1
|
Lokhandwala J, Matlack JK, Smalley TB, Miner RE, Tran TH, Binning JM. Structural basis for FN3K-mediated protein deglycation. Structure 2024; 32:1711-1724.e5. [PMID: 39173621 PMCID: PMC11455621 DOI: 10.1016/j.str.2024.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 06/05/2024] [Accepted: 07/28/2024] [Indexed: 08/24/2024]
Abstract
Protein glycation is a universal, non-enzymatic modification that occurs when a sugar covalently attaches to a primary amine. These spontaneous modifications may have deleterious or regulatory effects on protein function, and their removal is mediated by the conserved metabolic kinase fructosamine-3-kinase (FN3K). Despite its crucial role in protein repair, we currently have a poor understanding of how FN3K engages or phosphorylates its substrates. By integrating structural biology and biochemistry, we elucidated the catalytic mechanism for FN3K-mediated protein deglycation. Our work identifies key amino acids required for binding and phosphorylating glycated substrates and reveals the molecular basis of an evolutionarily conserved protein repair pathway. Additional structural-functional studies revealed unique structural features of human FN3K as well as differences in the dimerization behavior and regulation of FN3K family members. Our findings improve our understanding of the structure of FN3K and its catalytic mechanism, which opens new avenues for therapeutically targeting FN3K.
Collapse
Affiliation(s)
- Jameela Lokhandwala
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Jenet K Matlack
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA; Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Tracess B Smalley
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Robert E Miner
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA; Cancer Chemical Biology PhD Program, University of South Florida, Tampa, FL 33612, USA
| | - Timothy H Tran
- Chemical Biology Core, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA
| | - Jennifer M Binning
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL 33612, USA.
| |
Collapse
|
2
|
Mossine VV, Mawhinney TP. 1-Amino-1-deoxy-d-fructose ("fructosamine") and its derivatives. Adv Carbohydr Chem Biochem 2023; 83:27-132. [PMID: 37968038 DOI: 10.1016/bs.accb.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Fructosamine has long been considered as a key intermediate of the Maillard reaction, which to a large extent is responsible for specific aroma, taste, and color formation in thermally processed or dehydrated foods. Since the 1980s, however, as a product of the Amadori rearrangement reaction between glucose and biologically significant amines such as proteins, fructosamine has experienced a boom in biomedical research, mainly due to its relevance to pathologies in diabetes and aging. In this chapter, we assess the scope of the knowledge on and applications of fructosamine-related molecules in chemistry, food, and health sciences, as reflected mostly in publications within the past decade. Methods of fructosamine synthesis and analysis, its chemical, and biological properties, and degradation reactions, together with fructosamine-modifying and -recognizing proteins are surveyed.
Collapse
Affiliation(s)
- Valeri V Mossine
- Department of Biochemistry, University of Missouri, Columbia, MO, United States
| | - Thomas P Mawhinney
- Department of Biochemistry, University of Missouri, Columbia, MO, United States.
| |
Collapse
|
3
|
De Decker I, Notebaert M, Speeckaert MM, Claes KEY, Blondeel P, Van Aken E, Van Dorpe J, De Somer F, Heintz M, Monstrey S, Delanghe JR. Enzymatic Deglycation of Damaged Skin by Means of Combined Treatment of Fructosamine-3-Kinase and Fructosyl-Amino Acid Oxidase. Int J Mol Sci 2023; 24:ijms24108981. [PMID: 37240327 DOI: 10.3390/ijms24108981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/08/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
The consensus in aging is that inflammation, cellular senescence, free radicals, and epigenetics are contributing factors. Skin glycation through advanced glycation end products (AGEs) has a crucial role in aging. Additionally, it has been suggested that their presence in scars leads to elasticity loss. This manuscript reports fructosamine-3-kinase (FN3K) and fructosyl-amino acid oxidase (FAOD) in counteracting skin glycation by AGEs. Skin specimens were obtained (n = 19) and incubated with glycolaldehyde (GA) for AGE induction. FN3K and FAOD were used as monotherapy or combination therapy. Negative and positive controls were treated with phosphate-buffered saline and aminoguanidine, respectively. Autofluorescence (AF) was used to measure deglycation. An excised hypertrophic scar tissue (HTS) (n = 1) was treated. Changes in chemical bonds and elasticity were evaluated using mid-infrared spectroscopy (MIR) and skin elongation, respectively. Specimens treated with FN3K and FAOD in monotherapy achieved an average decrease of 31% and 33% in AF values, respectively. When treatments were combined, a decrease of 43% was achieved. The positive control decreased by 28%, whilst the negative control showed no difference. Elongation testing of HTS showed a significant elasticity improvement after FN3K treatment. ATR-IR spectra demonstrated differences in chemical bounds pre- versus post-treatment. FN3K and FAOD can achieve deglycation and the effects are most optimal when combined in one treatment.
