Palmitoylation of NLRP3 Modulates Inflammasome Activation and Inflammatory Bowel Disease Development.

Aberrant activity of NLRP3 has been shown associations with severe diseases. Palmitoylation is a kind of protein post-translational modification, which has been shown to regulate cancer development and the innate immune system. Here, we showed that NLRP3 is palmitoylated at Cys419 and that palmitoyltransferase ZDHHC17 is the predominant enzyme that mediates NLRP3 palmitoylation and promotes NLRP3 activation by interacting with NLRP3 and facilitating NIMA-related kinase 7 (NEK7)-NLRP3 interactions. Blockade of NLRP3 palmitoylation by a palmitoylation inhibitor, 2-bromopalmitate, effectively inhibited NLRP3 activation in vitro. Also, in a dextran sulfate sodium-induced colitis model in mice, 2-bromopalmitate application could attenuate weight loss, improve the survival rate, and rescue pathological changes in the colon of mice. Overall, our study reveals that palmitoylation of NLPR3 modulates inflammasome activation and inflammatory bowel disease development. We propose that drugs targeting NLRP3 palmitoylation could be promising candidates in the treatment of NLRP3-mediated inflammatory diseases.

Discovery of aphid-transmitted Rice tiller inhibition virus from native plants through metagenomic sequencing.

A major threat to rice production is the disease epidemics caused by insect-borne viruses that emerge and re-emerge with undefined origins. It is well known that some human viruses have zoonotic origins from wild animals. However, it remains unknown whether native plants host uncharacterized endemic viruses with spillover potential to rice (Oryza sativa) as emerging pathogens. Here, we discovered rice tiller inhibition virus (RTIV), a novel RNA virus species, from colonies of Asian wild rice (O. rufipogon) in a genetic reserve by metagenomic sequencing. We identified the specific aphid vector that is able to transmit RTIV and found that RTIV would cause low-tillering disease in rice cultivar after transmission. We further demonstrated that an infectious molecular clone of RTIV initiated systemic infection and causes low-tillering disease in an elite rice variety after Agrobacterium-mediated inoculation or stable plant transformation, and RTIV can also be transmitted from transgenic rice plant through its aphid vector to cause disease. Finally, global transcriptome analysis indicated that RTIV may disturb defense and tillering pathway to cause low tillering disease in rice cultivar. Thus, our results show that new rice viral pathogens can emerge from native habitats, and RTIV, a rare aphid-transmitted rice viral pathogen from native wild rice, can threaten the production of rice cultivar after spillover.

Insights into the complexity and functionality of plant virus protein phosphorylation.

Phosphorylation, the most extensive and pleiotropic form of protein post-translation modification, is central to cellular signal transduction. Throughout the extensive co-evolution of plant hosts and viruses, modifications to phosphorylation have served multiple purposes. Such modifications highlight the evolutionary trajectories of viruses and their hosts, with pivotal roles in regulation and refinement of host-virus interactions. In plant hosts, protein phosphorylation orchestrates immune responses, enhancing the activities of defense-related proteins such as kinases and transcription factors, thereby strengthening pathogen resistance in plants. Moreover, phosphorylation influences the interactions between host and viral proteins, altering viral spread and replication within host plants. In the context of plant viruses, protein phosphorylation controls key aspects of the infection cycle, including viral protein functionality and the interplay between viruses and host plant cells, leading to effects on viral accumulation and dissemination within plant tissues. Explorations of the nuances of protein phosphorylation in plant hosts and their interactions with viruses are particularly important. This review provides a systematic summary of the biological roles of the proteins of plant viruses carrying diverse genomes in regulating infection and host responses through changes in the phosphorylation status.

A conserved methyltransferase active site residue of Zika virus NS5 is required for the restriction of STING activation and interferon expression.

