Small nucleolar RNA host gene 8: A rising star in the targets for cancer therapy

LncRNA SNHG8 regulates the migration and angiogenesis of pHUVECs induced by high glucose via the TRPM7/ERK1/2 signaling axis

This study aimed to evaluate the regulatory effect and molecular mechanism of long noncoding RNA small nucleolus RNA host gene 8 (LncRNA SNHG8) in the migration and angiogenesis of primary human umbilical vein endothelial cells (pHUVECs) under high-glucose (HG) conditions. The HG-induced endothelial injury model was established in vitro.The cell model of silencing SNHG8, overexpressing SNHG8, and silencing TRPM7 was established by transfecting SNHG8-siRNA, SNHG8 plasmid and TRPM7-siRNA into cells with liposomes.The SNHG8 level was determined through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression levels of transient receptor potential melastatin 7 (TRPM7), endothelial nitric oxide synthase (eNOS), p-eNOS, extracellular signal-regulated kinase 1/2(ERK1/2), and p-ERK1/2 were assessed through western blot. Nitric oxide (NO) levels were measured with DAF-FM. pHUVEC migration was examined through wound healing and Transwell assay, and pHUVEC angiogenesis was observed through a tube formation assay. Results showed that HG promoted the expression of lncRNA SNHG8 and TRPM7 and decreased the ratio of p-eNOS/eNOS and p-ERK1/2/ERK1/2 in pHUVECs . NO production, migration , and angiogenesis were inhibited in pHUVECs under HG conditions. Silencing lncRNA SNHG8 and TRPM7 could significantly reverse the HG-induced decrease in eNOS activation, NO production , migration, and angiogenesis . SNHG8 and U0126 (ERK pathway inhibitor) overexpression enhanced the HG effects, whereas using U0126 did not affect the TRPM7 expression. In conclusion, lncRNA SNHG8 participates in HG-induced endothelial cell injury and likely regulates NO production, migration, and angiogenesis of pHUVECs via the TRPM7/ERK1/2 signaling axis.

Long non-coding RNA SNHG8 drives stress granule formation in tauopathies

Tauopathies are a heterogenous group of neurodegenerative disorders characterized by tau aggregation in the brain. In a subset of tauopathies, rare mutations in the MAPT gene, which encodes the tau protein, are sufficient to cause disease; however, the events downstream of MAPT mutations are poorly understood. Here, we investigate the role of long non-coding RNAs (lncRNAs), transcripts >200 nucleotides with low/no coding potential that regulate transcription and translation, and their role in tauopathy. Using stem cell derived neurons from patients carrying a MAPT p.P301L, IVS10 + 16, or p.R406W mutation and CRISPR-corrected isogenic controls, we identified transcriptomic changes that occur as a function of the MAPT mutant allele. We identified 15 lncRNAs that were commonly differentially expressed across the three MAPT mutations. The commonly differentially expressed lncRNAs interact with RNA-binding proteins that regulate stress granule formation. Among these lncRNAs, SNHG8 was significantly reduced in a mouse model of tauopathy and in FTLD-tau, progressive supranuclear palsy, and Alzheimer's disease brains. We show that SNHG8 interacts with tau and stress granule-associated RNA-binding protein TIA1. Overexpression of mutant tau in vitro is sufficient to reduce SNHG8 expression and induce stress granule formation. Rescuing SNHG8 expression leads to reduced stress granule formation and reduced TIA1 levels in immortalized cells and in MAPT mutant neurons, suggesting that dysregulation of this non-coding RNA is a causal factor driving stress granule formation via TIA1 in tauopathies.

