Central Role of Core Binding Factor β2 in Mucosa-Associated Lymphoid Tissue Organogenesis in Mouse

Eyedrop vaccination: an immunization route with promises for effective responses to pandemics

INTRODUCTION

Mucosal vaccines have several advantages over parenteral vaccines. They induce both systemic and mucosal antigen-specific immune responses, allow easy administration, and bypass the need for trained medical personnel.

AREAS COVERED

Eye mucosa is a novel route of mucosal vaccine administration. Eyedrop vaccination induces systemic and mucosal immune responses similar to other forms of mucosal vaccines such as oral and intranasal vaccines.

EXPERT OPINION

Eyedrop vaccines are free of serious adverse side effects like the infiltration of CNS by pathogens. Studies over the years have shown promising results for eye drop vaccines against infectious agents like the influenza virus, Salmonella typhi, and Escherichia coli in animal models. Such efficacy and safety of eyedrop vaccination enable the application of eyedrop vaccines against other infectious diseases as well as chronic diseases. In this review of published literature, we examine the mechanism, efficacy, and safety of eyedrop vaccines and contemplate their role in times of a pandemic.

BLT1 mediates commensal bacteria-dependent innate immune signals to enhance antigen-specific intestinal IgA responses

Leukotriene B₄ receptor 1 (BLT1) triggers the migration of granulocytes and activated T cells; however, its role in B-cell function remains unclear. Here we report that BLT1 is required to induce the production of antigen-specific IgA against oral vaccine through mediating innate immune signals from commensal bacteria. B cells acquire BLT1 expression during their differentiation to IgA⁺ B cells and plasma cells in Peyer's patches and the small intestinal lamina propria, respectively. BLT1 KO mice exhibited impaired production of antigen-specific fecal IgA to oral vaccine despite normal IgG responses to systemically immunized antigen. Expression of MyD88 was decreased in BLT1 KO gut B cells and consequently led to diminished proliferation of commensal bacteria-dependent plasma cells. These results indicate that BLT1 enhances the proliferation of commensal bacteria-dependent IgA⁺ plasma cells through the induction of MyD88 and thereby plays a key role in the production of antigen-specific intestinal IgA.

Immunological association of inducible bronchus-associated lymphoid tissue organogenesis in Ag85B-rHPIV2 vaccine-induced anti-tuberculosis mucosal immune responses in mice

We previously reported that Ag85B-expressing human parainfluenza type 2 virus (Ag85B-rHPIV2) was effective as a nasal vaccine against tuberculosis in mice; however, the mechanism by which it induces an immune response remains to be investigated. In the present study, we found that organogenesis of inducible bronchus-associated lymphoid tissue (iBALT) played a role in the induction of antigen-specific T cells and IgA antibody responses in the lung of mice intra-nasally administered Ag85B-rHPIV2. We found that expression of Ag85B was dispensable for the development of iBALT, suggesting that HPIV2 acted as an iBALT-inducing vector. When iBALT organogenesis was disrupted in Ag85B-rHPIV2-immunized mice, either by neutralization of the lymphotoxin pathway or depletion of CD11b⁺ cells, Ag85B-specific immune responses (i.e. IFN γ-producing T cells and IgA antibody) were diminished in the lung. Furthermore, we found that immunization with Ag85B-rHPIV2 induced neutrophil and eosinophil infiltration temporally after the immunization in the lung. Thus, our results show that iBALT organogenesis contributes to the induction of antigen-specific immune responses by Ag85B-rHPIV2 and that Ag85B-rHPIV2 provokes its immune responses without inducing long-lasting inflammation.

The 17,18-epoxyeicosatetraenoic acid-G protein-coupled receptor 40 axis ameliorates contact hypersensitivity by inhibiting neutrophil mobility in mice and cynomolgus macaques

BACKGROUND

Metabolites of eicosapentaenoic acid exert various physiologic actions. 17,18-Epoxyeicosatetraenoic acid (17,18-EpETE) is a recently identified new class of antiallergic and anti-inflammatory lipid metabolite of eicosapentaenoic acid, but its effects on skin inflammation and the underlying mechanisms remain to be investigated.

OBJECTIVE

We evaluated the effectiveness of 17,18-EpETE for control of contact hypersensitivity in mice and cynomolgus macaques. We further sought to reveal underlying mechanisms by identifying the responsible receptor and cellular target of 17,18-EpETE.

METHODS

Contact hypersensitivity was induced by topical application of 2,4-dinitrofluorobenzene. Skin inflammation and immune cell populations were analyzed by using flow cytometric, immunohistologic, and quantitative RT-PCR analyses. Neutrophil mobility was examined by means of imaging analysis in vivo and neutrophil culture in vitro. The receptor for 17,18-EpETE was identified by using the TGF-α shedding assay, and the receptor's involvement in the anti-inflammatory effects of 17,18-EpETE was examined by using KO mice and specific inhibitor treatment.

RESULTS

We found that preventive or therapeutic treatment with 17,18-EpETE ameliorated contact hypersensitivity by inhibiting neutrophil mobility in mice and cynomolgus macaques. 17,18-EpETE was recognized by G protein-coupled receptor (GPR) 40 (also known as free fatty acid receptor 1) and inhibited chemoattractant-induced Rac activation and pseudopod formation in neutrophils. Indeed, the antiallergic inflammatory effect of 17,18-EpETE was abolished in the absence or inhibition of GPR40.

CONCLUSION

17,18-EpETE inhibits neutrophil mobility through GPR40 activation, which is a potential therapeutic target to control allergic inflammatory diseases.

