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Mitochondrial rejuvenation after induced pluripotency.

Suhr ST, Chang EA, Tjong J, Alcasid N, Perkins GA, Goissis MD, Ellisman MH, Perez GI, Cibelli JB - PLoS ONE (2010)

Bottom Line: Mitochondrial activity is low to minimize generation of DNA-damaging reactive oxygen species during pre-implantation development and increases following implantation and differentiation to meet higher metabolic demands.We have examined the properties of mitochondria in two fibroblast lines, corresponding IPSCs, and fibroblasts re-derived from IPSCs using biochemical methods and electron microscopy, and found a dramatic improvement in the quality and function of the mitochondrial complement of the re-derived fibroblasts compared to input fibroblasts.These results - coupled with earlier data from our laboratory - suggest that IPSC conversion not only resets the "biological clock", but can also rejuvenate the energetic capacity of derived cells.

View Article: PubMed Central - PubMed

Affiliation: Cellular Reprogramming Laboratory, Michigan State University, East Lansing, Michigan, USA.

ABSTRACT

Background: As stem cells of the early embryo mature and differentiate into all tissues, the mitochondrial complement undergoes dramatic functional improvement. Mitochondrial activity is low to minimize generation of DNA-damaging reactive oxygen species during pre-implantation development and increases following implantation and differentiation to meet higher metabolic demands. It has recently been reported that when the stem cell type known as induced pluripotent stem cells (IPSCs) are re-differentiated for several weeks in vitro, the mitochondrial complement progressively re-acquires properties approximating input fibroblasts, suggesting that despite the observation that IPSC conversion "resets" some parameters of cellular aging such as telomere length, it may have little impact on other age-affected cellular systems such as mitochondria in IPSC-derived cells.

Methodology/principal findings: We have examined the properties of mitochondria in two fibroblast lines, corresponding IPSCs, and fibroblasts re-derived from IPSCs using biochemical methods and electron microscopy, and found a dramatic improvement in the quality and function of the mitochondrial complement of the re-derived fibroblasts compared to input fibroblasts. This observation likely stems from two aspects of our experimental design: 1) that the input cell lines used were of advanced cellular age and contained an inefficient mitochondrial complement, and 2) the re-derived fibroblasts were produced using an extensive differentiation regimen that may more closely mimic the degree of growth and maturation found in a developing mammal.

Conclusions/significance: These results - coupled with earlier data from our laboratory - suggest that IPSC conversion not only resets the "biological clock", but can also rejuvenate the energetic capacity of derived cells.

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Related in: MedlinePlus

Analysis of mitochondrial membrane potential in FIB, IPSC, TER and ESCs.A) Representative scatter plots from flow cytometry analysis showing red/green JC1 dye fluorescence in cell types as labeled. The outlined area R4 is red fluorescence and area R3 is green fluorescence. B) Bar graph showing the ratio of JC-1 red and green (R/G) fluorescence indicative of mitochondrial membrane potential for each cell type. Error bars indicate SEM. Letters above individual bars indicate values that differ statistically (P<0.05) from other cell type(s). (FIB = F, IPS = I, TER = T, ESC = E).
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pone-0014095-g003: Analysis of mitochondrial membrane potential in FIB, IPSC, TER and ESCs.A) Representative scatter plots from flow cytometry analysis showing red/green JC1 dye fluorescence in cell types as labeled. The outlined area R4 is red fluorescence and area R3 is green fluorescence. B) Bar graph showing the ratio of JC-1 red and green (R/G) fluorescence indicative of mitochondrial membrane potential for each cell type. Error bars indicate SEM. Letters above individual bars indicate values that differ statistically (P<0.05) from other cell type(s). (FIB = F, IPS = I, TER = T, ESC = E).

Mentions: Mitochondrial membrane potentials of all cell types were analyzed using flow cytometry and the vital dye JC-1[24] to further study the mitochondrial complement. These analyses shown in representative scatter plots in Figure 3A, indicate at a glance that TER cells displayed a dramatic and significant shift in the ratio of red-to-green differential fluorescence. Mitochondria with high membrane potential and a more active electron transport chain efficiently imported the JC-1 dye resulting in aggregation and red JC-1 fluorescence (delineated as region 4(R4) in the plots in Fig. 3A), whereas in less active mitochondria with lower membrane potential, the JC-1 remains in the monomeric, green-fluorescent conformation (region R3 in Fig. 3A). Quantification of the relative ratios are shown in Fig. 3B. Whereas FIB, IPSC, and ESC lines displayed R/G ratios between 1.1–1.9, the TER lines displayed an average R/G ratio of 41.8. This further indicated that the TER cell mitochondrial complement differed significantly from the input parental fibroblasts as well as the pluripotent cell types.


