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Gaikwad DD, Bangar NS, Apte MM, Gvalani A, Tupe RS. Mineralocorticoid interaction with glycated albumin downregulates NRF - 2 signaling pathway in renal cells: Insights into diabetic nephropathy. Int J Biol Macromol 2022; 220:837-851. [PMID: 35987363 DOI: 10.1016/j.ijbiomac.2022.08.095] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/30/2022] [Accepted: 08/13/2022] [Indexed: 12/20/2022]
Abstract
In diabetic nephropathy, hyperglycemia elevates albumin glycation and also results in increased plasma aldosterone. Both glycation and aldosterone are reported to cause oxidative stress by downregulating the NRF-2 pathway and thereby resulting in reduced levels of antioxidants and glycation detoxifying enzymes. We hypothesize that an interaction between aldosterone and glycated albumin may be responsible for amplified oxidative stress and concomitant renal cell damage. Hence, human serum albumin was glycated by methylglyoxal (MGO) in presence of aldosterone. Different structural modifications of albumin, functional modifications and aldosterone binding were analyzed. HEK-293 T cells were treated with aldosterone+glycated albumin along with inhibitors of receptors for mineralocorticoid (MR) and advanced glycation endproducts (RAGE). Cellular MGO content, antioxidant markers (nitric oxide, glutathione, catalase, superoxide dismutase, glutathione peroxidase), detoxification enzymes (aldose reductase, Glyoxalase I, II), their expression along with NRF-2 and Keap-1 were measured. Aldosterone binds to albumin with high affinity which is static and spontaneous. Cell treatment by aldosterone+glycated albumin increased intracellular MGO, MR and RAGE expression; hampered antioxidant, detoxification enzyme activities and reduced NRF-2, Keap-1 expression. Thus, the glycated albumin-aldosterone interaction and its adverse effect on renal cells were confirmed. The results will help in developing better pharmacotherapeutic strategies for diabetic nephropathy.
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Affiliation(s)
- Deepesh D Gaikwad
- Symbiosis School of Biological Sciences (SSBS), Symbiosis International (Deemed University) (SIU), Lavale, Pune, Maharashtra State, India
| | - Nilima S Bangar
- Symbiosis School of Biological Sciences (SSBS), Symbiosis International (Deemed University) (SIU), Lavale, Pune, Maharashtra State, India
| | - Mayura M Apte
- Symbiosis School of Biological Sciences (SSBS), Symbiosis International (Deemed University) (SIU), Lavale, Pune, Maharashtra State, India
| | - Armaan Gvalani
- Symbiosis School of Biological Sciences (SSBS), Symbiosis International (Deemed University) (SIU), Lavale, Pune, Maharashtra State, India
| | - Rashmi S Tupe
- Symbiosis School of Biological Sciences (SSBS), Symbiosis International (Deemed University) (SIU), Lavale, Pune, Maharashtra State, India.
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Růžička M, Koval D, Vávra J, Reyes-Gutiérrez PE, Teplý F, Kašička V. Interactions of helquats with chiral acidic aromatic analytes investigated by partial-filling affinity capillary electrophoresis. J Chromatogr A 2016; 1467:417-426. [PMID: 27578406 DOI: 10.1016/j.chroma.2016.08.053] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 08/20/2016] [Accepted: 08/24/2016] [Indexed: 01/18/2023]
Abstract
Noncovalent molecular interactions between helquats, a new class of dicationic helical extended diquats, and several chiral acidic aromatic drugs and catalysts have been investigated using partial-filling affinity capillary electrophoresis (PF-ACE). Helquats dissolved at 1mM concentration in the aqueous background electrolyte (40mM Tris, 20mM acetic acid, pH 8.1) were introduced as ligand zones of variable length (0-130mm) into the hydroxypropylcellulose coated fused silica capillary whereas 0.1mM solutions of negatively charged chiral drugs or catalysts (warfarin, ibuprofen, mandelic acid, etodolac, binaphthyl phosphate and 11 other acidic aromatic compounds) were applied as a short analyte zone at the injection capillary end. After application of electric field, analyte and ligand migrated against each other and in case of their interactions, migration time of the analyte was increasing with increasing length of the ligand zone. From the tested compounds, only isomers of those exhibiting helical chirality and/or possessing conjugated aromatic systems were enantioselectively separated through their differential interactions with helquats. Some compounds with conjugated aromatic groups interacted with helquats moderately strongly but non-enantiospecifically. Small compounds with single benzene ring exhibited no or very weak non-enantiospecific interactions. PF-ACE method allowed to determine binding constants of the analyte-helquat complexes from the changes of migration times of the analytes. Binding constants of the weakest complexes of the analytes with helquats were less than 50L/mol, whereas binding constants of the strongest complexes were in the range 1 000-1 400L/mol.
