Prolyl Hydroxylase Inhibitor Research Articles

Effects of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors on Copper Metabolism and Association with Organ Damage in CKD

Effects of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors on Copper Metabolism and Association with Organ Damage in CKD

Efficacy and Safety of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors (HIF-PHIs) in Patients with CKD: Metanalysis of Phase 3 Randomized Controlled Trials

Efficacy and Safety of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors (HIF-PHIs) in Patients with CKD: Metanalysis of Phase 3 Randomized Controlled Trials

Long-Term Safety of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors in CKD: A Systematic Review and Meta-Analysis of Randomized Trials

Long-Term Safety of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors in CKD: A Systematic Review and Meta-Analysis of Randomized Trials

DMOG protects against murine IL-33-induced pulmonary type 2 inflammation through HIF-1 pathway in innate lymphoid cells

One of the traditional methods of treating allergy is to avoid the allergen, protocol that has long been used in high altitude clinics. It has been hypothesized that the therapeutic effect of high altitude on allergy is due to allergen avoidance, exposure to sunlight and reduced stress. However, the contribution of environmental elements like low oxygen pressure and hypoxia remains underexplored. In this study, we examined the role of hypoxia in the development of type 2 lung inflammation. Mice were administered with papain or recombinant IL-33 intra-nasally to induce type 2 lung inflammation. Some of them were treated additionally with the prolyl hydroxylase (PHD) inhibitor DMOG, which mimics hypoxia. DMOG treatment exhibited an inhibitory effect on the lung inflammation induced by papain or IL-33, operating in a manner independent of T and B cells. The anti-inflammatory effect of DMOG was accompanied by a downregulation of IL-5 and IL-13 in innate lymphoid cells (ILCs), which was abolished in HIF-1α deficient mice. Collectively, our findings suggest that DMOG's modulatory effect on IL-5 and IL-13 operates through the HIF-1 pathway, resulting in a reduction in type 2 lung inflammation. These findings underscore the role of the PHD-HIF pathway in IL-5 and IL-13 expression in lung ILCs and pharmacological inhibition of PHD might be a novel therapeutic candidate for type 2 lung inflammation.

Antioxidants stimulate BACH1-dependent tumor angiogenesis.

Lung cancer progression relies on angiogenesis, which is a response to hypoxia typically coordinated by hypoxia-inducible transcription factors (HIFs), but growing evidence indicates that transcriptional programs beyond HIFs control tumor angiogenesis. Here, we show that the redox-sensitive transcription factor BTB and CNC homology 1 (BACH1) controls the transcription of a broad range of angiogenesis genes. BACH1 is stabilized by lowering ROS levels; consequently, angiogenesis gene expression in lung cancer cells, tumor organoids, and xenograft tumors increased substantially following administration of vitamins C and E and N-acetylcysteine in a BACH1-dependent fashion under normoxia. Moreover, angiogenesis gene expression increased in endogenous BACH1-overexpressing cells and decreased in BACH1-knockout cells in the absence of antioxidants. BACH1 levels also increased upon hypoxia and following administration of prolyl hydroxylase inhibitors in both HIF1A-knockout and WT cells. BACH1 was found to be a transcriptional target of HIF1α, but BACH1's ability to stimulate angiogenesis gene expression was HIF1α independent. Antioxidants increased tumor vascularity in vivo in a BACH1-dependent fashion, and overexpressing BACH1 rendered tumors sensitive to antiangiogenesis therapy. BACH1 expression in tumor sections from patients with lung cancer correlated with angiogenesis gene and protein expression. We conclude that BACH1 is an oxygen- and redox-sensitive angiogenesis transcription factor.

