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Parmar G, Fong-McMaster C, Pileggi CA, Patten DA, Cuillerier A, Myers S, Wang Y, Hekimi S, Cuperlovic-Culf M, Harper ME. Accessory subunit NDUFB4 participates in mitochondrial complex I supercomplex formation. J Biol Chem 2024; 300:105626. [PMID: 38211818 PMCID: PMC10862015 DOI: 10.1016/j.jbc.2024.105626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/18/2023] [Accepted: 12/21/2023] [Indexed: 01/13/2024] Open
Abstract
Mitochondrial electron transport chain complexes organize into supramolecular structures called respiratory supercomplexes (SCs). The role of respiratory SCs remains largely unconfirmed despite evidence supporting their necessity for mitochondrial respiratory function. The mechanisms underlying the formation of the I1III2IV1 "respirasome" SC are also not fully understood, further limiting insights into these processes in physiology and diseases, including neurodegeneration and metabolic syndromes. NDUFB4 is a complex I accessory subunit that contains residues that interact with the subunit UQCRC1 from complex III, suggesting that NDUFB4 is integral for I1III2IV1 respirasome integrity. Here, we introduced specific point mutations to Asn24 (N24) and Arg30 (R30) residues on NDUFB4 to decipher the role of I1III2-containing respiratory SCs in cellular metabolism while minimizing the functional consequences to complex I assembly. Our results demonstrate that NDUFB4 point mutations N24A and R30A impair I1III2IV1 respirasome assembly and reduce mitochondrial respiratory flux. Steady-state metabolomics also revealed a global decrease in citric acid cycle metabolites, affecting NADH-generating substrates. Taken together, our findings highlight an integral role of NDUFB4 in respirasome assembly and demonstrate the functional significance of SCs in regulating mammalian cell bioenergetics.
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Affiliation(s)
- Gaganvir Parmar
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada
| | - Claire Fong-McMaster
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada
| | - Chantal A Pileggi
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada
| | - David A Patten
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada
| | - Alexanne Cuillerier
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Stephanie Myers
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada
| | - Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Miroslava Cuperlovic-Culf
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada; National Research Council of Canada, Digital Technologies Research Centre, Ottawa, Ontario, Canada
| | - Mary-Ellen Harper
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ontario, Canada.
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Rebelo AP, Tomaselli PJ, Medina J, Wang Y, Dohrn MF, Nyvltova E, Danzi MC, Garrett M, Smith SE, Pestronk A, Li C, Ruiz A, Jacobs E, Feely SME, França MC, Gomes MV, Santos DF, Kumar S, Lombard DB, Saporta M, Hekimi S, Barrientos A, Weihl C, Shy ME, Marques W, Zuchner S. Biallelic variants in COQ7 cause distal hereditary motor neuropathy with upper motor neuron signs. Brain 2023; 146:4191-4199. [PMID: 37170631 PMCID: PMC10545612 DOI: 10.1093/brain/awad158] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 04/12/2023] [Accepted: 04/23/2023] [Indexed: 05/13/2023] Open
Abstract
COQ7 encodes a hydroxylase responsible for the penultimate step of coenzyme Q10 (CoQ10) biosynthesis in mitochondria. CoQ10 is essential for multiple cellular functions, including mitochondrial oxidative phosphorylation, lipid metabolism, and reactive oxygen species homeostasis. Mutations in COQ7 have been previously associated with primary CoQ10 deficiency, a clinically heterogeneous multisystemic mitochondrial disorder. We identified COQ7 biallelic variants in nine families diagnosed with distal hereditary motor neuropathy with upper neuron involvement, expending the clinical phenotype associated with defects in this gene. A recurrent p.Met1? change was identified in five families from Brazil with evidence of a founder effect. Fibroblasts isolated from patients revealed a substantial depletion of COQ7 protein levels, indicating protein instability leading to loss of enzyme function. High-performance liquid chromatography assay showed that fibroblasts from patients had reduced levels of CoQ10, and abnormal accumulation of the biosynthetic precursor DMQ10. Accordingly, fibroblasts from patients displayed significantly decreased oxygen consumption rates in patients, suggesting mitochondrial respiration deficiency. Induced pluripotent stem cell-derived motor neurons from patient fibroblasts showed significantly increased levels of extracellular neurofilament light protein, indicating axonal degeneration. Our findings indicate a molecular pathway involving CoQ10 biosynthesis deficiency and mitochondrial dysfunction in patients with distal hereditary motor neuropathy. Further studies will be important to evaluate the potential benefits of CoQ10 supplementation in the clinical outcome of the disease.
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Affiliation(s)
- Adriana P Rebelo
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
| | - Pedro J Tomaselli
- Department of Neurology, University of São Paulo, Ribeirão Preto, 14048-900, Brazil
| | - Jessica Medina
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
| | - Ying Wang
- Department of Biology, McGill University, Montreal, QC, H3A 1A1, Canada
| | - Maike F Dohrn
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen 52074, Germany
| | - Eva Nyvltova
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Matt C Danzi
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
| | - Mark Garrett
- Department of Neurology, Washington University, St. Louis, MO 63112, USA
| | - Sean E Smith
- Department of Neurology, Washington University, St. Louis, MO 63112, USA
| | - Alan Pestronk
- Department of Neurology, Washington University, St. Louis, MO 63112, USA
| | - Chengcheng Li
- Department of Neurology, Washington University, St. Louis, MO 63112, USA
| | - Ariel Ruiz
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
| | - Elizabeth Jacobs
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
| | - Shawna M E Feely
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Marcondes C França
- Department of Neurology, University of São Paulo, Ribeirão Preto, 14048-900, Brazil
| | - Marcus V Gomes
- Department of Neurology, University of São Paulo, Ribeirão Preto, 14048-900, Brazil
| | - Diogo F Santos
- Department of Neurology, Federal University of Uberlândia, Uberlândia, MG 38405-320, Brazil
| | - Surinder Kumar
- Department of Pathology & Laboratory Medicine, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - David B Lombard
- Department of Pathology & Laboratory Medicine, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Mario Saporta
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, QC, H3A 1A1, Canada
| | - Antoni Barrientos
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Conrad Weihl
- Department of Neurology, Washington University, St. Louis, MO 63112, USA
| | - Michael E Shy
- Department of Neurology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Wilson Marques
- Department of Neurology, University of São Paulo, Ribeirão Preto, 14048-900, Brazil
| | - Stephan Zuchner
- Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL 33136, USA
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Smith IC, Pileggi CA, Wang Y, Kernohan K, Hartley T, McMillan HJ, Sampaio ML, Melkus G, Woulfe J, Parmar G, Bourque PR, Breiner A, Zwicker J, Pringle CE, Jarinova O, Lochmüller H, Dyment DA, Brais B, Boycott KM, Hekimi S, Harper ME, Warman-Chardon J. Novel Homozygous Variant in COQ7in Siblings With Hereditary Motor Neuropathy. Neurol Genet 2023; 9:e200048. [PMID: 37077559 PMCID: PMC10108386 DOI: 10.1212/nxg.0000000000200048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 10/19/2022] [Indexed: 01/26/2023]
Abstract
Background and ObjectivesCoenzyme Q10(CoQ10) is an important electron carrier and antioxidant. The COQ7 enzyme catalyzes the hydroxylation of 5-demethoxyubiquinone-10 (DMQ10), the second-to-last step in the CoQ10biosynthesis pathway. We report a consanguineous family presenting with a hereditary motor neuropathy associated with a homozygous c.1A > G p.? variant ofCOQ7with abnormal CoQ10biosynthesis.MethodsAffected family members underwent clinical assessments that included nerve conduction testing, histologic analysis, and MRI. Pathogenicity of theCOQ7variant was assessed in cultured fibroblasts and skeletal muscle using a combination of immunoblots, respirometry, and quinone analysis.ResultsThree affected siblings, ranging from 12 to 24 years of age, presented with a severe length-dependent motor neuropathy with marked symmetric distal weakness and atrophy with normal sensation. Muscle biopsy of the quadriceps revealed chronic denervation pattern. An MRI examination identified moderate to severe fat infiltration in distal muscles. Exome sequencing demonstrated the homozygousCOQ7c.1A > G p.? variant that is expected to bypass the first 38 amino acid residues at the n-terminus, initiating instead with methionine at position 39. This is predicted to cause the loss of the cleavable mitochondrial targeting sequence and 2 additional amino acids, thereby preventing the incorporation and subsequent folding of COQ7 into the inner mitochondrial membrane. Pathogenicity of theCOQ7variant was demonstrated by diminished COQ7 and CoQ10levels in muscle and fibroblast samples of affected siblings but not in the father, unaffected sibling, or unrelated controls. In addition, fibroblasts from affected siblings had substantial accumulation of DMQ10, and maximal mitochondrial respiration was impaired in both fibroblasts and muscle.DiscussionThis report describes a new neurologic phenotype ofCOQ7-related primary CoQ10deficiency. Novel aspects of the phenotype presented by this family include pure distal motor neuropathy involvement, as well as the lack of upper motor neuron features, cognitive delay, or sensory involvement in comparison with cases ofCOQ7-related CoQ10deficiency previously reported in the literature.
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Affiliation(s)
- Ian C Smith
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Chantal A Pileggi
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Ying Wang
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Kristin Kernohan
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Taila Hartley
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Hugh J McMillan
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Marcos Loreto Sampaio
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Gerd Melkus
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - John Woulfe
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Gaganvir Parmar
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Pierre R Bourque
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Ari Breiner
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Jocelyn Zwicker
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - C Elizabeth Pringle
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Olga Jarinova
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Hanns Lochmüller
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - David A Dyment
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Bernard Brais
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Kym M Boycott
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Siegfried Hekimi
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Mary-Ellen Harper
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
| | - Jodi Warman-Chardon
- The Ottawa Hospital Research Institute (I.C.S., M.L.S., G.M., A.B., J.Z., H.L., J.W.-C.), Ottawa; Department of Biochemistry, Microbiology and Immunology (C.A.P., G.P., M.-E.H.), Faculty of Medicine, University of Ottawa, Ontario; Ottawa Institute of Systems Biology (C.A.P., G.P., M.-E.H.), University of Ottawa, Ontario; Department of Biology (Y.W., S.H.), McGill University, Montreal, Quebec; Children's Hospital of Eastern Ontario Research Institute (K.K., T.H., O.J., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; Newborn Screening Ontario (K.K.), Ottawa; Departments of Pediatrics, Neurology, & Neurosurgery (H.J.M.), Montreal Children's Hospital, McGill University, Montreal, Quebec; Department of Radiology, Radiation Oncology and Medical Physics (M.L.S., G.M.), University of Ottawa, Ontario; Department of Laboratory Medicine (J.W.), The Ottawa Hospital, Ontario; Department of Medicine (Neurology) (P.R.B., A.B., J.Z., E.P., C.E.P., H.L., J.W.-C.), The Ottawa Hospital, Ontario; Faculty of Medicine/Brain and Mind Research Institute (A.B., H.L., D.A.D., K.M.B., J.W.-C.), University of Ottawa, Ontario; and Department of Neurology and Neurosurgery (B.B.), Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada
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4
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Branicky R, Wang Y, Khaki A, Liu JL, Kramer-Drauberg M, Hekimi S. Stimulation of RAS-dependent ROS signaling extends longevity by modulating a developmental program of global gene expression. Sci Adv 2022; 8:eadc9851. [PMID: 36449615 PMCID: PMC9710873 DOI: 10.1126/sciadv.adc9851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 10/14/2022] [Indexed: 06/17/2023]
Abstract
We show that elevation of mitochondrial superoxide generation increases Caenorhabditis elegans life span by enhancing a RAS-dependent ROS (reactive oxygen species) signaling pathway (RDRS) that controls the expression of half of the genome as well as animal composition and physiology. RDRS stimulation mimics a program of change in gene expression that is normally observed at the end of postembryonic development. We further show that RDRS is regulated by negative feedback from the superoxide dismutase 1 (SOD-1)-dependent conversion of superoxide into cytoplasmic hydrogen peroxide, which, in turn, acts on a redox-sensitive cysteine (C118) of RAS. Preventing C118 oxidation by replacement with serine, or mimicking oxidation by replacement with aspartic acid, leads to opposite changes in the expression of the same large set of genes that is affected when RDRS is stimulated by mitochondrial superoxide. The identities of these genes suggest that stimulation of the pathway extends life span by boosting turnover and repair while moderating damage from metabolic activity.
