Helicase protein DDX11 as a novel antiviral factor promoting RIG-I-MAVS-mediated signaling pathway.

Type Ι interferon (IFN) production mediated by retinoic acid-inducible gene 1 (RIG-I) and mitochondrial antiviral signaling protein (MAVS) is essential for antiviral innate immune responses. Here, we report the identification of a novel co-sensor for cytosolic nucleic acids: DEAD/H-box helicase 11 (DDX11), a member of the DExD/H (Asp-Glu-x-Asp/His)-box helicase family. Knockdown or knockout of DDX11 attenuated the ability of cells to increase IFN-ß, IFN-stimulated gene 56, and C-X-C motif chemokine ligand 10 in response to SeV and poly (I:C) by blocking the activation of TANK-binding kinase 1 and IFN regulatory factor 3. Nucleic acid sensing by DDX11 was independent of the stimulator of IFN genes but was dependent on RIG-I and MAVS. DDX11 regulated RIG-I-MAVS-mediated IFN signaling by specifically interacting with nucleic acid, RIG-I, and MAVS to enhance RIG-I-double-strand RNA and RIG-I-MAVS binding affinity. Overall, our results identified a critical role for DDX11 in the innate immune response and provided molecular insights into the mechanisms by which DDX11 recognized cytosolic nucleic acid and interacted with RIG-Ι and MAVS for potent IFN signaling and antiviral immunity. IMPORTANCE: Innate immunity is the first and most rapid host defense against virus infection. Recognition of viral RNA by the retinoic acid-inducible gene 1 (RIG-I)-like receptors (RLRs) initiates innate antiviral immune responses. How the binding of viral RNA to and activation of the RLRs are regulated remains enigmatic. In this study, we identified DEAD/H-box helicase 11 (DDX11) as a positive regulator of the RIG-I-mitochondrial antiviral signaling protein (MAVS)-mediated signaling pathways. Mechanistically, we demonstrated that DDX11 bound to viral RNA, interacted with RIG-I, and promoted their binding to viral RNA. DDX11 also promoted the interaction between RIG-I and MAVS and activation of RIG-I-MAVS signaling. Overall, our results elucidate the role of DDX11 in RIG-I-MAVS-dependent signaling pathways and may shed light on innate immune gene regulation.

Correction: Liu et al. Cholesterol 25-Hydroxylase Suppresses Swine Acute Diarrhea Syndrome Coronavirus Infection by Blocking Spike Protein-Mediated Membrane Fusion. Viruses 2023, 15, 2406.

In the original publication [...].

Curcumin inhibits the growth and invasion of gastric cancer by regulating long noncoding RNA AC022424.2.

