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Castañeda-Sánchez CY, Chimal-Vega B, León-Gutiérrez R, Araiza-Robles AE, Serafín-Higuera N, Pulido-Capiz A, Rivero IA, Díaz-Molina R, Alatorre-Meda M, Rodríguez-Velázquez E, García-González V. Low-Density Lipoproteins Increase Proliferation, Invasion, and Chemoresistance via an Exosome Autocrine Mechanism in MDA-MB-231 Chemoresistant Cells. Biomedicines 2024; 12:742. [PMID: 38672098 PMCID: PMC11048396 DOI: 10.3390/biomedicines12040742] [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: 12/23/2023] [Revised: 03/01/2024] [Accepted: 03/07/2024] [Indexed: 04/28/2024] Open
Abstract
Dyslipidemias involving high concentrations of low-density lipoproteins (LDLs) increase the risk of developing triple-negative breast cancer (TNBC), wherein cholesterol metabolism and protein translation initiation mechanisms have been linked with chemoresistance. Doxorubicin (Dox) treatment, a member of the anthracycline family, represents a typical therapeutic strategy; however, chemoresistance remains a significant challenge. Exosomes (Exs) secreted by tumoral cells have been implicated in cell communication pathways and chemoresistance mechanisms; the content of exosomes is an outcome of cellular cholesterol metabolism. We previously induced Dox resistance in TNBC cell models, characterizing a variant denominated as variant B cells. Our results suggest that LDL internalization in parental and chemoresistant variant B cells is associated with increased cell proliferation, migration, invasion, and spheroid growth. We identified the role of eIF4F translation initiation factor and the down-regulation of tumor suppressor gene PDCD4, an inhibitor of eIF4A, in chemoresistant variant B cells. In addition, the exomes secreted by variant B cells were characterized by the protein content, electronic microscopy, and cell internalization assays. Critically, exosomes purified from LDL-treated variant B cell promoted cell proliferation, migration, and an increment in lactate concentration. Our results suggest that an autocrine phenomenon induced by exosomes in chemoresistant cells may induce modifications on signaling mechanisms of the p53/Mdm2 axis and activation of p70 ribosomal protein kinase S6. Moreover, the specific down-regulated profile of chaperones Hsp90 and Hsp70 secretion inside the exosomes of the chemoresistant variant could be associated with this phenomenon. Therefore, autocrine activation mediated by exosomes and the effect of LDL internalization may influence changes in exosome chaperone content and modulate proliferative signaling pathways, increasing the aggressiveness of MDA-MB-231 chemoresistant cells.
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Affiliation(s)
- César Y. Castañeda-Sánchez
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
| | - Brenda Chimal-Vega
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
| | - Roberto León-Gutiérrez
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
| | - Adrián Ernesto Araiza-Robles
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
| | - Nicolás Serafín-Higuera
- Facultad de Odontología Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico;
| | - Angel Pulido-Capiz
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
| | - Ignacio A. Rivero
- Centro de Graduados e Investigación en Química, Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, Tijuana 22510, Mexico;
| | - Raúl Díaz-Molina
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
| | - Manuel Alatorre-Meda
- Centro de Graduados e Investigación en Química-Grupo de Biomateriales y Nanomedicina, CONAHCYT-Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, Tijuana 22510, Mexico;
| | - Eustolia Rodríguez-Velázquez
- Facultad de Odontología, Universidad Autónoma de Baja California, Tijuana 22390, Mexico;
- Centro de Graduados e Investigación en Química-Grupo de Biomateriales y Nanomedicina, Tecnológico Nacional de México, Instituto Tecnológico de Tijuana, Tijuana 22510, Mexico
| | - Victor García-González
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, Mexico; (C.Y.C.-S.); (B.C.-V.); (R.L.-G.); (A.E.A.-R.); (A.P.-C.); (R.D.-M.)
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Universidad Autónoma de Baja California, Mexicali 21000, Mexico
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Wang Y, Nguyen HP, Xue P, Xie Y, Yi D, Lin F, Dinh J, Viscarra JA, Ibe NU, Duncan RE, Sul HS. ApoL6 associates with lipid droplets and disrupts Perilipin1-HSL interaction to inhibit lipolysis. Nat Commun 2024; 15:186. [PMID: 38167864 PMCID: PMC10762002 DOI: 10.1038/s41467-023-44559-3] [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: 10/26/2022] [Accepted: 12/18/2023] [Indexed: 01/05/2024] Open
Abstract
Adipose tissue stores triacylglycerol (TAG) in lipid droplets (LD) and release fatty acids upon lipolysis during energy shortage. We identify ApoL6 as a LD-associated protein mainly found in adipose tissue, specifically in adipocytes. ApoL6 expression is low during fasting but induced upon feeding. ApoL6 knockdown results in smaller LD with lower TAG content in adipocytes, while ApoL6 overexpression causes larger LD with higher TAG content. We show that the ApoL6 affects adipocytes through inhibition of lipolysis. While ApoL6, Perilipin 1 (Plin1), and HSL can form a complex on LD, C-terminal ApoL6 directly interacts with N-terminal Plin1 to prevent Plin1 binding to HSL, to inhibit lipolysis. Thus, ApoL6 ablation decreases white adipose tissue mass, protecting mice from diet-induced obesity, while ApoL6 overexpression in adipose brings obesity and insulin resistance, making ApoL6 a potential future target against obesity and diabetes.
