LncRNA APOA1-AS facilitates proliferation and migration and represses apoptosis of VSMCs through TAF15-mediated SMAD3 mRNA stabilization

CypA/TAF15/STAT5A/miR-514a-3p feedback loop drives ovarian cancer metastasis

Cyclophilin A (CypA) is a peptidyl-prolyl isomerase that participates in multiple cancer events, but the molecular mechanisms of abnormal expression and regulation of CypA in ovarian cancer (OC) have never been considered. This study identifies CypA as a key driver of epithelial-mesenchymal transition (EMT) in ovarian cancer and explores the mechanisms that underly this process. We show that CypA is upregulated in tissues and serum of ovarian cancer patients and that CypA overexpression correlates with poor prognosis. CypA facilitates tumor growth and metastasis in vivo in subcutaneous tumor xenograft and abdominal metastatic models, and in vitro studies suggest a mechanism, showing that CypA accelerates ovarian cancer cell epithelial-mesenchymal transition by activating a PI3K/AKT signaling pathway. Mechanistic studies showed that STAT5A binds pri-miR-514a-3p and inhibits its activity, whereas miR-514a-3p directly binds to the 3'-UTR of CypA to suppress its expression, resulting in STAT5A promoting the expression of CypA, forming the STAT5A/miR-514a-3p/CypA axis. Furthermore, immunoprecipitates and mass spectrometry analysis identifies a CypA interaction with TAF15 that stabilizes TAF15 by suppressing its proteasome degradation and promotes its entry into the nucleus. While STAT5A is positively regulated by TAF15. Our findings identify a novel feedback loop for CypA that drives EMT and ovarian tumor growth and metastasis via a TAF15/STAT5A/miR-514a-3p pathway in ovarian cancer and facilitates the release of CypA into the extracellular, which provides a promising therapeutic target for OC treatment and a diagnostic biomarker.

TAF15 inhibits p53 nucleus translocation and promotes HCC cell 5-FU resistance via post-transcriptional regulation of UBE2N

Chemotherapy resistance is an important factor responsible for the low 5-year survival rate of hepatocellular carcinoma (HCC) patients. Ubiquitin-conjugating enzyme E2N (UBE2N) is a cancer-associated ubiquitin-conjugating enzyme that is expressed in HCC tissues, and its high expression is associated with a poor prognosis. This study explored the role played by UBE2N in development of 5-fluorouracil (5-FU) resistance in HCC cells. Three HCC cell lines (HepG2 [p53 wild type], Huh7 [p53 point mutant type], Hep3B [p53 non-expression type]), and one normal liver cell line (MIHA) were used in our present study. The IC50 value of 5-FU was determined using a cell counting kit-8 (CCK-8) assay. Cell viability was assessed by colony formation assays. TUNEL assays and flow cytometry were used to analyze cell apoptosis. RNA pull-down and RNA immunoprecipitation (RIP) assays were performed to confirm the binding relationship between UBE2N mRNA and TAF15 protein. Our results showed that TAF15 and UBE2N were highly expressed in HCC cells. UBE2N inhibited the translocation of p53 protein into the cell nucleus to increase 5-FU resistance, as reflected by an increased IC50 value, an increase in cell viability, and a reduction in cell apoptosis. Overexpression of p53 reduced 5-FU resistance, but that effect could be reversed by UBE2N overexpression. TAF15 protein bound to and stabilized UBE2N mRNA, thereby inhibiting p53 translocation into the nucleus and promoting 5-FU resistance in HCC cells. Collectively, our present study identified a novel mechanism by which TAF15/UBE2N regulates p53 distribution to increase 5-FU resistance. Our results also suggest potential therapeutic strategies for treating HCC.

Circular RNAs regulate neuron size and migration of midbrain dopamine neurons during development

Midbrain dopamine (mDA) neurons play an essential role in cognitive and motor behaviours and are linked to different brain disorders. However, the molecular mechanisms underlying their development, and in particular the role of non-coding RNAs (ncRNAs), remain incompletely understood. Here, we establish the transcriptomic landscape and alternative splicing patterns of circular RNAs (circRNAs) at key developmental timepoints in mouse mDA neurons in vivo using fluorescence-activated cell sorting followed by short- and long-read RNA sequencing. In situ hybridisation shows expression of several circRNAs during early mDA neuron development and post-transcriptional silencing unveils roles for different circRNAs in regulating mDA neuron morphology. Finally, in utero electroporation and time-lapse imaging implicate circRmst, a circRNA with widespread morphological effects, in the migration of developing mDA neurons in vivo. Together, these data for the first time suggest a functional role for circRNAs in developing mDA neurons and characterise poorly defined aspects of mDA neuron development.

