Bacteriophages: Status quo and emerging trends toward one health approach

The alarming rise in antimicrobial resistance (AMR) among the drug-resistant pathogens has been attributed to the ESKAPEE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, Enterobacter sp., and Escherichia coli). Recently, these AMR microbes have become difficult to treat, as they have rendered the existing therapeutics ineffective. Thus, there is an urgent need for effective alternatives to lessen or eliminate the current infections and limit the spread of emerging diseases under the "One Health" framework. Bacteriophages (phages) are naturally occurring biological resources with extraordinary potential for biomedical, agriculture/food safety, environmental protection, and energy production. Specific unique properties of phages, such as their bactericidal activity, host specificity, potency, and biocompatibility, make them desirable candidates in therapeutics. The recent biotechnological advancement has broadened the repertoire of phage applications in nanoscience, material science, physical chemistry, and soft-matter research. Herein, we present a comprehensive review, coupling the substantial aspects of phages with their applicability status and emerging opportunities in several interdependent areas under one health concept. Consolidating the recent state-of-the-art studies that integrate human, animal, plant, and environment health, the following points have been highlighted: (i) The biomedical and pharmacological advantages of phages and their antimicrobial derivatives with particular emphasis on in-vivo and clinical studies. (ii) The remarkable potential of phages to be altered, improved, and applied for drug delivery, biosensors, biomedical imaging, tissue engineering, energy, and catalysis. (iii) Resurgence of phages in biocontrol of plant, food, and animal-borne pathogens. (iv) Commercialization of phage-based products, current challenges, and perspectives.

Innate Immunity Mechanisms in Marine Multicellular Organisms

The innate immune system provides an adequate response to stress factors and pathogens through pattern recognition receptors (PRRs), located on the surface of cell membranes and in the cytoplasm. Generally, the structures of PRRs are formed by several domains that are evolutionarily conserved, with a fairly high degree of homology in representatives of different species. The orthologs of TLRs, NLRs, RLRs and CLRs are widely represented, not only in marine chordates, but also in invertebrates. Study of the interactions of the most ancient marine multicellular organisms with microorganisms gives us an idea of the evolution of molecular mechanisms of protection against pathogens and reveals new functions of already known proteins in ensuring the body’s homeostasis. The review discusses innate immunity mechanisms of protection of marine invertebrate organisms against infections, using the examples of ancient multicellular hydroids, tunicates, echinoderms, and marine worms in the context of searching for analogies with vertebrate innate immunity. Due to the fact that mucous membranes first arose in marine invertebrates that have existed for several hundred million years, study of their innate immune system is both of fundamental importance in terms of understanding molecular mechanisms of host defense, and of practical application, including the search of new antimicrobial agents for subsequent use in medicine, veterinary and biotechnology.

Regulation of Immune Homeostasis via Muramyl Peptides-Low Molecular Weight Bioregulators of Bacterial Origin

Metabolites and fragments of bacterial cells play an important role in the formation of immune homeostasis. Formed in the course of evolution, symbiotic relationships between microorganisms and a macroorganism are manifested, in particular, in the regulation of numerous physiological functions of the human body by the innate immunity receptors. Low molecular weight bioregulators of bacterial origin have recently attracted more and more attention as drugs in the prevention and composition of complex therapy for a wide range of diseases of bacterial and viral etiology. Signaling networks show cascades of causal relationships of deterministic phenomena that support the homeostasis of multicellular organisms at different levels. To create networks, data from numerous biomedical and clinical research databases were used to prepare expert systems for use in pharmacological and biomedical research with an emphasis on muramyl dipeptides. Muramyl peptides are the fragments of the cell wall of Gram-positive and Gram-negative bacteria. Binding of muramyl peptides with intracellular NOD2 receptors is crucial for an immune response on pathogens. Depending on the microenvironment and duration of action, muramyl peptides possess positive or negative regulation of inflammation. Other factors, such as genetic, pollutions, method of application and stress also contribute and should be taken into account. A system biology approach should be used in order to systemize all experimental data for rigorous analysis, with the aim of understanding intrinsic pathways of homeostasis, in order to define precise medicine therapy and drug design.

