1
|
Yang NV, Rogers S, Guerra R, Pagliarini DJ, Theusch E, Krauss RM. TOMM40 and TOMM22 of the Translocase Outer Mitochondrial Membrane Complex rescue statin-impaired mitochondrial dynamics, morphology, and mitophagy in skeletal myotubes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.24.546411. [PMID: 37425714 PMCID: PMC10327005 DOI: 10.1101/2023.06.24.546411] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Background Statins are the drugs most commonly used for lowering plasma low-density lipoprotein (LDL) cholesterol levels and reducing cardiovascular disease risk. Although generally well tolerated, statins can induce myopathy, a major cause of non-adherence to treatment. Impaired mitochondrial function has been implicated as a cause of statin-induced myopathy, but the underlying mechanism remains unclear. We have shown that simvastatin downregulates transcription of TOMM40 and TOMM22 , genes that encode major subunits of the translocase of outer mitochondrial membrane (TOM) complex which is responsible for importing nuclear-encoded proteins and maintaining mitochondrial function. We therefore investigated the role of TOMM40 and TOMM22 in mediating statin effects on mitochondrial function, dynamics, and mitophagy. Methods Cellular and biochemical assays and transmission electron microscopy were used to investigate effects of simvastatin and TOMM40 and TOMM22 expression on measures of mitochondrial function and dynamics in C2C12 and primary human skeletal cell myotubes. Results Knockdown of TOMM40 and TOMM22 in skeletal cell myotubes impaired mitochondrial oxidative function, increased production of mitochondrial superoxide, reduced mitochondrial cholesterol and CoQ levels, disrupted mitochondrial dynamics and morphology, and increased mitophagy, with similar effects resulting from simvastatin treatment. Overexpression of TOMM40 and TOMM22 in simvastatin-treated muscle cells rescued statin effects on mitochondrial dynamics, but not on mitochondrial function or cholesterol and CoQ levels. Moreover, overexpression of these genes resulted in an increase in number and density of cellular mitochondria. Conclusion These results confirm that TOMM40 and TOMM22 are central in regulating mitochondrial homeostasis and demonstrate that downregulation of these genes by statin treatment mediates disruption of mitochondrial dynamics, morphology, and mitophagy, effects that may contribute to statin-induced myopathy. GRAPHICAL ABSTRACT
Collapse
|
2
|
Exosome mediated Tom40 delivery protects against hydrogen peroxide-induced oxidative stress by regulating mitochondrial function. PLoS One 2022; 17:e0272511. [PMID: 35951602 PMCID: PMC9371349 DOI: 10.1371/journal.pone.0272511] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 07/20/2022] [Indexed: 11/20/2022] Open
Abstract
Mitochondrial dysfunction is a hallmark of neurodegeneration. The expression level of Tom40, a crucial mitochondrial membrane protein, is significantly reduced in neurodegenerative disease subjects. Tom40 overexpression studies have shown to protect the neurons against oxidative stress by improving mitochondrial function. Thus, successful delivery of Tom40 protein to the brain could lead to a novel therapy for neurodegenerative diseases. However, delivering protein to the cell may be difficult. Especially the blood-brain barrier (BBB) is a big hurdle to clear in order to deliver the protein to the brain. In the current study, we engineered exosomes, which are the extracellular vesicles of endosomal origin, and able to cross BBB as delivery vehicles packing human Tom40. We found Tom40 protein delivery by the exosome successfully protected the cells against hydrogen peroxide-induced oxidative stress. This result suggests that exosome-mediated delivery of Tom40 may potentially be useful in restoring mitochondrial functions and alleviating oxidative stress in neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases.
Collapse
|
3
|
Jungtrakoon Thamtarana P, Marucci A, Pannone L, Bonnefond A, Pezzilli S, Biagini T, Buranasupkajorn P, Hastings T, Mendonca C, Marselli L, Di Paola R, Abubakar Z, Mercuri L, Alberico F, Flex E, Ceròn J, Porta-de-la-Riva M, Ludovico O, Carella M, Martinelli S, Marchetti P, Mazza T, Froguel P, Trischitta V, Doria A, Prudente S. Gain of Function of Malate Dehydrogenase 2 and Familial Hyperglycemia. J Clin Endocrinol Metab 2022; 107:668-684. [PMID: 34718610 PMCID: PMC8852227 DOI: 10.1210/clinem/dgab790] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Genes causing familial forms of diabetes mellitus are only partially known. OBJECTIVE We set out to identify the genetic cause of hyperglycemia in multigenerational families with an apparent autosomal dominant form of adult-onset diabetes not due to mutations in known monogenic diabetes genes. METHODS Existing whole-exome sequencing (WES) data were used to identify exonic variants segregating with diabetes in 60 families from the United States and Italy. Functional studies were carried out in vitro (transduced MIN6-K8 cells) and in vivo (Caenorhabditis elegans) to assess the diabetogenic potential of 2 variants in the malate dehydrogenase 2 (MDH2) gene linked with hyperglycemia in 2 of the families. RESULTS A very rare mutation (p.Arg52Cys) in MDH2 strongly segregated with hyperglycemia in 1 family from the United States. An infrequent MDH2 missense variant (p.Val160Met) also showed disease cosegregation in a family from Italy, although with reduced penetrance. In silico, both Arg52Cys and Val160Met were shown to affect MDH2 protein structure and function. In transfected HepG2 cells, both variants significantly increased MDH2 enzymatic activity, thereby decreasing the NAD+/NADH ratio-a change known to affect insulin signaling and secretion. Stable expression of human wild-type MDH2 in MIN6-K8 cell lines enhanced glucose- and GLP-1-stimulated insulin secretion. This effect was blunted by the Cys52 or Met160 substitutions. Nematodes carrying equivalent changes at the orthologous positions of the mdh-2 gene showed impaired glucose-stimulated insulin secretion. CONCLUSION Our findings suggest a central role of MDH2 in human glucose homeostasis and indicate that gain of function variants in this gene may be involved in the etiology of familial forms of diabetes.
