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Variations in the Human Serum Albumin Gene: Molecular and Functional Aspects. Int J Mol Sci 2022; 23:ijms23031159. [PMID: 35163085 PMCID: PMC8835714 DOI: 10.3390/ijms23031159] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 01/14/2023] Open
Abstract
The human albumin gene, the most abundant serum protein, is located in the long arm of chromosome 4, near the centromere, position 4q11–3. It is divided by 14 intervening introns into 15 exons, the last of which is untranslated. To date, 74 nucleotide substitutions (mainly missense) have been reported, determining the circulating variants of albumin or pre-albumin. In a heterozygous state, this condition is known as alloalbuminaemia or bisalbuminaemia (OMIM # 103600). The genetic variants are not associated with disease, neither in the heterozygous nor in the homozygous form. Only the variants resulting in familial dysalbuminaemic hyperthyroxinaemia and hypertriiodothyroninaemia are of clinical relevance because affected individuals are at risk of inappropriate treatment or may have adverse drug effects. In 28 other cases, the pathogenic variants (mainly affecting splicing, nonsense, and deletions), mostly in the homozygous form, cause a premature stop in the synthesis of the protein and lead to the condition known as congenital analbuminaemia. In this review, we will summarize the current knowledge of genetic and molecular aspects, functional consequences and potential therapeutic uses of the variants. We will also discuss the molecular defects resulting in congenital analbuminaemia, as well as the biochemical and clinical features of this rare condition
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Yamamoto A, Yasue Y, Takahashi Y, Takakura Y. Determining The Role of Surface Glycans in The Pharmacokinetics of Small Extracellular Vesicles. J Pharm Sci 2021; 110:3261-3267. [PMID: 34090899 DOI: 10.1016/j.xphs.2021.05.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/29/2021] [Accepted: 05/29/2021] [Indexed: 12/19/2022]
Abstract
Small extracellular vesicles (sEVs) are important mediators of intercellular communication and are thereby expected to be promising carriers for drug delivery. Understanding the factors that affect sEV pharmacokinetics is crucial for its application as a drug delivery carrier. In this study, the role of sEV surface glycans was investigated by evaluating the effects of enzymatic deglycosylation treatment on sEV pharmacokinetics. First, control glycoprotein fetuin was used to optimize the glycosidase treatment conditions. B16-BL6-derived sEVs labeled with fusion proteins comprising Gag protein and Gaussia luciferase (gLuc) (Gag-gLuc) were then treated with glycosidases, Peptide-N-Glycosidase F or O-glycosidase, which cleaves N- and O-glycans, respectively. Glycosidase-treated sEVs showed physicochemical characteristics comparable to those of the untreated sEVs. However, removal of N-glycans from B16-BL6 sEVs enhanced cellular uptake by the peritoneal macrophages, while the removal of O-glycans had minimal impact, as evaluated by flow cytometry. To determine the effect of surface glycans on the sEV pharmacokinetics, Gag-gLuc labeled B16-BL6 sEVs treated with or without glycosidases were then intravenously administered to mice. Glycosidase-treated sEVs showed almost identical clearance from the blood circulation as that of the untreated sEVs. These results suggest minimal impact of surface glycans on sEV pharmacokinetics, despites its effect on cellular uptake.
