TY - JOUR

T1 - Stressed-induced TMEM135 protein is part of a conserved genetic network involved in fat storage and longevity regulation in Caenorhabditis elegans

AU - Exil, Vernat J.

AU - Silva Avila, Daiana

AU - Benedetto, Alexandre

AU - Exil, Elizabeth A.

AU - Adams, Margaret R.

AU - Au, Catherine

AU - Aschner, Michael

PY - 2010/12/3

Y1 - 2010/12/3

N2 - Disorders of mitochondrial fat metabolism lead to sudden death in infants and children. Although survival is possible, the underlying molecular mechanisms which enable this outcome have not yet been clearly identified. Here we describe a conserved genetic network linking disorders of mitochondrial fat metabolism in mice to mechanisms of fat storage and survival in Caenorhabditis elegans (C. elegans). We have previously documented a mouse model of mitochondrial very-long chain acyl-CoA dehydrogenase (VLCAD) deficiency. We originally reported that the mice survived birth, but, upon exposure to cold and fasting stresses, these mice developed cardiac dysfunction, which greatly reduced survival. We used cDNA microarrays to outline the induction of several markers of lipid metabolism in the heart at birth in surviving mice. We hypothesized that the induction of fat metabolism genes in the heart at birth is part of a regulatory feedback circuit that plays a critical role in survival. The present study uses a dual approach employing both C57BL/6 mice and the nematode, C. elegans, to focus on TMEM135, a conserved protein which we have found to be upregulated 4.3 (±0.14)-fold in VLCAD-deficient mice at birth. Our studies have demonstrated that TMEM135 is highly expressed in mitochondria and in fat-loaded tissues in the mouse. Further, when fasting and cold stresses were introduced to mice, we observed 3.25 (±0.03)- and 8.2 (±0.31)-fold increases in TMEM135 expression in the heart, respectively. Additionally, we found that deletion of the tmem135 orthologue in C. elegans caused a 41.8% (±2.8%) reduction in fat stores, a reduction in mitochondrial action potential and decreased longevity of the worm. In stark contrast, C. elegans transgenic animals overexpressing TMEM-135 exhibited increased longevity upon exposure to cold stress. Based on these results, we propose that TMEM135 integrates biological processes involving fat metabolism and energy expenditure in both the worm (invertebrates) and in mammalian organisms. The data obtained from our experiments suggest that TMEM135 is part of a regulatory circuit that plays a critical role in the survival of VLCAD-deficient mice and perhaps in other mitochondrial genetic defects of fat metabolism as well.

AB - Disorders of mitochondrial fat metabolism lead to sudden death in infants and children. Although survival is possible, the underlying molecular mechanisms which enable this outcome have not yet been clearly identified. Here we describe a conserved genetic network linking disorders of mitochondrial fat metabolism in mice to mechanisms of fat storage and survival in Caenorhabditis elegans (C. elegans). We have previously documented a mouse model of mitochondrial very-long chain acyl-CoA dehydrogenase (VLCAD) deficiency. We originally reported that the mice survived birth, but, upon exposure to cold and fasting stresses, these mice developed cardiac dysfunction, which greatly reduced survival. We used cDNA microarrays to outline the induction of several markers of lipid metabolism in the heart at birth in surviving mice. We hypothesized that the induction of fat metabolism genes in the heart at birth is part of a regulatory feedback circuit that plays a critical role in survival. The present study uses a dual approach employing both C57BL/6 mice and the nematode, C. elegans, to focus on TMEM135, a conserved protein which we have found to be upregulated 4.3 (±0.14)-fold in VLCAD-deficient mice at birth. Our studies have demonstrated that TMEM135 is highly expressed in mitochondria and in fat-loaded tissues in the mouse. Further, when fasting and cold stresses were introduced to mice, we observed 3.25 (±0.03)- and 8.2 (±0.31)-fold increases in TMEM135 expression in the heart, respectively. Additionally, we found that deletion of the tmem135 orthologue in C. elegans caused a 41.8% (±2.8%) reduction in fat stores, a reduction in mitochondrial action potential and decreased longevity of the worm. In stark contrast, C. elegans transgenic animals overexpressing TMEM-135 exhibited increased longevity upon exposure to cold stress. Based on these results, we propose that TMEM135 integrates biological processes involving fat metabolism and energy expenditure in both the worm (invertebrates) and in mammalian organisms. The data obtained from our experiments suggest that TMEM135 is part of a regulatory circuit that plays a critical role in the survival of VLCAD-deficient mice and perhaps in other mitochondrial genetic defects of fat metabolism as well.

KW - Acyl-CoA Dehydrogenase, Long-Chain

KW - Adipose Tissue

KW - Animals

KW - Antioxidants

KW - Caenorhabditis elegans

KW - Caenorhabditis elegans Proteins

KW - Fatty Acids

KW - Gene Deletion

KW - Gene Expression Regulation

KW - Gene Regulatory Networks

KW - Lipid Metabolism, Inborn Errors

KW - Longevity

KW - Membrane Proteins

KW - Metabolism, Inborn Errors

KW - Mice

KW - Mice, Knockout

KW - Mitochondrial Diseases

KW - Muscular Diseases

KW - Subcellular Fractions

KW - Tissue Distribution

KW - Journal Article

KW - Research Support, N.I.H., Extramural

KW - Research Support, Non-U.S. Gov't

U2 - 10.1371/journal.pone.0014228

DO - 10.1371/journal.pone.0014228

M3 - Journal article

C2 - 21151927

VL - 5

JO - PLoS ONE

JF - PLoS ONE

SN - 1932-6203

IS - 12

M1 - e14228

ER -