Collapse
Affiliation(s)
- Ignace De Decker
- Burn Center, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
- Department of Plastic Surgery, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Margo Notebaert
- Department of Diagnostic Sciences, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Marijn M Speeckaert
- Department of Nephrology, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Karel E Y Claes
- Burn Center, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
- Department of Plastic Surgery, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Phillip Blondeel
- Burn Center, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
- Department of Plastic Surgery, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Elisabeth Van Aken
- Department of Head and Skin, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Jo Van Dorpe
- Department of Pathology, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Filip De Somer
- Department of Cardiac Surgery, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Margaux Heintz
- Faculty of Medicine and Health Sciences, Ghent University, Sint-Pietersnieuwstraat 33, 9000 Ghent, Belgium
| | - Stan Monstrey
- Burn Center, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
- Department of Plastic Surgery, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| | - Joris R Delanghe
- Department of Diagnostic Sciences, Ghent University Hospital, C. Heymanslaan 10, 9000 Ghent, Belgium
| |
Collapse
|
4
|
Strath LJ, Sorge RE. Racial Differences in Pain, Nutrition, and Oxidative Stress. Pain Ther 2022; 11:37-56. [PMID: 35106711 PMCID: PMC8861224 DOI: 10.1007/s40122-022-00359-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 01/21/2022] [Indexed: 12/12/2022] Open
Abstract
Investigating the disproportionate rates of chronic pain and their related comorbidities between Black and non-Hispanic White (White) individuals is a growing area of interest, both in the healthcare community and in general society. Researchers have identified racial differences in chronic pain prevalence and severity, but still very little is known about the mechanisms underlying them. Current explanations for these differences have primarily focused on socioeconomic status and unequal healthcare between races as causal factors. Whereas these factors are informative, a racial gap still exists between Black and White individuals when these factors are controlled for. One potential cause of this racial gap in chronic pain is the differences in nutrition and dietary intake between groups. Certain foods play a key role in the inflammatory and oxidative stress pathways in the human body and could potentially influence the severity of the pain experience. Here, we review the previous literature on the surrounding topics and propose a potential mechanism to explain racial differences in the chronic pain population, based on established racial differences in diet and oxidative stress.
Collapse
Affiliation(s)
- Larissa J Strath
- Department of Psychology, The University of Alabama at Birmingham, 1300 University Blvd, Birmingham, AL, 35294, USA
| | - Robert E Sorge
- Department of Psychology, The University of Alabama at Birmingham, 1300 University Blvd, Birmingham, AL, 35294, USA.
| |
Collapse
|
5
|
A Potential Role for Fructosamine-3-Kinase in Cataract Treatment. Int J Mol Sci 2021; 22:ijms22083841. [PMID: 33917258 PMCID: PMC8068021 DOI: 10.3390/ijms22083841] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/01/2021] [Accepted: 04/02/2021] [Indexed: 11/17/2022] Open
Abstract
Cataracts are the major cause of blindness worldwide, largely resulting from aging and diabetes mellitus. Advanced glycation end products (AGEs) have been identified as major contributors in cataract formation because they alter lens protein structure and stability and induce covalent cross-linking, aggregation, and insolubilization of lens crystallins. We investigated the potential of the deglycating enzyme fructosamine-3-kinase (FN3K) in the disruption of AGEs in cataractous lenses. Macroscopic changes of equine lenses were evaluated after ex vivo intravitreal FN3K injection. The mechanical properties of an equine lens pair were evaluated after treatment with saline and FN3K. AGE-type autofluorescence (AF) was measured to assess the time-dependent effects of FN3K on glycolaldehyde-induced AGE-modified porcine lens fragments and to evaluate its actions on intact lenses after in vivo intravitreal FN3K injection of murine eyes. A potential immune response after injection was evaluated by analysis of IL-2, TNFα, and IFNγ using an ELISA kit. Dose- and time-dependent AF kinetics were analyzed on pooled human lens fragments. Furthermore, AF measurements and a time-lapse of macroscopic changes were performed on intact cataractous human eye lenses after incubation with an FN3K solution. At last, AF measurements were performed on cataractous human eyes after crossover topical treatment with either saline- or FN3K-containing drops. While the lenses of the equine FN3K-treated eyes appeared to be clear, the saline-treated lenses had a yellowish-brown color. Following FN3K treatment, color restoration could be observed within 30 min. The extension rate of the equine FN3K-treated lens was more than twice the extension rate of the saline-treated lens. FN3K treatment induced significant time-dependent decreases in AGE-related AF values in the AGE-modified porcine lens fragments. Furthermore, in vivo intravitreal FN3K injection of murine eyes significantly reduced AF values of the lenses. Treatment did not provoke a systemic immune response in mice. AF kinetics of FN3K-treated cataractous human lens suspensions revealed dose- and time-dependent decreases. Incubation of cataractous human eye lenses with FN3K resulted in a macroscopic lighter color of the cortex and a decrease in AF values. At last, crossover topical treatment of intact human eyes revealed a decrease in AF values during FN3K treatment, while showing no notable changes with saline. Our study suggests, for the first time, a potential additional role of FN3K as an alternative treatment for AGE-related cataracts.