The Role of MicroRNA-143-5p in the Differentiation of Dental Pulp Stem Cells into Odontoblasts by Targeting Runx2 via the OPG/RANKL Signaling Pathway

This study aims to elucidate the mechanisms by which microRNA-143-5p (miR-143-5p) targets runt-related transcription factor 2 (Runx2) in the differentiation of dental pulp stem cells (DPSCs) into odontoblasts, through regulating the osteoprotegerin receptor activator of the nuclear factor-κB ligand (OPG/RANKL) signaling pathway. Following transfection, DPSCs were divided into blank, control, miR-143-5p mimics, miR-143-5p inhibitors, miR-143-5p inhibitors + siRunx2 and siRunx2 groups. Alkaline phosphatase (ALP) activity and mineralized nodules were detected using ALP kit and alizarin red staining. Quantitative reverse transcriptase real time PCR (qRT-PCR) was conducted to measure mRNA expressions of miR-143-5p, Runx2, OPG, and RANKL. Western blotting was used to assess protein expression of odontoblast differentiation-related proteins. Transwell assay and an extracellular matrix (ECM) adhesion cell assay were employed to examine cell migration and cell adhesion. Compared with the blank group, the miR-143-5p mimics and siRunx2 groups showed decreased ALP activity, decreased mineralized nodules and displays of calcium. Fewer migrated cells, weakened cell adhesion, decreased protein expression of dentin phosphoprotein (DPP), dentin sialoprotein (DSP), dentin matrix protein 1 (DMP1), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), OPG and Runx2, and increased RANKL protein expressions were observed. Additionally, opposite results were observed in the miR-143-5p inhibitors group, demonstrating that down-regulated miR-143-5p promotes the differentiation of DPSCs into odontoblasts by enhancing Runx2 expression via the OPG/RANKL signaling pathway. Based on findings in this study, it is postulated that the enhancement of Runx2 expression via the regulation of the OPG/RANKL signaling pathway could be a beneficial approach for dental pulp regeneration. J. Cell. Biochem. 119: 536-546, 2018. © 2017 Wiley Periodicals, Inc.

Cbfb2 Isoform Dominates More Potent Cbfb1 and Is Required for Skeletal Development

Cbfb is a cotranscription factor that forms a heterodimer with Runx proteins Runx1, Runx2, and Runx3. It is required for fetal liver hematopoiesis and skeletal development. Cbfb has two functional isoforms, Cbfb1 and Cbfb2, which are formed by alternative splicing. To address the biological functions of these isoforms in skeletal development, we examined Cbfb1(-/-) and Cbfb2(-/-) mouse embryos. Intramembranous and endochondral ossification was retarded and chondrocyte and osteoblast differentiation was inhibited in Cbfb2(-/-) embryos but not in Cbfb1(-/-) embryos. Cbfb2 mRNA was upregulated in calvariae, limbs, livers, thymuses, and hearts of Cbfb1(-/-) embryos but Cbfb1 mRNA was not in those of Cbfb2(-/-) embryos, and the total amount of Cbfb1 and Cbfb2 mRNA in Cbfb1(-/-) embryos was similar to that in wild-type embryos but was severely reduced in Cbfb2(-/-) embryos. The absolute numbers of Cbfb2 mRNA in calvariae, limbs, livers, thymuses, and brains in wild-type embryos were about three times higher than those of Cbfb1 in the respective tissue. The levels of Runx proteins were reduced in calvariae, limbs, and primary osteoblasts from Cbfb2(-/-) embryos, but the reduction in Runx2 protein was very mild. Furthermore, the amounts of Runx proteins and Cbfb in Cbfb2(-/-) embryos differed similarly among skeletal tissues, livers, and thymuses, suggesting that Runx proteins and Cbfb are mutually required for their stability. Although Cbfb1(-/-) embryos developed normally, Cbfb1 induced chondrocyte and osteoblast differentiation and enhanced DNA binding of Runx2 more efficiently than Cbfb2. Our results indicate that modulations in the relative levels of the isoforms may adjust transcriptional activation by Runx2 to appropriate physiological levels. Cbfb2 was more abundant, but Cbfb1 was more potent for enhancing Runx2 activity. Although only Cbfb2 loss generated overt skeletal phenotypes, both may play major roles in skeletal development with functional redundancy. © 2016 American Society for Bone and Mineral Research.

Expression and function of osteogenic genes runt-related transcription factor 2 and osterix in orthodontic tooth movement in rats

OBJECTIVE

To investigate the expression and function of osteogenic genes osterix (OSX) and runt-related transcription factor 2 (RUNX2) in the rat periodontal tissues under orthodontic force for the remodeling of the periodontal tissues.

METHODS

24 Wistar rats were randomly divided into 4 groups of orthodontic tooth movements for 1, 3, and 7 days (experimental groups) and control group (without orthodontic force). The expression of RUNX2 and OSX in the periodontal tissues was analyzed using real time PCR for mRNA and Western blot analysis for protein. The data were also analyzed for involvement of the two genes in signal pathways using bioinformatics tools.

RESULTS

The mRNA levels of RUNX2 and OSX increased in the periodontal tissues after subjected to the orthodontic force for 1 to 7 days, with the highest level occurring at day 7. The relative expression levels of RUNX2 and OSX mRNA were 1.85 ± 0.12, 304 ± 0.06 and 4.16 ± 0.068, and 1.52 ± 0.09, 1.83 ± 0.03 and 2.56 ± 0.06 at day 1, 3 and 7, respectively. The results of Western blot analysis were consistent with the mRNA results.

CONCLUSION

In orthodontic tooth movement, the expression of RUNX2 and OSX was upregulated as a result of external stimulation, suggesting that the two genes is involved in periodontal tissue remodeling and plays an important role in periodontal tissue remodeling.