Erythropoietin receptor is expressed on human peripheral blood T and B lymphocytes and monocytes and is modulated by recombinant human erythropoietin treatment

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

Background

Erythropoietin 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.

Methods

This 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.

Results

The 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.

Conclusion

The 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.

Infantile Cocktail of Erythropoietin and Melatonin Restores Gait in Adult Rats with Preterm Brain Injury

Cerebral palsy (CP) is the most common cause of physical disability for children worldwide. Many infants and toddlers are not diagnosed with CP until they fail to achieve obvious motor milestones. Currently, there are no effective pharmacologic interventions available for infants and toddlers to substantially improve their trajectory of neurodevelopment. Because children with CP from preterm birth also exhibit a sustained immune system hyper-reactivity, we hypothesized that neuro-immunomodulation with a regimen of repurposed endogenous neurorestorative medications, erythropoietin (EPO) and melatonin (MLT), could improve this trajectory. Thus, we administered EPO + MLT to rats with CP during human infant-toddler equivalency to determine whether we could influence gait patterns in mature animals. After a prenatal injury on embryonic day 18 (E18) that mimics chorioamnionitis at ∼25 weeks human gestation, rat pups were born and raised with their dam. Beginning on postnatal day 15 (P15), equivalent to human infant ∼1 year, rats were randomized to receive either a regimen of EPO + MLT or vehicle (sterile saline) through P20. Gait was assessed in young adult rats at P30 using computerized digital gait analyses including videography on a treadmill. Results indicate that gait metrics of young adult rats treated with an infantile cocktail of EPO + MLT were restored compared to vehicle-treated rats (p < 0.05) and similar to sham controls. These results provide reassuring evidence that pharmacological interventions may be beneficial to infants and toddlers who are diagnosed with CP well after the traditional neonatal window of intervention.

The Effect of Erythropoietin and Its Derivatives on Ischemic Stroke Therapy: A Comprehensive Review

Numerous studies explored the therapeutic effects of erythropoietin (EPO) on neurodegenerative diseases. Few studies provided comprehensive and latest knowledge of EPO treatment for ischemic stroke. In the present review, we introduced the structure, expression, function of EPO, and its receptors in the central nervous system. Furthermore, we comprehensively discussed EPO treatment in pre-clinical studies, clinical trials, and its therapeutic mechanisms including suppressing inflammation. Finally, advanced studies of the therapy of EPO derivatives in ischemic stroke were also discussed. We wish to provide valuable information on EPO and EPO derivatives’ treatment for ischemic stroke for basic researchers and clinicians to accelerate the process of their clinical applications.

Transcriptomic Markers of Recombinant Human Erythropoietin Micro-Dosing in Thoroughbred Horses

Recombinant human erythropoietin (rHuEPO) is a well-known performance enhancing drug in human athletes, and there is anecdotal evidence of it being used in horse racing for the same purpose. rHuEPO, like endogenous EPO, increases arterial oxygen content and thus aerobic power. Micro-doping, or injecting smaller doses over a longer period of time, has become an important concern in both human and equine athletics since it is more difficult to detect. Horses offer an additional challenge of a contractile spleen, thus large changes in the red blood cell mass occur naturally. To address the challenge of detecting rHuEPO doping in horse racing, we determined the transcriptomic effects of rHuEPO micro-dosing over seven weeks in exercised Thoroughbreds. RNA-sequencing of peripheral blood mononuclear cells isolated at several time points throughout the study identified three transcripts (C13H16orf54, PUM2 and CHTOP) that were significantly (PFDR < 0.05) different between the treatment groups across two or three time point comparisons. PUM2 and CHTOP play a role in erythropoiesis while not much is known about C13H16orf54, but it is primarily expressed in whole blood. However, gene expression differences were not large enough to detect via RT-qPCR, thereby precluding their utility as biomarkers of micro-doping.

