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Increased oxygen consumption and OXPHOS potential in superhealer mesenchymal stem cells.

Hughey CC, Alfaro MP, Belke DD, Rottman JN, Young PP, Wasserman DH, Shearer J - Cell Regen (Lond) (2012)

Bottom Line: Additionally, glutamate/malate succinate-supported oxygen consumption in permeabilized cells was elevated approximately 1.25- and 1.4-fold in the MRL-MSCs, respectively.The results from intact and permeabilized MSCs indicate MRL-MSCs exhibit a greater reliance on and capacity for aerobic metabolism.The greater capacity for oxidative metabolism may provide a protective effect by increasing ATP synthesis per unit substrate and prevent glycolysis-mediated acidosis and subsequent cell death upon transplantation into the glucose-and oxygen-deprived environment of the infarcted heart.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 1N4 Canada ; University of Calgary, KNB Rm 3318. 2500 University Dr. NW, Calgary, Alberta Canada T2N 1N4.

ABSTRACT

Background: Cell-based therapies show promise in repairing cardiac tissue and improving contractile performance following a myocardial infarction. Despite this, ischemia-induced death of transplanted cells remains a major hurdle to the efficacy of treatment. 'Superhealer' MRL/MpJ mesenchymal stem cells (MRL-MSCs) have been reported to exhibit increased engraftment resulting in reduced infarct size and enhanced contractile function. This study determines whether intrinsic differences in mitochondrial oxidative phosphorylation (OXPHOS) assist in explaining the enhanced cellular survival and engraftment of MRL-MSCs.

Findings: Compared to wild type MSCs (WT-MSCs), mitochondria from intact MRL-MSCs exhibited an increase in routine respiration and maximal electron transport capacity by 2.0- and 3.5-fold, respectively. When routine oxygen utilization is expressed as a portion of maximal cellular oxygen flux, the MRL-MSCs have a greater spare respiratory capcity. Additionally, glutamate/malate succinate-supported oxygen consumption in permeabilized cells was elevated approximately 1.25- and 1.4-fold in the MRL-MSCs, respectively.

Conclusion: The results from intact and permeabilized MSCs indicate MRL-MSCs exhibit a greater reliance on and capacity for aerobic metabolism. The greater capacity for oxidative metabolism may provide a protective effect by increasing ATP synthesis per unit substrate and prevent glycolysis-mediated acidosis and subsequent cell death upon transplantation into the glucose-and oxygen-deprived environment of the infarcted heart.

No MeSH data available.


Related in: MedlinePlus

Effects of 48-hour glucose deprivation and ischemia on wild-type mesenchymal stem cell (WT-MSC) and MRL/MpJ mesenchymal stem cell (MRL-MSC) apoptosis. (A) Representative fluorescence-activated cell sorting analysis of apoptotic cells after mitosense red and calcein, AM staining. Healthy, viable MSCs are mitosense red+/calcein, AM+. The mitosense red-/calcein, AM+ MSCs are in the early apoptotic phase, whereas the mitosense red-/calcein, AM+ MSCs are in the late apoptotic/cell death phase. (B) Quantitation of MSC early apoptosis induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM+ MSCs after glucose deprivation and ischemia. (C) Quantitation of MSC late apoptosis/cell death induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM- MSCs after glucose deprivation and ischemia. n = 6-7 independent experiments, data are mean ± S.E.M. *p < 0.05 vs. WT-MSC Control. †p < 0.05 vs. MRL-MSC Control. ¶p < 0.05 vs. WT-MSC of identical experimental conditions. §p < 0.05 vs. WT-MSC Glucose Deprivation. #p < 0.05 vs. MRL-MSC Glucose Deprivation.
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Fig3: Effects of 48-hour glucose deprivation and ischemia on wild-type mesenchymal stem cell (WT-MSC) and MRL/MpJ mesenchymal stem cell (MRL-MSC) apoptosis. (A) Representative fluorescence-activated cell sorting analysis of apoptotic cells after mitosense red and calcein, AM staining. Healthy, viable MSCs are mitosense red+/calcein, AM+. The mitosense red-/calcein, AM+ MSCs are in the early apoptotic phase, whereas the mitosense red-/calcein, AM+ MSCs are in the late apoptotic/cell death phase. (B) Quantitation of MSC early apoptosis induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM+ MSCs after glucose deprivation and ischemia. (C) Quantitation of MSC late apoptosis/cell death induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM- MSCs after glucose deprivation and ischemia. n = 6-7 independent experiments, data are mean ± S.E.M. *p < 0.05 vs. WT-MSC Control. †p < 0.05 vs. MRL-MSC Control. ¶p < 0.05 vs. WT-MSC of identical experimental conditions. §p < 0.05 vs. WT-MSC Glucose Deprivation. #p < 0.05 vs. MRL-MSC Glucose Deprivation.

