title: The therapeutic potential of erythropoiesis-stimulating agents for tissue protection: a tale of two receptors.
abstract: Erythropoietin (EPO) is a well-known therapeutic protein employed widely in the treatment of anemia. Over the past decade, abundant evidence has shown that in addition to its systemic role in the regulation of plasma pO(2) by modulating erythrocyte numbers, EPO is also a cytoprotective molecule made locally in response to injury or metabolic stress. Many studies have shown beneficial effects of EPO administration in reducing damage caused by ischemia-reperfusion, trauma, cytotoxicity, infection and inflammation in a variety of organs and tissues. Notably, the receptor mediating the nonerythropoietic effects of EPO differs from the one responsible for hematopoiesis. The tissue-protective receptor exhibits a lower affinity for EPO and is a heteromer consisting of EPO receptor monomers in association with the common receptor that is also employed by granulocyte macrophage colony-stimulating factor, interleukin 3, and interleukin 5. This heteromeric receptor is expressed immediately following injury, whereas EPO production is delayed. Thus, early administration of EPO can dramatically reduce the deleterious components of the local inflammatory cascade. However, a high dose of EPO is required and this also stimulates the bone marrow to produce highly reactive platelets and activates the vascular endothelium into a prothrombotic state. To circumvent these undesirable effects, the EPO molecule has been successfully altered to selectively eliminate erythropoietic and prothrombotic potencies, while preserving tissue-protective activities. Very recently, small peptide mimetics have been developed that recapitulate the tissue-protective activities of EPO. Nonerythropoietic tissue-protective molecules hold high promise in a wide variety of acute and chronic diseases.
authors.affiliation: Warren Pharmaceuticals, Ossining, N.Y., USA. mbrines@warrenpharma.com
authors.forename: Michael
authors.initials: M
authors.lastname: Brines
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D053648:Cytokine Receptor Common beta Subunit / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D016207:Cytokines / Q000378:metabolism; D015195:Drug Design; D004921:Erythropoietin / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry / Q000493:pharmacokinetics / Q000502:physiology / Q000627:therapeutic use; D025461:Feedback, Physiological; D006397:Hematinics / Q000008:administration & dosage / Q000009:adverse effects / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D006410:Hematopoiesis / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000517:prevention & control; D018836:Inflammation Mediators / Q000378:metabolism; D053614:Janus Kinase 2 / Q000502:physiology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D055503:Protein Multimerization; D017467:Receptors, Erythropoietin / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*; D011994:Recombinant Proteins; D015427:Reperfusion Injury / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D050791:STAT Transcription Factors / Q000502:physiology; D013312:Stress, Physiological / Q000187:drug effects*; D014947:Wounds and Injuries / Q000188:drug therapy* / Q000276:immunology / Q000503:physiopathology
chemical_list: D053648:Cytokine Receptor Common beta Subunit; D016207:Cytokines; D006397:Hematinics; D018836:Inflammation Mediators; D017467:Receptors, Erythropoietin; D011994:Recombinant Proteins; D050791:STAT Transcription Factors; D004921:Erythropoietin; D053614:Janus Kinase 2