Search Results (121)

Background/Objectives: Radiotherapy (RT) is a mainstay of clinical cancer therapy that causes broad immune responses. The complement system is a pivotal effector mechanism in the innate immune response, but the impact of RT is less well understood. This study investigates the interaction between RT and the complement system as a possible approach to improve immune responses in cancer treatment. Methods: Human solid cancer (lung, prostate, liver, breast cancer), lymphoma, and leukemia cells were irradiated using X-rays and treated with polyclonal antibodies or anti-CD20 monoclonal antibodies, respectively. Chromium release assay was applied to measure cell lysis after radiation with or without complement-activating antibody treatment. The expression of membrane-bound complement regulatory proteins (mCRPs; CD46, CD55, CD59), which confer resistance against complement activation, CD20 expression, apoptosis, and radiation-induced DNA double-strand breaks (γH2AX), was measured by flow cytometry. The radiosensitivity of tumor cells was assessed by colony-forming assay. Results: We demonstrate that RT profoundly impacts complement function by upregulating the expression of membrane-bound complement regulatory proteins (mCRPs) on tumor cells in a dose- and time-dependent manner. Impaired complement-mediated tumor cell lysis could thus potentially contribute to radiotherapeutic resistance. We also observed RT-induced upregulation of CD20 expression on lymphoma and leukemic cells. Notably, complement activation prior to RT proved more effective in inducing RT-dependent early apoptosis compared to post-irradiation treatment. While complement modulation does not significantly alter RT-induced DNA-damage repair mechanisms or intrinsic radiosensitivity in cancer cells, our results suggest that combining RT with complement-based anti-cancer therapy may enhance complement-dependent cytotoxicity (CDC) and apoptosis in tumor cells. Conclusions: This study sheds light on the complex interplay between RT and the complement system, offering insights into potential novel combinatorial therapeutic strategies and a potential sequential structure for certain tumor types. Full article

Background: Iminosugars are natural or synthetic sugar analogues with a very broad spectrum of activities, including those against the most prominent bacterial pathogens, like P. aeruginosa or S. aureus. In a series of studies, we have demonstrated that one of the synthetic iminosugars, PDIA (beta-1-C-propyl-1,4-dideoxy-1,4-imino-L-arabinitol), possesses the ability to suppress biofilm production by different pathogenic bacteria without inhibiting their growth. Thereby, PDIA is able to influence experimental skin infection caused by S. aureus. Methods: To elucidate molecular mechanisms by which PDIA impedes biofilm formation by S. aureus, a transcriptomic study was performed in which a biofilm-producing S. aureus strain was grown in the presence of PDIA for 24 and 48 h in comparison to a control without the iminosugar. The RNA was then isolated, converted into cDNA, sequenced, and data analysis was performed. Results: It appeared that PDIA caused the down-regulation of many bacteriophage genes responsible for the processes of bacterial cell lysis, and some genes responsible for cell wall degradation were also down-regulated. Among the 25 most upregulated genes were those representing the phosphotransferase system (PTS), which is required for carbohydrate uptake and control of carbon metabolism. The ranking of the most significant down-regulated genes after 24 h exposure to PDIA shows that they predominantly coded for both the synthesis and lysis of the peptidoglycan. Conclusions: We have shown here that the influence of PDIA on the expression of S. aureus genes is broad and affects many genes encoding metabolism and ribosomes. Full article

Bacteriophages are a unique and fascinating group of viruses, known for their highly specific ability to infect and replicate within bacterial cells. While their potential as antibacterial agents has been recognized for decades, recent research has revealed complex interactions between phages and the human immune system, offering new insights into their role in immune modulation. New evidence reveals a dynamic and intricate relationship between phages and cytokines, suggesting their ability to regulate inflammation, immune tolerance, and host–pathogen interaction. Herein, we review how phages affect the production of cytokines and the behavior of immune cells indirectly by lysis of bacterium or directly on mammalian cells. Phages have been shown to induce both pro- and anti-inflammatory responses and recently, they have been explored in personalized immunotherapy, cancer immunotherapy, and microbiome modulation, which are the focus of this review. Several challenges remain despite significant progress, including practical obstructions related to endotoxins along with host microbiome variability and regulatory issues. Nevertheless, the potential of bacteriophages to modulate immune responses makes them attractive candidates for the future of precision medicine. Full article

