Protection of neurons from neuronal damage and cell death in neurodegenerative disease is a major challenge in neuroscience research. Donepezil, galantamine and tacrine are acetylcholinesterase inhibitors used for the treatment of Alzheimer's disease, and were believed to be symptomatic drugs whose therapeutic effects are achieved by slowing the hydrolysis of acetylcholine at synaptic termini. However, recent accumulated evidence strongly suggests that these acetylcholinesterase inhibitors also possess neuroprotective properties whose mechanism is independent of acetylcholinesterase inhibition. We have shown that acetylcholinesterase inhibitors protect neurons from glutamate-induced neurotoxicity in the primary culture of rat cortical neurons. It was also found that acetylcholinesterase inhibitor treatment induces up-regulation of nicotinic receptor expression levels, a property which may also have some bearing on their therapeutic effects. We next showed that α4 and α7-nicotinic receptors play important roles in acetylcholinesterase inhibitor-induced neuroprotection and nicotinic receptor up-regulation. Our results also demonstrate the important roles of the phosphatidylinositol 3-kinase pathway downstream of nicotinic receptors in protecting neurons from death and up-regulating nicotinic receptors. This review summarizes recent findings on the roles of the nicotinic receptor in acetylcholinesterase inhibitor-induced neuroprotection and nicotinic receptor up-regulation.

View full abstract

Here we reviewed our recent work on the chronic effects of nicotine on the Na⁺–Ca²⁺ exchanger (NCX) gene and protein expressions in various organs of rats treated with nicotine in the drinking water for 4—12 weeks. Microarray analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) did not detect significant changes in NCX mRNA expression in cerebral cortex, hippocampus, heart and skeletal muscle. However, NCX1 protein was up-regulated by nicotine in cerebral cortex and hippocampus, but was down-regulated in the heart. NCX2 protein was up-regulated by nicotine in hippocampus. We suggest that although mRNA change was insignificant, NCX protein expression was altered by chronic nicotine administration in brain and heart in rats. We also reviewed our work on modulators of NCX gene expression and function in cardiac myocytes.

View full abstract

Multiple lines of evidence, from molecular and cellular to epidemiological, have implicated nicotinic transmission in the pathology of Alzheimer's disease (AD) and Parkinson's disease (PD). This review article presents evidence for nicotinic acetylcholine receptor (nAChR)-mediated protection and the signal transduction involved in this mechanism. The data is based mainly on our studies using rat-cultured primary neurons. Nicotine-induced protection was blocked by an α7 nAChR antagonist, a phosphatidylinositol 3-kinase (PI3K) inhibitor, and an Src inhibitor. Levels of phosphorylated Akt, an effector of PI3K, Bcl-2 and Bcl-x were increased by nicotine administration. From these experimental data, our hypothesis for the mechanism of nAChR-mediated survival signal transduction is that the α7 nAChR stimulates the Src family, which activates PI3K to phosphorylate Akt, which subsequently transmits the signal to up-regulate Bcl-2 and Bcl-x. Up-regulation of Bcl-2 and Bcl-x could prevent cells from neuronal death induced by β-amyloid (Aβ), glutamate and rotenone. These findings suggest that protective therapy with nAChR stimulation could delay the progress of neurodegenerative diseases such as AD and PD.

View full abstract

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) are useful for non-invasive investigation of brain receptors. With these imaging techniques, changes in brain receptor densities and distributions during chronic drug treatments and disease progressions can be tracked for a long period. Appropriate radiolabeled imaging agents are necessary for PET and SPECT molecular imaging. Nicotinic acetylcholine receptors (nAChRs) play important roles in brain functions. The α4β2 and α7 are the major nAChR subtypes in the brain. To date, several subtype selective radiolabeled ligands for nAChR have been reported. For the α4β2 subtype, some agents are already applied for human studies, but only a few agents are developed for the α7 subtype. Here, we overview our results of [^125/123I]5-iodo-3-(2(S)-azetidinylmethoxy)pyridine and 5-[¹¹C]methyl-3-(2-(S)-azetidinylmethoxy)pyridine ([¹¹C]5MA) for α4β2 subtype imaging, and [¹¹C](R)-2-methylamino-benzoic acid 1-aza-bicyclo[2.2.2]oct-3-yl ester ([¹¹C](R)-MeQAA) for α7 subtype imaging.

View full abstract

Nicotinic acetylcholine receptors in the brain play a crucial role in the vasodilation in the cerebral cortex induced by basal forebrain cholinergic activation. Nicotinic receptors can be up-regulated or down-regulated in various conditions, e.g., up-regulation (increase in number) is found in smokers and in rodents exposed to chronic nicotine, while down-regulation (decrease in number) is found in elderly humans and in aged rats. We found in anesthetized rats that the increase in cortical cerebral blood flow induced by bolus intravenous nicotine injection was due to a vasodilation mediated by nitric oxide following activation of nicotinic receptors, probably of α4β2-like subtype, both in the basal forebrain nuclei (Meynert nucleus) and in the cortex. This vasodilative response was reduced by long-term nicotine treatment and also in aged rats. Our results show that functional changes in nicotinic receptors are not always in the same direction as the changes in number; they highlight the importance of investigating not only the changes in receptor numbers but also those in their functional activity.