In silico and in vitro human metabolism of IOX2, a performance-enhancing doping agent

IOX2 is a potent inhibitor of prolyl hydroxylase 2, a key enzyme in the regulation of hypoxia-inducible factor (HIF) and oxygen homeostasis. As such, it can be used to enhance athletic performance and is currently banned by the World Anti-Doping Agency (WADA). Detection of metabolites is critical to demonstrate drug use in doping. However, there is currently little data on IOX2 human metabolism. Our aim was to identify relevant biomarkers of IOX2 use in humans. For this purpose, IOX2 was incubated with 10-donor-pooled human hepatocytes for 3 h, incubates were analyzed by liquid chromatography-high-resolution tandem mass spectrometry (LC–HRMS/MS), and LC–HRMS/MS data were screened with Compound Discoverer (Thermo Scientific) for a comprehensive identification of IOX2 metabolites. Additionally, IOX2 human metabolites were predicted with GLORYx open-access software (University of Hamburg, Germany) to assist in the LC–HRMS/MS analysis and data mining. Thirteen metabolites were identified, oxidation at the quinolinyl group, O-glucuronidation, and combinations being predominant biotransformations. The results were consistent with previous animal studies and a single case of oral microdose administration. We suggest hydroxyquinolinyl-IOX2 as major biomarker of IOX2 use in biological samples, glucuronide hydrolysis being critical to increase IOX2 and hydroxyquinolinyl-IOX2 detectability in urine.

Fragment-Based NMR Screening of the BPTF PHD Finger Methyl Lysine Reader Leads to the First Small-Molecule Inhibitors.

Methyl lysine readers, specifically PHD fingers, are emerging epigenetic targets in human diseases. For example, several PHD finger fusions are implicated in clinical cases of acute myeloid leukemia, highlighting the potential for PHD inhibitors in disease regulation. However, limited chemical matter targeting PHD fingers exists. Here we report the first fragment-based screen against the BPTF PHD to identify several of the first reported BPTF PHD-targeting small-molecule ligands. We used ligand-observed NMR to first screen a fragment library, followed by biophysical validation to prioritize two scaffolds, pyrrolidine- and pyridazine-containing fragments. Structural predictions show that these respective scaffolds may engage two distinct subpockets on the protein. The demonstrated ligandability of the BPTF PHD supports the future development of methyl lysine reader chemical probes to study their oncogenic functions.

Roxadustat treatment for erythropoiesis-stimulating agent-hyporesponsive anemia in maintenance hemodialysis patients.

Hyporesponsiveness to erythropoiesis-stimulating agents (ESAs) is a prevalent problem affecting hemodialysis (HD) patients. Roxadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis and regulates iron metabolism. We explored the ability of roxadustat to increase the hemoglobin (Hb) concentration in ESA-hyporesponsive patients undergoing HD and assessed its effect on iron metabolism and inflammation. This prospective study included 30 patients with ESA-hyporesponsive anemia who had been undergoing stable dialysis. All patients received roxadustat three times per week for 24 weeks. The primary endpoint was the mean change in Hb from baseline to the average level over weeks 20 to 24. Iron metabolism markers, C-reactive protein, interleukin (IL)-6, and safety were also assessed. At week 24, roxadustat treatment resulted in a 2.5 ± 1.3 g/dL increase in the Hb level. In total, 28 of 30 patients (93.3%) had an Hb level increase of more than 1.0 g/dL from baseline. Seventeen patients (56.7%) met the endpoint, with a mean Hb level of at least 10.0 g/dL. Iron metabolism and IL-6 levels were also improved. Oral roxadustat is effective for ESA-hyporesponsive anemia in maintenance HD patients and may also improve iron metabolism and IL-6 levels.

Development of a health economic model to evaluate the cost-effectiveness of roxadustat in treating anemia associated with non-dialysis-dependent chronic kidney disease

BackgroundTreatment for anemia of chronic kidney disease (CKD) largely consists of erythropoiesis-stimulating agents (ESAs) with iron supplementation. Although ESAs are well-established and efficacious, their use has been associated with considerable economic and humanistic burdens. Roxadustat, an oral medication, is a hypoxia-inducible factor prolyl hydroxylase inhibitor that targets multiple causes of CKD and has a similar efficacy and safety profile to ESAs. The cost-effectiveness of this treatment, however, has yet to be investigated.ObjectiveThe study objective was to develop a health economic model to evaluate the cost-effectiveness of roxadustat compared with ESAs for treating anemia of non-dialysis-dependent (NDD) CKD.MethodsA cohort-based model was developed for a hypothetical cohort of 1,000 patients with anemia of NDD CKD, incorporating eight health states, representing the hemoglobin level of each patient. The model was informed by individual patient-level data from the roxadustat global phase 3 clinical trial program. Total and incremental costs as well as quality-adjusted life-years (QALYs) associated with roxadustat versus ESAs were estimated from the perspective of the UK National Health Service. Sensitivity analyses were performed to assess the robustness of the model. Analyses exploring alternative scenarios were also conducted.ResultsOn a per-person basis, over 1,000 simulations, roxadustat was found to be on average less costly (−£32) and more effective (+0.01 QALYs) than ESAs, with a dominant incremental cost-effectiveness ratio. The probability of cost-effectiveness at a £20,000 per QALY willingness-to-pay threshold from the UK perspective was 67%.ConclusionThe model developed may be a useful instrument that, alongside expert clinical opinion, can inform clinical and policy decision-making regarding treatment of anemia of NDD CKD. The model highlights the cost-effectiveness of roxadustat, as well as its potential to have a meaningful impact in reducing the burden of anemia of NDD CKD.