Severe dental pulp inflammation can lead to tissue lysis and destruction, underscoring the necessity for effective treatment of pulpitis. N-acetyltransferase 10 (NAT10)-mediated N4-acetylcytidine (ac⁴C) modification has recently emerged as a key regulator in inflammatory processes. However, whether NAT10 affects the inflammatory response in human dental pulp stem cells (hDPSCs) remains unelucidated. In this study, elevated NAT10 expression was observed in pulpitis tissues and LPS-stimulated hDPSCs. Knockdown of NAT10 led to reduced inflammatory gene expression and lower reactive oxygen species (ROS) production in LPS-stimulated hDPSCs, while the chemotactic migration of macrophages was also suppressed. Similar results were observed when hDPSCs were treated with Remodelin, an inhibitor of NAT10. Differentially expressed genes identified through RNA sequencing were significantly enriched in inflammatory signaling pathways after NAT10 depletion. Among the differential genes, pentraxins 3 (PTX3) was identified as the potential target gene due to the presence of the ac⁴C modification site and its known ability to regulate dental pulp inflammation. The mRNA and protein levels of PTX3 were reduced in NAT10-deficient cells, along with a decrease in its mRNA stability. Exogenous PTX3 supplementation partially reversed the inflammatory inhibition induced by NAT10 knockdown. Further evidence in vivo revealed that Remodelin treatment attenuated the severity of dental pulp inflammation in rats with pulpitis. In summary, these data indicated that NAT10 deficiency inhibited the stability of PTX3 mRNA and further inhibited hDPSC inflammation, while Remodelin might be a potential therapeutic agent for pulp capping. Full article

Soil viruses, ubiquitous and abundant biological entities that are integral to microbial communities, exert pivotal impacts on ecosystem functionality, particularly within carbon (C) and nitrogen (N) cycles, through intricate interactions with bacteria, archaea, fungi, and other microbial taxa. While their contributions to soil ecosystem dynamics are increasingly elucidated, the specific roles of soil viruses in karst forest soil remain largely underexplored. Karst ecosystems (covering 15% of the global terrestrial surface) are characterized by unique geological formations, thin and patchy soil layers, high pH and Ca²⁺, and rapid hydrological dynamics, collectively fostering unique environmental conditions that may shape viral ecology and modulate C and N cycling. This perspective synthesizes existing knowledge of soil viral functions with the distinctive characteristics of karst forest soil, proposing potential mechanisms by which soil viruses could influence C and N cycling in such fragile ecosystems. Soil viruses regulate C and N cycles both directly and indirectly via their interactions with microbial hosts, mainly including shaping the microbial community structure, mediating horizontal gene transfer and microbial metabolism, increasing C and N availability and alleviating nutrient limitations, promoting C and N sequestration, and mitigating climate change. This work aims to bridge soil viral ecology and karst biogeochemical cycles, providing insights into sustainable forest stewardship and climate resilience. We delineate critical knowledge gaps and propose future perspectives, advocating for targeted metagenomic and long-term experimental studies into viral diversity, virus–host-environment interactions, and temporal dynamics. Specifically, we advocate the following research priorities to advance our understanding of soil viruses in karst forest ecosystems in future studies: (I) soil viral diversity, abundance, and activity: characterizing the diversity, abundance, and activity of soil viruses in karst forests using metagenomics and complementary molecular approaches; (II) virus–host interactions: investigating the dynamics between the viruses and key microbial taxa involved in C and N cycling; (III) biogeochemical impacts: quantifying the contributions of viral lysis and horizontal gene transfer to C and N fluxes within karst forest soil; and (IV) modeling the viral impacts on C and N cycles: developing integrative models that incorporate soil virus-mediated processes into existing karst forest soil biogeochemical frameworks at different temporal and spatial scales. Such efforts are essential to validate the hypothesized viral roles and underlying mechanisms, offering a foundation for nature-based solutions to facilitate C and N cycling and support ecological restoration in vulnerable karst regions amid global climate change. Full article