View full abstract

Silurus asotus (catfish) egg lectin (SAL) has a strong affinity to Gal α-linked carbohydrate chains of not only glycoproteins but also glycosphingolipids such as globotriaosylceramide (Gb3). SAL uniformly bound to surfaces of Gb3-expressing (Gb3⁺) Burkitt's lymphoma cells, while Gb3 molecules were interspersed on the surfaces of Gb3⁺ cells. After a short period of treating Raji and Daudi cells with SAL, each cell size was 10 and 25% smaller than that of untreated cells, respectively. Treatment of Gb3⁺ cells with SAL caused an increase in binding of annexin V, however, neither caspase activation nor DNA fragmentation was observed after treatment with SAL for 22 h. Since SAL did not induce cell death in Gb3⁺ cells, SAL may function as an inducer of early apoptotic signal. We have revealed that SAL did not bind to D-threo-1-phenyl-2-decanoylamino-3-morphorino-1-propanol (D-PDMP)-treated Raji cells, and no cell shrinkage was observed in Gb3-deficient Raji cells treated with SAL, indicating that Gb3 localized in the glycosphingolipid-enriched microdomain (GEM) was involved in SAL-induced cell shrinkage through activation of voltage-gated potassium channel Kv1.3, and that the glycoprotein ligands on Gb3-deficient Raji cells treated with SAL were not included in this phenomenon. These results suggest that SAL leads the cells to early apoptotic status via binding to Gb3 existing in GEM, and that this binding is a prerequisite condition to induce early stage of apoptosis.

View full abstract

We screened a series of new epoxysuccinyl peptides for the development of a lysosomal cathepsin L-specific inhibitor. Among the compounds tested, (2S,3S)-oxirane-2,3-dicarboxylic acid 2-[((S)-1-benzylcarbamoyl-2-phenyl-ethyl)-amide] 3-{[2-(4-hydroxy-phenyl)-ethyl]-amide} (compound CAA0225) was the most potent inhibitor of cathepsin L. CAA0225 inhibited rat liver cathepsin L with IC₅₀ values of 1.9 nM, but not rat liver cathepsin B (IC₅₀, >1000—5000 nM). To assess the contribution of cathepsin L to lysosomal proteolysis, we evaluated autophagy, which is the process of lysosomal self-degradation of cell constituents. In HeLa and Huh-7 cells cultured under nutrient-deprived conditions CAA0225 significantly inhibited degradation of long-lived proteins; however, the magnitude of inhibition was comparable to that in the presence of CA-074-OMe, which is a cathepsin B-specific inhibitor. Thus the contributions of cathepsin L and cathepsin B to autophagic protein degradation of cytoplasmic proteins are nearly equal. During autophagy, microtubule-associated protein IA/IB light chain 3-II (LC3-II) and γ-aminobutyric acid (A) receptor-associated protein (GABARAP)-II, which are specific markers of autophagosomal membranes that engulf cytoplasmic components, also undergo degradation upon fusion of autophagosomes with lysosomes. CAA0225 effectively inhibited degradation of LC3-II and GABARAP, whereas CA-074-OMe had only a marginal effect on their levels. Therefore we conclude that cathepsin L does not play a general role in the degradation of proteins in the lumen of autophagosomes, but rather is involved specifically in the degradation of autophagosomal membrane markers.

View full abstract

A comprehensive gene-expression analysis during platelet (PLT) production from megakaryocytes may give important information on genes involved in the PLT production process. However, the low abundance of primary megakaryocytes makes the gene expression analysis difficult. Therefore, we employed MEG-01 cells, a human megakaryocytic cell line, and confirmed that the cell line produces PLT-like particles by treatment with phorbol myristate acetate (PMA). After treatment of MEG-01 cells with PMA for 8 or 24 h, comprehensive gene expression analysis was carried out using a microarray and Reverse Transcription-Polymerase Chain Reaction (RT-PCR). From the microarray analysis, 141 genes were up-regulated (>2-fold) and 164 genes were down-regulated (<1/2-fold). However, known PLT-related genes were not included in the up- or down-regulated genes. On the other hand, RT-PCR analysis detected increased expression of β1-tubulin, CD62P, gpIbα and gpIII, which are related to PLT function and megakaryocyte differentiation, following PMA treatment for 24 h. These results indicate that the MEG-01 cell may be an alternative model system to study the process of human PLT production from megakaryocytes. The gene-expression analysis might be a powerful tool for identifying genes related to PLT production, if the experimental conditions are optimized.

View full abstract

Major histocompatibility (MHC) class II expression is ordinarily inducible by interferon-gamma (IFN-γ), but the induction is repressed in retinoblastoma protein (Rb)-defective cells. The repression can be rescued by histone deacetylase (HDAC) inhibitor treatment, but this has never been shown for an HDAC inhibitor that is suitable for clinical trials and eventual patient therapy. Here we demonstrate that the HDAC inhibitor, MS-275, can rescue the IFN-γ inducibility of human leukocyte antigen (HLA)-DR in non-small cell lung cancer cells. This HDAC inhibitor is currently being tested in phase I/II clinical trials for non-small cell lung cancer. We further verified that the MS-275 effect is related to an HDAC tethered to the HLA-DRA promoter by the transcription factor, YY1. HDAC inhibitors that can be used to treat patients may augment the expression of tumor cell MHC class II, and the results suggest an opportunity to determine the immunological consequences of HDAC inhibitor treatment in tumor therapy.

View full abstract

During the course of our investigation on the iron acquisition systems in Vibrio parahaemolyticus, a causative agent of seafood-related gastroenteritis, we found that this species utilizes desferri-ferrichrome for growth as a heterologous siderophore (a siderophore produced by other bacteria and fungi) under iron-limiting conditions. N-Terminal amino acid sequence analysis of the iron-repressible outer membrane proteins followed by searches of the reported genomic sequences of this species identified four relevant genes (called fhuACDB) forming an operon. Deletion analysis of the fhuA and fhuD genes indicated that the most upstream gene fhuA and the three downstream genes fhuCDB encode the ferrichrome receptor and the ATP-binding cassette transport components, respectively. Moreover, it was found that the fhuCDB genes are also required for transport of ferric aerobactin which restores growth of this species under iron-limiting conditions.

