Stroke is one of the leading causes of death and disability in developed countries. Since protecting neurons alone is not sufficient for stroke therapy, research has shifted to the rescue of multiple cell types in the brain. In particular, attention has focused on the study of how cerebral blood vessels and brain cells communicate with each other. Recent findings suggest that cerebral endothelial cells may secrete trophic factors that nourish neighboring cells. Although data are strongest in terms of supporting endothelial–neuronal interactions, it is likely that similar interactions occur in white matter as well. In this mini-review, we summarize recent advances in the dissection of cell–cell interactions in white matter. We examine two key concepts. First, trophic interactions between vessels and oligodendrocytes (OLGs) and oligodendrocyte precursor cells (OPCs) play critical roles in white matter homeostasis. Second, cell–cell trophic coupling is disturbed under diseased conditions that incur oxidative stress. White matter pathophysiology is very important in stroke. A deeper understanding of the mechanisms of oligovascular signaling in normal and pathologic conditions may lead us to new therapeutic targets for stroke and other neurodegenerative diseases.
Ion channels are commonly expressed in recombinant forms with peptide tags, which facilitates their molecular and electrophysiological studies. However, peptide tags may alter ion channel properties. Here we describe the differential effect of peptide tags on the biochemical properties of transient receptor potential vanilloid 6 (TRPV6) channels. Yellow fluorescent protein (YFP)-tagged wild-type TRPV6 (YFP-TRPV6WT) showed much lower levels of aggregate-like bands in Western blots than those of Myc-TRPV6WT. By contrast, the glycosylation level was higher with Myc-TRPV6WT than that with YFP-TRPV6WT. We additionally demonstrate that peptide tags affect the protein integrity of TRPV6 channels. Myc-TRPV6WT was expressed as an intact channel, whereas the pore mutants Myc-TRPV6D542A and Myc-TRPV6D542K were observed to be partially fragmented. By contrast, all YFP-tagged channels were intact, although the YFP-tagged pore mutants were less glycosylated than YFP-TRPV6WT. However, regardless of the peptide tag used, TRPV6D542A and TRPV6D542K electrophysiologically inhibited TRPV6WT which indicates that all pore mutants are equivalent electrophysiologically, not biochemically. Thus, our findings suggest that peptide tags can produce unintended biochemical changes of ion channels which highlight the necessity of careful biochemical evaluation to clarify the roles of ion channels.
Senescence Marker Protein-30 (SMP30) is an androgen-independent factor that decreases with aging. We recently characterized SMP30 as a gluconolactonase (GNL) involved in the biosynthetic pathway of vitamin C and established that SMP30 knockout mice could not synthesize vitamin C in vivo. Although mice normally synthesize vitamin C, humans are prevented from doing so by mutations that have altered the gluconolactone oxidase gene during evolution. Even the SMP30/GNL present abundantly in the human liver does not synthesize vitamin C in vivo. To clarify the functions of this SMP30/GNL, we transfected the human SMP30/GNL gene into the human liver carcinoma cell line, Hep G2. The resulting Hep G2/SMP30 cells expressed approximately 10.9-fold more SMP30/GNL than Hep G2/pcDNA3 mock-transfected control cells. Examination of SMP30/GNL's impact on the state of oxidative stress in these cells revealed that formation of the reactive oxygen species (ROS) of mitochondrial and post-mitochondrial fractions from Hep G2/SMP30 cells decreased by a significant 24.0% and 18.1%, respectively, compared to those from Hep G2/pcDNA3 cells. Lipid peroxidation levels in Hep G2/SMP30 cells similarly decreased. Moreover, levels of the antioxidants superoxide dismutase (SOD) and glutathione (GSH) in Hep G2/SMP30 cells were a significant 42.6% and 62.4% lower than those in Hep G2/pcDNA3 cells, respectively. Thus, over-expression of SMP30/GNL in Hep G2 cells contributed to a decrease of ROS formation accompanied by decreases of lipid peroxidation, SOD activity and GSH levels.