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Affiliation(s)
- Yuhui Wang
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Hai P Nguyen
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Pengya Xue
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Ying Xie
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Danielle Yi
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Frances Lin
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Jennie Dinh
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Jose A Viscarra
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Nnejiuwa U Ibe
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Robin E Duncan
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON, N2T 2N4, Canada
| | - Hei S Sul
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, 94720, USA.
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3
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Jing S, Huang Y, Chen Y, He X, Chen Z, Lu X, Wu M, Wanger TC. Non-Destructive Extraction and Separation of Nano- and Microplastics from Environmental Samples by Density Gradient Ultracentrifugation. Anal Chem 2022; 94:15280-15287. [DOI: 10.1021/acs.analchem.2c02543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Siyuan Jing
- Department of Environmental Science and Engineering, Fudan University, 200438 Shanghai, China
- Sustainable Agricultural Systems & Engineering lab, School of Engineering, Westlake University, Hangzhou, 310024 Zhejiang Province, China
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, 310024 Zhejiang Province, China
| | - Yu Huang
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou, 310024 Zhejiang Province, China
| | - Yinjuan Chen
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou, 310024 Zhejiang Province, China
| | - Xueqing He
- Sustainable Agricultural Systems & Engineering lab, School of Engineering, Westlake University, Hangzhou, 310024 Zhejiang Province, China
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, 310024 Zhejiang Province, China
- ChinaRiceNetwork.org, Hangzhou, 310024 Zhejiang Province, China
| | - Zhong Chen
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou, 310024 Zhejiang Province, China
| | - Xingyu Lu
- Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science, Instrumentation and Service Center for Molecular Sciences, Westlake University, Hangzhou, 310024 Zhejiang Province, China
| | - Minghuo Wu
- School of Ocean Science and Technology, Dalian University of Technology, 124221 Panjin, China
| | - Thomas C. Wanger
- Sustainable Agricultural Systems & Engineering lab, School of Engineering, Westlake University, Hangzhou, 310024 Zhejiang Province, China
- Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, 18 Shilongshan Road, Hangzhou, 310024 Zhejiang Province, China
- ChinaRiceNetwork.org, Hangzhou, 310024 Zhejiang Province, China
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Guevara-Olaya L, Chimal-Vega B, Castañeda-Sánchez CY, López-Cossio LY, Pulido-Capiz A, Galindo-Hernández O, Díaz-Molina R, Ruiz Esparza-Cisneros J, García-González V. LDL Promotes Disorders in β-Cell Cholesterol Metabolism, Implications on Insulin Cellular Communication Mediated by EVs. Metabolites 2022; 12:754. [PMID: 36005626 PMCID: PMC9415214 DOI: 10.3390/metabo12080754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 12/01/2022] Open
Abstract
Dyslipidemia is described as a hallmark of metabolic syndrome, promoting a stage of metabolic inflammation (metainflammation) that could lead to misbalances in energetic metabolism, contributing to insulin resistance, and modifying intracellular cholesterol pathways and the renin-angiotensin system (RAS) in pancreatic islets. Low-density lipoprotein (LDL) hypercholesterolemia could disrupt the tissue communication between Langerhans β-cells and hepatocytes, wherein extracellular vesicles (EVs) are secreted by β-cells, and exposition to LDL can impair these phenomena. β-cells activate compensatory mechanisms to maintain insulin and metabolic homeostasis; therefore, the work aimed to characterize the impact of LDL on β-cell cholesterol metabolism and the implication on insulin secretion, connected with the regulation of cellular communication mediated by EVs on hepatocytes. Our results suggest that β-cells can endocytose LDL, promoting an increase in de novo cholesterol synthesis targets. Notably, LDL treatment increased mRNA levels and insulin secretion; this hyperinsulinism condition was associated with the transcription factor PDX-1. However, a compensatory response that maintains basal levels of intracellular calcium was described, mediated by the overexpression of calcium targets PMCA1/4, SERCA2, and NCX1, together with the upregulation of the unfolded protein response (UPR) through the activation of IRE1 and PERK arms to maintain protein homeostasis. The LDL treatment induced metainflammation by IL-6, NF-κB, and COX-2 overexpression. Furthermore, LDL endocytosis triggered an imbalance of the RAS components. LDL treatment increased the intracellular levels of cholesterol on lipid droplets; the adaptive β-cell response was portrayed by the overexpression of cholesterol transporters ABCA1 and ABCG1. Therefore, lipotoxicity and hyperinsulinism induced by LDL were regulated by the natural compound auraptene, a geranyloxyn coumarin modulator of cholesterol-esterification by ACAT1 enzyme inhibition. EVs isolated from β-cells impaired insulin signaling via mTOR/p70S6Kα in hepatocytes, a phenomenon regulated by auraptene. Our results show that LDL overload plays a novel role in hyperinsulinism, mechanisms associated with a dysregulation of intracellular cholesterol, lipotoxicity, and the adaptive UPR, which may be regulated by coumarin-auraptene; these conditions explain the affectations that occur during the initial stages of insulin resistance.
