Pannexin 1 Modulates Angiogenic Activities of Human Endothelial Colony-Forming Cells Through IGF-1 Mechanism and Is a Marker of Senescence

BACKGROUND

We examined the role of Panxs (pannexins) in human endothelial progenitor cell (EPC) senescence.

METHODS

Young and replication-induced senescent endothelial colony-forming cells (ECFCs) derived from human circulating EPCs were used to examine cellular activities and senescence-associated indicators after transfection of short interference RNA specific to Panx1 or lentivirus-mediated Panx1 overexpression. Hind limb ischemia mice were used as in vivo angiogenesis model. Protein and phospho-kinase arrays were used to determine underlying mechanisms.

RESULTS

Panx1 was the predominant Panx isoform in human ECFCs and upregulated in both replication-induced senescent ECFCs and circulating EPCs from aged mice and humans. Cellular activities of the young ECFCs were enhanced by Panx1 downregulation but attenuated by its upregulation. In addition, reduction of Panx1 in the senescent ECFCs could rejuvenate cellular activities with reduced senescence-associated indicators, including senescence-associated β-galactosidase activity, p16INK4a (cyclin-dependent kinase inhibitor 2A), p21 (cyclin-dependent kinase inhibitor 1), acetyl-p53 (tumor protein P53), and phospho-histone H2A.X (histone family member X). In mouse ischemic hind limbs injected senescent ECFCs, blood perfusion ratio, salvaged limb outcome, and capillary density were all improved by Panx1 knockdown. IGF-1 (insulin-like growth factor 1) was significantly increased in the supernatant from senescent ECFCs after Panx1 knockdown. The enhanced activities and paracrine effects of Panx1 knockdown senescent ECFCs were completely inhibited by anti-IGF-1 antibodies. FAK (focal adhesion kinase), ERK (extracellular signal-regulated kinase), and STAT3 (signal transducer and activator of transcription 3) were activated in senescent ECFCs with Panx1 knockdown, in which the intracellular calcium level was reduced, and the activation was inhibited by supplemented calcium. The increased IGF-1 in Panx1-knockdown ECFCs was abrogated, respectively, by inhibitors of FAK (PF562271), ERK (U0126), and STAT3 (NSC74859) and supplemented calcium.

CONCLUSIONS

Panx1 expression is upregulated in human ECFCs/EPCs with replication-induced senescence and during aging. Angiogenic potential of senescent ECFCs is improved by Panx1 reduction through increased IGF-1 production via activation of the FAK-ERK axis following calcium influx reduction. Our findings provide new strategies to evaluate EPC activities and rejuvenate senescent EPCs for therapeutic angiogenesis.

Immunologic Heterogeneity in 2 Cartilage-Hair Hypoplasia Patients With a Distinct Clinical Course

BACKGROUND AND OBJECTIVE

Cartilage-hair hypoplasia (CHH) syndrome is a rare autosomal recessive syndrome associated with skeletal dysplasia, varying degrees of combined immunodeficiency (CID), short stature, hair hypoplasia, macrocytic anemia, increased risk of malignancies, and Hirschsprung disease. To provide clinical and immunological insights obtained from 2 unrelated patients who displayed clinical characteristics of CHH.

METHODS

Two patients with suspected CHH syndrome due to skeletal dysplasia and immunodeficiency underwent an immunological and genetic work-up using flow cytometry, next-generation sequencing (NGS) of the immune repertoire, and Sanger sequencing to identify the underlying defects.

RESULTS

Patient 1 presented with low birth weight and skeletal dysplasia. Newborn screening was suggestive of T-cell immunodeficiency, as T-cell receptor excision circle levels were undetectable. Both the T-cell receptor (TCR) Vß and TCR-g (TRG) repertoires were restricted, with evidence of clonal expansion. Genetic analysis identified compound heterozygous RMRP variants inherited from both parents. Patient 2 presented with recurrent lung and gastrointestinal infections, skeletal dysplasia, failure to thrive, and hepatomegaly. The polyclonal pattern of the TCRß repertoire was normal, with only slight overexpression of TCR-ßV20 and restricted expression of Vßs. TRG expressed a normal diverse repertoire, similar to that of the healthy control sample. Genetic analysis identified biallelic novel regulatory variants in RMRP. Both parents are carriers of this mutation.

CONCLUSION

Our findings demonstrate how the immunological work-up, supported by genetic findings, can dramatically change treatment and future outcome in patients with the same clinical syndrome.

Hsa-miR-409-3p regulates endothelial progenitor senescence via PP2A-P38 and is a potential ageing marker in humans

We explored the roles of hsa-microRNA (miR)-409-3p in senescence and signalling mechanism of human endothelial progenitor cells (EPCs). Hsa-miR-409-3p was found upregulated in senescent EPCs. Overexpression of miRNA mimics in young EPCs inhibited angiogenesis. In senescent EPCs, compared to young EPCs, protein phosphatase 2A (PP2A) was downregulated, with activation of p38/JNK by phosphorylation. Young EPCs treated with siPP2A caused inhibited angiogenesis with activation of p38/JNK, similar to findings in senescent EPCs. Time series analysis showed, in young EPCs treated with hsa-miR-409-3p mimics, PP2A was steadily downregulated for 72 h, while p38/JNK was activated with a peak at 48 hours. The inhibited angiogenesis of young EPCs after miRNA-409-3p mimics treatment was reversed by the p38 inhibitor. The effect of hsa-miR-409-3p on PP2A signalling was attenuated by exogenous VEGF. Analysis of human peripheral blood mononuclear cells (PBMCs) obtained from healthy people revealed hsa-miR-409-3p expression was higher in those older than 65 years, compared to those younger than 30 years, regardless of gender. In summary, hsa-miR-409-3p was upregulated in senescent EPCs and acted as a negative modulator of angiogenesis via targeting protein phosphatase 2 catalytic subunit alpha (PPP2CA) gene and regulating PP2A/p38 signalling. Data from human PBMCs suggested hsa-miR-409-3p a potential biomarker for human ageing.

AD-9308 ameliorates the impacts of 4-HNE on the progress of pulmonary arterial hypertension in aldehyde dehydrogenase 2*1*2 knock-in mice

 

Endothelial dysfunctions play a critical role on the development of pulmonary arterial hypertension (PAH). It has been reported that the one-year mortality rate is still up to 15% even with PAH-targeted therapy, implying that there may be untargeted pathways. 4-hydroxynenonal (4-HNE), an unsaturated aldehyde, is highly induced in the lungs of PAH animals and its serum levels were also reported to be higher in PAH patients. 4-HNE is metabolized by mitochondrial aldehyde dehydrogenase (ALDH2), which is dysfunctional in near 40% of East Asian people. Currently, the impacts of 4-HNE on endothelial dysfunctions in the development of PAH are unclear. In terms of translational medicine, we proposed that modulation of 4-HNE level may alleviate the progress of PAH patients with ALDH2 deficiency.

We found that 4-HNE alone was not sufficient to induce pulmonary artery endothelial cell (PAEC) functional changes, including proliferation, migration and tube formation, whereas their effects emerge from the depletion of ALDH2. We further mimicked human ALDH2 functional deficiency by using daidzin (DZN), an inhibitor which is able to block the substrate binding site of ALDH2. ALDH2 functional inhibition alone did not induce any PAEC functional change, while an add-on of 4-HNE impaired PAEC functions. In addition, 4-HNE significantly reduced eNOS activity with combined DZN treatment. Consistent with the mechanism of ALDH2 activity-mediated angiogensis, ALDH2 enhancers Alda-1 and AD-5591 completely reverse the anti-angiogenic effects of 4-HNE in the presence of DZN. To further confirm whether ALDH2 functional deficiency impact on PAH development in mammals, heterozygous ALDH2*1/*2 transgenic and wild-type mice were subjected to chronic hypoxia to induce PAH. ALDH2*1/*2 transgenic mice had similar right ventricular systolic pressure (RVSP) as wild-type mice. However, after exposure to chronic hypoxia, ALDH2*1/*2 transgenic mice indeed developed a significantly higher RVSP than that in wild-type mice. Furthermore, we demonstrated that 4-HNE expression was profoundly enhanced in ALDH2*1/*2 transgenic mice by chronic hypoxia-induced PAH with pulmonary artery smooth muscle cell hyperplasia. More importantly, we found that AD-9308, an enhancer of ALDH2 significantly decreased hypoxia-induced RVSP elevation in heterozygous ALDH2*1/*2 transgenic mice.

