101
|
Julve J, Escolà-Gil JC, Rotllan N, Fiévet C, Vallez E, de la Torre C, Ribas V, Sloan JH, Blanco-Vaca F. Human apolipoprotein A-II determines plasma triglycerides by regulating lipoprotein lipase activity and high-density lipoprotein proteome. Arterioscler Thromb Vasc Biol 2009; 30:232-8. [PMID: 19910634 DOI: 10.1161/atvbaha.109.198226] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Apolipoprotein (apo) A-II is the second most abundant high-density lipoprotein (HDL) apolipoprotein. We assessed the mechanism involved in the altered postprandial triglyceride-rich lipoprotein metabolism of female human apoA-II-transgenic mice (hapoA-II-Tg mice), which results in up to an 11-fold increase in plasma triglyceride concentration. The relationships between apoA-II, HDL composition, and lipoprotein lipase (LPL) activity were also analyzed in a group of normolipidemic women. METHODS AND RESULTS Triglyceride-rich lipoprotein catabolism was decreased in hapoA-II-Tg mice compared to control mice. This suggests that hapoA-II, which was mainly associated with HDL during fasting and postprandially, impairs triglyceride-rich lipoprotein lipolysis. HDL isolated from hapoA-II-Tg mice impaired bovine LPL activity. Two-dimensional gel electrophoresis, mass spectrometry, and immunonephelometry identified a marked deficiency in the HDL content of apoA-I, apoC-III, and apoE in these mice. In normolipidemic women, apoA-II concentration was directly correlated with plasma triglyceride and inversely correlated with the HDL-apoC-II+apoE/apoC-III ratio [corrected]. HDL-mediated induction of LPL activity was inversely correlated with apoA-II and directly correlated with the HDL-apoC-II+apoE/apoC-III ratio [corrected]. Purified hapoA-II displaced apoC-II, apoC-III, and apoE from human HDL2. Human HDL3 was, compared to HDL2, enriched in apoA-II but poorer in apoC-II, apoC-III, and apoE. CONCLUSIONS ApoA-II plays a crucial role in triglyceride catabolism by regulating LPL activity, at least in part, through HDL proteome modulation.
Collapse
Affiliation(s)
- Josep Julve
- Hospital de la Santa Creu i Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
102
|
Andersson B, Hellgren G, Nierop AFM, Hochberg Z, Albertsson-Wikland K. Proteins related to lipoprotein profile were identified using a pharmaco-proteomic approach as markers for growth response to growth hormone (GH) treatment in short prepubertal children. Proteome Sci 2009; 7:40. [PMID: 19883510 PMCID: PMC2777859 DOI: 10.1186/1477-5956-7-40] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 11/02/2009] [Indexed: 11/26/2022] Open
Abstract
Background The broad range in growth observed in response to growth hormone (GH) treatment is mainly caused by individual variations in both GH secretion and GH sensitivity. Individual GH responsiveness can be estimated using evidence-based models that predict the response to GH treatment; however, these models can be improved. High-throughput proteomics techniques can be used to identify proteins that may potentially be used as variables in such models in order to improve their predictive ability. Previously we have reported that proteomic analyses can identify biomarkers that discriminate between short prepubertal children with idiopathic short stature (ISS) who show good or poor growth in response to GH treatment. In this study we used a pharmaco-proteomic approach to identify novel factors that correlate with the growth response to GH treatment in prepubertal children who are short due to GH deficiency or ISS. The study included 128 short prepubertal children receiving GH treatment, of whom 39 were GH-deficient and 89 had ISS. Serum protein expression profiles at study start and after 1 year of GH treatment were analyzed using SELDI-TOF. Cross-validated regression and random permutation analyses were performed to identify significant correlations between protein expression patterns and the 2-year growth response to GH treatment. Results At start of treatment we identified a combination of seven protein peaks that correlated with the 2-year growth response in the GH-deficient group (R2 = 0.73). After 1 year of treatment, a combination of four peaks in the GH-deficient group (R2 = 0.64), eight peaks in the ISS group R2 = 0.47) and eight peaks in the total study group correlated with the 2-year growth response R2 = 0.38). The peaks identified corresponded to apolipoproteins A-I, A-II, C-I, C-III, transthyretin and serum amyloid A 4, which are all part of the high-density lipoprotein. Conclusion Using a proteomic approach we identified biomarkers related to the lipoprotein profile that could be used to predict growth response to GH treatment in prepubertal children who are short as a result of GH-deficiency or who have ISS. These results support our previous findings that apolipoproteins and transthyretin may have a role in GH sensitivity.
Collapse
Affiliation(s)
- Björn Andersson
- Göteborg Pediatric Growth Research Center, Department of Pediatrics, Institute of Clinical Sciences, University of Gothenburg, Sweden.
| | | | | | | | | |
Collapse
|
103
|
Diez D, Wheelock AM, Goto S, Haeggström JZ, Paulsson-Berne G, Hansson GK, Hedin U, Gabrielsen A, Wheelock CE. The use of network analyses for elucidating mechanisms in cardiovascular disease. MOLECULAR BIOSYSTEMS 2009; 6:289-304. [PMID: 20094647 DOI: 10.1039/b912078e] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Systems biology offers the potential to provide new insights into our understanding of the pathogenesis of complex diseases such as atherosclerosis. It seeks to comprehend the system properties of the non-linear interactions of the multiple biomolecular components that characterize a living organism. An important component of this research approach is identifying the biological networks that connect the differing elements of a system and in the process describe the characteristics that define a shift in equilibrium from a healthy to a diseased state. The utility of this method becomes clear when applied to multifactorial diseases with complex etiologies such as inflammatory-related diseases, herein exemplified by cardiovascular disease. In this study, the application of network theory to systems biology is described in detail and an example is provided using data from a clinical biobank database of carotid endarterectomies from the Karolinska University Hospital (Biobank of Karolinska Endarterectomies, BiKE). Data from 47 microarrays were examined using a combination of Bioconductor modules and the Cytoscape resource with several associated plugins to analyze the transcriptomics data and create a combined gene association and correlation network of atherosclerosis. The methodology and workflow are described in detail, with a total of 43 genes found to be differentially expressed on a gender-specific basis, of which 15 were not directly linked to the sex chromosomes. In particular, the APOC1 gene was 2.1-fold down-regulated in plaques in women relative to men and was selected for further analysis based upon a purported role in cardiovascular disease. The resulting network was identified as a scale-free network that contained specific sub-networks related to immune function and lipid biosynthesis. These sub-networks link atherosclerotic-related genes to other genes that may not have previously known roles in disease etiology and only evidence small alterations, which are challenging to find by statistical and comparison-based methods. A number of Gene Ontology (GO), BioCarta and KEGG pathways involved in the atherosclerotic process were identified in the constructed sub-network, with 19 GO pathways related to APOC1 of which 'phospholipid efflux' evidenced the strongest association. The utility and functionality of network analysis and the different Cytoscape plugins employed are discussed. Lastly, the applications of these methods to cardiovascular disease are discussed with focus on the current limitations and future visions of this emerging field.
Collapse
Affiliation(s)
- Diego Diez
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
104
|
Mulya A, Seo J, Brown AL, Gebre AK, Boudyguina E, Shelness GS, Parks JS. Apolipoprotein M expression increases the size of nascent pre beta HDL formed by ATP binding cassette transporter A1. J Lipid Res 2009; 51:514-24. [PMID: 19767535 DOI: 10.1194/jlr.m002162] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Apolipoprotein M (apoM) is a novel apolipoprotein that is reportedly necessary for pre beta HDL formation; however, its detailed function remains unknown. We investigated the biogenesis and properties of apoM and its effects on the initial steps of nascent pre beta HDL assembly by ABCA1 in HEK293 cells. Transiently transfected apoM was localized primarily in the endomembrane compartment. Pulse-chase analyses demonstrated that apoM is inefficiently secreted, relative to human serum albumin, and that approximately 50% remains membrane-associated after extraction with sodium carbonate, pH 11.5. To investigate the role of apoM in nascent pre beta HDL formation, ABCA1-expressing or control cells, transfected with empty vector, apoM, or C-terminal epitope-tagged apoM (apoM-C-FLAG), were incubated with (125)I-apoA-I for 24 h. Conditioned media were harvested and fractionated by fast-protein liquid chromatography (FPLC) to monitor HDL particle size. Pre beta HDL particles were formed effectively in the absence of apoM expression; however, increased apoM expression stimulated the formation of larger-sized nascent pre beta HDLs. Immunoprecipitation with anti-apoA-I antibody followed by apoM Western blot analysis revealed that little secreted apoM was physically associated with pre beta HDL. Our results suggest that apoM is an atypical secretory protein that is not necessary for ABCA1-dependent pre beta HDL formation but does stimulate the formation of larger-sized pre beta HDL. We propose that apoM may function catalytically at an intracellular site to transfer lipid onto pre beta HDL during or after their formation by ABCA1.
