Modification of surface glycan by expression of beta-1,4-N-acetyl-galactosaminyltransferase (B4GALNT2) confers resistance to multiple viruses infection in chicken fibroblast cell

Introduction

Infectious viruses in poultry, such as avian influenza virus (AIV) and Newcastle disease virus (NDV), are one of the most major threats to the poultry industry, resulting in enormous economic losses. AIVs and NDVs preferentially recognize α-2,3-linked sialic acid to bind to target cells. The human beta-1,4-N-acetyl-galactosaminyltransferase 2 (B4GALNT2) modifies α-2,3-linked sialic acid-containing glycan by transferring N-acetylgalactosamine to the sub-terminal galactose of the glycan, thus playing a pivotal role in preventing viruses from binding to cell surfaces. However, chickens lack a homolog of the B4GALNT2 gene.

Methods

Here, we precisely tagged the human B4GALNT2 gene downstream of the chicken GAPDH so that the engineered cells constitutively express the human B4GALNT2. We performed a lectin binding assay to analyze the modification of α-2,3-linked sialic acid-containing glycan by human B4GALNT2. Additionally, we infected the cells with AIV and NDV and compared cell survivability, viral gene transcription, and viral titer using the WST-1 assay, RT-qPCR and TCID50 assay, respectively.

Results

We validated human B4GALNT2 successfully modified α-2,3-linked sialic acid-containing glycan in chicken DF-1 cells. Following viral infection, we showed that human B4GALNT2 reduced infection of two AIV subtypes and NDV at 12-, 24-, and 36-hours post-infection. Moreover, cells expressing human B4GALNT2 showed significantly higher cell survivability compared to wild-type DF-1 cells, and viral gene expression was significantly reduced in the cells expressing human B4GALNT2.

Discussion

Collectively, these results suggest that artificially expressing human B4GALNT2 in chicken is a promising strategy to acquire broad resistance against infectious viruses with a preference for α-2,3-linked sialic acids such as AIV and NDV.

Plant-based, adjuvant-free, potent multivalent vaccines for avian influenza virus via Lactococcus surface display

Influenza epidemics frequently and unpredictably break out all over the world, and seriously affect the breeding industry and human activity. Inactivated and live attenuated viruses have been used as protective vaccines but exhibit high risks for biosafety. Subunit vaccines enjoy high biosafety and specificity but have a few weak points compared to inactivated virus or live attenuated virus vaccines, especially in low immunogenicity. In this study, we developed a new subunit vaccine platform for a potent, adjuvant-free, and multivalent vaccination. The ectodomains of hemagglutinins (HAs) of influenza viruses were expressed in plants as trimers (tHAs) to mimic their native forms. tHAs in plant extracts were directly used without purification for binding to inactivated Lactococcus (iLact) to produce iLact-tHAs, an antigen-carrying bacteria-like particle (BLP). tHAs BLP showed strong immune responses in mice and chickens without adjuvants. Moreover, simultaneous injection of two different antigens by two different formulas, tHAH5N6 + H9N2 BLP or a combination of tHAH5N6 BLP and tHAH9N2 BLP, led to strong immune responses to both antigens. Based on these results, we propose combinations of plant-based antigen production and BLP-based delivery as a highly potent and cost-effective platform for multivalent vaccination for subunit vaccines.

Highly Selective Multiplex Quantitative Polymerase Chain Reaction with a Nanomaterial Composite Hydrogel for Precise Diagnosis of Viral Infection

As viruses have been threatening global public health, fast diagnosis has been critical to effective disease management and control. Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) is now widely used as the gold standard for detecting viruses. Although a multiplex assay is essential for identifying virus types and subtypes, the poor multiplicity of RT-qPCR makes it laborious and time-consuming. In this paper, we describe the development of a multiplex RT-qPCR platform with hydrogel microparticles acting as independent reactors in a single reaction. To build target-specific particles, target-specific primers and probes are integrated into the particles in the form of noncovalent composites with boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs). The thermal release characteristics of DNA, primer, and probe from the composites of primer-BNNT and probe-CNT allow primer and probe to be stored in particles during particle production and to be delivered into the reaction. In addition, BNNT did not absorb but preserved the fluorescent signal, while CNT protected the fluorophore of the probe from the free radicals present during particle production. Bicompartmental primer-incorporated network (bcPIN) particles were designed to harness the distinctive properties of two nanomaterials. The bcPIN particles showed a high RT-qPCR efficiency of over 90% and effective suppression of non-specific reactions. 16-plex RT-qPCR has been achieved simply by recruiting differently coded bcPIN particles for each target. As a proof of concept, multiplex one-step RT-qPCR was successfully demonstrated with a simple reaction protocol.

Fully Packaged Portable Thin Film Biosensor for the Direct Detection of Highly Pathogenic Viruses from On-Site Samples

The thin film transistor (TFT) is a promising biosensor system with great sensitivity, label-free detection, and a quick response time. However, even though the TFT sensor has such advantageous characteristics, the disadvantages hamper the TFT sensor's application in the clinical field. The TFT is susceptible to light, noise, vibration, and limited usage, and this significantly limits its on-site potential as a practical biosensor. Herein, we developed a fully packaged, portable TFT electrochemical biosensor into a chip form, providing both portability through minimizing the laboratory equipment size and multiple safe usages by protecting the semiconductor sensor. Additionally, a safe environment that serves as a miniature probe station minimizes the previously mentioned disadvantages, while providing the means to properly link the TFT biosensor with a portable analyzer. The biosensor was taken into a biosafety level 3 (BSL-3) laboratory setting to analyze highly pathogenic avian influenza virus (HPAIV) samples. This virus quickly accumulates within a host, and therefore, early stage detection is critical to deterring the further spread of the deadly disease to other areas. However, current on-site methods have poor limits of detection (10⁵-10⁶ EID₅₀/mL), and because the virus has low concentration in its early stages, it cannot be detected easily. We have compared the sample measurements from our device with virus concentration data obtained from a RT-PCR (virus range: 10⁰-10⁴ EID₅₀/mL) and have identified an increasing voltage signal which corresponds to increasing virus concentration.

Oral intake of Lactobacillus rhamnosus M21 enhances the survival rate of mice lethally infected with influenza virus

BACKGROUND

Influenza viruses cause acute respiratory disease. Because of the high genetic variability of viruses, effective vaccines and antiviral agents are limited. Considering the fact that the site of influenza virus entry is the mucosa of the upper respiratory tract, probiotics that can enhance mucosal immunity as well as systemic immunity could be an important source of treatment against influenza infection.

METHODS

Mice were fed with Lactobacillus rhamnosus M21 or skim milk and were challenged with influenza virus. The resulting survival rate, lung inflammation, and changes in the cytokine and secretory immunoglobulin A (sIgA) levels were examined.

RESULTS

Because of infection (influenza virus), all the mice in the control group and 60% of the mice in the L. rhamnosus M21 group died; however, the remaining 40% of the mice fed with L. rhamnosus M21 survived the infection. Pneumonia was severe in the control group but moderate in the group treated with L. rhamnosus M21. Although there were no significant changes in the proinflammatory cytokines in the lung lysates of mice collected from both groups, levels of interferon-γ and interleukin-2, which are representative cytokines of type I helper T cells, were significantly increased in the L. rhamnosus M21-treated group. An increase in sIgA as well as the diminution of inflammatory cells in bronchoalveolar lavage fluid was also observed in the L. rhamnosus M21-treated group.

