The tyrosine kinase inhibitor dasatinib reduces lung inflammation and remodelling in experimental allergic asthma

Abstract

Background and purpose: Asthma is characterized by chronic lung inflammation and airway hyperresponsiveness. Despite recent advances in understanding of its pathophysiology, asthma remains a major public health problem, and new therapeutic strategies are urgently needed. In this context, we sought to ascertain whether treatment with the TK inhibitor dasatinib might repair inflammatory and remodelling processes, thus improving lung function, in a murine model of asthma.

Experimental approach: Animals were sensitized and subsequently challenged, with ovalbumin (OVA) or saline. Twenty-four hours after the last challenge, animals were treated with dasatinib, dexamethasone, or saline, every 12 h for 7 consecutive days. Twenty-four hours after the last treatment, the animals were killed, and data were collected. Lung structure and remodelling were evaluated by morphometric analysis, immunohistochemistry, and transmission electron microscopy of lung sections. Inflammation was assessed by cytometric analysis and ELISA, and lung function was evaluated by invasive whole-body plethysmography.

Key results: In OVA mice, dasatinib, and dexamethasone led to significant reductions in airway hyperresponsiveness. Dasatinib was also able to attenuate alveolar collapse, contraction index, and collagen fibre deposition, as well as increasing elastic fibre content, in OVA mice. Concerning the inflammatory process, dasatinib reduced inflammatory cell influx to the airway and lung-draining mediastinal lymph nodes, without inducing the thymic atrophy promoted by dexamethasone.

Conclusions and implications: In this model of allergic asthma, dasatinib effectively blunted the inflammatory and remodelling processes in asthmatic lungs, enhancing airway repair and thus improving lung mechanics.

Figure 1

Dasatinib mitigated the inflammatory process in bronchoalveolar lavage fluid (BALF) (A) and blood (B). Data expressed as mean ± SD of six mice per group. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.

Figure 2

Dasatinib mitigated the inflammatory process in (A) mediastinal lymph nodes, (B) thymus, and (C) bone marrow. Data expressed as mean ± SD of six mice per group. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.

Figure 3

Dasatinib decreased asthmatic mediator levels in lung tissue homogenate. Data expressed as mean ± SD of seven mice per group. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.

Figure 4

Lung remodelling was mitigated with the use of dasatinib. (A) Alveolar duct smooth muscle α‐actin, (B) alveolar septa elastic fibres, and (C) airway elastic fibres. Data expressed as mean ± SD of seven mice per group. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.

Figure 5

Dasatinib reduced collagen fibre content. (A) Collagen fibre content, (B) Procollagen (PC) I mRNA expression, (C) Procollagen (PC) III mRNA expression, and (D) TGF‐β mRNA expression. Data expressed as mean ± SD of seven mice per group. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.

Figure 6

Dasatinib attenuated lung and airway ultrastructural changes. Representative electron microscopy images of distal airway tissue from animals with experimental allergic asthma. (A) Smooth muscle hypertrophy, (B) collagen deposition and (C) mitochondrial damage. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.

Figure 7

Dasatinib improved lung function. (A) Elastance and (B) resistance. Data expressed as mean ± SD of seven mice per group. CTRL, mice sensitized/challenged with saline; OVA, mice sensitized/challenged with ovalbumin; DEXA, mice treated with dexamethasone (1 mg⋅kg⁻¹); DAS1, mice treated with dasatinib (1 mg⋅kg⁻¹); DAS10, mice treated with dasatinib (10 mg⋅kg⁻¹). * P < 0.05; significantly different from CTRL; # P < 0.05; significantly different from OVA.