1
|
Tang Y, Majewska M, Leß B, Mehmeti I, Wollnitzke P, Semleit N, Levkau B, Saba JD, van Echten-Deckert G, Gurgul-Convey E. The fate of intracellular S1P regulates lipid droplet turnover and lipotoxicity in pancreatic beta-cells. J Lipid Res 2024; 65:100587. [PMID: 38950680 PMCID: PMC11345310 DOI: 10.1016/j.jlr.2024.100587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 06/07/2024] [Accepted: 06/22/2024] [Indexed: 07/03/2024] Open
Abstract
Lipotoxicity has been considered the main cause of pancreatic beta-cell failure during type 2 diabetes development. Lipid droplets (LD) are believed to regulate the beta-cell sensitivity to free fatty acids (FFA), but the underlying molecular mechanisms are largely unclear. Accumulating evidence points, however, to an important role of intracellular sphingosine-1-phosphate (S1P) metabolism in lipotoxicity-mediated disturbances of beta-cell function. In the present study, we compared the effects of an increased irreversible S1P degradation (S1P-lyase, SPL overexpression) with those associated with an enhanced S1P recycling (overexpression of S1P phosphatase 1, SGPP1) on LD formation and lipotoxicity in rat INS1E beta-cells. Interestingly, although both approaches led to a reduced S1P concentration, they had opposite effects on the susceptibility to FFA. Overexpression of SGPP1 prevented FFA-mediated caspase-3 activation by a mechanism involving an enhanced lipid storage capacity and prevention of oxidative stress. In contrast, SPL overexpression limited LD biogenesis, content, and size, while accelerating lipophagy. This was associated with FFA-induced hydrogen peroxide formation, mitochondrial fragmentation, and dysfunction, as well as ER stress. These changes coincided with the upregulation of proapoptotic ceramides but were independent of lipid peroxidation rate. Also in human EndoC-βH1 beta-cells, suppression of SPL with simultaneous overexpression of SGPP1 led to a similar and even more pronounced LD phenotype as that in INS1E-SGPP1 cells. Thus, intracellular S1P turnover significantly regulates LD content and size and influences beta-cell sensitivity to FFA.
Collapse
Affiliation(s)
- Yadi Tang
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Mariola Majewska
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Britta Leß
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Ilir Mehmeti
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Philipp Wollnitzke
- Institute of Molecular Medicine III, University Hospital Düsseldorf and Heinrich Heine University, Düsseldorf, Germany
| | - Nina Semleit
- Institute of Molecular Medicine III, University Hospital Düsseldorf and Heinrich Heine University, Düsseldorf, Germany
| | - Bodo Levkau
- Institute of Molecular Medicine III, University Hospital Düsseldorf and Heinrich Heine University, Düsseldorf, Germany
| | - Julie D Saba
- Division of Hematology/Oncology, Department of Pediatrics, University of California. San Francisco, Oakland, CA, USA
| | | | - Ewa Gurgul-Convey
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
| |
Collapse
|
2
|
Risi R, Vidal-Puig A, Bidault G. An adipocentric perspective of pancreatic lipotoxicity in diabetes pathogenesis. J Endocrinol 2024; 262:e230313. [PMID: 38642584 PMCID: PMC11227041 DOI: 10.1530/joe-23-0313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 04/16/2024] [Indexed: 04/22/2024]
Abstract
Obesity and diabetes represent two increasing and invalidating public health issues that often coexist. It is acknowledged that fat mass excess predisposes to insulin resistance and type 2 diabetes mellitus (T2D), with the increasing incidence of the two diseases significantly associated. Moreover, emerging evidence suggests that obesity might also accelerate the appearance of type 1 diabetes (T1D), which is now a relatively frequent comorbidity in patients with obesity. It is a common clinical finding that not all patients with obesity will develop diabetes at the same level of adiposity, with gender, genetic, and ethnic factors playing an important role in defining the timing of diabetes appearance. The adipose tissue (AT) expandability hypothesis explains this paradigm, indicating that the individual capacity to appropriately store energy surplus in the form of fat within the AT determines and prevents the toxic deposition of lipids in other organs, such as the pancreas. Thus, we posit that when the maximal storing capacity of AT is exceeded, individuals will develop T2D. In this review, we provide insight into mechanisms by which the AT controls pancreas lipid content and homeostasis in case of obesity to offer an adipocentric perspective of pancreatic lipotoxicity in the pathogenesis of diabetes. Moreover, we suggest that improving AT function is a valid therapeutic approach to fighting obesity-associated complications including diabetes.
Collapse
Affiliation(s)
- Renata Risi
- Department of Experimental Medicine, Sapienza University of Rome, Sapienza University of Rome, Rome, Italy
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| | - Antonio Vidal-Puig
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
- Cambridge University Nanjing Centre of Technology and Innovation, Nanjing, P. R. China
- Centro de Investigacion Principe Felipe, Valencia, Spain
| | - Guillaume Bidault
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge, UK
| |
Collapse
|
3
|
Chandrasekaran P, Weiskirchen S, Weiskirchen R. Perilipins: A family of five fat-droplet storing proteins that play a significant role in fat homeostasis. J Cell Biochem 2024; 125:e30579. [PMID: 38747370 DOI: 10.1002/jcb.30579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/18/2024] [Accepted: 04/30/2024] [Indexed: 06/12/2024]
Abstract
Lipid droplets are organelles with unique spherical structures. They consist of a hydrophobic neutral lipid core that varies depending on the cell type and tissue. These droplets are surrounded by phospholipid monolayers, along with heterogeneous proteins responsible for neutral lipid synthesis and metabolism. Additionally, there are specialized lipid droplet-associated surface proteins. Recent evidence suggests that proteins from the perilipin family (PLIN) are associated with the surface of lipid droplets and are involved in their formation. These proteins have specific roles in hepatic lipid droplet metabolism, such as protecting the lipid droplets from lipase action and maintaining a balance between lipid storage and utilization in specific cells. Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by the accumulation of lipid droplets in more than 5% of the hepatocytes. This accumulation can progress into metabolic dysfunction-associated steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The accumulation of hepatic lipid droplets in the liver is associated with the progression of MASLD and other diseases such as sarcopenic obesity. Therefore, it is crucial to understand the role of perilipins in this accumulation, as these proteins are key targets for developing novel therapeutic strategies. This comprehensive review aims to summarize the structure and characteristics of PLIN proteins, as well as their pathogenic role in the development of hepatic steatosis and fatty liver diseases.
Collapse
Affiliation(s)
| | - Sabine Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), Rheinisch-Westfälische Technische Hochschule (RWTH), University Hospital Aachen, Aachen, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), Rheinisch-Westfälische Technische Hochschule (RWTH), University Hospital Aachen, Aachen, Germany
| |
Collapse
|
4
|
Yin X, Dong L, Wang X, Qin Z, Ma Y, Ke X, Li Y, Wang Q, Mi Y, Lyu Q, Xu X, Zheng P, Tang Y. Perilipin 5 regulates hepatic stellate cell activation and high-fat diet-induced non-alcoholic fatty liver disease. Animal Model Exp Med 2024; 7:166-178. [PMID: 37202925 PMCID: PMC11079159 DOI: 10.1002/ame2.12327] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 04/21/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases globally. Hepatic stellate cells (HSCs) are the major effector cells of liver fibrosis. HSCs contain abundant lipid droplets (LDs) in their cytoplasm during quiescence. Perilipin 5 (PLIN 5) is a LD surface-associated protein that plays a crucial role in lipid homeostasis. However, little is known about the role of PLIN 5 in HSC activation. METHODS PLIN 5 was overexpressed in HSCs of Sprague-Dawley rats by lentivirus transfection. At the same time, PLIN 5 gene knockout mice were constructed and fed with a high-fat diet (HFD) for 20 weeks to study the role of PLIN 5 in NAFLD. The corresponding reagent kits were used to measure TG, GSH, Caspase 3 activity, ATP level, and mitochondrial DNA copy number. Metabolomic analysis of mice liver tissue metabolism was performed based on UPLC-MS/MS. AMPK, mitochondrial function, cell proliferation, and apoptosis-related genes and proteins were detected by western blotting and qPCR. RESULTS Overexpression of PLIN 5 in activated HSCs led to a decrease in ATP levels in mitochondria, inhibition of cell proliferation, and a significant increase in cell apoptosis through AMPK activation. In addition, compared with the HFD-fed C57BL/6J mice, PLIN 5 knockout mice fed with HFD showed reduced liver fat deposition, decreased LD abundance and size, and reduced liver fibrosis. CONCLUSION These findings highlight the unique regulatory role of PLIN 5 in HSCs and the role of PLIN 5 in the fibrosis process of NAFLD.
