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Kinoshita N, Yamamoto TS, Yasue N, Takagi C, Fujimori T, Ueno N. Force-dependent remodeling of cytoplasmic ZO-1 condensates contributes to cell-cell adhesion through enhancing tight junctions. iScience 2022; 25:103846. [PMID: 35198899 PMCID: PMC8850805 DOI: 10.1016/j.isci.2022.103846] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 12/22/2021] [Accepted: 01/25/2022] [Indexed: 12/01/2022] Open
Abstract
The physiological importance of biomolecular condensates is widely recognized, but how it is controlled in time and space during development is largely unknown. Here, we show that a tight junction protein ZO-1 forms cytoplasmic condensates in the trophectoderm (TE) of the mouse embryo before E4.0. These disappear via dissolution, and ZO-1 accumulates at the cell junction as the blastocyst cavity grows and internal pressure on TE cells increases. In contrast, this dissolution was less evident in TE cells attached to the inner cell mass because they receive weaker tensile forces. Furthermore, analyses using MDCK cells demonstrated that the ZO-1 condensates are generated and maintained by liquid-liquid phase separation. Our study also highlights that the dynamics of these condensates depends on the physical environment via an interaction between ZO-1 and F-actin. We propose that the force-dependent regulation of ZO-1 condensation contributes to the establishment of robust cell-cell adhesion during early development. ZO-1 forms cytoplasmic droplets via liquid-liquid phase separation In hatching mouse embryos, ZO-1 droplets dissolve and it localizes to cell junctions In MDCK cells, ZO-1 forms droplets in response to mechanical environments Interaction with F-actin negatively regulates ZO-1 phase separation
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Affiliation(s)
- Noriyuki Kinoshita
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan.,School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Takamasa S Yamamoto
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Naoko Yasue
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Chiyo Takagi
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Toshihiko Fujimori
- Division of Embryology, Department of Developmental Biology, National Institute for Basic Biology, 5-1 Higashiyama Myodaiji, Okazaki, Aichi 444-8787, Japan.,School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Naoto Ueno
- Division of Morphogenesis, Department of Developmental Biology, National Institute for Basic Biology, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan.,School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan.,Unit of Quantitative and Imaging Biology, International Research Collaboration Center, National Institutes of Natural Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
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Mouse and Fly Sperm Motility Changes Differently under Modelling Microgravity. Curr Issues Mol Biol 2021; 43:590-604. [PMID: 34287235 PMCID: PMC8929020 DOI: 10.3390/cimb43020043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 11/26/2022] Open
Abstract
Sperm motility is essential for the natural fertilization process in most animal species. Despite the fact that evolution took place under conditions of constant gravity, the motility of spermatozoa of insects and mammals under microgravity conditions changes in different ways. In this work, an attempt was made to explain this effect. The sperm motility of the fruit fly Drosophila melanogaster and the mouse was evaluated after exposure to a random positioning machine for 6 h. Sodium fluoride was used to inhibit serine/threonine phosphatases, sodium orthovanadate was used to inhibit tyrosine phosphatases, and 6-(dimethylamino)purine was used to inhibit protein kinases. The results obtained indicate that simulated microgravity leads to an increase in the speed of movement of fly spermatozoa by 30% (p < 0.05), and this effect is blocked by sodium fluoride. In contrast, a 29% (p < 0.05) decrease in the speed of movement of mouse spermatozoa under simulated microgravity is prevented by 6-(dimethylamino)purine. Moreover, after 6 h of exposure, the content of tubulin cytoskeleton and actin proteins remains at the control level in the spermatozoa of flies and mice. However, the content of the actin-binding protein alpha-actinin in fly sperm decreases by 29% (p < 0.05), while in mouse sperm, the relative content of alpha-actinin1 increases by 94% (p < 0.05) and alpha-actinin4 by 121% (p < 0.05) relative to the control, as determined by 6 simulated microgravity tests. It can be assumed that the effect of simulated microgravity on the motility of mammalian spermatozoa is mediated through the regulation of phosphorylation and that of insects through the regulation of dephosphorylation of motor proteins; moreover, the development of a response to changes in external mechanical conditions has a different time scale.
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Sun B, Qu R, Fan T, Yang Y, Jiang X, Khan AU, Zhou Z, Zhang J, Wei K, Ouyang J, Dai J. Actin polymerization state regulates osteogenic differentiation in human adipose-derived stem cells. Cell Mol Biol Lett 2021; 26:15. [PMID: 33858321 PMCID: PMC8048231 DOI: 10.1186/s11658-021-00259-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/03/2021] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Actin is an essential cellular protein that assembles into microfilaments and regulates numerous processes such as cell migration, maintenance of cell shape, and material transport. METHODS In this study, we explored the effect of actin polymerization state on the osteogenic differentiation of human adipose-derived stem cells (hASCs). The hASCs were treated for 7 days with different concentrations (0, 1, 5, 10, 20, and 50 nM) of jasplakinolide (JAS), a reagent that directly polymerizes F-actin. The effects of the actin polymerization state on cell proliferation, apoptosis, migration, and the maturity of focal adhesion-related proteins were assessed. In addition, western blotting and alizarin red staining assays were performed to assess osteogenic differentiation. RESULTS Cell proliferation and migration in the JAS (0, 1, 5, 10, and 20 nM) groups were higher than in the control group and the JAS (50 nM) group. The FAK, vinculin, paxillin, and talin protein expression levels were highest in the JAS (20 nM) group, while zyxin expression was highest in the JAS (50 nM) group. Western blotting showed that osteogenic differentiation in the JAS (0, 1, 5, 10, 20, and 50 nM) group was enhanced compared with that in the control group, and was strongest in the JAS (50 nM) group. CONCLUSIONS In summary, our data suggest that the actin polymerization state may promote the osteogenic differentiation of hASCs by regulating the protein expression of focal adhesion-associated proteins in a concentration-dependent manner. Our findings provide valuable information for exploring the mechanism of osteogenic differentiation in hASCs.
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Affiliation(s)
- Bing Sun
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Rongmei Qu
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Tingyu Fan
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Yuchao Yang
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Xin Jiang
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Asmat Ullah Khan
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China
| | - Zhitao Zhou
- Central Laboratory, Southern Medical University, Guangzhou, China
| | - Jingliao Zhang
- Department of Foot and Ankle Surgery, Henan Luoyang Orthopedic Hospital, Zhengzhou, China
| | - Kuanhai Wei
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Guangdong Provincial Key Laboratory of Bone and Cartilage Regeneration Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jun Ouyang
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China.
| | - Jingxing Dai
- Guangdong Provincial Key Laboratory of Medical Biomechanics and Department of Anatomy, School of Basic Medical Science, Southern Medical University, Guangzhou, China.
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Laurini E, Aulic S, Marson D, Fermeglia M, Pricl S. Cationic Dendrimers for siRNA Delivery: An Overview of Methods for In Vitro/In Vivo Characterization. Methods Mol Biol 2021; 2282:209-244. [PMID: 33928579 DOI: 10.1007/978-1-0716-1298-9_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This chapter reviews the different techniques for analyzing the chemical-physical properties, transfection efficiency, cytotoxicity, and stability of covalent cationic dendrimers (CCDs) and self-assembled cationic dendrons (ACDs) for siRNA delivery in the presence and absence of their nucleic cargos. On the basis of the reported examples, a standard essential set of techniques is described for each step of a siRNA/nanovector (NV) complex characterization process: (1) analysis of the basic chemical-physical properties of the NV per se; (2) characterization of the morphology, size, strength, and stability of the siRNA/NV ensemble; (3) characterization and quantification of the cellular uptake and release of the siRNA fragment; (4) in vitro and (5) in vivo experiments for the evaluation of the corresponding gene silencing activity; and (6) assessment of the intrinsic toxicity of the NV and the siRNA/NV complex.
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Affiliation(s)
- Erik Laurini
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), Department of Engineering and Architecture, University of Trieste, Trieste, Italy.
| | - Suzana Aulic
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Domenico Marson
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Maurizio Fermeglia
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Sabrina Pricl
- Molecular Biology and Nanotechnology Laboratory (MolBNL@UniTs), Department of Engineering and Architecture, University of Trieste, Trieste, Italy
- Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
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Bryniarski MA, Yee BM, Chaves LD, Stahura CM, Yacoub R, Morris ME. Megalin-mediated albumin endocytosis in cultured murine mesangial cells. Biochem Biophys Res Commun 2020; 529:740-746. [PMID: 32736701 DOI: 10.1016/j.bbrc.2020.05.166] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 05/22/2020] [Indexed: 12/25/2022]
Abstract
Endocytosis by podocytes is gaining increased attention as a biologic means of removing large proteins such as serum albumin from the glomerular barrier. Some of this function has been attributed to the megalin/cubilin (Lrp2/Cubn) receptor complex and the albumin recycling protein FcRn (Fcgrt). However, whether other glomerular cells possess the potential to perform this same phenomenon or express these proteins remains uncharacterized. Mesangial cells are uniquely positioned in glomeruli and represent a cell type capable of performing several diverse functions. Here, the expression of megalin and FcRn in murine mesangial cells along with the megalin adaptor protein Dab-2 (Dab2) was shown for the first time. Cubilin mRNA expression was detected, but the absence of the cubilin partner amnionless (Amn) suggested that cubilin is minimally functional, if at all, in these cells. Mesangial cell endocytosis of albumin was characterized and shown to involve a receptor-mediated process. Albumin endocytosis was significantly impaired (p < 0.01) under inducible megalin knockdown conditions in stably transduced mesangial cells. The current work provides both the novel identification of megalin and FcRn in mesangial cells and the functional demonstration of megalin-mediated albumin endocytosis.
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Affiliation(s)
- Mark A Bryniarski
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 303 Pharmacy Building, Buffalo, NY, 14214, USA
| | - Benjamin M Yee
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 303 Pharmacy Building, Buffalo, NY, 14214, USA
| | - Lee D Chaves
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 875 Ellicott St, Buffalo, NY, 14214, USA
| | - Corrine M Stahura
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 875 Ellicott St, Buffalo, NY, 14214, USA
| | - Rabi Yacoub
- Department of Internal Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, 875 Ellicott St, Buffalo, NY, 14214, USA
| | - Marilyn E Morris
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, 303 Pharmacy Building, Buffalo, NY, 14214, USA.
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Amit C, Padmanabhan P, Elchuri SV, Narayanan J. Probing the effect of matrix stiffness in endocytic signalling pathway of corneal epithelium. Biochem Biophys Res Commun 2020; 525:280-285. [PMID: 32087964 DOI: 10.1016/j.bbrc.2020.02.067] [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: 01/28/2020] [Accepted: 02/09/2020] [Indexed: 11/30/2022]
Abstract
Matrix stiffness regulates the physiology of the cells and plays an important role in maintaining its homeostasis. It has been reported to regulate cell division, proliferation, migration, extracellular uptake and various other physiological processes. The alteration in matrix stiffness has also been well reported in various disease pathologies. However, in ocular system, Keratoconus (KC) is an ideal model to study the effect of matrix stiffness on endocytosis since the progression of the disease is controlled by increasing the stromal elasticity. Our study using corneal epithelial and retinal pigment epithelial cell lines showed that ocular cells do respond to matrix stiffness by altering their morphology and endocytic uptake of FITC-Dextran 20 kDa. Further, by using KC epithelium as a clinical model, we hypothesize that change in stromal elasticity may also affect the endocytosis of KC epithelium. Our results clearly showed alteration in the expression of actin binding proteins such as Phosphorylated Cofilin, Profilin, Focal adhesion kinase, and Vinculin. Apart from cytoskeletal rearrangement proteins, we also observed endocytic proteins such as Clathrin, Caveolin1 and Rab 11 to be affected by matrix stiffness. Our study thus establishes connecting role between endocytosis and matrix stiffness which could be used to understand the pathophysiology of keratoconus that it is influenced by both mechanical and biochemical factors.
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Affiliation(s)
- Chatterjee Amit
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya Campus, Chennai, Tamil Nadu, India; School of Chemical and Biotechnology, SASTRA Deemed University, Tanjore, Tamil Nadu, India
| | - Prema Padmanabhan
- Department of Cornea, Medical Research Foundation, Sankara Nethralaya Campus, Chennai, Tamil Nadu, India
| | - Sailaja V Elchuri
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya Campus, Chennai, Tamil Nadu, India
| | - Janakiraman Narayanan
- Department of Nanobiotechnology, Vision Research Foundation, Sankara Nethralaya Campus, Chennai, Tamil Nadu, India.
