Human umbilical cord mesenchymal stem cell-derived exosomes loaded miR-451a targets ATF2 to improve rheumatoid arthritis.

OBJECTIVE: Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic joint inflammation, with synovial fibroblasts (SFs) playing a pivotal role in its pathogenesis. Dysregulation of microRNA (miRNA) expression in SFs contributes to RA development. Exosomes (Exos) have emerged as effective carriers for therapeutic molecules, facilitating miRNA transfer between cells. This study explores the therapeutic potential of Exos derived from human umbilical cord mesenchymal stem cells (hUCMSCs), loaded with miR-451a, to modulate ATF2 expression, aiming to address RA in both in vivo and in vitro settings. METHODS: In this study, hUCMSC and RA SFs were isolated and identified, and hUCMSC-Exos were extracted and characterized. The influence of hUCMSC-Exos on RA SFs was detected. And hUCMSC-Exos targeting RA SFs was traced. HUCMSCKD-AGO2 was prepared by knocking down AGO2 in hUCMSC. HUCMSCKD-AGO2-Exos was extracted and characterized,and their influence on RA SFs was detected. The miRNA profiles before and after hUCMSC-Exos intervention in RA SFs were mapped to identify differential miRNAs. RT-qPCR was used to verify the differential miRNAs, with hsa-miR-451a finally selected as the target gene. The effect of miR-451a on SFs was detected. The latent binding of miR-451a to activating transcription factor 2 (ATF2) was analyzed. The effect of hUCMSC-ExosmiR-451a on SFs was detected, and the expression of miR-451a and ATF2 was measured by RT-PCR. In vivo, hUCMSC-ExosmiR-451a was injected into the ankle joint of CIA rats, and arthritis index, joint imaging and synovial pathology were assessed. The expression of miR-451a and ATF2 in synovial tissue was detected. Finally, the safety of hUCMSC-ExosmiR-451a in CIA rats was evaluated. RESULTS: This study revealed that hUCMSC-Exos can inhibit RA SFs proliferation, migration and invasion through miRNAs. High throughput sequencing detected 13 miRNAs that could be transmitted from hUCMSCs to RA SFs via hUCMSC-Exos. miR-451a inhibited RA SFs proliferation, migration and invasion by regulating ATF2. hUCMSC-Exos loaded with miR-451a targeted ATF2 to inhibit RA SFs proliferation, migration and invasion, and improve joint inflammation and imaging findings in CIA rats. CONCLUSIONS: This study demonstrates that miR-451a carried by hUCMSC-Exos can play a role in inhibiting RA SFs biological traits and improving arthritis in CIA rats by inhibiting ATF2. The findings suggest a promising treatment for RA and provide insights into the mechanism of action of hUCMSC-Exos in RA. Future research directions will continue to explore the potential in this field.

Regulatory role of the p38 MAPK/ATF2 signaling pathway in visual function and visual cortical plasticity in mice with monocular deprivation.

BACKGROUND: This study aimed to examine the role of the p38 mitogen-activated protein kinase (MAPK)/ activating transcription factor 2 (ATF2) signaling in visual function impairment and visual cortical plasticity in mice with monocular deprivation (MD). METHODS: Visual behavioral tests, including visual water task, visual cliff test, and flash visual evoked potential, were performed on each group. We studied the density of dendritic spines and the synaptic ultrastructure by Golgi staining and transmission electron microscope. We performed Western blot and immunohistochemistry and detected the expression of ATF2, PSD-95, p38 MAPK, and phosphor-p38 MAPK in the left visual cortex. RESULTS: In the MD + SB group, the visual acuity in deprived eyes substantially improved, the impairment of visual depth perception was alleviated, and the P wave amplitude and C/I ratio increased. The density of dendritic spines and the numerical density of synapses increased significantly, the width of the synaptic cleft decreased significantly, and the length of the active synaptic zone and the thickness of post-synaptic density (PSD) increased substantially. The protein expression of phosphor-p38 MAPK decreased, whereas that of PSD-95 and ATF2 increased significantly. CONCLUSIONS: Inhibiting the phosphorylation of p38 MAPK and negative feedback upregulated ATF2 expression, alleviated damage to visual function, and protected against synaptic plasticity in mice with MD.

