Metabolic Regulators Nampt and Sirt6 Serially Participate in the Macrophage Interferon Antiviral Cascade

Molecular determinants underlying interferon (IFN)-macrophage biology can help delineate enzyme systems, pathways and mechanisms for enabling host-directed therapeutic approaches against infection. Notably, while the IFN antiviral response is known to be directly coupled to mevalonate-sterol biosynthesis, mechanistic insight for providing host pathway-therapeutic targets remain incomplete. Here, we show that Nampt and Sirt6 are coordinately regulated upon immune activation of macrophages and contribute to the IFN-sterol antiviral response. In silico analysis of the Nampt and Sirt6 promoter regions identified multiple core immune gene-regulatory transcription factor sites, including Stat1, implicating a molecular link to IFN control. Experimentally, we show using a range of genetically IFN-defective macrophages that the expression of Nampt is stringently regulated by the Jak/Stat-pathway while Sirt6 activation is temporally displaced in a partial IFN-dependent manner. We further show that pharmacological inhibition of Nampt and small interfering RNA (siRNA)-mediated inhibition of Nampt and Sirt6 promotes viral growth of cytomegalovirus in both fibroblasts and macrophages. Our results support the notion of pharmacologically exploiting immune regulated enzyme systems of macrophages for use as an adjuvant-based therapy for augmenting host protective pathway responses to infection.

The cholesterol biosynthesis pathway regulates IL-10 expression in human Th1 cells

The mechanisms controlling CD4+ T cell switching from an effector to an anti-inflammatory (IL-10+) phenotype play an important role in the persistence of chronic inflammatory diseases. Here, we identify the cholesterol biosynthesis pathway as a key regulator of this process. Pathway analysis of cultured cytokine-producing human T cells reveals a significant association between IL-10 and cholesterol metabolism gene expression. Inhibition of the cholesterol biosynthesis pathway with atorvastatin or 25-hydroxycholesterol during switching from IFNγ+ to IL-10+ shows a specific block in immune resolution, defined as a significant decrease in IL-10 expression. Mechanistically, the master transcriptional regulator of IL10 in T cells, c-Maf, is significantly decreased by physiological levels of 25-hydroxycholesterol. Strikingly, progression to rheumatoid arthritis is associated with altered expression of cholesterol biosynthesis genes in synovial biopsies of predisposed individuals. Our data reveal a link between sterol metabolism and the regulation of the anti-inflammatory response in human CD4+ T cells.

Interferon Control of the Sterol Metabolic Network: Bidirectional Molecular Circuitry-Mediating Host Protection

The sterol metabolic network is emerging center stage in inflammation and immunity. Historically, observational clinical studies show that hypocholesterolemia is a common side effect of interferon (IFN) treatment. More recently, comprehensive systems-wide investigations of the macrophage IFN response reveal a direct molecular link between cholesterol metabolism and infection. Upon infection, flux through the sterol metabolic network is acutely moderated by the IFN response at multiple regulatory levels. The precise mechanisms by which IFN regulates the mevalonate-sterol pathway—the spine of the network—are beginning to be unraveled. In this review, we discuss our current understanding of the multifactorial mechanisms by which IFN regulates the sterol pathway. We also consider bidirectional communications resulting in sterol metabolism regulation of immunity. Finally, we deliberate on how this fundamental interaction functions as an integral element of host protective responses to infection and harmful inflammation.

Rapid proteasomal elimination of 3-hydroxy-3-methylglutaryl-CoA reductase by interferon-γ in primary macrophages requires endogenous 25-hydroxycholesterol synthesis

Interferons (IFNs) play a central role in immunity and emerging evidence suggests that IFN-signalling coordinately regulates sterol biosynthesis in macrophages, via Sterol Regulatory Element-Binding Protein (SREBP) dependent and independent pathways. However, the precise mechanisms and kinetic steps by which IFN controls sterol biosynthesis are as yet not fully understood. Here, we elucidate the molecular circuitry governing how IFN controls the first regulated step in the mevalonate-sterol pathway, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), through the synthesis of 25-Hydroxycholesterol (25-HC) from cholesterol by the IFN-inducible Cholesterol-25-Hydroxylase (CH25H). We show for the first 30-min of IFN stimulation of macrophages the rate of de novo synthesis of the Ch25h transcript is markedly increased but by 120-min becomes transcriptionally curtailed, coincident with induction of the Activating Transcription Factor 3 (ATF3) repressor. We demonstrate ATF3 induction by Toll-like receptors is strictly dependent on IFN-signalling. While the SREBP-pathway dependent rates of de novo transcription of Hmgcr are relatively unchanged in the first 90-min of IFN treatment, we find HMGCR enzyme levels undergo a rapid proteasomal-mediated degradation, defining a previously unappreciated SREBP-independent mechanism for IFN-action. These events precede a sustained marked reduction in Hmgcr RNA levels involving SREBP-dependent mechanisms. We demonstrate that HMGCR proteasomal-degradation by IFN strictly requires the synthesis of endogenous 25-HC and functionally couples HMGCR to CH25H to coordinately suppress sterol biosynthesis. In conclusion, we quantitatively delineate proteomic and transcriptional levels of IFN-mediated control of HMGCR, the primary enzymatic step of the mevalonate-sterol biosynthesis pathway, providing a foundational framework for mathematically modelling the therapeutic outcome of immune-metabolic pathways.

The transcription factor STAT-1 couples macrophage synthesis of 25-hydroxycholesterol to the interferon antiviral response

Recent studies suggest that the sterol metabolic network participates in the interferon (IFN) antiviral response. However, the molecular mechanisms linking IFN with the sterol network and the identity of sterol mediators remain unknown. Here we report a cellular antiviral role for macrophage production of 25-hydroxycholesterol (cholest-5-en-3β,25-diol, 25HC) as a component of the sterol metabolic network linked to the IFN response via Stat1. By utilizing quantitative metabolome profiling of all naturally occurring oxysterols upon infection or IFN-stimulation, we reveal 25HC as the only macrophage-synthesized and -secreted oxysterol. We show that 25HC can act at multiple levels as a potent paracrine inhibitor of viral infection for a broad range of viruses. We also demonstrate, using transcriptional regulatory-network analyses, genetic interventions and chromatin immunoprecipitation experiments that Stat1 directly coupled Ch25h regulation to IFN in macrophages. Our studies describe a physiological role for 25HC as a sterol-lipid effector of an innate immune pathway.

A model of flux regulation in the cholesterol biosynthesis pathway: Immune mediated graduated flux reduction versus statin-like led stepped flux reduction

The cholesterol biosynthesis pathway has recently been shown to play an important role in the innate immune response to viral infection with host protection occurring through a coordinate down regulation of the enzymes catalysing each metabolic step. In contrast, statin based drugs, which form the principle pharmaceutical agents for decreasing the activity of this pathway, target a single enzyme. Here, we build an ordinary differential equation model of the cholesterol biosynthesis pathway in order to investigate how the two regulatory strategies impact upon the behaviour of the pathway. We employ a modest set of assumptions: that the pathway operates away from saturation, that each metabolite is involved in multiple cellular interactions and that mRNA levels reflect enzyme concentrations. Using data taken from primary bone marrow derived macrophage cells infected with murine cytomegalovirus or treated with IFNγ, we show that, under these assumptions, coordinate down-regulation of enzyme activity imparts a graduated reduction in flux along the pathway. In contrast, modelling a statin-like treatment that achieves the same degree of down-regulation in cholesterol production, we show that this delivers a step change in flux along the pathway. The graduated reduction mediated by physiological coordinate regulation of multiple enzymes supports a mechanism that allows a greater level of specificity, altering cholesterol levels with less impact upon interactions branching from the pathway, than pharmacological step reductions. We argue that coordinate regulation is likely to show a long-term evolutionary advantage over single enzyme regulation. Finally, the results from our models have implications for future pharmaceutical therapies intended to target cholesterol production with greater specificity and fewer off target effects, suggesting that this can be achieved by mimicking the coordinated down-regulation observed in immunological responses.

Extending signaling pathways with protein-interaction networks. Application to apoptosis

Cells exploit signaling pathways during responses to environmental changes, and these processes are often modulated during disease. Particularly, relevant human pathologies such as cancer or viral infections require downregulating apoptosis signaling pathways to progress. As a result, the identification of proteins responsible for these changes is essential for the diagnostics and development of therapeutics. Transferring functional annotation within protein interaction networks has proven useful to identify such proteins, although this is not a trivial task. Here, we used different scoring methods to transfer annotation from 53 well-studied members of the human apoptosis pathways (as known by 2005) to their protein interactors. All scoring methods produced significant predictions (compared to a random negative model), but its number was too large to be useful. Thus, we made a final prediction using specific combinations of scoring methods and compared it to the proteins related to apoptosis signaling pathways during the last 5 years. We propose 273 candidate proteins that may be relevant in apoptosis signaling pathways. Although some of them have known functions consistent with their proposed apoptotsis involvement, the majority have not been annotated yet, leaving room for further experimental studies. We provide our predictions at http://sbi.imim.es/web/Apoptosis.php.

