Accumulating evidence supports the existence of an overlap in genetic susceptibility with schizophrenia. Translation of human genetic mutations into animals is one of the most important strategies to study the pathogenesis of schizophrenia, identify potential drug targets, and test new medicines for antipsychotic treatment. Recent discoveries of susceptibility genes for schizophrenia make the possibility to develop newer genetic mouse models based on the neurodevelopmental hypotheses of schizophrenia. Although it is not possible to mimic all schizophrenic symptoms by these animal models, the genetic mouse models based on the neurodevelopmental hypothesis are widely developed to reproduce several schizophrenia-like behavioral and biochemical changes in humans. In this mini review, we will discuss the neuropathological and behavioral manifestations of representative genetic mouse models for schizophrenia, associated with the hypothesis of abnormal neurodevelopment.
Schizophrenia is a devastating psychiatric disorder that impairs mental and social functioning and affects approximately 1% of the population worldwide. Genetic susceptibility factors for schizophrenia have recently been reported, some of which are known to play a role in neurodevelopment; these include neuregulin-1, dysbindin, and disrupted-in-schizophrenia 1 (DISC1). Moreover, epidemiologic studies suggest that environmental insults, such as prenatal infection and perinatal complication, are involved in the development of schizophrenia. The possible interaction between environment and genetic susceptibility factors, especially during neurodevelopment, is proposed as a promising disease etiology of schizophrenia. Polyriboinosinic–polyribocytidilic acid (polyI : C) is a synthetic analogue of double-stranded RNA that leads to the pronounced but time-limited production of pro-inflammatory cytokines. Maternal immune activation by polyI : C exposure in rodents is known to precipitate a wide spectrum of behavioral, cognitive, and pharmacological abnormalities in adult offspring. Recently, we have reported that neonatal injection of polyI : C in mice results in schizophrenia-like behavioral alterations in adulthood. In this review, we show how gene-environment interactions during neurodevelopment result in phenotypic changes in adulthood by injecting polyI : C into transgenic mice that express a dominant-negative form of human DISC1 (DN-DISC1). Our findings suggest that polyI : C-treated DN-DISC1 mice are a well-validated animal model for schizophrenia that reflects gene-environment interactions.
Oxytocin (OXT) in the hypothalamus is the biological basis of social recognition, trust, and bonding. We showed that CD38, a leukaemia cell marker, plays an important role in the hypothalamus in the process of OXT release in adult mice. Disruption of Cd38 (Cd38−/−) produced impairment of maternal behavior and male social recognition in mice, similar to the behavior observed in Oxt and OXT receptor (Oxtr) gene knockout (Oxt−/− and Oxtr−/−, respectively) mice. Locomotor activity induced by separation from the dam was higher and the number of ultrasonic vocalization (USV) calls was lower in Cd38−/− than Cd38+/+ pups. These phenotypes seemed to be caused by the high plasma OXT levels during development from neonates to 3-week-old juvenile mice. ADP-ribosyl cyclase activity was markedly lower in the knockout mice from birth, suggesting that weaning for mice is a critical time window of differentiating plasma OXT. Contribution by breastfeeding was an important exogenous source for regulating plasma OXT before weaning by the presence of OXT in milk and the dam's mammary glands. The dissimilarity of Cd38−/− infant behaviour to Oxt−/− or Oxtr−/− mice can be explained partly by this exogenous source of OXT. These results suggest that secretion of OXT into the brain in a CD38-dependent manner may play an important role in the development of social behavior, and mice with OXT signalling deficiency, including Cd38−/−, Oxt−/− and Oxtr−/− mice are good animal models for developmental disorders, such as autism.
Attention-deficit hyperactivity disorder (AD/HD) is a clinically heterogenous disorder including hyperactivity, impulsivity, and inattention. Both psychostimulant and non-psychostimulant drugs such as methylphenidate and atomoxetine, respectively, to modulate catecholeamine neurotransmission are used as current pharmacotherapies for AD/HD. Multiple lines of evidence suggest that genetic factors play major roles in the etiology of AD/HD. meta-Analyses and pooled data analyses have suggested associations between AD/HD and polymorphisms in genes encoding monoamine neurotransmission molecules. There has been considerable research on this disorder using genetic, pharmacological, and neuroimaging approaches, and several animal models of AD/HD such as spontaneously hypertensive rat (SHR), dopamine transporter (DAT) knockout mice, coloboma mutant mouse, and Grin1 mutant mouse have been reported. These animal models are valuable tools for investigating molecular, cellular, and behavioral mechanisms as well as the neural development and circuit mechanisms of AD/HD. Here, we review the recent literature on animal models of AD/HD and discuss their advantages and limitations.
