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Macropinocytosis

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https://www.readbyqxmd.com/read/28637475/uptake-of-label-free-graphene-oxide-by-caco-2-cells-is-dependent-on-the-cell-differentiation-status
#1
Melanie Kucki, Liliane Diener, Nils Bohmer, Cordula Hirsch, Harald F Krug, Vincenzo Palermo, Peter Wick
BACKGROUND: Understanding the interaction of graphene-related materials (GRM) with human cells is a key to the assessment of their potential risks for human health. There is a knowledge gap regarding the potential uptake of GRM by human intestinal cells after unintended ingestion. Therefore the aim of our study was to investigate the interaction of label-free graphene oxide (GO) with the intestinal cell line Caco-2 in vitro and to shed light on the influence of the cell phenotype given by the differentiation status on cellular uptake behaviour...
June 21, 2017: Journal of Nanobiotechnology
https://www.readbyqxmd.com/read/28634138/intracellular-and-transdermal-protein-delivery-mediated-by-non-covalent-interactions-with-a-synthetic-guanidine-rich-molecular-carrier
#2
Jungkyun Im, Sanket Das, Dongjun Jeong, Chang-Jin Kim, Hyun-Suk Lim, Ki Hean Kim, Sung-Kee Chung
The impermeability of the cell plasma membrane is one of the major barriers for protein transduction into mammalian cells, and it also limits the use of proteins as therapeutic agents. Protein transduction has usually been achieved based on certain invasive processes or cell penetrating peptides (CPP). Herein we report our study in which a synthetic guanidine-rich molecular carrier is used as a delivery vector for intracellular and transdermal delivery of proteins. First a sorbitol-based molecular carrier having 8 guanidine units (Sor-G8) was synthesized, and then was simply mixed with a cargo protein of varying sizes to form the non-covalent complex of carrier-cargo proteins...
June 17, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28630093/dendritic-cell-sensing-of-hydrophobic-di-and-triacylated-lipopeptides-self-assembled-within-synthetic-virus-like-particles
#3
Rajni Sharma, Arin Ghasparian, John A Robinson, Kenneth C McCullough
Dendritic cells (DCs) play critical roles in developing immune defenses. One important aspect is interaction with pathogen-associated molecular patterns (PAMPs)/danger-associated molecular patterns, including di- and triacylated lipopeptides. Isolated or synthetic lipopeptides are potent vaccine adjuvants, interacting with cell surface TLR2 heterodimers. In contrast, deep embedment within bacteria cell walls would impair lipopeptide interaction with cell surface TLR2, requiring degradation for PAMP recognition...
June 19, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28627511/fronts-and-waves-of-actin-polymerization-in-a-bistability-based-mechanism-of-circular-dorsal-ruffles
#4
Erik Bernitt, Hans-Günther Döbereiner, Nir S Gov, Arik Yochelis
During macropinocytosis, cells remodel their morphologies for the uptake of extracellular matter. This endocytotic mechanism relies on the collapse and closure of precursory structures, which are propagating actin-based, ring-shaped vertical undulations at the dorsal (top) cell membrane, a.k.a. circular dorsal ruffles (CDRs). As such, CDRs are essential to a range of vital and pathogenic processes alike. Here we show, based on both experimental data and theoretical analysis, that CDRs are propagating fronts of actin polymerization in a bistable system...
June 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28619714/the-g-protein-coupled-receptor-gpr31-promotes-membrane-association-of-kras
#5
Nicole Fehrenbacher, Israel Tojal da Silva, Craig Ramirez, Yong Zhou, Kwang-Jin Cho, Shafi Kuchay, Jie Shi, Susan Thomas, Michele Pagano, John F Hancock, Dafna Bar-Sagi, Mark R Philips
The product of the KRAS oncogene, KRAS4B, promotes tumor growth when associated with the plasma membrane (PM). PM association is mediated, in part, by farnesylation of KRAS4B, but trafficking of nascent KRAS4B to the PM is incompletely understood. We performed a genome-wide screen to identify genes required for KRAS4B membrane association and identified a G protein-coupled receptor, GPR31. GPR31 associated with KRAS4B on cellular membranes in a farnesylation-dependent fashion, and retention of GPR31 on the endoplasmic reticulum inhibited delivery of KRAS4B to the PM...
