The SATB1-MIR22-GBA axis mediates glucocerebroside accumulation inducing a cellular senescence-like phenotype in dopaminergic neurons

Idiopathic Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, which is associated with neuroinflammation and reactive gliosis. The underlying cause of PD and the concurrent neuroinflammation are not well understood. In this study, we utilize human and murine neuronal lines, stem cell-derived dopaminergic neurons, and mice to demonstrate that three previously identified genetic risk factors for PD, namely SATB1, MIR22HG, and GBA, are components of a single gene regulatory pathway. Our findings indicate that dysregulation of this pathway leads to the upregulation of glucocerebrosides (GluCer), which triggers a cellular senescence-like phenotype in dopaminergic neurons. Specifically, we discovered that downregulation of the transcriptional repressor SATB1 results in the derepression of the microRNA miR-22-3p, leading to decreased GBA expression and subsequent accumulation of GluCer. Furthermore, our results demonstrate that an increase in GluCer alone is sufficient to impair lysosomal and mitochondrial function, thereby inducing cellular senescence. Dysregulation of the SATB1-MIR22-GBA pathway, observed in both PD patients and normal aging, leads to lysosomal and mitochondrial dysfunction due to the GluCer accumulation, ultimately resulting in a cellular senescence-like phenotype in dopaminergic neurons. Therefore, our study highlights a novel pathway involving three genetic risk factors for PD and provides a potential mechanism for the senescence-induced neuroinflammation and reactive gliosis observed in both PD and normal aging.

The SATB1-MIR22-GBA axis mediates glucocerebroside accumulation inducing a cellular senescence-like phenotype in dopaminergic neurons

Idiopathic Parkinson's Disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, which is associated with neuroinflammation and reactive gliosis. The underlying cause of PD and the concurrent neuroinflammation are not well understood. In this study, we utilized human and murine neuronal lines, stem cell-derived dopaminergic neurons, and mice to demonstrate that three previously identified genetic risk factors for PD, namely SATB1, MIR22HG, and GBA, are components of a single gene regulatory pathway. Our findings indicate that dysregulation of this pathway leads to the upregulation of glucocerebrosides (GluCer), which triggers a cellular senescence-like phenotype in dopaminergic neurons. Specifically, we discovered that downregulation of the transcriptional repressor SATB1 results in the derepression of the microRNA miR-22-3p, leading to decreased GBA expression and subsequent accumulation of GluCer. Furthermore, our results demonstrate that an increase in GluCer alone is sufficient to impair lysosomal and mitochondrial function, thereby inducing cellular senescence dependent on S100A9 and stress factors. Dysregulation of the SATB1-MIR22-GBA pathway, observed in both PD patients and normal aging, leads to lysosomal and mitochondrial dysfunction due to the GluCer accumulation, ultimately resulting in a cellular senescence-like phenotype in dopaminergic neurons. Therefore, our study highlights a novel pathway involving three genetic risk factors for PD and provides a potential mechanism for the senescence-induced neuroinflammation and reactive gliosis observed in both PD and normal aging.

Chemical reprogramming takes the fast lane

Small molecule-induced cell fate transitions are characterized by low efficiency and slow kinetics. An optimized chemical reprogramming approach now facilitates the robust and rapid conversion of somatic cells to pluripotent stem cells, unlocking exciting avenues to study and manipulate human cell identity.

Mask-induced dermatoses during the COVID-19 pandemic: a questionnaire-based study in 12 Korean hospitals

BACKGROUND

During the coronavirus disease 2019 (COVID-19) pandemic, various adverse skin reactions to long-term mask wearing have been reported.

AIM

To assess the clinical features of mask-induced dermatoses and to recommend prevention and treatment options.

METHODS

From April to August 2020, questionnaires including topics such as demographic information, pre-existing skin disorders, reported mask-related symptoms, daily mask-wearing duration and frequency, types of masks used and whether the participant was a healthcare worker, were distributed to patients in 12 hospitals. Dermatologists assessed skin lesions, confirmed diagnosis and recorded treatments.

RESULTS

Itchiness was the most frequent symptom, mostly affecting the cheeks. The most common skin disease was new-onset contact dermatitis (33.94%), followed by new-onset acne (16.97%) and worsening of pre-existing acne (16.97%). Daily wearing of masks was significantly (P = 0.02) associated with new-onset contact dermatitis. More than half of patients with pre-existing skin problems experienced disease worsening while wearing masks. Longer duration of wearing (> 6 h/day, P = 0.04) and use of cotton masks (P < 0.001) significantly increased acne flare-up. Healthcare workers had a higher incidence of skin disease. Skin lesions were generally mild and well tolerated with topical treatment. The study had some limitations: the effect of seasonal characteristics and other risk factors were not assessed, and the patients were visiting dermatological clinics and had interest in their skin status, thus, there may have been selection bias.

CONCLUSION

Mask-induced/-triggered dermatoses contribute to increase the dermatological burden during the pandemic.

Association of blood pressure classification using the 2017 ACC/AHA guidelines with the progression of coronary artery calcification

Funding Acknowledgements

Type of funding sources: None.

Aims

The recent American College of Cardiology/American Heart Association guidelines reinforced the criteria for diagnosis of hypertension. We assessed the association of this reinforced criteria with coronary artery calcification (CAC) progression in asymptomatic adults according to different age groups.

Methods and results

We included 10,839 asymptomatic Korean adults (23.4% aged ≤45 years) who underwent at least two coronary artery calcium score (CACS) evaluations between 2012 and 2016. All participants were categorised into normal blood pressure (BP) (untreated systolic/diastolic &lt;120/&lt;80 mmHg), elevated BP (untreated systolic/diastolic 120–129/&lt;80 mmHg), stage 1 hypertension (untreated systolic/diastolic BP 130–139/80–89 mmHg), or stage 2 hypertension (systolic/diastolic BP ≥140/≥90 mmHg or taking anti-hypertensive medication) groups. CAC progression was defined as a difference ≥2.5 between the square roots (√) of the baseline and follow-up CACSs (Δ√transformed CACS). During a mean 3.3-year follow-up, the incidence of CAC progression was 13.5% and 36.3% in groups with ≤45 and &gt;45 years, respectively. After multivariable adjustment for sex, diabetes, dyslipidaemia, obesity, current smoking, and baseline CACS, hazard ratios (95% confidence interval) for CAC progression versus normal BP in elevated BP, stage 1 hypertension, and stage 2 hypertension were 1.39 (0.93–2.07)(P = 0.107), 1.59 (1.17–2.17)(P = 0.003), and 2.38 (1.82–3.12)(P &lt;0.001) in the ≤45 years group and 1.13 (0.97–1.32)(P = 0.111), 1.20 (1.06–1.34)(P = 0.003), and 1.72 (1.57–1.87)(P &lt;0.001) in the &gt;45 years group.