Collapse
Affiliation(s)
- Anny Mulya
- Department of Pathology/Section on Lipid Sciences, Wake Forest University Health Sciences, Winston-Salem, NC 27157, USA
| | | | | | | | | | | | | |
Collapse
|
105
|
Maki KC, Dicklin MR, Lawless A, Reeves MS. Omega-3 fatty acids for the treatment of elevated triglycerides. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/clp.09.34] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
106
|
Cho KH. Biomedicinal implications of high-density lipoprotein: its composition, structure, functions, and clinical applications. BMB Rep 2009; 42:393-400. [DOI: 10.5483/bmbrep.2009.42.7.393] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
|
107
|
Tian L, Wu J, Fu M, Xu Y, Jia L. Relationship between apolipoprotein C-III concentrations and high-density lipoprotein subclass distribution. Metabolism 2009; 58:668-74. [PMID: 19375590 DOI: 10.1016/j.metabol.2009.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 01/13/2009] [Indexed: 02/05/2023]
Abstract
High-density lipoprotein (HDL) subclasses have different antiatherogenic potentials and functional properties. This work presents our findings and discussions on their metabolic implications on apolipoprotein (apo) C-III together with other apolipoprotein levels and HDL subclass distribution profile. Apolipoprotein A-I contents of plasma HDL subclasses were quantitated by 2-dimensional gel electrophoresis coupled with immunodetection in 511 subjects. Concentrations of triglycerides and of apo B-100, C-II, and C-III were higher, whereas those of HDL cholesterol were lower, for subjects in the highest tertile of apo C-III levels group, which presented a typical hypertriglyceridemic lipid profile. Subjects in the middle and highest tertile of apo C-III levels groups had increased prebeta(1)-HDL, HDL(3c), HDL(3b) (only in the highest tertile of apo C-III group), and HDL(3a), but decreased HDL(2a) and HDL(2b) contents compared with subjects in the lowest tertile of apo C-III levels group. With the elevation of apo C-III together with apo C-II levels, contents of small-sized prebeta(1)-HDL increased successively and significantly; but those of large-sized HDL(2b) reduced successively and significantly. With a rise in apo C-III and apo A-I levels, those of prebeta(1)-HDL increased significantly. Moreover, subjects with high apo A-I levels showed a substantial increase in HDL(2b); on the contrary, HDL(2b) declined progressively and obviously for subjects in the low apo A-I levels with the elevation of apo C-III levels. Correlation analysis illustrated that apo C-III levels were positively associated with prebeta(1)-HDL, prebeta(2)-HDL, and HDL(3a). The particle size of HDL shifted toward smaller sizes with the increase of plasma apo C-III levels, and the shift was more remarkable when the elevation of apo C-III and apo C-II was simultaneous; and besides, higher apo A-I concentrations could modify the effect of apo C-III on HDL subclass distribution profile. Large-sized HDL(2b) particles decreased greatly for hypertriglyceridemic subjects who were characterized by elevated apo C-III and C-II accompanied with significantly lower apo A-I, which, in turn, blocked the maturation of HDL.
Collapse
Affiliation(s)
- Li Tian
- Laboratory of Endocrinology and Metabolism, West China Hospital, Sichuan University, Chengdu 610041, Sichuan, People's Republic of China
| | | | | | | | | |
Collapse
|
108
|
Can serum apolipoprotein C-I demonstrate metabolic abnormality early in women with polycystic ovary syndrome? Fertil Steril 2009; 94:205-10. [PMID: 19368908 DOI: 10.1016/j.fertnstert.2009.03.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 02/25/2009] [Accepted: 03/02/2009] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To evaluate the role of apolipoprotein C-I (apoC-I) levels and assess relationships between apoC-I and clinical features in women with polycystic ovary syndrome (PCOS). DESIGN Prospective study. SETTING Reproductive Center of Peking University Third Hospital. PATIENT(S) Thirty patients with PCOS with insulin resistance, 30 patients with PCOS without insulin resistance, and 30 control individuals. INTERVENTION(S) Fasting serum samples. MAIN OUTCOME MEASURE(S) Measures of serum apoC-I, androgens, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, apoA1, apoB, heat-shock C-reactive protein, glucose, and homeostasis model assessment of insulin resistance (HOMA-IR). RESULT(S) We found differentially expressed proteins by use of the surface-enhanced laser adsorption/ionization (SELDI) protein chip in the serum of women with PCOS and controls. Of these, apoC-I, was highly up-regulated. ApoC-I is associated with glycometabolism and lipid metabolism, but its role in PCOS has been unknown. The serum levels of apoC-I in the patients with PCOS were statistically significantly elevated compared with those of controls, especially in women with insulin resistance. The lean PCOS women had higher apoC-I levels than controls. In patients with PCOS and without any abnormal serum lipid index, apoC-I levels were still higher than in controls. Analysis showed that apoC-I correlated with body mass index, triglycerides, high-density lipoprotein cholesterol, apoA1, and HOMA-IR. CONCLUSION(S) ApoC-I may have an important role in glucose and lipid metabolism, and may be useful for early demonstration of metabolic abnormality in women with PCOS.
Collapse
|
109
|
Beesley CE, Young EP, Finnegan N, Jackson M, Mills K, Vellodi A, Cleary M, Winchester BG. Discovery of a new biomarker for the mucopolysaccharidoses (MPS), dipeptidyl peptidase IV (DPP-IV; CD26), by SELDI-TOF mass spectrometry. Mol Genet Metab 2009; 96:218-24. [PMID: 19153055 DOI: 10.1016/j.ymgme.2008.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 12/02/2008] [Indexed: 10/21/2022]
Abstract
Surface enhanced laser desorption/ionisation time of flight (SELDI-TOF) mass spectrometry has been used to search for new protein biomarkers in the plasma of patients with mucopolysacharidoses (MPS). Differences in the levels of some plasma proteins, particularly the apolipoprotein ApoCI, were observed between MPS patients and normal controls, using the different chromatographic surfaces (ProteinChips). ApoCI was identified by both its mass and by immunological techniques. In plasma, it exists in two forms, ApoCI and a truncated form which lacks two N-terminal amino acids, ApoCI'. In controls, the ratio of ApoCI':ApoCI observed using the cation-exchange surface (CM10) was approximately 1:2 whereas in most MPS patients it varied from 1:1 to 1:0.8. The ratio of ApoCI':ApoCI in plasma is determined by the activity of dipeptidyl peptidase IV, DPP-IV (also known as the leucocyte antigen CD26), which was found to be elevated up to 3-fold in MPS patients. The DPP-IV activity decreased in MPS I patients undergoing enzyme replacement therapy, indicating that it could be a useful biomarker for monitoring the efficacy of treatment in MPS disease. As DPP-IV has an important regulatory role in metabolism, it is possible that its elevation could cause some of the secondary pathology in MPS, and inhibition of DPP-IV might have a role in MPS therapy.
Collapse
Affiliation(s)
- Clare E Beesley
- Biochemistry Research Group, UCL Institute of Child Health, Guilford Street, London, United Kingdom.
| | | | | | | | | | | | | | | |
Collapse
|
110
|
Apolipoprotein CI levels are associated with atherosclerosis in men with the metabolic syndrome and systemic inflammation. Atherosclerosis 2009; 203:355-7. [DOI: 10.1016/j.atherosclerosis.2008.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 08/01/2008] [Accepted: 08/01/2008] [Indexed: 11/23/2022]
|
111
|
Cho KH. Synthesis of reconstituted high density lipoprotein (rHDL) containing apoA-I and apoC-III: the functional role of apoC-III in rHDL. Mol Cells 2009; 27:291-7. [PMID: 19326075 DOI: 10.1007/s10059-009-0037-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 11/19/2008] [Accepted: 12/16/2008] [Indexed: 11/24/2022] Open
Abstract
Apolipoprotein (apo) C-III is a marker protein of triacylglycerol (TG)-rich lipoproteins and high-density lipoproteins (HDL), and has been proposed as a risk factor of coronary heart disease. To compare the physiologic role of reconstituted HDL (rHDL) with or without apoC-III, we synthesized rHDL with molar ratios of apoA-I:apoC-III of 1:0, 1:0.5, 1:1, and 1:2. Increasing the apoC-III content in rHDL produced smaller rHDL particles with a lower number of apoA-I molecules. Furthermore, increasing the molar ratio of apoC-III in rHDL enhanced the surfactant-like properties and the ability to lyse dimyristoyl phosphatidylcholine. Furthermore, rHDL containing apoC-III was found to be more resistant to particle rearrangement in the presence of low-density lipoprotein (LDL) than rHDL that contained apoA-I alone. In addition, the lecithin:cholesterol acyltransferase (LCAT) activation ability was reduced as the apoC-III content of the rHDL increased; however, the CE transfer ability was not decreased by the increase of apoC-III. Finally, rHDL containing apoC-III aggravated the production of MDA in cell culture media, which led to increased cellular uptake of LDL.Thus, the addition of apoC-III to rHDL induced changes in the structural and functional properties of the rHDL, especially in particle size and rearrangement and LCAT activation. These alterations may lead to beneficial functions of HDL, which is involved in anti-atherogenic properties in the circulation.
Collapse
Affiliation(s)
- Kyung-Hyun Cho
- School of Biotechnology, Aging-associated Vascular Disease Research Center, Yeungnam University, Gyeongsan 712-749, Korea.
| |
Collapse
|
112
|
Sato I, Ishikawa Y, Ishimoto A, Katsura S, Toyokawa A, Hayashi F, Kawano S, Fujioka Y, Yamashita S, Kumagai S. Significance of Measuring Serum Concentrations of Remnant Lipoproteins and Apolipoprotein B-48 in Fasting Period. J Atheroscler Thromb 2009; 16:12-20. [DOI: 10.5551/jat.e596] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
113
|
Takahashi Y, Inoue J, Kagechika H, Sato R. ApoC-III gene expression is sharply increased during adipogenesis and is augmented by retinoid X receptor (RXR) agonists. FEBS Lett 2008; 583:493-7. [PMID: 19121312 DOI: 10.1016/j.febslet.2008.12.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Revised: 12/20/2008] [Accepted: 12/22/2008] [Indexed: 11/26/2022]
Abstract
ApoC-III, a lipoprotein lipase inhibitor and a key regulator of the metabolism of triglyceride-rich lipoproteins, is mainly synthesized in liver and intestine, but little is known about its expression in adipocytes. We here show that apoC-III mRNA levels are dramatically induced during adipocyte differentiation. Among many transcriptional factors involved in adipocyte differentiation, RXRalpha, acting alone and not as a heterodimer partner of other nuclear receptors, solely regulates apoC-III gene expression. These results suggest that apoC-III may play a specific role in lipid storage and mobilization in adipocytes, non-lipoprotein-secreting cells, and indicate the functional role of RXRalpha during adipocyte differentiation.
Collapse
Affiliation(s)
- Yu Takahashi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | | | | | | |
Collapse
|
114
|
Yamamoto T, Hirano T, Mori Y, Tokuno A, Nagashima M, Takada M, Morita R, Lee S, Hayashi T, Adachi M. Significant increase of apolipoprotein B48 levels by a standard test meal in type 2 diabetic patients with nephropathy. J Atheroscler Thromb 2008; 15:199-205. [PMID: 18776703 DOI: 10.5551/jat.e558] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
AIM We investigated postprandial changes of apolipoprotein (apo) B48 in type 2 diabetics at different stages of diabetic nephropathy in order to explore non-traditional lipid abnormalities in diabetic nephropathy. METHODS Twenty-two healthy controls and 56 type 2 diabetics with normoalbuminuria (NA), microalbuminuria (MA), and overt albuminuria (OA) were enrolled. Blood samples were taken at 0, 1, 2, 4, 6 h after the ingestion of Test meal A (460 Kcal, 18 g fat). The maximal increase of triglyceride (TG) was 40% above baseline in controls and 17% above baseline in diabetics. The incremental area under the curve (iAUC) of TG, however, was comparable among controls and diabetics with NA, MA, and OA. The maximal increase of apoB48 was 92% above baseline in controls and 56-88% above baseline in diabetics. Apo B48-iAUC was significantly higher in diabetics than in controls, and diabetics with OA exhibited the highest apoB48-iAUC among the diabetic subgroups. Small dense low-density lipoprotein-cholesterol (LDL-C) was elevated in diabetic nephropathy, and apoB48-iAUC was positively associated with the level of sd-LDL-C. CONCLUSIONS ApoB48 is a sensitive marker for postprandial lipemia, a condition which is significantly increased in diabetic nephropathy and associated with an increase of potent atherogenic sd- LDL particles.
Collapse
Affiliation(s)
- Takeshi Yamamoto
- First Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
115
|
The differential effects of thiazolidindiones on atherogenic dyslipidemia in type 2 diabetes: what is the clinical significance? Expert Opin Pharmacother 2008; 9:2295-303. [PMID: 18710354 DOI: 10.1517/14656566.9.13.2295] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Diabetic dyslipidemia is typically characterized by an increase in plasma triglycerides, a decrease in high-density lipoprotein cholesterol and a concomitant increase in atherogenic small dense low-density lipoproteins. Thiazolidindiones are able to lower the levels of fasting glucose and glycated hemoglobin significantly by improving insulin sensitivity, as well as improving some aspects of diabetic dyslipidemia: total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol tend to increase while triglycerides are generally decreased. OBJECTIVE This paper reviewed the effects of pioglitazone and rosiglitazone on atherogenic diabetic dyslipidemia, in particular on small dense low-density lipoprotein particles. METHODS A literature search (by Medline and Scopus) was performed up to 15 March 2008. The authors also manually reviewed the references of selected articles for any pertinent material. RESULTS Pioglitazone showed an additional beneficial effect on triglycerides, high-density lipoprotein cholesterol and the levels of small dense low-density lipoprotein compared to rosiglitazone. CONCLUSIONS Since recent studies have suggested that these agents may also have a differential effect on long-term cardiovascular end-points despite similar improvements in glycated hemoglobin and insulin sensitivity, the different impact on atherogenic diabetic dyslipidemia may help to explain these findings.
Collapse
|
116
|
Hsieh FY, Tengstrand E, Pekol TM, Guerciolini R, Miwa G. Elucidation of potential bortezomib response markers in mutliple myeloma patients. J Pharm Biomed Anal 2008; 49:115-22. [PMID: 19062221 DOI: 10.1016/j.jpba.2008.09.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 09/26/2008] [Accepted: 09/29/2008] [Indexed: 10/21/2022]
Abstract
Liquid chromatography coupled to mass spectrometry (LC/MS) was used to elucidate early biomarkers of bortezomib response in multiple myeloma patients. The change in serum myeloma M-protein level, maintained for a minimum of 6 weeks, is used as one of the main criteria to evaluate patient clinical response to therapy. The objective of this study was to identify biomarkers using LC/MS in order to predict patient response to bortezomib sooner and more accurately compared to serum M-protein levels. The plasma LC/MS biomolecular/biochemical profiles, comprised of thousands of endogenous small molecules, peptides and proteins, were determined for 10 multiple myeloma patients at predose and 24 h after initial dosing with bortezomib. The comparative analysis of the metabolic profiles of non-responders and partial responders provided an opportunity to investigate mechanisms related to disease progression and identify biomarkers related to drug response. The plasma levels of two potential efficacy response markers were significantly more abundant in the non-responsive patients compared to the responders at 24-h postdose. The potential response biomarkers, apolipoprotein C-I and apolipoprotein C-I', were identified by mass spectral analyses and confirmed by authentic protein standards based on MALDI-TOF MS/MS sequencing of proteolytic peptides.
Collapse
Affiliation(s)
- Frank Y Hsieh
- Nextcea, Inc., 600 West Cummings Park, #6375, Woburn, MA 01801, United States.
| | | | | | | | | |
Collapse
|
117
|
Chan DC, Watts GF, Ng TWK, Yamashita S, Barrett PHR. Effect of weight loss on markers of triglyceride-rich lipoprotein metabolism in the metabolic syndrome. Eur J Clin Invest 2008; 38:743-51. [PMID: 18837799 DOI: 10.1111/j.1365-2362.2008.02019.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Hypertriglyceridaemia, a consistent feature of dyslipidaemia in the metabolic syndrome (MetS), is related to the extent of abdominal fat mass and altered adipocytokine secretion. We determined the effect of weight loss by dietary restriction on markers of triglyceride-rich lipoprotein (TRL) metabolism and plasma adipocytokines. DESIGN Thirty-five men with MetS participated in a 16 week randomized controlled dietary intervention study. Apolipoprotein (apo) C-III, apoB-48, remnant-like particle (RLP)-cholesterol, total adiponectin, high-molecular weight (HMW) adiponectin, and retinol-binding protein-4 (RBP-4) concentrations were measured using immunoassays. RESULTS Compared with weight maintenance (n = 15), weight loss (n = 20) significantly decreased body weight, plasma insulin, triglycerides, total cholesterol, low-density lipoprotein (LDL)-cholesterol and lathosterol (P < 0.05). Weight loss also decreased plasma concentrations of apoC-III (-33%), apoB-48 (-37%), very low-density lipoprotein (VLDL)-apoB (-43%), RLP-cholesterol (-48%), and RBP-4 (-20%), and significantly increased plasma total (+20%) and HMW-adiponectin (+19%) concentrations. In the weight loss group, reduction in plasma apoC-III was associated (P < 0.05) with reduction in plasma apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides. Increase in total adiponectin was associated (P < 0.05) with the reduction in plasma VLDL-apoB and triglycerides. The changes in HMW-adiponectin and RBP-4 were not associated with changes in plasma apoB-48, apoC-III, VLDL-apoB, RLP-cholesterol or triglycerides. In multiple regression analysis including changes in visceral fat, insulin and total adiponectin concentrations, the fall in plasma apoC-III concentration was an independent predictor of the reductions in plasma apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides concentrations. CONCLUSIONS In men with MetS, weight loss decreases the plasma concentrations of apoB-48, VLDL-apoB, RLP-cholesterol and triglycerides. This effect could partly relate to concomitant changes in plasma apoC-III and adiponectin concentrations that accelerate the catabolism of TRLs.
Collapse
Affiliation(s)
- D C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | | | | | | | | |
Collapse
|
118
|
Toh SA, Rader DJ. Dyslipidemia in insulin resistance: clinical challenges and adipocentric therapeutic frontiers. Expert Rev Cardiovasc Ther 2008; 6:1007-22. [PMID: 18666851 DOI: 10.1586/14779072.6.7.1007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The ever-increasing rates of obesity and diabetes worldwide have the potential to further fuel the epidemic of cardiovascular disease that we are experiencing today. To slow this epidemic successfully, insulin resistance and associated lipid abnormalities that frequently accompany it are key clinical targets. Yet, we are still challenged to reach the mandated clinical goals for lipids that would minimize the development and progression of cardiovascular disease. Adoption of a comprehensive approach by clinicians, in line with recent recommendations for stricter treatment goals for the at-risk patient, is essential to achieving cardiovascular risk reduction. The challenge for clinicians is integrating strategies, approaches and treatments that address the multiple metabolic defects in patients with insulin resistance and dyslipidemia. New perspectives can help effectively meet this ongoing challenge. Emerging evidence suggests that adipose tissue is intimately involved in the inter-relationships between insulin resistance and dyslipidemia. The future probably involves therapeutic strategies that directly target adipose tissue to optimally reduce cardiometabolic risk.
Collapse
Affiliation(s)
- Sue-Anne Toh
- Division of Endocrinology, Diabetes and Metabolism, University of Pennsylvania, 1 Maloney Building, 3400 Spruce Street, Philadelphia, PA 19104, USA.
| | | |
Collapse
|
119
|
Abstract
PURPOSE OF REVIEW To review new data concerning HDL metabolism and cardiovascular disease, the concept of HDL 'functionality', and HDL kinetics in the metabolic syndrome. RECENT FINDINGS HDL-apoA-I and apoA-II may be better predictors of cardiovascular disease than HDL-cholesterol. Cholesteryl ester transfer protein inhibition with torcetrapib does not benefit cardiovascular disease; whether this is related to 'congestion' of HDL transport or a specific off-target vasopressor effect remains unclear. Accelerated catabolism of HDL particles in metabolic syndrome could be due to increased hepatic secretion of apoB and apoC-III, hepatic steatosis, and low plasma adiponectin. The role of serum amyloid A and homocysteine is uncertain. In metabolic syndrome, therapies that could favourably alter HDL transport include weight loss, fish oils, higher dose statins, and fibrates; 'balancing feedback' may offset reduced catabolism of HDL, fenofibrate being the only agent hitherto shown to increase apoA-I production. SUMMARY Elevating HDL-apoA-I and apoA-II may be a more important therapeutic objective than increased HDL-cholesterol. Recent studies underscore the potential value of studying HDL functionality, particularly in the metabolic syndrome. Reverse cholesterol transport can only be reliably probed at present by studying the kinetics of HDL particles or apolipoproteins; new methods are needed for investigating cellular and whole body cholesterol turnover. In metabolic syndrome, HDL-raising therapies have differential impact on HDL kinetics, the optimal endpoint being to increase transport and concentration with unchanged or accelerated catabolism.
Collapse
Affiliation(s)
- Gerald F Watts
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
| | | | | |
Collapse
|
120
|
Franssen R, Visser ME, Kuivenhoven JA, Kastelein JJP, Dallinga-Thie GM, Stroes ESG. Role of lipoprotein lipase in triglyceride metabolism: potential therapeutic target. ACTA ACUST UNITED AC 2008. [DOI: 10.2217/17460875.3.4.385] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
121
|
Dayarathna MKDR, Hancock WS, Hincapie M. A two step fractionation approach for plasma proteomics using immunodepletion of abundant proteins and multi-lectin affinity chromatography: Application to the analysis of obesity, diabetes, and hypertension diseases. J Sep Sci 2008; 31:1156-66. [PMID: 18306431 DOI: 10.1002/jssc.200700271] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Plasma is an important biological material for biomarker discovery. However, the wide dynamic range in protein concentration remains a major challenge. In this paper, we introduce the development of a proteomic platform for analysis of plasma samples. The method utilizes a double fractionation approach which combines the MARS immunodepletion column with multi-lectin affinity chromatography, M-LAC, to deplete the most abundant proteins in plasma, the majority of which are glycosylated. To determine the suitability of this methodology, we applied the workflow described in this study to a sample set composed of four groups: a control pool and three different disease pools: obesity, diabetes, and hypertension. We were able to identify changes in the level of several proteins; for example, a protein such as angiotensinogen was found to be present at high levels in patients with obesity plus diabetes and hypertension. On the other hand, apolipoprotein CI was shown to be elevated in all disease groups. A review of the literature supported our observation. The methodology presented in this report was shown to be effective for profiling changes in the plasma proteome of subjects with obesity and its associated complications such as diabetes and hypertension.
Collapse
Affiliation(s)
- M K Disni R Dayarathna
- Barnett Institute and Department of Chemistry and Chemical Biology, Northeastern University, Boston, USA
| | | | | |
Collapse
|
122
|
Chan DC, Watts GF, Ooi EMM, Ji J, Johnson AG, Barrett PHR. Atorvastatin and fenofibrate have comparable effects on VLDL-apolipoprotein C-III kinetics in men with the metabolic syndrome. Arterioscler Thromb Vasc Biol 2008; 28:1831-7. [PMID: 18566295 DOI: 10.1161/atvbaha.108.170530] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The metabolic syndrome (MetS) is characterized by insulin resistance and dyslipidemia that may accelerate atherosclerosis. Disturbed apolipoprotein (apo) C-III metabolism may account for dyslipidemia in these subjects. Atorvastatin and fenofibrate decrease plasma apoC-III, but the underlying mechanisms are not fully understood. METHODS AND RESULTS The effects of atorvastatin (40 mg/d) and fenofibrate (200 mg/d) on the kinetics of very-low density lipoprotein (VLDL)-apoC-III were investigated in a crossover trial of 11 MetS men. VLDL-apoC-III kinetics were studied, after intravenous d(3)-leucine administration using gas chromatography-mass spectrometry and compartmental modeling. Compared with placebo, both atorvastatin and fenofibrate significantly decreased (P<0.001) plasma concentrations of triglyceride, apoB, apoB-48, and total apoC-III. Atorvastatin, not fenofibrate, significantly decreased plasma apoA-V concentrations (P<0.05). Both agents significantly increased the fractional catabolic rate (+32% and +30%, respectively) and reduced the production rate of VLDL-apoC-III (-20% and -24%, respectively), accounting for a significant reduction in VLDL-apoC-III concentrations (-41% and -39%, respectively). Total plasma apoC-III production rates were not significantly altered by the 2 agents. Neither treatment altered insulin resistance and body weight. CONCLUSIONS Both atorvastatin and fenofibrate have dual regulatory effects on VLDL-apoC-III kinetics in MetS; reduced production and increased fractional catabolism of VLDL-apoC-III may explain the triglyceride-lowering effect of these agents.
Collapse
Affiliation(s)
- Dick C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
| | | | | | | | | | | |
Collapse
|
123
|
Pavlic M, Valéro R, Duez H, Xiao C, Szeto L, Patterson BW, Lewis GF. Triglyceride-rich lipoprotein-associated apolipoprotein C-III production is stimulated by plasma free fatty acids in humans. Arterioscler Thromb Vasc Biol 2008; 28:1660-5. [PMID: 18556566 DOI: 10.1161/atvbaha.108.169383] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Insulin resistant states are associated with increased fatty acid flux to liver and intestine, which stimulates the production of triglyceride-rich lipoproteins (TRL). ApoC-III production and plasma and TRL concentrations are increased in insulin resistance and may contribute to the hypertriglyceridemia of these conditions. The mechanism underlying that increase is not known, but because apoC-III and VLDL production are closely linked we hypothesized that FFAs may stimulate TRL apoC-III production. METHODS AND RESULTS We used Intralipid/heparin (IH) to raise plasma FFA in 12 healthy men in the fed state, and stable isotopes to examine apoC-III metabolism. TRL apoC-III concentration was significantly higher in the IH study, and this increase was associated with higher production (PR) and fractional catabolic rate (FCR). The increase in production was greater than in FCR (90% versus 30%, respectively), accounting for the elevated concentration. Glycerol infusion had no effect on apoC-III concentration, PR, or FCR compared to saline, indicating that the effect was not attributable to glycerol released from intralipid. CONCLUSIONS These findings confirm that TRL apoC-III production is stimulated by an acute elevation of plasma FFAs, suggesting a novel regulatory pathway that may play a role in the overproduction of TRL apoC-III in insulin resistant states.
Collapse
|
124
|
Vislocky LM, Pikosky MA, Rubin KH, Vega-López S, Gaine PC, Martin WF, Zern TL, Lofgren IE, Fernandez ML, Rodriguez NR. Habitual consumption of eggs does not alter the beneficial effects of endurance training on plasma lipids and lipoprotein metabolism in untrained men and women. J Nutr Biochem 2008; 20:26-34. [PMID: 18495465 DOI: 10.1016/j.jnutbio.2007.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 11/20/2007] [Accepted: 11/26/2007] [Indexed: 11/17/2022]
Abstract
Changes in plasma lipid and apolipoprotein profiles were evaluated in 12 healthy, unfit subjects (VO(2peak) 39.1+/-2.8 ml.kg(-1).min(-1); 5 women, 7 men) at baseline and following endurance exercise training. The exercise protocol consisted of a 6-week endurance exercise training program (4-5 days week(-1); 60 min.session(-1); > or =65% HR(max)). Subjects were randomly assigned to consume an egg- (n=6; 12 eggs.week(-1)) or no-egg (n=6; 0 eggs.week(-1))-based, eucaloric, standardized diet for 8 weeks. Both diets were macronutrient balanced [60% carbohydrate, 30% fat, 10% protein (0.8 g.kg(-1).day(-1))] and individually designed for weight maintenance. Plasma lipids were measured twice within the same week at baseline and following exercise training. At baseline, subjects were normolipidemic with values of 163.9+/-41.8, 84.8+/-36.7, 60.6+/-15.4 and 93.1+/-52 mg dl(-1) for total cholesterol, LDL cholesterol and HDL cholesterol and triglyceride concentrations, respectively. A two-way ANOVA was used to analyze diet and exercise effects and interactions. In both groups, endurance exercise training resulted in a significant 10% increase in HDL-C (P<.05), a 19% decrease in Apo B concentrations (P<.05) and reductions in plasma CETP activity (P<.05). Plasma LDL-C decreased by 21% (P=.06). No main effects of diet or interactions with plasma lipids or Apo B concentrations were observed. These data demonstrate that endurance training improved the plasma lipid profiles of previously unfit, normolipidemic subjects independent of dietary cholesterol intake from eggs.
Collapse
Affiliation(s)
- Lisa M Vislocky
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
125
|
|
126
|
Molina S, Missé D, Roche S, Badiou S, Cristol JP, Bonfils C, Dierick JF, Veas F, Levayer T, Bonnefont-Rousselot D, Maurel P, Coste J, Fournier-Wirth C. Identification of apolipoprotein C-III as a potential plasmatic biomarker associated with the resolution of hepatitis C virus infection. Proteomics Clin Appl 2008; 2:751-61. [DOI: 10.1002/prca.200800020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
127
|
Chan DC, Chen MM, Ooi EMM, Watts GF. An ABC of apolipoprotein C-III: a clinically useful new cardiovascular risk factor? Int J Clin Pract 2008; 62:799-809. [PMID: 18201179 DOI: 10.1111/j.1742-1241.2007.01678.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Hypertriglyceridaemia, commonly found in subjects with obesity and type 2 diabetes mellitus, is associated with increased risk of coronary heart disease (CHD). Apolipoprotein C-III (apoC-III) plays an important role in regulating the metabolism of triglyceride-rich lipoproteins (TRLs) and may provide a new approach to assessing hypertriglyceridaemia. AIMS We review the role of apoC-III in regulating TRL metabolism and address the potential importance of apoC-III in clinical practice. DISCUSSION Hypertriglyceridaemia is chiefly a consequence of alterations in the kinetics of TRLs, including overproduction and delayed clearance of very-low density lipoprotein (VLDL). ApoC-III is an inhibitor of lipoprotein lipase and of TRLs remnant uptake by hepatic lipoprotein receptors. Elevated apoC-III, usually resulting from hepatic overproduction of VLDL apoC-III, may cause accumulation of plasma TRLs leading to hypertriglyceridaemia. The results from recent observational studies demonstrate that apoC-III is a strong predictor of risk for CHD, but this chiefly relates to apoC-III in apoB-containing lipoproteins. Lifestyle and pharmacological intervention can correct hypertriglyceridaemia by a mechanism of action that regulates apoC-III transport. CONCLUSIONS Targeting apoC-III metabolism may therefore be an important, new therapeutic approach to managing dyslipidaemia and CHD risk in obesity, insulin resistance and type 2 diabetes mellitus. However, further work is required to establish the practical aspects of measuring apoC-III in routine laboratory service and the precise therapeutic targets for serum total apoC-III and/or apoC-III in apoB-containing lipoproteins. While showing much promise as a potentially useful cardiovascular risk factor, apoC-III is not yet ready for prime time use in clinical practice.