In this study, the delayed effect and related mechanism after chlorpyrifos (CPF) withdrawal was studied in primary rat hippocampal neurons. The results showed that 10 μM CPF induced no detectable cytotoxicity during 96 h continuous exposure while its withdrawal after 48 h exposure induced evident cytotoxicity, as indexed by decreased methyl thiazolyl tetrazolium (MTT) metabolism, increased loss of neurons immunostained by neuron-specific enolase (NSE) antibody, and the increased terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) positive cell rate in the following 24 h and 48 h incubation in the absence of CPF. Extracellular signal-related kinase (ERK)1/2 activation by phosphorylation was observed and persisted during CPF exposure. However, CPF withdrawal after 48 h exposure led to inhibition of ERK1/2 phosphorylation. Carbacol and nerve growth factor (NGF), which are ERK1/2 activators, protected the neurons after CPF withdrawal, while atropine and PD98059, which are ERK1/2 inhibitors, exacerbated the cytotoxicity, indicating the involvement of inhibition of ERK1/2 phosphorylation in CPF-induced delayed cytotoxicity. In conclusion, CPF withdrawal after exposure induced delayed cytotoxicity in cultured neurons. Inhibition of ERK1/2 phosphorylation was found to be related to the delayed cytotoxicity. This finding may provide a new insight into the toxicological mechanism of organophosphorus pesticides, especially chronic organophosphate-induced neuropsychiatric disorder characterized by delayed occurrence.
We have previously reported that a novel gene, factor for adipocyte differentiation (fad) 24, promotes adipogenesis in vitro. To examine the role of fad24 in adipogenesis in vivo and the development of obesity, transgenic mice overexpressing fad24 were generated using mouse fad24 cDNA under the control of a chicken β-actin promoter and cytomegalovirus enhancer. The comparison of the ability of fibroblasts from fad24 transgenic embryos to differentiate into adipocytes with that of fibroblasts from wild-type embryos revealed that fad24 overexpression promotes adipogenesis in embryonic fibroblasts. The weight and histology of white adipose tissues, and serum adipocytokine levels were compared between fad24 transgenic mice and wild-type mice, and we found that fad24 overexpression increased the number of smaller adipocytes, caused hyperplasia rather than hypertrophy in white adipose tissue and increased the serum adiponectin level in mice fed both normal chow and a high-fat diet. Glucose and insulin tolerance tests indicated that the activity for glucose metabolism is improved in fad24 transgenic mice fed normal chow in comparison with that in wild-type mice. Our findings suggest that fad24 is a positive regulator of adipogenesis in vivo. Moreover, the increase in the number of smaller adipocytes caused by the overexpression of fad24 appears to enhance glucose metabolic activity, perhaps by increasing the serum adiponectin level.
The Toll-like receptor 4 (TLR4)-mediated myeloid differentiation factor 88 (MyD88)-dependent signaling pathway plays an essential role in inflammation resulting from invading microbes. However, whether the signaling pathway is activated in the inflammatory reaction of cerebral ischemia-reperfusion and its mechanism is still unclear. In this experiment mice were randomly divided into sham group, ischemia/reperfusion group and TLR4-blocked group with different time points of reperfusion at 12, 24, 48 and 72 h . Mice cerebral ischemia was induced by occlusion of common carotid arteries (CCA) bilaterally. TLR4 signaling pathway was inhibited using specific anti-TLR4 binding protein to prevent TLR4 from interacting with its receptors. We determined the result of TLR4 antibodies-blocking and mice cerebral ischemia-reperfusion injuries by Western blot, and evaluated neuronal damage in the hippocampus. We also determined expression of TLR4 mRNA and MyD88 mRNA by in situ hybridization (ISH), activation of nuclear factor (NF)-κB by electrophoretic mobility-shift analysis (EMSA), and expression of interrleukin (IL)-1β protein by Western blot. The results demonstrated that TLR4-mediated MyD88-dependent signaling pathway activated by ischemia-reperfusion may be involved in the mechanism of ischemia-reperfusion through upregulation of NF-κB, IL-1β.
Planarians are useful animals for regenerative and neuroscience research at the molecular level. Previously, we have reported the distribution and function of neurotransmitter-synthesizing neurons in the planarian central nervous system. In order to understand the neural projections and connections, it is important to understand the distribution of neurotransmitter receptors. In this study, we isolated a serotonin receptor gene and named it DjSER-7 (Dugesia japonica serotonin receptor type 7). DjSER-7-expressing cells were distributed in the planarian brain. According to electrophysiological analysis using Xenopus oocytes, current response was detected upon exposure to serotonin, but not other neurotransmitters in oocytes that were co-injected with mRNAs of both DjSER-7 and Gα chimera B-2, which can interact with either Gq-, Gs- or Gi-coupled receptor. In contrast, current response was not detected after exposure to neurotransmitters in oocytes injected with only DjSER-7 mRNA. Our results indicated that DjSER-7 responds to serotonin, as indicated by electrophysiological analysis using Xenopus oocytes.
