Search Results (19)

Respiratory viruses are among the most common causes of human infections. Examining pathological processes linked to respiratory viral infections is essential for diagnosis, treatment strategies, and developing novel therapeutics. Alterations in oxidative stress levels and homeostasis are significant processes associated with respiratory viral infections. The study aimed to compare selected oxidative stress markers: total oxidative status (TOS), total antioxidant capacity (TAC), and the oxidative stress index (OSI) levels and glutathione peroxidase (GPx) and glutathione reductase (GR) activities in normal (MRC5 cell line) and tumor (A549 cell line) lung cells infected with human coronaviruses (HCoV) OC43 and 229E, human adenovirus type 5 (HAdV5), or human rhinovirus A (HRV A). We observed that a respiratory viral infection more significantly affected non-enzymatic oxidative stress markers in a lung adenocarcinoma model (A549 cells), while human lung fibroblasts (MRC-5 cell line) presented changes in enzymatic and non-enzymatic oxidative stress markers. We suggest that further detailed research is required to analyze this phenomenon. Full article

Human adenovirus (HAdV) is a common pathogen, which can lead to various clinical symptoms and—in some cases—central nervous system (CNS) dysfunctions, such as encephalitis and meningitis. Although the initial events of virus entry have already been identified in various cell types, the mechanism of neuronal uptake of adenoviruses is relatively little understood. The aim of this study was to investigate early events during adenoviral infection, in particular to determine the connection between cellular coxsackievirus and adenovirus receptor (CAR), clathrin, caveolin, and early endosomal proteins (EEA1 and Rab5) with the entry of HAdVs into primary murine neurons in vitro. An immunofluorescence assay and confocal microscopy analysis were carried out to determine HAdV4, 5, and 7 correlation with CAR, clathrin, caveolin, and early endosomal proteins in neurons. The quantification of Pearson’s coefficient between CAR and HAdVs indicated that the HAdV4 and HAdV5 types correlated with CAR and that the correlation was more substantial for HAdV5. Inhibition of clathrin-mediated endocytosis using chlorpromazine limited the infection with HAdV, whereas inhibition of caveolin-mediated endocytosis did not affect virus entry. Thus, the entry of tested HAdV types into neurons was most likely associated with clathrin but not caveolin. It was also demonstrated that HAdVs correlate with the Rab proteins (EEA1, Rab5) present in early vesicles, and the observed differences in the manner of correlation depended on the serotype of the virus. With our research, we strove to expand knowledge regarding the mechanism of HAdV entry into neurons, which may be beneficial for developing potential therapeutics in the future. Full article

Propolis is a natural mixture of resins, wax, and pollen from plant buds and flowers, enriched with enzymes and bee saliva. It also contains various essential oils, vitamins, mineral salts, trace elements, hormones, and ferments. It has been found that propolis possesses antimicrobial, antiviral, and anti-inflammatory properties. We have studied the antiviral activity of six extracts of Bulgarian propolis collected from six districts of Bulgaria. The study was conducted against structurally different viruses: human coronavirus strain OC-43 (HCoV OC-43) and human respiratory syncytial virus type 2 (HRSV-2) (enveloped RNA viruses), human herpes simplex virus type 1 (HSV-1) (enveloped DNA virus), human rhinovirus type 14 (HRV-14) (non-enveloped RNA virus) and human adenovirus type 5 (HadV-5) (non-enveloped DNA virus). The influence of the extracts on the internal replicative cycle of viruses was determined using the cytopathic effect (CPE) inhibition test. The virucidal activity, its impact on the stage of viral adsorption to the host cell, and its protective effect on healthy cells were evaluated using the final dilution method, making them the focal points of interest. The change in viral infectivity under the action of propolis extracts was compared with untreated controls, and Δlgs were determined. Most propolis samples administered during the viral replicative cycle demonstrated the strongest activity against HCoV OC-43 replication. The influence of propolis extracts on the viability of extracellular virions was expressed to a different degree in the various viruses studied, and the effect was significantly stronger in those with an envelope. Almost all extracts significantly inhibited the adsorption step of the herpes virus and, to a less extent, of the coronavirus to the host cell, and some of them applied before viral infection demonstrated a protective effect on healthy cells. Our results enlarge the knowledge about the action of propolis and could open new perspectives for its application in viral infection treatment. Full article

