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.

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.

[Multipotent mesenchymal stromal cells application for acute graft versus host disease treatment].

AIM: Analysis of the effectiveness of the MSCs aministration as the second- or third-line therapy of acute GVHD (aGVHD) resistant to glucocorticosteroid treatment. MATERIALS AND METHODS: The study included 35 patients who received MSCs obtained from the bone marrow of healthy donors as a treatment of steroid-resistant aGVHD. The clinical parameters of patients, MSCs cultural characteristics, the MSC expression profile for various genes including those involved in immunomodulation, expression of cells surface markers, the source of MSCs, as well as the frequency and number of MSC administrations were analyzed. RESULTS: Response to therapy was achieved in 74% of cases, a complete response was reached in 13 (37%) patients, partial response/clinical improvement was demonstrated in 13 (37%). This treatment was ineffective in 9 patients. The prediction of a group of patients with good response to MSC therapy turned to be impossible. The differences between the effective and ineffective for the GVHD treatment MSCs samples were found. The effective ones were characterized with a decreased total MSCs production and an increase in the main histocompatibility complex and PDL-1 antigens expression. CONCLUSION: These data allow to select optimal samples for aGVHD treatment that can improve clinical results. aGVHD treatment with MSCs has shown efficacy comparable to other treatment approaches. Given the low percentage of complications and the absence of significant adverse effects, MSC therapy seems to be one of the optimal approaches to the treatment of resistant forms of GVHD.

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 ß-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.

Multipotent Mesenchymal Stromal Cells in Patients with Chronic Myeloid Leukemia before Discontinuation of Tyrosine Kinase Inhibitors.

We analyzed changes in multipotent mesenchymal stromal cells of patients with chronic myeloid leukemia before discontinuation of tyrosine kinase inhibitors. Withdrawal syndrome was significantly more common in patients who have been taking tyrosine kinase inhibitors for a longer time and in patients of older age and with lower body weight. In patients with withdrawal syndrome, the total production of mesenchymal stromal cells and expression of FGFR2 and MMP2 genes were significantly lower; loss of deep molecular response was also less frequent in this group of patients. At the same time, the expression of genes important for the maintenance of stem cells (SOX9, PDGFRa, and LIF) was significantly lower in the mesenchymal stromal cells of patients with withdrawal syndrome and loss of deep molecular response. We observed a clear-cut relationship between the development of withdrawal syndrome and the loss of deep molecular response. The decrease in the expression of FGFR2 and MMP2 genes in the mesenchymal stromal cells of patients with chronic myeloid leukemia before discontinuation of treatment can be a predictor of withdrawal syndrome, while simultaneous decrease in the expression of SOX9, PDGFRa, and LIF in these cells attests to undesirability of therapy discontinuation at the moment.

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

In diffuse large B-cell lymphoma, bone marrow involvement is rarely diagnosed. We compared the properties of bone marrow stromal progenitor cells and the concentration of fibroblast CFU in patients with diffuse large B-cell lymphoma without bone marrow involvement and in healthy donors. It was found that the properties of multipotent mesenchymal stromal cells in patients in the debut of the disease differed considerably from those in healthy donors. In particular, the total cell production in patients was significantly higher than in donors. In multipotent mesenchymal stromal cells of patients, some cell parameters were changes; the mean fluorescence intensity of the adhesion molecule ICAM1 on the cell surface was increased. The mean fluorescence intensity of mesenchymal stromal cell markers (HLA-ABC, CD73 and CD90) was significantly elevated. The relative expression of BMP4, MMP2, FGFR1, and ICAM1 genes in mesenchymal stromal cell was reduced, while the expression of FGFR2 gene was enhanced. Despite the absence of proven involvement of the bone marrow, the properties of mesenchymal stromal cells, the components in the stromal microenvironment niche regulating hemopoiesis are altered in patients with diffuse large B-cell lymphoma.

Clonal Composition of Human Multipotent Mesenchymal Stromal Cells: Application of Genetic Barcodes in Research.