CONCLUSION

These results demonstrate that orally administered L. rhamnosus M21 activates humoral as well as cellular immune responses, conferring increased resistance to the host against influenza virus infection.

Epidemiological classification of infectious bronchitis virus isolated in Korea between 1986 and 1997

Forty Korean isolates and four reference strains of infectious bronchitis virus (IBV) were classified by reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis. Each Korean isolate was isolated from different types of commercial chicken flocks between 1986 and 1997. RFLP patterns of an amplified DNA fragment (1722 bp) containing the S1 gene of IBV digested by restriction enzyme HaeIII showed that the 40 Korean isolates were classified into five genotypes, I to V. Six of them belonged to genotype I which had the same HaeIII and XcmI cleavage patterns with Massachusetts type (H120 and M41) but the other four genotypes had a different HaeIII cleavage pattern from the four reference IBV strains used in this study. Genotype III seemed to be the major type as 29 of the 40 isolates belonged to this type which was consistently found in the chicken flocks since 1990. On the other hand, genotypes II, IV and V were found in the field only in 1986, 1995 and 1995, respectively. Five isolates selected from each of the five genotypes were inoculated into 1-day-old specific-pathogen-free chicks to evaluate their pathogenicity. Genotype III induced 50% mortality as well as severe renal urate deposition on the kidneys but the other four genotypes only showed respiratory distress at 1 to 2 days after inoculation. Live H120 vaccine protected chicks against challenge with isolates selected from genotype I, but not genotypes IV to V. A live KM91p120 strain selected from major genotype III did protect chicks against challenge with isolates from genotype III, in addition to other genotypes, including two recent isolates of genotypes IV and V.

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.

Evaluation of the efficacy of immunocastration vaccine composed of gonadotrophin-releasing hormone conjugated with Salmonella typhimurium flagellin in rats

Immunocastration is an alternative method to replace surgical castration that is commonly performed in domestic and pet animals. In this study, a new immunocastration vaccine was developed, and its efficacy was evaluated in male rats. Six tandem copies of gonadotrophin-releasing hormone (GnRH) peptide were genetically fused to Salmonella typhimurium flagellin fljB (STF2) that is a ligand of toll-like receptor 5 (TLR5). The recombinant STF2-GnRH protein expressed in Escherichia coli was used as the immunocastration vaccine. Sixteen male rats were equally assigned to four groups. Excluding the control rats, three groups were immunized with 100, 200 and 400 μg of the STF2-GnRH vaccine, respectively. All of the immunized rats developed significantly higher titres of antibodies to GnRH than the control rats. The size and weight of both testes and epididymides from the immunized rats were significantly smaller than those of the control rats. Testicular tissues in the immunized rats demonstrated atrophy of seminiferous tubules and decreased numbers of both spermatogonia and spermatocytes. These data indicate that the newly developed STF2-GnRH vaccine has a potent immunogenicity to GnRH and efficiently suppresses the development of testes in rats.

Selection of an antiviral RNA aptamer against hemagglutinin of the subtype H5 avian influenza virus

Avian influenza is an acute viral respiratory disease caused by RNA viruses of the family Orthomyxoviridae. The influenza A virus subtype H5 can cause severe illness and results in almost 100% mortality rate among livestock. Hemagglutinin (HA) present in the virus envelope plays an essential role in the initiation of viral infection. In this study, we investigated the efficacy of using HA as a target for antiviral therapy through nucleic acid aptamers. After purification of the receptor binding domain (HA1) of HA protein, activity of recombinant HA1 was confirmed by using hemagglutination assay. We selected RNA aptamer candidates after 15 rounds of iterative Systematic Evolution of Ligands by EXponential enrichment (SELEX) targeting the biologically active HA protein. The selected RNA aptamer HAS15-5, which specifically binds to HA1, exhibited significant antiviral efficacy according to the results of a hemagglutination inhibition assay using egg allantoic fluids harboring the virus. Thus, the RNA aptamer HAS15-5, which acts by blocking and inhibiting the receptor-binding domain of viral HA, can be developed as a novel antiviral agent against type H5 avian influenza virus.

Expression patterns of influenza virus receptors in the respiratory tracts of four species of poultry

The primary determinant of influenza virus infectivity is the type of linkage between sialic acid and oligosaccharides on the host cells. Hemagglutinin of avian influenza viruses preferentially binds to sialic acids linked to galactose by an α-2,3 linkage whereas hemagglutinin of human influenza viruses binds to sialic acids with an α-2,6 linkage. The distribution patterns of influenza receptors in the avian respiratory tracts are of particular interest because these are important for initial viral attachment, replication, and transmission to other species. In this study, we examined the distribution patterns of influenza receptors in the respiratory tract of chickens, ducks, pheasants, and quails because these species have been known to act as intermediate hosts in interspecies transmission. Lectin histochemistry was performed to detect receptor-bearing cells. Cell-specific distribution of the receptors was determined and expression densities were compared. We observed species-, site-, and cell-specific variations in receptor expression. In general, receptor expression was the highest in quails and lowest in ducks. Pheasants and quails had abundant expression of both types of receptors throughout the respiratory tract. These results indicate that pheasants and quails may play important roles as intermediate hosts for the generation of influenza viruses with pandemic potential.

Characterization of a novel live attenuated infectious bronchitis virus vaccine candidate derived from a Korean nephropathogenic strain

A nephropathogenic K2/01 strain of infectious bronchitis virus (IBV) was attenuated by 170 serial passages in embryonated chicken eggs for possible use as a future IBV vaccine strain. High-growth properties and narrow tissue tropisms (limited replication in respiratory tracts) were achieved by the adaptation process. Unlike the parent strain, the attenuated strain (K2p170) was safe in day-old specific-pathogen-free chicks since replication of the virus did not induce mortality and nephritis, and rarely induced histological changes in the trachea and kidney after intraocular administration. In day-old broilers, even though coarse spray administration of K2p170 induced clinical signs, ciliostasis, and histopathological lesions in the trachea and the kidney, they were all comparable to birds vaccinated with commercial H120 vaccine. Despite restriction of viral replication in the respiratory tract, K2p170 elicited the production of antiserum with a neutralization index of 4.5. K2p170 provided almost complete protection against both two distinct subgroups of Korean nephropathogenic strain (KM91-like and QX-like subgroup). Furthermore, K2p170 provided significantly greater cross-protection against two heterologous strains (Massachusetts and Korean respiratory strain) than those conferred by the commercial H120 vaccine. K2p170 also had no virulence reversion after five back passages in chickens. In conclusion, K2p170 exhibits a fine balance between attenuation and immunogenicity, possesses cross-protective efficacy, and merits further investigation as a potential live vaccine as an alternative means of protection against the recently emergent nephropathogenic IBV infection in many Eurasian countries.

Identification of single-nucleotide polymorphisms of the prion protein gene in sika deer (Cervus nippon laiouanus)

Polymorphisms of the prion protein gene (PRNP) have been detected in several cervid species. In order to confirm the genetic variations, this study examined the DNA sequences of the PRNP obtained from 33 captive sika deer (Cervus nippon laiouanus) in Korea. A total of three single-nucleotide polymorphisms (SNPs) at codons 100, 136 and 226 in the PRNP of the sika deer were identified. The polymorphic site located at codon 100 has not been reported. The SNPs detected at codons 100 and 226 induced amino acid substitutions. The SNP at codon 136 was a silent mutation that does not induce any amino acid change. The genotype and allele frequencies were determined for each of the SNPs.

