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Shi Q, Zhao R, Chen L, Liu T, Di T, Zhang C, Zhang Z, Wang F, Han Z, Sun J, Liu S. Newcastle disease virus activates diverse signaling pathways via Src to facilitate virus entry into host macrophages. J Virol 2024; 98:e0191523. [PMID: 38334327 PMCID: PMC10949470 DOI: 10.1128/jvi.01915-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 12/27/2023] [Indexed: 02/10/2024] Open
Abstract
As an intrinsic cellular mechanism responsible for the internalization of extracellular ligands and membrane components, caveolae-mediated endocytosis (CavME) is also exploited by certain pathogens for endocytic entry [e.g., Newcastle disease virus (NDV) of paramyxovirus]. However, the molecular mechanisms of NDV-induced CavME remain poorly understood. Herein, we demonstrate that sialic acid-containing gangliosides, rather than glycoproteins, were utilized by NDV as receptors to initiate the endocytic entry of NDV into HD11 cells. The binding of NDV to gangliosides induced the activation of a non-receptor tyrosine kinase, Src, leading to the phosphorylation of caveolin-1 (Cav1) and dynamin-2 (Dyn2), which contributed to the endocytic entry of NDV. Moreover, an inoculation of cells with NDV-induced actin cytoskeletal rearrangement through Src to facilitate NDV entry via endocytosis and direct fusion with the plasma membrane. Subsequently, unique members of the Rho GTPases family, RhoA and Cdc42, were activated by NDV in a Src-dependent manner. Further analyses revealed that RhoA and Cdc42 regulated the activities of specific effectors, cofilin and myosin regulatory light chain 2, responsible for actin cytoskeleton rearrangement, through diverse intracellular signaling cascades. Taken together, our results suggest that an inoculation of NDV-induced Src-mediated cellular activation by binding to ganglioside receptors. This process orchestrated NDV endocytic entry by modulating the activities of caveolae-associated Cav1 and Dyn2, as well as specific Rho GTPases and downstream effectors. IMPORTANCE In general, it is known that the paramyxovirus gains access to host cells through direct penetration at the plasma membrane; however, emerging evidence suggests more complex entry mechanisms for paramyxoviruses. The endocytic entry of Newcastle disease virus (NDV), a representative member of the paramyxovirus family, into multiple types of cells has been recently reported. Herein, we demonstrate the binding of NDV to induce ganglioside-activated Src signaling, which is responsible for the endocytic entry of NDV through caveolae-mediated endocytosis. This process involved Src-dependent activation of the caveolae-associated Cav1 and Dyn2, as well as specific Rho GTPase and downstream effectors, thereby orchestrating the endocytic entry process of NDV. Our findings uncover a novel molecular mechanism of endocytic entry of NDV into host cells and provide novel insight into paramyxovirus mechanisms of entry.
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Affiliation(s)
- Qiankai Shi
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ran Zhao
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Linna Chen
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Tianyi Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Tao Di
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chunwei Zhang
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhiying Zhang
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Fangfang Wang
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zongxi Han
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Junfeng Sun
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Shengwang Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
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Majumder R, Karmakar S, Mishra S, Mallick AB, Das Mukhopadhyay C. Functionalized Carbon Nano-Onions as a Smart Drug Delivery System for the Poorly Soluble Drug Carmustine for the Management of Glioblastoma. ACS APPLIED BIO MATERIALS 2024; 7:154-167. [PMID: 38088856 DOI: 10.1021/acsabm.3c00688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Abstract
The drug delivery system for transporting anticancer agents to targeted tissues in the body is a challenging issue. In search of a suitable biocompatible carrier having controlled and sustained drug release properties of poorly soluble drugs, carbon nano-onions (CNOs) were loaded with an anticancer drug, bis-chloroethyl nitrosourea (BCNU/carmustine). CNOs being autofluorescent, drug-loaded functionalized CNOs (f-CNO-BCNU) can be detected in vivo. Transmission electron microscopy (TEM) and differential light scattering (DLS) techniques were used to analyze the sizes of these f-CNOs. The molecular study revealed that the f-CNO-BCNU readily and noncovalently binds with the folate receptors present on the cancer cell surface in excess. Computer modeling and molecular dynamics simulation followed by binding free energy calculation shows f-CNOs have -29.9 kcal/mol binding free energy, and it noncovalently binds the receptor FRα using loop dynamics of three essential loops present in the protein along with polar stabilization interactions provided by Asp55 and Glu86 residues present in the active site. The f-CNO effectively decreased cancer cell viability with a low IC50 value (the concentration that led to 50% killing of the cells). The cell-based Franz diffusion assay was performed to study the drug release profile. The f-CNO-BCNUs also decreased the mitochondrial membrane potential of U87 cells, increased reactive oxygen species release, and caused a loss of mitochondrial membrane integrity. The f-CNOs also increased the percentage of apoptotic cells observed by the Annexin V assay. Based on observed results, it can be concluded that the f-CNO-BCNU efficiently targets the cancer cells, enhances the bioavailability of carmustine, and can be used as a smart chemotherapeutic agent. This strategy offers better patient compliance and greater bioavailability of the drug.
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Affiliation(s)
- Rabindranath Majumder
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal 711103, India
| | - Soumyajit Karmakar
- Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Sabyashachi Mishra
- Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Amitava Basu Mallick
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal 711103, India
| | - Chitrangada Das Mukhopadhyay
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, West Bengal 711103, India
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Lee K, Davis B, Wang X, Mirg S, Wen C, Abune L, Peterson BE, Han L, Chen H, Wang H, Szczesny SE, Lei Y, Kothapalli SR, Wang Y. Nanoparticle-Decorated Biomimetic Extracellular Matrix for Cell Nanoencapsulation and Regulation. Angew Chem Int Ed Engl 2023; 62:e202306583. [PMID: 37277318 PMCID: PMC10526972 DOI: 10.1002/anie.202306583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/07/2023]
Abstract
Cell encapsulation has been studied for various applications ranging from cell transplantation to biological production. However, current encapsulation technologies focus on cell protection rather than cell regulation that is essential to most if not all cell-based applications. Here we report a method for cell nanoencapsulation and regulation using an ultrathin biomimetic extracellular matrix as a cell nanocapsule to carry nanoparticles (CN2 ). This method allows high-capacity nanoparticle retention at the vicinity of cell surfaces. The encapsulated cells maintain high viability and normal metabolism. When gold nanoparticles (AuNPs) are used as a model to decorate the nanocapsule, light irradiation transiently increases the temperature, leading to the activation of the heat shock protein 70 (HSP70) promoter and the regulation of reporter gene expression. As the biomimetic nanocapsule can be decorated with any or multiple NPs, CN2 is a promising platform for advancing cell-based applications.
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Affiliation(s)
- Kyungsene Lee
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Brandon Davis
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Xuelin Wang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Shubham Mirg
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Connie Wen
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Lidya Abune
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Benjamin E Peterson
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Li Han
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Haoyang Chen
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Hongjun Wang
- Department of Biomedical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Spencer E Szczesny
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yuguo Lei
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sri-Rajasekhar Kothapalli
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
| | - Yong Wang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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Visca H, DuPont M, Moshnikova A, Crawford T, Engelman DM, Andreev OA, Reshetnyak YK. pHLIP Peptides Target Acidity in Activated Macrophages. Mol Imaging Biol 2022; 24:874-885. [PMID: 35604527 PMCID: PMC9681937 DOI: 10.1007/s11307-022-01737-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/19/2022] [Accepted: 04/27/2022] [Indexed: 12/29/2022]
Abstract
PURPOSE Acidity can be a useful alternative biomarker for the targeting of metabolically active cells in certain diseased tissues, as in acute inflammation or aggressive tumors. We investigated the targeting of activated macrophages by pH low insertion peptides (pHLIPs), an established technology for targeting cell-surface acidity. PROCEDURES The uptake of fluorescent pHLIPs by activated macrophages was studied in cell cultures, in a mouse model of lung inflammation, and in a mouse tumor model. Fluorescence microscopy, whole-body and organ imaging, immunohistochemistry, and FACS analysis were employed. RESULTS We find that cultured, activated macrophages readily internalize pHLIPs. The uptake is higher in glycolytic macrophages activated by LPS and INF-γ compared to macrophages activated by IL-4/IL-13. Fluorescent pHLIPs target LPS-induced lung inflammation in mice. In addition to marking cancer cells within the tumor microenvironment, fluorescent pHLIPs target CD45+, CD11b+, F4/80+, and CD206+ tumor-associated macrophages with no significant targeting of other immune cells. Also, fluorescent pHLIPs target CD206-positive cells found in the inguinal lymph nodes of animals inoculated with breast cancer cells in mammary fat pads. CONCLUSIONS pHLIP peptides sense low cell surface pH, which triggers their insertion into the cell membrane. Unlike cancerous cells, activated macrophages do not retain inserted pHLIPs on their surfaces, instead their highly active membrane recycling moves the pHLIPs into endosomes. Targeting activated macrophages in diseased tissues may enable clinical visualization and therapeutic opportunities.
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Affiliation(s)
- Hannah Visca
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Michael DuPont
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Anna Moshnikova
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Troy Crawford
- Physics Department, University of Rhode Island, Kingston, RI, USA
| | - Donald M Engelman
- Department of Molecular Biophysics and Biochemistry, Yale, New Haven, CT, USA
| | - Oleg A Andreev
- Physics Department, University of Rhode Island, Kingston, RI, USA
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Specific Binding and Endocytosis of Liposomes to HEK293T Cells via Myrisoylated Pre-S1 Peptide Bound to Sodium Taurocholate Cotransporting Polypeptide. Vaccines (Basel) 2022; 10:vaccines10122050. [PMID: 36560460 PMCID: PMC9782868 DOI: 10.3390/vaccines10122050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 11/22/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
(1) Background: Sodium taurocholate cotransporting polypeptide (NTCP) functions as a key receptor for the hepatitis B virus (HBV) infection. Analyzing HBV and NTCP interaction is an important issue not only for basic research but also for the development of anti-HBV therapeutics. We developed here a novel model system to analyze the interaction of NTCP with liposomes instead of HBV. (2) Methods: Liposomal binding and endocytosis through NTCP in HEK293T cells were achieved by serial treatments of HEL293T cells transiently expressing NTCP-green fluorescence protein (GFP) fusion protein with a synthetic biotinylated pre-S1 peptide (Myr47-Bio) and streptavidin (SA) complex (i.e., Myr47-Bio+SA) followed by biotinylated liposomes. By this procedure, binding of [biotinylated liposomes]-[Myr47-Bio+SA]-[NTCP-GFP] was formed. (3) Results: Using this model system, we found that liposomal binding to NTCP on the cell surface via Myr47-Bio+SA was far more efficient than that to scavenger receptor class B type 1 (SR-B1). Furthermore, liposomes bound to cell surface NTCP via Myr47-Bio+SA were endocytosed into cells after cells were cultured at 37 °C. However, this endocytosis was suppressed by 4 °C or cytochalasin B treatment. (4) Conclusions: This model system will be useful for not only analyzing HBV entry mechanisms but also screening substances to prevent HBV infection.
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Kinetics of Pectin Biopolymer Facial Erosion Characterized by Fluorescent Tracer Microfluidics. Polymers (Basel) 2022; 14:polym14183911. [PMID: 36146055 PMCID: PMC9501333 DOI: 10.3390/polym14183911] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 08/29/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
Pectin is a plant-derived heteropolysaccharide that has been implicated in drug development, tissue engineering, and visceral organ repair. Pectin demonstrates remarkable biostability in a variety of physiologic environments but is biodegradable in water. To understand the dynamics of pectin biodegradation in basic environments, we developed a microfluidics system that facilitated the quantitative comparison of pectin films exposed to facial erosion. Pectin biodegradation was assessed using fluorescein tracer embedded in pectin, trypan blue quenching of released fluorescence, and highly sensitive microfluorimetry. The microfluidic perfusate, delivered through 6 um-pore synthetic membrane interface, demonstrated nonlinear erosion of the pectin film; 75% of tracer was released in 28 h. The microfluidics system was used to identify potential modifiers of pectin erosion. The polyphenolic compound tannic acid, loaded into citrus pectin films, demonstrated a dose-dependent decrease in pectin erosion. Tannic acid had no detectable impact on the physical properties of citrus pectin including adhesivity and cohesion. In contrast, tannic acid weakened the burst strength and cohesion of pectins derived from soy bean and potato sources. We conclude that facial erosion may explain the biostability of citrus pectin on visceral organ surfaces as well as provide a useful method for identifying modifiers of citrus pectin biodegradation.
