1
|
Hernandez-Cravero B, Gallino S, Florman J, Vranych C, Diaz P, Elgoyhen AB, Alkema MJ, de Mendoza D. Cannabinoids activate the insulin pathway to modulate mobilization of cholesterol in C. elegans. PLoS Genet 2022; 18:e1010346. [PMID: 36346800 PMCID: PMC9674138 DOI: 10.1371/journal.pgen.1010346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 11/18/2022] [Accepted: 10/31/2022] [Indexed: 11/10/2022] Open
Abstract
The nematode Caenorhabditis elegans requires exogenous cholesterol to survive and its depletion leads to early developmental arrest. Thus, tight regulation of cholesterol storage and distribution within the organism is critical. Previously, we demonstrated that the endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) plays a key role in C. elegans since it modulates sterol mobilization. However, the mechanism remains unknown. Here we show that mutations in the ocr-2 and osm-9 genes, coding for transient receptors potential V (TRPV) ion channels, dramatically reduce the effect of 2-AG in cholesterol mobilization. Through genetic analysis in combination with the rescue of larval arrest induced by sterol starvation, we found that the insulin/IGF-1signaling (IIS) pathway and UNC-31/CAPS, a calcium-activated regulator of neural dense-core vesicles release, are essential for 2-AG-mediated stimulation of cholesterol mobilization. These findings indicate that 2-AG-dependent cholesterol trafficking requires the release of insulin peptides and signaling through the DAF-2 insulin receptor. These results suggest that 2-AG acts as an endogenous modulator of TRPV signal transduction to control intracellular sterol trafficking through modulation of the IGF-1 signaling pathway
Collapse
Affiliation(s)
- Bruno Hernandez-Cravero
- Laboratorio de Fisiología Microbiana, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Sofia Gallino
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), CONICET, Buenos Aires, Argentina
| | - Jeremy Florman
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Cecilia Vranych
- Laboratorio de Fisiología Microbiana, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Philippe Diaz
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana, United States of America
| | - Ana Belén Elgoyhen
- Laboratorio de Fisiología y Genética de la Audición, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres" (INGEBI), CONICET, Buenos Aires, Argentina
| | - Mark J. Alkema
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Diego de Mendoza
- Laboratorio de Fisiología Microbiana, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
- * E-mail:
| |
Collapse
|
2
|
Wang Y, Sun Y, Zhang Z, Li Z, Zhang H, Liao Y, Tang C, Cai P. Enhancement in the ATP level and antioxidant capacity of Caenorhabditis elegans under continuous exposure to extremely low-frequency electromagnetic field for multiple generations. Int J Radiat Biol 2020; 96:1633-1640. [PMID: 32991227 DOI: 10.1080/09553002.2020.1828657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE Safety concerns about the effects of long-term extremely low-frequency electromagnetic field (ELF-EMF) exposure on human health have been raised. To explore the effects of continuous exposure to ELF-EMF on organisms for multiple generations, we selected Caenorhabditis elegans as a model organism and conducted long-term continuous exposure studies for multiple generations under 20 °C, 50 Hz, and 3 mT ELF-EMF. MATERIALS AND METHODS Each generation of worms was treated with ELF-EMF from the egg in the same environment. After long-term exposure to ELF-EMF, the body length of the worms was detected, and 15th generation adult worms were selected as the research object. The ATP level and ATPase were detected, and the expression levels of genes encoding ATP synthase (r53.4, hpo-18, atp-5, unc-32, atp-3) were detected by RT-PCR. In worm's antioxidant system, the level of reactive oxygen species (ROS) was detected by dichlorofluorescein staining, and the total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and catalase (CAT) activity were investigated. The expression of genes encoding superoxide dismutase (sod-1, sod-2, sod-3) was detected in adult (60 h) worms of the fifteenth generation (F15). RESULTS These results showed that the body length of F15 worms increased significantly, ATP content increased significantly, ATP synthase activity was significantly enhanced, and the expression levels of the r53.4, hpo-18, atp-5, and atp-3 genes encoding ATPase were significantly upregulated in F15 worms. In addition, SOD activity increased significantly, and the expression levels of the sod-1, sod-2, and sod-3 genes encoding SOD were also significantly upregulated in F15 worms. CONCLUSIONS These results indicated that continuous exposure to 50 Hz, 3 mT ELF-EMF for multiple generations can increase the body length of worms, induce the synthesis of ATP and enhance the antioxidant capacity of worms.
