Carbamylated erythropoietin promotes neurite outgrowth and neuronal spine formation in association with CBP/p300

Carbamoylated Erythropoietin Rescues Autism-Relevant Social Deficits in BALB/cJ Mice

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects over 2% of the population worldwide and is characterized by repetitive behaviors, restricted areas of interest, deficits in social communication, and high levels of anxiety. Currently, there are no known effective treatments for the core features of ASD. The previous literature has established erythropoietin (EPO) as a promising antidepressant, working as a potent neurogenic and neurotrophic agent with hematopoietic side effects. Carbamoylated erythropoietin (CEPO), a chemically engineered non-hematopoietic derivative of EPO, appears to retain the neuroprotective factors of EPO without the hematologic properties. Recent evidence shows that CEPO corrects stress-related depressive behaviors in BALB/cJ (BALB) mice, which also have face validity as an ASD mouse model. We investigated whether CEPO can recover deficient social and anxiety-related behavioral deficits compared to C57BL/6J controls. After administering CEPO (40 μg/kg in phosphate-buffered saline) or vehicle over 21 days, we analyzed the mice's performance in the three-chamber social approach, the open field, the elevated plus maze, and the Porsolt's forced swim tasks. CEPO appeared to correct sociability in the three-chamber social approach task to C57 levels, increasing the amount of time the mice interacted with novel, social mice overall rather than altering the overall amount of exploratory activity in the maze. Consistent with this finding, there was no concomitant increase in the distance traveled in the open field, nor were there any alterations in the anxiety-related measures in the task. On the other hand, CEPO administration improved exploratory behavior in the elevated plus maze. This study marks the first demonstration of the benefits of a non-erythropoietic EPO derivative for social behavior in a mouse model of autism and merits further investigation into the mechanisms by which this action occurs.

Genetic Deficiency of p53 Leads to Structural, Functional, and Synaptic Deficits in Primary Somatosensory Cortical Neurons of Adult Mice

The tumor suppressor p53 plays a crucial role in embryonic neuron development and neurite growth, and its involvement in neuronal homeostasis has been proposed. To better understand how the lack of the p53 gene function affects neuronal activity, spine development, and plasticity, we examined the electrophysiological and morphological properties of layer 5 (L5) pyramidal neurons in the primary somatosensory cortex barrel field (S1BF) by using in vitro whole-cell patch clamp and in vivo two-photon imaging techniques in p53 knockout (KO) mice. We found that the spiking frequency, excitatory inputs, and sag ratio were decreased in L5 pyramidal neurons of p53KO mice. In addition, both in vitro and in vivo morphological analyses demonstrated that dendritic spine density in the apical tuft is decreased in L5 pyramidal neurons of p53KO mice. Furthermore, chronic imaging showed that p53 deletion decreased dendritic spine turnover in steady-state conditions, and prevented the increase in spine turnover associated with whisker stimulation seen in wildtype mice. In addition, the sensitivity of whisker-dependent texture discrimination was impaired in p53KO mice compared with wildtype controls. Together, these results suggest that p53 plays an important role in regulating synaptic plasticity by reducing neuronal excitability and the number of excitatory synapses in S1BF.

Erythropoietin and derivatives: Potential beneficial effects on the brain

Erythropoietin (Epo), the main erythropoiesis-stimulating factor widely prescribed to overcome anemia, is also known nowadays for its cytoprotective action on non-hematopoietic tissues. In this context, Epo showed not only its ability to cross the blood-brain barrier, but also its expression in the brain of mammals. In clinical trials, recombinant Epo treatment has been shown to stimulate neurogenesis; improve cognition; and activate antiapoptotic, antioxidant, and anti-inflammatory signaling pathways. These mechanisms, proposed to characterize a neuroprotective property, opened new perspectives on the Epo pharmacological potencies. However, many questions arise about a possible physiological role of Epo in the central nervous system (CNS) and the factors or environmental conditions that induce its expression. Although Epo may be considered a strong candidate to be used against neuronal damage, long-term treatments, particularly when high Epo doses are needed, may induce thromboembolic complications associated with increases in hematocrit and blood viscosity. To avoid these adverse effects, different Epo analogs without erythropoietic activity but maintaining neuroprotection ability are currently being investigated. Carbamylated erythropoietin, as well as alternative molecules like Epo fusion proteins and partial peptides of Epo, seems to match this profile. This review will focus on the discussion of experimental evidence reported in recent years linking erythropoietin and CNS function through investigations aimed at finding benefits in the treatment of neurodegenerative diseases. In addition, it will review the proposed mechanisms for novel derivatives which may clarify and, eventually, improve the neuroprotective action of Epo.