Zika virus (ZIKV) is a re-emerging RNA virus and causes major public health events due to its link to severe neurological complications in foetuses and neonates. The cGAS-STING signalling pathway regulates innate immunity and plays an important role in the invasion of DNA and RNA viruses. This study reveals a distinct mechanism by which ZIKV restricts the cGAS-STING signalling to repress IFN-ß expression. ZIKV attenuates IFN-ß expression induced by DNA viruses (herpes simplex virus type 1, HSV-1) or two double-stranded DNAs (dsDNA90 and HSV120) in mouse embryonic fibroblasts (MEFs). Notably, ZIKV NS5, the viral RNA-dependent RNA polymerase, was responsible for the repression of IFN-ß. NS5 interacts with STING in the cytoplasm, suppresses IRF3 phosphorylation and nucleus localization and promotes the cleavage of STING K48-linked polyubiquitination. Furthermore, the NS5 methyltransferase (MTase) domain interacts with STING to restrict STING-induced IFN-ß expression. Interestingly, point mutation analyses of conserved methyltransferase active site residue D146 indicate that it is critical for repressing IFN-ß expression induced by STING stimulation in cGAS-STING signalling.

The G allele of SNP rs3922 reduces the binding affinity between IGF2BP3 and CXCR5 correlating with a lower antibody production.

Effective vaccines that function through humoral immunity seek to produce high-affinity antibodies. Our previous research identified the single-nucleotide polymorphism rs3922G in the 3'UTR of CXCR5 as being associated with nonresponsiveness to the hepatitis B vaccine. The differential expression of CXCR5 between the dark zone (DZ) and light zone (LZ) is critical for organizing the functional structure of the germinal center (GC). In this study, we report that the RNA-binding protein IGF2BP3 can bind to CXCR5 mRNA containing the rs3922 variant to promote its degradation via the nonsense-mediated mRNA decay pathway. Deficiency of IGF2BP3 leads to increased CXCR5 expression, which results in the disappearance of CXCR5 differential expression between DZ and LZ, disorganized GCs, aberrant somatic hypermutations, and reduced production of high-affinity antibodies. Furthermore, the affinity of IGF2BP3 for the rs3922G-containing sequence is lower than that for the rs3922A counterpart, which may explain the nonresponsiveness to the hepatitis B vaccination. Together, our findings suggest that IGF2BP3 plays a crucial role in the production of high-affinity antibodies in the GC by binding to the rs3922-containing sequence to regulate CXCR5 expression.

Plasmodesmata-associated Flotillin positively regulates broad-spectrum virus cell-to-cell trafficking.

Viral diseases seriously threaten rice production. Plasmodesmata (PD)-associated proteins are deemed to play a key role in viral infection in host plants. However, few PD-associated proteins have been discovered in rice to afford viral infection. Here, inspired by the infection mechanism in insect vectors, we identified a member of the Flotillin family taking part in the cell-to-cell transport of rice stripe virus (RSV) in rice. Flotillin1 interacted with RSV nucleocapsid protein (NP) and was localized on PD. In flotillin1 knockout mutant rice, which displayed normal growth, RSV intercellular movement was retarded, leading to significantly decreased disease incidence. The PD pore sizes of the mutant rice were smaller than those of the wild type due to more callose deposits, which was closely related to the upregulation of two callose synthase genes. RSV infection stimulated flotillin1 expression and enlarged the PD aperture via RSV NP. In addition, flotillin1 knockout decreased disease incidences of southern rice black-streaked dwarf virus (SRBSDV) and rice dwarf virus (RDV) in rice. Overall, our study reveals a new PD-associated protein facilitating virus cell-to-cell trafficking and presents the potential of flotillin1 as a target to produce broad-spectrum antiviral rice resources in the future.

Generation of Human Embryonic Stem Cell-Derived Lung Organoids for Modeling Infection and Replication Differences between Human Adenovirus Types 3 and 55 and Evaluating Potential Antiviral Drugs.

