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Castellano M, Blanco V, Calzi ML, Costa B, Witwer K, Hill M, Cayota A, Segovia M, Tosar JP. Ribonuclease activity undermines immune sensing of naked extracellular RNA. bioRxiv 2024:2024.04.23.590771. [PMID: 38712104 PMCID: PMC11071435 DOI: 10.1101/2024.04.23.590771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The plasma membrane and the membrane of endosomal vesicles are considered physical barriers preventing extracellular RNA uptake. While naked RNA can be spontaneously internalized by certain cells types, functional delivery of naked RNA into the cytosol has been rarely observed. Here we show that extracellular ribonucleases, mainly derived from cell culture supplements, have so far hindered the study of extracellular RNA functionality. In the presence of active ribonuclease inhibitors (RI), naked bacterial RNA is pro-inflammatory when spiked in the media of dendritic cells and macrophages. In murine cells, this response mainly depends on the action of endosomal Toll-like receptors. However, we also show that naked RNA can perform endosomal escape and engage with cytosolic RNA sensors and ribosomes. For example, naked mRNAs encoding reporter proteins can be spontaneously internalized and translated by a variety of cell types, in an RI-dependent manner. In vivo, RI co-injection enhances the activation induced by naked extracellular RNA on splenic lymphocytes and myeloid-derived leukocytes. Furthermore, naked extracellular RNA is inherently pro-inflammatory in ribonuclease-poor compartments such as the peritoneal cavity. Overall, these results demonstrate that naked RNA is bioactive and does not need encapsulation inside synthetic or biological lipid vesicles for functional uptake, making a case for nonvesicular extracellular RNA-mediated intercellular communication.
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Affiliation(s)
- Mauricio Castellano
- Functional Genomics Laboratory, Institut Pasteur Montevideo, Uruguay
- Immunoregulation and Inflammation Laboratory, Institut Pasteur Montevideo, Uruguay
| | - Valentina Blanco
- Functional Genomics Laboratory, Institut Pasteur Montevideo, Uruguay
| | - Marco Li Calzi
- Functional Genomics Laboratory, Institut Pasteur Montevideo, Uruguay
| | - Bruno Costa
- Functional Genomics Laboratory, Institut Pasteur Montevideo, Uruguay
- Analytical Biochemistry Unit, School of Science, Universidad de la República, Uruguay
| | - Kenneth Witwer
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- EV Core Facility “EXCEL”, Institute for Basic Biomedical Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Richman Family Precision Medicine Center of Excellence in Alzheimer’s Disease, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Marcelo Hill
- Immunoregulation and Inflammation Laboratory, Institut Pasteur Montevideo, Uruguay
- Academic Unit of Immunobiology, School of Medicine, Universidad de la República, Uruguay
| | - Alfonso Cayota
- Functional Genomics Laboratory, Institut Pasteur Montevideo, Uruguay
- Hospital de Clínicas, Universidad de la República, Uruguay
| | - Mercedes Segovia
- Immunoregulation and Inflammation Laboratory, Institut Pasteur Montevideo, Uruguay
- Academic Unit of Immunobiology, School of Medicine, Universidad de la República, Uruguay
| | - Juan Pablo Tosar
- Functional Genomics Laboratory, Institut Pasteur Montevideo, Uruguay
- Analytical Biochemistry Unit, School of Science, Universidad de la República, Uruguay
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Gámbaro F, Li Calzi M, Fagúndez P, Costa B, Greif G, Mallick E, Lyons S, Ivanov P, Witwer K, Cayota A, Tosar JP. Stable tRNA halves can be sorted into extracellular vesicles and delivered to recipient cells in a concentration-dependent manner. RNA Biol 2019; 17:1168-1182. [PMID: 31885318 DOI: 10.1080/15476286.2019.1708548] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Extracellular vesicles (EVs) are cell-derived nanoparticles that act as natural carriers of nucleic acids between cells. They offer advantages as delivery vehicles for therapeutic nucleic acids such as small RNAs. Loading of desired nucleic acids into EVs can be achieved by electroporation or transfection once purified. An attractive alternative is to transfect cells with the desired small RNAs and harness the cellular machinery for RNA sorting into the EVs. This possibility has been less explored because cells are believed to secrete only specific RNAs. However, we hypothesized that, even in the presence of selective