Conclusion

Newly defined stage 1 hypertension is independently associated with CAC progression in asymptomatic Korean adults irrespective of different age groups.

Investigation of photodarkening in tandem-pumped Yb-doped fibers

Investigation of photodarkening (PD) in Yb-doped fibers tandem-pumped at 1018 nm is reported. For a homemade Yb-doped aluminosilicate double-clad fiber (YADF), the transmitted power of a 633 nm probe beam is reduced by 2.4% over 2 hours for the tandem pumping configuration at 1018 nm, which is significantly smaller than 33.3% for a laser diode (LD) pumping at 976 nm. A tandem-pumped Yb fiber amplifier also shows a much smaller decrease in the amplified output power over time than a LD-pumped Yb fiber amplifier. Based on fluorescence spectra of the YADF, we can not only associate PD of the YADF to intrinsic oxygen deficiency centers or Tm³⁺ impurities but also confirm the impact of the excited Yb³⁺ ion density on PD. The benefits of the tandem pumping in a high-power Yb fiber laser system will be discussed.

P4339Reference values for cardiorespiratory fitness in healthy Koreans: compared to western nations and nomogram

Introduction

Cardiorespiratory Fitness (CRF), defined as the integrated ability to properly oxygenate skeletal muscles during physical activity, is associated with a high risk of cardiovascular disease and all-cause mortality. The reference range for CRF may differ among nations, with Asians under-represented in previous data.

Purpose

In this study, we sought to establish reference values of CRF for Asians using a recent Korean cohort.

Methods

We analyzed 2646 healthy Korean adults recently enrolled in the Korea Institute of Sports Science Fitness Standards (KISS FitS) project with estimated maximal oxygen uptake (VO2max) values during treadmill test. Patients with cardiovascular or renal disease, systemic infection, pregnant women and those with orthopedic injuries unable to measure physical fitness were excluded. Age-specific mean VO2max values were compared with those from recent American, Norwegian, Danish cohorts and old Korean data.

Results

Age-specific reference values for healthy Korean adults in this cohort were as shown (Table). We were able to draw a nomogram to predict exercise capacity for a given age and MET value (Figure). When compared to other countries, less CRF reduction by aging was seen in Asians than in other Westerners. When compared to old Korean data from the 1980s, values were similar after adjustment for difference in methods, except for those under 30 years old which were decreased.

Exercise capacity of healthy Korean Men Women Age VO2max (ml/kg/min) N P-value for trend Age VO2max (ml/kg/min) N P-value for trend 19–29 42.3±6.3± 209 <0.01 19–29 34.3±4.3± 110 <0.01 30–39 42.0±5.0± 170 39–39 32.2±4.5± 211 40–49 41.4±5.6± 238 40–49 30.8±4.6± 284 50–59 38.0±5.7± 274 50–59 28.3±4.6± 367 60–69 32.4±6.2± 134 60–69 26.0±5.7± 336 70–79 27.2±5.6± 83 70–79 23.9±4.4± 195 >80 24.1±4.0± 11 >80 21.0±3.7± 24 Total 38.6±7.4± 1119 Total 28.5±5.8 1527 Data are presented as mean ± standard deviation. VO2max, maximal oxygen uptake; N, number.

Nomogram of exercise capacity in Koreans

Conclusions

While there was no significant change in CRF over time in the same ethnic group, there was a clear inter-ethnic difference. CRF should be assessed according to ethnic or national standards, and it is necessary to establish a reference for each nation or ethnicity with periodic updates.

Acknowledgement/Funding

National Sports Promotion Fund of the Korea Sports Promotion Foundation in 2015

P2501Validation of FRIEND and ACSM equations for cardiorespiratory fitness: comparison to direct measurement in male CAD patients

Introduction

Cardiorespiratory fitness (CRF) is associated with a high risk of cardiovascular disease and all-cause mortality. The regression equation of American College of Sports Medicine (ACSM) was a preferred method for estimating maximal oxygen consumption (VO2max). It is well-known that CRF is overestimated in ACSM equation. Recently, Kokkinos reported more precise equation from the Fitness Registry and the Importance of Exercise National Database (FRIEND). Both equations were made from western healthy people.

Purpose

In this study, we compared VO2max estimated by ACSM and FRIEND equations to VO2max directly measured in male coronary artery disease (CAD) patients.

Methods

We analyzed 103 male CAD patients who underwent percutaneous coronary intervention and who participated in cardiac rehabilitation between June 2015 and December 2018. VO2max was directly measured by the gas exchange analysis during treadmill test with modified Bruce protocol. Exclusive criteria were pulmonary disease, chronic kidney disease on hemodialysis, malignancy, peripheral artery disease, insufficient cardiopulmonary exercise test and orthopedic injuries. Directly measured VO2max were compared to ACSM and FRIEND equations.

Results

Age-specific VO2max values, which were directly measured from male CAD patients, were shown in Table. Smaller CRF difference was shown in FRIEND equation than ACSM equation. Compared to the measured value, CRF estimated by ACSM equation was overestimated by 22%, but the one estimated by FRIEND equation had only 2% gap. Figure presents Bland-Altman plots. ACSM equation had the higher bias (5.52ml/kg/min) compared with FRIEND equation (0.200ml/kg/min).

Comparison table of VO2max estimated by ACSM and FRIEND equations with directly measured VO2max in male CAD patients Age Number VO2max (ml/kg/min) Measured ACSM % predicted FRIEND % predicted 30–39 4 29.5 ± (6.6) 35.7 ± (6.1) 122.3 ± (8.5) 29.1 ± (4.3) 100.1 ± (8.7) 40–49 20 29.1 ± (5.1) 35.7 ± (5.4) 123.6 ± (11.1) 29.1 ± (3.8) 101.2 ± (9.5) 50–59 32 25.6 ± (4.3) 31.5 ± (5.1) 123.8 ± (10.1) 26.2 ± (3.6) 103.2 ± (8.5) 60–69 27 26.0 ± (5.1) 31.1 ± (2.6) 120.5 ± (12.6) 25.9 ± (4.0) 100.8 ± (10.5) 70–79 18 21.2 ± (6.0) 26.8 ± (5.4) 123.2 ± (14.8) 22.8 ± (3.9) 105.2 ± (12.0) >80 2 25.0 ± (10.1) 22.8 ± (2.6) 97 ± (28.9) 19.9 ± (1.9) 85.1 ± (27.0) Total 103 25.7 ± (5.6) 31.4 ± (6.0) 122.2 ± (12.4) 26.1 ± (4.3) 102.1 ± (10.4) Data are presented as mean ± (standard deviation).