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Affiliation(s)
- Aki Yamamoto
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yukari Yasue
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuki Takahashi
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Yoshinobu Takakura
- Department of Biopharmaceutics and Drug Metabolism, Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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Pilati D, Howard KA. Albumin-based drug designs for pharmacokinetic modulation. Expert Opin Drug Metab Toxicol 2020; 16:783-795. [DOI: 10.1080/17425255.2020.1801633] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Diego Pilati
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C Denmark
| | - Kenneth A. Howard
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C Denmark
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Leblanc Y, Berger M, Seifert A, Bihoreau N, Chevreux G. Human serum albumin presents isoform variants with altered neonatal Fc receptor interactions. Protein Sci 2020; 28:1982-1992. [PMID: 31583777 DOI: 10.1002/pro.3733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/09/2019] [Accepted: 09/18/2019] [Indexed: 12/23/2022]
Abstract
Human serum albumin (HSA) is the most abundant protein in plasma and presents the particularity, with IgG, to have an extraordinary long serum half-life conferred by its interaction with the neonatal Fc receptor (FcRn). If the impact of IgG post-translational modifications (PTMs) on FcRn binding is well documented, it is far less reported for HSA despite numerous PTMs occurring on the protein in plasma. HSA is susceptible to numerous degradation reactions in plasma, because of aging, oxidative stress or liver and pancreas related pathologies. In the present study, we combined FcRn affinity chromatography and mass spectrometry to investigate the impact of HSA PTMs upon FcRn binding. This methodology presents the advantage to distinguish the effect of a single modification from a plasma HSA preparation made of a mixture of different isoforms. Cys34 oxidation, Lys525 glycation, and Leu585 C-terminal truncation, which are modifications related to several pathological conditions, were demonstrated to act negatively on HSA-FcRn interaction. The HSA-FcRn binding alteration generated by these modifications is consistent with their vicinity with the interaction interface of the two proteins. Results were discussed regarding altered half-life of HSA observed in several disease states and pave the way toward new understandings of the hypoalbuminemia pathogenesis. SIGNIFICANCE STATEMENT: In this study, we investigated the impact of several post-translational modifications of HSA toward its ability to bind to the neonatal Fc receptor using in vitro affinity chromatography, mass spectrometry, and surface plasmon resonance. Cys34 oxidation, Lys525 glycation, and Leu585 C-terminal truncation were demonstrated to decrease HSA-FcRn binding. These modifications occurring in circulating HSA were discussed in relation to several pathologies as well as for the use of HSA as a therapeutic protein.
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Affiliation(s)
- Yann Leblanc
- Analytical Department of LFB Biotechnologies, Courtabœuf, France
| | - Marie Berger
- Analytical Department of LFB Biotechnologies, Courtabœuf, France
| | | | - Nicolas Bihoreau
- Analytical Department of LFB Biotechnologies, Courtabœuf, France
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An intact C-terminal end of albumin is required for its long half-life in humans. Commun Biol 2020; 3:181. [PMID: 32313072 PMCID: PMC7171077 DOI: 10.1038/s42003-020-0903-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/17/2020] [Indexed: 12/19/2022] Open
Abstract
Albumin has an average plasma half-life of three weeks and is thus an attractive carrier to improve the pharmacokinetics of fused therapeutics. The half-life is regulated by FcRn, a cellular receptor that protects against intracellular degradation. To tailor-design the therapeutic use of albumin, it is crucial to understand how structural alterations in albumin affect FcRn binding and transport properties. In the blood, the last C-terminal residue (L585) of albumin may be enzymatically cleaved. Here we demonstrate that removal of the L585 residue causes structural stabilization in regions of the principal FcRn binding domain and reduces receptor binding. In line with this, a short half-life of only 3.5 days was measured for cleaved albumin lacking L585 in a patient with acute pancreatitis. Thus, we reveal the structural requirement of an intact C-terminal end of albumin for a long plasma half-life, which has implications for design of albumin-based therapeutics. Nilsen et al. show that structural alterations in the last C-terminal α-helix of albumin strongly reduce its binding to the neonatal Fc receptor, decreasing the half-life of albumin in humans. This study suggests the structural requirement of the C-terminal of albumin for its long plasma half-life, providing insights into the design of albumin used to carry drugs.
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Intrinsically Disordered Regions in Serum Albumin: What Are They For? Cell Biochem Biophys 2017; 76:39-57. [PMID: 28281231 DOI: 10.1007/s12013-017-0785-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/13/2017] [Indexed: 12/16/2022]
Abstract
Serum albumin is a major plasma protein in mammalian blood. The importance of this protein lies in its roles in both bioregulation and transport phenomena. Serum albumin binds various metal ions and participates in the transport and storage of fatty acids, bilirubin, steroids amino acids, and many other ligands, usually with regions of hydrophobic surface. Although the primary role of serum albumin is to transport various ligand, its versatile binding capacities and high concentration mean that it can assume a number of additional functions. The major goal of this article is to show how intrinsic disorder is encoded in the amino acid sequence of serum albumin, and how intrinsic disorder is related to functions of this important serum protein.
