EpoR Expression Research Articles

Erythropoietin regulates energy metabolism through EPO-EpoR-RUNX1 axis

Erythropoietin (EPO) plays a key role in energy metabolism, with EPO receptor (EpoR) expression in white adipose tissue (WAT) mediating its metabolic activity. Here, we show that male mice lacking EpoR in adipose tissue exhibit increased fat mass and susceptibility to diet-induced obesity. Our findings indicate that EpoR is present in WAT, brown adipose tissue, and skeletal muscle. Elevated EPO in male mice improves glucose tolerance and insulin sensitivity while reducing expression of lipogenic-associated genes in WAT, which is linked to an increase in transcription factor RUNX1 that directly inhibits lipogenic genes expression. EPO treatment in wild-type male mice decreases fat mass and lipogenic gene expression and increase in RUNX1 protein in adipose tissue which is not observed in adipose tissue EpoR ablation mice. EPO treatment decreases WAT ubiquitin ligase FBXW7 expression and increases RUNX1 stability, providing evidence that EPO regulates energy metabolism in male mice through the EPO-EpoR-RUNX1 axis.

Angelica sinensis polysaccharides ameliorate 5-FU-induced stress anemia via promoting extramedullary erythroblastic island central macrophage-mediated erythroid differentiation

BackgroundChronic anemia, especially chemotherapy-induced anemia, is a common and intractable symptom. Puzzlingly, the conventional anemic treatment may lead to various side effects, and the mechanism of stress anemia remains unclear. MethodsHere, peripheral blood, histopathological and transmission electron microscopical examination, colony forming test, flow cytometry, and qRT-PCR assay were used to investigate the effects of Angelia sinensis polysaccharide (ASP), one main active ingredient of Chinese herb medicine Angelica sinensis, on ameliorating 5-fluorouracil (5-FU)-induced stress anemia. ResultsWe found that intraperitoneal injection to a C57BL/6J mouse ASP 100 mg/kg per day for consecutive 10 days or 14 days, remarkably accelerated the recovery of RBC, hemoglobin, and hematocrit in blood. ASP alleviated 5-FU-caused impairment of bone marrow cell and BFU-E enumeration. Meanwhile, ASP antagonized 5-FU promoting extramedullary erythropoiesis in the spleen, inducing splenomegaly due to stress erythroblastic islands, and occurrence of megakaryocytes and hematopoietic precursors in splenic colonies. ASP increased splenic stress BFU-E enumeration, driving BFU-E differentiation towards Pro-E and end-stage erythroblasts. Furthermore, ASP increased the number of F4/80+VCAM-1+ splenic erythroblastic island central macrophages, upregulating genetic expression of EPOR, Emp, VCAM-1, Hmox-1, Trf, TfR1, Fpn1, Spi-C, DNase2a, Tim4, MertK, and Klf1 in splenocytes. ConclusionsOur findings indicate that the possible mechanism of chemotherapy-induced anemia is related to stress erythroid maturation arrest. Whereas, ASP may promote stress erythroid differentiation via elevated EPO sensitivity in extramedullary hematopoietic organs and enhanced macrophage-mediated adhesion, iron homeostasis and transfer, and nuclear engulfment, which may represent a promising therapeutic strategy.

Danggui-Shaoyao San alleviates cognitive impairment via enhancing HIF-1α/EPO axis in vascular dementia rats

Ethnopharmacological relevanceInvigorating blood circulation to remove blood stasis is a primary strategy in TCM for treating vascular dementia (VaD). Danggui-Shaoyao San (DSS), as a traditional prescription for neuroprotective activity, has been proved to be effective in VaD treatment. However, its precise molecular mechanisms remain incompletely understood. Aim of the studyThe specific mechanism underlying the therapeutic effects of DSS on VaD was explored by employing network pharmacology as well as in vivo and in viro experiment validation. Materials and methodsWe downloaded components of DSS from the BATMAN-TCM database for target prediction. The intersection between the components of DSS and targets, PPI network, as well as GO and KEGG enrichment analysis were then performed. Subsequently, the potential mechanism of DSS predicted by network pharmacology was assessed and validated through VaD rat model induced by 2VO operation and CoCl2-treated PC12 cells. Briefly, the DSS extract were first quantified by HPLC. Secondly, the effect of DSS on VaD was studied using MWM test, HE staining and TUNEL assay. Finally, the molecular mechanism of DSS against VaD was validated by Western blot and RT-QPCR experiments. ResultsThrough network analysis, 137 active ingredients were obtained from DSS, and 67 potential targets associated with DSS and VaD were identified. GO and KEGG analysis indicated that the action of DSS on VaD primarily involves hypoxic terms and HIF-1 pathway. In vivo validation, cognitive impairment and neuron mortality were markedly ameliorated by DSS. Additionally, DSS significantly reduced the expression of proteins related to synaptic plasticity and neuron apoptosis including PSD-95, SYP, Caspase-3 and BCL-2. Mechanistically, we confirmed DSS positively modulated the expression of HIF-1α and its downstream proteins including EPO, p-EPOR, STAT5, EPOR, and AKT1 in the hippocampus of VaD rats as well as CoCl2-induced PC12 cells. HIF-1 inhibitor YC-1 significantly diminished the protection of DSS on CoCl2-induced PC12 cell damage, with decreased HIF-1α, EPO, EPOR expression. ConclusionOur results initially demonstrated DSS could exert neuroprotective effects in VaD. The pharmacological mechanism of DSS may be related to its positive regulation on HIF-1α/EPO pathway.

