Novel vaccination for allergy through gene silencing of CD40 using small interfering RNA

The Role of CD40 in Allergic Rhinitis and Airway Remodelling

Background

Allergic rhinitis (AR) affects millions of people and is lack of effective treatment. CD40 is an important costimulatory molecule in immunity. However, few studies have focused on the role of CD40 in AR.

Methods

In this study, we built mouse model of chronic AR. The mice were divided into the AR, control, intravenous CD40 siRNA, and nasal CD40 siRNA groups (n = 6 each). We detected OVA-sIgE, IL-4, IL-5, IL-13, IL-10, IFN-γ, and TGF-β levels in serum and supernatant by ELISA, CD40⁺ splenic DCs, and Foxp3⁺ Tregs by flow cytometry and CD40 mRNA by RT²-PCR. We also used PAS and MT stains to assess tissue remodelling.

Results

(1) The OVA-sIgE, IL-4, IL-5, and IL-13 levels in the serum or supernatant of nasal septal membrane of AR mice were significantly higher than control. After treated with CD40 siRNA, those indicators were significantly decreased. The IFN-γ, IL-10, and TGF-β levels in AR mice were significantly lower than that in control and were increased by administration of CD40 siRNA. (2) AR mice had significantly fewer Foxp3⁺ Tregs in the spleen than control mice. After treated with CD40 siRNA, AR mice had significantly more Foxp3⁺ Tregs. (3) AR mice exhibited a significantly higher CD40 mRNA levels than control. Administration of CD40 siRNA significantly reduced the CD40 mRNA level. (4) The AR mice showed significantly greater collagen deposition than the control in MT staining. Applications of CD40 siRNA significantly reduced the collagen deposition in AR mice.

Conclusion

CD40 siRNA therapy shows promise for chronic AR as it significantly attenuated allergic symptoms and Th2-related inflammation and upregulated Foxp3⁺ Tregs. CD40 plays a role in tissue remodelling in AR, which can be inhibited by CD40 siRNA application.

CD40 signaling augments IL-10 expression and the tolerogenicity of IL-10-induced regulatory dendritic cells

CD40 expressed on stimulatory dendritic cells (DC) provides an important accessory signal for induction of effector T cell responses. It is also expressed at lower levels on regulatory DC (DCreg), but there is little evidence that CD40 signaling contributes to the tolerogenic activity of these cells. Indeed, CD40 silencing within DCreg has been reported to induce T cell tolerance in multiple disease models, suggesting that CD40 is superfluous to DC-induced tolerance. We critically assessed whether CD40 does have a role in tolerance induced by IL-10-differentiated DC (DC10) by using DC10 generating from the bone marrow of wild-type (w.t.) or CD40^-/- donor mice, or IL-10-complemented CD40^-/- DC10 to treat asthmatic mice. Wild-type DC10 ablated the OVA-asthma phenotype via induction of Foxp3⁺ Treg responses, but CD40^-/- DC10 had no discernible effects on primary facets of the phenotype (e.g., IL-5, IL-9, IL-13 levels, IgE & IgG1 antibodies; p>0.05) and were ≤40% effective in reversal of others. Foxp3⁺ T cells from the lungs of CD40^-/- DC10-treated mice expressed reduced levels of a panel of six Treg-specific activation markers relative to Treg from w.t. DC10-treated mice. Coculture with effector T cells from asthmatic mice induced a marked upregulation of cell surface CD40 on w.t. DC10. While untreated CD40^-/- and w.t. DC10 secreted equally low levels of IL-10, stimulation of w.t. DC10 with anti-CD40 for 72 h increased their expression of IL-10 by ≈250%, with no parallel induction of IL-12. Complementing IL-10 expression in CD40^-/- DC10 by IL-10 mRNA transfection fully restored the cells’ abilities to suppress the asthma phenotype. In summary, CD40 signaling in DC10 contributes importantly to their expression of IL-10 and to a robust induction of tolerance, including activation of induced Treg.

Intranasal administration of regulatory dendritic cells is useful for the induction of nasal mucosal tolerance in a mice model of allergic rhinitis

Background

Intranasally administered dendritic cells (DCs) migrate into blood and thymus to induce immune responses. Regulatory dendritic cells (DCs) are also useful agents for allergy control. However, to the best of our knowledge, the effects of intranasal administration of regulatory DCs on allergy have not been reported until now. Therefore, we examined the effects of intranasal route of administration of CD40-silenced DCs on allergic responses and compared these with the effects of other administration routes, based on our previous findings on the inhibitory effects of CD40-silenced DCs on allergic responses.

Methods

Mice with allergic rhinitis were treated intranasally, subcutaneously, intraperitoneally, or intravenously with CD40-silenced ovalbumin (OVA)-pulsed DCs that were transfected with CD40 siRNAs and pulsed with OVA antigen. The effects of these DCs on allergic reactions and symptoms were estimated.

Results

Intranasal, subcutaneous, intraperitoneal, or intravenous administration of OVA-pulsed CD40-silenced DCs inhibited allergic responses and symptoms in mice. Furthermore, intranasal administration of OVA-pulsed CD40-silenced DCs significantly reduced allergic symptoms and the number of eosinophils in the nasal mucosa compared with subcutaneous, intraperitoneal, or intravenous administration of these DCs. Intranasal administration of OVA-pulsed CD40-silenced DCs resulted in significantly up-regulated IL-10, IL-35, and Foxp3 expression, and enhanced the percentage of CD11c⁺CD40⁻ and CD4⁺CD25⁺ cells within the cervical lymph nodes compared to subcutaneous, intraperitoneal, or intravenous routes of administration.

Conclusions

We believe that this is the first report to demonstrate that regulatory DCs infiltrate into the cervical lymph nodes after intranasal administration of these cells and that intranasal administration of regulatory DCs is more effective for the induction of tolerance in the nasal mucosa than subcutaneous, intraperitoneal, or intravenous administration.

Ribonucleic Acid Engineering of Dendritic Cells for Therapeutic Vaccination: Ready 'N Able to Improve Clinical Outcome?

Targeting and exploiting the immune system has become a valid alternative to conventional options for treating cancer and infectious disease. Dendritic cells (DCs) take a central place given their role as key orchestrators of immunity. Therapeutic vaccination with autologous DCs aims to stimulate the patient's own immune system to specifically target his/her disease and has proven to be an effective form of immunotherapy with very little toxicity. A great amount of research in this field has concentrated on engineering these DCs through ribonucleic acid (RNA) to improve vaccine efficacy and thereby the historically low response rates. We reviewed in depth the 52 clinical trials that have been published on RNA-engineered DC vaccination, spanning from 2001 to date and reporting on 696 different vaccinated patients. While ambiguity prevents reliable quantification of effects, these trials do provide evidence that RNA-modified DC vaccination can induce objective clinical responses and survival benefit in cancer patients through stimulation of anti-cancer immunity, without significant toxicity. Succinct background knowledge of RNA engineering strategies and concise conclusions from available clinical and recent preclinical evidence will help guide future research in the larger domain of DC immunotherapy.

Distraction of olfactory bulb-medial prefrontal cortex circuit may induce anxiety-like behavior in allergic rhinitis

Allergic rhinitis is a chronic inflammatory disease of the upper respiratory tract, which is associated with high incidence of anxiety symptom. There is evidence that medial prefrontal cortex modulates anxiety-related behaviors and receives projections from olfactory bulb. Since olfactory dysfunction has been reported in allergic rhinitis, we aimed to evaluate anxiety-like behavior and oscillations of olfactory bulb-medial prefrontal cortex circuit in an animal model of allergic rhinitis. The number of open arm entries in elevated zero maze was significantly reduced in sensitized rats exposed to intranasal ovalbumin compared to the control group, which was indicating the enhancement of anxiety-like behavior in allergic rhinitis animals. Analysis of local field potentials in olfactory bulb and medial prefrontal cortex during immobility and exploration state showed that anxiety-like behavior induced by allergic rhinitis was in association with increased activity of medial prefrontal cortex and enhancement of olfactory bulb-medial prefrontal cortex coupling in delta and theta bands. Moreover, in allergic rhinitis animals, theta strongly coordinates local gamma activity in olfactory bulb and medial prefrontal cortex, which means to have a strong local theta/gamma coupling. We suggested that disruption of olfactory bulb-medial prefrontal cortex circuit due to allergic reactions might have a governing role for inducing anxiety-like behavior in the allergic rhinitis experimental model.

