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Fung KYY, Ho TWW, Xu Z, Neculai D, Beauchemin CAA, Lee WL, Fairn GD. Apolipoprotein A1 and high-density lipoprotein limit low-density lipoprotein transcytosis by binding SR-B1. J Lipid Res 2024; 65:100530. [PMID: 38479648 PMCID: PMC11004410 DOI: 10.1016/j.jlr.2024.100530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 04/09/2024] Open
Abstract
Atherosclerosis results from the deposition and oxidation of LDL and immune cell infiltration in the sub-arterial space leading to arterial occlusion. Studies have shown that transcytosis transports circulating LDL across endothelial cells lining blood vessels. LDL transcytosis is initiated by binding to either scavenger receptor B1 (SR-B1) or activin A receptor-like kinase 1 on the apical side of endothelial cells leading to its transit and release on the basolateral side. HDL is thought to partly protect individuals from atherosclerosis due to its ability to remove excess cholesterol and act as an antioxidant. Apolipoprotein A1 (APOA1), an HDL constituent, can bind to SR-B1, raising the possibility that APOA1/HDL can compete with LDL for SR-B1 binding, thereby limiting LDL deposition in the sub-arterial space. To examine this possibility, we used in vitro approaches to quantify the internalization and transcytosis of fluorescent LDL in coronary endothelial cells. Using microscale thermophoresis and affinity capture, we find that SR-B1 and APOA1 interact and that binding is enhanced when using the cardioprotective variant of APOA1 termed Milano (APOA1-Milano). In male mice, transiently increasing the levels of HDL reduced the acute deposition of fluorescently labeled LDL in the atheroprone inner curvature of the aorta. Reduced LDL deposition was also observed when increasing circulating wild-type APOA1 or the APOA1-Milano variant, with a more robust inhibition from the APOA1-Milano. The results suggest that HDL may limit SR-B1-mediated LDL transcytosis and deposition, adding to the mechanisms by which it can act as an atheroprotective particle.
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Affiliation(s)
- Karen Y Y Fung
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Tse Wing Winnie Ho
- Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Zizhen Xu
- Department of Cell Biology, and Department of Pathology Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Dante Neculai
- Department of Cell Biology, and Department of Pathology Sir Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Catherine A A Beauchemin
- Department of Physics, Toronto Metropolitan University, Toronto, Ontario, Canada; Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program, RIKEN, Wako, Saitama, Japan
| | - Warren L Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
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2
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A Study on Multiple Facets of Apolipoprotein A1 Milano. Appl Biochem Biotechnol 2023:10.1007/s12010-023-04330-2. [PMID: 36689166 DOI: 10.1007/s12010-023-04330-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 01/24/2023]
Abstract
For several strategies formulated to prevent atherosclerosis, Apolipoprotein A1 Milano (ApoA1M) remains a prime target. ApoA1M has been reported to have greater efficiency in reducing the incidence of coronary artery diseases. Furthermore, recombinant ApoA1M based mimetic peptide exhibits comparatively greater atheroprotective potential, offers a hope in reducing the burden of atherosclerosis in in vivo model system. The aim of this review is to emphasize on some of the observed ApoA1M structural and functional effects that are clinically and therapeutically meaningful that might converge on the basic role of ApoA1M in reducing the chances of glycation assisted ailments in diabetes. We also hypothesize that the nonenzymatic glycation prone arginine amino acid of ApoA1 gets replaced with cysteine residue and the rate of ApoA1 glycation may decrease due to change substitution of amino acid. Therefore, to circumvent the effect of ApoA1M glycation, the related mechanism should be explored at the cellular and functional levels, especially in respective experimental disease model in vivo.
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Bhale AS, Venkataraman K. Leveraging knowledge of HDLs major protein ApoA1: Structure, function, mutations, and potential therapeutics. Biomed Pharmacother 2022; 154:113634. [PMID: 36063649 DOI: 10.1016/j.biopha.2022.113634] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/27/2022] [Accepted: 08/30/2022] [Indexed: 11/02/2022] Open
Abstract
Apolipoprotein A1 (ApoA1) is a member of the Apolipoprotein family of proteins. It's a vital protein that helps in the production of high-density lipoprotein (HDL) particles, which are crucial for reverse cholesterol transport (RCT). It also has anti-inflammatory, anti-atherogenic, anti-apoptotic, and anti-thrombotic properties. These functions interact to give HDL particles their cardioprotective characteristics. ApoA1 has recently been investigated for its potential role in atherosclerosis, diabetes, neurological diseases, cancer, and certain infectious diseases. Since ApoA1's discovery, numerous mutations have been reported that affect its structural integrity and alter its function. Hence these insights have led to the development of clinically relevant peptides and synthetic reconstituted HDL (rHDL) that mimics the function of ApoA1. As a result, this review has aimed to provide an organized explanation of our understanding of the ApoA1 protein structure and its role in various essential pathways. Furthermore, we have comprehensively reviewed the important ApoA1 mutations (24 mutations) that are reported to be involved in various diseases. Finally, we've focused on the therapeutic potentials of some of the beneficial mutations, small peptides, and synthetic rHDL that are currently being researched or developed, since these will aid in the development of novel therapeutics in the future.
