Fig. 4

Validation of PKIS hit compounds in cell lines and primary human macrophages. (a, b) The efficacy of the hit compounds was validated in CFU assays using lysates from Stm-infected HeLa cells (a) and Mtb-infected MelJuSo cells (b). The bacterial burden is expressed as a percentage of CFUs compared to the DMSO control. (c, d) Compound safety was assessed using an LDH-release assay with supernatant from Stm-infected HeLa cells (c) and Mtb-infected MelJuSo cells (d), with cell viability expressed as a percentage of the DMSO control and with 1% Triton X-100-treated cells corresponding to 0%. (e, f) To assess whether hit compounds act as antibiotics or host-directed therapeutics, direct antimicrobial effects were evaluated in cell-free cultures of Stm (e) and Mtb (f). The turbidity of the bacterial suspensions, as measured by absorbance at OD600, is given as a percentage of the DMSO control. (g) The efficacy of the hit compounds was validated in CFU assays using lysates from Stm-infected M1 (black circles, grey bars) and M2 (white circles, open bars) primary human macrophages. (h) An LDH-release assay was performed using supernatant from Stm-infected macrophages. (i) The efficacy of the hit compounds was validated in CFU assays using lysates from Mtb-infected M1 (black circles) and M2 (white circles) primary human macrophages. (j) An LDH-release assay was performed using supernatant from Mtb-infected macrophages.