scholarly journals Diabetes Induces a Transcriptional Signature in Bone Marrow–Derived CD34+ Hematopoietic Stem Cells Predictive of Their Progeny Dysfunction

2021 ◽  
Vol 22 (3) ◽  
pp. 1423
Author(s):  
Yuri D’Alessandra ◽  
Mattia Chiesa ◽  
Vera Vigorelli ◽  
Veronica Ricci ◽  
Erica Rurali ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Coronary Bypass ◽  
Enrichment Analysis ◽  
Gene Set Enrichment Analysis ◽  
P Value ◽  
Peptidase Activity ◽  
Biological Processes ◽  
Hematopoietic Stem ◽  
The Impact

Hematopoietic stem/progenitor cells (HSPCs) participate in cardiovascular (CV) homeostasis and generate different types of blood cells including lymphoid and myeloid cells. Diabetes mellitus (DM) is characterized by chronic increase of pro-inflammatory mediators, which play an important role in the development of CV disease, and increased susceptibility to infections. Here, we aimed to evaluate the impact of DM on the transcriptional profile of HSPCs derived from bone marrow (BM). Total RNA of BM-derived CD34+ stem cells purified from sternal biopsies of patients undergoing coronary bypass surgery with or without DM (CAD and CAD-DM patients) was sequenced. The results evidenced 10566 expressed genes whose 79% were protein-coding genes, and 21% non-coding RNA. We identified 139 differentially expressed genes (p-value < 0.05 and |log2 FC| > 0.5) between the two comparing groups of CAD and CAD-DM patients. Gene Set Enrichment Analysis (GSEA), based on Gene Ontology biological processes (GO-BP) terms, led to the identification of fourteen overrepresented biological categories in CAD-DM samples. Most of the biological processes were related to lymphocyte activation, chemotaxis, peptidase activity, and innate immune response. Specifically, HSPCs from CAD-DM patients displayed reduced expression of genes coding for proteins regulating antibacterial and antivirus host defense as well as macrophage differentiation and lymphocyte emigration, proliferation, and differentiation. However, within the same biological processes, a consistent number of inflammatory genes coding for chemokines and cytokines were up-regulated. Our findings suggest that DM induces transcriptional alterations in HSPCs, which are potentially responsible of progeny dysfunction.

The Impact of Age and Gender on Hematopoietic Stem Cells and Immune Contexture of the Bone Marrow Microenvironment

2020 ◽  
pp. 1-6
Author(s):  
Rebar N. Mohammed
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Immune Cells ◽  
Absolute Number ◽  
Cell Number ◽  
Hematopoietic Stem ◽  
The Absolute ◽  
And Gender ◽  
The Impact

Hematopoietic stem cells (HSCs) are a rare population of cells that reside mainly in the bone marrow and are capable of generating and fulfilling the entire hematopoietic system upon differentiation. Thirty-six healthy donors, attending the HSCT center to donate their bone marrow, were categorized according to their age into child (0–12 years), adolescence (13–18 years), and adult (19–59 years) groups, and gender into male and female groups. Then, the absolute number of HSCs and mature immune cells in their harvested bone marrow was investigated. Here, we report that the absolute cell number can vary considerably based on the age of the healthy donor, and the number of both HSCs and immune cells declines with advancing age. The gender of the donor (male or female) did not have any impact on the number of the HSCs and immune cells in the bone marrow. In conclusion, since the number of HSCs plays a pivotal role in the clinical outcome of allogeneic HSC transplantations, identifying a younger donor regardless the gender is critical.

scholarly journals Hematopoietic Stem Cells Are Endowed with Erythroid Signature in Beta-Thalassemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-31
Author(s):  
Maria Rosa Lidonnici ◽  
Giulia Chianella ◽  
Francesca Tiboni ◽  
Matteo Barcella ◽  
Ivan Merelli ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Gene Set Enrichment Analysis ◽  
Lineage Commitment ◽  
Erythroid Cell ◽  
Beta Thalassemia ◽  
Hematopoietic Stem ◽  
Multipotent Progenitors

