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Ohl L, Kuhs A, Pluck R, Durham E, Noji M, Philip ND, Arany Z, Ahrens-Nicklas RC. Partial suppression of BCAA catabolism as a potential therapy for BCKDK deficiency. Mol Genet Metab Rep 2024; 39:101091. [PMID: 38770403 PMCID: PMC11103483 DOI: 10.1016/j.ymgmr.2024.101091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 05/22/2024] Open
Abstract
Branched chain ketoacid dehydrogenase kinase (BCKDK) deficiency is a recently described inherited neurometabolic disorder of branched chain amino acid (BCAA) metabolism implying increased BCAA catabolism. It has been hypothesized that a severe reduction in systemic BCAA levels underlies the disease pathophysiology, and that BCAA supplementation may ameliorate disease phenotypes. To test this hypothesis, we characterized a recent mouse model of BCKDK deficiency and evaluated the efficacy of enteral BCAA supplementation in this model. Surprisingly, BCAA supplementation exacerbated neurodevelopmental deficits and did not correct biochemical abnormalities despite increasing systemic BCAA levels. These data suggest that aberrant flux through the BCAA catabolic pathway, not just BCAA insufficiency, may contribute to disease pathology. In support of this conclusion, genetic re-regulation of BCAA catabolism, through Dbt haploinsufficiency, partially rescued biochemical and behavioral phenotypes in BCKDK deficient mice. Collectively, these data raise into question assumptions widely made about the pathophysiology of BCKDK insufficiency and suggest a novel approach to develop potential therapies for this disease.
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Affiliation(s)
- Laura Ohl
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- College of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amanda Kuhs
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ryan Pluck
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emily Durham
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Michael Noji
- College of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nathan D. Philip
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Zoltan Arany
- Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rebecca C. Ahrens-Nicklas
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Yazdankhah M, Ghosh S, Liu H, Hose S, Zigler JS, Sinha D. Mitophagy in Astrocytes Is Required for the Health of Optic Nerve. Cells 2023; 12:2496. [PMID: 37887340 PMCID: PMC10605486 DOI: 10.3390/cells12202496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/28/2023] Open
Abstract
Mitochondrial dysfunction in astrocytes has been implicated in the development of various neurological disorders. Mitophagy, mitochondrial autophagy, is required for proper mitochondrial function by preventing the accumulation of damaged mitochondria. The importance of mitophagy, specifically in the astrocytes of the optic nerve (ON), has been little studied. We introduce an animal model in which two separate mutations act synergistically to produce severe ON degeneration. The first mutation is in Cryba1, which encodes βA3/A1-crystallin, a lens protein also expressed in astrocytes, where it regulates lysosomal pH. The second mutation is in Bckdk, which encodes branched-chain ketoacid dehydrogenase kinase, which is ubiquitously expressed in the mitochondrial matrix and involved in the catabolism of the branched-chain amino acids. BCKDK is essential for mitochondrial function and the amelioration of oxidative stress. Neither of the mutations in isolation has a significant effect on the ON, but animals homozygous for both mutations (DM) exhibit very serious ON degeneration. ON astrocytes from these double-mutant (DM) animals have lysosomal defects, including impaired mitophagy, and dysfunctional mitochondria. Urolithin A can rescue the mitophagy impairment in DM astrocytes and reduce ON degeneration. These data demonstrate that efficient mitophagy in astrocytes is required for ON health and functional integrity.
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Affiliation(s)
- Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
| | - J. Samuel Zigler
- Department of Ophthalmology, The Wilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA;
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; (S.G.); (H.L.); (S.H.); (D.S.)