Collapse
Affiliation(s)
- D C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, WA, Australia
| | | | | | | |
Collapse
|
128
|
Guha M, Gantz DL, Gursky O. Effects of acyl chain length, unsaturation, and pH on thermal stability of model discoidal HDLs. J Lipid Res 2008; 49:1752-61. [PMID: 18456639 DOI: 10.1194/jlr.m800106-jlr200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HDLs prevent atherosclerosis by removing excess cell cholesterol. Lipid composition affects HDL functions in cholesterol removal, yet its effects on the disk stability remain unclear. We hypothesize that reduced length or increased cis-unsaturation of phosphatidylcholine acyl chains destabilize discoidal HDL and promote protein dissociation and lipoprotein fusion. To test this hypothesis, we determined thermal stability of binary complexes reconstituted from apoC-I and diacyl PCs containing 12-18 carbons with 0-2 cis-double bonds. Kinetic analysis using circular dichroism shows that, for fully saturated PCs, chain length increase by two carbons stabilizes lipoprotein by deltaDeltaG* (37 degrees C) congruent with 1.4 kcal/mol, suggesting that hydrophobic interactions dominate the disk stability; distinct effects of pH and salt indicate contribution of electrostatic interactions. Similarly, apoA-I-containing disks show increased stability with increasing chain length. Acyl chain unsaturation reduces disk stability. In summary, stability of discoidal HDL correlates directly with fatty acyl chain length and saturation: the longer and more fully saturated are the chains, the more extensive are the stabilizing lipid-protein and lipid-lipid interactions and the higher is the free energy barrier for protein dissociation and lipoprotein fusion. This sheds new light on the existing data of cholesterol efflux to discoidal HDL and suggests that moderate lipoprotein destabilization facilitates cholesterol insertion.
Collapse
Affiliation(s)
- Madhumita Guha
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | | | | |
Collapse
|
129
|
Plasma apolipoprotein CI correlates with increased survival in patients with severe sepsis. Intensive Care Med 2008; 34:907-11. [DOI: 10.1007/s00134-008-1006-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 12/22/2007] [Indexed: 10/22/2022]
|
130
|
The function, composition, and particle size of high-density lipoprotein were severely impaired in an oliguric phase of hemorrhagic fever with renal syndrome patients. Clin Biochem 2008; 41:56-64. [DOI: 10.1016/j.clinbiochem.2007.10.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Revised: 09/12/2007] [Accepted: 10/04/2007] [Indexed: 11/21/2022]
|
131
|
Yamada Y, Matsuo H, Warita S, Watanabe S, Kato K, Oguri M, Yokoi K, Metoki N, Yoshida H, Satoh K, Ichihara S, Aoyagi Y, Yasunaga A, Park H, Tanaka M, Nozawa Y. Prediction of genetic risk for dyslipidemia. Genomics 2007; 90:551-8. [DOI: 10.1016/j.ygeno.2007.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Revised: 08/01/2007] [Accepted: 08/01/2007] [Indexed: 10/22/2022]
|
132
|
Gonzales AM, Orlando RA. Role of adipocyte-derived lipoprotein lipase in adipocyte hypertrophy. Nutr Metab (Lond) 2007; 4:22. [PMID: 17971230 PMCID: PMC2174487 DOI: 10.1186/1743-7075-4-22] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Accepted: 10/30/2007] [Indexed: 12/14/2022] Open
Abstract
Background A major portion of available fatty acids for adipocyte uptake is derived from lipoprotein lipase (LPL)-mediated hydrolysis of circulating lipoprotein particles. In vivo studies aimed at identifying the precise role of adipocyte-derived LPL in fat storage function of adipose tissue have been unable to provide conclusive evidence due to compensatory mechanisms that activate endogenous fatty acid synthesis. To address this gap in knowledge, we have measured the effect of reducing adipocyte LPL expression on intracellular lipid accumulation using a well-established cultured model of adipocyte differentiation. Methods siRNA specific for mouse LPL was transfected into 3T3-L1 adipocytes. Expression of LPL was measured by quantitative real-time PCR and cell surface-associated LPL enzymatic activity was measured by colorimetric detection following substrate (p-nitrophenyl butyrate) hydrolysis. Apolipoprotein CII and CIII expression ratios were also measured by qRT-PCR. Intracellular lipid accumulation was quantified by Nile Red staining. Results During differentiation of 3T3-L1 pre-adipocytes, LPL mRNA expression increases 6-fold resulting in a 2-fold increase in cell surface-associated LPL enzymatic activity. Parallel to this increase in LPL expression, we found that intracellular lipids increased ~10-fold demonstrating a direct correlation between adipocyte-derived LPL expression and lipid storage. We next reduced LPL expression in adipocytes using siRNA transfections to directly quantify the contributions of adipocyte-derived LPL to lipid storage, This treatment reduced LPL mRNA expression and cell surface-associated LPL enzymatic activity to ~50% of non-treated controls while intracellular lipid levels were reduced by 80%. Exogenous addition of purified LPL (to restore extracellular lipolytic activity) or palmitate (as a source of free fatty acids) to siRNA-treated cells restored intracellular lipid levels to those measured for non-treated controls. We also found that adipocytes express apolipoprotein CII and CIII and, in addition, the apoCII/apoCIII ratio remains largely unchanged in cells with reduced LPL expression. Conclusion We provide evidence that adipocyte-derived LPL is required for efficient fatty acid uptake and storage, and that adipocytes express their own source of apoCII and apoCIII for regulating extracellular LPL activity. These findings demonstrate that adipocytes are capable of producing the necessary enzymatic components and co-factors for efficient lipid storage independent of vascular sources.
Collapse
Affiliation(s)
- Amanda M Gonzales
- Department of Biochemistry and Molecular Biology, University of New Mexico, School of Medicine, MSC08 4670, 1 University of New Mexico, Albuquerque, New Mexico, 87131, USA.
| | | |
Collapse
|
133
|
Wang J, Liu N, Liu Z, Li Y, Song C, Yuan H, Li YY, Zhao X, Lu H. The orphan nuclear receptor Rev-erbbeta recruits Tip60 and HDAC1 to regulate apolipoprotein CIII promoter. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1783:224-36. [PMID: 17996965 DOI: 10.1016/j.bbamcr.2007.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 08/21/2007] [Accepted: 09/20/2007] [Indexed: 11/19/2022]
Abstract
Nuclear hormone receptors function as ligand activated transcription factors. Ligand binding and modification such as acetylation have been reported to regulate nuclear hormone receptors. The orphan receptors, Rev-erbalpha and Rev-erbbeta, are members of the nuclear receptor superfamily and act as transcriptional repressors. In this study, the role of recruitment of co-factors by Rev-erbbeta and acetylation of Rev-erbbeta in modulating apolipoprotein CIII (apoCIII) transcription were investigated. Rev-erbbeta was found to transcriptionally repress apoCIII after binding to the apoCIII promoter. Tip60, a histone acetyl-transferase (HAT), was a novel binding partner for Rev-erbbeta and recruited to the apoCIII promoter by Rev-erbbeta. Tip60 was able to acetylate Rev-erbbeta and relieve the apoCIII repression mediated by Rev-erbbeta. This de-repression effect depended on acetylation of Rev-erbbeta at its RXKK motif by Tip60. In addition, histone deacetylase 1 (HDAC1) interacted with Rev-erbbeta and was recruited to the apoCIII promoter by Rev-erbbeta to antagonize Tip60's activity. Taken together, we have provided evidence that Rev-erbbeta modulates the apoCIII gene expression by recruiting different transcription co-activator or co-repressor.
Collapse
Affiliation(s)
- Jiadong Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Fudan University, Shanghai 200433, China
| | | | | | | | | | | | | | | | | |
Collapse
|
134
|
Deeg MA, Buse JB, Goldberg RB, Kendall DM, Zagar AJ, Jacober SJ, Khan MA, Perez AT, Tan MH. Pioglitazone and rosiglitazone have different effects on serum lipoprotein particle concentrations and sizes in patients with type 2 diabetes and dyslipidemia. Diabetes Care 2007; 30:2458-64. [PMID: 17595355 DOI: 10.2337/dc06-1903] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Associated with insulin resistance in type 2 diabetes are increased serum triglycerides, decreased HDL cholesterol, and a predominance of large VLDL, small LDL, and small HDL particles. The comparative effects of thiazolidinedione insulin sensitizers on serum lipoprotein particle concentrations and sizes in type 2 diabetes are not known. We studied the effects of pioglitazone (PIO) and rosiglitazone (ROSI) treatments on serum lipoprotein particle concentrations and sizes in type 2 diabetic patients with dyslipidemia. RESEARCH DESIGN AND METHODS This is a prospective, randomized, double-blind, multicenter, parallel-group study. After a 4-week placebo washout period, patients randomized to PIO (n = 369) were treated with 30 mg q.d. for 12 weeks followed by 45 mg q.d. for another 12 weeks, while patients randomized to ROSI (n = 366) were treated with 4 mg q.d. followed by 4 mg b.i.d. for the same intervals. Lipoprotein subclass particle concentrations and sizes were determined by proton nuclear magnetic resonance spectroscopy at baseline and end point (PIO [n = 333] and ROSI [n = 325] patients). RESULTS PIO treatment increased total VLDL particle concentration less than ROSI treatment and decreased VLDL particle size more than ROSI. PIO treatment reduced total LDL particle concentration, whereas ROSI treatment increased it. Both treatments increased LDL particle size, with PIO treatment having a greater effect. Whereas PIO treatment increased total HDL particle concentration and size, ROSI treatment decreased them; both increased HDL cholesterol levels. CONCLUSIONS PIO and ROSI treatments have different effects on serum lipoprotein subclass particle concentrations and sizes in patients with type 2 diabetes and dyslipidemia.
