iRhom2 is essential for innate immunity to DNA viruses by mediating trafficking and stability of the adaptor STING.

STING is a central adaptor in the innate immune response to DNA viruses. However, the manner in which STING activity is regulated remains unclear. We identified iRhom2 ('inactive rhomboid protein 2') as a positive regulator of DNA-virus-triggered induction of type I interferons. iRhom2 deficiency markedly impaired DNA-virus- and intracellular-DNA-induced signaling in cells, and iRhom2-deficient mice were more susceptible to lethal herpes simplex virus type 1 (HSV-1) infection. iRhom2 was constitutively associated with STING and acted in two distinct processes to regulate STING activity. iRhom2 recruited the translocon-associated protein TRAPß to the STING complex to facilitate trafficking of STING from the endoplasmic reticulum to perinuclear microsomes. iRhom2 also recruited the deubiquitination enzyme EIF3S5 to maintain the stability of STING through removal of its K48-linked polyubiquitin chains. These results suggest that iRhom2 is essential for STING activity, as it regulates TRAPß-mediated translocation and EIF3S5-mediated deubiquitination of STING.

The Zinc-Finger Protein ZCCHC3 Binds RNA and Facilitates Viral RNA Sensing and Activation of the RIG-I-like Receptors.

Recognition of viral RNA by the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) initiates innate antiviral immune response. How the binding of viral RNA to and activation of the RLRs are regulated remains enigmatic. In this study, we identified ZCCHC3 as a positive regulator of the RLRs including RIG-I and MDA5. ZCCHC3 deficiency markedly inhibited RNA virus-triggered induction of downstream antiviral genes, and ZCCHC3-deficient mice were more susceptible to RNA virus infection. ZCCHC3 was associated with RIG-I and MDA5 and functions in two distinct processes for regulation of RIG-I and MDA5 activities. ZCCHC3 bound to dsRNA and enhanced the binding of RIG-I and MDA5 to dsRNA. ZCCHC3 also recruited the E3 ubiquitin ligase TRIM25 to the RIG-I and MDA5 complexes to facilitate its K63-linked polyubiquitination and activation. Thus, ZCCHC3 is a co-receptor for RIG-I and MDA5, which is critical for RLR-mediated innate immune response to RNA virus.

Topological super-modes engineering with acoustic graphene plasmons.

Acoustic graphene plasmons (AGPs) in a graphene-dielectric-metal structure possess extreme field localization and low loss, which have promising applications in strong photon-matter interaction and integrated photonic devices. Here, we propose two kinds of one-dimensional crystals supporting propagating AGPs with different topological properties, which is confirmed by the Zak phase calculations and the electric field symmetry analysis. Moreover, by combining these two plasmonic crystals to form a superlattice system, the super-modes exist because of the coupling between isolated topological interface states. A flat-like dispersion of super-modes is observed by designing the superlattice. These results should find applications in optical sensing and integrating photonic devices with plasmonic crystals.

Photocatalytic synthesis of azaheterocycle-fused piperidines and pyrrolidines via tandem difunctionalization of unactivated alkenes.

A variety of azaheterocycle-fused piperidines and pyrrolidines bearing CF3 and CHF2 functionalities were obtained using CF3SO2Na and CHF2SO2Na by visible light photocatalysis. This protocol involves a radical cascade cyclization via tandem tri- and difluoromethylation-arylation of pendent unactivated alkenes. Benzimidazole, imidazole, theophylline, purine, and indole serve as applicable anchors, thereby enriching the structural diversity of piperidine and pyrrolidine derivatives. This method features mild, additive-free and transition metal-free conditions.

Ubiquitination of TLR3 by TRIM3 signals its ESCRT-mediated trafficking to the endolysosomes for innate antiviral response.