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Affiliation(s)
- Aishwarya Sudam Bhale
- Centre for Bio-Separation Technology, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India
| | - Krishnan Venkataraman
- Centre for Bio-Separation Technology, Vellore Institute of Technology, Vellore 632014, Tamil Nadu, India.
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Edmunds SJ, Liébana-García R, Stenkula KG, Lagerstedt JO. A short peptide of the C-terminal class Y helices of apolipoprotein A-I has preserved functions in cholesterol efflux and in vivo metabolic control. Sci Rep 2020; 10:18070. [PMID: 33093642 PMCID: PMC7582918 DOI: 10.1038/s41598-020-75232-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022] Open
Abstract
Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) induces glucose uptake by muscle tissues and stimulates pancreatic insulin secretion, and also facilitates cholesterol transport in circulation, and is explored for anti-diabetic and anti-atherosclerotic treatments. As the better alternative to complex protein-lipid formulations it was recently established that the C-terminal region of the ApoA-I protein singly improves the metabolic control and prevents formation of atherosclerotic plaques. Additional investigations of peptides based on the ApoA-I structure may lead to novel anti-diabetic drugs. We here investigate a short peptide (33mer, RG33) that corresponds to the two last helical segments (aa 209-241) of the ApoA-I structure (so-called class Y-helices which forms amphipathic helices) for stability and solubility in serum, for in vitro cholesterol efflux capability, and for providing in vivo glucose control in an insulin resistant mouse model. The RG33 peptide efficiently solubilizes lipid-vesicles, and promotes the efflux of cholesterol from cultured macrophages. The efflux capacity is significantly increased in the presence of lipids compared to non-lipidated RG33. Finally, acute treatment with the RG33 peptide significantly improves the glucose clearance capacity of insulin resistant mice. The impact of the RG33 peptide on glucose control and cholesterol transport, as well as the physicochemical properties, makes it a good candidate for translational exploration of its therapeutic potential in diabetes treatment.
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Affiliation(s)
- Shelley J Edmunds
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden
| | - Rebeca Liébana-García
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden
| | - Karin G Stenkula
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden
| | - Jens O Lagerstedt
- Biomedical Center Floor C13, Lund University Diabetes Center, Tornavagen 10, 221 84, Lund, Sweden. .,Lund Institute of Advanced Neutron and X-ray Science (LINXS), Lund, Sweden.
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5
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Ma'arfi F, Chandra S, Fatima JE, Khan MY, Mir SS, Yusuf MA. Probing the Structure-Function relationship and amyloidogenic propensities in natural variants of apolipoprotein A-I. Biochem Biophys Rep 2020; 24:100815. [PMID: 33024841 PMCID: PMC7527581 DOI: 10.1016/j.bbrep.2020.100815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 09/09/2020] [Accepted: 09/13/2020] [Indexed: 11/25/2022] Open
Abstract
Background Apolipoprotein A-I (apoA-I) protects against atherosclerosis and participates in the removal of excess cellular cholesterol from peripheral organs. Several naturally occurring apoA-I mutations are associated with familial systemic amyloidosis, with deposition of amyloid aggregates in peripheral organs, resulting in multiple organ failure. Systematic studies on naturally occurring variants are needed to delineate their roles and involvement in pathogenesis. Methods We performed a comparative structure–function analysis of five naturally occurring apoA-I variants and the wild-type protein. Circular dichroism, Fourier-transform infrared spectroscopy, thioflavin T and congo red fluorescence assays, thermal, chemical, and proteolytic stability assays, and 1,2-Dimyristoyl-sn-glycero-3-phosphocholine clearance analyses were used to assess the effects of mutations on the structure, function, stability, aggregation, and proteolytic susceptibility of the proteins to explore the mechanisms underlying amyloidosis and hypercholesterolemia. Results We observed structural changes in the mutants independent of fibril formation, suggesting the influence of the surrounding environment. The mutants were involved in aggregate formation to varying degree; L170P, R173P, and V156E showed an increased propensity to aggregate under different physiological conditions. β sheet formation indicates that L170P and R173P participate in amyloid formation. Compared to WT, V156E and L170P exhibited higher capacity for lipid clearance. Conclusions The selected point mutations, including those outside the hot spot regions of apoA-I structure, perturb the physiochemical and conformational behavior of the protein, influencing its function. General significance The study provides insights into the structure–function relationships of naturally occurring apoA-I variants outside the hot spot mutation sites. Several apoA-I mutants are associated with systemic amyloidosis. Structure–function analysis of five apoA-I variants and wild-type protein was done. Point mutations alter the physicochemical behavior and conformation of the variants.