Impacts of CD40- and CD86-Silenced Antigen-Specific B Cells on the Control of Allergies

Background

We previously reported that CD40-silenced B cells inhibited allergic responses and symptoms. However, more potent therapies are needed. To our knowledge, the effects of CD86-silenced B cells and synergic effects of gene silencing in B cells by 2 small interfering RNAs (siRNAs) on allergic disease control have not been reported.

Objective

To investigate the effects of CD86-silenced B cells and synergic effects of gene silencing in B cells on allergic responses and symptoms.

Methods

Mice were treated with CD40- and/or CD86-silenced B cells transfected with siRNAs and pulsed with ovalbumin (OVA). And the effects of these B cells were estimated.

Results

CD86-silenced OVA-pulsed B cells significantly inhibited OVA-induced allergies. Treatment with CD40-/CD86-silenced OVA-pulsed B cells led to a significantly fewer sneezes and nasal rubbing movements, as well as lower OVA-specific immunoglobulin E (IgE) levels, than that with CD40-silenced or CD86-silenced OVA-pulsed B cells alone. These inhibitory effects were observed prior to sensitization as well as after the establishment of allergic rhinitis. CD40-/CD86-silenced OVA-pulsed B cells did not inhibit keyhole limpet hemocyanin-induced allergies. CD40-/CD86-silenced OVA-pulsed B cells also significantly inhibited allergic symptoms and OVA-specific IgE level in sera compared with CD40-/CD86-silenced OVA-pulsed dendritic cells (DCs). In addition, CD19+CD40− B cells significantly increased in the nasal tissue after intravenous administration of these cells. Furthermore, CD40-/CD86-silenced B cells inhibited allergic symptoms caused by Cry j 1, a major aeroallergen of Japanese cedar pollen, and Cry j 1-specific IgE in sera.

Conclusion

This study showed, for the first time, that siRNA-induced CD86-silenced B cells significantly inhibited allergic responses and symptoms antigen-specifically, and that siRNA-induced CD40-/CD86-silenced antigen-specific B cells are a more useful antigen-specific therapy than CD40- or CD86-silenced B cells alone for the control of allergies. Furthermore, it was shown that CD40-/CD86-silenced B cells have stronger inhibition of IgE production and allergic symptoms than CD40-/CD86-silenced DCs.

Sleep Disturbance and Hyperactivity Detected by Actigraphy in Rats with Allergic Rhinitis or Attention-Deficit Hyperactivity Disorder

Actigraphy is an easy and noninvasive method used to monitor human ultradian cycles. However, to our knowledge, it has been not applied to experiments with rodents. Therefore, using actigraphy, we assessed the ultradian cycles and behavior of rats. Rats with or without allergic rhinitis wore an actigraphy device, and triaxial acceleration was recorded. The counts that represent physical activity were lower from 8:00 to 20:00 than those from 20:00 to 8:00 in control rats, suggesting that their sleep phase was from 8:00 to 20:00 and their awake phase from 20:00 to 8:00. The counts from 8:00 to 10:00 were significantly higher in allergic rhinitis rats than in control rats (p < 0.01), suggesting the presence of difficulty with sleep induction in rats with allergic rhinitis. The counts from 18:00 to 20:00 were also significantly higher in allergic rhinitis rats than in control rats (p < 0.05), suggesting the presence of early awakening in rats with allergic rhinitis. Moreover, the counts were significantly higher in allergic rhinitis rats than in control rats from 20:00 to 8:00. These results suggest that rats with allergic rhinitis experienced hyperactivity disorder during the daytime. Additionally, hyperreactivity and difficulty with sleep induction were observed in 6-hydroxydopamine-lesioned rats, an animal model of attention-deficit hyperactivity disorder. This study shows for the first time that actigraphy can be successfully used for behavioral analysis in rodents. These rat models could be useful for analyzing the mechanisms involved in sleep disturbances and hyperactivity disorder.