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Fernández-Delgado M, Sendra L, Herrero MJ, Olivera-Pasquini GG, Batista-Duharte A, Aliño SF. Study of Oligonucleotides Access and Distribution in Human Peripheral Blood Mononuclear Cells. Int J Mol Sci 2022; 23:5839. [PMID: 35628649 PMCID: PMC9143973 DOI: 10.3390/ijms23105839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 12/31/2022] Open
Abstract
Therapeutic oligonucleotides have achieved great clinical interest since their approval as drug agents by regulatory agencies but their access and distribution in blood cells are not completely known. We evaluated by flow cytometry the ability of short fluorescent scramble oligonucleotides (ON*) to access human peripheral blood mononuclear cells (PBMC) after incubating with ON* during 1 h and 7 days of culture follow-up 'in vitro'. Blood samples were treated with chemically modified oligonucleotides (phosphorothioate backbone and 2' O-Me ends) to resist nuclease digestion under culture conditions. The ON* internalization was determined after discarding the membrane-associated fluorescence by trypan blue quenching. Whereas the oligonucleotide accessed neutrophils and monocytes rapidly, achieving their maximum in 1 h and 24 h, respectively, lymphocytes required 7 days to achieve the maximum (80% of cells) transfection. The ON*ability to access lymphocyte types (T, B, and NK) and T cell subtypes (CD4+, CD8+, and CD4-CD8-) were similar, with T cells being more accessible. Regulatory CD4+ and CD8+ T cells were classified in low and high Foxp3 expressers, whose expression proved not to alter the ON* internalization during the first hour, achieving 53% of CD4+Foxp3+ and 40% of CD8+Foxp3+ cells. Our results contribute to understanding and improving the management of therapeutic ONs.
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Affiliation(s)
- Manuel Fernández-Delgado
- Service of Hematology and Hemotherapy, Hospital General Universitario de Castellón, 12004 Castelló de la Plana, Spain;
| | - Luis Sendra
- Farmacogenetics and Gene Therapy Group, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell, 106, 46026 Valencia, Spain; (M.J.H.); (G.G.O.-P.); (S.F.A.)
- Gene Therapy and Pharmacogenomics Group, Department of Pharmacology, Faculty of Medicine, University of Valencia, Av. Blasco Ibáñez 15, 46010 Valencia, Spain
| | - María José Herrero
- Farmacogenetics and Gene Therapy Group, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell, 106, 46026 Valencia, Spain; (M.J.H.); (G.G.O.-P.); (S.F.A.)
- Gene Therapy and Pharmacogenomics Group, Department of Pharmacology, Faculty of Medicine, University of Valencia, Av. Blasco Ibáñez 15, 46010 Valencia, Spain
| | - Gladys G. Olivera-Pasquini
- Farmacogenetics and Gene Therapy Group, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell, 106, 46026 Valencia, Spain; (M.J.H.); (G.G.O.-P.); (S.F.A.)
| | - Alexander Batista-Duharte
- GC01 Immunology and Allergy Group, Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Av. Menéndez Pidal, s/n, 14004 Córdoba, Spain;
- Laboratório de Imunología Clínica, Dpto Analises Clinicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista (UNESP), Rod. Araraquara-Jaú—Km 1, Campus Ville, 14800 Araraquara, Sao Paulo, Brazil
| | - Salvador F. Aliño
- Farmacogenetics and Gene Therapy Group, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell, 106, 46026 Valencia, Spain; (M.J.H.); (G.G.O.-P.); (S.F.A.)
- Gene Therapy and Pharmacogenomics Group, Department of Pharmacology, Faculty of Medicine, University of Valencia, Av. Blasco Ibáñez 15, 46010 Valencia, Spain
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Khandelwal R, Sharma AK, Biswa BB, Sharma Y. Extracellular Secretagogin is internalized into the cells through endocytosis. FEBS J 2021; 289:3183-3204. [PMID: 34967502 DOI: 10.1111/febs.16338] [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: 11/25/2021] [Accepted: 11/29/2021] [Indexed: 11/29/2022]
Abstract
Secretagogin (SCGN) is a calcium-sensor protein with a regulatory role in glucose metabolism and the secretion of several peptide hormones. Many, but not all, functions of SCGN can be explained by its intracellular manifestation. Despite early data on SCGN secretion, the secretory mechanism, biological fate, physiological implications, and trans-cellular signaling of extracellular SCGN remain unknown. We here report that extracellular SCGN is readily internalized into the C2C12 cells in an energy-dependent manner. Using endocytosis inhibitors, we demonstrate that SCGN internalizes via clathrin-mediated endocytosis, following which, SCGN localizes largely in the cytosol. Exogenous SCGN treatment induces a global proteomic reprogramming in C2C12 cells. Gene ontology search suggests that SCGN-induced proteomic reprogramming favors protein synthesis and cellular growth. We thus validated the cell proliferative action of SCGN using C2C12, HepG2, and NIH-3T3 cell lines. Based on the data, we propose that circulatory SCGN is internalized into the target cells and modulates the expression of cell growth-related proteins. The work suggests that extracellular SCGN is a functional protein, which communicates with specific cell types and directly modulates cell proliferation.
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Affiliation(s)
- Radhika Khandelwal
- CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500 007, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, India
| | - Anand Kumar Sharma
- CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500 007, India
| | - Bhim B Biswa
- CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500 007, India
| | - Yogendra Sharma
- CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500 007, India.,Academy of Scientific and Innovative Research (AcSIR), New Delhi, India.,Indian Institute of Science Education and Research (IISER), Berhampur, Odisha, 760010, India
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Georgieva M, Heinonen T, Vitale A, Hargraves S, Causevic S, Pillonel T, Eberl L, Widmann C, Jacquier N. Bacterial surface properties influence the activity of the TAT-RasGAP 317-326 antimicrobial peptide. iScience 2021; 24:102923. [PMID: 34430812 PMCID: PMC8365389 DOI: 10.1016/j.isci.2021.102923] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/05/2021] [Accepted: 07/27/2021] [Indexed: 12/13/2022] Open
Abstract
Antibiotic resistance is an increasing threat for public health, underscoring the need for new antibacterial agents. Antimicrobial peptides (AMPs) represent an alternative to classical antibiotics. TAT-RasGAP317-326 is a recently described AMP effective against a broad range of bacteria, but little is known about the conditions that may influence its activity. Using RNA-sequencing and screening of mutant libraries, we show that Escherichia coli and Pseudomonas aeruginosa respond to TAT-RasGAP317-326 by regulating metabolic and stress response pathways, possibly implicating two-component systems. Our results also indicate that bacterial surface properties, in particular integrity of the lipopolysaccharide layer, influence peptide binding and entry. Finally, we found differences between bacterial species with respect to their rate of resistance emergence against this peptide. Our findings provide the basis for future investigation on the mode of action of TAT-RasGAP317-326, which may help developing antimicrobial treatments based on this peptide.
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Affiliation(s)
- Maria Georgieva
- Department of Biomedical Sciences, University of Lausanne, Lausanne 1005, Switzerland
| | - Tytti Heinonen
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Alessandra Vitale
- Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Simone Hargraves
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Senka Causevic
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Trestan Pillonel
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
| | - Leo Eberl
- Department of Plant and Microbial Biology, University of Zurich, Zurich 8008, Switzerland
| | - Christian Widmann
- Department of Biomedical Sciences, University of Lausanne, Lausanne 1005, Switzerland
- Corresponding author
| | - Nicolas Jacquier
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne 1011, Switzerland
- Corresponding author
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Cellular Autofluorescence in Mouse Embryonic Fibroblasts Interferes with Antigen Detection Using Flow Cytometry. J Fluoresc 2021; 31:873-879. [PMID: 33772682 DOI: 10.1007/s10895-021-02724-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/17/2021] [Indexed: 10/21/2022]
Abstract
Immunostaining is one of the advantageous methods for the qualitative analysis of cellular markers of interest. Immuno-stained cells are typically analyzed by fluorescence microscopy or flow cytometry. Flow cytometry has the advantage of being able to process large numbers of cells in a short time thus enhancing its quantitative capacity. The staining protocol typically includes fixation of cells followed by permeabilization, blocking procedures to reduce non-specific binding of the label, and staining with specific antibodies labeled directly or indirectly with fluorescence-tags. Important controls include staining with a relevant non-immune antibody to identify any non-specific imminent globally binding and measurements in the absence of any fluorescent tag to detect non-specific sources of fluorescence. The most common source of non-specific fluorescence is caused by autofluorescence of naturally occurring chemicals within the cells of interest. In this study, we found high levels of cellular autofluorescence in mouse embryonic fibroblasts, at levels that interfered with the detection of a number of cellular antigens using common fluorophores. This autofluorescence was detected in three of the four fluorescence channels restricting useful analysis to only one channel (red) on the instrument. The study highlights an important limitation to immunostaining techniques and reinforces the need for the use of a thorough set of controls to ensure specificity of quantitative analysis.
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Bulut O, Oktem HA, Yilmaz MD. A highly substituted and fluorescent aromatic-fused imidazole derivative that shows enhanced antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). JOURNAL OF HAZARDOUS MATERIALS 2020; 399:122902. [PMID: 32512278 DOI: 10.1016/j.jhazmat.2020.122902] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/23/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
A novel highly substituted and fluorescent aromatic-fused imidazole derivative has been synthesized by rational design. This novel fluorescent material acts as an alternative antibacterial agent against Gram positive bacteria strains. It shows superior antibacterial activity (with MIC value of 8 μg/mL) against methicillin-resistant Staphylococcus aureus (MRSA) when compared with standard antibiotic drugs Ampicillin (with MIC value of 128 μg/mL) and Kanamycin (with MIC value of >512 μg/mL). The interaction of this novel compound with the bacterial cell and genomic DNA has also been studied to elucidate antibacterial mode of action. Fluorescence spectroscopy and microscopy studies have proved the intracellular uptake of this special compound. Likewise, UV-vis and fluorescence spectroscopy studies have revealed a significant decrease in the absorption and emission bands of the compound upon its interaction with plasmid and genomic DNA, which is likely due to its DNA intercalation property. Furthermore, these findings have been supported by gel electrophoresis of genomic DNA of S. aureus cells treated with the compound. The results indicate that this novel compound exerts its antibacterial activity by causing DNA damage, suggesting the potential utility of fluorescent probes for real-time diagnosis and treatment of bacterial infections.
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Affiliation(s)
- Onur Bulut
- Department of Molecular Biology and Genetics, Faculty of Agriculture and Natural Sciences, Konya Food and Agriculture University, 42080 Konya, Turkey; Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey; Research and Development Center for Diagnostic Kits (KIT-ARGEM), Konya Food and Agriculture University, 42080 Konya, Turkey
| | - Huseyin Avni Oktem
- Department of Biological Sciences, Middle East Technical University, 06800 Ankara, Turkey; Nanobiz Technology Inc., Gallium Block No: 27 / 218, METU Technopolis, Ankara, Turkey
| | - M Deniz Yilmaz
- Research and Development Center for Diagnostic Kits (KIT-ARGEM), Konya Food and Agriculture University, 42080 Konya, Turkey; Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, 42080 Konya, Turkey.
