Dioscin decreases M2 polarization via inhibiting a positive feedback loop between RBM47 and NF-κB in glioma

BACKGROUND

The role of the glioblastoma (GBM) microenvironment is pivotal in the development of gliomas. Discovering drugs that can traverse the blood-brain barrier and modulate the tumor microenvironment is crucial for the treatment of GBM. Dioscin, a steroidal saponin derived from various kinds of plants and herbs known to penetrate the blood-brain barrier, has shown its powerful anti-tumor activity. However, little is known about its effects on GBM microenvironment.

METHODS

Bioinformatics analysis was conducted to assess the link between GBM patients and their prognosis. Multiple techniques, including RNA sequencing, immunofluorescence staining, Western blot analysis, RNA-immunoprecipitation (RIP) assays, and Chromatin immunoprecipitation (CHIP) analysis were employed to elucidate the mechanism through which Dioscin modulates the immune microenvironment.

RESULTS

Dioscin significantly impaired the polarization of macrophages into the M2 phenotype and enhanced the phagocytic ability of macrophages in vitro and in vivo. A strong correlation between high expression of RBM47 in GBM and a detrimental prognosis for patients was demonstrated. RNA-sequencing analysis revealed an association between RBM47 and the immune response. The inhibition of RBM47 significantly impaired the recruitment and polarization of macrophages into the M2 phenotype and enhanced the phagocytic ability of macrophages. Moreover, RBM47 could stabilize the mRNA of inflammatory genes and enhance the expression of these genes by activating the NF-κB pathway. In addition, NF-κB acts as a transcription factor that enhances the transcriptional activity of RBM47. Notably, we found that Dioscin could significantly inhibit the activation of NF-κB and then downregulate the expression of RBM47 and inflammatory genes protein.

CONCLUSION

Our study reveals that the positive feedback loop between RBM47 and NF-κB could promote immunosuppressive microenvironment in GBM. Dioscin effectively inhibits M2 polarization in GBM by disrupting the positive feedback loop between RBM47 and NF-κB, indicating its potential therapeutic effects in GBM treatment.

A RBM47 and IGF2BP1 mediated circular FNDC3B-FNDC3B mRNA imbalance is involved in the malignant processes of osteosarcoma

BACKGROUND

Circular RNAs (circRNAs) are a class of noncoding RNAs that are involved in the progression of many human cancers. The precise gene locus and the roles of circular RNA from Fibronectin type III domain containing 3B (FNDC3B) in OS and its mechanisms of action have not been fully explored.

MATERIALS AND METHODS

qRT-qPCR assay was used to determine gene expressions. CCK8 Assay, EdU assay, wound-healing assay, transwell invasion assay and in vivo xenograft assay were used to perform functional investigations. RNA-FISH, immunofluorescence, RIP assay, RNA stability analysis were applied in mechanistic studies.

RESULTS

We found that circFNDC3B downregulated and FNDC3B mRNA upregulated in OS, and might be potential biomarkers for indicating disease progression and prognosis of OS patients. CircFNDC3B acted as a tumor suppressor gene to restrain OS progression and FNDC3B functioned as an oncogene to promote OS progression in vitro and in vivo. RNA binding protein RNA binding motif protein 47 (RBM47) could bind to the flanking introns of circFNDC3B to facilitate the generation of circFNDC3B, resulting in the reduction of FNDC3B mRNA and the circFNDC3B-FNDC3B mRNA imbalance. CircFNDC3B also inhibited FNDC3B mRNA expression by reducing its stability via competitively binding to Insulin-like growth-factor-2 mRNA binding protein (IGF2BP1).

CONCLUSION

This study demonstrated that RBM47 and IGF2BP1 mediated circular FNDC3B/FNDC3B mRNA imbalance was involved in the malignant processes of OS.

