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Porcine reproductive and respiratory syndrome virus (PRRSV), a significant pathogen affecting the swine industry globally, has been shown to manipulate host cell processes, including autophagy, to facilitate its replication and survival within the host. Autophagy, an intracellular degradation process crucial for maintaining cellular homeostasis, can be hijacked by viruses for their own benefit. During PRRSV infection, autophagy plays a complex role, both as a defense mechanism of the host and as a tool exploited by the virus. This review explores the current understanding of the molecular mechanisms underlying autophagy induction under PRRSV infection, its impact on virus replication, and the potential implications for viral pathogenesis and antiviral strategies. By synthesizing the latest research findings, this article aims to enhance our understanding of the intricate relationship between autophagy and PRRSV, paving the way for novel therapeutic approaches against this swine pathogen. [ABSTRACT FROM AUTHOR]

There are few tumor cell subpopulations with stem cell characteristics in tumor tissue, defined as cancer stem cells (CSCs) or cancer stem-like cells (CSLCs), which can reconstruct neoplasms with malignant biological behaviors such as invasiveness via self-renewal and unlimited generation. The microenvironment that CSCs depend on consists of various cellular components and corresponding medium components. Among these factors existing at a variety of levels and forms, cytokine networks and numerous signal pathways play an important role in signaling transduction. These factors promote or maintain cancer cell stemness, and participate in cancer recurrence, metastasis, and resistance. This review aims to summarize the recent molecular data concerning the multilayered relationship between CSCs and CSC-favorable microenvironments. We also discuss the therapeutic implications of targeting this synergistic interplay, hoping to give an insight into targeting cancer cell stemness for tumor therapy and prognosis.

Pseudorabies virus (PRV) belongs to the Alphaherpesvirinae subfamily and serves as an exceptional animal model for investigating the infection mechanism of Herpes simplex virus type 1. Notably, PRV has the capability to infect a wide range of mammals, including humans, highlighting its potential as an overlooked zoonotic pathogen. The attachment and entry steps of PRV into host cells are crucial to accomplish its life cycle, which involve numerous cellular factors. In this mini review, we offer a comprehensive summary of current researches pertaining to the role of cellular factors in PRV attachment and entry stages, with the overarching goal of advancing the development of novel antiviral agents against this pathogen. [ABSTRACT FROM AUTHOR]

Osteoarthritis is caused by a complex interplay of genetic, metabolic, immunological, inflammatory, biochemical, and biomechanical factors. In recent years, a fairly large number of studies have been devoted to the role of cellular factors of the immune system in the development of osteoarthritis. The aim of the study was to analyze scientifc publications devoted to the study of cellular factors in the pathogenesis of osteoarthritis and to assess their signifcance in the development of joint pathology. Material and methods. The search for publications by keywords was carried out in the PubMed, Google Scholar, eLibrary databases and specialized journals related to therapy, rheumatology, traumatology and immunology from 2000 to 2022. Results and discussion. Summarizing modern ideas about the role of cellular factors of the immune system in the pathogenesis of osteoarthritis, it is necessary to note the presence of synovial inflammation, a key role in the development of which is assigned to macrophages. At the same time, patients with osteoarthritis are characterized by the predominance of classically activated macrophages with a pronounced pro-inflammatory effect. In addition, T lymphocytes also play an important role in the pathogenesis of joint damage. Among them, a special role is given to T helper cells, cytotoxic T lymphocytes and memory T cells. An imbalance of cytokines and chemokines produced by subpopulations of T lymphocytes is the reason for triggering a number of mechanisms for the onset and progression of osteoarthritis. A signifcant role in the development and progression of osteoarthritis is also assigned to neutrophils, which contribute to the development of inflammation. Neutrophil-produced elastase enhances cartilage degradation, chondrocyte apoptosis, unbalanced subchondral bone remodeling, and osteophyte formation. Conclusions. Knowledge of the role of cellular immune factors in the pathogenesis of osteoarthritis and ways to implement their effects determines the prospects for the use of immunotropic agents. Also, it should be taken into account that the occurrence and progression of osteoarthritis is due to the simultaneous combination of the influence of a wide range of various components, including risk factors, traumatic joint injury, etc.

