title: Mastomys coucha as preclinical model to study macrophage-assisted DNA repair and cross-protecting L2 based vaccination in the same animal
creator: Ahmels, Melinda
description: Non-melanoma skin cancer (NMSC) is the most commonly diagnosed skin cancer in Caucasians and develops at UV-exposed areas of the body. Particularly the development of SCCs is favoured by infection with human papillomaviruses (HPVs). HPVs have been shown to alter the immune response to prevent apoptosis of infected cells. L1-VLP-based vaccines have already been licensed to protect against high-risk HPVs, but these are limited in their cross-protection against cutaneous types. To study the impact of PV infections on both innate and adaptive immunity in detail, an immunocompetent animal model is required. Mastomys coucha represents such a natural preclinical model to study the development of NMSC. After infection with the species-specific Mastomys natalensis papillomavirus (MnPV) the animals develop benign skin tumours. During chronic UV exposure, MnPV-infected Mastomys develop SCCs in which Trp53 was found to be frequently mutated, potentially influencing DNA repair mechanisms after UVB irradiation. It has been reported that macrophages are able to increase DNA repair efficiency by secreting HB-EGF (heparin-binding epidermal growth factor-like growth factor). Based on these results, the innate immune system and its influence on DNA repair mechanisms after UV irradiation were investigated in the present study. Indeed, HB-EGF was shown to increase DNA repair efficiency in Mastomys fibroblasts, independent of the Trp53 status. In addition, the oncogene MnPV E7 was observed to upregulate the expression of the cytokine MCP-1 (monocyte chemoattractant protein-1) after UV irradiation, suggesting that macrophage migration and activation may be stimulated. MnPV E7 further increases expression of pro-inflammatory cytokines after UV irradiation, which resembles a chronic inflammation in persistent infection. To investigate which signalling pathways are regulated after irradiation and HB-EGF treatment, proteomic analyses were performed. The molecular changes after 24 hours were limited, suggesting that the proteins responsible for the morphologically detectable effects had already returned to their normal levels. However, the upregulation of matrix metalloproteinase-3 (MMP-3) by stimulating the MAPK/ERK-signalling pathway was observed in p53-deficient cells. This protein, which is able to cleave the preform of HB-EGF, could lead to a positive feedback loop. In the second part of this thesis, the two HPV L2-based vaccines (HPV16 RG1-VLP and CUT-PANHPVAX) were tested in Mastomys coucha for their cross-protection against MnPV, in comparison to a mock control or MnPV L1-VLPs. Both L2-based vaccines provided protection in vivo, as the viral load in hair bulbs of vaccinated animals was lower compared to those of unprotected animals. In addition, cross-reactive antibodies against MnPV L2 could be detected for both vaccines, which also had a cross-neutralising effect against MnPV pseudoviruses in vitro. This study proves that next-generation L2-based vaccines are able to protect against PV infections even for different genera.
date: 2023
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserverhttps://archiv.ub.uni-heidelberg.de/volltextserver/33354/1/Thesis_M.Ahmels.pdf
identifier: DOI:10.11588/heidok.00033354
identifier: urn:nbn:de:bsz:16-heidok-333544
identifier:   Ahmels, Melinda  (2023) Mastomys coucha as preclinical model to study macrophage-assisted DNA repair and cross-protecting L2 based vaccination in the same animal.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/33354/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng