Agglomerate-free BaTiO3 particles by salt-assisted spray pyrolysis

Optimum conditions for the synthesis of nonagglomerated BaTiO3 particles by salt-assisted spray pyrolysis (SASP) were investigated. The effect of particle residence time in the reactor and salt concentration on the crystallinity and surface morphology of BaTiO3 was examined by x-ray diffraction and scanning electron microscopy. Mixtures of a metal chloride or nitrate salt, dissolved in aqueous precursor solutions, were sprayed by an ultrasonic atomizer into a five-zone hot-wall reactor. By increasing the salt concentration or the particle residence time in the hot zone, the primary particle size was increased, and its surface texture was improved compared to BaTiO3 particles prepared by conventional spray pyrolysis. The SASP-prepared BaTiO3 crystal was transformed from cubic to tetragonal by simply increasing the salt concentration at constant temperature and residence time. Further thermal treatments such as calcination or annealing are not necessary to obtain nonagglomerated tetragonal BaTiO3 (200-500 nm) particles with a narrow size distribution. Increasing the carrier gas flow rate and decreasing the residence time in the hot zone resulted in cubic BaTiO3 particles about 20 nm in diamete

Cytoplasmic tail–dependent internalization of membrane-type 1 matrix metalloproteinase is important for its invasion-promoting activity

Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that degrades the pericellular extracellular matrix (ECM) and is expressed in many migratory cells, including invasive cancer cells. MT1-MMP has been shown to localize at the migration edge and to promote cell migration; however, it is not clear how the enzyme is regulated during the migration process. Here, we report that MT1-MMP is internalized from the surface and that this event depends on the sequence of its cytoplasmic tail. Di-leucine (Leu571–572 and Leu578–579) and tyrosine573 residues are important for the internalization, and the μ2 subunit of adaptor protein 2, a component of clathrin-coated pits for membrane protein internalization, was found to bind to the LLY573 sequence. MT1-MMP was internalized predominantly at the adherent edge and was found to colocalize with clathrin-coated vesicles. The mutations that disturb internalization caused accumulation of the enzyme at the adherent edge, though the net proteolytic activity was not affected much. Interestingly, whereas expression of MT1-MMP enhances cell migration and invasion, the internalization-defective mutants failed to promote either activity. These data indicate that dynamic turnover of MT1-MMP at the migration edge by internalization is important for proper enzyme function during cell migration and invasion

Recent Research Progress in the Applied Microbiology Laboratory : Enzymes, Toxins and Cell-Envelope Structure of Environmental and Pathogenic Bacteria(Recent Topics of the Agricultunal Biological Science in Tohoku University)

Here we describe the current status of our studies of xylanases of Paenibacillus sp. W-61, poly (D-lactic acid) hydrolases of Amycolatopsis sp. K104-1 and Brevibacterium sp. 93, pectin lyase of plant pathogenic Pectobacterium carotovora and bi-component toxins of Staphylococcus aureus. Paenibacillus sp. W-61 utilizes xylan as a carbon source via three enzymes, of which Xyn5 plays a crucial role both in xylan utilization and in the synthesis of the other two xylanases. Understanding the roles of each xylanase in xylan degradation will help to develop an enzymatic preparation of xylose from xylan. The poly (D-lactic acid) [PLA] hydrolases of Amycolatopsis sp. K104-1 and Brevibacterium sp. 93 appear to be novel enzymes with potential for PLA recycling. We recently purified and characterized the PLA hydrolases produced by these bacteria. The plant-soft rotting bacterium P. carotovora produces pectin lyase, a potential pathogenic factor, and a bacteriocin when exposed to DNA-damaging agents. We recently determined the cis-acting regulatory sequences responsible for the DNA-damage-inducible synthesis of the enzyme and bacteriocin. Leukocidin and γ-hemolysin are bi-component toxins that lyse leukocytes and erythrocytes respectively. We describe the molecular structure and pore-forming mechanism of the toxin components encoded by the chromosome and by a phage genome. Finally, we briefly describe the cell-envelope structure of the rumen bacterium Selenomonas ruminantium and its outer membrane protein Mep45 that possibly bridges the outer membrane and the peptidoglycan. The objects of our studies include environmental bacteria (xylanolytic Paenibacillus sp. W-61 and poly (D-lactic acid)-hydrolyzing bacteria Amycolatopsis sp. K104-1 and Brevibacterium sp. 93), as well as the plant and animal pathogens, Pectobacterium carotovora and Staphylococcus aureus, respectively. Here we briefly describe the current status of our investigations into these bacteria, their extracellular enzymes (or toxins), and an outer membrane protein in the rumen bacterium Selenomonas ruminantium subsp. lactilytica. Our research also includes polyglutamate biosynthesis and the degradation enzymes of a Bacillus subtilis Natto starter, acetan (a polysaccharide produced by Acetobacter and Gluconobacter)-degrading enzymes of Paenibacillus sp. and catabolic enzymes of amino acid and polyamine in Pseudomonas aeruginosa PAOl. The topics of these projects are available on our Web site