Background: Skin cancer is the most prevalent type of cancer and melanoma is the deadliest kind of skin cancer in the world. Due to enhanced induction of apoptosis and ROS levels, low-level lasers can be utilized to destroy skin cancer cells. Lasers are used to treat some skin lesions. Vitamin A is beneficial in the prevention and treatment of skin cancer. Vitamin A inhibits the pathway of cancer signals in the skin and suppresses tumor growth. In this study, the combined effect of low-level laser radiation (LLL) and vitamin A on cellular factors of skin melanoma cancer cells was investigated. Methods: An in-vitro interventional laboratory study was performed in the cell culture laboratory of Medical Laser Research Center, Yara Institute in 2020-2021 (July 2020 to July 2021). First, A375 skin cancer cells were cultured in DMEM with 10% FBS. After preparation and culture of A375 cell lines, different concentrations of vitamin A (1, 5, 50, 100 μM) and LLL energy doses (1, 2, 5, 10 J/cm2) as treatments were done. Combination research of these treatments was performed to eliminate skin melanoma cancer cells. The rate of viability was determined using the MTT test, and the rate of apoptosis was determined using flow cytometry. Results: The results indicated that a low-level laser with energy dosages of two and 5 J/cm2 and vitamin A treatment with a concentration of 50 μM in the A375 skin cancer cell line had the lowest viability and the highest induction of apoptosis. Furthermore, the results of the combination of Vitamin A and LLL treatments showed a synergistic effect with a greater reduction in the viability of skin melanoma cells and a greater amount of apoptosis. Conclusion: In general, vitamin A and Low-level laser diminish the viability of cancer cells. Combination therapy of Low-level laser in the effective dose with vitamin A in optimal concentration provides anti-cancer effects. Further reductions in cancer cell viability caused by vitamin A and low-level laser radiation could pave the way for a novel approach in cancer treatment.

Attachment to and fusion with cell membranes are two major steps in the replication cycle of many human viruses. We focus on these steps for three enveloped viruses, i.e., HIV-1, IAVs, and SARS-CoV-2. Viral spike proteins drive the membrane attachment and fusion of these viruses. Dynamic interactions between the spike proteins and membrane receptors trigger their specific attachment to the plasma membrane of host cells. A single virion on cell membranes can engage in binding with multiple receptors of the same or different types. Such dynamic and multivalent binding of these viruses result in an optimal attachment strength which in turn leads to their cellular entry and membrane fusion. The latter process is driven by conformational changes of the spike proteins which are also class I fusion proteins, providing the energetics of membrane tethering, bending, and fusion. These viruses exploit cellular and membrane factors in regulating the conformation changes and membrane processes. Herein, we describe the major structural and functional features of spike proteins of the enveloped viruses including highlights on their structural dynamics. The review delves into some of the case studies in the literature discussing the findings on multivalent binding, membrane hemifusion, and fusion of these viruses. The focus is on applications of biophysical tools with an emphasis on single-particle methods for evaluating mechanisms of these processes at the molecular and cellular levels. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV), a significant pathogen affecting the swine industry globally, has been shown to manipulate host cell processes, including autophagy, to facilitate its replication and survival within the host. Autophagy, an intracellular degradation process crucial for maintaining cellular homeostasis, can be hijacked by viruses for their own benefit. During PRRSV infection, autophagy plays a complex role, both as a defense mechanism of the host and as a tool exploited by the virus. This review explores the current understanding of the molecular mechanisms underlying autophagy induction under PRRSV infection, its impact on virus replication, and the potential implications for viral pathogenesis and antiviral strategies. By synthesizing the latest research findings, this article aims to enhance our understanding of the intricate relationship between autophagy and PRRSV, paving the way for novel therapeutic approaches against this swine pathogen., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chen, Yu and Li.)

