Reference : Dust exposure exacerbates the expression of ptx3, a recently discovered acute phase prot...
Scientific congresses and symposiums : Unpublished conference
Life sciences : Veterinary medicine & animal health
Dust exposure exacerbates the expression of ptx3, a recently discovered acute phase protein, in horses’ airways
Ramery, Eve[Université de Liège - ULg > Département de sciences fonctionnelles > Biochimie >]
Bureau, Fabrice[Université de Liège - ULg > Département de sciences fonctionnelles > GIGA-R : Biochimie et biologie moléculaire >]
Lekeux, Pierre[Université de Liège - ULg > Département de sciences fonctionnelles > Physiologie >]
ACCP spring meeting, Stoke Rochford, Lincolnshire
27 mars 2009
[en] PTX3 ; Heaves ; airway obstruction
[en] Heaves is a common cause of recurrent airway obstruction (R.A.O) that occurs in mature horses stabled in a dusty environment. The long pentraxin PTX3 play an important role in the host defence and over-expression of PTX3 may contribute to airways injury. Therefore, we hypothesised that PTX3 may have relevance in the understanding of the pathogenesis of recurrent airway obstruction (R.A.O). In the present study, we first investigated the equine PTX3 (ePTX3) structure by cloning, sequencing and western-blotting. A 120pb deletion was found in the second exon of ePTX3 in comparison to human PTX3. Moreover, an alternative splicing occurs with complete deletion of the second exon, resulting in two forms of the protein, “spliced” (32 kD) and “full length” (42 kD). The pentraxin domain is very well conserved in the two forms with 94% of amino-acids conserved between equines and humans. These findings could have implications for the comprehension of the function of each domain of the protein. Then, we studied the effects of dust exposure and subsequent R.A.O crisis on ePTX3 expression in the broncho-alveolar lavage fluid (BALF) and the bronchial epithelial cells. PTX3 could be detected in BALF macrophages, neutrophils, eosinophils and bronchial epithelial cells. It was over-expressed in the BALF supernatant from RAO-affected horses in crisis. Dust exposure induced PTX3 in BALF macrophages either in healthy horses or in R.A.O-affected horses. Conversely, PTX3 was strongly over-expressed in the bronchial epithelial cells from R.A.O-affected horses in crisis. Considering epithelial cells as one of the major cell types in the airways, PTX3 produced at this level may play an important role in inflammatory process. Moreover, it suggests that dust-induced expression of PTX3 is differentially regulated in macrophages and bronchial-epithelial cells. A JNK-dependant, NFκB-independent regulatory pathway has been described in lung epithelial cells. A comparable mechanism could be involved in bronchial epithelial cells. If this is confirmed, PTX3 expression in respiratory epithelial cells could be therapeutically targeted.