Search Results (103)

Background/Objectives: Lung squamous cell carcinoma (SCC), a major subtype of non-small cell lung cancer, remains a significant clinical challenge due to a scarcity of actionable molecular targets and the limited effectiveness of current targeted therapies. Emerging treatment strategies inhibit the gene expression of lineage survival oncogenes such as ΔNp63 and SOX2. CRISPR interference (CRISPRi) is a promising method to downregulate these genes; however, the efficacy depends on effective delivery. Here, we focused on the delivery system using nanobubbles (NBs) and ultrasound (US) for site-specific CRISPRi delivery to SCC. We evaluated the therapeutic efficacy of plasmid-based CRISPRi (pCRISPRi) targeting SOX2 or ΔNp63 using intratumoral pCRISPRi/NBs injections followed by US. Methods: A mixture of NBs and pCRISPRi was injected directly into the tumors and exposed to US-induced cavitation to facilitate pCRISPRi uptake. Tumor volume was measured every other day, and apoptosis was assessed by TUNEL assay. Results: In a lung SCC xenograft model, NBs/US-mediated pCRISPRi delivery induced apoptosis and significantly suppressed tumor growth. Conclusions: These findings suggest that US-guided, NB-facilitated delivery of pCRISPRi can locally suppress lineage survival oncogenes and trigger tumor cell death, representing a promising targeted therapy for lung SCC. Additionally, this platform could be adapted to other cancers by targeting alternative factors. Full article

Avian pathogenic Escherichia coli (APEC) poses a global threat to poultry health and public safety due to its high lethality, limited treatment options, and potential for zoonotic transmission via the food chain. However, long-term genomic surveillance remains limited, especially in countries like China where poultry farming is highly intensive. This study aimed to characterize the population structure, virulence traits, and antimicrobial resistance of 81 APEC isolates from diseased chickens collected over 16 years from Shandong and neighboring provinces in eastern China. The isolates were grouped into seven Clermont phylogroups, with A and B1 being dominant. MLST revealed 27 STs, and serotyping identified 29 O and 16 H antigens, showing high genetic diversity. The minor phylogroups (B2, C, D, E, G) encoded more virulence genes and had higher virulence-plasmid ColV carriage, with enrichment for iron-uptake, protectins, and extraintestinal toxins. In contrast, the dominant phylogroups A and B1 primarily carried adhesin and enterotoxin genes. Antimicrobial resistance was widespread: 76.5% of isolates were multidrug-resistant. The minor phylogroups exhibited higher tetracycline resistance (mediated by tet(A)), whereas the major phylogroups showed increased resistance to third- and fourth-generation cephalosporins (due to bla_CTX-M-type ESBL genes). These findings offer crucial data for APEC prevention and control, safeguarding the poultry industry and public health. Full article

Recombinant adeno-associated virus (rAAV) is the leading vector for gene replacement therapy; however, the roles and regulation of host proteins in rAAV production remain incompletely understood. In this comparative proteomic analysis, we focused on proteins in the nucleus, the epicenter of DNA uptake, transcription, capsid assembly, and packaging. HEK-293 cells were analyzed under the following three conditions: (i) untransfected, (ii) mock-transfected with the ITR and an unrelated plasmid, and (iii) triple-transfected with rAAV2 production plasmids. Cells were harvested at 24 and 72 h post-transfection, and nuclear fractions were processed using filter-aided sample preparation (FASP) followed by nano-scale liquid chromatography–tandem mass spectrometry (nLC-Orbitrap MS/MS). Across all samples, we identified 3384 proteins, revealing significant regulatory changes associated with transfection and rAAV production. Transfection alone accounted for some of the most substantial proteomic shifts, while rAAV production induced diverse regulatory changes linked to cell cycle control, structure, and metabolism. STRING analysis of significantly regulated proteins also identified an enrichment of those associated with the Gene Ontology (GO) term ‘response to virus’. Additionally, we examined proteins with reported relation to adenoviral components. Our findings help to unravel the complexity of rAAV production, identify interesting targets for further investigation, and may contribute to improving rAAV yield. Full article

The amino acid membrane transporters of grape species take part in metabolic pathways that play crucial roles in nitrogen trafficking and in the synthesis of secondary metabolites. Therefore, identifying these amino acid transporters and defining their functional properties might have further applications in crop improvement and, hence, relevance to human nutrition. The VvCAT2 (Cation Amino acid Transporter) transporter cDNA has been isolated and cloned into a specific plasmid for over-expression in Escherichia coli. The expressed protein, after purification by Ni²⁺-chelating chromatography, has been functionally characterized in an experimental model of proteoliposomes by measuring the uptake of radiolabeled compounds. Arginine was revealed to be the best substrate, confirming the role of CAT2 in nitrogen trafficking in plant cells and within sub-cellular spaces, given its plausible localization in vacuoles. The transporter activity is modulated by pH, osmotic imbalance and ATP. The transport kinetics have been measured. Overall, the obtained data indicate the capacity of VvCAT2 in transporting arginine, making it a possible target for crop improvement with a relevance to human health. Full article

Glioblastoma is the most prevalent and aggressive form of brain malignancy. Actual treatments face several challenges due to its high aggressiveness and poor prognosis. The chemotherapeutic agent temozolomide (TMZ) has limited therapeutic efficacy, and mutations in the tumour protein p53 gene (TP53) have been associated with treatment resistance. Thus, this study aimed to explore an innovative therapeutic strategy to enhance treatment efficacy of GBM. Previously, our team had developed a WRAP5 cell-penetrating peptide (CPP) functionalized with a transferrin receptor ligand (Tf) for the targeted delivery of TMZ and a p53-encoding plasmid to glioma cells. Our research had elucidated the circadian oscillations of the clock genes in the U87 glioma cells by employing two different computational models and observed that T16 and T8 time points revealed the highest circadian activity for Bmal1 and Per2 genes, respectively. Similar analysis was conducted for the transferrin receptor, which revealed that T7 and T8 were the key time points for its expression. A confocal microscopy study indicated the highest intracellular uptake of complexes and p53 mRNA expression at T8, the time point with the highest Per2 and transferrin receptor expression. Following mRNA analysis, the evaluation of p53 levels confirmed transcriptional changes at the protein level, and that T16 appears to be a favourable time point for enhancing therapeutic efficacy in U87 glioblastoma cells. These findings suggested that synchronizing the complexes’ administration with the biological clock of GBM cells may significantly improve glioblastoma therapeutics. Full article

Background: The marine bacterium Vibrio campbellii has been a model system for the study of bacterial quorum sensing and is increasingly recognized as a formidable aquatic animal pathogen. While genetically tractable, the study of this species in basic and applied research still relies upon laborious and time-consuming conjugation methods for plasmid DNA transformation. Methods: In this study, we developed an electroporation protocol using the most studied strain of this species, V. campbellii ATCC BAA-1116. An electroporation efficiency of up to 3 × 10⁴ CFU/μg DNA was demonstrated using derived parameters (10 kV/cm, 400 Ω, 25 μF), which took cell growth phase at harvest, plasmid DNA amount, and recovery conditions into account. The electroporation protocol was tested using several different plasmids and with additional strains of V. campbellii and sister species V. harveyi. Results: Interestingly, of the eight other V. campbellii strains tested, only three others, which also happened to be the three most recent environmental isolates with the fewest number of laboratory passages, were amenable to electroporation-mediated transformation. Conclusions: This electroporation protocol expands the tool set for studying V. campbellii and provides interesting insights into DNA transformation and uptake in this and related bacterial species. Full article

