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Chen R, Wang L, Ding G, Han G, Qiu K, Sun Y, Diao J. Constant Conversion Rate of Endolysosomes Revealed by a pH-Sensitive Fluorescent Probe. ACS Sens 2023; 8:2068-2078. [PMID: 37141429 DOI: 10.1021/acssensors.3c00340] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Endolysosome dynamics plays an important role in autophagosome biogenesis. Hence, imaging the subcellular dynamics of endolysosomes using high-resolution fluorescent imaging techniques would deepen our understanding of autophagy and benefit the development of pharmaceuticals against endosome-related diseases. Taking advantage of the intramolecular charge-transfer mechanism, herein we report a cationic quinolinium-based fluorescent probe (PyQPMe) that exhibits excellent pH-sensitive fluorescence in endolysosomes at different stages of interest. A systematic photophysical and computational study on PyQPMe was carried out to rationalize its highly pH-dependent absorption and emission spectra. The large Stokes shift and strong fluorescence intensity of PyQPMe can effectively reduce the background noise caused by excitation light and microenvironments and provide a high signal-to-noise ratio for high-resolution imaging of endolysosomes. By applying PyQPMe as a small molecular probe in live cells, we were able to reveal a constant conversion rate from early endosomes to late endosomes/lysosomes during autophagy at the submicron level.
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Affiliation(s)
- Rui Chen
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Lei Wang
- Department of Cancer Biology, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, United States
| | - Guodong Ding
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Guanqun Han
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Kangqiang Qiu
- Department of Cancer Biology, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, United States
| | - Yujie Sun
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Jiajie Diao
- Department of Cancer Biology, College of Medicine, University of Cincinnati, Cincinnati, Ohio 45267, United States
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2
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p38 Mitogen-Activated Protein Kinase Signaling Enhances Reovirus Replication by Facilitating Efficient Virus Entry, Capsid Uncoating, and Postuncoating Steps. J Virol 2023; 97:e0000923. [PMID: 36744961 PMCID: PMC9972948 DOI: 10.1128/jvi.00009-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Mammalian orthoreovirus serotype 3 Dearing is an oncolytic virus currently undergoing multiple clinical trials as a potential cancer therapy. Previous clinical trials have emphasized the importance of prescreening patients for prognostic markers to improve therapeutic success. However, only generic cancer markers such as epidermal growth factor receptor (EGFR), Hras, Kras, Nras, Braf, and p53 are currently utilized, with limited benefit in predicting therapeutic efficacy. This study aimed to investigate the role of p38 mitogen-activated protein kinase (MAPK) signaling during reovirus infection. Using a panel of specific p38 MAPK inhibitors and an inactive inhibitor analogue, p38 MAPK signaling was found to be essential for establishment of reovirus infection by enhancing reovirus endocytosis, facilitating efficient reovirus uncoating at the endo-lysosomal stage, and augmenting postuncoating replication steps. Using a broad panel of human breast cancer cell lines, susceptibility to reovirus infection corresponded with virus binding and uncoating efficiency, which strongly correlated with status of the p38β isoform. Together, results suggest p38β isoform as a potential prognostic marker for early stages of reovirus infection that are crucial to successful reovirus infection. IMPORTANCE The use of Pelareorep (mammalian orthoreovirus) as a therapy for metastatic breast cancer has shown promising results in recent clinical trials. However, the selection of prognostic markers to stratify patients has had limited success due to the fact that these markers are upstream receptors and signaling pathways that are present in a high percentage of cancers. This study demonstrates that the mechanism of action of p38 MAPK signaling plays a key role in establishment of reovirus infection at both early entry and late replication steps. Using a panel of breast cancer cell lines, we found that the expression levels of the MAPK11 (p38β) isoform are a strong determinant of reovirus uncoating and infection establishment. Our findings suggest that selecting prognostic markers that target key steps in reovirus replication may improve patient stratification during oncolytic reovirus therapy.
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3
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Qiu K, Seino R, Han G, Ishiyama M, Ueno Y, Tian Z, Sun Y, Diao J. De Novo Design of A Membrane-Anchored Probe for Multidimensional Quantification of Endocytic Dynamics. Adv Healthc Mater 2022; 11:e2102185. [PMID: 35032365 PMCID: PMC9035050 DOI: 10.1002/adhm.202102185] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/10/2022] [Indexed: 11/10/2022]
Abstract
As a process of cellular uptake, endocytosis, with gradient acidity in different endocytic vesicles, is vital for the homeostasis of intracellular nutrients and other functions. To study the dynamics of endocytic pathway, a membrane-anchored pH probe, ECGreen, is synthesized to visualize endocytic vesicles under structured illumination microscopy (SIM), a super-resolution technology. Being sensitive to acidity with increasing fluorescence at low pH, ECGreen can differentiate early and late endosomes as well as endolysosomes. Meanwhile, membrane anchoring not only improves the durability of ECGreen, but also provides an excellent anti-photobleaching property for long-time imaging with SIM. Moreover, by taking these advantages of ECGreen, a multidimensional analysis model containing spatial, temporal, and pH information is successfully developed for elucidating the dynamics of endocytic vesicles and their interactions with mitochondria during autophagy, and reveals a fast conversion of endosomes near the plasma membrane.
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Affiliation(s)
- Kangqiang Qiu
- Department of Cancer Biology College of Medicine University of Cincinnati Cincinnati OH 45267 USA
| | - Ryo Seino
- Dojindo Laboratories Kumamoto 861‐2202 Japan
| | - Guanqun Han
- Department of Chemistry University of Cincinnati Cincinnati OH 45221 USA
| | | | | | - Zhiqi Tian
- Department of Cancer Biology College of Medicine University of Cincinnati Cincinnati OH 45267 USA
| | - Yujie Sun
- Department of Chemistry University of Cincinnati Cincinnati OH 45221 USA
| | - Jiajie Diao
- Department of Cancer Biology College of Medicine University of Cincinnati Cincinnati OH 45267 USA
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4
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Garcia Romeu H, Deville S, Salvati A. Time- and Space-Resolved Flow-Cytometry of Cell Organelles to Quantify Nanoparticle Uptake and Intracellular Trafficking by Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2100887. [PMID: 34272923 DOI: 10.1002/smll.202100887] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 06/15/2021] [Indexed: 05/20/2023]
Abstract
The design of targeted nanomedicines requires intracellular space- and time-resolved data of nanoparticle distribution following uptake. Current methods to study intracellular trafficking, such as dynamic colocalization by fluorescence microscopy in live cells, are usually low throughput and require extensive analysis of large datasets to quantify colocalization in several individual cells. Here a method based on flow cytometry to easily detect and characterize the organelles in which nanoparticles are internalized and trafficked over time is proposed. Conventional cell fractionation methods are combined with immunostaining and high-sensitivity organelle flow cytometry to get space-resolved data of nanoparticle intracellular distribution. By extracting the organelles at different times, time-resolved data of nanoparticle intracellular trafficking are obtained. The method is validated by determining how nanoparticle size affects the kinetics of arrival to the lysosomes. The results demonstrate that this method allows high-throughput analysis of nanoparticle uptake and intracellular trafficking by cells, therefore it can be used to determine how nanoparticle design affects their intracellular behavior.
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Affiliation(s)
- Hector Garcia Romeu
- Department of Nanomedicine & Drug Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, Groningen, 9713AV, The Netherlands
| | - Sarah Deville
- Department of Nanomedicine & Drug Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, Groningen, 9713AV, The Netherlands
- Health Unit, Flemish Institute for Technological Research, Boeretang 200, Mol, 2400, Belgium
| | - Anna Salvati
- Department of Nanomedicine & Drug Targeting, Groningen Research Institute of Pharmacy, University of Groningen, A. Deusinglaan 1, Groningen, 9713AV, The Netherlands
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5
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Zila V, Margiotta E, Turoňová B, Müller TG, Zimmerli CE, Mattei S, Allegretti M, Börner K, Rada J, Müller B, Lusic M, Kräusslich HG, Beck M. Cone-shaped HIV-1 capsids are transported through intact nuclear pores. Cell 2021; 184:1032-1046.e18. [PMID: 33571428 PMCID: PMC7895898 DOI: 10.1016/j.cell.2021.01.025] [Citation(s) in RCA: 166] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/20/2020] [Accepted: 01/19/2021] [Indexed: 12/14/2022]
Abstract
Human immunodeficiency virus (HIV-1) remains a major health threat. Viral capsid uncoating and nuclear import of the viral genome are critical for productive infection. The size of the HIV-1 capsid is generally believed to exceed the diameter of the nuclear pore complex (NPC), indicating that capsid uncoating has to occur prior to nuclear import. Here, we combined correlative light and electron microscopy with subtomogram averaging to capture the structural status of reverse transcription-competent HIV-1 complexes in infected T cells. We demonstrated that the diameter of the NPC in cellulo is sufficient for the import of apparently intact, cone-shaped capsids. Subsequent to nuclear import, we detected disrupted and empty capsid fragments, indicating that uncoating of the replication complex occurs by breaking the capsid open, and not by disassembly into individual subunits. Our data directly visualize a key step in HIV-1 replication and enhance our mechanistic understanding of the viral life cycle.
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Affiliation(s)
- Vojtech Zila
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Erica Margiotta
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany; Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Beata Turoňová
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Thorsten G Müller
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Christian E Zimmerli
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Simone Mattei
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany; Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8092 Zurich, Switzerland; European Molecular Biology Laboratory, Imaging Center, 69117 Heidelberg, Germany
| | - Matteo Allegretti
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Kathleen Börner
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany; German Center for Infection Research, partner site Heidelberg, 69120 Heidelberg, Germany
| | - Jona Rada
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Barbara Müller
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Marina Lusic
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany; German Center for Infection Research, partner site Heidelberg, 69120 Heidelberg, Germany
| | - Hans-Georg Kräusslich
- Department of Infectious Diseases, Virology, University of Heidelberg, 69120 Heidelberg, Germany; German Center for Infection Research, partner site Heidelberg, 69120 Heidelberg, Germany.
| | - Martin Beck
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany; Max Planck Institute of Biophysics, Department of Molecular Sociology, 60438 Frankfurt, Germany.
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6
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Koike K, Bando K, Ando J, Yamakoshi H, Terayama N, Dodo K, Smith NI, Sodeoka M, Fujita K. Quantitative Drug Dynamics Visualized by Alkyne-Tagged Plasmonic-Enhanced Raman Microscopy. ACS NANO 2020; 14:15032-15041. [PMID: 33079538 DOI: 10.1021/acsnano.0c05010] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Visualizing live-cell uptake of small-molecule drugs is paramount for drug development and pharmaceutical sciences. Bioorthogonal imaging with click chemistry has made significant contributions to the field, visualizing small molecules in cells. Furthermore, recent developments in Raman microscopy, including stimulated Raman scattering (SRS) microscopy, have realized direct visualization of alkyne-tagged small-molecule drugs in live cells. However, Raman and SRS microscopy still suffer from limited detection sensitivity with low concentration molecules for observing temporal dynamics of drug uptake. Here, we demonstrate the combination of alkyne-tag and surface-enhanced Raman scattering (SERS) microscopy for the real-time monitoring of drug uptake in live cells. Gold nanoparticles are introduced into lysosomes of live cells by endocytosis and work as SERS probes. Raman signals of alkynes can be boosted by enhanced electric fields generated by plasmon resonance of gold nanoparticles when alkyne-tagged small molecules are colocalized with the nanoparticles. With time-lapse 3D SERS imaging, this technique allows us to investigate drug uptake by live cells with different chemical and physical conditions. We also perform quantitative evaluation of the uptake speed at the single-cell level using digital SERS counting under different quantities of drug molecules and temperature conditions. Our results illustrate that alkyne-tag SERS microscopy has a potential to be an alternative bioorthogonal imaging technique to investigate temporal dynamics of small-molecule uptake of live cells for pharmaceutical research.
