Physical and Functional Interaction between 5-HT₆ Receptor and Nova-1

5-HT₆ receptor (5-HT₆R) is implicated in cognitive dysfunction, mood disorder, psychosis, and eating disorders. However, despite its significant role in regulating the brain functions, regulation of 5-HT₆R at the molecular level is poorly understood. Here, using yeast two-hybrid assay, we found that human 5-HT₆R directly binds to neuro-oncological ventral antigen 1 (Nova-1), a brain-enriched splicing regulator. The interaction between 5-HT₆R and Nova-1 was confirmed using GST pull-down and co-immunoprecipitation assays in cell lines and rat brain. The splicing activity of Nova-1 was decreased upon overexpression of 5-HT₆R, which was examined by detecting the spliced intermediates of gonadotropin-releasing hormone (GnRH), a known pre-mRNA target of Nova-1, using RT-PCR. In addition, overexpression of 5-HT₆R induced the translocation of Nova-1 from the nucleus to cytoplasm, resulting in the reduced splicing activity of Nova-1. In contrast, overexpression of Nova-1 reduced the activity and the total protein levels of 5-HT₆R. Taken together, these results indicate that when the expression levels of 5-HT₆R or Nova-1 protein are not properly regulated, it may also deteriorate the function of the other.

Treadmill Exercise Alleviates Circadian Rhythm Disruption-Induced Memory Deficits by Activation of Glucocorticoid Receptor and Brain-Derived Neurotrophic Factor-Dependent Pathway / 대한배뇨장애요실금학회지

PURPOSE@#Circadian rhythm affects learning process, memory consolidation, and long-term memory. In this study, the alleviating effect of exercise on circadian rhythm disruption-induced memory deficits was investigated.@*METHODS@#BMAL1 knockdown transgenic mice (BMAL1 TG) were used as the BMAL1-TG group and the BMAL1-TG with treadmill exercise group. Female C57BL/6J mice of the same age were used as the wildtype group and the wildtype with treadmill exercise group. The mice in the treadmill exercise groups performed running on a motorized treadmill under the dark-dark conditions for 8 weeks. Short-term memory, nonspatial object memory, and spatial learning memory were determined using stepdown avoidance test, novel object-recognition test, and radial 8-arm maze test. Immunohistochemistry for doublecortin and 5-bromo-2’-deoxyuridine was conducted for the determination of hippocampal neurogenesis. Using the western blot analysis, we determined the expressions of glucocorticoid receptor (GR) and factors related to the neurogenesis and memory consolidation, such as brain-derived neurotrophic factor, tyrosine kinase B, p44/42 mitogen-activated protein kinase, cyclic AMP-responsive element binding protein, phosphatidylinositol 3-kinase, protein kinas B, protein kinase C alpha, early-growth-response gene 1.@*RESULTS@#Circadian rhythm disruption impaired memory function through inhibiting the expressions of GR and the factors related to neurogenesis and memory consolidation. Treadmill exercise improved memory function via enhancing the expressions of GR and above-mentioned factors.@*CONCLUSIONS@#Treadmill exercise acts as the zeitgeber that improves memory function under the circadian rhythm disrupted conditions.

Circadian Regulation by REV-ERBα Mediates Hippocampal E-LTP in a Time-dependent Manner

Circadian rhythms are driven by circadian oscillators, and these rhythms result in the biological phenomenon of 24-h oscillations. Previous studies suggest that learning and memory are affected by circadian rhythms. One of the genes responsible for generating the circadian rhythm is Rev-erbα. The REV-ERBα protein is a nuclear receptor that acts as a transcriptional repressor, and is a core component of the circadian clock. However, the role of REV-ERBα in neurophysiological processes in the hippocampus has not been characterized yet. In this study, we examined the time-dependent role of REV-ERBα in hippocampal synaptic plasticity using Rev-erbα KO mice. The KO mice lacking REV-ERBα displayed abnormal NMDAR-dependent synaptic potentiation (E-LTP) at CT12~CT14 (subjective night) when compared to their wild-type littermates. However, Rev-erbα KO mice exhibited normal E-LTP at CT0~CT2 (subjective day). We also found that the Rev-erbα KO mice had intact late LTP (L-LTP) at both subjective day and night. Taken together, these results provide evidence that REV-ERBα is critical for hippocampal E-LTP during the dark period.

