1
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Sas DJ, Mara K, Mehta RA, Seide BM, Banks CJ, Danese DS, McGregor TL, Lieske JC, Milliner DS. Natural history of urine and plasma oxalate in children with primary hyperoxaluria type 1. Pediatr Nephrol 2024; 39:141-148. [PMID: 37458799 PMCID: PMC11044200 DOI: 10.1007/s00467-023-06074-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/13/2023] [Accepted: 06/22/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND Primary hyperoxaluria type 1 (PH1) is a rare, severe genetic disease causing increased hepatic oxalate production resulting in urinary stone disease, nephrocalcinosis, and often progressive chronic kidney disease. Little is known about the natural history of urine and plasma oxalate values over time in children with PH1. METHODS For this retrospective observational study, we analyzed data from genetically confirmed PH1 patients enrolled in the Rare Kidney Stone Consortium PH Registry between 2003 and 2018 who had at least 2 measurements before age 18 years of urine oxalate-to-creatinine ratio (Uox:cr), 24-h urine oxalate excretion normalized to body surface area (24-h Uox), or plasma oxalate concentration (Pox). We compared values among 3 groups: homozygous G170R, heterozygous G170R, and non-G170R AGXT variants both before and after initiating pyridoxine (B6). RESULTS Of 403 patients with PH1 in the registry, 83 met the inclusion criteria. Uox:cr decreased rapidly over the first 5 years of life. Both before and after B6 initiation, patients with non-G170R had the highest Uox:cr, 24-h Uox, and Pox. Patients with heterozygous G170R had similar Uox:cr to homozygous G170R prior to B6. Patients with homozygous G170R had the lowest 24-h Uox and Uox:cr after B6. Urinary oxalate excretion and Pox tend to decrease over time during childhood. eGFR over time was not different among groups. CONCLUSIONS Children with PH1 under 5 years old have relatively higher urinary oxalate excretion which may put them at greater risk for nephrocalcinosis and kidney failure than older PH1 patients. Those with homozygous G170R variants may have milder disease. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- David J Sas
- Division of Pediatric Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.
| | - Kristin Mara
- Division of Clinical Trials and Biostatistics, Mayo Clinic, Rochester, MN, USA
| | - Ramila A Mehta
- Division of Clinical Trials and Biostatistics, Mayo Clinic, Rochester, MN, USA
| | - Barbara M Seide
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Carly J Banks
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | | | - John C Lieske
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Dawn S Milliner
- Division of Pediatric Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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2
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Wannous H. Primary hyperoxaluria type 1 in children: clinical and laboratory manifestations and outcome. Pediatr Nephrol 2023:10.1007/s00467-023-05917-x. [PMID: 36917293 DOI: 10.1007/s00467-023-05917-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 03/16/2023]
Abstract
BACKGROUND Primary hyperoxaluria (PH) results from genetic mutations in different genes of glyoxylate metabolism, which cause significant increases in production of oxalate by the liver. This study aimed to report clinical and laboratory manifestations and outcome of PH type 1 in children in our center. METHODS A single-center observational cohort study was conducted at Children's University Hospital in Damascus, and included all patients admitted from 2018 to 2020, with a diagnosis of hyperoxaluria (urinary oxalate excretion > 45 mg/1.73 m2/day, or > 0.5 mmol/1.73 m2/day). PH type 1 (PH1) diagnosis was established by identification of biallelic pathogenic variants (compound heterozygous or homozygous mutations) in AGXT gene on molecular genetic testing. RESULTS The study included 100 patients with hyperoxaluria, with slight male dominance (57%), and median age 1.75 years (range, 1 month-14 years). Initial complaint was urolithiasis or nephrocalcinosis in 47%, kidney failure manifestations in 29%, and recurrent urinary tract infection in 24%. AGXT mutations were detected in 40 patients, and 72.5% of PH1 patients had kidney failure at presentation. Neither gender, age nor urinary oxalate excretion in 24 h had statistical significance in distinguishing PH1 from other forms of hyperoxaluria (P-Value > 0.05). Parental consanguinity, family history of kidney stones, bilateral nephrocalcinosis, presence of oxalate crystals in random urine sample, kidney failure and mortality were statistically significantly higher in PH1 (P-values < 0.05). Mortality was 32.5% among PH1 patients, with 4 PH1 patients (10%) on hemodialysis awaiting combined liver-kidney transplantation. CONCLUSION PH1 is still a grave disease with wide variety of clinical presentations which frequent results in delays in diagnosis, thus kidney failure is still a common presentation. In Syria, we face many challenges in diagnosis of PH, especially PH2 and PH3, and in management, with hopes that diagnosis tools and modern therapies will become available in our country. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Hala Wannous
- Faculty Member of Pediatric Nephrology in Faculty of Medicine, Damascus University, Damascus, Syria. .,Pediatric Nephrology, Hemodialysis, and Kidney Transplantation Department at Children's University Hospital, Damascus University, Damascus, Syria.
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3
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Gatticchi L, Grottelli S, Ambrosini G, Pampalone G, Gualtieri O, Dando I, Bellezza I, Cellini B. CRISPR/Cas9-mediated knock-out of AGXT1 in HepG2 cells as a new in vitro model of Primary Hyperoxaluria Type 1. Biochimie 2022; 202:110-122. [PMID: 35964771 DOI: 10.1016/j.biochi.2022.08.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 08/04/2022] [Accepted: 08/06/2022] [Indexed: 11/02/2022]
Abstract
AGXT1 encodes alanine:glyoxylate aminotransferase 1 (AGT1), a liver peroxisomal pyridoxal 5'-phosphate dependent-enzyme whose deficit causes Primary Hyperoxaluria Type 1 (PH1). PH1 is a rare disease characterized by overproduction of oxalate, first leading to kidney stones formation, and possibly evolving to life-threatening systemic oxalosis. A minority of PH1 patients is responsive to pyridoxine, while the option for non-responders is liver-kidney transplantation. Therefore, huge efforts are currently focused on the identification of new therapies, including the promising approaches based on RNA silencing recently approved. Many PH1-associated mutations are missense and lead to a variety of kinetic and/or folding defects on AGT1. In this context, the availability of a reliable in vitro disease model would be essential to better understand the phenotype of known or newly-identified pathogenic variants as well as to test novel drug candidates. Here, we took advantage of the CRISPR/Cas9 technology to specifically knock-out AGXT1 in HepG2 cells, a hepatoma-derived cell model exhibiting a conserved glyoxylate metabolism. AGXT1-KO HepG2 displayed null AGT1 expression and significantly reduced transaminase activity leading to an enhanced secretion of oxalate upon glycolate challenge. Known pathogenic AGT1 variants expressed in AGXT1-KO HepG2 cells showed alteration in both protein levels and specific transaminase activity, as well as a partial mitochondrial mistargeting when associated with a common polymorphism. Notably, pyridoxine treatment was able to partially rescue activity and localization of clinically-responsive variants. Overall, our data validate AGXT1-KO HepG2 cells as a novel cellular model to investigate PH1 pathophysiology, and as a platform for drug discovery and development.
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Affiliation(s)
- Leonardo Gatticchi
- Department of Medicine and Surgery, Physiology and Biochemistry Section, University of Perugia, 06132, Perugia, Italy
| | - Silvia Grottelli
- Department of Medicine and Surgery, Physiology and Biochemistry Section, University of Perugia, 06132, Perugia, Italy
| | - Giulia Ambrosini
- Department of Neurosciences, Biomedicine and Movement Sciences, Biochemistry Section, University of Verona, 37134, Verona, Italy
| | - Gioena Pampalone
- Department of Medicine and Surgery, Physiology and Biochemistry Section, University of Perugia, 06132, Perugia, Italy
| | - Ottavia Gualtieri
- Department of Medicine and Surgery, Physiology and Biochemistry Section, University of Perugia, 06132, Perugia, Italy
| | - Ilaria Dando
- Department of Neurosciences, Biomedicine and Movement Sciences, Biochemistry Section, University of Verona, 37134, Verona, Italy
| | - Ilaria Bellezza
- Department of Medicine and Surgery, Physiology and Biochemistry Section, University of Perugia, 06132, Perugia, Italy
| | - Barbara Cellini
- Department of Medicine and Surgery, Physiology and Biochemistry Section, University of Perugia, 06132, Perugia, Italy.
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4
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Grottelli S, Annunziato G, Pampalone G, Pieroni M, Dindo M, Ferlenghi F, Costantino G, Cellini B. Identification of Human Alanine-Glyoxylate Aminotransferase Ligands as Pharmacological Chaperones for Variants Associated with Primary Hyperoxaluria Type 1. J Med Chem 2022; 65:9718-9734. [PMID: 35830169 PMCID: PMC9340776 DOI: 10.1021/acs.jmedchem.2c00142] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
![]()
Primary hyperoxaluria type I (PH1) is a rare kidney disease
due
to the deficit of alanine:glyoxylate aminotransferase (AGT), a pyridoxal-5′-phosphate-dependent
enzyme responsible for liver glyoxylate detoxification, which in turn
prevents oxalate formation and precipitation as kidney stones. Many
PH1-associated missense mutations cause AGT misfolding. Therefore,
the use of pharmacological chaperones (PCs), small molecules that
promote correct folding, represents a useful therapeutic option. To
identify ligands acting as PCs for AGT, we first performed a small
screening of commercially available compounds. We tested each molecule
by a dual approach aimed at defining the inhibition potency on purified
proteins and the chaperone activity in cells expressing a misfolded
variant associated with PH1. We then performed a chemical optimization
campaign and tested the resulting synthetic molecules using the same
approach. Overall, the results allowed us to identify a promising
hit compound for AGT and draw conclusions about the requirements for
optimal PC activity.
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Affiliation(s)
- Silvia Grottelli
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy
| | - Giannamaria Annunziato
- Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Gioena Pampalone
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy
| | - Marco Pieroni
- Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Mirco Dindo
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy
| | - Francesca Ferlenghi
- Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Gabriele Costantino
- Department of Food and Drug, University of Parma, Parco Area delle Scienze 27/A, 43124 Parma, Italy
| | - Barbara Cellini
- Department of Medicine and Surgery, University of Perugia, P.le L. Severi 1, 06132 Perugia, Italy
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5
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Dindo M, Pascarelli S, Chiasserini D, Grottelli S, Costantini C, Uechi G, Giardina G, Laurino P, Cellini B. Structural dynamics shape the fitness window of alanine:glyoxylate aminotransferase. Protein Sci 2022; 31:e4303. [PMID: 35481644 PMCID: PMC8996469 DOI: 10.1002/pro.4303] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 03/02/2022] [Accepted: 03/17/2022] [Indexed: 01/24/2023]
Abstract
The conformational landscape of a protein is constantly expanded by genetic variations that have a minimal impact on the function(s) while causing subtle effects on protein structure. The wider the conformational space sampled by these variants, the higher the probabilities to adapt to changes in environmental conditions. However, the probability that a single mutation may result in a pathogenic phenotype also increases. Here we present a paradigmatic example of how protein evolution balances structural stability and dynamics to maximize protein adaptability and preserve protein fitness. We took advantage of known genetic variations of human alanine:glyoxylate aminotransferase (AGT1), which is present as a common major allelic form (AGT‐Ma) and a minor polymorphic form (AGT‐Mi) expressed in 20% of Caucasian population. By integrating crystallographic studies and molecular dynamics simulations, we show that AGT‐Ma is endowed with structurally unstable (frustrated) regions, which become disordered in AGT‐Mi. An in‐depth biochemical characterization of variants from an anticonsensus library, encompassing the frustrated regions, correlates this plasticity to a fitness window defined by AGT‐Ma and AGT‐Mi. Finally, co‐immunoprecipitation analysis suggests that structural frustration in AGT1 could favor additional functions related to protein–protein interactions. These results expand our understanding of protein structural evolution by establishing that naturally occurring genetic variations tip the balance between stability and frustration to maximize the ensemble of conformations falling within a well‐defined fitness window, thus expanding the adaptability potential of the protein.
