Anemia of chronic disease (ACD) is the most frequent clinical issue in patients with chronic disease. ACD is usually secondary to chronic kidney disease (CKD), cancer, and chronic infection, which is associated with poor health outcomes, increased morbidity and mortality, and substantial economic costs. Current treatment options for ACD are very limited. The discovery of the hypoxia-inducible factor-prolyl hydroxylase (HIF-PHD) pathway made it possible to develop novel therapeutic agents (such as hypoxia-inducible factor-prolyl hydroxylase inhibitor, HIF-PHI) to treat ACD by stabilizing HIF and subsequently promoting endogenous erythropoietin (EPO) production and iron absorption and utilization. Thus, HIF-PHIs appear to open a new door for the treatment of ACD patients with a novel mechanism. Here, we comprehensively reviewed the latest advancements in the application of HIF-PHIs in ACD. Specifically, we highlighted the key features of HIF-PHIs on ACD, such as stimulation of endogenous EPO, handling iron metabolism, inflammation-independent, and prolonging lifespan of red blood cells. In conclusion, the success of HIF-PHIs in the treatment of ACD may expand the therapeutic opportunity for other types of anemia beyond renal anemia.
Humans ; Anemia/metabolism* ; Chronic Disease ; Hypoxia-Inducible Factor-Proline Dioxygenases/metabolism* ; Erythropoietin/metabolism* ; Prolyl-Hydroxylase Inhibitors/therapeutic use* ; Animals ; Renal Insufficiency, Chronic

BACKGROUND: Temozolomide (TMZ) resistance is a significant challenge in treating glioblastoma (GBM). Collagen remodeling has been shown to be a critical factor for therapy resistance in other cancers. This study aimed to investigate the mechanism of TMZ chemoresistance by GBM cells reprogramming collagens. METHODS: Key extracellular matrix components, including collagens, were examined in paired primary and recurrent GBM samples as well as in TMZ-treated spontaneous and grafted GBM murine models. Human GBM cell lines (U251, TS667) and mouse primary GBM cells were used for in vitro studies. RNA-sequencing analysis, chromatin immunoprecipitation, immunoprecipitation-mass spectrometry, and co-immunoprecipitation assays were conducted to explore the mechanisms involved in collagen accumulation. A series of in vitro and in vivo experiments were designed to assess the role of the collagen regulators prolyl 4-hydroxylase subunit alpha 1 (P4HA1) and yes-associated protein (YAP) in sensitizing GBM cells to TMZ. RESULTS: This study revealed that TMZ exposure significantly elevated collagen type I (COL I) expression in both GBM patients and murine models. Collagen accumulation sustained GBM cell survival under TMZ-induced stress, contributing to enhanced TMZ resistance. Mechanistically, P4HA1 directly binded to and hydroxylated YAP, preventing ubiquitination-mediated YAP degradation. Stabilized YAP robustly drove collagen type I alpha 1 ( COL1A1) transcription, leading to increased collagen deposition. Disruption of the P4HA1-YAP axis effectively reduced COL I deposition, sensitized GBM cells to TMZ, and significantly improved mouse survival. CONCLUSION P4HA1 maintained YAP-mediated COL1A1 transcription, leading to collagen accumulation and promoting chemoresistance in GBM.
Temozolomide ; Humans ; Glioblastoma/drug therapy* ; Animals ; Mice ; Cell Line, Tumor ; Drug Resistance, Neoplasm/genetics* ; YAP-Signaling Proteins ; Hydroxylation ; Dacarbazine/pharmacology* ; Adaptor Proteins, Signal Transducing/metabolism* ; Transcription Factors/metabolism* ; Collagen/biosynthesis* ; Collagen Type I/metabolism* ; Prolyl Hydroxylases/metabolism* ; Antineoplastic Agents, Alkylating/therapeutic use*

Chromodomain-helicase-DNA-binding protein 1 (CHD1) deletion is among the most common mutations in prostate cancer (PCa), but its role remains unclear. In this study, RNA sequencing was conducted in PCa cells after clustered regularly interspaced palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9)-based CHD1 knockout. Gene set enrichment analysis (GSEA) indicated upregulation of hypoxia-related pathways. A subsequent study confirmed that CHD1 deletion significantly upregulated hypoxia-inducible factor 1α (HIF1α) expression. Mechanistic investigation revealed that CHD1 deletion upregulated HIF1α by transcriptionally downregulating prolyl hydroxylase domain protein 2 (PHD2), a prolyl hydroxylase catalyzing the hydroxylation of HIF1α and thus promoting its degradation by the E3 ligase von Hippel-Lindau tumor suppressor (VHL). Functional analysis showed that CHD1 deletion promoted angiogenesis and glycolysis, possibly through HIF1α target genes. Taken together, these findings indicate that CHD1 deletion enhances HIF1α expression through PHD2 downregulation and therefore promotes angiogenesis and metabolic reprogramming in PCa.
Male ; Humans ; Von Hippel-Lindau Tumor Suppressor Protein/metabolism* ; DNA-Binding Proteins/metabolism* ; Prolyl Hydroxylases/metabolism* ; Hypoxia ; Prostatic Neoplasms/pathology* ; Glycolysis ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Cell Line, Tumor ; DNA Helicases/metabolism*