Extracellular matrix glycoprotein tenascin-X (TNX) is the largest member of the tenascin family. In this study, we investigated the adhesive properties of TNX and the signaling pathway to be induced to mouse fibroblast L cells on TNX substrate. Approximately 45% of evaluable cells used in the cell adhesion assay were attached to purified TNX but did not spread and were rounded on TNX. The remaining 55% of cells were detached from the TNX substrate and were floating in the conditioned medium. In rounded cells on TNX, phosphorylation of focal adhesion kinase (FAK) was diminished compared with that in cells on control phosphate buffered saline (PBS). To better understand the pathways that lead to the detachment of cells on the TNX substrate, we examined phosphorylation of p38 mitogen-activated protein (MAP) kinase. Phosphorylation of p38 MAP kinase was observed in the rounded cells on TNX in a dose-dependent manner, and the maximum effect was observed at 30 min on TNX. Inhibition of p38 MAP kinase α expression by RNA interference partially suppressed the TNX-induced cell detachment. These results suggest that the p38 MAP kinase is a major mediator of TNX-induced cell detachment.
Since a wide variety of heterogeneity was found in tissue mast cells, recent studies have focused on the process of differentiation and maturation of mast cells. It has been largely accepted that the ability of histamine synthesis is high in the mucosal type mast cells whereas that is low in the tissue-connective type mast cells, although it remains largely unknown how histamine synthesis is regulated during differentiation. Interleukin (IL)-4 is one of the candidate factors that regulate the process of mast cell differentiation. We investigated the effects of IL-4 on histamine synthesis using a murine IL-3-dependent mucosal-type mast cell line, BNu-2cl3. IL-4 drastically suppressed histamine synthesis at the transcriptional levels. Storage of histamine was significantly decreased upon prolonged treatment with IL-4. Down-regulation in expression of histidine decarboxylase by IL-4 was restored by addition of excessive amount of IL-3. Changes in mRNA expression of mouse mast cell proteases (MMCPs) in the cells treated with IL-4 mimicked the differentiation process from mucosal-type to connective tissue-type mast cells; mRNA expression of MMCP2 was decreased, whereas that of MMCP4 and carboxypeptidase A3 were unchanged. These results suggest that IL-4 should play a critical role in suppression of histamine synthesis in mucosal-type mast cells.
Our objective was to investigate the effects of doxycycline, a matrix metalloproteinase (MMP) inhibitor (MMPi) on β-agonist-induced myocardial fibrosis and MMP expression. Twenly-four Wistar-Kyoto rats were divided into 3 groups: control (CTL; n=8), isoproterenol (ISO; n=8), and isoproterenol with doxycycline (ISO+DOX; n=8). ISO and ISO+DOX rats received L-isoproterenol (2.0 mg/kg/d) for 14 d, whereas the CTL group received vehicle. In addition, ISO+DOX rats received a subcutaneous injection of doxycycline (25 mg/kg/d) for 14 d, whereas CTL and ISO rats were injected with saline. Cardiac fibrosis was evaluated via histopathological analysis. MMP-2 and -9 were analyzed by Western blotting and zymography. Compared to the control, the myocardial cross-sectional area and areas of fibrosis were increased significantly in the ISO group, but were attenuated in the ISO+DOX group. MMP-2 activity also increased significantly in the ISO group, but decreased in the ISO+DOX group. Similarly, immunoblotting showed significant increase in MMP-2 and -9 levels in the ISO group, and decreased levels in the ISO+DOX group. Our results suggest that the enhanced expression of MMPs plays a prominent role in promoting myocardial fibrosis in β-agonist signaling pathway, and that MMP-inhibiting compounds may attenuate myocardial fibrosis.
This study was designed to investigate the protective effects of the active part of Artemisia sacrorum Ledeb. Extract (ASE) against acetaminophen (APAP)-induced hepatotoxicity in mice. As a result, pretreated with ASE prior to the administration of APAP significantly prevented the increases of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and tumor necrosis factor-α (TNF-α) levels in serum, and glutathione (GSH) depletion, malondialdehyde (MDA) accumulation in liver tissue. In addition, ASE prevented APAP-induced apoptosis and necrosis, as indicated by a liver histopathological analysis and DNA laddering. Furthermore, according to the results from Western blot analysis, ASE markedly decreased APAP-induced caspase-3 and -8 protein expressions in mouse livers. All these results suggest that the protective effects of ASE against APAP-induced liver injury may involve mechanisms associated with its inhibitive effects of lipid peroxidation and the down-regulation of TNF-α mediated apoptosis.
