Dhx33 promotes B-cell growth and proliferation by controlling activation-induced rRNA upregulation

Finding a needle in a haystack: functional screening for novel targets in cancer immunology and immunotherapies

Genome-wide functional genetic screening has been widely used in the biomedicine field, which makes it possible to find a needle in a haystack at the genetic level. In cancer research, gene mutations are closely related to tumor development, metastasis, and recurrence, and the use of state-of-the-art powerful screening technologies, such as clustered regularly interspaced short palindromic repeat (CRISPR), to search for the most critical genes or coding products provides us with a new possibility to further refine the cancer mapping and provide new possibilities for the treatment of cancer patients. The use of CRISPR screening for the most critical genes or coding products has further refined the cancer atlas and provided new possibilities for the treatment of cancer patients. Immunotherapy, as a highly promising cancer treatment method, has been widely validated in the clinic, but it could only meet the needs of a small proportion of cancer patients. Finding new immunotherapy targets is the key to the future of tumor immunotherapy. Here, we revisit the application of functional screening in cancer immunology from different perspectives, from the selection of diverse in vitro and in vivo screening models to the screening of potential immune checkpoints and potentiating genes for CAR-T cells. The data will offer fresh therapeutic clues for cancer patients.

Critical and differential roles of eIF4A1 and eIF4A2 in B-cell development and function

Eukaryotic initiation factor 4 A (eIF4A) plays critical roles during translation initiation of cellular mRNAs by forming the cap-binding eIF4F complex, recruiting the 40S small ribosome subunit, and scanning the 5' untranslated region (5' UTR) for the start codon. eIF4A1 and eIF4A2, two isoforms of eIF4A, are highly conserved and exchange freely within eIF4F complexes. The understanding of their biological and molecular functions remains incomplete if not fragmentary. In this study, we showed that eIF4A1 and eIF4A2 exhibit different expression patterns during B-cell development and activation. Mouse genetic analyses showed that they play critical but differential roles during B-cell development and humoral immune responses. While eIF4A1 controls global protein synthesis, eIF4A2 regulates the biogenesis of 18S ribosomal RNA and the 40S ribosome subunit. This study demonstrates the distinct cellular and molecular functions of eIF4A1 and eIF4A2 and reveals a new role of eIF4A2 in controlling 40S ribosome biogenesis.

DHX34 as a promising biomarker for prognosis, immunotherapy and chemotherapy in Pan-Cancer: A Comprehensive Analysis and Experimental Validation

Background: As a member of the DExD/H-box RNA helicase family, DHX34 has demonstrated a significant correlation with the development of multiple disorders. Nevertheless, a comprehensive investigation between DHX34 and pan-cancer remains unexplored. Methods: We analyzed the value of DHX34 in pan-cancer based on some databases, such as The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and The Human Protein Atlas (HPA) by use the R language as well as some online analysis tools, including STRING, TISIDB, TISCH2. And based on our samples we performed Western blot (WB), qPCR and immunohistochemical staining (IHC) experiments. Results: DHX34 was highly expressed in most tumors, including Liver Hepatocellular Carcinoma (LIHC), compared to corresponding normal tissues. Among cervical cancers, DHX34 mutation frequency was the highest. Intriguingly, a positive correlation was observed between DHX34 expression and Mutational Burden (TMB) across 12 tumor types, and Microsatellite Instability (MSI) across 10 tumor types. Remarkably, DHX34 exhibited a favorable diagnostic value in a multitude of tumors. High expression of DHX34 is associated with poor prognosis in tumors such as adrenocortical carcinoma (ACC), renal papillary cell carcinoma (KIRP), low-grade glioma (LGG), and LIHC. Correlation analysis indicated that DHX34 expression correlated with clinicopathological features in a variety of tumors. The Protein-Protein Interaction (PPI) network and GSCALite database suggested that DHX34 and its ten co-expression genes might promote cancer progression by regulating the cell cycle. Gene Set Enrichment Analysis (GSEA) results further showed that DHX34 was positively correlated with pathways such as cell cycle, mitosis, and gene transcription regulation. The TISIDB database showed that DHX34 expression was closely associated with immune infiltration. Based on the TISCH2 database, we found that DHX34 was expressed in a number of immune cells, with relatively high expression in monocyte macrophages in LIHC. Conclusions: In summary, our study found that DHX34 is highly expressed in pan-cancer and has diagnostic and prognostic value. Targeting DHX34 may improve the therapeutic efficacy of immunotherapy and chemotherapy in a multitude of tumors.

CX-5461 ameliorates disease in lupus-prone mice by triggering B-cell ferroptosis via p53-SLC7A11-ALOX12 pathway

CX-5461, a first-in-class compound, is widely recognized as a selective inhibitor of RNA polymerase I. Recently, it has been reported to possess novel immunosuppressive properties with significant therapeutic effects in transplantation immune rejection. However, the potential use of CX-5461 for Systemic Lupus Erythematosus (SLE) treatment remains unknown. In this study, we elucidated the mechanism underlying the therapeutic efficacy of CX-5461 in lupus. Our findings demonstrated that CX-5461 selectively targets B cells and effectively reduces the proportions of B cells, germinal center B cells, and plasma cells in MRL/MPJ-Faslpr and Resiquimod (R848)-induced lupus mice. Molecular studies revealed that CX-5461 modulates CD36-Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4)-mediated glycerolipid metabolism in B cells, triggering ferroptosis through the p53- Solute Carrier Family 7 Member 11 (SLC7A11)- Arachidonate 12-Lipoxygenase (ALOX12) pathway, thereby decreasing IgG and Anti-Double-Stranded Deoxyribonucleic Acid (dsDNA) antibody levels and attenuating lupus. Collectively, these results suggest that CX-5461 holds promise as an effective candidate for targeted therapy against lupus.

Housekeeping U1 snRNA facilitates antiviral innate immunity by promoting TRIM25-mediated RIG-I activation

U1 small nuclear RNA (snRNA) is an abundant and evolutionarily conserved 164-nucleotide RNA species that functions in pre-mRNA splicing, and it is considered to be a housekeeping non-coding RNA. However, the role of U1 snRNA in regulating host antiviral immunity remains largely unexplored. Here, we find that RNVU1-18, a U1 pseudogene, is significantly upregulated in the host infected with RNA viruses, including influenza and respiratory syncytial virus. Overexpression of U1 snRNA protects cells against RNA viruses, while knockdown of U1 snRNA leads to more viral burden in vitro and in vivo. Knockout of RNVU1-18 is sufficient to impair the type I interferon-dependent antiviral innate immunity. U1 snRNA is required to fully activate the retinoic acid-inducible gene I (RIG-I)-dependent antiviral signaling, since it interacts with tripartite motif 25 (TRIM25) and enhances the RIG-I-TRIM25 interaction to trigger K63-linked ubiquitination of RIG-I. Our study reveals the important role of housekeeping U1 snRNA in regulating host antiviral innate immunity and restricting RNA virus infection.