A fluorescent probe for selective detection of lysosomal β-hexosaminidase in live cells

Determining the activity of lysosomal β-hexosaminidase in cells is of great importance for understanding the roles that these enzymes play in pathophysiological events. Herein, we designed the new fluorescent probe, βGalNAc-Rhod-CM(NEt2), which consisted of a βGalNAc-linked rhodol unit serving as a β-hexosaminidase reactive fluorogenic moiety and a N,N'-diethylaminocoumarin (CM(NEt2)) group acting as a fluorescence marker for determining the degree of cell permeabilization. Treatment of βGalNAc-Rhod-CM(NEt2) with β-hexosaminidase promoted generation of Rhod-CM(NEt2), thereby leading to an increase in the intensity of fluorescence of Rhod. However, this probe did not respond to the functionally related glycosidase, O-GlcNAcase. The detection limit of βGalNAc-Rhod-CM(NEt2) for β-hexosaminidase was determined to be 0.52 nM, indicating that it has high sensitivity for this enzyme. Furthermore, the probe functioned as an excellent fluorogenic substrate for β-hexosaminidase with kcat and Km values of 17 sec-1 and 22 μM, respectively. The results of cell studies using βGalNAc-Rhod-CM(NEt2) showed that levels of β-hexosaminidase activity in cells can be determined by measuring the intensity of fluorescence arising from Rhod and that the intensity of fluorescence of CM(NEt2) can be employed to determine the degree of cell permeabilization of the probe. Utilizing the new probe, we assessed β-hexosaminidase activities in several types of cells and evaluated the effect of glucose concentrations in culture media on the activity of this enzyme.

Comparative analyses of various IgE-mediated and non-IgE-mediated inducers of mast cell degranulation for in vitro study

In vitro investigations of mast cell (MC) degranulation are essential for studying many diseases, particularly allergy and urticaria. Many MC-degranulation inducers are currently available. However, there is no previous systematic comparative analysis of these available inducers in term of their efficacies to induce MC degranulation. Herein, we performed systematic comparisons of efficacies of five well-known and commonly used MC-degranulation inducers. RBL-2H3 cells were sensitized with 50 ng/ml anti-DNP IgE or biotinylated IgE followed by stimulation with 100 ng/ml DNP-BSA or streptavidin, respectively. For non-IgE-mediated inducers, the cells were treated with 5 µg/ml substance P, compound 48/80, or A23187. At 15-, 30-, 45- and 60-min post-induction, several common MC-degranulation markers (including intracellular [Ca2+], β-hexosaminidase release, tryptase expression by immunofluorescence staining, cellular tryptase level by immunoblotting, secretory tryptase level by immunoblotting, CD63 expression by immunofluorescence staining, and CD63 expression by flow cytometry) were evaluated. The data showed that all these markers significantly increased after activation by all inducers. Among them, A23187 provided the greatest degrees of increases in intracellular [Ca2+] and β-hexosaminidase release at all time-points and upregulation of CD63 at one time-point. These data indicate that all these IgE-mediated (anti-DNP IgE/DNP-BSA and biotinylated IgE/streptavidin) and non-IgE-mediated (substance P, compound 48/80, and A23187) inducers effectively induce MC degranulation, while A23187 seems to be the most effective inducer for MC degranulation.

Long-Term Exposure of Cultured Astrocytes to High Glucose Impact on Their LPS-Induced Activation

Diabetes mellitus is associated with various complications, mainly caused by the chronic exposure of the cells to high glucose (HG) concentrations. The effects of long-term HG exposure in vitro accompanied by lipopolysaccharide (LPS) application on astrocytes are relatively unknown. We used cell medium with normal (NG, 5.5 mM) or high glucose (HG, 25 mM) for rat astrocyte cultures and measured the release of NO, IL-6, β-hexosaminidase and cell survival in response to LPS. We first demonstrated that HG long-term incubation of astrocytes increased the release of β-hexosaminidase without decreasing MTT-detected cell survival, suggesting that there is no cell membrane damage or astrocyte death but could be lysosome exocytosis. Different from what was observed for NG, all LPS concentrations tested at HG resulted in an increase in IL-6, and this was detected for both 6 h and 48 h treatments. Interestingly, β-hexosaminidase level increased after 48 h of LPS and only at HG. The NO release from astrocytes also increased with LPS application at HG but was less significant. These data endorsed the original hypothesis that long-term hyperglycemia increases proinflammatory activation of astrocytes, and β-hexosaminidase could be a specific marker of excessive activation of astrocytes associated with exocytosis.

Increasing β-hexosaminidase A activity using genetically modified mesenchymal stem cells

GM2 gangliosidoses are a group of autosomal-recessive lysosomal storage disorders. These diseases result from a deficiency of lysosomal enzyme β-hexosaminidase A (HexA), which is responsible for GM2 ganglioside degradation. HexA deficiency causes the accumulation of GM2-gangliosides mainly in the nervous system cells, leading to severe progressive neurodegeneration and neuroinflammation. To date, there is no treatment for these diseases. Cell-mediated gene therapy is considered a promising treatment for GM2 gangliosidoses. This study aimed to evaluate the ability of genetically modified mesenchymal stem cells (MSCs-HEXA-HEXB) to restore HexA deficiency in Tay-Sachs disease patient cells, as well as to analyze the functionality and biodistribution of MSCs in vivo. The effectiveness of HexA deficiency cross-correction was shown in mutant MSCs upon interaction with MSCs-HEXA-HEXB. The results also showed that the MSCs-HEXA-HEXB express the functionally active HexA enzyme, detectable in vivo, and intravenous injection of the cells does not cause an immune response in animals. These data suggest that genetically modified mesenchymal stem cells have the potentials to treat GM2 gangliosidoses.

A one-pot and eco-friendly synthesis of novel β-substituted-α-halomethyl acrylates and the bioactivity of these compounds in an in vitro model of mast cell degranulation induced by pro-inflammatory stimuli

The goal of the present work was to develop novel β-substituted-α-halomethyl acrylates from a methodology in an aqueous phase and to evaluate their bioactivity as potential inhibitors of mast cell activation. Eleven β-substituted-α-halomethyl acrylates were synthesized through a modified Horner-Wadsworth-Emmons reaction. Compound 48/80 and the calcium ionophore A23187 stimulated the release of β-hexosaminidase from mast cells. The effect induced by compound 48/80 was inhibited by compound 5 (320 µM) and compound 9 (160 and 320 µM) without causing cytotoxic effects. The effect induced by A23187 was inhibited by compound 5 (40, 80, 160, and 320 µM) without affecting cell viability. The inhibitory effects exhibited by compounds 5 and 9 were more potent than those of the reference compound sodium cromoglycate at the same concentrations. The biochemical results were consistent with the morphological findings obtained by light and transmission electron microscopy. This study reports, for the first time, that the new synthetic compounds methyl (Z)- 2-bromo-3-(furan-3-yl)acrylate (compound 5) and methyl (E)- 2-bromo-3-(3-bromophenyl)acrylate (compound 9) strongly inhibit mast cell degranulation, without affecting cell viability. The implications of these results are relevant as a basis for developing new anti-inflammatory and mast cell stabilizing drugs.

