1
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Bai X, Smith HE, Golden A. Identification of genetic suppressors for a BSCL2 lipodystrophy pathogenic variant in Caenorhabditis elegans. Dis Model Mech 2024; 17:dmm050524. [PMID: 38454882 PMCID: PMC11051982 DOI: 10.1242/dmm.050524] [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: 09/22/2023] [Accepted: 03/04/2024] [Indexed: 03/09/2024] Open
Abstract
Seipin (BSCL2), a conserved endoplasmic reticulum protein, plays a critical role in lipid droplet (LD) biogenesis and in regulating LD morphology, pathogenic variants of which are associated with Berardinelli-Seip congenital generalized lipodystrophy type 2 (BSCL2). To model BSCL2 disease, we generated an orthologous BSCL2 variant, seip-1(A185P), in Caenorhabditis elegans. In this study, we conducted an unbiased chemical mutagenesis screen to identify genetic suppressors that restore embryonic viability in the seip-1(A185P) mutant background. A total of five suppressor lines were isolated and recovered from the screen. The defective phenotypes of seip-1(A185P), including embryonic lethality and impaired eggshell formation, were significantly suppressed in each suppressor line. Two of the five suppressor lines also alleviated the enlarged LDs in the oocytes. We then mapped a suppressor candidate gene, lmbr-1, which is an ortholog of human limb development membrane protein 1 (LMBR1). The CRISPR/Cas9 edited lmbr-1 suppressor alleles, lmbr-1(S647F) and lmbr-1(P314L), both significantly suppressed embryonic lethality and defective eggshell formation in the seip-1(A185P) background. The newly identified suppressor lines offer valuable insights into potential genetic interactors and pathways that may regulate seipin in the lipodystrophy model.
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Affiliation(s)
- Xiaofei Bai
- Department of Biology, University of Florida, Gainesville, FL 32610, USA
- Genetics Institute, University of Florida, Gainesville, FL 32610, USA
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Harold E. Smith
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andy Golden
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Wang S, Zhang M, Sun H, Li T, Hao J, Fang M, Dong J, Xu H. Multi-omics analysis of TLCD1 as a promising biomarker in pan-cancer. Front Cell Dev Biol 2024; 11:1305906. [PMID: 38559424 PMCID: PMC10978584 DOI: 10.3389/fcell.2023.1305906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 12/31/2023] [Indexed: 04/04/2024] Open
Abstract
Background: The TLC Domain Containing 1 (TLCD1) protein, a key regulator of phosphatidylethanolamine (PE) composition, is distributed across several cellular membranes, including mitochondrial plasma membranes. Existing research has revealed the impact of TLCD1 on the development of non-alcoholic fatty liver disease. However, there remains a gap in comprehensive pan-cancer analyses of TLCD1, and the precise role of TLCD1 in cancer patient prognosis and immunological responses remains elusive. This study aims to provide a comprehensive visualization of the prognostic landscape associated with TLCD1 across a spectrum of cancers, while shedding light on the potential links between TLCD1 expression within the tumor microenvironment and immune infiltration characteristics. Methods: TLCD1 expression data were obtained from GTEx, TCGA, and HPA data repositories. Multiple databases including TIMER, HPA, TISIDB, cBioPortal, GEPIA2, STRING, KEGG, GO, and CancerSEA were used to investigate the expression pattern, diagnostic and prognostic significance, mutation status, functional analysis, and functional status of TLCD1. In addition, we evaluated the relationship between TLCD1 expression and immune infiltration, tumor mutational burden (TMB), microsatellite instability (MSI), and immune-related genes in pan-cancer. Furthermore, the association of TLCD1 with drug sensitivity was analyzed using the CellMiner database. Results: We found that TLCD1 is generally highly expressed in pan-cancers and is significantly associated with the staging and prognosis of various cancers. Furthermore, our results also showed that TLCD1 was significantly associated with immune cell infiltration and immune regulatory factor expression. Using CellMiner database analysis, we then found a strong correlation between TLCD1 expression and sensitivity to anticancer drugs, indicating its potential as a therapeutic target. The most exciting finding is that high TLCD1 expression is associated with worse survival and prognosis in GBM and SKCM patients receiving anti-PD1 therapy. These findings highlight the potential of TLCD1 as a predictive biomarker for response to immunotherapy. Conclusion: TLCD1 plays a role in the regulation of immune infiltration and affects the prognosis of patients with various cancers. It serves as both a prognostic and immunologic biomarker in human cancer.
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Affiliation(s)
- Shengli Wang
- Zhuhai Institute of Translational Medicine, Zhuhai People’s Hospital Affiliated With Jinan University, Jinan University, Zhuhai, Guangdong, China
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Mingyue Zhang
- Zhuhai Institute of Translational Medicine, Zhuhai People’s Hospital Affiliated With Jinan University, Jinan University, Zhuhai, Guangdong, China
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Hongyan Sun
- Zhuhai Institute of Translational Medicine, Zhuhai People’s Hospital Affiliated With Jinan University, Jinan University, Zhuhai, Guangdong, China
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Tao Li
- Zhuhai Institute of Translational Medicine, Zhuhai People’s Hospital Affiliated With Jinan University, Jinan University, Zhuhai, Guangdong, China
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Jianlei Hao
- Zhuhai Institute of Translational Medicine, Zhuhai People’s Hospital Affiliated With Jinan University, Jinan University, Zhuhai, Guangdong, China
- The Biomedical Translational Research Institute, Faculty of Medical Science, Jinan University, Guangzhou, Guangdong, China
| | - Meixia Fang
- Department of Laboratory Animal, Institute of Laboratory Animal Science, Jinan University, Guangzhou, Guangdong, China
| | - Jie Dong
- Department of Clinical Laboratory, Guangzhou Twelfth People’s Hospital, Guangzhou, Guangdong, China
| | - Hongbiao Xu
- Department of Thyroid and Breast Surgery, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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3
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Banerjee S, Daetwyler S, Bai X, Michaud M, Jouhet J, Madhugiri S, Johnson E, Wang CW, Fiolka R, Toulmay A, Prinz WA. The Vps13-like protein BLTP2 is pro-survival and regulates phosphatidylethanolamine levels in the plasma membrane to maintain its fluidity and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.04.578804. [PMID: 38370643 PMCID: PMC10871178 DOI: 10.1101/2024.02.04.578804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Lipid transport proteins (LTPs) facilitate nonvesicular lipid exchange between cellular compartments and have critical roles in lipid homeostasis1. A new family of bridge-like LTPs (BLTPs) is thought to form lipid-transporting conduits between organelles2. One, BLTP2, is conserved across species but its function is not known. Here, we show that BLTP2 and its homolog directly regulate plasma membrane (PM) fluidity by increasing the phosphatidylethanolamine (PE) level in the PM. BLTP2 localizes to endoplasmic reticulum (ER)-PM contact sites34, 5, suggesting it transports PE from the ER to the PM. We find BLTP2 works in parallel with another pathway that regulates intracellular PE distribution and PM fluidity6, 7. BLTP2 expression correlates with breast cancer aggressiveness8-10. We found BLTP2 facilitates growth of a human cancer cell line and sustains its aggressiveness in an in vivo model of metastasis, suggesting maintenance of PM fluidity by BLTP2 may be critical for tumorigenesis in humans.
