Membranes were probed with the EP2 and EP4 receptor polyclonal antibodies (Cayman Chemicals), followed by HRP-conjugated anti-rabbit secondary antibody and Pierce ECL detection reagents. Quantification of each receptor was normalized to the housekeeping protein α-tubulin. Phorbol-12-myristate-13-acetate-activated THP-1 cells were stored in TRIzol Reagent (Invitrogen) at −80°C until RNA was extracted and cDNA was generated per our previously Roscovitine nmr published protocol.[6] Human primers and probes were designed using the Roche Universal Probe Library Assay Design Center.

Primers were generated by Integrated DNA Technology and all probes were from Roche (Basel, Switzerland). Primers used are as follows: human EP2 forward 5′-GGA GGA GAC GGA CCA CCT-3′, EP2 reverse 5′- GTT TCA TTC ATA TAT GCA AAA ATC GT-3′ (Universal Probe Library #2); and human EP4 forward 5′-CTC CCT GGT GGT screening assay GCT CAT-3′, EP4 reverse 5′-GGC TGA TAT AAC TGG TTG ACG A-3′ (Universal Probe Library # 58). The Universal Probe Library Gene Assay (Roche) for human GAPDH was also used (Universal Probe Library # 60).

Samples were run on the Light Cycler 480 (Roche) with the following conditions: 95°C, 10 min (pre-incubation); 95°C 10 s; 60°C, 30 s; 72°C, 1 s (amplification, 45 cycles); 95°C, 10 s; 50°C, 30 s; 70°C, 5 min (melting curve); 40°C, 30 s (cooling). Analysis was performed using the Roche software, and expression of each gene was referenced to the expression of the housekeeping gene GAPDH. Results were calculated buy Decitabine using the 2−ΔΔCT method.[26] Statistical analyses were carried out using GraphPad Prism 5.0 software for Windows (GraphPad Software, San Diego, CA, USA). Unless otherwise stated, experimental data are presented as a percentage

of the untreated control group (set at 100%). Error bars represent the standard error of the mean (S.E.M.). All analyses were conducted on raw data prior to normalizing to the untreated control. Where appropriate, mean values were compared using a paired Student’s t-test or a repeated measured analysis of variance (anova). A Dunnett’s post-test was conducted for comparisons with the control value, or a Tukey’s test was performed for multiple comparisons. Differences were considered significant if P ≤ 0.05. Experiments were performed on at least three separate occasions. The PGE1 analog misoprostol, which binds to the same four EP receptors as does PGE2,[27] was previously found to inhibit the phagocytosis of vegetative C. sordellii by rodent macrophages.[7] The capacity for authentic PGE2 to regulate human phagocyte–clostridial interactions has not been examined. Human THP-1 macrophage-like cells were used to model the regulation of phagocytosis of unopsonized, vegetative C. sordellii. Although C.