APOA1/C3/A4/A5 Gene Cluster at 11q23.3 and Lipid Metabolism Disorders: From Epigenetic Mechanisms to Clinical Practices

The APOA1/C3/A4/A5 cluster is an essential component in regulating lipoprotein metabolism and maintaining plasma lipid homeostasis. A genome-wide association analysis and Mendelian randomization have revealed potential associations between genetic variants within this cluster and lipid metabolism disorders, including hyperlipidemia and cardiovascular events. An enhanced understanding of the complexity of gene regulation has led to growing recognition regarding the role of epigenetic variation in modulating APOA1/C3/A4/A5 gene expression. Intensive research into the epigenetic regulatory patterns of the APOA1/C3/A4/A5 cluster will help increase our understanding of the pathogenesis of lipid metabolism disorders and facilitate the development of new therapeutic approaches. This review discusses the biology of how the APOA1/C3/A4/A5 cluster affects circulating lipoproteins and the current progress in the epigenetic regulation of the APOA1/C3/A4/A5 cluster.

Two sides of the same coin: Non-alcoholic fatty liver disease and atherosclerosis

The prevalence of non-alcoholic fatty liver disease (NAFLD) and atherosclerosis remain high, which is primarily due to widespread adoption of a western diet and sedentary lifestyle. NAFLD, together with advanced forms of this disease such as non-alcoholic steatohepatitis (NASH) and cirrhosis, are closely associated with atherosclerotic-cardiovascular disease (ASCVD). In this review, we discussed the association between NAFLD and atherosclerosis and expounded on the common molecular biomarkers underpinning the pathogenesis of both NAFLD and atherosclerosis. Furthermore, we have summarized the mode of function and potential clinical utility of existing drugs in the context of these diseases.

TAF15 exacerbates nonalcoholic steatohepatitis progression by regulating lipid metabolism and inflammation via FASN and p65 NF-κB

BACKGROUND & AIMS

Nonalcoholic fatty liver disease (NAFLD) consists of a broad spectrum of conditions, and nonalcoholic steatohepatitis (NASH) is the advanced form of NAFLD. TAF15 is a DNA and RNA binding protein and is involved in crucial inflammatory signalling pathways. We aimed to investigate the role of TAF15 in the progression of NASH and the underlying molecular mechanism.

METHODS

We generated mice with hepatocyte-specific knockdown and overexpression of TAF15 using a specific adeno-associated virus (AAV). NASH models were established by feeding mice high-fat and high-cholesterol diets and methionine- and choline-deficient diets. Cleavage under targets and tagmentation and dual-luciferase reporter assays were performed to investigate the effect of TAF15 on FASN transcription. Coimmunoprecipitation and immunofluorescence assays were conducted to explore the interaction of TAF15 and p65. In vitro coculture systems were established to study the interactions of hepatocytes, macrophages and HSCs.

RESULTS

TAF15 was significantly increased in the livers of mouse NASH models and primary hepatocyte NASH model. Knockdown of TAF15 inhibited steatosis, inflammation and fibrosis, while overexpression of TAF15 promoted NASH phenotypes. Mechanistically, TAF15 bound directly to the promoter region of FASN to facilitate its expression, thereby promoting steatosis. Moreover, TAF15 interacted with p65 and activated the NF-κB signalling pathway, increasing the secretion of proinflammatory cytokines and triggering M1 macrophage polarization. Treatment with the FASN inhibitor orlistat partially reversed the phenotypes.

CONCLUSIONS

These results suggested that TAF15 exacerbated NASH progression by regulating lipid metabolism and inflammation via transcriptional activation of FASN and interacting with p65 to activate the NF-κB signalling pathway.

