Natalizumab Increases Circulating CD34+ Cells with An Impaired Functional Potential In Patients with Multiple Sclerosis without Affecting the Bone Marrow.

Abstract Abstract 2620 Introduction: In our previous report (Zohren et al., Blood 2008) we could show that the blockade of the heterodimer VLA-4 by the monoclonal IgG4 antibody natalizumab leads to a significant increase in circulating CD34+ cells in patients with multiple sclerosis (MS). We now extend our analysis on the influence of natalizumab on CD34+ cells comparing bone marrow (BM) and peripheral blood (PB) derived CD34+ cells of natalizumab patients with those from healthy donors. Methods: A total of 83 patients with MS receiving natalizumab were included. In vitro adhesion, migration and apoptosis assays as well as LTC-IC of immunomagnetically enriched CD34+ cells were conducted. Flow cytometric analyses were performed to assess phenotype and composition of the CD34+ subsets. Results: The median concentration of circulating CD34+ cells was significantly greater compared to normal donors (7.7/μL vs. 1.8/μ L; p= 0.0001) and remained relatively stable during a one year treatment with natalizumab. Leukocyte cell counts, the number of T cell subsets as well as the number of CD19+ B cells and CD56+ natural killer cells were in normal range in PB and BM after short- and long-term treatment with natalizumab. However, we found significantly reduced adhesion and migration abilities of circulating CD34+ cells under natalizumab treatment in comparison to G-CSF mobilized CD34+ cells of healthy donors. Moreover, the self-renewal capacity of these cells was poor. In contrast, no significant difference was seen between the BM of natalizumab patients and the BM of healthy donors with regard to cellularity and proportion of CD34+ cells. In addition, neither co-expression of CD49d nor the adhesion ability of the BM derived CD34+ cells revealed a significant difference between the two collective. Conclusions: Our data indicate that natalizumab mediates an increase in circulating CD34+ cells by impaired homing. These findings argue against the use of natalizumab-exposed PB CD34+ cells for transplantation. Disclosures: No relevant conflicts of interest to declare.

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Comparative Analysis on Cellular Components of Bone Marrow Microenvironment in Normal and Aberrant Hematopoiesis

Blood ◽

10.1182/blood.v118.21.4808.4808 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4808-4808

Author(s):

Young-Ho Lee ◽

Young-hee Kwon ◽

Kyoujung Hwang ◽

Hyunju Jun ◽

Byungbae Park ◽

...

Keyword(s):

Bone Marrow ◽

T Cell ◽

Conflicts Of Interest ◽

T Cell Subsets ◽

Hematopoietic Stem ◽

Cd34 Cells ◽

Significant Difference ◽

Stromal Cell Derived Factor ◽

And Control ◽

Cellular Components

Abstract Abstract 4808 Background: It is now evident that hematopoietic stem cells (HSCs) reside preferentially at the endosteal region within the bone marrow (BM) where bone-lining osteoblasts are a key cellular component of the HSC niche that directly regulates HSC fate. We investigated the microenvironmental differences including osteoblastic activities and HSC components in myeloproliferative (chronic myeloid leukemia, CML) and hypogenerative disease (aplastic anemia, AA) as well as normal control (NC). Methods: The immunohistochemistry for osteonectin, osteocalcin, stromal cell derived factor (SDF, CXCL12), T cell, T helper/inducer cell, T suppressor/cytotoxic cell, hematopoietic stem/progenitor (CD34, CD117) and megakaryocytes was performed on BM biopsy specimens from 10 AA patients, 10 CML patients and 10 NC (lymphoma without BM involvement). The positive cells for immunohistochemical stainings except osteocalcin on each slide were calculated on 10 high power fields (HPF, ×400), and then corrected by the cellularity. The positive cells for osteocalcin were counted on the peritrabecular line on each slide, and then corrected by the mean length measured. Results: The CD34+ cells (p=0.012) and megakaryocytes (p<0.0001) were significantly lower in AA than in NC, but CD117+ cells was comparable in AA, CML, and control samples. The osteonectin+ cells (p=0.0003) were lower in CML than in AA and NC, however the osteocalcin+ cells showed wide variation (0-903/2035um) and no significant difference. The SDF+ cells (p<0.0001) was significantly higher in AA and very lower in CML, compared with NC. The counts for T cell and T cell subsets were significantly lower in CML than in NC, and higher in AA than in NC (p<0.0001). Conclusions: Cellular components of BM microenvironment in 2 hematologic diseases representative of myeloproliferation (CML) and hyporegeneration (AA) respectively are quite different. Further studies would be required to explore the role of these components for hematopoiesis and the rationale for therapeutic application. Disclosures: No relevant conflicts of interest to declare.