June 15, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28607485/exosomes-facilitate-therapeutic-targeting-of-oncogenic-kras-in-pancreatic-cancer
#6
Sushrut Kamerkar, Valerie S LeBleu, Hikaru Sugimoto, Sujuan Yang, Carolina F Ruivo, Sonia A Melo, J Jack Lee, Raghu Kalluri
The mutant form of the GTPase KRAS is a key driver of pancreatic cancer but remains a challenging therapeutic target. Exosomes are extracellular vesicles generated by all cells, and are naturally present in the blood. Here we show that enhanced retention of exosomes, compared to liposomes, in the circulation of mice is likely due to CD47-mediated protection of exosomes from phagocytosis by monocytes and macrophages. Exosomes derived from normal fibroblast-like mesenchymal cells were engineered to carry short interfering RNA or short hairpin RNA specific to oncogenic Kras(G12D), a common mutation in pancreatic cancer...
June 22, 2017: Nature
https://www.readbyqxmd.com/read/28596575/infectious-pancreatic-necrosis-virus-enters-chse-214-cells-via-macropinocytosis
#7
Jorge Levican, Camila Miranda-Cárdenas, Ricardo Soto-Rifo, Francisco Aguayo, Aldo Gaggero, Oscar León
Infectious pancreatic necrosis virus (IPNV) is a non-enveloped virus belonging to the Birnaviridae family. IPNV produces an acute disease in salmon fingerlings, with high mortality rates and persistent infection in survivors. Although there are reports of IPNV binding to various cells, the viral receptor and entry pathways remain unknown. The aim of this study was to determine the endocytic pathway that allows for IPNV entry. We observed that IPNV stimulated fluid uptake and virus particles co-localysed with the uptake marker dextran in intracellular compartments, suggesting a role for macropinocytosis in viral entry...
June 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28590839/contractility-differential-tension-and-membrane-removal-lead-zebrafish-epiboly-biomechanics
#8
Maria Marsal, Amayra Hernández-Vega, Enrique Martin-Blanco
Precise tissue remodeling during development is essential for shaping embryos and optimal organ function. Epiboly is an early gastrulation event by which the blastoderm expands around the yolk to engulf it. Three different layers are involved in this process, an epithelial layer (the enveloping layer, EVL), the embryo proper, constituted by the deep cells (DCs), and the yolk cell. Although teleost epiboly has been studied for many years, a clear understanding of its mechanics was still missing. Here we present new information on the cellular, molecular and mechanical elements involved in epiboly that, together with some other recent data and upon comparison with previous biomechanical models, lets conclude that the expansion of the epithelia is passive and driven by active cortical contraction and membrane removal in the adjacent layer, the External Yolk Syncytial Layer (E-YSL)...
June 7, 2017: Cell Cycle
https://www.readbyqxmd.com/read/28579780/aggregation-is-a-critical-cause-of-poor-transfer-into-the-brain-tissue-of-intravenously-administered-cationic-pamam-dendrimer-nanoparticles
#9
Yoshika Kurokawa, Hideko Sone, Tin-Tin Win-Shwe, Yang Zeng, Hiroyuki Kimura, Yosuke Koyama, Yusuke Yagi, Yasuto Matsui, Masashi Yamazaki, Seishiro Hirano
Dendrimers have been expected as excellent nanodevices for brain medication. An amine-terminated polyamidoamine dendrimer (PD), an unmodified plain type of PD, has the obvious disadvantage of cytotoxicity, but still serves as an attractive molecule because it easily adheres to the cell surface, facilitating easy cellular uptake. Single-photon emission computed tomographic imaging of a mouse following intravenous injection of a radiolabeled PD failed to reveal any signal in the intracranial region. Furthermore, examination of the permeability of PD particles across the blood-brain barrier (BBB) in vitro using a commercially available kit revealed poor permeability of the nanoparticles, which was suppressed by an inhibitor of caveolae-mediated endocytosis, but not by an inhibitor of macropinocytosis...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/28576417/low-concentrations-of-neutrophil-extracellular-traps-induce-proliferation-in-human-keratinocytes-via-nf-kb-activation
#10
Stelvio Tonello, Manuela Rizzi, Mario Migliario, Vincenzo Rocchetti, Filippo Renò
INTRODUCTION: Granulocytes play a pivotal role in innate immune response, as pathogen invasion activates neutrophils, a subclass of granulocytes, inducing the production of neutrophil extracellular traps (NETs). In this study, it has been evaluated how NETs could affect human keratinocytes (HaCaT cells) behaviour. MATERIALS AND METHODS: HaCaT cells were treated with increasing NETs concentrations (0.01-200ng/ml) and the effect on cell proliferation was evaluated by MTT assay...