Streptococcus pneumoniae (pneumococcus) is a significant human pathogen responsible for a range of diseases from mild infections to invasive pneumococcal diseases, particularly affecting children, the elderly, and immunocompromised individuals. Despite pneumococcal conjugate vaccines having reduced disease incidence, challenges persist due to serotype diversity, vaccine coverage gaps, and antibiotic resistance. This review highlights the role of LytA, a key autolysin (N-acetylmuramoyl-l-alanine amidase), in pneumococcal biology. LytA regulates autolysis, contributes to inflammation, and biofilm formation, and impairs bacterial clearance. It also modulates complement activation, aiding immune evasion. LytA expression is influenced by environmental signals and genetic regulation and is tied to competence for genetic transformation, which is an important virulence trait, particularly in meningitis. With the increase in antibiotic resistance, LytA has emerged as a potential therapeutic target. Current research explores its use in bacteriolytic therapies, vaccine development, and synergistic antibiotic strategies. Various compounds, including synthetic peptides, plant extracts, and small molecules, have been investigated for their ability to trigger LytA-mediated bacterial lysis. Future directions include the development of novel anti-pneumococcal interventions leveraging LytA’s properties while overcoming vaccine efficacy and resistance-related challenges. Human challenge models and animal studies continue to deepen our understanding of pneumococcal pathogenesis and potential treatment strategies. Full article

Viral infection and lysis drive bacterial diversity and abundances, ultimately regulating global biogeochemical cycles. Infection can follow lytic or temperate routes, with lytic dynamics suppressing bacterial population growth and temperate infection enhancing it. Given that bacterial over-proliferation is a pervasive threat to ecosystems, determining which infection dynamic dominates a given ecosystem is a central question in viral ecology. However, the fields that describe and test the rules of viral infection—theoretical ecology and environmental microbiology, respectively—remain disconnected. To address this, we simulated common empirical approaches to analyze and distinguish between the predictions of three theoretical models mechanistically representing lytic to temperate infection dynamics. By doing so, we found that the models have remarkably similar predictions despite their mechanistic differences, as shown by PCA and correlation analyses. Essentially, the models are only discernable under simulated nutrient addition, where lytic models become less stable with no increase in host densities while the temperate model remains stable and has elevated host abundances. Highlighting this difference between the models, we present a dichotomous key illustrating how researchers can determine whether lytic or temperate infection dynamics dominate their ecosystem of interest using common metrics and empirical approaches. Full article

NK cells have traditionally been classified as effectors of innate immunity, even though they also exhibit some features of adaptive immunity such as memory. NK cells contribute to the lysis and growth inhibition of cancer, mediating direct cytotoxicity and antibody-dependent cellular cytotoxicity (ADCC) and regulating the functions of other immune cells, respectively. NK cells regulate the function of other immune cells via the release of inflammatory cytokines and chemokines. Currently, NK cell therapeutics in oral cancer have been less efficient due to several limitations, as follows: (a) lower percentages of NK cells in peripheral blood immune cells; (b) limited survival and decreased function of NK cells, especially in the tumor microenvironment; and (c) a lack of tools or methodologies to expand and activate NK cells to the levels that are required for the effective targeting of oral cancer. To overcome these limitations, we established and demonstrated a novel technology for activating and expanding highly functional NK cells coined as supercharged NK (sNK) cells. This review summarizes the characteristics of sNK cells and highlights their superior anti-cancer activity when compared to primary activated NK cells. Full article