Mentions: Manipulation of culture conditions to simulate 48 hr glucose deprivation exhibit a clear induction of early apoptosis defined by mitochondrial membrane potential impairment (Figure 3A & B). WT-MSCs under glucose deprivation-only conditions for 48 hr resulted in a drastic increase in early apoptosis (43.61 ± 7.59% vs. 2.57 ± 0.69%; Figure 3B). The effect of glucose deprivation on MRL-MSCs also resulted in an increased percentage of cells undergoing early apoptosis (8.02 ± 1.37% vs. 1.16 ± 0.69%; Figure 3B). However, the proportion of mitochondrial membrane impaired MRL-MSCs was significantly lower than that of WT-MSCs following glucose deprivation (8.02 ± 1.37% vs. 43.61 ± 7.59%; Figure 3B). Interestingly, ischemic culture conditions did not promote significant increases in early apoptotic WT-MSCs or MRL-MSCs compared to control MSCs (Figure 3B). Furthermore, the reduced oxygen availability may have provided a mitochondrial protective effect in the presence of glucose deprivation as the WT-MSCs (43.61 ± 7.59% vs. 6.29 ± 2.55%; Figure 3B) and MRL-MSCs (8.02 ± 1.37% vs. 1.11 ± 0.47%; Figure 3B) exhibited elevated early apoptosis in the glucose-deprived condition compared to the ischemic condition.Figure 3


Increased oxygen consumption and OXPHOS potential in superhealer mesenchymal stem cells.

Hughey CC, Alfaro MP, Belke DD, Rottman JN, Young PP, Wasserman DH, Shearer J - Cell Regen (Lond) (2012)

Effects of 48-hour glucose deprivation and ischemia on wild-type mesenchymal stem cell (WT-MSC) and MRL/MpJ mesenchymal stem cell (MRL-MSC) apoptosis. (A) Representative fluorescence-activated cell sorting analysis of apoptotic cells after mitosense red and calcein, AM staining. Healthy, viable MSCs are mitosense red+/calcein, AM+. The mitosense red-/calcein, AM+ MSCs are in the early apoptotic phase, whereas the mitosense red-/calcein, AM+ MSCs are in the late apoptotic/cell death phase. (B) Quantitation of MSC early apoptosis induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM+ MSCs after glucose deprivation and ischemia. (C) Quantitation of MSC late apoptosis/cell death induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM- MSCs after glucose deprivation and ischemia. n = 6-7 independent experiments, data are mean ± S.E.M. *p < 0.05 vs. WT-MSC Control. †p < 0.05 vs. MRL-MSC Control. ¶p < 0.05 vs. WT-MSC of identical experimental conditions. §p < 0.05 vs. WT-MSC Glucose Deprivation. #p < 0.05 vs. MRL-MSC Glucose Deprivation.
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Fig3: Effects of 48-hour glucose deprivation and ischemia on wild-type mesenchymal stem cell (WT-MSC) and MRL/MpJ mesenchymal stem cell (MRL-MSC) apoptosis. (A) Representative fluorescence-activated cell sorting analysis of apoptotic cells after mitosense red and calcein, AM staining. Healthy, viable MSCs are mitosense red+/calcein, AM+. The mitosense red-/calcein, AM+ MSCs are in the early apoptotic phase, whereas the mitosense red-/calcein, AM+ MSCs are in the late apoptotic/cell death phase. (B) Quantitation of MSC early apoptosis induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM+ MSCs after glucose deprivation and ischemia. (C) Quantitation of MSC late apoptosis/cell death induced by 48 hr glucose deprivation and ischemia with mitosense red and calcein, AM staining. The graph shows the percentage of all MSCs that are mitosense red-/calcein, AM- MSCs after glucose deprivation and ischemia. n = 6-7 independent experiments, data are mean ± S.E.M. *p < 0.05 vs. WT-MSC Control. †p < 0.05 vs. MRL-MSC Control. ¶p < 0.05 vs. WT-MSC of identical experimental conditions. §p < 0.05 vs. WT-MSC Glucose Deprivation. #p < 0.05 vs. MRL-MSC Glucose Deprivation.
Mentions: Manipulation of culture conditions to simulate 48 hr glucose deprivation exhibit a clear induction of early apoptosis defined by mitochondrial membrane potential impairment (Figure 3A & B). WT-MSCs under glucose deprivation-only conditions for 48 hr resulted in a drastic increase in early apoptosis (43.61 ± 7.59% vs. 2.57 ± 0.69%; Figure 3B). The effect of glucose deprivation on MRL-MSCs also resulted in an increased percentage of cells undergoing early apoptosis (8.02 ± 1.37% vs. 1.16 ± 0.69%; Figure 3B). However, the proportion of mitochondrial membrane impaired MRL-MSCs was significantly lower than that of WT-MSCs following glucose deprivation (8.02 ± 1.37% vs. 43.61 ± 7.59%; Figure 3B). Interestingly, ischemic culture conditions did not promote significant increases in early apoptotic WT-MSCs or MRL-MSCs compared to control MSCs (Figure 3B). Furthermore, the reduced oxygen availability may have provided a mitochondrial protective effect in the presence of glucose deprivation as the WT-MSCs (43.61 ± 7.59% vs. 6.29 ± 2.55%; Figure 3B) and MRL-MSCs (8.02 ± 1.37% vs. 1.11 ± 0.47%; Figure 3B) exhibited elevated early apoptosis in the glucose-deprived condition compared to the ischemic condition.Figure 3

