Thus growth factor- or FLT3-dependent signaling appears to inhibit Hepcidin promoter activity and to impair the stimulatory effects of AG1296 and GTP 14564, but we did not observe a phenomenon that was limited to one particular
growth factor or ligand. We had hypothesized that the Hepcidin stimulatory molecules identified in the screen would increase phosphorylation of Smad1,5, and 8 and/or phosphorylation of Stat3. To evaluate this hypothesis, we performed Western blots to evaluate the ratio of P-Smad1,5,8 to Smad1 ( Fig. 4A) and P-Stat3 to Stat3 ( Fig. 4B). As expected, BMP6 treatment increased selleck chemical the intensity of P-Smad1,5,8 relative to Smad1 after 1 h of treatment, however, none of the small molecules significantly increased the intensity of P-Smad1,5,8 relative to Smad1, as assessed by densitometry. Furthermore, in the one hour time frame, neither IL-6 nor any of the small molecules tested increased the intensity of P-Stat3 relative to Stat3. WP1066, a known inhibitor of Jak2 and Stat3 phosphorylation  for Jak/Stat signaling, did not decrease P-Stat3 to Stat3, however WP1066 is reported to be more effective Selleckchem PD-1/PD-L1 inhibitor 2 after 24–48 h of incubation . After 24 h of
treatment, we observed a significant increase in Stat3 protein levels relative to DMSO-treated controls in the hepatocytes treated with lansoprazole or vorinostat (2.34 ± 0.96, P = 0.047 and 1.88 ± 0.43, P = 0.03, respectively, Supplementary Sitaxentan Fig. 1), but no significant change in phosphorylation of Stat3 relative to Stat3 levels. In this study, we have demonstrated a high throughput screening method to identify small molecules that regulate Hepcidin gene expression using a Hepcidin-luciferase
reporter cell line. Our study was the first large-scale screen for small molecules upregulating Hepcidin transcript levels. Using a screening approach that includes toxicity evaluation, we have identified the largest number of non-toxic small molecules that stimulate Hepcidin, which will facilitate future preclinical studies in iron overload syndromes. Several of the Hepcidin stimulating agents that we identified are drugs that are orally bioavailable or have been approved by the United States Food and Drug Administration (FDA) for other indications. These factors will facilitate their testing in preclinical models. The FDA-approved drugs that we identified include amlexanox, lansoprazole, leflunomide, vorinostat, and phenazopyridine, while pterostilbene and isoflavone are already commercially available as nutritional supplements. Small scale screening efforts previously identified genistein  and three kinase inhibitors  as small molecules that stimulate Hepcidin expression. Peptide analogs of hepcidin, minihepcidins, have also been injected into Hepcidin-deficient mice to prevent iron overload , but are not orally available.