ATF2 orchestrates macrophage differentiation and activation to promote antibacterial responses.

The differentiation and activation of macrophages are critical regulatory programs that are central to host inflammation and pathogen defense. However, the transcriptional regulatory pathways involved in these programs are not well understood. Herein, we demonstrate that the activity and expression of the transcription factor ATF2 is precisely regulated during primary human monocyte-to-macrophage differentiation and that its activation is linked to M1 polarization and antibacterial responses. Genetic perturbation experiments demonstrated that deletion of ATF2 (THP-ΔATF2) resulted in irregular and abnormal macrophage morphology, whereas macrophages overexpressing ATF2 (THP-ATF2) developed round and pancake-like morphology, resembling classically activated (M1) macrophages. Mechanistically, we show that ATF2 binds to the core promoter of PPM1A, a phosphatase that regulates monocyte-to-macrophage differentiation, to regulate its expression. Functionally, overexpression of ATF2 sensitized macrophages to M1 polarization, resulting in increased production of major histocompatibility complex class II, IL-1ß, and IP-10; improved phagocytic capacity; and enhanced control of the intracellular pathogen Mycobacterium tuberculosis. Gene expression profiling revealed that overexpression of ATF2 reprogramed macrophages to promote antibacterial pathways enriched in chemokine signaling, metabolism, and antigen presentation. Consistent with pathways analysis, metabolic profiling revealed that genetic overexpression or stimuli-induced activation of ATF2 alters the metabolic capacity of macrophages and primes these cells for glycolytic metabolism during M1 polarization or bacterial infection. Our findings reveal that ATF2 plays a central role during macrophage differentiation and M1 polarization to enhance the functional capacities of macrophages.

The transcription factor ATF2 promotes gastric cancer progression by activating the METTL3/cyclin D1 pathway.

Globally, gastric cancer (GC) is a major cause of cancer death. This study is aimed at investigating the biological functions of activating transcription factor 2 (ATF2) and the underlying mechanism in GC. In the present work, GEPIA, UALCAN, Human Protein Atlas and StarBase databases were adopted to analyze ATF2 expression characteristics in GC tissues and normal gastric tissues, and its relationships with tumor grade and patients' survival time. Quantitative real-time polymerase chain reaction (qRT-PCR) method was employed to examine ATF2 mRNA expression in normal gastric tissues, GC tissues, and GC cell lines. Cell counting kit-8 (CCK-8) and EdU assays were utilized for detecting GC cell proliferation. Cell apoptosis was detected by flow cytometry. PROMO database was applied to predict the binding site of ATF2 with the METTL3 promoter region. The binding relationship between ATF2 and the METTL3 promoter region was verified through dual-luciferase reporter gene assay and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) assay. Western blot was performed to evaluate the effect of ATF2 on METTL3 expression. METTL3-related signaling pathways were predicted using Gene Set Enrichment Analysis (GSEA) in the LinkedOmics database. It was found that, ATF2 level was elevated in GC tissues and cell lines in comparison with normal tissues and correlated with short patients' survival time. ATF2 overexpression facilitated GC cell growth and suppressed the apoptosis, whereas ATF2 knockdown suppressed GC cell proliferation and facilitated the apoptosis. ATF2 bound to the METTL3 promoter region, and ATF2 overexpression promoted the transcription of METTL3, and ATF2 knockdown restrained the transcription of METTL3. METTL3 was associated with cell cycle progression, and ATF2 overexpression enhanced cyclin D1 expression, and METTL3 knockdown reduced cyclin D1 expression. In summary, ATF2 facilitates GC cell proliferation and suppresses the apoptosis via activating the METTL3/cyclin D1 signaling pathway, and ATF2 is promising to be an anti-drug target for GC.

Inhibition of JNK/c-Jun-ATF2 Overcomes Cisplatin Resistance in Liver Cancer through down-Regulating Galectin-1.