- Department of Ophthalmology, The Wilmer Eye Institute, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA;
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3
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Ohl L, Kuhs A, Pluck R, Durham E, Noji M, Philip ND, Arany Z, Ahrens-Nicklas RC. Partial suppression of BCAA catabolism as a potential therapy for BCKDK deficiency. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.12.560929. [PMID: 37873402 PMCID: PMC10592755 DOI: 10.1101/2023.10.12.560929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Branched chain ketoacid dehydrogenase kinase (BCKDK) deficiency is a recently described inherited neurometabolic disorder of branched chain amino acid (BCAA) metabolism implying increased BCAA catabolism. It has been hypothesized that a severe reduction in systemic BCAA levels underlies the disease pathophysiology, and that BCAA supplementation may ameliorate disease phenotypes. To test this hypothesis, we characterized a recent mouse model of BCKDK deficiency and evaluated the efficacy of enteral BCAA supplementation in this model. Surprisingly, BCAA supplementation exacerbated neurodevelopmental deficits and did not correct biochemical abnormalities despite increasing systemic BCAA levels. These data suggest that aberrant flux through the BCAA catabolic pathway, not just BCAA insufficiency, may contribute to disease pathology. In support of this conclusion, genetic re-regulation of BCAA catabolism, through Dbt haploinsufficiency, partially rescued biochemical and behavioral phenotypes in BCKDK deficient mice. Collectively, these data raise into question assumptions widely made about the pathophysiology of BCKDK insufficiency and suggest a novel approach to develop potential therapies for this disease.
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4
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Liu S, Kormos BL, Knafels JD, Sahasrabudhe PV, Rosado A, Sommese RF, Reyes AR, Ward J, Roth Flach RJ, Wang X, Buzon LM, Reese MR, Bhattacharya SK, Omoto K, Filipski KJ. Structural studies identify angiotensin II receptor blocker-like compounds as branched-chain ketoacid dehydrogenase kinase inhibitors. J Biol Chem 2023; 299:102959. [PMID: 36717078 PMCID: PMC9976451 DOI: 10.1016/j.jbc.2023.102959] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/19/2023] [Accepted: 01/25/2023] [Indexed: 01/30/2023] Open
Abstract
The mammalian mitochondrial branched-chain ketoacid dehydrogenase (BCKD) complex is a multienzyme complex involved in the catabolism of branched-chain amino acids. BCKD is regulated by the BCKD kinase, or BCKDK, which binds to the E2 subunit of BCKD, phosphorylates its E1 subunit, and inhibits enzymatic activity. Inhibition of the BCKD complex results in increased levels of branched-chain amino acids and branched-chain ketoacids, and this buildup has been associated with heart failure, type 2 diabetes mellitus, and nonalcoholic fatty liver disease. To find BCKDK inhibitors for potential treatment of these diseases, we performed both NMR and virtual fragment screening and identified tetrazole-bearing fragments that bind BCKDK at multiple sites. Through structure-based virtual screening expanding from these fragments, the angiotensin receptor blocker class antihypertension drugs and angiotensin receptor blocker-like compounds were discovered to be potent BCKDK inhibitors, suggesting potential new avenues for heart failure treatment combining BCKDK inhibition and antihypertension.
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Affiliation(s)
- Shenping Liu
- Medicine Design, Pfizer Inc, Groton, Connecticut, USA.
| | | | | | | | - Amy Rosado
- Medicine Design, Pfizer Inc, Groton, Connecticut, USA
| | | | - Allan R Reyes
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts, USA
| | - Jessica Ward
- Internal Medicine Research Unit, Pfizer Inc, Cambridge, Massachusetts, USA
| | | | - Xiaochun Wang
- Medicine Design, Pfizer Inc, Groton, Connecticut, USA
| | | | | | | | - Kiyoyuki Omoto
- Medicine Design, Pfizer Inc, Cambridge, Massachusetts, USA
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5
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Bollinger E, Peloquin M, Libera J, Albuquerque B, Pashos E, Shipstone A, Hadjipanayis A, Sun Z, Xing G, Clasquin M, Stansfield JC, Tierney B, Gernhardt S, Siddall CP, Greizer T, Geoly FJ, Vargas SR, Gao LC, Williams G, Marshall M, Rosado A, Steppan C, Filipski KJ, Zhang BB, Miller RA, Roth Flach RJ. BDK inhibition acts as a catabolic switch to mimic fasting and improve metabolism in mice. Mol Metab 2022; 66:101611. [PMID: 36220546 PMCID: PMC9589198 DOI: 10.1016/j.molmet.2022.101611] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE Branched chain amino acid (BCAA) catabolic defects are implicated to be causal determinates of multiple diseases. This work aimed to better understand how enhancing BCAA catabolism affected metabolic homeostasis as well as the mechanisms underlying these improvements. METHODS The rate limiting step of BCAA catabolism is the irreversible decarboxylation by the