Non-transcriptional IRF7 interacts with NF-κB to inhibit viral inflammation

Interferon (IFN) regulatory factors (IRF) are key transcription factors in cellular antiviral responses. IRF7, a virus-inducible IRF, expressed primarily in myeloid cells, is required for transcriptional induction of interferon α and antiviral genes. IRF7 is activated by virus-induced phosphorylation in the cytoplasm, leading to its translocation to the nucleus for transcriptional activity. Here, we revealed a nontranscriptional activity of IRF7 contributing to its antiviral functions. IRF7 interacted with the pro-inflammatory transcription factor NF-κB-p65 and inhibited the induction of inflammatory target genes. Using knockdown, knockout, and overexpression strategies, we demonstrated that IRF7 inhibited NF-κB-dependent inflammatory target genes, induced by virus infection or toll-like receptor stimulation. A mutant IRF7, defective in transcriptional activity, interacted with NF-κB-p65 and suppressed NF-κB-induced gene expression. A single-action IRF7 mutant, active in anti-inflammatory function, but defective in transcriptional activity, efficiently suppressed Sendai virus and murine hepatitis virus replication. We, therefore, uncovered an anti-inflammatory function for IRF7, independent of transcriptional activity, contributing to the antiviral response of IRF7.

Generation of induced pluripotent stem cell line NIMHi010-A from dermal fibroblast cells of a healthy individual

In this study, we have established human induced pluripotent stem cell (hiPSC) line, NIMHi010-A of a 42-year-old healthy donor. The iPSC line was generated from human dermal fibroblasts using Sendai viruses carrying reprogramming factors c-MYC, SOX2, KLF4, and OCT4 under a feeder-free culture system. The generated hiPSC line expressed typical pluripotency markers, displayed a normal karyotype, and demonstrated the potential to differentiate into the three germ layers. This hiPSC line will serve as a healthy control model for physiological processes and drug screening of Asian origin from Indian population.

Safety of GMP-compliant iPSC lines generated by Sendai virus transduction is dependent upon clone identity and sex of the donor

Human induced pluripotent stem cells (hiPSCs) are a potential source of somatic cells for cell therapies due to their ability to self-renew and differentiate into various cells of the body. To date, the clinical application of hiPSCs has been limited due to safety issues. The present study aims to standardize the safety procedure of the derivation of GMP-compliant induced pluripotent stem cell (iPSC) lines from human fibroblasts. The hiPSC lines were generated using the nonintegrative Sendai virus method to incorporate Yamanaka reprogramming factors (OCT3/4, SOX2, KLF4 and c-MYC) into cells. A constant temperature was maintained during the cell culture, including all stages of the culture after transduction with Sendai virus. Pluripotency was proved in six independently generated hiPSC lines from adult female (47 years old) and male (57 years old) donors' derived fibroblasts via alkaline phosphatase live (ALP) staining, qPCR, and immunocytochemistry. The hiPSC lines showed a gradual decrease in the presence of the virus with each subsequent passage, and this reduction was specific to the hiPSC line. The frequency and probability of chromosomal aberrations in hiPSCs were dependent on both the iPSC clone identity and sex of the donor. In summary, the generation of hiPSC for clinical applications requires safety standards application (biosafety protocol, quality control of hiPSC lines, viral and genetic integrity screening) from the first stages of the clonal selection of hiPSC from the same donor.

Viral Size Modulates Sendai Virus Binding to Cholesterol-Stabilized Receptor Nanoclusters

Binding to the host membrane is the initial infection step for animal viruses. Sendai virus (SeV), the model respirovirus studied here, utilizes sialic-acid-conjugated glycoproteins and glycolipids as receptors for binding. In a previous report studying single virus binding to supported lipid bilayers (SLBs), we found a puzzling mechanistic difference between the binding of SeV and influenza A virus (strain X31, IAVX31). Both viruses use similar receptors and exhibit similar cooperative binding behavior, but whereas IAVX31 binding was altered by SLB cholesterol concentration, which can stabilize receptor nanoclusters, SeV was not. Here, we propose that differences in viral size distributions can explain this discrepancy; viral size could alter the number of virus-receptor interactions in the contact area and, therefore, the sensitivity to receptor nanoclusters. To test this, we compared the dependence of SeV binding on SLB cholesterol concentration between size-filtered and unfiltered SeV. At high receptor density, the unfiltered virus showed little dependence, but the size-filtered virus exhibited a linear cholesterol dependence, similar to IAVX31. However, at low receptor densities, the unfiltered virus did exhibit a cholesterol dependence, indicating that receptor nanoclusters enhance viral binding only when the number of potential virus-receptor interactions is small enough. We also studied the influence of viral size and receptor nanoclusters on viral mobility following binding. Whereas differences in viral size greatly influenced mobility, the effect of receptor nanoclusters on mobility was small. Together, our results highlight the mechanistic salience of both the distribution of viral sizes and the lateral distribution of receptors in a viral infection.

Human induced pluripotent stem cells generated from epilepsy patients for use as in vitro models for drug screening

In this paper, we describe the generation and validation of human induced pluripotent stem cell (hiPSC) lines from peripheral blood mononuclear cells (PBMCs) from 6 epilepsy patients using a non-integrative Sendai virus vector. These human cellular models will enable patient-specific drug screening to improve outcomes for individuals with this disorder.

Porcine iPSC Generation: Testing Different Protocols to a Successful Application

Stem cell therapy has an unparalleled potential to treat blood cancers, cardiovascular diseases and neurodegenerative conditions, among others. However, stem cell therapeutics must overcome multiple requirements before reaching clinical trials, including large animal safety and efficacy studies. In cardiovascular diseases swine models are the most widely adopted due to its great translational potential to humans. In this chapter, we will describe several protocols to induce iPSC dedifferentiation in swine fibroblasts, as well as conditioning treatments that may help in the reprogramming process.

Solid-Phase Binding Assay for Ganglioside Binding of Human Respiroviruses

Human parainfluenza virus types 1 (hPIV-1) and 3 (hPIV-3) belong to the family Paramyxoviridae, subfamily Paramyxoviridae, and genus Respirovirus. The viruses enter by utilizing glycoproteins or glycosphingolipids (gangliosides) containing sialic acid on the cell membrane. We developed a solid-phase binding assay to evaluate hPIV-1, hPIV-3, and Sendai virus' abilities to bind to different types of gangliosides. hPIV1 and hPIV3 show strong binding to neolacto-series gangliosides containing a non-reducing terminal sialic acid residue and different specificity regarding the sialic acid linkages. This solid-phase binding assay is suitable to evaluate other orthomyxoviruses and paramyxoviruses' binding specificities utilizing sialic acids.

Basal epithelial stem cells cross an alarmin checkpoint for postviral lung disease

Epithelial cells are charged with protection at barrier sites, but whether this normally beneficial response might sometimes become dysfunctional still needs definition. Here, we recognized a pattern of imbalance marked by basal epithelial cell growth and differentiation that replaced normal airspaces in a mouse model of progressive postviral lung disease due to the Sendai virus. Single-cell and lineage-tracing technologies identified a distinct subset of basal epithelial stem cells (basal ESCs) that extended into gas-exchange tissue to form long-term bronchiolar-alveolar remodeling regions. Moreover, this cell subset was selectively expanded by crossing a cell-growth and survival checkpoint linked to the nuclear-localized alarmin IL-33 that was independent of IL-33 receptor signaling and instead connected to autocrine chromatin accessibility. This mechanism creates an activated stem-progenitor cell lineage with potential for physiological or pathological function. Thus, conditional loss of Il33 gene function in basal epithelial cells disrupted the homeostasis of the epithelial barrier at skin and gut sites but also markedly attenuated postviral disease in the lung based on the downregulation of remodeling and inflammation. Thus, we define a basal ESC strategy to deploy innate immune machinery that appears to overshoot the primordial goal of self-defense. Our findings reveal new targets to stratify and correct chronic and often deadly postviral disease.

