Kamebakaurin Suppresses Antigen-Induced Mast Cell Activation by Inhibition of FcεRI Signaling Pathway.

INTRODUCTION: Kamebakaurin is an active constituent of both Rabdosia japonica and Rabdosia excisa, which are utilized in Chinese traditional medicine for improving symptoms in patients with allergies. We investigated the molecular mechanisms of the anti-allergic effects of kamebakaurin using BMMCs. METHODS: The degranulation ratio, histamine release, and the interleukin (IL)-4, leukotriene B4 (LTB4), and cysteinyl leukotriene productions on antigen-triggered BMMC were investigated. Additionally, the effects of kamebakaurin on signal transduction proteins were examined by Western blot and binding to the Syk and Lyn kinase domain was calculated. The effects of kamebakaurin on antigen-induced hyperpermeability were investigated using mouse model. RESULTS: At 10 µm, kamebakaurin partially inhibited degranulation, histamine release, and IL-4 production. At 30 µm, kamebakaurin partially reduced LTB4 and cysteinyl leukotriene productions and suppressed degranulation, histamine release, and IL-4 production. Phosphorylation of both Syk Y519/520 and its downstream protein, Gab2, was reduced by kamebakaurin, and complete inhibition was observed with 30 µm kamebakaurin. In contrast, phosphorylation of Erk was only partially inhibited, even in the presence of 30 µm kamebakaurin. Syk Y519/520 is known to be auto-phosphorylated via intramolecular ATP present in its own ATP-binding site, and this auto-phosphorylation triggers degranulation, histamine release, and IL-4 production. Docking simulation study indicated kamebakaurin blocked ATP binding to the ATP-binding site in Syk. Therefore, inhibition of Syk auto-phosphorylation by kamebakaurin binding to the Syk ATP-binding site appeared to cause a reduction of histamine release and IL-4 production. Kamebakaurin inhibited antigen-induced vascular hyperpermeability in a dose-dependent fashion but did not reduce histamine-induced vascular hyperpermeability. CONCLUSION: Kamebakaurin ameliorates allergic symptoms via inhibition of Syk phosphorylation; thus, kamebakaurin could be a lead compound for the new anti-allergic drug.

Difference in the Inhibitory Effect of Thiol Compounds and Demetallation Rates from the Zn(II) Active Site of Metallo-ß-lactamases (IMP-1 and IMP-6) Associated with a Single Amino Acid Substitution.

Gram-negative bacteria producing metallo-ß-lactamases (MBLs) have become a considerable threat to public health. MBLs including the IMP, VIM, and NDM types are Zn(II) enzymes that hydrolyze the ß-lactam ring present in a broad range of antibiotics, such as N-benzylpenicillin, meropenem, and imipenem. Among IMPs, IMP-1 and IMP-6 differ in a single amino acid substitution at position 262, where serine in IMP-1 is replaced by glycine in IMP-6, conferring a change in substrate specificity. To investigate how this mutation influences enzyme function, we examined lactamase inhibition by thiol compounds. Ethyl 3-mercaptopropionate acted as a competitive inhibitor of IMP-1, but a noncompetitive inhibitor of IMP-6. A comparison of the crystal structures previously reported for IMP-1 (PDB code: 5EV6) and IMP-6 (PDB code: 6LVJ) revealed a hydrogen bond between the side chain of Ser262 and Cys221 in IMP-1 but the absence of hydrogen bond in IMP-6, which affects the Zn2 coordination sphere in its active site. We investigated the demetallation rates of IMP-1 and IMP-6 in the presence of chelating agent ethylenediaminetetraacetic acid (EDTA) and found that the demetallation reactions had fast and slow phases with a first-order rate constant (kfast = 1.76 h-1, kslow = 0.108 h-1 for IMP-1, and kfast = 14.0 h-1 and kslow = 1.66 h-1 for IMP-6). The difference in the flexibility of the Zn2 coordination sphere between IMP-1 and IMP-6 may influence the demetallation rate, the catalytic efficiency against ß-lactam antibiotics, and the inhibitory effect of thiol compounds.

A Rapid and Sensitive Determination of Histamine in Mast Cells Using a Didansyl Derivatization Method.

