OBJECTIVES: To investigate the mechanism of DDX17 for regulating proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) during the development of pulmonary hypertension (PH). METHODS: In murine PASMCs cultured under normoxic or hypoxic conditions, the effects of transfection with si-Ddx17 and insulin treatment, alone or in combination, on cell proliferation and migration were evaluated using Ki-67 immunofluorescence staining, scratch assay and Transwell assay. Western Blotting was performed to detect the changes in protein expression levels of DDX17, 4EBP1, S6, p-4EBP1, and p-S6. In a mouse model of PH induced by intraperitoneal injection of monocrotaline (MCT), the changes in pulmonary vasculature were examined using HE staining following tail vein injection of AD-Ddx17i. RESULTS: The PASMCs in hypoxic culture exhibited significantly enhanced cell proliferation and migration and protein expressions of p-4EBP1 and p-S6, and these changes were obviously reversed by transfection with si-Ddx17. Treatment with insulin significantly attenuated the effect of si-Ddx17 against hypoxic exposure-induced changes in PASMCs. In the mouse model of MCT-induced PH, transfection with AD-Ddx17i obviously alleviated pulmonary vascular stenosis and intimal hyperplasia. CONCLUSIONS The expression of DDX17 is elevated in hypoxia-induced PASMCs and PH mice, and silencing DDX17 significantly inhibits PASMC proliferation and migration in vitro and pulmonary vascular remodeling in PH mice by reducing mTORC1 activity.
Animals ; Cell Proliferation ; Cell Movement ; DEAD-box RNA Helicases/metabolism* ; Myocytes, Smooth Muscle/metabolism* ; Mice ; Pulmonary Artery/cytology* ; Hypertension, Pulmonary/metabolism* ; Mechanistic Target of Rapamycin Complex 1 ; Cells, Cultured ; Muscle, Smooth, Vascular/cytology*

Geminiviruses cause substantial crop yield losses worldwide. The replication initiator protein (Rep) encoded by geminiviruses is indispensable for geminiviral replication. The Rep protein encoded by beet severe curly top virus (BSCTV, genus Curtovirus, family Geminiviridae) induces VARIANT IN METHYLATION 5 (VIM5) expression in Arabidopsis leaves upon BSCTV infection. VIM5 functions as a ubiquitination-related E3 ligase to promote the proteasomal degradation of methyltransferases, resulting in reduction of methylation levels in the BSCTV C2-3 promoter. However, the specific domains of Rep responsible for VIM5 induction remain poorly characterized. Although Rep proteins from several geminiviruses act as viral suppressors of RNA silencing (VSRs), whether BSCTV Rep also possesses VSR activity remains to be illustrated. In this study, we employed a transient expression system in the 16c-GFP transgenic and the wild-type Nicotiana benthamiana plants to analyze the VSR and the VIM5-inducing activities of different truncated Rep proteins haboring distinct domains. We found that the N-terminal domain (amino acids 1-180) of Rep suppressed GFP silencing in 16c-GFP transgenic N. benthamiana leaves. The minimal N-terminal fragment (amino acids 1-104) induced VIM5 expression upon co-infiltration, while C-terminal truncations lacked VIM5-inducing activity. Our results indicate that the N-terminal domain of Rep encoded by BSCTV mediates the suppression of RNA silencing and induces VIM5 expression. Thus, our findings contribute to a better understanding of interactions between geminiviral Rep and plant hosts.
Geminiviridae/genetics* ; Nicotiana/metabolism* ; Arabidopsis/metabolism* ; RNA Interference ; Viral Proteins/metabolism* ; Arabidopsis Proteins/metabolism* ; Plants, Genetically Modified/metabolism* ; Protein Domains ; Plant Diseases/virology* ; Methyltransferases/metabolism* ; Ubiquitin-Protein Ligases/metabolism* ; DNA Helicases/genetics*