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Haynes CM, Hekimi S. Mitochondrial dysfunction, aging, and the mitochondrial unfolded protein response in Caenorhabditis elegans. Genetics 2022; 222:iyac160. [PMID: 36342845 PMCID: PMC9713405 DOI: 10.1093/genetics/iyac160] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/12/2022] [Indexed: 11/09/2022] Open
Abstract
We review the findings that establish that perturbations of various aspects of mitochondrial function, including oxidative phosphorylation, can promote lifespan extension, with different types of perturbations acting sometimes independently and additively on extending lifespan. We also review the great variety of processes and mechanisms that together form the mitochondrial unfolded protein response. We then explore the relationships between different types of mitochondrial dysfunction-dependent lifespan extension and the mitochondrial unfolded protein response. We conclude that, although several ways that induce extended lifespan through mitochondrial dysfunction require a functional mitochondrial unfolded protein response, there is no clear indication that activation of the mitochondrial unfolded protein response is sufficient to extend lifespan, despite the fact that the mitochondrial unfolded protein response impacts almost every aspect of mitochondrial function. In fact, in some contexts, mitochondrial unfolded protein response activation is deleterious. To explain this pattern, we hypothesize that, although triggered by mitochondrial dysfunction, the lifespan extension observed might not be the result of a change in mitochondrial function.
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Affiliation(s)
- Cole M Haynes
- Molecular, Cell and Cancer Biology, UMass-Chan Medical School, Worcester, MA 01655, USA
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, QC H3A 0G4, Canada
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6
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Wang Y, Hekimi S. The CoQ biosynthetic di-iron carboxylate hydroxylase COQ7 is inhibited by in vivo metalation with manganese but remains functional by metalation with cobalt. MicroPubl Biol 2022; 2022:10.17912/micropub.biology.000635. [PMID: 36176269 PMCID: PMC9513594 DOI: 10.17912/micropub.biology.000635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/30/2022] [Accepted: 09/12/2022] [Indexed: 11/28/2022]
Abstract
Coenzyme Q (CoQ; ubiquinone) is an obligate component of the mitochondrial electron transport chain. COQ7 is a mitochondrial hydroxylase that is required for CoQ biosynthesis. COQ7 belongs to di-iron carboxylate enzymes, a rare type of enzyme that carries out a wide range of reactions. We found that manganese exposure of mouse cells leads to decreased COQ7 activity, but that pre-treatment with cobalt interferes with the inhibition by manganese. Our findings suggest that cobalt has greater affinity for the active site of COQ7 than both iron and manganese and that replacement of iron by cobalt at the active site preserves catalytic activity.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
,
Correspondence to: Siegfried Hekimi (
)
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7
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Wang Y, Hekimi S. The efficacy of coenzyme Q 10 treatment in alleviating the symptoms of primary coenzyme Q 10 deficiency: A systematic review. J Cell Mol Med 2022; 26:4635-4644. [PMID: 35985679 PMCID: PMC9443948 DOI: 10.1111/jcmm.17488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/21/2022] [Accepted: 06/30/2022] [Indexed: 12/31/2022] Open
Abstract
Coenzyme Q10 (CoQ10) is necessary for mitochondrial electron transport. Mutations in CoQ10 biosynthetic genes cause primary CoQ10 deficiency (PCoQD) and manifest as mitochondrial disorders. It is often stated that PCoQD patients can be treated by oral CoQ10 supplementation. To test this, we compiled all studies describing PCoQD patients up to May 2022. We excluded studies with no data on CoQ10 treatment, or with insufficient description of effectiveness. Out of 303 PCoQD patients identified, we retained 89 cases, of which 24 reported improvements after CoQ10 treatment (27.0%). In five cases, the patient's condition was reported to deteriorate after halting of CoQ10 treatment. 12 cases reported improvement in the severity of ataxia and 5 cases in the severity of proteinuria. Only a subjective description of improvement was reported for 4 patients described as responding. All reported responses were partial improvements of only some symptoms. For PCoQD patients, CoQ10 supplementation is replacement therapy. Yet, there is only very weak evidence for the efficacy of the treatment. Our findings, thus, suggest a need for caution when seeking to justify the widespread use of CoQ10 for the treatment of any disease or as dietary supplement.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
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8
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Rossmann MP, Hoi K, Chan V, Abraham BJ, Yang S, Mullahoo J, Papanastasiou M, Wang Y, Elia I, Perlin JR, Hagedorn EJ, Hetzel S, Weigert R, Vyas S, Nag PP, Sullivan LB, Warren CR, Dorjsuren B, Greig EC, Adatto I, Cowan CA, Schreiber SL, Young RA, Meissner A, Haigis MC, Hekimi S, Carr SA, Zon LI. Cell-specific transcriptional control of mitochondrial metabolism by TIF1γ drives erythropoiesis. Science 2021; 372:716-721. [PMID: 33986176 DOI: 10.1126/science.aaz2740] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 03/29/2021] [Indexed: 12/11/2022]
Abstract
Transcription and metabolism both influence cell function, but dedicated transcriptional control of metabolic pathways that regulate cell fate has rarely been defined. We discovered, using a chemical suppressor screen, that inhibition of the pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase (DHODH) rescues erythroid differentiation in bloodless zebrafish moonshine (mon) mutant embryos defective for transcriptional intermediary factor 1 gamma (tif1γ). This rescue depends on the functional link of DHODH to mitochondrial respiration. The transcription elongation factor TIF1γ directly controls coenzyme Q (CoQ) synthesis gene expression. Upon tif1γ loss, CoQ levels are reduced, and a high succinate/α-ketoglutarate ratio leads to increased histone methylation. A CoQ analog rescues mon's bloodless phenotype. These results demonstrate that mitochondrial metabolism is a key output of a lineage transcription factor that drives cell fate decisions in the early blood lineage.
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Affiliation(s)
- Marlies P Rossmann
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karen Hoi
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Victoria Chan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Brian J Abraham
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Song Yang
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - James Mullahoo
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | | | - Ying Wang
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada
| | - Ilaria Elia
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Julie R Perlin
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Elliott J Hagedorn
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Sara Hetzel
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Raha Weigert
- Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Sejal Vyas
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Partha P Nag
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Lucas B Sullivan
- Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Curtis R Warren
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Bilguujin Dorjsuren
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Eugenia Custo Greig
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Isaac Adatto
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Chad A Cowan
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | | | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alexander Meissner
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA.,Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.,Department of Genome Regulation, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Marcia C Haigis
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada
| | - Steven A Carr
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Leonard I Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA. .,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
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Wang Y, Hekimi S. Micellization of coenzyme Q by the fungicide caspofungin allows for safe intravenous administration to reach extreme supraphysiological concentrations. Redox Biol 2020; 36:101680. [PMID: 32810741 PMCID: PMC7451649 DOI: 10.1016/j.redox.2020.101680] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022] Open
Abstract
Coenzyme Q10 (CoQ10; also known as ubiquinone) is a vital, redox-active membrane component that functions as obligate electron transporter in the mitochondrial respiratory chain, as cofactor in other enzymatic processes and as antioxidant. CoQ10 supplementation has been widely investigated for treating a variety of acute and chronic conditions in which mitochondrial function or oxidative stress play a role. In addition, it is used as replacement therapy in patients with CoQ deficiency including inborn primary CoQ10 deficiency due to mutations in CoQ10-biosynthetic genes as well as secondary CoQ10 deficiency, which is frequently observed in patients with mitochondrial disease syndrome and in other conditions. However, despite many tests and some promising results, whether CoQ10 treatment is beneficial in any indication has remained inconclusive. Because CoQ10 is highly insoluble, it is only available in oral formulations, despite its very poor oral bioavailability. Using a novel model of CoQ-deficient cells, we screened a library of FDA-approved drugs for an activity that could increase the uptake of exogenous CoQ10 by the cell. We identified the fungicide caspofungin as capable of increasing the aqueous solubility of CoQ10 by several orders of magnitude. Caspofungin is a mild surfactant that solubilizes CoQ10 by forming nano-micelles with unique properties favoring stability and cellular uptake. Intravenous administration of the formulation in mice achieves unprecedented increases in CoQ10 plasma levels and in tissue uptake, with no observable toxicity. As it contains only two safe components (caspofungin and CoQ10), this injectable formulation presents a high potential for clinical safety and efficacy. Coenzyme Q10 (CoQ10) can be solubilized by the antifungal drug caspofungin (CF). CF is a mild surfactant and solubilizes CoQ10 in water by forming micellar structures with a high CoQ10 content. CF/CoQ10 micelles have unique properties favoring rapid and efficient uptake into cells and mitochondria. CF/CoQ10 micelles can be intravenously administrated without signs of toxicity. Intravenous administration of CF/CoQ10 in mice achieves unprecedented elevation of CoQ10 plasma levels and tissue uptake.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada.
