Silencing long non‑coding RNA NEAT1 suppresses the tumorigenesis of infantile hemangioma by competitively binding miR‑33a‑5p to stimulate HIF1α/NF‑κB pathway

Puzzling out the role of MIAT LncRNA in hepatocellular carcinoma

A non-negligible part of our DNA has been proven to be transcribed into non-protein coding RNA and its intricate involvement in several physiological processes has been highly evidenced. The significant biological role of non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs) has been variously reported. In the current review, the authors highlight the multifaceted role of myocardial infarction-associated transcript (MIAT), a well-known lncRNA, in hepatocellular carcinoma (HCC). Since its discovery, MIAT has been described as a regulator of carcinogenesis in several malignant tumors and its overexpression predicts poor prognosis in most of them. At the molecular level, MIAT is closely linked to the initiation of metastasis, invasion, cellular migration, and proliferation, as evidenced by several in-vitro and in-vivo models. Thus, MIAT is considered a possible theranostic agent and therapeutic target in several malignancies. In this review, the authors provide a comprehensive overview of the underlying molecular mechanisms of MIAT in terms of its downstream target genes, interaction with other classes of ncRNAs, and potential clinical implications as a diagnostic and/or prognostic biomarker in HCC.

Oxidative stress-induced endothelial cells-derived exosomes accelerate skin flap survival through Lnc NEAT1-mediated promotion of endothelial progenitor cell function

Background

Flap transplantation is commonly used in reconstructive surgery. A prerequisite for skin flap survival is sufficient blood supply. However, such approaches remain unclear. This study aimed to explore the underlying mechanisms of exosomes derived from human umbilical vascular endothelial cells (HUVECs) exposed to oxidative stress on endothelial progenitor cells (EPCs) and their subsequent influence on the survival of skin flaps.

Methods

HUVECs were treated with various concentrations of H₂O₂ to establish an oxidative stress model. To investigate the effects of H₂O₂-HUVEC-Exos and HUVEC-Exos, Cell Counting Kit-8, tube formation, invasion assays, and quantitative real-time polymerase chain reaction (qRT-PCR) were performed in EPCs. Microarray analysis was used to reveal the differentially expressed long non-coding RNAs (lncRNAs) in the H₂O₂-HUVEC-Exos and HUVEC-Exos. In addition, gene silencing and western blotting were employed to determine the mechanism behind lncRNA nuclear enrichment enriched transcript 1 (Lnc NEAT1) in EPCs. Further, a rat skin flap model was used to determine the role of the exosomes in skin flap survival in vivo.

Results

HUVECs were stimulated with 100 μmol/L H₂O₂ for 12 h to establish an oxidative stress model. H₂O₂-HUVEC-Exos promoted the proliferation, tube formation, and invasion of EPCs and remarkably increased skin flap survival compared to the HUVEC-Exos and control groups. Sequencing of exosome RNAs revealed that the Lnc NEAT1 level was dramatically increased in the H₂O₂-HUVEC-Exos, leading to activation of the Wnt/β-catenin signaling pathway. Comparatively, knockdown of Lnc NEAT1 in HUVEC-Exos and H₂O₂-HUVEC-Exos significantly inhibits the angiogenic capacity of EPCs, reduced the survival area of skin flap and downregulated the expression levels of Wnt/β-catenin signaling pathway proteins, whereas Wnt agonist partly reversed the negative effect of NEAT1 downregulation on EPCs through the Wnt/β-catenin signaling pathway.

Conclusions

Exosomes derived from HUVECs stimulated by oxidative stress significantly promoted the pro-angiogenic ability of EPCs through the Wnt/β-catenin signaling pathway mediated by Lnc NEAT1 and hence enhanced random flap survival in vivo. Therefore, the application of H₂O₂-HUVEC-Exos may serve as an alternative therapy for improving random skin flap survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03013-9.

ALKBH5 promotes the progression of infantile hemangioma through regulating the NEAT1/miR-378b/FOSL1 axis