Verticinone, an isosteroidal alkaloid separated from Bulbus Fritillaria (Chinese name “Bei-mu”), was evaluated for its analgesic activities in murine models of inflammatory and neuropathic pain. It was shown that oral administarion of verticinone could significantly inhibit acetic acid-induced writhing response in a dose-dependent way, and the writhing inhibition of 3 mg/kg verticinone was 66.2%, which was approximately higher than that of 200 mg/kg aspirin. In the formalin test, a high dose of (3 mg/kg) verticinone could inhibit the nociceptive response of both phases, but the lower dose (1.5 mg/kg) could only inhibit the second phase response, which suggested that verticinone might exert its analgesic effect through both central and peripheral mechanisms. In addition, in formalin and acetic acid tests, the spontaneous locomotive activities of the mice treated with verticinone were transiently greatly decreased when compared with the vehicle group. In the rat model of paclitaxel induced neuropathic pain, in contrast to the declined analgesic effect of morphine after repeated administration with the same dose, a relatively constant analgesic effect of verticinone was observed. These investigations suggested that verticinone could exert a good antinociceptive effect on inflammatory pain and cancer-related neuropathic pain probably through both peripheral and central mechanisms, and it might be partly involved with some sedation effects. Verticinone is expected to become a potentially novel sedative-analgesic agent without producing tolerance and dependence, but further studies are still urgently needed to elucidate the precise mechanisms and activities of it.
Serine palmitoyltransferase (SPT) is involved in the ceramide synthesis pathway. We investigated the effects of ISP-I, a potent inhibitor of SPT, on the stratum corneum (SC) of hairless mouse skin. Application of ISP-I for one week resulted in a significant decrease in the amount of ceramide, which was associated with a decrease in SC hydration. However, there was an increase in the number of SC layers and less transepidermal water loss than control. Transmission Electron Microscopy observation revealed that the number of desmosome-like structures in the layers immediately above the stratum granulosum (SG) was significantly increased in ISP-I-treated skin compared to vehicle-treated skin. The activity of serine protease—an enzyme associated with the process of desquamation—was lower in the SC of ISP-I-treated skin than control. Furthermore, immunoelectronmicroscopy revealed that glucosylceramide and corneodesmosin tended to remain in corneocytes and were not secreted into the intercellular spaces of the SC in the ISP-I-treated skin. These results indicate that the application of ISP-I decreases ceramide and skin hydration, while at the same time increases the number of SC layers. The accumulation of corneocyte layers may originate from an aberrant desquamation process related to the decrease in the serine protease activity as well as an alteration in the transport of desquamation-related proteases by lamellar bodies.
2-Aminoethoxydiphenyl borate (2-APB) has recently been demonstrated to inhibit gap junction (GJ) channels, whereas the underlying mechanisms are still unknown. Using mouse TM4 Sertoli cell which expresses connexin43 (Cx43), we explored the effects of 2-APB and its analogues on dye-coupling through junctional channels formed by Cx43 and on expression of Cx43. Exposure of the cells to 2-APB (1—50 μM) and one of its analogues diphenylboronic anhydride (DPBA) (1—30 μM) for 4 h leads to a significant decrease in dye coupling of GJ in a concentration-dependent manner. The inhibitory effects of 2-APB and DPBA are reversible since decreased GJ coupling resumes after the two compounds are washed out. The disfunction of GJ induced by 2-APB and DPBA is associated with a decrease in total amount of Cx43 protein and number of GJs on the cell membrane. 2-APB and DPBA do not alter Cx43 phosphorylation state and the level of Cx43 mRNA expression. The loss of Cx43 protein is prevented by either lysosomal or proteasomal inhibitor, suggesting that the decrease in Cx43 results from a 2-APB or DPBA-enhanced degradation of Cx43. The present results indicate that 2-APB and DPBA inhibit GJ communication through decreasing Cx43 expression in TM4 cells.