Collapse
Affiliation(s)
- Xuecui Yin
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Lin Dong
- Department of Pediatricsthe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Xiaohan Wang
- Department of Pediatricsthe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Zhenzhen Qin
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Yuying Ma
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Xiaofei Ke
- Department of Pediatricsthe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Ya Li
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Qingde Wang
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Yang Mi
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Quanjun Lyu
- Department of Clinical Nutritionthe First Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Xia Xu
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education of China, Co‐innovation Center of Henan Province for New drug R & D and Preclinical Safety, School of Pharmaceutical SciencesZhengzhou UniversityZhengzhouChina
| | - Pengyuan Zheng
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| | - Youcai Tang
- Department of Internal Medicinethe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
- Department of Pediatrics, Gastroenterology, Henan Key Laboratory of Rehabilitation Medicine, Henan Joint International Research Laboratory of Chronic Liver Injury and Henan Provincial Outstanding Overseas Scientists Chronic Liver Injury Studiothe Fifth Affiliated Hospital of Zhengzhou UniversityZhengzhouChina
| |
Collapse
|
5
|
Fernandes MF, Aristizabal-Henao JJ, Marvyn PM, M'Hiri I, Wiens MA, Hoang M, Sebastian M, Nachbar R, St-Pierre P, Diaguarachchige De Silva K, Wood GA, Joseph JW, Doucette CA, Marette A, Stark KD, Duncan RE. Renal tubule-specific Atgl deletion links kidney lipid metabolism to glucagon-like peptide 1 and insulin secretion independent of renal inflammation or lipotoxicity. Mol Metab 2024; 81:101887. [PMID: 38280449 PMCID: PMC10850971 DOI: 10.1016/j.molmet.2024.101887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 01/29/2024] Open
Abstract
OBJECTIVE Lipotoxic injury from renal lipid accumulation in obesity and type 2 diabetes (T2D) is implicated in associated kidney damage. However, models examining effects of renal ectopic lipid accumulation independent of obesity or T2D are lacking. We generated renal tubule-specific adipose triglyceride lipase knockout (RT-SAKO) mice to determine if this targeted triacylglycerol (TAG) over-storage affects glycemic control and kidney health. METHODS Male and female RT-SAKO mice and their control littermates were tested for changes in glycemic control at 10-12 and 16-18 weeks of age. Markers of kidney health and blood lipid and hormone concentrations were analyzed. Kidney and blood lysophosphatidic acid (LPA) levels were measured, and a role for LPA in mediating impaired glycemic control was evaluated using the LPA receptor 1/3 inhibitor Ki-16425. RESULTS All groups remained insulin sensitive, but 16- to 18-week-old male RT-SAKO mice became glucose intolerant, without developing kidney inflammation or fibrosis. Rather, these mice displayed lower circulating insulin and glucagon-like peptide 1 (GLP-1) levels. Impaired first-phase glucose-stimulated insulin secretion was detected and restored by Exendin-4. Kidney and blood LPA levels were elevated in older male but not female RT-SAKO mice, associated with increased kidney diacylglycerol kinase epsilon. Inhibition of LPA-mediated signaling restored serum GLP-1 levels, first-phase insulin secretion, and glucose tolerance. CONCLUSIONS TAG over-storage alone is insufficient to cause renal tubule lipotoxicity. This work is the first to show that endogenously derived LPA modulates GLP-1 levels in vivo, demonstrating a new mechanism of kidney-gut-pancreas crosstalk to regulate insulin secretion and glucose homeostasis.
Collapse
Affiliation(s)
- Maria F Fernandes
- Department of Kinesiology and Health Sciences, University of Waterloo, Ontario, Canada
| | | | - Phillip M Marvyn
- Department of Kinesiology and Health Sciences, University of Waterloo, Ontario, Canada
| | - Iman M'Hiri
- Department of Kinesiology and Health Sciences, University of Waterloo, Ontario, Canada
| | - Meghan A Wiens
- Department of Kinesiology and Health Sciences, University of Waterloo, Ontario, Canada
| | - Monica Hoang
- School of Pharmacy, University of Waterloo, Ontario, Canada
| | - Manuel Sebastian
- Max Rady College of Medicine, University of Manitoba, Manitoba, Canada
| | - Renato Nachbar
- Québec Heart and Lung Institute, Department of Medicine, Laval University, Québec, Canada
| | - Philippe St-Pierre
- Québec Heart and Lung Institute, Department of Medicine, Laval University, Québec, Canada
| | | | - Geoffrey A Wood
- Ontario Veterinary College, University of Guelph, Ontario, Canada
| | - Jamie W Joseph
- School of Pharmacy, University of Waterloo, Ontario, Canada
| | | | - André Marette
- Québec Heart and Lung Institute, Department of Medicine, Laval University, Québec, Canada
| | - Ken D Stark
- Department of Kinesiology and Health Sciences, University of Waterloo, Ontario, Canada
| | - Robin E Duncan
- Department of Kinesiology and Health Sciences, University of Waterloo, Ontario, Canada.
| |
Collapse
|
6
|
Thomas P, Gallagher MT, Da Silva Xavier G. Beta cell lipotoxicity in the development of type 2 diabetes: the need for species-specific understanding. Front Endocrinol (Lausanne) 2023; 14:1275835. [PMID: 38144558 PMCID: PMC10739424 DOI: 10.3389/fendo.2023.1275835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/13/2023] [Indexed: 12/26/2023] Open
Abstract
The propensity to develop type 2 diabetes (T2D) is known to have both environmental and hereditary components. In those with a genetic predisposition to T2D, it is widely believed that elevated concentrations of circulatory long-chain fatty acids (LC-FFA) significantly contribute towards the demise of insulin-producing pancreatic β-cells - the fundamental feature of the development of T2D. Over 25 years of research support that LC-FFA are deleterious to β-cells, through a process termed lipotoxicity. However, the work underpinning the theory of β-cell lipotoxicity is mostly based on rodent studies. Doubts have been raised as to whether lipotoxicity also occurs in humans. In this review, we examine the evidence, both in vivo and in vitro, for the pathogenic effects of LC-FFA on β-cell viability and function in humans, highlighting key species differences. In this way, we aim to uncover the role of lipotoxicity in the human pathogenesis of T2D and motivate the need for species-specific understanding.
Collapse
Affiliation(s)
- Patricia Thomas
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
- Institute for Metabolism and Systems Research, Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
| | - Meurig T. Gallagher
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
- Institute for Metabolism and Systems Research, Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
| | - Gabriela Da Silva Xavier
- Institute for Metabolism and Systems Research, Birmingham Medical School, University of Birmingham, Birmingham, United Kingdom
| |
Collapse
|
7
|
Morriseau TS, Doucette CA, Dolinsky VW. More than meets the islet: aligning nutrient and paracrine inputs with hormone secretion in health and disease. Am J Physiol Endocrinol Metab 2022; 322:E446-E463. [PMID: 35373587 DOI: 10.1152/ajpendo.00411.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pancreatic islet is responsive to an array of endocrine, paracrine, and nutritional inputs that adjust hormone secretion to ensure accurate control of glucose homeostasis. Although the mechanisms governing glucose-coupled insulin secretion have received the most attention, there is emerging evidence for a multitude of physiological signaling pathways and paracrine networks that collectively regulate insulin, glucagon, and somatostatin release. Moreover, the modulation of these pathways in conditions of glucotoxicity or lipotoxicity are areas of both growing interest and controversy. In this review, the contributions of external, intrinsic, and paracrine factors in pancreatic β-, α-, and δ-cell secretion across the full spectrum of physiological (i.e., fasting and fed) and pathophysiological (gluco- and lipotoxicity; diabetes) environments will be critically discussed.
Collapse
Affiliation(s)
- Taylor S Morriseau
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Christine A Doucette
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Vernon W Dolinsky
- Diabetes Research Envisioned and Accomplished in Manitoba (DREAM) Theme of the Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| |
Collapse
|
8
|
Plin5, a New Target in Diabetic Cardiomyopathy. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:2122856. [PMID: 35509833 PMCID: PMC9060988 DOI: 10.1155/2022/2122856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/14/2022] [Accepted: 04/06/2022] [Indexed: 02/07/2023]
Abstract
Abnormal lipid accumulation is commonly observed in diabetic cardiomyopathy (DC), which can create a lipotoxic microenvironment and damage cardiomyocytes. Lipid toxicity is an important pathogenic factor due to abnormal lipid accumulation in DC. As a lipid droplet (LD) decomposition barrier, Plin5 can protect LDs from lipase decomposition and regulate lipid metabolism, which is involved in the occurrence and development of cardiovascular diseases. In recent years, studies have shown that Plin5 expression is involved in the pathogenesis of DC lipid toxicity, such as oxidative stress, mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and insulin resistance (IR) and has become a key target of DC research. Therefore, understanding the relationship between Plin5 and DC progression as well as the mechanism of this process is crucial for developing new therapeutic approaches and exploring new therapeutic targets. This review is aimed at exploring the latest findings and roles of Plin5 in lipid metabolism and DC-related pathogenesis, to explore possible clinical intervention approaches.