Collapse
|
6
|
Dietary Interventions for Treatment of Chronic Pain: Oxidative Stress and Inflammation. Pain Ther 2020; 9:487-498. [PMID: 33085012 PMCID: PMC7648781 DOI: 10.1007/s40122-020-00200-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/22/2020] [Indexed: 12/20/2022] Open
Abstract
Chronic pain is highly prevalent in the United States, impacting 28.4% of the adult population, or 69.6 million people, as of 2016. Chronic pain is often associated with anxiety, depression, and restrictions in mobility and daily activities, substantially reducing quality of life. Analgesics, especially opioids, are one of the primary pharmaceutical treatment methods for chronic pain. However, prescription opioid misuse and abuse has become increasingly prevalent and concerning, prompting the need for research into alternative treatment methods which avoid the side effects of traditional treatments. Chronic pain is, in part, thought to be the result of oxidative stress and inflammation, and clinical research has indicated links between these conditions and diet. Thus, dietary interventions are a particularly promising therapeutic treatment for chronic pain, with numerous studies suggesting that diet has a noticeable effect on pain as far down as the cellular level. In this review article, data from a number of clinical trials assessing the effect of three diets—antioxidant-rich, low-carbohydrate, and Mediterranean—on oxidative stress and inflammation is compiled and discussed in the context of chronic pain. Clinical data suggests that low-carbohydrate diets and Mediterranean diets both are especially promising dietary interventions.
Collapse
|
7
|
De Bruyne S, Van den Broecke C, Vrielinck H, Khelifi S, De Wever O, Bracke K, Huizing M, Boston N, Himpe J, Speeckaert M, Vral A, Van Dorpe J, Van Aken E, Delanghe JR. Fructosamine-3-Kinase as a Potential Treatment Option for Age-Related Macular Degeneration. J Clin Med 2020; 9:jcm9092869. [PMID: 32899850 PMCID: PMC7565857 DOI: 10.3390/jcm9092869] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 08/22/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
Age-related macular degeneration is the leading cause of blindness in the developed world. Since advanced glycation end products (AGEs) are implicated in the pathogenesis of AMD through various lines of evidence, we investigated the potential of fructosamine-3-kinase (FN3K) in the disruption of retinal AGEs, drusenoid material and drusenoid lesions in patients with AMD. AGE-type autofluorescence was measured to evaluate the effects of FN3K on glycolaldehyde-induced AGE-modified neural porcine retinas and unmodified human neural retinas. Eye pairs from cigarette-smoke- and air-exposed mice were treated and evaluated histologically. Automated optical image analysis of human tissue sections was performed to compare control- and FN3K-treated drusen and near-infrared (NIR) microspectroscopy was performed to examine biochemical differences. Optical coherence tomography (OCT) was used to evaluate the effect of FN3K on drusenoid deposits after treatment of post-mortem human eyes. FN3K treatment provoked a significant decrease (41%) of AGE-related autofluorescence in the AGE-modified porcine retinas. Furthermore, treatment of human neural retinas resulted in significant decreases of autofluorescence (−24%). FN3K-treated murine eyes showed less drusenoid material. Pairwise comparison of drusen on tissue sections revealed significant changes in color intensity after FN3K treatment. NIR microspectroscopy uncovered clear spectral differences in drusenoid material (Bruch’s membrane) and drusen after FN3K treatment. Ex vivo treatment strongly reduced size of subretinal drusenoid lesions on OCT imaging (up to 83%). In conclusion, our study demonstrated for the first time a potential role of FN3K in the disruption of AGE-related retinal autofluorescence, drusenoid material and drusenoid lesions in patients with AMD.
Collapse
Affiliation(s)
- Sander De Bruyne
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
| | | | - Henk Vrielinck
- Department of Solid State Sciences, Ghent University, 9000 Ghent, Belgium; (H.V.); (S.K.)
| | - Samira Khelifi
- Department of Solid State Sciences, Ghent University, 9000 Ghent, Belgium; (H.V.); (S.K.)
| | - Olivier De Wever
- Department of Human Structure and Repair, Ghent University, 9000 Ghent, Belgium; (O.D.W.); (A.V.)
| | - Ken Bracke
- Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium; (K.B.); (M.S.)
| | - Manon Huizing
- Biobank, Antwerp University Hospital, 2650 Antwerp, Belgium; (M.H.); (N.B.)
| | - Nezahat Boston
- Biobank, Antwerp University Hospital, 2650 Antwerp, Belgium; (M.H.); (N.B.)
| | - Jonas Himpe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
| | - Marijn Speeckaert
- Department of Internal Medicine and Pediatrics, Ghent University, 9000 Ghent, Belgium; (K.B.); (M.S.)
- Research Foundation Flanders, 1000 Brussels, Belgium
| | - Anne Vral
- Department of Human Structure and Repair, Ghent University, 9000 Ghent, Belgium; (O.D.W.); (A.V.)
| | - Jo Van Dorpe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
- Department of Pathology, Ghent University Hospital, 9000 Ghent, Belgium;
| | - Elisabeth Van Aken
- Department of Head and Skin, Ghent University, 9000 Ghent, Belgium
- Correspondence: (E.V.A.); (J.R.D.)
| | - Joris R. Delanghe
- Department of Diagnostic Sciences, Ghent University, 9000 Ghent, Belgium; (S.D.B.); (J.H.); (J.V.D.)