Bland-Altman plots

Conclusions

FRIEND equation can estimate CRF more accurately than ACSM equation, even in Asian patients with CAD.

Loss of SATB1 Induces p21-Dependent Cellular Senescence in Post-mitotic Dopaminergic Neurons

Cellular senescence is a mechanism used by mitotic cells to prevent uncontrolled cell division. As senescent cells persist in tissues, they cause local inflammation and are harmful to surrounding cells, contributing to aging. Generally, neurodegenerative diseases, such as Parkinson's, are disorders of aging. The contribution of cellular senescence to neurodegeneration is still unclear. SATB1 is a DNA binding protein associated with Parkinson's disease. We report that SATB1 prevents cellular senescence in post-mitotic dopaminergic neurons. Loss of SATB1 causes activation of a cellular senescence transcriptional program in dopamine neurons both in human stem cell-derived dopaminergic neurons and in mice. We observed phenotypes that are central to cellular senescence in SATB1 knockout dopamine neurons in vitro and in vivo. Moreover, we found that SATB1 directly represses expression of the pro-senescence factor p21 in dopaminergic neurons. Our data implicate senescence of dopamine neurons as a contributing factor in the pathology of Parkinson's disease.

Therapeutic effects of kefir grain Lactobacillus-derived extracellular vesicles in mice with 2,4,6-trinitrobenzene sulfonic acid-induced inflammatory bowel disease

Kefir is a fermented product from yeast and lactic acid bacteria, and has been associated with various health benefits including relieving inflammatory bowel disease. Recently, it has been shown that gram-positive bacteria produce extracellular vesicles (EV). The EV could be appearing as potentially important mediators of cell to cell interaction. In this study, we explored the role of kefir grain Lactobacillus-derived EV in modulating inflammation responses via alleviating the production of inflammatory cytokines in tumor necrosis factor-α (TNF-α)-induced inflammation in Caco-2 cells and the 2,4,6-trinitrobenzene sulfonic acid-induced inflammatory bowel disease mouse model. Kefir-derived Lactobacillus EV were isolated by ultracentrifugation of the culture medium of 3 different kefir-derived strains (i.e., Lactobacillus kefir, Lactobacillus kefiranofaciens, and Lactobacillus kefirgranum). Nanoparticle tracking analysis showed that the size of isolated kefir-derived Lactobacillus EV was within 80 to 400 nm, and kefir-derived Lactobacillus EV uptake into recipient Caco-2 cells was confirmed by fluorescence labeling. Treatment of each kefir-derived Lactobacillus EV onto TNF-α-stimulated Caco-2 cells significantly reduced the level of both mRNA expression and secretion of IL-8, and Western blot analysis revealed that such an effect was related to inhibition of TNF-α signaling mediated by reducing the phosphorylation of p65, a subunit of NF-kB. Subsequent administration of kefir-derived Lactobacillus EV into inflammatory bowel disease-induced mice significantly alleviated the body weight loss and rectal bleeding, and enhanced stool consistency. Histological examination showed that kefir-derived Lactobacillus EV substantially reduced the infiltration of transmural leukocytes and loss of goblet cells within the colon, and the serum level of myeloperoxidase was significantly lower in the EV-treated group than control group. Our study demonstrates that kefir-derived Lactobacillus EV can be potentially used for developing innovative strategies for alleviating inflammatory bowel disease.

Development of immune and microbial environments is independently regulated in the mammary gland

Breastfeeding is important for mammals, providing immunological and microbiological advantages to neonates, together with the nutritional supply from the mother. However, the mechanisms of this functional diversity in the mammary gland remain poorly characterized. Here, we show that, similar to the gastrointestinal tract, the mammary gland develops immune and microbial environments consisting of immunoglobulin A (IgA) and the microflora, respectively, both of which are important for protecting neonates and the mother from infectious diseases. The IgA production and microflora development are coordinated in the gastrointestinal tract but seem to be independently regulated in the mammary gland. In particular, the chemokine (C-C motif) ligand 28 and poly-Ig receptor, crucial molecules for the IgA production in milk, were expressed normally in germ-free lactating mice but were almost undetectable in postweaning mothers, regardless of the microflora presence. Our findings offer insights into potentially improving the quality of breastfeeding, using both immunological and microbiological approaches.

Retinoblastoma protein (Rb) links hypoxia to altered mechanical properties in cancer cells as measured by an optical tweezer

Hypoxia modulates actin organization via multiple pathways. Analyzing the effect of hypoxia on the biophysical properties of cancer cells is beneficial for studying modulatory signalling pathways by quantifying cytoskeleton rearrangements. We have characterized the biophysical properties of human LNCaP prostate cancer cells that occur in response to loss of the retinoblastoma protein (Rb) under hypoxic stress using an oscillating optical tweezer. Hypoxia and Rb-loss increased cell stiffness in a fashion that was dependent on activation of the extracellular signal-regulated kinase (ERK) and the protein kinase B (AKT)- mammalian target of rapamycin (MTOR) pathways. Pharmacological inhibition of MEK1/2, AKT or MTOR impeded hypoxia-inducible changes in the actin cytoskeleton and inhibited cell migration in Rb-deficient cells conditioned with hypoxia. These results suggest that loss of Rb in transformed hypoxic cancer cells affects MEK1/2-ERK/AKT-MTOR signalling and promotes motility. Thus, the mechanical characterization of cancer cells using an optical tweezer provides an additional technique for cancer diagnosis/prognosis and evaluating therapeutic performance.

A cascaded two-step Kalman filter for estimation of human body segment orientation using MEMS-IMU

Orientation of human body segments is an important quantity in many biomechanical analyses. To get robust and drift-free 3-D orientation, raw data from miniature body worn MEMS-based inertial measurement units (IMU) should be blended in a Kalman filter. Aiming at less computational cost, this work presents a novel cascaded two-step Kalman filter orientation estimation algorithm. Tilt angles are estimated in the first step of the proposed cascaded Kalman filter. The estimated tilt angles are passed to the second step of the filter for yaw angle calculation. The orientation results are benchmarked against the ones from a highly accurate tactical grade IMU. Experimental results reveal that the proposed algorithm provides robust orientation estimation in both kinematically and magnetically disturbed conditions.

Relative adrenal insufficiency in chronic liver disease: its prevalence and effects on long-term mortality

BACKGROUND

The relationship between relative adrenal insufficiency (RAI) and chronic liver disease is unclear.