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Kouno Y, Anraku M, Yamasaki K, Okayama Y, Iohara D, Nakamura H, Maruyama T, Hirayama F, Kragh-Hansen U, Otagiri M. N-acetyl-L-methionine is a superior protectant of human serum albumin against post-translational oxidation as compared to N-acetyl-L-tryptophan. Biochem Biophys Rep 2016; 6:266-274. [PMID: 28955884 PMCID: PMC5600351 DOI: 10.1016/j.bbrep.2016.04.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/20/2016] [Accepted: 04/25/2016] [Indexed: 12/25/2022] Open
Abstract
Sodium octanoate and N-acetyl-L-tryptophan (N-AcTrp) are widely used as stabilizers during pasteurization and storage of albumin products. However, as compared with N-AcTrp, N-acetyl-L-methionine (N-AcMet) is superior in protecting albumin exposed to light during storage. Here, we examine, whether N-AcMet also is better than N-AcTrp to protect albumin against oxidation. Recombinant human serum albumin (rHSA) without and with N-AcMet or N-AcTrp was oxidized by using chloramine-T (CT) as a model compound for mimicking oxidative stress. Oxidation of rHSA was examined by determining carbonyl groups and advanced oxidation protein products. Structural changes were studied by native-PAGE, circular dichroism, intrinsic fluorescence and differential scanning calorimetry. The anti-oxidant capacity of CT-treated rHSA was quantified by its ability to scavenge peroxynitrite and the hydroxyl radical. The pharmacokinetics of indocyanine green-labeled albumin preparations was studied in male mice. We found that the number of chemical modifications and the structural changes of rHSA were significantly smaller in the presence of N-AcMet than in the presence of N-AcTrp. The anti-oxidant properties of CT-exposed rHSA were best protected by adding N-AcMet. Finally, N-AcMet is superior in preserving the normal pharmacokinetics of rHSA. Thus, N-AcMet is superior to N-AcTrp in protecting albumin preparations against oxidation. In addition, N-AcMet is probable also useful for protecting other proteins. Therefore, N-AcMet should be useful as a new and effective stabilizer and antioxidant for albumin isolated from blood, rHSA, albumin-fusion proteins and for preparations of rHSA-therapeutic complexes.
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Affiliation(s)
- Yousuke Kouno
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan
- Pharma Daiwa Yuge Pharmacy, Kumamoto City, Japan
| | - Makoto Anraku
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan
- DDS Research Institute, Sojo University, Kumamoto 860-0082, Japan
| | - Keishi Yamasaki
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan
- DDS Research Institute, Sojo University, Kumamoto 860-0082, Japan
| | | | - Daisuke Iohara
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan
| | - Hedeaki Nakamura
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Toru Maruyama
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Fumitoshi Hirayama
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan
- DDS Research Institute, Sojo University, Kumamoto 860-0082, Japan
| | | | - Masaki Otagiri
- Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto 860-0082, Japan
- DDS Research Institute, Sojo University, Kumamoto 860-0082, Japan
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Sleep D, Cameron J, Evans LR. Albumin as a versatile platform for drug half-life extension. Biochim Biophys Acta Gen Subj 2013; 1830:5526-34. [PMID: 23639804 DOI: 10.1016/j.bbagen.2013.04.023] [Citation(s) in RCA: 331] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/16/2013] [Accepted: 04/17/2013] [Indexed: 01/10/2023]
Abstract
BACKGROUND Albumin is the most abundant plasma protein, is highly soluble, very stable and has an extraordinarily long circulatory half-life as a direct result of its size and interaction with the FcRn mediated recycling pathway. In contrast, many therapeutic molecules are smaller than the renal filtration threshold and are rapidly lost from the circulation thereby limiting their therapeutic potential. Albumin can be used in a variety of ways to increase the circulatory half-life of such molecules. SCOPE OF REVIEW This article will review the mechanisms which underpin albumin's extraordinarily long circulatory half-life and how the understanding of these processes are currently being employed to extend the circulatory half-life of drugs which can be engineered to bind to albumin, or are conjugated to, or genetically fused to, albumin. MAJOR CONCLUSIONS The recent and growing understanding of the pivotal role of FcRn in maintaining the extended circulatory half-life of albumin will necessitate a greater and more thorough investigation of suitable pre-clinical model systems for assessing the pharmacokinetic profiles of drugs associated, conjugated or fused to albumin. GENERAL SIGNIFICANCE Association, conjugation or fusion of therapeutic drugs to albumin is a well-accepted and established half-life extension technology. The manipulation of the albumin-FcRn interaction will facilitate the modulation of the circulatory half-life of albumin-enabled drugs, leading to superior pharmacokinetics tailored to the disease state and increased patient compliance. This article is part of a Special Issue entitled Serum Albumin.