High concentration of intracellular reactive oxygen species (ROS) plays a role in damaging biological systems. We isolated clitocybin A from the culture broth of Clitocybe aurantiaca and then clitocybin B and C derivatives were synthesized from clitocybin A. IMR-90 lung fibroblast cells were pre-treated or post-treated with clitocybin A, B and C to the addition of 100 μM H2O2. These compounds inhibited the level of intracellular reactive oxygen species (ROS) and H2O2-induced cell death as judged by hypodiploid cell formation. The inhibitory effect of clitocybins on H2O2-induced cell death was comparable to that with N-acetylcysteine (NAC), a well-known ROS scavenger. The inhibition of H2O2-induced cell death by clitocybins was mediated by the reduction of caspase 3 and 9 activation, cytochrome c release from mitochondria and the degradation of IκB-α and IκB-β, which could be resulted in the prevention of cellular senescence. It suggests that clitocybins are novel compounds scavenging ROS and protect cells from apoptosis and cellular senescence.
Cilnidipine is a 1,4-dihydropyridine-derived voltage-dependent calcium channel (VDCC) blocker and suppresses N-type VDCC currents in addition to L-type VDCC currents. An earlier investigation has suggested that intrathecally injected cilnidipine produces antinociception by blocking N-type VDCCs in mice. The present study using the rat formalin model examined antinociceptive effects of intrathecally and orally administered cilnidipine to elucidate a putative site of antinociception of cilnidipine, assess the efficacy of oral cilnidipine for pain relief, and clarify the mechanism(s) responsible for the antinociceptive effect of oral cilnidipine. Cilnidipine (whether intrathecal or oral) suppressed nociception in phases 1 and 2 of the formalin model. In addition, the potency of oral cilnidipine to suppress formalin-induced nociception in phase 2 was greater than that of oral gabapentin, a clinically available drug for treatment of neuropathic pain. Cilnidipine elicited antinociceptive effects without neurological side-effects including serpentine-like tail movement, whole body shaking, and allodynia. Such side-effects can be induced by higher doses of intrathecal ziconotide, a clinically available N-type VDCC blocker. In contrast, orally administered nifedipine, an L-type VDCC blocker, had no effect on either phase of formalin-induced nociception. These results suggest that cilnidipine acts on the spinal cord to produce antinociception and is efficacious for pain relief after oral administration with better safety profile than that of ziconotide. Furthermore, the failure of orally administered nifedipine to affect formalin-induced nociception raises the possibility that oral cilnidipine produces antinociception through, at least in part, spinal N-type VDCC blockade.
Effects of yokukansan (TJ-54) on memory disturbance and behavioral and psychological symptoms of dementia (BPSD) were investigated in thiamine-deficient (TD) rats which were produced by feeding a TD diet for 37 d. Daily oral administration of TJ-54 (0.5, 1.0 g/kg) ameliorated the memory disturbance, anxiety-like behavior, the increase in aggressive behaviors, the decrease in social behaviors, and several neurological symptoms including opisthotonus observed in TD rats, in a dose-dependent manner. In addition, histopathological examinations showed that TJ-54 inhibited the degeneration of neuronal and astroglial cells in the brain stem, hippocampus and cortex in TD rats. Microdialysis experiments showed that TJ-54 inhibited extracellular glutamate rise in the ventral posterior medial thalamus in TD rats. These results suggest that TJ-54 possesses the preventive or progress inhibitive effect against the development of memory disturbance and BPSD-like behaviors induced by the degeneration of neuronal and astroglial cells resulting from TD. TJ-54 may inhibit glutamate-mediated excitotoxicity as one of mechanisms.
To understand memory-enhancing effect of red ginseng biotransformed by Bifidobacterium longum H-1 (RGB), which more potently improved scopolamine-induced learning deficit than red ginseng in the preliminary experiment, its main constituents, ginsenosides Rb1, Rg3 and Rh2, were isolated and their memory-enhancing effects investigated in scopolamine-treated mice by using passive avoidance and Y-maze tests. Among them, ginsenoside Rh2 most potently reversed memory impairment caused by scopolamine. Ginsenoside Rh2 also significantly shortened the escape latencies prolonged by scopolamine in the Morris water maze test (p<0.001) and increased the swimming time shorten by scopolamine within the platform quadrant (p<0.05). The ginsenoside Rh2 (3 μM) reversed scopolamine (10 μM)-induced suppression of long-term potentiation. It recovered field excitatory post synaptic potential (fEPSP) amplitude potentiation to 152.3±8.7% of the control (p<0.05). Based on these findings, RGB and its main constituent, ginsenoside Rh2, might improve learning deficits. Also the memory-enhancing effects of RGB may be dependent on the content of ginsenoside Rh2.
