Virus Infection and Death Receptor-Mediated Apoptosis

Pathogen-induced apoptosis in echinoderms: A review

Echinoderms possess unique biological traits that make them valuable models in immunology, regeneration, and developmental biology studies. As a class rich in active substances with significant nutritional and medicinal value, echinoderms face threats from marine pathogens, including bacteria, viruses, fungi, protozoa, and parasites, which have caused substantial economic losses in echinoderm aquaculture. Echinoderms counteract pathogen invasion through innate immunity and programmed cell death, in particular, with apoptosis being essential for eliminating infected or damaged cells and maintaining homeostasis in many echinoderm cell types. Despite the importance of this process, there is a lack of comprehensive and updated reviews on this topic. This review underscores that echinoderm apoptotic pathways exhibit a complexity comparable to that of vertebrates, featuring proteins with unique domains that may indicate the presence of novel signaling mechanisms. We synthesize current knowledge on how echinoderms utilize diverse transcriptional and post-transcriptional mechanisms to regulate apoptosis in response to pathogen infections and explore how pathogens have evolved strategies to manipulate echinoderm apoptosis, either by inhibiting it to create survival niches or by inducing excessive apoptosis to weaken the host. By elucidating the primary apoptotic pathways in echinoderms and the host-pathogen interactions that modulate these pathways, this review aims to reveal new mechanisms of apoptosis in animal immune defense and provide insights into the evolutionary arms race between hosts and pathogens.

Screening the effective components of Lysionotus pauciflorus Maxim. on the treatment of LPS induced acute lung injury mice by integrated UHPLC-Q-TOF-MS/MS and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Acute lung injury (ALI) is an inflammatory reaction produced through various injury-causing factors acting on the lungs in a direct or indirect way, with a high morbidity and mortality rate. A review of clinical experience has revealed that Lysionotus pauciflorus Maxim (LP) has a significant therapeutic effect on ALI. However, the comprehensive effective components of LP are uncertain, and the mechanisms, especially the potential therapeutic target for anti-ALI, are still unknown.

AIMS OF THE STUDY

In vitro and in vivo validation of the pharmacodynamics of LP in the treatment of ALI and exploration of its potential mechanism of action based on network pharmacology, molecular docking and experimental validation.

MATERIALS AND METHODS

Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was employed to identify the ingredients of LP extracts. The potential bioactive ingredients, key targets and signalling pathways were identified by network pharmacology, based on the results of the mass spectrometry analysis. Subsequently, molecular docking was performed on the screened core components and key targets to calculate their molecular binding energies and binding potentials, and to explore the mutual binding modes of small-molecule ligands and large-molecule proteins. Finally, lipopolysaccharide (LPS)-induced RAW264.7 cell model and ALI mice model were used to validate the therapeutic effects and potential mechanism of LP extract towards ALI.

RESULTS

From the mass spectrometry results of LP extracts, a total of 89 chemical components were identified, including 46 phenylethanol glycosides, 26 flavonoids, 9 organic acids and their derivatives and 8 other compounds. And furthermore 39 core active components were screened by network pharmacology. The top 10 core components (4 phenylethanol glycosides, 6 flavonoids) have been screened in the composition -target-disease network, and 37 core targets related to LP efficacy were obtained by fitting PPI network analysis. 10 signalling pathways and their targets associated with LP treatment of ALI were obtained by GO/KEGG analysis, indicating that LP could regulate TLR4 and NF-κB signalling pathways through 4 key targets, namely NFKB1, RELA, TLR4 and TNF. The results of the molecular docking procedure indicated a strong affinity, with the binding energies between each component and the target site being less than -6 kcal/mol. The binding modes included Hydrogen Bonds, Pi-Pi interaction, Hydrophobic Interactions, Salt Bridges, Pi-cation interactions. These observations were subsequently validated in vitro and in vivo experiments. The outcomes of in vitro and in vivo experiments demonstrated that LP was effective in reducing the infiltration of inflammatory bacteria in lung tissues and attenuated the expression of pro-inflammatory cytokines in LPS-stimulated mice bronchoalveolar lavage fluid (BALF) and RAW264.7 cells. Furthermore, LP inhibited the expression and phosphorylation of TLR4 protein and NF-κB protein, thus playing a role in the prevention of ALI.

CONCLUSIONS

In this study, mass spectrometry analysis was combined with biomolecular networks to initially elucidate the potential of LP to treat ALI by modulating the TLR4/NF-κB pathway. This offers a definitive experimental basis for the development of new LP drugs.

Transcriptomic analysis reveals bovine herpesvirus 1 infection regulates innate immune response resulted in restricted viral replication in neuronal cells

BACKGROUND

Bovine herpesvirus 1 (BoHV-1) is a major pathogen that affects the global bovine population, primarily inducing respiratory and reproductive disorders. Its ability to establish latent infections in neuronal cells and to reactivate under certain conditions poses a continual threat to uninfected hosts. In this study, we aimed to analyze the replication characteristics of BoHV-1 in neuronal cells, as well as the effects of viral replication on host cell immunity and physiology.

METHODS

Using the Neuro-2a neuronal-origin cell line as a model, we explored the dynamics of BoHV-1 replication and analyzed differential gene expression profiles post-BoHV-1 infection using high-throughput RNA sequencing.

RESULTS

BoHV-1 demonstrated restricted replication in Neuro-2a cells. BoHV-1 induced apoptotic pathways and enhanced the transcription of interferon-stimulated genes and interferon regulatory factors while suppressing the complement cascade in Neuro-2a cells.

CONCLUSIONS

Different from BoHV-1 infection in other non-highly differentiated somatic cells result in viral dominance, BoHV-1 regulated the innate immune response in neuronal cells formed a "virus-nerve cell" relative equilibrium state, which may account for the restricted replication of BoHV-1 in neuronal cells, leading to a latent infection. These findings provide a foundation for further research into the mechanism underlying BoHV-1-induced latent infection in nerve cells.

PEG-SeNPs as therapeutic agents inhibiting apoptosis and inflammation of cells infected with H1N1 influenza A virus

The rapid variation of influenza challenges vaccines and treatments, which makes an urgent task to develop the high-efficiency and low-toxicity new anti-influenza virus drugs. Selenium is one of the essential trace elements for the human body that possesses a good antiviral activity. In this study, we assessed anti-influenza A virus (H1N1) activity of polyethylene glycol (PEG)-modified gray selenium nanoparticles (PEG-SeNPs) on Madin-Darby Canine Kidney (MDCK) cells in vitro. CCK-8 assay showed that PEG-SeNPs had a protective effect on H1N1-infected MDCK cells. Moreover, PEG-SeNPs significantly reduced the mRNA level of H1N1. TUNEL-DAPI test showed that DNA damage reached a high level but effectively prevented after PEG-SeNPs treatment. Meanwhile, JC-1, Annexin V-FITC and cell cycle assay demonstrated the apoptosis induced by H1N1 was reduced greatly when treated with PEG-SeNPs. Furthermore, the downregulation of p-ATM, p-ATR and P53 protein, along with the upregualation of AKT protein indicated that PEG-SeNPs could inhibit H1N1-induced cell apoptosis through reactive oxygen species (ROS)-mediated related signaling pathways. Finally, Cytokine detection demonstrated PEG-SeNPs inhibited the production of pro-inflammatory factors after infection, including IL-1β, IL-5, IL-6, and TNF-α. To sum up, PEG-SeNPs might become a new potential anti-H1N1 influenza virus drug due to its antiviral and anti-inflammatory activity.

MicroRNA dysregulation and its impact on apoptosis-related signaling pathways in myelodysplastic syndrome

Myelodysplastic syndrome (MDS) holds a unique position among blood cancers, encompassing a spectrum of blood-related disorders marked by impaired maturation of blood cell precursors, bone marrow abnormalities, genetic instability, and a higher likelihood of progressing to acute myeloid leukemia. MicroRNAs (miRNAs), short non-coding RNA molecules typically 18-24 nucleotides in length, are known to regulate gene expression and contribute to various biological processes, including cellular differentiation and programmed cell death. Additionally, miRNAs are involved in many aspects of cancer development, influencing cell growth, transformation, and apoptosis. In this study, we explore the impact of microRNAs on cellular apoptosis in MDS.

