HIV and SIV Envelope Glycoproteins Interact with Glycolipids and Lipids.

The present study demonstrates that, in addition to interacting with galactosylceramide (GalCer), HIV-1, HIV-2, and SIV envelope glycoproteins are able to interact with glucosylceramide (GlcCer), lactosylceramide (LacCer), and ceramide. These interactions were characterized by using three complementary approaches based on molecular binding and physicochemical assays. The binding assays showed that iodinated radiolabeled HIV-1 and HIV-2 glycoproteins (125I-gp) interact physically with GalCer, GlcCer, LacCer, and ceramide previously separated by thin layer chromatography (TLC) or directly coated on a flexible 96-well plate. These interactions are specific as demonstrated, on the one hand, by the dose-dependent inhibition in the presence of various dilutions of immune, but not non-immune, sera, and, on the other hand, by the absence of interaction of these glycolipids/lipids with 125I-IgG used as an unrelated control protein. These interactions were further confirmed in a physicochemical assay, based on the capacity of these glycolipids for insertion in a pre-established monomolecular film, as a model of the cell membrane, with each glycolipid/lipid. The addition of HIV envelope glycoproteins, but not ovomucoid protein used as a negative control, resulted in a rapid increase in surface pressure of the glycolipid/lipid films, thus indirectly confirming their interactions with GalCer, GlcCer, LacCer, and ceramide. In summary, we show that HIV and SIV envelope glycoproteins bind to GalCer, GlcCer, LacCer, and ceramide in a dose-dependent, saturable, and specific manner. These interactions may function as receptors of attachment in order to facilitate infection of CD4 low or negative cells or promote interactions with other receptors leading to the activation of signaling pathways or pathogenesis.

ß-Glucosylceramides and Tocopherols Regulate Development and Function of Dendritic Cells.

In humans and mice, offspring of allergic mothers are predisposed to development of allergy. In mice, allergic mothers have elevated ß-glucosylceramides (ßGlcCers) that are transported to the fetus via the placenta and to offspring via milk. The elevated ßGlcCers increase the number of fetal liver CD11c+CD11b+ dendritic cells (DCs) and offspring allergen-induced lung eosinophilia. These effects are modifiable by maternal dietary supplementation with the plant-derived lipids α-tocopherol and γ-tocopherol. It is not known whether ßGlcCers and tocopherols directly regulate development of DCs. In this study, we demonstrated that ßGlcCers increased development of GM-CSF-stimulated mouse bone marrow-derived DCs (BMDCs) in vitro without altering expression of costimulatory molecules. This increase in BMDC numbers was blocked by α-tocopherol and potentiated by γ-tocopherol. Furthermore, ßGlcCers increased protein kinase Cα (PKCα) and PKCδ activation in BMDCs that was blocked by α-tocopherol. In contrast, γ-tocopherol increased BMDC PKCα and PKCδ activation and enhanced the ßGlcCer-induced increase in PKCδ activation in a DC subset. Ag processing per DC was minimally enhanced in ßGlcCer-treated BMDCs and not altered ex vivo in lung DCs from pups of allergic mothers. Pups of allergic mothers had an increased proportion of CD11b+CD11c+ subsets of DCs, contributing to enhanced stimulation of T cell proliferation ex vivo. Thus, ßGlcCer, which is both necessary and sufficient for development of allergic predisposition in offspring of allergic mothers, directly increased development and PKC activation in BMDCs. Furthermore, this was modifiable by dietary tocopherols. This may inform design of future studies for the prevention or intervention in asthma and allergic disease.

Anti-melanogenic effects of glucosylceramides and elasticamide derived from rice oil by-products in melanoma cells, melanocytes, and human skin.