The balance of angiotensin-converting enzyme (ACE) and angiotensin-converting enzyme 2 (ACE2) in high blood pressure variability (BPV) induced cardiovascular hypertrophy remains elusive. The aim of the present work was to investigate expression and activity of ACE and ACE2 in the heart and aorta of sinoaortic denervation (SAD) rats with high BPV and normal BP, and explore the potential role of ACE and ACE2 in high BPV-induced cardiovascular damage. Hemodynamics, cardiovascular hypertrophy, angiotensin II (Ang II) concentrations, ACE and ACE2 activity were determined. Cardiac-tissue ACE and ACE2 expression were assayed by real-time polymerase chain reaction and Western blot. Compared with sham-operated rats, systolic BPV and diastolic BPV increased and baroreflex sensitivity decreased significantly in SAD rats. SAD rats presented with obvious cardiovascular hypertrophy characterized by increased ratio of left ventricle weight to body weight and aortic weight to the length of aorta. There was no difference in plasma Ang II concentration between sham-operated and SAD rats. The cardiac and aortic ACE expression, aortic ACE2 expression and ACE activity were elevated in SAD rats. There was no significant difference in cardiac ACE2 expressions between sham-operated and SAD rats. The present work demonstrated that cardiac and aortic ACE expression, aortic ACE2 expression and ACE activity were increased in SAD rats. It is the tissue rather than the circulating renin–angiotensin system that contributes to high BPV-induced cardiovascular hypertrophy.
Astragali Radix (AR), prepared from the roots of Astragalus membranaceus (FISCH. ex LINK) BUNGE or its variey, A. membranaceus (FISCH. ex LINK) BUNGE var. mongholicus (BUNGE) HSIAO., is one of the most used and valuable traditional Chinese medicines (TCMs). Historically, Hunyuan, Shanxi Province in China is the geo-authentic producing area of AR and crude AR from here called “geo-authentic.” According to tradition, geo-authentic TCMs define both authenticity and quality. However, no scientific investigation has ever determined whether the superior quality of Hunyuan AR is due to the genetic characteristics or to the local environment. In our study, seeds of 30 AR samples representing the two varieties from different regions were cultivated in Hunyuan under the same conditions. A method, using ultra-performance liquid chromatography coupled with photodiode array detector and evaporative light scattering detectors, was developed to evaluate the quality through a simultaneous determination of four major isoflavonoids and four major saponins. The two AR varieties were successfully distinguished by principal component analysis while samples of the same species with different seeds origins could not be distinguished. A genetic study demonstrated that the internal transcribed spacer sequences of the nuclear ribosomal DNA in A. membranaceus var. mongholicus samples from different geographical regions were highly conservative. These results indicate that the content of active components in AR depends on the interaction of genotype and environment. At the varietal level, genetic properties appear to be more important for pharmaceutical quality than environmental factors, while on the intraspecific level environmental factors might be more important than genetic properties.
It is well known that nutritional status during the fetal and/or lactation period is important for the development of the central nervous system (CNS). In contrast, the effect of malnutrition on postweaning development has not yet been thoroughly investigated. In the present study, we analyzed the behavioral and neuroanatomical effects of protein malnutrition (PM) postweaning in mice. Starting at 20—21 d of age, male ddY mice were maintained on a 5% casein diet (PM group) or 20% casein diet (control group) for 20 d. On the 20th d, body and brain weights of PM mice were lower than those of the control group. PM mice exhibited excessive alertness and spontaneous activity under novel conditions in the Irwin test. In addition, PM mice showed increased open arm exploration in the elevated plus maze compared to control mice. These results suggest that hyperactivity and reduced anxiety behavior or higher impulsiveness in PM mice could be due to an immature brain.
5-Fluorouracil (5-FU)-based chemotherapies with irinotecan have been applied for the treatment of cancers, and a common dose-limiting toxicity is neutropenia and diarrhea. In this study, we investigated the effect of 5-FU treatment on expression levels of drug transporters for SN-38 transportation and SN-38 absorption from the intestine following 5-FU treatment. Expression levels of several drug transporters and nuclear receptors in rats after 5-FU treatment were evaluated. SN-38 absorption from the intestine was evaluated by SN-38 concentration levels in serum following SN-38 injection into the intestine of 5-FU treated rats. The levels of renal multidrug resistance protein 2 (Mrp2) on day 4 after treatment (400 mg/kg) showed significant upregulation, 359.2±33.2% (mean±S.E.) of control. Mrp2 levels in the intestine were downregulated to 26.2±8.4% of control. 5-FU treatment (400 mg/kg) also significantly downregurated expression levels of P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp) to 41.2±14.7%, 15.7±4.3% of control, respectively. To evaluate SN-38 absorption from the intestine, SN-38 was loaded in to the intestine on day 4 after 5-FU treatment. Pretreatment with 5-FU significantly increased SN-38 concentration in the blood 30, 60 and 90 min after SN-38 administration. The area under the curve for SN-38 in the 5-FU group was significantly higher than in vehicle groups. 5-FU treatment decreased expression levels of P-glycoprotein and Bcrp in intestine. The present study suggests that combination chemotherapy of 5-FU with irinotecan (CPT-11) may elevate SN-38 absorption from intestine.