Novel erythropoietin-based therapeutic candidates with extra N-glycan sites that block hematopoiesis but preserve neuroplasticity

Neurological disorders affect millions of people causing behavior-cognitive disabilities. Nowadays they have no effective treatment. Human erythropoietin (hEPO) has been clinically used because of its neurotrophic and cytoprotective properties. However, the erythropoietic activity (EA) should be considered as a side effect. Some analogs like non-sialylated EPO, carbamylated EPO, or EPO peptides have been developed showing different weaknesses: erythropoiesis preservation, low stability, potential immunogenicity, or fast clearance. Herein, we used a novel strategy that blocks the EA but preserves hEPO neurobiological actions. N-glycoengineering was accomplished to add a new glycosylation site within the hEPO sequence responsible for its EA. hEPO-derivatives were produced by CHO.K1 cells, affinity-purified and functionally analyzed studying their in vitro and in vivo EA, their in vitro neuronal plasticity in hippocampal neurons and their neuroprotective action by rescuing hippocampal neurons from apoptosis. Muteins Mut 45_47 (K45 > N45 + N47 > T47), Mut 104 (S104 > N104), and Mut 151_153 (G151 > N151 + K153 > T153) lost their EA but preserved their neuroprotection activity and enhanced neuroplasticity more efficiently than hEPO. Interestingly, Mut 45_47 resulted in a promising candidate to explore as neurotherapeutic considering not only its biopotency but also its pharmacokinetic potential due to the hyperglycosylation.

Mitochondrial Metabolism as Target of the Neuroprotective Role of Erythropoietin in Parkinson's Disease

Existing therapies for Parkinson's disease (PD) are only symptomatic. As erythropoietin (EPO) is emerging for its benefits in neurodegenerative diseases, here, we test the protective effect driven by EPO in in vitro (SH-SY5Y cells challenged by MPP⁺) and in vivo (C57BL/6J mice administered with MPTP) PD models. EPO restores cell viability in both protective and restorative layouts, enhancing the dopaminergic recovery. Specifically, EPO rescues the PD-induced damage to mitochondria, as shown by transmission electron microscopy, Mitotracker assay and PINK1 expression. Moreover, EPO promotes a rescue of mitochondrial respiration while markedly enhancing the glycolytic rate, as shown by the augmented extracellular acidification rate, contributing to elevated ATP levels in MPP⁺-challenged cells. In PD mice, EPO intrastriatal infusion markedly improves the outcome of behavioral tests. This is associated with the rescue of dopaminergic markers and decreased neuroinflammation. This study demonstrates cellular and functional recovery following EPO treatment, likely mediated by the 37 Kda isoform of the EPO-receptor. We report for the first time, that EPO-neuroprotection is exerted through restoring ATP levels by accelerating the glycolytic rate. In conclusion, the redox imbalance and neuroinflammation associated with PD may be successfully treated by EPO.

Transcriptome profiles of sturgeon lateral line electroreceptor and mechanoreceptor during regeneration

Background

The electrosensory ampullary organs (AOs) and mechanosensory neuromasts (NMs) found in sturgeon and some other non-neopterygian fish or amphibians are both originated from lateral line placodes. However, these two sensory organs have characteristic morphological and physiological differences. The molecular mechanisms for the specification of AOs and NMs are not clearly understood.

Results

We sequenced the transcriptome for neomycin treated sturgeon AOs and NMs in the early regeneration stages, and de novo assembled a sturgeon transcriptome. By comparing the gene expression differences among untreated AOs, NMs and general epithelia (EPs), we located some specific genes for these two sensory organs. In sturgeon lateral line, the voltage-gated calcium channels and voltage-gated potassium channels were predominant calcium and potassium channel subtypes, respectively. And by correlating gene expression with the regeneration process, we predicated several candidate key transcriptional regulation related genes might be involved in AOs and NMs regeneration.