OBJECTIVE: To investigate the mechanism of shikonin-induced death of human hepatocellular carcinoma SMMC-7721 cells. METHODS: Cultured SMMC-7721 cells and normal hepatocytes (L-02 cells) were treated with 4, 8, or 16 μmol/L shikonin, and the changes in cell viability was assessed using MTT assay. The levels of ATP and lactic acid in the cell cultures were detected using commercial kits. Co-immunoprecipitation and immunofluorescence staining were used to determine the relationship among pyruvate kinase M2 (PKM2), prolyl hydroxylase 3 (PHD3), and hypoxia-inducible factor-1α (HIF-1α). The expressions of PHD3, PKM2, HIF-1α, Bax, cleaved caspase-3, and Bcl-2 in SMMC-7721 cells were detected with Western blotting, and cell apoptosis was analyzed with annexin V-FITC/PI staining. The effects of RNA interference of PKM2 on PHD3 and HIF-1α expressions in SMMC-7721 cells were detected using Western blotting. RESULTS: The IC₅₀ of shikonin against SMMC-7721 and L-02 cells was 8.041 μmol/L and 31.75 μmol/L, respectively. Treatment with shikonin significantly inhibited the protein expressions of PKM2, HIF-1α and PHD3 and nuclear translocation of PKM2 and HIF-1α in SMMC-7721 cells. Coimmunoprecipitation and immunofluorescence staining confirmed that shikonin inhibited the formation of PKM2/PHD3/HIF-1α complex and significantly reduced the contents of lactic acid and ATP in SMMC-7721 cells (P < 0.05). The expressions of PHD3 and HIF-1α decreased significantly after PKM2 knockdown (P < 0.05). Shikonin treatment significantly increased the apoptosis rate, enhanced the expressions of Bax and cleaved caspase-3, and decreased Bcl-2 expression in SMMC-7721 cells (P < 0.05). CONCLUSIONS Shikonin induces apoptosis of SMMC-7721 cells possibly by inhibiting aerobic glycolysis through the PKM2/PHD3/HIF-1α signaling pathway to cause energy supply dysfunction in the cells.
Humans ; Prolyl Hydroxylases ; Carcinoma, Hepatocellular ; Caspase 3 ; bcl-2-Associated X Protein ; Liver Neoplasms ; Signal Transduction ; Apoptosis ; Adenosine Triphosphate

OBJECTIVE: To investigate the role of proline 4-hydroxylase Ⅱ (P4HA2) in the occurrence and progression of liver cancer. METHODS: GEPIA and Human Protein Atlas database were used to predict the expression of P4HA2 in hepatocellular carcinoma (HCC), and K-M plotter online database was used to analyze the relationship between P4HA2 expression and the prognosis of HCC. We also examined the expressions of P4HA2 in HCC cells and normal hepatocytes using qRT-PCR and Western blotting. With lentivirus-mediated RNA interference, P4HA2 expression was knocked down in hepatoma SNU-449 and Hep-3B cells, and the changes in cell proliferation, migration and invasion were assessed using cell counting kit-8 (CCK-8) assay, colony formation test, scratch test and Transwell assay. The changes in the expressions of epithelial-mesenchymal transition (EMT) and PI3K/Akt/mTOR signal pathway-related proteins were detected using Western blotting. RESULTS: Online database analysis showed that the expression of P4HA2 was significantly higher in HCC tissues than in normal liver tissues (P < 0.05). The expression levels of P4HA2 mRNA and protein were also significantly higher in HCC cell lines than in normal hepatocytes (P < 0.01). Lentivirus-mediated RNA interference of P4HA2 significantly lowered the expression levels of P4HA2 mRNA and protein in the hepatoma cells (P < 0.05) and caused obvious inhibition of cell proliferation, migration and invasion. P4HA2 knockdown significantly increased the expression of E-cadherin protein, lowered the expressions of N-cadherin and Snail, and obviously decreased the expressions of phosphorylated PI3K, AKT and mTOR (P < 0.05). CONCLUSION P4HA2 enhances the proliferation, migration, invasion, and EMT of hepatoma cells by activating the PI3K/Akt/mTOR signaling pathway to promote the occurrence and progression of liver cancer.
Carcinoma, Hepatocellular/pathology* ; Cell Line, Tumor ; Cell Movement/genetics* ; Cell Proliferation/genetics* ; Humans ; Liver Neoplasms/pathology* ; Phosphatidylinositol 3-Kinases/metabolism* ; Prolyl Hydroxylases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; RNA, Messenger ; Signal Transduction ; TOR Serine-Threonine Kinases/metabolism*