OBJECTIVES: To investigate the regulatory mechanism of aurora kinase B (AURKB) for promoting malignant phenotype of osteosarcoma cells. METHODS: HA-Vector or HA-AURKB was transfected in 293T cells to identify the molecules interacting with AURKB using immunoprecipitation combined with liquid chromatography-tandem mass spectrometry followed by verification with co-immunoprecipitation and Western blotting. In cultured osteosarcoma cells with lentivirus-mediated RNA interference of AURKB or DHX9 or their overexpression, the changes in cell proliferation, migration, and invasion activities were observed with EDU and Transwell assays. Mechanistic analysis was performed using Co-IP and in vivo ubiquitination experiments to detect the interaction between AURKB and DHX9 and the phosphorylation and ubiquitination levels of DHX9. Western blotting was used to detect the effect of AURKB and DHX9 on activation of nuclear factor-κB (NF-κB) signaling. RESULTS: AURKB was highly expressed in osteosarcoma cell lines, and in osteosarcoma 143B cells, AURKB silencing significantly reduced cell proliferation, migration and invasion abilities. Interactions between AURKB and DHX9 were detected, and they were both highly expressed in osteosarcoma tissues; silencing AURKB reduced the protein expression of DHX9, and AURKB overexpression increased DHX9 phosphorylation. Silencing AURKB did not significantly affect the transcription and translation of DHX9 but accelerated its degradation and ubiquitination. Overexpression of DHX9 effectively reversed the effects of AURKB silencing on IKBα protein and phosphorylated p65, promoted nuclear translocation of p65 to activate the NF-κB signaling pathway, and enhanced the proliferation, migration, and invasion abilities of cultured osteosarcoma cells. CONCLUSIONS AURKB overexpression promotes the malignant phenotype of osteosarcoma cells by activating the NF-κB signaling pathway via regulating DHX9.
Humans ; Osteosarcoma/genetics* ; Cell Proliferation ; NF-kappa B/metabolism* ; Signal Transduction ; Cell Line, Tumor ; Cell Movement ; DEAD-box RNA Helicases/genetics* ; Aurora Kinase B/genetics* ; Phenotype ; Bone Neoplasms/genetics* ; Neoplasm Invasiveness ; Phosphorylation ; Neoplasm Proteins

We knocked out the retinoic acid-inducible gene I (RIG-I) in HEK293 cells via CRISPR/Cas9 to reveal the effects of RIG-I knockout on the key factors in the type I interferon signaling pathway. Three single guide RNAs (sgRNAs) targeting RIG-I were designed, and the recombination vectors were constructed on the basis of the pX459 vector and used to transfect HEK293 cells, which were screened by puromycin subsequently. Furthermore, a mimic of virus, poly I: C, was used to transfect the cells screened out. RIG-I knockout was checked by sequencing, real-time quantitative PCR, Western blotting, and immunofluorescence assay. Meanwhile, the expression levels of key factors of type I interferon signaling pathway such as melanoma differentiation-associated gene 5 (MDA5), interferonβ1 (IFNβ1), and nuclear factor-kappa B p65 [NF-κB(p65)], as well as cell viability, were determined. The results showed that two HEK293 cell lines (S1 and S3) with RIG-I knockout were obtained, which exhibited lower mRNA and protein levels of RIG-I than the wild type HEK293 cells (P < 0.05). The mRNA levels of MDA5 and IFNβ1 in S1 and S3 cells and the protein level of NF-κB(p65) in S3 cells were lower than those in the wild type (P < 0.05). More extranuclear NF-κB(p65) protein was detected in S1 cells than in the wild type after transfection with poly I: C. Plus, the wild-type and S1 cells transfected with poly I: C for 48 h showcased reduced viability (P < 0.05), while S3 cells did not display the reduction in cell viability. In summary, the present study obtained two HEK293 cell lines with RIG-I knockout via CRISPR/Cas9, which provided a stable cell model for exploring the mechanism of type I interferon signaling pathway.
Humans ; HEK293 Cells ; CRISPR-Cas Systems ; DEAD Box Protein 58/metabolism* ; Signal Transduction ; Receptors, Immunologic/metabolism* ; Gene Knockout Techniques ; Transfection ; DEAD-box RNA Helicases/metabolism* ; RNA, Guide, CRISPR-Cas Systems/genetics* ; Interferon-Induced Helicase, IFIH1/metabolism* ; Transcription Factor RelA/metabolism* ; Interferon-beta/metabolism*

Humans ; Carcinogenesis/genetics* ; Gene Expression Regulation, Neoplastic ; Genes, cdc ; Nasopharyngeal Carcinoma/genetics* ; Nasopharyngeal Neoplasms/genetics* ; RNA Helicases/metabolism*