- Correspondence: (E.V.A.); (J.R.D.)
| |
Collapse
|
8
|
Shrestha S, Katiyar S, Sanz-Rodriguez CE, Kemppinen NR, Kim HW, Kadirvelraj R, Panagos C, Keyhaninejad N, Colonna M, Chopra P, Byrne DP, Boons GJ, van der Knaap E, Eyers PA, Edison AS, Wood ZA, Kannan N. A redox-active switch in fructosamine-3-kinases expands the regulatory repertoire of the protein kinase superfamily. Sci Signal 2020; 13:eaax6313. [PMID: 32636308 PMCID: PMC8455029 DOI: 10.1126/scisignal.aax6313] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aberrant regulation of metabolic kinases by altered redox homeostasis substantially contributes to aging and various diseases, such as diabetes. We found that the catalytic activity of a conserved family of fructosamine-3-kinases (FN3Ks), which are evolutionarily related to eukaryotic protein kinases, is regulated by redox-sensitive cysteine residues in the kinase domain. The crystal structure of the FN3K homolog from Arabidopsis thaliana revealed that it forms an unexpected strand-exchange dimer in which the ATP-binding P-loop and adjoining β strands are swapped between two chains in the dimer. This dimeric configuration is characterized by strained interchain disulfide bonds that stabilize the P-loop in an extended conformation. Mutational analysis and solution studies confirmed that the strained disulfides function as redox "switches" to reversibly regulate the activity and dimerization of FN3K. Human FN3K, which contains an equivalent P-loop Cys, was also redox sensitive, whereas ancestral bacterial FN3K homologs, which lack a P-loop Cys, were not. Furthermore, CRISPR-mediated knockout of FN3K in human liver cancer cells altered the abundance of redox metabolites, including an increase in glutathione. We propose that redox regulation evolved in FN3K homologs in response to changing cellular redox conditions. Our findings provide insights into the origin and evolution of redox regulation in the protein kinase superfamily and may open new avenues for targeting human FN3K in diabetic complications.
Collapse
Affiliation(s)
- Safal Shrestha
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Samiksha Katiyar
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Carlos E Sanz-Rodriguez
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Nolan R Kemppinen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Hyun W Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Renuka Kadirvelraj
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Charalampos Panagos
- Complex Carbohydrate Research Center (CCRC), University of Georgia, Athens, GA 30602, USA
| | - Neda Keyhaninejad
- Center for Applied Genetic Technologies (CAGT), University of Georgia, Athens, GA 30602, USA
| | - Maxwell Colonna
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Complex Carbohydrate Research Center (CCRC), University of Georgia, Athens, GA 30602, USA
| | - Pradeep Chopra
- Complex Carbohydrate Research Center (CCRC), University of Georgia, Athens, GA 30602, USA
| | - Dominic P Byrne
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Geert J Boons
- Complex Carbohydrate Research Center (CCRC), University of Georgia, Athens, GA 30602, USA
- Department of Chemical Biology and Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, and Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CG Utrecht, Netherlands
| | - Esther van der Knaap
- Center for Applied Genetic Technologies (CAGT), University of Georgia, Athens, GA 30602, USA
- Department of Horticulture, University of Georgia, Athens, GA 30602, USA
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA 30602, USA
| | - Patrick A Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Arthur S Edison
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
- Complex Carbohydrate Research Center (CCRC), University of Georgia, Athens, GA 30602, USA
| | - Zachary A Wood
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA.
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
9
|
Sartore G, Ragazzi E, Burlina S, Paleari R, Chilelli NC, Mosca A, Avemaria F, Lapolla A. Role of fructosamine-3-kinase in protecting against the onset of microvascular and macrovascular complications in patients with T2DM. BMJ Open Diabetes Res Care 2020; 8:8/1/e001256. [PMID: 32467223 PMCID: PMC7259852 DOI: 10.1136/bmjdrc-2020-001256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/02/2020] [Accepted: 04/30/2020] [Indexed: 01/21/2023] Open
Abstract
INTRODUCTION Microangiopathic and macroangiopathic complications are the main cause of morbidity and mortality in the diabetic population. Numerous publications have highlighted the role of glycation in the onset of complications of diabetes. In this context, the detection of fructosamine-3-kinase (FN3K)-an enzyme capable of counteracting the effect of hyperglycemia by intervening in protein glycation-has attracted great interest. Several studies have linked FN3K genetic variability to its enzymatic activity and glycated hemoglobin (HbA1c) levels. Here, we investigated the role of FN3K polymorphisms in the development of microvascular and macrovascular complications of diabetes. RESEARCH DESIGN AND METHODS The anthropometric and biochemical parameters, and any medical history of microangiopathic and macroangiopathic complications, were documented in a sample of 80 subjects with type 2 diabetes. All subjects were screened for FN3K gene and analyzed for the combination of three polymorphisms known to be associated with its enzymatic activity (rs3859206 and rs2256339 in the promoter region and rs1056534 in exon 6). RESULTS The combination of allelic variants of FN3K polymorphisms resulted in 13 distinct genotypic variants within the cohort. Comparison between genotypes showed no significant differences in terms of demographic, anthropometric and biochemical parameters, risk markers and long-term complications, except for a higher age and vitamin E levels associated with the genotype presenting GG at position -385, TT at position -232, and CC at c.900 A. Evaluating the microangiopathic and macroangiopathic complications as a whole, we found that they appeared significantly less present in this genotype compared with all other genotypes (p=0.0306). CONCLUSIONS The group of patients carrying the favorable allele for the three polymorphisms of the FN3K gene revealed less severe microangiopathy and macroangiopathy, suggesting a protective role of this genotype against the onset of the complications of diabetes.