Intranasal Administration of IL-27 Ameliorates Nasal Allergic Responses and Symptoms

BACKGROUND

Interleukin 27 (IL-27) is an initiator of the Th1 response and inhibits inflammatory responses. In a mouse model of asthma, administration of IL-27 reduced eosinophil numbers in bronchoalveolar lavage fluid and airway hyperresponsiveness. However, it is unclear whether administration of IL-27 can inhibit symptoms of allergic diseases and allergic rhinitis as a therapeutic agent. Therefore, we investigated the in vivo effect of IL-27 on nasal symptoms and allergic rhinitis.

METHODS

Mice sensitized and challenged with ovalbumin (OVA) antigen received intranasal administration of IL-27.

RESULTS

Intranasal administration of IL-27 significantly suppressed the number of sneezes and nasal rubbing movements, the number of eosinophils, OVA-specific T-cell responses in cervical lymph nodes, production of IL-4 and IL-5, and OVA-specific IgE in sera, compared with the administration of PBS alone. The production of IL-10 and IL-35, the percentage of CD25+Foxp3+ cells, and the gene expression of Foxp3 in mice that received intranasal administration of IL-27 were also significantly higher than those in mice that received only PBS.

CONCLUSIONS

This study showed, for the first time, that intranasal administration of IL-27 inhibited nasal allergic responses and symptoms even after the establishment of allergic rhinitis and suggested that IL-27 is useful as an intranasal therapeutic agent.

RNAi targeting Nogo Receptor enhanced survival and proliferation of murine retinal ganglion cells during N-methyl-D-aspartate-induced optic nerve crush

We investigated the effects of lentivirus-mediated RNAi targeting of Nogo Receptor (NgR) on the proliferation and survival of murine retinal ganglion cells (mRGCs) in vitro and in vivo. Cultured mRGCs and C57BL/6 male mice were divided into 4 experimental groups: blank, model [100 μM N-methyl-D-aspartate (NMDA)], nscRNA (100 μM NMDA+ nscRNA vectors) and siNgR (100 μM NMDA+ siNgR vectors). CCK-8 and flow cytometry analyses revealed that silencing NgR enhanced proliferation, cell cycling and survival of NMDA-treated mRGCs. H&E staining showed that NgR silencing enhanced mRGC cell density and reduced angiogenesis in NMDA-treated retinal tissues. TUNEL assays showed that mRGC apoptosis was significantly diminished by NgR silencing in NMDA-treated retinal tissues. Western blotting and qRT-PCR analysis in NMDA-treated mRGCs and murine retinal tissues revealed that NgR silencing resulted in downregulation of RhoA signaling (RhoA and ROCK2). Western blotting showed that levels of activated Bax and cleaved caspase 3 were decreased, while Bcl-2 and pro-caspase 3 were increased in NMDA-treated mRGCs and murine retinal tissues, which corroborated the decreased apoptosis. These findings indicate that NgR gene silencing increases proliferation and survival of mRGCs in NMDA-treated murine retinas, which suggests a potential for therapeutic application to preventing optic nerve damage.

Intranasal administration of IL-35 inhibits allergic responses and symptoms in mice with allergic rhinitis

Background

IL-35 was recently identified as an anti-inflammatory cytokine. We previously reported that recombinant fusion protein of murine IL-35 and human IgG1 Fc fragment (rIL-35) reduced Th2 cytokines (IL-4 and IL-5) in vitro. However, it is unclear whether IL-35 can attenuate nasal allergic responses and symptoms of allergic rhinitis in vivo.

