1
|
Goel K, Chhetri A, Ludhiadch A, Munshi A. Current Update on Categorization of Migraine Subtypes on the Basis of Genetic Variation: a Systematic Review. Mol Neurobiol 2024; 61:4804-4833. [PMID: 38135854 DOI: 10.1007/s12035-023-03837-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023]
Abstract
Migraine is a complex neurovascular disorder that is characterized by severe behavioral, sensory, visual, and/or auditory symptoms. It has been labeled as one of the ten most disabling medical illnesses in the world by the World Health Organization (Aagaard et al Sci Transl Med 6(237):237ra65, 2014). According to a recent report by the American Migraine Foundation (Shoulson et al Ann Neurol 25(3):252-9, 1989), around 148 million people in the world currently suffer from migraine. On the basis of presence of aura, migraine is classified into two major subtypes: migraine with aura (Aagaard et al Sci Transl Med 6(237):237ra65, 2014) and migraine without aura. (Aagaard K et al Sci Transl Med 6(237):237ra65, 2014) Many complex genetic mechanisms have been proposed in the pathophysiology of migraine but specific pathways associated with the different subtypes of migraine have not yet been explored. Various approaches including candidate gene association studies (CGAS) and genome-wide association studies (Fan et al Headache: J Head Face Pain 54(4):709-715, 2014). have identified the genetic markers associated with migraine and its subtypes. Several single nucleotide polymorphisms (Kaur et al Egyp J Neurol, Psychiatry Neurosurg 55(1):1-7, 2019) within genes involved in ion homeostasis, solute transport, synaptic transmission, cortical excitability, and vascular function have been associated with the disorder. Currently, the diagnosis of migraine is majorly behavioral with no focus on the genetic markers and thereby the therapeutic intervention specific to subtypes. Therefore, there is a need to explore genetic variants significantly associated with MA and MO as susceptibility markers in the diagnosis and targets for therapeutic interventions in the specific subtypes of migraine. Although the proper characterization of pathways based on different subtypes is yet to be studied, this review aims to make a first attempt to compile the information available on various genetic variants and the molecular mechanisms involved with the development of MA and MO. An attempt has also been made to suggest novel candidate genes based on their function to be explored by future research.
Collapse
Affiliation(s)
- Kashish Goel
- Complex Disease Genomics and Precision Medicine Laboratory, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India, 151401
| | - Aakash Chhetri
- Complex Disease Genomics and Precision Medicine Laboratory, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India, 151401
| | - Abhilash Ludhiadch
- Complex Disease Genomics and Precision Medicine Laboratory, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India, 151401
| | - Anjana Munshi
- Complex Disease Genomics and Precision Medicine Laboratory, Department of Human Genetics and Molecular Medicine, Central University of Punjab, Bathinda, Punjab, India, 151401.
| |
Collapse
|
2
|
Bays HE. Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024. OBESITY PILLARS 2024; 10:100108. [PMID: 38706496 PMCID: PMC11066689 DOI: 10.1016/j.obpill.2024.100108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 05/07/2024]
Abstract
Background This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk. Methods This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership. Results Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles. Conclusions Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.
Collapse
Affiliation(s)
- Harold Edward Bays
- Corresponding author. Louisville Metabolic and Atherosclerosis Research Center, Louisville, KY, 40213, USA.
| |
Collapse
|
3
|
Bays HE, Kirkpatrick CF, Maki KC, Toth PP, Morgan RT, Tondt J, Christensen SM, Dixon DL, Jacobson TA. Obesity, dyslipidemia, and cardiovascular disease: A joint expert review from the Obesity Medicine Association and the National Lipid Association 2024. J Clin Lipidol 2024; 18:e320-e350. [PMID: 38664184 DOI: 10.1016/j.jacl.2024.04.001] [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] [Indexed: 06/28/2024]
Abstract
BACKGROUND This joint expert review by the Obesity Medicine Association (OMA) and National Lipid Association (NLA) provides clinicians an overview of the pathophysiologic and clinical considerations regarding obesity, dyslipidemia, and cardiovascular disease (CVD) risk. METHODS This joint expert review is based upon scientific evidence, clinical perspectives of the authors, and peer review by the OMA and NLA leadership. RESULTS Among individuals with obesity, adipose tissue may store over 50% of the total body free cholesterol. Triglycerides may represent up to 99% of lipid species in adipose tissue. The potential for adipose tissue expansion accounts for the greatest weight variance among most individuals, with percent body fat ranging from less than 5% to over 60%. While population studies suggest a modest increase in blood low-density lipoprotein cholesterol (LDL-C) levels with excess adiposity, the adiposopathic dyslipidemia pattern most often described with an increase in adiposity includes elevated triglycerides, reduced high-density lipoprotein cholesterol (HDL-C), increased non-HDL-C, elevated apolipoprotein B, increased LDL particle concentration, and increased small, dense LDL particles. CONCLUSIONS Obesity increases CVD risk, at least partially due to promotion of an adiposopathic, atherogenic lipid profile. Obesity also worsens other cardiometabolic risk factors. Among patients with obesity, interventions that reduce body weight and improve CVD outcomes are generally associated with improved lipid levels. Given the modest improvement in blood LDL-C with weight reduction in patients with overweight or obesity, early interventions to treat both excess adiposity and elevated atherogenic cholesterol (LDL-C and/or non-HDL-C) levels represent priorities in reducing the risk of CVD.
Collapse
Affiliation(s)
- Harold Edward Bays
- Louisville Metabolic and Atherosclerosis Research Center, Clinical Associate Professor, University of Louisville School of Medicine, 3288 Illinois Avenue, Louisville KY 40213 (Dr Bays).
| | - Carol F Kirkpatrick
- Kasiska Division of Health Sciences, Idaho State University, Pocatello, ID (Dr Kirkpatrick).
| | - Kevin C Maki
- Indiana University School of Public Health, Bloomington, IN (Dr Maki).
| | - Peter P Toth
- CGH Medical Center, Department of Clinical Family and Community Medicine, University of Illinois School of Medicine, Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine (Dr Toth).
| | - Ryan T Morgan
- Oklahoma State University Center for Health Sciences, Principal Investigator at Lynn Health Science Institute, 3555 NW 58th St., STE 910-W, Oklahoma City, OK 73112 (Dr Morgan).
| | - Justin Tondt
- Department of Family and Community Medicine, Penn State College of Medicine, Penn State Milton S. Hershey Medical Center (Dr Tondt)
| | | | - Dave L Dixon
- Deptartment of Pharmacotherapy & Outcomes Science, Virginia Commonwealth University School of Pharmacy 410 N 12th Street, Box 980533, Richmond, VA 23298-0533 (Dr Dixon).
| | - Terry A Jacobson
- Lipid Clinic and Cardiovascular Risk Reduction Program, Emory University Department of Medicine, Atlanta, GA (Dr Jacobson).
| |
Collapse
|
4
|
Li RX, Chen LY, Limbu SM, Yao B, Qian YF, Zhou WH, Chen LQ, Qiao F, Zhang ML, Du ZY, Luo Y. Atorvastatin remodels lipid distribution between liver and adipose tissues through blocking lipoprotein efflux in fish. Am J Physiol Regul Integr Comp Physiol 2023; 324:R281-R292. [PMID: 36572553 DOI: 10.1152/ajpregu.00222.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The regulation of cholesterol metabolism in fish is still unclear. Statins play important roles in promoting cholesterol metabolism development in mammals. However, studies on the role of statins in cholesterol metabolism in fish are currently limited. The present study evaluated the effects of statins on cholesterol metabolism in fish. Nile tilapia (Oreochromis niloticus) were fed on control diets supplemented with three atorvastatin levels (0, 12, and 24 mg/kg diet, ATV0, ATV12, and ATV24, respectively) for 4 wk. Intriguingly, the results showed that both atorvastatin treatments increased hepatic cholesterol and triglyceride contents mainly through inhibiting bile acid synthesis and efflux, and compensatorily enhancing cholesterol synthesis in fish liver (P < 0.05). Moreover, atorvastatin treatment significantly inhibited hepatic very-low-density lipoprotein (VLDL) assembly and thus decreased serum VLDL content (P < 0.05). However, fish treated with atorvastatin significantly reduced cholesterol and triglycerides contents in adipose tissue (P < 0.05). Further molecular analysis showed that atorvastatin treatment promoted cholesterol synthesis and lipogenesis pathways, but inhibited lipid catabolism and low-density lipoprotein (LDL) uptake in the adipose tissue of fish (P < 0.05). In general, atorvastatin induced the remodeling of lipid distribution between liver and adipose tissues through blocking VLDL efflux from the liver to adipose tissue of fish. Our results provide a novel regulatory pattern of cholesterol metabolism response caused by atorvastatin in fish, which is distinct from mammals: cholesterol inhibition by atorvastatin activates hepatic cholesterol synthesis and inhibits its efflux to maintain cholesterol homeostasis, consequently reduces cholesterol storage in fish adipose tissue.
Collapse
Affiliation(s)
- Rui-Xin Li
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Ling-Yun Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Samwel M Limbu
- Department of Aquaculture Technology, School of Aquatic Sciences and Fisheries Technology, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Bing Yao
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Yi-Fan Qian
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Wen-Hao Zhou
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Li-Qiao Chen
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Fang Qiao
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Mei-Ling Zhang
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Zhen-Yu Du
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Yuan Luo
- LANEH, School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| |
Collapse
|
5
|
Deletion of LDLRAP1 Induces Atherosclerotic Plaque Formation, Insulin Resistance, and Dysregulated Insulin Response in Adipose Tissue. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:1092-1108. [PMID: 35460615 PMCID: PMC9253916 DOI: 10.1016/j.ajpath.2022.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/18/2022] [Accepted: 03/28/2022] [Indexed: 12/25/2022]
Abstract
Dyslipidemia, vascular inflammation, obesity, and insulin resistance often overlap and exacerbate each other. Mutations in low density lipoprotein receptor adaptor protein-1 (LDLRAP1) lead to LDLR malfunction and are associated with the autosomal recessive hypercholesterolemia disorder in humans. However, direct causality on atherogenesis in a defined preclinical model has not been reported. The objective of this study was to test the hypothesis that deletion of LDLRAP1 will lead to hypercholesteremia and atherosclerosis. LDLRAP1-/- mice fed a high-fat Western diet had significantly increased plasma cholesterol and triglyceride concentrations accompanied with significantly increased plaque burden compared with wild-type controls. Unexpectedly, LDLRAP1-/- mice gained significantly more weight compared with controls. Even on a chow diet, LDLRAP1-/- mice were insulin-resistant, and calorimetric studies suggested an altered metabolic profile. The study showed that LDLRAP1 is highly expressed in visceral adipose tissue, and LDLRAP1-/- adipocytes are significantly larger, have reduced glucose uptake and AKT phosphorylation, but have increased CD36 expression. Visceral adipose tissue from LDLRAP1-/- mice was hypoxic and had gene expression signatures of dysregulated lipid storage and energy homeostasis. These data are the first to indicate that lack of LDLRAP1 directly leads to atherosclerosis in mice and also plays an unanticipated metabolic regulatory role in adipose tissue. LDLRAP1 may link atherosclerosis and hypercholesterolemia with common comorbidities of obesity and insulin resistance.
Collapse
|
6
|
Batu Oto B, Aykut V, Güneş M, Korkmaz R, İsman FK, Agirbasli M. Low levels of soluble low-density lipoprotein receptor-related protein 1 in patients with type 2 diabetes mellitus and diabetic retinopathy. Exp Eye Res 2022; 215:108921. [PMID: 34999080 DOI: 10.1016/j.exer.2022.108921] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/15/2021] [Accepted: 01/02/2022] [Indexed: 11/30/2022]
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP-1) is a large transmembrane receptor. LRP-1 plays a role in diverse cellular processes, including lipid metabolism, cell growth, migration, and regeneration. Soluble form of LRP-1 (sLRP-1) can be detected in serum. sLRP-1 can serve as a biomarker of atherosclerosis and cardiometabolic diseases. This study investigated the concentrations of the circulating serum sLRP-1 in patients with retinopathy and type 2 diabetes mellitus. Fifty-two patients with diabetic retinopathy and 71 controls were enrolled based on well-defined eligibility criteria. Venous blood samples were collected after 12 h of fasting. sLRP-1 concentrations were measured using the commercially available ELISA in an accredited laboratory. The mean age of patients and control groups were 63.6 and 48.5 years, respectively. The median disease duration was 8.1 years. The median serum sLRP-1 levels were lower in patients with diabetic retinopathy compared to the controls (2.11 μg/mL versus 2.44 μg/mL, p = 0.034). No significant correlation was observed between the sLRP-1 and serum lipid levels. The sLRP-1 levels are low in patients with diabetic retinopathy compared to healthy controls, and future studies are needed to assess sLRP-1 as a potential biomarker in diabetic retinopathy.