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Affiliation(s)
- Martin Růžička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám., 542/2, 166 10 Prague 6, Czech Republic; Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Dušan Koval
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám., 542/2, 166 10 Prague 6, Czech Republic
| | - Jan Vávra
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám., 542/2, 166 10 Prague 6, Czech Republic
| | - Paul E Reyes-Gutiérrez
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám., 542/2, 166 10 Prague 6, Czech Republic
| | - Filip Teplý
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám., 542/2, 166 10 Prague 6, Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo nám., 542/2, 166 10 Prague 6, Czech Republic.
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Chanphai P, Vesper AR, Bariyanga J, Bérubé G, Tajmir-Riahi HA. Review on the delivery of steroids by carrier proteins. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 161:184-91. [PMID: 27261699 DOI: 10.1016/j.jphotobiol.2016.05.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 05/11/2016] [Accepted: 05/17/2016] [Indexed: 12/20/2022]
Abstract
Due to the poor solubility of steroids in aqueous solution, delivery of these biomaterials is of major biomedical importance. We have reviewed the conjugation of testosterone and it aliphatic dimer and aromatic dimer with several carrier proteins, human serum albumin (HSA), bovine serum albumin (BSA) and milk beta-lactoglobulin (b-LG) in aqueous solution at physiological pH. The results of multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were compared here. Steroid-protein bindings are via hydrophilic and H-bonding contacts. HSA forms more stable conjugate than BSA and b-LG. The stability of steroid-protein conjugates is testosterone>dimer-aromatic>dimer-aliphatic. Encapsulation of steroids by protein is shown by TEM images. Modeling showed the presence of H-bonding, which stabilized testosterone-protein complexes with the free binding energy of -12.95 for HSA and -11.55 for BSA and -8.92kcal/mol for b-LG conjugates. Steroid conjugation induced major perturbations of serum protein conformations. Serum proteins can transport steroids to the target molecules.
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Affiliation(s)
- P Chanphai
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, Québec G9A 5H7, Canada
| | - A R Vesper
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, Québec G9A 5H7, Canada
| | - J Bariyanga
- Division of Humanities: Math/Sciences, University of Hawaii-West O'ahu, 1001 Farrington Highway, Kapolei, HI 96707, USA
| | - G Bérubé
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, Québec G9A 5H7, Canada
| | - H A Tajmir-Riahi
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, Québec G9A 5H7, Canada.
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Zheng X, Bi C, Brooks M, Hage DS. Analysis of Hormone-Protein Binding in Solution by Ultrafast Affinity Extraction: Interactions of Testosterone with Human Serum Albumin and Sex Hormone Binding Globulin. Anal Chem 2015; 87:11187-94. [PMID: 26484387 DOI: 10.1021/acs.analchem.5b03007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ultrafast affinity extraction was used to study hormone-protein interactions in solution, using testosterone and its transport proteins human serum albumin (HSA) and sex hormone binding globulin (SHBG) as models. Both single column and two-dimensional systems based on HSA microcolumns were utilized to measure the free fraction of testosterone in hormone/protein mixtures at equilibrium or that were allowed to dissociate for various lengths of time. These data were used to determine the association equilibrium constants (Ka) or global affinities (nKa') and dissociation rate constants (kd) for testosterone with soluble HSA and SHBG. This method was also used to measure simultaneously the free fraction of testosterone and its equilibrium constants with both these proteins in physiological mixtures of these agents. The kd and Ka values obtained for HSA were 2.1-2.2 s(-1) and 3.2-3.5 × 10(4) M(-1) at pH 7.4 and 37 °C. The corresponding constants for SHBG were 0.053-0.058 s(-1) and 0.7-1.2 × 10(9) M(-1). All of these results gave good agreement with literature values, indicating that this approach could provide information on a wide range of rate constants and binding strengths for hormone-protein interactions in solution and at clinically relevant concentrations. The same method could be extended to alternative hormone-protein systems or other solutes and binding agents.