secretion, concentration-driven RNA sorting to EVs would still be feasible. To show this, we transfected cells with glycine 5' tRNA halves, which we have previously shown to better resist RNases. We then measured their levels in EVs and in recipient cells and found that, in contrast to unstable RNAs of random sequence, these tRNA halves were present in vesicles and in recipient cells in amounts proportional to the concentration of RNA used for transfection. Similar efficiencies were obtained with other stable oligonucleotides of random sequence. Our results demonstrate that RNA stability is a key factor needed to maintain high intracellular concentrations, a prerequisite for efficient non-selective RNA sorting to EVs and delivery to cells. Given that glycine 5' tRNA halves belong to the group of stress-induced tRNA fragments frequently detected in extracellular space and biofluids, we propose that upregulation of extracellular tRNA fragments is consequential to cellular stress and might be involved in intercellular signalling.
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Affiliation(s)
- Fabiana Gámbaro
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Molecular Virology Laboratory, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
| | - Marco Li Calzi
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay
| | - Pablo Fagúndez
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
| | - Bruno Costa
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
| | - Gonzalo Greif
- Molecular Biology Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay
| | - Emily Mallick
- Molecular and Comparative Pathobiology, and Neurology, The Johns Hopkins University School of Medicine , Baltimore, MD, USA
| | - Shawn Lyons
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston, MA, USA.,Department of Medicine, Harvard Medical School , Boston, MA, USA.,Department of Biochemistry, and The Genome Science Institute, Boston University School of Medicine , Boston, MA, USA
| | - Pavel Ivanov
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital , Boston, MA, USA.,Department of Medicine, Harvard Medical School , Boston, MA, USA.,The Broad Institute of Harvard and M.I.T ., Cambridge, MA, USA
| | - Kenneth Witwer
- Molecular and Comparative Pathobiology, and Neurology, The Johns Hopkins University School of Medicine , Baltimore, MD, USA
| | - Alfonso Cayota
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Department of Medicine, Faculty of Medicine, Universidad de la República , Montevideo, Uruguay
| | - Juan Pablo Tosar
- Functional Genomics Unit, Institut Pasteur de Montevideo , Montevideo, Uruguay.,Analytical Biochemistry Unit, Nuclear Research Center, Faculty of Science, Universidad de la República , Montevideo, Uruguay
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Canuti V, Conversano M, Calzi ML, Heymann H, Matthews MA, Ebeler SE. Headspace solid-phase microextraction-gas chromatography-mass spectrometry for profiling free volatile compounds in Cabernet Sauvignon grapes and wines. J Chromatogr A 2009; 1216:3012-22. [PMID: 19233370 DOI: 10.1016/j.chroma.2009.01.104] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 01/27/2009] [Accepted: 01/29/2009] [Indexed: 10/21/2022]
Abstract
The complex aroma of wine is derived from many sources, with grape-derived components being responsible for the varietal character. The ability to monitor grape aroma compounds would allow for better understanding of how vineyard practices and winemaking processes influence the final volatile composition of the wine. Here, we describe a procedure using GC-MS combined with headspace solid-phase microextraction (HS-SPME) for profiling the free volatile compounds in Cabernet Sauvignon grapes. Different sample preparation (SPME fiber type, extraction time, extraction temperature and dilution solvent) and GC-MS conditions were evaluated to optimize the method. For the final method, grape skins were homogenized with water and 8 ml of sample were placed in a 20 ml headspace vial with addition of NaCl; a polydimethylsiloxane SPME fiber was used for extraction at 40 degrees C for 30 min with continuous stirring. Using this method, 27 flavor compounds were monitored and used to profile the free volatile components in Cabernet Sauvignon grapes at different maturity levels. Ten compounds from the grapes, including 2-phenylethanol and beta-damascenone, were also identified in the corresponding wines. Using this procedure it is possible to follow selected volatiles through the winemaking process.
