scholarly journals Targeting pathogenic Lafora bodies in Lafora disease using an antibody-enzyme fusion

2019 ◽  
Author(s):  
M. Kathryn Brewer ◽  
Annette Uittenbogaard ◽  
Grant Austin ◽  
John J. McCarthy ◽  
Dyann M. Segvich ◽  
...  
Keyword(s):  
Glycogen Synthesis ◽  
Intractable Epilepsy ◽  
Antibody Fragment ◽  
Glycogen Storage ◽  
Childhood Epilepsy ◽  
Lafora Disease ◽  
Polyglucosan Bodies ◽  
Lafora Bodies ◽  
Enzyme Fusion

AbstractLafora disease (LD) is a fatal childhood epilepsy and a non-classical glycogen storage disorder with no effective therapy or cure. LD is caused by recessive mutations in theEPM2AorEPM2Bgenes that encode the glycogen phosphatase laforin and an E3 ubiquitin ligase malin, respectively. A hallmark of LD is the intracellular accumulation of abnormal and insoluble α-linked polysaccharide deposits known as Lafora bodies (LBs) in several tissues, including most regions of the brain. In mouse models of LD, genetic reduction of glycogen synthesis eliminates LB formation and rescues the neurological phenotype. Since multiple groups have confirmed that neurodegeneration and epilepsy result from LB accumulation, a major focus in the field has shifted toward the development of therapies that reduce glycogen synthesis or target LBs for degradation with the goal of treating LD. Herein, we identify the optimal enzymes for degrading LBs, and we develop a novel therapeutic agent by fusing human pancreatic α-amylase to a cellpenetrating antibody fragment. This antibody-enzyme fusion (VAL-0417) degrades LBsin vitro, shows robust cellular uptake, and significantly reduces the LB loadin vivoinEpm2a-/- mice. VAL-0417 is a promising therapeutic for the treatment of LD and a putative precision therapy for an intractable epilepsy. Antibody-enzyme fusions represent a new class of antibody-based drugs that could be utilized to treat glycogen storage disorders and other diseases.One Sentence SummaryAn antibody-enzyme fusion delivering an amylase degrades the toxic polyglucosan bodies that cause Lafora disease, a fatal childhood epilepsy.

Accelerated glycogenolysis in uremia and under sucrose feeding: role of phosphorylase alpha regulators

1997 ◽  
Vol 273 (1) ◽  
pp. E17-E27
Author(s):  
Z. Bakkour ◽  
D. Laouari ◽  
S. Dautrey ◽  
J. P. Yvert ◽  
C. Kleinknecht
Keyword(s):  
Hepatic Glucose Production ◽  
Glycogen Synthesis ◽  
Glucose Production ◽  
Glycogen Storage ◽  
Hepatic Insulin Resistance ◽  
Hepatic Glycogen ◽  
Glycogen Depletion ◽  
Sucrose Feeding

To understand the mechanism of hepatic glycogen depletion found in uremia and under sucrose feeding, we examined net hepatic glycogenolysis-associated active enzymes and metabolites during fasting. Liver was taken 2, 7, and 18 h after food removal in uremic and pair-fed control rats fed either a sucrose or cornstarch diet for 21 days. Other uremic and control rats fasted for 18 h were refed a sucrose meal to measure glycogen increment. Glycogen storage in uremia was normal, suggesting effective glycogen synthesis. During a short fast, sucrose feeding and uremia enhanced net glycogenolysis through different but additive mechanisms. Under sucrose feeding, there were high phosphorylase alpha levels associated with hepatic insulin resistance. In uremia, phosphorylase alpha levels were low, but the enzyme was probably activated in vivo by a fall of inhibitors (ATP, alpha-glycerophosphate, fructose-1,6-diphosphate, and glucose) and a rise of Pi, as verified in vitro. Enhanced gluconeogenesis was also suggested, but excessive hepatic glucose production was unlikely in uremia. During fasting, hypoglycemia occurred in uremia due to reduced glycogenolysis, inefficient hepatic gluconeogenesis, and impaired renal gluconeogenesis. This may be relevant to poor fasting tolerance in uremia, which could be aggravated under excessive sucrose intake.

scholarly journals Central Nervous System Delivery and Biodistribution Analysis of an Antibody-Enzyme Fusion for the Treatment of Lafora Disease

2019 ◽  
Author(s):  
Grant L. Austin ◽  
Zoe R. Simmons ◽  
Jack E. Klier ◽  
Brad L. Hodges ◽  
Robert Shaffer ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Intrathecal Administration ◽  
Lafora Disease ◽  
Cell Penetration ◽  
Unique Challenge ◽  
Cellular Targeting ◽  
Lafora Bodies ◽  
Murine Systemic Lupus Erythematosus ◽  
Mediate Cell ◽  
Enzyme Fusion

