Vismodegib, a sonic hedgehog signalling blockade, ameliorates ovalbumin and ovalbumin/lipopolysaccharide-induced airway inflammation and asthma phenotypical models.

AIMS

Asthmatics exhibit clinical fluctuations between manageable and treatment-resistant phenotypes as a worldwide socioeconomic health burden. Sonic Hedgehog (Shh) genes mediate regulatory pulmonary cell renewal in adults and contribute to the pathogenesis of high phenotypic asthma which depends mainly on T helper-2 (Th-2) cells and related cytokines. However, the exact pathophysiological roles of Shh molecular signalling in the Th-17-dependent low phenotypic allergic airway inflammation and asthma are not evidenced previously.

MAIN METHODS

Ovalbumin (OVA) and OVA/lipopolysaccharide (LPS)-sensitized and challenged BALB/c mice were enrolled currently to assess the Shh signalling proteins. Furthermore, the effects of vismodegib, a Smo inhibitor, on the modulation of Shh signalling were compared to dexamethasone. The asthma phenotypes were confirmed by serum total immunoglobulin-E (IgE), bronchoalveolar lavage (BAL) fluid white blood cell counts, lung interleukins, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, and histopathological changes, and scoring.

KEY FINDINGS

Mice challenged with OVA or OVA/LPS showed upregulated lung Shh, patched (Ptch1), smoothened (Smo), and Gli1 proteins. Vismodegib in the two experimental phenotypes of asthma showed reduced airway inflammation and remodelling. Additionally, vismodegib reduced the eosinophilia and neutrophilia reported in high and low asthma types, respectively. Moreover, vismodegib and dexamethasone exhibited negative feedback control throughout the enhanced Shh signalling cascades, including Shh, Ptch1, and Gli1 in several asthma models.

SIGNIFICANCE

In conclusion, Shh signalling partially elucidates the OVA/LPS-challenged mice with severe asthma, which proposes a new promising molecular therapeutic target. Furthermore, Smo inhibition by vismodegib has therapeutic potential in both experimental eosinophilic and neutrophilic allergic airway diseases.