Unveiling the Antiviral Potential of Minocycline: Modulation of Nuclear Export of Viral Ribonuclear Proteins during Influenza Virus Infection

Influenza A virus (IAV) poses a global threat worldwide causing pandemics, epidemics, and seasonal outbreaks. Annual modification of vaccines is costly due to continual shifts in circulating genotypes, leading to inadequate coverage in low- and middle-income countries like India. Additionally, IAVs are evolving resistance to approved antivirals, necessitating a search for alternative treatments. In this study, the antiviral role of the FDA-approved antibiotic minocycline against IAV strains was evaluated in vitro and in vivo by quantifying viral gene expression by qRT-PCR, viral protein levels by Western blotting, and viral titers. Our findings demonstrate that minocycline at a non-toxic dose effectively inhibits IAV replication, regardless of viral strain or cell line. Its antiviral mechanism operates independently of interferon signaling by targeting the MEK/ERK signaling pathway, which is crucial for the export of viral ribonucleoproteins (vRNPs). Minocycline prevents the assembly and release of infectious viral particles by causing the accumulation of vRNPs within the nucleus. Moreover, minocycline also inhibits IAV-induced late-stage apoptosis, further suppressing viral propagation. The antiviral activity of minocycline against IAVs could offer a promising solution amidst the challenges posed by influenza and the limitations of current treatments.

Bergamottin Inhibits Bovine Viral Diarrhea Virus Replication by Suppressing ROS-Mediated Endoplasmic Reticulum Stress and Apoptosis

Bovine viral diarrhea virus (BVDV) is one of the most important etiological agents that causes serious economic losses to the global livestock industry. Vaccines usually provide limited efficacy against BVDV due to the emergence of mutant strains. Therefore, developing novel strategies to combat BVDV infection is urgently needed. Bergamottin (Berg), a natural furanocoumarin compound, possesses various pharmaceutical bioactivities, but its effect on BVDV infection remains unknown. The present study aimed to investigate the antiviral effect and underlying mechanism of Berg against BVDV infection. The results showed that Berg exhibited an inhibitory effect on BVDV replication in MDBK cells by disrupting the viral replication and release, rather than directly inactivating virus particles. Mechanistically, Berg inhibits BVDV replication by suppressing endoplasmic reticulum (ER) stress-mediated apoptosis via reducing reactive oxygen species (ROS) generation. Studies in vivo demonstrated that oral gavage of Berg at doses of 50 mg/kg and 75 mg/kg significantly reduced the viral load within the intestines and spleen in BVDV-challenged mice. Furthermore, histopathological damage and oxidative stress caused by BVDV were also mitigated with Berg treatment. Our data indicated that Berg suppressed BVDV propagation both in vitro and in vivo, suggesting it as a promising antiviral option against BVDV.

Identification of a novel caspase cleavage motif AEAD

Infections of many viruses induce caspase activation to regulate multiple cellular pathways, including programmed cell death, immune signaling and etc. Characterizations of caspase cleavage sites and substrates are important for understanding the regulation mechanisms of caspase activation. Here, we identified and analyzed a novel caspase cleavage motif AEAD, and confirmed its caspase dependent cleavage activity in natural substrate, such as nitric oxide-associated protein 1 (NOA1). Fusing the enhanced green fluorescent protein (EGFP) with the mitochondrial marker protein Tom20 through the AEAD motif peptide localized EGFP to the mitochondria. Upon the activation of caspase triggered by Sendai virus (SeV) or herpes simplex virus type 1 (HSV-1) infection, EGFP diffusely localized to the cell due to the caspase-mediated cleavage, thus allowing visual detection of the virus-induced caspase activation. An AEAD peptide-derived inhibitor Z-AEAD-FMK were developed, which significantly inhibited the activities of caspases-1, -3, -6, -7, -8 and -9, exhibiting a broad caspase inhibition effect. The inhibitor further prevented caspases-mediated cleavage of downstream substrates, including BID, PARP1, LMNA, pro-IL-1β, pro-IL-18, GSDMD and GSDME, protecting cells from virus-induced apoptotic and pyroptotic cell death. Together, our findings provide a new perspective for the identification of novel caspase cleavage motifs and the development of new caspase inhibitors and anti-inflammatory drugs.

Singapore grouper iridovirus VP146 modulates the cGAS-STING signaling pathway to escape the interferon immune response

Singapore grouper iridovirus (SGIV) is a large double-stranded DNA virus that has caused significant economic losses to the grouper aquaculture industry. So far, the structure and function of SGIV proteins have been successively reported. In the present paper, the protein of SGIV VP146 was cloned and identified. VP146 was whole-cell distributed in GS cells. VP146 promoted SGIV replication and inhibited the transcription of interferon-related genes as well as pro-inflammatory cytokines in GS cells. In addition, VP146 was involved in the regulation of the cGAS-STING signaling pathway, and decreased cGAS-STING induced the promoter of ISRE and NF-κB. VP146 interacted with the proteins of cGAS, STING, TBK1, and IRF3 from grouper, but did not affect the binding of grouper STING to grouper TBK1 and grouper IRF3. Interestingly, grouper STING was able to affect the intracellular localization of VP146. Four segment structural domains of grouper STING were constructed, and grouper STING-CTT could affect the intracellular localization of VP146. VP146 had no effect on the self-binding of EcSITNG, nor on the binding of EcSTING to EcTBK1 and EcIRF3. Together, the results demonstrated that SGIV VP146 modulated the cGAS-STING signaling pathway to escape the interferon immune response.

Advancements in precision nanomedicine design targeting the anoikis-platelet interface of circulating tumor cells

Tumor metastasis, the apex of cancer progression, poses a formidable challenge in therapeutic endeavors. Circulating tumor cells (CTCs), resilient entities originating from primary tumors or their metastases, significantly contribute to this process by demonstrating remarkable adaptability. They survive shear stress, resist anoikis, evade immune surveillance, and thwart chemotherapy. This comprehensive review aims to elucidate the intricate landscape of CTC formation, metastatic mechanisms, and the myriad factors influencing their behavior. Integral signaling pathways, such as integrin-related signaling, cellular autophagy, epithelial-mesenchymal transition, and interactions with platelets, are examined in detail. Furthermore, we explore the realm of precision nanomedicine design, with a specific emphasis on the anoikis‒platelet interface. This innovative approach strategically targets CTC survival mechanisms, offering promising avenues for combatting metastatic cancer with unprecedented precision and efficacy. The review underscores the indispensable role of the rational design of platelet-based nanomedicine in the pursuit of restraining CTC-driven metastasis.

Survivin: A key apoptosis inhibitor in COVID-19 infection and its implication for treatment protocol

While the relationship between cellular apoptosis and proliferation rates in COVID patients remains underexplored in existing literature, various viruses are known to impact these fundamental process to modulate response to infection. This paper aims to assess apoptosis and proliferation rates in individuals recently infected with Coronavirus, both before and after vaccination, comparing them with healthy controls. Peripheral blood cells from newly diagnosed COVID-19 patients revealed a significant increase in proliferation and apoptosis levels in fresh lymphocytes and granulocytes compared to healthy donors. Notably, as none of the patients were under corticosteroid therapy or cytotoxic drugs, the study underscores the critical role of white blood (WBC) apoptosis in viral pathogenesis, potentially contributing significantly to COVID-19's pathogenicity. Elevated levels of soluble Fas ligand (FaSL) and the pro-inflatmmatory cytokine IL-38 were identified in COVID-19 patients, indicating potential immune dysregulation. Furthermore, individual who received the vaccine or recovered from COVID-19 exhibited higher survivin rates, suggesting a protective role for survivin in migitating lung damage. These findings suggest the prospect of developing a strategy to prevent WBC apoptosis, offering potential benefits in averting lymphopenia associated with severe COVID-19 ouctomes.

Avian Coronavirus Infectious Bronchitis Virus Activates Mitochondria-Mediated Apoptosis Pathway and Affects Viral Replication by Inducing Reactive Oxygen Species Production in Chicken HD11 Cells

Infectious bronchitis virus (IBV), a coronavirus that causes severe respiratory and gastrointestinal illness in poultry, leads to substantial economic losses. According to earlier research, IBV infection causes chicken macrophage HD11 cells to undergo cell apoptosis. Reactive oxygen species (ROS) and the IBV-activated intrinsic apoptotic signaling pathway were examined in this work. The findings demonstrate that IBV infection causes ROS to accumulate. Moreover, IBV infection decreased the mitochondrial transmembrane potential in HD11 cells, which could be blocked by ROS antioxidants (PDTC and NAC). The two antioxidants significantly affected the expression of Bcl-2 and Bax and further inhibited the activation of caspase-3 and apoptosis in HD11 cells. Additionally, IBV replication was decreased by blocking ROS accumulation. Pretreating HD11 cells with ammonium chloride (NH4Cl) prevented IBV from entering the cells and reduced the oxidative stress which IBV causes. The ability to accumulate ROS was also lost in UV-inactivated IBV. The IBV N protein induces cell apoptosis through the activation of ROS. These findings provide an explanation for the processes of IBV infection in immune cells by indicating that IBV-induced ROS generation triggers cell apoptosis in HD11 cells.