Membrane-Type 1 Matrix Metalloproteinase Cleaves Cd44 and Promotes Cell Migration

Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP–processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP–dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion

Inhibition of shedding of low-density lipoprotein receptor-related protein 1 reverses cartilage matrix degradation in osteoarthritis

OBJECTIVE: The aggrecanase ADAMTS-5 and the collagenase matrix metalloproteinase 13 (MMP-13) are constitutively secreted by chondrocytes in normal cartilage, but rapidly endocytosed via the cell surface endocytic receptor low-density lipoprotein receptor-related protein 1 (LRP-1) and subsequently degraded. This endocytic system is impaired in osteoarthritic (OA) cartilage due to increased ectodomain shedding of LRP-1. The aim of this study was to identify the LRP-1 sheddase(s) in human cartilage and to test whether inhibition of LRP-1 shedding prevents cartilage degradation in OA. METHODS: Cell-associated LRP-1 and soluble LRP-1 (sLRP-1) released from human cartilage explants and chondrocytes were measured by Western blot analysis. LRP-1 sheddases were identified by proteinase inhibitor profiling and gene silencing with small interfering RNAs. Specific monoclonal antibodies were used to selectively inhibit the sheddases. Degradation of aggrecan and collagen in human OA cartilage was measured by Western blot analysis using an antibody against an aggrecan neoepitope and a hydroxyproline assay, respectively. RESULTS: Shedding of LRP-1 was increased in OA cartilage compared with normal tissue. Shed sLRP-1 bound to ADAMTS-5 and MMP-13 and prevented their endocytosis without interfering with their proteolytic activities. Two membrane-bound metalloproteinases, ADAM-17 and MMP-14, were identified as the LRP-1 sheddases in cartilage. Inhibition of their activities restored the endocytic capacity of chondrocytes and reduced degradation of aggrecan and collagen in OA cartilage. CONCLUSION: Shedding of LRP-1 is a key link to OA progression. Local inhibition of LRP-1 sheddase activities of ADAM-17 and MMP-14 is a unique way to reverse matrix degradation in OA cartilage and could be effective as a therapeutic approach

Cytoplasmic tail-dependent internalization of membrane-type 1 matrix metalloproteinase is important for its invasion-promoting activity

金沢大学自然科学研究科 理化学研究所・横浜研究所　免疫アレルギー科学総合研究センター(RCAI) 横浜市立大学大学院国際総合科学研究科生体超分子科学専攻　客員教授Membrane-type 1 matrix metalloproteinase (MT1-MMP) is an integral membrane proteinase that degrades the pericellular extracellular matrix (ECM) and is expressed in many migratory cells, including invasive cancer cells. MT1-MMP has been shown to localize at the migration edge and to promote cell migration; however, it is not clear how the enzyme is regulated during the migration process. Here, we report that MT1-MMP is internalized from the surface and that this event depends on the sequence of its cytoplasmic tail. Di-leucine (Leu571–572 and Leu578–579) and tyrosine573 residues are important for the internalization, and the µ2 subunit of adaptor protein 2, a component of clathrin-coated pits for membrane protein internalization, was found to bind to the LLY573 sequence. MT1-MMP was internalized predominantly at the adherent edge and was found to colocalize with clathrin-coated vesicles. The mutations that disturb internalization caused accumulation of the enzyme at the adherent edge, though the net proteolytic activity was not affected much. Interestingly, whereas expression of MT1-MMP enhances cell migration and invasion, the internalization-defective mutants failed to promote either activity. These data indicate that dynamic turnover of MT1-MMP at the migration edge by internalization is important for proper enzyme function during cell migration and invasion

Epithelial polarization in 3D matrix requires DDR1 signaling to regulate actomyosin contractility

Epithelial cells form sheets and tubules in various epithelial organs and establish apicobasal polarity and asymmetric vesicle transport to provide functionality in these structures. However, the molecular mechanisms that allow epithelial cells to establish polarity are not clearly understood. Here, we present evidence that the kinase activity of the receptor tyrosine kinase for collagen, discoidin domain receptor 1 (DDR1), is required for efficient establishment of epithelial polarity, proper asymmetric protein secretion, and execution of morphogenic programs. Lack of DDR1 protein or inhibition of DDR1 kinase activity disturbed tubulogenesis, cystogenesis, and the establishment of epithelial polarity and caused defects in the polarized localization of membrane-type 1 matrix metalloproteinase (MT1-MMP), GP135, primary cilia, laminin, and the Golgi apparatus. Disturbed epithelial polarity and cystogenesis upon DDR1 inhibition was caused by excess ROCK (rho-associated, coiled-coil-containing protein kinase)-driven actomyosin contractility, and pharmacological inhibition of ROCK was sufficient to correct these defects. Our data indicate that a DDR1-ROCK signaling axis is essential for the efficient establishment of epithelial polarity

Development of a specific affinity-matured exosite inhibitor to MT1-MMP that efficiently inhibits tumor cell invasion in vitro and metastasis in vivo.