Trafficking of toll-like receptor 3 (TLR3) from the endoplasmic reticulum (ER) to endolysosomes and its subsequent proteolytic cleavage are required for it to sense viral double-stranded RNA (dsRNA) and trigger antiviral response, yet the underlying mechanisms remain enigmatic. We show that the E3 ubiquitin ligase TRIM3 is mainly located in the Golgi apparatus and transported to the early endosomes upon stimulation with the dsRNA analog poly(I:C). TRIM3 mediates K63-linked polyubiquitination of TLR3 at K831, which is enhanced following poly(I:C) stimulation. The polyubiquitinated TLR3 is recognized and sorted by the ESCRT (endosomal sorting complex required for transport) complexes to endolysosomes. Deficiency of TRIM3 impairs TLR3 trafficking from the Golgi apparatus to endosomes and its subsequent activation. Trim3-/- cells and mice express lower levels of antiviral genes and show lower levels of inflammatory response following poly(I:C) but not lipopolysaccharide (LPS) stimulation. These findings suggest that TRIM3-mediated polyubiquitination of TLR3 represents a feedback-positive regulatory mechanism for TLR3-mediated innate immune and inflammatory responses.

A highly sensitive ratiometric fluorescent probe based on fluorescein coumarin for detecting hydrazine in actual water and biological samples.

Hydrazine (N2 H4 ) is a highly toxic and harmful chemical reagent. Fluorescent probes are simple and efficient tools for sensitive monitoring of N2 H4 enrichment in the environment, humans, animals, and plants. In this work, a ratiometric fluorescent probe (FP-1) containing coumarin was used for hydrazine detection. The proposed FP-1 probe had a linear detection range of 0-250 µM and a limit of detection (LOD) of 0.059 µM (1.89 ppb). A large red Stokes shift was observed in fluorescence and UV-vis absorption spectra due to the hydrolysis of ester bonds between FP-1 and hydrazine. The hydrazine detection mechanism of FP-1 was also investigated using density functional theory (DFT) calculations. Finally, FP-1 could sensitively and selectively monitor hydrazine in actual water samples and BEAS-2B cells. Therefore, it has great application potential in environmental monitoring and disease diagnosis.

The m6 A reader SiYTH1 enhances drought tolerance by affecting the messenger RNA stability of genes related to stomatal closure and reactive oxygen species scavenging in Setaria italica.

Foxtail millet (Setaria italica), a vital drought-resistant crop, plays a significant role in ensuring food and nutritional security. However, its drought resistance mechanism is not fully understood. N6 -methyladenosine (m6 A) modification of RNA, a prevalent epi-transcriptomic modification in eukaryotes, provides a binding site for m6 A readers and affects plant growth and stress responses by regulating RNA metabolism. In this study, we unveiled that the YT521-B homology (YTH) family gene SiYTH1 positively regulated the drought tolerance of foxtail millet. Notably, the siyth1 mutant exhibited reduced stomatal closure and augmented accumulation of excessive H2 O2 under drought stress. Further investigations demonstrated that SiYTH1 positively regulated the transcripts harboring m6 A modification related to stomatal closure and reactive oxygen species (ROS) scavenging under drought stress. SiYTH1 was uniformly distributed in the cytoplasm of SiYTH1-GFP transgenic foxtail millet. It formed dynamic liquid-like SiYTH1 cytosol condensates in response to drought stress. Moreover, the cytoplasmic protein SiYTH1 was identified as a distinct m6 A reader, facilitating the stabilization of its directly bound SiARDP and ROS scavenging-related transcripts under drought stress. Furthermore, natural variation analysis revealed SiYTH1AGTG as the dominant allele responsible for drought tolerance in foxtail millet. Collectively, this study provides novel insights into the intricate mechanism of m6 A reader-mediated drought tolerance and presents a valuable genetic resource for improving drought tolerance in foxtail millet breeding.

Dynamic mRNA and miRNA expression of the head during early development in bighead carp (Hypophthalmichthys nobilis).

