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Bakrania A, Mo Y, Zheng G, Bhat M. RNA nanomedicine in liver diseases. Hepatology 2024:01515467-990000000-00569. [PMID: 37725757 DOI: 10.1097/hep.0000000000000606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/08/2023] [Indexed: 09/21/2023]
Abstract
The remarkable impact of RNA nanomedicine during the COVID-19 pandemic has demonstrated the expansive therapeutic potential of this field in diverse disease contexts. In recent years, RNA nanomedicine targeting the liver has been paradigm-shifting in the management of metabolic diseases such as hyperoxaluria and amyloidosis. RNA nanomedicine has significant potential in the management of liver diseases, where optimal management would benefit from targeted delivery, doses titrated to liver metabolism, and personalized therapy based on the specific site of interest. In this review, we discuss in-depth the different types of RNA and nanocarriers used for liver targeting along with their specific applications in metabolic dysfunction-associated steatotic liver disease, liver fibrosis, and liver cancers. We further highlight the strategies for cell-specific delivery and future perspectives in this field of research with the emergence of small activating RNA, circular RNA, and RNA base editing approaches.
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Affiliation(s)
- Anita Bakrania
- Department of Medicine, Toronto General Hospital Research Institute, Toronto, Ontario, Canada
- Department of Medicine, Ajmera Transplant Program, University Health Network, Toronto, Ontario, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Yulin Mo
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Gang Zheng
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Mamatha Bhat
- Department of Medicine, Toronto General Hospital Research Institute, Toronto, Ontario, Canada
- Department of Medicine, Ajmera Transplant Program, University Health Network, Toronto, Ontario, Canada
- Department of Medicine, Division of Gastroenterology, University Health Network and University of Toronto, Toronto, Ontario, Canada
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Zenze M, Singh M. Receptor Targeting Using Copolymer-Modified Gold Nanoparticles for pCMV-Luc Gene Delivery to Liver Cancer Cells In Vitro. Int J Mol Sci 2024; 25:5016. [PMID: 38732235 PMCID: PMC11084699 DOI: 10.3390/ijms25095016] [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: 04/15/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/13/2024] Open
Abstract
The formulation of novel delivery protocols for the targeted delivery of genes into hepatocytes by receptor mediation is important for the treatment of liver-specific disorders, including cancer. Non-viral delivery methods have been extensively studied for gene therapy. Gold nanoparticles (AuNPs) have gained attention in nanomedicine due to their biocompatibility. In this study, AuNPs were synthesized and coated with polymers: chitosan (CS), and polyethylene glycol (PEG). The targeting moiety, lactobionic acid (LA), was added for hepatocyte-specific delivery. Physicochemical characterization revealed that all nano-formulations were spherical and monodispersed, with hydrodynamic sizes between 70 and 250 nm. Nanocomplexes with pCMV-Luc DNA (pDNA) confirmed that the NPs could bind, compact, and protect the pDNA from nuclease degradation. Cytotoxicity studies revealed that the AuNPs were well tolerated (cell viabilities > 70%) in human hepatocellular carcinoma (HepG2), embryonic kidney (HEK293), and colorectal adenocarcinoma (Caco-2) cells, with enhanced transgene activity in all cells. The inclusion of LA in the NP formulation was notable in the HepG2 cells, which overexpress the asialoglycoprotein receptor on their cell surface. A five-fold increase in luciferase gene expression was evident for the LA-targeted AuNPs compared to the non-targeted AuNPs. These AuNPs have shown potential as safe and suitable targeted delivery vehicles for liver-directed gene therapy.