Background/Objectives: Gene therapy has emerged as a promising strategy for treating a wide range of diseases. However, a major challenge remains in developing efficient and safe delivery systems for genetic material. Nanoparticles, particularly chitosan nanoparticles (CNPs), have gained significant attention as a potential solution. This study focuses on designing a SARS-CoV-2 plasmid DNA (pDNA) conjugated with CNPs and evaluating its in vitro delivery efficiency. Methods: The Omicron Spike DNA sequence was inserted into the pIRES2-eGFP expression vector, and CNPs were synthesized with optimized physicochemical properties to enhance stability, cellular uptake, and transfection efficiency. The conjugate was characterized using UV-Vis, FT-IR, DLS, and TEM techniques. Transfection efficiency was assessed and compared to the commercially available TurboFect reagent as a control. Results: CNPs-pDNA polyplexes with an average size of 159.0 ± 33.1 nm (TEM), a zeta potential of +19.7 ± 0.3 mV, and 100% ± 0.0 encapsulation efficiency were developed as a non-viral delivery system. CNPs efficiently serve as a delivery vehicle for the constructed pDNA without altering cell morphology, achieving transfection efficiencies of 62–74%, compared to 55–70% for TurboFect. Furthermore, RT-qPCR confirmed the expression of Spike mRNA, and Western blot assays validated the expression of Spike protein. Notably, Spike protein expression from CNPs was found to be two-fold higher than the control at 96 h post-transfection. Conclusions: These findings suggest that CNPs are a promising and versatile platform for delivering genetic material. Importantly, this study highlights the intrinsic properties of chitosan, without the use of additional ligands, as a key factor in achieving efficient gene delivery. Full article

Background/Objectives: The incidence of Ceftazidime/Avibactam (CZA)-resistant Klebsiella pneumoniae isolate co-producing Klebsiella pneumoniae carbapenemase 2 (KPC-2) and Vietnamese extended-spectrum β-lactamase 25 (VEB-25) has been on the rise in Greece over the past five years. This study investigates the isolation of ST323 K. pneumoniae isolates co-resistant to CZA and cefiderocol (FDC) from colonized and infected patients in a single hospital in Athens. Methods: CZA-resistant K. pneumoniae strains were isolated from 5 ICU patients from 27 December 2023 to 22 January 2024. Antimicrobial susceptibility was tested against a panel of agents. Whole-genome sequencing of the isolates was carried out to identify the acquired resistance genes and mutations that were associated with CZA and FDC resistance. Results: The K. pneumoniae isolates belonged to ST323 and harbored bla_KPC-2 and bla_VEB-25. The isolates had a minimum inhibitory concentration (MIC) of >256 mg/L for CZA and 32 mg/L for FDC, due to the disrupted catecholate siderophore receptor Fiu. bla_VEB-25 was located on an IncC non-conjugative plasmid and on a ~14 kb multidrug resistance (MDR) region comprising 15 further acquired resistance genes. Transformation studies showed that the bla_VEB-25-carrying plasmid provided resistance to most of the β-lactams tested, including CZA. The isolates remained susceptible to carbapenems, imipenem/relebactam, and meropenem/vaborbactam. The plasmid harbored the citrate-dependent iron (III) uptake system (fecIRABCDE), which increased the MIC of FDC from ≤0.08 mg/L to 2 mg/L. Conclusions: The bla_VEB-25 gene was associated with IncC plasmids which are important contributors to the spread of key antibiotic resistance genes. Strict infection control measures must be elaborated upon to prevent the spread of extensively drug-resistant organisms such as those described here. Full article

Background/Objectives: Virus-like particles (VLPs) represent an attractive platform for delivering vaccine formulations, combining a high biosafety profile with a potent immune-stimulatory ability. VLPs are non-infectious, non-replicating, self-assembling nanostructures that can be exploited to efficiently expose membrane-tethered glycoproteins such as the SARS-CoV-2 Spike (S) protein, the main target of approved preventive vaccines. Here, we describe the development and preclinical validation of Simian Immunodeficiency Virus (SIV)-based GFP-labeled VLPs displaying S from the B.1.617.2 (Delta) variant (VLP/S-Delta) for inducing persistent anti-SARS-CoV-2 neutralizing antibodies (nAbs) and S-specific T cell responses in mice. Methods: SIV-derived VLP/S-Delta were produced by co-transfecting a plasmid expressing SIVGag-GFP, required for VLP assembly and quantification by flow virometry, a plasmid encoding the Delta S protein deleted in the cytoplasmic tail (CT), to improve membrane binding, and a VSV.G-expressing plasmid, to enhance VLP uptake. Recovered VLPs were titrated by flow virometry and characterized in vitro by transmission electron microscopy (TEM) and confocal microscopy (CLSM). BALB/c mice were immunized intramuscularly with VLP/S-Delta following a prime–boost regimen, and humoral and cellular immune responses were assessed. Results: VLP/S-Delta were efficiently pseudotyped with CT-truncated S-Delta. After BALB/c priming, VLP/S-Delta elicited both specific anti-RBD IgGs and anti-Delta nAbs that significantly increased after the boost and were maintained over time. The prime–boost vaccination induced similar levels of cross-nAbs against the ancestral Wuhan-Hu-1 strain as well as cross-nAbs against Omicron BA.1, BA.2 and BA.4/5 VoCs, albeit at lower levels. Moreover, immunization with VLP/S-Delta induced S-specific IFNγ-producing T cells. Conclusions: These data suggest that SIV-based VLPs are an appropriate delivery system for the elicitation of efficient and sustained humoral and cellular immunity in mice, paving the way for further improvements in the immunogen design to enhance the quality and breadth of immune responses against different viral glycoproteins. Full article