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Affiliation(s)
- Farah Ma'arfi
- Department of Bioengineering, Integral University, Kursi Road, Dasauli, Lucknow, 226026, India
| | - Subhash Chandra
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Jamal e Fatima
- Department of Bioengineering, Integral University, Kursi Road, Dasauli, Lucknow, 226026, India
| | - Mohd Yasir Khan
- Department of Biosciences, Integral University, Kursi Road, Dasauli, Lucknow, 226026, India
| | - Snober S. Mir
- Department of Bioengineering, Integral University, Kursi Road, Dasauli, Lucknow, 226026, India
| | - Mohd Aslam Yusuf
- Department of Bioengineering, Integral University, Kursi Road, Dasauli, Lucknow, 226026, India
- Corresponding author. ;
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6
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Fritzen AM, Domingo-Espín J, Lundsgaard AM, Kleinert M, Israelsen I, Carl CS, Nicolaisen TS, Kjøbsted R, Jeppesen JF, Wojtaszewski JFP, Lagerstedt JO, Kiens B. ApoA-1 improves glucose tolerance by increasing glucose uptake into heart and skeletal muscle independently of AMPKα 2. Mol Metab 2020; 35:100949. [PMID: 32244181 PMCID: PMC7082546 DOI: 10.1016/j.molmet.2020.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 01/03/2020] [Accepted: 01/24/2020] [Indexed: 12/17/2022] Open
Abstract
OBJECTIVE Acute administration of the main protein component of high-density lipoprotein, apolipoprotein A-I (ApoA-1), improves glucose uptake in skeletal muscle. The molecular mechanisms mediating this are not known, but in muscle cell cultures, ApoA-1 failed to increase glucose uptake when infected with a dominant-negative AMP-activated protein kinase (AMPK) virus. We therefore investigated whether AMPK is necessary for ApoA-1-stimulated glucose uptake in intact heart and skeletal muscle in vivo. METHODS The effect of injection with recombinant human ApoA-1 (rApoA-1) on glucose tolerance, glucose-stimulated insulin secretion, and glucose uptake into skeletal and heart muscle with and without block of insulin secretion by injection of epinephrine (0.1 mg/kg) and propranolol (5 mg/kg), were investigated in 8 weeks high-fat diet-fed (60E%) wild-type and AMPKα2 kinase-dead mice in the overnight-fasted state. In addition, the effect of rApoA-1 on glucose uptake in isolated skeletal muscle ex vivo was studied. RESULTS rApoA-1 lowered plasma glucose concentration by 1.7 mmol/l within 3 h (6.1 vs 4.4 mmol/l; p < 0.001). Three hours after rApoA-1 injection, glucose tolerance during a 40-min glucose tolerance test (GTT) was improved compared to control (area under the curve (AUC) reduced by 45%, p < 0.001). This was accompanied by an increased glucose clearance into skeletal (+110%; p < 0.001) and heart muscle (+100%; p < 0.001) and an increase in glucose-stimulated insulin secretion 20 min after glucose injection (+180%; p < 0.001). When insulin secretion was blocked during a GTT, rApoA-1 still enhanced glucose tolerance (AUC lowered by 20% compared to control; p < 0.001) and increased glucose clearance into skeletal (+50%; p < 0.05) and heart muscle (+270%; p < 0.001). These improvements occurred to a similar extent in both wild-type and AMPKα2 kinase-dead mice and thus independently of AMPKα2 activity in skeletal- and heart muscle. Interestingly, rApoA-1 failed to increase glucose uptake in isolated skeletal muscles ex vivo. CONCLUSIONS In conclusion, ApoA-1 stimulates in vivo glucose disposal into skeletal and heart muscle independently of AMPKα2. The observation that ApoA-1 fails to increase glucose uptake in isolated muscle ex vivo suggests that additional systemic effects are required.
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Affiliation(s)
- Andreas Mæchel Fritzen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, S-221 84, Lund, Sweden
| | - Anne-Marie Lundsgaard
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Maximilian Kleinert
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark; Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health, Germany
| | - Ida Israelsen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Christian S Carl
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Trine S Nicolaisen
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, S-221 84, Lund, Sweden; Lund Institute of Advanced X-ray and Neutron Science (LINXS), Lund, Sweden.