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He L, Sayers EJ, Watson P, Jones AT. Contrasting roles for actin in the cellular uptake of cell penetrating peptide conjugates. Sci Rep 2018; 8:7318. [PMID: 29743505 PMCID: PMC5943252 DOI: 10.1038/s41598-018-25600-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/25/2018] [Indexed: 12/13/2022] Open
Abstract
The increased need for macromolecular therapeutics, such as peptides, proteins and nucleotides, to reach intracellular targets necessitates more effective delivery vectors and a higher level of understanding of their mechanism of action. Cell penetrating peptides (CPPs) can transport a range of macromolecules into cells, either through direct plasma membrane translocation or endocytosis. All known endocytic pathways involve cell-cortex remodelling, a process shown to be regulated by reorganisation of the actin cytoskeleton. Here using flow cytometry, confocal microscopy and a variety of actin inhibitors we identify how actin disorganisation in different cell types differentially influences the cellular entry of three probes: the CPP octaarginine - Alexa488 conjugate (R8-Alexa488), octaarginine conjugated Enhanced Green Fluorescent Protein (EGFP-R8), and the fluid phase probe dextran. Disrupting actin organisation in A431 skin epithelial cells dramatically increases the uptake of EGFP-R8 and dextran, and contrasts strongly to inhibitory effects observed with transferrin and R8 attached to the fluorophore Alexa488. This demonstrates that uptake of the same CPP can occur via different endocytic processes depending on the conjugated fluorescent entity. Overall this study highlights how cargo influences cell uptake of this peptide and that the actin cytoskeleton may act as a gateway or barrier to endocytosis of drug delivery vectors.
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Affiliation(s)
- L He
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, Cardiff, Wales, CF10 3NB, UK
| | - E J Sayers
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, Cardiff, Wales, CF10 3NB, UK
| | - P Watson
- Cardiff School of Biosciences, The Sir Martin Evans Building, Cardiff University, Cardiff, Wales, CF10 3AX, UK.
| | - A T Jones
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, Cardiff, Wales, CF10 3NB, UK.
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Roberts-Dalton HD, Cocks A, Falcon-Perez JM, Sayers EJ, Webber JP, Watson P, Clayton A, Jones AT. Fluorescence labelling of extracellular vesicles using a novel thiol-based strategy for quantitative analysis of cellular delivery and intracellular traffic. NANOSCALE 2017; 9:13693-13706. [PMID: 28880029 DOI: 10.1039/c7nr04128d] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Extracellular vesicles, including exosomes, are naturally derived nanovesicles generated in and released by numerous cell types. As extracellular entities they have the capacity to interact with neighbouring cells and distant tissues and affect physiological processes as well as being implicated in numerous diseases including tumorigenesis and neurodegeneration. They are also under intense investigation as delivery vectors for biotherapeutics. The ways in which EVs interact with recipient cells to influence cell physiology and deliver a macromolecular payload are at the early stages of exploration. A significant challenge within these studies is the ability to label EVs directly or indirectly with fluorescent probes to allow visualization without compromising functionality. Here, we present a thiol-based fluorescence labelling method allowing comprehensive analysis of the cellular uptake of prostate cancer derived EVs in live cells using confocal microscopy. Labelling of the EVs in this way did not influence their size and had no effect on their ability to induce differentiation of lung fibroblasts to myofibroblasts. For endocytosis analyses, depletion of key endocytic proteins and the use of chemical inhibitors (Dynasore, EIPA, Rottlerin and IPA-3) indicated that fluid-phase endocytosis and/or macropinocytosis was involved in EV internalisation. Over a period of six hours EVs were observed to increasingly co-localise with lysosomes, indicating a possible termination point following internalisation. Overall this method provides new opportunities for analysing the cellular dynamics of EVs as biological entities affecting cell and whole body physiology as well as investigating their potential as drug delivery vectors.
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Affiliation(s)
- H D Roberts-Dalton
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, UK.
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Bedi D, Dennis JC, Morrison EE, Braden TD, Judd RL. Regulation of intracellular trafficking and secretion of adiponectin by myosin II. Biochem Biophys Res Commun 2017; 490:202-208. [PMID: 28606474 DOI: 10.1016/j.bbrc.2017.06.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 06/07/2017] [Indexed: 01/08/2023]
Abstract
Adiponectin is a protein secreted by white adipocytes that plays an important role in insulin action, energy homeostasis and the development of atherosclerosis. The intracellular localization and trafficking of GLUT4 and leptin in adipocytes has been well studied, but little is known regarding the intracellular trafficking of adiponectin. Recent studies have demonstrated that constitutive adiponectin secretion is dependent on PIP2 levels and the integrity of cortical F-actin. Non-muscle myosin II is an actin-based motor that is associated with membrane vesicles and participates in vesicular trafficking in mammalian cells. Therefore, we investigated the role of myosin II in the trafficking and secretion of adiponectin in 3T3-L1 adipocytes. Confocal microscopy revealed that myosin IIA and IIB were dispersed throughout the cytoplasm of the adipocyte. Both myosin isoforms were localized in the Golgi/TGN region as evidenced by colocalization with the cis-Golgi marker, p115 and the trans-Golgi marker, γ-adaptin. Inhibition of myosin II activity by blebbistatin or actin depolymerization by latrunculin B dispersed myosin IIA and IIB towards the periphery while significantly inhibiting adiponectin secretion. Therefore, the constitutive trafficking and secretion of adiponectin in 3T3-L1 adipocytes occurs by an actin-dependent mechanism that involves the actin-based motors, myosin IIA and IIB.
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Affiliation(s)
- Deepa Bedi
- Department of Biomedical Sciences, College of Veterinary Medicine, Tuskegee University, Tuskegee, AL, United States.
| | - John C Dennis
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States
| | - Edward E Morrison
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States
| | - Tim D Braden
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States
| | - Robert L Judd
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States
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Gündel D, Allmeroth M, Reime S, Zentel R, Thews O. Endocytotic uptake of HPMA-based polymers by different cancer cells: impact of extracellular acidosis and hypoxia. Int J Nanomedicine 2017; 12:5571-5584. [PMID: 28831253 PMCID: PMC5548275 DOI: 10.2147/ijn.s136952] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Background Polymeric nanoparticles allow to selectively transport chemotherapeutic drugs to the tumor tissue. These nanocarriers have to be taken up into the cells to release the drug. In addition, tumors often show pathological metabolic characteristics (hypoxia and acidosis) which might affect the polymer endocytosis. Materials and methods Six different N-(2-hydroxypropyl)methacrylamide (HPMA)-based polymer structures (homopolymer as well as random and block copolymers with lauryl methacrylate containing hydrophobic side chains) varying in molecular weight and size were analyzed in two different tumor models. The cellular uptake of fluorescence-labeled polymers was measured under hypoxic (pO2 ≈1.5 mmHg) and acidic (pH 6.6) conditions. By using specific inhibitors, different endocytotic routes (macropinocytosis and clathrin-mediated, dynamin-dependent, cholesterol-dependent endocytosis) were analyzed separately. Results The current results revealed that the polymer uptake depends on the molecular structure, molecular weight and tumor line used. In AT1 cells, the uptake of random copolymer was five times stronger than the homopolymer, whereas in Walker-256 cells, the uptake of all polymers was much stronger, but this was independent of the molecular structure and size. Acidosis increased the uptake of random copolymer in AT1 cells but reduced the intracellular accumulation of homopolymer and block copolymer. Hypoxia reduced the uptake of all polymers in Walker-256 cells. Hydrophilic polymers (homopolymer and block copolymer) were taken up by all endocytotic routes studied, whereas the more lipophilic random copolymer seemed to be taken up preferentially by cholesterol- and dynamin-dependent endocytosis. Conclusion The study indicates that numerous parameters of the polymer (structure, size) and of the tumor (perfusion, vascular permeability, pH, pO2) modulate drug delivery, which makes it difficult to select the appropriate polymer for the individual patient.
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Affiliation(s)
- Daniel Gündel
- Institute of Physiology, Martin Luther University Halle-Wittenberg, Halle (Saale)
| | - Mareli Allmeroth
- Institute of Organic Chemistry, Johannes Gutenberg-University, Mainz, Germany
| | - Sarah Reime
- Institute of Physiology, Martin Luther University Halle-Wittenberg, Halle (Saale)
| | - Rudolf Zentel
- Institute of Organic Chemistry, Johannes Gutenberg-University, Mainz, Germany
| | - Oliver Thews
- Institute of Physiology, Martin Luther University Halle-Wittenberg, Halle (Saale)
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Hosseinibarkooie S, Peters M, Torres-Benito L, Rastetter R, Hupperich K, Hoffmann A, Mendoza-Ferreira N, Kaczmarek A, Janzen E, Milbradt J, Lamkemeyer T, Rigo F, Bennett C, Guschlbauer C, Büschges A, Hammerschmidt M, Riessland M, Kye M, Clemen C, Wirth B. The Power of Human Protective Modifiers: PLS3 and CORO1C Unravel Impaired Endocytosis in Spinal Muscular Atrophy and Rescue SMA Phenotype. Am J Hum Genet 2016; 99:647-665. [PMID: 27499521 DOI: 10.1016/j.ajhg.2016.07.014] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 07/14/2016] [Indexed: 12/13/2022] Open
Abstract
Homozygous loss of SMN1 causes spinal muscular atrophy (SMA), the most common and devastating childhood genetic motor-neuron disease. The copy gene SMN2 produces only ∼10% functional SMN protein, insufficient to counteract development of SMA. In contrast, the human genetic modifier plastin 3 (PLS3), an actin-binding and -bundling protein, fully protects against SMA in SMN1-deleted individuals carrying 3-4 SMN2 copies. Here, we demonstrate that the combinatorial effect of suboptimal SMN antisense oligonucleotide treatment and PLS3 overexpression-a situation resembling the human condition in asymptomatic SMN1-deleted individuals-rescues survival (from 14 to >250 days) and motoric abilities in a severe SMA mouse model. Because PLS3 knockout in yeast impairs endocytosis, we hypothesized that disturbed endocytosis might be a key cellular mechanism underlying impaired neurotransmission and neuromuscular junction maintenance in SMA. Indeed, SMN deficit dramatically reduced endocytosis, which was restored to normal levels by PLS3 overexpression. Upon low-frequency electro-stimulation, endocytotic FM1-43 (SynaptoGreen) uptake in the presynaptic terminal of neuromuscular junctions was restored to control levels in SMA-PLS3 mice. Moreover, proteomics and biochemical analysis revealed CORO1C, another F-actin binding protein, whose direct binding to PLS3 is dependent on calcium. Similar to PLS3 overexpression, CORO1C overexpression restored fluid-phase endocytosis in SMN-knockdown cells by elevating F-actin amounts and rescued the axonal truncation and branching phenotype in Smn-depleted zebrafish. Our findings emphasize the power of genetic modifiers to unravel the cellular pathomechanisms underlying SMA and the power of combinatorial therapy based on splice correction of SMN2 and endocytosis improvement to efficiently treat SMA.
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Briceño MP, Nascimento LAC, Nogueira NP, Barenco PVC, Ferro EAV, Rezende-Oliveira K, Goulart LR, Alves PT, Barbosa BDF, Lima WR, Silva NM. Toxoplasma gondii Infection Promotes Epithelial Barrier Dysfunction of Caco-2 Cells. J Histochem Cytochem 2016; 64:459-69. [PMID: 27370796 DOI: 10.1369/0022155416656349] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022] Open
Abstract
After oral infection, Toxoplasma gondii invades intestinal cells, induces breakdown of intestinal physiology and barrier functions, and causes intestinal pathology in some animal species. Although parasites' invasion into host cells is a known phenomenon, the effects of T. gondii infection in the intestinal barrier are still not well established. To evaluate morphological and physiological modifications on the colorectal adenocarcinoma-derived Caco-2 cell line during T. gondii infection, microvilli, tight junction integrity, and transepithelial electrical resistance (TEER) were investigated under infection. It was observed that the dextran uptake (endocytosis) and distribution were smaller in infected than in noninfected Caco-2 cells. The infection leads to the partial loss of microvilli at the cell surface. Claudin-1, zonula occludens-1 (ZO-1), and occludin expressions were colocalized by immunofluorescence and presented discontinuous net patterns in infected cells. Immunoblotting analysis at 24 hr postinfection revealed decreasing expression of occludin and ZO-1 proteins, whereas claudin-1 presented similar expression level compared with noninfected cells. T. gondii decreased TEER in Caco-2 cells 24 hr after infection. Our results suggest that T. gondii infection may lead to the loss of integrity of intestinal mucosa, resulting in impaired barrier function.