Collapse
Affiliation(s)
- Prapaporn Jungtrakoon Thamtarana
- Research Division, Joslin Diabetes Center, and Harvard Medical School, Boston, MA, USA
- Cellular and Molecular Biology of Diabetes Research Group, Siriraj Center of Research Excellence for Diabetes and Obesity, Division of Molecular Medicine, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Antonella Marucci
- Research Unit of Diabetes and Endocrine Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Luca Pannone
- Genetics and Rare Diseases Research Division, Ospedale Pediatrico Bambino Gesù, Rome, Italy
| | - Amélie Bonnefond
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille, France
- Université de Lille, CHU de Lille, Lille, France
- Department of Metabolism, Imperial College London, London, UK
| | - Serena Pezzilli
- Research Unit of Metabolic and Cardiovascular Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
- Medical Genetics, University of Chieti, Chieti, Italy
| | - Tommaso Biagini
- Unit of Bioinformatics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
| | | | - Timothy Hastings
- Research Division, Joslin Diabetes Center, and Harvard Medical School, Boston, MA, USA
| | - Christine Mendonca
- Research Division, Joslin Diabetes Center, and Harvard Medical School, Boston, MA, USA
| | - Lorella Marselli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Rosa Di Paola
- Research Unit of Diabetes and Endocrine Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
| | - Zuroida Abubakar
- Cellular and Molecular Biology of Diabetes Research Group, Siriraj Center of Research Excellence for Diabetes and Obesity, Division of Molecular Medicine, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Luana Mercuri
- Research Unit of Metabolic and Cardiovascular Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
| | - Federica Alberico
- Research Unit of Metabolic and Cardiovascular Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
| | - Elisabetta Flex
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Julian Ceròn
- Modeling human diseases in C. elegans. Genes, Diseases and Therapies Program, Bellvitge Biomedical Research Institute – IDIBELL, L’Hospitalet de Llobregat, Barcelona, Spain
| | - Montserrat Porta-de-la-Riva
- Modeling human diseases in C. elegans. Genes, Diseases and Therapies Program, Bellvitge Biomedical Research Institute – IDIBELL, L’Hospitalet de Llobregat, Barcelona, Spain
| | - Ornella Ludovico
- Department of Clinical Sciences, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
| | - Massimo Carella
- Research Unit of Medical Genetics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
| | - Simone Martinelli
- Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Tommaso Mazza
- Unit of Bioinformatics, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
| | - Philippe Froguel
- Inserm UMR1283, CNRS UMR8199, European Genomic Institute for Diabetes (EGID), Institut Pasteur de Lille, Lille, France
- Université de Lille, CHU de Lille, Lille, France
- Department of Metabolism, Imperial College London, London, UK
| | - Vincenzo Trischitta
- Research Unit of Diabetes and Endocrine Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Alessandro Doria
- Research Division, Joslin Diabetes Center, and Harvard Medical School, Boston, MA, USA
- Alessandro Doria, MD, PhD, MPH, Research Division, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA.
| | - Sabrina Prudente
- Research Unit of Metabolic and Cardiovascular Diseases, Fondazione IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo,Italy
- Correspondence: Sabrina Prudente, PhD, Fondazione IRCCS Casa Sollievo della Sofferenza, CSS-Mendel Institute, Viale Regina Margherita 261, 00198 Rome, Italy.