Study on the TGF-β Ligand Trap Enhances Erythroid Differentiation in HEL Cell By Inhibiting Smad3 Phosphorylation

Objective: Anemia is the most common clinical manifestation of MF, and its pathogenesis may be closely related to the over activation of TGF-β signaling pathway. This study aims to establish an erythroid differentiation model by inducing HEL cells with hemin and investigate the mechanism of the TGF-β ligand trap luspatercept enhances erythroid differentiation in HEL cell. Methods: 1.ELISA was used to detect the levels of GDF11 in peripheral blood plasma in patients with MF and healthy people. 2.The erythroid differentiation model was established by inducing HEL cells with hemin. The differentiation and proliferation levels of cells were detected by benzidine staining and CCK8. The expression levels of mRNA and protein in the cells were detected by RNA-seq and TMT proteomic analysis, and verified by flow cytometry, RT-PCR and WB. 3.HEL cells were induced with 40 μM hemin as a model of erythroid differentiation. 100ng/mL GDF11 interfered with the over activation of TGF-β signal pathway in differentiated HEL cells. 5μg/mL luspatercept blocked the activation of TGF-β signaling pathway by GDF11. Divided them into three groups, named: hemin group , GDF11 group, and luspatercept group. WB was used to detect the protein levels of pSmad3 and Smad4 in nuclear. Benzidine staining and flow cytometry were used to detect the levels of cell differentiation. RT-PCR and WB were used to detect the expression levels of GATA-1 and KLF1. The changes of RNA expression were detected by RNA-seq and verified by WB. 4.All experimental data were analyzed by SPSS 22.0 statistical software. Results: 1.The GDF11 levels of plasma of MF patients were higher than those of normal people ( P=0.0411). 2.The erythroid differentiation model of HEL cells induced with 40 μM hemin was successfully constructed. The results of RNA-seq and TMT proteome analysis showed that compared with the control group, the expression of hematopoietic related genes such as GATA-1, KLF1 and EPOR in hemin group were up-regulated, and the intracellular proteins related to erythroid differentiation such as HBγ- 2, HB-α and CD235a were up-regulated. Flow cytometry indicated that the expression of CD235a in hemin group was significantly higher than that of the control group (33.83% vs81%, P<0.01). RT-PCR and WB experiment showed that the expression of GATA-1 and KLF1 in hemin group were higher than those in control group. 3.WB showed that compared with hemin group, the hyperphosphorylation of smad3 and Smad4 in nuclear levels were increased in GDF11 group. And luspatercept could inhibit the hyperphosphorylation of Smad3 and reduce Smad4 in nuclear levels of GDF11 group. Luspatercept could inhibit GDF11 mediated activation of TGF-β signaling pathway in HEL cells. 4.Compared with hemin group, the benzidine positivity rate of cells and the expression of CD235a on the cell surface in GDF11 group were significantly decreased (benzidine: 13.0% vs 9%, P<0.01; CD235a: 16.8% vs 33.83%, P<0.01), and the expression of GATA-1 and KLF1 were also decreased. GDF11 could inhibit the erythroid differentiation of HEL cells. 5.Compared with GDF11 group, the benzidine positivity rate of cells and the expression of CD235a on the cell surface in luspatercept group were significantly increased (benzidine: 29.0% vs0%, P<0.01; CD235a: 31.1% vs 16.8%, P<0.01), and the expression of GATA-1 and KLF1 were increased. Luspatercept could reverse the inhibition of GDF11 on the erythroid differentiation of HEL cells. 6.Compared with the hemin group, the expression of GATA-1, KLF1, EPOR and other genes related to hematopoiesis in GDF11 group were down-regulated, and the differentially expressed genes were related to the biological functions of ribosomal metabolism process, chromosome regulation, erythropoiesis, oxygen binding, oxidoreductase activity and so on, mainly involving erythroid differentiation, oxidative phosphorylation, iron metabolism, TGF- β, JAK-STAT and other channels. Luspatercept could restore the expression of GATA-1, KLF1, EPOR and other genes by inhibiting the pathway over-activated by GDF11. Conclusion: Hemin could induce the erythroid differentiation of HEL cells. The TGF-β ligand trap luspatercept could inhibit GDF11-mediated hyperphosphorylation of Smad3 in HEL cells and promote the erythroid differentiation of HEL cells. Luspatercept could be a therapeutic tool for patients with myelofibrosis associated anemia.