Human adenoviruses type 3 (HAdV-3) and type 55 (HAdV-55) are frequently encountered, highly contagious respiratory pathogens with high morbidity rate. In contrast to HAdV-3, one of the most predominant types in children, HAdV-55 is a reemergent pathogen associated with more severe community-acquired pneumonia (CAP) in adults, especially in military camps. However, the infectivity and pathogenicity differences between these viruses remain unknown as in vivo models are not available. Here, we report a novel system utilizing human embryonic stem cells-derived 3-dimensional airway organoids (hAWOs) and alveolar organoids (hALOs) to investigate these two viruses. Firstly, HAdV-55 replicated more robustly than HAdV-3. Secondly, cell tropism analysis in hAWOs and hALOs by immunofluorescence staining revealed that HAdV-55 infected more airway and alveolar stem cells (basal and AT2 cells) than HAdV-3, which may lead to impairment of self-renewal functions post-injury and the loss of cell differentiation in lungs. Additionally, the viral life cycles of HAdV-3 and -55 in organoids were also observed using Transmission Electron Microscopy. This study presents a useful pair of lung organoids for modeling infection and replication differences between respiratory pathogens, illustrating that HAdV-55 has relatively higher replication efficiency and more specific cell tropism in human lung organoids than HAdV-3, which may result in relatively higher pathogenicity and virulence of HAdV-55 in human lungs. The model system is also suitable for evaluating potential antiviral drugs, as demonstrated with cidofovir. IMPORTANCE Human adenovirus (HAdV) infections are a major threat worldwide. HAdV-3 is one of the most predominant respiratory pathogen types found in children. Many clinical studies have reported that HAdV-3 causes less severe disease. In contrast, HAdV-55, a reemergent acute respiratory disease pathogen, is associated with severe community-acquired pneumonia in adults. Currently, no ideal in vivo models are available for studying HAdVs. Therefore, the mechanism of infectivity and pathogenicity differences between human adenoviruses remain unknown. In this study, a useful pair of 3-dimensional (3D) airway organoids (hAWOs) and alveolar organoids (hALOs) were developed to serve as a model. The life cycles of HAdV-3 and HAdV-55 in these human lung organoids were documented for the first time. These 3D organoids harbor different cell types, which are similar to the ones found in humans. This allows for the study of the natural target cells for infection. The finding of differences in replication efficiency and cell tropism between HAdV-55 and -3 may provide insights into the mechanism of clinical pathogenicity differences between these two important HAdV types. Additionally, this study provides a viable and effective in vitro tool for evaluating potential anti-adenoviral treatments.

Enzymatic independent role of sphingosine kinase 2 in regulating the expression of type I interferon during influenza A virus infection.

Influenza virus has the ability to circumvent host innate immune system through regulating certain host factors for its effective propagation. However, the detailed mechanism is still not fully understood. Here, we report that a host sphingolipid metabolism-related factor, sphingosine kinase 2 (SPHK2), upregulated during influenza A virus (IAV) infection, promotes IAV infection in an enzymatic independent manner. The enhancement of the virus replication is not abolished in the catalytic-incompetent SPHK2 (G212E) overexpressing cells. Intriguingly, the sphingosine-1-phosphate (S1P) related factor HDAC1 also plays a crucial role in SPHK2-mediated IAV infection. We found that SPHK2 cannot facilitate IAV infection in HDAC1 deficient cells. More importantly, SPHK2 overexpression diminishes the IFN-ß promoter activity upon IAV infection, resulting in the suppression of type I IFN signaling. Furthermore, ChIP-qPCR assay revealed that SPHK2 interacts with IFN-ß promoter through the binding of demethylase TET3, but not with the other promoters regulated by TET3, such as TGF-ß1 and IL6 promoters. The specific regulation of SPHK2 on IFN-ß promoter through TET3 can in turn recruit HDAC1 to the IFN-ß promoter, enhancing the deacetylation of IFN-ß promoter, therefore leading to the inhibition of IFN-ß transcription. These findings reveal an enzymatic independent mechanism on host SPHK2, which associates with TET3 and HDAC1 to negatively regulate type I IFN expression and thus facilitates IAV propagation.

5S rRNA pseudogene transcripts are associated with interferon production and inflammatory responses in alcohol-associated hepatitis.

