Cell Fate Modulation by Microvesicles: Transcriptionally-Mediated and Long Term in Nature

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4801-4801
Author(s):  
Peter J Quesenberry

Abstract Abstract 4801 Cell-derived membrane enclosed vesicles containing mRNA, protein, microRNA, and DNA, can enter cells and effect a phenotype change. We have shown that lung-derived microvesicles enter marrow cells inducing them to express pulmonary epithelial cell-specific protein and mRNA, a variety of microRNA and to enhance their capacity to engraft in irradiated mice and express the phenotype of type II pneumocytes (Aliotta et al, Exp Hematol 38,2010). In the present studies using rat/mouse hybrid cultures and measuring species-specific mRNA, we have shown that immediately after co-culture of rat lung across from mouse marrow, mouse marrow cells express both rat and mouse specific surfactants B and C mRNA. However, when these cells are cultured in steel factor supported long-term culture, rat-specific mRNA disappears rapidly, while mouse-specific mRNA persists out to 12 weeks in liquid culture. Identical studies with rat liver cultured across from mouse marrow have shown early expression in mouse marrow of both rat and mouse albumin mRNA, but in long term in vitro culture, expression of albumin mRNA was mouse-specific. Thus, the major long-term persistent event is an alteration of transcription in the target marrow cells. In a similar fashion, marrow modulated by lung microvesicles in vitro and engrafted into lethally irradiated (950 cGy split dose) mice, evidences expression of pulmonary epithelial cell-specific mRNA or protein (surfactants) in host lung, marrow, thymus, spleen and liver 6 weeks after engraftment – the furthest time tested. These results indicate that microvesicle cell fate modulation is biologically meaningful and represents an important new mechanism for cell phenotype determination. Disclosures: No relevant conflicts of interest to declare.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4799-4799
Author(s):  
Jason M Aliotta ◽  
Mandy Pereira ◽  
Ashley Amaral ◽  
Mark S Dooner ◽  
Michael DelTatto ◽  
...  

Abstract Abstract 4799 We have previously shown that microvesicles derived from irradiated murine lung cells enter murine bone marrow cells and induce expression of the pulmonary epithelial cell-specific mRNAs Surfactants A-D (Sp-A-D), Aquaporin-5 (Aq-5) and Clara Cell Specific Protein (CCSP). The early mRNA increases are due to direct delivery of mRNA and due to the transfer of a transcription factor to marrow cells (Aliotta JM, et al, Exp Hematol, 2010). The modulated marrow cells produce pulmonary epithelial cell-specific protein and have an enhanced ability to convert into pulmonary epithelial cells after transplantation into lethally-irradiated mice. In the present studies, we evaluated the stability of pulmonary epithelial cell-specific mRNA expression in cytokine-stimulated liquid culture and after in vivo transplantation into lethally-irradiated mice. Whole bone marrow cells isolated from C57BL/6 mice were cultured for seven days opposite C57BL/6 lung fragments, but separated from them by a 0.4 micron cell-impermeable membrane. Marrow cells were then either infused into lethally-irradiated C57BL/6 mice or established in culture with DMEM supplemented with IL-3, IL-6, IL-11 and steel factor. Engrafted mice were sacrificed six weeks after transplantation and real-time RT-PCR was carried out on marrow, liver, spleen and thymus tissue. Expression of Sp-A, B and D, CCSP and Aq-5 were variably seen in all tissues and increases over control ranged from 12-fold to 58-fold. Liquid culture was analyzed every two weeks out to 12 weeks and high levels of expression of different pulmonary epithelial cell-specific mRNAs and proteins (by western blot and Immunohistochemical staining) were observed. In order to determine the mechanism for the increased expression in culture, we established co-cultures of Fischer-344 rat lung opposite C57BL/6 mouse bone marrow cells and, using species-specific primers, determined whether the increased pulmonary epithelial cell-specific mRNA expression at each time point of secondary cytokine-supported culture was rat or mouse-specific. In every instance, the pulmonary epithelial cell-specific mRNA which was detected was mouse-specific, not rat-specific, and thus the long-term expression of lung-specific mRNA in mouse marrow was due to induced transcription by the mouse marrow cells. These data indicate that lung-derived microvesicles induce long-term stable epigenetic changes in marrow cells and suggests that the genetic changes induced by tissue microvesicles in neighboring cells may be biologically important. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4509-4509
Author(s):  
Jason M Aliotta ◽  
Mandy Pereira ◽  
Mark Dooner ◽  
Gerri Dooner ◽  
Bharat Ramratnam ◽  
...  