RNA-Binding Motif Protein RBM47 Promotes Invasiveness of Glioblastoma Through Activation of Epithelial-to-Mesenchymal Transition Program

Background: RNA-binding motif proteins (RBMs) have been widely implicated in the tumorigenesis of multiple human cancers but rarely investigated in glioblastoma (GBM). Methods: The expression level of RBM47 and its correlation with prognosis of GBM were examined using bioinformatics, quantitative reverse transcription PCR, and Western blot analysis. The colony formation assay and Cell Counting Kit-8 assay were used to determine the biological role of RBM47 in GBM. To measure invasiveness we used the wound healing assay and transwell assay. The regulatory relationship between RBM47 and the epithelial-to-mesenchymal transition (EMT) was examined by Western blot analysis and bioinformatic analysis. Results: Through integrative analysis of clinical proteomic and genomic tumor datasets, we found that RBM47 is significantly upregulated in GBM mesenchymal subtype, and its high expression is correlated with poor prognosis. In in vitro biological experiments, we observed a significant inhibitory effect of RBM47 knockdown on colony formation and cell growth using GBM cell lines. Conversely, overexpression of RBM47 restored and accelerated these processes. Moreover, in vitro, wound healing assays demonstrated the role of RBM46 in promoting and cell migration and invasion. Mechanistically, RBM47 enhances invasive capacity through the activation of the EMT program. In RBM47-knockdown cells, the expression levels of Vimentin and CD44 were suppressed, and the level of E-cadherin was increased. Conclusions: Taken together our results demonstrate the tumor promoting characteristics of RBM46 and suggest that it could be used both as a therapeutic target and prognostically.

LncRNA IDH1-AS1 sponges miR-518c-5p to suppress proliferation of epithelial ovarian cancer cell by targeting RMB47

Long noncoding RNA (lncRNA) IDH1 antisense RNA 1 ( IDH1-AS1) is involved in the progression of multiple cancers, but its role in epithelial ovarian cancer (EOC) is unknown. Therefore, we investigated the expression levels of IDH1-AS1 in EOC cells and normal ovarian epithelial cells by quantitative real-time PCR (qPCR). We first evaluated the effects of IDH1-AS1 on the proliferation, migration, and invasion of EOC cells through cell counting kit-8, colony formation, EdU, transwell, wound-healing, and xenograft assays. We then explored the downstream targets of IDH1-AS1 and verified the results by a dual-luciferase reporter, qPCR, rescue experiments, and Western blotting. We found that the expression levels of IDH1-AS1 were lower in EOC cells than in normal ovarian epithelial cells. High IDH1-AS1 expression of EOC patients from the Gene Expression Profiling Interactive Analysis database indicated a favorable prognosis, because IDH1-AS1 inhibited cell proliferation and xenograft tumor growth of EOC. IDH1-AS1 sponged miR-518c-5p whose overexpression promoted EOC cell proliferation. The miR-518c-5p mimic also reversed the proliferation-inhibiting effect induced by IDH1-AS1 overexpression. Furthermore, we found that RNA binding motif protein 47 (RBM47) was the downstream target of miR-518c-5p, that upregulation of RBM47 inhibited EOC cell proliferation, and that RBM47 overexpressing plasmid counteracted the proliferation-promoting effect caused by the IDH1-AS1 knockdown. Taken together, IDH1-AS1 may suppress EOC cell proliferation and tumor growth via the miR-518c-5p/RBM47 axis.

Changes in RBM47 expression based on the timing of melatonin administration and its effects on Nrf2 activity in the hippocampus

Melatonin is an endogenous indoleamine that plays a significant role in various physiological processes, including the sleep-wake cycle, anxiety, immunity, and circadian rhythms. However, it is important to clarify that melatonin does not directly control circadian rhythms. Circadian rhythms are primarily synchronized by light, which acts on the suprachiasmatic nucleus (SCN) and subsequently regulates melatonin production. This light-mediated synchronization of circadian rhythms is essential for maintaining the alignment of the body with the light-dark cycle. In this study, we investigated the efficacy of melatonin administration during different times of the day or night and explored its neuroprotective effects. Furthermore, we aimed to apply these findings to rodent models of dementia, aging, and neuro-inflammation for potential therapeutic applications. Our study uncovered novel evidence suggesting the involvement of RNA-binding motif protein (RBM)-47 and Nrf2 in the signaling pathways associated with melatonin administration during both day and night. We examined the role of RBM47 in Nrf2 activity through siRNA or CRISPR-mediated knockdown experiments using hippocampal neuronal cells and lentivirus injections in mice. In 5xFAD/aging/neuroinflammatory mouse models, antioxidant effects were enhanced when melatonin was administered during the day compared to nighttime administration. Furthermore, mRNA analysis and molecular biology experiments revealed the differential expression of RBM47 depending on the timing of melatonin administration. These findings suggest that a decrease in RBM47 expression may improve the antioxidant defense system in the hippocampus. Consequently, administering melatonin during the day rather than at night may present a plausible therapeutic strategy as an antioxidant.

