Seneca Valley Virus Induces DHX30 Cleavage to Antagonize Its Antiviral Effects.

Seneca Valley virus (SVV) is a new pathogen associated with porcine idiopathic vesicular disease (PIVD) in recent years. However, SVV-host interaction is still unclear. In this study, through LC-MS/MS analysis and coimmunoprecipitation analysis, DHX30 was identified as a 3Cpro-interacting protein. 3Cpro mediated the cleavage of DHX30 at a specific site, which depends on its protease activity. Further study showed that DHX30 was an intrinsic antiviral factor against SVV that was dependent on its helicase activity. DHX30 functioned as a viral-RNA binding protein that inhibited SVV replication at the early stage of viral infection. RIP-seq showed comparatively higher coverage depth at SVV 5'UTR, but the distribution across SVV RNA suggested that the interaction had low specificity. DHX30 expression strongly inhibited double-stranded RNA (dsRNA) production. Interestingly, DHX30 was determined to interact with 3D in an SVV RNA-dependent manner. Thus, DHX30 negatively regulated SVV propagation by blocking viral RNA synthesis, presumably by participating in the viral replication complex. IMPORTANCE DHX30, an RNA helicase, is identified as a 3Cpro-interacting protein regulating Seneca Valley virus (SVV) replication dependent on its helicase activity. DHX30 functioned as a viral-RNA binding protein that inhibited SVV replication at the early stage of virus infection. DHX30 expression strongly inhibited double-stranded RNA (dsRNA) production. In addition, 3Cpro abolished DHX30 antiviral effects by inducing DHX30 cleavage. Thus, DHX30 is an intrinsic antiviral factor that inhibits SVV replication.

DHX30-Associated Neurodevelopmental Disorder with Severe Motor Impairment and Absent Language: First Korean Case in Two Siblings and Literature Review.

DHX30 variants have recently been reported in patients with neurodevelopmental disorders with severe motor impairment and absent language (NEDMIAL). We report the first Korean siblings presenting with NEDMIAL and previously unreported clinical features harboring a rare de novo DHX30 missense variant. The proband was a 10-year-old boy presenting with intellectual disability with severe motor impairment, absent language, facial dysmorphism, strabismus, sleep disturbances, and feeding difficulties. We performed whole-exome sequencing using genomic deoxyribonucleic acid isolated from buccal swabs, which revealed a heterozygous missense variant of DHX30: (c.2344C>T, p.Arg782Trp). Sanger sequencing was conducted for the proband, the affected sister, and each parent. The same variant was confirmed in two siblings but not in their parents, suggesting the possibility of de novo germline mosaicism.

A Novel De Novo Mutation of the DHX30 Gene in a Patient With Neurodevelopmental Disorder, Severe Motor Impairment, and Absent Language (NEDMIAL).

INTRODUCTION:  DExH-Box Helicase 30 (DHX30) is a gene that codes for proteins. It belongs to the class of RNA secondary structure unwinding helicases known as DExH-boxes. There have been numerous reports of pathogenic DHX30 variants. Most mutations, but not all, result in severe phenotypic abnormalities. The most common symptoms are severe motor developmental delay, intellectual disability, sleep disturbances, autism spectrum disorder, seizures, and gait abnormalities. OBJECTIVE: The objectives of reporting this case are: To report a novel mutation giving rise to NEDMIAL and to update the literature regarding the manifestation of the case of a rare condition (NEDMIAL). CASE PRESENTATION:  We report the case of a 12-year-old female who presented with similar complaints of severe motor impairment, seizures, intellectual disability, and absent language and was later diagnosed on Next-Generation Sequencing (NGS) with an autosomal dominant neurodevelopmental disorder (NEDMIAL). CONCLUSION:  We report a case of neurodevelopmental disorder with severe motor impairment and absent language (NEDMIAL) with a De novo novel DHX30 mutation (p.Pro796Leu) detected by whole exome sequence. We suggest upgrading the variant classification of DHX30:p.Pro796Leu to likely pathogenic, according to the evidence found in our patient. To the best of our knowledge, this is the first reported case of this mutation and disorder in the Middle East.