BACKGROUND: Mast cells play a central role in allergic responses such as food allergy, asthma, allergic rhinitis, and allergic conjunctivitis. Symptoms in the early phase of these allergic diseases are primarily caused by histamine. However, due to the high histidine content in the cytosol and low histamine content in secretory granules, separating and quantifying histamine from histidine is often difficult. OBJECTIVES: We studied a method for rapid and sensitive quantitation of mast cell-derived histamine and evaluated its application to allergic disease research. METHODS: Bone marrow-derived mouse mast cells (BMMCs) were employed in this study. IgE-sensitized BMMCs were activated by FcεRI cross-linking. After activation, both the histamine released to the supernatant and histamine remaining in BMMCs were didansylated and then analyzed by high-performance liquid chromatography with fluorescence detection (HPLC-FD). Didansyl histamine was synthesized as a standard material. RESULTS: Synthetic didansyl histamine was detected by HPLC-FD with a peak retention time of 18.5 min. Very high linearity of the standard curve was maintained at concentrations of 10 pg/µL or less when the didansyl histamine method was used. This method enables detection of histamine released from 1 × 105 BMMCs. In addition, the histamine concentration in the supernatant due to spontaneous release was also determined. Finally, the ratio of histamine release was highly correlated with the degranulation ratio. CONCLUSION: These results indicate that the proposed method using didansylated histamine to determine mast cell-derived histamine is highly useful for allergy research applications.

Potential Anti-allergic Effects of Bibenzyl Derivatives from Liverworts, Radula perrottetii.

The liverwort Radula perrottetii contains various bibenzyl derivatives which are known to possess various biological activities, such as anti-inflammatory effects. Mast cells (MC) play crucial roles in allergic and inflammatory diseases; thus, inhibition of MC activation is pivotal for the treatment of allergic and inflammatory disorders. We investigated the effects of perrottetin D (perD), isolated from Radula perrottetii, and perD diacetate (Ac-perD) on antigen-induced activation of MCs. Bone marrow-derived MCs (BMMCs) were generated from C57BL/6 mice. The degranulation ratio, histamine release, and the interleukin (IL)-4 and leukotriene B4 productions on antigen-triggered BMMC were investigated. Additionally, the effects of the bibenzyls on binding of IgE to FcεRI were observed by flow cytometry, and signal transduction proteins was examined by Western blot. Furthermore, binding of the bibenzyls to the Fyn kinase domain was calculated. At 10 µM, perD decreased the degranulation ratio (p < 0.01), whereas 10 µM Ac-perD down-regulated IL-4 production (p < 0.05) in addition to decreasing the degranulation ratio (p < 0.01). Both compounds tended to decrease histamine release at a concentration of 10 µM. Although 10 µM perD reduced only Syk phosphorylation, 10 µM Ac-perD diminished phosphorylation of Syk, Gab2, PLC-γ, and p38. PerD appeared to selectively bind Fyn, whereas Ac-perD appeared to act as a weak but broad-spectrum inhibitor of kinases, including Fyn. In conclusion, perD and Ac-perD suppressed the phosphorylation of signal transduction molecules downstream of the FcεRI and consequently inhibited degranulation, and/or IL-4 production. These may be beneficial potential lead compounds for the development of novel anti-allergic and anti-inflammatory drugs.

Crystal Structures of Metallo-ß-Lactamase (IMP-1) and Its D120E Mutant in Complexes with Citrate and the Inhibitory Effect of the Benzyl Group in Citrate Monobenzyl Ester.

The emergence and rapid spread of carbapenem-resistant pathogens producing metallo-ß-lactamases such as IMP-1 and NDM-1 have been of great concern in the global clinical setting. The X-ray crystal structures of IMP-1 from Serratia marcescens and its single mutant, D120E, in complexes with citrate were determined at resolutions of 2.00 and 1.85 Å, respectively. Two crystal structures indicate that a single mutation at position 120 caused a structural change around Zn1, where the geometry changes from a tetrahedron in the native IMP-1 to a square pyramid in D120E. Based on these two complex structures, the authors synthesized citrate monobenzyl ester 1 to evaluate the structural requirement for the inhibitory activity against IMP-1 and compared the inhibitory activities with nonsubstituted citrate. The introduction of a benzyl group into citrate enhanced the inhibitory activity in comparison to citrate (IC50 > 5 mM).

Suppression of IgE-Independent Degranulation of Murine Connective Tissue-Type Mast Cells by Dexamethasone.