Caspase-mediated AURKA cleavage at Asp132 is essential for paclitaxel to elicit cell apoptosis

Background: Aurora kinase A (AURKA) is a potent oncogene that is often aberrantly expressed during tumorigenesis, and is associated with chemo-resistance in various malignancies. However, the role of AURKA in chemo-resistance remains largely elusive. Methods: The cleavage of AURKA upon viral infection or apoptosis stimuli was assesed by immunoblotting assays in several cancer cells or caspase deficient cell line models. The effect of AURKA cleavage at Asp132 on mitosis was explored by live cell imaging and immunofluorescence staining experiments. The role of Asp132-cleavage of AURKA induced by the chemotherapy drug paclitaxel was investigated using TUNEL, immunohistochemistry assay in mouse tumor xenograft model and patient tissues. Results: The proteolytic cleavage of AURKA at Asp132 commonly occurs in several cancer cell types, regardless of viral infection or apoptosis stimuli. Mechanistically, caspase 3/7/8 cleave AURKA at Asp132, and the Asp132-cleaved forms of AURKA promote cell apoptosis by disrupting centrosome formation and bipolar spindle assembly in metaphase during mitosis. The AURKAD132A mutation blocks the expression of cleaved caspase 3 and EGR1, which leads to reduced therapeutic effects of paclitaxel on colony formation and malignant growth of tumor cells in vitro and in vivo using a murine xenograft model and cancer patients. Conclusions: This study reveals that caspase-mediated AURKAD132 proteolysis is essential for paclitaxel to elicit cell apoptosis and indicates that AURKAD132 is a potential key target for chemotherapy.

Apoptotic and non-apoptotic roles of caspases in placenta physiology and pathology

Caspases, a family of cysteine proteases, are pivotal regulators of apoptosis, the tightly controlled cell death process crucial for eliminating excessive or unnecessary cells during development, including placental development. Collecting research has unveiled the multifaceted roles of caspases in the placenta, extending beyond apoptosis. Apart from their involvement in placental tissue remodeling via apoptosis, caspases actively participate in essential regulatory processes, such as trophoblast fusion and differentiation, significantly influencing placental growth and functionality. In addition, growing evidence indicates an elevation in caspase activity under pathological conditions like pre-eclampsia (PE) and intrauterine growth restriction (IUGR), leading to excessive cell death as well as inflammation. Drawing from advancements in caspase research and placental development under both normal and abnormal conditions, we examine the significance of caspases in both cell death (apoptosis) and non-cell death-related processes within the placenta. We also discuss potential therapeutics targeting caspase-related pathways for placenta disorders.

Indirect CD4+ T cell protection against mouse gamma-herpesvirus infection via interferon gamma

CD4+ T cells play a key role in γ-herpesvirus infection control. However, the mechanisms involved are unclear. Murine herpesvirus type 4 (MuHV-4) allows relevant immune pathways to be dissected experimentally in mice. In the lungs, it colonizes myeloid cells, which can express MHC class II (MHCII), and type 1 alveolar epithelial cells (AEC1), which lack it. Nevertheless, CD4+ T cells can control AEC1 infection, and this control depends on MHCII expression in myeloid cells. Interferon-gamma (IFNγ) is a major component of CD4+ T cell-dependent MuHV-4 control. Here, we show that the action of IFNγ is also indirect, as CD4+ T cell-mediated control of AEC1 infection depended on IFNγ receptor (IFNγR1) expression in CD11c+ cells. Indirect control also depended on natural killer (NK) cells. Together, the data suggest that the activation of MHCII+ CD11c+ antigen-presenting cells is key to the CD4+ T cell/NK cell protection axis. By contrast, CD8+ T cell control of AEC1 infection appeared to operate independently.

IMPORTANCE

CD4+ T cells are critical for the control of gamma-herpesvirus infection; they act indirectly, by recruiting natural killer (NK) cells to attack infected target cells. Here, we report that the CD4+ T cell/NK cell axis of gamma-herpesvirus control requires interferon-γ engagement of CD11c+ dendritic cells. This mechanism of CD4+ T cell control releases the need for the direct engagement of CD4+ T cells with virus-infected cells and may be a common strategy for host control of immune-evasive pathogens.

Evolution of innate immunity: lessons from mammalian models shaping our current view of insect immunity

The innate immune system, a cornerstone for organismal resilience against environmental and microbial insults, is highly conserved across the evolutionary spectrum, underpinning its pivotal role in maintaining homeostasis and ensuring survival. This review explores the evolutionary parallels between mammalian and insect innate immune systems, illuminating how investigations into these disparate immune landscapes have been reciprocally enlightening. We further delve into how advancements in mammalian immunology have enriched our understanding of insect immune responses, highlighting the intertwined evolutionary narratives and the shared molecular lexicon of immunity across these organisms. Therefore, this review posits a holistic understanding of innate immune mechanisms, including immunometabolism, autophagy and cell death. The examination of how emerging insights into mammalian and vertebrate immunity inform our understanding of insect immune responses and their implications for vector-borne disease transmission showcases the imperative for a nuanced comprehension of innate immunity's evolutionary tale. This understanding is quintessential for harnessing innate immune mechanisms' potential in devising innovative disease mitigation strategies and promoting organismal health across the animal kingdom.

Natural Killer Cells and Cytotoxic T Cells: Complementary Partners against Microorganisms and Cancer

Natural killer (NK) cells and cytotoxic T (CD8+) cells are two of the most important types of immune cells in our body, protecting it from deadly invaders. While the NK cell is part of the innate immune system, the CD8+ cell is one of the major components of adaptive immunity. Still, these two very different types of cells share the most important function of destroying pathogen-infected and tumorous cells by releasing cytotoxic granules that promote proteolytic cleavage of harmful cells, leading to apoptosis. In this review, we look not only at NK and CD8+ T cells but also pay particular attention to their different subpopulations, the immune defenders that include the CD56+CD16dim, CD56dimCD16+, CD57+, and CD57+CD16+ NK cells, the NKT, CD57+CD8+, and KIR+CD8+ T cells, and ILCs. We examine all these cells in relation to their role in the protection of the body against different microorganisms and cancer, with an emphasis on their mechanisms and their clinical importance. Overall, close collaboration between NK cells and CD8+ T cells may play an important role in immune function and disease pathogenesis. The knowledge of how these immune cells interact in defending the body against pathogens and cancers may help us find ways to optimize their defensive and healing capabilities with methods that can be clinically applied.

Antitumor effects of polysaccharides from medicinal lower plants: A review

Cancer is one of the leading causes of death worldwide, yet the drugs currently approved for cancer treatment are associated with significant side effects, making it urgent to develop alternative drugs with low side effects. Polysaccharides are natural polymers with ketone or aldehyde groups, which are widely found in plants and have various biological activities such as immunomodulation, antitumor and hypolipidemic. The lower plants have attracted much attention for their outstanding anticancer effects, and many studies have shown that medicinal lower plant polysaccharides (MLPPs) have antitumor activity against various cancers and are promising alternatives with potential development in the food and pharmaceutical fields. Therefore, this review describes the structure and mechanism of action of MLPPs with antitumor activity. In addition, the application of MLPPs in cancer treatment is discussed, and the future development of MLPPs is explored.

KCMF1-like suppresses white spot syndrome virus infection by promoting apoptosis in mud crab (Scylla paramamosain)

Potassium channel modulatory factor 1 (KCMF1), an E3 ubiquitin ligase, plays a vital role in renal tubulogenesis, preeclampsia, and tumor development in mammals. Nevertheless, the function of KCMF1 in invertebrates remains to be investigated. Here, we identified KCMF1-like from Scylla paramamosian, encoding 242 amino acids with two zinc finger domains at the N-terminal. Real-time quantitative PCR analysis revealed that KCMF1-like was expressed in all tested tissues, including hemocytes, brain, mid-intestine, subcuticular epidermis, gills, muscle, heart, and stomach, with higher levels in muscle and mid-intestine. KCMF1-like was up-regulated in the hemocytes of mud crabs challenged with white spot syndrome virus (WSSV). RNA interference (RNAi) was performed to investigate the impact of KCMF1-like on the proliferation of WSSV in mud crabs. Knock-down of KCMF1-like resulted in an increase of the WSSV copy number and an impairment of the hemocytes apoptosis rate in vivo. In addition, KCMF1-like could also affect the mitochondrial membrane potential. Collectively, these results revealed that KCMF1-like might play a crucial role in the defense against virus infection in mud crab. This study contributes a novel insight into the role of KCMF1-like in the antiviral immune defense mechanism in crustaceans.