Dual α-Globin and Truncated EPO Receptor Knockin Restores Hemoglobin Production in α-Thalassemia-Derived Hematopoietic Stem and Progenitor Cells

Introduction: α-thalassemia major (ATM) is an autosomal recessive disorder where all four copies of the α-globin gene are deleted. A traditionally lethal disease due to severe fetal hypoxia, this condition is now survivable due to the advent of in utero blood transfusions. However, patients still require life-long transfusions postnatally. While allogeneic hematopoietic stem cell transplant (HSCT) can provide a definitive cure, it is limited by the paucity of suitable donors, has a high morbidity and mortality due the prerequisite myeloablative regimens, and carries the risk of immune rejection and graft-versus-host disease. Here, we describe a CRISPR/AAV-mediated genome editing strategy to restore a full-length copy of the α-globin gene at the β-globin locus in ATM patient-derived HSCs to restore normal hemoglobin production to a patient's red blood cells (RBCs). Methods: We identified a Cas9 gRNA that efficiently introduced indels at the HBB locus as well as an AAV6 vector that mediated efficient integration into the start codon of HBB. After designing and testing integration cassettes, we developed two candidate vectors that insert a HBA1 transgene at the HBB locus, with one bicistronic vector that also expresses a truncated form of the erythropoietin receptor (t EPOR) to increase erythropoietic output from edited HSCs. We used this approach to edit CD34 + HSCs derived from the bone marrow of three patients with ATM. Edited cells were cultured for 16 days in RBC differentiation media. Editing rates were quantified by a custom ddPCR assay. To determine the transcriptional response to these editing strategies, bulk RNA sequencing was performed comparing wild-type cells and patient cells that underwent respective editing conditions. Lastly, α-globin protein production was quantified using tetramer and single-globin high protein liquid chromatography (HPLC). Results: While effective editing frequencies in ATM HSCs were achieved by the HBA integration vector (39% edited alleles), we observed that editing rates increased over the course of RBC differentiation in the combined HBA+t EPOR edited condition, reaching 76% edited alleles by day 16. We also found that total cell counts by the end of RBC differentiation more than doubled (2.2-fold) in the HBA+t EPOR condition compared to the HBA alone condition. RNA sequencing of edited ATM-derived HSCs following RBC differentiation revealed an upregulation of HBA1, HBA2, and EPOR transcripts compared to unedited patient cells. These results were supported by HPLC, which demonstrated restoration of hemoglobin tetramers, including fetal hemoglobin (α+γ subunits), adult hemoglobin (α+β subunits), and hemoglobin A2 (α+δ subunits) compared to unedited patient cells. Complementing this with globin single chain analysis found that we had achieved 11% restoration of α-globin compared to wild-type levels. In spite of integration at the HBB locus, neither RNA sequencing nor HPLC showed disruption of β-globin production. α-globin production with a concomitant decrease in the formation of toxic β-globin dimers was confirmed by Western blot, with restoration of the normal balance of α-globin to dimeric β-globin in edited cells to wild-type levels. Conclusions: To our knowledge, these results demonstrate for the first time that gene therapy or genome editing may be used to increase α-globin production in ATM patient-derived RBCs. We found that the editing strategy that paired site-specific α-globin integration with t EPOR expression achieved the highest editing frequencies, greatest production of edited cells, and the most robust production of α-globin protein compared to α-globin integration alone. By increasing erythropoietic output using t EPOR, this approach has the potential to overcome some of the clinical challenges previously seen in HSCT for the hemoglobinopathies, including low editing and engraftment rates. Moreover, as patients with severe anemia such those with ATM have increased levels of circulating erythropoietin due to severe anemia, a t EPOR-based enrichment strategy is likely to be especially potent following transplantation into ATM bone marrow. We believe this could allow clinicians to reduce or eliminate the need for myeloablation, which stand as a major barrier to HSCT safety and efficacy. These findings support development of a definitive ex vivo autologous genome editing strategy that may be curative for ATM.

Classification and genetics of pediatric B-other acute lymphoblastic leukemia by targeted RNA sequencing.

Acute lymphoblastic leukemia (ALL) can be classified into different subgroups based on recurrent genetic alterations. Here, targeted RNA sequencing was used to identify the novel subgroups of ALL in 144 B-other and 40 "classical" ALL samples. The classical TCF3-PBX1, ETV6-RUNX1, KMT2A-rearranged, and BCR-ABL1, and novel P2RY8-CRLF2, ABL-, JAK2-, ZNF384-, MEF2D-, and NUTM1-fusions were easily identified by fusion transcript analysis. IGH-CRLF2 and IGH-EPOR were found by abnormally high levels of expression of CRLF2 or EPOR. DUX4-rearranged was identified by the unusual expression of DUX4 genes and an alternative exon of ERG, or by clustering analysis of gene expression. PAX5-driven ALL, including fusions, intragenic amplifications, and mutations were identified by single-nucleotide variant analysis and manual inspection using the IGV software. Exon junction analysis allowed detection of some intragenic ERG and IKZF1 deletions. CRLF2-high associated with initial white blood cell (WBC) counts of ≥50× 103/μL and GATA3 risk alleles (rs3781093 and rs3824662), whereas ABL/JAK2/EPOR-fusions associated with high WBC counts, National Cancer Institute's high-risk classification, and IKZF1del. ZNF384-fusions associated with CALLA-negativity and NUTM1-fusions in infants. In conclusion, targeted RNA sequencing further classified 66.7% (96 of 144) B-other ALL cases. All BCP-ALL subgroups, except for iAMP21, hyperdiploid and hypodiploid cases, were identified. Curiously, we observed higher frequencies of females within B-rest ALLs and males in PAX5-driven cases.