Filamentous bacteriophages, natural nanoparticles, for viral vaccine strategies

Filamentous bacteriophages are natural nanoparticles formed by the self-assembly of structural proteins that have the capability of replication and infection. They are used as a highly efficient vaccine platform to enhance immunogenicity and effectively stimulate the innate and adaptive immune response. Compared with traditional vaccines, phage-based vaccines offer thermodynamic stability, biocompatibility, homogeneity, high carrying capacity, self-assembly, scalability, and low toxicity. This review summarizes recent research on phage-based vaccines in virus prevention. In addition, the expression systems of filamentous phage-based virus vaccines and their application principles are discussed. Moreover, the prospect of the prevention of emerging infectious diseases, such as coronavirus 2019 (COVID-19), is also discussed.

Dual Effect of Low-Molecular-Weight Bioregulators of Bacterial Origin in Experimental Model of Asthma

Asthma is one of the most common noncommunicable diseases, affecting over 200 million people. A large number of drugs control asthma attacks, but there is no effective therapy. Identification of reasons for asthma and preventing this disease is a relevant task. The influence of bacterial components is necessary for the normal development of the immune system and the formation of an adequate immune response to antigens. In the absence of microorganisms or their insufficient exposure, the prerequisites are formed for excessive reactivity to harmless antigens. In the present study, we analyzed cellular and humoral factors in a standard mouse model of OVA-induced asthma modified by 5-fold intraperitoneal injection of bacterial cell wall fragments of glucosaminylmuramyl dipeptide (GMDP) 5 μg/animal or 1 μg lipopolysaccharide (LPS) per animal for 5 days before sensitization by ovalbumin (OVA). Preliminary administration of LPS or GMDP to animals significantly reduced goblet cells as well as the number of neutrophils, lymphocytes, and eosinophils in bronchoalveolar lavage, wherein GMDP corrected neutrophilia to a 2-fold degree, and LPS reduced the severity of eosinophilia by 1.9 times. With OVA administration of GMDP or LPS at the sensitization stage, an increase in the total number of bronchoalveolar lavage cells due to neutrophils, macrophages, lymphocytes, and eosinophils in relation to the group with asthma without GMDP or LPS was observed. The administration of GMDP or LPS to normal mice without asthma for 5 days had no statistically significant effect on the change in the number and population composition of cells in bronchoalveolar lavage in comparison with the control group receiving PBS. As a result of a study in a mouse model of asthma, a dual effect of LPS and GMDP was established: the introduction of LPS or GMDP before sensitization reduces neutrophilia and eosinophilia, while the introduction of LPS or GMDP together with an allergen significantly increases neutrophilia and eosinophilia. The study of the immunoglobulin status shows that in normal-asthma mice, GMDP and LPS slightly increase IgA in bronchoalveolar lavage; at the same time, in the asthma model, injections of GMDP or LPS before sensitization contribute to a significant decrease in IgA (2.6 times and 2.1 times, respectively) in BALF and IgE (2.2 times and 2.0 times, respectively) in blood serum. In an experimental model of asthma, the effect of GMDP and LPS was multidirectional: when they are repeatedly administered before sensitization, the bacterial components significantly reduce the severity of the allergic process, while in the case of a joint injection with an allergen, they increase the influx of macrophages, lymphocytes, and neutrophils into the lungs, which can aggravate the course of pathological process. Thus, the insufficient effect of antigens of a bacterial nature, in particular, with prolonged use of antibiotics can be compensated for by substances based on low-molecular-weight bioregulators of bacterial origin to establish the missing signals for innate immunity receptors, whose constant activation at a certain level is necessary to maintain homeostasis.