Glucosylceramides (GlcCer), which are present in many edible plants, suppress melanin production in mouse melanocytes. Rice GlcCer consist of multiple molecules that comprise different types of sphingoid bases as well as diverse lengths and stereotypes of free fatty acids. Adjacent to the GlcCer fraction, there are free ceramides (Cer) as minor constituents. However, the anti-melanogenic activities of individual GlcCer and Cer remain unknown. Therefore, we herein isolated 13 GlcCer and elasticamide, a Cer [AP] from the gummy by-products of rice bran oil, and examined their anti-melanogenic activities. In theophylline-induced melanogenesis in B16 melanoma cells, GlcCer [d18:2(4E,8Z)/18:0], GlcCer [d18:2(4E,8Z)/20:0], and elasticamide significantly suppressed melanin production with IC50 values of 6.6, 5.2, and 3.9 µM, respectively. Elasticamide, but not GlcCer [d18:2 (4E,8Z)/20:0], suppressed melanogenesis in human 3D-cultured melanocytes and the expression of tyrosinase-related protein 1 in normal human melanocytes. Based on these results, we conducted a clinical trial on the effects of rice ceramide extract (Oryza ceramide®), containing 1.2 mg/day of GlcCer and 56 µg/day of elasticamide, on UV-B-induced skin pigmentation. The ingestion of Oryza ceramide® for 8 weeks significantly suppressed the accumulation of melanin 7 days after UV irradiation (1288 and 1546 mJ/cm2 ·S). Rice-derived GlcCer and elasticamide, which exhibited anti-melanogenic activities, were suggested to contribute to the suppressive effects of Oryza ceramide® on UV-induced skin pigmentation. Although the mechanisms underlying the anti-melanogenic activities of GlcCer remain unclear, elasticamide was identified as a promising Cer that exhibits anti-melanogenic activity. PRACTICAL APPLICATIONS: The anti-melanogenic activities of rice-derived GlcCer and elasticamide currently remain unclear. We herein demonstrated the inhibitory effects of individual GlcCer and elasticamide on melanogenesis in melanoma cells, melanocytes, and human skin.

Undescribed glucosylceramide, flavonol triglycoside, and oleanane saponin from the halophyte Agathophora alopecuroides: Promising candidates for stimulating ceramide synthesis.

The phytochemical study of Agathophora alopecuroides (Chenopodiaceae) led to the isolation of previously undescribed glucosylceramide, flavonol triglycoside, and triterpene oleanane saponin, together with eight known compounds. Their structures were elucidated using NMR analysis and HR-MS as (2'R, 12E) N-[(2S, 3S, 4R)-1-(ß-D-glucopyranosyloxy)-3,4-dihydroxy-octadec-2-yl]-2-hydroxytetracos-12-enamide, namely Agathophamide A; isorhamnetin-3-O-[ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-ß-D-galactopyranoside, namely Agathophoroside A; and 3-O-[4'-(ß-D-xylopyranosyl)-ß-D-glucuronopyranosyl]-28-O-ß-D-glucopyranosyl-olean-12-en-3ß-ol-28-oic acid, namely Solysaponin A. We evaluated the effect of extract and isolates on ceramide levels via the up-regulated expression of the enzyme for ceramide synthesis in HaCaT keratinocytes. Interestingly, the study results revealed that the methanol extract of A. alopecuroides, together with some isolated compounds significantly up-regulated the mRNA expression of ceramide synthase-3 by 1.2- to 4.3-fold compared with the control in HaCaT cells. These findings indicate that the halophyte A. alopecuroides is a promising source of candidate compounds that can contribute to ceramide synthesis via the up-regulated expression levels of ceramide synthase-3 in the ceramide synthesis pathway.

Direct targeting of wild-type glucocerebrosidase by antipsychotic quetiapine improves pathogenic phenotypes in Parkinson's disease models.

Current treatments for Parkinson's disease (PD) provide only symptomatic relief, with no disease-modifying therapies identified to date. Repurposing FDA-approved drugs to treat PD could significantly shorten the time needed for and reduce the costs of drug development compared with conventional approaches. We developed an efficient strategy to screen for modulators of ß-glucocerebrosidase (GCase), a lysosomal enzyme that exhibits decreased activity in patients with PD, leading to accumulation of the substrate glucosylceramide and oxidized dopamine and α-synuclein, which contribute to PD pathogenesis. Using a GCase fluorescent probe and affinity-based fluorescence polarization assay, we screened 1280 structurally diverse, bioactive, and cell-permeable FDA-approved drugs and found that the antipsychotic quetiapine bound GCase with high affinity. Moreover, quetiapine treatment of induced pluripotent stem cell-derived (iPSC-derived) dopaminergic neurons from patients carrying mutations in GBA1 or LRRK2 led to increased wild-type GCase protein levels and activity and partially lowered accumulation of oxidized dopamine, glucosylceramide, and α-synuclein. Similarly, quetiapine led to activation of wild-type GCase and reduction of α-synuclein in a GBA mutant mouse model (Gba1D409V/+ mice). Together, these results suggest that repurposing quetiapine as a modulator of GCase may be beneficial for patients with PD exhibiting decreased GCase activity.