Collapse
Affiliation(s)
- Bilge Batu Oto
- Department of Ophthalmology, Istanbul University-Cerrahpaşa, Cerrahpaşa Medical Faculty, Turkey
| | - Veysel Aykut
- Department of Ophthalmology, Istanbul Medeniyet University Faculty of Medicine, Istanbul, Turkey
| | - Medine Güneş
- Department of Ophthalmology, Istanbul Medeniyet University Faculty of Medicine, Istanbul, Turkey
| | - Rabia Korkmaz
- Department of Clinical Chemistry, Göztepe Prof Dr Süleyman Yalçın Şehir Hastanesi, Istanbul, Turkey; Department of Clinical Chemistry, Istanbul Medeniyet University Faculty of Medicine, Istanbul, Turkey
| | - Ferruh K İsman
- Department of Clinical Chemistry, Göztepe Prof Dr Süleyman Yalçın Şehir Hastanesi, Istanbul, Turkey; Department of Clinical Chemistry, Istanbul Medeniyet University Faculty of Medicine, Istanbul, Turkey
| | - Mehmet Agirbasli
- Department of Cardiology, Istanbul Medeniyet University Faculty of Medicine, Istanbul, Turkey; Department of Cardiology, Göztepe Prof Dr Süleyman Yalçın Şehir Hastanesi, Istanbul, Turkey.
| |
Collapse
|
7
|
Moin ASM, Al-Qaissi A, Sathyapalan T, Atkin SL, Butler AE. Hypoglycaemia in type 2 diabetes exacerbates amyloid-related proteins associated with dementia. Diabetes Obes Metab 2021; 23:338-349. [PMID: 33026133 DOI: 10.1111/dom.14220] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/17/2020] [Accepted: 10/04/2020] [Indexed: 12/12/2022]
Abstract
AIMS Hypoglycaemia in diabetes (T2D) may increase the risk of Alzheimer's disease (AD). We hypothesized that hypoglycaemia-induced amyloid-related protein changes would be exacerbated in T2D. MATERIALS AND METHODS A prospective, parallel study in T2D (n = 23) and controls (n = 23). Subjects underwent insulin-induced hypoglycaemia with blood sampling at baseline, hypoglycaemia and post-hypoglycaemia; proteomic analysis of amyloid-related proteins was undertaken. RESULTS At baseline, amyloid-precursor protein (APP) (P < .01) was elevated and alpha-synuclein (SNCA) (P < .01) reduced in T2D. At hypoglycaemia, amyloid P-component (P < .01) was elevated and SNCA (P < .05) reduced in T2D; APP (P < .01) and noggin (P < .05) were elevated and SNCA (P < .01) reduced in controls. In the post-hypoglycaemia follow-up period, APP and microtubule-associated protein tau normalized in controls but showed a below-baseline decrease in T2D; noggin normalized in both; SNCA normalized in T2D, with a below-baseline decrease in controls. CONCLUSION The AD-associated protein pattern found in T2D, with basal elevated APP and reduced SNCA, was exaggerated by hypoglycaemia with increased APP and decreased SNCA. Additional AD-associated protein levels that changed in response to hypoglycaemia, particularly in T2D, included amyloid P-component, microtubule-associated protein tau, apolipoproteins A1 and E3, pappalysin and noggin. These results are in accordance with the reported detrimental effects of hypoglycaemia.
Collapse
Affiliation(s)
- Abu Saleh Md Moin
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
| | - Ahmed Al-Qaissi
- Academic Endocrinology, Diabetes and Metabolism, Hull York Medical School, Hull, UK
- Leeds Medical School, Leeds, UK
| | | | | | - Alexandra E Butler
- Diabetes Research Center (DRC), Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation (QF), Doha, Qatar
| |
Collapse
|
8
|
Metabolic Health in Obese Subjects-Is There a Link to Lactoferrin and Lactoferrin Receptor-Related Gene Polymorphisms? Nutrients 2020; 12:nu12092843. [PMID: 32957486 PMCID: PMC7551427 DOI: 10.3390/nu12092843] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 08/25/2020] [Accepted: 09/15/2020] [Indexed: 12/21/2022] Open
Abstract
This study aimed to evaluate the association of genetic variants in lactoferrin (LTF) metabolism-related genes with the prevalence of metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUHO). In total, 161 MHO and 291 MUHO subjects were recruited to the study. The following polymorphisms were genotyped: low-density lipoprotein receptor-related protein (LRP) 2 rs2544390, LRP1 rs4759277, LRP1 rs1799986, LTF rs1126477, LTF rs2239692 and LTF rs1126478. We found significant differences in the genotype frequencies of LTF rs2239692 between MHO and MUHO subjects, with the CT variant associated with lower odds of developing metabolic syndrome than the TT variant. In the total population, significant differences in body weight and waist circumference (WC) were identified between LTF rs1126477 gene variants. A similar association with WC was observed in MUHO subjects, while significant differences in body mass index and low-density lipoprotein cholesterol levels were discovered between LTF rs1126477 gene variants in MHO subjects. Besides, there were significant differences in diastolic blood pressure between LRP1 rs1799986 gene variants in MUHO subjects, as well as in WC and high-density lipoprotein cholesterol levels between LRP1 rs4759277 gene variants in MHO subjects. In conclusion, selected lactoferrin and lactoferrin receptor-related gene variants may be associated with the prevalence of metabolically healthy or metabolically unhealthy obesity.
Collapse
|
9
|
Fischer AW, Albers K, Schlein C, Sass F, Krott LM, Schmale H, Gordts PLSM, Scheja L, Heeren J. PID1 regulates insulin-dependent glucose uptake by controlling intracellular sorting of GLUT4-storage vesicles. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1592-1603. [PMID: 30904610 PMCID: PMC6624118 DOI: 10.1016/j.bbadis.2019.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 12/26/2022]
Abstract
The phosphotyrosine interacting domain-containing protein 1 (PID1) serves as a cytosolic adaptor protein of the LDL receptor-related protein 1 (LRP1). By regulating its intracellular trafficking, PID1 controls the hepatic, LRP1-dependent clearance of pro-atherogenic lipoproteins. In adipose and muscle tissues, LRP1 is present in endosomal storage vesicles containing the insulin-responsive glucose transporter 4 (GLUT4). This prompted us to investigate whether PID1 modulates GLUT4 translocation and function via its interaction with the LRP1 cytosolic domain. We initially evaluated this in primary brown adipocytes as we observed an inverse correlation between brown adipose tissue glucose uptake and expression of LRP1 and PID1. Insulin stimulation in wild type brown adipocytes induced LRP1 and GLUT4 translocation from endosomal storage vesicles to the cell surface. Loss of PID1 expression in brown adipocytes prompted LRP1 and GLUT4 sorting to the plasma membrane independent of insulin signaling. When placed on a diabetogenic high fat diet, systemic and adipocyte-specific PID1-deficient mice presented with improved hyperglycemia and glucose tolerance as well as reduced basal plasma insulin levels compared to wild type control mice. Moreover, the improvements in glucose parameters associated with increased glucose uptake in adipose and muscle tissues from PID1-deficient mice. The data provide evidence that PID1 serves as an insulin-regulated retention adaptor protein controlling translocation of LRP1 in conjunction with GLUT4 to the plasma membrane of adipocytes. Notably, loss of PID1 corrects for insulin resistance-associated hyperglycemia emphasizing its pivotal role and therapeutic potential in the regulation of glucose homeostasis.
Collapse
Affiliation(s)
- Alexander W Fischer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Kirstin Albers
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Frederike Sass
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Lucia M Krott
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Hartwig Schmale
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Philip L S M Gordts
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg Eppendorf, 20246 Hamburg, Germany.
| |
Collapse
|
10
|
Nakajima K, Tokita Y, Tanaka A, Takahashi S. The VLDL receptor plays a key role in the metabolism of postprandial remnant lipoproteins. Clin Chim Acta 2019; 495:382-393. [PMID: 31078566 DOI: 10.1016/j.cca.2019.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 12/21/2022]
Abstract
A new concept to account for the process of postprandial remnant lipoprotein metabolism is proposed based on the characteristics of lipoprotein particles and their receptors. The characteristics of remnant lipoprotein (RLP) were investigated using an immuno-separation method. The majority of the postprandial lipoproteins increased after fat intake was shown to be VLDL remnants, not chylomicron (CM) remnants, based on the significantly high ratio of apoB100/apoB48 in the RLP and the high degree of similarity in the particle size of the apoB48 and apoB100 carrying lipoproteins, which fluctuate in parallel during a 6 h period after fat intake. The VLDL receptor was discovered as a receptor for TG-rich lipoprotein metabolism and is located in peripheral tissues such as skeletal muscle, adipose tissue, etc., but not in the liver. Postprandial VLDL particles are strongly bound and internalized into cells expressing the VLDL receptor. Ligands that bind to VLDL receptor, such as LPL and Lp(a), present in RLP. The presence of various specific ligands in VLDL remnants may enhance the capacity for binding to the VLDL receptor, which play the role primarily for energy delivery to the peripheral tissues, but is also a causal factor in atherogenic diseases when excessively and/or continuously remained in plasma.
Collapse
Affiliation(s)
- Katsuyuki Nakajima
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan; Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan.
| | - Yoshiharu Tokita
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan; Graduate School of Health Sciences, Gunma University, Maebashi, Gunma, Japan
| | - Akira Tanaka
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan
| | - Sadao Takahashi
- Laboratory of Clinical Nutrition and Medicine, Kagawa Nutrition University, Tokyo, Japan; Division of Diabetes, Ageo Central General Hospital, Saitama, Japan
| |
Collapse
|
11
|
Fischer AW, Albers K, Krott LM, Hoffzimmer B, Heine M, Schmale H, Scheja L, Gordts PLSM, Heeren J. The adaptor protein PID1 regulates receptor-dependent endocytosis of postprandial triglyceride-rich lipoproteins. Mol Metab 2018; 16:88-99. [PMID: 30100244 PMCID: PMC6158030 DOI: 10.1016/j.molmet.2018.07.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/20/2018] [Accepted: 07/25/2018] [Indexed: 01/19/2023] Open
Abstract
Objective Insulin resistance is associated with impaired receptor dependent hepatic uptake of triglyceride-rich lipoproteins (TRL), promoting hypertriglyceridemia and atherosclerosis. Next to low-density lipoprotein (LDL) receptor (LDLR) and syndecan-1, the LDLR-related protein 1 (LRP1) stimulated by insulin action contributes to the rapid clearance of TRL in the postprandial state. Here, we investigated the hypothesis that the adaptor protein phosphotyrosine interacting domain-containing protein 1 (PID1) regulates LRP1 function, thereby controlling hepatic endocytosis of postprandial lipoproteins. Methods Localization and interaction of PID1 and LRP1 in cultured hepatocytes was studied by confocal microscopy of fluorescent tagged proteins, by indirect immunohistochemistry of endogenous proteins, by GST-based pull down and by immunoprecipitation experiments. The in vivo relevance of PID1 was assessed using whole body as well as liver-specific Pid1-deficient mice on a wild type or Ldlr-deficient (Ldlr−/−) background. Intravital microscopy was used to study LRP1 translocation in the liver. Lipoprotein metabolism was investigated by lipoprotein profiling, gene and protein expression as well as organ-specific uptake of radiolabelled TRL. Results PID1 co-localized in perinuclear endosomes and was found associated with LRP1 under fasting conditions. We identified the distal NPxY motif of the intracellular C-terminal domain (ICD) of LRP1 as the site critical for the interaction with PID1. Insulin-mediated NPxY-phosphorylation caused the dissociation of PID1 from the ICD, causing LRP1 translocation to the plasma membrane. PID1 deletion resulted in higher LRP1 abundance at the cell surface, higher LDLR protein levels and, paradoxically, reduced total LRP1. The latter can be explained by higher receptor shedding, which we observed in cultured Pid1-deficient hepatocytes. Consistently, PID1 deficiency alone led to increased LDLR-dependent endocytosis of postprandial lipoproteins and lower plasma triglycerides. In contrast, hepatic PID1 deletion on an Ldlr−/− background reduced lipoprotein uptake into liver and caused plasma TRL accumulation. Conclusions By acting as an insulin-dependent retention adaptor, PID1 serves as a regulator of LRP1 function controlling the disposal of postprandial lipoproteins. PID1 inhibition provides a novel approach to lower plasma levels of pro-atherogenic TRL remnants by stimulating endocytic function of both LRP1 and LDLR in the liver. PID1 is a retention adaptor protein that regulates activity of the endocytic receptor LDL receptor-related protein 1 (LRP1). PID1 regulates the insulin-dependent LRP1-mediated endocytosis of lipoproteins in vivo. PID1 deficiency in liver reduces LRP1 levels via cell surface shedding, and paradoxically increases LDL receptor activity. PID1 antagonism has therapeutic potential to reduce pro-atherogenic lipoproteins in hyperlipidemic and diabetic patients.