Background Beta-thalassemia (Bthal) is a genetic disorder due to mutations in the ß-globin gene, leading to a reduced or absent production of HbA, which interferes with erythroid cell maturation and limits normal red cell production. Patients are affected by severe anemia, hepatosplenomegaly, and skeletal abnormalities due to rapid expansion of the erythroid compartment in bone marrow (BM) caused by ineffective erythropoiesis. In a classical view of hematopoiesis, the blood cell lineages arise via a hierarchical scheme starting with multipotent stem cells that become increasingly restricted in their differentiation potential through oligopotent and then unipotent progenitors. In human, novel purification strategies based on differential expression of CD49f and CD90 enrich for long-term (49f+) and short-term (49f−) repopulating hematopoietic stem cells (HSCs), with distinct cell cycle properties, but similar myeloid (My) and lymphoid (Ly) potential. In this view, it has been proposed that erythroid (Ery) and megakaryocytic (Mk) fates branch off directly from CD90-/49f− multipotent progenitors (MPPs). Recently, a new study suggested that separation between multipotent (Ery/My/Ly) long-term repopulating cells (Subset1, defined as CLEC9AhighCD34low) and cells with only My/Ly and no Ery potential (Subset2, defined as CLEC9AlowCD34high)occurs within the phenotypic HSC/MPP and CD49f+ HSCs compartment. Aims A general perturbed and stress condition is present in the thalassemic BM microenvironment. Since its impact on the hematopoietic cell subpopulations is mostly unknown, we will investigate which model of hematopoiesis/erythropoiesis occurs in Bthal. Moreover, since Beta-Thalassemia is an erythropoietic disorder, it could be considered as a disease model to study the 'erythroid branching' in the hematopoietic hierarchy. Methods We defined by immunophenotype and functional analysis the lineage commitment of most primitive HSC/MPP cells in patients affected by this pathology compared to healthy donors (HDs). Furthermore, in order to delineate the transcriptional networks governing hematopoiesis in Beta-thalassemia, RNAseq analysis was performed on sorted hematopoietic subpopulations from BM of Bthal patients and HDs. By droplet digital PCR on RNA purified from mesenchymal stromal cells of Bthal patients, we evaluated the expression levels of some niche factors involved in the regulation of hematopoiesis and erythropoiesis. Moreover, the protein levels in the BM plasma were analyzed by performing ELISA. Results Differences in the primitive compartment were observed with an increased proportion of multipotent progenitors in Bthal patients compared to HDs. The Subset1 compartment is actually endowed with an enhanced Ery potential. Focusing on progenitors (CD34+ CD38+) and using a new sorting scheme that efficiently resolved My, Ery, and Mk lineage fates, we quantified the new My (CD71-BAH1-/+) and Ery (CD71+ BAH1-/+) subsets and found a reduction of Ery subset in Bthal samples. We can hypothesize that the erythroid-enriched subsets are more prone to differentiate quickly due to the higher sensitivity to Epo stimuli or other bone marrow niche signals. Gene set enrichment analysis, perfomed on RNAseq data, showed that Bthal HSC/MPP presented negative enrichment of several pathways related to stemness and quiescence. Cellular processes involved in erythropoiesis were found altered in Bthal HSC. Moreover, some master erythroid transcription factors involved were overrepresented in Bthal across the hematopoietic cascade. We identified the niche factors which affect molecular pathways and the lineage commitment of Bthal HSCs. Summary/Conclusions Overall, these data indicate that Bthal HSCs are more cycling cells which egress from the quiescent state probably towards an erythroid differentiation, probably in response to a chronic BM stimulation. On the other hand,some evidences support our hypothesis of an 'erythroid branching' already present in the HSC pool, exacerbated by the pathophysiology of the disease. Disclosures No relevant conflicts of interest to declare.

scholarly journals PDGFB-expressing mesenchymal stem cells improve human hematopoietic stem cell engraftment in immunodeficient mice

