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Abstract Several alphaherpesviruses breach the basement membrane during mucosal invasion. In the present study, the role of proteases in this process was examined. The serine protease-specific inhibitor AEBSF inhibited penetration of the basement membrane by the porcine alphaherpesvirus pseudorabies virus (PRV) by 88.1% without affecting lateral spread. Inhibitors of aspartic-, cysteine-, and metalloproteases did not inhibit viral penetration of the basement membrane. Further analysis using the Soybean Type I-S trypsin inhibitor for the serine protease subcategory of trypsin-like serine proteases resulted in a 96.9% reduction in plaque depth underneath the basement membrane. These data reveal a role of a trypsin-like serine protease in PRV penetration of the basement membrane.

Abstract In general, members of the Alphaherpesvirinae use the epithelium of the upper respiratory and/or genital tract as a preferential site for primary replication. Bovine herpesvirus type 1 (BoHV-1) may replicate at both sites and cause two major clinical entities designated as infectious bovine rhinotracheitis (IBR) and infectious pustular vulvovaginitis/balanoposthitis (IPV/IPB) in cattle. It has been hypothesized that subtype 1.1 invades preferentially the upper respiratory mucosa whereas subtype 1.2 favors replication at the peripheral genital tract. However, some studies are in contrast with this hypothesis. A thorough study of primary replication at both mucosae could elucidate whether or not different BoHV-1 subtypes show differences in mucosa tropism. We established bovine respiratory and genital organ cultures with emphasis on maintenance of tissue morphology and viability during in vitro culture. In a next step, bovine respiratory and genital mucosa explants of the same animals were inoculated with several BoHV-1 subtypes. A quantitative analysis of viral invasion in the mucosa was performed at 0 h, 24 h, 48 h and 72 h post inoculation (pi) by measuring plaque latitude and penetration depth underneath the basement membrane. All BoHV-1 subtypes exhibited a more profound invasion capacity in respiratory tissue compared to that in genital tissue at 24 h pi. However, at 24 h pi plaque latitude was found to be larger in genital tissue compared to respiratory tissue and this for all subtypes. These similar findings among the different subtypes take the edge off the belief of the existence of specific mucosa tropisms of different BoHV-1 subtypes.

Efficient data sharing is hampered by an array of organizational, ethical, behavioral, and technical challenges, slowing research progress and reducing the utility of data generated by clinical research studies on neurodegenerative diseases. There is a particular need to address differences between public and private sector environments for research and data sharing, which have varying standards, expectations, motivations, and interests. The Neuronet data sharing Working Group was set up to understand the existing barriers to data sharing in public-private partnership projects, and to provide guidance to overcome these barriers, by convening data sharing experts from diverse projects in the IMI neurodegeneration portfolio. In this policy and practice review, we outline the challenges and learnings of the WG, providing the neurodegeneration community with examples of good practices and recommendations on how to overcome obstacles to data sharing. These obstacles span organizational issues linked to the unique structure of cross-sectoral, collaborative research initiatives, to technical issues that affect the storage, structure and annotations of individual datasets. We also identify sociotechnical hurdles, such as academic recognition and reward systems that disincentivise data sharing, and legal challenges linked to heightened perceptions of data privacy risk, compounded by a lack of clear guidance on GDPR compliance mechanisms for public-private research. Focusing on real-world, neuroimaging and digital biomarker data, we highlight particular challenges and learnings for data sharing, such as data management planning, development of ethical codes of conduct, and harmonization of protocols and curation processes. Cross-cutting solutions and enablers include the principles of transparency, standardization and co-design - from open, accessible metadata catalogs that enhance findability of data, to measures that increase visibility and trust in data reuse., Competing Interests: NH is an employee of Janssen Pharmaceutica NV and owns stock in Johnson & Johnson, but no product-related aspects. LS is an employee of Janssen Pharmaceutica NV. RB was employed by Aridhia Informatics Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Bradshaw, Hughes, Vallez-Garcia, Chokoshvili, Owens, Hansen, Emmert, Maetzler, Killin, Barnes, Brookes, Visser, Hofmann-Apitius, Diaz and Steukers.)