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Affiliation(s)
- Subhrajit Banerjee
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stephan Daetwyler
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaofei Bai
- Department of Biology, University of Florida, Gainesville, FL, USA
- Genetics Institute, University of Florida, Gainesville, FL, USA
| | - Morgane Michaud
- Université Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, Grenoble, France
| | - Juliette Jouhet
- Université Grenoble Alpes, CNRS, CEA, INRAE, IRIG, LPCV, Grenoble, France
| | - Shruthi Madhugiri
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Emma Johnson
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chao-Wen Wang
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
| | - Reto Fiolka
- Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Alexandre Toulmay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - William A Prinz
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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4
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Dinh BL, Tang E, Taparra K, Nakatsuka N, Chen F, Chiang CWK. Recombination map tailored to Native Hawaiians may improve robustness of genomic scans for positive selection. Hum Genet 2024; 143:85-99. [PMID: 38157018 PMCID: PMC10794367 DOI: 10.1007/s00439-023-02625-2] [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: 09/02/2023] [Accepted: 11/25/2023] [Indexed: 01/03/2024]
Abstract
Recombination events establish the patterns of haplotypic structure in a population and estimates of recombination rates are used in several downstream population and statistical genetic analyses. Using suboptimal maps from distantly related populations may reduce the efficacy of genomic analyses, particularly for underrepresented populations such as the Native Hawaiians. To overcome this challenge, we constructed recombination maps using genome-wide array data from two study samples of Native Hawaiians: one reflecting the current admixed state of Native Hawaiians (NH map) and one based on individuals of enriched Polynesian ancestries (PNS map) with the potential to be used for less admixed Polynesian populations such as the Samoans. We found the recombination landscape to be less correlated with those from other continental populations (e.g. Spearman's rho = 0.79 between PNS and CEU (Utah residents with Northern and Western European ancestry) compared to 0.92 between YRI (Yoruba in Ibadan, Nigeria) and CEU at 50 kb resolution), likely driven by the unique demographic history of the Native Hawaiians. PNS also shared the fewest recombination hotspots with other populations (e.g. 8% of hotspots shared between PNS and CEU compared to 27% of hotspots shared between YRI and CEU). We found that downstream analyses in the Native Hawaiian population, such as local ancestry inference, imputation, and IBD segment and relatedness detections, would achieve similar efficacy when using the NH map compared to an omnibus map. However, for genome scans of adaptive loci using integrated haplotype scores, we found several loci with apparent genome-wide significant signals (|Z-score|> 4) in Native Hawaiians that would not have been significant when analyzed using NH-specific maps. Population-specific recombination maps may therefore improve the robustness of haplotype-based statistics and help us better characterize the evolutionary history that may underlie Native Hawaiian-specific health conditions that persist today.
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Affiliation(s)
- Bryan L Dinh
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Echo Tang
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA
| | - Kekoa Taparra
- Department of Radiation Oncology, Stanford University, Palo Alto, CA, USA
| | | | - Fei Chen
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Charleston W K Chiang
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, USA.
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
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5
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Fanelli MJ, Welsh CM, Lui DS, Smulan LJ, Walker AK. Immunity-linked genes are stimulated by a membrane stress pathway linked to Golgi function and the ARF-1 GTPase. SCIENCE ADVANCES 2023; 9:eadi5545. [PMID: 38055815 PMCID: PMC10699786 DOI: 10.1126/sciadv.adi5545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
Infection response and other immunity-linked genes (ILGs) were first named in Caenorhabditis elegans-based expression after pathogen challenge, but many are also up-regulated when lipid metabolism is perturbed. Why pathogen attack and metabolic changes both increase ILGs is unclear. We find that ILGs are activated when phosphatidylcholine (PC) levels change in membranes of secretory organelles in C. elegans. RNAi targeting of the ADP-ribosylation factor arf-1, which disrupts the Golgi and secretory function, also activates ILGs. Low PC limits ARF-1 function, suggesting a mechanism for ILG activation via lipid metabolism, as part of a membrane stress response acting outside the ER. RNAi of selected ILGs uncovered defects in the secretion of two GFP reporters and the accumulation of a pathogen-responsive complement C1r/C1s, Uegf, Bmp1 (CUB) domain fusion protein. Our data argue that up-regulation of some ILGs is a coordinated response to changes in trafficking and may act to counteract stress on secretory function.
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Affiliation(s)
- Matthew J. Fanelli
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
| | - Christofer M. Welsh
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
- Morningside School of Biomedical Sciences, UMASS Chan Medical School, Worcester, MA, USA
| | - Dominique S. Lui
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
| | - Lorissa J. Smulan
- Department of Medicine, UMASS Chan Medical School, Worcester, MA, USA
| | - Amy K. Walker
- Program in Molecular Medicine, UMASS Chan Medical School, Worcester, MA, USA
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6
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Gawden-Bone CM, Lehner PJ, Volkmar N. As a matter of fat: Emerging roles of lipid-sensitive E3 ubiquitin ligases. Bioessays 2023; 45:e2300139. [PMID: 37890275 DOI: 10.1002/bies.202300139] [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: 07/28/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023]
Abstract
The dynamic structure and composition of lipid membranes need to be tightly regulated to control the vast array of cellular processes from cell and organelle morphology to protein-protein interactions and signal transduction pathways. To maintain membrane integrity, sense-and-response systems monitor and adjust membrane lipid composition to the ever-changing cellular environment, but only a relatively small number of control systems have been described. Here, we explore the emerging role of the ubiquitin-proteasome system in monitoring and maintaining membrane lipid composition. We focus on the ER-resident RNF145 E3 ubiquitin ligase, its role in regulating adiponectin receptor 2 (ADIPOR2), its lipid hydrolase substrate, and the broader implications for understanding the homeostatic processes that fine-tune cellular membrane composition.
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Affiliation(s)
- Christian M Gawden-Bone
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, UK
| | - Paul J Lehner
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, UK
| | - Norbert Volkmar
- Institute for Molecular Systems Biology (IMSB), ETH Zürich, Zürich, Switzerland
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7
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Kumar A, Daschakraborty S. Anomalous lateral diffusion of lipids during the fluid/gel phase transition of a lipid membrane. Phys Chem Chem Phys 2023; 25:31431-31443. [PMID: 37962400 DOI: 10.1039/d3cp04081j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
A lipid membrane undergoes a phase transition from fluid to gel phase upon changing external thermodynamic conditions, such as decreasing temperature and increasing pressure. Extremophilic organisms face the challenge of preventing this deleterious phase transition. The main focus of their adaptive strategy is to facilitate effective temperature sensing through sensor proteins, relying on the drastic changes in packing density and membrane fluidity during the phase transition. Although the changes in packing density parameters due to the fluid/gel phase transition are studied in detail, the impact on membrane fluidity is less explored in the literature. Understanding the lateral diffusive dynamics of lipids in response to temperature, particularly during the fluid/gel phase transition, is albeit crucial. Here we have simulated the phase transition of a single component lipid membrane composed of dipalmitoylphosphatidylcholine (DPPC) lipids using a coarse-grained (CG) model and studied the changes of the structural and dynamical properties. It is observed that near the phase transition point, both fluid and gel phase domains coexist together. The dynamics remains highly non-Gaussian for a long time even when the mean square displacement reaches the Fickian regime at a much earlier time. This Fickian yet non-Gaussian diffusion (FnGD) is a characteristic of a highly heterogeneous system, previously observed for the lateral diffusion of lipids in raft mimetic membranes having liquid-ordered and liquid-disordered phases co-existing together. We have analyzed the molecular trajectories and calculated the jump-diffusion of the lipids, stemming from sudden jump translations, using a translational jump-diffusion (TJD) approach. An overwhelming contribution of the jump-diffusion of the lipids is observed suggesting anomalous diffusion of lipids during fluid/gel phase transition of the membrane. These results are important in unravelling the intricate nature of lipid diffusion during the phase transition of the membrane and open up a new possibility of investigating the most significant change of membrane properties during phase transition, which can be effectively sensed by proteins.