| |
Collapse
|
4
|
Ahmad W, Ebert PR. Suppression of a core metabolic enzyme dihydrolipoamide dehydrogenase ( dld) protects against amyloid beta toxicity in C. elegans model of Alzheimer's disease. Genes Dis 2021; 8:849-866. [PMID: 34522713 PMCID: PMC8427249 DOI: 10.1016/j.gendis.2020.08.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 07/24/2020] [Accepted: 08/14/2020] [Indexed: 01/24/2023] Open
Abstract
A decrease in energy metabolism is associated with Alzheimer's disease (AD), but it is not known whether the observed decrease exacerbates or protects against the disease. The importance of energy metabolism in AD is reinforced by the observation that variants of dihydrolipoamide dehydrogenase (DLD), is genetically linked to late-onset AD. To determine whether DLD is a suitable therapeutic target, we suppressed the dld-1 gene in Caenorhabditis elegans that express human Aβ peptide in either muscles or neurons. Suppression of the dld-1 gene resulted in significant restoration of vitality and function that had been degraded by Aβ pathology. This included protection of neurons and muscles cells. The observed decrease in proteotoxicity was associated with a decrease in the formation of toxic oligomers rather than a decrease in the abundance of the Aβ peptide. The mitochondrial uncoupler, carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), which like dld-1 gene expression inhibits ATP synthesis, had no significant effect on Aβ toxicity. Proteomics data analysis revealed that beneficial effects after dld-1 suppression could be due to change in energy metabolism and activation of the pathways associated with proteasomal degradation, improved cell signaling and longevity. Thus, some features unique to dld-1 gene suppression are responsible for the therapeutic benefit. By direct genetic intervention, we have shown that acute inhibition of dld-1 gene function may be therapeutically beneficial. This result supports the hypothesis that lowering energy metabolism protects against Aβ pathogenicity and that DLD warrants further investigation as a therapeutic target.
Collapse
Affiliation(s)
- Waqar Ahmad
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Paul R. Ebert
- School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| |
Collapse
|
5
|
Schell M, Wardelmann K, Kleinridders A. Untangling the effect of insulin action on brain mitochondria and metabolism. J Neuroendocrinol 2021; 33:e12932. [PMID: 33506556 DOI: 10.1111/jne.12932] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/02/2020] [Accepted: 12/11/2020] [Indexed: 12/25/2022]
Abstract
The regulation of energy homeostasis is controlled by the brain and, besides requiring high amounts of energy, it relies on functional insulin/insulin-like growth factor (IGF)-1 signalling in the central nervous system. This energy is mainly provided by mitochondria in form of ATP. Thus, there is an intricate interplay between mitochondrial function and insulin/IGF-1 action to enable functional brain signalling and, accordingly, propagate a healthy metabolism. To adapt to different nutritional conditions, the brain is able to sense the current energy status via mitochondrial and insulin signalling-dependent pathways and exerts an appropriate metabolic response. However, regional, cell type and receptor-specific consequences of this interaction occur and are linked to diverse outcomes such as altered nutrient sensing, body weight regulation or even cognitive function. Impairments of this cross-talk can lead to obesity and glucose intolerance and are linked to neurodegenerative diseases, yet they also induce a self-sustainable, dysfunctional 'metabolic triangle' characterised by insulin resistance, mitochondrial dysfunction and inflammation in the brain. The identification of causal factors deteriorating insulin action, mitochondrial function and concomitantly a signature of metabolic stress in the brain is of utter importance to offer novel mechanistic insights into development of the continuously rising prevalence of non-communicable diseases such as type 2 diabetes and neurodegeneration. This review aims to determine the effect of insulin action on brain mitochondrial function and energy metabolism. It precisely outlines the interaction and differences between insulin action, insulin-like growth factor (IGF)-1 signalling and mitochondrial function; distinguishes between causality and association; and reveals its consequences for metabolism and cognition. We hypothesise that an improvement of at least one signalling pathway can overcome the vicious cycle of a self-perpetuating metabolic dysfunction in the brain present in metabolic and neurodegenerative diseases.
Collapse
Affiliation(s)
- Mareike Schell
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Kristina Wardelmann
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Department of Molecular and Experimental Nutritional Medicine, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| | - André Kleinridders
- Department of Molecular and Experimental Nutritional Medicine, Institute of Nutritional Science, University of Potsdam, Nuthetal, Germany
| |
Collapse
|
6
|
Podraza-Farhanieh A, Natarajan B, Raj D, Kao G, Naredi P. ENPL-1, the Caenorhabditis elegans homolog of GRP94, promotes insulin secretion via regulation of proinsulin processing and maturation. Development 2020; 147:dev190082. [PMID: 33037039 PMCID: PMC10666919 DOI: 10.1242/dev.190082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 09/28/2020] [Indexed: 12/27/2022]
Abstract
Insulin/IGF signaling in Caenorhabditis elegans is crucial for proper development of the dauer larva and growth control. Mutants disturbing insulin processing, secretion and downstream signaling perturb this process and have helped identify genes that affect progression of type 2 diabetes. Insulin maturation is required for its proper secretion by pancreatic β cells. The role of the endoplasmic reticulum (ER) chaperones in insulin processing and secretion needs further study. We show that the C. elegans ER chaperone ENPL-1/GRP94 (HSP90B1), acts in dauer development by promoting insulin secretion and signaling. Processing of a proinsulin likely involves binding between the two proteins via a specific domain. We show that, in enpl-1 mutants, an unprocessed insulin exits the ER lumen and is found in dense core vesicles, but is not secreted. The high ER stress in enpl-1 mutants does not cause the secretion defect. Importantly, increased ENPL-1 levels result in increased secretion. Taken together, our work indicates that ENPL-1 operates at the level of insulin availability and is an essential modulator of insulin processing and secretion.