Kososan, a Kampo (Japanese herbal) medicine, has an antidepressive-like effect in behavioral animal models of depression and has been used clinically for the improvement of depressive mood. However, mechanism(s) underlying the antidepressive-like effect of kososan remain unknown. Previous studies showed that orexin-A (OX-A), a neuropeptide that is involved in feeding and arousal, exhibits an antidepressive-like property via hippocampal cell proliferation. Here, we used immunohistochemical analysis with bromodeoxyuridine (BrdU), a marker of proliferating cells, to investigate the effect of long-term treatment with kososan on the orexinergic system and on hippocampal cell proliferation. Oral administration of kososan (1.0 g/kg) or milnacipran (60 mg/kg), a serotonin and noradrenaline reuptake inhibitor, for 28 d led to an antidepressive-like effect in the stress-induced depression-like model mice and reversed the stress-induced decrease in the number of OX-A-positive cells in the lateral hypothalamic area. In addition, both kososan and milnacipran alleviated the stress-induced decrease in the number of BrdU-positive cells in the hippocampal dentate gyrus. Moreover, the antidepressive-like effect and the increase in cell proliferation and in the number of neuropeptide Y (NPY, which is closely associated with orexinergic system)-positive cells in the dentate gyrus induced by kososan were blocked by treatment with SB-334867, an orexin receptor 1 antagonist. These results suggest that kososan exerts an antidepressive-like effect via the improvement of the stress-induced decrease in hippocampal cell proliferation and that the mechanism underlying the antidepressive-like effect of kososan, but not of milnacipran, may be associated with the regulation of orexinergic and/or NPYergic transmission.
We evaluated the novel γ-lactam-based analogue, KBH-A145, for its anticancer activities. KBH-A145 markedly inhibited histone deacetylase (HDAC) activity in vitro and in vivo to an extent comparable to suberoyl-anilide hydroxamic acid (SAHA). The proliferation of various types of cancers was significantly suppressed by KBH-A145, among which MDA-MB-231 and MCF, human breast cancer cells and ACHN human renal cancer cells, were most sensitive. This was accompanied by induction of p21WAF1/Cip1 through compromised recruitment of HDAC1, which leads to hyperacetylation of its promoter region and thus arrested both cells in the G2/M phase. Interestingly, this compound induced apoptosis of MDA-MB-231 cells, but not ACHN cells, through cleavage of poly(ADP-ribose) polymerase (PARP). Taken together, these results show that this novel γ-lactam-based HDAC inhibitor potently inhibits the growth of human breast and renal cancer cells. Thus KBH-A145 is a potential therapeutic agent for the treatment of these types of cancer.
TJN-259 is a chemical substance based on the structural features of the botanically derived ingredient acteoside. This study was performed in order to elucidate the antinephritic effects of TJN-259 in experimental immunoglobulin A (IgA) nephropathy. In this study, 28-week-old ddY mice were used as a spontaneous model of IgA nephropathy. With regard to spontaneous IgA nephropathy, we investigated the effects of TJN-259 administered from 28 to 40 weeks. In addition, an accelerated model of IgA nephropathy was experimentally induced in ddY mice by oral administration of bovine serum albumin, followed by reticuloendothelial blocking by colloidal carbon injection and heminephrectomy. At 10 weeks after the 3rd carbon injection, we also examined the effects of TJN-259 on accelerated IgA nephropathy. To investigate the effects of TJN-259 on transforming growth factor (TGF)-β1 production in accelerated IgA nephropathy, kidneys were isolated and measured TGF-β1 by the enzyme-linked immunosorbent assay (ELISA) method. The administration of TJN-259 to mice with spontaneous IgA nephropathy decreased the incidence of mesangial expansion as well as the number of nuclei per glomerular cross-section in comparison with that of non-treated mice. In addition, TJN-259 treatment prevented the increase in the incidence of mesangial expansion, crescent formation, and segmental sclerosis in glomeruli in accelerated IgA nephropathy. TJN-259 also inhibited the increased immunostaining score of collagen type IV and TGF-β1 in glomeruli of accelerated IgA nephropathy. Treatment with TJN-259 inhibited the increases in renal total and mature TGF-β1 protein levels in accelerated type IgA nephropathy. TJN-259 failed to inhibit the increase in serum IgA levels in both models. These results suggest that TJN-259 was an effective treatment against IgA nephropathy in ddY mice, acting via the suppression of TGF-β1 production in glomeruli.