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Affiliation(s)
- Mirco Dindo
- Protein Engineering and Evolution Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | - Stefano Pascarelli
- Protein Engineering and Evolution Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | | | - Silvia Grottelli
- Department of Medicine and Surgery University of Perugia Perugia Italy
| | | | - Gen‐Ichiro Uechi
- Protein Engineering and Evolution Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | - Giorgio Giardina
- Department of Biochemical Sciences “A. Rossi Fanelli” Sapienza University of Rome Rome Italy
| | - Paola Laurino
- Protein Engineering and Evolution Unit Okinawa Institute of Science and Technology Graduate University Okinawa Japan
| | - Barbara Cellini
- Department of Medicine and Surgery University of Perugia Perugia Italy
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6
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Singh P, Harris PC, Sas DJ, Lieske JC. The genetics of kidney stone disease and nephrocalcinosis. Nat Rev Nephrol 2022; 18:224-240. [PMID: 34907378 DOI: 10.1038/s41581-021-00513-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 12/15/2022]
Abstract
Kidney stones (also known as urinary stones or nephrolithiasis) are highly prevalent, affecting approximately 10% of adults worldwide, and the incidence of stone disease is increasing. Kidney stone formation results from an imbalance of inhibitors and promoters of crystallization, and calcium-containing calculi account for over 80% of stones. In most patients, the underlying aetiology is thought to be multifactorial, with environmental, dietary, hormonal and genetic components. The advent of high-throughput sequencing techniques has enabled a monogenic cause of kidney stones to be identified in up to 30% of children and 10% of adults who form stones, with ~35 different genes implicated. In addition, genome-wide association studies have implicated a series of genes involved in renal tubular handling of lithogenic substrates and of inhibitors of crystallization in stone disease in the general population. Such findings will likely lead to the identification of additional treatment targets involving underlying enzymatic or protein defects, including but not limited to those that alter urinary biochemistry.
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Affiliation(s)
- Prince Singh
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Molecular Biology and Biochemistry, Mayo Clinic, Rochester, MN, USA
| | - David J Sas
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Pediatric Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - John C Lieske
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA. .,Division of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
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7
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Mandrile G, Pelle A, Sciannameo V, Benetti E, D'Alessandro MM, Emma F, Montini G, Peruzzi L, Petrarulo M, Romagnoli R, Vitale C, Cellini B, Giachino D. Primary hyperoxaluria in Italy: the past 30 years and the near future of a (not so) rare disease. J Nephrol 2022; 35:841-850. [PMID: 35218550 PMCID: PMC8995259 DOI: 10.1007/s40620-022-01258-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/12/2022] [Indexed: 11/29/2022]
Abstract
Background Primary hyperoxalurias (PHs) are rare autosomal recessive diseases of the glyoxylate metabolism; PH1 is caused by mutations in the AGXT gene, PH2 in GRHPR and PH3 in HOGA1. Methods Here we report the first large multi-center cohort of Italian PH patients collected over 30 years (1992–2020 median follow-up time 8.5 years). Complete genotype was available for 94/95 PH1 patients and for all PH2 (n = 3) and PH3 (n = 5) patients. Symptoms at onset were mainly nephrolithiasis (46.3%) and nephrocalcinosis (33.7%). Median age at onset of symptoms and diagnosis were 4.0 years and 9.9 years, respectively. Results Fifty-four patients (56.8%) were diagnosed after chronic kidney disease. Sixty-three patients (66.3%) developed end stage kidney disease (median age 14.0 years). Twenty-one patients had a kidney-only transplant and, among them, seven had a second kidney transplant combined with liver transplant. A combined kidney–liver transplant was carried out in 29 patients and a sequential kidney–liver transplant was performed in two. In five cases a preemptive liver transplant was performed. Those receiving a liver-only transplant tended to have lower kidney function at last follow-up. Conclusion Our study of PHs in Italy underlines a considerable diagnostic delay, which has only slightly decreased in recent years. Therefore, we suggest a more extensive use of both metabolic screening among patients with recurrent kidney stones and genotyping, including unambiguous assignment of minor/major allele status in order to promptly begin appropriate treatment. This will be fundamental in order to have access to the new therapies, which are mainly focused on substrate reduction for the oxalate-producing enzymes using RNA-interference. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s40620-022-01258-4.
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Affiliation(s)
- Giorgia Mandrile
- Genetic Unit and Thalassemia Center, San Luigi Gonzaga University Hospital, Regione Gonzole 10, 10043, Orbassano, TO, Italy.
| | - Alessandra Pelle
- Medical Genetics Unit, AOU Città della Salute e della Scienza, Turin, Italy
| | - Veronica Sciannameo
- Unit of Biostatistics, Epidemiology and Public Health, Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padova, Padua, Italy
| | - Elisa Benetti
- Pediatric Nephrology, Dialysis and Transplant Unit, Department of Women's and Children's Health, Padua University Hospital, Padua, Italy
| | - Maria Michela D'Alessandro
- Pediatric Nephrology Unit, Ospedale dei Bambini, A.R.N.A.S. Civico-G. Di Cristina, Benfratelli Palermo, PA, Italy
| | - Francesco Emma
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children's Hospital-IRCCS, Rome, Italy
| | - Giovanni Montini
- Pediatric Nephrology, Dialysis and Transplant Unit, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milano, Italy.,Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Licia Peruzzi
- Pediatric Nephrology Unit, "Regina Margherita Department of Children's Diseases", Città della Salute e della Scienza di Torino, Turin, Italy
| | - Michele Petrarulo
- Kidney Stone Laboratory-Chemical-Clinical Laboratory Unit, Azienda Ospedaliera Ordine Mauriziano di Torino, Turin, Italy
| | - Renato Romagnoli
- Liver Transplant Unit, General Surgery 2U, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, University of Turin, Turin, Italy
| | - Corrado Vitale
- Nephrology and Dialysis Unit, Azienda Ospedaliera Ordine Mauriziano di Torino, Turin, Italy
| | - Barbara Cellini
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Daniela Giachino
- Medical Genetic Unit, San Luigi Gonzaga University Hospital, Orbassano, TO, Italy.,Medical Genetics, Department Clinical and Biological Sciences, University of Torino, Turin, Italy
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8
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Forst AL, Reichold M, Kleta R, Warth R. Distinct Mitochondrial Pathologies Caused by Mutations of the Proximal Tubular Enzymes EHHADH and GATM. Front Physiol 2021; 12:715485. [PMID: 34349672 PMCID: PMC8326905 DOI: 10.3389/fphys.2021.715485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 06/28/2021] [Indexed: 12/18/2022] Open
Abstract
The mitochondria of the proximal tubule are essential for providing energy in this nephron segment, whose ATP generation is almost exclusively oxygen dependent. In addition, mitochondria are involved in a variety of metabolic processes and complex signaling networks. Proximal tubular mitochondrial dysfunction can therefore affect renal function in very different ways. Two autosomal dominantly inherited forms of renal Fanconi syndrome illustrate how multifaceted mitochondrial pathology can be: Mutation of EHHADH, an enzyme in fatty acid metabolism, results in decreased ATP synthesis and a consecutive transport defect. In contrast, mutations of GATM, an enzyme in the creatine biosynthetic pathway, leave ATP synthesis unaffected but do lead to mitochondrial protein aggregates, inflammasome activation, and renal fibrosis with progressive renal failure. In this review article, the distinct pathophysiological mechanisms of these two diseases are presented, which are examples of the spectrum of proximal tubular mitochondrial diseases.
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Affiliation(s)
- Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Markus Reichold
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Robert Kleta
- Centre for Nephrology, University College London, London, United Kingdom
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
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9
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Murad H, Alhalabi MB, Dabboul A, Alfakseh N, Nweder MS, Zghib Y, Wannous H. Molecular analysis of the AGXT gene in Syrian patients suspected with primary hyperoxaluria type 1. BMC Med Genomics 2021; 14:146. [PMID: 34082749 PMCID: PMC8176596 DOI: 10.1186/s12920-021-00996-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 05/27/2021] [Indexed: 11/10/2022] Open
Abstract
Background Characterization of the molecular basis of primary hyperoxaluria type 1 (PH-1) in Syria has been accomplished through the analysis of 90 unrelated chromosomes from 45 Syrians patients with PH-1 from different regions. Methods Alanine glyoxylate aminotransferase (AGXT) gene mutations have been analyzed by using molecular detection methods based on the direct DNA sequencing for all exons of the AGXT gene.
Results Seventeen pathogenic mutations were detected in our patients. Six mutations were novels. The three most frequent mutations were c.33_34insC (p.Lys12fs) in Exon 1, c.584 T < G; p.Met195Arg in exon 5 and c.1007 T > A (p.Val336Asp) in exon 10, with a frequency of 33.3%, 12.2%, and 11.1%, respectively. Conclusion DNA sequencing used in this study can offer a useful method to investigate the mutations in Syrian PH-1 patients, and could offer an accurate tool for prenatal diagnosis and genetic counseling.
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Affiliation(s)
- Hossam Murad
- Human Genetics Division, Molecular Biology and Biotechnology Department, Human Genetics Division, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria.
| | - Mohamad Baseel Alhalabi
- Human Genetics Division, Molecular Biology and Biotechnology Department, Human Genetics Division, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | - Amir Dabboul
- Human Genetics Division, Molecular Biology and Biotechnology Department, Human Genetics Division, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | - Nour Alfakseh
- Human Genetics Division, Molecular Biology and Biotechnology Department, Human Genetics Division, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | - Mohamad Sayah Nweder
- Human Genetics Division, Molecular Biology and Biotechnology Department, Human Genetics Division, Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | | | - Hala Wannous
- Chlidien's Hospital of Damascus, Damascus, Syria
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10
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Li Y, Zheng R, Xu G, Huang Y, Li Y, Li D, Geng H. Generation and characterization of a novel rat model of primary hyperoxaluria type 1 with a nonsense mutation in alanine-glyoxylate aminotransferase gene. Am J Physiol Renal Physiol 2021; 320:F475-F484. [PMID: 33491567 DOI: 10.1152/ajprenal.00514.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Primary hyperoxaluria type 1 (PH1) is a severe inherited disorder caused by a genetic defect in alanine-glyoxylate aminotransferase (AGXT), which results in recurrent urolithiasis and renal failure. Animal models that precisely reflect human PH1 phenotypes are lacking. We aimed to develop a novel PH1 rat model and study the mechanisms involved in PH1 deterioration. One cell stage Sprague-Dawley embryos were injected with the CRISPR/Cas9 system to introduce a Q84X mutation in Agxt. Liver tissues were harvested to determine Agxt expression. Urine oxalate, crystals, and electrolyte levels in AgxtQ84X and wild-type (WT) littermates were evaluated. Kidney tissues were used for Pizzolato staining and kidney injury evaluation. Data showed that Agxt mRNA and protein were absent in AgxtQ84X rats. At 4 and 24 wk, AgxtQ84X rats displayed 2.1- and 2.9-fold higher urinary oxalate levels, respectively, compared with WT littermates. As a result, calcium oxalate (CaOx) crystals in urine were revealed in all AgxtQ84X rats but in none of the WT rats. We also observed bladder stones in 36.4% of AgxtQ84X rats, of which 44.4% had renal CaOx deposition. Moreover, the elevated serum urea and creatinine levels indicated the impaired renal function in AgxtQ84X rats. Further investigation revealed significantly increased expression of inflammation-, necroptosis-, and fibrosis-related genes in the kidneys of AgxtQ84X rats with spontaneous renal CaOx deposition, indicating that these pathways are involved in PH1 deterioration. Collectively, these results suggest that this rat model has broad applicability in mechanistic studies and innovative therapeutics development for PH1 and other kidney stone diseases.NEW & NOTEWORTHY Primary hyperoxaluria type 1 is a severe inherited disorder that results in recurrent urolithiasis and renal failure. We generated an alanine-glyoxylate aminotransferase (Agxt)Q84X nonsense mutant rat model that displayed an early onset of hyperoxaluria, spontaneous renal CaOx precipitation, bladder stone, and kidney injuries. Our results suggest an interaction of renal CaOx crystals with the activation of inflammation-, fibrosis-, and necroptosis-related pathways. In all, the AgxtQ84X rat strain has broad applicability in mechanistic studies and the development of innovative therapeutics.
