1
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Nirgude S, Tichy ED, Liu Z, Pradieu RD, Byrne M, Gil De Gomez L, Mamou B, Bernt KM, Yang W, MacFarland S, Xie M, Kalish JM. Single-nucleus multiomic analysis of Beckwith-Wiedemann syndrome liver reveals PPARA signaling enrichment and metabolic dysfunction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.599077. [PMID: 38948745 PMCID: PMC11212859 DOI: 10.1101/2024.06.14.599077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Beckwith-Wiedemann Syndrome (BWS) is an epigenetic overgrowth syndrome caused by methylation changes in the human 11p15 chromosomal locus. Patients with BWS exhibit tissue overgrowth, as well as an increased risk of childhood neoplasms in the liver and kidney. To understand the impact of these 11p15 changes, specifically in the liver, we performed single-nucleus RNA sequencing (snRNA-seq) and single-nucleus assay for transposase-accessible chromatin with sequencing (snATAC-seq) to generate paired, cell-type-specific transcriptional and chromatin accessibility profiles of both BWS-liver and nonBWS-liver nontumorous tissue. Our integrated RNA+ATACseq multiomic approach uncovered hepatocyte-specific enrichment and activation of the peroxisome proliferator-activated receptor α (PPARA) - a liver metabolic regulator. To confirm our findings, we utilized a BWS-induced pluripotent stem cell (iPSC) model, where cells were differentiated into hepatocytes. Our data demonstrates the dysregulation of lipid metabolism in BWS-liver, which coincided with observed upregulation of PPARA during hepatocyte differentiation. BWS liver cells exhibited decreased neutral lipids and increased fatty acid β-oxidation, relative to controls. We also observed increased reactive oxygen species (ROS) byproducts in the form of peroxidated lipids in BWS hepatocytes, which coincided with increased oxidative DNA damage. This study proposes a putative mechanism for overgrowth and cancer predisposition in BWS liver due to perturbed metabolism.
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2
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Xiao S, Ma S, Sun B, Pu W, Duan S, Han J, Hong Y, Zhang J, Peng Y, He C, Yi P, Caligiuri MA, Yu J. The tumor-intrinsic role of the m 6A reader YTHDF2 in regulating immune evasion. Sci Immunol 2024; 9:eadl2171. [PMID: 38820140 DOI: 10.1126/sciimmunol.adl2171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 05/09/2024] [Indexed: 06/02/2024]
Abstract
Tumors evade attacks from the immune system through various mechanisms. Here, we identify a component of tumor immune evasion mediated by YTH domain-containing family protein 2 (YTHDF2), a reader protein that usually destabilizes m6A-modified mRNA. Loss of tumoral YTHDF2 inhibits tumor growth and prolongs survival in immunocompetent tumor models. Mechanistically, tumoral YTHDF2 deficiency promotes the recruitment of macrophages via CX3CL1 and enhances mitochondrial respiration of CD8+ T cells by impairing tumor glycolysis metabolism. Tumoral YTHDF2 deficiency promotes inflammatory macrophage polarization and antigen presentation in the presence of IFN-γ. In addition, IFN-γ induces autophagic degradation of tumoral YTHDF2, thereby sensitizing tumor cells to CD8+ T cell-mediated cytotoxicity. Last, we identified a small molecule compound that preferentially induces YTHDF2 degradation, which shows a potent antitumor effect alone but a better effect when combined with anti-PD-L1 or anti-PD-1 antibodies. Collectively, YTHDF2 appears to be a tumor-intrinsic regulator that orchestrates immune evasion, representing a promising target for enhancing cancer immunotherapy.
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Affiliation(s)
- Sai Xiao
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Hematologic Malignancies Research Institute, City of Hope National Medical Center, Los Angeles, CA 91010, USA
| | - Shoubao Ma
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Hematologic Malignancies Research Institute, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Comprehensive Cancer Center, City of Hope, Los Angeles, CA 91010, USA
| | - Baofa Sun
- State Key Laboratory of Medicinal Chemical Biology, Frontiers Science Center for Cell Responses, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Wenchen Pu
- Laboratory of Molecular Oncology, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Chengdu, China
| | - Songqi Duan
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan 625014, China
| | - Jingjing Han
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Hematologic Malignancies Research Institute, City of Hope National Medical Center, Los Angeles, CA 91010, USA
| | - Yaqun Hong
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Hematologic Malignancies Research Institute, City of Hope National Medical Center, Los Angeles, CA 91010, USA
| | - Jianying Zhang
- Department of Computational and Quantitative Medicine, City of Hope National Medical Center, Los Angeles, CA 91010, USA
| | - Yong Peng
- Laboratory of Molecular Oncology, Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Chengdu, China
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637, USA
| | - Ping Yi
- Third Affiliated Hospital of Chongqing Medical University, Chongqing 401120, China
| | - Michael A Caligiuri
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Hematologic Malignancies Research Institute, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Comprehensive Cancer Center, City of Hope, Los Angeles, CA 91010, USA
| | - Jianhua Yu
- Department of Hematology and Hematopoietic Cell Transplantation, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Hematologic Malignancies Research Institute, City of Hope National Medical Center, Los Angeles, CA 91010, USA
- Comprehensive Cancer Center, City of Hope, Los Angeles, CA 91010, USA
- Department of Immuno-Oncology, Beckman Research Institute, City of Hope, Los Angeles, CA 91010, USA
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3
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Michel L, Durand P, Chevalier A. A Naphthalimide Based "Turn-ON" Probe for Wash-Free Imaging of Lipid-Droplet in Living Cells With an Excellent Selectivity. Chembiochem 2024:e202400270. [PMID: 38683177 DOI: 10.1002/cbic.202400270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/17/2024] [Accepted: 04/29/2024] [Indexed: 05/01/2024]
Abstract
The impacts of dimethylation of 4-Amino-1,8-Naphthalimide (ANI) on its photophysical properties are reported. The resulting 4-DiMe-ANI displays completely different fluorescence properties, conferring it ability to selectively label lipid droplets in living cells. A comprehensive photophysical study revealed that this selectivity arises from an Internal Charge Transfer favored in lipophilic media to the detriment of a non-emissive TICT in more polar media. This results in a very high "LDs/Cytosol" signal ratio, enabling LDs to be imaged with an excellent signal-to-noise ratio, and positioning its performance above that of the BODIPY 493/503 commonly used to image LDs.
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Affiliation(s)
- Laurane Michel
- Université Paris-Saclay, CNRS, UPR 2301, Institut de Chimie des Substances Naturelles, Dpt Chemobiology, 91198, Gif-sur-Yvette, France
| | - Philippe Durand
- Université Paris-Saclay, CNRS, UPR 2301, Institut de Chimie des Substances Naturelles, Dpt Chemobiology, 91198, Gif-sur-Yvette, France
| | - Arnaud Chevalier
- Université Paris-Saclay, CNRS, UPR 2301, Institut de Chimie des Substances Naturelles, Dpt Chemobiology, 91198, Gif-sur-Yvette, France
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4
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Min H, Yang YY, Yang Y. Cold induces brain region-selective neuronal activity-dependent lipid metabolism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.15.589506. [PMID: 38659859 PMCID: PMC11042364 DOI: 10.1101/2024.04.15.589506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Previous studies have been focused on lipid metabolism in peripheral tissues such as adipose tissues, while little or nothing is known about that in the brain. It is well recognized that cold acclimations enhance adipocyte functions, including white adipose tissue (WAT) lipid lipolysis and beiging, and brown adipose tissue (BAT) thermogenesis in mammals. However, it remains unclear whether and how the genes responsible for lipid metabolism in the brain are also under the control of cold acclimations. Here, we show that cold exposure predominantly increases the expressions of the genes encoding lipid lipolysis in the paraventricular nucleus of the hypothalamus (PVH). Mechanistically, we find that inactivation of neurons in the PVH blunts the cold-induced lipid peroxidation and lipolysis. Together, these findings indicate that lipid metabolism in the PVH is cold sensitive, potentially participating in cold regulations of energy metabolism.
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Affiliation(s)
- Hyeonyoung Min
- Department of Medicine Division of Endocrinology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | | | - Yunlei Yang
- Department of Medicine Division of Endocrinology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Einstein-Mount Sinai Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- The Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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5
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Du J, Zhao L, Kang Q, He Y, Bi Y. An optimized method for Oil Red O staining with the salicylic acid ethanol solution. Adipocyte 2023; 12:2179334. [PMID: 36779587 PMCID: PMC9980477 DOI: 10.1080/21623945.2023.2179334] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Oil Red O (ORO) staining is a commonly used experimental technique to detect lipid content in cells or tissues. Freshly prepared ORO in 60% isopropanol is the most widely used method at present. However, isopropanol is volatile and harmful to the human body. It will also affect the interpretation of the results due to the formation of crystals and non-specific diffuse staining. In this paper, by screening and validation, we report a salicylic acid ethanol solution (containing 50% ethanol, 5%-10% salicylic acid) for the preparation of ORO solution, which has a better staining effect on lipid staining in cells and tissues, with a clean background and short dyeing time. What's more, this ORO solution is non-toxic, convenient to prepare, and can be stored for a long time. Therefore, it is reliable, easy to operate, and can be widely popularized and applied in laboratories.
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Affiliation(s)
- Junbao Du
- Stem Cell Biology and Therapy Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China.,National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, P.R. China
| | - Li Zhao
- Stem Cell Biology and Therapy Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China.,National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, P.R. China
| | - Quan Kang
- Stem Cell Biology and Therapy Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China
| | - Yun He
- Stem Cell Biology and Therapy Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China.,National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, P.R. China
| | - Yang Bi
- Stem Cell Biology and Therapy Laboratory, Children's Hospital of Chongqing Medical University, Chongqing, P.R. China.,National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, P.R. China
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6
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Sharma CP, Vyas A, Pandey P, Gupta S, Vats RP, Jaiswal SP, Bhatt MLB, Sachdeva M, Goel A. A new class of teraryl-based AIEgen for highly selective imaging of intracellular lipid droplets and its detection in advanced-stage human cervical cancer tissues. J Mater Chem B 2023; 11:9922-9932. [PMID: 37840367 DOI: 10.1039/d3tb01764h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
Lipid droplets (LDs) have drawn much attention in recent years. They serve as the energy reservoir of cells and also play an important role in numerous physiological processes. Furthermore, LDs are found to be associated with several pathological conditions, including cancer and diabetes mellitus. Herein, we report a new class of teraryl-based donor-acceptor-appended aggregation-induced emission luminogen (AIEgen), 6a, for selective staining of intracellular LDs in in vitro live 3T3-L1 preadipocytes and the HeLa cancer cell line. In addition, AIEgen 6a was found to be capable of staining and quantifying the LD accumulation in the tissue sections of advanced-stage human cervical cancer patients. Unlike commercial LD staining dyes Nile Red, BODIPY and LipidTOX, AIEgen 6a showed a high Stokes shift (195 nm), a good fluorescence lifetime decay of 12.7 ns, and LD staining persisting for nearly two weeks.
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Affiliation(s)
- Chandra Prakash Sharma
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
| | - Akanksha Vyas
- Division of Endocrinology CSIR-Central Drug Research Institute, Lucknow, 226031, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Priyanka Pandey
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
| | - Shashwat Gupta
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Ravi Prakash Vats
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Sakshi Priya Jaiswal
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
| | | | - Monika Sachdeva
- Division of Endocrinology CSIR-Central Drug Research Institute, Lucknow, 226031, India
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
| | - Atul Goel
- Fluorescent Chemistry Lab, Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, 226031, India.
- Academy of Scientific and Innovative Research, Ghaziabad 201002, India
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7
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Cardone N, Taglietti V, Baratto S, Kefi K, Periou B, Gitiaux C, Barnerias C, Lafuste P, Pharm FL, Pharm JN, Panicucci C, Desguerre I, Bruno C, Authier FJ, Fiorillo C, Relaix F, Malfatti E. Myopathologic trajectory in Duchenne muscular dystrophy (DMD) reveals lack of regeneration due to senescence in satellite cells. Acta Neuropathol Commun 2023; 11:167. [PMID: 37858263 PMCID: PMC10585739 DOI: 10.1186/s40478-023-01657-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 09/19/2023] [Indexed: 10/21/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating X-linked muscular disease, caused by mutations in the DMD gene encoding Dystrophin and affecting 1:5000 boys worldwide. Lack of Dystrophin leads to progressive muscle wasting and degeneration resulting in cardiorespiratory failure. Despite the absence of a definitive cure, innovative therapeutic avenues are emerging. Myopathologic studies are important to further understand the biological mechanisms of the disease and to identify histopathologic benchmarks for clinical evaluations. We conducted a myopathologic analysis on twenty-four muscle biopsies from DMD patients, with particular emphasis on regeneration, fibro-adipogenic progenitors and muscle stem cells behavior. We describe an increase in content of fibro-adipogenic progenitors, central orchestrators of fibrotic progression and lipid deposition, concurrently with a decline in muscle regenerative capacity. This regenerative impairment strongly correlates with compromised activation and expansion of muscle stem cells. Furthermore, our study uncovers an early acquisition of a senescence phenotype by DMD-afflicted muscle stem cells. Here we describe the myopathologic trajectory intrinsic to DMD and establish muscle stem cell senescence as a pivotal readout for future therapeutic interventions.
