1
|
Miyamoto T, Hedjazi S, Miyamoto C, Amrein H. Drosophila neuronal Glucose-6-Phosphatase is a modulator of neuropeptide release that regulates muscle glycogen stores via FMRFamide signaling. Proc Natl Acad Sci U S A 2024; 121:e2319958121. [PMID: 39008673 PMCID: PMC11287260 DOI: 10.1073/pnas.2319958121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 06/07/2024] [Indexed: 07/17/2024] Open
Abstract
Neuropeptides (NPs) and their cognate receptors are critical effectors of diverse physiological processes and behaviors. We recently reported of a noncanonical function of the Drosophila Glucose-6-Phosphatase (G6P) gene in a subset of neurosecretory cells in the central nervous system that governs systemic glucose homeostasis in food-deprived flies. Here, we show that G6P-expressing neurons define six groups of NP-secreting cells, four in the brain and two in the thoracic ganglion. Using the glucose homeostasis phenotype as a screening tool, we find that neurons located in the thoracic ganglion expressing FMRFamide NPs (FMRFaG6P neurons) are necessary and sufficient to maintain systemic glucose homeostasis in starved flies. We further show that G6P is essential in FMRFaG6P neurons for attaining a prominent Golgi apparatus and secreting NPs efficiently. Finally, we establish that G6P-dependent FMRFa signaling is essential for the build-up of glycogen stores in the jump muscle which expresses the receptor for FMRFamides. We propose a general model in which the main role of G6P is to counteract glycolysis in peptidergic neurons for the purpose of optimizing the intracellular environment best suited for the expansion of the Golgi apparatus, boosting release of NPs and enhancing signaling to respective target tissues expressing cognate receptors.
Collapse
Affiliation(s)
- Tetsuya Miyamoto
- Department of Cell Biology and Genetics, School of Medicine, Texas A&M University, Bryan, TX77807
| | - Sheida Hedjazi
- Department of Cell Biology and Genetics, School of Medicine, Texas A&M University, Bryan, TX77807
| | - Chika Miyamoto
- Department of Cell Biology and Genetics, School of Medicine, Texas A&M University, Bryan, TX77807
| | - Hubert Amrein
- Department of Cell Biology and Genetics, School of Medicine, Texas A&M University, Bryan, TX77807
| |
Collapse
|
2
|
Musselman LP, Truong HG, DiAngelo JR. Transcriptional Control of Lipid Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024. [PMID: 38782870 DOI: 10.1007/5584_2024_808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Transcriptional control of lipid metabolism uses a framework that parallels the control of lipid metabolism at the protein or enzyme level, via feedback and feed-forward mechanisms. Increasing the substrates for an enzyme often increases enzyme gene expression, for example. A paucity of product can likewise potentiate transcription or stability of the mRNA encoding the enzyme or enzymes needed to produce it. In addition, changes in second messengers or cellular energy charge can act as on/off switches for transcriptional regulators to control transcript (and protein) abundance. Insects use a wide range of DNA-binding transcription factors (TFs) that sense changes in the cell and its environment to produce the appropriate change in transcription at gene promoters. These TFs work together with histones, spliceosomes, and additional RNA processing factors to ultimately regulate lipid metabolism. In this chapter, we will first focus on the important TFs that control lipid metabolism in insects. Next, we will describe non-TF regulators of insect lipid metabolism such as enzymes that modify acetylation and methylation status, transcriptional coactivators, splicing factors, and microRNAs. To conclude, we consider future goals for studying the mechanisms underlying the control of lipid metabolism in insects.