BACKGROUND AND AIMS: Interferon (IFN) signaling is critical to the pathogenesis of alcohol-associated hepatitis (AH), yet the mechanisms for activation of this system are elusive. We hypothesize that host-derived 5S rRNA pseudogene (RNA5SP) transcripts regulate IFN production and modify immunity in AH. APPROACH AND RESULTS: Mining of transcriptomic datasets revealed that in patients with severe alcohol-associated hepatitis (sAH), hepatic expression of genes regulated by IFNs was perturbed and gene sets involved in IFN production were enriched. RNA5SP transcripts were also increased and correlated with expression of type I IFNs. Interestingly, inflammatory mediators upregulated in sAH, but not in other liver diseases, were positively correlated with certain RNA5SP transcripts. Real-time quantitative PCR demonstrated that RNA5SP transcripts were upregulated in peripheral blood mononuclear cells (PBMCs) from patients with sAH. In sAH livers, increased 5S rRNA and reduced nuclear MAF1 (MAF1 homolog, negative regulator of RNA polymerase III) protein suggested a higher activity of RNA polymerase III (Pol III); inhibition of Pol III reduced RNA5SP expression in monocytic THP-1 cells. Expression of several RNA5SP transcript-interacting proteins was downregulated in sAH, potentially unmasking transcripts to immunosensors. Indeed, siRNA knockdown of interacting proteins potentiated the immunostimulatory activity of RNA5SP transcripts. Molecular interaction and cell viability assays demonstrated that RNA5SP transcripts adopted Z-conformation and contributed to ZBP1-mediated caspase-independent cell death. CONCLUSIONS: Increased expression and binding availability of RNA5SP transcripts was associated with hepatic IFN production and inflammation in sAH. These data identify RNA5SP transcripts as a potential target to mitigate inflammation and hepatocellular injury in AH.

Macrophage-derived MLKL in alcohol-associated liver disease: Regulation of phagocytosis.

BACKGROUND AND AIMS: Mixed lineage kinase domain-like pseudokinase (MLKL), a key terminal effector of necroptosis, also plays a role in intracellular vesicle trafficking that is critical for regulating liver inflammation and injury in alcohol-associated liver disease (ALD). Although receptor interacting protein kinase 3 (Rip3)-/- mice are completely protected from ethanol-induced liver injury, Mlkl-/- mice are only partially protected. Therefore, we hypothesized that cell-specific functions of MLKL may contribute to ethanol-induced injury. APPROACH AND RESULTS: Bone marrow transplants between Mlkl-/- mice and littermates were conducted to distinguish the role of myeloid versus nonmyeloid Mlkl in the Gao-binge model of ALD. Ethanol-induced hepatic injury, steatosis, and inflammation were exacerbated in Mlkl-/- →wild-type (WT) mice, whereas Mlkl deficiency in nonmyeloid cells (WT→ Mlkl-/- ) had no effect on Gao-binge ethanol-induced injury. Importantly, Mlkl deficiency in myeloid cells exacerbated ethanol-mediated bacterial burden and accumulation of immune cells in livers. Mechanistically, challenging macrophages with lipopolysaccharide (LPS) induced signal transducer and activator of transcription 1-mediated expression and phosphorylation of MLKL, as well as translocation and oligomerization of MLKL to intracellular compartments, including phagosomes and lysosomes but not plasma membrane. Importantly, pharmacological or genetic inhibition of MLKL suppressed the phagocytic capability of primary mouse Kupffer cells (KCs) at baseline and in response to LPS with/without ethanol as well as peripheral monocytes isolated from both healthy controls and patients with alcohol-associated hepatitis. Further, in vivo studies revealed that KCs of Mlkl-/- mice phagocytosed fewer bioparticles than KCs of WT mice. CONCLUSION: Together, these data indicate that myeloid MLKL restricts ethanol-induced liver inflammation and injury by regulating hepatic immune cell homeostasis and macrophage phagocytosis.

A disposable paper-based electrochemical biosensor decorated by electrospun cellulose acetate nanofibers for highly sensitive bio-detection.

Paper-based electrochemical sensors have the characteristics of flexibility, biocompatibility, environmental protection, low cost, wide availability, and hydropathy, which make them very suitable for the development and application of biological detection. This work proposes electrospun cellulose acetate nanofiber (CA NF)-decorated paper-based screen-printed (PBSP) electrode electrochemical sensors. The CA NFs were directly collected on the PBSP electrode through an electrospinning technique at an optimized voltage of 16 kV for 10 min. The sensor was functionalized with different bio-sensitive materials for detecting different targets, and its sensing capability was evaluated by CV, DPV, and chronoamperometry methods. The test results demonstrated that the CA NFs enhanced the detection sensitivity of the PBSP electrode, and the sensor showed good stability, repeatability, and specificity (p < 0.01, N = 3). The electrochemical sensing of the CA NF-decorated PBSP electrode exhibited a short detection duration of ∼5-7 min and detection ranges of 1 nmol mL-1-100 µmol mL-1, 100 fg mL-1-10 µg mL-1, and 1.5 × 102-106 CFU mL-1 and limits of detection of 0.71 nmol mL-1, 89.1 fg mL-1, and 30 CFU mL-1 for glucose, Ag85B protein, and E. coli O157:H7, respectively. These CA NF-decorated PBSP sensors can be used as a general electrochemical tool to detect, for example, organic substances, proteins, and bacteria, which are expected to achieve point-of-care testing of pathogenic microorganisms and have wide application prospects in biomedicine, clinical diagnosis, environmental monitoring, and food safety.

