Pleiotropic endophenotypic and phenotype effects of GABAergic neurosteroid synthesis deficiency in posttraumatic stress disorder

PTSD is associated with deficits in synthesis of progesterone metabolites such as allopregnanolone and pregnanolone that potently facilitate gamma-amino-butyric acid (GABA) effects at GABA_A receptors. These neurosteroids modulate neuronal firing rate, regional brain connectivity, and activation of amygdala-mediated autonomic nervous system, hypothalamic-pituitary-adrenal axis, and behavioral reactions to unconditioned and conditioned threat. They also play critical roles in learning and memory processes such as extinction and extinction retention and inhibit toll-like receptor activation of intracellular pro-inflammatory pathways. Deficient synthesis of these neurosteroids thus may contribute to individually variable PTSD clinical phenotypes encompassing symptom severity, capacity for PTSD recovery, and vulnerability to common PTSD-comorbidities such as major depression, chronic pain, alcohol and nicotine dependence, cardiovascular disease, metabolic syndrome, reproductive disorders, and autoimmune conditions.

A role for deficits in GABAergic neurosteroids and their metabolites with NMDA receptor antagonist activity in the pathophysiology of posttraumatic stress disorder

Trauma-focused psychotherapies show general efficacy in post-traumatic stress disorder (PTSD), although outcomes vary substantially among individuals with PTSD and many patients do not achieve clinically meaningful symptom improvement. Several factors may contribute to poor treatment response, including genetic or environmental (e.g., stress) effects on neurobiological factors involved in learning and memory processes critical to PTSD recovery. In this review, we discuss the relationship between deficient GABAergic neurosteroid metabolites of progesterone, allopregnanolone (Allo) and pregnanolone (PA), and PTSD symptoms in men and women or PTSD-like behavioral abnormalities observed in male rodent models of PTSD. We also review the role and molecular underpinnings of learning and memory processes relevant to PTSD recovery, including extinction, extinction retention, reconsolidation of reactivated aversive memories and episodic non-aversive memory. We then discuss preclinical and clinical research that supports a role in these learning and memory processes for GABAergic neurosteroids and sulfated metabolites of Allo and PA that allosterically antagonize NMDA receptor function. Studies supporting the possible therapeutic impact of appropriately timed, acutely administered Allo or Allo analogs to facilitate extinction retention and/or block reconsolidation of aversive memories are also reviewed. Finally, we discuss important future directions for research in this area. Examining the varied and composite effects in PTSD of these metabolites of progesterone, as well as neuroactive derivatives of other parent steroids produced in the brain and the periphery, will likely enable a broadening of targets for treatment development. Defining contributions of these neuroactive steroids to common PTSD-comorbid psychiatric and medical conditions, as well as subpopulation-specific underlying dysfunctional physiological processes such as hypothalamic-pituitary-adrenal axis and immune system dysregulation, may also enable development of more effective multisystem precision medicines to prevent and treat the broader, polymorbid sequelae of extreme and chronic stress.

Allergic Diseases and Immune-Mediated Food Disorders in Pediatric Acute-Onset Neuropsychiatric Syndrome

Background: The prevalence and impact of allergic and immune-mediated food disorders in pediatric acute-onset neuropsychiatric syndrome (PANS) are mostly unknown. Objective: We sought to explore the prevalence of atopic dermatitis (AD), asthma, allergic rhinitis (AR), IgE-mediated food allergies (FAs), and other immune-mediated food disorders requiring food avoidance in patients with PANS. In addition, to further understand the extent of food restriction in this population, we investigated the empiric use of dietary measures to improve PANS symptoms. Methods: Pediatric patients in a PANS Clinic and Research Program were given surveys regarding their caregiver burdens, allergic and food-related medical history, and whether food elimination resulted in perception of improvement of PANS symptoms. A review of health records was conducted to confirm that all responses in the survey were concordant with documentation of each patient's medical chart. Results: Sixty-nine (ages 4-20 years) of 80 subjects who fulfilled PANS criteria completed the surveys. Thirteen (18.8%) had AD, 11 (15.9%) asthma, 33 (47.8%) AR, 11 (15.9%) FA, 1 (1.4%) eosinophilic gastrointestinal disorders, 1 (1.4%) food protein-induced enterocolitis syndrome, 3 (4.3%) milk protein-induced proctocolitis syndrome, and 3 (4.3%) celiac disease. Thirty subjects (43.5%) avoided foods due to PANS; elimination of gluten and dairy was most common and was associated with perceived improvement of PANS symptoms (by parents). This perceived improvement was not confirmed with objective data. Conclusions: The prevalence of allergic and immune-mediated food disorders in PANS is similar to the general population as reported in the literature, with the exception of AR that appears to be more prevalent in our PANS cohort. More research will be required to establish whether diet or allergies influence PANS symptoms.

Effect of Early and Prophylactic Nonsteroidal Anti-Inflammatory Drugs on Flare Duration in Pediatric Acute-Onset Neuropsychiatric Syndrome: An Observational Study of Patients Followed by an Academic Community-Based Pediatric Acute-Onset Neuropsychiatric Syndrome Clinic

INTRODUCTION

Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) is characterized by the sudden onset of severe obsessive-compulsive symptoms and/or eating restriction along with at least two coinciding neuropsychiatric symptoms. When associated with group A Streptococcus, the syndrome is labeled Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal infections (PANDAS). An abnormal immune response to infection and subsequent neuroinflammation is postulated to play an etiologic role. We evaluated the impact of nonsteroidal anti-inflammatory drug (NSAID) treatment on flare duration in PANS/PANDAS.

METHODS

Patient inclusion criteria: Patients were included if they had at least one neuropsychiatric deterioration ("flare") that met strict PANS/PANDAS research criteria and for which flare duration could be assessed. Flare inclusion criteria: Any flare that started before October 15, 2016 was included and followed until the flare resolved or until the end of our data collection (November 1, 2016). Flare exclusion criteria: Flares were excluded if they were incompletely resolved, treated with aggressive immunomodulation, or treated with NSAIDs late (>30 days of flare onset). Ninety-five patients met study inclusion criteria and collectively experienced 390 flares that met flare criteria. Data were analyzed using multilevel linear models, adjusting for demographics, disease, and treatment covariates.

RESULTS

NSAID use was associated with a significantly shorter flare duration. Flares not treated with NSAIDs had a mean duration of approximately 12.2 weeks (95% CI: 9.3-15.1). Flares that occurred while the child was on NSAID maintenance therapy were approximately 4 weeks shorter than flares not managed with NSAIDs (95% CI: 1.85-6.24; p < 0.0001). Flares treated with NSAIDs within 30 days of flare onset were approximately 2.6 weeks shorter than flares not managed with NSAIDs (95% CI: 0.43-4.68; p = 0.02). Flares treated prophylactically and those treated early with NSAIDs did not differ in duration (p = 0.26). Among the flares that received NSAID treatment within the first 30 days, earlier intervention was modestly associated with shorter flare durations (i.e., for each day that NSAID treatment was delayed, flare duration increased by 0.18 weeks; 95% CI: 0.03-0.33; p = 0.02), though it was not statistically significant after controlling for covariates (p = 0.06).