Use of molidustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, in chronic kidney disease-associated anemia in cats.

Erythropoietic effects of molidustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor, were previously demonstrated in healthy cats. To evaluate the safety and erythropoietic effects of daily PO administration of molidustat in anemic cats with chronic kidney disease (CKD). Twenty-one client-owned CKD cats (4-17 years old) with anemia. Multicenter field study; randomized, masked, and placebo-controlled. Cats were treated PO once daily for 28 days with suspensions of control product (CP; n = 6) or 5 mg/kg of molidustat (n = 15). Hematocrit (HCT) was evaluated at weekly intervals. Individual cat treatment success was defined as a ≥4% point increase in HCT compared to baseline. Control group mean HCT remained low throughout the study (20.1%-23.4%). Mean HCT of molidustat-treated cats increased weekly, and a significant increase compared to baseline (23.6%) was first observed on Day 21 (27.3%; P < .001; 95% confidence interval [CI], 1.69-5.67). Compared to CP group, mean HCT was significantly higher on Day 21 (27.3% vs 20.1%; P < .001; 95% CI, 2.91-10.75) but not significantly higher on Day 28 (27.8% vs 23.4%; P = .06; 95% CI, -0.23 to 9.88). The number of individual treatment successes on Day 28 was higher among remaining molidustat-treated cats (7/14) compared to remaining control cats (1/5), but there was no significant difference between groups. Daily PO molidustat administration may stimulate a clinically relevant erythropoietic response in anemic cats with CKD. This HIF-PH inhibitor may be an alternative for managing anemia in cats compared to recombinant EPO treatment.

The neuroprotective effects of FG-4592, a hypoxia-inducible factor-prolyl hydroxylase inhibitor, against oxidative stress induced by alpha-synuclein in N2a cells

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra. The pathological hallmark of PD is the appearance of intraneuronal cytoplasmic α-synuclein (α-Syn) aggregation, called Lewy bodies. α-Syn aggregation is deeply involved in the pathogenesis of PD. Oxidative stress is also associated with the progression of PD. In the present study, to investigate whether a hypoxia-inducible factor (HIF)-prolyl hydroxylase (PH) inhibitor, FG-4592 (also called roxadustat), has neuroprotective effects against α-Syn-induced neurotoxicity, we employed a novel α-Syn stably expressing cell line (named α-Syn-N2a cells) utilizing a piggyBac transposon system. In α-Syn-N2a cells, oxidative stress and cell death were induced by α-Syn, and FG-4592 showed significant protection against this neurotoxicity. However, FG-4592 did not affect α-Syn protein levels. FG-4592 triggered heme oxygenase-1 (HO-1) expression downstream of HIF-1α in a concentration-dependent manner. In addition, FG-4592 decreased the production of reactive oxygen species possibly via the activation of HO-1 and subsequently suppressed α-Syn-induced neurotoxicity. Moreover, FG-4592 regulated mitochondrial biogenesis and respiration via the induction of the peroxisome proliferator-activated receptor-γ coactivator-1α. As FG-4592 has various neuroprotective effects against α-Syn and is involved in drug repositioning, it may have novel therapeutic potential for PD.

The Role of Hypoxia on the Trimethylation of H3K27 in Podocytes.