Malformin A1, a cyclopentapeptide of fungal origin, enhances cellular fibrinolytic activity depending on the existence of a cofactor in blood plasma. However, the nature of this cofactor remains unknown. Here, we report that vitronectin acts as a plasma cofactor of malformin A1. We purified the cofactor from bovine plasma by activity-based fractionation, and confirmed that vitronectin in conjunction with plasminogen supports the activity of malformin A1 to promote the fibrinolytic activity of U937 cells. Malformin A1 action was abolished by Arg-Gly-Asp peptide (a competitor of vitronectin–integrin binding), wortmannin (an inhibitor of signaling kinases), and cytochalasin B (an inhibitor of actin polymerization). Changes in actin organization and a decrease in filopodia were observed in cells treated with malformin A1 and plasma. A focal localization of plasminogen on the cell surface was augmented by malformin A1, whereas the amount of cell-surface-bound plasminogen was minimally altered by the treatment. Our results suggest the involvement of cytoskeletal reorganization via vitronectin signaling in the cellular fibrinolytic activity-enhancing action of malformin A1.
Chronic inflammation of rheumatoid arthritis (RA) is promoted by proinflammatory cytokines and closely linked to angiogenesis. In the present study, we investigated the anti-inflammatory effects of emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) isolated from the root of Rheum palmatum L. in interleukin 1 beta (IL-1β) and lipopolysaccharide (LPS)-stimulated RA synoviocytes under hypoxia. Emodin significantly inhibited IL-1β and LPS-stimulated proliferation of RA synoviocytes in a dose-dependent manner under hypoxic condition. Also, enzyme linked immunosorbent assay (ELISA) revealed that emodin significantly reduced the production of pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α), IL-6 and IL-8], mediators [prostagladin E2 (PGE2), matrix metalloproteinase (MMP)-1 and MMP-13] and vascular endothelial growth factor (VEGF) as an angiogenesis biomarker in IL-1β and LPS-treated synoviocytes under hypoxia. Consistently, emodin attenuated the expression of cyclooxygenase 2 (COX-2), VEGF, hypoxia inducible factor 1 alpha (HIF-1α), MMP-1 and MMP-13 at mRNA level in IL-1β and LPS-treated synoviocytes under hypoxia. Furthermore, emodin reduced histone deacetylase (HDAC) activity as well as suppressed the expression of HDAC1, but not HDAC2 in IL-1β and LPS-treated synoviocytes under hypoxia. Overall, these findings suggest that emodin inhibits proinflammatory cytokines and VEGF productions, and HDAC1 activity in hypoxic RA synoviocytes.
Daiokanzoto (DKT), a Kampo medicine that includes the combination of two crude drugs (rhubarb and glycyrrhiza), is clinically effective for constipation. The aim of this study is to clarify the influence of glycyrrhiza, three glycyrrhiza constituents (glycyrrhizin, liquiritin, and liquiritin apioside), and eight antibiotics on the purgative action of DKT, rhubarb, or sennoside A, a constituent of rhubarb, in mice. The purgative actions of rhubarb and sennoside A were significantly intensified when glycyrrhiza was co-administered orally to mice. Liquiritin and liquiritin apioside but not glycyrrhizin showed significant amplification of the purgative action in a dose-dependent manner. The purgative actions of DKT and sennoside A were significantly reduced by the pre-administration of ampicillin, cefcapene pivoxil, faropenem, fosfomycin, or kanamycin, but were not affected by the pre-administration of clarithromycin or levofloxacin. On the other hand, the purgative action of sennoside A was significantly reduced by the pre-administration of minocycline, whereas that of DKT was not affected. The effect of minocycline on the purgative action of sennoside A was lost when glycyrrhiza was co-administered. These results suggest that liquiritin and liquiritin apioside contribute as active substances for the purgative action of DKT, and some antibiotics reduce the purgative action of DKT and sennoside A. Furthermore, glycyrrhiza has the ability to recover the purgative action of sennoside A suppressed by minocycline via an unknown mechanism.