Long non-coding RNA-targeting therapeutics: discovery and development update

INTRODUCTION

lncRNAs are major players in regulatory networks orchestrating multiple cellular functions, such as 3D chromosomal interactions, epigenetic modifications, gene expression and others. Due to progress in the development of nucleic acid-based therapeutics, lncRNAs potentially represent easily accessible therapeutic targets.

AREAS COVERED

Currently, significant efforts are directed at studies that can tap the enormous therapeutic potential of lncRNAs. This review describes recent developments in this field, particularly focusing on clinical applications.

EXPERT OPINION

Extensive druggable target range of lncRNA combined with high specificity and accelerated development process of nucleic acid-based therapeutics open new prospects for treatment in areas of extreme unmet medical need, such as genetic diseases, aggressive cancers, protein deficiencies, and subsets of common diseases caused by known mutations. Although currently wide acceptance of lncRNA-targeting nucleic acid-based therapeutics is impeded by the need for parenteral or direct-to-CNS administration, development of less invasive techniques and orally available/BBB-penetrant nucleic acid-based therapeutics is showing early successes. Recently, mRNA-based COVID-19 vaccines have demonstrated clinical safety of all aspects of nucleic acid-based therapeutic technology, including multiple chemical modifications of nucleic acids and nanoparticle delivery. These trends position lncRNA-targeting drugs as significant players in the future of drug development, especially in the area of personalized medicine.

TATA-box-binding protein-associated factor 15 is a novel biomarker that promotes cell proliferation and migration in gastrointestinal stromal tumor

BACKGROUND

Gastrointestinal stromal tumor (GIST) is a common neoplasm with high rates of recurrence and metastasis, and its therapeutic efficacy is still not ideal. There is an unmet need to find new molecular therapeutic targets for GIST. TATA-box-binding protein-associated factor 15 (TAF15) contributes to the progress of various tumors, while the role and molecular mechanism of TAF15 in GIST progression are still unknown.

AIM

To explore new molecular therapeutic targets for GIST and understand the biological role and underlying mechanisms of TAF15 in GIST progression.

METHODS

Proteomic analysis was performed to explore the differentially expressed proteins in GIST. Western blotting and immunohistochemical analysis were used to verify the expression level of TAF15 in GIST tissues and cell lines. Cell counting kit-8, colony formation, wound-healing and transwell assay were executed to detect the ability of TAF15 on cell proliferation, migration and invasion. A xenograft mouse model was applied to explore the role of TAF15 in the progression of GIST. Western blotting was used to detect the phosphorylation level and total level of RAF1, MEK and ERK1/2.

RESULTS

A total of 1669 proteins were identified as differentially expressed proteins with 762 upregulated and 907 downregulated in GIST. TAF15 was selected for the further study because of its important role in cell proliferation and migration. TAF15 was significantly over expressed in GIST tissues and cell lines. Overexpression of TAF15 was associated with larger tumor size and higher risk stage of GIST. TAF15 knockdown significantly inhibited the cell proliferation and migration of GIST in vitro and suppressed tumor growth in vivo. Moreover, the inhibition of TAF15 expression significantly decreased the phosphorylation level of RAF1, MEK and ERK1/2 in GIST cells and xenograft tissues, while the total RAF1, MEK and ERK1/2 had no significant change.

CONCLUSION

TAF15 is over expressed in GIST tissues and cell lines. Overexpression of TAF15 was associated with a poor prognosis of GIST patients. TAF15 promotes cell proliferation and migration in GIST via the activation of the RAF1/MEK/ERK signaling pathway. Thus, TAF15 is expected to be a novel latent molecular biomarker or therapeutic target of GIST.

TAF15 promotes cell proliferation, migration and invasion of gastric cancer via activation of the RAF1/MEK/ERK signalling pathway

TATA-box-binding protein-associated Factor 15 (TAF15), a member of the FUS/EWS/TAF15 (FET) family, contributes to the progression of various tumours. However, the role and molecular mechanism of TAF15 in gastric cancer (GC) progression are still unknown. In this study, we found that TAF15 was significantly upregulated in GC tumour tissues and cell lines. Overexpression of TAF15 was associated with a larger tumour size, high pathologic stage and high T stage of GC. TAF15 knockdown suppressed the proliferation, migration and invasion of GC cells in vitro and inhibited the tumour growth in vivo. Additionally, TAF15 knockdown led to the significant reductions in the phosphorylation levels of RAF1, MEK and ERK1/2, while total RAF1, MEK and ERK1/2 exhibited no significant change in GC cell lines. In summary, TAF15 is overexpressed in GC tumour tissues and cell lines, and promotes cell proliferation, migration and invasion in GC via the RAF1/MEK/ERK signaling pathway, which suggests that TAF15 might be a potential molecular diagnostic marker or therapeutic target for GC.