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Affiliation(s)
- Abhay Kumar
- Department of Chemistry, Indian Institute of Technology Patna, Bihar 801106, India.
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8
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Bai X, Smith HE, Golden A. Identification of Genetic Suppressors for a Berardinelli-Seip Congenital Generalized Lipodystrophy Type 2 (BSCL2) Pathogenic Variant in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.559059. [PMID: 37790539 PMCID: PMC10542546 DOI: 10.1101/2023.09.22.559059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Maintaining the metabolic homeostasis of fatty acids is crucial for human health. Excess fatty acids are stored in lipid droplets (LDs), the primary energy reservoir that helps regulate fat and lipid homeostasis in nearly all cell types. Seipin (BSCL2), a conserved endoplasmic reticulum protein, plays a critical role in LD biogenesis and regulating LD morphology. Pathogenic variants of seipin are associated with multiple human genetic diseases, including Berardinelli-Seip Congenital Generalized Lipodystrophy Type 2 (BSCL2). However, the cellular and molecular mechanisms by which dysfunctional seipin leads to these diseases remain unclear. To model BSCL2 disease, we generated an orthologous BSCL2 pathogenic variant seip-1(A185P) using CRISPR/Cas9 genome editing in Caenorhabditis elegans . This variant led to severe developmental and cellular defects, including embryonic lethality, impaired eggshell formation, and abnormally enlarged LDs. We set out to identify genetic determinants that could suppress these defective phenotypes in the seip-1(A185P) mutant background. To this end, we conducted an unbiased chemical mutagenesis screen to identify genetic suppressors that restore embryonic viability in the seip-1(A185P) mutant background. A total of five suppressor lines were isolated and recovered from the screen. The defective phenotypes of seip-1(A185P) , including embryonic lethality and impaired eggshell formation, were significantly suppressed in each suppressor line. Two of the five suppressor lines also alleviated the enlarged LDs in the oocytes. We then mapped a suppressor candidate gene, R05D3.2 (renamed as lmbr-1 ), which is an ortholog of human LMBR1 (limb development membrane protein 1). The CRISPR/Cas9 edited lmbr-1 suppressor alleles, lmbr-1(Ser647Phe) and lmbr-1(Pro314Leu) , both significantly suppressed embryonic lethality and defective eggshell formation in the seip-1(A185P) background. The newly identified suppressor lines offer valuable insights into potential genetic interactors and pathways that may regulate seipin in the lipodystrophy model.
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9
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Dinh BL, Tang E, Taparra K, Nakatsuka N, Chen F, Chiang CWK. Recombination map tailored to Native Hawaiians improves robustness of genomic scans for positive selection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548735. [PMID: 37503129 PMCID: PMC10370006 DOI: 10.1101/2023.07.12.548735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Recombination events establish the patterns of haplotypic structure in a population and estimates of recombination rates are used in several downstream population and statistical genetic analyses. Using suboptimal maps from distantly related populations may reduce the efficacy of genomic analyses, particularly for underrepresented populations such as the Native Hawaiians. To overcome this challenge, we constructed recombination maps using genome-wide array data from two study samples of Native Hawaiians: one reflecting the current admixed state of Native Hawaiians (NH map), and one based on individuals of enriched Polynesian ancestries (PNS map) with the potential to be used for less admixed Polynesian populations such as the Samoans. We found the recombination landscape to be less correlated with those from other continental populations (e.g. Spearman's rho = 0.79 between PNS and CEU (Utah residents with Northern and Western European ancestry) compared to 0.92 between YRI (Yoruba in Ibadan, Nigeria) and CEU at 50 kb resolution), likely driven by the unique demographic history of the Native Hawaiians. PNS also shared the fewest recombination hotspots with other populations (e.g. 8% of hotspots shared between PNS and CEU compared to 27% of hotspots shared between YRI and CEU). We found that downstream analyses in the Native Hawaiian population, such as local ancestry inference, imputation, and IBD segment and relatedness detections, would achieve similar efficacy when using the NH map compared to an omnibus map. However, for genome scans of adaptive loci using integrated haplotype scores, we found several loci with apparent genome-wide significant signals (|Z-score| > 4) in Native Hawaiians that would not have been significant when analyzed using NH-specific maps. Population-specific recombination maps may therefore improve the robustness of haplotype-based statistics and help us better characterize the evolutionary history that may underlie Native Hawaiian-specific health conditions that persist today.
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Affiliation(s)
- Bryan L Dinh
- Department of Quantitative and Computational Biology, University of Southern California
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California
| | - Echo Tang
- Department of Quantitative and Computational Biology, University of Southern California
| | - Kekoa Taparra
- Department of Radiation Oncology, Stanford University, Palo Alto, California
| | | | - Fei Chen
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California
| | - Charleston W K Chiang
- Department of Quantitative and Computational Biology, University of Southern California
- Center for Genetic Epidemiology, Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California
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10
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Pilon M, Ruiz M. PAQR proteins and the evolution of a superpower: Eating all kinds of fats: Animals rely on evolutionarily conserved membrane homeostasis proteins to compensate for dietary variation. Bioessays 2023; 45:e2300079. [PMID: 37345585 DOI: 10.1002/bies.202300079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/23/2023]
Abstract
Recently published work showed that members of the PAQR protein family are activated by cell membrane rigidity and contribute to our ability to eat a wide variety of diets. Cell membranes are primarily composed of phospholipids containing dietarily obtained fatty acids, which poses a challenge to membrane properties because diets can vary greatly in their fatty acid composition and could impart opposite properties to the cellular membranes. In particular, saturated fatty acids (SFAs) can pack tightly and form rigid membranes (like butter at room temperature) while unsaturated fatty acids (UFAs) form more fluid membranes (like vegetable oils). Proteins of the PAQR protein family, characterized by the presence of seven transmembrane domains and a cytosolic N-terminus, contribute to membrane homeostasis in bacteria, yeasts, and animals. These proteins respond to membrane rigidity by stimulating fatty acid desaturation and incorporation of UFAs into phospholipids and explain the ability of animals to thrive on diets with widely varied fat composition. Also see the video abstract here: https://youtu.be/6ckcvaDdbQg.