Abstract Abstract 4509 Objective We have previously reported that lung-derived microvesicles (MVs) can enter target marrow cells, resulting in increased levels of lung-specific mRNAs (Stem Cells 25:2245, 2007). Marrow cells which have been exposed to MVs also show increased production of pulmonary epithelial cells after transplantation into irradiated mice. The present studies have addressed the universality of the mRNA modulation and the underlying mechanisms. Methods/Results Co-culture of heart, brain, liver, and lung tissue across from murine marrow, but separated by a 0.4 micron cell-impermeable membrane, show tissue specific elevations of mRNA. MVs were found to contain lung-specific mRNA and 200 microRNAs. Proteomic studies of MVs showed up to 75 individual proteins, some of which are known to be associated with MV biogenesis and trafficking. Studies using rat/mouse hybrid cultures demonstrated that the target cell induced lung-specific mRNA elevations were mediated by transcriptional mechanisms. In these experiments, rat lung was co-cultured across from murine marrow cells and RT-PCR was performed using rat or mouse-specific primers for surfactant B. High levels of rat-specific surfactant B were seen in the co-cultured marrow cells indicating that transcription had been induced in the target cells. These conclusions were supported by additional studies employing the transcription factor inhibitors actinomycin-D and alpha-amantin. RNase treatment of conditioned media prior to marrow cell co-culture suggested that transfer of RNA may be involved in these mRNA elevations. However, our transcriptional studies indicate that we are not observing a simple transfer of MV lung-specific mRNA. One possible mechanism may be transfer of microRNA with epigenetic changes resulting in lung-specific mRNA production. Conclusion In summary, these observations suggest the existence of unique pathways for information transfer and cell phenotype determination. MV transfer could represent an underlying mechanism for much of the previous reported stem cell plasticity in different tissues. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
1989 ◽  
Vol 74 (3) ◽  
pp. 930-939 ◽  
Author(s):  
SJ Szilvassy ◽  
PM Lansdorp ◽  
RK Humphries ◽  
AC Eaves ◽  
CJ Eaves

Abstract A simple procedure is described for the quantitation and enrichment of murine hematopoietic cells with the capacity for long-term repopulation of lymphoid and myeloid tissues in lethally irradiated mice. To ensure detection of the most primitive marrow cells with this potential, we used a competitive assay in which female recipients were injected with male “test” cells and 1 to 2 x 10(5) “compromised” female marrow cells with normal short-term repopulating ability, but whose long-term repopulating ability had been reduced by serial transplantation. Primitive hematopoietic cells were purified by flow cytometry and sorting based on their forward and orthogonal light-scattering properties, and Thy-1 and H-2K antigen expression. Enrichment profiles for normal marrow, and marrow of mice injected with 5-fluorouracil (5- FU) four days previously, were established for each of these parameters using an in vitro assay for high proliferative potential, pluripotent colony-forming cells. When all four parameters were gated simultaneously, these clonogenic cells were enriched 100-fold. Both day 9 and day 12 CFU-S were copurified; however, the purity (23%) and enrichment (75-fold) of day 12 CFU-S in the sorted population was greater with 5-FU-treated cells. Five hundred of the sorted 5-FU marrow cells consistently repopulated recipient lymphoid and myeloid tissues (greater than 50% male, 1 to 3 months post-transplant) when co-injected with 1 to 2 x 10(5) compromised female marrow cells, and approximately 100 were sufficient to achieve the same result in 50% of recipients under the same conditions. This relatively simple purification and assay strategy should facilitate further analysis of the heterogeneity and regulation of stem cells that maintain hematopoiesis in vivo.