CircDNAJC11 interacts with TAF15 to promote breast cancer progression via enhancing MAPK6 expression and activating the MAPK signaling pathway

BACKGROUND

Breast cancer (BC) is a common malignant tumor in women worldwide. Circular RNA (circRNA) has been proven to play a critical role in BC progression. However, the exact biological functions and underlying mechanisms of circRNAs in BC remain largely unknown.

METHODS

Here, we first screened for differentially expressed circRNAs in 4 pairs of BC tissues and adjacent non-tumor tissues using a circRNA microarray. Functionally, gain- and loss-of-function experiments in vitro and in vivo showed that circDNAJC11 promoted BC cell proliferation, migration, invasion, and tumor growth. Mechanistically, RNA pull-down, mass spectrum, RNA immunoprecipitation, fluorescence in situ hybridization assays, and rescue experiments were executed.

RESULTS

We found that circDNAJC11 was significantly upregulated in triple-negative breast cancer tissues and cells. Clinical data revealed that the high expression of circDNAJC11 was closely correlated with a poor prognosis of BC patients and could be an independent risk factor for BC prognosis. Functionally, gain- and loss-of-function experiments in vitro and in vivo showed that circDNAJC11 promoted BC cell proliferation, migration, invasion, and tumor growth. Mechanistically, RNA pull-down, mass spectrum, RNA immunoprecipitation, fluorescence in situ hybridization assays, and rescue experiments were executed. We demonstrated that circDNAJC11 combined with TAF15 to promote BC progression via stabilizing MAPK6 mRNA and activating the MAPK signaling pathway.

CONCLUSIONS

The circDNAJC11/TAF15/MAPK6 axis played a crucial role in the progression and development of BC, suggesting that circDNAJC11 might be a novel biomarker and therapeutical target for BC.

Identification of signalling downstream of the transcription factor forkhead box protein M1 that protects against endoplasmic reticulum stress in a diabetic foot ulcer model

AIMS

Diabetic foot ulcer (DFU) has a significant impact on the quality of life of diabetic mellitus (DM) patients. Here, we aimed to explore the molecules with aberrant expression and their regulatory mechanisms in DFU.

METHODS

The expression of gene and protein was examined using quantitative polymerase chain reaction (qPCR) and western blot. Pearson's correlation analysis was used to analyse interactions among FOXM1, GAS5 and SDF4. Immunofluorescence was used to detect PDI and GRP78 expression. Flow cytometry was used to assess cell apoptosis. Tube formation assay was used to determine angiogenic capacity. Fluorescence in situ hybridization (FISH) assay was employed to determine the cellular localization of GAS5 and SDF4 in human umbilical vein endothelial cells (HUVECs). The interactions among FOXM1, GAS5 and SDF4 were validated by chromatin immunoprecipitation (ChIP), luciferase, RNA pull-down and RNA immunoprecipitation (RIP) assays.

RESULTS

FOXM1, GAS5 and SDF4 were decreased in the skin tissues of DFU patients. High glucose (HG) stimulation induced endoplasmic reticulum (ER) stress and cell apoptosis but suppressed angiogenesis in HUVECs, which were abolished by FOXM1 overexpression. FOXM1 promoted GAS5 transcriptional activity, resulting in increased GAS5 expression, and GAS5 knockdown reversed the effects of FOXM1 overexpression in HG-treated HUVECs. Moreover, GAS5 recruited TAF15 to promote SDF4 expression in HUVECs. GAS5 overexpression inhibited ER stress, cell apoptosis and induced angiogenesis in HG-treated HUVECs which could be reversed by silencing SDF4.