Collapse
Affiliation(s)
- Agnieszka Podraza-Farhanieh
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | | | - Dorota Raj
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Gautam Kao
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
| | - Peter Naredi
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE413 45 Gothenburg, Sweden
- Department of Surgery, Sahlgrenska University Hospital, SE413 45 Gothenburg, Sweden
| |
Collapse
|
7
|
Yang W, Shin HY, Cho H, Chung JY, Lee EJ, Kim JH, Kang ES. TOM40 Inhibits Ovarian Cancer Cell Growth by Modulating Mitochondrial Function Including Intracellular ATP and ROS Levels. Cancers (Basel) 2020; 12:cancers12051329. [PMID: 32456076 PMCID: PMC7281007 DOI: 10.3390/cancers12051329] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/12/2020] [Accepted: 05/19/2020] [Indexed: 12/17/2022] Open
Abstract
TOM40 is a channel-forming subunit of translocase, which is essential for the movement of proteins into the mitochondria. We found that TOM40 was highly expressed in epithelial ovarian cancer (EOC) cells at both the transcriptional and translational levels; its expression increased significantly during the transformation from normal ovarian epithelial cells to EOC (p < 0.001), and TOM40 expression negatively correlated with disease-free survival (Hazard ratio = 1.79, 95% Confidence inerval 1.16–2.78, p = 0.009). TOM40 knockdown decreased proliferation in several EOC cell lines and reduced tumor burden in an in vivo xenograft mouse model. TOM40 expression positively correlated with intracellular adenosine triphosphate (ATP) levels. The low ATP and high reactive oxygen species (ROS) levels increased the activity of AMP-activated protein kinase (AMPK) in TOM40 knockdown EOC cells. However, AMPK activity did not correlate with declined cell growth in TOM40 knockdown EOC cells. We found that metformin, first-line therapy for type 2 diabetes, effectively inhibited the growth of EOC cell lines in an AMPK-independent manner by inhibiting mitochondria complex I. In conclusion, TOM40 positively correlated with mitochondrial activities, and its association enhances the proliferation of ovarian cancer. Also, metformin is an effective therapeutic option in TOM40 overexpressed ovarian cancer than normal ovarian epithelium.
Collapse
Affiliation(s)
- Wookyeom Yang
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Ha-Yeon Shin
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Hanbyoul Cho
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Joon-Yong Chung
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Eun-ju Lee
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
| | - Jae-Hoon Kim
- Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea; (W.Y.); (H.-Y.S.); (H.C.); (E.-j.L.)
- Correspondence: (J.-H.K.); (E.-S.K.); Tel.:+82-2-2019-3430 (J.-H.K.); +82-2-3410-2703 (E.-S.K.); Fax: +82-2-3462-8209 (J.-H.K.); +82-2-3410-2719 (E.-S.K.)
| | - Eun-Suk Kang
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
- Correspondence: (J.-H.K.); (E.-S.K.); Tel.:+82-2-2019-3430 (J.-H.K.); +82-2-3410-2703 (E.-S.K.); Fax: +82-2-3462-8209 (J.-H.K.); +82-2-3410-2719 (E.-S.K.)
| |
Collapse
|
8
|
Roy S, Singh M, Sammi SR, Pandey R, Kaithwas G. ALA-mediated biphasic downregulation of α-7nAchR/HIF-1α along with mitochondrial stress modulation strategy in mammary gland chemoprevention. J Cell Physiol 2018; 234:4015-4029. [PMID: 30221357 DOI: 10.1002/jcp.27168] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 07/16/2018] [Indexed: 12/14/2022]
Abstract
The study elucidates the effect of ɑ-linolenic acid (ALA) on mitochondrial stress, hypoxic cancer microenvironment, and intervention of cholinergic anti-inflammatory pathway using N-methyl-N-nitrosourea (MNU) induced estrogen receptor (ER+) mammary gland carcinoma and Caenorhabditis elegans model, respectively. The efficacy of ALA was scrutinized in vivo and in vitro using various experiments like hemodynamic studies, morphological analysis, antioxidants parameters, immunoblotting, and quantitative reverse transcription polymerase chain reaction. The effect of ALA was also validated using C. elegans worms. ALA administration had a positive effect on tissue architecture of the malignancy when scrutinized through the whole mount carmine staining, hematoxylin and eosin staining, and scanning electron microscopy. The proteomic and genomic checkpoint revealed the participation of mitochondrial dysfunction, alteration of hypoxic microenvironment, and involvement of cholinergic anti-inflammatory response after treatment with ALA. ALA treatment has also increased the level of synaptic acetylcholine and acetylcholine esterase with a significant decrease in lipid content. It was concluded that ALA persuaded the mitochondrial stress, activation of downstream cholinergic anti-inflammatory markers, and favorable regulation of hypoxia microenvironment through inhibition of fatty acid synthase and sterol regulatory element-binding protein.