| | - Bente Kiens
- Section of Molecular Physiology, Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
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7
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Apolipoprotein A-I primes beta cells to increase glucose stimulated insulin secretion. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165613. [PMID: 31765698 DOI: 10.1016/j.bbadis.2019.165613] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 10/17/2019] [Accepted: 11/05/2019] [Indexed: 01/01/2023]
Abstract
The increase of plasma levels of high-density lipoproteins and Apolipoprotein A-I (ApoA-I), its main protein component, has been shown to have a positive action on glucose disposal in type 2 diabetic patients. The current study investigates the unexplored function of ApoA-I to prime beta cells for improved insulin secretion. INS-1E rat clonal beta cells as well as isolated murine islets were used to study the effect of ApoA-I on responsiveness of the beta cells to high glucose challenge. Confocal and transmission electron microscopy were used to dissect ApoA-I mechanisms of action. Chemical endocytosis blockers were used to understand the role of ApoA-I internalization in mediating its positive effect. Pre-incubation of beta cells and isolated murine islets with ApoA-I augmented glucose stimulated insulin secretion. This effect appeared to be due to an increased reservoir of insulin granules at the cell membrane, as confirmed by confocal and transmission electron microscopy. Moreover, ApoA-I induced pancreatic and duodenal homeobox 1 (PDX1) shuttling from the cytoplasm to the nucleus, with the subsequent increase in the proinsulin processing enzyme protein convertase 1 (PC1/3). Finally, the blockade of ApoA-I endocytosis in beta cells resulted in a loss of ApoA-I positive action on insulin secretion. The proposed mechanisms of the phenomenon here described include ApoA-I internalization into beta cells, PDX1 nuclear translocation, and increased levels of proinsulin processing enzymes. Altogether, these events lead to an increased number of insulin granules.
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8
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Edmunds SJ, Liébana-García R, Nilsson O, Domingo-Espín J, Grönberg C, Stenkula KG, Lagerstedt JO. ApoAI-derived peptide increases glucose tolerance and prevents formation of atherosclerosis in mice. Diabetologia 2019; 62:1257-1267. [PMID: 31069401 PMCID: PMC6560211 DOI: 10.1007/s00125-019-4877-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 03/13/2019] [Indexed: 01/03/2023]
Abstract
AIMS/HYPOTHESIS Finding new treatment alternatives for individuals with diabetes with severe insulin resistance is highly desired. To identify novel mechanisms that improve glucose uptake in skeletal muscle, independently from insulin levels and signalling, we have explored the therapeutic potential of a short peptide sequence, RG54, derived from apolipoprotein A-I (ApoA-I). METHODS INS-1E rat clonal beta cells, C2C12 rat muscle myotubes and J774 mouse macrophages were used to study the impact of RG54 peptide on glucose-stimulated insulin secretion, glucose uptake and cholesterol efflux, respectively. GTTs were carried out on diet-induced insulin-resistant and Leprdb diabetic mouse models treated with RG54 peptide, and the impact of RG54 peptide on atherosclerosis was evaluated in Apoe-/- mice. Control mice received ApoA-I protein, liraglutide or NaCl. RESULTS The synthetic RG54 peptide induced glucose uptake in cultured muscle myotubes by a similar amount as insulin, and also primed pancreatic beta cells for improved glucose-stimulated insulin secretion. The findings were verified in diet-induced insulin-resistant and Leprdb diabetic mice, jointly confirming the physiological effect. The RG54 peptide also efficiently catalysed cholesterol efflux from macrophages and prevented the formation of atherosclerotic plaques in Apoe-/- mice. CONCLUSIONS/INTERPRETATION The RG54 peptide exhibits good prospects for providing glucose control and reducing the risk of cardiovascular disease in individuals with severe insulin resistance.
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Affiliation(s)
- Shelley J Edmunds
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Rebeca Liébana-García
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Oktawia Nilsson
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Caitriona Grönberg
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Biomedical Center Floor C13, Lund University, Tornavagen 10, 221 84, Lund, Sweden.
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9
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Lagerstedt JO, Dalla-Riva J, Marinkovic G, Del Giudice R, Engelbertsen D, Burlin J, Petrlova J, Lindahl M, Bernfur K, Melander O, Nilsson J, Schiopu A. Anti-ApoA-I IgG antibodies are not associated with carotid artery disease progression and first-time cardiovascular events in middle-aged individuals. J Intern Med 2019; 285:49-58. [PMID: 30028049 DOI: 10.1111/joim.12817] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE IgG antibodies against apolipoprotein A-I (ApoA-I) have been found to be elevated in subjects from the general population with clinically manifest cardiovascular disease and in myocardial infarction patients with an adverse prognosis. Here, we investigated whether these antibodies are prospectively associated with carotid artery disease progression and with the risk for first-time cardiovascular events in individuals with no previous history of cardiovascular disease. APPROACH AND RESULTS We selected 383 subjects from the cardiovascular cohort of Malmö Diet and Cancer study who suffered a coronary event during a median follow-up period of 15.4 (10.3-16.4) years and 395 age- and sex-matched controls. None of the study participants had a previous history of coronary artery disease or stroke. Anti-ApoA-I IgG were measured by ELISA in serum samples collected at baseline. Intima-media thickness (IMT) was measured in the common carotid artery and in the carotid bifurcation at baseline and after 15.9 (±1.5) years. We found no associations between anti-ApoA-I IgG and carotid artery IMT at baseline or with IMT progression during follow-up. In Cox proportional hazards analyses adjusted for traditional cardiovascular risk factors, the hazard ratio (HR 95%CI) for the primary outcome, incident coronary events, was 0.97 (0.75-1.25), P = 0.782, in subjects with anti-ApoA-I IgG within the highest tertile compared with the lowest tertile. Similarly, we did not find any associations with the secondary outcome, incident first-time stroke. CONCLUSIONS Serum autoantibodies against ApoA-I do not correlate with disease progression and adverse events in cardiovascular disease-free individuals from the general population.