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12
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Ackun-Farmmer MA, Alatise KL, Cross G, Benoit DSW. Ligand Density Controls C-Type Lectin-Like Molecule-1 Receptor-Specific Uptake of Polymer Nanoparticles. ADVANCED BIOSYSTEMS 2020; 4:e2000172. [PMID: 33073549 PMCID: PMC7959326 DOI: 10.1002/adbi.202000172] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/01/2020] [Indexed: 01/13/2023]
Abstract
The newest generation of drug delivery systems (DDSs) exploits ligands to mediate specific targeting of cells and/or tissues. However, studies investigating the link between ligand density and nanoparticle (NP) uptake are limited to a small number of ligand-receptor systems. C-type lectin-like molecule-1 (CLL1) is uniquely expressed on myeloid cells, which enables the development of receptors specifically targeting treat various diseases. This study aims to investigate how NPs with different CLL1 targeting peptide density impact cellular uptake. To this end, poly(styrene-alt-maleic anhydride)-b-poly(styrene) NPs are functionalized with cyclized CLL1 binding peptides (cCBP) ranging from 240 ± 12 to 31 000 ± 940 peptides per NP. Unexpectedly, the percentage of cells with internalized NPs is decreased for all cCBP-NP designs regardless of ligand density compared to unmodified NPs. Internalization through CLL1 receptor-mediated processes is further investigated without confounding the effects of NP size and surface charge. Interestingly, high density cCBP-NPs (>7000 cCBP per NP) uptake is dominated by CLL1 receptor-mediated processes while low density cCBP-NPs (≈200 cCBP per NP) and untargeted NP occurred through non-specific clathrin and caveolin-mediated endocytosis. Altogether, these studies show that ligand density and uptake mechanism should be carefully investigated for specific ligand-receptor systems for the design of targeted DDSs to achieve effective drug delivery.
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Affiliation(s)
- Marian A Ackun-Farmmer
- University of Rochester, Department of Biomedical Engineering, Rochester, NY, USA
- University of Rochester Medical Center, Department of Orthopaedics and Center for Musculoskeletal Research, Rochester, NY, USA
| | - Kharimat L Alatise
- University of Rochester, Department of Biomedical Engineering, Rochester, NY, USA
| | - Griffin Cross
- Washington University in St. Louis, Biomedical/Medical Engineering, St. Louis, MO, USA
| | - Danielle S W Benoit
- University of Rochester, Department of Biomedical Engineering, Rochester, NY, USA
- University of Rochester Medical Center, Department of Orthopaedics and Center for Musculoskeletal Research, Rochester, NY, USA
- University of Rochester, Materials Science Program, Rochester, NY, USA
- University of Rochester, Department of Chemical Engineering, Rochester, NY, USA
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13
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Li SS, Saleh M, Xiang RF, Ogbomo H, Stack D, Huston SH, Mody CH. Natural killer cells kill Burkholderia cepacia complex via a contact-dependent and cytolytic mechanism. Int Immunol 2020; 31:385-396. [PMID: 31051036 DOI: 10.1093/intimm/dxz016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 04/19/2019] [Indexed: 12/15/2022] Open
Abstract
Burkholderia cepacia complex (Bcc), which includes B. cenocepacia and B. multivorans, pose a life-threatening risk to patients with cystic fibrosis. Eradication of Bcc is difficult due to the high level of intrinsic resistance to antibiotics, and failure of many innate immune cells to control the infection. Because of the pathogenesis of Bcc infections, we wondered if a novel mechanism of microbial host defense involving direct antibacterial activity by natural killer (NK) cells might play a role in the control of Bcc. We demonstrate that NK cells bound Burkholderia, resulting in Src family kinase activation as measured by protein tyrosine phosphorylation, granule release of effector proteins such as perforin and contact-dependent killing of the bacteria. These studies provide a means by which NK cells could play a role in host defense against Bcc infection.
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Affiliation(s)
- Shu Shun Li
- Department of Microbiology, Immunology and Infectious Diseases, Alberta, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Alberta, Canada
| | - Marwah Saleh
- Department of Microbiology, Immunology and Infectious Diseases, Alberta, Canada
| | - Richard F Xiang
- Department of Microbiology, Immunology and Infectious Diseases, Alberta, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Alberta, Canada
| | - Henry Ogbomo
- Department of Microbiology, Immunology and Infectious Diseases, Alberta, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Alberta, Canada
| | - Danuta Stack
- Department of Microbiology, Immunology and Infectious Diseases, Alberta, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Alberta, Canada
| | - Shaunna H Huston
- The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Alberta, Canada
| | - Christopher H Mody
- Department of Microbiology, Immunology and Infectious Diseases, Alberta, Canada.,The Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Alberta, Canada.,Department of Medicine, University of Calgary, Calgary, Alberta, Canada
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14
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Mukherjee K, Khatua B, Mandal C. Sialic Acid-Siglec-E Interactions During Pseudomonas aeruginosa Infection of Macrophages Interferes With Phagosome Maturation by Altering Intracellular Calcium Concentrations. Front Immunol 2020; 11:332. [PMID: 32184783 PMCID: PMC7059019 DOI: 10.3389/fimmu.2020.00332] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 02/10/2020] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa (PA) is commonly associated with nosocomial and chronic infections of lungs. We have earlier demonstrated that an acidic sugar, sialic acid, is present in PA which is recognized and bound by sialic acid binding immunoglobulin type lectins (siglecs) expressed on neutrophils. Here, we have tried to gain a detailed insight into the immunosuppressive role of sialic acid-siglec interactions in macrophage-mediated clearance of sialylated PA (PA+Sia). We have demonstrated that PA+Sia shows enhanced binding (~1.5-fold) to macrophages due to additional interactions between sialic acids and siglec-E and exhibited more phagocytosis. However, internalization of PA+Sia is associated with a reduction in respiratory burst and increase in anti-inflammatory cytokines secretion which is reversed upon desialylation of the bacteria. Phagocytosis of PA+Sia is also associated with reduced intracellular calcium ion concentrations and altered calcium-dependent signaling which negatively affects phagosome maturation. Consequently, although more PA+Sia was localized in early phagosomes (Rab5 compartment), only fewer bacteria reach into the late phagosomal compartment (Rab7). Possibly, this leads to reduced phagosome lysosome fusion where reduced numbers of PA+Sia are trafficked into lysosomes, compared to PA−Sia. Thus, internalized PA+Sia remain viable and replicates intracellularly in macrophages. We have also demonstrated that such siglec-E-sialic acid interaction recruited SHP-1/SHP-2 phosphatases which modulate MAPK and NF-κB signaling pathways. Disrupting sialic acid-siglec-E interaction by silencing siglec-E in macrophages results in improved bactericidal response against PA+Sia characterized by robust respiratory burst, enhanced intracellular calcium levels and nuclear translocation of p65 component of NF-κB complex leading to increased pro-inflammatory cytokine secretion. Taken together, we have identified that sialic acid-siglec-E interactions is another pathway utilized by PA in order to suppress macrophage antimicrobial responses and inhibit phagosome maturation, thereby persisting as an intracellular pathogen in macrophages.
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Affiliation(s)
- Kaustuv Mukherjee
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Biswajit Khatua
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Chitra Mandal
- Cancer Biology and Inflammatory Disorder Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
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15
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Gomez I, Ward B, Souilhol C, Recarti C, Ariaans M, Johnston J, Burnett A, Mahmoud M, Luong LA, West L, Long M, Parry S, Woods R, Hulston C, Benedikter B, Niespolo C, Bazaz R, Francis S, Kiss-Toth E, van Zandvoort M, Schober A, Hellewell P, Evans PC, Ridger V. Neutrophil microvesicles drive atherosclerosis by delivering miR-155 to atheroprone endothelium. Nat Commun 2020; 11:214. [PMID: 31924781 PMCID: PMC6954269 DOI: 10.1038/s41467-019-14043-y] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 12/11/2019] [Indexed: 12/18/2022] Open
Abstract
Neutrophils are implicated in the pathogenesis of atherosclerosis but are seldom detected in atherosclerotic plaques. We investigated whether neutrophil-derived microvesicles may influence arterial pathophysiology. Here we report that levels of circulating neutrophil microvesicles are enhanced by exposure to a high fat diet, a known risk factor for atherosclerosis. Neutrophil microvesicles accumulate at disease-prone regions of arteries exposed to disturbed flow patterns, and promote vascular inflammation and atherosclerosis in a murine model. Using cultured endothelial cells exposed to disturbed flow, we demonstrate that neutrophil microvesicles promote inflammatory gene expression by delivering miR-155, enhancing NF-κB activation. Similarly, neutrophil microvesicles increase miR-155 and enhance NF-κB at disease-prone sites of disturbed flow in vivo. Enhancement of atherosclerotic plaque formation and increase in macrophage content by neutrophil microvesicles is dependent on miR-155. We conclude that neutrophils contribute to vascular inflammation and atherogenesis through delivery of microvesicles carrying miR-155 to disease-prone regions.
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Affiliation(s)
- Ingrid Gomez
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Ben Ward
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
| | - Celine Souilhol
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
| | - Chiara Recarti
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- Department of Molecular Cell Biology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Mark Ariaans
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Jessica Johnston
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Amanda Burnett
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Marwa Mahmoud
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- Cardiovascular Mechanobiology and Nanomedicine, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Le Anh Luong
- William Harvey Research Institute, Queen Mary University, London, UK
| | - Laura West
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Merete Long
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Sion Parry
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Rachel Woods
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Carl Hulston
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Birke Benedikter
- Department of Medical Microbiology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, Maastricht, The Netherlands
| | - Chiara Niespolo
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Rohit Bazaz
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Sheila Francis
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Endre Kiss-Toth
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Marc van Zandvoort
- Department of Molecular Cell Biology, CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Andreas Schober
- Experimental Vascular Medicine, Ludwig-Maximilian University of Munich, Munich, Germany
| | - Paul Hellewell
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- College of Health and Life Sciences, Brunel University, London, UK
| | - Paul C Evans
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, UK
- Bateson Institute, University of Sheffield, Sheffield, UK
| | - Victoria Ridger
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK.
- INSIGNEO Institute for In Silico Medicine, University of Sheffield, Sheffield, UK.
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16
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Yang Y, Xia M, Zhang S, Zhang X. Cell-penetrating peptide-modified quantum dots as a ratiometric nanobiosensor for the simultaneous sensing and imaging of lysosomes and extracellular pH. Chem Commun (Camb) 2020; 56:145-148. [DOI: 10.1039/c9cc07596h] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A ratiometric QD-peptide nanobiosensor is developed for the simultaneous sensing and imaging of lysosomes and extracellular pH.
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Affiliation(s)
- Yan Yang
- Department of Chemistry
- Tsinghua University
- Beijing
- China
| | - Mengchan Xia
- Department of Chemistry
- Tsinghua University
- Beijing
- China
| | - Sichun Zhang
- Department of Chemistry
- Tsinghua University
- Beijing
- China
| | - Xinrong Zhang
- Department of Chemistry
- Tsinghua University
- Beijing
- China
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17
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Kumar GA, Karmakar J, Mandal C, Chattopadhyay A. Leishmania donovani Internalizes into Host Cells via Caveolin-mediated Endocytosis. Sci Rep 2019; 9:12636. [PMID: 31477757 PMCID: PMC6718660 DOI: 10.1038/s41598-019-49007-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/19/2019] [Indexed: 02/08/2023] Open
Abstract
Leishmania donovani is an intracellular protozoan parasite that causes visceral leishmaniasis, a major cause of mortality and morbidity worldwide. The host plasma membrane serves as the portal of entry for Leishmania to gain access to the cellular interior. Although several host cell membrane receptors have been shown to be involved in the entry of Leishmania donovani into host cells, the endocytic pathway involved in the internalization of the parasite is not known. In this work, we explored the endocytic pathway involved in the entry of Leishmania donovani into host macrophages, utilizing specific inhibitors against two major pathways of internalization, i.e., clathrin- and caveolin-mediated endocytosis. We show that pitstop 2, an inhibitor for clathrin-mediated endocytosis, does not affect the entry of Leishmania donovani promastigotes into host macrophages. Interestingly, a significant reduction in internalization was observed upon treatment with genistein, an inhibitor for caveolin-mediated endocytosis. These results are supported by a similar trend in intracellular amastigote load within host macrophages. These results suggest that Leishmania donovani utilizes caveolin-mediated endocytosis to internalize into host cells. Our results provide novel insight into the mechanism of phagocytosis of Leishmania donovani into host cells and assume relevance in the development of novel therapeutics against leishmanial infection.