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Affiliation(s)
- Valentina Canuti
- Dipartimento di Biotecnologie Agrarie, Sezione di Tecnologie Alimentari, Firenze, Italy
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Abstract
Nox-1 from Streptococcus mutans, the bacteria which cause dental caries, was previously identified as an H2O2-forming reduced nicotinamide adenine dinucleotide (NADH) oxidase. Nox-1 is homologous with the flavoprotein component, AhpF, of Salmonella typhimurium alkyl hydroperoxide reductase. A partial open reading frame upstream of nox1, homologous with the other (peroxidase) component, ahpC, from the S. typhimurium system, was also identified. We report here the complete sequence of S. mutans ahpC. Analyses of purified AhpC together with Nox-1 have verified that these proteins act as a cysteine-based peroxidase system in S. mutans, catalyzing the NADH-dependent reduction of organic hydroperoxides or H2O2 to their respective alcohols and/or H2O. These proteins also catalyze the four-electron reduction of O2 to H2O2, clarifying the role of Nox-1 as a protective protein against oxygen toxicity. Major differences between Nox-1 and AhpF include: (i) the absolute specificity of Nox-1 for NADH; (ii) lower amounts of flavin semiquinone and a more prominent FADH2 to NAD+ charge transfer absorbance band stabilized by Nox-1; and (iii) even higher redox potentials of disulfide centers relative to flavin for Nox-1. Although Nox-1 and AhpC from S. mutans were shown to play a protective role against oxidative stress in vitro and in vivo in Escherichia coli, the lack of a significant effect on deletion of these genes from S. mutans suggests the presence of additional antioxidant proteins in these bacteria.
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Affiliation(s)
- L B Poole
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem 27157, NC, USA.
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Calzi ML, Raviolo C, Ghibaudi E, de Gioia L, Salmona M, Cazzaniga G, Kurosaki M, Terao M, Garattini E. Purification, cDNA cloning, and tissue distribution of bovine liver aldehyde oxidase. J Biol Chem 1995; 270:31037-45. [PMID: 8537361 DOI: 10.1074/jbc.270.52.31037] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Aldehyde oxidase was purified to homogeneity from bovine liver and primary structural information obtained by sequencing a series of cleavage peptides permitted the cloning of the corresponding cDNA. The cDNA is 4,630 base pairs long, and it consists of a 102-base pair 5'-untranslated region followed by a 4017-base pair coding region and a 511-base pair 3'-untranslated region. The open reading frame predicts a 1339-amino acid polypeptide with a calculated molecular weight of 147,441, which is consistent with the size of the aldehyde oxidase monomeric subunit. The aldehyde oxidase polypeptide contains consensus sequences for iron-sulfur centers and a molybdopterin binding site. The amino acid sequence deduced from the cDNA shows significant similarity with that of xanthine dehydrogenases from various sources. The primary structure of bovine aldehyde oxidase is remarkably similar (approximately 86%) to that of the translation product of a cDNA recently isolated by Wright et al. (Wright, R. M., Vaitaitis, G. M., Wilson, C. M., Repine, T. B., Terada, L. S., and Repine, J. E. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 10690-10694) and reported to represent human xanthine dehydrogenase. With the help of a monospecific antibody raised against the purified protein and the isolated cDNA, the tissue distribution of the bovine aldehyde oxidase protein and corresponding mRNA was determined. Aldehyde oxidase is expressed at high levels in liver, lung, and spleen, and, at a much lower level, in many other organs.
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Affiliation(s)
- M L Calzi
- Molecular Biology Unit, Centro Catullo e Daniela Borgomainerio, Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
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