ALBERT

Description: Life-long hematopoiesis depends on the support of mesenchymal stromal cells within the bone marrow (BM). Lymphocytes connect tightly with stromal cells in BM. Leukemia and high dose chemotherapy affected both hematopoietic and stromal precursor cells. Changes in the hematopoiesis that occur during acute lymphoblastic leukemia (ALL) probably correlate with variation in the composition of stromal microenvironment. The aim of the study was to analyze the alterations occurring in stromal precursor cells - colony forming unit fibroblasts (CFU-F) and multipotent mesenchymal stromal cells (MSC) in patients with ALL before and after allogeneic hematopoietic stem cell transplantation (HSCT). HSCT following myeloblative conditioning was performed in 7 ALL patients (6 male, 1 female). After informed consent BM was aspirated before conditioning, and during the year after transplantation. MSC were cultured in aMEM with 10% fetal calf serum. Cumulative MSC production was counted after 5 passages. CFU-F was analyzed in standard conditions. The relative expression level (REL) of different genes was measured by RT-PCR. All data obtained at different time points were analyzed summarily. As a control MSC and CFU-F from 20 healthy donors of BM for HSCT were used after informed consent. The concentration of CFU-F in BM of ALL patients before HSCT was reduced by 12% in comparison with donors. After HSCT the concentration of CFU-F decreased further in 5.2 fold compared to the level before HSCT (p=0.02). Colonies formed by CFU-F depend on autocrine secretion of FGF2. It signals through 2 types of receptors, FGFR1 is considered to be the most important one. REL of FGFR1 was reduced by 27% in colonies from BM of patients before HSCT compared to donors. After HSCT it further decreased 1.2 fold. REL of FGFR2 in colonies of patients decreased 16 fold before and 50 fold after HSCT compared to donors (p=0.01 in both cases). REL of FGF2 in colonies of patients before HSCT doubled compared to donors and decreased 16 fold after HSCT. These data offer the molecular basis of decrease in CFU-F concentration in BM of patients after HSCT. In CFU-F colonies from patients REL of FGFR2 was decreased dramatically, however before HSCT it did not lead to decrease in CFU-F concentration due to increase in REL of FGF2. After HSCT REL of FGF2 and both receptors considerably decreased that led to significant reduction of CFU-F concentration in patients BM. REL of genes-markers of adipogenic and osteogenic differentiations were significantly decreased in CFU-F colonies of patients before HSCT (SPP1 in 8.6 fold, p=0.02, PPARG in 4.7 fold, p=0.01) pointing to less differentiated status of CFU-F progeny. After HSCT REL of these genes increased up to levels higher (PPARG in 3.5 fold, p=0.02) or comparable with donor ones, thus CFU-F seemed to regain “normal” differentiation status. REL of chondrogenic marker SOX9 did not change in CFU-F of ALL patients before and after HSCT, probably due to block of this differentiation lineage in CFU-F. REL of BMP4 in patients’ CFU-F colonies was reduced 30 fold compared to donors (p=0.002), apparently due to damage made by leukemic сells. It increased 100 fold compared to donors after HSCT, that might reflect the intensive recovery of stromal microenvironment by interaction with non-malignant hematopoietic cells. Thus multiple alterations in CFU-F concentration and gene expression were revealed in CFU-F from BM of patients. MSC were also affected in ALL patients. Cumulative cell production in cultures from patients before HSCT was reduced by 35%, while after HSCT the decrease was more pronounced (by 61%, p=0.01). REL of genes regulating the proliferation (FGFR1, FGFR2 and FGF2) in patients MSC was halved in comparison to donors. After HSCT REL of both types of receptors did not change, while REL of FGF2 increased 1.5 fold not reaching donors’ level. The decrease in cumulative cell production could depend on both FGF2 pathway alteration and on the increase of differentiation status in MSC population after HSCT. REL of differentiation markers in MSC before HSCT did not differ from donors’ ones, while after HSCT REL of SPP1 increased 3.8 fold, PPARG – 2.3 fold (p=0.05) and SOX9 in 1.6 fold compared to donors. In patients MSC were less affected by leukemia and its treatment than CFU-F. This data suggest significant damage of stromal precursor cells in ALL patients that lasted at least for one year since HSCT. Disclosures: No relevant conflicts of interest to declare.