Collapse
Affiliation(s)
- Alexander W Fischer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Kirstin Albers
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Lucia M Krott
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Britta Hoffzimmer
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Markus Heine
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Hartwig Schmale
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Ludger Scheja
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Philip L S M Gordts
- Department of Medicine, University of California, La Jolla, San Diego, CA, 92093, USA
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany.
| |
Collapse
|
12
|
van de Sluis B, Wijers M, Herz J. News on the molecular regulation and function of hepatic low-density lipoprotein receptor and LDLR-related protein 1. Curr Opin Lipidol 2017; 28:241-247. [PMID: 28301372 PMCID: PMC5482905 DOI: 10.1097/mol.0000000000000411] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW Clearing of atherogenic lipoprotein particles by the liver requires hepatic low-density lipoprotein receptor (LDLR) and LDLR-related protein 1 (LRP1). This review highlights recent studies that have expanded our understanding of the molecular regulation and metabolic functions of LDLR and LRP1 in the liver. RECENT FINDINGS Various proteins orchestrate the intracellular trafficking of LDLR and LRP1. After internalization, the receptors are redirected via recycling endosomes to the cell surface. Several new endocytic proteins that facilitate the endosomal trafficking of LDLR and consequently the clearance of circulating LDL cholesterol have recently been reported. Mutations in some of these proteins cause hypercholesterolemia in human. In addition, LRP1 controls cellular cholesterol efflux by modulating the expression of ABCA1 and ABCG1, and hepatic LRP1 protects against diet-induced hepatic insulin resistance and steatosis through the regulation of insulin receptor trafficking. SUMMARY LDLR and LRP1 have prominent roles in cellular and organismal cholesterol homeostasis. Their functioning, including their trafficking in the cell, is controlled by numerous proteins. Comprehensive studies into the molecular regulation of LDLR and LRP1 trafficking have advanced our fundamental understanding of cholesterol homeostasis, and these insights may lead to novel therapeutic strategies for atherosclerosis, hyperlipidemia and insulin resistance in the future.
Collapse
Affiliation(s)
- Bart van de Sluis
- Section of Molecular Genetics, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen
| | - Melinde Wijers
- Section of Molecular Genetics, Department of Pediatrics, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, 9713 AV, Groningen
| | - Joachim Herz
- Departments of Molecular Genetics, Neuroscience, Neurology and Neurotherapeutics, Center for Translational Neurodegeneration Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| |
Collapse
|
13
|
Au DT, Strickland DK, Muratoglu SC. The LDL Receptor-Related Protein 1: At the Crossroads of Lipoprotein Metabolism and Insulin Signaling. J Diabetes Res 2017; 2017:8356537. [PMID: 28584820 PMCID: PMC5444004 DOI: 10.1155/2017/8356537] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/11/2017] [Indexed: 12/30/2022] Open
Abstract
The metabolic syndrome is an escalating worldwide public health concern. Defined by a combination of physiological, metabolic, and biochemical factors, the metabolic syndrome is used as a clinical guideline to identify individuals with a higher risk for type 2 diabetes and cardiovascular disease. Although risk factors for type 2 diabetes and cardiovascular disease have been known for decades, the molecular mechanisms involved in the pathophysiology of these diseases and their interrelationship remain unclear. The LDL receptor-related protein 1 (LRP1) is a large endocytic and signaling receptor that is widely expressed in several tissues. As a member of the LDL receptor family, LRP1 is involved in the clearance of chylomicron remnants from the circulation and has been demonstrated to be atheroprotective. Recently, studies have shown that LRP1 is involved in insulin receptor trafficking and regulation and glucose metabolism. This review summarizes the role of tissue-specific LRP1 in insulin signaling and its potential role as a link between lipoprotein and glucose metabolism in diabetes.
Collapse
Affiliation(s)
- Dianaly T. Au
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dudley K. Strickland
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Selen C. Muratoglu
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- *Selen C. Muratoglu:
| |
Collapse
|
14
|
Ding Y, Xian X, Holland WL, Tsai S, Herz J. Low-Density Lipoprotein Receptor-Related Protein-1 Protects Against Hepatic Insulin Resistance and Hepatic Steatosis. EBioMedicine 2016; 7:135-45. [PMID: 27322467 PMCID: PMC4913705 DOI: 10.1016/j.ebiom.2016.04.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 11/15/2022] Open
Abstract
Low-density lipoprotein receptor-related protein-1 (LRP1) is a multifunctional uptake receptor for chylomicron remnants in the liver. In vascular smooth muscle cells LRP1 controls reverse cholesterol transport through platelet-derived growth factor receptor β (PDGFR-β) trafficking and tyrosine kinase activity. Here we show that LRP1 regulates hepatic energy homeostasis by integrating insulin signaling with lipid uptake and secretion. Somatic inactivation of LRP1 in the liver (hLRP1KO) predisposes to diet-induced insulin resistance with dyslipidemia and non-alcoholic hepatic steatosis. On a high-fat diet, hLRP1KO mice develop a severe Metabolic Syndrome secondary to hepatic insulin resistance, reduced expression of insulin receptors on the hepatocyte surface and decreased glucose transporter 2 (GLUT2) translocation. While LRP1 is also required for efficient cell surface insulin receptor expression in the absence of exogenous lipids, this latent state of insulin resistance is unmasked by exposure to fatty acids. This further impairs insulin receptor trafficking and results in increased hepatic lipogenesis, impaired fatty acid oxidation and reduced very low density lipoprotein (VLDL) triglyceride secretion. Hepatic LRP1 deficiency in a mouse model (hLRP1KO) predisposes to diet-induced insulin resistance, dyslipidemia, and obesity. Insulin resistance in the hLRP1KO mouse results from reduced cell surface expression of insulin receptor (IR) and impaired translocation of glucose transporter 2 (GLUT2). Excess fatty acids in hLRP1KO mice shift hepatic fatty acid metabolism from an oxidative to a synthetic state, resulting in hepatic steatosis.
LRP1 is a multifunctional transmembrane receptor with essential functions in lipoprotein metabolism and subcellular receptor tyrosine kinase trafficking. A mouse model of hepatic LRP1 deficiency integrates the hallmark findings in Metabolic Syndrome - insulin resistance, dyslipidemia, and hepatic steatosis - with impaired glucose metabolism and altered hepatic fatty acid metabolism as a consequence of reduced insulin receptor trafficking and signaling. These findings underscore the central role of LRP1 in overall energy homeostasis, and specifically liver glucose and fatty acid metabolism.
Collapse
Affiliation(s)
- Yinyuan Ding
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, TX 75390, USA; Key Laboratory of Medical Electrophysiology, Ministry of Education of China, China; Institute of Cardiovascular Research, Sichuan Medical University, Luzhou 646000, China
| | - Xunde Xian
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - William L Holland
- Department of Internal Medicine, Touchstone Diabetes Center, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shirling Tsai
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX 75390, USA; Dallas VA Medical Center, Dallas, TX 75216, USA
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, TX 75390, USA; Center for Translational Neurodegeneration Research, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX 75390, USA; Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
15
|
Abstract
PURPOSE OF REVIEW Adipose tissue is a critical endocrine and immunological organ that regulates systemic energy homeostasis. During the pathogenesis of obesity, adipocyte hypertrophy is accompanied by adipose tissue inflammation, impeding insulin sensitivity and endocrine function of adipose tissue and other tissues. Adipocyte cholesterol accumulates in proportion to triglyceride as adipocytes undergo hypertrophy. Recent studies suggest that dietary cholesterol contributes to increased adipocyte cholesterol. However, how dietary cholesterol accumulates in adipocytes and its metabolic consequences are poorly understood. This review summarizes recent advances in knowledge of adipocyte cholesterol balance and highlights the emerging role of dietary cholesterol in adipose tissue cholesterol balance, inflammation, and systemic energy metabolism. RECENT FINDINGS Perturbation of cholesterol balance in adipocytes alters intracellular cholesterol distribution and modulates adipocyte insulin and proinflammatory signaling. Adipocyte cholesterol levels are maintained by a balance between dietary cholesterol uptake from triglyceride-enriched lipoproteins and cellular cholesterol efflux to HDL. Recent animal studies established a critical role for dietary cholesterol in promoting adipose tissue inflammation, thereby worsening obesity-mediated metabolic complications. SUMMARY Recent studies identified high dietary cholesterol as a potentiator of adipose tissue inflammation and dysfunction. Reducing excessive dietary cholesterol intake is suggested as a simple, but novel, way to attenuate obesity-associated metabolic diseases.
Collapse
Affiliation(s)
- Soonkyu Chung
- Department of Nutrition and Health Sciences, University of Nebraska, Lincoln, NE 68516
| | - John S. Parks
- Department of Internal Medicine/Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157
- Corresponding author: John S. Parks; Department of Internal Medicine/Section on Molecular Medicine, Wake Forest School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157 phone: 336-716-2145 fax: 336-716-6279
| |
Collapse
|
16
|
Dietary Lipid Levels Influence Lipid Deposition in the Liver of Large Yellow Croaker (Larimichthys crocea) by Regulating Lipoprotein Receptors, Fatty Acid Uptake and Triacylglycerol Synthesis and Catabolism at the Transcriptional Level. PLoS One 2015; 10:e0129937. [PMID: 26114429 PMCID: PMC4482732 DOI: 10.1371/journal.pone.0129937] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/14/2015] [Indexed: 01/09/2023] Open
Abstract
Ectopic lipid accumulation has been observed in fish fed a high-lipid diet. However, no information is available on the mechanism by which dietary lipid levels comprehensively regulate lipid transport, uptake, synthesis and catabolism in fish. Therefore, the present study aimed to gain further insight into how dietary lipids affect lipid deposition in the liver of large yellow croaker(Larimichthys crocea). Fish (150.00±4.95 g) were fed a diet with a low (6%), moderate (12%, the control diet) or high (18%) crude lipid content for 10 weeks. Growth performance, plasma biochemical indexes, lipid contents and gene expression related to lipid deposition, including lipoprotein assembly and clearance, fatty acid uptake and triacylglycerol synthesis and catabolism, were assessed. Growth performance was not significantly affected. However, the hepato-somatic and viscera-somatic indexes as well as plasma triacylglycerol, non-esterified fatty acids and LDL-cholesterol levels were significantly increased in fish fed the high-lipid diet. In the livers of fish fed the high-lipid diet, the expression of genes related to lipoprotein clearance (LDLR) and fatty acid uptake (FABP11) was significantly up-regulated, whereas the expression of genes involved in lipoprotein assembly (apoB100), triacylglycerol synthesis and catabolism (DGAT2, CPT I) was significantly down-regulated compared with fish fed the control diet, and hepatic lipid deposition increased. In fish fed the low-lipid diet, the expression of genes associated with lipoprotein assembly and clearance (apoB100, LDLR, LRP-1), fatty acid uptake (CD36, FATP1, FABP3) and triacylglycerol synthesis (FAS) was significantly increased, whereas the expression of triacylglycerol catabolism related genes (ATGL, CPT I) was reduced compared with fish fed the control diet. However, hepatic lipid content in fish fed the low-lipid diet decreased mainly due to low dietary lipid intake. In summary, findings of this study provide molecular insight into the role of lipid deposition in the liver in response to different dietary lipid contents.