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Affiliation(s)
- Kota Koike
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- AIST-Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kazuki Bando
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Jun Ando
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hiroyuki Yamakoshi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603, Japan
| | - Naoki Terayama
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kosuke Dodo
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Nicholas Isaac Smith
- Immunology Frontier Research Center, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mikiko Sodeoka
- Synthetic Organic Chemistry Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Katsumasa Fujita
- Department of Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- AIST-Osaka University Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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7
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Direct monitoring of live human pluripotent stem cells by a highly selective pluripotency sensor. Bioorg Med Chem Lett 2020; 30:127347. [PMID: 32631546 DOI: 10.1016/j.bmcl.2020.127347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/08/2020] [Accepted: 06/09/2020] [Indexed: 11/24/2022]
Abstract
Human pluripotent stem cells (hPSCs) are a useful cell source for regenerative medicine. Despite having a potential of hPSCs for cell-based therapy, there is a need for a selective human pluripotency sensor for monitoring of live hPSCs. Here, we report the discovery of a novel pluripotency sensor (SHI5) from BODIPY-based library by high-throughput cell-based screening and describe the use of SHI5 to identify and isolate human embryonic stem cells and human induced pluripotent stem cells. We demonstrate that SHI5-based assay can be applied to live cells that gain pluripotency in the reprogramming process without any effect on their viability. We also show that SHI5 is internalized through a clathrin-mediated endocytosis pathway. These findings suggest that SHI5 can be an attractive sensor for pluripotency cells during reprogramming. Taken together, SHI5-based screening for hPSCs opens probably unlimited possibilities of detection probe for hPSC therapy via assures their safety issue.
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8
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Jonker CTH, Deo C, Zager PJ, Tkachuk AN, Weinstein AM, Rodriguez-Boulan E, Lavis LD, Schreiner R. Accurate measurement of fast endocytic recycling kinetics in real time. J Cell Sci 2020; 133:jcs.231225. [PMID: 31843759 DOI: 10.1242/jcs.231225] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 12/09/2019] [Indexed: 01/01/2023] Open
Abstract
The fast turnover of membrane components through endocytosis and recycling allows precise control of the composition of the plasma membrane. Endocytic recycling can be rapid, with some molecules returning to the plasma membrane with a half time <5 min. Existing methods to study these trafficking pathways utilize chemical, radioactive or fluorescent labeling of cell surface receptors in pulse-chase experiments, which require tedious washing steps and manual collection of samples. Here, we introduce a live-cell endocytic recycling assay based on a newly designed cell-impermeable fluorogenic ligand for HaloTag, Janelia Fluor 635i (JF635i, where i indicates impermeant), which allows real-time detection of membrane receptor recycling at steady state. We used this method to study the effect of iron depletion on transferrin receptor (TfR) recycling using the chelator desferrioxamine. We found that this perturbation significantly increases the TfR recycling rate. The high temporal resolution and simplicity of this assay provides a clear advantage over extant methods and makes it ideal for large scale cellular imaging studies. This assay can be adapted to examine other cellular kinetic parameters such as protein turnover and biosynthetic trafficking.
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Affiliation(s)
- Caspar T H Jonker
- Weill Cornell Medicine, Department of Ophthalmology, Margaret Dyson Vision Research Institute, New York, NY, 10065, USA
| | - Claire Deo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - Patrick J Zager
- Weill Cornell Medicine, Department of Ophthalmology, Margaret Dyson Vision Research Institute, New York, NY, 10065, USA
| | - Ariana N Tkachuk
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Department of Medicine, Weill Cornell Medicine, New York, New York 10065, USA
| | - Enrique Rodriguez-Boulan
- Weill Cornell Medicine, Department of Ophthalmology, Margaret Dyson Vision Research Institute, New York, NY, 10065, USA
| | - Luke D Lavis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia 20147, United States
| | - Ryan Schreiner
- Weill Cornell Medicine, Department of Ophthalmology, Margaret Dyson Vision Research Institute, New York, NY, 10065, USA
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9
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Abstract
The HIV-1 capsid performs essential functions during early viral replication and is an interesting target for novel antivirals. Thus, understanding molecular and structural details of capsid function will be important for elucidating early HIV-1 (and retroviral in general) replication in relevant target cells and may also aid antiviral development. Here, we show that HIV-1 capsids stay largely intact during transport to the nucleus of infected T cells but appear to uncoat upon entry into the nucleoplasm. These results support the hypothesis that capsids protect the HIV-1 genome from cytoplasmic defense mechanisms and target the genome toward the nucleus. A protective role of the capsid could be a paradigm that also applies to other viruses. Our findings raise the question of how reverse transcription of the HIV-1 genome is accomplished in the context of the capsid structure and whether the process is completed before the capsid is uncoated at the nuclear pore. HIV-1 infects host cells by fusion at the plasma membrane, leading to cytoplasmic entry of the viral capsid encasing the genome and replication machinery. The capsid eventually needs to disassemble, but time and location of uncoating are not fully characterized and may vary depending on the host cell. To study the fate of the capsid by fluorescence and superresolution (STED) microscopy, we established an experimental system that allows discrimination of subviral structures in the cytosol from intact virions at the plasma membrane or in endosomes without genetic modification of the virus. Quantitative microscopy of infected SupT1-R5 cells revealed that the CA signal on cytosolic HIV-1 complexes corresponded to ∼50% of that found in virions at the cell surface, in agreement with dissociation of nonassembled CA molecules from entering capsids after membrane fusion. The relative amount of CA in postfusion complexes remained stable until they reached the nuclear pore complex, while subviral structures in the nucleus of infected cells lacked detectable CA. An HIV-1 variant defective in binding of the host protein cleavage and polyadenylation specificity factor 6 (CPSF6) exhibited accumulation of CA-positive subviral complexes close to the nuclear envelope without loss of infectivity; STED microscopy revealed direct association of these complexes with nuclear pores. These results support previous observations indicating capsid uncoating at the nuclear pore in infected T-cell lines. They suggest that largely intact HIV-1 capsids dock at the nuclear pore in infected SupT1-R5 cells, with CPSF6 being a facilitator of nucleoplasmic entry in this cell type, as has been observed for infected macrophages.
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Intracellular Trafficking and Translocation of Pertussis Toxin. Toxins (Basel) 2019; 11:toxins11080437. [PMID: 31349590 PMCID: PMC6723225 DOI: 10.3390/toxins11080437] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 07/24/2019] [Indexed: 12/25/2022] Open
Abstract
Pertussis toxin (PT) is a multimeric complex of six proteins. The PTS1 subunit is an ADP-ribosyltransferase that inactivates the alpha subunit of heterotrimeric Gi/o proteins. The remaining PT subunits form a pentamer that positions PTS1 in and above the central cavity of the triangular structure. Adhesion of this pentamer to glycoprotein or glycolipid conjugates on the surface of a target cell leads to endocytosis of the PT holotoxin. Vesicle carriers then deliver the holotoxin to the endoplasmic reticulum (ER) where PTS1 dissociates from the rest of the toxin, unfolds, and exploits the ER-associated degradation pathway for export to the cytosol. Refolding of the cytosolic toxin allows it to regain an active conformation for the disruption of cAMP-dependent signaling events. This review will consider the intracellular trafficking of PT and the order-disorder-order transitions of PTS1 that are essential for its cellular activity.
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11
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Hypoxia/hypercapnia prevents iron-dependent cold injuries in cord blood stem and progenitor cells. Cytotherapy 2019; 21:460-467. [PMID: 30878383 DOI: 10.1016/j.jcyt.2019.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 02/01/2019] [Accepted: 02/19/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cold-induced cell injuries are associated with an increase in the cellular labile iron pool (LIP) followed by lipid peroxidation and alteration of mitochondrial function, which lead to cell death. Recently, we showed that incubation in a hypoxic/hypercapnic (HH) gas mixture improved the survival of a population of cord blood hematopoietic progenitors and CD34+ hematopoietic progenitor and stem cells in severe hypothermia. To explain the underlying mechanism, here we test if this HH-induced cytoprotection in cold conditions is associated with the level of LIP and lysosome stability. METHODS Cord blood CD34+ cells were incubated in air (20% O2/0.05% CO2) or in the hypoxic (5% O2)/hypercapnic (9% CO2) atmosphere for 7days at 4°C and analyzed. RESULTS Incubation in HH condition maintained the day 0 (D-0) level of LIP detected using a bleomycin-dependent method. This was associated with preservation of lysosome integrity and a higher cell survival. Conversely, in the air condition LIP was significantly increased. Also, the presence of a moderate concentration of iron chelator deferoximine improves the conservation of total CD34+ cells and committed progenitors in air condition. Pre-treatment of CD34+ cells with the lysomotropic agent imidazole induces significant decrease in the lysosomal stability and in all conditions. This is associated with an important decrease of survival of conserved cells and an increase in the cellular LIP level. DISCUSSION Our study showed that HH gas mixture cytoprotection during hypothermia maintains lysosome stability, which enables preservation of the cellular chelatable iron in the physiological ranges. These findings suggest a way to optimize cell conservation without freezing.
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12
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Crawford T, Fletcher N, Veitch M, Gonzalez Cruz JL, Pett N, Brereton I, Wells JW, Mobli M, Tesiram Y. Bacillus anthracis Protective Antigen Shows High Specificity for a UV Induced Mouse Model of Cutaneous Squamous Cell Carcinoma. Front Med (Lausanne) 2019; 6:22. [PMID: 30809524 PMCID: PMC6379334 DOI: 10.3389/fmed.2019.00022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 01/24/2019] [Indexed: 11/13/2022] Open
Abstract
Squamous cell carcinoma (SCC) accounts for the majority of non-melanoma skin cancer related deaths, particularly in immunosuppressed persons. Identification of biomarkers that could be used to identify or treat SCC would be of significant benefit. The anthrax toxin receptors, Tumor Endothelial Marker 8 (TEM8) and Capillary Morphogenesis Gene 2 (CMG2), are endothelial receptors involved in extracellular matrix homeostasis and angiogenesis that are selectively upregulated on numerous tumors. One method of targeting these receptors is Protective Antigen (PA), a protein produced by B. anthracis that mediates binding and translocation of anthrax toxins into cells. PA targeted toxins have been demonstrated to selectively inhibit tumor growth and angiogenesis, but tumor selectivity of PA is currently unknown. In this work fluorescently labeled PA was shown to maintain receptor dependent binding and internalization in vitro. Utilizing a human papillomavirus transgenic mouse model that develops cutaneous SCC in response to ultraviolet irradiation we identified tumor uptake of PA in vivo. The intravenously administered PA resulted in tumor specific localization, with exclusive tumor detection 24 h post injection. Ex vivo analysis identified significantly higher fluorescence in the tumor compared to adjacent healthy tissue and major clearance organs, demonstrating low non-specific uptake and rapid clearance. While both TEM8 and CMG2 were observed to be overexpressed in SCC tumor sections compared to control skin, the intravenously administered PA was primarily co-localized with TEM8. These results suggest that PA could be systemically administered for rapid identification of cutaneous SCC, with potential for further therapeutic development.