Iron Chelation Improves Ineffective Erythropoiesis and Iron Overload in a Mouse Model of Myelodysplastic Syndrome

Myelodysplastic syndrome (MDS) is a heterogeneous group of bone marrow stem cell disorders characterized by ineffective hematopoiesis and cytopenias, most commonly anemia. Patients are treated with periodic red cell (RBC) transfusions, resulting in iron overload. Iron overload in MDS patients correlates with decreased survival, yet despite the availability of effective, safe, and orally administered iron chelation therapy, the treatment of iron overload in MDS remains controversial. The TELESTO trial, using deferasirox in low risk MDS patients, revealed an increase in event-free survival without impacting overall survival, hemoglobin, or RBC transfusion requirements [Angelucci Ann Int Med 2020]. However, iron chelators have different affinities for iron relative to transferrin; deferiprone has the lowest affinity of available iron chelators [Sohn Blood 2008], consistent with its ability to increase hepcidin expression in mice [Schmidt Am J Hematol 2015; Casu haematol 2016]. We hypothesize that deferiprone (DFP) impacts systemic and cellular iron distribution to enhance erythropoiesis in MDS. To test this hypothesis, we employed a highly penetrant well-established mouse model of MDS, NUP98:HOXD13 fusion transgenic mice. These MDS mice exhibit hypercellular marrow, increased apoptosis in the bone marrow compartment, and impaired survival relative to control; a proportion of mice progress to acute leukemic transformation after 7 months of age [Lin Blood 2005]. Using MDS mice, we further characterize parameters of iron trafficking in erythroblasts, evaluate the effects of DFP on erythropoiesis and iron distribution, and provide correlatory evidence in stem and progenitor cells from MDS patients. MDS mice were treated at 5 months of age with 1.25 mg/mL DFP in the drinking water for 4 weeks and compared with untreated MDS mice. Our results characterize an iron overload phenotype with aberrant erythropoiesis in MDS mice, reversed in DFP-treated MDS mice (Figure 1). Specifically, DFP leads to a redistribution of iron from liver and spleen to increase serum iron concentration and transferrin saturation, increased hemoglobin and RBC concentration in circulation, and normalized hepcidin responsiveness to iron. While MDS mice exhibit relatively decreased WBC count, no changes in WBC count are observed in DFP-treated MDS mice. Importantly, serum erythropoietin (Epo) concentration, splenomegaly, expanded erythropoiesis and erythroblast differentiation in the bone marrow are normalized in DFP-treated MDS mice. As expected when erythropoiesis is reversed, erythroblast expression of Fam132b (erythroferrone) is suppressed but no changes in STAT5 or AKT signaling, pathways downstream of Epo, are evident in DFP-treated MDS mice. These findings suggest that the expected changes in signaling downstream of Epo are unaffected by DFP administration, implicating possible changes in erythroblast Epor expression in DFP-treated MDS mice. We used sorted bone marrow to evaluate Epor expression in progressive stages of terminal erythropoiesis and demonstrate decreased Epor expression in later stage bone marrow erythroblasts from MDS mice, normalized in DFP-treated MDS mice. These findings provide evidence that increased Epor expression is a potential mechanism by which DFP leads to enhanced Epo-responsiveness and enhanced erythroblast differentiation despite decreased serum Epo concentration in MDS mice. In addition, we demonstrate for the first time increased ferritin concentration and normalized Tfr1, Pcbp1 and Ncoa4 expression in late stage erythroblasts from DFP-treated MDS mice, evidence of aberrant iron trafficking in MDS erythroblasts and their normalization with DFP treatment (Figure 2). Importantly, this effect is not observed in DFP-treated WT mice. Our data also provides evidence that reversal of ineffective erythropoiesis in DFP-treated MDS mice occurs independently of effects on erythroblast apoptosis. Finally, we confirm increased expression of genes involved in Epo-mediation as well as iron uptake and trafficking-Epor, Fam132b, Tfr1, Pcbp1 and Ncoa4-in stem and progenitor cells from MDS patients. Taken together, our findings provide evidence that erythroblast-specific iron metabolism is a novel potential therapeutic target to reverse ineffective erythropoiesis in MDS and provide a rationale for exploring the effect of DFP in patients with low risk MDS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Pulpal expression of erythropoietin and erythropoietin receptor after direct pulp capping in rat

This study aimed to evaluate the effect of direct pulp capping on the expression of erythropoietin (Epo) and Epo-receptor (Epor) genes in relation to the expression of inflammatory and osteogenic genes in rat pulp. Dental pulps of the first maxillary molars of Wistar Albino rats were exposed and capped with either calcium hydroxide or mineral trioxide aggregate, or were left untreated. After 4 wk, animals were euthanized, and maxillae were prepared for histological and real-time polymerase chain reaction analysis. Histological scores of pulp inflammation and mineralization, and relative expressions of Epo, Epor, inflammatory cytokines, and pulp osteogenic genes were evaluated. The capped pulps showed higher expressions of Epo, while the untreated pulps had the highest expression of Epor. Both calcium hydroxide and mineral trioxide aggregate downregulated the expression of tumor necrosis factor alpha compared to untreated controls, and upregulated transforming growth factor beta compared to healthy controls. Alkaline phosphatase expression was significantly higher in experimental groups. Relative expression of Epo negatively correlated with pulp inflammation, and positively correlated with pulp mineralization. Pulp exposure promoted expression of Epor and pro-inflammatory cytokines, while pulp capping promoted expression of Epo, alkaline phosphatase, and downregulated Epor and pro-inflammatory cytokines.