Collapse
Affiliation(s)
- Laura Palanker Musselman
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY, USA
| | - Huy G Truong
- Division of Science, Pennsylvania State University, Berks Campus, Reading, PA, USA
| | - Justin R DiAngelo
- Division of Science, Pennsylvania State University, Berks Campus, Reading, PA, USA.
| |
Collapse
|
3
|
Miyamoto T, Hedjazi S, Miyamoto C, Amrein H. Drosophila Neuronal Glucose 6 Phosphatase is a Modulator of Neuropeptide Release that Regulates Muscle Glycogen Stores via FMRFamide Signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.11.28.568950. [PMID: 38077084 PMCID: PMC10705280 DOI: 10.1101/2023.11.28.568950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
Neuropeptides (NPs) and their cognate receptors are critical effectors of diverse physiological processes and behaviors. We recently reported of a non-canonical function of the Drosophila Glucose-6-Phosphatase ( G6P ) gene in a subset of neurosecretory cells in the CNS that governs systemic glucose homeostasis in food deprived flies. Here, we show that G6P expressing neurons define 6 groups of neuropeptide secreting cells, 4 in the brain and 2 in the thoracic ganglion. Using the glucose homeostasis phenotype as a screening tool, we find that neurons located in the thoracic ganglion expressing FMRFamide neuropeptides ( FMRFa G6P neurons) are necessary and sufficient to maintain systemic glucose homeostasis in starved flies. We further show that G6P is essential in FMRFa G6P neurons for attaining a prominent Golgi apparatus and secreting neuropeptides efficiently. Finally, we establish that G6P dependent FMRFa signaling is essential for the build-up of glycogen stores in the jump muscle which expresses the receptor for FMRFamides. We propose a general model in which the main role of G6P is to counteract glycolysis in peptidergic neurons for the purpose of optimizing the intracellular environment best suited for the expansion of the Golgi apparatus, boosting release of neuropeptides and enhancing signaling to respective target tissues expressing cognate receptors. SIGNIFICANCE STATEMENT Glucose-6-phosphtase (G6P) is a critical enzyme in sugar synthesis and catalyzes the final step in glucose production. In Drosophila - and insects in general - where trehalose is the circulating sugar and Trehalose phosphate synthase, and not G6P, is used for sugar production, G6P has adopted a novel and unique role in peptidergic neurons in the CNS. Interestingly, flies lacking G6P show diminished Neuropeptide secretions and have a smaller Golgi apparatus in peptidergic neurons. It is hypothesized that the role of G6P is to counteract glycolysis, thereby creating a cellular environment that is more amenable to efficient neuropeptide secretion.
Collapse
|
4
|
Bresgen N, Kovacs M, Lahnsteiner A, Felder TK, Rinnerthaler M. The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective. Biomolecules 2023; 13:912. [PMID: 37371492 DOI: 10.3390/biom13060912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/22/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.
Collapse
Affiliation(s)
- Nikolaus Bresgen
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Melanie Kovacs
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Angelika Lahnsteiner
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Thomas Klaus Felder
- Department of Laboratory Medicine, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Mark Rinnerthaler
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| |
Collapse
|
5
|
Li X, Karpac J. Adaptive physiology drives ageing plasticity in locusts. Nat Ecol Evol 2023:10.1038/s41559-023-02052-6. [PMID: 37156890 DOI: 10.1038/s41559-023-02052-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Affiliation(s)
- Xiaotong Li
- Department of Cell Biology and Genetics, Texas A&M University, School of Medicine, Bryan, TX, USA
| | - Jason Karpac
- Department of Cell Biology and Genetics, Texas A&M University, School of Medicine, Bryan, TX, USA.