Generation and characterization of the induced pluripotent stem cell line SHCDNi004-A from a ten-year-old Chinese boy with X-linked mental retardation in IL1RAPL1 deficiency

Mental retardation, X-linked 21/34 (MRX21/34), is a rare intellectual disability disease caused by mutations in the IL1RAPL1 (Interleukin-1 Receptor Accessory Protein-Like 1) gene. Using Sendai virus-mediated reprogramming, we established an induced pluripotent stem cell (iPSC) line from PBMCs collected from a ten-year-old boy with MRX21/34. The iPSCs showed stable amplification, expressed pluripotent genes, displayed a normal karyotype, and had characteristics of trilineage differentiation potential in an in vitro differentiation assay.

Generation of an urine-derived induced pluripotent stem cell line from a 6-year old X-linked adrenoleukodystrophy (X-ALD) patient

The gene mutations of the ATP-binding-cassette transporter subfamily D member 1 (ABCD1) can lead to the inherited neuro-metabolic malfunction disease X-linked adrenoleukodystrophy (X-ALD). Human urine cells from a 6-year-old male X-ALD patient harboring a ABCD1 gene frameshift (c.2013insA, Xq28) were reprogrammed into the induced pluripotent stem cell (iPSC) line WMUi014-A with Sendai virus reprogramming kit containing OCT4, SOX2, c-MYC, and KLF4 Yamanaka factors. The established iPSCs in vitro stably expressed pluripotent markers, had differentiation potential into three germ layers, and maintained a normal 44 + XY karyotype.

Derivation of iPSC lines from three young healthy donors of Caucasian origin (NUIGi035-A; NUIGi036-A; NUIGi037-A)

The induced pluripotent stem cell (iPSC) technology has offered an unprecedented opportunity for disease modelling and drug discovery. Here we used non-integrating Sendai viral method and derived iPSCs from three young healthy Caucasian donors. All iPSCs expressed pluripotency markers highly and could be differentiated into three germ lineages. They possess normal karyotype which was confirmed by whole genome SNP array. The availability of the healthy control iPSCs offers an opportunity for phenotypic comparison and genome editing for a variety of diseases.

Derivation of two iPSC lines from a sporadic ASD patient (NUIGi033-A) and a paternal control (NUIGi034-A)

Hundreds of rare risk factors have been identified for ASD, however, the underlying causes for ~70% of sporadic cases are unknown. Sporadic ASD models are thus essential for validating phenotypic commonality and drug suitability to the majority of patients. Here, we derived induced pluripotent stem cells (iPSCs) from one sporadic ASD child and one paternal control, using non-integrating Sendai viral methods. The iPSCs strongly expressed pluripotency markers and could be differentiated into three germ layers. Their normal karyotype was validated by genome SNP array. The availability of sporadic ASD-derived iPSCs offers an opportunity for phenotypic comparison with genetic ASD models.

SNX5 inhibits RLR-mediated antiviral signaling by targeting RIG-I-VISA signalosome

Upon invading the cell, the viral RNA is recognized by the RIG-I receptor located in the cytoplasm, causing the RIG-I receptor to be activated. The activated RIG-I receptor transmits downstream antiviral signals by interacting with the adaptor protein VISA located on the mitochondria, leading to the production of type Ⅰ interferons and crude inflammatory cytokine genes. Although there have been many studies on antiviral signal transduction of RIG-I receptors in recent years, the mechanism of RIG-I-VISA-mediated antiviral regulation is still not fully understood. In this study, we identified SNX5 as a negative regulator of RLR-mediated antiviral signaling. Our results show that overexpression of SNX5 inhibits viral-induced activation of the IFN-β promoter, ISRE, NF-κB, and IRF3, whereas RNAi knockdown of SNX5 expression shows opposite results. We also found that overexpression of SNX5 enhanced RIG-I's K48 ubiquitination and attenuated its K63 ubiquitination, resulting in inhibition of virus-induced RIG-I expression. Besides, further studies show that SNX5 overexpression weakens the interaction between VISA and TRAF2/5. Our findings suggest that SNX5 negatively regulates RLR-mediated antiviral signaling by targeting the RIG-I-VISA signalosome and provide new evidence for the negative regulation of RIG-I-mediated innate immune response mechanisms.

High-Throughput Screening Identifies Mixed-Lineage Kinase 3 as a Key Host Regulatory Factor in Zika Virus Infection

The Zika virus (ZIKV) life cycle involves multiple steps and requires interactions with host factors. However, the inability to systematically identify host regulatory factors for ZIKV has hampered antiviral development and our understanding of pathogenicity. Here, using a bioactive compound library with 2,659 small molecules, we applied a high-throughput and imaging-based screen to identify host factors that modulate ZIKV infection. The screen yielded hundreds of hits that markedly inhibited or potentiated ZIKV infection in SNB-19 glioblastoma cells. Among the hits, URMC-099, a mixed-lineage kinase 3 (MLK3) inhibitor, significantly facilitated ZIKV replication in both SNB-19 cells and the neonatal mouse brain. Using gene silencing and overexpression, we further confirmed that MLK3 was a host restriction factor against ZIKV. Mechanistically, MLK3 negatively regulated ZIKV replication through induction of the inflammatory cytokines interleukin-6 (IL-6), IL-8, tumor necrosis factor alpha (TNF-α), and monocyte chemoattractant protein 1 (MCP-1) but did not modulate host interferon-related pathways. Importantly, ZIKV activated the MLK3/MKK7/Jun N-terminal protein kinase (JNK) pathway in both SNB-19 cells and neonatal mouse brain. Together, these findings reveal a critical role for MLK3 in regulating ZIKV infection and facilitate the development of anti-ZIKV therapeutics by providing a number of screening hits.IMPORTANCE Zika fever, an infectious disease caused by the Zika virus (ZIKV), normally results in mild symptoms. Severe infection can cause Guillain-Barré syndrome in adults and birth defects, including microcephaly, in newborns. Although ZIKV was first identified in Uganda in 1947 in rhesus monkeys, a widespread epidemic of ZIKV infection in South and Central America in 2015 and 2016 raised major concerns. To date, there is no vaccine or specific medicine for ZIKV. The significance of our research is the systematic discovery of small molecule candidates that modulate ZIKV infection, which will allow the development of antiviral therapeutics. In addition, we identified MLK3, a key mediator of host signaling pathways that can be activated during ZIKV infection and limits virus replication by inducing multiple inflammatory cytokines. These findings broaden our understanding of ZIKV pathogenesis.