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Affiliation(s)
| | - Moganavelli Singh
- Nano-Gene and Drug Delivery Laboratory, Discipline of Biochemistry, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa;
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Naidoo S, Daniels A, Habib S, Singh M. Poly-L-Lysine-Lactobionic Acid-Capped Selenium Nanoparticles for Liver-Targeted Gene Delivery. Int J Mol Sci 2022; 23:ijms23031492. [PMID: 35163414 PMCID: PMC8835765 DOI: 10.3390/ijms23031492] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 02/04/2023] Open
Abstract
Liver cancer is currently regarded as the second leading cause of cancer-related mortality globally and is the sixth most diagnosed malignancy. Selenium nanoparticles (SeNPs) have attracted favorable attention as nanocarriers for gene therapy, as they possess beneficial antioxidant and anticancer properties. This study aimed to design, functionalize and characterize SeNPs to efficiently bind, protect and deliver pCMV-Luc DNA to hepatocellular carcinoma (HepG2) cells. The SeNPs were synthesized by ascorbic acid reduction and functionalized with poly-L-lysine (PLL) to stabilize and confer positive charges to the nanoparticles. The SeNPs were further decorated with lactobionic acid (LA) to target the asialoglycoprotein receptors abundantly expressed on the surface of the hepatocytes. All SeNPs were spherical, in the nanoscale range (<130 nm) and were capable of successfully binding, compacting and protecting the pDNA against nuclease degradation. The functionalized SeNP nanocomplexes exhibited minimal cytotoxicity (<30%) with enhanced transfection efficiency in the cell lines tested. Furthermore, the targeted SeNP (LA-PLL-SeNP) nanocomplex showed significant (* p < 0.05, ** p < 0.01, **** p < 0.0001) transgene expression in the HepG2 cells compared to the receptor-negative embryonic kidney (HEK293) cells, confirming receptor-mediated endocytosis. Overall, these functionalized SeNPs exhibit favorable features of suitable gene nanocarriers for the treatment of liver cancer.
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Smekalova EM, Kotelevtsev YV, Leboeuf D, Shcherbinina EY, Fefilova AS, Zatsepin TS, Koteliansky V. lncRNA in the liver: Prospects for fundamental research and therapy by RNA interference. Biochimie 2016; 131:159-172. [DOI: 10.1016/j.biochi.2016.06.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 06/14/2016] [Indexed: 12/19/2022]
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Witzigmann D, Quagliata L, Schenk SH, Quintavalle C, Terracciano LM, Huwyler J. Variable asialoglycoprotein receptor 1 expression in liver disease: Implications for therapeutic intervention. Hepatol Res 2016; 46:686-96. [PMID: 26422581 DOI: 10.1111/hepr.12599] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/07/2015] [Accepted: 09/19/2015] [Indexed: 02/08/2023]
Abstract
AIM One of the most promising strategies for the treatment of liver diseases is targeted drug delivery via the asialoglycoprotein receptor (ASGPR). The success of this approach heavily depends on the ASGPR expression level on parenchymal liver cells. In this study, we assessed the mRNA and protein expression levels of the major receptor subunit, ASGR1, in hepatocytes both in vitro and in vivo. METHODS In vitro, various liver cancer-derived cell lines were evaluated. In vivo, we screened the ASGR1 mRNA on 59 hepatocellular carcinoma and matched non-neoplastic tissue using RNA microarray. In addition, 350 human liver specimens of patients with hepatocellular carcinoma or non-neoplastic liver diseases were screened for ASGR1 protein level using tissue microarray analysis. RESULTS Our data reveal that the ASGR1 mRNA expression directly correlates with the protein level. We demonstrate that the ASGR1 expression is upregulated in cirrhotic specimens and is significantly decreased with increasing hepatocellular carcinoma grade. CONCLUSION Because the ASGR1 expression levels are variable between patients, our findings suggest that ASGPR-based targeting strategies should be combined with ASGPR-companion diagnostics to maximize clinical benefit.