A novel method for evaluating pseudoallergy based on β-hexosaminidase and its application for traditional Chinese medicine injections

Pseudoallergy is a typical and common adverse drug reaction to injections, especially in traditional Chinese medicine injections (TCMIs). At present, the evaluation methods for pseudoallergy include cell methods in vitro and animal methods in vivo. The mast cell evaluation method based on the β-hexosaminidase (β-Hex)-catalyzed substrate, 4-nitrophenyl-β-N-acetyl-D-glucosaminide (4-NPG), is an important method for the evaluation of drug-induced pseudoallergy, but it is prone to false positive results and has insufficient sensitivity. In this study, a novel β-Hex evaluation system with rat basophilic leukemia-2H3 cells based on high-performance liquid chromatography-fluorescence detection (HPLC-FLD) was established, which effectively increased the sensitivity and avoided false positive results. Cell viabilities were measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay. In addition, a method for the determination of histamine, which is another indicator in the development of pseudoallergy, was established to validate the above method. The results of this novel method indicated that two TCMIs (Shuxuening injection and Shenqi Fuzheng injection), which were considered to be pseudoallergenic using 4-NPG, were not pseudoallergenic. Overall, the novel β-Hex/HPLC-FLD evaluation system using Rat basophilic leukemia-2H3 cells established was effective and precise. It could be used for the evaluation of pseudoallergic reactions caused by TCMIs and other injections.

Rosa davurica Inhibited Allergic Mediators by Regulating Calcium and Histamine Signaling Pathways

Rosa davurica Pall. exhibits antioxidant, antiviral, and anti-inflammatory properties; however, its pharmacological mechanism in allergy is yet to be understood. This study confirmed the effects of R. davurica Pall. leaf extract (RLE) on allergy as a new promising material. To evaluate the therapeutic potential of RLE against allergy, we investigated the effects of RLE on the regulatory β-hexosaminidase, histamine, histidine decarboxylase (HDC), Ca²⁺ influx, nitric oxide (NO), and cytokines induced by lipopolysaccharide (LPS) and DNP-IgE/BSA in Raw 264.7 and RBL-2H3 cells. Furthermore, we examined the effects of RLE on the signaling pathways of mitogen-activated protein kinase (MAPK) and Ca²⁺ pathways. After stimulating Raw 264.7 cells with LPS, RLE reduced the release of inflammatory mediators, such as NO, cyclooxygenase (COX)-2, inducible nitric oxygen synthase (iNOS), interleukin (IL)-1β, -6, and tumor necrosis factor (TNF)-α. Also, RLE reduced the β-hexosaminidase, histamine, HDC, Ca²⁺ influx, Ca²⁺ pathways, and phosphorylation of MAPK in DNP-IgE/BSA-stimulated RBL-2H3 cells. Our studies indicated that RLE is a valuable ingredient for treating allergic diseases by regulating cytokine release from macrophages and mast cell degranulation. Consequently, these results suggested that RLE may serve as a possible alternative promising material for treating allergies.

Ameliorative Effects of Daphnopsis costaricensis Extract against Oxazolone-Induced Atopic Dermatitis-like Lesions in BALB/c Mice

The genus Daphnopsis has been traditionally used as a purgative, diuretic, stimulant, and psoriasis treatment. In this study, the anti-AD (atopic dermatitis) activities of the Daphnopsis costaricensis EtOH extract (DCE) were investigated in an oxazolone (OX)-induced mouse model of AD, and the anti-inflammatory effects of its active compounds were confirmed in PI-sensitized or IgE/DNP-BSA-sensitized RBL-2H3 cells. DCE improved the symptoms of OX-induced inflammatory dermatitis (swelling, erythema, and increased ear thickening) in OX-induced BALB/c mice ears and reduced epidermal thickness and mast cell infiltration. Eleven flavonoid compounds were isolated from DCE, and two compounds (7,8-dimethoxyflavone and 7,2'-dimethoxyflavone) significantly inhibited IL-4 overexpression in PI-induced RBL-2H3 cells and mast cell degranulation in IgE + DNP-BSA-induced RBL-2H3 cells. Our study indicates that DCE and two compounds (7,8-dimethoxyflavone and 7,2'-dimethoxyflavone) might effectively improve inflammatory and atopic skin symptoms.

Systematic comparisons of various markers for mast cell activation in RBL-2H3 cells

Mast cell activation plays a key role in various allergic diseases and anaphylaxis. Several methods/techniques can be used for detection of mast cell activation. However, there was no previous systematic evaluation to compare the efficacy of each method/technique. The present study thus systematically compared various markers for mast cell activation induced by IgE cross-linking. The widely used RBL-2H3 mast cells were sensitized with anti-DNP (dinitrophenyl) IgE overnight and activated with DNP-BSA (bovine serum albumin) for up to 4 h. The untreated cells and those with anti-DNP IgE sensitization but without DNP-BSA activation served as the controls. Intracellular calcium level gradually increased to ~2-fold at 1 h, reached its peak (~5-fold) at 2 h, and returned to the basal level at 3-h post-activation. The increases in cellular tryptase level (by Western blotting) (~0.3- to 0.4-fold) and average cell size (~2.5-fold) and decrease of nucleus/cytoplasm ratio (~0.4- to 0.5-fold) were marginal at all time-points. By contrast, β-hexosaminidase release and CD63 expression (by both flow cytometry and immunofluorescence detection/localization), secreted tryptase level (by Western blotting), and tryptase expression (by immunofluorescence detection/localization) stably and obviously increased (~10-fold as compared with the untreated control and sensitized-only cells or detectable only after activation). Based on these data, the stably obvious increases (by ≥ 10-fold) in β-hexosaminidase release, CD63 expression (by both flow cytometry and immunofluorescence staining), secreted tryptase level (by Western blotting), and tryptase expression (by immunofluorescence staining) are recommended as the markers of choice for the in vitro study of mast cell activation using RBL-2H3 cells.