FKBP8 inhibits virus-induced RLR-VISA signaling

The mitochondrial antiviral signal protein mitochondrial antiviral signaling protein, also known as virus-induced signaling adaptor (VISA), plays a key role in regulating host innate immune signaling pathways. This study identifies FK506 binding protein 8 (FKBP8) as a candidate interacting protein of VISA through the yeast two-hybrid technique. The interaction of FKBP8 with VISA, retinoic acid inducible protein 1 (RIG-I), and IFN regulatory factor 3 (IRF3) was confirmed during viral infection in mammalian cells by coimmunoprecipitation. Overexpression of FKBP8 using a eukaryotic expression plasmid significantly attenuated Sendai virus-induced activation of the promoter interferons β (IFN-β), and transcription factors nuclear factor κ-light chain enhancer of activated B cells (NF-κB) and IFN-stimulated response element (ISRE). Overexpression of FKBP8 also decreased dimer-IRF3 activity, but enhanced virus replication. Conversely, knockdown of FKBP8 expression by RNA interference showed opposite effects. Further studies indicated that FKBP8 acts as a negative interacting partner to regulate RLR-VISA signaling by acting on VISA and TANK binding kinase 1 (TBK1). Additionally, FKBP8 played a negative role on virus-induced signaling by inhibiting the formation of TBK1-IRF3 and VISA-TRAF3 complexes. Notably, FKBP8 also promoted the degradation of TBK1, RIG-I, and TRAF3 resulting from FKBP8 reinforced Sendai virus-induced endogenous polyubiquitination of RIG-I, TBK1, and TNF receptor-associated factor 3 (TRAF3). Therefore, a novel function of FKBP8 in innate immunity antiviral signaling regulation was revealed in this study.

Reprogramming human dermal fibroblast into induced pluripotent stem cells using nonintegrative Sendai virus for transduction

INTRODUCTION

Induced pluripotent stem cells (iPSC) that exhibit embryonic stem cell-like properties with unlimited self-renewal and multilineage differentiation properties, are a potential cell source in regenerative medicine and cell-based therapy. Although retroviral and lentiviral transduction methods to generate iPSC are well established, the risk of mutagenesis limits the use of these products for therapeutic applications.

MATERIALS AND METHODS

In this study, reprogramming of human dermal fibroblasts (NHDF) into iPSC was carried out using non-integrative Sendai virus for transduction. The iPSC clones were characterised based on the morphological changes, gene expression of pluripotency markers, and spontaneous and directed differentiation abilities into cells of different germ layers.

RESULTS

On day 18-25 post-transduction, colonies with embryonic stem cell-like morphology were obtained. The iPSC generated were free of Sendai genome and transgene after passage 10, as confirmed by RT-PCR. NHDF-derived iPSC expressed multiple pluripotency markers in qRT-PCR and immunofluorescence staining. When cultured in suspension for 8 days, iPSC successfully formed embryoid body-like spheres. NHDF-derived iPSC also demonstrated the ability to undergo directed differentiation into ectoderm and endoderm.

CONCLUSION

NHDF were successfully reprogrammed into iPSC using non-integrating Sendai virus for transduction.

Virus Infection Triggers MAVS Polymers of Distinct Molecular Weight

The mitochondrial antiviral signaling (MAVS) adaptor protein is a central signaling hub required for cells to mount an antiviral response following virus sensing by retinoic acid-inducible gene I (RIG-I)-like receptors. MAVS localizes in the membrane of mitochondria and peroxisomes and in mitochondrial-associated endoplasmic reticulum membranes. Structural and functional studies have revealed that MAVS activity relies on the formation of functional high molecular weight prion-like aggregates. The formation of protein aggregates typically relies on a dynamic transition between oligomerization and aggregation states. The existence of intermediate state(s) of MAVS polymers, other than aggregates, has not yet been documented. Here, we used a combination of non-reducing SDS-PAGE and semi-denaturing detergent agarose gel electrophoresis (SDD-AGE) to resolve whole cell extract preparations to distinguish MAVS polymerization states. While SDD-AGE analysis of whole cell extracts revealed the formation of previously described high molecular weight prion-like aggregates upon constitutively active RIG-I ectopic expression and virus infection, non-reducing SDS-PAGE allowed us to demonstrate the induction of lower molecular weight oligomers. Cleavage of MAVS using the NS3/4A protease revealed that anchoring to intracellular membranes is required for the appropriate polymerization into active high molecular weight aggregates. Altogether, our data suggest that RIG-I-dependent MAVS activation involves the coexistence of MAVS polymers with distinct molecular weights.

Cysteinyl leukotriene receptor 1 expression identifies a subset of neutrophils during the antiviral response that contributes to postviral atopic airway disease

BACKGROUND

Viral respiratory tract infections increase the risk of development and exacerbation of atopic disease. Previously, we demonstrated the requirement for a neutrophil (PMN) subset expressing CD49d to drive development of postviral atopic airway disease in mice.

OBJECTIVE

We sought to determine whether human CD49d⁺ PMNs are present in the nasal mucosa during acute viral respiratory tract infections and further characterize this PMN subset in human subjects and mice.

METHODS

Sixty subjects (5-50 years old) were enrolled within 4 days of acute onset of upper respiratory symptoms. Nasal lavage for flow cytometry and nasal swabs for viral PCR were performed at enrollment and during convalescence. The Sendai virus mouse model was used to investigate the phenotype and functional relevance of CD49d⁺ PMNs.

RESULTS

CD49d⁺ PMN frequency was significantly higher in nasal lavage fluid during acute respiratory symptoms in all subjects (2.9% vs 1.0%, n = 42, P < .001). In mice CD49d⁺ PMNs represented a "proatopic" neutrophil subset that expressed cysteinyl leukotriene receptor 1 (CysLTR1) and produced TNF, CCL2, and CCL5. Inhibition of CysLTR1 signaling in the first days of a viral respiratory tract infection was sufficient to reduce accumulation of CD49d⁺ PMNs in the lungs and development of postviral atopic airway disease. Similar to the mouse, human CD49d⁺ PMNs isolated from nasal lavage fluid during a viral respiratory tract infection expressed CysLTR1.

CONCLUSION

CD49d and CysLTR1-coexpressing PMNs are present during symptoms of an acute viral respiratory tract infection in human subjects. Further study is needed to examine selective targeting of proatopic neutrophils as a potential therapeutic strategy to prevent development of postviral atopic airway disease.

MAVS activates TBK1 and IKKε through TRAFs in NEMO dependent and independent manner

Mitochondrial antiviral-signaling protein (MAVS) transmits signals from RIG-I-like receptors after RNA virus infections. However, the mechanism by which MAVS activates downstream components, such as TBK1 and IKKα/β, is unclear, although previous work suggests the involvement of NEMO or TBK1-binding proteins TANK, NAP1, and SINTBAD. Here, we report that MAVS-mediated innate immune activation is dependent on TRAFs, partially on NEMO, but not on TBK1-binding proteins. MAVS recruited TBK1/IKKε by TRAFs that were pre-associated with TBK1/IKKε via direct interaction between the coiled-coil domain of TRAFs and the SDD domain of TBK1/IKKε. TRAF2-/-3-/-5-/-6-/- cells completely lost RNA virus responses. TRAFs' E3 ligase activity was required for NEMO activation by synthesizing ubiquitin chains that bound to NEMO for NF-κB and TBK1/IKKε activation. NEMO-activated IKKα/β were important for TBK1/IKKε activation through IKKα/β-mediated TBK1/IKKε phosphorylation. Moreover, individual TRAFs differently mediated TBK1/IKKε activation and thus fine-tuned antiviral immunity under physiological conditions.

