JTZ-951 (enarodustat), a hypoxia-inducible factor prolyl hydroxylase inhibitor, improves iron utilization and anemia of inflammation: Comparative study against recombinant erythropoietin in rat.

Anemia with inflammation-induced defective iron utilization is a pathological condition observed in patients suffering from chronic kidney disease (CKD) or chronic inflammatory disease. There is no reasonable treatment for these conditions, because the effects of erythropoiesis stimulating agents (ESAs) or iron supplementation in the treatment of anemia are insufficient. JTZ-951 (enarodustat) has been characterized as a novel, orally bioavailable inhibitor of hypoxia-inducible factor prolyl hydroxylase (HIF-PH), and has been developed as a novel therapeutic agent for anemia with CKD. In this study, the effects of JTZ-951 on iron utilization during erythropoiesis and on anemia of inflammation were compared with those of recombinant human erythropoietin (rHuEPO) using normal rat and rat model of anemia of inflammation. In normal rats, under conditions in which JTZ-951 and rHuEPO showed similar erythropoietic effect, repeated doses of JTZ-951 induced erythropoiesis while retaining the hemoglobin content in red blood cells, while administration of rHuEPO resulted in decrease in some erythrocyte-related parameters. As for iron-related parameters during erythropoiesis, JTZ-951 exhibited more efficient iron utilization compared to rHuEPO. A single dose of JTZ-951 resulted in decrease in hepcidin expression observed within 24 h after administration, but a single dose of rHuEPO did not. In a rat model of anemia of inflammation (also known as a model with functional iron-deficiency), JTZ-951 showed erythropoietic effect, in contrast with rHuEPO. These results suggest that, unlike rHuEPO, JTZ-951 stimulates erythropoiesis by increasing iron utilization, and improves anemia of inflammation.

JTZ-951, an HIF prolyl hydroxylase inhibitor, suppresses renal interstitial fibroblast transformation and expression of fibrosis-related factors.

Some preceding studies have provided evidence that hypoxia-inducible factor (HIF)-prolyl hydroxylase (PH) inhibitors have therapeutic potential against tubular interstitial fibrosis (TIF). Recently, transformation of renal interstitial fibroblasts (RIFs) into α-smooth muscle actin-positive myofibroblasts with loss of their hypoxia-inducible erythropoietin (EPO) expression has been hypothesized as the central mechanism responsible for TIF with renal anemia (the RIF hypothesis). These reports have suggested that HIF-PH inhibitors may suppress TIF via suppressing transformation of RIFs. However, the direct effect of HIF-PH inhibitors on transformation of RIFs has not been demonstrated because there has been no appropriate assay system. Here, we established a novel in vitro model of the transformation of RIFs. This model expresses key phenotypic changes such as transformation of RIFs accompanied by loss of their hypoxia-inducible EPO expression, as proposed by the RIF hypothesis. Using this model, we demonstrated that JTZ-951, a newly developed HIF-PH inhibitor, stabilized HIF protein in RIFs, suppressed transformation of RIFs, and maintained their hypoxia-inducible EPO expression. JTZ-951 also suppressed the expression of FGF2, FGF7, and FGF18, which are upregulated during transformation of RIFs. Furthermore, expression of Fgf2, Fgf7, and Fgf18 was correlated with TIF in an animal model of TIF. We also demonstrated that not only FGF2, which is a well-known growth-promoting factor, but also FGF18 promoted proliferation of RIFs. These data suggest that JTZ-951 has therapeutic potential against TIF with renal anemia. Furthermore, FGF2, FGF7, and FGF18, which faithfully reflect the anti-TIF effects of JTZ-951, have potential as TIF biomarkers.

JTZ-951 (enarodustat), a hypoxia-inducibe factor prolyl hydroxylase inhibitor, stabilizes HIF-α protein and induces erythropoiesis without effects on the function of vascular endothelial growth factor.

JTZ-951 (enarodustat) is an oral hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor. JTZ-951 has inhibitory activities on human HIF-prolyl hydroxylase 1-3, but not on various receptors or enzymes. In Hep3B cells, JTZ-951 increased HIF-1α and HIF-2α protein levels, erythropoietin (EPO) mRNA levels, and EPO production. In normal rats, after a single oral dose of JTZ-951, the hepatic and renal EPO mRNA levels and plasma EPO concentrations were also increased. In 5/6-nephrectomized rats, repeated oral doses of JTZ-951 once daily or intermittent dosing showed the erythropoiesis stimulating effect. The administration of JTZ-951 at a high dose increased plasma vascular endothelial growth factor (VEGF) levels; however, retinal VEGF mRNA levels and the retinal vascular permeability were not changed. Finally, we evaluated the effect of JTZ-951 in a colorectal cancer cell-inoculated mouse model. Although JTZ-951 at a high dose increased the plasma VEGF, it had no effect on tumor growth. In summary, JTZ-951 induces erythropoiesis without affecting VEGF function. Therefore, it is expected that JTZ-951 will be a new oral candidate that increases and maintains hemoglobin concentrations in renal anemia patients.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks antigen-induced allergic reactions in rats.