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Affiliation(s)
- Xiwei Zheng
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Cong Bi
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Marissa Brooks
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - David S Hage
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
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Chanphai P, Vesper AR, Bekale L, Bérubé G, Tajmir-Riahi HA. Transporting testosterone and its dimers by serum proteins. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2015; 153:173-83. [PMID: 26410041 DOI: 10.1016/j.jphotobiol.2015.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/03/2015] [Accepted: 09/09/2015] [Indexed: 11/28/2022]
Abstract
A substantial part of steroids is bound to serum proteins in vivo. We report the association of testosterone and it aliphatic dimer (alip) and aromatic dimer (arom) with human serum albumin (HSA) and bovine serum albumin (BSA) in aqueous solution at physiological pH. Multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were used to characterize steroid-protein binding and protein aggregation process. Spectroscopic analysis showed that steroids bind protein via hydrophobic, hydrophilic and H-bonding interactions. HSA forms more stable complexes than BSA. The binding affinity of steroid-protein adducts is testosterone>dimer-aromatic>dimer-aliphatic. Transmission electron microscopy showed major changes in protein morphology as steroid-protein complexation occurred with increase in the diameter of the protein aggregate indicating encapsulation of steroids by serum proteins. Modeling showed the presence of H-bonding stabilized testosterone-protein complexes with the free binding energy of -12.95 for HSA and -11.55 kcal/mol for BSA, indicating that the interaction process is spontaneous at room temperature. Steroid complexation induced more perturbations of BSA conformation than HSA.
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Affiliation(s)
- P Chanphai
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, QC G9A 5H7, Canada
| | - A R Vesper
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, QC G9A 5H7, Canada
| | - L Bekale
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, QC G9A 5H7, Canada
| | - G Bérubé
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, QC G9A 5H7, Canada
| | - H A Tajmir-Riahi
- Department of Chemistry, Biochemistry and Physics, University of Québec at Trois-Rivières, C. P. 500, Trois-Rivières, QC G9A 5H7, Canada.
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Chanphai P, Vesper AR, Bekale L, Bérubé G, Tajmir-Riahi HA. Encapsulation of testosterone and its aliphatic and aromatic dimers by milk beta-lactoglobulin. Int J Biol Macromol 2015; 76:153-60. [PMID: 25725333 DOI: 10.1016/j.ijbiomac.2015.02.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 02/17/2015] [Accepted: 02/18/2015] [Indexed: 01/24/2023]
Abstract
The encapsulation of testosterone and it aliphatic dimer (alip) and aromatic dimer (arom) with milk β-lactoglobulin (β-LG) was studied in aqueous solution at pH 7.4. Multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were used to characterize testosterone-β-LG binding and protein aggregation process. Spectroscopic analysis showed that steroids bind β-LG via hydrophobic and H-bonding interactions with overall binding constants K test-β-LG = 5.6 (± 0.6) × 10(4)M(-1), K test-dimeralip-β-LG = 4.8 (± 0.5) × 10(3)M(-1) and K test-dimer-arom-β-LG = 2.9 (± 0.4) × 10(4)M(-1). The binding affinity was testosterone > testosterone dimer-aromatic > testosterone dimer-aliphatic. Transmission electron microscopy showed major changes in protein morphology as testosterone-protein complexation occurred with increase in the diameter of the protein aggregate indicating encapsulation of steroids by β-LG. Modeling showed the presence of H-bonding stabilized testosterone-β-LG complexes with the free binding energy of -9.82 Kcal/mol indicating that the interaction process is spontaneous at room temperature.
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Affiliation(s)
- P Chanphai
- Department of Chemistry-Biochemistry and Physics, University of Québec at Trois-Riviéres C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada
| | - A R Vesper
- Department of Chemistry-Biochemistry and Physics, University of Québec at Trois-Riviéres C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada
| | - L Bekale
- Department of Chemistry-Biochemistry and Physics, University of Québec at Trois-Riviéres C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada
| | - G Bérubé
- Department of Chemistry-Biochemistry and Physics, University of Québec at Trois-Riviéres C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada
| | - H A Tajmir-Riahi
- Department of Chemistry-Biochemistry and Physics, University of Québec at Trois-Riviéres C. P. 500, Trois-Rivières, Québec, G9A 5H7, Canada.
