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1.
Adv Med Educ Pract ; 14: 1435-1443, 2023.
Article in English | MEDLINE | ID: mdl-38149122

ABSTRACT

Background: The spread of the coronavirus disease (COVID-19) has significantly affected medical education. In particular, conducting practical training in a face-to-face format has become difficult. Purpose: To address this problem, online physiology practice combined with team-based learning (TBL) for deep learning of renal physiology was conducted among second-year medical students. Participants and Methods: The experiment was performed by a group of students, while other students watched online. After the experiment, all students were grouped using breakout rooms. Following a discussion of the data, a clinical case study related to the experiment was conducted using TBL. To examine the effect of online practice in a case study under TBL, the participants completed an anonymous, open-ended, web-based questionnaire after the program, enabling us to compare their expectations and satisfaction. The questionnaire consisted of questions examining students' opinions on the appropriateness of online practice, degree of understanding, ease of asking questions, time efficiency, and the usefulness of case studies using TBL. Results: There was no change in the number of students who participated in the online practice before and after class. After class, more students considered the level of understanding easier and displayed better on-time efficiency than with regular face-to-face training. However, these questions are difficult to answer. Conclusion: Online-based physiology practice combined with clinical case studies under TBL helped maintain students' expectations and satisfaction with the training.

2.
J Nutr Sci Vitaminol (Tokyo) ; 68(3): 213-220, 2022.
Article in English | MEDLINE | ID: mdl-35768252

ABSTRACT

The use of dietary supplements has become a common way to maintain good health. This study evaluated the status of supplement use and supplement user characteristics among participants from the Japan Nurses' Health Study, which comprised a cohort of Japanese female nursing professionals. A questionnaire survey covering the use of vitamins and supplements was conducted. Supplements were classified according to their constituents and formulations. Logistic regression analyses were performed to determine the characteristics of supplement users. Results were as follows. There were 4,017 supplement users (34.4% of 11,665 valid answers). The supplement types used were: vitamins (n=2,655), minerals (n=1,121), amino acids and proteins (n=139), botanical products (n=714), animal by-products (n=849), herbal medicines (n=152), nutritional drinks (n=19), others (n=117), and unclassified supplements (n=320). Logistic regression analyses showed that supplement use was significantly associated with age and body mass index, and there were significantly higher proportions of supplement users among pregnant women, black tea drinkers, soy milk consumers, and lactobacillus beverage drinkers. In conclusion, the overall percentage of supplement users was 34.4%. A high prevalence of supplement use was observed among older, non-obese, and pregnant participants, and those who paid more attention to their health. The prevalence of supplement users was significantly higher among those who habitually drank black tea, soy milk, and lactobacillus beverages, suggesting participants used supplements to maintain their health or prevent diseases based on high health consciousness.


Subject(s)
Dietary Supplements , Vitamins , Female , Humans , Japan , Minerals , Pregnancy , Tea
3.
J Interprof Care ; 33(6): 689-696, 2019.
Article in English | MEDLINE | ID: mdl-31020873

ABSTRACT

Communication underpinning well-functioning teamwork is a key mechanism for patient safety. Undergraduate interprofessional education (IPE) provides students with a basic understanding of the psychological factors contributing to teamwork. To develop IPE fostering a collaborative mindset for patient safety, attitudinal changes of students for patient safety were evaluated. Changes in the scores of the modified attitudes toward health care teams scale (ATHCTS) and the modified teamwork attitudes questionnaire (T-TAQ) of students pre- and post-IPE program were evaluated in the 2017 academic year. One hundred and fifty-one students (n=151) of five health professions (medicine, nursing, laboratory science, physiotherapy and occupational therapy) and 125 students of a possible 167 completed the survey before and after the IPE program, respectively. In the modified ATHCTS, 11 out of 14 items showed a significant change. The "quality of care delivery" and "patient-centered care" subscales showed significant increases in the regression factor score. In contrast, only 7 out of 30 items showed a significant increase in the modified T-TAQ. Four out of five categories, however, showed a significant increase, although the factor structure did not correspond to the T-TAQ category structure. The IPE program may have significant capacity to cultivate competencies to collaborate for patient safety. However, development of IPE may require preceding subjects providing concrete knowledge for patient safety, especially for communication and leadership.