Steroidal anti-inflammatory drugs are widely used for the treatment of chronic cutaneous inflammation, such as atopic dermatitis, although it remains unknown how they modulate cutaneous mast cell functions. We investigated the effects of prolonged treatment with a synthetic glucocorticoid, dexamethasone, on murine connective tissue-type mast cells using in vitro and in vivo models. Our connective tissue-type bone marrow-derived cultured mast cell model was found to be sensitive to mast cell secretagogues, such as compound 48/80 and substance P, and higher expression levels of α subunit of a trimeric G protein, Gi1, and several Mas-related G protein-coupled receptor (Mrgpr) subtypes were observed in comparison with immature cultured mast cells. Secretagogue-induced degranulation and up-regulation of these genes was suppressed when cultured in the presence of dexamethasone. The profiles of granule constituents were drastically altered by dexamethasone. Topical application of dexamethasone down-modulated secretagogue-induced degranulation and the expression levels of several Mrgpr subtypes in cutaneous tissue. These results suggest that mast cell-mediated IgE-independent cutaneous inflammation could be suppressed by steroidal anti-inflammatory drugs through the down-regulation of G αi1 and several Mrgpr subtypes in mast cells.

1O, 20O-diacetyl kamebakaurin protects against acetaminophen-induced hepatotoxicity in mice.

The present study aimed to investigate the protective effects of kamebakaurin (KA) and 1O, 20O-diacetyl kamebakaurin (Ac2KA) on acetaminophen (APAP)-induced hepatotoxicity and compare the hepatoprotective mechanisms of the two chemicals. Seven-week-old male C57BL/6J mice were orally administered KA, Ac2KA, or an ethanol/olive oil emulsion once per day for 7-days. Twenty-four hours after the final administration, the mice were fasted and then intraperitoneally injected with 450 mg/kg APAP or saline. At 16 h after injection, the mice were euthanized and blood samples were collected for plasma analysis. Pretreatment with KA and Ac2KA significantly attenuated APAP-induced hepatic injury. The protective effect of Ac2KA was stronger than that of KA. These two chemicals attenuated oxidative stress, inflammatory cytokine production, c-jun N-terminal kinase activation, and receptor-interacting protein (RIP)-3 activation. Ac2KA also decreased APAP-induced RIP-1 activation and nuclear factor kappa B (NF-κB) p65 translocation. Moreover, Ac2KA repressed mRNA expression of Cyp1a2/2e1 in the liver. Our results showed that KA and Ac2KA exerted protective effects against APAP-induced hepatotoxicity. The responsible mechanisms may be related to the chemicals' antioxidant activity and the inhibition of c-jun N-terminal kinase activation and RIP-3 activation. The effects of Ac2KA included those of KA, as well as RIP-1 inactivation, NF-κB inhibition, and Cyp inhibition.

Suppressive effect of kamebakaurin on acetaminophen-induced hepatotoxicity by inhibiting lipid peroxidation and inflammatory response in mice.

BACKGROUND: Kamebakaurin (KA) is an ent-kaurane diterpenoid known to have anti-inflammatory potential. In the current study, we investigated whether pretreatment with KA could ameliorate acetaminophen (APAP)-induced hepatotoxicity by inhibiting the anti-inflammatory response in mice. METHODS: Seven-week-old C57BL/6J mice were orally administered KA or olive oil emulsion for seven days. Twenty-four hours after the last KA or olive oil administration, the mice were intraperitoneally injected with 400mg/kg APAP or saline under feed deprived condition. The mice from each group were euthanized and bled for plasma analysis 24h after the injection. RESULT: APAP increased plasma levels of hepatic injury markers (i.e., alanine aminotransferase and aspartate aminotransferase), lipid peroxidation, and pro-inflammatory cytokines. Pretreatment with KA reduced the magnitude of APAP-induced increases in plasma levels of hepatic injury markers, lipid peroxidation, and inflammatory response. In addition, KA exhibited antioxidant capacity in a dose-dependent manner, with slight reactive oxygen species scavenging activity. CONCLUSION: Our results indicate that KA has the ability to protect the liver from APAP-induced hepatotoxicity, presumably by both inhibiting the inflammatory response and oxidative stress.

Vitamin D3-induced hypercalcemia increases carbon tetrachloride-induced hepatotoxicity through elevated oxidative stress in mice.