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Pro- and Antiapoptotic Proteins Expression on Bone Marrow and Peripheral Blood CD34+Cells in Acute Leukemia (AL) Patients

Blood ◽

10.1182/blood.v118.21.4996.4996 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4996-4996

Author(s):

Elena E. Khodunova ◽

Elena N Parovichnikova ◽

Irina V. Galtzeva ◽

Sergey M. Kulikov ◽

Valeri G Savchenko

Keyword(s):

Bone Marrow ◽

Peripheral Blood ◽

Conflicts Of Interest ◽

Expression Level ◽

Leukemia Cells ◽

Control Group ◽

Healthy Donors ◽

Cd34 Cells ◽

Significant Difference ◽

Blast Cells

Abstract Abstract 4996 It was shown that drug resistance, poor-risk cytogenetics and poor prognosis in AL is associated with high level of Bcl-2 expression and low Bax/Bcl-2 ratio (<0,3). Fas-antigen (CD95) as a protein triggering the extrinsic apoptotic pathway is differently expressed on hematopoietic precursors. More immature CD34+/CD38- AML blast cells have lower expression of Fas/Fas-L and lower Fas-induced apoptosis than CD34+/CD38+cells. CD34+/CD38− leukemia precursors also have a reduced sensitivity to daunorubicin in vitro and increased expression of multidrug resistance genes (mrp/lrp). CD34+ leukemia cells have not yet been properly characterized regarding the expression of angiotensin converting enzyme (ACE) which regulatory influence on hematopoiesis is now beeing extensively investigated. ACE expression on blast cells is high, but it's still unknown how CD34+ACE+ leukemia cells behave after chemotherapy. Recent publications indicate that CD34+ACE+ hematopoietic precursors transplanted into NOD/SCID mice contribute 10-fold higher numbers of multilineage blood cells than their CD34+ACE- counterparts. We have studied the dynamics of Bcl-2, Bax, CD95 and ACE expression on CD34+ cells in peripheral blood (PB) and bone marrow (BM) in AL pts during treatment. PB and BM samples were collected before and on +36 day after chemotherapy. The antigens were detected by flow cytometry using monoclonal antibodies. We calculated 10 000 cells in each sample. 19 pts were included in the study: 10 - AML and 9 - ALL. The control group comprised 8 healthy donors. At time of diagnosis there were 40±5,7% of CD34+ cells in BM and 26±4,9% - in PB. There was no significant difference between AML and ALL. CD34+ cells in BM and PB of healthy donors constituted 1,6% and 0,27%, respectively. After induction therapy (+36 day) CD34+ cells decreased in BM to 6,1%±3,3 (p=0,0001), in PB to 3,7%± 2,7 (p=0,0008) in all pts. The data on antigens expression on CD34+ cells of BM and PB are presented in table 1 CD34+/Bcl-2+ CD34+/Bax+ CD34+/CD95+ CD34+/ACE+ BM PB BM PB BM PB BM PB AML pts n=10 0 day 38±11,6* 41±14 24,4±7,9 29,2±7,6* 16,4±8,5 23,2±7,8 21,7±9,5 20,8±8,7* 36 day 13,5±3,4** 23,7±5** 46,2±11,5 50,3±11 19,9±5,5 36,4±10 34±6,6 35±9,2** ALL pts n=9 0 day 36±11 33,7±12 46,2±9,4 37,4±3,7* 3,4±1,1* 7,1±2,5* 41±10,9 33,2±9,7* 36 day 18,4±5,8 26±8,9 38±11,8 40,5±10 26,2±9,1** 40,9±9,2** 34±10 62,8±10** Donors n=8 11,7±1,6 26,1±5,9 22,8±4 67,8±6,7 13,4±3,2 47,7±11,6 28±5,3 68,2±10,2 * − p<0.05 compare with donors ** − p<0.05 compare with day 0 CD34/Bcl-2 expression in BM in AML pts is significantly higher (p=0,04) at the diagnosis comparing with donors. CD34/Bcl-2 expression in PB in AML pts and in BM and PB in ALL pts is higher too, but not significantly. This expression level decreased substantially in BM and PB in AML pts on +36 day comparing with day 0 (p<0,05). We did not found significant changes in ALL pts. CD34/Bax expression in PB is significantly lower (p=0,003) both in AML and ALL pts in comparison with donors. In AML, not in ALL, chemotherapy caused augmentation of Bax expression in CD34+ BM and PB cells on +36 day. BM and PB CD34+ cells in donors had different expression characteristics of Bcl-2 and Bax, demonstrating much higher level of pro- and antiapoptotic markers in PB cells. On the contrast CD34+ leukemia cells in BM and PB had similar characteristics regarding CD34/Bcl-2 and CD34/Bax expression. This fact demonstrates the heterogeneity of donor CD34+cells in BM and PB and points that leukemia CD34+cells in BM and PB are rather similar. CD95 expression on CD34+ BM and PB before treatment is significantly lower (p=0,01, p=0,008) in ALL pts in comparison with donors, and this expression level increased after chemotherapy (p<0,05). CD34/CD95 expression in AML pts is similar with donors, and we didn't find changes after treatment. CD34/ACE coexpression in BM cells of leukemia pts and donors did not differ much at any time of evaluation. But CD34/ACE expression in PB cells of AML and ALL pts was much lower (p<0,05) than in donors and substantially increased on the day 36. So, our data demonstrate that Bcl-2, Bax, CD95 and ACE expression on CD34+ cells in AL pts and donors significantly differs. The chemotherapy provokes critical changes in CD34/CD95 expression in BM and PB in ALL pts, CD34/Bcl-2 expression in AML pts and ÑÂ34/ACE expression in PB in all AL pts. Disclosures: No relevant conflicts of interest to declare.