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Affiliation(s)
- Theo Crawford
- Centre for Advanced Imaging (CAI), The University of Queensland, Brisbane, QLD, Australia
| | - Nicholas Fletcher
- Centre for Advanced Imaging (CAI), The University of Queensland, Brisbane, QLD, Australia.,Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia.,Australian Research Council (ARC) Centre of Excellence in Convergent BioNano Science and Technology, Queensland Node, The University of Queensland, Brisbane, QLD, Australia
| | - Margaret Veitch
- Faculty of Medicine, Translational Research Institute, University of Queensland Diamantina Institute, Brisbane, QLD, Australia
| | - Jazmina L Gonzalez Cruz
- Faculty of Medicine, Translational Research Institute, University of Queensland Diamantina Institute, Brisbane, QLD, Australia
| | - Nicola Pett
- Faculty of Medicine, Translational Research Institute, University of Queensland Diamantina Institute, Brisbane, QLD, Australia
| | - Ian Brereton
- Centre for Advanced Imaging (CAI), The University of Queensland, Brisbane, QLD, Australia
| | - James W Wells
- Faculty of Medicine, Translational Research Institute, University of Queensland Diamantina Institute, Brisbane, QLD, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging (CAI), The University of Queensland, Brisbane, QLD, Australia
| | - Yasvir Tesiram
- Centre for Advanced Imaging (CAI), The University of Queensland, Brisbane, QLD, Australia
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13
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Alcantara CDL, de Souza W, da Cunha E Silva NL. Tridimensional Electron Microscopy Analysis of the Early Endosomes and Endocytic Traffic in Trypanosoma cruzi Epimastigotes. Protist 2018; 169:887-910. [PMID: 30447618 DOI: 10.1016/j.protis.2018.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 08/25/2018] [Accepted: 09/24/2018] [Indexed: 02/04/2023]
Abstract
Trypanosoma cruzi epimastigotes internalize macromolecules avidly by endocytosis. Previously, we identified a tubule-vesicular network likely to correspond to the early-endosomes. However, a detailed ultrastructural characterization of these endosomes was missing. Here, we combined endocytosis assays with ultrastructural data from high-resolution electron microscopy to produce a 3D analysis of epimastigote endosomes and their interactions with endocytic organelles. We showed that endocytic cargo was found in carrier vesicles budding from the cytopharynx. These vesicles appeared to fuse with a tubule-vesicular network of early endosomes identified by ultrastructural features including the presence of intermembrane invaginations and coated membrane sections. Within the posterior region of the cell, endosomes localized preferentially on the side nearest to the cytopharynx microtubules. At 4°C, cargo accumulated at a shortened cytopharynx, and subsequent temperature shift to 12°C led to slow cargo delivery to endosomes and, later, to reservosomes. Bridges between reservosomes and endosomes resemble heterotypic fusion. Reservosomes are excluded from the posterior end of the cell, with no preferential cargo delivery to reservosomes closer to the nucleus. Our 3D analysis indicates that epimastigotes accomplish high-speed endocytic traffic by cargo transfer to a bona fide early-endosome and then directly from endosomes to reservosomes, via multiple and simultaneous heterotypic fusion events.
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Affiliation(s)
- Carolina de Lima Alcantara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; Núcleo de Biologia Estrutural e Bioimagens (CENABIO) - Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro 21941-902, RJ, Brazil.
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; Núcleo de Biologia Estrutural e Bioimagens (CENABIO) - Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro 21941-902, RJ, Brazil
| | - Narcisa L da Cunha E Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, RJ, Brazil; Núcleo de Biologia Estrutural e Bioimagens (CENABIO) - Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens (INBEB), Rio de Janeiro 21941-902, RJ, Brazil
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14
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Sunoqrot S, Al-Shalabi E, Messersmith PB. Facile synthesis and surface modification of bioinspired nanoparticles from quercetin for drug delivery. Biomater Sci 2018; 6:2656-2666. [PMID: 30140818 PMCID: PMC6168948 DOI: 10.1039/c8bm00587g] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Nanoparticle-mediated drug delivery has demonstrated great potential to treat various diseases especially cancer. However, there is an unmet need for the scalable synthesis of multifunctional nanoparticles to meet the complex challenges of drug delivery. Here we show that we can synthesize nanoparticles from the polyphenol quercetin, which can be conveniently functionalized with ligands and drug molecules by simple mixing under ambient conditions. Nanoparticles (∼30-40 nm in diameter) were formed by oxidative self-polymerization of quercetin in alkaline buffer (pH 9). The reactivity of oxidized polyphenols was exploited to immobilize amine-terminated methoxy poly(ethylene glycol) on the nanoparticles' surface for steric stability, followed by loading with doxorubicin as a model drug. Surface modification of the nanoparticles was confirmed by X-ray Photoelectron Spectroscopy. An antioxidant assay showed that the nanoparticles retained some antioxidant activity. The nanoparticles were readily internalized by KB cells via an endo-lysosomal pathway. Doxorubicin-loaded nanoparticles showed a drug loading of 35.6 ± 4.9% w/w with a loading efficiency of 88.9 ± 12.4%, sustained drug release, and potent cytotoxicity in vitro. Our findings demonstrate a promising new application for naturally occurring polyphenols as a renewable source of drug delivery nanocarriers that can be synthesized at low cost with minimal equipment.
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Affiliation(s)
- Suhair Sunoqrot
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman 11733, Jordan.
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15
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Zobel M, Disanza A, Senic-Matuglia F, Franco M, Colaluca IN, Confalonieri S, Bisi S, Barbieri E, Caldieri G, Sigismund S, Pece S, Chavrier P, Di Fiore PP, Scita G. A NUMB-EFA6B-ARF6 recycling route controls apically restricted cell protrusions and mesenchymal motility. J Cell Biol 2018; 217:3161-3182. [PMID: 30061108 PMCID: PMC6123001 DOI: 10.1083/jcb.201802023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/17/2018] [Accepted: 06/05/2018] [Indexed: 12/13/2022] Open
Abstract
The endocytic protein NUMB has been implicated in the control of various polarized cellular processes, including the acquisition of mesenchymal migratory traits through molecular mechanisms that have only been partially defined. Here, we report that NUMB is a negative regulator of a specialized set of understudied, apically restricted, actin-based protrusions, the circular dorsal ruffles (CDRs), induced by either PDGF or HGF stimulation. Through its PTB domain, NUMB binds directly to an N-terminal NPLF motif of the ARF6 guanine nucleotide exchange factor, EFA6B, and promotes its exchange activity in vitro. In cells, a NUMB-EFA6B-ARF6 axis regulates the recycling of the actin regulatory cargo RAC1 and is critical for the formation of CDRs that mark the acquisition of a mesenchymal mode of motility. Consistently, loss of NUMB promotes HGF-induced cell migration and invasion. Thus, NUMB negatively controls membrane protrusions and the acquisition of mesenchymal migratory traits by modulating EFA6B-ARF6 activity.
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Affiliation(s)
- Martina Zobel
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Andrea Disanza
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Michel Franco
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | | | | | - Sara Bisi
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Elisa Barbieri
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Giusi Caldieri
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Sara Sigismund
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Salvatore Pece
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Philippe Chavrier
- Institut Curie, PSL Research University, Paris, France
- Centre National de la Recherche Scientifique UMR 144, Membrane and Cytoskeleton Dynamics Team, Paris, France
| | - Pier Paolo Di Fiore
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Giorgio Scita
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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16
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Zhang X, Ren J, Wang J, Li S, Zou Q, Gao N. Receptor-mediated endocytosis generates nanomechanical force reflective of ligand identity and cellular property. J Cell Physiol 2018; 233:5908-5919. [PMID: 29243828 DOI: 10.1002/jcp.26400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/12/2017] [Indexed: 01/07/2023]
Abstract
Whether environmental (thermal, chemical, and nutrient) signals generate quantifiable, nanoscale, mechanophysical changes in the cellular plasma membrane has not been well elucidated. Assessment of such mechanophysical properties of plasma membrane may shed lights on fundamental cellular process. Atomic force microscopic (AFM) measurement of the mechanical properties of live cells was hampered by the difficulty in accounting for the effects of the cantilever motion and the associated hydrodynamic force on the mechanical measurement. These challenges have been addressed in our recently developed control-based AFM nanomechanical measurement protocol, which enables a fast, noninvasive, broadband measurement of the real-time changes in plasma membrane elasticity in live cells. Here we show using this newly developed AFM platform that the plasma membrane of live mammalian cells exhibits a constant and quantifiable nanomechanical property, the membrane elasticity. This mechanical property sensitively changes in response to environmental factors, such as the thermal, chemical, and growth factor stimuli. We demonstrate that different chemical inhibitors of endocytosis elicit distinct changes in plasma membrane elastic modulus reflecting their specific molecular actions on the lipid configuration or the endocytic machinery. Interestingly, two different growth factors, EGF and Wnt3a, elicited distinct elastic force profiles revealed by AFM at the plasma membrane during receptor-mediated endocytosis. By applying this platform to genetically modified cells, we uncovered a previously unknown contribution of Cdc42, a key component of the cellular trafficking network, to EGF-stimulated endocytosis at plasma membrane. Together, this nanomechanical AFM study establishes an important foundation that is expandable and adaptable for investigation of cellular membrane evolution in response to various key extracellular signals.
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Affiliation(s)
- Xiao Zhang
- Department of Biological Sciences, Rutgers University, Newark, New Jersey
| | - Juan Ren
- Department of Mechanical Engineering, Iowa State University, Ames, Iowa
| | - Jingren Wang
- Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, New Jersey
| | - Shixie Li
- Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, New Jersey
| | - Qingze Zou
- Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, New Jersey
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, New Jersey
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17
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López-Ortega O, Santos-Argumedo L. Myosin 1g Contributes to CD44 Adhesion Protein and Lipid Rafts Recycling and Controls CD44 Capping and Cell Migration in B Lymphocytes. Front Immunol 2017; 8:1731. [PMID: 29321775 PMCID: PMC5732150 DOI: 10.3389/fimmu.2017.01731] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/23/2017] [Indexed: 12/30/2022] Open
Abstract
Cell migration and adhesion are critical for immune system function and involve many proteins, which must be continuously transported and recycled in the cell. Recycling of adhesion molecules requires the participation of several proteins, including actin, tubulin, and GTPases, and of membrane components such as sphingolipids and cholesterol. However, roles of actin motor proteins in adhesion molecule recycling are poorly understood. In this study, we identified myosin 1g as one of the important motor proteins that drives recycling of the adhesion protein CD44 in B lymphocytes. We demonstrate that the lack of Myo1g decreases the cell-surface levels of CD44 and of the lipid raft surrogate GM1. In cells depleted of Myo1g, the recycling of CD44 was delayed, the delay seems to be caused at the level of formation of recycling complex and entry into recycling endosomes. Moreover, a defective lipid raft recycling in Myo1g-deficient cells had an impact both on the capping of CD44 and on cell migration. Both processes required the transportation of lipid rafts to the cell surface to deliver signaling components. Furthermore, the extramembrane was essential for cell expansion and remodeling of the plasma membrane topology. Therefore, Myo1g is important during the recycling of lipid rafts to the membrane and to the accompanied proteins that regulate plasma membrane plasticity. Thus, Myosin 1g contributes to cell adhesion and cell migration through CD44 recycling in B lymphocytes.