Functionality of a bicistronic construction containing HEXA and HEXB genes encoding β-hexosaminidase A for cell-mediated therapy of GM2 gangliosidoses

Tay-Sachs disease and Sandhoff disease are severe hereditary neurodegenerative disorders caused by a deficiency of β-hexosaminidase A (HexA) enzyme, which results in the accumulation of GM2 gangliosides in the nervous system cells. In this work, we analyzed the efficacy and safety of cell-mediated gene therapy for Sandhoff disease and Sandhoff disease using a bicistronic lentiviral vector encoding cDNA of HexA α- and β-subunit genes separated by the nucleotide sequence of a P2A peptide (HEXA-HEXB). The functionality of the bicistronic construct containing the HEXA-HEXB genetic cassette was analyzed in a culture of HEK293T cells and human umbilical cord blood mononuclear cells (hUCBMCs). Our results showed that the enzymatic activity of HexA in the conditioned medium harvested from genetically modified HEK293T-HEXA-HEXB and hUCBMCs-HEXA-HEXB was increased by 23 and 8 times, respectively, compared with the conditioned medium of native cells. Western blot analysis showed that hUCBMCs-HEXA-HEXB secreted both completely separated HEXA and HEXB proteins, and an uncleaved protein containing HEXA + HEXB linked by the P2A peptide. Intravenous injection of genetically modified hUCBMCs-HEXA-HEXB to laboratory Wistar rats was carried out, and the HexA enzymatic activity in the blood plasma of experimental animals, as well as the number of live cells of immune system organs (spleen, thymus, bone marrow, lymph nodes) were determined. A significant increase in the enzymatic activity of HexA in the blood plasma of laboratory rats on days 6 and 9 (by 2.5 and 3 times, respectively) after the administration of hUCBMCs-HEXA-HEXB was shown. At the same time, the number of live cells in the studied organs remained unchanged. Thus, the functionality of the bicistronic genetic construct encoding cDNA of the HEXA and HEXB genes separated by the nucleotide sequence of the P2A peptide was shown in vitro and in vivo. We hypothesize that due to the natural ability of hUCBMCs to overcome biological barriers, such a strategy can restore the activity of the missing enzyme in the central nervous system of patients with GM2 gangliosidoses. Based on the obtained data, it can be concluded that intravenous administration of hUCBMCs with HexA overexpression is a promising method of the therapy for GM2 gangliosidoses. The animal protocol was approved by the Animal Ethics Committee of the Kazan Federal University (No. 23) on June 30, 2020.

Anti-allergic Inflammatory Components from the Leaves of Piper crocatum Ruiz & Pav

Piper crocatum Ruiz & Pav. (P. crocatum), a traditional medicinal plant, has been shown to possess various pharmacological activities, including anticancer activity, antioxidant activity, antibacterial activity, anti-hyperglycemic activity, anti-allergic inflammatory activity and others. To identify the potential anti-allergic inflammatory effective constituents of P. crocatum, 13 single compounds were isolated from the methanol extract of P. crocatum leaves, and their structures were identified by contrasting their NMR spectroscopic data and previously published papers. First, the anti-allergic inflammatory activities of these single compounds were examined by accessing immune function related biomarkers such as nitric oxide (NO) and β-hexosaminidase. We found that the methanol extract and catechaldehyde (compound 1) potently suppressed NO production. Additionally, Western blot analysis showed that P. crocatum methanol extract and compound 1 suppressed the production of NO by reducing inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Consistent with these observations, P. crocatum methanol extract and compound 1 remarkably decreased β-hexosaminidase release from RBL-2H3 cells stimulated with 2,4-dinitrophenylated bovine serum albumin (DNP-BSA)-specific immunoglobulin E (IgE) antibodies. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay indicated that P. crocatum methanol extract and compound 1 exhibited no cytotoxicity to RAW264.7 and RBL-2H3 cells. Based on these findings, compound 1 is suggested as an active anti-allergic inflammatory component of P. crocatum.

Decrease in Myelin-Associated Lipids Precedes Neuronal Loss and Glial Activation in the CNS of the Sandhoff Mouse as Determined by Metabolomics

Sandhoff disease (SD) is a lysosomal disease caused by mutations in the gene coding for the β subunit of β-hexosaminidase, leading to deficiency in the enzymes β-hexosaminidase (HEX) A and B. SD is characterised by an accumulation of gangliosides and related glycolipids, mainly in the central nervous system, and progressive neurodegeneration. The underlying cellular mechanisms leading to neurodegeneration and the contribution of inflammation in SD remain undefined. The aim of the present study was to measure global changes in metabolism over time that might reveal novel molecular pathways of disease. We used liquid chromatography-mass spectrometry and ¹H Nuclear Magnetic Resonance spectroscopy to profile intact lipids and aqueous metabolites, respectively. We examined spinal cord and cerebrum from healthy and Hexb ^-/- mice, a mouse model of SD, at ages one, two, three and four months. We report decreased concentrations in lipids typical of the myelin sheath, galactosylceramides and plasmalogen-phosphatidylethanolamines, suggesting that reduced synthesis of myelin lipids is an early event in the development of disease pathology. Reduction in neuronal density is progressive, as demonstrated by decreased concentrations of N-acetylaspartate and amino acid neurotransmitters. Finally, microglial activation, indicated by increased amounts of myo-inositol correlates closely with the late symptomatic phases of the disease.

Inhibitory Effects of Green Asparagus Extract, Especially Phospholipids, on Allergic Responses in Vitro and in Vivo

Asparagus (Asparagus officinalis L.) is one of the widely consumed vegetables. To investigate the mechanism underlying the anti-allergic responses of asparagus, we extracted different fractions from asparagus and measured their inhibitory effects on β-hexosaminidase release in RBL-2H3 cells in vitro and an atopic dermatitis NC/Nga mouse model in vivo. The lipid fractions from asparagus were extracted with 50% ethanol, separated using chloroform by liquid-liquid phase separation, and fractionated by solid-phase extraction. Among them, acetone fraction (rich in glycolipid) and MeOH fraction (rich in phospholipid) markedly inhibited β-hexosaminidase release from RBL-2H3 cells. In NC/Nga mice treated with picryl chloride, atopic dermatitis was alleviated following exposure to the 50% EtOH extract, acetone fraction, and methanol fraction. The inhibitory effects of asparagus fractions in vivo were supported by the significant decrease in serum immunoglobulin E (IgE) levels. The phospholipid fractions showed significantly better inhibitory effects, and phosphatidic acid from this fraction showed the best inhibitory effect on β-hexosaminidase release. In mice challenged with ovalbumin (OVA), oral administration of asparagus extract and its fractions decreased the OVA-specific IgE level and total IgE, indicating that these effects may be partly mediated through the downregulation of antigen-specific IgE production. Taken together, the present study shows for the first time that asparagus extract and its lipid fractions could potentially mitigate allergic reactions by decreasing degranulation in granulocytes. Our study provides useful information to develop nutraceuticals and functional foods fortified with asparagus.

