HCV 5-Methylcytosine Enhances Viral RNA Replication through Interaction with m5C Reader YBX1.

Hepatitis C virus (HCV) is a positive-stranded RNA virus that mainly causes chronic hepatitis, cirrhosis and hepatocellular carcinoma. Recently we confirmed m5C modifications within NS5A gene of HCV RNA genome. However, the roles of the m5C modification and its interaction with host proteins in regulating HCV's life cycle, remain unexplored. Here, we demonstrate that HCV infection enhances the expression of the host m5C reader YBX1 through the transcription factor MAX. YBX1 acts as an m5C reader, recognizing the m5C-modified NS5A C7525 site in the HCV RNA genome and significantly enhancing HCV RNA stability. This m5C-modification is also required for YBX1 colocalization with lipid droplets and HCV Core protein. Moreover, YBX1 facilitates HCV RNA replication, as well as viral assembly/budding. The tryptophan residue at position 65 (W65) of YBX1 is critical for these functions. Knockout of YBX1 or the application of YBX1 inhibitor SU056 suppresses HCV RNA replication and viral protein translation. To our knowledge, this is the first report demonstrating that the interaction between host m5C reader YBX1 and HCV RNA m5C methylation facilitates viral replication. Therefore, hepatic-YBX1 knockdown holds promise as a potential host-directed strategy for HCV therapy.

IL-37 protects against house dust mite-induced airway inflammation and airway epithelial barrier dysfunction via inhibiting store-operated calcium entry.

BACKGROUND: Airway epithelial barrier dysfunction has been proved to contribute to the development of type 2 inflammation of asthma. Interleukin (IL)-37 is a negative regulator of immune responses and allergic airway inflammation. However, whether IL-37 has any effect on airway epithelial barrier has been unknown. METHODS: We evaluated the role of IL-37 in both mouse model and cultured 16HBE cells. Histology and ELISA assays were used to evaluate airway inflammation. FITC-dextran permeability assay was used to evaluate the airway epithelial barrier function. Immunofluorescence, western blot and quantitative Real-Time PCR (RT-PCR) were used to evaluate the distribution and expression of tight junction proteins. RT-PCR and Ca2+ fluorescence measurement were used to evaluate the mRNA expression and activity of store-operated calcium entry (SOCE). RESULTS: IL-37 inhibited house dust mite (HDM)-induced airway inflammation and decreased the levels of IgE in serum and type 2 cytokines in bronchoalveolar lavage fluid (BALF) compared to asthmatic mice. IL-37 protected against HDM-induced airway epithelial barrier dysfunction, including reduced leakage of FITC-dextran, enhanced expression of TJ proteins, and restored the membrane distribution of TJ proteins. Moreover, IL-37 decreased the level of IL-33 in the BALF of asthmatic mice and the supernatants of HDM-treated 16HBE cells. IL-37 decreased the peak level of Ca2+ fluorescence induced by thapsigargin and HDM, and inhibited the mRNA expression of Orai1, suggesting an inhibiting effect of IL-37 on SOCE in airway epithelial cells. CONCLUSION: IL-37 plays a protective role in airway inflammation and HDM-induced airway epithelial barrier dysfunction by inhibiting SOCE.

Macrophages exploit the mannose receptor and JAK-STAT1-MHC-II pathway to drive antigen presentation and the antimycobacterial immune response after BCG vaccination.

Tuberculosis (TB), caused by Mycobacterium tuberculosis ( M. tb), remains one of the leading causes of fatal infectious diseases worldwide. The only licensed vaccine, Mycobacterium bovis Bacillus Calmette-Guérin (BCG), has variable efficacy against TB in adults. Insufficiency of immune cell function diminishes the protective effects of the BCG vaccine. It is critical to clarify the mechanism underlying the antimycobacterial immune response during BCG vaccination. Macrophage mannose receptor (MR) is important for enhancing the uptake and processing of glycoconjugated antigens from pathogens for presentation to T cells, but the roles of macrophage MR in the BCG-induced immune response against M. tb are not yet clear. Here, we discover that macrophage MR deficiency impairs the antimycobacterial immune response in BCG-vaccinated mice. Mechanistically, macrophage MR triggers JAK-STAT1 signaling, which promotes antigen presentation via upregulated MHC-II and induces IL-12 production by macrophages, contributing to CD4 + T cell activation and IFN-γ production. MR deficiency in macrophages reduces the vaccine efficacy of BCG and increases susceptibility to M. tb H37Ra challenge in mice. Our results suggest that MR is critical for macrophage antigen presentation and the antimycobacterial immune response to BCG vaccination and offer valuable guidance for the preventive strategy of BCG immunization.