Enterovirus A71 (EV-A71) can cause hand, foot and mouth disease with neurological and systemic complications, most frequently affecting children and infants. We describe a cis-acting replication element (cre) with a conserved stem-loop structure within the EV-A71 2C-coding region. By site-directed mutagenesis and reverse genetics using the EV-A71 full-length genome and the EV-A71 replicon containing the firefly luciferase reporter gene in place of the P1 region, the stem-loop structure and the AAACA in the loop of the cre were confirmed to be required for the EV-A71 replication phenotype. EV-A71 genomes containing a mutation at the first or third A residue of AAACA could not be recovered. Insertion of a wild-type cre from EV-A71 or poliovirus in the 5’UTR led to successful recovery of the replication of nonviable mutants. Furthermore, the cre mutants showed lower binding capacity with the host cellular factor IGF2BP2, knockdown of which resulted in a significant decrease in EV-A71 production. All the available evidence shows the location independence but functional importance of the interaction of the cre with the cellular host for efficient production of EV-A71, contributing to the growing body of knowledge regarding picornavirus cres.

Background: Skin cancer is the most prevalent type of cancer and melanoma is the deadliest kind of skin cancer in the world. Due to enhanced induction of apoptosis and ROS levels, low-level lasers can be utilized to destroy skin cancer cells. Lasers are used to treat some skin lesions. Vitamin A is beneficial in the prevention and treatment of skin cancer. Vitamin A inhibits the pathway of cancer signals in the skin and suppresses tumor growth. In this study, the combined effect of low-level laser radiation (LLL) and vitamin A on cellular factors of skin melanoma cancer cells was investigated. Methods: An in-vitro interventional laboratory study was performed in the cell culture laboratory of Medical Laser Research Center, Yara Institute in 2020-2021 (July 2020 to July 2021). First, A375 skin cancer cells were cultured in DMEM with 10% FBS. After preparation and culture of A375 cell lines, different concentrations of vitamin A (1, 5, 50, 100 μM) and LLL energy doses (1, 2, 5, 10 J/cm2) as treatments were done. Combination research of these treatments was performed to eliminate skin melanoma cancer cells. The rate of viability was determined using the MTT test, and the rate of apoptosis was determined using flow cytometry. Results: The results indicated that a low-level laser with energy dosages of two and 5 J/cm2 and vitamin A treatment with a concentration of 50 μM in the A375 skin cancer cell line had the lowest viability and the highest induction of apoptosis. Furthermore, the results of the combination of Vitamin A and LLL treatments showed a synergistic effect with a greater reduction in the viability of skin melanoma cells and a greater amount of apoptosis. Conclusion: In general, vitamin A and Low-level laser diminish the viability of cancer cells. Combination therapy of Low-level laser in the effective dose with vitamin A in optimal concentration provides anti-cancer effects. Further reductions in cancer cell viability caused by vitamin A and low-level laser radiation could pave the way for a novel approach in cancer treatment. [ABSTRACT FROM AUTHOR]

Pleural mesothelioma is a deadly asbestos induced cancer. Less than 10% of mesothelioma patients survive 5 years post diagnosis. However survival can range from a few months to a number of years. Accurate prediction of survival is important for patients to plan for their remaining life, and for clinicians to determine appropriate therapy. One unusual features of mesothelioma is that patients frequently present with tumor-associated pleural effusions early in the course of the disease. To study whether cells and molecules present in pleural effusions provide prognostic information for mesothelioma. We profiled the cellular constituents and concentrations of 40 cytokines, chemokines and cellular factors (collectively “soluble factors”) involved in inflammatory and immune signalling pathways in pleural effusion samples from 50 mesothelioma patients.Associations with survival were evaluated by Cox proportional hazards regression methods. Results for the two soluble factors most significantly and independently associated with survival were validated in an independent set of samples (n= 51) using a separate assay system. Survival analysis revealed thatIL8, IL2Ra (CD25) and PF4 were independent determinants of a more negative prognosis in mesothelioma patients, independent of other known prognostic factors. Lipocalin2 and IL4 were associated with better prognosis. This study demonstrates that pleural effusions rich in a range of soluble factors are associated with poor prognosis. These findings will enhance our ability to prognosticate outcomes in mesothelioma patients. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the recently emerged virus responsible for the COVID-19 pandemic. Clinical presentation can range from asymptomatic disease and mild respiratory tract infection to severe disease with lung injury, multiorgan failure, and death. SARS-CoV-2 is the third animal coronavirus to emerge in humans in the 21st century, and coronaviruses appear to possess a unique ability to cross borders between species and infect a wide range of organisms. This is somewhat surprising as, except for the requirement of host cell receptors, cell–pathogen interactions are usually species-specific. Insights into these host–virus interactions will provide a deeper understanding of the process of SARS-CoV-2 infection and provide a means for the design and development of antiviral agents. In this study, we describe a complex analysis of SARS-CoV-2 infection using a genome-wide CRISPR-Cas9 knock-out system in HeLa cells overexpressing entry receptor angiotensin-converting enzyme 2 (ACE2). This platform allows for the identification of factors required for viral replication. This study was designed to include a high number of replicates (48 replicates; 16 biological repeats with 3 technical replicates each) to prevent data instability, remove sources of bias, and allow multifactorial bioinformatic analyses in order to study the resulting interaction network. The results obtained provide an interesting insight into the replication mechanisms of SARS-CoV-2.