Methods

To investigate the in vivo effect of IL-35 on allergic rhinitis in mice, mice were sensitized with ovalbumin (OVA). Intranasal administration of rIL-35 and intranasal challenge of OVA were then performed. Nasal symptoms were estimated after the last nasal challenge. Nasal tissue and cervical lymph nodes (CLN) were collected. OVA-specific IgE in sera, OVA-specific T cell response, and the production of cytokines (IL-4, IL-5, and IL-10) stimulated by the OVA antigen were measured. The transcription level of Foxp3 and the frequency of CD4⁺CD25⁺ regulatory T cells were also measured.

Results

rIL-35 significantly inhibited the number of sneezes and nasal rubbing movements. It also reduced the number of eosinophils in the nasal mucosa and significantly decreased the level of OVA-specific IgE, the OVA-specific T cell proliferation, and the production of IL-4 and IL-5. Furthermore, rIL-35 significantly increased the production of IL-10, the transcription level of Foxp3, and the frequency of CD4⁺CD25⁺ regulatory T cells.

Conclusions

This study showed for the first time that rIL-35 inhibits nasal allergic responses and symptoms in mice, and that rIL-35 increases IL-10, Foxp3, and CD4⁺CD25⁺ regulatory T cells in CLN. This study also suggests that intranasal administration of IL-35 can attenuate allergic rhinitis.

SiRNA In Vivo-Targeted Delivery to Murine Dendritic Cells by Oral Administration of Recombinant Yeast

SiRNA therapeutics promise a future where any target in the transcriptome could be potentially addressed. However, the delivery of SiRNAs and targeting of particular cell types or organs are major challenges. A novel, efficient, and safe delivery system for promising the introduction of SiRNAs into particular cell types within living organisms is of great significance. Our previous studies have proved that recombinant protein (MSTN) and exogenous gene (EGFP) as vaccines, and furthermore functional CD40 shRNA expression can be delivered into dendritic cells (DCs) in mouse by oral administration of recombinant yeast (Saccharomyces cerevisiae). Here, we describe the details of the promising and innovative approach based on oral administration of recombinant yeast that allows in vivo-targeted delivery of functional SiRNA to murine intestinal DCs.

Effect of RNA interference therapy on the mice eosinophils CCR3 gene and granule protein in the murine model of allergic rhinitis

OBJECTIVE

To observe the clinical manifestations of allergic rhinitis mice and the expression changes of the eosinophils CCR3 and the granule protein mRNA in the bone marrow, peripheral blood and nasal lavage fluid.

METHODS

Twenty-four BALB/c mice were randomly divided into the control group, PBS therapy group, siRNA therapy group and the CCR3 siRNA therapy group (n=6). Allergic rhinitis model were sensitized and stimulated by ovalbunfin, and CCR3 siRNA therapy group were administered with CCR3 transnasally before stimulated. The levels of the eosinophils CCR3, MBP, ECP and EPO in bone marrow, peripheral blood and nasal lavage fluid were detected by RT-PCR.

RESULTS

Compared to the control group and CCR3 siRNA therapy group, the nasal mucosa of the PBS therapy group and siRNA therapy group developed epithalaxy, goblet cells hyperplasia, squamous epithelium metaplasia, epithelium necrosis, lamina propria and submucosa gland hyperplasia, vasodilatation, tissue edema, and the characterized eosinophil infiltration. RT-PCR indicated that the CCR3 mRNA, MBP, ECP and EPO expression in bone marrow, peripheral blood and nasal lavage fluid of the CCR3 siRNA therapy group was lower than the PBS therapy group and siRNA therapy group (P<0.05).

CONCLUSIONS

The RNA interference therapy to CCR3 by local administration pernasal can suppress the process of the development, migration and invasion of the allergic rhinitis eosinophil, thus can reduce the effect of eosinophils and then reduce the inflammation effect of the allergic rhinitis. It may be a new treatment for respiratory tract allergic inflammation.