Reversible inhibition of murine cytomegalovirus replication by gamma interferon (IFN-γ) in primary macrophages involves a primed type I IFN-signaling subnetwork for full establishment of an immediate-early antiviral state

Activated macrophages play a central role in controlling inflammatory responses to infection and are tightly regulated to rapidly mount responses to infectious challenge. Type I interferon (alpha/beta interferon [IFN-α/β]) and type II interferon (IFN-γ) play a crucial role in activating macrophages and subsequently restricting viral infections. Both types of IFNs signal through related but distinct signaling pathways, inducing a vast number of interferon-stimulated genes that are overlapping but distinguishable. The exact mechanism by which IFNs, particularly IFN-γ, inhibit DNA viruses such as cytomegalovirus (CMV) is still not fully understood. Here, we investigate the antiviral state developed in macrophages upon reversible inhibition of murine CMV by IFN-γ. On the basis of molecular profiling of the reversible inhibition, we identify a significant contribution of a restricted type I IFN subnetwork linked with IFN-γ activation. Genetic knockout of the type I-signaling pathway, in the context of IFN-γ stimulation, revealed an essential requirement for a primed type I-signaling process in developing a full refractory state in macrophages. A minimal transient induction of IFN-β upon macrophage activation with IFN-γ is also detectable. In dose and kinetic viral replication inhibition experiments with IFN-γ, the establishment of an antiviral effect is demonstrated to occur within the first hours of infection. We show that the inhibitory mechanisms at these very early times involve a blockade of the viral major immediate-early promoter activity. Altogether our results show that a primed type I IFN subnetwork contributes to an immediate-early antiviral state induced by type II IFN activation of macrophages, with a potential further amplification loop contributed by transient induction of IFN-β.

Host defense against viral infection involves interferon mediated down-regulation of sterol biosynthesis

Upon infection, our immune cells produce a small protein called interferon, which in turn signals a protective response through a series of biochemical reactions that involves lowering the cells' ability to make cholesterol by targeting a gene essential for controlling the pathway for cholesterol metabolism.

Little is known about the protective role of inflammatory processes in modulating lipid metabolism in infection. Here we report an intimate link between the innate immune response to infection and regulation of the sterol metabolic network characterized by down-regulation of sterol biosynthesis by an interferon regulatory loop mechanism. In time-series experiments profiling genome-wide lipid-associated gene expression of macrophages, we show a selective and coordinated negative regulation of the complete sterol pathway upon viral infection or cytokine treatment with IFNγ or β but not TNF, IL1β, or IL6. Quantitative analysis at the protein level of selected sterol metabolic enzymes upon infection shows a similar level of suppression. Experimental testing of sterol metabolite levels using lipidomic-based measurements shows a reduction in metabolic output. On the basis of pharmacologic and RNAi inhibition of the sterol pathway we show augmented protection against viral infection, and in combination with metabolite rescue experiments, we identify the requirement of the mevalonate-isoprenoid branch of the sterol metabolic network in the protective response upon statin or IFNβ treatment. Conditioned media experiments from infected cells support an involvement of secreted type 1 interferon(s) to be sufficient for reducing the sterol pathway upon infection. Moreover, we show that infection of primary macrophages containing a genetic knockout of the major type I interferon, IFNβ, leads to only a partial suppression of the sterol pathway, while genetic knockout of the receptor for all type I interferon family members, ifnar1, or associated signaling component, tyk2, completely abolishes the reduction of the sterol biosynthetic activity upon infection. Levels of the proteolytically cleaved nuclear forms of SREBP2, a key transcriptional regulator of sterol biosynthesis, are reduced upon infection and IFNβ treatment at both the protein and de novo transcription level. The reduction in srebf2 gene transcription upon infection and IFN treatment is also found to be strictly dependent on ifnar1. Altogether these results show that type 1 IFN signaling is both necessary and sufficient for reducing the sterol metabolic network activity upon infection, thereby linking the regulation of the sterol pathway with interferon anti-viral defense responses. These findings bring a new link between sterol metabolism and interferon antiviral response and support the idea of using host metabolic modifiers of innate immunity as a potential antiviral strategy.

Currently, little is known about the crosstalk between the body's immune and metabolic systems that occurs after viral infection. This work uncovers a previously unappreciated physiological role for the cholesterol-metabolic pathway in protecting against infection that involves a molecular link with the protein interferon, which is made by immune cells and known to “interfere” with viral replication. We used a clinically relevant model based on mouse cytomegalovirus (CMV) infection of bone-marrow-derived cells. Upon infection these cells produce high levels of interferon as part of the innate-immune response, which we show in turn signals through the interferon receptor resulting in lowering enzyme levels on the cholesterol pathway. We observed this effect with a range of other viruses, and in each case it leads to a notable drop in the metabolites involved in the cholesterol pathway. We found that the control mechanism involves regulation by interferon of an essential transcription factor, named SREBP-2, which coordinates the gene activity of the cholesterol pathway. This mechanism may explain clinical observations of reduced cholesterol levels in patients receiving interferon treatment. Our initial investigation into how lowered cholesterol might protect against viral infection reveals that the protection is not due to a requirement of the virus for cholesterol itself but instead involves a particular side-branch of the pathway that chemically links lipids to proteins. Drugs such as statins and small interfering RNAs that block this part of the pathway are also shown to protect against CMV infection of cells in culture and in mice. This provides the first example of targeting a host metabolic pathway in order to protect against an acute infection.

Assessment of iron status and the role for iron-replacement therapy in anaemic cancer patients under the care of a specialist palliative care unit

Anaemia is common in advanced cancer, may develop for several reasons, and is not always symptomatic. Our observations of the seemingly indiscriminate prescription of iron-replacement therapy (IRT) for anaemic palliative care patients, and our practice of discontinuing IRT in patients with normal red-cell indices, prompted a study to determine (1) the prevalence of anaemia in our patients, (2) what proportion had iron deficiency, (3) the prevalence and benefits of IRT and (4) the prevalence of side effects attributable to IRT. The prevalence of anaemia was 65%. We found a 9% prevalence of iron deficiency, and suggestive but inconclusive evidence of iron deficiency in a further 41%, but only three (27%) of these patients had typical iron deficiency red-cell indices. Only two patients within the study population were taking IRT. Haemoglobin increased significantly in one, but fell in the other, and both experienced side effects attributable to iron. IRT should neither be indiscriminately prescribed nor withheld for anaemic palliative care patients, and the decision should not be based on red-cell indices alone. When symptomatic anaemia is found in patients whose general condition indicates that IRT would be acceptable, iron status should be fully assessed. A therapeutic trial of IRT may be justified where ferritin is elevated, but other parameters suggest iron deficiency.

A logic-based diagram of signalling pathways central to macrophage activation

Background

The complex yet flexible cellular response to pathogens is orchestrated by the interaction of multiple signalling and metabolic pathways. The molecular regulation of this response has been studied in great detail but comprehensive and unambiguous diagrams describing these events are generally unavailable. Four key signalling cascades triggered early-on in the innate immune response are the toll-like receptor, interferon, NF-κB and apoptotic pathways, which co-operate to defend cells against a given pathogen. However, these pathways are commonly viewed as separate entities rather than an integrated network of molecular interactions.

Results

Here we describe the construction of a logically represented pathway diagram which attempts to integrate these four pathways central to innate immunity using a modified version of the Edinburgh Pathway Notation. The pathway map is available in a number of electronic formats and editing is supported by yEd graph editor software.

Conclusion

The map presents a powerful visual aid for interpreting the available pathway interaction knowledge and underscores the valuable contribution well constructed pathway diagrams make to communicating large amounts of molecular interaction data. Furthermore, we discuss issues with the limitations and scalability of pathways presented in this fashion, explore options for automated layout of large pathway networks and demonstrate how such maps can aid the interpretation of functional studies.

Training multidisciplinary biomedical informatics students: three years of experience

OBJECTIVE

The European INFOBIOMED Network of Excellence recognized that a successful education program in biomedical informatics should include not only traditional teaching activities in the basic sciences but also the development of skills for working in multidisciplinary teams.

DESIGN

A carefully developed 3-year training program for biomedical informatics students addressed these educational aspects through the following four activities: (1) an internet course database containing an overview of all Medical Informatics and BioInformatics courses, (2) a BioMedical Informatics Summer School, (3) a mobility program based on a 'brokerage service' which published demands and offers, including funding for research exchange projects, and (4) training challenges aimed at the development of multi-disciplinary skills.