Human astroviruses (HAstV) cause gastroenteritis and neurologic disorders. These envelopeless viruses have +ssRNA genomes with three overlapping open reading frames (ORF): ORF1a, ORF1b, and ORF2, flanked by 80-100 nucleotide Untranslated Regions (UTRs). VPg, is a viral protein, covalently linked to the 5’ end of the genome, helps in viral infection. ORF1b encodes nsP1b, an RNA-dependent RNA polymerase (RdRp) involved in the synthesis of genomic RNA. The viral replication complex (VRC) forms within the intracellular membrane during astrovirus replication. To understand HAstV’s role in viral replication and know what other factors are involved, we determine if whether nsP1b is a VRC component and whether it interacts with 5’ and 3’ UTRs of HAstV-8. In this study, we found that recombinant nsP1b interacts with the 5’ and 3’ UTRs using electrophoretic mobility shift and north western blot assays. By confocal microscopy, at 8 hours post infection we found nsP1b near the perinuclear region, where VPg and the cellular protein Calnexin are located, suggesting that these cellular factors are part of the complexes involved in viral replication. We are currently investigating on more detail the possible association of nsP1b with other viral proteins as from CaCo2 cells in the replication of this virus. [ABSTRACT FROM AUTHOR]

Flavivirus consists of a large number of arthropod-borne viruses, many of which cause life-threatening diseases in humans. A characteristic feature of flavivirus infection is to induce the rearrangement of intracellular membrane structure in the cytoplasm. This unique membranous structure called replication organelle is considered as a microenvironment that provides factors required for the activity of the flaviviral replication complex. The replication organelle serves as a place to coordinate viral RNA amplification, protein translation, and virion assembly and also to protect the viral replication complex from the cellular immune defense system. In this review, we summarize the current understanding of how the formation and function of membrane-associated flaviviral replication organelle are regulated by cellular factors.

Pseudorabies virus (PRV) belongs to the Alphaherpesvirinae subfamily and serves as an exceptional animal model for investigating the infection mechanism of Herpes simplex virus type 1. Notably, PRV has the capability to infect a wide range of mammals, including humans, highlighting its potential as an overlooked zoonotic pathogen. The attachment and entry steps of PRV into host cells are crucial to accomplish its life cycle, which involve numerous cellular factors. In this mini review, we offer a comprehensive summary of current researches pertaining to the role of cellular factors in PRV attachment and entry stages, with the overarching goal of advancing the development of novel antiviral agents against this pathogen., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Tan, Wang, Zuo, Shu, Wang and Yao.)