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Affiliation(s)
- Orestes López-Ortega
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
| | - Leopoldo Santos-Argumedo
- Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
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18
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Roti G, Qi J, Kitara S, Sanchez-Martin M, Saur Conway A, Varca AC, Su A, Wu L, Kung AL, Ferrando AA, Bradner JE, Stegmaier K. Leukemia-specific delivery of mutant NOTCH1 targeted therapy. J Exp Med 2017; 215:197-216. [PMID: 29158376 PMCID: PMC5748843 DOI: 10.1084/jem.20151778] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 08/17/2017] [Accepted: 10/09/2017] [Indexed: 12/15/2022] Open
Abstract
NOTCH1 is an attractive cancer target, particularly in T cell acute lymphoblastic leukemia (T-ALL), with activating mutations in this gene identified in more than 50% of cases. In this study, Roti et al. describe the synthesis, characterization, and validation of JQ-FT, a first-in-class NOTCH1 inhibitor that has dual selectivity for leukemia over normal cells and NOTCH1 mutants over wild-type receptors. On-target drug delivery remains a challenge in cancer precision medicine; it is difficult to deliver a targeted therapy to cancer cells without incurring toxicity to normal tissues. The SERCA (sarco-endoplasmic reticulum Ca2+ ATPase) inhibitor thapsigargin inhibits mutant NOTCH1 receptors compared with wild type in T cell acute lymphoblastic leukemia (T-ALL), but its administration is predicted to be toxic in humans. Leveraging the addiction of ALL to folic acid, we conjugated folate to an alcohol derivative of thapsigargin via a cleavable ester linkage. JQ-FT is recognized by folate receptors on the plasma membrane and delivered into leukemia cells as a potent antileukemic agent. In mechanistic and translational models of T-ALL, we demonstrate NOTCH1 inhibition in vitro and in vivo. These proof-of-concept studies support the further optimization of this first-in-class NOTCH1 inhibitor with dual selectivity: leukemia over normal cells and NOTCH1 mutants over wild-type receptors. Furthermore, tumor-specific disruption of Notch signaling may overcome legitimate concerns associated with the tumor suppressor function of nontargeted Notch pathway inhibitors.
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Affiliation(s)
- Giovanni Roti
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA.,Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA.,Department of Medicine and Surgery, University of Parma, Italy
| | - Jun Qi
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Samuel Kitara
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA.,Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA
| | | | - Amy Saur Conway
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA.,Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA
| | - Anthony C Varca
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Angela Su
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA.,Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA
| | - Lei Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Andrew L Kung
- Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, NY
| | | | - James E Bradner
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA .,Department of Medicine, Harvard Medical School, Boston, MA.,Novartis Institutes for Biomedical Research, Cambridge, MA
| | - Kimberly Stegmaier
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA .,Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA.,Broad Institute, Cambridge, MA
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19
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Michaeli L, Gottfried I, Bykhovskaia M, Ashery U. Phosphatidylinositol (4, 5)-bisphosphate targets double C2 domain protein B to the plasma membrane. Traffic 2017; 18:825-839. [PMID: 28941037 DOI: 10.1111/tra.12528] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 01/05/2023]
Abstract
Double C2 domain protein B (DOC2B) is a high-affinity Ca2+ sensor that translocates from the cytosol to the plasma membrane (PM) and promotes vesicle priming and fusion. However, the molecular mechanism underlying its translocation and targeting to the PM in living cells is not completely understood. DOC2B interacts in vitro with the PM components phosphatidylserine, phosphatidylinositol (4, 5)-bisphosphate [PI(4, 5)P2 ] and target SNAREs (t-SNAREs). Here, we show that PI(4, 5)P2 hydrolysis at the PM of living cells abolishes DOC2B translocation, whereas manipulations of t-SNAREs and other phosphoinositides have no effect. Moreover, we were able to redirect DOC2B to intracellular membranes by synthesizing PI(4, 5)P2 in those membranes. Molecular dynamics simulations and mutagenesis in the calcium and PI(4, 5)P2 -binding sites strengthened our findings, demonstrating that both calcium and PI(4, 5)P2 are required for the DOC2B-PM association and revealing multiple PI(4, 5)P2 -C2B interactions. In addition, we show that DOC2B translocation to the PM is ATP-independent and occurs in a diffusion-like manner. Our data suggest that the Ca2+ -triggered translocation of DOC2B is diffusion-driven and aimed at PI(4, 5)P2 -containing membranes.
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Affiliation(s)
- Lirin Michaeli
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Irit Gottfried
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | | | - Uri Ashery
- Department of Neurobiology, Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
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20
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Demonstration of the Protein Involvement in Cell Electropermeabilization using Confocal Raman Microspectroscopy. Sci Rep 2017; 7:40448. [PMID: 28102326 PMCID: PMC5244372 DOI: 10.1038/srep40448] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 12/06/2016] [Indexed: 01/14/2023] Open
Abstract
Confocal Raman microspectroscopy was used to study the interaction between pulsed electric fields and live cells from a molecular point of view in a non-invasive and label-free manner. Raman signatures of live human adipose-derived mesenchymal stem cells exposed or not to pulsed electric fields (8 pulses, 1 000 V/cm, 100 μs, 1 Hz) were acquired at two cellular locations (nucleus and cytoplasm) and two spectral bands (600–1 800 cm−1 and 2 800–3 100 cm−1). Vibrational modes of proteins (phenylalanine and amide I) and lipids were found to be modified by the electropermeabilization process with a statistically significant difference. The relative magnitude of four phenylalanine peaks decreased in the spectra of the pulsed group. On the contrary, the relative magnitude of the amide I band at 1658 cm−1 increased by 40% when comparing pulsed and control group. No difference was found between the control and the pulsed group in the high wavenumber spectral band. Our results reveal the modification of proteins in living cells exposed to pulsed electric fields by means of confocal Raman microspectroscopy.
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21
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Ruggiero FM, Vilcaes AA, Yuki N, Daniotti JL. Membrane binding, endocytic trafficking and intracellular fate of high-affinity antibodies to gangliosides GD1a and GM1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:80-93. [DOI: 10.1016/j.bbamem.2016.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 11/25/2022]
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22
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Savio MG, Wollscheid N, Cavallaro E, Algisi V, Di Fiore PP, Sigismund S, Maspero E, Polo S. USP9X Controls EGFR Fate by Deubiquitinating the Endocytic Adaptor Eps15. Curr Biol 2016; 26:173-183. [PMID: 26748853 DOI: 10.1016/j.cub.2015.11.050] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/16/2015] [Accepted: 11/20/2015] [Indexed: 01/16/2023]
Abstract
Following activation by its cognate ligand(s), the epidermal growth factor receptor (EGFR) is rapidly routed to the lysosome for degradation in a ubiquitination-dependent fashion. This pathway represents the major mechanism of long-term attenuation of EGFR signaling, and its deregulation is a significant feature in different types of cancers. Here we demonstrate, through a systematic RNAi-based approach, that several deubiquitinating (DUB) enzymes extend or decrease EGFR half-life upon EGF stimulation. We focus on USP9X, whose depletion severely affects EGFR turnover, interfering with its internalization and trafficking. We identify the endocytic protein Eps15 as one of the critical substrates of USP9X, and we map the Eps15 ubiquitination sites. We found that Eps15 monoubiquitination occurs already at minimal dose of EGF stimulation and is essential for EGFR internalization. Overall, our findings identify USP9X as a novel regulator of EGFR endocytosis and suggest a model whereby cycles of ubiquitination and deubiquitination events on endocytic accessory proteins may regulate the internalization and trafficking of the EGFR toward the lysosomes.
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Affiliation(s)
- Michol Giovanna Savio
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy; DIPO, Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Via di Rudinì 8, 20122 Milan, Italy
| | - Nadine Wollscheid
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Elena Cavallaro
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Veronica Algisi
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Pier Paolo Di Fiore
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy; DIPO, Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Via di Rudinì 8, 20122 Milan, Italy; IEO, Istituto Europeo di Oncologia, Via Ripamonti 435, 20141 Milan, Italy
| | - Sara Sigismund
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Elena Maspero
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy
| | - Simona Polo
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139 Milan, Italy; DIPO, Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Via di Rudinì 8, 20122 Milan, Italy.
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23
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Guerrero YA, Bahmani B, Singh SP, Vullev VI, Kundra V, Anvari B. Virus-resembling nano-structures for near infrared fluorescence imaging of ovarian cancer HER2 receptors. NANOTECHNOLOGY 2015; 26:435102. [PMID: 26443474 DOI: 10.1088/0957-4484/26/43/435102] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ovarian cancer remains the dominant cause of death due to malignancies of the female reproductive system. The capability to identify and remove all tumors during intraoperative procedures may ultimately reduce cancer recurrence, and lead to increased patient survival. The objective of this study is to investigate the effectiveness of an optical nano-structured system for targeted near infrared (NIR) imaging of ovarian cancer cells that over-express the human epidermal growth factor receptor 2 (HER2), an important biomarker associated with ovarian cancer. The nano-structured system is comprised of genome-depleted plant-infecting brome mosaic virus doped with NIR chromophore, indocyanine green, and functionalized at the surface by covalent attachment of monoclonal antibodies against the HER2 receptor. We use absorption and fluorescence spectroscopy, and dynamic light scattering to characterize the physical properties of the constructs. Using fluorescence imaging and flow cytometry, we demonstrate the effectiveness of these nano-structures for targeted NIR imaging of HER2 receptors in vitro. These functionalized nano-materials may provide a platform for NIR imaging of ovarian cancer.
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Affiliation(s)
- Yadir A Guerrero
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
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24
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Liu HY, Huang CM, Hung YF, Hsueh YP. The microRNAs Let7c and miR21 are recognized by neuronal Toll-like receptor 7 to restrict dendritic growth of neurons. Exp Neurol 2015; 269:202-12. [PMID: 25917529 DOI: 10.1016/j.expneurol.2015.04.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 04/14/2015] [Accepted: 04/15/2015] [Indexed: 11/25/2022]
Abstract
Inflammatory responses are known to play critical roles in the regulation of neurodevelopment and neurodegeneration. Although microglial cells are recognized as professional immune cells in brains, recent evidence suggests that neurons also express important receptors and regulators of innate immunity, including Toll-like receptor 7 (TLR7), which is a receptor for single-stranded RNAs (ssRNAs). Here, we report that neuronal TLR7 recognizes endogenous ligands such as the miRNAs Let7c and miR21 and plays a negative role in controlling neuronal growth in a cell-autonomous manner. We show here that hippocampal CA1 neurons in Tlr7(-/Y) mice had more complex dendritic arbors compared with those of wild-type littermates at postnatal (P) day 7, but not at P21. This observation strengthens a role of TLR7 in restricting neuronal growth during development. In cultured neurons, transient knockdown of Tlr7 promoted axonal and dendritic growth, supporting the cell-autonomous effect of TLR7 on neuronal growth. We observed perceptible levels of Let7c and miR21 in the exosomes of the neuronal cultures as well as in developing brains. Treatment with Let7c and miR21 restricted dendritic growth of wild-type neurons but not Tlr7(-/-) neurons. Our study suggests that neuronal TLR7 is activated by endogenous ligands and thus regulates neuronal morphology. Neuronal innate immune responses may influence neurodevelopment and neurodegeneration through the regulation of neuronal morphology.
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Affiliation(s)
- Hsin-Yu Liu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
| | | | - Yun-Fen Hung
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan.