2011 ◽  
Vol 301 (2) ◽  
pp. C522-C529 ◽  
Author(s):  
Justine Elliott ◽  
Nadezhda N. Zheleznova ◽  
Patricia D. Wilson

c-Src is a non-receptor tyrosine kinase whose activity is induced by phosphorylation at Y418 and translocation from the cytoplasm to the cell membrane. Increased activity of c-Src has been associated with cell proliferation, matrix adhesion, motility, and apoptosis in tumors. Immunohistochemistry suggested that activated (pY418)-Src activity is increased in cyst-lining autosomal dominant polycystic kidney disease (ADPKD) epithelial cells in human and mouse ADPKD. Western blot analysis showed that SKI-606 (Wyeth) is a specific inhibitor of pY418-Src without demonstrable effects on epidermal growth factor receptor or ErbB2 activity in renal epithelia. In vitro studies on mouse inner medullary collecting duct (mIMCD) cells and human ADPKD cyst-lining epithelial cells showed that SKI-606 inhibited epithelial cell proliferation over a 24-h time frame. In addition, SKI-606 treatment caused a striking statistically significant decrease in adhesion of mIMCD and human ADPKD to extracellular collagen matrix. Retained viability of unattached cells was consistent with a primary effect on epithelial cell anchorage dependence mediated by the loss of extracellular matrix (ECM)-attachment due to α2β1-integrin function. SKI-606-mediated attenuation of the human ADPKD hyperproliferative and hyper-ECM-adhesive epithelial cell phenotype in vitro was paralleled by retardation of the renal cystic phenotype of Pkd1 orthologous ADPKD heterozygous mice in vivo. This suggests that SKI-606 has dual effects on cystic epithelial cell proliferation and ECM adhesion and may have therapeutic potential for ADPKD patients.


Blood ◽  
1996 ◽  
Vol 88 (11) ◽  
pp. 4149-4158 ◽  
Author(s):  
M Trevisan ◽  
XQ Yan ◽  
NN Iscove

Abstract This investigation was directed at separating long-term reconstituting (LTR) stem cells in normal murine marrow from hematopoietic precursors detectable in short-term assays in vitro and in vivo, and then at determining whether purified LTR cells could themselves form colonies in culture. To do so, it was first necessary to identify culture conditions that would induce their growth while preserving their long- term reconstituting capacity. Marrow was cultured with various cytokines in liquid suspension for 4 days, after which the surviving LTR activity was quantitated in a competitive in vivo assay. Activity was preserved near input levels with combined murine c-kit ligand (KL), interleukin-1 (IL-1), IL-6, and IL-11. When the cultures also included tritiated or unlabeled thymidine, LTR potential was eliminated, indicating that essentially all LTR cells were induced into cell cycle with these cytokines. To purify them, marrow was sorted on the basis of Ly6A expression and Rhodamine 123 retention. The Ly6AhiRh123ls fraction contained 85% of total recovered LTR activity but only 1% of the recovered cells measured by multilineage colony formation in spleens or in vitro. This fraction was cultured in methyl cellulose with KL, IL-1, IL-6, and IL-11 for 4 to 6 days, after which colonies were isolated and injected into mice. High levels of permanent reconstitution were achievable in sublethally irradiated W41/W41 mice after the injection of a single reconstituting unit, and limiting dilution analysis estimated the frequency of multilineage LTR at 1 in 11,200 unpurified adult marrow cells. In either lethally irradiated normal or sublethally irradiated W41/W41 mice, 1-year lymphomyeloid reconstitutions were obtained from 1 in 65 to 84 colonies of 2 to 16 dispersed cells, but not from larger colonies or those with clumped cells. The results establish that resting marrow LTR cells can be separated from almost all of the more advanced clonogenic cells that are still pluripotential, can be induced to cycle in culture by defined cytokines with preservation of their reconstituting potential, and can be manipulated and assayed efficiently at single-cell and colony levels.