BACKGROUND: Gastric cancer, characterized by a multifactorial etiology and high heterogeneity, continues to confound researchers in terms of its pathogenesis. Curcumin, a natural anticancer agent, exhibits therapeutic promise in gastric cancer. Its effects include promoting cell apoptosis, curtailing tumor angiogenesis, and enhancing sensitivity to radiation and chemotherapy. Long noncoding RNAs (lncRNAs) have garnered significant attention as biomarkers for early screening, diagnosis, treatment, and drug response because of their remarkable specificity and sensitivity. Recent investigations have revealed an association between aberrant lncRNA expression and early diagnosis, clinical staging, metastasis, drug sensitivity, and prognosis in gastric cancer. A profound understanding of the intricate mechanisms through which lncRNAs influence gastric cancer development can provide novel insights for precision treatment and tailored management of patients with gastric cancer. This study aimed to unravel the potential of curcumin in suppressing the malignant behavior of gastric cancer cells by upregulating specific lncRNAs and modulating gastric cancer onset and progression. AIM: To identify lncRNAs associated with curcumin treatment and investigate the role of lncRNA AC022424.2 in the effects of curcumin on gastric cancer cell apoptosis, proliferation, and invasion. Furthermore, these findings were validated in clinical samples. METHODS: The study employed CCK-8 assays to assess the impact of curcumin on gastric cancer cell proliferation, flow cytometry to investigate its effects on apoptosis, and scratch and Transwell assays to evaluate its influence on the migration and invasion of BGC-823 and MGC-803 cells. Western blotting was used to gauge changes in the protein expression levels of CDK6, CDK4, Bax, Bcl-2, caspase-3, P65, and the PI3K/Akt/mTOR pathway in gastric cancer cell lines after curcumin treatment. Differential expression of lncRNAs before and after curcumin treatment was assessed using lncRNA sequencing and validated using quantitative reverse transcription polymerase chain reaction (qRT-PCR) in BGC-823 and MGC-803 cells. AC022424.2-1 knockdown BGC-823 and MGC-803 cells were generated to scrutinize the impact of lncRNA AC022424.2 on apoptosis, proliferation, migration, and invasion of gastric cancer cells. Western blotting was performed to ascertain changes in the expression of proteins implicated in the PI3K/Akt/mTOR and NF-κB signaling pathways. RT-PCR was employed to measure lncRNA AC022424.2 expression in clinical gastric cancer tissues and to correlate its expression with clinical pathological characteristics. RESULTS: Curcumin induced apoptosis and hindered proliferation, migration, and invasion of gastric cancer cells in a dose- and time-dependent manner. LncRNA AC022424.2 was upregulated after curcumin treatment, and its knockdown enhanced cancer cell aggressiveness. LncRNA AC022424.2 may have affected cancer cells via the PI3K/Akt/mTOR and NF-κB signaling pathways. LncRNA AC022424.2 downregulation was correlated with lymph node metastasis, making it a potential diagnostic and prognostic marker. CONCLUSION: Curcumin has potential anticancer effects on gastric cancer cells by regulating lncRNA AC022424.2. This lncRNA plays a significant role in cancer cell behavior and may have clinical implications in diagnosis and prognosis evaluation. The results of this study enhance our understanding of gastric cancer development and precision treatment.

Swine acute diarrhea syndrome coronavirus nucleocapsid protein antagonizes the IFN response through inhibiting TRIM25 oligomerization and functional activation of RIG-I/TRIM25.

Swine acute diarrhea syndrome coronavirus (SADS-CoV), an emerging Alpha-coronavirus, brings huge economic loss in swine industry. Interferons (IFNs) participate in a frontline antiviral defense mechanism triggering the activation of numerous downstream antiviral genes. Here, we demonstrated that TRIM25 overexpression significantly inhibited SADS-CoV replication, whereas TRIM25 deficiency markedly increased viral yield. We found that SADS-CoV N protein suppressed interferon-beta (IFN-ß) production induced by Sendai virus (SeV) or poly(I:C). Moreover, we determined that SADS-CoV N protein interacted with RIG-I N-terminal two caspase activation and recruitment domains (2CARDs) and TRIM25 coiled-coil dimerization (CCD) domain. The interaction of SADS-CoV N protein with RIG-I and TRIM25 caused TRIM25 multimerization inhibition, the RIG-I-TRIM25 interaction disruption, and consequent the IRF3 and TBK1 phosphorylation impediment. Overexpression of SADS-CoV N protein facilitated the replication of VSV-GFP by suppressing IFN-ß production. Our results demonstrate that SADS-CoV N suppresses the host IFN response, thus highlighting the significant involvement of TRIM25 in regulating antiviral immune defenses.

Buried-Interface Engineering Enables Efficient and 1960-Hour ISOS-L-2I Stable Inverted Perovskite Solar Cells.