Due to drug resistance, the clinical response to cisplatin (CDDP) from patients with liver cancer is unsatisfactory. The alleviation or overcoming of CDDP resistance is an urgent problem to be solved in clinics. Tumor cells rapidly change signal pathways to mediate drug resistance under drug exposure. Here, multiple phosphor-kinase assays were performed and c-Jun N-terminal kinase (JNK) was activated in liver cancer cells treated with CDDP. The high activity of the JNK promotes poor progression and mediates cisplatin resistance in liver cancer, leading to a poor prognosis of liver cancer. Mechanistically, the highly activated JNK phosphorylated c-Jun and ATF2 formed a heterodimer to upregulate the expression of Galectin-1, leading to promoting cisplatin resistance in liver cancer. Importantly, we simulated the clinical evolution of drug resistance in liver cancer by continuous CDDP administration in vivo. In vivo bioluminescence imaging showed the activity of JNK gradually increased during this process. Moreover, the inhibition of JNK activity by small molecular or genetic inhibitors enhanced DNA damage and overcame CDDP resistance in vitro and in vivo. Collectively, our results underline that the high activity of JNK/c-Jun-ATF2/Galectin-1 mediates cisplatin resistance in liver cancer and provides an optional scheme for dynamic monitoring of molecular activity in vivo.

USP14 Regulates ATF2/PIK3CD Axis to Promote Microvascular Endothelial Cell Proliferation, Migration, and Angiogenesis in Diabetic Retinopathy.

Diabetic retinopathy (DR) is one of the leading causes of blindness in diabetic patients. However, the pathogenesis of DR is complex, and no firm conclusions have been drawn so far. It has become a hot spot in ophthalmology research to deeply study the mechanism of DR pathological changes and find effective treatment options. Human retinal microvascular endothelial cells (HRMECs) were induced by high glucose (HG) to construct DR cell model. CCK-8 assay was used to detect the viability of HRMECs. Transwell assay was used to detect the migration ability of HRMECs. Tube formation assay was used to identify the tube formation ability of HRMECs. The expressions of USP14, ATF2 and PIK3CD were detected by Western blot analysis and qRT-PCR assay. Immunoprecipitation (IP) was used to ascertain the relationship of USP14 and ATF2. To explore the regulatory relationship between ATF2 and PIK3CD by dual-luciferase reporter gene assay and Chromatin immunoprecipitation (ChIP) assay. High glucose treatment promoted the proliferation, migration, and tube formation of HRMEC, and the expressions of USP14, ATF2 and PIK3CD were significantly up-regulated. USP14 or ATF2 knockdown inhibited HG-induced HRMECs proliferation, migration, and tube formation. USP14 regulated the expression of ATF2, and ATF2 promoted PIK3CD expression. PIK3CD overexpression attenuated the inhibitory effectiveness of USP14 knockdown on proliferation, migration and tube formation of DR cell model. Here, we revealed that USP14 regulated the ATF2/PIK3CD axis to promote proliferation, migration, and tube formation in HG-induced HRMECs.

Analysis of the interaction of a non-canonical twin half-site of Cyclic AMP-Response Element (CRE) with CRE-binding protein.

Differential regulation of a gene having either canonical or non-canonical cyclic AMP response element (CRE) in its promoter is primarily accomplished by its interactions with CREB (cAMP-response element binding protein). The present study aims to delineate the mechanism of the CREB-CRE interactions at the Oncostatin-M (osm) promoter by in vitro and in silico approaches. The non-canonical CREosm consists of two half-CREs separated by a short intervening sequence of 9 base pairs. In this study, in vitro binding assays revealed that out of the two CRE half-sites, the right half-CRE was indispensable for binding of CREB, while the left sequence showed weaker binding ability and specificity. Genome-wide modeling and high throughput free energy calculations for the energy-minimized models containing CREB-CREosm revealed that there was no difference in the binding of CREB to the right half of CREosm site when compared to the entire CREosm. These results were in accordance with the in vitro studies, confirming the indispensable role of the right half-CREosm site in stable complex formation with the CREB protein. Additionally, conversion of the right half-CREosm site to a canonical CRE palindrome showed stronger CREB binding, irrespective of the presence or absence of the left CRE sequence. Thus, the present study establishes an interesting insight into the interaction of CREB with a CRE variant located at the far end of a TATA-less promoter of a cytokine-encoding gene, which in turn could be involved in the regulation of transcription under specific conditions.

