Phase Ib study of PRT543, an oral protein arginine methyltransferase 5 (PRMT5) inhibitor, in patients with advanced splicing factor-mutant myeloid malignancies
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The potential impact of RNA splicing abnormalities on immune regulation in endometrial cancer
RNA splicing controls the post-transcriptional level of gene expression, allowing for the synthesis of many transcripts with various configurations and roles. Variations in RNA splicing regulatory factors, including splicing factors, signaling pathways, epigenetic modifications, and environmental factors, are typically the origin of tumor-associated splicing anomalies. Furthermore, thorough literature assessments on the intricate connection between tumor-related splicing dysregulation and tumor immunity are currently lacking. Therefore, we also thoroughly discuss putative targets associated with RNA splicing in endometrial cancer (EC) and the possible impacts of aberrant RNA splicing on the immune control of tumor cells and tumor microenvironment (TME), which contributes to enhancing the utilization of immunotherapy in the management of EC and offers an alternative viewpoint for the exploration of cancer therapies and plausible prognostic indicators.
Clinical practice recommendations for the diagnosis and management of X-linked hypophosphataemia
X-linked hypophosphataemia (XLH) is a rare metabolic bone disorder caused by pathogenic variants in the PHEX gene, which is predominantly expressed in osteoblasts, osteocytes and odontoblasts. XLH is characterized by increased synthesis of the bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23), which results in renal phosphate wasting with consecutive hypophosphataemia, rickets, osteomalacia, disproportionate short stature, oral manifestations, pseudofractures, craniosynostosis, enthesopathies and osteoarthritis. Patients with XLH should be provided with multidisciplinary care organized by a metabolic bone expert. Historically, these patients were treated with frequent doses of oral phosphate supplements and active vitamin D, which was of limited efficiency and associated with adverse effects. However, the management of XLH has evolved in the past few years owing to the availability of burosumab, a fully humanized monoclonal antibody that neutralizes circulating FGF23. Here, we provide updated clinical practice recommendations for the diagnosis and management of XLH to improve outcomes and quality of life in these patients.
The contribution of genetic determinants of blood gene expression and splicing to molecular phenotypes and health outcomes
The biological mechanisms through which most nonprotein-coding genetic variants affect disease risk are unknown. To investigate gene-regulatory mechanisms, we mapped blood gene expression and splicing quantitative trait loci (QTLs) through bulk RNA sequencing in 4,732 participants and integrated protein, metabolite and lipid data from the same individuals. We identified cis-QTLs for the expression of 17,233 genes and 29,514 splicing events (in 6,853 genes). Colocalization analyses revealed 3,430 proteomic and metabolomic traits with a shared association signal with either gene expression or splicing. We quantified the relative contribution of the genetic effects at loci with shared etiology, observing 222 molecular phenotypes significantly mediated by gene expression or splicing. We uncovered gene-regulatory mechanisms at disease loci with therapeutic implications, such as WARS1 in hypertension, IL7R in dermatitis and IFNAR2 in COVID-19. Our study provides an open-access resource on the shared genetic etiology across transcriptional phenotypes, molecular traits and health outcomes in humans (https://IntervalRNA.org.uk).
Characterization of the landscape of the intratumoral microbiota reveals that Streptococcus anginosus increases the risk of gastric cancer initiation and progression
As a critical component of the tumour immune microenvironment (TIME), the resident microbiota promotes tumorigenesis across a variety of cancer types. Here, we integrated multiple types of omics data, including microbiome, transcriptome, and metabolome data, to investigate the functional role of intratumoral bacteria in gastric cancer (GC). The microbiome was used to categorize GC samples into six subtypes, and patients with a high abundance of Streptococcus or Pseudomonas had a markedly worse prognosis. Further assays revealed that Streptococcus anginosus (SA) promoted tumour cell proliferation and metastasis while suppressing the differentiation and infiltration of CD8+ T cells. However, antibiotic treatment significantly suppressed tumorigenesis in SA+ mice in vivo. We further demonstrated that the SA arginine pathway increased the abundance of ornithine, which may be a major contributor to reshaping of the TIME. Our findings demonstrated that SA, a novel risk factor, plays significant roles in the initiation and progression of GC, suggesting that SA might be a promising target for the diagnosis and treatment of GC.
Structural insights into spliceosome fidelity: DHX35–GPATCH1- mediated rejection of aberrant splicing substrates
The spliceosome, a highly dynamic macromolecular assembly, catalyzes the precise removal of introns from pre-mRNAs. Recent studies have provided comprehensive structural insights into the step-wise assembly, catalytic splicing and final disassembly of the spliceosome. However, the molecular details of how the spliceosome recognizes and rejects suboptimal splicing substrates remained unclear. Here, we show cryo-electron microscopy structures of spliceosomal quality control complexes from a thermophilic eukaryote, Chaetomium thermophilum. The spliceosomes, henceforth termed B*Q, are stalled at a catalytically activated state but prior to the first splicing reaction due to an aberrant 5’ splice site conformation. This state is recognized by G-patch protein GPATCH1, which is docked onto PRP8-EN and -RH domains and has recruited the cognate DHX35 helicase to its U2 snRNA substrate. In B*Q, DHX35 has dissociated the U2/branch site helix, while the disassembly helicase DHX15 is docked close to its U6 RNA 3’-end substrate. Our work thus provides mechanistic insights into the concerted action of two spliceosomal helicases in maintaining splicing fidelity by priming spliceosomes that are bound to aberrant splice substrates for disassembly.
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