View full abstract

A DNA fragment responsible for resistance to antimicrobial agents was cloned from chromosomal DNA of Enterococcus faecium FN-1, a clinically isolated strain. Escherichia coli KAM32, a drug-hypersusceptible mutant, was used as a host for gene cloning. Cells of E. coli KAM32 harboring a recombinant plasmid (pTFM8) carrying the DNA fragment became resistant to fluoroquinolones, macrolides, ethidium bromide, 4′,6-diamidino-2-phenylindole (DAPI) and tetraphenylphosphonium chloride (TPPCl). Three complete open reading frames (ORFs) were found in the DNA insert of pTFM8, and the deduced amino acid sequences of one of the ORFs showed high similarity to Mdt(A) from Lactococcus lactis. Mdt(A) is a multidrug efflux pump belonging to a major facilitator superfamily. We designated the ORF efmA. E. coli KAM32 cells harboring the efmA showed energy-dependent efflux of DAPI and TPP⁺. We also observed norfloxacin/H⁺ antiport due to EfmA. The mRNA expression of efmA was observed in E. faecium FN-1 grown without any exogenously added antimicrobial agents. Thus, we conclude that efmA is constitutively expressed under laboratory growth conditions and would contribute to intrinsic resistance against multiple antimicrobial agents in E. faecium FN-1.

View full abstract

In a previous study, we reported that two kaempferol glycosides isolated from Laurus nobilis L., kaempferol-3-O-α-L-(2″,4″-di-E-p-coumaroyl)-rhamnoside (C2) and kaempferol-3-O-α-L-(2″-E-p-coumaroyl-4″-Z-p-coumaroyl)-rhamnoside (C3), showed strong antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci. Thereafter we found that these compounds greatly reduced the minimum inhibitory concentrations (MICs) of some fluoroquinolones in MRSA. In other words, C2 and C3 greatly potentiated anti-MRSA activity of fluoroquinolones. The effect of C2 and C3 with fluoroquinolones was found to be synergistic. The potentiation activity was observed with hydrophilic fluoroquinolones, such as norfloxacin and ciprofloxacin, but not with hydrophobic quinolones. We also found that norfloxacin reduced MICs of C2 and C3. The effect was synergistic. Possible mechanism of the synergistic effect was discussed.

View full abstract

Milk whey proteins contain major components of α-lactalbumin (αLA) and β-lactoglobulin (βLG), and a minor component of lactoferrin (LF). It has been reported that LF reduces nociception and inflammation in various animal models. However, the efficacy of αLA and βLG has not been clarified. This study aimed to assess the efficacy of αLA and βLG in various animal models such as acetic acid-induced writhing, carrageenan-induced paw inflammation, and adjuvant induced-arthritis. Orally administered αLA showed (i) inhibition of writhing induced by acetic acid in mice; (ii) suppression of nociception and inflammation in rat footpads caused by carrageenan in rat; and (iii) therapeutic effects on the development of adjuvant-induced pain and inflammation in rat. In contrast, βLG had no effects in these animal models. To clarify the anti-nociceptive and anti-inflammatory mechanisms of αLA, we examined the levels of interleukin (IL)-6 and prostaglandin (PG)E₂ in carrageenan-injected paw exudates. The administration of αLA 1 h before carrageenan injection inhibited the increased formation of IL-6 and PGE₂ in paw exudates. Next, we demonstrated in vitro enzyme-inhibition assay; cyclooxygenase (COX), phospholipase A₂, and 5-lipoxygenase. αLA inhibited COX and phospholipase A₂ activities. αLA inhibited COX and phospholipase A₂ activities. Moreover, αLA showed selectivity on COX-2 as compared with COX-1. However, 5-lipoxygenase activity was not affected by αLA. These results suggest that αLA is a safe and useful natural drug for patients that require anti-inflammatory drugs, as αLA is contained in dairy food and is frequently ingested as daily food.

View full abstract

Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with Alzheimer's disease (AD) and other forms of senile dementia. BPSD have a serious impact on the quality of life of dementia patients, as well as on that of their caregivers. However, effective drug therapy for BPSD has not been established. Recently, the traditional Japanese medicine Yokukansan (YKS, Yi-gan san in Chinese) has been reported to improve BPSD, such as aggression, agitation, irritability, and hallucinations, in a randomized, single-blind, placebo-controlled study. However, the psychopharmacologic effects of YKS remain unexplored. In the present study, we investigated the effects of YKS on social isolation-induced aggressive behavior and methamphetamine- or MK-801-induced hyperlocomotion in rodents. Social isolation markedly induced aggressive behavior in male Wistar rats. Quetiapine at a dose of 10 mg/kg (per os (p.o.)) significantly inhibited this social isolation-induced aggressive behavior. YKS (100, 300 mg/kg, p.o.) also significantly inhibited the aggressive behavior. Moreover, risperidone (0.1 mg/kg, p.o.) significantly inhibited methamphetamine- or MK-801-induced hyperlocomotion in mice. YKS (300 mg/kg, p.o.) inhibited methamphetamine-induced hyperlocomotion, while YKS at the same dose had no effect on MK-801-induced hyperlocomotion. These findings suggest that YKS may be useful for the treatment of aggression and agitation, and that the psychopharmacologic effects of YKS might be mediated, in part, by inhibiting the activity of the dopaminergic system.

View full abstract

This study was to investigate the probable inhibitory effect of Gαq-protein carboxyl terminus imitation polypeptide-27 (GCIP-27), the optimized form of GCIP, which is a competition candidate of the activated binding sites on Gαq, on the right ventricular (RV) hypertrophy induced by monocrotaline (MCT) in rats. We have previously shown that GCIP-27, can prevent the hypertrophyc responses in cultured rat cardiomyocytes induced by noradrenaline and angiotensin II. Male Sprague-Dawley rats were given a single dose (50 mg/kg) of MCT subcutaneouly to induce pulmonary hypertension (PH) and RV hypertrophy. GCIP-27 (30, 90 μg/kg) or vehicle was administered (twice daily, intraperitoneally) from day 1 to day 21. GCIP-27 (90 μg/kg) inhibited the elevated pulmonary arteria systolic pressure (PASP) and mean pulmonary arteria pressure induced by MCT, but its dose at 30 μg/kg only reduced the elevated PASP. And no effect could be seen on the pulmonary arteria diastolic pressure at both two doses. On the other hand, the two doses of GCIP-27 improved significantly the weight ratio of RV to left ventricle plus septum, the RV free wall thickness and pulmonary arteria acceleration time (PAAT). In morphometric observation, GCIP-27 (30, 90g/kg) could attenuate cardiomyocytes hypertrophy, interstitium fibrosis, mitochondria swelling and malformation markedly in RVs of MCT-treated rats. Furthermore, GCIP-27 (30, 90 μg/kg) significantly reduced the overexpression of the proliferating cell nuclear antigen (PCNA) induced by MCT in RV cardiocytes. The results suggest that GCIP-27 can effectively attenuate the RV hypertrophy induced by MCT in rats, which may be mediated by both the direct effect on cardiomyocyte and the secondary effect by reducing PH, and may be involved in its influence on the Gq signal pathway.