Conditions like diabetes mellitus (DM), cancer, infections, inflammation, cardiovascular diseases (CVDs), and gastrointestinal (GI) disorders continue to have a major global impact on mortality and morbidity. Medicinal plants have been used since ancient times in ethnomedicine (e.g., Ayurveda, Unani, Traditional Chinese Medicine, and European Traditional Medicine) for the treatment of a wide range of disorders. Plants are a rich source of diverse phytoconstituents with antidiabetic, anticancer, antimicrobial, antihypertensive, antioxidant, antihyperlipidemic, cardioprotective, immunomodulatory, and/or anti-inflammatory activities. This review focuses on the 35 plants most commonly reported for the treatment of these major disorders, with a particular emphasis on their traditional uses, phytoconstituent contents, pharmacological properties, and modes of action. Active phytomolecules with therapeutic potential include cucurbitane triterpenoids, diosgenin, and limonoids (azadiradione and gedunin), which exhibit antidiabetic properties, with cucurbitane triterpenoids specifically activating Glucose Transporter Type 4 (GLUT4) translocation. Capsaicin and curcumin demonstrate anticancer activity by deactivating NF-κB and arresting the cell cycle in the G2 phase. Antimicrobial activities have been observed for piperine, reserpine, berberine, dictamnine, chelerythrine, and allitridin, with the latter two triggering bacterial cell lysis. Quercetin, catechin, and genistein exhibit anti-inflammatory properties, with genistein specifically suppressing CD8+ cytotoxic T cell function. Ginsenoside Rg1 and ginsenoside Rg3 demonstrate potential for treating cardiovascular diseases, with ginsenoside Rg1 activating PPARα promoter, and the PI3K/Akt pathway. In contrast, ternatin, tannins, and quercitrin exhibit potential in gastrointestinal disorders, with quercitrin regulating arachidonic acid metabolism by suppressing cyclooxygenase (COX) and lipoxygenase activity. Further studies are warranted to fully investigate the clinical therapeutic benefits of these plants and their phytoconstituents, as well as to elucidate their underlying molecular mechanisms of action. Full article

Graves’ disease (GD) is an autoimmune disorder, driven by the appearance of circulating autoantibodies (Ab) against the thyroid stimulating hormone (TSH) receptor, thus causing hyperthyroidism. While antithyroid drugs, the only available treatment for GD, carry a significant risk of relapse, advances in immunology could pave the way for more effective therapies. Natural killer (NK) cells, divided into cytotoxic CD56^dim and cytokine-secreting CD56^bright subsets, regulate immune responses through cytokine production and cell lysis and may play a role in the pathogenesis of GD. To investigate their involvement, we conducted flow cytometry on peripheral blood samples from 131 GD patients at various stages (disease onset, on antithyroid drugs, and in remission) and 97 age- and sex-matched healthy controls (HC). We analyzed NK cell subsets, activating (CD16, CD69, NKG2D, NKp30) and inhibitory receptors (CD161, NKG2A), degranulation (CD107a), and intracellular cytokines expression (interferon γ, tumor necrosis factor α). Statistical comparisons were made between GD patients and HC and across disease stages. GD patients had a higher frequency of total NK cells (p < 0.028) and CD56^bright NK cells (p < 0.01) but a lower frequency of CD56^dim NK cells (p = 0.005) compared to HC. NK cells in GD patients expressed activating receptors more frequently, except for NKG2D, but had decreased cytokine expression and degranulation ability. At GD onset, patients had higher frequencies of total NK cells, CD56^bright NK cells, and NK cells expressing activating receptors compared to patients receiving ATD treatment and those in remission. CD161⁺ NK cells were lower at GD onset and returned to levels of HC following treatment. Correlation analysis revealed that free thyroxine (FT4) levels were inversely correlated with CD107a⁺ NK cells (p < 0.05) and positively correlated with CD69⁺ NK cells (p < 0.01). These findings suggest that hyperthyroidism impairs NK cell degranulation, with the increased frequency of NK cells potentially compensating for their reduced function. This dysfunction may contribute to the unregulated immune response in GD, highlighting NK cells as a potential target for novel therapeutic strategies. Full article