OBJECTIVE: To observe the effect of Biantie (bian stone plaste) pretreatment on serum level of prolyl hydroxylase domain 2 (PHD2) and hypoxia-inducible factor-1α (HIF-1α) in rats with acute hypobaric hypoxia induced-brain injury, and to explore the possible mechanism of Biantie on preventing brain injury at high altitude. METHODS: Forty-five male SD rats were randomly divided into a blank group, a model group, a Biantie group, a medication group and a Biantie+inhibitor group, 9 rats in each group. The rats in the Biantie group the and the Biantie+inhibitor group were pretreated with Biantie at "Taiyuan" (LU 9), "Neiguan" (PC 6) and "Renying" (ST 9), 2 h each time, once a day; the rats in the medication group were treated with intragastric administration of rhodiola capsule solution (280 mg/kg) for 14 d; the rats in the Biantie+inhibitor group were intraperitoneally injected with the PHD inhibitor dimethyloxalyl glycine (DMOG) at a dose of 40 mg/kg 24 h before the establishment of the model. After the intervention, except for the blank group, the rats in the remaining 4 groups were placed in the oxygen chamber to simulate a high-altitude environment to establish the acute hypobaric hypoxia brain injury model. The arterial blood-gas analysis indexes [blood oxygen saturation (SaO₂), lactic acid (Lac), blood sodium (Na⁺), blood potassium (K⁺)] and brain water content were detected in each group; the histomorphology of cerebral cortex was observed by HE staining; the serum levels of PHD2 and HIF-1α as well as vascular endothelial growth factor (VEGF) were detected by ELISA; the VEGF protein expression in brain tissue was detected by Western blot; the VEGF mRNA expression in brain tissue was detected by real-time fluorescent quantitative PCR. RESULTS: Compared with the blank group, the levels of SaO₂ and Na⁺ in the model group were decreased (P<0.05), while the levels of Lac and K⁺ as well as the water content of brain tissue were increased (P<0.05). Compared with the model group, the level of SaO₂ in the Biantie group and the medication group was increased (P<0.05), while the levels of Lac, K⁺ and the water content of brain tissue were decreased (P<0.05); the level of Na⁺ in the Biantie group was increased (P<0.05). Compared with the Biantie group, the level of SaO₂ in the Biantie+inhibitor group was decreased (P<0.05), and the level of Lac and the water content of brain tissue were increased (P<0.05). In the model group, the cortical tissue cells were loose and disordered, the cortical blood vessels were dilated, and the cells were obviously swollen; the anoxic injury in the Biantie group and the medication group was lighter, and the anoxic injury in the Biantie+inhibitor group was more obvious than that in the Biantie group. Compared with the blank group, the serum PHD2 content in the model group was decreased and the HIF-1α content was increased (P<0.05), and the content of VEGF in serum and VEGF protein and mRNA expressions in brain were increased (P<0.05). Compared with the model group, the content of PHD2 in serum in the Biantie group and the medication group was increased (P<0.05), and the level of HIF-1α was decreased (P<0.05), and the content of VEGF in serum as well as VEGF protein and mRNA expressions in brain were decreased (P<0.05). Compared with the Biantie group, the serum PHD2 content in the Biantie+inhibitor group was decreased and HIF-1α level were increased (P<0.05), and the content of VEGF in serum as well as VEGF mRNA expression in brain were increased (P<0.05). CONCLUSION Biantie at "Taiyuan" (LU 9), "Neiguan" (PC 6) and "Renying" (ST 9) could regulate serum PHD2/HIF-1α to down-regulate VEGF expression, reduce brain edema and enhance anti-hypoxia ability, so as to achieve the purpose of preventing brain injury at high altitude.
Animals ; Rats ; Male ; Prolyl Hydroxylases/metabolism* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Vascular Endothelial Growth Factor A/metabolism* ; Rats, Sprague-Dawley ; Procollagen-Proline Dioxygenase/metabolism* ; Brain Injuries ; Brain/metabolism* ; RNA, Messenger ; Water