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Affiliation(s)
- G Aditya Kumar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India
| | - Joyshree Karmakar
- CSIR-Indian Institute of Chemical Biology, Raja S.C. Mullick Road, Kolkata, 700 032, India
| | - Chitra Mandal
- CSIR-Indian Institute of Chemical Biology, Raja S.C. Mullick Road, Kolkata, 700 032, India.
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18
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Guo X, Carter MCD, Appadoo V, Lynn DM. Tunable and Selective Degradation of Amine-Reactive Multilayers in Acidic Media. Biomacromolecules 2019; 20:3464-3474. [DOI: 10.1021/acs.biomac.9b00756] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Xuanrong Guo
- Department of Chemical and Biological Engineering, University of Wisconsin—Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
| | - Matthew C. D. Carter
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Visham Appadoo
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - David M. Lynn
- Department of Chemical and Biological Engineering, University of Wisconsin—Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, United States
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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19
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Abay A, Simionato G, Chachanidze R, Bogdanova A, Hertz L, Bianchi P, van den Akker E, von Lindern M, Leonetti M, Minetti G, Wagner C, Kaestner L. Glutaraldehyde - A Subtle Tool in the Investigation of Healthy and Pathologic Red Blood Cells. Front Physiol 2019; 10:514. [PMID: 31139090 PMCID: PMC6527840 DOI: 10.3389/fphys.2019.00514] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/11/2019] [Indexed: 01/03/2023] Open
Abstract
Glutaraldehyde is a well-known substance used in biomedical research to fix cells. Since hemolytic anemias are often associated with red blood cell shape changes deviating from the biconcave disk shape, conservation of these shapes for imaging in general and 3D-imaging in particular, like confocal microscopy, scanning electron microscopy or scanning probe microscopy is a common desire. Along with the fixation comes an increase in the stiffness of the cells. In the context of red blood cells this increased rigidity is often used to mimic malaria infected red blood cells because they are also stiffer than healthy red blood cells. However, the use of glutaraldehyde is associated with numerous pitfalls: (i) while the increase in rigidity by an application of increasing concentrations of glutaraldehyde is an analog process, the fixation is a rather digital event (all or none); (ii) addition of glutaraldehyde massively changes osmolality in a concentration dependent manner and hence cell shapes can be distorted; (iii) glutaraldehyde batches differ in their properties especially in the ratio of monomers and polymers; (iv) handling pitfalls, like inducing shear artifacts of red blood cell shapes or cell density changes that needs to be considered, e.g., when working with cells in flow; (v) staining glutaraldehyde treated red blood cells need different approaches compared to living cells, for instance, because glutaraldehyde itself induces a strong fluorescence. Within this paper we provide documentation about the subtle use of glutaraldehyde on healthy and pathologic red blood cells and how to deal with or circumvent pitfalls.
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Affiliation(s)
- Asena Abay
- Dynamics of Fluids, Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Landsteiner Laboratory, Sanquin, Amsterdam, Netherlands
| | - Greta Simionato
- Dynamics of Fluids, Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany
| | - Revaz Chachanidze
- Dynamics of Fluids, Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Université Grenoble Alpes, CNRS, Grenoble INP, LRP, Grenoble, France
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Laura Hertz
- Dynamics of Fluids, Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany
| | - Paola Bianchi
- UOC Ematologia, UOS Fisiopatologia delle Anemie, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | | | - Marc Leonetti
- Université Grenoble Alpes, CNRS, Grenoble INP, LRP, Grenoble, France
| | - Giampaolo Minetti
- Laboratory of Biochemistry, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Christian Wagner
- Dynamics of Fluids, Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg City, Luxembourg
| | - Lars Kaestner
- Dynamics of Fluids, Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany
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20
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Yang Y, Xia M, Zhao H, Zhang S, Zhang X. A Cell-Surface-Specific Ratiometric Fluorescent Probe for Extracellular pH Sensing with Solid-State Fluorophore. ACS Sens 2018; 3:2278-2285. [PMID: 30350591 DOI: 10.1021/acssensors.8b00514] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Extracellular acidity is correlated with the development of various pathological states and bulk pH measurements could not report surface acidity. In this study, we have developed a ratiometric fluorescent probe that aggregates upon interaction with cells, allowing persistent labeling of cells and in situ measurement of cell surface pH. The ternary nanoplatform is constructed by a convenient noncovalent combination of bovine serum albumin protected gold nanoclusters (BSA-AuNCs), fluorescein isothiocyanate (FITC) labeled cationic peptides (CPs), and FITC-free CPs. The red fluorescent AuNCs serve as reference fluorophore, while FITC labeled peptides act as specific recognition element for H+ and FITC unlabeled peptides are used for delivery. The probe displays a sensitive fluorescence ratiometric response for pH in the range of 5.0-9.5 with calculated p Ka of 7.2. Further studies have demonstrated that this nanosensor also has properties of high selectivity, reversibility to pH fluctuations, as well as low cytotoxicity. The new surface pH-measurement tool was validated in mapping extracellular pH and monitoring acidification regarding cell metabolism, demonstrating its potential for bioimaging and biosensing.
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Affiliation(s)
- Yan Yang
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, P.R. China
| | - Mengchan Xia
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, P.R. China
| | - Hansen Zhao
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, P.R. China
| | - Sichun Zhang
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, P.R. China
| | - Xinrong Zhang
- Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, P.R. China
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21
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Mellanby RJ, Scott JI, Mair I, Fernandez A, Saul L, Arlt J, Moral M, Vendrell M. Tricarbocyanine N-triazoles: the scaffold-of-choice for long-term near-infrared imaging of immune cells in vivo. Chem Sci 2018; 9:7261-7270. [PMID: 30288247 PMCID: PMC6148684 DOI: 10.1039/c8sc00900g] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 07/30/2018] [Indexed: 12/17/2022] Open
Abstract
Herein tricarbocyanine N-triazoles are first described as a rationally-designed near-infrared (NIR) structure overcoming the brightness and photostability limitations of tricarbocyanines for long-term in vivo imaging. The straightforward synthetic approach and the wide availability of alkynes makes this strategy a versatile methodology for the preparation of highly stable N-substituted tricarbocyanines. Furthermore, we validated CIR38M as a non-transferable marker to monitor the fate of therapeutic T cells non-invasively in vivo, showing enhanced performance over conventional NIR fluorophores (i.e. DiR, IR800CW and indocyanine green) as well as compatibility with human cells for translational studies. CIR38M is able to track over time smaller numbers of T cells than current NIR agents, and to visualise antigen-driven accumulation of immune cells at specific sites in vivo. This chemical technology will improve longitudinal imaging studies to assess the efficacy of cell-based immunotherapies in preclinical models and in human samples.
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Affiliation(s)
- Richard J Mellanby
- Medical Research Council Centre for Inflammation Research , The University of Edinburgh , 47 Little France Crescent , EH16 4TJ Edinburgh , UK .
- Royal (Dick) School of Veterinary Studies , The Roslin Institute , Division of Veterinary Clinical Studies , The University of Edinburgh , Hospital for Small Animals , Easter Bush Veterinary Centre , EH25 9RG Roslin , UK .
| | - Jamie I Scott
- Medical Research Council Centre for Inflammation Research , The University of Edinburgh , 47 Little France Crescent , EH16 4TJ Edinburgh , UK .
| | - Iris Mair
- Medical Research Council Centre for Inflammation Research , The University of Edinburgh , 47 Little France Crescent , EH16 4TJ Edinburgh , UK .
| | - Antonio Fernandez
- Medical Research Council Centre for Inflammation Research , The University of Edinburgh , 47 Little France Crescent , EH16 4TJ Edinburgh , UK .
| | - Louise Saul
- Royal (Dick) School of Veterinary Studies , The Roslin Institute , Division of Veterinary Clinical Studies , The University of Edinburgh , Hospital for Small Animals , Easter Bush Veterinary Centre , EH25 9RG Roslin , UK .
| | - Jochen Arlt
- School of Physics and Astronomy , The University of Edinburgh , James Clerk Maxwell Building, Peter Guthrie Tait Road , EH9 3FD Edinburgh , UK
| | - Monica Moral
- Renewable Energy Research Institute , University of Castilla-La Mancha , 02071 Albacete , Spain
| | - Marc Vendrell
- Medical Research Council Centre for Inflammation Research , The University of Edinburgh , 47 Little France Crescent , EH16 4TJ Edinburgh , UK .
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22
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Schoenauer R, Larpin Y, Babiychuk EB, Drücker P, Babiychuk VS, Avota E, Schneider-Schaulies S, Schumacher F, Kleuser B, Köffel R, Draeger A. Down‐regulation of acid sphingomyelinase and neutral sphingomyelinase‐2 inversely determines the cellular resistance to plasmalemmal injury by pore‐forming toxins. FASEB J 2018; 33:275-285. [DOI: 10.1096/fj.201800033r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Roman Schoenauer
- Department of Cell BiologyInstitute of AnatomyUniversity of Bern Bern Switzerland
| | - Yu Larpin
- Department of Cell BiologyInstitute of AnatomyUniversity of Bern Bern Switzerland
| | - Eduard B. Babiychuk
- Department of Cell BiologyInstitute of AnatomyUniversity of Bern Bern Switzerland
| | - Patrick Drücker
- Department of Cell BiologyInstitute of AnatomyUniversity of Bern Bern Switzerland
| | | | - Elita Avota
- Institute of Virology and ImmunobiologyUniversity of Würzburg Würzburg Germany
| | | | - Fabian Schumacher
- Institute of Nutritional ScienceUniversity of Potsdam Potsdam Germany
| | - Burkhard Kleuser
- Institute of Nutritional ScienceUniversity of Potsdam Potsdam Germany
| | - René Köffel
- Department of Cell BiologyInstitute of AnatomyUniversity of Bern Bern Switzerland
| | - Annette Draeger
- Department of Cell BiologyInstitute of AnatomyUniversity of Bern Bern Switzerland
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23
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Sergievich LA, Karnaukhova EV, Karnaukhov AV, Karnaukhova NA, Bogdanenko EV, Lizunova IA, Karnaukhov VN. The Effect of Cryopreservation of Bone Marrow Cells from Donor Mice that Carry the egfp Gene, on the Lifespan of Mice after Syngeneic Transplantation. Biophysics (Nagoya-shi) 2018. [DOI: 10.1134/s0006350918030223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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24
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Czuba E, Diop M, Mura C, Schaschkow A, Langlois A, Bietiger W, Neidl R, Virciglio A, Auberval N, Julien-David D, Maillard E, Frere Y, Marchioni E, Pinget M, Sigrist S. Oral insulin delivery, the challenge to increase insulin bioavailability: Influence of surface charge in nanoparticle system. Int J Pharm 2018; 542:47-55. [DOI: 10.1016/j.ijpharm.2018.02.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/16/2018] [Accepted: 02/27/2018] [Indexed: 12/25/2022]
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25
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van Lith SA, van den Brand D, Wallbrecher R, Wübbeke L, van Duijnhoven SM, Mäkinen PI, Hoogstad-van Evert JS, Massuger L, Ylä-Herttuala S, Brock R, Leenders WP. The effect of subcellular localization on the efficiency of EGFR-targeted VHH photosensitizer conjugates. Eur J Pharm Biopharm 2018; 124:63-72. [DOI: 10.1016/j.ejpb.2017.12.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 12/11/2017] [Accepted: 12/19/2017] [Indexed: 12/19/2022]
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26
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Galloway JM, Senior L, Fletcher JM, Beesley JL, Hodgson LR, Harniman RL, Mantell JM, Coombs J, Rhys GG, Xue WF, Mosayebi M, Linden N, Liverpool TB, Curnow P, Verkade P, Woolfson DN. Bioinspired Silicification Reveals Structural Detail in Self-Assembled Peptide Cages. ACS NANO 2018; 12:1420-1432. [PMID: 29275624 PMCID: PMC5967840 DOI: 10.1021/acsnano.7b07785] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/24/2017] [Indexed: 05/25/2023]
Abstract
Understanding how molecules in self-assembled soft-matter nanostructures are organized is essential for improving the design of next-generation nanomaterials. Imaging these assemblies can be challenging and usually requires processing, e.g., staining or embedding, which can damage or obscure features. An alternative is to use bioinspired mineralization, mimicking how certain organisms use biomolecules to template mineral formation. Previously, we have reported the design and characterization of Self-Assembled peptide caGEs (SAGEs) formed from de novo peptide building blocks. In SAGEs, two complementary, 3-fold symmetric, peptide hubs combine to form a hexagonal lattice, which curves and closes to form SAGE nanoparticles. As hexagons alone cannot tile onto spheres, the network must also incorporate nonhexagonal shapes. While the hexagonal ultrastructure of the SAGEs has been imaged, these defects have not been observed. Here, we show that positively charged SAGEs biotemplate a thin, protective silica coating. Electron microscopy shows that these SiO2-SAGEs do not collapse, but maintain their 3D shape when dried. Atomic force microscopy reveals a network of hexagonal and irregular features on the SiO2-SAGE surface. The dimensions of these (7.2 nm ± 1.4 nm across, internal angles 119.8° ± 26.1°) are in accord with the designed SAGE network and with coarse-grained modeling of the SAGE assembly. The SiO2-SAGEs are permeable to small molecules (<2 nm), but not to larger biomolecules (>6 nm). Thus, bioinspired silicification offers a mild technique that preserves soft-matter nanoparticles for imaging, revealing structural details <10 nm in size, while also maintaining desirable properties, such as permeability to small molecules.
