Contributions
Abstract: P725
Type: Poster presentation
Session title: Myelodysplastic syndromes - Biology & Translational Research
Background
The crosstalk between the mutant hematopoietic stem and progenitor cells and the bone marrow microenvironment plays an important role in the pathogenesis of myelodysplastic syndromes (MDS). Mesenchymal stromal cells (MSC) represent one of the key cellular elements in this context. The functional properties of MDS-derived MSCs including impaired hematopoietic support, as well as increased senescence and defective osteogenic differentiation have been extensively studied. Additionally, the detrimental effect of high erythropoietin (Epo) concentration on MDS-MSCs has been demonstrated by our group. However, whether these deficiencies are associated with cellular metabolic changes has not been hitherto addressed.
Aims
We aimed to assess the basal metabolic characteristics in MDS-derived MSCs and the effect of Epo on their energetic profile in vitro.
Methods
MSC from bone marrow aspirates of patients with MDS (low risk n=3, MDS del5q n=1, chronic myelomonocytic leukemia n=2, high risk n=3) or age-adjusted healthy donors (n=3) were isolated by Ficoll density centrifugation and plastic adherent culture. Metabolic measurements were performed before and after incubation with Epo (50 IU/ml) for 2 days. Seahorse X96 Flux Analyzer (Seahorse Biosciences, Billerica, MA, USA) was used to analyse glucose metabolism by oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Metabolite concentrations were measured in the culture supernatants using NMR spectroscopy.
Results
MSC from healthy donors demonstrated a higher OCR/ECAR ratio compared to MDS counterparts (6.19±4,71 vs 1.14±0.28, p=0.005), suggesting enhanced glycolysis engagement of MDS-MSCs. This was confirmed by increased levels of lactate in the culture medium from MDS-MSCs after 48 hours of cultivation (healthy: 3.78±0.28 mM vs MDS: 6.75±2.35 mM, p=0.049), whereas the concentrations of pyruvate, alanine and acetate did not differ. Treatment with Epo resulted in a significant increase of the OCR/ECAR ratio (from 1.14±0.28 to 3.25±1.75, p=0.003) in MDS-MSCs, whereas changes in healthy MSCs were not significant (from 6.19±4,71 to 3.81±1.86, p=0.46).
Conclusion
In contrast to healthy MSCs which rely mainly on mitochondrial respiration, MDS-MSCs preferentially utilize the glycolytic pathway under normoxic conditions in vitro. Epo treatment leads to increased mitochondrial respiration in MDS-MSCs, but not in healthy counterparts. Whether this effect has a causative link to the disturbed function of MDS-MSCs remains to be clarified.
Keyword(s): Erythropoietin, Mesenchymal stem cell, Myelodysplastic syndrome
Abstract: P725
Type: Poster presentation
Session title: Myelodysplastic syndromes - Biology & Translational Research
Background
The crosstalk between the mutant hematopoietic stem and progenitor cells and the bone marrow microenvironment plays an important role in the pathogenesis of myelodysplastic syndromes (MDS). Mesenchymal stromal cells (MSC) represent one of the key cellular elements in this context. The functional properties of MDS-derived MSCs including impaired hematopoietic support, as well as increased senescence and defective osteogenic differentiation have been extensively studied. Additionally, the detrimental effect of high erythropoietin (Epo) concentration on MDS-MSCs has been demonstrated by our group. However, whether these deficiencies are associated with cellular metabolic changes has not been hitherto addressed.
Aims
We aimed to assess the basal metabolic characteristics in MDS-derived MSCs and the effect of Epo on their energetic profile in vitro.
Methods
MSC from bone marrow aspirates of patients with MDS (low risk n=3, MDS del5q n=1, chronic myelomonocytic leukemia n=2, high risk n=3) or age-adjusted healthy donors (n=3) were isolated by Ficoll density centrifugation and plastic adherent culture. Metabolic measurements were performed before and after incubation with Epo (50 IU/ml) for 2 days. Seahorse X96 Flux Analyzer (Seahorse Biosciences, Billerica, MA, USA) was used to analyse glucose metabolism by oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). Metabolite concentrations were measured in the culture supernatants using NMR spectroscopy.
Results
MSC from healthy donors demonstrated a higher OCR/ECAR ratio compared to MDS counterparts (6.19±4,71 vs 1.14±0.28, p=0.005), suggesting enhanced glycolysis engagement of MDS-MSCs. This was confirmed by increased levels of lactate in the culture medium from MDS-MSCs after 48 hours of cultivation (healthy: 3.78±0.28 mM vs MDS: 6.75±2.35 mM, p=0.049), whereas the concentrations of pyruvate, alanine and acetate did not differ. Treatment with Epo resulted in a significant increase of the OCR/ECAR ratio (from 1.14±0.28 to 3.25±1.75, p=0.003) in MDS-MSCs, whereas changes in healthy MSCs were not significant (from 6.19±4,71 to 3.81±1.86, p=0.46).
Conclusion
In contrast to healthy MSCs which rely mainly on mitochondrial respiration, MDS-MSCs preferentially utilize the glycolytic pathway under normoxic conditions in vitro. Epo treatment leads to increased mitochondrial respiration in MDS-MSCs, but not in healthy counterparts. Whether this effect has a causative link to the disturbed function of MDS-MSCs remains to be clarified.
Keyword(s): Erythropoietin, Mesenchymal stem cell, Myelodysplastic syndrome