Anti-allergic property of 4,8-sphingadienine stereoisomers in vivo and in vitro model.

4,8-Sphingadienines (SD), metabolites of glucosylceramides (GlcCer), are sometimes determined as key mediators of the biological activity of dietary GlcCer, and cis/trans geometries of 4,8-SD have been reported to affect its activity. Since regulating excessive activation of mast cells seems an important way to ameliorate allergic diseases, this study was focused on cis/trans stereoisomeric-dependent inhibitory effects of 4,8-SD on mast cell activation. Degranulation of RBL-2H3 was inhibited by treatment of 4-cis-8-trans- and 4-cis-8-cis-SD, and their intradermal administrations ameliorated ear edema in passive cutaneous anaphylaxis reaction, but 4-trans-8-trans- and 4-trans-8-cis-SD did not. Although the activation of mast cells depends on the bound IgE contents, those stereoisomers did not affect IgE contents on RBL-2H3 cells after the sensitization of anti-TNP IgE. These results indicated that 4-cis-8-trans- and 4-cis-8-cis-SD directly inhibit the activation of mast cells. In conclusion, it was assumed that 4,8-SD stereoisomers with cis double bond at C4-position shows anti-allergic activity by inhibiting downstream pathway after activation by the binding of IgE to mast cells.

Protective Mechanism of Rice-Derived Lipids and Glucosylceramide in an In Vitro Intestinal Tract Model.

We previously reported that the ethanol extract from polished rice suppresses inflammation and the formation of aberrant crypt foci in the mouse colon and particularly focused on the plant sphingolipid glucosylceramide (GlcCer). Here, we investigated the effects of rice lipid fractions and GlcCer on differentiated Caco-2 cells treated with lipopolysaccharide (LPS), in particular, we evaluated the mechanism of action of GlcCer using related substances and metabolic enzyme inhibitors. Rice-derived polar lipids suppressed the LPS-induced reduction in the number of cells. The polar lipids with higher GlcCer content exerted a better effect than the other fractions. GlcCer-related substances reversed the LPS-induced reduction in the number of cells, and GlcCer-metabolic inhibitors, including a sphingosine kinase inhibitor, suppressed the beneficial effects of GlcCer-related substances. These results suggest that GlcCer is a rice component with intestinal protection. Secondly, GlcCer is metabolized during inflammation and protects intestinal cells by maintaining the sphingolipid levels in cells and producing sphingoid base-1-phosphate.

Dietary Ceramide Prepared from Soy Sauce Lees Improves Skin Barrier Function in Hairless Mice.

Dietary sphingolipids such as glucosylceramide and sphingomyelin are known to improve the skin barrier function of damaged skin. In this study, we focused on free-ceramide prepared from soy sauce lees, which is a byproduct of soy sauce production. The effects of dietary soy sauce lees ceramide on the skin of normal mice were evaluated and compared with those of dietary maize glucosylceramide. We found that transepidermal water loss value was significantly suppressed by dietary supplementation with soy sauce lees ceramide as effectively as or more effectively than maize glucosylceramide. Although the content of total and each subclass of ceramide in the epidermis was not significantly altered by dietary sphingolipids, that of 12 types of ceramide molecules, which were not present in dietary sources, was significantly increased upon ingestion of maize glucosylceramide and showed a tendency to increase with soy sauce lees ceramide intake. In addition, the mRNA expression of ceramide synthase 4 and involucrin in the skin was downregulated by sphingolipids. This study, for the first time, demonstrated that dietary soy sauce lees ceramide enhances skin barrier function in normal hairless mice, although further studies are needed to clarify the molecular mechanism.