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Affiliation(s)
- Johanna M. Galloway
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K.
| | - Laura Senior
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
| | - Jordan M. Fletcher
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K.
| | - Joseph L. Beesley
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K.
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
| | - Lorna R. Hodgson
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
| | - Robert L. Harniman
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K.
| | - Judith M. Mantell
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
- Wolfson
Bioimaging Facility, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
| | - Jennifer Coombs
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
- Bristol
Centre for Functional Nanomaterials, NSQI, University of Bristol, Tyndall Avenue, Bristol, BS8 1FD, U.K.
| | - Guto G. Rhys
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K.
| | - Wei-Feng Xue
- School
of Biosciences, Stacy Building, University
of Kent, Canterbury, CT2 7NJ, U.K.
| | - Majid Mosayebi
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, U.K.
- School of
Mathematics, University of Bristol, University Walk, Bristol, BS8 1TW, U.K.
| | - Noah Linden
- School of
Mathematics, University of Bristol, University Walk, Bristol, BS8 1TW, U.K.
| | - Tanniemola B. Liverpool
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, U.K.
- School of
Mathematics, University of Bristol, University Walk, Bristol, BS8 1TW, U.K.
| | - Paul Curnow
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, U.K.
| | - Paul Verkade
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
- Wolfson
Bioimaging Facility, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, U.K.
| | - Derek N. Woolfson
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol, BS8 1TS, U.K.
- School
of Biochemistry, University of Bristol, Biomedical Sciences Building, University
Walk, Bristol, BS8 1TD, U.K.
- BrisSynBio, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, U.K.
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Immunotherapy with subcutaneous immunogenic autologous tumor lysate increases murine glioblastoma survival. Sci Rep 2017; 7:13902. [PMID: 29066810 PMCID: PMC5654749 DOI: 10.1038/s41598-017-12584-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 08/08/2017] [Indexed: 02/06/2023] Open
Abstract
Immunotherapeutic strategies for glioblastoma, the most frequent malignant primary brain tumor, aim to improve its disastrous consequences. On top of the standard treatment, one strategy uses T cell activation by autologous dendritic cells (DC) ex vivo loaded with tumor lysate to attack remaining cancer cells. Wondering whether 'targeting' in vivo DCs could replace these ex vivo ones, immunogenic autologous tumor lysate was used to treat glioma-inoculated mice in the absence of ex vivo loaded DCs. Potential immune mechanisms were studied in two orthotopic, immunocompetent murine glioma models. Pre-tumoral subcutaneous lysate treatment resulted in a survival benefit comparable to subcutaneous DC therapy. Focussing on the immune response, glioma T cell infiltration was observed in parallel with decreased amounts of regulatory T cells. Moreover, these results were accompanied by the presence of strong tumor-specific immunological memory, shown by complete survival of a second glioblastoma tumor, inoculated 100 days after the first one. Finally, in combination with temozolomide, survival of established glioma in mice could be increased. Our results show the potential of immunogenic autologous tumor lysate used to treat murine glioblastoma, which will be worthwhile to study in clinical trials as it has potential as a cost-efficient adjuvant treatment strategy for gliomas.
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28
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Yang J, Yang F, Campos LS, Mansfield W, Skelton H, Hooks Y, Liu P. Quenching autofluorescence in tissue immunofluorescence. Wellcome Open Res 2017. [DOI: 10.12688/wellcomeopenres.12251.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background: Immunofluorescence (IF) is one of the most important techniques where fluorochromes conjugated to antibodies are used to detect specific proteins or antigens. In tissue sections, autofluorescence (AF) can lead to poor quality images that impair assessment. The placenta is a pivotal extra-embryonic organ in embryo development, where trophoblasts make up a large proportion of the cells. Teratoma formation is one of the critical assays for pluripotent stem cells. Methods: We tested whether ultraviolet (UV), ammonia (NH3), copper (II) sulfate (CuSO4), Trypan Blue (TB), Sudan Black B (SB), TrueBlack™ Lipofusin Autofluorescence Quencher (TLAQ) and combinations of these treatments could reduce AF in paraffin and frozen sections of placenta and teratoma in FITC, Texas Red and Cy5.5 channels. Results: We found that UV, NH3, TB and CuSO4 quenched AF to some extent in different tissue and filters, but increased AF in Texas Red or Cy5.5 channels in some cases. SB and TLQA exhibited the most consistent effects on decreasing AF, though TLQA reduced the overall IF signal in placenta sections. Not all combined treatments further reduced AF in both placenta and teratoma sections. Conclusions: SB and TLAQ can effectively quench AF in placenta and teratoma IF.
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Amino Acid Differences in the 1753-to-1851 Region of TcdB Influence Variations in TcdB1 and TcdB2 Cell Entry. mSphere 2017; 2:mSphere00268-17. [PMID: 28776043 PMCID: PMC5541160 DOI: 10.1128/msphere.00268-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 07/13/2017] [Indexed: 01/24/2023] Open
Abstract
Clostridium difficile TcdB2 enters cells with a higher efficiency than TcdB1 and exhibits an overall higher level of toxicity. However, the TcdB2-specific sequences that account for more efficient cell entry have not been reported. In this study, we examined the contribution of carboxy-terminal sequence differences to TcdB activity by comparing the binding, uptake, and endosomal localization of TcdB1 and TcdB2 or selected recombinant fragments of these proteins. Our findings suggest that sequence differences in the amino acid 1753 to 1851 region proximal to the combined repetitive oligopeptide domain (CROP) support enhanced uptake of TcdB2 and localization of toxin in acidified endosomes. In the absence of this region, the CROP domains of both forms of the toxin exhibited similar levels of cell interaction, while the addition of amino acids 1753 to 1851 greatly increased toxin binding by only TcdB2. Moreover, the amino acid 1753 to 2366 fragment of TcdB2, but not TcdB1, accumulated to detectable levels in acidified endosomes. Unexpectedly, we discovered an unusual relationship between endocytosis and the efficiency of cell binding for TcdB1 and TcdB2 wherein inhibition of endocytosis by a chemical inhibitor or incubation at a low temperature resulted in a dramatic reduction in cell binding. These findings provide information on sequence variations that may contribute to differences in TcdB1 and TcdB2 toxicity and reveal a heretofore unknown connection between endocytosis and cell binding for this toxin. IMPORTANCE TcdB is a major virulence factor produced by Clostridium difficile, a leading cause of antibiotic-associated diarrhea. Hypervirulent strains of C. difficile encode a variant of TcdB (TcdB2) that is more toxic than toxin derived from historical strains (TcdB1). Though TcdB1 and TcdB2 exhibit 92% overall identity, a 99-amino-acid region previously associated with cell entry and spanning amino acids 1753 to 1851 has only 77% sequence identity. Results from the present study indicate that the substantial sequence variation in this region could contribute to the differences in cell entry between TcdB1 and TcdB2 and possibly explain TcdB2's heightened toxicity. Finally, during the course of these studies, an unusual aspect of TcdB cell entry was discovered wherein cell binding appeared to depend on endocytosis. These findings provide insight into TcdB's variant forms and their mechanisms of cell entry.
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Karpowicz RJ, Haney CM, Mihaila TS, Sandler RM, Petersson EJ, Lee VMY. Selective imaging of internalized proteopathic α-synuclein seeds in primary neurons reveals mechanistic insight into transmission of synucleinopathies. J Biol Chem 2017; 292:13482-13497. [PMID: 28611062 DOI: 10.1074/jbc.m117.780296] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 06/11/2017] [Indexed: 11/06/2022] Open
Abstract
Direct cell-to-cell transmission of proteopathic α-synuclein (α-syn) aggregates is thought to underlie the progression of neurodegenerative synucleinopathies. However, the specific intracellular processes governing this transmission remain unclear because currently available model systems are limited. For example, in cell culture models of α-syn-seeded aggregation, it is difficult to discern intracellular from extracellular exogenously applied α-syn seed species. Herein, we employed fluorescently labeled α-syn preformed fibrils (pffs) in conjunction with the membrane-impermeable fluorescence quencher trypan blue to selectively image internalized α-syn seeds in cultured primary neurons and to quantitatively characterize the concentration dependence, time course, and inhibition of pff uptake. To study the long-term fates of exogenous α-syn pffs in neurons, we developed a pff species labeled at amino acid residue 114 with the environmentally insensitive fluorophore BODIPY or the pH-sensitive dye pHrodo red. We found that pffs are rapidly trafficked along the endolysosomal pathway, where most of the material remains for days. We also found that brief pharmacological perturbation of lysosomes shortly after the pff treatment causes aberrations in intracellular processing of pff seeds concomitant with an increased rate of inclusion formation via recruitment of endogenous α-syn to a relatively small number of exogenous seeds. Our results validate a quantitative assay for pff uptake in primary neurons, implicate lysosomal processing as the major fate of internalized proteopathic seeds, and suggest lysosomal integrity as a significant rate-determining step in the transmission of α-syn pathology. Further, lysosomal processing of transmitted seeds may represent a new therapeutic target to combat the spread of synucleinopathies.
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Affiliation(s)
- Richard J Karpowicz
- From the Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, and
| | - Conor M Haney
- the Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Tiberiu S Mihaila
- the Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Raizel M Sandler
- From the Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, and
| | - E James Petersson
- the Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Virginia M-Y Lee
- From the Center for Neurodegenerative Disease Research, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, and
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31
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Matsubara T, Otani R, Yamashita M, Maeno H, Nodono H, Sato T. Selective Intracellular Delivery of Ganglioside GM3-Binding Peptide through Caveolae/Raft-Mediated Endocytosis. Biomacromolecules 2017; 18:355-362. [DOI: 10.1021/acs.biomac.6b01262] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Teruhiko Matsubara
- Department of Biosciences
and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
| | - Ryohei Otani
- Department of Biosciences
and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
| | - Miki Yamashita
- Department of Biosciences
and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
| | - Haruka Maeno
- Department of Biosciences
and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
| | - Hanae Nodono
- Department of Biosciences
and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
| | - Toshinori Sato
- Department of Biosciences
and Informatics, Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522, Japan
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32
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Martucci NM, Migliaccio N, Ruggiero I, Albano F, Calì G, Romano S, Terracciano M, Rea I, Arcari P, Lamberti A. Nanoparticle-based strategy for personalized B-cell lymphoma therapy. Int J Nanomedicine 2016; 11:6089-6101. [PMID: 27895482 PMCID: PMC5117954 DOI: 10.2147/ijn.s118661] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
B-cell lymphoma is associated with incomplete response to treatment, and the development of effective strategies targeting this disease remains challenging. A new personalized B-cell lymphoma therapy, based on a site-specific receptor-mediated drug delivery system, was developed in this study. Specifically, natural silica-based nanoparticles (diatomite) were modified to actively target the antiapoptotic factor B-cell lymphoma/leukemia 2 (Bcl2) with small interfering RNA (siRNA). An idiotype-specific peptide (Id-peptide) specifically recognized by the hypervariable region of surface immunoglobulin B-cell receptor was exploited as a homing device to ensure specific targeting of lymphoma cells. Specific nanoparticle uptake, driven by the Id-peptide, was evaluated by flow cytometry and confocal microscopy and was increased by approximately threefold in target cells compared with nonspecific myeloma cells and when a random control peptide was used instead of Id-peptide. The specific internalization efficiency was increased by fourfold when siRNA was also added to the modified nanoparticles. The modified diatomite particles were not cytotoxic and their effectiveness in downregulation of gene expression was explored using siRNA targeting Bcl2 and evaluated by quantitative real-time polymerase chain reaction and Western blot analyses. The resulting gene silencing observed is of significant biological importance and opens new possibilities for the personalized treatment of lymphomas.