Collapse
|
9
|
Plin5 Bidirectionally Regulates Lipid Metabolism in Oxidative Tissues. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:4594956. [PMID: 35401929 PMCID: PMC8989587 DOI: 10.1155/2022/4594956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 10/08/2021] [Accepted: 03/16/2022] [Indexed: 11/20/2022]
Abstract
Cytoplasmic lipid droplets (LDs) can store neutral lipids as an energy source when needed and also regulate the key metabolic processes of intracellular lipid accumulation, which is associated with several metabolic diseases. The perilipins (Plins) are a family of proteins that associate with the surface of LDs. As a member of Plins superfamily, perilipin 5 (Plin5) coats LDs in cardiomyocytes, which is significantly related to reactive oxygen species (ROS) production originated from mitochondria in the heart, consequently determining the progression of diabetic cardiomyopathy. Plin5 may play a bidirectional function in lipid metabolism which is in a state of dynamic balance. In the basic state, Plin5 inhibited the binding of comparative gene identification-58 (CGI-58) to adipose triglyceride lipase (ATGL) by binding CGI-58, thus inhibiting lipolysis. However, when the body is under stress (such as cold, fasting, exercise, and other stimuli), protein kinase A (PKA) phosphorylates and activates Plin5, which then causes Plin5 to release the binding site of CGI-58 and ATGL, prompting CGI-58 to bind to ATGL and activate ATGL activity, thus accelerating the lipolysis process, revealing the indispensable role of Plin5 in lipid turnover. Here, the purpose of this review is to summarize the present understanding of the bidirectional regulation role of Plin5 in oxidative tissues and to reveal its potential role in diabetic cardiomyopathy protection.
Collapse
|
10
|
Tong X, Liu S, Stein R, Imai Y. Lipid Droplets' Role in the Regulation of β-Cell Function and β-Cell Demise in Type 2 Diabetes. Endocrinology 2022; 163:6516108. [PMID: 35086144 PMCID: PMC8826878 DOI: 10.1210/endocr/bqac007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Indexed: 01/29/2023]
Abstract
During development of type 2 diabetes (T2D), excessive nutritional load is thought to expose pancreatic islets to toxic effects of lipids and reduce β-cell function and mass. However, lipids also play a positive role in cellular metabolism and function. Thus, proper trafficking of lipids is critical for β cells to maximize the beneficial effects of these molecules while preventing their toxic effects. Lipid droplets (LDs) are organelles that play an important role in the storage and trafficking of lipids. In this review, we summarize the discovery of LDs in pancreatic β cells, LD lifecycle, and the effect of LD catabolism on β-cell insulin secretion. We discuss factors affecting LD formation such as age, cell type, species, and nutrient availability. We then outline published studies targeting critical LD regulators, primarily in rat and human β-cell models, to understand the molecular effect of LD formation and degradation on β-cell function and health. Furthermore, based on the abnormal LD accumulation observed in human T2D islets, we discuss the possible role of LDs during the development of β-cell failure in T2D. Current knowledge indicates that proper formation and clearance of LDs are critical to normal insulin secretion, endoplasmic reticulum homeostasis, and mitochondrial integrity in β cells. However, it remains unclear whether LDs positively or negatively affect human β-cell demise in T2D. Thus, we discuss possible research directions to address the knowledge gap regarding the role of LDs in β-cell failure.
Collapse
Affiliation(s)
- Xin Tong
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Siming Liu
- Department of Internal Medicine Carver College of Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
| | - Roland Stein
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, Tennessee 37232, USA
| | - Yumi Imai
- Department of Internal Medicine Carver College of Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa 52242, USA
- Iowa City Veterans Affairs Medical Center, Iowa City, Iowa 52246, USA
- Correspondence: Yumi Imai, MD, Department of Internal Medicine Carver College of Medicine, Fraternal Order of Eagles Diabetes Research Center, University of Iowa, 200 Hawkins Dr, PBDB Rm 3318, Iowa City, IA 52242, USA.
| |
Collapse
|
11
|
Hello from the other side: Membrane contact of lipid droplets with other organelles and subsequent functional implications. Prog Lipid Res 2021; 85:101141. [PMID: 34793861 DOI: 10.1016/j.plipres.2021.101141] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 02/06/2023]
Abstract
Lipid droplets (LDs) are ubiquitous organelles that play crucial roles in response to physiological and environmental cues. The identification of several neutral lipid synthesizing and regulatory protein complexes have propelled significant advance on the mechanisms of LD biogenesis in the endoplasmic reticulum (ER). Increasing evidence suggests that distinct proteins and regulatory factors, which localize to membrane contact sites (MCS), are involved not only in interorganellar lipid exchange and transport, but also function in other important cellular processes, including autophagy, mitochondrial dynamics and inheritance, ion signaling and inter-regulation of these MCS. More and more tethers and molecular determinants are associated to MCS and to a diversity of cellular and pathophysiological processes, demonstrating the dynamics and importance of these junctions in health and disease. The conjugation of lipids with proteins in supramolecular complexes is known to be paramount for many biological processes, namely membrane biosynthesis, cell homeostasis, regulation of organelle division and biogenesis, and cell growth. Ultimately, this physical organization allows the contact sites to function as crucial metabolic hubs that control the occurrence of chemical reactions. This leads to biochemical and metabolite compartmentalization for the purposes of energetic efficiency and cellular homeostasis. In this review, we will focus on the structural and functional aspects of LD-organelle interactions and how they ensure signaling exchange and metabolites transfer between organelles.
Collapse
|
12
|
Zhang X, Su L, Sun K. Expression status and prognostic value of the perilipin family of genes in breast cancer. Am J Transl Res 2021; 13:4450-4463. [PMID: 34150026 PMCID: PMC8205812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND The Perilipin (PLIN) family of genes were previously shown to be involved in the formation and degradation of Lipid Droplets (LDs). In addition, they may play important roles in the development and progression of breast cancer. However, the prognostic value of PLIN family members in breast cancer patients remains unclear. METHODS Mutations and copy number alterations of PLIN family genes in breast cancer were examined using the cBioportal for Cancer Genomics. In addition, the expression patterns of PLIN family genes were explored using the UCSC Xena online tool. Finally, the Kaplan-Meier Plotter was used to investigate the prognostic value of PLIN family genes in breast cancer. RESULTS The findings revealed a low frequency of genetic alterations and amplification was the most frequent change in the PLIN family genes. Additionally, there was an increase in the expression of Perilipin 3 (PLIN3) in breast cancer tissues compared to normal breast tissues. However, expression of the other genes in the PLIN family was significantly lower in breast cancer tissues compared to normal breast tissues. Moreover, there was an increase in the expression levels of Perilipin 1 (PLIN1), PLIN3, Perilipin 4 (PLIN4) and Perilipin 5 (PLIN5) in the luminal A and luminal B subgroups. On the other hand, the expression of Perilipin 2 (PLIN2) was elevated in the human epidermal growth factor receptor 2 (HER2) positive and basal-like subgroups. Furthermore, Kaplan-Meier Plotter analysis demonstrated that high expression of PLIN1 might predict a longer Overall Survival (OS) in patients with breast cancer while overexpression of PLIN2 indicated poor OS of breast cancer patients. CONCLUSION The findings from this study indicated that genes in the PLIN family were aberrantly expressed in breast cancer and may serve as novel therapeutic targets as well as prognostic biomarkers for the disease.