AIM

To determine the frequency with which RAI is observed in noncritically ill patients at various stages of chronic liver disease, and the correlation between RAI and disease severity and long-term mortality.

METHODS

In total, 71 non-critically ill patients with liver cirrhosis (n = 54) and chronic hepatitis (n = 17) were evaluated prospectively. A short stimulation test (SST) with 250 μg of corticotrophin was performed to detect RAI. RAI was defined as an increase in serum cortisol of <9 μg/dL in patients with a basal total cortisol of <35 μg/dL.

RESULTS

RAI was observed in only 13 (24.1%) of 54 patients with cirrhosis. Compared to those without RAI, cirrhotic patients with RAI had significantly higher Child-Turcotte-Pugh score (10.3 ± 1.7 vs. 7.1 ± 1.8, mean ± s.d., P < 0.001) and Model for End-Stage Liver Disease score (14.5 ± 6.6 vs. 9.4 ± 3.7, P = 0.017). The cortisol response to corticotropin was negatively correlated with the severity of cirrhosis (P < 0.05). In addition, the mortality rate was higher in cirrhotic patients with RAI (69.2%) than in those without RAI (4.9%; P < 0.001) during the follow-up period of 20.1 ± 13.5 months (range, 5.8-51.1 months). The cumulative 1-year survival rates in cirrhotic patients with and without RAI were 69.2% and 95.0%, respectively (P = 0.05), while the corresponding cumulative 3-year survival rates were 0% and 95.0% (P < 0.001).

CONCLUSIONS

Relative adrenal insufficiency is more commonly observed in those with severe cirrhosis, and is clearly associated with more advanced liver disease and a shortened long-term survival. This suggests that relative adrenal insufficiency is an independent prognostic factor in non-critically ill patients with cirrhosis.

β-Lapachone induces programmed necrosis through the RIP1-PARP-AIF-dependent pathway in human hepatocellular carcinoma SK-Hep1 cells

β-Lapachone activates multiple cell death mechanisms including apoptosis, autophagy and necrotic cell death in cancer cells. In this study, we investigated β-lapachone-induced cell death and the underlying mechanisms in human hepatocellular carcinoma SK-Hep1 cells. β-Lapachone markedly induced cell death without caspase activation. β-Lapachone increased PI uptake and HMGB-1 release to extracellular space, which are markers of necrotic cell death. Necrostatin-1 (a RIP1 kinase inhibitor) markedly inhibited β-lapachone-induced cell death and HMGB-1 release. In addition, β-lapachone activated poly (ADP-ribosyl) polymerase-1(PARP-1) and promoted AIF release, and DPQ (a PARP-1 specific inhibitor) or AIF siRNA blocked β-lapachone-induced cell death. Furthermore, necrostatin-1 blocked PARP-1 activation and cytosolic AIF translocation. We also found that β-lapachone-induced reactive oxygen species (ROS) production has an important role in the activation of the RIP1-PARP1-AIF pathway. Finally, β-lapachone-induced cell death was inhibited by dicoumarol (a NQO-1 inhibitor), and NQO1 expression was correlated with sensitivity to β-lapachone. Taken together, our results demonstrate that β-lapachone induces programmed necrosis through the NQO1-dependent ROS-mediated RIP1-PARP1-AIF pathway.

Species-specific challenges in dog cloning

Somatic cell nuclear transfer (SCNT) is now an established procedure used in cloning of several species. SCNT in dogs involves multiple steps including the removal of the nuclear material, injection of a donor cell, fusion, activation of the reconstructed oocytes and finally transfer to a synchronized female recipient. There are therefore many factors that contribute to cloning efficiency. By performing a retrospective analysis of 2005-2012 published papers regarding dog cloning, we define the optimum procedure and summarize the specific feature for dog cloning.

Association between urine cotinine levels, continuous performance test variables, and attention deficit hyperactivity disorder and learning disability symptoms in school-aged children

BACKGROUND

We examined the cross-sectional relationship between environmental tobacco smoke exposure, continuous performance test (CPT) measures, and attention deficit hyperactivity disorder (ADHD) or learning disability symptoms in school-aged children.

METHOD

In total, 989 children (526 boys, mean age 9.1 ± 0.7 years), recruited from five South Korean cities participated in this study. We used urine cotinine as a biomarker for environmental tobacco smoke exposure, and obtained the children's scores on a CPT. Parents completed the Korean versions of the ADHD rating scale-IV (ADHD-RS) and learning disability evaluation scale (LDES). Using generalized linear mixed model (GLMM), we assessed the associations between urine cotinine concentrations, neuropsychological variables, and symptoms of ADHD and learning disabilities. Additionally, we conducted structural equation models to explore the effects' pathways.

RESULTS

After adjusting for a range of relevant covariates, GLMM showed urinary cotinine levels were significantly and positively associated with CPT scores on omission errors, commission errors, response time, and response time variability, and with parent- and teacher-rated ADHD-RS scores. In addition, urine cotinine levels were negatively associated with LDES scores on spelling and mathematical calculations. The structural equation model revealed that CPT variables mediated the association between urine cotinine levels and parental reports of symptoms of ADHD and learning disabilities.

CONCLUSIONS

Our data indicate that environmental exposure to tobacco smoke is associated with ADHD and learning disabilities in children, and that impairments in attention and inhibitory control probably mediate the effect.

Comparison of cell proliferation and epigenetic modification of gene expression patterns in canine foetal fibroblasts and adipose tissue-derived mesenchymal stem cells

OBJECTIVES

This study compared rate of cell proliferation, viability, cell size, expression patterns of genes related to pluripotency and epigenetic modification between canine foetal fibroblasts (cFF) and canine adipose tissue-derived mesenchymal stem cells (cAd-MSC).

MATERIALS AND METHODS

Proliferation pattern, cell viability as well as cell size at each passage of cFF and cAd-MSC were measured when cultures reached confluence. In addition, real-time PCR was performed to investigate expression of Dnmt1, HDAC1, OCT4, SOX2, BAX, BCL2 genes with reference to β-actin gene expression as an endogenous control in both cell lines.

RESULTS

cFF and cAd-MSC differed in number of generations, but not in doubling times, at all passages. Mean cell size of cAd-MSC was significantly smaller than that of cFF. Cell viability was significantly lower in cFFs and apoptotic level was significantly lower in cAd-MSC compared to passage-matched cFF. In the expression of genes related to pluripotency and epigenetic modification, level of HDAC1 in cAd-MSC was significantly higher than in cFF, but expression of Dnmt1 did not differ between the two groups. OCT4 and SOX2 were significantly more highly expressed in cAd-MSC compared to cFF.

