Figure 4.miR-146a/b increase in senescent fibroblasts that secrete high levels of inflammatory cytokines. (A) & (B) Proliferating BJ (PD
36) and IMR90 (PD 38) cells were treated with bleomycin to induce
senescence. CM and RNA were harvested 11 d later. (A) Western
analysis for secreted IL-6. (B) Northern analysis for miR-146a. (C)
Northern analysis for miR-146a levels in replicatively senescent BJ and
IMR90 cells. The PD levels at which cells were harvested for analysis is
given below each lane. BJ cells reach complete senescence after
approximately 70 PDs, whereas IMR90 cells are nearly completely senescent
by PD61. (D)
& (E) Proliferating IMR90 cells (PD40) were either untreated
(Pro), treated with bleomycin (DS) or infected with the lentivirus
expressing oncogenic RAS (RAS). CM and RNA were collected 11 days after
treatment or infection. (D) Western analysis for IL-6 in CM. (E)
Northern analysis for miR-146a and U6 (control) levels.
