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Early severe impairment of hematopoietic stem and progenitor cells from the bone marrow caused by CLP sepsis and endotoxemia in a humanized mice model.

Skirecki T, Kawiak J, Machaj E, Pojda Z, Wasilewska D, Czubak J, Hoser G - Stem Cell Res Ther (2015)

Bottom Line: Both CLP and endotoxemia decreased (by 43 % and 37 %) cellularity of the BM.In contrast, in vitro LPS stimulated differentiation of CD34(+) CD38(-) HSCs but did not induce proliferation of these cells in contrast to the CD34(+) CD38(+) progenitors.It is suggestive that the Notch pathway contributed to this effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Flow Cytometry, The Center of Postgraduate Medical Education, Marymoncka 99/103, 01-813, Warsaw, Poland. tskirecki@gmail.com.

ABSTRACT

Introduction: An effective immune response to severe bacterial infections requires a robust production of the innate immunity cells from hematopoietic stem and progenitor cells (HSPCs) in a process called emergency myelopoiesis. In sepsis, an altered immune response that leads to a failure of bacterial clearance is often observed. In this study, we aimed to evaluate the impact of sepsis on human HSPCs in the bone marrow (BM) microenvironment of humanized mice subjected to acute endotoxemia and polymicrobial sepsis.

Methods: Humanized mice (hu-NSG) were generated by transplanting NOD.Cg-Prkdc/scidIL2rγ (NSG) mice with the human cord blood CD34(+) cells. Eight weeks after the transplantation, hu-NSG mice were subjected to sepsis induced by endotoxemia-Escherichia coli lipopolysaccharide (LPS)-or by cecal ligation and puncture (CLP). Twenty-four hours later, HSPCs from BM were analyzed by flow cytometry and colony-forming unit (CFU) assay. CLP after inhibition of Notch signaling was also performed. The effects of LPS on the in vitro proliferation of CD34(+) cells from human BM were tested by CellTrace Violet dye staining.

Results: The expression of Toll-like receptor 4 receptor was present among engrafted human HSPCs. Both CLP and endotoxemia decreased (by 43 % and 37 %) cellularity of the BM. In addition, in both models, accumulation of early CD34(+) CD38(-) HSCs was observed, but the number of CD34(+) CD38(+) progenitors decreased. After CLP, there was a 1.5-fold increase of proliferating CD34(+) CD38(-)Ki-67(+) cells. Moreover, CFU assay revealed a depressed (by 75 % after LPS and by 50 % after CLP) production of human hematopoietic colonies from the BM of septic mice. In contrast, in vitro LPS stimulated differentiation of CD34(+) CD38(-) HSCs but did not induce proliferation of these cells in contrast to the CD34(+) CD38(+) progenitors. CLP sepsis modulated the BM microenvironment by upregulation of Jagged-1 expression on non-hematopoietic cells, and the proliferation of HSCs was Notch-dependent.

Conclusions: CLP sepsis and endotoxemia induced a similar expansion and proliferation of early HSCs in the BM, while committed progenitors decreased. It is suggestive that the Notch pathway contributed to this effect. Targeting early hematopoiesis may be considered as a viable alternative in the existing arsenal of supportive therapies in sepsis.

No MeSH data available.


Related in: MedlinePlus

Modulation of the expression of TLR4 and CXCR4 receptors on human HSCs. Changes of TLR4 (a, c) and CXCR4 (e) expression on CD34+ CD38− cells 24 h after single LPS injection. Impact of CLP model on the modulation of TLR4 receptor expression (b, d) and CXCR4 expression (f). Representative histograms of TLR4 (g) and CXCR4 (h) expression on CD34+ CD38− HSCs from control and CLP mice are presented. n = 6, *P < 0.05, **P < 0.01. CLP cecum ligation and puncture, GMF geometric mean fluorescence, HSC hematopoietic stem cell, LPS lipopolysaccharide, TLR Toll-like receptor
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Fig4: Modulation of the expression of TLR4 and CXCR4 receptors on human HSCs. Changes of TLR4 (a, c) and CXCR4 (e) expression on CD34+ CD38− cells 24 h after single LPS injection. Impact of CLP model on the modulation of TLR4 receptor expression (b, d) and CXCR4 expression (f). Representative histograms of TLR4 (g) and CXCR4 (h) expression on CD34+ CD38− HSCs from control and CLP mice are presented. n = 6, *P < 0.05, **P < 0.01. CLP cecum ligation and puncture, GMF geometric mean fluorescence, HSC hematopoietic stem cell, LPS lipopolysaccharide, TLR Toll-like receptor

Mentions: Given that the HSPC fate can be influenced via TLR receptors and that TLR4-mediated recognition of pathogens is considered a key signaling axis in Gram-negative and polymicrobial infections, we then analyzed modulation of the TLR4 expression. In CLP sepsis, there was a two-fold increase in the frequency of the TLR4-positive CD34+ CD38− cells (55 ± 13.4 % versus 26.1 ± 13.4 %; Fig. 4a-d). Moreover, the geometric mean fluorescence of anti-TLR4 staining increased by 43 % (Fig. 4b, d, g). Similar results were obtained in endotoxemia: the TLR4-positive CD34+ CD38− cells and the fluorescence intensity increased by 63 % and 46 %, respectively (Fig. 4a, c).Fig. 4


Early severe impairment of hematopoietic stem and progenitor cells from the bone marrow caused by CLP sepsis and endotoxemia in a humanized mice model.