Clonal composition of human multipotent mesenchymal stromal cells (MMSCs) labeled with lentiviral vectors carrying genetic barcodes was studied. MMSCs were transduced with a cloned library of self-inactivating lentiviral vectors carrying 667 unique barcodes. At each cell culture passage, 120 cells were plated one cell per well in 96-well plates. The efficiency of cloning and labeling of the clonogenic cells was determined. DNA was extracted from the cell-derived colonies, and the barcodes were identified by Sanger sequencing. Also, DNA was extracted from the total MMSC population at each passage to analyze the diversity and representation of barcodes by deep sequencing using the Illumina platform. It was shown that the portion of MMSCs labeled with the lentiviral vectors remained stable in the passaged cells. Because of the high multiplicity of infection, the labeling procedure could decrease the proliferative potential of MMSCs. Identification of barcodes in individual cell clones confirmed the polyclonal character of the MMSC population. Clonal composition of MMSCs changed significantly with the passages due to the depletion of proliferative potential of most cells. Large clones were found at the first passage; at later passages, many small clones with a limited proliferative potential were detected in the population. The results of deep sequencing confirmed changes in the clonal composition of MMSCs. The polyclonal MMSC population contained only a small number of cells with a high proliferative potential, some of which could be stem cells. MMSCs with a high proliferative potential were detected more often in the earliest passages. In this regard, we would recommend to use MMSCs of early passages for regenerative medicine applications based on cell proliferation.

Individual Differences of Multipotent Mesenchymal Stromal Cells Manifesting in during Interaction with Lymphocytes.

Analysis of changes in lymphocyte subpopulations during co-culturing with multipotent mesenchymal stromal cells (MSC) revealed two distinct MSC groups: one group (A) increased HLA-DR expression on lymphocytes during co-culturing and the other (B) did not change it in comparison with lymphocyte monoculture. In stromal cells interacting with lymphocytes, expression of HLA-DR molecules was initiated, but only in samples that induced enhanced expression on lymphocytes and irrespectively of whether allogeneic or autologous lymphocytes were used for co-culturing with MSC. In group A, the relative expression of IDO1 significantly increased in comparison with group B. The revealed individual differences in MSC can explain why not all MSC samples are effective in the treatment of autoimmune diseases, acute "graft-versus-host" disease, and other pathologies.

Investigation of the Mesenchymal Stem Cell Compartment by Means of a Lentiviral Barcode Library.

The hematopoietic bone marrow microenvironment is formed by proliferation and differentiation of mesenchymal stem cells (MSCs). The MSC compartment has been less studied than the hematopoietic stem cell compartment. To characterize the structure of the MSC compartment, it is necessary to trace the fate of distinct mesenchymal cells. To do so, mesenchymal progenitors need to be marked at the single-cell level. A method for individual marking of normal and cancer stem cells based on genetic "barcodes" has been developed for the last 10 years. Such approach has not yet been applied to MSCs. The aim of this study was to evaluate the possibility of using such barcoding strategy to mark MSCs and their descendants, colony-forming units of fibroblasts (CFU-Fs). Adherent cell layers (ACLs) of murine long-term bone marrow cultures (LTBMCs) were transduced with a lentiviral library with barcodes consisting of 32 + 3 degenerate nucleotides. Infected ACLs were suspended, and CFU-F derived clones were obtained. DNA was isolated from each individual colony, and barcodes were analyzed in marked CFU-F-derived colonies by means of conventional polymerase chain reaction and Sanger sequencing. Barcodes were identified in 154 marked colonies. All barcodes appeared to be unique: there were no two distinct colonies bearing the same barcode. It was shown that ACLs included CFU-Fs with different proliferative potential. MSCs are located higher in the hierarchy of mesenchymal progenitors than CFU-Fs, so the presented data indicate that MSCs proliferate rarely in LTBMCs. A method of stable individual marking and comparing the markers in mesenchymal progenitor cells has been developed in this work. We show for the first time that a barcoded library of lentiviruses is an effective tool for studying stromal progenitor cells.

Long-term survival of donor bone marrow multipotent mesenchymal stromal cells implanted into the periosteum of patients with allogeneic graft failure.

The present study involved three patients with graft failure following allogeneic hematopoietic stem cell transplantation (allo-HSCT). We obtained multipotent mesenchymal stromal cells (MSCs) from the original hematopoietic cell donors and implanted these cells in the periosteum to treat long-term bone marrow aplasia. The results showed that in all patients endogenous blood formation was recovered 2 weeks after MSC administration. Donor MSCs were found in recipient bone marrow three and 5 months following MSC implantation. Thus, our findings indicate that functional donor MSCs can persist in patient bone marrow.

Stable Lentiviral Vector Transfer into Mesenchymal Stem Cells In Vivo.