CONCLUSION

NSAIDs given prophylactically or within 30 days of flare onset may shorten neuropsychiatric symptom duration in patients with new-onset and relapsing/remitting PANS and PANDAS. A randomized placebo-control clinical trial of NSAIDs in PANS is warranted to formally assess treatment efficacy.

Examination of tetrahydrobiopterin pathway genes in autism

Autism is a complex disorder with a high degree of heritability and significant phenotypic and genotypic heterogeneity. Although candidate gene studies and genome-wide screens have failed to identify major causal loci associated with autism, numerous studies have proposed association with several variations in genes in the dopaminergic and serotonergic pathways. Because tetrahydrobiopterin (BH4) is the essential cofactor in the synthesis of these two neurotransmitters, we genotyped 25 SNPs in nine genes of the BH4 pathway in a total of 403 families. Significant nominal association was detected in the gene for 6-pyruvoyl-tetrahydropterin synthase, PTS (chromosome 11), with P = 0.009; this result was not restricted to an affected male-only subset. Multilocus interaction was detected in the BH4 pathway alone, but not across the serotonin, dopamine and BH4 pathways.

Expression and purification of an anti-Foot-and-mouth disease virus single chain variable antibody fragment in tobacco plants

Low-cost recombinant antibodies could provide a new strategy to control Foot-and-mouth disease virus (FMDV) outbreaks by passive immunization of susceptible animals. In this study, a single chain variable antibody fragment (scFv) recognizing FMDV coat protein VP1 was expressed in transgenic tobacco plants. To enhance the accumulation of scFv protein, the codon-usage of a murine hybridoma-derived scFv gene was adjusted to mimic highly expressed tobacco genes and fused to an elastin-like polypeptide (ELP) tag. This scFv-ELP fusion accumulated up to 0.8% of total soluble leaf protein in transgenic tobacco. To recover scFv-ELP protein from the leaf extract, a simple and scalable purification strategy was established. Purified scFv-ELP fusion was cleaved to separate the scFv portion. Finally, it was shown that the purified scFv proteins retained their capacity to bind the FMDV in the absence or presence of ELP fusion.

The hedgehog pathway regulates remodelling responses to biliary obstruction in rats

BACKGROUND

Chronic biliary obstruction provokes fibrosis and accumulation of immature ductular cells. This fibroductular reaction resolves following biliary decompression, suggesting that it may also be involved in the repair of biliary damage. The hedgehog (Hh) pathway becomes activated in liver after bile duct ligation (BDL), and might modulate hepatic remodelling because Hh ligands are potent morphogens.

OBJECTIVE

To study the induction of the Hh pathway during progression and resolution of biliary fibrosis, and to clarify whether Hh signalling regulates accumulation of bile duct progenitor cells.

DESIGN AND MAIN OUTCOME MEASURES

Livers from rats with BDL were examined by quantitative real-time polymerase chain reaction analysis and immunohistochemistry to identify factors that might stimulate Hh signalling. BDL rats were subjected to Roux-en-Y hepaticojejunostomy (R-Y) to relieve biliary obstruction in order to determine whether these factors and Hh signalling declined as ductular populations and concomitant fibrosis regressed. Cultures of immature ductular cells were treated with putative Hh inducers and Hh ligands to confirm their functional relevance.

RESULTS

BDL increased expression of platelet-derived growth factor-BB (PDGF-BB) and sonic hedgehog (Shh), downregulated hedgehog-interacting protein (Hip), activated Hh signalling, and expanded populations of Hh-responsive ductular cells that expressed pancyotkeratin, a liver progenitor cell marker. After R-Y, Hip remained suppressed, expression of PDGF-BB and Shh gradually declined, and populations of hedgehog-responsive ductular cells regressed. In cultured ductular cells, PDGF-BB treatment induced Shh expression, and incubation with Shh inhibited apoptotic activity.

CONCLUSIONS

These results identify a mechanism for activation of the Hh pathway during cholestasis and suggest that Hh signalling regulates ductular cell accumulation after biliary injury.

Programmes, resources, and needs of HIV-prevention nongovernmental organizations (NGOs) in Africa, Central/Eastern Europe and Central Asia, Latin America and the Caribbean

This study assessed the programmes, resources, and needs of HIV-prevention nongovernmental organizations (NGOs) in 75 countries in Africa, Central/Eastern Europe and Central Asia, Latin America and the Caribbean. Multiple databases and expert recommendations were used to identify one major HIV-prevention NGO in the capital or a large city in each country, and in-depth interviews were conducted with each NGO Director. Most NGOs are carrying out their programmes with minimal funding and few regularly employed personnel. Most are highly dependent on international donors, but reliance on small grants with short funding periods limits programme development capacity. HIV-prevention activities varied by region, with African NGOs most likely to use peer education and community awareness events; Eastern European NGOs most likely to offer needle exchange; Latin American NGOs to have resource centres and offer risk reduction programmes; and Caribbean organizations to use mass education approaches. Across regions, NGOs most often targeted the general public and youth, although specialized at-risk groups were the additional focus of attention in some regions. Limited funding, governmental indifference or opposition, AIDS stigma, and social discomfort discussing sex were often cited as barriers to new HIV-prevention programmes. NGOs are critical service providers. However, their funding, programmes, and resource capacities must be strengthened if NGOs are to realize their full potential in HIV prevention.

HIV prevention nongovernmental organizations in Central and Eastern Europe: programs, resources and challenges

HIV incidence is rising more rapidly in some areas of Central and Eastern Europe than anywhere else in the world. Carrying out effective HIV prevention programs requires the presence of "bridges" that can reach community populations most vulnerable to the disease. Nongovernmental organizations (NGOs) are in a natural role to conduct HIV prevention programs. The Directors of 29 HIV prevention NGOs representing almost all countries in Central and Eastern Europe participated in in-depth interviews by telephone. The broad topics of these interviews included descriptions of the three largest programs conducted by each NGO during the past six months, at-risk target populations served, major barriers faced, and funding sources that sponsored HIV prevention activities. NGO programs most often targeted injection drug users (IDUs); other stigmatized groups were less frequently served by NGOs in the sample. The most common types of prevention activities were needle exchange, HIV prevention peer education, and delivering AIDS presentations and distributing educational materials. Among the major barriers that hampered effective conduct of HIV prevention programs were a shortage of available financial resources, governmental indifference or opposition, and AIDS-related stigma. National governments rarely provided substantial funds for NGO programs, and most funding came from United Nations agencies or private foundations. The information sources reported to be most helpful in assisting NGOs in program development were sharing ideas with other NGOs, participating in conferences, and accessing information from the Internet. A number of programs reported by the NGO Directors were innovative, outstanding, and comprehensive. Five such exemplary programs are described in this article. HIV epidemics in the region are still potentially controllable. NGOs need immediate support so that they can carry out their community-based activities on a larger scale.