Conclusions

Genes with specific expression in the two lateral line sensory organs suggests their important roles in mechanoreceptor and electroreceptor formation. The candidate transcriptional regulation related genes may be important for mechano- and electro- receptor specification, in a “dosage-related” manner. These results suggested the molecular basis for specification of these two sensory organs in sturgeon.

Genome Wide Analysis Points towards Subtype-Specific Diseases in Different Genetic Forms of Amyotrophic Lateral Sclerosis

Amyotropic lateral sclerosis (ALS) is a lethally progressive and irreversible neurodegenerative disease marked by apparent death of motor neurons present in the spinal cord, brain stem and motor cortex. While more and more gene mutants being established for genetic ALS, the vast majority suffer from sporadic ALS (>90%). It has been challenging, thus, to model sporadic ALS which is one reason why the underlying pathophysiology remains elusive and has stalled the development of therapeutic strategies of this progressive motor neuron disease. To further unravel these pathological signaling pathways, human induced pluripotent stem cell (hiPSCs)-derived motor neurons (MNs) from FUS- and SOD1 ALS patients and healthy controls were systematically compared to independent published datasets. Here through this study we created a gene profile of ALS by analyzing the DEGs, the Kyoto encyclopedia of Genes and Genomes (KEGG) pathways, the interactome and the transcription factor profiles (TF) that would identify altered molecular/functional signatures and their interactions at both transcriptional (mRNAs) and translational levels (hub proteins and TFs). Our findings suggest that FUS and SOD1 may develop from dysregulation in several unique pathways and herpes simplex virus (HSV) infection was among the topmost predominant cellular pathways connected to FUS and not to SOD1. In contrast, SOD1 is mainly characterized by alterations in the metabolic pathways and alterations in the neuroactive-ligand-receptor interactions. This suggests that different genetic ALS forms are singular diseases rather than part of a common spectrum. This is important for patient stratification clearly pointing towards the need for individualized medicine approaches in ALS.

Erythropoietin induces synaptogenesis and neurite repair after hypoxia ischemia-mediated brain injury in neonatal rats

The memory dysfunction is one of the disastrous outcomes for perinatal hypoxia ischemia. Erythropoietin (EPO) has been demonstrated as a neuroprotective agent with multiple effects in a series of neurological diseases. We hypothesized that disruption of neural network including synapses and neurites would contribute to memory dysfunction induced by hypoxia ischemia. The aim of the present study was to elucidate the involvement of EPO on synaptogenesis and neurite repair following perinatal hypoxia ischemia. Using a neonatal hypoxia ischemia rat model, we found that EPO rescued hypoxia ischemia-induced decrease of synaptic proteins including Synapsin1 and PSD95 rather than GluR1 in the cortex and hippocampus. In addition, EPO reduced the expression of APP (an axonal injury marker), induced the expression of microtubule-associated protein MAP-2 (a dendritic marker), and restored axonal density after hypoxia ischemia. These changes contributed to improving electrophysiological properties of synapses and spatial memory performance. In summary, our data revealed an important role of EPO in synaptogenesis and neurite repair, providing a new insight into cellular mechanisms underlying cognitive and memory dysfunction associated with perinatal hypoxia ischemia.

Carbamoylated erythropoietin induces a neurotrophic gene profile in neuronal cells