MEASUREMENTS

This paper focuses on experiences gained in the development of novel educational activities addressing work in multidisciplinary teams. The training challenges described here were evaluated by asking participants to fill out forms with Likert scale based questions. For the mobility program a needs assessment was carried out.

RESULTS

The mobility program supported 20 exchanges which fostered new BMI research, resulted in a number of peer-reviewed publications and demonstrated the feasibility of this multidisciplinary BMI approach within the European Union. Students unanimously indicated that the training challenge experience had contributed to their understanding and appreciation of multidisciplinary teamwork.

CONCLUSION

The training activities undertaken in INFOBIOMED have contributed to a multi-disciplinary BMI approach. It is our hope that this work might provide an impetus for training efforts in Europe, and yield a new generation of biomedical informaticians.

Studies of self-incompatibility in wild tomatoes: I. S-allele diversity in Solanum chilense (Dun.) Reiche [corrected] (Solanaceae)

We characterized the molecular allelic variation of RNases at the self-incompatibility (SI) locus of Solanum chilense Dun. We recovered 30 S-RNase allele sequences from 34 plants representing a broad geographic sample. This yielded a species-wide estimate of 35 (95% likelihood interval 31-40) S-alleles. We performed crosses to confirm the association with SI function of 10 of the putative S-RNase allele sequences. Results in all cases were consistent with the expectation that these sequences represent functional alleles under single-locus gametophytic SI. We used the allele sequences to conduct an analysis of selection, as measured by the excess of nonsynonymous changes per site, and found evidence for adaptive changes both within the traditionally defined hypervariable regions and downstream, near the 3'-end of the molecule.

Differential proteomics analysis of synaptic proteins identifies potential cellular targets and protein mediators of synaptic neuroprotection conferred by the slow Wallerian degeneration (Wlds) gene

Non-somatic synaptic and axonal compartments of neurons are primary pathological targets in many neurodegenerative conditions, ranging from Alzheimer disease through to motor neuron disease. Axons and synapses are protected from degeneration by the slow Wallerian degeneration (Wld(s)) gene. Significantly the molecular mechanisms through which this spontaneous genetic mutation delays degeneration remain controversial, and the downstream protein targets of Wld(s) resident in non-somatic compartments remain unknown. In this study we used differential proteomics analysis to identify proteins whose expression levels were significantly altered in isolated synaptic preparations from the striatum of Wld(s) mice. Eight of the 16 proteins we identified as having modified expression levels in Wld(s) synapses are known regulators of mitochondrial stability and degeneration (including VDAC1, Aralar1, and mitofilin). Subsequent analyses demonstrated that other key mitochondrial proteins, not identified in our initial screen, are also modified in Wld(s) synapses. Of the non-mitochondrial proteins identified, several have been implicated in neurodegenerative diseases where synapses and axons are primary pathological targets (including DRP-2 and Rab GDP dissociation inhibitor beta). In addition, we show that downstream protein changes can be identified in pathways corresponding to both Ube4b (including UBE1) and Nmnat1 (including VDAC1 and Aralar1) components of the chimeric Wld(s) gene, suggesting that full-length Wld(s) protein is required to elicit maximal changes in synaptic proteins. We conclude that altered mitochondrial responses to degenerative stimuli are likely to play an important role in the neuroprotective Wld(s) phenotype and that targeting proteins identified in the current study may lead to novel therapies for the treatment of neurodegenerative diseases in humans.

Gene expression profiling of mid to late secretory phase endometrial biopsies from women with menstrual complaint

OBJECTIVE

The purpose of this study was to test whether a quantitative high-throughput molecular screen can be used to probe human endometrium and initiate the development of molecular diagnostic tools with potential for identification of therapeutic targets in women with menstrual complaints.

STUDY DESIGN

Endometrium was collected from 10 patients with complaint of heavy bleeding, classified into mid or late secretory phase of the menstrual cycle by histologic dating and serum progesterone concentration. Total RNA was extracted and gene activity assessed using high-density oligonucleotide arrays.

RESULTS

Statistical testing identified 83 'signature' genes whose expression levels differentiated the mid and late secretory phases of the menstrual cycle.

CONCLUSION

The results show that the endometrium, a complex heterogeneous tissue, is amenable to high-throughput molecular analyses and this work provides further support for the future application of molecular profiling to clinical diagnosis.

Notification of rheumatic fever in South Africa -- evidence for underreporting by health care professionals and administrators

OBJECTIVE

To determine whether under-reporting of rheumatic fever occurs at hospital, municipal, provincial and national levels of the South African health system.

BACKGROUND

Information on the incidence of rheumatic fever (RF) and the prevalence of rheumatic heart disease (RHD) is required for the prevention of valvular heart disease in developing countries. In South Africa, RF was made a notifiable condition in 1989. It has recently been suggested that the reporting of RF cases may be incomplete, possibly because of underreporting by health care professionals and deficient administration of the disease notification system in South Africa.

METHOD AND RESULTS

We assessed whether underreporting of RF cases occurs by comparing the numbers of RF cases reported per year at hospital, municipal, provincial and national levels from 1990 to 2004. There was a fall in the number of RF cases reported per year at national and provincial level over the 15 years of observation. A detailed analysis of the number of RF cases reported at hospital, municipal and provincial level for a 5-year period showed that more cases were diagnosed in one hospital (serving a smaller population) than were captured at municipal and provincial level (serving a larger population), suggesting underreporting by health care professionals. There were discrepancies in the number of cases reported at municipal, provincial and national level, suggesting poor administration of the notification system.

CONCLUSION

There appears to be underreporting of RF cases by health care professionals, and poor administration of the RF notification system. Health care professionals need to be educated about the statutory requirement to notify all RF cases in South Africa. An effective national disease notification system is required.

GPX-Macrophage Expression Atlas: a database for expression profiles of macrophages challenged with a variety of pro-inflammatory, anti-inflammatory, benign and pathogen insults

BACKGROUND

Macrophages play an integral role in the host immune system, bridging innate and adaptive immunity. As such, they are finely attuned to extracellular and intracellular stimuli and respond by rapidly initiating multiple signalling cascades with diverse effector functions. The macrophage cell is therefore an experimentally and clinically amenable biological system for the mapping of biological pathways. The goal of the macrophage expression atlas is to systematically investigate the pathway biology and interaction network of macrophages challenged with a variety of insults, in particular via infection and activation with key inflammatory mediators. As an important first step towards this we present a single searchable database resource containing high-throughput macrophage gene expression studies.

DESCRIPTION

The GPX Macrophage Expression Atlas (GPX-MEA) is an online resource for gene expression based studies of a range of macrophage cell types following treatment with pathogens and immune modulators. GPX-MEA follows the MIAME standard and includes an objective quality score with each experiment. It places special emphasis on rigorously capturing the experimental design and enables the searching of expression data from different microarray experiments. Studies may be queried on the basis of experimental parameters, sample information and quality assessment score. The ability to compare the expression values of individual genes across multiple experiments is provided. In addition, the database offers access to experimental annotation and analysis files and includes experiments and raw data previously unavailable to the research community.

CONCLUSION

GPX-MEA is the first example of a quality scored gene expression database focussed on a macrophage cellular system that allows efficient identification of transcriptional patterns. The resource will provide novel insights into the phenotypic response of macrophages to a variety of benign, inflammatory, and pathogen insults. GPX-MEA is available through the GPX website at http://www.gti.ed.ac.uk/GPX.

Expression profiling reveals novel innate and inflammatory responses in the jejunal epithelial compartment during infection with Trichinella spiralis

Infection with intestinal nematodes induces profound pathological changes to the gut that are associated with eventual parasite expulsion. We have applied expression profiling as an initial screening process with oligonucleotide microarrays (Affymetrix MG-U74AV2 gene chips) and time course kinetics to investigate gene transcription triggered by the intraepithelial nematode Trichinella spiralis in jejunal epithelium from BALB/c mice. Of the 4,114 genes detected, 2,617 were present in all uninfected and T. spiralis-infected replicates, 8% of which were notably upregulated, whereas 12% were downregulated at the time of worm expulsion (day 14 postinfection). Upregulation of goblet cell mucin gene transcripts intestinal mucin gene 3 (MUC3), calcium chloride channel 5 (CLCA5), and goblet cell gene 4 (GOB4) is consistent with enhanced production and alteration of mucus, whereas a 60- to 70-fold upregulation of transcripts for mast cell proteases 1 and 2 (MCPT-1 and -2) is consistent with intraepithelial mucosal mast cell recruitment. Importantly, there was novel expression of sialyltransferase 4C (SIAT4C), small proline-rich protein 2A (SPRR2A), and resistin-like molecule beta (RELMbeta) on day 14 postinfection. In contrast, DNase I and regenerating protein 3 (REG3) transcripts were substantially downregulated. Time course analyses revealed early (within 48 h of infection) induction of Siat4c, Sprr2A, and Relmbeta and later (within 120 h) induction of Mcpt-1 and -2. The findings demonstrate early innate responses and later inflammatory changes within the epithelium. The early epithelial responses may be associated both with repair (Sprr2A) and with the development of innate immunity (Siat4c and Relmbeta).