2019 ◽  
Vol 55 (6) ◽  
pp. 1029-1040 ◽  
Author(s):  
Xiuxiu Yin ◽  
Linping Hu ◽  
Yawen Zhang ◽  
Caiying Zhu ◽  
Hui Cheng ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Human Mesenchymal Stem Cells ◽  
Enrichment Analysis ◽  
Gene Set Enrichment Analysis ◽  
Hematopoietic Stem ◽  
Immunodeficient Mice ◽  
Bm Niche

AbstractThe bone marrow (BM) niche regulates multiple hematopoietic stem cell (HSC) processes. Clinical treatment for hematological malignancies by HSC transplantation often requires preconditioning via total body irradiation, which severely and irreversibly impairs the BM niche and HSC regeneration. Novel strategies are needed to enhance HSC regeneration in irradiated BM. We compared the effects of EGF, FGF2, and PDGFB on HSC regeneration using human mesenchymal stem cells (MSCs) that were transduced with these factors via lentiviral vectors. Among the above niche factors tested, MSCs transduced with PDGFB (PDGFB-MSCs) most significantly improved human HSC engraftment in immunodeficient mice. PDGFB-MSC-treated BM enhanced transplanted human HSC self-renewal in secondary transplantations more efficiently than GFP-transduced MSCs (GFP-MSCs). Gene set enrichment analysis showed increased antiapoptotic signaling in PDGFB-MSCs compared with GFP-MSCs. PDGFB-MSCs exhibited enhanced survival and expansion after transplantation, resulting in an enlarged humanized niche cell pool that provide a better humanized microenvironment to facilitate superior engraftment and proliferation of human hematopoietic cells. Our studies demonstrate the efficacy of PDGFB-MSCs in supporting human HSC engraftment.

G-CSF Treatment Induces Toll-Like Receptor Signaling and Regulates Hematopoietic Stem Cell Function

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1181-1181 ◽  
Author(s):  
Laura G. Schuettpelz ◽  
Joshua N. Borgerding ◽  
Priya Gopalan ◽  
Matt Christopher ◽  
Molly Romine ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cell Function ◽  
Conflicts Of Interest ◽  
Bone Marrow Failure ◽  
Intestinal Flora ◽  
Enrichment Analysis ◽  
Gene Set Enrichment Analysis ◽  
Tlr Signaling ◽  
Hematopoietic Stem

Abstract Recent studies demonstrate that inflammatory signals regulate hematopoietic stem cells (HSCs). Granulocyte-colony stimulating factor (G-CSF) is often induced with infection and plays a key role in the stress granulopoiesis response. However, its effects on HSCs are unclear. Herein, we show that treatment with G-CSF induces expansion and increased quiescence of phenotypic HSCs, but causes a marked, cell-autonomous HSC repopulating defect. RNA profiling and flow cytometry studies of HSCs from G-CSF treated mice show that multiple toll- like receptors (TLRs) are upregulated in HSCs upon G-CSF treatment, and gene set enrichment analysis shows enhancement of TLR signaling in G-CSF-treated HSCs. G-CSF-induced expansion of phenotypic HSCs is reduced in mice lacking the TLR signaling adaptors MyD88 or Trif, and the induction of quiescence is abrogated in mice lacking these adaptors. Furthermore, loss of TLR4 mitigates the G-CSF-mediated HSC repopulating defect. Interestingly, baseline HSC function is also dependent on TLR signaling. We show that HSC long-term repopulating activity is enhanced in Tlr4-/- and MyD88-/- mice, but not Trif-/- mice. One potential source of TLR ligands affecting HSC function in the bone marrow is the gut microbiota. Indeed, we show that in mice treated with antibiotics to suppress intestinal flora, G-CSF induced HSC quiescence and hematopoietic progenitor mobilization are attenuated. Moreover, in germ free mice, HSC long-term repopulating activity is enhanced. Collectively these data suggest that low level TLR agonist production by commensal flora contributes to the regulation of HSC function and that G-CSF negatively regulates HSCs, in part, by enhancing TLR signaling. Our finding of enhanced TLR signaling upon G-CSF treatment, and the mitigation of G-CSF’s effects in mice deficient for TLR signaling or commensal organisms, suggest that TLR antagonists and/or agonists may ultimately be used clinically to enhance engraftment following bone marrow transplantation or applied toward the treatment of patients with bone marrow failure. Disclosures: No relevant conflicts of interest to declare.