High-performance perovskite solar cells (PSCs) typically require interfacial passivation, yet this is challenging for the buried interface, owing to the dissolution of passivation agents during the deposition of perovskites. Here, this limitation is overcome with in situ buried-interface passivation-achieved via directly adding a cyanoacrylic-acid-based molecular additive, namely BT-T, into the perovskite precursor solution. Classical and ab initio molecular dynamics simulations reveal that BT-T spontaneously may self-assemble at the buried interface during the formation of the perovskite layer on a nickel oxide hole-transporting layer. The preferential buried-interface passivation results in facilitated hole transfer and suppressed charge recombination. In addition, residual BT-T molecules in the perovskite layer enhance its stability and homogeneity. A power-conversion efficiency (PCE) of 23.48% for 1.0 cm2 inverted-structure PSCs is reported. The encapsulated PSC retains 95.4% of its initial PCE following 1960 h maximum-power-point tracking under continuous light illumination at 65 °C (i.e., ISOS-L-2I protocol). The demonstration of operating-stable PSCs under accelerated ageing conditions represents a step closer to the commercialization of this emerging technology.

Cholesterol 25-Hydroxylase Suppresses Swine Acute Diarrhea Syndrome Coronavirus Infection by Blocking Spike Protein-Mediated Membrane Fusion.

Swine acute diarrhea syndrome coronavirus (SADS-CoV) is an emerging porcine intestinal coronavirus that can cause acute diarrhea, vomiting, rapid weight loss, and high mortality in newborn piglets. Cholesterol 25-hydroxylase (CH25H) is a molecular mediator of innate antiviral immunity and converts cholesterol to 25-hydroxycholesterol (25HC). Previous studies have reported that CH25H and 25HC have an antiviral effect against multiple viruses. However, the interplay between SADS-CoV infection and CH25H or 25HC is still uncertain. Here, we found that CH25H and its enzymatic product 25HC restrained SADS-CoV replication by blocking membrane fusion. Our results show that CH25H was upregulated by SADS-CoV infection in vitro and in vivo, and that it was an IFN-stimulated gene in porcine ileum epithelial cells. Moreover, CH25H and CH25H mutants lacking catalytic activity can inhibit SADS-CoV replication. Furthermore, 25HC significantly suppressed SADS-CoV infection by inhibiting virus entry. Notably, we confirmed that CH25H and 25HC blocked SADS-CoV spike protein-mediated membrane fusion. Our data provide a possible antiviral therapy against SADS-CoV and other conceivable emerging coronaviruses in the future.

RNA-binding protein ENO1 promotes the tumor progression of gastric cancer by binding to and regulating gastric cancer-related genes.

Background: This study sought to identify the downstream target genes of enolase 1 (ENO1), clarify the role of ENO1 in gastric cancer (GC), and provide novel insights into the regulatory mechanisms of ENO1 in the occurrence and development of GC. Methods: We performed RNA-immunoprecipitation sequencing in MKN-45 cells to study the types and abundance of pre-messenger RNA (mRNA)/mRNA bound by ENO1, the binding sites and motifs, the relationship between ENO1 binding and its regulation of transcription level, and alternative splicing level by combining with RNA-sequencing (RNA-seq) data to further clarify the role of ENO1 in GC. Results: We found that ENO1 stabilized the expression of SRY-box transcription factor 9 (SOX9), vascular endothelial growth factor A (VEGFA), G protein-coupled receptor class C group 5 member A (GPRC5A), and myeloid cell leukemia-1 (MCL1) by binding to their mRNA, which increased the growth of GC. In addition, ENO1 interacted with some other long non-coding RNAs (lncRNAs) or small-molecule kinases, such as NEAT1, LINC00511, CD44, and pyruvate kinase M2 (PKM2), to regulate their expression to affect cell proliferation, migration, and apoptosis. Conclusions: ENO1 may play a role in GC by binding to and regulating GC-related genes. Our findings extend understandings of its mechanism as a clinical therapeutic target.

Autophagy is induced by swine acute diarrhea syndrome coronavirus through the cellular IRE1-JNK-Beclin 1 signaling pathway after an interaction of viral membrane-associated papain-like protease and GRP78.