Collapse
|
17
|
Covarrubias R, Wilhelm AJ, Major AS. Specific deletion of LDL receptor-related protein on macrophages has skewed in vivo effects on cytokine production by invariant natural killer T cells. PLoS One 2014; 9:e102236. [PMID: 25050824 PMCID: PMC4106787 DOI: 10.1371/journal.pone.0102236] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 06/17/2014] [Indexed: 12/31/2022] Open
Abstract
Expression of molecules involved in lipid homeostasis such as the low density lipoprotein receptor (LDLr) on antigen presenting cells (APCs) has been shown to enhance invariant natural killer T (iNKT) cell function. However, the contribution to iNKT cell activation by other lipoprotein receptors with shared structural and ligand binding properties to the LDLr has not been described. In this study, we investigated whether a structurally related receptor to the LDLr, known as LDL receptor-related protein (LRP), plays a role in iNKT cell activation. We found that, unlike the LDLr which is highly expressed on all immune cells, the LRP was preferentially expressed at high levels on F4/80+ macrophages (MΦ). We also show that CD169+ MΦs, known to present antigen to iNKT cells, exhibited increased expression of LRP compared to CD169- MΦs. To test the contribution of MΦ LRP to iNKT cell activation we used a mouse model of MΦ LRP conditional knockout (LRP-cKO). LRP-cKO MΦs pulsed with glycolipid alpha-galactosylceramide (αGC) elicited normal IL-2 secretion by iNKT hybridoma and in vivo challenge of LRP-cKO mice led to normal IFN-γ, but blunted IL-4 response in both serum and intracellular expression by iNKT cells. Flow cytometric analyses show similar levels of MHC class-I like molecule CD1d on LRP-cKO MΦs and normal glycolipid uptake. Survey of the iNKT cell compartment in LRP-cKO mice revealed intact numbers and percentages and no homeostatic disruption as evidenced by the absence of programmed death-1 and Ly-49 surface receptors. Mixed bone marrow chimeras showed that the inability iNKT cells to make IL-4 is cell extrinsic and can be rescued in the presence of wild type APCs. Collectively, these data demonstrate that, although MΦ LRP may not be necessary for IFN-γ responses, it can contribute to iNKT cell activation by enhancing early IL-4 secretion.
Collapse
Affiliation(s)
- Roman Covarrubias
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Ashley J. Wilhelm
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Amy S. Major
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| |
Collapse
|
18
|
Low molecular weight heparin-induced increase in chylomicron-remnants clearance, is associated with decreased plasma TNF-α level and increased hepatic lipase activity. Thromb Res 2014; 133:688-92. [DOI: 10.1016/j.thromres.2014.01.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/17/2013] [Accepted: 01/15/2014] [Indexed: 11/21/2022]
|
19
|
Nasarre L, Juan-Babot O, Gastelurrutia P, Llucia-Valldeperas A, Badimon L, Bayes-Genis A, Llorente-Cortés V. Low density lipoprotein receptor-related protein 1 is upregulated in epicardial fat from type 2 diabetes mellitus patients and correlates with glucose and triglyceride plasma levels. Acta Diabetol 2014; 51:23-30. [PMID: 23096408 DOI: 10.1007/s00592-012-0436-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 10/08/2012] [Indexed: 11/27/2022]
Abstract
Lipoprotein receptor expression plays a crucial role in the pathophysiology of adipose tissue in in vivo models of diabetes. However, there are no studies in diabetic patients. The aims of this study were to analyze (a) low-density lipoprotein receptor-related protein 1 (LRP1) and very low-density lipoprotein receptor (VLDLR) expression in epicardial and subcutaneous fat from type 2 diabetes mellitus compared with nondiabetic patients and (b) the possible correlation between the expression of these receptors and plasmatic parameters. Adipose tissue biopsy samples were obtained from diabetic (n = 54) and nondiabetic patients (n = 22) undergoing cardiac surgery before the initiation of cardiopulmonary bypass. Adipose LRP1 and VLDLR expression was analyzed at mRNA level by real-time PCR and at protein level by Western blot analysis. Adipose samples were also subjected to lipid extraction, and fat cholesterol ester, triglyceride, and free cholesterol contents were analyzed by thin-layer chromatography. LRP1 expression was higher in epicardial fat from diabetic compared with nondiabetic patients (mRNA 17.63 ± 11.37 versus 7.01 ± 4.86; P = 0.02; protein 11.23 ± 7.23 versus 6.75 ± 5.02, P = 0.04). VLDLR expression was also higher in epicardial fat from diabetic patients but only at mRNA level (231.25 ± 207.57 versus 56.64 ± 45.64, P = 0.02). No differences were found in the expression of LRP1 or VLDLR in the subcutaneous fat from diabetic compared with nondiabetic patients. Epicardial LRP1 and VLDLR mRNA overexpression positively correlated with plasma triglyceride levels (R(2) = 0.50, P = 0.01 and R(2) = 0.44, P = 0.03, respectively) and epicardial LRP1 also correlated with plasma glucose levels (R(2) = 0.33, P = 0.03). These results suggest that epicardial overexpression of certain lipoprotein receptors such as LRP1 and VLDLR expression may play a key role in the alterations of lipid metabolism associated with type 2 diabetes mellitus.
Collapse
Affiliation(s)
- L Nasarre
- Cardiovascular Research Center, CSIC-ICCC, IIB-Sant Pau, Hospital de la Santa Creu i Sant Pau, UAB, Sant Antoni Mª Claret, 167, 08025, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
20
|
Aledo R, Costales P, Ciudad C, Noé V, Llorente-Cortes V, Badimon L. Molecular and functional characterization of LRP1 promoter polymorphism c.1-25 C>G (rs138854007). Atherosclerosis 2014; 233:178-85. [PMID: 24529141 DOI: 10.1016/j.atherosclerosis.2013.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 11/20/2013] [Accepted: 12/05/2013] [Indexed: 10/25/2022]
Abstract
The transcription of the Low-density lipoprotein receptor-related protein (LRP1) is upregulated by aggregated LDL (agLDL) and angiotensin II (AngII) in human vascular smooth muscle cells (hVSMC). The polymorphism c.1-25C>G creates a new GC-box in the LRP1 promoter recognized by Sp1/Sp3 transcription factors. The aims of this study were 1) to evaluate the impact of c.1-25C>G polymorphism on LRP1 transcriptional activity and expression, and 2) to examine the response of c.1-25C>G LRP1 promoter to LDL and AngII. EMSA and Luciferase assays in HeLa cells showed that -25G promoter has enhanced basal transcriptional activity and specific Sp1/Sp3 binding. hVSMC with GG genotype (GG-hVSMC) had higher LRP1 mRNA and protein levels, respectively than CC genotype (CC-hVSMC). EMSA assays showed that the polymorphism determines scarce amount of SRE-B/SREBP-2 complex formation and the failure of agLDL to further reduce these SRE-B/SREBP-2 complexes. Taken together, these results suggest that c.1-25C>G, by difficulting SREBP-2 binding, prevents SREBP-2 displacement required for LRP1 promoter response to LDL. In contrast, c.1-25C>G strongly favours Sp1/Sp3 binding and AngII-induced activity in Sp1/Sp3 dependent manner in GG-hVSMC. This increase is functionally translated into a higher capacity of GG-hVSMC to become foam cells from agLDL in presence of AngII. These results suggest that c.1-25C>G determines a lack of response to agLDL and an exacerbated response to AngII. It is thus conceivable that the presence of the polymorphism would be easily translated to vascular alterations in the presence of the pro-hypertensive autacoid, AngII.
Collapse
Affiliation(s)
- R Aledo
- Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Autonomous University of Barcelona, Sant Antoni Mª Claret, 167, 08025 Barcelona, Spain
| | - P Costales
- Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Autonomous University of Barcelona, Sant Antoni Mª Claret, 167, 08025 Barcelona, Spain
| | - C Ciudad
- Biochemistry and Molecular Biology Department, School of Pharmacy, IBUB, University of Barcelona, Barcelona, Spain
| | - V Noé
- Biochemistry and Molecular Biology Department, School of Pharmacy, IBUB, University of Barcelona, Barcelona, Spain
| | - V Llorente-Cortes
- Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Autonomous University of Barcelona, Sant Antoni Mª Claret, 167, 08025 Barcelona, Spain.
| | - L Badimon
- Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, IIB-Sant Pau, Autonomous University of Barcelona, Sant Antoni Mª Claret, 167, 08025 Barcelona, Spain
| |
Collapse
|
21
|
Zheng XY, Zhao SP, Yan H. The role of apolipoprotein A5 in obesity and the metabolic syndrome. Biol Rev Camb Philos Soc 2012; 88:490-8. [PMID: 23279260 DOI: 10.1111/brv.12005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 11/10/2012] [Accepted: 11/20/2012] [Indexed: 12/17/2022]
Affiliation(s)
- Xiao-Yan Zheng
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha; 410011; China
| | - Shui-Ping Zhao
- Department of Cardiology; The Second Xiangya Hospital, Central South University; Changsha; 410011; China
| | - Hu Yan
- Institute of Mental Health; The Second Xiangya Hospital, Central South University; Changsha; 410011; China
| |
Collapse
|
22
|
Clemente-Postigo M, Queipo-Ortuño MI, Fernandez-Garcia D, Gomez-Huelgas R, Tinahones FJ, Cardona F. Adipose tissue gene expression of factors related to lipid processing in obesity. PLoS One 2011; 6:e24783. [PMID: 21966368 PMCID: PMC3178563 DOI: 10.1371/journal.pone.0024783] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/17/2011] [Indexed: 12/03/2022] Open
Abstract
Background Adipose tissue lipid storage and processing capacity can be a key factor for obesity-related metabolic disorders such as insulin resistance and diabetes. Lipid uptake is the first step to adipose tissue lipid storage. The aim of this study was to analyze the gene expression of factors involved in lipid uptake and processing in subcutaneous (SAT) and visceral (VAT) adipose tissue according to body mass index (BMI) and the degree of insulin resistance (IR). Methods and Principal Findings VLDL receptor (VLDLR), lipoprotein lipase (LPL), acylation stimulating protein (ASP), LDL receptor-related protein 1 (LRP1) and fatty acid binding protein 4 (FABP4) gene expression was measured in VAT and SAT from 28 morbidly obese patients with Type 2 Diabetes Mellitus (T2DM) or high IR, 10 morbidly obese patients with low IR, 10 obese patients with low IR and 12 lean healthy controls. LPL, FABP4, LRP1 and ASP expression in VAT was higher in lean controls. In SAT, LPL and FABP4 expression were also higher in lean controls. BMI, plasma insulin levels and HOMA-IR correlated negatively with LPL expression in both VAT and SAT as well as with FABP4 expression in VAT. FABP4 gene expression in SAT correlated inversely with BMI and HOMA-IR. However, multiple regression analysis showed that BMI was the main variable contributing to LPL and FABP4 gene expression in both VAT and SAT. Conclusions Morbidly obese patients have a lower gene expression of factors related with lipid uptake and processing in comparison with healthy lean persons.