Intravital imaging of Wnt/ß-catenin and ATF2-dependent signalling pathways during tumour cell invasion and metastasis.

Wnt signalling has been implicated as a driver of tumour cell metastasis, but less is known about which branches of Wnt signalling are involved and when they act in the metastatic cascade. Here, using a unique intravital imaging platform and fluorescent reporters, we visualised ß-catenin/TCF-dependent and ATF2-dependent signalling activities during human cancer cell invasion, intravasation and metastatic lesion formation in the chick embryo host. We found that cancer cells readily shifted between states of low and high canonical Wnt activity. Cancer cells that displayed low Wnt canonical activity showed higher invasion and intravasation potential in primary tumours and in metastatic lesions. In contrast, cancer cells showing low ATF2-dependent activity were significantly less invasive both at the front of primary tumours and in metastatic lesions. Simultaneous visualisation of both these reporters using a double-reporter cell line confirmed their complementary activities in primary tumours and metastatic lesions. These findings might inform the development of therapies that target different branches of Wnt signalling at specific stages of metastasis.

Endoplasmic reticulum-resident protein Sec62 drives colorectal cancer metastasis via MAPK/ATF2/UCA1 axis.

OBJECTIVE: Metastasis is responsible for the poor prognosis of patients with colorectal cancer (CRC), and the role of aberrant expression of endoplasmic reticulum (ER) receptors in tumour metastasis has not been fully elucidated. The aim of the study is to ensure the role of ER-resident protein Sec62 in CRC metastasis and illuminate associated molecular mechanisms. MATERIALS AND METHODS: Bioinformatics analysis, qRT-PCR, western blot and immunohistochemistry assays were performed to evaluate the expression level and clinical significance of Sec62 in CRC. The specific role of Sec62 in CRC was identified by a series of functional experiments. We conducted RNA sequencing and rescue experiments to analyse the differentially expressed genes and identified UCA1 as a novel pro-metastasis target of Sec62 in CRC. Besides, the efficacy of MAPK/JNK inhibitor or agonist on Sec62-mediated CRC metastasis was evaluated by trans-well and wound healing assays. Finally, luciferase reporter and ChIP assay were employed to further explore the potential mechanisms. RESULTS: The abnormally elevated expression of Sec62 predicted poor prognosis of CRC patients and facilitated malignant metastasis of CRC cells. Mechanistically, Sec62 enhanced UCA1 expression through activating MAPK/JNK signalling pathway. And the p-JNK activating ATF2 could transcriptionally regulate UCA1 expression. Furthermore, blocking or activating MAPK/JNK signalling with JNK inhibitor or agonist potently suppressed or enhanced Sec62 mediated CRC metastatic process. CONCLUSIONS: Our study reports for the first time that the Sec62/MAPK/ATF2 /UCA1 axis exists in CRC metastatic process, which could be a potential treatment target of metastatic CRC.

Nuciferine attenuates lipopolysaccharide-stimulated inflammatory responses by inhibiting p38 MAPK/ATF2 signaling pathways.

Nuciferine, isolated from Nelumbo nucifera (commonly known as lotus) leaves, has been shown to have beneficial effects, including antioxidant, anti-obesity, anti-diabetic, and anti-inflammatory properties. However, little is known about the mechanism of nuciferine action on the inflammatory response. This study aimed to investigate the anti-inflammatory effects of nuciferine and its underlying molecular mechanisms in lipopolysaccharide (LPS)-stimulated murine macrophages. In this study, nuciferine reduced LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production and mRNA expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2. Nuciferine also decreased the production of pro-inflammatory cytokines such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α. Furthermore, nuciferine inhibited the LPS-mediated transcriptional activity of nuclear factor (NF)-κB and activator protein (AP)-1, and the nuclear translocation of NF-κB p65 and activating transcription factor 2 (ATF2), an AP-1 subunit. Nuciferine also decreased the phosphorylation of IκB kinase (IKK), inhibitor of NF-κB (IκB), NF-κB, mitogen-activated protein kinase 3 (MKK3), MKK6, p38 mitogen-activated protein kinase (MAPK), and ATF2. Overall, our findings suggest that nuciferine may exert anti-inflammatory effects in LPS-induced macrophages by inhibiting the NF-κB and p38 MAPK/ATF2 signaling pathways.