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10
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Kramer-Drauberg M, Liu JL, Desjardins D, Wang Y, Branicky R, Hekimi S. ROS regulation of RAS and vulva development in Caenorhabditis elegans. PLoS Genet 2020; 16:e1008838. [PMID: 32544191 PMCID: PMC7319342 DOI: 10.1371/journal.pgen.1008838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 06/26/2020] [Accepted: 05/07/2020] [Indexed: 12/28/2022] Open
Abstract
Reactive oxygen species (ROS) are signalling molecules whose study in intact organisms has been hampered by their potential toxicity. This has prevented a full understanding of their role in organismal processes such as development, aging and disease. In Caenorhabditis elegans, the development of the vulva is regulated by a signalling cascade that includes LET-60ras (homologue of mammalian Ras), MPK-1 (ERK1/2) and LIN-1 (an ETS transcription factor). We show that both mitochondrial and cytoplasmic ROS act on a gain-of-function (gf) mutant of the LET-60ras protein through a redox-sensitive cysteine (C118) previously identified in mammals. We show that the prooxidant paraquat as well as isp-1, nuo-6 and sod-2 mutants, which increase mitochondrial ROS, inhibit the activity of LET-60rasgf on vulval development. In contrast, the antioxidant NAC and loss of sod-1, both of which decrease cytoplasmic H202, enhance the activity of LET-60rasgf. CRISPR replacement of C118 with a non-oxidizable serine (C118S) stimulates LET-60rasgf activity, whereas replacement of C118 with aspartate (C118D), which mimics a strongly oxidised cysteine, inhibits LET-60rasgf. These data strongly suggest that C118 is oxidized by cytoplasmic H202 generated from dismutation of mitochondrial and/or cytoplasmic superoxide, and that this oxidation inhibits LET-60ras. This contrasts with results in cultured mammalian cells where it is mostly nitric oxide, which is not found in worms, that oxidizes C118 and activates Ras. Interestingly, PQ, NAC and the C118S mutation do not act on the phosphorylation of MPK-1, suggesting that oxidation of LET-60ras acts on an as yet uncharacterized MPK-1-independent pathway. We also show that elevated cytoplasmic superoxide promotes vulva formation independently of C118 of LET-60ras and downstream of LIN-1. Finally, we uncover a role for the NADPH oxidases (BLI-3 and DUOX-2) and their redox-sensitive activator CED-10rac in stimulating vulva development. Thus, there are at least three genetically separable pathways by which ROS regulates vulval development.
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Affiliation(s)
| | - Ju-Ling Liu
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - David Desjardins
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Robyn Branicky
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
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11
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Krabbendam IE, Honrath B, Dilberger B, Iannetti EF, Branicky RS, Meyer T, Evers B, Dekker FJ, Koopman WJH, Beyrath J, Bano D, Schmidt M, Bakker BM, Hekimi S, Culmsee C, Eckert GP, Dolga AM. SK channel-mediated metabolic escape to glycolysis inhibits ferroptosis and supports stress resistance in C. elegans. Cell Death Dis 2020; 11:263. [PMID: 32327637 PMCID: PMC7181639 DOI: 10.1038/s41419-020-2458-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 04/01/2020] [Accepted: 04/01/2020] [Indexed: 12/25/2022]
Abstract
Metabolic flexibility is an essential characteristic of eukaryotic cells in order to adapt to physiological and environmental changes. Especially in mammalian cells, the metabolic switch from mitochondrial respiration to aerobic glycolysis provides flexibility to sustain cellular energy in pathophysiological conditions. For example, attenuation of mitochondrial respiration and/or metabolic shifts to glycolysis result in a metabolic rewiring that provide beneficial effects in neurodegenerative processes. Ferroptosis, a non-apoptotic form of cell death triggered by an impaired redox balance is gaining attention in the field of neurodegeneration. We showed recently that activation of small-conductance calcium-activated K+ (SK) channels modulated mitochondrial respiration and protected neuronal cells from oxidative death. Here, we investigated whether SK channel activation with CyPPA induces a glycolytic shift thereby increasing resilience of neuronal cells against ferroptosis, induced by erastin in vitro and in the nematode C. elegans exposed to mitochondrial poisons in vivo. High-resolution respirometry and extracellular flux analysis revealed that CyPPA, a positive modulator of SK channels, slightly reduced mitochondrial complex I activity, while increasing glycolysis and lactate production. Concomitantly, CyPPA rescued the neuronal cells from ferroptosis, while scavenging mitochondrial ROS and inhibiting glycolysis reduced its protection. Furthermore, SK channel activation increased survival of C. elegans challenged with mitochondrial toxins. Our findings shed light on metabolic mechanisms promoted through SK channel activation through mitohormesis, which enhances neuronal resilience against ferroptosis in vitro and promotes longevity in vivo.
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Affiliation(s)
- Inge E Krabbendam
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Birgit Honrath
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
- German Center for Neurodegenerative Diseases (DZNE) e.V., Sigmund-Freud-Straße 27, 53127, Bonn, Germany
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Philipps-Universität Marburg, Karl-von-Frisch-Straße 2, Marburg, 35032, Germany
| | - Benjamin Dilberger
- Faculty of Agricultural Sciences, Nutritional Sciences, and Environmental Management, Institute of Nutritional Sciences, Justus-Liebig-University of Giessen, 35392, Giessen, Germany
| | - Eligio F Iannetti
- Khondrion, Philips van Leydenlaan 15, 6525EX, Nijmegen, The Netherlands
| | - Robyn S Branicky
- Department of Biology, McGill University, 1205 Ave Docteur Penfield, Montreal, QC, H3A 1B1, Canada
| | - Tammo Meyer
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Bernard Evers
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Frank J Dekker
- Department of Chemical and Pharmaceutical Biology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, Groningen, The Netherlands
| | - Werner J H Koopman
- Radboud University Medical Center, Department of Biochemistry (286), Nijmegen, The Netherlands
| | - Julien Beyrath
- Khondrion, Philips van Leydenlaan 15, 6525EX, Nijmegen, The Netherlands
| | - Daniele Bano
- German Center for Neurodegenerative Diseases (DZNE) e.V., Sigmund-Freud-Straße 27, 53127, Bonn, Germany
| | - Martina Schmidt
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Barbara M Bakker
- Department of Pediatrics, Section Systems Medicine of Metabolism and Signalling, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
- Systems Biology Centre for Energy Metabolism and Ageing, University of Groningen, University Medical Center Groningen, A. Deusinglaan 1, 9713 AV, Groningen, The Netherlands
| | - Siegfried Hekimi
- Department of Biology, McGill University, 1205 Ave Docteur Penfield, Montreal, QC, H3A 1B1, Canada
| | - Carsten Culmsee
- Institut für Pharmakologie und Klinische Pharmazie, Biochemisch-Pharmakologisches Centrum Marburg, Philipps-Universität Marburg, Karl-von-Frisch-Straße 2, Marburg, 35032, Germany
- Center for Mind Brain and Behavior-CMBB, University of Marburg, Hans-Meerwein-Straße 6, 35032, Marburg, Germany
| | - Gunter P Eckert
- Faculty of Agricultural Sciences, Nutritional Sciences, and Environmental Management, Institute of Nutritional Sciences, Justus-Liebig-University of Giessen, 35392, Giessen, Germany
| | - Amalia M Dolga
- Faculty of Science and Engineering, Department of Molecular Pharmacology, Groningen Research Institute of Pharmacy (GRIP), University of Groningen, 9713 AV, Groningen, The Netherlands.
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12
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Abstract
Ubiquinone (UQ, coenzyme Q) is an essential electron transfer lipid in the mitochondrial respiratory chain. It is a main source of mitochondrial reactive oxygen species (ROS) but also has antioxidant properties. This mix of characteristics is why ubiquinone supplementation is considered a potential therapy for many diseases involving mitochondrial dysfunction. Mutations in the ubiquinone biosynthetic pathway are increasingly being identified in patients. Furthermore, secondary ubiquinone deficiency is a common finding associated with mitochondrial disorders and might exacerbate these conditions. Recent developments have suggested that ubiquinone biosynthesis occurs in discrete domains of the mitochondrial inner membrane close to ER-mitochondria contact sites. This spatial requirement for ubiquinone biosynthesis could be the link between secondary ubiquinone deficiency and mitochondrial dysfunction, which commonly results in loss of mitochondrial structural integrity.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Canada
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13
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Wang Y, Branicky R, Noë A, Hekimi S. Superoxide dismutases: Dual roles in controlling ROS damage and regulating ROS signaling. J Cell Biol 2018; 217:1915-1928. [PMID: 29669742 PMCID: PMC5987716 DOI: 10.1083/jcb.201708007] [Citation(s) in RCA: 879] [Impact Index Per Article: 146.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/13/2018] [Accepted: 04/04/2018] [Indexed: 02/07/2023] Open
Abstract
Wang et al. review the dual role of superoxide dismutases in controlling reactive oxygen species (ROS) damage and regulating ROS signaling across model systems as well as their involvement in human diseases. Superoxide dismutases (SODs) are universal enzymes of organisms that live in the presence of oxygen. They catalyze the conversion of superoxide into oxygen and hydrogen peroxide. Superoxide anions are the intended product of dedicated signaling enzymes as well as the byproduct of several metabolic processes including mitochondrial respiration. Through their activity, SOD enzymes control the levels of a variety of reactive oxygen species (ROS) and reactive nitrogen species, thus both limiting the potential toxicity of these molecules and controlling broad aspects of cellular life that are regulated by their signaling functions. All aerobic organisms have multiple SOD proteins targeted to different cellular and subcellular locations, reflecting the slow diffusion and multiple sources of their substrate superoxide. This compartmentalization also points to the need for fine local control of ROS signaling and to the possibility for ROS to signal between compartments. In this review, we discuss studies in model organisms and humans, which reveal the dual roles of SOD enzymes in controlling damage and regulating signaling.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Canada
| | - Robyn Branicky
- Department of Biology, McGill University, Montreal, Canada
| | - Alycia Noë
- Department of Biology, McGill University, Montreal, Canada
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14
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Abstract
The conserved E3 ubiquitin ligase CHIP/CHN-1 contributes to proteostasis by ubiquitylating HSP70 and HSP90-interacting proteins. In a recent issue of Cell,Tawo et al. (2017) show that CHIP/CHN-1 also directly ubiquitylates the insulin receptor INSR/DAF-2 to regulate its turnover. These findings suggest an unexpected interpretation of the effects of altered proteostasis on survival.
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Affiliation(s)
- Robyn Branicky
- Department of Biology, McGill University, Montreal H3A 1B1, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal H3A 1B1, Canada.