HIV-1 infection of noncycling cells, such as dendritic cells (DCs), is impaired due to limited availability of deoxynucleoside triphosphates (dNTPs), which are needed for HIV-1 reverse transcription. The levels of dNTPs are tightly regulated during the cell cycle and depend on the balance between dNTP biosynthesis and degradation. SAMHD1 potently blocks HIV-1 replication in DCs, although the underlying mechanism is still unclear. SAMHD1 has been reported to be able to degrade dNTPs and viral nucleic acids, which may both hamper HIV-1 reverse transcription. The relative contribution of these activities may differ in cycling and noncycling cells. Here, we show that inhibition of HIV-1 replication in monocyte-derived DCs (MDDCs) is associated with an increased expression of p21cip1/waf, a cell cycle regulator that is involved in the differentiation and maturation of DCs. Induction of p21 in MDDCs decreases the pool of dNTPs and increases the antiviral active isoform of SAMHD1. Although both processes are complementary in inhibiting HIV-1 replication, the antiviral activity of SAMHD1 in our primary cell model appears to be, at least partially, independent of its dNTPase activity. The reduction in the pool of dNTPs in MDDCs appears rather mostly due to a p21-mediated suppression of several enzymes involved in dNTP synthesis (i.e., RNR2, TYMS, and TK-1). These results are important to better understand the interplay between HIV-1 and DCs and may inform the design of new therapeutic approaches to decrease viral dissemination and improve immune responses against HIV-1. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the expressions of toll-like receptor 2 (TLR2), toll-like receptor 4 (TLR4), tumor necrosis factor alpha (TNF-α), IFN-γ (IFN-gamma), interleukin 2 (IL-2), interleukin 6 (IL-6) and interleukin 10 (IL-10) in human immunodeficiency virus (HIV) patients with tuberculosis (TB) infection. Methods: Two groups of HIV patients (68 in each group) were used for this study. These were HIV with TB (HIV/TB) group and HIV without TB group. A third group (68 healthy people) served as control. Quantitative polymerase chain reaction (qPCR) was adopted to measure TLR-2 and TLR-4 expressions in peripheral blood mononuclear cells (PBMC), while the serum levels of TNF-α, IFN-γ, IL-2, IL-6 and IL-10 were determined by ELISA. Results: The ▵ Ct values of TLR-2 and TLR-4 in HIV/TB and HIV groups were significantly lower than those in the control group (p < 0.05). Compared to control group, the serum levels of TNF-α, IL-6 and IL-10 significantly increased, while IFN-γ and IL-2 in HIV/TB and HIV groups significantly decreased (p < 0.05). However, IFN-γ and IL-2 decreased significantly in HIV/TB group (p < 0.05). Expression of TLR2 correlated positively with serum levels of TNF-α, IL-6 and IL-10, but negatively with IFN-γ and IL-2 (p < 0.05). Conclusion: TLR2 signal pathway plays a role in HIV patients with TB infection by promoting the expressions of TNF-α, IL-6 and IL-10, while inhibiting IFN-γ and IL-2 cellular factors, and thus may provide a new pathway for the treatment of patients with HIV/TB. [ABSTRACT FROM AUTHOR]

There are few tumor cell subpopulations with stem cell characteristics in tumor tissue, defined as cancer stem cells (CSCs) or cancer stem-like cells (CSLCs), which can reconstruct neoplasms with malignant biological behaviors such as invasiveness via self-renewal and unlimited generation. The microenvironment that CSCs depend on consists of various cellular components and corresponding medium components. Among these factors existing at a variety of levels and forms, cytokine networks and numerous signal pathways play an important role in signaling transduction. These factors promote or maintain cancer cell stemness, and participate in cancer recurrence, metastasis, and resistance. This review aims to summarize the recent molecular data concerning the multilayered relationship between CSCs and CSC-favorable microenvironments. We also discuss the therapeutic implications of targeting this synergistic interplay, hoping to give an insight into targeting cancer cell stemness for tumor therapy and prognosis., (© 2023 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.)