Collapse
Affiliation(s)
- Giovanni Sartore
- Department of Medicine (DIMED), University of Padova School of Medicine and Surgery, Padova, Italy
| | - Eugenio Ragazzi
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova School of Medicine and Surgery, Padova, Italy
| | - Silvia Burlina
- Department of Medicine (DIMED), University of Padova School of Medicine and Surgery, Padova, Italy
| | - Renata Paleari
- Department of Pathophysiology and Transplantation, University of Milan, Milano, Italy
- Istituto di Tecnologie Biomediche, Consiglio Nazionale delle Ricerche (ITB-CNR), Milan, Italy
| | - Nino Cristiano Chilelli
- Department of Medicine (DIMED), University of Padova School of Medicine and Surgery, Padova, Italy
| | - Andrea Mosca
- Department of Pathophysiology and Transplantation, University of Milan, Milano, Italy
- Istituto di Tecnologie Biomediche, Consiglio Nazionale delle Ricerche (ITB-CNR), Milan, Italy
| | - Francesca Avemaria
- Department of Pathophysiology and Transplantation, University of Milan, Milano, Italy
| | - Annunziata Lapolla
- Department of Medicine (DIMED), University of Padova School of Medicine and Surgery, Padova, Italy
| |
Collapse
|
10
|
Strath LJ, Jones CD, Philip George A, Lukens SL, Morrison SA, Soleymani T, Locher JL, Gower BA, Sorge RE. The Effect of Low-Carbohydrate and Low-Fat Diets on Pain in Individuals with Knee Osteoarthritis. PAIN MEDICINE (MALDEN, MASS.) 2020; 21:150-160. [PMID: 30865775 PMCID: PMC7999621 DOI: 10.1093/pm/pnz022] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Osteoarthritis is the most prominent form of arthritis, affecting approximately 15% of the population in the United States. Knee osteoarthritis (KOA) has become one of the leading causes of disability in older adults. Besides knee replacement, there are no curative treatments for KOA, so persistent pain is commonly treated with opioids, acetaminophen, and nonsteroidal anti-inflammatory drugs. However, these drugs have many unpleasant side effects, so there is a need for alternative forms of pain management. We sought to test the efficacy of a dietary intervention to reduce KOA. DESIGN A randomized controlled pilot study to test the efficacy of two dietary interventions. SUBJECTS Adults 65-75 years of age with KOA. METHODS Participants were asked to follow one of two dietary interventions (low-carbohydrate [LCD], low-fat [LFD]) or continue to eat as usual (control [CTRL]) over 12 weeks. Functional pain, self-reported pain, quality of life, and depression were assessed every three weeks. Serum from before and after the diet intervention was analyzed for oxidative stress. RESULTS Over a period of 12 weeks, the LCD reduced pain intensity and unpleasantness in some functional pain tasks, as well as self-reported pain, compared with the LFD and CTRL. The LCD also significantly reduced oxidative stress and the adipokine leptin compared with the LFD and CTRL. Reduction in oxidative stress was related to reduced functional pain. CONCLUSIONS We present evidence suggesting that oxidative stress may be related to functional pain, and lowering it through our LCD intervention could provide relief from pain and be an opioid alternative.
Collapse
Affiliation(s)
- Larissa J Strath
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Catherine D Jones
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Alan Philip George
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Shannon L Lukens
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Shannon A Morrison
- School of Nursing, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Taraneh Soleymani
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Julie L Locher
- Division of Gerontology, Geriatrics and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Barbara A Gower
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Robert E Sorge
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
11
|
Hause F, Schlote D, Simm A, Hoffmann K, Santos AN. Accumulation of glycated proteins suggesting premature ageing in lamin B receptor deficient mice. Biogerontology 2018; 19:95-100. [PMID: 29081010 DOI: 10.1007/s10522-017-9733-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/19/2017] [Indexed: 01/01/2023]
Abstract
Accumulation of advanced glycation end products (AGEs) is accompanied by increased free radical activity which contributes to ageing and the development or worsening of degenerative diseases. Apart from other physiological factors, AGEs are also an important biomarker for premature ageing. Here we report protein modifications (glycation) in a mouse model of lamin B receptor deficient ic J /ic J mice displaying skin defects similar to those of classical progeria. Therefore, we analysed AGE-modifications in protein extracts from various tissues of ic J /ic J mice. Our results demonstrated that pentosidine as well as argpyrimidine were increased in ic J /ic J mice indicating a modification specific increase in biomarkers of ageing, especially derived from glycolysis dependent methylglyoxal. Furthermore, the expression of AGE-preventing enzymes (Glo1, Fn3k) differed between ic J /ic J and control mice. The results indicate that not only lamin A but also the lamin B receptor may be involved in ageing processes.