Activating transcription factor 2 (AccATF2) regulates tolerance to oxidative stress in Apis cerana cerana.

Activating transcription factor 2 (ATF2), a basic leucine zipper (bZIP) transcription factor, plays a crucial role in immune and DNA damage response in mammals. However, the function of ATF2 in insects remains unknown. Here, we isolated the ATF2 gene from Apis cerana cerana (AccATF2) and found that AccATF2 was a main regulator of the honeybee response to oxidative stress. Our results showed that AccATF2 was highly expressed in the head, thorax and integument. AccATF2 was expressed throughout the development period of honeybees, and the highest AccATF2 transcript level was noted in brown-eyed pupae, indicating its indispensable roles in honeybee survival. Antioxidant function analysis showed that AccATF2 expression was markedly induced in response to oxidative stress caused by various environmental stresses. AccATF2 overexpression substantially enhanced the tolerance to oxidative stress of Escherichia coli cells compared with control cells. AccATF2 knockdown significantly increased the production of malondialdehyde (MDA), the transcription of antioxidant genes and the activity of antioxidant enzymes in honeybees, suggesting that AccATF2 knockdown resulted in oxidative damage to honeybees. Moreover, AccATF2 knockdown decreased honeybee resistance to oxidative stress caused by high temperature. Overall, AccATF2 plays an important role in maintaining redox homeostasis and protecting honeybees from oxidative stress caused by various environmental stimuli. Our discoveries add to a growing understanding of how honeybees cope with various adverse environmental conditions to ensure their survival.

lncRNA PINK1-AS Aggravates Cerebral Ischemia/Reperfusion Oxidative Stress Injury through Regulating ATF2 by Sponging miR-203.

Ischemic stroke is a common disease that led to high mortality and high disability. NADPH oxidase 2- (NOX2-) mediated oxidative stress and long noncoding RNA have important roles in cerebral ischemia/reperfusion (CI/R) injury, whereas whether there is interplay between them remains to be clarified. This study was performed to observe the role of lncRNA PINK1-antisense RNA (PINK1-AS) in NOX2 expression regulation. An in vivo rat model (MCAO) and an in vitro cell model (H/R: hypoxia/reoxygenation) were utilized for CI/R oxidative stress injury investigation. The expression levels of lncRNA PINK1-AS, activating transcription factor 2 (ATF2), NOX2, and caspase-3 and the production level of ROS and cell apoptosis were significantly increased in CI/R injury model rats or in H/R-induced SH-SY5Y cells, but miR-203 was significantly downregulated. There was positive correlation between PINK1-AS expression level and ROS production level. PINK1-AS and ATF2 were found to be putative targets of miR-203. Knockdown of lncRNA PINK1-AS or ATF2 or the overexpression of miR-203 significantly reduced oxidative stress injury via inhibition of NOX2. Overexpression of lncRNA PINK1 significantly led to oxidative stress injury in SH-SY5Y cells through downregulating miR-203 and upregulating ATF2 and NOX2. lncRNA PINK1-AS and ATF2 were the targets of miR-203, and the lncRNA PINK1-AS/miR-203/ATF2/NOX2 axis plays pivotal roles in CI/R injury. Therefore, lncRNA PINK1-AS is a possible target for CR/I injury therapy by sponging miR-203.

ATF2 loss promotes tumor invasion in colorectal cancer cells via upregulation of cancer driver TROP2.