Dietary Supplementation with Exogenous Sea-Cucumber-Derived Ceramides and Glucosylceramides Alleviates Insulin Resistance in High-Fructose-Diet-Fed Rats by Upregulating the IRS/PI3K/Akt Signaling Pathway.

Endogenous ceramide is considered to be associated with the progress of insulin resistance. However, the effects of dietary exogenous glucosylceramides and ceramides on insulin resistance are unclear. A model of fructose-induced male Sprague Dawley rats was used to compare the effects of sea-cucumber-derived glucosylceramides and ceramides on insulin resistance. Both glucosylceramides and ceramides significantly improved glucose tolerance, reduced the concentrations of serum glucose and glycosylated hemoglobin, and alleviated the accompanied hypertension. Ceramides significantly enhanced glycogen levels in skeletal muscle, whereas glucosylceramides significantly increased the hepatic glycogen levels. Moreover, glucosylceramides alleviated insulin resistance by inhibiting gluconeogenesis, promoting glycogen synthesis and insulin signal transduction in the liver; meanwhile, ceramides were mainly due to the promotion of glycogen synthesis and insulin signal transduction in skeletal muscle. Additionally, glucosylceramides and ceramides effectively attenuated inflammation in adipose tissue. These results indicate that glucosylceramides and ceramides have potential value in the prevention and alleviation of insulin resistance.

Effects of Dietary Ethanol Extracts from Sake Rice and Sake Lees on Intestinal Impairment in Mice.

Glucosylceramide (GlcCer), a major sphingolipid in plants and fungi, is known to have food functions, such as preventing intestinal impairment and enhancing the moisture content of skin. This study investigated the influence of fermentation on the composition and function of lipophilic components containing GlcCer in plant-based foods; we compared the effects of ethanol extracts from sake rice (SR) and sake lees (SL) on colon impairment in mice. GlcCer and ceramide (Cer) levels in SL were much higher than those in SR, and GlcCer in SL contained 9-methyl-trans-4,trans-8-sphingadienine as a fungi-specific sphingoid base. 1,2-dimethylhydrazine (DMH) treatment markedly increased the formation of aberrant crypt foci (ACF) and the levels of TNF-α and lipid oxidation in mice colons. However, dietary SR or SL significantly suppressed these DMH-induced changes, and SR demonstrated stronger effects than SL. In addition, dietary SR or SL suppressed the expression of apoptotic and anti-apoptotic proteins induced by DMH treatment. This study suggests that SR or SL intake could reduce colon ACF formation via the suppression of inflammation and oxidation-induced cell cycle disturbances. When compared to SR, the weaked effects of SL rich in GlcCer may be the result of the changes in sphingolipid composition (sphingoid base and Cer) and differences in the concentration of other bioactive compounds produced or digested during fermentation.

Polar Lipid Fraction from Golden Oyster Mushrooms (Pleurotus citrinopileatus) Suppresses Colon Injuries from Inflammatory Stresses in vivo and in vitro.

The rising incidence of inflammatory bowel disease (IBD) in East Asian countries has necessitated the implementation of preventive methods in the form of dietary supplementation and changes in dietary habits. We have previously reported that dietary golden oyster mushroom (Pleurotus citrinopileatus) ethanol extract (GOMEE) suppresses intestinal inflammation in mouse models of IBD induced by dextran sulfate sodium salt (DSS). Here, we investigated the components of GOMEE that exert suppressive effects on colon inflammation in vivo and in vitro. The total lipid fraction was extracted from GOMEE, and the polar and neutral lipid fractions were subsequently separated via solvent fractionation. Mice were assigned to dietary groups-control, 1% total lipid, 1% polar lipid, or 1% neutral lipid diet-and fed the respective diets for one week; mice were administered 1.5% DSS in drinking water ad libitum for 20 days. Dietary supplementation with the total or polar lipid fraction alleviated DSS-induced chorionic crypt injury as determined by morphological observation, while dietary supplementation with the neutral lipid fraction did not produce such effects. In the in vitro study, using differentiated Caco-2 cells as the colon model, treatment with the total or polar lipid fraction suppressed cell decrease by lipopolysaccharide (LPS)-induced apoptosis whereas treatment with the neutral lipid fraction did not. Moreover, accumulation of glucosylceramide (GlcCer), a fungal sphingolipid, was observed in the intestinal cells after treatment with polar lipid fraction. These results suggest that the active components of GOMEE that suppress colon inflammation are polar lipids, especially GlcCer. The structure of mushroom GlcCer differs from that of the plant counterpart and is therefore expected to exert different food functions.

Does tamoxifen have a therapeutic role outside of breast cancer? A systematic review of the evidence.

INTRODUCTION: Tamoxifen is a widely used hormonal based therapy for breast cancer in the adjuvant and metastatic setting, prolonging overall and recurrence-free survival. There has been increasing interest in the potential for novel "off-target" effects of tamoxifen and its metabolite N-desmethyltamoxifen across a number of cancer types. We aim to review the current literature regarding the potential use of tamoxifen in other primary malignancies. METHOD: A qualitative systematic review was performed according to the PRISMA guidelines using pre-set search criteria across the PubMed, Cochrane and Scopus databases from 1985 to 2019. Additional results were generated from included papers references. RESULTS: A total of 324 papers were identified, of which 47 were included; a further 29 articles were obtained from additional referencing to give a total of 76 articles. Clinical trials have demonstrated benefits with the use of tamoxifen in isolation and combination, specifically in patients with advanced non-resectable malignancy, however results are not consistent across the literature. In vivo data consistently suggests that off target effects of tamoxifen are mediated through the ceramide pathway or through inhibition of protein kinase C (PKC). CONCLUSIONS: With increased focus upon the potential of repurposing drugs, tamoxifen may be a candidate for repurposing in the wider cancer setting. There is evidence to suggest that the ceramide or PKC pathway could act as a therapeutic target for tamoxifen or alternative chemotherapeutics and merits further investigation.

Plant sphingolipids promote extracellular vesicle release and alleviate amyloid-ß pathologies in a mouse model of Alzheimer's disease.

The accumulation of amyloid-ß protein (Aß) in brain is linked to the early pathogenesis of Alzheimer's disease (AD). We previously reported that neuron-derived exosomes promote Aß clearance in the brains of amyloid precursor protein transgenic mice and that exosome production is modulated by ceramide metabolism. Here, we demonstrate that plant ceramides derived from Amorphophallus konjac, as well as animal-derived ceramides, enhanced production of extracellular vesicles (EVs) in neuronal cultures. Oral administration of plant glucosylceramide (GlcCer) to APP overexpressing mice markedly reduced Aß levels and plaque burdens and improved cognition in a Y-maze learning task. Moreover, there were substantial increases in the neuronal marker NCAM-1, L1CAM, and Aß in EVs isolated from serum and brain tissues of the GlcCer-treated AD model mice. Our data showing that plant ceramides prevent Aß accumulation by promoting EVs-dependent Aß clearance in vitro and in vivo provide evidence for a protective role of plant ceramides in AD. Plant ceramides might thus be used as functional food materials to ameliorate AD pathology.

Chemical Properties and Nutritional Value of Plant-Origin Glucosylceramide.

Glucosylceramide (GlcCer), a representative sphingolipid in cell membranes of plants and fungi, is known to have certain benefits, such as prevention of intestinal impairment and improved skin moisturizing, when consumed. Recently, incidence rates of intestinal impairments have increased in East Asian countries due to changes of people's diet and life style. Therefore, the occurrence of these impairments needs to be prevented through dietary improvement and supplements containing GlcCer. The in vitro and in vivo effects of GlcCer on colon impairment were explored in our previous studies, with focus on sphingolipid structure. Conversely, plant cell membrane contents such as GlcCer are known to be difficult to extract due to the thick cell wall. Therefore, human and other mammals may not be able to utilize GlcCer when digesting food of plant origin. To confirm this hypothesis, we investigated the effects of polished rice and the extract on intestinal impairment. In addition, we discuss the intestinal function of GlcCer contained in polished rice and the relationship between GlcCer and other lipophilic functional components.

Impact of Oral Intake of Glucosylceramide Extracted from Pineapple on Xerostomia: A Double-Blind Randomized Cross-Over Trial.

