Soluble factors from biofilms increase caspase activity in hBMSCs. (A) Caspase-3/7 activity of hBMSCs over a 7 day period following exposure to media containing 25% PBS (vehicle control), lipoteichoic acid (LTA, 10 μg/mL at 25%, Gram-positive cell wall component), S. aureus UAMS-1 planktonic-conditioned media (PCM), and S. aureus UAMS-1 biofilm-conditioned media (BCM). (B) Caspase-3/7 activity of hBMSCs over a 7 day period following exposure to media containing 25% PBS (vehicle control), lipopolysaccharides (LPS, 10 μg/mL at 25%, Gram-negative cell wall component), P. aeruginosa SAMMC-418 PCM, and P. aeruginosa SAMMC-418 BCM. Values are expressed as a ratio of the untreated growth control (untreated hBMSCs exposed to complete growth media, indicated by dashed lines) and represent the average ± SEM. *,#,+ p < 0.05 compared to day 1, 3 and 7 controls, respectively. (C) Western blot analysis of Caspase-3 antibody on hBMSC lysates, illustrating the presence of the endogenous uncleaved form (35 kDa) and the activated cleaved form (17-19 kDa). (D) Semiquantitative analysis of the ratio of activated (cleaved) to inactive (uncleaved) levels of caspase-3 as determined by densitometric analysis. Protein levels were normalized to levels GAPDH probed on the same membrane. Staurosporine, an apoptic inducing agent was included as a positive control for apoptosis.