The European Commission's Innovative Medicines Initiative (IMI) has funded many projects focusing on neurodegenerative disorders (ND) that aimed to improve the diagnosis, prevention, treatment and understanding of NDs. To facilitate collaboration across this project portfolio, the IMI funded the "NEURONET" project between March 2019 and August 2022 with the aim of connecting these projects and promoting synergies, enhancing the visibility of their findings, understanding the impact of the IMI funding and identifying research gaps that warrant more/new funding. The IMI ND portfolio currently includes 20 projects consisting of 270 partner organizations across 25 countries. The NEURONET project conducted an impact analysis to assess the scientific and socio-economic impact of the IMI ND portfolio. This was to better understand the perceived areas of impact from those directly involved in the projects. The impact analysis was conducted in two stages: an initial stage developed the scope of the project, defined the impact indicators and measures to be used. A second stage designed and administered the survey amongst partners from European Federation of Pharmaceutical Industries and Associations (EFPIA) organizations and other partners (hereafter, referred to as "non-EFPIA" organizations). Responses were analyzed according to areas of impact: organizational, economic, capacity building, collaborations and networking, individual, scientific, policy, patient, societal and public health impact. Involvement in the IMI ND projects led to organizational impact, and increased networking, collaboration and partnerships. The key perceived disadvantage to project participation was the administrative burden. These results were true for both EFPIA and non-EFPIA respondents. The impact for individual, policy, patients and public health was less clear with people reporting both high and low impact. Overall, there was broad alignment between EFPIA and non-EFPIA participants' responses apart from for awareness of project assets, as part of scientific impact, which appeared to be slightly higher among non-EFPIA respondents. These results identified clear areas of impact and those that require improvement. Areas to focus on include promoting asset awareness, establishing the impact of the IMI ND projects on research and development, ensuring meaningful patient involvement in these public-private partnership projects and reducing the administrative burden associated with participation in them., Competing Interests: CH, FS, KC, and DD were employed by the National Institute for Health and Care Excellence. CD and LK were employed by SYNAPSE Research Management Partners. AB was employed by Alzheimer Europe. LP was employed by Sanofi. LS was employed by Janssen Pharmaceuticals NV., (Copyright © 2023 Hawksworth, Salih, Cresswell, Steukers, Diaz, Killin, Pradier, Bradshaw and Dawoud.)

The IMI public-private partnership between the European Commission and the European Federation of Pharmaceutical Industries and Associations (EFPIA) was launched in 2008 with an initial budget of €2 billion. Aiming to accelerate the development of innovative medicines for areas of unmet clinical need, the IMI has committed over €380 million to projects on neurodegenerative disorders (NDD), catalyzing public-private collaborations at scale and at all stages of the R&D pipeline. Because of this vast investment, research on neurodegenerative diseases has made enormous strides in recent decades. The challenge for the future however remains to utilize this newly found knowledge and generated assets to develop better tools and novel therapeutic strategies. Here, we report the results of an integrated programme analysis of the IMI NDD portfolio, performed by the Neuronet Coordination and Support Action. Neuronet was launched by the IMI in 2019 to boost synergies and collaboration between projects in the IMI NDD portfolio, to increase the impact and visibility of research, and to facilitate interactions with related initiatives worldwide. Our analysis assessed the characteristics, structure and assets of the project portfolio and identifies lessons from projects spanning preclinical research to applied clinical studies and beyond. Evaluation of project parameters and network analyses of project partners revealed a complex web of 236 partnering organizations, with EFPIA partners often acting as connecting nodes across projects, and with a great diversity of academic institutions. Organizations in the UK, Germany, France and the Netherlands were highly represented in the portfolio, which has a strong focus on clinical research in Alzheimer's and Parkinson's disease in particular. Based on surveys and unstructured interviews with NDD research leaders, we identified actions to enhance collaboration between project partners, by improving the structure and definition of in-kind contributions; reducing administrative burdens; and enhancing the exploitation of outcomes from research investments by EU taxpayers and EFPIA. These recommendations could help increase the efficiency and impact of future public-private partnerships on neurodegeneration., Competing Interests: Authors NC-P, LK, and CD were employed by SYNAPSE Research Management Partners. Author LP was employed by Sanofi. Author LS was employed by Janssen Pharmaceutica NV. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 O'Rourke, Coll-Padrós, Bradshaw, Killin, Pradier, Georges, Dawoud, Steukers and Diaz.)

