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Abstract: Human papillomavirus (HPV) infection poses a significant health challenge, particularly in low- and middle-income countries (LMIC), where limited healthcare access and awareness hinder vaccine accessibility. To identify alternative HPV targeting interventions, we previously reported on surfactant protein A (SP-A) as a novel molecule capable of recognising HPV16 pseudovirions (HPV16-PsVs) and reducing infection in a murine cervicovaginal HPV challenge model. Building on these findings, our current study aimed to assess SP-A’s suitability as a broad-spectrum HPV-targeting molecule and its impact on innate immune responses. We demonstrate SP-A’s ability to agglutinate and opsonise multiple oncogenic HPV-PsVs types, enhancing their uptake and clearance by RAW264.7 murine macrophages and THP-1 human-derived immune cells. The SP-A opsonisation of HPV not only led to increased lysosomal accumulation in macrophages and HaCaT keratinocytes but also resulted in a decreased infection of HaCaT cells, which was further decreased when co-cultured with innate immune cells. An analysis of human innate immune cell cytokine profiles revealed a significant inflammatory response upon SP-A exposure, potentially contributing to the overall inhibition of HPV infection. These results highlight the multi-layered impact of SP-A on HPV, innate immune cells and keratinocytes and lay the basis for the development of alternative prophylactic interventions against diverse HPV types.
Keywords: surfactant protein A, SP-A, human papillomavirus, HPV, pseudovirus, cervical cancer, HPV prophylactic, low- and middle-income countries, LMIC
Published in RUNG: 22.07.2024; Views: 167; Downloads: 3
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Abstract: Background. Protein complexes provide valuable biological information but can be difficult to handle [1]. Therefore, technical advancements designed to improve their manipulation are al-ways useful. Methods. We investigated the opportunity to exploit native agarose gels and the contact bot method for the transfer of native proteins to membranes as means for optimizing the conditions for obtaining stable complexes [2]. As a simple model of protein-protein interactions, an anti-gen-ligand complex was used in which both proteins were fused to reporters. Results. At each step, it was possible to visualize both the antigen, fused to a fluorescent pro-tein, and the ligand, fused to a monomeric ascorbate peroxidase (APEX) and, as such, a way to tune the protocol. The conditions for the complex formation were adapted by modifying the buffer conditions, the concentration of the proteins and of the cross-linkers. Conclusions. The procedure is rapid, inexpensive, and the several detection opportunities al-lows for both the monitoring of complex stability and the preservation of the functionality of its components, which is critical for understanding their biomedical implications and supporting drug discovery. The overall protocol represents a handy alternative to gel filtration, uses very standard and ubiquitous equipment, and can be implemented rapidly and without specific train-ing. References: [1] O. Puig, F. Caspary, G. Rigaut, B. Rutz, E. Bouveret, E. Bragado-Nilsson, M. Wilm, B. Séraphin. The tandem affinity purification (TAP) method: a general procedure of protein complex purification. Methods. (San Diego, Calif.), 24(3), 218–229 [2] C. Sakuma, M. Nakagawa, Y. Tomioka, T. Maruyama, K. Entzminger, J.K. Fleming, T. Shibata, Y. Kurosawa, C.J. Okumura, T. Arakawa, T. Akuta. Western blotting of native proteins from agarose gels. Biotechniques. 2022 May;72(5):207-218
Keywords: protein complexes, contact blotting, native agarose gels, protein interaction
Published in RUNG: 17.06.2024; Views: 348; Downloads: 0
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Abstract: Forest environments are exposed to multiple stressful factors of both abiotic and biotic nature which may lead to their massive decline [1]. Understanding the molecular mechanisms of specific stress conditions and monitoring the fluctuations of reliable forest plant biomarkers with affordable methods would be instrumental for assessing stress levels over the time. Ascorbate peroxidase (APX) represents a suitable plant biomarker. APX is a hydrogen peroxide-scavenging enzyme the critical role of which has been described in several plants, both herbaceous and woody. Its activity generally increases under oxidative stress during which its peroxide detoxifying function is part of the wider ascorbate-glutathione cycle [2]. The development of reagents to detect such fluctuations would help the evaluation of plant physiological conditions. In this study, nanobodies (Nbs) targeting APX have been identified. Nbs correspond to the variable domain of heavy chain-only antibodies derived from camelids. They are small (15 kDa), stable, and can be easily produced in bacteria fused to different protein tags according to the downstream applications [3]. After their isolation by biopanning against soluble APX, they have been produced and underwent a biophysical characterization in combination with their antigen (APX-Nb complex) to identify the best binders in terms of stability and affinity. The protein complex characterization was supported by Instruct-ERIC and mainly performed at the BIOCEV institute of Prague. Data from Mass Photometry and Dynamic Light scattering evidenced the formation of the protein complexes, whereas the preliminary data of Hydrogen-Deuterium Exchange Mass Spectrometry, performed with the aim of identifying the residues involved in the paratope/epitope interface, were insufficient to clarify the issue and rather suggested that the interaction has low affinity. This indication was then confirmed by ELISA assay. The combination of multiple methods allowed a comprehensive sample characterization which will require further structural analyses to provide a complete picture of the APX-Nb complex. [1] G. Marie. B. C. M. B. C. Walters, “Forest decline and tree mortality in a southeastern Ohio oak-hickory forest,” Ohio Journal of Science , vol. 97, 1997. [2] O. Chew, J. Whelan, and A. H. Millar, “Molecular Definition of the Ascorbate-Glutathione Cycle in Arabidopsis Mitochondria Reveals Dual Targeting of Antioxidant Defenses in Plants,” Journal of Biological Chemistry, vol. 278, no. 47, 2003, doi: 10.1074/jbc.M307525200. [3] S. Muyldermans, “A guide to: generation and design of nanobodies,” FEBS J, vol. 288, no. 7, pp. 2084–2102, Apr. 2021, doi: 10.1111/febs.15515.
Keywords: nanobody, ascorbate peroxidase, plant stress, protein complex, biophysical methodologies
Published in RUNG: 31.05.2024; Views: 545; Downloads: 0
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Keywords: fluorescent proteins, protein stability, protein degradation
Published in RUNG: 16.05.2024; Views: 453; Downloads: 2
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Keywords: recombinant protein, protein quality control, protein aggregates
Published in RUNG: 02.11.2023; Views: 1167; Downloads: 0
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