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Affiliation(s)
- Marisol Pallete Briceño
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| | | | - Nathalia Pires Nogueira
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
| | | | - Eloisa Amália Vieira Ferro
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
| | - Karine Rezende-Oliveira
- Laboratory of Biomedical Sciences, Federal University of Uberlândia, Ituiutaba, Minas Gerais, Brazil (KR-O)
| | - Luiz Ricardo Goulart
- Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
| | - Patrícia Terra Alves
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Laboratory of Nanobiotechnology, Institute of Genetics and Biochemistry, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (LRG, PTA)
| | - Bellisa de Freitas Barbosa
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, Minas Gerais, Brazil (BFB, EAVF)
| | - Wânia Rezende Lima
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS),Institute of Exact and Natural Sciences, Federal University of Mato Grosso, Rondonópolis, Mato Grosso, Brazil (WRL)
| | - Neide Maria Silva
- Laboratory of Immunopathology, Institute of Biomedical Sciences (MPB, LACN, NPN, PVCB, WRL, NMS)
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Actin-Dynamics in Plant Cells: The Function of Actin-Perturbing Substances: Jasplakinolide, Chondramides, Phalloidin, Cytochalasins, and Latrunculins. Methods Mol Biol 2016; 1365:243-61. [PMID: 26498789 DOI: 10.1007/978-1-4939-3124-8_13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This chapter gives an overview of the most common F-actin-perturbing substances that are used to study actin dynamics in living plant cells in studies on morphogenesis, motility, organelle movement, or when apoptosis has to be induced. These substances can be divided into two major subclasses: F-actin-stabilizing and -polymerizing substances like jasplakinolide and chondramides and F-actin-severing compounds like chytochalasins and latrunculins. Jasplakinolide was originally isolated form a marine sponge, and can now be synthesized and has become commercially available, which is responsible for its wide distribution as membrane-permeable F-actin-stabilizing and -polymerizing agent, which may even have anticancer activities. Cytochalasins, derived from fungi, show an F-actin-severing function and many derivatives are commercially available (A, B, C, D, E, H, J), also making it a widely used compound for F-actin disruption. The same can be stated for latrunculins (A, B), derived from red sea sponges; however the mode of action is different by binding to G-actin and inhibiting incorporation into the filament. In the case of swinholide a stable complex with actin dimers is formed resulting also in severing of F-actin. For influencing F-actin dynamics in plant cells only membrane permeable drugs are useful in a broad range. We however introduce also the phallotoxins and synthetic derivatives, as they are widely used to visualize F-actin in fixed cells. A particular uptake mechanism has been shown for hepatocytes, but has also been described in siphonal giant algae. In the present chapter the focus is set on F-actin dynamics in plant cells where alterations in cytoplasmic streaming can be particularly well studied; however methods by fluorescence applications including phalloidin and antibody staining as well as immunofluorescence-localization of the inhibitor drugs are given.
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Lee SJ, Seo BR, Koh JY. Metallothionein-3 modulates the amyloid β endocytosis of astrocytes through its effects on actin polymerization. Mol Brain 2015; 8:84. [PMID: 26637294 PMCID: PMC4670512 DOI: 10.1186/s13041-015-0173-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 11/30/2015] [Indexed: 12/30/2022] Open
Abstract
Background Astrocytes may play important roles in the pathogenesis of Alzheimer’s disease (AD) by clearing extracellular amyloid beta (Aβ) through endocytosis and degradation. We recently showed that metallothionein 3 (Mt3), a zinc-binding metallothionein that is enriched in the central nervous system, contributes to actin polymerization in astrocytes. Because actin is likely involved in the endocytosis of Aβ, we investigated the possible role of Mt3 in Aβ endocytosis by cortical astrocytes in this study. Results To assess the route of Aβ uptake, we exposed cultured astrocytes to fluorescently labeled Aβ1–40 or Aβ1–42 together with chloropromazine (CP) or methyl-beta-cyclodextrin (MβCD), inhibitors of clathrin- and caveolin-dependent endocytosis, respectively. CP treatment almost completely blocked Aβ1–40 and Aβ1–42 endocytosis, whereas exposure to MβCD had no significant effect. Actin disruption with cytochalasin D (CytD) or latrunculin B also completely blocked Aβ1–40 and Aβ1–42 endocytosis. Because the absence of Mt3 also results in actin disruption, we examined Aβ1–40 and Aβ1–42 uptake and expression in Mt3−/− astrocytes. Compared with wild-type (WT) cells, Mt3−/− cells exhibited markedly reduced Aβ1–40 and Aβ1–42 endocytosis and expression of Aβ1-42 monomers and oligomers. A similar reduction was observed in CytD-treated WT cells. Finally, actin disruption and Mt3 knockout each increased the overall levels of clathrin and the associated protein phosphatidylinositol-binding clathrin assembly protein (PICALM) in astrocytes. Conclusions Our results suggest that the absence of Mt3 reduces Aβ uptake in astrocytes through an abnormality in actin polymerization. In light of evidence that Mt3 is downregulated in AD, our findings indicate that this mechanism may contribute to the extracellular accumulation of Aβ in this disease.
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Affiliation(s)
- Sook-Jeong Lee
- Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea. .,Present address: Department of New Drug Discovery and Development, Chungnam National University, 99 Daehak-ro, Yuseong, Daejeon, 34134, South Korea.
| | - Bo-Ra Seo
- Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea.
| | - Jae-Young Koh
- Neural Injury Research Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, South Korea. .,Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-Gil, Songpa-Gu, Seoul, 05505, South Korea.
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Seebacher NA, Lane DJR, Jansson PJ, Richardson DR. Glucose Modulation Induces Lysosome Formation and Increases Lysosomotropic Drug Sequestration via the P-Glycoprotein Drug Transporter. J Biol Chem 2015; 291:3796-820. [PMID: 26601947 DOI: 10.1074/jbc.m115.682450] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Indexed: 11/06/2022] Open
Abstract
Pgp is functional on the plasma membrane and lysosomal membrane. Lysosomal-Pgp can pump substrates into the organelle, thereby trapping certain chemotherapeutics (e.g. doxorubicin; DOX). This mechanism serves as a "safe house" to protect cells against cytotoxic drugs. Interestingly, in contrast to DOX, lysosomal sequestration of the novel anti-tumor agent and P-glycoprotein (Pgp) substrate, di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT), induces lysosomal membrane permeabilization. This mechanism of lysosomal-Pgp utilization enhances cytotoxicity to multidrug-resistant cells. Consequently, Dp44mT has greater anti-tumor activity in drug-resistant relative to non-Pgp-expressing tumors. Interestingly, stressors in the tumor microenvironment trigger endocytosis for cell signaling to assist cell survival. Hence, this investigation examined how glucose variation-induced stress regulated early endosome and lysosome formation via endocytosis of the plasma membrane. Furthermore, the impact of glucose variation-induced stress on resistance to DOX was compared with Dp44mT and its structurally related analogue, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC). These studies showed that glucose variation-induced stress-stimulated formation of early endosomes and lysosomes. In fact, through the process of fluid-phase endocytosis, Pgp was redistributed from the plasma membrane to the lysosomal membrane via early endosome formation. This lysosomal-Pgp actively transported the Pgp substrate, DOX, into the lysosome where it became trapped as a result of protonation at pH 5. Due to increased lysosomal DOX trapping, Pgp-expressing cells became more resistant to DOX. In contrast, cytotoxicity of Dp44mT and DpC was potentiated due to more lysosomes containing functional Pgp under glucose-induced stress. These thiosemicarbazones increased lysosomal membrane permeabilization and cell death. This mechanism has critical implications for drug-targeting in multidrug-resistant tumors where a stressful micro-environment exists.
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Affiliation(s)
- Nicole A Seebacher
- From the Molecular Pharmacology and Pathology Program, Department of Pathology, Blackburn Building (D06), University of Sydney, New South Wales, Australia 2006
| | - Darius J R Lane
- From the Molecular Pharmacology and Pathology Program, Department of Pathology, Blackburn Building (D06), University of Sydney, New South Wales, Australia 2006
| | - Patric J Jansson
- From the Molecular Pharmacology and Pathology Program, Department of Pathology, Blackburn Building (D06), University of Sydney, New South Wales, Australia 2006
| | - Des R Richardson
- From the Molecular Pharmacology and Pathology Program, Department of Pathology, Blackburn Building (D06), University of Sydney, New South Wales, Australia 2006
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Ashjaei K, Palmberger D, Bublin M, Bajna E, Breiteneder H, Grabherr R, Ellinger I, Hoffmann-Sommergruber K. Atopic donor status does not influence the uptake of the major grass pollen allergen, Phl p 5, by dendritic cells. J Immunol Methods 2015; 424:120-30. [PMID: 26055335 PMCID: PMC4739503 DOI: 10.1016/j.jim.2015.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 02/02/2023]
Abstract
Dendritic cells (DCs) are sentinels of the immune system for antigen recognition and uptake, as well as presentation to naïve T cells for stimulation or priming. Internalization and endocytic degradation of allergens by DCs are important steps required for T cell priming. In the current study we investigated binding and internalization of purified recombinant non-glycosylated grass pollen allergen, Phl p 5, and natural non-specific lipid transfer protein from sunflower, SF-nsLTP to human monocyte derived dendritic cells (MoDCs). Colocalization of Phl p 5 with low affinity (CD23) or high affinity receptor (FcεRI) was investigated by immunofluorescence staining. Likewise, localization of the allergens in early (EE) and late endosomes (LE) was detected by co-staining for early endosome antigen (EEA1) and lysosomal-associated membrane protein 1 (LAMP1). In our experimental setting we could demonstrate that Phl p 5 as well as SF-nsLTP bound to MoDCs from both, grass pollen allergic and non-allergic individuals. Competitive allergen uptake experiments demonstrated non-preferential and simultaneous uptake of Phl p 5 and SF-nsLTP by MoDCs. No overlap of signals from Phl p 5 and CD23 or FcεRI was detectable, excluding IgE-mediated uptake for this allergen. Both allergens, Phl p 5 and SF-nsLTP, were localized in early and late endosomes. The present study applied a set of methods to assess the allergen uptake by MoDCs in an in vitro model. No qualitative and quantitative differences in the allergen uptake of both, Phl p 5 and SF-nsLTP were detected in single and competitive assays.
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Affiliation(s)
- Kazem Ashjaei
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
| | - Dieter Palmberger
- Vienna Institute of Biotechnology - VIBT, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Merima Bublin
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
| | - Erika Bajna
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
| | - Heimo Breiteneder
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
| | - Reingard Grabherr
- Vienna Institute of Biotechnology - VIBT, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Isabella Ellinger
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.
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Soleimanpour SA, Gupta A, Bakay M, Ferrari AM, Groff DN, Fadista J, Spruce LA, Kushner JA, Groop L, Seeholzer SH, Kaufman BA, Hakonarson H, Stoffers DA. The diabetes susceptibility gene Clec16a regulates mitophagy. Cell 2014; 157:1577-90. [PMID: 24949970 DOI: 10.1016/j.cell.2014.05.016] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 02/24/2014] [Accepted: 05/09/2014] [Indexed: 12/22/2022]
Abstract
Clec16a has been identified as a disease susceptibility gene for type 1 diabetes, multiple sclerosis, and adrenal dysfunction, but its function is unknown. Here we report that Clec16a is a membrane-associated endosomal protein that interacts with E3 ubiquitin ligase Nrdp1. Loss of Clec16a leads to an increase in the Nrdp1 target Parkin, a master regulator of mitophagy. Islets from mice with pancreas-specific deletion of Clec16a have abnormal mitochondria with reduced oxygen consumption and ATP concentration, both of which are required for normal β cell function. Indeed, pancreatic Clec16a is required for normal glucose-stimulated insulin release. Moreover, patients harboring a diabetogenic SNP in the Clec16a gene have reduced islet Clec16a expression and reduced insulin secretion. Thus, Clec16a controls β cell function and prevents diabetes by controlling mitophagy. This pathway could be targeted for prevention and control of diabetes and may extend to the pathogenesis of other Clec16a- and Parkin-associated diseases.
