The nuclear receptor NOR-1/NR4A3 regulates the multifunctional glycoprotein vitronectin in human vascular smooth muscle cells

Upregulation of NOR-1 in calcified human vascular tissues: impact on osteogenic differentiation and calcification

Cardiovascular calcification is a significant public health issue whose pathophysiology is not fully understood. NOR-1 regulates critical processes in cardiovascular remodeling, but its contribution to ectopic calcification is unknown. NOR-1 was overexpressed in human calcific aortic valves and calcified atherosclerotic lesions colocalizing with RUNX2, a factor essential for osteochondrogenic differentiation and calcification. NOR-1 and osteogenic markers were upregulated in calcifying human valvular interstitial cells (VICs) and human vascular smooth muscle cells (VSMCs). Gain- and loss-of-function approaches demonstrated that NOR-1 negatively modulates the expression of osteogenic genes relevant for the osteogenic transdifferentiation (RUNX2, IL-6, BMP2, and ALPL) and calcification of VICs. VSMCs from transgenic mice overexpressing NOR-1 in these cells (TgNOR-1VSMC) expressed lower basal levels of osteogenic genes (IL-6, BMP2, ALPL, OPN) than cells from WT littermates, and their upregulation by a high-phosphate osteogenic medium (OM) was completely prevented by NOR-1 transgenesis. Consistently, this was associated with a dramatic reduction in the calcification of both transgenic VSMCs and aortic rings from TgNOR-1VSMC mice exposed to OM. Atherosclerosis and calcification were induce in mice by the administration of AAV-PCSK9D374Y and a high-fat/high-cholesterol diet. Challenged-TgNOR-1VSMC mice exhibited decreased vascular expression of osteogenic markers, and both less atherosclerotic burden (assessed in whole aorta and lesion size in aortic arch and brachiocephalic artery) and less vascular calcification (assessed either by near-infrared fluorescence imaging or histological analysis) than WT mice. Our data indicate that NOR-1 negatively modulates the expression of genes critically involved in the osteogenic differentiation of VICs and VSMCs, thereby restraining ectopic cardiovascular calcification.

Apolipoprotein A-IV of diabetic-foot patients upregulates tumor necrosis factor α expression in microfluidic arterial models

Diabetic peripheral arterial atherosclerosis is one of the important characteristics of diabetic foot syndrome. Apolipoprotein (Apo A-IV) participates in various physiological processes, and animal studies have shown that it has roles of anti-atherosclerosis, prevention of platelet aggregation and thrombosis. Apo A-IV glycosylation is closely related to the occurrence and development of diabetic peripheral atherosclerosis. This study aimed to explore the mechanism of diabetic peripheral arterial lesions caused by glycosylated Apo A-IV. Type 2 diabetes mellitus (T2DM) and T2DM with diabetic foot patients (T2DM-F; n = 45, 30) were enrolled in this study, and individuals without diabetes (n = 35) served as normal controls (NC). In T2DM group, serum Apo A-IV content was higher than those in NC and T2DM-F group, as carboxymethyl lysine (CML) glycosylation of Apo A-IV in mixed serum from T2DM-F group was identified to be more significant than those in two other groups. Within a microfluidic arterial chip model, Apo A-IV from T2DM and T2DM-F group significantly increased transcription and protein levels of tumor necrosis factor alpha (TNF-α) in chip arteries, and CML expression was observed in T2DM-F group, which were associated with increased nuclear receptor subfamily 4 group A member 3 (NR4A3) expression. Recombinant human Apo A-IV could reverse the stimulating effect of serum Apo A-IV from T2DM-F group on TNF-α expression, and NR4A3 blocking peptide downregulated TNF-α expression by inhibiting NR4A3 expression. In the chip arteries, Apo A-IV from T2DM and T2DM-F increased TNF-α expression and turn them into a pre-atherosclerotic state, which might be one of the important mechanisms of glycosylated Apo A-IV to induce diabetic peripheral arterial lesions and eventually lead to diabetic foot.