Chitosan is a natural biopolymer with a proven ability to impart textile materials with antimicrobial properties when loaded onto them. The mechanism of its bacteriological activity depends on the contact between the positive and negative charges of the amino groups located on the surface of the microbes. Unfortunately, the type of microorganisms and pH influence this action–shortcomings that can be avoided by chitosan modification and by loading its film with substances possessing antimicrobial properties. In this study, chitosan was modified with benzaldehyde and crosslinked with glutaraldehyde to form a film on the surface of cotton fabric (CB). Also, another material was obtained by including zinc oxide particles (CBZ) synthesized in situ into the chitosan coating. The performed analyses (contact angle measurement, optical and scanning electron microscopy, FTIR, XRD, and thermal analysis) evidenced the modification of the cotton fabric and the alteration of the film properties after zinc oxide inclusion. A comparison of the antimicrobial properties of the new CB with materials prepared with chitosan without benzaldehyde from our previous study verified the influence of the hydrophobicity and surface roughness of the fabric surface on the enhancement of antimicrobial activity. The microbial growth inhibition increased in the following order: fungal strain Candida lipolytica >Gram-positive bacteria Bacillus cereus >Gram-negative bacteria Pseudomonas aeruginosa. The samples containing zinc oxide particles completely inhibited the growth of all three model strains. The virucidal activity of the CB was higher against human adenovirus serotype 5 (HAdV-5) than against human respiratory syncytial virus (HRSV-S2) after 60 min of exposure. The CBZ displayed higher virucidal activity with a Δlog of 0.9 against both viruses. Full article

Human multipotent mesenchymal stromal cells (hMSCs) are of significant therapeutic interest due to their ability to deliver oncolytic adenoviruses to tumors. This approach is also investigated for targeting head and neck squamous cell carcinomas (HNSCCs). HAdV-5-HexPos3, a recently reported capsid-modified vector based on human adenovirus type 5 (HAdV-5), showed strongly improved infection of both hMSCs and the HNSCC cell line UM-SCC-11B. Given that, we generated life cycle-unmodified and -modified replication-competent HAdV-5-HexPos3 vector variants and analyzed their replication within bone marrow- and adipose tissue-derived hMSCs. Efficient replication was detected for both life cycle-unmodified and -modified vectors. Moreover, we analyzed the migration of vector-carrying hMSCs toward different HNSCCs. Although migration of hMSCs to HNSCC cell lines was confirmed in vitro, no homing of hMSCs to HNSCC xenografts was observed in vivo in mice and in ovo in a chorioallantoic membrane model. Taken together, our data suggest that HAdV-5-HexPos3 is a potent candidate for hMSC-based oncolytic therapy of HNSCCs. However, it also emphasizes the importance of generating optimized in vivo models for the evaluation of hMSC as carrier cells. Full article

In this study, we investigated the features of the infectious process by simulating co-infection with SARS-CoV-2 and human adenovirus type 5 (HAdV-5) or influenza A virus (IAV) in vitro and in vivo. The determination of infectious activity of viruses and digital PCR demonstrated that during simultaneous and sequential HAdV-5 followed by SARS-CoV-2 infection in vitro and in vivo, the HAdV-5 infection does not interfere with replication of SARS-CoV-2. The hamsters co-infected and mono-infected with SARS-CoV-2 exhibited nearly identical viral titers and viral loads of SARS-CoV-2 in the lungs. The hamsters and ferrets co-infected by SARS-CoV-2- and IAV demonstrated more pronounced clinical manifestations than mono-infected animals. Additionally, the lung histological data illustrate that HAdV-5 or IAV and SARS-CoV-2 co-infection induces more severe pathological changes in the lungs than mono-infection. The expression of several genes specific to interferon and cytokine signaling pathways in the lungs of co-infected hamsters was more upregulated compared to single infected with SARS-CoV-2 animals. Thus, co-infection with HAdV-5 or IAV and SARS-CoV-2 leads to more severe pulmonary disease in animals. Full article