The effect of morroniside on lipid metabolism and the inflammatory response in the liver of type 2 diabetes model mice was investigated in this study. Male C57BLKS/J db/db mice were divided into the three groups: control (vehicle), morroniside 20, or 100 mg/kg body weight-treated mice. The elevated serum triglyceride and alanine aminotransferase levels as well as hepatic glucose and lipids contents in db/db mice were significantly decreased by the 8-week oral administration of morroniside in a dose-dependent manner. The generations of hepatic thiobarbituric acid-reactive substances and reactive oxygen species induced by hyperglycemia and dyslipidemia were also significantly decreased by the administration of morroniside. In addition, the barometer of an antioxidative state, the oxidized to reduced glutathione ratio, in the liver of db/db mice was markedly increased by morroniside treatment. From protein analysis, the elevated expressions of nuclear factor-κBp65, cyclooxygenase-2, inducible nitric oxide synthase, and sterol regulatory element binding proteins (SREBP-1 and SREBP-2) were down-regulated in the liver of db/db mice. On the other hand, the administration of morroniside significantly increased hepatic peroxisome proliferator activated receptor α expression. These results suggest that morroniside would act as a regulator of hepatic inflammatory reactions and lipid metabolism in db/db mice.
Processed aconite root (PA) is a crude drug used in traditional Chinese or Japanese medicine to generate heat in interior body and dispel cold. We evaluated the effects of PA on hypothermia and reduction in the activity of natural killer (NK) cells in mice exposed to chronic cold stress. Male mice were reared at 4 °C, and powdered PA was administered for 10 d as a food additive. Core body temperature of mice significantly decreased by approximately 1 °C after rearing in a cold environment, and PA administration significantly restored the reduction in core body temperature in a dose-dependent manner. After 10 d, splenic NK-cell activity of cold-stressed mice was significantly reduced, and the reduction was dose-dependently recovered by PA administration. An aconitine-type alkaloid fraction prepared from PA was ineffective when administered to cold-stressed mice, and the thermogenic effect on hypothermic mice was present in the fraction containing low-molecular-weight compounds without alkaloids. In cold-stressed mice, the weight of brown adipose tissue (BAT) and uncoupling protein (UCP)-1 level in BAT increased, whereas the weight of white adipose tissue decreased. The increase in UCP-1 level in BAT of cold-stressed mice was further augmented by PA treatment. These results indicate that PA exhibited a thermogenic effect on hypothermia induced by cold stress in mice by additional upregulation of UCP-1 level in BAT, which was already enhanced by hypothermia, and that the active ingredients present in PA are non-alkaloidal low-molecular-weight compounds.
Ethanol extract of the seeds of Licaria puchury-major, a Brazilian herbal medicine, was found to inhibit cell proliferation in human leukemia cell line (Jurkat) by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Bioassay-guided fractionation of the active components led to the isolation of one phenylpropanoid (1) and ten neolignans (2—11). The apoptosis-inducing activity of the compounds showing cytotoxicity in Jurkat cells was assessed by flow cytometric analysis. Among the identified neolignans, compounds 3, 4, 6 and 7 which have similar molecular structures, showed apoptotic activity. To elucidate the mechanism of apoptosis induction by neolignans, intracellular caspase-3, -8 and -9 activity in Jurkat cells was evaluated. Compound 4 markedly elevated the activity of caspase-3 and -9.
The authors previously reported that costunolide, an active compound isolated from the stem bark of Magnolia sieboldii, induced apoptosis via reactive oxygen species (ROS) and Bcl-2-dependent mitochondrial permeability transition in human leukemia cells. In the present study, the authors investigated whether mitogen-activated protein kinases (MAPKs) are involved in the costunolide-induced apoptosis in human promonocytic leukemia U937 cells. Treatment with costunolide resulted in the significant activation of c-Jun N-terminal kinase (JNK), but not of extracellular-signal-related kinase (ERK1/2) or p38. In vitro kinase assays showed that JNK activity was low in untreated cells but increased dramatically after 30 min of costunolide treatment. U937 cells co-treated with costunolide and sorbitol, a JNK activator, exhibited higher levels of cell death. In addition, inhibition of the JNK pathway using a dominant-negative mutation of c-jun and JNK inhibitor SP600125, significantly prevented costunolide-induced apoptosis. Furthermore, pretreatment with the antioxidant NAC (N-acetyl-L-cysteine) blocked the costunolide-stimulated activation of JNK while the overexpression of Bcl-2 failed to reverse JNK activation. Pretreatment with SP600125 recovered the costunolide-suppressed Bcl-2 expression. These results indicate that costunolide-induced JNK activation acts downstream of ROS but upstream of Bcl-2, and suggest that ROS-mediated JNK activation plays a key role in costunolide-induced apoptosis. Moreover, the administration of costunolide (intraperitoneally once a day for 7 d) significantly suppressed tumor growth and increased survival in 3LL Lewis lung carcinoma-bearing model.