View full abstract

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease characterized by the selective loss of motor neurons. There is no effective treatment or drug against ALS, and the precise mechanisms leading to the selective loss of motor neurons are still unknown. We investigated the effect of a Chinese prescription, Wen-Pi-Tang, on the ALS model mouse SOD1^G93A. Although the oral administration of Wen-Pi-Tang extract to SOD1^G93A mice had no significant effect on body weight loss and survival time, Wen-Pi-Tang delayed disease onset. Therefore, we evaluated immunohistological changes in the spinal cord of SOD1^G93A mice during the early disease period, and found that Wen-Pi-Tang extract inhibited neuronal loss in the lumbar segment of the spinal cord of mice. Furthermore, increased astrocytes and microglial cells, which increase prior to neuronal loss, in spinal cords were significantly reduced in the Wen-Pi-Tang treated group. Since oxidative markers, heme oxygenase-1 and inducible nitric oxide synthase, in the spinal cord were also reduced as well as the change in microglia, the administration of Wen-Pi-Tang was thought to delay disease onset by inhibiting glial cell activation.

View full abstract

Oxidative stress plays an important role in tissue damage associated with many different chronic degenerative diseases, such as cancer and cardiovascular disorders. In our previous study, a novel dipeptide Pro-Arg derived from protamine hydrolysates was found to possess significant antioxidative activity in vitro. In this study, we compared the antioxidant capabilities of purified and synthesized dipeptide (Pro-Arg) and found both of them had very strong hydroxyl-radical scavenging activity in vitro, even at a very low concentration. The protective effect of the dipeptide against oxidative stress was evaluated using H₂O₂-induced oxidative stress of human diploid fibroblasts MRC-5 cell model. Our results showed the dipeptide attenuated H₂O₂-induced cellular oxidative damage, and normalized S phase arrest of MRC-5 cells exposed to H₂O₂. Our findings demonstrate that Pro-Arg can protect against oxidative stress/damage and H₂O₂-induced human diploid fibroblasts cell death.

View full abstract

The pharmacological and pathophysiological characteristics of rat antigen-induced late airway response (LAR) are not yet fully understood. In this study, the pharmacological properties of rat ovalbumin (OVA)-induced LAR and effects of the clinically used anti-asthmatic drugs salbutamol (β₂-agonist), ketotifen (antihistamine), pranlukast (anti-leukotriene C₄/D₄/E₄), and prednisolone (steroid) were examined. In addition, a comparison was made of cell infiltration in bronchoalveolar lavage fluid (BALF) between immediate airway response (IAR) and LAR, and the edematous features of lung during LAR were also examined. Although infiltration of inflammatory cells into BALF was increased in both IAR and LAR, only the increase in eosinophils at 1, 3, and 6 h during LAR were significantly higher than those during IAR. Although β₂-agonist, antihistamine, and anti-leukotriene C₄/D₄/E₄ exhibited no effects on rat LAR, steroid attenuated LAR and decreased eosinophil number in BALF. LAR and the percentage water content were both increased after antigen inhalation, suggesting that LAR is involved in pulmonary edema in rats. In conclusion, antigen-induced LAR was related to pulmonary edema and eosinophil infiltration rather than contraction of airway smooth muscle. This is the first comprehensive study of the profiles of rat antigen-induced LAR, and these analyses of LAR improve understanding of the diverse mechanisms underlying human asthmatic diseases.

View full abstract

Despite of the importance of plasma NO₂⁻ as an index of endothelial nitric oxide (NO) formation and a substrate for NO production, only a limited kinetic knowledge is available in vivo. To address this issue, we intravenously injected NaNO₂ into anesthetized rabbits and quantified changes in arterial and venous plasma NO₂⁻ levels. Plasma NO₂⁻ levels in arterial blood (956±220 nM) were slightly, but significantly, higher than those in venous blood (889±214 nM) under control conditions. Although similar half-lives of the NO₂⁻ were observed in arterial and venous plasma, significant arteriovenous differences were observed in the volume of distribution of the central compartment (0.158±0.007 l/kg in arterial blood and 0.295±0.015 l/kg in venous blood) and the peripheral compartment (0.259±0.035 l/kg in arterial blood and 0.135±0.034 l/kg in venous blood). When NOR1 (authentic NO) was injected, increases in NO₂⁻ levels were greater in arterial plasma, and decreases in blood pressure significantly correlated with arterial NO₂⁻ levels only (r=0.90, p<0.01). These results indicate that changes in NO₂⁻ are larger and more easily detectable as an index of NO formation in arterial plasma.