2013 ◽  
Vol 378 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Changgong Li ◽  
Aimin Li ◽  
Yiming Xing ◽  
Min Li ◽  
Belinda Chan ◽  
...  

Blood ◽  
1999 ◽  
Vol 94 (8) ◽  
pp. 2548-2554 ◽  
Author(s):  
Takashi Sato ◽  
Joseph H. Laver ◽  
Makio Ogawa

We used a mouse transplantation model to address the recent controversy about CD34 expression by hematopoietic stem cells. Cells from Ly-5.1 C57BL/6 mice were used as donor cells and Ly-5.2 mice were the recipients. The test cells were transplanted together with compromised marrow cells of Ly-5.2 mice. First, we confirmed that the majority of the stem cells with long-term engraftment capabilities of normal adult mice are CD34−. We then observed that, after the injection of 150 mg/kg 5-fluorouracil (5-FU), stem cells may be found in both CD34− and CD34+ cell populations. These results indicated that activated stem cells express CD34. We tested this hypothesis also by using in vitro expansion with interleukin-11 and steel factor of lineage−c-kit+ Sca-1+ CD34− bone marrow cells of normal mice. When the cells expanded for 1 week were separated into CD34− and CD34+ cell populations and tested for their engraftment capabilities, only CD34+ cells were capable of 2 to 5 months of engraftment. Finally, we tested reversion of CD34+ stem cells to CD34− state. We transplanted Ly-5.1 CD34+post–5-FU marrow cells into Ly-5.2 primary recipients and, after the marrow achieved steady state, tested the Ly-5.1 cells of the primary recipients for their engraftment capabilities in Ly-5.2 secondary recipients. The majority of the Ly-5.1 stem cells with long-term engraftment capability were in the CD34− cell fraction, indicating the reversion of CD34+ to CD34−stem cells. These observations clearly demonstrated that CD34 expression reflects the activation state of hematopoietic stem cells and that this is reversible.


1992 ◽  
Vol 176 (2) ◽  
pp. 351-361 ◽  
Author(s):  
H Kodama ◽  
M Nose ◽  
Y Yamaguchi ◽  
J Tsunoda ◽  
T Suda ◽  
...  

The preadipose cell line, PA6, can support long-term hemopoiesis. Frequency of the hemopoietic stem cells capable of sustaining hemopoiesis in cocultures of bone marrow cells and PA6 cells for 6 wk was 1/5.3 x 10(4) bone marrow cells. In the group of dishes into which bone marrow cells had been inoculated at 2.5 x 10(4) cells/dish, 3 of 19 dishes (16%) contained stem cells capable of reconstituting erythropoiesis of WBB6F1-W/Wv mice, indicating that PA6 cells can support the proliferation of primitive hemopoietic stem cells. When the cocultures were treated with an antagonistic anti-c-kit monoclonal antibody, ACK2, only a small number of day 12 spleen colony-forming units survived; and hemopoiesis was severely reduced. However, when the cocultures were continued with antibody-free medium, hemopoiesis dramatically recovered. To examine the proliferative properties of the ACK2-resistant stem cells, we developed a colony assay system by modifying our coculture system. Sequential observations of the development of individual colonies and their disappearance demonstrated that the stem cells having higher proliferative capacity preferentially survive the ACK2 treatment. Furthermore, cells of subclones of the PA6 clone that were incapable of supporting long-term hemopoiesis expressed mRNA for the c-kit ligand. These results suggest that a mechanism(s) other than that involving c-kit receptor and its ligand plays an important role in the survival and proliferation of primitive hemopoietic stem cells.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 446-446
Author(s):  
Alejo E Rodriguez-Fraticelli ◽  
Caleb S Weinreb ◽  
Allon Moshe Klein ◽  
Shou-Wen Wang ◽  
Fernando D Camargo