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Affiliation(s)
- Yueyan Li
- Department of Pediatric Urology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Children's Stone Treatment Center of National Health and Family Planning Commission of the People's Republic of China, Shanghai, People's Republic of China
| | - Rui Zheng
- Department of Pediatric Urology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Children's Stone Treatment Center of National Health and Family Planning Commission of the People's Republic of China, Shanghai, People's Republic of China
| | - Guofeng Xu
- Department of Pediatric Urology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Children's Stone Treatment Center of National Health and Family Planning Commission of the People's Republic of China, Shanghai, People's Republic of China
| | - Yunteng Huang
- Children's Stone Treatment Center of National Health and Family Planning Commission of the People's Republic of China, Shanghai, People's Republic of China.,Department of Urology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Yongmei Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Dali Li
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, People's Republic of China
| | - Hongquan Geng
- Department of Pediatric Urology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Children's Stone Treatment Center of National Health and Family Planning Commission of the People's Republic of China, Shanghai, People's Republic of China
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11
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The metabolic importance of the overlooked asparaginase II pathway. Anal Biochem 2020; 644:114084. [PMID: 33347861 DOI: 10.1016/j.ab.2020.114084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 11/23/2022]
Abstract
The asparaginase II pathway consists of an asparagine transaminase [l-asparagine + α-keto acid ⇆ α-ketosuccinamate + l-amino acid] coupled to ω-amidase [α-ketosuccinamate + H2O → oxaloacetate + NH4+]. The net reaction is: l-asparagine + α-keto acid + H2O → oxaloacetate + l-amino acid + NH4+. Thus, in the presence of a suitable α-keto acid substrate, the asparaginase II pathway generates anaplerotic oxaloacetate at the expense of readily dispensable asparagine. Several studies have shown that the asparaginase II pathway is important in photorespiration in plants. However, since its discovery in rat tissues in the 1950s, this pathway has been almost completely ignored as a conduit for asparagine metabolism in mammals. Several mammalian transaminases can catalyze transamination of asparagine, one of which - alanine-glyoxylate aminotransferase type 1 (AGT1) - is important in glyoxylate metabolism. Glyoxylate is a precursor of oxalate which, in the form of its calcium salt, is a major contributor to the formation of kidney stones. Thus, transamination of glyoxylate with asparagine may be physiologically important for the removal of potentially toxic glyoxylate. Asparaginase has been the mainstay treatment for certain childhood leukemias. We suggest that an inhibitor of ω-amidase may potentiate the therapeutic benefits of asparaginase treatment.
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12
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Just PA, Charawi S, Denis RGP, Savall M, Traore M, Foretz M, Bastu S, Magassa S, Senni N, Sohier P, Wursmer M, Vasseur-Cognet M, Schmitt A, Le Gall M, Leduc M, Guillonneau F, De Bandt JP, Mayeux P, Romagnolo B, Luquet S, Bossard P, Perret C. Lkb1 suppresses amino acid-driven gluconeogenesis in the liver. Nat Commun 2020; 11:6127. [PMID: 33257663 PMCID: PMC7705018 DOI: 10.1038/s41467-020-19490-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
Excessive glucose production by the liver is a key factor in the hyperglycemia observed in type 2 diabetes mellitus (T2DM). Here, we highlight a novel role of liver kinase B1 (Lkb1) in this regulation. We show that mice with a hepatocyte-specific deletion of Lkb1 have higher levels of hepatic amino acid catabolism, driving gluconeogenesis. This effect is observed during both fasting and the postprandial period, identifying Lkb1 as a critical suppressor of postprandial hepatic gluconeogenesis. Hepatic Lkb1 deletion is associated with major changes in whole-body metabolism, leading to a lower lean body mass and, in the longer term, sarcopenia and cachexia, as a consequence of the diversion of amino acids to liver metabolism at the expense of muscle. Using genetic, proteomic and pharmacological approaches, we identify the aminotransferases and specifically Agxt as effectors of the suppressor function of Lkb1 in amino acid-driven gluconeogenesis. Excessive glucose production by the liver contributes to poor blood glucose control in type 2 diabetes. Here the authors report that the liver kinase B1 (Lkb1) suppresses amino acid driven postprandial glucose production in the liver through the aminotransferase Agxt.
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Affiliation(s)
- Pierre-Alexandre Just
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.,APHP, Centre-Université de Paris, Paris, France
| | - Sara Charawi
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Raphaël G P Denis
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205, Paris, France
| | - Mathilde Savall
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Massiré Traore
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Marc Foretz
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Sultan Bastu
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | | | - Nadia Senni
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Pierre Sohier
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Maud Wursmer
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Mireille Vasseur-Cognet
- UMR IRD 242, UPEC, CNRS 7618, UPMC 113, INRA 1392, Sorbonne Universités Paris and Institut d'Ecologie et des Sciences de l'Environnement de Paris, Bondy, France
| | - Alain Schmitt
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.,Electron Miscroscopy Facility, Institut Cochin, F75014, Paris, France
| | - Morgane Le Gall
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.,3P5 proteom'IC Facility, Université de Paris, Institut Cochin, INSERM, CNRS, F-75014, Paris, France
| | - Marjorie Leduc
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.,3P5 proteom'IC Facility, Université de Paris, Institut Cochin, INSERM, CNRS, F-75014, Paris, France
| | - François Guillonneau
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.,3P5 proteom'IC Facility, Université de Paris, Institut Cochin, INSERM, CNRS, F-75014, Paris, France
| | | | - Patrick Mayeux
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.,3P5 proteom'IC Facility, Université de Paris, Institut Cochin, INSERM, CNRS, F-75014, Paris, France
| | - Béatrice Romagnolo
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Serge Luquet
- Unité de Biologie Fonctionnelle et Adaptative, Centre National la Recherche Scientifique, Unité Mixte de Recherche 8251, Université Paris Diderot, Sorbonne Paris Cité, 75205, Paris, France
| | - Pascale Bossard
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France
| | - Christine Perret
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014, Paris, France.
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13
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Dindo M, Mandrile G, Conter C, Montone R, Giachino D, Pelle A, Costantini C, Cellini B. The ILE56 mutation on different genetic backgrounds of alanine:glyoxylate aminotransferase: Clinical features and biochemical characterization. Mol Genet Metab 2020; 131:171-180. [PMID: 32792227 DOI: 10.1016/j.ymgme.2020.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 01/20/2023]
Abstract
Primary Hyperoxaluria type I (PH1) is a rare disease caused by mutations in the AGXT gene encoding alanine:glyoxylate aminotransferase (AGT), a liver enzyme involved in the detoxification of glyoxylate, the failure of which results in accumulation of oxalate and kidney stones formation. The role of protein misfolding in the AGT deficit caused by most PH1-causing mutations is increasingly being recognized. In addition, the genetic background in which a mutation occurs is emerging as a critical risk factor for disease onset and/or severity. Based on these premises, in this study we have analyzed the clinical, biochemical and cellular effects of the p.Ile56Asn mutation, recently described in a PH1 patient, as a function of the residue at position 11, a hot-spot for both polymorphic (p.Pro11Leu) and pathogenic (p.Pro11Arg) mutations. We have found that the p.Ile56Asn mutation induces a structural defect mostly related to the apo-form of AGT. The effects are more pronounced when the substitution of Ile56 is combined with the p.Pro11Leu and, at higher degree, the p.Pro11Arg mutation. As compared with the non-pathogenic forms, AGT variants display reduced expression and activity in mammalian cells. Vitamin B6, a currently approved treatment for PH1, can overcome the effects of the p.Ile56Asn mutation only when it is associated with Pro at position 11. Our results provide a first proof that the genetic background influences the effects of PH1-causing mutations and the responsiveness to treatment and suggest that molecular and cellular studies can integrate clinical data to identify the best therapeutic strategy for PH1 patients.
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Affiliation(s)
- Mirco Dindo
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Giorgia Mandrile
- Medical Genetics Unit, Department of Clinical and Biological Sciences, University of Torino, Orbassano (TO), Italy; Genetica e Thalassemia Unit, San Luigi University Hospital, Orbassano (TO), Italy
| | - Carolina Conter
- Department of Neurological, Biomedical, and Movement Sciences, University of Verona, Verona, Italy
| | - Rosa Montone
- Department of Neurological, Biomedical, and Movement Sciences, University of Verona, Verona, Italy
| | - Daniela Giachino
- Medical Genetics Unit, Department of Clinical and Biological Sciences, University of Torino, Orbassano (TO), Italy
| | - Alessandra Pelle
- Medical Genetics Unit, Department of Clinical and Biological Sciences, University of Torino, Orbassano (TO), Italy
| | - Claudio Costantini
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Barbara Cellini
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.
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14
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Dindo M, Conter C, Oppici E, Ceccarelli V, Marinucci L, Cellini B. Molecular basis of primary hyperoxaluria: clues to innovative treatments. Urolithiasis 2018; 47:67-78. [PMID: 30430197 DOI: 10.1007/s00240-018-1089-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 11/08/2018] [Indexed: 12/21/2022]
Abstract
Primary hyperoxalurias (PHs) are rare inherited disorders of liver glyoxylate metabolism, characterized by the abnormal production of endogenous oxalate, a metabolic end-product that is eliminated by urine. The main symptoms are related to the precipitation of calcium oxalate crystals in the urinary tract with progressive renal damage and, in the most severe form named Primary Hyperoxaluria Type I (PH1), to systemic oxalosis. The therapies currently available for PH are either poorly effective, because they address the symptoms and not the causes of the disease, or highly invasive. In the last years, advances in our understanding of the molecular bases of PH have paved the way for the development of new therapeutic strategies. They include (i) substrate-reduction therapies based on small-molecule inhibitors or the RNA interference technology, (ii) gene therapy, (iii) enzyme administration approaches, (iv) colonization with oxalate-degrading intestinal microorganisms, and, in PH1, (v) design of pharmacological chaperones. This paper reviews the basic principles of these new therapeutic strategies and what is currently known about their application to PH.
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Affiliation(s)
- Mirco Dindo
- Department of Experimental Medicine, University of Perugia, P.le Gambuli 1, 06132, Perugia, Italy
| | - Carolina Conter
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada le Grazie 8, 37134, Verona, VR, Italy
| | - Elisa Oppici
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada le Grazie 8, 37134, Verona, VR, Italy
| | - Veronica Ceccarelli
- Department of Experimental Medicine, University of Perugia, P.le Gambuli 1, 06132, Perugia, Italy
| | - Lorella Marinucci
- Department of Experimental Medicine, University of Perugia, P.le Gambuli 1, 06132, Perugia, Italy
| | - Barbara Cellini
- Department of Experimental Medicine, University of Perugia, P.le Gambuli 1, 06132, Perugia, Italy.