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Affiliation(s)
| | | | - Serena Baratto
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Kaouthar Kefi
- Univ Paris Est Creteil, INSERM, IMRB, 94010, Creteil, France
| | - Baptiste Periou
- Univ Paris Est Creteil, INSERM, IMRB, 94010, Creteil, France
- APHP, Filnemus, EuroNMD, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor Hospital, Paris, France
| | - Ciryl Gitiaux
- Neurophysiologie clinique pédiatrique, Centre de référence des maladies neuromusculaires Hôpital universitaire Necker-Enfants Malades-Paris, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor Hospital, Université Paris Est, U955 INSERM, IMRB, APHP, Creteil, France
- Reference Center for Neuromuscular Disorders, Filnemus, EuroNMD, Assistance Publique-Hôpitaux de Paris (APHP) Necker Enfants Malades Hospital, Paris, France
| | - Christine Barnerias
- Reference Center for Neuromuscular Disorders, Filnemus, EuroNMD, Assistance Publique-Hôpitaux de Paris (APHP) Necker Enfants Malades Hospital, Paris, France
| | - Peggy Lafuste
- Univ Paris Est Creteil, INSERM, IMRB, 94010, Creteil, France
| | - France Leturcq Pharm
- Service de Médecine Génomique, Maladies de Système et d'Organe - Fédération de Génétique et de Médecine Génomique, DMU BioPhyGen, APHP Centre-Université Paris Cité - Hôpital Cochin, Paris, France
| | - Juliette Nectoux Pharm
- Service de Médecine Génomique, Maladies de Système et d'Organe - Fédération de Génétique et de Médecine Génomique, DMU BioPhyGen, APHP Centre-Université Paris Cité - Hôpital Cochin, Paris, France
| | - Chiara Panicucci
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Isabelle Desguerre
- Reference Center for Neuromuscular Disorders, Filnemus, EuroNMD, Assistance Publique-Hôpitaux de Paris (APHP) Necker Enfants Malades Hospital, Paris, France
| | - Claudio Bruno
- Centre of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health-DINOGMI, University of Genova, Genoa, Italy
| | - François-Jerome Authier
- Univ Paris Est Creteil, INSERM, IMRB, 94010, Creteil, France
- APHP, Filnemus, EuroNMD, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor Hospital, Paris, France
| | - Chiara Fiorillo
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health-DINOGMI, University of Genova, Genoa, Italy
- Child Neuropsychiatry, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Frederic Relaix
- Univ Paris Est Creteil, INSERM, IMRB, 94010, Creteil, France.
| | - Edoardo Malfatti
- Univ Paris Est Creteil, INSERM, IMRB, 94010, Creteil, France.
- APHP, Filnemus, EuroNMD, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor Hospital, Paris, France.
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8
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Arumugam MK, Perumal SK, Rasineni K, Donohue TM, Osna NA, Kharbanda KK. Lipidomic Analysis of Liver Lipid Droplets after Chronic Alcohol Consumption with and without Betaine Supplementation. BIOLOGY 2023; 12:462. [PMID: 36979154 PMCID: PMC10045066 DOI: 10.3390/biology12030462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 03/04/2023] [Accepted: 03/08/2023] [Indexed: 03/19/2023]
Abstract
The earliest manifestation of alcohol-associated liver disease is hepatic steatosis, which is characterized by fat accumulation in specialized organelles called lipid droplets (LDs). Our previous studies reported that alcohol consumption elevates the numbers and sizes of LDs in hepatocytes, which is attenuated by simultaneous treatment with the methyl group donor, betaine. Here, we examined changes in the hepatic lipidome with respect to LD size and dynamics in male Wistar rats fed for 6 weeks with control or ethanol-containing liquid diets that were supplemented with or without 10 mg betaine/mL. At the time of sacrifice, three hepatic LD fractions, LD1 (large droplets), LD2 (medium-sized droplets), and LD3 (small droplets) were isolated from each rat. Untargeted lipidomic analyses revealed that each LD fraction of ethanol-fed rats had higher phospholipids, cholesteryl esters, diacylglycerols, ceramides, and hexosylceramides compared with the corresponding fractions of pair-fed controls. Interestingly, the ratio of phosphatidylcholine to phosphatidylethanolamine (the two most abundant phospholipids on the LD surface) was lower in LD1 fraction compared with LD3 fraction, irrespective of treatment; however, this ratio was significantly lower in ethanol LD fractions compared with their respective control fractions. Betaine supplementation significantly attenuated the ethanol-induced lipidomic changes. These were mainly associated with the regulation of LD surface phospholipids, ceramides, and glycerolipid metabolism in different-sized LD fractions. In conclusion, our results show that ethanol-induced changes in the hepatic LD lipidome likely stabilizes larger-sized LDs during steatosis development. Furthermore, betaine supplementation could effectively reduce the size and dynamics of LDs to attenuate alcohol-associated hepatic steatosis.
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Affiliation(s)
- Madan Kumar Arumugam
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Center for Molecular and Nanomedical Sciences, Sathyabama Institute of Science and Technology, Chennai 600119, India
| | - Sathish Kumar Perumal
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Karuna Rasineni
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Terrence M. Donohue
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Natalia A. Osna
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kusum K. Kharbanda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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9
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Amarasinghe I, Phillips W, Hill AF, Cheng L, Helbig KJ, Willms E, Monson EA. Cellular communication through extracellular vesicles and lipid droplets. JOURNAL OF EXTRACELLULAR BIOLOGY 2023; 2:e77. [PMID: 38938415 PMCID: PMC11080893 DOI: 10.1002/jex2.77] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/06/2023] [Accepted: 02/15/2023] [Indexed: 06/29/2024]
Abstract
Cellular communication is essential for effective coordination of biological processes. One major form of intercellular communication occurs via the release of extracellular vesicles (EVs). These vesicles mediate intercellular communication through the transfer of their cargo and are actively explored for their role in various diseases and their potential therapeutic and diagnostic applications. Conversely, lipid droplets (LDs) are vesicles that transfer cargo within cells. Lipid droplets play roles in various diseases and evidence for their ability to transfer cargo between cells is emerging. To date, there has been little interdisciplinary research looking at the similarities and interactions between these two classes of small lipid vesicles. This review will compare the commonalities and differences between EVs and LDs including their biogenesis and secretion, isolation and characterisation methodologies, composition, and general heterogeneity and discuss challenges and opportunities in both fields.
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Affiliation(s)
- Irumi Amarasinghe
- School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneAustralia
| | - William Phillips
- School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneAustralia
- La Trobe Institute for Molecular SciencesLa Trobe UniversityMelbourneAustralia
| | - Andrew F. Hill
- Institute for Health and SportVictoria UniversityFootscrayVictoriaAustralia
| | - Lesley Cheng
- School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneAustralia
- La Trobe Institute for Molecular SciencesLa Trobe UniversityMelbourneAustralia
| | - Karla J. Helbig
- School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneAustralia
| | - Eduard Willms
- School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneAustralia
- La Trobe Institute for Molecular SciencesLa Trobe UniversityMelbourneAustralia
| | - Ebony A. Monson
- School of Agriculture, Biomedicine and EnvironmentLa Trobe UniversityMelbourneAustralia
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10
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Cui K, Gao X, Wang B, Wu H, Arulsamy K, Dong Y, Xiao Y, Jiang X, Malovichko MV, Li K, Peng Q, Lu YW, Zhu B, Zheng R, Wong S, Cowan DB, Linton M, Srivastava S, Shi J, Chen K, Chen H. Epsin Nanotherapy Regulates Cholesterol Transport to Fortify Atheroma Regression. Circ Res 2023; 132:e22-e42. [PMID: 36444722 PMCID: PMC9822875 DOI: 10.1161/circresaha.122.321723] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 11/14/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Excess cholesterol accumulation in lesional macrophages elicits complex responses in atherosclerosis. Epsins, a family of endocytic adaptors, fuel the progression of atherosclerosis; however, the underlying mechanism and therapeutic potential of targeting Epsins remains unknown. In this study, we determined the role of Epsins in macrophage-mediated metabolic regulation. We then developed an innovative method to therapeutically target macrophage Epsins with specially designed S2P-conjugated lipid nanoparticles, which encapsulate small-interfering RNAs to suppress Epsins. METHODS We used single-cell RNA sequencing with our newly developed algorithm MEBOCOST (Metabolite-mediated Cell Communication Modeling by Single Cell Transcriptome) to study cell-cell communications mediated by metabolites from sender cells and sensor proteins on receiver cells. Biomedical, cellular, and molecular approaches were utilized to investigate the role of macrophage Epsins in regulating lipid metabolism and transport. We performed this study using myeloid-specific Epsin double knockout (LysM-DKO) mice and mice with a genetic reduction of ABCG1 (ATP-binding cassette subfamily G member 1; LysM-DKO-ABCG1fl/+). The nanoparticles targeting lesional macrophages were developed to encapsulate interfering RNAs to treat atherosclerosis. RESULTS We revealed that Epsins regulate lipid metabolism and transport in atherosclerotic macrophages. Inhibiting Epsins by nanotherapy halts inflammation and accelerates atheroma resolution. Harnessing lesional macrophage-specific nanoparticle delivery of Epsin small-interfering RNAs, we showed that silencing of macrophage Epsins diminished atherosclerotic plaque size and promoted plaque regression. Mechanistically, we demonstrated that Epsins bound to CD36 to facilitate lipid uptake by enhancing CD36 endocytosis and recycling. Conversely, Epsins promoted ABCG1 degradation via lysosomes and hampered ABCG1-mediated cholesterol efflux and reverse cholesterol transport. In a LysM-DKO-ABCG1fl/+ mouse model, enhanced cholesterol efflux and reverse transport due to Epsin deficiency was suppressed by the reduction of ABCG1. CONCLUSIONS Our findings suggest that targeting Epsins in lesional macrophages may offer therapeutic benefits for advanced atherosclerosis by reducing CD36-mediated lipid uptake and increasing ABCG1-mediated cholesterol efflux.
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Affiliation(s)
- Kui Cui
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Xinlei Gao
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Beibei Wang
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Hao Wu
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Kulandaisamy Arulsamy
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Yunzhou Dong
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Yuling Xiao
- Center for Nanomedicine and Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Xingya Jiang
- Center for Nanomedicine and Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Marina V. Malovichko
- Division of Environmental Medicine, University of Louisville, Louisville, KY, 40292, USA
| | - Kathryn Li
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Qianman Peng
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Yao Wei Lu
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Bo Zhu
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Rongbin Zheng
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Scott Wong
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - Douglas B. Cowan
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
| | - MacRae Linton
- Atherosclerosis Research Unit, Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center; Nashville, TN, 37232, USA
| | - Sanjay Srivastava
- Division of Environmental Medicine, University of Louisville, Louisville, KY, 40292, USA
| | - Jinjun Shi
- Center for Nanomedicine and Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Kaifu Chen
- Department of Cardiology, Boston Children’s Hospital, Harvard Medical School; Boston, MA, 02115, USA
| | - Hong Chen
- Vascular Biology Program, Boston Children’s Hospital and Department of Surgery, Harvard Medical School; Boston, MA, 02115, USA
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11
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Sharma T, Kavita, Mishra BB, Variyar PS. Detection of gamma radiation processed onion during storage using propidium iodide based fluorescence microscopy. Food Chem 2023; 398:133928. [DOI: 10.1016/j.foodchem.2022.133928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/11/2022] [Accepted: 08/09/2022] [Indexed: 11/26/2022]
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12
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Khan D, Ara T, Munjal A, Mishra S, Sundaresan NR. Microscopy-Based Assessment of Fatty Acid Uptake and Lipid Accumulation in Cultured Cells. Curr Protoc 2022; 2:e626. [PMID: 36571583 DOI: 10.1002/cpz1.626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The heart relies predominantly on the use of fatty acids to derive energy. Metabolic disorders such as obesity, insulin resistance, and diabetes pose a major risk factor for the development of heart failure. Dysregulation of lipid metabolism observed in these diseases manifests as cardiac lipotoxicity, and is associated with cardiac dysfunction. The alarming rise in the incidence of these metabolic disorders warrants the need for tools to investigate the underlying molecular mechanisms. In this article, we describe a confocal microscopy-based approach to monitor fatty acid uptake and lipid accumulation in vitro, in neonatal murine cardiomyocytes and H9c2 cells. The protocol for assessment of fatty acid uptake relies on the use of BODIPY FL C 12™ to study the kinetics of fatty acid uptake via real-time imaging of fatty acid uptake in live cells. Importantly, it circumvents the need for radioactive labeling of fatty acids to evaluate their uptake. Similarly, the protocol for assessment of lipid accumulation relies on the use of BODIPY™ 493/503 to stain the cytosolic neutral lipid population in fixed cells. We couple these confocal microscopy-based approaches with fluorescence intensity analysis using FIJI to quantify fatty acid uptake and lipid accumulation in vitro. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Assessment of fatty acid uptake Basic Protocol 2: Assessment of lipid accumulation.