PKACs attenuate innate antiviral response by phosphorylating VISA and priming it for MARCH5-mediated degradation

Sensing of viral RNA by RIG-I-like receptors initiates innate antiviral response, which is mediated by the central adaptor VISA. How the RIG-I-VISA-mediated antiviral response is terminated at the late phase of infection is enigmatic. Here we identified the protein kinase A catalytic (PKAC) subunits α and β as negative regulators of RNA virus-triggered signaling in a redundant manner. Viral infection up-regulated cellular cAMP levels and activated PKACs, which then phosphorylated VISA at T54. This phosphorylation abrogated virus-induced aggregation of VISA and primed it for K48-linked polyubiquitination and degradation by the E3 ligase MARCH5, leading to attenuation of virus-triggered induction of downstream antiviral genes. PKACs-deficiency or inactivation by the inhibitor H89 potentiated innate immunity to RNA viruses in cells and mice. Our findings reveal a critical mechanism of attenuating innate immune response to avoid host damage at the late phase of viral infection by the house-keeping PKA kinase.

VISA is a central adaptor protein required for innate immune response to RNA virus. Phosphorylation of VISA by protein kinase A leads to its polyubiquitination and degradation by the E3 ligase MARCH5 at the late phase of viral infection, which provides a critical control mechanism for the host to avoid excessive and harmful immune response.

Efficient Generation of Induced Pluripotent Stem and Neural Progenitor Cells From Acutely Harvested Dura Mater Obtained During Ventriculoperitoneal Shunt Surgery

BACKGROUND

The dura mater can be easily biopsied during most cranial neurosurgical operations. We describe a protocol that allows for robust generation of induced pluripotent stem cells (iPSCs) and neural progenitors from acutely harvested dura mater.

OBJECTIVE

To generate iPSCs and neural progenitor cells from dura mater obtained during ventriculoperitoneal shunt surgery.

METHODS

Dura was obtained during ventriculoperitoneal shunt surgery for normal pressure hydrocephalus from a 60-year-old patient with severe cognitive impairment. Fibroblasts were isolated from the dural matrix and transduced with nonintegrating Sendai virus for iPSC induction. A subset of successfully generated iPSC clones underwent immunocytochemical analysis, teratoma assay, karyotyping, and targeted neural differentiation.

RESULTS

Eleven iPSC clones were obtained from the transduction of an estimated 600,000 dural fibroblasts after 3 passages. Three clones underwent immunocytochemical analysis and were shown to express the transcription factors OCT-4, SOX2, and the embryonic cell markers SSEA-4, TRA-1-60, and Nanog. Two clones were tested for pluripotency and formed teratomas at the injection site in immunodeficient mice. Three clones underwent chromosomal analysis and were found to have a normal metaphase spread and karyotype. One clone underwent targeted neural differentiation and formed neural rosettes as well as TuJ1/SOX1-positive neural progenitor cells.

CONCLUSIONS

IPSCs and neural progenitor cells can be efficiently derived from the dura of patients who need to undergo cranial neurosurgical operations. IPSCs were obtained with a nonintegrating virus and exhibited a normal karyotype, making them candidates for future autotransplantation after targeted differentiation to treat functional deficits.

Association of Myxoviruses with an Adenosine Diphosphatase / Adenosine Triphosphatase / as Revealed by Chromatography on DEAE-Cellulose and by Density Gradient Centrifugation

Die Assoziation von einem, schon früher beschriebenen Adenosindiphosphat spaltenden Enzym mit den Teilchen von Myxoviren wurde mittels Chromatographie an DEAE-Cellulose und Dichte-Gradient-Zentrifugation von vorgereinigten Präparaten von Newcastle Disease, Sendai und A 2- Influenza-Viren sowie von dem gewebseigenen Enzym bestätigt. Das Enzym ist fähig, auch Adenosintriphosphat zu spalten.

Derivation of transgene-free human induced pluripotent stem cells from human peripheral T cells in defined culture conditions

Recently, induced pluripotent stem cells (iPSCs) were established as promising cell sources for revolutionary regenerative therapies. The initial culture system used for iPSC generation needed fetal calf serum in the culture medium and mouse embryonic fibroblast as a feeder layer, both of which could possibly transfer unknown exogenous antigens and pathogens into the iPSC population. Therefore, the development of culture systems designed to minimize such potential risks has become increasingly vital for future applications of iPSCs for clinical use. On another front, although donor cell types for generating iPSCs are wide-ranging, T cells have attracted attention as unique cell sources for iPSCs generation because T cell-derived iPSCs (TiPSCs) have a unique monoclonal T cell receptor genomic rearrangement that enables their differentiation into antigen-specific T cells, which can be applied to novel immunotherapies. In the present study, we generated transgene-free human TiPSCs using a combination of activated human T cells and Sendai virus under defined culture conditions. These TiPSCs expressed pluripotent markers by quantitative PCR and immunostaining, had a normal karyotype, and were capable of differentiating into cells from all three germ layers. This method of TiPSCs generation is more suitable for the therapeutic application of iPSC technology because it lowers the risks associated with the presence of undefined, animal-derived feeder cells and serum. Therefore this work will lead to establishment of safer iPSCs and extended clinical application.

IFIT5 potentiates anti-viral response through enhancing innate immune signaling pathways

Humans have a distinct combination of IFIT (IFN-induced protein with tetratricopeptide repeats) family orthologs, including IFIT1 (ISG56), IFIT2 (ISG54), IFIT3 (ISG60), and IFIT5 (ISG58). The function of IFIT1/IFIT2/IFIT3 has been intensively investigated. However, little is known about the role of IFIT5 in any cellular processes. In this study, we reported that both the mRNA and protein levels of IFIT5 are up-regulated in response to RNA virus infection or polyinosinic-cytidylic acid stimulation. Ectopic expression of IFIT5 could synergize IRF3- and NF-κB-mediated gene expression, whereas knockdown of IFIT5 impairs the transcription of these genes. Consistently, anti-viral responses of host cells are significantly increased or decreased in the presence or absence of IFIT5. Mechanistically, IFIT5 co-localizes partly with mitochondria and interacts with RIG-I and MAVS. Our study identified that IFIT5 is an important enhancer in innate immune response.

Human bocavirus VP2 upregulates IFN-β pathway by inhibiting ring finger protein 125-mediated ubiquitination of retinoic acid-inducible gene-I

Precise regulation of innate immunity is crucial for maintaining optimal immune responses against infections. Whereas positive regulation of IFN signaling elicits rapid type I IFNs, negative regulation is equally important in preventing the production of superfluous IFNs that can be hazardous to the host. The positive regulators of IFN pathway are known to be the main targets of viruses to antagonize the innate immune system. Whether viruses target the negative regulators of IFN pathway remains to be fully investigated. In this study, we report that the structural protein VP2 of human Bocavirus modulates IFN pathway by targeting the ring finger protein 125 (RNF125), a negative regulator of type I IFN signaling, which conjugates Lys(48)-linked ubiquitination to retinoic acid-inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. VP2 not only upregulated Sendai virus (SeV)-induced IFNB promoter activity, but also enhanced SeV-induced IFN-β production at both mRNA and protein levels. In agreement, the level of Ser(396)-phosphorylated IFN regulatory factor 3 stimulated by SeV was enhanced in the presence of VP2. Furthermore, VP2 was demonstrated to physically interact with RNF125, resulting in the reduction of RNF125-mediated ubiquitination and proteasome-dependent degradation of RIG-I. Additional study indicated that endogenous RIG-I degradation was decreased in VP2-expressing cells. Our study delineates a unique phenomenon for aberrant activation of IFN regulatory factor 3 pathway and may represent a new mechanism underlying viral manipulation of the host immune system.