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Affiliation(s)
- Scott A Soleimanpour
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine and the Institute for Diabetes, Obesity and Metabolism of the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Division of Metabolism, Endocrinology & Diabetes and Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Aditi Gupta
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine and the Institute for Diabetes, Obesity and Metabolism of the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Marina Bakay
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alana M Ferrari
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine and the Institute for Diabetes, Obesity and Metabolism of the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - David N Groff
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine and the Institute for Diabetes, Obesity and Metabolism of the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - João Fadista
- Lund University Diabetes Center, Department of Clinical Sciences, Diabetes & Endocrinology, Skåne University Hospital, Lund University, SE-205 02 Malmö, Sweden
| | - Lynn A Spruce
- Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Jake A Kushner
- McNair Medical Institute, Pediatric Diabetes and Endocrinology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Leif Groop
- Lund University Diabetes Center, Department of Clinical Sciences, Diabetes & Endocrinology, Skåne University Hospital, Lund University, SE-205 02 Malmö, Sweden
| | - Steven H Seeholzer
- Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Brett A Kaufman
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Doris A Stoffers
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine and the Institute for Diabetes, Obesity and Metabolism of the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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Ghosh S, Ucer KB, D'Agostino R, Grant K, Sirintrapun J, Thomas MJ, Hantgan R, Bharadwaj M, Gmeiner WH. Non-covalent assembly of meso-tetra-4-pyridyl porphine with single-stranded DNA to form nano-sized complexes with hydrophobicity-dependent DNA release and anti-tumor activity. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2014; 10:451-61. [PMID: 23988714 PMCID: PMC3946208 DOI: 10.1016/j.nano.2013.07.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 07/22/2013] [Indexed: 11/30/2022]
Abstract
DNA and porphyrin based therapeutics are important for anti-cancer treatment. The present studies demonstrate single-stranded DNA (ssDNA) assembles with meso-tetra-4-pyridyl porphine (MTP) forming porphyrin:DNA nano-complexes (PDN) that are stable in aqueous solution under physiologically relevant conditions and undergo dissociation with DNA release in hydrophobic environments, including cell membranes. PDN formation is DNA-dependent with the ratio of porphyrin:DNA being approximately two DNA nucleobases per porphyrin. PDN produce reactive oxygen species (ROS) in a light-dependent manner under conditions that favor nano-complex dissociation in the presence of hydrophobic solvents. PDN induce light-dependent cytotoxicity in vitro and anti-tumor activity towards bladder cancer xenografts in vivo. Light-dependent, PDN-mediated cell death results from ROS-mediated localized membrane damage due to lipid peroxidation with mass spectrometry indicating the generation of the lipid peroxidation products 9- and 13-hydroxy octadecanoic acid. Our results demonstrate that PDN have properties useful for therapeutic applications, including cancer treatment. FROM THE CLINICAL EDITOR In this study, porphyrin-DNA nanocomplexes were investigated as anti-cancer therapeutics inducing ROS production in a light-dependent manner. Efficacy is demonstrated in vitro as well as a in a bladder cancer xenograft model.
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Affiliation(s)
- Supratim Ghosh
- Program in Molecular Genetics, Wake Forest School of Medicine, Winston-Salem, NC, USA; Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Kamil B Ucer
- Department of Physics, Wake Forest University, Winston-Salem, NC, USA
| | - Ralph D'Agostino
- Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Ken Grant
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Joseph Sirintrapun
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Michael J Thomas
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Roy Hantgan
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Manish Bharadwaj
- Department of Genrontology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - William H Gmeiner
- Program in Molecular Genetics, Wake Forest School of Medicine, Winston-Salem, NC, USA; Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC, USA; Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC, USA.
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Cholesterol-mediated membrane surface area dynamics in neuroendocrine cells. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1228-38. [PMID: 24046863 DOI: 10.1016/j.bbalip.2013.04.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
How cholesterol, a key membrane constituent, affects membrane surface area dynamics in secretory cells is unclear. Using methyl-beta-cyclodextrin (MbetaCD) to deplete cholesterol, we imaged melanotrophs from male Wistar rats in real-time and monitored membrane capacitance (C(m)), fluctuations of which reflect exocytosis and endocytosis. Treatment with MbetaCD reduced cellular cholesterol and caused a dose-dependent attenuation of the Ca(2+)-evoked increase in C(m) (IC50 = 5.3 mM) vs. untreated cells. Cytosol dialysis of MbetaCD enhanced the attenuation of C(m) increase (IC50 = 3.3 mM), suggesting cholesterol depletion at intracellular membrane sites was involved in attenuating exocytosis. Acute extracellular application of MbetaCD resulted in an immediate C(m) decline, which correlated well with the cellular surface area decrease, indicating the involvement of cholesterol in the regulation of membrane surface area dynamics. This decline in C(m) was three-fold slower than MbetaCD-mediated fluorescent cholesterol decay, implying that exocytosis is the likely physiological means for plasma membrane cholesterol replenishment. MbetaCD had no effect on the specific C(m) and the blockade of endocytosis by Dyngo 4a, confirmed by inhibition of dextran uptake, also had no effect on the time-course of MbetaCD-induced C(m) decline. Thus acute exposure to MbetaCD evokes a C(m) decline linked to the removal of membrane cholesterol, which cannot be compensated for by exocytosis. We propose that the primary contribution of cholesterol to surface area dynamics is via its role in regulated exocytosis.
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20
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Shi B, Abrams M. Technologies for investigating the physiological barriers to efficient lipid nanoparticle-siRNA delivery. J Histochem Cytochem 2013; 61:407-20. [PMID: 23504369 PMCID: PMC3715328 DOI: 10.1369/0022155413484152] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/20/2013] [Indexed: 11/22/2022] Open
Abstract
Small interfering RNA (siRNA) therapeutics have advanced from bench to clinical trials in recent years, along with new tools developed to enable detection of siRNA delivered at the organ, cell, and subcellular levels. Preclinical models of siRNA delivery have benefitted from methodologies such as stem-loop quantitative polymerase chain reaction, histological in situ immunofluorescent staining, endosomal escape assay, and RNA-induced silencing complex loading assay. These technologies have accelerated the detection and optimization of siRNA platforms to overcome the challenges associated with delivering therapeutic oligonucleotides to the cytosol of specific target cells. This review focuses on the methodologies and their application in the biodistribution of siRNA delivered by lipid nanoparticles.
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Affiliation(s)
- Bin Shi
- Department of RNA Therapeutics, Merck Research Laboratories, Merck & Co., Inc., West Point, Pennsylvania, USA.
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Okada I, Fujiki S, Iwase S, Abe H. Stabilization of actin filaments prevents germinal vesicle breakdown and affects microtubule organization in Xenopus oocytes. Cytoskeleton (Hoboken) 2012; 69:312-23. [PMID: 22422719 DOI: 10.1002/cm.21028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 02/03/2012] [Accepted: 03/08/2012] [Indexed: 02/04/2023]
Abstract
In Xenopus oocytes, extremely giant nuclei, termed germinal vesicles, contain a large amount of actin filaments most likely for mechanical integrity. Here, we show that microinjection of phalloidin, an F-actin-stabilizing drug, prevents the germinal vesicle breakdown (GVBD) in oocytes treated with progesterone. These nuclei remained for more 12 h after control oocytes underwent GVBD. Immunostaining showed significant elevation of actin in the remaining nuclei and many actin filament bundles in the cytoplasm. Furthermore, microtubules formed unusual structures in both nuclei and cytoplasm of phalloidin-injected oocytes stimulated by progesterone. Cytoplasmic microtubule arrays and intranuclear microtubules initially formed in phalloidin-injected oocytes as control oocytes exhibited white maturation spots; these structures gradually disappeared and finally converged upon intranuclear short bundles when control oocytes completed maturation. In contrast, treatment of oocytes with jasplakinolide, a cell membrane-permeable actin filament-stabilizing drug, did not affect GVBD. This drug preferentially induced accumulation of actin filaments at the cortex without any increase in cytoplasmic actin staining. Based on these results, intranuclear and cytoplasmic actin filament dynamics appear to be required for the completion of GVBD and critically involved in the regulation of microtubule assembly during oocyte maturation in Xenopus laevis.
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Affiliation(s)
- Iyo Okada
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan
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Yumoto R, Suzuka S, Oda K, Nagai J, Takano M. Endocytic uptake of FITC-albumin by human alveolar epithelial cell line A549. Drug Metab Pharmacokinet 2012; 27:336-43. [PMID: 22214936 DOI: 10.2133/dmpk.dmpk-11-rg-127] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The uptake mechanism of FITC-labeled albumin (FITC-albumin) was examined in human alveolar epithelial cell line A549. FITC-albumin uptake by A549 cells was time- and temperature-dependent, and was markedly suppressed at 4°C compared with that at 37°C. The uptake was saturable, and was mediated by a high-affinity, low-capacity system and by a low-affinity, high-capacity system. In the following experiments, we focused on the low-affinity system. FITC-albumin uptake was markedly inhibited by metabolic inhibitors and by a vacuolar H⁺-ATPase, bafilomycin A₁. The uptake was inhibited by clathrin-mediated endocytosis inhibitors (phenylarsine oxide and chlorpromazine). Potassium depletion and hypertonicity that inhibit clathrin-mediated endocytosis also decreased FITC-albumin uptake. On the other hand, caveolae-mediated endocytosis inhibitors (indomethacin and nystatin) did not affect FITC-albumin uptake. In addition, FITC-albumin uptake was inhibited by macropinocytosis inhibitors such as 5-(N-ethyl-N-isopropyl) amiloride. These results suggest that the low-affinity system of FITC-albumin uptake is mediated by endocytosis in A549 cells, predominantly via a clathrin-mediated pathway. Macropinocytosis, but not caveolae-mediated endocytosis, may also be involved. Considering our previous findings, albumin may be transported by a similar mechanism and/or pathway in rat and human alveolar epithelial cells.
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Affiliation(s)
- Ryoko Yumoto
- Department of Pharmaceutics and Therapeutics, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
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Sobo K, Stuart AD, Rubbia-Brandt L, Brown TDK, McKee TA. Echovirus 11 infection induces dramatic changes in the actin cytoskeleton of polarized Caco-2 cells. J Gen Virol 2011; 93:475-487. [PMID: 22090210 DOI: 10.1099/vir.0.037697-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Binding of echovirus 11 strain 207 (EV11-207) to Caco-2 monolayers results in rapid transfer of the virus to tight junctions prior to uptake. Using a confocal microscopy based-method, this study quantified the spatiotemporal distribution of actin during the time course of infection by EV11-207 in Caco-2 polarized cells. It was found that binding of EV11-207 to the apical surface resulted in rapid rearrangement of the actin cytoskeleton, concomitant with transport of the virus particles to tight junctions. By interfering with the actin network dynamics, the virus remained trapped at the cell surface, leading to abortion of infection. In addition, it was observed that at 4 h post-infection, concomitant with the detection of virus replication, actin filament was depolymerized and degraded. Finally, it was shown that the mechanisms leading to loss of actin were independent of viral genome synthesis, indicating a potential role for the viral protein synthesis seen in late infection. These data confirmed a previous study on the requirement for an intact actin cytoskeleton for EV11-207 to infect cells and reinforce the notion of actin cytoskeleton subversion by picornaviruses during infection in polarized epithelial cells.