A complete proteomics study characterizing active androgen receptor (AR) complexes in prostate cancer (PCa) cells identified a diversity of protein interactors with tumorigenic annotations, including known RNA splicing factors. Thus, we chose to further investigate the functional role of AR-mediated alternative RNA splicing in PCa disease progression. We selected two AR-interacting RNA splicing factors, Src associated in mitosis of 68 kDa (SAM68) and DEAD (Asp-Glu-Ala-Asp) box helicase 5 (DDX5) to examine their associative roles in AR-dependent alternative RNA splicing. To assess the true physiological role of AR in alternative RNA splicing, we assessed splicing profiles of LNCaP PCa cells using exon microarrays and correlated the results to PCa clinical datasets. As a result, we were able to highlight alternative splicing events of clinical significance. Initial use of exon-mini gene cassettes illustrated hormone-dependent AR-mediated exon-inclusion splicing events with SAM68 or exon-exclusion splicing events with DDX5 overexpression. The physiological significance in PCa was investigated through the application of clinical exon array analysis, where we identified exon-gene sets that were able to delineate aggressive disease progression profiles and predict patient disease-free outcomes independently of pathological clinical criteria. Using a clinical dataset with patients categorized as prostate cancer-specific death (PCSD), these exon gene sets further identified a select group of patients with extremely poor disease-free outcomes. Overall, these results strongly suggest a nonclassical role of AR in mediating robust alternative RNA splicing in PCa. Moreover, AR-mediated alternative spicing contributes to aggressive PCa progression, where we identified a new subtype of lethal PCa defined by AR-dependent alternative splicing.
Humans ; Male ; Alternative Splicing ; Cell Line, Tumor ; DEAD-box RNA Helicases/metabolism* ; Disease Progression ; Gene Expression Regulation, Neoplastic ; Prostatic Neoplasms/pathology* ; Receptors, Androgen/metabolism* ; RNA Splicing Factors/metabolism*

Myelodysplastic syndrome (MDS) are a heterogeneous group of hematological malignancies. Currently, in addition to demethylated chemotherapy and hematopoietic stem cell transplantation, MDS patient-derived mesenchymal stem cells (MDS-MSC) play an important role in understanding the pathogenesis of MDS and related therapeutic targets. For example, abnormal expression of DICER1 gene, abnormalities of PI3K/AKT and Wnt/β-catenin signaling pathways provide new therapeutic targets for MDS. In addition, MDS-MSC is also affected by abnormal microenvironment of the body, such as inflammatory factor S100A9, as well as hypercoagulation and iron overload. In this review, genes, signaling pathways, cytokines, hematopoietic microenvironment, and the effect of therapeutic drugs for MDS-MSC were briefly summarized.
Cytokines/metabolism* ; DEAD-box RNA Helicases/metabolism* ; Hematologic Neoplasms/metabolism* ; Humans ; Mesenchymal Stem Cells ; Myelodysplastic Syndromes/genetics* ; Phosphatidylinositol 3-Kinases/metabolism* ; Ribonuclease III/metabolism* ; Tumor Microenvironment

Up-frameshift 1 (UPF1), as the most critical factor in nonsense-mediated messenger RNA (mRNA) decay (NMD), regulates tumor-associated molecular pathways in many cancers. However, the role of UPF1 in lung adenocarcinoma (LUAD) amino acid metabolism remains largely unknown. In this study, we found that UPF1 was significantly correlated with a portion of amino acid metabolic pathways in LUAD by integrating bioinformatics and metabolomics. We further confirmed that UPF1 knockdown inhibited activating transcription factor 4 (ATF4) and Ser51 phosphorylation of eukaryotic translation initiation factor 2α (eIF2α), the core proteins in amino acid metabolism reprogramming. In addition, UPF1 promotes cell proliferation by increasing the amino-acid levels of LUAD cells, which depends on the function of ATF4. Clinically, UPF1 mRNA expression is abnormal in LUAD tissues, and higher expression of UPF1 and ATF4 was significantly correlated with poor overall survival (OS) in LUAD patients. Our findings reveal that UPF1 is a potential regulator of tumor-associated amino acid metabolism and may be a therapeutic target for LUAD.
Activating Transcription Factor 4/genetics* ; Adenocarcinoma of Lung ; Amino Acids ; Cell Proliferation ; Eukaryotic Initiation Factor-2 ; Humans ; Lung Neoplasms ; RNA Helicases/metabolism* ; RNA, Messenger/metabolism* ; Trans-Activators/metabolism*