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Affiliation(s)
- Dominik Witzigmann
- Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Luca Quagliata
- Institute of Pathology, Molecular Pathology Division, University Hospital of Basel, Basel, Switzerland
| | - Susanne H Schenk
- Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Cristina Quintavalle
- Institute of Pathology, Molecular Pathology Division, University Hospital of Basel, Basel, Switzerland
| | - Luigi M Terracciano
- Institute of Pathology, Molecular Pathology Division, University Hospital of Basel, Basel, Switzerland
| | - Jörg Huwyler
- Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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Singh A, Ariatti M, Singh M, Hawtrey A, Naidoo R. Biotin-directed assembly of targeted modular lipoplexes and their transfection of human hepatoma cells in vitro. Drug Deliv 2010; 17:426-33. [PMID: 20469969 DOI: 10.3109/10717541003777530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The asialoglycoprotein receptor, which is abundantly and near exclusively expressed on hepatocytes, has received much attention in the design of non-viral hepatotropic DNA delivery systems. Thus, asialoglycoproteins and hexopyranosyl ligands have been coupled to DNA-binding cationic polymers and liposomes in the assembly of complexes intended for uptake by liver parenchymal cells. The aim of the study was to construct a hepatocyte-targeted multimodular liposome-based transfecting complex, in which the biotin-streptavidin interaction provides the cohesive force between the ligand asialorosomucoid and the liposome bilayer, and to evaluate its transfection capabilities in the hepatocyte-derived human transformed cell line HepG2. Dibiotinylated asialoorosomucoid was attached to cationic liposomes constructed from 3beta[N-(N',N'-dimethylaminopropane)-carbamoyl] cholesterol (Chol-T):dioleoylphosphatidylethanolamine:biotinylcholesterylformylhydrazide (MSB1) (48:50:2 mole ratio) through streptavidin interposition. Liposome-pGL3 DNA interactions were studied by gel band shift and ethidium displacement assays. The cytotoxicity of assemblies was evaluated in the HepG2 cell line and transfection capabilities determined by measuring the activity of the transgene luciferase. Binding assays showed that all DNA was liposome associated at a DNA (negative):liposome (positive) charge ratio of 1:1. Accommodation of a streptavidin dibiotinylated asialoorosomucoid assembly was achieved at a DNA:liposome:streptavidin dibiotinylated asialoorosomucoid ratio of 1:4:9 (weight basis). Complexes showed optimal transfection activity at this ratio, which was reduced 10-fold by the presence of the competing ligand asialofetuin. The streptavidin-biotin interaction has been applied for the first time to the assembly of hepatocyte-targeted lipoplexes that display asialoorosomucoid and that are well tolerated by a human hepatoma cell line in which transfection is demonstrably achieved by receptor mediation. Favorable size and charge ratio characteristics suggest that this system may be suitable for in vivo application.
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Affiliation(s)
- Ashika Singh
- Pfizer Molecular Biology Research Facility, Nelson R Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
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Singh M, Ariatti M. Targeted gene delivery into HepG2 cells using complexes containing DNA, cationized asialoorosomucoid and activated cationic liposomes. J Control Release 2004; 92:383-94. [PMID: 14568419 DOI: 10.1016/s0168-3659(03)00360-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Unilamellar activated cationic liposomes containing 3beta[N-(N',N'-dimethylaminopropane)-carbamoyl] cholesterol, dioleoyl phosphatidylethanolamine (DOPE) and the N-hydroxysuccinimide ester of cholesteryl hemisuccinate (4:5:1, molar ratio) have been prepared and their DNA-binding capacity has been assessed in a gel retardation assay. Ternary complexes composed of activated cationic liposomes, carbodiimide-cationized asialoorosomucoid (Me+AOM) and pRSVL plasmid DNA were assembled for receptor-mediated DNA delivery into cells expressing the asialoglycoprotein receptor (ASGP-R). Binding of complexes in which Me+AOM was replaced by fluoresceinated Me+AOM (FMe+AOM) to the human hepatocellular cell line HepG2 at 4 degrees C was severely reduced by co-incubation with asialoorosomucoid (AOM). Moreover, assemblies containing liposomes, pRSVL DNA and Me+AOM (8:1:4, w/w/w) promoted high levels of luciferase activity in this cell line (1.3 x 10(7) relative light units/mg soluble cell protein). Assays conducted in the presence of a hundred-fold excess of the ligand AOM afforded considerably lower levels of transfection (2.5 x 10(5) relative light units/mg soluble cell protein). In contrast, the highest level of luciferase activity achieved with liposome, pRSVL DNA, AOM complexes was only a quarter of the best levels obtained with liposome, pRSVL DNA, Me+AOM assemblies. These findings strongly support the notion that complexes gain entry into hepatocyte-derived cells by ASGP-R mediation and that they are potentially useful gene carriers to liver hepatocytes.
