Conditioning for hematopoietic transplantation activates the complement cascade and induces a proteolytic environment in bone marrow: A novel role for bioactive lipids and soluble C5b-C9 as homing factors

Department of Medicine, Stem Cell Institute at the James Graham Brown Cancer Center, University of Louisville, Louisville, KY 40202, USA.
Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, U.K (Impact Factor: 10.43). 07/2011; 26(1):106-16. DOI: 10.1038/leu.2011.185
Source: PubMed


We have observed that conditioning for hematopoietic transplantation by lethal irradiation induces a proteolytic microenvironment in the bone marrow (BM) that activates the complement cascade (CC). As a result, BM is enriched for proteolytic enzymes and the soluble form of the terminal product of CC activation, the membrane attack complex C5b-C9 (MAC). At the same time, proteolytic enzymes induced in irradiated BM impair the chemotactic activity of α-chemokine stromal-derived factor-1 (SDF-1). As SDF-1 is considered a crucial BM chemoattractant for transplanted hematopoietic stem/progenitor cells (HSPCs), we sought to determine whether other factors that are resistant to proteolytic enzymes have a role in this process, focusing on proteolysis-resistant bioactive lipids. We found that the concentrations of sphingosine-1-phosphate (S1P) and ceramide-1-phosphate (C1P) increase in the BM after conditioning for transplantation and that both S1P and, as we show here for the first time, C1P are potent chemoattractants for HSPCs. Next, we observed that C5-deficient mice that do not generate MAC show impaired engraftment of HSPCs. In support of a role for MAC in homing and engraftment, we found that soluble MAC enhances in a CR3 (CD11b/CD18)-dependent manner the adhesion of HSPCs to BM stromal cells and increases the secretion of SDF-1 by BM stroma. We conclude that an increase in BM levels of proteolytic enzyme-resistant S1P and C1P and activation of CC, which leads to the generation of MAC, has an important and previously underappreciated role in the homing of transplanted HSPCs.

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Available from: Chihwa Kim, Jul 16, 2014
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    • "The promotion of cell migration by extracellular C1P has been recently confirmed in other cell types. For instance, Kim and co-workers found that extracellular C1P potently stimulated migration of hematopoietic stem progenitor cells [33], multipotent stromal cells, and endothelial progenitor cells [14]. In addition, Karapetyan and co-workers reported that extracellular C1P stimulated migration of bone marrow derived stem cells in patients suffering from acute myocardial infarction [34]. "
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    ABSTRACT: Ceramide 1-phosphate (C1P) was recently demonstrated to potently induce cell migration. This action could only be observed when C1P was applied exogenously to cells in culture, and was inhibited by pertussis toxin. However, the mechanisms involved in this process are poorly understood. In this work, we found that phosphatidic acid (PA), which is structurally related to C1P, displaced radiolabeled C1P from its membrane-binding site and inhibited C1P-stimulated macrophage migration. This effect was independent of the saturated fatty acid chain length or the presence of a double bond in each of the fatty acyl chains of PA. Treatment of RAW264.7 macrophages with exogenous phospholipase D (PLD), an enzyme that produces PA from membrane phospholipids, also inhibited C1P-stimulated cell migration. Likewise, PA or exogenous PLD inhibited C1P-stimulated extracellularly regulated kinases (ERK) 1 and 2 phosphorylation, leading to inhibition of cell migration. However, PA did not inhibit C1P-stimulated Akt phosphorylation. It is concluded that PA is a physiological regulator of C1P-stimulated macrophage migration. These actions of PA may have important implications in the control of pathophysiological functions that are regulated by C1P, including inflammation and various cellular processes associated with cell migration such as organogenesis or tumor metastasis.
    Biochemical Pharmacology 10/2014; 92(4). DOI:10.1016/j.bcp.2014.10.005 · 5.01 Impact Factor
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    • "Also, SDF-1 upregulation was observed in tissues injured by hypoxia, and similar upregulation takes place in the BM microenvironment during conditioning for transplantation by radiochemotherapy or after administration of pharmacological agents that promote mobilization of BMSPCs (such as G-CSF or a CXCR4 antagonist AMD3100) [18, 26–28]. Ironically, these conditions induce upregulation of several proteolytic enzymes released by BM cells, such as metalloproteinase 2 (MMP-2), MMP-9, cathepsin G, and neutrophil elastase, thereby proteolytically inactivating SDF-1 and CXCR4 and neutralizing chemotactic activity of SDF-1 towards BMSPCs [26, 29, 30]. It is important to note that this proteolytic environment would promote HSPC mobilization by decreasing SDF-1-CXCR4-mediated retention (as well as attenuating VLA-4-CD106 interaction); however SDF-1 homing would be impaired due to enhanced proteolytic degradation of SDF-1 [18, 26, 31]. "
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    ABSTRACT: Despite significant advances in medical therapy and interventional strategies, the prognosis of millions of patients with acute myocardial infarction (AMI) and ischemic heart disease (IHD) remains poor. Currently, short of heart transplantation with all of its inherit limitations, there are no available treatment strategies that replace the infarcted myocardium. It is now well established that cardiomyocytes undergo continuous renewal, with contribution from bone marrow (BM)-derived stem/progenitor cells (SPCs). This phenomenon is upregulated during AMI by initiating multiple innate reparatory mechanisms through which BMSPCs are mobilized towards the ischemic myocardium and contribute to myocardial regeneration. While a role for the SDF-1/CXCR4 axis in retention of BMSPCs in bone marrow is undisputed, its exclusive role in their mobilization and homing to a highly proteolytic microenvironment, such as the ischemic/infarcted myocardium, is currently being challenged. Recent evidence suggests a pivotal role for bioactive lipids in the mobilization of BMSPCs at the early stages following AMI and their homing towards ischemic myocardium. This review highlights the recent advances in our understanding of the mechanisms of stem cell mobilization, provides newer evidence implicating bioactive lipids in BMSPC mobilization and differentiation, and discusses their potential as therapeutic agents in the treatment of IHD.
    01/2014; 2014:653543. DOI:10.1155/2014/653543
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    • "Plasma SDF-1 levels were evaluated by employing a sandwich enzyme-linked immunosorbent assay (ELISA) using a commercially available ELISA system (R & D Systems, Minneapolis, MN, USA) as described [4, 8]. "
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    ABSTRACT: Sphingosine-1-phosphate (S1P) is a crucial chemotactic factor in peripheral blood (PB) involved in the mobilization process and egress of hematopoietic stem/progenitor cells (HSPCs) from bone marrow (BM). Since S1P is present at high levels in erythrocytes, one might assume that, by increasing the plasma S1P level, the hemolysis of red blood cells would induce mobilization of HSPCs. To test this assumption, we induced hemolysis in mice by employing phenylhydrazine (PHZ). We observed that doubling the S1P level in PB from damaged erythrocytes induced only a marginally increased level of mobilization. However, if mice were exposed to PHZ together with the CXCR4 blocking agent, AMD3100, a robust synergistic increase in the number of mobilized HSPCs occurred. We conclude that hemolysis, even if it significantly elevates the S1P level in PB, also requires attenuation of the CXCR4-SDF-1 axis-mediated retention in BM niches for HSPC mobilization to occur. Our data also further confirm that S1P is a major chemottractant present in plasma and chemoattracts HSPCs into PB under steady-state conditions. However, to egress from BM, HSPCs first have to be released from BM niches by blocking the SDF-1-CXCR4 retention signal.
    12/2013; 2013(12):814549. DOI:10.1155/2013/814549
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