ovalbumin and 17-18-epoxy-5-8-11-14-eicosatetraenoic-acid

Protein kinase C variants (PKCs) have been involved in the control of airway smooth muscle (ASM) tone, and abnormalities in PKC-dependent signaling have been associated with respiratory diseases such as asthma. In this study, the role of atypical PKCζ in airway hyperresponsiveness was investigated, using an in-vitro model of TNFα-treated human bronchi and an in vivo guinea pig model of chronic asthma. Our results demonstrated that PKCζ-specific inhibition produced a significant increase in isoproterenol sensitivity in TNFα-treated bronchi and ovalbumin (OVA)-sensitized guinea pig bronchi. The role of epoxy-eicosanoids, known to exert anti-inflammatory effects in lung, on PKCζ expression and activity in these models was evaluated. An enhanced PKCζ protein expression was delineated in TNFα-treated bronchi when compared with control (untreated) and epoxy-eicosanoid-treated bronchi. Measurements of Ca(2+) sensitivity, performed in TNFα-treated bronchi, demonstrated that treatment with myristoylated (Myr) PKCζ peptide inhibitor resulted in significant reductions of pCa-induced tension. Epoxy-eicosanoid treatments had similar effects on Ca(2+) sensitivity in TNFα-treated bronchi. In control and epoxy-eicosanoid-treated bronchi, the phosphorylated forms of p38MAPK and CPI-17 were significantly decreased compared with the TNFα-treated bronchi. An enhanced expression of PKCζ was ascertained in our in-vivo model of allergic asthma. Hence an increased Ca(2+) sensitivity could be explained by the phosphorylation of p38-MAPK, which in turn leads to phosphorylation and activation of the CPI-17 regulatory protein. This process was reversed upon treatment with the Myr-PKCζ-peptide inhibitor. The present data provide relevant evidence regarding the role of PKCζ in human and rodent models of airways inflammation.

Topics: Adrenergic beta-2 Receptor Agonists; Animals; Arachidonic Acids; Asthma; Biomechanical Phenomena; Bronchi; Bronchial Hyperreactivity; Bronchodilator Agents; Calcium; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Guinea Pigs; Humans; Intracellular Signaling Peptides and Proteins; Male; Muscle Contraction; Muscle Proteins; Muscle Relaxation; Muscle, Smooth; Ovalbumin; p38 Mitogen-Activated Protein Kinases; Phosphoprotein Phosphatases; Phosphorylation; Pneumonia; Protein Kinase C; Protein Kinase Inhibitors; Tissue Culture Techniques; Tumor Necrosis Factor-alpha; Up-Regulation