Deformation and Failure Mechanisms of Element-Substituted Thermoelectric Type-I and Type-VIII Clathrates.

Clathrates are potential "phonon-glass, electron-crystal" thermoelectric semiconductors, whose structure of polyhedron stacks is very attractive. However, their mechanical properties have not yet met the requirements of industrial applications. Here, we report the ideal strength of element-substituted type-I and type-VIII clathrates and the shear deformation mechanism by using density functional theory. The results show that the framework element is the determinant of the intrinsic mechanical properties of the clathrates and is affected by sequential weakening of Si-Ge-Sn. The highest ideal shear strength is 8.71 GPa for I-Ba8Au6Si40 along the (110)/[001] slip system, which is attributed to the formation of higher-energy Si-Si covalent bonds. Meanwhile, the ideal shear strength of Ba-filled I/VIII clathrates (4.51/2.65 GPa) is higher than that of Sr-filled clathrates (3.64 GPa/1.91 GPa). In addition, the strength and ultimate strain of VIII-Ba8Ga16Sn30 can be significantly increased by the structural coordination accommodating with the stiffness of the Ga-Ge bond to achieve simultaneous bond breaking. Our findings demonstrate that the element substitution strategy is an effective approach for designing highly robust clathrates.

Enhancing the flame retardancy of polylactic acid nonwoven fabric through solvent-free transparent coating.

Polylactic acid (PLA) nonwovens, recognized as eco-friendly substitutes for petroleum-based synthetic fibers, face a significant challenge due to their inherent flammability. This work addresses this concern by synthesizing a hyperbranched polyphosphoramide flame retardant (TPDT) through a one-step polycondensation process without using solvent and catalyst. TPDT is subsequently applied to PLA nonwovens using a dip-pad finishing technique. Notably, with a mere 7 wt% weight gain of TPDT, the PLA nonwovens exhibit a substantial increase in the limited oxygen index (LOI) value, reaching 32.3 %. Furthermore, the damaged area in the vertical burning test is reduced by approximately 69.2 %. In the cone calorimeter test, 17 wt% weight gain of TPDT results in a 51.4 % decrease in peak heat release rate and a 56.0 % reduction in total heat release compared to the control PLA. Additionally, char residue increases from 1.5 wt% to 31.1 wt% after combustion. The strong affinity between TPDT and PLA molecules persists even after repeated abrasion, ensuring sustained flame retardancy. Importantly, the introduction of TPDT also imparts increased softness to the PLA nonwovens. This work addresses this concern by synthesizing a hyperbranched polyphosphoramide flame retardant (TPDT) through a solvent-free, catalyst-free, and one-step polycondensation process.

CRDet: A circle representation detector for lung granulomas based on multi-scale attention features with center point calibration.

Lung granuloma is a very common lung disease, and its specific diagnosis is important for determining the exact cause of the disease as well as the prognosis of the patient. And, an effective lung granuloma detection model based on computer-aided diagnostics (CAD) can help pathologists to localize granulomas, thereby improving the efficiency of the specific diagnosis. However, for lung granuloma detection models based on CAD, the significant size differences between granulomas and how to better utilize the morphological features of granulomas are both critical challenges to be addressed. In this paper, we propose an automatic method CRDet to localize granulomas in histopathological images and deal with these challenges. We first introduce the multi-scale feature extraction network with self-attention to extract features at different scales at the same time. Then, the features will be converted to circle representations of granulomas by circle representation detection heads to achieve the alignment of features and ground truth. In this way, we can also more effectively use the circular morphological features of granulomas. Finally, we propose a center point calibration method at the inference stage to further optimize the circle representation. For model evaluation, we built a lung granuloma circle representation dataset named LGCR, including 288 images from 50 subjects. Our method yielded 0.316 mAP and 0.571 mAR, outperforming the state-of-the-art object detection methods on our proposed LGCR.