Collapse
Affiliation(s)
- Subhadeep Roy
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Manjari Singh
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Shreesh Raj Sammi
- Department of Microbial Technology and Nematology, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Rakesh Pandey
- Department of Microbial Technology and Nematology, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India
| | - Gaurav Kaithwas
- Department of Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| |
Collapse
|
9
|
Affinity purification of cell-specific mitochondria from whole animals resolves patterns of genetic mosaicism. Nat Cell Biol 2018; 20:352-360. [DOI: 10.1038/s41556-017-0023-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022]
|
10
|
Caenorhabditis elegans AGXT-1 is a mitochondrial and temperature-adapted ortholog of peroxisomal human AGT1: New insights into between-species divergence in glyoxylate metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:1195-1205. [PMID: 27179589 DOI: 10.1016/j.bbapap.2016.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/27/2016] [Accepted: 05/10/2016] [Indexed: 11/23/2022]
|
11
|
Gitschlag BL, Kirby CS, Samuels DC, Gangula RD, Mallal SA, Patel MR. Homeostatic Responses Regulate Selfish Mitochondrial Genome Dynamics in C. elegans. Cell Metab 2016; 24:91-103. [PMID: 27411011 PMCID: PMC5287496 DOI: 10.1016/j.cmet.2016.06.008] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/27/2016] [Accepted: 06/13/2016] [Indexed: 02/08/2023]
Abstract
Mutant mitochondrial genomes (mtDNA) can be viewed as selfish genetic elements that persist in a state of heteroplasmy despite having potentially deleterious metabolic consequences. We sought to study regulation of selfish mtDNA dynamics. We establish that the large 3.1-kb deletion-bearing mtDNA variant uaDf5 is a selfish genome in Caenorhabditis elegans. Next, we show that uaDf5 mutant mtDNA replicates in addition to, not at the expense of, wild-type mtDNA. These data suggest the existence of a homeostatic copy-number control that is exploited by uaDf5 to "hitchhike" to high frequency. We also observe activation of the mitochondrial unfolded protein response (UPR(mt)) in uaDf5 animals. Loss of UPR(mt) causes a decrease in uaDf5 frequency, whereas its constitutive activation increases uaDf5 levels. UPR(mt) activation protects uaDf5 from mitophagy. Taken together, we propose that mtDNA copy-number control and UPR(mt) represent two homeostatic response mechanisms that play important roles in regulating selfish mitochondrial genome dynamics.
Collapse
Affiliation(s)
- Bryan L Gitschlag
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Interdisciplinary Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Cait S Kirby
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Biological Sciences Graduate Program, Vanderbilt University, Nashville, TN 37232, USA
| | - David C Samuels
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Rama D Gangula
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Simon A Mallal
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Institute for Immunology and Infectious Diseases, Murdoch University, Murdoch, WA 6150, Australia
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA.
| |
Collapse
|
12
|
Oláhová M, Veal EA. A peroxiredoxin, PRDX-2, is required for insulin secretion and insulin/IIS-dependent regulation of stress resistance and longevity. Aging Cell 2015; 14:558-68. [PMID: 25808059 PMCID: PMC4531070 DOI: 10.1111/acel.12321] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2014] [Indexed: 12/22/2022] Open
Abstract
Peroxiredoxins (Prx) are abundant thiol peroxidases with a conserved anti-ageing role. In contrast to most animals, the nematode worm, Caenorhabditis elegans, encodes a single cytosolic 2-Cys Prx, PRDX-2, rendering it an excellent model for examining how peroxiredoxins affect animal physiology and ageing. Our previous work revealed that, although PRDX-2 protects against the toxicity of peroxides, enigmatically, prdx-2-mutant animals are hyper-resistant to other forms of oxidative stress. Here, we have investigated the basis for this increased resistance. Mammalian FOXO and Nrf2 transcription factors directly promote the expression of a range of detoxification enzymes. We show that the FOXO orthologue, DAF-16, and the Nrf2 orthologue, SKN-1, are required for the increased stress resistance of prdx-2-mutant worms. Our data suggest that PRDX-2 is required for normal levels of insulin secretion and hence the inhibition of DAF-16 and SKN-1 by insulin/IGF-1-like signalling (IIS) under nutrient-rich conditions. Intriguingly, loss of PRDX-2 increases DAF-16 and SKN-1 activities sufficiently to increase arsenite resistance without initiating other IIS-inhibited processes. Together, these data suggest that loss of peroxiredoxin function may increase stress resistance by reducing insulin secretion, but that further changes in insulin signalling are required for the reprogramming of development and fat metabolism. In addition, we reveal that the temperature-dependent prolongevity function of PRDX-2 is required for the extended lifespan associated with several pathways, including further reductions in IIS.