Taken together, our data demonstrate that 4-HNE and ALDH2 functional deficiency potentially contribute to PAH development and worsening, and that ALDH2 enhancers may be promising as a PAH adjunct therapy, particularly for patients with ALDH2 nonfunctional alleles.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Science and Technology, Taiwan

Deferoxamine accelerates endothelial progenitor cell senescence and compromises angiogenesis

Senescence reduces the circulating number and angiogenic activity of endothelial progenitor cells (EPCs), and is associated with aging-related vascular diseases. However, it is very time-consuming to obtain aged cells (~1 month of repeated replication) or animals (~2 years) for senescence studies. Here, we established an accelerated senescence model by treating EPCs with deferoxamine (DFO), an FDA-approved iron chelator. Four days of low-dose (3 μM) DFO induced senescent phenotypes in EPCs, including a senescent pattern of protein expression, impaired mitochondrial bioenergetics, altered mitochondrial protein levels and compromised angiogenic activity. DFO-treated early EPCs from young and old donors (< 35 vs. > 70 years old) displayed similar senescent phenotypes, including elevated senescence-associated β-galactosidase activity and reduced relative telomere lengths, colony-forming units and adenosine triphosphate levels. To validate this accelerated senescence model in vivo, we intraperitoneally injected Sprague-Dawley rats with DFO for 4 weeks. Early EPCs from DFO-treated rats displayed profoundly senescent phenotypes compared to those from control rats. Additionally, in hind-limb ischemic mice, DFO pretreatment compromised EPC angiogenesis by reducing both blood perfusion and capillary density. DFO thus accelerates EPC senescence and appears to hasten model development for cellular senescence studies.

Ultrasonic microbubble VEGF gene delivery improves angiogenesis of senescent endothelial progenitor cells

The therapeutic effects of ultrasonic microbubble transfection (UMT)-based vascular endothelial growth factor 165 (VEGF165) gene delivery on young and senescent endothelial progenitor cells (EPCs) were investigated. By UMT, plasmid DNA (pDNA) can be delivered into both young EPCs and senescent EPCs. In the UMT groups, higher pDNA-derived protein expression was found in senescent EPCs than in young EPCs. Consistent with this finding, a higher intracellular level of pDNA copy number was detected in senescent EPCs, with a peak at the 2-h time point post UMT. Ultrasonic microbubble delivery with or without VEGF improved the angiogenic properties, including the proliferation and/or migration activities, of senescent EPCs. Supernatants from young and senescent EPCs subjected to UMT-mediated VEGF transfection enhanced the proliferation and migration of human aortic endothelial cells (HAECs), and the supernatant of senescent EPCs enhanced proliferation more strongly than the supernatant from young EPCs. In the UMT groups, the stronger enhancing effect of the supernatant from senescent cells on HAEC proliferation was consistent with the higher intracellular VEGF pDNA copy number and level of protein production per cell in the supernatant from senescent cells in comparison to the supernatant from young EPCs. Given that limitations for cell therapies are the inadequate number of transplanted cells and/or insufficient cell angiogenesis, these findings provide a foundation for enhancing the therapeutic angiogenic effect of cell therapy with senescent EPCs in ischaemic cardiovascular diseases.

Enhanced Proliferation of Endothelial Progenitor Cells Post-Ultrasonic Microbubble Transfection Is Plasmid DNA Size Dependent and Contributed by Interleukin-6 Generation

We investigated whether ultrasonic microbubble transfection (UMT) would enhance the transfection of large-sized luciferase plasmids (5.6, 9.2 and 33 kb) and biological impacts. Porcine venous blood endothelial progenitor cells (EPCs) were cultured in a medium containing plasmid DNA (pDNA) of different sizes followed by UMT and functional assays. Real-time polymerase chain reaction was conducted to investigate the effects of transfection of pDNA on multiple molecules central to endothelial function. The results indicated enhanced luciferase expression after UMT but the enhancement declined with increase in the size of the plasmid. UMT of pDNAs sized 5.6 and 9.2 kb into EPCs led to significant enhancement of proliferation. The interleukin-6 (IL-6) secreted from UMT of EPCs also increased in the 5.6- and 9.2-kb pDNA groups. Treatment of the transfected EPCs with anti-IL-6 antibody neutralized the proliferation. In conclusion, UMT of pDNAs sized 5.6 and 9.2 kb into EPCs increased the secretion of IL-6, which in turn enhanced cell proliferation.

KC21 Peptide Inhibits Angiogenesis and Attenuates Hypoxia-Induced Retinopathy

Desmogleins (Dsg2) are the major components of desmosomes. Dsg2 has five extracellular tandem cadherin domains (EC1-EC5) for cell-cell interaction. We had previously confirmed the Dsg2 antibody and its epitope (named KC21) derived from EC2 domain suppressing epithelial-mesenchymal transition and invasion in human cancer cell lines. Here, we screened six peptide fragments derived from EC2 domain and found that KR20, the parental peptide of KC21, was the most potent one on suppressing endothelial colony-forming cell (ECFC) tube-like structure formation. KC21 peptide also attenuated migration but did not disrupt viability and proliferation of ECFCs, consistent with the function to inhibit VEGF-mediated activation of p38 MAPK but not AKT and ERK. Animal studies showed that KC21 peptides suppressed capillary growth in Matrigel implant assay and inhibited oxygen-induced retinal neovascularization. The effects were comparable to bevacizumab (Bev). In conclusion, KC21 peptide is an angiogenic inhibitor potentially useful for treating angiogenesis-related diseases.

Common Genetic Variants on Bone Morphogenetic Protein Receptor Type IB (BMPR1B) Gene Are Predictive for Carotid Intima-Media Thickness

BACKGROUND

Bone morphogenetic proteins (BMP) 2 and 4 are implicated in the development of atherosclerosis. However, the relationships between the proteins, their main receptors and carotid intima-media thickness (cIMT), a predictive preclinical phenotype of atherosclerosis, have not been established. Methods and Results: We screened and validated the relationships of single-nucleotide polymorphisms (SNPs) on BMP2, BMP4, BMPR1A, BMPR1B, and BMPR2 with thicker cIMT by 2 independent case-control studies that used different subject selection methods. Among 200 screened SNPs, 12 on BMPR1B were regarded as candidate genetic markers (P-value <5.0×10^-4). After combining the discovery and validation studies and adjusting for traditional cardiovascular risk factors, rs4456963*G, rs4235438*T, rs2522530*T, and rs3796433*C showed significant higher odds ratios (ORs) of having thicker cIMT (adjusted ORs: 1.50-1.56; all P-values <2.5×10^-4). Multivariate analyses showed that rs4456963 and rs3796433 were significantly independent determinants of cIMT thickening. The corresponding multivariate-adjusted ORs for rs4456963*G and rs3796433*C alleles were 1.50 (95% confidence interval (CI): 1.22-1.84) and 1.50 (95% CI: 1.23-1.82), respectively. Interaction between rs4456963 and rs3796433 was evident by the significantly higher OR (8.16, 95% CI: 3.12-21.3) for subjects with the GG-CC genotype. The rs4456963*G and rs3796433*C showed positively linear trends with severity of carotid atherosclerosis.

CONCLUSIONS

We identified 2 SNPs on BMPR1B showing significantly independent correlations with thicker cIMT. The study provides invaluable evidence supporting that BMPR1B is closely related to carotid atherosclerosis and a potential target for the development of therapeutic agents for atherosclerotic disease.