Cephalopods have the most advanced circulatory and nervous system among the mollusks. Recently, they have been included in the European directive which state that suffering and pain should be minimized in cephalopods used in experimentation. The knowledge about cephalopod welfare is still limited and several gaps are yet to be filled, especially in reference to pathogens, pathologies and immune response of these mollusks. In light of the requirements of the normative, in addition to the ecologic and economic importance of cephalopods, in this review we update the work published to date concerning cephalopod immune system. Significant advances have been reached in relation to the characterization of haemocytes and defensive mechanisms comprising cellular and humoral factors mainly, but not limited, in species of high economic value like Sepia officinalis and Octopus vulgaris . Moreover, the improvement of molecular approaches has helped to discover several immune-related genes/proteins. These immune genes/proteins include antimicrobial peptides, phenoloxidases, antioxidant enzymes, serine protease inhibitor, lipopolysaccharide-induced TNF-α factor, Toll-like receptors, lectins, even clusters of differentiation among others. Most of them have been found in haemocytes but also in gills and digestive gland, and the characterization as well as their precise role in the immune response of cephalopods is still pending to be elucidated. The assessment of immune parameters in cephalopods exposed to contaminants is just starting, but the negative impact of some pollutants on the immune response of the common octopus has been reported. This review summarizes the current status of our knowledge about the cephalopod immune system that seems to be far from simply. On the contrary, the advances gained to date point out a complex innate immunity in cephalopods. [ABSTRACT FROM AUTHOR]

Background: The introduction of C-C chemokine receptor type-5 (CCR5) antagonists as antiretroviral therapy has led to the need to study HIV co-receptor tropism in different HIV-1 subtypes and geographical locations. This study was undertaken to evaluate HIV-1 co-receptor tropism in the developing world where non-B subtypes predominate, in order to assess the therapeutic and prophylactic potential of CCR5 antagonists in these regions. Methods: HIV-1-infected patients were recruited into this prospective, cross-sectional, epidemiologic study from HIV clinics in South Africa, Uganda and India. Patients were infected with subtypes C (South Africa, India) or A or D (Uganda). HIV-1 subtype and co-receptor tropism were determined and analyzed with disease characteristics, including viral load and CD4+ and CD8+ T cell counts. Results: CCR5-tropic (R5) HIV-1 was detected in 96% of treatment-naïve (TN) and treatment-experienced (TE) patients in India, 71% of TE South African patients, and 86% (subtype A/A1) and 71% (subtype D) of TN and TE Ugandan patients. Dual/mixed-tropic HIV-1 was found in 4% of Indian, 25% of South African and 13% (subtype A/ A1) and 29% (subtype D) of Ugandan patients. Prior antiretroviral treatment was associated with decreased R5 tropism; however, this decrease was less in subtype C from India (TE: 94%, TN: 97%) than in subtypes A (TE: 59%; TN: 91%) and D (TE: 30%; TN: 79%). R5 virus infection in all three subtypes correlated with higher CD4+ count. Conclusions: R5 HIV-1 was predominant in TN individuals with HIV-1 subtypes C, A, and D and TE individuals with subtypes C and A. Higher CD4+ count correlated with R5 prevalence, while treatment experience was associated with increased non-R5 infection in all subtypes. [ABSTRACT FROM AUTHOR]

Abstract: Human immunodeficiency virus type 1(HIV-1) infection is the leading cause of death worldwide in adults attributable to infectious diseases. Although the majority of infections are in sub-Saharan Africa and Southeast Asia, HIV-1 is also a major health concern in most countries throughout the globe. While current antiretroviral treatments are generally effective, particularly in combination therapy, limitations exist due to drug resistance occurring among the drug classes. Traditionally, HIV-1 drugs have targeted viral proteins, which are mutable targets. As cellular genes mutate relatively infrequently, host proteins may prove to be more durable targets than viral proteins. HIV-1 replication is dependent upon cellular proteins that perform essential roles during the viral life cycle. Maraviroc is the first FDA-approved antiretroviral drug to target a cellular factor, HIV-1 coreceptor CCR5, and serves to intercept viral–host protein–protein interactions mediating entry. Recent large-scale siRNA and shRNA screens have revealed over 1000 candidate host factors that potentially support HIV-1 replication, and have implicated new pathways in the viral life cycle. These host proteins and cellular pathways may represent important targets for future therapeutic discoveries. This review discusses critical cellular factors that facilitate the successive steps in HIV-1 replication. [Copyright &y& Elsevier]