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Affiliation(s)
- Danish Khan
- Cardiovascular and Muscle Research Laboratory, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Tarannum Ara
- Cardiovascular and Muscle Research Laboratory, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Aastha Munjal
- Cardiovascular and Muscle Research Laboratory, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Sneha Mishra
- Cardiovascular and Muscle Research Laboratory, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
| | - Nagalingam Ravi Sundaresan
- Cardiovascular and Muscle Research Laboratory, Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru, India
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13
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Emerald BS, Al Jailani MA, Ibrahim MF, Kumar CA, Allouh MZ. Cellular and Molecular Variations in Male and Female Murine Skeletal Muscle after Long-Term Feeding with a High-Fat Diet. Int J Mol Sci 2022; 23:ijms23179547. [PMID: 36076943 PMCID: PMC9455932 DOI: 10.3390/ijms23179547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 11/16/2022] Open
Abstract
Current information regarding the effects of a high-fat diet (HFD) on skeletal muscle is contradictory. This study aimed to investigate the effects of a long-term HFD on skeletal muscle in male and female mice at the morphological, cellular, and molecular levels. Adult mice of the C57BL/6 strain were fed standard chow or an HFD for 20 weeks. The tibialis anterior muscles were dissected, weighed, and processed for cellular and molecular analyses. Immunocytochemical and morphometric techniques were applied to quantify fiber size, satellite cells (SCs), and myonuclei. Additionally, PCR array and RT-qPCR tests were performed to determine the expression levels of key muscle genes. Muscles from HFD mice showed decreases in weight, SCs, and myonuclei, consistent with the atrophic phenotype. This atrophy was associated with a decrease in the percentage of oxidative fibers within the muscle. These findings were further confirmed by molecular analyses that showed significant reductions in the expression of Pax7, Myh1, and Myh2 genes and increased Mstn gene expression. Male and female mice showed similar trends in response to HFD-induced obesity. These findings indicate that the long-term effects of obesity on skeletal muscle resemble those of age-related sarcopenia.
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14
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Schwehr BJ, Hartnell D, Massi M, Hackett MJ. Luminescent Metal Complexes as Emerging Tools for Lipid Imaging. Top Curr Chem (Cham) 2022; 380:46. [PMID: 35976575 PMCID: PMC9385838 DOI: 10.1007/s41061-022-00400-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 06/20/2022] [Indexed: 12/01/2022]
Abstract
Fluorescence microscopy is a key tool in the biological sciences, which finds use as a routine laboratory technique (e.g., epifluorescence microscope) or more advanced confocal, two-photon, and super-resolution applications. Through continued developments in microscopy, and other analytical methods, the importance of lipids as constituents of subcellular organelles, signalling or regulating molecules continues to emerge. The increasing recognition of the importance of lipids to fundamental cell biology (in health and disease) has prompted the development of protocols and techniques to image the distribution of lipids in cells and tissues. A diverse suite of spectroscopic and microscopy tools are continuously being developed and explored to add to the "toolbox" to study lipid biology. A relatively recent breakthrough in this field has been the development and subsequent application of metal-based luminescent complexes for imaging lipids in biological systems. These metal-based compounds appear to offer advantages with respect to their tunability of the photophysical properties, in addition to capabilities centred around selectively targeting specific lipid structures or classes of lipids. The presence of the metal centre also opens the path to alternative imaging modalities that might not be applicable to traditional organic fluorophores. This review examines the current progress and developments in metal-based luminescent complexes to study lipids, in addition to exploring potential new avenues and challenges for the field to take.
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Affiliation(s)
- Bradley J Schwehr
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia
| | - David Hartnell
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia.,Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6845, Australia
| | - Massimiliano Massi
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia.
| | - Mark J Hackett
- School of Molecular and Life Sciences, Curtin University, Perth, WA, 6845, Australia. .,Curtin Health Innovation Research Institute, Curtin University, Perth, WA, 6845, Australia.
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15
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Kähärä I, Durandin N, Ilina P, Efimov A, Laaksonen T, Vuorimaa-Laukkanen E, Lisitsyna E. Phototoxicity of BODIPY in long-term imaging can be reduced by intramolecular motion. PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES : OFFICIAL JOURNAL OF THE EUROPEAN PHOTOCHEMISTRY ASSOCIATION AND THE EUROPEAN SOCIETY FOR PHOTOBIOLOGY 2022; 21:1677-1687. [PMID: 35796875 DOI: 10.1007/s43630-022-00250-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 05/23/2022] [Indexed: 11/24/2022]
Abstract
For long-term live-cell fluorescence imaging and biosensing, it is crucial to work with a dye that has high fluorescence quantum yield and photostability without being detrimental to the cells. In this paper, we demonstrate that neutral boron-dipyrromethene (BODIPY)-based molecular rotors have great properties for high-light-dosage demanding live-cell fluorescence imaging applications that require repetitive illuminations. In molecular rotors, an intramolecular rotation (IMR) allows an alternative route for the decay of the singlet excited state (S1) via the formation of an intramolecular charge transfer state (CT). The occurrence of IMR reduces the probability of the formation of a triplet state (T1) which could further react with molecular oxygen (3O2) to form cytotoxic reactive oxygen species, e.g., singlet oxygen (1O2). We demonstrate that the oxygen-related nature of the phototoxicity for BODIPY derivatives can be significantly reduced if a neutral molecular rotor is used as a probe. The studied neutral molecular rotor probe shows remarkably lower phototoxicity when compared with both the non-rotating BODIPY derivative and the cationic BODIPY-based molecular rotor in different light dosages and dye concentrations. It is also evident that the charge and localization of the fluorescent probe are as significant as the IMR in terms of the phototoxicity in a long-term live-cell imaging.
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Affiliation(s)
- Iida Kähärä
- Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland.
| | - Nikita Durandin
- Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland
| | - Polina Ilina
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Alexander Efimov
- Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland
| | - Timo Laaksonen
- Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, P.O. Box 56, 00014, Helsinki, Finland
| | - Elina Vuorimaa-Laukkanen
- Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland
| | - Ekaterina Lisitsyna
- Chemistry and Advanced Materials, Unit of Materials Science and Environmental Engineering, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, 33014, Tampere, Finland.
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16
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Dong Y, Yu M, Wu Y, Xia T, Wang L, Song K, Zhang C, Lu K, Rahimnejad S. Hydroxytyrosol Promotes the Mitochondrial Function through Activating Mitophagy. Antioxidants (Basel) 2022; 11:893. [PMID: 35624756 PMCID: PMC9138034 DOI: 10.3390/antiox11050893] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/26/2022] [Accepted: 04/28/2022] [Indexed: 02/06/2023] Open
Abstract
Emerging evidence suggests that mitochondrial dysfunction mediates the pathogenesis for non-alcoholic fatty liver disease (NAFLD). Hydroxytyrosol (HT) is a key component of extra virgin olive oil which can exert beneficial effects on NAFLD through modulating mitochondria. However, the mechanism of the impacts of HT still remains elusive. Thus, an in vivo and a series of in vitro experiments were carried out to examine the impacts of hydroxytyrosol (HT) on lipid metabolism and mitochondrial function in fish. For the in vivo experiment, two diets were produced to contain 10% and 16% fat as normal-fat and high-fat diets (NFD and HFD) and two additional diets were prepared by supplementing 200 mg/kg of HT to the NFD and HFD. The test diets were fed to triplicate groups of spotted seabass (Lateolabrax maculatus) juveniles for 8 weeks. The results showed that feeding HFD leads to increased fat deposition in the liver and induces oxidative stress, both of which were ameliorated by HT application. Furthermore, transmission electron microscopy revealed that HFD destroyed mitochondrial cristae and matrix and induced severe hydropic phenotype, while HT administration relieved these alterations. The results of in vitro studies using zebrafish liver cell line (ZFL) showed that HT promotes mitochondrial function and activates PINK1-mediated mitophagy. These beneficial effects of HT disappeared when the cells were treated with cyclosporin A (Csa) as a mitophagy inhibitor. Moreover, the PINK1-mediated mitophagy activation by HT was blocked when compound C (CC) was used as an AMPK inhibitor. In conclusion, our findings demonstrated that HT alleviates fat accumulation, oxidative stress and mitochondrial dysfunction, and its effects are deemed to be mediated via activating mitophagy through the AMPK/PINK1 pathway.
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Affiliation(s)
- Yanzou Dong
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
| | - Manhan Yu
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
- Key Laboratory of Swine Nutrition and Feed Science of Fujian Province, Fujian Aonong Biological Science and Technology Group Co., Ltd., Zhangzhou 363000, China;
| | - Youlin Wu
- Key Laboratory of Swine Nutrition and Feed Science of Fujian Province, Fujian Aonong Biological Science and Technology Group Co., Ltd., Zhangzhou 363000, China;
| | - Tian Xia
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
| | - Ling Wang
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
| | - Kai Song
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
| | - Chunxiao Zhang
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
| | - Kangle Lu
- Key Laboratory for Feed Quality Testing and Safety, Fisheries College, Jimei University, Xiamen 361021, China; (Y.D.); (M.Y.); (T.X.); (L.W.); (K.S.); (C.Z.)
| | - Samad Rahimnejad
- South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, Zatisi 728/II, 389 25 Vodnany, Czech Republic;
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17
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Taglietti V, Kefi K, Bronisz-Budzyńska I, Mirciloglu B, Rodrigues M, Cardone N, Coulpier F, Periou B, Gentil C, Goddard M, Authier FJ, Pietri-Rouxel F, Malfatti E, Lafuste P, Tiret L, Relaix F. Duchenne muscular dystrophy trajectory in R-DMDdel52 preclinical rat model identifies COMP as biomarker of fibrosis. Acta Neuropathol Commun 2022; 10:60. [PMID: 35468843 PMCID: PMC9036715 DOI: 10.1186/s40478-022-01355-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/25/2022] [Indexed: 11/10/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal muscle-wasting disorder caused by mutations in the Dystrophin gene and for which there is currently no cure. To bridge the gap between preclinical and therapeutic evaluation studies, we have generated a rat model for DMD that carries an exon 52 deletion (R-DMDdel52) causing a complete lack of dystrophin protein. Here we show that R-DMDdel52 animals recapitulated human DMD pathophysiological trajectory more faithfully than the mdx mouse model. We report that R-DMDdel52 rats displayed progressive and severe skeletal muscle loss associated with fibrotic deposition, fat infiltration and fibre type switch. Early fibrosis was also apparent in the cardiac muscle. These histological modifications led to severe muscle, respiratory and cardiac functional impairments leading to premature death around 1 year. Moreover, DMD muscle exhibited systemic inflammation with a mixed M1/M2 phenotype. A comparative single cell RNAseq analysis of the diaphragm muscle was performed, revealing cellular populations alteration and molecular modifications in all muscle cell types. We show that DMD fibroadipogenic progenitors produced elevated levels of cartilage oligomeric matrix protein, a glycoprotein responsible for modulating homeostasis of extracellular matrix, and whose increased concentration correlated with muscle fibrosis both in R-DMDdel52 rats and human patients. Fibrosis is a component of tissue remodelling impacting the whole musculature of DMD patients, at the tissue level but most importantly at the functional level. We therefore propose that this specific biomarker can optimize the prognostic monitoring of functional improvement of patients included in clinical trials.
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18
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Antony R, Aby K, Gao H, Eichholz M, Srinivasan R, Li Y. UCHL1 Regulates Lipid and Perilipin 2 Level in Skeletal Muscle. Front Physiol 2022; 13:855193. [PMID: 35464088 PMCID: PMC9021748 DOI: 10.3389/fphys.2022.855193] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/21/2022] [Indexed: 11/14/2022] Open
Abstract
Ubiquitin C-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme that was originally found in neurons. We found that UCHL1 is highly expressed in slow oxidative skeletal muscles, but its functions remain to be fully understood. In this study, we observed that UCHL1 protein levels in skeletal muscle and C2C12 myotubes were downregulated by fasting or glucose starvation respectively. Skeletal muscle selective knockout (smKO) of UCHL1 resulted in a significant reduction of lipid content in skeletal muscle and improved glucose tolerance. UCHL1 smKO did not significantly change the levels of key proteins involved in oxidative metabolism such as SDHA, Akt, or PDH. Interestingly, while the levels of the major lipases and lipid transporters were unchanged, perilipin 2 was significantly downregulated in UCHL1 smKO muscle. Consistently, in C2C12 myotubes, UCHL1 siRNA knockdown also reduced perilipin 2 protein level. This data suggests that UCHL1 may stabilize perilipin 2 and thus lipid storage in skeletal muscle.
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Affiliation(s)
| | | | | | | | | | - Yifan Li
- Division of Basic Biomedical Sciences, University of South Dakota Sanford School of Medicine, Vermillion, SD, United States
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19
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Drosophila Lysophospholipase Gene swiss cheese Is Required for Survival and Reproduction. INSECTS 2021; 13:insects13010014. [PMID: 35055857 PMCID: PMC8781823 DOI: 10.3390/insects13010014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/15/2021] [Accepted: 12/17/2021] [Indexed: 12/28/2022]
Abstract
Simple Summary Biological evolution implies fitness of newly evolved organisms that have inherent adaptive traits because of mutations in genes. However, most mutations are detrimental, and they spoil the organism’s life, its survival and its ability to leave progeny. Some genes are extremely vital for an organism, and therefore, they tend to save their structure and do not mutate or do it very composedly. That is the case of the gene encoding PNPLA6 lysophospholipase domain that evolved in bacteria, and evolution obliged it to save its function in higher animals. In mammals, complete dysfunction of such a gene is lethal because of its high importance in placenta for early embryo development. Why is it conserved in other species, for instance insects, that have no placenta? Here we studied the role of the PNPLA6-encoding gene named swiss cheese in Drosophila melanogaster fitness. We have found that its dysfunction results in premature death of specimens and their inability to leave enough progeny. Thus, we provide the first evidence for significance of the gene that encodes the lysophospholipase enzyme in fitness of insects. Abstract Drosophila melanogaster is one of the most famous insects in biological research. It is widely used to analyse functions of different genes. The phosphatidylcholine lysophospholipase gene swiss cheese was initially shown to be important in the fruit fly nervous system. However, the role of this gene in non-nervous cell types has not been elucidated yet, and the evolutional explanation for the conservation of its function remains elusive. In this study, we analyse expression pattern and some aspects of the role of the swiss cheese gene in the fitness of Drosophila melanogaster. We describe the spatiotemporal expression of swiss cheese throughout the fly development and analyse the survival and productivity of swiss cheese mutants. We found swiss cheese to be expressed in salivary glands, midgut, Malpighian tubes, adipocytes, and male reproductive system. Dysfunction of swiss cheese results in severe pupae and imago lethality and decline of fertility, which is impressive in males. The latter is accompanied with abnormalities of male locomotor activity and courtship behaviour, accumulation of lipid droplets in testis cyst cells and decrease in spermatozoa motility. These results suggest that normal swiss cheese is important for Drosophila melanogaster fitness due to its necessity for both specimen survival and their reproductive success.