AbstractLafora disease is a fatal juvenile epilepsy, characterized by the malignant accumulation of aberrant glucan inclusions called Lafora Bodies (LBs). Cerebral delivery of protein-based therapeutics for the clearance of Lafora Bodies remain a unique challenge in the field. Recently, a humanized antigen-binding fragment (hFab) derived from a murine systemic lupus erythematosus DNA autoantibody (3E10) has been shown to mediate cell penetration and been proposed as a broadly applicable carrier to mediate cellular targeting and uptake. We report studies on cerebral delivery of VAL-0417, an antibody-enzyme fusion composed of the 3E10 hFab and human pancreatic α-amylase for the clearance of LBs in a mouse model of lafora disease. Herein, we report development of an enzyme-linked immunosorbant-based bioassay to detect VAL-0417 post treatment as a measure of delivery efficacy. We demonstrate the robust and sensitive detection of the fusion protein in multiple tissue types. Using our method, we measured biodistribution in different methods of delivery. We found intracerebroventricular administration provided the most robust delivery, while intrathecal administration only showed modest biodistribution. These data define critical steps in the translational pipeline of VAL-0417for the treatment of Lafora disease.

Astrocytic glycogen accumulation drives the pathophysiology of neurodegeneration in Lafora disease

Brain ◽  
2021 ◽  
Author(s):  
Jordi Duran ◽  
Arnau Hervera ◽  
Kia H Markussen ◽  
Olga Varea ◽  
Iliana López-Soldado ◽  
...  
Keyword(s):  
Mouse Model ◽  
Neurodegenerative Disorder ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
Glycogen Metabolism ◽  
Cell Type ◽  
Lafora Disease ◽  
Glycogen Accumulation ◽  
Lafora Bodies

Abstract The hallmark of Lafora disease, a fatal neurodegenerative disorder, is the accumulation of intracellular glycogen aggregates, called Lafora bodies. Until recently, it was widely believed that brain Lafora bodies were present exclusively in neurons and thus that Lafora disease pathology derived from their accumulation in this cell population. However, recent evidence indicates that Lafora bodies are also present in astrocytes. To define the role of astrocytic Lafora bodies in Lafora disease pathology, we deleted glycogen synthase specifically from astrocytes in a mouse model of the disease (malinKO). Strikingly, blocking glycogen synthesis in astrocytes—thus impeding Lafora bodies accumulation in this cell type—prevented the increase in neurodegeneration markers, autophagy impairment, and metabolic changes characteristic of the malinKO model. Conversely, mice that overaccumulate glycogen in astrocytes showed an increase in these markers. These results unveil the deleterious consequences of the deregulation of glycogen metabolism in astrocytes and change the perspective that Lafora disease is caused solely by alterations in neurons.

Supplementation of a propionate-producing consortium improves markers of insulin resistance in an in vitro model of gut-liver axis

2020 ◽  
Vol 318 (5) ◽  
pp. E742-E749 ◽  
Author(s):  
Racha El Hage ◽  
Emma Hernandez-Sanabria ◽  
Marta Calatayud Arroyo ◽  
Tom Van de Wiele
Keyword(s):  
Insulin Resistance ◽  
Cross Talk ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Glycogen Synthesis ◽  
Short Chain Fatty Acids ◽  
Glycogen Storage ◽  
Cellular Level ◽  
Low Grade

Gut-liver cross talk is an important determinant of human health with profound effects on energy homeostasis. While gut microbes produce a huge range of metabolites, specific compounds such as short-chain fatty acids (SCFAs) can enter the portal circulation and reach the liver (Brandl K, Schnabl B. Curr Opin Gastroenterol 33: 128–133, 2017), a central organ involved in glucose homeostasis and diabetes control. Propionate is a major SCFA involved in activation of intestinal gluconeogenesis (IGN), thereby regulating food intake, enhancing insulin sensitivity, and leading to metabolic homeostasis. Although microbiome-modulating strategies may target the increased microbial production of propionate, it is not clear whether such an effect spreads through to the hepatic cellular level. Here, we designed a propionate-producing consortium using a selection of commensal gut bacteria, and we investigated how their delivered metabolites impact an in vitro enterohepatic model of insulin resistance. Glycogen storage on hepatocyte-like cells and inflammatory markers associated with insulin resistance were evaluated to understand the role of gut metabolites on gut-liver cross talk in a simulated scenario of insulin resistance. The metabolites produced by our consortium increased glycogen synthesis by ~57% and decreased proinflammatory markers such as IL-8 by 12%, thus elucidating the positive effect of our consortium on metabolic function and low-grade inflammation. Our results suggest that microbiota-derived products can be a promising multipurpose strategy to modulate energy homeostasis, with the potential ability to assist in managing metabolic diseases due to their adaptability.

