Pollen Proteases Play Multiple Roles in Allergic Disorders

Allergic diseases are a major health concern worldwide. Pollens are important triggers for allergic rhinitis, conjunctivitis and asthma. Proteases released upon pollen grain hydration appear to play a major role in the typical immunological and inflammatory responses that occur in patients with allergic disorders. In this study, we aimed to identify specific proteolytic activity in a set of pollens with diverse allergenic potential. Diffusates from Chenopodium album, Plantago lanceolata and Eucalyptus globulus were added to a confluent monolayer of Calu-3 cells grown in an air-liquid interface system. We identified serine proteases and metalloproteinases in all pollen diffusates investigated. Proteases found in these pollen diffusates were shown to compromise the integrity of the lung epithelial barrier by disrupting transmembrane adhesion proteins E-cadherin, claudin-1 and Occludin, as well as, the cytosolic complex zonula occludens-1 (ZO-1) resulting in a time-dependent increase in transepithelial permeability. Tight junction disruption and increased transepithelial permeability facilitates allergen exposure to epithelial sub-layers contributing to the sensitization to a wide range of allergens. These pollen extracts also induced an increase in the release of interleukin 6 (IL-6) and interleukin 8 (IL-8) cytokines measured by flow cytometry possibly as a result of the activation of protease-activated receptors 2 (PAR-2).

Effect of matrix metalloproteinase inhibitor on disrupted E-cadherin after acid exposure in the human nasal epithelium

OBJECTIVE

Laryngopharyngeal reflux disease (LPRD) is one of potential factors in recalcitrant chronic rhinosinusitis with or without polyps. An increase in junctional permeability in the nasal mucosa in LPRD may be due to disrupted protein bridge formation with cell-to-cell adhesion molecules such as E-cadherin. Despite the relationship between nasal mucosal inflammation and LPRD, the clear mechanism by which acid reflux affects the nasal epithelium remains unclear.

METHODS

The expression levels and distribution patterns of E-cadherin in primary culture of nasal epithelial cells after acid exposure with or without dexamethasone and matrix metalloproteinase (MMP) inhibitor were determined using Western blot and immunocytochemistry. The functional roles of MMP inhibitor in maintaining junctional permeability in the nasal epithelium were elucidated by transepithelial permeability test.

RESULTS

By acid exposure to nasal epithelial cells, mature E-cadherin was decreased and cleaved E-cadherin was increased. This was thought to be caused by cleavage of mature E-cadherin between cells and was confirmed by the increment of E-cadherin inside a cell in immunocytochemical evaluation. Whereas disruption of E-cadherin was not recovered by steroid medication with various treatments of dexamethasone, disrupted E-cadherin was restored to normal by inhibition of MMPs with actinonin, a broad MMP inhibitor. This recovery was functionally demonstrated by transepithelial permeability test.

CONCLUSION

Our results suggest that altered expression of E-cadherin in the nasal epithelium by acid exposure may be a possible mechanism for nasal tissue injury in chronic nasal inflammation with LPRD, and that MMP inhibition is a potential treatment.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:E1-E7, 2018.

Impacts of ABCB1 (G1199A) polymorphism on resistance, uptake, and efflux to steroid drugs

1. P-glycoprotein (P-gp) substrates, including steroid drugs, involve in the inter-individual differences in resistant phenotype. This study was performed to evaluate whether G1199A polymorphism in ABCB1 gene can alter the sensitivity, accumulation, and transepithelial efflux to steroids in LLC-PK1 cells. 2. The stable recombinant LLC-PK1 cell lines transfected with ABCB1 1199G and ABCB1 1199A were used to assess the sensitivity, accumulation, and transepithelial permeability to steroids. 3. The cells transfected with 1199A allele displayed stronger resistance to aldosterone, dexamethasone, and cortisol (2.5-, 2.0-, and 1.6-fold, respectively) than cells overexpressing 1199G allele, while the two types of recombinant cells showed a similar resistance to corticosterone. The accumulation of aldosterone, dexamethasone, and cortisol in recombinant 1199A cells were significantly decreased when compared to 1199G cells (2.9-, 4.4-, and 3.9-fold, respectively). The net efflux ratios of P-gp-mediated aldosterone, dexamethasone, and cortisol in cells expressing 1199A allele were apparently greater than cells transfected with 1199G allele (3.3-, 3.5-, and 4.0-fold, respectively). 4. The impacts of ABCB1 (G1199A) single nucleotide polymorphism on the efflux of P-gp substrates presented as drug-specific. Overall, the transport ability of P-gp-dependent steroid drugs in recombinant model overexpressing variant 1199A allele is stronger in comparison to cells overexpressing wild-type 1199G allele. Therefore, the ABCB1 (G1199A) polymorphism may affect effective steroids concentration in target cells by regulating the drug transport and distribution.