Collapse
Affiliation(s)
- Mercedes Clemente-Postigo
- Laboratorio de Investigaciones Biomédicas del Hospital Virgen de la Victoria, Málaga (Fundación IMABIS), Spain
| | - Maria Isabel Queipo-Ortuño
- Laboratorio de Investigaciones Biomédicas del Hospital Virgen de la Victoria, Málaga (Fundación IMABIS), Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición, Spain
| | - Diego Fernandez-Garcia
- CIBER Fisiopatología de la Obesidad y la Nutrición, Spain
- Servicio Endocrinología y Nutrición del Hospital Universitario Virgen de la Victoria, Málaga, Spain
| | - Ricardo Gomez-Huelgas
- CIBER Fisiopatología de la Obesidad y la Nutrición, Spain
- Servicio de Medicina Interna del Hospital Regional Carlos Haya, Spain
| | - Francisco J. Tinahones
- CIBER Fisiopatología de la Obesidad y la Nutrición, Spain
- Servicio Endocrinología y Nutrición del Hospital Universitario Virgen de la Victoria, Málaga, Spain
| | - Fernando Cardona
- Laboratorio de Investigaciones Biomédicas del Hospital Virgen de la Victoria, Málaga (Fundación IMABIS), Spain
- CIBER Fisiopatología de la Obesidad y la Nutrición, Spain
- * E-mail:
| |
Collapse
|
23
|
Bosco D, Fava A, Plastino M, Montalcini T, Pujia A. Possible implications of insulin resistance and glucose metabolism in Alzheimer's disease pathogenesis. J Cell Mol Med 2011; 15:1807-21. [PMID: 21435176 PMCID: PMC3918038 DOI: 10.1111/j.1582-4934.2011.01318.x] [Citation(s) in RCA: 196] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2010] [Accepted: 03/17/2011] [Indexed: 01/21/2023] Open
Abstract
Type 2 diabetes mellitus (DM) appears to be a significant risk factor for Alzheimer disease (AD). Insulin and insulin-like growth factor-1 (IGF-1) also have intense effects in the central nervous system (CNS), regulating key processes such as neuronal survival and longevity, as well as learning and memory. Hyperglycaemia induces increased peripheral utilization of insulin, resulting in reduced insulin transport into the brain. Whereas the density of brain insulin receptor decreases during age, IGF-1 receptor increases, suggesting that specific insulin-mediated signals is involved in aging and possibly in cognitive decline. Molecular mechanisms that protect CNS neurons against β-amyloid-derived-diffusible ligands (ADDL), responsible for synaptic deterioration underlying AD memory failure, have been identified. The protection mechanism does not involve simple competition between ADDLs and insulin, but rather it is signalling dependent down-regulation of ADDL-binding sites. Defective insulin signalling make neurons energy deficient and vulnerable to oxidizing or other metabolic insults and impairs synaptic plasticity. In fact, destruction of mitochondria, by oxidation of a dynamic-like transporter protein, may cause synapse loss in AD. Moreover, interaction between Aβ and τ proteins could be cause of neuronal loss. Hyperinsulinaemia as well as complete lack of insulin result in increased τ phosphorylation, leading to an imbalance of insulin-regulated τ kinases and phosphatates. However, amyloid peptides accumulation is currently seen as a key step in the pathogenesis of AD. Inflammation interacts with processing and deposit of β-amyloid. Chronic hyperinsulinemia may exacerbate inflammatory responses and increase markers of oxidative stress. In addition, insulin appears to act as 'neuromodulator', influencing release and reuptake of neurotransmitters, and improving learning and memory. Thus, experimental and clinical evidence show that insulin action influences cerebral functions. In this paper, we reviewed several mechanisms by which insulin may affect pathophysiology in AD.
Collapse
Affiliation(s)
- Domenico Bosco
- Department of Neuroscience, 'S. Giovanni di Dio' Hospital, Via Largo Bologna, Crotone, Italy.
| | | | | | | | | |
Collapse
|
24
|
Dieckmann M, Dietrich MF, Herz J. Lipoprotein receptors--an evolutionarily ancient multifunctional receptor family. Biol Chem 2011; 391:1341-63. [PMID: 20868222 DOI: 10.1515/bc.2010.129] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The evolutionarily ancient low-density lipoprotein (LDL) receptor gene family represents a class of widely expressed cell surface receptors. Since the dawn of the first primitive multicellular organisms, several structurally and functionally distinct families of lipoprotein receptors have evolved. In accordance with the now obsolete 'one-gene-one-function' hypothesis, these cell surface receptors were originally perceived as mere transporters of lipoproteins, lipids, and nutrients or as scavenger receptors, which remove other kinds of macromolecules, such as proteases and protease inhibitors from the extracellular environment and the cell surface. This picture has since undergone a fundamental change. Experimental evidence has replaced the perception that these receptors serve merely as cargo transporters. Instead it is now clear that the transport of macromolecules is inseparably intertwined with the molecular machinery by which cells communicate with each other. Lipoprotein receptors are essentially sensors of the extracellular environment that participate in a wide range of physiological processes by physically interacting and coevolving with primary signal transducers as co-regulators. Furthermore, lipoprotein receptors modulate cellular trafficking and localization of the amyloid precursor protein (APP) and the β-amyloid peptide (Aβ), suggesting a role in the pathogenesis of Alzheimer's disease. Moreover, compelling evidence shows that LDL receptor family members are involved in tumor development and progression.
Collapse
Affiliation(s)
- Marco Dieckmann
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9046, USA
| | | | | |
Collapse
|
25
|
Jedrychowski MP, Gartner CA, Gygi SP, Zhou L, Herz J, Kandror KV, Pilch PF. Proteomic analysis of GLUT4 storage vesicles reveals LRP1 to be an important vesicle component and target of insulin signaling. J Biol Chem 2009; 285:104-14. [PMID: 19864425 DOI: 10.1074/jbc.m109.040428] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Insulin stimulates the translocation of intracellular GLUT4 to the plasma membrane where it functions in adipose and muscle tissue to clear glucose from circulation. The pathway and regulation of GLUT4 trafficking are complicated and incompletely understood and are likely to be contingent upon the various proteins other than GLUT4 that comprise and interact with GLUT4-containing vesicles. Moreover, not all GLUT4 intracellular pools are insulin-responsive as some represent precursor compartments, thus posing a biochemical challenge to the purification and characterization of their content. To address these issues, we immunodepleted precursor GLUT4-rich vesicles and then immunopurified GLUT4 storage vesicle (GSVs) from primary rat adipocytes and subjected them to semi-quantitative and quantitative proteomic analysis. The purified vesicles translocate to the cell surface almost completely in response to insulin, the expected behavior for bona fide GSVs. In total, over 100 proteins were identified, about 50 of which are novel in this experimental context. LRP1 (low density lipoprotein receptor-related protein 1) was identified as a major constituent of GSVs, and we show it interacts with the lumenal domains of GLUT4 and other GSV constituents. Its cytoplasmic tail interacts with the insulin-signaling pathway target, AS160 (Akt substrate of 160 kDa). Depletion of LRP1 from 3T3-L1 adipocytes reduces GLUT4 expression and correspondingly results in decreased insulin-stimulated 2-[(3)H]deoxyglucose uptake. Furthermore, adipose-specific LRP1 knock-out mice also exhibit decreased GLUT4 expression. These findings suggest LRP1 is an important component of GSVs, and its expression is needed for the formation of fully functional GSVs.
Collapse
Affiliation(s)
- Mark P Jedrychowski
- Department of Biochemistry, Boston University Medical School, Boston, Massachusetts 02118, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
LRP1 receptor controls adipogenesis and is up-regulated in human and mouse obese adipose tissue. PLoS One 2009; 4:e7422. [PMID: 19823686 PMCID: PMC2758584 DOI: 10.1371/journal.pone.0007422] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 09/22/2009] [Indexed: 11/19/2022] Open
Abstract
The cell surface low-density lipoprotein receptor-related protein 1, LRP1, plays a major role in lipid metabolism. The question that remains open concerns the function of LRP1 in adipogenesis. Here, we show that LRP1 is highly expressed in murine preadipocytes as well as in primary culture of human adipocytes. Moreover, LRP1 remains abundantly synthesised during mouse and human adipocyte differentiation. We demonstrate that LRP1 silencing in 3T3F442A murine preadipocytes significantly inhibits the expression of PPARgamma, HSL and aP2 adipocyte differentiation markers after adipogenesis induction, and leads to lipid-depleted cells. We further show that the absence of lipids in LRP1-silenced preadipocytes is not caused by lipolysis induction. In addition, we provide the first evidences that LRP1 is significantly up-regulated in obese C57BI6/J mouse adipocytes and obese human adipose tissues. Interestingly, silencing of LRP1 in fully-differentiated adipocytes also reduces cellular lipid level and is associated with an increase of basal lipolysis. However, the ability of mature adipocytes to induce lipolysis is independent of LRP1 expression. Altogether, our findings highlight the dual role of LRP1 in the control of adipogenesis and lipid homeostasis, and suggest that LRP1 may be an important therapeutic target in obesity.
Collapse
|
27
|
Bagdade J, Knight-Gibson C, Quiroga C, Jacobson M, Lee D. Distribution of immunochemically defined apoB-containing lipoprotein subclasses in T1D. Diabetes Res Clin Pract 2009; 85:265-71. [PMID: 19619912 DOI: 10.1016/j.diabres.2009.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 06/15/2009] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Young women with T1D develop CHD without any apparent lipid related risk factor. To determine whether abnormalities in the five immunochemically defined apoB-containing lipoprotein subclasses might influence this risk, we have measured these subclasses in T1D subjects. RESEARCH DESIGN AND METHODS ApoA- and B-containing lipoprotein subclasses were isolated immunochemically and quantitated in 37 young (mean age 31.8+/-12.7 years) otherwise healthy subjects (16 males; 21 females) with T1D (HbA1c=8.2+/-1.7%) treated conventionally with subcutaneous insulin. RESULTS T1D women had significantly more cholesterol-rich Lp-B particles (T1D: 55.9+/-4.5 vs. control 46.8+/-11.1mg apoB/dL; p<.01) which were over-represented in the apolipoprotein B particle pool (apoB/Lp-B: T1D: 1.49+/-.19 vs. control: 1.67+/-.22; p<.01). HbA1c correlated with Lp-B (r=0.60; p<.001) and the mass of apoB subclasses containing apoC-III (r=0.69; p<.001). CONCLUSIONS Women with T1D have a disturbance in the transport of Lp-B particles manifested by both an absolute and relative increase in their number that may result from portal hypoinsulinemia and reduced LDL B,E receptor activity. This pathway may enhance CHD risk in T1D women when of LDL and apoB levels are normal.
Collapse
Affiliation(s)
- John Bagdade
- Department of Medicine, Oregon Health & Sciences University, Portland, OR, United States.
| | | | | | | | | |
Collapse
|
28
|
Santos RD. Commentary on the study of Laatsch et al. “Insulin stimulates hepatic low density lipoprotein receptor-related protein 1 (LRP1) to increase postprandial lipoprotein clearance”. Atherosclerosis 2009; 204:112-3. [DOI: 10.1016/j.atherosclerosis.2008.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Accepted: 10/17/2008] [Indexed: 11/30/2022]
|
29
|
Interaction between remnant-like lipoprotein particles and adipocytes. Int J Cardiol 2009; 133:3-7. [PMID: 19042042 DOI: 10.1016/j.ijcard.2008.10.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 10/25/2008] [Indexed: 11/24/2022]
Abstract
Inflammation plays a pivotal role in the pathophysiology of atherosclerosis. Remnant-like lipoprotein particles (RLPs) have been implicated as potentially atherogenic lipoproteins. RLPs can induce a pronounced inflammatory response especially during the postprandial phase. Increasing evidence demonstrates that adipose tissue may be a significant contributor to the increased systemic inflammation through secretion of various proinflammatory adipocytokines. In addition, adipocytes may potentially regulate RLPs metabolism. Therefore, we hypothesized that there might be an interaction between RLPs and adipocytes.
