Bergamaschi G, Recalde H H, Ponchio L, Rosti V, Cazzola M
Department of Internal Medicine and Medical Therapy, University of Pavia, Italy.
Exp Hematol. 1993 Jan;21(1):70-3.
The aim of the present study was to evaluate whether the erythropoietic response to hemolysis can be mediated by other regulatory peptides in addition to erythropoietin. For this purpose, we have investigated the influence of erythrophagocytosis by human monocytes and macrophages on the mRNA expression of several growth factor genes, including interleukin-3 (IL-3), granulocyte/macrophage colony-stimulating factor (GM-CSF) and erythroid potentiating activity (EPA), which are supposed to influence erythropoiesis. Immunologically mediated erythrophagocytosis increased the expression of EPA mRNA (2 to 3 times). Such increase appeared to be specifically associated with phagocytosis of erythrocytes, since phagocytosis of yeast microorganisms or antibody-coated latex particles had no effect on EPA gene expression. Yeast, however, powerfully stimulated the expression of GM-CSF, granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6) mRNAs which, with the exception of G-CSF, were not influenced by erythrophagocytosis. Erythropoietin and IL-3 mRNAs were never detected in cultured monocytes, either in control or in treated samples. Our findings may suggest that phagocytosis of erythrocytes by monocytes/macrophages increases the expression, and possibly the production, of EPA. This could in turn potentiate the erythropoietic response to extravascular hemolysis by increasing the number of cells responsive to erythropoietin. Thus, EPA might be a mediator of an end-product positive feedback on the rate of red cell production.
本研究的目的是评估除促红细胞生成素外，溶血的促红细胞生成反应是否可由其他调节肽介导。为此，我们研究了人单核细胞和巨噬细胞的红细胞吞噬作用对几种生长因子基因mRNA表达的影响，这些生长因子包括白细胞介素-3（IL-3）、粒细胞/巨噬细胞集落刺激因子（GM-CSF）和红细胞生成增强活性（EPA），它们被认为会影响红细胞生成。免疫介导的红细胞吞噬作用使EPA mRNA的表达增加（2至3倍）。这种增加似乎与红细胞的吞噬作用特异性相关，因为酵母微生物或抗体包被的乳胶颗粒的吞噬作用对EPA基因表达没有影响。然而，酵母强烈刺激GM-CSF、粒细胞集落刺激因子（G-CSF）和白细胞介素-6（IL-6）mRNA的表达，除G-CSF外，这些因子不受红细胞吞噬作用的影响。在培养的单核细胞中，无论是对照样本还是处理样本，均未检测到促红细胞生成素和IL-3 mRNA。我们的研究结果可能表明，单核细胞/巨噬细胞对红细胞的吞噬作用会增加EPA的表达，并可能增加其产生。这反过来可能通过增加对促红细胞生成素反应的细胞数量来增强对血管外溶血的促红细胞生成反应。因此，EPA可能是对红细胞生成速率的终产物正反馈的一种介质。
