Hydroxyapatite [Ca10(PO4)6(OH)2; HAp] is the mineral component of vertebrate hard tissues and an important raw material for biomaterials. The HAp crystal belongs to a hexagonal system and has two types of crystal plane with different atomic arrangements: positively charged calcium ions are mainly present in the a(b)-planes, while negatively charged phosphate ions and hydroxyl groups are mainly present in the c-planes. In vertebrate long bone surfaces, HAp crystals have a c-axis orientation, which leads to the development of the a(b)-plane; while in tooth enamel surfaces, they have an a(b)-axis orientation, which leads to the development of the c-plane. However, it is not clear why the orientations of long bone and tooth enamel are in different crystal planes. In order to clarify this question, we have synthesized single-crystal apatite particles with preferred orientation to the a- and c-axes as models for bone and teeth enamel. This review first describes the syntheses process of single-crystal apatite particles with preferred orientation to a(b)- and c-axes and then discusses specific protein adsorption to the crystal surface of the resulting plate- and fiber-shaped apatite particles with different surface charges. In addition, porous apatite-fiber scaffolds (AFSs) fabricated using the fiber-shaped apatite particles and their application to tissue engineering of bone are described on the basis of the three-dimensional cell culture of mesenchymal stem cells derived from rat bone marrow using the AFS settled into a radial-flow bioreactor.
With the global rise in aging of populations, the occurrence of osteoporosis will continue to increase. Biomaterial and pharmaceutical scientists continue to develop innovative strategies and materials to address this disease. In this article, we describe a new perspective and approach into the use of coral exoskeletons as a precursor material to synthesize a calcium phosphate-based drug delivery system. Studies detailing the methodology of the conversion methods and the strategies and approach for the development of these novel drug delivery systems are described. Furthermore, in vivo studies in osteoporotic mice using a drug loaded and chemically modified version of the biomimetic delivery system showed significant cortical and cancellous bone increases. These studies support the notion and the rationale for future research and development of the use of coral exoskeletons as materials for drug delivery applications.
Our group has succeeded to synthesize material with bone-like nanostructure and bone-like inorganic and organic composition via self-organization mechanism between them using simultaneous titration method under controlled pH and temperature. The hydroxyapatite/collagen (HAp/Col) bone-like nanocomposite completely incorporated into bone remodeling process to be substituted by new bone. Cells cultured on the HAp/Col revealed very interesting reactions. Osteoblast-like MG63 cells showed upregulation of alkaline phosphatase >3 times greater than MG63 cells cultured on tissue culture polystyrene (TCPS). MG63 cells 3-dimensionally cultured in a “HAp/Col sponge,” a porous HAp/Col having sponge-like viscoelasticity, accumulated calcium phosphate nodules on extracellular matrices they secreted. Bone marrow cells co-cultured with osteoblasts on HAp/Col differentiated to osteoclasts without differentiation supplements. This phenomenon is not found in cells cultured on hydroxyapatite ceramics and TCPS, and rarely in cells cultured on dentin. These results suggest that HAp/Col is a good candidate for tissue engineering of bone as well as bone filler. In a clinical test as a bone filler, the HAp/Col sponge was significantly better than porous β-tricalcium phosphate. The HAp/Col sponge has been approved by the Japanese government and will be used as greatly needed bone filler in patients. In addition to the above, HAp/Col coating on titanium revealed higher osteoconductivity than HAp-coated titanium and bare titanium and improved direct bonding between titanium and newly formed bone. The HAp/Col coating may be used for metal devices requiring osseointegration.
Several varieties of ceramics, such as Bioglass-type glasses, sintered hydroxyapatite and glass-ceramic A–W, exhibit specific biological affinity, i.e., direct bonding to surrounding bone, when implanted in bony defects. These bone-bonding ceramics are called bioactive ceramics and are utilized as important bone substitutes in the medical field. However, there is a limitation to their clinical applications because of their inappropriate mechanical properties. Natural bone takes a kind of organic–inorganic composite, where apatite nanocrystals are precipitated on collagen fibers. Therefore, problems with the bioactive ceramics can be solved by material design based on the composites. In this paper, current research topics on the development of bioactive organic–inorganic composites inspired by actual bone microstructure have been reviewed in correlation with preparation methods and various properties. Several kinds of inorganic components have been found to exhibit bioactivity in the body environment. Combination of the inorganic components with various organic polymers enables the development of bioactive organic–inorganic composites. In addition, novel biomedical applications of the composites to drug delivery systems, scaffolds for tissue regeneration and injectable biomaterials are available by combining drugs or biological molecules with appropriate control of its microstructure.