CONCLUSIONS

cAd-MSC have higher stem-cell potential than cFF in terms of proliferation patterns, epigenetic modification and pluripotency, thus cAd-MSC could be more appropriate than cFF as donors of nuclei in somatic cell nuclear transfer for transgenesis.

Anti-elastase and anti-hyaluronidase of phenolic substance from Areca catechu as a new anti-ageing agent

We have previously screened 150 medicinal plants for the inhibition of elastase and found significant inhibitory effects of the extracts of Areca catechu L. on the ageing and inflammation of skin tissues. To isolate and identify the compounds having biological activity, they were further purified by each fraction of solvents, silica gel column chromatography, preparative TLC and reversed-phase HPLC. The peak in HPLC, which coincided with the inhibitory activity against elastase, was identified as a phenolic substance by using various colorimetric methods, UV and IR. IC(50) values of this phenolic substance were 26.9 mug mL(-1) for porcine pancreatic elastase (PPE) and 60.8 mug mL(-1) for human neutrophil elastase (HNE). This phenolic substance showed more potent activity than that of reference compounds, oleanolic acid (76.5 mug mL(-1) for PPE, 219.2 mug mL(-1) for HNE) and ursolic acid (31.0 mug mL(-1) for PPE, 118.6 mug mL(-1) for HNE). According to the Lineweaver-Burk plots, the inhibition against both PPE and HNE by this phenolic substance was competitive inhibition with the substrate. The phenolic substance from A. catechu effectively inhibited hyaluronidase activity (IC(50) : 210 mug mL(-1) ). These results suggest that the phenolic substance purified from A. catechu has an anti-ageing effect by protecting connective tissue proteins.

Secular trends in adult male smoking from 1992 to 2006 in South Korea: age-specific changes with evolving tobacco-control policies

OBJECTIVES

For years, South Korea has had one of the highest levels of tobacco use among males in the world, but a steady decline has been observed recently. This study examined how the smoking behaviour of male adults changed with age after the implementation of national tobacco control policies in 1995.

STUDY DESIGN

Repeated cross-sectional study using a national survey.

METHODS

Data were obtained from the 1992, 1995, 1999, 2003 and 2006 results of a repeated cross-sectional survey, the Social Statistics Survey. The smoking status of adult men was compared before (1992 and 1995 surveys) and after (1999, 2003 and 2006 surveys) the implementation of government-directed tobacco control policies using graphical methods and logistic regression analysis.

RESULTS

After the implementation of tobacco control policies, the percentage of current male smokers decreased while the percentage of former smokers increased markedly. Smoking prevalence among older men (aged 50 years or more) reduced initially, and this decline was more pronounced after the tobacco control policies were implemented. Smoking prevalence in younger men (aged 30-49 years) declined in 2003 when more comprehensive tobacco control policies were implemented.

CONCLUSIONS

This study suggests that comprehensive tobacco control policies in South Korea reduced smoking prevalence among males, initially among older men and later among both older men and younger men.

Development of a magnetic Single Cell Micro Array

Experiments using single cells are valuable for revealing individual cell behaviour, which is of interest to many biomedical researchers. In such experiments, various types of devices capable of aligning cells into organized arrays are often used. In this paper, we present a novel Single Cell Micro Array device that makes use of magnetic forces. Prototypes of this device have been fabricated, and successfully tested using Jurkat cells that have been labelled with nano-magnetic particles. Experimental results show that the prototypes are effective on capturing and placing the labelled cells in an array.

Design of a continuous passive and active motion device for hand rehabilitation

This paper presents the design of a novel, portable device for hand rehabilitation. The device provides for CPM (continuous passive motion) and CAM (continuous active motion) hand rehabilitation for patients recovering from damage such as flexor tendon repair and strokes. The device is capable of flexing/extending the MCP (metacarpophalangeal) and PIP (proximal interphalangeal) joints through a range of motion of 0 degrees to 90 degrees for both the joints independently. In this way, typical hand rehabilitation motions such as intrinsic plus, intrinsic minus, and a fist can be achieved without the need of any splints or attachments. The CPM mode is broken into two subgroups. The first mode is the use of preset waypoints for the device to cycle through. The second mode involves motion from a starting position to a final position, but senses the torque from the user during the cycle. Therefore the user can control the ROM by resisting when they are at the end of the desired motion. During the CPM modes the device utilizes a minimum jerk trajectory model under PD control, moving smoothly and accurately between preselected positions. CAM is the final mode where the device will actively resist the movement of the user. The user moves from a start to end position while the device produces a torque to resist the motion. This active resistance motion is a unique ability designed to mimic the benefits of a human therapist. Another unique feature of the device is its ability to independently act on both the MCP and PIP joints. The feedback sensing built into the device makes it capable of offering a wide and flexible range of rehabilitation programs for the hand.

A feasibility study for measuring accurate tendon displacements using an audio-based Fourier analysis of pulsed-wave Doppler ultrasound signals

The accuracy of Pulsed-Wave Doppler Ultrasound displacement measurements of a slow moving "tendon-like" string was investigated in this study. This was accomplished by estimating string displacements using an audio-based Fourier analysis of a Pulsed-Wave Doppler signal from a commercial ultrasound scanner. Our feasibility study showed that the proposed technique is much more accurate at estimating the actual string displacement in comparison to the scanner's onboard software. Furthermore, this study also shows that a real-time Doppler data acquisition from an ultrasound scanner is possible for the ultimate purpose of real-time biological tendon displacement monitoring.

In vitrometabolism of eupatilin by multiple cytochrome P450 and UDP-glucuronosyltransferase enzymes

Eupatilin, a pharmacologically active flavone derived from Artemisia plants, is extensively metabolized to eupatilin glucuronide, 4-O-desmethyleupatilin and 4-O-desmethyleupatilin glucuronide in human liver microsomes. This study characterized the human liver cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT) enzymes responsible for the metabolism of eupatilin. The specific CYPs responsible for O-demethylation of eupatilin to the major metabolite, 4-O-desmethyleupatilin were identified using a combination of correlation analysis, immuno-inhibition, chemical inhibition in human liver microsomes and metabolism by human cDNA-expressed CYP enzymes. UGT enzymes involved in the eupatilin glucuronidation were identified using pooled human liver microsomes and human cDNA-expressed UGT enzymes. Eupatilin was predominantly metabolized by CYP1A2 and, to a lesser extent, CYP2C8 mediated O-demethylation of eupatilin to 4-O-desmethyleupatilin. Eupatilin glucuronidation was catalysed by UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9, and UGT1A10.