Cadmium (Cd), an industrial and environmental pollutant, preferentially accumulates in the kidney, a major target for Cd-related toxicity. It has been reported that Cd exposure produces reactive oxygen species (ROS) and induces cytotoxicity. Extracellular-superoxide dismutase (EC-SOD) is an antioxidant enzyme that protects the cells from damaging effects of ROS; however, the effect of Cd on the expression of EC-SOD in COS7 cells remains unclear. In this study, exposure to cadmium chloride (CdCl2) enhanced intracellular ROS generation and induced COS7 cell death. Moreover, exposure to Cd decreased the expression of EC-SOD at mRNA and protein levels, but not of other SOD isozymes, copper-and zinc-containing SOD and manganese-containing SOD. The reduction of EC-SOD and cell viability was partially attenuated by pretreatment with an antioxidant, N-acetylcysteine. Further, we determined the involvement of p38-mitogen-activated protein kinase (p38-MAPK) in the reduction of EC-SOD. From these observations, p38-MAPK signaling cascades activated by ROS play a pivotal role in the reduction of EC-SOD, and it is concluded that the reduction of EC-SOD leads to a decrease in the resistance to oxidative stress of Cd-exposed COS7 cells.
Ischemia-reperfusion (I/R) injury of the intestine is an important factor associated with high rates of morbidity and mortality. Intestinal I/R is a common clinical problem in the settings of severe burns, circulatory shock and strangulation ileus. Intestinal I/R damages remote organs and promotes multi-organ failure. It has been shown that enteral feeding before ischemic insults is beneficial for reducing organ injury and improving survival after intestinal I/R. In that study, the authors used a standard complex enteral diet and they suggested that it is important to find new nutrient formulas. Since reactive oxygen species are responsible for intestinal I/R injury, we focused on a dietary polyphenol, the soy isoflavone genistein. Genistein has a wide spectrum of biochemical and pharmacological activities. However, the possibility of a protective effect of genistein as enteral nutrition on I/R injury has not been investigated. We therefore investigated the protective effect of genistein on oxidative injury using intestinal I/R model rats. We found that genistein, which has combined antioxidant activity from radical scavenging, xanthine oxidase inhibition and chain-breaking effects, exhibits a protective effect on intestinal I/R injury. The results suggest that genistein, a soy isoflavone, has the possibility as a new nutrient formula of enteral feeding.
The compound β-citryl-L-glutamate (β-CG) was initially isolated from developing brains, though its functional roles remain unclear. In in vitro experiments, the [Fe(II)(β-CG)] complex activated aconitase in the presence of reducing reagents, whereas no Fe complex with citrate, glutamate, or deferoxamine displayed such an effect. β-CG and [Fe(II)(β-CG)] both bound to the fourth labile Fe atom (Fea) in the [4Fe–4S] cluster of aconitase. Furthermore, [Fe(II)(β-CG)] reactivated aconitase damaged by ammonium peroxodisulfate (APS), while β-CG and citrate had no effect. These findings suggest that [Fe(II)(β-CG)] can transfer Fe to aconitase disassembled by APS. In intact mitochondria, both β-CG and [Fe(II)(β-CG)] bound to Fea of aconitase, whereas only [Fe(II)(β-CG)] reactivated the enzyme disassembled by APS. In cultured neuronal cells, β-CG significantly enhanced cell viability by accelerating mitochondrial activity in primary cultures of neurons from newborn mouse cerebrum tissues. Thus, the β-CG plays a role as an Fe-carrier for mitochondrial aconitase, and then activates it. Taken together, these findings suggest that β-CG is an endogenous low molecular weight Fe chaperone for aconitase.