Simultaneous Molecular Detection of Cryptosporidium and Cyclospora from Raw Vegetables in Korea

Cryptosporidium and Cyclospora are well-known coccidian protozoa that can cause waterborne and foodborne diarrheal illnesses. There have been a few reports regarding contamination in different vegetables with Cryptosporidium, but no data are available regarding the sources of Cyclospora infections in Korea. In the present study, we collected 6 kinds of vegetables (perilla leaves, winter-grown cabbages, chives, sprouts, blueberries, and cherry tomatoes) from July 2014 to June 2015, and investigated contamination by these 2 protozoa using multiplex quantitative real-time PCR. Among 404 vegetables, Cryptosporidium and Cyclospora were detected in 31 (7.7%) and 5 (1.2%) samples, respectively. In addition, Cryptosporidium was isolated from all 6 kinds of vegetables, whereas Cyclospora was detected in 4 kinds of vegetables (except perilla leaves and chives). Cryptosporidium (17.8%) and Cyclospora (2.9%) had the highest detection rates in chives and winter-grown cabbages, respectively. Cryptosporidium was detected all year long; however, Cyclospora was detected only from October to January. In 2 samples (sprout and blueberry), both Cryptosporidium and Cyclospora were detected. Further investigations using TaqI restriction enzyme fragmentation and nested PCR confirmed Cryptosporidium parvum and Cyclospora cayetanensis, respectively. In conclusion, we detected C. cayetanensis in vegetables for the first time in Korea. This suggests that screening should be employed to prevent these protozoal infections in Korea.

Mildly Increased Mechanical Nociceptive Sensitivity in REV-ERBα Knock-out Mice

Nociception is one of the most complex senses that is affected not only by external stimulation but also internal conditions. Previous studies have suggested that circadian rhythm is important in modulating nociception. REV-ERBα knock-out (KO) mice have disrupted circadian rhythm and altered mood-related phenotypes. In this study, we examined the role of REV-ERBα in inflammatory nociception. We found that the nociceptive sensitivity of KO mice was partially enhanced in mechanical nociception. However, this partial alteration was independent of the circadian rhythm. Taken together, deletion of REV-ERBα induced a mild change in mechanical nociceptive sensitivity but this alteration was not dependent on the circadian rhythm.

Detection of Encephalitozoon spp. from Human Diarrheal Stool and Farm Soil Samples in Korea

Microsporidia are eukaryotic organisms that cause zoonosis and are major opportunistic pathogens in HIV-positive patients. However, there is increasing evidence that these organisms can also cause gastrointestinal and ocular infections in immunocompetent individuals. In Korea, there have been no reports on human infections with microsporidia to date. In the present study, we used real-time PCR and nucleotide sequencing to detect Encephalitozoon intestinalis infection in seven of 139 human diarrheal stool specimens (5%) and Encephalitozoon hellem in three of 34 farm soil samples (8.8%). Genotype analysis of the E. hellem isolates based on the internal transcribed spacer 1 and polar tube protein genes showed that all isolates were genotype 1B. To our knowledge, this is the first report on human E. intestinalis infection in Korea and the first report revealing farm soil samples as a source of E. hellem infection. Because microsporidia are an important public health issue, further large-scale epidemiological studies are warranted.