Effect of electrolyzed water for reduction of foodborne pathogens on lettuce and spinach

The ability of electrolyzed water (EW) to inactivate foodborne pathogens on the surfaces of lettuce and spinach was investigated. Lettuce and spinach leaves were inoculated with a cocktail of 3 strains each of Escherichia col O157:H7, Salmnonella Typhimurium, and Listeria monocytogenes and treated with acidic electrolyzed water (AC-EW), alkaline electrolyzed water (AK-EW), alkaline electrolyzed water followed by acidic electrolyzed water (sequential treatment, AK-EW + AC-EW), deionized water followed by acidic electrolyzed water (sequential treatment, DW + AC-EW), and deionized water (control, DW) for 15, 30 s, and 1, 3, and 5 min at room temperature (22 +/- 2 degrees C). For all 3 pathogens, the same pattern of microbial reduction on lettuce and spinach were apparent. The relative efficacy of reduction was AC-EW > DW + AC-EW approximately = AK-EW + AC-EW > AK-EW > control. After a 3-min treatment of AC-EW, the 3 tested pathogens were reduced below the detection limit (0.7 log). DW + AC-EW and AK-EW + AC-EW produced the same levels of reduction after 5 min when compared to the control. AK-EW did not reduce levels of pathogens even after a 5-min treatment on lettuce and spinach. Results suggest that AC-EW treatment was able to significantly reduce populations of the 3 tested pathogens from the surfaces of lettuce and spinach with increasing time of exposure.

Ultrasound mediated transdermal insulin delivery in pigs using a lightweight transducer

PURPOSE

In previous studies, ultrasound mediated transdermal drug delivery has shown a promising potential as a method for noninvasive drug administration. For prospective future human application, this study was designed to determine the feasibility of lightweight cymbal transducer array as a practical device for noninvasive transdermal insulin delivery in large pigs.

MATERIALS AND METHODS

Six Yorkshire pigs (100-140 lbs) were divided into two groups. As the control (n = 3), the first group did not receive any ultrasound exposure with the insulin. The second group (n = 3) was treated with ultrasound and insulin at 20 kHz with an I(sptp) = 100 mW/cm(2) at a 20% duty cycle for 60 min. With the pigs in lateral recumbency after anesthesia, the ultrasound transducer with insulin was placed on the axillary area of the pig. At the beginning and every 15 min up to 90 min, the blood glucose level was determined using a glucose monitoring system. To compare the results of individual animals, the change of blood glucose level was normalized to each animal's initial glucose value at the start of the experiment.

RESULTS

Although each animal had a different initial glucose level, the mean and standard error for the six animals was 146 +/- 13 mg/dl. For the control group, the blood glucose level increased to 31 +/- 21 mg/dl compared to the initial baseline over the 90 min experiment. However for the ultrasound with insulin treated group, the glucose level decreased to -72 +/- 5 mg/dl at 60 min (p < 0.05) and continued to decrease to -91 +/- 23 mg/dl in 90 min (p < 0.05).

CONCLUSION

The results indicate the feasibility of ultrasound mediated transdermal insulin delivery using the cymbal transducer array in animal with a similar size and weight to a human. Based on these result, the cymbal array has potential as a practical ultrasound system for noninvasive transdermal insulin delivery for diabetes management.

Antibacterial and antifungal activity of pinosylvin, a constituent of pine

The antibacterial and antifungal activities of pinosylvin (3,5-dihydroxy-trans-stilbene), a constituent of pine, were studied and compared with those of resveratrol (3,5,4'-trihydroxy-trans-stilbene). Pinosylvin exhibited more potent growth inhibitory activity against Candida albicans and Saccharomyces cerevisiae.

Naringin supplementation lowers plasma lipids and enhances erythrocyte antioxidant enzyme activities in hypercholesterolemic subjects

BACKGROUND AND AIMS

Preliminary studies have shown that naringin has a potent lipid-lowering effect and antioxidant capacity in high-cholesterol diet fed animals. Accordingly, the present study was conducted to investigate the effect of naringin on hypercholesterolemic subjects.

METHODS

A hypercholesterolemic group (n=30) and healthy control group (n=30) were established based on the plasma cholesterol levels in the subjects, then all subjects received naringin (400mg/capsule/day) with regular meals for a period of 8 weeks.

RESULTS

In the hypercholesterolemic subjects, naringin supplementation was found to lower the plasma total cholesterol by 14% and low-density lipoprotein cholesterol concentrations by 17%, while the plasma triglyceride and high-density lipoprotein cholesterol concentrations remained unaffected. The apolipoprotein B levels in the hypercholesterolemic subjects were significantly lowered after naringin treatment, yet no change was observed in the apolipoprotein A-1 levels. The erythrocyte superoxide dismutase and catalase activities in the hypercholesterolemic group were significantly increased, whereas the glutathione peroxidase activity and plasma TBARS levels were not different from the baseline measurements. Meanwhile, naringin supplementation had no affect on plasma lipids, apolipoproteins, and TBARS levels or antioxidant enzyme activities in the control group.

CONCLUSIONS

Therefore, these data suggest that naringin may play an important role in lowering plasma cholesterol and regulating the antioxidant capacity in hypercholesterolemic subjects.

Hepatoprotective and free radical scavenging effects of Nelumbo nucifera

Ethanol extracts from Nelumbo nucifera (ENN) seeds were studied for possible antioxidative and hepatoprotective effects. Antioxidative effects were measured spectrophotometrically by reduction of 2,2'-Diphenyl-1-picrylhydrazyl (DPPH) radicals. Hepatoprotective effects were tested using carbon tetrachloride (CCl4) and aflatoxin B1 (AFB1)-induced hepatocyte toxicity models. ENN showed potent free radical scavenging effects with a median inhibition concentration of 6.49 microg/ml. Treatment of hepatocytes with ENN inhibited both the production of serum enzymes and cytotoxicity by CCl4. The genotoxic and cytotoxic effects of AFB1 were also inhibited by ENN in dose-dependent manners. These hepatoprotective effects of ENN against CCl4 and AFB1 might result from its potent antioxidative properties.