Linking erythropoietin to Treg-dependent allograft survival through myeloid cells.

Erythropoietin (EPO) has multiple nonerythropoietic functions, including immune modulation, but EPO’s effects in transplantation remain incompletely understood. We tested the mechanisms linking EPO administration to prolongation of murine heterotopic heart transplantation using WT and conditional EPO receptor–knockout (EPOR-knockout) mice as recipients. In WT controls, peritransplant administration of EPO synergized with CTLA4-Ig to prolong allograft survival (P < 0.001), reduce frequencies of donor-reactive effector CD8+ T cells in the spleen (P < 0.001) and in the graft (P < 0.05), and increase frequencies and total numbers of donor-reactive Tregs (P < 0.01 for each) versus CTLA4-Ig alone. Studies performed in conditional EPOR-knockout recipients showed that each of these differences required EPOR expression in myeloid cells but not in T cells. Analysis of mRNA isolated from spleen monocytes showed that EPO/EPOR ligation upregulated macrophage-expressed, antiinflammatory, regulatory, and pro-efferocytosis genes and downregulated selected proinflammatory genes. Taken together, the data support the conclusion that EPO promotes Treg-dependent murine cardiac allograft survival by crucially altering the phenotype and function of macrophages. Coupled with our previous documentation that EPO promotes Treg expansion in humans, the data support the need for testing the addition of EPO to costimulatory blockade-containing immunosuppression regimens in an effort to prolong human transplant survival.

Recombinant human erythropoietin accelerated the proliferation of non-small cell lung cancer cell lines and reduced the expression of VEGF, HIF-1α, and PD-L1 under a simulated hypoxic environment in vitro.

BackgroundAs erythropoietin (EPO) has been used to treat anemia in cancer patients, negative controversy has continued. Unfortunately, its effects on non‐small‐cell lung carcinoma (NSCLC) cell lines are uncertain and the phenomenon of inducing immune escape of tumor cells remains to be explored. This study aimed to provide an important basis for the application of exogenous EPO in the treatment of tumor‐associated anemia.MethodsCells were cultured in 1% O2, 5% CO2, and 94% N2 to simulate a hypoxic environment of the tumor. A549 cell line (lower expression EPOR) and NCI‐H838 cell line (higher expression EPOR) were treated with 2 and 8 U/ml recombinant human EPO (rhEPO). CCK‐8 method was used to determine the logarithmic growth phase of the cells and to detect cell proliferation. The expression levels of VEGF, HIF‐1α, and PD‐L1 were determined by western blot. One‐way ANOVA was used for statistical analysis between groups, with p < 0.05 indicating a significant difference.ResultsHypoxia itself could decrease the survival rate of NSCLC cells. Under the hypoxic condition, rhEPO induced tumor cells proliferation, especially in the NCI‐H838 cell line, where 2 U/ml rhEPO increased the total number of surviving cells (Hypoxia + rhEPO 2 U/ml vs. Hypoxia, p < 0.05). Western blot analysis showed that hypoxia upregulated the expression of VEGF, HIF‐1α, and PD‐L1 in NSCLC cell lines (Normoxia vs. Hypoxia, p < 0.05), but may not be dependent on the expression levels of EPOR. RhEPO decreased the expression levels of VEGF and HIF‐1α. In the A549 cell line, it depended on the concentration of rhEPO and was particularly obvious in HIF‐1α (Hypoxia vs. Hypoxia + rhEPO 2 U/ml vs. Hypoxia + rhEPO 8 U/ml, p < 0.05). A low concentration of rhEPO may not reduce VEGF expression. In the NCI‐H838 cell line, the effect of rhEPO on VEGF was more obvious, but it may be independent of rhEPO concentrations. The downregulation of PD‐L1 expression by rhEPO was only presented in the A549 cell line and required higher rhEPO concentrations (Hypoxia + rhEPO 8 U/ml vs. Hypoxia&Hypoxia + rhEPO 2 U/ml, p < 0.05).ConclusionThe effect of prolonged high concentrations of rhEPO under hypoxic conditions resulted in accelerated cells proliferation of non‐small‐cell lung cancer and was independent of EPOR expression levels on the cell lines surface. Hypoxia resulted in increased expression of VEGF, HIF‐1α, and PD‐L1 on the NSCLC cell lines. Under normoxic conditions, rhEPO did not affect the expression of VEGF, HIF‐1α, and PD‐L1; but under hypoxic conditions, the application of rhEPO reduced the expression of VEGF, HIF‐1α, and PD‐L1, producing an impact on the biological behavior of tumor cells.

Pan-Cancer Analysis Based on EPOR Expression With Potential Value in Prognosis and Tumor Immunity in 33 Tumors.