Effects of Homologous and Heterologous Neuraminidase Vaccines in Chickens Against H5N1 Highly Pathogenic Avian Influenza

The 2004 Asian H5N1 epizootic outbreak indicates the urgent need for vaccines against highly pathogenic avian influenza (HPAI) virus. The manufacture of inactivated whole-virus vaccines from HPAI viruses by traditional methods is not feasible for safety reasons as well as technical issues. The low pathogenic avian influenza A/wild bird feces/CSM2/02 (H5N3) virus was used as a heterologous neuraminidase vaccine, and HPAI A/CK/Korea/ES/03 (H5N1) virus was used as a homologous neuraminidase vaccine. Protection efficacy of both vaccines was evaluated by clinical signs, mortality rates, and virus shedding from oropharynx and cloaca of vaccinated chickens after challenge with HPAI A/CK/Korea/ES/03 (H5N1) virus. One dose of 128 hemagglutinin (HA) homologous H5N1 vaccine induced 100% protection in mortality and prevented viral shedding completely after lethal dose virus challenge, whereas one dose of 64 HA unit of heterologous H5N3 vaccine only induced 50% protection in mortality, and it did not prevent viral shedding. However, two doses at a 3-wk interval of 64 HA unit of heterologous H5N3 vaccine as well as one dose of 1024 HA unit of heterologous H5N3 vaccine induced 100% survival rate and could prevent viral shedding completely. Furthermore, we could differentiate the sera of infected birds from those of vaccinated birds by indirect immunofluorescent antibody test. These results suggest that heterologous neuraminidase H5N3 vaccine could be a useful tool for the control of H5N1 HPAI epidemic in poultry.

Variations in the nucleocapsid protein gene of infectious bronchitis viruses isolated in Korea

Fourteen infectious bronchitis viruses (IBVs) were isolated in Korea between 2001 and 2003 from chickens suspected to be infected with IBVs. The nucleocapsid (N) protein genes of the various IBVs were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) and were cloned and sequenced, and the nucleotide and deduced amino acid sequences were compared with published sequences for non-Korean IBV strains. The Korean IBV isolates shared amino acid sequence similarity of between 89.2% (K203-02 and K1255-03) and 98.3% (K434-01 and K281-01) with each other and exhibited amino acid sequence similarity between 57.0% (K774-01 and V18/91) and 96.6% (K507-01 and JP8147) with non-Korean IBV strains. Phylogenetic analysis of the deduced N protein amino acid sequences resulted in the segregation of Korean IBV isolates into three different clusters, with cluster assignments differing for some of the isolates from those obtained with analysis of the S1 glycoprotein. Korean IBV isolates K069-01, K281-01, K434-01, K504-01, K774-01, K748-01, K044-02, K058-02, K161-02, K203-02, and K234-02 formed an independent cluster comprised only of Korean IBV isolates. Another Korean IBV isolate, K210-02, belonged to a cluster that included IBV strains isolated in USA, the Netherlands and China. Recent Korean IBV isolates K514-03 and K1255-03 grouped into a third distinct cluster related to a Chinese IBV strain. As deduced from phylogenetic analysis, some IBV isolates appear to have arisen from the recombination of IBV strains with different origins.

Molecular epidemiology of Newcastle disease viruses isolated in South Korea using sequencing of the fusion protein cleavage site region and phylogenetic relationships

The study, using sequence analysis and the phylogenetic relationship of the fusion protein gene, divided the Korean epizootic isolates of Newcastle disease virus (NDV) into several lineages to determine the molecular epidemiology of the virus. A 695 base pair fragment was amplified by polymerase chain reaction between matrix protein gene and fusion protein gene of 30 Korean NDV isolates, which were isolated from field outbreaks of Newcastle disease between 1949 and 2002. All isolates showed the amino acid sequence 112R-R-Q/R-K-R116 at the C-terminus of the F2 protein and phenylalanine (F) at the N-terminus of the F1 protein, residue 117. These amino acid sequences were identical to a known virulent motif. The region of the F gene between nucleotides 47 and 435 was compared by phylogenetic analysis. Based on nucleotide sequence, the Korean NDV isolates belonged to genotype III, V, VI and VII corresponding to isolates in 1949, 1982 to 1984, 1988 to 1997, and 1995 to 2002, respectively. These data showed that genotypes of five Korean Newcastle disease epizootics had replaced each other serially (III, V, VI and VII) in chronological order. Further, the five Korean Newcastle disease epizootics were closely related with the Newcastle disease panzootics or Newcastle disease epizootics in other countries. Present study showed that the Korean genotype V isolated before 1984 was related with European Newcastle disease epizootics in the 1970s, whereas the Korean genotypes VI and VII isolated after 1988 were more closely related with Far East Newcastle disease epizootics, especially Newcastle disease epizootics in Japan, Taiwan and China. Since 1988, the genotypes VI and VII of Far East origin were dominant in South Korea. That might be due to the increased trade of agricultural products including poultry among Far East Asian countries.

Androgen receptor: structural domains and functional dynamics after ligand-receptor interaction

Androgens are C-19 steroids secreted primarily from the testes and adrenals that play a critical role in reproduction. Reproductive functions of androgens are mediated through coordination of diverse physiological processes ranging from brain functions to specific cell proliferation and apoptosis. At the molecular level, most of these regulatory influences are exerted by altered expression of appropriate genes by the androgen receptor (AR), a member of the nuclear receptor (NR) superfamily. The unliganded AR is a cytoplasmic protein and, upon ligand binding, it translocates into the nucleus. Thereafter, in conjunction with other transcription factors and coactivators, the AR influences transcription of target genes through a multistep process that includes its clustering in a subnuclear compartment. Here, we describe the genomic organization of the AR, the role of individual structural domains in specific AR function, and the influence of agonistic/antagonistic ligands in the intracellular movement of the receptor. We also show that the AR is capable of undergoing multiple rounds of nucleocytoplasmic recycling after ligand binding and dissociation. Xenobiotic ligands, considered as selective androgen receptor modulators (SARMs), can modulate AR activity by inhibiting either its nuclear translocation or its subnuclear clustering and subsequent transactivation function.

Prevalence of porcine proliferative enteropathy and its control with tylosin in Korea

Porcine proliferative enteropathy(PPE) is an enteric disease been caused by Lawsonia intracellularis. It has become one of the critical problems in the pig industry. To investigate the prevalence of PPE in Korea, serum samples of 828 pigs from 65 herds were tested using indirect immunofluorescence antibody technique(IFA). The infection rate in individual pigs varied from 44 to 69%, whereas 100% in pig farms. The infection frequency was 57, 44.9, and 59.4% according to age respectively. Administration of tylosin in feed at a concentration of 110 ppm for 14 days reduced the infection rate of the farms. These data indicated that the high prevalence of PPE may be controlled by tylosin.

