Regulation of PKR-dependent RNA translation inhibition by TRIM21 upon virus infection or other stress.

The host always employs various ways to defend against viral infection and spread. However, viruses have evolved their own effective strategies, such as inhibition of RNA translation of the antiviral effectors, to destroy the host's defense barriers. Protein synthesis, commonly controlled by the α-subunit of eukaryotic translation initiation factor 2 (eIF2α), is a basic cellular biological process among all species. In response to viral infection, in addition to inducing the transcription of antiviral cytokines by innate immunity, infected cells also inhibit the RNA translation of antiviral factors by activating the protein kinase R (PKR)-eIF2α signaling pathway. Regulation of innate immunity has been well studied; however, regulation of the PKR-eIF2α signaling pathway remains unclear. In this study, we found that the E3 ligase TRIM21 negatively regulates the PKR-eIF2α signaling pathway. Mechanistically, TRIM21 interacts with the PKR phosphatase PP1α and promotes K6-linked polyubiquitination of PP1α. Ubiquitinated PP1α augments its interaction with PKR, causing PKR dephosphorylation and subsequent translational inhibition release. Furthermore, TRIM21 can constitutively restrict viral infection by reversing PKR-dependent translational inhibition of various previously known and unknown antiviral factors. Our study highlights a previously undiscovered role of TRIM21 in regulating translation, which will provide new insights into the host antiviral response and novel targets for the treatment of translation-associated diseases in the clinic.

3ß-hydroxysteroid-Δ24 reductase dampens anti-viral innate immune responses by targeting K27 ubiquitination of MAVS and STING.

IMPORTANCE: The precise regulation of the innate immune response is essential for the maintenance of homeostasis. MAVS and STING play key roles in immune signaling pathways activated by RNA and DNA viruses, respectively. Here, we showed that DHCR24 impaired the antiviral response by targeting MAVS and STING. Notably, DHCR24 interacts with MAVS and STING and inhibits TRIM21-triggered K27-linked ubiquitination of MAVS and AMFR-triggered K27-linked ubiquitination of STING, restraining the activation of MAVS and STING, respectively. Together, this study elucidates how one cholesterol key enzyme orchestrates two antiviral signal transduction pathways.

Activation of AIM2 by hepatitis B virus results in antiviral immunity that suppresses hepatitis C virus during coinfection.

IMPORTANCE: Clinical data suggest that Hepatitis C virus (HCV) levels are generally lower in Hepatitis B virus (HBV) co-infected patients, but the mechanism is unknown. Here, we show that HBV, but not HCV, activated absent in melanoma-2. This in turn results in inflammasome-mediated cleavage of pro-IL-18, leading to an innate immune activation cascade that results in increased interferon-γ, suppressing both viruses.

New methods for resolution of hydroxychloroquine by forming diastereomeric salt and adding chiral mobile phase agent on RP-HPLC.

Hydroxychloroquine (HCQ), 2-([4-([7-Chloro-4-quinolyl]amino)pentyl]ethylamino)ethanol, exhibited significant biological activity, while its side effects cannot be overlooked. The RP-HPLC enantio-separation was investigated for cost-effective and convenient optical purity analysis of HCQ. The thermodynamic resolution of Rac-HCQ, driven by enthalpy and entropy, was achieved on the C18 column using Carboxymethyl-ß-cyclodextrin (CM-ß-CD) as the chiral mobile phase agent (CMPA). The effects of CCM-ß-CD, pH, and triethylamine (TEA) V% on the enantio-separation process were explored. Under the optimum conditions at 24°C, the retention times for the two enantiomers were t R 1 = 29.39 min $$ {t}_{R1}=29.39\ \min $$ and t R 2 = 32.42 min $$ {t}_{R2}=32.42\ \min $$ , resulting in R s = 1.87 $$ {R}_s=1.87 $$ . The resolution via diastereomeric salt formation of Rac-HCQ was developed to obtain the active pharmaceutical ingredient of single enantiomer S-HCQ. Di-p-Anisoyl-L-Tartaric Acid (L-DATA) was proved effective as the resolution agent for Rac-HCQ. Surprisingly, it was found that refluxing time was a key fact affecting the resolution efficiency, which meant the kinetic dominate during the process of the resolution. Four factors-solvent volume, refluxing time, filtration temperature, and molar ratio-were optimized using the single-factor method and the response surface method. Two cubic models were established, and the reliability was subsequently verified. Under the optimal conditions, the less soluble salt of 2L-DATA:S-HCQ was obtained with a yield of 96.9% and optical purity of 63.0%. The optical purity of this less soluble salt increases to 99.0% with a yield of 74.2% after three rounds recrystallization.

First report of Neopestalotiopsis clavispora Causing guava scab in China.

Psidium guajava L. is widely cultivated in southern China. In May 2021, guava scab on cv. Zhenzhu was observed in Zhanjiang (21.18° N, 110.21° E), Guangdong province, China. Guava scab was corky with ovoid or round lesions on the surfaces of green fruits. Gradually the lesions sunk. Disease incidence was estimated as 85% in 500 investigated plants in about 50 ha. Twenty diseased fruits were collected from twenty trees in the field. From each fruit the margin of the diseased tissues was cut into 2 mm × 2 mm pieces; surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, successively; and rinsed thrice with sterile water. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. Thirty-four isolates were obtained. Single-spore isolation method (Liu et al. 2021) was used to recover pure cultures of three isolates (PGNC-1, PGNC-2, and PGNC-3) . The colonies were initially white with cottony aerial mycelium at 7 days on PDA. Then, these colonies form black acervular conidiomata at 10 days. Conidia were clavate to fusiform, four-septate, straight or slightly curved, and measured 15.8 to 21.2 µm × 4.5 to 6.5 µm (n = 40). The three median cells were versicolored, whereas the basal and apical cells were hyaline. Conidia had a single basal appendage (4.5 to 5.5 µm long; n = 40) and three apical appendages (19.2 to 24.5 µm long; n = 40). The morphological characteristics of the isolates were consistent with the description of Neopestalotiopsis clavispora (Maharachchikumbura et al. 2012). Molecular identification was performed using PCR method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012). Sequences were generated from the isolates using primers for the rDNA ITS (ITS1/ITS4), TEF1-α (EF1-728F/EF1-986R), and ß-tubulin (T1/ßt2b) loci (Maharachchikumbura et al. 2012). The sequences of the isolates were submitted to GenBank (ITS, OQ996557 to OQ996559; TEF, OR101037 to OR101039; ß-tubulin, OR100971 to OR100973). The sequences of the isolates were 100% identical to the type strain MFLUCC12-0281 (accession nos. JX398979, JX399014, and JX399045) through BLAST analysis. The isolates clustered with N. clavispora (MFLUCC12-0280 and MFLUCC12-0281). N. clavispora and Pestalotiopsis clavispora are synonyms. The pathogenicity was tested in vivo. Plants (cv. Zhenzhu) were grown ( 3 years old) in a quarantine orchard at 25 â„ƒ to 32 â„ƒ with 60 to 80% relative humidity in May 2022. Disease-free green fruits were inoculated. Sterile cotton balls were immersed in the spore suspension (1 × 105 per mL) and sterile distilled water (control) for about 15 s before they were fixed on the wounded fruits with transparent tape. Five fruits on one plant per isolate were inoculated. Five fruits on one plant severed as control. The test was performed thrice. Disease symptoms were found on the inoculated fruits after 20 days, whereas the controls remained healthy. The pathogen was re-isolated from infected fruits and was phenotypically identical to the original isolates thus fulfilling Koch's postulates. Neopestalotiopsis or Pestalotiopsis spp. were reported to be the causal agents of guava scab in Colombia and in Hawaii (Keith et al. 2006; Solarte et al. 2018). N. clavispora has been reported to cause disease in a broad range of hosts (Ge et al. 2009; Chen et al. 2018), but not in guava. This is the first report of N. clavispora causing guava scab in China. There would be no harvest if this disease is left unmanaged.

Programmable Proteolysis-Activated Transcription for Highly Sensitive Ratiometric Electrochemical Detection of Viral Protease.

Viral proteases play a crucial role in viral infection and are regarded as promising targets for antiviral drug development. Consequently, biosensing methods that target viral proteases have contributed to the study of virus-related diseases. This work presents a ratiometric electrochemical sensor that enables highly sensitive detection of viral proteases through the integration of target proteolysis-activated in vitro transcription and the DNA-functionalized electrochemical interface. In particular, each viral protease-mediated proteolysis triggers the transcription of multiple RNA outputs, leading to amplified ratiometric signals on the electrochemical interface. Using the NS3/4A protease of the hepatitis C virus as a model, this method achieves robust and specific NS3/4A protease sensing with sub-femtomolar sensitivity. The feasibility of this sensor was demonstrated by monitoring NS3/4A protease activities in virus-infected cell samples with varying viral loads and post-infection times. This study provides a new approach to analyzing viral proteases and holds the potential for developing direct-acting antivirals and novel therapies for viral infections.