branched chain ketoacid dehydrogenase (BCKDH) enzyme complex, which is post-translationally controlled through phosphorylation by BCKDH kinase (BDK). This study utilized BT2, a small molecule allosteric inhibitor of BDK, in multiple mouse models of metabolic dysfunction and NAFLD including the high fat diet (HFD) model with acute and chronic treatment paradigms, the choline deficient and methionine minimal high fat diet (CDAHFD) model, and the low-density lipoprotein receptor null mouse model (Ldlr-/-). shRNA was additionally used to knock down BDK in liver to elucidate liver-specific effects of BDK inhibition in HFD-fed mice. RESULTS A rapid improvement in insulin sensitivity was observed in HFD-fed and lean mice after BT2 treatment. Resistance to steatosis was assessed in HFD-fed mice, CDAHFD-fed mice, and Ldlr-/- mice. In all cases, BT2 treatment reduced steatosis and/or inflammation. Fasting and refeeding demonstrated a lack of response to feeding-induced changes in plasma metabolites including insulin and beta-hydroxybutyrate and hepatic gene changes in BT2-treated mice. Mechanistically, BT2 treatment acutely altered the expression of genes involved in fatty acid oxidation and lipogenesis in liver, and upstream regulator analysis suggested that BT2 treatment activated PPARα. However, BT2 did not directly activate PPARα in vitro. Conversely, shRNA-AAV-mediated knockdown of BDK specifically in liver in vivo did not demonstrate any effects on glycemia, steatosis, or PPARα-mediated gene expression in mice. CONCLUSIONS These data suggest that BT2 treatment acutely improves metabolism and liver steatosis in multiple mouse models. While many molecular changes occur in liver in BT2-treated mice, these changes were not observed in mice with AAV-mediated shRNA knockdown of BDK. All together, these data suggest that systemic BDK inhibition is required to improve metabolism and steatosis by prolonging a fasting signature in a paracrine manner. Therefore, BCAA may act as a "fed signal" to promote nutrient storage and reduced systemic BCAA levels as shown in this study via BDK inhibition may act as a "fasting signal" to prolong the catabolic state.
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Affiliation(s)
- Eliza Bollinger
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Matthew Peloquin
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Jenna Libera
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Bina Albuquerque
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Evanthia Pashos
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Arun Shipstone
- Inflammation & Immunology Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Angela Hadjipanayis
- Inflammation & Immunology Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Zhongyuan Sun
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Gang Xing
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Michelle Clasquin
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | | | | | | | - C. Parker Siddall
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Timothy Greizer
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Frank J. Geoly
- Drug Safety Research and Development, Pfizer Inc, Groton CT 06340, USA
| | - Sarah R. Vargas
- Drug Safety Research and Development, Pfizer Inc, Groton CT 06340, USA
| | - Lily C. Gao
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - George Williams
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | | | - Amy Rosado
- Medicine Design, Pfizer Inc, Groton, CT 06340, USA
| | | | | | - Bei B. Zhang
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Russell A. Miller
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA
| | - Rachel J. Roth Flach
- Internal Medicine Research Unit, Pfizer Inc, Cambridge MA 02139, USA,Corresponding author. Pfizer Inc, 1 Portland St, Cambridge MA 02139, USA.
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Du C, Liu WJ, Yang J, Zhao SS, Liu HX. The Role of Branched-Chain Amino Acids and Branched-Chain α-Keto Acid Dehydrogenase Kinase in Metabolic Disorders. Front Nutr 2022; 9:932670. [PMID: 35923208 PMCID: PMC9339795 DOI: 10.3389/fnut.2022.932670] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/16/2022] [Indexed: 12/16/2022] Open
Abstract
Branched-chain amino acids (BCAAs), composed of leucine, isoleucine, and valine, are important essential amino acids in human physiology. Decades of studies have revealed their roles in protein synthesis, regulating neurotransmitter synthesis, and the mechanistic target of rapamycin (mTOR). BCAAs are found to be related to many metabolic disorders, such as insulin resistance, obesity, and heart failure. Also, many diseases are related to the alteration of the BCAA catabolism enzyme branched-chain α-keto acid dehydrogenase kinase (BCKDK), including maple syrup urine disease, human autism with epilepsy, and so on. In this review, diseases and the corresponding therapies are discussed after the introduction of the catabolism and detection methods of BCAAs and BCKDK. Also, the interaction between microbiota and BCAAs is highlighted.