Subject(s)
Health Occupations/education , Interprofessional Relations , Patient Safety , Students, Health Occupations/psychology , Cooperative Behavior , Cross-Sectional Studies , Curriculum , Female , Humans , Japan , Male , Patient Care Team , Surveys and Questionnaires , Young Adult
4.
Maturitas ; 121: 41-47, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30704564

ABSTRACT

Results of studies on the associations of soy food intake with urinary estrogen levels in premenopausal women and in postmenopausal women have been inconsistent. We examined the associations of urinary isoflavone levels as well as soy food intake with estrone (E1) and estradiol (E2) in pre- and postmenopausal women. In addition, we compared the levels of isoflavones, E1 and E2 across current hormone users such as those receiving hormone replacement therapy and those using oral contraceptives and non-users among both pre- and postmenopausal women. Urinary levels of isoflavones, E1 and E2 in 498 women (36 hormone users and 462 non-users) were analyzed. Premenopausal women with a higher frequency of soy food intake had higher urinary isoflavone levels, but there were no significant associations between E1 and E2 levels and urinary isoflavone levels. Levels of E1 and E2 in hormone users were significantly lower than those in hormone non-users among premenopausal women, but levels of E1 and E2 in hormone users were significantly higher than those in hormone non-users among postmenopausal women. Postmenopausal women with a higher frequency of soy food intake had higher urinary isoflavone levels, and postmenopausal women with high urinary isoflavone levels had significantly higher E1 and E2 levels. In conclusion, the associations of urinary isoflavone levels with urinary estrogen levels differed with menopausal status. Urinary levels of E1 and E2 were high in postmenopausal women with high urinary isoflavone levels but not in premenopausal women with high urinary isoflavone levels.


Subject(s)
Contraceptives, Oral/therapeutic use , Estrogens/urine , Hormone Replacement Therapy , Isoflavones/urine , Postmenopause/urine , Premenopause/urine , Soy Foods , Estradiol/urine , Estrone/urine , Female , Humans , Middle Aged
5.
PLoS One ; 13(7): e0201318, 2018.
Article in English | MEDLINE | ID: mdl-30048499

ABSTRACT

Equol is one of the most active soy isoflavones. When the association between soy food intake in daily life and health outcomes is examined in epidemiological studies, it is important to define the equol-producing status of each individual. However, few studies have assessed equol-producing status without a soy challenge test. To determine a robust cutoff criterion for equol producer classification in observational studies, we conducted a urinary isoflavone concentration survey in daily life among women. Furthermore, we examined the association between eating habits regarding soy foods and equol-producing status. A total of 4,412 participants were included in the analyses. Urinary isoflavones were analyzed using a high-performance liquid chromatography method. We examined the distribution of the log10 equol/daidzein ratios, finding a mixture of two normal distributions, corresponding to equol producer and non-producer subpopulations. Applying a finite mixture model, we estimated the means, standard deviations, and mixing proportions of these two distributions. The estimation was carried out using the SAS NLIN procedure. The optimal cutoff point for the log10 equol/daidzein ratio in the study population was determined to be -1.42, according to the estimated parameters of the mixture distribution. Based on this criterion, 1,830 (41.5%) of the participants were identified as equol producers. Compared with non-consumers of soy foods, consumers of soy foods had significantly higher odds of being equol producers. Using log10-transformed equol/daidzein ratios ≥ -1.42 to define equol producers among Japanese women is reasonable and suitable for determining equol-producing status in epidemiological studies. We found that soy food eating habits were associated with equol-producing status. Further investigation is required to evaluate associations between equol-producing status in daily life and health outcomes. The results of this study suggest the best cutoff point to use in the definition of equol-producing status in daily life.