In vivo targeted delivery of CD40 shRNA to mouse intestinal dendritic cells by oral administration of recombinant Sacchromyces cerevisiae

Short hairpin RNA (shRNA)-mediated gene regulation is a commonly used technique for gene manipulation. An efficient and safe delivery system is indispensable when shRNA is delivered into living organisms for gene therapy. Previous studies have proved that DNA and protein can be delivered into dendritic cells (DCs) by non-pathogenic Saccharomyces cerevisiae without being degraded. CD40 is closely related to apoptosis of tumor cells and some immune mechanisms. In this study, we demonstrated that recombinant yeast S. cerevisiae efficiently delivered the shRNA of immune-associated gene (CD40) into mouse intestinal DCs via oral administration. Western blot analysis of isolated intestinal DCs indicated that the inhibition of CD40 gene expression reached up to 56-91%. The secretion of cytokines such as interleukin-2 (IL-2), IL-6, IL-10, IL-12, tumor necrosis factor-α and interferon-γ in intestinal DCs had varying degrees of changes. In conclusion, we found that orally administered recombinant yeast can be used as an efficient shRNA delivery system for intestinal DC-specific gene silencing and immunomodulation in vivo.

The significance of immune-related molecule expression profiles in an animal model of Graves' disease

BACKGROUND

The thyrotropin receptor (TSHR) A-subunit has been reported to be a critical autoantigen in the generation of thyroid-stimulating antibodies, thereby causing Graves' disease (GD). However, immune mechanisms associated with GD animal models induced by TSHR A-subunit are poorly understood until now.

METHODS

Female BALB/c mice (n = 23) were randomly divided into two groups, and GD presentation was monitored following injection with either 50 μl phosphate-buffered saline containing 10(9) particles of adenovirus expressing the human TSHR A-subunit (Ad-TSHR289) or the Ad-LacZ control. Expressions of CD40, CD40L, CD80, CD86, CD28, CTLA-4, FOXP3 and IL-17A in various tissues were assessed by quantitative RT-PCR and immunohistochemical assays.

RESULTS

Compared with control group, mice of the hyperthyroid group showed significant elevation of expression in the thyroid of CD40 and CD86, expression in the heart of CD28, CD40 and CD40L and expression in the liver of CD28, CD40 and CD86. Conversely, there was significantly diminished expression of CTLA-4 in the thymus of mice in the hyperthyroid group. Expression of all genes examined was not significantly different in the spleens of mice from either of the groups and CD40L and FOXP3 expression was not detected in the thyroids of hyperthyroid mice.

CONCLUSIONS

The expression profile of multiple immune-related molecules differed in mice in the GD group following Ad-TSHR289 immunization, suggesting that these molecules played a potential role in GD pathogenesis.

Treatment of autoimmune arthritis using RNA interference-modulated dendritic cells

Dendritic cells (DCs) have a dual ability to either stimulate or suppress immunity, which is primarily associated with the expression of costimulatory molecules. Ag-loaded DCs have shown encouraging clinical results for treating cancer and infectious diseases; however, the use of these cells as a means of suppressing immune responses is only recently being explored. Here, we describe the induction of RNA interference through administering short interfering RNA (siRNA) as a means of specifically generating tolerogenic DCs. Knockdown of CD40, CD80, and CD86, prior to loading DCs with the arthritogenic Ag collagen II, led to a population of cells that could effectively suppress onset of collagen-induced arthritis. Maximum benefits were observed when all three genes were concurrently silenced. Disease suppression was associated with inhibition of collagen II-specific Ab production and suppression of T cell recall responses. Downregulation of IL-2, IFN-gamma, TNF-alpha, and IL-17 and increased FoxP3(+) cells with regulatory activity were observed in collagen-induced arthritis mice treated with siRNA-transfected DCs. Collectively, these data support the use of ex vivo gene manipulation in DCs using siRNA to generate tailor-made tolerogenic vaccines for treating autoimmunity.