Calcium phosphate (CaP)-based compounds are biocompatible and have been accepted as promising candidates for novel drug-releasing devices. CaP is biodegradable and can be utilized as a durable drug release reservoir. We developed an injectable self-setting apatite cement. When a plasmid DNA complex containing CaP was injected into tumor-bearing mice, it solidified in the body and slowly released the DNA complex, inducing durable gene expression and high therapeutic effect on solid tumors. Encapsulation of a drug by CaP acts as a protective capsule for the unstable contents and improves biocompatibility. CaP nanocapsules encapsulating a plasmid DNA complex or drug-involved micelle were prepared, and they showed high stability against enzyme and protein degradation. CaP also showed high potential as a durable acid pH buffer. Aqueous alginate solution was found to form a soft gel in the body and was investigated as a drug-releasing device. However, degradation of the alginate gel is sometimes too rapid in an acidic environment such as the area around osteoporotic bones. We found that amorphous CaP powder added to the alginate gel could control the dissociation rate, buffering the pH inside the gel. Alginate gel including CaP powder and a drug for osteoporosis allowed sustained release of the drug under acidic conditions, and a good therapeutic effect was achieved in osteoporosis model rats. CaP could thus be a valuable material for drug-delivery systems as a slow-releasing drug reservoir, a protective coating, or a pH buffer.
Organic–inorganic hybrids of poly(dimethyl siloxane), gelatin, and chitosan with such silanes as tetraethoxysilane and 3-glycidoxytriethoxysilane are derived via the sol–gel routes. Their biomedical applications are discussed from biomimetic deposition of bone-like apatite, cell culture, and in vivo behavior.
Vesicular nucleotide transporter (VNUT) is responsible for vesicular ATP storage in ATP-secreting cells. In the present study, we examined the effects on VNUT-mediated transport of ATP release inhibitors such as ATP-binding cassette (ABC) proteins, hemichannels, maxi anion channels and P2X7 receptor. The ATP transport activity of proteoliposomes containing purified human VNUT was blocked by glibenclamide, carbenoxolone, 18 α-glycyrrhetinic acid, flufenamic acid, arachidonic acid and A438079 without the formation of Δψ (positive inside) as a driving force being affected. Thus, inhibitors of ATP release may inhibit VNUT and subsequent ATP release, since the previous works proved that inhibitors of ATP release blocked VNUT-mediated ATP release at the cell level.
The aim of this study was to identify the effects of 85% methanolic extract of Morus alba leaves (EMA), which is a traditional herb, in mice. The effects of EMA on the anxiolytic-like behaviour were studied using the elevated plus maze (EPM) and hole-board test. To elucidate the mode of action of the anxiolytic-like effects of EMA, the mice were subjected to the co-administration of EMA (200 mg/kg, per os (p.o.)) and either antagonist. EMA (at 200 or 400 mg/kg) significantly increased the percentages of time-spent in the open arms and entries into the open arms of the EPM versus vehicle-treated control group (p<0.05). Moreover, in the hole-board test, EMA (200 and 400 mg/kg) significantly increased the number of head-dips versus vehicle-treated control group (p<0.05). However, there were no changes in the locomotor activity and myorelaxant effects in any group compared with the vehicle-treated control group. In addition, the anxiolytic-like effects of EMA were abolished by thioperamide (10 mg/kg, intraperitoneally (i.p.)), which is a histamine H3 receptor antagonist. Moreover, results from reverse transcription polymerase chain reaction (RT-PCR) also revealed that the amygdalal histidine decarboxylase mRNA expression levels in EMA (200 mg/kg)-treated group were significantly higher than those in the vehicle-treated controls (p<0.05). These results suggest that EMA might prove to be an effective anxiolytic agent and that EMA acts via the histaminergic system in central nerve system.
Metabolomics is a new platform based on the comprehensive analysis of low molecular weight metabolites and provides a powerful approach to discover biomarkers in biological systems. Modified Sinisan (MSNS), a traditional Chinese medicine formula, displayed bright prospects in the prevention and therapy of liver injury. However, its molecular mechanism of hepatoprotective effects remains unclear. This paper was designed to explore the effects and potential mechanisms of MSNS against dimethylnitrosamine-induced liver injury. Global metabolic profiling was performed by ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC/ESI-Q-TOF-MS) in conjunction with multivariate data analysis and pathway analysis. Eleven serum biomarkers were identified and pathway analysis results showed that phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism, tryptophan metabolism, retinol metabolism, tyrosine metabolism were perturbed by liver injury. More importantly, MSNS has showed satisfactory pharmacological effect on liver injury through partially regulating the perturbed pathways, correlates well to the biochemical and histopathological detection results. The present study proved that the robust metabolomics approach is promising for unraveling hepatoprotective effects of MSNS and these findings provide new insights into mechanisms of the liver injury, and its pathophysiologic processes.