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Affiliation(s)
- Nicola M Martucci
- Department of Molecular Medicine and Medical Biotechnology, University Federico II of Naples, Naples
| | - Nunzia Migliaccio
- Department of Molecular Medicine and Medical Biotechnology, University Federico II of Naples, Naples
| | - Immacolata Ruggiero
- Department of Molecular Medicine and Medical Biotechnology, University Federico II of Naples, Naples
| | - Francesco Albano
- Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Graecia", Catanzaro
| | - Gaetano Calì
- Institute of Endocrinology and Molecular Oncology
| | - Simona Romano
- Department of Molecular Medicine and Medical Biotechnology, University Federico II of Naples, Naples
| | - Monica Terracciano
- Institute for Microelectronics and Microsystems, National Research Council, Naples, Italy
| | - Ilaria Rea
- Institute for Microelectronics and Microsystems, National Research Council, Naples, Italy
| | - Paolo Arcari
- Department of Molecular Medicine and Medical Biotechnology, University Federico II of Naples, Naples
| | - Annalisa Lamberti
- Department of Molecular Medicine and Medical Biotechnology, University Federico II of Naples, Naples
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33
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Abstract
We have developed a way to measure cell surface pH by positioning a pH-sensitive fluorescent dye, seminaphtharhodafluor (SNARF), conjugated to the pH low insertion peptide (pHLIP). It has been observed that many diseased tissues are acidic and that tumors are especially so. A combination of effects acidifies tumor cell interiors, and cells pump out lactic acid and protons to maintain intracellular pH, acidifying the extracellular space. Overexpression of carbonic anhydrases on cell surfaces further contributes to acidification. Thus, the pH near tumor cell surfaces is expected to be low and to increase with distance from the membrane, so bulk pH measurements will not report surface acidity. Our new surface pH-measurement tool was validated in cancer cells grown in spheroids, in mouse tumor models in vivo, and in excised tumors. We found that the surface pH is sensitive to cell glycolytic activity: the pH decreases in high glucose and increases if glucose is replaced with nonmetabolized deoxyglucose. For highly metastatic cancer cells, the pH measured at the surface was 6.7-6.8, when the surrounding external pH was 7.4. The approach is sensitive enough to detect 0.2-0.3 pH unit changes in vivo in tumors induced by i.p. injection of glucose. The pH at the surfaces of highly metastatic cells within tumors was found to be about 6.1-6.4, whereas in nonmetastatic tumors, it was 6.7-6.9, possibly creating a way to distinguish more aggressive from less aggressive tumors. Other biological roles of surface acidity may be found, now that targeted measurements are possible.
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34
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Delafosse L, Xu P, Durocher Y. Comparative study of polyethylenimines for transient gene expression in mammalian HEK293 and CHO cells. J Biotechnol 2016; 227:103-111. [DOI: 10.1016/j.jbiotec.2016.04.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Revised: 03/30/2016] [Accepted: 04/12/2016] [Indexed: 01/28/2023]
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35
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Dill BD, Gierlinski M, Härtlova A, Arandilla AG, Guo M, Clarke RG, Trost M. Quantitative proteome analysis of temporally resolved phagosomes following uptake via key phagocytic receptors. Mol Cell Proteomics 2015; 14:1334-49. [PMID: 25755298 PMCID: PMC4424403 DOI: 10.1074/mcp.m114.044594] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 02/26/2015] [Indexed: 12/31/2022] Open
Abstract
Macrophages operate at the forefront of innate immunity and their discrimination of foreign versus "self" particles is critical for a number of responses including efficient pathogen killing, antigen presentation, and cytokine induction. In order to efficiently destroy the particles and detect potential threats, macrophages express an array of receptors to sense and phagocytose prey particles. In this study, we accurately quantified a proteomic time-course of isolated phagosomes from murine bone marrow-derived macrophages induced by particles conjugated to seven different ligands representing pathogen-associated molecular patterns, immune opsonins or apoptotic cell markers. We identified a clear functional differentiation over the three timepoints and detected subtle differences between certain ligand-phagosomes, indicating that triggering of receptors through a single ligand type has mild, but distinct, effects on phagosome proteome and function. Moreover, our data shows that uptake of phosphatidylserine-coated beads induces an active repression of NF-κB immune responses upon Toll-like receptor (TLR)-activation by recruitment of anti-inflammatory regulators to the phagosome. This data shows for the first time a systematic time-course analysis of bone marrow-derived macrophages phagosomes and how phagosome fate is regulated by the receptors triggered for phagocytosis.
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Affiliation(s)
- Brian D Dill
- From the ‡MRC Protein Phosphorylation and Ubiquitylation Unit
| | | | - Anetta Härtlova
- From the ‡MRC Protein Phosphorylation and Ubiquitylation Unit
| | | | - Manman Guo
- From the ‡MRC Protein Phosphorylation and Ubiquitylation Unit
| | - Rosemary G Clarke
- ¶Division of Cell Signalling and Immunology, University of Dundee, Scotland, DD1 5EH, United Kingdom
| | - Matthias Trost
- From the ‡MRC Protein Phosphorylation and Ubiquitylation Unit,
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36
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Kuo CL, Chen TS, Liou SY, Hsieh CC. Immunomodulatory effects of EGCG fraction of green tea extract in innate and adaptive immunity via T regulatory cells in murine model. Immunopharmacol Immunotoxicol 2014; 36:364-70. [PMID: 25151997 DOI: 10.3109/08923973.2014.953637] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Green tea is a widely consumed beverage known for its beneficial anti-inflammatory, anti-oxidative, anti-mutagenic, anti-carcinogenic, and cardioprotective properties. Here, we administered epigallocatechin gallate fraction of green tea extract (EGTE) to mice for 6 weeks and examined the effects on the innate and adaptive immune responses by measuring phagocytic and natural killer (NK) cell activity, as well as antigen-specific proliferation, cytolysis, cytokine secretion, and antibody production. Our data show that EGTE administration increased NK cell cytolysis and peritoneal cell phagocytosis, as well as splenocyte proliferation and secretion of IL-2 and IFN-γ. Of note, EGTE treatment decreased the production antigen-specific IgE via increased the proportion of CD4+ CD25+ regulatory T lymphocytes in the spleen, suggesting that EGTE may play a role in regulating the allergic response.
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Affiliation(s)
- Chao-Lin Kuo
- Department of Chinese Pharmaceutical Sciences and Chinese Medicine Resources, China Medical University , Taichung, Taiwan , ROC
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37
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Indrasekara ASDS, Paladini BJ, Naczynski DJ, Starovoytov V, Moghe PV, Fabris L. Dimeric gold nanoparticle assemblies as tags for SERS-based cancer detection. Adv Healthc Mater 2013; 2:1370-6. [PMID: 23495174 DOI: 10.1002/adhm.201200370] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 11/19/2012] [Indexed: 01/21/2023]
Abstract
Herein, a new class of multifunctional materials combining a clustered nanoparticle-based probe is presented for surface enhanced Raman scattering (SERS)-based microscopy and surface functionalization for tissue targeting. Controlled assembly of spherical gold nanoparticles into dimers (DNP-REP) is engineered using a small, rigid Raman-active dithiolated linking reporter (REP) to yield narrow internanoparticle gaps and to strategically generate the "hot spot" while concurrently placing the reporter within the region of highest SERS enhancement. Peptide functionalized DNP-REP materials are highly stable even upon incubation with living cells and show controlled levels of binding and intracellular endocytosis. To demonstrate the functionality of such probes for disease detection, differentially targeted DNP-REPs are incubated over various time points with cultured human glioblastoma cells. Using human glioblastoma cells, the SERS maps of targeted tumor cells show the markedly enhanced signals of the DNP-REP, compared to conventional confocal fluorescence based approaches, especially at low incubation times. Even with as few as 40 internalized DNP-REP, a relatively intense SERS signal is measured, demonstrating the high signal to noise ratio and inherent biocompatibility of the materials. Thus, these Raman reporter-based nanoparticle cluster probes present a promising and versatile optical imaging tool for fast, reliable, selective, and ultrasensitive tissue targeting and disease detection and screening.
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Affiliation(s)
- A Swarnapali D S Indrasekara
- Department of Materials Science and Engineering, Institute for Advanced Materials Devices and Nanotechnology, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, USA
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38
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Teague H, Rockett BD, Harris M, Brown DA, Shaikh SR. Dendritic cell activation, phagocytosis and CD69 expression on cognate T cells are suppressed by n-3 long-chain polyunsaturated fatty acids. Immunology 2013; 139:386-94. [PMID: 23373457 DOI: 10.1111/imm.12088] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 01/09/2013] [Accepted: 01/30/2013] [Indexed: 12/14/2022] Open
Abstract
Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are bioactive n-3 long-chain polyunsaturated fatty acids (LCPUFAs) in fish oil that exert immunosuppressive effects. A significant amount of literature shows that n-3 LCPUFAs suppress dendritic cell (DC) function in vitro; however, few studies have determined if the effects are emulated at the animal level. In this study, we first focused on the functional consequences of 5% (weight/weight) fish oil on splenic CD11c(+) DCs. Administration of n-3 LCPUFAs, modelling human pharmacological intake (2% of total kcal from EPA,1·3% from DHA), to C57BL/6 mice for 3 weeks reduced DC surface expression of CD80 by 14% and tumour necrosis factor-α secretion by 29% upon lipopolysaccharide stimulation relative to a control diet. The n-3 LCPUFAs also significantly decreased CD11c(+) surface expression and phagocytosis by 12% compared with the control diet. Antigen presentation studies revealed a 22% decrease in CD69 surface expression on transgenic CD4(+) T lymphocytes activated by DCs from mice fed fish oil. We then determined if the functional changes were mechanistically associated with changes in lipid microdomain clustering or plasma membrane microviscosity with n-3 LCPUFAs, as reported for B and T lymphocytes. Fish oil administration to mice did not influence cholera-toxin induced lipid microdomain clustering or microviscosity, even though EPA and DHA levels were significantly elevated relative to the control diet. Overall, our data show that n-3 LCPUFAs exert immunosuppressive effects on DCs, validating in vitro studies. The results also show that DC microdomain clustering and microviscosity were not changed by the n-3 LCPUFA intervention used in this study.
