High-level expression and purification of the major house dust mite allergen Der p 2 in Escherichia coli

House dust mite allergen Der f 2 drives IL-6 and GM-CSF expression in airway epithelial cells via p38 MAPK/NF-κB signaling

OBJECTIVE

Der f 2, a major allergen derived from Dermatophagoides farinae, is a leading cause of allergic asthma. IL-6 and GM-CSF play essential roles in the exacerbation of asthma. However, the mechanical act by which Der f 2 mediates the expression of IL-6, IL-8, and GM-CSF in airway epithelial cells remains incompletely elucidated. Herein, we aimed to explore the effect of Der f 2 on IL-6 and GM-CSF expression in the human airway epithelial cell BEAS-2B and A549.

METHODS

Recombinant Der f 2 (rDf2) was acquired using Pichia pastoris. BEAS-2B and A549 cells were used as cell model. The expression of genes and proteins and the involvement of the signaling cascade were assessed using RT-PCR, quantitative real-time PCR (qPCR), Western blotting, and ELISA, respectively.

RESULTS

Our findings showed that rDf2 significantly induced mRNA expression and protein production of IL-6 and GM-CSF in BEAS-2B and A549 cells. In contrast, rDf2 did not influence IL-8 expression or production in both cells. Mechanistic studies revealed that rDf2 triggered activation of the p38 MAPK and JNK. Inhibition of p38, but not JNK, significantly attenuated rDf2-induced IL-6 and GM-CSF expression and production.

CONCLUSION

This study demonstrates that Der f 2 promotes the expression and production of the pro-inflammatory cytokines IL-6 and GM-CSF in airway epithelial cells via activation of the p38 signaling pathway. These findings provide insights into the molecular mechanisms that Der f 2 may exacerbate airway inflammation.

A Review: Molecular Chaperone-mediated Folding, Unfolding and Disaggregation of Expressed Recombinant Proteins

The advancements in biotechnology over time have led to an increase in the demand of pure, soluble and functionally active proteins. Recombinant protein production has thus been employed to obtain high expression of purified proteins in bulk. E. coli is considered as the most desirable host for recombinant protein production due to its inexpensive and fast cultivation, simple nutritional requirements and known genetics. Despite all these benefits, recombinant protein production often comes with drawbacks, such as, the most common being the formation of inclusion bodies due to improper protein folding. Consequently, this can lead to the loss of the structure-function relationship of a protein. Apart from various strategies, one major strategy to resolve this issue is the use of molecular chaperones that act as folding modulators for proteins. Molecular chaperones assist newly synthesized, aggregated or misfolded proteins to fold into their native conformations. Chaperones have been widely used to improve the expression of various proteins which are otherwise difficult to produce in E. coli. Here, we discuss the structure, function, and role of major E. coli molecular chaperones in recombinant technology such as trigger factor, GroEL, DnaK and ClpB.

CRM197-Coupled Der p 2 Peptides Suppress Allergic Airway Inflammation in a Der p 2-Induced Asthma Mouse Model

Allergic diseases affect more than 25% of the global population. Der p 2 is the major allergen of the house dust mite (HDM) Dermatophagoides pteronyssinus. Allergen-specific immunotherapy is the only treatment to change the course of allergic diseases. In this study, two synthesized Der p 2 peptides coupled to cross-reacting material 197 (CRM197) showed reduced IgE reactivity and allergenic activity. CRM197-coupled Der p 2 peptides induced rDer p 2-specific IgG1 antibodies in mice, which could inhibit HDM-allergic patients' IgE binding to rDer p 2. The immunity effects of CRM197-coupled Der p 2 peptides were studied in an rDer p 2-induced asthma mouse model. CRM197-coupled Der p 2 peptides can suppress asthmatic airway inflammation in this model. Analysis of IL-4, IL-5, and IFN-γ levels in bronchoalveolar lavage fluid revealed that the suppression was associated with a shift from a Th2 to a Th1 response. Thus, CRM197-bound Der p 2 peptides exhibited less allergenic activity than the rDer p 2 allergen, which preserved immunogenicity and may be candidates for mite allergy vaccines.