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Affiliation(s)
- Moganavelli Singh
- Biochemistry, School of Biochemistry and Microbiology, Faculty of Science, University of Durban-Westville, Private Bag X54001, Durban, South Africa
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Singh M, Kisoon N, Ariatti M. Receptor-mediated gene delivery to HepG2 cells by ternary assemblies containing cationic liposomes and cationized asialoorosomucoid. Drug Deliv 2001; 8:29-34. [PMID: 11280441 DOI: 10.1080/107175401300002739] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
Unilamellar cationic liposomes have been prepared from an equimolar mixture of 3beta[N',N'-dimethylaminopropane)-carbomoyl] cholesterol (Chol-T), a higher homologue of 3beta[N',N'-dimethylaminoethane)-carbomoyl] cholesterol (DC-Chol), and dioleoylphosphatidyl-ethanolamine. The DNA binding capabilities of Chol-T and Chol-T/DOPE liposomes have been demonstrated in lipid impregnated paper-DNA binding assays and gel retardation experiments, respectively. These liposomes have been combined with pRSVL plasmid DNA and N-ethyl-N'-(3-trimethylpropylammonium) carbodiimide iodide modified asialoorosomucoid (Me+ CDI urea-AOM) to generate ternary electrostatic assemblies intended for selective entry into cells displaying the galactose-specific lectin. This effect has been evaluated in the human hepatocellular carcinoma cell line HepG2 in which high levels of luciferase activity were achieved (up to 1.84 x 10(7) relative light units/mg protein) after transfection with complexes containing liposomes (1-3 microg), Me+CDI urea-AOM (2 microg), and DNA (0.5 microg) in 0.5 mL culture medium. Transfections conducted in the presence of free asialoorosomucoid afforded much lower luciferase activity (up to 1.5 x 10(5) relative light units/mg protein) confirming that DNA uptake was predominantly via asialoorosomucoid receptor-mediated endocytosis. We concluded therefore that modular complexes used in our study display the carbohydrate moiety of the glycoprotein component prominently, thus permitting interaction of terminal galactose units with their cognate receptors on the cell membrane.
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Affiliation(s)
- M Singh
- School of Life and Environmental Sciences, University of Durban-Westville, South Africa
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Stefaner I, Klapper H, Sztul E, Fuchs R. Free-flow electrophoretic analysis of endosome subpopulations of rat hepatocytes. Electrophoresis 1997; 18:2516-22. [PMID: 9527479 DOI: 10.1002/elps.1150181405] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The separation of functional early and late endosomes from other cellular compartments by free-flow electrophoresis (FFE) has been previously demonstrated in nonpolarized cells. Here, using 125I-labeled anti-secretory component antibodies ([125I]SC Ab) and FITC-labeled asialoorosomucoid (FITC-ASOR) as markers of the transcytotic and lysosomal pathway, respectively, we demonstrate the separation of three distinct endosome subpopulations from polarized rat hepatocytes. Internalization of both markers at 16 degrees C resulted in their accumulation in a common endosome compartment, indicating that both the transcytotic and the lysosomal pathways are arrested in the sorting early endosome at temperatures below 20 degrees C. After chase of the markers from early endosomes into the transcytotic or the degradative route at 37 degrees C, transcytotic endosomes carrying [125I]SC Ab migrated with an electrophoretic motility between early and late endosomes while late endosomes labeled with FITC-ASOR were deflected more towards the anode than early endosomes. These data indicate that in rat hepatocytes, the transcytotic and lysosomal pathways utilize a common (i.e. early endosomes) and two distinct endosome subpopulations (i.e. transcytotic endosomes, late endosomes) prior to delivering proteins for biliary secretion or lysosomal degradation, respectively.