A novel allergen-specific therapy for allergy using CD40-silenced dendritic cells

BACKGROUND

Induction of RNA interference with small interfering RNA (siRNA) has demonstrated therapeutic potential through the knockdown of target genes. We have previously reported that systemic administration of CD40 siRNA is capable of attenuating allergic symptoms but in an allergen-nonspecific fashion. However, siRNA-based allergen-specific therapy for allergy has not been developed.

OBJECTIVE

We attempted to develop a new allergen-specific therapy for allergy using CD40-silenced and allergen-pulsed dendritic cells (DCs).

METHODS

Bone marrow-derived DCs were silenced with CD40 siRNA and pulsed with ovalbumin (OVA). Mice had allergy after intraperitoneal sensitization with OVA and keyhole limpet hemocyanin, followed by intranasal challenge with the same allergens. The mice were treated with CD40-silenced and OVA-pulsed DCs (CD40-silenced OVA DCs) either before allergic sensitization or after establishing allergic rhinitis.

RESULTS

Mice receiving CD40-silenced OVA DCs either before or after the establishment of allergic rhinitis showed remarkable reductions in allergic symptoms caused by OVA challenge, as well as anti-OVA IgE levels in sera. Additionally, CD40-silenced OVA DCs suppressed eosinophil infiltration at the nasal septum, OVA-specific T-cell responses, T-cell production of IL-4 and IL-5 after stimulation with OVA, and CD4(+)CD25(-) effector T-cell responses. Furthermore, CD40-silenced OVA DCs facilitated the generation of CD4(+)CD25(+) forkhead box protein 3-positive OVA-specific regulatory T cells, which inhibit allergic responses in vivo. However, CD40-silenced OVA DCs suppressed only OVA-specific allergy but did not inhibit keyhole limpet hemocyanin-induced allergy, suggesting that CD40-silenced OVA DCs induce allergen-specific tolerance.

CONCLUSIONS

This study is the first to demonstrate a novel allergen-specific therapy for allergy through DC-mediated immune modulation after gene silencing of CD40.

Impaired olfactory function in mice with allergic rhinitis

OBJECTIVE

It has been reported that olfactory function is impaired in patients with allergic rhinitis. However, the mechanism of olfactory dysfunction in allergic rhinitis remains poorly understood. Because of difficulties in obtaining and analyzing human olfactory mucosa due to both technical and ethical issues, an animal model needs to be established to clarify the mechanism of olfactory dysfunction in allergic rhinitis. The purpose of this study was to study olfactory function and changes in olfactory mucosa using allergic rhinitis mice.

METHODS

A model of allergic rhinitis mice with olfactory dysfunction was developed by sensitizing with ovalbumin (OVA), and intranasally challenging with the same allergen. Olfactory function of mice with or without allergic rhinitis was assessed by odor detection ability test with cycloheximide and local field potential (LFP) with 1-octanal. We also evaluated histological changes in the olfactory mucosa of allergic rhinitis mice by both light and electron microscopy.

RESULTS

Both of odor detection ability test and LFP showed that olfactory function was impaired in mice with allergic rhinitis, but not in mice without allergic rhinitis. Histopathological findings showed prominent infiltration of eosinophils, plasma cells, neutrophils, mast cells, and macrophages in lamina propria of olfactory mucosa of mice with allergic rhinitis, although infiltration of these cells was not seen in control mice. Allergic rhinitis also increased the number and size of glands in olfactory mucosa, suggesting an elevated amount of mucin in olfactory mucosa.

CONCLUSION

This study showed for the first time that mice with allergic rhinitis have impaired olfactory function, increased size and number of olfactory glands, and infiltration of eosinophils, neutrophils, mast cells, plasma cells, and macrophages in the olfactory mucosa. This suggests that allergic reactions are seen in olfactory mucosa of mice with allergic rhinitis, and that greater olfactory gland activity is associated with olfactory dysfunction. Also, this mouse model could provide an expedient system for analyzing mechanisms of olfactory dysfunction.