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15
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Affiliation(s)
- Bryan G Hughes
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
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16
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Wang Y, Smith C, Parboosingh JS, Khan A, Innes M, Hekimi S. Pathogenicity of two COQ7 mutations and responses to 2,4-dihydroxybenzoate bypass treatment. J Cell Mol Med 2017; 21:2329-2343. [PMID: 28409910 PMCID: PMC5618687 DOI: 10.1111/jcmm.13154] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 02/10/2017] [Indexed: 01/22/2023] Open
Abstract
Primary ubiquinone (co‐enzyme Q) deficiency results in a wide range of clinical features due to mitochondrial dysfunction. Here, we analyse and characterize two mutations in the ubiquinone biosynthetic gene COQ7. One mutation from the only previously identified patient (V141E), and one (L111P) from a 6‐year‐old girl who presents with spasticity and bilateral sensorineural hearing loss. We used patient fibroblast cell lines and a heterologous expression system to show that both mutations lead to loss of protein stability and decreased levels of ubiquinone that correlate with the severity of mitochondrial dysfunction. The severity of L111P is enhanced by the particular COQ7 polymorphism (T103M) that the patient carries, but not by a mitochondrial DNA mutation (A1555G) that is also present in the patient and that has been linked to aminoglycoside‐dependent hearing loss. We analysed treatment with the unnatural biosynthesis precursor 2,4‐dihydroxybenzoate (DHB), which can restore ubiquinone synthesis in cells completely lacking the enzymatic activity of COQ7. We find that the treatment is not beneficial for every COQ7 mutation and its outcome depends on the extent of enzyme activity loss.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - Christopher Smith
- Department of Medical Genetics, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada
| | - Jillian S Parboosingh
- Department of Medical Genetics, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital, Research Institute for Child and Maternal Health, University of Calgary, Calgary, Alberta, Canada
| | - Aneal Khan
- Metabolic Diseases Clinic, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada
| | - Micheil Innes
- Department of Medical Genetics, Alberta Children's Hospital, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital, Research Institute for Child and Maternal Health, University of Calgary, Calgary, Alberta, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montréal, Quebec, Canada
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17
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Branicky R, Hekimi S. Making a splash with splicing. Cell Res 2017; 27:457-458. [PMID: 28233771 DOI: 10.1038/cr.2017.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In a recent Nature paper, Heintz et al. identify a splicing factor (SFA-1) that is crucial for the longevity conferred by dietary restriction and the TORC1 pathway modulation in C. elegans.
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Affiliation(s)
- Robyn Branicky
- Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada H3A 1B1
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18
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Desjardins D, Cacho-Valadez B, Liu JL, Wang Y, Yee C, Bernard K, Khaki A, Breton L, Hekimi S. Antioxidants reveal an inverted U-shaped dose-response relationship between reactive oxygen species levels and the rate of aging in Caenorhabditis elegans. Aging Cell 2017; 16:104-112. [PMID: 27683245 PMCID: PMC5242296 DOI: 10.1111/acel.12528] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/16/2016] [Indexed: 01/09/2023] Open
Abstract
Reactive oxygen species (ROS) are potentially toxic, but they are also signaling molecules that modulate aging. Recent observations that ROS can promote longevity have to be reconciled with the numerous claims about the benefits of antioxidants on lifespan. Here, three antioxidants [N-acetylcysteine (NAC), vitamin C, and resveratrol (RSV)] were tested on Caenorhabditis elegans mutants that alter drug uptake, mitochondrial function, and ROS metabolism. We observed that like pro-oxidants, antioxidants can both lengthen and shorten lifespan, dependent on concentration, genotypes, and conditions. The effects of antioxidants thus reveal an inverted U-shaped dose-response relationship between ROS levels and lifespan. In addition, we observed that RSV can act additively to both NAC and paraquat, to dramatically increase lifespan. This suggests that the effect of compounds that modulate ROS levels can be additive when their loci of action or mechanisms of action are sufficiently distinct.
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Affiliation(s)
- David Desjardins
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
| | | | - Ju-Ling Liu
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
| | - Ying Wang
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
| | - Callista Yee
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
| | - Kristine Bernard
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
| | - Arman Khaki
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
| | - Lionel Breton
- L'Oréal Research and Innovation; Aulnay sous bois 93600 France
| | - Siegfried Hekimi
- Department of Biology; McGill University; Montreal QC Canada H3A 1B1
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19
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Blanchette CR, Thackeray A, Perrat PN, Hekimi S, Bénard CY. Functional Requirements for Heparan Sulfate Biosynthesis in Morphogenesis and Nervous System Development in C. elegans. PLoS Genet 2017; 13:e1006525. [PMID: 28068429 PMCID: PMC5221758 DOI: 10.1371/journal.pgen.1006525] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 12/06/2016] [Indexed: 12/28/2022] Open
Abstract
The regulation of cell migration is essential to animal development and physiology. Heparan sulfate proteoglycans shape the interactions of morphogens and guidance cues with their respective receptors to elicit appropriate cellular responses. Heparan sulfate proteoglycans consist of a protein core with attached heparan sulfate glycosaminoglycan chains, which are synthesized by glycosyltransferases of the exostosin (EXT) family. Abnormal HS chain synthesis results in pleiotropic consequences, including abnormal development and tumor formation. In humans, mutations in either of the exostosin genes EXT1 and EXT2 lead to osteosarcomas or multiple exostoses. Complete loss of any of the exostosin glycosyltransferases in mouse, fish, flies and worms leads to drastic morphogenetic defects and embryonic lethality. Here we identify and study previously unavailable viable hypomorphic mutations in the two C. elegans exostosin glycosyltransferases genes, rib-1 and rib-2. These partial loss-of-function mutations lead to a severe reduction of HS levels and result in profound but specific developmental defects, including abnormal cell and axonal migrations. We find that the expression pattern of the HS copolymerase is dynamic during embryonic and larval morphogenesis, and is sustained throughout life in specific cell types, consistent with HSPGs playing both developmental and post-developmental roles. Cell-type specific expression of the HS copolymerase shows that HS elongation is required in both the migrating neuron and neighboring cells to coordinate migration guidance. Our findings provide insights into general principles underlying HSPG function in development. During animal development, cells and neurons navigate long distances to reach their final target destinations. Migrating cells are guided by extracellular molecular cues, and cellular responses to these cues are regulated by heparan sulfate proteoglycans. Heparan sulfate proteoglycans are proteins with long heparan sulfate polysaccharide chains attached. Here we identify and study previously unavailable viable mutants that disrupt the elongation of the heparan sulfate chains in the nematode C. elegans. Our analysis shows that these HS-chain-elongation mutations affect the development of the nervous system as they result in misguided migrations of neurons and axons. Furthermore, we find that heparan sulfate chain elongation occurs in numerous cell types during development and that the coordinated production of heparan sulfate proteoglycans, in both the migrating cell and neighboring tissues, ensures proper migration. Our findings highlight the critical roles of heparan sulfate proteoglycans in nervous system development and the evolutionary conservation of the molecular mechanisms driving guided migrations.
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Affiliation(s)
- Cassandra R. Blanchette
- Department of Neurobiology, UMass Medical School, Worcester, Massachusetts, United States of America
| | - Andrea Thackeray
- Department of Neurobiology, UMass Medical School, Worcester, Massachusetts, United States of America
| | - Paola N. Perrat
- Department of Neurobiology, UMass Medical School, Worcester, Massachusetts, United States of America
| | | | - Claire Y. Bénard
- Department of Neurobiology, UMass Medical School, Worcester, Massachusetts, United States of America
- Department of Biological Sciences, University of Quebec at Montreal, Montreal, Canada
- * E-mail: ,
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20
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Hekimi S, Wang Y, Noë A. Mitochondrial ROS and the Effectors of the Intrinsic Apoptotic Pathway in Aging Cells: The Discerning Killers! Front Genet 2016; 7:161. [PMID: 27683586 PMCID: PMC5021979 DOI: 10.3389/fgene.2016.00161] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 08/30/2016] [Indexed: 01/06/2023] Open
Abstract
It has become clear that mitochondrial reactive oxygen species (mtROS) are not simply villains and mitochondria the hapless targets of their attacks. Rather, it appears that mitochondrial dysfunction itself and the signaling function of mtROS can have positive effects on lifespan, helping to extend longevity. If events in the mitochondria can lead to better cellular homeostasis and better survival of the organism in ways beyond providing ATP and biosynthetic products, we can conjecture that they act on other cellular components through appropriate signaling pathways. We describe recent advances in a variety of species which promoted our understanding of how changes of mtROS generation are part of a system of signaling pathways that emanate from the mitochondria to impact organism lifespan through global changes, including in transcriptional patterns. In unraveling this, many old players in cellular homeostasis were encountered. Among these, maybe most strikingly, is the intrinsic apoptotic signaling pathway, which is the conduit by which at least one class of mtROS exercise their actions in the nematode Caenorhabditis elegans. This is a pathway that normally contributes to organismal homeostasis by killing defective or otherwise unwanted cells, and whose various compounds have also been implicated in other cellular processes. However, it was a surprise that that appropriate activation of a cell killing pathway can in fact prolong the lifespan of the organism. In the soma of adult C. elegans, all cells are post-mitotic, like many of our neurons and possibly some of our immune cells. These cells cannot simply be killed and replaced when showing signs of dysfunction. Thus, we speculate that it is the ability of the apoptotic pathway to pull together information about the functional and structural integrity of different cellular compartments that is the key property for why this pathway is used to decide when to boost defensive and repair processes in irreplaceable cells. When this process is artificially stimulated in mutants with elevated mtROS generation or with drug treatments it leads to lifespan prolongations beyond the normal lifespan of the organism.
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Affiliation(s)
| | - Ying Wang
- Department of Biology, McGill University Montreal, QC, Canada
| | - Alycia Noë
- Department of Biology, McGill University Montreal, QC, Canada
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21
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Abstract
Mitochondria generate adenosine 5'-triphosphate (ATP) and are a source of potentially toxic reactive oxygen species (ROS). It has been suggested that the gradual mitochondrial dysfunction that is observed to accompany aging could in fact be causal to the aging process. Here we review findings that suggest that age-dependent mitochondrial dysfunction is not sufficient to limit life span. Furthermore, mitochondrial ROS are not always deleterious and can even stimulate pro-longevity pathways. Thus, mitochondrial dysfunction plays a complex role in regulating longevity.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada.
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22
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Ben‐Meir A, Burstein E, Borrego‐Alvarez A, Chong J, Wong E, Yavorska T, Naranian T, Chi M, Wang Y, Bentov Y, Alexis J, Meriano J, Sung H, Gasser DL, Moley KH, Hekimi S, Casper RF, Jurisicova A. Coenzyme Q10 restores oocyte mitochondrial function and fertility during reproductive aging. Aging Cell 2015; 14:887-95. [PMID: 26111777 PMCID: PMC4568976 DOI: 10.1111/acel.12368] [Citation(s) in RCA: 261] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2015] [Indexed: 12/21/2022] Open
Abstract
Female reproductive capacity declines dramatically in the fourth decade of life as a result of an age-related decrease in oocyte quality and quantity. The primary causes of reproductive aging and the molecular factors responsible for decreased oocyte quality remain elusive. Here, we show that aging of the female germ line is accompanied by mitochondrial dysfunction associated with decreased oxidative phosphorylation and reduced Adenosine tri-phosphate (ATP) level. Diminished expression of the enzymes responsible for CoQ production, Pdss2 and Coq6, was observed in oocytes of older females in both mouse and human. The age-related decline in oocyte quality and quantity could be reversed by the administration of CoQ10. Oocyte-specific disruption of Pdss2 recapitulated many of the mitochondrial and reproductive phenotypes observed in the old females including reduced ATP production and increased meiotic spindle abnormalities, resulting in infertility. Ovarian reserve in the oocyte-specific Pdss2-deficient animals was diminished, leading to premature ovarian failure which could be prevented by maternal dietary administration of CoQ10. We conclude that impaired mitochondrial performance created by suboptimal CoQ10 availability can drive age-associated oocyte deficits causing infertility.