Identification and candidate analysis of a new brown planthopper resistance locus in an Indian landrace of rice, paedai kalibungga.

The brown planthopper (Nilaparvata lugens Stål, BPH) is the most destructive pest of rice (Oryza sativa L.). Utilizing resistant rice cultivars that harbor resistance gene/s is an effective strategy for integrated pest management. Due to the co-evolution of BPH and rice, a single resistance gene may fail because of changes in the virulent BPH population. Thus, it is urgent to explore and map novel BPH resistance genes in rice germplasm. Previously, an indica landrace from India, Paedai kalibungga (PK), demonstrated high resistance to BPH in both in Wuhan and Fuzhou, China. To map BPH resistance genes from PK, a BC1F2:3 population derived from crosses of PK and a susceptible parent, Zhenshan 97 (ZS97), was developed and evaluated for BPH resistance. A novel BPH resistance locus, BPH39, was mapped on the short arm of rice chromosome 6 using next-generation sequencing-based bulked segregant analysis (BSA-seq). BPH39 was validated using flanking markers within the locus. Furthermore, near-isogenic lines carrying BPH39 (NIL-BPH39) were developed in the ZS97 background. NIL-BPH39 exhibited the physiological mechanisms of antibiosis and preference toward BPH. BPH39 was finally delimited to an interval of 84 Kb ranging from 1.07 to 1.15 Mb. Six candidate genes were identified in this region. Two of them (LOC_Os06g02930 and LOC_Os06g03030) encode proteins with a similar short consensus repeat (SCR) domain, which displayed many variations leading to amino acid substitutions and showed higher expression levels in NIL-BPH39. Thus, these two genes are considered reliable candidate genes for BPH39. Additionally, transcriptome sequencing, DEGs analysis, and gene RT-qPCR verification preliminary revealed that BPH39 may be involved in the jasmonic acid (JA) signaling pathway, thus mediating the molecular mechanism of BPH resistance. This work will facilitate map-based cloning and marker-assisted selection for the locus in breeding programs targeting BPH resistance. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01485-6.

China's response to a national land-system sustainability emergency.

China has responded to a national land-system sustainability emergency via an integrated portfolio of large-scale programmes. Here we review 16 sustainability programmes, which invested US$378.5 billion (in 2015 US$), covered 623.9 million hectares of land and involved over 500 million people, mostly since 1998. We find overwhelmingly that the interventions improved the sustainability of China's rural land systems, but the impacts are nuanced and adverse outcomes have occurred. We identify some key characteristics of programme success, potential risks to their durability, and future research needs. We suggest directions for China and other nations as they progress towards the Sustainable Development Goals of the United Nations' Agenda 2030.

miRNA-383-5p Regulated Migration and Invasion of Tumor Cells by Inhibiting NCKAP1 Expression in Gastric Cancer.

Gastric cancer (GC) is the second deadliest disease in Asia, so it is crucial to find its promising therapeutic targets. The expression profile data of miR383-5p in the Cancer Genome Atlas (TCGA) were analyzed. The expression levels of miR383-5p in the collected clinical tissue samples and peripheral blood samples were examined by qPCR, and the relationship between its expression and the clinical data of patients was evaluated. MiR383-5p was overexpressed in the AGS cells, and cell biology assays, such as Transwell, were performed to detect the cell proliferation, migration, invasion and other cell biology abilities of miR383-5p. Target prediction and dual luciferase reporter gene assay were performed to find and validate the target genes of miR383-5p. The expression and activity of MMP and related proteins after overexpression of miR383-5p and NCKAP1 were detected by WB and gelatin zymography assay. The expression of miR383-5p was down-regulated in GC tissues, and its low expression was associated with lymph node metastasis. Restoration of miR383-5p expression in GC cells can inhibit the invasion and migration abilities of GC cells. MiR383-5p negatively regulated NCKAP1 through direct interaction with the 3'UTR sequence of NCKAP1. The overexpression of NCKAP1 can improve the migration and invasion abilities of GC cells, whereas overexpression of miR383-5p can inhibit growth of the aforementioned abilities of GC cells induced by NCKAP1 overexpression. The overexpression of NCKAP1 can increase the expression level and activity of MMP2, while the overexpression of miR383-5p can inhibit the increase of MMP2 expression level and activity in GC cells induced by NCKAP1 overexpression. NCKAP1 is a target gene of miR383-5p, and miR383-5p could be a valuable therapeutic target for stomach adenocarcinoma.