Subject(s)
Equol/urine , Isoflavones/urine , Phytoestrogens/urine , Soy Foods , Adult , Cohort Studies , Feeding Behavior , Female , Humans , Japan , Middle Aged
6.
J Biochem ; 159(6): 585-97, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26790472

ABSTRACT

Diacylglycerol (DG) lipase, which hydrolyses 1-stearoyl-2-arachidonyl-sn-glycerol to produce an endocannabinoid, 2-arachidonoylglycerol, was purified from the soluble fraction of rat brain lysates. DG lipase was purified about 1,200-fold by a sequential column chromatographic procedure. Among proteins identified by mass spectrometry analysis in the partially purified DG lipase sample, only DDHD domain containing two (DDHD2), which was formerly regarded as a phospholipase A1, exhibited significant DG lipase activity. Rat DDHD2 expressed in Chinese hamster ovary cells showed similar enzymatic properties to partially purified DG lipase from rat brain. The source of DG lipase activity in rat brain was immunoprecipitated using anti-DDHD2 antibody. Thus, we concluded that the DG lipase activity in the soluble fraction of rat brain is derived from DDHD2. DDHD2 is distributed widely in the rat brain. Immunohistochemical analysis revealed that DDHD2 is expressed in hippocampal neurons, but not in glia.


Subject(s)
Gene Expression Regulation, Enzymologic/physiology , Hippocampus/enzymology , Lipoprotein Lipase , Nerve Tissue Proteins , Neurons/enzymology , Animals , Arachidonic Acids/genetics , Arachidonic Acids/metabolism , CHO Cells , Cloning, Molecular , Cricetinae , Cricetulus , Endocannabinoids/genetics , Endocannabinoids/metabolism , Glycerides/genetics , Glycerides/metabolism , Lipoprotein Lipase/biosynthesis , Lipoprotein Lipase/chemistry , Lipoprotein Lipase/genetics , Lipoprotein Lipase/isolation & purification , Nerve Tissue Proteins/biosynthesis , Nerve Tissue Proteins/chemistry , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/isolation & purification , Neuroglia/enzymology , Protein Domains , Rats
8.
Islets ; 3(4): 150-4, 2011.
Article in English | MEDLINE | ID: mdl-21623172

ABSTRACT

Obese people show marked hyerinsulinemia, but the exact mechanism has not been clarified. Hyperleptinemia is one of possible candidates, although there is an obvious difference in the effect of leptin on insulin secretion between isolated pancreatic islets and ß-cell line. Since glucagon may modulate the effect of leptin on insulin secretion, we determined the influences of glucagon in the leptin effect on insulin secretion. The influences of glucagon in the leptin effect on insulin secretion for 10 minutes were determined by using isolated mouse islets and HIT-T 15 cells. The influences of 3-isobutyl-1- methylxanthine (IBMX), forskolin, and dibutyryl cyclic AMP were investigated in the leptin effect on insulin secretion. Leptin-inhibited insulin and glucagon secretion in isolated mouse pancreatic islets. In contrast, leptin stimulated insulin secretion in isolated mouse islets previously incubated with monoclonal anti-glucagon antibodies for 18 hours. In HIT-T 15 cells, leptin dose-dependently increased insulin secretion, but this effect was attenuated by the addition of glucagon. The stimulatory effect of leptin on insulin secretion was attenuated by 48 hour pre-incubation with glucagon. In the presence of 100 mM IBMX, leptin decreased insulin secretion from HIT-T 15 cells. Leptin also reduced insulin secretion in the presence of 1mM forskolin or 1mM dibutyryl cyclic AMP. The leptin effects on insulin secretion were affected by the existence of glucagon. Intracellular cyclic AMP concentrations may determine the leptin effects on insulin secretion in pancreatic ß-cells.