Identification and expression analysis of antigenic sites of hepatitis C virus genotype 3a NS3 and NS5A genes of local isolate

Background

Hepatitis C virus, a silent killer, has infected 71 million people globally. The recombinant viral antigenic proteins might be used in the early diagnosis of HCV infection. The NS3 and NS5A genes of HCV function in HCV replication and influence host cellular factors that are involved in HCV pathogenesis. The current study was designed to select NS3 and NS5A antigenic sites, amplified, cloned, and expressed in order to find out better assays for diagnosis or drug and vaccine development. The antigenic sites within NS3 and NS5A genes were selected and confirmed through sequencing and were cloned. The antigenic recombinant proteins were expressed in bacterial strain E. coli BL21ply*, and the expression was confirmed by western blotting by using gene-specific and vector-specific antibodies.

Results

Specific antigenic regions within the NS3 and NS5A genes of the HCV 3A genotype were amplified. PCR results showed 328 bp and 747 bp antigenic regions, respectively. The regions were confirmed by DNA sequencing and cloned into a bacterial expression vector. Expression analysis showed 12 kDa and 28 kDa of NS3 and NS5A antigenic recombinant proteins, respectively. Taken together, these studies will help to analyze the genetic variability within the local HCV isolates as these antigenic recombinant proteins were quite important in the screening of HCV-infected patients.

Conclusions

This study might help to enhance the progress in the treatment of HCV infection through the modeling of HCV non-structural genes (NS3 and NS5A) from local isolate, and it might also present the viral genes as potential therapeutic targets.

Mesenchymal Stem Cells Can Both Enhance and Inhibit the Cellular Response to DNA Immunization by Genes of Nonstructural Proteins of the Hepatitis C Virus

Despite extensive research, there is still no vaccine against the hepatitis C virus (HCV). The aim of this study was to investigate whether MSCs can exhibit adjuvant properties during DNA vaccination against hepatitis C. We used the pcNS3-NS5B plasmid encoding five nonstructural HCV proteins and MSCs derived from mice bone marrow. Five groups of DBA mice were immunized with the plasmid and/or MSCs in a different order. Group 1 was injected with the plasmid twice at intervals of 3 weeks; Group 2 with the plasmid, and after 24 h with MSCs; Group 3 with MSCs followed by the plasmid the next day; Group 4 with only MSCs; and Group 5 with saline. When the MSCs were injected prior to DNA immunization, the cell immune response to HCV proteins assessed by the level of IFN-γ synthesis was markedly increased compared to DNA alone. In contrast, MSCs injected after DNA suppressed the immune response. Apparently, the high level of proinflammatory cytokines detected after DNA injection promotes the conversion of MSCs introduced later into the immunosuppressive MSC2. The low level of cytokines in mice before MSC administration promotes the high immunostimulatory activity of MSC1 in response to a DNA vaccine. Thus, when administered before DNA, MSCs are capable of exhibiting promising adjuvant properties.

Mesenchymal Stem Cells Can Both Enhance and Inhibit the Cellular Response to DNA Immunization by Genes of Nonstructural Proteins of the Hepatitis C Virus

Despite extensive research, there is still no vaccine against the hepatitis C virus (HCV). The aim of this study was to investigate whether MSCs can exhibit adjuvant properties during DNA vaccination against hepatitis C. We used the pcNS3-NS5B plasmid encoding five nonstructural HCV proteins and MSCs derived from mice bone marrow. Five groups of DBA mice were immunized with the plasmid and/or MSCs in a different order. Group 1 was injected with the plasmid twice at intervals of 3 weeks; Group 2 with the plasmid, and after 24 h with MSCs; Group 3 with MSCs followed by the plasmid the next day; Group 4 with only MSCs; and Group 5 with saline. When the MSCs were injected prior to DNA immunization, the cell immune response to HCV proteins assessed by the level of IFN-γ synthesis was markedly increased compared to DNA alone. In contrast, MSCs injected after DNA suppressed the immune response. Apparently, the high level of proinflammatory cytokines detected after DNA injection promotes the conversion of MSCs introduced later into the immunosuppressive MSC2. The low level of cytokines in mice before MSC administration promotes the high immunostimulatory activity of MSC1 in response to a DNA vaccine. Thus, when administered before DNA, MSCs are capable of exhibiting promising adjuvant properties.