Collapse
Affiliation(s)
- Mark A Deeg
- Department of Endocrinology and Metabolism, Veterans Affairs Hospital and Indiana University, Indianapolis, Indiana, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
135
|
Dautin G, Soltani Z, Ducloux D, Gautier T, Pais de Barros JP, Gambert P, Lagrost L, Masson D. Hemodialysis reduces plasma apolipoprotein C-I concentration making VLDL a better substrate for lipoprotein lipase. Kidney Int 2007; 72:871-8. [PMID: 17667986 DOI: 10.1038/sj.ki.5002449] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Apolipoprotein Cs (apoC-1, apoC-II, and apoC-III) are lipoprotein components that have regulatory effects on enzymes involved in lipoprotein metabolism. Owing to their low molecular weights, apoCs can adsorb onto and/or pass through dialysis membranes. Our study determines the consequence of hemodialysis (HD) on plasma concentrations of apoCs and on the activities of enzymes modulated by apoCs. Plasma samples were collected from 28 patients with chronic renal failure before and after HD. Plasma apoC-II levels were unchanged, whereas apoC-III levels were slightly decreased in post-dialysis plasmas. The apoC-I content was markedly reduced during HD. This was due to a significant decrease in the apoC-I content of very low-density lipoprotein (VLDL), whereas the apoC-I content of high-density lipoprotein (HDL) was unchanged. Although HDL bound apoC-I is thought to inhibit cholesterol ester transfer protein, no change in the ability of pre- and post-dialysis VLDL to interact with the transfer protein were observed. Complementary experiments confirmed that VLDL-bound apoC-I has no transfer protein inhibitory potential. In contrast, an increase in the ability of post-dialysis apoC-I-poor VLDL to act as substrate for lipoprotein lipase (LPL) was found compared to pre-dialysis VLDL. Our study shows that apoC-I losses during HD might be beneficial by improving the ability of VLDL to be a substrate for LPL thus improving plasma triglyceride metabolism.
Collapse
Affiliation(s)
- G Dautin
- 1INSERM U866, Faculté de Médecine, Dijon, France
| | | | | | | | | | | | | | | |
Collapse
|
136
|
Wang J, Li Y, Zhang M, Liu Z, Wu C, Yuan H, Li YY, Zhao X, Lu H. A zinc finger HIT domain-containing protein, ZNHIT-1, interacts with orphan nuclear hormone receptor Rev-erbbeta and removes Rev-erbbeta-induced inhibition of apoCIII transcription. FEBS J 2007; 274:5370-81. [PMID: 17892483 DOI: 10.1111/j.1742-4658.2007.06062.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The orphan receptors, Rev-erbalpha and Rev-erbbeta, are members of the nuclear receptor superfamily and specifically repress apolipoprotein CIII (apoCIII) gene expression in rats and humans. Moreover, Rev-erbalpha null mutant mice have elevated very low density lipoprotein triacylglycerol and apoCIII levels. However, ligands for Rev-erb are unknown and the regulatory mechanism of Rev-erb is poorly understood. Conceivably, cofactors for Rev-erb may play an important role in the regulation of lipid metabolism. In this study, a zinc finger HIT domain-containing protein, ZNHIT-1, interacted with Rev-erbbeta. ZNHIT-1 was found to be a conserved protein in eukaryotes and was highly abundant in human liver. Furthermore, ZNHIT-1 was identified as a nuclear protein. Serial truncated fragments and substitution mutations established a putative nuclear localization signal at amino acids 38-47 of ZNHIT-1. A putative ligand-binding domain of Rev-erbbeta and the FxxLL motif of ZNHIT-1 were required for their interaction. Finally, ZNHIT-1 was recruited by Rev-erbbeta to the apoCIII promoter and removed the Rev-erbbeta-induced inhibition of apoCIII transcription. These findings demonstrate that ZNHIT-1 functions as a cofactor to regulate the activity of Rev-erbbeta, and may play a role in lipid metabolism.
Collapse
Affiliation(s)
- Jiadong Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | | | | | | | | | | | | | | | | |
Collapse
|
137
|
Tonstad S, Retterstøl K, Ose L, Ohman KP, Lindberg MB, Svensson M. The dual peroxisome proliferator-activated receptor alpha/gamma agonist tesaglitazar further improves the lipid profile in dyslipidemic subjects treated with atorvastatin. Metabolism 2007; 56:1285-92. [PMID: 17697874 DOI: 10.1016/j.metabol.2007.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 05/14/2007] [Indexed: 11/16/2022]
Abstract
Tesaglitazar (GALIDA; AstraZeneca, Wilmington, DE) is a dual peroxisome proliferator-activated receptor alpha/gamma agonist previously in clinical development for the treatment of glucose and lipid abnormalities associated with type 2 diabetes mellitus and insulin resistance. This study compared the efficacy of tesaglitazar with that of pioglitazone as adjunctive therapy to atorvastatin in subjects with abdominal obesity and dyslipidemia. In this open-label, 3-way crossover study, 58 subjects received atorvastatin 10 mg once daily in a 6-week run-in period, followed by tesaglitazar 3 mg, pioglitazone 45 mg, or placebo, as adjunctive therapy to atorvastatin, in a randomized sequence for 6 weeks each. Serum triglycerides and other lipids, apolipoproteins, glucose, and insulin concentrations were compared between treatments. Tesaglitazar adjunctive therapy reduced serum triglycerides significantly more from baseline (-1.07 mmol/L) than pioglitazone (-0.33 mmol/L; P = .007) or placebo (-0.09 mmol/L; P < .0001). Tesaglitazar also resulted in significantly greater improvements in free fatty acids, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio, low-density lipoprotein particle size, apolipoprotein (apo) B, apo C-III, and the apo B/apo A-I ratio compared with pioglitazone or placebo. Tesaglitazar adjunctive therapy also reduced fasting plasma glucose, fasting plasma insulin, and insulin resistance (homeostasis model assessment index) significantly more than pioglitazone or placebo (P < .0001 for all comparisons). Tesaglitazar was generally well tolerated in combination with atorvastatin, but hemoglobin and absolute neutrophil count decreased and serum creatinine increased more with tesaglitazar than with pioglitazone or placebo. These effects, also shown in previous trials, led to the discontinuation of the clinical development of the drug. In conclusion, the addition of tesaglitazar to a background of atorvastatin therapy further improved the dyslipidemia associated with insulin resistance.
Collapse
Affiliation(s)
- Serena Tonstad
- Department of Preventive Cardiology, Ullevål University Hospital, N-0407, Oslo, Norway.
| | | | | | | | | | | |
Collapse
|
138
|
Dreux M, Boson B, Ricard-Blum S, Molle J, Lavillette D, Bartosch B, Pécheur EI, Cosset FL. The exchangeable apolipoprotein ApoC-I promotes membrane fusion of hepatitis C virus. J Biol Chem 2007; 282:32357-69. [PMID: 17761674 DOI: 10.1074/jbc.m705358200] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cell entry of hepatitis C virus (HCV) is strikingly linked to lipoproteins and their receptors. Particularly, high density lipoprotein (HDL) enhances infectivity of HCV by involving the lipid-transfer function of the scavenger receptor BI, a receptor for both HDL and HCV. Here, we demonstrate that apoC-I, an exchangeable apolipoprotein that predominantly resides in HDL, specifically enhances HCVcc and HCVpp infectivity and increases the fusion rates between viral and target membranes via a direct interaction with the HCV surface. We identify the hypervariable region 1, located at the N terminus of the HCV E2 glycoprotein, as an essential viral component that modulates apoC-I-mediated enhancement of HCV fusion properties. The affinity of apoC-I for the HCV membrane may predispose it for fusion with a target membrane via alterations of its outer phospholipid layer. Conversely, we found that excess apoC-I provided as lipoprotein-free protein induces the disruption of the HCV membrane and subsequent loss of infectivity. Furthermore, our data indicate that HDL neither interacts nor spontaneously exchanges apoC-I with HCV virions. Because apoC-I is not present in serum as a lipoprotein-free form, our results suggest that HDL-embedded apoC-I could be released from the lipoprotein particle through a fine-tuned mechanism regulated via a triple interplay between hypervariable region 1, HDL, and scavenger receptor BI, resulting in optimal apoC-I recruitment on the viral membrane. These results provide the first description of a host serum factor helping the fusion process of an enveloped virus.
Collapse
Affiliation(s)
- Marlène Dreux
- Université de Lyon, (UCB-Lyon1), IFR128, INSERM, U758, and Ecole Normale Supérieure de Lyon, Lyon, F-69007, France
| | | | | | | | | | | | | | | |
Collapse
|
139
|
Godsland IF, Johnston DG, Chaturvedi N. Mechanisms of disease: lessons from ethnicity in the role of triglyceride metabolism in ischemic heart disease. ACTA ACUST UNITED AC 2007; 3:530-8. [PMID: 17581622 DOI: 10.1038/ncpendmet0530] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Accepted: 12/29/2006] [Indexed: 11/09/2022]
Abstract
Mean risk factor levels in various ethnic groups illustrate the potential importance of triglyceride metabolism in the risk for ischemic heart disease (IHD). Serum triglyceride concentrations are a surrogate for a range of potentially atherogenic disturbances in lipoprotein species, including increased concentrations of remnants of VLDL and chylomicron metabolism, increased small, dense LDL concentrations and reduced HDL concentrations. Differences between at-risk groups in lipoprotein profiles reflect alterations in the metabolism of triglycerides that might be greater than differences observed when only circulating triglyceride concentrations are measured. This atherogenic lipoprotein profile is typically found in association with increased visceral fat, insulin resistance and type 2 diabetes and might be a characteristic of Asian Indian ethnicity. By contrast, despite being relatively insulin resistant, Afro-Caribbean men in the UK have a low risk of IHD and lack the adverse lipoprotein profile. This could result from secretion of relatively large proportions of their VLDL as small, triglyceride-poor particles, levels of which are not augmented in response to loss of insulin action. These considerations re-endorse the potential importance of triglyceride metabolism in IHD and present opportunities for identifying useful areas in which drug targets for reducing IHD risk can be sought.