Lactobacillus plantarum 22A-3 exerts anti-allergic activity through TGF-β secretion in passive cutaneous anaphylaxis of mice

Allergy is a global issue, however, medical intervention for allergy treatment is limited. Recent studies have focussed on allergy prevention with food factors. In this study, Lactobacillus plantarum 22 A-3 (LP22A3) exerted an anti-allergic effect in passive cutaneous anaphylaxis (PCA) reaction and increased transforming growth factor (TGF)-β contents in blood. The increase of TGF-β contents in blood by exogenous TGF-β injection intraperitoneally decreased Evans blue release into mice ears to the same level as LP22A3 treatment in PCA reaction. LP22A3 treatment directly to RBL-2H3 cells shows no effect on β-hexosaminidase release from RBL-2H3 but inhibited its release using the Caco-2/RBL-2H3 cells co-culture system stimulated with LP22A3 from the apical side. Moreover, TGF-β treatment to RBL-2H3 inhibited β-hexosaminidase release from RBL-2H3. However, β-hexosaminidase release was cancelled by TGF-β neutralising antibody without the influence of TGF-β mRNA expression in Caco-2 cells. These results showed that LP22A3 ameliorates allergy by TGF-β secretion through the intestine.

Liquid Chromatography Tandem Mass Spectrometry Based Label-Free Quantification Method for Assessment of Allergen-Induced Anaphylactoid Reactions

Mast cells are essential in mediating inflammatory processes. When activated, mast cells can rapidly release characteristic granules and various mediators into the interstitium. Tryptase (TPS) and β-hexosaminidase (HEXB) are typical protease mediators stored in granules and released upon activation. They have been recognized as important biomarkers of anaphylaxis, and the released level is associated with the severity of allergic reactions. In this study, a sensitive, accurate, and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneously quantifying the two biomarkers was developed and validated in LAD2 cell culture supernatant, and P₁₄R was used as internal standard. Good linearity was observed in the range of 50-2500 ng/mL for TPS and 10-2000 ng/mL for HEXB both with R² > 0.99. The matrix effect and recovery were both within acceptable limits. We quantified TPS and HEXB released from Laboratory of Allergic Disease 2 (LAD2) mast cells treated with several potential allergens, and the results demonstrate that the method can be used to investigate TPS and HEXB levels in LAD2 mast cell model during allergy research. We anticipate our approach to be a robust and sensitive assessment method for more biomarkers with similar kinetics characteristics and to be a major tool of allergic drug assessment or antiallergic drug development in research.

Melanogenesis Inhibitors from the Endophytic Fungus Aspergillus amstelodami

Two new compounds, named 3,4-dimethoxyphenyl α-d-ribofuranoside (1) and 3β-(β-d-glucopyranosyloxy)olean-12-ene-23,28,30-trioic acid (2), together with thirteen known compounds, were isolated from the white beans culture of the marine derived endophytic fungus Aspergillus amstelodami. Structure elucidation of the new compounds was carried out by one-, two-dimensional spectroscopy, and high resolution electrospray ionization mass. The antimelanogenic and anti-allergic activity of the isolated compounds were investigated. Compounds 4, 7, 1, 3, 11, 6 and 9 selectively suppressed melanin production in B16 melanoma cells, using arbutin as a positive control. Their IC₅₀ values were 30.8±5.57, 38.5±6.08, 52.6±6.64, 98.0±1.16, 100.4±3.05, 112.0±0.22 and 144.7±2.35 μm, respectively, while that of arbutin was 151.7±1.27 μm. The tested compounds did not show any significant anti-allergic activity in RBL-2H3 cells, as compared to quercetin.

Lamiaceae: An Insight on Their Anti-Allergic Potential and Its Mechanisms of Action

The prevalence of allergic diseases such as asthma, allergic rhinitis, food allergy and atopic dermatitis has increased dramatically in recent decades. Conventional therapies for allergy can induce undesirable effects and hence patients tend to seek alternative therapies like natural compounds. Considering the fact above, there is an urgency to discover potential medicinal plants as future candidates in the development of novel anti-allergic therapeutic agents. The Lamiaceae family, or mint family, is a diverse plant family which encompasses more than 7,000 species and with a cosmopolitan distribution. A number of species from this family has been widely employed as ethnomedicine against allergic inflammatory skin diseases and allergic asthma in traditional practices. Phytochemical analysis of the Lamiaceae family has reported the presence of flavonoids, flavones, flavanones, flavonoid glycosides, monoterpenes, diterpenes, triterpenoids, essential oil and fatty acids. Numerous investigations have highlighted the anti-allergic activities of Lamiaceae species with their active principles and crude extracts. Henceforth, this review has the ultimate aim of compiling the up-to-date (2018) findings of published scientific information about the anti-allergic activities of Lamiaceae species. In addition, the botanical features, medicinal uses, chemical constituents and toxicological studies of Lamiaceae species were also documented. The method employed for data collection in this review was mainly the exploration of the PubMed, Ovid and Scopus databases. Additional research studies were obtained from the reference lists of retrieved articles. This comprehensive summarization serves as a useful resource for a better understanding of Lamiaceae species. The anti-allergic mechanisms related to Lamiaceae species are also reviewed extensively which aids in future exploration of the anti-allergic potential of Lamiaceae species.

Dampening of mast cell secondary responses to allergen involves specific signalling and epigenetic changes

Allergic diseases are increasing worldwide. Allergen and IgE dependent mast cell (MC) activation is the major initiator of these clinical symptoms. During this study, the effect of multiple exposures to the same allergen, on MC degranulation was studied. First, MC recovery in terms of surface expression of high affinity receptor FcεRI, and granule content after a primary allergen challenge was confirmed. Overall, previous exposure of MCs to allergen challenge led to a significant reduction in pre-stored mediator release during the secondary challenge at various time points and with various doses of allergen in vitro. The dampened response was not due to any defects in very early steps in signalling involving FcεRI activation. Inhibition of dampening response during secondary challenge by various inhibitors like wortmannin, tranylcypromine and pargyline, indicated the involvement of PI3K signalling and chromatin modifications. Our study provides insight into new therapeutic avenues for treating allergic disorders targeting MCs.

Antiallergic Activity of the Wild Mushrooms of Nepal and the Pure Compound Hispidin

In the present study, ethanol extracts of 90 wild mushroom samples from Nepal, and the pure compound hispidin, were screened for their ability to inhibit β-hexosaminidase release (BHR) from rat basophilic leukemia-2H3 cells. Simultaneously, the toxicity of the extracts toward the cells was also determined, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Samples belonging to the groups Hymenochaetales and Polyporales showed promising anti-allergic activity, with Phellinus adamantinus and Ganoderma lingzhi 3 allowing a mere 19.4% and 16.7% BHR, respectively, without any cell cytotoxicity. Moreover, the 50% inhibitory concentration (IC₅₀) values for Inonotus clemensiae and P. adamantinus were determined to be 51.24 and 50.65 μg/mL, respectively; whereas hispidin, the major bioactive compound in I. clemensiae showed an IC₅₀ value of 82.47 μg/mL. These findings are crucial in underscoring the medicinal value of the wild mushrooms of Nepal, as a source of strong antiallergic agents.