Curcumin has various biological activities including antioxidant and antiinflammatory actions, and alcohol detoxification. However, because of its poor absorption efficiency, it is difficult for orally administered curcumin to reach blood levels sufficient to realize its bioactivities. We have generated capsules and tablets containing Theracurmin, a highly absorptive curcumin. In addition, we recently created a drinkable preparation of Theracurmin. To evaluate the absorption efficiency of this type of curcumin, we performed a single-dose, double-blind, 4-way crossover study. We compared plasma curcumin levels after the administration of Theracurmin beverage and 3 other drinkable types of curcumin sold in Japan. Twenty-four healthy subjects (male/female=13/11, age: 23–32) were administered with these 4 drinkable preparations of curcumin. The area under the blood concentration–time curve at 0–8 h was found to be 1.5 to 4.0-fold higher with Theracurmin than with the other 3 kinds of curcumin beverage. Moreover, maximal plasma curcumin concentrations (0–8 h) of Theracurmin were 1.8 to 3.8 times higher than those of the other 3 curcumin beverages. These data indicate that our newly prepared Theracurmin beverage exhibits a much better absorption efficiency than other kinds of curcumin beverage sold in Japan.
Human cytomegalovirus (CMV) is the most common cause of viral intrauterine infection in developed countries. It has been shown that CMV DNA was frequently detected in the fetal membranes when the placenta was infected in utero. However, it is still not clear whether CMV replicates in constituent cells of the fetal membranes. We investigated CMV infection of primary cultured chorion and amnion cells prepared from human fetal membrane tissues. In both types of cell cultures, rounded cells were observed at day 8 and 12 after CMV inoculation, and virus yields in culture supernatants were increased after the inoculation. In both types of cells, viral immediately early 1 (IE1) protein-positive nuclei were scattered at day 4 after the inoculation, and IE1 mRNA was expressed throughout day 1 to 12 after CMV inoculation. In chorion cell cultures, the number of IE1 protein-positive nuclei increased significantly at day 8 and 12 after CMV inoculation as compared to day 4, by which foci were formed. Furthermore, an evident increase in levels of lactate dehydrogenase leakage from chorion cells was observed after CMV inoculation. Contrary, these phenomena were not observed in amnion cell cultures. These results demonstrated that both chorion and amnion cells were permissive to CMV infection, while the velocity of cell-to-cell spread of CMV infection in amnion cells was much lower than that in chorion cells. Therefore, the present study suggests that CMV may replicate rapidly in the chorion cell layer and slowly in the amnion cell layer during intrauterine infection.
Hydroquinone (HQ) is a chemical compound that inhibits the functions of melanocytes and has long been known for its skin-whitening effect. According to previous studies, the Tyrosinase (Tyr) activity inhibitory effect and melanocyte-specific cell toxicity are known depigmenting mechanisms; however, details of the underlying mechanisms are unknown. Arbutin (Arb) is also known for its Tyr activity inhibitory effect and is commonly used as a skin-whitening agent. However, the detailed depigmenting mechanism of Arb is also not yet fully understood. Few studies have attempted to elucidate the effects of HQ and Arb on undifferentiated melanocytes. In this study, we examined the effects of HQ and Arb throughout each stage of differentiation of melanocytes using a mouse embryonic stem cell (ESC) culture system to induce melanocytes. The results showed that HQ in particular downregulated the early stage of differentiation, in which neural crest cells were generated, and the late stage of differentiation, in which melanogenesis became active. On the other hand, Arb had no effect on the differentiation of melanocytes, and only suppressed melanogenesis by specifically suppressing elevations in Tyr expression in the late stage of differentiation.
Artificial introduction of functional molecules on the cell surface may be a promising way to improve the therapeutic effects of cell therapy. Pegylated lipids are conventionally used in drug carriers. The lipid part of pegylated lipids noncovalently interacts with the cell surface. However, little information is available regarding conditions for cell-surface modification by using pegylated lipids. In this study, we synthesized fluorescein-labeled pegylated lipids and evaluated the factors that affect modification efficiency by using human mesenchymal stem cells (hMSCs). As the concentration of the pegylated lipid as well as the exposure time increased, the modification efficiency increased. The modification efficiency at 37°C was 20- and 3-fold higher than that at 4°C and 25°C, respectively. In addition, with an increase in the molecular weight of polyethylene glycol (PEG), more pegylated lipids were extracellularly distributed than those intracellularly distributed. At the optimal condition, pegylated lipids were observed mainly on the cell membrane by confocal microscopy. In contrast, the cell condition (adherent or nonadherent) had little or no effect on the cell-surface modification efficiency. The results of this study will be useful for constructing an optimal modification method for introducing functional molecules on the cell surface.