Adenovirus ocular infections are common ocular viral infections seen worldwide, for which there is no approved antiviral therapy available. Ranpirnase is a novel ribonuclease which preferentially degrades tRNA resulting in an inhibition of protein synthesis. The study goal was to determine the anti-adenoviral activity of topical formulations of ranpirnase (OKG-0301) on adenoviral replication in the Ad5/NZW rabbit ocular replication model. NZW rabbits were inoculated in both eyes with human adenovirus type 5 (HAdV5) after corneal scarification. A day later, topical therapy was initiated in both eyes with 0.03% OKG-0301, 0.003% OKG-0301, saline or 0.5% cidofovir. Eyes were cultured to determine HAdV5 eye titers over 2 weeks. OKG-0301 (0.03% and 0.003%) and 0.5% cidofovir decreased viral titers compared to saline. Furthermore, both OKG-0301 formulations and 0.5% cidofovir shortened the duration of the HAdV5 infection compared to saline. Both 0.03% OKG-0301 and 0.003% OKG-0301 demonstrated increased antiviral activity compared to saline in the Ad5/NZW rabbit ocular replication model. The antiviral activity of the OKG-0301 groups was similar to that of the positive antiviral control, 0.5% cidofovir. Ranpirnase (OKG-0301) may be a potential candidate for a topical antiviral for adenoviral eye infections. Further clinical development is warranted. Full article

Human adenoviruses (HAdV) are a prevalent cause of diarrhea in children all over the world. Adenoviral infections are responsible for 2% to 10% of diarrheic cases. A long-term investigation was required to gain better knowledge about the incidence of HAdV in Egypt. Herein, we conducted 5 years of detection, isolation, and genotyping of HAdV in fecal and sewage samples from 2016 to 2020, in Cairo, Egypt using molecular and cell culture assays. Human adenoviruses were identified in 35 of 447 fecal samples (7.8%), but only 53.3% (64/120) of the sewage samples. Children under the age of two had the highest positive rate for HAdV infection (77.1%). Species F of HAdV was the most common prevalent genotype in fecal and sewage samples, at 88.5% and 85.9%, respectively. The most prevalent genotypes detected in fecal samples were HAdV-41 (71.2%), HAdV-40 (17.2%), HAdV-6 (5.7%), and HAdV-1 (5.7%). In contrast, the most common genotypes in sewage samples were HAdV-41 (64%), HAdVs-40 (21.8%), HAdV-6 (7.8%), HAdV-1 (4.7%), and HAdV-2 (1.6%). HAdV was detected in all months of the year, with a peak period for clinical samples from December to February (p < 0.001), which matched Egypt’s rainy season, while the monthly distribution of HAdV in sewage samples remained consistent throughout the year, with no statistically significant peak period. Interestingly, the HAdV-type 41 genotype was the most common genotype during all of the years of this study. Throughout a 5-year period, our work revealed the infection rate, seasonal distribution, virus isolates, and genetic diversity of HAdV infections in environmental and clinical samples in Cairo, Egypt. Non-enteric adenovirus types (1, 2 and 6), as well as enteric adenovirus (41 and 40), may play a key role in gastroenteritis in Egypt. Full article

Human Adenovirus (HAdV) infection occurs in 14–16% of patients in the early months after pediatric hematopoietic cell transplantation (HCT) and this correlates with a higher risk of developing HAdV disease and overall 6-month mortality. The main risk factors for HAdV infection are T-cell depletion of the graft by ex vivo CD34+ selection or in vivo use of alemtuzumab or anti-thymocyte serum, the development of grade III-IV graft versus host disease (GVHD), the type of donor (unrelated donor, cord blood, haploidentical, or HLA mismatched parent), and severe lymphopenia (<0.2 × 10⁹/L). The prevention of HAdV disease is based on early intervention with antivirals in the asymptomatic patient when the permitted viral load threshold in the blood (≥10^2–3 copies/mL) and/or in the stool (10⁹ copies/g stool) is exceeded. Cidofovir, a monophosphate nucleotide analog of cytosine, is the primary drug for preemptive therapy, used at 5 mg/kg/week for 2 weeks followed by 3–5 mg/kg every 2 weeks. The alternative schedule is 1 mg/kg every other day (three times/week). Enhancing virus-specific T-cell immunity in the first months post-HCT by donor-derived or third-party-derived virus-specific T cells represents an innovative and promising way of intervention, applicable both in prevention and therapeutic settings. Full article

