Bone Marrow Multipotent Mesenchymal Stromal Cells in Patients with Diffuse Large B-Cell Lymphoma

Molecular Changes in Immunological Characteristics of Bone Marrow Multipotent Mesenchymal Stromal Cells in Lymphoid Neoplasia

Immune system and bone marrow stromal cells play an important role in maintaining normal hematopoiesis. Lymphoid neoplasia disturbs not only development of immune cells, but other immune response mechanisms as well. Multipotent mesenchymal stromal cells (MSCs) of the bone marrow are involved in immune response regulation through both intercellular interactions and secretion of various cytokines. In hematological malignancies, the bone marrow stromal microenvironment, including MSCs, is altered. Aim of this study was to describe the differences of MSCs' immunological function in the patients with acute lymphoblastic leukemia (ALL) and diffuse large B-cell lymphoma (DLBCL). In ALL, malignant cells arise from the early precursor cells localized in bone marrow, while in DLBCL they arise from more differentiated B-cells. In this study, only the DLBCL patients without bone marrow involvement were included. Growth parameters, surface marker expression, genes of interest expression, and secretion pattern of bone marrow MSCs from the patients with ALL and DLBCL at the onset of the disease and in remission were studied. MSCs from the healthy donors of corresponding ages were used as controls. It has been shown that concentration of MSCs in the bone marrow of the patients with ALL is reduced at the onset of the disease and is restored upon reaching remission; in the patients with DLBCL this parameter does not change. Proliferative capacity of MSCs did not change in the patients with ALL; however, the cells of the DLBCL patients both at the onset and in remission proliferated significantly faster than those from the donors. Expression of the membrane surface markers and expression of the genes important for differentiation, immunological status maintenance, and cytokine secretion differed significantly in the MSCs of the patients from those of the healthy donors and depended on nosology of the disease. Secretomes of the MSCs varied greatly; a number of proteins associated with immune response regulation, differentiation, and maintenance of hematopoietic stem cells were depleted in the secretomes of the cells from the patients. Lymphoid neoplasia leads to dramatic changes in the functional immunological status of MSCs.

Biogenesis of Mitochondria in Multipotent Mesenchymal Stromal Cells in Patients with Acute Leukemia

In patients with acute leukemia, not only normal hematopoiesis, but also bone marrow stromal microenvironment is damaged. Multipotent mesenchymal stromal cells (MSC) are essential for the formation and function of the stromal microenvironment. Analysis of changes in MSC is important for the development of new approaches to leukemia therapy. The metabolism of mitochondria in MSC, relative content of mitochondrial DNA, and expression levels of genes encoding PGC-1α and Nrf2 proteins, important regulators of biogenesis, were studied using real-time PCR. Relative content of mitochondrial DNA does not change in MSC of acute leukemia patients at the onset of disease or in remission. Relative expression level of the gene encoding PGC-1α protein in MSC does not change significantly. However, relative expression level of the gene encoding Nrf2, an important antioxidant activity regulator, insignificantly decreases in patients at the onset of acute leukemia, and this decrease becomes significant upon reaching remission.

Acute Myeloid Leukemia Causes Serious and Partially Irreversible Changes in Secretomes of Bone Marrow Multipotent Mesenchymal Stromal Cells

In patients with acute myeloid leukemia (AML), malignant cells modify the properties of multipotent mesenchymal stromal cells (MSCs), reducing their ability to maintain normal hematopoiesis. The aim of this work was to elucidate the role of MSCs in supporting leukemia cells and the restoration of normal hematopoiesis by analyzing ex vivo MSC secretomes at the onset of AML and in remission. The study included MSCs obtained from the bone marrow of 13 AML patients and 21 healthy donors. The analysis of proteins contained in the MSCs-conditioned medium demonstrated that secretomes of patient MSCs differed little between the onset of AML and remission; pronounced differences were observed between MSC secretomes of AML patients and healthy donors. The onset of AML was accompanied by a decrease in the secretion of proteins related to ossification, transport, and immune response. In remission, but not at the onset, secretion of proteins responsible for cell adhesion, immune response, and complement was reduced compared to donors. We conclude that AML causes crucial and, to a large extent, irreversible changes in the secretome of bone marrow MSCs ex vivo. In remission, functions of MSCs remain impaired despite the absence of tumor cells and the formation of benign hematopoietic cells.

Dynamics of Changes in the Properties of Multipotent Mesenchymal Stromal Cells in Patients with Acute Leukemia

In acute leukemia, the stromal microenvironment of the bone marrow that regulates hematopoiesis is modified under the influence of malignant cells. Chemotherapy also adversely affects stromal cells. Multipotent mesenchymal stromal cells (MSC) are involved in the formation of the stromal microenvironment and in the regulation of normal and tumor hematopoietic cells. The properties of MSC from the bone marrow of patients with acute myeloid and lymphoid leukemia were studied at the onset of the disease and after achieving remission. The immunophenotype and the level of gene expression were analyzed in MSC of 34 patients. In MSC from patients with acute leukemia, the expression of CD105 and CD274 was significantly reduced in comparison with MSC from healthy donors. At the onset of the disease, the expression of IL6, JAG1, PPARG, IGF1, and PDGFRA was enhanced, while the expression of IL1B, IL8, SOX9, ANG1, and TGFB was reduced. All these changes affect the course of the disease in patients and can be the targets of therapeutic intervention.