| |
Collapse
|
6
|
Braz V, Selim L, Gomes G, Costa ML, Mermelstein C, Gondim KC. Blood meal digestion and changes in lipid reserves are associated with the post-ecdysis development of the flight muscle and ovary in young adults of Rhodnius prolixus. JOURNAL OF INSECT PHYSIOLOGY 2023; 146:104492. [PMID: 36801397 DOI: 10.1016/j.jinsphys.2023.104492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/03/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Rhodnius prolixus is a hemimetabolous, hematophagous insect, and both nymphs and adults feed exclusively on blood. The blood feeding triggers the molting process and, after five nymphal instar stages, the insect reaches the winged adult form. After the final ecdysis, the young adult still has a lot of blood in the midgut and, thus, we have investigated the changes in protein and lipid contents that are observed in the insect organs as digestion continues after molting. Total midgut protein content decreased during the days after the ecdysis, and digestion was finished fifteen days later. Simultaneously, proteins and triacylglycerols present in the fat body were mobilized, and their contents decreased, whereas they increased in both the ovary and the flight muscle. In order to evaluate the activity of de novo lipogenesis of each organ, the fat body, ovary and flight muscle were incubated in the presence of radiolabeled acetate, and the fat body showed the highest efficiency rate (around 47%) to convert the taken up acetate into lipids. The levels of de novo lipid synthesis in the flight muscle and ovary were very low. When 3H-palmitate was injected into the young females, its incorporation by the flight muscle was higher than by the ovary or the fat body. In the flight muscle, the 3H-palmitate was similarly distributed amongst triacylglycerols, phospholipids, diacylglycerols and free fatty acids, while in the ovary and fat body it was mostly found in triacylglycerols and phospholipids. The flight muscle was not fully developed after the molt, and at day two no lipid droplets were observed. At day five, very small lipid droplets were present, and they increased in size up to day fifteen. The diameter of the muscle fibers also increased from day two to fifteen, as well as the internuclear distance, indicating that muscle hypertrophy occurred along these days. The lipid droplets from the fat body showed a different pattern, and their diameter decreased after day two, but started to increase again at day ten. The data presented herein describes the development of the flight muscle after the final ecdysis, and modifications that occur regarding lipid stores. We show that, after molting, substrates that are present in the midgut and fat body are mobilized and directed to the ovary and flight muscle, for the adults of R. prolixus to be ready to feed and reproduce.
Collapse
Affiliation(s)
- Valdir Braz
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lukas Selim
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Geyse Gomes
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, UFRJ Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Manoel Luis Costa
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, UFRJ Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Claudia Mermelstein
- Laboratório de Diferenciação Muscular, Instituto de Ciências Biomédicas, UFRJ Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Katia C Gondim
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| |
Collapse
|
7
|
Fernandez-Acosta M, Romero JI, Bernabó G, Velázquez-Campos GM, Gonzalez N, Mares ML, Werbajh S, Avendaño-Vázquez LA, Rechberger GN, Kühnlein RP, Marino-Buslje C, Cantera R, Rezaval C, Ceriani MF. orsai, the Drosophila homolog of human ETFRF1, links lipid catabolism to growth control. BMC Biol 2022; 20:233. [PMID: 36266680 PMCID: PMC9585818 DOI: 10.1186/s12915-022-01417-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 09/26/2022] [Indexed: 11/24/2022] Open
Abstract
Background Lipid homeostasis is an evolutionarily conserved process that is crucial for energy production, storage and consumption. Drosophila larvae feed continuously to achieve the roughly 200-fold increase in size and accumulate sufficient reserves to provide all energy and nutrients necessary for the development of the adult fly. The mechanisms controlling this metabolic program are poorly understood. Results Herein we identified a highly conserved gene, orsai (osi), as a key player in lipid metabolism in Drosophila. Lack of osi function in the larval fat body, the regulatory hub of lipid homeostasis, reduces lipid reserves and energy output, evidenced by decreased ATP production and increased ROS levels. Metabolic defects due to reduced Orsai (Osi) in time trigger defective food-seeking behavior and lethality. Further, we demonstrate that downregulation of Lipase 3, a fat body-specific lipase involved in lipid catabolism in response to starvation, rescues the reduced lipid droplet size associated with defective orsai. Finally, we show that osi-related phenotypes are rescued through the expression of its human ortholog ETFRF1/LYRm5, known to modulate the entry of β-oxidation products into the electron transport chain; moreover, knocking down electron transport flavoproteins EtfQ0 and walrus/ETFA rescues osi-related phenotypes, further supporting this mode of action. Conclusions These findings suggest that Osi may act in concert with the ETF complex to coordinate lipid homeostasis in the fat body in response to stage-specific demands, supporting cellular functions that in turn result in an adaptive behavioral response. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01417-w.