Effect of Mefloquine, a Gap Junction Blocker, on Circadian Period2 Gene Oscillation in the Mouse Suprachiasmatic Nucleus Ex Vivo

BACKGROUND: In mammals, the master circadian pacemaker is localized in an area of the ventral hypothalamus known as the suprachiasmatic nucleus (SCN). Previous studies have shown that pacemaker neurons in the SCN are highly coupled to one another, and this coupling is crucial for intrinsic self-sustainability of the SCN central clock, which is distinguished from peripheral oscillators. One plausible mechanism underlying the intercellular communication may involve direct electrical connections mediated by gap junctions. METHODS: We examined the effect of mefloquine, a neuronal gap junction blocker, on circadian Period 2 (Per2) gene oscillation in SCN slice cultures prepared from Per2::luciferase (PER2::LUC) knock-in mice using a real-time bioluminescence measurement system. RESULTS: Administration of mefloquine causes instability in the pulse period and a slight reduction of amplitude in cyclic PER2::LUC expression. Blockade of gap junctions uncouples PER2::LUC-expressing cells, in terms of phase transition, which weakens synchrony among individual cellular rhythms. CONCLUSION: These findings suggest that neuronal gap junctions play an important role in synchronizing the central pacemaker neurons and contribute to the distinct self-sustainability of the SCN master clock.

Sumoylation of Hes6 Regulates Protein Degradation and Hes1-Mediated Transcription

BACKGROUND: Hes6 is a transcriptional regulator that induces transcriptional activation by binding to transcription repressor Hes1 and suppressing its activity. Hes6 is controlled by the ubiquitin-proteosome-mediated degradation system. Here we investigated the sumoylation of Hes6 and its functional role in its rhythmic expression. METHODS: Hes6, SUMO, and ubiquitin were transfected into HeLa cells and the expression pattern was observed by Western blot and immunoprecipitation. To confirm the effect of sumoylation on the rhythmic expression of Hes6, we generated mouse Hes6 promoter-driven GFP-Hes6 fusion constructs and expressed these constructs in NIH 3T3 cells. RESULTS: Overexpression of SUMO led to sumoylation of Hes6 at both lysine 27 and 30. Protein stability of Hes6 was decreased by sumoylation. Moreover, expression of a Hes6 sumoylation-defective mutant, the 2KR (K27/30R) mutant, or co-expression of SUMO protease SUSP1 with native Hes6, strongly reduced ubiquitination. In addition, sumoylation was associated with both the rhythmic expression and transcriptional regulation of Hes6. Wild type Hes6 showed oscillatory expression with about 2-hour periodicity, whereas the 2KR mutant displayed a longer period. Furthermore, sumoylation of Hes6 derepressed Hes1-induced transcriptional repression. CONCLUSION: Hes6 sumoylation plays an important role in the regulation of its stability and Hes1-mediated transcription. These results suggest that sumoylation may be crucial for rhythmic expression of Hes6 and downstream target genes.

Effect of Resveratrol, a SIRT1 Activator, on the Interactions of the CLOCK/BMAL1 Complex

BACKGROUND: In mammals, the CLOCK/BMAL1 heterodimer is a key transcription factor complex that drives the cyclic expression of clock-controlled genes involved in various physiological functions and behavioral consequences. Recently, a growing number of studies have reported a molecular link between the circadian clock and metabolism. In the present study, we explored the regulatory effects of SIRTUIN1 (SIRT1), an NAD+-dependent deacetylase, on CLOCK/BMAL1-mediated clock gene expression. METHODS: To investigate the interaction between SIRT1 and CLOCK/BMAL1, we conducted bimolecular fluorescence complementation (BiFC) analyses supplemented with immunocytochemistry assays. BiFC experiments employing deletion-specific mutants of BMAL1 were used to elucidate the specific domains that are necessary for the SIRT1-BMAL1 interaction. Additionally, luciferase reporter assays were used to delineate the effects of SIRT1 on circadian gene expression. RESULTS: BiFC analysis revealed that SIRT1 interacted with both CLOCK and BMAL1 in most cell nuclei. As revealed by BiFC assays using various BMAL1 deletion mutants, the PAS-B domain of BMAL1 was essential for interaction with SIRT1. Activation of SIRT1 with resveratrol did not exert any significant change on the interaction with the CLOCK/BMAL1 complex. However, promoter analysis using Per1-Luc and Ebox-Luc reporters showed that SIRT1 significantly downregulated both promoter activities. This inhibitory effect was intensified by treatment with resveratrol, indicating a role for SIRT1 and its activator in CLOCK/BMAL1-mediated transcription of clock genes. CONCLUSION: These results suggest that SIRT1 may form a regulatory complex with CLOCK/BMAL1 that represses clock gene expression, probably via deacetylase activity.