Description: The stromal microenvironment regulating hematopoiesis in patients with hematologic malignancies undergoes significant alterations. The changes in the concentration of colony-forming fibroblast units (CFU-F) in the bone marrow (BM) and disruption in the functioning of multipotent mesenchymal stromal cells (MSCs) are shown in many studies for patients with acute leukemia. Often it is not possible to distinguish the cause of changes in stromal progenitor cells after treatment: interaction with tumor cells or the effects of therapy. Most of the patients with diffuse large B-cell lymphoma (DLBCL) do not have BM involvement. It was assumed that the properties of MSCs in these patients were not changed, and so this could be an attractive model for investigation the effect of antitumor drugs on human BM stromal microenvironment. The aim of the study was to compare the properties of MSCs in patients with DLBCL in the onset of the disease and a month after the end of therapy. Methods The study included 20 patients with DLBCL (11 male, 9 female) aged 42-60 years in the onset of the disease and a month after the end of treatment. 3-5 ml of BM were collected during diagnostic punctures after informed consent. MSCs and CFU-F were cultured by standard methods. The total MSCs production, the doubling-population level per day, the concentration of CFU-F, the relative gene expression level (REL) in MSC by real-time PCR and the mean fluorescence intensity (MFI) by flow cytometry were analyzed. The control group included 31 donors of the corresponding age. The analysis of MSCs secretome was carried out using the LC-MS/MS analysis TripleTOF 5600+ mass spectrometer with a NanoSpray III ion source coupled to a NanoLC Ultra 2D+ nano-HPLC System. Results The total cell production for 4 passages in primary patients' MSCs was significantly higher than in donors (11.4 ± 2 x 106 per flask versus 6.9 ± 1.1, p = 0.04). It remained elevated after therapy (10.2 ± 1.5). At the same time, the MSCs population-doubling level per day was significantly decreased in patients in comparison with donors (0.6 ± 0.03 vs. 0.4 ± 0.04, p

Description: Introduction Multipotent mesenchymal stromal cells (MSCs) differentiate into all mesenchymal lineages, regulate hematopoietic stem cells, and also take part in immunomodulation. MSCs are damaged in patients with leukemia. Most of the patients with DLBCL do not have bone marrow (BM) involvement. Despite the absence of proved BM damage in DLBCL patients, the properties of MSCs are changed. We aimed to analyze secretome and transcriptome of MSCs derived from BM of DLBCL patients without BM involvement. Methods The study included 16 DLBCL patients (7 males and 9 females), of which 6 were 42-60-year-old in the onset of the disease and a month after the end of treatment with NHL-BFM90; 10 were 48-78-year-old in complete remission for 6-14 years (5 received CHOP and 5 NHL-BFM90 treatment). Control group included 5 healthy donors (3 males, 2 females), median age 37. During diagnostic punctures BM was collected after informed consent. MSCs were cultured by standard method. Confluent MSCs layers after 1 passage were cultivated in serum-free RPMI1640 without phenol red for 24 hours; supernatants were studied for secretome and cells for transcriptome. The analysis of MSCs secretome was carried out using the LC-MS/MS analysis (TripleTOF 5600+ mass spectrometer with a NanoSpray III ion source coupled to a NanoLC Ultra 2D+ nano-HPLC System. Total RNA was isolated, applying standard procedures, from MSCs. Next-generation sequencing of complementary DNA libraries of polyA-enriched RNA was performed with Illumina HiSeq. Raw RNA-seq data were processed using STAR. Gene expression was compared using the limma R/Bioconductor package. Results The total cell production for 4 passages in primary patients' MSCs was higher than in donors (26.6 ± 2 versus 10.1 ± 4.4 x 106 per flask). It remained elevated regardless of the time passed after therapy. The patterns of secretome and transcriptome of patients' MSCs differed dramatically from the MSCs of healthy donors (Table). In MSCs of primary patients, the secretion and transcription of proteins involved in IL-17, TNF and Toll-like receptor signaling pathways, cytokine-cytokine receptor interaction, cytokine-mediated signaling pathway, cellular response to cytokine stimulus, regulation of signaling receptor activity, regulation of neutrophil chemotaxis, inflammatory and acute inflammatory response and its regulation, leukocyte activation involved in immune response, immune system process, extracellular matrix organization were elevated. Secretion and transcription of cytokines and chemokines (IL6, IL4, LIF, TNFa, CXCL1 and CXCL3), taking part in hematopoiesis regulation were increased in primary patients MSCs. One month after treatment, secretion of 332 proteins was decreased, only 2 of them (DKK1 and FKBP7) were previously overexpressed in primary patients. Many years after the end of both variants of treatment, the secretion and transcription of 32 proteins participating in the same pathways as before treatment remains elevated compared with healthy donors. In addition, the complement and coagulation cascades became upregulated. In MSCs of all patients, regardless of therapy and remission duration , expression/ secretion of following genes/proteins: ACAN, COL1A, MMP3, TGFb1, NDNF, CANX, LAP3, MGP, SERPINB2, STC1,TFPI,TMEM132A, BMP2, CFH, HILPDA, IDO1, IL1B, ITGA2, JUN, LMO2, MMP13, MMP3, TNFRSF1B,TNFSF4 was increased. Some of these proteins take part in bone and cartilage formation, hematopoietic stem cells regulation, blood coagulation and inflammation. These changes in secreted proteins reflect the response of MSCs at the organism level to the tumor presence. Moreover, NUCKS1 overexpression was observed in MSCs of all patients. This nuclear casein kinase plays a significant role in modulating chromatin structure and regulates replication, transcription, and chromatin condensation. Furthermore, this protein contributes to the susceptibility, occurrence, and development of several types of cancer and other diseases. NUCKS1 is considered to be a potent marker for such diseases. Conclusion The presence of a lymphoid tumor without BM involvement in the body leads to irreversible changes in the BM MSCs, thus affecting a lot of biological processes and signaling pathways, independent of the treatment and duration of complete remission. The work were supported by the Russian Foundation for Basic Research, Project No. 17-00-00170. Disclosures No relevant conflicts of interest to declare.