New Approaches to Tay-Sachs Disease Therapy

Tay-Sachs disease belongs to the group of autosomal-recessive lysosomal storage metabolic disorders. This disease is caused by β-hexosaminidase A (HexA) enzyme deficiency due to various mutations in α-subunit gene of this enzyme, resulting in GM2 ganglioside accumulation predominantly in lysosomes of nerve cells. Tay-Sachs disease is characterized by acute neurodegeneration preceded by activated microglia expansion, macrophage and astrocyte activation along with inflammatory mediator production. In most cases, the disease manifests itself during infancy, the “infantile form,” which characterizes the most severe disorders of the nervous system. The juvenile form, the symptoms of which appear in adolescence, and the most rare form with late onset of symptoms in adulthood are also described. The typical features of Tay-Sachs disease are muscle weakness, ataxia, speech, and mental disorders. Clinical symptom severity depends on residual HexA enzymatic activity associated with some mutations. Currently, Tay-Sachs disease treatment is based on symptom relief and, in case of the late-onset form, on the delay of progression. There are also clinical reports of substrate reduction therapy using miglustat and bone marrow or hematopoietic stem cell transplantation. At the development stage there are methods of Tay-Sachs disease gene therapy using adeno- or adeno-associated viruses as vectors for the delivery of cDNA encoding α and β HexA subunit genes. Effectiveness of this approach is evaluated in α or β HexA subunit defective model mice or Jacob sheep, in which Tay-Sachs disease arises spontaneously and is characterized by the same pathological features as in humans. This review discusses the possibilities of new therapeutic strategies in Tay-Sachs disease therapy aimed at preventing neurodegeneration and neuroinflammation.

Anti-allergic activity of mung bean (Vigna radiata (L.) Wilczek) protein hydrolysates produced by enzymatic hydrolysis using non-gastrointestinal and gastrointestinal enzymes

Mung bean seed is a well-known plant protein consumed in Asian countries but the protein is usually retrieved as a waste product during starch production. This study investigated the anti-allergic property of mung bean protein hydrolysates (MBPH) produced by enzymatic hydrolysis using non-gastrointestinal (non-GI), GI and a combination of non-GI+GI enzymes. The hydrolysates were investigated for any anti-allergic property by detecting the amount of β-hexosaminidase released in RBL-2H3 cells, and complemented with the MTT assay to show cell viability. It was found that MBPH hydrolyzed by a combination of flavourzyme (non-GI enzyme) and pancreatin (GI enzyme) exhibited the highest anti-allergic activity (135.61%), followed by those produced with alcalase, a non-GI enzyme (121.74%) and 80.32% for pancreatin (GI enzyme). Minimal toxicity (<30%) of all hydrolysates on RBL-2H3 cells line was observed. The results suggest that MBPH can potentially serve as a hypoallergenic food ingredient or supplement. PRACTICAL APPLICATIONS: Mung bean (Vigna radiata L. (Wilczek)) is also known as "green gram" and it is an excellent source of protein. The major mung bean storage proteins are the globulin, albumin and legumin, which are also referred to as legume allergens. Our study showed that mung bean peptides obtained after enzymatic hydrolysis influenced β-hexosaminidase inhibition without any toxic effect on RBL-2H3 cells. This indicates that mung bean allergenicity can be reduced after enzymatic hydrolysis and the protein hydrolysates could be as a hypoallergic food, ingredient, supplement and/or protein substitute in the formulation of food products.

Comparison of Allergic Parameters between Whey Protein Concentrate and Its Hydrolysate in Rat Basophilic Leukemia (RBL)-2H3 Cells

This study was conducted to compare the anti-allergic effects of a whey protein concentrate (WPC) and WPC hydrolysate. WPC hydrolysate was prepared using enzymatic digestion for 8 h with trypsin and α-chymotrypsin, after which it was freeze-dried. The allergic parameters assessed in rat basophilic leukemia (RBL)-2H3 cells were degranulation and release of β-hexosaminidase, release of tumor necrosis factor (TNF)-α, and changes in the expression of IL-1β, IL-4, and IL-10 by real time polymerase chain reaction (PCR). During preparation of the WPC hydrolysate, hydrolysis increased rapidly from 0 to 10 min and then gradually increased slowly from 1 h onwards, achieving a final degree of hydrolysis of 78.50%. The SDS-PAGE analysis revealed a reduction in the intensity of several protein bands in the WPC hydrolysate compared to the WPC. IgE-induced β-hexosaminidase release from RBL-2H3 cells was decreased to a higher degree following treatment with the hydrolysate compared to WPC treatment. W500 (500 µg/mL WPC) showed the least inhibition of β-hexosaminidase release, but there was no significant difference between W500 and W1000 (1,000 µg/mL) (p<0.05). H1000 (1,000 µg/mL WPC hydrolysate) inhibited β-hexosaminidase release by 39%. Compared to the control, treatment with H1000 decreased TNF-α secretion to 11.87 pg/mL. The gene expression levels of IL-1β, IL-4, and IL-13 were all significantly decreased in hydrolysate (p<0.05). In the case of IL-1β and IL-4, the expression levels in W1000 treated cells were decreased by 73.67% and 65%, respectively, and that of IL-13 was decreased by 66.43% compared to the control.

Characterization of Brain Lysosomal Activities in GBA-Related and Sporadic Parkinson's Disease and Dementia with Lewy Bodies

Mutations in the GBA gene, encoding the lysosomal hydrolase glucocerebrosidase (GCase), are the most common known genetic risk factor for Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). The present study aims to gain more insight into changes in lysosomal activity in different brain regions of sporadic PD and DLB patients, screened for GBA variants. Enzymatic activities of GCase, β-hexosaminidase, and cathepsin D were measured in the frontal cortex, putamen, and substantia nigra (SN) of a cohort of patients with advanced PD and DLB as well as age-matched non-demented controls (n = 15/group) using fluorometric assays. Decreased activity of GCase (− 21%) and of cathepsin D (− 15%) was found in the SN and frontal cortex of patients with PD and DLB compared to controls, respectively. Population stratification was applied based on GBA genotype, showing substantially lower GCase activity (~ − 40%) in GBA variant carriers in all regions. GCase activity was further significantly decreased in the SN of PD and DLB patients without GBA variants in comparison to controls without GBA variants. Our results show decreased GCase activity in brains of PD and DLB patients with and without GBA variants, most pronounced in the SN. The results of our study confirm findings from previous studies, suggesting a role for GCase in GBA-associated as well as sporadic PD and DLB.