Conventional clinical treatments for allergy management remain suboptimal; new, orally available medications that improve a wide range of allergic signs have been desired. We previously demonstrated that JTE-852, a novel spleen tyrosine kinase inhibitor, potently and simultaneously suppresses secretion of granule contents, arachidonate metabolites, and cytokines from mast cells stimulated by immunoglobulin E-crosslinking. In the present study, we investigated the effects of JTE-852 in four rat models (sneezing, rhinorrhea, airway constriction, and airway inflammation) as representatives of allergy models. Rats were sensitized and challenged with antigen. Allergic reactions developed after challenge were detected. JTE-852 and current anti-allergic drugs (ketotifen, pranlukast, and prednisolone) were administered orally before challenge. JTE-852 showed significant blocking effects on antigen-induced allergic reactions in all models, indicating that JTE-852 in oral dosage form would improve a wide range of allergic signs. The current anti-allergic drugs, on the other hand, failed to display significant suppression in several models. Because JTE-852 suppresses the secretion of all three groups of allergic mediators from mast cells, it would be capable of targeting signs that current drugs cannot sufficiently relieve. We anticipate JTE-852 to be a promising new anti-allergic drug that is potentially more effective than conventional drugs.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks immunoglobulin G-mediated cellular responses and autoimmune reactions in vivo.

AIMS: Immune and inflammatory responses mediated by immunoglobulin (Ig) G are largely responsible for the pathogenesis of autoimmune diseases. Spleen tyrosine kinase (Syk) plays a pivotal role in the IgG-mediated responses; therefore, Syk has emerged as a new therapeutic target for the treatment of autoimmune diseases. In this study, we investigated the inhibitory actions of JTE-852, a novel Syk inhibitor, on IgG-mediated cellular responses and autoimmune reactions in vivo. MAIN METHODS: We examined mediator secretion from human monocytes. We also conducted rat models of reversed cutaneous anaphylaxis (RCA) and reversed passive Arthus (RPA), which are classified as type II and type III hypersensitivities, respectively. In a rat collagen-induced arthritis (CIA) model, JTE-852 or methotrexate was administered preventively (before the onset of arthritis) or therapeutically (after the onset of arthritis). KEY FINDINGS: JTE-852 blocked secretion of reactive oxygen species and tumor necrosis factor-α from monocytes stimulated by IgG crosslinking. In the RCA and RPA models, JTE-852 also suppressed edema and dye leakage, respectively. In the CIA model, JTE-852 showed both preventive and therapeutic effects against joint swelling and bone erosion; on the other hand, methotrexate did not show the therapeutic effect. SIGNIFICANCE: JTE-852 attenuates IgG-mediated responses and signs in animal model of autoimmune diseases. JTE-852 is thus a promising candidate for a novel, orally available drug for the treatment of autoimmune diseases.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks mediator secretion from mast cells with immunoglobulin E crosslinking.

Mast cells stimulated by immunoglobulin E (IgE)-crosslinking secrete mediators, which are mainly categorized into three groups: granule contents, arachidonate metabolites, and cytokines. These mediators play important roles in pathogenesis of allergic diseases; indeed, some conventional drugs which target the mediators are used in clinical practices. However, these drugs are not yet sufficient enough in their efficacy. That is because most of them are blockers of single mediators and are unable to prevent simultaneously various reactions caused by the three group mediators. Spleen tyrosine kinase (Syk) is a non-receptor protein tyrosine kinase. In mast cells, Syk locates at almost top of the signal cascades induced by IgE-crosslinking and plays pivotal roles in secretion of the three groups of mediators. Therefore, inhibition of Syk would suppress the secretion of all the mediators from mast cells and be a promising-treatment strategy for allergic diseases. In the present study, we characterized pharmacological profiles of JTE-852, which was identified as a novel Syk inhibitor. JTE-852 inhibited kinase activity of Syk in an adenosine 5'-triphosphate (ATP)-competitive fashion. JTE-852 also blocked the secretion of granule contents, arachidonate metabolites, and cytokines from mast cells stimulated by IgE-crosslinking, with similar potencies. The results suggest that JTE-852 is supposed to prevent various allergic reactions caused by the three group mediators in vivo. In fact, oral gavage of JTE-852 attenuated an allergic reaction mediated by histamine, which is a representative of the three groups of mediators. JTE-852 is expected to be a novel, highly-efficacious, and orally available anti-allergic drug.