Blood regeneration upon transplantation relies on the activity of long-term repopulating hematopoietic stem cells (LT-HSCs). One of the major controversies in hematopoiesis relates to the apparently different properties that HSCs have in transplantation versus unperturbed settings. In unperturbed steady state hematopoiesis, the most potent HSCs appear to be mostly dormant, and only producing platelet-lineage cells. In turn, upon transplant, even a single transplanted HSC can actively divide and regenerate hundreds of millions of blood progenitors of all lineages. It would thus appear that HSCs have different fundamental properties in each study system. However, most transplantation studies have only tracked the lineage output of the transplanted HSC clones, and rarely the regeneration of the HSC compartment itself. In addition, clonal assays have not been performed at sufficient resolution to fully capture the diversity and clonal complexity of the regenerated HSC compartment. Here, we have used expressible barcodes, which can be sequenced in conventional single cell RNAseq assays, to simultaneously record the functional outcomes and transcriptional states of thousands of HSCs. Our analysis revealed multiple clonal HSC behaviors following transplantation that drastically differ in their differentiation activity, lineage-bias and self-renewal. Surprisingly, we witnessed a large fraction of clones that efficiently repopulate the HSC compartment but show limited contribution to differentiated progeny. Furthermore, these inactive clones have increased competitive multilineage serial repopulating capacity, implying that shortly after transplant a subset of clones reestablishes the native-like LT-HSC behaviors. Our results also argue that this clonal distribution of labor is controlled by cell autonomous, heritable properties (i.e. the epigenetic cell state). Then, using only our clonal readouts to segregate single HSC transcriptomes, we unveiled the transcriptional signatures that associated with unique HSC outcomes (platelet bias, clonal expansion, dormancy, etc.) and unraveled, for the first time, a gene signature for functional long-term serially repopulating clones. We interrogated the drivers of this cell state using an in vivo inducible CRISPR screening and identified 5 novel regulators that are required to regenerate the HSC compartment in a cell autonomous fashion. In conclusion, we demonstrate that functional LT-HSCs share more similar properties in native and transplantation hematopoiesis than previously expected. Consequently, we unveil a definition of the essential, common functional properties of HSCs and the molecular programs that control them. Figure 1 Disclosures No relevant conflicts of interest to declare.


2002 ◽  
Vol 22 (8) ◽  
pp. 2830-2841 ◽  
Author(s):  
Kevin G. Leong ◽  
Xiaolong Hu ◽  
Linheng Li ◽  
Michela Noseda ◽  
Bruno Larrivée ◽  
...  

ABSTRACT Notch4 is a member of the Notch family of transmembrane receptors that is expressed primarily on endothelial cells. Activation of Notch in various cell systems has been shown to regulate cell fate decisions. The sprouting of endothelial cells from microvessels, or angiogenesis, involves the modulation of the endothelial cell phenotype. Based on the function of other Notch family members and the expression pattern of Notch4, we postulated that Notch4 activation would modulate angiogenesis. Using an in vitro endothelial-sprouting assay, we show that expression of constitutively active Notch4 in human dermal microvascular endothelial cells (HMEC-1) inhibits endothelial sprouting. We also show that activated Notch4 inhibits vascular endothelial growth factor (VEGF)-induced angiogenesis in the chick chorioallantoic membrane in vivo. Activated Notch4 does not inhibit HMEC-1 proliferation or migration through fibrinogen. However, migration through collagen is inhibited. Our data show that Notch4 cells exhibit increased β1-integrin-mediated adhesion to collagen. HMEC-1 expressing activated Notch4 do not have increased surface expression of β1-integrins. Rather, we demonstrate that Notch4-expressing cells display β1-integrin in an active, high-affinity conformation. Furthermore, using function-activating β1-integrin antibodies, we demonstrate that activation of β1-integrins is sufficient to inhibit VEGF-induced endothelial sprouting in vitro and angiogenesis in vivo. Our findings suggest that constitutive Notch4 activation in endothelial cells inhibits angiogenesis in part by promoting β1-integrin-mediated adhesion to the underlying matrix.


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