Rhinovirus-mediated changes in airway smooth muscle responsiveness: induced autocrine role of interleukin-1beta

An important interplay exists between specific viral respiratory pathogens, most commonly rhinovirus (RV), and altered airway responsiveness in the development and exacerbations of asthma. Given that RV infection reportedly induces the release of various cytokines in different cell types and that the reported effects of RV on airway smooth muscle (ASM) responsiveness are highly comparable to those obtained in ASM exposed to the proinflammatory cytokine interleukin (IL)-1beta, this study examined whether RV (serotype 16)-mediated pertubations in ASM responsiveness are mechanistically coupled to altered induced expression and action of IL-1beta in RV-exposed isolated rabbit and human ASM tissue and cultured cells. Relative to control tissues, ASM inoculated with RV exhibited significantly increased maximal isometric contractility to ACh (P < 0.01) and attenuated relaxation to isoproterenol (P < 0. 005). In extended studies, we found that 1) the RV-induced changes in ASM responsiveness were ablated by pretreating the tissues with the IL-1 recombinant human receptor antagonist; 2) in contrast to their respective controls, RV-inoculated ASM tissue and cultured cells exhibited progressively induced expression of IL-1beta mRNA and elaboration of IL-1beta protein at 6 and 24 h after viral exposure; and 3) the latter effect of RV was inhibited in the presence of a monoclonal antibody to intercellular adhesion molecule-1, the endogenous receptor for most RV. Collectively, these observations provide new evidence demonstrating that "pro-asthmatic-like" pertubations in agonist responsiveness elicited in RV-exposed ASM are largely attributed to the induced autologous expression and autocrine action of IL-1beta in the virus-infected ASM.