Compound structures. Compounds (A–J) were identified in the original high-throughput screen. CCG-2979 was chosen as the lead compound (details in the text). CCG-102487 was identified as a commercially available analog of CCG-2979.

Effect of CCG-2979 and CCG-102487 on SK expression and GAS growth. (A) Effects of CCG-2979 and CCG-102487 on the production of SK activity. Normalized SK activity of GAS treated with CCG-2979 or CCG-102487 at concentrations from 5 to 100 μM (SK activity of culture media was divided by OD₆₀₀ and then normalized to the value for DMSO-treated GAS, which was defined as 100%). The value was presented as mean ± SE for a total of 18 samples (pooled from six independent experiments with triplicates). (B) GAS growth as measured by OD₆₀₀ of an overnight culture in the presence of CCG-2979 at concentrations of 5–100 μM normalized to the OD₆₀₀ of control GAS grown in DMSO vehicle alone. The value was presented as mean ± SE for a total of 18 samples (pooled from six independent experiments with triplicates). (C) Growth curves for UMAA2616 in the presence of 0.1% DMSO, 50 μM CCG-2979, or 50 μM CCG-102487. Mean and SE for a total of six samples (two independent experiments with triplicates) are presented for each time point. (D) Decreased GAS resistance to phagocytosis in the presence of CCG-2979 or CCG-102487. Each point represents an individual experiment.

The effect of CCG-102487 on the GAS gene expression program. Growth curves for MGAS2221 in the presence of CCG-102487 (46.7 μM) or DMSO vehicle alone as determined by OD (A) or cfu (B). (C) Graphic summary of gene expression changes. Genes down-regulated on treatment with CCG-102487 are indicated in green, and genes up-regulated on treatment with CCG-102487 are indicated in red. Genes of known homology or function were included. Complete data for gene expression changes are summarized in Table S1.

Treatment with CCG-2979 improves survival in an in vivo mouse model for GAS infection. (A) Effect on survival of CCG-2979 [12.7 nmol (5 μg) per mouse] injected daily for 5 d beginning 24 h after infection of PLGTg+ mice with UMAA2616. Data were pooled from four independent experiments (with GAS inoculation of 8.3, 2.8, 3.6, or 4.0 × 10⁵ cfu/mouse, respectively). A total of 27 mice were represented in the control group treated with vehicle alone (solid line), and 27 mice were represented in the CCG-2979–treated group (dashed line). (B) The same model as in A except that CCG-2979 was injected at a dose of 101.4 nmol (40 μg) per mouse per day for 4 d. Data were pooled from three independent experiments (with GAS inoculation of 4.22, 3.16, or 1.24 × 10⁶ cfu/mouse, respectively). A total of 22 mice were represented in the control group (solid line), and 19 mice were represented in the CCG-2979–treated group (dashed line). (C) Pooled data from A and B, including all data for CCG-2979. (D) Pooled data for both compounds. CCG-102487 [93.3 nmol (40 μg) per mouse] was injected daily for 4 d beginning 24 h after infection of PLGTg+ mice with UMAA2616. Data for CCG-102487 (dotted line) are from one experiment (total of 10 mice with GAS inoculation of 4.22 × 10⁶ cfu/mouse). P values were calculated with all pairwise multiple comparison procedures (Bonferroni method).