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7
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Růžička M, Čížková M, Jirásek M, Teplý F, Koval D, Kašička V. Study of deoxyribonucleic acid-ligand interactions by partial filling affinity capillary electrophoresis. J Chromatogr A 2014; 1349:116-21. [PMID: 24861783 DOI: 10.1016/j.chroma.2014.04.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 04/17/2014] [Accepted: 04/21/2014] [Indexed: 11/17/2022]
Abstract
In this work, a new partial filling affinity capillary electrophoresis (PF-ACE) method has been developed and applied to investigation of non-covalent molecular interactions between double stranded DNA oligonucleotide (Dickerson dodecamer) and classical DNA intercalator ligand-ethidiumbromide (EtBr) or oligophenylene derivatives-based potential new type of DNA ligands. Binding constants of DNA-ligand complexes were determined from the dependence of migration time changes of DNA oligomer (applied as analyte) on the length of ligand zones introduced beforehand as plugs of various lengths (0-75mm with 12.5mm step) in hydroxypropylcellulose coated fused silica capillary of 50/375μm I.D./O.D. and 400/300mm total/effective length. PF-ACE experiments were performed in two background electrolytes, Tris-borate, pH 8.0, ionic strength 14.3mM (BGE1), and sodium phosphate, pH 7.5, ionic strength 133mM (BGE2). Binding constants of DNA-EtBr complex (ca 15300L/mol in the BGE1 and 4200L/mol in the BGE2) were found to be significantly higher than those of DNA complexes with oligophenylene derivatives (ca 2200-3600L/mol in the BGE1 and 1600-2300L/mol in the BGE2).
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Affiliation(s)
- Martin Růžička
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic; Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Prague 2, Czech Republic
| | - Martina Čížková
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic
| | - Michael Jirásek
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic
| | - Filip Teplý
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic
| | - Dušan Koval
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo 2, 166 10 Prague 6, Czech Republic.
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Lakshman KM, Kaplan B, Travison TG, Basaria S, Knapp PE, Singh AB, LaValley MP, Mazer NA, Bhasin S. The effects of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in young and older men. J Clin Endocrinol Metab 2010; 95:3955-64. [PMID: 20534765 PMCID: PMC2913038 DOI: 10.1210/jc.2010-0102] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND During testosterone (T) therapy, T is partly converted to 17beta-estradiol (E2) and 5alpha-dihydrotestosterone (DHT). Effects of age, testosterone dose, and body composition on total and free E2 and DHT levels are unknown. OBJECTIVE We evaluated age and dose-related differences in E2 and DHT levels in response to graded doses of testosterone enanthate in young and older men. METHODS Fifty-one young (aged 19-35 yr) and 52 older (aged 59-75 yr) men completed treatment with monthly injections of a GnRH agonist plus randomly assigned weekly doses of testosterone enanthate (25, 50, 125, 300, or 600 mg) for 5 months. RESULTS During testosterone administration, total and free E2 levels increased dose-dependently (dose effect, P<0.001) in both young and older men. Total and free E2 levels and E2:T ratios during T administration were higher in older than young men, but age-related differences in free E2 and free E2:T ratios were not significant after adjusting for testosterone levels, percentage fat mass, and SHBG. DHT levels and DHT:T ratios were dose-related but did not differ between young and older men. Mechanistic modeling of free hormone data revealed that the conversions of T to E2 and DHT were both consistent with saturable Michaelis-Menten kinetics. The in vivo Km values were estimated to be 1.83 nm for aromatase and 3.35 nm for 5alpha-reductase, independent of age. The Vmax parameter for E2 was 40% higher in older men than younger men, but Vmax for DHT was not significantly different between age groups. CONCLUSIONS During im testosterone administration, E2 and DHT levels exhibit saturable increases with dose. The rate of whole body aromatization is higher in older men, partly related to their higher percentage fat mass, SHBG, and testosterone levels.
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Affiliation(s)
- Kishore M Lakshman
- Division of Endocrinology, Diabetes and Nutrition, Boston Claude D. Pepper Older Americans Independence Center for Function Promoting Therapies, Boston University School of Medicine, Boston Medical Center, 670 Albany Street, Second Floor, Boston, Massachusetts 02118, USA.