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15
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Bridges RJ, Bradbury NA. Cystic Fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator and Drugs: Insights from Cellular Trafficking. Handb Exp Pharmacol 2018; 245:385-425. [PMID: 29460152 DOI: 10.1007/164_2018_103] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The eukaryotic cell is organized into membrane-delineated compartments that are characterized by specific cadres of proteins sustaining biochemically distinct cellular processes. The appropriate subcellular localization of proteins is key to proper organelle function and provides a physiological context for cellular processes. Disruption of normal trafficking pathways for proteins is seen in several genetic diseases, where a protein's absence for a specific subcellular compartment leads to organelle disruption, and in the context of an individual, a disruption of normal physiology. Importantly, several drug therapies can also alter protein trafficking, causing unwanted side effects. Thus, a deeper understanding of trafficking pathways needs to be appreciated as novel therapeutic modalities are proposed. Despite the promising efficacy of novel therapeutic agents, the intracellular bioavailability of these compounds has proved to be a potential barrier, leading to failures in treatments for various diseases and disorders. While endocytosis of drug moieties provides an efficient means of getting material into cells, the subsequent release and endosomal escape of materials into the cytosol where they need to act has been a barrier. An understanding of cellular protein/lipid trafficking pathways has opened up strategies for increasing drug bioavailability. Approaches to enhance endosomal exit have greatly increased the cytosolic bioavailability of drugs and will provide a means of investigating previous drugs that may have been shelved due to their low cytosolic concentration.
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Affiliation(s)
- Robert J Bridges
- Department of Physiology and Biophysics, Chicago Medical School, North Chicago, IL, USA
| | - Neil A Bradbury
- Department of Physiology and Biophysics, Chicago Medical School, North Chicago, IL, USA.
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16
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Oppici E, Dindo M, Conter C, Borri Voltattorni C, Cellini B. Folding Defects Leading to Primary Hyperoxaluria. Handb Exp Pharmacol 2018; 245:313-343. [PMID: 29071511 DOI: 10.1007/164_2017_59] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Protein misfolding is becoming one of the main mechanisms underlying inherited enzymatic deficits. This review is focused on primary hyperoxalurias, a group of disorders of glyoxylate detoxification associated with massive calcium oxalate deposition mainly in the kidneys. The most common and severe form, primary hyperoxaluria Type I, is due to the deficit of liver peroxisomal alanine/glyoxylate aminotransferase (AGT). Various studies performed in the last decade clearly evidence that many pathogenic missense mutations prevent the AGT correct folding, leading to various downstream effects including aggregation, increased degradation or mistargeting to mitochondria. Primary hyperoxaluria Type II and primary hyperoxaluria Type III are due to the deficit of glyoxylate reductase/hydroxypyruvate reductase (GRHPR) and 4-hydroxy-2-oxoglutarate aldolase (HOGA1), respectively. Although the molecular features of pathogenic variants of GRHPR and HOGA1 have not been investigated in detail, the data available suggest that some of them display folding defects. Thus, primary hyperoxalurias can be ranked among protein misfolding disorders, because in most cases the enzymatic deficit is due to the inability of each enzyme to reach its native and functional conformation. It follows that molecules able to improve the folding yield of the enzymes involved in each disease form could represent new therapeutic strategies.
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Affiliation(s)
- Elisa Oppici
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Mirco Dindo
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Carolina Conter
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Carla Borri Voltattorni
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy.
| | - Barbara Cellini
- Department of Experimental Medicine, University of Perugia, Piazzale Gambuli 1, 06132, Perugia, Italy.
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17
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Martin-Higueras C, Torres A, Salido E. Molecular therapy of primary hyperoxaluria. J Inherit Metab Dis 2017; 40:481-489. [PMID: 28425073 DOI: 10.1007/s10545-017-0045-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/20/2017] [Accepted: 04/03/2017] [Indexed: 12/19/2022]
Abstract
During the last few decades, the molecular understanding of the mechanisms involved in primary hyperoxalurias (PHs) has set the stage for novel therapeutic approaches. The availability of PH mouse models has facilitated preclinical studies testing innovative treatments. PHs are autosomal recessive diseases where the enzymatic deficit plays a central pathogenic role. Thus, molecular therapies aimed at restoring such deficit or limiting the consequences of the metabolic derangement could be envisioned, keeping in mind the specific challenges posed by the cell-autonomous nature of the deficiency. Various molecular approaches like enzyme replacement, substrate reduction, pharmacologic chaperones, and gene and cell therapies have been explored in cells and mouse models of disease. Some of these proof-of-concept studies have paved the way to current clinical trials on PH type 1, raising hopes that much needed treatments will become available for this severe inborn error of metabolism.
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Affiliation(s)
- Cristina Martin-Higueras
- Department of Pathology & Nephrology, Centre for Biomedical Research on Rare Diseases (CIBERER) Hospital Universitario Canarias, Universidad La Laguna, Tenerife, Spain
| | - Armando Torres
- Department of Pathology & Nephrology, Centre for Biomedical Research on Rare Diseases (CIBERER) Hospital Universitario Canarias, Universidad La Laguna, Tenerife, Spain
| | - Eduardo Salido
- Department of Pathology & Nephrology, Centre for Biomedical Research on Rare Diseases (CIBERER) Hospital Universitario Canarias, Universidad La Laguna, Tenerife, Spain.
- Department of Pathology, ULL School Medicine, 38320, Tenerife, Spain.
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18
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Paßlack N, Zentek J, Larsen JA, Westropp JL, Fascetti AJ. Impact of hyperlipidaemia on intermediary metabolism, faecal microbial metabolites and urinary characteristics of lipoprotein lipase deficient vs. normal cats. J Anim Physiol Anim Nutr (Berl) 2017; 102:e139-e146. [PMID: 28493444 DOI: 10.1111/jpn.12721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 03/02/2017] [Indexed: 12/12/2022]
Abstract
Findings in humans and rats indicate that hyperlipidaemia may be associated with enhanced endogenous oxalate (Ox) synthesis, which may be relevant for calcium oxalate (CaOx) urolith formation. Moreover, changes in lipid metabolism are proposed to negatively affect gut microbiota. This study aimed to investigate those potential interactions in hyperlipidaemic cats. Therefore, 10 normal control cats and seven lipoprotein lipase (LPL)-deficient cats were fed a low-fat diet for seven weeks. During the last week of the study, cats were housed in metabolic cages to collect urine and faeces. Blood was taken on the last day of the study. The LPL-deficient cats had significantly higher serum triglyceride concentrations than normal cats, while lactate dehydrogenase (LDH) activity was not different. Urinary relative supersaturation with CaOx, urinary Ox, calcium, and citrate excretions, and urine pH did not differ between groups. Lower faecal acetic, propionic and total short-chain fatty acid concentrations were observed in the LPL-deficient cats. In conclusion, hyperlipidaemia does not appear to be a specific risk factor for CaOx urolith formation in cats. In contrast to results in rats, hyperlipidaemia was not accompanied by elevated serum LDH activity. As LDH can synthesise Ox from glycolate or other precursors, this might be one possible explanation for the similar urinary parameters in the LPL-deficient and normal cats. Non-diet-induced hyperlipidaemia was not associated with marked changes in faecal microbial metabolites, suggesting no differences in the composition of the intestinal microbiota.
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Affiliation(s)
- N Paßlack
- Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - J Zentek
- Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - J A Larsen
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - J L Westropp
- Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - A J Fascetti
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA, USA
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19
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Deb R, Nagotu S. Versatility of peroxisomes: An evolving concept. Tissue Cell 2017; 49:209-226. [DOI: 10.1016/j.tice.2017.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 02/04/2023]
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20
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Affiliation(s)
- Barbara Cellini
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Verona (VR), Italy
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21
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Hou S, Madoux F, Scampavia L, Janovick JA, Conn PM, Spicer TP. Drug Library Screening for the Identification of Ionophores That Correct the Mistrafficking Disorder Associated with Oxalosis Kidney Disease. SLAS DISCOVERY 2017; 22:887-896. [PMID: 28346094 DOI: 10.1177/2472555217689992] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Primary hyperoxaluria is the underlying cause of oxalosis and is a life-threatening autosomal recessive disease, for which treatment may require dialysis or dual liver-kidney transplantation. The most common primary hyperoxaluria type 1 (PH1) is caused by genetic mutations of a liver-specific enzyme alanine:glyoxylate aminotransferase (AGT), which results in the misrouting of AGT from the peroxisomes to the mitochondria. Pharmacoperones are small molecules with the ability to modify misfolded proteins and route them correctly within the cells, which may present an effective strategy to treat AGT misrouting in PH1 disorders. We miniaturized a cell-based high-content assay into 1536-well plate format and screened ~4200 pharmacologically relevant compounds including Food and Drug Administration, European Union, and Japanese-approved drugs. This assay employs CHO cells stably expressing AGT-170, a mutant that predominantly resides in the mitochondria, where we monitor for its relocation to the peroxisomes through automated image acquisition and analysis. The miniaturized 1536-well assay yielded a Z' averaging 0.70 ± 0.07. Three drugs were identified as potential pharmacoperones from this pilot screen, demonstrating the applicability of this assay for large-scale high-throughput screening.
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Affiliation(s)
- Shurong Hou
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA
| | - Franck Madoux
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA.,3 Amgen Inc., Thousand Oaks, CA
| | - Louis Scampavia
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA
| | - Jo Ann Janovick
- 2 Departments of Internal Medicine and Cell Biology/Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - P Michael Conn
- 2 Departments of Internal Medicine and Cell Biology/Biochemistry, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Timothy P Spicer
- 1 Department of Molecular Therapeutics, Scripps Research Institute Molecular Screening Center, Scripps Research Institute, Jupiter, FL, USA
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22
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High throughput cell-based assay for identification of glycolate oxidase inhibitors as a potential treatment for Primary Hyperoxaluria Type 1. Sci Rep 2016; 6:34060. [PMID: 27670739 PMCID: PMC5037430 DOI: 10.1038/srep34060] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 09/05/2016] [Indexed: 12/11/2022] Open
Abstract
Glycolate oxidase (GO) and alanine:glyoxylate aminotransferase (AGT) are both involved in the peroxisomal glyoxylate pathway. Deficiency in AGT function causes the accumulation of intracellular oxalate and the primary hyperoxaluria type 1 (PH1). AGT enhancers or GO inhibitors may restore the abnormal peroxisomal glyoxylate pathway in PH1 patients. With stably transformed cells which mimic the glyoxylate metabolic pathway, we developed an indirect glycolate cytotoxicity assay in a 1,536-well plate format for high throughput screening. This assay can be used to identify compounds that reduce indirect glycolate-induced cytotoxicity by either enhancing AGT activity or inhibiting GO. A pilot screen of 4,096 known compounds identified two membrane permeable GO inhibitors: dichromate salt and colistimethate. We also developed a GO enzyme assay using the hydrogen peroxide-Amplex red reporter system. The IC50 values of potassium dichromate, sodium dichromate, and colistimethate sodium were 0.096, 0.108, and 2.3 μM in the GO enzyme assay, respectively. Further enzyme kinetic study revealed that both types of compounds inhibit GO activity by the mixed linear inhibition. Our results demonstrate that the cell-based assay and GO enzyme assay developed in this study are useful for further screening of large compound libraries for drug development to treat PH1.