CONCLUSION

Our results revealed that FOXM1 suppressed ER stress, cell apoptosis and promoted angiogenesis in HG-induced HUVECs via mediating GAS5/TAF15/SDF4 axis, providing a novel therapeutic molecule mechanism for DFU.

Natural antisense transcripts as drug targets

The recent discovery of vast non-coding RNA-based regulatory networks that can be easily modulated by nucleic acid-based drugs has opened numerous new therapeutic possibilities. Long non-coding RNA, and natural antisense transcripts (NATs) in particular, play a significant role in networks that involve a wide variety of disease-relevant biological mechanisms such as transcription, splicing, translation, mRNA degradation and others. Currently, significant efforts are dedicated to harnessing these newly emerging NAT-mediated biological mechanisms for therapeutic purposes. This review will highlight the recent clinical and pre-clinical developments in this field and survey the advances in nucleic acid-based drug technologies that make these developments possible.

circVMA21 combining with TAF15 stabilizes SOCS3 mRNA to relieve septic lung injury through regulating NF-κB activation

BACKGROUND

Lung injury is a severe complication of sepsis, which brings great threats and challenges to human health. CircVMA21 has exhibited powerful anti- inflammation capacity. However, its underlying molecule mechanism remains blurry.

METHODS

Lipopolysaccharide (LPS) was used to treat mice and WI-38 cells to establish models of lung injury caused by sepsis. Lung injury was evaluated using HE staining. Cell apoptosis was tested by TUNEL and flow cytometry. Levels of inflammatory cytokines were detected using ELISA assay. CircVMA21 and SOCS3 expression was measured using RT-qPCR. The ROS, MDA, SOD and GSH production were monitored by commercial kits. The protein expression was examined with western blot. The correlations among circVMA21, SOCS3 and TAF15 were confirmed using RIP and RNA-pull down.

RESULTS

The expression of circVMA21 and SOCS3 was downregulated in LPS-induced lung injury of mice and WI-38 cells. Overexpressing circVMA21 or SOCS3 assuaged LPS-induced cell injury through repressing the levels of inflammatory factors, oxidative stress and cell apoptosis. NF-κB signaling pathway was inactivated by circVMA21 or SOCS3 overexpression. circVMA21 enhanced the stabilization of SOCS3 mRNA via interplaying with TAF15. SOCS3 knockdown destroyed the beneficial impacts of circVMA21 overexpression on LPS-induced cell injury.

CONCLUSION

CircVMA21 suppressed LPS-induced the levels of inflammatory factors, oxidative stress and cell apoptosis and improved LPS-induced lung injury by mediating TAF15/SOCS3/NF-κB axis.

IL-1β promotes A7r5 and HASMC migration and invasion via the p38-MAPK/Angpt-2 pathway

The migration, proliferation, and inflammatory factor secretion of vascular smooth muscle cells (VSMCs) are involved in the important pathological processes of several vascular occlusive diseases, including coronary atherosclerosis (CAS). Interleukin 1β(IL-1β), as a bioactive mediator of VSMC synthesis and secretion, can promote the pathological progress of CAS. In this study, we further explored the underlying molecular mechanisms by which IL-1β regulates VSMC migration, invasion. We pretreated A7r5 and HASMC with IL-1β for 24 h, and measured the expression of IL-1β, proliferating cell nuclear antigen (PCNA), cyclin D1, matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 2 (MMP9) in the cells by Western blotting. Cell migration and invasion ability were measured by Transwell and wound healing assays. Cell viability was measured by an MTT assay. We found that IL-1β upregulated the expression of proliferation-related proteins (PCNA and Cyclin D1) in A7r5 and HASMC, and induces the secretion of MMP2 and MMP9, promotes cell invasion and migration. In addition, in A7r5 and HASMCs treated with IL-1β, the expression of Angiopoietin-2 (Angpt-2) increased in a time-dependent manner, transfection with si-Angpt-2 suppressed cell migration and invasion, with downregulated MMP2 and MMP9 expression. Parallelly, we further found that the p38-MAPK pathway is activated in cells induced by IL-1β, p38-MAPK inhibitors can down-regulate the expression of Angpt-2. Collectively, these data demonstrated that IL-1β promotes A7r5 and HASMC migration and invasion via the p38-MAPK/Angpt-2 pathway.