Fingolimod (FTY720) is known to have a significant therapeutic effect in various autoimmune disease models. Here, we examined FTY720 in a model of rheumatoid arthritis, induced by immunizing DBA/1 mice with a peptide consisting of residues 325 through 339 of glucose-6-phosphate isomerase (GPI325–339). The efficacy was evaluated in terms of macroscopic findings, inflammatory cell infiltration and autoantibody level. Prophylactic administration of FTY720 from the day of immunization significantly suppressed the development of paw swelling, but therapeutic administration of FTY720 from onset of symptoms on day 8–9 was less effective. Interestingly, however, combination treatment with FTY720 plus GPI325–339 for 5 d after onset of symptoms significantly reduced the severity of symptoms in all mice, and no relapse occurred after booster immunization. Taking into account the reported mechanism of action of FTY720, these results indicate that combination treatment with FTY720 plus pathogenic autoantigen might efficiently induce immune tolerance by sequestering circulating autoantigen-specific lymphocytes from blood and peripheral tissues to the secondary lymphoid tissues. Combination treatment with FTY720 plus pathogenic autoantigen may become a breakthrough treatment for remission-induction in patients with autoimmune diseases including rheumatoid arthritis.
The oral consumption of capsicum has been reported to increase interleukin (IL)-2 and interferon (IFN)-γ production in Peyer’s patches (PP); however, the active components responsible for these effects have not been completely identified. The beneficial biological effects of green peppers cultivated under environmentally friendly farming conditions (ECP), without the use of chemical pesticides, have rarely been compared with those of green peppers cultivated under conventional farming conditions (CCP). Oral administration of ECP extract significantly induced the production of IL-2 and IFN-γ in concanavalin A-treated cells from PP ex vivo; their levels were much higher than those in the CCP extract-treated group. A comparative analysis of the HPLC profiles indicated a 1.7-fold increase of a peak, named EF-1, at 415 nm in the ECP extract. The major component of EF-1 was identified as pheophytin a, which is a chlorophyll a molecule lacking a central Mg2+ ion, as determined from NMR data. Intake of pheophytin a and chlorophyll a significantly increased IL-2 and IFN-γ production, and the percentage of IL-2- and IFN-γ-producing CD4+ T-cells in PP. Taken together, our data suggest that ECPs produce a higher content of pheophytin a than CCPs, and pheophytin a and chlorophyll a are immune-modulating components in green vegetables.
G-protein coupled receptor 43 (GPR43) serves as a receptor for short-chain fatty acids (SCFAs), implicated in neutrophil migration and inflammatory cytokine production. However, the intracellular signaling pathway mediating GPR43 signaling remains unclear. Here, we show that β-arrestin 2 mediates the internalization of GPR43 by agonist. Agonism of GPR43 reduced the phosphorylation and nuclear translocation of nuclear factor-κB (NF-κB), which was relieved by short interfering RNA (siRNA) of β-arrestin 2. Subsequently, mRNA expression of proinflammatory cytokines, interleukin (IL)-6 and IL-1β, was downregulated by activation of GPR43 and knockdown of β-arrestin 2 recovered the expression of the cytokines. Taken together, these results suggest that GPR43 may be a plausible target for a variety of inflammatory diseases.
Skin has various types of transporters and is a biochemically active organ. These aspects of skin influence the distribution of chemicals in skin and their elimination from skin. The biochemical and histological variations of the skin must be taken into account when conducting transdermal penetration research. Here we used hairless mouse skin to investigate the percutaneous absorption of chemicals in vitro from the stratum corneum (SC) side to the viable skin (VS) side (forward direction) and from the VS side to the SC side (backward direction). We examined the effects of molecular weight, lipophilicity (Log Ko/w), electric charge, and the molecular structure of penetrants. The penetration flux of verapamil hydrochloride (VRP) for the backward direction was 3.2 times larger than that for the forward direction. The flux values of benzoic acid (BA) and para-hydroxybenzoic acid (pHBA) for the forward direction were 2.1 and 4.6 times larger than those for the backward direction, respectively. This directional difference was caused by the active transporter for VRP, the histological distribution of BA solubility, and the intermolecular hydrogen bonding between pHBA and skin tissue in the stripped skin. Across intact skin, in contrast, there was no difference in the skin penetration profile between the forward direction and backward directions.
Fat-specific protein 27 gene (FSP27), isolated by screening for genes specifically expressed in fully differentiated mouse adipocytes, belongs to the cell death-inducing DNA fragmentation factor, alpha subunit-like effector family. FSP27 is induced in not only adipose tissue but also the liver of ob/ob mice, and it promotes the development of fatty liver. The FSP27 gene is expressed in a fatty liver-specific manner and is not detected in the normal mouse liver. FSP27 expression is directly regulated by the induction of the hepatic peroxisome proliferator-activated receptor γ (PPARγ) in ob/ob fatty liver. In the present study, expression of hepatic FSP27 mRNA was determined in non-genetic fatty liver models. The FSP27 gene was markedly induced in the high-fat- or methionine- and choline-deficient (MCD) diet-induced fatty liver, but it was not elevated in alcohol-induced fatty liver. Interestingly, the induction of FSP27 mRNA due to the MCD diet was independent of PPARγ levels and completely absent in the liver from PPARγ-null mice. These results suggest that FSP27 mRNA expression in the liver depends on the etiology of fatty liver.
Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L., shows potent antioxidant property. Herein, we investigated the protective effects of salidroside against hydrogen peroxide (H2O2)-induced oxidative damage in human endothelial cells (EVC-304). EVC-304 cells were incubated in the presence or absence of low steady states of H2O2 (3–4 µM) generated by glucose oxidase (GOX) with or without salidroside. 3(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) assays were performed, together with Hoechst 33258 staining and flow cytometric analysis using Annexin-V and propidium iodide (PI) label. The results indicated that salidroside pretreatment attenuated endogenous H2O2 induced apoptotic cell death in EVC-304 cells in a dose-dependent pattern. Furthermore, Western blot data revealed that salidroside inhibited activation of caspase-3, 9 and cleavage of poly(ADP-ribose) polymerase (PARP) induced by endogenous H2O2. It also decreased the expression of Bax and rescued the balance of pro- and anti-apoptotic proteins. All these results demonstrated that salidroside may present a potential therapy for oxidative stress in cardiovascular and cerebrovascular diseases.
Excessive osteoclastic bone resorption plays a critical role in inflammation-induced bone loss such as rheumatoid arthritis and periodontal bone erosion. Therefore, identification of osteoclast targeted-agents may be a therapeutic approach to the treatment of pathological bone loss. In this study, we isolated chlorogenic acid (CGA) from fructus of Gardenia jasminoides to discover anti-bone resorptive agents. CGA is a polyphenol with anti-inflammatory and anti-oxidant activities, however, its effects on osteoclast differentiation is unknown. Thus, we investigated the effect of CGA in receptor activator of nuclear factor-kappa B (NF-κB) ligand (RANKL)-induced osteoclast differentiation and RANKL signaling. CGA dose-dependently inhibited RANKL-mediated osteoclast differentiation in bone marrow macrophages (BMMs) without any evidence of cytotoxicity. CGA inhibited the phosphorylation of p38, Akt, extracellular signal-regulated kinase (ERK), and inhibitor of nuclear factor-kappa B (IκB), and IκB degradation by RANKL treatment. CGA suppressed the mRNA expression of nuclear factor of activated T cells c1 (NFATc1), TRAP and OSCAR in RANKL-treated bone marrow macrophages (BMMs). Also, overexpression of NFATc1 in BMMs blocked the inhibitory effect of CGA on RANKL-mediated osteoclast differentiation. Furthermore, to evaluate the effects of CGA in vivo, lipopolysaccharide (LPS)-induced bone erosion study was carried out. CGA remarkably attenuated LPS-induced bone loss based on micro-computed tomography and histologic analysis of femurs. Taken together, our findings suggest that CGA may be a potential treatment option for osteoclast-related diseases with inflammatory bone destruction.
Oxaliplatin, which is used as one of anti-cancer drugs, commonly induces peripheral neuropathic pain. We have previously reported that an injection of diluted bee venom (DBV) produced a significant anti-nociceptive effects in several pain models of mice or rats. In this study, we evaluated time- and dose-dependent development of oxaliplatin-induced mechanical allodynia in bilateral hind paws of mice, and investigated the effect of DBV injection on this mechanical allodynia. DBV (0.1 mg/kg) was subcutaneously injected into the Zusanli acupoint 2 weeks after oxaliplatin (10 mg/kg) injection. One hour after DBV injection, we observed a significant reduction of mechanical allodynia in the ipsilateral hind paw, but not in the contralateral hind paw to DBV injection site. We subsequently examined whether this effect of DBV was related to the activation of peripheral nerves in DBV injected site, and then whether it was mediated by the activation of spinal cord alpha-2 adrenoceptors or opioid receptors. Subcutaneous pre-injection of 2% lidocaine (40 mg/kg) into the Zusanli acupoint completely blocked the anti-allodynic effect of DBV. Intrathecal pretreatment with yohimbine (25 µg/mouse), an alpha-2 adrenoceptor antagonist, also prevented the anti-allodynic effect of DBV, whereas pretreatment with naloxone (20 µg/mouse), an opioid receptor antagonist, did not block the effect of DBV. Taken together, these findings demonstrate that DBV injection into the Zusanli acupoint significantly reduces ipsilateral mechanical allodynia generated by oxaliplatin in mice, and also suggest that this anti-allodynic effect is dependent on the peripheral nerve activation in injected site and spinal cord alpha-2 adrenoceptors.