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Affiliation(s)
- Komla Sobo
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK.,Cell Biology Unit, MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.,Department of Clinical Pathology, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
| | - Amanda D Stuart
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Laura Rubbia-Brandt
- Department of Clinical Pathology, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
| | - T David K Brown
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Thomas A McKee
- Department of Clinical Pathology, University of Geneva, 1 Rue Michel Servet, 1211 Geneva 4, Switzerland
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Agrin triggers the clustering of raft-associated acetylcholine receptors through actin cytoskeleton reorganization. Biol Cell 2011; 103:287-301. [PMID: 21524273 DOI: 10.1042/bc20110018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND INFORMATION Cholesterol/sphingolipid-rich membrane microdomains or membrane rafts have been implicated in various aspects of receptor function such as activation, trafficking and synapse localization. More specifically in muscle, membrane rafts are involved in AChR (acetylcholine receptor) clustering triggered by the neural factor agrin, a mechanism considered integral to NMJ (neuromuscular junction) formation. In addition, actin polymerization is required for the formation and stabilization of AChR clusters in muscle fibres. Since membrane rafts are platforms sustaining actin nucleation, we hypothesize that these microdomains provide the suitable microenvironment favouring agrin/MuSK (muscle-specific kinase) signalling, eliciting in turn actin cytoskeleton reorganization and AChR clustering. However, the identity of the signalling pathways operating through these microdomains still remains unclear. RESULTS In this work, we attempted to identify the interactions between membrane raft components and cortical skeleton that regulate, upon signalling by agrin, the assembly and stabilization of synaptic proteins of the postsynaptic membrane domain at the NMJ. We provide evidence that in C2C12 myotubes, agrin triggers the association of a subset of membrane rafts enriched in AChR, the -MuSK and Cdc42 (cell division cycle 42) to the actin cytoskeleton. Disruption of the liquid-ordered phase by methyl-β-cyclodextrin abolished this association. We further show that actin and the actin-nucleation factors, N-WASP (neuronal Wiscott-Aldrich syndrome protein) and Arp2/3 (actin-related protein 2/3) are transiently associated with rafts on agrin engagement. Consistent with these observations, pharmacological inhibition of N-WASP activity perturbed agrin-elicited AChR clustering. Finally, immunoelectron microscopic analyses of myotube membrane uncovered that AChRs were constitutively associated with raft nanodomains at steady state that progressively coalesced on agrin activation. These rearrangements of membrane domains correlated with the reorganization of cortical actin cytoskeleton through concomitant and transient recruitment of the Arp2/3 complex to AChR-enriched rafts. CONCLUSIONS The present observations support the notion that membrane rafts are involved in AChR clustering by promoting local actin cytoskeleton reorganization through the recruitment of effectors of the agrin/MuSK signalling cascade. These mechanisms are believed to play an important role in vivo in the formation of the NMJ.
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25
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Kohl T, Lörinczi E, Pardo LA, Stühmer W. Rapid internalization of the oncogenic K+ channel K(V)10.1. PLoS One 2011; 6:e26329. [PMID: 22022602 PMCID: PMC3192180 DOI: 10.1371/journal.pone.0026329] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/24/2011] [Indexed: 11/18/2022] Open
Abstract
K(V)10.1 is a mammalian brain voltage-gated potassium channel whose ectopic expression outside of the brain has been proven relevant for tumor biology. Promotion of cancer cell proliferation by K(V)10.1 depends largely on ion flow, but some oncogenic properties remain in the absence of ion permeation. Additionally, K(V)10.1 surface populations are small compared to large intracellular pools. Control of protein turnover within cells is key to both cellular plasticity and homeostasis, and therefore we set out to analyze how endocytic trafficking participates in controlling K(V)10.1 intracellular distribution and life cycle. To follow plasma membrane K(V)10.1 selectively, we generated a modified channel of displaying an extracellular affinity tag for surface labeling by α-bungarotoxin. This modification only minimally affected K(V)10.1 electrophysiological properties. Using a combination of microscopy and biochemistry techniques, we show that K(V)10.1 is constitutively internalized involving at least two distinct pathways of endocytosis and mainly sorted to lysosomes. This occurs at a relatively fast rate. Simultaneously, recycling seems to contribute to maintain basal K(V)10.1 surface levels. Brief K(V)10.1 surface half-life and rapid lysosomal targeting is a relevant factor to be taken into account for potential drug delivery and targeting strategies directed against K(V)10.1 on tumor cells.
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Affiliation(s)
- Tobias Kohl
- Max-Planck-Institute of Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
| | - Eva Lörinczi
- Max-Planck-Institute of Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
| | - Luis A. Pardo
- Max-Planck-Institute of Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
| | - Walter Stühmer
- Max-Planck-Institute of Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany
- DFG Research Center for Molecular Physiology of the Brain (CMPB), Göttingen, Germany
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26
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Contreras J, Elnagar AYO, Hamm-Alvarez SF, Camarero JA. Cellular uptake of cyclotide MCoTI-I follows multiple endocytic pathways. J Control Release 2011; 155:134-43. [PMID: 21906641 DOI: 10.1016/j.jconrel.2011.08.030] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 08/07/2011] [Accepted: 08/23/2011] [Indexed: 12/23/2022]
Abstract
Cyclotides are plant-derived proteins that naturally exhibit various biological activities and whose unique cyclic structure makes them remarkably stable and resistant to denaturation or degradation. These attributes, among others, make them ideally suited for use as drug development tools. This study investigated the cellular uptake of cyclotide, MCoTI-I in live HeLa cells. Using real time confocal fluorescence microscopy imaging, we show that MCoTI-I is readily internalized in live HeLa cells and that its endocytosis is temperature-dependent. Endocytosis of MCoTI-I in HeLa cells is achieved primarily through fluid-phase endocytosis, as evidenced by its significant colocalization with 10K-dextran, but also through other pathways as well, as evidenced by its colocalization with markers for cholesterol-dependent and clathrin-mediated endocytosis, cholera toxin B and EGF respectively. Uptake does not appear to occur only via macropinocytosis as inhibition of this pathway by Latrunculin B-induced disassembly of actin filaments did not affect MCoTI-I uptake and treatment with EIPA which also seemed to inhibit other pathways collectively inhibited approximately 80% of cellular uptake. As well, a significant amount of MCoTI-I accumulates in late endosomal and lysosomal compartments and MCoTI-I-containing vesicles continue to exhibit directed movements. These findings demonstrate internalization of MCoTI-I through multiple endocytic pathways that are dominant in the cell type investigated, suggesting that this cyclotide has ready access to general endosomal/lysosomal pathways but could readily be re-targeted to specific receptors through addition of targeting ligands.
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Affiliation(s)
- Janette Contreras
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA
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27
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Georgieva JV, Kalicharan D, Couraud PO, Romero IA, Weksler B, Hoekstra D, Zuhorn IS. Surface characteristics of nanoparticles determine their intracellular fate in and processing by human blood-brain barrier endothelial cells in vitro. Mol Ther 2010; 19:318-25. [PMID: 21045812 DOI: 10.1038/mt.2010.236] [Citation(s) in RCA: 141] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
A polarized layer of endothelial cells that comprises the blood-brain barrier (BBB) precludes access of systemically administered medicines to brain tissue. Consequently, there is a need for drug delivery vehicles that mediate transendothelial transport of such medicines. Endothelial cells use a variety of endocytotic pathways for the internalization of exogenous materials, including clathrin-mediated endocytosis, caveolar endocytosis, and macropinocytosis. The different modes of endocytosis result in the delivery of endocytosed material to distinctive intracellular compartments and therewith correlated differential processing. To obtain insight into the properties of drug delivery vehicles that direct their intracellular processing in brain endothelial cells, we investigated the intracellular processing of fixed-size nanoparticles in an in vitro BBB model as a function of distinct nanoparticle surface modifications. Caveolar endocytosis, adsorptive-mediated endocytosis, and receptor-mediated endocytosis were promoted by the use of uncoated 500-nm particles, attachment of the cationic polymer polyethyleneimine (PEI), and attachment of prion proteins, respectively. We demonstrate that surface modifications of nanoparticles, including charge and protein ligands, affect their mode of internalization by brain endothelial cells and thereby their subcellular fate and transcytotic potential.
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Affiliation(s)
- Julia V Georgieva
- Department of Cell Biology, University of Groningen, Groningen, The Netherlands
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28
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Holzinger A. Jasplakinolide: an actin-specific reagent that promotes actin polymerization. Methods Mol Biol 2010; 586:71-87. [PMID: 19768425 DOI: 10.1007/978-1-60761-376-3_4] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Jasplakinolide, a cyclo-depsipeptide is a commonly used actin filament polymerizing and stabilizing drug. The substance has originally been isolated from a marine sponge, and can now be synthesized and has become commercially available. This, together with the benefit that jasplakinolide is membrane permeable has made it a commonly used tool in cell biology, when actin filament stabilization or polymerization has to be achieved. This may either be the case in studies on morphogenesis, motility, organelle movement, or when apoptosis has to be induced. Its use as a potent anticancer drug is discussed. The direct action on actin filaments may have further consequences in golgi body and membrane raft protein organization. In this chapter, the visualization of jasplaklinolide effects by different fluorescent and transmission electron microscopic methods is described. As competitive binding capacities of jasplakinolide and phalloidin make the detection of actin filaments by fluorescently labeled phalloidin problematic, alternatives are given here.
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Affiliation(s)
- Andreas Holzinger
- Institute of Botany, Department of Physiology and Cell Physiology, University of Innsbruck, Innsbruck, Austria
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29
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Kidd M, Hauso Ø, Drozdov I, Gustafsson BI, Modlin IM. Delineation of the chemomechanosensory regulation of gastrin secretion using pure rodent G cells. Gastroenterology 2009; 137:231-41, 241.e1-10. [PMID: 19208342 DOI: 10.1053/j.gastro.2009.01.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 12/12/2008] [Accepted: 01/08/2009] [Indexed: 12/24/2022]
Abstract
BACKGROUND & AIMS Gastrin is a key regulator of gastric acid secretion. We aimed to isolate pure G cells to identify the mechanistic basis of luminal- and strain-mediated regulation. METHODS Using gradient centrifugation and fluorescence-activated cell sorting, rat G cells were prepared and luminal, neural, hormonal, and mechanical activation of secretion and signaling pathways studied. RESULTS Pure G-cell preparations (>97%) were isolated. Reverse-transcription polymerase chain reaction identified neural, hormonal, bacterial, and luminal G protein-coupled receptors, and immunostaining visualized specific sweet/bitter receptors and the tastant-associated G protein alpha-gustducin. Gastrin release was stimulated by forskolin (adenosine 3',5'-cyclic monophosphate [cAMP] inducer, 10 micromol/L; >3-fold), potentiated by 3-isobutyl-1-methylxanthine (IBMX; phosphodiesterase type 5 inhibitor and adenosine antagonist, 10 micromol/L) and phorbol myristate acetate (phorbol ester, 10 micromol/L), and inhibited by H-89 (protein kinase A inhibitor, 10 micromol/L), PD98059 (MEK1 inhibitor, 0.1 micromol/L), and wortmannin (phosphatidylinositol 3-kinase inhibitor, 1 nmol/L). Gastrin release was stimulated by neuronal G protein-coupled receptor ligands, pituitary adenylate cyclase-activating protein (20 pmol/L, >8-fold) and bombesin (0.1 micromol/L, 8-fold) through cAMP signaling. The tastants sucralose, glucose, caffeine, denatonium, and the vanilloid receptor activator capsaicin all stimulated secretion (>3-fold), as did bacterial lipopolysaccharides Salmonella enteritidis (0.24 nmol/L, 5-fold) greater than Helicobacter pylori (0.57 micromol/L, 3-fold). Secretion was associated with elevated cAMP levels (approximately 2-fold) and could be inhibited by H-89 and PD98059 and potentiated by IBMX and cholera toxin (250 microg/mL). Bacterially mediated secretion also involved activation of nuclear factor kappaB and the c-Jun-N-terminal kinase pathway. Mechanical strain stimulated (2-fold to 8-fold) gastrin release, and decreasing pH from 7.4 to 5.5 inhibited release. The adenosine receptor 2B antagonist MRS1754 inhibited mechanically induced gastrin release. CONCLUSIONS G cells are luminal sampling chemomechanosensory cells whose secretion is regulated by neural, hormonal, luminal, and mechanical factors through protein kinase A activation, cAMP signaling, and mitogen-activated protein kinase phosphorylation.