Bottom Line: Additionally, glutamate/malate succinate-supported oxygen consumption in permeabilized cells was elevated approximately 1.25- and 1.4-fold in the MRL-MSCs, respectively.The results from intact and permeabilized MSCs indicate MRL-MSCs exhibit a greater reliance on and capacity for aerobic metabolism.The greater capacity for oxidative metabolism may provide a protective effect by increasing ATP synthesis per unit substrate and prevent glycolysis-mediated acidosis and subsequent cell death upon transplantation into the glucose-and oxygen-deprived environment of the infarcted heart.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Calgary, Calgary, AB T2N 1N4 Canada ; University of Calgary, KNB Rm 3318. 2500 University Dr. NW, Calgary, Alberta Canada T2N 1N4.

ABSTRACT

Background: Cell-based therapies show promise in repairing cardiac tissue and improving contractile performance following a myocardial infarction. Despite this, ischemia-induced death of transplanted cells remains a major hurdle to the efficacy of treatment. 'Superhealer' MRL/MpJ mesenchymal stem cells (MRL-MSCs) have been reported to exhibit increased engraftment resulting in reduced infarct size and enhanced contractile function. This study determines whether intrinsic differences in mitochondrial oxidative phosphorylation (OXPHOS) assist in explaining the enhanced cellular survival and engraftment of MRL-MSCs.

Findings: Compared to wild type MSCs (WT-MSCs), mitochondria from intact MRL-MSCs exhibited an increase in routine respiration and maximal electron transport capacity by 2.0- and 3.5-fold, respectively. When routine oxygen utilization is expressed as a portion of maximal cellular oxygen flux, the MRL-MSCs have a greater spare respiratory capcity. Additionally, glutamate/malate succinate-supported oxygen consumption in permeabilized cells was elevated approximately 1.25- and 1.4-fold in the MRL-MSCs, respectively.

Conclusion: The results from intact and permeabilized MSCs indicate MRL-MSCs exhibit a greater reliance on and capacity for aerobic metabolism. The greater capacity for oxidative metabolism may provide a protective effect by increasing ATP synthesis per unit substrate and prevent glycolysis-mediated acidosis and subsequent cell death upon transplantation into the glucose-and oxygen-deprived environment of the infarcted heart.

No MeSH data available.


Related in: MedlinePlus