Collapse
Affiliation(s)
- Monika Oláhová
- Institute for Cell and Molecular Biosciences Newcastle University Framlington Place Newcastle upon Tyne NE2 4HH UK
| | - Elizabeth A. Veal
- Institute for Cell and Molecular Biosciences Newcastle University Framlington Place Newcastle upon Tyne NE2 4HH UK
| |
Collapse
|
13
|
Wolf T, Qi W, Schindler V, Runkel ED, Baumeister R. Doxycyclin ameliorates a starvation-induced germline tumor in C. elegans daf-18/PTEN mutant background. Exp Gerontol 2014; 56:114-22. [PMID: 24746511 DOI: 10.1016/j.exger.2014.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/19/2022]
Abstract
Managing available resources is a key necessity of each organism to cope with the environment. The nematode C. elegans responds to nutritional deprivation or harsh environmental conditions with a multitude of developmental adaptations, among them a starvation-induced quiescence at early larval development (L1). daf-18, the C. elegans homolog of the human tumor suppressor gene PTEN, is essential for the maintenance of survival and germline stem cell arrest during the L1 diapause. We show here that daf-18 mutants, independently to their failure to maintain G2 arrest of the primordial germ cells, develop a gonad phenotype after refeeding. This highly penetrant gonadal phenotype is further enhanced by a mutation in shc-1, encoding a protein homologous to the human adaptor ShcA. Features of this phenotype are a tumor-like phenotype encompassing hyper-proliferation of germ cell nuclei and disruption/invasion of the basement membrane surrounding the gonad. The penetrance of this phenotype is reduced by decreasing starvation temperature. In addition, it is also ameliorated in a dose-dependent way by exposure to the antibiotic doxycyclin either during starvation or during subsequent refeeding. Since, in eukaryotic cells, doxycyclin specifically blocks mitochondrial translation, our results suggest that daf-18 and shc-1;daf-18 mutants fail to adapt mitochondrial activity to reduced nutritional availability during early larval developing.
Collapse
Affiliation(s)
- Tim Wolf
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Wenjing Qi
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Verena Schindler
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Eva Diana Runkel
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, D-79104 Freiburg, Germany
| | - Ralf Baumeister
- Faculty of Biology, Institute of Biology III, Albert-Ludwigs-University, D-79104 Freiburg, Germany; Faculty of Medicine, ZBMZ Centre of Biochemistry and Molecular Cell Research, Albert-Ludwigs-University, D-79104 Freiburg, Germany; BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University, D-79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, D-79104 Freiburg, Germany.
| |
Collapse
|
14
|
Gottschalk WK, Lutz MW, He YT, Saunders AM, Burns DK, Roses AD, Chiba-Falek O. The Broad Impact of TOM40 on Neurodegenerative Diseases in Aging. ACTA ACUST UNITED AC 2014; 1. [PMID: 25745640 DOI: 10.13188/2376-922x.1000003] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mitochondrial dysfunction is an important factor in the pathogenesis of age-related diseases, including neurodegenerative diseases like Alzheimer's and Parkinson's spectrum disorders. A polymorphism in Translocase of the Outer Mitochondrial Membrane - 40 kD (TOMM40) is associated with risk and age-of onset of late-onset AD, and is the only nuclear- encoded gene identified in genetic studies to date that presumably contributes to LOAD-related mitochondria dysfunction. In this review, we describe the TOM40-mediated mitochondrial protein import mechanism, and discuss the evidence linking TOM40 with Alzheimer's (AD) and Parkinson's (PD) diseases. All but 36 of the >~1,500 mitochondrial proteins are encoded by the nucleus and are synthesized on cytoplasmic ribosomes, and most of these are imported into mitochondria through the TOM complex, of which TOM40 is the central pore, mediating communication between the cytoplasm and the mitochondrial interior. APP enters and obstructs the TOM40 pore, inhibiting import of OXPHOS-related proteins and disrupting the mitochondrial redox balance. Other pathogenic proteins, such as Aβ and alpha-synuclein, readily pass through the pore and cause toxic effects by directly inhibiting mitochondrial enzymes. Healthy mitochondria normally import and degrade the PD-related protein Pink1, but Pink1 exits mitochondria if the membrane potential collapses and initiates Parkin-mediated mitophagy. Under normal circumstances, this process helps clear dysfunctional mitochondria and contributes to cellular health, but PINK1 mutations associated with PD exit mitochondria with intact membrane potentials, disrupting mitochondrial dynamics, leading to pathology. Thus, TOM40 plays a central role in the mitochondrial dysfunction that underlies age-related neurodegenerative diseases. Learning about the factors that control TOM40 levels and activity, and how TOM40, specifically, and the TOM complex, generally, interacts with potentially pathogenic proteins, will provide deeper insights to AD and PD pathogenesis, and possibly new targets for preventative and/or therapeutic treatments.