The purpose of the present study was to investigate the usefulness of the ternary complex with protamine and γ-polyglutamic acid (γ-PGA), which are biodegradable materials for foods and medical products, as a safe gene delivery vector. We formed cationic binary complexes (plasmid DNA (pDNA)/protamine complexes) with high transfection efficiency. The binary complex showed slight toxicity probably related to its total cationic charge. Then, we formed ternary complexes (pDNA/protamine/γ-PGA complexes) by addition of anionic polymer, γ-PGA, and they showed no cytotoxicity. The transfection efficiency of the pDNA/protamine/γ-PGA complexes was as high as that of the pDNA/protamine complexes, although their zeta potentials were different. Inhibition study of the gene expressions in B16-F10 cells suggested that pDNA/protamine complexes were taken up by caveolae-mediated endocytosis and macropinocytosis. On the other hand, pDNA/protamine/γ-PGA complexes were taken up by clathrin-mediated endocytosis and macropinocytosis. Thus, we succeeded in developing the ternary complex as a safe gene delivery vector with biocompatible materials.
In this experiment, we developed a novel safe and effective gene delivery vector coated with γ-polyglutamic acid (γ-PGA-coated complexes). The γ-PGA-coated complex was composed of chiseled spherical nano-particles with anionic charges. The plasmid DNA/polyethyleneimine complex (non-coated complex) showed high transgene efficiency in the spleen and lung after intravenous administration in mice, with high liver toxicity and lethality. On the other hand, γ-PGA-coated complex selectively showed high transgene efficiency in the spleen without such toxicity. Furthermore, the γ-PGA-coated complex highly accumulated and showed high gene expression in the marginal zone of the spleen. Those results strongly indicated that γ-PGA-coated complex was suitable as a DNA vaccine vector. We therefore applied γ-PGA-coated complex to melanoma DNA vaccine, pUb-M. The γ-PGA-coated complex containing pUb-M significantly inhibited the growth and metastasis of a melanoma cell line, B16-F10 cells. In conclusion, we developed a splenic gene vector, γ-PGA-coated complex, as a novel technology for clinical vaccination.
We analyzed the effect of serum and fibronectin on pulmonary transgene expression after intravenous injection of cationic liposome–plasmid DNA (pDNA) complex (lipoplex) in mice. 1,2-Dioleoyl-3-trimethylammonium-propane (DOTAP) methyl sulfate salt/cholesterol lipoplex was incubated with several serum components for 5 min at 37°C prior to injection. We analyzed pulmonary transgene expression and pulmonary accumulation of lipoplex. While interaction with serum did not decrease pulmonary transgene expression, interaction with heat-inactivated serum did decrease it. Moreover, interaction with fibronectin enhanced pulmonary transgene expression. Inhibition of the binding of fibronectin to integrin decreased pulmonary transgene expression after injection of untreated lipoplex. We found that pulmonary accumulation of lipoplex changed depending on the kind of interacting serum components after injection. Furthermore, interaction with fibronectin increased pulmonary accumulation of lipoplex. Interaction with serum was required for pulmonary gene transfer following intravenous injection of lipoplex. Fibronectin appears to be a particularly critical component. Furthermore, the binding of fibronectin interacting with lipoplex to integrin was an important mechanism for pulmonary transgene expression.
Association between cytochrome P450 (CYP) 3A4*1G genotype of donors (n=412) and/or recipients (n=410), and the pharmacokinetics of tacrolimus and the risk of acute cellular rejection was examined in Japanese living-donor liver transplant patients between 2004 and 2011. The concentration/dose (C/D) ratio of tacrolimus in patients carrying graft liver with CYP3A4*1/*1 was significantly higher during 7 d after surgery than in that with CYP3A4*1/*1G (214 vs. 157 [ng/mL]/[mg/kg/day], p<0.01). After postoperative day 8, no significant difference was observed among CYP3A4*1G genotypes in the graft liver. However, the C/D ratio in CYP3A4*1/*1 of the intestine was significantly higher than that in CYP3A4*1G/*1G for 5 weeks after surgery (postoperative days 1–14; p<0.001, postoperative days 15–35; p<0.01). During postoperative days 14 and 26, acute cellular rejection incidences tended to be lower in the patients with graft liver carrying the CYP3A4*1/*1 allele than in the patients carrying CYP3A4*1G allele (8.7% vs. 14.6%, p=0.0973). However, CYP3A4*1G in the intestine had almost no effect on the incidence of rejection (9.9% in CYP3A4*1/*1vs. 12.5% in CYP3A4*1G allele, p=0.4824). CYP3A4*1G was significantly related to mRNA expression of CYP3A5 rather than of CYP3A4 in the graft liver and intestine and was strongly linked with the CYP3A5*1. Thus, we elucidated that CYP3A4*1G genotype in the intestine was an important indicator of the pharmacokinetics of tacrolimus, whereas this genotype in the graft liver tended to influence the frequency of acute cellular rejection after transplantation.