Impact of Infusion Rate on the Early Engraftment Following Allogeneic Intra Bone Marrow Infusion of Hematopoietic Stem Cells in a Canine DLA-Identical Reduced Intensity Transplantation Model

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 5406-5406
Author(s):  
Stephanie Schaefer ◽  
Juliane Werner ◽  
Sandra Lange ◽  
Katja Neumann ◽  
Christoph Machka ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Infusion Rate ◽  
Conflicts Of Interest ◽  
Conditioning Regimen ◽  
Hematopoietic Stem ◽  
Time Points ◽  
The Impact ◽  
Reduced Intensity

Abstract Introduction: Direct intra bonemarrow (IBM) infusion of hematopoietic stem cells (HSC) is assumed to improve the homing efficiency and to accelerate the early engraftment in comparison to the conventional intravenous application of HSC. Especially for transplantation of low cell numbers i.e. "weak grafts" that is generally associated with delayed engraftment. The direct infusion of HSC in close proximity to the HSC niche by intra bone marrow transplantation (IBMT) might be a promising way. Whether the HSC infusion rate might influence the homing process and therefore the outcome after IBMT is so far unknown. Aims: Herein, we analyzed in a canine DLA-identical littermate model the impact of different graft infusion rates on the hematopoietic recovery as well as on the engraftment kinetics after IBMT following reduced intensity conditioning. Methods: Recipient dogs received IBMT following a 4.5 Gy total body irradiation (TBI). From day (d) -1 until d+35 Cyclosporin A (15mg/kg) was administered orally twice a day as immunosuppression. For IBM transfusion the graft volume was reduced by buffy coat centrifugation and dogs obtained 2x25 ml simultaneously into the humerus and femur. The infusion rate of the graft was 25ml/10 min in group 1 (IBM10, n = 8) and 25 ml/60 min in group 2 (IBM60, n = 7). A 28 day follow-up is currently available for twelve dogs (IBM10 n = 7; IBM60 n = 5). The development of the peripheral blood mononuclear cell (PBMC) and granulocyte chimerism was tested weekly. Blood count, kidney and liver enzymes were monitored routinely. Results: All animals engrafted. One dog of the IBM10 group died at d+15 (infection) and was therefore not included into analysis. The median number of infused total nucleated cells were in IBM10 4.1*108/kg (range 2.3-6.0*108/kg) and in IBM60 3.2*108/kg (range 1.8-4.4*108/kg; p=0.4). The infused CD34+ numbers were median 3.2*106/kg (range: 1.2-10.0*106/kg; IBM10) and 3.6*106/kg (range: 1.5-6.8*106/kg; IBM60; p=0.7). Time of leukocyte recovery was median d+11 after IBMT in both groups (range: d+4 to d+11, IBM10; d+8 to d+14, IBM60; p= 0.5). Median leukocytes nadirs amounted to 0.2*109/l for IBM10 and 0.3*109/l for IBM60 (p= 0.08). The median duration of leukopenia (<1*109/l) were similar (6d, range: 4-11d, IBM10; 3-9d, IBM60) (p= 0.6). Median platelet nadir was 0*109/l for both cohorts (range: 0.0-7.0*109/l, IBM10; 0.0-1.0*109/l, IBM60). The period of thrombocytopenia (≤20.0*109/l) was significantly prolonged in the IBM60 group (median 10d, range) compared to 5d (range: 3-12d) in the IBM10 group (p=0.05). Donor PBMC chimerisms at d+7, d+14 and d+28 were median 22% (range: 8-34%), 50% (range: 29-53%) and 67% (range: 47-73%) in IBM10. The results of PBMC chimerism for IBM60 were 11% (range: 5-34%), 42% (range: 20-42%) and 59% (range: 44-66%) at these time points (p = n.s.). Donor granulocyte chimerisms of median 33% (range: 11-83%), 100% (range: 58-100%) and 100% (range: 82-100%) were detected at d+7, d+14 and d+28 after HSCT in IBM10, respectively. The granulocyte chimerism in IBM60 amounted to 34% (range: 3-87%), 96% (range: 94-100%) and 98% (range: 96-100%) at the above mentioned time points p=n.s. for all time points). Conclusion: Our data suggest that early granulocyte and PBMC engraftment is not influenced by modification of the HSC infusion rate. However, the period of thrombocytopenia seems to be prolonged following a 60 minutes application. Therefore, longer infusion times in an IBMT setting seem not to be beneficial following toxicity reduced conditioning regimen. Disclosures No relevant conflicts of interest to declare.