Collapse
Affiliation(s)
- Yahong Wang
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China
| | - Yongyan Sun
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.,Tianjin Key Laboratory of Hazardous Waste Safety Disposal and Recycling Technology, Tianjin University of Technology, Tianjin, China
| | - Ziyan Zhang
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China.,Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Zhihui Li
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China
| | - Hongying Zhang
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China
| | - Yanyan Liao
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China
| | - Chao Tang
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China
| | - Peng Cai
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,Xiamen Key Laboratory of Physical Environment, Xiamen, China.,Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
3
|
De la Parra-Guerra A, Stürzenbaum S, Olivero-Verbel J. Intergenerational toxicity of nonylphenol ethoxylate (NP-9) in Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 197:110588. [PMID: 32289633 DOI: 10.1016/j.ecoenv.2020.110588] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/22/2020] [Accepted: 04/01/2020] [Indexed: 05/24/2023]
Abstract
The ethoxylated isomers of nonylphenol (NPEs, NP-9) are one of the main active ingredients present in nonionic surfactants employed as herbicides, cosmetics, paints, plastics, disinfectants and detergents. These chemicals and their metabolites are commonly found in environmental matrices. The aim of this work was to evaluate the intergenerational toxicity of NP-9 in Caenorhabditis elegans. The lethality, length, width, locomotion and lifespan were investigated in the larval stage L4 of the wild strain N2. Transgenic green fluorescent protein (GFP) strains were employed to estimate changes in relative gene expression. RT-qPCR was utilized to measure mRNA expression for neurotoxicity-related genes (unc-30, unc-25, dop-3, dat-1, mgl-1, and eat-4). Data were obtained from parent worms (P0) and the first generation (F1). Lethality of the nematode was concentration-dependent, with 48 h-LC50 values of 3215 and 1983 μM in P0 and F1, respectively. Non-lethal concentrations of NP-9 reduced locomotion. Lifespan was also decreased by the xenobiotic, but the negative effect was greater in P0 than in F1. Non-monotonic concentration-response curves were observed for body length and width in both generations. The gene expression profile in P0 was different from that registered in F1, although the expression of sod-4, hsp-70, gpx-6 and mtl-2 increased with the surfactant concentration in both generations. None of the tested genes followed a classical concentration-neurotoxicity relationship. In P0, dopamine presented an inverted-U curve, while GABA and glutamate displayed a bimodal type. However, in F1, inverted U-shaped curves were revealed for these genes. In summary, NP-9 induced intergenerational responses in C. elegans through mechanisms involving ROS, and alterations of the GABA, glutamate, and dopamine pathways.
Collapse
Affiliation(s)
- Ana De la Parra-Guerra
- Environmental and Computational Chemistry Group, University of Cartagena, Cartagena, Colombia.
| | - Stephen Stürzenbaum
- School of Population Health & Environmental Sciences, Faculty of Life Science & Medicine, King's College London, London, UK.
| | - Jesus Olivero-Verbel
- Environmental and Computational Chemistry Group, University of Cartagena, Cartagena, Colombia.
| |
Collapse
|
4
|
Zhang X, Chen J, Wu D, Li J, Tyagi RD, Surampalli RY. Economical lipid production from Trichosporon oleaginosus via dissolved oxygen adjustment and crude glycerol addition. BIORESOURCE TECHNOLOGY 2019; 273:288-296. [PMID: 30448680 DOI: 10.1016/j.biortech.2018.11.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
The effect of dissolved oxygen concentration on lipid accumulation in Trichosporon oleaginosus has been investigated. The experiment was performed in 15 L fermenters. The dissolved oxygen concentration varied by adjusting the agitation and aeration. High dissolved oxygen level at 50%-60% enhanced cell growth. Maintaining low dissolved oxygen concentration at 20%-30% during lipogenesis phase led to high final lipid content (51%) in Trichosporon oleaginosus. The consumptions of energy and cost of the process were evaluated. The energy consumption in the dissolved oxygen level optimized process was 41% less than that with dissolved oxygen level at 50%-60%. In addition, the cost was also reduced around one time in the dissolved oxygen level optimized process compared to the one with dissolved oxygen level at 50%-60%. The study provided a feasible way of enhancing lipid accumulation in Trichosporon oleaginosus and reducing the consumption of energy and cost of lipid production from Trichosporon oleaginosus.