Collapse
Affiliation(s)
- Frank Hause
- Institute for Human Genetics, Martin Luther University of Halle-Wittenberg, 06112, Halle, Germany
| | - Dietmar Schlote
- Institute for Human Genetics, Martin Luther University of Halle-Wittenberg, 06112, Halle, Germany.
| | - Andreas Simm
- Clinic for Cardiac und Thoracic Surgery, Martin Luther University of Halle-Wittenberg, 06097, Halle, Germany
| | - Katrin Hoffmann
- Institute for Human Genetics, Martin Luther University of Halle-Wittenberg, 06112, Halle, Germany
| | - Alexander Navarrete Santos
- Clinic for Cardiac und Thoracic Surgery, Martin Luther University of Halle-Wittenberg, 06097, Halle, Germany
| |
Collapse
|
12
|
Inaba SI, Yamaguchi-Goto M, Tanaka-Takanaka K, Yonesu K, Sakurai H, Kubota K, Izumi T. Enzymatic kinetics regarding reversible metabolism of CS-0777, a sphingosine 1-phosphate receptor modulator, via phosphorylation and dephosphorylation in humans. Xenobiotica 2017; 48:258-268. [PMID: 28287856 DOI: 10.1080/00498254.2017.1306150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
1. CS-0777, a candidate compound for autoimmune diseases, becomes phosphorylated active metabolite, M1, by fructosamine 3-kinase (FN3K), FN3K-related protein (FN3K-RP); and M1 is reverted back to CS-0777 by alkaline phosphatase (ALP) in the body. We performed enzyme kinetic analysis of phosphorylation of CS-0777 by FN3K, FN3K-RP, human erythrocytes and human platelets; and dephosphorylation of M1 by various ALP isozymes and human liver, kidney, lung and small intestine microsomes. 2. The Michaelis constants of human FN3K, FN3K-RP and erythrocytes for CS-0777 phosphorylation were in the range from 498 μM to 1060 μM. FN3K inhibitor, 1-deoxy-1-morpholinofructose, suppressed only about 20% of CS-0777 phosphorylation activity in human erythrocyte lysate. Immunodepletion of FN3K and FN3K-RP decreased M1 formation activity by about 25% and 50%, respectively, in human erythrocyte lysate. 3. The Michaelis constants of four human ALPs and microsomes were in the range from 10.9 μM to 32.1 μM. The ALP inhibitor, levamisole, suppressed over 50% of M1 dephosphorylation activity in liver, kidney and lung microsomes. 4. FN3K-RP is expected to take a prominent role in the phosphorylation of CS-0777 in human erythrocytes; dephosphorylation of M1 was observed in all ALPs and human tissue microsomes examined, with a similar affinity towards M1 among them.
Collapse
Affiliation(s)
- Shin-Ichi Inaba
- a Drug Metabolism & Pharmacokinetics Research Laboratories, Daiichi Sankyo Co. Ltd , Tokyo , Japan
| | - Maki Yamaguchi-Goto
- a Drug Metabolism & Pharmacokinetics Research Laboratories, Daiichi Sankyo Co. Ltd , Tokyo , Japan
| | - Kaoru Tanaka-Takanaka
- a Drug Metabolism & Pharmacokinetics Research Laboratories, Daiichi Sankyo Co. Ltd , Tokyo , Japan
| | - Kiyoaki Yonesu
- b Oncology Laboratories, Daiichi Sankyo Co. Ltd , Tokyo , Japan , and
| | - Hidetaka Sakurai
- c Discovery Science and Technology Department, Daiichi Sankyo RD Novare Co. Ltd , Tokyo , Japan
| | - Kazuishi Kubota
- c Discovery Science and Technology Department, Daiichi Sankyo RD Novare Co. Ltd , Tokyo , Japan
| | - Takashi Izumi
- a Drug Metabolism & Pharmacokinetics Research Laboratories, Daiichi Sankyo Co. Ltd , Tokyo , Japan
| |
Collapse
|
13
|
Mosca L, Penco S, Patrosso MC, Marocchi A, Lapolla A, Sartore G, Chilelli NC, Paleari R, Mosca A. Genetic variability of the fructosamine 3-kinase gene in diabetic patients. Clin Chem Lab Med 2011; 49:803-8. [PMID: 21288167 DOI: 10.1515/cclm.2011.133] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Nonenzymatic glycation appears to be an important factor in the pathogenesis of diabetic complications. Fructosamine 3-kinase (FN3K), initially identified in erythrocytes, appears to be responsible for the removal of fructosamine from proteins, suggesting a protective role in nonenzymatic glycation. Recently, genetic variants in the FN3K gene have been studied in diabetic patients. The aim of our study was the molecular characterization of the FN3K gene in a representative group of Italian patients with type 1 (T1DM) and 2 (T2DM) diabetes mellitus and in a cohort of healthy controls. METHODS Seventy diabetic subjects (35 type 1 and 35 type 2) with stable glycemic control and 33 healthy control subjects were evaluated using PCR and direct sequencing of the FN3K gene. Denaturing high performance liquid chromatography (DHPLC) was used in controls for screening for the presence of the genetic variants previously found in diabetic patients. RESULTS Seven different genetic variants were identified, five of them already reported and two new: the p.R187X and p.Y239C mutations identified in two females affected by T2DM. No significant association was found between certain polymorphisms and diabetes conditions. Preliminary haplotype studies are also reported. With respect to genotypes, we noted that some were not present in all the investigated cohort, and some were found related to higher glycated hemoglobin compared to others, although not at a significant level, probably because of the small number of subjects investigated. CONCLUSIONS In conclusion, this study identified two new mutations and additional variants within the FN3K gene. This is the first study on FN3K in Italy. Future work is needed to achieve a better understanding of the FN3K enzyme and its possible clinical utility in the management of diabetic patients.