Mesenchymal Stem Cells Can Both Enhance and Inhibit the Cellular Response to DNA Immunization by Genes of Nonstructural Proteins of the Hepatitis C Virus

Despite extensive research, there is still no vaccine against the hepatitis C virus (HCV). The aim of this study was to investigate whether MSCs can exhibit adjuvant properties during DNA vaccination against hepatitis C. We used the pcNS3-NS5B plasmid encoding five nonstructural HCV proteins and MSCs derived from mice bone marrow. Five groups of DBA mice were immunized with the plasmid and/or MSCs in a different order. Group 1 was injected with the plasmid twice at intervals of 3 weeks; Group 2 with the plasmid, and after 24 h with MSCs; Group 3 with MSCs followed by the plasmid the next day; Group 4 with only MSCs; and Group 5 with saline. When the MSCs were injected prior to DNA immunization, the cell immune response to HCV proteins assessed by the level of IFN-γ synthesis was markedly increased compared to DNA alone. In contrast, MSCs injected after DNA suppressed the immune response. Apparently, the high level of proinflammatory cytokines detected after DNA injection promotes the conversion of MSCs introduced later into the immunosuppressive MSC2. The low level of cytokines in mice before MSC administration promotes the high immunostimulatory activity of MSC1 in response to a DNA vaccine. Thus, when administered before DNA, MSCs are capable of exhibiting promising adjuvant properties.

Human Herpesviruses Increase the Severity of Hepatitis

Simple Summary

More than 300 million people worldwide suffer from hepatitis B or hepatitis C and more than 1 million people die each year from cirrhosis and liver cancer. In some cases, the nature of hepatitis remains unclear. The purpose of this research was to assess the prevalence of human herpesviruses (cytomegalovirus, Epstein–Barr virus, and herpesvirus type 6) in patients with hepatitis, and to examine their effect on the disease severity. In the clinical materials of 377 patients with acute or chronic hepatitis, DNA of these three herpesviruses was detected in the blood in 13.5% of patients with viral hepatitis B or C and in 10.1% of patients with hepatitis of unspecified etiology. The cirrhosis was diagnosed in patients with herpesviruses 3 times more often than in patients without them. In patients with hepatitis C, the incidence of herpesviruses was higher in the tissue samples of liver biopsies (38.7%) than in the blood. Clinical and virological indicators of hepatitis were considerably higher in the patients with coinfection. Since in patients with hepatitis the presence of herpesviruses is associated with a more severe course of the disease, the detection, and herpesvirus DNA monitoring will help to adjust the course of therapy.

Abstract

Acute and chronic liver diseases are a major global public health problem; nevertheless, the etiology of 12–30% of cases remains obscure. The purpose of this research was to study the incidence of human herpesviruses (HHVs) cytomegalovirus, Epstein–Barr virus (EBV), and HHV-6 in patients with hepatitis and to examine the effect of HHV on the disease severity. We studied the clinical materials of 259 patients with hepatitis treated in Infectious Clinic n.1 (Moscow) and the archived materials of 118 patients with hepatitis C. HHV DNA was detected in the whole blood in 13.5% of patients with hepatitis B or C and in 10.1% of patients with hepatitis of unspecified etiology. EBV demonstrated the highest incidence (58.1%). Cirrhosis was diagnosed in 50% of patients with HHV and in 15.6% of patients without HHV. In patients with hepatitis C, the frequency of HHV was higher in liver biopsy (38.7%) compared to blood. The clinical and virological indicators of hepatitis were considerably higher in patients with coinfection. Conclusion: HHV detected in patients with viral hepatitis has been associated with a significant effect on the severity of the disease, and we suggest monitoring HHV DNA in patients with severe hepatitis and/or poor response to antiviral drugs.