Background: The aim of this double-blind randomized cross-over trial was to evaluate the effect of oral intake of glucosylceramide extracted from pineapple on oral moisture and xerostomia symptoms. Methods: Sixteen participants who had xerostomia symptoms were randomly allocated into two groups. One group received, as test samples, tablets containing glucosylceramide extracted from pineapple (GCP) followed by placebo tablets. The other group received the test samples in the reverse order. Participants were instructed to take tablets of the first test sample once a day (after breakfast) for two consecutive weeks. Then, after a washout period of four weeks, participants were instructed to take the other test sample for two consecutive weeks. The oral moisture level of the lingual mucosa, xerostomia symptoms, and the number of fungiform papillae was evaluated. Results: The oral moisture significantly increased, and the visual analog scale (VAS) of "How is the dryness of your mouth?" significantly improved after GCP tablets intake and not after placebo tablets intake. The number of fungiform papillae was not significantly different following the intake of GCP tablets or placebo tablets. Conclusion: Results suggested that oral intake of GCP may improve the moisture level and xerostomia symptoms.

Extraction of Lipophilic Fraction from Polished Rice Improves Its Ameliorative Effect on Intestinal Impairment.

Glucosylceramide (GlcCer), a major sphingolipid in plants and fungi, is known to have food functions such as preventing intestinal impairment and enhancing the moisture content of skin. However, there is little information about functions of GlcCer in food sources as most of the studies on GlcCer functions are done using purified GlcCer. This study was performed to investigate the effects of GlcCer contained in food on intestinal impairment; polished rice flour (RF) and this ethanol extract (RE) were used as sources of GlcCer, and these were evaluated by studying the formation of aberrant crypt foci (ACF) in 1,2-dimethylhydrazine (DMH)-treated mice, which is a model of colon cancer. Mice were fed with either a control diet, a RF diet where RF replaces cornstarch (150 g/kg), or a plus RE diet (0.5 g/kg; RE was extracted from the same amount of RF present in the RF diet). The amount of GlcCer was similar in both the RF and RE diets (3.0 and 2.7 mg/kg, respectively). DMH treatment induced the formation of ACF and the production of inflammation-related cytokines. Both dietary RF and RE suppressed ACF formation and RE, in particular, showed a significant suppressive effect. Dietary RE inhibited the production of almost all of the inflammation-related cytokines studied, while RF suppressed only a few of these cytokines. The present study suggests that the lipophilic fraction including GlcCer, present in polished rice has protective effects against intestinal impairment, but it requires extraction since digestion alone is not enough to elicit its complete protective action.

A chemical genetic screen reveals that iminosugar inhibitors of plant glucosylceramide synthase inhibit root growth in Arabidopsis and cereals.

Iminosugars are carbohydrate mimics that are useful as molecular probes to dissect metabolism in plants. To analyse the effects of iminosugar derivatives on germination and seedling growth, we screened a library of 390 N-substituted iminosugar analogues against Arabidopsis and the small cereal Eragrostis tef (Tef). The most potent compound identified in both systems, N-5-(adamantane-1-yl-ethoxy)pentyl- L-ido-deoxynojirimycin (L-ido-AEP-DNJ), inhibited root growth in agar plate assays by 92% and 96% in Arabidopsis and Tef respectively, at 10 µM concentration. Phenocopying the effect of L-ido-AEP-DNJ with the commercial inhibitor (PDMP) implicated glucosylceramide synthase as the target responsible for root growth inhibition. L-ido-AEP-DNJ was twenty-fold more potent than PDMP. Liquid chromatography-mass spectrometry (LC-MS) analysis of ceramide:glucosylceramide ratios in inhibitor-treated Arabidopsis seedlings showed a decrease in the relative quantity of the latter, confirming that glucosylceramide synthesis is perturbed in inhibitor-treated plants. Bioinformatic analysis of glucosylceramide synthase indicates gene conservation across higher plants. Previous T-DNA insertional inactivation of glucosylceramide synthase in Arabidopsis caused seedling lethality, indicating a role in growth and development. The compounds identified herein represent chemical alternatives that can overcome issues caused by genetic intervention. These inhibitors offer the potential to dissect the roles of glucosylceramides in polyploid crop species.