Our work aims to investigate long non-coding RNA (lncRNA) N6-methyladenosine (m⁶A) modification and its role in infantile hemangioma (IH). The mRNA and protein expression levels were assessed using quantitative real-time polymerase chain reaction, western blot and immunohistochemistry. Me-RIP assay was performed to evaluate lncRNA NEAT1 m⁶A levels. Cell proliferation, migration and invasion were evaluated using cell counting kit-8 assay, transwell migration and invasion assay, respectively. Photo-activatable ribonucleoside-enhanced crosslinking and immunoprecipitation assay was conducted to verify the binding relationship between lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) and ALKBH5 (an RNA demethylase). The binding relationship between lncRNA NEAT1, microRNA (miR)-378b and FOS-like antigen 1 (FOSL1) was verified using dual-luciferase reporter gene assay and/or RNA immunoprecipitation assay. ALKBH5, lncRNA NEAT1 and FOLS1 expression was elevated in IH tissues, while miR-378b was downregulated. ALKBH5 knockdown suppressed cell proliferation, migration and invasion of IH cells, while promoting cell apoptosis. ALKBH5 promoted lncRNA NEAT1 expression by reducing the m⁶A modification of lncRNA NEAT1. In addition, miR-378b was the target of lncRNA NEAT1, and its overexpression reversed the promotion effect of lncRNA NEAT1 overexpression on IH cell tumor-like behaviors. Moreover, FOLS1 was the target of miR-378b, and its overexpression reversed the inhibitory effect of miR-378b overexpression on IH cell tumor-like behaviors in vitro. ALKBH5 might have great potential as therapeutic target for IH, since ALKBH5 silencing suppressed IH progression by regulation of the NEAT1/miR-378b/FOSL1 axis.

Propranolol Suppresses Proliferation and Migration of HUVECs through Regulation of the miR-206/VEGFA Axis

Propranolol has been used in the first-line therapy of infantile hemangioma (IH) for a number of years; however, the mechanisms through which propranolol regulates IH are not yet fully understood. In the present study, microRNA (miRNA/miR) sequencing analysis was performed to identify differentially expressed miRNAs in human umbilical vascular endothelial cells (HUVECs) treated with propranolol. Cell viability and apoptosis were detected using CCK-8 assay and flow cytometry, respectively. Cell migration was assessed using wound healing, Transwell, and tube formation assays. Methylation-specific PCR was then used to investigate the promoter methylation status. The levels of oxidative stress indicators, including superoxide dismutase, glutathione, and malondialdehyde were also detected. Finally, cell cycle analysis was performed using flow cytometry and western blotting. It was observed that propranolol induced the upregulation of miR-206 in HUVECs, which was caused by demethylation of the miR-206 promoter. Moreover, propranolol significantly inhibited the proliferation of HUVECs by inducing apoptosis, while these phenomena were reversed by miR-206 antagomir. VEGFA was found to be a target gene of miR-206. In addition, propranolol notably inhibited the migration and induced G1 arrest of the HUVECs, whereas these results were eliminated by miR-206 antagomir. Collectively, the findings of the present study demonstrated that propranolol may inhibit the proliferation and migration in HUVECs via modulating the miR-206/VEGFA axis. These findings suggest a novel mechanism through which propranolol suppresses the progression of IH.

Study on the Mechanism of Capillary Leakage Caused by Hypoxia-Inducible Factor-1α through Inducing High Expression of Matrix Metalloproteinase-9

Purposes

This study mainly explored the mechanism of capillary leakage caused by hypoxia-inducible factor-1α through inducing high expression of matrix metalloproteinase-9. Method. We established a monolayer endothelial cell model by culturing human umbilical vein endothelial cells (HUVEC) in vitro, used tumor necrosis factor (TNFα) and HIF-1α inhibitor 2-methoxyestradiol (2ME2) to act on HUVEC, and at the same time constructed siRNA-transfected HUVEC to interfere with the expression of HIF-1α. The permeability of monolayer endothelial cells was measured by transwell chamber method, the concentration of MMP-9 in the supernatant was measured by ELISA method, the expression of key molecules related to permeability (HIF- 1α, MMP-9, claudin-5, and ZO-1) was measured by RT-PCR and Western blot method, and the localization and expression of claudin-5 and ZO-1 were measured by immunofluorescence method. We searched for 7 HIF-1α hypoxia response elements within 4000 bp before the transcription start site in the MMP-9 promoter region, constructed the MMP-9 promoter-luciferase reporter gene recombinant plasmid, transfected and stimulated HUVEC with TNFα, and detected the effect of 7 hypoxia response element plasmids on the transcription activity of MMP-9 promoter.

Results

Under the action of TNFα, the permeability of monolayer endothelial cells increased, and the concentration of MMP-9 in the cell supernatant increased. 2ME2 and HIF-1α-siRNA transfection can improve the above situation (P < 0.05). 2ME2 and HIF-1α-siRNA transfection can inhibit the high expression of HIF-1α and MMP-9 caused by TNFα, thereby increasing the expression of claudin-5 and ZO-1 (P < 0.05). 2ME2 and HIF-1α-siRNA transfection can reduce the inhibition of TNFα on the expression of cell membrane protein claudin-5 and tight junction protein ZO-1. Element 1, element 5, and element 7 are the sites where HIF-1α interacts with MMP-9 at the transcription level.

