Enrichment of nucleofected primary human CD4+ T cells: a novel and efficient method for studying gene function and role in human primary T helper cell differentiation

The impact of Nucleofection® on the activation state of primary human CD4 T cells

Gene transfer into primary human CD4 T lymphocytes is a critical tool in studying the mechanism of T cell-dependent immune responses and human immunodeficiency virus-1 (HIV-1) infection. Nucleofection® is an electroporation technique that allows efficient gene transfer into primary human CD4 T cells that are notoriously resistant to traditional electroporation. Despite its popularity in immunological research, careful characterization of its impact on the physiology of CD4 T cells has not been documented. Herein, using freshly-isolated primary human CD4 T cells, we examine the effects of Nucleofection® on CD4 T cell morphology, intracellular calcium levels, cell surface activation markers, and transcriptional activity. We find that immediately after Nucleofection®, CD4 T cells undergo dramatic morphological changes characterized by wrinkled and dilated plasma membranes before recovering 1h later. The intracellular calcium level also increases after Nucleofection®, peaking after 1h before recovering 8h post transfection. Moreover, Nucleofection® leads to increased expression of T cell activation markers, CD154 and CD69, for more than 24h, and enhances the activation effects of phytohemagglutinin (PHA) stimulation. In addition, transcriptional activity is increased in the first 24h after Nucleofection®, even in the absence of exogenous stimuli. Therefore, Nucleofection® significantly alters the activation state of primary human CD4 T cells. The effect of transferred gene products on CD4 T cell function by Nucleofection® should be assessed after sufficient resting time post transfection or analyzed in light of the activation caveats mentioned above.

Efficient delivery of lentiviral vectors into resting human CD4 T cells

Resting human CD4 T cells are highly resistant to transfection or infection with lentiviral vectors derived from the human immunodeficiency virus. We now describe a flexible and efficient approach involving virus-like particles containing simian immunodeficiency virus lentiviral gene product protein X and pseudotyping with CXCR4-tropic HIV Env. This method permits effective genetic manipulation of these cells while preserving their naturally quiescent state. This technology can also be extended to primary lymphoid cultures where authentic cellular composition and functional relationships are preserved.

Early T helper cell programming of gene expression in human

Molecular mechanisms guiding naïve T helper cell differentiation into functionally specified effector cells are intensively studied. The rapidly growing knowledge is mainly achieved by using mouse cells or disease models. Comparatively exiguous data is gathered from human primary cells although they provide the "ultimate model" for immunology in man, have been exploited in many original studies paving the way for the field, and can be analyzed more easily than ever with the help of modern technology and methods. As usage of mouse models is unavoidable in translational research, parallel human and mouse studies should be performed to assure the relevancy of the hypothesis created during the basic research. In this review, we give an overview on the status of the studies conducted with human primary cells aiming at elucidating the mechanisms instructing the priming of T helper cell subtypes. The special emphasis is given to the recent high-throughput studies. In addition, by comparing the human and mouse studies we intend to point out the regulatory mechanisms and questions which are lacking examination with human primary cells.

Advances in siRNA delivery to T-cells: potential clinical applications for inflammatory disease, cancer and infection

The specificity of RNAi and its ability to silence ‘undruggable’ targets has made inhibition of gene expression in T-cells with siRNAs an attractive potential therapeutic strategy for the treatment of inflammatory disease, cancer and infection. However, delivery of siRNAs into primary T-cells represents a major hurdle to their use as potential therapeutic agents. Recent advances in siRNA delivery through the use of electroporation/nucleofection, viral vectors, peptides/proteins, nanoparticles, aptamers and other agents have now enabled efficient gene silencing in primary T-cells both in vitro and in vivo. Overcoming such barriers in siRNA delivery offers exciting new prospects for directly targeting T-cells systemically with siRNAs, or adoptively transferring T-cells back into patients following ex vivo manipulation with siRNAs. In the present review, we outline the challenges in delivering siRNAs into primary T-cells and discuss the mechanism and therapeutic opportunities of each delivery method. We emphasize studies that have exploited RNAi-mediated gene silencing in T-cells for the treatment of inflammatory disease, cancer and infection using mouse models. We also discuss the potential therapeutic benefits of manipulating T-cells using siRNAs for the treatment of human diseases.