Differences in Protein Secretion by Multipotent Mesenchymal Stromal Cells Effective and Ineffective in the Prevention of Acute Graft-Versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Multipotent mesenchymal stromal cells (MSC) were administered to patients after allogeneic hematopoietic stem cell transplantation to prevent the development of acute graft-versus- host disease (GVHD). The injection of MSC did not always prevent the development of GVHD. The aim of the work was to compare the secretome of MSC effective and ineffective in the prevention of GVHD. MSC were obtained from the bone marrow of hematopoietic stem cells donors. The secretome was studied using a TripleTOF 5600+ mass spectrometer with a NanoSpray III ion source coupled to a NanoLC Ultra 2D Plus nano-HPLC System. A total of 1,965 proteins were analyzed. Analysis of the secretome of effective and ineffective MSC samples revealed significant differences in the secretion of 1,119 proteins associated with ribosomes, exosomes, focal contacts, and others. Analysis of proteins secreted by MSC can be used to identify prognostically effective samples.

Changes in Bone Marrow Stromal Progenitor Cells in Patients with Hematoblastosis at the Onset of the Disease

Multipotent mesenchymal stromal cells (MSC) are the key regulators of hematopoiesis. We studied changes in MSC characteristics in patients with myeloid leukemia and patients with lymphoproliferative diseases. MSC were obtained from the bone marrow of patients at the time of diagnostic puncture using a standard technique. Their proliferative potential and expression of genes associated with differentiation and regulation of hematopoiesis were studied. The total cell production of MSC in patients with leukemia at the onset of the disease did not differ from that in the group of healthy donors. The relative expression of the IL6, TGFb1 and TGFb2, PPARG genes was similar in all patients. The relative expression of the JAG1, LIF, IGF1, CSF1, IL1b, and IL1bR1 genes in MSC of patients with leukemia was enhanced and the relative expression of SDF1 was unchanged in comparison with MSC from donors. MSC from patients with leukemia were characterized by enhanced relative expression of PDGFRA and PDGFRB, and reduced expression of SOX9. Changes functions of the stromal microenvironment in patients with hemoblastoses attested to the role of stromal cells in the maintenance and spread of tumor cells.

Role of the Bone Marrow Niche in Supporting the Pathogenesis of Lymphoid Malignancies

While the bone marrow (BM) microenvironment is the primary location for nurturing the multipotent hematopoietic stem cells and developing the blood cells of either myeloid or lymphoid origin under normal physiological conditions, it could provide a supportive milieu for the proliferation of blood cancer cells. In fact, the multiple and complex direct cell-to-cell or indirect soluble factors-mediated interactions taking place among the BM cells of different origins are shown to play a significant role in tumorigenesis of hematological cancers. In the current review, we focus on lymphoid malignancies and highlight the novel insights surrounding the role of both cellular as well as non-cellular BM compartments in modulating hematopoiesis and promoting growth and proliferation of cancer cells across a variety of aggressive and indolent lymphoid malignancies, including diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, and Waldenstrom Macroglobulinemia. We also discuss the mechanisms of potential intervention and discuss their therapeutic impact in clinical settings.

Humoral Effect of a B-Cell Tumor on the Bone Marrow Multipotent Mesenchymal Stromal Cells

The properties of bone marrow (BM)-derived multipotent mesenchymal stromal cells (MSCs) are altered in the patients with the diffuse large B cell lymphoma (DLBCL) without BM involvement. It was suggested that plasma from the patients contains soluble factors that affect MSCs. Plasma and BM-derived MSCs from the DLBCL patients at the onset of the disease and one month after the end of treatment were studied. Concentration of the plasma cytokines and gene expression in the MSCs were evaluated by the Bio-Plex Pro Human Cytokine Panel kit to measure 27 analytes and real-time PCR. Plasma and MSCs from the healthy donors were used as controls. Analysis of cytokines in the plasma from healthy donors and patients before and one month after the end of treatment revealed significant differences in the concentration of 14 out of 27 cytokines. Correlations between the levels of secreted cytokines were altered in the plasma from patients indicating that the immune response regulation was disturbed. Cultivation of the MSCs from the healthy donors in the medium supplemented with the plasma from patients led to the changes in the MSC properties, similar to those observed in the MSCs from patients. The BM-derived MSCs were shown to participate in the humoral changes occurring in the DLBCL patients. For the first time, it was shown that the precursors of the stromal microenvironment - multipotent mesenchymal stromal cells - are altered in the patients with DLBCL without bone marrow involvement due to the humoral effect of the tumor and the response of organism to it. Comprehensive analysis of the results shows that, when remission is achieved in the patients with DLBCL, composition of the plasma cytokines normalizes, but does not reach the level observed in the healthy donors. The discovery of a new aspect of the effect of the tumor B-cells on the organism could help to reveal general regularities of the humoral effect of various tumors on the bone marrow stromal cells.

Analysis of Bone Tissue Condition in Patients with Diffuse Large B-Cell Lymphoma without Bone Marrow Involvement

We studied changes in the bone tissue in patients with diffuse large B-cell lymphoma at the onset of the disease (N=41; before chemotherapy) and 5-16 years after the end of treatment (N=47). Osteodensitometry, biochemical markers of osteoporosis in the blood and urine, and gene expression in multipotent mesenchymal stromal cells were analyzed. In multipotent mesenchymal stromal cells of all patients, the expression of genes associated with bone and cartilage differentiation (FGF2, FGFR1, FGFR2, BGLAP, SPP1, TGFB1, and SOX9) was changed. In primary patients, the ratio of deoxypyridinoline/creatinine in the urine and blood level of β-cross-laps were increased, while plasma concentration of vitamin D was reduced, which indicates activation of bone resorption. No differences between the groups were revealed by osteodensitometry. No direct relationship between changes in gene expression in multipotent mesenchymal stromal cells and osteoporosis markers was found. The presence of a tumor in the body affects the bone marrow stroma, but achievement of remission and compensatory mechanisms provide age-appropriate condition of the bone tissue.