CBFβ is induced by spring viremia of carp virus and promotes virus replication in zebrafish

The core binding factor subunit beta (CBFβ) is a transcription factor that forms a complex with virial proteins to promote viral infection. In this study, we identified a CBFβ homolog from zebrafish (zfCBFβ) and characterized the biological activity. The deduced zfCBFβ protein was highly similar to orthologs from other species. The zfcbfβ gene was constitutively expressed in tissues and was induced in immune tissues after infection with spring viremia carp virus (SVCV) and stimulation with poly(I:C). Interestingly, zfcbfβ is not induced by type I interferons. Overexpression of zfcbfβ induced tnfα expression but inhibited isg15 expression. Also, overexpression of zfcbfβ significantly increased SVCV titer in the EPC cells. Co-immunoprecipitation assay revealed that zfCBFβ interacts with SVCV phosphoprotein (SVCVP) and host p53, resulting in the increased stability of zfCBFβ. Our results provide evidence that CBFβ is targeted by virus to suppress host antiviral response.

Andrographolide inhibits infectious bronchitis virus-induced apoptosis, pyroptosis, and inflammation

BACKGROUND

Avian infectious bronchitis virus (IBV), a coronavirus, causes a huge economic loss to the poultry industry. Andrographolide (APL) is a compound with a variety of pharmacological properties, including antiviral and anti-inflammatory effects. In this study, APL was evaluated for antiviral activity by its anti-apoptotic, anti-pyroptosis, and anti-inflammatory effects.

METHODS

The cytotoxicity of APL was determined by the MTT method. We investigated the therapeutic impact of APL on IBV through a plate assay. We explored that APL inhibited IBV-induced apoptosis, pyroptosis, and inflammation in HD11 cells by RT-qPCR and immunofluorescence. Also, it was verified in the clinical chicken embryo trial.

RESULTS

We found that APL down-regulated apoptosis-related genes Caspase-3, Caspase-8, Caspase-9, Bax, Bid, and Bak, down-regulated pyroptosis gene DFNA5, and down-regulated inflammation-related genes (NF-κB, NLRP3, iNOS, TNF-α, and IL-1β). In addition, APL reduced the reactive oxygen species (ROS) production in cells. Finally, clinical trials showed that APL inhibited IBV-induced apoptosis, pyroptosis, and inflammation, as well as reduced the mortality and malformation of chicken embryos.

CONCLUSIONS

In this study, we delved into the antiviral properties of APL in the context of chicken macrophage (HD11) infection with IBV. Our findings confirm that andrographolide effectively inhibits apoptosis, pyroptosis, and inflammation by IBV infection. Furthermore, this inhibition was verified on chicken embryos in vivo. This inhibition suggests a substantial potential for APL as a therapeutic agent to mitigate the harmful effects of IBV on host cells.

The tumor suppressive effect and apoptotic mechanism of TRAIL gene-containing recombinant NDV in TRAIL-resistant colorectal cancer HT-29 cells and TRAIL-nonresistant HCT116 cells, with each cell bearing a mouse model

BACKGROUND

TRAIL is an anticancer drug that induces cancer cell apoptosis by interacting with death receptors (DRs). However, owing to low cell-surface expression of DRs, certain colorectal cancer (CRC) cells resist TRAIL-induced apoptosis. Newcastle disease virus (NDV) infection can elevate DR protein expression in cancer cells, potentially influencing their TRAIL sensitivity. However, the precise mechanism by which NDV infection modulates DR expression and impacts TRAIL sensitivity in cancer cells remains unknown.

METHODS

Herein, we developed nonpathogenic NDV VG/GA strain-based recombinant NDV (rNDV) and TRAIL gene-containing rNDV (rNDV-TRAIL). We observed that viral infections lead to increased DR and TRAIL expressions and activate signaling proteins involved in intrinsic and extrinsic apoptosis pathways. Experiments were conducted in vitro using TRAIL-resistant CRC cells (HT-29) and nonresistant CRC cells (HCT116) and in vivo using relevant mouse models.

RESULTS

rNDV-TRAIL was found to exhibit better apoptotic efficacy than rNDV in CRC cells. Notably, rNDV-TRAIL had the stronger cancer cell-killing effect in TRAIL-resistant CRC cells. Western blot analyses showed that both rNDV and rNDV-TRAIL infections activate signaling proteins involved in the intrinsic and extrinsic apoptotic pathways. Notably, rNDV-TRAIL promotes concurrent intrinsic and extrinsic signal transduction in both HCT-116 and HT-29 cells.

CONCLUSIONS

Therefore, rNDV-TRAIL infection effectively enhances DR expression in DR-depressed HT-29 cells. Moreover, the TRAIL protein expressed by rNDV-TRAIL effectively interacts with DR, leading to enhanced apoptosis in TRAIL-resistant HT-29 cells. Therefore, rNDV-TRAIL has potential as a promising therapeutic approach for treating TRAIL-resistant cancers.

Therapeutic Targeting of Regulated Signaling Pathways of Non-Small Cell Lung Carcinoma

Non-small cell lung carcinoma (NSCLC) is the most common cancer globally. Phytochemicals and small molecule inhibitors significantly prevent varying types of cancers, including NSCLC. These therapeutic molecules serve as important sources for new drugs that interfere with cellular proliferation, apoptosis, metastasis, and angiogenesis by regulating signaling pathways. These molecules affect several cellular signaling cascades, including p53, NF-κB, STAT3, RAS, MAPK/ERK, Wnt, and AKT/PI3K, and are thus implicated in the therapeutic management of cancers. This review aims to describe the bioactive compounds and small-molecule inhibitors, their anticancer action, and targeting cellular signaling cascades in NSCLC. We highlighted the therapeutic potential of Epigallocatechin gallate (EGCG), Perifosine, ABT-737, Thymoquinine, Quercetin, Venetoclax, Gefitinib, and Genistein. These compounds are implicated in the therapeutic management of NSCLC. This review further offers deeper mechanistic insights into different signaling pathways that could be targeted for NSCLC therapy by phytochemicals and small-molecule inhibitors.

Potential medicinal plants to combat viral infections: A way forward to environmental biotechnology

The viral diseases encouraged scientific community to evaluate the natural antiviral bioactive components rather than protease inhibitors, harmful organic molecules or nucleic acid analogues. For this purpose, medicinal plants have been gaining tremendous importance in the field of attenuating the various kinds of infectious and non-infectious diseases. Most of the commonly used medicines contains the bioactive components/phytoconstituents that are generally extracted from medicinal plants. Moreover, the medicinal plants offer many advantages for the recovery applications of infectious disease especially in viral infections including HIV-1, HIV-2, Enterovirus, Japanese Encephalitis Virus, Hepatitis B virus, Herpes Virus, Respiratory syncytial virus, Chandipura virus and Influenza A/H1N1. Considering the lack of acceptable drug candidates and the growing antimicrobial resistance to existing drug molecules for many emerging viral diseases, medicinal plants may offer best platform to develop sustainable/efficient/economic alternatives against viral infections. In this regard, for exploring and analyzing large volume of scientific data, bibliometric analysis was done using VOS Viewer shedding light on the emerging areas in the field of medicinal plants and their antiviral activity. This review covers most of the plant species that have some novel bioactive compound like gnidicin, gniditrin, rutin, apigenin, quercetin, kaempferol, curcumin, tannin and oleuropin which showed high efficacy to inhibit the several disease causing virus and their mechanism of action in HIV, Covid-19, HBV and RSV were discussed. Moreover, it also delves the in-depth mechanism of medicinal with challenges and future prospective. Therefore, this work delves the key role of environment in the biological field.

Oncolytic virotherapy: basic principles, recent advances and future directions

Oncolytic viruses (OVs) have attracted growing awareness in the twenty-first century, as they are generally considered to have direct oncolysis and cancer immune effects. With the progress in genetic engineering technology, OVs have been adopted as versatile platforms for developing novel antitumor strategies, used alone or in combination with other therapies. Recent studies have yielded eye-catching results that delineate the promising clinical outcomes that OVs would bring about in the future. In this review, we summarized the basic principles of OVs in terms of their classifications, as well as the recent advances in OV-modification strategies based on their characteristics, biofunctions, and cancer hallmarks. Candidate OVs are expected to be designed as "qualified soldiers" first by improving target fidelity and safety, and then equipped with "cold weapons" for a proper cytocidal effect, "hot weapons" capable of activating cancer immunotherapy, or "auxiliary weapons" by harnessing tactics such as anti-angiogenesis, reversed metabolic reprogramming and decomposing extracellular matrix around tumors. Combinations with other cancer therapeutic agents have also been elaborated to show encouraging antitumor effects. Robust results from clinical trials using OV as a treatment congruously suggested its significance in future application directions and challenges in developing OVs as novel weapons for tactical decisions in cancer treatment.