Long non-coding RNA SNHG8 drives stress granule formation in tauopathies

Tauopathies are a heterogenous group of neurodegenerative disorders characterized by tau aggregation in the brain. In a subset of tauopathies, rare mutations in the MAPT gene, which encodes the tau protein, are sufficient to cause disease; however, the events downstream of MAPT mutations are poorly understood. Here, we investigate the role of long non-coding RNAs (lncRNAs), transcripts >200 nucleotides with low/no coding potential that regulate transcription and translation, and their role in tauopathy. Using stem cell derived neurons from patients carrying a MAPT p.P301L, IVS10+16, or p.R406W mutation, and CRISPR-corrected isogenic controls, we identified transcriptomic changes that occur as a function of the MAPT mutant allele. We identified 15 lncRNAs that were commonly differentially expressed across the three MAPT mutations. The commonly differentially expressed lncRNAs interact with RNA-binding proteins that regulate stress granule formation. Among these lncRNAs, SNHG8 was significantly reduced in a mouse model of tauopathy and in FTLD-tau, progressive supranuclear palsy, and Alzheimer’s disease brains. We show that SNHG8 interacts with tau and stress granule-associated RNA-binding protein TIA1. Overexpression of mutant tau in vitro is sufficient to reduce SNHG8 expression and induce stress granule formation. Rescuing SNHG8 expression leads to reduced stress granule formation and reduced TIA1 levels, suggesting that dysregulation of this non-coding RNA is a causal factor driving stress granule formation via TIA1 in tauopathies.

Epithelial cells-enriched lncRNA SNHG8 regulates chromatin condensation by binding to Histone H1s

Linker histone H1 proteins contain many variants in mammalian and can stabilize the condensed state of chromatin by binding to nucleosomes and promoting a more inaccessible structure of DNA. However, it is poorly understood how the binding of histone H1s to chromatin DNA is regulated. Screened as one of a collection of epithelial cells-enriched long non-coding RNAs (lncRNAs), here we found that small nucleolar RNA host gene 8 (SNHG8) is a chromatin-localized lncRNA and presents strong interaction and phase separation with histone H1 variants. Moreover, SNHG8 presents stronger ability to bind H1s than linker DNA, and outcompetes linker DNA for H1 binding. Consequently, loss of SNHG8 increases the amount of H1s that bind to chromatin, promotes chromatin condensation, and induces an epithelial differentiation-associated gene expression pattern. Collectively, our results propose that the highly abundant SNHG8 in epithelial cells keeps histone H1 variants out of nucleosome and its loss contributes to epithelial cell differentiation.

Cuproptosis-Associated lncRNA Establishes New Prognostic Profile and Predicts Immunotherapy Response in Clear Cell Renal Cell Carcinoma

Background: Clear cell renal cell carcinoma (ccRCC) accounts for 80% of all kidney cancers and has a poor prognosis. Recent studies have shown that copper-dependent, regulated cell death differs from previously known death mechanisms (apoptosis, ferroptosis, and necroptosis) and is dependent on mitochondrial respiration (Tsvetkov et al., Science, 2022, 375 (6586), 1254–1261). Studies also suggested that targeting cuproptosis may be a novel therapeutic strategy for cancer therapy. In ccRCC, both cuproptosis and lncRNA were critical, but the mechanisms were not fully understood. The aim of our study was to construct a prognostic profile based on cuproptosis-associated lncRNAs to predict the prognosis of ccRCC and to study the immune profile of clear cell renal cell carcinoma (ccRCC).

Methods: We downloaded the transcriptional profile and clinical information of ccRCC from The Cancer Genome Atlas (TCGA). Co-expression network analysis, Cox regression method, and least absolute shrinkage and selection operator (LASSO) method were used to identify cuproptosis-associated lncRNAs and to construct a risk prognostic model. In addition, the predictive performance of the model was validated and recognized by an integrated approach. We then also constructed a nomogram to predict the prognosis of ccRCC patients. Differences in biological function were investigated by GO, KEGG, and immunoassay. Immunotherapy response was measured using tumor mutational burden (TMB) and tumor immune dysfunction and rejection (TIDE) scores.

Results: We constructed a panel of 10 cuproptosis-associated lncRNAs (HHLA3, H1-10-AS1, PICSAR, LINC02027, SNHG15, SNHG8, LINC00471, EIF1B-AS1, LINC02154, and MINCR) to construct a prognostic prediction model. The Kaplan–Meier and ROC curves showed that the feature had acceptable predictive validity in the TCGA training, test, and complete groups. The cuproptosis-associated lncRNA model had higher diagnostic efficiency compared to other clinical features. The analysis of Immune cell infiltration and ssGSEA further confirmed that predictive features were significantly associated with the immune status of ccRCC patients. Notably, the superimposed effect of patients in the high-risk group and high TMB resulted in shorter survival. In addition, the higher TIDE scores in the high-risk group suggested a poorer outcome for immune checkpoint blockade response in these patients.