Collapse
Affiliation(s)
- Xuede Zhang
- Department of Hematology and Oncology, Beilun District People’s HospitalNingbo, Zhejiang, China
| | - Lei Su
- Department of Oncology, Zhangqiu District People’s HospitalJinan, Shandong, China
| | - Kai Sun
- Department of Oncology, Liuzhou People’s HospitalLiuzhou 545001, Guangxi Zhuang Autonomous Region, China
| |
Collapse
|
13
|
Mitrofanova A, Burke G, Merscher S, Fornoni A. New insights into renal lipid dysmetabolism in diabetic kidney disease. World J Diabetes 2021; 12:524-540. [PMID: 33995842 PMCID: PMC8107981 DOI: 10.4239/wjd.v12.i5.524] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 03/31/2021] [Accepted: 04/26/2021] [Indexed: 02/06/2023] Open
Abstract
Lipid dysmetabolism is one of the main features of diabetes mellitus and manifests by dyslipidemia as well as the ectopic accumulation of lipids in various tissues and organs, including the kidney. Research suggests that impaired cholesterol metabolism, increased lipid uptake or synthesis, increased fatty acid oxidation, lipid droplet accumulation and an imbalance in biologically active sphingolipids (such as ceramide, ceramide-1-phosphate and sphingosine-1-phosphate) contribute to the development of diabetic kidney disease (DKD). Currently, the literature suggests that both quality and quantity of lipids are associated with DKD and contribute to increased reactive oxygen species production, oxidative stress, inflammation, or cell death. Therefore, control of renal lipid dysmetabolism is a very important therapeutic goal, which needs to be archived. This article will review some of the recent advances leading to a better understanding of the mechanisms of dyslipidemia and the role of particular lipids and sphingolipids in DKD.
Collapse
Affiliation(s)
- Alla Mitrofanova
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
| | - George Burke
- Department of Surgery, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
- Diabetes Research Institute, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
| | - Sandra Merscher
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
| | - Alessia Fornoni
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL 33136, United States
| |
Collapse
|
14
|
Mishra A, Liu S, Promes J, Harata M, Sivitz W, Fink B, Bhardwaj G, O'Neill BT, Kang C, Sah R, Strack S, Stephens S, King T, Jackson L, Greenberg AS, Anokye-Danso F, Ahima RS, Ankrum J, Imai Y. Perilipin 2 downregulation in β cells impairs insulin secretion under nutritional stress and damages mitochondria. JCI Insight 2021; 6:144341. [PMID: 33784258 PMCID: PMC8262280 DOI: 10.1172/jci.insight.144341] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/24/2021] [Indexed: 12/15/2022] Open
Abstract
Perilipin 2 (PLIN2) is a lipid droplet (LD) protein in β cells that increases under nutritional stress. Downregulation of PLIN2 is often sufficient to reduce LD accumulation. To determine whether PLIN2 positively or negatively affects β cell function under nutritional stress, PLIN2 was downregulated in mouse β cells, INS1 cells, and human islet cells. β Cell–specific deletion of PLIN2 in mice on a high-fat diet reduced glucose-stimulated insulin secretion (GSIS) in vivo and in vitro. Downregulation of PLIN2 in INS1 cells blunted GSIS after 24-hour incubation with 0.2 mM palmitic acid. Downregulation of PLIN2 in human pseudoislets cultured at 5.6 mM glucose impaired both phases of GSIS, indicating that PLIN2 is critical for GSIS. Downregulation of PLIN2 decreased specific OXPHOS proteins in all 3 models and reduced oxygen consumption rates in INS1 cells and mouse islets. Moreover, we found that PLIN2-deficient INS1 cells increased the distribution of a fluorescent oleic acid analog to mitochondria and showed signs of mitochondrial stress, as indicated by susceptibility to fragmentation and alterations of acyl-carnitines and glucose metabolites. Collectively, PLIN2 in β cells has an important role in preserving insulin secretion, β cell metabolism, and mitochondrial function under nutritional stress.
Collapse
Affiliation(s)
- Akansha Mishra
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Siming Liu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Joseph Promes
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Mikako Harata
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - William Sivitz
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Brian Fink
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Gourav Bhardwaj
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Brian T O'Neill
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Iowa City Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Chen Kang
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rajan Sah
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, USA
| | - Samuel Stephens
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| | - Timothy King
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Laura Jackson
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia, USA
| | - Andrew S Greenberg
- Obesity and Metabolism Laboratory, Jean Mayer United States Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts, USA
| | | | - Rexford S Ahima
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - James Ankrum
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA.,Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Yumi Imai
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, USA
| |
Collapse
|
15
|
Al-Mrabeh A. β-Cell Dysfunction, Hepatic Lipid Metabolism, and Cardiovascular Health in Type 2 Diabetes: New Directions of Research and Novel Therapeutic Strategies. Biomedicines 2021; 9:226. [PMID: 33672162 PMCID: PMC7927138 DOI: 10.3390/biomedicines9020226] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/09/2021] [Accepted: 02/17/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiovascular disease (CVD) remains a major problem for people with type 2 diabetes mellitus (T2DM), and dyslipidemia is one of the main drivers for both metabolic diseases. In this review, the major pathophysiological and molecular mechanisms of β-cell dysfunction and recovery in T2DM are discussed in the context of abnormal hepatic lipid metabolism and cardiovascular health. (i) In normal health, continuous exposure of the pancreas to nutrient stimulus increases the demand on β-cells. In the long term, this will not only stress β-cells and decrease their insulin secretory capacity, but also will blunt the cellular response to insulin. (ii) At the pre-diabetes stage, β-cells compensate for insulin resistance through hypersecretion of insulin. This increases the metabolic burden on the stressed β-cells and changes hepatic lipoprotein metabolism and adipose tissue function. (iii) If this lipotoxic hyperinsulinemic environment is not removed, β-cells start to lose function, and CVD risk rises due to lower lipoprotein clearance. (iv) Once developed, T2DM can be reversed by weight loss, a process described recently as remission. However, the precise mechanism(s) by which calorie restriction causes normalization of lipoprotein metabolism and restores β-cell function are not fully established. Understanding the pathophysiological and molecular basis of β-cell failure and recovery during remission is critical to reduce β-cell burden and loss of function. The aim of this review is to highlight the link between lipoprotein export and lipid-driven β-cell dysfunction in T2DM and how this is related to cardiovascular health. A second aim is to understand the mechanisms of β-cell recovery after weight loss, and to explore new areas of research for developing more targeted future therapies to prevent T2DM and the associated CVD events.
Collapse
Affiliation(s)
- Ahmad Al-Mrabeh
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| |
Collapse
|
16
|
You Q, Peng Q, Yu Z, Jin H, Zhang J, Sun W, Huang Y. Plasma lipidomic analysis of sphingolipids in patients with large artery atherosclerosis cerebrovascular disease and cerebral small vessel disease. Biosci Rep 2020; 40:BSR20201519. [PMID: 32830858 PMCID: PMC7502657 DOI: 10.1042/bsr20201519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/11/2020] [Accepted: 08/19/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Sphingolipids mainly consist of ceramides (Cer), sphingomyelins (SM) and glycosphingolipids. Sphingolipids are related with coronary heart disease and metabolic disease, but there're few studies about cerebrovascular disease. The purpose was to detect sphingolipids in plasma of patients with large artery atherosclerosis (LAA) cerebrovascular disease and cerebral small vessel disease (CSVD) to explore the similarities and differences of pathogenesis of the two subtypes. METHODS 20 patients with LAA cerebrovascular disease, 20 patients with age-related CSVD, 10 patients with Fabry disease and 14 controls were enrolled from October 2017 to January 2019. Ultra-high performance liquid chromatography-quadruple-time-of-flight mass spectrometry/mass spectrometry was used to determine sphingolipids. Univariate combined with multivariate analysis was used for comparison. Receiver operating characteristic curves were used to determine sensitivities and specificities. RESULTS 276 sphingolipids were detected, including 39 Cer, 3 ceramide phosphates, 72 glycosphingolipids and 162 SM. (1) Cer (d36:3), Cer (d34:2), Cer (d38:6), Cer (d36:4) and Cer (d16:0/18:1) were increased in LAA; SM (d34:1), Cer (d34:2), Cer (d36:4), Cer (d16:0/18:1), Cer (d38:6), Cer (d36:3) and Cer (d32:0) were increased in age-related CSVD. (2) Cer (d36:4) and SM (d34:1) were increased in age-related CSVD compared with LAA. (3) Total trihexosyl ceramides were increased in Fabry group compared with control (P<0.05); SM (d34:1) was increased in Fabry group. CONCLUSIONS Ceramides are increased in both LAA and age-related CSVD, which may be related to similar risk factors and pathophysiological process of arteriosclerosis; SM is increased in both age-related CSVD and Fabry disease, suggesting that increased SM may be associated with CSVD. Glycosphingolipids, trihexosylceramides in particular, are increased in Fabry disease.
