Research Paper Volume 1, Issue 4 pp 402—411

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.