Cytotoxic labdane alkaloids from an ascidian Lissoclinum sp.: isolation, structure elucidation, and structure-activity relationship

Four labdane alkaloids, haterumaimides N-Q (1-4), were isolated from an ascidian Lissoclinum sp. and their structures were elucidated by chemical and spectral analyses. Investigation of the structure-activity relationships of haterumaimides J-K, N-Q, and 14 related compounds suggested that the presence of hydroxyl groups at C-6, C-7, C-12, and C-18, a chlorine atom at C-2, and an imido NH in ring C should be essential for cytotoxicity against P388 cells.     

Identification of a royal jelly glycoprotein that carries unique complex-type N-glycans harboring the T-antigen (Galβ1-3GalNAc) unit

In this study, we identified a royal jelly glycoprotein (RJG) that carries a unique complex-type N-glycans harboring the T-antigen (Galβ1-3GalNAc) unit. The amino acid sequence of the tryptic glycopeptide harboring the T-antigen unit was G-E-S-L-X-K (X might be glycosylated Asn), confirmed in the major royal jelly glycoprotein 1 (MRJP1), which is also expressed in the mushroom body of the honeybee brain.     

In vitro ectomycorrhizal specificity between the Asian red pine Pinus densiflora and Tricholoma matsutake and allied species from worldwide Pinaceae and Fagaceae forests

Tricholoma matsutake produces commercially valuable, yet uncultivable, mushrooms (matsutake) in association with pines in the Far East and Scandinavia and with both pines and oaks in the foothills of Tibet. Other matsutake mushrooms, such as Tricholoma anatolicum from the Mediterranean regions and Tricholoma magnivelare and Tricholoma sp. from the North Pacific Coast area of Canada and North America as well as Mexico, respectively, are associated with pines or oaks in their natural habitats. Tricholoma bakamatsutake and Tricholoma fulvocastaneum from Asia produce moderately valuable matsutake mushrooms and are solely associated with Fagaceae in nature. In this study, we demonstrate for the first time that matsutake mushrooms from Scandinavia, Mediterranean regions, North America, and Tibet form ectomycorrhizae with Pinus densiflora similar to the Far East T. matsutake. In general, worldwide T. matsutake and the symbionts of Pinaceae colonize the rhizospheres of P. densiflora as well as T. matsutake isolated from the host plant. However, T. fulvocastaneum and T. bakamatsutake formed a discontinuous Hartig net and no Hartig net, respectively, and colonized to a lesser extent as compared to T. matsutake. The data suggest that conifer-associated matsutake mushrooms in their native habitat will associate symbiotically with the Asian red pine.     

The receptor-like kinase KLAVIER mediates systemic regulation of nodulation and non-symbiotic shoot development in Lotus japonicus

In legumes, the number of symbiotic root nodules is controlled by long-distance communication between the shoot and the root. Mutants defective in this feedback mechanism exhibit a hypernodulating phenotype. Here, we report the identification of a novel leucine-rich repeat receptor-like kinase (LRR-RLK), KLAVIER (KLV), which mediates the systemic negative regulation of nodulation in Lotus japonicus. In leaf, KLV is predominantly expressed in the vascular tissues, as with another LRR-RLK gene, HAR1, which also regulates nodule number. A double-mutant analysis indicated that KLV and HAR1 function in the same genetic pathway that governs the negative regulation of nodulation. LjCLE-RS1 and LjCLE-RS2 represent potential root-derived mobile signals for the HAR1-mediated systemic regulation of nodulation. Overexpression of LjCLE-RS1 or LjCLE-RS2 did not suppress the hypernodulation phenotype of the klv mutant, indicating that KLV is required and acts downstream of LjCLE-RS1 and LjCLE-RS2. In addition to the role of KLV in symbiosis, complementation tests and expression analyses indicated that KLV plays multiple roles in shoot development, including maintenance of shoot apical meristem, vascular continuity, shoot growth and promotion of flowering. Biochemical analyses using transient expression in Nicotiana benthamiana revealed that KLV has the ability to interact with HAR1 and with itself. Together, these results suggest that the potential KLV-HAR1 receptor complex regulates symbiotic nodule development and that KLV is also a key component in other signal transduction pathways that mediate non-symbiotic shoot development.     

Inhibition of N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase by ß-D-4-O-sulfo-N-acetylgalactosaminides bearing various hydrophobic aglycons