In cancer, the activating transcription factor 2 (ATF2) has pleiotropic functions in cellular responses to growth stimuli, damage, or inflammation. Due to only limited studies, the significance of ATF2 in colorectal cancer (CRC) is not well understood. We report that low ATF2 levels correlated with worse prognosis and tumor aggressiveness in CRC patients. NanoString gene expression and ChIP analysis confirmed trophoblast cell surface antigen 2 (TROP2) as a novel inhibitory ATF2 target gene. This inverse correlation was further observed in primary human tumor tissues. Immunostainings revealed that high intratumoral heterogeneity for ATF2 and TROP2 expression was sustained also in liver metastasis. Mechanistically, our in vitro data of CRISPR/Cas9-generated ATF2 knockout (KO) clones revealed that high TROP2 levels were critical for cell de-adhesion and increased cell migration without triggering EMT. TROP2 was enriched in filopodia and displaced Paxillin from adherens junctions. In vivo imaging, micro-computer tomography, and immunostainings verified that an ATF2KO/TROP2high status triggered tumor invasiveness in in vivo mouse and chicken xenograft models. In silico analysis provided direct support that ATF2low/TROP2high expression status defined high-risk CRC patients. Finally, our data demonstrate that ATF2 acts as a tumor suppressor by inhibiting the cancer driver TROP2. Therapeutic TROP2 targeting might prevent particularly the first steps in metastasis, i.e., the de-adhesion and invasion of colon cancer cells.

ANKRD49 promotes the invasion and metastasis of lung adenocarcinoma via a P38/ATF-2 signalling pathway.

Lung adenocarcinoma (LUAD) is the most challenging neoplasm to treat in clinical practice. Ankyrin repeat domain 49 protein (ANKRD49) is highly expressed in several carcinomas; however, its pattern of expression and role in LUAD are not known. Tissue microarrays, immunohistochemistry, χ2 test, Spearman correlation analysis, Kaplan-Meier, log-rank test, and Cox's proportional hazard model were used to analyse the clinical cases. The effect of ANKRD49 on the LUAD was investigated using CCK-8, clonal formation, would healing, transwell assays, and nude mice experiment. Expressions of ANKRD49 and its associated downstream protein molecules were verified by real-time PCR, Western blot, immunohistochemistry, and/or immunofluorescence analyses. ANKRD49 expression was highly elevated in LUAD. The survival rate and Cox's modelling analysis indicated that there may be an independent prognostic indicator for LUAD patients. We also found that ANKRD49 promoted the invasion and migration in both in in vitro and in vivo assays, through upregulating matrix metalloproteinase (MMP)-2 and MMP-9 activities via the P38/ATF-2 signalling pathway Our findings suggest that ANKRD49 is a latent biomarker for evaluating LUAD prognosis and promotes the metastasis of A549 cells via upregulation of MMP-2 and MMP-9 in a P38/ATF-2 pathway-dependent manner.

Phospho-proteomics identifies a critical role of ATF2 in pseudorabies virus replication.

Pseudorabies virus (PRV), an etiological agent of pseudorabies in livestock, has negatively affected the porcine industry all over the world. Epithelial cells are reported as the first site of PRV infection. However, the role of host proteins and its related signaling pathways in PRV replication is largely unclear. In this study, we performed a quantitative phosphoproteomics screening on PRV-infected porcine kidney (PK-15) epithelial cells. Totally 5723 phosphopeptides, corresponding to 2180 proteins, were obtained, and the phosphorylated states of 810 proteins were significantly different in PRV-infected cells compared with mock-infected cells (P â€‹< â€‹0.05). GO and KEGG analysis revealed that these differentially expressed phosphorylated proteins were predominantly related to RNA transport and MAPK signaling pathways. Further functional studies of NF-κB, transcription activator factor-2 (ATF2), MAX and SOS genes in MAPK signaling pathway were analyzed using RNA interference (RNAi) knockdown. It showed that only ATF2-knockdown reduces both PRV titer and viral genome copy number. JNK pathway inhibition and CRISPR/Cas9 gene knockout showed that ATF2 was required for the effective replication of PRV, especially during the biogenesis of viral genome DNA. Subsequently, by overexpression of the ATF2 gene and point mutation of the amino acid positions 69/71 of ATF2, it was further demonstrated that the phosphorylation of ATF2 promoted PRV replication. These findings suggest that ATF2 may provide potential therapeutic target for inhibiting PRV infection.

Overexpression of Activating Transcription Factor-2 (ATF-2) Activates Wnt/Ca2+ Signaling Pathways and Promotes Proliferation and Invasion in Non-Small-Cell Lung Cancer.