Vaccination with inactivated murine gammaherpesvirus 68 strongly limits viral replication and latency and protects type I IFN receptor knockout mice from a lethal infection

Human gammaherpesviruses such as Epstein-Barr virus (EBV) cause lifelong infections and associated diseases, including malignancies, and the development of an effective vaccine against this class of viral infections is of considerable interest. The murine herpesvirus 68 (MHV-68) model provides a useful experimental setting to investigate the immune response to gammaherpesvirus infections and to evaluate the efficacy of vaccination strategies. In this study, we tested a heat-inactivated MHV-68 vaccine in immunocompetent mice as well as in B cell-deficient or type I IFN receptor knockout mice. Vaccination with heat-inactivated MHV-68 protected immunocompetent mice from the acute MHV-68 infection in the lung and strongly reduced the expansion of latently infected cells in the spleen and the development of splenomegaly. A similar inhibition of the acute viral replication in the lung was also observed in vaccinated B cell-deficient mice. Of note, the inactivated MHV-68 vaccine completely protected type I IFN receptor knockout mice from the infection with a lethal dose of MHV-68.

Chronic mild hypoxia protects heart-derived H9c2 cells against acute hypoxia/reoxygenation by regulating expression of the SUR2A subunit of the ATP-sensitive K+ channel

Chronic exposure to lower oxygen tension may increase cellular resistance to different types of acute metabolic stress. Here, we show that 24-h-long exposure to slightly decreased oxygen tension (partial pressure of oxygen (PO2) of 100 mm Hg instead of normal 144 mm Hg) confers resistance against acute hypoxia/reoxygenation-induced Ca2+ loading in heart-derived H9c2 cells. The number of ATP-sensitive K+ (K(ATP)) channels were increased in cells exposed to PO2 = 100 mm Hg relative to cells exposed to PO2 = 144 mm Hg. This was due to an increase in transcription of SUR2A, a K(ATP) channel regulatory subunit, but not Kir6.2, a K(ATP) channel pore-forming subunit. PO2 = 100 mm Hg also increased the SUR2 gene promoter activity. Experiments with cells overexpressing wild type of hypoxia-inducible factor (HIF)-1alpha and dominant negative HIF-1beta suggested that the HIF-1-signaling pathway did not participate in observed PO2-mediated regulation of SUR2A expression. On the other hand, NADH inhibited the effect of PO2 = 100 mm Hg but not the effect of PO2 = 20 mm Hg. LY 294002 and PD 184 352 prevented PO2-mediated regulation of K(ATP) channels, whereas rapamycin was without any effect. HMR 1098 inhibited the cytoprotective effect of PO2 = 100 mm Hg, and a decrease of PO2 from 144 to 100 mm Hg did not change the expression of any other gene, including those involved in stress and hypoxic response, as revealed by Affymetrix high density oligonucleotide arrays. We conclude that slight hypoxia activates HIF-1alpha-independent signaling cascade leading to an increase in SUR2A protein, a higher density of K(ATP) channels, and a cellular phenotype more resistant to acute metabolic stress.

Cost analysis of an intensive home follow-up program for first-time post-myocardial infarction patients and their families

OBJECTIVE

The general goal of this research was to determine the effectiveness of a home follow-up program in order to acquire guidance in how to plan the future structure and contents of post-myocardial infarction (MI) patients' care and rehabilitation. The specific aim of this study was to evaluate the cost-effectiveness of the program in reducing the rate of rehospitalization of first-time post-MI patients when measured at six weeks and six months post-discharge.

HYPOTHESIS

The supportive-educative home follow-up program will prove to be cost-effective by indicating an inverse correlation with the cost of post-MI patients being rehospitalized for unplanned and preventable diagnoses.

DESIGN AND SETTING

Cost analysis, using data from a one year randomized control clinical trial conducted in a small urban hospital in eastern Canada. An experimental post test only control group design, including the process of randomization, was used in this study.

SUBJECTS

62 people admitted with a diagnosis of a first-time acute MI during a one-year period with no co-morbidity likely to affect rehabilitation.

MAIN OUTCOME MEASURES

Health care costs.

RESULTS

Early supportive home follow-up reduced inpatient rehospitalization by more than half (three rehospitalizations vs seven rehospitalizations) and reduced the average length of stay (five days vs seven days). Cost analysis demonstrated that intense home follow-up in the time immediately following patient discharge could still produce cost savings to the health care system.

CONCLUSION

Intensive home follow-up provided a cost-effective alternative to traditional cardiac rehabilitation programs; however, a larger study is required to assess the generalizability of the results and long-term cost effectiveness.

Clinical major option: a model for implementing critical care nursing into baccalaureate preparation

What was initiated as a directive from a provincial government in an attempt to increase the number of critical care nurses has evolved into an exciting educational opportunity for many nurses and student nurses in the year 2000. Between 1993 and 1997 there has been significant downsizing of acute care beds across Canada (Code Blue: Critical Care Nursing in Nova Scotia, 1998). At the same time patient acuity has increased, due to shorter hospital stays, and the number of nurses working full-time has decreased with the increased use of casual nurses. Several studies at both the provincial and national levels report current and future shortages of specialized nurses (emergency, critical care and perioperative). It is expected that this shortage will continue into the future, a shortage that is driven by technological advances, as well as an aging general and nursing population. Continued shortages of these acute care nurses will result in fierce competition for skilled nurses as well as aggressive recruitment and retention strategies (Code Blue: Critical Care Nursing in Nova Scotia, 1998). It is generally agreed within the nursing community that specialty nurses in critical care require a unique body of knowledge that is not acquired in a basic undergraduate nursing program (Fitzsimmons, Hadley, & Shively, 1999). This specialized knowledge can be gained informally through experience; however, it is largely developed in additional formal education programs. The purpose of this article is to outline a strategy for the delivery of specialty education at three educational levels in acute care nursing with three streams: emergency, critical care and perioperative nursing. This clinical major option is to be delivered in partnership among the Queen Elizabeth Hospital II, the Health Science Centre and Dalhousie University School of Nursing, Halifax, Nova Scotia, Canada. This model of offering specialty education in university preparation could be a template for preparing nurses in the new millennium.

Regression of a murine gammaherpesvirus 68-positive b-cell lymphoma mediated by CD4 T lymphocytes

Murine gammaherpesvirus 68-infected S11 cells were injected subcutaneously into nude mice. Adoptively transferred restimulated lymphocytes consistently elicited the regression of S11 tumors. CD4 T lymphocytes were most effective in preventing tumor formation, and immunohistochemistry highlighted populations of CD4 T cells in regressing tumors.

Altered expression of Ape1/ref-1 in germ cell tumors and overexpression in NT2 cells confers resistance to bleomycin and radiation

The human AP endonuclease (Ape1 or ref-1) DNA base excision repair (BER) enzyme is a multifunctional protein that has an impact on a wide variety of important cellular functions including oxidative signaling, transcription factor regulation, and cell cycle control. It acts on mutagenic AP (baseless) sites in DNA as a critical member of the DNA BER repair pathway. Moreover, Ape1/ref-1 stimulates the DNA-binding activity of transcription factors (Fos-Jun, nuclear factor-kappaB, Myb, ATF/cyclic AMP-responsive element binding protein family, HIF-1alpha, HLF, PAX, and p53) through a redox mechanism and thus represents a novel component of signal transduction processes that regulate eukaryotic gene expression. Ape1/ref-1 has also been shown to be closely linked to apoptosis associated with thioredoxin, and altered levels of Ape1/ref-1 have been found in some cancers. In a pilot study, we have examined Ape1/ref-1 expression by immunohistochemistry in sections of germ cell tumors (GCTs) from 10 patients with testicular cancer of various histologies including seminomas, yolk sac tumors, and malignant teratomas. Ape1/ref-1 was expressed at relatively high levels in the tumor cells of nearly all sections. We hypothesized that elevated expression of Ape1/ref-1 is responsible in part for the resistance to therapeutic agents. To answer this hypothesis, we overexpressed the Ape1/ref-1 cDNA in the GCT cell line NT2/D1 using retroviral gene transduction with the vector LAPESN. Using an oligonucleotide cleavage assay and immunohistochemistry to assess Ape1/ref-1 repair activity and expression, respectively, we found that the repair activity and relative Ape1/ref-1 expression in GCT cell lines are directly related. NT2/D1 cells transduced with Ape1/ref-1 exhibited 2-fold higher AP endonuclease activity in the oligonucleotide cleavage assay, and this was reflected in a 2-3-fold increase in protection against bleomycin. Lesser protection was observed with gamma-irradiation. We conclude that: (a) Ape1/ref-1 is expressed at relatively high levels in some GCTs; (b) elevated expression of Ape1/ref-1 in testicular cancer cell lines results in resistance to certain therapeutic agents; and (c) Ape1/ref-1 expression in GCT cell lines determined by immunohistochemistry and repair activity assays parallels the level of protection from bleomycin. We further hypothesize that elevated Ape1/ref-1 levels observed in human testicular cancer may be related to their relative resistance to therapy and may serve as a diagnostic marker for refractory disease. To our knowledge, this is the first example of overexpressing Ape1/ref-1 in a mammalian system resulting in enhanced protection to DNA-damaging agents.