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Mesenchimal Stroma Cells From Patients with Myelodysplastic Syndrome and Acute Myeloid Leukemia Show Distinct Cytogenetic and DNA-Mutation Data as Compared with Bone Marrow Leukemic Blasts.

Blood ◽

10.1182/blood.v114.22.4697.4697 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4697-4697

Author(s):

Olga Blau ◽

Wolf-Karsten Hofmann ◽

Claudia D Baldus ◽

Gundula Thiel ◽

Florian Nolte ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Control Analysis ◽

Npm1 Mutation ◽

Dna Mutation ◽

Healthy Donors ◽

Acute Myeloid

Abstract Abstract 4697 Bone marrow mesenchymal stroma cells (BMSC) are key components of the hematopoietic microenvironment. BMSC from patients with acute myeloid leukemia (AML) and myelodisplasic syndrome (MDS) display functional and quantitative alterations. To gain insight into these questions, we carried out cytogenetic analyses, FISH, FLT3 and NPM1 mutation examinations of both hematopoietic (HC) and BMSC derived from 53 AML and 54 MDS patients and 35 healthy donors after in vitro culture expansion. Clonal chromosomal aberrations were detectable in BMSC of 12% of patients. Using FISH we have assume that cytogenetic markers in BMSC were always distinct as the aberrations in HC from the same individual. 17% and 12% of AML patients showed FLT3 and NPM1 mutations in HC, respectively. In BMSC, we could not detect mutations of NPM1 and FLT3, independent from the mutation status of HC. For control analysis, BMSC cultures from 35 healthy donors were prepared under the same conditions. BMSC from healthy donors did show normal diploid karyotypes and absence of specific DNA-mutations of NPM1 and FLT3. Our data indicate that BMSC from MDS and AML patients are not a part of malignant clone and characterized by genetic aberrations. Lack of aberrations as detected in HC and appearance of novel clonal rearrangements in BMSC may suggest enhanced genetic susceptibility and potential involvement of BMSC in the pathogenesis of MDS and AML. Disclosures: No relevant conflicts of interest to declare.

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Prolonged Thrombocytopenia After Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT) and Its Association with an Increase in CD8+ CX3CR1+ Cells in Bone Marrow.

Blood ◽

10.1182/blood.v120.21.3077.3077 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3077-3077

Author(s):

Xiao-hui Zhang ◽

Guo-xiang Wang ◽

Yan-rong Liu ◽

Lan-Ping Xu ◽

Kai-Yan Liu ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Surface Expression ◽