Collapse
Affiliation(s)
- William K Gottschalk
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael W Lutz
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Yu Ting He
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| | - Ann M Saunders
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Zinfandel Pharmaceuticals, Chapel Hill, NC, USA
| | | | - Allen D Roses
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Zinfandel Pharmaceuticals, Chapel Hill, NC, USA
| | - Ornit Chiba-Falek
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA ; Joseph and Kathleen Bryan Alzheimer's Disease Research Center, Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
| |
Collapse
|
15
|
Han SM, El Oussini H, Scekic-Zahirovic J, Vibbert J, Cottee P, Prasain JK, Bellen HJ, Dupuis L, Miller MA. VAPB/ALS8 MSP ligands regulate striated muscle energy metabolism critical for adult survival in caenorhabditis elegans. PLoS Genet 2013; 9:e1003738. [PMID: 24039594 PMCID: PMC3764199 DOI: 10.1371/journal.pgen.1003738] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/08/2013] [Indexed: 12/13/2022] Open
Abstract
Mutations in VAPB/ALS8 are associated with amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), two motor neuron diseases that often include alterations in energy metabolism. We have shown that C. elegans and Drosophila neurons secrete a cleavage product of VAPB, the N-terminal major sperm protein domain (vMSP). Secreted vMSPs signal through Roundabout and Lar-like receptors expressed on striated muscle. The muscle signaling pathway localizes mitochondria to myofilaments, alters their fission/fusion balance, and promotes energy production. Here, we show that neuronal loss of the C. elegans VAPB homolog triggers metabolic alterations that appear to compensate for muscle mitochondrial dysfunction. When vMSP levels drop, cytoskeletal or mitochondrial abnormalities in muscle induce elevated DAF-16, the Forkhead Box O (FoxO) homolog, transcription factor activity. DAF-16 promotes muscle triacylglycerol accumulation, increases ATP levels in adults, and extends lifespan, despite reduced muscle mitochondria electron transport chain activity. Finally, Vapb knock-out mice exhibit abnormal muscular triacylglycerol levels and FoxO target gene transcriptional responses to fasting and refeeding. Our data indicate that impaired vMSP signaling to striated muscle alters FoxO activity, which affects energy metabolism. Abnormalities in energy metabolism of ALS patients may thus constitute a compensatory mechanism counterbalancing skeletal muscle mitochondrial dysfunction.
Collapse
Affiliation(s)
- Sung Min Han
- Department of Cell, Developmental, and Integrative Biology, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
| | - Hajer El Oussini
- INSERM, U1118, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
- Faculté de Médecine, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, UMRS1118, Strasbourg, France
| | - Jelena Scekic-Zahirovic
- INSERM, U1118, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
- Faculté de Médecine, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, UMRS1118, Strasbourg, France
| | - Jack Vibbert
- Department of Cell, Developmental, and Integrative Biology, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
| | - Pauline Cottee
- Department of Cell, Developmental, and Integrative Biology, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
| | - Jeevan K. Prasain
- Department of Pharmacology and Toxicology, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
| | - Hugo J. Bellen
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Luc Dupuis
- INSERM, U1118, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
- Faculté de Médecine, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, UMRS1118, Strasbourg, France
| | - Michael A. Miller
- Department of Cell, Developmental, and Integrative Biology, University of Alabama School of Medicine, Birmingham, Alabama, United States of America
| |
Collapse
|
16
|
Ritter AD, Shen Y, Fuxman Bass J, Jeyaraj S, Deplancke B, Mukhopadhyay A, Xu J, Driscoll M, Tissenbaum HA, Walhout AJM. Complex expression dynamics and robustness in C. elegans insulin networks. Genome Res 2013; 23:954-65. [PMID: 23539137 PMCID: PMC3668363 DOI: 10.1101/gr.150466.112] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Gene families expand by gene duplication, and resulting paralogs diverge through mutation. Functional diversification can include neofunctionalization as well as subfunctionalization of ancestral functions. In addition, redundancy in which multiple genes fulfill overlapping functions is often maintained. Here, we use the family of 40 Caenorhabditis elegans insulins to gain insight into the balance between specificity and redundancy. The insulin/insulin-like growth factor (IIS) pathway comprises a single receptor, DAF-2. To date, no single insulin-like peptide recapitulates all DAF-2-associated phenotypes, likely due to redundancy between insulin-like genes. To provide a first-level annotation of potential patterns of redundancy, we comprehensively delineate the spatiotemporal and conditional expression of all 40 insulins in living animals. We observe extensive dynamics in expression that can explain the lack of simple patterns of pairwise redundancy. We propose a model in which gene families evolve to attain differential alliances in different tissues and in response to a range of environmental stresses.