The core of Cyclolinopeptide A (CLA, cyclo(LIILVPPFF)), responsible for its high immunosuppressive activity, contains a Pro-Pro-Phe-Phe sequence. A newly synthesized cyclic tetrapeptide, cyclo(Pro-Pro-β³-HoPhe-Phe) (denoted as 4B8M) bearing the active sequence of CLA, was recently shown to exhibit a wide array of anti-inflammatory properties in mouse models. In this investigation, we demonstrate that the peptide significantly inhibits the replication of human adenovirus C serotype 5 (HAdV-5) and Herpes simplex virus type-1 (HSV-1) in epithelial lung cell line A-549, applying Cidofovir and Acyclovir as reference drugs. Based on a previously established mechanism of its action, we propose that the peptide may inhibit virus replication by the induction of PGE2 acting via EP2/EP4 receptors in epithelial cells. In summary, we reveal a new, antiviral property of this anti-inflammatory peptide. Full article

Viral and bacterial diseases are among the greatest concerns of humankind since ancient times. Despite tremendous pharmacological progress, there is still a need to search for new drugs that could treat or support the healing processes. A rich source of bioactive compounds with antiviral potency include plants such as black chokeberry and elderberry. The aim of this study was to assess the in vitro antiviral ability of an originally designed double-standardized blend of extracts from Aronia melanocarpa (Michx.) Elliot and Sambucus nigra L. (EAM-ESN) or separated extracts of A. melanocarpa (EAM) or S. nigra (ESN) against four human respiratory tract viruses: influenza A virus (A/H1N1), betacoronavirus-1 (HCoV-OC43) belonging to the same β-coronaviruses as the current pandemic SARS-CoV-2, human herpesvirus type 1 (HHV-1), and human adenovirus type 5 (HAdV-5). Antiviral assays (AVAs) were used to evaluate the antiviral activity of the plant extracts in a cell-present environment with extracts tested before, simultaneously, or after viral infection. The virus replication was assessed using the CPE scale or luminescent assay. The EAM-ESN blend strongly inhibited A/H1N1 replication as well as HCoV-OC43, while having a limited effect against HHV-1 and HAdV-5. This activity likely depends mostly on the presence of the extract of S. nigra. However, the EAM-ESN blend possesses more effective inhibitory activity toward virus replication than its constituent extracts. A post-infection mechanism of action of the EAM-ESN make this blend the most relevant for potential drugs and supportive treatments; thus, the EAM-ESN blend might be considered as a natural remedy in mild, seasonal respiratory viral infections. Full article

Human adenoviruses (HAdV) cause a variety of infections in human hosts, from self-limited upper respiratory tract infections in otherwise healthy people to fulminant pneumonia and death in immunocompromised patients. Many HAdV enter polarized epithelial cells by using the primary receptor, the Coxsackievirus and adenovirus receptor (CAR). Recently published data demonstrate that a potent neutrophil (PMN) chemoattractant, interleukin-8 (IL-8), stimulates airway epithelial cells to increase expression of the apical isoform of CAR (CAR^Ex8), which results in increased epithelial HAdV type 5 (HAdV5) infection. However, the mechanism for PMN-enhanced epithelial HAdV5 transduction remains unclear. In this manuscript, the molecular mechanisms behind PMN mediated enhancement of epithelial HAdV5 transduction are characterized using an MDCK cell line that stably expresses human CAR^Ex8 under a doxycycline inducible promoter (MDCK-CAR^Ex8 cells). Contrary to our hypothesis, PMN exposure does not enhance HAdV5 entry by increasing CAR^Ex8 expression nor through activation of non-specific epithelial endocytic pathways. Instead, PMN serine proteases are responsible for PMN-mediated enhancement of HAdV5 transduction in MDCK-CAR^Ex8 cells. This is evidenced by reduced transduction upon inhibition of PMN serine proteases and increased transduction upon exposure to exogenous human neutrophil elastase (HNE). Furthermore, HNE exposure activates epithelial autophagic flux, which, even when triggered through other mechanisms, results in a similar enhancement of epithelial HAdV5 transduction. Inhibition of F-actin with cytochalasin D partially attenuates PMN mediated enhancement of HAdV transduction. Taken together, these findings suggest that HAdV5 can leverage innate immune responses to establish infections. Full article