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Affiliation(s)
- Assaf Ben‐Meir
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- TCART Fertility Partners 150 Bloor W Toronto ON M5S 2X9Canada
| | - Eliezer Burstein
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- TCART Fertility Partners 150 Bloor W Toronto ON M5S 2X9Canada
| | - Aluet Borrego‐Alvarez
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
| | - Jasmine Chong
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
| | - Ellen Wong
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- Department of Physiology University of Toronto 1 King's College Circle Toronto ON M5S 1A8Canada
| | - Tetyana Yavorska
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- Department of Physiology University of Toronto 1 King's College Circle Toronto ON M5S 1A8Canada
| | - Taline Naranian
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- Department of Physiology University of Toronto 1 King's College Circle Toronto ON M5S 1A8Canada
| | - Maggie Chi
- Department of Obstetrics and Gynecology Washington University in St. Louis 660 S. Euclid Avenue St. Louis MO 63110USA
| | - Ying Wang
- Department of Biology McGill University 3649 Promenade Sir William Osler Montreal QC H3G 0B1Canada
| | - Yaakov Bentov
- TCART Fertility Partners 150 Bloor W Toronto ON M5S 2X9Canada
- Department of Obstetrics and Gynecology University of Toronto 92 College Street Toronto ON M5G 1L4Canada
| | - Jennifer Alexis
- LifeQuest Centre for Reproductive Medicine 655 Bay St Toronto ON M5G 2K4Canada
| | - James Meriano
- LifeQuest Centre for Reproductive Medicine 655 Bay St Toronto ON M5G 2K4Canada
| | - Hoon‐Ki Sung
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
| | - David L. Gasser
- Department of Genetics University of Pennsylvania 575 Clinical Research Building 415 Curie Boulevard Philadelphia PA 19104‐6145 USA
| | - Kelle H. Moley
- Department of Obstetrics and Gynecology Washington University in St. Louis 660 S. Euclid Avenue St. Louis MO 63110USA
| | - Siegfried Hekimi
- Department of Biology McGill University 3649 Promenade Sir William Osler Montreal QC H3G 0B1Canada
| | - Robert F. Casper
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- TCART Fertility Partners 150 Bloor W Toronto ON M5S 2X9Canada
- Department of Physiology University of Toronto 1 King's College Circle Toronto ON M5S 1A8Canada
- Department of Obstetrics and Gynecology University of Toronto 92 College Street Toronto ON M5G 1L4Canada
| | - Andrea Jurisicova
- Lunenfeld‐Tanenbaum Research Institute Mount Sinai Hospital 25 Orde Street Toronto ON M5T 3H7Canada
- Department of Physiology University of Toronto 1 King's College Circle Toronto ON M5S 1A8Canada
- Department of Obstetrics and Gynecology University of Toronto 92 College Street Toronto ON M5G 1L4Canada
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Lapointe J, Hughes B, Bigras E, Hekimi S. Compensatory elevation of voluntary activity in mouse mutants with impaired mitochondrial energy metabolism. Physiol Rep 2014; 2:2/11/e12214. [PMID: 25413331 PMCID: PMC4255820 DOI: 10.14814/phy2.12214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mitochondria play a crucial role in determining whole‐body metabolism and exercise
capacity. Genetic mouse models of mild mitochondrial dysfunction provide an opportunity to
understand how mitochondrial function affects these parameters. MCLK1 (a.k.a. Coq7) is an enzyme
implicated in the biosynthesis of ubiquinone (UQ; Coenzyme Q). Low levels of MCLK1 in
Mclk1+/− heterozygous mutants lead to abnormal
sub‐mitochondrial distribution of UQ, impaired mitochondrial function, elevated mitochondrial
oxidative stress, and increased lifespan. Here, we report that young
Mclk1+/− males, but not females, show a significant
decrease in whole‐body metabolic rate as measured by indirect calorimetry. Such a
sex‐specific effect of mitochondrial dysfunction on energy metabolism has also been reported
for heterozygous mice carrying a mutation for the gene encoding the “Rieske” protein
of mitochondrial complex III
(RISP+/P224S). We find that both
Mclk1+/− and
RISP+/P224S males are capable of
restoring their defective metabolic rates by making significantly more voluntary use of a running
wheel compared to wild type. However, this increase in voluntary activity does not reflect their
exercise capacity, which we found to be impaired as revealed by a shorter treadmill distance run
before exhaustion. In contrast to what is observed in
Mclk1+/− and
RISP+/P224S mutants,
Sod2+/− mice with elevated oxidative stress and
major mitochondrial dysfunction did not increase voluntary activity. Our study reveals a
sex‐specific effect on how impaired mitochondrial function impacts whole‐body energy
metabolism and locomotory behavior, and contributes to the understanding of the metabolic and
behavioral consequences of mitochondrial disorders. Mitochondria play a crucial role in determining whole‐body metabolism, lifespan and
exercise capacity. This study reports sex‐specific effects of mitochondrial dysfunction,
resulting in increased spontaneous activity in response to impaired metabolic rates. These findings
contribute to the understanding of the metabolic and behavioral consequences of mitochondrial
disorders.
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Affiliation(s)
- Jérôme Lapointe
- Department of Biology, McGill University, Montréal, Quebec, Canada Agriculture and Agri-Food Canada, 2000 College St., Sherbrooke, J1M 0C8, Quebec, Canada
| | - Bryan Hughes
- Department of Biology, McGill University, Montréal, Quebec, Canada Department of Pharmacology, University of Alberta, Edmonton, T6G 2S2, Alberta, Canada
| | - Eve Bigras
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montréal, Quebec, Canada
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24
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Abstract
The mitochondria of slowly aging Mclk1+/− mutant mice produce high levels of reactive oxygen species (ROS). These animals display enhanced immune reactivity in response to lipopolysaccharide, Salmonella, and tumor-cell grafts, experience limited damage from these treatments and are partially protected from infection and tumorigenesis. We propose that the activation of the immune system by mitochondrial ROS reduces the rate of aging.
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25
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Yee C, Yang W, Hekimi S. The intrinsic apoptosis pathway mediates the pro-longevity response to mitochondrial ROS in C. elegans. Cell 2014; 157:897-909. [PMID: 24813612 DOI: 10.1016/j.cell.2014.02.055] [Citation(s) in RCA: 230] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 01/14/2014] [Accepted: 02/19/2014] [Indexed: 12/21/2022]
Abstract
The increased longevity of the C. elegans electron transport chain mutants isp-1 and nuo-6 is mediated by mitochondrial ROS (mtROS) signaling. Here we show that the mtROS signal is relayed by the conserved, mitochondria-associated, intrinsic apoptosis signaling pathway (CED-9/Bcl2, CED-4/Apaf1, and CED-3/Casp9) triggered by CED-13, an alternative BH3-only protein. Activation of the pathway by an elevation of mtROS does not affect apoptosis but protects from the consequences of mitochondrial dysfunction by triggering a unique pattern of gene expression that modulates stress sensitivity and promotes survival. In vertebrates, mtROS induce apoptosis through the intrinsic pathway to protect from severely damaged cells. Our observations in nematodes demonstrate that sensing of mtROS by the apoptotic pathway can, independently of apoptosis, elicit protective mechanisms that keep the organism alive under stressful conditions. This results in extended longevity when mtROS generation is inappropriately elevated. These findings clarify the relationships between mitochondria, ROS, apoptosis, and aging.
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Affiliation(s)
- Callista Yee
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Wen Yang
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada.
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26
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Baruah A, Chang H, Hall M, Yuan J, Gordon S, Johnson E, Shtessel LL, Yee C, Hekimi S, Derry WB, Lee SS. CEP-1, the Caenorhabditis elegans p53 homolog, mediates opposing longevity outcomes in mitochondrial electron transport chain mutants. PLoS Genet 2014; 10:e1004097. [PMID: 24586177 PMCID: PMC3937132 DOI: 10.1371/journal.pgen.1004097] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 11/24/2013] [Indexed: 12/22/2022] Open
Abstract
Caenorhabditis elegans CEP-1 and its mammalian homolog p53 are critical for responding to diverse stress signals. In this study, we found that cep-1 inactivation suppressed the prolonged lifespan of electron transport chain (ETC) mutants, such as isp-1 and nuo-6, but rescued the shortened lifespan of other ETC mutants, such as mev-1 and gas-1. We compared the CEP-1-regulated transcriptional profiles of the long-lived isp-1 and the short-lived mev-1 mutants and, to our surprise, found that CEP-1 regulated largely similar sets of target genes in the two mutants despite exerting opposing effects on their longevity. Further analyses identified a small subset of CEP-1-regulated genes that displayed distinct expression changes between the isp-1 and mev-1 mutants. Interestingly, this small group of differentially regulated genes are enriched for the "aging" Gene Ontology term, consistent with the hypothesis that they might be particularly important for mediating the distinct longevity effects of CEP-1 in isp-1 and mev-1 mutants. We further focused on one of these differentially regulated genes, ftn-1, which encodes ferritin in C. elegans, and demonstrated that it specifically contributed to the extended lifespan of isp-1 mutant worms but did not affect the mev-1 mutant lifespan. We propose that CEP-1 responds to different mitochondrial ETC stress by mounting distinct compensatory responses accordingly to modulate animal physiology and longevity. Our findings provide insights into how mammalian p53 might respond to distinct mitochondrial stressors to influence cellular and organismal responses.
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Affiliation(s)
- Aiswarya Baruah
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Hsinwen Chang
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Mathew Hall
- Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jie Yuan
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Sarah Gordon
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Erik Johnson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Ludmila L. Shtessel
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
| | - Callista Yee
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - W. Brent Derry
- Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Siu Sylvia Lee
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Liu JL, Hekimi S. The impact of mitochondrial oxidative stress on bile acid-like molecules in C. elegans provides a new perspective on human metabolic diseases. Worm 2013; 2:e21457. [PMID: 24058856 PMCID: PMC3670457 DOI: 10.4161/worm.21457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/11/2012] [Indexed: 12/19/2022]
Abstract
C. elegans is a model used to study cholesterol metabolism and the functions of its metabolites. Several studies have reported that, in worms, cholesterol is not a structural component of the membrane as it is in vertebrates. However, as in other animals, it is used for the synthesis of steroid hormones that regulate physiological processes such as dauer formation, molting and defecation. After cholesterol is taken up by the gut, mechanisms of transport of cholesterol between tissues in C. elegans involve lipoproteins, as in mammals. A recent study shows that both cholesterol uptake and lipoprotein metabolism in C. elegans are regulated by molecules whose activities, biosynthesis, and secretion strongly resemble those of mammalian bile acids, which are metabolites of cholesterol that act on metabolism in a variety of ways. Importantly, it was found that oxidative stress upsets the regulation of the synthesis of these molecules. Given the known function of mammalian bile acids as metabolic regulators of lipid and glucose homeostasis, future investigations of the biology of C. elegans bile acid-like molecules could provide information on the etiology of human metabolic disorders that are characterized by elevated oxidative stress.