Collapse
Affiliation(s)
- Lorena Mosca
- Laboratorio di Genetica Medica, Ospedale Niguarda Ca' Granda, Milano, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Van Schaftingen E, Collard F, Wiame E, Veiga-da-Cunha M. Enzymatic repair of Amadori products. Amino Acids 2010; 42:1143-50. [PMID: 20967558 DOI: 10.1007/s00726-010-0780-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 08/22/2010] [Indexed: 11/25/2022]
Abstract
Protein deglycation, a new form of protein repair, involves several enzymes. Fructosamine-3-kinase (FN3K), an enzyme found in mammals and birds, phosphorylates fructosamines on the third carbon of their sugar moiety, making them unstable and causing them to detach from proteins. This enzyme acts particularly well on fructose-epsilon-lysine, both in free form and in the accessible regions of proteins. Mice deficient in FN3K accumulate protein-bound fructosamines and free fructoselysine, indicating that the deglycation mechanism initiated by FN3K is operative in vivo. Mammals and birds also have an enzyme designated 'FN3K-related protein' (FN3KRP), which shares ≈ 65% sequence identity with FN3K. Unlike FN3K, FN3KRP does not phosphorylate fructosamines, but acts on ribulosamines and erythrulosamines. As with FN3K, the third carbon is phosphorylated and this leads to destabilization of the ketoamines. Experiments with intact erythrocytes indicate that FN3KRP is also a protein-repair enzyme. Its physiological substrates are most likely formed from ribose 5-phosphate and erythrose 4-phosphate, which give rise to ketoamine 5- or 4-phosphates. The latter are dephosphorylated by 'low-molecular-weight protein-tyrosine-phosphatase-A' (LMW-PTP-A) before FN3KRP transfers a phosphate on the third carbon. The specificity of FN3K homologues present in plants and bacteria is similar to that of mammalian FN3KRP, suggesting that deglycation of ribulosamines and/or erythrulosamines is an ancient mechanism. Mammalian cells contain also a phosphatase acting on fructosamine 6-phosphates, which result from the reaction of proteins with glucose 6-phosphate.
Collapse
Affiliation(s)
- Emile Van Schaftingen
- de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, B-1200, Brussels, Belgium.
| | | | | | | |
Collapse
|
15
|
|
16
|
Caruso MG, Notarnicola M, Altomare DF, Misciagna G. Gene expression of fructosamine 3 kinase in patients with colorectal cancer. Oncology 2008; 73:72-5. [PMID: 18334852 DOI: 10.1159/000120631] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 09/12/2007] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Spontaneous non-enzymatic reaction of protein amino groups with glucose and other reducing sugars, known as glycation or Maillard reaction, has long been considered irreversible and inevitably followed by slow conversion of fructosamines and advanced glycation end products. Instead, recent identification of fructosamine 3 kinase (FN3K) has unveiled that fructosamines can be physiologically repaired, so that the FN3K enzyme could be considered a new form of protein repair. METHODS Thirty-one consecutive patients with colorectal cancer were enrolled in the study. FN3K gene expression was determined using quantitative RT-PCR. RESULTS The mean level of FN3K gene expression was significantly lower in cancer tissue than in the corresponding normal colorectal mucosa, and FN3K gene was under-expressed most particularly in the tumours located on the left side of the colon. CONCLUSIONS Low mRNA levels of this enzyme in colon cancer tissue with respect to normal surrounding mucosa suggests that neoplastic cells have lost a protective enzymatic system. Reduced FN3K gene expression may be important in the pathogenesis and progression of colorectal cancer.
Collapse
Affiliation(s)
- Maria Gabriella Caruso
- Laboratory of Biochemistry, National Institute for Digestive Diseases S. de Bellis, Castellana Grotte, Italy
| | | | | | | |
Collapse
|
17
|
Szwergold B, Manevich Y, Payne L, Loomes K. Fructosamine-3-kinase-related-protein phosphorylates glucitolamines on the C-4 hydroxyl: Novel substrate specificity of an enigmatic enzyme. Biochem Biophys Res Commun 2007; 361:870-5. [PMID: 17686456 DOI: 10.1016/j.bbrc.2007.07.127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Accepted: 07/12/2007] [Indexed: 11/21/2022]
Abstract
Fructosamine-3-kinase (FN3K) phosphorylates fructosamines to fructosamine-3-phosphates. Recent data from FN3K-knockout mouse indicate that this phosphorylation results in deglycation of proteins modified by non-enzymatic glycation process. A homolog of FN3K, the FN3K-related-protein (FN3KRP) displays 65% amino acid sequence identity with FN3K and is highly conserved in evolution. However, FN3KRP does not phosphorylate substrates of FN3K such as fructoselysine and its physiological function remains unknown. We observed that human erythrocytes that contain both enzymes phosphorylate N-methylglucamine (meglumine) to two products. One of these is meglumine-3-phosphate (Meg3P), an activity consistent with the known substrate specificity of FN3K. Here, we identify the second product as meglumine-4-phosphate (Meg4P) and show that it is produced specifically by FN3KRP. While it is unlikely that meglumine is the physiological target of FN3KRP, this novel specificity, along with FN3KRPs known phosphorylation of some ketosamines on the C-3 hydroxyl may prove useful in identifying the physiological substrates of this kinase.