Collapse
Affiliation(s)
- Qian You
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| | - Qing Peng
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| | - Zemou Yu
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| | - Haiqiang Jin
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| | - Jing Zhang
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| | - Wei Sun
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| | - Yining Huang
- Department of Neurology, Peking University First Hospital 100034, Beijing, China
| |
Collapse
|
17
|
Liu S, Promes JA, Harata M, Mishra A, Stephens SB, Taylor EB, Burand AJ, Sivitz WI, Fink BD, Ankrum JA, Imai Y. Adipose Triglyceride Lipase Is a Key Lipase for the Mobilization of Lipid Droplets in Human β-Cells and Critical for the Maintenance of Syntaxin 1a Levels in β-Cells. Diabetes 2020; 69:1178-1192. [PMID: 32312867 PMCID: PMC7243295 DOI: 10.2337/db19-0951] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 02/28/2020] [Indexed: 12/11/2022]
Abstract
Lipid droplets (LDs) are frequently increased when excessive lipid accumulation leads to cellular dysfunction. Distinct from mouse β-cells, LDs are prominent in human β-cells. However, the regulation of LD mobilization (lipolysis) in human β-cells remains unclear. We found that glucose increases lipolysis in nondiabetic human islets but not in islets in patients with type 2 diabetes (T2D), indicating dysregulation of lipolysis in T2D islets. Silencing adipose triglyceride lipase (ATGL) in human pseudoislets with shRNA targeting ATGL (shATGL) increased triglycerides (TGs) and the number and size of LDs, indicating that ATGL is the principal lipase in human β-cells. In shATGL pseudoislets, biphasic glucose-stimulated insulin secretion (GSIS), and insulin secretion to 3-isobutyl-1-methylxanthine and KCl were all reduced without altering oxygen consumption rate compared with scramble control. Like human islets, INS1 cells showed visible LDs, glucose-responsive lipolysis, and impairment of GSIS after ATGL silencing. ATGL-deficient INS1 cells and human pseudoislets showed reduced SNARE protein syntaxin 1a (STX1A), a key SNARE component. Proteasomal degradation of Stx1a was accelerated likely through reduced palmitoylation in ATGL-deficient INS1 cells. Therefore, ATGL is responsible for LD mobilization in human β-cells and supports insulin secretion by stabilizing STX1A. The dysregulated lipolysis may contribute to LD accumulation and β-cell dysfunction in T2D islets.
Collapse
Affiliation(s)
- Siming Liu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Joseph A Promes
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Mikako Harata
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Akansha Mishra
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Samuel B Stephens
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Eric B Taylor
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Anthony J Burand
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA
| | - William I Sivitz
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - Brian D Fink
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| | - James A Ankrum
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Roy J. Carver Department of Biomedical Engineering, University of Iowa, Iowa City, IA
| | - Yumi Imai
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
| |
Collapse
|
18
|
The biology of lipid droplet-bound mitochondria. Semin Cell Dev Biol 2020; 108:55-64. [PMID: 32446655 DOI: 10.1016/j.semcdb.2020.04.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/17/2020] [Accepted: 04/18/2020] [Indexed: 12/12/2022]
Abstract
Proper regulation of cellular lipid storage and oxidation is indispensable for the maintenance of cellular energy homeostasis and health. Mitochondrial function has been shown to be a main determinant of functional lipid storage and oxidation, which is of particular interest for the adipose tissue, as it is the main site of triacylglyceride storage in lipid droplets (LDs). Recent studies have identified a subpopulation of mitochondria attached to LDs, peridroplet mitochondria (PDM) that can be separated from cytoplasmic mitochondria (CM) by centrifugation. PDM have distinct bioenergetics, proteome, cristae organization and dynamics that support LD build-up, however their role in adipose tissue biology remains largely unexplored. Therefore, understanding the molecular basis of LD homeostasis and their relationship to mitochondrial function and attachment in adipocytes is of major importance.
Collapse
|
19
|
Tong X, Dai C, Walker JT, Nair GG, Kennedy A, Carr RM, Hebrok M, Powers AC, Stein R. Lipid Droplet Accumulation in Human Pancreatic Islets Is Dependent On Both Donor Age and Health. Diabetes 2020; 69:342-354. [PMID: 31836690 PMCID: PMC7034188 DOI: 10.2337/db19-0281] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 12/08/2019] [Indexed: 12/13/2022]
Abstract
Human but not mouse islets transplanted into immunodeficient NSG mice effectively accumulate lipid droplets (LDs). Because chronic lipid exposure is associated with islet β-cell dysfunction, we investigated LD accumulation in the intact human and mouse pancreas over a range of ages and states of diabetes. Very few LDs were found in normal human juvenile pancreatic acinar and islet cells, with numbers subsequently increasing throughout adulthood. While accumulation appeared evenly distributed in postjuvenile acinar and islet cells in donors without diabetes, LDs were enriched in islet α- and β-cells from donors with type 2 diabetes (T2D). LDs were also found in the islet β-like cells produced from human embryonic cell-derived β-cell clusters. In contrast, LD accumulation was nearly undetectable in the adult rodent pancreas, even in hyperglycemic and hyperlipidemic models or 1.5-year-old mice. Taken together, there appear to be significant differences in pancreas islet cell lipid handling between species, and the human juvenile and adult cell populations. Moreover, our results suggest that LD enrichment could be impactful to T2D islet cell function.
Collapse
Affiliation(s)
- Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Chunhua Dai
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt, University Medical Center, Nashville, TN
| | - John T Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Gopika G Nair
- Diabetes Center, Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Arion Kennedy
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC
| | - Rotonya M Carr
- Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA
| | - Matthias Hebrok
- Diabetes Center, Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Vanderbilt, University Medical Center, Nashville, TN
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| |
Collapse
|
20
|
Zhang E, Cui W, Lopresti M, Mashek MT, Najt CP, Hu H, Mashek DG. Hepatic PLIN5 signals via SIRT1 to promote autophagy and prevent inflammation during fasting. J Lipid Res 2020; 61:338-350. [PMID: 31932301 DOI: 10.1194/jlr.ra119000336] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/09/2020] [Indexed: 01/04/2023] Open
Abstract
Lipid droplets (LDs) are energy-storage organelles that are coated with hundreds of proteins, including members of the perilipin (PLIN) family. PLIN5 is highly expressed in oxidative tissues, including the liver, and is thought to play a key role in uncoupling LD accumulation from lipotoxicity; however, the mechanisms behind this action are incompletely defined. We investigated the role of hepatic PLIN5 in inflammation and lipotoxicity in a murine model under both fasting and refeeding conditions and in hepatocyte cultures. PLIN5 ablation with antisense oligonucleotides triggered a pro-inflammatory response in livers from mice only under fasting conditions. Similarly, PLIN5 mitigated lipopolysaccharide- or palmitic acid-induced inflammatory responses in hepatocytes. During fasting, PLIN5 was also required for the induction of autophagy, which contributed to its anti-inflammatory effects. The ability of PLIN5 to promote autophagy and prevent inflammation were dependent upon signaling through sirtuin 1 (SIRT1), which is known to be activated in response to nuclear PLIN5 under fasting conditions. Taken together, these data show that PLIN5 signals via SIRT1 to promote autophagy and prevent FA-induced inflammation as a means to maintain hepatocyte homeostasis during periods of fasting and FA mobilization.
Collapse
Affiliation(s)
- Enxiang Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China.,Departments of Biochemistry, Molecular Biology, and Biophysics Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN
| | - Wenqi Cui
- Departments of Biochemistry, Molecular Biology, and Biophysics Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN
| | - Michael Lopresti
- Departments of Biochemistry, Molecular Biology, and Biophysics Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN
| | - Mara T Mashek
- Departments of Biochemistry, Molecular Biology, and Biophysics Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN
| | - Charles P Najt
- Departments of Biochemistry, Molecular Biology, and Biophysics Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN
| | - Hongbo Hu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, People's Republic of China
| | - Douglas G Mashek
- Departments of Biochemistry, Molecular Biology, and Biophysics Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN .,Medicine , Division of Diabetes, Endocrinology, and Metabolism, University of Minnesota, Minneapolis, MN
| |
Collapse
|
21
|
Zhu Y, Ren C, Zhang M, Zhong Y. Perilipin 5 Reduces Oxidative Damage Associated With Lipotoxicity by Activating the PI3K/ERK-Mediated Nrf2-ARE Signaling Pathway in INS-1 Pancreatic β-Cells. Front Endocrinol (Lausanne) 2020; 11:166. [PMID: 32296390 PMCID: PMC7136399 DOI: 10.3389/fendo.2020.00166] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/09/2020] [Indexed: 12/16/2022] Open
Abstract
Oxidative stress induced by free fatty acid overload in pancreatic β-cells is a potential contributory factor to dysfunction of insulin secretion and apoptotic cell death. Perilipin 5 (Plin5) has been reported to ameliorate oxidative stress-mediated damage in non-insulin-secreting tissues. We tested the hypothesis that Plin5 plays a similar role in pancreatic β-cells, which are extremely sensitive to oxidative stress. Here, our in vitro data showed that Plin5-mediated alleviation of palmitate-triggered apoptosis involves the mitochondrial pathway. And the protective role of Plin5 on β-cells was partially dependent on its modulation in oxidative stress. Upregulation of Plin5 in INS-1 cells decreased reactive oxygen species production, enhanced cellular glutathione levels, and induced expression of antioxidant enzymes glutamate-cysteine ligase catalytic subunit and heme oxygenase-1. However, knocking out of Plin5 abolished all of these beneficial effects. Furthermore, by using the O2- scavenger MnTMPyP, we verified that altering Plin5 expression impacted lipotoxic cell death partially via modulating oxidative stress. Mechanistic experiments revealed that Plin5 induced Nrf2-ARE system, a master regulator in the cellular adaptive response to oxidative stress, by activating PI3K/Akt and ERK signal pathways, contributing to the increase of antioxidant defense and consequently improving β-cell function and survival in the presence of lipotoxic oxidative stress. Overall, our findings indicate that Plin5 abrogates oxidative damage in INS-1 β-cells during lipotoxic stress partially through the enhancement of antioxidant defense involving the PI3K/Akt and ERK mediated Nrf2-ARE system.