Altered T cell receptor beta repertoire patterns in pediatric ulcerative colitis

The antigenic specificity of T cells occurs via generation and rearrangement of different gene segments producing a functional T cell receptor (TCR). High-throughput sequencing (HTS) allows in-depth assessment of TCR repertoire patterns. There are limited data concerning whether TCR repertoires are altered in inflammatory bowel disease. We hypothesized that pediatric ulcerative colitis (UC) patients possess unique TCR repertoires, resulting from clonotypical expansions in the gut. Paired blood and rectal samples were collected from nine newly diagnosed treatment-naive pediatric UC patients and four healthy controls. DNA was isolated to determine the TCR-β repertoire by HTS. Significant clonal expansion was demonstrated in UC patients, with inverse correlation between clinical disease severity and repertoire diversity in the gut. Using different repertoire variables in rectal biopsies, a clear segregation was observed between patients with severe UC, those with mild-moderate disease and healthy controls. Moreover, the overlap between autologous blood-rectal samples in UC patients was significantly higher compared with overlap among controls. Finally, we identified several clonotypes that were shared in either all or the majority of UC patients in the colon. Clonal expansion of TCR-β-expressing T cells among UC patients correlates with disease severity and highlights their involvement in mediating intestinal inflammation.

The hypoparathyroidism-associated mutation in Drosophila Gcm compromises protein stability and glial cell formation

Differentiated neurons and glia are acquired from immature precursors via transcriptional controls exerted by factors such as proteins in the family of Glial Cells Missing (Gcm). Mammalian Gcm proteins mediate neural stem cell induction, placenta and parathyroid development, whereas Drosophila Gcm proteins act as a key switch to determine neuronal and glial cell fates and regulate hemocyte development. The present study reports a hypoparathyroidism-associated mutation R59L that alters Drosophila Gcm (Gcm) protein stability, rendering it unstable, and hyperubiquitinated via the ubiquitin-proteasome system (UPS). Gcm^R59L interacts with the Slimb-based SCF complex and Protein Kinase C (PKC), which possibly plays a role in its phosphorylation, hence altering ubiquitination. Additionally, R59L causes reduced Gcm protein levels in a manner independent of the PEST domain signaling protein turnover. Gcm^R59L proteins bind DNA, functionally activate transcription, and induce glial cells, yet at a less efficient level. Finally, overexpression of either wild-type human Gcmb (hGcmb) or hGcmb carrying the conserved hypoparathyroidism mutation only slightly affects gliogenesis, indicating differential regulatory mechanisms in human and flies. Taken together, these findings demonstrate the significance of this disease-associated mutation in controlling Gcm protein stability via UPS, hence advance our understanding on how glial formation is regulated.

Hearing lessons from flies

Studying the auditory system of the fruit fly can reveal how hearing works in mammals.

Lrrk regulates the dynamic profile of dendritic Golgi outposts through the golgin Lava lamp

Lrrk regulates Golgi outpost (GOP) dynamics in dendrites by antagonizing the interaction between the golgin Lva and dynein heavy chain at GOPs, thereby disrupting minus end–directed transport along dendritic microtubules by dynein.

Constructing the dendritic arbor of neurons requires dynamic movements of Golgi outposts (GOPs), the prominent component in the dendritic secretory pathway. GOPs move toward dendritic ends (anterograde) or cell bodies (retrograde), whereas most of them remain stationary. Here, we show that Leucine-rich repeat kinase (Lrrk), the Drosophila melanogaster homologue of Parkinson’s disease–associated Lrrk2, regulates GOP dynamics in dendrites. Lrrk localized at stationary GOPs in dendrites and suppressed GOP movement. In Lrrk loss-of-function mutants, anterograde movement of GOPs was enhanced, whereas Lrrk overexpression increased the pool size of stationary GOPs. Lrrk interacted with the golgin Lava lamp and inhibited the interaction between Lva and dynein heavy chain, thus disrupting the recruitment of dynein to Golgi membranes. Whereas overexpression of kinase-dead Lrrk caused dominant-negative effects on GOP dynamics, overexpression of the human LRRK2 mutant G2019S with augmented kinase activity promoted retrograde movement. Our study reveals a pathogenic pathway for LRRK2 mutations causing dendrite degeneration.

Direct peroral cholangioscopy using an ultraslim upper endoscope for management of residual stones after mechanical lithotripsy for retained common bile duct stones

BACKGROUND AND STUDY AIMS

The incidence of residual stones after mechanical lithotripsy for retained common bile duct (CBD) stones is relatively high. Peroral cholangioscopy using a mother-baby system may be useful for confirming complete extraction of stones, but has several limitations regarding routine use. We evaluated the role of direct peroral cholangioscopy (DPOC) using an ultraslim upper endoscope for the evaluation and removal of residual CBD stones after mechanical lithotripsy.

PATIENTS AND METHODS

From August 2006 to November 2010, 48 patients who had undergone mechanical lithotripsy for retained CBD stones with no evidence of filling defects in balloon cholangiography were recruited. The bile duct was inspected by DPOC after balloon cholangiography. Detected residual CBD stones were directly retrieved with a basket or balloon catheter under DPOC. The incidence of residual stones detected by DPOC, and the success rate of residual stone retrieval under DPOC were investigated.

RESULTS

DPOC was successfully performed in 46 of the 48 patients (95.8%). Of these, 13 patients (28.3%) had residual CBD stones (mean number 1.4, range 1-3; mean diameter 4.5 mm, range 2.3-9.6). The residual stones were removed directly under DPOC in 11 of these patients (84.6%). There were no complications associated with DPOC or stone removal.

CONCLUSION

DPOC using an ultraslim upper endoscope is a useful endoscopic procedure for the evaluation and extraction of residual stones after mechanical lithotripsy for retained CBD stones.

Anti-influenza virus activity of green tea by-products in vitro and efficacy against influenza virus infection in chickens

Polyphenolic compounds present in green tea, particularly catechins, are known to have strong anti-influenza activity. The goal of this study was to determine whether green tea by-products could function as an alternative to common antivirals in animals compared to original green tea. Inhibition of viral cytopathic effects ascertained by neutral red dye uptake was examined with 50% effective (virus-inhibitory) concentrations (EC₅₀)determined. Against the H1N1 virus A/NWS/33, we found the anti-influenza activity of green tea by-products (EC₅₀ = 6.36 µg/mL) to be equivalent to that of original green tea (EC₅₀= 6.72 µg/mL). The anti-influenza activity of green tea by-products was further examined in mouse and chicken influenza infection models. In mice, oral administration of green tea by-products reduced viral titers in the lungs in the early phase of infection, but they could not protect these animals from disease and death. In contrast, therapeutic administration of green tea by-products via feed or water supplement resulted in a dose-dependent significant antiviral effect in chickens, with a dose of 10 g/kg of feed being the most effective (P < 0.001). We also demonstrated that unidentified hexane-soluble fractions of green tea by-products possessed strong anti-influenza activity, in addition to ethyl acetate-soluble fractions, including catechins. This study revealed green tea by-product extracts to be a promising novel antiviral resource for animals.