Strategies for Using Muramyl Peptides - Modulators of Innate Immunity of Bacterial Origin - in Medicine

The spread of infectious diseases is rampant. The emergence of new infections, the irrational use of antibiotics in medicine and their widespread use in agriculture contribute to the emergence of microorganisms that are resistant to antimicrobial drugs. By 2050, mortality from antibiotic-resistant strains of bacteria is projected to increase up to 10 million people per year, which will exceed mortality from cancer. Mutations in bacteria and viruses are occurring faster than new drugs and vaccines are being introduced to the market. In search of effective protection against infections, new strategies and approaches are being developed, one of which is the use of innate immunity activators in combination with etiotropic chemotherapy drugs. Muramyl peptides, which are part of peptidoglycan of cell walls of all known bacteria, regularly formed in the body during the breakdown of microflora and considered to be natural regulators of immunity. Their interaction with intracellular receptors launches a sequence of processes that ultimately leads to the increased expression of genes of MHC molecules, pro-inflammatory mediators, cytokines and their soluble and membrane-associated receptors. As a result, all subpopulations of immunocompetent cells are activated: macrophages and dendritic cells, neutrophils, T-, B- lymphocytes and natural killer cells for an adequate response to foreign or transformed antigens, manifested both in the regulation of the inflammatory response and in providing immunological tolerance. Muramyl peptides take part in the process of hematopoiesis, stimulating production of colony-stimulating factors, which is the basis for their use in the treatment of oncological diseases. In this review we highlight clinical trials of drugs based on muramyl peptides, as well as clinical efficacy of drugs mifamurtide, lycopid, liasten and polimuramil. Such a multifactorial effect of muramyl peptides and a well-known mechanism of activity make them promising drugs in the treatment and preventing of infectious, allergic and oncological diseases, and in the composition of vaccines.

Genetically Modified Mouse Mesenchymal Stem Cells Expressing Non-Structural Proteins of Hepatitis C Virus Induce Effective Immune Response

Hepatitis C virus (HCV) is one of the major causes of chronic liver disease and leads to cirrhosis and hepatocarcinoma. Despite extensive research, there is still no vaccine against HCV. In order to induce an immune response in DBA/2J mice against HCV, we obtained modified mouse mesenchymal stem cells (mMSCs) simultaneously expressing five nonstructural HCV proteins (NS3-NS5B). The innate immune response to mMSCs was higher than to DNA immunization, with plasmid encoding the same proteins, and to naïve unmodified MSCs. mMSCs triggered strong phagocytic activity, enhanced lymphocyte proliferation, and production of type I and II interferons. The adaptive immune response to mMSCs was also more pronounced than in the case of DNA immunization, as exemplified by a fourfold stronger stimulation of lymphocyte proliferation in response to HCV, a 2.6-fold higher rate of biosynthesis, and a 30-fold higher rate of secretion of IFN-γ, as well as by a 40-fold stronger production of IgG2a antibodies to viral proteins. The immunostimulatory effect of mMSCs was associated with pronounced IL-6 secretion and reduction in the population of myeloid derived suppressor cells (MDSCs). Thus, this is the first example that suggests the feasibility of using mMSCs for the development of an effective anti-HCV vaccine.

Advances in the T7 phage display system (Review)

The present review describes the advantages and updated applications of the T7 phage display system in bioscience and medical science. Current phage display systems are based on various bacteriophage vectors, including M13, T7, T4 and f1. Of these, the M13 phage display is the most frequently used, however, the present review highlights the advantages of the T7 system. As a phage display platform, M13 contains single‑stranded DNA, while the T7 phage consists of double‑stranded DNA, which exhibits increased stability and is less prone to mutation during replication. Additional characteristics of the T7 phage include the following: The T7 phage does not depend on a protein secretion pathway in the lytic cycle; expressed peptides and proteins are usually located on the C‑terminal region of capsid protein gp10B, which avoids problems associated with steric hindrance; and T7 phage particles exhibit high stability under various extreme conditions, including high temperature and low pH, which facilitates effective high‑throughput affinity elutriation. Recent applications of the T7 phage display system have been instrumental in uncovering mechanisms of molecular interaction, particularly in the fields of antigen discovery, vaccine development, protein interaction, and cancer diagnosis and treatment.

