The cytokine erythropoietin (Epo) is tissue-protective in preclinical models of ischemic, traumatic, toxic, and inflammatory injuries. We have recently characterized Epo derivatives that do not bind to the Epo receptor (EpoR) yet are tissue-protective. For example, carbamylated Epo (CEpo) does not stimulate erythropoiesis, yet it prevents tissue injury in a wide variety of in vivo and in vitro models. These observations suggest that another receptor is responsible for the tissue-protective actions of Epo. Notably, prior investigation suggests that EpoR physically interacts with the common ␤ receptor (␤cR), the signal-transducing subunit shared by the granulocyte-macrophage colony stimulating factor, and the IL-3 and IL-5 receptors. However, because ␤cR knockout mice exhibit normal erythrocyte maturation, ␤cR is not required for erythropoiesis. We hypothesized that ␤cR in combination with the EpoR expressed by nonhematopoietic cells constitutes a tissueprotective receptor. In support of this hypothesis, membrane proteins prepared from rat brain, heart, liver, or kidney were greatly enriched in EpoR after passage over either Epo or CEpo columns but covalently bound in a complex with ␤cR. Further, antibodies against EpoR coimmunoprecipitated ␤cR from membranes prepared from neuronal-like P-19 cells that respond to Epo-induced tissue protection. Immunocytochemical studies of spinal cord neurons and cardiomyocytes protected by Epo demonstrated cellular colocalization of Epo ␤cR and EpoR. Finally, as predicted by the hypothesis, neither Epo nor CEpo was active in cardiomyocyte or spinal cord injury models performed in the ␤cR knockout mouse. These data support the concept that EpoR and ␤cR comprise a tissue-protective heteroreceptor.

Erythropoietin (EPO), a member of the type 1 cytokine superfamily, plays a critical hormonal role regulating erythrocyte production as well as a paracrine/autocrine role in which locally produced EPO protects a wide variety of tissues from diverse injuries. Significantly, these functions are mediated by distinct receptors: hematopoiesis via the EPO receptor homodimer and tissue protection via a heterocomplex composed of the EPO receptor and CD131, the ␤ common receptor. In the present work, we have delimited tissueprotective domains within EPO to short peptide sequences. We demonstrate that helix B (amino acid residues 58 -82) of EPO, which faces the aqueous medium when EPO is bound to the receptor homodimer, is both neuroprotective in vitro and tissue protective in vivo in a variety of models, including ischemic stroke, diabetes-induced retinal edema, and peripheral nerve trauma. Remarkably, an 11-aa peptide composed of adjacent amino acids forming the aqueous face of helix B is also tissue protective, as confirmed by its therapeutic benefit in models of ischemic stroke and renal ischemia-reperfusion. Further, this peptide simulating the aqueous surface of helix B also exhibits EPO's trophic effects by accelerating wound healing and augmenting cognitive function in rodents. As anticipated, neither helix B nor the 11-aa peptide is erythropoietic in vitro or in vivo. Thus, the tissue-protective activities of EPO are mimicked by small, nonerythropoietic peptides that simulate a portion of EPO's three-dimensional structure.cognition ͉ cytoprotection ͉ excitotoxicity ͉ ischemia-reperfusion injury ͉ wound healing

BackgroundEpidemiologic data on malaria are scant in many high-burden countries including the Democratic Republic of the Congo (DRC), which suffers the second-highest global burden of malaria. Malaria control efforts in regions with challenging infrastructure require reproducible and efficient surveillance. We employed new high-throughput molecular testing to characterize the state of malaria control in the DRC and estimate childhood mortality attributable to excess malaria transmission.Methods and FindingsThe Demographic and Health Survey was a cross-sectional, population-based cluster household survey of adults aged 15–59 years in 2007 employing structured questionnaires and dried blood spot collection. Parasitemia was detected by real-time PCR, and survey responses measured adoption of malaria control measures and under-5 health indices. The response rate was 99% at the household level, and 8,886 households were surveyed in 300 clusters; from 8,838 respondents molecular results were available. The overall prevalence of parasitemia was 33.5% (95% confidence interval [C.I.] 32–34.9); P. falciparum was the most prevalent species, either as monoinfection (90.4%; 95% C.I. 88.8–92.1) or combined with P. malariae (4.9%; 95% C.I. 3.7–5.9) or P. ovale (0.6%; 95% C.I. 0.1–0.9). Only 7.7% (95% CI 6.8–8.6) of households with children under 5 owned an insecticide-treated bednet (ITN), and only 6.8% (95% CI 6.1–7.5) of under-fives slept under an ITN the preceding night. The overall under-5 mortality rate was 147 deaths per 1,000 live births (95% C.I. 141–153) and between clusters was associated with increased P. falciparum prevalence; based on the population attributable fraction, 26,488 yearly under-5 deaths were attributable to excess malaria transmission.ConclusionsAdult P. falciparum prevalence is substantial in the DRC and is associated with under-5 mortality. Molecular testing offers a new, generalizable, and efficient approach to characterizing malaria endemicity in underserved countries.

The essential biological role of erythropoietin (EPO) in maintaining erythrocyte mass has been well understood for many years. Although EPO is required for the maturation of red cells, it also has strong procoagulant effects on the vascular endothelium and platelets, which limit erythrocyte losses after hemorrhage. Like other members of the type 1 cytokine superfamily, EPO has multiple biological activities. For the past 10 years, multiple investigators have shown that EPO acts as a locally produced antagonist of proinflammatory cytokines that are generated by the innate immune response in response to infection, trauma, or metabolic stress. Specifically, EPO inhibits apoptosis of cells surrounding a locus of injury, reduces the influx of inflammatory cells, and recruits tissue-specific stem cells and endothelial progenitor cells. Available evidence suggests that these multiple, nonerythropoietic effects of EPO are mediated by a tissue protective receptor (TPR) that is distinct from the homodimeric receptor responsible for erythropoiesis. Notably, activation of the TPR requires a higher concentration of EPO than is needed for maximal erythropoiesis. Unfortunately, these higher concentrations of EPO also stimulate hematopoietic and pro-coagulant pathways, which can cause adverse effects and, therefore, potentially limit the clinical use of EPO for tissue protection. To circumvent these problems, the EPO molecule has been successfully modified in a variety of ways to interact only with the TPR. Early clinical experience has shown that these compounds appear to be safe, and proof of concept trials are ready to begin.

We have shown recently that cDNA vaccination, using a virtual lymph node, ameliorates experimental allergic encephalomyelitis. Successful cure from mammary tumor requires resolution of local tumor growth and metastases. We have examined whether targeting of CD44 cell surface adhesion molecule by cDNA vaccination plays a role in resolving mammary tumor development. We show here that CD44 cDNA vaccination decreases the tumor mass and metastatic potential in experimental mammary tumor of BALB/c mice. Vaccination of mice, inoculated with the mammary tumors, by cDNA of CD44 variant (CD44v) but not by cDNA of standard CD44, markedly reduced local tumor development and lung metastasis. Concomitantly, transfection of CD44 antisense into a highly metastatic mammary tumor cell line disrupted the CD44 expression of the cells and reduced their ability to establish local tumors as well as metastatic colonies in the lung. Moreover, when CD44v, but not standard CD44 sense cDNA, was transfected into the poorly metastatic cell line, tumor development was markedly enhanced. It is possible therefore that DNA vaccination with a specific CD44v construct could induce an immune resistance to mammary tumor progression. [Mol Cancer Ther 2008; 7(6):1615 -23]