Characterization of Hematopoietic and Non-Hematopoietic Stem/Progenitor Cells in Freshly Isolated Adult Human Bone Marrow Using an 8-Color Flow Cytometric Assay.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4045-4045
Author(s):  
Ferda Tekinturhan ◽  
Ludovic Zimmerlin ◽  
Vera S. Donnenberg ◽  
Melanie E. Pfeifer ◽  
Darlene A. Monlish ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Progenitor Cell ◽  
P Value ◽  
Hematopoietic Stem ◽  
Adult Human

Abstract Bone marrow (BM) contains hematopoietic stem cells (HSCs), which can give rise to all mature blood cells and marrow stromal cells as well. Recently, it has been shown that non-hematopoietic stem/progenitor cells which can differentiate into non-hematopoietic tissues also reside in the BM. Although culture expanded cells have been studied in great detail, little is known about the phenotype and quantity of these cells in freshly harvested adult human BM. The aim of this study is to isolate and characterize hematopoietic and non-hematopoietic stem/progenitor cells in adult human BM by comparing two different isolation techniques and their effects on the yield of hematopoietic, mesenchymal and endothelial stem/progenitor cell populations. BM samples were collected mechanically from isolated rib specimens obtained during lung resection (n=10), or from BM aspirates harvested from the humerus of orthopedic patients (n=17). BM mononuclear cells were purified on a Ficoll/Hypaque density gradient and stained simultaneously using CD105 FITC, CD73 PE, CD34 ECD, CD90 PE.Cy5, CD117 PE.Cy7, CD133 APC, CD45 APC.Cy7 and DAPI as a marker of nucleated cells. 2–15 million cells per sample were acquired on a Dako CyAn cytometer and the data were analyzed offline using prototype analytical software (Venturi, Applied Cytometry Systems). The significant difference in the percentage of the CD45 − singlets (non-hematopoietic cells) between BM aspirates and rib-derived samples indicates hemodilution in the bone marrow aspirates. Although we have observed a slight difference in the mean of hematopoietic stem cell content between samples, it was not statistically significant. According to our results, the quantity of mesenchymal stem cells was higher in rib-derived BM than BM aspirates (p value=0.028). The expression of some stem/progenitor cell markers, such as CD90 (Thy-1), CD117 (c-Kit) and CD133 remained similar for all cell types. Our results are shown in the table below. Surface Antigens RibBM (n=10)¥ BMA (n=17)¥ p Value % % Total Cells CD45- of nucleated cells 15.3 ± 7.9 5.7 ± 5.2 0.004 CD34+ Hematopoietic Stem Cells (HSCs)* CD34 of CD45+ 1.7 ± 1.48 2.6 ± 2.0 0.883 CD117 74.6 ± 31.3 53.3 ± 18.8 0.073 CD90 60.3 ± 44.5 35.9 ± 36.5 0.134 CD133 70.3 ± 31.8 62.3 ± 21.4 0.443 Endothelial Progenitor Cells (EPCs)* EPCs of nucleated cells 0.05 ± 0.03 0.12 ± 0.2 0.323 CD117 81.3 ± 29.8 78.1 ± 20.2 0.746 CD90 66.7 ± 39.7 53.7 ± 31.4 0.356 CD133 45.9 ± 32.7 33.9 ± 22.0 0.265 Mesenchymal Stem Cells (MSCs)* MSCs of nucleated cells 0.086 ± 0.14 0.008 ± 0.01 0.028 CD117 60.2 ± 36.8 49.8 ± 34.3 0.471 CD90 66.0 ± 27.7 65.7 ± 29.1 0.981 CD133 37.8 ± 27.4 39.9 ± 28.9 0.857 RibBM: Rib-derived BM, BMA: Bone Marrow Aspirate ¥Data are given as mean ± SD. *CD90, CD117 and CD133 expressions are shown for each stem/progenitor fraction: Hematopoietic stem cells (CD34 + CD45 + and light scatter properties according to the ISHAGE protocol), endothelial progenitor cells (CD34bright CD45 − CD105 +) and mesenchymal stem cells (CD34 − CD45 − CD73 + CD105 +).

