TNF-α upregulates the inflammatory profile of MSCs via receptors TNF-RI and TNF-RII. (A) Relative induction of CCL2, CXCL8 and CCL5 in MSCs by TNF-α. Human BM-derived MSCs were stimulated by TNF-α (50 ng/ml) for 24 hours and the expression of the inflammatory chemokines CCL2, CXCL8 and CCL5 in supernatants of MSCs was determined by ELISA, in the linear range of absorbance. Results are from an experiment in which all three chemokines were analyzed in parallel, and the ratios between the three chemokines are representatives of the values obtained in many experimental repeats. (B) Human BM-derived MSCs were exposed to neutralizing antibodies against tumor necrosis factor receptors TNF-RI and TNF-RII or nonrelevant isotype-matched control antibodies (Control Ab) 1 hour prior to stimulation with TNF-α (50 ng/ml), and in the course of 24 hours of stimulation by the cytokine. Control, cells stimulated with vehicle. Expression of CCL2 was determined by ELISA, in the linear range of absorbance. The findings are representatives of at least n = 3 independent experiments that have shown similar results.