EGFR core fucosylation, induced by hepatitis C virus, promotes TRIM40-mediated-RIG-I ubiquitination and suppresses interferon-I antiviral defenses.

Aberrant N-glycosylation has been implicated in viral diseases. Alpha-(1,6)-fucosyltransferase (FUT8) is the sole enzyme responsible for core fucosylation of N-glycans during glycoprotein biosynthesis. Here we find that multiple viral envelope proteins, including Hepatitis C Virus (HCV)-E2, Vesicular stomatitis virus (VSV)-G, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-Spike and human immunodeficiency virus (HIV)-gp120, enhance FUT8 expression and core fucosylation. HCV-E2 manipulates host transcription factor SNAIL to induce FUT8 expression through EGFR-AKT-SNAIL activation. The aberrant increased-FUT8 expression promotes TRIM40-mediated RIG-I K48-ubiquitination and suppresses the antiviral interferon (IFN)-I response through core fucosylated-EGFR-JAK1-STAT3-RIG-I signaling. FUT8 inhibitor 2FF, N-glycosylation site-specific mutation (Q352AT) of EGFR, and tissue-targeted Fut8 silencing significantly increase antiviral IFN-I responses and suppress RNA viral replication, suggesting that core fucosylation mediated by FUT8 is critical for antiviral innate immunity. These findings reveal an immune evasion mechanism in which virus-induced FUT8 suppresses endogenous RIG-I-mediated antiviral defenses by enhancing core fucosylated EGFR-mediated activation.

The effect of FOXP3 genetic polymorphisms on correlations with hepatitis B virus-hepatocellular carcinoma: A case-control study.

Background: Previous studies have reported that transcription factor forkhead box protein 3 (FOXP3) polymorphisms are correlated with the progress of some cancers, but the relationships between the FOXP3 polymorphisms and hepatocellular carcinoma (HCC) risk remain unclear. Method: Genotypes were detected in156 hepatitis B virus (HBV)-HCC patients, 109 HBV-liver cirrhosis (LC) patients, 125 chronic hepatitis B (CHB) patients, and 188 healthy controls. The FOXP3 rs3761547 and rs3761548 polymorphisms were genotyped by polymerase chain reaction (PCR) combined with restriction fragment length polymorphism, and the rs2232365 polymorphism was genotyped using PCR with sequence-specific primers. Results: We did not obtain any significant results with the FOXP3 rs3761547, rs3761548, and rs2232365 polymorphisms in groups of patients compared to healthy controls (all p > 0.05), no matter the overall group or subgroup. Conclusions: Our findings suggest that the FOXP3 polymorphisms at rs3761547, rs3761548, and rs2232365 were not related to HBV-HCC risk in the Chinese population.

New insights into transcriptome variation during cattle adipocyte adipogenesis by direct RNA sequencing.

We performed direct RNA sequencing (DRS) together with PCR-amplified cDNA long and short read sequencing for cattle adipocyte at different stages. We proved that the DRS was with advantages to avoid artificial transcripts and questionable exitrons. Totally, we obtained 68,124 transcripts with information of alternative splicing, poly (A) length and mRNA modification. The number of transcripts for adipogenesis was expanded by alternative splicing, which lead regulation mechanisms far more complex than ever known. We detected 891 differentially expressed genes (DEGs). However, 62.78% transcripts of DEGs were not significantly differentially expressed, and 248 transcripts showed opposite changing directions with their genes. The poly (A) tail became globally shorter in differentiated adipocyte than in primary adipocyte, and had a weak negative correlation with gene/transcript expression. Moreover, the study of different mRNA modifications implied their potential roles in gene expression and alternative splicing. Overall, our study promoted better understanding of adipogenesis mechanisms in cattle adipocytes.

Two novel transporters NtNRAMP6a and NtNRAMP6b are involved in cadmium transport in tobacco (Nicotiana tabacum L.).