Hypoxia-inducible factors (HIFs) are one of the primary transcription factors regulating oxygen balance, and their stability is determined by the hydroxylation state of the prolyl hydroxylase domain (PHD) that is sensitive to oxygen. In recent years, studies have shown that HIFs-prolyl hydroxylases (PHDs) oxygen-sensing pathway is involved in the process of cellular ferroptosis. Ferroptosis, a new type of cell death, different from necrosis, apoptosis, necrotizing apoptosis, and pyroptosis, is essentially a programmed death caused by the accumulation of iron-dependent lipid peroxides in cells. This paper focuses on the role and mechanism of the HIFs-PHDs oxygen-sensing pathway in cellular ferroptosis involved in nerve diseases, tumors, lung injury, and chemical nerve damage from three aspects of iron metabolism, lipid metabolism, and glutathione (GSH) synthesis/metabolism. This review will provide a theoretical basis and new ideas for the development of novel drugs targeting the HIFs-PHDs oxygen-sensing pathway and capable of regulating ferroptosis for the treatment of diseases related to ferroptosis such as nervous system diseases and tumors.
Apoptosis ; Basic Helix-Loop-Helix Transcription Factors ; Ferroptosis ; Oxygen ; Prolyl Hydroxylases

Hypoxia inducible factor (HIF)-stabilizers are being developed for the renal anemia treatment. This small molecules inhibit prolyl hydroxylase domain (PHD)-containing enzymes, causing HIF activation instead of degradation under the state of normoxia, finally increase production of intrinsic erythropoiesis. Current treatment guidelines suggest that renal anemia should be treated mainly with iron and erythropoiesis stimulating agents (ESAs). But there are several complications and concerns such as hypertension, ESA refractory anemia and increased cardiovascular mortality in using ESAs. Advantages of HIF stabilizers over ESAs are orally available, no dose-up requirement for inflammation. So far new HIF stabilizers showed efficacy and safety in renal anemia treatment. This new therapeutic agent may emerge as a standard treatment option for renal anmia treatment.
Anemia ; Anemia, Refractory ; Anoxia ; Erythropoiesis ; Hematinics ; Hepcidins ; Humans ; Hypertension ; Inflammation ; Iron ; Mortality ; Prolyl Hydroxylases ; Renal Insufficiency, Chronic

Renal anemia, mainly caused by the deficiencies of erythropoietin (EPO) and iron metabolism disorder, is one of the most common complications of chronic kidney disease. Hypoxia-inducible factor (HIF) is a class of transcription factors responsible for maintaining homeostasis during oxygen deprivation. In normoxia, HIF is degraded by prolyl hydroxylase (PHD). While under hypoxic conditions, the hydroxylation activity of PHD is inhibited, and the cellular concentration of HIF is elevated, resulting in an increase in endogenous EPO production and iron absorption. Therefore, this regulating pathway, also termed as the HIF-PHD axis, has become a promising therapeutic target of treating renal anemia. Several innovative drugs acting as selective HIF-PHD inhibitors have been successfully developed in the past years, and some of them are undergoing clinical trials. In this review, we will introduce the definition and regulatory mechanism of HIF-PHD axis, as well as current insights into its physiologic and therapeutic role in renal anemia.
Anemia ; enzymology ; pathology ; Humans ; Hypoxia ; pathology ; Hypoxia-Inducible Factor 1 ; metabolism ; Kidney Diseases ; enzymology ; pathology ; Oxygen ; Prolyl Hydroxylases ; metabolism

OBJECTIVE: Antidepressants are known to positively influence several factors in patients with depressive disorders, resulting in increased neurogenesis and subsequent relief of depressive disorders. To study the effects of venlafaxine during neural differentiation at the cellular level, we looked at its effect on protein expression and regulation mechanisms during neural differentiation. METHODS: After exposing NCCIT cell-derived EBs to venlafaxine during differentiation (1 day and 7 days), changes in protein expression were analyzed by 2-DE and MALDI-TOF MS analysis. Gene levels of proteins regulated by venlafaxine were analyzed by real-time RT-PCR. RESULTS: Treatment with venlafaxine decreased expression of prolyl 4-hydroxylase (P4HB), ubiquitin-conjugating enzyme E2K (HIP2) and plastin 3 (T-plastin), and up-regulated expression of growth factor beta-3 (TGF-beta3), dihydropyrimidinase-like 3 (DPYSL3), and pyruvate kinase (PKM) after differentiation for 1 and 7 days. In cells exposed to venlafaxine, the mRNA expression patterns of HIP2 and PKM, which function as negative and positive regulators of differentiation and neuronal survival, respectively, were consistent with the observed changes in protein expression. CONCLUSION: Our findings may contribute to improve understanding of molecular mechanism of venlafaxine.
Antidepressive Agents ; Depression ; Depressive Disorder ; Humans ; Neurogenesis ; Neurons ; Prolyl Hydroxylases ; Proteomics ; Pyruvate Kinase ; RNA, Messenger ; Venlafaxine Hydrochloride