Green fluorescent protein (eGFP) gene was transferred into mouse mesenchymal stem cells in vivo using a lentiviral vector. In 2 months after injection of the lentivirus into the cavity of the femoral bone, up to 30% fibroblast CFU in the bone marrow of infected mice contained the alien gene. The transferred gene was found in more than 50% of adherent layers of longterm bone marrow cultures formed by mesenchymal stem cells from the infected mice bone marrow; 4% fibroblast CFU obtained from these layers were labeled. Ectopic hemopoiesis foci developed after transplantation of the bone marrow from infected mice under the renal capsule of syngeneic recipients contained bone tissue labeled with the alien gene in 57% cases and labeled fibroblast CFU in 11%. The data confirm the possibility of gene transfer with the lentiviral vectors into the mesenchymal stem cells in vivo.

Peculiarities of Gene Transfer into Mesenchymal Stem Cells.

Murine mesenchymal stem cells in long-term bone marrow culture were genetically labeled using lentiviral vector carrying enhanced green fluorescent protein (eGFP) reporter gene under SFFV promoter or without it. We studied the developmental fate of labeled mesenchymal stem cells in stromal cell layers of long-term bone marrow culture and in ectopic hemopoietic foci formed by these stromal layers under the renal capsule of syngeneic mice. The frequency of labeled polypotent stromal precursors (fibroblast CFU) was analyzed in adherent cell layers of long-term culture and ectopic foci formed from them. The proportion of labeled fibroblast CFU in ectopic foci increased by 10 times in case of implantation of adherent cell layers infected with lentivirus containing eGFP reporter gene without promoter. eGFP expression leads to rejection of labeled stromal cells. Labeling with eGFP-carrying vector without promoter makes possible long-term tracking of mesenchymal stromal cells.

Proliferative potential of multipotent mesenchymal stromal cells from human bone marrow.

We studied the capacity of multipotent mesenchymal stromal cells isolated from human bone marrow (BM) to long-term passaging, cloning, and re-cloning. Initial multipotent mesenchymal stromal cells and cells after gene labeling were studied. Multipotent mesenchymal stromal cells were obtained from donors (13-59 years) and cultured for 7 passages. Third generation lentivector was used for delivery of green fluorescent protein marker gene. The procedure of infection revealed reduced proliferative potential of multipotent mesenchymal stromal cells from elder donors. Hierarchy of precursor cells differing by their proliferative potential was demonstrated in the culture of multipotent mesenchymal stromal cells. Three categories of multipotent mesenchymal stromal cells were identified: mature cells incapable of proliferation (75.7±2.4% population) and cells with low and high proliferative potential (17.6±2.1 and 6.7±0.3%, respectively). The relative content of these cells insignificantly differed from passage to passage. The efficiency of cloning also remains stable, but re-cloning capacity sharply decreased after passage 3 and completely disappeared in multipotent mesenchymal stromal cells after cryopreservation. Thus, cultured multipotent mesenchymal stromal cells represent a heterogeneous and hierarchically organized population and the characteristics of this population depend of the duration of culturing and age of BM donor. This should be taken into account when using multipotent mesenchymal stromal cells in clinical practice.

Characteristics of mesenchymal stromal precursor cells labeled with lentiviral vector in long-term bone marrow culture.

Mouse mesenchymal stromal precursor cells were labeled with lentiviral vector in long-term bone marrow culture. We studied the fate of labeled cells in the stromal sublayer of the long-term bone marrow culture and in ectopic hemopoiesis foci formed from the labeled cultures. The incidence of labeled polypotent fibroblast CFU in sublayers of long-term bone marrow culture and in ectopic hemopoiesis foci formed from these sublayers under the renal capsule of syngeneic mice was also analyzed. It was shown that the marker gene was present in about 40% cells of the stromal sublayer and 30% fibroblast CFU and that effective gene transfer did not affect the total production of hemopoietic cells. The size of ectopic hemopoietic foci formed after implantation of labeled sublayers of the long-term bone marrow culture under the renal capsule did not differ from the control. Differentiated cells of the osseous shell in these foci carried the marker gene in 40% cases. Analysis of fibroblast CFU in these foci showed that despite the total concentration of fibroblast CFU was comparable to that in the bone marrow, the concentration of labeled fibroblast CFU was about 6%, which suggests that one more class of precursors probably exists in the hierarchy of stromal cells presumably between mesenchymal stem cells and fibroblast CFU. Our findings demonstrate the capacities of mesenchymal stem cells to self-maintenance and differentiation without losing the marker gene integrated into the genome.