Collapse
|
30
|
Insulin stimulates hepatic low density lipoprotein receptor-related protein 1 (LRP1) to increase postprandial lipoprotein clearance. Atherosclerosis 2008; 204:105-11. [PMID: 18834984 DOI: 10.1016/j.atherosclerosis.2008.07.046] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 07/28/2008] [Accepted: 07/30/2008] [Indexed: 01/09/2023]
Abstract
BACKGROUND While the role of insulin in glucose uptake and its aberration in diabetes are well established, the effect of insulin on lipoprotein clearance in the postprandial phase is not yet fully understood. The dietary lipids are carried in chylomicron remnants (CR) which are taken up into the liver mainly via LDLR-related protein 1 (LRP1). In this study, the effect of insulin on LRP1-mediated hepatic CR uptake was investigated. METHODS The study was based on determining the subcellular localisation of LRP1 by subcellular fractionation and immunofluorescence microscopy and correlating those findings with the hepatic uptake of fluorescently or radioactively labelled LRP1-specific ligands and CR in hepatoma cells, primary hepatocytes and mouse models. RESULTS AND CONCLUSION In vitro and in vivo, insulin stimulated the translocation of hepatic LRP1 from intracellular vesicles to the plasma membrane, which correlates with an increased uptake of LRP1-specific ligands. In wild-type mice, a glucose-induced insulin response increased the hepatic uptake of LRP1 ligands while in leptin-deficient obese mice (ob/ob), which are characterised by hepatic insulin resistance, insulin-inducible LRP1 ligand uptake was abolished. Finally, upon hepatic LRP1 knockdown, insulin no longer significantly enhanced CR uptake into the liver. The insulin-induced LRP1-mediated CR uptake, as demonstrated here, suggests that impaired hepatic LRP1 translocation can contribute to the postprandial lipaemia in insulin resistance.
Collapse
|
31
|
Lillis AP, Van Duyn LB, Murphy-Ullrich JE, Strickland DK. LDL receptor-related protein 1: unique tissue-specific functions revealed by selective gene knockout studies. Physiol Rev 2008; 88:887-918. [PMID: 18626063 DOI: 10.1152/physrev.00033.2007] [Citation(s) in RCA: 520] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The LDL receptor-related protein (originally called LRP, but now referred to as LRP1) is a large endocytic receptor that is widely expressed in several tissues. LRP1 is a member of the LDL receptor family that plays diverse roles in various biological processes including lipoprotein metabolism, degradation of proteases, activation of lysosomal enzymes, and cellular entry of bacterial toxins and viruses. Deletion of the LRP1 gene leads to lethality in mice, revealing a critical, but as of yet, undefined role in development. Tissue-specific gene deletion studies reveal an important contribution of LRP1 in the vasculature, central nervous system, macrophages, and adipocytes. Three important properties of LRP1 dictate its diverse role in physiology: 1) its ability to recognize more than 30 distinct ligands, 2) its ability to bind a large number of cytoplasmic adaptor proteins via determinants located on its cytoplasmic domain in a phosphorylation-specific manner, and 3) its ability to associate with and modulate the activity of other transmembrane receptors such as integrins and receptor tyrosine kinases.
Collapse
Affiliation(s)
- Anna P Lillis
- Center for Vascular and Inflammatory Diseases and Department of Surgery and Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | | | | |
Collapse
|
32
|
Hofmann SM, Zhou L, Perez-Tilve D, Greer T, Grant E, Wancata L, Thomas A, Pfluger PT, Basford JE, Gilham D, Herz J, Tschöp MH, Hui DY. Adipocyte LDL receptor-related protein-1 expression modulates postprandial lipid transport and glucose homeostasis in mice. J Clin Invest 2008; 117:3271-82. [PMID: 17948131 DOI: 10.1172/jci31929] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 08/01/2007] [Indexed: 12/13/2022] Open
Abstract
Diet-induced obesity and its serious consequences such as diabetes, cardiovascular disease, and cancer are rapidly becoming a major global health threat. Therefore, understanding the cellular and molecular mechanisms by which dietary fat causes obesity and diabetes is of paramount importance in order to identify preventive and therapeutic strategies. Increased dietary fat intake results in high plasma levels of triglyceride-rich lipoproteins (TGRL). Tissue uptake of TGRL has been shown to promote glucose intolerance. We generated mice with an adipocyte-specific inactivation of the multifunctional receptor LDL receptor-related protein-1 (LRP1) to determine its role in mediating the effects of TGRL on diet-induced obesity and diabetes. Knockout mice displayed delayed postprandial lipid clearance, reduced body weight, smaller fat stores, lipid-depleted brown adipocytes, improved glucose tolerance, and elevated energy expenditure due to enhanced muscle thermogenesis. We further demonstrated that inactivation of adipocyte LRP1 resulted in resistance to dietary fat-induced obesity and glucose intolerance. These findings identify LRP1 as a critical regulator of adipocyte energy homeostasis, where functional disruption leads to reduced lipid transport, increased insulin sensitivity, and muscular energy expenditure.
Collapse
Affiliation(s)
- Susanna M Hofmann
- Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45237, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Pilch PF. The mass action hypothesis: formation of Glut4 storage vesicles, a tissue-specific, regulated exocytic compartment. Acta Physiol (Oxf) 2008; 192:89-101. [PMID: 18171432 DOI: 10.1111/j.1748-1716.2007.01788.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Insulin stimulates glucose uptake into the target tissues of fat and muscle by recruiting or translocating Glut4 glucose transport proteins to their functional location at the cell surface. In the basal state, Glut4 is sequestered intracellularly in several vesicular compartments, one of which has come to be known as Glut4 storage vesicles (GSVs). The GSVs represent a tissue-specific compartment that is an ultimate target of the insulin signalling cascade. Glut4 translocation has been extensively studied because of its intrinsic scientific importance to cell biology as well as its relevance to the pathology of type 2 diabetes mellitus. I review herein the ontogeny of GSVs and their composition as it relates to a tissue-specific, hormone-sensitive exocytic compartment and propose a mechanism for their formation.
Collapse
Affiliation(s)
- P F Pilch
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
| |
Collapse
|
34
|
Prawitt J, Niemeier A, Kassem M, Beisiegel U, Heeren J. Characterization of lipid metabolism in insulin-sensitive adipocytes differentiated from immortalized human mesenchymal stem cells. Exp Cell Res 2007; 314:814-24. [PMID: 18068701 DOI: 10.1016/j.yexcr.2007.11.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 11/01/2007] [Accepted: 11/14/2007] [Indexed: 11/28/2022]
Abstract
There is a great demand for cell models to study human adipocyte function. Here we describe the adipogenic differentiation of a telomerase-immortalized human mesenchymal stem cell line (hMSC-Tert) that maintains numerous features of terminally differentiated adipocytes even after prolonged withdrawal of the peroxisome proliferator activated receptor gamma (PPARgamma) agonist rosiglitazone. Differentiated hMSC-Tert developed the characteristic monolocular phenotype of mature adipocytes. The expression of adipocyte specific markers was highly increased during differentiation. Most importantly, the presence of the PPARgamma agonist rosiglitazone was not required for the stable expression of lipoprotein lipase, adipocyte fatty acid binding protein and perilipin on mRNA and protein levels. Adiponectin expression was post-transcriptionally down-regulated in the absence of rosiglitazone. Insulin sensitivity as measured by insulin-induced phosphorylation of Akt and S6 ribosomal protein was also independent of rosiglitazone. In addition to commonly used adipogenic markers, we investigated further PPARgamma-stimulated proteins with a role in lipid metabolism. We observed an increase of lipoprotein receptor (VLDLR, LRP1) and apolipoprotein E expression during differentiation. Despite this increased expression, the receptor-mediated endocytosis of lipoproteins was decreased in differentiated adipocytes, suggesting that these proteins may have an additional function in adipose tissue beyond lipoprotein uptake.
Collapse
Affiliation(s)
- Janne Prawitt
- Department of Biochemistry and Molecular Biology II: Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | | | | | | |
Collapse
|
35
|
Tamaki C, Ohtsuki S, Terasaki T. Insulin facilitates the hepatic clearance of plasma amyloid beta-peptide (1 40) by intracellular translocation of low-density lipoprotein receptor-related protein 1 (LRP-1) to the plasma membrane in hepatocytes. Mol Pharmacol 2007; 72:850-5. [PMID: 17609417 DOI: 10.1124/mol.107.036913] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The hepatic clearance of amyloid beta-peptide (1-40) [Abeta(1-40)] from plasma, which is largely mediated by low-density lipoprotein receptor-related protein (LRP-1), is suggested to play a role in preventing Abeta(1-40) accumulation in the brain. Epidemiological investigations suggest a high incidence of cerebral Abeta deposition in insulin-resistant type II diabetes mellitus. The purpose of this study was to clarify the effect of insulin on the hepatic clearance of Abeta(1-40). LRP-1 expression on the hepatic plasma membrane was increased in a time-dependent manner by portal infusion of insulin and was 2.2-fold greater than that in nontreated controls after a 10-min infusion, whereas the expression in whole lysate was not affected by insulin treatment. The apparent hepatic uptake of [(125)I]Abeta(1-40) was also induced by insulin in a time-dependent manner. The increase in [(125)I]Abeta(1-40) uptake by insulin was concentration-dependent (EC(50) = 230 pM) and was completely abolished by receptor-associated protein (2 muM), an LRP-1 inhibitor. In conclusion, plasma insulin facilitates LRP-1 translocation to the hepatic plasma membrane from the intracellular pool, resulting in significant enhancement of hepatic Abeta(1-40) uptake from the circulating blood. The presently proposed mechanism would explain the epidemiological results demonstrating that type II diabetes mellitus is a risk factor of Alzheimer's disease.
Collapse
Affiliation(s)
- Chihiro Tamaki
- Department of Molecular Biopharmacy and Genetics, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | | | | |
Collapse
|
36
|
Gao J, Katagiri H, Ishigaki Y, Yamada T, Ogihara T, Imai J, Uno K, Hasegawa Y, Kanzaki M, Yamamoto TT, Ishibashi S, Oka Y. Involvement of apolipoprotein E in excess fat accumulation and insulin resistance. Diabetes 2007; 56:24-33. [PMID: 17192461 DOI: 10.2337/db06-0144] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Although apolipoprotein E (apoE) is well known to play a major role in lipid metabolism, its role in glucose and energy homeostasis remains unclear. Herein, we established apoE-deficient genetically obese Ay (apoE(-/-);Ay/+) mice. ApoE deficiency in Ay mice prevented the development of obesity, with decreased fat accumulation in the liver and adipose tissues. ApoE(-/-);Ay/+ mice exhibited better glucose tolerance than apoE(+/+);Ay/+ mice. Insulin tolerance testing and hyperinsulinemic-euglycemic clamp study revealed marked improvement of insulin sensitivity, despite increased plasma free fatty acid levels. These metabolic phenotypes were reversed by adenoviral replenishment of apoE protein, indicating circulating apoE to be involved in increased adiposity and obesity-related metabolic disorders. Uptake of apoE-lacking VLDL into the liver and adipocytes was markedly inhibited, but adipocytes in apoE(-/-);Ay/+ mice exhibited normal differentiation, suggesting that apoE-dependent VLDL transport is involved in the development of obesity, i.e., surplus fat accumulation. Interestingly, apoE(-/-);Ay/+ mice exhibited decreased food intake and increased energy expenditure. Pair-feeding experiments indicate these phenomena to both contribute to the obesity-resistant phenotypes associated with apoE deficiency. Thus, apoE is involved in maintaining energy homeostasis. ApoE-dependent excess fat accumulation is a promising therapeutic target for the metabolic syndrome.
