Amino acid homeostatic control by TORC1 in Saccharomyces cerevisiae under high hydrostatic pressure.

Mechanical stresses, including high hydrostatic pressure, elicit diverse physiological effects on organisms. Gtr1, Gtr2, Ego1 (also known as Meh1) and Ego3 (also known as Slm4), central regulators of the TOR complex 1 (TORC1) nutrient signaling pathway, are required for the growth of Saccharomyces cerevisiae cells under high pressure. Here, we showed that a pressure of 25 MPa (∼250 kg/cm2) stimulates TORC1 to promote phosphorylation of Sch9, which depends on the EGO complex (EGOC) and Pib2. Incubation of cells at this pressure aberrantly increased glutamine and alanine levels in the ego1Δ, gtr1Δ, tor1Δ and pib2Δ mutants, whereas the polysome profiles were unaffected. Moreover, we found that glutamine levels were reduced by combined deletions of EGO1, GTR1, TOR1 and PIB2 with GLN3 These results suggest that high pressure leads to the intracellular accumulation of amino acids. Subsequently, Pib2 loaded with glutamine stimulates the EGOC-TORC1 complex to inactivate Gln3, downregulating glutamine synthesis. Our findings illustrate the regulatory circuit that maintains intracellular amino acid homeostasis and suggest critical roles for the EGOC-TORC1 and Pib2-TORC1 complexes in the growth of yeast under high hydrostatic pressure.

Effects of Sodium-Glucose Cotransporter 2 Inhibition on Glucose Metabolism, Liver Function, Ascites, and Hemodynamics in a Mouse Model of Nonalcoholic Steatohepatitis and Type 2 Diabetes.

Many blood glucose-lowering drugs cannot be used once patients with type 2 diabetes (T2D) and nonalcoholic fatty liver disease develop nonalcoholic steatohepatitis (NASH). Therefore, such patients often require insulin treatment. We aimed to determine the effect of sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin monotherapy on glucose metabolism in a mouse model of NASH/T2D, with a focus on its diuretic effects. To imitate ascites and to determine its severity by imaging, meglumine sodium amidotrizoate (MSA) was infused into the abdominal cavities of mice. The reduction in ascites induced by dapagliflozin was compared with that induced by furosemide using microcomputed tomography. The effects of each drug on hemodynamics were also compared. A dapagliflozin-related improvement in glucose tolerance was achieved in mice fed a high-fat diet (HFD) or an HFD + methionine-and-choline-deficient diet (MCDD). In dapagliflozin-treated NASH mice, hypoglycemia was not identified during 24-hour casual blood glucose monitoring. In the dapagliflozin and furosemide-treated groups, the time taken for the resolution of artificial ascites was significantly shorter than in the untreated group, and there were no significant differences between these groups. Furosemide significantly reduced the blood pressure and significantly increased the heart rate of the mice. Dapagliflozin caused a mild decrease in systolic, but not diastolic blood pressure, and the heart rate and circulating catecholamine and renin-aldosterone concentrations were unaffected. Dapagliflozin treatment improved glycemic control in the NASH mice versus untreated mice. Thus, dapagliflozin had a prompt diuretic effect but did not adversely affect the hemodynamics of mice with NASH and T2D. Therefore, it may be useful for the treatment of patients with both T2D and liver cirrhosis.

Reintroducing testosterone in the db/db mouse partially restores normal glucose metabolism and insulin resistance in a leptin-independent manner.

BACKGROUND: Testosterone signals through the androgen receptor (AR) and AR knockout mice develop obesity, suggesting a functional association between AR and leptin signaling. Furthermore, physiological blood concentrations of testosterone have been found to inhibit the development of arteriosclerosis, obesity and diabetes. However, these findings have not been verified by testosterone replacement in animal models and whether or not testosterone acts directly by activating AR to enhance leptin signaling, or indirectly by its conversion into estrogen remains unclear. Therefore, we investigated the effect of exogenously supplemented testosterone on glucose and lipid metabolism. METHODS: Four-week-old male leptin receptor-knockout db/db mice were used as controls for a model of obesity retaining low testosterone. Mice were divided into sham-operated, castrated, or castrated and testosterone-supplemented groups and fed a high-fat diet (HFD) for 2 weeks from 5 weeks of age. Testosterone concentrations, blood glucose, plasma insulin levels, and intraperitoneal glucose tolerance and insulin tolerance were measured. At 7 weeks, triglyceride and glycogen content were measured in the liver and muscle. Lipid accumulation in the liver and soleus muscle was determined by immunohistochemistry with Oil Red O. Statistical analyses were performed using the Student's t-test or ANOVA where applicable. RESULTS: Lower testosterone levels in db/db mice compared with wild type (WT) db/+ mice were associated with glucose intolerance and fatty liver. Furthermore, castrated male db/db mice at 4 weeks of age progressively developed glucose intolerance accompanying a 15% increase in liver fat. Male mice fed a HFD had lower levels of testosterone compared with those fed a normal diet. We found that exogenous testosterone replacement injected subcutaneously into castrated male db/db mice alleviated the exacerbation of fatty liver and glucose intolerance, suggesting a leptin-independent mechanism. This mechanism is most likely mediated through gonadal axis suppression in this mouse model. CONCLUSIONS: In summary, testosterone may use a novel pathway to complement leptin signaling to regulate glucose and lipid metabolism, and thus offers a new therapeutic target to treat metabolic disorders.

Role of thrombin-PAR1-PKCθ/δ axis in brain pericytes in thrombin-induced MMP-9 production and blood-brain barrier dysfunction in vitro.