T Cell Subsets ◽

Control Group ◽

Hematopoietic Stem ◽

Cell Counts

Abstract Abstract 3077 Background: Since prolonged thrombocytopenia (PT) is an independent risk factor for poor clinical outcome after allogeneic hematopoietic stem cell transplantation (allo-HSCT), the underlying mechanisms need to be understood in order to develop selective treatments. Previous studies1–4 have suggested that abnormalities in B cells may play a role in the pathogenesis of PT. However, abnormalities in B cells alone do not fully explain the complete pathogenic mechanisms of PT. Our previous studies5 showed that the frequency of megakaryocytes with a ploidy value ≤ 8N was significantly increased in patients who developed PT after allo-HSCT compared to the control group. Mechanisms concerning the megakaryocyte hypoplasia in PT after allo-HSCT are not well understood. Design and Methods: PT was defined as a platelet count ≤80 × 109/L for more than 3 months after HSCT, recovery of all other cell counts, and no apparent cause for thrombocytopenia, such as aGVHD, disease recurrence, CMV infection, or antiviral drug treatment at three months post-HSCT when all other blood cell counts had return to normal.5 We analyzed T cell subsets in bone marrow (BM) and peripheral blood (PB) from allo-HSCT recipients with and without PT (n = 23 and 17, respectively) and investigated the expression characteristics of homing receptors CX3CR1, CXCR4 and VLA-4 by flow cytometry. Futhermore, Mononuclear cells (MNCs) from PT patients and controls were cultured with and without autologous CD8+ T cells in vitro, and clarify the effect of activated CD8+ T cells on the ploidy and apoptosis of megakaryocytes in the bone marrow. Results: The results demonstrated that the percentage of CD3+ T cells in the BM was significantly higher in PT patients than the experimental controls (76.00 ± 13.04% and 57.49 ± 9.11%, respectively, P < 0.001), whereas this difference was not significant for the PB (71.01 ± 11.49% and 70.49 ± 12.89%, respectively, P = 0.911). While, some T cell subsets in the BM and PB from allo-HSCT recipients with PT were not significantly different from that of the experimental control group, such as CD8+ T cells, CD4+ T cells, CD4+ CD25bright T cells (regulatory T cells), CD44hi CD62Llo CD8+ T cells and naive T cells (CD11a+ CD45RA+). Furthermore, the surface expression of homing receptor CX3CR1 on BM T cells (64.16 ± 14.07% and 37.45 ± 19.66%, respectively, P < 0.001) and CD8+ T cells (56.25 ± 14.54% and 35.16 ± 20.81%, respectively, P = 0.036), but not in blood, were significantly increased in PT patients compared to controls. For these two groups of patients, the surface expression of CXCR4 and VLA-4 on T cells and CD8+ T cells from both BM and PB did not show significant differences. Through the study in vitro, we found that the activated CD8+ T cells in bone marrow of patients with PT might suppress apoptosis (MNC group and Co-culture group: 18.02 ± 3.60% and 13.39 ± 4.22%, P < 0.05, respectively) and Fas expression (MNC group and Co-culture group: 21.10 ± 3.93 and 15.10 ± 2.33, P <0.05, respectively) of megakaryocyte. In addition, megakaryocyte with a ploidy value ≤ 8N (MNC group: 40.03 ± 6.42% and 24.54 ± 4.31%, respectively, P < 0.05) was significantly increased in patients with PT compared to the control group. Conclusions: In conclusion, an increased surface expression of CX3CR1 on T cells may mediate the recruitment of CD8+ T cells into the bone marrow in patients with PT who received an allo-HSCT. Moreover, CD8+CX3CR1+ T cells, which can have significantly increased numbers in bone marrow of patients with PT, likely caused a reduction in the megakaryocyte ploidy, and suppressed megakaryocyte apoptosis via CD8+ T cell-mediated cytotoxic effect, possibly leading to impaired platelet production. Therefore, treatment targeting CX3CR1 should be considered as a reasonable therapeutic strategy for PT following allo-HSCT. Disclosures: No relevant conflicts of interest to declare.

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IL-6 Deficiency Reverses Leukemic Transformation in an MDS Mouse Model

Blood ◽

10.1182/blood-2020-137026 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 36-36

Author(s):

Yang Mei ◽

Yijie Liu ◽

Xu Han ◽

Jing Yang ◽

Peng Ji

Keyword(s):

Bone Marrow ◽

Mouse Model ◽

Inflammatory Cytokines ◽

Conflicts Of Interest ◽

Double Knockout ◽

Leukemic Transformation ◽

Hematopoietic Stem ◽

Cell Counts ◽

Age Related

Myelodysplastic syndromes (MDS) are a group of age-related myeloid malignancies that are characterized by ineffective hematopoiesis and increased incidence of developing acute myeloid leukemia (AML). The mechanisms of MDS to AML transformation are poorly understood, which is partially due to the scarcity of leukemia transformation mouse models. Recently, we established a mDia1/miR146a double knockout (DKO) mouse model mimicking human del(5q) MDS. DKO mice present with pancytopenia with aging due to myeloid suppressive cell (MDSC) expansion and over-secretion of pro-inflammatory cytokines including TNF-a and interlukine-6 (IL-6). In the current study, we found that most of the DKO mice underwent leukemic transformation at 12-14 months of age. The bone marrow of these mice was largely replaced by c-Kit+ blasts in a background of fibrosis. Flow cytometry analysis and in vitro colony formation assay demonstrated that hematopoietic stem progenitor cells (HSPCs) in DKO bone marrow were dramatically declined. The leukemic DKO mice had elevated white blood cell counts and circulating blasts, which contributes to the myeloid cell infiltration in non-hematopoietic organs including liver and lung. Moreover, the splenocytes from DKO old mice efficiently reconstitute the hematopoiesis, but led to a 100% disease occurrence with rapid lethality in gramma irradiated recipient mice, suggesting the leukemic stem cells enriched in DKO spleen were transplantable. Given the significant roles of the inflammatory cytokines in the pathogenesis of the DKO mice, we crossed DKO mice with IL-6 knockout mice and generated mDia1/miR-146a/IL-6 triple knockout (TKO) mice. Strikingly, the TKO mice showed dramatic rescue of the leukemic transformation of the DKO mice in that all the aforementioned leukemic phenotypes were abolished. In addition, IL-6 deficiency normalized the cell comparts and prevented leukemic transplantation ability in TKO spleen. Single cell RNA sequencing analyses indicated that DKO leukemic mice had increased monocytic blast population with upregulation of Fn1, Csf1r, and Lgals1, that was completely diminished with IL-6 knockout. Through a multiplex ELISA, we found IL-6 deficiency attenuated the levels of multiple inflammatory cytokines in TKO serum. In summary, we report a mouse model with MDS leukemic transformation during aging, which could be reverted with the depletion of IL-6. Our data indicate that IL-6 could be a potential target in high risk MDS. Disclosures No relevant conflicts of interest to declare.