Skirecki T, Kawiak J, Machaj E, Pojda Z, Wasilewska D, Czubak J, Hoser G - Stem Cell Res Ther (2015)

Modulation of the expression of TLR4 and CXCR4 receptors on human HSCs. Changes of TLR4 (a, c) and CXCR4 (e) expression on CD34+ CD38− cells 24 h after single LPS injection. Impact of CLP model on the modulation of TLR4 receptor expression (b, d) and CXCR4 expression (f). Representative histograms of TLR4 (g) and CXCR4 (h) expression on CD34+ CD38− HSCs from control and CLP mice are presented. n = 6, *P < 0.05, **P < 0.01. CLP cecum ligation and puncture, GMF geometric mean fluorescence, HSC hematopoietic stem cell, LPS lipopolysaccharide, TLR Toll-like receptor
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4536694&req=5

Fig4: Modulation of the expression of TLR4 and CXCR4 receptors on human HSCs. Changes of TLR4 (a, c) and CXCR4 (e) expression on CD34+ CD38− cells 24 h after single LPS injection. Impact of CLP model on the modulation of TLR4 receptor expression (b, d) and CXCR4 expression (f). Representative histograms of TLR4 (g) and CXCR4 (h) expression on CD34+ CD38− HSCs from control and CLP mice are presented. n = 6, *P < 0.05, **P < 0.01. CLP cecum ligation and puncture, GMF geometric mean fluorescence, HSC hematopoietic stem cell, LPS lipopolysaccharide, TLR Toll-like receptor
Mentions: Given that the HSPC fate can be influenced via TLR receptors and that TLR4-mediated recognition of pathogens is considered a key signaling axis in Gram-negative and polymicrobial infections, we then analyzed modulation of the TLR4 expression. In CLP sepsis, there was a two-fold increase in the frequency of the TLR4-positive CD34+ CD38− cells (55 ± 13.4 % versus 26.1 ± 13.4 %; Fig. 4a-d). Moreover, the geometric mean fluorescence of anti-TLR4 staining increased by 43 % (Fig. 4b, d, g). Similar results were obtained in endotoxemia: the TLR4-positive CD34+ CD38− cells and the fluorescence intensity increased by 63 % and 46 %, respectively (Fig. 4a, c).Fig. 4

Bottom Line: Both CLP and endotoxemia decreased (by 43 % and 37 %) cellularity of the BM.In contrast, in vitro LPS stimulated differentiation of CD34(+) CD38(-) HSCs but did not induce proliferation of these cells in contrast to the CD34(+) CD38(+) progenitors.It is suggestive that the Notch pathway contributed to this effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Flow Cytometry, The Center of Postgraduate Medical Education, Marymoncka 99/103, 01-813, Warsaw, Poland. tskirecki@gmail.com.

ABSTRACT

Introduction: An effective immune response to severe bacterial infections requires a robust production of the innate immunity cells from hematopoietic stem and progenitor cells (HSPCs) in a process called emergency myelopoiesis. In sepsis, an altered immune response that leads to a failure of bacterial clearance is often observed. In this study, we aimed to evaluate the impact of sepsis on human HSPCs in the bone marrow (BM) microenvironment of humanized mice subjected to acute endotoxemia and polymicrobial sepsis.

Methods: Humanized mice (hu-NSG) were generated by transplanting NOD.Cg-Prkdc/scidIL2rγ (NSG) mice with the human cord blood CD34(+) cells. Eight weeks after the transplantation, hu-NSG mice were subjected to sepsis induced by endotoxemia-Escherichia coli lipopolysaccharide (LPS)-or by cecal ligation and puncture (CLP). Twenty-four hours later, HSPCs from BM were analyzed by flow cytometry and colony-forming unit (CFU) assay. CLP after inhibition of Notch signaling was also performed. The effects of LPS on the in vitro proliferation of CD34(+) cells from human BM were tested by CellTrace Violet dye staining.

Results: The expression of Toll-like receptor 4 receptor was present among engrafted human HSPCs. Both CLP and endotoxemia decreased (by 43 % and 37 %) cellularity of the BM. In addition, in both models, accumulation of early CD34(+) CD38(-) HSCs was observed, but the number of CD34(+) CD38(+) progenitors decreased. After CLP, there was a 1.5-fold increase of proliferating CD34(+) CD38(-)Ki-67(+) cells. Moreover, CFU assay revealed a depressed (by 75 % after LPS and by 50 % after CLP) production of human hematopoietic colonies from the BM of septic mice. In contrast, in vitro LPS stimulated differentiation of CD34(+) CD38(-) HSCs but did not induce proliferation of these cells in contrast to the CD34(+) CD38(+) progenitors. CLP sepsis modulated the BM microenvironment by upregulation of Jagged-1 expression on non-hematopoietic cells, and the proliferation of HSCs was Notch-dependent.

Conclusions: CLP sepsis and endotoxemia induced a similar expansion and proliferation of early HSCs in the BM, while committed progenitors decreased. It is suggestive that the Notch pathway contributed to this effect. Targeting early hematopoiesis may be considered as a viable alternative in the existing arsenal of supportive therapies in sepsis.

No MeSH data available.


Related in: MedlinePlus