Detection of Cryptosporidium parvum in Environmental Soil and Vegetables

Cryptosporidium parvum is a zoonotic protozoan parasite that causes cryptosporidial enteritis. Numerous outbreaks of cryptosporidiosis have been reported worldwide. Cryptosporidium is transmitted to hosts via consumption of contaminated water and food but also by direct contact with contaminated soil or infected hosts. The present study investigated farm soil collected from 34 locations along the western Korean peninsula and 24 vegetables purchased from local grocery markets in Seoul. The soil and vegetable samples were examined by real-time polymerase chain reaction (qPCR) to estimate the risk of infection. Eleven of 34 locations (32.4%) and 3 of 24 vegetable samples (12.5%) were contaminated with Cryptosporidium parvum, as confirmed by TaqI enzyme digestion of qPCR products and DNA sequencing. It is suggested that Cryptosporidium infection can be mediated via farm soil and vegetables. Therefore, it is necessary to reduce contamination of this organism in view of public health.

Presence of multiple peripheral circadian oscillators in the tissues controlling voiding function in mice

Circadian clocks are the endogenous oscillators that harmonize a variety of physiological processes within the body. Although many urinary functions exhibit clear daily or circadian variation in diurnal humans and nocturnal rodents, the precise mechanisms of these variations are as yet unclear. In the present study, we demonstrate that Per2 promoter activity clearly oscillates in neonate and adult bladders cultured ex vivo from Per2::Luc knock-in mice. In subsequent experiments, we show that multiple local oscillators are operating in all the bladder tissues (detrusor, sphincter and urothelim) and the lumbar spinal cord (L4-5) but not in the pontine micturition center or the ventrolateral periaqueductal gray of the brain. Accordingly, the water intake and urine volume exhibited daily and circadian variations in young adult wild-type mice but not in Per1-/- Per2-/- mice, suggesting a functional clock-dependent nature of the micturition rhythm. Particularly in PDK mice, the water intake and urinary excretion displayed an arrhythmic pattern under constant darkness, and the amount of water consumed and excreted significantly increased compared with those of WT mice. These results suggest that local circadian clocks reside in three types of bladder tissue and the lumbar spinal cord and may have important roles in the circadian control of micturition function.

Spirituality, Death Anxiety and Burnout Levels among Nurses Working in a Cancer Hospital / 한국호스피스완화의료학회지

PURPOSE: This study is to explore the relationships among spirituality, death anxiety and burnout level of nurses caring for cancer patients. METHODS: Participants were 210 nurses from a cancer hospital in Seoul. Data were collected from April until June 2012 and analyzed using t-test, one-way ANOVA, Scheffe's test, and Pearson's correlation coefficient. RESULTS: The mean score for spirituality was 3.51 out of six. Among sub-categories, the one that scored the highest was the purpose and meaning of life, followed by unifying interconnectedness, inner resources and transcendence. The mean score for death anxiety was 3.22, and the sub-categories in the order of high score were denial of death, awareness of the shortness of time, pure death anxiety and fear of matters related to death. For the burnout, the mean was 4.10. Among sub-categories, highest mark was found with emotional exhaustion, followed by depersonalization and personal accomplishment. The spirituality level was negatively correlated with those of death anxiety and burnout. Death anxiety was positively correlated with burnout levels. Nurses with the higher spirituality level also had a higher level of education and experience of spiritual education, believed in the existence of God. In contrast, death anxiety and burnout levels were higher among those with a lower level of education, atheists, and for those who answered that religion has little influence on life. CONCLUSION: Thus, it is necessary to provide spiritual interventions for nurses who care for cancer patients to develop their spirituality, reduce death anxiety and prevent them from burning out easily.