Gα13 Signals via p115RhoGEF Cascades Regulating JNK1 and Primitive Endoderm Formation

The heterotrimeric G-protein G(13) mediates the formation of primitive endoderm from mouse P19 embryonal carcinoma cells in response to retinoic acid, signaling to the level of activation of c-Jun N-terminal kinase. The signal linkage map from MEKK1/MEKK4 to MEK1/MKK4 to JNK is obligate in this G alpha(13)-mediated pathway, whereas that between G alpha(13) and MEKKs is not known. The overall pathway to primitive endoderm formation was shown to be inhibited by treatment with Clostridium botulinum C3 exotoxin, a specific inactivator of RhoA family members. Constitutively active G alpha(13) was found to activate RhoA as well as Cdc42 and Rac1 in these cells. Although constitutively active Cdc42, Rac1, and RhoA all can activate JNK1, only the RhoA mutant was able to promote formation of primitive endoderm, mimicking expression of the constitutively activated G alpha(13). Expression of the constitutively active mutant form of p115RhoGEF (guanine nucleotide exchange factor) was found to activate RhoA and JNK1 activities. Expression of the dominant negative p115RhoGEF was able to inhibit activation of both RhoA and JNK1 in response to either retinoic acid or the expression of a constitutively activated mutant of G alpha(13). Expression of the dominant negative mutants of RhoA as well as those of either Cdc42 or Rac1, but not Ras, attenuated G alpha(13)-stimulated as well as retinoic acid-stimulated activation of all three of these small molecular weight GTPases, suggesting complex interrelationships among the three GTPases in this pathway. The formation of primitive endoderm in response to retinoic acid also could be blocked by expression of dominant negative mutants of RhoA, Cdc42, or Rac1. Thus, the signal propagated from G alpha(13) to JNK requires activation of p115RhoGEF cascades, including p115RhoGEF itself, RhoA, Cdc42, and Rac1. In a concerted effort, RhoA in tandem with Cdc42 and Rac1 activates the MEKK1/4, MEK1/MKK4, and JNK cascade, thereby stimulating formation of primitive endoderm.

Down-regulating effect of nicotine on connexin43 gap junctions in human umbilical vein endothelial cells is attenuated by statins

We investigated the effect of nicotine on connexin43 (Cx43) expression and gap-junctional communication in human umbilical vein endothelial cells (HUVEC). We also evaluated whether the effect requires activation of acetyl choline receptors sensitive to nicotine (nAChRs) and is altered by statins. The results showed that expression of Cx43 protein is reduced by nicotine in a dose-dependent manner (6 x 10(-4) M nicotine vs control, 33% reduction, p < 0.01), though Cx43 mRNA is up-regulated (6 x 10(-4) M nicotine vs control, 36% increase, p < 0.01). Concomitantly, the communication function, determined by fluorescence recovery after photobleaching, is decreased (6 x 10(-4) M nicotine vs control, 38% reduction, p < 0.05). Such a down-regulation of Cx43 gap junctions by nicotine disappears in the presence of the nAChRs antagonist, dihydro-beta-erythroidine, and protease inhibitors leupeptin plus N-acetyl-Leu-Leu-Norleu-al (ALLN). Similarly, the effect of nicotine is attenuated by statins, including fluvastatin, lovastatin, pravastatin, and simvastatin, even at the presence of mevalonate. We concluded that i) nicotine down-regulates Cx43 expression and gap-junctional communication in HUVEC via post-transcriptional modification, which involves enhancement of Cx43 proteolysis; ii) the effect of nicotine is mediated via activation of nAChRs; and iii) the effect of nicotine is attenuated by statins through mechanisms outside the hypolipidemic pathway.

Differential expression of connexin43 gap junctions in cardiomyocytes isolated from canine thoracic veins

We investigated the phenotypic features of cardiomyocytes, including the gap junctions, in the myocardial sleeve of thoracic veins. Single cardiomyocytes, isolated from the canine pulmonary veins (PV) and superior vena cava (SVC) using digestive enzymes, were examined by immunoconfocal microscopy using antisera against connexin43 (Cx43), Cx40, and other cell markers. The results showed that isolated cardiomyocytes displayed rod shapes of various sizes, ranging from <50 microm to >200 microm in length, and all the cells expressed alpha-actinin and vinculin. Gap junctions made of various amounts of Cx43 and Cx40 were found at the cell borders. These two connexins were extensively co-localized. Comparison between the thoracic veins showed that cells of the SVC contained more Cx43 gap junctions (total Cx43 gap junctions area per cell surface area, 4.0 +/- 0.2% vs 1.5 +/- 0.2%; p<0.01). In addition, for single-nucleus cells, those from the PV were longer (103.7 +/- 3.6 vs 85.0 +/- 3.1 microm; p<0.01) but narrower (14.4 +/- 0.5 vs 16.9 +/- 0.9 microm; p<0.01). In conclusion, canine thoracic veins contain cardiomyocytes with differences in shape and gap junctions, suggesting that the electrical conduction properties may be different between the thoracic veins.

Short-term temporal variation in PM2.5 mass and chemical composition during the Atlanta Supersite Experiment, 1999

Measurements in urban Atlanta of transient aerosol events in which PM2.5 mass concentrations rapidly rise and fall over a period of 3-6 hr are reported. The data are based on new measurement techniques demonstrated at the U.S. Environmental Protection Agency (EPA) Atlanta Supersite Experiment in August 1999. These independent instruments for aerosol chemical speciation of NO3-, SO4(2-), NH4+, and organic and elemental carbon (OC and EC), reconstructed the observed hourly dry PM2.5 mass to within 20% or better. Data from the experiment indicated that transient PM2.5 events were ubiquitous in Atlanta and were typically characterized by a sudden increase of EC (soot) and OC in the early morning or SO4(2-) in the late afternoon. The frequent temporal decoupling of these events provides insights into their origins, suggesting mobile sources in metro Atlanta as the main contributor to early morning PM2.5 and more regionally located point SO2 sources for afternoon PM2.5 events. The transient events may also have health implications. New data suggest that short-term PM2.5 exposures may lead to adverse health effects. Standard integrated filter-based techniques used in PM2.5 compliance monitoring networks and in most past PM2.5 epidemiologic studies collect samples over 24-hr periods and thus are unable to capture these transient events. Moreover, health-effects studies that focus on daily PM2.5 mass alone cannot evaluate the health implications of the unique and variable chemical properties of these episodes.

Alteration of gap junctions and connexins in the right atrial appendage during cardiopulmonary bypass

OBJECTIVES

We investigated the influence of cardiopulmonary bypass on cardiomyocyte gap junctions and connexins.

METHODS

Samples were collected at intervals during operation from the right atrial appendage in 21 patients (mean [+/- SD] age 55 +/- 21 years). Immunodetection of connexins was conducted by Western blotting and confocal microscopy with parallel electron microscopic examination of gap junctions.

RESULTS

Downregulation of connexin 43 during the course of operation occurred in more than half of the patients. The mean densitometric value of connexin 43 decreased by 23%, with samples from patients with coronary artery disease showing a greater reduction than seen in those from patients with other diseases (31% +/- 22% vs 10% +/- 24%, P =.04). Such alterations were confirmed by confocal microscopy, which also demonstrated reduced connexin 45 immunolabeling in most patients. Electron microscopy revealed a reduction in the dimensions of cell membrane-located gap junctions and more frequent intracytoplasmic gap junctional membrane in samples from later time points (P =.04).

CONCLUSIONS

Downregulation of connexins accompanied by a reduction in gap junctions is common in the cardiomyocytes of the right atrial appendage during cardiopulmonary bypass. The association of a marked reduction in connexin 43 with coronary artery disease may imply inadequate intraoperative cardiac protection in patients with this disease.

2',5'-Dihydroxychalcone down-regulates endothelial connexin43 gap junctions and affects MAP kinase activation

We examined the effect of 2',5'-dihydroxychalcone on connexin43 (Cx43) expression and gap-junctional communication in human umbilical vein endothelial cells (HUVEC). The result showed that expression of Cx43 is rapidly reduced by 2',5'-dihydroxychalcone in a dose-dependent manner, Concomitantly, the communication function, determined by fluorescence recovery after photobleaching (FRAP), is decreased. We further investigated whether the mitogen-activated protein (MAP) kinase and the degradation pathway of gap junctions are involved in these processes. Although the change of Cx43 is not affected by the level of fetal calf serum (FCS) used in the medium, activation of MAP kinase varies, depending on the FCS level. At a low level (0.5%), the chalcone inhibits the activation, like PD98059, a specific inhibitor of MAP kinase kinase. However, at a high level (20%), MAP kinase is activated. On the other hand, the chalcone's down-regulating effect on Cx43, while is totally blocked by protease inhibitors leupeptin and N-acetyl-leucyl-norleucinal (ALLN), persists in the presence of PD98059, We concluded that 2',5'-dihydroxychalcone down-regulates Cx43 expression and gap-junctional communication in the HUVEC via enhancement of the proteolysis pathway, and this compound possesses dual effects on MAP kinase activation.