Dehydroepiandrosterone sulfotransferase gene induction by bile acid activated farnesoid X receptor

Dehydroepiandrosterone sulfotransferase (STD) is a hydroxysteroid sulfo-conjugating enzyme with preferential substrate specificity for C-19 androgenic steroids and C-24 bile acids. STD is primarily expressed in the liver, intestine and adrenal cortex. Earlier studies have shown that androgens inhibit the rat Std promoter function through a negative androgen response region located between -235 and -310 base pair positions (Song, C. S., Jung, M. H., Kim, S. C., Hassan, T., Roy, A. K., and Chatterjee, B. (1998) J. Biol. Chem. 273, 21856-21866). Here we report that the primary bile acid chenodeoxycholic acid (CDCA) also acts as an important regulator of the Std gene promoter. CDCA is a potent inducer of the Std gene, and its inducing effect is mediated through the bile acid-activated farnesoid X receptor (FXR), a recently characterized member of the nuclear receptor superfamily. The ligand-activated FXR acts as a heterodimer with the 9-cis-retinoic acid receptor (RXR) and regulates the Std gene by binding to an upstream region at base pair positions -169 to -193. This specific binding region was initially identified by bile acid responsiveness of the progressively deleted forms of the Std promoter in transfected HepG2 hepatoma and enterocyte-like Caco-2 cells. Subsequently, the precise RXR/FXR binding position was established by protein-DNA interaction using in vitro footprinting and electrophoretic mobility shift analyses. Unlike all other previously characterized FXR target genes, which contain an inverted repeat (IR) of the consensus hexanucleotide half-site (A/G)G(G/T)TCA with a single nucleotide spacer (IR-1), the bile acid response element of the Std promoter does not contain any spacer between the two hexanucleotide repeats (IR-0). A promoter-reporter construct carrying three tandem copies of the IR-0 containing -169/-193 element, linked to a minimal thymidine kinase promoter, can be stimulated more than 70-fold in transfected Caco-2 cells upon CDCA treatment. Autoregulation of the STD gene by its bile acid substrate may provide an important contributing role in the enterohepatic bile acid metabolism and cholesterol homeostasis.

Induction of immune responses to glycoprotein gD of Aujeszky's disease virus with DNA immunization

In an attempt to produce a DNA vaccine to prevent Aujeszky's disease, the induction of immune responses against Aujeszky's disease virus (ADV) gD was investigated in mice. The plasmid was constructed by placing ADV gD gene downstream of murine cytomegalovirus immediate early promoter of expression vector pMYK, which was injected twice on the skin of mice by using a gene-gun. All mice showed neutralizing antibodies against ADV gD at 4 weeks after immunization. The induction of cytotoxic T lymphocytes and splenic natural killer cells was also observed at 6 weeks post immunization. These results indicate that ADV gD gene in the form of DNA vaccine may induce specific as well as non-specific immune responses in vivo.

Dynamics of intracellular movement and nucleocytoplasmic recycling of the ligand-activated androgen receptor in living cells

An expression construct containing the cDNA encoding a modified aequorea green fluorescent protein (GFP) ligated to the 5'-end of the rat androgen receptor (AR) cDNA (GFP-AR) was used to study the intracellular dynamics of the receptor movement in living cells. In three different cell lines, ie. PC3, HeLa, and COS1, unliganded GFP-AR was seen mostly in the cytoplasm and rapidly (within 15-60 min) moved to the nuclear compartment after androgen treatment. Upon androgen withdrawal, the labeled AR migrated back to the cytoplasmic compartment and maintained its ability to reenter the nucleus on subsequent exposure to androgen. Under the condition of inhibited protein synthesis by cycloheximide (50 microg/ml), at least four rounds of receptor recycling after androgen treatment and withdrawal were recorded. Two nonandrogenic hormones, 17beta-estradiol and progesterone at higher concentrations (10(-7)/10(-6) M), were able to both transactivate the AR-responsive promoter and translocate the GFP-AR into the nucleus. Similarly, antiandrogenic ligands, cyproterone acetate and casodex, were also capable of translocating the cytoplasmic AR into the nucleus albeit at a slower rate than the androgen 5alpha-dihydrotestosterone (DHT). All AR ligands with transactivation potential, including the mixed agonist/antagonist cyproterone acetate, caused translocation of the GFP-AR into a subnuclear compartment indicated by its punctate intranuclear distribution. However, translocation caused by casodex, a pure antagonist, resulted in a homogeneous nuclear distribution. Subsequent exposure of the casodex-treated cell to DHT rapidly (15-30 min) altered the homogeneous to punctate distribution of the already translocated nuclear AR. When transported into the nucleus either by casodex or by DHT, GFP-AR was resistant to 2 M NaCl extraction, indicating that the homogeneously distributed AR is also associated with the nuclear matrix. Taken together, these results demonstrate that AR requires ligand activation for its nuclear translocation where occupancy by only agonists and partial agonists can direct it to a potentially functional subnuclear location and that one receptor molecule can undertake multiple rounds of hormonal signaling; this indicates that ligand dissociation/inactivation rather than receptor degradation may play a critical role in terminating hormone action.

Pseudochylous pleural effusion with fat-fluid levels: report of six cases

The authors report the clinical and computed tomographic (CT) findings in six patients with chyliform pleural effusion. All six patients had a medical history of pleurisy before presentation; five of them had tuberculous pleural effusion. The CT scans of all six patients showed variable amounts of pleural fluid collection with a layering of fat at the nondependent site.

Sequence analysis of the hemagglutinin gene of H9N2 Korean avian influenza viruses and assessment of the pathogenic potential of isolate MS96

Sequence analysis of the hemagglutinin (HA) gene of five Korean H9N2 avian influenza virus (AIV) isolates showed that these viruses were closely related and possibly came from the same source. Phylogenetic analysis of the HA1 subunit of H9 subtype isolates revealed that Korean AIV isolates were different from isolates from the poultry markets in Hong Kong in 1997. None of the Korean AIVs had multiple basic amino acids at the HA cleavage site that confer high pathogenicity to some H5 and H7 AIVs. Phylogenetic analysis of the nucleoprotein and matrix gene demonstrated that Korean isolates cluster with Eurasian origin AIVs. The pathogenic potential of one of the isolates (MS96) was assessed after several passages in 14-day-old embryonated chicken eggs (ECE). Fourteen-day-old ECE derivatives of MS96 showed increased HA titer and embryo mortality in eggs; this was apparent after the third passage in 14-day-old ECE. Sequence analysis of the cleavage site of MS96 after the third and tenth passages in 14-day-old ECE revealed no changes in the amino acid sequence. The pathogenicity of MS96 after the tenth passage in 14-day-old eggs (MS96p10(ECE14)) was tested with 4-wk-old specific-pathogen-free chickens. The 14-day-old derivative, MS96p10(ECE14), showed wider tissue tropism and induced more severe clinical signs than the parent virus. Furthermore, after intranasal inoculation of 86-wk-old broiler breeders and 30-wk-old layers, the MS96p10(ECE14) derivative induced more severe signs of depression than the parent virus as well as a transient drop in egg production.

Gastric adenoma with atypical appearance: findings on double-contrast barium study with histopathologic correlation

BACKGROUND

To describe the radiologic findings of nonpolypoid gastric adenomas and to correlate them with pathologic findings.

METHODS

During a 9-year period, we reviewed 49 pure gastric adenomas in 43 patients with positive radiologic findings. Of these adenomas, seven with atypical polypoid appearance were retrospectively included in the study. We reviewed these findings with double-contrast barium study and correlated them with the pathologic findings.