This study investigated the possible antinociceptive effect of the crude extract, fractions and pure compounds (three alkaloids) obtained from fruits of Piper tuberculatum JACQ. (Piperaceae) in acetic acid-induced visceral pain in mice. Oral administration of crude extract and fractions (CH2Cl2, EtOAc, methanol and hexane) (3—300 mg kg−1) caused a dose-related and significant inhibition of the acetic acid-induced visceral nociceptive response. The crude extract, dichloromethane (CH2Cl2) and ethyl acetate (EtOAc) fractions were more potent than methanol and hexane fractions. The isolated alkaloids dihydro-piplartine, piplartine and 3,4,5-trimethoxydihydrocinnamic acid (0.0001—30 mg kg−1) exhibited significant and dose-related antinociceptive effects against acetic acid-induced visceral pain. The results show, for the first time, that crude extract, fractions and pure compounds obtained from P. tuberculatum produce marked antinociception against the acetic acid-induced visceral nociceptive response, supporting the ethnomedical use of P. tuberculatum.
Soluble mucus glycoprotein (S-mucin) processed from the small intestines (ileal region) of freshly slaughtered pigs via homogenization, dialysis, centrifugation and lyophilization and their admixtures with type B gelatin were used to prepare cefaclor-loaded microspheres by the emulsification-crosslinking method. The microspheres were evaluated for the in vitro delivery of cefaclor in both simulated intestinal fluid (SIF) without pancreatin (pH 7.4) and simulated gastric fluid (SGF) without pepsin (pH 1.2). Results obtained indicated that the microspheres formulated were highly mucoadhesive and that release of cefaclor in both release media was non-Fickian and was much higher and more rapid in SGF than in SIF and from microspheres based on gelatin alone when compared to those based on gelatin–procine mucin admixtures. The mean area under the plasma level versus time curves (AUC) was shown to be dependent on the formulation with values of 172.3 μg·h/ml for the control, 278.5 μg·h/ml for microspheres based on gelatin only and 353.0 μg·h/ml for microspheres formulated with equal parts of gelatin and mucin indicating that the rectal route may provide a therapeutically viable alternative to the oral route for the delivery of cefaclor. Further indications also emerged of a possibility of site-specific delivery of cefaclor to the small intestine through a careful selection of gelatin type and porcine mucin admixtures prior to formulation of the microspheres. On the whole, the inclusion of S-mucin in the composition of the microspheres had an enhancer effect on the release and rectal bioavailability of cefaclor which may be exploited in the design of a rectal delivery system of the drug.
The antitumor activity of fucoidan from Fucus vesiculosus was investigated in human colon carcinoma cells. The crude fucoidan, a polysaccharide composed predominantly of sulfated fucose, markedly inhibited the growth of HCT-15 cells (human colon carcinoma cells). After HCT-15 cells were treated with fucoidan, several apoptotic events such as DNA fragmentation, chromatin condensation and increase of the population of sub-G1 hypodiploid cells were observed. In the mechanism of fucoidan-induced apoptosis, we examined changes in Bcl-2 and Bax protein expression levels and activation of caspases. Fucoidan decreased Bcl-2 expression, whereas the expression of Bax was increased in a time-dependent manner compared to the control. In addition, the active forms of caspase-9 and caspase-3 were increased, and the cleavage of poly(ADP-ribose) polymerase (PARP), a vital substrate of effector caspase, was observed. Furthermore, the induction of apoptosis was also accompanied by a strong activation of extracellular signal-regulated kinase (ERK) and p38 kinase and an inactivation of phosphatidylinositol 3-kinase (PI3K)/Akt in a time-dependent manner. These findings provide evidence demonstrating that the pro-apoptotic effect of fucoidan is mediated through the activation of ERK, p38 and the blocking of the PI3K/Akt signal pathway in HCT-15 cells. These data support the hypothesis that fucoidan may have potential in colon cancer treatment.
The mechanism underlying the handling of protein and peptide drugs such as insulin in alveolar epithelial cells is still unclear. We therefore examined fluorescein isothiocyanate-labeled (FITC)-insulin uptake in rat primary cultured alveolar type II epithelial cells and in transdifferentiated type I-like cells. FITC-insulin uptake in these cells was much higher than those of FITC-immunoglobulin (IgG), transferrin, and dextran. FITC-insulin uptake was time- and concentration-dependent, and was almost completely inhibited by metabolic inhibitors in both cells, while bafilomycin A1 inhibited the uptake only in type II cells. Inhibitors of clathrin- and caveolae-mediated endocytosis did not affect FITC-insulin uptake in either type of cell. Dynasore, a dynamin GTPase inhibitor, potently inhibited FITC-insulin uptake in type II cells. These results suggest that the characteristics of insulin uptake in type II and type I cells are different, and dynamin-dependent endocytosis that utilizes neither clathrin nor caveolae is involved in type II cells, while a dynamin-independent pathway is mainly involved in type I cells.