Abstract: Two oligodeoxynucleotides (ODNs) were found to have a strong inhibition on the hepatitis C virus (HCV) internal ribosomal entry sites (IRES)-mediated translation but not the rabbit globin mRNA translation. Specific inhibition of those ODNs on HCV IRES-mediated translation was confirmed with heat treatment of ODNs in formic acid and dosage-dependent manners. Heat treatment of ODNs presented a decreasing inhibitory effect on HCV IRES-mediated translation. A dosage-dependent decrease of HCV IRES-mediated translation was observed with increasing amount of these ODNs in HeLa cell extracts. The minimal sequences of ODNs (A11) were identified as 5′-CGCGTTACG-3′ with the strongest inhibition of the HCV IRES-mediated translation. In a search for cellular factors, two cellular factors (p68 and p70) were identified to interact with ODNs A1 and A11, but not A5 (CT-oligo). This data showed new kinds of cellular proteins involved in HCV IRES-mediated translation. Further study of ODNs and these cellular proteins will provide important information for understanding the mechanistic basis and molecular regulation of HCV IRES-mediated translation. [Copyright &y& Elsevier]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the recently emerged virus responsible for the COVID-19 pandemic. Clinical presentation can range from asymptomatic disease and mild respiratory tract infection to severe disease with lung injury, multiorgan failure, and death. SARS-CoV-2 is the third animal coronavirus to emerge in humans in the 21st century, and coronaviruses appear to possess a unique ability to cross borders between species and infect a wide range of organisms. This is somewhat surprising as, except for the requirement of host cell receptors, cell–pathogen interactions are usually species-specific. Insights into these host–virus interactions will provide a deeper understanding of the process of SARS-CoV-2 infection and provide a means for the design and development of antiviral agents. In this study, we describe a complex analysis of SARS-CoV-2 infection using a genome-wide CRISPR-Cas9 knock-out system in HeLa cells overexpressing entry receptor angiotensin-converting enzyme 2 (ACE2). This platform allows for the identification of factors required for viral replication. This study was designed to include a high number of replicates (48 replicates; 16 biological repeats with 3 technical replicates each) to prevent data instability, remove sources of bias, and allow multifactorial bioinformatic analyses in order to study the resulting interaction network. The results obtained provide an interesting insight into the replication mechanisms of SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Two mutant Rat2 fibroblast cell lines, R3-2 and R4-7, have been previously isolated by a selection for retrovirus resistance. We have now further analyzed the basis of the block to retroviral infection in the R3-2 line. Using Affymetrix GeneChip analysis, several genes were identified as differentially expressed in the mutant R3-2 line compared with the wild-type cells. One of the candidate gene products, FEZ1 (fasciculation and elongation protein ζ-1), a protein kinase C (PKC)ζ-interacting protein homologous to the Caenorhabditis elegans synaptic transport protein UNC-76, was found to be up-regulated >30-fold in the resistant R3-2 line. FEZ1 overexpression in Rat2 cells conferred a potent resistance to infection by genetically marked retroviruses, and the degree of retroviral resistance in both Rat2 fibroblasts and 293T cells tightly correlated with the expression level of FEZ1 transcripts. FEZ1-overexpressing Rat2 cells showed a similar phenotype to that of the mutant R3-2 line: Infection resulted in normal viral DNA synthesis but a reduction in the formation of circular DNA, indicating a block after reverse transcription but before nuclear entry. Partial knockdown of FEZ1 expression in R3-2 by RNA interference (RNAi) significantly reduced the resistance of this line to infection. Thus, our data suggest that FEZ1 overexpression is sufficient to explain the resistant phenotype of R3-2 cells and identify FEZ1 as a new gene capable of causing retrovirus resistance. [ABSTRACT FROM AUTHOR]

Background: Pleural mesothelioma is a deadly asbestos induced cancer. Less than 10% of mesothelioma patients survive 5 years post diagnosis. However survival can range from a few months to a number of years. Accurate prediction of survival is important for patients to plan for their remaining life, and for clinicians to determine appropriate therapy. One unusual feature of mesothelioma is that patients frequently present with tumor-associated pleural effusions early in the course of the disease., Objective: To study whether cells and molecules present in pleural effusions provide prognostic information for mesothelioma., Methods: We profiled the cellular constituents and concentrations of 40 cytokines, chemokines and cellular factors (collectively "soluble factors") involved in inflammatory and immune signalling pathways in pleural effusion samples from 50 mesothelioma patients.Associations with survival were evaluated by Cox proportional hazards regression methods. Results for the two soluble factors most significantly and independently associated with survival were validated in an independent set of samples (n= 51) using a separate assay system., Results: Survival analysis revealed that IL8, IL2Ra (CD25) and PF4 were independent determinants of a more negative prognosis in mesothelioma patients, independent of other known prognostic factors. Lipocalin2 and IL4 were associated with better prognosis., Conclusions: This study demonstrates that pleural effusions rich in a range of soluble factors are associated with poor prognosis. These findings will enhance our ability to prognosticate outcomes in mesothelioma patients.