Saponin from Platycodi radix inactivates PI3K/AKT signaling pathway to hinder colorectal cancer cell proliferation, invasion, and migration through miR-181c/d-5p/RBM47

Colorectal cancer (CRC) is the third frequent cancer and second leading reason of cancer-related mortality all over the globe. Saponins from Platycodi radix (SPR) and microRNAs (miRNAs) have been reported to regulate CRC cell progression. Real-time quantitative polymerase chain reaction (RT-qPCR) detected miR-181c-5p, miR-181d-5p, and RBM47 expression level. Cell counting kit-8 (CCK-8), 5-ethynyl-20-deoxyuridine (EdU), colony formation, transwell, and wound healing assays validated that miR-181c-5p and miR-181d-5p promote CRC cell proliferation, migration and invasion and SPR exerts opposite effects. Cignal Finder Reporter Array and western blot proved that the activity of PI3K/AKT pathway was decreased by RBM47 overexpression. RNA pulldown, luciferase reporter, and RNA-binding protein immunoprecipitation (RIP) assays proved the interaction between miR-181c/d-5p and RBM47, and RBM47 and PTEN. Rescue experiments were carried out to validate that RBM47 reverses the influence of miR-181c/d-5p on the progression of CRC cells. The stability of PTEN was probed by real-time quantitative polymerase chain reaction in CRC cells treated with Actinomycin D (Act D). To be concluded, SPR inactivates PI3K/AKT signaling pathway to suppress CRC cell proliferation, invasion, and migration via miR-181c/d-5p/RBM47. Elucidating the mechanisms of SPR underlying CRC may offer novel insight into CRC treatment.

Whole-exome sequencing identifies novel protein-altering variants associated with serum apolipoprotein and lipid concentrations

BACKGROUND

Dyslipidemia is a major risk factor for cardiovascular disease, and diabetes impacts the lipid metabolism through multiple pathways. In addition to the standard lipid measurements, apolipoprotein concentrations provide added awareness of the burden of circulating lipoproteins. While common genetic variants modestly affect the serum lipid concentrations, rare genetic mutations can cause monogenic forms of hypercholesterolemia and other genetic disorders of lipid metabolism. We aimed to identify low-frequency protein-altering variants (PAVs) affecting lipoprotein and lipid traits.

METHODS

We analyzed whole-exome (WES) and whole-genome sequencing (WGS) data of 481 and 474 individuals with type 1 diabetes, respectively. The phenotypic data consisted of 79 serum lipid and apolipoprotein phenotypes obtained with clinical laboratory measurements and nuclear magnetic resonance spectroscopy.

RESULTS

The single-variant analysis identified an association between the LIPC p.Thr405Met (rs113298164) and serum apolipoprotein A1 concentrations (p=7.8×10^-8). The burden of PAVs was significantly associated with lipid phenotypes in LIPC, RBM47, TRMT5, GTF3C5, MARCHF10, and RYR3 (p<2.9×10^-6). The RBM47 gene is required for apolipoprotein B post-translational modifications, and in our data, the association between RBM47 and apolipoprotein C-III concentrations was due to a rare 21 base pair p.Ala496-Ala502 deletion; in replication, the burden of rare deleterious variants in RBM47 was associated with lower triglyceride concentrations in WES of >170,000 individuals from multiple ancestries (p=0.0013). Two PAVs in GTF3C5 were highly enriched in the Finnish population and associated with cardiovascular phenotypes in the general population. In the previously known APOB gene, we identified novel associations at two protein-truncating variants resulting in lower serum non-HDL cholesterol (p=4.8×10^-4), apolipoprotein B (p=5.6×10^-4), and LDL cholesterol (p=9.5×10^-4) concentrations.