Antibacterial, antitumor and hemolytic activities of alpha-helical antibiotic peptide, P18 and its analogs

The alpha-helical antibiotic peptide (P18: KWKLFKKIPKFLHLAKKF-NH2) designed from the cecropin A(1-8)-magainin 2 (1-12) hybrid displayed strong bactericidal and tumoricidal activity without inducing hemolysis. The effect of the Pro9 residue at central position of P18 on cell selectivity was investigated by Pro9 --> Leu or Pro9 --> Ser substitution. Either substitution markedly reduced the antibacterial activity of P18 and increased hemolysis, although it did not significantly affect cytotoxicity against human transformed tumor and normal fibroblast cells. These results suggest that a proline kink in alpha-helical antibiotic peptide P18 serves as a hinge region to facilitate ion channel formation on bacterial cell membranes and thus plays an important role in providing high selectivity against bacterial cells. Furthermore, to investigate the structure-antibiotic activity relationships of P18, a series of N- or C-terminal deletion and substitution analogs of P18 were synthesized. The C-terminal region of P18 was related to its antibiotic activity and alpha-helical conformation on lipid membranes rather than N-terminal one. Higher alpha-helicity of the peptides was involved in the hemolytic and antitumor activity rather than antibacterial activity. Except for [L9]-P18 and [S9]-P18, all the designed peptides containing a Pro residue showed potent antibacterial activity, although they did not induce a cytolytic effect against human erythrocyte and normal fibroblast cells at the concentration required to kill bacteria. In particular, P18 and some analogs (N-1, N-2, N-3, N-3L and N-4L) with potent bactericidal and tumoricidal activity and little or no normal cell toxicity may serve as an attractive candidate for the development of novel anti-infective or antitumor agents.

Inhibitory effect of immunoglobulin E production by jin-deuk-chal (Siegesbeckia orientalis)

Elevated levels of immunoglobulin (Ig) E are associated with immediate-type allergic reactions. Jin-deuk-chal is the whole plant of Siegesbeckia orientalis (SO) sL Immunization of mice with small amounts of protein antigens on alum results in several fold increases in total plasma IgE, much of it specific for the immunizing antigen. In the present study, we investigated the effect of Siegesbeckia orientalis (SO) on IgE production. SO inhibited the plasma levels of IgE induced by antigens. The effects of SO on the interleukin (IL)-4-dependent IgE response by mouse whole spleen cells were studied. IL-4 dependent IgE production of lipopolysaccharide (LPS)-stimulated whole spleen cells was inhibited by SO. In addition, using U266B I human IgE-bearing B cells, we found that SO inhibited the production of IgE activated by LPS plus IL-4. These results suggest that SO have antiallergic activity by inhibition of IgE production from B cells.

Effect of allergina on mast cell-mediated allergic reactions

The herbal formulation ALLERGINA has been used against allergic inflammation disease for generations, and still occupies an important place in traditional medicine in Korea. In this study, we investigated the effect of ALLERGINA by oral administration in mast cell-mediated anaphylaxis responses. ALLERGINA dose-dependently inhibited compound 48/48-induced systemic anaphylaxis with doses of 10(-2) to 5 g/kg 1 h before orally administered. Of special note, ALLERGINA inhibited systemic anaphylaxis completely with doses of 1 g/kg and 5 g/kg. ALLERGINA (1 g/kg) also inhibited passive cutaneous anaphylaxis by 84%. ALLERGINA dose-dependently inhibited histamine release from rat peritoneal mast cells. When ALLERGINA (0.01 mg/ ml) was added, ALLERGINA inhibited the production of tumor necrosis factor-alpha and interleukin-6, 80% and 26%, respectively in anti-dinitrophenyl IgE antibody-stimulated mast cells. Our studies provide evidence that ALLERGINA may be beneficial in the treatment of allergic inflammation diseases.

Inhibitory effect on immunoglobulin E production in vivo and in vitro by Siegesbeckia glabrescens

Elevated levels of immunoglobulin (Ig)E are associated with immediate-type allergic reactions. The effect of an aqueous extract of Siegesbeckia glabrescens (Compositae) whole plants (SGWP) on in vivo and in vitro IgE production was studied in mice. SGWP dose-dependently inhibited the active systemic anaphylaxis and serum IgE production induced by immunization with ovalbumin and Bordetella pertussis toxin absorbed to aluminium hydroxide gel. SGWP dose-dependently inhibited IL-4-dependent IgE production by lipopolysaccharide-stimulated murine whole spleen cells. In the case of U266 human IgE-bearing B cells, SGWP also showed an inhibitory effect on IgE production. These results suggest that SGWP has an anti-allergic activity by inhibiting IgE production from B cells.

Platelet concentration and its effect on bone formation in calvarial defects: an experimental study in rabbits

STATEMENT OF PROBLEM

The use of the platelet concentration technique is widespread in dental implant surgery. However, its effect or mechanism is not clearly understood.

PURPOSE

This study introduced an animal model for the platelet concentration technique and evaluated its effect on bone formation with natural cancellous bovine bone mineral.

MATERIAL AND METHODS

Adult New Zealand white rabbits were used as the animal model. A density gradient medium was used to obtain a constant platelet count for the preparation of platelet concentrates. In the experimental group, natural cancellous bovine bone mineral with added platelet concentrates was grafted onto critically sized bony defects of the rabbit calvarium. Bone formation in the tissue sections was evaluated with soft x-ray imaging and computer tomography.

RESULTS

The average platelet count of the rabbit platelet concentrates was 1487 x 10(3)/microL (287% concentrated). In all the tested parameters, greater bone densities were obtained in grafts that were combined with platelet concentrates.

CONCLUSION

This study showed that the rabbit is a useful animal model for studying the platelet concentration technique. When combined with grafts of natural cancellous bovine bone mineral, the technique increased bone formation.

Constituents of Eugenia sandwicensis with potential cancer chemopreventive activity

A triterpenoid, 3beta-cis-p-coumaroyloxy-2alpha,23-dihydroxyolean-12-en-28-oic acid (1), and two natural products, 3beta-trans-p-coumaroyloxy-2alpha,23-dihydroxyolean-12-en-28-oic acid (2) and 23-trans-p-coumaroyloxy-2alpha,3beta-dihydroxyolean-12-en-28-oic acid (3), were isolated from a chloroform-soluble extract of the stems of Eugenia sandwicensis, along with 10 known compounds. Of these compounds, 2 showed significant inhibitory activity (79.2% at 4 microg/ml) in a 7,12-dimethylbenz[a]anthracene-induced mouse mammary organ culture assay system of relevance to cancer chemoprevention. Gallic acid was isolated as an antioxidative constituent of an ethyl acetate-soluble extract of E. sandwicensis stems. Isolates 1-3 were characterized on the basis of spectral and chemical evidence.