Activation of the beta-catenin/Lef-Tcf pathway is obligate for formation of primitive endoderm by mouse F9 totipotent teratocarcinoma cells in response to retinoic acid

The morphogen retinoic acid promotes the formation of primitive endoderm in mouse F9 teratocarcinoma cells as does the stimulation of the Frizzled-1 pathway. We investigated whether the beta-catenin/Lef-Tcf-sensitive transcriptional pathway activated by Frizzled-1 plays a role in the retinoic acid-induced pathway to primitive endoderm formation. An analysis of Lef-Tcf-sensitive transcription reveals increased transcription at 1 and 4 h post-treatment with retinoic acid. The stimulation of Lef-Tcf-sensitive transcription as well as the formation of primitive endoderm was accompanied by the stabilization of beta-catenin as observed in activation of the Frizzled-1 pathway. Transient transfection of F9 cells with an expression vector harboring a dominant-negative mutant of Tcf4 resulted in the attenuation of both the increase in Lef-Tcf-sensitive transcription and formation of primitive endoderm in response to the morphogen. Clones stably transfected to express the dominant-negative Tcf4 displayed a block in retinoic acid-induced activation of Lef-Tcf-sensitive transcription and primitive endoderm formation. These data reveal the obligate role of the beta-catenin/Lef-Tcf transcriptional pathway in the action of the morphogen retinoic acid.

Heterogeneity of myocardial sleeve morphology and gap junctions in canine superior vena cava

BACKGROUND

The myocardial sleeve of the superior vena cava (SVC) has been identified as a potential initiating focus in atrial fibrillation, but information on cell-to-cell linkage at this site is lacking.

METHODS AND RESULTS

We examined the SVC in 8 dogs by immunoconfocal and electron microscopy. Cardiomyocytes outlined with vinculin and bearing striations positive for alpha-actinin are found in the proximal segment of the SVC. These cells, grouped in bundles of various orientations according to location, extend cephalically as far as 3 cm from the right atrium (RA)-SVC junction. Comparison between the junctional level and the level 2 cm distal shows that the myocardial layer in the latter is thinner and not as compact and is composed of longer cells (87.3+/-15.7 versus 71.6+/-14.4 micrometer, P<0.01). Gap junctions made of connexin43 (Cx43), Cx40, and Cx45 are aggregated mainly at the intercalated disks, and colocalization of connexins is a common feature throughout the myocardial sleeve. Areas of atypical expression exist, however, characterized by a center of abundant Cx43 labels surrounded by a periphery of scattered tiny Cx40-labeled spots. Although in the ventral subluminal compact myocardial layer, individual cells at both levels are surrounded by similar numbers of cells, the number of aggregation of labeled gap junctions at the distal level is less (2.3+/-0.6 versus 3.7+/-0.9, P<0.01). In addition, electron-microscopic examination demonstrates that the gap junctions at the distal level are smaller in size (0.37+/-0.30 versus 0.55+/-0.34 micrometer, P<0.01).

CONCLUSIONS

The myocardial sleeve in the canine SVC is a heterogeneous structure, which could potentially form a substrate for heterogeneity of electrical coupling.

Identification of a role for the sialomucin CD164 in myogenic differentiation by signal sequence trapping in yeast

Determination and differentiation of skeletal muscle precursors requires cell-cell contact, but the full range of cell surface proteins that mediate this requirement and the mechanisms by which they work are not known. To identify participants in cell contact-mediated regulation of myogenesis, genes that encode secreted proteins specifically upregulated during differentiation of C2C12 myoblasts were identified by the yeast signal sequence trap method (K. A. Jacobs, L. A. Collins-Racie, M. Colbert, M. Duckett, M. Golden-Fleet, K. Kelleher, R. Kriz, E. R. La Vallie, D. Merberg, V. Spaulding, J. Stover, M. J. Williamson, and J. M. McCoy, Gene 198:289-296, 1997), followed by RNA expression analysis. We report here the identification of CD164 as a gene expressed in proliferating C2C12 cells that is upregulated during differentiation. CD164 encodes a widely expressed cell surface sialomucin that has been implicated in regulation of cell proliferation and adhesion during hematopoiesis. Stable overexpression of CD164 in C2C12 and F3 myoblasts enhanced their differentiation, as assessed by both morphological and biochemical criteria. Furthermore, expression of antisense CD164 or soluble extracellular regions of CD164 inhibited myogenic differentiation. Treatment of C2C12 cells with sialidase or O-sialoglycoprotease, two enzymes previously reported to destroy functional epitopes on CD164, also inhibited differentiation. These data indicate that (i) CD164 may play a rate-limiting role in differentiation of cultured myoblasts, (ii) sialomucins represent a class of potential effectors of cell contact-mediated regulation of myogenesis, and (iii) carbohydrate-based cell recognition may play a role in mediating this phenomenon.

Structure-activity relationship studies of isoquinolinone type anticancer agent

Substituted isoquinolin-1-ones (1) were synthesized to test their in vitro anticancer activity. 3-Biphenyl-N-methylisoquinolin-1-one (7) showed the most potent anticancer activity against five different human cancer cell lines.

Mode of antiviral activity of water soluble components isolated from Elfvingia applanata on vesicular stomatitis virus

A preparation of water soluble components (EA) was made from carpophores of Elfvingia applanata (Pers.) Karst and its in vitro antiviral activity on vesicular stomatitis virus [(Indiana serotype, VSV(IND)] was investigated by plaque reduction assay. EA exhibited potent antiviral activity on VSV(IND) growth and negligible cytotoxicity on Vero cells, 50% effective concentration (EC50) of 104 microg/ml and 50% cytotoxic concentration (CC50) of 3,793 microg/ml, respectively. Selectivity index (SI, CC50/EC50) of EA on Vero cell and VSV(IND) was about 36.5. EA did not display either a direct virucidal effect on VSV(IND) or induction of antiviral substance by Vero cells upon its treatment. Thus, the mode of antiviral activity of EA was studied at steps of viral adsorption onto cell. When both EA and virus were added to cell monolayers, titer of cell-free virus in culture supernatant increased in ca. 30-40% compared with that of control group and titer of cell-associated virus was 60-100% higher than that of control group. These results suggested that antiviral activity of EA on VSV(IND) might be due to the hindrance of viral entry to cells at either endocytosis or loss of envelope.

Virtual reality for relearning daily living skills

The explosive increase in the power of computers has enabled the creation of fast, interactive 3D environments, sometimes called virtual reality (VR). This technology, often associated with arcade games, is increasingly being used for more serious applications. This paper describes research showing transfer of skills from a virtual environment to the real world. We then describe our VR authoring tool and an application to help cognitively impaired individuals relearn important daily living skills. Additionally we describe the development of a prototype networked system to enable a doctor to monitor remotely the rehabilitation of a group of patients.

Biochemical characterization of extracellular cAMP-dependent protein kinase as a tumor marker

In a recent report (Cho et al., Proc. Natl. Acad. Sci. USA 97, 835-840, 2000), we showed that cancer cells of various cell types secrete cAMP-dependent protein kinase (PKA) into the conditioned medium and that in the serum of cancer patients this extracellular PKA (ECPKA) is upregulated 10-fold as compared with normal serum. Here, we characterized the enzymatic properties of ECPKA that is present in the conditioned medium of PC3M prostate cancer cells and in the serum of cancer patients, and we compared ECPKA with PKA found in the cell extracts of PC3M cells. ECPKA present in the conditioned medium and human serum was not activated by cAMP addition, but intracellular PKA activity was totally dependent on the addition of cAMP. This indicates that the ECPKA is present in active, free C subunit form, whereas intracellular PKA is present in inactive holoenzyme form. ECPKA activity increased in a substrate concentration- and time-dependent manner, as did intracellular PKA. Both ECPKA and intracellular PKA activities were specifically inhibited by the PKA inhibitor protein, PKI. However, ECPKA activity was more temperature-sensitive than intracellular PKA; after two cycles of freezing/thawing, only 20% of initial ECPKA activity was detected compared with over 40% of intracellular PKA activity. Western blot analysis revealed the presence of a 40 kDa C(alpha) subunit of PKA in both conditioned medium and in the serum of cancer patients. These results suggest that ECPKA, out of the context of cAMP regulation, may function as a growth factor promoting cell growth and transformation; thus, it may serve as a tumor biomarker.