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Affiliation(s)
- Chuang Du
- Institute of Life Sciences, China Medical University, Shenyang, China
- Health Sciences Institute, China Medical University, Shenyang, China
- Liaoning Key Laboratory of Obesity and Glucose/Lipid Associated Metabolic Diseases, China Medical University, Shenyang, China
- Department of Gastroenterology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Wen-Jie Liu
- Institute of Life Sciences, China Medical University, Shenyang, China
- Health Sciences Institute, China Medical University, Shenyang, China
- Liaoning Key Laboratory of Obesity and Glucose/Lipid Associated Metabolic Diseases, China Medical University, Shenyang, China
| | - Jing Yang
- Institute of Life Sciences, China Medical University, Shenyang, China
- Health Sciences Institute, China Medical University, Shenyang, China
- Liaoning Key Laboratory of Obesity and Glucose/Lipid Associated Metabolic Diseases, China Medical University, Shenyang, China
| | - Shan-Shan Zhao
- Institute of Life Sciences, China Medical University, Shenyang, China
- Health Sciences Institute, China Medical University, Shenyang, China
- Liaoning Key Laboratory of Obesity and Glucose/Lipid Associated Metabolic Diseases, China Medical University, Shenyang, China
- Department of Gynecology, Cancer Hospital of China Medical University, Liaoning Cancer Hospital & Institute, Shenyang, China
- *Correspondence: Shan-Shan Zhao,
| | - Hui-Xin Liu
- Institute of Life Sciences, China Medical University, Shenyang, China
- Health Sciences Institute, China Medical University, Shenyang, China
- Liaoning Key Laboratory of Obesity and Glucose/Lipid Associated Metabolic Diseases, China Medical University, Shenyang, China
- Hui-Xin Liu,
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7
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Sivasangari K, Rajan KE. Prenatal exposure to valproic acid alters Reelin, NGF expressing neuron architecture and impairs social interaction in their autistic-like phenotype male offspring. Exp Brain Res 2022; 240:2005-2016. [PMID: 35648200 DOI: 10.1007/s00221-022-06386-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/08/2022] [Indexed: 11/26/2022]
Abstract
Maternal exposure to anti-epileptic drug Valproic acid (VPA) during pregnancy increases the risk for the development of autism spectrum disorders (ASD). In this study, we have examined whether prenatal exposure to VPA will alter expression of key genes, synaptic morphology of nerve growth factor (NGF) and Reelin expressing neurons in the cortex of male offspring. To characterize in animal models, rat fetuses were exposed to VPA on 12.5 gestational day. The offspring of the VPA-exposed individuals (42%) resembles ASD-related phenotype (facial malformation, crooked-like tail, flattened paw, toenails and in-turning-ankles). Furthermore, we have observed deficit in social interaction accompanied by deregulation in expression of genes such as Caspase-3, focal adhesion kinase (FAK), Reelin, glial fibrillary acidic protein (GFAP), proliferating cell nuclear antigen (PCNA) and NGF. Subsequently, immunohistochemistry analysis revealed that exposure to VPA alters the cytoarchitecture (area, diameter) and reduced the dendritic arborization of Reelin, NGF expressing neurons in cortex. The compromised neurodevelopment by altered expression of Caspase-3, FAK, Reelin, GFAP, PCNA and NGF may cause defects in neuronal architecture, synaptic formation, synaptic plasticity and neuronal communication which could be linked with observed ASD-like phenotype and deficit social interaction.
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Affiliation(s)
- Karunanithi Sivasangari
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620024, Tamil Nadu, India
| | - Koilmani Emmanuvel Rajan
- Behavioural Neuroscience Laboratory, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620024, Tamil Nadu, India.