Erythropoietin (EPO), a cytokine molecule, is best-known for its role in erythropoiesis. Preclinical studies have demonstrated that EPO has robust neuroprotective effects that appear to be independent of erythropoiesis. It is also being clinically tested for the treatment of neuropsychiatric illnesses due to its behavioral actions. A major limitation of EPO is that long-term administration results in excessive red blood cell production and increased blood viscosity. A chemical modification of EPO, carbamoylated erythropoietin (CEPO), reproduces the behavioral response of EPO in animal models but does not stimulate erythropoiesis. The molecular mechanisms involved in the behavioral effects of CEPO are not known. To obtain molecular insight we examined CEPO induced gene expression in neuronal cells. PC-12 cells were treated with CEPO followed by genome-wide microarray analysis. We investigated the functional significance of the gene profile by unbiased bioinformatics analysis. The Ingenuity pathway analysis (IPA) software was employed. The results revealed activation of functions such as neuronal number and long-term potentiation. Regulated signaling cascades included categories such as neurotrophin, CREB, NGF and synaptic long-term potentiation signaling. Some of the regulated genes from these pathways are CAMKII, EGR1, FOS, GRIN1, KIF1B, NOTCH1. We also comparatively examined EPO and CEPO-induced gene expression for a subset of genes in the rat dentate gyrus. The CEPO gene profile shows the induction of genes and signaling cascades that have roles in neurogenesis and memory formation, mechanisms that can produce antidepressant and cognitive function enhancing activity.

Carbamylated Erythropoietin Decreased Proliferation and Neurogenesis in the Subventricular Zone, but Not the Dentate Gyrus, After Irradiation to the Developing Rat Brain

Cranial radiotherapy for pediatric brain tumors causes progressive, debilitating late effects, including cognitive decline. Erythropoietin (EPO) has been shown to be neuroprotective and to promote neuroregeneration. Carbamylated erythropoietin (CEPO) retains the protective properties of EPO but is not erythrogenic. To study the effects of CEPO on the developing brain exposed to radiotherapy, a single irradiation (IR) dose of 6 Gy was administered to the brains of postnatal day 9 (P9) rats, and CEPO (40 μg/kg s.c.) was injected on P8, P9, P11, P13, and P15. To examine proliferation, 5-Bromo-2-deoxyuridine (BrdU) was injected on P15, P16, and P17. CEPO administration did not affect BrdU incorporation in the granule cell layer (GCL) of the hippocampus or in the subventricular zone (SVZ) as quantified 7 days after the last BrdU injection, whereas IR decreased BrdU incorporation in the GCL and SVZ by 63% and 18%, respectively. CEPO did not affect BrdU incorporation in the GCL of irradiated brains, although it was reduced even further (to 31%) in the SVZ. To evaluate the effect of CEPO on neurogenesis, BrdU/doublecortin double-positive cells were quantified. CEPO did not affect neurogenesis in non-irradiated brains, whereas IR decreased neurogenesis by 58% in the dentate gyrus (DG) but did not affect it in the SVZ. In the DG, CEPO did not affect the rate of neurogenesis following IR, whereas in the SVZ, the rate decreased by 30% following IR compared with the rate in vehicle-treated rats. Neither CEPO nor IR changed the number of microglia. In summary, CEPO did not promote neurogenesis in non-irradiated or irradiated rat brains and even aggravated the decreased neurogenesis in the SVZ. This raises concerns regarding the use of EPO-related compounds following radiotherapy.

Decoding Common Features of Neurodegenerative Disorders: From Differentially Expressed Genes to Pathways

BACKGROUND

Neurodegeneration is a progressive/irreversible loss of neurons, building blocks of our nervous system. Their degeneration gradually collapses the entire structural and functional system manifesting in myriads of clinical disorders categorized as Neurodegenerative Disorders (NDs) such as Alzheimer's Disease, (AD), Parkinson's Disease (PD), Frontotemporal Dementia (FTD) and Amyotrophic Lateral Sclerosis (ALS). NDs are characterized by a puzzling interplay of molecular and cellular defects affecting subset of neuronal populations in specific affected brain areas.

OBJECTIVE

In present study, comparative in silico analysis was performed by utilizing gene expression datasets of AD, PD, FTD and ALS to identify potential common features to gain insights into complex molecular pathophysiology of the selected NDs.

METHODS

Gene expression data of four disorders were subjected to the identification of Differential Gene Expression (DEG) and their mapping on biological processes, KEGG pathways and molecular functions. Detailed comparative analysis was performed to highlight the common grounds of these dis-orders at various stages.