Autophagy plays an important role in the infectious processes of diverse pathogens. For instance, cellular autophagy could be harnessed by viruses to facilitate replication. However, it is still uncertain about the interplay of autophagy and swine acute diarrhea syndrome coronavirus (SADS-CoV) in cells. In this study, we reported that SADS-CoV infection could induce a complete autophagy process both in vitro and in vivo, and an inhibition of autophagy significantly decreased SADS-CoV production, thus suggesting that autophagy facilitated the replication of SADS-CoV. We found that ER stress and its downstream IRE1 pathway were indispensable in the processes of SADS-CoV-induced autophagy. We also demonstrated that IRE1-JNK-Beclin 1 signaling pathway, neither PERK-EIF2S1 nor ATF6 pathways, was essential during SADS-CoV-induced autophagy. Importantly, our work provided the first evidence that expression of SADS-CoV PLP2-TM protein induced autophagy through the IRE1-JNK-Beclin 1 signaling pathway. Furthermore, the interaction of viral PLP2-TMF451-L490 domain and substrate-binding domain of GRP78 was identified to activate the IRE1-JNK-Beclin 1 signaling pathway, and thus resulting in autophagy, and in turn, enhancing SADS-CoV replication. Collectively, these results not only showed that autophagy promoted SADS-CoV replication in cultured cells, but also revealed that the molecular mechanism underlying SADS-CoV-induced autophagy in cells.

Circular RNA Circ-0002570 Accelerates Cancer Progression by Regulating VCAN via MiR-587 in Gastric Cancer.

BACKGROUND: Circular RNAs (circRNAs) are closely associated with the occurrences and progress of gastric cancer (GC). We aimed to delve into the function and pathological mechanism of Circular RNA-0002570 (circ-0002570) in GC progression. METHODS: CircRNAs differentially expressed in GC were screened using bioinformatics technology. The expression of circ-0002570 was detected in GC specimens and cells via qRT-PCR, and the prognostic values of circ-0002570 were determined. The functional roles of circ-0002570 on proliferation, migration, and invasion in GC cells were explored in vitro and in vivo. Interaction of circ-0002570, miR-587, and VCAN was confirmed by dual-luciferase reporter assays, Western blotting, and rescue experiments. RESULTS: Circ-0002570 expression was distinctly increased in GC tissues compared to adjacent normal specimens, and GC patients with higher circ-0002570 expressions displayed a short survival. Functionally, knockdown of circ-0002570 resulted in the inhibition of cell proliferation, migration, and invasion, and suppressed tumor growth in vivo. Mechanistically, miR-587 was sponged by circ-0002570. VCAN expression in NSCLC was directly inhibited by miR-587. Overexpression of circ-0002570 prevented VCAN from miR-587-mediated degradation and thus facilitated GC progression. CONCLUSION: The circ-0002570-miR-587-VCAN regulatory pathway promoted the progression of GC. Our findings provided potential new targets for the diagnosis and therapy of GC.

CBX2 depletion inhibits the proliferation, invasion and migration of gastric cancer cells by inactivating the YAP/ß-catenin pathway.

Gastric cancer (GC) is the most common and fast­growing malignancy of the digestive system, which has a high mortality. Chromobox homolog 2 (CBX2) has been reported to be highly expressed in cancer tissues compared with adjacent normal tissues. It has also been established that CBX2 is upregulated in GC cell lines by searching the Cancer Cell Line Encyclopedia. The aim of the present study was to investigate the biomolecular role and underlying mechanism of CBX2 in the proliferation, invasion and migration of GC cells. Short hairpin RNA­CBX2 and yes­associated protein (YAP) overexpression plasmids were constructed to regulate CBX2 and YAP expression, respectively. Additionally, the expression of certain mRNAs and proteins involved in the YAP/ß­catenin pathway and those associated with cell invasion were assessed by western blotting and reverse transcription­quantitative PCR, respectively. The cellular behaviors of MFC cells were analyzed using Cell Counting Kit­8, colony formation wound­healing and Transwell assays. The results of the present study revealed that increased CBX2 expression was observed in GC cell lines compared with normal gastric cells. In addition, CBX2 knockdown inhibited the nuclear cytoplasm translocation of YAP, inducing its phosphorylation, and suppressing the activation of the ß­catenin signaling pathway. The results also demonstrated that CBX2 depletion inhibited the proliferation, migration and invasion of GC cells by inactivating the YAP/ß­catenin pathway. It was determined that CBX2 promoted the proliferation, invasion and migration of GC cells by activating the YAP/ß­catenin pathway, suggesting that CBX2 is involved in the pathogenesis of GC and may represent a novel target for the clinical treatment of GC.