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25
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Arthur G, Schweizer F, Ogunsina M. Synthetic Glycosylated Ether Glycerolipids as Anticancer Agents. CARBOHYDRATES IN DRUG DESIGN AND DISCOVERY 2015. [DOI: 10.1039/9781849739993-00151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Glycosylated antitumor ether lipids (GAELs) are a class of synthetic antitumor ether lipids (AELs) with a sugar moiety in place of the phosphocholine found in the prototypical AEL, edelfosine. This chapter reviews the development of GAELs as antitumor agents. Studies on structure–activity relationships, mechanism of induction of cell death, metabolism, selectivity against cancer cells, toxicity, hemolysis and thrombogenic effects are discussed. The requirements for significant cytotoxic activity include a glycerol moiety, a cationic sugar other than mannose and an O- or C-glycosidic bond with either α- or β-configuration. Compounds with S- and N-glycosidic linkages are not very active. The most active GAEL to date, 1-O-hexadecyl-2-O-methyl-3-O-(2′-amino-2′-deoxy-α-d-galactopyranosyl)-sn-glycerol, displays greater in vitro activity than edelfosine, the AEL “gold standard”. The unique properties of GAELs as antitumor agents include their apoptotic-independent mechanism of inducing cell death and the ability to kill cancer stem cells. These characteristics of GAELs offer the potential for their development into chemotherapeutic agents to prevent the recurrence of tumors as well as for treatment against drug-resistant cancers.
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Affiliation(s)
- Gilbert Arthur
- Department of Biochemistry and Medical Genetics, University of Manitoba 754 Bannatyne Avenue Winnipeg, Manitoba Canada R3E 0J9
| | - Frank Schweizer
- Department of Chemistry and Medical Microbiology, University of Manitoba 460 Parker Building Winnipeg, Manitoba Canada R3T 2N2
| | - Makanjuola Ogunsina
- Department of Chemistry and Medical Microbiology, University of Manitoba 460 Parker Building Winnipeg, Manitoba Canada R3T 2N2
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Trypanosoma cruzi, etiological agent of Chagas disease, is virulent to its triatomine vector Rhodnius prolixus in a temperature-dependent manner. PLoS Negl Trop Dis 2015; 9:e0003646. [PMID: 25793495 PMCID: PMC4368190 DOI: 10.1371/journal.pntd.0003646] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 02/25/2015] [Indexed: 12/05/2022] Open
Abstract
It is often assumed that parasites are not virulent to their vectors. Nevertheless, parasites commonly exploit their vectors (nutritionally for example) so these can be considered a form of host. Trypanosoma cruzi, a protozoan found in mammals and triatomine bugs in the Americas, is the etiological agent of Chagas disease that affects man and domestic animals. While it has long been considered avirulent to its vectors, a few reports have indicated that it can affect triatomine fecundity. We tested whether infection imposed a temperature-dependent cost on triatomine fitness. We held infected insects at four temperatures between 21 and 30°C and measured T. cruzi growth in vitro at the same temperatures in parallel. Trypanosoma cruzi infection caused a considerable delay in the time the insects took to moult (against a background effect of temperature accelerating moult irrespective of infection status). Trypanosoma cruzi also reduced the insects’ survival, but only at the intermediate temperatures of 24 and 27°C (against a background of increased mortality with increasing temperatures). Meanwhile, in vitro growth of T. cruzi increased with temperature. Our results demonstrate virulence of a protozoan agent of human disease to its insect vector under these conditions. It is of particular note that parasite-induced mortality was greatest over the range of temperatures normally preferred by these insects, probably implying adaptation of the parasite to perform well at these temperatures. Therefore we propose that triggering this delay in moulting is adaptive for the parasites, as it will delay the next bloodmeal taken by the bug, thus allowing the parasites time to develop and reach the insect rectum in order to make transmission to a new vertebrate host possible. Parasites are often assumed to cause little harm to their arthropod vectors, even though they commonly reproduce inside the arthropods and exploit their nutrients, even causing lesions when crossing internal barriers. Thus, the interests of parasite and vector may well not be aligned and we can expect the parasite to exploit its vector just as it does with its main host, with consequent negative effects on the vector’s fitness. Here, we show that this occurs with Trypanosoma cruzi in its bug vector (T. cruzi causes Chagas disease, affecting ca. 8 million people and disease management is principally attained via vector control). Our results indicate that the parasites delay insect moulting, which is likely beneficial to them as they need time to develop in the insect before the next bloodmeal (that only occurs post-moult). We also show parasite-induced mortality over the narrow range of temperatures which the insect prefers and over which it performs best. In vitro growth of the parasite increases with temperature and we discuss how this may help explain the effects in vivo. Overall, these results will be important to understand the epidemiology of Chagas disease and provide an evolutionary context to explain the parasite′s interaction with its vector.
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Oh S, Lee BF, Leibfarth FA, Eisenstein M, Robb MJ, Lynd N, Hawker CJ, Soh HT. Synthetic aptamer-polymer hybrid constructs for programmed drug delivery into specific target cells. J Am Chem Soc 2014; 136:15010-5. [PMID: 25290917 PMCID: PMC4210129 DOI: 10.1021/ja5079464] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Indexed: 12/11/2022]
Abstract
Viruses have evolved specialized mechanisms to efficiently transport nucleic acids and other biomolecules into specific host cells. They achieve this by performing a coordinated series of complex functions, resulting in delivery that is far more efficient than existing synthetic delivery mechanisms. Inspired by these natural systems, we describe a process for synthesizing chemically defined molecular constructs that likewise achieve targeted delivery through a series of coordinated functions. We employ an efficient "click chemistry" technique to synthesize aptamer-polymer hybrids (APHs), coupling cell-targeting aptamers to block copolymers that secure a therapeutic payload in an inactive state. Upon recognizing the targeted cell-surface marker, the APH enters the host cell via endocytosis, at which point the payload is triggered to be released into the cytoplasm. After visualizing this process with coumarin dye, we demonstrate targeted killing of tumor cells with doxorubicin. Importantly, this process can be generalized to yield APHs that specifically target different surface markers.
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Affiliation(s)
- Seung
Soo Oh
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
| | - Bongjae F. Lee
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
- Chemical
Research Institute, Samsung Cheil Industries,
Inc., Seoul, Republic
of Korea 140739
| | - Frank A. Leibfarth
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
| | - Michael Eisenstein
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
| | - Maxwell J. Robb
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
| | - Nathaniel
A. Lynd
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
| | - Craig J. Hawker
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
| | - H. Tom Soh
- Materials Department, Department of Chemistry and Biochemistry, Department of Mechanical
Engineering, Materials Research Laboratory, University
of California, Santa Barbara, California 93106, United States
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Frittoli E, Palamidessi A, Marighetti P, Confalonieri S, Bianchi F, Malinverno C, Mazzarol G, Viale G, Martin-Padura I, Garré M, Parazzoli D, Mattei V, Cortellino S, Bertalot G, Di Fiore PP, Scita G. A RAB5/RAB4 recycling circuitry induces a proteolytic invasive program and promotes tumor dissemination. ACTA ACUST UNITED AC 2014; 206:307-28. [PMID: 25049275 PMCID: PMC4107781 DOI: 10.1083/jcb.201403127] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The mechanisms by which tumor cells metastasize and the role of endocytic proteins in this process are not well understood. We report that overexpression of the GTPase RAB5A, a master regulator of endocytosis, is predictive of aggressive behavior and metastatic ability in human breast cancers. RAB5A is necessary and sufficient to promote local invasion and distant dissemination of various mammary and nonmammary tumor cell lines, and this prometastatic behavior is associated with increased intratumoral cell motility. Specifically, RAB5A is necessary for the formation of invadosomes, membrane protrusions specialized in extracellular matrix (ECM) degradation. RAB5A promotes RAB4- and RABENOSYN-5-dependent endo/exocytic cycles (EECs) of critical cargos (membrane-type 1 matrix metalloprotease [MT1-MMP] and β3 integrin) required for invadosome formation in response to motogenic stimuli. This trafficking circuitry is necessary for spatially localized hepatocyte growth factor (HGF)/MET signaling that drives invasive, proteolysis-dependent chemotaxis in vitro and for conversion of ductal carcinoma in situ to invasive ductal carcinoma in vivo. Thus, RAB5A/RAB4 EECs promote tumor dissemination by controlling a proteolytic, mesenchymal invasive program.
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Affiliation(s)
- Emanuela Frittoli
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy
| | - Andrea Palamidessi
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy
| | - Paola Marighetti
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy
| | - Stefano Confalonieri
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | - Fabrizio Bianchi
- Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | - Chiara Malinverno
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy
| | - Giovanni Mazzarol
- Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | - Giuseppe Viale
- Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | - Ines Martin-Padura
- Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | | | - Dario Parazzoli
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy
| | - Valentina Mattei
- Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | | | - Giovanni Bertalot
- Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy
| | - Pier Paolo Di Fiore
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia, 20141 Milan, Italy Dipartimento di Scienze della Salute, Università degli Studi di Milano, 20122 Milan, Italy
| | - Giorgio Scita
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), 20139 Milan, Italy Dipartimento di Scienze della Salute, Università degli Studi di Milano, 20122 Milan, Italy
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HIV-1 entry in SupT1-R5, CEM-ss, and primary CD4+ T cells occurs at the plasma membrane and does not require endocytosis. J Virol 2014; 88:13956-70. [PMID: 25253335 DOI: 10.1128/jvi.01543-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED Cytoplasmic entry of HIV-1 requires binding of the viral glycoproteins to the cellular receptor and coreceptor, leading to fusion of viral and cellular membranes. Early studies suggested that productive HIV-1 infection occurs by direct fusion at the plasma membrane. Endocytotic uptake of HIV-1 was frequently observed but was considered to constitute an unspecific dead-end pathway. More recent evidence suggested that endocytosis contributes to productive HIV-1 entry and may even represent the predominant or exclusive route of infection. We have analyzed HIV-1 binding, endocytosis, cytoplasmic entry, and infection in T-cell lines and in primary CD4(+) T cells. Efficient cell binding and endocytosis required viral glycoproteins and CD4, but not the coreceptor. The contribution of endocytosis to cytoplasmic entry and infection was assessed by two strategies: (i) expression of dominant negative dynamin-2 was measured and was found to efficiently block HIV-1 endocytosis but to not affect fusion or productive infection. (ii) Making use of the fact that HIV-1 fusion is blocked at temperatures below 23 °C, cells were incubated with HIV-1 at 22 °C for various times, and endocytosis was quantified by parallel analysis of transferrin and fluorescent HIV-1 uptake. Subsequently, entry at the plasma membrane was blocked by high concentrations of the peptidic fusion inhibitor T-20, which does not reach previously endocytosed particles. HIV-1 infection was scored after cells were shifted to 37 °C in the presence of T-20. These experiments revealed that productive HIV-1 entry occurs predominantly at the plasma membrane in SupT1-R5, CEM-ss, and primary CD4(+) T cells, with little, if any, contribution coming from endocytosed virions. IMPORTANCE HIV-1, like all enveloped viruses, reaches the cytoplasm by fusion of the viral and cellular membranes. Many viruses enter the cytoplasm by endosomal uptake and fusion from the endosome, while cell entry can also occur by direct fusion at the plasma membrane in some cases. Conflicting evidence regarding the site of HIV-1 fusion has been reported, with some studies claiming that fusion occurs predominantly at the plasma membrane, while others have suggested predominant or even exclusive fusion from the endosome. We have revisited HIV-1 entry using a T-cell line that exhibits HIV-1 endocytosis dependent on the viral glycoproteins and the cellular CD4 receptor; results with this cell line were confirmed for another T-cell line and primary CD4(+) T cells. Our studies show that fusion and productive entry occur predominantly at the plasma membrane, and we conclude that endocytosis is dispensable for HIV-1 infectivity in these T-cell lines and in primary CD4(+) T cells.