Plant natural resistance-associated macrophage protein (NRAMP) plays important roles in metal transport and tolerance. Tobacco is a typical cadmium (Cd) accumulator, while research on NRAMP in tobacco has been limited. In the current study, two novel NRAMP genes (NtNRAMP6a and NtNRAMP6b) were identified from the allotetraploid plant Nicotiana tabacum L. Real time‒PCR and GUS (ß-glucuronidase) staining results showed that the two genes were expressed in roots, stems, leaves and flowers and induced by Cd stress. Subcellular localization revealed that they were located in the plasma membrane. Heterologously expressed NtNRAMP6a and NtNRAMP6b significantly increased the Cd sensitivity of the Δycf1 mutant, indicating that NtNRAMP6a and NtNRAMP6b had Cd transport functions in yeast. The difference in the manganese (Mn) transport activity of the two genes was demonstrated by point mutation, which was caused by the difference in the 18th amino acid. NRAMP6-N18K is a new key active site for manganese transport. After 50 µM Cd treatment for 7 days, the contents of Cd and Mn of the ntnramp6a/6b mutants was significantly lower than those of wild type in shoots, while the contents in roots were higher. Additionally, the mutant lines showed higher chorphyll contentration and lighter leaf damage. Knockout of NtNRAMP6a and NtNRAMP6b reduced Cd and Mn accumulation in tobacco shoots by influence root-to-shoot translocation. This provides new idea for cultivating tobacco varieties with low cadmium accumulation and high cadmium tolerance.

Intermittent fasting protects against food allergy in a murine model via regulating gut microbiota.

Background: The prevalence of food allergy (FA) is increasing. Decreases in the diversity of gut microbiota may contribute to the pathogenesis of FA by regulating IgE production of B cells. Intermittent fasting (IF) is a popular diet with the potential to regulate glucose metabolism, boosting immune memory and optimizing gut microbiota. The potential effect of long-term IF on the prevention and treatment of FA is still unknown. Methods: Two IF protocols (16 h fasting/8 h feeding and 24 h fasting/24 h feeding) were conducted on mice for 56 days, while the control mice were free to intake food (free diet group, FrD). To construct the FA model, all mice were sensitized and intragastrical challenged with ovalbumin (OVA) during the second half of IF (day 28 to day 56). Rectal temperature reduction and diarrhea were recorded to evaluate the symptoms of FA. Levels of serum IgE, IgG1, Th1/Th2 cytokines, mRNA expression of spleen T cell related transcriptional factors, and cytokines were examined. H&E, immunofluorescence, and toluidine blue staining were used to assess the structural changes of ileum villi. The composition and abundance of gut microbiota were analyzed by 16srRNA sequencing in cecum feces. Results: The diarrhea score and rectal temperature reduction were lower in the two fasting groups compared to the FrD groups. Fasting was associated with lower levels of serum OVA-sIgE, OVA-sIgG1, interleukin (IL)-4 and IL-5, and mRNA expression of IL-4, IL-5, and IL-10 in the spleen. While no significant association was observed in interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-6, IL-2 levels. Less mast cell infiltration in ileum was observed in the 16h/8h fasting group compared to the FrD group. ZO-1 expression in the ileum of the two fasting groups was higher in IF mice. The 24h/24h fasting reshaped the gut microbiota, with a higher abundance of Alistipes and Rikenellaceae strains compared to the other groups. Conclusion: In an OVA-induced mice FA model, long-term IF may attenuate FA by reducing Th2 inflammation, maintaining the integrity of the intestinal epithelial barrier, and preventing gut dysbiosis.

Interleukin-16 genetic polymorphisms in Guangxi Chinese with hepatitis B virus-related liver cirrhosis.

BACKGROUND: Our previous study has reported that interleukin-16 (IL-16) genetic polymorphisms are significantly related to chronic hepatitis B (CHB) and hepatitis B virus-related (HBV-related) hepatocellular carcinoma (HCC). As CHB, liver cirrhosis (LC), and HCC are development processes, this study aimed to determine genetic correlation of IL-16 polymorphisms with HBV-related LC in a Chinese population. METHODS: IL-16 gene rs11556218, rs4072111, and rs4778889 polymorphism in 129 patients with HBV-related LC and 168 healthy individuals were genotyped via polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). PCR-RFLP results were verified by DNA sequencing. RESULTS: The allelic and genotypic distributions of IL-16 rs11556218, rs4072111, and rs4778889 polymorphisms in HBV-related LC patients showed no significant difference from those in healthy controls. Furthermore, no relationship was observed between the haplotype distribution and susceptibility to HBV-related LC. CONCLUSIONS: This work provided the first evidence that the IL-16 genetic polymorphisms may not be associated with HBV-related LC risk.