Phosphofructokinase deficiency impairs ATP generation, autophagy, and redox balance in rheumatoid arthritis T cells

In the HLA class II-associated autoimmune syndrome rheumatoid arthritis (RA), CD4 T cells are critical drivers of pathogenic immunity. We have explored the metabolic activity of RA T cells and its impact on cellular function and fate. Naive CD4 T cells from RA patients failed to metabolize equal amounts of glucose as age-matched control cells, generated less intracellular ATP, and were apoptosis-susceptible. The defect was attributed to insufficient induction of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a regulatory and rate-limiting glycolytic enzyme known to cause the Warburg effect. Forced overexpression of PFKFB3 in RA T cells restored glycolytic flux and protected cells from excessive apoptosis. Hypoglycolytic RA T cells diverted glucose toward the pentose phosphate pathway, generated more NADPH, and consumed intracellular reactive oxygen species (ROS). PFKFB3 deficiency also constrained the ability of RA T cells to resort to autophagy as an alternative means to provide energy and biosynthetic precursor molecules. PFKFB3 silencing and overexpression identified a novel extraglycolytic role of the enzyme in autophagy regulation. In essence, T cells in RA patients, even those in a naive state, are metabolically reprogrammed with insufficient up-regulation of the glycolytic activator PFKFB3, rendering them energy-deprived, ROS- and autophagy-deficient, apoptosis-sensitive, and prone to undergo senescence.

Proviral integration site for Moloney murine leukemia virus (PIM) kinases promote human T helper 1 cell differentiation

The differentiation of human primary T helper 1 (Th1) cells from naïve precursor cells is regulated by a complex, interrelated signaling network. The identification of factors regulating the early steps of Th1 cell polarization can provide important insight in the development of therapeutics for many inflammatory and autoimmune diseases. The serine/threonine-specific proviral integration site for Moloney murine leukemia virus (PIM) kinases PIM1 and PIM2 have been implicated in the cytokine-dependent proliferation and survival of lymphocytes. We have established that the third member of this family, PIM3, is also expressed in human primary Th cells and identified a new function for the entire PIM kinase family in T lymphocytes. Although PIM kinases are expressed more in Th1 than Th2 cells, we demonstrate here that these kinases positively influence Th1 cell differentiation. Our RNA interference results from human primary Th cells also suggest that PIM kinases promote the production of IFNγ, the hallmark cytokine produced by Th1 cells. Consistent with this, they also seem to be important for the up-regulation of the critical Th1-driving factor, T box expressed in T cells (T-BET), and the IL-12/STAT4 signaling pathway during the early Th1 differentiation process. In summary, we have identified PIM kinases as new regulators of human primary Th1 cell differentiation, thus providing new insights into the mechanisms controlling the selective development of human Th cell subsets.

Novel strategy for microsphere-mediated DNA transfection

A new approach for microsphere-mediated delivery of plasmid DNA has been developed and successfully evaluated. Basic molecular biology techniques were used to linearize and functionalize plasmid DNA by aminomodification, enabling efficient conjugation to carboxy-functionalized microspheres. A T cell hybridoma line was successfully transfected as determined by the efficient expression of a biologically relevant YFP fusion protein. Moreover, our data identified microsphere-mediated delivery of plasmid DNA as a noninvasive, nontoxic, and efficient gene delivery method with the potential to be applied to transfection-resistant, nondividing primary cells, including naïve T cells.