Subject(s)
Glucagon/metabolism , Insulin-Secreting Cells/metabolism , Insulin/metabolism , Islets of Langerhans/metabolism , Leptin/metabolism , 1-Methyl-3-isobutylxanthine/pharmacology , Animals , Bucladesine/pharmacology , Cell Line , Clone Cells , Colforsin/pharmacology , Cricetinae , Cyclic AMP/agonists , Cyclic AMP/antagonists & inhibitors , Glucagon/antagonists & inhibitors , Insulin Secretion , Insulin-Secreting Cells/drug effects , Islets of Langerhans/drug effects , Male , Mesocricetus , Mice , Mice, Inbred ICR , Phosphodiesterase Inhibitors/pharmacology , Recombinant Proteins/metabolism , Tissue Culture Techniques
9.
Endocr J ; 58(4): 247-56, 2011.
Article in English | MEDLINE | ID: mdl-21325743

ABSTRACT

We have found that ventromedial hypothalamic (VMH) lesions produced by electrocoagulation induce cell proliferation in visceral organs through vagal hyperactivity, and also stimulate regeneration of partially resected liver in rats. To facilitate identification of proliferative and/or regenerative factors at the gene level, we developed electrical production of VMH lesions in mice, for which more genetic information is available compared to rats, and examined the pathophysiological profiles in these mice. Using ddy mice, we produced VMH lesions with reference to the previously reported method in rats. We then examined the pathophysiological profiles of the VMH-lesioned mice. Electrical VMH lesions in mice were produced using the following coordinates: 1.6 mm posterior to the bregma, anteriorly; 0.5 mm lateral to the midsagittal line, transversely; and 0.2 mm above the base of the skull, vertically, with 1 mA of current intensity and 10 s duration. The VMH-lesioned mice showed similar metabolic characteristics to those of VMH-lesioned rats, including body weight gain, increased food intake, increased percentage body fat, and elevated serum insulin and leptin. However, there were some differences in short period of hyperphagia, and in normal serum lipids compared to those of VMH-lesioned rats. The mice showed a similar cell proliferation in visceral organs, including stomach, small intestine, liver, and, exocrine and endocrine pancreas. In conclusion, procedures for development of VMH lesions in mice by electrocoagulation were developed and the VMH-lesioned mice showed pathophysiological profiles similar to those of VMH-lesioned rats, particularly in cell proliferation in visceral organs. These findings have not been observed previously in gold thioglucose-induced VMH-lesioned mice. This model may be a new tool for identifying factors involved in cell proliferation or regeneration in visceral organs.


Subject(s)
Electrocoagulation/methods , Ventromedial Hypothalamic Nucleus/physiopathology , Animals , Cell Proliferation , Disease Models, Animal , Eating , Female , Insulin/blood , Intestine, Small/cytology , Leptin/blood , Lipids/blood , Liver/cytology , Mice , Obesity/etiology , Pancreas/cytology , Rats , Regeneration/physiology , Stomach/cytology
10.
J Diabetes Investig ; 2(6): 423-8, 2011 Nov 30.
Article in English | MEDLINE | ID: mdl-24843525

ABSTRACT

UNLABELLED: Aims/Introduction: The effects of 5-day voluntary exercise on muscle damage and muscle protein degradation were investigated in a streptozotocin-induced rat model of moderately glycemic, uncontrolled, type 2 diabetes. MATERIALS AND METHODS: In the preliminary experiment, an oral glucose tolerance (1.0 g/kg) test was carried out to confirm the development of diabetes 3 days after streptozotocin treatment (30 mg/kg). In the genuine experiment, rats were divided into four groups: (i) non-diabetic rats without exercise (controls); (ii) non-diabetic rats with exercise; (iii) diabetic rats without exercise; and (iv) diabetic rats with exercise. After 5 days of voluntary wheel running exercise, blood and 24-h urine were collected, and levels of serum creatine kinase, a marker of muscle damage, and 24-h urinary excretion of muscle degradation products were determined. RESULTS: Type 2 diabetic rats with insulin deficiency that exercised had higher serum creatine kinase and greater urinary excretions of creatinine, urea nitrogen and 3-methylhistidine compared with both type 2 diabetic rats with insulin deficiency and non-diabetic rats that did not exercise. However, there were no differences in serum creatine kinase and urinary excretions of creatinine, urea nitrogen and 3-methylhistidine between non-diabetic rats that did and did not exercise. CONCLUSIONS: These findings suggest that muscle damage is induced and muscle protein degradation are enhanced by chronic moderate exercise in moderately glycemic uncontrolled type 2 diabetic rats with insulin deficiency at an intensity level of exercise that does not affect muscle damage and muscle protein degradation in non-diabetic rats. (J Diabetes Invest, doi: 10.1111/j.2040-1124.2011.00130.x, 2011).