Anti-tumor effects of inactivated Sendai virus particles with an IL-2 gene on angiosarcoma

Cutaneous angiosarcoma is a life-threatening tumor that is resistant to conventional therapies. The therapeutic effects of Sendai virus particles (hemagglutinating virus of Japan envelope: HVJ-E) carrying IL-2 gene (HVJ-E/IL-2) were examined in a mouse model of angiosarcoma. Intra-tumoral injection of HVJ-E/IL-2 effectively inhibited the growth of angiosarcoma cells (ISOS-1) inoculated in mice and improved tumor-free rates. HVJ-E/IL-2 stimulated local accumulation of CD8 (+) T cells and NK cells and reduced regulatory T cells in regional lymph nodes. Notably, the prevalence of myeloid-derived suppressor cells was lower in HVJ-E/IL-2-treated mice than in HVJ-E-treated mice. HVJ-E/IL-2 treatment promoted IFN-γ production from CD8 (+) T cells in response to tumor cells, more significantly than HVJ-E treatment. Greatly improved tumor-free rates were obtained when sunitinib, a tyrosine kinase inhibitor, was administered in combination with HVJ-E/IL-2. Immunogene therapy with HVJ-E/IL-2 with or without sunitinib could be a promising therapeutic option for cutaneous angiosarcoma.

Systematic analysis of the mechanisms of virus-triggered type I IFN signaling pathways through mathematical modeling

Based on biological experimental data, we developed a mathematical model of the virus-triggered signaling pathways that lead to induction of type I IFNs and systematically analyzed the mechanisms of the cellular antiviral innate immune responses, including the negative feedback regulation of ISG56 and the positive feedback regulation of IFNs. We found that the time between 5 and 48 hours after viral infection is vital for the control and/or elimination of the virus from the host cells and demonstrated that the ISG56-induced inhibition of MITA activation is stronger than the ISG56-induced inhibition of TBK1 activation. The global parameter sensitivity analysis suggests that the positive feedback regulation of IFNs is very important in the innate antiviral system. Furthermore, the robustness of the innate immune signaling network was demonstrated using a new robustness index. These results can help us understand the mechanisms of the virus-induced innate immune response at a system level and provide instruction for further biological experiments.

Elicitation of both anti HIV-1 Env humoral and cellular immunities by replicating vaccinia prime Sendai virus boost regimen and boosting by CD40Lm

For protection from HIV-1 infection, a vaccine should elicit both humoral and cell-mediated immune responses. A novel vaccine regimen and adjuvant that induce high levels of HIV-1 Env-specific T cell and antibody (Ab) responses was developed in this study. The prime-boost regimen that used combinations of replication-competent vaccinia LC16m8Δ (m8Δ) and Sendai virus (SeV) vectors expressing HIV-1 Env efficiently produced both Env-specific CD8⁺ T cells and anti-Env antibodies, including neutralizing antibodies (nAbs). These results sharply contrast with vaccine regimens that prime with an Env expressing plasmid and boost with the m8Δ or SeV vector that mainly elicited cellular immunities. Moreover, co-priming with combinations of m8Δs expressing Env or a membrane-bound human CD40 ligand mutant (CD40Lm) enhanced Env-specific CD8⁺ T cell production, but not anti-Env antibody production. In contrast, priming with an m8Δ that coexpresses CD40Lm and Env elicited more anti-Env Abs with higher avidity, but did not promote T cell responses. These results suggest that the m8Δ prime/SeV boost regimen in conjunction with CD40Lm expression could be used as an immunization platform for driving both potent cellular and humoral immunities against pathogens such as HIV-1.

Granulocyte colony-stimulating factor protects mice during respiratory virus infections

A burst in the production of pro-inflammatory molecules characterizes the beginning of the host response to infection. Cytokines, chemokines, and growth factors work in concert to control pathogen replication and activate innate and adaptive immune responses. Granulocyte colony-stimulating factor (G-CSF) mobilizes and activates hematopoietic cells from the bone marrow, and it has been shown to mediate the generation of effective immunity against bacterial and fungal infections. G-CSF is produced at high levels in the lungs during infection with influenza and parainfluenza viruses, but its role during these infections is unknown. Here we show that during infection of mice with a non-lethal dose of influenza or Sendai virus, G-CSF promotes the accumulation of activated Ly6G⁺ granulocytes that control the extent of the lung pro-inflammatory response. Remarkably, these G-CSF-mediated effects facilitate viral clearance and sustain mouse survival.

[Gene-stem Cell therapy for ischemic stroke]

Besides blood flow restoration, neuroprotection is essential for treating strokes at an acute stage. Both neurotrophic factors (NTFs) and free radical scavengers can act as neuroprotective agents with abilities to inhibit cell death and facilitate cell survival under cerebral ischemia. For example, topical application of glial cell line-derived neurotrophic factor (GDNF) remarkably reduced infarct size and brain edema after middle cerebral artery (MCA) occlusion in rats. Reduction in the infarct size was not found to be related to a change in the cerebral blood flow (CBF), but was accompanied by marked reduction in BrdU-positive cells in the affected area after TdT-mediated dUTP-biotin nick end labeling (TUNEL) for caspses. Thus, GDNF elicited a direct protective effect against ischemic brain damage, but without improving CBF. Sendai virus vectors harboring the GDNF gene led to a remarkable reduction in infract volume without affecting regional CBF but reduced the translocation of apoptosis inducible factor (AIF) from the mitochondria to cytoplasm. Regenerative therapy involving neural stem cells which are intrinsically activated or exogenously transplanted, is an important treatment strategy. To facilitate stem cell migration, an artificial scaffold can be implanted into the injured brain for promoting ischemic brain repair. Addition of NTFs greatly enhanced an intrinsic migration or invasion of stem cells into the scaffold: this strategy could be used in the future for enhancing regenerative potential of brain cells after chronic ischemia-induced brain damage.

Liposome-mediated Gene Therapy in the Kidney

Gene therapy directed to the kidney has been attempted to improve renal disorders such as inherited kidney diseases and common renal diseases that cause interstitial fibrosis, tubular atrophy, and glomerulosclerosis. Viral and non-viral vectors have been tried and been modulated to obtain sufficient transgene expression. However, gene delivery to the kidney is usually difficult because of characteristics of renal cell biology. Among non-viral vectors, the liposome system is a promising procedure for kidney-targeted gene therapy. Using cationic liposome, tubular cells were effectively transduced by retrograde injection of liposome/cDNA complex. Although transgene expression was reportedly modest using cationic liposomes, this method improved renal disease models such as carbonic anhydrase II deficiency and unilateral ureteral obstruction. In contrast, HVJ-liposome system is an effective transfection method to glomerular cells using intra-renal arterial infusion and improved glomerular disease models such as glomerulonephritis and glomerulosclerosis. In addition, intra-renal pelvic injection of DNA by HVJ-liposome system showed transgene expression in interstitial fibroblasts. In kidney-targeted gene therapy, liposome-mediated gene transfer is an attractive method because of its simplicity and reduced toxicity. In spite of modest transgene expression, several renal disease models were successfully modulated by liposome system. Although one limitation of liposome-mediated gene delivery is the duration of transgene expression, the liposome/cDNA complex can be repeatedly administered due to the absence of an immune response.

Effect on vein graft intimal hyperplasia of nuclear factor-kB decoy transfection using the second generation of HVJ vector

AIM

Vein graft stenosis due to intimal hyperplasia (IH) is the main cause of graft failure. We examined possibilities of nuclear factor-kB (NF-kB) expression in vein grafts, and inhibitive effects of NF-kB decoy on the gene expression and subsequent vein graft IH.