The Role of REC8 in the Innate Immune Response to Viral Infection.

REC8 meiotic recombination protein (REC8) is a member of structural maintenance of chromosome (SMC) protein partners, which play an important role in meiosis, antitumor activity, and sperm formation. As the adaptor proteins of RIG-I-like receptor (RLR) signaling and cyclic GMP-AMP synthase (cGAS)-DNA signaling, the activity and stability of MAVS (mitochondrial antiviral signaling protein; also known as VISA, Cardif, and IPS-1) and STING (stimulator of interferon genes; also known as MITA) are critical for innate immunity. Here, we report that REC8 interacts with MAVS and STING and inhibits their ubiquitination and subsequent degradation, thereby promoting innate antiviral signaling. REC8 is upregulated through the JAK-STAT signaling pathway during viral infection. Knockdown of REC8 impairs the innate immune responses against vesicular stomatitis virus (VSV), Newcastle disease virus (NDV), and herpes simplex virus (HSV). Mechanistically, during infection with viruses, the SUMOylated REC8 is transferred from the nucleus to the cytoplasm and then interacts with MAVS and STING to inhibit their K48-linked ubiquitination triggered by RNF5. Moreover, REC8 promotes the recruitment of TBK1 to MAVS and STING. Thus, REC8 functions as a positive modulator of innate immunity. Our work highlights a previously undocumented role of meiosis-associated protein REC8 in regulating innate immunity. IMPORTANCE The innate immune response is crucial for the host to resist the invasion of viruses and other pathogens. STING and MAVS play a critical role in the innate immune response to DNA and RNA viral infection, respectively. In this study, REC8 promoted the innate immune response by targeting STING and MAVS. Notably, REC8 interacts with MAVS and STING in the cytoplasm and inhibits K48-linked ubiquitination of MAVS and STING triggered by RNF5, stabilizing MAVS and STING protein to promote innate immunity and gradually inhibiting viral infection. Our study provides a new insight for the study of antiviral innate immunity.

Heat Shock-Binding Protein 21 Regulates the Innate Immune Response to Viral Infection.

The induction of interferons (IFNs) plays an important role in the elimination of invading pathogens. Heat shock binding protein 21 (HBP21), first known as a molecular chaperone of HSP70, is involved in tumor development. Heat shock binding proteins have been shown to regulate diverse biological processes, such as cell cycle, kinetochore localization, transcription, and cilium formation. Their role in antimicrobial immunity remains unknown. Here, we found that HBP21 drives a positive feedback loop to promote IRF3-mediated IFN production triggered by viral infection. HBP21 deficiency significantly impaired the virus-induced production of IFN and resulted in greater susceptibility to viral infection both in vitro and in vivo. Mechanistically, HBP21 interacted with IRF3 and promoted the formation of a TBK1-IRF3 complex. Moreover, HBP21 abolished the interaction between PP2A and IRF3 to repress the dephosphorylation of IRF3. Analysis of HBP21 protein structure further confirmed that HBP21 promotes the activation of IRF3 by depressing the dephosphorylation of IRF3 by PP2A. Further study demonstrated that virus-induced phosphorylation of Ser85 and Ser153 of HBP21 itself is important for the phosphorylation and dimerization of IRF3. Our study identifies HBP21 as a new positive regulator of innate antiviral response, which adds novel insight into activation of IRF3 controlled by multiple networks that specify behavior of tumors and immunity. IMPORTANCE The innate immune system is the first-line host defense against microbial pathogen invasion. The physiological functions of molecular chaperones, involving cell differentiation, migration, proliferation and inflammation, have been intensively studied. HBP21 as a molecular chaperone is critical for tumor development. Tumor is related to immunity. Whether HBP21 regulates immunity remains unknown. Here, we found that HBP21 promotes innate immunity response by dual regulation of IRF3. HBP21 interacts with IRF3 and promotes the formation of a TBK1-IRF3 complex. Moreover, HBP21 disturbs the interaction between PP2A and IRF3 to depress the dephosphorylation of IRF3. Analysis of HBP21 protein structure confirms that HBP21 promotes the activation of IRF3 by blocking the dephosphorylation of IRF3 by PP2A. Interestingly, virus-induced Ser85 and Ser153 phosphorylation of HBP21 is important for IRF3 activation. Our findings add to the known novel immunological functions of molecular chaperones and provide new insights into the regulation of innate immunity.

Vsig4+ resident single-Kupffer cells improve hepatic inflammation and fibrosis in NASH.