Detection of West Nile virus in mosquitoes by RT-PCR

A reverse transcriptase-polymerase chain reaction (RT-PCR) assay employing <<TaqMan>> detection technology was developed to identify West Nile virus in experimentally infected mosquitoes. The specificity of the assay was evaluated with the following viruses: eastern equine encephalitis, Ilheus, West Nile and yellow fever viruses. The limits of detection were determined using West Nile viral RNA extracted from serial dilutions of virus culture in infected mosquitoes. Limit of detection was 5 PFU from extracted mosquitoes. We were able to detect the presence of one infected mosquito in a pool of 50 repeatedly. When the RT-PCR was used with coded samples of intrathoracically-infected and uninfected mosquitoes, the assay detected the virus in all infected mosquitoes. Analytic sensitivity and specificity were 100%. This assay offers an efficient and rapid method of identifying West Nile virus in infected mosquitoes or cell culture.

Antifibrotic effect of extracellular biopolymer from submerged mycelial cultures of Cordyceps militaris on liver fibrosis induced by bile duct ligation and scission in rats

The antifibrotic effects of hot water extract (WEC), intracellular biopolymer (IPC) and extracellular biopolymers (EPC) from mycelial liquid culture of Cordyceps militaris on liver fibrosis were studied. Liver fibrosis was induced by a bile duct ligation and scission (BDL/S) operation, duration of 4 weeks in rats. In BDL/S rats, the levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total bilirubin in serum and hydroxyproline content in liver were dramatically increased. The WEC or IPC treatment (30 mg/kg/day for 4 weeks, p.o.) in BDL/S rats reduced the serum AST, ALT and ALP levels significantly (p<0.01). The EPC treatment (30 mg/kg/day for 4 weeks, p.o.) reduced the serum ALT, AST and ALP levels significantly (p<0.01). Malondialdehyde contents in liver treated with WEC, IPC or EPC were significantly reduced (p<0.05). But Liver hydroxyproline content was decreased only in EPC treated BDL/S rats to 55% that of BDL/S control rats (p<0.01). The morphological characteristics and expression of alpha smooth muscle like actin in fibrotic liver, which appeared in BDL/S control group were improved in EPC treated fibrotic liver. These results indicate that EPC (30 mg/kg/day for 4 weeks, p.o.) has an antifibrotic effect on fibrotic rats induced by BDL/S.

Structure-activity analysis of SMAP-29, a sheep leukocytes-derived antimicrobial peptide

SAMP-29 is a cathelecidin-derived antimicrobial peptide deduced from sheep myeloid mRNA. To elucidate the structural-activity relationship of SMAP-29, several analogues were synthesized and their antibiotic activity was investigated. Compared to parental SMAP-29, SMAP-29(1-17) and [K(22,25,27)]-SMAP-29 retained relatively effective antimicrobial activity (MIC: 1.0-8.0 microM), but resulted in a complete loss of hemolytic activity. Pro-19 --> Ala substitution ([A19]-SMAP-29) in SMAP-29 induced a significant reduction in antibacterial activity. These results suggested that the N-terminal amphipathic alpha-helical region and the C-terminal hydrophobic region of SMAP-29 are responsible for antimicrobial activity and hemolytic activity, respectively, and the central Pro-19 in SMAP-29 plays a critical role in showing improved antibacterial activity. In particular, [K(2,7,13)]-SMAP-29(1-17) showed potent antimicrobial activity under high salt conditions without hemolytic activity. Thus, this short peptide could serve as an attractive candidate for the development of therapeutic antimicrobial drugs. Structural analysis by circular dichroism suggested that SMAP-29 seems to adopt a helix-bend/turn-extended random conformation.

SMRTE inhibits MEF2C transcriptional activation by targeting HDAC4 and 5 to nuclear domains

The silencing mediator for retinoic acid and thyroid hormone receptors (SMRT) mediates transcriptional repression by recruiting histone deacetylases (HDACs) to the DNA-bound nuclear receptor complex. The full-length SMRT (SMRTe) contains an N-terminal sequence that is highly conserved to the nuclear receptor corepressor N-CoR. To date, little is known about the activity and function of the full-length SMRTe protein, despite extensive studies on separated receptor interaction and transcriptional repression domains. Here we show that SMRTe inhibits MEF2C transcriptional activation by targeting selective HDACs to unique subnuclear domains. Indirect immunofluorescence studies with anti-SMRTe antibody reveal discrete cytoplasmic and nuclear speckles, which contain RARalpha in an RA-sensitive manner. Formation of the SMRTe nuclear speckles results in recruitment of several class I and class II HDACs to these subnuclear domains in a process depending on HDAC enzymatic activity. Intriguingly, although HDAC4 is located primarily in the cytoplasm, coexpression of SMRTe dramatically translocates HDAC4 from the cytoplasm into the nucleus, where HDAC4 prevents MEF2C from activating muscle differentiation. SMRTe also translocates HDAC5 from diffusive nucleoplasm into discrete nuclear domains. Accordingly, SMRTe synergizes with HDAC4 and 5 to inhibit MEF2C transactivation of target promoter, suggesting that nuclear domain targeting of HDAC4/5 may be important in preventing muscle cell differentiation. These results highlight an unexpected new function of the nuclear receptor corepressor SMRTe for its role in regulating cellular trafficking of nuclear receptor and selective HDACs that may play an important role in regulation of cell growth and differentiation.

Lipopolysaccharide inhibits induction of long-term potentiation and depression in the rat hippocampal CA1 area

We examined the effects of lipopolysaccharide, a bacterial endotoxin, on synaptic plasticity in the rat hippocampal CA1 area in vitro. Lipopolysaccharide suppressed the induction of long-term potentiation elicited by tetanic stimulation and long-term depression, elicited by low-frequency stimulation of Schaffer collateral-commissural fibres at 10 and 50 microg/ml, respectively. Lipid A (1 microg/ml), the biologically active component of lipopolysaccharide, mimicked the effects of 10 microg/ml lipopolysaccharide on long-term potentiation and depression. Nifedipine, an L-type voltage-sensitive Ca(2+) channel antagonist, did not influence the induction of long-term potentiation and depression, whereas a high concentration of extracellular calcium enabled long-term potentiation induction in the presence of 10 microg/ml lipopolysaccharide. The NMDA receptor antagonist D,L-2-amino-5-phosphonovaleric acid (APV, 50 microM), nifedipine (10 microM) or lipopolysaccharide (10 or 50 microg/ml) partially reduced the magnitude of tetraethylammonium-induced long-term potentiation. Nifedipine combined with lipopolysaccharide completely blocked tetraethylammonium-induced long-term potentiation. Whole-cell voltage clamp recordings showed that lipopolysaccharide suppressed NMDA receptor-mediated excitatory postsynaptic currents (EPSCs). Our results indicate that lipopolysaccharide acutely modifies synaptic plasticity by blocking Ca(2+) entry through NMDA receptors, suggesting a possible mechanism for the amnesic action of bacterial infection.