Tailed duplex (TD) DNAs, prepared by annealing an oligonucleotide to a several-hundred-base single-stranded (ss) DNA fragment, correct a base-substitution mutation with high efficiency. In the present study, the abilities of TD fragments to correct single-base insertion and deletion mutations were examined, using hygromycin-resistance and enhanced green fluorescent protein fusion (Hyg-EGFP) genes inactivated by +G and −C frameshift mutations. The 5′-TD and 3′-TD DNA fragments were co-transfected with plasmid DNA containing the inactivated Hyg-EGFP gene into CHO-K1 cells, and the gene correction efficiencies were determined by introducing the plasmid DNA recovered from the transfected cells into Escherichia coli cells. In contrast to their efficiencies for the substitution mutation, the gene correction abilities of the TD fragments were relatively low. The correction efficiencies by the TD fragments were apparently higher than that by a ss DNA fragment, one of the DNA fragments employed for gene correction. These results suggest that the TD fragments have the potential to correct frameshift mutations, although further improvement is required.
Probiotics are additives containing live microbes that beneficially affect a host by improving the properties of the host intestinal microflora. Recently, advances in medical treatments have led to increased numbers of immunocompromised patients; some patients contract opportunistic infections of Enterococcus species, which are considered non-pathogenic bacteria. To evaluate the safety of probiotics containing Enterococcus strains, we isolated Enterococcus from six probiotic products and compared the pathogenic genes and antimicrobial susceptibility of the probiotic strains to those of clinical isolates. Our study showed that all Enterococcus strains contained in probiotic products were E. faecium, and no vancomycin-resistant strains were found. In addition, no pathogenic genes, such as ace, agg, gelE, cylM, cylB, cylA, cpd, cob, ccf, efaAfs, efaAfm, espfs, or espfm, were found in the probiotic strains. Pulsed-field gel electrophoresis (PFGE) analysis showed obvious genetic differences between the probiotic strains and the clinical isolates. The data suggested that the probiotic Enterococcus strains were not transmitted to hospitalized patients. Therefore, our results strongly suggest that probiotic products are unlikely agents for causing opportunistic infections.
The human ether-a-go-go-related gene (hERG) encodes the α subunit of the potassium current IKr, which plays a pivotal role in cardiac action potential repolarization. Inherited mutations of this gene cause Long QT syndrome type 2. hERG expression is altered by several types of drugs as well as by temperature. Heat shock protein 70 (Hsp70) and Heat shock cognate protein 70 (Hsc70) have reciprocal effects on hERG proteins. We examined the effects of poisonous mushrooms on hERG protein expression and its channel function. Methods: We evaluated the effects of several types of poisonous mushrooms on the expression and function of wild-type hERG by Western blotting, reverse transcription polymerase chain reaction (PCR), and patch clamping in transfected HEK293 cells and mouse HL-1 cardiomyocytes. Results: Extracts of Gymnopilus junonius (junonius) increased expression of both hERG and Hsp70 in HEK293 cells with concomitant decrease in Hsc70, whereas extracts of Amanita ibotengutake (ibotengutake) decreased hERG proteins with increase in Hsc70. Knockdown of Hsp70 and Hsc70 by small interfering RNA abolished the effects of the two mushrooms on hERG, respectively. Certain fractions of junonius increased expression of hERG proteins. hERG currents were increased by extracts of junonius, resulting in shortening of action potential duration (APD). In contrast, hERG currents were decreased and APD was prolonged by extracts of ibotengutake. Conclusion: junonius enhanced the expression and function of hERG by increasing Hsp70 and decreasing Hsc70. Ibotengutake decreased hERG expression via increase in Hsc70. Constituents of junonius may have the potential for use in treatment of arrhythmia.
Depression is a significant public health problem and some reports indicate an association between depression and endoplasmic reticulum stress. Luteolin is a flavonoid contained in many plants and with a variety of known pharmacological properties such as anti-inflammatory, anti-anxiety, and memory-improving effects, suggesting that luteolin penetrates into the brain. In the present study, we investigated the effects of luteolin on endoplasmic reticulum stress-induced neuronal cell death. Luteolin significantly suppressed tunicamycin-induced cell death at 1 to 10 μM in human neuroblastoma cells. Luteolin increased in the expression of the 78 kDa glucose-regulated protein and 94 kDa glucose-regulated protein and decreased in the cleavage activation of caspase-3. Additionally, to investigate whether chronic luteolin treatment has an antidepression effect, we performed some behavioral tests. Chronic luteolin treatment showed antidepressant-like effects in behavioral tests and, luteolin attenuated the expression of endoplasmic reticulum stress-related proteins in the hippocampus of corticosterone-treated depression model mice. These findings indicate that luteolin has antidepressant-like effects, partly due to the suppression of endoplasmic reticulum stress.