METHODS

Fifteen mongrel dogs underwent femoral artery replacement with autogenous vein grafts. Group I: grafts were retrieved at a predetermined time and subjected to NF-kB binding activity assay; Groups II and III: grafts were transfected with scrambled (II-a, III-a) or NF-kB (II-b, III-b) decoy using hemagglutinating virus of Japan envelope before implantation. Grafts were retrieved 7 days after implantation for evaluation of intercellular adhesion molecule-1 (ICAM-1) mRNA expression (Group II) and 4 weeks after implantation for comparison of IH by morphometric analysis (Group III).

RESULTS

NF-kB binding activity was increased in a time-dependent manner, with a peak 2 days after implantation. The ratio between ICAM-1 and glyceraldehyde-3-phosphate dehydrogenase mRNA expression in II-b was significantly lower than that in II-a (0.347 +/- 0.07 versus 0.612+/-0.08; P = 0.047). The ratio of intimal cross-section area to luminal cross-section area of III-b was significantly lower than that of the III-a (0.096+/-0.03 versus 0.461+/-0.11; P = 0.048).

CONCLUSION

NF-kB binding activity in vein grafts increases after implantation, and transfection of NF-kB decoy before implantation may reduce IH through the inhibition of ICAM-1 expression.

[Anticancer immunotherapy using inactivated Sendai virus particles]

Ultraviolet-inactivated, replication-defective Sendai virus particles (Hemagglutinating virus of Japan envelope, HVJ-E) injected into murine colon carcinoma (CT26) tumors growing in syngeneic Balb/c mice eradicated 60-80% of the tumors and obviously inhibited the growth of the remainder. Induced adaptive anti-tumor immune responses were dominant in the tumor eradication process because the effect was abrogated in severe combined immunodeficient (SCID) mice. Murine and human dendritic cells (DCs) underwent dose-dependent maturation by HVJ-E in vitro. Profiles of cytokines secreted by DCs after HVJ-E stimulation showed that the amount of IL-6 released was comparable to that elicited by live HVJ. Real-time RT-PCR and immunohistochemistry revealed that HVJ-E induced a remarkable infiltration of DCs, CD4+ and CD8+ T cells into tumors and CT26 specific cytotoxic T lymphocytes (CTL) were induced. On the other hand, conditioned medium from DCs stimulated by HVJ-E (H-DCCM) rescued CD4+CD25- effector T cell proliferation from Foxp3+CD4+CD25+ regulatory T cell (Treg) mediated suppression and IL-6 was presumably dominant for this phenomenon. We also confirmed such rescue in mice treated with HVJ-E in vivo. Moreover, anti-tumor effect of HVJ-E was significantly reduced by an in vivo blockade of IL-6 signaling. Depending on cancer cell types, it is also expected that HVJ-E eradicates tumor by its direct cytotoxity against cancer cells or activating NK cells. Because it can enhance anti-tumor immunity and simultaneously remove Treg mediated suppression, HVJ-E shows promise as a novel therapeutic for cancer immunotherapy.

Evaluation of a novel vaccine (HVJ-liposome/HSP65 DNA+IL-12 DNA) against tuberculosis using the cynomolgus monkey model of TB

We have developed a novel tuberculosis (TB) vaccine; a combination of the DNA vaccines expressing mycobacterial heat shock protein 65 (HSP65) and interleukin 12 (IL-12) delivered by the hemagglutinating virus of Japan (HVJ)-liposome (HSP65+IL-12/HVJ). This vaccine provided remarkable protective efficacy in mouse and guinea pig models compared to the BCG vaccine, on the basis of an induction of the CTL activity and improvement of the histopathological tuberculosis lesions, respectively. Furthermore, we extended our studies to a cynomolgus monkey model, which is currently the best animal model of human tuberculosis. This novel vaccine provided a higher level of the protective efficacy than BCG based upon the assessment of mortality, the ESR, body weight, chest X-ray findings and immune responses. Furthermore, the combination of HSP65+IL-12/HVJ and BCG by the priming-booster method showed a synergistic effect in the TB-infected cynomolgus monkey (100% survival). These data indicate that our novel DNA vaccine might be useful against Mycobacterium tuberculosis for human clinical trials.

Role of airway epithelial injury in murine orthotopic tracheal allograft rejection

BACKGROUND

Murine tracheal transplantation is a model used to study bronchiolitis obliterans syndrome, a major cause of morbidity and mortality after lung transplantation. Unlike murine heterotopic tracheal transplants, orthotopic transplantation does not cause luminal obliteration despite major histocompatibility antigen mismatch. Repopulation of the tracheal allografts with recipient-derived epithelium confers protection against luminal obliteration. The purpose of this study was to determine whether (1) orthotopic tracheal transplantation showed signs of allograft rejection, and (2) airway epithelial cell injury promoted orthotopic tracheal allograft rejection.

METHODS

Forty isogeneic (C57BL/6 to C57BL/6) and 40 allogeneic (BALB/c to C57BL/6) orthotopic tracheal transplants were performed. Damage to airway epithelial cells was induced by Sendai viral (SdV) infection and tracheal transplantation into non-reepithelializing matrix metalloproteinase-7 knockout (MMP7-KO) recipient mice. Percent fibrosis and lamina propria to cartilage ratio were calculated with computer assistance on harvested allografts.

RESULTS

Allografts showed significantly more intramural fibrosis compared with isografts at 30, 60, and 180 days after transplant without luminal occlusion. Tracheal allografts infected with SdV showed an increase in fibrosis and lamina propria to cartilage ratio compared with noninfected controls. Allografts retrieved from MMP7-KO recipients also showed a significant increase in fibrosis and lamina propria to cartilage ratio.

CONCLUSIONS

Although orthotopic tracheal transplantation does not cause luminal obliteration, it results in increased fibrosis in allografts. Damage to the respiratory epithelium by viral infection or defective reepithelialization after transplant as seen in MMP7-KO recipient mice leads to changes consistent with chronic allograft rejection, suggesting a role for epithelial injury in bronchiolitis obliterans syndrome development.

Involvement of the IκB Kinase (IKK)-Related Kinases Tank-Binding Kinase 1/IKKi and Cullin-Based Ubiquitin Ligases in IFN Regulatory Factor-3 Degradation

Activation of the innate arm of the immune system following pathogen infection relies on the recruitment of latent transcription factors involved in the induction of a subset of genes responsible for viral clearance. One of these transcription factors, IFN regulatory factor 3 (IRF-3), is targeted for proteosomal degradation following virus infection. However, the molecular mechanisms involved in this process are still unknown. In this study, we show that polyubiquitination of IRF-3 increases in response to Sendai virus infection. Using an E1 temperature-sensitive cell line, we demonstrate that polyubiquitination is required for the observed degradation of IRF-3. Inactivation of NEDD8-activating E1 enzyme also results in stabilization of IRF-3 suggesting the NEDDylation also plays a role in IRF-3 degradation following Sendai virus infection. In agreement with this observation, IRF-3 is recruited to Cullin1 following virus infection and overexpression of a dominant-negative mutant of Cullin1 significantly inhibits the degradation of IRF-3 observed in infected cells. We also asked whether the C-terminal cluster of phosphoacceptor sites of IRF-3 could serve as a destabilization signal and we therefore measured the half-life of C-terminal phosphomimetic IRF-3 mutants. Interestingly, we found them to be short-lived in contrast to wild-type IRF-3. In addition, no degradation of IRF-3 was observed in TBK1(-/-) mouse embryonic fibroblasts. All together, these data demonstrate that virus infection stimulates a host cell signaling pathway that modulates the expression level of IRF-3 through its C-terminal phosphorylation by the IkappaB kinase-related kinases followed by its polyubiquitination, which is mediated in part by a Cullin-based ubiquitin ligase.