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Affiliation(s)
- J O Lagerstedt
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - J Dalla-Riva
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - G Marinkovic
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - R Del Giudice
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - D Engelbertsen
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - J Burlin
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - J Petrlova
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - M Lindahl
- Medical Protein Science Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - K Bernfur
- Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden
| | - O Melander
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - J Nilsson
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden
| | - A Schiopu
- Department of Clinical Sciences Malmö, Lund University, Lund, Sweden.,Department of Cardiology, Skåne University Hospital Malmö, Malmö, Sweden
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10
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Del Giudice R, Lagerstedt JO. High-efficient bacterial production of human ApoA-I amyloidogenic variants. Protein Sci 2018; 27:2101-2109. [PMID: 30291643 PMCID: PMC6237697 DOI: 10.1002/pro.3522] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/26/2018] [Accepted: 10/01/2018] [Indexed: 12/17/2022]
Abstract
Apolipoprotein A-I (ApoA-I)-related amyloidosis is a rare disease caused by missense mutations in the APOA1 gene. These mutations lead to protein aggregation and abnormal accumulation of ApoA-I amyloid fibrils in heart, liver, kidneys, skin, nerves, ovaries, or testes. Consequently, the carriers are at risk of single- or multi-organ failure and of need of organ transplantation. Understanding the basic molecular structure and function of ApoA-I amyloidogenic variants, as well as their biological effects, is, therefore, of great interest. However, the intrinsic low stability of this type of proteins makes their overexpression and purification difficult. To overcome this barrier, we here describe an optimized production and purification procedure for human ApoA-I amyloidogenic proteins that efficiently provides between 46 mg and 91 mg (depending on the protein variant) of pure protein per liter of Escherichia coli culture. Structural integrity of the amyloidogenic and native ApoA-I proteins were verified by circular dichroism spectroscopy and intrinsic fluorescence analysis, and preserved functionality was demonstrated by use of a lipid clearance assay as well as by reconstitution of high-density lipoprotein (HDL) particles. In conclusion, the use of the described high-yield protein production system to obtain amyloidogenic ApoA-I proteins, and their native counterpart, will enable molecular and cellular experimental studies aimed to explain the molecular basis for this rare disease.
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Affiliation(s)
- Rita Del Giudice
- Department of Experimental Medical ScienceLund UniversityS‐221 84LundSweden
| | - Jens O. Lagerstedt
- Department of Experimental Medical ScienceLund UniversityS‐221 84LundSweden
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11
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Björkbacka H, Yao Mattisson I, Wigren M, Melander O, Fredrikson GN, Bengtsson E, Gonçalves I, Almgren P, Lagerstedt JO, Orho-Melander M, Engström G, Nilsson J. Plasma stem cell factor levels are associated with risk of cardiovascular disease and death. J Intern Med 2017; 282:508-521. [PMID: 28842933 DOI: 10.1111/joim.12675] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Stem cell factor (SCF) is a key growth factor for several types of stem and progenitor cells. There is experimental evidence that such cells are of importance for maintaining the integrity of the cardiovascular system. We investigated the association between circulating levels of SCF and risk for development of cardiovascular events and death. METHODS SCF was analysed by the proximity extension assay technique in plasma from 4742 subjects participating in the Malmö Diet and Cancer Study. Cardiovascular events and death were monitored through national registers with a mean follow-up time of 19.2 years. RESULTS Subjects with high baseline levels of SCF had lower cardiovascular (n = 340) and all-cause mortality (n = 1159) as well as a lower risk of heart failure (n = 177), stroke (n = 318) and myocardial infarction (n = 452). Smoking, diabetes and high alcohol consumption were associated with lower levels of SCF. Single nucleotide polymorphisms in the gene region encoding PDX1 C-terminal inhibiting factor 1 (PCIF1) and matrix metalloproteinase-9 were associated with plasma SCF levels. The highest SCF quartile remained independently associated with a lower risk of a lower risk of cardiovascular [hazard ratio and 95% confidence interval 0.59 (0.43-0.81)] and all-cause mortality [0.68 (0.57-0.81)], heart failure [0.50 (0.31-0.80)] and stroke [0.66 (0.47-0.92)], but not with MI [0.96 (0.72-1.27)] as compared with the lowest quartile when adjusting for traditional cardiovascular risk factors in Cox proportional hazard regression models. CONCLUSIONS This prospective population-based study demonstrates that subjects with high levels of SCF have a lower risk of cardiovascular events and death. The findings provide clinical support for a protective role of SCF in maintaining cardiovascular integrity.