BACKGROUND: The role of macrophages in the pathogenesis of nonalcoholic steatohepatitis (NASH) is complex and unclear. METHODS: Single-cell RNA sequencing was performed on nonparenchymal cells isolated from NASH and control mice. The expression of Vsig4+ macrophages was verified by qPCR, flow cytometry and immunohistochemistry. Primary hepatic macrophages were cocultured with primary hepatocytes or hepatic stellate cells (LX2) cells by Transwell to detect immunofluorescence and oil red O staining. RESULTS: Two main single macrophage subsets were identified that exhibited a significant change in cell percentage when NASH occurred: resident Kupffer cells (KCs; Cluster 2) and lipid-associated macrophages (LAMs; Cluster 13). Nearly 82% of resident single KCs in Cluster 2 specifically expressed Cd163, and an inhibited subgroup of Cd163+ resident single-KCs was suggested to be protective against NASH. Similar to Cd163, Vsig4 was both enriched in and specific to Cluster 2. The percentage of Vsig4+-KCs was significantly decreased in NASH in vivo and in vitro. Hepatocytes and hepatic stellate cells produced less lipid droplet accumulation, proinflammatory protein (TNF-α) and profibrotic protein (α-SMA) in response to coculture with Vsig4+-KCs than in those cocultured with lipotoxic KCs. CONCLUSIONS: A subgroup of Vsig4+ resident single-KCs was shown to improve hepatic inflammation and fibrosis in NASH.

First Report of Mucor irregularis Causing Flower Rot on Selenicereus undatus in China.

Dragon fruit (Selenicereus undatus (Haw.) D.R.Hunt is a famous tropical fruit (Korotkova et al. 2017). In May 2021, a flower rot disease was found on Dragon fruit in a field (21˚19'42''N, 110˚28'32''E), Zhanjiang, Guangdong Province, China. The incidence rate was approximately 30% (n=500 investigated plants from about 30 hectares). Flower rot was evident, and was light brown, watery, soft, and covered with white mycelia. The pathogen could continue to infect the fruit during the fruit ripening stage with about 20% rot rate. Ten samples of symptomatic flowers were collected in the field. Margins of the diseased tissue were cut into 2 mm × 2 mm pieces. The surfaces were disinfected with 75% ethanol for 30 s and 2% sodium hypochlorite for 60 s. Pure cultures were obtained by transferring hyphal tips to new PDA plates. Three representative isolates (HUM-1,HUM-2, and HUM-3) by single-spore isolation were randomly selected for further study. Colonies on PDA were circular with massive aerial hyphae, white to ochraceous in color. Nonseptate hyphae were hyaline. Sporangiophores arose from hyphae. Sporangiospores were hyaline, smooth-walled, mostly subspherical to ellipsoidal, and measured 3.15 to 6.55 µm × 1.35 to 2.85 µm (n =50). Morphological characteristics of isolates were consistent with the description of Mucor irregularis (Lima et al. 2018). Molecular identification was done using the colony PCR method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) used to amplify the internal transcribed spacer (ITS) region and large subunit (LSU) with ITS1/ITS4 and LR0R1/LR5 (Vilgalys et al. 1990). The amplicons were sequenced and the sequences were deposited in GenBank with accession numbers ITS, OL376751-OL376753, and LSU, OM672239-OM672241. BLAST analysis of these sequences revealed a 100% identity with M. irregularis in GenBank. The sequences were also concatenated for phylogenetic analysis by the maximum likelihood method. The isolates clustered with M. irregularis (the type strain CBS 103.93).The pathogenicity was tested through in vivo experiments. Nine healthy flowers of Dragon fruit were inoculated with 3-day-old mycelial plugs (5 × 5 mm) of isolates, while another five healthy flowers were treated with PDA plugs (controls). Those plugs were embedded inside the calyxes, and each flower was inoculated with one plug in one calyx. Besides, the inoculated and control flowers (n = 5) were sprayed with a spore suspension (1 × 105 per mL) of the three isolates individually and sterile distilled water, respectively, until run-off (Feng and Li. 2019). The plants were grown in pots in a greenhouse at 28°C, with relative humility approximately 80%. The test was repeated three times. After 3 days of incubation, rot symptoms developed on the inoculated flowers, which were similar to those observed on the naturally samples in the field. The control flowers remained healthy. The fungus was reisolated from the inoculated flowers and confirmed as M. irregularis by morphology and ITS analysis. M. irregularis was reported as a pathogen causing human skin diseases and post-harvest diseases of crop (Álvarez et al. 2011; Lima et al. 2018; Wang et al. 2022). This is the first report of M. irregularis causing flower rot of Dragon fruit and reduce yield in China. This research can provide a theoretical basis for the fruit industry to maintain yield.