OBJECTIVE: To assess the value of m⁷G-lncRNAs in predicting the prognosis and microenvironment of colorectal cancer (CRC). METHODS: We screened m⁷G-lncRNAs from TCGA to construct an m⁷G-lncRNAs risk model using multivariate Cox analysis, which was validated using ROC and C-index curves. Calibration and nomogram were used to predict the prognosis of CRC patients. Point-bar charts and K-M survival curves were used to assess the correlation of risk scores with the patients' clinical staging and prognosis. CIBERSORT and ESTIMATE were used to explore the association between the tumor microenvironment and immune cell infiltration in patients in high and low risk groups and the correlation of risk scores with microsatellite instability, stem cell index and immune checkpoint expression. A protein-protein interaction network was constructed, and the key targets regulated by m⁷G-lncRNAs were identified and validated in paired samples of CRC and adjacent tissues by immunoblotting. RESULTS: We identified a total of 1722 m⁷G-lncRNAs from TCGA database, from which 12 lncRNAs were screened to construct the risk model. The AUCs of the risk model for predicting survival outcomes at 1, 3 and 5 years were 0.727, 0.747 and 0.794, respectively. The AUC of the nomogram for predicting prognosis was 0.794, and the predicted results were consistent with actual survival outcomes of the patients. The patients in the high-risk group showed more advanced tumor stages and a greater likelihood of high microsatellite instability than those in the low-risk group (P < 0.05). The tumor stemness index was negatively correlated with the risk score (r=-0.19; P=7.3e-05). Patients in the high-risk group had higher stromal cell scores (P=0.0028) and higher total scores (P=0.007) with lowered expressions of activated mast cells (r=-0.11; P=0.045) and resting CD4+ T cells (r=-0.14; P=0.01) and increased expressions of most immune checkpoints (P < 0.05). ATXN2 (P= 0.006) and G3BP1 (P=0.007) were identified as the key targets regulated by m⁷G-lncRNAs, and their expressions were both higher in CRC than in adjacent tissues. CONCLUSION The risk model based on 12 m⁷G-lncRNAs has important prognostic value for CRC and can reflect the microenvironment and the efficacy of immunotherapy in the patients.
Biomarkers, Tumor/metabolism* ; Colonic Neoplasms ; DNA Helicases/metabolism* ; Gene Expression Regulation, Neoplastic ; Humans ; Microsatellite Instability ; Poly-ADP-Ribose Binding Proteins/metabolism* ; Prognosis ; RNA Helicases/metabolism* ; RNA Recognition Motif Proteins/metabolism* ; RNA, Long Noncoding/metabolism* ; Tumor Microenvironment

RNA helicases, the largest family of proteins that participate in RNA metabolism, stabilize the intracellular environment through various processes, such as translation and pre-RNA splicing. These proteins are also involved in some diseases, such as cancers and viral diseases. Autophagy, a self-digestive and cytoprotective trafficking process in which superfluous organelles and cellular garbage are degraded to stabilize the internal environment or maintain basic cellular survival, is associated with human diseases. Interestingly, similar to autophagy, RNA helicases play important roles in maintaining cellular homeostasis and are related to many types of diseases. According to recent studies, RNA helicases are closely related to autophagy, participate in regulating autophagy, or serve as a bridge between autophagy and other cellular activities that widely regulate some pathophysiological processes or the development and progression of diseases. Here, we summarize the most recent studies to understand how RNA helicases function as regulatory proteins and determine their association with autophagy in various diseases.
Animals ; Antiviral Agents/pharmacology* ; Autophagy ; Beclin-1/metabolism* ; Carcinogenesis ; Cell Survival ; DEAD Box Protein 58/metabolism* ; Disease Progression ; Gene Expression Regulation ; Homeostasis ; Humans ; Immune System/physiology* ; Neoplasms/metabolism* ; RNA Helicases/metabolism* ; RNA Splicing ; Receptors, Immunologic/metabolism*