Contributions of gene marking to cell and gene therapies

The first human genetic modification studies used replication-incompetent integrating vector vectors to introduce marker genes into T lymphocytes and subsequently into hematopoietic stem cells. Such studies have provided numerous insights into the biology of hematopoiesis and immune reconstitution and contributed to clinical development of gene and cell therapies. Tracking of hematopoietic reconstitution and analysis of the origin of residual malignant disease after hematopoietic transplantation has been possible via gene marking. Introduction of selectable marker genes has enabled preselection of specific T-cell populations for tumor and viral immunotherapy and reduced the threat of graft-versus-host disease, improving the survival of patients after allogeneic marrow transplantation. Marking studies in humans, murine xenografts, and large animals have helped optimize conditions for gene transfer into CD34(+) hematopoietic progenitors, contributing to the achievement of gene transfer efficiencies sufficient for clinical benefit in several serious genetic diseases such as X-linked severe combined immunodeficiency and adrenoleukodystrophy. When adverse events linked to insertional mutagenesis arose in clinical gene therapy trials for inherited immunodeficiencies, additional animal studies using gene-marking vectors have greatly increased our understanding of genotoxicity. The knowledge gained from these studies is being translated into new vector designs and clinical protocols, which we hope will continue to improve the efficiency, effectiveness and safety of these promising therapeutic approaches.

Mesenchymal stem cells overexpressing ephrin-b2 rapidly adopt an early endothelial phenotype with simultaneous reduction of osteogenic potential

Restoration of the vascular supply to ischemic tissues is of high clinical relevance, and proangiogenic therapies aim to reduce morbidity and mortality rates associated with the onset of cardiovascular disease. Stem cell therapy has been proposed as a potentially useful proangiogenic therapy. Mesenchymal stem cells (MSCs) have been shown to be proangiogenic and produce a number of cytokines involved in vessel development and maturation. Preclinical studies have reported increased angiogenesis after MSC delivery to the heart, and similar outcomes have been reported in recent clinical trials. Stem-cell-mediated neovascularization has been augmented by genetic modification with overexpression of angiogenic cytokines, including vascular endothelial growth factor (VEGF) and platelet-derived growth factor, showing promising results. In this study we aimed to enhance the proangiogenic capability of MSCs. MSCs were genetically modified to overexpress a versatile molecule, Ephrin-B2, involved in tissue morphogenesis and vascular development to enhance inherent neovascularization potential. Using nucleofection, Ephrin-B2 was transiently overexpressed on the cell surface of MSCs to recapitulate embryonic signaling and promote neovascularization. Ephrin-B2-expressing MSCs adopted an early endothelial phenotype under endothelial cell culture conditions increasing expression of von Willebrand factor and VEGF-Receptor 2. The cells had an increased ability to form vessel-like structures, produce VEGF, and incorporate into newly formed endothelial cell structures. These data indicate that MSCs expressing Ephrin-B2 represent a novel proangiogenic cell source to promote neovascularization in ischemic tissues.

Inhibition of type 1 diabetes by upregulation of the circadian rhythm-related aryl hydrocarbon receptor nuclear translocator-like 2

The genetic locus Idd6 is involved in type 1 diabetes development in the non-obese diabetic (NOD) mouse through its effect on the immune system and in particular, on T cell activities. Analysis of congenic strains for Idd6 has established the Aryl hydrocarbon receptor nuclear translocator-like 2 (Arntl2) as a likely candidate gene. In this study we investigate the role of Arntl2 in the autoimmune disease and T cell activation. An Arntl2 expressing plasmid was transfected into CD4(+) T cells by nucleofection. Expression levels of cytokines and CD4(+) T cell activation markers, cell death, apoptosis, and cell proliferation rates were characterized in ex vivo experiments whilst in vivo the transfected cells were transferred into NOD.SCID mice to monitor diabetes development. The results demonstrate that Arntl2 overexpression leads to inhibition of CD4(+) T cell proliferation and decreases in their diabetogenic activity without influence on the expression levels of cytokines, CD4(+) T cell activation markers, cell death, and apoptosis. Our findings suggest that Arntl2 at the Idd6 locus may act via the inhibition of CD4(+) T cell proliferation and the reduction in the diabetogenic activity of CD4(+) T cells to protect against autoimmune type 1 diabetes in the NOD mice.

