Fig. 6.
Persistent LPS treatment of NHCs induces expression of SASP components. (A) IL-6 mRNA expression was assessed by qPCR at 1, 6, and 10 days of LPS treatment. By day 10, expression is significantly elevated (~5-fold > control; ~2-fold > 1 day LPS-treatment). (B) IL-8 mRNA expression is significantly increased by day 10 (~5-fold > control; ~1.5-fold > 1 day LPS-treatment). The delayed response observed in IL-8 (as well as IL-6) expression following an initial acute response is consistent with the time-dependent induction of senescence as demonstrated in other cell types and culture models.33 (C) CCL2 mRNA expression is significantly increased by day 10 (~4.7-fold > control; ~1.9-fold > 1 day LPS-treatment). (D) ELISA of conditioned media from 10-day LPS-treated NHCs demonstrating significantly increased IL-6, IL-8, and CCL2 protein expression compared to control.