The effect of topical FK506 (tacrolimus) in a mouse model of allergic rhinitis

Tacrolimus (FK506) treatment protects allergen-, IL-5- and IL-13-induced mucosal eosinophilia

Eosinophils are a common clinical feature associated with chronic allergic diseases, and elemental diets, systemic steroids, anti-IL-5 and anti-IL-13 treatment have shown some therapeutic promise. Herein, we present evidence that pre- and post-intraperitoneal administration of tacrolimus (FK506) is very effective in reducing CCR3/Siglec-F⁺ eosinophils in Aspergillus-challenged asthma and EoE, CD2-IL-5 induced global eosinophilia, and DOX regulated IL-13-induced asthma. We used flow cytometry and anti-major basic protein (MBP) immunostaining to examine eosinophils in the spleen, bone marrow, BALF, lung, oesophagus and intestine. Additionally, we also performed ELISA and Western blot analyses to show that tacrolimus treatment also reduces the levels of eosinophil-specific cytokines IL-4, IL-5, IL-13 and TGF-β, eosinophil-specific chemokines Eotaxin-1 and Eotaxin-2, and progenitors of target RCAN1 mRNA and protein levels. Additionally, the current investigations also show that the TGF-β-mediated oesophageal and lung fibrosis is also reduced in Aspergillus-challenged, CD2-IL-5 transgenic and DOX-responsive IL-13 mice. Mechanistically, we show that tacrolimus in vitro treatment inhibited bone marrow-derived eosinophil proliferation and viability by promoting eosinophil apoptosis that may be associated with downregulation of RCAN1. Taken together, we provide in vivo and in vitro evidence that tacrolimus ameliorates eosinophil levels and associated pathogenesis in allergen-, IL-5- and IL-13-induced EoE, EG and asthma pathogenesis. Considering tacrolimus side-effects and reactivity to several other drugs, we propose the topical use of tacrolimus for paediatric and low-dose oral for adult patients as a novel therapeutic strategy for the clinical trial to reduce mucosal eosinophilia first in steroid-refractory or elemental diet non-responsive adult EoE, EG and asthma patients.

Immune Relevant and Immune Deficient Mice: Options and Opportunities in Translational Research

In 1989 ILAR published a list and description of immunodeficient rodents used in research. Since then, advances in understanding of molecular mechanisms; recognition of genetic, epigenetic microbial, and other influences on immunity; and capabilities in manipulating genomes and microbiomes have increased options and opportunities for selecting mice and designing studies to answer important mechanistic and therapeutic questions. Despite numerous scientific breakthroughs that have benefitted from research in mice, there is debate about the relevance and predictive or translational value of research in mice. Reproducibility of results obtained from mice and other research models also is a well-publicized concern. This review summarizes resources to inform the selection and use of immune relevant mouse strains and stocks, aiming to improve the utility, validity, and reproducibility of research in mice. Immune sufficient genetic variations, immune relevant spontaneous mutations, immunodeficient and autoimmune phenotypes, and selected induced conditions are emphasized.

Immunomodulatory effects of tacrolimus (FK506) for the treatment of allergic diseases

Tacrolimus has been used to prevent allograft rejection and also used in kidney, liver and heart transplantations. Various preclinical and clinical studies demonstrated that Tacrolimus possess immunomodulatory and anti-inflammatory properties. The mechanism of action of Tacrolimus in allergic diseases involves calcineurin inhibition, and downregulation of T-cell reactivity, IgE degranulation, and its actions on mast cells, dendritic cells, basophils, eosinophils and inhibition of transcription of proinflammatory cytokines. Herein we reviewed the Pharmacotherapeutic mechanism of action of Tacrolimus in the prevention of asthma, atopic dermatitis, and allergic conjunctivitis.

Characterization of a novel high-dose ovalbumin-induced murine model of allergic sinonasal inflammation

BACKGROUND

Few efficacious topical therapies exist for chronic rhinosinusitis (CRS). The lack of a reproducible mouse model of CRS limits the pilot testing of potential novel anti-inflammatory therapies. Although the ovalbumin-induced mouse model of sinonasal inflammation is commonly used, it is difficult to reproduce and can generate variable histologic results. In this study, we explore a variation of this model in different strains of mice and explore various inflammatory cytokines as reproducible molecular markers of inflammation.

METHODS

Allergic sinonasal inflammation was generated in BALB/c and C57BL/6 mice using intraperitoneal high-dose injections of ovalbumin (Ova; Sigma Chemical Co.) followed by 10 days of high-dose intranasal sensitization. Real-time polymerase chain reaction (RT-PCR) for eotaxin, interleukin 4 (IL-4), and IL-13 were measured from sinonasal mucosa. We also pilot tested a known topical budesonide to characterize the anti-inflammatory response. Histological sections were analyzed for epithelial thickness and eosinophilia.

RESULTS

Both BALB/c and C57BL/6 mice consistently showed increases in T helper 2 (Th2) cytokines after sensitization with high-dose Ova (p < 0.0001) when compared to controls. There were also significant increases in epithelial thickening in Ova-sensitized mice and eosinophilia in both BALB/c and C57BL/6 strains. In addition, topical budesonide significantly reduced anti-inflammatory cytokines, eosinophilia, and epithelial thickness.

CONCLUSION

Our variation of the ovalbumin-induced mouse model of sinonasal inflammation in both BALB/c and C57BL/6 mice provides an efficacious model for testing potential topical anti-inflammatory therapies for CRS. The utilization of sinonasal mucosal Th2 cytokines along with histologic markers provides a consistent and quantifiable marker of inflammation in assessing the efficacy of candidate drugs.

Essential Contribution of CD4+ T Cells to Antigen-Induced Nasal Hyperresponsiveness in Experimental Allergic Rhinitis

Nasal hyperresponsiveness (NHR) is a characteristic feature of allergic rhinitis (AR); however, the pathogenesis of NHR is not fully understood. In this study, during the establishment of an experimental AR model using ovalbumin-immunized and -challenged mice, augmentation of the sneezing reaction in response to nonspecific proteins as well as a chemical stimulant was detected. Whether NHR is independent of mast cells and eosinophils was determined by using mast cell- and eosinophil-deficient mice. NHR was suppressed by treatment with anti-CD4 antibody, suggesting the pivotal contribution of CD4+ T cells. Furthermore, antigen challenge to mice to which in vitro-differentiated Th1, Th2, and Th17 cells but not naïve CD4+ T cells had been adoptively transferred led to the development of equivalent NHR. Since antigen-specific IgE and IgG were not produced in these mice and since antigen-specific IgE-transgenic mice did not develop NHR even upon antigen challenge, humoral immunity would be dispensable for NHR. CD4+ T cells play a crucial role in the pathogenesis of AR via induction of NHR, independent of IgE-, mast cell-, and eosinophil-mediated responses.