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Affiliation(s)
- Marc Pilon
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Mario Ruiz
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
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11
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Xatse MA, Vieira AFC, Byrne C, Olsen CP. Targeted Lipidomics Reveals a Novel Role for Glucosylceramides in Glucose Response. J Lipid Res 2023:100394. [PMID: 37245562 PMCID: PMC10320606 DOI: 10.1016/j.jlr.2023.100394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 05/19/2023] [Accepted: 05/21/2023] [Indexed: 05/30/2023] Open
Abstract
The addition of excess glucose to the diet drives a coordinated response of lipid metabolism pathways to tune the membrane composition to the altered diet. Here, we have employed targeted lipidomic approaches to quantify the specific changes in the phospholipid and sphingolipid populations that occur in elevated glucose conditions. The lipids within wildtype Caenorhabditis elegans are strikingly stable with no significant changes identified in our global mass spectrometry-based analysis. Previous work has identified ELO-5, an elongase that is critical for the synthesis of monomethyl-branched chain fatty acids (mmBCFAs), as essential for surviving elevated glucose conditions. Therefore, we performed targeted lipidomics on elo-5 RNAi-fed animals and identified several significant changes in these animals in lipid species that contain mmBCFAs as well as in species that do not contain mmBCFAs. Of particular note, we identified a specific glucosylceramide (GlcCer 17:1;O2/22:0;O) that is also significantly upregulated with glucose in wildtype animals. Furthermore, compromising the production of the glucosylceramide pool with elo-3 or cgt-3 RNAi leads to premature death in glucose-fed animals. Taken together, our lipid analysis has expanded the mechanistic understanding of metabolic rewiring with glucose feeding and has identified a new role for the GlcCer 17:1;O2/22:0;O.
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Affiliation(s)
- Mark A Xatse
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Andre F C Vieira
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Chloe Byrne
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA
| | - Carissa Perez Olsen
- From the Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, Massachusetts, USA.
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12
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Ruiz M, Devkota R, Kaper D, Ruhanen H, Busayavalasa K, Radović U, Henricsson M, Käkelä R, Borén J, Pilon M. AdipoR2 recruits protein interactors to promote fatty acid elongation and membrane fluidity. J Biol Chem 2023:104799. [PMID: 37164154 DOI: 10.1016/j.jbc.2023.104799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 04/28/2023] [Accepted: 04/29/2023] [Indexed: 05/12/2023] Open
Abstract
The human AdipoR2 and its C. elegans homolog PAQR-2 are multi-pass plasma membrane proteins that protect cells against membrane rigidification. However, how AdipoR2 promotes membrane fluidity mechanistically is not clear. Using 13C-labelled fatty acids, we show that AdipoR2 can promote the elongation and incorporation of membrane-fluidizing polyunsaturated fatty acids into phospholipids. To elucidate the molecular basis of these activities, we performed immunoprecipitations of tagged AdipoR2 and PAQR-2 expressed in HEK293 cells or whole C. elegans, respectively, and identified co-immunoprecipitated proteins using mass spectroscopy. We found that several of the evolutionarily conserved AdipoR2/PAQR-2 interactors are important for fatty acid elongation and incorporation into phospholipids. We experimentally verified some of these interactions, namely with the dehydratase HACD3 that is essential for the third of four steps in long-chain fatty acid elongation, and ACSL4 that is important for activation of unsaturated fatty acids and their channeling into phospholipids. We conclude that AdipoR2 and PAQR-2 can recruit protein interactors to promote the production and incorporation of unsaturated fatty acids into phospholipids.
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Affiliation(s)
- Mario Ruiz
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Ranjan Devkota
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Delaney Kaper
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Hanna Ruhanen
- Helsinki University Lipidomics Unit, Helsinki Institute of Life Science, Biocenter Finland, Helsinki, Finland; Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Kiran Busayavalasa
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Uroš Radović
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Marcus Henricsson
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Reijo Käkelä
- Helsinki University Lipidomics Unit, Helsinki Institute of Life Science, Biocenter Finland, Helsinki, Finland; Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Jan Borén
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marc Pilon
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
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13
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Nematicidal lipopeptides from Bacillus paralicheniformis and Bacillus subtilis: A comparative study. Appl Microbiol Biotechnol 2023; 107:1537-1549. [PMID: 36719435 DOI: 10.1007/s00253-023-12391-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 12/26/2022] [Accepted: 01/15/2023] [Indexed: 02/01/2023]
Abstract
The aim of this work was to develop a comparative study between Bacillus paralicheniformis TB197 and B. subtilis ATCC 21332 strains in terms of growth, cyclic lipopeptide production, nematicidal activity, and active lipopeptide characteristics. Crude lipopeptide extracts (CLEs) from their fermentation broths were obtained, and their nematicidal activity (NA) was estimated as the mean lethal dose (LD50), employing Caenorhabditis elegans. Using a bioguided approach, CLE components were fractionated by semipreparative thin layer chromatography, and active lipopeptides were characterized by mass spectrometry. Both strains produced similar concentrations of CLEs (p ≥ 0.05) (0.99 ± 0.11 and 1.14 ± 0.15 mg/mL by TB197 and ATCC 21332, respectively). The estimated LD50 values of CLEs from the TB197 and ATCC 21332 strains were 3.88 and 8.15 mg/mL, respectively, showing that the NA of the TB197 strain CLE was 2.1-fold higher (p ≤ 0.05). Mass spectrometry revealed that strain TB197 synthesizes several families of lipopeptides, namely, fengycin A (C14-C17), fengycin B (C16-C17), surfactin (C15-C17), and lichenysin (C12, C13, C14, and C16), from which fengycins and lichenysins possess the highest NA (100 and 60% mortality in C. elegans larvae, respectively), while the ATCC 21332 strain produces mainly surfactin (C13-C17) (NA 63% mortality). The main differences found in this study were that the TB197 strain has a higher tolerance to inhibition by the product, and the lipopeptides they synthesize have a higher nematicidal activity due to the diversity of families compared to ATCC 21332. Likewise, it was shown that more polar lipopeptides (fengycins) are more effective at causing mortality in C. elegans larvae. KEY POINTS: • The nematicidal activity of lipopeptides from TB197 is higher than from ATCC 21332 • TB197 produces surfactin, lichenysin, and fengycin, while ATCC 21332 mainly produces surfactin • The most polar lipopeptides (fengycins) cause more mortality in C. elegans L2.
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14
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Regulation of membrane protein structure and function by their lipid nano-environment. Nat Rev Mol Cell Biol 2023; 24:107-122. [PMID: 36056103 PMCID: PMC9892264 DOI: 10.1038/s41580-022-00524-4] [Citation(s) in RCA: 113] [Impact Index Per Article: 113.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 02/04/2023]
Abstract
Transmembrane proteins comprise ~30% of the mammalian proteome, mediating metabolism, signalling, transport and many other functions required for cellular life. The microenvironment of integral membrane proteins (IMPs) is intrinsically different from that of cytoplasmic proteins, with IMPs solvated by a compositionally and biophysically complex lipid matrix. These solvating lipids affect protein structure and function in a variety of ways, from stereospecific, high-affinity protein-lipid interactions to modulation by bulk membrane properties. Specific examples of functional modulation of IMPs by their solvating membranes have been reported for various transporters, channels and signal receptors; however, generalizable mechanistic principles governing IMP regulation by lipid environments are neither widely appreciated nor completely understood. Here, we review recent insights into the inter-relationships between complex lipidomes of mammalian membranes, the membrane physicochemical properties resulting from such lipid collectives, and the regulation of IMPs by either or both. The recent proliferation of high-resolution methods to study such lipid-protein interactions has led to generalizable insights, which we synthesize into a general framework termed the 'functional paralipidome' to understand the mutual regulation between membrane proteins and their surrounding lipid microenvironments.