Quercetin modulates signal transductions and targets non-coding RNAs against cancer development

In recent decades, various investigations have indicated that natural compounds have great potential in the prevention and treatment of different chronic disorders including different types of cancer. As a bioactive flavonoid, Quercetin (Qu) is a dietary ingredient enjoying high pharmacological values and health-promoting effects due to its antioxidant and anti-inflammatory characterization. Conclusive in vitro and in vivo evidence has revealed that Qu has great potential in cancer prevention and development. Qu exerts its anticancer influences by altering various cellular processes such as apoptosis, autophagy, angiogenesis, metastasis, cell cycle, and proliferation. In this way, Qu by targeting numerous signaling pathways as well as non-coding RNAs regulates several cellular mechanisms to suppress cancer occurrence and promotion. This review aimed to summarize the impact of Qu on the molecular pathways and non-coding RNAs in modulating various cancer-associated cellular mechanisms.

Apoptosis-related long non-coding RNA LINC5438 of Bombyx mori promotes the proliferation of BmNPV

Apoptosis, as an important part of the immune response, is one of the core events in the host-virus interaction. Studies have shown that long non-coding RNAs (lncRNAs) play important roles in the process of cell apoptosis and pathophysiology. To investigate the apoptosis-related lncRNAs involved in Bombyx mori nucleopolyhedrovirus (BmNPV) infecting silkworms, transcriptome sequencing was conducted based on silkworm cells infected with BmNPV before and after B. mori inhibitor of apoptosis (Bmiap) gene knockout. A total of 23 differentially expressed lncRNAs were identified as being associated with the mitochondrial apoptosis pathway. Moreover, we demonstrated that B. mori LINC5438 has the function of inhibiting apoptosis in silkworm cells. Overexpression of LINC5438 promoted the proliferation of BmNPV, while interference with LINC5438 inhibited its proliferation, indicating that LINC5438 plays an important role in BmNPV infection. Our results also showed that LINC5438 can regulate the expression of Bmiap, BmDronc, BmICE, and its predicted target gene BmAIF, suggesting that LINC5438 may function through the mitochondrial pathway. These findings provide important insights into the mechanisms of virus-host interaction and the applications of baculoviruses as biological insecticides.

Susceptibility and Permissivity of Zebrafish (Danio rerio) Larvae to Cypriniviruses

The zebrafish (Danio rerio) represents an increasingly important model organism in virology. We evaluated its utility in the study of economically important viruses from the genus Cyprinivirus (anguillid herpesvirus 1, cyprinid herpesvirus 2 and cyprinid herpesvirus 3 (CyHV-3)). This revealed that zebrafish larvae were not susceptible to these viruses after immersion in contaminated water, but that infections could be established using artificial infection models in vitro (zebrafish cell lines) and in vivo (microinjection of larvae). However, infections were transient, with rapid viral clearance associated with apoptosis-like death of infected cells. Transcriptomic analysis of CyHV-3-infected larvae revealed upregulation of interferon-stimulated genes, in particular those encoding nucleic acid sensors, mediators of programmed cell death and related genes. It was notable that uncharacterized non-coding RNA genes and retrotransposons were also among those most upregulated. CRISPR/Cas9 knockout of the zebrafish gene encoding protein kinase R (PKR) and a related gene encoding a protein kinase containing Z-DNA binding domains (PKZ) had no impact on CyHV-3 clearance in larvae. Our study strongly supports the importance of innate immunity-virus interactions in the adaptation of cypriniviruses to their natural hosts. It also highlights the potential of the CyHV-3-zebrafish model, versus the CyHV-3-carp model, for study of these interactions.

The Enigma of Lymphocyte Apoptosis in the Response to Influenza Virus Infection

In the pathogenesis of influenza virus infection, lymphocyte apoptosis as a part of the infection and/or the immune response to the virus can be somewhat puzzling. The percentage of human T lymphocytes within the peripheral blood mononuclear cell population that becomes apoptotic greatly exceeds the percentage that are infected after exposure to the virus, consistent with substantial apoptosis of bystander T lymphocytes. Studies reveal an important role of viral neuraminidase expression by co-cultured monocyte/macrophages in induction of apoptosis, including that of uninfected bystander lymphocytes. Despite these observations, it is a reasonable perspective to recognize that the development of lymphocyte apoptosis during the response to infection does not preclude a successful immune response and recovery of the infected host in the great majority of cases. Further investigation is clearly warranted to understand its role in the pathogenesis of influenza virus infection for human subjects.

Hepatitis B Virus (HBV) Upregulates TRAIL-R3 Expression in Hepatocytes Resulting in Escape From Both Cell Apoptosis and Suppression of HBV Replication by TRAIL

BACKGROUND

Hepatitis B virus (HBV) evades host immunity by regulating intracellular signals. To clarify this immune tolerance mechanism, we performed gene expression analysis using HBV-infected humanized mouse livers.

METHODS

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 3 (TRAIL-R3) was significantly upregulated in livers of HBV-infected human hepatocyte transplanted mice by cDNA microarray and next-generation sequencing. We analyzed the significance of TRAIL-R3 upregulation in HBV infection using human hepatocyte transplanted mice and HepG2 cell lines.

RESULTS

TRAIL-R3 induction by HBV infection was verified by in vitro and in vivo HBV replication models, and induction was inhibited by antiviral nucleot(s)ide analogue treatment. TRAIL-R3 transcription was regulated by the TRAIL-R3 promoter at -969 to -479 nucleotides upstream from the transcription start site, and by hepatitis B x (HBx) via activation of nuclear factor-κB (NF-κB) signal. TRAIL not only induced cell apoptosis but also inhibited HBV replication. TRAIL-R3 upregulation could inhibit both TRAIL-dependent apoptosis in HBV-infected hepatocytes and TRAIL-mediated suppression of HBV replication.

CONCLUSIONS

These results suggest a mechanism by which HBV persists by escaping host immunity through upregulation of TRAIL-R3. Development of novel drugs to inhibit this escape system might lead to complete HBV elimination from human hepatocytes.

Nucleolin mediates SARS-CoV-2 replication and viral-induced apoptosis of host cells

Host-oriented antiviral therapeutics are promising treatment options to combat COVID-19 and its emerging variants. However, relatively little is known about the cellular proteins hijacked by SARS-CoV-2 for its replication. Here we show that SARS-CoV-2 induces expression and cytoplasmic translocation of the nucleolar protein, nucleolin (NCL). NCL interacts with SARS-CoV-2 viral proteins and co-localizes with N-protein in the nucleolus and in stress granules. Knockdown of NCL decreases the stress granule component G3BP1, viral replication and improved survival of infected host cells. NCL mediates viral-induced apoptosis and stress response via p53. SARS-CoV-2 increases NCL expression and nucleolar size and number in lungs of infected hamsters. Inhibition of NCL with the aptamer AS-1411 decreases viral replication and apoptosis of infected cells. These results suggest nucleolin as a suitable target for anti-COVID therapies.

White Spot Syndrome Virus (WSSV) Inhibits Hippo Signaling and Activates Yki To Promote Its Infection in Penaeus vannamei

White spot syndrome virus (WSSV) is a serious threat to shrimp aquaculture, especially Pacific white shrimp, Penaeus vannamei, the most farmed shrimp in the world. Activation of the Hippo-Yki signaling pathway, characterized by the intracellular Hippo-Wts kinase cascade reactions and the phosphorylation and cytoplasmic retention of Yki, is widely involved in various life activities. The current work established the fundamental structure and signal transduction profile of the Hippo-Yki pathway in P. vannamei and further investigated its role in viral infection. We demonstrated that WSSV promoted the dephosphorylation and nuclear translocation of Yki, suggesting that Hippo signaling is impaired and Yki is activated after WSSV infection in shrimp. In vivo, Yki gene silencing suppressed WSSV infection, while Hippo and Wts silencing promoted it, indicating a positive role of Hippo signaling in antiviral response. Further analyses showed that Yki suppressed Dorsal pathway activation and inhibited hemocyte apoptosis in WSSV-infected shrimp, while Hippo and Wts showed opposite effects, which contributed to the role of Hippo signaling in WSSV infection. Therefore, the current study suggests that WSSV annexes Yki to favor its infection in shrimp by inhibiting Hippo signaling. IMPORTANCE White spot syndrome virus (WSSV) is one of the most harmful viral pathogens to shrimp. The pathological mechanism of WSSV infection remains unclear to date. The Hippo-Yki signaling pathway is important for various biological processes and is extensively involved in mammalian immunity, but little is known about its role in infectious diseases in invertebrates. Based on revealing the fundamental structure of the shrimp Hippo pathway, this study investigated its implication in the pathogenesis of WSSV disease. We demonstrated that WSSV enhanced Yki activation by inhibiting Hippo signaling in shrimp. The activated Yki promoted WSSV infection by inhibiting hemocyte apoptosis and suppressing the activation of Dorsal, an NF-κB family member in shrimp that is critical for regulating antiviral response. Therefore, this study suggests that WSSV can hijack the Hippo-Yki signaling pathway to favor its infection in shrimp.