Electro-oculography, electroretinography, visual evoked potentials, and multifocal electroretinography in patients with vigabatrin-attributed visual field constriction

PURPOSE

Symptomatic visual field constriction thought to be associated with vigabatrin has been reported. The current study investigated the visual fields and visual electrophysiology of eight patients with known vigabatrin-attributed visual field loss, three of whom were reported previously. Six of the patients were no longer receiving vigabatrin.

METHODS

The central and peripheral fields were examined with the Humphrey Visual Field Analyzer. Full visual electrophysiology, including flash electroretinography (ERG), pattern electroretinography, multifocal ERG using the VERIS system, electro-oculography, and flash and pattern visual evoked potentials, was undertaken.

RESULTS

Seven patients showed marked visual field constriction with some sparing of the temporal visual field. The eighth exhibited concentric constriction. Most electrophysiological responses were usually just within normal limits; two patients had subnormal Arden electro-oculography indices; and one patient showed an abnormally delayed photopic b wave. However, five patients showed delayed 30-Hz flicker b waves, and seven patients showed delayed oscillatory potentials. Multifocal ERG showed abnormalities that sometimes correlated with the visual field appearance and confirmed that the deficit occurs at the retinal level.

CONCLUSION

Marked visual field constriction appears to be associated with vigabatrin therapy. The field defects and some electrophysiological abnormalities persist when vigabatrin therapy is withdrawn.

Analysis of engraftment, graft-versus-host disease, and immune recovery following unrelated donor cord blood transplantation

Unrelated cord blood (UCB) is being used as a source of alternative hematopoietic stem cells for transplantation with increasing frequency. From November 1994 to February 1999, 30 UCB transplant procedures were performed for both malignant and nonmalignant diseases in 27 children, aged 0.4 to 17.1 years. Patients received either HLA-matched (n = 3) or 1- or 2-antigen-mismatched (n = 27) UCB following 1 of 2 standardized preparative and graft-versus-host disease regimens (hyperfractionated total body irradiation, cyclophosphamide, and antithymocyte globulin [ATG] with cyclosporine A and methotrexate; or busulfan, melphalan, and ATG with cyclosporine A and prednisone). The median time to neutrophil and platelet engraftment was 27 days (12-60 days) and 75 days (33-158 days) posttransplantation, respectively. No correlation was noted between neutrophil and platelet engraftment and nucleated cells per kilogram, CD34(+) cells per kilogram infused, or cytomegalovirus status of recipient. The cumulative probability of acute grade 2 or greater graft-versus-host disease (GVHD) was 37.2%, and of grade 3 or greater GVHD was 8.8%. No patients developed chronic GVHD. CD4, CD19, and natural killer cell recovery was achieved at a median of 12, 6, and 2 months, respectively. CD8 recovery was delayed at a median of 9 months. Normal mitogen response was achieved at 6 to 9 months. The probability of survival, disease-free survival, and event-free survival at 1 year was 52.3% (34.1%-70.5%), 54.7% (34.5%-74.9 %) and 49.6% (29.9%-69.4%), respectively. This series of 30 UCB transplants suggests that although CD8 cell recovery is delayed, the pattern of immune reconstitution with UCB is similar to that reported for other stem cell sources. (Blood. 2000;96:2703-2711)

Separating the retinal electrophysiologic effects of vigabatrin: treatment versus field loss

OBJECTIVE

To separate the retinal electrophysiologic markers associated with vigabatrin-attributed visual field loss (VGB-VFL) from those associated with current vigabatrin therapy.

METHODS

A nonrandomly selected cohort of 8 previous and 18 current vigabatrin users and a reference cohort of 8 never vigabatrin-treated patients with epilepsy receiving other antiepilepsy drugs (AED) underwent electro-oculography (EOG), electroretinography (ERG), and automated static threshold perimetry. A cohort of 22 normal subjects underwent ERG. The validity of the retinal electrophysiologic variables to detect the presence and severity of VGB-VFL was assessed using receiver operator characteristic curves.

RESULTS

Of 26 patients exposed to vigabatrin, 18 exhibited VGB-VFL. No patients receiving alternative AED showed this type of visual field abnormality. The presence and severity of VGB-VFL was significantly associated with the latency (implicit time) and amplitude of the ERG cone function. The amplitude of the cone flicker response was the strongest predictor of VGB-VFL and revealed a sensitivity of 100% at a specificity of 75%. The EOG, the photopic and scotopic ERG, and the latency of the ERG second oscillatory potential (OP2) were not significantly related to the presence of VGB-VFL. Vigabatrin therapy was significantly associated with the photopic amplitude, the scotopic a-wave latency, and the latency of OP2.

CONCLUSION

In patients who cannot perform reliable perimetry, the cone-specific ERG flicker amplitude provides the best screening method for detecting VGB-VFL.

Lung infections: role of apoptosis in host defense and pathogenesis of disease

Apoptosis is a form of cell death that has gained enormous attention during the past few years, and its mechanisms, important to biology and medicine, are being unraveled at an accelerating pace. Apoptosis of lung cells occurs during lung infections and may be either a host defense mechanism or reflect the pathogenesis of the infection. In the first part of this review, the biochemistry and physiology of apoptotic pathways and its regulators are discussed. This is followed by an overview of apoptotic mechanisms in selected lung infections. The implications of apoptosis in host immunity, pathogenesis, and treatment of pulmonary infections will be discussed in this context.

Visual electrophysiological effect of a GABA transaminase blocker

Vigabatrin is an antiepileptic drug for the treatment of partial seizures. The anticonvulsant effect is achieved by irreversible inhibition of the enzyme GABA-transaminase which catalyses the inactivation of GABA. Vigabatrin has been associated with visual field loss and electrophysiological abnormalities. The purpose of the study was to determine any alterations in normal volunteers of the visual field and the visual electrophysiology resulting from a short exposure to vigabatrin. A three-way, double-blind study of placebo, carbamazepine and vigabatrin was undertaken at baseline and on days two, four and nine. Seven subjects completed all three cycles and 14 subjects (six females and eight males; mean age 27.3 years SD 6.7) completed at least one cycle. Static threshold automated perimetry comprised Humphrey Visual Field Analyzer Programs 30-2 and 30/60-2. Electro-oculography and electroretinograms were performed with undilated pupils using the Medelec Ganzfeld stimulator GS2000. The visual field was unaffected by placebo, carbamazepine or vigabatrin. The group mean amplitudes and latencies for the scotopic ERG, 30 Hz flicker ERG and the oscillatory potentials remained unchanged for any cycle. The group mean photopic ERG b-wave latency increased from baseline (p<0.05); no significant change occurred with carbamazepine or placebo. The group mean Arden Index for vigabatrin decreased from baseline to day 9 (p<0.01); no significant differences were present for carbamazepine or placebo. Vigabatrin has a rapid effect on both the photopic ERG and the EOG; however, the changes merely reflect alterations in retinal GABA levels secondary to concomitant blocking of GABA transaminase by existing vigabatrin therapy.

Patient compliance and satisfaction with mechanical devices for preventing deep venous thrombosis after joint replacement

A consecutive series of patients having total joint arthroplasty at a single university hospital were sequentially treated with two mechanical devices for prevention of deep venous thrombosis (DVT). The first 104 patients (group 1) wore thigh-high sequential compression device (SCD). The next 120 patients (group 2) wore a foot pump. Daily documentation of hourly compliance with each respective device was recorded until discharge. A patient satisfaction questionnaire was also obtained. Patient understanding about the devices' function aided compliance (73% compliance in group 1, and 77% in group 2). The satisfaction questionnaire revealed significantly greater satisfaction in group 2 (73%) versus group 1 (55%). Of a subgroup of 35 patients who had used both devices, 24 preferred the foot pump, 7 the SCD, and 4 had no preference. This study showed a higher degree of compliance and satisfaction for foot pumps as prophylaxis against DVT.