Conclusion: The ten cuproptosis-related risk profiles for lncRNA may help assess the prognosis and molecular profile of ccRCC patients and improve treatment options, which can be further applied in the clinic.

Establishment and Validation of a Ferroptosis-Related lncRNA Signature for Prognosis Prediction in Lower-Grade Glioma

Background

The prognosis of lower-grade glioma (LGG) is highly variable, and more accurate predictors are still needed. The aim of our study was to explore the prognostic value of ferroptosis-related long non-coding RNAs (lncRNAs) in LGG and to develop a novel risk signature for predicting survival with LGG.

Methods

We first integrated multiple datasets to screen for prognostic ferroptosis-related lncRNAs in LGG. A least absolute shrinkage and selection operator (LASSO) analysis was then utilized to develop a risk signature for prognostic prediction. Based on the results of multivariate Cox analysis, a prognostic nomogram model for LGG was constructed. Finally, functional enrichment analysis, single-sample gene set enrichment analysis (ssGSEA), immunity, and m6A correlation analyses were conducted to explore the possible mechanisms by which these ferroptosis-related lncRNAs affect survival with LGG.

Results

A total of 11 ferroptosis-related lncRNAs related to the prognosis of LGG were identified. Based on prognostic lncRNAs, a risk signature consisting of 8 lncRNAs was constructed and demonstrated good predictive performance in both the training and validation cohorts. Correlation analysis suggested that the risk signature was closely linked to clinical features. The nomogram model we constructed by combining the risk signature and clinical parameters proved to be more accurate in predicting the prognosis of LGG. In addition, there were differences in the levels of immune cell infiltration, immune-related functions, immune checkpoints, and m6A-related gene expression between the high- and low-risk groups.

Conclusion

In summary, our ferroptosis-related lncRNA signature exhibits good performance in predicting the prognosis of LGG. This study may provide useful insight into the treatment of LGG.

A reduced level of the long non-coding RNA SNHG8 activates the NF-kappaB pathway by releasing functional HIF-1alpha in a hypoxic inflammatory microenvironment

BACKGROUND

A series of biochemical responses, including hypoxia and aseptic inflammation, occur in periodontal ligament cells (PDLCs) during periodontal tissue remodeling of orthodontic tooth movement (OTM). However, the role of long non-coding RNA (lncRNA) in these responses is still largely unknown. We investigated the role of the lncRNA SNHG8 in hypoxic and inflammatory responses during OTM and explored the underlying mechanisms.

METHODS

The expression pattern of SNHG8, and hypoxic and inflammatory responses under compressive force were analyzed by qRT-PCR, immunohistochemistry, and western blotting, in vivo and in vitro. The effect of overexpression or knockdown of SNHG8 on the nuclear factor-kappaB (NF-κB) pathway was evaluated. RNA sequencing was performed for mechanistic analysis. The interaction between SNHG8 and hypoxia-inducible factor (HIF)-1α was studied using catRAPID, RNA immunoprecipitation, and RNA pulldown assays. The effect of the SNHG8-HIF-1α interaction on the NF-κB pathway was determined by western blotting.

RESULTS

The NF-κB pathway was activated, and HIF-1α release was stabilized, in PDLCs under compressive force as well as in OTM model rats. The SNHG8 level markedly decreased both in vivo and in vitro. Overexpression of SNHG8 decreased the expression levels of inflammatory cytokines, the phosphorylation of p65, and the degradation of IκBα in PDLCs, whereas knockdown of SNHG8 reversed these effects. Mechanically, RNA sequencing showed that differentially expressed genes were enriched in cellular response to hypoxia after SNHG8 overexpression. SNHG8 binds to HIF-1α, thus preventing HIF-1 from activating downstream genes, including those related to the NF-κB pathway.

CONCLUSION

SNHG8 binds to HIF-1α. During OTM, the expression of SNHG8 dramatically decreased, releasing free functional HIF-1α and activating the downstream NF-κB pathway. These data suggest a novel lncRNA-regulated mechanism during periodontal tissue remodeling in OTM.