11.
J Pharmacol Exp Ther ; 332(2): 469-78, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19855098

ABSTRACT

G2A is a G protein-coupled receptor that can be induced by various stressors. G2A is reported to have proton-sensing activity that mediates intracellular inositol phosphate (IP) accumulation with decreasing pH. We previously showed that G2A is also activated by some oxidized free fatty acids such as 9-hydroxyoctadecadienoic acid (9-HODE). In this study, we identified a novel alternative splice variant of G2A (G2A-b) that has a partially different N terminus compared with the G2A originally reported (G2A-a). The two splice variants of G2A show similar tissue distributions, but G2A-b is expressed more abundantly. There was no difference between the two variants in 9-HODE-induced cellular responses, such as intracellular calcium mobilization and GDP/GTP exchange of Galpha protein, and in proton-sensitive IP accumulation. However, G2A-b showed a higher basal activity in terms of IP accumulation. Mutagenesis study revealed that the difference in the basal activity is attributable to the K7 residue that exists only in G2A-a. We further demonstrated that an R42A mutation largely impaired both the basal and proton-sensing activities, but did not affect the 9-HODE-induced intracellular calcium increase. Taken together, we found an additional novel G2A variant (G2A-b) that is the major transcript with functional response to ligand stimulation as well as G2A-a, and succeeded in discriminating proton-sensing and oxidized fatty acid-sensing activities of G2A.


Subject(s)
Alternative Splicing , Cell Cycle Proteins/genetics , Protein Isoforms/genetics , Receptors, G-Protein-Coupled/genetics , Amino Acid Sequence , Animals , CHO Cells , COS Cells , Calcium/metabolism , Cell Cycle Proteins/drug effects , Cell Cycle Proteins/metabolism , Chlorocebus aethiops , Cricetinae , Cricetulus , Cyclic AMP Response Element-Binding Protein A/metabolism , Guanosine Triphosphate/metabolism , HL-60 Cells , Humans , Inositol Phosphates/metabolism , Leukocytes , Linoleic Acids, Conjugated/pharmacology , Molecular Sequence Data , Protein Isoforms/drug effects , Protein Isoforms/metabolism , RNA, Messenger/metabolism , Receptors, G-Protein-Coupled/drug effects , Receptors, G-Protein-Coupled/metabolism , Serum Response Element/physiology , Transfection
12.
Obes Res Clin Pract ; 4(4): e247-342, 2010.
Article in English | MEDLINE | ID: mdl-24345700

ABSTRACT

SUMMARY: The association between degree of obesity and cardiovascular and related metabolic risk factors were examined in 355 Japanese obese school children from 11 to 12 years old. The parameters evaluated were blood pressure, serum lipids, fasting blood glucose, and serum ALT and AST. ALT, AST and triglycerides were more commonly evaluated in obese boys than in obese girls, while HDL-cholesterol was more commonly lowered in obese girls. Hypercholesterolemia was 2-fold, and abnormal liver functions were 3-fold more common in severely obese than in moderate obese children. Thus, cardiovascular and related metabolic risk factors are present in obesity in school-aged children, particularly in boys.:

13.
Biochim Biophys Acta ; 1791(8): 797-805, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19439193

ABSTRACT

Acylprotein thioesterase 1 (APT1), also known as lysophospholipase 1, is an important enzyme responsible for depalmitoylation of palmitoyl proteins. To clarify the substrate selectivity and the intracellular function of APT1, we performed kinetic analyses and competition assays using a recombinant human APT1 (hAPT1) and investigated the subcellular localization. For this purpose, an assay for thioesterase activity against a synthetic palmitoyl peptide using liquid chromatography/mass spectrometry was established. The thioesterase activity of hAPT1 was most active at neutral pH, and did not require Ca(2+) for its maximum activity. The K(M) values for thioesterase and lysophospholipase (against lysophosphatidylcholine) activities were 3.49 and 27.3 microM, and the V(max) values were 27.3 and 1.62 micromol/min/mg, respectively. Thus, hAPT1 revealed much higher thioesterase activity than lysophospholipase activity. One activity was competitively inhibited by another substrate in the presence of both substrates. Immunocytochemical and Western blot analyses revealed that endogenous and overexpressed hAPT1 were mainly localized in the cytosol, while some signals were detected in the plasma membrane, the nuclear membrane and ER in HEK293 cells. These results suggest that eliminating palmitoylated proteins and lysophospholipids from cytosol is one of the functions of hAPT1.


Subject(s)
Thiolester Hydrolases/metabolism , Cell Line , Chromatography, Liquid , Humans , Kinetics , Lysophosphatidylcholines/metabolism , Lysophospholipase/metabolism , Mass Spectrometry , Mutant Proteins/metabolism , Peptides/chemistry , Protein Transport , Subcellular Fractions/enzymology , Thiolester Hydrolases/isolation & purification
14.
Endocr J ; 55(3): 529-33, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18469482

ABSTRACT

Hachimi-jio-gan is widely used to improve several disorders associated with diabetes, but its mechanism remains poorly understood. In an attempt to clarify the mechanism of Hachimi-jio-gan, we investigated the effects of this herbal medicine and its components in transfection studies of CV1 cells, especially nuclear receptor-mediated actions. One half (0.5) mg/ml of Hachimi-jio-gan activated peroxisome proliferator-activated receptor (PPARalpha), mediating the activation by 3.1-fold on DR1 response elements; however, it did not affect PPARgamma, thyroid hormone receptor, androgen receptor, estrogen receptor or RXR. In addition, this activation was observed in a dose-dependent manner. Next, to determine which components of Hachimi-jio-gan activate PPARalpha-mediated transcription, 8 of its components (rehmanniae radix, orni fructus, dioscoreae rhizoma, alismatis rhizoma, hoelen, moutan cortex, cinnamomi cortex, aconiti) were tested. Only cinnamomi cortex (1.0 mg/ml) increased PPARalpha-mediated transcription by 4.1-fold, and this activation was specific for PPAR alpha, and not for other nuclear receptors. Moreover, this PPARalpha-related activation by cinnamomi cortex is specifically observed in renal cells. Taken together, these findings indicate that Hachimi-jio-gan and cinnamomi cortex may have a pharmacological effect through the target site for PPARalpha.


Subject(s)
Drugs, Chinese Herbal/pharmacology , Kidney/drug effects , PPAR alpha/agonists , Plant Extracts/pharmacology , Animals , COS Cells , Cells, Cultured , Chlorocebus aethiops , Cinnamomum zeylanicum , Drugs, Chinese Herbal/chemistry , Humans , Kidney/metabolism , Ligands , Organ Specificity/drug effects , PPAR alpha/genetics , PPAR alpha/metabolism , Transcriptional Activation/drug effects , Transfection
15.
J Invest Dermatol ; 128(5): 1123-33, 2008 May.
Article in English | MEDLINE | ID: mdl-18034171