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Next Generation RNA Sequencing of Acute Promyelocytic Leukemia (APL) Identifies Novel Long Non Coding RNAs Including New Variants of MIR181A1HG That Are Differentially Expressed during Myeloid Differentiation

Blood ◽

10.1182/blood.v124.21.1031.1031 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1031-1031

Author(s):

Frederic Lammer ◽

Marion Klaumuenzer ◽

Maximilian Mossner ◽

Johann Christoph Jann ◽

Anna Hecht ◽

...

Keyword(s):

Bone Marrow ◽

Rna Sequencing ◽

Expression Analysis ◽

Myeloid Differentiation ◽

In Vitro Differentiation ◽

Hematopoietic Stem ◽

Genomic Deletion ◽

Healthy Donors ◽

Cd34 Cells

Abstract Introduction: Recently we identified a recurrent acquired genomic deletion on chromosome 1q as a potential new marker in approximately 14% of APL patients predicting a significantly increased risk of relapse (Nowak D et al., Genes Chromosomes and Cancer 2012). The deleted region contains the coding sequences for the microRNAs hsa-mir-181a1 and hsa-mir-181b1, which have been implicated as prognostic factors in Acute Myeloid Leukemia (AML) and a corresponding host gene (MIR181A1HG). To elucidate biologic mechanisms associated with the described genomic deletion we performed targeted sequencing of the affected region and RNA sequencing of APL samples carrying the deletion versus samples not carrying the deletion with subsequent validation of novel variants of MIR181A1HG. Methods: Explorative sequencing of genomic DNA in the chromosomal subband 1q31.3, pos. 197073900-197196158 (hg18) was performed using the amplicon sequencing workflow of the Roche 454 platform sequencing 5000 bp fragments tiling a region of approximately 120 kb on n=3 APL samples. Corresponding patient samples from molecular remission were used as germline controls. Whole transcriptome sequencing of poly-A enriched RNA was performed on n=6 samples of bone marrow blasts of APL patients either carrying a deletion of the mir181a1/b1 coding region (n=3) or not carrying a deletion (n=3). RNA Sequencing was performed using the HiSeq2000 platform. Data analysis was carried out using Bowtie vers. 2.2.30, TopHat vers. 2.0.12 for alignment and mapping and the Cufflinks package vers. 2.2.1 for transcriptome assembly and expression analysis all using default settings and hg19 as reference genome. Validation of newly identified variants and differential expression of MIR181A1HG was carried out by RACE PCR and qRT-PCR on cDNA from primary leukemic blasts of APL patients (n=45), CD34+ cells from healthy donors (n=29). In vitro differentiation assays with concomitant gene expression analysis of MIR181A1HG variants were performed with CD34+ cells from healthy donors. Results: Genomic sequencing of the recurrently deleted region revealed no somatically acquired mutations in the analyzed APL samples. Differential gene expression analysis using FPKM values (Fragments Per Kilobase Of Exon Per Million Fragments Mapped) inferred from RNA sequencing data of APL samples carrying a genomic deletion of 1q31.3 versus non-deleted samples identified n=58 genes significantly downregulated in deleted samples and n=31 upregulated genes. Interestingly, among the differentially regulated genes, BAALC, a factor recently shown to be prognostically relevant in APL was significantly upregulated 13 fold in the unfavourable group of samples with 1q31.3 deletions. Furthermore, RNA sequencing revealed numerous new isoforms of known transcripts as well as novel long non-conding RNA (lncRNA) sequences. Among these were a total of 6 new transcript variants of the MIR181A1HG gene in the recurrently deleted region on chromosome 1q31.3. One novel 5600bp lncRNA covering the coding regions for the hsa-mir-181a1/b1 was 24 fold overexpressed in samples carrying the recurrent 1q31.3 deletions. Expression analysis of MIR181A1HG in blasts of APL patients, CD34+ cells, unselected bone marrow cells and granulocytes of healthy donors revealed significantly elevated levels of MIR181A1HG in APL cells as compared to healthy CD34+ cells and almost absent expression in unselected bone marrow and granulocytes. This indicated a possible role for MIR181A1HG in APL blasts and hematopoietic stem cells. Subsequent in vitro differentiation experiments of primary healthy CD34+ cells showed that MIR181A1HG is downregulated 7 fold within 14 days of cytokine induced myeloid differentiation. Furthermore, MIR181A1HG was downregulated 5 fold during ATRA induced differentiation of NB4 cells. Conclusion: RNA sequencing of APL cells demonstrated numerous novel uncharacterized lncRNAs whose expression is associated with clinical risk and which merit further investigation. Identification of novel isoforms of MIR181A1HG, which are highly expressed in APL blasts and purified CD34+ cells suggest a potential role for this lncRNA in hematopoietic stem cells and response to ATRA induced differentiation of APL cells. Disclosures No relevant conflicts of interest to declare.