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Affiliation(s)
- Ju-Ling Liu
- Department of Biology; McGill University; Montreal, Québec, Canada
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28
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Abstract
Ubiquinone (UQ), a.k.a. coenzyme Q, is a redox-active lipid that participates in several cellular processes, in particular mitochondrial electron transport. Primary UQ deficiency is a rare but severely debilitating condition. Mclk1 (a.k.a. Coq7) encodes a conserved mitochondrial enzyme that is necessary for UQ biosynthesis. We engineered conditional Mclk1 knockout models to study pathogenic effects of UQ deficiency and to assess potential therapeutic agents for the treatment of UQ deficiencies. We found that Mclk1 knockout cells are viable in the total absence of UQ. The UQ biosynthetic precursor DMQ9 accumulates in these cells and can sustain mitochondrial respiration, albeit inefficiently. We demonstrated that efficient rescue of the respiratory deficiency in UQ-deficient cells by UQ analogues is side chain length dependent, and that classical UQ analogues with alkyl side chains such as idebenone and decylUQ are inefficient in comparison with analogues with isoprenoid side chains. Furthermore, Vitamin K2, which has an isoprenoid side chain, and has been proposed to be a mitochondrial electron carrier, had no efficacy on UQ-deficient mouse cells. In our model with liver-specific loss of Mclk1, a large depletion of UQ in hepatocytes caused only a mild impairment of respiratory chain function and no gross abnormalities. In conjunction with previous findings, this surprisingly small effect of UQ depletion indicates a nonlinear dependence of mitochondrial respiratory capacity on UQ content. With this model, we also showed that diet-derived UQ10 is able to functionally rescue the electron transport deficit due to severe endogenous UQ deficiency in the liver, an organ capable of absorbing exogenous UQ.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montréal, Quebec, Canada H3A 1B1
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29
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Abstract
Ubiquinone (UQ), also known as coenzyme Q (CoQ), is a redox-active lipid present in all cellular membranes where it functions in a variety of cellular processes. The best known functions of UQ are to act as a mobile electron carrier in the mitochondrial respiratory chain and to serve as a lipid soluble antioxidant in cellular membranes. All eukaryotic cells synthesize their own UQ. Most of the current knowledge on the UQ biosynthetic pathway was obtained by studying Escherichia coli and Saccharomyces cerevisiae UQ-deficient mutants. The orthologues of all the genes known from yeast studies to be involved in UQ biosynthesis have subsequently been found in higher organisms. Animal mutants with different genetic defects in UQ biosynthesis display very different phenotypes, despite the fact that in all these mutants the same biosynthetic pathway is affected. This review summarizes the present knowledge of the eukaryotic biosynthesis of UQ, with focus on the biosynthetic genes identified in animals, including Caenorhabditis elegans, rodents, and humans. Moreover, we review the phenotypes of mutants in these genes and discuss the functional consequences of UQ deficiency in general.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montréal, Quebec, Canada
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30
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Wang D, Wang Y, Argyriou C, Carrière A, Malo D, Hekimi S. An enhanced immune response of Mclk1⁺/⁻ mutant mice is associated with partial protection from fibrosis, cancer and the development of biomarkers of aging. PLoS One 2012; 7:e49606. [PMID: 23166727 PMCID: PMC3498213 DOI: 10.1371/journal.pone.0049606] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/11/2012] [Indexed: 01/01/2023] Open
Abstract
The immune response is essential for survival by destroying microorganisms and pre-cancerous cells. However, inflammation, one aspect of this response, can result in short- and long-term deleterious side-effects. Mclk1+/− mutant mice can be long-lived despite displaying a hair-trigger inflammatory response and chronically activated macrophages as a result of high mitochondrial ROS generation. Here we ask whether this phenotype is beneficial or simply tolerated. We used models of infection by Salmonella serovars and found that Mclk1+/− mutants mount a stronger immune response, control bacterial proliferation better, and are resistant to cell and tissue damage resulting from the response, including fibrosis and types of oxidative damage that are considered to be biomarkers of aging. Moreover, these same types of tissue damage were found to be low in untreated 23 months-old mutants. We also examined the initiation of tumour growth after transplantation of mouse LLC1 carcinoma cells into Mclk1+/− mutants, as well as during spontaneous tumorigenesis in Mclk1+/−Trp53+/− double mutants. Tumour latency was increased by the Mclk1+/− genotype in both models. Furthermore, we used the transplantation model to show that splenic CD8+ T lymphocytes from Mclk1+/− graft recipients show enhanced cytotoxicity against LLC1 cells in vitro. Mclk1+/− mutants thus display an association of an enhanced immune response with partial protection from age-dependent processes and from pathologies similar to those that are found with increased frequency during the aging process. This suggests that the immune phenotype of these mutants might contribute to their longevity. We discuss how these findings suggest a broader view of how the immune response might impact the aging process.
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Affiliation(s)
- Dantong Wang
- Department of Biology, McGill University, Montreal, Canada
| | - Ying Wang
- Department of Biology, McGill University, Montreal, Canada
| | | | | | - Danielle Malo
- Department of Medicine and Human Genetics, McGill University, Montreal, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Canada
- * E-mail:
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31
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Lapointe J, Wang Y, Bigras E, Hekimi S. The submitochondrial distribution of ubiquinone affects respiration in long-lived Mclk1+/2mice. J Gen Physiol 2012. [DOI: 10.1085/jgp1405oia8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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32
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Abstract
MCLK1 and COQ3 are mitochondrial enzymes necessary for ubiquinone biosynthesis, but only MCLK1 also regulates the partitioning of ubiquinone between mitochondrial membranes and affects longevity in mice. Mclk1 (also known as Coq7) and Coq3 code for mitochondrial enzymes implicated in the biosynthetic pathway of ubiquinone (coenzyme Q or UQ). Mclk1+/− mice are long-lived but have dysfunctional mitochondria. This phenotype remains unexplained, as no changes in UQ content were observed in these mutants. By producing highly purified submitochondrial fractions, we report here that Mclk1+/− mice present a unique mitochondrial UQ profile that was characterized by decreased UQ levels in the inner membrane coupled with increased UQ in the outer membrane. Dietary-supplemented UQ10 was actively incorporated in both mitochondrial membranes, and this was sufficient to reverse mutant mitochondrial phenotypes. Further, although homozygous Coq3 mutants die as embryos like Mclk1 homozygous null mice, Coq3+/− mice had a normal lifespan and were free of detectable defects in mitochondrial function or ubiquinone distribution. These findings indicate that MCLK1 regulates both UQ synthesis and distribution within mitochondrial membranes.
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34
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35
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Liu JL, Desjardins D, Branicky R, Agellon LB, Hekimi S. Mitochondrial oxidative stress alters a pathway in Caenorhabditis elegans strongly resembling that of bile acid biosynthesis and secretion in vertebrates. PLoS Genet 2012; 8:e1002553. [PMID: 22438816 PMCID: PMC3305355 DOI: 10.1371/journal.pgen.1002553] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 01/09/2012] [Indexed: 11/22/2022] Open
Abstract
Mammalian bile acids (BAs) are oxidized metabolites of cholesterol whose amphiphilic properties serve in lipid and cholesterol uptake. BAs also act as hormone-like substances that regulate metabolism. The Caenorhabditis elegans clk-1 mutants sustain elevated mitochondrial oxidative stress and display a slow defecation phenotype that is sensitive to the level of dietary cholesterol. We found that: 1) The defecation phenotype of clk-1 mutants is suppressed by mutations in tat-2 identified in a previous unbiased screen for suppressors of clk-1. TAT-2 is homologous to ATP8B1, a flippase required for normal BA secretion in mammals. 2) The phenotype is suppressed by cholestyramine, a resin that binds BAs. 3) The phenotype is suppressed by the knock-down of C. elegans homologues of BA–biosynthetic enzymes. 4) The phenotype is enhanced by treatment with BAs. 5) Lipid extracts from C. elegans contain an activity that mimics the effect of BAs on clk-1, and the activity is more abundant in clk-1 extracts. 6) clk-1 and clk-1;tat-2 double mutants show altered cholesterol content. 7) The clk-1 phenotype is enhanced by high dietary cholesterol and this requires TAT-2. 8) Suppression of clk-1 by tat-2 is rescued by BAs, and this requires dietary cholesterol. 9) The clk-1 phenotype, including the level of activity in lipid extracts, is suppressed by antioxidants and enhanced by depletion of mitochondrial superoxide dismutases. These observations suggest that C. elegans synthesizes and secretes molecules with properties and functions resembling those of BAs. These molecules act in cholesterol uptake, and their level of synthesis is up-regulated by mitochondrial oxidative stress. Future investigations should reveal whether these molecules are in fact BAs, which would suggest the unexplored possibility that the elevated oxidative stress that characterizes the metabolic syndrome might participate in disease processes by affecting the regulation of metabolism by BAs. Cholesterol metabolism, in particular the transport of cholesterol in the blood by lipoproteins, is an important determinant of human cardiovascular health. Bile acids are breakdown products of cholesterol that have detergent properties and are secreted into the gut by the liver. Bile acids carry out three distinct roles in cholesterol metabolism: 1) Their synthesis from cholesterol participates in cholesterol elimination. 2) They act as detergents in the uptake of dietary cholesterol from the gut. 3) They regulate many aspects of metabolism, including cholesterol metabolism, by molecular mechanisms similar to that of steroid hormones. We have found that cholesterol uptake and lipoprotein metabolism in the nematode Caenorhabditis elegans are regulated by molecules whose activities, biosynthesis, and secretion strongly resemble that of bile acids and which might be bile acids. Most importantly we have found that oxidative stress upsets the regulation of the synthesis of these molecules. The metabolic syndrome is a set of cardiovascular risk factors that include obesity, high blood cholesterol, hypertension, and insulin resistance. Given the function of bile acids as metabolic regulators, our findings with C. elegans suggest the unexplored possibility that the elevated oxidative stress that characterizes the metabolic syndrome may participate in mammalian disease processes by affecting the regulation of bile acid synthesis.
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Affiliation(s)
- Ju-Ling Liu
- Department of Biology, McGill University, Montreal, Canada
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36
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Robert F, Mills JR, Agenor A, Wang D, DiMarco S, Cencic R, Tremblay ML, Gallouzi IE, Hekimi S, Wing SS, Pelletier J. Targeting protein synthesis in a Myc/mTOR-driven model of anorexia-cachexia syndrome delays its onset and prolongs survival. Cancer Res 2011; 72:747-56. [PMID: 22158946 DOI: 10.1158/0008-5472.can-11-2739] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Anorexia-cachexia syndrome (ACS) is a major determinant of cancer-related death that causes progressive body weight loss due to depletion of skeletal muscle mass and body fat. Here, we report the development of a novel preclinical murine model of ACS in which lymphomas harbor elevated Myc and activated mTOR signaling. The ACS phenotype in this model correlated with deregulated expression of a number of cytokines, including elevated levels of interleukin-10 which was under the direct translational control of mTOR. Notably, pharmacologic intervention to impair protein synthesis restored cytokine production to near-normal levels, delayed ACS progression, and extended host survival. Together, our findings suggest a new paradigm to treat ACS by strategies which target protein synthesis to block the production of procachexic factors.