Bcl-2 protects against beta-lapachone-mediated caspase 3 activation and apoptosis in human myeloid leukemia (HL-60) cells

We previously demonstrated that beta-lapachone (beta-lap) killed cancer cells solely by apoptosis. Beta-Lap induced apoptosis in HL-60 cells in a dose-dependent manner as measured by flow cytometry and DNA ladder formation. Cell cycle changes, such as accumulations in S and G2-phases, were not observed. Apoptosis was accompanied by activation of caspase 3 and concomitant cleavage of poly(ADP-ribose) polymerase (PARP) to an 89 kDa polypeptide. PARP cleavage was blocked by zDEVD-fmk or zVAD-fmk, caspase-specific cleavage site inhibitors. Retrovirally introduced bcl-2 prevented beta-lap-mediated caspase 3 activation and PARP cleavage and increased the viability of Bcl-2-expressing HL-60 cells compared to cells with vector alone. Various beta-lap-related analogs (e.g., dunnione and naphthoquinone derivatives) induced equivalent apoptosis in HL-60 cells, but no compound was more effective than beta-lap. These data provide further evidence that the primary mode of cell killing by beta-lap is by the initiation and execution of apoptosis in human cancer cells.

High dose chemotherapy with autologous peripheral blood progenitor cell transplantation in an anephric child with multiply recurrent Wilms tumor

PURPOSE

An autologous peripheral blood progenitor cell (APBPC) transplant in an anephric child with multiply recurrent Wilms tumor using a conditioning regimen of high dose chemotherapy in conjunction with hemodialysis (HD) and peritoneal dialysis is described.

PATIENT AND METHODS

The child had a left nephrectomy at 9 months of age for a stage II Wilms tumor. At 6 years of age, she required a right nephrectomy because of progressive, recurrent disease unresponsive to treatment with doxorubicin, actinomycin, and vincristine. She was maintained on peritoneal dialysis. Salvage chemotherapy consisted of 5 cycles of carboplatin and cyclophosphamide after APBPCs were collected after granulocyte colony-stimulating factor mobilization. After a preparative regimen of carboplatin, cyclophosphamide, and etoposide with closely timed HD, peripheral blood progenitor cells were infused and peritoneal dialysis was resumed.

RESULTS

No nonhematopoietic toxicity occurred. Pharmacokinetic studies demonstrated that HD effectively eliminated carboplatin and provided safe, effective plasma concentrations in this anephric patient. Trilineage engraftment occurred by day +10 and the child was discharged from the hospital on day +14. She had a local recurrence on day +194 and died of progressive disease on day +660.

CONCLUSIONS

With dialysis support and dose modification, high-dose chemotherapy followed by APBPC transplantation can be successfully performed in the anephric child. Given the lack of organ toxicity in this patient, increased doses of the drugs used in this preparative regimen may be possible for anephric children.

A positive effect of p21cip1/waf1 in the colony formation from murine myeloid progenitor cells as assessed by retroviral-mediated gene transfer

p21cip1/waf1 is a cyclin dependent kinase inhibitor. We have previously reported stimulation of p21cip1/waf1 by steel factor and GM-CSF in a factor dependent cell line and of p21cip1/waf1 involvement in hematopoiesis in vivo in p21cip1/waf1 gene knockout (-/-) mice. To further assess a role for increased p21cip1/waf1 in hematopoietic progenitor cells, we developed the retroviral vector L(p21cip1)SN to transcriptionally regulate p21cip1/waf1 from the Mo-MLV LTR. L(p21cip1)SN and the control vector LXSN were used to transduce murine bone marrow progenitor cells from p21cip1/waf1 (-/-) and littermate control (+/+) mice, as well as from other mouse strains. Hematopoietic colony formation by transduced cells was assessed in semi-solid culture medium with multiple growth factors. Myeloid colony formation by bone marrow cells from p21cip1/waf1 (-/-) mice was significantly lower than that by (+/+) mouse cells. Transduction of cells with LXSN had no effect on colony formation: however, (-/-) cells transduced with L(p21cip1)SN formed significantly greater numbers of colonies than either LXSN-transduced (-/-) or (+/-) cells. Moreover, L(p21cip1)SN-transduced (+/+) cells formed significantly more colonies than LXSN-transduced (+/+) cells. Increased cloning efficiency of progenitors from normal strains of mice induced by L(p21cip1)SN compared to LXSN-transduced cells was seen whether unseparated or highly purified populations of Sca1+ Lin- marrow cells were used. Gene transfer of L(p21cip1)SN increased the size and number of cells per colony, as well as the number of colonies compared to LXSN gene transfer. No colonies grew from non-transduced, LXSN-, or L(p21cip1)SN-transduced cells when no growth factors were added to the cultures. These results document the positive effect of p21cip1/waf1 in the proliferation and/or differentiation of the murine myeloid progenitor cells that lead to colony formation.

Semiquantitative Epstein-Barr virus (EBV) polymerase chain reaction for the determination of patients at risk for EBV-induced lymphoproliferative disease after stem cell transplantation

Epstein-Barr virus-induced lymphoproliferative disease (EBV-LPD) is a serious and potentially fatal complication after allogeneic stem cell transplantation (SCT). To evaluate levels of EBV DNA in SCT patients, a semiquantitative polymerase chain reaction (PCR) assay was developed. DNA was extracted from peripheral blood leukocytes and diluted, and PCR was performed by using a primer set specific for a well-conserved sequence of the internal repeat 1 region of the EBV genome. Forty-one SCT patients were screened with this method. Thirty-seven patients received allogeneic transplants, of which 18 were T-cell-depleted marrow. Four additional patients received autologous SCT, one of which was T-cell depleted. The mean time of follow-up by EBV PCR was 147 days (range, 47 to 328 days) posttransplant. The range of EBV copies/microg DNA from normal EBV sero-positive donors was 40 to 4,000. Seven patients had >/=40,000 copies of EBV DNA/microg DNA, all of whom were recipients of T-cell-depleted SCT. Five of the seven patients with elevated levels of EBV DNA developed EBV-LPD. Four of these five patients with EBV-LPD had elevated levels of EBV DNA from 1 to 8 weeks before diagnosis. Two patients with EBV-LPD had normal levels of EBV DNA, and two patients with >/=40,000 copies EBV/microg DNA did not develop EBV-LPD. In one patient, clinical resolution of disease correlated with a decrease in EBV DNA and an increase in the level of EBV-specific cytotoxic T-cell precursors. These data indicate that the measurement of EBV viral load with semiquantitative PCR is useful in detecting EBV-LPD in high-risk patients before the onset of clinical symptoms. Because not all patients with elevated levels of EBV DNA develop EBV-LPD, semiquantitative PCR results cannot substitute for clinical, radiographic, and pathological confirmation of this diagnosis.

The myeloid zinc finger gene (MZF-1) delays retinoic acid-induced apoptosis and differentiation in myeloid leukemia cells

The myeloid zinc finger gene, MZF-1, is a hematopoietic transcription factor expressed in developing myeloid cells. To characterize further the role of MZF-1 in myelopoiesis, we used retroviral gene transduction to overexpress MZF-1 in HL-60 cells to produce HL-60-MZF-1 cells. HL-60 cells respond to retinoic acid (RA) with growth inhibition, granulocytic differentiation and apoptosis. However, HL-60-MZF-1 cells exposed to RA continue to proliferate in response to RA as evidenced by a higher percentage of cells in S phase, higher peak cell counts, and later peak cell counts. Morphologic differentiation of the RA-induced HL-60-MZF-1 cells is delayed with half as many of the HL-60-MZF-1 cells compared to the wild-type HL-60 cells that are differentiated after 3 days of RA, although both cells types responded with 80-95% mature granulocytes after 6 days of RA. Apoptosis was delayed in the MZF-1 transduced cells as measured by internucleosomal DNA fragmentation patterns, the terminal transferase end labeling reaction (TUNEL), and quantitation of fragmented DNA by the diphenylamine reaction. Several markers of differentiation were identical in both HL-60 and HL-60-MZF-1 cells including CD11b, CD33, CD34, CD13, CD16 and CD14. However, following 6 days of RA, only half as many HL-60-MZF-1 cells expressed CD18 compared to the wild-type HL-60 cells. Expression of the bcl-2 proto-oncogene transcript and protein was higher in the HL-60-MZF-1 cells compared to wild-type HL-60s and expression persisted for 5 days following RA in the HL-60-MZF-1 cells compared to only 3 days in the parental HL-60 cells suggesting that bcl-2 may contribute to the inhibition of apoptosis. Overexpression of MZF-1 had no effect on PMA-induced monocyte/macrophage differentiation of HL-60 cells. Together these findings indicate that MZF-1 can stimulate cell proliferation and delay RA-induced differentiation and apoptosis in HL-60 cells. MZF-1 may function in a similar role in myelopoiesis allowing myeloid precursors to expand their numbers before going on to terminally differentiate.