RESULTS

Of seven nonpolypoid adenomas, four were depressed and three were flat at pathologic examination. All were diagnosed as early gastric carcinoma (five as type IIc, one as type IIb, one as type IIa + IIc) in upper gastrointestinal series. Three were located in the gastric angle, two in the lower body, and two in the antrum. Size ranged from 10 mm to approximately 25 mm (mean = 15 mm). Six lesions had nodular surface and five had convergency of the mucosal folds. A shallow depressed area was seen in six lesions.

CONCLUSIONS

A considerable proportion of gastric adenomas presents as a depressed or flat lesion on double-contrast barium study because of histologic characteristics of decreased subjacent mucosa. Because the nonpolypoid adenoma has a greater potentional for malignancy, more precaution is needed during the follow-up of this uncommon lesion.

Age-dependent increase of heme oxygenase-1 gene expression in the liver mediated by NFkappaB

Heme, the iron-porphyrin coordination complex, released from the degradation of hemoproteins, is a strong prooxidant. It is enzymatically degraded by heme oxygenase to free iron, carbon monoxide and biliverdin. Biliverdin and its reduced metabolite bilirubin are two potent physiological antioxidants. Here we show a progressive increase of steady-state levels of the mRNA encoding the inducible isoform of this enzyme (heme oxygenase-1) in the rat liver during aging. We had previously reported that aging is associated with increased activation of the nuclear factor kappaB (NFkappaB). We now provide evidence to establish that overexpression of NFkappaB in transfected liver-derived HepG2 cells can cause a marked induction of the endogenous heme oxygenase-1 (HO-1) mRNA and activation of the cotransfected HO-1 gene promoter. Taken together, these results support the conclusion that enhanced oxidative stress during aging is accompanied by compensatory induction of the antioxidant enzyme HO-1 through activation of the NFkappaB pathway.

Negative regulation of the androgen receptor gene promoter by NFI and an adjacently located multiprotein-binding site

The upstream promoter of the rat androgen receptor (AR) gene contains a strong negative regulatory region located at the -388 to -340 nucleotide position. The distal part (-388/-373) of this regulatory region binds NFI, a ubiquitous transcription factor, while the proximal portion (-372/-340) contains an overlapping binding site for two nuclear proteins. This composite regulatory region (-388/-340) was initially defined by deoxyribonuclease I footprinting as the continuous stretch of a nuclease-protected site. NFI specificity of the distal portion (-388/-373) of the footprint was established through cross-competition in electrophoretic mobility shift assay (EMSA) using the well characterized NFI element of the adenovirus major late promoter and by immunoreactivity to the NFI antibody. EMSA with oligonucleotide duplexes corresponding to the proximal domain (-372/-340) indicated multiple retarded bands with at least two major DNA-protein complexes. Further analysis with truncated oligonucleotide duplexes showed that these two major proteins bind to this domain in an overlapping manner. Within this overlapping area, the position spanning -359 to -347 is essential for the formation of either of these two complexes. Substitution of four G with T residues in the overlapping area totally abolished all protein binding at the downstream -372/-340 site. Point mutations that abolish specific binding at either the NFI or immediately downstream multiprotein-binding site caused about a 10-fold increase in AR promoter activity in transfected HepG2 cells. Double mutation involving both the NFI and proximal overlapping protein-binding sites failed to cause any additional increase in promoter function. From these results we conclude that the AR promoter contains a composite negative regulatory region at -388/-340, and the repressor function may involve a coordinate interaction between NFI and at least two other nuclear factors.

Ribozyme-mediated cleavage of the estrogen receptor messenger RNA and inhibition of receptor function in target cells

Estrogen receptor (ER) functions as a ligand-activated transcription factor for estrogen-regulated genes. Because of the critical role of the ER in the proliferation of certain estrogen-dependent cancer cell types such as the mammary tumor, inhibitors of estrogen action at the level of receptor function are of major clinical interest. Here we describe developments of two ribozymes that can selectively degrade the human ER mRNA and inhibit trans-activation of an artificial promoter containing the estrogen response element. Two ribozymes, designated RZ-1 and RZ-2, cleave the human ER alpha mRNA at nucleotide positions +956 and +889, respectively. These cleavage sites lie within the coding sequence for the DNA-binding domain of the receptor protein. Both RZ-1 and RZ-2 were also effective in inhibiting the progression of quiescent MCF-7 breast cancer cells to the S phase of the cell cycle after their exposure to 17beta-estradiol (10(-9) M). These results provide a new avenue for inhibition of estrogen action by selective mRNA degradation with its potential therapeutic application through targeted gene delivery vectors.

Dysplastic nodules of the liver: imaging findings

BACKGROUND

To verify characteristic features of hepatic dysplastic nodules at different imaging modalities.

METHODS

Twenty-eight patients with 37 dysplastic nodules of the liver (0.8-3.0 cm) underwent sonography (28 patients), computed tomography (CT; 24 patients), magnetic resonance (MR; 11 patients), and angiography (12 patients). Each nodule was analyzed for echogenicity, attenuation, signal intensity, and vascularity.

RESULTS

Echogenicity of nodules was high in 16 (43%), homogeneous in two (6%), and low in 19 (51%) of 37 nodules. Attenuation of nodules was high in one (7%), homogeneous in four (26%), and low in 10 (67%) of 15 nodules on the arterial-phase CT images; homogeneous in five (33%) and low in 10 (67%) of 15 nodules on the portal-phase CT images; and high in four (17%), homogeneous in six (26%), and low in 13 (57%) of 23 nodules on the delayed-phase CT images. Signal intensity of nodules was high in 15 (94%) and homogeneous in one (6%) of 16 nodules on T1-weighted MR images and was homogeneous in seven (44%) and low in nine (56%) of 16 nodules on T2-weighted MR images. Vascularity of nodules was avascular in 14 (88%) and slightly vascular in two (12%) of 16 nodules.

CONCLUSIONS

Hepatic dysplastic nodules show diverse imaging characteristics with different imaging techniques; however, common imaging findings of hepatic dysplastic nodules are low echo, low attenuation, and high, low, or homogeneous intensity on T1- and T2-weighted MR, and avascularity.

Auditory and facial nerve dysfunction in patients with hemifacial microsomia

BACKGROUND

Hemifacial microsomia (HFM) is a common craniofacial disorder characterized by a wide spectrum of anomalies, including conductive hearing loss due to external and middle ear deformities. However, the prevalence of sensorineural hearing loss (SNHL) as well as facial nerve dysfunction is underappreciated.

OBJECTIVE

To determine the frequency of auditory and facial nerve dysfunction and its relationship to more severe forms of bilateral HFM.

DESIGN

Retrospective medical record review to characterize the clinical severity of HFM and the prevalence and nature of the associated auditory and facial nerve dysfunction.

SETTING

Center for Craniofacial Anomalies at the University of California, San Francisco, Medical Center.

PATIENTS

Ninety-nine pediatric patients with HFM evaluated at the University of California, San Francisco, Medical Center.

MAIN OUTCOME MEASURES

The prevalence of SNHL and facial nerve dysfunction in this patient population and any associations between these 2 characteristics.