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Gordillo GJ, Krpetić Z, Brust M. Interactions of gold nanoparticles with a phospholipid monolayer membrane on mercury. ACS NANO 2014; 8:6074-80. [PMID: 24878256 DOI: 10.1021/nn501395e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
It is demonstrated that a compact monolayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine adsorbed to a hanging mercury drop electrode can serve as a simple electrochemical model system to study biomembrane penetration by gold nanoparticles. The hydrogen redox-chemistry characteristic of ligand-stabilized gold nanoparticles in molecularly close contact with a mercury electrode is used as an indicator of membrane penetration. Results for water-dispersible gold nanoparticles of two different sizes are reported, and comparisons are made with the cellular uptake of the same preparations of nanoparticles by a common human fibroblast cell line. The experimental system described here can be used to study physicochemical aspects of membrane penetration in the absence of complex biological mechanisms, and it could also be a starting point for the development of a test bed for the toxicity of nanomaterials.
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Affiliation(s)
- Gabriel J Gordillo
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, INQUIMAE (CONICET), Universidad de Buenos Aires , Ciudad Universitaria, Pabellón 2, 1428, Buenos Aires, Argentina
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Commisso C, Flinn RJ, Bar-Sagi D. Determining the macropinocytic index of cells through a quantitative image-based assay. Nat Protoc 2014; 9:182-92. [PMID: 24385148 DOI: 10.1038/nprot.2014.004] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Macropinocytosis serves as an internalization pathway for extracellular fluid and its contents. Macropinocytosis is upregulated in oncogene-expressing cells and, recently, we have revealed a functional role for macropinocytosis in fueling cancer cell growth through the internalization of extracellular albumin, which is degraded into a usable source of intracellular amino acids. Assessing macropinocytosis has been challenging in the past because of the lack of reliable assays capable of quantitatively measuring this uptake mechanism. Here we describe a protocol for visualizing and quantifying the extent of macropinocytosis in cells both in culture and growing in vivo as tumor xenografts. By using this approach, the 'macropinocytic index' of a particular cell line or subcutaneous tumor can be ascertained within 1-2 d. The protocol can be carried out with multiple samples in parallel and can be easily adapted for a variety of cell types and xenograft or allograft mouse models.
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Affiliation(s)
- Cosimo Commisso
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Rory J Flinn
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Dafna Bar-Sagi
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
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A Mason-Pfizer Monkey virus Gag-GFP fusion vector allows visualization of capsid transport in live cells and demonstrates a role for microtubules. PLoS One 2013; 8:e83863. [PMID: 24386297 PMCID: PMC3873405 DOI: 10.1371/journal.pone.0083863] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Accepted: 11/10/2013] [Indexed: 11/19/2022] Open
Abstract
Immature capsids of the Betaretrovirus, Mason-Pfizer Monkey virus (M-PMV), are assembled in the pericentriolar region of the cell, and are then transported to the plasma membrane for budding. Although several studies, utilizing mutagenesis, biochemistry, and immunofluorescence, have defined the role of some viral and host cells factors involved in these processes, they have the disadvantage of population analysis, rather than analyzing individual capsid movement in real time. In this study, we created an M-PMV vector in which the enhanced green fluorescent protein, eGFP, was fused to the carboxyl-terminus of the M-PMV Gag polyprotein, to create a Gag-GFP fusion that could be visualized in live cells. In order to express this fusion protein in the context of an M-PMV proviral backbone, it was necessary to codon-optimize gag, optimize the Kozak sequence preceding the initiating methionine, and mutate an internal methionine codon to one for alanine (M100A) to prevent internal initiation of translation. Co-expression of this pSARM-Gag-GFP-M100A vector with a WT M-PMV provirus resulted in efficient assembly and release of capsids. Results from fixed-cell immunofluorescence and pulse-chase analyses of wild type and mutant Gag-GFP constructs demonstrated comparable intracellular localization and release of capsids to untagged counterparts. Real-time, live-cell visualization and analysis of the GFP-tagged capsids provided strong evidence for a role for microtubules in the intracellular transport of M-PMV capsids. Thus, this M-PMV Gag-GFP vector is a useful tool for identifying novel virus-cell interactions involved in intracellular M-PMV capsid transport in a dynamic, real-time system.
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Congdon EE, Gu J, Sait HBR, Sigurdsson EM. Antibody uptake into neurons occurs primarily via clathrin-dependent Fcγ receptor endocytosis and is a prerequisite for acute tau protein clearance. J Biol Chem 2013; 288:35452-65. [PMID: 24163366 DOI: 10.1074/jbc.m113.491001] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Tau immunotherapy is effective in transgenic mice, but the mechanisms of Tau clearance are not well known. To this end, Tau antibody uptake was analyzed in brain slice cultures and primary neurons. Internalization was rapid (<1 h), saturable, and substantial compared with control mouse IgG. Furthermore, temperature reduction to 4 °C, an excess of unlabeled mouse IgG, or an excess of Tau antibodies reduced uptake in slices by 63, 41, and 62%, respectively (p = 0.002, 0.04, and 0.005). Uptake strongly correlated with total and insoluble Tau levels (r(2) = 0.77 and 0.87 and p = 0.002 and 0.0002), suggesting that Tau aggregates influence antibody internalization and/or retention within neurons. Inhibiting phagocytosis did not reduce uptake in slices or neuronal cultures, indicating limited microglial involvement. In contrast, clathrin-specific inhibitors reduced uptake in neurons (≤ 78%, p < 0.0001) and slices (≤ 35%, p = 0.03), demonstrating receptor-mediated endocytosis as the primary uptake pathway. Fluid phase endocytosis accounted for the remainder of antibody uptake in primary neurons, based on co-staining with internalized dextran. The receptor-mediated uptake is to a large extent via low affinity FcγII/III receptors and can be blocked in slices (43%, p = 0.04) and neurons (53%, p = 0.008) with an antibody against these receptors. Importantly, antibody internalization appears to be necessary for Tau reduction in primary neurons. Overall, these findings clarify that Tau antibody uptake is primarily receptor-mediated, that these antibodies are mainly found in neurons with Tau aggregates, and that their intracellular interaction leads to clearance of Tau pathology, all of which have major implications for therapeutic development of this approach.
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Kettiger H, Schipanski A, Wick P, Huwyler J. Engineered nanomaterial uptake and tissue distribution: from cell to organism. Int J Nanomedicine 2013; 8:3255-69. [PMID: 24023514 PMCID: PMC3767489 DOI: 10.2147/ijn.s49770] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Improved understanding of interactions between nanoparticles and biological systems is needed to develop safety standards and to design new generations of nanomaterials. This article reviews the molecular mechanisms of cellular uptake of engineered nanoparticles, their intracellular fate, and their distribution within an organism. We have reviewed the available literature on the uptake and disposition of engineered nanoparticles. Special emphasis was placed on the analysis of experimental systems and their limitations with respect to their usefulness to predict the in vivo situation. The available literature confirms the need to study particle characteristics in an environment that simulates the situation encountered in biological systems. Phenomena such as protein binding and opsonization are of prime importance since they may have a strong impact on cellular internalization, biodistribution, and immunogenicity of nanoparticles in vitro and in vivo. Extrapolation from in vitro results to the in vivo situation in the whole organism remains a challenge. However, improved understanding of physicochemical properties of engineered nanoparticles and their influence on biological systems facilitates the design of nanomaterials that are safe, well tolerated, and suitable for diagnostic or therapeutic use in humans.
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Affiliation(s)
- Helene Kettiger
- Department of Pharmaceutical Sciences, Division of Pharmaceutical Technology, University of Basel, Basel, Switzerland
| | - Angela Schipanski
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Materials-Biology Interactions, St Gallen, Switzerland
| | - Peter Wick
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Materials-Biology Interactions, St Gallen, Switzerland
| | - Jörg Huwyler
- Department of Pharmaceutical Sciences, Division of Pharmaceutical Technology, University of Basel, Basel, Switzerland
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Qin B, Chen Z, Jin W, Cheng K. Development of cholesteryl peptide micelles for siRNA delivery. J Control Release 2013; 172:159-168. [PMID: 23968830 DOI: 10.1016/j.jconrel.2013.07.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 06/26/2013] [Accepted: 07/30/2013] [Indexed: 12/27/2022]
Abstract
Despite the rapid progress in the siRNA field, developing a safe and efficient delivery system of siRNA remains to be an obstacle in the therapeutical application of siRNA. The purpose of this study is to develop an efficient peptide-based siRNA delivery system for cancer therapy. To this end, cholesterol was conjugated to a series of peptides composed of lysine and histidine residues. The resultant cholesteryl peptides were characterized, and their potential for siRNA delivery was evaluated. Our results indicate that short peptides (11-21 mer) composed of various numbers of lysine and histidine residues alone are not sufficient to mediate efficient siRNA delivery. However, the amphiphilic cholesteryl peptides can self-assemble to form a micelle-like structure in aqueous solutions, which significantly promotes the siRNA condensation capability of the peptides. The cholesteryl peptides form stable complex with siRNA and effectively protect siRNA from degradation in rat serum up to three days. Furthermore, the cholesteryl peptides efficiently transfect siRNA into different cancer cells and trigger potent gene silencing effect, whereas peptides without cholesterol modification cannot deliver siRNA into the cells. In addition, one of the cholesteryl peptides Chol-H3K2s displays comparable cellular uptake and gene silencing effect but less cytotoxicity compared with branched polyethylenimine (bPEI) and Lipofectamine-2000. Our results reveal that the cholesteryl peptides possess great potential as an efficient siRNA delivery system.
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Affiliation(s)
- Bin Qin
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Zhijin Chen
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Wei Jin
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
| | - Kun Cheng
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA.
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Kapoor M, Burgess DJ. Cellular uptake mechanisms of novel anionic siRNA lipoplexes. Pharm Res 2012; 30:1161-75. [PMID: 23239010 DOI: 10.1007/s11095-012-0952-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 11/30/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE To investigate cellular uptake pathways of novel anionic siRNA-lipoplexes as a function of formulation composition. METHODS Anionic formulations with anionic lipid/Ca(2+)/siRNA ratio of 1.3/2.5/1 (AF1) and 1.3/0.3/1 (AF2) were utilized. Uptake mechanisms were investigated using uptake inhibition and co-localization approaches in breast cancer cells. Actin-mediated uptake was investigated using actin polymerization and rearrangement assays. Silencing efficiency and endosomal escaping capability of lipoplexes were evaluated. The cationic formulation Lipofectamine-2000 was used as a control. RESULTS Anionic lipoplexes entered the breast cancer cells via endocytosis specifically via macropinocytosis or via both macropinocytosis and HSPG (heparin sulfate proteoglycans) pathways, depending on the Ca(2+)/siRNA ratio. Additionally, uptake of these lipoplexes was both microtubule and actin dependent. The control cationic lipid-siRNA complexes (Lipofectamine-2000) were internalized via both endocytic (phagocytosis, HSPG) and non-endocytic (membrane fusion) pathways. Their uptake was microtubule independent but actin dependent. Silencing efficiency of the AF2 formulation was negligible mainly due to poor endosomal release (rate-limiting step). CONCLUSIONS Formulation composition significantly influences the internalization mechanism of anionic lipoplexes. Uptake mechanism together with formulation bioactivity helped in identification of the rate-limiting steps to efficient siRNA delivery. Such studies are extremely useful for formulation optimization to achieve enhanced intracellular delivery of nucleic acids.