Differentiation of LA-N-5 neuroblastoma cells into cholinergic neurons: methods for differentiation, immunohistochemistry and reporter gene introduction

The use of model systems derived from cell lines has been a valuable tool in understanding the molecules and cellular processes that govern differentiation processes (T.R. Breitman, S.E. Selonick, S.J. Collins, Induction of differentiation of the human promyelocytic leukemia cell line (HL-60) by retinoic acid, Proc. Natl. Acad. Sci. USA 77 (1980) 2936-2940 [2]; N. Gomez, S. Traverse, P. Cohen, Identification of a MAP kinase in phaeochromocytoma (PC12) cells, FEBS Lett. 314 (1992) 461-465 [4]). The use of such systems provides an inexpensive, quick and simple way to identify and test molecules that can be further studied in more complex in vivo experiments. Some cell lines such as embryonic stem cells can be induced to differentiate in vitro, however, the differentiation is difficult to control and most often leads to the generation of a wide variety of cell types. Cell lines derived from sources committed to a restricted cell fate provide an opportunity to examine cell growth and differentiation within a specific cell type (G.M. Keller, In vitro differentiation of embryonic stem cells, Curr. Opin. Cell Biol. 7 (1995) 862-869 [10]). In this article we describe a simple system for the differentiation of the human neuroblastoma cell line LA-N-5 into cholinergic neurons using all-trans retinoic acid (G. Han, B. Chang, M.J. Connor, N. Sidell, Enhanced potency of 9-cis versus all-trans retinoic acid to induce the differentiation of human neuroblastoma cells, Differentiation, 59 (1995) 61-69 [5]; D.P. Hill, K.R. Robertson, Characterization of the cholinergic neuronal differentiation of the human neuroblastoma cell line LA-N-5 after treatment with retinoic acid, Dev. Brain Res. 102 (1997) 53-67 [6]; J.A. Robson, N. Sidell, Ultrastructural features of a human neuroblastoma cell line treated with retinoic acid, Neuroscience 14 (1985) 1149-1162 [12]; N. Sidell, C.A. Lucas, G.W. Kreutzberg, Regulation of acetylcholinesterase activity by retinoic acid in a human neuroblastoma cell line, Exp. Cell Res. 155 (1984) 305-309 [14]). These cells provide a setting for the study of cholinergic neuronal differentiation and of the factors that influence that process. We also discuss procedures that can be used to study gene expression in LA-N-5 cells by immunohistochemistry and reporter gene analysis.

Characterization of the cholinergic neuronal differentiation of the human neuroblastoma cell line LA-N-5 after treatment with retinoic acid

Analysis of the molecular factors that control cellular differentiation in mammalian embryos is difficult due to the small amount of material available from embryos and their inaccessibility during gestation. One way to circumvent these limitations is to use model systems that allow the study of differentiation in vitro. In this study we have characterized the response of a human neuroblastoma cell line, LA-N-5, to the differentiation-inducing agent, all-trans retinoic acid (RA) using 23 markers that are characteristic of neural crest cells and some of their derivatives. Following induction with RA, the neural crest-like LA-N-5 cells undergo differentiation into cholinergic neurons with increased expression of a variety of neural-specific markers including neurofilaments, growth associated protein-43, tetanus toxin binding sites, receptors for neurotrophic factors, neuropeptides, choline acetyl transferase, vesicular acetylcholine transporter, and acetylcholinesterase with a concomitant decrease in the expression of non-neuronal markers. These results provide the basis for the use of retinoic acid-induced differentiation of LA-N-5 cells as a model system to study molecular events associated with the differentiation of cholinergic neurons.

Treatment of posttransplant lymphoproliferative disease in the central nervous system of a lung transplant recipient using allogeneic leukocytes

Posttransplant Epstein-Barr virus-related lymphoproliferative disease (PT-LPD) is a common and often fatal complication following solid organ and hematopoietic stem cell transplantation. PT-LPD following solid organ transplantation generally occurs in B cells of recipient origin in contrast to PT-LPD in marrow transplant recipients, which is exclusively of donor origin. The efficacy of adoptive immunotherapy using donor leukocytes to treat PT-LPD in bone marrow transplant recipients has recently been reported. Because PT-LPD in solid organ transplant recipients is generally of recipient origin, the potential application of adoptive immunotherapy of PT-LPD in solid organ recipients obligates the use of either autologous or allogeneic HLA identical leukocytes, with the attendant risk of organ rejection if cells mismatched with the transplanted organ are used. Nonirradiated allogeneic mononuclear cells from an Epstein-Barr virus (EBV)-seropositive, HLA-identical normal sibling were used to treat a monoclonal EBV lymphoma of recipient origin in the central nervous system of a child who had undergone an HLA-mismatched cadaveric lung transplant. The patient received three separate mononuclear cell infusions over a 9-month period, each containing 1 x 10(6) CD3+ mononuclear cells per kilogram. Complete clinical, radiological, and pathological remission was achieved with this treatment regimen. The response correlated with in vivo reconstitution of normal EBV-specific cytotoxic activity and cytotoxic T lymphocyte precursor frequency. Use of allogeneic HLA-compatible mononuclear cells may thus offer an additional mode of therapy for EBV-related lymphoproliferative disease in selected solid organ transplant recipients refractory to conventional therapies.

Outpatient total body irradiation for pediatric patients undergoing stem cell transplantation

We have retrospectively reviewed the ability to safely deliver total body irradiation (TBI) in the outpatient setting in 10 pediatric patients undergoing stem cell transplantation. Patients had a median age of 14 years (range 9-17 years) with diagnoses that included ALL in second remission, AML in second remission, myelodysplastic syndrome, Ewing's sarcoma, and rhabdomyosarcoma. Patients received a total of 1375 cGy or 1440 cGy given in a hyperfractionated schedule (11 or 12 fractions) over a 4-day period. All children were seen in the outpatient clinic daily during TBI and all were housed within a 20 mile radius of our institution during this period. Eight patients achieved good control of nausea and emesis with ondansetron alone while two patients required ondansetron and diphenhydramine. Nine patients received some form of intravenous hydration during this period (hyperalimentation, fluid boluses in clinic, or night-time intravenous fluids). One patient maintained good hydration with oral intake alone. Only one child required admission during this period for persistent nausea and vomiting despite antiemetics and intravenous fluids. A cost approximation suggests that TBI delivered in the outpatient setting resulted in a saving of approximately $2400 per patient. We conclude that TBI administered to children and adolescents in the outpatient setting can be a safe and cost-effective practice.

Down-regulation of apurinic/apyrimidinic endonuclease expression is associated with the induction of apoptosis in differentiating myeloid leukemia cells

The human DNA repair enzyme apurinic/apyrimidinic endonuclease (APE/ref-1) is a multifunctional protein in the DNA base excision repair (BER) pathway that is responsible for repair of apurinic/apyrimidinic (AP) sites in DNA. DNA repair and programmed cell death both function using different mechanisms to protect the organism from the consequences of extensive cellular damage; however, little is known about the relationship of the DNA BER repair pathway to apoptosis. We have determined the relationship of a BER DNA repair enzyme, APE, to apoptosis using the myeloid leukemia cell line HL-60, which can be induced to differentiate down the granulocytic or monocytic/ macrophage pathway. Treatment of HL-60 cells with retinoic acid/DMSO (granulocytic) or phorbol 12-myristate 13-acetate (monocytic) results in apoptosis and in down-regulation of APE expression at both the RNA and protein levels. Moreover, double-labeling experiments using APE immunohistochemistry and the terminal deoxyribonucleotidyl transferase-mediated dUTP-fluorescein nick end labeling assay for apoptosis demonstrate that individual cells undergoing apoptosis lose expression of APE regardless of their state of differentiation. Blocking apoptosis by overexpression of the bcl-2 proto-oncogene in HL-60 cells or by a bcr-abl-related mechanism in K562 cells and subsequent differentiation results in morphological differentiation but no loss of APE expression. These studies establish that down-regulation of APE expression is associated with programmed cell death in cells of the myeloid lineage.

Transjugular intrahepatic portosystemic shunting (TIPS) for treatment of severe hepatic veno-occlusive disease

Severe veno-occlusive disease (VOD) of the liver is a frequent cause of morbidity and mortality in patients undergoing transplantation. While surgical portosystemic shunts have been reported to be useful in the treatment of severe hepatic VOD with intractable ascites, few of these patients are surgical candidates. We report a case of severe VOD after autologous peripheral blood progenitor cell transplantation treated with transjugular intrahepatic portosystemic shunting (TIPS). This procedure resulted in marked improvement in the patient's ascites, coagulation status and urinary output. The safety and efficacy of this non-surgical approach for the treatment of patients with severe VOD requires prospective studies.