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15
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Yoon DS, Byeon E, Kim DH, Lee MC, Shin KH, Hagiwara A, Park HG, Lee JS. Effects of temperature and combinational exposures on lipid metabolism in aquatic invertebrates. Comp Biochem Physiol C Toxicol Pharmacol 2022; 262:109449. [PMID: 36055628 DOI: 10.1016/j.cbpc.2022.109449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/22/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022]
Abstract
Studies of changes in fatty acids in response to environmental temperature changes have been conducted in many species, particularly mammals. However, few studies have considered aquatic invertebrates, even though they are particularly vulnerable to changes in environmental temperature. In this review, we summarize the process by which animals synthesize common fatty acids and point out differences between the fatty acid profiles of vertebrates and those of aquatic invertebrates. Unlike vertebrates, some aquatic invertebrates can directly synthesize polyunsaturated fatty acids (PUFAs), which can be used to respond to temperature changes. Various studies have shown that aquatic invertebrates increase the degree of saturation in their fatty acids through an increase in saturated fatty acid production or a decrease in PUFAs as the temperature increases. In addition, we summarize recent studies that have examined the complex effects of temperature and combinational stressors to determine whether the degree of saturation in aquatic invertebrates is influenced by other factors. The combined effects of carbon dioxide partial pressure, food quality, starvation, salinity, and chemical exposures have been confirmed, and fatty acid profile changes in response to high temperature were greater than those from combinational stressors.
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Affiliation(s)
- Deok-Seo Yoon
- Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Eunjin Byeon
- Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Duck-Hyun Kim
- Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea
| | - Min-Chul Lee
- Department of Food & Nutrition, College of Bio-Nano Technology, Gachon University, Seongnam 13120, South Korea
| | - Kyung-Hoon Shin
- Department of Marine Science and Convergence Engineering, Hanyang University, Ansan 15588, South Korea
| | - Atsushi Hagiwara
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Heum Gi Park
- Department of Marine Ecology and Environment, College of Life Sciences, Gangneung-Wonju National University, Gangneung 25457, South Korea.
| | - Jae-Seong Lee
- Department of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, South Korea.
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16
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Gong J, Chen J, Gu P, Shang Y, Ruppell KT, Yang Y, Wang F, Wen Q, Xiang Y. Shear stress activates nociceptors to drive Drosophila mechanical nociception. Neuron 2022; 110:3727-3742.e8. [PMID: 36087585 DOI: 10.1016/j.neuron.2022.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 06/07/2022] [Accepted: 08/11/2022] [Indexed: 12/15/2022]
Abstract
Mechanical nociception is essential for animal survival. However, the forces involved in nociceptor activation and the underlying mechanotransduction mechanisms remain elusive. Here, we address these problems by investigating nocifensive behavior in Drosophila larvae. We show that strong poking stimulates nociceptors with a mixture of forces including shear stress and stretch. Unexpectedly, nociceptors are selectively activated by shear stress, but not stretch. Both the shear stress responses of nociceptors and nocifensive behavior require transient receptor potential A1 (TrpA1), which is specifically expressed in nociceptors. We further demonstrate that expression of mammalian or Drosophila TrpA1 in heterologous cells confers responses to shear stress but not stretch. Finally, shear stress activates TrpA1 in a membrane-delimited manner, through modulation of membrane fluidity. Together, our study reveals TrpA1 as an evolutionarily conserved mechanosensitive channel specifically activated by shear stress and suggests a critical role of shear stress in activating nociceptors to drive mechanical nociception.
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Affiliation(s)
- Jiaxin Gong
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Jiazhang Chen
- Department of Physics, Worcester Polytechnic Institute, Worcester, MA 01605, USA
| | - Pengyu Gu
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ye Shang
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Neuroscience, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Kendra Takle Ruppell
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Neuroscience, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ying Yang
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Fei Wang
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Neuroscience, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Qi Wen
- Department of Physics, Worcester Polytechnic Institute, Worcester, MA 01605, USA.
| | - Yang Xiang
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Neuroscience, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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17
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Volkmar N, Gawden‐Bone CM, Williamson JC, Nixon‐Abell J, West JA, St George‐Hyslop PH, Kaser A, Lehner PJ. Regulation of membrane fluidity by RNF145-triggered degradation of the lipid hydrolase ADIPOR2. EMBO J 2022; 41:e110777. [PMID: 35993436 PMCID: PMC9531299 DOI: 10.15252/embj.2022110777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 12/19/2022] Open
Abstract
The regulation of membrane lipid composition is critical for cellular homeostasis. Cells are particularly sensitive to phospholipid saturation, with increased saturation causing membrane rigidification and lipotoxicity. How mammalian cells sense membrane lipid composition and reverse fatty acid (FA)-induced membrane rigidification is poorly understood. Here we systematically identify proteins that differ between mammalian cells fed saturated versus unsaturated FAs. The most differentially expressed proteins were two ER-resident polytopic membrane proteins: the E3 ubiquitin ligase RNF145 and the lipid hydrolase ADIPOR2. In unsaturated lipid membranes, RNF145 is stable, promoting its lipid-sensitive interaction, ubiquitination and degradation of ADIPOR2. When membranes become enriched in saturated FAs, RNF145 is rapidly auto-ubiquitinated and degraded, stabilising ADIPOR2, whose hydrolase activity restores lipid homeostasis and prevents lipotoxicity. We therefore identify RNF145 as a FA-responsive ubiquitin ligase which, together with ADIPOR2, defines an autoregulatory pathway that controls cellular membrane lipid homeostasis and prevents acute lipotoxic stress.
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Affiliation(s)
- Norbert Volkmar
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
- Present address:
Institute for Molecular Systems Biology (IMSB)ETH ZürichZürichSwitzerland
| | - Christian M Gawden‐Bone
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | - James C Williamson
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | | | - James A West
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | | | - Arthur Kaser
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
| | - Paul J Lehner
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Jeffrey Cheah Biomedical CentreUniversity of CambridgeCambridgeUK
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18
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Ruiz M, Svensk E, Einarsson E, Grahn EP, Pilon M. A small molecule screen for paqr-2 suppressors identifies Tyloxapol as a membrane fluidizer for C. elegans and mammalian cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183959. [PMID: 35588889 DOI: 10.1016/j.bbamem.2022.183959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 04/20/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Defects in cell membrane homeostasis are implicated in numerous disorders, including cancer, neurodegeneration and diabetes. There is therefore a need for a powerful model to study membrane homeostasis and to identify eventual therapeutic routes. The C. elegans gene paqr-2 encodes a homolog of the mammalian AdipoR1 and AdipoR2 proteins that, when mutated, causes a membrane homeostasis defect accompanied by multiple phenotypes such as intolerance to dietary saturated fatty acids, intolerance to cold and a characteristic tail tip morphology defect. We screened a compound library to identify molecules that can suppress the paqr-2 phenotypes. A single positive hit, Tyloxapol, was found that very effectively suppresses multiple paqr-2 phenotypes. Tyloxapol is a non-ionic detergent currently in use clinically as an expectorant. Importantly, we examined the potential of Tyloxapol as a fluidizer in human cells and found that it improves the viability and membrane fluidity of AdipoR2-deficient human cells challenged with palmitic acid, a membrane-rigidifying saturated fatty acid.
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Affiliation(s)
- Mario Ruiz
- Dept. Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, S-405 30 Gothenburg, Sweden
| | - Emma Svensk
- Dept. Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, S-405 30 Gothenburg, Sweden
| | - Elinor Einarsson
- Dept. Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, S-405 30 Gothenburg, Sweden
| | - Erik Podda Grahn
- Dept. Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, S-405 30 Gothenburg, Sweden
| | - Marc Pilon
- Dept. Chemistry and Molecular Biology, University of Gothenburg, Medicinaregatan 9C, S-405 30 Gothenburg, Sweden.