View full abstract

High-dose methotrexate (HDMTX) chemotherapy with leucovorin (LV) rescue has been used as a therapeutic strategy in oncology since the 1970s. Adverse reactions following extension of methotrexate (MTX) elimination are a crucial problem in HDMTX chemotherapy. MTX is a substrate for drug transporters, which are multidrug resistance protein 2 (Mrp2), organic anion transporter polypeptide 2 (Oatp2) and other transporters. We previously reported that MTX treatment downregulated the expression level of Mrp2 in rats. Here we examined the effect of MTX treatment on the expression of Oatp2, P-glycoprotein (P-gp) and bile salt export pump (Bsep) in rats. MTX was single-injected intraperitoneally at a dose of 150 mg/kg, and Western blot analysis was performed. The levels of Oatp2, P-gp and Bsep in the liver on day 4 after treatment were downregulated to 36.3±6.9%, 51.5±5.2% and 61.8±5.5% (mean±S.E.M.) of controls, respectively. Expression levels of P-gp in the kidney and ileum were also downregulated to 38.5±1.6% and 16.2±1.6% of controls, respectively. These effects of MTX were partially recovered by LV, which rescues normal cells from MTX toxicity. In conclusion, the result indicates that MTX treatment downregulates expression levels of Oatp2, P-gp and Bsep.

View full abstract

The pharmacokinetics of sulfasalazine, an anti-inflammatory drug is influenced by ATP-binding cassette G2 (ABCG2) (breast cancer resistance protein (BCRP), mitoxantrone resistance protein (MXR)) both in vitro and clinically. Due to its low passive permeability, the intracellular concentration of sulfasalazine is dependent on uptake transporters, rendering the characterization of transporter specific interactions in cell based experimental systems difficult. Applying membrane assays a detailed kinetic analysis of sulfasalazine ABCG2 interaction was conducted and K_m values of 0.70±0.03 μM and 0.66±0.08 μM were obtained at pH 7.0 and pH 5.5, respectively.

View full abstract

To determine whether or not a “bolus injection” of soybean-based fat emulsion (SFE), which contains oleic acid (OA), a potent lung-toxic unsaturated C-18 fatty acid, can induce pulmonary dysfunction, we examined the effect of SFE injection on the partial oxygen pressure of arterial blood (Pao₂) and pulmonary vascular permeability. In addition, we compared the effect of an injection of SFE with that of OA, soybean oil (a source of SFE), emulsified OA and C-18 fatty acids. Bolus injection of SFE (0.3—4.8 ml/kg) had little effect on Pao₂ and pulmonary vascular permeability. Injection of an equivalent amount of OA, on the other hand, significantly decreased Pao₂ and increased pulmonary vascular hyper-permeability. This decrease in Pao₂ was attenuated by emulsification. Unemulsified soybean oil also induced a decrease in Pao₂, although the effect was weaker than that of OA. Other unsaturated C-18 fatty acids (linoleic and linolenic acid) induced a decrease in Pao₂ as potent as OA while stearic acid, a C-18 saturated fatty acid, had little effect. Although we did not observe pulmonary toxicity as a result of “bolus injection” of SFE, the chemical form, for example, emulsification and the degree of saturability of the carbon chain, seems to influence the pulmonary toxicities of lipids and fatty acids. Furthermore, the potent pulmonary toxicity of OA seems to depend not only on pulmonary vascular embolization but also pharmacological and/or inflammation-inducing properties.

View full abstract

This article has been deleted at the request of the authors from this journal. The Editorial Committee of the Pharmaceutical Society of Japan (September 17, 2019)

View full abstract

The 50% ethanolic extract (CH-ext) obtained from the unripe fruit of Citrus hassaku exhibited significant tyrosinase inhibitory activity. The CH-ext showed antioxidant activity, such as superoxide dismutase (SOD)-like activity and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. Activity-guided fractionation of the CH-ext indicated that flavanone glycoside-rich fractions showed potent tyrosinase inhibitory activity. Further examination revealed that the tyrosinase inhibitory activity and antioxidant activity of the CH-ext were attributable to naringin and neohesperidin, respectively. The CH-ext showed inhibition of melanogenesis without any effects on cell proliferation in cultured murine B16 melanoma cells after glucosamine exposure. The topical application of the CH-ext to the dorsal skin of brownish guinea pigs showed in vivo preventive effects against UVB-induced pigmentation.

View full abstract

Angiotensin receptor-1 blockers (ARBs) have been used for the treatment of atherosclerosis. Tight junctions are very important in the regulation of cellular permeability which may have a profound role in atherosclerosis. The relationship between them is unresolved. The expression and distribution of zonula occludens-1 (ZO-1), the permeability of cultured endothelial cells, and the activity of phosphatidylinositol 3-kinase (PI3K) were all detected with various methods after cultured endothelial cells were exposed to valsartan and the special ARB telmisartan or combined with PI3K inhibitor wortmannin or the peroxisome proliferator-activated receptor gamma antagonist GW9662. We found that telmisartan but not valsartan downregulated ZO-1 mRNA and protein levels, disrupted the distribution of ZO-1 in cultured endothelial cells, and increased the permeability of endothelial cells in a dose-dependent manner. When the PI3K inhibitor wortmannin was used, the effect induced by telmisartan was at least partly reversed. The role of the PI3K signaling pathway was further confirmed in the PI3K activity assay. GW9662 significantly blocked telmisartan-induced ZO-1 changes. Our results suggest that telmisartan disrupts the continuous pericellular distribution of ZO-1, downregulates the expression of ZO-1 in endothelial cells, and increases the permeability of endothelial cells at least partly through PI3K and the peroxisome proliferator-activated receptor gamma-dependent pathway.