Mitochondrial rejuvenation after induced pluripotency.

Suhr ST, Chang EA, Tjong J, Alcasid N, Perkins GA, Goissis MD, Ellisman MH, Perez GI, Cibelli JB - PLoS ONE (2010)

Analysis of mitochondrial membrane potential in FIB, IPSC, TER and ESCs.A) Representative scatter plots from flow cytometry analysis showing red/green JC1 dye fluorescence in cell types as labeled. The outlined area R4 is red fluorescence and area R3 is green fluorescence. B) Bar graph showing the ratio of JC-1 red and green (R/G) fluorescence indicative of mitochondrial membrane potential for each cell type. Error bars indicate SEM. Letters above individual bars indicate values that differ statistically (P<0.05) from other cell type(s). (FIB = F, IPS = I, TER = T, ESC = E).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991355&req=5

pone-0014095-g003: Analysis of mitochondrial membrane potential in FIB, IPSC, TER and ESCs.A) Representative scatter plots from flow cytometry analysis showing red/green JC1 dye fluorescence in cell types as labeled. The outlined area R4 is red fluorescence and area R3 is green fluorescence. B) Bar graph showing the ratio of JC-1 red and green (R/G) fluorescence indicative of mitochondrial membrane potential for each cell type. Error bars indicate SEM. Letters above individual bars indicate values that differ statistically (P<0.05) from other cell type(s). (FIB = F, IPS = I, TER = T, ESC = E).
Mentions: Mitochondrial membrane potentials of all cell types were analyzed using flow cytometry and the vital dye JC-1[24] to further study the mitochondrial complement. These analyses shown in representative scatter plots in Figure 3A, indicate at a glance that TER cells displayed a dramatic and significant shift in the ratio of red-to-green differential fluorescence. Mitochondria with high membrane potential and a more active electron transport chain efficiently imported the JC-1 dye resulting in aggregation and red JC-1 fluorescence (delineated as region 4(R4) in the plots in Fig. 3A), whereas in less active mitochondria with lower membrane potential, the JC-1 remains in the monomeric, green-fluorescent conformation (region R3 in Fig. 3A). Quantification of the relative ratios are shown in Fig. 3B. Whereas FIB, IPSC, and ESC lines displayed R/G ratios between 1.1–1.9, the TER lines displayed an average R/G ratio of 41.8. This further indicated that the TER cell mitochondrial complement differed significantly from the input parental fibroblasts as well as the pluripotent cell types.

Bottom Line: Mitochondrial activity is low to minimize generation of DNA-damaging reactive oxygen species during pre-implantation development and increases following implantation and differentiation to meet higher metabolic demands.We have examined the properties of mitochondria in two fibroblast lines, corresponding IPSCs, and fibroblasts re-derived from IPSCs using biochemical methods and electron microscopy, and found a dramatic improvement in the quality and function of the mitochondrial complement of the re-derived fibroblasts compared to input fibroblasts.These results - coupled with earlier data from our laboratory - suggest that IPSC conversion not only resets the "biological clock", but can also rejuvenate the energetic capacity of derived cells.

View Article: PubMed Central - PubMed

Affiliation: Cellular Reprogramming Laboratory, Michigan State University, East Lansing, Michigan, USA.

ABSTRACT

Background: As stem cells of the early embryo mature and differentiate into all tissues, the mitochondrial complement undergoes dramatic functional improvement. Mitochondrial activity is low to minimize generation of DNA-damaging reactive oxygen species during pre-implantation development and increases following implantation and differentiation to meet higher metabolic demands. It has recently been reported that when the stem cell type known as induced pluripotent stem cells (IPSCs) are re-differentiated for several weeks in vitro, the mitochondrial complement progressively re-acquires properties approximating input fibroblasts, suggesting that despite the observation that IPSC conversion "resets" some parameters of cellular aging such as telomere length, it may have little impact on other age-affected cellular systems such as mitochondria in IPSC-derived cells.

Methodology/principal findings: We have examined the properties of mitochondria in two fibroblast lines, corresponding IPSCs, and fibroblasts re-derived from IPSCs using biochemical methods and electron microscopy, and found a dramatic improvement in the quality and function of the mitochondrial complement of the re-derived fibroblasts compared to input fibroblasts. This observation likely stems from two aspects of our experimental design: 1) that the input cell lines used were of advanced cellular age and contained an inefficient mitochondrial complement, and 2) the re-derived fibroblasts were produced using an extensive differentiation regimen that may more closely mimic the degree of growth and maturation found in a developing mammal.

Conclusions/significance: These results - coupled with earlier data from our laboratory - suggest that IPSC conversion not only resets the "biological clock", but can also rejuvenate the energetic capacity of derived cells.

Show MeSH
Related in: MedlinePlus