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19
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Merchant M, Mata CP, Liu Y, Zhai H, Protasio AV, Modis Y. A bioactive phlebovirus-like envelope protein in a hookworm endogenous virus. SCIENCE ADVANCES 2022; 8:eabj6894. [PMID: 35544562 PMCID: PMC9094657 DOI: 10.1126/sciadv.abj6894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 03/25/2022] [Indexed: 05/02/2023]
Abstract
Endogenous viral elements (EVEs), accounting for 15% of our genome, serve as a genetic reservoir from which new genes can emerge. Nematode EVEs are particularly diverse and informative of virus evolution. We identify Atlas virus-an intact retrovirus-like EVE in the human hookworm Ancylostoma ceylanicum, with an envelope protein genetically related to GN-GC glycoproteins from the family Phenuiviridae. A cryo-EM structure of Atlas GC reveals a class II viral membrane fusion protein fold not previously seen in retroviruses. Atlas GC has the structural hallmarks of an active fusogen. Atlas GC trimers insert into membranes with endosomal lipid compositions and low pH. When expressed on the plasma membrane, Atlas GC has cell-cell fusion activity. With its preserved biological activities, Atlas GC has the potential to acquire a cellular function. Our work reveals structural plasticity in reverse-transcribing RNA viruses.
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Affiliation(s)
- Monique Merchant
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Carlos P. Mata
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Yangci Liu
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Haoming Zhai
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
| | - Anna V. Protasio
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
- Christ’s College, University of Cambridge, St Andrew’s Street, Cambridge, CB2 3BU, UK
| | - Yorgo Modis
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
- Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID), University of Cambridge School of Clinical Medicine, Cambridge CB2 0AW, UK
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20
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Fang W, Zhu Y, Yang S, Tong X, Ye C. Reciprocal regulation of phosphatidylcholine synthesis and H3K36 methylation programs metabolic adaptation. Cell Rep 2022; 39:110672. [PMID: 35417718 DOI: 10.1016/j.celrep.2022.110672] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/14/2022] [Accepted: 03/22/2022] [Indexed: 11/17/2022] Open
Abstract
Phospholipid biosynthesis plays a role in mediating membrane-to-histone communication that influences metabolic decisions. Upon nutrient deprivation, phospholipid methylation generates a starvation signal in the form of S-adenosylmethionine (SAM) depletion, leading to dynamic changes in histone methylation. Here we show that the SAM-responsive methylation of H3K36 is critical for metabolic adaptation to nutrient starvation in the budding yeast Saccharomyces cerevisiae. We find that mutants deficient in H3K36 methylation exhibit defects in membrane integrity and pyrimidine metabolism and lose viability quickly under starvation. Adjusting the synthesis of phospholipids potently rewires metabolic pathways for nucleotide synthesis and boosts the production of antioxidants, ameliorating the defects resulting from the loss of H3K36 methylation. We further demonstrate that H3K36 methylation reciprocally regulates phospholipid synthesis by influencing redox balance. Our study illustrates an adaptive mechanism whereby phospholipid synthesis entails a histone modification to reprogram metabolism for adaptation in a eukaryotic model organism.
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Affiliation(s)
- Wen Fang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Yibing Zhu
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Sen Yang
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Xiaomeng Tong
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Cunqi Ye
- Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China; Kidney Disease Center, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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21
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Regulation and functions of membrane lipids: Insights from Caenorhabditis elegans. BBA ADVANCES 2022; 2:100043. [PMID: 37082601 PMCID: PMC10074978 DOI: 10.1016/j.bbadva.2022.100043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/28/2021] [Accepted: 01/12/2022] [Indexed: 02/08/2023] Open
Abstract
The Caenorhabditis elegans plasma membrane is composed of glycerophospholipids and sphingolipids with a small cholesterol. The C. elegans obtain the majority of the membrane lipids by modifying fatty acids present in the bacterial diet. The metabolic pathways of membrane lipid biosynthesis are well conserved across the animal kingdom. In C. elegans CDP-DAG and Kennedy pathway produce glycerophospholipids. Meanwhile, the sphingolipids are synthesized through a different pathway. They have evolved remarkably diverse mechanisms to maintain membrane lipid homeostasis. For instance, the lipid bilayer stress operates to accomplish homeostasis during any perturbance in the lipid composition. Meanwhile, the PAQR-2/IGLR-2 complex works with FLD-1 to balance unsaturated to saturated fatty acids to maintain membrane fluidity. The loss of membrane lipid homeostasis is observed in many human genetic and metabolic disorders. Since C. elegans conserved such genes and pathways, it can be used as a model organism.
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22
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Palm Oil-Rich Diet Affects Murine Liver Proteome and S-Palmitoylome. Int J Mol Sci 2021; 22:ijms222313094. [PMID: 34884899 PMCID: PMC8657750 DOI: 10.3390/ijms222313094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 01/14/2023] Open
Abstract
Palmitic acid (C16:0) is the most abundant saturated fatty acid in animals serving as a substrate in synthesis and β-oxidation of other lipids, and in the modification of proteins called palmitoylation. The influence of dietary palmitic acid on protein S-palmitoylation remains largely unknown. In this study we performed high-throughput proteomic analyses of a membrane-enriched fraction of murine liver to examine the influence of a palm oil-rich diet (HPD) on S-palmitoylation of proteins. HPD feeding for 4 weeks led to an accumulation of C16:0 and C18:1 fatty acids in livers which disappeared after 12-week feeding, in contrast to an accumulation of C16:0 in peritoneal macrophages. Parallel proteomic studies revealed that HPD feeding induced a sequence of changes of the level and/or S-palmitoylation of diverse liver proteins involved in fatty acid, cholesterol and amino acid metabolism, hemostasis, and neutrophil degranulation. The HPD diet did not lead to liver damage, however, it caused progressing obesity, hypercholesterolemia and hyperglycemia. We conclude that the relatively mild negative impact of such diet on liver functioning can be attributed to a lower bioavailability of palm oil-derived C16:0 vs. that of C18:1 and the efficiency of mechanisms preventing liver injury, possibly including dynamic protein S-palmitoylation.
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23
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Ruiz M, Henricsson M, Borén J, Pilon M. Palmitic acid causes increased dihydroceramide levels when desaturase expression is directly silenced or indirectly lowered by silencing AdipoR2. Lipids Health Dis 2021; 20:173. [PMID: 34839823 PMCID: PMC8627610 DOI: 10.1186/s12944-021-01600-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/13/2021] [Indexed: 11/10/2022] Open
Abstract
Background AdipoR1 and AdipoR2 (AdipoRs) are plasma membrane proteins often considered to act as adiponectin receptors with a ceramidase activity. Additionally, the AdipoRs and their yeast and C. elegans orthologs are emerging as membrane homeostasis regulators that counter membrane rigidification by promoting fatty acid desaturation and incorporation of unsaturated fatty acids into phospholipids, thus restoring fluidity. Methods Using cultured cells, the effects of AdipoR silencing or over-expression on the levels and composition of several sphingolipid classes were examined. Results AdipoR2 silencing in the presence of exogenous palmitic acid potently causes increased levels of dihydroceramides, a ceramide precursor in the de novo ceramide synthesis pathway. Conversely, AdipoR2 over-expression caused a depletion of dihydroceramides. Conclusions The results are consistent with AdipoR2 silencing leading to increased intracellular supply of palmitic acid that in turn leads to increased dihydroceramide synthesis via the rate-limiting serine palmitoyl transferase step. In agreement with this model, inhibiting the desaturase SCD or SREBF1/2 (positive regulators of SCD) also causes a strong increase in dihydroceramide levels. Supplementary Information The online version contains supplementary material available at 10.1186/s12944-021-01600-y.