RNAi-mediated CD40-CD154 interruption promotes tolerance in autoimmune arthritis

INTRODUCTION

We have previously demonstrated that ex vivo inhibition of costimulatory molecules on antigen-pulsed dendritic cells (DCs) can be useful for induction of antigen-specific immune deviation and suppression of autoimmune arthritis in the collagen induced arthritis (CIA) model. The current study evaluated a practical method of immune modulation through temporary systemic inhibition of the costimulatory molecule CD40.

METHODS

Mice with collagen II (CII)-induced arthritis (CIA) were administered siRNA targeting the CD40 molecule. Therapeutic effects were evaluated by clinical symptoms, histopathology, Ag-specific T cell and B cell immune responses.

RESULTS

Systemic administration of CD40-targeting siRNA can inhibit antigen-specific T cell response to collagen II, as well as prevent pathogenesis of disease in both a pre- and post-immunization manner in the CIA model. Disease amelioration was associated with suppression of Th1 cytokines, attenuation of antibody production, and upregulation of T regulatory cells.

CONCLUSIONS

These studies support the feasibility of transient gene silencing at a systemic level as a mechanism of resetting autoreactive immunity.

Oligonucleotide based-strategies for allergy with special reference to siRNA

BACKGROUND

Allergic diseases are a significant global health care problem. Current pharmacological approaches address symptoms but do not alter the underlying immune dysregulation. Current allergen-specific immunotherapy has several drawbacks. Therefore, approaches that attenuate allergic responses safely and effectively at the level of upstream causative events are desirable. Oligonuleotide-based therapies [CpG DNA, antisense oligonucleotides, and small interfering RNA (siRNA)] are promising approaches.

OBJECTIVE/METHODS

We review developments in oligonucleotide-based therapies and the potential of siRNA for treating allergy.

RESULTS/CONCLUSIONS

Strategies with oligonucleotides basically aim to reduce T helper type 2 (Th2) responses. It is controversial whether the reduction of Th2 responses does, in fact, attenuate allergic diseases. Increased understanding of allergic mechanisms will enhance the efficacy of oligonucleotide-based therapy.

Ablation of tumor progression locus 2 promotes a type 2 Th cell response in Ovalbumin-immunized mice

The protein kinase encoded by the Tpl2 proto-oncogene regulates ERK activation and cytokine gene expression in macrophages in response to LPS and TNF-alpha. In this study we show that OVA-immunized Tpl2(-/-) mice express high levels of IgE and develop more severe bronchoalveolar eosinophilic inflammation than Tpl2(+/+) controls, when challenged with OVA intranasally. Bronchoalveolar exudates and supernatants of OVA-stimulated splenocytes from immunized Tpl2(-/-) mice express elevated levels of IL-4 and IL-5, suggesting that Tpl2 ablation promotes the Th2 polarization of the T cell response. Anti-CD3 stimulation of CD4(+) T cells of wild-type and Tpl2 knockout mice revealed that Tpl2 ablation gives rise to a cell autonomous T cell defect that is primarily responsible for the Th2 polarization of the T cell response to Ag. This observation was further supported by experiments addressing the expression of Th1 and Th2 cytokines in OVA-stimulated mixed cultures of CD4(+) T cells from Tpl2(+/+)/OT2 or Tpl2(-/-)/OT2 mice and dendritic cells from Tpl2(+/+) or Tpl2(-/-) mice. Further studies revealed that Th1 cells express significantly higher levels of Tpl2 than Th2 cells. As a result, Tpl2(-/-) Th1 cells exhibit a stronger defect in ERK activation by anti-CD3 than Th2 cells and express low levels of T-bet. Given that the development of Th1 and Th2 cells depends on positive feedback signals from the T cells, themselves, the functional defect of the Tpl2(-/-) Th1 cells provides a mechanistic explanation for the T cell autonomous Th2 polarization in Tpl2(-/-) mice.