The Transcriptome-Wide Mapping of 2-Methylthio-N6-isopentenyladenosine at Single-Base Resolution.

Hundreds of modified bases have been identified and enzymatically modified to transfer RNAs (tRNAs) to regulate RNA function in various organisms. 2-Methylthio-N6-isopentenyladenosine (ms2i6A), a hypermodified base found at tRNA position 37, exists in both prokaryotes and eukaryotes. ms2i6A is traditionally identified by separating and digesting each tRNA from total RNA using RNA mass spectrometry. A transcriptome-wide and single-base resolution method that enables absolute mapping of ms2i6A along with analysis of its distribution in different RNAs is lacking. Here, through chemoselective methylthio group bioconjugation, we introduce a new approach (redox activated chemical tagging sequencing, ReACT-seq) to detect ms2i6A transcriptome-wide at single-base resolution. Using the chemoselectivity between the methylthio group and oxaziridine group, ms2i6A is bio-orthogonally tagged with an azide group without interference of canonical nucleotides, advancing enrichment of methylthio group modified RNAs prior to sequencing. ReACT-seq was demonstrated on nine known tRNAs and proved to be highly accurate, and the reverse transcription stop (RT-stop) character enables ReACT-seq detection at single-base resolution. In addition, ReACT-seq identified that the modification of ms2i6A is conservative and may not exist in other RNAs.

Engineered Phage with Aggregation-Induced Emission Photosensitizer in Cocktail Therapy against Sepsis.

Sepsis, a widely recognized disease, is characterized by multiple pathogen infections. Therefore, it is imperative to develop methods that can efficiently identify and neutralize pathogen species. Phage cocktail therapy utilizes the host specificity of phages to adapt to infect resistant bacteria. However, its low sterilization stability efficiency and lack of imaging units seriously restrict its application. Here, a novel strategy combining the aggregation-induced emission photosensitizer (AIE-PS) TBTCP-PMB with phages through a nucleophilic substitution reaction between benzyl bromide and sulfhydryl groups to remove pathogenic bacteria for sepsis treatment is proposed. This strategy retains the phage's host specificity while possessing AIE-PS characteristics with a fluorescence imaging function and reactive oxygen species (ROS) for detecting and sterilizing bacteria. This synergetic strategy combining phage cocktail therapy and photodynamic therapy (PDT) shows a strong "1 + 1 > 2" bactericidal efficacy and superior performance in sepsis mouse models with good biocompatibility. Furthermore, the strategy can quickly diagnose blood infections of clinical blood samples. This simple and accurate strategy provides a promising therapeutic platform for rapid pathogen detection and point-of-care diagnosis. Moreover, it presents a new method for expanding the library of antibacterial drugs to develop new strain identification and improve infectious disease treatment, thereby demonstrating strong translational potential.

Cloning, characterization and functional analysis of NtMYB306a gene reveals its role in wax alkane biosynthesis of tobacco trichomes and stress tolerance.

Trichomes are specialized hair-like organs found on epidermal cells of many terrestrial plants, which protect plant from excessive transpiration and numerous abiotic and biotic stresses. However, the genetic basis and underlying mechanisms are largely unknown in Nicotiana tabacum (common tobacco), an established model system for genetic engineering and plant breeding. In present study, we identified, cloned and characterized an unknown function transcription factor NtMYB306a from tobacco cultivar K326 trichomes. Results obtained from sequence phylogenetic tree analysis showed that NtMYB306a-encoded protein belonged to S1 subgroup of the plants' R2R3-MYB transcription factors (TFs). Observation of the green fluorescent signals from NtMYB306a-GFP fusion protein construct exhibited that NtMYB306a was localized in nucleus. In yeast transactivation assays, the transformed yeast containing pGBKT7-NtMYB306a construct was able to grow on SD/-Trp-Ade+X-α-gal selection media, signifying that NtMYB306a exhibits transcriptional activation activity. Results from qRT-PCR, in-situ hybridization and GUS staining of transgenic tobacco plants revealed that NtMYB306a is primarily expressed in tobacco trichomes, especially tall glandular trichomes (TGTs) and short glandular trichomes (SGTs). RNA sequencing (RNA-seq) and qRT-PCR analysis of the NtMYB306a-overexpressing transgenic tobacco line revealed that NtMYB306a activated the expression of a set of key target genes which were associated with wax alkane biosynthesis. Gas Chromatography-Mass Spectrometry (GC-MS) exhibited that the total alkane contents and the contents of n-C28, n-C29, n-C31, and ai-C31 alkanes in leaf exudates of NtMYB306a-OE lines (OE-3, OE-13, and OE-20) were significantly greater when compared to WT. Besides, the promoter region of NtMYB306a contained numerous stress-responsive cis-acting elements, and their differential expression towards salicylic acid and cold stress treatments reflected their roles in signal transduction and cold-stress tolerance. Together, these results suggest that NtMYB306a is necessarily a positive regulator of alkane metabolism in tobacco trichomes that does not affect the number and morphology of tobacco trichomes, and that it can be used as a candidate gene for improving stress resistance and the quality of tobacco.