Enhancer Clusters Drive Type I Interferon-Induced TRAIL Overexpression in Cancer, and Its Intracellular Protein Accumulation Fails to Induce Apoptosis

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a cytokine produced and secreted by immune cells in response to an infection, often in response to interferon (IFN) stimulation. In cancer, it has also been shown that IFN stimulates the production of TRAIL, and it has been proposed that this TRAIL can induce apoptosis in an autocrine or paracrine manner in different cancer cells. Yet, the mechanism mediating TRAIL upregulation and the implications of TRAIL as an apoptotic molecule in cancer cells are still poorly understood. We show here that in certain cancer cells, TRAIL is upregulated by enhancer clusters, potent genomic regulatory regions containing densely packed enhancers that have combinatorial and additive activity and that are usually found to be associated with cancer-promoting genes. Moreover, we found that TRAIL upregulation by IFNα is mediated by these enhancer clusters in breast and lung cancer cells. Surprisingly, IFNα stimulation leads to the intracellular accumulation of TRAIL protein in these cancer cells. Consequently, this TRAIL is not capable of inducing apoptosis. Our study provides novel insights into the mechanism behind the interferon-mediated upregulation of TRAIL and its protein accumulation in cancer cells. Further investigation is required to understand the role of intracellular TRAIL or depict the mechanisms mediating its apoptosis impairment in cancer cells.

A literature review of microRNA and gene signaling pathways involved in the apoptosis pathway of lung cancer

BACKGROUND

Lung cancer is one of the leading causes of death in the world and the deadliest of all cancers. Apoptosis is a key pathway in regulating the cell growth rate, proliferation, and occurrence of lung cancer. This process is controlled by many molecules, such as microRNAs and their target genes. Therefore, finding new medical approaches such as exploring diagnostic and prognostic biomarkers involved in apoptosis is needed for this disease. In the present study, we aimed to identify key microRNAs and their target genes that could be used in the prognosis and diagnosis of lung cancer.

METHODS

Signaling pathways, genes, and microRNAs involved in the apoptotic pathway were identified by bioinformatics analysis and recent clinical studies. Bioinformatics analysis was performed on databases including NCBI, TargetScan, UALCAN, UCSC, KEGG, miRPathDB, and Enrichr, and clinical studies were extracted from PubMed, web of science, and SCOPUS databases.

RESULTS

NF-κB, PI3K/AKT, and MAPK pathways play critical roles in the regulation of apoptosis. MiR-146b, 146a, 21, 23a, 135a, 30a, 202, and 181 were identified as the involved microRNAs in the apoptosis signaling pathway, and IRAK1, TRAF6, Bcl-2, PTEN, Akt, PIK3, KRAS, and MAPK1 were classified as the target genes of the mentioned microRNAs respectively. The essential roles of these signaling pathways and miRNAs/target genes were approved through both databases and clinical studies. Moreover, surviving, living, BRUCE, and XIAP was the main inhibitor of apoptosis which act by regulating the apoptosis-involved genes and miRNAs.

CONCLUSION

Identifying the abnormal expression and regulation of miRNAs and signaling pathways in apoptosis of lung cancer can represent a novel class of biomarkers that can facilitate the early diagnosis, personalized treatment, and prediction of drug response for lung cancer patients. Therefore, studying the mechanisms of apoptosis including signaling pathways, miRNAs/target genes, and the inhibitors of apoptosis are advantageous for finding the most practical approach and reducing the pathological demonstrations of lung cancer.

Transcriptome analysis of PK-15 cells expressing CSFV NS4A

BACKGROUND

Classical swine fever (CSF) is a severe disease of pigs that results in huge economic losses worldwide and is caused by classical swine fever virus (CSFV). CSFV nonstructural protein 4 A (NS4A) plays a crucial role in infectious CSFV particle formation. However, the function of NS4A during CSFV infection is not well understood.  RESULTS: In this study, we used RNA-seq to investigate the functional role of CSFV NS4A in PK-15 cells. A total of 3893 differentially expressed genes (DEGs) were identified in PK-15 cells expressing NS4A compared to cells expressing the empty vector (NC). Twelve DEGs were selected and further verified by RT‒qPCR. GO and KEGG enrichment analyses revealed that these DEGs were associated with multiple biological functions, including cell adhesion, apoptosis, host defence response, the inflammatory response, the immune response, and autophagy. Interestingly, some genes associated with host immune defence and inflammatory response were downregulated, and some genes associated with host apoptosis and autophagy were upregulated.

CONCLUSION

CSFV NS4A inhibits the innate immune response, and suppresses the expression of important genes associated with defence response to viruses and inflammatory response, and regulates cell adhesion, apoptosis and autophagy.

MicroRNAs as immune regulators and biomarkers in tuberculosis

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis (Mtb), is one of the most lethal infectious disease worldwide, and it greatly affects human health. Some diagnostic and therapeutic methods are available to effectively prevent and treat TB; however, only a few systematic studies have described the roles of microRNAs (miRNAs) in TB. Combining multiple clinical datasets and previous studies on Mtb and miRNAs, we state that pathogens can exploit interactions between miRNAs and other biomolecules to avoid host mechanisms of immune-mediated clearance and survive in host cells for a long time. During the interaction between Mtb and host cells, miRNA expression levels are altered, resulting in the changes in the miRNA-mediated regulation of host cell metabolism, inflammatory responses, apoptosis, and autophagy. In addition, differential miRNA expression can be used to distinguish healthy individuals, patients with TB, and patients with latent TB. This review summarizes the roles of miRNAs in immune regulation and their application as biomarkers in TB. These findings could provide new opportunities for the diagnosis and treatment of TB.

Redox Status Is the Mainstay of SARS-CoV-2 and Host for Producing Therapeutic Opportunities

Over hundreds of years, humans have faced multiple pandemics and have overcome many of them with scientific advancements. However, the recent coronavirus disease (COVID-19) has challenged the physical, mental, and socioeconomic aspects of human life, which has introduced a general sense of uncertainty among everyone. Although several risk profiles, such as the severity of the disease, infection rate, and treatment strategy, have been investigated, new variants from different parts of the world put humans at risk and require multiple strategies simultaneously to control the spread. Understanding the entire system with respect to the commonly involved or essential mechanisms may be an effective strategy for successful treatment, particularly for COVID-19. Any treatment for COVID-19 may alter the redox profile, which can be an effective complementary method for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry and further replication. Indeed, redox profiles are one of the main barriers that suddenly shift the immune response in favor of COVID-19. Fortunately, several redox components exhibit antiviral and anti-inflammatory activities. However, access to these components as support elements against COVID-19 is limited. Therefore, understanding redox-derived species and their nodes as a common interactome in the system will facilitate the treatment of COVID-19. This review discusses the redox-based perspectives of the entire system during COVID-19 infection, including how redox-based molecules impact the accessibility of SARS-CoV-2 to the host and further replication. Additionally, to demonstrate its feasibility as a viable approach, we discuss the current challenges in redox-based treatment options for COVID-19.

Molecular cloning, functional characterization of duck TRADD and its effect on infection with duck Tembusu virus

Tumor necrosis factor receptor 1 (TNFR1) associated death domain protein (TRADD) is a pivotal adaptor in TNF signaling pathway and plays an important role in apoptosis and immune regulation. The function of TRADD has been investigated extensively in mammals, however, the role of TRADD in ducks remains obscure. To reveal the function of duck TRADD (duTRADD) in the apoptosis and innate immune response, the TRADD homologue of mallard (Anas platyrhynchos) has been cloned and the function of duTRADD is investigated in this study. We conducted sequence analysis of the duTRADD, the open reading frame (ORF) region of duTRADD gene was 1065 bp, encoding 354 amino acids (aa), which shares similar functional domain to its mammalian counterpart. Tissue distribution profile of duTRADD in 7-day-old ducklings showed that the expression level of the gene was the highest in heart, followed by liver and brain. Accordingly, duck Tembusu virus (DTMUV) has been shown to decrease duTRADD expression, while overexpression of duTRADD inhibited DTMUV replication in a dose-dependent manner. Furthermore, duTRADD activated the transcriptional activity of caspase-3/8/9, the flow cytometry showed that duTRADD significantly induced apoptosis. However, duTRADD showed hardly any effect on the transcriptional activity of IFN-α/β and its downstream interferon-stimulated genes (ISGs). The current data support the conclusion that duTRADD is a novel pro-apoptotic protein with a critical role in defense against DTMUV invasion. These results lay the theoretical foundation for the development of new anti-DTMUV strategies.