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Affiliation(s)
- Heather Teague
- Department of Biochemistry and Molecular Biology, East Carolina University, Greenville, NC, USA
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Islam MA, Pröll M, Hölker M, Tholen E, Tesfaye D, Looft C, Schellander K, Cinar MU. Alveolar macrophage phagocytic activity is enhanced with LPS priming, and combined stimulation of LPS and lipoteichoic acid synergistically induce pro-inflammatory cytokines in pigs. Innate Immun 2013; 19:631-43. [PMID: 23608822 DOI: 10.1177/1753425913477166] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The objective of the present study was to investigate LPS and lipoteichoic acid (LTA)-induced TLRs, associated signaling molecules and inflammatory mediators, as well as to compare their combined effect in porcine alveolar macrophages. Macrophages were incubated for 24 h with various concentrations of LPS, LTA, LPS + LTA or control. Multiple concentrations of LPS elicited marked up-regulation in mRNA for TLR2 and TLR4, CD14, MD2, MyD88, IRAK-4 and TRAF6 compared with the control. LTA had no effect on TLR4 and MD2; only higher doses up-regulated TLR2, CD14, MyD88, IRAK-4 and TRAF6 mRNA. LPS-activated cells released IL1-β, IL12-β, TNF-α, IL-6, IL-8, IFN-γ and IL-10 in a dose-dependent manner, while LTA had no effect on IL-1β, IL-6 and IFN-γ. Higher doses of LTA induced IL-12β, TNF-α, IL-8 and IL-10. Combined stimulation augmented TLR2, CD14 and MyD88 mRNA, and subsequently produced elevated levels of IL-6, TNF-α and IL-8 when compared with LPS and LTA alone. Additionally, phagocytosis of macrophages was significantly increased following low concentration of LPS treatment. Only low levels of NO (nitric oxide) were detected in the LPS group. Overall, compared with LPS, LTA was a relatively weak inducer, and co-stimulation accelerated gene and cytokine production associated with pulmonary innate immune function.
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Vranic S, Boggetto N, Contremoulins V, Mornet S, Reinhardt N, Marano F, Baeza-Squiban A, Boland S. Deciphering the mechanisms of cellular uptake of engineered nanoparticles by accurate evaluation of internalization using imaging flow cytometry. Part Fibre Toxicol 2013; 10:2. [PMID: 23388071 PMCID: PMC3599262 DOI: 10.1186/1743-8977-10-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 02/03/2013] [Indexed: 01/08/2023] Open
Abstract
Background The uptake of nanoparticles (NPs) by cells remains to be better characterized in order to understand the mechanisms of potential NP toxicity as well as for a reliable risk assessment. Real NP uptake is still difficult to evaluate because of the adsorption of NPs on the cellular surface. Results Here we used two approaches to distinguish adsorbed fluorescently labeled NPs from the internalized ones. The extracellular fluorescence was either quenched by Trypan Blue or the uptake was analyzed using imaging flow cytometry. We used this novel technique to define the inside of the cell to accurately study the uptake of fluorescently labeled (SiO2) and even non fluorescent but light diffracting NPs (TiO2). Time course, dose-dependence as well as the influence of surface charges on the uptake were shown in the pulmonary epithelial cell line NCI-H292. By setting up an integrative approach combining these flow cytometric analyses with confocal microscopy we deciphered the endocytic pathway involved in SiO2 NP uptake. Functional studies using energy depletion, pharmacological inhibitors, siRNA-clathrin heavy chain induced gene silencing and colocalization of NPs with proteins specific for different endocytic vesicles allowed us to determine macropinocytosis as the internalization pathway for SiO2 NPs in NCI-H292 cells. Conclusion The integrative approach we propose here using the innovative imaging flow cytometry combined with confocal microscopy could be used to identify the physico-chemical characteristics of NPs involved in their uptake in view to redesign safe NPs.
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Affiliation(s)
- Sandra Vranic
- Univ Paris Diderot, Sorbonne Paris Cité, Laboratory of Molecular and Cellular Responses to Xenobiotics, Unit of Functional and Adaptive Biology (BFA) EAC CNRS 4413, 5 rue Thomas Mann, Paris 75 013, France.
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Zhou H, Liao J, Aloor J, Nie H, Wilson BC, Fessler MB, Gao HM, Hong JS. CD11b/CD18 (Mac-1) is a novel surface receptor for extracellular double-stranded RNA to mediate cellular inflammatory responses. THE JOURNAL OF IMMUNOLOGY 2012; 190:115-25. [PMID: 23209319 DOI: 10.4049/jimmunol.1202136] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During viral infection, extracellular dsRNA is a potent signaling molecule that activates many innate immune cells, including macrophages. TLR3 is a well-known receptor for extracellular dsRNA, and internalization of extracellular dsRNA is required for endosomal TLR3 activation. Preserved inflammatory responses of TLR3-deficient macrophages to extracellular dsRNA strongly support a TLR3-independent mechanism in dsRNA-mediated immune responses. The present study demonstrated that CD11b/CD18 (Mac-1 [macrophage-1 Ag]), a surface integrin receptor, recognized extracellular dsRNA and induced macrophage immune responses. CD11b deficiency reduced inflammatory cytokine induction elicited by polyinosinic:polycytidylic acid (poly I:C; a synthetic dsRNA) in mouse sera and livers, as well as in cultured peritoneal macrophages. dsRNA-binding assay and confocal immunofluorescence showed that Mac-1, especially the CD11b subunit, interacted and colocalized with poly I:C on the surface of macrophages. Further mechanistic studies revealed two distinct signaling events following dsRNA recognition by Mac-1. First, Mac-1 facilitated poly I:C internalization through the activation of PI3K signaling and enhanced TLR3-dependent activation of IRF3 in macrophages. Second, poly I:C induced activation of phagocyte NADPH oxidase in a TLR3-independent, but Mac-1-dependent, manner. Subsequently, phagocyte NADPH oxidase-derived intracellular reactive oxygen species activated MAPK and NF-κB pathways. Our results indicate that extracellular dsRNA activates Mac-1 to enhance TLR3-dependent signaling and to trigger TLR3-independent, but Mac-1-dependent, inflammatory oxidative signaling, identifying a novel mechanistic basis for macrophages to recognize extracellular dsRNA to regulate innate immune responses. This study identifies Mac-1 as a novel surface receptor for extracellular dsRNA and implicates it as a potential therapeutic target for virus-related inflammatory diseases.
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Affiliation(s)
- Hui Zhou
- Laboratory of Toxicology and Pharmacology, National Institutes of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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Islam MA, Uddin MJ, Tholen E, Tesfaye D, Looft C, Schellander K, Cinar MU. Age-related changes in phagocytic activity and production of pro-inflammatory cytokines by lipopolysaccharide stimulated porcine alveolar macrophages. Cytokine 2012; 60:707-17. [PMID: 22974531 DOI: 10.1016/j.cyto.2012.08.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 07/09/2012] [Accepted: 08/10/2012] [Indexed: 11/16/2022]
Abstract
The aim of the present study was to determine the age-related changes of phagocytic capacity and the kinetic production of cytokines in lipopolysaccharide-stimulated porcine alveolar macrophages. For this purpose, AMs were isolated from 5 (newborn), 40 (post-weaned) and 120 (young) day old pigs. Results of phagocytosis assay showed that AMs from newborn piglets had less phagocytic capacity than those of young pigs (P<0.05). For the kinetics study, cells and supernatant were collected at 1, 6, 12, 24, 36 and 48 h after LPS stimulation for quantification of cytokine mRNA and protein by quantitative real-time PCR and ELISA, respectively. The kinetics results showed that AMs from newborn piglets were significantly less capable of producing IL1β, IL6, IL12β, TNFα and IL8 than post-weaned piglets or young pigs. IL18 mRNA did not show significant differences between ages. MIP2 and MCP1 mRNA was higher in young pigs. Hence, higher production of cytokines by AMs may be the surfactant factors in the pulmonary host defense system. These results indicate that AMs from newborn piglets might be functionally immature, which may lead to increased susceptibility to lung infections. Future studies of cytokine kinetics in more animals are clearly needed to confirm these results across a wider age range.
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Affiliation(s)
- Mohammad Ariful Islam
- Institute of Animal Science, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
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Coquery CM, Loo W, Buszko M, Lannigan J, Erickson LD. Optimized protocol for the isolation of spleen-resident murine neutrophils. Cytometry A 2012; 81:806-14. [PMID: 22760952 PMCID: PMC3548322 DOI: 10.1002/cyto.a.22096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 05/22/2012] [Accepted: 06/12/2012] [Indexed: 01/11/2023]
Abstract
Neutrophils are an important cellular component of the innate immune system that provides immediate protection to the host from infection. Neutrophil infiltration into inflamed peripheral tissues during infection is beneficial for immunity through phagocytosis of microbes, the release of antimicrobial factors, and secretion of proinflammatory cytokines. Recent reports further suggest that spleen-infiltrating neutrophils play a role in the adaptive immune response by providing survival signals to B cells. However, neutrophils may have detrimental effects on immunity in inflammatory diseases where their recruitment to lymphoid tissues and activation occur abnormally. To determine the contribution of neutrophils that reside in secondary lymphoid tissues to adaptive immunity, direct evaluation of the functional properties of tissue-resident neutrophils is required. We have developed a modified magnetic bead isolation approach for purifying neutrophils from inflamed spleens of autoimmune-prone mice by negative selection. Using this approach, we yielded neutrophils with greater than 90% purity without compromising cell viability. Equally important, the isolation procedure had little effect on the activation of neutrophils and did not impair phagocytic function. Thus, isolation of spleen-resident neutrophils by this optimized approach could be useful for interrogating the functional role of murine neutrophils in normal and abnormal immune responses.
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Affiliation(s)
- Christine M. Coquery
- Department of Microbiology, Immunology and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia
- Graduate Program in Microbiology, Immunology and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia
| | - William Loo
- Department of Microbiology, Immunology and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Maja Buszko
- Department of Microbiology, Immunology and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Joanne Lannigan
- Flow Cytometry Core Facility, School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Loren D. Erickson
- Department of Microbiology, Immunology and Cancer Biology, School of Medicine, University of Virginia, Charlottesville, Virginia
- Beirne B. Carter Center for Immunology Research, School of Medicine, University of Virginia, Charlottesville, Virginia
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Dementhon K, El-Kirat-Chatel S, Noël T. Development of an in vitro model for the multi-parametric quantification of the cellular interactions between Candida yeasts and phagocytes. PLoS One 2012; 7:e32621. [PMID: 22479332 PMCID: PMC3316538 DOI: 10.1371/journal.pone.0032621] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 02/02/2012] [Indexed: 11/18/2022] Open
Abstract
We developed a new in vitro model for a multi-parameter characterization of the time course interaction of Candida fungal cells with J774 murine macrophages and human neutrophils, based on the use of combined microscopy, fluorometry, flow cytometry and viability assays. Using fluorochromes specific to phagocytes and yeasts, we could accurately quantify various parameters simultaneously in a single infection experiment: at the individual cell level, we measured the association of phagocytes to fungal cells and phagocyte survival, and monitored in parallel the overall phagocytosis process by measuring the part of ingested fungal cells among the total fungal biomass that changed over time. Candida albicans, C. glabrata, and C. lusitaniae were used as a proof of concept: they exhibited species-specific differences in their association rate with phagocytes. The fungal biomass uptaken by the phagocytes differed significantly according to the Candida species. The measure of the survival of fungal and immune cells during the interaction showed that C. albicans was the more aggressive yeast in vitro, destroying the vast majority of the phagocytes within five hours. All three species of Candida were able to survive and to escape macrophage phagocytosis either by the intraphagocytic yeast-to-hyphae transition (C. albicans) and the fungal cell multiplication until phagocytes burst (C. glabrata, C. lusitaniae), or by the avoidance of phagocytosis (C. lusitaniae). We demonstrated that our model was sensitive enough to quantify small variations of the parameters of the interaction. The method has been conceived to be amenable to the high-throughput screening of mutants in order to unravel the molecular mechanisms involved in the interaction between yeasts and host phagocytes.