RESULTS

Astoundingly, 106 DEGs were found to be common across all disorders. Alongwith in total 100 GO terms and 7 KEGG pathways were found to be significantly enriched across all disorders. EGFR, CDC42 and CREBBP have been identified as the significantly interacting nodes in gene-gene in-teraction and in Protein-Protein Interaction (PPI) network as well. Furthermore, interaction of common DEGs targets with miRNA's has been scrutinized.

CONCLUSION

The complex molecular underpinnings of these disorders are currently elusive. Despite heterogeneous clinical and pathological expressions, common features have been recognized in many NDs which provide evidence of their convergence.

Therapeutic time window for the effects of erythropoietin on astrogliosis and neurite outgrowth in an in vitro model of spinal cord injury

BACKGROUND

The objective of this study was to investigate the underlying molecular mechanisms and the therapeutic time window for preventing astrogliosis with erythropoietin (EPO) treatment after in vitro modeled spinal cord injury (SCI).

METHODS

Cultured rat spinal cord astrocytes were treated with kainate and scratching to generate an in vitro model of SCI. EPO (100U/mL or 300U/mL) was added immediately or 2, 4, or 8 hours after injury. Some cultures were also treated with AG490, an inhibitor of the EPO-EPO receptor (EpoR) pathway mediator Janus kinase 2 (JAK2). To evaluate neurite extension, rat embryonic spinal cord neurons were seeded onto astrocyte cultures and treated with EPO immediately after injury in the presence or absence of anti-EpoR antibody.

RESULTS

EPO treatment at up to 8 hours after injury reduced the expression of axonal growth inhibiting molecules (glial fibrillary acidic protein, vimentin, and chondroitin sulfate proteoglycan), cytoskeletal regulatory proteins (Rho-associated protein kinase and ephephrin A4), and proinflammatory cytokines (tumor necrosis factor-alpha, transforming growth factor-beta, and phosphorylated-Smad3) in a dosedependent manner (P < .001). Most effects peaked with EPO treatment 2-4hours after injury. Additionally, EPO treatment up to 4 hours after injury promoted expression of the EpoR (>2-fold) and JAK2 (>3-fold) in a dose-dependent manner (P < .001), whereas co-treatment with AG490 precluded these effects (P < .001). EPO treatment up to 4hours after injury also enhanced axonal b-III tubulin-immunoreactivity (>12-fold), and this effect was precluded by co-treatment with an anti-EpoR antibody (P < .001).

CONCLUSIONS

EPO treatment within 8 hours after injury reduced astrogliosis, and EPO treatment within 4 hours promoted neurite outgrowth. EPO therapy immediately after spinal cord injury may regulate glia to generate an environment permissive of axonal regeneration.

Neuronal prolyl-4-hydroxylase 2 deficiency improves cognitive abilities in a murine model of cerebral hypoperfusion

Episodes of cerebral hypoxia/ischemia increase the risk of dementia, which is associated with impaired learning and memory. Previous studies in rodent models of dementia indicated a favorable effect of the hypoxia-inducible factor (HIF) targets VEGF (vascular endothelial growth factor) and erythropoietin (Epo). In the present study we thus investigated whether activation of the entire adaptive HIF pathway in neurons by cell-specific deletion of the HIF suppressor prolyl-4-hydroxylase 2 (PHD2) improves cognitive abilities in young (3months) and old (18-28months) mice suffering from chronic brain hypoperfusion. Mice underwent permanent occlusion of the left common carotid artery, and cognitive function was assessed using the Morris water navigation task. Under conditions of both normal and decreased brain perfusion, neuronal PHD2 deficiency resulted in improved and faster spatial learning in young mice, which was preserved to some extent also in old animals. The loss of PHD2 in neurons resulted in enhanced hippocampal mRNA and protein levels of Epo and VEGF, but did not alter local microvascular density, dendritic spine morphology, or expression of synaptic plasticity-related genes in the hippocampus. Instead, better cognitive function in PHD2 deficient animals was accompanied by an increased number of neuronal precursor cells along the subgranular zone of the dentate gyrus. Overall, our current pre-clinical findings indicate an important role for the endogenous oxygen sensing machinery, encompassing PHDs, HIFs and HIF target genes, for proper cognitive function. Thus, pharmacological compounds affecting the PHD-HIF axis might well be suited to treat cognitive dysfunction and neurodegenerative processes.