The aim of this study was to determine whether calcium potentiates acute carbon tetrachloride (CCl4) -induced toxicity. Elevated calcium levels were induced in mice by pre-treatment with cholecalciferol (vitamin D3; V.D3), a compound that has previously been shown to induce hypercalcemia in human and animal models. As seen previously, mice injected with CCl4 exhibited increased plasma levels of alanine aminotransferase, aspartate aminotransferase, and creatinine; transient body weight loss; and increased lipid peroxidation along with decreased total antioxidant power, glutathione, ATP, and NADPH. Pre-treatment of these animals with V.D3 caused further elevation of the values of these liver functional markers without altering kidney functional markers; continued weight loss; a lower lethal threshold dose of CCl4; and enhanced effects on lipid peroxidation and total antioxidant power. In contrast, exposure to V.D3 alone had no effect on plasma markers of liver or kidney damage or on total antioxidant power or lipid peroxidation. The potentiating effect of V.D3 was positively correlated with elevation of hepatic calcium levels. Furthermore, direct injection of CaCl2 also enhanced CCl4-induced hepatic injury. Since CaCl2 induced hypercalcemia transiently (within 3 h of injection), our results suggest that calcium enhances the CCl4-induced hepatotoxicity at an early stage via potentiation of oxidative stress.

Chronotoxicity of bromobenzene-induced hepatic injury in mice.

The aim of the present study is to investigate whether or not bromobenzene (BB) toxicity varies with circadian periodicity. Seven-week-old male ICR mice were injected with 900 mg/kg (5.73 mmol/kg) BB intraperitoneally at 4 different time points of a day (zeitgeber time [ZT]: ZT0, ZT6, ZT12, and ZT18). Mortality was then monitored for 7 days after injection. Interestingly, mice were sensitive to BB acute toxicity at ZT6 while tolerant at ZT18. Moreover, in mice that were given a non-lethal dose of BB (540 mg (3.44 mmol)/kg), levels of alanine aminotransferase and aspartate aminotransferase, used as markers of hepatic injury, markedly increased in response to injection at ZT6, but did not increase significantly in response to injection at ZT18. In contrast, the markers of renal injury (creatinine and blood urea nitrogen), showed no significant difference in response to the two injection times. To further investigate this extreme circadian variation, we examined hepatic and renal lipid peroxidation levels, and conducted histopathological studies. Similar to our observation with alanine aminotransferase and creatinine, hepatic lipid peroxidation and histopathological changes were more pronounced than renal changes, and showed circadian variation. Our present investigation demonstrated that BB-induced mortality had clear circadian variation, and suggested that hepatic injury was one of the important factors for determination of this variation.

Calcium-deficient diet attenuates carbon tetrachloride-induced hepatotoxicity in mice through suppression of lipid peroxidation and inflammatory response.

The aim of this study is to investigate whether a Ca-deficient diet has an attenuating effect on carbon tetrachloride (CCl4)-induced hepatotoxicity. Four-week-old male ddY mice were fed a Ca-deficient diet for 4 weeks as a part of the experimental protocol. While hypocalcemia was observed, there was no significant change in body weight. The CCl4-exposed hypocalcemic mice exhibited a significant decrease in alanine aminotransferase and aspartate aminotransferase activities at both 6 h and 24 h even though markers of renal function remained unchanged. Moreover, lipid peroxidation was impaired and total antioxidant power was partially recovered in the liver. Studies conducted in parallel with the biochemical analysis revealed that hepatic histopathological damage was attenuated 24 h post CCl4 injection in hypocalcemic mice fed the Ca-deficient diet. Finally, this diet impaired CCl4-induced inflammatory responses. Although upregulation of Ca concentration is a known indicator of terminal progression to cell death in the liver, these results suggest that Ca is also involved in other phases of CCl4-induced hepatotoxicity, via regulation of oxidative stress and inflammatory responses.

Carbon Tetrachloride-Induced Nephrotoxicity in Mice Is Prevented by Pretreatment with Zinc Sulfate.

Carbon tetrachloride (CCl4) is commonly used as a chemical inducer of experimental liver injury. In addition, many studies showed that CCl4 can induce kidney damage. In the current study, we evaluated the protective effect of zinc (Zn) against CCl4-induced nephrotoxicity. We hypothesized that this protective effect would result from the ability of Zn to serve as an inducer of metallothionein (MT), a known endogenous scavenger of free radicals. We administered Zn (as ZnSO4) 50 mg/kg subcutaneously once daily for 3 successive days prior to a single intraperitoneal administration of CCl4 4 g/kg in male ddY mice. Our results showed that Zn pretreatment significantly decreased creatinine and blood urea nitrogen levels and reduced renal histopathological damage at 6 h post-CCl4 injection, observations consistent with enhanced antioxidative activity in the kidney. Moreover, kidney MT levels in the Zn+CCl4-treated group decreased by greater than 70% compared with levels in the Zn-alone group, implying that MT was consumed by CCl4-induced radicals. These findings suggest that prophylaxis with Zn protects mice from CCl4-induced acute nephrotoxicity, presumably by induction of MT, which in turn scavenges radicals induced by CCl4 exposure.