Construction of Asymmetrical Dual Jahn-Teller Sites for Photocatalytic CO2 Reduction.

Photocatalytic CO2 reduction (PCR) expresses great attraction to convert useless greenhouse gas into valuable chemical feedstock. However, the weak interactions between catalytic sites and PCR intermediates constrains the PCR activity and selectivity. Herein, we proposed a new strategy to match the intermediates due to the maximum orbital overlap of catalytic sites and C1 intermediates by establishing dual Jahn-Teller (J-T) sites, in which, the strongly asymmetric J-T sites can break the nonpolar CO2 molecules and self-adapt the different structure of C1 intermediates. Taking cobalt carbonate hydroxide as an example, the weakly symmetric dual cobalt (Co2 ) dual J-T sites, weakly asymmetric Fe&Co sites and strongly asymmetric Cu&Co sites were assembled. After illumination, the interaction between dual J-T sites and the CO2 molecules enhances J-T distortion, which further modulates the PCR activity and selectivity. As a result, the Cu&Co sites exhibited CO yield of 8137.9 µmol g-1 , about 2.3-fold and 4.2-fold higher than that of the Fe&Co and Co2 sites within 5-hour photoreaction, respectively. In addition, the selectivity achieved as high as 92.62 % than Fe&Co (88.67 %) and Co2 sites (55.33 %). This work provides a novel design concept for the construction of dual J-T sites to regulate the catalytic activity and selectivity.

CircRNA608-microRNA222-PINK1 axis regulates the mitophagy of hepatic stellate cells in NASH related fibrosis.

BACKGROUND: Increasing evidences have confirmed the relationship between mitophagy and nonalcoholic steatohepatitis (NASH). The exact mechanism of upstream circular RNAs (circRNAs) regulating PTEN-induced putative kinase 1 (PINK1) mediated mitophagy and its contribution to NASH-related liver fibrosis was explored in our study. METHODS: Primary hepatic stellate cells (PHSCs) from C57BL/6 mice transfected with small interfering RNAs against PINK1 (si-PINK1) and negative control (si-NC) were prepared to perform circRNA sequence. Differentially expressed circRNAs, bioinformatic analysis and predicting software were performed to select axis of circ608/miR-222/PINK1. The expressions of circ608/miR-222/PINK1 were verified by RT-qPCR. The mitochondrial function was evaluated by immunofluorescence staining of COX4 and LC3B. RESULTS: PINK1-mediated mitophagy was inhibited in NASH-related liver fibrosis mice. CircRNA sequence revealed there were 37 DE-circRNAs between si-PINK1 PHSCs and si-NC PHSCs. Bioinformatic analysis showed these DE-circRNAs were related to enriched signaling pathways (such as Wnt, Rap1, mTOR, Hippo) regulating liver fibrosis and mitophagy. Circ608 was significantly down-regulated in lipotoxic HSCs and in livers of NASH-related liver fibrosis mice. MiR222 was identified to be the target miRNA of circ608 and was negatively regulated by circ608 in lipotoxic HSCs. MiR222 also had a binding site with PINK1 and could negatively regulate PINK1. So, the axis of circ608-miR222-PINK1 was proved to participate in NASH-related liver fibrosis by regulating mitophagy. These results illustrated that circ608 might promote PINK1-mediated mitophagy though inhibiting miR222 in lipotoxic HSCs. CONCLUSION: Circ608 could promote PINK1-mediated mitophagy of HSCs though inhibiting miR222 in NASH-related liver fibrosis.

The oncogenic miR-27a/BTG2 axis promotes obesity-associated hepatocellular carcinoma by mediating mitochondrial dysfunction.

Obesity is closely related to the initiation and development of hepatocellular carcinoma (HCC). The regulatory mechanism of obesity-associated HCC remains unclear. HepG2 cells treated with palmitic acid (PA) and diethylnitrosamine (DEN)-induced HCC mice fed a high-fat diet (HFD) were established. The expression of miR-27a and B-cell translocation gene 2 (BTG2) mRNA and protein were detected via qPCR and western blotting. Prediction software and luciferase assays were employed to verify the miR-27a/BTG2 axis. The biological effects of HepG2 cells were evaluated with ORO staining, MTT assays, Transwell assays, Mito-Timer, and Mito-SOX staining. Significantly upregulated miR-27a and downregulated BTG2 mRNA and protein were observed in HepG2 cells and liver tissues of HCC mice. Overexpressing miR-27a (mi-miR-27a) markedly promoted cellular lipid accumulation, proliferation, and invasion, accompanied by aggravated mitochondrial dysfunction (increased fading and ROS products of mitochondria) in HepG2 cells. Additionally, these effects were further reinforced in HepG2 cells treated with mi-miR-27a and PA. BTG2 was identified as a direct target and was negatively regulated by miR-27a. Similarly, BTG2 knockdown (sh-BTG2) had effects identical to those of mi-miR-27a on HepG2 cells. Additionally, PA evidently enhanced these effects of sh-BTG2 in HepG2 cells. Moreover, BTG2 overexpression effectively reversed the effects of miR-27a, including lipotropic and oncogenic effects, and simultaneously promoted mitochondrial imbalance in HepG2 cells. Thus, obesity-associated miR-27a acts as an oncogene to promote lipid accumulation, proliferation, and invasion by negatively regulating BTG2-mediated mitochondrial dysfunction in HCC.

First report of Neopestalotiopsis clavispora Causing Leaf Spots on Garcinia mangostana in China.

Garcinia mangostana L. is a famous tropical fruit in Asia. In April 2021, a leaf disease on G. mangostana cv. Huazhu was observed in Zhanjiang (21.17° N, 110.18° E), Guangdong province, China. Symptoms was on new leaves of 2 year old plants. The spots were circular to irregular, gray in the center, and brown on the lesion margin. The disease incidence was estimated 25% (n = 500 investigated plants from about 50-ha). Twenty diseased leaves were collected from the orchard. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces; surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively; and rinsed thrice with sterile water. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. Twenty-eight isolates were obtained (isolation frequency = 28/4×20 = 35%). Single-spore isolation method was used to recover pure cultures for three isolates (GMN-1, GMN-2, and GMN-3) (Liu et al. 2021). The colonies were initially white with cottony aerial mycelium at 7 days on PDA. Then, they developed black acervular conidiomata at 10 days. Conidia were clavate to fusiform, four-septate, straight or slightly curved, and measured 16.5 to 21.4 µm long (average 19.5 µm; n = 40) × 4.5 to 6.5 µm wide (average 5.2 µm; n = 40). The three median cells were versicolored, whereas the basal and apical cells were hyaline. Conidia had a single basal appendage (4.5 to 5.5 µm long; n = 40) and three apical appendages (19.2 to 24.5 µm long; n = 40). The morphological characteristics of the isolates are comparable with those of the genus Neopestalotiopsis (Sajeewa et al. 2012). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012). Sequences were generated from the isolates using primers for the rDNA ITS (ITS1/ITS4), TEF1-α (EF1-728F/EF1-986R), and ß-tubulin (T1/ßt2b) loci (Sajeewa et al. 2012). The sequences of the isolates were submitted to GenBank (ITS, MZ026535-MZ026537; TEF, MZ032203-MZ032205; ß-tubulin, MZ032206-MZ032208). The sequences of the isolates were 100% identical to the type strain MFLUCC12-0281 (accession nos. JX398979, JX399014, and JX399045) through BLAST analysis. The isolates clustered with N. clavispora (MFLUCC12-0280 and MFLUCC12-0281). The pathogenicity was tested in vivo. Individual plants (cv. Huazhu) were grown (n = 2, 1-1.5 year old) in a greenhouse at 24 â„ƒ-30 â„ƒ with 80% relative humidity. Wounded leaflets were inoculated with 5-mm-diameter mycelial plugs or agar plugs (as control). Besides, sterile cotton balls were immersed in the spore suspension (1 × 105 per mL) and sterile distilled water (control) for about 15 s before they were fixed on the leaves for 3 days. One plant employed for each isolate with nine leaves. The test was performed thrice. Disease symptoms were found on the leaflets after 10 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and phenotypically identical to the original isolates to fulfill Koch's postulates. Neopestalotiopsis clavispora and Pestalotiopsis clavispora are synonyms. The fungus appeared to have a wide host range and distribution including in Thailand, Malaysia, North Queensland, and Australia (Sajeewa et al. 2012;Shahriar et al. 2022). Thus, this is the first report of N. clavispora causing leaf spot on G. mangostana in China. This finding will help improve management strategies against the leaf spots on G. mangostana in China.

Development of Near-Infrared Nucleic Acid Mimics of Fluorescent Proteins for In Vivo Imaging of Viral RNA with Turn-On Fluorescence.