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Affiliation(s)
- Mamta Kapoor
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, 69 N Eagleville Rd, Unit 3092, Storrs, Connecticut 06269, USA
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German CL, Sauer BM, Howe CL. The STAT3 beacon: IL-6 recurrently activates STAT 3 from endosomal structures. Exp Cell Res 2011; 317:1955-69. [PMID: 21619877 DOI: 10.1016/j.yexcr.2011.05.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 05/10/2011] [Accepted: 05/10/2011] [Indexed: 01/12/2023]
Abstract
Endocytic trafficking plays an important role in signal transduction. Signal transducer and activator of transcription 3 (STAT3) and mitogen-activate protein kinase (MAPK) have both been localized to endosomal structures and are dependent upon endocytosis for downstream function. While the dependence of MAPK signaling upon endosomes has been well characterized, the involvement of endosomes in regulating STAT3 signaling has not been defined. Consequently, this study evaluated the role of endosomes in the initiation, modulation, amplification and persistence of interleukin-6(IL-6)-induced STAT3 signal transduction and transcription, and utilized IL-6-induced MAPK signaling as a comparator. Using pharmacologic treatment and temperature control of endocytic trafficking, pulse-chase treatments and in vitro kinase assays, STAT3 was found to interact with endosomes in a markedly different fashion than MAPK. STAT3 was activated by direct interaction with internal structures upstream of the late endosome following IL-6 exposure and persistent STAT3 signaling depended upon recurrent activation from endocytic structures. Further, STAT3 subcellular localization was not dependent upon endocytic trafficking. Instead, STAT3 transiently interacted with endosomes and relocated to the nucleus by an endosome-independent mechanism. Finally, endocytic trafficking played a central role in regulating STAT3 serine 727 phosphorylation through crosstalk with the MAPK signaling system. Together, these data reveal endosomes as central to the genesis, course and outcome of STAT3 signal transduction and transcription.
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Affiliation(s)
- Christopher L German
- Program in Molecular Neuroscience, Mayo Clinic College of Medicine, 200 First ST SW, Rochester, MN 55905, USA.
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Zoldakova M, Kornyei Z, Brown A, Biersack B, Madarász E, Schobert R. Effects of a combretastatin A4 analogous chalcone and its Pt-complex on cancer cells: A comparative study of uptake, cell cycle and damage to cellular compartments. Biochem Pharmacol 2010; 80:1487-96. [PMID: 20709029 DOI: 10.1016/j.bcp.2010.07.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2010] [Revised: 07/23/2010] [Accepted: 07/27/2010] [Indexed: 01/11/2023]
Abstract
The combretastatin A4 analogous chalcone (2E)-3-(3-hydroxy-4-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one 1 and its dichloridoplatinum(II) (6-aminomethylnicotinate) complex 2 were previously found to be highly active against a variety of cancer cell lines while differing in their apoptosis induction and long-term regrowth retardation (Schobert et al. [1]). Further differences were identified now. The cellular uptake of complex 2, like that of oxaliplatin, occurred mainly via organic cation transporters (OCT-1/2; ∼32%) and copper transporter related proteins (Ctr1; ∼24%), whereas that of chalcone 1 was dependent on endocytosis (∼80%). Complex 2 was more tumour-specific than 1 concerning neural cells. This was apparent from the ratios of IC(50)(48h) values against primary astrocytes versus human glioma cells U87 (>7000 for complex 2; 55 for compound 1). In tubulin-rich neurons and 518A2 melanoma cells complex 2 disrupted microtubules and actin filaments. Cancer cells treated with 2 could repair the cytoskeletal damage but ceased to proliferate and perished. Complex 2 was particularly cytotoxic against P-gp-rich cells. It acted as a substrate for ABC-transporters of types BCRP, MRP3, and MRP1 and so was less active against the corresponding cancer cell lines. Complex 2 arrested the cell cycle of the melanoma cells in G(1) and G(2)/M phases. A fragmentation of their Golgi apparatus was observed by TEM for incubation with complex 2 but not with 1. In conclusion, unlike chalcone 1, its platinum complex 2 is highly cell line specific, is taken up via cell-controlled transporters and induces apoptosis by triggering multiple targets.
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Affiliation(s)
- Miroslava Zoldakova
- Organic Chemistry Laboratory, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
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Abstract
Although the critical role of T-cell receptor (TCR) microclusters in T-cell activation is now widely accepted, the mechanisms of regulation of these TCR-rich structures, which also contain enzymes, adapters, and effectors, remain poorly defined. Soon after microcluster formation, several signaling proteins rapidly dissociate from the TCR. Recent studies from our laboratory demonstrated that the movement of the adapters linker for activation of T cells (LAT) and Src homology 2 domain-containing leukocyte protein of 76 kDa (SLP-76) away from initial microcluster formation sites represents endocytic events. Ubiquitylation, Cbl proteins, and multiple endocytic pathways are involved in the internalization events that disassemble signaling microclusters. Several recent studies have indicated that microcluster movement and centralization plays an important role in signal termination. We suggest that microcluster movement is directly linked to endocytic events, thus implicating endocytosis of microclusters as a means to regulate signaling output of the T cell.
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Affiliation(s)
- Lakshmi Balagopalan
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Valarie A. Barr
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lawrence E. Samelson
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Visualization of Ras-PI3K interaction in the endosome using BiFC. Cell Signal 2009; 21:1672-9. [PMID: 19616621 DOI: 10.1016/j.cellsig.2009.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 07/09/2009] [Indexed: 11/22/2022]
Abstract
Recent studies indicate the importance of spatiotemporal regulation in the diversity and specificity of intracellular signaling. Here, we show that Ras-PI3K signaling plays an important role in the local regulation of phosphatidylinositol metabolism in the endosome through live-cell imaging by using a bimolecular fluorescence complementation technique, in which molecular interaction is indicated by fluorescence emission. Using several possible combinations of Ras and the Ras-binding domain, we identified an optimal set of probe molecules that yielded the most significant increase in fluorescence intensity between the active and inactive forms of Ras. This combination revealed that, among the Ras effectors tested, phosphatidylinositol 3-kinase (PI3K) was specifically implicated in signaling in the endosome. We also found that full length PI3K was recruited to the endosome in EGF- and Ras-dependent manners, which appears to be essential for the activation of PI3K in this compartment. Taken together, these findings demonstrate that the spatiotemporal regulation of Ras-PI3K signaling may dictate the activation of PI3K and subsequent downstream signaling in the endosome.
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Stirling L, Williams MR, Morielli AD. Dual roles for RHOA/RHO-kinase in the regulated trafficking of a voltage-sensitive potassium channel. Mol Biol Cell 2009; 20:2991-3002. [PMID: 19403695 DOI: 10.1091/mbc.e08-10-1074] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Kv1.2 is a member of the Shaker family of voltage-sensitive potassium channels and contributes to regulation of membrane excitability. The electrophysiological activity of Kv1.2 undergoes tyrosine kinase-dependent suppression in a process involving RhoA. We report that RhoA elicits suppression of Kv1.2 ionic current by modulating channel endocytosis. This occurs through two distinct pathways, one clathrin-dependent and the other cholesterol-dependent. Activation of Rho kinase (ROCK) via the lysophosphatidic acid (LPA) receptor elicits clathrin-dependent Kv1.2 endocytosis and consequent attenuation of its ionic current. LPA-induced channel endocytosis is blocked by the ROCK inhibitor Y27632 or by clathrin RNA interference. In contrast, steady-state endocytosis of Kv1.2 in unstimulated cells is cholesterol dependent. Inhibition of basal ROCK signaling with Y27632 increased surface Kv1.2, an effect that persists in the presence of clathrin small interfering RNA and that is not additive to the increase in surface channel levels elicited by the cholesterol sequestering drug filipin. Temperature block experiments show that ROCK affects cholesterol-dependent trafficking by modulating the recycling of endocytosed channel back to the plasma membrane. Both receptor-stimulated and steady-state Kv1.2 trafficking modulated by RhoA/ROCK required the activation of dynamin as well as the ROCK effector Lim-kinase, indicating a key role for actin remodeling in RhoA-dependent Kv1.2 regulation.
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Affiliation(s)
- Lee Stirling
- Department of Pharmacology, College of Medicine, University of Vermont, Burlington, VT 05405, USA
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Endocytic trafficking of Rac is required for the spatial restriction of signaling in cell migration. Cell 2008; 134:135-47. [PMID: 18614017 DOI: 10.1016/j.cell.2008.05.034] [Citation(s) in RCA: 397] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2007] [Revised: 03/31/2008] [Accepted: 05/09/2008] [Indexed: 12/14/2022]
Abstract
The small GTPases, Rab5 and Rac, are essential for endocytosis and actin remodeling, respectively. Coordination of these processes is critical to achieve spatial restriction of intracellular signaling, which is essential for a variety of polarized functions. Here, we show that clathrin- and Rab5-mediated endocytosis are required for the activation of Rac induced by motogenic stimuli. Rac activation occurs on early endosomes, where the RacGEF Tiam1 is also recruited. Subsequent recycling of Rac to the plasma membrane ensures localized signaling, leading to the formation of actin-based migratory protrusions. Thus, membrane trafficking of Rac is required for the spatial resolution of Rac-dependent motogenic signals. We further demonstrate that a Rab5-to-Rac circuitry controls the morphology of motile mammalian tumor cells and primordial germinal cells during zebrafish development, suggesting that this circuitry is relevant for the regulation of migratory programs in various cells, in both in vitro settings and whole organisms.
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Linden R, Martins VR, Prado MAM, Cammarota M, Izquierdo I, Brentani RR. Physiology of the prion protein. Physiol Rev 2008; 88:673-728. [PMID: 18391177 DOI: 10.1152/physrev.00007.2007] [Citation(s) in RCA: 435] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Prion diseases are transmissible spongiform encephalopathies (TSEs), attributed to conformational conversion of the cellular prion protein (PrP(C)) into an abnormal conformer that accumulates in the brain. Understanding the pathogenesis of TSEs requires the identification of functional properties of PrP(C). Here we examine the physiological functions of PrP(C) at the systemic, cellular, and molecular level. Current data show that both the expression and the engagement of PrP(C) with a variety of ligands modulate the following: 1) functions of the nervous and immune systems, including memory and inflammatory reactions; 2) cell proliferation, differentiation, and sensitivity to programmed cell death both in the nervous and immune systems, as well as in various cell lines; 3) the activity of numerous signal transduction pathways, including cAMP/protein kinase A, mitogen-activated protein kinase, phosphatidylinositol 3-kinase/Akt pathways, as well as soluble non-receptor tyrosine kinases; and 4) trafficking of PrP(C) both laterally among distinct plasma membrane domains, and along endocytic pathways, on top of continuous, rapid recycling. A unified view of these functional properties indicates that the prion protein is a dynamic cell surface platform for the assembly of signaling modules, based on which selective interactions with many ligands and transmembrane signaling pathways translate into wide-range consequences upon both physiology and behavior.