Collapse
Affiliation(s)
- Benjamin Szwergold
- Dartmouth Medical School, Remsen 311-314, HB 7515, Hanover, NH 03755, USA.
| | | | | | | |
Collapse
|
18
|
Abstract
Glycation is a major cause of spontaneous damage to proteins in physiological systems. This is exacerbated in diabetes as a consequence of the increase in glucose and other saccharides derivatives in plasma and at the sites of vascular complications. Protein damage by the formation of early glycation adducts is limited to lysine side chain and N-terminal amino groups whereas later stage adducts, advanced glycation endproducts (AGEs), modify these and also arginine and cysteine residues. Metabolic dysfunction in vascular cells leads to the increased formation of methylglyoxal which adds disproportionately to the glycation damage in hyperglycaemia. AGE-modified proteins undergo cellular proteolysis leading to the formation and urinary excretion of glycation free adducts. AGEs may potentiate the development of diabetic complications by activation of cell responses by AGE-modified proteins interacting with specific cell surface receptors, activation of cell responses by AGE free adducts, impairment of protein-protein and enzyme-substrate interactions by AGE residue formation, and increasing resistance to proteolysis of extracellular matrix proteins. The formation of AGEs is suppressed by intensive glycaemic control, and may in future be suppressed by thiamine and pyridoxamine supplementation, and several other pharmacological agents. Increasing expression of enzymes of the enzymatic defence against glycation provides a novel and potentially effective future therapeutic strategy to suppress protein glycation.
Collapse
Affiliation(s)
- N Ahmed
- Department of Biological Sciences, University of Essex, Central Campus, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK
| | | |
Collapse
|
19
|
Szwergold BS. Fructosamine-6-phosphates are deglycated by phosphorylation to fructosamine-3,6-bisphosphates catalyzed by fructosamine-3-kinase (FN3K) and/or fructosamine-3-kinase-related-protein (FN3KRP). Med Hypotheses 2006; 68:37-45. [PMID: 16920277 DOI: 10.1016/j.mehy.2006.06.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 06/19/2006] [Accepted: 06/21/2006] [Indexed: 11/30/2022]
Abstract
Nonenzymatic glycation of proteins and some phospholipids by glucose and other reducing sugars (a.k.a Maillard reaction) is an unavoidable result of the coexistence of these sugars and the affected macromolecules in living systems. The consequences of this process are deleterious both in the intracellular and extracellular environments as evidenced by the close association between increased nonenzymatic glycation and complications of diabetes. Because of these considerations, we have proposed that the intrinsic toxicity of glucose and other sugars is counteracted in vivo by active deglycation mechanisms including transglycation of Schiff's bases and FN3K-dependent breakdown of fructosamines. While this modified hypothesis is receiving increasing experimental support, several issues regarding glycation/deglycation remain unresolved. Two such important questions are In this paper we propose a resolution of both these quandaries by proposing that fructosamine-6-phosphates are deglycated by phosphorylation to fructosamine-3,6-bisphosphates catalyzed by FN3KRP and/or possibly FN3K. We provide some preliminary evidence in support of this hypothesis and outline experimental approaches for definitive tests of this hypothesis. The potential medical implications of this finding are not clear yet but, if correct, this observation is likely to have a major impact on our understanding of the very basic and hitherto unexplored aspect of glucose metabolism and chemistry in vivo. One can imagine that, at some point in the future, measurement of FN3K/FN3KRP activity may be of diagnostic value in assessing an individual's susceptibility to diabetic complications. Further down the road, one can also envision a gene therapeutic intervention to bolster FN3K/FN3KRP-based antiglycation defenses.
Collapse
Affiliation(s)
- Benjamin S Szwergold
- Department of Medicine, Dartmouth Medical School, Remsen 311-314, HB 7515, Hanover, NH 03755, USA.
| |
Collapse
|
20
|
Szwergold BS, Howell SK, Beisswenger PJ. Transglycation--a potential new mechanism for deglycation of Schiff's bases. Ann N Y Acad Sci 2005; 1043:845-64. [PMID: 16037312 DOI: 10.1196/annals.1333.097] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nonenzymatic glycation is believed to play a major role in the development of diabetic complications. Over the past several years we and others have shown that in cells this nonenzymatic process can be reversed by an ATP-dependent reaction catalyzed by fructosamine-3-kinase (FN3K) and possibly by its isozyme, fructosamine-3-kinase-related protein (FN3KRP). In this study we provide the first evidence that this FN3K-dependent deglycation, acting on the Amadori products, is complemented by another deglycation process operating on the very first product of nonenzymatic glycation, glucosylamines (Schiff's bases). We postulate that the first step in this Schiff's-base deglycation process occurs by transfer of the sugar moiety from macromolecule-bound glucosylamine to one of the low-molecular weight intracellular nucleophiles-in particular, glutathione. We term this reaction transglycation, and in this study we demonstrate that it occurs readily and spontaneously in vitro. We further propose that one of the spontaneously formed glucose-glutathione adduct(s) is subsequently removed from cells by a multidrug-resistance pump (MRP, MDR-protein, ATP-binding-cassette protein), metabolized, and excreted in urine. In support of this latter contention, we show that at least one transglycation product, glucose-cysteine, is found in human urine and that its concentrations are increased in diabetes.
Collapse
|