Cryptosporidium hominis Infection Diagnosed by Real-Time PCR-RFLP

There are approximately 20 known species of the genus Cryptosporidium, and among these, 8 infect immunocompetent or immunocompromised humans. C. hominis and C. parvum most commonly infect humans. Differentiating between them is important for evaluating potential sources of infection. We report here the development of a simple and accurate real-time PCR-based restriction fragment length polymorphism (RFLP) method to distinguish between C. parvum and C. hominis. Using the CP2 gene as the target, we found that both Cryptosporidium species yielded 224 bp products. In the subsequent RFLP method using TaqI, 2 bands (99 and 125 bp) specific to C. hominis were detected. Using this method, we detected C. hominis infection in 1 of 21 patients with diarrhea, suggesting that this method could facilitate the detection of C. hominis infections.

2013 Preface: On the Occasion of Publishing the Endocrinology and Metabolism in English

No abstract available.

Mammalian Molecular Clocks

As a consequence of the Earth's rotation, almost all organisms experience day and night cycles within a 24-hr period. To adapt and synchronize biological rhythms to external daily cycles, organisms have evolved an internal time-keeping system. In mammals, the master circadian pacemaker residing in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus generates circadian rhythmicity and orchestrates numerous subsidiary local clocks in other regions of the brain and peripheral tissues. Regardless of their locations, these circadian clocks are cell-autonomous and self-sustainable, implicating rhythmic oscillations in a variety of biochemical and metabolic processes. A group of core clock genes provides interlocking molecular feedback loops that drive the circadian rhythm even at the single-cell level. In addition to the core transcription/translation feedback loops, post-translational modifications also contribute to the fine regulation of molecular circadian clocks. In this article, we briefly review the molecular mechanisms and post-translational modifications of mammalian circadian clock regulation. We also discuss the organization of and communication between central and peripheral circadian oscillators of the mammalian circadian clock.

Biological Rhythms and Neuroendocrine Systems

No abstract available.

Heat shock protein 27 interacts with vimentin and prevents insolubilization of vimentin subunits induced by cadmium

Vimentin is an intermediate filament that regulates cell attachment and subcellular organization. In this study, vimentin filaments were morphologically altered, and its soluble subunits were rapidly reduced via cadmium chloride treatment. Cadmium chloride stimulated three major mitogen-activated protein kinases (MAPKs): extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, and led apoptotic pathway via caspase-9 and caspase-3 activations. In order to determine whether MAPKs were involved in this cadmium-induced soluble vimentin disappearance, we applied MAPK- specific inhibitors (PD98059, SP600125, SB203580). These inhibitors did not abolish the cadmium-induced soluble vimentin disappearance. Caspase and proteosome degradation pathway were also not involved in soluble vimentin disappearance. When we observed vimentin levels in soluble and insoluble fractions, soluble vimentin subunits shifted to an insoluble fraction. As we discovered that heat- shock protein 27 (HSP27) was colocalized and physically associated with vimentin in unstressed cells, the roles of HSP27 with regard to vimentin were assessed. HSP27-overexpressing cells prevented morphological alterations of the vimentin filaments, as well as reductions of soluble vimentin, in the cadmium-treated cells. Moreover, HSP27 antisense oligonucleotide augmented these cadmium-induced changes in vimentin. These findings indicate that HSP27 prevents disruption of the vimentin intermediate filament networks and soluble vimentin disappearance, by virtue of its physical interaction with vimentin in cadmium-treated SK-N-SH cells.

Mobile transposon-like element, clone MTi7: Finding its role(s) by RNA interference / 대한불임학회지

OBJECTIVES: The present study was conducted to evaluate the mobile transposon-like element, clone MTi7 (MTi7) expression in the mouse ovary and to determine its role(s) in the mouse oocytes by RNA interference (RNAi). METHODS: MTi7 mRNA expression was localized by in situ hybridization in day5 and adult ovaries. Double stranded RNA (dsRNA) was prepared for c-mos, a gene with known function as control, and the MTi7. Each dsRNA was microinjected into the germinal vesicle (GV) stage oocytes then oocyte maturation and intracellular changes were evaluated. RESULTS: In situ hybridization analysis revealed that MTi7 mRNA localized to the oocyte cytoplasm from primordial to preovulatory follicles. After dsRNA injection, we found 43-54% GV arrest of microinjected GV oocytes with 68%-90% decrease in targeted c-mos or MTi7 mRNA. CONCLUSIONS: This is the first report of the oocyte-specific expression of the MTi7 mRNA. From results of RNAi for MTi7, we concluded that the MTi7 is involved in the germinal vesicle breakdown in GV oocytes, and MTi7 may be implicated with c-mos for its function. We report here that RNAi provides an outstanding approach to study the function of a gene with unknown functions.