Retinoic acid-induced expression of CD38 antigen in myeloid cells is mediated through retinoic acid receptor-alpha

CD38 is a leukocyte differentiation antigen that has been thought to be a phenotypic marker of different subpopulations of T- and B-lymphocytes. In myeloid cells, CD38 is expressed during early stages of differentiation. Virtually no information is available on regulation and functions of CD38. Recently we reported that all-trans-retinoic acid (ATRA) is a potent and highly specific inducer of CD38 expression in human promyelocytic leukemia cells. Here we report that ATRA-induced expression of CD38 antigen in myeloid cells is mediated through retinoic acid-alpha receptor (RAR alpha). ATRA failed to induce CD38 expression in a mutant subclone of the HL-60 myeloid leukemia cell line (designated HL-60R) that is relatively resistant to ATRA-induced granulocytic differentiation. Retroviral vector-mediated transduction of RA receptor (RAR alpha) into this HL-60R subclone completely restored the sensitivity of these cells to ATRA in terms of their ability to express CD38. In contrast, CD38 expression was not inducible by ATRA in HL-60R cells, transfected with a functional RAR beta, RAR gamma, or RXR alpha receptor. Induction of CD38 in acute promyelocytic and acute myeloblastic leukemia cells was independent of ATRA-induced cytodifferentiation. Following culture with ATRA, increased CD38 protein levels were also observed in normal CD34+ bone marrow cells, but not on normal circulating granulocytes. From these results, we conclude that CD38 is ATRA inducible in myeloid leukemia cells and normal CD34+ bone marrow cells. This effect is independent of differentiation and is mediated by RAR alpha in HL-60 cells, suggesting a similar role for RAR alpha in CD38 expression in other hematopoietic cells.

Pediatric bone marrow transplantation

Bone marrow transplantation has become well established in the treatment of malignant and nonmalignant disorders. Steady progress continues in improving survival after transplantation, but many problems remain to be solved. Relapsed disease is a major limitation, and new, more intensive preparative regimens are being evaluated in an effort to improve efficacy and reduce toxicity. The availability of unrelated donors has been improved with continued expansion of the National Marrow Donor Program. Additional alternative sources of marrow actively being investigated include partially matched family members and peripheral blood stem cells. Improved marrow purging techniques are also being studied to allow expanded use of autologous marrow for various malignancies. The use of cytokines to minimize regimen toxicity and as therapeutic agents is also promising. The late effects of bone marrow transplantation, including relapse, chronic graft-versus-host disease, secondary malignancies, and effects on growth and development, are important considerations in the design of new therapeutic strategies.

Retinoic acid-resistant HL-60R cells harbor a point mutation in the retinoic acid receptor ligand-binding domain that confers dominant negative activity

Retinoic acid (RA) induces granulocytic differentiation of acute promyelocytic leukemia (APL) cells and is a useful therapeutic agent for patients with this disease. In the HL-60 promyelocytic leukemia cell line, this RA-induced granulocytic differentiation appears to be directly mediated through the RA receptor (RAR-alpha). We have previously identified a mutant subclone of HL-60 (designated HL-60R) that exhibits relative resistance to RA and that harbors RA receptors with markedly reduced affinity for RA. In the present study, we have now identified the genetic basis for this aberrant RA receptor activity. DNA sequencing of polymerase chain reaction-amplified cDNA products corresponding to the RAR-alpha ligand-binding domain shows a point mutation in RAR-alpha codon 411 in this mutant HL-60R subclone. This specific C-->T mutation generates a termination codon resulting in the truncation of 52 amino acids at the COOH terminal end of RAR-alpha. In cotransfection studies, expression vectors harboring this mutated RAR-alpha exhibit dominant negative activity with respect to the trans-activating function of the normal RAR-alpha. Although our observations are limited to HL-60 cells, similar RA receptor mutations might play an important role in the acquisition of RA resistance in RA-treated APL patients.

Multiple members of the retinoic acid receptor family are capable of mediating the granulocytic differentiation of HL-60 cells

The complex and diverse biological effects of retinoic acid (RA) are mediated through specific receptors that are members of the steroid hormone family of nuclear transcription factors. The RA receptor family consists of multiple structurally distinct RA receptors, which diverge primarily at the NH2-terminal domain. The evolutionary conservation of this divergent region in individual RA receptors among different species together with their tissue-specific patterns of expression suggest that the biological function and activity of the individual RA receptors may be confined to specific tissues. To test this hypothesis in hematopoietic cells, we used retrovirus-mediated gene transduction to introduce the RA receptors RAR-alpha, RAR-beta, and RAR-gamma as well as RXR-alpha into a mutant subclone of the HL-60 promyelocytic leukemia cell line (designated HL-60R) that is relatively resistant to RA-induced granulocytic differentiation. We found that each of these structurally distinct RA receptors could restore sensitivity of the HL-60R cells to RA. A critical threshold number of transduced receptors per cell appears to be necessary to restore this functional activity. Thus, the capability to mediate granulocytic differentiation of HL-60 cells is shared among distinctly different RA receptors.

The nucleotide sequence of rabbit liver transferrin cDNA

The cDNA sequence of rabbit liver transferrin has been determined. The largest cDNA was 2279 base pairs (bp) in size and encoded 694 amino acids consisting of a putative 19 amino acid signal peptide and 675 amino acids of plasma transferrin. The deduced amino acid sequence of rabbit liver transferrin shares 78.5% identity with human liver transferrin and 69.1% and 44.8% identity with porcine and Xenopus transferrins, respectively. At the amino acid level, vertebrate transferrins share 26.4% identity and 56.5% similarity. The most conserved regions correspond to the iron ligands and the anion binding region. Optimal alignment of transferrin sequences required the insertion of a number of gaps in the region corresponding to the N-lobe. In addition, the N-lobes of transferrins share less amino acid sequence similarity than the C-lobes.

Pharmacokinetics and pharmacodynamics of doxacurium in normal patients and in those with hepatic or renal failure

We determined the pharmacokinetics and duration of action of a bolus dose of doxacurium (15 micrograms/kg) in 27 patients anesthetized with isoflurane and nitrous oxide. Nine patients had normal renal and liver functions and were undergoing a variety of surgical procedures, nine were undergoing cadaveric kidney transplantation because of end-stage renal disease, and nine were undergoing cadaveric liver transplantation because of end-stage hepatocellular disease. Plasma concentrations of doxacurium were measured for 6 h after administration using a sensitive and specific capillary gas chromatographic assay. Plasma concentration versus time data were analyzed by a noncompartmental method based on statistical moments. Neuromuscular blockade was assessed by measuring the electromyographic evoked response of the adductor pollicis muscle to train-of-four stimulation of the ulnar nerve. The degree of neuromuscular blockade after doxacurium administration was described as the percent of control of the first train-of-four response. The pharmacokinetic variables were (normal vs hepatic failure vs renal failure, respectively): volume of distribution at steady state (220 +/- 110 vs 290 +/- 60 vs 270 +/- 130 mL/kg [mean +/- SD]), plasma clearance (2.7 +/- 1.6 vs 2.3 +/- 0.4 vs 1.2 +/- 0.7 mL.kg-1.min-1), mean residence time (95.2 +/- 57 vs 129.4 +/- 30 vs 270 +/- 210 min), and elimination half-life (99 +/- 54 vs 115 +/- 31 vs 221 +/- 156 min). Plasma clearance and mean residence time differed significantly between patients with renal failure and control patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Retinoic acid receptors in myeloid leukemia: characterization of receptors in retinoic acid-resistant K-562 cells

Although mRNA for the retinoic acid receptor alpha (RAR-alpha) is expressed in many different myeloid leukemias, most of these leukemia cells exhibit little if any phenotypic response when exposed to retinoic acid (RA). To determine whether such RA resistance is related to altered RA receptor structure or function, we performed a detailed analysis of nuclear RA receptors in RA-resistant K-562 cells. These cells exhibit RA receptors of the same approximate molecular weight and similar kd as those exhibited by the RA-sensitive HL-60 leukemia cell line, but the number of RA receptors in the RA-resistant K-562 cells (80 per cell) is significantly lower than that exhibited by RA-sensitive HL-60 cells (550 per cell). Retroviral-mediated transduction of RAR-alpha cDNA into K-562 significantly increased the number of RA receptors to 2,000 per cell. These RAR-alpha-transduced K-562 cells, when incubated with RA, exhibit diminished cell proliferation associated with decreased c-myc expression and an accumulation of cells in G0/G1. In addition, these RA-treated cells exhibit downregulation of the CD15 surface antigen and a slight increase in hemoglobin production but manifest no other evidence of significant erythroid, megakaryocytic, or myeloid differentiation. These results indicate that an elevated number of nuclear RA receptors can be involved in altering proliferation but not necessarily the differentiation of certain RA-treated myeloid leukemia cells.