Carnitine O-palmitoyltransferase 1, liver isoform (EC 220.127.116.11) (CPT1-L) (Carnitine O-palmitoyltransferase I, liver isoform) (CPT I) (CPTI-L) (Carnitine palmitoyltransferase 1A) [CPT1]
Human placenta-derived mesenchymal stem cells (PD-MSCs) are powerful sources for cell therapy in regenerative medicine. However, a limited lifespan by senescence through mechanisms that are well unknown is the greatest obstacle. In the present study, we first demonstrated the characterization of replicative senescent PD-MSCs and their possible mitochondrial functional alterations. Human PD-MSCs were cultured to senescent cells for a long period of time. The cells of before passage number 8 were early cells and after passage number 14 were late cells. Also, immortalized cells of PD-MSCs (overexpressed hTERT gene into PD-MSCs) after passage number 14 were positive control of non-senescent cells. The characterization and mitochondria analysis of PD-MSCs were explored with long-term cultivation. Long-term cultivation of PD-MSCs exhibited increases of senescent markers such as SA-β-gal and p21 including apoptotic factor, and decreases of proliferation, differentiation potential, and survival factor. Mitochondrial dysfunction was also observed in membrane potential and metabolic flexibility with enlarged mitochondrial mass. Interestingly, we founded that fatty acid oxidation (FAO) is an important metabolism in PD-MSCs, and carnitine palmitoyltransferase1A (CPT1A) overexpressed in senescent PD-MSCs. The inhibition of CPT1A induced a change of energy metabolism and reversed senescence of PD-MSCs. These findings suggest that alteration of FAO by increased CPT1A plays an important role in mitochondrial dysfunction and senescence of PD-MSCs during long-term cultivation.
- Fatty acid
- Placenta-derived mesenchymal stem cell
Aging affects oxidative metabolism in liver and other tissues. Carnitine acyltransferases are key enzymes of this process in mitochondria. As previously shown, the rate of transcription and activity of carnitine palmitoyltransferase CPT1 are also related to carnitine levels. In this study we compared the effect of dietary l-carnitine (100 mg l-carnitine/kg body weight/day over 3 months) on liver enzymes of aged rats (months 21-24) to adult animals (months 6-9) and age-related controls for both groups. The transcription rate of CPT1, CPT2, and carnitine acetyltransferase (CRAT) was determined by quantitative reverse transcription real-time PCR (RTQPCR) and compared to the activity of the CPT1A enzyme. The results showed that the transcription rates of CPT1, CPT2, and CRAT were similar in aged and adult control animals. Carnitine-fed old rats had a significant (p<0.05) 8-12-fold higher mean transcription rate of CPT1 and CRAT compared to aged controls, adult carnitine-fed animals, and adult controls, whereas the transcription rate of CPT2 was stimulated 2-3-fold in carnitine-fed animals of both age groups. With regard to the enzymatic activity of CPT1 there was a 1.5-fold increase in the old carnitine group compared to all other groups. RNA in situ hybridization also indicated an enhanced expression of CPT1A in hepatocytes from l-carnitine-supplemented animals. These results suggest that l-carnitine stimulates transcription of CPT1, CPT2, and CRAT as well as the enzyme activity of CPT1 in the livers of aged rats.
- Carnitine O-Acetyltransferase
- Carnitine O-Palmitoyltransferase
- Dietary Supplements
- Enzyme Activation
- In Situ Hybridization, Fluorescence
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription, Genetic