CONCLUSIONS

We identified lipid and apolipoprotein-associated variants in the previously known LIPC and APOB genes, as well as PAVs in GTF3C5 associated with LDLC, and in RBM47 associated with apolipoprotein C-III concentrations, implicated as an independent CVD risk factor. Identification of rare loss-of-function variants has previously revealed genes that can be targeted to prevent CVD, such as the LDL cholesterol-lowering loss-of-function variants in the PCSK9 gene. Thus, this study suggests novel putative therapeutic targets for the prevention of CVD.

Identification of key candidate genes for wing length-related traits by whole-genome resequencing in 772 geese

1. A total of 772, 420-day-old Xingguo gray geese (XGG) were sequenced using a low-depth (~1×) whole-genome resequencing strategy to reveal the genetic mechanism of wing length-related traits by genome-wide association analysis (GWAS).2. The results showed that 119 SNPs had genome-wide significance for wing length in five regions of chromosome 4, of which the most significant locus (P=7.95E-11) was located upstream of RBM47 and explained 7.3% of phenotypic variation.3. A total of 219 SNPs located on chromosome 4 that were associated with 2-joint-wing length, of which four SNPs reached the genome-wide significant level. However, for the length of 1-joint-wing and primary feather, we did not detect any associated locus.4. Six promising candidate genes, RBM47, SLAIN2, GRXCR1, SLC10A4, APBB2 and NSUN7 on chromosome 4, may play an important role in the growth and development of feathers, muscles and bones.

RNA-binding motif protein RBM47 promotes tumorigenesis in nasopharyngeal carcinoma through multiple pathways

RNA binding motif proteins (RBMs) have been widely implicated in the tumorigenesis of multiple human cancers but scarcely studied in nasopharyngeal carcinoma (NPC). Here, we compare the mRNA levels of 29 RBMs between 87 NPC and 10 control samples. We find that RBM47 is frequently upregulated in NPC specimens, and its high expression is associated with the poor prognosis of patients with NPC. Biological experiments show that RBM47 plays an oncogenic role in NPC cells. Mechanically, RBM47 binds to the promoter and regulates the transcription of BCAT1, and its overexpression partially rescues the inhibitory effects of RBM47-knockdown on NPC cells. Moreover, transcriptome analysis reveals that RBM47 regulates alternative splicing of pre-mRNA, including those cancer-related, to a large extent in NPC cells. Furthermore, RBM47 binds to hnRNPM and cooperatively regulates multiple splicing events in NPC cells. In addition, we find that knockdown of hnRNPM inhibits proliferation and migration of NPC cells. Our study, taken together, shows that RBM47 promotes the progression of NPC through multiple pathways, acting as a transcriptional factor and a modulator of alternative splicing in cooperation with hnRNPM. Our study also highlights that RBM47 and hnRNPM could be prognostic factors and potential therapeutic targets for NPC.

The RNA-binding protein RBM47 inhibits non-small cell lung carcinoma metastasis through modulation of AXIN1 mRNA stability and Wnt/β-catentin signaling

BACKGROUND

Non-small-cell lung cancer (NSCLC) remains a highly prevalent and deadly form of cancer, with efforts to better understand the molecular basis of the progression of this disease being essential to its effective treatment. Several recent studies have highlighted the ability of RNA-binding proteins (RBPs) to regulate a wide range of cellular processes in both healthy and pathogenic contexts. Among these RBPs, RNA binding motif protein 47 (RBM47) has recently been identified as a tumor suppressor in both breast and colon cancers, whereas its role in NSCLC is poorly understood.

METHODS

RBM47 expression in NSCLC samples was evaluated by RT-PCR, western blotting and immunohistochemistry analysis. Molecular and cellular techniques including lentiviral vector-mediated knockdown were used to elucidate the functions and mechanisms of RBM47.