Bovine herpesvirus 1 (BHV-1) infection may lead to conjunctivitis, upper respiratory tract problems, pneumonia, genital disorders and abortion. BHV-1 is able to spread quickly in a plaque-wise manner and invade by breaching the basement membrane (BM) barrier in the respiratory mucosa. BHV-1 Us3, a serine/threonine kinase, induces a dramatic cytoskeletal reorganization and BHV-1 Us9, a tail-anchored membrane protein, is required for axonal transport of viruses in neurons. In this study, we investigated the role of Us3 and Us9 during BHV-1 infection in the respiratory mucosa. First, we constructed and characterized BHV-1 Us3 null, Us9 null and revertant viruses. Then, we analysed the viral replication and plaque size (latitude) in Madin-Darby bovine kidney (MDBK) cells and the respiratory mucosa as well as viral penetration depth underneath the BM of the respiratory mucosa when inoculated with these recombinant viruses. Knockout of Us3 resulted in a 1 log 10 reduction in viral titre and plaque size (latitude) in MDBK cells and the trachea mucosa. There were no defects in the cell-to-cell spread observed for BHV-1 Us9 null virus. Both BHV-1 Us3 null and Us9 null viruses showed a significant reduction of plaque penetration underneath the BM; however, penetration was not completely inhibited. In conclusion, the current findings demonstrated that Us3 and Us9 play an important role in the invasion of BHV-1 through the BM of the respiratory mucosa, which shows the way forward for research-based attenuation of viruses in order to make safer and better-performing vaccines.

Swine influenza virus (SIV) has a strong tropism for pig respiratory mucosa, which consists of a mucus layer, epithelium, basement membrane and lamina propria. Sialic acids present on the epithelial surface have long been considered to be determinants of influenza virus tropism. However, mucus which is also rich in sialic acids may serve as the first barrier of selection. It was investigated how influenza virus interacts with the mucus to infect epithelial cells. Two techniques were applied to track SIV H1N1 in porcine mucus. The microscopic diffusion of SIV particles in the mucus was analyzed by single particle tracking (SPT), and the macroscopic penetration of SIV through mucus was studied by a virus in-capsule-mucus penetration system, followed by visualizing the translocation of the virions with time by immunofluorescence staining. Furthermore, the effects of neuraminidase on SIV getting through or binding to the mucus were studied by using zanamivir, a neuraminidase inhibitor (NAI), and Arthrobacter ureafaciens neuraminidase. The distribution of the diffusion coefficient shows that 70% of SIV particles were entrapped, while the rest diffused freely in the mucus. Additionally, SIV penetrated the porcine mucus with time, reaching a depth of 65 µm at 30 min post virus addition, 2 fold of that at 2 min. Both the microscopic diffusion and macroscopic penetration were largely diminished by NAI, while were clearly increased by the effect of exogenous neuraminidase. Moreover, the exogenous neuraminidase sufficiently prevented the binding of SIV to mucus which was reversely enhanced by effect of NAI. These findings clearly show that the neuraminidase helps SIV move through the mucus, which is important for the virus to reach and infect epithelial cells and eventually become shed into the lumen of the respiratory tract.