Age-related alteration of gap junction distribution and connexin expression in rat aortic endothelium

We investigated endothelial gap junctions and their three component connexins, connexin37 (Cx37), Cx40, and Cx43, during growth and senescence in rat aorta by en face immunoconfocal microscopy and electron microscopy. Gap junction spots labeled by specific antisera against Cx37, Cx40, and Cx43 were quantified at 1 day, 7 days, 28 days, 16 months, and > or =20 months of age, and the relationship between the connexins was examined by co-localization analysis. At birth, all three connexins were abundantly expressed; the number and total area of connexin spots then declined within 1 week (p<0.05 for each connexin). From 1 week, each connexin showed a distinct temporal expression pattern. Whereas Cx43 signal decreased progressively, Cx37 signal fluctuated in a downward trend. By contrast, Cx40 maintained an abundant level until > or =20 months of age (> or =20 months vs. 28 days, p<0.05 for number and total connexin signal area). These patterns were associated with changes in endothelial cell morphology. Double-label analysis showed that the extent of co-localization of connexins to the same gap junctional spot was age-dependent [>70% at birth and 28 days old; <70% at later stages (p<0.05)]. We conclude that expression of the three connexins in aortic endothelium is age-related, implying specific intercellular communication requirements during different stages after birth.

Compensatory stabilization of RIIbeta protein, cell cycle deregulation, and growth arrest in colon and prostate carcinoma cells by antisense-directed down-regulation of protein kinase A RIalpha protein

The cyclic AMP-dependent protein kinase (PKA) exists in two isoforms, PKA-I (type I) and PKA-II (type II), that contain an identical catalytic (C) subunit but distinct regulatory (R) subunits, RI and RII, respectively. Increased expression of RIalpha/PKA-I has been shown in human cancer cell lines, in primary tumors, in cells after transformation, and in cells upon stimulation of growth. We have shown previously that a single-injection RI, antisense treatment results in a reduction in RIalpha and PKA-I expression and sustained inhibition of human colon carcinoma growth in athymic mice (M. Nesterova and Y. S. Cho-Chung, Nat. Med., 1: 528-533, 1995). Growth inhibition accompanied reduction in RIalpha/PKA-I expression and compensatory increases in RIIbeta protein and PKA-IIbeta, the RIIbeta-containing holoenzyme. Here, we report that these in vivo findings are consistent with observations made in cancer cells in culture. We demonstrate that the antisense depletion of RIalpha in cancer cells results in increased RIIbeta protein without increasing the rate of RIIbeta synthesis or RIIbeta mRNA levels. Pulse-chase experiments revealed a 3-6-fold increase in the half-life of RIIbeta protein in antisense-treated colon and prostate carcinoma cells with little or no change in the half-lives of RIalpha, RIIalpha, and Calpha proteins. Compensation by RIIbeta stabilization may represent a novel biochemical adaptation mechanism of the cell in response to sequence-specific loss of RIalpha expression, which leads to sustained down-regulation of PKA-I activity and inhibition of tumor growth.

CRE-decoy oligonucleotide-inhibition of gene expression and tumor growth

Nucleic acid molecules with high affinities for a target transcription factor can be introduced into cells as decoy cis-elements to bind these factors and alter gene expression. This review discusses a synthetic single-stranded palindromic oligonucleotide, which self-hybridizes to form a duplex/hairpin and competes with cAMP response element (CRE) enhancers for binding transcription factors. This oligonucleotide inhibits CRE- and Ap-1-directed gene transcription and promotes growth inhibition in vitro and in vivo in a broad spectrum of cancer cells, without adversely affecting normal cell growth. Evidence presented here suggests that the CRE-decoy oligonucleotide can provide a powerful new means of combating cancers, viral diseases, and other pathological conditions by regulating the expression of cAMP-responsive genes.

CRE-transcription factor decoy oligonucleotide inhibition of MCF-7 breast cancer cells: cross-talk with p53 signaling pathway

The CRE, 5'-TGACGTCA-3', has been described as the consensus sequence for the cis-element that directs cAMP-regulated gene expression. Many transcription factors bind to this element and regulate the expression of a wide variety of cellular and viral genes. We have shown that CRE-transcription factor decoy oligonucleotide restrains the growth of cancer cells in vitro and in vivo [Park, Y. G., Nesterova, M., Agrawal, S., and Cho-Chung, Y. S. (1999) J. Biol. Chem. 274, 1573-1580]. The growth inhibition was accompanied by changes in cell morphology and apoptosis. To elucidate the molecular mechanism(s) of the growth inhibition by the CRE-decoy oligonucleotide, we investigated the p53 signaling pathway. Herein, we report that CRE-decoy oligonucleotide treatment results in an increase in the p53 protein level in MCF-7 human breast cancer cells that express wild-type p53. The p21WAF1/Cip1 protein levels were also increased in the CRE-decoy oligonucleotide treated cells accompanying a reduction in Cdk2- and cyclin E-dependent kinase activity and pRb phosphorylation. Pulse-chase experiments reveal that the p53 upregulation was due to increased stability of the protein. The decoy oligonucleotide treatment also enhanced the p53 promotor-directed transcription in vivo along with the increase in p53-CBP (CREB-binding protein) complex formation. Thus, the stabilization and activation of p53 may have contributed to the growth inhibition induced by CRE-transcription factor decoy oligonucleotide in MCF-7 breast cancer cells. This decoy oligonucleotide approach offers great promise as a tool for defining cellular regulatory processes and treating cancer and other diseases.

Production of two different catalase-peroxidases by Deinococcus radiophilus

The production of two kinds of catalase-peroxidase, viz. catalase-2 and catalase-3 of Deinococcus radiophilus varied depending upon growth phases and oxidative stress. A gradual increase in total catalase activity occurred during exponential and stationary phase. Electrophoretic resolution of these catalases in Deinococcal cell extracts revealed the uniform occurrence of catalase-2 and the appearance of catalase-3 only during the late exponential and stationary phase. A substantial increase in total catalase was observed in either hydrogen peroxide- or UV-treated cells. Monitoring of D. radiophilus catalase activity in the oxidative stressed and non-treated cells by gel electrophoresis followed by densitometry revealed the several-fold increase in catalase-3, which is above the constant level of catalase-2. The occurrence of catalase-3 and catalase-2 revealed by fractionation of sucrose-shocked cells suggests that catalase-3 is a cytosolic inducible enzyme whereas catalase-2 is the membrane-associated constitutive enzyme.

Extracellular protein kinase A as a cancer biomarker: its expression by tumor cells and reversal by a myristate-lacking Calpha and RIIbeta subunit overexpression

Overexpression of cAMP-dependent protein kinase (PKA) type I isozyme is associated with cell proliferation and neoplastic transformation. The presence of PKA on the external surface of LS-174T human colon carcinoma cells has been shown. Here, we show that cancer cells of various cell types excrete PKA into the conditioned medium. This extracellular PKA (ECPKA) is present in active, free catalytic subunit (C subunit) form, and its activity is specifically inhibited by PKA inhibitory protein, PKI. Overexpression of the Calpha or RIalpha subunit gene of PKA in an expression vector, which up-regulates intracellular PKA type I, markedly up-regulates ECPKA expression. In contrast, overexpression of the RIIbeta subunit, which eliminates PKA type I, up-regulates PKA type II, and reverts the transformed phenotype, down-regulates ECPKA. A mutation in the Calpha gene that prevents myristylation allows the intracellular PKA up-regulation but blocks the ECPKA increase, suggesting that the NH(2)-terminal myristyl group of Calpha is required for the ECPKA expression. In serum of cancer patients, the ECPKA expression is up-regulated 10-fold as compared with normal serum. These results indicate that the ECPKA expression is an ordered cellular response of a living cell to actively exclude excess intracellular PKA molecules from the cell. This phenomenon is up-regulated in tumor cells and has an inverse relationship with the hormone dependency of breast cancer. Thus, the extracellular PKA may serve as a potential diagnostic and prognostic marker for cancer.