Canine GM2-Gangliosidosis Sandhoff Disease Associated with a 3-Base Pair Deletion in the HEXB Gene

BACKGROUND

GM2-gangliosidosis is a fatal neurodegenerative lysosomal storage disease (LSD) caused by deficiency of either β-hexosaminidase A (Hex-A) and β-hexosaminidase B (Hex-B) together, or the GM2 activator protein. Clinical signs can be variable and are not pathognomonic for the specific, causal deficiency.

OBJECTIVES

To characterize the phenotype and genotype of GM2-gangliosidosis disease in an affected dog.

ANIMALS

One affected Shiba Inu and a clinically healthy dog.

METHODS

Clinical and neurologic evaluation, brain magnetic resonance imaging (MRI), assays of lysosomal enzyme activities, and sequencing of all coding regions of HEXA, HEXB, and GM2A genes.

RESULTS

A 14-month-old, female Shiba Inu presented with clinical signs resembling GM2-gangliosidosis in humans and GM1-gangliosidosis in the Shiba Inu. Magnetic resonance imaging (MRI) of the dog's brain indicated neurodegenerative disease, and evaluation of cerebrospinal fluid (CSF) identified storage granules in leukocytes. Lysosomal enzyme assays of plasma and leukocytes showed deficiencies of Hex-A and Hex-B activities in both tissues. Genetic analysis identified a homozygous, 3-base pair deletion in the HEXB gene (c.618-620delCCT).

CONCLUSIONS AND CLINICAL IMPORTANCE

Clinical, biochemical, and molecular features are characterized in a Shiba Inu with GM2-gangliosidosis. The deletion of 3 adjacent base pairs in HEXB predicts the loss of a leucine residue at amino acid position 207 (p.Leu207del) supporting the hypothesis that GM2-gangliosidosis seen in this dog is the Sandhoff type. Because GM1-gangliosidosis also exists in this breed with almost identical clinical signs, genetic testing for both GM1- and GM2-gangliosidosis should be considered to make a definitive diagnosis.

Sujiaonori-Derived Algal Biomaterials Inhibit Allergic Reaction in Allergen-Sensitized RBL-2H3 Cell Line and Improve Skin Health in Humans

Sujiaonori, a river alga growing in the Kochi prefecture, Japan, contains several bioactive compounds such as sulfated polysaccharides (ulvans), ω-3 fatty acids, and vitamins. Dietary intake of this alga-based supplement has been reported to increase circulatory adiponectin, a salutary hormone that is reported to be associated with healthy longevity and prevents a number of cardiovascular and metabolic disorders. This report highlights the anti-allergic and skin health enhancing effects of Sujiaonori-derived ulvan (Tosalvan) and supplement, respectively. RBL-2H3 cell line was used to investigate the anti-allergic effect of algal SP through the evaluation of β-hexosaminidase activity. Algal sulfated polysaccharides or SP (Tosalvan, Yoshino SP) were extracted from powders of dried alga samples provided by local food manufacturers. Report on the effect of daily dietary intake of Sujiaonori-based supplement on skin health is part of a four-week clinical investigation that, in comparison with a supplement made of 70% corn starch powder and 30% spinach powder mixture (twice 3 g daily), explore the beneficial effects of Sujiaonori algal biomaterial (SBM; 3 g taken twice daily) on cardiovascular, gastrointestinal and skin health in a sample of Japanese women. Transepidermal water loss (TEWL) was the skin health marker used in this study and was measured with the use of a corneometer. Significant reduction of β-hexosaminidase activity was observed in Tosalvan and Yoshino SP-treated cells (vs. control; p < 0.05), whereas dietary intake of SBM markedly reduced TEWL level after four weeks of supplementation, as compared to baseline TEWL (p < 0.001). Additionally, SBM improved TEWL better than the control product (p < 0.001). Findings contained in this report suggest that Sujiaonori-derived Tosalvan and Yoshino SP have anti-allergic potential and that the dietary intake of SBM has a beneficial effect on skin health.

PUGNAc treatment provokes globotetraosylceramide accumulation in human umbilical vein endothelial cells

PUGNAc is a well-investigated inhibitor for protein-O-GlcNAcase, whereas recent investigations showed that PUGNAc had a broad range as inhibitor for cellular β-hexosaminidases. Here we report that PUGNAc treatment provokes globotetraosylceramide (Gb4Cer) accumulation in human umbilical vein endothelial cells (HUVEC). HPLC analysis and a quantitative ELISA using newly developed anti-Gb4Cer monoclonal antibody revealed that PUGNAc treatment specifically increased the expression of Gb4Cer among glycosphingolipids expressed in HUVEC. Although the effect was weaker than PUGNAc, an O-GlcNAcase selective inhibitor (Thiamet-G) treatment also increased Gb4Cer levels in HUVEC. Furthermore, both of PUGNAc and Thiamet-G treatment up-regulated the expression levels of α-1,4-galactosyltransferase/Gb3Cer synthase gene which encodes a key enzyme in Gb4Cer synthesis. These results indicate that protein-O-GlcNAcylation can regulate the expression levels of cellular Gb4Cer.

Clinical,biochemical and molecular analysis of five Chinese patients with Sandhoff disease

Sandhoff disease (SD) is a rare autosomal recessive lysosomal storage disorder of sphingolipid metabolism resulting from the deficiency of β-hexosaminidase (HEX). Mutations of the HEXB gene cause Sandhoff disease. In order to improve the diagnosis and expand the knowledge of the disease, we collected and analyzed relevant data of clinical diagnosis, biochemical investigation, and molecular mutational analysis in five Chinese patients with SD. The patients presented with heterogenous symptoms of neurologic deterioration. HEX activity in leukocytes was severely deficient. We identified seven different mutations, including three known mutations: IVS12-26G > A, p.T209I, p.I207V, and four novel mutations: p.P468PfsX62, p.L223P, p.Y463X, p.G549R. We also detected two different heterozygous mutations c.-122delC and c.-126C > T in the promoter which were suspected to be deleterious mutations. We attempted to correlate these mutations with the clinical presentation of the patients. Our study indicates that the mutation p.T209I and p.P468PfsX62 may link to the infantile form of SD. Our study expands the spectrum of genotype of SD in China, provides new insights into the molecular mechanism of SD and helps to the diagnosis and treatment of this disease.