Bromobenzene-induced lethal toxicity in mouse is prevented by pretreatment with zinc sulfate.

In the current study, we evaluated the protective effect of zinc (Zn) against bromobenzene (BB) -induced lethal toxicity. We used Zn because this element is known to be an inducer of metallothionein (MT), which is in turn known to serve as an endogenous scavenger of free radicals. We administered Zn (as ZnSO4) at 50 mg/kg subcutaneously once-daily for 3 successive days prior to a single intraperitoneal administration of 1.2 g/kg BB in male ddY mice. Our results showed that pretreatment with Zn completely abolished the BB-induced mortality of mice until 48 h. We also found that pretreatment of mice with Zn significantly decreased the functional marker levels and reduced the histological damage both in liver and kidney as assessed at 18 h post-BB. We also showed that pretreatment with Zn enhanced antioxidative activity, resulting in decreased lipid peroxidation in both liver and kidney. Moreover, BB-induced calcium levels were downregulated by pretreatment with Zn. In addition, Zn-induced MT was decreased in Zn + BB-treated animals, implying that MT was consumed by BB-induced radicals. These findings suggest that prophylaxis with Zn protects mice from BB-induced lethal toxicity by decreasing oxidative stress in liver and kidney, presumably by induction of MT, which scavenges radicals induced by BB exposure.

Compound 48/80, a Mast Cell Stimulator, Enhances Synthesis of IgE and IgG Induced by Intranasal Application of Ovalbumin in Mice.

Mast cells are well established effector cells of type I hypersensitivity reactions such as allergic rhinitis. However, recent studies have suggested that activated mast cells enhance local immunoglobulin E (IgE) synthesis in the nasal mucosa of allergic rhinitis patients. Therefore, we hypothesized that non-immunological mast cell activators may have the potential to enhance local IgE synthesis. Here, we examined the effect of compound 48/80 (C48/80), a mast cell activator, on IgE and immunoglobulin G (IgG) synthesis. Female Balb/c mice were intranasally administered a mixture of ovalbumin (OVA) (1-10 µg/nose) and C48/80 (1-100 µg/nose) on days 0, 7, 14 and 21 and on consecutive days from day 28 to day 42. Intranasal administration of C48/80 with OVA increased serum OVA-specific IgE and IgG. Double staining with fluorescent-labeled OVA and fluorescent-labeled IgE- or IgG-specific antibody demonstrated the presence of OVA-specific IgE- or IgG-producing cells in the nasal mucosa of sensitized mice. Moreover, intranasal administration of C48/80 with OVA increased the nasal mucosal interleukin (IL)-4 level and enhanced the OVA-induced symptom of sneezing. These results suggested that simultaneous activation of mast cells with antigen exposure enhances local IgE and IgG synthesis.

Nonpeptide neurotrophic agents useful in the treatment of neurodegenerative diseases such as Alzheimer's disease.

Developed regions, including Japan, have become "aged societies," and the number of adults with senile dementias, such as Alzheimer's disease (AD), Parkinson's disease, and Huntington's disease, has also increased in such regions. Neurotrophins (NTs) may play a role in the treatment of AD because endogenous neurotrophic factors (NFs) prevent neuronal death. However, peptidyl compounds have been unable to cross the blood-brain barrier in clinical studies. Thus, small molecules, which can mimic the functions of NFs, might be promising alternatives for the treatment of neurodegenerative diseases. Natural products, such as or nutraceuticals or those used in traditional medicine, can potentially be used to develop new therapeutic agents against neurodegenerative diseases. In this review, we introduced the neurotrophic activities of polyphenols honokiol and magnolol, which are the main constituents of Magnolia obovata Thunb, and methanol extracts from Zingiber purpureum (BANGLE), which may have potential therapeutic applications in various neurodegenerative disorders.

CD72 negatively regulates mouse mast cell functions and down-regulates the expression of KIT and FcεRIα.