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Affiliation(s)
- Lizbeth Guevara-Olaya
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
| | - Brenda Chimal-Vega
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
| | - César Yahel Castañeda-Sánchez
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
| | - Leslie Y. López-Cossio
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
| | - Angel Pulido-Capiz
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio de Biología Molecular, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
| | - Octavio Galindo-Hernández
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
| | - Raúl Díaz-Molina
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
| | | | - Victor García-González
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, Mexicali 21000, BC, Mexico
- Laboratorio Multidisciplinario de Estudios Metabólicos y Cáncer, Facultad de Medicina Mexicali, Universidad Autónoma de BC, Mexicali 21000, BC, Mexico
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Anunciado-Koza RP, Stohn JP, Hernandez A, Koza RA. Social and maternal behavior in mesoderm specific transcript (Mest)-deficient mice. PLoS One 2022; 17:e0271913. [PMID: 35867696 PMCID: PMC9307168 DOI: 10.1371/journal.pone.0271913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 07/08/2022] [Indexed: 11/23/2022] Open
Abstract
Mesoderm specific transcript (Mest)/paternally expressed gene-1 (Peg1) is an imprinted gene expressed predominantly from the paternal allele. Aberrations in maternal behavior were previously reported in a Mest global knockout mouse (Mesttm1Masu). In this study, we performed in-depth social and maternal behavioral testing in a mouse model of Mest inactivation developed in our laboratory (Mesttm1.2Rkz). Mice with paternal allele inactivation (MestpKO) did not show anxiety after testing in the elevated plus maze, open field trial, and marble burying; nor depression-like behaviors in the tail suspension test. MestpKO showed normal social behaviors and memory/cognition in the three-chamber box test and the novel object recognition test, respectively. Primiparous MestpKO and MestgKO (biallelic Mest inactivation) female mice exhibited normal nest building and maternal behavior; and, virgin MestpKO and MestgKO female mice showed normal maternal instinct. Analyses of gene expression in adult hypothalamus, embryonic day 14.5 whole brain and adult whole brain demonstrated full abrogation of Mest mRNA in MestpKO and MestgKO mice with no effect on miR-335 expression. Our data indicates no discernible impairments in object recognition memory, social behavior or maternal behavior resulting from loss of Mest. The basis for the differences in maternal phenotypic behaviors between Mesttm1Masu and Mesttm1.2Rkz is not known.
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Affiliation(s)
- Rea P. Anunciado-Koza
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
| | - J. Patrizia Stohn
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
| | - Arturo Hernandez
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
- Department of Medicine, Tufts University School of Medicine, Boston, MA, United States of America
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, United States of America
| | - Robert A. Koza
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine, United States of America
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, United States of America
- Pennington Biomedical Research Center, Baton Rouge, LA, United States of America
- * E-mail:
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Zembroski AS, Andolino C, Buhman KK, Teegarden D. Proteomic Characterization of Cytoplasmic Lipid Droplets in Human Metastatic Breast Cancer Cells. Front Oncol 2021; 11:576326. [PMID: 34141606 PMCID: PMC8204105 DOI: 10.3389/fonc.2021.576326] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 05/10/2021] [Indexed: 12/19/2022] Open
Abstract
One of the characteristic features of metastatic breast cancer is increased cellular storage of neutral lipid in cytoplasmic lipid droplets (CLDs). CLD accumulation is associated with increased cancer aggressiveness, suggesting CLDs contribute to metastasis. However, how CLDs contribute to metastasis is not clear. CLDs are composed of a neutral lipid core, a phospholipid monolayer, and associated proteins. Proteins that associate with CLDs regulate both cellular and CLD metabolism; however, the proteome of CLDs in metastatic breast cancer and how these proteins may contribute to breast cancer progression is unknown. Therefore, the purpose of this study was to identify the proteome and assess the characteristics of CLDs in the MCF10CA1a human metastatic breast cancer cell line. Utilizing shotgun proteomics, we identified over 1500 proteins involved in a variety of cellular processes in the isolated CLD fraction. Interestingly, unlike other cell lines such as adipocytes or enterocytes, the most enriched protein categories were involved in cellular processes outside of lipid metabolism. For example, cell-cell adhesion was the most enriched category of proteins identified, and many of these proteins have been implicated in breast cancer metastasis. In addition, we characterized CLD size and area in MCF10CA1a cells using transmission electron microscopy. Our results provide a hypothesis-generating list of potential players in breast cancer progression and offers a new perspective on the role of CLDs in cancer.