Collapse
Affiliation(s)
- Xiaolei Zhang
- Department of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, PR China
| | - Jiaxin Chen
- Department of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, PR China
| | - Di Wu
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong
| | - Ji Li
- Department of Civil and Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen, Guangdong 518055, PR China.
| | | | - Rao Y Surampalli
- Department of Civil Engineering, University of Nebraska-Lincoln, N104 SEC PO Box 886105 Lincoln, NE 68588-6105, USA
| |
Collapse
|
5
|
Rhoads TW, Prasad A, Kwiecien NW, Merrill AE, Zawack K, Westphall MS, Schroeder FC, Kimble J, Coon JJ. NeuCode Labeling in Nematodes: Proteomic and Phosphoproteomic Impact of Ascaroside Treatment in Caenorhabditis elegans. Mol Cell Proteomics 2015; 14:2922-35. [PMID: 26392051 DOI: 10.1074/mcp.m115.049684] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Indexed: 01/05/2023] Open
Abstract
The nematode Caenorhabditis elegans is an important model organism for biomedical research. We previously described NeuCode stable isotope labeling by amino acids in cell culture (SILAC), a method for accurate proteome quantification with potential for multiplexing beyond the limits of traditional stable isotope labeling by amino acids in cell culture. Here we apply NeuCode SILAC to profile the proteomic and phosphoproteomic response of C. elegans to two potent members of the ascaroside family of nematode pheromones. By consuming labeled E. coli as part of their diet, C. elegans nematodes quickly and easily incorporate the NeuCode heavy lysine isotopologues by the young adult stage. Using this approach, we report, at high confidence, one of the largest proteomic and phosphoproteomic data sets to date in C. elegans: 6596 proteins at a false discovery rate ≤ 1% and 6620 phosphorylation isoforms with localization probability ≥75%. Our data reveal a post-translational signature of pheromone sensing that includes many conserved proteins implicated in longevity and response to stress.
Collapse
Affiliation(s)
| | - Aman Prasad
- ‖Biochemistry, and **Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | | | | | - Kelson Zawack
- ‡‡Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853
| | | | - Frank C Schroeder
- ‡‡Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853
| | - Judith Kimble
- ‖Biochemistry, and **Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, 53706
| | - Joshua J Coon
- From the Departments of ‡Chemistry, §Biomolecular Chemistry, ¶Genome Center,
| |
Collapse
|
6
|
Zhang Z, Wang Y, Yan S, Du F, Yan SS. NR2B-dependent cyclophilin D translocation suppresses the recovery of synaptic transmission after oxygen-glucose deprivation. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2225-2234. [PMID: 26232180 DOI: 10.1016/j.bbadis.2015.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 07/24/2015] [Accepted: 07/27/2015] [Indexed: 02/08/2023]
Abstract
N-methyl d-aspartate receptor (NMDA) subunit 2B (NR2B)-containing NMDA receptors and mitochondrial protein cyclophilin D (CypD) are well characterized in mediating neuronal death after ischemia, respectively. However, whether and how NR2B and CypD work together in mediating synaptic injury after ischemia remains elusive. Using an ex vivo ischemia model of oxygen-glucose deprivation (OGD) in hippocampal slices, we identified a NR2B-dependent mechanism for CypD translocation onto the mitochondrial inner membrane. CypD depletion (CypD null mice) prevented OGD-induced impairment in synaptic transmission recovery. Overexpression of neuronal CypD mice (CypD+) exacerbated OGD-induced loss of synaptic transmission. Inhibition of CypD-dependent mitochondrial permeability transition pore (mPTP) opening by cyclosporine A (CSA) attenuated ischemia-induced synaptic perturbation in CypD+ and non-transgenic (non-Tg) mice. The treatment of antioxidant EUK134 to suppress mitochondrial oxidative stress rescued CypD-mediated synaptic dysfunction following OGD in CypD+ slices. Furthermore, OGD provoked the interaction of CypD with P53, which was enhanced in slices overexpressing CypD but was diminished in CypD-null slices. Inhibition of p53 using a specific inhibitor of p53 (pifithrin-μ) attenuated the CypD/p53 interaction following OGD, along with a restored synaptic transmission in both non-Tg and CypD+ hippocampal slices. Our results indicate that OGD-induced CypD translocation potentiates CypD/P53 interaction in a NR2B dependent manner, promoting oxidative stress and loss of synaptic transmission. We also evaluate a new ex vivo chronic OGD-induced ischemia model for studying the effect of oxidative stress on synaptic damage.