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23
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Reciprocal Control of Thyroid Binding and the Pipecolate Pathway in the Brain. Neurochem Res 2016; 42:217-243. [DOI: 10.1007/s11064-016-2015-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/15/2016] [Accepted: 07/22/2016] [Indexed: 12/21/2022]
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24
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Pagliarini R, Castello R, Napolitano F, Borzone R, Annunziata P, Mandrile G, De Marchi M, Brunetti-Pierri N, di Bernardo D. In Silico Modeling of Liver Metabolism in a Human Disease Reveals a Key Enzyme for Histidine and Histamine Homeostasis. Cell Rep 2016; 15:2292-2300. [PMID: 27239044 PMCID: PMC4906368 DOI: 10.1016/j.celrep.2016.05.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 03/29/2016] [Accepted: 04/28/2016] [Indexed: 12/29/2022] Open
Abstract
Primary hyperoxaluria type I (PH1) is an autosomal-recessive inborn error of liver metabolism caused by alanine:glyoxylate aminotransferase (AGT) deficiency. In silico modeling of liver metabolism in PH1 recapitulated accumulation of known biomarkers as well as alteration of histidine and histamine levels, which we confirmed in vitro, in vivo, and in PH1 patients. AGT-deficient mice showed decreased vascular permeability, a readout of in vivo histamine activity. Histamine reduction is most likely caused by increased catabolism of the histamine precursor histidine, triggered by rerouting of alanine flux from AGT to the glutamic-pyruvate transaminase (GPT, also known as the alanine-transaminase ALT). Alanine administration reduces histamine levels in wild-type mice, while overexpression of GPT in PH1 mice increases plasma histidine, normalizes histamine levels, restores vascular permeability, and decreases urinary oxalate levels. Our work demonstrates that genome-scale metabolic models are clinically relevant and can link genotype to phenotype in metabolic disorders. In silico model of liver metabolism reveals global metabolic alterations in PH1 Changes in amino acid metabolism in PH1 result in a reduction of histidine and histamine GPT overexpression normalizes histamine levels and reduces oxalate in PH1 mice
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Affiliation(s)
| | | | | | - Roberta Borzone
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy
| | | | - Giorgia Mandrile
- Medical Genetics, San Luigi University Hospital, 10043 Orbassano, Italy; Department of Clinical & Biological Sciences, University of Turin, 10043 Orbassano, Italy
| | - Mario De Marchi
- Medical Genetics, San Luigi University Hospital, 10043 Orbassano, Italy; Department of Clinical & Biological Sciences, University of Turin, 10043 Orbassano, Italy
| | - Nicola Brunetti-Pierri
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; Department of Translational Medicine, Federico II University, 80131 Naples, Italy.
| | - Diego di Bernardo
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; Department of Chemical, Materials and Industrial Engineering, Federico II University, 80125 Naples, Italy.
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25
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Freitas MO, Francisco T, Rodrigues TA, Lismont C, Domingues P, Pinto MP, Grou CP, Fransen M, Azevedo JE. The peroxisomal protein import machinery displays a preference for monomeric substrates. Open Biol 2016; 5:140236. [PMID: 25854684 PMCID: PMC4422123 DOI: 10.1098/rsob.140236] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Peroxisomal matrix proteins are synthesized on cytosolic ribosomes and transported by the shuttling receptor PEX5 to the peroxisomal membrane docking/translocation machinery, where they are translocated into the organelle matrix. Under certain experimental conditions this protein import machinery has the remarkable capacity to accept already oligomerized proteins, a property that has heavily influenced current models on the mechanism of peroxisomal protein import. However, whether or not oligomeric proteins are really the best and most frequent clients of this machinery remain unclear. In this work, we present three lines of evidence suggesting that the peroxisomal import machinery displays a preference for monomeric proteins. First, in agreement with previous findings on catalase, we show that PEX5 binds newly synthesized (monomeric) acyl-CoA oxidase 1 (ACOX1) and urate oxidase (UOX), potently inhibiting their oligomerization. Second, in vitro import experiments suggest that monomeric ACOX1 and UOX are better peroxisomal import substrates than the corresponding oligomeric forms. Finally, we provide data strongly suggesting that although ACOX1 lacking a peroxisomal targeting signal can be imported into peroxisomes when co-expressed with ACOX1 containing its targeting signal, this import pathway is inefficient.
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Affiliation(s)
- Marta O Freitas
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, Porto, Portugal
| | - Tânia Francisco
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, Porto, Portugal
| | - Tony A Rodrigues
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, Porto, Portugal Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Celien Lismont
- Departement Cellulaire en Moleculaire Geneeskunde, KU Leuven-Universiteit Leuven, Leuven, Belgium
| | - Pedro Domingues
- Departamento de Química, Universidade de Aveiro, Aveiro, Portugal
| | - Manuel P Pinto
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, Porto, Portugal
| | - Cláudia P Grou
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, Porto, Portugal
| | - Marc Fransen
- Departement Cellulaire en Moleculaire Geneeskunde, KU Leuven-Universiteit Leuven, Leuven, Belgium
| | - Jorge E Azevedo
- Organelle Biogenesis and Function Group, Instituto de Biologia Celular e Molecular (IBMC), Universidade do Porto, Porto, Portugal Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
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26
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Helper-dependent adenoviral vectors for liver-directed gene therapy of primary hyperoxaluria type 1. Gene Ther 2015; 23:129-34. [PMID: 26609667 PMCID: PMC4746739 DOI: 10.1038/gt.2015.107] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/27/2015] [Accepted: 11/03/2015] [Indexed: 12/15/2022]
Abstract
Primary hyperoxaluria type 1 (PH1) is an inborn error of liver metabolism due to deficiency of the peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT) which catalyzes conversion of glyoxylate into glycine. AGT deficiency results in overproduction of oxalate which ultimately leads to end-stage renal disease and death. Organ transplantation as either preemptive liver transplantation or combined liver/kidney transplantation is the only available therapy to prevent disease progression. Gene therapy is an attractive option to provide an alternative treatment for PH1. Towards this goal, we investigated helper-dependent adenoviral (HDAd) vectors for liver-directed gene therapy of PH1. Compared to saline controls, AGT-deficient mice injected with an HDAd encoding the AGT under the control of a liver-specific promoter showed a significant reduction of hyperoxaluria and less increase of urinary oxalate following challenge with Ethylene Glycol (EG), a precursor of glyoxylate. These studies may thus pave the way to clinical application of HDAd for PH1 gene therapy.
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27
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Madoux F, Janovick JA, Smithson D, Fargue S, Danpure CJ, Scampavia L, Chen YT, Spicer TP, Conn PM. Development of a phenotypic high-content assay to identify pharmacoperone drugs for the treatment of primary hyperoxaluria type 1 by high-throughput screening. Assay Drug Dev Technol 2015; 13:16-24. [PMID: 25710543 DOI: 10.1089/adt.2014.627] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Primary hyperoxaluria is a severe disease for which the best current therapy is dialysis or organ transplantation. These are risky, inconvenient, and costly procedures. In some patients, pyridoxine treatment can delay the need for these surgical procedures. The underlying cause of particular forms of this disease is the misrouting of a specific enzyme, alanine:glyoxylate aminotransferase (AGT), to the mitochondria instead of the peroxisomes. Pharmacoperones are small molecules that can rescue misfolded proteins and redirect them to their correct location, thereby restoring their function and potentially curing disease. In the present study, we miniaturized a cell-based assay to identify pharmacoperone drugs present in large chemical libraries to selectively correct AGT misrouting. This assay employs AGT-170, a mutant form of AGT that predominantly resides in the mitochondria, which we monitor for its relocation to the peroxisomes through automated image acquisition and analysis. Over the course of a pilot screen of 1,280 test compounds, we achieved an average Z'-factor of 0.72±0.02, demonstrating the suitability of this assay for HTS.
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Affiliation(s)
- Franck Madoux
- 1 Lead Identification Division, Translational Research Institute, Scripps Research Institute , Jupiter, Florida
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28
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Oppici E, Montioli R, Dindo M, Maccari L, Porcari V, Lorenzetto A, Chellini S, Voltattorni CB, Cellini B. The Chaperoning Activity of Amino-oxyacetic Acid on Folding-Defective Variants of Human Alanine:Glyoxylate Aminotransferase Causing Primary Hyperoxaluria Type I. ACS Chem Biol 2015; 10:2227-36. [PMID: 26161999 DOI: 10.1021/acschembio.5b00480] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The rare disease Primary Hyperoxaluria Type I (PH1) results from the deficit of liver peroxisomal alanine:glyoxylate aminotransferase (AGT), as a consequence of inherited mutations on the AGXT gene frequently leading to protein misfolding. Pharmacological chaperone (PC) therapy is a newly developed approach for misfolding diseases based on the use of small molecule ligands able to promote the correct folding of a mutant enzyme. In this report, we describe the interaction of amino-oxyacetic acid (AOA) with the recombinant purified form of two polymorphic species of AGT, AGT-Ma and AGT-Mi, and with three pathogenic variants bearing previously identified folding defects: G41R-Ma, G170R-Mi, and I244T-Mi. We found that for all these enzyme AOA (i) forms an oxime at the active site, (ii) behaves as a slow, tight-binding inhibitor with KI values in the nanomolar range, and (iii) increases the thermal stability. Furthermore, experiments performed in mammalian cells revealed that AOA acts as a PC by partly preventing the intracellular aggregation of G41R-Ma and by promoting the correct peroxisomal import of G170R-Mi and I244T-Mi. Based on these data, we carried out a small-scale screening campaign. We identified four AOA analogues acting as AGT inhibitors, even if only one was found to act as a PC. The possible relationship between the structure and the PC activity of these compounds is discussed. Altogether, these results provide the proof-of-principle for the feasibility of a therapy with PCs for PH1-causing variants bearing folding defects and provide the scaffold for the identification of more specific ligands.
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Affiliation(s)
- Elisa Oppici
- Department
of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8 37134 Verona, Italy
| | - Riccardo Montioli
- Department
of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8 37134 Verona, Italy
| | - Mirco Dindo
- Department
of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8 37134 Verona, Italy
| | - Laura Maccari
- Siena Biotech S.p.A., Strada
del Petriccio e Belriguardo, 35 53100 Siena, Italy
| | - Valentina Porcari
- Siena Biotech S.p.A., Strada
del Petriccio e Belriguardo, 35 53100 Siena, Italy
| | - Antonio Lorenzetto
- Department
of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8 37134 Verona, Italy
| | - Sara Chellini
- Siena Biotech S.p.A., Strada
del Petriccio e Belriguardo, 35 53100 Siena, Italy
| | - Carla Borri Voltattorni
- Department
of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8 37134 Verona, Italy
| | - Barbara Cellini
- Department
of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8 37134 Verona, Italy
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29
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Montioli R, Oppici E, Dindo M, Roncador A, Gotte G, Cellini B, Borri Voltattorni C. Misfolding caused by the pathogenic mutation G47R on the minor allele of alanine:glyoxylate aminotransferase and chaperoning activity of pyridoxine. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1280-9. [DOI: 10.1016/j.bbapap.2015.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/03/2015] [Indexed: 12/22/2022]
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30
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Kunze M, Berger J. The similarity between N-terminal targeting signals for protein import into different organelles and its evolutionary relevance. Front Physiol 2015; 6:259. [PMID: 26441678 PMCID: PMC4585086 DOI: 10.3389/fphys.2015.00259] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/04/2015] [Indexed: 12/04/2022] Open
Abstract
The proper distribution of proteins between the cytosol and various membrane-bound compartments is crucial for the functionality of eukaryotic cells. This requires the cooperation between protein transport machineries that translocate diverse proteins from the cytosol into these compartments and targeting signal(s) encoded within the primary sequence of these proteins that define their cellular destination. The mechanisms exerting protein translocation differ remarkably between the compartments, but the predominant targeting signals for mitochondria, chloroplasts and the ER share the N-terminal position, an α-helical structural element and the removal from the core protein by intraorganellar cleavage. Interestingly, similar properties have been described for the peroxisomal targeting signal type 2 mediating the import of a fraction of soluble peroxisomal proteins, whereas other peroxisomal matrix proteins encode the type 1 targeting signal residing at the extreme C-terminus. The structural similarity of N-terminal targeting signals poses a challenge to the specificity of protein transport, but allows the generation of ambiguous targeting signals that mediate dual targeting of proteins into different compartments. Dual targeting might represent an advantage for adaptation processes that involve a redistribution of proteins, because it circumvents the hierarchy of targeting signals. Thus, the co-existence of two equally functional import pathways into peroxisomes might reflect a balance between evolutionary constant and flexible transport routes.
