Uptake and processing of glycoproteins by rat hepatic mannose receptor

1987 ◽  
Vol 252 (5) ◽  
pp. E690-E698 ◽  
Author(s):  
M. E. Taylor ◽  
M. S. Leaning ◽  
J. A. Summerfield
Keyword(s):  
Intracellular Transport ◽  
Compartmental Model ◽  
Mannose Receptor ◽  
Structural Features ◽  
Hepatic Uptake ◽  
The Other ◽  
Lysosomal Storage ◽  
Sinusoidal Cells ◽  
Enzyme Replacement

A linear compartmental model has been developed for the in vivo metabolism of glycoproteins. The model is applied to the interpretation of dynamic data from the rat on agalactoorosomucoid (AGOR), an N-acetylglucosamine (GlcNAc-)-terminated glycoprotein, and three neoglycoproteins terminating in mannose [mannose36-bovine serum albumin (Man-BSA)] or glucose [maltose29-BSA (Mal29-BSA) and maltose8-BSA (Mal8-BSA)]. All of these proteins are taken up by the Man/GlcNAc receptor on hepatic sinusoidal cells. The rate of uptake was found to be determined by sugar type (Man-BSA, 0.78 min-1 greater than Mal29-BSA, 0.13 min-1), sugar density (Mal29-BSA greater than Mal8-BSA), and the geometry of the sugar display (AGOR, 0.51 min-1 greater than Mal29-BSA). Intracellular transport from the cell membrane to the lysosomes was slower for Man-BSA (approximately 3 min) than for the other ligands (approximately 0 min), suggesting that receptor-ligand uncoupling was slower for Man-BSA for which the receptor had the highest affinity or that extralysosomal catabolism of the other ligands occurred. Catabolism was also determined by the carbohydrate moiety of the ligand; it was greater for Mal29-BSA and Mal8-BSA (greater than or equal to 0.8 min-1) than for Man-BSA (0.27 min-1), and AGOR, with a complex oligosaccharide, was most resistant to degradation (0.14 min-1). An understanding of these structural features of glycoproteins that influence hepatic uptake, transport, and catabolism will be of value in drug targeting and for enzyme replacement in lysosomal storage disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

A Comparison of the Pharmacological Properties of Carbohydrate Remodeled Recombinant and Placental-Derived β-Glucocerebrosidase: Implications for Clinical Efficacy in Treatment of Gaucher Disease

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 2807-2816 ◽  
Author(s):  
BethAnn Friedman ◽  
Kris Vaddi ◽  
Constance Preston ◽  
Elizabeth Mahon ◽  
James R. Cataldo ◽  
...  
Keyword(s):  
Gaucher Disease ◽  
Dissociation Constants ◽  
Mannose Receptor ◽  
Pharmacological Properties ◽  
Enzyme Replacement ◽  
Macrophage Mannose Receptor ◽  
Binding Data ◽  
Parenchymal Cells ◽  
Mannose Receptors

The objective of these studies was to characterize the macrophage mannose receptor binding and pharmacological properties of carbohydrate remodeled human placental-derived and recombinant β-glucocerebrosidase (pGCR and rGCR, respectively). These are similar but not identical molecules that were developed as enzyme replacement therapies for Gaucher disease. Both undergo oligosaccharide remodeling during purification to expose terminal mannose sugar residues. Competitive binding data indicated carbohydrate remodeling improved targeting to mannose receptors over native enzyme by two orders of magnitude. Mannose receptor dissociation constants (Kd) for pGCR and rGCR were each 13 nmol/L. At 37°C, 95% of the total macrophage binding was mannose receptor specific. In vivo, pGCR and rGCR were cleared from circulation by a saturable pathway. The serum half-life (t1/2) was 3 minutes when less than saturable amounts were injected intravenously (IV) into mice. Twenty minutes postdose, β-glucocerebrosidase activity increased over endogenous levels in all tissues examined. Fifty percent of the injected activity was recovered. Ninety-five percent of recovered activity was in the liver. Parenchymal cells (PC), Kupffer cells (KC), and liver endothelium cells (LEC) were responsible for 75%, 22%, and 3%, respectively, of the hepatocellular uptake of rGCR and for 76%, 11%, and 12%, respectively, of the hepatocellular uptake of pGCR. Both molecules had poor stability in LEC and relatively long terminal half-lives in PC (t1/2 = 2 days) and KC (t1/2 = 3 days).

scholarly journals Glucagon receptors in endothelial and Kupffer cells of mouse liver.