Antisense DNA-targeting protein kinase A-RIA subunit: a novel approach to cancer treatment

Enhanced expression of the RIa subunit of cAMP-dependent protein kinase type I (PKA-I) has been shown during carcinogenesis, in human cancer cell lines and in primary tumors. We demonstrate that the sequence-specific inhibition of RIa gene expression by antisense oligonucleotides results in the differentiation of leukemia cells and growth arrest of cancer cells of epithelial origin and tumors in mice. The loss of RI by the antisense results in rapid increase in the half-life of the competitor molecule, RII protein, via its stabilization in a holoenzyme complex (PKA-II) that insures depletion of PKA-I and sustained inhibition of tumor growth. RI antisense, which restrains tumor cell growth by turning on the signals for blockade of tumor cell survival, namely blockade of the tyrosine kinase signaling, cell cycle deregulation and apoptosis, provides a single gene-targeting approach to treatment of cancer.

Suppression of microphthalmia transcriptional activity by its association with protein kinase C-interacting protein 1 in mast cells

Microphthalmia (mi) is a transcription factor that plays a major role in the regulation of growth and function in mast cells and melanocytes. Association of mi with other proteins is a critical step in the regulation of mi-mediated transcriptional activation. We found protein kinase C-interacting protein 1 (PKCI) specifically associated with mi in yeast two-hybrid screening. Immunoprecipitation of mi from quiescent rat basophilic leukemic cells or mouse melanocytes resulted in the specific co-immunoprecipitation of PKCI. This association was significantly reduced on engagement of the surface FcepsilonRI of mast cells or engagement of the Kit receptor on melanocytes. Hence, cell activation caused disengagement of mi from PKCI. Microphthalmia was previously shown to activate the mouse mast cell protease 6 (mMCP-6) promoter. Cotransfection of mi with PKCI in NIH 3T3 fibroblasts containing an mMCP-6 promoter-luciferase reporter demonstrated an up to 94% inhibition of mi-mediated transcriptional activation. PKCI by itself, although localized in the cytosol and nucleus of the cells, has no known physiological function and did not demonstrate transcriptional activity. Its ability to suppres mi transcriptional activity in the transient transfected fibroblast system suggests that it can function in vivo as a negative regulator of mi-induced transcriptional activation.

Oligonucleotides as transcription factor decoys

Cellular and molecular research has been focused to develop a means to regulate gene expression in an effort to treat and cure a variety of diseases and abnormal physiological conditions. A successful oligonucleotide-based approach has been the use of synthetic oligonucleotides containing an enhancer element that can penetrate cells, bind sequence-specific DNA-binding proteins and interfere with transcription in vivo. This review describes such decoy oligonucleotides that exhibit high affinity for a target transcription factor and successfully interfere with transcription in vivo. Evidence presented here shows that the decoy oligonucleotide technology offers great promise as a tool for defining cellular regulatory processes and for treating cancer, viral diseases and other pathological conditions.

Involvement of glucocorticoid receptor in the induction of differentiation by ginsenosides in F9 teratocarcinoma cells

We have previously reported that ginsenosides Rh1 and Rh2 induced the differentiation of F9 teratocarcinoma stem cells [Lee, Y. N., Lee, H. Y., Chung, H. Y., Kim, S. I., Lee, S. K., Park, B. C. and Kim, K. W., In vitro induction of differentiation by ginsenosides in F9 teratocarcinoma cells. Eur. J. Cancer 1996, 32, 1420-1428.]. Since the chemical structure of Rh1 and Rh2 is very similar to that of dexamethasone, a synthetic glucocorticoid, we investigated whether Rh1 and Rh2 act through the glucocorticoid receptor (GR). Immunocytochemistry showed that Rh1 or Rh2 increased the nuclear translocation of GR in the same manner of dexamethasone. In the gel shift assay, glucocorticoid response element (GRE) binding protein in F9 cells was increased by Rh1 or Rh2. To confirm whether the increased binding protein is GR, we performed the competition assay with unlabeled GRE as a specific competitor. Moreover, supershift assay with the GR antibody showed that the binding proteins are GR. In addition, to confirm the Rh1 or Rh2-induced transactivation of GRE promoter, we cotransfected GR expression vector and GRE-luciferase vector. In the luciferase assay, Rh1 or Rh2 potently induced luciferase activity and this induction was blocked by RU486, a potent GR antagonist. Taken together, we suggest that ginsenosides Rh1 and Rh2 may induce the differentiation of F9 cells by stimulating the nuclear translocation of GR.

The RIIbeta regulatory subunit of protein kinase A binds to cAMP response element: an alternative cAMP signaling pathway

cAMP, through the activation of cAMP-dependent protein kinase (PKA), is involved in transcriptional regulation. In eukaryotic cells, cAMP is not considered to alter the binding affinity of CREB/ATF to cAMP-responsive element (CRE) but to induce serine phosphorylation and consequent increase in transcriptional activity. In contrast, in prokaryotic cells, cAMP enhances the DNA binding of the catabolite repressor protein to regulate the transcription of several operons. The structural similarity of the cAMP binding sites in catabolite repressor protein and regulatory subunit of PKA type II (RII) suggested the possibility of a similar role for RII in eukaryotic gene regulation. Herein we report that RIIbeta subunit of PKA is a transcription factor capable of interacting physically and functionally with a CRE. In contrast to CREB/ATF, the binding of RIIbeta to a CRE was enhanced by cAMP, and in addition, RIIbeta exhibited transcriptional activity as a Gal4-RIIbeta fusion protein. These experiments identify RIIbeta as a component of an alternative pathway for regulation of CRE-directed transcription in eukaryotic cells.

Cloning and characterization of two catA genes in Acinetobacter lwoffii K24

Two novel type I catechol 1,2-dioxygenases inducible on aniline media were isolated from Acinetobacter lwoffii K24. Although the two purified enzymes, CD I1 and CD I2, had similar intradiol cleavage activities, they showed different substrate specificities for catechol analogs, physicochemical properties, and amino acid sequences. Two catA genes, catA1 and catA2, encoding by CD I1 and CD I2, respectively, were isolated from the A. lwoffii K24 genomic library by using colony hybridization and PCR. Two DNA fragments containing the catA1 and catA2 genes were located on separate regions of the chromosome. They contained open reading frames encoding 33.4- and 30.4-kDa proteins. The amino acid sequences of the two proteins matched well with previously determined sequences. Interestingly, further analysis of the two DNA fragments revealed the locations of the catB and catC genes as well. Moreover, the DNA fragment containing catA1 had a cluster of genes in the order catB1-catC1-catA1 while the catB2-catA2-catC2 arrangement was found in the catA2 DNA fragment. These results may provide an explanation of the different substrate specificities and physicochemical properties of CD I1 and CD I2.