ABSTRACT

G2A is a stress-inducible G protein-coupled receptor for oxidized free fatty acids, such as 9-hydroxyoctadecadienoic acid (HODE). As skin is routinely and pathologically exposed to many oxidative stresses such as UV radiation, chemical agents, and inflammation that might induce both G2A expression and production of G2A ligands, we examined G2A function in human keratinocytes. G2A was expressed in human epidermis, normal human epidermal keratinocytes (NHEK), and an immortalized human keratinocyte cell line (HaCaT). 9(S)-HODE evoked intracellular calcium mobilization and secretion of cytokines, including IL-6, IL-8, and GM-CSF in NHEK cells. These responses became prominent in HaCaT cells by overexpression of G2A. 9(S)-HODE inhibited proliferation of NHEK cells by suppressing DNA synthesis and arresting the cell cycle in the G0/1-phase. On the other hand, 13(S)-HODE, another major oxidative product from linoleate, showed little or no effect on either cytokine secretion or on proliferation in NHEK cells. A small interfering RNA designed to downregulate G2A caused suppression of 9(S)-HODE-induced inhibitory effects on proliferation of NHEK cells. UVB and H(2)O(2) induced G2A expression and caused oxidation of linoleate to produce 9-HODE in HaCaT cells. These results suggest that 9-HODE-G2A signaling plays proinflammatory roles in skin under oxidative conditions.


Subject(s)
Cell Cycle Proteins/metabolism , Dermatitis/metabolism , Keratinocytes/immunology , Linoleic Acids, Conjugated/metabolism , Oxidative Stress/immunology , Receptors, G-Protein-Coupled/metabolism , Calcium/metabolism , Cell Cycle Proteins/genetics , Cell Division/drug effects , Cell Division/physiology , Cells, Cultured , Cytokines/metabolism , Epidermal Cells , G1 Phase/drug effects , G1 Phase/physiology , Gene Expression/drug effects , Gene Expression/immunology , Gene Expression/radiation effects , Humans , Hydrogen Peroxide/pharmacology , Keratinocytes/cytology , Keratinocytes/metabolism , Linoleic Acids, Conjugated/pharmacology , Oxidants/pharmacology , RNA, Messenger/metabolism , Receptors, G-Protein-Coupled/genetics , Resting Phase, Cell Cycle/drug effects , Resting Phase, Cell Cycle/physiology , Signal Transduction/drug effects , Signal Transduction/immunology , Ultraviolet Rays
16.
Life Sci ; 76(7): 731-41, 2004 Dec 31.
Article in English | MEDLINE | ID: mdl-15581905

ABSTRACT

Troglitazone (TZ), a thiazolidinedione derivative, is a specific ligand for the peroxisome proliferator-activated receptor (PPAR) gamma and improves insulin sensitivity. PPARgamma regulates the expression of genes by binding to PPAR response element in promoter regions of regulator genes as heterodimers with a retinoid X receptor (RXR). We report here that PPARgamma activation by TZ depends on the expression levels of RXR. A transient transfection study in CV-1 cells revealed that the activation by TZ was suppressed by increasing amounts of expression of RXR, but not PPARgamma. Northern blot analysis revealed that PPARgamma and RXR were not expressed in CV-1 cells, and TZ did not induce PPARgamma or RXR mRNA in CV-1 cells indicating that RXR suppression is not related to these endogenous receptor expressions. Electrophoretic mobility shift assay revealed that the increasing amount of RXR did not compete with the DNA binding of the PPARgamma/RXR heterodimer in the presence or absence of TZ. Transfected co-activators enhanced the TZ-dependent gene transcription, and this activation was inhibited by excessive amounts of RXR, indicating that unliganded RXR may recruit the specific coactivators from the PPARgamma/RXR heterodimer.