1988 ◽  
Vol 36 (9) ◽  
pp. 1081-1089 ◽  
Author(s):  
J Watanabe ◽  
K Kanai ◽  
S Kanamura
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Kupffer Cells ◽  
Mouse Liver ◽  
Intracellular Transport ◽  
Coated Pits ◽  
Sinusoidal Cells ◽  
Nonparenchymal Cells ◽  
Glucagon Receptors

To determine whether hepatic sinusoidal cells contain glucagon receptors and, if so, to study the significance of the receptors in the cells, binding of [125I]-glucagon to nonparenchymal cells (mainly endothelial cells and Kupffer cells) isolated from mouse liver was examined by quantitative autoradiography and biochemical methods. Furthermore, the pathway of intracellular transport of colloidal gold-labeled glucagon (AuG) was examined in vivo. Autoradiographic and biochemical results demonstrated many glucagon receptors in both endothelial cells and Kupffer cells, and more receptors being present in endothelial cells than in Kupffer cells. In vivo, endothelial cells internalized AuG particles into coated vesicles via coated pits and transported the particles to endosomes, lysosomes, and abluminal plasma membrane. Therefore, receptor-mediated transcytosis of AuG occurs in endothelial cells. The number of particles present on the abluminal plasma membrane was constant if the amount of injected AuG increased. Therefore, the magnitude of receptor-mediated transcytosis of AuG appears to be regulated by endothelial cells. Kupffer cells internalized the ligand into cytoplasmic tubular structures via plasma membrane invaginations and transported the ligand exclusively to endosomes and lysosomes, suggesting that the ligand is degraded by Kupffer cells.

scholarly journals Role of transferrin in determining internal iron distribution

Blood ◽  
1977 ◽  
Vol 49 (6) ◽  
pp. 957-966
Author(s):  
P Pootrakul ◽  
A Christensen ◽  
B Josephson ◽  
CA Finch
Keyword(s):  
Isotope Ratio ◽  
Hepatic Uptake ◽  
The Other ◽  
Iron Salts ◽  
Iron Deficient ◽  
Loading And Unloading ◽  
The Mean

The behavior in vivo of transferrin in loading and unloading iron from its two sites was examined in rats. Radioiron entering the plasma from the gastrointestinal tract in iron-deficient, normal and iron-loaded rats did not differ in its subsequent tissue distribution between erythroid marrow and liver of normal recipients from a second isotope added to the same plasma in vitro. Loading studies in vitro were then carried out employing a reticulocyte incubation model designed to place one isotope predominantly on one site of transferrin, more available to the erythron, and the second isotope on the other site, more available to the liver. In 15 groups of animals in which 3 different iron salts were employed to load transferrin with iron, the mean isotope ratio in the erythron was 1.03 (+/-0.06 SD) and the mean liver ratio was 0.75 (+/-0.21 SD). It was found that the incubation of plasma with reticulocytes resulted in contamination of the plasma by radioactive hemoglobin. After allowance was made for hepatic uptake of radiohemoglobin in the 13 groups in which proper correction could be made, the isotope ratio in the liver became 0.97 (+/-0.17 SD). It is concluded that iron atoms from the two sites of transferrin have similar tissue distributions in vivo in the experimental situations examined.

scholarly journals The usage of enzyme replacement treatments, economic burden, and quality of life of patients with four lysosomal storage diseases in Shanghai, China

2021 ◽  
Author(s):  
Jiahao Hu ◽  
Lin Zhu ◽  
Jiangjiang He ◽  
Dingguo Li ◽  
Huiwen Zhang ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Economic Burden ◽  
Gaucher Disease ◽  
Lysosomal Storage Diseases ◽  
The Other ◽  
Lysosomal Storage ◽  
Total Health Expenditure ◽  
Enzyme Replacement ◽  
Reimbursement Level