BACKGROUND: Head of fish species, an exquisitely complex anatomical system, is important not only for studying fish evolution and development, but also for economic values. Currently, although some studies have been made on fish growth and body shapes, very limited information is available on the molecular mechanism of head development. RESULTS: In this study, RNA sequencing (RNA-Seq) and small RNA sequencing (sRNA-Seq) technologies were used to conduct integrated analysis for the head of bighead carp at different development stages, including 1, 3, 5, 15 and 30 Dph (days post hatch). By RNA-Seq data, 26 pathways related to growth and bone formation were identified as the main physiological processes during early development. Coupling this to sRNA-Seq data, we picked out six key pathways that may be responsible for head development, namely ECM receptor interaction, TNF signaling pathway, osteoclast differentiation, PI3K-Akt signaling pathway, Neuroactive ligand-receptor interaction and Jak-STAT signaling pathway. Totally, 114 important candidate genes from the six pathways were obtained. Then we found the top 20 key genes according to the degree value by cytohubba, which regulated cell growth, skeletal formation and blood homeostasis, such as pik3ca, pik3r1, egfr, vegfa, igf1 and itga2b. Finally, we also acquired 19 key miRNAs playing multiple roles in the perfection of various tissues in the head (such as brain, eye and mouth) and mineralization of head bone system, such as let-7e, miR-142a-5p, miR-144-3p, miR-23a-3p and miR-223. CONCLUSIONS: Results of this study will be informative for genetic mechanisms of head development and also provide potential candidate targets for the interaction regulation during early growth in bighead carp.

USP44 positively regulates innate immune response to DNA viruses through deubiquitinating MITA.

Mediator of IRF3 activation (MITA, also known as stimulator of interferon genes, STING) senses the second messenger cyclic GMP-AMP (cGAMP) which is synthesized upon DNA virus infection and activates innate antiviral immune response. It has been demonstrated that the activity of MITA is delicately regulated by various post-translational modifications including polyubiquitination. In this study, we identified the deubiquitinating enzyme USP44 as a positive regulator of MITA. USP44 is recruited to MITA following DNA virus infection and removes K48-linked polyubiquitin moieties from MITA at K236, therefore prevents MITA from proteasome mediated degradation. USP44-deficiency results in acceleration of HSV-1-induced degradation of MITA and reduced induction of type I interferons (IFNs) and proinflammatory cytokines. Consistently, Usp44-/- mice are more susceptible to HSV-1 infection as indicated by higher tissue viral titers, greater tissue damage and lower survival rate. These findings suggest that USP44 plays a specific and critical role in the regulation of innate immune response against DNA viruses.

Phase-shift-mediated sensitive detection of propagating ultra-confined graphene plasmons.

The ultra-confined plasmon field supported by graphene provides an ideal platform for enhanced light-matter interactions and studies of fundamental physical phenomena. On the other hand, the intrinsic ultra-short plasmon wavelength obstructs in-plane detectability of plasmon behaviors, like wavelength variations induced by biomolecule or dragging current. The detection of plasmon wavefront and its spatial shift relies on scattering-type scanning near-field microscopy with a spatial resolution of 20 nm. Here we propose a configuration which can efficiently separate ultra-confined plasmon region from detection region, guaranteeing both field confinement and in-plane sensitive detection of wavelength variations. As an example, the application in detecting Fizeau drag effect is demonstrated. Our study can be applied for detecting strong light-matter interactions, including fundamental physical studies and biosensing applications.

Asymmetric Synthesis of Chromans Through Bifunctional Enamine-Metal Lewis Acid Catalysis.