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Affiliation(s)
- Mark Kidd
- Gastrointestinal Pathobiology Research Group, Department of Gastroenterology, Yale University School of Medicine, New Haven, Connecticut 06520-8062, USA
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30
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Goebel J, Forrest K, Wills-Karp M, Roszman TL. Tubulin Polymerization Modulates Interleukin-2 Receptor Signal Transduction in Human T Cells. J Recept Signal Transduct Res 2008; 26:87-106. [PMID: 16595340 DOI: 10.1080/10799890600567372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Few data exist on the modulation of cytokine receptor signaling by the actin or tubulin cytoskeleton. Therefore, we studied interleukin-2 receptor (IL-2R) signaling in phytohemagglutinine (PHA)-pretreated human T cells in the context of alterations in the cytoskeletal system induced by cytochalasin D (CyD), jasplaklinolide (Jas), taxol (Tax), or colchicine (Col). We found that changes in cytoskeletal tubulin polymerization altered the strength of several IL-2-triggered signals. Moreover, Tax-induced tubulin hyperpolymerization augmented the surface expression of the IL-2R ss -chain and enhanced the association of the IL-2R beta -chain with cytoskeletal tubulin. The IL-2R beta-chain, in turn, was constitutively associated with tubulin and, more weakly, actin. To exclude the possibility that these associations are artifacts caused by PHA, we confirmed them in T cells from TCR-transgenic DO 11.10 mice stimulated with their nominal antigen. We conclude that altered polymerization of cytoskeletal components, especially tubulin, is accompanied by modulation of IL-2 signaling at the receptor level.
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Affiliation(s)
- Jens Goebel
- Department of Pediatrics, University of Kentucky, Lexington, Kentucky, USA. Jens.Goebel@cchmc
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31
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Jardin I, Lopez JJ, Salido GM, Rosado JA. Orai1 mediates the interaction between STIM1 and hTRPC1 and regulates the mode of activation of hTRPC1-forming Ca2+ channels. J Biol Chem 2008; 283:25296-25304. [PMID: 18644792 DOI: 10.1074/jbc.m802904200] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Orai1 and hTRPC1 have been presented as essential components of store-operated channels mediating highly Ca(2+) selective I(CRAC) and relatively Ca(2+) selective I(SOC), respectively. STIM1 has been proposed to communicate the Ca(2+) content of the intracellular Ca(2+) stores to the plasma membrane store-operated Ca(2+) channels. Here we present evidence for the dynamic interaction between endogenously expressed Orai1 and both STIM1 and hTRPC1 regulated by depletion of the intracellular Ca(2+) stores, using the pharmacological tools thapsigargin plus ionomycin, or by the physiological agonist thrombin, independently of extracellular Ca(2+). In addition we report that Orai1 mediates the communication between STIM1 and hTRPC1, which is essential for the mode of activation of hTRPC1-forming Ca(2+) permeable channels. Electrotransjection of cells with anti-Orai1 antibody, directed toward the C-terminal region that mediates the interaction with STIM1, and stabilization of an actin cortical barrier with jasplakinolide prevented the interaction between STIM1 and hTRPC1. Under these conditions hTRPC1 was no longer involved in store-operated calcium entry but in diacylglycerol-activated non-capacitative Ca(2+) entry. These findings support the functional role of the STIM1-Orai1-hTRPC1 complex in the activation of store-operated Ca(2+) entry.
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Affiliation(s)
- Isaac Jardin
- Department of Physiology, Cellular Physiology Research Group, University of Extremadura, 10071 Caceres, Spain
| | - José J Lopez
- Department of Physiology, Cellular Physiology Research Group, University of Extremadura, 10071 Caceres, Spain
| | - Gines M Salido
- Department of Physiology, Cellular Physiology Research Group, University of Extremadura, 10071 Caceres, Spain
| | - Juan A Rosado
- Department of Physiology, Cellular Physiology Research Group, University of Extremadura, 10071 Caceres, Spain.
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Kustermans G, Piette J, Legrand-Poels S. Actin-targeting natural compounds as tools to study the role of actin cytoskeleton in signal transduction. Biochem Pharmacol 2008; 76:1310-22. [PMID: 18602087 DOI: 10.1016/j.bcp.2008.05.028] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 05/16/2008] [Indexed: 11/27/2022]
Abstract
Actin cytoskeleton controls a vast range of cellular processes such as motility, cytokinesis, differentiation, vesicle transport, phagocytosis, muscle contraction. A growing literature clearly demonstrated that actin cytoskeleton can play a regulating role in several signalling pathways. Cells tightly regulate actin dynamics through numerous specific proteins in order to rapidly and locally respond to various stimuli. An obvious approach to determine the involvement of actin cytoskeleton in signalling pathways is the use of actin-targeting natural compounds. These drugs modulate actin dynamics, accelerating either polymerization or depolymerization, through various mechanisms. This review focus on the use of these actin-targeting drugs as tools to demonstrate the role of actin cytoskeleton in several signal transduction pathways such as those initiated from antigen receptor in T and B cells or those involving mitogen-activated protein kinases (MAPKs) or transcription factors NF-kappaB and SRF (serum response factor). In this last case (SRF), the use of various actin-targeting drugs participated in the elucidation of the molecular mechanism by which actin regulates SRF-mediated transcription.
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Affiliation(s)
- Gaelle Kustermans
- Virology and Immunology Unit, GIGA-R, GIGA B34, University of Liège, Avenue de l'Hopital 1, B-4000 Liège, Belgium
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Lazarus MD, Schneider TG, Taraschi TF. A new model for hemoglobin ingestion and transport by the human malaria parasite Plasmodium falciparum. J Cell Sci 2008; 121:1937-49. [PMID: 18477610 PMCID: PMC5105679 DOI: 10.1242/jcs.023150] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The current model for hemoglobin ingestion and transport by intraerythrocytic Plasmodium falciparum malaria parasites shares similarities with endocytosis. However, the model is largely hypothetical, and the mechanisms responsible for the ingestion and transport of host cell hemoglobin to the lysosome-like food vacuole (FV) of the parasite are poorly understood. Because actin dynamics play key roles in vesicle formation and transport in endocytosis, we used the actin-perturbing agents jasplakinolide and cytochalasin D to investigate the role of parasite actin in hemoglobin ingestion and transport to the FV. In addition, we tested the current hemoglobin trafficking model through extensive analysis of serial thin sections of parasitized erythrocytes (PE) by electron microscopy. We find that actin dynamics play multiple, important roles in the hemoglobin transport pathway, and that hemoglobin delivery to the FV via the cytostomes might be required for parasite survival. Evidence is provided for a new model, in which hemoglobin transport to the FV occurs by a vesicle-independent process.
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Affiliation(s)
- Michelle D. Lazarus
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy G. Schneider
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Theodore F. Taraschi
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Rabuka D, Forstner MB, Groves JT, Bertozzi CR. Noncovalent cell surface engineering: incorporation of bioactive synthetic glycopolymers into cellular membranes. J Am Chem Soc 2008; 130:5947-53. [PMID: 18402449 DOI: 10.1021/ja710644g] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The controlled addition of structurally defined components to live cell membranes can facilitate the molecular level analysis of cell surface phenomena. Here we demonstrate that cell surfaces can be engineered to display synthetic bioactive polymers at defined densities by exogenous membrane insertion. The polymers were designed to mimic native cell-surface mucin glycoproteins, which are defined by their dense glycosylation patterns and rod-like structures. End-functionalization with a hydrophobic anchor permitted incorporation into the membranes of live cultured cells. We probed the dynamic behavior of cell-bound glycopolymers bearing various hydrophobic anchors and glycan structures using fluorescence correlation spectroscopy (FCS). Their diffusion properties mirrored those of many natural membrane-associated biomolecules. Furthermore, the membrane-bound glycopolymers were internalized into early endosomes similarly to endogenous membrane components and were capable of specific interactions with protein receptors. This system provides a platform to study cell-surface phenomena with a degree of chemical control that cannot be achieved using conventional biological tools.
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Affiliation(s)
- David Rabuka
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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35
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Maluykova I, Gutsal O, Laiko M, Kane A, Donowitz M, Kovbasnjuk O. Latrunculin B facilitates Shiga toxin 1 transcellular transcytosis across T84 intestinal epithelial cells. Biochim Biophys Acta Mol Basis Dis 2008; 1782:370-7. [PMID: 18342638 DOI: 10.1016/j.bbadis.2008.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/23/2008] [Accepted: 01/25/2008] [Indexed: 01/14/2023]
Abstract
Shiga toxins (Stx), released into the intestinal lumen by enterohemorrhagic Escherichia coli (EHEC), are major virulence factors responsible for gastrointestinal and systemic illnesses. These pathologies are believed to be due to the action of the toxins on endothelial cells, which express the Stx receptor, the glycosphingolipid Gb3. To reach the endothelial cells, Stx must translocate across the intestinal epithelial monolayer. This process is poorly understood. We investigated Stx1 movement across the intestinal epithelial T84 cell model and the role of actin turnover in this transcytosis. We showed that changes in the actin cytoskeleton due to latrunculin B, but not cytochalasin D or jasplakinolide, significantly facilitate toxin transcytosis across T84 monolayers. This trafficking is transcellular and completely inhibited by tannic acid, a cell impermeable plasma membrane fixative. This indicates that actin turnover could play an important role in Stx1 transcellular transcytosis across intestinal epithelium in vitro. Since EHEC attachment to epithelial cells causes an actin rearrangement, this finding may be highly relevant to Stx-induced disease.
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Affiliation(s)
- Irina Maluykova
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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36
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Leistner CM, Gruen-Bernhard S, Glebe D. Role of glycosaminoglycans for binding and infection of hepatitis B virus. Cell Microbiol 2007; 10:122-33. [DOI: 10.1111/j.1462-5822.2007.01023.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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37
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Kizhatil K, Davis JQ, Davis L, Hoffman J, Hogan BLM, Bennett V. Ankyrin-G is a molecular partner of E-cadherin in epithelial cells and early embryos. J Biol Chem 2007; 282:26552-61. [PMID: 17620337 DOI: 10.1074/jbc.m703158200] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
E-cadherin is a ubiquitous component of lateral membranes in epithelial tissues and is required to form the first lateral membrane domains in development. Here, we identify ankyrin-G as a molecular partner of E-cadherin and demonstrate that ankyrin-G and beta-2-spectrin are required for accumulation of E-cadherin at the lateral membrane in both epithelial cells and early embryos. Ankyrin-G binds to the cytoplasmic domain of E-cadherin at a conserved site distinct from that of beta-catenin. Ankyrin-G also recruits beta-2-spectrin to E-cadherin-beta-catenin complexes, thus providing a direct connection between E-cadherin and the spectrin/actin skeleton. In addition to restricting the membrane mobility of E-cadherin, ankyrin-G and beta-2-spectrin also are required for exit of E-cadherin from the trans-Golgi network in a microtubule-dependent pathway. Ankyrin-G and beta-2-spectrin co-localize with E-cadherin in preimplantation mouse embryos. Moreover, knockdown of either ankyrin-G or beta-2-spectrin in one cell of a two-cell embryo blocks accumulation of E-cadherin at sites of cell-cell contact. E-cadherin thus requires both ankyrin-G and beta-2-spectrin for its cellular localization in early embryos as well as cultured epithelial cells. We have recently reported that ankyrin-G and beta-2-spectrin collaborate in biogenesis of the lateral membrane ( Kizhatil, K., Yoon, W., Mohler, P. J., Davis, L. H., Hoffman, J. A., and Bennett, V. (2007) J. Biol. Chem. 282, 2029-2037 ). Together with the current findings, these data suggest a ankyrin/spectrin-based mechanism for coordinating membrane assembly with extracellular interactions of E-cadherin at sites of cell-cell contact.