Collapse
Affiliation(s)
- Yunxia Zhu
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
- *Correspondence: Yunxia Zhu
| | - Chenxi Ren
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Mingliang Zhang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| | - Yuan Zhong
- Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China
| |
Collapse
|
22
|
Zhu Y, Zhang X, Zhang L, Zhang M, Li L, Luo D, Zhong Y. Perilipin5 protects against lipotoxicity and alleviates endoplasmic reticulum stress in pancreatic β-cells. Nutr Metab (Lond) 2019; 16:50. [PMID: 31384284 PMCID: PMC6668071 DOI: 10.1186/s12986-019-0375-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 07/19/2019] [Indexed: 12/27/2022] Open
Abstract
Background Chronic exposure of pancreatic β-cells to excess free fatty acids is thought to contribute to type 2 diabetes pathogenesis in obesity by impairing β-cell function and even leading to apoptosis. In β-cells, lipid droplet-associated protein perilipin 5 (PLIN5) has been shown to enhance insulin secretion by regulating intracellular lipid metabolism; the roles of PLIN5 in response to lipotoxicity remain poorly understood. Methods INS-1 β-cells were transfected with PLIN5-overexpression adenovirus (Ad-PLIN5) and treated with palmitate. C57BL/6 J male mice were fed with high fat diet and tail intravenous injected with adeno-associated virus overexpressing PLIN5 (AAV-PLIN5) in β-cells. Results Our data showed that palmitate and PPAR agonists including WY14643 (PPARα), GW501516 (PPARβ/δ), rosiglitazone (PPARγ) in vitro all induced PLIN5 expression in INS-1 cells. Under palmitate overload, although upregulating PLIN5 promoted lipid droplet storage, it alleviated lipotoxicity in INS-1 β-cells with improved cell viability, cell apoptosis and β-cell function. The protection role of PLIN5 in β-cell function observed in cell experiments were further verified in in vivo study indicated by mitigated glucose intolerance in high fat diet fed mice with β-cell-specific overexpression of PLIN5. Mechanistic experiments revealed that enhanced FAO induced by elevation of PLIN5, followed by decreased ER stress may be a major mechanism responsible for alleviation of lipotoxicity observed in the present study. Conclusions Our finding substantiated the important role of PLIN5 in protection against lipotoxicity in β-cells. Electronic supplementary material The online version of this article (10.1186/s12986-019-0375-2) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Yunxia Zhu
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| | - Xiaoyan Zhang
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| | - Li Zhang
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| | - Mingliang Zhang
- 2Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233 China
| | - Ling Li
- 3Department of Endocrinology, Tongji Hospital, Tongji University School of Medicine, Shanghai, 200065 China
| | - Deng Luo
- 4Department of Endocrinology, Renmin Hospital of Wuhan University, Wuhan, 430060 China
| | - Yuan Zhong
- 1Department of Geriatrics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Road, Shanghai, 200233 China
| |
Collapse
|
23
|
Imai Y, Cousins RS, Liu S, Phelps BM, Promes JA. Connecting pancreatic islet lipid metabolism with insulin secretion and the development of type 2 diabetes. Ann N Y Acad Sci 2019; 1461:53-72. [PMID: 30937918 DOI: 10.1111/nyas.14037] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/24/2019] [Accepted: 01/30/2019] [Indexed: 02/06/2023]
Abstract
Obesity is the major contributing factor for the increased prevalence of type 2 diabetes (T2D) in recent years. Sustained positive influx of lipids is considered to be a precipitating factor for beta cell dysfunction and serves as a connection between obesity and T2D. Importantly, fatty acids (FA), a key building block of lipids, are a double-edged sword for beta cells. FA acutely increase glucose-stimulated insulin secretion through cell-surface receptor and intracellular pathways. However, chronic exposure to FA, combined with elevated glucose, impair the viability and function of beta cells in vitro and in animal models of obesity (glucolipotoxicity), providing an experimental basis for the propensity of beta cell demise under obesity in humans. To better understand the two-sided relationship between lipids and beta cells, we present a current view of acute and chronic handling of lipids by beta cells and implications for beta cell function and health. We also discuss an emerging role for lipid droplets (LD) in the dynamic regulation of lipid metabolism in beta cells and insulin secretion, along with a potential role for LD under nutritional stress in beta cells, and incorporate recent advancement in the field of lipid droplet biology.
Collapse
Affiliation(s)
- Yumi Imai
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| | - Ryan S Cousins
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia
| | - Siming Liu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| | - Brian M Phelps
- Department of Internal Medicine, Eastern Virginia Medical School, Norfolk, Virginia
| | - Joseph A Promes
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| |
Collapse
|
24
|
Ji J, Petropavlovskaia M, Khatchadourian A, Patapas J, Makhlin J, Rosenberg L, Maysinger D. Type 2 diabetes is associated with suppression of autophagy and lipid accumulation in β-cells. J Cell Mol Med 2019; 23:2890-2900. [PMID: 30710421 PMCID: PMC6433726 DOI: 10.1111/jcmm.14172] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/14/2018] [Accepted: 12/29/2018] [Indexed: 01/05/2023] Open
Abstract
Both type 2 diabetes (T2D) and obesity are characterized by excessive hyperlipidaemia and subsequent lipid droplet (LD) accumulation in adipose tissue. To investigate whether LDs also accumulate in β-cells of T2D patients, we assessed the expression of PLIN2, a LD-associated protein, in non-diabetic (ND) and T2D pancreata. We observed an up-regulation of PLIN2 mRNA and protein in β-cells of T2D patients, along with significant changes in the expression of lipid metabolism, apoptosis and oxidative stress genes. The increased LD buildup in T2D β-cells was accompanied by inhibition of nuclear translocation of TFEB, a master regulator of autophagy and by down-regulation of lysosomal biomarker LAMP2. To investigate whether LD accumulation and autophagy were influenced by diabetic conditions, we used rat INS-1 cells to model the effects of hyperglycaemia and hyperlipidaemia on autophagy and metabolic gene expression. Consistent with human tissue, both LD formation and PLIN2 expression were enhanced in INS-1 cells under hyperglycaemia, whereas TFEB activation and autophagy gene expression were significantly reduced. Collectively, these results suggest that lipid clearance and overall homeostasis is markedly disrupted in β-cells under hyperglycaemic conditions and interventions ameliorating lipid clearance could be beneficial in reducing functional impairments in islets caused by glucolipotoxicity.
Collapse
Affiliation(s)
- Jeff Ji
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | | | - Armen Khatchadourian
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| | - Jason Patapas
- Department of Surgery, McGill University, Montreal, QC, Canada
| | - Julia Makhlin
- Department of Surgery, McGill University, Montreal, QC, Canada
| | | | - Dusica Maysinger
- Department of Pharmacology and Therapeutics, McGill University, Montreal, QC, Canada
| |
Collapse
|
25
|
Liu Y, Xu S, Zhang C, Zhu X, Hammad MA, Zhang X, Christian M, Zhang H, Liu P. Hydroxysteroid dehydrogenase family proteins on lipid droplets through bacteria, C. elegans, and mammals. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:881-894. [DOI: 10.1016/j.bbalip.2018.04.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/18/2018] [Accepted: 04/21/2018] [Indexed: 02/08/2023]
|
26
|
Chen M, Zhang J, Sampieri K, Clohessy JG, Mendez L, Gonzalez-Billalabeitia E, Liu XS, Lee YR, Fung J, Katon JM, Menon AV, Webster KA, Ng C, Palumbieri MD, Diolombi MS, Breitkopf SB, Teruya-Feldstein J, Signoretti S, Bronson RT, Asara JM, Castillo-Martin M, Cordon-Cardo C, Pandolfi PP. An aberrant SREBP-dependent lipogenic program promotes metastatic prostate cancer. Nat Genet 2018; 50:206-218. [PMID: 29335545 DOI: 10.1038/s41588-017-0027-2] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/01/2017] [Indexed: 12/15/2022]
Abstract
Lipids, either endogenously synthesized or exogenous, have been linked to human cancer. Here we found that PML is frequently co-deleted with PTEN in metastatic human prostate cancer (CaP). We demonstrated that conditional inactivation of Pml in the mouse prostate morphs indolent Pten-null tumors into lethal metastatic disease. We identified MAPK reactivation, subsequent hyperactivation of an aberrant SREBP prometastatic lipogenic program, and a distinctive lipidomic profile as key characteristic features of metastatic Pml and Pten double-null CaP. Furthermore, targeting SREBP in vivo by fatostatin blocked both tumor growth and distant metastasis. Importantly, a high-fat diet (HFD) induced lipid accumulation in prostate tumors and was sufficient to drive metastasis in a nonmetastatic Pten-null mouse model of CaP, and an SREBP signature was highly enriched in metastatic human CaP. Thus, our findings uncover a prometastatic lipogenic program and lend direct genetic and experimental support to the notion that a Western HFD can promote metastasis.
