Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2007 Apr;82(2):210-9.
doi: 10.1016/j.yexmp.2006.12.004. Epub 2006 Dec 28.

Increased oxidative stress is associated with balanced increases in hepatocyte apoptosis and proliferation in glycerol-3-phosphate acyltransferase-1 deficient mice

Linda E Hammond  1 , Craig D Albright, Lihua He, Ivan Rusyn, Steven M Watkins, Scott D Doughman, John J Lemasters, Rosalind A Coleman
Affiliations

Increased oxidative stress is associated with balanced increases in hepatocyte apoptosis and proliferation in glycerol-3-phosphate acyltransferase-1 deficient mice

Linda E Hammond et al. Exp Mol Pathol. 2007 Apr.

Abstract

The absence of mouse mitochondrial glycerol-3-phosphate acyltransferase-1 (Gpat1-/-) increases the amount of arachidonate in liver phospholipids and increases beta-hydroxybutyrate and acyl-carnitines, suggesting an elevated rate of liver fatty acid oxidation. We asked whether these alterations might increase reactive oxygen species (ROS), apoptosis, or hepatocyte proliferation. Compared to wildtype controls, liver mitochondria from Gpat1-/- mice showed a 20% increase in the rate of ROS production and a markedly increased sensitivity to the induction of the mitochondrial permeability transition. Mitochondrial phosphatidylethanolamine and phosphatidylcholine from Gpat1-/- liver contained 21% and 67% more arachidonate, respectively, than wildtype controls, and higher amounts of 4-hydroxynonenal, a product of arachidonate peroxidation. Oxidative stress was associated with an increase in apoptosis, and with 3-fold and 15-fold higher TUNEL positive cells in liver from young and old Gpat1-/- mice, respectively, compared to age-matched controls. Compared to controls, bromodeoxyuridine labeling was 50% and 7-fold higher in livers from young and old Gpat1-/- mice, respectively, but fewer glutathione-S-transferase positive cells were present. Thus, Gpat1-/- liver exhibits increased oxidative stress and sensitivity of the mitochondrial permeability transition pore, and a balanced increase in apoptosis and proliferation.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Immunoreactivity for 4-hydroxy-2-nonenal is increased in Gpat1-/- mice. Representative liver sections from 2-4 mo old (young) and 12-18 mo old (old) mice were probed with an antibody that recognizes 4-HNE. Levels of 4-HNE immunoreactivity were measured as described in the Materials and Methods. Increased levels of 4-HNE were found in Gpat1-/- livers in both age groups. Data are shown as means ± standard error for 4 mice per group. Columns identified with different letters differ significantly from each other (P < 0.01, ANOVA with Sheffe’s test).
Figure 2
Figure 2
Liver mitochondrial phospholipid fatty acid composition is altered in Gpat1-/- mice. Liver mitochondrial phospholipid species from 2 mo old Gpat1-/- (n=4) and wildtype (n=5) were quantified as described in Materials and Methods. Only major fatty acids are presented. A) Selected PE fatty acids. B) PE fatty acid classes. C) Selected PC fatty acids. D) PC fatty acid classes. E) Selected PS fatty acids. F) PS fatty acid classes. G) Selected CL fatty acids. H) CL fatty acid classes. Data are shown as means ± standard error. Statistical significance was determined by Student’s t-test, * P< 0.05, ** P< 0.005, *** P< 0.001. Abbreviations: PE, phosphatidylethanolamine; PC, phosphatidylcholine; PS, phosphatidylserine; CL, cardiolipin; SFA, saturated fatty acid; MUFA, monounsaturated fatty acid; MPT, mitochondrial permeability transition pore; PUFA, polyunsaturated fatty acid.
Figure 3
Figure 3
Liver mitochondria from Gpat1-/- mice have normal morphology. Representative electron microscopy images of liver mitochondria from 2 mo old Gpat1-/- and wildtype mice.
Figure 4
Figure 4
Liver mitochondria from Gpat1-/- mice are more sensitive to Ca2+-induced mitochondrial permeability transition. Liver mitochondria (0.5 mg of protein/ml) from 2 mo old Gpat1-/- and wildtype mice were incubated in MPT buffer containing 1 μM TMRM and 1 μM Fluo-5N in 48-well microtiter plates. A) Absorbance change at 620 nm, B) TMRM fluorescence excited at 544 nm, and C) Fluo-5N excited at 485 nm were measured using fluorescence plate reader, as described in Materials and Methods. CaCl2 at 100 μM was added (arrow) after an initial 2 min baseline measurement. A representative experiment is shown (n=4). AU, arbitrary units.
Figure 5
Figure 5
Apoptosis and BrdU labeling are increased in liver from Gpat1-/- mice. A) Representative liver slices were examined using a TUNEL assay as described in the Materials and Methods. Increased numbers of TUNEL-positive cells were found in Gpat1-/- liver sections from 2-4 mo old (young) and 12-18 mo old (old) mice compared to wildtype mice of the same ages. B) Liver slices were analyzed for the incorporation of BrdU as described in Materials and Methods. Increased numbers of BrdU labeled cells were found in Gpat1-/- liver sections from 2 mo old (young) and 12-18 mo old (old) mice compared to wildtype mice of the same ages. Data are shown as means ± standard error; columns identified with different letters differ significantly from each other (P < 0.01, ANOVA with Scheffe’s test).
Figure 6
Figure 6
Glutathione S-transferase placental form is decreased in Gpat1-/- mice. Representative liver slices from 12-18 mo old mice were probed with an antibody that recognizes glutathione S-transferase placental form (GST-P) and the levels of GST-P immunoreactivity were measured as described in the Materials and Methods. Data are shown as means ± standard error. Decreased levels of GST-P were found in Gpat1-/- (P < 0.001; Student’s t-test).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Albright CD, da Costa KA, Craciunescu CN, Klem E, Mar MH, Zeisel SH. Regulation of choline deficiency apoptosis by epidermal growth factor in CWSV-1 rat hepatocytes. Cell. Physiol. Biochem. 2005;15:59–68. - PMC - PubMed
    1. Albright CD, Friedrich CB, Brown EC, Mar MH, Zeisel SH. Maternal dietary choline availability alters mitosis, apoptosis and the localization of TOAD-64 protein in the developing fetal rat septum. Brain Res. Dev. Brain Res. 1999;115:123–129. - PubMed
    1. Albright CD, Liu R, Bethea TC, Da Costa KA, Salganik RI, Zeisel SH. Choline deficiency induces apoptosis in SV40-immortalized CWSV-1 rat hepatocytes in culture. FASEB J. 1996;10:510–516. - PubMed
    1. Albright CD, Salganik RI, Van Dyke T. Dietary depletion of vitamin E and vitamin A inhibits mammary tumor growth and metastasis in transgenic mice. J. Nutr. 2004;134:1139–1144. - PubMed
    1. Ameen C, Linden D, Larsson BM, Mode A, Holmang A, Oscarsson J. Effects of gender and GH secretory pattern on sterol regulatory element-binding protein-1c and its target genes in rat liver. Am. J. Physiol. Endocrinol. Metab. 2004;287:E1039–1048. - PubMed

Publication types

MeSH terms

LinkOut - more resources