Salmonella is one of the main foodborne pathogens. Irrational antibiotic management has led to an increase in the incidence of multidrug-resistant strains. Bacteriophages may be an alternative method of food biopreservation and contribute to reducing the number of food poisonings requiring pharmacotherapy. This study aimed to isolate a bacteriophage (phage) targeting indigenous multidrug-resistant (MDR) Salmonella strains, followed by their biological, morphological, and genomic characterization. In this study we isolated Salmonella phage KKP_3822, targeting MDR Salmonella Manchester strain KKP 1213. Salmonella phage KKP_3822 retained high activity in the temperature range from −20 °C to 40 °C and active acidity from pH 3 to 11. Temperatures of 70 °C and 80 °C and extreme pH values (2 and 12) significantly reduced the phage titer. Its activity decreased proportionally to the time of UV exposure. Genome analysis (linear dsDNA with a length of 114,843 bp) revealed the presence of 27 tRNA genes. Proteins encoded by the vB_Sen-IAFB3822 phage were divided into functional modules related to (i) phage structure/assembly, (ii) DNA replication/modification/regulation, (iii) phage lysis, and (iv) DNA packaging into the capsid. No genes associated with antibiotic resistance or integration into the host genome, markers of temperate bacteriophages, were annotated in the Salmonella phage KKP_3822 genome. Based on morphological features and whole-genome sequence analysis, the newly isolated Salmonella phage KKP_3822 shows the greatest similarity to representatives of tailed phages from the Caudoviricetes class, Demerecviridae family, and Epseptimavirus genus. Genome analysis confirmed the virulent nature of the Salmonella phage KKP_3822, making it a potential candidate for food biocontrol. Full article

The complement system is a pivotal component of innate immunity, extensively studied in vertebrates but also present in invertebrates. This study explores the existence of a terminal complement pathway in the tunicate Botryllus schlosseri, aiming to understand the evolutionary integration of innate and adaptive immunity. Through transcriptome analysis, we identified a novel transcript, BsITCCP, encoding a protein with both MACPF and LDLa domains—a structure resembling that of vertebrate C9 but with a simpler organization. Phylogenetic reconstruction positions BsITCCP between invertebrate perforins and vertebrate terminal complement proteins, suggesting an evolutionary link. Localization studies confirmed that bsitccp is transcribed in cytotoxic morula cells (MCs), which are also responsible for producing other complement components like BsC3, BsMBL, BsMASP, and BsBf. Functional assays demonstrated that bsitccp transcription is upregulated in response to nonself challenges and is dependent on BsC3 activity; inhibition of BsC3 led to a significant reduction in BsITCCP expression. Electron microscopy revealed that MCs form contact with perforated yeast cells, indicating a possible mechanism of cell lysis similar to the immunological synapse observed in vertebrates. These findings suggest that a C3-governed lytic complement pathway exists in B. schlosseri, challenging the assumption that a C5 ortholog is necessary for such a pathway. This work enhances our understanding of the evolution of the complement system and suggests that invertebrates possess a terminal complement complex capable of mediating cell lysis, regulated by C3. Future studies will focus on confirming the pore-forming ability of BsITCCP and its role in the immunological synapse. Full article