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Affiliation(s)
- H Björkbacka
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - I Yao Mattisson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - M Wigren
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - O Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - G N Fredrikson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - E Bengtsson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - I Gonçalves
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden.,Department of Cardiology - Coronary diseases, Skåne University Hospital, Malmö, Sweden
| | - P Almgren
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - J O Lagerstedt
- Department of Experimental Medical Science, Lund University, Malmö, Sweden
| | - M Orho-Melander
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - G Engström
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - J Nilsson
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
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12
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Zhu L, Petrlova J, Gysbers P, Hebert H, Wallin S, Jegerschöld C, Lagerstedt JO. Structures of apolipoprotein A-I in high density lipoprotein generated by electron microscopy and biased simulations. Biochim Biophys Acta Gen Subj 2017; 1861:2726-2738. [DOI: 10.1016/j.bbagen.2017.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/18/2017] [Accepted: 07/24/2017] [Indexed: 10/19/2022]
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13
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Synchrotron radiation circular dichroism spectroscopy reveals structural divergences in HDL-bound apoA-I variants. Sci Rep 2017; 7:13540. [PMID: 29051568 PMCID: PMC5648894 DOI: 10.1038/s41598-017-13878-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 10/03/2017] [Indexed: 12/15/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) in high-density lipoprotein (HDL) provides cardiovascular protection. Synchrotron radiation circular dichroism (SRCD) spectroscopy was used to analyze the dynamic solution structure of the apoA-I protein in the apo- and HDL-states and the protein structure conversion in HDL formation. Wild-type apoA-I protein was compared to human variants that either are protective (R173C, Milano) or lead to increased risk for ischaemic heart disease (A164S). Comparable secondary structure distributions in the HDL particles, including significant levels of beta strand/turn, were observed. ApoA-I Milano in HDL displayed larger size heterogeneity, increased protein flexibility, and an altered lipid-binding profile, whereas the apoA-I A164S in HDL showed decrease thermal stability, potentially linking the intrinsic HDL propensities of the variants to disease risk.
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14
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Del Giudice R, Domingo-Espín J, Iacobucci I, Nilsson O, Monti M, Monti DM, Lagerstedt JO. Structural determinants in ApoA-I amyloidogenic variants explain improved cholesterol metabolism despite low HDL levels. Biochim Biophys Acta Mol Basis Dis 2017; 1863:3038-3048. [PMID: 28887204 DOI: 10.1016/j.bbadis.2017.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022]
Abstract
Twenty Apolipoprotein A-I (ApoA-I) variants are responsible for a systemic hereditary amyloidosis in which protein fibrils can accumulate in different organs, leading to their failure. Several ApoA-I amyloidogenic mutations are also associated with hypoalphalipoproteinemia, low ApoA-I and high-density lipoprotein (HDL)-cholesterol plasma levels; however, subjects affected by ApoA-I-related amyloidosis do not show a higher risk of cardiovascular diseases (CVD). The structural features, the lipid binding properties and the functionality of four ApoA-I amyloidogenic variants were therefore inspected in order to clarify the paradox observed in the clinical phenotype of the affected subjects. Our results show that ApoA-I amyloidogenic variants are characterized by a different oligomerization pattern and that the position of the mutation in the ApoA-I sequence affects the molecular structure of the formed HDL particles. Although lipidation increases ApoA-I proteins stability, all the amyloidogenic variants analyzed show a lower affinity for lipids, both in vitro and in ex vivo mouse serum. Interestingly, the lower efficiency at forming HDL particles is compensated by a higher efficiency at catalysing cholesterol efflux from macrophages. The decreased affinity of ApoA-I amyloidogenic variants for lipids, together with the increased efficiency in the cholesterol efflux process, could explain why, despite the unfavourable lipid profile, patients affected by ApoA-I related amyloidosis do not show a higher CVD risk.
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Affiliation(s)
- Rita Del Giudice
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden.
| | - Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden
| | - Ilaria Iacobucci
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; CEINGE Biotecnologie Avanzate, 80145 Naples, Italy
| | - Oktawia Nilsson
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden
| | - Maria Monti
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy
| | - Daria Maria Monti
- Department of Chemical Sciences, University of Naples Federico II, 80126 Naples, Italy; Istituto Nazionale di Biostrutture e Biosistemi (INBB), Rome, Italy
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, 221 84 Lund, Sweden.