Porphyromonas gingivalis, a type of Gram-negative periodontopathogen, causes periodontal disease by activating intracellular signaling pathways that produce excessive inflammatory responses such as matrix metalloproteinases (MMPs). Recently, we reported that panduratin A, a chalcone compound isolated from Kaempferia pandurata ROXB., caused the decreased levels of MMP-9 secretion, protein, and gene expression in human oral epidermoid KB cells exposed to P. gingivalis supernatant. In this study, we clarified if mitogen-activated protein kinase (MAPK) signaling mediated MMP-9 expression by examining the effect of specific MAPK inhibitors, i.e. U0126, SB203580, and SP600125, on P. gingivalis supernatant-stimulated MMP-9 expression in KB cells. We next elucidated the molecular mechanism by which panduratin A attenuated signaling pathways involved in MMP-9 expression by performing gelatin zymography, Western blotting, reverse transcription-polymerase chain reaction, and promoter assays. Exposure of KB cells to P. gingivalis supernatant up-regulated the expression of MMP-9 protein and gene, and activation of activator protein-1 (AP-1) element, MAPK phosphorylation (extracellular signal-related kinase 1/2 (ERK1/2), p38, and c-Jun N-terminal kinase (JNK)), and transcription factors (Elk1, c-Jun, and c-Fos). A JNK inhibitor (SP600125) significantly attenuated MMP-9 gene expression and AP-1 activity in KB cells in response to P. gingivalis supernatant. Similar to SP600125, panduratin A was found to strongly suppress the level of phosphorylated JNK and block AP-1 activity in P. gingivalis supernatant-stimulated KB cells. In summary, JNK and AP-1 are the major signaling for P. gingivalis supernatant-stimulated MMP-9 expression in KB cells, and panduratin A markedly down-regulates MMP-9 expression through inhibition of these signaling.
Chronic fluoxetine administration can increase neurogenesis in the adult hippocampus, but the molecular mechanisms remain unclear. The Notch1 signaling pathway is expressed highly in the hippocampus and could be a target for diverse environmental modulators of adult neurogenesis. This prompted us to investigate whether the effect of fluoxetine on hippocampal neurogenesis involves Notch1 signaling. In this study, the function of Notch1 signaling was investigated by real time polymerase chain reaction (PCR) and Western blot at different time points (14 d or 28 d) after fluoxetine administration. Simultaneously, hippocampal neurogenesis was determined by assessing cell proliferation, survival and differentiation. mRNA and protein expression of Notch1 signaling components (including Jag1, NICD, Hes1 and Hes5) in the hippocampus increased after fluoxetine administration, accompanied by cell proliferation and survival. These results indicate that chronic fluoxetine administration activates Notch1 signaling in the hippocampus, and the up-regulation of the Notch1 pathway brought about by chronic fluoxetine administration might partly contribute to increased neurogenesis in hippocampus. The findings may provide new insights into the regulatory mechanisms of neurogenesis induced by fluoxetine.
An attempt was made to detach bacterial biofilm, formed by Staphylococcus epidermidis, by using hydrogen peroxide (H2O2) and tungsten compounds. When iron(II) (Fe2+) was mixed with undecatungstophosphate ([PW11O39]7−) and then H2O2, the resulting mixture was able to totally remove the biofilm probably because of co-generation of 1O2 and ·OH. A mixture of undecatungstosilicate ([SiW11O39]8−) and Fe2+ (or Cu2+) also gave a good result, but their catalytic activities for producing ·OH (or 1O2) were rather weak. An electron microscopic study showed that almost nothing was visible on the surface of a biofilm-coated glass after treatment with 1mM [PW11O39]7−+1 mM Fe2+ and 500 mM H2O2 (incubated for 1 h at 37 °C).
Dopamine agonists have neuroprotective properties in addition to their original pharmacologic function. We examined the effects of pergolide mesilate (PM) on the levels of metallothionein mRNA expression and lipid peroxidation in the corpus striata of 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinsonian mice. Mice were administered normal saline (vehicle as a control), PM, or MPTP. A consecutive 7-d administration of MPTP via a gastric tube at a dose of 30 mg/kg significantly decreased metallothionein (MT)-I mRNA expression but did not influence MT-III mRNA expression. Lipid peroxidation, measured as the production of malondialdehyde reactive substances, did not increase after MPTP treatment. Although PM administration alone did not effect MT-I expression, an additional consecutive 7-d administration of PM (30 μg/kg) following MPTP treatment recovered the decreased MT-I level and increased MT-III expression. Lipid peroxidation was significantly suppressed. These results suggest that PM exerts an antioxidative property through the induction of MT-I and MT-III mRNAs simultaneously in response to cellular and/or tissue injury.