Collapse
Affiliation(s)
- Ian F Godsland
- Endocrinology and Metabolic Medicine, Imperial College London, St Mary's Hospital, London, UK.
| | | | | |
Collapse
|
140
|
Zhao S, Qiao J, Li M, Zhang X, Yu J, Li R. Discovery of distinct protein profiles for polycystic ovary syndrome with and without insulin resistance by surface-enhanced laser adsorption/ionization time of flight mass spectrometry. Fertil Steril 2007; 88:145-51. [PMID: 17562338 DOI: 10.1016/j.fertnstert.2006.11.207] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 11/16/2006] [Accepted: 11/20/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To screen the serum protein expression profiles in patients having polycystic ovary syndrome (PCOS) with or without insulin resistance (IR) and search for discriminatory proteins. DESIGN Cross-sectional study. SETTING Reproductive Center of Peking University Third Hospital. PATIENT(S) Thirty patients with PCOS with IR, 30 patients with PCOS without IR, and 30 control individuals. INTERVENTION(S) Fasting serum samples. MAIN OUTCOME MEASURE(S) Serum protein peak spectrum. RESULT(S) There were 27 differential protein peaks between patients with PCOS and IR and controls, 17 between patients with PCOS without IR and controls, and 19 between patients with PCOS and IR and patients without IR. Marker proteins from differentially expressed proteins were screened out with use of a support vector machine and were used to establish three diagnostic models for PCOS IR, PCOS non-IR, and IR, respectively. CONCLUSION(S) There were statistically significantly different serum proteomic patterns in different types of PCOS. With use of ProteinChip combined with the support vector machine, computer diagnostic models for PCOS with and without IR were set up quickly and efficiently. These discriminatory proteins may help us understand the proteomic changes in serum and find out potential biomarkers of PCOS and IR.
Collapse
Affiliation(s)
- Shuyun Zhao
- Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing, People's Republic of China
| | | | | | | | | | | |
Collapse
|
141
|
Benjwal S, Jayaraman S, Gursky O. Role of secondary structure in protein-phospholipid surface interactions: reconstitution and denaturation of apolipoprotein C-I:DMPC complexes. Biochemistry 2007; 46:4184-94. [PMID: 17341095 PMCID: PMC2584444 DOI: 10.1021/bi062175c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Binding of protein to a phospholipid surface is commonly mediated by amphipathic alpha-helices. To understand the role of alpha-helical structure in protein-lipid interactions, we used discoidal lipoproteins reconstituted from dimyristoylphosphatidylcholine (DMPC) and human apolipoprotein C-I (apoC-I, 6 kDa) or its mutants containing single Pro substitutions along the sequence and differing in their alpha-helical content in solution (0-48%) and on DMPC (40-75%). Thermal denaturation revealed that lipoprotein stability correlates weakly with the protein helix content: proteins with higher alpha-helical content on DMPC may form more stable complexes. Lipoprotein reconstitution upon cooling from the heat-denatured state and DMPC clearance studies revealed that protein secondary structure in solution and on DMPC correlates strongly with the maximal temperature of lipoprotein reconstitution: more helical proteins can reconstitute lipoproteins at higher temperatures. Interestingly, at Tc = 24 degrees C of the DMPC gel-to-liquid crystal transition, the clearance rate is independent of the protein helical content. Consequently, if the packing defects at the phospholipid surface are readily available (e.g., at the lipid phase boundary), insertion of protein into these defects is independent of the secondary structure in solution. However, if hydrophobic defects are limited, protein binding and insertion are aided by other surface-bound proteins and depend on their helical propensity: the larger the propensity, the faster the binding and the broader its temperature range. This positive cooperativity in binding of alpha-helices to phospholipid surface, which may result from direct and/or lipid-mediated protein-protein interactions, may be important for lipoprotein metabolism and for protein-membrane binding.
Collapse
Affiliation(s)
- Sangeeta Benjwal
- Department of Physiology and Biophysics, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts 02118, USA
| | | | | |
Collapse
|
142
|
Porter CJH, Trevaskis NL, Charman WN. Lipids and lipid-based formulations: optimizing the oral delivery of lipophilic drugs. Nat Rev Drug Discov 2007; 6:231-48. [PMID: 17330072 DOI: 10.1038/nrd2197] [Citation(s) in RCA: 1232] [Impact Index Per Article: 72.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Highly potent, but poorly water-soluble, drug candidates are common outcomes of contemporary drug discovery programmes and present a number of challenges to drug development - most notably, the issue of reduced systemic exposure after oral administration. However, it is increasingly apparent that formulations containing natural and/or synthetic lipids present a viable means for enhancing the oral bioavailability of some poorly water-soluble, highly lipophilic drugs. This Review details the mechanisms by which lipids and lipidic excipients affect the oral absorption of lipophilic drugs and provides a perspective on the possible future applications of lipid-based delivery systems. Particular emphasis has been placed on the capacity of lipids to enhance drug solubilization in the intestinal milieu, recruit intestinal lymphatic drug transport (and thereby reduce first-pass drug metabolism) and alter enterocyte-based drug transport and disposition.
Collapse
Affiliation(s)
- Christopher J H Porter
- Department of Pharmaceutics, Victorian College of Pharmacy, Monash University, Parkville campus, 381 Royal Parade, Parkville, Victoria 3052, Australia.
| | | | | |
Collapse
|
143
|
Petit V, Niot I, Poirier H, Besnard P. Absorption intestinale des acides gras: faits et incertitudes. NUTR CLIN METAB 2007. [DOI: 10.1016/j.nupar.2007.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
144
|
Zheng C, Khoo C, Ikewaki K, Sacks FM. Rapid turnover of apolipoprotein C-III-containing triglyceride-rich lipoproteins contributing to the formation of LDL subfractions. J Lipid Res 2007; 48:1190-203. [PMID: 17314277 DOI: 10.1194/jlr.p600011-jlr200] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The atherogenicity theory for triglyceride-rich lipoproteins (TRLs; VLDL + intermediate density lipoprotein) generally cites the action of apolipoprotein C-III (apoC-III), a component of some TRLs, to retard their metabolism in plasma. We studied the kinetics of multiple TRL and LDL subfractions according to the content of apoC-III and apoE in 11 hypertriglyceridemic and normolipidemic persons. The liver secretes mainly two types of apoB lipoproteins: TRL with apoC-III and LDL without apoC-III. Approximately 45% of TRLs with apoC-III are secreted together with apoE. Contrary to expectation, TRLs with apoC-III but not apoE have fast catabolism, losing some or all of their apoC-III and becoming LDL. In contrast, apoE directs TRL flux toward rapid clearance, limiting LDL formation. Direct clearance of TRL with apoC-III is suppressed among particles also containing apoE. TRLs without apoC-III or apoE are a minor, slow-metabolizing precursor of LDL with little direct removal. Increased VLDL apoC-III levels are correlated with increased VLDL production rather than with slow particle turnover. Finally, hypertriglyceridemic subjects have significantly greater production of apoC-III-containing VLDL and global prolongation in residence time of all particle types. ApoE may be the key determinant of the metabolic fate of atherogenic apoC-III-containing TRLs in plasma, channeling them toward removal from the circulation and reducing the formation of LDLs, both those with apoC-III and the main type without apoC-III.
Collapse
Affiliation(s)
- Chunyu Zheng
- Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA
| | | | | | | |
Collapse
|
145
|
Fiegenbaum M, de Andrade FM, Hutz MH. Association between plasma lipid parameters and APOC3 genotypes in Brazilian subjects: effect of gender, smoking and APOE genotypes. Clin Chim Acta 2007; 380:175-81. [PMID: 17367769 DOI: 10.1016/j.cca.2007.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 02/06/2007] [Accepted: 02/07/2007] [Indexed: 02/06/2023]
Abstract
BACKGROUND APOC3 polymorphisms were associated with lipid parameters and coronary artery disease in several populations but not all. Considering the multifactorial inheritance and environmental factors that underlie the determination of triglyceride (TG) and HDL-C levels, the aims of the present study were to perform association analyses of APOC3 polymorphisms and these lipids in a southern Brazilian population of European descent to investigate possible interactions with other genetic and/or environmental factors. METHODS Six hundred and seventy-three subjects participated in the study. -482C>T, -455T>C and 3238C>G polymorphisms genotyping were carried out by PCR followed by restriction enzyme digestion. RESULTS In female subjects the APOC3-APOE genotype combinations had a significant effect on triglyceride levels (ANOVA, P=0.009). Post hoc analysis showed that the observed differences were between APOC3 S(*)2 carriers and S(*)1S(*)1 homozygotes in individuals with an APOE(*)3/3 genotype (Tukey HSD post hoc test, P=0.027). In APOE(*)3/(*)3 subjects, the raising effect of APOC3 S(*)2 allele on TG concentrations was more pronounced in female smokers (+59.4%) than in nonsmokers (+18.8%, P of S(*)2-smoking interaction=0.009). Among APOE(*)3/(*)3 subjects, male carriers of the less common alleles -482T and -455C had significant lower levels of HDL-C compared to homozygotes -482C/C and -455T/T (P=0.02 and P=0.006, respectively). CONCLUSION APOC3 polymorphisms were associated with lipid variables, but the magnitude of these associations was modulated by additional genetic, biologic and/or environmental factors.