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Affiliation(s)
- I Stefaner
- Department of General and Experimental Pathology, University of Vienna, Austria
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Hara T, Aramaki Y, Takada S, Koike K, Tsuchiya S. Receptor-mediated transfer of pSV2CAT DNA to a human hepatoblastoma cell line HepG2 using asialofetuin-labeled cationic liposomes. Gene 1995; 159:167-74. [PMID: 7542617 DOI: 10.1016/0378-1119(95)00100-k] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Asialofetuin-labeled liposomes (AF-lps) were developed as a vector for gene transfer to hepatocytes. Plasmid pSV2CAT DNA which encodes bacterial chloramphenicol acetyltransferase (CAT) was associated with (meaning, in this report, the sum of 'to be adsorbed on the surface of' and 'to be encapsulated into the internal phase of') AF-lps (AF-lps-pSV2CAT) prepared by a tandem combination of the detergent removal and freeze-thaw methods. Ninety-six percent of input pSV2CAT was associated with AF-lps containing N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, and approx. two-thirds of the associated DNA was encapsulated into the internal phase. The uptake of AF-lps by the cultured human hepatoblastoma cell line HepG2, having asialoglycoprotein receptors (AGPR) on their plasma membrane, was decreased by the addition of free AF and cytochalasin B. AF-lps bound to HepG2 cells through specific interaction with AGPR, and were internalized into the cells by the receptor-mediated endocytotic pathway. HepG2 cells transfected by AF-lps-pSV2CAT showed a significantly higher CAT activity than those transfected by pSV2CAT associated with non-labeled control lps (N-lps-pSV2CAT) or a mixture of pSV2CAT and empty AF-lps. Pretreatment with EDTA-encapsulated AF-lps increased the transfection efficiency of AF-lps-pSV2CAT. The CAT activity in A431 and Swiss/3T3 cells transfected with AF-lps-pSV2CAT was low and almost the same as those transfected with N-lps-pSV2CAT. Since DNA encapsulated in lps is likely to be protected against digestion by nucleases in the blood circulation, AF-lps could be used as a gene transfer vector targeting the hepatocytes in vivo.
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Affiliation(s)
- T Hara
- Tokyo College of Pharmacy, Japan
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Paietta E. The nature and function of the Hodgkin's cell lectin and its role in lymphocyte agglutination. INTERNATIONAL REVIEW OF EXPERIMENTAL PATHOLOGY 1992; 33:115-40. [PMID: 1733869 DOI: 10.1016/b978-0-12-364933-1.50010-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- E Paietta
- Department of Oncology, Montefiore Medical Center, Bronx, New York
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12
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Puszkin S, Kohtz JD, Schook WJ, Kohtz DS. Clathrin-coated vesicle subtypes in mammalian brain tissue: detection of polypeptide heterogeneity by immunoprecipitation with monoclonal antibodies. J Neurochem 1989; 53:51-63. [PMID: 2656917 DOI: 10.1111/j.1471-4159.1989.tb07294.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A panel of monoclonal antibodies (mAbs) was developed to identify polypeptides sorted in subtypes of brain coated vesicles (CVs) and to separate these by immunoprecipitation. The corresponding antigen of some of the mAbs elicited by CV components was present also in synaptosomal plasma membrane, synaptic vesicles, or microsomes. On immunoblots the mAbs reacted with constitutive brain CV proteins, with cargo molecules, and with a novel CV component that interacts with the actin cytoskeleton. Analysis of radioiodinated brain CVs immunoprecipitated with a tubulin antibody revealed that all brain CVs contained tubulin. The mAb A-7C11 recognized a 40-kilodalton (kDa) polypeptide on the clathrin coat and immunoprecipitated one-quarter of the total brain CVs. The mAb S-11D9 reacted with a 44-kDa antigen and immunoprecipitated 25% of the CVs. This antigen (44 kDa) was present in synaptic vesicles and synaptosomal membrane as well. Moreover, this mAb (S-11D9) reacted with a polypeptide of 56 kDa detected only in synaptosomal membrane. A mAb (C-10B2) that reacted with one of the clathrin light chains (LCb) immunoprecipitated 90% of the brain CVs. One of the mAbs immunoprecipitated a CV subtype that displayed a reversed ratio of the clathrin LCs (LCa greater than LCb). Each of the mAbs yielded different immunofluorescent staining patterns of vesicles in culture cell types that included nerve growth factor-differentiated PC12 cells, neuroblastoma cells, and Madin Darby bovine kidney cells. The data suggest that in brain tissue there is a heterogeneous population of CVs with different polypeptide compositions and subcellular distributions and that each of these subtypes performs a different role in nerve cells.