SATB1 dictates expression of multiple genes including IL-5 involved in human T helper cell differentiation

Special AT-rich binding protein 1 (SATB1) is a global chromatin organizer and a transcription factor regulated by interleukin-4 (IL-4) during the early T helper 2 (Th2) cell differentiation. Here we show that SATB1 controls multiple IL-4 target genes involved in human Th cell polarization or function. Among the genes regulated by SATB1 is that encoding the cytokine IL-5, which is predominantly produced by Th2 cells and plays a key role in the development of eosinophilia in asthma. We demonstrate that, during the early Th2 cell differentiation, IL-5 expression is repressed through direct binding of SATB1 to the IL-5 promoter. Furthermore, SATB1 knockdown-induced up-regulation of IL-5 is partly counteracted by down-regulating GATA3 expression using RNAi in polarizing Th2 cells. Our results suggest that a competitive mechanism involving SATB1 and GATA3 regulates IL-5 transcription, and provide new mechanistic insights into the stringent regulation of IL-5 expression during human Th2 cell differentiation.

Quantitative proteomics analysis of the nuclear fraction of human CD4+ cells in the early phases of IL-4-induced Th2 differentiation

We used stable isotope labeling with 4-plex iTRAQ (isobaric tags for relative and absolute quantification) reagents and LC-MS/MS to investigate proteomic changes in the nucleus of activated human CD4⁺ cells during the early stages of Th2 cell differentiation. The effects of IL-4 stimulation upon activated naïve CD4⁺ cells were measured in the nuclear fractions from 6 and 24 h in three biological replicates, each using pooled cord blood samples derived from seven or more individuals. In these analyses, in the order of 800 proteins were detected with two or more peptides and quantified in three biological replicates. In addition to consistent differences observed with the nuclear localization/expression of established human Th2 and Th1 markers, there were changes that suggested the involvement of several proteins either only recently reported or otherwise not known in this context. These included SATB1 and among the novel changes detected and validated an IL-4-induced increase in the level of YB1. This unique data set from human cord blood CD4⁺ T cells details an extensive list of protein determinations that compares with and complements previous data determined from the Jurkat cell nucleus.

Activating transcription factor 3 is a positive regulator of human IFNG gene expression

IL-12 and IL-18 are essential for Th1 differentiation, whereas the role of IFN-alpha in Th1 development is less understood. In this microarray-based study, we searched for genes that are regulated by IFN-alpha, IL-12, or the combination of IL-12 plus IL-18 during the early differentiation of human umbilical cord blood CD4(+) Th cells. Twenty-six genes were similarly regulated in response to treatment with IL-12, IFN-alpha, or the combination of IL-12 plus IL-18. These genes could therefore play a role in Th1 lineage decision. Transcription factor activating transcription factor (ATF) 3 was upregulated by these cytokines and selected for further study. Ectopic expression of ATF3 in CD4(+) T cells enhanced the production of IFN-gamma, the hallmark cytokine of Th1 cells, whereas small interfering RNA knockdown of ATF3 reduced IFN-gamma production. Furthermore, ATF3 formed an endogenous complex with JUN in CD4(+) T cells induced to Th1. Chromatin immunoprecipitation and luciferase reporter assays showed that both ATF3 and JUN are recruited to and transactivate the IFNG promoter during early Th1 differentiation. Collectively, these data indicate that ATF3 promotes human Th1 differentiation.

RTKN2 Induces NF-KappaB Dependent Resistance to Intrinsic Apoptosis in HEK Cells and Regulates BCL-2 Genes in Human CD4(+) Lymphocytes

The gene for Rhotekin 2 (RTKN2) was originally identified in a promyelocytic cell line resistant to oxysterol-induced apoptosis. It is differentially expressed in freshly isolated CD4⁺ T-cells compared with other hematopoietic cells and is down-regulated following activation of the T-cell receptor. However, very little is known about the function of RTKN2 other than its homology to Rho-GTPase effector, rhotekin, and the possibility that they may have similar roles. Here we show that stable expression of RTKN2 in HEK cells enhanced survival in response to intrinsic apoptotic agents; 25-hydroxy cholesterol and camptothecin, but not the extrinsic agent, TNFα. Inhibitors of NF-KappaB, but not MAPK, reversed the resistance and mitochondrial pro-apoptotic genes, Bax and Bim, were down regulated. In these cells, there was no evidence of RTKN2 binding to the GTPases, RhoA or Rac2. Consistent with the role of RTKN2 in HEK over-expressing cells, suppression of RTKN2 in primary human CD4⁺ T-cells reduced viability and increased sensitivity to 25-OHC. The expression of the pro-apoptotic genes, Bax and Bim were increased while BCL-2 was decreased. In both cell models RTKN2 played a role in the process of intrinsic apoptosis and this was dependent on either NF-KappaB signaling or expression of downstream BCL-2 genes. As RTKN2 is a highly expressed in CD4⁺ T-cells it may play a role as a key signaling switch for regulation of genes involved in T-cell survival.