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Affiliation(s)
- Rafael Linden
- Instituto de Biofísica da Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Arnaud F, Murcia PR, Palmarini M. Mechanisms of late restriction induced by an endogenous retrovirus. J Virol 2007; 81:11441-51. [PMID: 17699582 PMCID: PMC2045543 DOI: 10.1128/jvi.01214-07] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The host has developed during evolution a variety of "restriction factors" to fight retroviral infections. We investigated the mechanisms of a unique viral block acting at late stages of the retrovirus replication cycle. The sheep genome is colonized by several copies of endogenous retroviruses, known as enJSRVs, which are highly related to the oncogenic jaagsiekte sheep retrovirus (JSRV). enJS56A1, one of the enJSRV proviruses, can act as a restriction factor by blocking viral particles release of the exogenous JSRV. We show that in the absence of enJS56A1 expression, the JSRV Gag (the retroviral internal structural polyprotein) targets initially the pericentriolar region, in a dynein and microtubule-dependent fashion, and then colocalizes with the recycling endosomes. Indeed, by inhibiting the endocytosis and trafficking of recycling endosomes we hampered JSRV exit from the cell. Using a variety of approaches, we show that enJS56A1 and JSRV Gag interact soon after synthesis and before pericentriolar/recycling endosome targeting of the latter. The transdominant enJS56A1 induces intracellular Gag accumulation in microaggregates that colocalize with the aggresome marker GFP-250 but develop into bona fide aggresomes only when the proteasomal machinery is inhibited. The data argue that dominant-negative proteins can modify the overall structure of Gag multimers/viral particles hampering the interaction of the latter with the cellular trafficking machinery.
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Affiliation(s)
- Frederick Arnaud
- Institute of Comparative Medicine, University of Glasgow Veterinary School, 464 Bearsden Road, Glasgow, G61 1QH Scotland, United Kingdom
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Saini DK, Kalyanaraman V, Chisari M, Gautam N. A family of G protein βγ subunits translocate reversibly from the plasma membrane to endomembranes on receptor activation. J Biol Chem 2007; 282:24099-108. [PMID: 17581822 PMCID: PMC2238721 DOI: 10.1074/jbc.m701191200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The present model of G protein activation by G protein-coupled receptors exclusively localizes their activation and function to the plasma membrane (PM). Observation of the spatiotemporal response of G protein subunits in a living cell to receptor activation showed that 6 of the 12 members of the G protein gamma subunit family translocate specifically from the PM to endomembranes. The gamma subunits translocate as betagamma complexes, whereas the alpha subunit is retained on the PM. Depending on the gamma subunit, translocation occurs predominantly to the Golgi complex or the endoplasmic reticulum. The rate of translocation also varies with the gamma subunit type. Different gamma subunits, thus, confer distinct spatiotemporal properties to translocation. A striking relationship exists between the amino acid sequences of various gamma subunits and their translocation properties. gamma subunits with similar translocation properties are more closely related to each other. Consistent with this relationship, introducing residues conserved in translocating subunits into a non-translocating subunit results in a gain of function. Inhibitors of vesicle-mediated trafficking and palmitoylation suggest that translocation is diffusion-mediated and controlled by acylation similar to the shuttling of G protein subunits (Chisari, M., Saini, D. K., Kalyanaraman, V., and Gautam, N. (2007) J. Biol. Chem. 282, 24092-24098). These results suggest that the continual testing of cytosolic surfaces of cell membranes by G protein subunits facilitates an activated cell surface receptor to direct potentially active G protein betagamma subunits to intracellular membranes.
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Affiliation(s)
- Deepak Kumar Saini
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Vani Kalyanaraman
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Mariangela Chisari
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Narasimhan Gautam
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
- To whom correspondence should be addressed: Box 8054, Washington University School of Medicine, St. Louis, MO 63110. Tel.: 314-362 8568; Fax: 314-362-8571; E-mail:
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Chisari M, Saini DK, Kalyanaraman V, Gautam N. Shuttling of G protein subunits between the plasma membrane and intracellular membranes. J Biol Chem 2007; 282:24092-8. [PMID: 17576765 PMCID: PMC2238717 DOI: 10.1074/jbc.m704246200] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heterotrimeric G proteins (alphabetagamma) mediate the majority of signaling pathways in mammalian cells. It is long held that G protein function is localized to the plasma membrane. Here we examined the spatiotemporal dynamics of G protein localization using fluorescence recovery after photobleaching, fluorescence loss in photobleaching, and a photoswitchable fluorescent protein, Dronpa. Unexpectedly, G protein subunits shuttle rapidly (t1/2 < 1 min) between the plasma membrane and intracellular membranes. We show that consistent with such shuttling, G proteins constitutively reside in endomembranes. Furthermore, we show that shuttling is inhibited by 2-bromopalmitate. Thus, contrary to present thought, G proteins do not reside permanently on the plasma membrane but are constantly testing the cytoplasmic surfaces of the plasma membrane and endomembranes to maintain G protein pools in intracellular membranes to establish direct communication between receptors and endomembranes.
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Affiliation(s)
- Mariangela Chisari
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Deepak Kumar Saini
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Vani Kalyanaraman
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Narasimhan Gautam
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
- To whom correspondence should be addressed: Box 8054, Washington University School of Medicine, St. Louis, MO 63110. Tel.: 314-362-8568; Fax: 314-362-8571; E-mail:
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Barr VA, Balagopalan L, Barda-Saad M, Polishchuk R, Boukari H, Bunnell SC, Bernot KM, Toda Y, Nossal R, Samelson LE. T-Cell Antigen Receptor-Induced Signaling Complexes: Internalization Via a Cholesterol-Dependent Endocytic Pathway. Traffic 2006; 7:1143-62. [PMID: 16919152 DOI: 10.1111/j.1600-0854.2006.00464.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
T-cell antigen receptor engagement causes the rapid assembly of signaling complexes. The adapter protein SLP-76, detected as SLP-yellow fluorescent protein, initially clustered with the TCR and other proteins, then translocated medially on microtubules. As shown by total internal reflection fluorescence microscopy and the inhibition of SLP-76 movement at 16 degrees C, this movement required endocytosis. Immunoelectron microscopy showed SLP-76 staining of smooth pits and tubules. Cholesterol depletion decreased the movement of SLP-76 clusters, as did coexpression of the ubiquitin-interacting motif domain from eps15. These data are consistent with the internalization of SLP-76 via a lipid raft-dependent pathway that requires interaction of the endocytic machinery with ubiquitinylated proteins. The endocytosed SLP-76 clusters contained phosphorylated SLP-76 and phosphorylated LAT. The raft-associated, transmembrane protein LAT likely targets SLP-76 to endocytic vesicles. The endocytosis of active SLP-76 and LAT complexes suggests a possible mechanism for downregulation of signaling complexes induced by TCR activation.
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Affiliation(s)
- Valarie A Barr
- Laboratory of Cellular and Molecular Biology, Department of Health and Human Services, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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48
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Idkowiak-Baldys J, Becker KP, Kitatani K, Hannun YA. Dynamic sequestration of the recycling compartment by classical protein kinase C. J Biol Chem 2006; 281:22321-22331. [PMID: 16751194 DOI: 10.1074/jbc.m512540200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
It has been previously shown that upon sustained stimulation (30-60 min) with phorbol esters, protein kinase C (PKC) alpha and betaII become sequestered in a juxtanuclear region, the pericentrion. The activation of PKC also results in sequestration of transferrin, suggesting a role for PKC in regulating endocytosis and sequestration of recycling components. In this work we characterize the pericentrion as a PKC-dependent subset of the recycling compartment. We demonstrate that upon sustained stimulation of PKC, both protein (CD59, caveolin) and possibly also lipid (Bodipy-GM1) cargo become sequestered in a PKC-dependent manner. This sequestration displayed a strict temperature requirement and was inhibited below 32 degrees C. Treatment of cells with phorbol myristate acetate for 60 min led to the formation of a distinct membrane structure. PKC sequestration and pericentrion formation were blocked by hypertonic sucrose as well as by potassium depletion (inhibitors of clathrin-dependent endocytosis) but not by nystatin or filipin, which inhibit clathrin-independent pathways. Interestingly, it was also observed that some molecules that internalize through clathrin-independent pathways (CD59, Bodipy-GM1, caveolin) also sequestered to the pericentrion upon sustained PKC activation, suggesting that PKC acted distal to the site of internalization of endocytic cargo. Together these results suggest that PKC regulates sequestration of recycling molecules into this compartment, the pericentrion.
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Affiliation(s)
- Jolanta Idkowiak-Baldys
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kevin P Becker
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kazuyuki Kitatani
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Yusuf A Hannun
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425.
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Rotblat B, Yizhar O, Haklai R, Ashery U, Kloog Y. Ras and its signals diffuse through the cell on randomly moving nanoparticles. Cancer Res 2006; 66:1974-81. [PMID: 16488996 DOI: 10.1158/0008-5472.can-05-3791] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Spatiotemporal modulation of Ras signaling from different intracellular compartments requires mechanisms allowing Ras and its signals to navigate across cells. Here, we describe one mechanism by which clusters of palmitoylated H-Ras and N-Ras isoforms but not nonpalmitoylated K-Ras diffuse through the cytoplasm, independently of ATP, on fast, randomly moving, small cytosolic nanoparticles ("rasosomes"). Rasosomes forced to diffuse out of live cells and trapped by Ras antibody beads appear as round structures of 80- to 100-nm diameter. Association of H-Ras with rasosomes requires Ras palmitoylation and the hypervariable sequence (hvr) upstream of the palmitoylated cysteines. H-Ras hvr mutants that fail to interact with rasosomes are biologically inactive. Epidermal growth factor stimulation rapidly increases active H-Ras-GTP and phosphorylated extracellular signal-regulated kinase (ERK) on rasosomes. Similarly, rasosomes carrying H-Ras(G12V) but not H-Ras are loaded with active ERK. Thus, the rasosome represents a hitherto unknown particle that enables Ras signal information to spread rapidly across cells.
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Affiliation(s)
- Barak Rotblat
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Elangovan N, Lee YC, Tzeng WF, Chu ST. Delivery of ferric ion to mouse spermatozoa is mediated by lipocalin internalization. Biochem Biophys Res Commun 2004; 319:1096-104. [PMID: 15194480 DOI: 10.1016/j.bbrc.2004.05.091] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Indexed: 11/27/2022]
Abstract
The aim of this study was to illustrate the further process of 24p3 protein after association with epididymal spermatozoa. We have previously identified a caput-initiated 24p3 protein, which interacts with the spermatozoa surface in vitro. In the present study, we investigate another role of the 24p3 protein with spermatozoa. Mouse epididymal spermatozoa exhibit the ability to bind spontaneously with exogenous 24p3 protein, a part of which is further internalized into the spermatozoa in epididymal caput. We have now focused on this issue using freshly prepared spermatozoa from caudal region of epididymis. First, the cytosolic fractionation of spermatozoa has revealed that biotinylated 24p3 protein signal could be detected by supplying biotinylated protein under 37 degrees C incubation after 30 min at this experiment. Further, flow cytometric analysis of FITC-protein containing spermatozoa has revealed two distinct types of fluorescent spermatozoa, and microscopical experimentation with fluorescent FITC-24p3 protein has shown that the 24p3 protein did accumulate in the cytosolic portion of spermatozoa. All of these events, which showed protein uptake into the cell, demonstrated time- and temperature-dependence of endocytotic characteristics, these constituting the critical points in the process of endocytosis for spermatozoa as for other cells. Using a fluorometric method, the binding affinities of ferrous ion and ferric ion to 24p3 protein were shown to be (1.5+/-0.2)x10(6) and (3.0+/-0.4)x10(7)M(-1), respectively. We have also determined the internalization of this protein in the transition of iron into spermatozoa. We report here that spermatozoa, from the caudal epididymis, demonstrate the ability to bind with 24p3 protein and further internalize it and deliver the ferric ion to the spermatozoa via protein internalization. We suggest that the 24p3 protein plays a physiological role in spermatozoa in the context of protein-ligand complex internalization.
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