Conclusion

This study shows that HIF-1α can increase the permeability of monolayer epithelial cells by inducing the high expression of MMP-9, leading to capillary leakage. Its target is at the -3798 bp, -1878 bp, and -1489 bp points of the transcription initiation site in the MMP-9 promoter region.

NEAT1 as a competing endogenous RNA in tumorigenesis of various cancers: Role, mechanism and therapeutic potential

The nuclear paraspeckle assembly transcript 1 (NEAT1) is a long non-coding RNA (lncRNA) that is upregulated in a variety of human cancer types. Increasing evidence has shown that the elevation of NEAT1 in cancer cells promotes cell growth, migration, and invasion and inhibits cell apoptosis. It is also known that lncRNAs act as a competing endogenous RNA (ceRNA) by sponging microRNAs (miRNAs) to alter the expression levels of their target genes in the development of cancers. Therefore, it is important to understand the molecular mechanisms underlying this observation. In this review, specific emphasis was placed on NEAT1's role in tumor development. We also summarize and discuss the feedback roles of NEAT1/miRNA/target network in the progression of various cancers. As our understanding of the role of NEAT1 during tumorigenesis improves, its therapeutic potential as a biomarker and/or target for cancer also becomes clearer.

LncRNA-TUG1 promotes the progression of infantile hemangioma by regulating miR-137/IGFBP5 axis

Background

Previous studies indicated that lncRNA taurine upregulated gene 1 (TUG1) played essential roles in human cancers. This study aimed to investigate its function in infantile hemangioma (IH).

Methods

A total of 30 pairs of clinical infantile specimens were used in this study. The expression of TUG1 in IH tissues was assessed by quantitative reverse transcriptase PCR (qRT-PCR). Two short hairpin RNA targeting TUG1 (sh-TUG1-1 and sh-TUG1-2) were transfected into hemangioma-derived endothelial cells, HemECs, to block its expression. The effects of TUG1 on HemECs were evaluated by Cell Counting Kit-8 (CCK-8), colony formation assay, wound healing assay, and Transwell assay. The underlying molecular mechanism of TUG1 was investigated by Starbase prediction and luciferase reporter assay and further determined by loss- and gain-of-function approaches. In addition, the role of TUG1 on tumorigenesis of HemECs was confirmed in an in vivo mouse model.

Results

TUG1 was significantly upregulated in infant hemangioma tissues compared with normal adjacent subcutaneous tissues. The loss- and gain-of-function approaches indicated that TUG1 overexpression promoted proliferation, migration, and invasion of HemECs in vitro, and TUG1 knockdown inhibited the tumorigenesis of HemECs in vivo. Specifically, TUG1 could compete with IGFBP5 for miR137 binding. Rescue experiments further confirmed the role of the TUG1/miR137/IGFBP5 axis in HemECs.

Conclusion

TUG1 was closely associated with the progression of IH by regulating the miR-137/IGFBP5 axis, which might be a potential target for IH treatment.

Long non-coding RNA nuclear paraspeckle assembly transcript 1 promotes activation of T helper 2 cells via inhibiting STAT6 ubiquitination

T helper (Th) 2 cell-medicated immune response participates in various immune diseases, including systemic lupus erythematosus (SLE). Long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) has been reported to be associated with T helper 2 (Th2) cell activation. Here, we demonstrated the molecular mechanism of NEAT1 in regulating Th2 cell activation. We found that NEAT1 was located in nucleus. NEAT1 overexpression promoted the levels of Th2-related cytokines IL-4, IL-5 and IL-13 in CD4⁺ T cells. Moreover, NEAT1 up-regulation reduced Th1-related cytokine INF-γ production and enhanced the levels of Th17-related cytokines IL-17 in CD4⁺ T cells. STAT6 deficiency reduced the levels of IL-4, IL-5, IL-13 and IL-17 enhanced the levels of INF-γ in CD4⁺ T cells, which was rescued by NEAT1 overexpression. Moreover, NEAT1 promoted STAT6 protein expression, whereas NEAT1 had no effect on the expression of STAT6 mRNA. Furthermore, NEAT1 interacted with STAT6, inhibited the ubiquitination of STAT6 in CD4⁺ T cells. In conclusion, our work has confirmed that NEAT1 promotes STAT6 expression by inhibiting STAT6 ubiquitination, thereby promoting Th2 cell activation. Thus, our work may highlight novel insights into the molecular mechanism of NEAT1 in regulating Th2 cell activation.