The purpose of this study was to clarify the cell growth inhibitory mechanism of human breast cancer cells caused by selenium (Se) compounds. In the presence of 17β-estradiol (E2) at physiological concentrations, growth of estrogen receptor α (ERα)-positive T47D cells was markedly inhibited by 1 × 10-6 mol/L methylseleninic acid (MSA) with no Se related toxicity.Under conditions where cell growth was inhibited, MSA decreased ERα mRNA levels and subsequent protein levels; further decreasing expression of estrogen-responsive finger protein (Efp) which is a target gene product of ERα and promotes G2/M progression of the cell cycle. Therefore, the decline in Efp expression is presumed to be involved in G2 arrest. Coincidentally, the antioxidative thioredoxin/ thioredoxin reductase (Trx/TrxR) system in cells was enhanced by the synergistic action of E2 and MSA. It has been reported that ROS-induced oxidative stress enhanced ERα expression. E2 increased production of intracellular ROS in T47D cells. Meanwhile, MSA significantly decreased E2-induced ROS accumulation. From these results, activation of the Trx/TrxR system induced by the coexistence of MSA and E2 suppresses oxidative stress and decreases expression of ERα, and finally induces the growth arrest of T47D cells through disruption of ERα signaling.
We studied the effect of acute stress on mouse immune system and found that the stress modified the proteins existing in the lymphocytes of liver. Performing SDS-polyacrylamide gel electrophoresis (SDS-PAGE), we got the result that the proteins existing in the lymphocytes were different between stressed liver and non-stressed liver, whereas we could not find any detectable differences in the lymphocyte proteins between stressed spleen and non-stressed spleen. In stressed liver lymphocytes, we found thirteen clear bands in the stained gel that were not prominent in non-stressed liver lymphocytes.
Glial cells missing Drosophila homolog a (GCMa) is a member of the GCM transcription factor family and plays critical roles in trophoblast differentiation and placental functions. It is well established that the cyclic AMP (cAMP)-dependent pathway induces the expression and transcriptional activity of GCMa by regulating post-translational modifications of GCMa, which results in enhancement of trophoblast differentiation. We previously observed that phorbol 12-myristate 13-acetate (PMA) stimulates phosphorylation of GCMa on serines 328, 378 and 383 through the protein kinase C (PKC)- and mitogen-activated protein kinase kinase (MEK)/extracellular signalregulated kinase (ERK)-dependent pathway, which decreases the protein stability of GCMa. Here we report that PMA increases the ubiquitination level of GCMa, dependent on the phosphorylation of GCMa on serines 328, 378 and 383. We found that this phosphorylation also stimulates the transcriptional activity of GCMa. Our data indicate that the PMA-induced PKC- and MEK/ERKdependent pathway enhances the degradation as well as the transcriptional activity of GCMa. We also examined the impact of this signaling pathway on trophoblasts and the results suggest that the PKC- and MEK/ERK-dependent pathway is involved in the regulation of trophoblast differentiation.
This study examined the immunoexpression pattern of aquaporin-1 (AQP1), first identified as a water channel protein, in the periodontal ligament of rat molars during experimental tooth movement to clarify its role in periodontal responses in an overloaded model by the insertion of a piece of elastic band. In the control group without any treatment, the cementoblasts and osteogenic cells as well as the vascular endothelial cells showed AQP1 immunoreaction. In the experimental group, hyalinized tissue and intensely AQP1 positive amorphous structures which were identified as degenerated endothelial cells by immunoelectron microscopy, occurred at the compression side on Days 1 and 3. AQP1 immunoreaction came to be stronger in the intact endothelial cells around the hyalinized tissue. The hyalinized tissue had almost disappeared by Day 5 when many macrophages reactive to acid phosphatase activity appeared. The periodontal width on Day 7 became almost the same as that in the control group. These findings indicate that the hyalinized tissue and damaged AQP1 positive endothelial cells are phagocytized by macrophages which have temporally migrated, and suggest that the surviving endothelial cells with intense AQP1 reaction are involved in periodontal regeneration by capillary sprouting.
Kale (Brassica oleracea L. var acephala DC) is a leafy green vegetable belonging to the cabbage family (Brassicaceae) that contains a large amount of health-promoting phytochemicals. There are any reports about the effects of kale ingestion on the chemoprevention function and mechanism, but the interactions between kale and drugs have not been researched. We investigated the effects of kale intake on cytochrome P450 (CYP) metabolism by using cocktail probe drugs, including midazolam (for CYP3A4), caffeine (for CYP1A2), dextromethorphan (for CYP2D6), tolbutamide (for CYP2C9), omeprazole (for CYP2C19), and chlorzoxazone (for CYP2E1). Cocktail drugs were administered into rats treated with kale and cabbage (2000 mg/kg) for a week. The results showed that kale intake induced a significant increase in plasma levels and the AUC of midazolam, caffeine, and dextromethorphan. In addition, the plasma concentration and AUC of omeprazole tended to increase. Additionally, no almost differences in the mRNA expression levels of CYP enzymes in the liver were observed. In conclusion, kale ingestion was considered to have an inhibitory effect on the activities of CYP3A4, 1A2, 2D6, and 2C19 for a reason competitive inhibition than inhibitory changes in the mRNA expressions.
Skin rubdown using a dry towel (SRDT) to scrub the whole body is a traditional therapy for health promotion. To investigate its mechanism, 24 healthy male volunteers were studied. Body temperature, pulse rate, red blood cells (RBCs), serum levels of catecholamines and cortisol, blood gases (PO2, sO2, PCO2 and pH), lactate and glucose, and the ratio and number of white blood cells (WBCs) were assessed before and after SRDT. After SRDT, pulse rate and body temperature were increased. PO2, sO2 and pH were also increased and there was no Rouleaux formation by RBCs. Lactate level tended to increase, whereas that of glucose did not. Adrenaline and noradrenaline levels increased, indicating sympathetic nerve (SN) dominance with increase in granulocytes. WBC number and ratio were divided into two groups according to granulocyte ratio (≤ or < 60%) before SRDT: a normal group and a SN group. Only in the SN group did the granulocyte ratio decrease and the lymphocyte ratio and number increase after SRDT. It is suggested that SRDT is a mild aerobic, systemic exercise that might affect the immune system via the autonomic nervous system.
The endothelin signaling pathway plays an important role in the migration, proliferation, and differentiation of neural crest cells. Mutations in the gene encoding the endothelin receptor type B (EDNRB) cause three symptoms: aganglionosis, pigmented disorder and hearing loss. In addition, the Ednrb null mice show abnormal splenic microarchitecture with lymphopenia. In this study, we examined whether similar phenotypes are reproduced in three Ednrb-null rat strains that we established previously. AGH-Ednrbsl/sl strain showed a low white blood cell count, significant size reduction and abnormal microarchitecture of spleen. Thymus displayed a marked reduction in the size, but maintained a normal CD4/CD8 ratio. In contrast, splenic cellularity was reduced to < 15%, and splenic B and T cell numbers were reduced, showing a splenic lymphopenia. Interestingly, Ednrb-null rats in the LE and F344 genetic background did not show these abnormalities. These data show that proper T and B cell development is dependent on the endothelin signaling pathway, however, modifier gene(s) might be differentially expressed in these strain to modulate or compensate for the effect of the Ednrb deficiency.