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Affiliation(s)
- Krishnakumar Kizhatil
- Howard Hughes Medical Institute, Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA
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Casartelli M, Corti P, Cermenati G, Grimaldi A, Fiandra L, Santo N, Pennacchio F, Giordana B. Absorption of horseradish peroxidase in Bombyx mori larval midgut. JOURNAL OF INSECT PHYSIOLOGY 2007; 53:517-25. [PMID: 17391693 DOI: 10.1016/j.jinsphys.2007.02.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 02/07/2007] [Accepted: 02/07/2007] [Indexed: 05/14/2023]
Abstract
Increasing experimental evidence indicates that ingested proteins can in part reach the haemocoel undegraded, but information on the mechanisms involved in protein transport across the insect gut is very limited, in spite of the implications that this may have on the development of novel delivery strategies of insecticide proteins targeting haemocoelic receptors. Here we contribute to this field of study, by focusing on horseradish peroxidase (HRP) transport through Bombyx mori larval midgut, isolated and perfused in vitro. The protein crossed the intestinal barrier in a time-dependent manner and the influx was linearly related to time between 30 and 90 min of incubation. HRP absorption was strongly affected by temperature and inhibition of cell metabolism: protein influx at 4 degrees C was reduced to 27% of that measured at 25 degrees C and was similarly inhibited by the metabolic inhibitor DNP. Transmission electron microscopy analysis of midgut columnar cells exposed to HRP showed the presence of the protein both in vesicular structures inside the cytoplasm and in the space between two adjacent absorptive cells, indicating the occurrence of both a transcellular and a paracellular permeation route. The analysis of HRP influx as a function of increasing protein concentration in the lumen supported this morphological indication. The J(max) relative to the HRP transcellular transport component was 121+/-24 pmol/cm(2)/h and the K(d) of the passage through the paracellular route was 1.9+/-0.3 microl/cm(2)/h. The paracellular electrical resistance decreased in midguts exposed to HRP, indicating that its passage through this pathway was likely due to an alteration exerted on the junctional complex by the protein itself. The role of the cytoskeleton in HRP transport was investigated by assessing the impact of drugs affecting microtubules and actin filaments.
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Affiliation(s)
- Morena Casartelli
- Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy.
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Murakoshi M, Gomi T, Iida K, Kumano S, Tsumoto K, Kumagai I, Ikeda K, Kobayashi T, Wada H. Imaging by atomic force microscopy of the plasma membrane of prestin-transfected Chinese hamster ovary cells. J Assoc Res Otolaryngol 2006; 7:267-78. [PMID: 16761115 PMCID: PMC2504612 DOI: 10.1007/s10162-006-0041-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2005] [Accepted: 04/26/2006] [Indexed: 11/27/2022] Open
Abstract
The high sensitivity of mammalian hearing is achieved by amplification of the motion of the cochlear partition. This cochlear amplification is thought to be generated by the elongation and contraction of outer hair cells (OHCs) in response to acoustical stimulation. This motility is made possible by a membrane protein embedded in the lateral membrane of OHCs. Although a fructose transporter, GLUT-5, was initially proposed to be this protein, a later study identified the gene of the motor protein distributed throughout the OHC plasma membrane. This protein has been named "prestin." However, although previous morphological studies by electron microscopy and atomic force microscopy (AFM) found the lateral wall of OHCs to be covered with 10-nm particles, believed to be motor proteins, it is unknown whether such particles consist only of prestin or are a complex of GLUT-5 and prestin molecules. To determine if the 10-nm particles are indeed constituted only of prestin, plasma membranes of prestin-transfected and untransfected Chinese hamster ovary (CHO) cells, which do not express GLUT-5, were observed by AFM. First, the cells attached to a substrate were sonicated so that only the plasma membrane remained on the substrate. The cytoplasmic face of the cell was observed by the tapping mode of the AFM in liquid. As a result, particle-like structures were recognized on the plasma membranes of both the prestin-transfected and untransfected CHO cells. Comparison of the difference in the frequency distribution of these structures between those two cells showed approximately 75% of the particle-like structures with a diameter of 8-12 nm in the prestin-transfected CHO cells to be possibly constituted only by prestin molecules. Our data suggest that the densely packed 10-nm particles observed on the OHC lateral wall are likely to be constituted only of prestin molecules.
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Affiliation(s)
- Michio Murakoshi
- Department of Bioengineering and Robotics, Tohoku University, 6-6-01 Aoba-yama, Sendai, 980-8579 Japan
| | - Takashi Gomi
- Department of Bioengineering and Robotics, Tohoku University, 6-6-01 Aoba-yama, Sendai, 980-8579 Japan
| | - Koji Iida
- Department of Bioengineering and Robotics, Tohoku University, 6-6-01 Aoba-yama, Sendai, 980-8579 Japan
| | - Shun Kumano
- Department of Bioengineering and Robotics, Tohoku University, 6-6-01 Aoba-yama, Sendai, 980-8579 Japan
| | - Kouhei Tsumoto
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8652 Japan
| | - Izumi Kumagai
- Department of Biomolecular Engineering, Tohoku University, 6-6-11 Aoba-yama, Sendai, 980-8579 Japan
| | - Katsuhisa Ikeda
- Department of Otorhinolaryngology, Juntendo University School of Medicine, 2-1-1 Hongo, Tokyo, 113-8421 Japan
| | - Toshimitsu Kobayashi
- Department of Otorhinolaryngology–Head and Neck Surgery, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Sendai, 980-8574 Japan
| | - Hiroshi Wada
- Department of Bioengineering and Robotics, Tohoku University, 6-6-01 Aoba-yama, Sendai, 980-8579 Japan
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Ahtiainen L, Luiro K, Kauppi M, Tyynelä J, Kopra O, Jalanko A. Palmitoyl protein thioesterase 1 (PPT1) deficiency causes endocytic defects connected to abnormal saposin processing. Exp Cell Res 2006; 312:1540-53. [PMID: 16542649 DOI: 10.1016/j.yexcr.2006.01.034] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 01/17/2006] [Accepted: 01/18/2006] [Indexed: 11/16/2022]
Abstract
Infantile neuronal ceroid lipofuscinosis (INCL) is a severe neurodegenerative disorder of the childhood caused by mutations in the gene encoding palmitoyl protein thioesterase 1 (PPT1). PPT1 localizes to late endosomes/lysosomes of non-neuronal cells and in neurons also to presynaptic areas. PPT1-deficiency causes massive death of cortical neurons and most tissues show an accumulation of saposins A and D. We have here studied endocytic pathways, saposin localization and processing in PPT1-deficient fibroblasts to elucidate the cellular defects resulting in accumulation of specific saposins. We show that PPT1-deficiency causes a defect in fluid-phase and receptor-mediated endocytosis, whereas marker uptake and recycling endocytosis remain intact. Furthermore, we show that saposins A and D are more abundant and relocalized in PPT-deficient fibroblasts and mouse primary neurons. Metabolic labeling and immunoprecipitation analyses revealed hypersecretion and abnormal processing of prosaposin, implying that the accumulation of saposins may result from endocytic defects. We show for the first time a connection between saposin storage and a defect in the endocytic pathway of INCL cells. These data provide new insights into the metabolism of PPT1-deficient cells and offer a basis for further studies on cellular processes causing neuronal death in INCL and other neurodegenerative diseases.
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Affiliation(s)
- Laura Ahtiainen
- National Public Health Institute, Department of Molecular Medicine, Biomedicum Helsinki, P.O. Box 104, 00251 Helsinki, Finland
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Watson CJ, Hoare CJ, Garrod DR, Carlson GL, Warhurst G. Interferon-gamma selectively increases epithelial permeability to large molecules by activating different populations of paracellular pores. J Cell Sci 2005; 118:5221-30. [PMID: 16249235 DOI: 10.1242/jcs.02630] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Impairment of the gut epithelial barrier by agents such as IFNgamma may play a key role in the pathogenesis of inflammatory disorders by increasing the paracellular penetration of luminal macromolecules, potentially including bacterial antigens. Owing to limitations of current paracellular probes, little is known about the precise functional changes induced by IFNgamma and how these relate to the development of increased macromolecular permeability. Here we investigate how IFNgamma modulates this pathway in T84 monolayers using a novel profiling technique that resolves different populations of paracellular pores by simultaneous analysis of 24 permeability probes of defined molecular size. Two types of functional pore present in control monolayers, an abundant restrictive pore with a radius of approximately 4.5 Angstrom and a much larger but infrequent, non-restrictive pore, were differentially regulated by IFNgamma. Incubation with IFNgamma dose-dependently and reversibly increased the frequency of the non-restrictive pores while having no significant effect on the restrictive component. Cytokine-induced increases in beta, the descriptor of the non-restrictive pore, correlated closely with increased permeability to large molecules (10 kDa) including E. coli-derived lipopolysaccharide, but not small (0.182 kDa) molecules. This effect was associated with changes in expression of the tight junction proteins occludin and claudin-1. These data suggest that IFNgamma selectively increases the transepithelial flux of large molecules by activating specific pathways within the junctional pore. One hypothesis is that this process may be activated in the early stages of the inflammatory response, facilitating the passage of large and potentially antigenic molecules across the gut without gross disruption of the barrier to small molecules.
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Affiliation(s)
- Christopher J Watson
- Gut Barrier Group, Injury Research, Salford Royal Hospitals NHS Trust and Faculty of Medicine and Human Sciences, University of Manchester, Clinical Sciences Building, Hope Hospital, Salford, M6 8HD, UK
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Laskarin G, Cupurdija K, Tokmadzic VS, Dorcic D, Dupor J, Juretic K, Strbo N, Crncic TB, Marchezi F, Allavena P, Mantovani A, Randic L, Rukavina D. The presence of functional mannose receptor on macrophages at the maternal-fetal interface. Hum Reprod 2005; 20:1057-66. [PMID: 15746201 DOI: 10.1093/humrep/deh740] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The mannose receptor (MR) is involved in the initiation of the immune response and regulation of homeostasis during inflammation and tissue remodeling. METHODS Distribution, endocytosis and possible natural ligand tumor associated glycoprotein-72 (TAG-72) for the MR have been examined by immunohistology, immunocytochemistry and flow cytometry at the maternal-fetal interface, characterized by extensive tissue remodeling. RESULTS Contrary to disseminated distribution of the MR positive (MR+) cells in term placenta, the MR+ cells of early pregnancy decidua intimately surrounded glands and followed tissue distribution of CD14 positive cells. The mannose receptor was present on freshly isolated first trimester decidual mononuclear cells and distributed mostly on macrophages (77.08 +/- 10.55%, mean +/- SD). The expression of the MR on CD14 positive cells decreased following 18 h culture (P < 0.01) and was accompanied by the reduction of fluorescein isothiocyanate (FITC)-dextran uptake. PAM-1 anti-MR antibody, mannan and TAG-72 reduced FITC-dextran uptake by decidual macrophages. CONCLUSIONS These data indicate that the MR+ macrophages, surrounding early decidual glands, are able to internalize ligands for carbohydrate recognition domain of the receptor, including decidual secretory phase mucin TAG-72.
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Affiliation(s)
- G Laskarin
- Department of Physiology and Immunology, School of Medicine, University of Rijeka, B. Branchetta 20/1, 51000 Rijeka, Croatia.
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Bloch D, Lavy M, Efrat Y, Efroni I, Bracha-Drori K, Abu-Abied M, Sadot E, Yalovsky S. Ectopic expression of an activated RAC in Arabidopsis disrupts membrane cycling. Mol Biol Cell 2005; 16:1913-27. [PMID: 15703216 PMCID: PMC1073671 DOI: 10.1091/mbc.e04-07-0562] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rho GTPases regulate the actin cytoskeleton, exocytosis, endocytosis, and other signaling cascades. Rhos are subdivided into four subfamilies designated Rho, Racs, Cdc42, and a plant-specific group designated RACs/Rops. This research demonstrates that ectopic expression of a constitutive active Arabidopsis RAC, AtRAC10, disrupts actin cytoskeleton organization and membrane cycling. We created transgenic plants expressing either wild-type or constitutive active AtRAC10 fused to the green fluorescent protein. The activated AtRAC10 induced deformation of root hairs and leaf epidermal cells and was primarily localized in Triton X-100-insoluble fractions of the plasma membrane. Actin cytoskeleton reorganization was revealed by creating double transgenic plants expressing activated AtRAC10 and the actin marker YFP-Talin. Plants were further analyzed by membrane staining with N-[3-triethylammoniumpropyl]-4-[p-diethylaminophenylhexatrienyl] pyridinium dibromide (FM4-64) under different treatments, including the protein trafficking inhibitor brefeldin A or the actin-depolymeryzing agents latrunculin-B (Lat-B) and cytochalasin-D (CD). After drug treatments, activated AtRAC10 did not accumulate in brefeldin A compartments, but rather reduced their number and colocalized with FM4-64-labeled membranes in large intracellular vesicles. Furthermore, endocytosis was compromised in root hairs of activated AtRAC10 transgenic plants. FM4-64 was endocytosed in nontransgenic root hairs treated with the actin-stabilizing drug jasplakinolide. These findings suggest complex regulation of membrane cycling by plant RACs.