Neuroprotection and CD131/GDNF/AKT Pathway of Carbamylated Erythropoietin in Hypoxic Neurons

Carbamylated erythropoietin (CEPO), an EPO derivative, is attracting widespread interest due to neuroprotective effects without erythropoiesis. However, little is known about molecular mechanisms behind CEPO-mediated neuroprotection. In primary neurons with oxygen-glucose deprivation (OGD) and mice with hypoxia-reoxygenation, the neuroprotection and possible molecular mechanism of CEPO were performed by immunohistochemistry and immunocytochemistry, Western blot, RT-PCR, and ELISA. The comparisons were analyzed by ANOVA followed by unpaired two-tailed Student's t test. Both CEPO and EPO showed the neuroprotective effects in OGD model and hypoxic brain. CEPO did not trigger JAK-2 but activated AKT through glial cell line-derived neurotrophic factor (GDNF). It has been shown that CEPO acts upon a heteroreceptor complex comprising both the EPO receptor and the common β receptor subunit (βcR, also known as CD131). The blockage of CD131 reduced CEPO-mediated GDNF production, while GFR receptor blockage and GDNF neutralization inhibited CEPO-induced neurogenesis. Addition of GDNF to cultured neurons increased phosphorylation of AKT. CEPO protects neurons possible through the CD131/GDNF/AKT pathway.

Carbamylated erythropoietin enhances mice ventilatory responses to changes in O2 but not CO2 levels

Erythropoietin (EPO) has beneficial tissue-protective effects in several diseases but erythrocytosis may cause deleterious effects in EPO-treated patients. Thus carbamylated-EPO (C-EPO) and other derivatives retaining tissue-protective but lacking bone marrow-stimulating actions have been developed. Although EPO modulates ventilatory responses, the effects of C-EPO on ventilation have not been investigated. Here, basal breathing and respiratory chemoreflexes were measured by plethysmography after acute and chronic treatments with recombinant human C-EPO (rhC-EPO; 15,000 IU/kg during 5days) or saline (control group). Hematocrit, plasma and brainstem rhC-EPO levels were also quantified. Chronic rhC-EPO significantly elevated tissue rhC-EPO levels but not hematocrit. None of the drug regimen altered basal ventilation (normoxia). Chronic but not acute rhC-EPO enhanced hyperoxic ventilatory depression, and sustained the hypoxic ventilatory response mainly via a reduction of the roll-off phase. By contrast, rhC-EPO did not blunt the ventilatory response to hypercapnia. Thus, chronic C-EPO may be a promising therapy to improve breathing during hypoxia while minimizing adverse effects on cardiovascular function.

Carbamylated Erythropoietin: A Prospective Drug Candidate for Neuroprotection

Carbamylated erythropoietin (cEpo), which is neuroprotective but lacks hematopoietic activity, has been attracting rising concerns. However, the cellular and molecular mechanisms involved in the process of neuroprotection of cEpo are not well known. Based on several recent reports, the neuroprotective effects of cEpo are illustrated, and signaling pathways involved in the different effects of erythropoietin and cEpo are discussed. These newly reported researches may shed new light on the development and application of cEpo, a prospective drug candidate for neuroprotection.

Erythropoietin and carbamylated erythropoietin promote histone deacetylase 5 phosphorylation and nuclear export in rat hippocampal neurons

Erythropoietin (EPO) produces neurotrophic effects in animal model of neurodegeneration. However, clinical use of EPO is limited due to thrombotic risk. Carbamylated EPO (cEPO), devoid of thrombotic risk, has been proposed as a novel neuroprotective and neurotrophic agent although the molecular mechanisms of cEPO remain incomplete. Here, we show a previously unidentified role of histone deacetylase 5 (HDAC5) in the actions of EPO and cEPO. EPO and cEPO regulate the HDAC5 phosphorylation at two critical sites, Ser259 and Ser498 through a protein kinase D (PKD) dependent pathway. In addition, EPO and cEPO rapidly stimulates nuclear export of HDAC5 in rat hippocampal neurons which expressing HDAC5-GFP. Consequently, EPO and cEPO enhanced the myocyte enhancer factor-2 (MEF2) target gene expression. Taken together, our results reveal that EPO and cEPO mediate MEF2 target gene expression via the regulation of HDAC5 phosphorylation at Ser259/498, and suggest that HDAC5 could be a potential mechanism contributing to the therapeutic actions of EPO and cEPO.