Vasodilation profiles following a short-term infusion of nitric oxide (NO), acetylcholine (ACh), and sodium nitroprusside (SNP) into an isolated perfused mesenteric artery bed were analyzed in rats to examine their vasodilatory efficacy under physiological conditions. These compounds commonly increase the intracellular NO concentration to exert vasodilatory activity. In an experiment with exogenous NO infusion where 100 μl of 1 : 300 diluted NO-saturated solution (approx. 53 pmol of NO) was applied, the infusion caused transient vasodilation in a dose-dependent manner, with the peak vasodilation value being 74.7% of the maximum relaxation value. In experiments with ACh, the peak vasodilation value was 81.5% of the maximum at a dose of 60 pmol. The vasodilation profile of ACh was similar to that of NO infusion, but the ACh-induced vasodilation reduced at a slower rate than that induced by NO infusion. The vasodilatory activity of SNP was less potent than that of ACh, and its peak value was 62.8% of the maximum at a dose of 2000 pmol. However, SNP activity was augmented by removing the vascular endothelia of the mesenteric artery bed, and the peak value reached 67.3% of the maximum at a dose of 60 pmol. Pharmacodynamic analysis indicated that NO and ACh are equivalent regarding their vasodilatory efficacy, while the efficacy of SNP was less than 1% of theirs, as the arterial vascular endothelium impeded intracellular SNP-related NO generation, by which 95% of SNP's vasodilatory efficacy was negated. These findings will be helpful to understand factors influencing the therapeutic efficacy of vasodilators.
Diabetic neuropathy is characterized by axonal degeneration, demyelination, and atrophy in association with failed axonal regeneration, remyelination, and synaptogenesis. Recent reports suggest that reduced levels of nerve growth factor (NGF) may play a significant role in the pathogenesis of diabetic polyneuropathy. In this study, we investigated the regulation of NGF by steroid diosgenin (DG) in a diabetic neuropathy rodent model. We found that DG, the primary spirostane-type steroid in several Dioscorea species, increased NGF levels in the sciatic nerve of diabetic rats. Additionally, DG increased neurite outgrowth in PC12 cells and enhanced nerve conduction velocities in the diabetic neuropathy mouse model. DG-treated diabetic mice showed reduced disarrangement of the myelin sheath and increased area of myelinated axons by electron microscope studies and exhibited improvement in the damaged axons. Our data further suggest that DG increased the nerve conduction velocity through induction of NGF. Thus, our findings indicate that DG, a major sapogenin obtained from Dioscorea nipponica, reverses functional and ultrastructural changes and induces neural regeneration in a diabetic neuropathy model.
The present work aimed to investigate the vasorelaxant effect of isotirumalin, a dihydroflavonol isolated from Derris urucu (Leguminosae). The vasorelaxant effect of isotirumalin was investigated in the rat aorta, in the presence and in the absence of a functional endothelium. The production of nitric oxide (NO) induced by isotirumalin was measured simultaneously with its vasorelaxation using carbon microsensors. In endothelium-intact aortic rings, isotirumalin induced a concentration-dependent vasodilator effect the concentration required to produce 30% of relaxation (pIC30=4.84±0.24) that was abolished in endothelium-denuded aortic rings or in the presence of Nω-nitro-L-arginine-methyl-ester (L-NAME; 300 μM). In addition, isotirumalin (100 μM) induced a simultaneous and significant increase on NO production, which was blunted in the presence of L-NAME. The present results demonstrate that isotirumalin is a vasodilator in the rat aorta and act by a mechanism dependent on the presence of a functional endothelium and on NO production.
Stilbenes are a class of compounds that has been reported to inhibit a variety of pathological processes during inflammatory reactions. In this study, cis-ampelopsin E, a stilbene isolated from the seeds of Paeonia suffruticosa, was shown to dose-dependently reduce the nitric oxide (NO) production from lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The reduction in the nitric oxide release occurred in parallel with the comparable inhibition of inducible nitric oxide synthase (iNOS) enzyme expression, which was achieved by cis-ampelopsin E's suppressive effect on nuclear factor-kappa B (NF-κB) signaling activation. By inhibiting LPS-induced inhibitor kinase (IKKα/β) phosphorylation, cis-ampelopsin E significantly decreased LPS-induced IκBα phosphorylation, prevented IκBα degradation, and subsequently reduced the translocating of transcription factor p65 into the nucleus. As a result, the LPS-induced upregulation of NF-κB transcriptional activity was efficiently inhibited. Moreover, it is revealed that cis-ampelopsin E inhibited LPS-induced cyclooxygenase-2 (Cox-2) expression, cPLA2 activation and prostaglandin E2 (PGE2) production. These results, taken together, suggested that cis-ampelopsin E might exert potential anti-inflammatory effects via blockage of the NF-κB signaling pathway.