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ROCK1 Functions as a Suppressor of Inflammatory Cell Migration by Regulating PTEN Phosphorylation and Stability.

Blood ◽

10.1182/blood.v114.22.240.240 ◽

2009 ◽

Vol 114 (22) ◽

pp. 240-240

Author(s):

Sasidhar Vemula ◽

Jianjian Shi ◽

Philip Hanneman ◽

Lei Wei ◽

Reuben Kapur

Keyword(s):

Bone Marrow ◽

Acute Inflammation ◽

Conflicts Of Interest ◽

Flow Cytometric Analysis ◽

Fold Increase ◽

Phagocytic Index ◽

In Vivo Model ◽

Significant Difference ◽

Rho Kinases

Abstract Abstract 240 Neutrophils and macrophages are major cellular components of the innate immune response and are recruited rapidly in large numbers to sites of infection. The small family of Rho GTPases and its downstream effectors, Rho kinases (Rho-associated, coiled-coil containing protein kinase) have been implicated in regulating various cellular functions including actin cytoskeleton organization, cell adhesion, and cell motility in non-hematopoietic cells. Rho kinases (ROCK1 and ROCK2) belong to a family of serine/threonine kinases whose role in inflammation is not known. Here we show that deficiency of ROCK1 but not ROCK2 results in increased recruitment of macrophages (3.2 fold, n=8, *p<0.01) and neutrophils (3.4 fold, n=5 *p<0.05) compared to WT controls in an in vivo model of aseptic peritonitis. In vitro, deficiency of ROCK1 in bone marrow derived macrophages shows a significant increase in haptotactic transwell migration in response to M-CSF as well as MCP-1 on fibronectin as well as an increase in migration towards the wounded area in a wound healing assay compared to controls (∼3 fold, n=3, *p<0.005). Consistently, deficiency of ROCK1 in bone marrow derived neutrophils also shows a ∼2.63 fold increase in migration in response to fMLP compared to WT bone marrow derived neutrophils (BMNs) in a chemotactic migration assay. ROCK1 deficient macrophages also demonstrate a ∼2.5 fold increase in adhesion on fibronectin (n=3, *p<0.002). The enhanced migration and adhesion in ROCK1−/− macrophages was observed in spite of comparable expression of F4/80 (WT; 85.63% vs. ROCK1−/−; 88.68%, n=4), α4β1 and α5β1 integrins (WT; 67.49% & 88.2% vs. ROCK1−/−; 71.82 % & 87.09%, n=4), while no significant difference in the phagocytosis of sheep red blood cells was observed between WT and ROCK1−/− macrophages (Phagocytic index: WT; 98% vs. ROCK1−/− 97%, n=3, p>.05). Close examination of the cytoskeleton of ROCK1 deficient macrophages using confocal microscopy revealed more F-actin content on the entire cell surface compared to wildtype controls. Consistently, flow cytometric analysis using Alexa 488-phalloidin staining revealed abundance of F-actin in ROCK1−/− macrophages compared to WT controls (WT; 46.19% vs. ROCK1−/−; 65.23%, n=3, *p<0.05). Furthermore, immunofluorescence imaging of podosomes carried out using anti-vinculin antibody revealed more pronounced and increased podosomes in ROCK1 deficient macrophages compared to WT controls (n=3, *p<0.05). Biochemical analysis of ROCK1−/− macrophages revealed that the enhanced recruitment of ROCK1 deficient macrophages and neutrophils was apparent in spite of normal expression of ROCK2 in ROCK1−/− cells and a 60% reduction in overall ROCK activity. Interestingly, although both ROCK1 and ROCK2 co-immunoprecipitate with PTEN in response to cytokine induced stimulation, only ROCK1 appeared to be essential for PTEN phosphorylation, activation and stability. In the absence of ROCK1, PTEN phosphorylation, its activity and stability were significantly impaired in spite of the presence of ROCK2 (n=3, *p<0.05). Consequently, an increase in the activation of downstream targets of PTEN including AKT, GSK-3β and cyclinD1 was observed in ROCK1 deficient macrophages relative to controls (n=3). Taken together, these studies reveal a biochemical pathway involving ROCK1 and PTEN which is involved in the recruitment of macrophages and neutrophils during acute inflammation. Thus, ROCK1 likely functions as a physiologic regulator of PTEN whose function is to repress excessive recruitment of macrophages and neutrophils during acute inflammation. Disclosures: No relevant conflicts of interest to declare.

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Engineering Biomimetic Culture Systems: Impact On Human Bone Marrow-Derived Stem Cells.