ABSTRACT Enterovirus A71 (EV-A71) can cause hand, foot and mouth disease with neurological and systemic complications, most frequently affecting children and infants. We describe a cis- acting replication element ( cre ) with a conserved stem-loop structure within the EV-A71 2C-coding region. By site-directed mutagenesis and reverse genetics using the EV-A71 full-length genome and the EV-A71 replicon containing the firefly luciferase reporter gene in place of the P1 region, the stem-loop structure and the AAACA in the loop of the cre were confirmed to be required for the EV-A71 replication phenotype. EV-A71 genomes containing a mutation at the first or third A residue of AAACA could not be recovered. Insertion of a wild-type cre from EV-A71 or poliovirus in the 5'UTR led to successful recovery of the replication of nonviable mutants. Furthermore, the cre mutants showed lower binding capacity with the host cellular factor IGF2BP2, knockdown of which resulted in a significant decrease in EV-A71 production. All the available evidence shows the location independence but functional importance of the interaction of the cre with the cellular host for efficient production of EV-A71, contributing to the growing body of knowledge regarding picornavirus cre s.

Flavivirus consists of a large number of arthropod-borne viruses, many of which cause life-threatening diseases in humans. A characteristic feature of flavivirus infection is to induce the rearrangement of intracellular membrane structure in the cytoplasm. This unique membranous structure called replication organelle is considered as a microenvironment that provides factors required for the activity of the flaviviral replication complex. The replication organelle serves as a place to coordinate viral RNA amplification, protein translation, and virion assembly and also to protect the viral replication complex from the cellular immune defense system. In this review, we summarize the current understanding of how the formation and function of membrane-associated flaviviral replication organelle are regulated by cellular factors. [ABSTRACT FROM AUTHOR]

Ebola and Marburg viruses cause outbreaks of highly lethal infection in central Africa. In the last few years, rapid progress has been made in understanding how these viruses are transmitted and spread. These studies show that the glycoprotein GP that protrudes from the virus envelope mediates membrane fusion and infection. Activation of the GP membrane fusion activity is triggered by a multi-step pathway initiated by binding to lectins expressed on the cell surface. After uptake of lectin-bound particles by macropinocytosis, virus-containing vesicles are transported to late endosomes and lysosomes containing the protease cathepsin B and the membrane protein Niemann-Pick C1 (NPC1), which are essential for infection. Recent studies indicate that cathepsin B cleaves GP, removing heavily glycosylated sequences and exposing the domain in GP that is a ligand for NPC1. Although more studies are needed, current evidence strongly suggests that binding of protease-cleaved GP to NPC1 is the signal that activates virus membrane fusion and infection. Importantly, small molecules that target NPC1 and interfere with GP binding and ebolavirus infection have been identified. A major goal is to develop these inhibitors into anti-viral drugs.

Macrophages are cells of the immune system that, with T lymphocytes, are major target for HIV, the pathogen responsible for AIDS. Macrophages play a relevant role in the pathogenesis of the infection, from the entry of the virus through the mucosa to its spreading in body tissues, especially the central nervous system, and contribute to the formation of viral reservoirs. The replication of HIV in macrophages presents similarities but also some differences compared to that in lymphocytes, and requires a number of interactions between viral and host proteins essential for each step of the viral cycle. Nevertheless, many cellular proteins act as restriction factors against the virus, inhibiting different phases of its replication. In this review, we summarise the up-to-date knowledge of the replication cycle of HIV in macrophages and we describe the key role of certain cellular factors implicated in the control of its replication specifically in these cells.