Ott1(Rbm15)-Deficient Hematopoietic Stem Cells Are Unable to Maintain Quiescence During Replicative Stress and Display Features of Premature Aging,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3433-3433
Author(s):  
Nan Xiao ◽  
Kaushal Jani ◽  
Jonathan L Jesneck ◽  
Glen D Raffel
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Bone Marrow ◽  
Steady State ◽  
Hematopoietic Stem Cells ◽  
Bone Marrow Failure ◽  
Gene Set Enrichment Analysis ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Replicative Stress

Abstract Abstract 3433 With age, hematopoietic stem cells (HSCs) have numerical expansion, skewing towards myeloid development, loss of lymphoid potential, an underlying pro-inflammatory state and loss of self-renewal potential thus severely limiting responses to hematopoietic stress, ultimately leading to bone marrow failure. The mechanisms and pathways responsible for these changes in aged HSCs are incompletely understood. Using a conditional allele of Ott1, a gene originally isolated as the 5' fusion partner in t(1;22) acute megakaryocytic leukemia, we previously found a global regulatory role for the gene in hematopoiesis. Deletion of Ott1 in adult mice utilizing Mx1-cre recapitulated certain aspects of aging hematopoiesis including increased Lin−Sca1+c-Kit+ (LSK) population, myeloid expansion and decreased lymphopoiesis. The LSK compartment was further characterized using SLAM and CD34/Flk2 markers and demonstrated normal levels of LT-HSCs and increased ST-HSCs. Despite sufficient LT-HSC numbers, Ott1-deleted bone marrow was unable to competitively or non-competitively repopulate irradiated recipients. To exclude a homing or engraftment effect, Ott1flox/null Mx1-cre bone marrow was transplanted with competitor then excised post-engraftment. The rapid loss of the Ott1-deficient graft demonstrated Ott1 is required for maintenance under competitive stress. In contrast, primary mice undergoing Ott1 excision lived a normal lifespan and were able to maintain sufficient hematopoiesis although with a partial reduction in bone marrow clonagenicity showing loss of Ott1 is not limiting under steady state conditions. To test the HSC requirement for Ott1 under replicative stress, Ott1 knockout mice were challenged with 5-fluorouracil (5-FU). Ott1-deleted mice treated with 5-FU displayed delayed peripheral blood neutrophil recovery and showed accelerated bone marrow failure. Cell cycle analysis of steady state Ott1 knockout HSCs showed a similar profile to wild type controls, however, after 5-FU treatment, the G0 fraction was dramatically reduced. The G0 fraction is associated with the quiescent, self-renewing HSC population, therefore, Ott1 is required for maintaining HSC quiescence during replicative stress but not steady state hematopoiesis. To more specifically assess whether the functional hematopoietic changes seen after loss of Ott1 were accompanied by alterations in known aging-associated pathways, Gene Set Enrichment Analysis comparing Ott1-deleted HSCs in steady state to aged HSCs was performed and showed a highly enriched gene expression signature (NES 2.02 p<0.0001). Physiologic sequelae of HSC aging were observed after Ott1 excision including activation of NFκβ, elevation of reactive oxygen species (ROS), increase in DNA damage (γH2A.X levels) and activation of p38Mapk. Although ROS was elevated under steady state conditions, neither apoptosis, senescence or proliferation was significantly different from wild type control HSCs. Furthermore, anti-oxidant treatment with N-acetyl-cysteine was unable to rescue the HSC maintenance defect of the Ott1 knockout, signifying additional requirements in HSCs for Ott1 beyond regulation of ROS. An observed increase of mitochondrial mass in Ott1-deleted HSCs suggests an upstream function for Ott1 in metabolic control, potentially contributing to ROS generation or degradation. In summary, we have demonstrated an essential role for Ott1 in maintaining HSC quiescence during replicative stress and shown loss of Ott1 leads to the acquisition of key gene expression patterns and pathophysiologic changes associated with aging. These data suggest Ott1 functions in part to oppose specific consequences of aging in the hematopoietic compartment. Ott1 and Ott1-dependent pathways therefore represent a potential therapeutic target to prevent the morbidity and mortality arising from age-related defects in hematopoiesis. Disclosures: No relevant conflicts of interest to declare.