CD72 is a transmembrane protein belonging to the C-type lectin family that is expressed by various hematopoietic cells. When bound to its natural ligand, CD100 (semaphorin 4D), CD72 inhibits the KIT-mediated responses of human mast cells, but not IgE/FcεRI-mediated mast cell degranulation. We extended these findings to examine the role of CD72 in mouse mast cells. CD72 expression was detected in mouse bone marrow-derived mast cells (mBMMCs). As for human mast cells, an agonistic antibody against CD72 (K10.6) suppressed the KIT-mediated cell growth of, IL-6 production by and chemotaxis of mBMMCs. However, in contrast to human mast cells, the IgE-triggered degranulation of mBMMCs was suppressed by K10.6. K10.6 did not affect the phosphorylation of SHP-1 in mBMMCs, although SHP-1 mediated the inhibitory effects of CD72 in human mast cells. Administration of K10.6 induced phosphorylation of the ubiquitin ligase Cbl-b and decreased the expression of KIT and FcεRIα on the surface of murine mast cells. We also observed expression of CD72 in a mouse neoplastic cell line, P815, harboring gain-of-function mutations in KIT genes. In addition, we found that K10.6 activated Cbl-b, down-regulated KIT expression and suppressed the mutated KIT-driven growth of these cells. Thus, the mechanism by which CD72 mediates inhibitory effects in mast cells is species-dependent.

Does ß-hexosaminidase function only as a degranulation indicator in mast cells? The primary role of ß-hexosaminidase in mast cell granules.

ß-Hexosaminidase, which is generally present in the lysosome, is essential for glycoprotein metabolism in the maintenance of cell homeostasis. In mast cells (MCs), large amounts of ß-hexosaminidase are present in the granules as opposed to the lysosome, and the biological role of MC ß-hexosaminidase has yet to be fully elucidated. Therefore, we investigated the biological role of ß-hexosaminidase in MC granules. Bone marrow-derived MCs from C57BL/6 (BL/6-BMMC) or ß-hexosaminidase gene-deficient (hexb(-/-)-BMMC) mice were transplanted into MC-deficient (WBB6F1/J-Kit(W)/Kit(W-v) [W/W(v)]) mice to generate MC-reconstituted models. In asthma model experiments, no differences were observed in the symptoms of BL/6, W/W(v), BL/6-BMMC-reconstituted W/W(v), or hexb(-/-)-BMMC-reconstituted W/W(v) mice. In Staphylococcus epidermidis experimental infection model experiments, the severity of symptoms and frequency of death were markedly higher in W/W(v) and hexb(-/-)-BMMC-reconstituted W/W(v) mice than in BL/6 and BL/6-BMMC-reconstituted W/W(v) mice. The growth of S. epidermidis in an in vitro study was clearly inhibited by addition of BL/6-BMMC lysate, but not by addition of hexb(-/-)-BMMC lysate. Moreover, suppression of bacterial proliferation was completely recovered when bacteria were incubated with hexb(-/-)-BMMC lysate plus ß-hexosaminidase. Transmission electron microscopy indicated that the cell wall of S. epidermidis was heavily degraded following coincubation of bacteria with BL/6-BMMC lysate, but not following coincubation with hexb(-/-)-BMMC lysate. These findings strongly suggest that MC granule ß-hexosaminidase is crucial for defense against bacterial invasion, but is not involved in the allergic response. Our results also suggest that the bactericidal mechanism of ß-hexosaminidase involves degradation of bacterial cell wall peptidoglycan.

Generation of mast cells from mouse fetus: analysis of differentiation and functionality, and transcriptome profiling using next generation sequencer.

While gene knockout technology can reveal the roles of proteins in cellular functions, including in mast cells, fetal death due to gene manipulation frequently interrupts experimental analysis. We generated mast cells from mouse fetal liver (FLMC), and compared the fundamental functions of FLMC with those of bone marrow-derived mouse mast cells (BMMC). Under electron microscopy, numerous small and electron-dense granules were observed in FLMC. In FLMC, the expression levels of a subunit of the FcεRI receptor and degranulation by IgE cross-linking were comparable with BMMC. By flow cytometry we observed surface expression of c-Kit prior to that of FcεRI on FLMC, although on BMMC the expression of c-Kit came after FcεRI. The surface expression levels of Sca-1 and c-Kit, a marker of putative mast cell precursors, were slightly different between bone marrow cells and fetal liver cells, suggesting that differentiation stage or cell type are not necessarily equivalent between both lineages. Moreover, this indicates that phenotypically similar mast cells may not have undergone an identical process of differentiation. By comprehensive analysis using the next generation sequencer, the same frequency of gene expression was observed for 98.6% of all transcripts in both cell types. These results indicate that FLMC could represent a new and useful tool for exploring mast cell differentiation, and may help to elucidate the roles of individual proteins in the function of mast cells where gene manipulation can induce embryonic lethality in the mid to late stages of pregnancy.