Background: Inefficient cellular uptake is a significant limitation to the efficacy of DNA vaccines. In this study, we introduce S-Cr9T, a stearyl-modified cell-penetrating peptide (CPP) designed to enhance DNA vaccine delivery by forming stable complexes with plasmid DNA, thereby protecting it from degradation and promoting efficient intracellular uptake. Methods and Results: In vitro studies showed that S-Cr9T significantly improved plasmid stability and transfection efficiency, with optimal performance at an N/P ratio of 0.25. High-content imaging revealed that the S-Cr9T–plasmid complex stably adhered to the cell membrane, leading to enhanced plasmid uptake and transfection. In vivo, S-Cr9T significantly increased antigen expression and triggered a robust immune response, including a threefold increase in IFN-γ secretion and several hundred-fold increases in antibody levels compared to control groups. Conclusions: These findings underscore the potential of S-Cr9T to enhance DNA vaccine efficacy, offering a promising platform for advanced gene therapy and vaccination strategies. Full article

Cell-penetrating peptides (CPPs) are a diverse group of peptides, typically composed of 4 to 40 amino acids, known for their unique ability to transport a wide range of substances—such as small molecules, plasmid DNA, small interfering RNA, proteins, viruses, and nanoparticles—across cellular membranes while preserving the integrity of the cargo. CPPs exhibit passive and non-selective behavior, often requiring functionalization or chemical modification to enhance their specificity and efficacy. The precise mechanisms governing the cellular uptake of CPPs remain ambiguous; however, electrostatic interactions between positively charged amino acids and negatively charged glycosaminoglycans on the membrane, particularly heparan sulfate proteoglycans, are considered the initial crucial step for CPP uptake. Clinical trials have highlighted the potential of CPPs in diagnosing and treating various diseases, including cancer, central nervous system disorders, eye disorders, and diabetes. This review provides a comprehensive overview of CPP classifications, potential applications, transduction mechanisms, and the most relevant algorithms to improve the accuracy and reliability of predictions in CPP development. Full article

Transfection of mammalian and human cell lines in medical research both are key technologies in molecular biology and genetic engineering. A vast variety of techniques to facilitate transfection exists including different chemical and nanoparticle-based agents as mediators of nucleic acid uptake, with nanoparticles composed of the lipids DOSPA/DOPE belonging to the established type of agents. We show that inverse-nanoemulsion-derived protein nanohydrogels (NanoTrans-gels), prepared by a simple synthesis protocol, are suited to transfect two model cancer cell lines (MCF7 and A549) with high efficiency. The transfection efficiency was analyzed in comparison to the DOSPA/DOPE-dependent protocols as a reference method. Since nanogel-based transfection outperformed the Lipofectamine-dependent technique in our experiments, we believe that the NanoTrans-gels loaded with plasmid DNA may open new avenues for simple and efficient transfection for humans and probably also other mammalian cell lines and may develop into a general tool for standard transfection procedures in cell biology laboratories. Full article