Long Intergenic Non-Coding 00162 as Diagnostic Biomarker for Early-Stage Pancreatic Cancer.

OBJECTIVE: Pancreatic cancer (PC) is the fourth leading cause of cancer death due to insufficient diagnostic methods in early stage of PC. Growing evidence has shown that long intergenic non-coding RNAs (LINCRNAs) is a biomarker of the early-stage of PC. However, the expression level and diagnostic value of LINC00162 remains unclear. METHODS: LINC00162 expression was detected in peripheral blood samples from 155 subjects (52 healthy controls, 52 benign pancreatic disease (BPD) persons and 51 PC patients) by quantitative reverse transcription real-time polymerase chain reaction. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic value of LINC00162, carcinoembryonic antigen (CEA) and cancer antigen 199 (CA199). RESULTS: Our data indicated that the LINC00162 expression was upregulated in PC patients compared with healthy controls and BPD (all P<0.001). Furthermore, PC patients with advanced pathological grades, positive lymph node metastasis and positive distant metastasis showed higher LINC00162 levels (all P<0.001). In addition, the area under the ROC curve (AUC) found that the LINC00162 had higher diagnostic ability than CEA and CA199 in distinguishing the early-stage PC patients (AUC: LINC00162 versus(vs) CEA vs CA199=0.932 vs 0.669 vs 0.725). CONCLUSION: In summary, the LINC00162 may be a noninvasive and efficient marker for identifying patients with the early-stage PC. Further validation studies with a large number of patients and long-term follow-up patients are needed to confirm the potential diagnostic value and clinical utility of LINC00162 in patients with PC.

EST12 regulates Myc expression and enhances anti-mycobacterial inflammatory response via RACK1-JNK-AP1-Myc immune pathway.

c-Myc (Myc) is a well-known transcription factor that regulates many essential cellular processes. Myc has been implicated in regulating anti-mycobacterial responses. However, its precise mechanism in modulating mycobacterial immunity remains elusive. Here, we found that a secreted Rv1579c (early secreted target with molecular weight 12 kDa, named EST12) protein, encoded by virulent Mycobacterium tuberculosis (M.tb) H37Rv region of deletion (RD)3, induces early expression and late degradation of Myc protein. Interestingly, EST12-induced Myc was further processed by K48 ubiquitin proteasome degradation in E3 ubiquitin ligase FBW7 dependent manner. EST12 protein activates JNK-AP1-Myc signaling pathway, promotes Myc binding to the promoters of IL-6, TNF-α and iNOS, then induces the expression of pro-inflammatory cytokines (IL-6 and TNF-α)/inducible nitric oxide synthase (iNOS)/nitric oxide (NO) to increase mycobacterial clearance in a RACK1 dependent manner, and these effects are impaired by both Myc and JNK inhibitors. Macrophages infected with EST12-deficiency strain (H37RvΔEST12) displayed less production of iNOS, IL-6 and TNF-α. In conclusion, EST12 regulates Myc expression and enhances anti-mycobacterial inflammatory response via RACK1-JNK-AP1-Myc immune pathway. Our finding provides new insights into M.tb-induced immunity through Myc.

Triplex Immunostrip Assay for Rapid Diagnosis of Tobacco Mosaic Virus, Tobacco Vein Banding Mosaic Virus, and Potato Virus Y.