PRELI is a mitochondrial regulator of human primary T-helper cell apoptosis, STAT6, and Th2-cell differentiation

The identification of novel factors regulating human T helper (Th)-cell differentiation into functionally distinct Th1 and Th2 subsets is important for understanding the mechanisms behind human autoimmune and allergic diseases. We have identified a protein of relevant evolutionary and lymphoid interest (PRELI), a novel protein that induces oxidative stress and a mitochondrial apoptosis pathway in human primary Th cells. We also demonstrated that PRELI inhibits Th2-cell development and down-regulates signal transducer and activator of transcription 6 (STAT6), a key transcription factor driving Th2 differentiation. Our data suggest that calpain, an oxidative stress-induced cysteine protease, is involved in the PRELI-induced down-regulation of STAT6. Moreover, we observed that a strong T-cell receptor (TCR) stimulus induces expression of PRELI and inhibits Th2 development. Our results suggest that PRELI is involved in a mechanism wherein the strength of the TCR stimulus influences the polarization of Th cells. This study identifies PRELI as a novel factor influencing the human primary Th-cell death and differentiation.

Quantitative proteomics reveals GIMAP family proteins 1 and 4 to be differentially regulated during human T helper cell differentiation

T helper (Th) cells differentiate into functionally distinct effector cell subsets of which Th1 and Th2 cells are best characterized. Besides T cell receptor signaling, IL-12-induced STAT4 and T-bet- and IL-4-induced STAT6 and GATA3 signaling pathways are the major players regulating the Th1 and Th2 differentiation process, respectively. However, there are likely to be other yet unknown factors or pathways involved. In this study we used quantitative proteomics exploiting cleavable ICAT labeling and LC-MS/MS to identify IL-4-regulated proteins from the microsomal fractions of CD4(+) cells extracted from umbilical cord blood. We were able to identify 557 proteins of which 304 were also quantified. This study resulted in the identification of the down-regulation of small GTPases GIMAP1 and GIMAP4 by IL-4 during Th2 differentiation. We also showed that both GIMAP1 and GIMAP4 genes are up-regulated by IL-12 and other Th1 differentiation-inducing cytokines in cells induced to differentiate toward Th1 lineage and down-regulated by IL-4 in cells induced to Th2. Our results indicate that the GIMAP (GTPase of the immunity-associated protein) family of proteins is differentially regulated during Th cell differentiation.

PILAR is a novel modulator of human T-cell expansion

Robust T-cell responses without autoimmunity are only possible through a fine balance between activating and inhibitory signals. We have identified a novel modulator of T-cell expansion named proliferation-induced lymphocyte-associated receptor (PILAR). Surface PILAR is markedly up-regulated on CD4 and, to a lesser extent, on CD8 T cells on T-cell receptor engagement. In absence of CD28 costimulation, PILAR signaling through CD161 supports CD3 antibody-dependent and antigen-specificT-cell proliferation by increasing the expression of antiapoptotic Bcl-xL and induces secretion of T helper type 1 cytokines. These effects are abrogated by PILAR blockade with specific antibodies, which decrease surface levels of CD28. In contrast, PILAR induces apoptotic death on naive and early activated T cells if CD161 engagement is blocked. PILAR is expressed by approximately 7% to 10% of CD4 T cells in 2 samples of inflammatory synovial fluid, suggesting a potential role in the pathogenesis of joint inflammation. In addition, in the ovarian cancer microenvironment, effector T cells express PILAR, but not CD161, although expression of both can be augmented ex vivo. Our results indicate that PILAR plays a central role in modulating the extent of T-cell expansion. Manipulation of PILAR signaling may be important for treatment of autoimmune diseases and cancer.