May 23, 2017: Journal of Dermatological Science
https://www.readbyqxmd.com/read/28572516/jaspine-b-induces-non-apoptotic-cell-death-in-gastric-cancer-cells-independently-of-its-inhibition-of-ceramide-synthase
#11
Francesca Cingolani, Fabio Simbari, Jose Luis Abad, Mireia Casasampere, Gemma Fabrias, Anthony H Futerman, Josefina Casas
Sphingolipids have been extensively investigated in biomedical research due to their role as bioactive molecules in cells. Here we describe the effect of a sphingolipid analogue, Jaspine B (JB), a cyclic anhydrophytosphingosine found in marine sponges, on the gastric cancer cell line HGC-27. JB induces alterations in the sphingolipidome, mainly the accumulation of dihydrosphingosine (dhSo) and sphingosine (So), and their phosphorylated forms, due to inhibition of ceramide synthases (CerS). Moreover, JB induces atypical cell death in HGC-27 cells, characterized by the formation of cytoplasmic vacuoles in a time and dose-dependent manner...
June 1, 2017: Journal of Lipid Research
https://www.readbyqxmd.com/read/28559042/self-assembled-core-shell-type-lipid-polymer-hybrid-nanoparticles-intracellular-trafficking-and-relevance-for-oral-absorption
#12
Qiuxia Li, Dengning Xia, Jinsong Tao, Aijun Shen, Yuan He, Yong Gan, Chi Wang
Lipid-polymer hybrid nanoparticles (NPs) are advantageous for drug delivery. However, their intracellular trafficking mechanism and relevance for oral drug absorption are poorly understood. In this study, self-assembled core-shell lipid-polymer hybrid NPs made of PLGA and various lipids were developed to study their differing intracellular trafficking in intestinal epithelial cells, and their relevance for oral absorption of a model drug saquinavir (SQV). Our results demonstrated that the endocytosis and exocytosis of hybrid NPs could be changed by varying the kind of lipid...
May 27, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28544479/drinking-problems-mechanisms-of-macropinosome-formation-and-maturation
#13
REVIEW
Catherine M Buckley, Jason S King
Macropinocytosis is a mechanism for the non-specific bulk uptake and internalisation of extracellular fluid. This plays specific and distinct roles in diverse cell types such as macrophages, dendritic cells and neurons, by allowing cells to sample their environment, extract extracellular nutrients and regulate plasma membrane turnover. Macropinocytosis has recently been implicated in several diseases including cancer, neurodegenerative diseases and atherosclerosis. Uptake by macropinocytosis is also exploited by several intracellular pathogens to gain entry into host cells...
May 24, 2017: FEBS Journal
https://www.readbyqxmd.com/read/28526602/palmitoyl-ascorbate-and-doxorubicin-co-encapsulated-liposome-for-synergistic-anticancer-therapy
#14
Yue Yang, Xiaoyu Lu, Qi Liu, Yu Dai, Xiaojie Zhu, Yanli Wen, Jiaqiu Xu, Yang Lu, Di Zhao, Xijing Chen, Ning Li
Combination therapy with two drugs and nanoparticle-based drug delivery systems are widely applied to reduce the adverse effects of traditional treatment by chemotherapeutic drugs. Palmitoyl ascorbate (PA) as a lipophilic derivative of ascorbic acid shows the advantages in cancer treatment. The aim of the study was to prepare a doxorubicin (DOX) and PA co-loaded liposome to synergistically treat tumor and effectively alleviate the toxicity caused by DOX. The effects were evaluated by in vitro and in vivo studies...
May 17, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28524754/arf-gtpase-interplay-with-rho-gtpases-in-regulation-of-the-actin-cytoskeleton
#15
Vikash Singh, Anthony C Davidson, Peter J Hume, Daniel Humphreys, Vassilis Koronakis
The Arf and Rho subfamilies of small GTPases are nucleotide-dependent molecular switches that act as master regulators of vesicular trafficking and the actin cytoskeleton organization. Small GTPases control cell processes with high fidelity by acting through distinct repertoires of binding partners called effectors. While we understand a great deal about how these GTPases act individually, relatively little is known about how they cooperate, especially in the control of effectors. This review highlights how Arf GTPases collaborate with Rac1 to regulate actin cytoskeleton dynamics at the membrane via recruiting and activating the Wave Regulatory Complex (WRC), a Rho effector that underpins lamellipodia formation and macropinocytosis...