Collapse
Affiliation(s)
- Junhong Gao
- Division of Molecular Metabolism and Diabetes, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Degrace P, Moindrot B, Mohamed I, Gresti J, Du ZY, Chardigny JM, Sébédio JL, Clouet P. Upregulation of liver VLDL receptor and FAT/CD36 expression in LDLR-/- apoB100/100 mice fed trans-10,cis-12 conjugated linoleic acid. J Lipid Res 2006; 47:2647-55. [PMID: 16957181 DOI: 10.1194/jlr.m600140-jlr200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study explores the mechanisms responsible for the fatty liver setup in mice fed trans-10,cis-12 conjugated linoleic acid (t10c12 CLA), hypothesizing that an induction of low density lipoprotein receptor (LDLR) expression is associated with lipid accumulation. To this end, the effects of t10c12 CLA treatment on lipid parameters, serum lipoproteins, and expression of liver lipid receptors were measured in LDLR(-/-) apoB(100/100) mice as a model of human familial hypercholesterolemia itself depleted of LDLR. Mice were fed t10c12 CLA over 2 or 4 weeks. We first observed that the treatment induced liver steatosis, even in the absence of LDLR. Mice treated for 2 weeks exhibited hypertriglyceridemia with high levels of VLDL and HDL, whereas a 4 week treatment inversely induced a reduction of serum triglycerides (TGs), essentially through a decrease in VLDL levels. In the absence of LDLR, the mRNA levels of other proteins, such as VLDL receptor, lipoprotein lipase, and fatty acid translocase, usually not expressed in the liver, were upregulated, suggesting their involvement in the steatosis setup and lipoprotein clearance. The data also suggest that the TG-lowering effect induced by t10c12 CLA treatment was attributable to both the reduction of circulating free fatty acids in response to the severe lipoatrophy and the high capacity of liver to clear off plasma lipids.
Collapse
Affiliation(s)
- Pascal Degrace
- Unité Propre de Recherche de l'Enseignement Supérieur, Lipides et Nutrition EA2422, Faculté des Sciences Gabriel, Université de Bourgogne, 21000 Dijon, France.
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Moreno JA, Pérez-Jiménez F, Marín C, Pérez-Martínez P, Moreno R, Gómez P, Jiménez-Gómez Y, Paniagua JA, Lairon D, López-Miranda J. The apolipoprotein E gene promoter (-219G/T) polymorphism determines insulin sensitivity in response to dietary fat in healthy young adults. J Nutr 2005; 135:2535-40. [PMID: 16251607 DOI: 10.1093/jn/135.11.2535] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insulin sensitivity (IS) is determined by genetic and environmental factors, including diet. The apoE gene promoter -219G/T polymorphism is associated with coronary heart disease and increased postprandial triacylglycerol-rich lipoprotein concentration, circumstances related to insulin resistance. Thus, our aim was to determine whether this polymorphism modified the IS response to dietary fat in healthy young adults. Volunteers (n = 43) with the apoE3/E3 genotype (8 GG, 25 GT and 10 TT) completed 3 dietary periods, each lasting 4 wk. They first consumed a SFA-rich diet [38% fat (% of energy in the total diet), 20% SFA (% of energy in the total diet)], and then, in a randomized, crossover design, a carbohydrate (CHO)-rich diet (30% fat, 55% CHO) or a monounsaturated fatty acid (MUFA)-rich diet (38% fat, 22% MUFA). After each diet period, we investigated peripheral IS using the insulin suppression test. The steady-state plasma glucose (SSPG) concentration was lower (P < 0.05) in GG subjects than in GT and TT individuals, regardless of the diet consumed. Significant diet x genotype interactions were found for SSPG and plasma nonesterified FFA (NEFA) concentrations. Thus, the shift from the SFA-rich diet to the MUFA- or CHO-rich diets decreased (P < 0.05) the SSPG and NEFA concentrations in GG and GT, but not in TT subjects. In conclusion, carriers of the -219T allele are less insulin sensitive than GG individuals. Furthermore, only carriers of the -219G allele have improved IS when MUFA- or CHO-rich diets are consumed instead of a SFA-rich diet.
Collapse
Affiliation(s)
- Juan Antonio Moreno
- Lipids and Atherosclerosis Research Unit, Hospital Universitario Reina Sofía, Córdoba, Spain
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Zhang H, Links PH, Ngsee JK, Tran K, Cui Z, Ko KWS, Yao Z. Localization of low density lipoprotein receptor-related protein 1 to caveolae in 3T3-L1 adipocytes in response to insulin treatment. J Biol Chem 2003; 279:2221-30. [PMID: 14593097 DOI: 10.1074/jbc.m310679200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The insulin-induced translocation of low density lipoprotein receptor-related protein 1 (LRP1) from intracellular membranes to the cell surface in 3T3-L1 adipocytes was differentiation-dependent and did not occur in 3T3-L1 fibroblasts. Prompted by findings that the plasma membrane of 3T3-L1 adipocytes was rich in caveolae, we determined whether LRP1 became caveolae-associated upon insulin stimulation. The caveolae domain was isolated by the well characterized detergent solubilization and sucrose density ultracentrifugation methodology. Under basal conditions, only a trace amount of LRP1 was caveolae-associated despite the markedly elevated caveolin-1 and caveolae after adipocytic cell differentiation. Upon insulin treatment, the amount of LRP1 associated with caveolae was increased by 4-fold within 10 min, which was blocked completely by pretreatment with wortmannin prior to insulin. The caveolar localization of LRP1 in adipocytes was specific to insulin; treatment with platelet-derived growth factor-bb isoform did not promote but rather decreased caveolar localization of LRP1 below basal levels. The insulin-induced caveolar localization of LRP1 was also observed in 3T3-L1 fibroblasts where translocation of LRP1 from intracellular membranes to the cell surface was absent, suggesting that association of LRP1 with caveolae was achieved, at least in part, through lateral transmigration along the plane of plasma membranes. Immunocytochemistry studies revealed partial co-localization of LRP1 (either endogenous LRP1 or an epitope-tagged minireceptor) with caveolin-1 in cells treated with insulin, which was confirmed by co-immunoprecipitation of LRP1 with caveolin-1 in cells treated with insulin but not platelet-derived growth factor-bb. These results suggest that the localization of LRP1 to caveolae responds selectively to extracellular signals.
Collapse
Affiliation(s)
- Hongyu Zhang
- Lipoprotein and Atherosclerosis Group, University of Ottawa Heart Institute, Ottawa K1Y 4W7, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
40
|
Chiba T, Nakazawa T, Yui K, Kaneko E, Shimokado K. VLDL induces adipocyte differentiation in ApoE-dependent manner. Arterioscler Thromb Vasc Biol 2003; 23:1423-9. [PMID: 12842848 DOI: 10.1161/01.atv.0000085040.58340.36] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To clarify the role of very low density lipoprotein (VLDL) and apolipoprotein E (apoE) in adipogenesis, we studied newly developed hyperlipidemic obese (ob/ob;apoE-/-) mice. Because hydrolysis of VLDL is believed to be the major source of adipogenic free fatty acids, a higher plasma level of VLDL in these mice should exaggerate obesity. METHODS AND RESULTS When fed a high-fat, high-cholesterol diet, ob/ob;apoE-/- mice did not show increased body weight or an increased amount of adipose tissue in spite of increased plasma VLDL levels, whereas ob/ob mice showed an increased body weight and amount of adipose tissue, suggesting that there is a novel apoE-dependent pathway for adipogenesis. In vitro experiments using bone marrow stromal cells and 3T3-L1 cells confirmed this notion. ApoE-deficient VLDL did not induce adipogenesis, whereas normal VLDL induced adipogenesis in these cells. The incubation of apoE-deficient VLDL with recombinant human apoE restored its adipogenic activity. Tetrahydrolipstatin, a lipoprotein lipase inhibitor, did not affect the adipogenic activity of VLDL, suggesting that hydrolysis of VLDL did not play a major role in its effects. In fact, lipid components of VLDL or free fatty acids induced only partial adipogenesis. CONCLUSIONS Our findings indicate that VLDL induces adipogenesis in an apoE-dependent manner both in vitro and in vivo.
Collapse
Affiliation(s)
- Tsuyoshi Chiba
- Tokyo Medical and Dental University Graduate School, Vascular Medicine and Geriatrics, Tokyo, Japan
| | | | | | | | | |
Collapse
|
41
|
Craft S, Asthana S, Cook DG, Baker LD, Cherrier M, Purganan K, Wait C, Petrova A, Latendresse S, Watson GS, Newcomer JW, Schellenberg GD, Krohn AJ. Insulin dose-response effects on memory and plasma amyloid precursor protein in Alzheimer's disease: interactions with apolipoprotein E genotype. Psychoneuroendocrinology 2003; 28:809-22. [PMID: 12812866 DOI: 10.1016/s0306-4530(02)00087-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In previous studies, adults with Alzheimer's disease (AD) showed memory enhancement when plasma insulin levels were raised to 85 microU/ml, whereas normal adults' memory was unchanged. Degree of memory enhancement was also related to apolipoprotein E (apoE) genotype status for AD patients. Response differences between normal and AD groups could reflect dose-response differences for insulin. To examine this question, 22 adults with AD and 15 normal adults received five doses of insulin on separate days in counterbalanced order, resulting in five plasma insulin levels (10, 25, 35, 85 and 135 microU/ml), while plasma glucose levels of ~100 mg/dl were maintained. Cognitive performance and plasma APP levels were measured after 120 min of infusion. Relative to baseline, AD patients who were not apoE- epsilon 4 homozygotes had improved memory at higher insulin levels of 35 and 85 microuU/ml, whereas normal adults and AD patients who were epsilon 4 homozygotes showed improved memory at insulin levels of 25 microU/ml. Normal adults' memory was also improved at insulin levels of 85 microU/ml. Plasma APP was lowered for adults with AD without the epsilon 4 allele at higher levels (85 microU/ml) than for normal adults and epsilon 4 homozygotes, who showed decreased APP at the 35 microU/ml level. AD patients with a single epsilon 4 allele showed a different pattern of insulin effects on APP than did other subjects. In general, few effects of insulin were seen at the highest dose for any subject group. These results support a role for insulin in normal memory and APP modulation that follows a curvilinear response pattern, and suggest that AD patients who are not epsilon 4 homozygotes have reduced sensitivity to insulin that may interfere with such modulation.
Collapse
Affiliation(s)
- Suzanne Craft
- Geriatric Research, Education, and Clinical Center, Veteran Affairs Puget Sound Health Care System, 1660 South Columbian Way, Seattle, WA 98108, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Gauthier A, Vassiliou G, Benoist F, McPherson R. Adipocyte low density lipoprotein receptor-related protein gene expression and function is regulated by peroxisome proliferator-activated receptor gamma. J Biol Chem 2003; 278:11945-53. [PMID: 12551936 DOI: 10.1074/jbc.m212989200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The alpha(2)-macroglobulin receptor/low density lipoprotein receptor-related protein (LRP) is a large multifunctional receptor that interacts with a variety of molecules. It is implicated in biologically important processes such as lipoprotein metabolism, neurological function, tissue remodeling, protease complex clearance, and cell signal transduction. However, the regulation of LRP gene expression remains largely unknown. In this study, we have analyzed 2 kb of the 5'-flanking region of the LRP gene and identified a predicted peroxisome proliferator response element (PPRE) from -1185 to -1173. Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands such as fatty acids and rosiglitazone increased functional cell surface LRP by 1.5-2.0-fold in primary human adipocytes and in the SW872 human liposarcoma cell line as assessed by activated alpha(2)-macroglobulin binding and degradation. These agents were found to increase LRP transcription. Gel shift analysis of the putative PPRE demonstrated direct binding of PPARgamma/retinoid X receptor alpha heterodimers to the PPRE in the LRP gene. Furthermore, these heterodimers could no longer interact with a mutated PPRE probe. The isolated promoter was functional in SW872 cells, and its activity was increased by 1.5-fold with the addition of rosiglitazone. Furthermore, the isolated response element was similarly responsive to rosiglitazone when placed upstream of an ideal promoter. Mutagenesis of the predicted PPRE abolished the ability of this construct to respond to rosiglitazone. These data demonstrate that fatty acids and rosiglitazone directly stimulate transcription of the LRP gene through activation of PPARgamma and increase functional LRP expression.