RESULTS

Hearing loss was present in 74 (75%) of 99 patients, with a conductive component in 73 patients. Sensorineural hearing loss was present in 11 patients ( 11%), with mixed hearing loss in most patients. Fourteen patients required rehabilitation with auditory amplification. Nearly a quarter of the patients (22 [22%] of 99) had facial nerve dysfunction, but only 1 patient had facial palsy on the same side as the SNHL. There was a statistically significant association between having auricular abnormalities and conductive hearing loss or SNHL (P = .30 and .80, respectively). However, there was no statistically significant association between bilateral HFM and the occurrence of either SNHL or facial paralysis, nor was there an association between auditory and facial nerve dysfunction.

CONCLUSIONS

Sensorineural hearing loss and facial nerve dysfunction are common in HFM. These findings have important implications in the treatment of patients with HFM.

Catalytic cleavage of the androgen receptor messenger RNA and functional inhibition of androgen receptor activity by a hammerhead ribozyme

Androgen receptor (AR) plays a key role in cell growth both in the normal prostate and in prostate cancer. Androgen ablation and prolonged antiandrogen therapy can give rise to AR-dependent prostate tumors, which nonetheless can grow in the androgen-deprived milieu. Here we describe the ribozyme approach to selectively degrading the AR mRNA and thereby inhibiting AR function. A trans-acting hammerhead ribozyme was designed to cleave the rat AR mRNA at the position +1827/ 1828, a region predicted to be minimally involved in generating stable secondary structures. Using AR mRNA fragments as substrates, it was established that this ribozyme can specifically cleave the RNA target in a sequence-specific manner. Kinetic experiments determined a Km for the substrate of 77 nM and a kcat/Km value of 1.8 x 10(7) M(-1) x min(-1), suggesting a catalytic efficiency similar to that of protein enzymes such as the relatively nonspecific ribonuclease A and a sequence-specific endonuclease EcoRI. Transient cotransfections of prostate-derived PC3 cells with three plasmids, an AR-inducible chloramphenicol acetyltransferase (CAT) reporter, an AR expression vector, and a ribozyme expression vector, showed that the ribozyme was capable of reducing the functional activity of AR. At an equimolar ratio of the AR expression plasmid to ribozyme expression plasmid, androgen-inducible CAT activity was inhibited 70%. Similar extents of inhibition were also observed at the cellular mRNA level using ribonuclease protection assays, indicating that the ribozyme functioned as an AR mRNA cleaving enzyme in cellulo. Immunocytochemical examination revealed a decline of AR immunoreactivity in ribozyme-transfected cells. In addition, no morphologically detectable cellular abnormalities were associated with ribozyme expression, indicating the absence of deleterious side effects. These results offer a new avenue for the control of AR function and cell growth, especially in the case of androgen-resistant, but AR-dependent, prostate cancer cells.

Tissue-specific and androgen-repressible regulation of the rat dehydroepiandrosterone sulfotransferase gene promoter

Dehydroepiandrosterone sulfotransferase (Std) catalyzes sulfonation of androgenic steroids and certain aromatic procarcinogens. In rats, this enzyme is selectively expressed in the liver, and its expression is strongly repressed by androgens. DNase I footprinting and electrophoretic mobility shift analyses revealed two hepatocyte nuclear factor-1 (HNF1), three CCAAT/enhancer-binding protein (C/EBP), and one consensus palindromic thyroid hormone response elements within the first 215 base pairs (bp) of the promoter sequence of rat Std. This promoter is normally inactive in fibroblast-derived NIH 3T3 cells. However, overexpression of HNF1 and C/EBP resulted in synergistic activation of the Std promoter in this cell type, indicating essential roles of these two trans-regulators in liver-selective expression of the rat Std gene. On the other hand, point mutations at any one of five cis elements proximal to the -215 bp region markedly reduced reporter gene expression, suggesting that all of these sites are important for overall promoter function. Androgenic repression of the Std gene in rat liver can be recapitulated in androgen receptor (AR)-negative HepG2 hepatoma cells after cotransfection with an AR expression plasmid. Functional assay of a nested set of 5'-deleted promoters mapped the negative androgen response region between positions -235 and -310. Antibody supershift and oligonucleotide competition identified three OCT-1 and two C/EBP elements between bp -231 and -292. An additional OCT-1 site was found to overlap with a C/EBP element at the -262/-252 position. Mutational inactivation of any one of five cis elements within the -231/-292 region abolished negative androgen response. However, none of these cis elements showed DNase I protection by recombinant AR in footprinting assay, suggesting the absence of a direct AR-DNA interaction. Thus, these studies on rat Std promoter function indicate that (i) HNF1 and C/EBP are responsible for liver specificity of the rat Std gene; (ii) androgenic repression of the gene requires the presence of all of the OCT-1 and C/EBP elements between positions -231 and -292; and (iii) AR may exert its negative regulatory effect indirectly through transcriptional interference of OCT-1 and C/EBP rather than through a direct DNA-AR interaction.

A rapid and reliable PCR-based assay for gene transmission and sex determination in newborn transgenic mice

This article describes a reliable and rapid method for simultaneous detection of a transgene and sex determination in the newborn mouse pups by PCR using three sets of primers in a single reaction. One set of sense/antisense primers is used to amplify the experimental transgene (androgen receptor gene in this case), the second set for the mouse Y-chromosome-specific SRY gene, and the third set for the beta subunit of the thyroid stimulating hormone (TSH beta), an internal control. This procedure allowed us to promptly analyze pups born from transgenic founders carrying the androgen receptor transgene and, at the same time, establish the sex of the animals. The method is simple, rapid and highly reproducible.

Induction of protective immunity in chickens vaccinated with infectious bronchitis virus S1 glycoprotein expressed by a recombinant baculovirus

A recombinant baculovirus containing the S1 glycoprotein gene of the virulent nephropathogenic KM91 strain of infectious bronchitis virus (IBV) was constructed in order to investigate protective immunity in vaccinated chickens. Results from the protection test were evaluated by re-isolation of virus from the kidneys and tracheas of vaccinated chickens after challenge with strain KM91. After three immunizations, the recombinant S1 (rS1) glycoprotein induced 50% protection of the kidney, whilst inactivated KM91 induced 88% and 50% protection of the kidney and trachea, respectively. In chickens primed with the attenuated H120 vaccine strain, which is heterologous to KM91, the rS1 glycoprotein induced 83% protection of the kidney after two immunizations. Haemagglutination-inhibition titres were also increased in chickens immunized with the rS1 glycoprotein after three immunizations, and significantly higher titres were detected after challenge. These data indicate that the expressed rS1 glycoprotein alone can induce a protective immune response as well as an antibody response.

Inhibition of androgen action by dehydroepiandrosterone sulfotransferase transfected in PC-3 prostate cancer cells

Age-dependent loss of androgen sensitivity of the rat liver is associated with a marked increase in dehydroepiandrosterone/hydroxysteroid sulfotransferase (rStd) activity. Sulfonated steroid hormones are known to be ineffective in binding receptor proteins. These observations suggest that intracellular androgen sulfonation can physiologically influence androgen action. We have examined the inhibitory effect of rStd on androgen action in the human prostate cancer-derived PC-3 cells transfected with the rat androgen receptor (AR) expression plasmid and two androgen-responsive promoter reporter constructs (murine mammary tumor long-terminal repeat ligated to chloramphenicol acetyltransferase (CAT) gene and rat probasin androgen response element (ARE) ligated to firefly luciferase (LUC) gene). These transfected cells were dependent on 5alpha-dihydrotestosterone (DHT) for the activation of both reporter genes and showed about a 200- and a 800-fold increase of CAT and LUC activity, respectively, at 10(-10) M DHT over the no-hormone control. Expression of the sulfonating enzyme in this cell transfection system via the rStd expression plasmid caused a dose-dependent decline in the reporter activity with approximately 90% inhibition of androgen action at a rStd:AR plasmid ratio of 100. From these results we conclude that irrespective of a high level of AR, changes in the Std expression can markedly alter the androgen sensitivity of target cells.