Constitutive nuclear factor kappaB activity is required for survival of activated B cell-like diffuse large B cell lymphoma cells

Gene expression profiling has revealed that diffuse large B cell lymphoma (DLBCL) consists of at least two distinct diseases. Patients with one DLBCL subtype, termed activated B cell-like (ABC) DLBCL, have a distinctly inferior prognosis. An untapped potential of gene expression profiling is its ability to identify pathogenic signaling pathways in cancer that are amenable to therapeutic attack. The gene expression profiles of ABC DLBCLs were notable for the high expression of target genes of the nuclear factor (NF)-kappaB transcription factors, raising the possibility that constitutive activity of the NF-kappaB pathway may contribute to the poor prognosis of these patients. Two cell line models of ABC DLBCL had high nuclear NF-kappaB DNA binding activity, constitutive IkappaB kinase (IKK) activity, and rapid IkappaB(alpha) degradation that was not seen in cell lines representing the other DLBCL subtype, germinal center B-like (GCB) DLBCL. Retroviral transduction of a super-repressor form of IkappaBalpha or dominant negative forms of IKKbeta was toxic to ABC DLBCL cells but not GCB DLBCL cells. DNA content analysis showed that NF-kappaB inhibition caused both cell death and G1-phase growth arrest. These findings establish the NF-kappaB pathway as a new molecular target for drug development in the most clinically intractable subtype of DLBCL and demonstrate that the two DLBCL subtypes defined by gene expression profiling utilize distinct pathogenetic mechanisms.

Evidence for alternate splicing within the mRNA transcript encoding the DNA damage response kinase ATR

Proper cellular response to genotoxic insult often requires the activity of one or more members of a family of high-molecular weight protein kinases referred to as phosphatidylinositol-3 kinase (PIK)-like proteins. While catalytic activity is an indispensable part of PIK-like protein function, little is currently known about factors that control their activity and/or functions. This deficiency stems, in large part, from our lack of knowledge concerning functionally significant subdomains within the large non-catalytic domain of these proteins. We have determined that the transcript encoding the PIK-like protein ATR undergoes alternate splicing within the region of the mRNA encoding its non-catalytic domain. This conclusion is based on the sequencing of a human expressed sequence tag clone encoding a portion of the ATR cDNA, and is supported by the results of reverse transcriptase-polymerase chain reaction (RT-PCR) assays conducted on total and polyA+ RNA, as well as sequencing of cloned RT-PCR products. Cloning and sequencing of a segment of human genomic DNA indicated that this event arises from splicing of a single 192 bp exon within the ATR gene. Analysis of several human tissues indicated that alternate ATR transcripts are differentially expressed, suggesting that this region of the ATR protein may be of functional importance.

Ataxia telangiectasia mutated is essential during adult neurogenesis

Ataxia telangiectasia (A-T) is an autosomal recessive disease characterized by normal brain development followed by progressive neurodegeneration. The gene mutated in A-T (ATM) is a serine protein kinase implicated in cell cycle regulation and DNA repair. The role of ATM in the brain and the consequences of its loss on neuronal survival remain unclear. We studied the role of ATM in adult neural progenitor cells in vivo and in vitro to define the role of ATM in dividing and postmitotic neural cells from Atm-deficient (Atm(-/-)) mice in a physiologic context. We demonstrate that ATM is an abundant protein in dividing neural progenitor cells but is markedly down-regulated as cells differentiate. In the absence of ATM, neural progenitor cells of the dentate gyrus show abnormally high rates of proliferation and genomic instability. Atm(-/-) cells in vivo, and in cell culture, show a blunted response to environmental stimuli that promote neural progenitor cell proliferation, survival, and differentiation along a neuronal lineage. This study defines a role for ATM during the process of neurogenesis, demonstrates that ATM is required for normal cell fate determination and neuronal survival both in vitro and in vivo, and points to a mechanism for neuronal cell loss in progressive neurodegenerative diseases.

Heparin-binding epidermal-growth-factor-like growth factor gene expression is induced by scrape-wounding epithelial cell monolayers: involvement of mitogen-activated protein kinase cascades

Peptide growth factors can promote the cell migration and proliferation that is needed to repair epithelia after mechanical or chemical injury. We report here that scrape-wounding rat intestinal epithelial (RIE-1) cell monolayers caused a rapid increase in levels of heparin-binding epidermal-growth-factor-like growth factor (HB-EGF) mRNA, with a maximal response at approx. 1 h. Hybridization in situ showed that transcript induction occurred primarily in cells at or near wound borders. The increase in HB-EGF mRNA was preceded by activation of the p42 mitogen-activated protein kinase (MAPK) in the wounded cell cultures. Moreover, the induction of HB-EGF mRNA was blocked by PD098059 and U0126, inhibitors that prevent the activation of p42/p44 MAPKs and extracellular signal-regulated protein kinase 5 (ERK5). Both p42 MAPK activation and HB-EGF mRNA induction were inhibited by genistein, indicating a requirement for an upstream tyrosine kinase activity. In contrast, neither response was affected by inhibition of phosphoinositide 3-kinase activity, down-regulation of protein kinase C, or disruption of the actin cytoskeleton with cytochalasin B. We conclude that scrape-wounding epithelial cell monolayers induces HB-EGF mRNA expression by a mechanism that most probably requires p42/p44 MAPK activation, although we cannot exclude a role for ERK5. Our results suggest a physiological role for locally synthesized HB-EGF in promoting epithelial repair after injury.

Cyclic AMP inhibits agonist-induced heparin-binding EGF gene expression independently of effects on p42/p44 MAPK activation

Heparin-binding EGF-like growth factor (HB-EGF) mRNA levels are increased up to 20-fold in RIE-1 cells by two agonists that act through distinct receptor types. We demonstrated a common requirement for p42/p44 mitogen-activated protein kinase (MAPK) in this response using the selective MAPK kinase (MEK) inhibitor, PD 098059. Agonist-mediated induction of HB-EGF mRNA was markedly suppressed in cells that had been treated with cyclic AMP-elevating agents. In contrast, the activation of p42 MAPK in response to agonists was not affected by raising cellular cyclic AMP levels. We conclude that cyclic AMP negatively regulates the HB-EGF gene, but that the inhibitory action is either independent of the p42/p44 MAPK pathway or the site of action is distal to MAPK activation.

Regulation of DNA-dependent protein kinase activity by ionizing radiation-activated abl kinase is an ATM-dependent process

Ionizing radiation (IR) treatment results in activation of the nonreceptor tyrosine kinase c-Abl because of phosphorylation by ATM. In vitro evidence indicates that DNA-dependent protein kinase (DNA-PK) can also phosphorylate and thus potentially activate Abl kinase activity in response to IR exposure. To unravel the role of ATM and DNA-PK in the activation of Abl, we assayed Abl, ATM, and DNA-PK activity in ATM- and DNA-PKcs-deficient cells after irradiation. Our results show that despite the presence of higher than normal levels of DNA-PK kinase activity, c-Abl fails to become activated after IR exposure in ATM-deficient cells. Conversely, normal activation of both ATM and c-Abl occurs in DNA-PKcs-deficient cells, indicating that ATM but not DNA-PK is required for activation of Abl in response to IR treatment. Moreover, activation of Abl kinase activity by IR correlates well with activation of ATM activity in all phases of the cell cycle. These results indicate that ATM is primarily responsible for activation of Abl in response to IR exposure in a cell cycle-independent fashion. Examination of DNA-PK activity in response to IR treatment in Abl-deficient cells expressing mutant forms of Abl or in normal cells exposed to an inhibitor of Abl suggests an in vivo role for Abl in the down-regulation of DNA-PK activity. Collectively, these results suggest a convergence of the ATM and DNA-PK pathways in the cellular response to IR through c-Abl kinase.