Influence of GnRH Agonist and Neural Antagonists on Stress-blockade of LH and Prolactin Surges Induced by 17 beta-estradiol in Ovariectomized Rats

In our previous study, we demonstrated that immobilization stress blocked estrogen-induced luteinizing hormone(LH) surge possibly by inhibiting the synthesis and release of gonadotropin-releasing hormone (GnRH) at the hypothalamic level and by blocking estrogen-induced prolactin (PRL) surge by increasing the synthesis of dopamine receptor at the pituitary level in ovariectomized rats. The present study was performed to determine whether immobilization stress affects pituitary LH responsiveness to GnRH, and whether endogenous opioid peptide (EOP) and dopamine systems are involved in blocking LH and PRL surges during immobilization stress. Immobilization stress was found to inhibit basal LH release and to completely abolish LH surge. However, the intravenous application of GnRH agonist completely restored immobilization-blocked LH surge and basal LH release. Treatment with naloxone did not exert any effect on immobilization-blocked LH surge but increased basal LH release during immobilization stress. Pimozide did not affect immobilization-blocked LH surge or basal LH release. Naloxone also decreased immobilization-induced basal PRL release, but had no effect on immobilization-blocked PRL surge. Immobilization-increased basal PRL levels were augmented by pimozide treatment and immobilization-blocked PRL surge was dramatically restored by pimozide. We conclude that immobilization stress does not impair pituitary LH response to GnRH, and that the immobilization stress-induced blockage of LH surge is probably not mediated by either the opioidergic or the dopaminergic system. However, immobilization-blockade of PRL surge may be partly mediated by the dopaminergic system.

Patterns of Circulating Gonadotropins (LH and FSH), Prolactin and Ovarian Steroids (Estradiol and Progesterone) during the Menstrual Cycle in Korean Women

Serum levels of LH, FSH and prolactin and plasma levels of estradiol and progesterone were measured by radioimmunoassay from 8 healthy volunteers on no medication for at least 3 months prior to study and with histories of regular menstrual cycle. The following criteria were used to define a normal menstrual cycle:1) mid-cycle LH surge, 2) luteal phase duration between 12 and 16 days, 3) plasma progesterone levels above 5 ng/m1 5-10 days after LH surge. Six of eight cycles studied were considered normal. Serum levels of LH from 6 women were fair1y constant through the cycle, except at midcycle, when a surge occurred. The rapid increase of LH secretion was during the late follicular phase with a mean peak value of 147.5 mIU/ml. Concentration of FSH started to rise after the onset of menses and decreased slight1y during the late follicular phase. FSH rose sharply at midcycle with a mean peak value reaching 36.8 mIU/ml. Following the midcycle FSH and LH surge, FSH and LH decreased sharply and remained at lower concentration during the luteal phase than during the follicular phase. Serum prolactin concentrations fluctuated throughout the menstrual cycle. There was no peak value of prolactin concomitant to the LH peak. Plasma estradiol gradually increased during the follicular phase reaching a maximum of 354.3 pg/ml prior the midcycle LH surge. Following its peak, the level of estradiol dropped sharply and started to increase from the 3rd day after LH peak, rising to 235.9 pg/ml during the midluteal peak. Plasma progesterone levels remained consistently low during the follicular phase and started to rise after the midcycle surge of LH. This rise persisted from day 5 to day 9 after the LH surge, showing a mean value of 26.1 ng/m1. Afterward, a sharp decline occurred resulting in menstruation. Two cycles studied were considered abnormal. Both cycles showed a "short luteal phase".