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Affiliation(s)
- Alyssa S Zembroski
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States
| | - Chaylen Andolino
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States
| | - Dorothy Teegarden
- Department of Nutrition Science, Purdue University, West Lafayette, IN, United States
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Whytock KL, Parry SA, Turner MC, Woods RM, James LJ, Ferguson RA, Ståhlman M, Borén J, Strauss JA, Cocks M, Wagenmakers AJM, Hulston CJ, Shepherd SO. A 7‐day high‐fat, high‐calorie diet induces fibre‐specific increases in intramuscular triglyceride and perilipin protein expression in human skeletal muscle. J Physiol 2020; 598:1151-1167. [DOI: 10.1113/jp279129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 01/13/2020] [Indexed: 12/24/2022] Open
Affiliation(s)
- K. L. Whytock
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - S. A. Parry
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - M. C. Turner
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - R. M. Woods
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - L. J. James
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - R. A. Ferguson
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - M. Ståhlman
- Wallenberg Laboratory, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - J. Borén
- Wallenberg Laboratory, Sahlgrenska Academy University of Gothenburg Gothenburg Sweden
| | - J. A. Strauss
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - M. Cocks
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - A. J. M. Wagenmakers
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
| | - C. J. Hulston
- School of Sport, Exercise and Health Sciences Loughborough University Loughborough LE11 3TU UK
| | - S. O. Shepherd
- Research Institute of Sport and Exercise Science, Tom Reilly Building LJMU Liverpool L3 3AF UK
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8
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Nguyen HP, Yi D, Lin F, Viscarra JA, Tabuchi C, Ngo K, Shin G, Lee AYF, Wang Y, Sul HS. Aifm2, a NADH Oxidase, Supports Robust Glycolysis and Is Required for Cold- and Diet-Induced Thermogenesis. Mol Cell 2020; 77:600-617.e4. [PMID: 31952989 PMCID: PMC7031813 DOI: 10.1016/j.molcel.2019.12.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 09/10/2019] [Accepted: 12/03/2019] [Indexed: 01/22/2023]
Abstract
Brown adipose tissue (BAT) is highly metabolically active tissue that dissipates energy via UCP1 as heat, and BAT mass is correlated negatively with obesity. The presence of BAT/BAT-like tissue in humans renders BAT as an attractive target against obesity and insulin resistance. Here, we identify Aifm2, a NADH oxidoreductase domain containing flavoprotein, as a lipid droplet (LD)-associated protein highly enriched in BAT. Aifm2 is induced by cold as well as by diet. Upon cold or β-adrenergic stimulation, Aifm2 associates with the outer side of the mitochondrial inner membrane. As a unique BAT-specific first mammalian NDE (external NADH dehydrogenase)-like enzyme, Aifm2 oxidizes NADH to maintain high cytosolic NAD levels in supporting robust glycolysis and to transfer electrons to the electron transport chain (ETC) for fueling thermogenesis. Aifm2 in BAT and subcutaneous white adipose tissue (WAT) promotes oxygen consumption, uncoupled respiration, and heat production during cold- and diet-induced thermogenesis. Aifm2, thus, can ameliorate diet-induced obesity and insulin resistance.
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Affiliation(s)
- Hai P Nguyen
- Endocrinology Program, University of California, Berkeley, Berkeley, CA, USA; Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Danielle Yi
- Endocrinology Program, University of California, Berkeley, Berkeley, CA, USA; Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Frances Lin
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Jose A Viscarra
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Chihiro Tabuchi
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Katina Ngo
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Gawon Shin
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Angus Yiu-Fai Lee
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Yuhui Wang
- Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - Hei Sook Sul
- Endocrinology Program, University of California, Berkeley, Berkeley, CA, USA; Department of Nutritional Sciences & Toxicology, University of California, Berkeley, Berkeley, CA, USA.