We developed and morphologically characterized a human genital mucosa explant model (endocervix and ectocervix/vagina) to mimic genital herpes infections caused by herpes simplex virus types 1 (HSV-1) and 2 (HSV-2). Subsequent analysis of HSV entry receptor expression throughout the menstrual cycle in genital tissues was performed, and the evolution of HSV-1/-2 mucosal spread over time was assessed. Nectin-1 and -2 were expressed in all tissues during the entire menstrual cycle. Herpesvirus entry mediator expression was limited mainly to some connective tissue cells. Both HSV-1 and HSV-2 exhibited a plaque-wise mucosal spread across the basement membrane and induced prominent epithelial syncytia., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Avian infectious laryngotracheitis virus (ILTV) is an alphaherpesvirus of poultry that is spread worldwide. ILTV enters its host via the respiratory tract and the eyes. Although ILTV has been known for a long time, the replication characteristics of the virus in the respiratory and conjunctival mucosa are still poorly studied. To study these characteristics, two in vitro explant models were developed. Light microscopy and fluorescent terminal deoxynucleotidyl transferase dUTP nick end-labelling staining were used to evaluate the viability of mucosal explants, which were found to be viable up to the end of the experiment at 96 h of cultivation. The tracheal and conjunctival mucosal explants were inoculated with ILTV and collected at 0, 24, 48 and 72 h post inoculation (p.i.). ILTV spread in a plaque-wise manner in both mucosae. A reproducible quantitative analysis of this mucosal spread was evaluated by measuring plaque numbers, plaque latitude and invasion depth underneath the basement membrane. No major differences in plaque numbers were observed over time. Plaque latitude progressively increased to 70.4 ± 12.9 μm in the trachea and 97.8 ± 9.5 μm in the conjunctiva at 72 h p.i. The virus had difficulty crossing the basement membrane and was first observed only at 48 h p.i. The virus was observed at 72 h p.i. in 56% (trachea) and 74% (conjunctiva) of the plaques. Viability analysis of infected explants indicated that ILTV blocks apoptosis in infected cells of both mucosae but activates apoptosis in bystander cells.

Equine viral arteritis (EVA) is an infectious disease with variable clinical outcome. Outbreaks, causing important economic losses, are becoming more frequent. Currently, there is a shortage of pathogenesis studies performed with European strains. In the present study, eight seronegative ponies were experimentally inoculated with the Belgian strain of equine arteritis virus (EAV) 08P178 (EU-1 clade) and monitored daily for clinical signs of EVA. Nasopharyngeal swabs, ocular swabs, bronchoalveolar cells and blood were collected for virological and serological testing. Two ponies were euthanized at 3, 7, 14, and 28 days post infection (DPI). After necropsy, specimens were collected for virus titration and immunofluorescence. EVA symptoms such as fever and lymphadenomegaly were evident from 3 to 10 DPI. Virus was isolated in nasal secretions from 2 to 9 DPI and in bronchoalveolar cells from 3 to 7 DPI. A cell-associated viraemia was detected from 3 to 10 DPI. After replication in the respiratory tract and draining lymph nodes, EAV reached secondary target organs (high virus titers in internal organs sampled at 7 DPI). At 14 DPI, virus titers dropped drastically and, at 28 DPI, only tonsils were positive. Immunofluorescence revealed both individual and clustered EAV-infected cells. Antibodies were detected starting from 7 DPI. It can be concluded that the Belgian strain 08P178 is a European mildly virulent subtype. At present, most European EAV strain infections were thought to run a subclinical course. This study is a proof that mildly virulent European EAV strains do exist in the field., (Copyright © 2012 Elsevier B.V. All rights reserved.)