This is the final version of the article. It first appeared from Impact Journals via https://doi.org/10.18632/oncotarget.7780The membrane-associated matrix metalloproteinase-14, MT1-MMP, has been implicated in pericellular proteolysis with an important role in cellular invasion of collagenous tissues. It is substantially upregulated in various cancers and rheumatoid arthritis, and has been considered as a potential therapeutic target. Here, we report the identification of antibody fragments to MT1-MMP that potently and specifically inhibit its cell surface functions. Lead antibody clones displayed inhibitory activity towards pro-MMP-2 activation, collagen-film degradation and gelatin-film degradation, and were shown to bind to the MT1-MMP catalytic domain outside the active site cleft, inhibiting binding to triple helical collagen. Affinity maturation using CDR3 randomization created a second generation of antibody fragments with dissociation constants down to 0.11 nM, corresponding to an improved affinity of 332-fold with the ability to interfere with cell-surface MT1-MMP functions, displaying IC50 values down to 5 nM. Importantly, the new inhibitors were able to inhibit collagen invasion by tumor-cells in vitro and in vivo primary tumor growth and metastasis of MDA-MB-231 cells in a mouse orthotopic xenograft model. Herein is the first demonstration that an inhibitory antibody targeting sites outside the catalytic cleft of MT1-MMP can effectively abrogate its in vivo activity during tumorigenesis and metastasis.KAB was supported by a grant from the Danish Cancer Society (R40-A1838). HJD was supported in part by grants from the Danish Cancer Society, The Danish Research Council. HFK and GM were supported by Cancer Research UK and Hutchison Whampoa Ltd. HFK was also supported in part by grants from the University of Macau Start-Up Research Grant (SRG2014-00006-FHS) and Multi-Year Research Grant (MYRG2015-00065-FHS)

Effect of horizontal strong static magnetic field on swimming behaviour of Paramecium caudatum

Effect of horizontal strong static magnetic field on swimming behavior of Paramecium caudatum was studied by using a superconducting magnet. Around a center of a round vessel, random swimming at 0 T and aligned swimming parallel to the magnetic field (MF) of 8 T were observed. Near a wall of the vessel, however, swimming round and round along the wall at 0 T and aligned swimming of turning at right angles upon collision with the wall, which was remarkable around 1~4 T, were detected. It was experimentally revealed that the former MF-induced parallel swimming at the vessel center was caused physicochemically by the parallel magnetic orientation of the cell itself. From magnetic field dependence of the extent of the orientation, the magnetic susceptibility anisotropy (χ‖-χ⊥) was first obtained to be 3.4×10-23 emu cell-1 at 298 K for Paramecium caudatum. The orientation of the cell was considered to result from the magnetic orientation of the cell membrane. On the other hand, although mechanisms of the latter swimming near the vessel wall regardless of the absence and presence of the magnetic field are unclear at present, these experimental results indicate that whether the cell exists near the wall alters magnetic field effect on the swimming in the horizontal magnetic field

Impact of left ventricular assist device implantation on mitral regurgitation: An analysis from the MOMENTUM 3 trial

BACKGROUND: Mitral regurgitation (MR) determines pathophysiology and outcome in advanced heart failure. The impact of left ventricular assist device (LVAD) placement on clinically significant MR and its contribution to long-term outcomes has been sparsely evaluated. METHODS: We evaluated the effect of clinically significant MR on patients implanted in the MOMENTUM 3 trial with either the HeartMate II (HMII) or the HeartMate 3 (HM3) at 2 years. Clinical significance was defined as moderate or severe grade MR determined by site-based echocardiograms. RESULTS: Of 927 patients with LVAD implants without a prior or concomitant mitral valve procedure, 403 (43.5%) had clinically significant MR at baseline. At 1-month of support, residual MR was present in 6.2% of patients with HM3 and 14.3% of patients with HMII (relative risk = 0.43; 95% CI, 0.22-0.84; p = 0.01) with a low rate of worsening at 2 years. Residual MR at 1-month post-implant did not impact 2-year mortality for either the HM3 (hazard ratio [HR],1.41; 95% CI, 0.52-3.89; p = 0.50) or HMII (HR, 0.91; 95% CI, 0.37-2.26; p = 0.84) LVAD. The presence or absence of baseline MR did not influence mortality (HM3 HR, 0.86; 95% CI, 0.56-1.33; p = 0.50; HMII HR, 0.81; 95% CI, 0.54-1.22; p = 0.32), major adverse events or functional capacity. In multivariate analysis, severe baseline MR (p = 0.001), larger left ventricular dimension (p = 0.002), and implantation with the HMII instead of the HM3 LVAD (p = 0.05) were independently associated with an increased likelihood of persistent MR post-implant. CONCLUSIONS: Hemodynamic unloading after LVAD implantation improves clinically significant MR early, sustainably, and to a greater extent with the HM3 LVAD. Neither baseline nor residual MR influence outcomes after LVAD implantation