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| Author(s): |
Ana Carolina Marques
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas |
| Defense date: | 2014-02-26 |
| Examining board members: |
Anibal Eugenio Vercesi;
Nelci Fenalti Höehr;
Gilberto Eiji Shiguemoto
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| Advisor: | Helena Coutinho Franco de Oliveira; Anibal Eugenio Vercesi |
| Abstract | |
Hypercholesterolemic LDL receptor knockout mice (LDLr-/-) from Jackson Laboratory are valuable experimental models to study atherosclerosis development. These mice exhibit high rates of lipogenesis, a process that consumes large amounts of NADPH. It was recently discovered that the mice strain used to produce the LDLr-/- also carries a homozygous NADP-transhydrogenase (NNT) mutation. Loss of NNT may cause oxidative stress due to a poor supply of mitochondrial NADPH. The objective of this study was to investigate the role of elevated lipogenesis and NNT deficiency on the mitochondrial redox status and susceptibility to mitochondrial permeability transition (MPT). Three mice strains were compared: LDLr-/- mice (deficient of both LDL receptor and NTT), C57BL6/J (deficient in NNT only) and the wild type control mice C57BL6/JUnib. We evaluated the mitochondrial respiratory control (oxygen consumption), the NAD(P) redox status (fluorimetry), the susceptibility to calcium induced mitochondrial permeability transition (swelling and dissipation of membrane potential (??) sensitive to cyclosporin A) and the generation of H2O2 (Amplex red®) in isolated heart and liver mitochondria. We observed no significant differences in mitochondrial respiratory parameters in both tissues of the three mice strains studied. As expected, the mitochondria of LDLr-/- and C57BL6/J mice cannot maintain the NADP in the reduced state in vitro, since they are deficient in NNT. Regarding the susceptibility to MPT, we observed significant differences among mitochondria from the 3 strains, as follows: LDLr-/- > C57BL6/J > C57BL6/JUnib (control) in isolated liver mitochondria (swelling and potential dissipation) and in heart mitochondria potential dissipation). Furthermore, the production of H2O2 by the liver mitochondria followed the same MPT pattern: LDLr-/- > C57BL6/J > C57BL6/JUnib (control). Together, these results indicated that the greater susceptibility of LDLr-/- mitochondria to MPT is correlated with decreased NADPH which is explained by both increased consumption (due to high lipogenesis) and decreased production (deficiency NNT) (AU) | |
| FAPESP's process: | 11/15103-4 - IS THE OXIDIZED STATE OF MITOCHONDRIAL NADP IN HYPERCHOLESTEROLEMIC MICE DUE TO INCREASED CHOLESTEROL SYNTHESIS OR TO NADP-TRANSIDROGENASE DEFICIENCY? |
| Grantee: | Ana Carolina Marques |
| Support Opportunities: | Scholarships in Brazil - Master |