Collapse
Affiliation(s)
- Ming Chen
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jiangwen Zhang
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Katia Sampieri
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,GSK Vaccines, Antigen Identification and Molecular Biology, Siena, Italy
| | - John G Clohessy
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.,Preclinical Murine Pharmacogenetics Facility and Mouse Hospital, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Lourdes Mendez
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Enrique Gonzalez-Billalabeitia
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Xue-Song Liu
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Yu-Ru Lee
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jacqueline Fung
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Jesse M Katon
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Archita Venugopal Menon
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Kaitlyn A Webster
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Christopher Ng
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Maria Dilia Palumbieri
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Moussa S Diolombi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Susanne B Breitkopf
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Julie Teruya-Feldstein
- Department of Pathology, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sabina Signoretti
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Roderick T Bronson
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Mireia Castillo-Martin
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Pathology, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Carlos Cordon-Cardo
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Pier Paolo Pandolfi
- Cancer Research Institute, Beth Israel Deaconess Cancer Center, Department of Medicine and Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
27
|
Kimmel AR, Sztalryd C. The Perilipins: Major Cytosolic Lipid Droplet-Associated Proteins and Their Roles in Cellular Lipid Storage, Mobilization, and Systemic Homeostasis. Annu Rev Nutr 2017; 36:471-509. [PMID: 27431369 DOI: 10.1146/annurev-nutr-071813-105410] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery by Dr. Constantine Londos of perilipin 1, the major scaffold protein at the surface of cytosolic lipid droplets in adipocytes, marked a fundamental conceptual change in the understanding of lipolytic regulation. Focus then shifted from the enzymatic activation of lipases to substrate accessibility, mediated by perilipin-dependent protein sequestration and recruitment. Consequently, the lipid droplet became recognized as a unique, metabolically active cellular organelle and its surface as the active site for novel protein-protein interactions. A new area of investigation emerged, centered on lipid droplets' biology and their role in energy homeostasis. The perilipin family is of ancient origin and has expanded to include five mammalian genes and a growing list of evolutionarily conserved members. Universally, the perilipins modulate cellular lipid storage. This review provides a summary that connects the perilipins to both cellular and whole-body homeostasis.
Collapse
Affiliation(s)
- Alan R Kimmel
- Laboratory of Cellular and Developmental Biology, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, Maryland 20892;
| | - Carole Sztalryd
- The Geriatric Research Education and Clinical Center, Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201.,Division of Endocrinology, Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland 21201;
| |
Collapse
|
28
|
Itabe H, Yamaguchi T, Nimura S, Sasabe N. Perilipins: a diversity of intracellular lipid droplet proteins. Lipids Health Dis 2017; 16:83. [PMID: 28454542 PMCID: PMC5410086 DOI: 10.1186/s12944-017-0473-y] [Citation(s) in RCA: 204] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/22/2017] [Indexed: 01/04/2023] Open
Abstract
Intracellular lipid droplets (LDs) are found in a wide variety of cell types and have been recognized as organelles with unique spherical structures. Although LDs are not stable lipid-depots, they are active sites of neutral lipid metabolism, and comprise neutral lipid or cholesterol cores surrounded by phospholipid monolayers containing specialized proteins. However, sizes and protein compositions vary between cell and tissue types. Proteins of the perilipin family have been associated with surfaces of LDs and all carry a conserved 11-mer repeat motif. Accumulating evidence indicates that all perilipins are involved in LD formation and that all play roles in LD function under differing conditions. In this brief review, we summarize current knowledge of the roles of perilipins and lipid metabolizing enzymes in a variety of mammalian cell types.
Collapse
Affiliation(s)
- Hiroyuki Itabe
- Division of Biological Chemistry, Department of Molecular Biology, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan.
| | - Tomohiro Yamaguchi
- Division of Biological Chemistry, Department of Molecular Biology, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan.,Present address: College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyaka-ku, Nagoya, 463-8521, Japan
| | - Satomi Nimura
- Division of Biological Chemistry, Department of Molecular Biology, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan.,Department of Hospital Pharmaceutics, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan
| | - Naoko Sasabe
- Division of Biological Chemistry, Department of Molecular Biology, Showa University School of Pharmacy, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan
| |
Collapse
|
29
|
Mohktar RAM, Montgomery MK, Murphy RM, Watt MJ. Perilipin 5 is dispensable for normal substrate metabolism and in the adaptation of skeletal muscle to exercise training. Am J Physiol Endocrinol Metab 2016; 311:E128-37. [PMID: 27189934 DOI: 10.1152/ajpendo.00084.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/09/2016] [Indexed: 11/22/2022]
Abstract
Cytoplasmic lipid droplets provide a reservoir for triglyceride storage and are a central hub for fatty acid trafficking in cells. The protein perilipin 5 (PLIN5) is highly expressed in oxidative tissues such as skeletal muscle and regulates lipid metabolism by coordinating the trafficking and the reversible interactions of effector proteins at the lipid droplet. PLIN5 may also regulate mitochondrial function, although this remains unsubstantiated. Hence, the aims of this study were to examine the role of PLIN5 in the regulation of skeletal muscle substrate metabolism during acute exercise and to determine whether PLIN5 is required for the metabolic adaptations and enhancement in exercise tolerance following endurance exercise training. Using muscle-specific Plin5 knockout mice (Plin5(MKO)), we show that PLIN5 is dispensable for normal substrate metabolism during exercise, as reflected by levels of blood metabolites and rates of glycogen and triglyceride depletion that were indistinguishable from control (lox/lox) mice. Plin5(MKO) mice exhibited a functional impairment in their response to endurance exercise training, as reflected by reduced maximal running capacity (20%) and reduced time to fatigue during prolonged submaximal exercise (15%). The reduction in exercise performance was not accompanied by alterations in carbohydrate and fatty acid metabolism during submaximal exercise. Similarly, mitochondrial capacity (mtDNA, respiratory complex proteins, citrate synthase activity) and mitochondrial function (oxygen consumption rate in muscle fiber bundles) were not different between lox/lox and Plin5(MKO) mice. Thus, PLIN5 is dispensable for normal substrate metabolism during exercise and is not required to promote mitochondrial biogenesis or enhance the cellular adaptations to endurance exercise training.
Collapse
Affiliation(s)
- Ruzaidi A M Mohktar
- Monash Biomedicine Discovery Institute, Metabolic Disease and Obesity Program, and Department of Physiology, Monash University, Clayton, Victoria, Australia; Biotechnology Research Institute, Universiti Malaysia Sabah, Jalan UMS, Sabah, Malaysia; and
| | - Magda K Montgomery
- Monash Biomedicine Discovery Institute, Metabolic Disease and Obesity Program, and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Matthew J Watt
- Monash Biomedicine Discovery Institute, Metabolic Disease and Obesity Program, and Department of Physiology, Monash University, Clayton, Victoria, Australia;
| |
Collapse
|
30
|
Ghaste M, Mistrik R, Shulaev V. Applications of Fourier Transform Ion Cyclotron Resonance (FT-ICR) and Orbitrap Based High Resolution Mass Spectrometry in Metabolomics and Lipidomics. Int J Mol Sci 2016; 17:ijms17060816. [PMID: 27231903 PMCID: PMC4926350 DOI: 10.3390/ijms17060816] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/14/2016] [Accepted: 05/17/2016] [Indexed: 02/02/2023] Open
Abstract
Metabolomics, along with other "omics" approaches, is rapidly becoming one of the major approaches aimed at understanding the organization and dynamics of metabolic networks. Mass spectrometry is often a technique of choice for metabolomics studies due to its high sensitivity, reproducibility and wide dynamic range. High resolution mass spectrometry (HRMS) is a widely practiced technique in analytical and bioanalytical sciences. It offers exceptionally high resolution and the highest degree of structural confirmation. Many metabolomics studies have been conducted using HRMS over the past decade. In this review, we will explore the latest developments in Fourier transform mass spectrometry (FTMS) and Orbitrap based metabolomics technology, its advantages and drawbacks for using in metabolomics and lipidomics studies, and development of novel approaches for processing HRMS data.