Cooperative enamine-metal Lewis acid catalysis has emerged as a powerful tool to construct carbon-carbon and carbon-heteroatom bond forming reactions. A concise synthetic method for asymmetric synthesis of chromans from cyclohexanones and salicylaldehydes has been developed to afford tricyclic chromans containing three consecutive stereogenic centers in good yields (up to 87 %) and stereoselectivity (up to 99 % ee and 11 : 1 : 1 dr). This difficult organic transformation was achieved through bifunctional enamine-metal Lewis acid catalysis. It is believed that the strong activation of the salicylaldehydes through chelating to the metal Lewis acid and the bifunctional nature of the catalyst accounts for the high yields and enantioselectivity of the reaction. The absolute configurations of the chroman products were established through X-ray crystallography. DFT calculations were conducted to understand the mechanism and stereoselectivity of this reaction.

Preparation of a disposable electrochemiluminescence sensor chip based on an MXene-loaded ruthenium luminescent agent and its application in the detection of carcinoembryonic antigens.

Carcinoembryonic antigen (CEA) is an important cancer marker that plays a significant role in achieving low-cost, rapid and highly sensitive clinical detection. In this work, we developed a disposable electrochemiluminescence (ECL) sensor chip based on a screen-printed electrode (SPE) for detecting CEA via ECL technology. An amino-modified Ti3C2 MXene was used as a carrier to successfully prepare a highly efficient ECL probe AuNPs-Ru-Arg@NH2-Ti3C2-MXene by loading with AuNPs-Arg through covalent links and modifying with a ruthenium complex. Upon the addition of CEA, the ECL signal decreased significantly with the increase of CEA, due to the formation of immune complexes at the interface of the electrode. The sensing chip was used to detect CEA in an aqueous solution and found to have a detection limit of 1.5 pg mL-1. The chip was used to determine CEA in the serum of healthy humans and cancer patients, and the results were consistent with those obtained using ELISA. The disposable ECL sensor chip has many advantages including convenience, rapid detection, low cost and easy mass production; thus it has great application potential in clinical cancer diagnosis.

Update: Innate Lymphoid Cells in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic and nonspecific intestinal inflammatory condition with high relapse rate. Its pathogenesis has been linked to dysbacteriosis, genetic and environmental factors. In recent years, a new type of lymphocytes, termed innate lymphoid cells, has been described and classified into three subtypes of innate lymphoid cells-group 1, group 2 and group 3. An imbalance among these subsets' interaction with gut microbiome, and other immune cells affects intestinal mucosal homeostasis. Understanding the role of innate lymphoid cells may provide ideas for developing novel and targeted approaches for treatment of IBD.

A sensitive electrochemiluminescent sensor chip based on the ssDNA-Ru(II) complex and aptamer for the determination of thrombin.

In this work, an electrochemiluminescence (ECL) sensor chip for sensitive detection of thrombin (TB) was prepared using a screen-printed electrode (SPE) as a working electrode and an aptamer as a specific recognition moiety. To produce an ECL sensor chip, a layer of pL-Cys was immobilized on the surface of the SPE using the cyclic voltammetry scanning method. A layer of gold nanoparticles (AuNPs) was assembled through an Au-S bond and hairpin DNA was further immobilized on the electrode surface. Ru(bpy)2 (mcpbpy)2+ , as a luminescent reagent, was covalently bound to single-stranded DNA (ssDNA) to prepare a luminescence probe ssDNA-Ru. The probe was hybridized with TB aptamer to form a capture probe. In the presence of TB, the TB aptamer in the capture probe bound to TB, causing the release of ssDNA-Ru that could bind to hairpin DNA on the electrode surface. The Ru(II) complex as a luminescent reagent was assembled onto the electrode, and pL-Cys was used as a co-reactant to enhance the ECL efficiency. The ECL signal of the sensor chip generated based on the above principles had a linear relationship with log TB concentration at the range 10 fM to1 nM, and the detection limit was 0.2 fM. Finally, TB detection using this method was verified using real blood samples. This work provides a new method using an aptamer as a foundation and SPE as a material for the detection of biological substances.

Nanoinfrared Characterization of Bilayer Graphene Conductivity under Dual-Gate Tuning.