Functional characterization of the atopy-associated gene PHF11

BACKGROUND

Polymorphisms in the plant homeodomain finger protein 11 gene (PHF11) are associated with increased total serum IgE levels, asthma, and severe atopic dermatitis (AD) in children. Although PHF11 includes a plant homeodomain, a motif often found in transcriptional regulators, the function of PHF11 has not been investigated.

OBJECTIVE

We sought to test (1) whether PHF11 regulates the transcription of genes involved in allergic disorders and (2) whether polymorphisms in PHF11 predict changes in the expression or function of this gene.

METHODS

Microarray analysis was used to examine the expression of PHF11 in different immune cell subsets, and the function of PHF11 was tested by using small interfering RNA-induced knockdown or overexpression of PHF11 in primary CD4+ T cells or Jurkat T cells. Genotype-dependent effects on PHF11 expression were tested by using an allele-specific gene expression, and the transcriptional activity of PHF11 was determined by using luciferase hybrid gene reporter assays and in vitro DNA-binding electromobility shift assays.

RESULTS

PHF11 expression was higher in T(H)1 cells relative to that in T(H)2 cells, and knockdown of PHF11 expression reduced expression of the T(H)1-type cytokines IFN-gamma and IL-2. The G-allele of a 3' untranslated region polymorphism associated with AD was correlated with reduced abundance of PHF11 RNA in T(H)1 cells, as well as an increase in a PHF11 isoform lacking exon II. Evidence was also found for a physical and functional interaction between PHF11 and the p65 subunit of nuclear factor kappaB.

CONCLUSION

PHF11 is a regulator of T(H)1-type cytokine gene expression. The reduction in PHF11 expression seen with an AD-associated genotype could contribute to the strong T(H)2 responses that characterize many allergic individuals.

An insight into molecular mechanisms of human T helper cell differentiation

Selective activation of T helper (Th) cell subsets plays an important role in immune response to pathogens as well as in the pathogenesis of human allergy and inflammatory diseases. Th1 cells along with the recently discovered Th17 cells play a role in the pathogenesis of autoimmune diseases. Th2 cytokines lead to series of inflammatory processes characteristic for asthma and other atopic diseases. To understand the pathogenesis of immune-mediated diseases it is crucial to dissect pathways and regulatory networks leading to the development of distinct Th subsets. Such knowledge may lead to better strategies for developing diagnostics and therapies for these diseases. The differentiation of Th1, Th2, and Th17 effector cells is driven by signals originating from T cell and costimulatory receptors as well as cytokines in the surroundings of activated naive T helper cells. There are several proteins involved in the regulation of this differentiation process. Most of the data on T helper cell differentiation have been acquired using mouse. In this review, we have summarized what is known about human T helper differentiation. In addition, selected differences between human and mouse will be discussed.

Genome-wide identification of novel genes involved in early Th1 and Th2 cell differentiation

Th cell subtypes, Th1 and Th2, are involved in the pathogenesis or progression of many immune-mediated diseases, such as type 1 diabetes and asthma, respectively. Defining the molecular networks and factors that direct Th1 and Th2 cell differentiation will help to understand the pathogenic mechanisms causing these diseases. Some of the key factors regulating this differentiation have been identified, however, they alone do not explain the process in detail. To identify novel factors directing the early differentiation, we have studied the transcriptomes of human Th1 and Th2 cells after 2, 6, and 48 h of polarization at the genome scale. Based on our current and previous studies, 288 genes or expressed sequence tags, representing approximately 1-1.5% of the human genome, are regulated in the process during the first 2 days. These transcriptional profiles revealed genes coding for components of certain pathways, such as RAS oncogene family and G protein-coupled receptor signaling, to be differentially regulated during the early Th1 and Th2 cell differentiation. Importantly, numerous novel genes with unknown functions were identified. By using short-hairpin RNA knockdown, we show that a subset of these genes is regulated by IL-4 through STAT6 signaling. Furthermore, we demonstrate that one of the IL-4 regulated genes, NDFIP2, promotes IFN-gamma production by the polarized human Th1 lymphocytes. Among the novel genes identified, there may be many factors that play a crucial role in the regulation of the differentiation process together with the previously known factors and are potential targets for developing therapeutics to modulate Th1 and Th2 responses.