Previous studies have suggested an association of the expression of activating transcription factor-2 (ATF-2) with the survival time and the activity of the Wnt/Ca2+ signaling pathway in non-small-cell lung cancer (NSCLC). However, the exact role of ATF-2 in tumorigenesis and its underlying mechanism remains unclear. In this study, we study whether ATF-2 regulates the growth and reproduction of NSCLC cells through the Wnt/Ca2+ pathway. The expression of ATF-2 and pathway-related genes in non-small-cell lung cancer was detected by qRT-PCR and Western blotting. CRISPR/Cas9 technology was used to knock out the ATF-2 gene, and pathway inhibitors and agonists were added to induce cultured cells. The expression of pathway genes and the proliferation and invasion ability of A549 lung cancer cells were analyzed. ATF-2 and pathway-related genes were upregulated in NSCLC. The proliferation and invasion ability of A549 lung cancer cells was decreased after only adding pathway inhibitors. The expression of Wnt/Ca2+ pathway protein was decreased when the ATF-2 gene was knocked out, but the expression of Wnt/Ca2+ pathway protein was reversed after the addition of a pathway agonist. These results suggest that ATF-2 acts as an agonist in the Wnt/Ca2+ signaling pathway, promoting the expression of Wnt5a, Wnt11, CaMK II, and NLK in the Wnt/Ca2+ pathway, thereby regulating the proliferation and invasion of NSCLC cells.

Adapalene induces adipose browning through the RARß-p38 MAPK-ATF2 pathway.

Adipose browning has recently been reported to be a novel therapeutic strategy for obesity. Because the retinoic acid receptor (RAR) is a potential target involved in browning, adapalene (AD), an anti-acne agent with RAR agonism, was examined in detail for its effects on adipose browning and the underlying mechanisms in vitro and in vivo. AD upregulated the expression of adipose browning-related markers in a concentration-dependent manner, promoted mitochondrial biogenesis, increased oxygen consumption rates, and lowered lipid droplet sizes in differentiated 3T3/L1 white adipocytes. Among the three retinoic acid receptors (RARα, RARß, and RARγ), knockdown of the gene encoding RARß mitigated AD-induced adipose browning. Similarly, LE135 (a selective RARß antagonist) attenuated AD action, suggesting that AD promotes adipose browning through RARß. Sequential phosphorylation of p38 mitogen-activated protein kinase (MAPK) and activating transcription factor 2 (ATF2) was critical for AD-induced adipose browning, based on the observations that either SB203580 (a p38 MAPK inhibitor) or ATF2 siRNA reduced the effects of AD. In vivo browning effects of AD were confirmed in C57BL/6J mice and high-fat diet-induced obese (DIO) mice after oral administration of AD either acutely or chronically. This study identifies new actions of AD as an adipose browning agent and demonstrates that RARß activation followed by increased phosphorylation of p38 MAPK and ATF2 appears to be a key mechanism of AD action.

CircFN1 upregulation initiated oxidative stress-induced apoptosis and inhibition of proliferation and migration in trophoblasts via circFN1-miR-19a/b-3p-ATF2 ceRNA network.

Recently, the etiopathogenesis of preeclampsia (PE) has been developed from the perspective of circular RNA, microRNA and their crosstalk in placental oxidative stress. Real-time quantitative PCR and western blotting detected expression of circular RNA-fibronectin 1 (circFN1; ID hsa_circ_0058152), microRNA (miR)-19a/b-3p and activating transcription factor 2 (ATF2). Receiver operating characteristic (ROC) curve analyzed the predictive value of circFN1. Oxidative stress, apoptosis, proliferation, and migration were measured using superoxide dismutase (SOD) and malonaldehyde (MDA) assay kits, Annexin V/Prodium iodide and western blotting methods, MTS and EdU assays, and scratch wound assay, respectively. Target relationships were retrieved by miRNA target prediction software and confirmed by dual-luciferase reporter assay, RNA immunoprecipitation and RNA pull-down. Expression of circFN1 was upregulated in the serum of PE pregnancies, and the area under the ROC curve of serum circFN1 was 0.7826 (95% confidence interval: 0.6495-0.9157; sensitivity 86.96%; specificity 56%). Functionally, its upregulation decreased SOD activity, cell viability, EdU incorporation, migration rate, and Bcl-2 expression in human trophoblast HTR-8/SV-neo cells, but meanwhile increased MDA level, apoptosis rate, and Bax and cleaved-caspase3 expression. Moreover, its downregulation played the opposite effects in HTR-8/SV-neo cells. Mechanistically, circFN1 functioned as "miRNA sponge" for miR-19a/b-3p and modulated the latter's target gene ATF2. There were feedback effects of miR-19a/b-3p restorations and ATF2 depletion on circFN1 actions in HTR-8/SV-neo cells. Oxidative injury-mediated placental trophoblast dysfunction in PE was through competing endogenous RNA (ceRNA) mechanism of CircFN1-miR-19a/b-3p-ATF2 axes.