Epigenetic alterations contribute to the pathogenesis of chronic diseases such as diabetes mellitus. Previous studies of our group showed that diabetic conditions reduce the trimethylation of H3K27 in podocytes in a NIPP1- (nuclear inhibitor of protein phosphatase 1) and EZH2- (enhancer of zeste homolog 2) dependent manner. It has been previously reported that in differentiated podocytes, hypoxia decreases the expression of slit diaphragm proteins and promotes foot process effacement, thereby contributing to the progression of renal disease. The exact mechanisms are, however, not completely understood. The aim of this study was to analyze the role of hypoxia and HIFs (hypoxia-inducible factor) on epigenetic changes in podocytes affecting NIPP1, EZH2 and H3K27me3, in vitro and in vivo. In vivo studies were performed with mice exposed to 10% systemic hypoxia for 3 days or injected with 3,4-DHB (dihydroxybenzoate), a PHD (prolyl hydroxylase) inhibitor, 24 h prior analyses. Immunodetection of H3K27me3, NIPP1 and EZH2 in glomerular podocytes revealed, to the best of our knowledge for the first time, that hypoxic conditions and pharmacological HIFs activation significantly reduce the expression of NIPP1 and EZH2 and diminish H3K27 trimethylation. These findings are also supported by in vitro studies using murine-differentiated podocytes.

A review on analytical profile for newly FDA approved drugs in 2023

In 2023, the field of pharmaceuticals witnessed the approval of several novel drugs by the United States Food and Drug Administration (USFDA). These drugs represent significant advancements in the treatment of various medical conditions and have undergone rigorous evaluation to ensure their safety and efficacy. To support their development and subsequent quality control, a variety of analytical methods have been employed. This review highlights the analytical methods employed for the evaluation and quality control of FDA approved drugs. These methods encompass a range of techniques that enable the characterization, quantification, and quality assessment of pharmaceutical compounds. Commonly employed analytical techniques include chromatographic methods such as high-performance liquid chromatography (HPLC), Liquid Chromatography-Mass Spectrometry (LC-MS), Ultra-Performance Liquid Chromatography (UPLC), Ultra-high-performance liquid chromatography (UHPLC), Ultra- performance liquid chromatography-Mass Spectrometry (UPLC-MS). The Approved Drugs are Bexagliflozin (Sodium-glucose Cotransporter 2 Inhibitor (SGLT2)), Daprodustat (Hypoxia-inducible factor prolyl hydroxylase inhibitor), Valmanasealfa-tycv (Recombinant human lysosomal alpha-mannosidase), Rezafungin(Echinocandin antifungal drug), Sparsentan (Dual endothelin and angiotensin II receptor antagonist), Nirmatrelvir (Anti-viral), Ritonavir (Protease Inhibitors). Overall, the approval of FDA drugs in 2023 relied on the utilization of diverse and robust analytical methods. These methods facilitated the rigorous assessment of drug quality, safety, and efficacy, ensuring that patients receive reliable and effective treatments. The continuous advancement of analytical techniques will further contribute to the development and evaluation of innovative pharmaceuticals in the future.

The anaemia treatment journey of CKD patients: from epoetins to hypoxia-inducible factor-prolyl hydroxylase inhibitors.

The discovery and development of erythropoiesis-stimulating agents was a journey lasting more than a century, leading to the cloning and approval of recombinant human erythropoietin (rHuEpo). This was an impressive clinical advance, providing the possibility of correcting the symptoms associated with anaemia in chronic kidney disease. Associated iron use was needed to produce new haemoglobin-containing blood red cells. Partial anaemia correction became the standard of care since trials aiming for near-normal haemoglobin levels showed a higher risk of adverse cardiovascular events. Hoping to reduce the cardiovascular risks, a new category of drugs was developed and tested. Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) are small molecules than can be formulated into orally active pills. They simulate reduced tissue oxygen pressure, thus stimulating the production of endogenous erythropoietin (Epo) by the kidneys and liver. Clinical trials with these compounds demonstrated that HIF-PHIs are at least as effective as rHuEpo in treating or correcting anaemia in non-dialysis and dialysis patients. Trials with HIF-PHIs did not demonstrate superiority in safety outcomes and in some trials, outcomes were worse. There was also a focus on oral delivery, a possible beneficial iron-sparing effect and the ability to overcome Epo resistance in inflamed patients. A negative effect is possible iron depletion, which may explain adverse outcomes.

Changes in Metabolomic Profiles Induced by Switching from an Erythropoiesis-Stimulating Agent to a Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor in Hemodialysis Patients: A Pilot Study.

Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) are a new class of medications for managing renal anemia in patients with chronic kidney disease (CKD). In addition to their erythropoietic activity, HIF-PHIs exhibit multifaceted effects on iron and glucose metabolism, mitochondrial metabolism, and angiogenesis through the regulation of a wide range of HIF-responsive gene expressions. However, the systemic biological effects of HIF-PHIs in CKD patients have not been fully explored. In this prospective, single-center study, we comprehensively investigated changes in plasma metabolomic profiles following the switch from an erythropoiesis-stimulating agent (ESA) to an HIF-PHI, daprodustat, in 10 maintenance hemodialysis patients. Plasma metabolites were measured before and three months after the switch from an ESA to an HIF-PHI. Among 106 individual markers detected in plasma, significant changes were found in four compounds (erythrulose, n-butyrylglycine, threonine, and leucine), and notable but non-significant changes were found in another five compounds (inositol, phosphoric acid, lyxose, arabinose, and hydroxylamine). Pathway analysis indicated decreased levels of plasma metabolites, particularly those involved in phosphatidylinositol signaling, ascorbate and aldarate metabolism, and inositol phosphate metabolism. Our results provide detailed insights into the systemic biological effects of HIF-PHIs in hemodialysis patients and are expected to contribute to an evaluation of the potential side effects that may result from long-term use of this class of drugs.

Precision Medicine in Erythropoietin Deficiency and Treatment Resistance: A Novel Approach to Management of Anaemia in Chronic Kidney Disease.

The study of anaemia is a well-developed discipline where the concepts of precision medicine have, in part, been researched extensively. This review discusses the treatment of erythropoietin (EPO) deficiency anaemia and resistance in cases of chronic kidney disease (CKD). Traditionally, erythropoietin-stimulating agents (ESAs) and iron supplementation have been used to manage anaemia in cases of CKD. However, these treatments pose potential risks, including cardiovascular and thromboembolic events. Newer treatments have emerged to address these risks, such as slow-release and low-dosage intravenous iron, oral iron supplementation, and erythropoietin-iron combination therapy. Another novel approach is the use of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs). This review highlights the need for precision medicine targeting the genetic components of EPO deficiency anaemia in CKD and discusses individual variability in genes such as the erythropoietin gene (EPO), the interleukin-β gene (IL-β), and the hypoxia-inducible factor gene (HIF). Pharmacogenetic testing aims to provide targeted therapies and interventions that are tailored to the specific characteristics of an individual, thus optimising treatment outcomes and minimising resistance and adverse effects. This article concludes by suggesting that receptor modification has the potential to revolutionise the treatment outcomes of patients with erythropoietin deficiency anaemia through the integration of the mentioned approach.

Effects of pharmacological delay with roxadustat on multi-territory perforator flap survival in rats.

Roxadustat (FG-4592) is a specific hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor. We investigated the effects of FG-4592 pretreatment on survival and second choke vessels of multi-territory perforator flaps in rats. In total, 72 rats were divided into two groups (n = 36 each): the experimental (FG-4592) group and the control group. FG-4592 was administered orally as a single dose of 60 mg/kg every other day; the first drug solution was administered to the animals 7 days before the surgical procedure. On postoperative day 7, the surviving flap area was calculated. At 12 h post-surgery, in the second choke zone in the flaps, macrovascular hinges were compared by angiography and imaging, and microvascular changes were assessed by histology. Laser Doppler imaging was used to evaluate flap perfusion at the second choke zone at 12 h and 7 days after surgery. At 7 days after surgery, the flap survival area and perfusion were significantly greater in rats given FG-4592 compared with controls. At 12 h after surgery, the diameter of macrovascular and microvascular vessels, nitric oxide content, perfusion, and the protein levels of HIF-1α and inducible nitric oxide synthase were also significantly greater in FG-4592-treated rats than controls. In conclusion, pretreatment with roxadustat may improve initial flap survival and dilate the second choke zone vessels in a multi-territory perforator flap.

Disproportionality Analysis on Hypothyroidism With Roxadustat Using the Japanese Adverse Drug Event Database.

