Fig. 2
CXCL12-LD is a balanced partial agonist. (A) cAMP levels in THP-1 cells stimulated with 10 mM IBMX and 1 µM forskolin followed by treatment with various compounds measured by a competitive enzyme immunoassay. All significance values are in relation to FSK/IBMX by two-way ANOVA with Dunnett’s multiple comparison test. (B, C) Calcium flux in THP-1 and U937 cells treated with either CXCL12-WT or CXCL12-LD. n = 3. (D) AML cells were pre-treated with pertussis toxin prior to treatment with CXCL12 variants. All pertussis toxin pre-treated values are significantly different by Student’s t-test when compared to the same form of CXCL12 without pertussis toxin. (E) The log(Emax/EC50) of the CXCL12 variants from net BRET in HEK293-CXCR4-Luc cells transfected with β-arrestin or Gαi Venus transducer. n = 6, EC50 values calculated from non-linear curve fit, all r2 values > 0.82. (F) Bias factors for CXCL12-WT, -LM, and -LD at all timepoints tested from HEK293 BRET studies calculated using the calculator found on the Biased Signaling Atlas29. A bias factor > 5 is indicative of biased agonism.