Dual-gate tuning on two-dimensional (2D) heterostructures can provide independent control of the carrier concentration and interlayer electrostatic potential, yielding novel electronic and optical properties. In this paper, by utilizing monolayer graphene as both the top gate and a plasmon wavelength magnifier, the optical properties of bilayer graphene (BLG) under dual-gate are quantitatively investigated by nanoinfrared imaging. The hybrid optical modes in the vertically coupled two-layer system are imaged from scattering-type scanning near-field microscopy (s-SNOM). Moreover, plasmon dispersion behaviors under varied dual-gate tuning are explored and explained well with theoretical ones employing tight binding approximation, which reveals the flexibility in individually manipulating the Fermi energy and bandgap. Especially, electron-hole asymmetry in BLG is verified from experiments. Our studies pave route for quantitative near-field investigation of superlattice, topological boundaries, and other emergent phenomena in graphene-based 2D heterostructures.

Human Cytomegalovirus Protein UL94 Targets MITA to Evade the Antiviral Immune Response.

Cyclic GMP-AMP synthase (cGAS) senses double-stranded DNA and synthesizes the second messenger cyclic GMP-AMP (cGAMP), which binds to mediator of IRF3 activation (MITA) and initiates MITA-mediated signaling, leading to induction of type I interferons (IFNs) and other antiviral effectors. Human cytomegalovirus (HCMV), a widespread and opportunistic pathogen, antagonizes the host antiviral immune response to establish latent infection. Here, we identified HCMV tegument protein UL94 as an inhibitor of the cGAS-MITA-mediated antiviral response. Ectopic expression of UL94 impaired cytosolic double-stranded DNA (dsDNA)- and DNA virus-triggered induction of type I IFNs and enhanced viral replication. Conversely, UL94 deficiency potentiated HCMV-induced transcription of type I IFNs and downstream antiviral effectors and impaired viral replication. UL94 interacted with MITA, disrupted the dimerization and translocation of MITA, and impaired the recruitment of TBK1 to the MITA signalsome. These results suggest that UL94 plays an important role in the immune evasion of HCMV.IMPORTANCE Human cytomegalovirus (HCMV), a large double-stranded DNA (dsDNA) virus, encodes more than 200 viral proteins. HCMV infection causes irreversible abnormalities of the central nervous system in newborns and severe syndromes in organ transplantation patients or AIDS patients. It has been demonstrated that HCMV has evolved multiple immune evasion strategies to establish latent infection. Previous studies pay more attention to the mechanism by which HCMV evades immune response in the early phase of infection. In this study, we identified UL94 as a negative regulator of the innate immune response, which functions in the late phase of HCMV infection.

The heterogeneous nuclear ribonucleoprotein hnRNPM inhibits RNA virus-triggered innate immunity by antagonizing RNA sensing of RIG-I-like receptors.

Recognition of viral RNA by the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), including RIG-I and MDA5, initiates innate antiviral responses. Although regulation of RLR-mediated signal transduction has been extensively investigated, how the recognition of viral RNA by RLRs is regulated remains enigmatic. In this study, we identified heterogeneous nuclear ribonucleoprotein M (hnRNPM) as a negative regulator of RLR-mediated signaling. Overexpression of hnRNPM markedly inhibited RNA virus-triggered innate immune responses. Conversely, hnRNPM-deficiency increased viral RNA-triggered innate immune responses and inhibited replication of RNA viruses. Viral infection caused translocation of hnRNPM from the nucleus to the cytoplasm. hnRNPM interacted with RIG-I and MDA5, and impaired the binding of the RLRs to viral RNA, leading to inhibition of innate antiviral response. Our findings suggest that hnRNPM acts as an important decoy for excessive innate antiviral immune response.

Can Primary Arylamines Form Enamine? Evidence, α-Enaminone, and [3+3] Cycloaddition Reaction.