Detection and classification of infectious bronchitis viruses isolated in Korea by dot-immunoblotting assay using monoclonal antibodies

Dot-immunoblotting assay (DIA) using five monoclonal antibodies (MAbs) to infectious bronchitis virus (IBV) was used to detect and classify the viruses propagated in embryonated chicken eggs. Using a group-specific MAb 3F5, 10 reference strains and 12 Korean isolates of IBV were successfully detected by DIA, and the lowest virus titer of IBV detected by DIA was approximately less than 10(3.8) mean embryo infective dose/ml. For evaluating the diagnostic efficiency, DIA was compared with the conventional infectious bronchitis (IB) diagnostic method. IBV antigens in allantoic fluid from embryonated eggs inoculated with IB-suspected field samples were specifically detected by DIA within only one or two egg passages, whereas the conventional embryonated egg inoculation method required four to seven egg passages for confirming IBV infection. These results indicated that DIA could significantly reduce time and cost for IB diagnosis. For examining the possibility of classifying IBV by DIA, four strain-specific MAbs, 3A4, 2A3, 6F7, and 2C6, were used. According to the MAb reacting patterns to the IBV antigens, the 10 IBV reference strains were classified into six groups; seven strains belonged to three different groups, and the other three strains each belonged to an individual group. In the case of 12 Korean isolates of IBV, they were classified in six groups. Among the six groups, the MAb reacting patterns of three groups matched those of the IBV reference strains, but the others did not. These data suggest that at least three variant serotypes of IBV exist in Korea.

Effect of Ca2+ channel blockers, external Ca2+ and phospholipase A2 inhibitors on t-butylhydroperoxide-induced lipid peroxidation and toxicity in rat liver slices

OBJECTIVES

This study was undertaken to examine the effect of oxidant on lipid peroxidation and lethal cell injury in rat liver slices.

METHODS

t-Butylhydroperoxide (t-BHP) was employed as a model of an oxidant. The lipid peroxidation and lethal cell injury were estimated by measuring the formation of malondialdehyde (MDA) and lactate dehydrogenase (LDH) release, respectively.

RESULTS

t-BHP increased lipid peroxidation and LDH release in a dose-dependent manner over concentrations of 0.5-10 mM. t-BHP-induced lipid peroxidation was completely prevented by an antioxidant, N,N-diphenyl-p-phenylenediamine (DPPD), but LDH release was partially decreased. Both t-BHP-induced lipid peroxidation and LDH release were significantly protected by iron chelator, deferoxamine, sulfhydryl reducing agent, dithiothreitol and glutathione. Ca2+ channel blockers, verapamil, diltiazem and nifedipine exerted a significant protective effect against t-BHP-induced lipid peroxidation and LDH release. By contrast, addition of external Ca2+ chelator, ethylene glycol bis(b-aminoethyl ether)-N,N-tetraacetic acid (EGTA) did not alter t-BHP-induced lipid peroxidation, whereas t-BHP-induced lethal cell injury was significantly prevented. Phospholipase A2 (PLA2) inhibitors, mepacrine and butacaine produced a partial protective effect.

CONCLUSIONS

These results suggest that t-BHP induces cell injury by lipid peroxidation-dependent and -independent mechanisms which can be partially prevented by Ca2+ channel blockers and PLA2 inhibitors.

Characterization and expression of the Marek's disease virus serotype 2 glycoprotein E in recombinant baculovirus-infected cells: initial analysis of its DNA sequence and antigenic properties

In Marek's disease virus (MDV) serotype 2 (MDV2) genome, a gene equivalent to the glycoprotein E (gE) of other alphaherpesviruses was identified and sequenced. The primary translation product comprises 488 amino acids with a M(r) of 54.3 kDa. The predicted amino acid sequence possesses several characteristics typical of membrane glycoproteins, including a N-terminal hydrophobic signal sequence, C-terminal transmembrane and cytoplasmic domains, and extra-cellular region containing four potential N-linked glycosylation sites. Compared with other MDV serotypes, MDV2 gE showed 47.3% identity with MDV1 gE, and 38.9% identity with HVT gE at the amino acid level. In transcriptional analyses, a 2.0 kb mRNA which starts between 65 and 86 bps upstream of the potential translational initiation codon of gE was identified as the gE-specific transcript. By a recombinant baculovirus, this potential gE coding region was expressed as several specific products from 66 to 72 kDa. These products were susceptible to tunicamycin treatment, indicating that they were glycoprotein in nature. Further, the expressed gE reacted with all chicken-antisera raised to each of the three serotypes of MDV (strains GA, SB-1, and FC126), suggesting that gE is expressed by all three serotypes of MDV in infected cells and conserves common antigenic epitope(s) beyond those that are serotype specific.

Functional role of a conformationally flexible homopurine/homopyrimidine domain of the androgen receptor gene promoter interacting with Sp1 and a pyrimidine single strand DNA-binding protein

The androgen receptor (AR) gene promoter does not contain the TATA or CAAT box, but it contains a long (approximately 90-bp) homopurine/homopyrimidine (pur/ pyr) stretch immediately upstream of the Sp1-binding GC box site. This pur-pyr stretch is conserved at the same proximal position in the rat, mouse, and human AR gene promoters. Mutation of this region results in a 3-fold decline in promoter activity, indicating an important regulatory function. Examination of the conformational state of the AR pur/pyr region with the single-strand-specific S1 nuclease showed that it is capable of forming a non-B DNA structure involving unpaired single strands. Fine mapping of the S1-sensitive site revealed an unsymmetric cleavage pattern indicative of an intramolecular triple helical H-form DNA conformation. Electrophoretic mobility shift analyses showed that the pur/pyr region of the AR promoter can bind a novel pyrimidine single-strand-specific protein (ssPyrBF) and also a double-strand DNA-binding protein. Both oligonucleotide cross-competition and antibody supershift experiments established that the double-strand binding protein is equivalent to Sp1. Deoxyribonuclease I (DNase I) footprinting analysis showed multiple Sp1-binding to the pur/pyr site and a weaker Sp1 interaction to this region compared with the adjacently located GC box, where Sp1 functions to recruit the TFIID complex. These results suggest that the pur/pyr domain of the AR gene can serve to attract additional Sp1 molecules when it exists in the double-stranded B-DNA conformation. However, binding of ssPyrBF and the resultant stabilization of the non-B DNA structure is expected to prevent its interaction with Sp1. We speculate that in the TATA-less AR gene promoter, multiple weak Sp1 sites at the pur/pyr region adjacent to the GC box can provide a readily available source of this transcription factor to the functional GC box, thereby facilitating the assembly of the initiation complex.