Granulocytes Negatively Regulate Secretion of Transforming Growth Factor β1 by Bone Marrow Mononuclear Cells via Secretion of Erythropoietin Receptors in the Milieu

In my previous study, I demonstrated that bone marrow-derived mononuclear cells (BM MNCs) secrete copious amounts of Transforming Growth Factor β1 (TGFβ1) in response to erythropoietin (EPO). In this study, I investigated the principal cell type involved in the process. I found that a large percentage of various marrow cells, but not their mature counterparts present in the peripheral blood, express EPO-receptors (EPO-R). Cell depletion experiments showed that depletion of Glycophorin positive erythroblasts and CD41⁺ megakaryocytes - the prime suspects - did not affect the EPO-mediated TGFβ1 secretion by the BM MNCs. However, individual depletion of CD2⁺ T lymphocytes, CD14⁺ monocyte/macrophages, and CD19⁺ B cells affected the TGFβ1 secretion by EPO-primed MNCs: depletion of CD2⁺ cells had the most striking effect. Unexpectedly, and most interestingly, depletion of CD15⁺ granulocytes led to a significant increase in the TGFβ1 secretion by both naïve and EPO-primed BM MNCs, suggesting that these cells negatively regulate the process. Mechanistically, I show that the CD15⁺ cells exert this regulatory effect via secretion of both full-length and soluble EPO-R in the milieu. Overall my results, for the first time, unravel an in-built regulatory mechanism prevailing in the BM microenvironment that regulates the secretion of TGFβ1 by controlling EPO-EPO-R interaction.My data could be relevant in understanding the pathophysiology of several conditions associated with deregulated production of TGFβ1 in the marrow compartment.

Age and genotype dependent erythropoietin protection in COVID-19

Erythropoietin (EPO) is the main mediator of erythropoiesis and an important tissue protective hormone that appears to mediate an ancestral neuroprotective innate immune response mechanism at an early age. When the young brain is threatened-prematurity, neonatal hyperbilirubinemia, malaria- EPO is hyper-secreted disproportionately to any concurrent anemic stimuli. Under eons of severe malarial selection pressure, neuroprotective EPO augmenting genetic determinants such as the various hemoglobinopathies, and the angiotensin converting enzyme (ACE) I/D polymorphism, have been positively selected. When malarial and other cerebral threats abate and the young child survives to adulthood, EPO subsides. Sustained high ACE and angiotensin II (Ang II) levels through the ACE D allele in adulthood may then become detrimental as witnessed by epidemiological studies. The ubiquitous renin angiotensin system (RAS) influences the α-klotho/fibroblast growth factor 23 (FGF23) circuitry, and both are interconnected with EPO. Here we propose that at a young age, EPO augmenting genetic determinants through ACE D allele elevated Ang II levels in some or HbE/beta thalassemia in others would increase EPO levels and shield against coronavirus disease 2019, akin to protection from malaria and dengue fever. Human evolution may use ACE2 as a “bait” for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) to gain cellular entry in order to trigger an ACE/ACE2 imbalance and stimulate EPO hypersecretion using tissue RAS, uncoupled from hemoglobin levels. In subjects without EPO augmenting genetic determinants at any age, ACE2 binding and internalization upon SARS-CoV-2 entry would trigger an ACE/ACE2 imbalance, and Ang II oversecretion leading to protective EPO stimulation. In children, low nasal ACE2 Levels would beneficially augment this imbalance, especially for those without protective genetic determinants. On the other hand, in predisposed adults with the ACE D allele, ACE/ACE2 imbalance, may lead to uncontrolled RAS overactivity and an Ang II induced proinflammatory state and immune dysregulation, with interleukin 6 (IL-6), plasminogen activator inhibitor, and FGF23 elevations. IL-6 induced EPO suppression, aggravated through co-morbidities such as hypertension, diabetes, obesity, and RAS pharmacological interventions may potentially lead to acute respiratory distress syndrome, cytokine storm and/or autoimmunity. HbE/beta thalassemia carriers would enjoy protection at any age as their EPO stimulation is uncoupled from the RAS system. The timely use of rhEPO, EPO analogs, acetylsalicylic acid, bioactive lipids, or FGF23 antagonists in genetically predisposed individuals may counteract those detrimental effects.