CircRNF121 knockdown suppresses the progression of cervical cancer by regulating miR-153-3p/ATF2 axis and wnt/ß-catenin pathway.

Cervical cancer (CC) is a common malignancy in gynecology. Emerging evidence has demonstrated that circular RNAs (circRNAs) act as vital mediators in CC. However, the roles of circRNA ring finger protein 121 (circRNF121) in CC are largely unknown. Herein, we focused on the exact function and underlying mechanism of circRNF121 in CC development. Our results showed that circRNF121 was highly expressed in CC tissues and cells. Knockdown of circRNF121 suppressed cell growth, metastasis, epithelial-mesenchymal transition (EMT), autophagy, and wnt/ß-catenin pathway in CC cells in vitro and blocked tumor formation in vivo. For mechanism investigation, circRNF121 could affect activating transcription factor 2 (ATF2) expression by decoying miR-153-3p, thereby accelerating CC cell development. In conclusion, circRNF121 exerted the tumor-suppressive role in CC progression by altering miR-153-3p/ATF2 axis. These results suggested that circRNF121 might be a possible circ-targeted therapy for patients with CC.

Protein disulfide-isomerase A3 knockdown attenuates oxidized low-density lipoprotein-induced oxidative stress, inflammation and endothelial dysfunction in human umbilical vein endothelial cells by downregulating activating transcription factor 2.

Atherosclerosis is a chronic inflammatory disease implicated in oxidative stress and endothelial dysfunction. Protein disulfide-isomerase A3 (PDIA3) has been reported to regulate oxidative stress and suppress inflammation. This study aimed to explore the function of PDIA3 in atherosclerosis and the underlying mechanisms. PDIA3 expression in oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs) was detected using RT-qPCR and Western blotting. Following PDIA3 knockdown through transfection with small interfering RNA targeting PDIA3, cell viability, oxidative stress and inflammation in ox-LDL-induced HUVECs was examined using a Cell Counting Kit-8, corresponding kits and ELISA, respectively. The levels of CD31, α-smooth muscle, iNOS, p-eNOS, eNOS and NO were assessed using RT-qPCR, Western blotting and an NO kit to reflect endothelial dysfunction in ox-LDL-induced HUVECs. The relationship between PDIA3 and the activating transcription factor 2 (ATF2) was confirmed using co-immunoprecipitation. In addition, ATF2 expression was examined following PDIA3 silencing. The results indicated that PDIA3 was highly expressed in ox-LDL-induced HUVECs. PDIA3 silencing increased cell viability, and reduced oxidative stress and inflammation, as evidenced by the decreased levels of reactive oxygen species, malondialdehyde, TNF-α, IL-1ß and IL-6, and increased superoxide dismutase and glutathione peroxidase activity. In addition, PDIA3 deletion improved endothelial dysfunction. PDIA3 interacted with ATF2, and PDIA3 deletion downregulated ATF2 expression. Furthermore, ATF2 overexpression reversed the effects of PDIA3 knockdown on ox-LDL-induced damage of HUVECs. Collectively, PDIA3 knockdown was found to attenuate ox-LDL-induced oxidative stress, inflammation and endothelial dysfunction in HUVECs by downregulating ATF2 expression, showing promise for the future treatment of atherosclerosis.