Collapse
Affiliation(s)
- Ashlyn D Ritter
- Program in Systems Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Williams MJ, Almén MS, Fredriksson R, Schiöth HB. What model organisms and interactomics can reveal about the genetics of human obesity. Cell Mol Life Sci 2012; 69:3819-34. [PMID: 22618246 PMCID: PMC11114734 DOI: 10.1007/s00018-012-1022-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/22/2012] [Accepted: 05/02/2012] [Indexed: 01/05/2023]
Abstract
Genome-wide association studies have identified a number of genes associated with human body weight. While some of these genes are large fields within obesity research, such as MC4R, POMC, FTO and BDNF, the majority do not have a clearly defined functional role explaining why they may affect body weight. Here, we searched biological databases and discovered 33 additional genes associated with human obesity (CADM2, GIPR, GPCR5B, LRP1B, NEGR1, NRXN3, SH2B1, FANCL, GNPDA2, HMGCR, MAP2K5, NUDT3, PRKD1, QPCTL, TNNI3K, MTCH2, DNAJC27, SLC39A8, MTIF3, RPL27A, SEC16B, ETV5, HMGA1, TFAP2B, TUB, ZNF608, FAIM2, KCTD15, LINGO2, POC5, PTBP2, TMEM18, TMEM160). We find that the majority have orthologues in distant species, such as D. melanogaster and C. elegans, suggesting that they are important for the biology of most bilateral species. Intriguingly, signalling cascade genes and transcription factors are enriched among these obesity genes, and several of the genes show properties that could be useful for potential drug discovery. In this review, we demonstrate how information from several distant model species, interactomics and signalling pathway analysis represents an important way to better understand the functional diversity of the surprisingly high number of molecules that seem to be important for human obesity.
Collapse
Affiliation(s)
- Michael J. Williams
- Department of Neuroscience, Functional Pharmacology, Biomedical Center, Uppsala University, Box 593, 75 124 Uppsala, Sweden
| | - Markus S. Almén
- Department of Neuroscience, Functional Pharmacology, Biomedical Center, Uppsala University, Box 593, 75 124 Uppsala, Sweden
| | - Robert Fredriksson
- Department of Neuroscience, Functional Pharmacology, Biomedical Center, Uppsala University, Box 593, 75 124 Uppsala, Sweden
| | - Helgi B. Schiöth
- Department of Neuroscience, Functional Pharmacology, Biomedical Center, Uppsala University, Box 593, 75 124 Uppsala, Sweden
| |
Collapse
|
18
|
Billing O, Natarajan B, Mohammed A, Naredi P, Kao G. A directed RNAi screen based on larval growth arrest reveals new modifiers of C. elegans insulin signaling. PLoS One 2012; 7:e34507. [PMID: 22511947 PMCID: PMC3325266 DOI: 10.1371/journal.pone.0034507] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 03/06/2012] [Indexed: 01/03/2023] Open
Abstract
Genes regulating Caenorhabditis elegans insulin/IGF signaling (IIS) have largely been identified on the basis of their involvement in dauer development or longevity. A third IIS phenotype is the first larval stage (L1) diapause, which is also influenced by asna-1, a regulator of DAF-28/insulin secretion. We reasoned that new regulators of IIS strength might be identified in screens based on the L1 diapause and the asna-1 phenotype. Eighty- six genes were selected for analysis by virtue of their predicted interaction with ASNA-1 and screened for asna-1-like larval arrest. ykt-6, mrps-2, mrps-10 and mrpl-43 were identified as genes which, when inactivated, caused larval arrest without any associated feeding defects. Several tests indicated that IIS strength was weaker and that insulin secretion was defective in these animals. This study highlights the role of the Golgi network and the mitochondria in insulin secretion and provides a new list of genes that modulate IIS in C. elegans.
Collapse
Affiliation(s)
- Ola Billing
- Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden
| | | | | | - Peter Naredi
- Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden
- * E-mail: (PN); (GK)
| | - Gautam Kao
- Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden
- * E-mail: (PN); (GK)
| |
Collapse
|
19
|
Inflammation and cellular stress: a mechanistic link between immune-mediated and metabolically driven pathologies. Eur J Nutr 2011; 50:219-33. [PMID: 21547407 DOI: 10.1007/s00394-011-0197-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Accepted: 04/04/2011] [Indexed: 12/21/2022]
Abstract
BACKGROUND Multiple cellular stress responses have been implicated in chronic diseases such as obesity, diabetes, cardiovascular, and inflammatory bowel diseases. Even though phenotypically different, chronic diseases share cellular stress signaling pathways, in particular endoplasmic reticulum (ER) unfolded protein response (UPR). RESULTS AND METHODS The purpose of the ER UPR is to restore ER homeostasis after challenges of the ER function. Among the triggers of ER UPR are changes in the redox status, elevated protein synthesis, accumulation of unfolded or misfolded proteins, energy deficiency and glucose deprivation, cholesterol depletion, and microbial signals. Numerous mouse models have been used to characterize the contribution of ER UPR to several pathologies, and ER UPR-associated signaling has also been demonstrated to be relevant in humans. Additionally, recent evidence suggests that the ER UPR is interrelated with metabolic and inflammatory pathways, autophagy, apoptosis, and mitochondrial stress signaling. Furthermore, microbial as well as nutrient sensing is integrated into the ER-associated signaling network. CONCLUSION The data discussed in the present review highlight the interaction of ER UPR with inflammatory pathways, metabolic processes and mitochondrial function, and their interrelation in the context of chronic diseases.
Collapse
|