Circ_002117 binds to microRNA-370 and promotes endoplasmic reticulum stress-induced apoptosis in gastric cancer.

BACKGROUND: Mounting evidence implicates circular RNAs (circRNAs) in various biological processes during cancer progression. Gastric cancer is a main cause of cancer-related deaths worldwide. Herein, we aimed at investigating whether circ_002117 mediates gastric cancer progression through endoplasmic reticulum (ER) stress. METHODS: Bioinformatics analysis detected differentially expressed circRNAs and their target miRNA candidates, and RT-qPCR was performed to detect expression of circ_002117, microRNA (miRNA)-370 and HERPUD1 in gastric cancer tissues and cells. Gastric cancer cells were transfected with plasmids and their proliferative ability and apoptosis were detected with gain- and loss-of-function assay. The ER of treated cells was observed under a transmission electron microscope. Dual-luciferase reporter gene assay and RIP were performed to detect the interaction between HEPRUD1, miR-370 and circ_002117-treated cells were injected into mice to establish xenograft tumor model. RESULTS: Circ_002117 and HEPRUD1 were poorly expressed whereas miR-370 was highly expressed in clinical cancer tissues and cells. Circ_002117 was indicated to target and suppress miR-370 expression, while HERPUD1 was directly targeted by miR-370. Circ_002117 overexpression or miR-370 deficiency promoted ER stress-induced apoptosis and decreased proliferation of gastric cancer cells, which was reversed by silencing of HEPRUD1. Circ_002117 overexpression or miR-370 depletion significantly suppressed gastric cancer tumorigenesis in vivo. CONCLUSIONS: Taken altogether, circ_002117 facilitated ER stress-induced apoptosis in gastric cancer by upregulating HERPUD1 through miR-370 inhibition.

Arabidopsis guard cell CO2/HCO3 - response mutant screening by an aequorin-based calcium imaging system.

BACKGROUND: The increase in atmospheric CO2 is causing a number of changes in plant growth such as increases in leaf area and number, branching, plant size and biomass, and growth rate. Despite the importance of stomatal responses to CO2, little is known about the genetic and molecular mechanisms that mediate stomatal development and movement in response to CO2 levels. Deciphering the mechanisms that sense changes in CO2 and/or HCO3 - concentration is critical for unraveling the role of CO2 in stomatal development movement. In Arabidopsis, CO2-induced stomatal closure is strongly Ca2+-dependent. To further dissect this signaling pathway and identify new components in the CO2 response pathway, we recorded [Ca2+]cyt changes in mutagenized Arabidopsis leaves and screened for mutants with abnormal guard cell behavior in response to CO2/HCO3 -. RESULTS: We observed that 1 mM HCO3 - induces [Ca2+]cys transient changes in guard cells and stomatal closure both in light and darkness. The changes in [Ca2+]cys induced by HCO3 - could be detected by an aequorin-based calcium imaging system. Using this system, we identified a number of Arabidopsis mutants defective in both [Ca2+]cyt changes and the stomatal response to CO2/HCO3 -. CONCLUSIONS: We provide a sensitive method for isolating stomatal CO2/HCO3 - response genes that function early in stomatal closure and that have a role in regulating [Ca2+]cyt. This method will be helpful in elucidating the Ca2+-dependent regulation of guard cell behavior in response to CO2/HCO3 -.