The current knowledge of Staphylococcus warneri phages is limited, with few genomes sequenced and characterized. In this study, a prophage, vB_G30_01, isolated from Staphylococcus warneri G30 was characterized and evaluated for its lysogenic host range. The phage was studied using transmission electron microscopy and a host range. The phage genome was sequenced and characterized in depth, including phylogenetic and taxonomic analyses. The linear dsDNA genome of vB_G30_01 contains 67 predicted open reading frames (ORFs), classifying it within Bronfenbrennervirinae. With a total of 10 ORFs involved in DNA replication-related and transcriptional regulator functions, vB_G30_01 may play a role in the genetics and transcription of a host. Additionally, vB_G30_01 possesses a complete set of genes related to host lysogeny and lysis, implying that vB_G30_01 may influence the survival and adaptation of its host. Furthermore, a comparative genomic analysis reveals that vB_G30_01 shares high genomic similarity with other Staphylococcus phages and is relatively closely related to those of Exiguobacterium and Bacillus, which, in combination with the cross-infection assay, suggests possible cross-species infection capabilities. This study enhances the understanding of Staphylococcus warneri prophages, providing insights into phage–host interactions and potential horizontal gene transfer. Full article

The key factor that enables pathogenic bacteria to establish successful infections lies largely in their ability to escape the host’s immune response and adhere to host surfaces. Vitronectin (Vn) is a multidomain glycoprotein ubiquitously present in blood and the extracellular matrix of several tissues, where it plays important roles as a regulator of membrane attack complex (MAC) formation and as a mediator of cell adhesion. Vn has emerged as an intriguing target for several microorganisms. Vn binding by bacterial receptors confers protection from lysis resulting from MAC deposition. Furthermore, through its Arg-Gly-Asp (RGD) motif, Vn can bind several host cell integrins. Therefore, Vn recruited to the bacterial cell functions as a molecular bridge between bacteria and host surfaces, where it triggers several host signaling events that could promote bacterial internalization. Each bacterium uses different receptors that recognize specific Vn domains. In this review, we update the current knowledge of Vn receptors of major bacterial pathogens, emphasizing the role they may play in the host upon Vn binding. Focusing on the structural properties of bacterial proteins, we provide details on the residues involved in their interaction with Vn. Furthermore, we discuss the possible involvement of Vn adsorption on biomaterials in promoting bacterial adhesion on abiotic surfaces and infection. Full article

The ammonia/ammonium (NH₃/NH₄⁺, AM) concentration in human erythrocytes (RBCs) is significantly higher than in plasma. Two main possible mechanisms for AM transport, including simple and facilitated diffusion, are described; however, the driving force for AM transport is not yet fully characterized. Since the erythroid ammonium channel RhAG forms a structural unit with anion exchanger 1 (eAE1) within the ankyrin core complex, we hypothesized the involvement of eAE1 in AM transport. To evaluate the functional interaction between eAE1 and RhAG, we used a unique feature of RBCs to swell and lyse in isotonic NH₄⁺ buffer. The kinetics of cell swelling and lysis were analyzed by flow cytometry and an original laser diffraction method, adapted for accurate volume sensing. The eAE1 role was revealed according to (i) the changes in cell swelling and lysis kinetics, and (ii) changes in intracellular pH, triggered by eAE1 inhibition or the modulation of eAE1 main ligand concentrations (Cl⁻ and HCO₃⁻). Additionally, the AM import kinetics was analyzed enzymatically and colorimetrically. In NH₄⁺ buffer, RBCs concentration-dependently swelled and lysed when [NH₄⁺] exceeded 100 mM. Cell swelling and hemolysis were tightly regulated by chloride concentration. The complete substitution of chloride with glutamate prevented NH₄⁺-induced cell swelling and hemolysis, and the restoration of [Cl⁻] dose-dependently amplified the rates of RBC swelling and lysis and the percentage of hemolyzed cells. Similarly, eAE1 inhibition impeded cell swelling and completely prevented hemolysis. Accordingly, eAE1 inhibition, or a lack of chloride anions in the buffer, significantly decreased NH₄⁺ import. Our data indicate that the eAE1-mediated chloride gradient is required for AM transport. Taken together, our data reveal a new player in AM transport in RBCs. Full article