Lysophosphatidylcholine (lysoPC) stimulates the release of prostaglandins (PGs) in various cells and tissues. Cyclooxygenase (COX)-2 has recently emerged as a key regulator of PG synthesis. We investigated whether lysoPC regulates COX-2 expression in cultured rat vascular smooth muscle cells (VSMCs). LysoPC strongly increased the expression of COX-2 mRNA in a time- and dose-dependent manner. COX-2 protein expression also was increased by lysoPC. The p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 significantly suppressed lysoPC-induced COX-2 mRNA and protein expression, but not a p42/44MAPK kinase (MEK-1) inhibitor, PD98059. LysoPC did not increased the transcription of the COX-2 gene, as assayed with a COX-2 promoter/luciferase chimeric plasmid and suppressed the decay of COX-2 mRNA. SB203580 markedly enhanced the decay of COX-2 mRNA induced by lysoPC, implying that p38MAPK activated by lysoPC helps to regulate COX-2 by stabilizing its mRNA. The COX-2 specific inhibitor NS-398 attenuated lysoPC-stimulated DNA and protein synthesis as well as PGE2 production by VSMCs. These results suggest that in rat VSMCs lysoPC regulates COX-2 expression and PG production and also modulates cell proliferation through p38MAPK-mediated signaling pathways.
H. pylori is a gram-negative bacterium associated with gastric inflammation and peptic ulcer and considered a risk factor for gastric cancer in its natural habitat. However, the energy metabolism of H. pylori in the stomach remains to be clarified. H. pylori shows rather high respiratory activity with L-proline and significantly large amounts of L-proline are present in the gastric juice from H. pylori infected patients. We constructed a disrupted mutant of the put A gene, which encodes the proline utilization A (Put A) flavin-linked enzyme, in order to examine the role of put A in the gastric colonization of H. pylori. The put A disrupted mutant, ΔputA, was constructed by inserting a chloramphenicol resistant gene into put A. ΔputA did not show respiratory activity using L-proline and could not incorporate L-proline into cells. ΔputA also did not show motility in response to amino acids and did not display the swarming activity observed with the wild-type. ΔputA had lost its ability to colonize the stomach of nude mice, an ability possessed by the wild-type. These findings indicate that put A may play an important role in H. pylori colonization on the gastric mucus layer.
Immunosuppressive cytokine, interleukin 10 (IL-10), is associated with progression of the renal cell carcinoma (RCC). However, the roles of its cell surface receptor, interleukin 10 receptor (IL-10R), remain elusive. We quantified IL-10R mRNA expression in paired tumor and non-tumor samples from the surgical specimens of 71 consecutive patients with RCC using a real-time reverse transcription polymerase chain reaction (RT-PCR). The absolute level of IL-10R mRNAs in tumor and non-tumor tissues did not correlate with the malignant and metastatic profiles. The relative yields of the PCR product from the tumor tissue to that from the corresponding non-tumor tissue (T/N) for the expression of IL-10R mRNAs were calculated. A high T/N ratio of IL-10R correlated with poor differentiation (P < 0.001) and metastasis (P < 0.0001). By univariate analysis, a high T/N ratio of IL-10R predicted a shortened overall survival in all cases (P < 0.01). These findings suggest that IL-10R is associated with the progression of RCC.
Although it is known that tea catechins exert potent effects in obese subjects, there is scant information concerning these effects on body weight gain and body fat accumulation in the non-obese. We studied normal rats fed a normal diet and water containing either 0.1% or 0.5% tea catechins to examine the effects on body fat content and serum cholesterol levels, as well as evaluating whether the effect is related to bile acids, which in recent years have emerged as an inducer of energy expenditure. The administration of 0.5% catechins decreased the accumulation of body fat and the serum levels of cholesterol and bile acids. These results indicate that tea catechins modulate lipid metabolism not only in obese subjects, but also in the non-obese.