Collapse
Affiliation(s)
- Manoj Ghaste
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, Denton, TX 76203, USA.
| | | | - Vladimir Shulaev
- Department of Biological Sciences, College of Arts and Sciences, University of North Texas, Denton, TX 76203, USA.
| |
Collapse
|
31
|
Abstract
Spaceflight affects numerous organ systems in the body, leading to metabolic dysfunction that may have long-term consequences. Microgravity-induced alterations in liver metabolism, particularly with respect to lipids, remain largely unexplored. Here we utilize a novel systems biology approach, combining metabolomics and transcriptomics with advanced Raman microscopy, to investigate altered hepatic lipid metabolism in mice following short duration spaceflight. Mice flown aboard Space Transportation System -135, the last Shuttle mission, lose weight but redistribute lipids, particularly to the liver. Intriguingly, spaceflight mice lose retinol from lipid droplets. Both mRNA and metabolite changes suggest the retinol loss is linked to activation of PPARα-mediated pathways and potentially to hepatic stellate cell activation, both of which may be coincident with increased bile acids and early signs of liver injury. Although the 13-day flight duration is too short for frank fibrosis to develop, the retinol loss plus changes in markers of extracellular matrix remodeling raise the concern that longer duration exposure to the space environment may result in progressive liver damage, increasing the risk for nonalcoholic fatty liver disease.
Collapse
|
32
|
Dai C, Kayton NS, Shostak A, Poffenberger G, Cyphert HA, Aramandla R, Thompson C, Papagiannis IG, Emfinger C, Shiota M, Stafford JM, Greiner DL, Herrera PL, Shultz LD, Stein R, Powers AC. Stress-impaired transcription factor expression and insulin secretion in transplanted human islets. J Clin Invest 2016; 126:1857-70. [PMID: 27064285 DOI: 10.1172/jci83657] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 02/24/2016] [Indexed: 12/11/2022] Open
Abstract
Type 2 diabetes is characterized by insulin resistance, hyperglycemia, and progressive β cell dysfunction. Excess glucose and lipid impair β cell function in islet cell lines, cultured rodent and human islets, and in vivo rodent models. Here, we examined the mechanistic consequences of glucotoxic and lipotoxic conditions on human islets in vivo and developed and/or used 3 complementary models that allowed comparison of the effects of hyperglycemic and/or insulin-resistant metabolic stress conditions on human and mouse islets, which responded quite differently to these challenges. Hyperglycemia and/or insulin resistance impaired insulin secretion only from human islets in vivo. In human grafts, chronic insulin resistance decreased antioxidant enzyme expression and increased superoxide and amyloid formation. In human islet grafts, expression of transcription factors NKX6.1 and MAFB was decreased by chronic insulin resistance, but only MAFB decreased under chronic hyperglycemia. Knockdown of NKX6.1 or MAFB expression in a human β cell line recapitulated the insulin secretion defect seen in vivo. Contrary to rodent islet studies, neither insulin resistance nor hyperglycemia led to human β cell proliferation or apoptosis. These results demonstrate profound differences in how excess glucose or lipid influence mouse and human insulin secretion and β cell activity and show that reduced expression of key islet-enriched transcription factors is an important mediator of glucotoxicity and lipotoxicity.
Collapse
|
33
|
Breitkopf SB, Yuan M, Helenius KP, Lyssiotis CA, Asara JM. Triomics Analysis of Imatinib-Treated Myeloma Cells Connects Kinase Inhibition to RNA Processing and Decreased Lipid Biosynthesis. Anal Chem 2015; 87:10995-1006. [PMID: 26434776 PMCID: PMC5585869 DOI: 10.1021/acs.analchem.5b03040] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The combination of metabolomics, lipidomics, and phosphoproteomics that incorporates triple stable isotope labeling by amino acids in cell culture (SILAC) protein labeling, as well as (13)C in vivo metabolite labeling, was demonstrated on BCR-ABL-positive H929 multiple myeloma cells. From 11 880 phosphorylation sites, we confirm that H929 cells are primarily signaling through the BCR-ABL-ERK pathway, and we show that imatinib treatment not only downregulates phosphosites in this pathway but also upregulates phosphosites on proteins involved in RNA expression. Metabolomics analyses reveal that BCR-ABL-ERK signaling in H929 cells drives the pentose phosphate pathway (PPP) and RNA biosynthesis, where pathway inhibition via imatinib results in marked PPP impairment and an accumulation of RNA nucleotides and negative regulation of mRNA. Lipidomics data also show an overall reduction in lipid biosynthesis and fatty acid incorporation with a significant decrease in lysophospholipids. RNA immunoprecipitation studies confirm that RNA degradation is inhibited with short imatinib treatment and transcription is inhibited upon long imatinib treatment, validating the triomics results. These data show the utility of combining mass spectrometry-based "-omics" technologies and reveals that kinase inhibitors may not only downregulate phosphorylation of their targets but also induce metabolic events via increased phosphorylation of other cellular components.
Collapse
Affiliation(s)
- Susanne B. Breitkopf
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Min Yuan
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, United States
| | - Katja P. Helenius
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Costas A. Lyssiotis
- Department of Molecular and Integrative Physiology and Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - John M. Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, United States
| |
Collapse
|
34
|
Trevino MB, Mazur-Hart D, Machida Y, King T, Nadler J, Galkina EV, Poddar A, Dutta S, Imai Y. Liver Perilipin 5 Expression Worsens Hepatosteatosis But Not Insulin Resistance in High Fat-Fed Mice. Mol Endocrinol 2015; 29:1414-25. [PMID: 26296152 DOI: 10.1210/me.2015-1069] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Perilipin 5 (PLIN5) is a lipid droplet (LD) protein highly expressed in oxidative tissues, including the fasted liver. However, its expression also increases in nonalcoholic fatty liver. To determine whether PLIN5 regulates metabolic phenotypes of hepatosteatosis under nutritional excess, liver targeted overexpression of PLIN5 was achieved using adenoviral vector (Ad-PLIN5) in male C57BL/6J mice fed high-fat diet. Mice treated with adenovirus expressing green fluorescent protein (GFP) (Ad-GFP) served as control. Ad-PLIN5 livers increased LD in the liver section, and liquid chromatography with tandem mass spectrometry revealed increases in lipid classes associated with LD, including triacylglycerol, cholesterol ester, and phospholipid classes, compared with Ad-GFP liver. Lipids commonly associated with hepatic lipotoxicity, diacylglycerol, and ceramides, were also increased in Ad-PLIN5 liver. The expression of genes in lipid metabolism regulated by peroxisome proliferator-activated receptor-α was reduced suggestive of slower mobilization of stored lipids in Ad-PLIN5 mice. However, the increase of hepatosteatosis by PLIN5 overexpression did not worsen glucose homeostasis. Rather, serum insulin levels were decreased, indicating better insulin sensitivity in Ad-PLIN5 mice. Moreover, genes associated with liver injury were unaltered in Ad-PLIN5 steatotic liver compared with Ad-GFP control. Phosphorylation of protein kinase B was increased in Ad-PLIN5-transduced AML12 hepatocyte despite of the promotion of fatty acid incorporation to triacylglycerol as well. Collectively, our data indicates that the increase in liver PLIN5 during hepatosteatosis drives further lipid accumulation but does not adversely affect hepatic health or insulin sensitivity.
Collapse
Affiliation(s)
- Michelle B Trevino
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - David Mazur-Hart
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Yui Machida
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Timothy King
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Joseph Nadler
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Elena V Galkina
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Arjun Poddar
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Sucharita Dutta
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| | - Yumi Imai
- Department of Internal Medicine (M.B.T., D.M.-H., Y.M., T.K., J.N., Y.I.), Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Microbiology and Molecular Cell Biology (E.V.G.), Eastern Virginia Medical School, Norfolk, Virginia 23507; Department of Mathematics and Statistics (A.P.), Old Dominion University, Norfolk, Virginia 23529; and Leroy T. Canoles Cancer Research Center (S.D.), Eastern Virginia Medical School, Norfolk, Virginia 23507
| |
Collapse
|