Collapse
Affiliation(s)
- Magdalena Fernandez-Acosta
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Juan I Romero
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Guillermo Bernabó
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina.,Present Address: Innovid, Buenos Aires, Argentina
| | - Giovanna M Velázquez-Campos
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Nerina Gonzalez
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - M Lucía Mares
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Santiago Werbajh
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina.,Present Address: Fundación Cassará, Buenos Aires, Argentina
| | - L Amaranta Avendaño-Vázquez
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina.,Present Address: IFIBYNE-CONICET, Buenos Aires, Argentina
| | - Gerald N Rechberger
- Institute for Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Ronald P Kühnlein
- Institute for Molecular Biosciences, University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria.,Field of Excellence BioHealth - University of Graz, Graz, Austria
| | - Cristina Marino-Buslje
- Laboratorio de Bioinformática Estructural, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina
| | - Rafael Cantera
- Departamento de Biología del Neurodesarrollo, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.,Zoology Department, Stockholm University, Stockholm, Sweden
| | - Carolina Rezaval
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina.,Present Address: School of Biosciences, University of Birmingham, Birmingham, UK
| | - M Fernanda Ceriani
- Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir - Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA- CONICET), Buenos Aires, Argentina.
| |
Collapse
|
8
|
Liu B, Pang L, Ji Y, Fang L, Tian CW, Chen J, Chen C, Zhong Y, Ou WC, Xiong Y, Liu SM. MEF2A Is the Trigger of Resveratrol Exerting Protection on Vascular Endothelial Cell. Front Cardiovasc Med 2022; 8:775392. [PMID: 35047575 PMCID: PMC8762055 DOI: 10.3389/fcvm.2021.775392] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/09/2021] [Indexed: 12/29/2022] Open
Abstract
Both resveratrol and myocyte enhancer factor 2A (MEF2A) may protect vascular endothelial cell (VEC) through activating the expression of SIRT1. However, the relationship between resveratrol and MEF2A is unclear. We aimed to investigate the deeper mechanism of resveratrol in protecting vascular endothelial cells and whether MEF2A plays a key role in the protective function of resveratrol. Human umbilical vein endothelial cell (HUVEC) was used for in vitro study, and small interfere RNA was used for silencing MEF2A. Silencing MEF2A in the vascular endothelium (VE) of ApoE−/− mice was performed by tail injection with adeno associated virus expressing si-mef2a-shRNA. The results showed that treatment of HUVEC with resveratrol significantly up-regulated MEF2A, and prevented H2O2-induced but not siRNA-induced down-regulation of MEF2A. Under various experimental conditions, the expression of SIRT1 changed with the level of MEF2A. Resveratrol could rescue from cell apoptosis, reduction of cell proliferation and viability induced by H2O2, but could not prevent against that caused by silencing MEF2A with siRNA. Silencing MEF2A in VE of apoE−/− mice decreased the expression of SIRT1, increased the plasma LDL-c, and abrogated the function of resveratrol on reducing triglyceride. Impaired integrity of VE and aggravated atherosclerotic lesion were observed in MEF2A silenced mice through immunofluorescence and oil red O staining, respectively. In conclusion, resveratrol enhances MEF2A expression, and the upregulation of MEF2A is required for the endothelial protective benefits of resveratrol in vitro via activating SIRT1. Our work has also explored the in vivo relevance of this signaling pathway in experimental models of atherosclerosis and lipid dysregulation, setting the stage for more comprehensive phenotyping in vivo and further defining the molecular mechanisms.