Long noncoding RNA SNHG17: a novel molecule in human cancers

Many studies in recent years have found that dysregulation of long non-coding RNAs (lncRNAs) can contribute to disease. Small nucleolar RNA host gene 17 (SNHG17) is a novel cancer-related lncRNA of the SNHG family which is highly expressed in various tumors and may exert oncogenic functions. Several studies have demonstrated that SNHG17 is closely related to the proliferation, migration, invasion, apoptosis, and chemical drug resistance of tumor cells, and clinical studies have found an association between high SNHG17 expression and poor prognosis. In this review, we summarize relevant studies investigating SNHG17, focusing on its biological function as well as its potential value for clinical applications.

Knockdown of long non-coding RNA SNHG8 suppresses the progression of esophageal cancer by regulating miR-1270/BACH1 axis

The emerging evidence showed that lncRNAs (long non-coding RNAs) could regulate the progression and affect the malignant behaviors of cancers. LncRNA SNHG8 (small nucleolar RNA host gene 8) has been reported to participate in most cancers development. Here in this study, the role of lncRNA SNHG8 in esophageal cancer was uncovered by a series of functional experiments. The expression pattern of SNHG8 in tumor tissues or cells was first detected by qRT-PCR. Using a lentivirus knockdown shRNA is to repress the expression of SNHG8. Subsequently, the in vitro and in vivo experiments were utilized to evaluate whether the malignant behaviors of esophageal cancer were influenced by knockdown SNHG8. The results indicated that lncRNA SNHG8 should be a cancer-promoting factor with a relatively high expression level in esophageal cancer. Moreover, knockdown SNHG8 inhibited the cell viability and induced cell apoptosis in KYSE30 and TE-1 cells. In addition, based on the results of the binding site analysis and the luciferase reporter system, SNHG8 functions by the miR-1270/BACH1 axis. The follow-up experiments verified that lncRNA SNHG8 could down-regulate the expression of miR-1270 to increase the BACH1 expression. Finally, we confirmed that knockdown SNHG8 retarded the progression of esophageal cancer with a xenograft model. To sum up, our findings suggested that lncRNA SNHG8 is a cancer-promoting factor in esophageal cancer. Knockdown SNHG8 could suppress the progression of esophageal cancer, which implies SNHG8 could be used as a therapeutic target in esophageal cancer.

Dysregulated lncRNA and mRNA may promote the progression of ischemic stroke via immune and inflammatory pathways: results from RNA sequencing and bioinformatics analysis

BACKGROUND

Long non-coding RNAs (lncRNAs) are widely involved in gene transcription regulation and which act as epigenetic modifiers in many diseases.

OBJECTIVE

To determine whether lncRNAs are involved in ischemic stroke (IS), we analyzed the expression profile of lncRNAs and mRNAs in IS.

METHODS

RNA sequencing was performed on the blood of three pairs of IS patients and healthy controls. Differential expression analysis was used to identify differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs). Based on the co-expression relationships between lncRNA and mRNA, a series of bioinformatics analysis including GO and KEGG enrichment analysis and PPI analysis, were conducted to predict the function of lncRNA.

RESULTS

RNA sequencing produced a total of 5 DElncRNAs and 144 DEmRNAs. Influenza A pathway and Herpes simplex infection pathway were the most significant pathways. EP300 and NFKB1 were the most important target proteins, and Human leucocyte antigen (HLA) family were the key genes in IS.

CONCLUSIONS

Analysis of this study revealed that dysregulated lncRNAs in IS may lead to IS by affecting the immune and inflammation system.

The role and mechanism of HLA complex group 11 in cancer

HLA is critical in a variety of diseases, including infectious disease and cancer, and has been used for diagnostic differentiation and immunosurveillance of certain diseases. In addition, emerging evidence suggests that the mutations and dysregulation of lncRNAs are essential contributors in cancers. HLA Complex Group 11 (HCG11) located on MHC region is affiliated with the lncRNA class. Studies have shown that HCG11 could serve as a key regulator in lung cancer, prostate cancer, glioma, cervical cancer and hepatocellular carcinoma. In this review, we summarize the accumulated information on the expression and clinical value of HCG11 in different cancer types, discuss its interactions with microRNAs, mRNAs, and proteins, and discover the biological roles and potential mechanisms of HCG11 in a variety of cellular functions, including cell proliferation, apoptosis, migration, and invasion. Further, we emphasize the possible application of HCG11 in treatment, summarize the studies of HCG11 in chemotherapy resistance and hormone therapy, and propose the significance of further study of HCG11.