Human mesenchymal stem cells promote CD34+hematopoietic stem cell proliferation with preserved red blood cell differentiation capacity

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.

Download Full-text

Excessive Hematopoietic Stem Cell Proliferation Leads to Chromosomal Instability

Blood ◽

10.1182/blood.v112.11.4772.4772 ◽

2008 ◽

Vol 112 (11) ◽

pp. 4772-4772

Author(s):

Liliana Souza ◽

Natalyn Hawk ◽

Sweta Sengupta ◽

Carlos Cabrera ◽

Morgan L. McLemore

Keyword(s):

Cell Cycle ◽

Stem Cells ◽

Cell Proliferation ◽

Stem Cell ◽

Chromosomal Instability ◽

Wild Type ◽

Dna Breaks ◽

Hematopoietic Stem ◽

Stem Cell Proliferation ◽

Double Stranded Dna

Abstract Truncation mutations in the granulocyte colony stimulating factor receptor (G-CSFR), common in severe congenital neutropenia (SCN), lead to excessive stem cell proliferation in response to G-CSF. These G-CSFR mutants are (at least indirectly) implicated in the progression of these patients to acute leukemia. Since SCN patients require continuous G-CSF treatment throughout their lifespan, we hypothesize that excessive stem cell proliferation can lead to DNA damage. Stem cells are relatively quiescent and rarely enter the cell cycle under normal conditions. During the cell cycle cells generate approximately 5000 single strand DNA lesions per nucleus (Vilenchik and Knudson, 2003). Approximately 1% of these lesions are ultimately converted to double strand DNA breaks (DSBs). Hematopoietic stem cells are found within the Sca+ ckit+ Lin- (KLS) population. Wild type and mice bearing a mutant G-CSFR similar to that found in patients with SCN were treated with G-CSF. After 21 days of treatment with G-CSF (10 ug/kg/day), the KLS population in the bone marrow increased four-fold in wild type mice and eight-fold in mutant mice. We isolated Lin-Sca+ bone marrow cells from these G-CSF treated mice and evaluated for the presence of double stranded DNA breaks by staining with anti-phospho-H2AX by immunofluorescence. H2AX is a histone whose phosphorylated form localizes to the site of double stranded DNA breaks. The results showed that there is an 8-fold increase in the DSB in wild type Lin-Sca+ and 10-fold in mutant Lin-Sca+ when compared to cells from untreated mice. This data suggests that excessive proliferation can contribute to an increase in DSBs in hematopoietic stem cells. Investigation of potential mechanisms contributing to DSB formation are ongoing. Understanding the causes and trends of chromosomal instability would improve our understanding of leukemogenesis and potentially reveal novel treatment strategies.

Download Full-text

Reactive Oxygen Species Are Required for Human Mesenchymal Stem Cells to Initiate Proliferation after the Quiescence Exit

Oxidative Medicine and Cellular Longevity ◽

10.1155/2015/502105 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 27

Author(s):

O. G. Lyublinskaya ◽

Ya. G. Borisov ◽

N. A. Pugovkina ◽

I. S. Smirnova ◽

Ju. V. Obidina ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Cell Cycle ◽

Stem Cells ◽

Cell Proliferation ◽

Mesenchymal Stem Cells ◽

Stem Cell ◽

Human Mesenchymal Stem Cells ◽

S Phase ◽

Oxygen Species ◽

Antioxidant Treatment

The present study focuses on the involvement of reactive oxygen species (ROS) in the process of mesenchymal stem cells “waking up” and entering the cell cycle after the quiescence. Using human endometrial mesenchymal stem cells (eMSCs), we showed that intracellular basal ROS level is positively correlated with the proliferative status of the cell cultures. Our experiments with the eMSCs synchronized in the G0phase of the cell cycle revealed a transient increase in the ROS level upon the quiescence exit after stimulation of the cell proliferation. This increase was registered before the eMSC entry to the S-phase of the cell cycle, and elimination of this increase by antioxidants (N-acetyl-L-cysteine, Tempol, and Resveratrol) blocked G1–S-phase transition. Similarly, a cell cycle arrest which resulted from the antioxidant treatment was observed in the experiments with synchronized human mesenchymal stem cells derived from the adipose tissue. Thus, we showed that physiologically relevant level of ROS is required for the initiation of human mesenchymal stem cell proliferation and that low levels of ROS due to the antioxidant treatment can block the stem cell self-renewal.

Download Full-text

Does primary myelofibrosis involve a defective stem cell niche? From concept to evidence

Blood ◽

10.1182/blood-2008-06-158386 ◽

2008 ◽

Vol 112 (8) ◽

pp. 3026-3035 ◽

Cited By ~ 89

Author(s):

Jean-Jacques Lataillade ◽

Olivier Pierre-Louis ◽

Hans Carl Hasselbalch ◽

Georges Uzan ◽

Claude Jasmin ◽

...

Keyword(s):

Stem Cells ◽

Bone Marrow ◽

Cell Proliferation ◽

Stem Cell ◽

Hematopoietic Stem Cells ◽

Stem Cell Niche ◽

Primary Myelofibrosis ◽

Hematopoietic Stem ◽

Stem Cell Proliferation ◽

Cell Niche

Abstract Primary myelofibrosis (PMF) is the rarest and the most severe Philadelphia-negative chronic myeloproliferative syndrome. By associating a clonal proliferation and a mobilization of hematopoietic stem cells from bone marrow to spleen with profound alterations of the stroma, PMF is a remarkable model in which deregulation of the stem cell niche is of utmost importance for the disease development. This paper reviews key data suggesting that an imbalance between endosteal and vascular niches participates in the development of clonal stem cell proliferation. Mechanisms by which bone marrow niches are altered with ensuing mobilization and homing of neoplastic hematopoietic stem cells in new or reinitialized niches in the spleen and liver are examined. Differences between signals delivered by both endosteal and vascular niches in the bone marrow and spleen of patients as well as the responsiveness of PMF stem cells to their specific signals are discussed. A proposal for integrating a potential role for the JAK2 mutation in their altered sensitivity is made. A better understanding of the cross talk between stem cells and their niche should imply new therapeutic strategies targeting not only intrinsic defects in stem cell signaling but also regulatory hematopoietic niche–derived signals and, consequently, stem cell proliferation.

Download Full-text