Collapse
Affiliation(s)
- Benrong Liu
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Lihua Pang
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yang Ji
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Lei Fang
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Chao Wei Tian
- Department of Emergency, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.,Department of General Practice, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Jing Chen
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Changnong Chen
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yun Zhong
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Wen-Chao Ou
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yujuan Xiong
- Department of Laboratory Medicine, Panyu Hospital of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shi Ming Liu
- Guangdong Key Laboratory of Vascular Diseases, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Cardiovascular Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| |
Collapse
|
9
|
Heier C, Klishch S, Stilbytska O, Semaniuk U, Lushchak O. The Drosophila model to interrogate triacylglycerol biology. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158924. [PMID: 33716135 DOI: 10.1016/j.bbalip.2021.158924] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 02/24/2021] [Accepted: 03/05/2021] [Indexed: 12/21/2022]
Abstract
The deposition of storage fat in the form of triacylglycerol (TAG) is an evolutionarily conserved strategy to cope with fluctuations in energy availability and metabolic stress. Organismal TAG storage in specialized adipose tissues provides animals a metabolic reserve that sustains survival during development and starvation. On the other hand, excessive accumulation of adipose TAG, defined as obesity, is associated with an increasing prevalence of human metabolic diseases. During the past decade, the fruit fly Drosophila melanogaster, traditionally used in genetics and developmental biology, has been established as a versatile model system to study TAG metabolism and the etiology of lipid-associated metabolic diseases. Similar to humans, Drosophila TAG homeostasis relies on the interplay of organ systems specialized in lipid uptake, synthesis, and processing, which are integrated by an endocrine network of hormones and messenger molecules. Enzymatic formation of TAG from sugar or dietary lipid, its storage in lipid droplets, and its mobilization by lipolysis occur via mechanisms largely conserved between Drosophila and humans. Notably, dysfunctional Drosophila TAG homeostasis occurs in the context of aging, overnutrition, or defective gene function, and entails tissue-specific and organismal pathologies that resemble human disease. In this review, we summarize the physiology and biochemistry of TAG in Drosophila and outline the potential of this organism as a model system to understand the genetic and dietary basis of TAG storage and TAG-related metabolic disorders.
Collapse
Affiliation(s)
- Christoph Heier
- Institute of Molecular Biosciences, University of Graz, NAWI Graz, Humboldtstrasse 50, A-8010 Graz, Austria; BioTechMed-Graz, Graz, Austria.
| | - Svitlana Klishch
- Department of Biochemistry and Biotechnology, Department Biochemistry 1, Faculty of Natural Sciences, Vasyl Stefanyk Precarpathian National University, 57 Shevchenka str, Ivano-Frankivsk 76018, Ukraine
| | - Olha Stilbytska
- Department of Biochemistry and Biotechnology, Department Biochemistry 1, Faculty of Natural Sciences, Vasyl Stefanyk Precarpathian National University, 57 Shevchenka str, Ivano-Frankivsk 76018, Ukraine
| | - Uliana Semaniuk
- Department of Biochemistry and Biotechnology, Department Biochemistry 1, Faculty of Natural Sciences, Vasyl Stefanyk Precarpathian National University, 57 Shevchenka str, Ivano-Frankivsk 76018, Ukraine
| | - Oleh Lushchak
- Department of Biochemistry and Biotechnology, Department Biochemistry 1, Faculty of Natural Sciences, Vasyl Stefanyk Precarpathian National University, 57 Shevchenka str, Ivano-Frankivsk 76018, Ukraine.
| |
Collapse
|
10
|
Krautz R, Khalili D, Theopold U. Tissue-autonomous immune response regulates stress signaling during hypertrophy. eLife 2020; 9:64919. [PMID: 33377870 PMCID: PMC7880693 DOI: 10.7554/elife.64919] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 12/29/2020] [Indexed: 12/19/2022] Open
Abstract
Postmitotic tissues are incapable of replacing damaged cells through proliferation, but need to rely on buffering mechanisms to prevent tissue disintegration. By constitutively activating the Ras/MAPK-pathway via RasV12-overexpression in the postmitotic salivary glands (SGs) of Drosophila larvae, we overrode the glands adaptability to growth signals and induced hypertrophy. The accompanied loss of tissue integrity, recognition by cellular immunity, and cell death are all buffered by blocking stress signaling through a genuine tissue-autonomous immune response. This novel, spatio-temporally tightly regulated mechanism relies on the inhibition of a feedback-loop in the JNK-pathway by the immune effector and antimicrobial peptide Drosomycin. While this interaction might allow