β Common Receptor Mediates Erythropoietin-Conferred Protection on OxLDL-Induced Lipid Accumulation and Inflammation in Macrophages

Erythropoietin (EPO), the key factor for erythropoiesis, also protects macrophage foam cells from lipid accumulation, yet the definitive mechanisms are not fully understood. β common receptor (βCR) plays a crucial role in the nonhematopoietic effects of EPO. In the current study, we investigated the role of βCR in EPO-mediated protection in macrophages against oxidized low-density lipoprotein- (oxLDL-) induced deregulation of lipid metabolism and inflammation. Here, we show that βCR expression was mainly in foamy macrophages of atherosclerotic aortas from apolipoprotein E-deficient mice. Results of confocal microscopy and immunoprecipitation analyses revealed that βCR was colocalized and interacted with EPO receptor (EPOR) in macrophages. Inhibition of βCR activation by neutralizing antibody or small interfering RNA (siRNA) abolished the EPO-conferred protection in oxLDL-induced lipid accumulation. Furthermore, EPO-promoted cholesterol efflux and upregulation of ATP-binding cassette (ABC) transporters ABCA1 and ABCG1 were prevented by pretreatment with βCR neutralizing antibody or βCR siRNA. Additionally, blockage of βCR abrogated the EPO-conferred anti-inflammatory action on oxLDL-induced production of macrophage inflammatory protein-2. Collectively, our findings suggest that βCR may play an important role in the beneficial effects of EPO against oxLDL-elicited dysfunction of macrophage foam cells.

The lack of CD131 and the inhibition of Neuro-2a growth by carbamylated erythropoietin

Recombinant human erythropoietin (EPO), a glycohormone, is one of the leading biopharmaceutical products, while carbamylated erythropoietin (CEPO), an EPO derivative, is attracting widespread interest due to its neuroprotective effects without erythropoiesis in several cells and animal models. However, exogenous EPO promotes an angiogenic response from tumor cells and is associated with tumor growth, but knowledge of CEPO on tumor growth is lacking. Here we show that CEPO, but not EPO, inhibited Neuro-2a growth and viability. As expected, CEPO--unlike EPO--did not activate JAK-2 either in primary neurons or in Neuro-2a cells. Interestingly, CEPO did not induce GDNF expression and subsequent AKT activation in Neuro-2a cells. Before CEPO/EPO treatment, glial cell line-derived neurotrophic factor (GDNF) neutralization and GFR receptor blocking decreased the viability of EPO-treated Neuro-2a cells but did not influence CEPO-treated Neuro-2a cells. As compared to primary neurons, the expression of CD131, as a receptor complex binding to CEPO, is almost lacking in Neuro-2a cells. In BABL/C-nu mice, CEPO did not promote the growth of Neuro-2a cells nor extended the survival time compared to mice treated with EPO. The results indicate that CEPO did not promote tumor growth because of lower expression of CD131 and subsequent dysfunction of CD131/GDNF/AKT pathway in Neuro-2a cells, revealing its therapeutic potential in future clinical application.

Further improving the cognitive effect profile of electroconvulsive therapy (ECT): the case for studying carbamylated erythropoietin

Electroconvulsive therapy (ECT) remains the most effective acute treatment for severe depression and several other psychiatric illnesses. However, its use has been limited by concerns about cognitive adverse effects. ECT may cause temporary cognitive impairment in some patients, typically anterograde amnesia for 1-2 weeks after a course of treatment, and circumscribed retrograde amnesia. These cognitive effects largely disappear within days to weeks after treatment. Efforts to find a pharmacological agent to reduce the cognitive effects of ECT have largely been unsuccessful, with the possible exception of thyroid hormone. We review the literature on pharmacological attempts to attenuate ECT's cognitive effects, and propose a novel neuroprotective and neurotrophic agent, carbamylated erythropoietin (CEPO), for this indication.