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15
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Domingo-Espín J, Lindahl M, Nilsson-Wolanin O, Cushman SW, Stenkula KG, Lagerstedt JO. Dual Actions of Apolipoprotein A-I on Glucose-Stimulated Insulin Secretion and Insulin-Independent Peripheral Tissue Glucose Uptake Lead to Increased Heart and Skeletal Muscle Glucose Disposal. Diabetes 2016; 65:1838-48. [PMID: 27207515 DOI: 10.2337/db15-1493] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/12/2016] [Indexed: 11/13/2022]
Abstract
Apolipoprotein A-I (apoA-I) of HDL is central to the transport of cholesterol in circulation. ApoA-I also provides glucose control with described in vitro effects of apoA-I on β-cell insulin secretion and muscle glucose uptake. In addition, apoA-I injections in insulin-resistant diet-induced obese (DIO) mice lead to increased glucose-stimulated insulin secretion (GSIS) and peripheral tissue glucose uptake. However, the relative contribution of apoA-I as an enhancer of GSIS in vivo and as a direct stimulator of insulin-independent glucose uptake is not known. Here, DIO mice with instant and transient blockade of insulin secretion were used in glucose tolerance tests and in positron emission tomography analyses. Data demonstrate that apoA-I to an equal extent enhances GSIS and acts as peripheral tissue activator of insulin-independent glucose uptake and verify skeletal muscle as an apoA-I target tissue. Intriguingly, our analyses also identify the heart as an important target tissue for the apoA-I-stimulated glucose uptake, with potential implications in diabetic cardiomyopathy. Explorations of apoA-I as a novel antidiabetic drug should extend to treatments of diabetic cardiomyopathy and other cardiovascular diseases in patients with diabetes.
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Affiliation(s)
- Joan Domingo-Espín
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Maria Lindahl
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | | | - Samuel W Cushman
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Karin G Stenkula
- Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Jens O Lagerstedt
- Department of Experimental Medical Science, Lund University, Lund, Sweden
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16
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Lindahl M, Petrlova J, Dalla-Riva J, Wasserstrom S, Rippe C, Domingo-Espin J, Kotowska D, Krupinska E, Berggreen C, Jones HA, Swärd K, Lagerstedt JO, Göransson O, Stenkula KG. ApoA-I Milano stimulates lipolysis in adipose cells independently of cAMP/PKA activation. J Lipid Res 2015; 56:2248-59. [PMID: 26504176 DOI: 10.1194/jlr.m054767] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Indexed: 11/20/2022] Open
Abstract
ApoA-I, the main protein component of HDL, is suggested to be involved in metabolic homeostasis. We examined the effects of Milano, a naturally occurring ApoA-I variant, about which little mechanistic information is available. Remarkably, high-fat-fed mice treated with Milano displayed a rapid weight loss greater than ApoA-I WT treated mice, and a significantly reduced adipose tissue mass, without an inflammatory response. Further, lipolysis in adipose cells isolated from mice treated with either WT or Milano was increased. In primary rat adipose cells, Milano stimulated cholesterol efflux and increased glycerol release, independently of β-adrenergic stimulation and phosphorylation of hormone sensitive lipase (Ser563) and perilipin (Ser522). Stimulation with Milano had a significantly greater effect on glycerol release compared with WT but similar effect on cholesterol efflux. Pharmacological inhibition or siRNA silencing of ABCA1 did not diminish Milano-stimulated lipolysis, although binding to the cell surface was decreased, as analyzed by fluorescence microscopy. Interestingly, methyl-β-cyclodextrin, a well-described cholesterol acceptor, dose-dependently stimulated lipolysis. Together, these results suggest that decreased fat mass and increased lipolysis following Milano treatment in vivo is partly explained by a novel mechanism at the adipose cell level comprising stimulation of lipolysis independently of the canonical cAMP/protein kinase A signaling pathway.