RESULTS

This study sought to analyze the expression and role of RBM47 in NSCLC. In the present study, we observed reduced levels of RBM47 expression in NSCLC, with these reductions corresponding to a poorer prognosis and more advanced disease including a higher TNM stage (p = 0.022), a higher likelihood of tumor thrombus (p = 0.001), and pleural invasion (p = 0.033). Through functional analyses in vitro and in vivo, we further demonstrated that these RBP was able to disrupt the proliferation, migration, and invasion of NSCLC cells. At a molecular level, we determined that RBM47 was able to bind the AXIN1 mRNA, stabilizing it and thereby enhancing the consequent suppression of Wnt/β-catentin signaling.

CONCLUSION

Together our findings reveal that RBM47 targets AXIN1 in order to disrupt Wnt/β-catenin signaling in NSCLC and thereby disrupting tumor progression. These results thus offer new insights into the molecular biology of NSCLC, and suggest that RBM47 may also have value as a prognostic biomarker and/or therapeutic target in NSCLC patients.

Apobec1 complementation factor (A1CF) and RBM47 interact in tissue-specific regulation of C to U RNA editing in mouse intestine and liver

Mammalian C to U RNA is mediated by APOBEC1, the catalytic deaminase, together with RNA binding cofactors (including A1CF and RBM47) whose relative physiological requirements are unresolved. Although A1CF complements APOBEC1 for in vitro RNA editing, A1cf^-/- mice exhibited no change in apolipoproteinB (apoB) RNA editing, while Rbm47 mutant mice exhibited impaired intestinal RNA editing of apoB as well as other targets. Here we examined the role of A1CF and RBM47 in adult mouse liver and intestine, following deletion of either one or both gene products and also following forced (liver or intestinal) transgenic A1CF expression. There were minimal changes in hepatic and intestinal apoB RNA editing in A1cf^-/- mice and no changes in either liver- or intestine-specific A1CF transgenic mice. Rbm47 liver-specific knockout (Rbm47^LKO ) mice demonstrated reduced editing in a subset (11 of 20) of RNA targets, including apoB. By contrast, apoB RNA editing was virtually eliminated (<6% activity) in intestine-specific (Rbm47^IKO ) mice with only five of 53 targets exhibiting C-to-U RNA editing. Double knockout of A1cf and Rbm47 in liver (AR^LKO ) eliminated apoB RNA editing and reduced editing in the majority of other targets, with no changes following adenoviral APOBEC1 administration. Intestinal double knockout mice (AR^IKO ) demonstrated further reduced editing (<10% activity) in four of five of the residual APOBEC1 targets identified in AR^IKO mice. These data suggest that A1CF and RBM47 each function independently, yet interact in a tissue-specific manner, to regulate the activity and site selection of APOBEC1 dependent C-to-U RNA editing.

Re-editing the paradigm of Cytidine (C) to Uridine (U) RNA editing

Cytidine (C) to Uridine (U) RNA editing is a post-trancriptional modification that until recently was known to only affect Apolipoprotein b (Apob) RNA and minimally require 2 components of the C to U editosome, the deaminase APOBEC1 and the RNA-binding protein A1CF. Our latest work has identified a novel RNA-binding protein, RBM47, as a core component of the editosome, which can substitute A1CF for the editing of ApoB mRNA. In addition, new RNA species that are subjected to C to U editing have been identified. Here, we highlight these recent discoveries and discuss how they change our view of the composition of the C to U editing machinery and expand our knowledge of the functional attributes of C to U RNA editing.

C to U RNA editing mediated by APOBEC1 requires RNA-binding protein RBM47

Cytidine (C) to Uridine (U) RNA editing is a post-transcriptional modification that is accomplished by the deaminase APOBEC1 and its partnership with the RNA-binding protein A1CF. We identify and characterise here a novel RNA-binding protein, RBM47, that interacts with APOBEC1 and A1CF and is expressed in tissues where C to U RNA editing occurs. RBM47 can substitute for A1CF and is necessary and sufficient for APOBEC1-mediated editing in vitro. Editing is further impaired in Rbm47-deficient mutant mice. These findings suggest that RBM47 and APOBEC1 constitute the basic machinery for C to U RNA editing.