Blood ◽

10.1182/blood.v114.22.3628.3628 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3628-3628

Author(s):

Marina Prewitz ◽

Friedrich Philipp Seib ◽

Martin Bornhaeuser ◽

Carsten Werner

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Conflicts Of Interest ◽

Human Peripheral Blood ◽

Cell Lysis ◽

Published Data ◽

Differentiation Potential ◽

Significant Difference ◽

Defined Culture

Abstract Abstract 3628 Poster Board III-564 The bone marrow (BM) harbours haematopoietic stem/progenitor cells (HSCs) in anatomically distinct sites (niches) where HSCs are subjected to regulatory cues such as cytokines, cell-cell contacts and extra-cellular matrix (ECM) all of which control stem cell fate. In particular mesenchymal stromal cells (MSCs) are an integral part of the bone marrow and are known to be key regulators of the HSC niche. We have previously shown that bio-artificial scaffolds can have a significant impact on the in vitro behaviour of MSCs. Here, we are therefore focussing on the role of (native) ECM within the MSC-HSC microenvironment by building on our previous findings and published data (Seib et al.,Tissue Eng Part A., 2009 in press). Thus the aim of the current study is (a) to identify niche-specific ECM components and (b) the use of such ECMs for in vitro culture of BM-derived stem cells. To mimic the natural ECM composition of the BM, different ECM types were generated from BM-derived cells using (a) Dexter cultures, (b) standard MSC cultures, (c) MSCs subjected to osteogenic differentiation. After 10 days of culture those MSC-derived ECMs were decellularised using 0.5% Triton-X and 20mM NH4OH leaving only the ECM behind (verified by scanning electron microscopy). Those ECMs were used as a substrate for a second culture of MSCs, which were analysed for their proliferation and differentiation potential. Cell-free ECM from standard MSC cultures improved MSC proliferation compared to cells grown on regular tissue culture plastic (TCP) over the period of 8 days. Most notably, all cell-free ECM preparations lead to a significant difference in the cytoskeletal arrangement of MSCs during the first 2 days of culture compared to TCP controls. Cultivation of MSCs on native ECM provided a guiding structure for those cells to grow into, and helped to maintain an elongated cell shape compared to substantial cell spreading on TCP (roundness 0.2 versus 0.5 and cell area of 2.2 versus 8.2mm2, respectively, p<0.001, n=60. A factor of 1 was set to equate to a perfect circle). Next, we investigate if native ECM could either directly improve HSC cultures or maximise MSC feeder characteristics. For the latter set of studies MSCs were initially cultured for 7 days on cell-free ECM (from standard MSC cultures) and subsequently co-cultured with human peripheral blood CD34+ HSCs in serum free medium supplemented with cytokines (Tpo, Flt3, and SCF at 10ng/ml). Following a 14 day culture period up to 3.5-fold more CD34+ cells were present in ECM co-cultures compared to TCP co-cultures that was accompanied with an overall expansion of CD45+ cells of 109-fold versus 35-fold, respectively. Our data suggest that ECM preparations derived from MSCs might be useful to accomplish better expansion of HSCs under defined culture conditions. In addition, this system permits the identification of bimolecular key components that can be utilized in the future design of simple and robust carrier systems for improved HSC maintenance in vitro. Figure HSC-MSC co-culture on preformed ECM substrates. (A) MSC-derived ECM (from standard MSC culture) following cell lysis (complete absence of cells). (B) Growth of a new set of MSCs on ECM substrates as shown in (A). (C) HSC-MSC co-culture on ECM substrates. Scale bars at 2μm. Arrow heads point out ECM structures. Figure HSC-MSC co-culture on preformed ECM substrates. (A) MSC-derived ECM (from standard MSC culture) following cell lysis (complete absence of cells). (B) Growth of a new set of MSCs on ECM substrates as shown in (A). (C) HSC-MSC co-culture on ECM substrates. Scale bars at 2μm. Arrow heads point out ECM structures. Disclosures: No relevant conflicts of interest to declare.

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Leukemia-Induced Alterations of Bone Marrow Microenvironment Contribute to Leukemogenesis.

Blood ◽

10.1182/blood.v116.21.2597.2597 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2597-2597

Author(s):

Jae-Seung Shim ◽

Myungshin Kim ◽

Jong Wook Lee ◽

Il-Hoan Oh

Keyword(s):

