Abstract
Drug resistance and the harmful side effects accompanying the prolonged corticosteroid treatment of chronic pulmonary diseases prompted the development of more specific anti-inflammatory approaches. Several strategies aiming to block IL4R alpha, the receptor for a key pro-inflammatory pathway, were investigated. However, their efficiency was limited, mostly due to the systemic or subcutaneous route of administrations. In this paper, we examined the ability of an intranasal treatment with biocompatible nanoparticles targeting IL4R alpha to control lung inflammation in ovalbumin (OVA)-sensitized mice. OVA-sensitized mice were treated with anti-IL4R alpha-conjugated nanoparticles. The levels of pro-inflammatory cytokines in the lungs and broncho-alveolar lavage fluid (BALF) were determined using a cytokine array assay. The effects of nanoparticle treatment on the activation of lung inflammatory cells and their ability to proliferate and produce cytokines were determined using fluorescence-activated cell sorting (FACS) analysis. Lung inflammation was also monitored using immunohistochemical staining. Treatment with the anti-IL4R alpha nanoparticles significantly decreased pro-inflammatory cytokine expression and release in BALF and airway lung tissue in mice. The numbers of lung tissue lymphocytes, neutrophils and eosinophils were also decreased. Interestingly, anti-IL4R alpha nanoparticles deactivated CD4 and CD8 T cells in lung tissue and inhibited their ability to produce pro-inflammatory cytokines to a significantly lower level than the treatment with free anti-IL4R alpha. Moreover, they induced a sustained low level of lung inflammation for 1 week following the last instillation compared with the treatment with free anti-IL4R alpha antibodies. Together, this data suggested that the enhanced tissue penetrability and sustainability of these nanoparticles improved the strength and durability of the immunosuppressive effects of anti-IL4R alpha.