scholarly journals CSF3-Receptor Downregulation in Bone Marrow contributes to Ineffectiveness of GCSF in Advanced Liver Cirrhosis

2021 ◽  
Author(s):  
Chhagan Bihari ◽  
Sukriti Baweja ◽  
Deepika Lal ◽  
Seggere Murlikrishna Shasthry ◽  
Preeti Negi ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Enrichment Analysis ◽  
Gene Set Enrichment Analysis ◽  
Severe Neutropenia ◽  
Inadequate Response ◽  
Variable Response ◽  
Inhibitory Protein ◽  
Hematopoietic Stem ◽  
Qrt Pcr ◽  
Advanced Cirrhosis

Abstract Introduction: Cirrhosis patients exhibit cytopenia and variable response to GCSF, with benefits in early cirrhosis. GCSF acts through the CSF3-receptor (CSF3R), and changes in CSF3R can affect the response. We investigated the possible mechanism for the lack of efficacy of GCSF in advanced cirrhosisMethodsCirrhotic patients (n = 127) and controls (n = 26) who underwent clinically indicated bone marrow (BM) examination were studied. BMs were assessed for RNA sequencing, qRT-PCR, and immunohistochemistry (IHC) for CSF3R and associated genes. Circulating GCSF, CSF3R, and carcinoembryonic antigen cell adhesion molecule-1 (CEACAM1) were measured. BM hematopoietic precursor cells and their alterations were examined by flow cytometry. The findings were validated, where the GCSF was administered as for liver regeneration (n = 22) and severe neutropenia (n = 15)ResultsThe mean age was 48.6 ± 13.4 years, 80.3% males. Gene set enrichment analysis showed lowered CSF3R in Child's C compared to A, confirmed by qRT-PCR and IHC. Circulatory CSF3R was also reduced in advanced cirrhosis. CSF3R decline was related to decrease hematopoietic stem cells (HSCs) and downregulation of CSF3R in remaining HSCs. CSF3R inhibitory protein CEACAM1 caused CSF3R downregulation. CEACAM-1, in turn, positively correlated with the increased lysosomal expression in HSCs. Peripheral blood-CSF3R was lesser in those cases who developed an infection Baseline CSF3R was also lower in G-CSF non-responders.ConclusionsCSF3R is downregulated in patients with advanced cirrhosis, and it could be the underlying cause of the inadequate response to GCSF.