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Affiliation(s)
- Karine Dementhon
- Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Sofiane El-Kirat-Chatel
- Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Thierry Noël
- Univ. Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- * E-mail:
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Dual targeted delivery of doxorubicin to cancer cells using folate-conjugated magnetic multi-walled carbon nanotubes. Colloids Surf B Biointerfaces 2011; 89:1-9. [PMID: 21982868 DOI: 10.1016/j.colsurfb.2011.08.001] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 08/01/2011] [Accepted: 08/02/2011] [Indexed: 01/08/2023]
Abstract
By combining the advantage of multi-walled carbon nanotubes (MWCNTs) and iron oxide magnetic nanoparticles (MNs), we develop a magnetic dual-targeted nanocarrier for drug delivery. MWCNTs were functionalized with poly(acrylic acid) through free radical polymerization, decorated with MNs, conjugated with a targeting ligand folic acid (FA), for loading of an anti-cancer drug doxorubicin (DOX). The proposed methodology provides dual targeted delivery of the anti-cancer drug to cancer cells under the guidance of a magnetic field and through ligand-receptor interactions. The chemico-physical properties of the nanocarrier were characterized, in addition to its drug loading efficiency and drug releasing characteristics. Doxorubicin could be loaded to MWCNTs with high efficiency via π-π stacking and hydrogen bonding and showed enhanced cytotoxicity toward U87 human glioblastoma cells compared with free DOX. From transmission electron microscopy and confocal laser scanning microscopy, we confirmed that DOX-FA-MN-MWCNT could be efficiently taken up by U87 cells with subsequent intracellular release of DOX, followed by transport of DOX into the nucleus with the nanocarrier left in the cytoplasm. These properties make the magnetic nanocarrier a potential candidate for targeted delivery of DOX for cancer treatment.
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Mittal R, Sukumaran SK, Selvaraj SK, Wooster DG, Babu MM, Schreiber AD, Verbeek JS, Prasadarao NV. Fcγ receptor I alpha chain (CD64) expression in macrophages is critical for the onset of meningitis by Escherichia coli K1. PLoS Pathog 2010; 6:e1001203. [PMID: 21124939 PMCID: PMC2987830 DOI: 10.1371/journal.ppat.1001203] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 10/21/2010] [Indexed: 11/18/2022] Open
Abstract
Neonatal meningitis due to Escherichia coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The lack of a comprehensive understanding of the mechanisms involved in the development of meningitis contributes to this poor outcome. Here, we demonstrate that depletion of macrophages in newborn mice renders the animals resistant to E. coli K1 induced meningitis. The entry of E. coli K1 into macrophages requires the interaction of outer membrane protein A (OmpA) of E. coli K1 with the alpha chain of Fcγ receptor I (FcγRIa, CD64) for which IgG opsonization is not necessary. Overexpression of full-length but not C-terminal truncated FcγRIa in COS-1 cells permits E. coli K1 to enter the cells. Moreover, OmpA binding to FcγRIa prevents the recruitment of the γ-chain and induces a different pattern of tyrosine phosphorylation of macrophage proteins compared to IgG2a induced phosphorylation. Of note, FcγRIa−/− mice are resistant to E. coli infection due to accelerated clearance of bacteria from circulation, which in turn was the result of increased expression of CR3 on macrophages. Reintroduction of human FcγRIa in mouse FcγRIa−/− macrophages in vitro increased bacterial survival by suppressing the expression of CR3. Adoptive transfer of wild type macrophages into FcγRIa−/− mice restored susceptibility to E. coli infection. Together, these results show that the interaction of FcγRI alpha chain with OmpA plays a key role in the development of neonatal meningitis by E. coli K1. Escherichia coli K1 is the most common cause of meningitis in premature infants; the mortality rate of this disease ranges from 5% to 30%. A better understanding of the pathogenesis of E. coli K1 meningitis is needed to develop new preventative strategies. We have shown that outer membrane protein A (OmpA) of E. coli K1, independent of antibody opsonization, is critical for bacterial entrance and survival within macrophages. Using a newborn mouse model, we found that depletion of macrophages renders the animals resistant to E. coli K1 induced meningitis. OmpA binds to α-chain of Fcγ-receptor I (FcγRIa) in macrophages, but does not induce expected gamma chain association and signaling. FcγRIa knockout mice are resistant to E. coli K1 infection because their macrophages express more CR3 and are thus able to kill bacteria with greater efficiency, preventing the development of high-grade bacteremia, a pre-requisite for the onset of meningitis. These novel observations demonstrate that inhibiting OmpA binding to FcγRIa is a promising therapeutic target for treatment or prevention of neonatal meningitis.
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MESH Headings
- Animals
- Animals, Newborn
- Bacterial Outer Membrane Proteins/metabolism
- Binding, Competitive
- Blotting, Western
- Brain/immunology
- Brain/metabolism
- Brain/microbiology
- COS Cells
- Chlorocebus aethiops
- Escherichia coli/growth & development
- Escherichia coli/pathogenicity
- Flow Cytometry
- Humans
- Immunoglobulin G/immunology
- Immunoglobulin G/metabolism
- Immunoprecipitation
- Macrophage-1 Antigen/metabolism
- Macrophages/immunology
- Macrophages/metabolism
- Macrophages/microbiology
- Meningitis, Escherichia coli/etiology
- Meningitis, Escherichia coli/metabolism
- Meningitis, Escherichia coli/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Nitric Oxide/metabolism
- Phagocytosis
- Phosphorylation
- RNA, Messenger/genetics
- Receptors, IgG/physiology
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Rahul Mittal
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Sunil K. Sukumaran
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Suresh K. Selvaraj
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - David G. Wooster
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - M. Madan Babu
- Structural Studies Division, Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Alan D. Schreiber
- Hematology and Oncology Division, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - J. Sjef Verbeek
- Department of Human Genetics, University Medical Center, Leiden, Netherlands
| | - Nemani V. Prasadarao
- Division of Infectious Diseases, The Saban Research Institute, Childrens Hospital Los Angeles, Los Angeles, California, United States of America
- Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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Heit B, Yeung T, Grinstein S. Changes in mitochondrial surface charge mediate recruitment of signaling molecules during apoptosis. Am J Physiol Cell Physiol 2010; 300:C33-41. [PMID: 20926778 DOI: 10.1152/ajpcell.00139.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Electrostatic interactions with negative lipids contribute to the subcellular localization of polycationic proteins. In situ measurements using cytosolic probes of surface charge indicate that normal mitochondria are not noticeably electronegative. However, during apoptosis mitochondria accrue negative charge and acquire the ability to attract cationic proteins, including K-Ras. The marked increase in the surface charge of mitochondria occurs early in apoptosis, preceding depolarization of their inner membrane, cytochrome c release, and flipping of phosphatidylserine across the plasmalemma. Using novel biosensors, we determined that the increased electronegativity of the mitochondria coincided with and was likely attributable to increased exposure of cardiolipin, which is dianionic. Ectopic (over)expression of cardiolipin-binding proteins precluded the increase in surface charge and inhibited apoptosis, implying that mitochondrial exposure of negatively charged lipids is required for progression of programmed cell death.
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Affiliation(s)
- Bryan Heit
- Hospital for Sick Children, Toronto, Ontario, Canada
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Tam C, Idone V, Devlin C, Fernandes MC, Flannery A, He X, Schuchman E, Tabas I, Andrews NW. Exocytosis of acid sphingomyelinase by wounded cells promotes endocytosis and plasma membrane repair. ACTA ACUST UNITED AC 2010; 189:1027-38. [PMID: 20530211 PMCID: PMC2886342 DOI: 10.1083/jcb.201003053] [Citation(s) in RCA: 258] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Rapid plasma membrane resealing is essential for cellular survival. Earlier studies showed that plasma membrane repair requires Ca(2+)-dependent exocytosis of lysosomes and a rapid form of endocytosis that removes membrane lesions. However, the functional relationship between lysosomal exocytosis and the rapid endocytosis that follows membrane injury is unknown. In this study, we show that the lysosomal enzyme acid sphingomyelinase (ASM) is released extracellularly when cells are wounded in the presence of Ca(2+). ASM-deficient cells, including human cells from Niemann-Pick type A (NPA) patients, undergo lysosomal exocytosis after wounding but are defective in injury-dependent endocytosis and plasma membrane repair. Exogenously added recombinant human ASM restores endocytosis and resealing in ASM-depleted cells, suggesting that conversion of plasma membrane sphingomyelin to ceramide by this lysosomal enzyme promotes lesion internalization. These findings reveal a molecular mechanism for restoration of plasma membrane integrity through exocytosis of lysosomes and identify defective plasma membrane repair as a possible component of the severe pathology observed in NPA patients.
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Affiliation(s)
- Christina Tam
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
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Hafeman S, London C, Elmslie R, Dow S. Evaluation of liposomal clodronate for treatment of malignant histiocytosis in dogs. Cancer Immunol Immunother 2010; 59:441-52. [PMID: 19760220 PMCID: PMC11029889 DOI: 10.1007/s00262-009-0763-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Accepted: 08/21/2009] [Indexed: 11/24/2022]
Abstract
Malignant histiocytosis (MH) is an aggressive cancer derived from myeloid lineage cells in both dogs and humans. In dogs, the tumor is characterized by the rapid development of metastatic tumors in multiple sites, including especially the lungs and lymph nodes. Humans develop an analogous disease known as Langerhans cell histiocytosis, which primarily affects children and young adults. Because these tumors are often resistant to conventional chemotherapy, there is a need for newer therapeutic approaches. Systemic administration of liposomal clodronate (LC) has been shown to effectively deplete phagocytic cells (e.g., macrophages and dendritic cells) in mice. We investigated therefore whether LC could also be used to treat naturally occurring MH in dogs. First, the susceptibility of canine MH cells to LC-mediated killing was assessed in vitro. Then the clinical safety and effectiveness of LC as a treatment for MH was assessed in a pilot study in five pet dogs with spontaneous MH. We found that canine MH cells were very susceptible to LC-induced apoptotic cell death, whereas other tumor cell lines were resistant to killing by LC. Studies using labeled liposomes demonstrated that susceptibility to LC killing was directly related to the efficiency of liposome uptake. In pet dogs with spontaneous MH, we found that a short course of LC treatment elicited significant tumor regression in two of five treated animals. These findings suggest that liposomal delivery of clodronate and possibly other bisphosphonates may offer an effective new approach to treatment of histiocytic neoplasms in dogs and humans.
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Affiliation(s)
- Scott Hafeman
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Ft. Collins, CO 80523 USA
| | - Cheryl London
- Department of Veterinary Biosciences, Ohio State University, Columbus, OH 43210 USA
| | | | - Steven Dow
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Ft. Collins, CO 80523 USA
- Department of Clinical Sciences, Animal Cancer Center, Colorado State University, Ft. Collins, CO 80523 USA
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A new homogeneous high-throughput screening assay for profiling compound activity on the human ether-a-go-go-related gene channel. Anal Biochem 2009; 394:30-8. [PMID: 19583963 DOI: 10.1016/j.ab.2009.07.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 06/27/2009] [Accepted: 07/02/2009] [Indexed: 01/08/2023]
Abstract
Long QT syndrome, either inherited or acquired from drug treatments, can result in ventricular arrhythmia (torsade de pointes) and sudden death. Human ether-a-go-go-related gene (hERG) channel inhibition by drugs is now recognized as a common reason for the acquired form of long QT syndrome. It has been reported that more than 100 known drugs inhibit the activity of the hERG channel. Since 1997, several drugs have been withdrawn from the market due to the long QT syndrome caused by hERG inhibition. Food and Drug Administration regulations now require safety data on hERG channels for investigative new drug (IND) applications. The assessment of compound activity on the hERG channel has now become an important part of the safety evaluation in the process of drug discovery. During the past decade, several in vitro assay methods have been developed and significant resources have been used to characterize hERG channel activities. However, evaluation of compound activities on hERG have not been performed for large compound collections due to technical difficulty, lack of throughput, and/or lack of biological relevance to function. Here we report a modified form of the FluxOR thallium flux assay, capable of measuring hERG activity in a homogeneous 1536-well plate format. To validate the assay, we screened a 7-point dilution series of the LOPAC 1280 library collection and reported rank order potencies of ten common hERG inhibitors. A correlation was also observed for the hERG channel activities of 10 known hERG inhibitors determined in this thallium flux assay and in the patch clamp experiment. Our findings indicate that this thallium flux assay can be used as an alternative method to profile large-volume compound libraries for compound activity on the hERG channel.
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