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Affiliation(s)
- Mario Ruiz
- Department Chemistry and Molecular Biology, Univ. Gothenburg, Box 462, 405 30, Gothenburg, Sweden
| | - Marcus Henricsson
- Department Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, Univ. of Gothenburg, 405 30, Gothenburg, Sweden
| | - Jan Borén
- Department Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, Univ. of Gothenburg, 405 30, Gothenburg, Sweden
| | - Marc Pilon
- Department Chemistry and Molecular Biology, Univ. Gothenburg, Box 462, 405 30, Gothenburg, Sweden.
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24
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Pilon M. Paradigm shift: the primary function of the "Adiponectin Receptors" is to regulate cell membrane composition. Lipids Health Dis 2021; 20:43. [PMID: 33931104 PMCID: PMC8088037 DOI: 10.1186/s12944-021-01468-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/18/2021] [Indexed: 12/13/2022] Open
Abstract
The ADIPOR1 and ADIPOR2 proteins (ADIPORs) are generally considered as adiponectin receptors with anti-diabetic properties. However, studies on the yeast and C. elegans homologs of the mammalian ADIPORs, and of the ADIPORs themselves in various mammalian cell models, support an updated/different view. Based on findings in these experimental models, the ADIPORs are now emerging as evolutionarily conserved regulators of membrane homeostasis that do not require adiponectin to act as membrane fluidity sensors and regulate phospholipid composition. More specifically, membrane rigidification activates ADIPOR signaling to promote fatty acid desaturation and incorporation of polyunsaturated fatty acids into membrane phospholipids until fluidity is restored. The present review summarizes the evidence supporting this new view of the ADIPORs, and briefly examines physiological consequences.
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Affiliation(s)
- Marc Pilon
- Dept. Chemistry and Molecular Biology, Univ. Gothenburg, Box 462, S-405 30, Gothenburg, Sweden.
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25
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Devkota R, Henricsson M, Borén J, Pilon M. The C. elegans PAQR-2 and IGLR-2 membrane homeostasis proteins are uniquely essential for tolerating dietary saturated fats. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158883. [PMID: 33444761 DOI: 10.1016/j.bbalip.2021.158883] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/18/2020] [Accepted: 01/06/2021] [Indexed: 01/07/2023]
Abstract
How cells maintain vital membrane lipid homeostasis while obtaining most of their constituent fatty acids from a varied diet remains largely unknown. Here, we report the first whole-organism (Caenorhabditis elegans) forward genetic screen to identify genes essential for tolerance to dietary saturated fatty acids (SFAs). We found that only the PAQR-2/IGLR-2 pathway, homologous to the human adiponectin receptor 2 (AdipoR2) pathway, is uniquely essential to prevent SFA-mediated toxicity. When provided a SFA-rich diet, worms lacking either protein accumulate an excess of SFAs in their membrane phospholipids, which is accompanied by membrane rigidification. Additionally, we used fluorescence resonance energy transfer (FRET) to show that the interaction between PAQR-2 and IGLR-2 is regulated by membrane fluidity, suggesting a mechanism by which this protein complex senses membrane properties. We also created versions of PAQR-2 that lacked parts of the cytoplasmic N-terminal domain and showed that these were still functional, though still dependent on the interaction with IGLR-2. We conclude that membrane homeostasis via the PAQR-2/IGLR-2 fluidity sensor is the only pathway specifically essential for the non-toxic uptake of dietary SFAs in C. elegans.
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Affiliation(s)
- Ranjan Devkota
- Dept. Chemistry and Molecular Biology, Univ. Gothenburg, 405 30 Gothenburg, Sweden
| | - Marcus Henricsson
- Dept. Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, Univ. of Gothenburg, 405 30 Gothenburg, Sweden
| | - Jan Borén
- Dept. Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, Univ. of Gothenburg, 405 30 Gothenburg, Sweden
| | - Marc Pilon
- Dept. Chemistry and Molecular Biology, Univ. Gothenburg, 405 30 Gothenburg, Sweden.
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Ruiz M, Palmgren H, Henricsson M, Devkota R, Jaiswal H, Maresca M, Bohlooly-Y M, Peng XR, Borén J, Pilon M. Extensive transcription mis-regulation and membrane defects in AdipoR2-deficient cells challenged with saturated fatty acids. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158884. [PMID: 33444759 DOI: 10.1016/j.bbalip.2021.158884] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/18/2020] [Accepted: 01/06/2021] [Indexed: 12/24/2022]
Abstract
How cells maintain vital membrane lipid homeostasis while obtaining most of their constituent fatty acids from a varied diet remains largely unknown. Here, we used transcriptomics, lipidomics, growth and respiration assays, and membrane property analyses in human HEK293 cells or human umbilical vein endothelial cells (HUVEC) to show that the function of AdipoR2 is to respond to membrane rigidification by regulating many lipid metabolism genes. We also show that AdipoR2-dependent membrane homeostasis is critical for growth and respiration in cells challenged with saturated fatty acids. Additionally, we found that AdipoR2 deficiency causes transcriptome and cell physiological defects similar to those observed in SREBP-deficient cells upon SFA challenge. Finally, we compared several genes considered important for lipid homeostasis, namely AdipoR2, SCD, FADS2, PEMT and ACSL4, and found that AdipoR2 and SCD are the most important among these to prevent membrane rigidification and excess saturation when human cells are challenged with exogenous SFAs. We conclude that AdipoR2-dependent membrane homeostasis is one of the primary mechanisms that protects against exogenous SFAs.
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Affiliation(s)
- Mario Ruiz
- Dept. Chemistry and Molecular Biology, Univ. Gothenburg, 405 30 Gothenburg, Sweden
| | - Henrik Palmgren
- Metabolism Bioscience, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Marcus Henricsson
- Dept. Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, Univ. of Gothenburg, 405 30 Gothenburg, Sweden
| | - Ranjan Devkota
- Dept. Chemistry and Molecular Biology, Univ. Gothenburg, 405 30 Gothenburg, Sweden
| | - Himjyot Jaiswal
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Gothenburg, Sweden; CellinkAB, Arvid Wallgrens Backe 20, 413 46 Gothenburg, Sweden
| | - Marcello Maresca
- Discovery Biology, Discovery Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | | | - Xiao-Rong Peng
- Metabolism Bioscience, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Jan Borén
- Dept. Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, Univ. of Gothenburg, 405 30 Gothenburg, Sweden
| | - Marc Pilon
- Dept. Chemistry and Molecular Biology, Univ. Gothenburg, 405 30 Gothenburg, Sweden.
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Fatty Acid Composition of the Lipids from Atlantic Salmon-Comparison of Two Extraction Methods without Halogenated Solvents. Foods 2021; 10:foods10010073. [PMID: 33401472 PMCID: PMC7823909 DOI: 10.3390/foods10010073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/28/2020] [Accepted: 12/29/2020] [Indexed: 12/27/2022] Open
Abstract
The scope of this paper was to apply two recently developed methods for lipid extraction: the methyl tert-butyl ether (MTBE) method and the BUME method. These two methods do not include halogenated solvents, which makes them less hazardous to the environment, less toxic, and needed in less volume compared to the standard methods for lipid extraction. Fatty acid composition of the lipids from Atlantic salmon (Salmo salar Linnæus, 1758) was obtained by both procedures. The methods were effective and thirty-three fatty acids were identified. The amounts of the omega-3 polyunsaturated fatty acids obtained by the MTBE method were found to be similar to the overall mean values observed in farmed salmon. The yield of the total lipids obtained by the BUME method was 13% lower. Although the methods involved different solvents, they showed similar fatty acids profile of the lipids from Atlantic salmon. Both methods were validated and some practical challenges were discussed.