Mucosal Immunity After Novel COVID-19 Infection – Virus-Induced Immunosuppression: Preliminary Study

In recovered COVID-19 patients, the state of mucosal immunity remains understudied. Cytological, functional, and metabolic characteristics of neutrophils and the interleukin status will help to correctly assess the need for immunorehabilitation measures. The study objective is to assess the state of mucosal immunity after COVID-19. A comprehensive study of mucosal immunity included the assessment of nasal mucosal neutrophils with the monitoring of destructive and apoptotic changes as well as examination of the functional and metabolic activity of neutrophils entering the nasal secretions. Phagocytic activity was assessed using microbial suspension of Staphylococcus aureus, as well as intracellular oxygen-dependent biocidity, the functions of capturing, absorbing, and killing pathogens. Study of the secretory component included assessment of interleukin levels (TNF-α, IL-10, IFN-γ) and the content of sCD95 (sAPO-1/FAS), membrane marker of apoptosis, in the nasal secretions. Cell wall neutrophils in recovered COVID-19 patients show enhanced destructive and apoptotic processes within the cells. Functional disorders due to inhibited phagocytosis of autoflora are recorded. Functionally defective cells are brought into the nasal secretions; they demonstrate severely inhibited oxygen-dependent biocidity, rapid depletion of reserves, incomplete phagocytosis, and limited ability to capture pathogens, which can contribute to the growth of various pathogenic viruses and bacteria. In the nasal secretions, the concentration of sCD95 (sAPO-1/FAS), the membrane marker of apoptosis, is increased. Elevated level of pro- and anti-inflammatory cytokines (TNF-α, IL-10) downregulates IFN-γ, thus directly contributing to the formation of functionally defective neutrophils. Compensatory increase in the IL-10 anti-inflammatory cytokine under the influence of SARS-CoV-2 virus proteins downregulates IFN-γ and is a cofactor of depression of intracellular biocidity of neutrophils. An increased level of the TNF-α pro-inflammatory cytokine increases apoptotic and destructive changes in neutrophils entering the nasal secretion. Virus-induced, functional, and metabolic impairment of neutrophils of the mucosal immunity system develop in recovered COVID-19 patients, thus providing a scientific rationale for immunomodulatory therapy.

Phenotypic and Transcriptional Changes of Pulmonary Immune Responses in Dogs Following Canine Distemper Virus Infection

Canine distemper virus (CDV), a morbillivirus within the family Paramyxoviridae, is a highly contagious infectious agent causing a multisystemic, devastating disease in a broad range of host species, characterized by severe immunosuppression, encephalitis and pneumonia. The present study aimed at investigating pulmonary immune responses of CDV-infected dogs in situ using immunohistochemistry and whole transcriptome analyses by bulk RNA sequencing. Spatiotemporal analysis of phenotypic changes revealed pulmonary immune responses primarily driven by MHC-II⁺, Iba-1⁺ and CD204⁺ innate immune cells during acute and subacute infection phases, which paralleled pathologic lesion development and coincided with high viral loads in CDV-infected lungs. CD20⁺ B cell numbers initially declined, followed by lymphoid repopulation in the advanced disease phase. Transcriptome analysis demonstrated an increased expression of transcripts related to innate immunity, antiviral defense mechanisms, type I interferon responses and regulation of cell death in the lung of CDV-infected dogs. Molecular analyses also revealed disturbed cytokine responses with a pro-inflammatory M1 macrophage polarization and impaired mucociliary defense in CDV-infected lungs. The exploratory study provides detailed data on CDV-related pulmonary immune responses, expanding the list of immunologic parameters potentially leading to viral elimination and virus-induced pulmonary immunopathology in canine distemper.

Advances in cell death mechanisms involved in viral myocarditis

Viral myocarditis is an acute inflammatory disease of the myocardium. Although many etiopathogenic factors exist, coxsackievirus B3 is a the leading cause of viral myocarditis. Abnormal cardiomyocyte death is the underlying problem for most cardiovascular diseases and fatalities. Various types of cell death occur and are regulated to varying degrees. In this review, we discuss the different cell death mechanisms in viral myocarditis and the potential interactions between them. We also explore the role and mechanism of cardiomyocyte death with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Exploring the mechanisms may help in the early identification and the development of effective treatments, thus improving the quality of life of patients with viral myocarditis. We believe that the inhibition of cardiomyocyte death has immense therapeutic potential in increasing the longevity and health of the heart.

Non-pathogenic grass carp reovirus infection leads to both apoptosis and autophagy in a grass carp cell line

A novel GCRV strain isolated from healthy grass carp was named as grass carp reovirus - HH196 (GCRV-HH196), and its infection mechanism remains unclear. In this study, the grass carp ovary cell line (GCO cells) was used to investigate the cell death involved in GCRV-HH196 infection. The results showed that DNA damage, cells volume reduction and cytoplasm shrinkage happened during GCRV-HH196 infection. The mRNA expression levels of pro-apoptotic genes were up-regulated during infection. Two initiators of apoptosis, caspase 8 and caspase 9, and the executioner of apoptosis, caspase 3, were all significantly activated in GCRV-HH196-infected cells. Flow cytometry analysis showed that the number of apoptotic cells in infected cells was significantly higher than that in control cells as the infection progress. Meanwhile, autophagy was also involved in the regulation of GCRV - HH196 infection. We observed that LC3 puncta existed in cytoplasm in GCRV-HH196-infected cells. Furthermore, the protein level of LC3-Ⅱ and Beclin-1 increased, while that of p-Akt decreased in GCRV-HH196-infected cells. These results demonstrated that GCRV-HH196 may regulate apoptosis and autophagy for the virus proliferation and spread, which set a foundation for further research on the interaction between GCRV-HH196 and host.

Viral-mediated activation and inhibition of programmed cell death

Viruses are ubiquitous intracellular genetic parasites that heavily rely on the infected cell to complete their replication life cycle. This dependency on the host machinery forces viruses to modulate a variety of cellular processes including cell survival and cell death. Viruses are known to activate and block almost all types of programmed cell death (PCD) known so far. Modulating PCD in infected hosts has a variety of direct and indirect effects on viral pathogenesis and antiviral immunity. The mechanisms leading to apoptosis following virus infection is widely studied, but several modalities of PCD, including necroptosis, pyroptosis, ferroptosis, and paraptosis, are relatively understudied. In this review, we cover the mechanisms by which viruses activate and inhibit PCDs and suggest perspectives on how these affect viral pathogenesis and immunity.

Comprehensive profiling and characterization of cellular microRNAs in response to coxsackievirus A10 infection in bronchial epithelial cells

Coxsackievirus A10 (CV-A10), the causative agent of hand, foot, and mouth disease (HFMD), caused a series of outbreaks in recent years and often leads to neurological impairment, but a clear understanding of the disease pathogenesis and host response remains elusive. Cellular microRNAs (miRNAs), a large family of non-coding RNA molecules, have been reported to be key regulators in viral pathogenesis and virus-host interactions. However, the role of host cellular miRNAs defensing against CV-A10 infection is still obscure. To address this issue, we systematically analyzed miRNA expression profiles in CV-A10-infected 16HBE cells by high-throughput sequencing methods in this study. It allowed us to successfully identify 312 and 278 miRNAs with differential expression at 12 h and 24 h post-CV-A10 infection, respectively. Among these, 4 miRNAs and their target genes were analyzed by RT-qPCR, which confirmed the sequencing data. Gene target prediction and enrichment analysis revealed that the predicted targets of these miRNAs were significantly enriched in numerous cellular processes, especially in regulation of basic physical process, host immune response and neurological impairment. And the integrated network was built to further indicate the regulatory roles of miRNAs in host-CV-A10 interactions. Consequently, our findings could provide a beneficial basis for further studies on the regulatory roles of miRNAs relevant to the host immune responses and neuropathogenesis caused by CV-A10 infection.

