STAT1 and cystic fibrosis: However, INF-β significantly decreased LPS-induced pro-IL-1β expression, which was completely abolished when CF were pretreated with Ruxolitinib (Figure 4A) As shown by the use of siRNA, both si-STAT2 and si-STAT3 were involved in IFN-β effects on pro-IL-1β expression on LPS-treated CF, whereas STAT1 was not involved (Figure 4B).