Effect of Torula Yeast (Candida utilis)-Derived Glucosylceramide on Skin Dryness and Other Skin Conditions in Winter.

Glucosylceramide (GlcCer) is present in foods such as barley, corn, and wheat flour. GlcCer derived from different foods has differences in its physiological effects, depending on the sphingoid backbone and constituent fatty acids. In this study, we investigated the moisturizing and skin conditioning effects of GlcCer derived from torula yeast (Candida utilis) in healthy human subjects. The participants were randomly distributed in a crossover, double-blind comparative manner. Seventeen volunteers were orally administered both 1.8 mg/d of GlcCer derived from torula yeast and a placebo for 4 wk. Before and after oral administration, transepidermal water loss (TEWL) was measured and the objective skin condition observation and a questionnaire on skin condition were conducted. The primary endpoint was TEWL; secondary endpoints included the objective and subjective skin conditions. The change in TEWL over the study period on the forearm was -0.97±0.48 and -1.26±0.46 g/m2•h in the placebo and GlcCer groups, respectively, with significantly lower (p=0.01) TEWL observed in the GlcCer group. Brown spots increased in the placebo group but significantly decreased in the GlcCer group (p=0.04). Although chapped skin worsened in the placebo group, it significantly improved in the GlcCer group (p=0.04). The use of torula yeast-derived GlcCer as a functional cosmeceutical food is a viable option to ameliorate skin conditions, including improvement in skin barrier function, reduction of brown spots, and fixation of chapped skin.

Augmentation of dietary glucosylceramide hydrolysis by the novel bacterium Glucerabacter canisensis NATH-2371T.

The purpose of this study was to evaluate the effects of intragastrical administration of Glucerabacter canisensis NATH-2371T on glucosylceramide (GluCer) digestion in mice. Although G. canisensis was unable to utilize starch and cellulose, coculture of G. canisensis with mouse fecal bacteria greatly increased GluCer hydrolysis in polysaccharide medium, indicating that G. canisensis grew in competition with other intestinal bacteria. Although most of the administered G. canisensis cells were detected in feces, some cells were present in the colorectum contents, which had GluCer-hydrolyzing activity. These results indicate that G. canisensis can viably transit through the mouse gut. Administration of G. canisensis to mice fed diets supplemented with GluCer or GluCer-containing foods significantly enhanced GluCer hydrolysis. Since G. canisensis did not show acute toxicity, it may be useful as a probiotic to augment GluCer hydrolysis in the large intestine. Abbreviations: GluCer: glucosylceramide; KPi: potassium phosphate buffer; C-M: chloroform-methanol.

Glucerabacter canisensis gen. nov., sp. nov., isolated from dog feces and its effect on the hydrolysis of plant glucosylceramide in the intestine of dogs.

A Gram-positive, obligately anaerobic, oval-rod shaped, non-spore-forming, and non-pigmented bacterium, designated strain NATH-2371T (= JCM31739T = DSM105698T), was isolated from dog feces. Comparative 16S rRNA gene sequence analysis revealed that strain NATH-2371T belongs to Clostridium cluster XIVa, and the closest strains were Coprococcus comes ATCC 27758T (94.8% 16S rRNA gene sequence similarity) and Clostridium nexile DSM 1787T (94.0%). Strain NATH-2371T produced acetate, formate, and ethanol from glucose. Predominant cellular fatty acids are C16:0 and C16:0 DMA. On the basis of the phenotypic and genotypic differences, strain NATH-2371T represents a novel species in a new genus of the family Lachnospiraceae, for which the name Glucerabacter canisensis gen. nov., sp. nov., is proposed. This strain was found to efficiently hydrolyze plant glucosylceramide (GluCer). The abundance of strain NATH-2371T in dog feces was higher in young dogs than in old dogs. Incubation of dog fecal bacteria showed that GluCer-hydrolyzing activity decreased with the age of dogs. The cell number of strain NATH-2371T in dog feces appeared to be correlated with GluCer hydrolysis. Thus, this bacterium is likely to play a major role in GluCer hydrolysis in the dog intestine.