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Kragh-Hansen U, Minchiotti L, Galliano M, Peters T. Human serum albumin isoforms: genetic and molecular aspects and functional consequences. Biochim Biophys Acta Gen Subj 2013; 1830:5405-17. [PMID: 23558059 DOI: 10.1016/j.bbagen.2013.03.026] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 03/21/2013] [Accepted: 03/23/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND At present, 67 different genetic variants of human serum albumin and proalbumin have been molecularly characterized at the protein and/or gene level. SCOPE OF REVIEW This review summarizes present knowledge about genetic and molecular aspects, functional consequences and potential uses of the variants. MAJOR CONCLUSIONS The frequency of bisalbuminemia in the general population is probably about 1:1000, but it can be much higher in isolated populations. Mutations are often due to hypermutable CpG dinucleotides, and in addition to single-amino acid substitutions, glycosylated variants and C-terminally modified alloalbumins have been found. Some mutants show altered stability in vivo and/or in vitro. High-affinity binding of Ni(++) and Cu(++) is blocked, or almost so, by amino acid changes at the N-terminus. In contrast, substitution of Leu90 and Arg242 leads to strong binding of triiodothyronine and l-thyroxine, respectively, resulting in two clinically important syndromes. Variants often have modified plasma half-lives and organ uptakes when studied in mice. GENERAL SIGNIFICANCE Because alloalbumins do not seem to be associated with disease, they can be used as markers of migration and provide a model for study of neutral molecular evolution. They can also give valuable molecular information about albumins binding sites, antioxidant and enzymatic properties, as well as stability. Mutants with increased affinity for endogenous or exogenous ligands could be therapeutically relevant as antidotes, both for in vivo and extracorporeal treatment. Variants with modified biodistribution could be used for drug targeting. In most cases, the desired function can be further elaborated by producing site-directed, recombinant mutants. This article is part of a Special Issue entitled Serum Albumin.
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Solá RJ, Griebenow K. Glycosylation of therapeutic proteins: an effective strategy to optimize efficacy. BioDrugs 2010; 24:9-21. [PMID: 20055529 DOI: 10.2165/11530550-000000000-00000] [Citation(s) in RCA: 323] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During their development and administration, protein-based drugs routinely display suboptimal therapeutic efficacies due to their poor physicochemical and pharmacological properties. These innate liabilities have driven the development of molecular strategies to improve the therapeutic behavior of protein drugs. Among the currently developed approaches, glycoengineering is one of the most promising, because it has been shown to simultaneously afford improvements in most of the parameters necessary for optimization of in vivo efficacy while allowing for targeting to the desired site of action. These include increased in vitro and in vivo molecular stability (due to reduced oxidation, cross-linking, pH-, chemical-, heating-, and freezing-induced unfolding/denaturation, precipitation, kinetic inactivation, and aggregation), as well as modulated pharmacodynamic responses (due to altered potencies from diminished in vitro enzymatic activities and altered receptor binding affinities) and improved pharmacokinetic profiles (due to altered absorption and distribution behaviors, longer circulation lifetimes, and decreased clearance rates). This article provides an account of the effects that glycosylation has on the therapeutic efficacy of protein drugs and describes the current understanding of the mechanisms by which glycosylation leads to such effects.
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Affiliation(s)
- Ricardo J Solá
- Laboratory for Applied Biochemistry and Biotechnology, Department of Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, Puerto Rico 00931-3346, USA.
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Otagiri M, Chuang VTG. Pharmaceutically important pre- and posttranslational modifications on human serum albumin. Biol Pharm Bull 2009; 32:527-34. [PMID: 19336879 DOI: 10.1248/bpb.32.527] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recombinant technology allows engineering and production of proteins with desirable properties. Human serum albumin has been developed with recombinant technology, and thus plays an increasing role as a drug carrier in the clinical setting. Genetic variations usually occur on the surface of the protein, and do not impose significant effects on the conformation of albumin. However, binding of fatty acids by genetic variants is affected according to the location of the mutation. Albumin undergoes three major posttranslational modifications, namely, oxidation, glycation, and S-nitrosylation. This review gives an account of the different posttranslational modifications that should be taken into consideration when designing albumin mutant analogues with desirable pharmaceutical properties.
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Affiliation(s)
- Masaki Otagiri
- Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, Japan.
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Andersen JT, Sandlie I. The Versatile MHC Class I-related FcRn Protects IgG and Albumin from Degradation: Implications for Development of New Diagnostics and Therapeutics. Drug Metab Pharmacokinet 2009; 24:318-32. [DOI: 10.2133/dmpk.24.318] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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