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Espinosa LA, Ramos Y, Andújar I, Torres EO, Cabrera G, Martín A, Roche D, Chinea G, Becquet M, González I, Canaán-Haden C, Nelson E, Rojas G, Pérez-Massón B, Pérez-Martínez D, Boggiano T, Palacio J, Lozada Chang SL, Hernández L, de la Luz Hernández KR, Markku S, Vitikainen M, Valdés-Balbín Y, Santana-Medero D, Rivera DG, Vérez-Bencomo V, Emalfarb M, Tchelet R, Guillén G, Limonta M, Pimentel E, Ayala M, Besada V, González LJ. In-solution buffer-free digestion allows full-sequence coverage and complete characterization of post-translational modifications of the receptor-binding domain of SARS-CoV-2 in a single ESI-MS spectrum. Anal Bioanal Chem 2021; 413:7559-7585. [PMID: 34739558 PMCID: PMC8569510 DOI: 10.1007/s00216-021-03721-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/16/2021] [Accepted: 10/05/2021] [Indexed: 11/04/2022]
Abstract
Subunit vaccines based on the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 provide one of the most promising strategies to fight the COVID-19 pandemic. The detailed characterization of the protein primary structure by mass spectrometry (MS) is mandatory, as described in ICHQ6B guidelines. In this work, several recombinant RBD proteins produced in five expression systems were characterized using a non-conventional protocol known as in-solution buffer-free digestion (BFD). In a single ESI-MS spectrum, BFD allowed very high sequence coverage (≥ 99%) and the detection of highly hydrophilic regions, including very short and hydrophilic peptides (2-8 amino acids), and the His6-tagged C-terminal peptide carrying several post-translational modifications at Cys538 such as cysteinylation, homocysteinylation, glutathionylation, truncated glutathionylation, and cyanylation, among others. The analysis using the conventional digestion protocol allowed lower sequence coverage (80-90%) and did not detect peptides carrying most of the above-mentioned PTMs. The two C-terminal peptides of a dimer [RBD(319-541)-(His)6]2 linked by an intermolecular disulfide bond (Cys538-Cys538) with twelve histidine residues were only detected by BFD. This protocol allows the detection of the four disulfide bonds present in the native RBD, low-abundance scrambling variants, free cysteine residues, O-glycoforms, and incomplete processing of the N-terminal end, if present. Artifacts generated by the in-solution BFD protocol were also characterized. BFD can be easily implemented; it has been applied to the characterization of the active pharmaceutical ingredient of two RBD-based vaccines, and we foresee that it can be also helpful to the characterization of mutated RBDs.
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Affiliation(s)
- Luis Ariel Espinosa
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Yassel Ramos
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Ivan Andújar
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Enso Onill Torres
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Gleysin Cabrera
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Alejandro Martín
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Diamilé Roche
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Glay Chinea
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Mónica Becquet
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Isabel González
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Camila Canaán-Haden
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Elías Nelson
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Gertrudis Rojas
- Center of Molecular Immunology, 216 St., P.O. Box 16040, Havana, Cuba
| | | | | | - Tamy Boggiano
- Center of Molecular Immunology, 216 St., P.O. Box 16040, Havana, Cuba
| | - Julio Palacio
- Center of Molecular Immunology, 216 St., P.O. Box 16040, Havana, Cuba
| | | | - Lourdes Hernández
- Center of Molecular Immunology, 216 St., P.O. Box 16040, Havana, Cuba
| | | | - Saloheimo Markku
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 VTT, Espoo, Finland
| | - Marika Vitikainen
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044 VTT, Espoo, Finland
| | | | | | - Daniel G Rivera
- Laboratory of Synthetic and Biomolecular Chemistry, Faculty of Chemistry, University of Havana, Zapata & G, 10400, Havana, Cuba
| | | | - Mark Emalfarb
- Dyadic International, Inc, 140 Intercoastal Pointe Drive, Suite #404, Jupiter, FL, 33477, USA
| | - Ronen Tchelet
- Dyadic International, Inc, 140 Intercoastal Pointe Drive, Suite #404, Jupiter, FL, 33477, USA
| | - Gerardo Guillén
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Miladys Limonta
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Eulogio Pimentel
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Marta Ayala
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Vladimir Besada
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba
| | - Luis Javier González
- Center for Genetic Engineering and Biotechnology, Ave 31, e/ 158 y 190, Cubanacán, Playa, Havana, Cuba.