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Francis GL. Albumin and mammalian cell culture: implications for biotechnology applications. Cytotechnology 2010; 62:1-16. [PMID: 20373019 PMCID: PMC2860567 DOI: 10.1007/s10616-010-9263-3] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Accepted: 03/10/2010] [Indexed: 12/15/2022] Open
Abstract
Albumin has a long historical involvement in design of media for the successful culture of mammalian cells, in both the research and commercial fields. The potential application of albumins, bovine or human serum albumin, for cell culture is a by-product of the physico-chemical, biochemical and cell-specific properties of the molecule. In this review an analysis of these features of albumin leads to a consideration of the extracellular and intracellular actions of the molecule, and importantly the role of its interactions with numerous ligands or bioactive factors that influence the growth of cells in culture: these include hormones, growth factors, lipids, amino acids, metal ions, reactive oxygen and nitrogen species to name a few. The interaction of albumin with the cell in relation to these co-factors has a potential impact on metabolic and biosynthetic activity, cell proliferation and survival. Application of this knowledge to improve the performance in manufacturing biotechnology and in the emerging uses of cell culture for tissue engineering and stem cell derived therapies is an important prospect.
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Affiliation(s)
- Geoffrey L Francis
- Applied R&D, Novozymes Biopharma AU Ltd, 28 Dalgleish Street, Thebarton, SA, 5031, Australia,
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Chernov'yants MS, Dolinkin AO, Chernyshev AV, Khohlov EV, Golovanova EG. Interaction of Antithyroid Drugs with Bovine Serum Albumin: Electrophoretic and Fluorimetric Study. J Pharm Sci 2010; 99:1567-73. [DOI: 10.1002/jps.21915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
This review attempts to give a synopsis of the major aspects concerning the biochemistry of endogenous androgens, supplemented with several facets of physiology, particularly with respect to testosterone. Testosterone continues to be the most common adverse finding declared by World Anti-Doping Agency accredited laboratories, such samples having an augmented testosterone to epitestosterone ratio. Knowledge regarding the precursors and metabolism of endogenous testosterone is therefore fundamental to understanding many of the issues concerning doping with testosterone and its prohormones, including the detection of their administration. Further, adverse findings for nandrolone are frequent, but this steroid and 19-norandrostenedione are also produced endogenously, an appealing hypothesis being that they are minor by-products of the aromatization of androgens. At sports tribunals pertaining to adverse analytical findings of natural androgen administration, experts often raise issues that concern some aspect of steroid biochemistry and physiology. Salient topics included within this review are the origins and interconversion of endogenous androgens, the biosynthesis of testosterone and epitestosterone, the mechanism of aromatization, the molecular biology of the androgen receptor, the hypothalamic-pituitary-testicular axis, disturbances to this axis by anabolic steroid administration, the transport (binding) of androgens in blood, and briefly the metabolism and excretion of androgens.
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He T, Liang Q, Wang Y, Luo G. CHARACTERIZATION OF THE INTERACTIONS BETWEEN NATURAL FLAVONOID COMPOUNDS AND BOVINE SERUM ALBUMIN BY CAPILLARY ELECTROPHORESIS AND FLUORESCENCE METHOD. J LIQ CHROMATOGR R T 2010. [DOI: 10.1080/10826070903574626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Tianxi He
- a Department of Chemistry , Tsinghua University , Beijing, P. R. China
- b Logistic Engineering of University , Chongqing, P. R. China
| | - Qionglin Liang
- a Department of Chemistry , Tsinghua University , Beijing, P. R. China
| | - Yiming Wang
- a Department of Chemistry , Tsinghua University , Beijing, P. R. China
| | - Guoan Luo
- a Department of Chemistry , Tsinghua University , Beijing, P. R. China
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Chu BL, Lin JM, Wang Z, Guo B. Enantiospecific binding of Rotigotine and its antipode to serum albumins: Investigation of binding constants and binding sites by partial-filling ACE. Electrophoresis 2009; 30:2845-52. [DOI: 10.1002/elps.200800521] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kostal V, Katzenmeyer J, Arriaga EA. Capillary electrophoresis in bioanalysis. Anal Chem 2008; 80:4533-50. [PMID: 18484738 DOI: 10.1021/ac8007384] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Vratislav Kostal
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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