Combined replacement effects of human modified β-hexosaminidase B and GM2 activator protein on GM2 gangliosidoses fibroblasts

GM2 gangliosidoses are autosomal recessive lysosomal storage diseases (LSDs) caused by mutations in the HEXA, HEXB and GM2A genes, which encode the human lysosomal β-hexosaminidase (Hex) α- and β-subunits, and GM2 activator protein (GM2A), respectively. These diseases are associated with excessive accumulation of GM2 ganglioside (GM2) in the brains of patients with neurological symptoms. Here we established a CHO cell line overexpressing human GM2A, and purified GM2A from the conditioned medium, which was taken up by fibroblasts derived from a patient with GM2A deficiency, and had the therapeutic effects of reducing the GM2 accumulated in fibroblasts when added to the culture medium. We also demonstrated for the first time that recombinant GM2A could enhance the replacement effect of human modified HexB (modB) with GM2-degrading activity, which is composed of homodimeric altered β-subunits containing a partial amino acid sequence of the α-subunit, including the GSEP loop necessary for binding to GM2A, on reduction of the GM2 accumulated in fibroblasts derived from a patient with Tay-Sachs disease, a HexA (αβ heterodimer) deficiency, caused by HEXA mutations. We predicted the same manner of binding of GM2A to the GSEP loop located in the modified HexB β-subunit to that in the native HexA α-subunit on the basis of the x-ray crystal structures. These findings suggest the effectiveness of combinational replacement therapy involving the human modified HexB and GM2A for GM2 gangliosidoses.

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Purification of recombinant human GM2A proteins by CHO cell line overexpressing GM2A.

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Reduction of GM2 accumulated in GM2A deficiency fibroblasts by GM2A replacement.

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Combined effects of modified HexB and GM2A for HexA deficiency fibroblasts.

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In silico prediction of molecular interaction between modified HexB and GM2A.

AAV-mediated gene delivery in a feline model of Sandhoff disease corrects lysosomal storage in the central nervous system

Sandhoff disease (SD) is an autosomal recessive neurodegenerative disease caused by a mutation in the gene for the β-subunit of β-N-acetylhexosaminidase (Hex), resulting in the inability to catabolize ganglioside GM2 within the lysosomes. SD presents with an accumulation of GM2 and its asialo derivative GA2, primarily in the central nervous system. Myelin-enriched glycolipids, cerebrosides and sulfatides, are also decreased in SD corresponding with dysmyelination. At present, no treatment exists for SD. Previous studies have shown the therapeutic benefit of adeno-associated virus (AAV) vector-mediated gene therapy in the treatment of SD in murine and feline models. In this study, we treated presymptomatic SD cats with AAVrh8 vectors expressing feline Hex in the thalamus combined with intracerebroventricular (Thal/ICV) injections. Treated animals showed clearly improved neurologic function and quality of life, manifested in part by prevention or attenuation of whole-body tremors characteristic of untreated animals. Hex activity was significantly elevated, whereas storage of GM2 and GA2 was significantly decreased in tissue samples taken from the cortex, cerebellum, thalamus, and cervical spinal cord. Treatment also increased levels of myelin-enriched cerebrosides and sulfatides in the cortex and thalamus. This study demonstrates the therapeutic potential of AAV for feline SD and suggests a similar potential for human SD patients.

Neolignan inhibitors of antigen-induced degranulation in RBL-2H3 cells from the needles of Pinus thunbergii

The ethanolic extract of the needles of Pinus thunbergii was found to suppress antigen mediated degranulation of rat basophilic leukemia (RBL-2H3) cells. A new neolignan glycoside, named pinusthunbergiside A (1), as well as six known neolignan glycosides (2-7) were isolated from the ethanolic extract using bioassay-guided fractionation. Their structures were elucidated by a combination of 1D and 2D NMR, HRESI-MS, and circular dichroism (CD) data. Compounds 2-7 were found for the first time in this plant. The inhibitory effects of isolated constituents on the release of β-hexosaminidase from RBL-2H3 cells were examined, and compounds 2, 3, 5, and 6 were found to show the inhibitory activity with IC₅₀ values ranging between 52.3 and 75.3 μM.

Effects of Echium plantagineum L. bee pollen on basophil degranulation: relationship with metabolic profile

This study aimed to evaluate the anti-allergic potential of Echium plantagineum L. bee pollen and to characterize its primary metabolites. The activity of E. plantagineum hydromethanolic extract, devoid of alkaloids, was tested against β-hexosaminidase release in rat basophilic leukemic cells (RBL-2H3). Two different stimuli were used: calcium ionophore A23187 and IgE/antigen. Lipoxygenase inhibitory activity was evaluated in a cell-free system using soybean lipoxygenase. Additionally, the extract was analysed by HPLC-UV for organic acids and by GC-IT/MS for fatty acids. In RBL-2H3 cells stimulated either with calcium ionophore or IgE/antigen, the hydromethanolic extract significantly decreased β-hexosaminidase release until the concentration of 2.08 mg/mL, without compromising cellular viability. No effect was found on lipoxygenase. Concerning extract composition, eight organic acids and five fatty acids were determined for the first time. Malonic acid (80%) and α-linolenic acid (27%) were the main compounds in each class. Overall, this study shows promising results, substantiating for the first time the utility of intake of E. plantagineum bee pollen to prevent allergy and ameliorate allergy symptoms, although a potentiation of an allergic response can occur, depending on the dose used.

Effects of magnolialide isolated from the leaves of Laurus nobilis L. (Lauraceae) on immunoglobulin E-mediated type I hypersensitivity in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Laurus nobilis L. (Lauraceae) has been used for folk medicines in the Mediterranean area and Europe to treat various disorders including skin inflammation (dermatitis) and asthma.

AIM OF THE STUDY

Our aim was to investigate the scientific evaluation of the compounds from Laurus nobilis L. on immuniglobulin E (IgE)-mediated type I hypersensitivity responses in vitro such as atopic dermatitis and asthma.

METHODS AND MATERIALS

Seven compounds were isolated and examined for the mast cell stabilizing effect on IgE-sensitized RBL-2H3 mast cells by measuring the β-hexosaminidase activity. In addition, the effects on interleukin (IL)-4 production and IL-5-dependent Y16 early B cell proliferation were investigated as well as their cytotoxic effects on RBL-2H3 cells.

RESULTS

Among the seven isolated compounds, magnolialide attenuated the release of β-hexosaminidase from RBL-2H3 cells with an IC50 value of 20.2 μM, while the other compounds revealed no significant effects at concentrations tested. Furthermore, magnolialide significantly inhibited the IL-4 release with an IC50 value of 18.1 μM and IL-4 mRNA expression with an IC50 value of 15.7 μM in IgE-sensitized RBL-2H3 cells. In addition, the inhibition of IL-5-dependent proliferation of early B cells (Y16 cells) by magnolialide was demonstrated with an IC50 value of 18.4 μM.

CONCLUSION

These results suggest that the magnolialide might be a candidate for the treatment of IgE-mediated hypersensitivity responses such as atopic dermatitis and asthma by inhibiting mast cell degranulation, the IL-4 production, and IL-5-dependent early B cell proliferation, key factors in the development and amplification of type I hypersensitivity reactions.