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Affiliation(s)
- Francis Robert
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
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37
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Hughes BG, Hekimi S. A mild impairment of mitochondrial electron transport has sex-specific effects on lifespan and aging in mice. PLoS One 2011; 6:e26116. [PMID: 22028811 PMCID: PMC3189954 DOI: 10.1371/journal.pone.0026116] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 09/19/2011] [Indexed: 11/29/2022] Open
Abstract
Impairments of various aspects of mitochondrial function have been associated with increased lifespan in various model organisms ranging from Caenorhabditis elegans to mice. For example, disruption of the function of the 'Rieske' iron-sulfur protein (RISP) of complex III of the mitochondrial electron transport chain can result in increased lifespan in the nematode worm C. elegans. However, the mechanisms by which impaired mitochondrial function affects aging remain under investigation, including whether or not they require decreased electron transport. We have generated knock-in mice with a loss-of-function Risp mutation that is homozygous lethal. However, heterozygotes (Risp(+/P224S)) were viable and had decreased levels of RISP protein and complex III enzymatic activity. This decrease was sufficient to impair mitochondrial respiration and to decrease overall metabolic rate in males, but not females. These defects did not appear to exert an overtly deleterious effect on the health of the mutants, since young Risp(+/P224S) mice are outwardly normal, with unaffected performance and fertility. Furthermore, biomarkers of oxidative stress were unaffected in both young and aged animals. Despite this, the average lifespan of male Risp(+/P224S) mice was shortened and aged Risp(+/P224S) males showed signs of more rapidly deteriorating health. In spite of these differences, analysis of Gompertz mortality parameters showed that Risp heterozygosity decreased the rate of increase of mortality with age and increased the intrinsic vulnerability to death in both sexes. However, the intrinsic vulnerability was increased more dramatically in males, which resulted in their shortened lifespan. For females, the slower acceleration of age-dependent mortality results in significantly increased survival of Risp(+/P224S) mice in the second half of lifespan. These results demonstrate that even relatively small perturbations of the mitochondrial electron transport chain can have significant physiological effects in mammals, and that the severity of those effects can be sex-dependent.
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Van Raamsdonk JM, Hekimi S. FUdR causes a twofold increase in the lifespan of the mitochondrial mutant gas-1. Mech Ageing Dev 2011; 132:519-21. [PMID: 21893079 DOI: 10.1016/j.mad.2011.08.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/10/2011] [Accepted: 08/20/2011] [Indexed: 11/25/2022]
Abstract
The nematode worm Caenorhabditis elegans has been used to identify hundreds of genes that influence longevity and thereby demonstrate the strong influence of genetics on lifespan determination. In order to simplify lifespan studies in worms, many researchers have employed 5-fluoro-2'-deoxyuridine (FUdR) to inhibit the development of progeny. While FUdR has little impact on the lifespan of wild-type worms, we demonstrate that FUdR causes a dramatic, dose-dependent, twofold increase in the lifespan of the mitochondrial mutant gas-1. Thus, the concentration of FUdR employed in a lifespan study can determine whether a particular strain is long-lived or short-lived compared to wild-type.
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Hekimi S, Lapointe J, Wen Y. Taking a "good" look at free radicals in the aging process. Trends Cell Biol 2011; 21:569-76. [PMID: 21824781 DOI: 10.1016/j.tcb.2011.06.008] [Citation(s) in RCA: 388] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 05/30/2011] [Accepted: 06/24/2011] [Indexed: 12/12/2022]
Abstract
The mitochondrial free radical theory of aging (MFRTA) proposes that aging is caused by damage to macromolecules by mitochondrial reactive oxygen species (ROS). This is based on the observed association of the rate of aging and the aged phenotype with the generation of ROS and oxidative damage. However, recent findings, in particular in Caenorhabditis elegans but also in rodents, suggest that ROS generation is not the primary or initial cause of aging. Here, we propose that ROS are tightly associated with aging because they play a role in mediating a stress response to age-dependent damage. This could generate the observed correlation between aging and ROS without implying that ROS damage is the earliest trigger or main cause of aging.
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Affiliation(s)
- Siegfried Hekimi
- Department of Biology, McGill University, Montréal, Canada H3A 1B1.
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Budinger GRS, Mutlu GM, Urich D, Soberanes S, Buccellato LJ, Hawkins K, Chiarella SE, Radigan KA, Eisenbart J, Agrawal H, Berkelhamer S, Hekimi S, Zhang J, Perlman H, Schumacker PT, Jain M, Chandel NS. Epithelial cell death is an important contributor to oxidant-mediated acute lung injury. Am J Respir Crit Care Med 2011; 183:1043-54. [PMID: 20959557 PMCID: PMC3086743 DOI: 10.1164/rccm.201002-0181oc] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 10/15/2010] [Indexed: 01/11/2023] Open
Abstract
RATIONALE Acute lung injury and the acute respiratory distress syndrome are characterized by increased lung oxidant stress and apoptotic cell death. The contribution of epithelial cell apoptosis to the development of lung injury is unknown. OBJECTIVES To determine whether oxidant-mediated activation of the intrinsic or extrinsic apoptotic pathway contributes to the development of acute lung injury. METHODS Exposure of tissue-specific or global knockout mice or cells lacking critical components of the apoptotic pathway to hyperoxia, a well-established mouse model of oxidant-induced lung injury, for measurement of cell death, lung injury, and survival. MEASUREMENTS AND MAIN RESULTS We found that the overexpression of SOD2 prevents hyperoxia-induced BAX activation and cell death in primary alveolar epithelial cells and prolongs the survival of mice exposed to hyperoxia. The conditional loss of BAX and BAK in the lung epithelium prevented hyperoxia-induced cell death in alveolar epithelial cells, ameliorated hyperoxia-induced lung injury, and prolonged survival in mice. By contrast, Cyclophilin D-deficient mice were not protected from hyperoxia, indicating that opening of the mitochondrial permeability transition pore is dispensable for hyperoxia-induced lung injury. Mice globally deficient in the BH3-only proteins BIM, BID, PUMA, or NOXA, which are proximal upstream regulators of BAX and BAK, were not protected against hyperoxia-induced lung injury suggesting redundancy of these proteins in the activation of BAX or BAK. CONCLUSIONS Mitochondrial oxidant generation initiates BAX- or BAK-dependent alveolar epithelial cell death, which contributes to hyperoxia-induced lung injury.
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Affiliation(s)
- G. R. Scott Budinger
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Gökhan M. Mutlu
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Daniela Urich
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Saul Soberanes
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Leonard J. Buccellato
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Keenan Hawkins
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sergio E. Chiarella
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Kathryn A. Radigan
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - James Eisenbart
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Hemant Agrawal
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Sara Berkelhamer
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Siegfried Hekimi
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jianke Zhang
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Harris Perlman
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Paul T. Schumacker
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Manu Jain
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Navdeep S. Chandel
- Department of Medicine, Department of Cell and Molecular Biology, and Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Biology, McGill University, Montreal, Quebec, Canada; and Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
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Hekimi S, Hughes B. Phylogenetic ubiquity of the effects of altered ubiquinone biosynthesis on survival. Aging (Albany NY) 2011; 3:184-185. [PMID: 21422496 PMCID: PMC3091514 DOI: 10.18632/aging.100310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 03/16/2011] [Indexed: 05/30/2023]
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Abstract
The free radical theory of aging proposes a causal relationship between reactive oxygen species (ROS) and aging. While it is clear that oxidative damage increases with age, its role in the aging process is uncertain. Testing the free radical theory of aging requires experimentally manipulating ROS production or detoxification and examining the resulting effects on lifespan. In this review, we examine the relationship between ROS and aging in the genetic model organism Caenorhabditis elegans, summarizing experiments using long-lived mutants, mutants with altered mitochondrial function, mutants with decreased antioxidant defenses, worms treated with antioxidant compounds, and worms exposed to different environmental conditions. While there is frequently a negative correlation between oxidative damage and lifespan, there are many examples in which they are uncoupled. Neither is resistance to oxidative stress sufficient for a long life nor are all long-lived mutants more resistant to oxidative stress. Similarly, sensitivity to oxidative stress does not necessarily shorten lifespan and is in fact compatible with long life. Overall, the data in C. elegans indicate that oxidative damage can be dissociated from aging in experimental situations.
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Abstract
The study of long-lived C. elegans mutants suggests that mitochondrial oxidants can actually help reduce aging by acting as stress signals, rather than acting solely as toxic molecules. The nuo-6 and isp-1 genes of C. elegans encode, respectively, subunits of complex I and III of the mitochondrial respiratory chain. Partial loss-of-function mutations in these genes decrease electron transport and greatly increase the longevity of C. elegans by a mechanism that is distinct from that induced by reducing their level of expression by RNAi. Electron transport is a major source of the superoxide anion (O⋅–), which in turn generates several types of toxic reactive oxygen species (ROS), and aging is accompanied by increased oxidative stress, which is an imbalance between the generation and detoxification of ROS. These observations have suggested that the longevity of such mitochondrial mutants might result from a reduction in ROS generation, which would be consistent with the mitochondrial oxidative stress theory of aging. It is difficult to measure ROS directly in living animals, and this has held back progress in determining their function in aging. Here we have adapted a technique of flow cytometry to directly measure ROS levels in isolated mitochondria to show that the generation of superoxide is elevated in the nuo-6 and isp-1 mitochondrial mutants, although overall ROS levels are not, and oxidative stress is low. Furthermore, we show that this elevation is necessary and sufficient to increase longevity, as it is abolished by the antioxidants NAC and vitamin C, and phenocopied by mild treatment with the prooxidant paraquat. Furthermore, the absence of effect of NAC and the additivity of the effect of paraquat on a variety of long- and short-lived mutants suggest that the pathway triggered by mitochondrial superoxide is distinct from previously studied mechanisms, including insulin signaling, dietary restriction, ubiquinone deficiency, the hypoxic response, and hormesis. These findings are not consistent with the mitochondrial oxidative stress theory of aging. Instead they show that increased superoxide generation acts as a signal in young mutant animals to trigger changes of gene expression that prevent or attenuate the effects of subsequent aging. We propose that superoxide is generated as a protective signal in response to molecular damage sustained during wild-type aging as well. This model provides a new explanation for the well-documented correlation between ROS and the aged phenotype as a gradual increase of molecular damage during aging would trigger a gradually stronger ROS response. An unequivocal demonstration that mitochondria are important for lifespan comes from studies with the nematode Caenorhabditis elegans. Mutations in mitochondrial proteins such as ISP-1 and NUO-6, which function directly in mitochondrial electron transport, lead to a dramatic increase in the lifespan of this organism. One theory proposes that toxicity of mitochondrial reactive oxygen species (ROS) is the cause of aging and predicts that the generation of the ROS superoxide should be low in these mutants. Here we have measured superoxide generation in these mutants and found that it is in fact elevated, rather than reduced. Furthermore, we found that this elevation is necessary and sufficient for longevity, as it is abolished by antioxidants and induced by mild treatment with oxidants. This suggests that superoxide can act as a signal triggering cellular changes that attenuate the effects of aging. This idea suggests a new model for the well-documented correlation between ROS and the aged phenotype. We propose that a gradual increase of molecular damage during aging triggers a concurrent, gradually intensifying, protective superoxide response.