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9
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Acosta-Montaño P, Rodríguez-Velázquez E, Ibarra-López E, Frayde-Gómez H, Mas-Oliva J, Delgado-Coello B, Rivero IA, Alatorre-Meda M, Aguilera J, Guevara-Olaya L, García-González V. Fatty Acid and Lipopolysaccharide Effect on Beta Cells Proteostasis and its Impact on Insulin Secretion. Cells 2019; 8:cells8080884. [PMID: 31412623 PMCID: PMC6721695 DOI: 10.3390/cells8080884] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/02/2019] [Accepted: 08/06/2019] [Indexed: 02/07/2023] Open
Abstract
Metabolic overload by saturated fatty acids (SFA), which comprises β-cell function, and impaired glucose-stimulated insulin secretion are frequently observed in patients suffering from obesity and type 2 diabetes mellitus. The increase of intracellular Ca2+ triggers insulin granule release, therefore several mechanisms regulate Ca2+ efflux within the β-cells, among others, the plasma membrane Ca2+-ATPase (PMCA). In this work, we describe that lipotoxicity mediated mainly by the saturated palmitic acid (PA) (16C) is associated with loss of protein homeostasis (proteostasis) and potentially cell viability, a phenomenon that was induced to a lesser extent by stearic (18C), myristic (14C) and lauric (12C) acids. PA was localized on endoplasmic reticulum, activating arms of the unfolded protein response (UPR), as also promoted by lipopolysaccharides (LPS)-endotoxins. In particular, our findings demonstrate an alteration in PMCA1/4 expression caused by PA and LPS which trigger the UPR, affecting not only insulin release and contributing to β-cell mass reduction, but also increasing reactive nitrogen species. Nonetheless, stearic acid (SA) did not show these effects. Remarkably, the proteolytic degradation of PMCA1/4 prompted by PA and LPS was avoided by the action of monounsaturated fatty acids such as oleic and palmitoleic acid. Oleic acid recovered cell viability after treatment with PA/LPS and, more interestingly, relieved endoplasmic reticulum (ER) stress. While palmitoleic acid improved the insulin release, this fatty acid seems to have more relevant effects upon the expression of regulatory pumps of intracellular Ca2+. Therefore, chain length and unsaturation of fatty acids are determinant cues in proteostasis of β-cells and, consequently, on the regulation of calcium and insulin secretion.
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Affiliation(s)
- Paloma Acosta-Montaño
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, 21000 Mexicali, Mexico
| | - Eustolia Rodríguez-Velázquez
- Facultad de Odontología, Universidad Autónoma de Baja California, 22390 Tijuana, Mexico
- Tecnológico Nacional de México/I.T. Tijuana, Centro de Graduados e Investigación en Química-Grupo de Biomateriales y Nanomedicina, 22510 Tijuana, Mexico
| | - Esmeralda Ibarra-López
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, 21000 Mexicali, Mexico
| | - Héctor Frayde-Gómez
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, 21000 Mexicali, Mexico
- Hospital General de Zona No. 30, Instituto Mexicano del Seguro Social, 21100 Mexicali, Mexico
| | - Jaime Mas-Oliva
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad de México, Mexico
| | - Blanca Delgado-Coello
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Ciudad de México, Mexico
| | - Ignacio A Rivero
- Tecnológico Nacional de México/I.T. Tijuana, Centro de Graduados e Investigación en Química, 22000 Tijuana, Mexico
| | - Manuel Alatorre-Meda
- Cátedras CONACyT- Tecnológico Nacional de México/I.T. Tijuana. Centro de Graduados e Investigación en Química-Grupo de Biomateriales y Nanomedicina, 22000 Tijuana, Mexico
| | - Jorge Aguilera
- Tecnológico Nacional de México/I.T. Tijuana, Centro de Graduados e Investigación en Química, 22000 Tijuana, Mexico
| | - Lizbeth Guevara-Olaya
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, 21000 Mexicali, Mexico
| | - Victor García-González
- Departamento de Bioquímica, Facultad de Medicina Mexicali, Universidad Autónoma de Baja California, 21000 Mexicali, Mexico.
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10
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Abstract
Lipid droplets (LDs) are ubiquitous lipid storage organelles composed of a neutral lipid core surrounded by a phospholipid monolayer that is decorated with integral and peripheral proteins. Accurate identification of LD proteins using biochemical fractionation methods has been challenging due to the presence of contaminant proteins from co-fractionating organelles. Here, we describe a method to identify high-confidence LD proteomes that employs an engineered ascorbate peroxidase (APEX2) to induce spatially and temporally restricted biotinylation of LD proteins. This proximity labeling method can be broadly applied to define the composition of the LD proteome in any cultured cell line and can be utilized to examine LD proteome dynamics.