GFP-like fluorescent proteins and their molecular mimics have revolutionized bioimaging research, but their emissions are largely limited in the visible to far-red region, hampering the in vivo applications in intact animals. Herein, we structurally modulate GFP-like chromophores using a donor-acceptor-acceptor (D-A-A') molecular configuration to discover a set of novel fluorogenic derivatives with infrared-shifted spectra. These chromophores can be fluorescently elicited by their specific interaction with G-quadruplex (G4), a unique noncanonical nucleic acid secondary structure, via inhibition of the chromophores' twisted-intramolecular charge transfer. This feature allows us to create, for the first time, FP mimics with tunable emission in the near-infrared (NIR) region (Emmax = 664-705 nm), namely, infrared G-quadruplex mimics of FPs (igMFP). Compared with their FP counterparts, igMFPs exhibit remarkably higher quantum yields, larger Stokes shift, and better photostability. In a proof-of-concept application using pathogen-related G4s as the target, we exploited igMFPs to directly visualize native hepatitis C virus (HCV) RNA genome in living cells via their in situ formation by the chromophore-bound viral G4 structure in the HCV core gene. Furthermore, igMFPs are capable of high contrast HCV RNA imaging in living mice bearing a HCV RNA-presenting mini-organ, providing the first application of FP mimics in whole-animal imaging.

IRF1 Promotes the Innate Immune Response to Viral Infection by Enhancing the Activation of IRF3.

Innate immunity is an essential way for host cells to resist viral infection through the production of interferons (IFNs) and proinflammatory cytokines. Interferon regulatory factor 3 (IRF3) plays a critical role in the innate immune response to viral infection. However, the role of IRF1 in innate immunity remains largely unknown. In this study, we found that IRF1 is upregulated through the IFN/JAK/STAT signaling pathway upon viral infection. The silencing of IRF1 attenuates the innate immune response to viral infection. IRF1 interacts with IRF3 and augments the activation of IRF3 by blocking the interaction between IRF3 and protein phosphatase 2A (PP2A). The DNA binding domain (DBD) of IRF1 is the key functional domain for its interaction with IRF3. Overall, our study reveals a novel mechanism by which IRF1 promotes the innate immune response to viral infection by enhancing the activation of IRF3, thereby inhibiting viral infection.IMPORTANCE The activation of innate immunity is essential for host cells to restrict the spread of invading viruses and other pathogens. IRF3 plays a critical role in the innate immune response to RNA viral infection. However, whether IRF1 plays a role in innate immunity is unclear. In this study, we demonstrated that IRF1 promotes the innate immune response to viral infection. IRF1 is induced by viral infection. Notably, IRF1 targets and augments the phosphorylation of IRF3 by blocking the interaction between IRF3 and PP2A, leading to the upregulation of innate immunity. Collectively, the results of our study provide new insight into the regulatory mechanism of IFN signaling and uncover the role of IRF1 in the positive regulation of the innate immune response to viral infection.

Lessons learned from upper gastrointestinal endoscopy in asymptomatic Chinese.

BACKGROUND: The Helicobacter pylori (H. pylori) infection-related diseases, peptic ulcer, and gastric cancer are frequently asymptomatic until the onset of complications. This study aimed to investigate the prevalence of H. pylori, erosive esophagitis, peptic ulcer, and precancerous lesions such as atrophic gastritis, intestinal metaplasia, gastric dysplasia, and upper gastrointestinal (GI) malignancy in asymptomatic Chinese. METHODS: From January to December 2017, a questionnaire was administered to consecutive asymptomatic patients undergoing routine physical examination, which included their first screening esophagogastroduodenoscopy. H. pylori infection was determined by one of positive 13 C urea breath tests or rapid urease test and histology. The presence of H. pylori infection, erosive esophagitis, peptic ulcer, precancerous gastric histology, and upper GI malignancy was analyzed in relation to demographic factors. RESULTS: A total of 1108 subjects (mean age: 48, range 21 to 79, 39.5% men) were included. The findings were: erosive esophagitis 7.8%, active H. pylori infection 44%, peptic ulcer 9.1% (duodenal 5.8%, gastric 2.5% or both 0.8%); 0.5% had gastric cancer. Male, smoking history, and current H. pylori infection were all significantly related to the presence of peptic ulcer. Totally, 1095 patients had gastric histopathology and premalignant gastric lesions were present in 67.4%; atrophic gastritis (67.4%), intestinal metaplasia (27.4%), and gastric dysplasia (0.5%). Age, current and previous H. pylori infection were risk factors significantly associated with precancerous lesions. CONCLUSIONS: Upper GI pathology as a sequelae of H. pylori infection is common in asymptomatic Chinese. These findings support institution of a nationwide test and treat program to eradicate H. pylori in China.