Interferon-Gamma Impairs the Self-Renewal of Hematopoietic Stem Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2351-2351
Author(s):  
Alexander M. de Bruin ◽  
Berend Hooibrink ◽  
Martijn A. Nolte
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Interferon Gamma ◽  
Chimeric Mice ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
The Impact

Abstract Abstract 2351 Regulation of hematopoiesis during stress situations, such as bacterial or viral infections, is crucial for the maintenance of sufficient numbers of cells in the blood. It has become clear that activated immune cells provide such feedback signals to the bone marrow. An important mediator in this respect is the pro-inflammatory cytokine Interferon-gamma (IFNγ), which is produced in the bone marrow by activated T cells during the course of an infection. As such, we have previously shown that T cell-derived IFNγ can directly influence the output of myeloid and erythroid cells. To address whether IFNγ can also influence the function of hematopoietic stem cells (HSCs), we cultured highly purified HSCs from murine bone marrow with or without IFNγ and found that IFNγ strongly reduced the absolute number of HSCs in these cultures, both phenotypically and functionally. We confirmed that the functional impact of IFNγ was due to a direct effect on HSCs and not mediated by more differentiated progenitors. In addition, IFNγ does not directly influence the quiescent state of purified HSC, nor their cell cycle entry. By labeling HSCs with CFSE, we found that IFNγ reduces HSC expansion in vitro by decreasing their proliferative capacity, but not their ability to differentiate. To investigate the impact of IFNγ on HSCs in vivo, we infected WT and IFNγ−/− mice with lymphocytic choriomeningitis virus (LCMV) and found that IFNγ severely impaired HSC recovery upon infection. Finally, to exclude indirect effects of IFNγ on other cell types we generated chimeric mice with bone marrow from both WT and IFNγR−/− mice. Infection of these mixed-chimeric mice with LCMV resulted in decreased recovery of WT HSCs, but not of IFNγR−/− HSCs in the same mouse, which formally demonstrates that IFNγ directly impairs the proliferation of HSCs in vivo. Based on these experiments we conclude that IFNγ reduces HSC self renewal both in vitro and in vivo. Importantly, we thereby challenge the current concept in literature that IFNγ would induce the proliferation of HSCs (Baldridge et al, Nature 2010). Our findings thus provide challenging new insight regarding the impact of immune activation on hematopoiesis and will contribute significantly to the scientific discussion concerning this process. Moreover, our data also provide an explanation for the occurrence of anemia and bone marrow failure in several human diseases in which IFNγ is chronically produced. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Role of Bone Marrow Mesenchymal Stem Cell Derived Extracellular Vesicles (MSC-EVs) in Normal and Abnormal Hematopoiesis and Their Therapeutic Potential

2020 ◽  
Vol 9 (3) ◽  
pp. 856 ◽  
Author(s):  
Aristea K. Batsali ◽  
Anthie Georgopoulou ◽  
Irene Mavroudi ◽  
Angelos Matheakakis ◽  
Charalampos G. Pontikoglou ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Extracellular Vesicles ◽  
Therapeutic Potential ◽  
Biological Effects ◽  
Potential Contribution ◽  
Scale Production ◽  
Hematopoietic Stem ◽  
The Impact

Mesenchymal stem cells (MSCs) represent a heterogeneous cellular population responsible for the support, maintenance, and regulation of normal hematopoietic stem cells (HSCs). In many hematological malignancies, however, MSCs are deregulated and may create an inhibitory microenvironment able to induce the disease initiation and/or progression. MSCs secrete soluble factors including extracellular vesicles (EVs), which may influence the bone marrow (BM) microenvironment via paracrine mechanisms. MSC-derived EVs (MSC-EVs) may even mimic the effects of MSCs from which they originate. Therefore, MSC-EVs contribute to the BM homeostasis but may also display multiple roles in the induction and maintenance of abnormal hematopoiesis. Compared to MSCs, MSC-EVs have been considered a more promising tool for therapeutic purposes including the prevention and treatment of Graft Versus Host Disease (GVHD) following allogenic HSC transplantation (HSCT). There are, however, still unanswered questions such as the molecular and cellular mechanisms associated with the supportive effect of MSC-EVs, the impact of the isolation, purification, large-scale production, storage conditions, MSC source, and donor characteristics on MSC-EV biological effects as well as the optimal dose and safety for clinical usage. This review summarizes the role of MSC-EVs in normal and malignant hematopoiesis and their potential contribution in treating GVHD.

Sign in / Sign up

Export Citation Format

Share Document