Optimizing vector application for gene transfer into human hepatoblastoma cells

Gene targeting is currently of distinct interest as an innovative additive treatment option in various malignancies. Its role in pediatric liver tumors has not yet been evaluated thoroughly. For the first time the authors systematically analyzed both lipid-based transfection as well as transduction with adenovirus vectors (Ad) and Sendai virus vectors (SeVV) in order to optimize gene transfer into hepatoblastoma (HB) cells. Two HB cell lines were infected with Ad or SeVV coding for green fluorescent protein (Ad-GFP, SeVV-GFP); transduction efficiencies and apoptosis were assessed using flow cytometry. Furthermore, lipofection of HB cell lines with plasmid-constructs comprising liver-specific promoters was performed using Lipofectamine 2000 and FuGENE 6; lipofection efficiency was monitored by flow cytometry, microscopy, and luciferase activity. The Ad-GFP showed higher transduction rates (61-86%) than the SeVV-GFP (4-24%) depending on the HB cell line used. Infections with first generation SeVV vectors (SeVV-GFP) led to increased target cell apoptosis (7-43%) compared to Ad-GFP (4-16%). The Lipofectamine 2000 revealed a higher transfection efficiency than the FuGENE 6 for both HB cell lines tested. The liver-specific promoters were found to be differently active in the HB cell lines. This study delineates recombinant adenovirus vectors as a promising tool for gene transduction in the HB cells. Furthermore, enhanced activity of the liver-specific promoters in HUH6 cells compared to HepT1 cells supports the observation of varying biological behavior in histologically differing HB tissues.

Identification of trypsin I as a candidate for influenza A virus and Sendai virus envelope glycoprotein processing protease in rat brain

Extracellular cleavage of virus envelope fusion glycoprotein hemagglutinin (HA0) by host trypsin-like proteases is a prerequisite for the infectivity and pathogenicity of human influenza A viruses and Sendai virus. The common epidemic influenza A viruses are pneumotropic, but occasionally cause encephalopathy or encephalitis, although the HA0 processing enzyme in the brain has not been identified. In searching for the brain processing proteases, we identified a processing enzyme in rat brain that was inducible by infection with these viruses. The purified enzyme exhibited an apparent molecular mass of approximately 22 kDa on SDS-PAGE and the N-terminal amino acid sequence was consistent with that of rat pancreatic trypsin I. Its substrate specificities and inhibition profiles were the same as those of pancreatic trypsin I. In situ hybridization and immunohistochemical studies on trypsin I distribution revealed heavy deposits in the brain capillaries, particularly in the allocortex, as well as in clustered neuronal cells of the hippocampus. The purified enzyme efficiently processed the HA0 of human influenza A virus and the fusion glycoprotein precursor of Sendai virus. Our results suggest that trypsin I in the brain potentiates virus multiplication in the pathogenesis and progression of influenza-associated encephalopathy or encephalitis.

Development of High-Throughput Functional Screening of Therapeutic Genes, Using a Hemagglutinating Virus of Japan Envelope Vector

Isolation of effective therapeutic genes is critical for the advancement of gene therapy for various diseases, including vascular diseases and cancers. The goal of the present study was to screen a human cDNA library, using a hemagglutinating virus of Japan envelope (HVJ-E) vector, to isolate candidate genes with potent therapeutic potential. The advantages of a high-throughput functional screening system based on the HVJ-E vector include (1) rapid preparation of the vector containing the DNA library, (2) effective fusion-mediated transfer of the plasmids to various cells with minimal toxicity, and (3) easy cloning of candidate genes by transformation of Escherichia coli. These advantages resulted in a lower probability of damage to isolated clones and in minimization of the time needed to screen for candidate genes. Screening of a human heart library for candidate genes to regulate endothelial cell growth identified three growth-stimulating genes, as evaluated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and c-fos promoter activity, the products of which were more potent than vascular endothelial growth factor. Similarly, two growth-inhibiting genes were identified, the effects of which were similar to angiostatin. Overall, this novel system will help advance our understanding of cell biology and promote the utility of human gene therapy.

Genetic segregation of airway disease traits despite redundancy of calcium-activated chloride channel family members

Complex airway diseases such as asthma and chronic obstructive pulmonary disease exhibit stereotyped traits (especially airway hyperreactivity and mucous cell metaplasia) that are variably expressed in each patient. Here, we used a mouse model for virus-induced long-term expression of these traits to determine whether individual traits can be genetically segregated and thereby linked to separate determinants. We showed that an F2 intercross population derived from susceptible and nonsusceptible mouse strains can manifest individual phenotypic extremes that exhibit one or the other disease trait. Functional genomic analysis of these extremes further indicated that a member of the calcium-activated chloride channel (CLCA) gene family designated mClca3 was inducible with mucous cell metaplasia but not airway hyperreactivity. In confirmation of this finding, we found that mClca3 gene transfer to mouse airway epithelium was sufficient to induce mucous cell metaplasia but not airway hyperreactivity. However, newly developed mClca3(-/-) mice exhibited the same degree of mucous cell metaplasia and airway hyperreactivity as wild-type mice. Bioinformatic analysis of the Clca locus led to the identification of mClca5, and gene transfer indicated that mClca5 also selectively drives mucous cell metaplasia. Thus, in addition to the capacity of CLCA family members to exhibit diverse functional activities, there is also preserved function so that more than one family member mediates mucous cell metaplasia. Nonetheless, Clca expression appears to be a selective determinant of mucous cell metaplasia so that shared homologies between CLCA family members may still represent a useful target for focused therapeutic intervention in hypersecretory airway disease.

Id1 gene transfer confers angiogenic property on fully differentiated endothelial cells and contributes to therapeutic angiogenesis

BACKGROUND

Transplantation of endothelial progenitor cells has been proposed as a potential strategy for therapeutic revascularization. However, the limited endogenous cell pool and the related technical difficulties constitute clinically important disadvantages to autologous transplantation. In this study we investigated whether fully differentiated endothelial cells (ECs) modified with gene transfer of Id1, a helix-loop-helix transcription factor involved in angiogenesis, have the potential to contribute to therapeutic angiogenesis.

METHODS AND RESULTS

The Id1 gene was transferred into human umbilical vein ECs (HUVECs) via a Sendai virus vector. Id1 stimulated migration, proliferation, and capillary-like tube/cord formation of HUVECs. In addition, Id1 reduced serum deprivation-induced HUVEC apoptosis, as shown by FACS analysis with annexin V and TUNEL staining. Transplantation of Id1-overexpressing HUVECs accelerated recovery of blood flow as evaluated by laser-Doppler perfusion imaging, increased capillary density, and improved the rate of limb salvage compared with the transplantation of control HUVECs. Histochemical analysis revealed that the regenerated vascular networks of limbs transplanted with Id1-overexpressing HUVECs contained numerous HUVECs, some of which were in a proliferative state. Untransfected HUVECs were also incorporated with Id1-transfected HUVECs, suggesting the noncell autonomous effect of Id1. Finally, angiopoietin-1 was upregulated in Id1-overexpressing HUVECs and functionally contributed to the in vitro angiogenic effect of Id1.