N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase (GalNAc4S-6ST) transfers sulfate to position 6 of GalNAc(4SO₄) residues of chondroitin sulfate to yield chondroitin sulfate E (CS-E). We have previously demonstrated that phenyl-ß-D-GalNAc(4SO₄) could serve as an acceptor for GalNAc4S-6ST, thereby inhibiting GalNAc4S-6ST competitively. In this paper we compared the inhibitory effects of various glycosides in which various hydrophobic aglycons were attached to D-GalNAc(4SO₄) via ß anomeric configuration. p-Nitrophenyl-ß-D-GalNAc(4SO₄) and p-chlorophenyl-ß-D-GalNAc(4SO₄) were stronger inhibitors than phenyl-ß-D-GalNAc(4SO₄). Among inhibitors examined here, 3-estradiol-ß-D-GalNAc(4SO₄) was the strongest inhibitor; the Ki of 3-estradiol-ß-D-GalNAc(4SO₄) for the competitive inhibition was 0.008 mM, which was much lower than the Ki of phenyl-ß-D-GalNAc(4SO₄), 0.98 mM. In contrast, 7-estradiol-ß-D-GalNAc(4SO₄) showed only weak inhibition to GalNAc4S-6ST. 3-Estradiol- ß-D-GalNAc(4SO₄) did not inhibit chondroitin 6-sulfotransferase and chondroitin 4-sulfotransferase under the concentration where GalNAc4S-6ST was inhibited by 90%. When 3-estradiol- ß-D-GalNAc(4SO₄) was added to the culture medium of chondrosarcoma cells expressing human GalNAc4S-6ST, a significant, albeit small, reduction in the cellular synthesis of CS-E was observed. These results suggest that estradiol group of 3-estradiol-ß-D-GalNAc(4SO₄) may enhance the inhibitory activity of the glycoside through increasing the affinity to the enzyme and may allow the glycosides to diffuse at a low efficiency into the cells to inhibit cellular synthesis of CS-E.     

Prognostic value of CD208-positive cell infiltration in gastric cancer

Background and aim

A new marker, CD208, was recently explored as a mature interdigitating dendritic cell (DC), and the correlation between the infiltration of CD208-positive cells and clinical factors has been reported in various types of cancers. In this study, we tried to clarify the clinical implication of CD208-positive cell infiltration in gastric cancer immunohistochemically.

Patients and methods

A total of 128 gastric cancer patients who underwent a curative operation were enrolled. DCs in tumor nests were identified with two DC markers, CD208 and S-100 protein (S100), by immunohistochemistry. The correlation between clinicopathological features and the CD208- or S100-positive cell infiltration degree was analyzed.

Results

Infiltration of S100-positive cells did not correlate with the degree of CD208-positive cell infiltration. Patients with high CD208-positive cell infiltration in the peritumor had a poorer surgical outcome than those with low CD208 infiltration (p < 0.05). Multivariate analysis revealed that CD208-positive cell infiltration was not an independent prognostic factor.

Conclusion

We showed that intratumoral CD208-positive cells, as mature DCs, had an inverse correlation to patients’ postoperative outcome in gastric cancer, unlike a conventional DC marker. Evaluation of CD208-positive cell infiltration with S100-positive cell infiltration in gastric cancer is useful to predict antitumor immunological conditions in gastric cancer.     

Female exhibited severe cognitive impairment in type 2 diabetes mellitus mice

AimsSex-specific medicine has been highlighted as a different approach to the diagnosis and treatment of diseases between men and women. Type 2 diabetes has been reported to be a risk factor for cognitive impairment. Here, we investigated the sex difference in cognitive function associated with diabetes using KKAy mice.Main methodsCognitive function was evaluated by shuttle avoidance test and Morris water maze test. Changes in gene expression in the brain were evaluated by PCR array and confirmed by quantitative RT-PCR. To evaluate the effect of estradiol, some female KKAy were ovariectomized and treated with or without estradiol.Key findingsIn KKAy mice, female significantly exhibited impaired cognitive function compared with male, while there was no sex difference in these cognitive functions in C57BL6, wild-type mice. Female KKAy mice showed hyperinsulinemia, impaired glucose tolerance and increased oxidative stress compared with male KKAy mice. Female KKAy also showed a significant decrease in peroxisome proliferators-activated receptor (PPAR)-γ expression in the brain compared with male KKAy. Estradiol treatment improved the insulin resistance and higher superoxide production, but failed to improve the cognitive task performance, serum insulin level and lower expression of PPAR-γ.SignificanceIn diabetic mice, female showed significantly impaired cognitive function, with greater insulin resistance, lower expression of PPAR-γ and higher superoxide production compared with male. Estrogen had little effect on cognitive function. These results indicate that a sex-specific approach to cognitive impairment is necessary for diabetic patients, especially for women.     

Dosing-time dependent effect of dexamethasone on bone density in rats

AimsWhile glucocorticoids are widely used to treat patients with various diseases, they often cause adverse effects such as bone fractures. In this study, we investigated whether the decrease in bone density induced by glucocorticoid therapy was ameliorated by optimizing a dosing-time.Main methodsRats were administered with dexamethasone (Dex) orally (1 mg/kg/day) for 6 weeks at a resting or an active period. After the end of the treatment, bone density of femur, biomarkers of bone formation and resorption, and other biomedical variables were measured.Key findingsBone density of femur was significantly decreased by the 6-week treatment with Dex, and the degree of decrease in the 14 HALO (hours after light on) dosing group (an active period) was larger than that in the 2 HALO dosing group (a resting period). Although urinary calcium excretion was accelerated by Dex treatment, secondary hyperparathyroidism was not detected. Histomorphometry analysis showed that Dex suppressed bone resorption, which was larger in the 2 HALO than in the 14 HALO groups. These data indicate that Dex equally suppressed bone formation in the 2 and 14 HALO groups, but inhibited bone resorption more in the 2 HALO than in the 14 HALO groups.SignificanceThis study shows that the decrease in bone density induced by Dex was changed by its dosing-time.