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11
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Gao H, Yang Z, Wang X, Qian P, Hong R, Chen X, Su XZ, Cui H, Yuan J. ISP1-Anchored Polarization of GCβ/CDC50A Complex Initiates Malaria Ookinete Gliding Motility. Curr Biol 2018; 28:2763-2776.e6. [PMID: 30146157 DOI: 10.1016/j.cub.2018.06.069] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/28/2018] [Accepted: 06/26/2018] [Indexed: 12/20/2022]
Abstract
Ookinete gliding motility is essential for penetration of the mosquito midgut wall and transmission of malaria parasites. Cyclic guanosine monophosphate (cGMP) signaling has been implicated in ookinete gliding. However, the upstream mechanism of how the parasites activate cGMP signaling and thus initiate ookinete gliding remains unknown. Using real-time imaging to visualize Plasmodium yoelii guanylate cyclase β (GCβ), we show that cytoplasmic GCβ translocates and polarizes to the parasite plasma membrane at "ookinete extrados site" (OES) during zygote-to-ookinete differentiation. The polarization of enzymatic active GCβ at OES initiates gliding of matured ookinete. Both the P4-ATPase-like domain and guanylate cyclase domain are required for GCβ polarization and ookinete gliding. CDC50A, a co-factor of P4-ATPase, binds to and stabilizes GCβ during ookinete development. Screening of inner membrane complex proteins identifies ISP1 as a key molecule that anchors GCβ/CDC50A complex at the OES of mature ookinetes. This study defines a spatial-temporal mechanism for the initiation of ookinete gliding, where GCβ polarization likely elevates local cGMP levels and activates cGMP-dependent protein kinase signaling.
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Affiliation(s)
- Han Gao
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhenke Yang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xu Wang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Pengge Qian
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Renjie Hong
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xin Chen
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xin-Zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Huiting Cui
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Jing Yuan
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China.
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12
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Prudovsky I, Anunciado-Koza RP, Jacobs CG, Kacer D, Siviski ME, Koza RA. Mesoderm-specific transcript localization in the ER and ER-lipid droplet interface supports a role in adipocyte hypertrophy. J Cell Biochem 2017; 119:2636-2645. [PMID: 29058774 DOI: 10.1002/jcb.26429] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/17/2017] [Indexed: 01/16/2023]
Abstract
Highly variable expression of mesoderm-specific transcript (Mest) in adipose tissue among genetically homogeneous mice fed an obesogenic diet, and its positive association with fat mass expansion, suggests that Mest is an epigenetic determinant for the development of obesity. Although the mechanisms by which MEST augments fat accumulation in adipocytes have not been elucidated, it has sequence homology and catalytic peptide motifs which suggests that it functions as an epoxide hydrolase or as a glycerol- or acylglycerol-3-phosphate acyltransferase. To better understand MEST function, detailed studies were performed to precisely define the intracellular organelle localization of MEST using immunofluorescence confocal microscopy. Lentiviral-mediated expression of a C-terminus Myc-DDK-tagged MEST fusion protein expressed in 3T3-L1 preadipocytes/adipocytes, and ear-derived mesenchymal stem cells (EMSC) from mice was observed in the endoplasmic reticulum (ER) membranes and is consistent with previous studies showing endogenous MEST in the membrane fraction of adipose tissue. MEST was not associated with the Golgi apparatus or mitochondria; however, frequent contacts were observed between MEST-positive ER and mitochondria. MEST-positive domains were also shown on the plasma membrane (PM) of non-permeabilized cells but they did not co-localize with ER-PM bridges. Post-adipogenic differentiated 3T3-L1 adipocytes and EMSC showed significant co-localization of MEST with the lipid droplet surface marker perilipin at contact points between the ER and lipid droplet. Identification of MEST as an ER-specific protein that co-localizes with lipid droplets in cells undergoing adipogenic differentiation supports a function for MEST in the facilitation of lipid accumulation and storage in adipocytes.
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Affiliation(s)
- Igor Prudovsky
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine.,The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine
| | - Rea P Anunciado-Koza
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine
| | - Chester G Jacobs
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine
| | - Doreen Kacer
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine
| | - Matthew E Siviski
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine.,The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine
| | - Robert A Koza
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine.,The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine
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13
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Hung YH, Carreiro AL, Buhman KK. Dgat1 and Dgat2 regulate enterocyte triacylglycerol distribution and alter proteins associated with cytoplasmic lipid droplets in response to dietary fat. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:600-614. [PMID: 28249764 PMCID: PMC5503214 DOI: 10.1016/j.bbalip.2017.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/31/2017] [Accepted: 02/24/2017] [Indexed: 12/16/2022]
Abstract
Enterocytes, the absorptive cells of the small intestine, mediate efficient absorption of dietary fat (triacylglycerol, TAG). The digestive products of dietary fat are taken up by enterocytes, re-esterified into TAG, and packaged on chylomicrons (CMs) for secretion into blood or temporarily stored within cytoplasmic lipid droplets (CLDs). Altered enterocyte TAG distribution impacts susceptibility to high fat diet associated diseases, but molecular mechanisms directing TAG toward these fates are unclear. Two enzymes, acyl CoA: diacylglycerol acyltransferase 1 (Dgat1) and Dgat2, catalyze the final, committed step of TAG synthesis within enterocytes. Mice with intestine-specific overexpression of Dgat1 (Dgat1Int) or Dgat2 (Dgat2Int), or lack of Dgat1 (Dgat1-/-), were previously found to have altered intestinal TAG secretion and storage. We hypothesized that varying intestinal Dgat1 and Dgat2 levels alters TAG distribution in subcellular pools for CM synthesis as well as the morphology and proteome of CLDs. To test this we used ultrastructural and proteomic methods to investigate intracellular TAG distribution and CLD-associated proteins in enterocytes from Dgat1Int, Dgat2Int, and Dgat1-/- mice 2h after a 200μl oral olive oil gavage. We found that varying levels of intestinal Dgat1 and Dgat2 altered TAG pools involved in CM assembly and secretion, the number or size of CLDs present in enterocytes, and the enterocyte CLD proteome. Overall, these results support a model where Dgat1 and Dgat2 function coordinately to regulate the process of dietary fat absorption by preferentially synthesizing TAG for incorporation into distinct subcellular TAG pools in enterocytes.