Juvenile-onset motor neuron disease caused by novel mutations in β-hexosaminidase

A 12 year-old female presented with a seven-year history of progressive muscle weakness, atrophy, tremor and fasciculations. Cognition was normal. Rectal biopsy revealed intracellular storage material and biochemical testing indicated low hexosaminidase activity consistent with juvenile-onset G(M2)-gangliosidosis. Genetic evaluation revealed compound heterozygosity with two novel mutations in the hexosaminidase β-subunit (c.512-3 C>A and c.1613+15_1613+18dup). Protein analysis was consistent with biochemical findings and indicated only a small portion of β-subunits were properly processed. These results provide additional insight into juvenile-onset G(M2)-gangliosidoses and further expand the number of β-hexosaminidase mutations associated with motor neuron disease.

Inhibitory effects of costunolide isolated from Laurus nobilis on IgE-induced degranulation of mast cell-like RBL-2H3 cells and the growth of Y16 pro-B cells

This study investigated the inhibitory effects of costunolide isolated from the leaves of Laurus nobilis L. (Lauraceae) on basophil-mediated allergic reactions and interleukin (IL)-5-mediated B cell growth. The effects of costunolide on β-hexosaminidase (a key parameter of degranulation) release and IL-4 expression in rat basophilic leukemia (RBL-2H3) cells were determined by measuring β-hexosaminidase activity and by semi-quantitative RT-PCR, respectively. The effects of costunolide on Y16 pro-B cell viability and growth were determined by 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. Costunolide was found significantly to inhibit β-hexosaminidase activity (p < 0.01) and IL-4 transcription in RBL-2H3 cells in a dose-dependent manner. Its 50% inhibitory concentration (IC50 ) was 34 µM, while that of the positive control, ketotifen, was 24 µM (IL-4 mRNA transcription). Moreover, costunolide dose-dependently suppressed pro-B cell growth in IL-5-stimulated Y16 cells. These results provide evidence that costunolide stabilizes mast cells by inhibiting IgE-mediated degranulation and inhibits IL-5-stimulated B cell growth.

Environmental estrogens induce mast cell degranulation and enhance IgE-mediated release of allergic mediators

BACKGROUND

Prevalence and morbidity of allergic diseases have increased over the last decades. Based on the recently recognized differences in asthma prevalence between the sexes, we have examined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic pollutants have estrogen-like activities and are termed environmental estrogens. These pollutants tend to degrade slowly in the environment and to bioaccumulate and bioconcentrate in the food chain; they also have long biological half-lives.

OBJECTIVES

Our goal in this study was to identify possible pathogenic roles for environmental estrogens in the development of allergic diseases.

METHODS

We screened a number of environmental estrogens for their ability to modulate the release of allergic mediators from mast cells. We incubated a human mast cell line and primary mast cell cultures derived from bone marrow of wild type and estrogen receptor alpha (ER-alpha)-deficient mice with environmental estrogens with and without estradiol or IgE and allergens. We assessed degranulation of mast cells by quantifying the release of beta-hexosaminidase.

RESULTS

All of the environmental estrogens tested caused rapid, dose-related release of beta-hexosaminidase from mast cells and enhanced IgE-mediated release. The combination of physiologic concentrations of 17beta-estradiol and several concentrations of environmental estrogens had additive effects on mast cell degranulation. Comparison of bone marrow mast cells from ER-alpha-sufficient and ER-alpha-deficient mice indicated that much of the effect of environmental estrogens was mediated by ER-alpha.

CONCLUSIONS

Our findings suggest that estrogenic environmental pollutants might promote allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and exposure to allergens.

Enzymatic activities in traps of four aquatic species of the carnivorous genus Utricularia

•   Here, enzymatic activity of five hydrolases was measured fluorometrically in the fluid collected from traps of four aquatic Utricularia species and in the water in which the plants were cultured. •   In empty traps, the highest activity was always exhibited by phosphatases (6.1-29.8 µmol l^-1  h^-1 ) and β-glucosidases (1.35-2.95 µmol l^-1  h^-1 ), while the activities of α-glucosidases, β-hexosaminidases and aminopeptidases were usually lower by one or two orders of magnitude. Two days after addition of prey (Chydorus sp.), all enzymatic activities in the traps noticeably decreased in Utricularia foliosa and U. australis but markedly increased in Utricularia vulgaris. •   Phosphatase activity in the empty traps was 2-18 times higher than that in the culture water at the same pH of 4.7, but activities of the other trap enzymes were usually higher in the water. Correlative analyses did not show any clear relationship between these activities. •   Trap comensals (Euglena) could be partly responsible for production of some trap enzymes. The traps can produce phosphatases independently of catching prey. Taking into account the enzymatic activities in traps, phosphorus uptake from prey might be more important than that of nitrogen for the plants.

Synaptotagmin VII regulates Ca(2+)-dependent exocytosis of lysosomes in fibroblasts

Synaptotagmins (Syts) are transmembrane proteins with two Ca(2+)-binding C(2) domains in their cytosolic region. Syt I, the most widely studied isoform, has been proposed to function as a Ca(2+) sensor in synaptic vesicle exocytosis. Several of the twelve known Syts are expressed primarily in brain, while a few are ubiquitous (Sudhof, T.C., and J. Rizo. 1996. Neuron. 17: 379-388; Butz, S., R. Fernandez-Chacon, F. Schmitz, R. Jahn, and T.C. Sudhof. 1999. J. Biol. Chem. 274:18290-18296). The ubiquitously expressed Syt VII binds syntaxin at free Ca(2+) concentrations ([Ca(2+)]) below 10 microM, whereas other isoforms require 200-500 microM [Ca(2+)] or show no Ca(2+)-dependent syntaxin binding (Li, C., B. Ullrich, Z. Zhang, R.G.W. Anderson, N. Brose, and T.C. Sudhof. 1995. Nature. 375:594-599). We investigated the involvement of Syt VII in the exocytosis of lysosomes, which is triggered in several cell types at 1-5 microM [Ca(2+)] (Rodríguez, A., P. Webster, J. Ortego, and N.W. Andrews. 1997. J. Cell Biol. 137:93-104). Here, we show that Syt VII is localized on dense lysosomes in normal rat kidney (NRK) fibroblasts, and that GFP-tagged Syt VII is targeted to lysosomes after transfection. Recombinant fragments containing the C(2)A domain of Syt VII inhibit Ca(2+)-triggered secretion of beta-hexosaminidase and surface translocation of Lgp120, whereas the C(2)A domain of the neuronal- specific isoform, Syt I, has no effect. Antibodies against the Syt VII C(2)A domain are also inhibitory in both assays, indicating that Syt VII plays a key role in the regulation of Ca(2+)-dependent lysosome exocytosis.