View full abstract

The present study investigated the anti-diabetic effects of new herbal formula (NHF) consist of Polygonati Rhizoma, Rehmanniae Radix, Salviae miltiorrhizae Radix, Puerariae Radix, Schizandrae Fructus, Glycyrrhizae Radix in neonatal streptozotocin (nSTZ)-induced non-insulin-dependent diabetes mellitus (NIDDM) rats. Changes of food and water intakes, body weight, blood glucose, plasma insulin and immunohistochemical evaluation of insulin on pancreas, and mRNA expression of glucose transporter subtype-4 (GLUT-4) in skeletal muscle and hepatic phosphoenolpyruvate carboxykinase (PEPCK) by administration of NHF (300 mg/kg) were investigated. The nSTZ diabetic rats showed hyperglycemia, increases in food and water intake, loss of body weight gain and decrease of the number of insulin-positive cells and the size of β-cells in pancreas and mRNA of GLUT-4 in soleus muscle and increase of hepatic PEPCK mRNA expression. Administration of NHF significantly decreased the blood glucose level, food and water intake and considerably increased the body weight of nSTZ diabetic rats. Also, NHF treatment significantly increased plasma insulin level and the number and size of insulin-immunoreactive cells in the pancreas of nSTZ diabetic rats. In addition, NHF treatment resulted in increased expression of the GLUT-4 mRNA in soleus muscle and in reduced expression of PEPCK mRNA in liver. These results provide possible mechanisms for the anti-diabetic effects of NHF, via a decrease of blood glucose level, an increase of insulin sensitivity, an increase of GLUT-4 gene expression and an attenuation of hepatic PEPCK gene expression. In conclusion, NHF may be useful for improving hyperglycemia and reducing the risk of diabetic complications.

View full abstract

Fibroin, the protein of silk, and hydrolyzed fibroin have recently been described to enhance insulin sensitivity and glucose metabolism in 3T3-L1 adipocytes. Here, we report that a series of synthetic peptides derived from the fibroin sequence have enhancing effects on glucose transport in normal and insulin-resistant 3T3-L1 cells. We observed that, among several enzymatic hydrolysates of fibroin, the chymotryptic and peptic hydrolysates were significantly more effective than others in augmenting insulin-stimulated glucose uptake in both cells. We synthesized several peptides of repetitive sequences in fibroin. Treatment with synthesized hexapeptides enhanced insulin-stimulated glucose uptake more than tri-, tetra- or pentapeptides. Among those, the effect of Gly-Ala-Gly-Ala-Gly-Tyr (GAGAGY) was most robust, and especially its activity of blocking off the chronic-insulin-induced loss of insulin-stimulated uptake was remarkable. Data reveal that the residues of tyrosine situated at the ends of the peptides play a critical role for exerting their activities. We demonstrate that the insulin-sensitizing effect of GAGAGY is due to enhancement of phosphoinositide 3-kinase (PI 3-K) signaling pathway. The GAGAGY-induced insulin-stimulated glucose uptake was sensitive to inhibition of PI 3-K by wortmannin. Phosphorylation of Akt was also elevated in GAGAGY-treated cells. Furthermore, GAGAGY significantly increased insulin-induced glucose transporter 4 (GLUT4) translocation without affecting the synthesis of GLUT4. Our findings suggest that fibroin-derived peptides such as GAGAGY could be considered as novel insulin-sensitizing agents with an activity of blocking the development of insulin resistance.

View full abstract

We constructed a single-chain variable fragment (scFv) antibody against plumbagin (PL) with improved specific binding to PL. Variable heavy- and light-chain genes were cloned directly from the cDNA of hybridoma cell line 3A3 and assembled using the splice-overlap extension polymerase chain reaction (SOE-PCR) with specific primers including flexible peptide (Gly₄Ser)₃ linker primers. The constructed scFv gene was ligated into the pET28a expression vector and transformed into Escherichia coli BL21 (DE3). The denatured protein expressed as inclusion bodies in E. coli was solubilized, purified, and refolded by a stepwise dialysis. Intriguingly, the refolded scFv against PL displayed higher PL-binding specificity than that of its parental monoclonal antibody, MAb 3A3, which suggests the possibility of improving the function by constructing the scFv antibody. These notable properties of the recombinant antibody against PL made it possible to develop an enzyme-linked immunosorbent assay (ELISA) for reliable determination of PL.

View full abstract

An EtOAc-soluble partition of the MeOH extract of a branch of Tetracera scandens (Dilleniaceae family) was subjected to a glucose-uptake assay, which led to the isolation and identification of five isoflavones of previously known structure namely, genistein (1), its derivatives 3′,5′-diprenylgenistein (2), 6,8-diprenylgenistein (3), derrone (4) and alpinumisoflavone (5). Of these, compounds 2—5 exhibited significant glucose-uptake activity in basal and insulin-stimulated L6 myotubes. The findings from adenosine monophosphate-activated kinase (AMPK) activation and glucose transport protein4 (GLUT4) and GLUT1 over-expression revealed certain characteristics of compounds 2—5. These compounds inhibited protein tyrosine phosphatase 1B (PTP1B) activities with IC₅₀ values ranging from 20.63±0.17 to 37.52±0.31 μM. No muscle cell toxicity was reported with compounds 3—5, while compounds 1 and 2 reduced muscle cell viability with IC₅₀ values of 34.27±0.35 and 18.69±0.19 μM, respectively. It was concluded that T. scandens and its constituents exerted highly desirable activities on type 2 diabetes mellitus treatment since they significantly stimulated the uptake of glucose, AMPK phosphorylation, GLUT4 and GLUT1 mRNA expressions and PTP1B inhibition in L6 myotubes.

View full abstract

Allergy-preventive activity was demonstrated for the MeOH extract (HM) of the petals of Hibiscus mutabilis L. ‘versicolor’ MAKINO in a continuing search for allergy-preventive substances from natural sources, using the in vivo assay method. This assay system uses monitoring of a decrease in the blood flow at the tail vein of mice subjected to hen egg-white lysozyme (HEL) sensitization. By bioassay-directed fractionation, a new flavonol triglycoside, quercetin 3-O-[β-D-xylopyranosyl(1→2)-α-L-rhamnopyranosyl(1→6)]-β-D-galactopyranoside (1: mutabiloside), was isolated, together with four known flavonols identified as quercetin 3-O-[β-D-xylopyranosyl(1→2)]-β-D-galactopyranoside (2) and kaempferol 3-O-[β-D-xylopyranosyl(1→2)]-β-D-galactopyranoside (3), quercetin (4) and hyperoside (5). The structure of the new flavonol 1 was elucidated by spectroscopic methods. Among these flavonol derivatives, compounds 1 and 2 showed significant allergy-preventive effects.