Hypoxia-inducible factor prolyl-hydroxylase inhibitor (HIF-PHI) is a novel agent for the treatment of renal anemia. HIF-PHI increases endogenous erythropoietin production by inhibiting the degradation of an erythropoietin transcription factor. Although beneficial effects are expected from HIF-PHI, its novel mechanism raises concerns regarding the risk of potential adverse events. The cases of hypothyroidism, which had not been reported in clinical trials, were reported after the administration of roxadustat in a real-world setting. However, the effects of HIF-PHIs on thyroid function have not yet been fully evaluated. This study aimed to assess the clinical impact of HIF-PHIs on thyroid function using the Japanese Adverse Drug Event Report database, a spontaneous reporting system in Japan, because HIF-PHIs were made available in Japan before they were available in other countries. Although a disproportionality signal for hypothyroidism was detected with roxadustat (reporting odds ratio [ROR]:22.1, 95% confidence interval [CI]:18.3-26.7, no signals were detected with another HIF-PHI, daprodustat (ROR:1.3, 95%CI:0.3-5.4), and epoetin beta pegol (ROR:1.2, 95%CI:0.5-2.7). Signals of hypothyroidism due to roxadustat were also detected regardless of age or sex. Approximately 50% of hypothyroidism cases were reported within 50 days of starting roxadustat use. These results indicate that roxadustat use may be related to the development of hypothyroidism. The need for monitoring of thyroid function should be alerted during roxadustat administration regardless of age or sex.

Association of Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors with Cardiovascular Events and Death in Dialysis Patients: A Systematic Review and Meta-Analysis

Background: Anemia is a common finding among patients with advanced chronic kidney disease, especially those on dialysis. The recent introduction of hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) has raised some concerns about the cardiovascular and thrombotic complications of this class of drugs. Objectives: This meta-analysis aimed to assess the safety of HIF-PHIs in patients with end-stage kidney disease (ESKD) versus standard therapy with erythropoiesis-stimulating agents (ESAs). Methods: Databases were searched on April 2022. Studies that reported incidence of all-cause mortality; major cardiovascular adverse events (MACEs); myocardial infarction (MI); stroke and thrombotic events in the use of HIF-PHIs or ESA on ESKD patients in hemodialysis or peritoneal dialysis were evaluated. Data were extracted from published reports, and quality assessment was performed per Cochrane recommendations. Results: 12,821 patients from ten randomized controlled trials were included in this study. Most patients (83%) were on hemodialysis. 6,461 (50.3%) were using HIF-PHIs, and 6,360 (49.6%) were in the ESA group. The pooled estimated incidence of all-cause mortality was 769 in the HIF-PHIs group (relative-risk ratios (RR): 1.04; confidence interval (CI): 0.95–1.14; p = 0.52; I² = 0%). There was no difference in the groups regarding the outcomes of MACE in the analysis of the three studies that reported this outcome (RR: 0.95; CI: 0.87–1.04; p = 0.69; I² = 0%). In addition, there was no statistical difference among the outcomes of MI, stroke, or thrombotic events. Conclusions: Among patients with ESKD on dialysis, the use of HIF-PHIs was non-inferior regarding the safety outcomes when compared to standard of care therapy.

Structural basis for binding of the renal carcinoma target hypoxia-inducible factor 2α to prolyl hydroxylase domain 2.

The hypoxia-inducible factor (HIF) prolyl-hydroxylases (human PHD1-3) catalyze prolyl hydroxylation in oxygen-dependent degradation (ODD) domains of HIFα isoforms, modifications that signal for HIFα proteasomal degradation in an oxygen-dependent manner. PHD inhibitors are used for treatment of anemia in kidney disease. Increased erythropoietin (EPO) in patients with familial/idiopathic erythrocytosis and pulmonary hypertension is associated with mutations in EGLN1 (PHD2) and EPAS1 (HIF2α); a drug inhibiting HIF2α activity is used for clear cell renal cell carcinoma (ccRCC) treatment. We report crystal structures of PHD2 complexed with the C-terminal HIF2α-ODD in the presence of its 2-oxoglutarate cosubstrate or N-oxalylglycine inhibitor. Combined with the reported PHD2.HIFα-ODD structures and biochemical studies, the results inform on the different PHD.HIFα-ODD binding modes and the potential effects of clinically observed mutations in HIFα and PHD2 genes. They may help enable new therapeutic avenues, including PHD isoform-selective inhibitors and sequestration of HIF2α by the PHDs for ccRCC treatment.