Characterisation of the rat heparin-binding epidermal growth factor-like growth factor gene promoter

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) gene expression is strongly activated by a variety of extracellular stimuli, acting through the Raf/MEK/MAP kinase pathway. To study the elements that respond to this pathway, we have isolated and sequenced a fragment of the rat HB-EGF gene promoter. By transfection of a series of promoter/reporter constructs into cells, a minimal promoter element was demonstrated to lie between 448 bp upstream of the transcriptional start site and 103 bp into the first exon of the gene. However co-transfection of the promoter constructs with a plasmid directing expression of RafCAAX, an activated c-Raf-1 protein, gave a fold-stimulation of activity no greater than that seen for the parental pGL3-Basic plasmid alone. In addition, agonist stimulation of cell lines stably transfected with a HB-EGF promoter/luciferase construct produced little or no increase in reporter enzyme activity. These results suggest that the c-Raf-1 responsive elements lie outside the tested region of the rat HB-EGF gene. However, it has been reported that a c-Raf-1 responsive element is present within the equivalent region of the mouse gene. A comparison of the 5'-flanking regions of the mouse, rat and human HB-EGF genes indicated that the mouse sequence diverges abruptly from that of the other two species approximately 260 bp upstream of the transcriptional start site. PCR analysis of mouse genomic DNA suggests that this sequence divergence is due to DNA rearrangement during the cloning of the mouse gene. Additional studies are therefore required to identify Raf/MAP kinase responsive elements in the HB-EGF gene.

Solid-phase parallel synthesis of azarene pyrrolidinones as factor Xa inhibitors

A focused library (4 x 14) prepared from 4-aminopyridine and 4-, 5-, and 6-azoindole templates was synthesized using 14 polymer supported 4-amido-2,3,5,6-tetrafluorophenyl (TFP) sulfonate esters inputs. Several compounds were identified as factor Xa inhibitors (IC50< or =0.1 microM) helping to establish the SAR among these four series of azarene pyrrolidinones.

Ionizing radiation exposure results in up-regulation of Ku70 via a p53/ataxia-telangiectasia-mutated protein-dependent mechanism

Genome damaging events, such as gamma-irradiation exposure, result in the induction of pathways that activate DNA repair mechanisms, halt cell cycle progression, and/or trigger apoptosis. We have investigated the effects of gamma-irradiation on cellular levels of the Ku autoantigens. Ku70 and Ku80 have been shown to form a heterodimeric complex that can bind tightly to free DNA ends and activate the protein kinase DNA-PKcs. We have found that irradiation results in an up-regulation of cellular levels of Ku70, but not Ku80, and that this enhanced level of Ku70 accumulates within the nucleus. Further, we uncovered that the postirradiation up-regulation of Ku70 utilizes a mechanism that is dependent on both p53 and damage response protein kinase ATM (ataxia-telangiectasia-mutated); however, the activation of DNA-PK does not require Ku70 up-regulation. These findings suggest that Ku70 up-regulation provides the cell with a means of assuring either proper DNA repair or an appropriate response to DNA damage independent of DNA-PKcs activation.

Amido-(propyl and allyl)-hydroxybenzamidines: development of achiral inhibitors of factor Xa

The design, synthesis and SAR of amido-(propyl and allyl)-hydroxybenzamidine coagulation factor Xa inhibitors is described. These achiral inhibitors are selective for fXa vis a vis structurally related serine proteases and are readily prepared in 6-7 linear steps. The most potent member 9j (fXa Ki = 0.75 nM) is selective (>1000-fold) and an effective anticoagulant in mammalian plasma.

ATM is a cytoplasmic protein in mouse brain required to prevent lysosomal accumulation

We previously generated a mouse model with a mutation in the murine Atm gene that recapitulates many aspects of the childhood neurodegenerative disease ataxia-telangiectasia. Atm-deficient (Atm-/-) mice show neurological defects detected by motor function tests including the rota-rod, open-field tests and hind-paw footprint analysis. However, no gross histological abnormalities have been observed consistently in the cerebellum of any line of Atm-/- mice analyzed in most laboratories. Therefore, it may be that the neurologic dysfunction found in these animals is associated with predegenerative lesions. We performed a detailed analysis of the cerebellar morphology in two independently generated lines of Atm-/- mice to determine whether there was evidence of neuronal abnormality. We found a significant increase in the number of lysosomes in Atm-/- mice in the absence of any detectable signs of neuronal degeneration or other ultrastructural anomalies. In addition, we found that the ATM protein is predominantly cytoplasmic in Purkinje cells and other neurons, in contrast to the nuclear localization of ATM protein observed in cultured cells. The cytoplasmic localization of ATM in Purkinje cells is similar to that found in human cerebellum. These findings suggest that ATM may be important as a cytoplasmic protein in neurons and that its absence leads to abnormalities of cytoplasmic organelles reflected as an increase in lysosomal numbers.

Quantitative analysis reveals differential expression of mucin (MUC2) and intestinal trefoil factor mRNAs along the longitudinal axis of rat intestine

MUC2 and intestinal trefoil factor (ITF) are considered to have important roles in intestinal mucosal protection and epithelial repair. In order to investigate whether these genes are co-ordinately expressed, we have used competitive reverse transcription-polymerase chain reaction assays to measure MUC2 and ITF mRNA levels in human intestinal cell lines and along the longitudinal axis of rat intestine. ITF mRNA was expressed in several intestinal cell lines. However, MUC2 mRNA was detected only in LS174T cells where it was present at approx. 25-fold lower levels than the ITF transcript. In contrast, in rat intestinal tissues, MUC2 mRNA levels were generally higher than ITF mRNA levels. The levels of both transcripts increased markedly during postnatal development. In adult rats, the expression patterns of MUC2 and ITF mRNAs along the longitudinal axis of the small intestine were similar, with lowest levels in the proximal duodenum and relatively constant levels in the other regions assayed. In contrast, the expression patterns of MUC2 and ITF in different regions of the large intestine showed a marked divergence. Our results strongly suggest that expression of the MUC2 and ITF genes is not coordinately regulated in intestinal cells.

Synthesis, SAR and in vivo activity of novel thienopyridine sulfonamide pyrrolidinones as factor Xa inhibitors

Thienopyridine sulfonamide pyrrolidinones were found to be potent and selective inhibitors of the coagulation cascade enzyme factor Xa. SAR studies led to several compounds that were selected for further in vivo investigation. These novel aryl binding pocket moieties represent a structural modification to a series of fXa inhibitors. Several compounds proved to be efficacious i.v. antithrombotic agents.

