Carbon Monoxide Induced Erythroid Differentiation of K562 Cells Mimics the Central Macrophage Milieu in Erythroblastic Islands

Abstract

Growing evidence supports the role of erythroblastic islands (EI) as microenvironmental niches within bone marrow (BM), where cell-cell attachments are suggested as crucial for erythroid maturation. The inducible form of the enzyme heme oxygenase, HO-1, which conducts heme degradation, is absent in erythroblasts where hemoglobin (Hb) is synthesized. Yet, the central macrophage, which retains high HO-1 activity, might be suitable to take over degradation of extra, harmful, Hb heme. Of these enzymatic products, only the hydrophobic gas molecule - CO can transfer from the macrophage to surrounding erythroblasts directly via their tightly attached membranes in the terminal differentiation stage. Based on the above, the study hypothesized CO to have a role in erythroid maturation. Thus, the effect of CO gas as a potential erythroid differentiation inducer on the common model for erythroid progenitors, K562 cells, was explored. Cells were kept under oxygen lacking environment to mimic BM conditions. Nitrogen anaerobic atmosphere (N 2 A) served as control for CO atmosphere (COA). Under both atmospheres cells proliferation ceased: in N 2 A due to cell death, while in COA as a result of erythroid differentiation. Maturation was evaluated by increased glycophorin A expression and Hb concentration. Addition of 1%CO only to N 2 A, was adequate for maintaining cell viability. Yet, the average Hb concentration was low as compared to COA. This was validated to be the outcome of diversified maturation stages of the progenitor's population. In fact, the above scenario mimics the in vivo EI conditions, where at any given moment only a minute portion of the progenitors proceeds into terminal differentiation. Hence, this model might provide a basis for further molecular investigations of the EI structure/function relationship.

Enhancements of the production of bilirubin and the expression of β‐globin by carbon monoxide during erythroid differentiation

“…As CO has profound effects on mitochondrial and cellular respiration and other hemoproteins , it may have positive effects on erythroid differentiation. A previous study reported that HO‐1 and CO induced the erythroid differentiation of K562 cells under anoxic conditions. Garcia‐Santos et al .…”

Role of Heme Oxygenase-1 in Postnatal Differentiation of Stem Cells: A Possible Cross-Talk with MicroRNAs

“…Interestingly, the lack of HO-1 expression in erythroblasts is well described in both K562 erythroid cell line (7) and primary human bone marrow-derived erythroid progenitors (7). Oppositely, HO-1 is constitutively expressed in macrophages; therefore, it has been suggested that HO-1 activity in these cells is crucial to regulate erythropoiesis (211). Indeed, exogenous CO accelerated the differentiation of K562 cells in vitro (211).…”

“…Oppositely, HO-1 is constitutively expressed in macrophages; therefore, it has been suggested that HO-1 activity in these cells is crucial to regulate erythropoiesis (211). Indeed, exogenous CO accelerated the differentiation of K562 cells in vitro (211). Moreover, in the in vivo model of HO-1 + / -bone marrow transplantation, the differentiation of erythroblasts was impaired (30).…”

Application of immortalized human erythroid progenitor cell line in serologic tests to detect red blood cell alloantibodies

“…9,10 However, the amount of Hb subsequently produced is greatly inferior to that produced by RBCs. 11 In contrast, immortalized human-induced pluripotent stem cellderived erythroid progenitor (HiDEP) cell lines can constitutively synthesize Hb, and these cells are deep red in color, even before differentiation. 12 Therefore, HiDEP cell lines are expected to be a novel source of cells for the generation of reagent RBCs for screening for unexpected antibodies because of their unique characteristics.…”