Collapse
MESH Headings
- Adipocytes/cytology
- Adipocytes/physiology
- Dimerization
- Enhancer Elements, Genetic/physiology
- Fibrinolytic Agents/pharmacology
- Gene Expression/drug effects
- Gene Expression/physiology
- Humans
- Ligands
- Liposarcoma
- Luciferases/genetics
- Mutagenesis/physiology
- Promoter Regions, Genetic/physiology
- RNA, Messenger/metabolism
- Receptors, Cell Surface/genetics
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, LDL/genetics
- Receptors, Retinoic Acid/chemistry
- Receptors, Retinoic Acid/metabolism
- Response Elements/genetics
- Retinoid X Receptors
- Rosiglitazone
- Thiazoles/pharmacology
- Thiazolidinediones
- Transcription Factors/chemistry
- Transcription Factors/metabolism
- Transcriptional Activation/drug effects
- Transcriptional Activation/physiology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- Andre Gauthier
- Lipoprotein and Atherosclerosis Group, University of Ottawa Heart Institute, Ottawa K1Y 4W7, Canada
| | | | | | | |
Collapse
|
43
|
Boucher P, Ducluzeau PH, Davelu P, Andreelli F, Vallier P, Riou JP, Laville M, Vidal H. Expression and regulation by insulin of low-density lipoprotein receptor-related protein mRNA in human skeletal muscle. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1588:226-31. [PMID: 12393177 DOI: 10.1016/s0925-4439(02)00169-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Evidence suggests that increased hydrolysis and/or uptake of triglyceride-rich lipoprotein particles in skeletal muscle can be involved in insulin resistance. We determined the steady state mRNA levels of the low-density lipoprotein-related receptor (LRP) and lipoprotein lipase (LPL) in skeletal muscle of eight healthy lean control subjects, eight type 2 diabetic patients and eight nondiabetic obese individuals. The regulation by insulin of LRP and LPL mRNA expression was also investigated in biopsies taken before and at the end of a 3 h euglycemic hyperinsulinemic clamp (insulinemia of about 1 nM). LRP mRNA was expressed in human skeletal muscle (1.3+/-0.1 amol/microg total RNA in control subjects). Type 2 diabetic patients, but not nondiabetic obese subjects, were characterized by a reduced expression of LRP (0.8+/-0.2 and 1.3+/-0.3 amol/microg total RNA in diabetic and obese patients, respectively; P<0.05 in diabetic vs. control subjects). Insulin infusion decreased LRP mRNA levels in muscle of the control subjects but not in muscle of type 2 diabetic and nondiabetic obese patients. Similar results were found when investigating the regulation of the expression of LPL. Taken together, these results did not support the hypothesis that a higher capacity for clearance or hydrolysis of circulating triglycerides in skeletal muscle is present during obesity- or type 2 diabetes-associated insulin resistance.
Collapse
|
44
|
Jo I, Im HM, Shin HJ, Won Cho K, Jung M, Kim SD, Kim Jeong J, Ahn Jo S. Serum deprivation increases the expression of low density lipoprotein receptor-related protein in primary cultured rat astrocytes. Biochem Biophys Res Commun 2002; 299:102-8. [PMID: 12435395 DOI: 10.1016/s0006-291x(02)02599-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The low density lipoprotein receptor (LDLR)-related protein (LRP) is a multifunctional receptor which mediates the endocytic uptake of several ligands implicated in Alzheimer's disease pathophysiology. Although LRP, as a member of the LDLR family, is likely to be regulated in response to various cellular stresses, this regulation has not been fully understood yet. In the present study we studied the regulation of LRP expression in primary cultured rat astrocytes in response to serum deprivation as a general cellular stress. A significant increase in LRP expression was detected after serum deprivation and this increase was blocked by treatment of U0126, an inhibitor of MAP kinase. This serum deprivation action was partially reversed by either serum or D-glucose supplementation, but further augmented by glutamine. This result contrasted with a finding that glutamine suppressed gadd153 protein induced by serum deprivation. Taken together, the present data suggest that serum deprivation induces dramatically LRP expression in astrocytes partly by MAPK signaling pathways and by signaling pathways apparently distinct from gadd153 induction.
Collapse
Affiliation(s)
- Inho Jo
- Department of Biomedical Sciences, National Institute of Health, 5 Nokbun-dong, Eunpyung-gu, 122-701, Seoul, Republic of Korea
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Abstract
The three major components of dyslipidemia associated with the metabolic syndrome are increased fasting and postprandial triglyceride-rich lipoproteins (TRLs), decreased high-density lipoprotein (HDL), and increased small, dense low-density lipoprotein (LDL) particles. Insulin resistance and compensatory hyperinsulinemia lead to overproduction of very low-density lipoprotein particles. A relative deficiency of lipoprotein lipase, an insulin-sensitive enzyme, is partly responsible for the decreased clearance of fasting and postprandial TRLs, and the decreased production of HDL particles. The resulting increased concentration of cholesteryl ester-rich fasting and postprandial TRLs is the central lipoprotein abnormality of the metabolic syndrome. The increase of small, dense LDL particles, and decrease of large, buoyant HDL particles are consequential events. All these lipoprotein defects contribute largely to the increased cardiovascular disease risk in individuals with insulin resistance. Peroxisome proliferator-activated receptor (PPAR)a, PPARg, and PPARd agonists seem to improve dyslipidemia of the metabolic syndrome by regulating the expression of important genes involved in the deranged lipoprotein metabolism associated with insulin resistance.
Collapse
Affiliation(s)
- Giacomo Ruotolo
- Penn Medical Laboratory, MedStar Research Institute, 108 Irving Street NW, Washington, DC 20010, USA.
| | | |
Collapse
|
46
|
Ginsberg HN, Goldberg IJ. The Pancreas and Lipoprotein Metabolism. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
47
|
Laithwaite JE, Benn SJ, Marshall WS, FitzGerald DJ, LaMarre J. Divergent Pseudomonas exotoxin A sensitivity in normal and transformed liver cells is correlated with low-density lipoprotein receptor-related protein expression. Toxicon 2001; 39:1283-90. [PMID: 11384715 DOI: 10.1016/s0041-0101(00)00260-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pseudomonas exotoxin A (PEA) is an extracellular virulence factor produced by the opportunistic human pathogen Pseudomonas aerguinosa. PEA intoxification begins when PEA binds to the low-density lipoprotein receptor-related protein (LRP). The liver is the primary target of systemic PEA, due largely to the high levels of functional LRP expressed by liver cells. Using a 3H-leucine incorporation assay to measure inhibition of protein synthesis we have demonstrated that normal (BNL CL.2) and transformed (BNL 1ME A7R.1) liver cells exhibit divergent PEA sensitivity; with BNL 1ME A7R.1 cells demonstrating greater PEA sensitivity than their non-transformed counterparts. The receptor-associated protein, a LRP antagonist, decreased PEA toxicity in BNL 1ME A7R.1 cells, confirming the importance of the LRP in PEA intoxification in this cell type. Increased PEA sensitivity in BNL 1ME A7R.1 cells was associated with increased functional cell surface LRP expression, as measured by alpha2-macroglobulin binding and internalization studies, and increased LRP mRNA levels, as determined by Northern blot analysis. Interestingly, BNL CL.2 cells were more sensitive than BNL 1ME A7R.1 cells to conjugate and mutant PEA toxins that do not utilize the LRP for cellular entry. These data demonstrate that increased LRP expression is an important mechanism by which PEA sensitivity is increased in BNL 1ME A7R.1 transformed liver cells.
Collapse
Affiliation(s)
- J E Laithwaite
- Department of Biomedical Sciences, University of Guelph, Ontario, N1G 2W1, Guelph, Canada
| | | | | | | | | |
Collapse
|
48
|
Ko KW, Avramoglu RK, McLeod RS, Vukmirica J, Yao Z. The insulin-stimulated cell surface presentation of low density lipoprotein receptor-related protein in 3T3-L1 adipocytes is sensitive to phosphatidylinositide 3-kinase inhibition. Biochemistry 2001; 40:752-9. [PMID: 11170392 DOI: 10.1021/bi001797+] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The regulation of low density lipoprotein receptor-related protein (LRP) activity by insulin was studied using 3T3-L1 adipocytes. The LRP mRNA and protein expression were independent of differentiation state of the cells and of insulin treatment. In differentiated cells, insulin treatment acutely stimulated the cell surface presentation of LRP (approximately 2-fold) as evidenced by methylamine-activated alpha(2)-macroglobulin binding and by biotinylation of cell surface LRP. The increased cell surface presentation was accompanied by a 39% decrease in LRP level in the low density microsomes. The magnitude of insulin-stimulated cell surface presentation of LRP was similar to that of transferrin receptor but was much less than that of GLUT4. Both the increases in LRP and GLUT4 cell surface presentation upon insulin treatment were abolished by inhibition of phosphatidylinositide 3-kinase. The increased cell surface presentation of LRP was associated with proportionally increased endocytic activity, and the internalization rate constant (K(e)) was not decreased by insulin treatment. Thus, insulin treatment most likely stimulates recycling of LRP from an endosomal pool to the plasma membrane, which is regulated in a phosphatidylinositide 3-kinase-dependent manner in 3T3-L1 adipocytes.
Collapse
Affiliation(s)
- K W Ko
- Lipoprotein and Atherosclerosis Group, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario, Canada
| | | | | | | | | |
Collapse
|
49
|
Activation of factor IX zymogen results in exposure of a binding site for low-density lipoprotein receptor–related protein. Blood 2000. [DOI: 10.1182/blood.v96.10.3459.h8003459_3459_3465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interaction between the endocytic receptor low density lipoprotein receptor–related protein (LRP) and either coagulation factor IX or its active derivative factor IXa was studied. Purified factor IX was unable to associate with LRP when analyzed by surface plasmon resonance. By contrast, factor XIa–mediated conversion of factor IX into factor IXa resulted in reversible dose- and calcium-dependent binding to LRP. Active-site blocking of factor IXa did not affect binding to LRP, whereas LRP binding was efficiently inhibited in the presence of heparin or antibodies against factor IX or LRP. The factor IXa–LRP interaction could be described by a 2-site binding model with equilibrium dissociation constants of 27 nmol/L and 69 nmol/L. Consistent with this model, it was observed that factor IXa binds to 2 different recombinant receptor fragments of LRP (denoted cluster II and cluster IV) with equilibrium dissociation constants of 227 nmol/L and 53 nmol/L, respectively. The amount of factor IXa degraded by LRP-deficient cells was 35% lower than by LRP-expressing cells, demonstrating that LRP contributes to the transport of factor IXa to the intracellular degradation pathway. Because ligand binding to LRP is often preceded by binding to proteoglycans, the contribution of proteoglycans to the catabolism of factor IXa was addressed by employing proteoglycan-deficient cells. Degradation of factor IXa by proteoglycan-deficient cells proceeded at a 83% lower rate than wild-type cells. In conclusion, the data presented here indicate that both LRP and proteoglycans have the potential to contribute to the catabolism of factor IXa.
Collapse
|
50
|
Activation of factor IX zymogen results in exposure of a binding site for low-density lipoprotein receptor–related protein. Blood 2000. [DOI: 10.1182/blood.v96.10.3459] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe interaction between the endocytic receptor low density lipoprotein receptor–related protein (LRP) and either coagulation factor IX or its active derivative factor IXa was studied. Purified factor IX was unable to associate with LRP when analyzed by surface plasmon resonance. By contrast, factor XIa–mediated conversion of factor IX into factor IXa resulted in reversible dose- and calcium-dependent binding to LRP. Active-site blocking of factor IXa did not affect binding to LRP, whereas LRP binding was efficiently inhibited in the presence of heparin or antibodies against factor IX or LRP. The factor IXa–LRP interaction could be described by a 2-site binding model with equilibrium dissociation constants of 27 nmol/L and 69 nmol/L. Consistent with this model, it was observed that factor IXa binds to 2 different recombinant receptor fragments of LRP (denoted cluster II and cluster IV) with equilibrium dissociation constants of 227 nmol/L and 53 nmol/L, respectively. The amount of factor IXa degraded by LRP-deficient cells was 35% lower than by LRP-expressing cells, demonstrating that LRP contributes to the transport of factor IXa to the intracellular degradation pathway. Because ligand binding to LRP is often preceded by binding to proteoglycans, the contribution of proteoglycans to the catabolism of factor IXa was addressed by employing proteoglycan-deficient cells. Degradation of factor IXa by proteoglycan-deficient cells proceeded at a 83% lower rate than wild-type cells. In conclusion, the data presented here indicate that both LRP and proteoglycans have the potential to contribute to the catabolism of factor IXa.
Collapse
|