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8
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A Gain-of-Function Mutation on BCKDK Gene and Its Possible Pathogenic Role in Branched-Chain Amino Acid Metabolism. Genes (Basel) 2022; 13:genes13020233. [PMID: 35205278 PMCID: PMC8872256 DOI: 10.3390/genes13020233] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/17/2022] [Accepted: 01/23/2022] [Indexed: 02/06/2023] Open
Abstract
BCKDK is an important key regulator of branched-chain ketoacid dehydrogenase complex activity by phosphorylating and so inactivating branched-chain ketoacid dehydrogenases, the rate-limiting enzyme of the branched-chain amino acid metabolism. We identified, by whole exome-sequencing analysis, the p.His162Gln variant of the BCKDK gene in a neonate, picked up by newborn screening, with a biochemical phenotype of a mild form of maple syrup urine disease (MSUD). The same biochemical and genetic picture was present in the father. Computational analysis of the mutation was performed to better understand its role. Extensive atomistic molecular dynamics simulations showed that the described mutation leads to a conformational change of the BCKDK protein, which reduces the effect of inhibitory binding bound to the protein itself, resulting in its increased activity with subsequent inactivation of BCKDC and increased plasmatic branched-chain amino acid levels. Our study describes the first evidence of the involvement of the BCKDK gene in a mild form of MSUD. Although further data are needed to elucidate the clinical relevance of the phenotype caused by this variant, awareness of this regulatory activation of BCKDK is very important, especially in newborn screening data interpretation.
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Vogrinc D, Goričar K, Dolžan V. Genetic Variability in Molecular Pathways Implicated in Alzheimer's Disease: A Comprehensive Review. Front Aging Neurosci 2021; 13:646901. [PMID: 33815092 PMCID: PMC8012500 DOI: 10.3389/fnagi.2021.646901] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 02/16/2021] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative disease, affecting a significant part of the population. The majority of AD cases occur in the elderly with a typical age of onset of the disease above 65 years. AD presents a major burden for the healthcare system and since population is rapidly aging, the burden of the disease will increase in the future. However, no effective drug treatment for a full-blown disease has been developed to date. The genetic background of AD is extensively studied; numerous genome-wide association studies (GWAS) identified significant genes associated with increased risk of AD development. This review summarizes more than 100 risk loci. Many of them may serve as biomarkers of AD progression, even in the preclinical stage of the disease. Furthermore, we used GWAS data to identify key pathways of AD pathogenesis: cellular processes, metabolic processes, biological regulation, localization, transport, regulation of cellular processes, and neurological system processes. Gene clustering into molecular pathways can provide background for identification of novel molecular targets and may support the development of tailored and personalized treatment of AD.
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Affiliation(s)
| | | | - Vita Dolžan
- Pharmacogenetics Laboratory, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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10
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Experimental Models to Study Autism Spectrum Disorders: hiPSCs, Rodents and Zebrafish. Genes (Basel) 2020; 11:genes11111376. [PMID: 33233737 PMCID: PMC7699923 DOI: 10.3390/genes11111376] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 10/26/2020] [Accepted: 11/18/2020] [Indexed: 02/07/2023] Open
Abstract
Autism Spectrum Disorders (ASD) affect around 1.5% of the global population, which manifest alterations in communication and socialization, as well as repetitive behaviors or restricted interests. ASD is a complex disorder with known environmental and genetic contributors; however, ASD etiology is far from being clear. In the past decades, many efforts have been put into developing new models to study ASD, both in vitro and in vivo. These models have a lot of potential to help to validate some of the previously associated risk factors to the development of the disorder, and to test new potential therapies that help to alleviate ASD symptoms. The present review is focused on the recent advances towards the generation of models for the study of ASD, which would be a useful tool to decipher the bases of the disorder, as well as to conduct drug screenings that hopefully lead to the identification of useful compounds to help patients deal with the symptoms of ASD.
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11
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Yazdankhah M, Shang P, Ghosh S, Hose S, Liu H, Weiss J, Fitting CS, Bhutto IA, Zigler JS, Qian J, Sahel JA, Sinha D, Stepicheva NA. Role of glia in optic nerve. Prog Retin Eye Res 2020; 81:100886. [PMID: 32771538 DOI: 10.1016/j.preteyeres.2020.100886] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/09/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022]
Abstract
Glial cells are critically important for maintenance of neuronal activity in the central nervous system (CNS), including the optic nerve (ON). However, the ON has several unique characteristics, such as an extremely high myelination level of retinal ganglion cell (RGC) axons throughout the length of the nerve (with virtually all fibers myelinated by 7 months of age in humans), lack of synapses and very narrow geometry. Moreover, the optic nerve head (ONH) - a region where the RGC axons exit the eye - represents an interesting area that is morphologically distinct in different species. In many cases of multiple sclerosis (demyelinating disease of the CNS) vision problems are the first manifestation of the disease, suggesting that RGCs and/or glia in the ON are more sensitive to pathological conditions than cells in other parts of the CNS. Here, we summarize current knowledge on glial organization and function in the ON, focusing on glial support of RGCs. We cover both well-established concepts on the important role of glial cells in ON health and new findings, including novel insights into mechanisms of remyelination, microglia/NG2 cell-cell interaction, astrocyte reactivity and the regulation of reactive astrogliosis by mitochondrial fragmentation in microglia.