Abstract Background Lysosomal storage diseases (LSDs) are a group of rare diseases that caused progressive physical dysfunction and organ failure, which significantly affected patients’ quality of life. Enzyme replacement treatments (ERTs) are now acknowledged as the advanced therapies for LSDs while cost millions per patient per year. Previous studies seldom reported the usage of ERTs and disease burden of patients with LSDs in China. The objective of this study was to explore the characteristics and usage of ERTs of patients with the four different LSDs (Gaucher, Fabry, Pompe disease and Mucopolysaccharidosis) in Shanghai and then evaluate the economic burden and quality of life of these patients. Methods The study used data extracted from a large survey of living conditions of patients with rare diseases in Shanghai, which was conducted from April to August 2020. A total of 31patients, involving 5, 14, 4 and 8 patients with Gaucher, Fabry, Pompe disease and Mucopolysaccharidosis, respectively, was included in analysis. Descriptive statistics was used to describe the socio-demographic information (age, gender, education and etc.), economic burden caused by LSDs (direct medical and non-medical costs, and indirect cost in 2019), the treatment (usage of drugs) and the patients’ quality of life. Results Five Gaucher disease patients in Shanghai used Imiglucerase in 2019, while the other 26 patients with the other three LSDs didn’t receive ERTs. The total health expenditure of Gaucher disease patients was 2,273,000CNY on average mainly resulted by the high cost of Imiglucerase. The total health expenditure of the other 26 patients was 37,765CNY on average. The average total disease burdens of Gaucher disease patients and the patients with the other three LSDs were 164,301CNY and 58,352CNY, respectively. The mean EQ-VAS score of GD patients was 76.4 ± 15.5, which was higher than that of the other three LSDs. All the patients with LSDs in this study reported poor quality of life, which was significantly worse than the Chinese general population. Conclusion Few patients with LSDs in Shanghai could have access to available ERTs without a high reimbursement level. Though the cost-sharing mechanism of basic medical insurance, charity fund and patients had been explored for Gaucher disease in Shanghai, the Out-of-pocket part still laid a heavy economic burden on the patients and their families. The scope of drug reimbursement list and the reimbursement level should be further expanded and raised to help improve the quality of life of patients with LSDs.

scholarly journals Targeting Brain Disease in MPSII: Preclinical Evaluation of IDS-Loaded PLGA Nanoparticles

2019 ◽  
Vol 20 (8) ◽  
pp. 2014 ◽  
Author(s):  
Laura Rigon ◽  
Marika Salvalaio ◽  
Francesca Pederzoli ◽  
Elisa Legnini ◽  
Jason Thomas Duskey ◽  
...  
Keyword(s):  
Polymeric Nanoparticles ◽  
Plga Nanoparticles ◽  
Neurological Involvement ◽  
Lysosomal Storage ◽  
Enzyme Replacement ◽  
Organ Systems ◽  
General Improvement ◽  
The One ◽  
The Brain

Mucopolysaccharidosis type II (MPSII) is a lysosomal storage disorder due to the deficit of the enzyme iduronate 2-sulfatase (IDS), which leads to the accumulation of glycosaminoglycans in most organ-systems, including the brain, and resulting in neurological involvement in about two-thirds of the patients. The main treatment is represented by a weekly infusion of the functional enzyme, which cannot cross the blood-brain barrier and reach the central nervous system. In this study, a tailored nanomedicine approach based on brain-targeted polymeric nanoparticles (g7-NPs), loaded with the therapeutic enzyme, was exploited. Fibroblasts from MPSII patients were treated for 7 days with NPs loaded with the IDS enzyme; an induced IDS activity like the one detected in healthy cells was measured, together with a reduction of GAG content to non-pathological levels. An in vivo short-term study in MPSII mice was performed by weekly administration of g7-NPs-IDS. Biochemical, histological, and immunohistochemical evaluations of liver and brain were performed. The 6-weeks treatment produced a significant reduction of GAG deposits in liver and brain tissues, as well as a reduction of some neurological and inflammatory markers (i.e., LAMP2, CD68, GFAP), highlighting a general improvement of the brain pathology. The g7-NPs-IDS approach allowed a brain-targeted enzyme replacement therapy. Based on these positive results, the future aim will be to optimize NP formulation further to gain a higher efficacy of the proposed approach.

scholarly journals Transient Production of Human β-Glucocerebrosidase With Mannosidic-Type N-Glycan Structure in Glycoengineered Nicotiana benthamiana Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Naphatsamon Uthailak ◽  
Hiroyuki Kajiura ◽  
Ryo Misaki ◽  
Kazuhito Fujiyama
Keyword(s):  
Enzyme Activity ◽  
Nicotiana Benthamiana ◽  
Gaucher Disease ◽  
Mannose Receptor ◽  
Glycan Structure ◽  
Lysosomal Storage ◽  
Promising Alternative ◽  
Enzyme Replacement ◽  
Therapeutic Uses ◽  
Glycosylation Sites