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Leveraging a gain-of-function allele of Caenorhabditis elegans paqr-1 to elucidate membrane homeostasis by PAQR proteins. PLoS Genet 2020; 16:e1008975. [PMID: 32750056 PMCID: PMC7428288 DOI: 10.1371/journal.pgen.1008975] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/14/2020] [Accepted: 07/01/2020] [Indexed: 12/12/2022] Open
Abstract
The C. elegans proteins PAQR-2 (a homolog of the human seven-transmembrane domain AdipoR1 and AdipoR2 proteins) and IGLR-2 (a homolog of the mammalian LRIG proteins characterized by a single transmembrane domain and the presence of immunoglobulin domains and leucine-rich repeats in their extracellular portion) form a complex that protects against plasma membrane rigidification by promoting the expression of fatty acid desaturases and the incorporation of polyunsaturated fatty acids into phospholipids, hence increasing membrane fluidity. In the present study, we leveraged a novel gain-of-function allele of PAQR-1, a PAQR-2 paralog, to carry out structure-function studies. We found that the transmembrane domains of PAQR-2 are responsible for its functional requirement for IGLR-2, that PAQR-1 does not require IGLR-2 but acts via the same pathway as PAQR-2, and that the divergent N-terminal cytoplasmic domains of the PAQR-1 and PAQR-2 proteins serve a regulatory function and may regulate access to the catalytic site of these proteins. We also show that overexpression of human AdipoR1 or AdipoR2 alone is sufficient to confer increased palmitic acid resistance in HEK293 cells, and thus act in a manner analogous to the PAQR-1 gain-of-function allele.
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Healthspan pathway maps in C. elegans and humans highlight transcription, proliferation/biosynthesis and lipids. Aging (Albany NY) 2020; 12:12534-12581. [PMID: 32634117 PMCID: PMC7377848 DOI: 10.18632/aging.103514] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/04/2020] [Indexed: 12/17/2022]
Abstract
The molecular basis of aging and of aging-associated diseases is being unraveled at an increasing pace. An extended healthspan, and not merely an extension of lifespan, has become the aim of medical practice. Here, we define health based on the absence of diseases and dysfunctions. Based on an extensive review of the literature, in particular for humans and C. elegans, we compile a list of features of health and of the genes associated with them. These genes may or may not be associated with survival/lifespan. In turn, survival/lifespan genes that are not known to be directly associated with health are not considered. Clusters of these genes based on molecular interaction data give rise to maps of healthspan pathways for humans and for C. elegans. Overlaying healthspan-related gene expression data onto the healthspan pathway maps, we observe the downregulation of (pro-inflammatory) Notch signaling in humans and of proliferation in C. elegans. We identify transcription, proliferation/biosynthesis and lipids as a common theme on the annotation level, and proliferation-related kinases on the gene/protein level. Our literature-based data corpus, including visualization, should be seen as a pilot investigation of the molecular underpinnings of health in two different species. Web address: http://pathways.h2020awe.eu.
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Ruiz M, Bodhicharla R, Ståhlman M, Svensk E, Busayavalasa K, Palmgren H, Ruhanen H, Boren J, Pilon M. Evolutionarily conserved long-chain Acyl-CoA synthetases regulate membrane composition and fluidity. eLife 2019; 8:47733. [PMID: 31769755 PMCID: PMC6901333 DOI: 10.7554/elife.47733] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 11/23/2019] [Indexed: 12/19/2022] Open
Abstract
The human AdipoR1 and AdipoR2 proteins, as well as their C. elegans homolog PAQR-2, protect against cell membrane rigidification by exogenous saturated fatty acids by regulating phospholipid composition. Here, we show that mutations in the C. elegans gene acs-13 help to suppress the phenotypes of paqr-2 mutant worms, including their characteristic membrane fluidity defects. acs-13 encodes a homolog of the human acyl-CoA synthetase ACSL1, and localizes to the mitochondrial membrane where it likely activates long chains fatty acids for import and degradation. Using siRNA combined with lipidomics and membrane fluidity assays (FRAP and Laurdan dye staining) we further show that the human ACSL1 potentiates lipotoxicity by the saturated fatty acid palmitate: silencing ACSL1 protects against the membrane rigidifying effects of palmitate and acts as a suppressor of AdipoR2 knockdown, thus echoing the C. elegans findings. We conclude that acs-13 mutations in C. elegans and ACSL1 knockdown in human cells prevent lipotoxicity by promoting increased levels of polyunsaturated fatty acid-containing phospholipids.
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Affiliation(s)
- Mario Ruiz
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Rakesh Bodhicharla
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Emma Svensk
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Kiran Busayavalasa
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Henrik Palmgren
- Metabolism BioScience, Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Hanna Ruhanen
- Helsinki University Lipidomics Unit, Helsinki Institute for Life Science, Helsinki, Finland.,Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Jan Boren
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marc Pilon
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
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de Mendoza D, Pilon M. Control of membrane lipid homeostasis by lipid-bilayer associated sensors: A mechanism conserved from bacteria to humans. Prog Lipid Res 2019; 76:100996. [DOI: 10.1016/j.plipres.2019.100996] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022]
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Ruiz M, Ståhlman M, Borén J, Pilon M. AdipoR1 and AdipoR2 maintain membrane fluidity in most human cell types and independently of adiponectin. J Lipid Res 2019; 60:995-1004. [PMID: 30890562 PMCID: PMC6495173 DOI: 10.1194/jlr.m092494] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 03/07/2019] [Indexed: 12/16/2022] Open
Abstract
The FA composition of phospholipids must be tightly regulated to maintain optimal cell membrane properties and compensate for a highly variable supply of dietary FAs. Previous studies have shown that AdipoR2 and its homologue PAQR-2 are important regulators of phospholipid FA composition in HEK293 cells and Caenorhabditiselegans, respectively. Here we show that both AdipoR1 and AdipoR2 are essential for sustaining desaturase expression and high levels of unsaturated FAs in membrane phospholipids of many human cell types, including primary human umbilical vein endothelial cells, and for preventing membrane rigidification in cells challenged with exogenous palmitate, a saturated FA. Three independent methods confirm the role of the AdipoRs as regulators of membrane composition and fluidity: fluorescence recovery after photobleaching, measurements of Laurdan dye generalized polarization, and mass spectrometry to determine the FA composition of phospholipids. Furthermore, we show that the AdipoRs can prevent lipotoxicity in the complete absence of adiponectin, their putative ligand. We propose that the primary cellular function of AdipoR1 and AdipoR2 is to maintain membrane fluidity in most human cell types and that adiponectin is not required for this function.
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Affiliation(s)
- Mario Ruiz
- Department of Chemistry and Molecular Biology; University of Gothenburg, Gothenburg, Sweden
| | - Marcus Ståhlman
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Jan Borén
- Department of Molecular and Clinical Medicine/Wallenberg Laboratory Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marc Pilon
- Department of Chemistry and Molecular Biology; University of Gothenburg, Gothenburg, Sweden.
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