BackgroundErythropoietin receptor (EPOR), a member of the cytokine class I receptor family, mediates erythropoietin (EPO)-induced erythroblast proliferation and differentiation, but its significance goes beyond that. The expression and prognosis of EPOR in cancer remain unclear.MethodsThis study intended to perform a pan-cancer analysis of EPOR by bioinformatics methods. Several databases such as GTEx, TCGA, CCLE, and others were used to explore the overall situation of EPOR expression, and the correlation of EPOR expression with prognosis, microRNAs (miRNAs), immune infiltration, tumor microenvironment, immune checkpoint genes, chemokines, tumor mutation burden (TMB), microsatellite instability (MSI), methyltransferases, and DNA mismatch repair (MMR) genes in 33 tumors was analyzed. In addition, we compared the promoter methylation levels of EPOR in cancer tissues with those in normal tissues and performed protein–protein interaction network, gene–disease network, and genetic alteration analyses of EPOR, and finally enrichment analysis of EPOR-interacting proteins, co-expressed genes, and differentially expressed genes.ResultsThe TCGA database showed that EPOR expression was upregulated in BLCA, CHOL, HNSC, KIRC, LIHC, STAD, and THCA and downregulated in LUAD and LUSC. After combining the GTEx database, EPOR expression was found to be downregulated in 18 cancer tissues and upregulated in 6 cancer tissues. The CCLE database showed that EPOR expression was highest in LAML cell lines and lowest in HNSC cell lines. Survival analysis showed that high EPOR expression was positively correlated with OS in LUAD and PAAD and negatively correlated with OS in COAD, KIRC, and MESO. Moreover, EPOR had a good prognostic ability for COAD, LUAD, MESO, and PAAD and also influenced progression-free survival, disease-specific survival, disease-free survival, and progression-free interval in specific tumors. Further, EPOR was found to play a non-negligible role in tumor immunity, and a correlation of EPOR with miRNAs, TMB, MSI, and MMR genes and methyltransferases was confirmed to some extent. In addition, the enrichment analysis revealed that EPOR is involved in multiple cancer-related pathways.ConclusionThe general situation of EPOR expression in cancer provided a valuable clinical reference. EPOR may be target gene of hsa-miR-575, etc. A pan-cancer analysis of panoramic schema revealed that EPOR not only may play an important role in mediating EPO-induced erythroblast proliferation and differentiation but also has potential value in tumor immunity and is expected to be a prognostic marker for specific cancers.

EpoR-tdTomato-Cre mice enable identification of EpoR expression in subsets of tissue macrophages and hematopoietic cells

AbstractThe erythropoietin receptor (EpoR) has traditionally been thought of as an erythroid-specific gene. Notably, accumulating evidence suggests that EpoR is expressed well beyond erythroid cells. However, the expression of EpoR in non-erythroid cells has been controversial. In this study, we generated EpoR-tdTomato-Cre mice and used them to examine the expression of EpoR in tissue macrophages and hematopoietic cells. We show that in marked contrast to the previously available EpoR-eGFPcre mice, in which a very weak eGFP signal was detected in erythroid cells, tdTomato was readily detectable in both fetal liver (FL) and bone marrow (BM) erythroid cells at all developmental stages and exhibited dynamic changes during erythropoiesis. Consistent with our recent finding that erythroblastic island (EBI) macrophages are characterized by the expression of EpoR, tdTomato was readily detected in both FL and BM EBI macrophages. Moreover, tdTomato was also detected in subsets of hematopoietic stem cells, progenitors, megakaryocytes, and B cells in BM as well as in spleen red pulp macrophages and liver Kupffer cells. The expression of EpoR was further shown by the EpoR-tdTomato-Cre–mediated excision of the floxed STOP sequence. Importantly, EPO injection selectively promoted proliferation of the EpoR-expressing cells and induced erythroid lineage bias during hematopoiesis. Our findings imply broad roles for EPO/EpoR in hematopoiesis that warrant further investigation. The EpoR-tdTomato-Cre mouse line provides a powerful tool to facilitate future studies on EpoR expression and regulation in various non-hematopoietic cells and to conditionally manipulate gene expression in EpoR-expressing cells for functional studies.

218-LB: Age, Sex, and Fat Mass Affects Erythropoietin Metabolic Response in Mice

Erythropoietin (EPO) is required for erythrocyte production. However, EPO receptor (EpoR) extends beyond erythroid tissue and ΔEpoR mice with EpoR restricted to hematopoietic tissue show an increase in fat mass. At 3 months of age, ΔEpoR mice show no difference in body weight compared with wild type (WT, C57BL/6) mice. By 6 months of age, male body weights of ΔEpoR mice are greater than WT mice, and at 8+ months body weights of male and female ΔEpoR mice are greater than their WT counterparts. To assess EPO activity on glucose homeostasis and fat mass, mice were fed a high fat diet (HFD, 60% kCal fat) and treated with EPO (3000U/kg 3X per week) or saline for 3 weeks at age 3, 6, and 8+ months. EPO increased hematocrit in all mice. EPO treatment in male WT mice reduces weight and fat mass at 6 and 8+ months of age, when their fat mass is 35% or greater with saline treatment. Female WT mice treated with EPO do not show significantly less weight or fat mass at any age. EPO treatment does not affect weight or fat mass in ΔEpoR mice. With HFD feeding and EPO treatment in 3 month old mice, body weights are not different between WT and ΔEpoR mice although fat mass is significantly higher in ΔEpoR mice. At 6 months, body weight and fat mass in males are greater in ΔEpoR than WT, while ΔEpoR females show no difference in body weight but significantly more fat mass compared with WT females. In the older mice (8+ months old), both sexes of ΔEpoR mice are significantly heavier and fatter than WT mice. EPO treatment improves glucose tolerance in female ΔEpoR mice at 3 and 6 months but not at 8+months, whereas male ΔEpoR mice only showed improvement at 3 months, not at 6 and 8+months. In male and female WT mice, EPO improves glucose metabolism at 3 and 6 months, and to a lesser extent at 8+ months with greater improvement in mice with &amp;lt;35% fat mass. These data show that EPO regulates metabolism in a sex and age dependent manner mediated via EpoR expression in non-hematopoietic tissue and is influenced by level of fat mass. Disclosure H. Rogers: None. C. T. Noguchi: None.