Erythropoietin in Lupus: Unanticipated Immune Modulating Effects of a Kidney Hormone

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disease with variable clinical presentation, typically characterized by a relapsing-remitting course. SLE has a multifactorial pathogenesis including genetic, environmental, and hormonal factors that lead to loss of tolerance against self-antigens and autoantibody production. Mortality in SLE patients remains significantly higher than in the general population, in part because of the limited efficacy of available treatments and the associated toxicities. Therefore, novel targeted therapies are urgently needed to improve the outcomes of affected individuals. Erythropoietin (EPO), a kidney-produced hormone that promotes red blood cell production in response to hypoxia, has lately been shown to also possess non-erythropoietic properties, including immunomodulatory effects. In various models of autoimmune diseases, EPO limits cell apoptosis and favors cell clearance, while reducing proinflammatory cytokines and promoting the induction of regulatory T cells. Notably, EPO has been shown to reduce autoimmune response and decrease disease severity in mouse models of SLE. Herein, we review EPO's non-erythropoietic effects, with a special focus on immune modulating effects in SLE and its potential clinical utility.

CHBP induces stronger immunosuppressive CD127+ M-MDSC via erythropoietin receptor

Erythropoietin (EPO) is not only an erythropoiesis hormone but also an immune-regulatory cytokine. The receptors of EPO (EPOR)2 and tissue-protective receptor (TPR), mediate EPO's immune regulation. Our group firstly reported a non-erythropoietic peptide derivant of EPO, cyclic helix B peptide (CHBP), which could inhibit macrophages inflammation and dendritic cells (DCs) maturation. As a kind of innate immune regulatory cell, myeloid-derived suppressor cells (MDSCs) share a common myeloid progenitor with macrophages and DCs. In this study, we investigated the effects on MDSCs differentiation and immunosuppressive function via CHBP induction. CHBP promoted MDSCs differentiate toward M-MDSCs with enhanced immunosuppressive capability. Infusion of CHBP-induced M-MDSCs significantly prolonged murine skin allograft survival compared to its counterpart without CHBP stimulation. In addition, we found CHBP increased the proportion of CD11b+Ly6G-Ly6Chigh CD127+ M-MDSCs, which exerted a stronger immunosuppressive function compared to CD11b+Ly6G-Ly6Chigh CD127- M-MDSCs. In CHBP induced M-MDSCs, we found that EPOR downstream signal proteins Jak2 and STAT3 were upregulated, which had a strong relationship with MDSC function. In addition, CHBP upregulated GATA-binding protein 3 (GATA-3) protein translation level, which was an upstream signal of CD127 and regulator of STAT3. These effects of CHBP could be reversed if Epor was deficient. Our novel findings identified a new subset of M-MDSCs with better immunosuppressive capability, which was induced by the EPOR-mediated Jak2/GATA3/STAT3 pathway. These results are beneficial for CHBP clinical translation and MDSC cell therapy in the future.

Exploration of the relationship between tumor mutation burden and immune infiltrates in colon adenocarcinoma

Background: Tumor mutation burden (TMB) was correlated with the immunotherapeutic response in various malignancies. We aimed to evaluate the TMB immune signature in colon adenocarcinoma (COAD). Methods: Gene expression profile, mutation and clinical data of COAD patients were obtained from The Cancer Genome Atlas (TCGA) database. The samples were divided into high and low TMB level groups to identify differentially expressed genes (DEGs). Functional enrichments analyzes were performed to identify the biological functions of the DEGs. Then, immune cell infiltration signatures were calculated by the CIBERSORT algorithm. Finally, Cox proportional hazard model was constructed to estimate the prognostic value of the identified immune-related genes. Results: Gene set enrichment analysis in the high-TMB level group showed that DEGS were enriched in immune-related pathways, such as antigen processing and presentation, Toll-like receptor signaling and natural killer cell-mediated cytotoxicity. A higher infiltration level of CD8+ T cells, CD4+ T cells, activated NK cells , M1 Macrophages and T follicular helper cells was observed in the high-TMB level group. Furthermore, a Cox regression model combined with survival analysis based on the expression level of four identified prognostic genes was constructed, validated anf revealed that higher risk-score levels conferred poor survival outcomes in COAD patients. Conclusions: Our data demonstrate that the high TMB levels are associated with an immune signature in COAD and deepen the molecular understanding of TMB function in tumor immunotherapy.

Immune Dysfunction in Uremia 2020

Cardiovascular disease and infections are major causes for the high incidence of morbidity and mortality of patients with chronic kidney disease. Both complications are directly or indirectly associated with disturbed functions or altered apoptotic rates of polymorphonuclear leukocytes, monocytes, lymphocytes, and dendritic cells. Normal responses of immune cells can be reduced, leading to infectious diseases or pre-activated/primed, giving rise to inflammation and subsequently to cardiovascular disease. This review summarizes the impact of kidney dysfunction on the immune system. Renal failure results in disturbed renal metabolic activities with reduced renin, erythropoietin, and vitamin D production, which adversely affects the immune system. Decreased kidney function also leads to reduced glomerular filtration and the retention of uremic toxins. A large number of uremic toxins with detrimental effects on immune cells have been identified. Besides small water-soluble and protein-bound compounds originating from the intestinal microbiome, several molecules in the middle molecular range, e.g., immunoglobulin light chains, retinol-binding protein, the neuropeptides Met-enkephalin and neuropeptide Y, endothelin-1, and the adipokines leptin and resistin, adversely affect immune cells. Posttranslational modifications such as carbamoylation, advanced glycation products, and oxidative modifications contribute to uremic toxicity. Furthermore, high-density lipoprotein from uremic patients has an altered protein profile and thereby loses its anti-inflammatory properties.

Erythropoietin and its derivatives: from tissue protection to immune regulation

Erythropoietin (EPO) is an evolutionarily conserved hormone well documented for its erythropoietic role via binding the homodimeric EPO receptor (EPOR)₂. In past decades, evidence has proved that EPO acts far beyond erythropoiesis. By binding the tissue-protective receptor (TPR), EPO suppresses proinflammatory cytokines, protects cells from apoptosis and promotes wound healing. Very recently, new data revealed that TPR is widely expressed on a variety of immune cells, and EPO could directly modulate their activation, differentiation and function. Notably, nonerythropoietic EPO derivatives, which mimic the structure of helix B within EPO, specifically bind TPR and show great potency in tissue protection and immune regulation. These small peptides prevent the cardiovascular side effects of EPO and are promising as clinical drugs. This review briefly introduces the receptors and tissue-protective effects of EPO and its derivatives and highlights their immunomodulatory functions and application prospects.

Erythropoietin, a multifaceted protein with innate and adaptive immune modulatory activity

Erythropoietin (EPO) is a glycoprotein produced mainly by the adult kidney in response to hypoxia and is the crucial regulator of red blood cell production. EPO receptors (EPORs), however, are not confined to erythroid cells, but are expressed by many organs including the heart, brain, retina, pancreas, and kidney, where they mediate EPO-induced, erythropoiesis-independent, tissue-protective effects. Some of these tissues also produce and locally release small amounts of EPO in response to organ injury as a mechanism of self-repair. Growing evidence shows that EPO possesses also important immune-modulating effects. Monocytes can produce EPO, and autocrine EPO/EPOR signaling in these cells is crucial in maintaining immunologic self-tolerance. New data in mice and humans also indicate that EPO has a direct inhibitory effect on effector/memory T cells, while it promotes formation of regulatory T cells. This review examines the nonerythropoietic effects of EPO, with a special emphasis on its modulating activity on innate immune cells and T cells and on how it affects transplant outcomes.

Clinical and Pathological Significance of Autoantibodies to Erythropoietin Receptor in Type 2 Diabetic Patients With CKD

Introduction

We examined the impact of autoantibodies on the erythropoietin receptor (EPOR) in type 2 diabetic patients with chronic kidney disease (CKD).

Methods

A total of 112 Japanese patients with type 2 diabetes who had CKD were enrolled in this study and followed for a mean of 45 months. Sera from these patients were screened for anti-EPOR antibodies using enzyme-linked immunosorbent assays.

Results

Anti-EPOR antibodies were detected in 26 patients (23%). Anti-EPOR antibodies were associated with low hemoglobin concentrations and decreased renal function. In patients with biopsy-proven diabetic nephropathy, anti-EPOR antibodies were associated with increased levels of interstitial inflammation. A decrease in renal function was observed more frequently in patients with antibodies than in those without antibodies, and the presence of the antibodies together with well-known clinical parameters, including proteinuria and low glomerular filtration rate, was a significant risk factor for end-stage renal disease. In human tubular epithelial HK-2 cells, IgG fractions containing anti-EPOR antibodies upregulated the expression of monocyte chemoattractant protein-1 mRNA under a high concentration of glucose.

Conclusion

Anti-EPOR antibodies might be involved in the progression of renal lesions and in the impaired erythropoiesis in type 2 diabetic patients with CKD. Furthermore, the presence of anti-EPOR antibodies may be an additional predictor for end-stage renal disease in type 2 diabetes.

Erythropoietin increases macrophage-mediated T cell suppression

Erythropoietin (EPO), used to treat anemia in cancer patients, has been reported to accelerate tumor progression and increase mortality. Research of the mechanism for this effect has focused upon EPOR expression by tumor cells. We model the high macrophage to lymphocyte ratio found in tumor microenvironments (TMEs) by culturing peritoneal cavity (PerC) cells that naturally have a high macrophage to T cell ratio. Following TCR ligation, C57BL/6J PerC T cell proliferation is suppressed due to IFNγ-triggered inducible nitric oxide synthase (iNOS) expression. EPO was tested in the PerC culture model and found to increase T cell suppression. This effect could be abrogated by inhibiting iNOS by enzyme inhibition, genetic ablation, or blocking IFNγ signaling. Flow cytometry revealed the EPOR on CD11b(+)F4/80(+) macrophages. These results suggest that EPO could increase T cell suppression in the TME by acting directly on macrophages.

Effects of erythropoietin on adipose tissue: a possible strategy in refilling

Background:

The increased resorption and the difficulty of the fat graft take following autologous fat transplantation procedure are associated with reduced fat tissue revascularization and increased apoptosis of adipose cells. We suppose that the lipofilling procedure induces an inflammatory environment within the fat graft mass, whose evolution influences the efficacy of autologous fat graft survival. Erythropoietin (EPO) is a glycoprotein hormone known to exert angiogenetic and anti-inflammatory effects; therefore, our purpose was to investigate its reaction with adipose tissue used in lipofilling.

Methods:

Fat masses were harvested using manual suction lipectomy and then seeded on dishes in appropriate culture and treated for 3 weeks with 3 doses of EPO. CD31 and CD68 immunohistochemistry was used to identify microvessels and several infiltrating leukocyte cells.

Results:

Following EPO administration, we have detected an increase in the number of CD31-positive microvessel endothelium cells and CD31-positive small leukocytes and a reduction of CD68-positive cells. These effects were more conspicuous following higher EPO dose.

Conclusions:

Our findings evidence EPO treatment as a useful strategy to sustain the revascularization of grafted tissue and to reduce its inflammatory state.