Phenylbutenoid dimers isolated from Zingiber purpureum exert neurotrophic effects on cultured neurons and enhance hippocampal neurogenesis in olfactory bulbectomized mice.

Trans-3-(3'4'-dimethoxyphenyl)-4-[(E)-3",4"-dimethoxystyryl]cyclohex-1-ene (Comp.1) and cis-3-(3'4'-dimethoxyphenyl)-4-[(E)-3",4"-dimethoxystyryl]cyclohex-1-ene (Comp.2), phenylbutenoid dimers, have been isolated as neurotrophic molecules from an Indonesian medicinal plant, Zingiber purpureum. The aim of this study was to explore the neurotrophic effects of Comp.1 and Comp.2 in vitro and in vivo. Comp.1 (10-30 µM) or Comp.2 (30 µM) significantly induced neurite sprouting in PC12 cells. Comp.1 (0.03-3 µM) or Comp.2 (0.3-3 µM) significantly increased the neurite length and number of neurites in primary cultured rat cortical neurons. Comp.1 (30 µM) and Comp.2 (3-30 µM) also provided significant protection against cell death caused by deprivation of serum. The in vivo effects of both Comp.1 and Comp.2 were evaluated on hippocampal neurogenesis in olfactory bulbectomized (OBX) mice, an experimental depression and dementia animal model. Comp.1 (50mg/kg p.o.), Comp.2 (50mg/kg p.o.), or fluoxetine (10mg/kg i.p.), an antidepressant, were administrated once a day on days 15-28 after OBX. Neurogenesis was assessed by analysis of cells expressing NeuN, a neuronal marker, and 5-bromo-2'-deoxyuridine (BrdU) uptake. Immunohistochemical analysis showed that the number of BrdU/NeuN double-labeled cells in the dentate gyrus was significantly decreased 30 days after OBX. Chronic treatment with Comp.1, Comp.2 or fluoxetine significantly increased the number of BrdU/NeuN double-labeled cells. These results indicate that Comp.1 and Comp.2 have neurotrophic effects, and have the potential for disease modification in depression and dementia.

Magnolol and honokiol prevent learning and memory impairment and cholinergic deficit in SAMP8 mice.

The therapeutic use of neurotrophic factors to treat neurodegenerative disorders, including Alzheimer's disease, is considered feasible. Magnolol and honokiol, constituents of the Magnolia plant, are small organic compounds with neurotrophic activity. We investigated whether magnolol and honokiol can prevent age-related learning and memory impairment and cholinergic deficits in senescence-accelerated mice (SAM). Magnolol (1, 10 mg/kg) or honokiol (0.1, 1 mg/kg) were orally administered to SAMP8 mice once a day for 14 days in 2-month-old mice. Learning and memory performance were evaluated by passive avoidance tests and location and object novelty recognition tests. SAMP8 mice showed significant impairment of learning and memory at 4 and 6 months of age. This age-related learning and memory impairment was prevented by pretreatment with either magnolol (10 mg/kg) or honokiol (1 mg/kg). Cholinergic neuron densities in the medial septum and vertical limb of the diagonal band of the forebrain were evaluated by an immunohistochemical analysis of choline acetyltransferase (ChAT). SAMP8 mice showed a significant cholinergic deficit at 6 months of age. These age-related cholinergic deficits were prevented by treatment with either magnolol (10 mg/kg) or honokiol (1 mg/kg). Moreover, SAMP8 mice showed decreased activity of Akt, a member of the prosurvival pathway, in the forebrain at 2 months of age. A 14-day treatment with either magnolol (10 mg/kg) or honokiol (1 mg/kg) enhanced phosphorylation of Akt in the forebrain at 2 months of age. These results suggest that magnolol and honokiol prevent age-related learning and memory impairment by preserving cholinergic neurons in the forebrain. These compounds may have potential therapeutic applications to various neurodegenerative disorders.