Der p2‑A20 DNA vaccine attenuates allergic inflammation in mice with allergic rhinitis

Sialic acid-modified der p 2 allergen exerts immunomodulatory effects on human PBMCs

Background

House dust mite extract-based allergen immunotherapy (AIT) to treat house dust mite allergy is substantially effective but still presents some safety and efficacy concerns that warrant improvement. Several major allergen-based approaches to increase safety and efficacy of AIT have been proposed. One of them is the use of the group 2 allergen, Der p 2.

Objective

We sought to investigate the immunomodulatory effects of sialic acid-modified major allergen recombinant Der p 2 (sia-rDer p 2) on PBMCs from healthy volunteers.

Methods

We activated PBMCs with anti-CD3/CD28 antibodies and incubated them at 37°C for 6 days in the presence or absence of either native rDer p 2 or α2-3 sialic acid-modified rDer p 2 (sia-rDer p 2). We assessed the changes in CD4+ T-cell activation and proliferation by flow cytometry and changes in T-lymphocyte cytokine production in cell culture supernatant by ELISA.

Results

We observed that PBMCs treated with sia-rDer p 2 presented with a markedly decreased expression of CD69 and an increased abundance of LAG-3+ lymphocytes compared with cells treated with rDer p 2. Moreover, PBMCs treated with sia-rDer p 2 showed a reduced production of IL-4, IL-13, and IL-5 and displayed a higher IL-10/IL-5 ratio compared with rDer p 2-treated PBMCs.

Conclusions

We demonstrate that sia-rDer p 2 might be a safer option than native rDer p 2 for Der p 2-specific AIT. This is most relevant in the early phase of AIT that is often characterized by heightened TH2 responses, because sia-rDer p 2 does not enhance the production of TH2 cytokines.

Allergen immunotherapy in China

Allergen immunotherapy (AIT) is an etiological treatment strategy that involves administering escalating doses of clinically relevant allergens to desensitize the immune system. It has shown encouraging results in reducing allergy symptoms and enhancing patients' quality of life. In this review, we offer a thorough overview of AIT in China, examining its efficacy, safety, current practices, and prospects. We further underscore the progress made in AIT research and clinical applications, as well as the distinct challenges and opportunities that China faces in this area.

Current research into A20 mediation of allergic respiratory diseases and its potential usefulness as a therapeutic target

Allergic airway diseases are characterized by excessive and prolonged type 2 immune responses to inhaled allergens. Nuclear factor κB (NF-κB) is a master regulator of the immune and inflammatory response, which has been implicated to play a prominent role in the pathogenesis of allergic airway diseases. The potent anti-inflammatory protein A20, termed tumor necrosis factor-α-inducible protein 3 (TNFAIP3), exerts its effects by inhibiting NF-κB signaling. The ubiquitin editing abilities of A20 have attracted much attention, resulting in its identification as a susceptibility gene in various autoimmune and inflammatory disorders. According to the results of genome-wide association studies, several TNFAIP3 gene locus nucleotide polymorphisms have been correlated to allergic airway diseases. In addition, A20 has been found to play a pivotal role in immune regulation in childhood asthma, particularly in the protection against environmentally mediated allergic diseases. The protective effects of A20 against allergy were observed in conditional A20-knockout mice in which A20 was depleted in the lung epithelial cells, dendritic cells, or mast cells. Furthermore, A20 administration significantly decreased inflammatory responses in mouse models of allergic airway diseases. Here, we review emerging findings elucidating the cellular and molecular mechanisms by which A20 regulates inflammatory signaling in allergic airway diseases, as well as discuss its potential as a therapeutic target.

Targeting a novel hsa_circ_0000520/miR-556-5p/NLRP3 pathway-mediated cell pyroptosis and inflammation attenuates ovalbumin (OVA)-induced allergic rhinitis (AR) in mice models

OBJECTIVES

The circRNAs-miRNAs-mRNAs competing endogenous RNA (ceRNA) networks involve in regulating the development of various inflammation-associated diseases, including allergic rhinitis (AR), and the present study aimed to identify novel AR-associated ceRNA networks.

METHODS

The mRNA and protein levels of the associated genes were, respectively, examined by real-time qPCR and western blot analysis. The targeting sites in miR-556-5p and NLRP3 were validated by performing dual-luciferase reporter gene system assay. ELISA was used to measure inflammatory cytokines secretion, and CCK-8 assay was conducted to determine cell proliferation.

RESULTS

Here, we first identified a hsa_circ_0000520/miR-556-5p/NLRP3 signaling cascade triggered epithelium pyroptosis and inflammation to regulate the development of AR in cellular and mice models. Specifically, the pyroptosis-associated biomarkers (NLRP3, ASC, IL-1β and IL-18) and pro-inflammatory cytokines (OVA-specific IgE, TNF-α, IL-4 and IL-5) were upregulated in the nasal subjects collected from AR patients and ovalbumin (OVA)-induced AR mice models, compared to their normal counterparts. Next, using the ceRNA networks analysis software, we screened out a hsa_circ_0000520/miR-556-5p axis that potentially regulated NLRP3 in the human nasal epithelial cell line. Mechanistically, miR-556-5p targeted both hsa_circ_0000520 and 3' untranslated region (3'UTR) of NLRP3, and knock-down of hsa_circ_0000520 inactivated NLRP3-mediated epithelium pyroptosis through miR-556-5p in a ceRNA-dependent manner. Furthermore, we proved that both hsa_circ_0000520 ablation and miR-556-5p overexpression suppressed NLRP3-mediated cell pyroptosis to attenuate AR in mice models.

CONCLUSIONS

Taken together, we evidenced that targeting the hsa_circ_0000520/miR-556-5p/NLRP3 signaling pathway was a novel AQ1strategy to ameliorate AR progression; however, future clinical data are still required to validate our preliminary results.

Formulations for Allergen Immunotherapy in Human and Veterinary Patients: New Candidates on the Horizon

Allergen immunotherapy is currently the only causal treatment for allergic diseases in human beings and animals. It aims to re-direct the immune system into a tolerogenic or desensitized state. Requirements include clinical efficacy, safety, and schedules optimizing patient or owner compliance. To achieve these goals, specific allergens can be formulated with adjuvants that prolong tissue deposition and support uptake by antigen presenting cells, and/or provide a beneficial immunomodulatory action. Here, we depict adjuvant formulations being investigated for human and veterinary allergen immunotherapy.