scholarly journals Deficiency of the E3 Ubiquitin Ligase RBCK1 Causes Diffuse Brain Polyglucosan Accumulation and Neurodegeneration

2018 ◽  
Author(s):  
Mitchell A. Sullivan ◽  
Felix Nitschke ◽  
Erin E. Chown ◽  
Laura F. DiGiovanni ◽  
Mackenzie Chown ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Glycogen Synthase ◽  
Glycogen Synthesis ◽  
E3 Ubiquitin Ligase ◽  
Branching Enzyme ◽  
Lafora Disease ◽  
Ubiquitin Chain ◽  
Polyglucosan Bodies ◽  
Muscle Tissues ◽  
Neurobehavioral Deficits

SUMMARYGlycogen synthesis is vital, malstructure resulting in precipitation and accumulation into neurotoxic polyglucosan bodies (PBs). One well-understood mechanism of PB generation is glycogen branching enzyme deficiency (GBED). Less understood is Lafora disease (LD), resulting from absence of the glycogen phosphatase laforin or the E3 ubiquitin ligase malin, and accumulation of hyperphosphorylated PBs. LD afforded first insight that glycogen sphericity depends on more than adequate branching activity. Unexpectedly, deficiencies of the Linear Ubiquitin Chain Assembly Complex (LUBAC) components RBCK1 and HOIP result in PBs in muscle tissues. Here we analyzed nervous system phenotypes of mice lacking RBCK1 and find profuse PB accumulations in brain and spinal cord with extensive neurodegeneration and neurobehavioral deficits. Brain glycogen in these mice is characterized by long chains and hyperphosphorylation, similar to LD. Like in LD, glycogen synthase and branching enzyme are unaltered. Regional PB distribution mirrors LD and not GBED. Perisynaptic PB localization is unlike LD or GBED. The results indicate that RBCK1 is part of a system supplementing laforin-malin in regulating glycogen architecture including in unique neuronal locales.

scholarly journals Generation and characterization of a laforin nanobody inhibitor

2021 ◽  
Author(s):  
Zoe R. Simmons ◽  
Savita Sharma ◽  
Jeremiah Wayne ◽  
Sheng Li ◽  
Craig W. Vander Kooi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Glycogen Metabolism ◽  
Childhood Epilepsy ◽  
Hydrogen Deuterium Exchange ◽  
Lafora Disease ◽  
Gene Encoding ◽  
Lafora Bodies ◽  
Hydrogen Deuterium

AbstractMutations in the gene encoding the glycogen phosphatase laforin result in the fatal childhood epilepsy Lafora disease (LD). A cellular hallmark of LD is cytoplasmic, hyper-phosphorylated, glycogen-like aggregates called Lafora bodies (LBs) that form in nearly all tissues and drive disease progression. Additional tools are needed to define the cellular function of laforin, understand the pathological role of laforin in LD, and determine the role of glycogen phosphate in glycogen metabolism. We present the generation and characterization of laforin nanobodies. We identify multiple classes of specific laforin-binding nanobodies and determine their binding epitopes using hydrogen deuterium exchange (HDX) mass spectrometry. Further, one family of nanobodies is identified that serves as an inhibitor of laforin catalytic activity. The laforin nanobodies are an important set of tools that open new avenues to define unresolved questions.

scholarly journals Lafora Disease: A Review of Molecular Mechanisms and Pathology

2018 ◽  
Vol 49 (06) ◽  
pp. 357-362 ◽  
Author(s):  
Brandy Verhalen ◽  
Susan Arnold ◽  
Berge Minassian
Keyword(s):  
Ubiquitin Ligase ◽  
Molecular Mechanisms ◽  
Neurodegenerative Disorder ◽  
Vegetative State ◽  
Glycogen Synthesis ◽  
Loss Of Function ◽  
Lafora Disease ◽  
Lafora Bodies ◽  
Progressive Myoclonus Epilepsy ◽  
Myoclonus Epilepsy

AbstractLafora's disease is a neurodegenerative disorder caused by recessive loss-of-function mutations in the EPM2A (laforin glycogen phosphatase) or EPM2B (malin E3 ubiquitin ligase) genes. Neuropathology is characterized by malformed precipitated glycogen aggregates termed Lafora bodies. Asymptomatic until adolescence, patients undergo first insidious then rapid progressive myoclonus epilepsy toward a vegetative state and death within a decade. Laforin and malin interact to regulate glycogen phosphorylation and chain length pattern, the latter critical to glycogen's solubility. Significant gaps remain in precise mechanistic understanding. However, demonstration that partial reduction in brain glycogen synthesis near-completely prevents the disease in its genetic animal models opens a direct present path to therapy.