Erythropoietin Protects against Diffuse Alveolar Hemorrhage in Mice by Regulating Macrophage Polarization through the EPOR/JAK2/STAT3 Axis.

Macrophages play an important role in the pathogenesis of systemic lupus erythematosus-associated diffuse alveolar hemorrhage (DAH). The immunomodulation of macrophage responses might be a potential approach for the prevention and treatment of DAH. Erythropoietin (EPO) could regulate macrophage bioactivities by binding to the EPO receptor expressing on macrophages. This study assessed the effects of EPO on DAH protection using an immune-mediated DAH murine model with macrophages as the major contributor. A DAH murine model was established in female C57BL/6 mice by an i.p. injection of pristane. We found that EPO administration alleviates DAH by reducing pulmonary macrophages recruitment and promoting phenotype switch toward M2 macrophages in vivo. EPO drove macrophages to the anti-inflammatory phenotype in the primary murine bone marrow-derived macrophages and macrophages cell line RAW 264.7 with LPS, IFN-γ, and IL-4 in vitro. Moreover, EPO treatment increases the expression of EPOR and decreases the expression of miR-494-3p, resulting in increased phosphorylation of JAK2 and STAT3. In conclusion, EPO can be a potential therapeutic agent in DAH by reducing cell apoptosis and regulating macrophage polarization through the EPOR/JAK2/STAT3 axis. Further studies are also needed to validate the direct target of miR-494-3p in regulating JAK2/STAT3 signaling transduction.

New insights into erythropoietin and erythropoietin receptor in laryngeal cancer tissue.

To investigate whether laryngeal cancer cells express erythropoietin (Epo) and erythropoietin receptor (EpoR) and what is their possible relationship with clinical and pathological features of the tumor.We performed immunohistochemical analysis of Epo and EpoR expression on 78 tissue samples of invasive and in situ squamous cell laryngeal carcinoma.The statistical analysis showed a weak positive and statistically significant correlation of EpoHS and EpoR HS expression levels. Epo HS and EpoR HS levels did not correlate with patient sex or age, type of diagnosis, cancer stage, histological tumor grade, presence or absence of disease recurrence, type of oncologic cancer therapy provided, or results of selected laboratory blood work. The results show a statistically significant difference in Epo expression with respect to survival.We confirmed the presence of Epo an EpoR in malignant laryngeal tumors and demonstrated the correlation between Epo expression and survival. Further studies are needed to more precisely define the role of Epo and EpoR in treatment of patients with laryngeal cancer.

Expression of the erythropoietin receptor in patients with proliferative diabetic retinopathy and its correlation with postoperative visual prognosis.

Proliferative diabetic retinopathy (PDR) is a leading cause of blindness. This study aimed to analyze the expression of the erythropoietin receptor (EpoR) in patients with PDR and its correlation with postoperative visual prognosis. Between May 2016 and May 2017, 89 patients who underwent vitreoretinal surgery (VRS) in Affiliated Hospital of North Sichuan Medical College were enrolled. Among them, 45 patients (52 eyes) with PDR and 44 patients (50 eyes) with retinal vein occlusion (RVO) made up the study group and the control group, respectively. All patients received 25G standard flattened three-channel lens-preserving VRS; all procedures were performed by the same physician. Recovery and change in best corrected visual acuity (BCVA) were observed. Subsequently, the patients were divided into group A (improved vision) and group B (no improvement in vision). The integrated optical density (IOD) value of EpoR expression among the groups were compared. Pearson's correlation analysis was used to analyze the correlation between the IOD values of EpoR and the change in visual acuity after surgery for PDR. The IOD value of EpoR in the study group was higher than that in the control group (P<0.05). The postoperative BCVA of the PDR patients was significantly higher than that before surgery (≥0.1 vs. ≤0.02, P<0.05). Of the 45 PDR patients (52 eyes), 34 patients (39 eyes) had improved visual acuity after surgery (group A), while 11 patients (13 eyes) experienced no improvement (group B). The IOD value of EpoR expression in group B was higher than that in group A (P<0.05). Pearson's correlation analysis showed that the IOD value of EpoR expression were positively correlated with the recovery. EpoR is expressed at a high level in PDR patients. The expression level of EpoR in the epiretinal membrane of PDR patients is positively correlated with the prognosis of postoperative vision. Therefore, EpoR has promise as a prognostic biomarker and a potential therapeutic target for PDR.

Erythropoietin signaling in osteoblasts is required for normal bone formation and for bone loss during erythropoietin-stimulated erythropoiesis.