Characteristics of transplanted mouse myeloproliferative disease developed after repeated injections of granulocytic colony-stimulating factor.

Transplanted myeloproliferative disease developed in mice against the background of repeated injections of granulocytic CSF was characterized using morphological and molecular biological methods. It was demonstrated that transplanted myeloproliferative disease had a non-viral nature and is probably induced by repeated injections of granulocytic CSF. Tumor cells actively populate the liver of sick animals, which leads to their rapid death. Expression of Myc, Abl, G-CSF, and MPO genes is enhanced, which is typical of myeloid neoplastic transformation.

Infection of stromal and hemopoietic precursor cells with lentivirus vector in vivo and in vitro.

We developed a method for gene transfer into mesenchymal stromal cells. Lentivirus vector containing green fluorescent protein gene for labeling stromal and hemopoietic precursor cells was obtained using two plasmid sets from different sources. The vector was injected into the femur of mice in vivo and added into culture medium for in vitro infection of the stromal sublayer of long-term bone marrow culture. From 25 to 80% hemopoietic stem cells forming colonies in the spleen were infected with lentivirus vector in vivo and in vitro. Fibroblast colony-forming cells from the femoral bones of mice injected with the lentivirus vector carried no marker gene. The marker gene was detected in differentiated descendants from mesenchymal stem cells (bone cavity cells from the focus of ectopic hemopoiesis formed after implantation of the femoral bone marrow cylinder infected with lentivirus vector under the renal capsule of syngeneic recipient). In in vitro experiments, the marker gene was detected in sublayers of long-term bone marrow cultures infected after preliminary 28-week culturing, when hemopoiesis was completely exhausted. The efficiency of infection of stromal precursor cells depended on the source of lentivirus. The possibility of transfering the target gene into hemopoietic precursor cells in vivo is demonstrated. Stromal precursor cells can incorporate the provirus in vivo and in vitro, but conditions and infection system for effective infection should be thoroughly selected.

[Inheritable phenotypic normalization of rodent cells transformed by simian adenovirus SA7 E1 oncogenes by singled-stranded oligonucleotides complementary to a long region of integrated oncogenes]. / Nasleduemaia fenotipicheskaia normalizatsiia transformirovannykh E1 onkogenami adenovirusa obez'ian SA7 kletok gryzunov odnotiazhevymi oligonukleotidami, komplementarnymi protiazhennym uchastkam integrirovannykh onkogenov.

G11 mouse cells and SH2 rat cells transformed with simian adenovirus SA7 DNA showed inheritable oncogen-specific phenotypic normalization when treated with sense and antisense oligonucleotides complementary to long RNA sequences, plus or minus strands of the integrated adenovirus oncogenes E1A and E1B. Transitory treatment of the cells with the oligonucleotides in the absence of serum was shown to cause the appearance of normalized cell lines with fibroblastlike morphology, slower cell proliferation, and lack of ability to form colonies in soft agar. Proliferative activity and adhesion of the normalized cells that established cell lines were found to depend on the concentration of growth factors in the cultural medium. In some of the cell lines, an inhibition of transcription of the E1 oncogenes was observed. The normalization also produced cells that divided 2 - 5 times and died and cells that reverted to a transformed phenotype in 2 - 10 days. The latter appeared predominantly upon the action of the antisense oligonucleotides.

[Nucleotide sequence of the E1B area and the adjacent 3'-terminal segment of the E1A oncogene from monkey adenovirus SA7 (C8)]. / Nukleotidnaia posledovatel'nost' oblasti E1B i primykaiushchego k nei 3'-kontsevogo uchastka oblasti E1A onkogena adenoviursa obez'ian SA7 (C8).

The SA7 (C8) simian adenovirus was sequenced from the 1478th to 3194th nucleotide. The region includes the 3'-terminal part of E1A and the major part of the E1B coding region. The sequence obtained was compared with the structure of SA7 (P) DNA previously determined in the region 1-2338, and many differences were found which are nucleotide substitutions, microdeletions and microinsertions. Among point substitutions the most frequent was the C-->T transition in CG pairs known as hot spots of mutations. Differences of our sequence from the previously published one was also revealed.