growing SGs to cope with temporary stress, continuous Drosomycin expression in RasV12-glands favors unrestricted hypertrophy. These findings indicate the necessity to refine therapeutic approaches that stimulate immune responses by acknowledging their possible, detrimental effects in damaged or stressed tissues. Tissues and organs work hard to maintain balance in everything from taking up nutrients to controlling their growth. Ageing, wounding, sickness, and changes in the genetic code can all alter this balance, and cause the tissue or organ to lose some of its cells. Many tissues restore this loss by dividing their remaining cells to fill in the gaps. But some – like the salivary glands of fruit fly larvae – have lost this ability. Tissues like these rely on being able to sense and counteract problems as they arise so as to not lose their balance in the first place. The immune system and stress responses are crucial for this process. They trigger steps to correct the problem and interact with each other to find a common decision about the fate of the affected tissue. To better understand how the immune system and stress response work together, Krautz, Khalili and Theopold genetically manipulated cells in the salivary gland of fruit fly larvae. These modifications switched on signals that stimulate cells to keep growing, causing the salivary gland’s tissue to slowly lose its balance and trigger the stress and immune response. The experiments showed that while the stress response instructed the cells in the gland to die, a peptide released by the immune system called Drosomycin blocked this response and prevented the tissue from collapsing. The cells in the part of the gland not producing this immune peptide were consequently killed by the stress response. When all the cells in the salivary gland were forced to produce Drosomycin, none of the cells died and the whole tissue survived. But it also allowed the cells in the gland to grow uncontrollably, like a tumor, threatening the health of the entire organism. Mapping the interactions between immune and stress pathways could help to fine-tune treatments that can prevent tissue damage. Fruit flies share many genetic features and molecular pathways with humans. So, the next step towards these kinds of treatments would be to screen for similar mechanisms that block stress activation in damaged human tissues. But this research carries a warning: careless activation of the immune system to protect stressed tissues could lead to uncontrolled tissue growth, and might cause more harm than good.
Collapse
Affiliation(s)
- Robert Krautz
- Department of Molecular Biosciences, The Wenner-Gren Institute (MBW), Stockholm University, Stockholm, Sweden
| | - Dilan Khalili
- Department of Molecular Biosciences, The Wenner-Gren Institute (MBW), Stockholm University, Stockholm, Sweden
| | - Ulrich Theopold
- Department of Molecular Biosciences, The Wenner-Gren Institute (MBW), Stockholm University, Stockholm, Sweden
| |
Collapse
|
11
|
Zhao X, Li X, Shi X, Karpac J. Diet-MEF2 interactions shape lipid droplet diversification in muscle to influence Drosophila lifespan. Aging Cell 2020; 19:e13172. [PMID: 32537848 PMCID: PMC7433001 DOI: 10.1111/acel.13172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 04/05/2020] [Accepted: 05/05/2020] [Indexed: 12/12/2022] Open
Abstract
The number, size, and composition of lipid droplets can be influenced by dietary changes that shift energy substrate availability. This diversification of lipid droplets can promote metabolic flexibility and shape cellular stress responses in unique tissues with distinctive metabolic roles. Using Drosophila, we uncovered a role for myocyte enhancer factor 2 (MEF2) in modulating diet-dependent lipid droplet diversification within adult striated muscle, impacting mortality rates. Muscle-specific attenuation of MEF2, whose chronic activation maintains glucose and mitochondrial homeostasis, leads to the accumulation of large, cholesterol ester-enriched intramuscular lipid droplets in response to high calorie, carbohydrate-sufficient diets. The diet-dependent accumulation of these lipid droplets also correlates with both enhanced stress protection in muscle and increases in organismal lifespan. Furthermore, MEF2 attenuation releases an antagonistic regulation of cell cycle gene expression programs, and up-regulation of Cyclin E is required for diet- and MEF2-dependent diversification of intramuscular lipid droplets. The integration of MEF2-regulated gene expression networks with dietary responses thus plays a critical role in shaping muscle metabolism and function, further influencing organismal lifespan. Together, these results highlight a potential protective role for intramuscular lipid droplets during dietary adaptation.
Collapse
Affiliation(s)
- Xiao Zhao
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| | - Xiaotong Li
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| | - Xiangyu Shi
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| | - Jason Karpac
- Department of Molecular and Cellular MedicineTexas A&M University Health Science CenterBryanTXUSA
| |
Collapse
|