DHX30 Coordinates Cytoplasmic Translation and Mitochondrial Function Contributing to Cancer Cell Survival.

DHX30 was recently implicated in the translation control of mRNAs involved in p53-dependent apoptosis. Here, we show that DHX30 exhibits a more general function by integrating the activities of its cytoplasmic isoform and of the more abundant mitochondrial one. The depletion of both DHX30 isoforms in HCT116 cells leads to constitutive changes in polysome-associated mRNAs, enhancing the translation of mRNAs coding for cytoplasmic ribosomal proteins while reducing the translational efficiency of the nuclear-encoded mitoribosome mRNAs. Furthermore, the depletion of both DHX30 isoforms leads to higher global translation but slower proliferation and lower mitochondrial energy metabolism. Isoform-specific silencing supports a role for cytoplasmic DHX30 in modulating global translation. The impact on translation and proliferation was confirmed in U2OS and MCF7 cells. Exploiting RIP, eCLIP, and gene expression data, we identified fourteen mitoribosome transcripts we propose as direct DHX30 targets that can be used to explore the prognostic value of this mechanism in cancer. We propose that DHX30 contributes to cell homeostasis by coordinating ribosome biogenesis, global translation, and mitochondrial metabolism. Targeting DHX30 could, thus, expose a vulnerability in cancer cells.

Fatal COVID-19 in a Child with Persistence of SARS-CoV-2 Despite Extensive Multidisciplinary Treatment: A Case Report.

Critical Coronavirus disease 2019 (COVID-19) developed in a 7-year-old girl with a history of dystrophy, microcephaly, and central hypothyroidism. Starting with gastrointestinal symptoms, the patient developed severe myocarditis followed by progressive multiple organ failure complicated by Pseudomonas aeruginosa bloodstream infection. Intensive care treatment consisting of invasive ventilation, drainage of pleural effusion, and high catecholamine therapy could not prevent the progression of heart failure, leading to the implantation of venoarterial extracorporeal life support (VA-ECLS) and additional left ventricle support catheter (Impella® pump). Continuous venovenous hemofiltration (CVVH) and extracorporeal hemadsorption therapy (CytoSorb®) were initiated. Whole exome sequencing revealed a mutation of unknown significance in DExH-BOX helicase 30 (DHX30), a gene encoding a RNA helicase. COVID-19 specific antiviral and immunomodulatory treatment did not lead to viral clearance or control of hyperinflammation resulting in the patient's death on extracorporeal life support-(ECLS)-day 20. This fatal case illustrates the potential severity of pediatric COVID-19 and suggests further evaluation of antiviral treatment strategies and vaccination programs for children.

Translation control can shape TP53-dependent cell fate.

The search for mechanisms underlying different cellular responses to the treatment with Nutlin-3, an MDM2 inhibitor that unleashes p53, revealed a translational control mechanism involving the RNA binding proteins PCBP2 and, particularly, DHX30. Sifting through a multi-functional p53-dependent transcriptional output, this translational control can modulate the activation of cell death pathways.

Nutlin-Induced Apoptosis Is Specified by a Translation Program Regulated by PCBP2 and DHX30.

Activation of p53 by the small molecule Nutlin can result in a combination of cell cycle arrest and apoptosis. The relative strength of these events is difficult to predict by classical gene expression analysis, leaving uncertainty as to the therapeutic benefits. In this study, we report a translational control mechanism shaping p53-dependent apoptosis. Using polysome profiling, we establish Nutlin-induced apoptosis to associate with the enhanced translation of mRNAs carrying multiple copies of an identified 3' UTR CG-rich motif mediating p53-dependent death (CGPD-motif). We identify PCBP2 and DHX30 as CGPD-motif interactors. We find that in cells undergoing persistent cell cycle arrest in response to Nutlin, CGPD-motif mRNAs are repressed by the PCBP2-dependent binding of DHX30 to the motif. Upon DHX30 depletion in these cells, the translation of CGPD-motif mRNAs increases, and the response to Nutlin shifts toward apoptosis. Instead, DHX30 inducible overexpression in SJSA1 cells leads to decreased translation of CGPD-motif mRNAs.