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Affiliation(s)
- S Puszkin
- Laboratory of Molecular and Cellular Pathology, Mount Sinai School of Medicine, City University of New York, NY 10029
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Kara T, Ishihara H, Aramaki Y, Tsuchiya S. Specific uptake of asialofetuin-labeled liposomes by isolated hepatocytes. Int J Pharm 1988. [DOI: 10.1016/0378-5173(88)90162-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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14
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Spangler RS. Selective insulinization of liver in conscious diabetic dogs. THE AMERICAN JOURNAL OF PHYSIOLOGY 1985; 249:E152-9. [PMID: 3895975 DOI: 10.1152/ajpendo.1985.249.2.e152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Insulin encapsulated in lipid vesicles and targeted to hepatocytes by means of a digalactosyl diglyceride moiety [(designated vesicle encapsulated insulin (VEI)] was administered intravenously to conscious catheterized diabetic dogs to determine the effects of hepatic and extrahepatic glucose utilization. Our results indicate that VEI administered intravenously to diabetic dogs over a dose range of 0.5 to 2.0 mU X kg-1 X min-1 reduces hepatic glucose output or induces hepatic glucose uptake without causing any significant alteration in the rate of extrahepatic glucose utilization. Steady-state comparisons of 1.0 mU X kg-1 X min-1 VEI with intraportal and peripherally administered insulin revealed that VEI and intraportal insulin result in significantly less extrahepatic glucose utilization than does an equivalent dose of peripherally administered insulin (6.36 +/- 1.21 and 5.08 +/- 0.97 vs. 8.82 +/- 1.61 mg X kg-1 X min-1; P less than 0.03). Through the use of VEI, we were able to significantly alter the deposition of intravenously administered glucose from 11% hepatic and 89% extrahepatic noted with peripheral insulin to 35% hepatic and 65% extrahepatic with VEI (P less than 0.03). Thus, by encapsulating insulin into a lipid carrier specifically targeted to the liver, selective hepatic insulinization can be achieved. As a result of this approach, one can alter the distribution of a glucose load to favor hepatic deposition.
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Geuze HJ, Slot JW, Strous GJ, Peppard J, von Figura K, Hasilik A, Schwartz AL. Intracellular receptor sorting during endocytosis: comparative immunoelectron microscopy of multiple receptors in rat liver. Cell 1984; 37:195-204. [PMID: 6327050 DOI: 10.1016/0092-8674(84)90315-5] [Citation(s) in RCA: 306] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Using double-label quantitative immunoelectron microscopy on ultrathin cryosections of rat liver, we have compared the endocytotic pathways of the receptors for asialoglycoprotein (ASGP-R), mannose-6-phosphate ligands (MP-R), and polymeric IgA (IgA-R). All three were found within the Golgi complex, along the entire plasma membrane, in coated pits and vesicles, and within a compartment of uncoupling of receptors and ligand ( CURL ). The receptors occurred randomly at the cell surface, in coated pits and vesicles. Within CURL tubules ASGP-R and MP-R were colocalized , but IgA-R and ASGP-R displayed dramatic microheterogeneity. Thus, in addition to its role in uncoupling and sorting recycling receptor from ligand, CURL serves as a compartment to segregate recycling receptor (e.g. ASGP-R) from receptor involved in transcytosis (e.g. IgA-R).
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16
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Ciechanover A, Schwartz AL, Lodish HF. Sorting and recycling of cell surface receptors and endocytosed ligands: the asialoglycoprotein and transferrin receptors. J Cell Biochem 1983; 23:107-30. [PMID: 6327736 DOI: 10.1002/jcb.240230111] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
With few exceptions, receptor-mediated endocytosis of specific ligands is mediated through clustering of receptor-ligand complexes in coated pits on the cell surface, followed by internalization of the complex into endocytic vesicles. During this process, ligand-receptor dissociation occurs, most probably in a low pH prelysosomal compartment. In most cases the ligand is ultimately directed to the lysosomes, wherein it is degraded, while the receptor recycles to the cell surface. We have studied the kinetics of internalization and recycling of both the asialoglycoprotein receptor and the transferrin receptor in a human hepatoma cell line. By employing both biochemical and morphological/immunocytochemical approaches, we have gained some insight into the complex mechanisms which govern receptor recycling as well as ligand sorting and targeting. We can, in particular, explain why transferrin is exocytosed intact from the cells, while asialoglycoproteins are degraded in lysosomes. We have also localized the intracellular site at which endocytosed receptor and ligand dissociate.
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