scholarly journals Targeting Pathogenic Lafora Bodies in Lafora Disease Using an Antibody-Enzyme Fusion

2019 ◽  
Vol 30 (4) ◽  
pp. 689-705.e6 ◽  
Author(s):  
M. Kathryn Brewer ◽  
Annette Uittenbogaard ◽  
Grant L. Austin ◽  
Dyann M. Segvich ◽  
Anna DePaoli-Roach ◽  
...  
Keyword(s):  
Lafora Disease ◽  
Lafora Bodies ◽  
Enzyme Fusion

scholarly journals Canine Lafora Disease: An Unstable Repeat Expansion Disorder

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 689
Author(s):  
Thilo von Klopmann ◽  
Saija Ahonen ◽  
Irene Espadas-Santiuste ◽  
Kaspar Matiasek ◽  
Daniel Sanchez-Masian ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Vision Loss ◽  
Clinical Signs ◽  
Myotendinous Junction ◽  
Homozygous Mutation ◽  
Loss Of Function ◽  
Lafora Disease ◽  
Polyglucosan Bodies ◽  
Lafora Bodies ◽  
Mixed Breed

Canine Lafora disease is a recessively inherited, rapidly progressing neurodegenerative disease caused by the accumulation of abnormally constructed insoluble glycogen Lafora bodies in the brain and other tissues due to the loss of NHL repeat containing E3 ubiquitin protein ligase 1 (NHLRC1). Dogs have a dodecamer repeat sequence within the NHLRC1 gene, which is prone to unstable (dynamic) expansion and loss of function. Progressive signs of Lafora disease include hypnic jerks, reflex and spontaneous myoclonus, seizures, vision loss, ataxia and decreased cognitive function. We studied five dogs (one Chihuahua, two French Bulldogs, one Griffon Bruxellois, one mixed breed) with clinical signs associated with canine Lafora disease. Identification of polyglucosan bodies (Lafora bodies) in myocytes supported diagnosis in the French Bulldogs; muscle areas close to the myotendinous junction and the myofascial union segment had the highest yield of inclusions. Postmortem examination of one of the French Bulldogs revealed brain Lafora bodies. Genetic testing for the known canine NHLRC1 mutation confirmed the presence of a homozygous mutation associated with canine Lafora disease. Our results show that Lafora disease extends beyond previous known breeds to the French Bulldog, Griffon Bruxellois and even mixed-breed dogs, emphasizing the likely species-wide nature of this genetic problem. It also establishes these breeds as animal models for the devastating human disease. Genetic testing should be used when designing breeding strategies to determine the frequency of the NHLRC1 mutation in affected breeds. Lafora diseases should be suspected in any older dog presenting with myoclonus, hypnic jerks or photoconvulsions.

ÉTUDE IN VITRO DU MÉTABOLISME DES HYDRATES DE CARBONE DANS LE LEUCOCYTE CIRCULANT DU COBAYE TRAITÉ À LA CORTISONE

1966 ◽  
Vol 51 (2) ◽  
pp. 193-202
Author(s):  
J. A. Antonioli ◽  
A. Vannotti
Keyword(s):  
Glucose Concentration ◽  
Intramuscular Injection ◽  
Acute Inflammation ◽  
Glycogen Content ◽  
Glycogen Synthesis ◽  
Lactate Production ◽  
Glucose Consumption ◽  
List Type ◽  
Hydrates De Carbone

ABSTRACT 1. The metabolism of suspensions of circulating leucocytes has been studied after intramuscular injection of a dose of 50 mg/kg of a corticosteroid (cortisone acetate). The suspensions were incubated under aerobic conditions in the presence of a glucose concentration of 5.6 mm. Glucose consumption, lactate production, and variations in intracellular glycogen concentration were measured. After the administration of the corticosteroid, the anabolic processes of granulocyte metabolism were reversibly stimulated. Glucose consumption and lactate production increased 12 hours after the injection, but tended to normalize after 24 hours. The glycogen content of the granulocytes was enhanced, and glycogen synthesis during the course of the incubation was greatly stimulated. The action of the administered corticosteroid is more prolonged in females than in males. The injection of the corticosteroid caused metabolic modifications which resemble in their modulations and in their chronological development those found in circulating granulocytes of guinea-pigs suffering from sterile peritonitis. These results suggest, therefore, that, in the case of acute inflammation, the glucocorticosteroids may play an important role in the regulation of the metabolism of the blood leucocytes.

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