Erythropoietin (EPO) regulates erythropoiesis by binding to erythropoietin receptor (Epor) on erythroid progenitor cells. Epor is also expressed on bone forming osteoblasts and bone loss accompanies EPO-stimulated erythropoiesis in mice. Mice with Epor restricted to erythroid tissue exhibit reduced bone and increased marrow adipocytes; in contrast, transgenic mice (Tg) with osteoblastic-specific deletion of Epor exhibit reduced trabecular bone with age without change in marrow adipocytes. By 12weeks, male Tg mice had 22.2% and female Tg mice had 29.6% reduced trabecular bone volume (BV) compared to controls. EPO administration (1200U/kg) for 10days reduced trabecular bone in control mice but not in Tg mice. There were no differences in numbers of osteoblasts, osteoclasts, and marrow adipocytes in Tg mice, suggesting independence of EPO signaling in mature osteoblasts, osteoclasts, and adipocytes. Female Tg mice had increased number of dying osteocytes and male Tg mice had a trend for more empty lacunae. Osteogenic cultures from Tg mice had reduced differentiation and mineralization with reduced Alpl and Runx2 transcripts. In conclusion, endogenous EPO-Epor signaling in osteoblasts is important in bone remodeling, particularly trabecular bone and endogenous Epor expression in osteoblasts is required for bone loss accompanying EPO-stimulated erythropoiesis.

1950-P: Fat Mass Affects Metabolic Response to Erythropoietin in Mice

Erythropoietin (EPO) is required for erythrocyte production. However, EPO receptor (EpoR) expression extends beyond erythroid tissue. To assess EPO activity on glucose homeostasis and fat mass accumulation, wild type (WT, C57BL/6) mice, ΔEpoRE mice with EpoR restricted to hematopoietic tissue and ΔEpoRWAT mice with targeted EpoR deletion in fat tissue were fed a high fat diet (HFD, 60% kCal fat) and treated with EPO (3000U/kg 3X per week) or saline for 3 weeks at age 3, 4, and 6 months. EPO increased hematocrit in all mice and improved glucose tolerance when fat mass was less than 35% which included all female mice. In male WT mice EPO improved glucose tolerance and reduced fat mass which at 6 months was 40% on HFD and below 35% with HFD/EPO treatment. In female mice, estrogen interferes with EPO fat mass regulation. EPO treatment did not affect fat mass in ΔEpoRE mice, indicating that EPO regulation of fat mass is a non-hematopoietic response. EPO improved glucose tolerance in female and only age 3 month male ΔEpoRE mice when fat mass was less than 35%. In male ΔEpoRWAT mice, EPO minimally reduced fat mass indicating that EPO fat mass regulation in males is largely a direct fat tissue response. EPO treatment improved glucose tolerance in male ΔEpoRWAT mice when fat mass was below 35% but not at 6 months when fat mass exceeded 40%. These data demonstrate that EPO improved glucose tolerance when fat mass was below 35%, that the sex-dimorphic EPO regulation of fat mass is primarily mediated by EpoR in fat, and that EPO activity in glucose metabolism and fat mass is differentially regulated and does not follow EPO stimulated erythropoiesis. Disclosure H. Rogers: None. C.T. Noguchi: None. Funding National Institutes of Health

Vaccination accelerates hepatic erythroblastosis induced by blood-stage malaria

BackgroundVaccination induces survival of otherwise lethal blood-stage infections of the experimental malaria Plasmodium chabaudi. Blood-stage malaria induces extramedullary erythropoiesis in the liver. This study investigates how vaccination affects the course of malaria-induced expression of erythrocytic genes in the liver.MethodsFemale Balb/c mice were vaccinated at week 3 and week 1 before challenging with 106P. chabaudi-parasitized erythrocytes. The non-infectious vaccine consisted of erythrocyte ghosts isolated from P. chabaudi-infected erythrocytes. Gene expression microarrays and quantitative real-time PCR were used to compare mRNA expression of different erythrocytic genes in the liver of vaccination-protected and non-protected mice during infections on days 0, 1, 4, 8, and 11 p.i.ResultsGlobal transcriptomics analyses reveal vaccination-induced modifications of malaria-induced increases in hepatic gene expression on days 4 and 11 p.i. On these days, vaccination also alters hepatic expression of the erythropoiesis-involved genes Ermap, Kel, Rhd, Rhag, Slc4a1, Gypa, Add2, Ank1, Epb4.1, Epb4.2, Epb4.9, Spta1, Sptb, Tmod1, Ahsp, Acyp1, Gata1, Gfi1b, Tal1, Klf1, Epor, and Cldn13. In vaccination-protected mice, expression of these genes, except Epb4.1, is significantly higher on day 4 p.i. than in un-protected non-vaccinated mice, reaches maximal expression at peak parasitaemia on day 8 p.i., and is slowed down or even decreased towards the end of crisis phase on day 11 p.i.. After day 1 p.i., Epor expression takes about the same course as that of the other erythroid genes. Hepatic expression of Epo, however, is delayed in both vaccinated and non-vaccinated mice for the first 4 days p.i. and is maximal at significantly higher levels in vaccinated mice on day 8 p.i., before declining towards the end of crisis phase on day 11 p.i.ConclusionThe present data indicate that vaccination accelerates malaria-induced erythroblastosis in the liver for 1–2 days. This may contribute to earlier replenishment of peripheral red blood cells by liver-derived reticulocytes, which may favour final survival of otherwise lethal blood-stage malaria, since reticulocytes are not preferred as host cells by P. chabaudi.

Is the erythropoietin receptor the key to the identification of the central macrophage in erythroblastic islands?

Is the erythropoietin receptor the key to the identification of the central macrophage in erythroblastic islands?