Identifying broken linkages coupling water availability and dryland urbanization for sustainability: The case of the Phoenix metropolitan region, USA.

One third of the world's largest cities are located in drylands, where much of future urbanization is projected to occur. This is paradoxical and unsustainable considering water scarcity in drylands, which is exacerbated by climate change. Thus, it is critical to better understand why and how dryland urbanization and water scarcity are decoupled so that sustainable measures can be designed. Focusing on the Phoenix Metropolitan Area (PMA) of the United States, we addressed the following questions: 1) What are the relative influences of water and economic factors on urbanization in recent decades? 2) Which linkages connecting water storage to urban development have been decoupled? and 3) How can water availability and development be better coupled to improve regional sustainability? We tested the relationships between economic factors, water availability, and urbanization, with Pearson Correlation Analysis and Structural Equation Modeling. We found that, from 1986 to 2019, urban population growth and urban land expansion in the PMA were driven by economic factors, and not influenced by fluctuations in water supply. We identified specific broken linkages among water storage, water deliveries, municipal water supply, and urbanization, which must be coupled to enforce water availability constraints on urban expansion in the context of climate change. Our study has important implications for dryland urban sustainability as urbanization on borrowed water is, by definition, unsustainable.

Plant virology in the 21st century in China: Recent advances and future directions.

Plant viruses are a group of intracellular pathogens that persistently threaten global food security. Significant advances in plant virology have been achieved by Chinese scientists over the last 20 years, including basic research and technologies for preventing and controlling plant viral diseases. Here, we review these milestones and advances, including the identification of new crop-infecting viruses, dissection of pathogenic mechanisms of multiple viruses, examination of multilayered interactions among viruses, their host plants, and virus-transmitting arthropod vectors, and in-depth interrogation of plant-encoded resistance and susceptibility determinants. Notably, various plant virus-based vectors have also been successfully developed for gene function studies and target gene expression in plants. We also recommend future plant virology studies in China.

Discovery of Alloy Catalysts Beyond Pd for Selective Hydrogenation of Reformate via First-Principle Screening with Consideration of H-Coverage.

The highly selective hydrogenation to remove olefins is a significant refining approach for the reformate. Herein, a library of transition metal for reformate hydrogenation is tested experimentally to validate the predictive level of catalytic activity from our theoretical framework, which combines ab initio calculations and microkinetic modeling, with consideration of surface H-coverage effect on hydrogenation kinetics. The favorable H coverage of specific alloy surface under relevant hydrogenation condition, is found to be determined by its corresponding alloy composition. Besides, olefin hydrogenation rate is determined as a function of two descriptors, i.e. H coverage and binding energies of atomic hydrogen, paving the way to computationally screen on metal component in the periodic table. Evaluation of 172 bimetallic alloys based on the activity volcano map, as well as benzene hydrogenation rate, identifies prospective superior candidates and experimentally confirms that Zn3Ir1 outperforms pure Pd catalysts for the selective hydrogenation refining of reformate. The insights into H-coverage-related microkinetic modelling have enabled us to both theoretically understand experimental findings and identify novel catalysts, thus, bridging the gap between first-principle simulations and industrial applications. This work provides useful guidance for experimental catalyst design, which can be easily extended to other hydrogenation reaction.

Macrophages enhance cisplatin resistance in gastric cancer through the transfer of circTEX2.