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Affiliation(s)
- Markus Kunze
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna Vienna, Austria
| | - Johannes Berger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna Vienna, Austria
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31
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Oppici E, Fargue S, Reid ES, Mills PB, Clayton PT, Danpure CJ, Cellini B. Pyridoxamine and pyridoxal are more effective than pyridoxine in rescuing folding-defective variants of human alanine:glyoxylate aminotransferase causing primary hyperoxaluria type I. Hum Mol Genet 2015. [DOI: 10.1093/hmg/ddv276] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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32
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Valente C, Alvarez L, Marks SJ, Lopez-Parra AM, Parson W, Oosthuizen O, Oosthuizen E, Amorim A, Capelli C, Arroyo-Pardo E, Gusmão L, Prata MJ. Exploring the relationship between lifestyles, diets and genetic adaptations in humans. BMC Genet 2015; 16:55. [PMID: 26018448 PMCID: PMC4445807 DOI: 10.1186/s12863-015-0212-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 04/30/2015] [Indexed: 12/05/2022] Open
Abstract
Background One of the most important dietary shifts underwent by human populations began to occur in the Neolithic, during which new modes of subsistence emerged and new nutrients were introduced in diets. This change might have worked as a selective pressure over the metabolic pathways involved in the breakdown of substances extracted from food. Here we applied a candidate gene approach to investigate whether in populations with different modes of subsistence, diet-related genetic adaptations could be identified in the genes AGXT, PLRP2, MTRR, NAT2 and CYP3A5. Results At CYP3A5, strong signatures of positive selection were detected, though not connected to any dietary variable, but instead to an environmental factor associated with the Tropic of Cancer. Suggestive signals of adaptions that could indeed be connected with differences in dietary habits of populations were only found for PLRP2 and NAT2. Contrarily, the demographic history of human populations seemed enough to explain patterns of diversity at AGXT and MTRR, once both conformed the evolutionary expectations under selective neutrality. Conclusions Accumulated evidence indicates that CYP3A5 has been under adaptive evolution during the history of human populations. PLRP2 and NAT2 also appear to have been modelled by some selective constrains, although clear support for that did not resist to a genome wide perspective. It is still necessary to clarify which were the biological mechanisms and the environmental factors involved as well as their interactions, to understand the nature and strength of the selective pressures that contributed to shape current patterns of genetic diversity at those loci. Electronic supplementary material The online version of this article (doi:10.1186/s12863-015-0212-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Cristina Valente
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal. .,Faculty of Sciences, University of Porto, Porto, Portugal.
| | - Luis Alvarez
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal.
| | - Sarah J Marks
- Department of Zoology, University of Oxford, Oxford, UK.
| | - Ana M Lopez-Parra
- Departamento de Toxicología y Legislación Sanitaria, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.
| | - Walther Parson
- Institute of Legal Medicine, Innsbruck Medical University, Innsbruck, Austria. .,Penn State Eberly College of Science, University Park, Pennsylvania, USA.
| | | | | | - António Amorim
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal. .,Faculty of Sciences, University of Porto, Porto, Portugal.
| | | | - Eduardo Arroyo-Pardo
- Departamento de Toxicología y Legislación Sanitaria, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain.
| | - Leonor Gusmão
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal. .,DNA Diagnostic Laboratory (LDD), State University of Rio de Janeiro (UERJ), Rio de Janeiro, Brazil.
| | - Maria J Prata
- IPATIMUP, Institute of Molecular Pathology and Immunology of the University of Porto, Porto, Portugal. .,Faculty of Sciences, University of Porto, Porto, Portugal.
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Mesa-Torres N, Tomic N, Albert A, Salido E, Pey AL. Molecular recognition of PTS-1 cargo proteins by Pex5p: implications for protein mistargeting in primary hyperoxaluria. Biomolecules 2015; 5:121-41. [PMID: 25689234 PMCID: PMC4384115 DOI: 10.3390/biom5010121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 02/05/2015] [Indexed: 01/29/2023] Open
Abstract
Peroxisomal biogenesis and function critically depends on the import of cytosolic proteins carrying a PTS1 sequence into this organelle upon interaction with the peroxin Pex5p. Recent structural studies have provided important insights into the molecular recognition of cargo proteins by Pex5p. Peroxisomal import is a key feature in the pathogenesis of primary hyperoxaluria type 1 (PH1), where alanine:glyoxylate aminotransferase (AGT) undergoes mitochondrial mistargeting in about a third of patients. Here, we study the molecular recognition of PTS1 cargo proteins by Pex5p using oligopeptides and AGT variants bearing different natural PTS1 sequences, and employing an array of biophysical, computational and cell biology techniques. Changes in affinity for Pex5p (spanning over 3–4 orders of magnitude) reflect different thermodynamic signatures, but overall bury similar amounts of molecular surface. Structure/energetic analyses provide information on the contribution of ancillary regions and the conformational changes induced in Pex5p and the PTS1 cargo upon complex formation. Pex5p stability in vitro is enhanced upon cargo binding according to their binding affinities. Moreover, we provide evidence that the rational modulation of the AGT: Pex5p binding affinity might be useful tools to investigate mistargeting and misfolding in PH1 by pulling the folding equilibria towards the native and peroxisomal import competent state.
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Affiliation(s)
- Noel Mesa-Torres
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain.
| | - Nenad Tomic
- Center for Biomedical Research on Rare Diseases (CIBERER), University Hospital of the Canary Islands and CIBICAN, University of La Laguna, 38320 Tenerife, Spain.
| | - Armando Albert
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física "Rocasolano", Consejo Superior de Investigaciones Científicas, C/Serrano 119, 28006 Madrid, Spain.
| | - Eduardo Salido
- Center for Biomedical Research on Rare Diseases (CIBERER), University Hospital of the Canary Islands and CIBICAN, University of La Laguna, 38320 Tenerife, Spain.
| | - Angel L Pey
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain.
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Liver peroxisomal alanine:glyoxylate aminotransferase and the effects of mutations associated with Primary Hyperoxaluria Type I: An overview. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1212-9. [PMID: 25620715 DOI: 10.1016/j.bbapap.2014.12.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/19/2014] [Accepted: 12/20/2014] [Indexed: 11/21/2022]
Abstract
Liver peroxisomal alanine:glyoxylate aminotransferase (AGT) (EC 2.6.1.44) catalyses the conversion of l-alanine and glyoxylate to pyruvate and glycine, a reaction that allows glyoxylate detoxification. Inherited mutations on the AGXT gene encoding AGT lead to Primary Hyperoxaluria Type I (PH1), a rare disorder characterized by the deposition of calcium oxalate crystals primarily in the urinary tract. Here we describe the results obtained on the biochemical features of AGT as well as on the molecular and cellular effects of polymorphic and pathogenic mutations. A complex scenario on the molecular pathogenesis of PH1 emerges in which the co-inheritance of polymorphic changes and the condition of homozygosis or compound heterozygosis are two important factors that determine the enzymatic phenotype of PH1 patients. All the reported data represent relevant steps toward the understanding of genotype/phenotype correlations, the prediction of the response of the patients to the available therapies, and the development of new therapeutic approaches. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.
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Dijcker JC, Hagen-Plantinga EA, Thomas DG, Queau Y, Biourge V, Hendriks WH. The effect of dietary hydroxyproline and dietary oxalate on urinary oxalate excretion in cats. J Anim Sci 2014; 92:577-84. [PMID: 24664562 DOI: 10.2527/jas.2013-6178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In humans and rodents, dietary hydroxyproline (hyp) and oxalate intake affect urinary oxalate (Uox) excretion. Whether Uox excretion occurs in cats was tested by feeding diets containing low oxalate (13 mg/100 g DM) with high (Hhyp-Lox), moderate (Mhyp-Lox), and low hyp (Lhyp-Lox) concentrations (3.8, 2.0, and 0.2 g/100 g DM, respectively) and low hyp with high oxalate (93 mg/100 g DM; Lhyp-Hox) to 8 adult female cats in a 48-d study using a Latin square design. Cats were randomly allocated to one of the four 12-d treatment periods and fed according to individual energy needs. Feces and urine were collected quantitatively using modified litter boxes during the final 5 d of each period. Feces were analyzed for oxalate and Ca, and urine was analyzed for specific density, pH, oxalate, Ca, P, Mg, Na, K, ammonia, citrate, urate, sulfate, and creatinine. Increasing hyp intake (0.2, 2.0, and 3.8 g/100 g DM) resulted in increased Uox excretion (Lhyp-Lox vs. Mhyp-Lox vs. Hhyp-Lox; P < 0.05), and the linear dose-response equation was Uox (mg/d) = 5.62 + 2.10 × g hyp intake/d (r(2) = 0.56; P < 0.001). Increasing oxalate intake from 13 to 93 mg/100 g DM did not affect Uox excretion but resulted in an increase in fecal oxalate output (P < 0.001) and positive oxalate balance (32.20 ± 2.06 mg/d). The results indicate that the intestinal absorption of the supplemental oxalate, and thereby its contribution to Uox, was low (5.90% ± 5.24%). Relevant increases in endogenous Uox excretion were achieved by increasing dietary hyp intake. The hyp-containing protein sources should be minimized in Ca oxalate urolith preventative diets until their effect on Uox excretion is tested. The oxalate content (up to 93 mg/100 g DM) in a diet with moderate Ca content does not contribute to Uox content.
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Affiliation(s)
- J C Dijcker
- Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
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36
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Fodor K, Wolf J, Reglinski K, Passon DM, Lou Y, Schliebs W, Erdmann R, Wilmanns M. Ligand-Induced Compaction of the PEX5 Receptor-Binding Cavity Impacts Protein Import Efficiency into Peroxisomes. Traffic 2014; 16:85-98. [DOI: 10.1111/tra.12238] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/03/2014] [Accepted: 11/03/2014] [Indexed: 01/22/2023]
Affiliation(s)
- Krisztián Fodor
- Hamburg Unit; European Molecular Biology Laboratory Hamburg Unit; Hamburg Germany
| | - Janina Wolf
- Department of Systems Biochemistry, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum; Bochum Germany
| | - Katharina Reglinski
- Department of Systems Biochemistry, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum; Bochum Germany
| | - Daniel M. Passon
- Hamburg Unit; European Molecular Biology Laboratory Hamburg Unit; Hamburg Germany
| | - Ye Lou
- Hamburg Unit; European Molecular Biology Laboratory Hamburg Unit; Hamburg Germany
| | - Wolfgang Schliebs
- Department of Systems Biochemistry, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum; Bochum Germany
| | - Ralf Erdmann
- Department of Systems Biochemistry, Faculty of Medicine, Institute of Biochemistry and Pathobiochemistry, Ruhr-University Bochum; Bochum Germany
| | - Matthias Wilmanns
- Hamburg Unit; European Molecular Biology Laboratory Hamburg Unit; Hamburg Germany
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37
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Pharmacologic rescue of an enzyme-trafficking defect in primary hyperoxaluria 1. Proc Natl Acad Sci U S A 2014; 111:14406-11. [PMID: 25237136 DOI: 10.1073/pnas.1408401111] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Primary hyperoxaluria 1 (PH1; Online Mendelian Inheritance in Man no. 259900), a typically lethal biochemical disorder, may be caused by the AGT(P11LG170R) allele in which the alanine:glyoxylate aminotransferase (AGT) enzyme is mistargeted from peroxisomes to mitochondria. AGT contains a C-terminal peroxisomal targeting sequence, but mutations generate an N-terminal mitochondrial targeting sequence that directs AGT from peroxisomes to mitochondria. Although AGT(P11LG170R) is functional, the enzyme must be in the peroxisome to detoxify glyoxylate by conversion to alanine; in disease, amassed glyoxylate in the peroxisome is transported to the cytosol and converted to oxalate by lactate dehydrogenase, leading to kidney failure. From a chemical genetic screen, we have identified small molecules that inhibit mitochondrial protein import. We tested whether one promising candidate, Food and Drug Administration (FDA)-approved dequalinium chloride (DECA), could restore proper peroxisomal trafficking of AGT(P11LG170R). Indeed, treatment with DECA inhibited AGT(P11LG170R) translocation into mitochondria and subsequently restored trafficking to peroxisomes. Previous studies have suggested that a mitochondrial uncoupler might work in a similar manner. Although the uncoupler carbonyl cyanide m-chlorophenyl hydrazone inhibited AGT(P11LG170R) import into mitochondria, AGT(P11LG170R) aggregated in the cytosol, and cells subsequently died. In a cellular model system that recapitulated oxalate accumulation, exposure to DECA reduced oxalate accumulation, similar to pyridoxine treatment that works in a small subset of PH1 patients. Moreover, treatment with both DECA and pyridoxine was additive in reducing oxalate levels. Thus, repurposing the FDA-approved DECA may be a pharmacologic strategy to treat PH1 patients with mutations in AGT because an additional 75 missense mutations in AGT may also result in mistrafficking.