Sulfonamidopyrrolidinone factor Xa inhibitors: potency and selectivity enhancements via P-1 and P-4 optimization

Sulfonamidopyrrolidinones were previously disclosed as a selective class of factor Xa (fXa) inhibitors, culminating in the identification of RPR120844 as a potent member with efficacy in vivo. Recognizing the usefulness of the central pyrrolidinone template for the presentation of ligands to the S-1 and S-4 subsites of fXa, studies to optimize the P-1 and P-4 groups were initiated. Sulfonamidopyrrolidinones containing 4-hydroxy- and 4-aminobenzamidines were discovered to be effective inhibitors of fXa. X-ray crystallographic experiments in trypsin and molecular modeling studies suggest that our inhibitors bind by insertion of the 4-hydroxybenzamidine moiety into the S-1 subsite of the fXa active site. Of the P-4 groups examined, the pyridylthienyl sulfonamides were found to confer excellent potency and selectivity especially in combination with 4-hydroxybenzamidine. Compound 20b (RPR130737) was shown to be a potent fXa inhibitor (K(i) = 2 nM) with selectivity against structurally related serine proteinases (>1000 times). Preliminary biological evaluation demonstrates the effectiveness of this inhibitor in common assays of thrombosis in vitro (e.g. activated partial thromboplastin time) and in vivo (e.g. rat FeCl(2)-induced carotid artery thrombosis model).

Isolation, genomic organization, and expression analysis of Men1, the murine homolog of the MEN1 gene

The mouse homolog of the human MEN1 gene, which is defective in a dominant familial cancer syndrome, multiple endocrine neoplasia type 1 (MEN1), has been identified and characterized. The mouse Men1 transcript contains an open reading frame encoding a protein of 611 amino acids which has 97% identity and 98% similarity to human menin. Sequence of the entire Men1 gene (9.3 kb) was assembled, revealing 10 exons, with exon 1 being non-coding; a polymorphic tetranucleotide repeat was located in the 5'- flanking region. The exon-intron organization and the size of the coding exons 2-9 were well conserved between the human and mouse genes. Fluorescence in situ hybridization localized the Men1 gene to mouse Chromosome (Chr) 19, a region known to be syntenic to human Chr 11q13, the locus for the MEN1 gene. Northern analysis indicated two messages-2.7 kb and 3.1 kb-expressed in all stages of the embryo analyzed and in all eight adult tissues tested. The larger transcript differs from the smaller by the inclusion of an unspliced intron 1. Whole-mount in situ hybridization of 10.5-day and 11.5-day embryos showed ubiquitous expression of Men1 RNA. Western analysis with antibodies raised against a conserved C-terminal peptide identified an approximately 67-kDa protein in the lysates of adult mouse brain, kidney, liver, pancreas, and spleen tissues, consistent with the size of human menin. The levels of mouse menin do not appear to fluctuate during the cell cycle.

Characterization of a mammalian cDNA encoding a protein with high sequence similarity to the Drosophila regulatory protein Rhomboid

The Drosophila regulatory protein Rhomboid has been demonstrated genetically to facilitate signalling within the Spitz/epidermal growth factor receptor/mitogen-activated protein kinase pathway. Using a polymerase chain reaction (PCR)-based strategy, we have cloned a human cDNA which encodes a protein that has high sequence similarity to Rhomboid. The encoded protein, termed rhomboid-related protein (RRP), is predicted to contain seven transmembrane domains. Northern analysis indicates that RRP mRNA is expressed at highest levels in brain and kidney.

Requirement for NF-kappaB in osteoclast and B-cell development

NF-kappaB is a family of related, dimeric transcription factors that are readily activated in cells by signals associated with stress or pathogens. These factors are critical to host defense, as demonstrated previously with mice deficient in individual subunits of NF-kappaB. We have generated mice deficient in both the p50 and p52 subunits of NF-kappaB to reveal critical functions that may be shared by these two highly homologous proteins. We now demonstrate that unlike the respective single knockout mice, the p50/p52 double knockout mice fail to generate mature osteoclasts and B cells, apparently because of defects that track with these lineages in adoptive transfer experiments. Furthermore, these mice present markedly impaired thymic and splenic architectures and impaired macrophage functions. The blocks in osteoclast and B-cell maturation were unexpected. Lack of mature osteoclasts caused severe osteopetrosis, a family of diseases characterized by impaired osteoclastic bone resorption. These findings now establish critical roles for NF-kappaB in development and expand its repertoire of roles in the physiology of differentiated hematopoietic cells.

Atm selectively regulates distinct p53-dependent cell-cycle checkpoint and apoptotic pathways

Atm is part of a pathway that responds to DNA damage from ionizing radiation (IR). This pathway involves p53, as Atm-deficient cell lines and mice are defective in p53 induction after IR. p53 is a multi-functional protein that simultaneously regulates distinct downstream pathways controlling cell-cycle progression and apoptosis. However, the mechanisms by which p53 differentially activates downstream pathways are unknown. To determine the relationship between Atm and p53, we examined cell-cycle and apoptotic responses in Atm-, p53-(ref. 8) and p21-deficient mice after IR in the whole animal. As expected, p53 protein levels were not induced by IR in thymus of Atm-deficient mice. IR-induced cell-cycle checkpoint function was also defective, and induction of p21 was attenuated in thymus from Atm-deficient mice. However, IR-induced apoptosis and Bax induction were completely normal; both of which are mediated by p53. IR-induced thymic apoptosis was suppressed in Atm/p53 double-mutant mice but not in Atm/p21 double mutants, demonstrating p53 dependence and Atm independence. Thus, Atm deficiency results in lack of p53 induction by IR, but only selective disruption of p53-dependent functions. Our results support a model in which upstream effectors such as Atm selectively activate p53 to regulate specific downstream pathways, providing a mechanism for controlling distinct cell-cycle and apoptotic responses.

CENP-E is an essential kinetochore motor in maturing oocytes and is masked during mos-dependent, cell cycle arrest at metaphase II

CENP-E, a kinesin-like protein that is known to associate with kinetochores during all phases of mitotic chromosome movement, is shown here to be a component of meiotic kinetochores as well. CENP-E is detected at kinetochores during metaphase I in both mice and frogs, and, as in mitosis, is relocalized to the midbody during telophase. CENP-E function is essential for meiosis I because injection of an antibody to CENP-E into mouse oocytes in prophase completely prevented progression of those oocytes past metaphase I. Beyond this, CENP-E is modified or masked during the natural, Mos-dependent, cell cycle arrest that occurs at metaphase II, although it is readily detectable at the kinetochores in metaphase II oocytes derived from mos-deficient (MOS-/-) mice that fail to arrest at metaphase II. This must reflect a masking of some CENP-E epitopes, not the absence of CENP-E, in meiosis II because a different polyclonal antibody raised to the tail of CENP-E detects CENP-E at kinetochores of metaphase II-arrested eggs and because CENP-E reappears in telophase of mouse oocytes activated in the absence of protein synthesis.

Identification of a minimal promoter element of the mouse epidermal growth factor gene

We have previously generated a transgenic mouse line (EGF/Tag) in which simian virus 40 (SV40) T-antigen expression is directed by the mouse epidermal growth factor (EGF) gene promoter. In these mice, cellular hyperproliferation is observed in the submaxillary gland associated with SV40 T-antigen expression. In addition, SV40 T-antigen-expressing tumours of prostatic origin are seen. We have now derived immortalized cell lines from these tissues and have used the cells to perform a functional analysis of the EGF gene promoter. Cells were transfected with EGF promoter/reporter constructs, and an element located between 51 and 35 bases upstream of the EGF mRNA start site required for basal activity of the promoter was identified. Electrophoretic mobility-shift analysis suggests that three proteins bind to this region, one of which is either Sp1 or a closely related protein.