Cisplatin-based chemotherapy is often used in advanced gastric cancer (GC) treatment, yet resistance to cisplatin may lead to treatment failure. Mechanisms underlying cisplatin resistance remain unclear. Recent evidence highlighted the role of macrophages in cancer chemoresistance. Macrophage-derived exosomes were shown to facilitate intercellular communication. Here, we investigated the cisplatin resistance mechanism based on macrophage-derived exosomes in gastric cancer. Cell growth and apoptosis detection experiments revealed that M2-polarized macrophages increased the resistance of GC cells to cisplatin. qRT-PCR, RNAase R assay, actinomycin D assay and cell nucleo-cytoplasmic separation experiments confirmed the existence of circTEX2 in macrophage cytoplasm, with a higher expression level in M2 macrophages than that in M1 macrophages. Further experiments showed that circTEX2 acted as microRNA sponges for miR-145 and regulated the expression of ATP Binding Cassette Subfamily C Member 1 (ABCC1). Inhibition of the circTEX2/miR-145/ABCC1 axis blocked the cisplatin resistance of gastric cancer induced by M2 macrophages, as evidenced by in vitro and in vivo experiments. In conclusion, our research suggests that the exosomal transfer of M2 macrophage-derived circTEX2 enhances cisplatin resistance in gastric cancer through miR-145/ABCC1. Additionally, communication between macrophages and cancer cells via exosomes may be a promising therapeutic target for the treatment of cisplatin-resistant gastric cancer.

DENV NS1 and MMP-9 cooperate to induce vascular leakage by altering endothelial cell adhesion and tight junction.

Dengue virus (DENV) is a mosquito-borne pathogen that causes a spectrum of diseases including life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Vascular leakage is a common clinical crisis in DHF/DSS patients and highly associated with increased endothelial permeability. The presence of vascular leakage causes hypotension, circulatory failure, and disseminated intravascular coagulation as the disease progresses of DHF/DSS patients, which can lead to the death of patients. However, the mechanisms by which DENV infection caused the vascular leakage are not fully understood. This study reveals a distinct mechanism by which DENV induces endothelial permeability and vascular leakage in human endothelial cells and mice tissues. We initially show that DENV2 promotes the matrix metalloproteinase-9 (MMP-9) expression and secretion in DHF patients' sera, peripheral blood mononuclear cells (PBMCs), and macrophages. This study further reveals that DENV non-structural protein 1 (NS1) induces MMP-9 expression through activating the nuclear factor κB (NF-κB) signaling pathway. Additionally, NS1 facilitates the MMP-9 enzymatic activity, which alters the adhesion and tight junction and vascular leakage in human endothelial cells and mouse tissues. Moreover, NS1 recruits MMP-9 to interact with ß-catenin and Zona occludens protein-1/2 (ZO-1 and ZO-2) and to degrade the important adhesion and tight junction proteins, thereby inducing endothelial hyperpermeability and vascular leakage in human endothelial cells and mouse tissues. Thus, we reveal that DENV NS1 and MMP-9 cooperatively induce vascular leakage by impairing endothelial cell adhesion and tight junction, and suggest that MMP-9 may serve as a potential target for the treatment of hypovolemia in DSS/DHF patients.

Inhibition of PIKFYVE kinase interferes ESCRT pathway to suppress RNA virus replication.

Endosomal sorting complex required for transport (ESCRT) is essential in the functional operation of endosomal transport in envelopment and budding of enveloped RNA viruses. However, in nonenveloped RNA viruses such as enteroviruses of the Picornaviridae family, the precise function of ESCRT pathway in viral replication remains elusive. Here, we initially evaluated that the ESCRT pathway is important for viral replication upon enterovirus 71 (EV71) infection. Furthermore, we discovered that YM201636, a specific inhibitor of phosphoinositide kinase, FYVE finger containing (PIKFYVE) kinase, significantly suppressed EV71 replication and virus-induced inflammation in vitro and in vivo. Mechanistically, YM201636 inhibits PIKFYVE kinase to block the ESCRT pathway and endosomal transport, leading to the disruption of viral entry and replication complex in subcellular components and ultimately repression of intracellular RNA virus replication and virus-induced inflammatory responses. Further studies found that YM201636 broadly represses the replication of other RNA viruses, including coxsackievirus B3 (CVB3), poliovirus 1 (PV1), echovirus 11 (E11), Zika virus (ZIKV), and vesicular stomatitis virus (VSV), rather than DNA viruses, including adenovirus 3 (ADV3) and hepatitis B virus (HBV). Our findings shed light on the mechanism underlying PIKFYVE-modulated ESCRT pathway involved in RNA virus replication, and also provide a prospective antiviral therapy during RNA viruses infections.