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Affiliation(s)
- Wen Yang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Abstract
The strengths of the Caenorhabditis elegans model have been recently applied to the study of the pathways of lipid storage, transport, and signaling. As the lipid storage field has recently been reviewed, in this minireview we (1) discuss some recent studies revealing important physiological roles for lipases in mobilizing lipid reserves, (2) describe various pathways of lipid transport, with a particular focus on the roles of lipoproteins, (3) debate the utility of using C. elegans as a model for human dyslipidemias that impinge on atherosclerosis, and (4) describe several systems where lipids affect signaling, highlighting the particular properties of lipids as information-carrying molecules. We conclude that the study of lipid biology in C. elegans exemplifies the advantages afforded by a whole-animal model system where interactions between tissues and organs, and functions such as nutrient absorption, distribution, and storage, as well as reproduction can all be studied simultaneously.
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Affiliation(s)
- Robyn Branicky
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Abstract
In Caenorhabditis elegans, longevity is increased by a partial loss-of-function mutation in the mitochondrial complex III subunit gene isp-1. Longevity is also increased by RNAi against the expression of a variety of mitochondrial respiratory chain genes, including isp-1, but it is unknown whether the isp-1(qm150) mutation and the RNAi treatments trigger the same underlying mechanisms of longevity. We have identified nuo-6(qm200), a mutation in a conserved subunit of mitochondrial complex I (NUDFB4). The mutation reduces the function of complex I and, like isp-1(qm150), results in low oxygen consumption, slow growth, slow behavior, and increased lifespan. We have compared the phenotypes of nuo-6(qm200) to those of nuo-6(RNAi) and found them to be distinct in crucial ways, including patterns of growth and fertility, behavioral rates, oxygen consumption, ATP levels, autophagy, and resistance to paraquat, as well as expression of superoxide dismutases, mitochondrial heat-shock proteins, and other gene expression markers. RNAi treatments appear to generate a stress and autophagy response, while the genomic mutation alters electron transport and reactive oxygen species metabolism. For many phenotypes, we also compared isp-1(qm150) to isp-1(RNAi) and found the same pattern of differences. Most importantly, we found that, while the lifespan of nuo-6, isp-1 double mutants is not greater than that of the single mutants, the lifespan increase induced by nuo-6(RNAi) is fully additive to that induced by isp-1(qm150), and the increase induced by isp-1(RNAi) is fully additive to that induced by nuo-6(qm200). Our results demonstrate that distinct and separable aspects of mitochondrial biology affect lifespan independently.
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Affiliation(s)
- Wen Yang
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Blagosklonny MV, Campisi J, Sinclair DA, Bartke A, Blasco MA, Bonner WM, Bohr VA, Brosh RM, Brunet A, Depinho RA, Donehower LA, Finch CE, Finkel T, Gorospe M, Gudkov AV, Hall MN, Hekimi S, Helfand SL, Karlseder J, Kenyon C, Kroemer G, Longo V, Nussenzweig A, Osiewacz HD, Peeper DS, Rando TA, Rudolph KL, Sassone-Corsi P, Serrano M, Sharpless NE, Skulachev VP, Tilly JL, Tower J, Verdin E, Vijg J. Impact papers on aging in 2009. Aging (Albany NY) 2010; 2:111-21. [PMID: 20351400 PMCID: PMC2871240 DOI: 10.18632/aging.100132] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 03/22/2010] [Indexed: 01/09/2023]
Abstract
The editorial board of Aging reviews research papers published in 2009, which they
believe have or will have a significant impact on aging research. Among many
others, the topics include genes that accelerate aging or in contrast promote
longevity in model organisms, DNA damage responses and telomeres, molecular
mechanisms of life span extension by calorie restriction and pharmacologic
interventions into aging. The emerging message in 2009 is that aging is not
random but determined by a genetically-regulated longevity network and can be
decelerated both genetically and pharmacologically.
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Zheng H, Lapointe J, Hekimi S. Lifelong protection from global cerebral ischemia and reperfusion in long-lived Mclk1(+/)(-) mutants. Exp Neurol 2010; 223:557-65. [PMID: 20170652 DOI: 10.1016/j.expneurol.2010.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/01/2010] [Accepted: 02/09/2010] [Indexed: 01/07/2023]
Abstract
To achieve a long life span, animals must be resistant to various injuries as well as avoid or delay lethality from age-dependent diseases. Reduced expression of the mitochondrial enzyme CLK-1/MCLK1 (a.k.a. Coq7), a mitochondrial hydroxylase that is necessary for the biosynthesis of ubiquinone (UQ), extends lifespan in Caenorhabditiselegans and in mice. Here, we show that long-lived Mclk1(+/)(-) mutants have enhanced resistance to neurological damage following global cerebral ischemia-reperfusion (I/R) injury induced by transient bilateral common carotid artery occlusion (BCCAO). Both young ( approximately 100days old) and relatively aged ( approximately 450days old) mutants display increased resistance as indicated by a significant decrease in the amount of degenerating cells observed in forebrain cortex and in hippocampal areas after ischemia and reperfusion. Furthermore, less oxidative damage resulting from the procedure was measured in the brain of young Mclk1(+/)(-) animals. The finding that both young and old mutants are protected indicates that this is a basic phenotype of these mutants and not a secondary consequence of their slow rate of aging. Thus, the partial resistance to I/R injury suggests that Mclk1(+/)(-) mutants have an enhanced recovery potential following age-dependant vascular accidents, which correlates well with their longer survival. By relating this neuroprotective effect to previously reported characteristics of the Mclk1(+/)(-) phenotype, including altered mitochondrial metabolism and increased HIF-1alpha expression, this study establishes these mutants as useful models to analyze the mechanisms underlying tolerance to ischemia, particularly those associated with ischemic preconditioning, as well as to clarify the relation between aging and age-dependent diseases.
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Affiliation(s)
- Huaien Zheng
- Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, Canada H3A 1B1
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Abstract
According to the widely acknowledged mitochondrial free radical theory of aging (MFRTA), the macromolecular damage that results from the production of toxic reactive oxygen species (ROS) during cellular respiration is the cause of aging. However, although it is clear that oxidative damage increases during aging, the fundamental question regarding whether mitochondrial oxidative stress is in any way causal to the aging process remains unresolved. An increasing number of studies on long-lived vertebrate species, mutants and transgenic animals have seriously challenged the pervasive MFRTA. Here, we describe some of these new results, including those pertaining to the phenotype of the long-lived Mclk1(-/-) mice, which appear irreconcilable with the MFRTA. Thus, we believe that it is reasonable to now consider the MFRTA as refuted and that it is time to use the insight gained by many years of testing this theory to develop new views as to the physiological causes of aging.
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Affiliation(s)
- Jérôme Lapointe
- Department of Biology, McGill University, Montréal, H3A 1B1, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montréal, H3A 1B1, Canada
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Wang D, Malo D, Hekimi S. Elevated mitochondrial reactive oxygen species generation affects the immune response via hypoxia-inducible factor-1alpha in long-lived Mclk1+/- mouse mutants. J Immunol 2009; 184:582-90. [PMID: 20007531 DOI: 10.4049/jimmunol.0902352] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mitochondrial reactive oxygen species (ROS) are believed to stabilize hypoxia-inducible factor (HIF)-1alpha, a transcriptional regulator of the immune response. Mclk1 encodes a mitochondrial protein that is necessary for ubiquinone biosynthesis. Heterozygote Mclk1(+/-) mutant mice are long-lived despite increased mitochondrial ROS and decreased energy metabolism. In this study, Mclk1(+/-) mutant mice in the C57BL/6J background displayed increased basal and induced expression of HIF-1alpha in liver and macrophages in association with elevated expression of inflammatory cytokines, in particular TNF-alpha. Mutant macrophages showed increased classical and decreased alternative activation, and mutant mice were hypersensitive to LPS. Consistent with these observations in vivo, knock-down of Mclk1 in murine RAW264.7 macrophage-like cells induced increased mitochondrial ROS as well as elevated expression of HIF-1alpha and secretion of TNF-alpha. We used an antioxidant peptide targeted to mitochondria to show that altered ROS metabolism is necessary for the enhanced expression of HIF-1alpha, which, in turn, is necessary for increased TNF-alpha secretion. These findings provide in vivo evidence for the action of mitochondrial ROS on HIF-1alpha activity and demonstrate that changes in mitochondrial function within physiologically tolerable limits modulate the immune response. Our results further suggest that altered immune function through a limited increase in HIF-1alpha expression can positively impact animal longevity.
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Affiliation(s)
- Dantong Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Lapointe J, Stepanyan Z, Bigras E, Hekimi S. Reversal of the mitochondrial phenotype and slow development of oxidative biomarkers of aging in long-lived Mclk1+/- mice. J Biol Chem 2009; 284:20364-74. [PMID: 19478076 DOI: 10.1074/jbc.m109.006569] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although there is a consensus that mitochondrial function is somehow linked to the aging process, the exact role played by mitochondria in this process remains unresolved. The discovery that reduced activity of the mitochondrial enzyme CLK-1/MCLK1 (also known as COQ7) extends lifespan in both Caenorhabditis elegans and mice has provided a genetic model to test mitochondrial theories of aging. We have recently shown that the mitochondria of young, long-lived, Mclk1(+/-) mice are dysfunctional, exhibiting reduced energy metabolism and a substantial increase in oxidative stress. Here we demonstrate that this altered mitochondrial condition in young animals paradoxically results in an almost complete protection from the age-dependent loss of mitochondrial function as well as in a significant attenuation of the rate of development of oxidative biomarkers of aging. Moreover, we show that reduction in MCLK1 levels can also gradually prevent the deterioration of mitochondrial function and associated increase of global oxidative stress that is normally observed in Sod2(+/-) mutants. We hypothesize that the mitochondrial dysfunction observed in young Mclk1(+/-) mutants induces a physiological state that ultimately allows for their slow rate of aging. Thus, our study provides for a unique vertebrate model in which an initial alteration in a specific mitochondrial function is linked to long term beneficial effects on biomarkers of aging and, furthermore, provides for new evidence which indicates that mitochondrial oxidative stress is not causal to aging.
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Affiliation(s)
- Jérôme Lapointe
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
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