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Affiliation(s)
- Yu-Han Hung
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Alicia L Carreiro
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Kimberly K Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA.
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14
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Ferguson D, Zhang J, Davis MA, Helsley RN, Vedin LL, Lee RG, Crooke RM, Graham MJ, Allende DS, Parini P, Brown JM. The lipid droplet-associated protein perilipin 3 facilitates hepatitis C virus-driven hepatic steatosis. J Lipid Res 2016; 58:420-432. [PMID: 27941027 DOI: 10.1194/jlr.m073734] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Indexed: 12/18/2022] Open
Abstract
Hepatitis C virus (HCV) is an enveloped RNA virus responsible for 170 million cases of viral hepatitis worldwide. Over 50% of chronically infected HCV patients develop hepatic steatosis, and steatosis can be induced by expression of HCV core protein (core) alone. Additionally, core must associate with cytoplasmic lipid droplets (LDs) for steatosis development and viral particle assembly. Due to the importance of the LD as a key component of hepatic lipid storage and as a platform for HCV particle assembly, it seems this dynamic subcellular organelle is a gatekeeper in the pathogenesis of viral hepatitis. Here, we hypothesized that core requires the host LD scaffold protein, perilipin (PLIN)3, to induce hepatic steatosis. To test our hypothesis in vivo, we have studied core-induced hepatic steatosis in the absence or presence of antisense oligonucleotide-mediated knockdown of PLIN3. PLIN3 knockdown blunted HCV core-induced steatosis in transgenic mice fed either chow or a moderate fat diet. Collectively, our studies demonstrate that the LD scaffold protein, PLIN3, is essential for HCV core-induced hepatic steatosis and provide new insights into the pathogenesis of HCV.
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Affiliation(s)
- Daniel Ferguson
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH.,Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Jun Zhang
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Matthew A Davis
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Robert N Helsley
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
| | - Lise-Lotte Vedin
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Richard G Lee
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Rosanne M Crooke
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - Mark J Graham
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | | | - Paolo Parini
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
| | - J Mark Brown
- Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH
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15
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Urrutia RA, Kalinec F. Biology and pathobiology of lipid droplets and their potential role in the protection of the organ of Corti. Hear Res 2015; 330:26-38. [PMID: 25987503 PMCID: PMC5391798 DOI: 10.1016/j.heares.2015.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 12/20/2022]
Abstract
The current review article seeks to extend our understanding on the role of lipid droplets within the organ of Corti. In addition to presenting an overview of the current information about the origin, structure and function of lipid droplets we draw inferences from the collective body of knowledge about this cellular organelle to build a conceptual framework to better understanding their role in auditory function. This conceptual model considers that lipid droplets play a significant role in the synthesis, storage, and release of lipids and proteins for energetic use and/or modulating cell signaling pathways. We describe the role and mechanism by which LD play a role in human diseases, and we also review emerging data from our laboratory revealing the potential role of lipid droplets from Hensen cells in the auditory organ. We suggest that lipid droplets might help to develop rapidly and efficiently the resolution phase of inflammatory responses in the mammalian cochlea, preventing inflammatory damage of the delicate inner ear structures and, consequently, sensorineural hearing loss.