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Affiliation(s)
- Daria Bloch
- Department of Plant Sciences, Tel Aviv University, Israel
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Watts BA, George T, Good DW. The basolateral NHE1 Na+/H+ exchanger regulates transepithelial HCO3- absorption through actin cytoskeleton remodeling in renal thick ascending limb. J Biol Chem 2005; 280:11439-47. [PMID: 15644322 DOI: 10.1074/jbc.m410719200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the renal medullary thick ascending limb (MTAL), inhibiting the basolateral NHE1 Na(+)/H(+) exchanger with amiloride or nerve growth factor (NGF) results secondarily in inhibition of the apical NHE3 Na(+)/H(+) exchanger, thereby decreasing transepithelial HCO3- absorption. MTALs from rats were studied by in vitro microperfusion to identify the mechanism underlying cross-talk between the two exchangers. The basolateral addition of 10 microM amiloride or 0.7 nM NGF decreased HCO3- absorption by 27-32%. Jasplakinolide, which stabilizes F-actin, or latrunculin B, which disrupts F-actin, decreased basal HCO3- absorption by 30% and prevented the inhibition by amiloride or NGF. Jasplakinolide had no effect on HCO3- absorption in tubules bathed with amiloride or a Na(+)-free bath to inhibit NHE1. Jasplakinolide and latrunculin B did not prevent inhibition of HCO3- absorption by vasopressin or stimulation by hyposmolality, factors that regulate HCO3- absorption through primary effects on apical Na(+)/H(+) exchange. Treatment of MTALs with amiloride or NGF for 15 min decreased polymerized actin with no change in total cell actin, as assessed both by fluorescence microscopy and by actin Triton X-100 solubility. Jasplakinolide prevented amiloride-induced actin remodeling. Vasopressin, which inhibits HCO3- absorption by an amount similar to that observed with amiloride and NGF but does not act via NHE1, did not affect cellular F-actin content. These results indicate that basolateral NHE1 regulates apical NHE3 and HCO3- absorption in the MTAL by controlling the organization of the actin cytoskeleton.
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Affiliation(s)
- Bruns A Watts
- Department of Medicine, University of Texas Medical Branch, Galveston, Texas 77555-0562, USA
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Beaulieu V, Da Silva N, Pastor-Soler N, Brown CR, Smith PJS, Brown D, Breton S. Modulation of the actin cytoskeleton via gelsolin regulates vacuolar H+-ATPase recycling. J Biol Chem 2004; 280:8452-63. [PMID: 15591047 DOI: 10.1074/jbc.m412750200] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The role of the actin cytoskeleton in regulating membrane protein trafficking is complex and depends on the cell type and protein being examined. Using the epididymis as a model system in which luminal acidification is crucial for sperm maturation and storage, we now report that modulation of the actin cytoskeleton by the calcium-activated actin-capping and -severing protein gelsolin plays a key role in regulating vacuolar H(+)-ATPase (V-ATPase) recycling. Epididymal clear cells contain abundant V-ATPase in their apical pole, and an increase in their cell-surface V-ATPase expression correlates with an increase in luminal proton secretion. We have shown that apical membrane accumulation of V-ATPase is triggered by an elevation in cAMP following activation of bicarbonate-regulated soluble adenylyl cyclase in response to alkaline luminal pH (Pastor-Soler, N., Beaulieu, V., Litvin, T. N., Da Silva, N., Chen, Y., Brown, D., Buck, J., Levin, L. R., and Breton, S. (2003) J. Biol. Chem. 278, 49523-49529). Here, we show that clear cells express high levels of gelsolin, indicating a potential role in the functional activity of these cells. When jasplakinolide was used to overcome the severing action of gelsolin by polymerizing actin, complete inhibition of the alkaline pH- and cAMP-induced apical membrane accumulation of V-ATPase was observed. Conversely, when gelsolin-mediated actin filament elongation was inhibited using a 10-residue peptide (PBP10) derived from the phosphatidylinositol 4,5-bisphosphate-binding region (phosphoinositide-binding domain 2) of gelsolin, significant V-ATPase apical membrane mobilization was induced, even at acidic luminal pH. In contrast, the calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) and the phospholipase C inhibitor U-73122 inhibited the alkaline pH-induced V-ATPase apical accumulation. Thus, maintenance of the actin cytoskeleton in a depolymerized state by gelsolin facilitates calcium-dependent apical accumulation of V-ATPase in response to luminal pH alkalinization. Gelsolin is present in other cell types that express the V-ATPase in their plasma membrane and recycling vesicles, including kidney intercalated cells and osteoclasts. Therefore, modulation of the actin cortex by this severing and capping protein may represent a common mechanism by which these cells regulate their rate of proton secretion.
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Affiliation(s)
- Valérie Beaulieu
- Program in Membrane Biology, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
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Campo C, Mason A, Maouyo D, Olsen O, Yoo D, Welling PA. Molecular mechanisms of membrane polarity in renal epithelial cells. Rev Physiol Biochem Pharmacol 2004; 153:47-99. [PMID: 15674648 DOI: 10.1007/s10254-004-0037-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Exciting discoveries in the last decade have cast light onto the fundamental mechanisms that underlie polarized trafficking in epithelial cells. It is now clear that epithelial cell membrane asymmetry is achieved by a combination of intracellular sorting operations, vectorial delivery mechanisms and plasmalemma-specific fusion and retention processes. Several well-defined signals that specify polarized segregation, sorting, or retention processes have, now, been described in a number of proteins. The intracellular machineries that decode and act on these signals are beginning to be described. In addition, the nature of the molecules that associate with intracellular trafficking vesicles to coordinate polarized delivery, tethering, docking, and fusion are also becoming understood. Combined with direct visualization of polarized sorting processes with new technologies in live-cell fluorescent microscopy, new and surprising insights into these once-elusive trafficking processes are emerging. Here we provide a review of these recent advances within an historically relevant context.
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Affiliation(s)
- C Campo
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Baluska F, Samaj J, Hlavacka A, Kendrick-Jones J, Volkmann D. Actin-dependent fluid-phase endocytosis in inner cortex cells of maize root apices. JOURNAL OF EXPERIMENTAL BOTANY 2004; 55:463-473. [PMID: 14739268 DOI: 10.1093/jxb/erh042] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The fluorescent dye Lucifer Yellow (LY) is a well-known and widely-used marker for fluid-phase endocytosis. In this paper, both light and electron microscopy revealed that LY was internalized into transition zone cells of the inner cortex of intact maize root apices. The internalized LY was localized within tubulo-vesicular compartments invaginating from the plasma membrane at actomyosin-enriched pit-fields and individual plasmodesmata, as well as within adjacent small peripheral vacuoles. The internalization of LY was blocked by pretreating the roots with the F-actin depolymerizing drug latrunculin B, but not with the F-actin stabilizer jasplakinolide. F-actin enriched plasmodesmata and pit-fields of the inner cortex also contain abundant plant-specific unconventional class VIII myosin(s). In addition, 2,3 butanedione monoxime, a general inhibitor of myosin ATPases, partially inhibited the uptake of LY into cells of the inner cortex. Conversely, loss of microtubules did not inhibit fluid-phase endocytosis of LY into these cells. In conclusion, specialized actin- and myosin VIII-enriched membrane domains perform a tissue-specific form of fluid-phase endocytosis in maize root apices. The possible physiological relevance of this process is discussed.
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Affiliation(s)
- F Baluska
- Institute of Cellular and Molecular Botany, Rheinische Friedrich-Wilhelms-Universität Bonn, Kirschallee 1, D-53115 Bonn, Germany.
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Abstract
Actin and its associated proteins participate in several intracellular trafficking mechanisms. This review assesses recent work that shows how actin participates in the terminal trafficking event of membrane bilayer fusion. A recent flurry of reports defines a role for Rho proteins in membrane fusion and also demonstrates that this role is distinct from any vesicle transport mechanism. Rho proteins are well known to govern actin remodeling, which implicates this process as a condition of membrane fusion. A small but significant body of work examines actin-regulated events of intracellular membrane fusion, exocytosis and endocytosis. In general, actin has been shown to act as a negative regulator of exocytosis. Cortical actin filaments act as a barrier that requires transient removal to allow vesicles to undergo docking at the plasma membrane. However, once docked, F-actin synthesis may act as a positive regulator to give the final stimulus to drive membrane fusion. F-actin synthesis is clearly needed for endocytosis and intracellular membrane fusion events. What may seem like dissimilar results are perhaps snapshots of a single mechanism of membranous actin remodeling (i.e. dynamic disassembly and reassembly) that is universally needed for all membrane fusion events.
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Affiliation(s)
- Gary Eitzen
- Department of Cell Biology, MSB 5-14, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
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Ikonomov OC, Sbrissa D, Foti M, Carpentier JL, Shisheva A. PIKfyve controls fluid phase endocytosis but not recycling/degradation of endocytosed receptors or sorting of procathepsin D by regulating multivesicular body morphogenesis. Mol Biol Cell 2003; 14:4581-91. [PMID: 14551253 PMCID: PMC266774 DOI: 10.1091/mbc.e03-04-0222] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The mammalian phosphatidylinositol (PtdIns) 5-P/PtdIns 3,5-P2-producing kinase PIKfyve has been implicated in maintaining endomembrane homeostasis in mammalian cells. To address the role of PIKfyve in trafficking processes, we examined the functioning of the biosynthetic, endocytic, and recycling pathways in stable human embryonic kidney 293 cell lines inducibly expressing the wild-type or kinase-defective dominant-negative form. PIKfyveWT or PIKfyveK1831E expression did not affect the processing and lysosomal targeting of newly synthesized procathepsin D. Likewise the rates of transferrin uptake/recycling or epidermal growth factor receptor degradation were not altered upon expression of either protein. In contrast, PIKfyveK1831E but not PIKfyveWT expression markedly impaired the late uptake of fluid phase marker horseradish peroxidase. Inspection of the organelle morphology by confocal microscopy with specific markers in COS cells transiently expressing PIKfyveK1831E showed the Golgi apparatus, end lysosomes, and the recycling compartment indistinguishable from nontransfected cells, despite the dramatic PIKfyveK1831E-induced endomembrane vacuolation. In contrast, we observed a striking effect on the late endocytic compartment, marked by disruption of the dextran-labeled perinuclear endosomal compartment and formation of dispersed enlarged vesicles. Electron microscopy identified the cytoplasmic vacuoles in the PIKfyveK1831E-expressing human embryonic kidney 293 cells as enlarged multivesicular body-like structures with substantially lower number of internal vesicles and membrane whorls. Together, these data indicate that PIKfyve selectively regulates the sorting and traffic of peripheral endosomes containing lysosomaly directed fluid phase cargo through controlling the morphogenesis and function of multivesicular bodies.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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50
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Abstract
In this review we describe the potential roles of the actin cytoskeleton in receptor-mediated endocytosis in mammalian cells and summarize the efforts of recent years in establishing a relationship between these two cellular functions. With molecules such as dynamin, syndapin, HIP1R, Abp1, synaptojanin, N-WASP, intersectin, and cortactin a set of molecular links is now available and it is likely that their further characterization will reveal the basic principles of a functional interconnection between the membrane cytoskeleton and the vesicle-budding machinery. We will therefore discuss proteins involved in endocytic clathrin coat formation and accessory factors to control and regulate coated vesicle formation but we will also focus on actin cytoskeletal components such as the Arp2/3 complex, spectrin, profilin, and motor proteins involved in actin dynamics and organization. Additionally, we will discuss how phosphoinositides, such as PI(4,5)P2, small GTPases thought to control the actin cytoskeleton, such as Rho, Rac, and Cdc42, or membrane trafficking, such as Rab GTPases and ARF proteins, and different kinases may participate in the functional connection of actin and endocytosis. We will compare the concepts and different molecular mechanisms involved in mammalian cells with yeast as well as with specialized cells, such as epithelial cells and neurons, because different model organisms often offer complementary advantages for further studies in this thriving field of current cell biological research.
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Affiliation(s)
- Britta Qualmann
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
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