Collapse
Affiliation(s)
- Zhihua Zhang
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, University of Kansas, Lawrence, KS 66045
| | - Yongfu Wang
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, University of Kansas, Lawrence, KS 66045
| | - Shijun Yan
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, University of Kansas, Lawrence, KS 66045
| | - Fang Du
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, University of Kansas, Lawrence, KS 66045
| | - Shirley Shidu Yan
- Department of Pharmacology and Toxicology, and Higuchi Bioscience Center, University of Kansas, Lawrence, KS 66045
| |
Collapse
|
7
|
Iranon NN, Miller DL. Interactions between oxygen homeostasis, food availability, and hydrogen sulfide signaling. Front Genet 2012; 3:257. [PMID: 23233860 PMCID: PMC3516179 DOI: 10.3389/fgene.2012.00257] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/04/2012] [Indexed: 12/19/2022] Open
Abstract
The ability to sense and respond to stressful conditions is essential to maintain organismal homeostasis. It has long been recognized that stress response factors that improve survival in changing conditions can also influence longevity. In this review, we discuss different strategies used by animals in response to decreased O(2) (hypoxia) to maintain O(2) homeostasis, and consider interactions between hypoxia responses, nutritional status, and H(2)S signaling. O(2) is an essential environmental nutrient for almost all metazoans as it plays a fundamental role in development and cellular metabolism. However, the physiological response(s) to hypoxia depend greatly on the amount of O(2) available. Animals must sense declining O(2) availability to coordinate fundamental metabolic and signaling pathways. It is not surprising that factors involved in the response to hypoxia are also involved in responding to other key environmental signals, particularly food availability. Recent studies in mammals have also shown that the small gaseous signaling molecule hydrogen sulfide (H(2)S) protects against cellular damage and death in hypoxia. These results suggest that H(2)S signaling also integrates with hypoxia response(s). Many of the signaling pathways that mediate the effects of hypoxia, food deprivation, and H(2)S signaling have also been implicated in the control of lifespan. Understanding how these pathways are coordinated therefore has the potential to reveal new cellular and organismal homeostatic mechanisms that contribute to longevity assurance in animals.
Collapse
Affiliation(s)
- Nicole N Iranon
- Department of Biochemistry, University of Washington School of Medicine Seattle, WA, USA ; Molecular and Cellular Biology Graduate Program, University of Washington School of Medicine Seattle, WA, USA
| | | |
Collapse
|
8
|
Taghibiglou C, Lu J, Mackenzie IR, Wang YT, Cashman NR. Sterol regulatory element binding protein-1 (SREBP1) activation in motor neurons in excitotoxicity and amyotrophic lateral sclerosis (ALS): Indip, a potential therapeutic peptide. Biochem Biophys Res Commun 2011; 413:159-63. [PMID: 21871872 DOI: 10.1016/j.bbrc.2011.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 08/04/2011] [Indexed: 12/31/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of motor neurons in which glutamatergic excitotoxicity may participate. A recently characterized downstream effector of glutamatergic excitotoxicity is the activation of the lipid transcription factor sterol regulatory element binding protein-1 (SREBP1). Here we report that in spinal cord tissues of transgenic mouse model, G93A, as well as post-mortem spinal cord specimens of human familial and sporadic ALS, significant activation of SREBP1 following drastic degradation of ER membrane resident protein Insig-1. A TAT-fused short peptide (Indip) to prevent Insig-1 degradation and subsequent SREBP1 activation significantly protected cultured spinal cord neurons against glutamate-induced excitotoxicity. Indip or other SREBP1-pathway modulating compounds may prove beneficial in ALS.
Collapse
|
9
|
Powell-Coffman JA. Hypoxia signaling and resistance in C. elegans. Trends Endocrinol Metab 2010; 21:435-40. [PMID: 20335046 DOI: 10.1016/j.tem.2010.02.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 02/14/2010] [Accepted: 02/18/2010] [Indexed: 11/20/2022]
Abstract
In normal development and homeostasis and in many disease states, cells and tissues must overcome the challenge of oxygen deprivation (hypoxia). The nematode C. elegans is emerging as an increasingly powerful system in which to understand how animals adapt to moderate hypoxia and survive extreme hypoxic insults. This review provides an overview of C. elegans responses to hypoxia, ranging from adaptation and arrest to death, and highlights some of the recent studies that have provided important insights into hypoxia signaling and resistance. Many of the key genes and pathways are evolutionarily conserved, and C. elegans hypoxia research promises to inform our understanding of oxygen-sensitive signaling and survival in mammalian development and disease.