Immunosuppressive effects of erythropoietin on human alloreactive T cells

Correction of anemia with erythropoietin (EPO) is associated with improved kidney transplant outcomes. Emerging evidence, predominantly from animal models, indicates that these observations may be erythropoiesis-independent and that EPO exhibits immunosuppressive properties. We examined the effects of EPO on human T-cell alloimmunity by first documenting that CD4(+) and CD8(+) T cells express EPO receptor (EPO-R) on their surfaces. In mixed lymphocyte reactions, EPO induced a dose-dependent decrease in allogeneic CD4(+) T-cell proliferation (EPO 1000 U/ml: 44.6%±22.9% of vehicle, P<0.05; 2000 U/ml: 11.1%±4% of vehicle, P<0.001) without inducing cell death. The effects required signals transmitted directly through the EPO-R expressed on T cells, resulting in diminished Th1 differentiation without effects on regulatory T-cell induction. Mechanistic studies revealed that EPO prevented IL-2-induced proliferation by uncoupling IL-2 receptor signaling, inhibiting phosphorylation of the intracellular intermediaries AKT and extracellular signal-regulated kinase that are known to mediate T-cell expansion. EPO treatment reduced expansion of human naïve CD4(+) T cells after adoptive transfer into NOD scid γc(null) mouse recipients, verifying the effects in vivo. Although activated T cells expressed CD131, an alternative EPO receptor, addition of a specific CD131 agonist peptide, ARA290, did not alter T-cell proliferation or cytokine production. Our findings link EPO-R signaling on T cells to inhibition of T-cell immunity, providing one mechanism that could explain the observed protective effects of EPO in kidney transplant recipients.

The influence of the pleiotropic action of erythropoietin and its derivatives on nephroprotection

Erythropoietin (EPO) is traditionally described as a hematopoietic cytokine or growth hormone regulating proliferation, differentiation, and survival of erythroid progenitors. The use of EPO in patients with chronic kidney disease (CKD) was a milestone achievement in the treatment of anemia. However, EPO involves some degree of risk, which increases with increasing hemoglobin levels. A growing number of studies have assessed the renoprotective effects of EPO in acute kidney injury (AKI) or CKD. Analysis of the biological effects of erythropoietin and pathophysiology of CKD in these studies suggests that treatment with erythropoiesis-stimulating agents (ESAs) may exert renoprotection by pleiotropic actions on several targets and directly or indirectly slow the progression of CKD. By reducing ischemia and oxidative stress or strengthening anti-apoptotic processes, EPO may prevent the development of interstitial fibrosis and the destruction of tubular cells. Furthermore, it could have a direct protective impact on the integrity of the interstitial capillary network through its effects on endothelial cells and promotion of vascular repair, or modulate inflammation response. Thus, it is biologically plausible to suggest that correcting anemia with ESAs could slow the progression of CKD.                         The aim of this article is to discuss these possible renoprotection mechanisms and provide a comprehensive overview of erythropoietin and its derivatives.

Changes in the Expression of Transcription Factors Involved in Modulating the Expression of EPO-R in Activated Human CD4-Positive Lymphocytes

We have recently described the presence of the erythropoietin receptor (EPO-R) on CD4⁺ lymphocytes and demonstrated that its expression increases during their activation, reaching a level reported to be typical for erythroid progenitors. This observation suggests that EPO-R expression is modulated during lymphocyte activation, which may be important for the cells’ function. Here we investigated whether the expression of GATA1, GATA3 and Sp1 transcription factors is correlated with the expression of EPO-R in human CD4⁺ lymphocytes stimulated with monoclonal anti-CD3 antibody. The expression of GATA1, GATA3 and Sp1 transcription factors in CD4⁺ cells was estimated before and after stimulation with anti-CD3 antibody by Western Blot and flow cytometry. The expression of EPO-R was measured using real-time PCR and flow cytometry. There was no change in the expression of GATA1 and GATA3 in CD4⁺ lymphocytes after stimulation with anti-CD3 antibody. However, stimulation resulted in the significantly increased expression of the Sp1 factor. CD4⁺ lymphocytes stimulated with anti-CD3 antibody exhibited an increase in both the expression level of EPOR gene and the number of EPO-R molecules on the cells’ surface, the latter being significantly correlated with the increased expression of Sp1. Sp1 is noted to be the single transcription factor among the ones studied whose level changes as a result of CD4⁺ lymphocyte stimulation. It seems that Sp1 may significantly affect the number of EPO-R molecules present on the surface of activated CD4⁺ lymphocytes.