Borrelia burgdorferi activates nuclear factor-kappa B and is a potent inducer of chemokine and adhesion molecule gene expression in endothelial cells and fibroblasts

Lyme disease, caused by the tick-borne spirochete Borrelia burgdorferi, is a systemic infection with preponderance for the skin, joints, heart, and nervous system. Inflammatory lesions of target organs are characterized by the presence of spirochetes and inflammatory leukocytes. We have analyzed the potential of B. burgdorferi to induce gene expression of chemokines and adhesion molecules in human endothelial cells, keratinocytes, and fibroblasts. We find induction of the chemokines RANTES (regulated upon activation, normal T cells expressed and secreted), monocyte chemoattractant protein-1, IL-8, gro-alpha, IFN-inducible protein-10, and mig (monokine induced by gamma-IFN), and of the adhesion molecules E-selectin, ICAM-1, and VCAM-1 in endothelial cells and induction of the same chemokines and ICAM-1 in fibroblasts. This is mediated by the lipid moiety of the outer surface lipoprotein A. Induction of chemokine and adhesion molecule genes by B. burgdorferi occurs rapidly and does not require new protein synthesis. Induction is blocked by inhibitors of nuclear factor (NF)-kappa B. We also find that B. burgdorferi induces nuclear translocation of NF-kappa B and a transient increase in the expression of its inhibitor I kappa B-alpha. These findings indicate that B. burgdorferi is a potent inducer of molecules required for leukocyte recruitment to inflammatory foci, and the data suggest that this biologic activity is due to the ability of the spirochetes to activate the pleiotropic transcription factor NF-kappa B.

Borrelia burgdorferi activates nuclear factor-kappa B and is a potent inducer of chemokine and adhesion molecule gene expression in endothelial cells and fibroblasts

Lyme disease, caused by the tick-borne spirochete Borrelia burgdorferi, is a systemic infection with preponderance for the skin, joints, heart, and nervous system. Inflammatory lesions of target organs are characterized by the presence of spirochetes and inflammatory leukocytes. We have analyzed the potential of B. burgdorferi to induce gene expression of chemokines and adhesion molecules in human endothelial cells, keratinocytes, and fibroblasts. We find induction of the chemokines RANTES (regulated upon activation, normal T cells expressed and secreted), monocyte chemoattractant protein-1, IL-8, gro-alpha, IFN-inducible protein-10, and mig (monokine induced by gamma-IFN), and of the adhesion molecules E-selectin, ICAM-1, and VCAM-1 in endothelial cells and induction of the same chemokines and ICAM-1 in fibroblasts. This is mediated by the lipid moiety of the outer surface lipoprotein A. Induction of chemokine and adhesion molecule genes by B. burgdorferi occurs rapidly and does not require new protein synthesis. Induction is blocked by inhibitors of nuclear factor (NF)-kappa B. We also find that B. burgdorferi induces nuclear translocation of NF-kappa B and a transient increase in the expression of its inhibitor I kappa B-alpha. These findings indicate that B. burgdorferi is a potent inducer of molecules required for leukocyte recruitment to inflammatory foci, and the data suggest that this biologic activity is due to the ability of the spirochetes to activate the pleiotropic transcription factor NF-kappa B.

The ataxia-telangiectasia gene product, a constitutively expressed nuclear protein that is not up-regulated following genome damage

The product of the ataxia-telangiectasia gene (ATM) was identified by using an antiserum developed to a peptide corresponding to the deduced amino acid sequence. The ATM protein is a single, high-molecular weight protein predominantly confined to the nucleus of human fibroblasts, but is present in both nuclear and microsomal fractions from human lymphoblast cells and peripheral blood lymphocytes. ATM protein levels and localization remain constant throughout all stages of the cell cycle. Truncated ATM protein was not detected in lymphoblasts from ataxia-telangiectasia patients homozygous for mutations leading to premature protein termination. Exposure of normal human cells to gamma-irradiation and the radiomimetic drug neocarzinostatin had no effect on ATM protein levels, in contrast to a noted rise in p53 levels over the same time interval. These findings are consistent with a role for the ATM protein in ensuring the fidelity of DNA repair and cell cycle regulation following genome damage.

Molecular perspectives on cancer, the cell cycle and the inherited disorder ataxia-telangiectasia

Ataxia-Telangiectasia (A-T) is an autosomal recessive disorder which presents a wide array of clinical symptoms including enhanced cancer predisposition and progressive cerebellar degeneration leading to general neuromotor dysfunction. The A-T cellular phenotype consists of higher levels of chromosome breakage, increased sensitivity to ionizing radiation and radiomimetic drugs, and defective cell cycle checkpoints in response to genome damage. Positional-cloning of the gene mutated in A-T, designated ATM, identified a 13 kb transcript encoding a 3056 amino acid protein which possesses a carboxy-terminal domain with distinct homology to phosphatidylinositol-3 kinase. Furthermore, ATM related proteins have been identified in yeast, Drosophila and other mammalian species which are involved in cell cycle control and cellular responses to DNA damage. Development of cellular and animal models for A-T can serve to better dissect the role and involvement of ATM in cell cycle regulation, cancer development, neuronal cell death and other hallmark symptoms of this disorder.

Inositol 1,4,5-trisphosphate-mediated Ca2+ release from platelet internal membranes is regulated by differential phosphorylation

Platelets are activated by an increase in cytosolic Ca2+, and a portion of this increase is derived from inositol 1,4,5-trisphosphate (InsP3)-mediated Ca2+ release from internal stores via the InsP3 receptor. Cytosolic cAMP inhibits platelet activation, and experiments were designed to determine if cAMP-dependent phosphorylation affects the rate of InsP3-mediated Ca2+ release. Western blotting of platelet internal membranes with anti-InsP3 receptor and anti-actin binding protein antibodies revealed that the platelet contains type 1 InsP3 receptor and that it is distinct from actin binding protein. The platelet InsP3 receptor was shown to be phosphorylated by endogenous, membrane-bound kinases as well as by exogenous protein kinase A. Prior phosphorylation of the insP3 receptor by endogenous kinases inhibited additional protein kinase A-dependent phosphorylation by 60%. Furthermore, endogenous phosphorylation resulted in a 2-fold increase in the InsP3-mediated Ca2+ release rate relative to dephosphorylated controls. Following endogenous phosphorylation, additional phosphorylation by protein kinase A returned the Ca2+ release rate to control values, while protein kinase A-dependent phosphorylation of dephosphorylated membranes did not affect the release rate. These results suggest that the InsP3 receptor within intact platelets is phosphorylated by endogenous kinases which results in a high InsP3-mediated Ca2+ release rate, and that increases in cAMP result in additional phosphorylation that inhibits Ca2+ release, thus contributing to inhibition of platelet activation.