Mixed virus infection has increasingly become a problem in the production of Solanaceae crops in recent years; therefore, a fast and accurate detection method is needed. In this study, a novel triplex immunostrip assay was developed for the simultaneous detection of tobacco mosaic virus (TMV), tobacco vein banding mosaic virus (TVBMV), and potato virus Y (PVY). The limits of detection of this novel immunostrip reached 200 ppb (ng/ml), 1 ppm (µg/ml), and 2 ppm for TMV, PVY, and TVBMV particles, respectively. Importantly, no cross-reactivity was observed among TMV, TVBMV, and PVY or to a nontarget virus. When the assay was applied to suspected virus-infected tobacco, tomato, and potato samples collected from fields in Southwest China, samples of single or mixed virus infection were successfully identified. In conclusion, the triplex immunostrip assay provides a fast and easy to use on-site detection method for field epidemiological studies of TMV, TVBMV, and PVY, and for managing diseases that are caused by them.

Host MKRN1-Mediated Mycobacterial PPE Protein Ubiquitination Suppresses Innate Immune Response.

Mycobacterium tuberculosis (Mtb), as an important intracellular pathogen, can invade and survive in macrophages and is capable of escaping the clearance of immune system. Despite decades of research efforts, the precise mechanism of immune escape and the virulence factors encoded by Mtb involved remain to be explored. Mtb-specific genomic regions of deletion (RD)-encoded proteins and PE/PPE family proteins have been implicated in immune evasion. Here, we screened more than forty RD-encoded proteins which might be involved in facilitating bacterial survival in macrophages, and found that a Mtb PPE68/Rv3873 protein, encoded by Mtb-RD1, is essential for efficient Mtb intracellular survival in macrophages. In terms of mechanism, we found that the ubiquitin ligase (E3) Makorin Ring Finger Protein 1 (MKRN1) of macrophage interacted with PPE68 and promoted the attachment of lysine (K)-63-linked ubiquitin chains to the K166 site of PPE68. K63-ubiquitination of PPE68 further bound src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP1) to suppress K63-linked polyubiquitin chains of tumor necrosis factor receptor-associated factor 6 (TRAF6), and then remarkably suppressed TRAF6-driven NF-κB and AP-1 signaling and TNF-α, IL-6 and NO production. We demonstrate that the K63-linked ubiquitination of PPE68 by MKRN1 contributed to the PPE68-mediated mycobacterial immune escape. Our finding identifies a previously unrecognized mechanism by which host MKRN1-mediated-ubiquitination of mycobacterial PPE protein suppresses innate immune responses. Disturbing the interaction between host MKRN1 ubiquitin system and mycobacterial PPE protein might be a potential therapeutic target for tuberculosis.

Lnc-EST12, which is negatively regulated by mycobacterial EST12, suppresses antimycobacterial innate immunity through its interaction with FUBP3.

Long noncoding RNAs (lncRNAs) have been implicated in the pathogenesis of intracellular pathogens. However, the role and mechanism of the important lncRNAs in Mycobacterium tuberculosis (M.tb) infection remain largely unexplored. Recently, we found that a secreted M.tb Rv1579c (an early secreted target with a molecular weight of 12 kDa, named EST12) protein activates NLRP3-gasdermin D (GSDMD)-mediated pyroptosis and plays a pivotal role in M.tb-induced immunity. In the present study, M.tb and the EST12 protein negatively regulated the expression of a key lncRNA (named lnc-EST12) in mouse macrophages by activating the JAK2-STAT5a signaling pathway. Lnc-EST12, with a size of 1583 bp, is mainly expressed in immune-related organs (liver, lung and spleen). Lnc-EST12 not only reduces the expression of the proinflammatory cytokines IL-1ß, IL-6, and CCL5/8 but also suppresses the NLRP3 inflammasome and GSDMD pyroptosis-IL-1ß immune pathway through its interaction with the transcription factor far upstream element-binding protein 3 (FUBP3). The KH3 and KH4 domains of FUBP3 are the critical sites for binding to lnc-EST12. Deficiency of mouse lnc-EST12 or FUBP3 in macrophages increased M.tb clearance and inflammation in mouse macrophages or mice. In conclusion, we report a new immunoregulatory mechanism in which mouse lnc-EST12 negatively regulates anti-M.tb innate immunity through FUBP3.