Objective: Multidrug-resistant, highly pathogenic Escherichia coli strains are the primary causative agents of intestinal and extraintestinal human diseases. The extensive utilization of antibiotics for farm animals has been identified as a contributing factor to the emergence and dissemination of E. coli strains that exhibit multidrug resistance and possess high pathogenic potential. Consequently, a significant research objective is to examine the genetic diversity of pathogenic E. coli strains and to identify those that may pose a threat to human health. Methods: In this study, we present the results of genome sequencing and analysis, as well as the physiological characterization of E. coli strain APEC 36, which was isolated from the liver of a broiler chicken with generalized colibacillosis. Results: We found that APEC 36 possess a number of mechanisms of antibiotic resistance, including antibiotic efflux, antibiotic inactivation, and antibiotic target alteration/replacement/protection. The most widely represented group among these mechanisms was that of antibiotic efflux. This finding is consistent with the strain’s documented resistance to multiple antibiotics. APEC 36 has an extremely rare variant of the beta-lactamase CTX-M-169. Notwithstanding the multitude of systems for interfering with foreign DNA present in the strain, seven plasmids have been identified, three of which may possess novel replication origins. Additionally, qnrS1, which confers resistance to fluoroquinolones, was found to be encoded in the genome rather than in the plasmid. This suggests that the determinants of antibiotic resistance may be captured in the genome and stably transmitted from generation to generation. Conclusions: The APEC 36 strain has genes for toxins, adhesins, protectins, and an iron uptake system. The obtained set of genetic and physiological characteristics allowed us to assume that this strain has a high pathogenic potential for humans. Full article

Hepatitis B virus (HBV) infection remains a major health threat with limited treatment options. One of various new antiviral strategies is based on a fusion of Staphylococcus aureus nuclease (SN) with the capsid-forming HBV core protein (HBc), termed coreSN. Through co-assembly with wild-type HBc-subunits, the fusion protein is incorporated into HBV nucleocapsids, targeting the nuclease to the encapsidated viral genome. However, coreSN expression was based on transfection of a plasmid vector. Here, we explored whether introducing protein transduction domains (PTDs) into a fluorescent coreSN model could confer cell-penetrating properties for direct protein delivery into cells. Four PTDs were inserted into two different positions of the HBc sequence, comprising the amphiphilic translocation motif (TLM) derived from the HBV surface protein PreS2 domain and three basic PTDs derived from the Tat protein of human immunodeficiency virus-1 (HIV-1), namely Tat4, NP, and NS. To directly monitor the interaction with cells, the SN in coreSN was replaced with the green fluorescent protein (GFP). The fusion proteins were expressed in E. coli, and binding to and potential uptake by human cells was examined through flow cytometry and fluorescence microscopy. The data indicate PTD-dependent interactions with the cells, with evidence of uptake in particular for the basic PTDs. Uptake was enhanced by a triplicated Simian virus 40 (SV40) large T antigen nuclear localization signal (NLS). Interestingly, the basic C terminal domain of the HBV core protein was found to function as a novel PTD. Hence, further developing cell-permeable viral capsid protein fusions appears worthwhile. Full article

The present study shows the genomic characterization of three pathogenic Escherichia coli hybrid strains. All strains were previously characterized as diarrheagenic pathotypes (DEC), obtained from feces. The three sequenced strains have genes that encode adhesins (fimH and iha) and iron uptake systems (iucC and iutA). Antibiotic resistance genes were also found for fluoroquinolone and aminoglycoside families in the three strains. The presence of genomic islands (GIs) in the sequenced study strains presented 100% identity (Ec-25.2) and 99% identity (Ec-36.1) with previously reported Extraintestinal Pathogenic E. coli (ExPEC) strains. The Ec-36.4 strain shared a 99% identity with GI from the Enterotoxigenic E. coli (ETEC) pathotype of the diarrheagenic E. coli strain. Ec-25.2 belongs to ST69 and harbors a FimH27 variant, while Ec-36.1 and Ec-36.4 belong to ST4238 and share a FimH54 variant. Four incompatibility groups associated with conjugative plasmids were identified (IncFIB, IncF11, IncI1, and IncB/O/K/Z), as well as Insertion Sequences and MITEs elements. Full article