The kinesin-like protein CENP-E is kinetochore-associated throughout poleward chromosome segregation during anaphase-A

The kinesin-like protein CENP-E transiently associates with kinetochores following nuclear envelope breakdown in late prophase, remains bound throughout metaphase, but sometime after anaphase onset it releases and by telophase becomes bound to interzonal microtubules of the mitotic spindle. Inhibition of poleward chromosome movement in vitro by CENP-E antibodies and association of CENP-E with minus-end directed microtubule motility in vitro have combined to suggest a key role for CENP-E as an anaphase chromosome motor. For this to be plausible in vivo depends on whether CENP-E remains kinetochore associated during anaphase. Using Indian muntjac cells whose seven chromosomes have large, easily tracked kinetochores, we now show that CENP-E is kinetochore-associated throughout the entirety of anaphase-A (poleward chromosome movement), relocating gradually during spindle elongation (anaphase-B) to the interzonal microtubules. These observations support roles for CENP-E not only in the initial alignment of chromosomes at metaphase and in spindle elongation in anaphase-B, but also in poleward chromosome movement in anaphase-A.

Production of heparin-binding epidermal growth factor-like growth factor (HB-EGF) at sites of thermal injury in pediatric patients

Fluids that accumulate at wound sites may be an important reservoir of growth factors that promote the normal wound healing response. The presence of heparin-binding growth factors was studied in burn wound fluid (BWF) from 45 pediatric patients who had sustained partial thickness burns. One of the growth factors present was similar to platelet-derived growth factor (PDGF) based on its heparin affinity, inhibition of bioactivity by a PDGF antiserum, and detection in a PDGF-AB enzyme-linked immunosorbent assay. A second growth factor was identified as heparin-binding epidermal growth factor-like growth factor (HB-EGF) based on its heparin affinity, competition with 125I-labeled epidermal growth factor (EGF) for EGF receptor binding, and recognition in biological assays and Western blots by two HB-EGF antisera. Amino acid sequence analysis of one form of this second growth factor verified its identity as an N-terminally truncated form of HB-EGF. Immunohistochemical analysis of partial thickness burns demonstrated the presence of HB-EGF in the advancing epithelial margin, islands of regenerating epithelium within the burn wound, and in the duct and proximal tubules of eccrine sweat glands. HB-EGF in the surface epithelium of burn wounds was uniformally distributed, whereas it was restricted to the basal epithelium in nonburned skin. These data support a role for PDGF and HB-EGF in burn wound healing and suggest that the response to injury includes deposition of HB-EGF and PDGF into blister fluid and a redistribution of HB-EGF in the surface epithelium near the wound site.

Chronic systemic treatment with epidermal growth factor in pigs causes pronounced urothelial growth with accumulation of glycoconjugates

Epidermal growth factor (EGF) is present in large amounts in the urine, but the effects of systemically administered EGF on the urinary tract have not been described previously. In the present paper, we describe a potent growth induction of EGF on the urinary tract. Goettingen minipigs were treated with solvent (n = 5), EGF 30 micrograms/kg/day (n = 6) for 4 weeks, or EGF 30 micrograms/kg/day for 5 weeks followed by 3 weeks of recovery (n = 5). The ureters and bladders were examined by routine histology and electron microscopy and were immunostained for proliferating cell nuclear antigen. Four weeks of EGF treatment increased the median cross sectional area of the ureter fourfold with growth of all wall layers. The urothelium was widened from 5 cell layers in the controls to 10 in the EGF-treated animals. Proliferating cell nuclear antigen immunostaining revealed an increased mitotic activity in the basal zone of the urothelium. In the luminal zone, glycoconjugates accumulated in goblet cells, in cells with intracytoplasmic lumina, and beneath the luminal cell membrane in the umbrella cells. Our studies present a new experimental approach to growth induction of the urinary tract. The findings implicate the EGF system in regulating urothelial growth and glycoconjugate biosynthesis.

Identification of a functional promoter element in the 5'-flanking region of the rat cMG1/TIS11b gene

The cMG1 gene was originally identified as a mitogen-stimulated primary response gene. However, in contrast to genes such as c-fos and TIS11, cMG1 is also expressed at significant levels before and after the transient elevation induced by agonists. We have sequenced a 1.3 kb rat genomic cMG1 clone, which includes 931 bp upstream of the transcription start site identified by primer-extension analysis. A 1033 bp fragment, including this 5'-flanking sequence, directed the expression of the reporter gene chloramphenicol acetyltransferase (CAT) in transfected NIH-3T3 cells. Progressive 5'-to-3' deletion indicated that an element located between -138 and -114 was responsible for most of this basal CAT expression. DNA mobility-shift assays showed that the sequence between -143 and -105 contained binding sites for cellular proteins, the principal complexes involving nucleotides between -119 and -105. We conclude that these complexes may represent the transcription factor-DNA element interactions that determine basal cMG1 expression.

The epidermal growth factor/transforming growth factor-alpha family and their receptors

Cytokines and growth factors act as intercellular signalling molecules which control cellular functions during development and in response to injury or infection. The epidermal growth factor (EGF) family is an expanding group of structurally related polypeptides that regulate cell proliferation, migration and differentiation, via tyrosine kinase receptors on target cells. This chapter reviews recent developments in the characterization of EGF family members and their receptors.

Insulin and insulin-like growth factor I stimulate expression of the primary response gene cMG1/TIS11b by a wortmannin-sensitive pathway in RIE-1 cells

The addition of insulin or insulin-like growth factor I (IGF-I) to RIE-1 cells increased the expression of the primary response gene cMG1; dose-response analysis suggested that this effect was mediated largely through type 1 IGF receptors. Insulin/IGF-I did not affect the expression of the cMG1-related genes TIS11 and TIS11d, whereas epidermal growth factor, angiotensin II or 12-O-tetradecanoyl phorbol-13-acetate stimulated the expression of all three genes. Incubation with wortmannin (WM) prevented the insulin/IGF-I-induced elevation of cMG1 mRNA, but not that induced by the other mitogens or the stimulation of mitogen-activated protein kinase by insulin. We conclude that WM-sensitive phosphatidylinositol 3-kinase may be involved in the specific stimulation of cMG1 expression by insulin/IGF-I.

Cerebral ischemia and infarction

Cerebral infarction is most commonly related to atherosclerotic disease in the carotid and vertebrobasilar circulations. TIAs are manifestations of this same disease process and may occur before a complete infarction. The transformation of pale to hemorrhagic infarction may result from reperfusion of an infarct or from migration of an embolus. CT is often the primary imaging study to exclude frank hemorrhage. The use of MR is increasing, in both the acute and the subacute phases of stroke. The combination of MR imaging and MR angiography is gradually replacing CT, particularly in patients with TIAs. In addition, the depiction of minute alterations in contrast and subtle mass effect is visualized with MR more often than with CT. The precise localization of brain stem and posterior fossa infarctions is improved by the ability of MR to view complex structures in two or more orthogonal planes. Vascular structures are readily identified both on the spin echo images and with MR angiography. Slow or obstructed flow in the venous channels may be recognized, which makes MR the ideal examination for the evaluation of cerebral ischemia and infarction.

