/2 pathway in macrophages. This is the first report describing the involvement of flavonoids in the action of ubiquitin-like proteins.

The ubiquitin-like protein MNSFbeta regulates ERK-MAPK cascade.

MNSFbeta is a ubiquitously expressed member of the ubiquitin-like family that has been implicated in various biological functions. Previous studies have demonstrated that MNSFbeta covalently binds to intracellular proapoptotic protein Bcl-G in mitogen-activated murine T cells. In this study, we further investigated the intracellular mechanism of action of MNSFbeta in macrophage cell line, Raw 264.7 cells. We present evidence that MNSFbeta.Bcl-G complex associates with ERKs in non-stimulated Raw 264.7. We found that MNSFbeta.Bcl-G directly bound to ERKs and inhibited ERK activation by MEK1. In Raw 264.7 cells treated with MNSFbeta small interfering RNA (siRNA) lipopolysaccharide (LPS)-induced ERK1/2 activation was enhanced and LPS-induced JNK and p38 activation was unaffected. SiRNA-mediated knockdown of MNSFbeta increased tumor necrosis factor alpha (TNFalpha) expression at mRNA and protein levels in LPS-stimulated Raw 264.7 cells. Finally, we found that transfection with MNSFbeta expression construct resulted in a significant inhibition of LPS-induced ERK activation and TNFalpha production. Co-transfection experiments with MNSFbeta and Bcl-G greatly enhanced this inhibition. Collectively, these findings indicate that MNSFbeta might be implicated in the macrophage response to LPS.

Noncovalent interaction of MNSFbeta, a ubiquitin-like protein, with histone 2A.

Monoclonal nonspecific suppressor factor (MNSF), a lymphokine produced by murine T cell hybridoma, possesses pleiotrophic antigen-nonspecific suppressive functions. A cDNA clone encoding MNSFbeta, an isoform of the MNSF, has been isolated and characterized. MNSFbeta cDNA encodes a fusion protein consisting of a ubiquitin-like segment (Ubi-L) and ribosomal protein S30. Most recently, we observed that Ubi-L covalently conjugates to Bcl-G, a novel pro-apoptotic protein. In this study, we observed that Ubi-L noncovalently and specifically binds to histone 2A. The maximum binding was observed at a molar ratio equal to 1 for GST-Ubi-L and 2 for histone 2A. Ubi-L formed complex with histone 2A in the presence of 1% Triton X-100. Free Ubi-L was detected in nuclei from unstimulated murine helper T cell line, D10. The increased amounts of free Ubi-L and some Ubi-L adducts were observed in nuclei from mitogen-activated D10 cells. Interestingly, two Ubi-L adducts were unique to the chromatin fraction of nuclei from the activated D10 cells.

Ubiquitin-like polypeptide inhibits cAMP-induced p38 MAPK activation in Th2 cells.

Ubi-L, an isoform of the monoclonal nonspecific suppressor factor (MNSF), is an 8.5-kDa ubiquitin-like polypeptide. Ubi-L exhibits an antigen-nonspecific immunosuppressive function on various target cells including murine T helper type 2 (Th2) clone, D10 cells. Ubi-L specifically binds to cell surface receptors on D10 cells. In this study, we observed that Ubi-L inhibited cAMP-induced IL-5 mRNA expression in D10 cells but not in thymoma cell line EL4. In addition, Ubi-L effectively inhibited cAMP-induced p38 MAPK activation in D10 cells. Ubi-L also showed inhibitory activity on IL-5 and IL-13 production by D10 cells stimulated with phorbol ester plus dibutyryl cAMP. Furthermore, Ubi-L inhibited IL-4 production in Th2 cells derived from primary CD4+ T cells.

Grazing exit electron probe microanalysis of submicrometer inclusions in metallic materials.

Grazing exit electron probe microanalysis (GE-EPMA) is a new method of EPMA in which characteristic X-rays emitted from only near-surface regions of a specimen are detected at extremely low exit angles near 0 degrees (the grazing exit condition). This technique requires the analytical objects exist on a flat surface. Therefore, the GE-EPMA analysis has been used only for the analysis of particles or a thin film on a flat substrate so that there were only few applications for practical analysis. As a new application, we have carried out GE-EPMA analysis of approximately 0.2-microm inclusions on stainless steel, which appeared to be a projection on the specimen surface with chemical etching. The GE-EPMA quantitative results were in excellent agreement with those of inclusions that were extracted from the stainless steel and analyzed by EPMA with conventional exit condition (30 degrees). This method could be, therefore, applied to the analysis of the submicrometer inclusion in a wide variety of metallic materials if the inclusion appears to be a projection with chemical etching treatment.

Characterization of ubiquitin-like polypeptide acceptor protein, a novel pro-apoptotic member of the Bcl2 family.

Monoclonal nonspecific suppressor factor (MNSF) is a cytokine with antigen nonspecific suppressive activity. MNSFbeta (a subunit of MNSF) is a 14.5 kDa fusion protein consisting of a protein with 36% identity with ubiquitin and ribosomal protein S30. The ubiquitin-like segment (Ubi-L) may be cleaved from MNSFbeta in the cytosol. Recently, we have observed that Ubi-L covalently binds to intracellular proteins in mitogen-activated murine T-helper type 2 clone, D.10 cells. In this study, we purified a 33.5 kDa Ubi-L adduct from D.10 cell lysates by sequential chromatography on DEAE, anti-(Ubi-L) Ig-conjugated Sepharose, and hydroxylapatite. MALDI-TOF-MS fingerprinting revealed that this Ubi-L adduct consists of an 8.5 kDa Ubi-L and a Bcl2-like protein, murine orthologue of a previously cloned human BCL-G gene product with pro-apoptotic function. Murine Bcl-G mRNA was highly expressed in testis and significantly in spleen. In addition, the level of Bcl-G mRNA expression was increased in concanavalin A- and interferon gamma-activated D.10 cells. The 33.5 kDa Ubi-L adduct was expressed in spleen but not in testis, even though Bcl-G protein was highly expressed in this tissue. The antisense oligonucleotide to Bcl-G significantly decreased the level of the Ubi-L adduct formation in concanavalin A-activated D.10 cells and the proliferative response of the D.10 cells. These results suggest that the post-translational modification of Bcl-G by Ubi-L might be implicated in T-cell activation.