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Montioli R, Roncador A, Oppici E, Mandrile G, Giachino DF, Cellini B, Borri Voltattorni C. S81L and G170R mutations causing Primary Hyperoxaluria type I in homozygosis and heterozygosis: an example of positive interallelic complementation. Hum Mol Genet 2014; 23:5998-6007. [PMID: 24990153 PMCID: PMC4204775 DOI: 10.1093/hmg/ddu329] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Primary Hyperoxaluria type I (PH1) is a rare disease due to the deficit of peroxisomal alanine:glyoxylate aminotransferase (AGT), a homodimeric pyridoxal-5'-phosphate (PLP) enzyme present in humans as major (Ma) and minor (Mi) allele. PH1-causing mutations are mostly missense identified in both homozygous and compound heterozygous patients. Until now, the pathogenesis of PH1 has been only studied by approaches mimicking homozygous patients, whereas the molecular aspects of the genotype-enzymatic-clinical phenotype relationship in compound heterozygous patients are completely unknown. Here, for the first time, we elucidate the enzymatic phenotype linked to the S81L mutation on AGT-Ma, relative to a PLP-binding residue, and how it changes when the most common mutation G170R on AGT-Mi, known to cause AGT mistargeting without affecting the enzyme functionality, is present in the second allele. By using a bicistronic eukaryotic expression vector, we demonstrate that (i) S81L-Ma is mainly in its apo-form and has a significant peroxisomal localization and (ii) S81L and G170R monomers interact giving rise to the G170R-Mi/S81L-Ma holo-form, which is imported into peroxisomes and exhibits an enhanced functionality with respect to the parental enzymes. These data, integrated with the biochemical features of the heterodimer and the homodimeric counterparts in their purified recombinant form, (i) highlight the molecular basis of the pathogenicity of S81L-Ma and (ii) provide evidence for a positive interallelic complementation between the S81L and G170R monomers. Our study represents a valid approach to investigate the molecular pathogenesis of PH1 in compound heterozygous patients.
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Affiliation(s)
- Riccardo Montioli
- Department of Life Sciences and Reproduction, University of Verona, Verona, Italy and
| | - Alessandro Roncador
- Department of Life Sciences and Reproduction, University of Verona, Verona, Italy and
| | - Elisa Oppici
- Department of Life Sciences and Reproduction, University of Verona, Verona, Italy and
| | - Giorgia Mandrile
- Department of Clinical and Biological Sciences, University of Torino, Torino, Italy
| | | | - Barbara Cellini
- Department of Life Sciences and Reproduction, University of Verona, Verona, Italy and
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Theka T, Rodgers AL, Webber D, O'Ryan C. Variability in kidney stone incidence between black and white South Africans: AGT Pro11Leu polymorphism is not a factor. J Endourol 2014; 28:577-81. [PMID: 24344980 DOI: 10.1089/end.2013.0617] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Kidney stone disease is rare in the South African black (B) population and more prevalent in the white (W) population. Genetic studies have not previously examined this anomaly. The AGT Pro11Leu polymorphism in the alanine:glyoxylate aminotransferase (AGT) enzyme has been suggested as possibly playing a role in the pathogenesis of idiopathic calcium oxalate kidney stones. The present study was undertaken to investigate whether differences occur in the frequency of this polymorphism in subjects of both race groups. MATERIALS AND METHODS Healthy B (n=60) and W (n=60) male subjects each provided early morning spot urine, blood, and buccal cell samples. The AGT Pro11Leu locus was amplified using the polymerase chain reaction and polymorphism was genotyped using a restriction fragment length polymorphism. RESULTS There was no difference in the frequency of the AGT Pro11Leu polymorphism, and the major allele (C) was present at a frequency of 0.82 in B and 0.83 in W. Thus, the most common genotype homozygous normal CC genotype was observed at similar frequencies in both groups (0.68 and 0.65 in B and W, respectively), as were the heterozygous CT genotype (CT) and the homozygous variant TT genotype (TT) genotypes (0.33 & 0.02 and 0.28 & 0.03 in B and W, respectively). Neither urinary oxalate nor any other component in the two groups was correlated with the frequency of the AGT Pro11Leu polymorphism. CONCLUSIONS Our data imply that the AGT Pro11Leu polymorphism is not directly responsible for the low incidence of stone formation in B. We conclude that other factors must be instrumental in protecting the B population from urolithiasis.
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Affiliation(s)
- Takalani Theka
- 1 Department of Chemistry, University of Cape Town , Cape Town, South Africa
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Klootwijk ED, Reichold M, Helip-Wooley A, Tolaymat A, Broeker C, Robinette SL, Reinders J, Peindl D, Renner K, Eberhart K, Assmann N, Oefner PJ, Dettmer K, Sterner C, Schroeder J, Zorger N, Witzgall R, Reinhold SW, Stanescu HC, Bockenhauer D, Jaureguiberry G, Courtneidge H, Hall AM, Wijeyesekera AD, Holmes E, Nicholson JK, O'Brien K, Bernardini I, Krasnewich DM, Arcos-Burgos M, Izumi Y, Nonoguchi H, Jia Y, Reddy JK, Ilyas M, Unwin RJ, Gahl WA, Warth R, Kleta R. Mistargeting of peroxisomal EHHADH and inherited renal Fanconi's syndrome. N Engl J Med 2014; 370:129-38. [PMID: 24401050 DOI: 10.1056/nejmoa1307581] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND In renal Fanconi's syndrome, dysfunction in proximal tubular cells leads to renal losses of water, electrolytes, and low-molecular-weight nutrients. For most types of isolated Fanconi's syndrome, the genetic cause and underlying defect remain unknown. METHODS We clinically and genetically characterized members of a five-generation black family with isolated autosomal dominant Fanconi's syndrome. We performed genomewide linkage analysis, gene sequencing, biochemical and cell-biologic investigations of renal proximal tubular cells, studies in knockout mice, and functional evaluations of mitochondria. Urine was studied with the use of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy. RESULTS We linked the phenotype of this family's Fanconi's syndrome to a single locus on chromosome 3q27, where a heterozygous missense mutation in EHHADH segregated with the disease. The p.E3K mutation created a new mitochondrial targeting motif in the N-terminal portion of EHHADH, an enzyme that is involved in peroxisomal oxidation of fatty acids and is expressed in the proximal tubule. Immunocytofluorescence studies showed mistargeting of the mutant EHHADH to mitochondria. Studies of proximal tubular cells revealed impaired mitochondrial oxidative phosphorylation and defects in the transport of fluids and a glucose analogue across the epithelium. (1)H-NMR spectroscopy showed elevated levels of mitochondrial metabolites in urine from affected family members. Ehhadh knockout mice showed no abnormalities in renal tubular cells, a finding that indicates a dominant negative nature of the mutation rather than haploinsufficiency. CONCLUSIONS Mistargeting of peroxisomal EHHADH disrupts mitochondrial metabolism and leads to renal Fanconi's syndrome; this indicates a central role of mitochondria in proximal tubular function. The dominant negative effect of the mistargeted protein adds to the spectrum of monogenic mechanisms of Fanconi's syndrome. (Funded by the European Commission Seventh Framework Programme and others.).
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Affiliation(s)
- Enriko D Klootwijk
- From the Centre for Nephrology (E.D.K., H.C.S., D.B., G.J., H.C., A.M.H., R.J.U., R.K.) and Institute of Child Health (D.B., R.K.), University College London, and Biomolecular Medicine, Imperial College London (S.L.R., A.D.W., E.H., J.K.N.) - both in London; the Departments of Medical Cell Biology (M.R., C.B., D.P., C.S., R. Warth), Internal Medicine III (K.R.), Internal Medicine II (S.W.R.), and Molecular and Cellular Anatomy (R. Witzgall) and the Institutes of Functional Genomics (J.R., K.E., N.A., P.J.O., K.D.) and Pathology (J.S.), University of Regensburg, and the Department of Radiology, Barmherzige Brueder Hospital (N.Z.) - all in Regensburg, Germany; the National Human Genome Research Institute (A.H.-W., S.L.R., H.C.S., K.O., I.B., D.M.K., W.A.G., R.K.) and National Heart, Lung, and Blood Institute (Y.I.), National Institutes of Health, Bethesda, MD; the Division of Pediatric Nephrology, University of Florida, Jacksonville (A.T., M.I.); the Genome Biology Department, Australian National University, Canberra, ACT, Australia (M.A.-B.); Kitasato University Medical Center, Saitama, Japan (H.N.); and the Department of Pathology, Northwestern University, Chicago (Y.J., J.K.R.)
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Khan A, Byer K, Khan SR. Exposure of Madin-Darby canine kidney (MDCK) cells to oxalate and calcium oxalate crystals activates nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase. Urology 2013; 83:510.e1-7. [PMID: 24360063 DOI: 10.1016/j.urology.2013.10.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 10/08/2013] [Accepted: 10/24/2013] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To investigate nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase activity in Madin-Darby canine kidney (MDCK) cells and the production of reactive oxygen species on exposure to oxalate (Ox) or calcium oxalate (CaOx) crystals. METHODS Monolayers of confluent Madin-Darby canine kidney cells were exposed to 100, 300, 500 μmol, 1 mmol Ox or 33, 66, 132 μg/cm(2) CaOx crystals for 15 minutes, 30 minutes, 1 hour, 2 hours, or 3 hours. After specified periods of exposure to Ox and CaOx crystals, lactate dehydrogenase release, trypan blue exclusion, activation of NADPH oxidase, and superoxide production were determined using standard procedures. The production of Nox4, a membrane associated subunit of the NADPH oxidase enzyme, was determined by western blot analysis. RESULTS Exposure to Ox and CaOx crystals leads to time- and concentration-dependent activation of NADPH oxidase. Western blot analysis showed an increase in the production of Nox4. The production of superoxide also changed in a time- and concentration-dependent manner, with maximum increases after 30-minute exposure to the highest concentrations of Ox and CaOx crystals. Longer exposures did not change the results or resulted in decreased activities. Exposure to higher concentrations also caused increased lactate dehydrogenase release and trypan blue exclusion indicating cell damage. CONCLUSION Results indicate that cells of the distal tubular origin are equipped with NADPH oxidase that is activated by exposures to Ox and CaOx crystals. Higher concentrations of both lead to cell injury, most probably through the increased reactive oxygen species production by the exposed cells.
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Affiliation(s)
- Aslam Khan
- Department of Pharmacy, Shaheed Benazir Bhutto University, Sheringal, Dir Upper, Khyber Pakhtunkhwa, Pakistan
| | - Karen Byer
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL
| | - Saeed R Khan
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL.