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Affiliation(s)
- Raul A Urrutia
- Epigenetics and Chromatin Dynamics Laboratory, Translational Epigenomic Program, Center for Individualized Medicine (CIM) Mayo Clinic, Rochester, MN 55905, USA
| | - Federico Kalinec
- Laboratory of Auditory Cell Biology, Department of Head & Neck Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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16
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Hall AM, Soufi N, Chambers KT, Chen Z, Schweitzer GG, McCommis KS, Erion DM, Graham MJ, Su X, Finck BN. Abrogating monoacylglycerol acyltransferase activity in liver improves glucose tolerance and hepatic insulin signaling in obese mice. Diabetes 2014; 63:2284-96. [PMID: 24595352 PMCID: PMC4066334 DOI: 10.2337/db13-1502] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Monoacylglycerol acyltransferase (MGAT) enzymes convert monoacylglycerol to diacylglycerol (DAG), a lipid that has been linked to the development of hepatic insulin resistance through activation of protein kinase C (PKC). The expression of genes that encode MGAT enzymes is induced in the livers of insulin-resistant human subjects with nonalcoholic fatty liver disease, but whether MGAT activation is causal of hepatic steatosis or insulin resistance is unknown. We show that the expression of Mogat1, which encodes MGAT1, and MGAT activity are also increased in diet-induced obese (DIO) and ob/obmice. To probe the metabolic effects of MGAT1 in the livers of obese mice, we administered antisense oligonucleotides (ASOs) against Mogat1 to DIO and ob/ob mice for 3 weeks. Knockdown of Mogat1 in liver, which reduced hepatic MGAT activity, did not affect hepatic triacylglycerol content and unexpectedly increased total DAG content. Mogat1 inhibition also increased both membrane and cytosolic compartment DAG levels. However, Mogat1 ASO treatment significantly improved glucose tolerance and hepatic insulin signaling in obese mice. In summary, inactivation of hepatic MGAT activity, which is markedly increased in obese mice, improved glucose tolerance and hepatic insulin signaling independent of changes in body weight, intrahepatic DAG and TAG content, and PKC signaling.
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Affiliation(s)
- Angela M Hall
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Nisreen Soufi
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Kari T Chambers
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Zhouji Chen
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - George G Schweitzer
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Kyle S McCommis
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
| | - Derek M Erion
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Global Research and Development, Cambridge, MA
| | | | - Xiong Su
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MODepartment of Biochemistry and Molecular Biology, Medical College of Soochow University, Suzhou, China
| | - Brian N Finck
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO
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17
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Skinner JR, Harris LAL, Shew TM, Abumrad NA, Wolins NE. Perilipin 1 moves between the fat droplet and the endoplasmic reticulum. Adipocyte 2013; 2:80-6. [PMID: 23805403 PMCID: PMC3661117 DOI: 10.4161/adip.22864] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/08/2012] [Accepted: 11/09/2012] [Indexed: 11/19/2022] Open
Abstract
Perilipin 1, unlike the other perilipins, is thought to be restricted to the fat droplet. We reassessed its cellular distribution using the fat droplet marker CGI-58 in OP9 and 3T3-L1 adipocyte lines and in brown adipose tissue (BAT). As expected, we found perilipin 1 in the fat droplet-enriched floating fraction from centrifuged adipocyte or BAT homogenates. However, about half of perilipin 1 was suspended in the cytosol/infranate or pelleted with cellular membranes. In these fractionations, most of the fat droplet-associated protein CGI-58 was in the floating fraction. In BAT and OP9 adipocytes about a third of perilipin 1 pellets, compared with a much smaller fraction of CGI-58. Co-imaging perilipin 1 and smooth endoplasmic reticulum (ER) markers reveals both ER and fat droplet associated perilipin 1 in OP9 adipocytes. Consistent with these observations, perilipin 1 overexpressed in COS7 cells mostly fractionates with cellular membranes and imaging shows it on the ER. In 3T3-L1 adipocytes almost half of perilipin 1 floats, half is suspended as infranate and small amounts pellet. Finally, driving rapid fat droplet synthesis in OP9 adipocytes increases the intensity of perilipin 1 on fat droplets, while decreasing non-fat droplet immunolabeling. Confirming the morphological findings, fractionation shows perilipin 1 moving from the pelleted to the floated fractions. In conclusion, this study documents an expanded intracellular distribution for perilipin 1 and its movement from ER to fat droplet during lipid synthesis.
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18
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Abstract
Cellular energy homeostasis is a crucial function of oxidative tissues but becomes altered with obesity, a major health problem that is rising unabated and demands attention. Maintaining cardiac lipid homeostasis relies on complex processes and pathways that require concerted actions between lipid droplets (LDs) and mitochondria to prevent intracellular accumulation of bioactive or toxic lipids while providing an efficient supply of lipid for conversion into ATP. While cardiac mitochondria have been extensively studied, cardiac LDs and their role in heart function have not been fully characterized. The cardiac LD compartment is highly dynamic and individual LD is small, making their study challenging. Here, we describe a simple procedure to isolate cardiac LDs that provide sufficient amounts of highly enriched material to allow subsequent protein and lipid biochemical characterization. We also present a detailed protocol to image cardiac LDs by conventional transmission electronic microscopy to provide two-dimensional (2D) analyses of cardiac LDs and mitochondria. Finally, we discuss the potential advantages of dual ion beam and electron beam platform (FIB-SEM) technology to study the cardiac LDs and mitochondria by allowing 3D imaging analysis.
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Affiliation(s)
- Hong Wang
- Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland, USA
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