Modulation of Cell Death Pathways by Hepatitis C Virus Proteins in Huh7.5 Hepatoma Cells

The hepatitis C virus (HCV) causes chronic liver disease leading to fibrosis, cirrhosis, and hepatocellular carcinoma. HCV infection triggers various types of cell death which contribute to hepatitis C pathogenesis. However, much is still unknown about the impact of viral proteins on them. Here we present the results of simultaneous immunocytochemical analysis of markers of apoptosis, autophagy, and necrosis in Huh7.5 cells expressing individual HCV proteins or their combinations, or harboring the virus replicon. Stable replication of the full-length HCV genome or transient expression of its core, Е1/Е2, NS3 and NS5B led to the death of 20-47% cells, 72 h posttransfection, whereas the expression of the NS4A/B, NS5A or NS3-NS5B polyprotein did not affect cell viability. HCV proteins caused different impacts on the activation of caspases-3, -8 and -9 and on DNA fragmentation. The structural core and E1/E2 proteins promoted apoptosis, whereas non-structural NS4A/B, NS5A, NS5B suppressed apoptosis by blocking various members of the caspase cascade. The majority of HCV proteins also enhanced autophagy, while NS5A also induced necrosis. As a result, the death of Huh7.5 cells expressing the HCV core was induced via apoptosis, the cells expressing NS3 and NS5B via autophagy-associated death, and the cells expressing E1/E2 glycoproteins or harboring HCV the replicon via both apoptosis and autophagy.

Hepatitis C virus proteins activate NRF2/ARE pathway by distinct ROS-dependent and independent mechanisms in HUH7 cells

Hepatitis C virus (HCV) is a highly pathogenic human virus associated with liver fibrosis, steatosis, and cancer. In infected cells HCV induces oxidative stress. Here, we show that HCV proteins core, E1, E2, NS4B, and NS5A activate antioxidant defense Nrf2/ARE pathway via several independent mechanisms. This was demonstrated by the analysis of transient co-expression in Huh7 cells of HCV proteins and luciferase reporters. Expression, controlled by the promoters of stress-response genes or their minimal Nrf2-responsive elements, was studied using luminescence assay, RT-qPCR and/or Western-blot analysis. All five proteins induced Nrf2 activation by protein kinase C in response to accumulation of reactive oxygen species (ROS). In addition, expression of core, E1, E2, NS4B, and NS5A proteins resulted in the activation of Nrf2 in a ROS-independent manner. The effect of core and NS5A was mediated through casein kinase 2 and phosphoinositide-3 kinase, whereas those of NS4B, E1, and E2, were not mediated by either PKC, CK2, PI3K, p38, or ERK. Altogether, on the earliest stage of expression HCV proteins induced a strong up-regulation of the antioxidant defense system. These events may underlie the harmful effects of HCV-induced oxidative stress during acute stage of hepatitis C.

The successful immune response against hepatitis C nonstructural protein 5A (NS5A) requires heterologous DNA/protein immunization

The aim of this study was to evaluate the immunogenicity of NS5A protein of human hepatitis C virus (HCV) when delivered as naked DNA (NS5A DNA), or recombinant protein (rNS5A). DBA/2J mice received NS5A DNA, rNS5A, or NS5A DNA/rNS5A in different prime-boost combinations with a peptidoglycan Immunomax((R)). The weakest response was induced after rNS5A prime and NS5A DNA boost; rNS5A alone induced an immune response with a strong Th2-component; and NS5A DNA alone, a relatively weak secretion of IL-2 and IFN-gamma. The most efficient was co-injection of NS5A DNA and rNS5A, which induced a significant increase in CD4(+) and CD8(+) T-cell counts, anti-NS5A antibodies, specific T-cell proliferation, and proinflammatory cytokine production in vitro against a broad spectrum of NS5A epitopes. Administration of the mixture of adjuvanted DNA and protein immunogens can be selected as the best regimen for further preclinical HCV-vaccine trials.