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Pey AL. Protein homeostasis disorders of key enzymes of amino acids metabolism: mutation-induced protein kinetic destabilization and new therapeutic strategies. Amino Acids 2013; 45:1331-41. [PMID: 24178766 DOI: 10.1007/s00726-013-1609-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 10/19/2013] [Indexed: 12/31/2022]
Abstract
Many inborn errors of amino acids metabolism are caused by single point mutations affecting the ability of proteins to fold properly (i.e., protein homeostasis), thus leading to enzyme loss-of-function. Mutations may affect protein homeostasis by altering intrinsic physical properties of the polypeptide (folding thermodynamics, and rates of folding/unfolding/misfolding) as well as the interaction of partially folded states with elements of the protein homeostasis network (such as molecular chaperones and proteolytic machineries). Understanding these mutational effects on protein homeostasis is required to develop new therapeutic strategies aimed to target specific features of the mutant polypeptide. Here, I review recent work in three different diseases of protein homeostasis associated to inborn errors of amino acids metabolism: phenylketonuria, inherited homocystinuria and primary hyperoxaluria type I. These three different genetic disorders involve proteins operating in different cell organelles and displaying different structural complexities. Mutations often decrease protein kinetic stability of the native state (i.e., its half-life for irreversible denaturation), which can be studied using simple kinetic models amenable to biophysical and biochemical characterization. Natural ligands and pharmacological chaperones are shown to stabilize mutant enzymes, thus supporting their therapeutic application to overcome protein kinetic destabilization. The role of molecular chaperones in protein folding and misfolding is also discussed as well as their potential pharmacological modulation as promising new therapeutic approaches. Since current available treatments for these diseases are either burdening or only successful in a fraction of patients, alternative treatments must be considered covering studies from protein structure and biophysics to studies in animal models and patients.
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Affiliation(s)
- Angel L Pey
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071, Granada, Spain,
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Mesa-Torres N, Fabelo-Rosa I, Riverol D, Yunta C, Albert A, Salido E, Pey AL. The role of protein denaturation energetics and molecular chaperones in the aggregation and mistargeting of mutants causing primary hyperoxaluria type I. PLoS One 2013; 8:e71963. [PMID: 24205397 PMCID: PMC3796444 DOI: 10.1371/journal.pone.0071963] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 07/05/2013] [Indexed: 11/24/2022] Open
Abstract
Primary hyperoxaluria type I (PH1) is a conformational disease which result in the loss of alanine:glyoxylate aminotransferase (AGT) function. The study of AGT has important implications for protein folding and trafficking because PH1 mutants may cause protein aggregation and mitochondrial mistargeting. We herein describe a multidisciplinary study aimed to understand the molecular basis of protein aggregation and mistargeting in PH1 by studying twelve AGT variants. Expression studies in cell cultures reveal strong protein folding defects in PH1 causing mutants leading to enhanced aggregation, and in two cases, mitochondrial mistargeting. Immunoprecipitation studies in a cell-free system reveal that most mutants enhance the interactions with Hsc70 chaperones along their folding process, while in vitro binding experiments show no changes in the interaction of folded AGT dimers with the peroxisomal receptor Pex5p. Thermal denaturation studies by calorimetry support that PH1 causing mutants often kinetically destabilize the folded apo-protein through significant changes in the denaturation free energy barrier, whereas coenzyme binding overcomes this destabilization. Modeling of the mutations on a 1.9 Å crystal structure suggests that PH1 causing mutants perturb locally the native structure. Our work support that a misbalance between denaturation energetics and interactions with chaperones underlie aggregation and mistargeting in PH1, suggesting that native state stabilizers and protein homeostasis modulators are potential drugs to restore the complex and delicate balance of AGT protein homeostasis in PH1.
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Affiliation(s)
- Noel Mesa-Torres
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain
| | - Israel Fabelo-Rosa
- Centre for Biomedical Research on Rare Diseases, Instituto Tecnologías Biomédicas, University of La Laguna, Tenerife, Spain
| | - Debora Riverol
- Centre for Biomedical Research on Rare Diseases, Instituto Tecnologías Biomédicas, University of La Laguna, Tenerife, Spain
| | - Cristina Yunta
- Department of Crystallography and Structural Biology, Instituto de Química Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Armando Albert
- Department of Crystallography and Structural Biology, Instituto de Química Física “Rocasolano”, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Eduardo Salido
- Centre for Biomedical Research on Rare Diseases, Instituto Tecnologías Biomédicas, University of La Laguna, Tenerife, Spain
- * E-mail: (ES); (ALP)
| | - Angel L. Pey
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain
- * E-mail: (ES); (ALP)
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44
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Peroxisomes: offshoots of the ER. Curr Opin Cell Biol 2013; 25:449-54. [DOI: 10.1016/j.ceb.2013.05.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/06/2013] [Accepted: 05/20/2013] [Indexed: 11/21/2022]
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45
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Protein homeostasis defects of alanine-glyoxylate aminotransferase: new therapeutic strategies in primary hyperoxaluria type I. BIOMED RESEARCH INTERNATIONAL 2013; 2013:687658. [PMID: 23956997 PMCID: PMC3730394 DOI: 10.1155/2013/687658] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 05/23/2013] [Indexed: 11/30/2022]
Abstract
Alanine-glyoxylate aminotransferase catalyzes the transamination between L-alanine and glyoxylate to produce pyruvate and glycine using pyridoxal 5′-phosphate (PLP) as cofactor. Human alanine-glyoxylate aminotransferase is a peroxisomal enzyme expressed in the hepatocytes, the main site of glyoxylate detoxification. Its deficit causes primary hyperoxaluria type I, a rare but severe inborn error of metabolism. Single amino acid changes are the main type of mutation causing this disease, and considerable effort has been dedicated to the understanding of the molecular consequences of such missense mutations. In this review, we summarize the role of protein homeostasis in the basic mechanisms of primary hyperoxaluria. Intrinsic physicochemical properties of polypeptide chains such as thermodynamic stability, folding, unfolding, and misfolding rates as well as the interaction of different folding states with protein homeostasis networks are essential to understand this disease. The view presented has important implications for the development of new therapeutic strategies based on targeting specific elements of alanine-glyoxylate aminotransferase homeostasis.
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46
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Tabak HF, Braakman I, Zand AVD. Peroxisome Formation and Maintenance Are Dependent on the Endoplasmic Reticulum. Annu Rev Biochem 2013; 82:723-44. [DOI: 10.1146/annurev-biochem-081111-125123] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Henk F. Tabak
- Section of Cellular Protein Chemistry, Faculty of Science, Utrecht University, NL-3584 CH Utrecht, the Netherlands;
| | - Ineke Braakman
- Section of Cellular Protein Chemistry, Faculty of Science, Utrecht University, NL-3584 CH Utrecht, the Netherlands;
| | - Adabella van der Zand
- Section of Cellular Protein Chemistry, Faculty of Science, Utrecht University, NL-3584 CH Utrecht, the Netherlands;
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Oppici E, Fodor K, Paiardini A, Williams C, Voltattorni CB, Wilmanns M, Cellini B. Crystal structure of the S187F variant of human liver alanine: glyoxylate [corrected] aminotransferase associated with primary hyperoxaluria type I and its functional implications. Proteins 2013; 81:1457-65. [PMID: 23589421 PMCID: PMC3810726 DOI: 10.1002/prot.24300] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/20/2013] [Accepted: 03/26/2013] [Indexed: 11/11/2022]
Abstract
The substitution of Ser187, a residue located far from the active site of human liver peroxisomal alanine:glyoxylate aminotransferase (AGT), by Phe gives rise to a variant associated with primary hyperoxaluria type I. Unexpectedly, previous studies revealed that the recombinant form of S187F exhibits a remarkable loss of catalytic activity, an increased pyridoxal 5′-phosphate (PLP) binding affinity and a different coenzyme binding mode compared with normal AGT. To shed light on the structural elements responsible for these defects, we solved the crystal structure of the variant to a resolution of 2.9 Å. Although the overall conformation of the variant is similar to that of normal AGT, we noticed: (i) a displacement of the PLP-binding Lys209 and Val185, located on the re and si side of PLP, respectively, and (ii) slight conformational changes of other active site residues, in particular Trp108, the base stacking residue with the pyridine cofactor moiety. This active site perturbation results in a mispositioning of the AGT-pyridoxamine 5′-phosphate (PMP) complex and of the external aldimine, as predicted by molecular modeling studies. Taken together, both predicted and observed movements caused by the S187F mutation are consistent with the following functional properties of the variant: (i) a 300- to 500-fold decrease in both the rate constant of L-alanine half-transamination and the kcat of the overall transamination, (ii) a different PMP binding mode and affinity, and (iii) a different microenvironment of the external aldimine. Proposals for the treatment of patients bearing S187F mutation are discussed on the basis of these results. Proteins 2013; 81:1457–1465. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Elisa Oppici
- Department of Life Sciences and Reproduction, Section of Biological Chemistry, University of Verona, Verona, Italy
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Pagliarini R, di Bernardo D. A genome-scale modeling approach to study inborn errors of liver metabolism: toward an in silico patient. J Comput Biol 2013; 20:383-97. [PMID: 23464878 PMCID: PMC3646339 DOI: 10.1089/cmb.2012.0276] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Inborn errors of metabolism (IEM) are genetic diseases caused by mutations in enzymes or transporters affecting specific metabolic reactions that cause a block in the physiological metabolic fluxes. Therapeutic treatment can be achieved either by decreasing the metabolic flux upstream of the block or by increasing the flux downstream of the block. The identification of upstream and downstream fluxes however is not trivial, since metabolic reactions are intertwined in a complex network. To overcome this problem, we propose an innovative computational workflow to model the alteration of metabolism caused by IEM and predict the metabolites and reactions that are affected by the mutation. Our workflow exploits a recent genome-scale metabolic network model of hepatocyte metabolism to identify metabolites accumulating in hepatocytes due to single gene mutations in IEM via an innovative "differential flux analysis." We simulated 38 IEMs in the liver, and in about half of the cases, our workflow correctly identified the metabolites known to accumulate in the blood and urine of IEM patients.
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Abstract
Accidental or intentional ingestion of substances containing methanol and ethylene glycol can result in death, and some survivors are left with blindness, renal dysfunction, and chronic brain injury. However, even in large ingestions, a favorable outcome is possible if the patient arrives at the hospital early enough and the poisoning is identified and appropriately treated in a timely manner. This review covers the common circumstances of exposure, the involved toxic mechanisms, and the clinical manifestations, laboratory findings, and treatment of methanol and ethylene glycol intoxication.
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Fargue S, Lewin J, Rumsby G, Danpure CJ. Four of the most common mutations in primary hyperoxaluria type 1 unmask the cryptic mitochondrial targeting sequence of alanine:glyoxylate aminotransferase encoded by the polymorphic minor allele. J Biol Chem 2012; 288:2475-84. [PMID: 23229545 DOI: 10.1074/jbc.m112.432617] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gene encoding the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase (AGT, EC. 2.6.1.44) exists as two common polymorphic variants termed the "major" and "minor" alleles. The P11L amino acid replacement encoded by the minor allele creates a hidden N-terminal mitochondrial targeting sequence, the unmasking of which occurs in the hereditary calcium oxalate kidney stone disease primary hyperoxaluria type 1 (PH1). This unmasking is due to the additional presence of a common disease-specific G170R mutation, which is encoded by about one third of PH1 alleles. The P11L and G170R replacements interact synergistically to reroute AGT to the mitochondria where it cannot fulfill its metabolic role (i.e. glyoxylate detoxification) effectively. In the present study, we have reinvestigated the consequences of the interaction between P11L and G170R in stably transformed CHO cells and have studied for the first time whether a similar synergism exists between P11L and three other mutations that segregate with the minor allele (i.e. I244T, F152I, and G41R). Our investigations show that the latter three mutants are all able to unmask the cryptic P11L-generated mitochondrial targeting sequence and, as a result, all are mistargeted to the mitochondria. However, whereas the G170R, I244T, and F152I mutants are able to form dimers and are catalytically active, the G41R mutant aggregates and is inactive. These studies open up the possibility that all PH1 mutations, which segregate with the minor allele, might also lead to the peroxisome-to-mitochondrion mistargeting of AGT, a suggestion that has important implications for the development of treatment strategies for PH1.
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Affiliation(s)
- Sonia Fargue
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
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