Gaucher disease is an inherited lysosomal storage disorder caused by a deficiency of functional enzyme β-glucocerebrosidase (GCase). Recombinant GCase has been used in enzyme replacement therapy to treat Gaucher disease. Importantly, the terminal mannose N-glycan structure is essential for the uptake of recombinant GCase into macrophages via the mannose receptor. In this research, recombinant GCase was produced using Agrobacterium-mediated transient expression in both wild-type (WT) and N-acetylglucosaminyltransferase I (GnTI) downregulated Nicotiana benthamiana (ΔgntI) plants, the latter of which accumulates mannosidic-type N-glycan structures. The successfully produced functional GCase exhibited GCase enzyme activity. The enzyme activity was the same as that of the conventional mammalian-derived GCase. Notably, N-glycan analysis revealed that a mannosidic-type N-glycan structure lacking plant-specific N-glycans (β1,2-xylose and α1,3-fucose residues) was predominant in all glycosylation sites of purified GCase produced from ΔgntI plants. Our research provides a promising alternative plant line as a host for the production of recombinant GCase with a mannosidic-type N-glycan structure. This glycoengineered plant might be applicable to the production of other pharmaceutical proteins, especially mannose receptor targeted protein, for therapeutic uses.

scholarly journals Uptake of injected 125I-ricin by rat liver in vivo. Subcellular distribution and characterization of the internalized ligand

1992 ◽  
Vol 284 (1) ◽  
pp. 249-257 ◽  
Author(s):  
J P Frénoy ◽  
E Turpin ◽  
M Janicot ◽  
F Gehin-Fouque ◽  
B Desbuquois
Keyword(s):  
Molecular Mass ◽  
Rat Liver ◽  
Mannose Receptor ◽  
Subcellular Fractionation ◽  
Hepatic Uptake ◽  
Endocytic Pathway ◽  
Time Dependent ◽  
Disulphide Bridge ◽  
P Fraction

Subcellular-fractionation techniques were used to characterize the endocytic pathway followed by ricin in rat liver in vivo and tentatively identify the site(s) at which the ricin interchain disulphide bridge is split. After injection of 125I-ricin, hepatic uptake of radioactivity was maximum at 30 min (40% of injected dose). At 5 min, about 80% of the radioactivity in the homogenate was recovered in the microsomal (P) fraction, but later on the recovery of the radioactivity in the mitochondrial-lysosomal (ML) fractions progressively increased (50% at 30 min) at the expense of that in the P fraction. Subfractionation of the P and ML fractions on analytical sucrose-density gradients revealed a time-dependent translocation of the radioactivity from low- to high-density endocytic structures, with median relative densities at 5 and 60 min of about 1.15 and 1.16 (P fraction) and 1.19 and 1.22 (ML fraction) respectively. The late distribution of the radioactivity in the ML fraction was similar to that of the lysosomal marker acid phosphatase. Studies with co-injected lactose and mannan showed that ricin was internalized mainly via the mannose receptor. In the presence of mannan, the late recovery of radioactivity in the ML fraction was decreased, and the distribution of the radioactivity associated with the P fraction was shifted toward lower densities (median relative density 1.13), indicating a different pathway of endocytosis. Analysis of the radioactivity associated with the ML and S fractions by SDS/PAGE revealed a time-dependent increase in the amount of intact A- and B-chains and low-molecular-mass products. When ML fractions containing partially processed ricin were incubated at 37 degrees C at pH 5 or at pH 7.2 in the presence of ATP, only low-molecular-mass products were generated. We conclude that internalized ricin associates with endocytic structures whose size and density of equilibration increase with time, and that, although detectable in these structures, reduction of the ricin interchain disulphide bridge occurs to a large extent in the cytosol.

scholarly journals Exploiting the Potential of Drosophila Models in Lysosomal Storage Disorders: Pathological Mechanisms and Drug Discovery

Biomedicines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 268
Author(s):  
Laura Rigon ◽  
Concetta De Filippis ◽  
Barbara Napoli ◽  
Rosella Tomanin ◽  
Genny Orso
Keyword(s):  
Negative Impact ◽  
Drug Repurposing ◽  
Lysosomal Storage Disorders ◽  
Neurological Involvement ◽  
Lysosomal Storage ◽  
Recombinant Enzymes ◽  
Enzyme Replacement ◽  
Storage Disorders ◽  
Drosophila Models