Description: Introduction Allogeneic bone marrow transplantation (allo-BMT) is currently the only way to cure many hematoproliferative disorders. However, allo-BMT use is limited by severe complications, among which the most challenging is graft-versus-host disease (GVHD). As the conventional methods of GVHD prophylaxis are often inefficient new method involving the use of donors’ multipotent mesenchymal stromal cells (MSC) was developed. In some cases prophylaxis of acute GVHD (aGVHD) failed. The reasons of the failure could be either the result of particular qualities of donor-recipient interaction, patient status or characteristics of MSC samples. The results of the aGVHD prophylaxis with donors’ MSC injections after allo-BMT in patients with hematological malignancies included in the randomized clinical trial (Clinicaltrials.gov NCT01941394) were analyzed. In order to discriminate between effective and ineffective for aGVHD prophylaxis MSC samples were thoroughly analyzed. The growth and differentiation characteristics, relative expression levels of different genes were investigated in all MSC samples. Methods The study included 77 patients who received allo-BMT from related donors after informed consent. The patients were randomized into 2 groups: the first received standard prophylaxis of aGVHD and the second were additionally infused with MSC from the bone marrow of corresponding hematopoietic stem cells donor at day of WBC reconstitution 〉1*109/l. MSC were cultivated in aMEM with 4% donors’ platelet lysate. MSC were administered intravenously when the blood counts indicated recovery (peripheral blood leukocytes reached 1x109/l). MSCs and colony-forming unit-fibroblasts (CFU-Fs) from the bone marrow of those donors were analyzed. For this purpose MSC were cultivated in standard conditions (aMEM, 10% fetal calf serum) for 5 passages. Relative expression level (REL) of 30 genes involved in proliferation, differentiation and immunomodulation was estimated by RT-qPCR in all MSC samples. Results The infusion of MSC reduced the incidence of aGVHD 2 times and increased the 5 years overall survival of patients (p=0.047). Four of 39 MSC samples have been ineffective for preventing aGVHD. Analysis of individual donor characteristics (gender, age, body mass index), the MSC properties of these donors (growth parameters, REL of 30 genes involved in proliferation, differentiation and immunomodulation) found no significant differences between the MSC, effective and ineffective for preventing aGVHD. However the analysis revealed that cumulative MSC production and CFU-F concentrations in bone marrow decreased with donor age. MSC populations revealed the hierarchy that changed during cultivation, resulting in an increase in the impact of mature cells and a decrease in the subpopulation of cells with high proliferation potential. The combination of predictors that characterize the most suitable for the prevention of aGVHD MSC samples was revealed by multiple logistic regression analysis. A model calculating the probability of the success of MSC samples application was proposed: logit(P)=0,75+10,897*FGFR1-4,272*PPARG-2,014*IGF1, where logit(P) = ln[P/(1-P)], P – probability of successful prophylaxis, FGFR1, PPARG and IGF1 – REL of corresponding genes in tested MSC sample. Chi-square goodness of fit test p= 0.0053. The calculated efficiency of this model was 94%. The following parameters of MSC were essential for the success of aGVHD prophylaxis: increased REL of FGFR1 combined with reduced REL of PPARG and IGF1 genes. Depending on the chosen value for probability of successful application of MSC, this model can correctly predict the outcome of the use of MSC in 82-94% of cases. Conclusions These data confirm the presence of hierarchy as well as heterogeneity in MSC population. The high variability of all analyzed characteristics among MSC from different donors was shown. The mathematical model revealed the combination of parameters enabling to distinguish effective and ineffective MSC samples. By means of the proposed model ineffective MSC samples could be discharged and replaced by effective MSC sample from the third part donor. Such strategy hopefully will prevent the development of aGVHD in the maximum number of patients. Disclosures No relevant conflicts of interest to declare.