May 19, 2017: Small GTPases
https://www.readbyqxmd.com/read/28522588/a-potential-mechanism-for-adc-induced-neutropenia-role-of-neutrophils-in-their-own-demise
#16
Hui Zhao, Sara Gulesserian, Maria Christina Malinao, Sathish Kumar-Ganesan, James Song, Mi Sook Chang, Melissa M Williams, Zhilan Zeng, Michael Mattie, Brian A Mendelsohn, David R Stover, Fernando Doñate
Neutropenia is a common adverse event in cancer patients treated with antibody-drug conjugates (ADCs) and we aimed to elucidate the potential mechanism of this toxicity. To investigate if ADCs affect neutrophil production from bone marrow, an in vitro assay was developed in which hematopoietic stem cells (HSCs) were differentiated to neutrophils. Several antibodies against targets absent in HSCs and neutrophils were conjugated to MMAE via a cleavable valine-citrulline linker (vcMMAE-ADCs) or MMAF via a non-cleavable maleimidocaproyl linker (mcMMAF-ADCs), and their cytotoxicity was tested in the neutrophil differentiation assay...
May 18, 2017: Molecular Cancer Therapeutics
https://www.readbyqxmd.com/read/28522322/imaging-macropinosomes-during-shigella-infections
#17
REVIEW
Noelia Lopez-Montero, Yuen-Yan Chang, Anna Sartori-Rupp, Sonja Kühn, Jost Enninga
Macropinocytosis is the uptake of extracellular fluid within vesicles of varying size that takes place during numerous cellular processes in a large variety of cells. A growing number of pathogens, including viruses, parasites, and bacteria are known to induce macropinocytosis during their entry into targeted host cells. We have recently discovered that the human enteroinvasive, bacterial pathogen Shigella causes in situ macropinosome formation during its entry into epithelial cells. These infection-associated macropinosomes are not generated to ingest the bacteria, but are instead involved in Shigella's intracellular niche formation...
May 15, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28516118/quantitative-measurements-of-hiv-1-and-dextran-capture-by-human-monocyte-derived-dendritic-cells-mddcs
#18
Mickaël M Ménager, Dan R Littman
The aim of this protocol is to describe how to measure and quantify the amount of HIV-1 particles and dextran molecules internalized in human monocyte derived dendritic cells (MDDCs), using three different techniques: flow cytometry, quantitative PCR and confocal microscopy. BACKGROUND: This protocol was developed in order to assess the changes of HIV-1 internalization upon disruption of actin nucleation in human monocyte derived dendritic cells. Following a shRNA screen to identify genes important for HIV-1 transfer from dendritic cells to T cells, we observed that a disruption of actin nucleation leads to a switch from actin rich dendrites to blebs, due to an excess of actomyosin contraction...
November 20, 2016: Bio-protocol
https://www.readbyqxmd.com/read/28515429/endocytic-uptake-of-monomeric-amyloid-%C3%AE-peptides-is-clathrin-and-dynamin-independent-and-results-in-selective-accumulation-of-a%C3%AE-1-42-compared-to-a%C3%AE-1-40
#19
Emelie Wesén, Gavin D M Jeffries, Maria Matson Dzebo, Elin K Esbjörner
Intraneuronal accumulation of amyloid-β (Aβ) peptides represent an early pathological feature in Alzheimer's disease. We have therefore utilized flow cytometry and confocal microscopy in combination with endocytosis inhibition to explore the internalisation efficiency and uptake mechanisms of Aβ(1-40) and Aβ(1-42) monomers in cultured SH-SY5Y cells. We find that both variants are constitutively internalised via endocytosis and that their uptake is proportional to cellular endocytic rate. Moreover, SH-SY5Y cells internalise consistently twice the amount of Aβ(1-42) compared to Aβ(1-40); an imaging-based quantification showed that cells treated with 1 µM peptide for 8 h contained 800,000 peptides of Aβ(1-42) and 400,000 of Aβ(1-40)...
May 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28512335/arginine-rich-cell-penetrating-peptide-modified-extracellular-vesicles-for-active-macropinocytosis-induction-and-efficient-intracellular-delivery
#20
Ikuhiko Nakase, Kosuke Noguchi, Ayako Aoki, Tomoka Takatani-Nakase, Ikuo Fujii, Shiroh Futaki
Extracellular vesicles (EVs) including exosomes have been shown to play crucial roles in cell-to-cell communication because of their ability to carry biofunctional molecules (e.g., microRNAs and enzymes). EVs also have pharmaceutical advantages and are highly anticipated to be a next-generation intracellular delivery tool. Here, we demonstrate an experimental technique that uses arginine-rich cell-penetrating peptide (CPP)-modified EVs to induce active macropinocytosis for effective cellular EV uptake. Modification of arginine-rich CPPs on the EV membrane resulted in the activation of the macropinocytosis pathway, and the number of arginine residues in the peptide sequences affected the cellular EV uptake efficiency...
May 16, 2017: Scientific Reports
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