Subject(s)
Chromans/pharmacology , Hypoglycemic Agents/pharmacology , PPAR gamma/biosynthesis , Retinoid X Receptors/biosynthesis , Thiazolidinediones/pharmacology , Transcription, Genetic/drug effects , Animals , Blotting, Northern , Cell Line, Tumor , Chlorocebus aethiops , Histone Acetyltransferases , Humans , Kidney/cytology , Ligands , Mice , Nuclear Receptor Coactivator 1 , PPAR gamma/analysis , PPAR gamma/genetics , RNA, Messenger/metabolism , Retinoid X Receptors/analysis , Retinoid X Receptors/genetics , Transcription Factors/analysis , Transcription Factors/biosynthesis , Transfection , Troglitazone
17.
J Biol Chem ; 278(49): 49348-57, 2003 Dec 05.
Article in English | MEDLINE | ID: mdl-14507927

ABSTRACT

By using a yeast two-hybrid screen we identified GIPC (GAIP-interacting protein C terminus), a protein with a type I PDZ domain as a novel human lutropin receptor (hLHR) binding partner. Pull-down and immunoprecipitation assays confirmed this interaction and showed that it is dependent on the PDZ domain of GIPC and the C-terminal tetrapeptide of the hLHR. To characterize the functional consequences of the GIPC-hLHR interaction, we used a small interfering RNA against GIPC to generate a clonal cell line that is deficient in GIPC. Studies with this cell line reveal that GIPC is partially responsible for the recycling of the hormone that is internalized by the hLHR and also for maintaining a relatively constant level of hLHR at the cell surface during hormone internalization.


Subject(s)
Carrier Proteins/metabolism , Chorionic Gonadotropin/metabolism , Neuropeptides/metabolism , Receptors, LH/metabolism , Adaptor Proteins, Signal Transducing , Amino Acid Motifs , Amino Acid Sequence , Carrier Proteins/chemistry , Cell Membrane/metabolism , DNA Primers , Endocytosis , Humans , Molecular Sequence Data , Neuropeptides/chemistry , Receptors, LH/chemistry , Sequence Homology, Amino Acid , Two-Hybrid System Techniques
18.
Mol Endocrinol ; 17(3): 411-22, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12554787

ABSTRACT

Although highly homologous in amino acid sequence, the agonist-receptor complexes formed by the human lutropin receptor (hLHR) and rat (r) LHR follow different intracellular routes. The agonist-rLHR complex is routed mostly to a lysosomal degradation pathway whereas a substantial portion of the agonist-hLHR complex is routed to a recycling pathway. In a previous study, we showed that grafting a five-residue sequence (GTALL) present in the C-terminal tail of the hLHR into the equivalent position of the rLHR redirects a substantial portion of the internalized agonist-rLHR complex to a recycling pathway. Using a number of mutations of the GTALL motif, we now show that only the first two residues (GT) of this motif are necessary and sufficient to induce recycling of the internalized agonist-rLHR complex. Phosphoamino acid analysis and mutations of the GT motif show that phosphorylation of the threonine residue is not necessary for recycling. Lastly, we show that addition of portions of the C-terminal tail of the hLHR that include the GT motif to the C-terminal tails of the rat follitropin or murine delta-opioid receptors promotes the post-endocytotic recycling of these G protein-coupled receptors.We conclude that the GT motif present in the C-terminal tail of the hLHR is a transferable motif that promotes the postendocytotic recycling of several G protein-coupled receptors and that the GT-induced recycling does not require the phosphorylation of the threonine residue.


Subject(s)
Follicle Stimulating Hormone/metabolism , GTP-Binding Proteins/metabolism , Receptors, LH/metabolism , Receptors, Opioid, delta/metabolism , Amino Acid Motifs/physiology , Amino Acid Sequence , Animals , Cathepsin D/metabolism , Cells, Cultured , Chorionic Gonadotropin/metabolism , Down-Regulation/physiology , Electrophoresis, Gel, Two-Dimensional , Endocytosis/physiology , Humans , Microscopy, Confocal , Molecular Sequence Data , Phosphoamino Acids/analysis , Precipitin Tests , Rats , Receptors, LH/genetics , Sequence Alignment , rab5 GTP-Binding Proteins/metabolism
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