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20
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Reza AHMM, Zhou Y, Qin J, Tang Y. Aggregation-induced emission luminogens for lipid droplet imaging. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 184:101-144. [PMID: 34749970 DOI: 10.1016/bs.pmbts.2021.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lipid droplets (LDs) are evolutionarily conserved organelles involved in energy homeostasis and versatile intracellular processes in different cell types. Their importance is ubiquitous, ranges from utilization as the biofunctional components to third-generation biofuel production from microalgae, while morphology and functional perturbations could also relate to the multiple diseases in higher mammals. Biosynthesis of lipids can be triggered by multiple factors related to organismal physiology and the surrounding environment. An early prediction of this might help take necessary actions toward desired outcomes. In vivo visualization of LDs can give molecular insight into regulatory mechanisms and the underlying connections with other cellular structures. Traditional bioprobes for LDs detection often suffer from different dye-specific limitations such as aggregation-caused quenching and self-decomposition phenomena that hinder the research advancement. The emergence of lipid-specific nanoprobes with aggregation-induced emission (AIE) attributes in recent years is promising in remunerative characteristics with defined bioimaging properties. By utilizing the easy synthetic techniques and exploiting the unique physical features of these molecules, highly selective, stable, biocompatible and facile fluorescent probes could be fabricated for lipid detection. This chapter will provide up-to-date insight into the recent advances in lipid-specific AIE-based probes to enhance the opportunities for basic research related to the distinct roles of LDs in living organisms.
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Affiliation(s)
- A H M Mohsinul Reza
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia; Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Yabin Zhou
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | - Jianguang Qin
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia.
| | - Youhong Tang
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia; Institute for NanoScale Science and Technology, College of Science and Engineering, Flinders University, Adelaide, SA, Australia.
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21
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Taatjes DJ, Roth J. In focus in HCB. Histochem Cell Biol 2021; 154:347-354. [PMID: 32984928 DOI: 10.1007/s00418-020-01921-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Douglas J Taatjes
- Department of Pathology and Laboratory Medicine, Larner College of Medicine, University of Vermont, Burlington, VT, 05405, USA.
| | - Jürgen Roth
- University of Zurich, 8091, Zurich, Switzerland
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22
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Singh A, Sen P. Lipid droplet: A functionally active organelle in monocyte to macrophage differentiation and its inflammatory properties. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158981. [PMID: 34119681 DOI: 10.1016/j.bbalip.2021.158981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 05/06/2021] [Accepted: 05/20/2021] [Indexed: 12/28/2022]
Abstract
Lipid droplets (LDs) perform several important functions like inflammatory responses, membrane trafficking, acts as secondary messengers, etc. rather than simply working as an energy reservoir. LDs have been implicated as a controlling factor in the progression of atherosclerosis followed by foam cell formation that derives from macrophages during the differentiation process. However, the role of LDs in monocyte differentiation or its further immunological function is still an area that mandates in-depth investigation. We report that LD dynamics is important for differentiation of monocytes and is absolutely required for sustained and prolonged functional activity of differentiated macrophages. In THP-1 cell line model system, we elucidated that increase in total LD content in monocyte by external lipid supplements, can induce monocyte differentiation independent of classical stimuli, PMA. Differential expression of PLIN2 and ATGL during the event, together with abrogation of de novo lipogenesis further confirmed the fact. Besides, an increase in LD content by free fatty acid supplement was able to exert a synergistic effect with PMA on differentiation and phagocytic activity compared to when they are used alone. Additionally, we have shown Rab5a to play a vital role in LDs biosynthesis/maturation in monocytes and thereby directly affecting differentiation of monocytes into macrophages via AKT pathway. Thus our study reveals the multi-faceted function of LDs during the process of monocyte to macrophage differentiation and thereby helping to maintain the functional activity.
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Affiliation(s)
- Arpana Singh
- School of Biological Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Prosenjit Sen
- School of Biological Sciences, Indian Association for the Cultivation of Science, Kolkata 700032, India.
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23
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Liu X, Hartman CL, Li L, Albert CJ, Si F, Gao A, Huang L, Zhao Y, Lin W, Hsueh EC, Shen L, Shao Q, Hoft DF, Ford DA, Peng G. Reprogramming lipid metabolism prevents effector T cell senescence and enhances tumor immunotherapy. Sci Transl Med 2021; 13:13/587/eaaz6314. [PMID: 33790024 DOI: 10.1126/scitranslmed.aaz6314] [Citation(s) in RCA: 110] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 08/27/2020] [Accepted: 03/03/2021] [Indexed: 01/14/2023]
Abstract
The functional state of T cells is a key determinant for effective antitumor immunity and immunotherapy. Cellular metabolism, including lipid metabolism, controls T cell differentiation, survival, and effector functions. Here, we report that development of T cell senescence driven by both malignant tumor cells and regulatory T cells is a general feature in cancers. Senescent T cells have active glucose metabolism but exhibit unbalanced lipid metabolism. This unbalanced lipid metabolism results in changes of expression of lipid metabolic enzymes, which, in turn, alters lipid species and accumulation of lipid droplets in T cells. Tumor cells and Treg cells drove elevated expression of group IVA phospholipase A2, which, in turn, was responsible for the altered lipid metabolism and senescence induction observed in T cells. Mitogen-activated protein kinase signaling and signal transducer and activator of transcription signaling coordinately control lipid metabolism and group IVA phospholipase A2 activity in responder T cells during T cell senescence. Inhibition of group IVA phospholipase A2 reprogrammed effector T cell lipid metabolism, prevented T cell senescence in vitro, and enhanced antitumor immunity and immunotherapy efficacy in mouse models of melanoma and breast cancer in vivo. Together, these findings identify mechanistic links between T cell senescence and regulation of lipid metabolism in the tumor microenvironment and provide a new target for tumor immunotherapy.
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Affiliation(s)
- Xia Liu
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Celine L Hartman
- Edward A. Doisy Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Lingyun Li
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Carolyn J Albert
- Edward A. Doisy Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Fusheng Si
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Aiqin Gao
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Lan Huang
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA.,Department of Immunology, Key Laboratory of Medical Science and Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Yangjing Zhao
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA.,Department of Immunology, Key Laboratory of Medical Science and Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Wenli Lin
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Eddy C Hsueh
- Division of General Surgery and Department of Surgery, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Lizong Shen
- Division of Gastrointestinal Surgery, Department of General Surgery, First Affiliated Hospital, Nanjing Medical University, Nanjing 210029, P. R. China
| | - Qixiang Shao
- Department of Immunology, Key Laboratory of Medical Science and Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang 212013, P. R. China
| | - Daniel F Hoft
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA.,Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, MO 63104, USA
| | - David A Ford
- Edward A. Doisy Department of Biochemistry and Molecular Biology and Center for Cardiovascular Research, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA
| | - Guangyong Peng
- Division of Infectious Diseases, Allergy and Immunology and Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, MO 63104, USA. .,Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, MO 63104, USA
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24
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Tanshinone IIA Downregulates Lipogenic Gene Expression and Attenuates Lipid Accumulation through the Modulation of LXRα/SREBP1 Pathway in HepG2 Cells. Biomedicines 2021; 9:biomedicines9030326. [PMID: 33806955 PMCID: PMC8004631 DOI: 10.3390/biomedicines9030326] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 03/21/2021] [Accepted: 03/21/2021] [Indexed: 12/12/2022] Open
Abstract
Abnormal and excessive accumulation of lipid droplets within hepatic cells is the main feature of steatosis and nonalcoholic fatty liver disease (NAFLD) or metabolic-associated fatty liver disease (MAFLD). Dysregulation of lipogenesis contributes to hepatic steatosis and plays an essential role in the pathological progress of MAFLD. Tanshinone IIA is a bioactive phytochemical isolated from Salvia miltiorrhiza Bunge and exhibits anti-inflammatory, antiatherosclerotic and antihyperlipidemic effects. In this study, we aimed to investigate the lipid-lowering effects of tanshinone IIA on the regulation of lipogenesis, lipid accumulation, and the underlying mechanisms in hepatic cells. We demonstrated that tanshinone IIA can significantly inhibit the gene expression involved in de novo lipogenesis including FASN, ACC1, and SCD1, in HepG2 and Huh 7 cells. Tanshinone IIA could increase phosphorylation of ACC1 protein in HepG2 cells. We further demonstrated that tanshinone IIA also could suppress the fatty-acid-induced lipogenesis and TG accumulation in HepG2 cells. Furthermore, tanshinone IIA markedly downregulated the mRNA and protein expression of SREBP1, an essential transcription factor regulating lipogenesis in hepatic cells. Moreover, we found that tanshinone IIA attenuated liver X receptor α (LXRα)-mediated lipogenic gene expression and lipid droplet accumulation, but did not change the levels of LXRα mRNA or protein in HepG2 cells. The molecular docking data predicted tanshinone IIA binding to the ligand-binding domain of LXRα, which may result in the attenuation of LXRα-induced transcriptional activation. Our findings support the supposition that tanshinone IIA possesses a lipid-modulating effect that suppresses lipogenesis and attenuates lipid accumulation by modulating the LXRα/SREBP1 pathway in hepatic cells. Tanshinone IIA can be potentially used as a supplement or drug for the prevention or treatment of MAFLD.
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25
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Kinney CJ, O'Neill A, Noland K, Huang W, Muriel J, Lukyanenko V, Kane MA, Ward CW, Collier AF, Roche JA, McLenithan JC, Reed PW, Bloch RJ. μ-Crystallin in Mouse Skeletal Muscle Promotes a Shift from Glycolytic toward Oxidative Metabolism. Curr Res Physiol 2021; 4:47-59. [PMID: 34746826 PMCID: PMC8562245 DOI: 10.1016/j.crphys.2021.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 01/31/2021] [Accepted: 02/04/2021] [Indexed: 01/24/2023] Open
Abstract
μ-Crystallin, encoded by the CRYM gene, binds the thyroid hormones, T3 and T4. Because T3 and T4 are potent regulators of metabolism and gene expression, and CRYM levels in human skeletal muscle can vary widely, we investigated the effects of overexpression of Crym. We generated transgenic mice, Crym tg, that expressed Crym protein specifically in skeletal muscle at levels 2.6-147.5 fold higher than in controls. Muscular functions, Ca2+ transients, contractile force, fatigue, running on treadmills or wheels, were not significantly altered, although T3 levels in tibialis anterior (TA) muscle were elevated ~190-fold and serum T4 was decreased 1.2-fold. Serum T3 and thyroid stimulating hormone (TSH) levels were unaffected. Crym transgenic mice studied in metabolic chambers showed a significant decrease in the respiratory exchange ratio (RER) corresponding to a 13.7% increase in fat utilization as an energy source compared to controls. Female but not male Crym tg mice gained weight more rapidly than controls when fed high fat or high simple carbohydrate diets. Although labeling for myosin heavy chains showed no fiber type differences in TA or soleus muscles, application of machine learning algorithms revealed small but significant morphological differences between Crym tg and control soleus fibers. RNA-seq and gene ontology enrichment analysis showed a significant shift towards genes associated with slower muscle function and its metabolic correlate, β-oxidation. Protein expression showed a similar shift, though with little overlap. Our study shows that μ-crystallin plays an important role in determining substrate utilization in mammalian muscle and that high levels of μ-crystallin are associated with a shift toward greater fat metabolism.
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Affiliation(s)
- Christian J. Kinney
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Andrea O'Neill
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Kaila Noland
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Weiliang Huang
- Department of Pharmaceutical Sciences School of Pharmacy, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Joaquin Muriel
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Valeriy Lukyanenko
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Maureen A. Kane
- Department of Pharmaceutical Sciences School of Pharmacy, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Christopher W. Ward
- Department of Orthopedics School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Alyssa F. Collier
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Joseph A. Roche
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - John C. McLenithan
- Department of Medicine School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Patrick W. Reed
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
| | - Robert J. Bloch
- Department of Physiology School of Medicine, University of Maryland Baltimore, Baltimore, MD, 21201, USA
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26
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Zhang S, Yang Z, Li M, Zhang Q, Tian X, Li D, Li S, Wu J, Tian Y. A multi-photon fluorescent probe based on quinoline groups for the highly selective and sensitive detection of lipid droplets. Analyst 2021; 145:7941-7945. [PMID: 33030164 DOI: 10.1039/d0an01847c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Compared to general fluorescent probes, multi-photon fluorescent probes exhibit deeper tissue penetration, lower auto-fluorescence and lower photo-toxicity in the bio-imaging field. Herein, we synthesized a series multi-photon fluorescent probe (L1-L3) based on quinolone groups. Of notably, the three-photon fluorescence of L3 significantly enhanced when L3 interacted with liposome; moreover, L3 exhibited high selectivity towards lipid droplets in living cells. Due to its large Stokes shift, high selectivity and photon-stability, L3 was successfully used in lipid droplet imaging via multi-photon fluorescence bio-imaging.