A family of serine proteases expressed exclusively in myelo-monocytic cells specifically processes the nuclear factor-kappa B subunit p65 in vitro and may impair human immunodeficiency virus replication in these cells

Two groups of U937 promonocytic cells were obtained by limiting dilution cloning which differed strikingly in their ability to support human immunodeficiency virus 1 (HIV-1) replication. "Plus" clones replicated the virus efficiently, whereas "minus" clones did not. We examined these clones for differences in nuclear factor (NF)-kappa B activity which might account for the observed phenomenon. Stimulation of plus clones liberated the classical p50-p65 complex from cytoplasmic pools, whereas minus clones produced an apparently novel, faster-migrating complex, as judged by electrophoretic mobility shift assays. It is surprising that the faster-migrating complex was composed also of p50 and p65. However, the p65 subunit was COOH-terminally truncated, as shown by immunoprecipitation. The truncation resulted from limited proteolysis of p65 during cellular extraction which released particular lysosomal serine proteases, such as elastase, cathepsin G, and proteinase 3. These specific proteases are coordinately expressed and were present exclusively in the minus U937 clones, but not in the plus clones, as demonstrated in the case of cathepsin G. In addition, these proteases were detected in certain subclones of THP-1 and HL-60 cells and in primary monocytes, in each case correlating with the truncated from of p65. We demonstrate in vitro cleavage of p65 by purified elastase and cathepsin G. It is possible that particular serine proteases may have inhibiting effects on the replication of HIV-1 in myelo-monocytic cells. The data also demonstrate that special precautions must be taken when making extracts from myelo-monocytic cells.

Activation of AT1 angiotensin receptors induces DNA synthesis in a rat intestinal epithelial (RIE-1) cell line

Proliferation of the rat intestinal epithelial cell-line, RIE-1, has previously been shown to be stimulated by certain polypeptide growth factors acting via receptors that possess intrinsic tyrosine kinase activity. In this study, we show that the octapeptide hormone angiotensin II (AII), apparently acting through the AT1 G-protein-coupled receptor, is also a mitogen for RIE-1 cells. Maximal stimulation of DNA synthesis and cellular proliferation occurred at an AII concentration of 10-100 nM, with half-maximal stimulation at 1 nM. The mitogenic response to AII was completely inhibited by the AT1 angiotensin-receptor antagonist, DuP753, but not by the AT2-receptor antagonist, PD123319. The early signalling responses activated by AII in RIE-1 cells include increased production of inositol phosphates, a transient increase in the intracellular concentration of free calcium, an activation of protein kinase C, and a rapid change in the pattern of cellular protein-tyrosine phosphorylation. These results implicate an activation of the inositol lipid signalling pathway via the AT1 receptor subtype in the AII-stimulated mitogenic response of this normal epithelial cell line.

Cyclin-like accumulation and loss of the putative kinetochore motor CENP-E results from coupling continuous synthesis with specific degradation at the end of mitosis

CENP-E is a kinesin-like protein that binds to kinetochores through the early stages of mitosis, but after initiation of anaphase, it relocalizes to the overlapping microtubules in the midzone, ultimately concentration in the developing midbody. By immunoblotting of cells separated at various positions in the cell cycle using centrifugal elutriation, we show that CENP-E levels increase progressively across the cycle peaking at approximately 22,000 molecules/cell early in mitosis, followed by an abrupt (> 10 fold) loss at the end of mitosis. Pulse-labeling with [35S]methionine reveals that beyond a twofold increase in synthesis between G1 and G2, interphase accumulation results primarily from stabilization of CENP-E during S and G2. Despite localizing in the midbody during normal cell division, CENP-E loss at the end of mitosis is independent of cytokinesis, since complete blockage of division with cytochalasin has no affect on CENP-E loss at the M/G1 transition. Thus, like mitotic cyclins, CENP-E accumulation peaks before cell division, and it is specifically degraded at the end of mitosis. However, CENP-E degradation kinetically follows proteolysis of cyclin B in anaphase. Combined with cyclin A destruction before the end of metaphase, degradation of as yet unidentified components at the metaphase/anaphase transition, and cyclin B degradation at or after the anaphase transition, CENP-E destruction defines a fourth point in a mitotic cascade of timed proteolysis.

Directed expression of simian virus 40 T-antigen in transgenic mice using the epidermal growth factor gene promoter

A transgenic mouse line (EGF/Tag) has been established in which expression of SV40 T-antigen is directed by a 5.5 kb fragment of the 5'-flanking region of the mouse epidermal growth factor (EGF) gene. Of the two principal sites of EGF expression in mice, submaxillary gland and kidney, T-antigen mRNA and protein were detected in the former but not in the latter tissue of the EGF/Tag animals. T-antigen expression in the submaxillary gland was restricted to the EGF-producing cells of the granular convoluted tubules, and the oncoprotein induced hyperplasia of these cells. T-antigen levels were markedly higher in the submaxillary glands of male compared with female transgenic mice, suggesting that expression of the transgene was androgen-regulated, like the endogenous EGF gene. These results indicate that the 5.5 kb fragment upstream of the mouse EGF gene contains the DNA enhancer elements required for hormonally regulated expression in the submaxillary gland. Since the hyperplastic submaxillary glands of the EGF/Tag mice continue to synthesize EGF, these glands provide a tissue source from which it may prove possible to establish EGF-secreting cell lines for further in vitro studies of the mechanisms regulating expression of the EGF gene.

Cloning and characterization of ERF-1, a human member of the Tis11 family of early-response genes

Members of the Tis11 family of early-response genes are characterized by a high degree of sequence similarity around a putative zinc finger motif. They are induced by a variety of cell agonists and polypeptide mitogens, including 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF). We describe the cloning and sequencing of a human member of this gene family, EGF-response factor 1 (ERF-1), the homolog of the mouse Tis11b/rat cMG1 genes. The human and rodent genes are similar, with 5' UTR, coding sequence, and 3' UTR highly conserved. The promoter/enhancer region and intron sequences contain multiple putative transcription factor binding motifs characteristic of early-response genes. Amino acid sequence comparison of the seven members of the Tis11 family cloned so far identifies a repeated consensus motif of (x+)YKTELC(x+)x5GxCxYGx(x+)CxFxH involving the potential zinc finger. Toward the carboxyterminal end is a region with a high percentage of prolines (15/73) and, partially overlapping, a serine-rich domain (20/54). These may be important as trans-activation and phosphorylation sites. The 3' untranslated region is unusually long, extending over 1,860 bp. The sequence immediately downstream from the translational stop codon has extensive secondary structure potential. The 3' UTR is 60% AT rich, but contains two GC rich (> 70%) regions. In addition there are multiple reiterations of a destabilization sequence, as well as a single UUAUUUAU motif characteristic of mRNAs specifying proteins involved in the inflammatory response. The mRNA contains a consensus polyadenylation signal.

Expression of the genes for the epidermal growth factor receptor and its ligands in porcine oviduct and endometrium

We have used the reverse transcription-polymerase chain reaction (RT-PCR) to determine whether transcripts for the epidermal growth factor (EGF) receptor and its four known ligands--EGF, transforming growth factor alpha (TGF alpha), amphiregulin (Ar), and heparin-binding EGF (HB-EGF)--are expressed in porcine oviduct and endometrium. We were able to detect mRNA for the EGF receptor, EGF, TGF alpha, and Ar in both the oviduct and endometrium, whereas HB-EGF mRNA was not detectable in either tissue. Through use of an antiserum raised against recombinant pig EGF, expression of EGF was found to be localized to the columnar epithelial cells of the oviduct and to the glandular epithelial cells of the endometrium. The possible physiological roles of the EGF family in the reproductive tract are discussed.