In vitro induction of differentiation by ginsenoides in F9 teratocarcinoma cells

The aim of this study was to determine the ability of the ginsenosides, extracts of Panax ginseng C.A. Meyer, to cause differentiation of F9 teratocarcinoma stem cells as a model system. F9 stem cells cultured in the presence of the ginsenosides together with dibutyryl cyclic AMP (dbcAMP) became parietal endoderm-like cells. Moreover, the expression of differentiation marker genes, such as laminin B1 and type IV collagen, was increased after treatment with the ginsenosides. Among the various purified ginsenosides, Rh1 and Rh2 were the most effective at causing differentiation of F9 cells. Since ginsenosides and glucocorticoid hormone have similar chemical structures, we examined the possibility of the involvement of a glucocorticoid receptor (GR) in the differentiation process induced by the ginsenosides. According to Southwestern blot analysis, a 94 kDa protein regarded as a GR was detected in F9 cells cultured in the medium containing the ginsenosides Rh1 or Rh2. In addition, F9 stem cells treated with the ginsenosides Rh1 or Rh2 and with RU486, a glucocorticoid antagonist with a high affinity for the GR, did not differentiate into endoderm cells morphologically, and the expression of laminin B1 gene was not induced in these cells. In a gel mobility shift assay, protein factors capable of binding to the glucocorticoid responsive element (GRE) specifically were detected in nuclear extracts of the ginsenoside-treated F9 cells. Moreover, overexpression of GR by cotransfection of GR expression vector and GRE-luciferase vector enhanced the transactivation activity of GRE promoter in the presence of ginsenosides Rh1 or Rh2 and was further augmented by dbcAMP. In addition, ginsenosides Rh1 and Rh2 bound to a GR assessed by whole-cell binding assay, even though the specific binding affinity was weaker compared to dexamethasone. Based on these data, we suggest that the ginsenosides Rh1 and Rh2 cause the differentiation of F9 cells and the effects of ginsenosides might be exerted via binding with a GR or its analogous nuclear receptor.

Taurine intake of Korean breast-fed infants during lactation

i. Taurine concentrations of human milk of nonvegetarians and lacto-ovovegetarians decreased significantly during the course of lactation. Taurine concentrations in lacto-ovovegetarians after 90 days postpartum were lower than those of nonvegetarians. Taurine concentrations of human milk by 150 days postpartum were: nonvegetarian 248-434 nmol/ml (31.0-54.4 mg/L); lacto-ovovegetarian 153-418 nmol/ml (19.1-52.3 mg/L). ii. Taurine intakes in infants of lacto-ovovegetarians decreased significantly during lactation, unlike from the pattern in infants of nonvegetarians. Taurine intakes in infants of lacto-ovovegetarians at 90, 120 and 150 days postpartum were lower, compared with those in nonvegetarians. Taurine intakes in infants by 150 days postpartum were: Infants of nonvegetarians 169-229 mumol/day (21.1-28.6 mg/day); Infants of lacto-ovovegetarians 106-210 mumol/day (21.1-28.6 mg/day). iii. This study showed that the taurine concentration in human milk and the taurine intake of infants were different during lactation between nonvegetarians and lacto-ovovegetarians, and that the intake per kg body weight decreased during lactation. Results suggest that the differences observed might be due to the effect of consumption of different types of food.

Prevalence of hepatitis C antibody in patients with chronic liver disease and hepatocellular carcinoma in Korea

To investigate the contribution of hepatitis C virus (HCV) to chronic liver disease and hepatocellular carcinoma (HCC) in Korea, antibodies to HCV (anti-HCV) were tested by enzyme immunoassay in 1759 patients with chronic liver disease and HCC, and in 808 healthy adults. The prevalence of anti-HCV was 1.6% in 808 controls. Anti-HCV was present in 32 (7.7%) of 418 hepatitis B surface antigen (HBsAg)-positive and 128 (53.1%) of 241 HBsAg-negative patients with chronic hepatitis, 16 (6.0%) of 265 HBsAg-positive and 90 (30.5%) of 295 HBsAg-negative patients with liver cirrhosis, and 16 (4.8%) of 330 HBsAg-positive and 61 (29.0%) of 210 HBsAg-negative patients with HCC. Antibodies to hepatitis B core antigen (anti-HBc) were present in 80-88% of patients who were seropositive for anti-HCV and seronegative for HBsAg. Among the sera from 114 patients with HBsAg-negative and anti-HCV-positive chronic liver diseases, HBV DNA and HCV RNA were detected by polymerase chain reaction (PCR) in 54 (47.4%) and 61 (53.3%), respectively. Both HBV DNA and HCV RNA were detected in 4 (4.4%) samples. The mean age of the patients with both HBsAg and anti-HCV was not different from that of patients who were seropositive for HBsAg alone. These findings indicate that current and/or past HBV infection is still the main cause of chronic liver disease in Korea.(ABSTRACT TRUNCATED AT 250 WORDS)

Leiomyosarcoma of the broad ligament--report of two cases

Leiomyosarcoma of the broad ligament (LBL) is a very rare tumor. Up to 1989, there had been only 7 cases reported in the English literature. During recent 12 years, we have had 15 cases of leiomyosarcoma in our department. Among them, there were two cases of LBL. The others were leiomyosarcoma of the uterine corpus. The first patient was 36 years old. She received total abdominal hysterectomy, bilateral salpingo-oophorectomy and paraaortic lymph node sampling followed by chemotherapy with adriamycin. Intra-abdominal recurrence with hepatic metastasis occurred 18 months after operation and she received palliative radiotherapy. The second patient was 65 years old and received subtotal hysterectomy, bilateral salpingo-oophorectomy, omental biopsy and suprapubic cystostomy followed also by chemotherapy with adriamycin. She received segmental resection of ileum and ileostomy due to intestinal obstruction caused by metastasis 5 months after her initial operation. Both patients were still alive when reported with 33 and 26 months of survival, respectively. The nature and management for LBL are scarcely reported, accumulation of cases and clinical experiences are needed.

Amniotic fluid index measurement with the four-quadrant technique during pregnancy

Eleven hundred thirty-four pregnant women with reliable dates underwent ultrasound evaluation for amniotic fluid index (AFI) measurement with the modified four-quadrant technique. We found that from 13 weeks' gestation the AFI rose progressively until 26 weeks. From then to 38 weeks the AFI measurements demonstrated little variation. After 38 weeks the AFI appeared to decline gradually. In the third trimester the mean AFI was 16.0 +/- 4.8 cm; 5% of cases had an AFI less than or equal to 8 cm, and 5% had an AFI greater than or equal to 24 cm. These results confirm the reproducibility of the semiquantitative technique and suggest that in estimating amniotic fluid volume, AFI measurement may be a more appropriate means than measurement of the single largest pocket or subjective assessment. Serial AFI measurement would be an effective way of assessing fetal status throughout pregnancy.

Malignant mixed müllerian tumor of fallopian tube. Report of a case and review of literature

This is a case of malignant mixed Müllerian tumor arising primarily from the fallopian tube. The tumor was distant metastasis to the omentum and the serosa of the sigmoid colon. Literatures published in the last two decades are reviewed and discussed.

Meigs' syndrome--a case report

Bilateral ovarian fibromas combined with as and hydrothorax is a rare disorder. A case of bilateral ovarian fibromas combined with ascites and hyrothorax is presented. The ascites and hydrothorax disappeared spontaneously after removal of the ovarian tumors.

Effects of monomeric and polymeric diets on small intestine following massive resection

Since the introduction of long-term total parental nutrition, it has been possible to raise the survival rate in patients with massive intestinal resection. How to increase the remaining intestinal mucosa hyperplasia in these patients has become the focus of many studies. Early postoperative enteral feeding with exogenous intraluminal nutrition was considered to be one of the most essential factors. The best enteral food pattern, however, is still not conclusive. In this study, we used the animal model of rats with 60% small intestinal resection, giving them different kinds of enteral diets through gastrostomy tubes. The monomeric diet included amino acid, glucose, disaccharide, and triglyceride. The polymeric diet included the usual source of nutrition such as protein, polysaccharide, and fat. The rats were killed three weeks later. Histopathological changes of the remaining bowel and H3 thymidine incorporation to mucosal DNa were measured. We found: (1) hyperplasia of the remaining bowel in the 60% resected rats was definitely increased more than the rats of the sham operation; (2) from the protein content, the DNA content of mucosa cells, the villus height and crypt depth points of view, the polymeric diet fed rats had a better adaptation; (3) on the 21st postoperative day, the DNA synthetic rate was still very high in polymeric diet fed rats, but returned to preoperative levels in rats fed with a monomeric diet. Our conclusion of this study is that a polymeric diet can contribute to a better intestinal mucosa regeneration than a monomeric diet in the rats with massive intestinal resection.