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Affiliation(s)
- Sijing Zhang
- Department of Chemistry, Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province, Anhui University, Hefei 230601, P. R. China.
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27
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Parafati M, Bae SH, Kirby RJ, Fitzek M, Iyer P, Engkvist O, Smith DM, Malany S. Pluripotent Stem Cell-Derived Hepatocytes Phenotypic Screening Reveals Small Molecules Targeting the CDK2/4-C/EBPα/DGAT2 Pathway Preventing ER-Stress Induced Lipid Accumulation. Int J Mol Sci 2020; 21:ijms21249557. [PMID: 33334026 PMCID: PMC7765409 DOI: 10.3390/ijms21249557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/17/2020] [Accepted: 11/26/2020] [Indexed: 02/04/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) has a large impact on global health. At the onset of disease, NAFLD is characterized by hepatic steatosis defined by the accumulation of triglycerides stored as lipid droplets. Developing therapeutics against NAFLD and progression to non-alcoholic steatohepatitis (NASH) remains a high priority in the medical and scientific community. Drug discovery programs to identify potential therapeutic compounds have supported high throughput/high-content screening of in vitro human-relevant models of NAFLD to accelerate development of efficacious anti-steatotic medicines. Human induced pluripotent stem cell (hiPSC) technology is a powerful platform for disease modeling and therapeutic assessment for cell-based therapy and personalized medicine. In this study, we applied AstraZeneca’s chemogenomic library, hiPSC technology and multiplexed high content screening to identify compounds that significantly reduced intracellular neutral lipid content. Among 13,000 compounds screened, we identified hits that protect against hiPSC-derived hepatic endoplasmic reticulum stress-induced steatosis by a mechanism of action including inhibition of the cyclin D3-cyclin-dependent kinase 2-4 (CDK2-4)/CCAAT-enhancer-binding proteins (C/EBPα)/diacylglycerol acyltransferase 2 (DGAT2) pathway, followed by alteration of the expression of downstream genes related to NAFLD. These findings demonstrate that our phenotypic platform provides a reliable approach in drug discovery, to identify novel drugs for treatment of fatty liver disease as well as to elucidate their underlying mechanisms.
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Affiliation(s)
- Maddalena Parafati
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA; (M.P.); (S.H.B.)
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA;
| | - Sang Hyo Bae
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA; (M.P.); (S.H.B.)
| | - R. Jason Kirby
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA;
| | - Martina Fitzek
- Hit Discovery, Discovery Sciences, R&D, AstraZeneca, Alderley Park, Macclesfield SK10 4TG, UK;
| | - Preeti Iyer
- Molecular AI, Discovery Sciences, R&D, AstraZeneca, 431 83 Mölndal, Sweden; (P.I.); (O.E.)
| | - Ola Engkvist
- Molecular AI, Discovery Sciences, R&D, AstraZeneca, 431 83 Mölndal, Sweden; (P.I.); (O.E.)
| | - David M. Smith
- Emerging Innovations Unit, Discovery Sciences, R&D, AstraZeneca, Cambridge SG8 6HB, UK;
| | - Siobhan Malany
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA; (M.P.); (S.H.B.)
- Conrad Prebys Center for Chemical Genomics, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA;
- Correspondence: ; Tel.: +352-273-6400
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28
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Liver X receptor α participates in LPS-induced reduction of triglyceride synthesis in bovine mammary epithelial cells. J DAIRY RES 2020; 87:456-462. [PMID: 33261669 DOI: 10.1017/s0022029920000990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Lipopolysaccharides (LPS) could induce milk fat depression via regulating the body and blood fat metabolism. However, it is not completely clear how LPS might regulate triglyceride synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS. The level of triglyceride synthesis, the expression and activity of the liver X receptor α (LXRα), enzymes related to de novo fatty acid synthesis, and the expression of the fatty acid transporters were investigated. We found that LPS decreased the level of triglyceride synthesis via a down-regulation of the transcription, translation, and nuclear translocation level of the LXRα. The results also indicated that the transcription level of the LXRα target genes, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthetase (FAS), acetyl-CoA carboxylase-1 (ACC1), were significantly down-regulated in DCMECs after LPS treatment. Our data may provide new insight into the mechanisms of milk fat depression caused by LPS.
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29
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A novel tracer for in vivo optical imaging of fatty acid metabolism in the heart and brown adipose tissue. Sci Rep 2020; 10:11209. [PMID: 32641756 PMCID: PMC7343860 DOI: 10.1038/s41598-020-68065-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 06/16/2020] [Indexed: 12/04/2022] Open
Abstract
Multiplexed imaging is essential for the evaluation of substrate utilization in metabolically active organs, such as the heart and brown adipose tissue (BAT), where substrate preference changes in pathophysiologic states. Optical imaging provides a useful platform because of its low cost, high throughput and intrinsic ability to perform composite readouts. However, the paucity of probes available for in vivo use has limited optical methods to image substrate metabolism. Here, we present a novel near-infrared (NIR) free fatty acid (FFA) tracer suitable for in vivo imaging of deep tissues such as the heart. Using click chemistry, Alexa Fluor 647 DIBO Alkyne was conjugated to palmitic acid. Mice injected with 0.05 nmol/g bodyweight of the conjugate (AlexaFFA) were subjected to conditions known to increase FFA uptake in the heart (fasting) and BAT [cold exposure and injection with the β3 adrenergic agonist CL 316, 243(CL)]. Organs were subsequently imaged both ex vivo and in vivo to quantify AlexaFFA uptake. The blood kinetics of AlexaFFA followed a two-compartment model with an initial fast compartment half-life of 0.14 h and a subsequent slow compartment half-life of 5.2 h, consistent with reversible protein binding. Ex vivo fluorescence imaging after overnight cold exposure and fasting produced a significant increase in AlexaFFA uptake in the heart (58 ± 12%) and BAT (278 ± 19%) compared to warm/fed animals. In vivo imaging of the heart and BAT after exposure to CL and fasting showed a significant increase in AlexaFFA uptake in the heart (48 ± 20%) and BAT (40 ± 10%) compared to saline-injected/fed mice. We present a novel near-infrared FFA tracer, AlexaFFA, that is suitable for in vivo quantification of FFA metabolism and can be applied in the context of a low cost, high throughput, and multiplexed optical imaging platform.
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30
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Strauss JA, Shepherd DA, Macey M, Jevons EFP, Shepherd SO. Divergence exists in the subcellular distribution of intramuscular triglyceride in human skeletal muscle dependent on the choice of lipid dye. Histochem Cell Biol 2020; 154:369-382. [PMID: 32627050 PMCID: PMC7532971 DOI: 10.1007/s00418-020-01898-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2020] [Indexed: 01/19/2023]
Abstract
Despite over 50 years of research, a comprehensive understanding of how intramuscular triglyceride (IMTG) is stored in skeletal muscle and its contribution as a fuel during exercise is lacking. Immunohistochemical techniques provide information on IMTG content and lipid droplet (LD) morphology on a fibre type and subcellular-specific basis, and the lipid dye Oil Red O (ORO) is commonly used to achieve this. BODIPY 493/503 (BODIPY) is an alternative lipid dye with lower background staining and narrower emission spectra. Here we provide the first quantitative comparison of BODIPY and ORO for investigating exercise-induced changes in IMTG content and LD morphology on a fibre type and subcellular-specific basis. Estimates of IMTG content were greater when using BODIPY, which was predominantly due to BODIPY detecting a larger number of LDs, compared to ORO. The subcellular distribution of intramuscular lipid was also dependent on the lipid dye used; ORO detects a greater proportion of IMTG in the periphery (5 μm below cell membrane) of the fibre, whereas IMTG content was higher in the central region using BODIPY. In response to 60 min moderate-intensity cycling exercise, IMTG content was reduced in both the peripheral (− 24%) and central region (− 29%) of type I fibres (P < 0.05) using BODIPY, whereas using ORO, IMTG content was only reduced in the peripheral region of type I fibres (− 31%; P < 0.05). As well as highlighting some methodological considerations herein, our investigation demonstrates that important differences exist between BODIPY and ORO for detecting and quantifying IMTG on a fibre type and subcellular-specific basis.
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Affiliation(s)
- Juliette A Strauss
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK.
| | - Daisy A Shepherd
- Clinical Epidemiology and Biostatistics Unit, Murdoch Children's Research Institute, Royal Children's Hospital, Victoria, 3052, Australia.,Department of Paediatrics, The University of Melbourne, Victoria, 3010, Australia
| | - Myfanwy Macey
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Emily F P Jevons
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Sam O Shepherd
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, L3 3AF, UK
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31
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Colavita JPM, Todaro JS, de Sousa M, May M, Gómez N, Yaneff A, Di Siervi N, Aguirre MV, Guijas C, Ferrini L, Davio C, Rodríguez JP. Multidrug resistance protein 4 (MRP4/ABCC4) is overexpressed in clear cell renal cell carcinoma (ccRCC) and is essential to regulate cell proliferation. Int J Biol Macromol 2020; 161:836-847. [PMID: 32553977 DOI: 10.1016/j.ijbiomac.2020.06.106] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022]
Abstract
Kidney cancer accounts for 2.5% of all cancers, with an annual global incidence of almost 300,000 cases leading to 111,000 deaths. Approximately 85% of kidney tumors are renal cell carcinoma (RCC) and their major histologic subtype is clear cell renal cell carcinoma (ccRCC). Although new therapeutic treatments are being designed and applied based on the combination of tyrosine kinase inhibitors and immunotherapy, no major impact on the mortality has been reported so far. MRP4 is a pump efflux that transporters multiple endogenous and exogenous substances. Recently it has been associated with tumoral persistence and cell proliferation in several types of cancer including pancreas, lung, ovary, colon, ostesarcoma, etc. Herein, we demonstrate for the first time, that MRP4 is overexpressed in ccRCC tumors, compared to control renal tissues. In addition, using cell culture models, we observed that MRP4 pharmacological inhibition produces an imbalance in cAMP metabolism, induces cell arrest, changes in lipid composition, increase in cytoplasmic lipid droplets and finally apoptosis. These data provide solid evidence for the future evaluation of MRP4 as a possible new therapeutic target in ccRCC.
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Affiliation(s)
- Juan Pablo Melana Colavita
- Laboratorio de Investigaciones Bioquímicas de la Facultad de Medicina (LIBIM), Instituto de Química Básica y Aplicada del NEA, (IQUIBA NEA-UNNE-CONICET), Facultad de Medicina, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina
| | - Juan Santiago Todaro
- Laboratorio de Investigaciones Bioquímicas de la Facultad de Medicina (LIBIM), Instituto de Química Básica y Aplicada del NEA, (IQUIBA NEA-UNNE-CONICET), Facultad de Medicina, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina
| | - Maximiliano de Sousa
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - María May
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - Natalia Gómez
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - Agustin Yaneff
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - Nicolas Di Siervi
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - María Victoria Aguirre
- Laboratorio de Investigaciones Bioquímicas de la Facultad de Medicina (LIBIM), Instituto de Química Básica y Aplicada del NEA, (IQUIBA NEA-UNNE-CONICET), Facultad de Medicina, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina
| | - Carlos Guijas
- Instituto de Biología y Genética Molecular, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Valladolid, 47003 Valladolid, Spain
| | - Leandro Ferrini
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - Carlos Davio
- Instituto de Investigaciones Farmacológicas (ININFA-UBA-CONICET), Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, 1000 Buenos Aires, Argentina
| | - Juan Pablo Rodríguez
- Laboratorio de Investigaciones Bioquímicas de la Facultad de Medicina (LIBIM), Instituto de Química Básica y Aplicada del NEA, (IQUIBA NEA-UNNE-CONICET), Facultad de Medicina, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina.
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32
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Yoshihara T, Maruyama R, Shiozaki S, Yamamoto K, Kato SI, Nakamura Y, Tobita S. Visualization of Lipid Droplets in Living Cells and Fatty Livers of Mice Based on the Fluorescence of π-Extended Coumarin Using Fluorescence Lifetime Imaging Microscopy. Anal Chem 2020; 92:4996-5003. [PMID: 32126762 DOI: 10.1021/acs.analchem.9b05184] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lipid droplets (LDs) are closely related to lipid metabolism in living cells and are highly associated with diverse diseases such as fatty liver, diabetes, and cancer. Herein we describe a π-extended fluorescent coumarin (PC6S) for visualizing LDs in living cells and in the tissues of living mice using confocal fluorescence lifetime imaging microscopy (FLIM). PC6S showed a large positive solvatochromic shift and high fluorescence quantum yield (>0.80) in both nonpolar and polar solvents. Additionally, the fluorescence lifetimes of PC6S were largely dependent on solvent polarity. The excellent spectral and photophysical properties of PC6S allowed its selective staining of LDs in living and fixed cells, and multicolor imaging. Fluorescence lifetime measurements of PC6S allowed estimation of the apparent polarity of LDs. The high photostability and long intracellular retention of PC6S supported in situ visualization of the formation processes of LDs resulting from the accumulation of fatty acid. Furthermore, intravenous administration of PC6S and use of the FLIM system allowed the imaging of LDs in hepatocytes in living normal mice and the growth of LDs resulting from the excess accumulation of lipids in high-fat-diet-fed mice (fatty liver model mice). Taking advantage of the high selectivity and sensitivity of PC6S for LDs in liver, we could visualize the adipocytes of lipid-rich tissues and LDs in kidney peritubular cells by PC6S fluorescence. These results demonstrated that PC6S combined with a FLIM system can be useful for monitoring and tracking the formation of LDs in both cultured cells and specific tissues and organs.
