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- Canaider, S., et al.
(författare)
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Human Stem Cell Exposure to Developmental Stage Zebrafish Extracts : a Novel Strategy for Tuning Stemness and Senescence Patterning
- 2014
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Ingår i: Cell. - 2329-7042. ; 2:5
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Tidskriftsartikel (refereegranskat)abstract
- Background: Zebrafish exhibits extraordinary ability for tissue regeneration. Despite growing investigations dissecting the molecular underpinning of such regenerative potential, little is known about the possibility to use the chemical inventory of the zebrafishembryo to modulate human stem cell dynamics.Methods: Extracts from zebrafish embryo were collected at different developmental stages, referred to as ZF1, ZF2, ZF3 (early stages), and ZF4, ZF5 (late stages). Human adipose-derived stem cells (hASCs), isolated from microfractured fat tissue obtained with a novel non-enzymatic method (Lipogems), were cultured in absence or presence of each developmental stage extract. Cell viability was assessed by MTT assay. Nuclear morphology was investigated by cell-permeable dye 4’,6-DAPI. Caspase-3 activity was assessed by ELISA. Gene transcription was monitored by real-time PCR.Results: Late developmental stage extracts decreased cell viability and elicited caspase-3 mediated apoptosis. This effect did not involve Bax or Bcl-2 transcription. Conversely, early developmental stage ZF1 did not affect cell viability or apoptosis, albeit increasing Bax/Bcl-2mRNA ratio. ZF1 enhanced transcription of the stemness/pluripotency genes Oct-4, Sox-2and c-Myc. ZF1 also induced the transcription of TERT, encoding the catalytic subunit of telomerase, as well as the gene expression of Bmi-1, a chromatin remodeler acting as a major telomerase-independent repressor of senescence. These transcriptional responses were restricted to the action of early stage factors, since they were not elicited by late developmental stage ZF5.Conclusions: Exposure to early developmental stage zebrafish embryo extracts may enhance stem cell expression of multipotency and activate both telomerase-dependent and -independent antagonists of cell senescence. These outcomes may prove rewarding during prolonged expansion in culture, as it occurs in most cell therapy protocols.
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| 2. |
- Ponsot, Elodie, 1973-, et al.
(författare)
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Mitochondrial tissue specificity of substrates utilization in rat cardiac and skeletal muscles
- 2005
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Ingår i: Journal of Cellular Physiology. - Hoboken, USA : John Wiley & Sons. - 0021-9541 .- 1097-4652. ; 203:3, s. 479-86
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Tidskriftsartikel (refereegranskat)abstract
- As energetic metabolism is crucial for muscles, they develop different adaptations to respond to fluctuating demand among muscle types. Whereas quantitative characteristics are known, no study described simultaneously quantitative and qualitative differences among muscle types in terms of substrates utilization patterns. This study thus defined the pattern of substrates preferential utilization by mitochondria from glycolytic gastrocnemius (GAS) and oxidative soleus (SOL) skeletal muscles and from heart left ventrical (LV) in rats. We measured in situ, ADP (2 mM)-stimulated, mitochondrial respiration rates from skinned fibers in presence of increasing concentrations of pyruvate (Pyr) + malate (Mal), palmitoyl-carnitine (Palm-C) + Mal, glutamate (Glut) + Mal, glycerol-3-phosphate (G3-P), lactate (Lact) + Mal. Because the fibers oxygen uptake (Vs) followed Michaelis-Menten kinetics in function of substrates level we determined the Vs and Km, representing maximal oxidative capacity and the mitochondrial sensibility for each substrate, respectively. Vs were in the order GAS < SOL < LV for Pyr, Glu, and Palm-C substrates, whereas in the order SOL = LV < GAS with G3-P. Moreover, the relative capacity to oxidize Palm-C is extremely higher in LV than in SOL. Vs was not stimulated by the Lact substrate. The Km was equal for Pyr among muscles, but much lower for G3-P in GAS and lower for Palm-C in LV. These results demonstrate qualitative mitochondrial tissue specificity for metabolic pathways. Mitochondria of glycolytic muscle fibers are well adapted to play a central role for maintaining a satisfactory cytosolic redox state in these fibers, whereas mitochondria of LV developed important capacities to use fatty acids.
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