A preliminary study towards downregulation of murine bone marrow eosinophilopoiesis mediated by small molecule inhibition of interleukin-5 receptor alpha gene in vitro

BACKGROUND

Bone marrow eosinophilopoiesis induced by IL-5 makes a major contribution to eosinophilic airway inflammation in asthma. Bone marrow CD(34)(+) cells expressing IL-5Ralpha may be eosinophil progenitors. However, research on the effect of blocking IL-5Ralpha expression on bone marrow eosinophilopoiesis has seldom been reported.

OBJECTIVE

To explore the effect of inhibiting IL-5Ralpha expression with IL-5Ralpha short hairpin RNA-expressing vector on murine bone marrow eosinophilopoiesisin vitro.

METHODS

We constructed 4 kinds of plasmid vectors that could express small molecule inhibition, short hairpin RNA, which targeted IL-5Ralpha (P-IL-5Ralpha), and selected an effective one by transfecting B lymphoma cells in vitro. We also constructed an adenovirus vector which was inserted into an effective template sequence (Ad-IL-5Ralpha). The bone marrow cells were obtained from healthy Balb/c mice, and cultured and transfected by Ad-IL-5Ralpha in vitro. The expression of IL-5Ralpha and the count of newly produced eosinophils were detected in the cultured bone marrow cells.

RESULTS

We found that P-IL-5Ralpha-3 targeted at the sequence of CAG CTG CCT GGT TCG TCT T markedly suppressed the IL-5Ralpha expression in the B lymphoma cellsin vitro. Ad-IL-5Ralpha could suppress the IL-5Ralpha expression of murine bone marrow cellsin vitro and it could also significantly decrease the IL-5-induced eosinophilia in the cultured bone marrow cells.

CONCLUSION

These results indicate that the blocking of IL-5Ralpha expression by small molecule inhibition can help to effectively decrease murine bone marrow eosinophilopoiesis, and that bone marrow may be used as a critical target organ in the diseases involved in eosinophilia, such as asthma.

Effect of interleukin-5 receptor-alpha short hairpin RNA-expressing vector on bone marrow eosinophilopoiesis in asthmatic mice

Bone marrow eosinophilopoiesis induced by interleukin (IL)-5 is a major contributor to eosinophilic airway inflammation in asthma. However,research on the use of IL-5 receptor alpha (IL-5Ralpha) as the target has seldom been reported. This study was undertaken to explore the effects of inhibition of IL-5Ralpha expression through an IL-5Ralpha short hairpin RNA-expressing vector on bone marrow eosinophilopoiesis and airway inflammation in an asthmatic mouse model. An effective plasmid vector was selected that could express short hairpin RNA targeted at IL-5Ralpha (P-IL-5Ralpha). An adenovirus vector (Ad) was then constructed that was inserted in an effective template sequence (Ad-IL-5Ralpha). An animal model of asthma was established by sensitizing and challenging Balb/c mice with ovalbumin. Animals were treated intravenously with Ad-IL-5Ra and changes in bone marrow eosinophilopoiesis and airway inflammation were detected in asthmatic mice. Investigators found that P-IL-5Ra-3 targeted at the sequence of CAG CTG CCT GGT TCG TCT T markedly suppressed IL-5Ralpha expression in B lymphoma cells in vitro. In addition, Ad-IL-5Ralpha could suppress IL-5Ralpha expression in murine bone marrow cells in vitro and in vivo, and it could significantly decrease IL-5-induced eosinophilia in cultured bone marrow cells. Additional studies indicated that intravenously injected Ad-IL-5Ralpha not only selectively reduced the number of eosinophils in the bone marrow, peripheral blood, and bronchoalveolar lavage fluid, it also relieved airway inflammation in asthmatic mice. Results reported here show that blocking of IL-5Ralpha expression through RNA interference can enhance effective treatment of asthma, and that bone marrow can be used as a key targeted organ in the treatment of asthmatic mice.