Age is the only predictor for upper gastrointestinal malignancy in Chinese patients with uncomplicated dyspepsia: a prospective investigation of endoscopic findings.

BACKGROUND: Dyspepsia is a common cause of physician visits. If and when endoscopy should be performed depend on the regions and the populations. This study aimed to identify the current risk factors predictive of upper gastrointestinal malignancy or peptic ulcer in China with high prevalence of gastric cancer. METHODS: A questionnaire was conducted among consecutive outpatients undergoing their first esophagogastroduodenoscopy for dyspepsia. Symptoms other than alarm symptoms in this study were defined as uncomplicated dyspepsia. RESULTS: 4310 outpatients (mean age 44, median 42, range 14-86) were included in the final analyses. Significant pathology was found in 13.8% (595/4310) patients including peptic ulcer (12.3%) and upper gastrointestinal malignancy (1.5%). Age, male sex and alarm symptoms were significantly associated with malignancy. The age cut-off identified for upper gastrointestinal malignancy was 56 years among patients with uncomplicated dyspepsia, which was similar to the combined cutoff of age and gender. CONCLUSIONS: Age should be considered as the primary predictor for upper gastrointestinal malignancy in Chinese patients with uncomplicated dyspepsia. 56 could probably be the optimal age to identify those lesions in this population. TRIAL REGISTRATION: Chictr.org (ChiCTR2000040775).

Lighting up the Native Viral RNA Genome with a Fluorogenic Probe for the Live-Cell Visualization of Virus Infection.

RNA viruses represent a major global health threat, and the visualization of their RNA genome in infected cells is essential for virological research and clinical diagnosis. Due to the lack of chemical toolkits for the live-cell imaging of viral RNA genomes, especially native viral genomes without labeling and genetic modification, studies on native virus infection at the single-live-cell level are challenging. Herein, taking hepatitis C virus (HCV) as a representative RNA virus, we propose that the innate noncanonical G-quadruplex (G4) structure of viral RNA can serve as a specific imaging target and report a new benzothiazole-based G4-targeted fluorescence light-up probe, ThT-NE, for the direct visualization of the native RNA genome of HCV in living host cells. We demonstrate the use of the ThT-NE probe for several previously intractable applications, including the sensitive detection of individual virus-infected cells by small-molecule staining, real-time monitoring of the subcellular distribution of the viral RNA genome in live cells, and continuous live-cell tracking of the infection and propagation of clinically isolated native HCV. The fluorogenic-probe-based viral RNA light-up system opens up a promising chemical strategy for cutting-edge live-cell viral analysis, providing a potentially powerful tool for viral biology, medical diagnosis, and drug development.

TRIM21 Promotes Innate Immune Response to RNA Viral Infection through Lys27-Linked Polyubiquitination of MAVS.

Human innate immunity responds to viral infection by activating the production of interferons (IFNs) and proinflammatory cytokines. The mitochondrial adaptor molecule MAVS plays a critical role in innate immune response to viral infection. In this study, we show that TRIM21 (tripartite motif-containing protein 21) interacts with MAVS to positively regulate innate immunity. Under viral infection, TRIM21 is upregulated through the IFN/JAK/STAT signaling pathway. Knockdown of TRIM21 dramatically impairs innate immune response to viral infection. Moreover, TRIM21 interacts with MAVS and catalyzes its K27-linked polyubiquitination, thereby promoting the recruitment of TBK1 to MAVS. Specifically, the PRY-SPRY domain of TRIM21 is the key domain for its interaction with MAVS, while the RING domain of TRIM21 facilitates the polyubiquitination chains of MAVS. In addition, the MAVS-mediated innate immune response is enhanced by both the PRY-SPRY and RING domains of TRIM21. Mutation analyses of all the lysine residues of MAVS further revealed that Lys325 of MAVS is catalyzed by TRIM21 for the K27-linked polyubiquitination. Overall, this study reveals a novel mechanism by which TRIM21 promotes the K27-linked polyubiquitination of MAVS to positively regulate innate immune response, thereby inhibiting viral infection.IMPORTANCE Activation of innate immunity is essential for host cells to restrict the spread of invading viruses and other pathogens. MAVS plays a critical role in innate immune response to RNA viral infection. In this study, we demonstrated that TRIM21 targets MAVS to positively regulate innate immunity. Notably, TRIM21 targets and catalyzes K27-linked polyubiquitination of MAVS and then promotes the recruitment of TBK1 to MAVS, leading to upregulation of innate immunity. Our study outlines a novel mechanism by which the IFN signaling pathway blocks RNA virus to escape immune elimination.