Thrombin, an essential component in the coagulation cascade, participates in the pathogenesis of brain diseases, such as ischemic stroke, intracerebral hemorrhage, Alzheimer's disease and Parkinson's disease through blood-brain barrier (BBB) dysfunction. It is thought that the thrombin-matrix metalloproteinase (MMP)-9 axis is an important process in the pathogenesis of neurovascular disease, such as BBB dysfunction. We recently reported that brain pericytes are the most MMP-9-releasing cells in response to thrombin stimulation among the BBB-constituting cells. This thrombin-induced MMP-9 release is partially due to protease-activated receptor (PAR1), one of the specific thrombin receptors. Then, we evaluated the intracellular signaling pathways involved in MMP-9 release and the contribution of thrombin-reactive brain pericytes to BBB dysfunction. PKC activator evoked MMP-9 release from brain pericytes. The thrombin-induced MMP-9 release was inhibited by U0126, LY294002, Go6976, and Go6983. However, Go6976 decreased phosphorylation levels of PKCθ and Akt, and Go6983 decreased phosphorylation levels of PKCδ and extracellular signal-regulated kinase (ERK). Additionally, treatment of pericytes with thrombin or PAR1-activating peptide stimulated PKCδ/θ signaling. These substances impaired brain endothelial barrier function in the presence of brain pericytes. Brain pericytes function through two independent downstream signaling pathways via PAR1 activation to release MMP-9 in response to thrombin - the PKCθ-Akt pathway and the PKCδ-ERK1/2 pathway. These pathways participate in PAR1-mediated MMP-9 release from pericytes, which leads to BBB dysfunction. Brain pericytes and their specific signaling pathways could provide novel therapeutic targets for thrombin-induced neurovascular diseases.

[Perceptual and cognitive characteristics of metaphorical pain language].

This study investigated the perceptual and cognitive characteristics of metaphoric and onomatopoeic descriptions of physical pain. Ninety-eight Japanese pain descriptors were identified from previous pain studies and the World Wide Web. Four hundred and thirty-six Japanese undergraduates were asked to indicate for each descriptor: (a) body locations; (b) temporal (duration, interval repetition, and frequency), spatial (movement, depth, area, volume) and magnitude (strength) levels; and (c) ratings on seven semantic differential scales for cognitive evaluation. Correspondent analysis and principal component analysis indicated good correspondence between the perceptual and cognitive characteristics. Cluster analysis revealed that the 98 descriptors fall into eleven clusters that appear to be associated with different underlying metaphors for pain (e.g., the body as a container that experiences pain as the result of damage from an object or weapon). These results are discussed in terms of the relationship between the metaphors people use to describe their pain experience and the potential for bodily-basis conceptualization of pain.

A new Japanese vegetarian food guide.

Vegetarianism continues to gain popularity in Japan and the Westernized world, in part from decades of science supporting the health advantages of properly planned vegetarian-based diets. Although there are Asian nutritional tools, one specific to a Japanese vegetarian diet is lacking. Thus, the Japanese vegetarian food guide (JVFG) was developed and based in part on the American Dietetic Association position paper for vegetarian diets and the Japanese Food Guide Spinning Top. The JVFG was developed by collecting dietary information from 3 different institutes in Japan that specialize in regularly offering vegetarian meals. The JVFG was divided into 6 groups with respective recommended servings: vegetables (7.5), grains (4.5), protein foods (4), milk (3), fruits (2), and fats, sugar, and seasonings (<3). The JVFG was developed so that it would adequately provide for all nutrients and be structured for practical use by the general public as well as health professionals.

Nutritional characteristics of middle-aged Japanese vegetarians.

AIM: Despite the possible overall health benefits of a vegetarian diet, research about the nutritional characteristics of Japanese vegetarians is small. Our objective was to investigate the nutritional characteristics of Japanese vegetarians compared with Japanese non-vegetarians. METHODS: The dietary intake, anthropometric and biochemical status of 75 middle-aged Japanese vegetarians (JV, 20 men and 55 women) were compared with those of 50 age- and sex- matched middle-aged Japanese non-vegetarians (JNV, 32 men and 18 women) in a cross-sectional study. RESULTS: JV men had significantly higher calcium, iron (p<0.001) and dietary fiber (p<0.01), and significantly lower vitamin B(12), cholesterol, animal fat intake and percentage of energy as animal protein (p<0.01) than JNV men. In addition, JV men had significantly lower body mass index (p<0.05), diastolic blood pressure (p<0.001), systolic blood pressure (p<0.01), aspartate transaminase, alanin transaminase (p<0.05) and serum triacylglyceride (p<0.001) than JNV men. JV women had significantly lower systolic pressure and serum triacylglyceride (p<0.05) than JNV women. CONCLUSIONS: JV men and women had better nutritional characteristics than JNV men and women from the standpoint of lifestyle-related diseases.

Semantic priming effect of metaphor constituent terms.

Camac and Glucksberg reported there was no priming effect between constituent terms of a metaphor and argued that there was no prior similarity or association between the constituents. However, their study had several limitations. An important one was that they neglected the asymmetry of metaphor constituent terms. The purpose of this study is to replicate their experiment under the condition in which one of the constituents preceded the other. The experiment was conducted with Japanese participants using Japanese metaphoric sentences as stimuli. The results showed that the decision was facilitated if the vehicle served as prime and the topic served as target. In contrast, if the topic preceded the vehicle, no priming effect was found. These results are discussed in terms of the class inclusion model proposed earlier by Glucksberg and Keysar.