Previously, the authors demonstrated that the triterpenoid glycoside niga-ichigoside F1 (NIF1) and its aglycone 23-hydroxytormentic acid (23-HTA) isolated from the unripe fruits of Rubus coreanus (Rosaceae) ameliorate cisplatin-induced toxicity in renal epithelial LLC-PK1 cells. In the present study, the nephroprotective effects of NIF1 and 23-HTA were investigated in Sprague-Dawley rats with acute renal injury induced by a single intraperitoneal (i.p.) injection of cisplatin (7 mg/kg). Pretreatment with 23-HTA (10 mg/kg/d, per os (p.o.)) significantly reduced cisplatin-induced elevations in blood urea nitrogen (BUN) and serum creatinine level, whereas NIF1 (10 mg/kg, p.o.) slightly reduced these levels. In addition, pretreatment with 23-HTA prevented cisplatin-induced hydroxyl radical generation, malondialdehyde (MDA) production, glutathione (GSH) depletion, and cisplatin-induced changes in the activities of oxidant and antioxidant enzymes in rat renal tissues. In addition, histopathological examinations showed that 23-HTA pretreatment reduced cisplatin-induced acute tubular necrosis and histological changes. In contrast, NIF1 was found to have a slight or no influence on cisplatin-induced oxidative enzymes and acute tubular necrosis. Taken together, these results suggest that protective effect of 23-HTA pretreatment on cisplatin-induced renal damage is associated with the attenuation of oxidative stress and the preservation of antioxidant enzymes.
We have developed in vivo gene transfer to mesothelial cells on the peritoneal organs, including the stomach. Simple instillation of naked plasmid DNA onto the gastric serosal surface in mice resulted in effective but transient transgene expression. Here, we developed a simple method to improve not only the transfection efficiency but also the duration of transgene expression. Rubbing the gastric serosal surface using a medical spoon immediately after instillation of naked plasmid DNA onto the gastric serosal surface resulted in 59-fold higher transgene expression 24 h after administration in rats. Without rubbing, transgene expression decreased under the detection limit 7 d after administration. On the other hand, rubbing the gastric serosal surface with a medical spoon after instillation of plasmid DNA prolonged transgene expression for one month. Mechanistic study in mice revealed that improved transfection should not be due to stimulation of cell function such as macropinocytosis by rubbing because rubbing before instillation of plasmid DNA did not improve transfection. Plasmid DNA should enter effectively into cells during rubbing. These findings are valuable to develop an effective method of in vivo gene transfer into peritoneal organs.
Oral formulation of tissue kallikrein consists primarily of porcine pancreatic kallikrein (PPK) and is used to improve peripheral circulation, menopausal symptoms, and impaired chorioretinal circulation. Although gastrointestinal absorption of tissue kallikrein after oral administration has been reported in nonclinical and clinical studies, the increase in the concentration of pharmacologically active kinins, which are produced from kininogens by tissue kallikrein, has not been investigated. In this study, kallikrein formulation was orally administered to dogs and an increase in PPK in plasma was confirmed, along with an increase in the blood kinin level. After oral administration of kallikrein formulation (10 U/kg or 20 U/kg PPK) to dogs, PPK concentration in plasma reached maximum 3 h after administration, and then decreased time-dependently. The maximum concentration was 6.01±1.44 pg/ml in the 10 U/kg group and 10.88±3.59 pg/ml in the 20 U/kg group (mean±S.E.M, n=5). After oral administration of kallikrein formulation (40 U/kg PPK) to dogs, the blood kinin concentration in the PPK-treated group was significantly increased 2 h after administration as compared to the purified water-treated group (before administration: 48.8±2.1 ng/ml vs. 48.1±1.9 ng/ml, 2 h after administration: 55.5±1.6 ng/ml vs. 49.6±1.4 ng/ml; mean±S.E.M, n=4, p<0.05). In conclusion, PPK was considered to be absorbed after oral administration and to exert its pharmacological action via kinins produced by kininogen degradation in dogs.