Previously, we reported that repeated oral administration of etoposide (ETP) increases P-glycoprotein (P-gp) expression in association with activation of ezrin/radixin/moesin (ERM) in the small intestine. Radixin has recently attracted attention for its critical role in the plasma membrane localization of certain drug transporters including P-gp by working as a scaffold protein. However, there have been no report investigating that radixin really interacts with small intestinal P-gp and is involved in the mechanism by which the levels of P-gp are altered. Here, we examined whether radixin is involved in the increased P-gp expression in the small intestine after ETP treatment. Repeated oral treatment with ETP (10 mg/kg/day) for 7 d significantly increased ERM proteins bound to P-gp in the small intestine as determined by immunoprecipitation analysis. In particular, radixin but not ezrin or moesin bound to P-gp was dramatically increased in association with the up-regulation of P-gp in the small intestinal membrane, and radixin was highly co-localized with P-gp as measured by immunofluorescence analysis. In conclusion, radixin may contribute, at least in part, to an increase in the expression of the small intestinal P-gp upon induction with repeated oral treatment with ETP.
To clarify whether peripheral inflammation has a remote effect on the central nervous system, the electrolyte disposition between the circulating blood and central nervous system was evaluated in rats with carrageenan-induced acute peripheral inflammation (API). λ-Carrageenan was subcutaneously injected in the hind paw of the rat, and lithium was utilized as a surrogate marker of sodium. When the plasma and cerebrospinal fluid (CSF) concentrations of lithium were examined following lithium being intravenously administered, it was revealed that the CSF concentration of lithium in API rats is reduced compared to that in normal rats, while the plasma concentration profile of lithium in API rats is indistinguishable from that in normal rats. The pharmacokinetic analysis showed that the lithium disposition from the plasma to CSF markedly decreased by 35.8% in API rats compared to that in normal rats. On the other hand, when lithium was immediately administered into the lateral ventricle, its elimination profiles in CSF were not different between normal and API rats. It is therefore probable that the lithium disposition from the plasma to CSF alters in API rats, reflecting the entry process of electrolytes from the circulating blood to brain tissue being suppressed in response to peripheral inflammation.
The characteristics of bacteria take up mercury into cells via membrane potential-dependent sequence-divergent members of the mercuric ion (Mer) superfamily, i.e., a periplasmic mercuric ion scavenging protein (MerP) and one or more inner membrane-spanning proteins (MerC, MerE, MerF, and MerT), which transport mercuric ions into the cytoplasm, have been applied in engineering of bioreactor used for mercurial bioremediation. We engineered bacteria to express MerC, MerE, MerF, or MerT with or without MerP to clarify their individual role and potential in transport of mercurial. By immunoblot analysis using specific polyclonal antibody, the proteins encoded by merC, merE, merF, merT or merP, were certainly expressed and identified in the membrane fraction. Bacteria expressing MerC, MerE, MerF or MerT in the absence of MerP transported significantly more C6H5Hg(I) and Hg(II) across bacterial membrane than their isogenic strain. In vivo expression of MerP in the presence of all the transporters did not cause apparent difference to the C6H5Hg(I) transport, but gives an apparently higher Hg(II) transport than that did by MerE, MerF or MerT but not by MerC. Among the four transporters studied, MerC showed more potential to transport Hg(II) across bacterial membrane than MerE, MerF and MerT. Together these findings, we demonstrated for the first time that in addition to MerE and MerT, MerF and MerC are broad-spectrum mercury transporters that mediate both Hg(II) and phenylmercury transport into cells. Our results suggested that MerC is the most efficient tool for designing mercurial bioremediation systems, because MerC is sufficient for mercurial transport into cells.
We have reported that PEGylated liposomes lose their long-circulating properties when injected twice into the same animal within a certain interval (the accelerated blood clearance (ABC) phenomenon). We assumed that this phenomenon was triggered via the abundant secretion of anti-polyethylene glycol (PEG) immunoglobulin M (IgM) in response to the first dose of PEGylated liposomes and that the spleen played an important role in the production of anti-PEG IgM. However, no direct evidence has yet confirmed this suspicion. In the current study, we verified, both in vitro and ex vivo, that spleen cells are indeed responsible for the production of anti-PEG IgM in response to PEGylated liposomes. In this study, spleen cells obtained from either naïve mice or mice pre-treated with PEGylated liposomes induced the production of anti-PEG IgM in a dose- and time-dependent manner, upon incubation with PEGylated liposomes. In addition, we confirmed that among the different fractions of splenic B cells, IgM-positive B cells, rather than CD45R-positive or CD19-positive splenic B cells, which are presumed to be the marginal zone B (MZB) cells, are the major cells producing anti-PEG IgM in the response to stimulation by PEGylated liposomes. These results may provide new insights into the mechanisms underlying the anti-PEG IgM production in response to the stimulation by PEGylated liposomes.