CONCLUSIONS

Id1 gene transfer conferred HUVECs with an angiogenic property, contributing to neovascularization after transplantation into ischemic lesions. Transplantation of Id1-overexpressing mature ECs may serve as a novel and useful strategy for therapeutic angiogenesis.

The efficacy and safety of gene transfer into the porcine liver in vivo by HVJ (Sendai virus) liposome

BACKGROUND

Gene transfer systems using viral vectors are efficient; however, most viral vectors also tend to evoke immunologic reactions, thereby clinically causing serial side effects. HVJ-liposome vector is a hybrid vector consisting of liposome and an inactivated Sendai virus (Hemmagglutinating Virus of Japan [HVJ]), which has been reported to be less immunogenic and can also be repeatedly administered. We examined the usefulness of this vector for hepatic gene therapy in a pig model.

METHODS

Genes encoding beta-galactosidase and luciferase were used as reporter genes. The pigs were injected with the reporter gene loaded-HVJ-liposome into the portal vein under total vascular exclusion of the liver. The transfection efficiencies were then assessed by beta-galactosidase staining, a luciferase assay, and RT-PCR for LacZ mRNA. Biochemical and histologic analyses were performed to evaluate tissue toxicity after gene transfer.

RESULTS

The luciferase gene expression in the liver reached its highest level at 7 days after transfection. It continued to be detected up to 28 days after transfection, while all pigs remained healthy throughout the observation period. The transfection efficiency was 15% in the hepatocytes according to beta-galactosidase staining. Extrahepatic transgene expression was slightly observed in the lung and kidney, but not in the spleen or ovary.

CONCLUSIONS

These data suggest for the first time that the use of the HVJ-liposome vector is a safe and feasible modality for liver-directed gene transfer in pigs, and it might therefore be suitable for clinical gene therapy trials.

In vitro gene targeting in human hepatoblastoma

Poor treatment results in advanced hepatoblastoma (HB) made alternative treatment approaches desirable. Gene-directed tumor therapy is increasingly investigated in different malignancies. The aim of this study was to analyze possible alternatives of gene transfer into HB cells and to study therapeutic applications based on different strategies. Liposomal transfection of HB cells was assessed using liver-specific promoters, and adenovirus and Sendai virus transductions were performed in vitro. Transfer efficiencies were measured via flow cytometry determining expression of vector-encoded marker gene green fluorescent protein. Gene silencing of the anti-apoptotic bcl-2 gene in HUH6 cells was performed using lipofection of small interfering RNA (siRNA). Additionally, suicide gene therapy was carried out through a yeast-derived cytosine deaminase (YCD)-combined yeast uracil phosphoribosyltransferase (YUPRT)-based adenovirus-mediated gene transfer, leading to a potent intracellular prodrug transformation of 5-fluorocytosine into 5-fluorouracil. Treatment efficiencies were monitored via MTT viability assay. Highest gene transfer rates (86%) were observed using adenovirus transduction. We furthermore observed a significant therapeutic effect of adenovirus-mediated YCD::YUPRT suicide gene transfer. Liposomal-mediated anti-bcl-2 siRNA transfer led to a significant improvement of cisplatin treatment in HUH6 cells. Liver-specific promoters were found to be strongly active in HUH6 cells (mixed HB-derived), but less active in HepT1 cells (embryonal HB-derived). Liposomal transfection and viral transduction are effective approaches to genetically manipulate HB cells in vitro. For the first time, we demonstrate a positive effect of siRNA gene silencing in this malignancy. Additionally, we successfully investigated a model of adenovirus-based suicide gene therapy in HB cell cultures. Our data strongly encourage further studies assessing these alternative treatment approaches.

Endothelin-mediated increases in lung VEGF content promote vascular leak in young rats exposed to viral infection and hypoxia

Viral respiratory infections increase the susceptibility of young animals to hypoxia-induced pulmonary edema formation. Previous work has shown that increased lung levels of endothelin (ET) contribute to this effect, though the mechanisms by which ET promotes vascular leak remain uncertain. Both in vitro and in vivo evidence suggests that ET can upregulate the production of VEGF, which is known to increase vascular permeability. We hypothesized that increases in lung ET promote increases in lung VEGF, which in turn increases vascular leak in the lung. Weanling rats were exposed to moderate hypoxia for 24 h while recovering from a mild viral respiratory infection, to hypoxia alone, or to viral infection alone. Lung VEGF mRNA and protein content were measured by RT-PCR and Western blotting, respectively. Animals exposed to hypoxia + virus demonstrated significant increases in lung VEGF mRNA and protein content. Immunohistochemical studies showed increased VEGF expression in alveolar septa and small pulmonary vessels in those animals. ET receptor blockade with bosentan prevented this increase in lung VEGF content, suggesting that ET promotes VEGF accumulation in the lung in this setting. Animals exposed to hypoxia + virus also demonstrated substantial increases in lung albumin extravasation, and those increases were blocked by both ET receptor blockade and VEGF antagonism. These findings suggest that ET-driven increases in lung VEGF content can contribute to the formation of pulmonary edema.

Treatment of murine Th1- and Th2-mediated inflammatory bowel disease with NF-kappa B decoy oligonucleotides

The Th1 and Th2 T cell responses that underlie inflammatory bowel diseases (IBDs) are likely to depend on NF-kappaB transcriptional activity. We explored this possibility in studies in which we determined the capacity of NF-kappaB decoy oligodeoxynucleotides (decoy ODNs) to treat various murine models of IBD. In initial studies, we showed that i.r. (intrarectal) or i.p. administration of decoy ODNs encapsulated in a viral envelope prevented and treated a model of acute trinitrobenzene sulfonic acid-induced (TNBS-induced) colitis, as assessed by clinical course and effect on Th1 cytokine production. In further studies, we showed that NF-kappaB decoy ODNs were also an effective treatment of a model of chronic TNBS-colitis, inhibiting both the production of IL-23/IL-17 and the development of fibrosis that characterizes this model. Treatment of TNBS-induced inflammation by i.r. administration of NF-kappaB decoy ODNs did not inhibit NF-kappaB in extraintestinal organs and resulted in CD4+ T cell apoptosis, suggesting that such treatment is highly focused and durable. Finally, we showed that NF-kappaB decoy ODNs also prevented and treated oxazolone-colitis and thus affect a Th2-mediated inflammatory process. In each case, decoy administration led to inflammation-clearing effects, suggesting a therapeutic potency applicable to human IBD.

CCL5-CCR5 interaction provides antiapoptotic signals for macrophage survival during viral infection

Host defense against viruses probably depends on targeted death of infected host cells and then clearance of cellular corpses by macrophages. For this process to be effective, the macrophage must presumably avoid its own virus-induced death. Here we identify one such mechanism. We show that mice lacking the chemokine Ccl5 are immune compromised to the point of delayed viral clearance, excessive airway inflammation and respiratory death after mouse parainfluenza or human influenza virus infection. Virus-inducible levels of Ccl5 are required to prevent apoptosis of virus-infected mouse macrophages in vivo and mouse and human macrophages ex vivo. The protective effect of Ccl5 requires activation of the Ccr5 chemokine receptor and consequent bilateral activation of G(alphai)-PI3K-AKT and G(alphai)-MEK-ERK signaling pathways. The antiapoptotic action of chemokine signaling may therefore allow scavengers to finally stop the host cell-to-cell infectious process.