The formation of enamine from primary arylamines was detected and confirmed by nuclear magnetic resonance spectroscopy. The presence of a radical quencher, e.g., (2,2,6,6-tetramethylpiperidin-1-yl)oxidanyl, was found to be essential for the detection of enamine formation. A direct synthesis of α-enaminones from primary arylamines and ketones was also developed. Mechanistic investigation of α-enaminone formation suggests that an amine radical cation generated through O2 singlet energy transfer was involved in initiating α-enaminone formation. The reactivity and utility of α-enaminones were explored with a [3+3] cycloaddition reaction of enones affording dihydropyridines in good yields (58-85%). α-Enaminones displayed a set of reactivities that is different from that of enamines. The knowledge gained in this work advances our basic understanding of organic chemistry, providing insights and new opportunities in enamine catalysis.

YIPF5 Is Essential for Innate Immunity to DNA Virus and Facilitates COPII-Dependent STING Trafficking.

STING plays central roles in the innate immune response to pathogens that contain DNA. Sensing cytoplasmic DNA by cyclic GMP-AMP synthase produces cyclic GMP-AMP, which binds to and activates STING and induces STING translocation from the endoplasmic reticulum to the perinuclear microsome. However, this trafficking process has not been fully elucidated yet. In this study, we identified YIPF5 as a positive regulator of STING trafficking. YIPF5 is essential for DNA virus- or intracellular DNA-triggered production of type I IFNs. Consistently, knockdown of YIPF5 impairs cellular antiviral responses to DNA virus. Mechanistically, YIPF5 interacts with both STING and components of COPII, facilitating STING recruitment to COPII in the presence of cytoplasmic dsDNA. Furthermore, knockdown of components of COPII inhibits DNA virus-triggered production of type I IFNs, suggesting that COPII is involved in innate immune responses to DNA viruses. Collectively, our findings demonstrate that YIPF5 positively regulates STING-mediated innate immune responses by recruiting STING to COPII-coated vesicles and facilitating STING trafficking from the endoplasmic reticulum to Golgi, providing important insights into the molecular mechanisms of intracellular DNA-stimulated STING trafficking and activation.

Comparison between modified wet suction and dry suction technique for endoscopic ultrasound-guided fine-needle biopsy in pancreatic solid lesions.

BACKGROUND AND AIM: Although endoscopic ultrasound-guided fine-needle biopsy is widely applied, there is no clear consensus on the optimal biopsy technique. We described a modified wet suction technique (MWEST) with the aim to compare the efficacy and safety between MWEST and the dry suction technique (DST). METHODS: In this prospective, randomized, crossover, single-blinded study, patients with suspected pancreatic malignancy were randomized to the DST (group A) or MWEST (group B) for the first pass, and the two techniques were performed alternately. The primary outcome was the comparison of specimen adequacy and diagnostic yield between the techniques. Secondary outcomes included the macroscopic visible core length, blood contamination of specimens, and adverse events of both techniques. RESULTS: From January 2019 to September 2019, 216 passes were performed in 50 patients. The specimen adequacy was significantly higher in "per-lesion" (P = 0.026), "per-pass" (cytology: P = 0.034; histology: P = 0.042), and first-pass analysis (P = 0.034) for MWEST than for DST. In diagnostic yield, MWEST showed significantly superior histological yield (P = 0.014) and first-pass analysis (κ: MWEST: 0.743 and DST: 0.519) compared with DST. The median macroscopic visible core lengths were 8 mm (interquartile range: 3.25-15 mm) and 10 mm (interquartile range: 5.25-15 mm) for DST and MWEST, respectively (P = 0.036). Blood contamination was significantly more serious in DST than in MWEST (cytology: P = 0.021; histology: P = 0.042). CONCLUSIONS: Endoscopic ultrasound-guided fine-needle biopsy with MWEST resulted in significantly better quality of specimen, histological, and first-pass diagnostic yields and comparable safety compared with the DST. MWEST is preferred for endoscopic ultrasound-guided fine-needle biopsy in pancreatic solid lesions.