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Carmenate T, Ortíz Y, Enamorado M, García-Martínez K, Avellanet J, Moreno E, Graça L, León K. Blocking IL-2 Signal In Vivo with an IL-2 Antagonist Reduces Tumor Growth through the Control of Regulatory T Cells. THE JOURNAL OF IMMUNOLOGY 2018; 200:3475-3484. [PMID: 29618524 DOI: 10.4049/jimmunol.1700433] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 03/13/2018] [Indexed: 01/06/2023]
Abstract
IL-2 is critical for peripheral tolerance mediated by regulatory T (Treg) cells, which represent an obstacle for effective cancer immunotherapy. Although IL-2 is important for effector (E) T cell function, it has been hypothesized that therapies blocking IL-2 signals weaken Treg cell activity, promoting immune responses. This hypothesis has been partially tested using anti-IL-2 or anti-IL-2R Abs with antitumor effects that cannot be exclusively attributed to lack of IL-2 signaling in vivo. In this work, we pursued an alternative strategy to block IL-2 signaling in vivo, taking advantage of the trimeric structure of the IL-2R. We designed an IL-2 mutant that conserves the capacity to bind to the αβ-chains of the IL-2R but not to the γc-chain, thus having a reduced signaling capacity. We show our IL-2 mutein inhibits IL-2 Treg cell-dependent differentiation and expansion. Moreover, treatment with IL-2 mutein reduces Treg cell numbers and impairs tumor growth in mice. A mathematical model was used to better understand the effect of the mutein on Treg and E T cells, suggesting suitable strategies to improve its design. Our results show that it is enough to transiently inhibit IL-2 signaling to bias E and Treg cell balance in vivo toward immunity.
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Affiliation(s)
| | - Yaquelín Ortíz
- Centro de Inmunología Molecular, 16040 Havana, Cuba; and
| | | | | | | | - Ernesto Moreno
- Centro de Inmunología Molecular, 16040 Havana, Cuba; and
| | - Luis Graça
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Kalet León
- Centro de Inmunología Molecular, 16040 Havana, Cuba; and
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Shao G, Qian D, Wang H, Yan Z, Hu M, Wang T, Wang B. Construction of the plasmid coding for the expression of the EGFP- M-IL-2( 88Arg, 125Ala) fusion protein and the anti-tumor effects exerted by the fusion protein in HeLa-60 cells. Oncol Lett 2015; 9:2729-2735. [PMID: 26137137 DOI: 10.3892/ol.2015.3125] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 03/11/2015] [Indexed: 11/05/2022] Open
Abstract
Gene therapy is a promising therapeutic option for the treatment of various cancers, and tumor-targeted plasmids encoding toxic protein genes are potential tools for gene therapy. In the present study, a recombinant plasmid containing the genes for the toxic protein melittin and interleukin-2 (IL-2) was constructed. Melittin and IL-2 are known to play key roles in immunoregulation and cancer therapy, but they each possess defects that limit the clinical application of these proteins. The present study aimed to construct a novel recombinant expression plasmid, pLEGFP-C1-M-IL-2(88Arg, 125Ala), and to improve the biological activity of IL-2 and melittin. The M-IL-2(88Arg, 125Ala) gene was excised from the pPICZαA/M-IL-2(88Arg, 125Ala) plasmid by polymerase chain reaction (PCR). The pLEGFP-C1 plasmid carrying the enhanced green fluorescent protein (EGFP) gene was used as a shuttle plasmid. Subsequent to digestion, the M-IL-2(88Arg, 125Ala) gene was subcloned into the pLEGFP-C1 vector to build the pLEGFP-C1-M-IL-2(88Arg, 125Ala) eukaryotic expression plasmid, which was identified by restriction enzyme digestion and gene sequencing. Confocal microscopy was used to determine the transfection efficiency subsequent to the plasmid being transfected into the cervical cancer HeLa cell line. The cells transfected with the pLEGFP-C1-M-IL-2(88Arg, 125Ala) plasmid demonstrated a decreased transfection efficiency compared with the cells transfected with the pLEGFP-C1 plasmid. The cellular expression of M-IL-2(88Arg, 125Ala) was detected by reverse transcription PCR and western blot analysis. Finally, cell counting kit-8 and apoptosis assays were performed to investigate the effects of the expression of the M-IL-2(88Arg, 125Ala) fusion protein on HeLa cells and to analyze the antitumor activity of the protein. In conclusion, a recombinant eukaryotic pLEGFP-C1-M-IL-2(88Arg, 125Ala) expression plasmid containing the M-IL-2(88Arg, 125Ala) fusion gene was constructed and the M-IL-2(88Arg, 125Ala) fusion protein was successfully expressed in HeLa cells. Furthermore, the M-IL-2(88Arg, 125Ala) fusion protein was able to inhibit HeLa cell proliferation and induce apoptosis in the tumor cells. These findings may offer an alternative method for anticancer therapy. The present study has provided a basis for future studies into the M-IL-2(88Arg, 125Ala) fusion gene.
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Affiliation(s)
- Guangcan Shao
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Dongmeng Qian
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Haitao Wang
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Zhiyong Yan
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Ming Hu
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Tongmei Wang
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Bin Wang
- Department of Microbiology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
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