Conflicts Of Interest ◽

Growth Arrest ◽

Normal Growth ◽

Qualitative Change ◽

Myelogenous Leukemia ◽

Cd34 Cells ◽

Significant Difference ◽

Acute Myelogenous ◽

The Impact

Abstract Abstract 2597 The impact of microenvironment on the regulation of normal hematopoietic process is being unveiled, but their role during leukemogenesis have been poorly understood. In this study, to characterize the leukemic microenvironment, we have analyzed mesenchymal stromal cells (MSC) of bone marrows from 55 cases of acute myelogenous leukemia (AML), and 17 of AML in the remission. When the colonogenic activity of MSCs were compared, 43% of AML-derived BM exhibited defect in colony (CFU-F) formation, where no colony formation or premature growth arrest of colonies were observed, whereas only 11% of normal BM exhibited growth arrest of colonies. In the AML subtypes, M3 type (FAB classification) exhibited most profound loss of CFU-Fs, where none of them (n=9) exhibited normal growth of colonies. In addition, numbers of colony (CFU-F) in AML was significantly lower than normal BM (52 vs. 155 per each ml of BM, respectively for AML and normal, p<0.05). In contrast, BMs of AML in remission did not exhibit significant difference in the number of CFU-F compared to numbers of normal BM (88 vs. 71.4 per 5×106 MNCs, respectively for normal and remission), indicating that the quantitative loss of CFU-F is correlated to disease activity of AML. We next examined the qualitative changes of MSCs in AML, i.e., 83% of MSCs in AML (5/6) exhibited poor osteogenic differentiation, and all examined AML MSCs (6/6) exhibited lower adipogenic differentiaton compared to normal MSCs. During in-vitro culture, MSCs from AML showed accelerated loss of colonogenic activity during passage cultures compared to normal MSCs and lower intensity levels of CD146 in the cell surface. Moreover, MSCs from AML showed significantly higher levels of senescence-associated beta-galactosidase without changes in telomere length, indicating that the MSC has undergone qualitative change during leukemogenesis. When co-cultured with umbilical cord blood-derived CD34+ cells, AML-derived MSCs inhibited proliferation of CD34+ cells and caused significantly lower levels of hematopoietic cell expansion compared to the levels from co-culture with normal BM-derived MSCs or stroma-free cultures, indicating that leukemic MSCs should contribute to the loss of normal hematopoietic cells in leukemia. Taken together, our study shows that microenvironment of BM undergoes quantitative and qualitative alteration during leukemogenesis and that such leukemic microenvironment contributes to the pathology of leukemia. Disclosures: No relevant conflicts of interest to declare.

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Dose-Adjusted Granulocyte Colony-Stimulating Factor Plus Dexamethasone Achieves More CD34+ Cell Mobilization and Earlier Engraftment in Haploidentical Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood-2019-126632 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1966-1966

Author(s):

Chenglong Li ◽

Xi Yang ◽

Jingying Dai ◽

Ningning Tang ◽

Hong Zheng ◽

...

Keyword(s):

Bone Marrow ◽

Stem Cell ◽

Hematopoietic Stem Cell Transplantation ◽

Stem Cell Transplantation ◽

Peripheral Blood ◽

Hematopoietic Stem ◽

Healthy Donors ◽

Cd34 Cells ◽

Significant Difference ◽

Cell Mobilization

Introduction: Previous studies have showed that higher doses of CD34+ cell were associated with more rapid neutrophil and platelet engraftment, lower probabilities of graft rejection, as well as reduced transplant-related mortality. The aim of this study was to investigate the effects of G-CSF (Filgrastim) plus dexamethasone in CD34+ cell mobilization and engraftment in T-cell replete haploidentical hematopoietic stem cell transplantation(HHSCT) which was based on G-CSF-primed bone marrow and peripheral blood graft. Methods: A total of 79 healthy donors, who underwent bone marrow (BM) harvest and peripheral blood Stem Cells (PBSCs) collection between January 2015 and June 2019, were investigated. In G-CSF group, G-CSF was administered subcutaneously at a dose of 5μg/kg once a day from 1st to 5th day, while BM and PBSC were harvested on the 4th day and 5th day, respectively. In Dose-Adjusted G-CSF+Dex group, G-CSF was administered subcutaneously at a dose of 5μg/kg once a day on the 1st and 2nd day, then twice a day from the 3rd to 5th day; 5mg dexamethasone was injected intravenously before BM collection on the 4th day and before PBSC apheresis on the 5th day, respectively. All 79 recipients with hematological malignancies underwent HHSCT based on modification of BU/CY (busulfan/cyclophosphamide) and Anti-human T Lymphocyte Rabbit Immunoglobulin (ATG-F). All recipients received cyclosporine A, mycophenolate mofetil, and short-term cyclophosphamide as GVHD prophylaxis. Results: There were no significantly statistical differences between these two groups on characteristics of both recipients and donors. In Dose-Adjusted-G-CSF+Dex group, more mono nuclear cells (MNCs) were collected from BM and PB in comparison to the cells collected in the G-CSF group (p<0.001). There was a significant difference between the two groups on CD34+ cell counts from PB (p=0.002), which led to a significant difference on CD34+ cells in mixture allografts (p=0.04). In DA-G-CSF + Dex group, more CD34+ cells achieved earlier neutrophil (p=0.001) and platelet (p<0.001) engraftment compared with G-CSF group. Conclusion: Compared to G-CSF alone, dose-adjusted G-CSF plus dexamethasone on healthy donors can lead to more collection of MNCs and CD34+ cells in mixture allografts, which achieves earlier neutrophil and platelet engraftment. Disclosures Zheng: Pfizer: Research Funding.

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