Mob-1 expression in IL-2-induced ARDS: regulation by TNF-alpha.

We have recently established an animal model of adult respiratory distress syndrome (ARDS)-like microvascular lung injury elicited by infusion of human interleukin-2 (IL-2). Based on the pronounced, transcriptional upregulation of multiple pro-inflammatory mediators in IL-2-induced ARDS, differential display was applied to search for potentially novel genes in this paradigm of lung injury. Differential display on total lung RNA derived from IL-2-challenged rats presented a highly reproducible 3'-UTR fragment profile in which a band (approximately 250 bp), termed B1, was strongly induced. B1 cDNA sequence exhibited 99.14% homology to the 3'-UTR of mob-1, a recently cloned gene belonging to the C-X-C chemokine superfamily. Furthermore, Northern blot analysis showed that IL-2-induced pulmonary mob-1 mRNA was expressed at time points before the onset of lung injury and suppressed after TNF-alpha inhibition. These data imply that lung mob-1 is a novel, highly inducible gene in a clinically relevant model of ARDS and, based on its identification as a chemokine, could participate in the development of lung injury.