The human adenovirus type 5 (HAdV5) infects epithelial cells of the upper and lower respiratory tract. The virus causes lysis of infected cells and thus enables spread of progeny virions to neighboring cells for the next round of infection. The mechanism of adenovirus virion egress across the nuclear barrier is not known. The human adenovirus death protein (ADP) facilitates the release of virions from infected cells and has been hypothesized to cause membrane damage. Here, we set out to answer whether ADP does indeed increase nuclear membrane damage. We analyzed the nuclear envelope morphology using a combination of fluorescence and state-of-the-art electron microscopy techniques, including serial block-face scanning electron microscopy and electron cryo-tomography of focused ion beam-milled cells. We report multiple destabilization phenotypes of the nuclear envelope in HAdV5 infection. These include reduction of lamin A/C at the nuclear envelope, large-scale membrane invaginations, alterations in double membrane separation distance and small-scale membrane protrusions. Additionally, we measured increased nuclear membrane permeability and detected nuclear envelope lesions under cryoconditions. Unexpectedly, and in contrast to previous hypotheses, ADP did not have an effect on lamin A/C reduction or nuclear permeability. Full article

Most approved vaccines against COVID-19 have to be administered in a prime/boost regimen. We engineered a novel vaccine based on a chimeric human adenovirus 5 (hAdV5) vector. The vaccine (named CoroVaxG.3) is based on three pillars: (i) high expression of Spike to enhance its immunodominance by using a potent promoter and an mRNA stabilizer; (ii) enhanced infection of muscle and dendritic cells by replacing the fiber knob domain of hAdV5 by hAdV3; (iii) use of Spike stabilized in a prefusion conformation. The transduction with CoroVaxG.3-expressing Spike (D614G) dramatically enhanced the Spike expression in human muscle cells, monocytes and dendritic cells compared to CoroVaxG.5 that expressed the native fiber knob domain. A single dose of CoroVaxG.3 induced a potent humoral immunity with a balanced Th1/Th2 ratio and potent T-cell immunity, both lasting for at least 5 months. Sera from CoroVaxG.3-vaccinated mice was able to neutralize pseudoviruses expressing B.1 (wild type D614G), B.1.117 (alpha), P.1 (gamma) and B.1.617.2 (delta) Spikes, as well as an authentic P.1 SARS-CoV-2 isolate. Neutralizing antibodies did not wane even after 5 months, making this kind of vaccine a likely candidate to enter clinical trials. Full article

A common viral replication strategy is characterized by the assembly of intracellular compartments that concentrate factors needed for viral replication and simultaneously conceal the viral genome from host-defense mechanisms. Recently, various membrane-less virus-induced compartments and cellular organelles have been shown to represent biomolecular condensates (BMCs) that assemble through liquid-liquid phase separation (LLPS). In the present work, we analyze biophysical properties of intranuclear replication compartments (RCs) induced during human adenovirus (HAdV) infection. The viral ssDNA-binding protein (DBP) is a major component of RCs that contains intrinsically disordered and low complexity proline-rich regions, features shared with proteins that drive phase transitions. Using fluorescence recovery after photobleaching (FRAP) and time-lapse studies in living HAdV-infected cells, we show that DBP-positive RCs display properties of liquid BMCs, which can fuse and divide, and eventually form an intranuclear mesh with less fluid-like features. Moreover, the transient expression of DBP recapitulates the assembly and liquid-like properties of RCs in HAdV-infected cells. These results are of relevance as they indicate that DBP may be a scaffold protein for the assembly of HAdV-RCs and should contribute to future studies on the role of BMCs in virus-host cell interactions. Full article