Collapse
Affiliation(s)
- Jo Anne Powell-Coffman
- Genetics, Development, and Cell Biology Department, Iowa State University, Ames, IA 50011, USA.
| |
Collapse
|
10
|
Osborne TF, Espenshade PJ. Evolutionary conservation and adaptation in the mechanism that regulates SREBP action: what a long, strange tRIP it's been. Genes Dev 2009; 23:2578-91. [PMID: 19933148 DOI: 10.1101/gad.1854309] [Citation(s) in RCA: 197] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sterol regulatory element-binding proteins (SREBPs) are a subfamily of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors that are conserved from fungi to humans and are defined by two key features: a signature tyrosine residue in the DNA-binding domain, and a membrane-tethering domain that is a target for regulated proteolysis. Recent studies including genome-wide and model organism approaches indicate SREBPs coordinate cellular lipid metabolism with other cellular physiologic processes. These functions are broadly related as cellular adaptation to environmental changes ranging from nutrient fluctuations to toxin exposure. This review integrates classic features of the SREBP pathway with newer information regarding the regulation and sensing mechanisms that serve to assimilate different cellular physiologic processes for optimal function and growth.
Collapse
Affiliation(s)
- Timothy F Osborne
- Department of Molecular Biology and Biochemistry, University of California at Irvine, Irvine, California 92697, USA.
| | | |
Collapse
|
11
|
Role of NMDA receptor-dependent activation of SREBP1 in excitotoxic and ischemic neuronal injuries. Nat Med 2009; 15:1399-406. [PMID: 19966780 DOI: 10.1038/nm.2064] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Accepted: 10/28/2009] [Indexed: 02/07/2023]
Abstract
Excitotoxic neuronal damage caused by overactivation of N-methyl-D-aspartate glutamate receptors (NMDARs) is thought to be a principal cause of neuronal loss after stroke and brain trauma. Here we report that activation of sterol regulatory element binding protein-1 (SREBP-1) transcription factor in affected neurons is an essential step in NMDAR-mediated excitotoxic neuronal death in both in vitro and in vivo models of stroke. The NMDAR-mediated activation of SREBP-1 is a result of increased insulin-induced gene-1 (Insig-1) degradation, which can be inhibited with an Insig-1-derived interference peptide (Indip) that we have developed. Using a focal ischemia model of stroke, we show that systemic administration of Indip not only prevents SREBP-1 activation but also substantially reduces neuronal damage and improves behavioral outcome. Our study suggests that agents that reduce SREBP-1 activation such as Indip may represent a new class of neuroprotective therapeutics against stroke.
Collapse
|
12
|
Nomura T, Horikawa M, Shimamura S, Hashimoto T, Sakamoto K. Fat accumulation in Caenorhabditis elegans is mediated by SREBP homolog SBP-1. GENES AND NUTRITION 2009; 5:17-27. [PMID: 19936816 DOI: 10.1007/s12263-009-0157-y] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Accepted: 10/22/2009] [Indexed: 11/30/2022]
Abstract
Research into the metabolism of fats may reveal potential targets for developing pharmaceutical approaches to obesity and related disorders. Such research may be limited, however, by the cost and time involved in using mammalian subjects or developing suitable cell lines. To determine whether invertebrates could be used to carry out such research more efficiently, we investigated the ability of Caenorhabditis elegans (C. elegans) to accumulate body fat following the consumption of excess calories and the mechanisms it uses to metabolize fat. C. elegans worms were grown on media containing various sugars and monitored for changes in body fat and expression of sbp-1, a homolog of the mammalian transcription factor SREBP-1c, which facilitates fat storage in mammals. The fat content increased markedly in worms exposed to glucose. In situ analysis of gene expression in transgenic worms carrying the GFP-labeled promoter region of sbp-1 revealed that sbp-1 mRNA was strongly expressed in the intestine. An sbp-1 knockdown caused a reduction in body size, fat storage, and egg-laying activity. RT-PCR analysis revealed a considerable decrease in the expression of fatty acid synthetic genes (including elo-2, fat-2, and fat-5) and a considerable increase of starvation-inducible gene acs-2. Normal egg-laying activity and acs-2 expression were restored on exposure to a polyunsaturated fatty acid. These findings suggest that SBP-1 and SREBP regulate the amount and composition of fat and response to starvation in a similar manner. Thus, C. elegans may be an appropriate subject for studying the metabolism of fats.
Collapse
Affiliation(s)
- Toshihisa Nomura
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki Japan
| | | | | | | | | |
Collapse
|