The influence of recombinant human erythropoietin on apoptosis and cytokine production of CD4+ lymphocytes from hemodialyzed patients

Recombinant human erythropoietin (rhEPO) treatment of hemodialyzed (HD) patients normalizes the altered phenotype of CD4⁺ lymphocytes and restores the balance of Th1/Th2 cytokines. We decided to test how the presence of rhEPO in cell culture modulates cytokine production of CD4⁺ lymphocytes in HD patients with stable hemoglobin level and expression of activation antigens of stimulated CD4⁺ lymphocytes similar to those observed in healthy individuals. We also tested whether the presence of rhEPO in cell culture protects stimulated CD4⁺ lymphocytes of HD patients from apoptosis. Peripheral blood mononuclear cells (PBMC) of HD patients were stimulated with an immobilized anti-CD3 antibody with or without addition of rhEPO. The percentage of apoptotic CD4⁺ lymphocytes and the level of Th1/Th2 cytokines in culture supernatants were measured with flow cytometry. HD patients showed a decrease in the percentage of apoptotic CD4⁺ cells after stimulation with the anti-CD3 antibody combined with rhEPO. The level of IFN-γ and IL-10 was increased while the level of TNF-α was decreased in the presence of rhEPO in cell culture from HD patients. These results confirm the role of rhEPO signaling in T lymphocytes of HD patients.

Short-term erythropoietin treatment does not substantially modulate monocyte transcriptomes of patients with combined heart and renal failure

BACKGROUND

Combined heart and renal failure is associated with high cardiovascular morbidity and mortality. Anti-oxidant and anti-inflammatory, non-hematopoietic effects of erythropoietin (EPO) treatment have been proposed. Monocytes may act as biosensors of the systemic environment. We hypothesized that monocyte transcriptomes of patients with cardiorenal syndrome (CRS) reflect the pathophysiology of the CRS and respond to short-term EPO treatment at a recommended dose for treatment of renal anemia.

METHODS

Patients with CRS and anemia (n = 18) included in the EPOCARES trial were matched to healthy controls (n = 12). Patients were randomized to receive 50 IU/kg/week EPO or not. RNA from CD14(+)-monocytes was subjected to genome wide expression analysis (Illumina) at baseline and 18 days (3 EPO injections) after enrolment. Transcriptomes from patients were compared to healthy controls and effect of EPO treatment was evaluated within patients.

RESULTS

In CRS patients, expression of 471 genes, including inflammation and oxidative stress related genes was different from healthy controls. Cluster analysis did not separate patients from healthy controls. The 6 patients with the highest hsCRP levels had more differentially expressed genes than the 6 patients with the lowest hsCRP levels. Analysis of the variation in log(2) ratios of all individual 18 patients indicated that 4 of the 18 patients were different from the controls, whereas the other 14 were quite similar. After short-term EPO treatment, every patient clustered to his or her own baseline transcriptome. Two week EPO administration only marginally affected expression profiles on average, however, individual gene responses were variable.

CONCLUSIONS

In stable, treated CRS patients with mild anemia, monocyte transcriptomes were modestly altered, and indicated imprints of inflammation and oxidative stress. EPO treatment with a fixed dose has hematopoietic effects, had no appreciable beneficial actions on monocyte transcription profiles, however, could also not be associated with undesirable transcriptional responses.