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Affiliation(s)
- Toshitada Yoshihara
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Ryo Maruyama
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Shuichi Shiozaki
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Koji Yamamoto
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Shin-Ichiro Kato
- Department of Material Science, School of Engineering, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga 522-8533, Japan
| | - Yosuke Nakamura
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Seiji Tobita
- Department of Chemistry and Chemical Biology, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
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Shi X, Sung SHP, Lee MMS, Kwok RTK, Sung HHY, Liu H, Lam JWY, Williams ID, Liu B, Tang BZ. A lipophilic AIEgen for lipid droplet imaging and evaluation of the efficacy of HIF-1 targeting drugs. J Mater Chem B 2020; 8:1516-1523. [DOI: 10.1039/c9tb02848j] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A lipid-droplet-specific AIEgen was used to evaluate the inhibitory efficacy of HIF-1-targeting drugs by assessing lipid-droplet levels.
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Lee J, Hyon JY, Min JY, Huh YH, Kim HJ, Lee H, Yun SH, Choi CW, Jeong Ha S, Park J, Chung YH, Jeong HG, Ha SK, Jung SK, Kim Y, Han EH. Mitochondrial carnitine palmitoyltransferase 2 is involved in N ε-(carboxymethyl)-lysine-mediated diabetic nephropathy. Pharmacol Res 2019; 152:104600. [PMID: 31838081 DOI: 10.1016/j.phrs.2019.104600] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 11/20/2019] [Accepted: 12/11/2019] [Indexed: 12/24/2022]
Abstract
Diabetic nephropathy (DN) is the most common cause of end-stage renal disease in the world. Advanced glycation end products (AGEs) are thought to be involved in the pathogenesis of DN via multifactorial mechanisms including the generation of oxidative stress and overproduction of various growth factors and cytokines. AGEs are heterogeneous cross-linked sugar-derived proteins, and Nε-(carboxymethyl)-lysine (CML)-conjugated BSA is a major component of AGEs. However, the proteins involved in DN induction by CML have never been reported. Herein, we investigated specific protein regulators of AGE-mediated DN via proteomic analysis of streptozotocin (STZ)-induced diabetic mice kidneys. We identified 937, 976, and 870 proteins in control, STZ, and STZ + CML-BSA samples, respectively. Bioinformatics analysis identified several CML-mediated proteins potentially involved in kidney damage, activation of fatty acid oxidation (FAO), and mitochondrial dysfunction. Furthermore, we identified the CML-specific differential protein carnitine palmitoyltransferase 2 (CPT2), related to FAO. To confirm the effect of CPT2 and the CML-mediated mechanism, human renal tubular HK-2 cells were treated with CML-BSA and cpt2 siRNA, and examined for FAO-mediated fibrosis and mitochondrial dysfunction. CML-BSA and CPT2 knockdown induced fibrosis-related gene expression and damage to mitochondrial membrane potential. Moreover, CPT2 overexpression recovered CML-induced fibrosis-related gene expression. Based on these results, a decrease in CML-induced CPT2 expression causes mitochondrial FAO damage, leading to renal fibrosis and DN.
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MESH Headings
- Animals
- Blood Glucose/analysis
- Carnitine O-Palmitoyltransferase/genetics
- Cell Line
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 1/chemically induced
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/pathology
- Diabetic Nephropathies/chemically induced
- Diabetic Nephropathies/genetics
- Diabetic Nephropathies/metabolism
- Diabetic Nephropathies/pathology
- Glycated Hemoglobin/analysis
- Humans
- Kidney/metabolism
- Kidney/pathology
- Lysine/analogs & derivatives
- Male
- Membrane Potential, Mitochondrial
- Mice, Inbred C57BL
- Mitochondria/enzymology
- Mitochondria/physiology
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Affiliation(s)
- Jangho Lee
- Korea Food Research Institute (KFRI), Jeollabuk-do, 55365, South Korea
| | - Ju-Yong Hyon
- Korea University, Seoul 02841, South Korea; Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea
| | - Jin Young Min
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea; Chungnam National University, Daejeon, 34134, South Korea
| | - Yang Hoon Huh
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea
| | - Hyo Jung Kim
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea
| | - Hayoung Lee
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea; Korea University of Science and Technology (UST), Daejeon 34113, South Korea
| | - Sung Ho Yun
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea
| | - Chi-Won Choi
- KBNP Technology Institute, Anyang 14009, South Korea
| | - Su Jeong Ha
- Korea Food Research Institute (KFRI), Jeollabuk-do, 55365, South Korea; Seoul National University, Seoul 08826, South Korea
| | - Joon Park
- Korea Food Research Institute (KFRI), Jeollabuk-do, 55365, South Korea; Korea University of Science and Technology (UST), Daejeon 34113, South Korea
| | - Young-Ho Chung
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea; Chungnam National University, Daejeon, 34134, South Korea
| | | | - Sang Keun Ha
- Korea Food Research Institute (KFRI), Jeollabuk-do, 55365, South Korea
| | - Sung Keun Jung
- Kyungpook National University, Daegu 41566, South Korea.
| | - YoonSook Kim
- Korea Food Research Institute (KFRI), Jeollabuk-do, 55365, South Korea.
| | - Eun Hee Han
- Korea Basic Science Institute (KBSI), Cheongju 28119, South Korea.
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Petroff JT, Grady S, Arnatt CK, McCulla RD. Dibenzothiophene Sulfone Derivatives as Plasma Membrane Dyes. Photochem Photobiol 2019; 96:67-73. [DOI: 10.1111/php.13175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 10/15/2019] [Indexed: 01/06/2023]
Affiliation(s)
| | - Scott Grady
- Department of Chemistry Saint Louis University St. Louis MO
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Tytgat L, Van Damme L, Ortega Arevalo MDP, Declercq H, Thienpont H, Otteveare H, Blondeel P, Dubruel P, Van Vlierberghe S. Extrusion-based 3D printing of photo-crosslinkable gelatin and κ-carrageenan hydrogel blends for adipose tissue regeneration. Int J Biol Macromol 2019; 140:929-938. [DOI: 10.1016/j.ijbiomac.2019.08.124] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 01/19/2023]
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Cook NL, Pjanic M, Emmerich AG, Rao AS, Hetty S, Knowles JW, Quertermous T, Castillejo-López C, Ingelsson E. CRISPR-Cas9-mediated knockout of SPRY2 in human hepatocytes leads to increased glucose uptake and lipid droplet accumulation. BMC Endocr Disord 2019; 19:115. [PMID: 31664995 PMCID: PMC6820957 DOI: 10.1186/s12902-019-0442-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/10/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The prevalence of obesity and its comorbidities, including type 2 diabetes mellitus (T2DM), is dramatically increasing throughout the world; however, the underlying aetiology is incompletely understood. Genome-wide association studies (GWAS) have identified hundreds of genec susceptibility loci for obesity and T2DM, although the causal genes and mechanisms are largely unknown. SPRY2 is a candidate gene identified in GWAS of body fat percentage and T2DM, and has recently been linked to insulin production in pancreatic β-cells. In the present study, we aimed to further understand SPRY2 via functional characterisation in HepG2 cells, an in vitro model of human hepatocytes widely used to investigate T2DM and insulin resistance. METHODS CRISPR-Cas9 genome editing was used to target SPRY2 in HepG2 cells, and the functional consequences of SPRY2 knockout (KO) and overexpression subsequently assessed using glucose uptake and lipid droplet assays, measurement of protein kinase phosphorylation and RNA sequencing. RESULTS The major functional consequence of SPRY2 KO was a significant increase in glucose uptake, along with elevated lipid droplet accumulation. These changes were attenuated, but not reversed, in cells overexpressing SPRY2. Phosphorylation of protein kinases across key signalling pathways (including Akt and mitogen activated protein kinases) was not altered after SPRY2 KO. Transcriptome profiling in SPRY2 KO and mock (control) cells revealed a number of differentially expressed genes related to cholesterol biosynthesis, cell cycle regulation and cellular signalling pathways. Phospholipase A2 group IIA (PLA2G2A) mRNA level was subsequently validated as significantly upregulated following SPRY2 KO, highlighting this as a potential mediator downstream of SPRY2. CONCLUSION These findings suggest a role for SPRY2 in glucose and lipid metabolism in hepatocytes and contribute to clarifying the function of this gene in the context of metabolic diseases.
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Affiliation(s)
- Naomi L Cook
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Milos Pjanic
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Andrew G Emmerich
- Molecular Systems Biology, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Abhiram S Rao
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Susanne Hetty
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Joshua W Knowles
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA
| | - Thomas Quertermous
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA
- Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA
| | - Casimiro Castillejo-López
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
- Department of Immunology, Genetics and Pathology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Erik Ingelsson
- Molecular Epidemiology and Science for Life Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, USA.
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, USA.
- Stanford Diabetes Research Center, Stanford University, Stanford, CA, USA.
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Huang TY, Zheng D, Hickner RC, Brault JJ, Cortright RN. Peroxisomal gene and protein expression increase in response to a high-lipid challenge in human skeletal muscle. Metabolism 2019; 98:53-61. [PMID: 31226353 PMCID: PMC7031862 DOI: 10.1016/j.metabol.2019.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 05/22/2019] [Accepted: 06/14/2019] [Indexed: 12/13/2022]
Abstract
Peroxisomes are essential for lipid metabolism and disruption of liver peroxisomal function results in neonatal death. Little is known about how peroxisomal content and activity respond to changes in the lipid environment in human skeletal muscle (HSkM). AIMS We hypothesized and tested that increased peroxisomal gene/protein expression and functionality occur in HSkM as an adaptive response to lipid oversupply. MATERIALS AND METHODS HSkM biopsies, derived from a total of sixty-two subjects, were collected for 1) examining correlations between peroxisomal proteins and intramyocellular lipid content (IMLC) as well as between peroxisomal functionality and IMLC, 2) assessing peroxisomal gene expression in response to acute- or 7-day high fat meal (HFM), and in human tissue derived primary myotubes for 3) treating with high fatty acids to induce peroxisomal adaptions. IMLC were measured by both biochemical analyses and fluorescent staining. Peroxisomal membrane protein PMP70 and biogenesis gene (PEX) expression were assessed using western blotting and realtime qRT-PCR respectively. 1-14C radiolabeled lignocerate and palmitate oxidation assays were performed for peroxisomal and mitochondrial functionality respectively. RESULTS 1) Under fasting conditions, HSkM tissue demonstrated a significant correlation (P ≪ 0.05) between IMCL and the peroxisomal biogenesis factor 19 (PEX19) protein as well as between lipid content and palmitate and lignocerate complete oxidation. 2) Similarly, post-HFM, additional PEX genes (Pex19, PEX11A, and PEX5) were significantly (P ≪ 0.05) upregulated. 3) Increments in PMP70, carnitine octanoyl transferase (CrOT), PGC-1α, and ERRα mRNA were observed post-fatty acid incubation in HSkM cells. PMP70 protein was significantly (P ≪ 0.05) elevated 48-h post lipid treatment. CONCLUSIONS These results are the first to associate IMLC with peroxisomal gene/protein expression and function in HSkM suggesting an adaptive role for peroxisomes in lipid metabolism in this tissue.
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Affiliation(s)
- Tai-Yu Huang
- Department of Kinesiology, East Carolina University, Greenville, NC, United States of America
| | - Donghai Zheng
- Department of Kinesiology, East Carolina University, Greenville, NC, United States of America; Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States of America
| | - Robert C Hickner
- Department of Kinesiology, East Carolina University, Greenville, NC, United States of America; Department of Physiology, East Carolina University, Greenville, NC, United States of America; Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States of America; College of Human Sciences, Florida State University, Tallahassee, FL, United States of America; School of Health Sciences, University of KwaZulu-Natal, Westville, South Africa
| | - Jeffrey J Brault
- Department of Kinesiology, East Carolina University, Greenville, NC, United States of America; Department of Physiology, East Carolina University, Greenville, NC, United States of America; Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States of America
| | - Ronald N Cortright
- Department of Kinesiology, East Carolina University, Greenville, NC, United States of America; Department of Physiology, East Carolina University, Greenville, NC, United States of America; Department of Surgery, East Carolina University, Greenville, NC, United States of America; Diabetes and Obesity Institute, East Carolina University, Greenville, NC, United States of America.