The calcitonin-gene related peptide (CGRP) is a primary afferent neurotransmitter in the trigeminal system. Although a neonatal administration of capsaicin eliminates substance P (SP)-mediated nociceptive responses to induce a permanent functional reduction in C-fibers, little information is available regarding changes in CGRP-immunoreaction in mice undergoing neonatal capsaicin treatment (CP mice). This study examined postnatal changes in the distribution of CGRP-immunoreaction in the trigeminal subnucleus caudalis and trigeminal ganglion of CP mice by immunohistochemical technique and a quantitative analysis. Immunohistochemistry for CGRP in the subnucleus caudalis (Vc) demonstrated two dense distributions of neurons in the CP mice as well as naïve mice: in the marginal layer and the region 400-600 μm deep. The quantitative analysis revealed no significant difference in the density of CGRP immunoreaction between naïve and CP mice 1-8 weeks of age. In the trigeminal ganglion of both groups, the size distribution of CGRPpositive neurons displayed a distribution pattern with one peak in 200-300 μm2 at week 1 and with two peaks in 200-300 μm2 and 600-700 μm2 at week 8 but no significant difference in neural density existed between these regions. When double staining in the naïve mice with CGRP or SP and VR1, a capsaicin receptor, was done, many trigeminal ganglion neurons co-expressed SP- and VR1-immunoreactions, but rarely exhibited CGRP/VR1-co-localization. Taken together with previous data, these current observations suggest that CGRP containing afferent neurons possibly performs differing roles in nociceptive afferent input transmission within the Vc from SP-containing neurons in mice.
Using a representative table game popular in Japan known as shogi, or Japanese chess, we investigated the effects of winning and losing on saliva composition. The subjects were 90 healthy male university students who were members of a shogi club. Saliva samples were collected immediately before and after playing shogi, and again 30 min later. Salivary cortisol and testosterone levels in the samples were determined by ELISA and EIA, respectively. After finishing each game, the competitiveness of the game was evaluated using questionnaires. In the samples taken after playing shogi, there was an increase in the levels of salivary testosterone and cortisol, regardless of whether the subject won or lost, and the tendency was more pronounced in competitive games. There were no such changes in the control group, who did not play a game prior to providing the samples. Our results suggest that stress response is intimately linked with competition and could be used to determine which players are more capable of handing stress in a competitive environment.
Because chondrosarcoma is resistant to chemotherapy and ionizing radiation, the primary treatment of chondrosarcoma is surgical resection. Effective chemotherapeutic agents for chondrosarcoma are necessary. Although there is evidence that CD44 is involved in apoptosis susceptibility in several cell types, the effectiveness of anti-CD44 treatment on chondrosarcoma has never been studied. This study was aimed to clarify whether anti-CD44 monoclonal antibody induces apoptosis in human chondrosarcoma cell line SW1353. Confocal microscopy revealed that the SW1353 cells expressed CD44 that bound the anti-CD44 antibody IM7. Treatment of the cells with IM7 resulted in a significant decrease in cell viability, compared with that with control IgG. In contrast, IM7 failed to reduce cell viability in human chondrocytes. In SW1353 cells, IM7 induced chromatin condensation, nuclear fragmentation, and apoptotic body formation while control IgG had marginal effect. These data indicate that anti-CD44 treatment could induce apoptosis in chondrosarcoma cells.
Pirh2 is a RING finger type ubiquitin ligase which ubiquitylates various proteins including p53, p27Kip1, HDAC1, and ε-COP. In this study, we identified signal recognition particle receptor β subunit (SRβ), an integral membrane protein of the endoplasmic reticulum (ER), as a novel Pirh2-interacting protein by yeast two-hybrid screening. We confirmed that Pirh2 interacted with SRβ in mammalian cells. An immunofluorescent staining revealed that Pirh2 colocalized with SRβ in the ER. Pirh2 poly-ubiquitylated SRβ in an intact RING finger domain-dependent manner in vivo and in vitro. Unexpectedly, different from other Pirh2 substrates, neither overexpression of Pirh2 nor depletion of cellular Pirh2 affected SRβ protein stability. Pirh2 preferentially utilized lysine residues 6 and 29 of the ubiquitin to mediate the formation of polyubiquitin chains on SRβ. These results suggest that Pirh2 may regulate SRβ function by mediating poly-ubiquitylation of SRβ without affecting the stability of SRβ protein per se.