During primary contact with susceptible hosts, microorganisms face an array of barriers that thwart their invasion process. Passage through the basement membrane (BM), a 50-100-nm-thick crucial barrier underlying epithelia and endothelia, is a prerequisite for successful host invasion. Such passage allows pathogens to reach nerve endings or blood vessels in the stroma and to facilitate spread to internal organs. During evolution, several pathogens have developed different mechanisms to cross this dense matrix of sheet-like proteins. To breach the BM, some microorganisms have developed independent mechanisms, others hijack host cells that are able to transverse the BM (e.g. leukocytes and dendritic cells) and oncogenic microorganisms might even trigger metastatic processes in epithelial cells to penetrate the underlying BM., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Equine herpesvirus 1 (EHV1) is a ubiquitous equine alphaherpesvirus that causes respiratory disease, neurological symptoms and abortions. Current vaccines are not fully protective and effective therapeutics are lacking. A-5021 [(1'S,2'R)-9-[[1',2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guanine], previously shown to possess potent anti-herpetic activity against most human herpesviruses, was evaluated for its potential to inhibit EHV1 replication. In equine embryonic lung (EEL) cells, infected with either a non-neurovirulent (97P70) or a neurovirulent (03P37) EHV1 isolate, A-5021 proved to be about 15-fold more potent than acyclovir in inhibiting viral replication. Moreover, in equine nasal mucosal explants, A-5021 (at 8 and 32μM) was able to completely inhibit viral plaque formation whereas acyclovir did not exert an antiviral effect at these concentrations. Our data demonstrate that A-5021 is a potent inhibitor of EHV1 replication and may have potential for the treatment and/or prophylaxis of infections with this virus., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Pseudorabies virus (PRV) initially replicates in the porcine upper respiratory tract. It easily invades the mucosae and submucosae for subsequent spread throughout the body via blood vessels and nervous system. In this context, PRV developed ingenious processes to overcome different barriers such as epithelial cells and the basement membrane. Another important but often overlooked barrier is the substantial mucus layer which coats the mucosae. However, little is known about how PRV particles interact with porcine respiratory mucus. We therefore measured the barrier properties of porcine tracheal respiratory mucus, and investigated the mobility of nanoparticles including PRV in this mucus. We developed an in vitro model utilizing single particle tracking microscopy. Firstly, the mucus pore size was evaluated with polyethylene glycol coupled (PEGylated) nanoparticles and atomic force microscope. Secondly, the mobility of PRV in porcine tracheal respiratory mucus was examined and compared with that of negative, positive and PEGylated nanoparticles. The pore size of porcine tracheal respiratory mucus ranged from 80 to 1500 nm, with an average diameter of 455±240 nm. PRV (zeta potential: -31.8±1.5 mV) experienced a severe obstruction in porcine tracheal respiratory mucus, diffusing 59-fold more slowly than in water. Similarly, the highly negatively (-49.8±0.6 mV) and positively (36.7±1.1 mV) charged nanoparticles were significantly trapped. In contrast, the nearly neutral, hydrophilic PEGylated nanoparticles (-9.6±0.8 mV) diffused rapidly, with the majority of particles moving 50-fold faster than PRV. The mobility of the particles measured was found to be related but not correlated to their surface charge. Furthermore, PEGylated PRV (-13.8±0.9 mV) was observed to diffuse 13-fold faster than native PRV. These findings clearly show that the mobility of PRV was significantly hindered in porcine tracheal respiratory mucus, and that the obstruction of PRV was due to complex mucoadhesive interactions including charge interactions rather than size exclusion.

Background: Herpes simplex virus infections are highly prevalent in humans. However, the current therapeutics suffer important drawbacks such as limited results in neonates, increasing occurrence of resistance and impeded treatment of stromal infections. Remarkably, interactions of herpesviruses with human mucosa, the locus of infection, remain poorly understood and the underlying mechanisms in stromal infection remain controversial., Methodology/principal Findings: A human model consisting of nasal respiratory mucosa explants was characterised. Viability and integrity were examined during 96 h of cultivation. HSV1-mucosa interactions were analysed. In particular, we investigated whether HSV1 is able to reach the stroma. Explant viability and integrity remained preserved. HSV1 induced rounding up and loosening of epithelial cells with very few apoptotic and necrotic cells observed. Following 16-24 h of infection, HSV1 penetrated the basement membrane and replicated in the underlying lamina propria., Conclusions/significance: This human explant model can be used to study virus-mucosa interactions and viral mucosal invasion mechanisms. Using this model, our results provide a novel insight into the HSV1 stromal invasion mechanism and for the first time directly demonstrate that HSV1 can penetrate the basement membrane.