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Tytgat L, Van Damme L, Van Hoorick J, Declercq H, Thienpont H, Ottevaere H, Blondeel P, Dubruel P, Van Vlierberghe S. Additive manufacturing of photo-crosslinked gelatin scaffolds for adipose tissue engineering. Acta Biomater 2019; 94:340-350. [PMID: 31136829 DOI: 10.1016/j.actbio.2019.05.062] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/20/2019] [Accepted: 05/23/2019] [Indexed: 01/22/2023]
Abstract
There exists a clear clinical need for adipose tissue reconstruction strategies to repair soft tissue defects which outperform the currently available approaches. In this respect, additive manufacturing has shown to be a promising alternative for the development of larger constructs able to support adipose tissue engineering. In the present work, a thiol-ene photo-click crosslinkable gelatin hydrogel was developed which allowed extrusion-based additive manufacturing into porous scaffolds. To this end, norbornene-functionalized gelatin (Gel-NB) was combined with thiolated gelatin (Gel-SH). The application of a macromolecular gelatin-based thiolated crosslinker holds several advantages over conventional crosslinkers including cell-interactivity, less chance at phase separation between scaffold material and crosslinker and the formation of a more homogeneous network. Throughout the paper, these photo-click scaffolds were benchmarked to the conventional methacrylamide-modified gelatin (Gel-MA). The results indicated that stable scaffolds could be realized which were further characterized physico-chemically by performing swelling, mechanical and in vitro biodegradability assays. Furthermore, the seeded adipose tissue-derived stem cells (ASCs) remained viable (>90%) up to 14 days and were able to proliferate. In addition, the cells could be differentiated into the adipogenic lineage on the photo-click crosslinked scaffolds, thereby performing better than the cells supported by the frequently reported Gel-MA scaffolds. As a result, the developed photo-click crosslinked scaffolds can be considered a promising candidate towards adipose tissue engineering and a valuable alternative for the omnipresent Gel-MA. STATEMENT OF SIGNIFICANCE: The field of adipose tissue engineering has emerged as a promising strategy to repair soft tissue defects. Herein, Gel-NB/Gel-SH gelatin-based hydrogel scaffolds were produced using extrusion-based additive manufacturing. Using a cell-interactive, thiolated gelatin crosslinker, a homogeneous network was formed and the risk of phase separation between norbornene-modified gelatin and macromolecular crosslinkers was reduced. UV-induced crosslinking of these materials is based on step growth polymerization which requires less free radicals to enable polymerization. Our results demonstrated the potential of the developed scaffolds, due to their favourable physico-chemical characteristics as well as their adipogenic differentiation potential when benchmarked to Gel-MA scaffolds. Hence, the hydrogels could be of great interest towards future development of adipose tissue constructs and tissue engineering in general.
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Affiliation(s)
- Liesbeth Tytgat
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium; Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium
| | - Lana Van Damme
- Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium; Department of Plastic & Reconstructive Surgery, Ghent University Hospital, Corneel Heymanslaan 10, 2K12, 9000 Ghent, Belgium
| | - Jasper Van Hoorick
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium; Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium
| | - Heidi Declercq
- Tissue Engineering and Biomaterials Group - Department of Human Structure and Repair, Ghent University, Corneel Heymanslaan 10, 6B3, 9000 Ghent, Belgium
| | - Hugo Thienpont
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Heidi Ottevaere
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Phillip Blondeel
- Department of Plastic & Reconstructive Surgery, Ghent University Hospital, Corneel Heymanslaan 10, 2K12, 9000 Ghent, Belgium
| | - Peter Dubruel
- Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium
| | - Sandra Van Vlierberghe
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium; Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium
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Mueller AL, O'Neill A, Jones TI, Llach A, Rojas LA, Sakellariou P, Stadler G, Wright WE, Eyerman D, Jones PL, Bloch RJ. Muscle xenografts reproduce key molecular features of facioscapulohumeral muscular dystrophy. Exp Neurol 2019; 320:113011. [PMID: 31306642 DOI: 10.1016/j.expneurol.2019.113011] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/17/2019] [Accepted: 07/09/2019] [Indexed: 12/07/2022]
Abstract
Aberrant expression of DUX4, a gene unique to humans and primates, causes Facioscapulohumeral Muscular Dystrophy-1 (FSHD), yet the pathogenic mechanism is unknown. As transgenic overexpression models have largely failed to replicate the genetic changes seen in FSHD, many studies of endogenously expressed DUX4 have been limited to patient biopsies and myogenic cell cultures, which never fully differentiate into mature muscle fibers. We have developed a method to xenograft immortalized human muscle precursor cells from patients with FSHD and first-degree relative controls into the tibialis anterior muscle compartment of immunodeficient mice, generating human muscle xenografts. We report that FSHD cells mature into organized and innervated human muscle fibers with minimal contamination of murine myonuclei. They also reconstitute the satellite cell niche within the xenografts. FSHD xenografts express DUX4 and DUX4 downstream targets, retain the 4q35 epigenetic signature of their original donors, and express a novel protein biomarker of FSHD, SLC34A2. Ours is the first scalable, mature in vivo human model of FSHD. It should be useful for studies of the pathogenic mechanism of the disease as well as for testing therapeutic strategies targeting DUX4 expression.
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Affiliation(s)
- Amber L Mueller
- Department of Physiology, University of Maryland, Baltimore, 655 W, Baltimore St., Baltimore, MD 21201, United States of America
| | - Andrea O'Neill
- Department of Physiology, University of Maryland, Baltimore, 655 W, Baltimore St., Baltimore, MD 21201, United States of America
| | - Takako I Jones
- Department of Pharmacology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV 89557, United States of America
| | - Anna Llach
- Department of Physiology, University of Maryland, Baltimore, 655 W, Baltimore St., Baltimore, MD 21201, United States of America
| | - Luis Alejandro Rojas
- Fulcrum Therapeutics, 26 Landsdowne St., Cambridge, MA 02139, United States of America
| | - Paraskevi Sakellariou
- Department of Physiology, University of Maryland, Baltimore, 655 W, Baltimore St., Baltimore, MD 21201, United States of America; FAME Laboratory Department of Exercise Science, University of Thessaly, Karies, Trikala 42100, Greece
| | - Guido Stadler
- Department of Cell Biology, UT Southwestern Medical Center Dallas, TX 75390, United States of America
| | - Woodring E Wright
- Department of Cell Biology, UT Southwestern Medical Center Dallas, TX 75390, United States of America
| | - David Eyerman
- Fulcrum Therapeutics, 26 Landsdowne St., Cambridge, MA 02139, United States of America
| | - Peter L Jones
- Department of Pharmacology, University of Nevada, Reno School of Medicine, 1664 North Virginia Street, Reno, NV 89557, United States of America
| | - Robert J Bloch
- Department of Physiology, University of Maryland, Baltimore, 655 W, Baltimore St., Baltimore, MD 21201, United States of America.
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Niu J, Liu Y, Wang W, Lin W. Novel two-photon fluorescent probe with high fluorescence quantum yields for tracking lipid droplets in biological systems. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 216:35-44. [PMID: 30877892 DOI: 10.1016/j.saa.2019.02.106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/20/2019] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
Lipid droplets (LDs) played an important role in storing neutral lipids process. In this work, we developed a series of fluorescent dyes PIE1-PIE4 with high fluorescence quantum yields based on a single phenanthrenequinone imidazole fluorophore core. Among these compounds, we introduced diethyl aniline group on the phenanthrenequinone imidazole core to provide the compound PIE1. It is firstly found that PIE1 could real-color image and track lipid droplets (LDs) in living cells. However, we modified nitrile, imidazole and methyl group on the same fluorophore core to afford three dyes PIE2, PIE3 and PIE4, respectively. Although PIE2, PIE3 and PIE4 possessed high fluorescence quantum yields in various organic solvents, they could not real-color image and track LDs in living cells.
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Affiliation(s)
- Jie Niu
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China
| | - Yong Liu
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China
| | - Weishan Wang
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China
| | - Weiying Lin
- Institute of Fluorescent Probes for Biological Imaging, School of Materials Science and Engineering, School of Chemistry and Chemical Engineering, University of Jinan, Shandong 250022, PR China.
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Tardelli M, Bruschi FV, Claudel T, Fuchs CD, Auer N, Kunczer V, Stojakovic T, Scharnagl H, Habib A, Grabner GF, Zimmermann R, Lotersztajn S, Trauner M. Lack of monoacylglycerol lipase prevents hepatic steatosis by favoring lipid storage in adipose tissue and intestinal malabsorption. J Lipid Res 2019; 60:1284-1292. [PMID: 31048404 DOI: 10.1194/jlr.m093369] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 05/02/2019] [Indexed: 12/14/2022] Open
Abstract
Monoacylglycerol lipase (MGL) is the rate-limiting enzyme in the degradation of monoacylglycerols. To examine the role of MGL in hepatic steatosis, WT and MGL KO (MGL-/-) mice were challenged with a Western diet (WD) over 12 weeks. Lipid metabolism, inflammation, and fibrosis were assessed by serum biochemistry, histology, and gene-expression profiling of liver and adipose depots. Intestinal fat absorption was measured by gas chromatography. Primary adipocyte and 3T3-L1 cells were analyzed by flow cytometry and Western blot. Human hepatocytes were treated with MGL inhibitor JZL184. The absence of MGL protected mice from hepatic steatosis by repressing key lipogenic enzymes in liver (Srebp1c, Pparγ2, and diacylglycerol O-acyltransferase 1), while promoting FA oxidation. Liver inflammation was diminished in MGL-/- mice fed a WD, as evidenced by diminished epidermal growth factor-like module-containing mucin-like hormone receptor-like 1 (F4/80) staining and C-C motif chemokine ligand 2 gene expression, whereas fibrosis remained unchanged. Absence of MGL promoted fat storage in gonadal white adipose tissue (gWAT) with increased lipogenesis and unchanged lipolysis, diminished inflammation in gWAT, and subcutaneous AT. Intestinal fat malabsorption prevented ectopic lipid accumulation in livers of MGL-/- mice fed a WD. In vitro experiments demonstrated increased adipocyte size/lipid content driven by PPARγ. In conclusion, our data uncover that MGL deletion improves some aspects of nonalcoholic fatty liver disease by promoting lipid storage in gWAT and fat malabsorption.
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Affiliation(s)
- Matteo Tardelli
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Francesca V Bruschi
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Thierry Claudel
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Claudia D Fuchs
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Nicole Auer
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Victoria Kunczer
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
| | - Tatjana Stojakovic
- Clinical Institute of Medical and Chemical Laboratory Diagnostics University Hospital Graz, Graz, Austria
| | - Hubert Scharnagl
- Clinical Institute of Medical and Chemical Laboratory Diagnostics Medical University of Graz, Graz, Austria
| | - Aida Habib
- INSERM-UMR1149, Centre de Recherche sur l'Inflammation, Paris, France.,Department of Biochemistry and Molecular Genetics American University of Beirut, Beirut, Lebanon
| | - Gernot F Grabner
- Institute of Molecular Biosciences University of Graz, Graz, Austria
| | - Robert Zimmermann
- Institute of Molecular Biosciences University of Graz, Graz, Austria
| | | | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria
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43
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Pataky MW, Yu CS, Nie Y, Arias EB, Singh M, Mendias CL, Ploutz-Snyder RJ, Cartee GD. Skeletal muscle fiber type-selective effects of acute exercise on insulin-stimulated glucose uptake in insulin-resistant, high-fat-fed rats. Am J Physiol Endocrinol Metab 2019; 316:E695-E706. [PMID: 30753114 PMCID: PMC6580167 DOI: 10.1152/ajpendo.00482.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Insulin-stimulated glucose uptake (GU) by skeletal muscle is enhanced several hours after acute exercise in rats with normal or reduced insulin sensitivity. Skeletal muscle is composed of multiple fiber types, but exercise's effect on fiber type-specific insulin-stimulated GU in insulin-resistant muscle was previously unknown. Male rats were fed a high-fat diet (HFD; 2 wk) and were either sedentary (SED) or exercised (2-h exercise). Other, low-fat diet-fed (LFD) rats remained SED. Rats were studied immediately postexercise (IPEX) or 3 h postexercise (3hPEX). Epitrochlearis muscles from IPEX rats were incubated in 2-deoxy-[3H]glucose (2-[3H]DG) without insulin. Epitrochlearis muscles from 3hPEX rats were incubated with 2-[3H]DG ± 100 µU/ml insulin. After single fiber isolation, GU and fiber type were determined. Glycogen and lipid droplets (LDs) were assessed histochemically. GLUT4 abundance was determined by immunoblotting. In HFD-SED vs. LFD-SED rats, insulin-stimulated GU was decreased in type IIB, IIX, IIAX, and IIBX fibers. Insulin-independent GU IPEX was increased and glycogen content was decreased in all fiber types (types I, IIA, IIB, IIX, IIAX, and IIBX). Exercise by HFD-fed rats enhanced insulin-stimulated GU in all fiber types except type I. Single fiber analyses enabled discovery of striking fiber type-specific differences in HFD and exercise effects on insulin-stimulated GU. The fiber type-specific differences in insulin-stimulated GU postexercise in insulin-resistant muscle were not attributable to a lack of fiber recruitment, as indirectly evidenced by insulin-independent GU and glycogen IPEX, differences in multiple LD indexes, or altered GLUT4 abundance, implicating fiber type-selective differences in the cellular processes responsible for postexercise enhancement of insulin-mediated GLUT4 translocation.
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MESH Headings
- Animals
- Diet, High-Fat
- Glucose/metabolism
- Glucose Transporter Type 4/metabolism
- Glycogen/metabolism
- Insulin/pharmacology
- Insulin Resistance
- Lipid Droplets/metabolism
- Male
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/metabolism
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Physical Conditioning, Animal
- Rats
- Rats, Wistar
- Sedentary Behavior
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Affiliation(s)
- Mark W Pataky
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Carmen S Yu
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Yilin Nie
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Edward B Arias
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Manak Singh
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
| | - Christopher L Mendias
- Hospital for Special Surgery and Department of Physiology and Biophysics, Weill Cornell Medical College , New York, New York
| | | | - Gregory D Cartee
- Muscle Biology Laboratory, School of Kinesiology, University of Michigan , Ann Arbor, Michigan
- Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
- Institute of Gerontology, University of Michigan , Ann Arbor, Michigan
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44
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Jensen CF, Bartels ED, Braunstein TH, Nielsen LB, Holstein‐Rathlou N, Axelsen LN, Nielsen MS. Acute intramyocardial lipid accumulation in rats does not slow cardiac conduction per se. Physiol Rep 2019; 7:e14049. [PMID: 30968589 PMCID: PMC6456446 DOI: 10.14814/phy2.14049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 03/12/2019] [Accepted: 03/12/2019] [Indexed: 01/14/2023] Open
Abstract
Diabetic patients suffer from both cardiac lipid accumulation and an increased risk of arrhythmias and sudden cardiac death. This correlation suggests a link between diabetes induced cardiac steatosis and electrical abnormalities, however, the underlying mechanism remains unknown. We previously showed that cardiac conduction velocity slows in Zucker diabetic fatty rats and in fructose-fat fed rats, models that both exhibit prominent cardiac steatosis. The aim of this study was to investigate whether acute cardiac lipid accumulation reduces conduction velocity per se. Cardiac lipid accumulation was induced acutely by perfusing isolated rat hearts with palmitate-glucose buffer, or subacutely by fasting rats overnight. Subsequently, longitudinal cardiac conduction velocity was measured in right ventricular tissue strips, and intramyocardial triglyceride and lipid droplet content was determined by thin layer chromatography and BODIPY staining, respectively. Perfusion with palmitate-glucose buffer significantly increased intramyocardial triglyceride levels compared to perfusion with glucose (2.16 ± 0.17 (n = 10) vs. 0.92 ± 0.33 nmol/mg WW (n = 9), P < 0.01), but the number of lipid droplets was very low in both groups. Fasting of rats, however, resulted in both significantly elevated intramyocardial triglyceride levels compared to fed rats (3.27 ± 0.43 (n = 10) vs. 1.45 ± 0.24 nmol/mg WW (n = 10)), as well as a larger volume of lipid droplets (0.60 ± 0.13 (n = 10) vs. 0.21 ± 0.06% (n = 10), P < 0.05). There was no significant difference in longitudinal conduction velocity between palmitate-glucose perfused and control hearts (0.77 ± 0.025 (n = 10) vs. 0.75 m/sec ± 0.029 (n = 9)), or between fed and fasted rats (0.75 ± 0.042 m/sec (n = 10) vs. 0.79 ± 0.047 (n = 10)). In conclusion, intramyocardial lipid accumulation does not slow cardiac longitudinal conduction velocity per se. This is true for both increased intramyocardial triglyceride content, induced by palmitate-glucose perfusion, and increased intramyocardial triglyceride and lipid droplet content, generated by fasting.
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Affiliation(s)
- Christa F. Jensen
- Department of Biomedical SciencesFaculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Emil D. Bartels
- Department of Clinical BiochemistryCopenhagen University Hospital RigshospitaletCopenhagenDenmark
| | - Thomas H. Braunstein
- Department of Biomedical SciencesFaculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Lars B. Nielsen
- Department of Clinical BiochemistryCopenhagen University Hospital RigshospitaletCopenhagenDenmark
| | | | - Lene N. Axelsen
- Department of Biomedical SciencesFaculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Morten Schak Nielsen
- Department of Biomedical SciencesFaculty of Health SciencesUniversity of CopenhagenCopenhagenDenmark
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45
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Xu H, Zhang H, Liu G, Kong L, Zhu X, Tian X, Zhang Z, Zhang R, Wu Z, Tian Y, Zhou H. Coumarin-Based Fluorescent Probes for Super-resolution and Dynamic Tracking of Lipid Droplets. Anal Chem 2018; 91:977-982. [DOI: 10.1021/acs.analchem.8b04079] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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46
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Stable Isotope-Labeled Lipidomics to Unravel the Heterogeneous Development Lipotoxicity. Molecules 2018; 23:molecules23112862. [PMID: 30400243 PMCID: PMC6278256 DOI: 10.3390/molecules23112862] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/29/2018] [Accepted: 10/30/2018] [Indexed: 12/22/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) as a global health problem has clinical manifestations ranging from simple non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH), cirrhosis, and cancer. The role of different types of fatty acids in driving the early progression of NAFL to NASH is not understood. Lipid overload causing lipotoxicity and inflammation has been considered as an essential pathogenic factor. To correlate the lipid profiles with cellular lipotoxicity, we utilized palmitic acid (C16:0)- and especially unprecedented palmitoleic acid (C16:1)-induced lipid overload HepG2 cell models coupled with lipidomic technology involving labeling with stable isotopes. C16:0 induced inflammation and cell death, whereas C16:1 induced significant lipid droplet accumulation. Moreover, inhibition of de novo sphingolipid synthesis by myriocin (Myr) aggravated C16:0 induced lipoapoptosis. Lipid profiles are different in C16:0 and C16:1-treated cells. Stable isotope-labeled lipidomics elucidates the roles of specific fatty acids that affect lipid metabolism and cause lipotoxicity or lipid droplet formation. It indicates that not only saturation or monounsaturation of fatty acids plays a role in hepatic lipotoxicity but also Myr inhibition exasperates lipoapoptosis through ceramide in-direct pathway. Using the techniques presented in this study, we can potentially investigate the mechanism of lipid metabolism and the heterogeneous development of NAFLD.
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47
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Nicu C, Pople J, Bonsell L, Bhogal R, Ansell DM, Paus R. A guide to studying human dermal adipocytes in situ. Exp Dermatol 2018; 27:589-602. [DOI: 10.1111/exd.13549] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Carina Nicu
- Centre for Dermatology Research; The University of Manchester; Manchester UK
- NIHR Manchester Biomedical Research Centre; Manchester Academic Health Science Centre; Manchester UK
| | | | - Laura Bonsell
- Centre for Dermatology Research; The University of Manchester; Manchester UK
- NIHR Manchester Biomedical Research Centre; Manchester Academic Health Science Centre; Manchester UK
| | | | - David M. Ansell
- Centre for Dermatology Research; The University of Manchester; Manchester UK
- NIHR Manchester Biomedical Research Centre; Manchester Academic Health Science Centre; Manchester UK
| | - Ralf Paus
- Centre for Dermatology Research; The University of Manchester; Manchester UK
- NIHR Manchester Biomedical Research Centre; Manchester Academic Health Science Centre; Manchester UK
- Department of Dermatology and Cutaneous Surgery; Miller School of Medicine; University of Miami; Miami FL USA
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48
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Cobbs A, Ballou K, Chen X, George J, Zhao X. Saturated fatty acids bound to albumin enhance osteopontin expression and cleavage in renal proximal tubular cells. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2018; 10:29-38. [PMID: 29593848 PMCID: PMC5871627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 02/25/2018] [Indexed: 06/08/2023]
Abstract
Osteopontin (OPN) is one of the proinflammatory cytokines upregulated in the kidneys of diabetic animals and patients with nephropathy. An increase in urinary albumin and albumin-bound fatty acids (FA) presents a proinflammatory environment to the proximal tubules in proteinuric kidney diseases including diabetic nephropathy. This study was designed to examine if FA overload could stimulate OPN expression and cleavage in renal tubule epithelial cells. OPN gene and protein expression was examined in the kidney of Zucker diabetic (ZD) rats and cultured proximal tubular cells exposed to either bovine serum albumin (BSA) or BSA conjugated with palmitic acid (PA), the most abundant saturated plasma FA. Real-time PCR analysis confirmed an upregulation of renal cortical OPN gene correlated with albuminuria and nephropathy progression in ZD rats at the age of 7-20 weeks. Immunofluorescence staining of kidney sections revealed a massive induction of OPN protein in albumin-overloaded proximal tubules of ZD rats. A significant increase in both intact and cleaved OPN proteins was further demonstrated in the diabetic kidney and urine samples, which was attenuated by antiproteinuric treatment with losartan, an angiotensin II receptor blocker. When exposed to fatty acid-free BSA, NRK-52E cells exhibited an increase in protein levels of full-length and cleaved OPN. Moreover, the increase in OPN fragments was greatly enhanced in the presence of PA (250-500 µM). Together, our results support a stimulatory effect of albumin and conjugated FA on OPN expression and cleavage in renal tubule epithelial cells. Thus, besides lowering albuminuria/proteinuria, mitigating circulating FAs may be an effective intervention for preventing and slowing down the progression of nephropathy associated with obesity and type 2 diabetes.
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Affiliation(s)
- Alyssa Cobbs
- Department of Physiology, Morehouse School of MedicineAtlanta 30310, GA, USA
| | - Kristopher Ballou
- Department of Physiology, Morehouse School of MedicineAtlanta 30310, GA, USA
| | - Xiaoming Chen
- Department of Physiology, Morehouse School of MedicineAtlanta 30310, GA, USA
| | - Jasmine George
- Department of Physiology, Morehouse School of MedicineAtlanta 30310, GA, USA
| | - Xueying Zhao
- Department of Physiology, Morehouse School of MedicineAtlanta 30310, GA, USA
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49
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Jackson KC, Tarpey MD, Valencia AP, Iñigo MR, Pratt SJ, Patteson DJ, McClung JM, Lovering RM, Thomson DM, Spangenburg EE. Induced Cre-mediated knockdown of Brca1 in skeletal muscle reduces mitochondrial respiration and prevents glucose intolerance in adult mice on a high-fat diet. FASEB J 2018; 32:3070-3084. [PMID: 29401626 DOI: 10.1096/fj.201700464r] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The breast cancer type 1 susceptibility protein (Brca1) is a regulator of DNA repair in mammary gland cells; however, recent cell culture evidence suggests that Brca1 influences other processes, including those in nonmammary cells. In this study, we sought to determine whether Brca1 is necessary for metabolic regulation of skeletal muscle using a novel in vivo mouse model. We developed an inducible skeletal muscle-specific Brca1knockout (BRCA1KOsmi) model to test whether Brca1 expression is necessary for maintenance of metabolic function of skeletal muscle when exposed to a high-fat diet (HFD). Our data demonstrated that deletion of Brca1 prevented HFD-induced alterations in glucose and insulin tolerance. Irrespective of diet, BRCA1KOsmi mice exhibited significantly lower ADP-stimulated complex I mitochondrial respiration rates compared to age-matched wild-type (WT) mice. The data show that Brca1 has the ability to localize to the mitochondria in skeletal muscle and that BRCA1KOsmi mice exhibit higher whole-body CO2 production, respiratory exchange ratio, and energy expenditure, compared with the WT mice. Our results demonstrate that loss of Brca1 in skeletal muscle leads to dysregulated metabolic function, characterized by decreased mitochondrial respiration. Thus, any condition that results in loss of Brca1 function could induce metabolic imbalance in skeletal muscle.-Jackson, K. C., Tarpey, M. D., Valencia, A. P., Iñigo, M. R., Pratt, S. J., Patteson, D. J., McClung, J. M., Lovering, R. M., Thomson, D. M., Spangenburg, E. E. Induced Cre-mediated knockdown of Brca1 in skeletal muscle reduces mitochondrial respiration and prevents glucose intolerance in adult mice on a high-fat diet.
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Affiliation(s)
- Kathryn C Jackson
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA
| | - Michael D Tarpey
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Ana P Valencia
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA
| | - Melissa R Iñigo
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA.,Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Stephen J Pratt
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Daniel J Patteson
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
| | - Joseph M McClung
- Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; and
| | - Richard M Lovering
- Department of Orthopaedics, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - David M Thomson
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA
| | - Espen E Spangenburg
- Department of Kinesiology, School of Public Health, University of Maryland, College Park, Maryland, USA.,Department of Physiology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.,East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina, USA; and
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50
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Dave T, Tilles AW, Vemula M. A Cell-Based Assay to Investigate Hypolipidemic Effects of Nonalcoholic Fatty Liver Disease Therapeutics. SLAS DISCOVERY 2017; 23:274-282. [PMID: 29132235 DOI: 10.1177/2472555217741077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the recent past, there has been a growing interest in developing nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) therapeutics. As a result, a need for in vitro cell models of human hepatic steatosis and high-throughput assays to measure intracellular lipid levels has arisen. To address this growing need, we optimized the conditions based on the current literature to fatten HepG2 hepatocytes by adding a mixture of saturated and unsaturated fatty acids (oleate/palmitate, 2:1 molar ratio) without inducing any overt cytotoxicity. Our results indicate that hepatocytes fatten in a concentration- (0.75-1.5 mM of fatty acids) and time-dependent manner, with a substantial increase in intracellular lipid levels seen within 6 h. Additionally, a method to quantify lipid levels in cells using a fluorescent reagent that is more sensitive than that in conventional assays and adaptable for high-throughput screening is presented. Lastly, the utility of the in vitro cell model and an assay based on AdipoRed to measure hypolipidemic effects of therapeutic drugs is demonstrated using fenofibrate, a molecule that was previously shown to lower lipid levels in the liver.
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