Lysosomal storage disorders (LSDs) represent a complex and heterogeneous group of rare genetic diseases due to mutations in genes coding for lysosomal enzymes, membrane proteins or transporters. This leads to the accumulation of undegraded materials within lysosomes and a broad range of severe clinical features, often including the impairment of central nervous system (CNS). When available, enzyme replacement therapy slows the disease progression although it is not curative; also, most recombinant enzymes cannot cross the blood-brain barrier, leaving the CNS untreated. The inefficient degradative capability of the lysosomes has a negative impact on the flux through the endolysosomal and autophagic pathways; therefore, dysregulation of these pathways is increasingly emerging as a relevant disease mechanism in LSDs. In the last twenty years, different LSD Drosophila models have been generated, mainly for diseases presenting with neurological involvement. The fruit fly provides a large selection of tools to investigate lysosomes, autophagy and endocytic pathways in vivo, as well as to analyse neuronal and glial cells. The possibility to use Drosophila in drug repurposing and discovery makes it an attractive model for LSDs lacking effective therapies. Here, ee describe the major cellular pathways implicated in LSDs pathogenesis, the approaches available for their study and the Drosophila models developed for these diseases. Finally, we highlight a possible use of LSDs Drosophila models for drug screening studies.

scholarly journals Role of transferrin in determining internal iron distribution

Blood ◽  
1977 ◽  
Vol 49 (6) ◽  
pp. 957-966 ◽  
Author(s):  
P Pootrakul ◽  
A Christensen ◽  
B Josephson ◽  
CA Finch
Keyword(s):  
Isotope Ratio ◽  
Hepatic Uptake ◽  
The Other ◽  
Iron Salts ◽  
Iron Deficient ◽  
Loading And Unloading ◽  
The Mean

Abstract The behavior in vivo of transferrin in loading and unloading iron from its two sites was examined in rats. Radioiron entering the plasma from the gastrointestinal tract in iron-deficient, normal and iron-loaded rats did not differ in its subsequent tissue distribution between erythroid marrow and liver of normal recipients from a second isotope added to the same plasma in vitro. Loading studies in vitro were then carried out employing a reticulocyte incubation model designed to place one isotope predominantly on one site of transferrin, more available to the erythron, and the second isotope on the other site, more available to the liver. In 15 groups of animals in which 3 different iron salts were employed to load transferrin with iron, the mean isotope ratio in the erythron was 1.03 (+/-0.06 SD) and the mean liver ratio was 0.75 (+/-0.21 SD). It was found that the incubation of plasma with reticulocytes resulted in contamination of the plasma by radioactive hemoglobin. After allowance was made for hepatic uptake of radiohemoglobin in the 13 groups in which proper correction could be made, the isotope ratio in the liver became 0.97 (+/-0.17 SD). It is concluded that iron atoms from the two sites of transferrin have similar tissue distributions in vivo in the experimental situations examined.

Opening New Horizons in the Treatment of Childhood Onset Leukodystrophies

2019 ◽  
Vol 50 (04) ◽  
pp. 211-218 ◽  
Author(s):  
Stina Schiller ◽  
Marco Henneke ◽  
Jutta Gärtner
Keyword(s):  
Early Stage ◽  
Treatment Options ◽  
Clinical Signs ◽  
Disease Genes ◽  
Lysosomal Storage ◽  
Peroxisomal Disorders ◽  
Enzyme Replacement ◽  
Number Of Patients

AbstractLeukodystrophies (LDs) predominantly affect the white matter of the central nervous system and its main component, the myelin. The majority of LDs manifests in infancy with progressive neurodegeneration. Main clinical signs are intellectual and motor function losses of already attained developmental skills. Classical LDs include lysosomal storage disorders like metachromatic leukodystrophy (MLD), peroxisomal disorders like X-linked adrenoleukodystrophy (X-ALD), disorders of mitochondrial dysfunction, and myelin protein defects like Pelizaeus-Merzbacher disease. So far, there are only single LD disorders with effective treatment options in an early stage of disease. The increasing number of patients diagnosed with LDs emphasizes the need for novel therapeutic options. Impressive advances in biotechnology have not only led to the continuous identification of new disease genes for so far unknown LDs but also led to new effective neuroprotective and disease-modifying therapeutic approaches. This review summarizes ongoing and novel innovative treatment options for LD patients and their challenges. It includes in vitro and in vivo approaches with focus on stem cell and gene therapies, intrathecal substrate or enzyme replacement, and genome editing.

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