Targeted overexpression of androgen receptor with a liver-specific promoter in transgenic mice

The rodent liver displays marked age- and sex-dependent changes in androgen sensitivity due to the sexually dimorphic and temporally programmed expression of the androgen receptor (AR) gene. We have altered this normal phenotype by constitutive overexpression of the rat AR transgene in the mouse liver by targeting it via the human phenylalanine hydroxylase (hPAH) gene promoter. These transgenic animals in their heterozygous state produce an approximately 30-fold higher level of the AR in the liver as compared with the nontransgenic control. Androgen inactivation via sulfonation of the hormone by dehydroepiandrosterone sulfotransferase (DST), an androgen-repressible enzyme, also contributes to the age- and sex-dependent regulation of hepatic androgen sensitivity. DST has a broad range of substrate specificity and is responsible for the age- and sex-specific activation of certain polycyclic aromatic hepatocarcinogens as well, by converting them to electrophilic sulfonated derivatives. In the transgenic female, the hepatic expression of DST was approximately 4-fold lower than in normal females, a level comparable to that in normal males. The hPAH-AR mice will serve as a valuable model for studying the sex- and age-invariant expression of liver-specific genes, particularly those involved in the activation of environmental hepatocarcinogens such as the aromatic hydrocarbons.

The evolutionary tangle of aging, sex, and reproduction and an experimental approach to its molecular dissection

Exchange of genetic materials by two individual members of the same species is considered to be the origin of primitive sex. During evolution, this primitive form of molecular sex has been transformed into a complex biological function involving specialized sexual structures and multiple hormonal interactions. Development and maintenance of these reproductive structures are also dependent on hormones and hormone receptors. Furthermore, reproductive specialization in higher forms of life has led to customized species-specific rates of aging and life-span potentials that are commensurate with the reproductive needs of the particular type of organism. Because of this reproductive imposition on aging of the organism, temporal regulation of the hormone response is a significant component of the genetics of aging. We have observed a marked age-dependent alteration in the hepatic expression of the rat androgen receptor (rAR) gene. Among the large number of transcription factors that control the rAR gene, at least three appear to participate in its age-dependent regulation. Two of these are positively acting and yet/to be characterized transcription factors, while the third is a negative regulator the nuclear factor kappa B (NF-kappa B). NF-kappa B is the major trans-regulator for genes involved in the immune response, inflammation, and oxidative stress. Involvement of NF-kB in the modulation of both oxidative stress and sex function provides the first example of a common molecular link between sex and aging.

Molecular cloning and sequence analysis of the rat liver carnitine octanoyltransferase cDNA, its natural gene and the gene promoter

The full-length cDNA and the natural gene for rat peroxisomal carnitine octanoyltransferase (COT) have been isolated and sequenced. The 2681 bp long cDNA contains an open reading frame for 613 amino acids, resulting in a protein with a deduced molecular weight of 70,301, and a C-terminal peroxisomal targeting sequence (Ala-His-Leu). The isolated COT cDNA has 51 bp of the 5' untranslated region (UTR), 791 bp of 3' UTR, two putative polyadenylation sites, and a poly(A19-23) tail. Screening of a rat genomic DNA library in the lambda phage with the COT cDNA probe resulted in the isolation of seven overlapping clones, together containing the complete COT gene with seventeen exons. All of the exon-intron boundary sequences conform to the GT-AG rule. The COT gene appears to spread over 40 to 60 kbp region of the rat genome. The transcription initiation site of the COT gene was determined through primer extension, and the promoter sequence up to the position -1140 was established. The promoter lacks the canonical TATA box and a promoter-reporter construct containing the sequence encompassing -1140 to +84 base positions and the firefly luciferase reporter cDNA yielded about 100-fold increase in promoter activity in transfected hepatoma cells. Some of the consensus sequences for putative cis elements present in the promoter sequence are: the two CCAAT motifs for CTF/NF1/CBP binding (at -284 and -93), two GC boxes for Sp1 binding (at -160 and -68), two AP2 sites (at -359 and -25), a half site (TGACCT) for the peroxisome proliferator activated receptor (PPAR) binding at -737 within a partial palindromic sequence region. Potential regulatory elements, such as several palindromes and repeat motifs for five different sequence segments, are also identified.

[Study of anti-cerebral thromboembolism injection's activity on experimental arterial thrombosis and its therapeutical mechanism]

Anti-Cerebral Thromboembolism Injection (ACTI), applied intravenously in Cattaneo's animal model of arterial thrombosis, could significantly reduce the weight of thrombus, blood viscosities, plasma TXB2 level and delay the prothrombin time, compared to control group (P < 0.05). From this trial, it was indicated that ACTI's reducing thrombosis action was the result of inhibiting aggregation and releasing of platelets through reducing whole blood viscosities and TXB2 level.

Regulation of androgen action by receptor gene inhibition

Regulated functions of hormonal agents play a critical role in health and disease. Target cell responsiveness to a hormonal signal is a product of both cellular concentrations of the hormone ligand and the corresponding receptor protein. The major thrust of the drug design for treatment of endocrine-related problems, so far, has been directed to ligand derivatives. In certain cases, receptor regulation through antigene technology has much to offer with improvements in both target cell and hormonal specificity. Three different antigene approaches are currently being explored. The first approach is to inhibit the expression of the receptor gene by disrupting the DNA protein interaction at critical cis-elements by short triple helix-forming oligonucleotides. The second approach is to sequester and inactivate the receptor mRNA by the antisense mRNA produced in the target tissue directed by a heterologous tissue-specific promoter. The third approach is the tissue-specific expression of a catalytic ribozyme that binds to the specific receptor mRNA and selectively degrades it before its translation into the protein. In this study, we have characterized the promoter of the rat androgen receptor, and by progressive deletion from its 5' end have identified two critical cis-regulatory elements, one at the -960 to -940 region and the other at the -554 to -574 positions. The former is an activator while the latter is an inhibitor domain. The inhibitory domain is the binding site for the nuclear factor kappa B (NF-kappa B) and more specifically, the p50/p50 homodimer of this transcription factor family. We have also provided correlative data to show that under normal physiological conditions, the NF-kappa B functions as an antiandrogen during the age-dependent desensitization of the liver. In addition to the naturally functioning antiandrogenic influence of NF-kappa B, we have designed an artificial antiandrogenic agent, a triplex-forming oligonucleotide (TFO) directed to the -960/-940 activator domain of the rat androgen receptor gene promoter. This oligonucleotide at a TFO-to-promoter ratio of 500 is able to cause about 60% inhibition of rAR promoter function in transfected COS-1 cells. These results clearly demonstrate the feasibility of the antigene approach for effective inhibition of steroid hormone action.

Sonography of the costal cartilage: normal anatomy and preliminary clinical application

Costal cartilages of 10 controls and 12 patients with Tietze's syndrome (n = 6), deformed (exaggerated bowing) cartilage (n = 4), focal enlargement (n = 1), and cancer-invaded cartilage (n = 1) were examined with ultrasonography. In controls, ultrasonography detected 237 of 240 costal cartilages (98.8%) and 58 of 105 intercartilage connections (55%) with three variations. Correlation with CT was available in 7 patients (1 Tietze's syndrome, 4 deformities, 1 cartilage enlargement, and 1 cancer) among 8 patients whose CT results were known to the sonographer. Sonography showed normal (n = 4) or marginally blurred (n = 2) cartilages in 6 Tietze's syndromes. Ultrasonography is a promising technique in the examination of costal cartilages.