View full abstract

The antiviral activity and biodistribution of a glycosylated fusion interferon directed to hepatic receptors were evaluated to determine whether its pharmaceutical concentration in the liver could be improved. The novel glycosylated fusion interferon, galactosyl-human serum albumin-interferon-α2b (G-HSA-IFN) was obtained from a long-term recombinant fusion protein (HSA-IFN) by covalent coupling with a bifunctional reagent, 2-imino-2-ethyloxymethy1-1-thiogalactose. There are about 24 thiogalactose residues in each G-HSA-IFN molecular on average. The antiviral activities of IFNα2b, HSA-IFN, and G-HSA-IFN were compared in a cytopathic effect inhibition assay with the WISH/VSV system in vitro, and the modification had little effect on its antiviral activity. Both G-HSA-IFN and HSA-IFN were labeled with ¹²⁵I and the radiochemical purity of ¹²⁵I-G-HSA-IFN was greater than 96%. ¹²⁵I-G-HSA-IFN bound to the asialoglycoprotein receptor (ASGP-R) on hepatic cells much more specifically than ¹²⁵I-HSA-IFN, with specific binding rates of 89.53% and 6.66%, respectively (p<0.01). Biodistribution research in mice showed that ¹²⁵I-G-HSA-IFN could concentrate effectively in the liver (>45%/g) and suggested that it also could be a good imaging agent of hepatic receptors.

View full abstract

(S)-(+)-Decursin is a coumarin compound present in herbal extracts that has various biological activities. (S)-(+)-Decursin attenuates pathophysiologic progression in cancer, bacterial infection and neuropathy. Asthma is an inflammatory disease associated with increased infiltration of leukocytes, especially eosinophils, and secretion of mucus into the airways. Although (S)-(+)-decursin, as well as (S)-(+)-decursin analogues, have various pharmacological properties, the effect of these compounds on asthma is not known. In the present study, we synthesized (S)-(+)-3-(3,4-dihydroxy-phenyl)-acrylic acid 2,2-dimethyl-8-oxo-3,4-dihydro-2H,8H-pyrano[3,2-g]chromen-3-yl-ester (compound 6, C6) from (S)-(+)-decursin and examined if C6 had any inhibitory effects on lung inflammation in a mouse model of ovalbumin-induced asthma. C6 significantly inhibited the leukocytosis (p<0.01) and eosinophilia (p<0.05) in bronchoalveolar lavage (BAL) fluid. Examination of lung tissues stained with hematoxylin and eosin and periodic acid Schiff reagents showed that C6 suppressed the increased infiltration of inflammatory cells and elevated mucus hypersecretion. Protein levels of interleukin (IL)-5 (p<0.05) and eotaxin (p<0.01) were significantly reduced in BAL fluid by C6. C6 also significantly reduced total and ovalbumin-specific immunoglobulin E (IgE) levels in BAL fluid (p<0.01) as well as that in serum (p<0.05). C6 may have pharmacological effects for asthma and may be a potent therapeutic agent for the treatment of allergic airway diseases.

View full abstract

In the spermatogenesis, many nucleosides and nucleobases are needed for the salvage nucleotide biosynthesis. One of the roles of Sertoli cells is to provide such nutrients to spermatogenic cells located within the blood–testis barrier (BTB). We have already shown that nucleoside transporters are expressed and are functional in primary-cultured rat Sertoli cells and TM4 cells derived from mouse testis. Here, we examined the uptakes of purine ([³H]guanine) and pyrimidine ([³H]uracil) nucleobases using TM4 cells. Uptakes of both nucleobases were time- and concentration-dependent, and kinetic analysis indicated the involvement of high-affinity transport systems. Uptake of uracil was significantly reduced in the absence of Na⁺, although guanine uptake was mainly mediated by a sodium-independent transport system in TM4 cells. Guanine uptake was inhibited by other purine nucleobases, but not by pyrimidine nucleobases. Only pyrimidine nucleobases reduced uracil uptake. In addition, mycophenolic acid, an inosine monophosphate dehydrogenase inhibitor, up-regulated guanine uptake. These results suggested that there are distinct transport systems for purine and pyrimidine nucleobases in cells of mouse Sertoli cell line TM4.

View full abstract

We have previously reported that the metabolism of S-carvedilol in β-naphthoflavone (β-NF)-treated Caco-2 cells is faster than that of R-carvedilol. The aim of the present study was to identify the enzyme responsible for the stereoselective metabolism of carvedilol in the cells. The expression of cytochrome P450 (CYP) 1A1 and CYP1A2 mRNA, but not CYP2D6, CYP3A4, and CYP2C9 mRNA, was increased in β-NF-treated Caco-2 cells, as compared with non-treated cells. Furafylline, an inhibitor of the CYP1A subfamily, decreased the metabolism of S-carvedilol in Caco-2 cells cultured on plastic dishes. In addition, the glucuronidation of carvedilol was not significant in microsomes of β-NF-treated Caco-2 cells. On the other hand, the oxidation of S-carvedilol in microsomes of β-NF-treated Caco-2 cells was faster than that of R-carvedilol, and furafylline decreased the oxidative activity of S-carvedilol. These findings suggested that the CYP1A subfamily was responsible for the stereoselective metabolism of carvedilol in β-NF-treated Caco-2 cells.

View full abstract

The effect of ethanol on the metabolism of S-warfarin and diclofenac by recombinant cytochrome P450 2C9.1 microsomes (CYP2C9.1) was studied. The 7-hydroxylation metabolism of S-warfarin was inhibited by as low as 0.1 vol% (17 mM) ethanol. Ethanol decreased the V_max/K_m and V_max values of S-warfarin metabolism in a concentration-dependent manner, but the K_m value was unchanged by ethanol. The inhibitory effect of ethanol on the 4′-hydroxylation metabolism of diclofenac was not observed even at 1.0 vol% (170 mM) ethanol. Ethanol at a concentration of 3.0 vol% (510 mM) increased the K_m value of diclofenac metabolism without changes in the V_max, which indicates that diclofenac 4′-hydroxylation by CYP2C9.1 was competitively inhibited by ethanol. S-Warfarin metabolism by CYP2C9.1 was more sensitive to ethanol than diclofenac metabolism. These results suggest that ethanol inhibits the metabolism by CYP2C9.1 in a substrate-dependent manner.