Collapse
Affiliation(s)
- Marilu Fiegenbaum
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | | |
Collapse
|
146
|
Brown WV. High-density lipoprotein and transport of cholesterol and triglyceride in blood. J Clin Lipidol 2007; 1:7-19. [PMID: 21291664 DOI: 10.1016/j.jacl.2007.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2007] [Accepted: 02/06/2007] [Indexed: 01/03/2023]
Abstract
High-density lipoproteins (HDL) contain approximately 25% of the cholesterol and <5% of the triglyceride in the plasma of human blood. However, the dynamic exchange of lipids and lipid-binding proteins is not revealed by simply considering the mass of material at any point in time. HDL are the most complex of lipoprotein species with multiple protein constituents, which facilitate cholesterol secretion from cells, cholesterol esterification in plasma, and transfer of cholesterol to other lipoproteins and to the liver for excretion. They also play a major role in triglyceride transport by providing for activation of lipoprotein lipase, exchange of triglyceride among the lipoproteins, and removal of triglyceride rich remnants of chylomicrons and very-low-density lipoproteins after lipase action. In addition, antioxidative enzymes and phospholipid transfer proteins are important components of HDL. Many of the proteins of HDL are exchangeable with other lipoproteins, including chylomicrons and very-low-density lipoproteins. The constantly changing content of lipids and apolipoproteins in HDL particles generate a series of structures that can be analyzed by using separation techniques that depend on size or charge of the particles. Interaction of these various structures can be very different with cell surfaces depending on the size or apolipoprotein content. A series of different transport proteins preferentially exchange lipids with specific structures among the HDL but interact poorly or not at all with others. The role of these differing forms of HDL and their interactions with cells and other lipoprotein species in plasma is the subject of intense study stimulated by the potential for reducing atherogenesis. The strength of this is only partially indicated by the correlation of higher total levels of the HDL particles with reduced incidence of vascular disease in various clinical trials and epidemiological studies.
Collapse
Affiliation(s)
- William Virgil Brown
- Emory University School of Medicine and the Atlanta Veterans Affairs Medical Center 111, 1670 Clairmont Road, Atlanta, GA 30033, USA
| |
Collapse
|
147
|
Qu S, Su D, Altomonte J, Kamagate A, He J, Perdomo G, Tse T, Jiang Y, Dong HH. PPAR{alpha} mediates the hypolipidemic action of fibrates by antagonizing FoxO1. Am J Physiol Endocrinol Metab 2007; 292:E421-34. [PMID: 16985262 PMCID: PMC2665003 DOI: 10.1152/ajpendo.00157.2006] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-fructose consumption is associated with insulin resistance and diabetic dyslipidemia, but the underlying mechanism is unclear. We show in hamsters that high-fructose feeding stimulated forkhead box O1 (FoxO1) production and promoted its nuclear redistribution in liver, correlating with augmented apolipoprotein C-III (apoC-III) production and impaired triglyceride metabolism. High-fructose feeding upregulated peroxisome proliferator-activated receptor-gamma coactivator-1beta and sterol regulatory element binding protein-1c expression, accounting for increased fat infiltration in liver. High-fructose-fed hamsters developed hypertriglyceridemia, accompanied by hyperinsulinemia and glucose intolerance. These metabolic aberrations were reversible by fenofibrate, a commonly used anti-hypertriglyceridemia agent that is known to bind and activate peroxisome proliferator-activated receptor-alpha (PPARalpha). PPARalpha physically interacted with, but functionally antagonized, FoxO1 in hepatic apoC-III expression. These data underscore the importance of FoxO1 deregulation in the pathogenesis of hypertriglyceridemia in high-fructose-fed hamsters. Counterregulation of hepatic FoxO1 activity by PPARalpha constitutes an important mechanism by which fibrates act to curb apoC-III overproduction and ameliorate hypertriglyceridemia.
Collapse
Affiliation(s)
- Shen Qu
- Rangos Research Center, Children's Hospital of Pittsburgh, Pittsburgh, PA 15213, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
148
|
Göbel T, Vorderwülbecke S, Hauck K, Fey H, Häussinger D, Erhardt A. New multi protein patterns differentiate liver fibrosis stages and hepatocellular carcinoma in chronic hepatitis C serum samples. World J Gastroenterol 2006; 12:7604-12. [PMID: 17171788 PMCID: PMC4088041 DOI: 10.3748/wjg.v12.i47.7604] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To identify a multi serum protein pattern as well as single protein markers using surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF-MS) for detection and differentiation of liver fibrosis (F1-F2), liver cirrhosis (F4) and hepatocellular carcinoma (HCC) in patients with chronic hepatitis C virus (HCV).
METHODS: Serum samples of 39 patients with F1/F2 fibrosis, 44 patients with F4 fibrosis, 34 patients with HCC were applied to CM10 arrays and analyzed using the SELDI-TOF ProteinChip System (PBS-IIc; Ciphergen Biosystems) after anion-exchange fractionation. All patients had chronic hepatitis C and histologically confirmed fibrosis stage/HCC. Data were analyzed for protein patterns by multivariate statistical techniques and artificial neural networks.
RESULTS: A 4 peptide/protein multimarker panel (7486, 12 843, 44 293 and 53 598 Da) correctly identified HCCs with a sensitivity of 100% and specificity of 85% in a two way-comparison of HCV-cirrhosis versus HCV-HCC training samples (AUROC 0.943). Sensitivity and specificity for identification of HCC were 68% and 80% for random test samples. Cirrhotic patients could be discriminated against patients with F1 or F2 fibrosis using a 5 peptide/protein multimarker pattern (2873, 6646, 7775, 10 525 and 67 867 Da) with a specificity of 100% and a sensitivity of 85% in training samples (AUROC 0.976) and a sensitivity and specificity of 80% and 67% for random test samples. Combination of the biomarker classifiers with APRI score and alfa-fetopotein (AFP) improved the diagnostic performance. The 6646 Da marker protein for liver fibrosis was identified as apolipoprotein C-I.
CONCLUSION: SELDI-TOF-MS technology combined with protein pattern analysis seems a valuable approach for the identification of liver cirrhosis and hepatocellular carcinoma in patients with chronic hepatitis C. Most probably a combination of different serum markers will help to identify liver cirrhosis and early-stage hepatocellular carcinomas in the future.
Collapse
Affiliation(s)
- Thomas Göbel
- Klinik für Gastroenterologie, Hepatologie und Infektiologie, Heinrich-Heine-Universität Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | | | | | | | | | | |
Collapse
|
149
|
Hallman DM, Srinivasan SR, Chen W, Boerwinkle E, Berenson GS. Longitudinal analysis of haplotypes and polymorphisms of the APOA5 and APOC3 genes associated with variation in serum triglyceride levels: the Bogalusa Heart Study. Metabolism 2006; 55:1574-81. [PMID: 17142127 DOI: 10.1016/j.metabol.2006.07.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Accepted: 07/24/2006] [Indexed: 11/17/2022]
Abstract
Polymorphisms in the APOC3 and APOA5 genes, from the APOA1/APOC3/APOA4/APOA5 gene cluster on chromosome 11q23, have been associated with interindividual variation in plasma triglycerides. APOA5 polymorphisms implicated include 2 in the promoter region (-1131 T/C and -3 A/G) and 1 in exon 2 (+56 C/G). APOC3 polymorphisms implicated include 1 (SstI) in the 3' untranslated region and 1 (-2854 G/T) in the APOC3-APOA4 intergenic region. We analyzed the associations of haplotypes and multilocus genotypes of these polymorphisms on longitudinal serum triglyceride profiles in 360 African American and 823 white subjects from the Bogalusa Heart Study. Subjects were examined from 2 to 8 times (mean +/- SD, 5.4 +/- 1.3) between 1973 and 1996, at ages ranging from 4 to 38 years, with 1978 observations in African Americans and 4465 in whites. Serum triglycerides were significantly higher among whites across all ages. Allele frequencies differed significantly between African Americans and whites at all but the APOA5 +56 C/G locus. Linkage disequilibrium among the loci was higher in whites and haplotype diversity lower: 6 haplotypes had estimated frequencies of more than 1% in African Americans, 5 in whites. Individually, all polymorphisms except APOC3 -2854 G/T showed significant associations with triglyceride levels in the full sample. However, genotype models including all 5 loci showed significant triglyceride associations for only 3 (APOC3 SstI, APOA5 -1131 T/C, and APOA5 +56 C/G); significant interactions among them indicated their effects were not independent. Neither APOC3 -2854 G/T nor APOA5 -3 A/G had significant effects when the other 3 loci were in the models. The EM algorithm was used to estimate haplotype frequencies and assign haplotype probabilities to individuals, which is conditional on their genotypes; individuals' haplotype probability vectors were then used as predictors in multilevel mixed models of longitudinal triglyceride profiles. Of haplotypes comprising, in order, APOC3 SstI and -2854 G/T and APOA5 -1131 T/C, -3 A/G, and +56 C/G, 3 were significantly associated with higher triglycerides, even after adjusting for multiple tests: GGTAG (P = .002), GTTAG (P < .0001), and CGCGC (P = .0002). Each GGTAG haplotype carried would be expected to raise triglyceride levels (relative to those of GTTAC homozygotes) by approximately 19 mg/dL, each GTTAG haplotype by approximately 15 mg/dL, and each CGCGC haplotype by approximately 7 mg/dL. Haplotypes comprising the 3 loci implicated by genotype analyses (SstI, -1131 T/C, and +56 C/G) were also tested: haplotypes C_C_C and G_T_G significantly raised triglycerides, even after adjustment for multiple comparisons (P < .002 for both), with each copy of C_C_C expected to raise triglycerides by approximately 7 mg/dL and each copy of G_T_G by approximately 15 mg/dL. Overall, our findings support those of others in associating specific polymorphisms and haplotypes in the APOA1/C3/A4/A5 gene cluster with higher serum triglyceride levels. However, the degree to which polymorphisms in the APOC3 and APOA5 genes may be independently associated with triglyceride levels remains to be determined.
Collapse
Affiliation(s)
- D Michael Hallman
- Human Genetics Center, University of Texas, Houston Health Science Center, Houston, TX 77225, USA.
| | | | | | | | | |
Collapse
|
150
|
Wood RJ. Effect of Dietary Carbohydrate Restriction With and Without Weight Loss on Atherogenic Dyslipidemia. Nutr Rev 2006; 64:539-45. [PMID: 17274496 DOI: 10.1111/j.1753-4887.2006.tb00187.x] [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: 02/02/2023] Open
Abstract
Increasing evidence suggests a role for carbohydrate restriction in the dietary treatment of atherogenic dyslipidemia. The effects of carbohydrate restriction on the specific aspects of lipoprotein metabolism affected by atherogenic dyslipidemia under weight-stable and weight-loss conditions are reviewed here.
Collapse
Affiliation(s)
- Richard J Wood
- Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut, USA.
| |
Collapse
|