Hyperosmotic stress induces the contractile response of vascular smooth muscle cells (VSMCs). Previous studies have demonstrated that cytoskeleton reorganization and Rho/Rho-kinase-mediated inactivation of myosin light chain phosphatase (MLCP) play an important role in hyperosmotic vasoconstriction, but the precise mechanism is unknown. This study aimed to investigate the contractile response of endothelium-denuded rings of rat aortas to hyperosmolar sucrose (160 mM) in the presence or absence of inhibitors for various protein kinases. We found that the hyperosmotic constriction of aortic rings was attenuated not only by ML-7 or hydroxyfasudil, specific inhibitor for myosin light chain kinase (MLCK) or Rho-kinase, respectively, but also by SB203580, a specific inhibitor for p38 mitogen-activated kinase (p38 MAPK). Hyperosmolar sucrose evoked a transient increase in cytosolic free Ca2+ in rat VSMCs, and this response was not affected by SB203580. Western blot analysis of proteins extracted from rings showed that the hyperosmolar sucrose stimulated phosphorylation of the Rho-kinase-mediated myosin phosphatase target subunit 1, myosin light chain (MLC), and p38 MAPK. The experiments performed using a combination of the kinase inhibitors showed that hyperosmolarity-induced MLC phosphorylation is partially mediated via the SB203580-sensitive pathway and is independent of both MLCK and Rho-kinase-mediated inactivation of MLCP. Furthermore, the hyperosmolarity-induced increase in the F-actin/G-actin ratio in rings was attenuated not only by hydroxyfasudil but also by SB203580. These results suggest that p38 MAPK is involved in hyperosmotic vasoconstriction via stimulation of MLC phosphorylation and cytoskeleton reorganization through pathways independent of activation of MLCK and/or Rho-kinase-mediated mechanisms.
Flow injection spectrophotometric analysis (FIA) of human salivary α-amylase was developed using an enzyme degradation reaction of starch–iodine complexes. In this proposed method, the salivary α-amylase, known as a human stress indicator, is directly and rapidly determined without any pretreatment. In this study, the optimum starch–iodine complexes (i.e., optimum molecular weight and amylase–amylopectin compounding ratio) were selected, and their rapid degradation in the flow channel was investigated to determine salivary amylase in the FIA system. The determination range of α-amylase was obtained from 0.25 to 5.0 kilo Novo unit per milliliter (KNU/mL), and these concentrations were equivalent to the real concentration of amylase in human saliva. The quantitative values obtained by this method were found to be highly reproducible with 1.6% (n=25) of the relative standard deviation for 1.0 KNU/mL. The detection limit (3σ) was 60 NU/mL. In addition, the method requires small volume of a sample (20 µL), and 30 samples was sequentially measured within one hour. Real human saliva collected before and after exercise was utilized to demonstrate the feasibility of human stress test and analytical performance of this approach.
We applied a parallel pore permeation model based on the Renkin molecular sieving function by using two different-sized pathways to analyze the permeation-enhancing effects of poly-L-arginine (PLA) or a mixed system of spermine (SPM) and sodium taurocholate (STC). Four paracellular markers were simultaneously applied to Caco-2 cell monolayers, and a set of apparent permeability coefficient (P) values was used to obtain membrane parameters. For PLA treatment, the pore occupancy/length ratio (ε/L) of the large pathways increased while the pore radius (R) did not, suggesting that the number of large pathways for the relatively large hydrophilic molecules in the monolayers could be increased by the addition of PLA. In contrast, application of the mixed system comprising SPM and STC significantly increased not only the R of the large pathways but also ε/L of the small pathways. Such changes in membrane parameters could be related to the enhancing mechanism of these compounds. The simulation curves for molecular weight (MW)-P calculated from the membrane parameters could be used to predict the P of drugs with different MWs.
In this study, we evaluated a baculoviral display system for analysis of viral entry by using a recombinant adenovirus (Ad) carrying a luciferase gene and budded baculovirus (BV) that displays the adenoviral receptor, coxsackievirus and adenovirus receptor (CAR). CAR-expressing B16 cells (B16-CAR cells) were infected with luciferase-expressing Ad vector in the presence of BV that expressed or lacked CAR (CAR-BV and mock-BV, respectively). Treatment with mock-BV even at doses as high as 5 µg/mL failed to attenuate the luciferase activity of B16-CAR cells. In contrast, treatment with CAR-BV with doses as low as 0.5 µg/mL significantly decreased the luciferase activity of infected cells, which reached 65% reduction at 5 µg/mL. These findings suggest that a receptor-displaying BV system could be used to evaluate viral infection.