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Affiliation(s)
- Maria Lindahl
- Medical Protein Science, Lund University, 221 84 Lund, Sweden Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
| | - Jitka Petrlova
- Medical Protein Science, Lund University, 221 84 Lund, Sweden
| | | | | | - Catarina Rippe
- Cellular Biomechanics, Lund University, 221 84 Lund, Sweden
| | | | - Dorota Kotowska
- Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
| | - Ewa Krupinska
- Medical Protein Science, Lund University, 221 84 Lund, Sweden
| | | | - Helena A Jones
- Molecular Endocrinology, Department of Experimental Medical Science, Biomedical Center, Lund University, 221 84 Lund, Sweden
| | - Karl Swärd
- Cellular Biomechanics, Lund University, 221 84 Lund, Sweden
| | | | - Olga Göransson
- Protein Phosphorylation, Lund University, 221 84 Lund, Sweden
| | - Karin G Stenkula
- Glucose Transport and Protein Trafficking, Lund University, 221 84 Lund, Sweden
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17
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Zeno WF, Hilt S, Risbud SH, Voss JC, Longo ML. Spectroscopic Characterization of Structural Changes in Membrane Scaffold Proteins Entrapped within Mesoporous Silica Gel Monoliths. ACS APPLIED MATERIALS & INTERFACES 2015; 7:8640-8649. [PMID: 25849085 PMCID: PMC5522711 DOI: 10.1021/acsami.5b00898] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The changes in the orientation and conformation of three different membrane scaffold proteins (MSPs) upon entrapment in sol-gel-derived mesoporous silica monoliths were investigated. MSPs were examined in either a lipid-free or a lipid-bound conformation, where the proteins were associated with lipids to form nanolipoprotein particles (NLPs). NLPs are water-soluble, disk-shaped patches of a lipid bilayer that have amphiphilic MSPs shielding the hydrophobic lipid tails. The NLPs in this work had an average thickness of 5 nm and diameters of 9.2, 9.7, and 14.8 nm. We have previously demonstrated that NLPs are more suitable lipid-based structures for silica gel entrapment than liposomes because of their size compatibility with the mesoporous network (2-50 nm) and minimally altered structure after encapsulation. Here we further elaborate on that work by using a variety of spectroscopic techniques to elucidate whether or not different MSPs maintain their protein-lipid interactions after encapsulation. Fluorescence spectroscopy and quenching of the tryptophan residues with acrylamide, 5-DOXYL-stearic acid, and 16-DOXYL-stearic acid were used to determine the MSP orientation. We also utilized fluorescence anisotropy of tryptophans to measure the relative size of the NLPs and MSP aggregates after entrapment. Finally, circular dichroism spectroscopy was used to examine the secondary structure of the MSPs. Our results showed that, after entrapment, all of the lipid-bound MSPs maintained orientations that were minimally changed and indicative of association with lipids in NLPs. The tryptophan residues appeared to remain buried within the hydrophobic core of the lipid tails in the NLPs and appropriately spaced from the bilayer center. Also, after entrapment, lipid-bound MSPs maintained a high degree of α-helical content, a secondary structure associated with protein-lipid interactions. These findings demonstrate that NLPs are capable of serving as viable hosts for functional integral membrane proteins in the synthesis of sol-gel-derived bioinorganic hybrid nanomaterials.
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Affiliation(s)
- Wade F. Zeno
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California, 95616
| | - Silvia Hilt
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, California, 95616
| | - Subhash H. Risbud
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California, 95616
| | - John C. Voss
- Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, California, 95616
| | - Marjorie L. Longo
- Department of Chemical Engineering and Materials Science, University of California Davis, Davis, California, 95616
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18
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Zeno WF, Hilt S, Aravagiri K, Risbud SH, Voss JC, Parikh AN, Longo ML. Analysis of lipid phase behavior and protein conformational changes in nanolipoprotein particles upon entrapment in sol-gel-derived silica. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:9780-9788. [PMID: 25062385 PMCID: PMC4140539 DOI: 10.1021/la5025058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/24/2014] [Indexed: 06/02/2023]
Abstract
The entrapment of nanolipoprotein particles (NLPs) and liposomes in transparent, nanoporous silica gel derived from the precursor tetramethylorthosilicate was investigated. NLPs are discoidal patches of lipid bilayer that are belted by amphiphilic scaffold proteins and have an average thickness of 5 nm. The NLPs in this work had a diameter of roughly 15 nm and utilized membrane scaffold protein (MSP), a genetically altered variant of apolipoprotein A-I. Liposomes have previously been examined inside of silica sol-gels and have been shown to exhibit instability. This is attributed to their size (∼150 nm) and altered structure and constrained lipid dynamics upon entrapment within the nanometer-scale pores (5-50 nm) of the silica gel. By contrast, the dimensional match of NLPs with the intrinsic pore sizes of silica gel opens the possibility for their entrapment without disruption. Here we demonstrate that NLPs are more compatible with the nanometer-scale size of the porous environment by analysis of lipid phase behavior via fluorescence anisotropy and analysis of scaffold protein secondary structure via circular dichroism spectroscopy. Our results showed that the lipid phase behavior of NLPs entrapped inside of silica gel display closer resemblance to its solution behavior, more so than liposomes, and that the MSP in the NLPs maintain the high degree of α-helix secondary structure associated with functional protein-lipid interactions after entrapment. We also examined the effects of residual methanol on lipid phase behavior and the size of NLPs and found that it exerts different influences in solution and in silica gel; unlike in free solution, silica entrapment may be inhibiting NLP size increase and/or aggregation. These findings set precedence for a bioinorganic hybrid nanomaterial that could incorporate functional integral membrane proteins.
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Affiliation(s)
- Wade F. Zeno
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Silvia Hilt
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Kannan
K. Aravagiri
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Subhash H. Risbud
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - John C. Voss
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Atul N. Parikh
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
| | - Marjorie L. Longo
- Department
of Chemical Engineering and Materials Science and Department of
Biochemistry and Molecular Medicine, University
of California Davis, Davis, California 95616, United States
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