View full abstract

Electrolyzed reduced water (ERW) is widely used for drinking by people in Asia. The purpose of this study was to examine the immunological effect of ERW on the immunity of animals by supplying ERW to C57BL/6 mice infected with Echinostoma hortense metacercariae. In the non-infected groups, interleukin (IL)-4 (p<0.001), IL-5, IL-10, IL-1β, tumor necrosis factor (TNF)-α and immunoglobulin (Ig) A expression of the group fed ERW (ERW group) increased in small intestine compared with the normal control group. In the case of infected groups, the group fed ERW (ERW+E. hortense group) showed the result that IL-4, IL-5, IL-10 and Ig A expression increased, but IL-1β and TNF-α (p<0.001) decreased, and the number of goblet cells (p<0.001) and helix pomatia agglutinin (HPA) positive cells increased compared with the group without feeding ERW. However, adult worm recovery rate was markedly increased (p<0.05). On the other hand, the expression of all the cytokines except IL-10 in spleen was mildly increased but not significant statistically, and there was no significant difference in the numerical changes of white blood cell (WBC). These results indicate that feeding ERW may have influence on the local immune response (Th-1 type cytokines such as IL-1β, TNF-α) in the small intestine but not on the systemic immune response.

View full abstract

Several studies have investigated whether dipeptidyl peptidase IV (DPP IV) activity is correlated to the severity of diabetes; however, it remains unclear. To investigate the roles of DPP IV activity in metabolic abnormalities, impaired glucose tolerance rats were produced using a high-fat (HF) or high-sucrose (HS) diet. HF diet-fed rats obviously exhibited impaired glucose tolerance, with increases in subcutaneous and epididymal fat mass, insulin resistance and dyslipidaemia. In rats fed a HS diet rather than a normal diet, lower body weight and fasting blood glucose were observed temporarily in the early period after HS diet feeding; however, impaired glucose tolerance was evoked to some extent with an increase in epididymal fat mass. Both HF and HS diet-fed rats showed significantly higher plasma DPP IV activity than normal diet-fed rats, in the order of HF diet>HS diet>normal diet. HF and HS diets did not significantly affect DPP IV activity and mRNA expression in the kidney. On the other hand, HF, but not HS, diet caused a significant decrease in DPP IV activity in the liver as compared to the control. Of note, both HF and HS diets caused a significant decrease in DPP IV activity in epididymal fat, even though they did not change DPP IV activity in subcutaneous fat. In conclusion, HF or HS diet-induced impaired glucose tolerance with visceral fat accumulation may be interrelated with increased plasma DPP IV activity and decreased DPP IV activity of visceral but not subcutaneous adipose tissue.

View full abstract

Bonito extract (BE), a hot-water extract of bonito muscle, has traditionally been considered as a folk remedy for fatigue. In this study we investigated the effects of BE on physical fatigue. BE was divided into, high, mid, and low-molecular-weight fractions (LMF), to explore the effectiveness of BE compounds. The swimming times to exhaustion of mice administered 0.86 g/kg BE and those administered 0.86 g/kg LMF were significantly longer than those of the vehicle-treated mice in a forced swimming model, indicating that BE possesses an anti-fatigue effect and that the LMF contributes to this effect. The LMF was also confirmed to aid the recovery of locomotor activity after physical fatigue in a forced walking model. We also examined respiratory gas levels and found that oxygen consumption and lipid oxidation were significantly greater in the group administered LMF than in the vehicle group, indicating that LMF promotes the utilization of fatty acids as an energy source. To elucidate why the mice administered LMF showed an anti-fatigue effect, we evaluated metabolic variables during exercise. The concentrations of nonesterified fatty acids and ketone bodies were higher, whereas serum and muscle lactic acid levels were lower in the mice administered LMF than in those in the vehicle group after the start of swimming. When the results were taken as a group they indicated that the effect of BE administration on improving endurance capacity was mediated, at least partly, by an increased utilization of lipids as a source of energy during exercise.

View full abstract

Beta-caryophyllene (BC) is a chemical found in the essential oil of numerous plants which have shown various biomedical properties. In the present investigation we examined for the first time its genotoxic capacity in vivo by evaluating its potential to induce micronuclei in mouse. In a first assay we administered three doses of the compound once, and in a second assay, we administered three doses of BC in three consecutive days. In each assay, the results were compared with those obtained in a group of mice administered corn oil and in another treated with adryamicin. Our results revealed no genotoxic effect by BC in the two assays. Moreover, no bone marrow cyotoxicity was observed when the proportion of polychromatic erythrocytes was determined with respect to the number of normochromatic erythrocytes. Therefore, our study showed the relevance of extending research on BC regarding its beneficial properties.

View full abstract

PEGylation is an established method for improving the pharmacokinetic properties and pharmacodynamic effects of therapeutic proteins. Amino conjugation by N-hydroxysuccinimide activated polyethylene glycol (PEG-NHS) represents the most common modification of the target proteins. In this study, we compared the reaction velocities of pH-dependent preparations of bovine lactoferrin modified with branched PEG-NHS conducted at pH 7.4 to pH 9.0. PEGylation reaction rates were dependent on pH value, but not on PEG molecular mass. At pH 7.4, reactions advanced gradually and reached steady state by 2 h, whereas at pH 9.0, reactions advanced very quickly and reached steady state within 10 min. Hydrolysis half-life of PEG-NHS exceeded 120 min at pH 7.4, but was below 9 min at pH 9.0. Thus, the pH value is one of the most important factors to obtain the optimal condition for PEGylation by NHS esters.

View full abstract