Largemouth Bass Virus Infection Induced Non-Apoptotic Cell Death in MsF Cells

Largemouth bass virus (LMBV), belonging to the genus Ranavirus, causes high mortality and heavy economic losses in largemouth bass aquaculture. In the present study, a novel cell line, designated as MsF, was established from the fin of largemouth bass (Micropterus salmoides), and applied to investigate the characteristics of cell death induced by LMBV. MsF cells showed susceptibility to LMBV, evidenced by the occurrence of a cytopathic effect (CPE), increased viral gene transcription, protein synthesis, and viral titers. In LMBV-infected MsF cells, two or more virus assembly sites were observed around the nucleus. Notably, no apoptotic bodies occurred in LMBV-infected MsF cells after nucleus staining, suggesting that cell death induced by LMBV in host cells was distinct from apoptosis. Consistently, DNA fragmentation was not detected in LMBV-infected MsF cells. Furthermore, only caspase-8 and caspase-3 were significantly activated in LMBV-infected MsF cells, suggesting that caspases were involved in non-apoptotic cell death induced by LMBV in host cells. In addition, the disruption of the mitochondrial membrane potential (ΔΨm) and reactive oxygen species (ROS) generation were detected in both LMBV-infected MsF cells and fathead minnow (FHM) cells. Combined with our previous study, we propose that cell death induced by LMBV infection was cell type dependent. Although LMBV-infected MsF cells showed the characteristics of non-apoptotic cell death, the signal pathways might crosstalk and interconnect between apoptosis and other PCD during LMBV infection. Together, our results not only established the in vitro LMBV infection model for the study of the interaction between LMBV and host cells but also shed new insights into the mechanisms of ranavirus pathogenesis.

SARS-CoV-2 Infection of Microglia Elicits Proinflammatory Activation and Apoptotic Cell Death

Accumulating evidence suggests that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes various neurological symptoms in patients with coronavirus disease 2019 (COVID-19). The most dominant immune cells in the brain are microglia. Yet, the relationship between neurological manifestations, neuroinflammation, and host immune response of microglia to SARS-CoV-2 has not been well characterized. Here, we reported that SARS-CoV-2 can directly infect human microglia, eliciting M1-like proinflammatory responses, followed by cytopathic effects. Specifically, SARS-CoV-2 infected human microglial clone 3 (HMC3), leading to inflammatory activation and cell death. RNA sequencing (RNA-seq) analysis also revealed that endoplasmic reticulum (ER) stress and immune responses were induced in the early, and apoptotic processes in the late phases of viral infection. SARS-CoV-2-infected HMC3 showed the M1 phenotype and produced proinflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor α (TNF-α), but not the anti-inflammatory cytokine IL-10. After this proinflammatory activation, SARS-CoV-2 infection promoted both intrinsic and extrinsic death receptor-mediated apoptosis in HMC3. Using K18-hACE2 transgenic mice, murine microglia were also infected by intranasal inoculation of SARS-CoV-2. This infection induced the acute production of proinflammatory microglial IL-6 and TNF-α and provoked a chronic loss of microglia. Our findings suggest that microglia are potential mediators of SARS-CoV-2-induced neurological problems and, consequently, can be targets of therapeutic strategies against neurological diseases in patients with COVID-19. IMPORTANCE Recent studies reported neurological and cognitive sequelae in patients with COVID-19 months after the viral infection with several symptoms, including ageusia, anosmia, asthenia, headache, and brain fog. Our conclusions raise awareness of COVID-19-related microglia-mediated neurological disorders to develop treatment strategies for the affected patients. We also indicated that HMC3 was a novel human cell line susceptible to SARS-CoV-2 infection that exhibited cytopathic effects, which could be further used to investigate cellular and molecular mechanisms of neurological manifestations of patients with COVID-19.

The Apoptotic and Antiproliferative Effects of Capsaicin in the Developmental Stages of Oral Squamous Cell Carcinoma Induced in Hamsters

Background and aim

Several epidemiological and experimental studies have approve that the vegetarian diet has an anticancer effect. Capsaicin is the active botanical ingredient found in red chili peppers. While the data strongly argue for the significant anticancer benefits of capsaicin, nevertheless, much information is required to shed light on the anticancer molecular mechanisms to improve knowledge and suggest potential therapeutic mechanisms for the use of capsaicin against cancer. This study aimed to investigate the effect of capsaicin on the rate of cell division and apoptosis in the development of oral squamous cell carcinoma induced in the buccal pouch of hamsters.

Materials and methods

The sample consisted of two groups; the first group consisted of 20 hamsters with the application of carcinogenic 7,12-dimethylbenz(a)anthracene (DMBA) in the buccal pouch (the control group) and the second group (the study group) also consisted of 20 hamsters with the application of DMBA in alternatively with capsaicin. Tissue biopsies were taken from experimental animals after sacrificing. The samples were immunostained for the detection of Ki-67 and Bcl-2 proteins.

Results

Immunohistochemical staining by monoclonal antibody to Ki-67 and Bcl-2 in the study group showed lower expression at all stages of oral cancer development compared with their expression in the control group. After performing the one-way (ANOVA) test, we found statistically significant differences by comparing the expression degree of Ki-67 and Bcl-2 proteins in both study groups, where the p-value was less than 0.05.

Conclusion

We conclude from the data of our study that capsaicin has an anti-cancer role in oral squamous cell carcinoma if applied in the digestive tract of experimental animals by inhibiting the proliferation of cancer cells and activating apoptosis in them.

The Endless Wars: Severe Fever With Thrombocytopenia Syndrome Virus, Host Immune and Genetic Factors

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging arboviral infectious disease with a high rate of lethality in susceptible humans and caused by severe fever with thrombocytopenia syndrome bunyavirus (SFTSV). Currently, neither vaccine nor specific antiviral drugs are available. In recent years, given the fact that both the number of SFTS cases and epidemic regions are increasing year by year, SFTS has become a public health problem. SFTSV can be internalized into host cells through the interaction between SFTSV glycoproteins and cell receptors and can activate the host immune system to trigger antiviral immune response. However, SFTSV has evolved multiple strategies to manipulate host factors to create an optimal environment for itself. Not to be discounted, host genetic factors may be operative also in the never-ending winning or losing wars. Therefore, the identifications of SFTSV, host immune and genetic factors, and their interactions are critical for understanding the pathogenic mechanisms of SFTSV infection. This review summarizes the updated pathogenesis of SFTS with regard to virus, host immune response, and host genetic factors to provide some novel perspectives of the prevention, treatment, as well as drug and vaccine developments.

Transcriptome profiling in swine macrophages infected with African swine fever virus at single-cell resolution

African swine fever virus (ASFV) causes a severe and highly contagious disease in pigs and wild boars, but no commercial vaccines or antivirals are available currently. Understanding the mutual antagonism between virus and host factors during ASFV infection may facilitate the development of new vaccines and antivirals. Our work profiled transcriptomes of swine macrophages infected with ASFV through single-cell RNA-sequencing technology. Identified dynamic transcriptome events of viral genes provide molecular characteristics of ASFV during infection. Moreover, virus–host interactions imply the regulation pathway of viral replication in host cells, which may guide research on antiviral strategies and dissection of ASFV pathogenesis.

African swine fever virus (ASFV) is the causative agent of African swine fever, a highly contagious and usually fatal disease in pigs. The pathogenesis of ASFV infection has not been clearly elucidated. Here, we used single-cell RNA-sequencing technology to survey the transcriptomic landscape of ASFV-infected primary porcine alveolar macrophages. The temporal dynamic analysis of viral genes revealed increased expression of viral transmembrane genes. Molecular characteristics in the ASFV-exposed cells exhibited the activation of antiviral signaling pathways with increased expression levels of interferon-stimulated genes and inflammatory- and cytokine-related genes. By comparing infected cells with unexposed cells, we showed that the unfolded protein response (UPR) pathway was activated in low viral load cells, while the expression level of UPR-related genes in high viral load cells was less than that in unexposed cells. Cells infected with various viral loads showed signature transcriptomic changes at the median progression of infection. Within the infected cells, differential expression analysis and coregulated virus–host analysis both demonstrated that ASFV promoted metabolic pathways but inhibited interferon and UPR signaling, implying the regulation pathway of viral replication in host cells. Furthermore, our results revealed that the cell apoptosis pathway was activated upon ASFV infection. Mechanistically, the production of tumor necrosis factor alpha (TNF-α) induced by ASFV infection is necessary for cell apoptosis, highlighting the importance of TNF-α in ASFV pathogenesis. Collectively, the data provide insights into the comprehensive host responses and complex virus–host interactions during ASFV infection, which may instruct future research on antiviral strategies.