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Affiliation(s)
- Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Joseph Weiss
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Christopher S Fitting
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Imran A Bhutto
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - J Samuel Zigler
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiang Qian
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Institut de la Vision, INSERM, CNRS, Sorbonne Université, F-75012, Paris, France
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Nadezda A Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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12
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Szpirer C. Rat models of human diseases and related phenotypes: a systematic inventory of the causative genes. J Biomed Sci 2020; 27:84. [PMID: 32741357 PMCID: PMC7395987 DOI: 10.1186/s12929-020-00673-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
The laboratory rat has been used for a long time as the model of choice in several biomedical disciplines. Numerous inbred strains have been isolated, displaying a wide range of phenotypes and providing many models of human traits and diseases. Rat genome mapping and genomics was considerably developed in the last decades. The availability of these resources has stimulated numerous studies aimed at discovering causal disease genes by positional identification. Numerous rat genes have now been identified that underlie monogenic or complex diseases and remarkably, these results have been translated to the human in a significant proportion of cases, leading to the identification of novel human disease susceptibility genes, helping in studying the mechanisms underlying the pathological abnormalities and also suggesting new therapeutic approaches. In addition, reverse genetic tools have been developed. Several genome-editing methods were introduced to generate targeted mutations in genes the function of which could be clarified in this manner [generally these are knockout mutations]. Furthermore, even when the human gene causing a disease had been identified without resorting to a rat model, mutated rat strains (in particular KO strains) were created to analyze the gene function and the disease pathogenesis. Today, over 350 rat genes have been identified as underlying diseases or playing a key role in critical biological processes that are altered in diseases, thereby providing a rich resource of disease models. This article is an update of the progress made in this research and provides the reader with an inventory of these disease genes, a significant number of which have similar effects in rat and humans.
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Affiliation(s)
- Claude Szpirer
- Université Libre de Bruxelles, B-6041, Gosselies, Belgium.
- , Waterloo, Belgium.
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Wang L, Li NN, Lu ZJ, Li JY, Peng JX, Duan LR, Peng R. Association of three candidate genetic variants in ACMSD/TMEM163, GPNMB and BCKDK /STX1B with sporadic Parkinson's disease in Han Chinese. Neurosci Lett 2019; 703:45-48. [PMID: 30880162 DOI: 10.1016/j.neulet.2019.03.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/18/2019] [Accepted: 03/12/2019] [Indexed: 02/05/2023]
Abstract
Large-scale meta-analyses of genome-wide association studies have identified that polymorphisms ACMSD/TMEM163 rs6430538, GPNMB rs199347 and BCKDK /STX1B rs14235 to be the risk loci for Parkinson's disease (PD) in a Caucasian population. However, the role of these three polymorphisms in a Han Chinese population from mainland China still remains to be clarified. We conducted a large sample study to examine genetic associations of rs6430538, rs199347 and rs14235 with PD in a Han Chinese population of 989 sporadic PD patients and 1058 healthy controls. All subjects were genotyped for these loci using the Sequenom iPLEX Assay. In addition, we conducted further stratified analysis according to age at onset and compared the clinical characteristics between minor allele carriers and non-carriers for each locus. However, no significant differences were found in genotype and allele frequency distribution between PD patients and controls for the three loci, even after being stratified by age at onset. Moreover, we demonstrated that minor allele carriers cannot be distinguished from non-carriers based on their clinical features. Our study is the first to demonstrate that ACMSD/TMEM163 rs6430538, GPNMB rs199347 and BCKDK /STX1B rs14235 do not confer a significant risk for sporadic PD in mainland China. Therefore, more replication studies in additional Chinese population and other cohorts and functional studies are warranted to further clarify the role of the three loci in PD susceptibility.
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Affiliation(s)
- Ling Wang
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | - Nan-Nan Li
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | - Zhong-Jiao Lu
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | - Jun-Ying Li
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | - Jia-Xin Peng
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | - Li-Ren Duan
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China
| | - Rong Peng
- Department of Neurology, West China Hospital, Sichuan University, Sichuan, China.
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