Association of genetic variants in ULK4 with the age of first onset of type B aortic dissection

Background: The association between autophagy, structural alterations of the aortic wall, and endothelial dysfunction in humans has yet to be fully elucidated. The family of ULK (UNC51-like) enzymes plays critical roles in autophagy and development. This study aimed to evaluate the association between ULK gene family members and patient age of first type B aortic dissection (TBAD) onset.

Methods: The genotype data in a TBAD cohort from China and the related summary-level datasets were analyzed. We applied the sequence kernel association test (SKAT) to test the association between single-nucleotide polymorphisms (SNPs) and age of first onset of TBAD controlling for gender, hypertension, and renal function. Next, we performed a 2-sample Mendelian randomization (MR) to explore the potential causal relationship between ULK4 and early onset of TBAD at the level of gene expression coupled with DNA methylation with genetic variants as instrumental variables.

Results: A total of 159 TBAD patients with 1,180,097 SNPs were included. Concerning the association between the ULK gene family and the age of first onset of the TBAD, only ULK4 was found to be significant according to SKAT analysis (q-FDR = 0.0088). From 2-sample MR, the high level of ULK4 gene expression was related to a later age of first onset of TBAD (β = 4.58, p = 0.0214).

Conclusion: This is the first study of the ULK gene family in TBAD, regarding the association with the first onset age. We demonstrated that the ULK4 gene is associated with the time of onset of TBAD based on both the SKAT and 2-sample MR analyses.

Nuclear receptor NOR-1 (Neuron-derived Orphan Receptor-1) in pathological vascular remodelling and vascular remodelling

Vascular cells and their interaction with inflammatory cells and the immune system play a key role in pathological vascular remodeling. A large number of genes and proteins regulated in a coordinated manner by a small number of transcription factors are involved in this process. In recent years, research on a small subfamily of transcription factors, the NR4A subfamily, has had a major impact on our understanding of vascular biology. The NR4A1 (Nur77), NR4A2 (Nurr1) and NR4A3 (NOR-1) receptors are products of early response genes whose expression is induced by multiple pathophysiological and physical stimuli. Their wide distribution in different tissues and cells places them in the control of numerous processes such as cell differentiation, proliferation, survival and apoptosis, as well as inflammation and the metabolism of lipids and carbohydrates. This review analyzes the role of these receptors, particularly NOR-1, in pathological vascular remodeling associated with atherosclerosis, abdominal aortic aneurysm and pulmonary arterial hypertension.

MiR-34a-3p suppresses pulmonary vascular proliferation in acute pulmonary embolism rat by targeting DUSP1

BACKGROUND

Acute pulmonary embolism (APE) is a prevalent reason of cardiovascular morbidity and mortality. Recent studies have underscored the positive effects of microRNAs (miRNAs) on many diseases. The present study aimed to identify the critical miRNA with differential expressions and explore its role in APE.

METHODS

The critical miRNA with its target gene was screened by bioinformatics analysis. Their binding relationship was analyzed by TargetScan, Dual-luciferase reporter and RNA pull-down assays. A rat model of APE was established by self-blood coagulum. Human pulmonary artery smooth muscle cells (PASMCs) were exposed to platelet-derived growth factor (PDGF-BB) for excessive proliferation, and transfected with miR-34a-3p mimic. Mean pulmonary arterial pressure (mPAP) of rat was measured, and the pulmonary tissues were used for the pathological observation by Hematoxylin-Eosin (H&E) staining. Cell viability and proliferation were detected by Cell Counting Kit-8 (CCK-8) and EdU assays. The expressions of miR-34a-3p with its target genes (including dual-specificity phosphatase-1 (DUSP1)), neuron-derived orphan receptor-1 (NOR-1) and proliferating cell nuclear antigen (PCNA) were determined by quantitative reverse transcription polymerase chain reaction (RT-qPCR) or/and Western blot.

RESULTS

MiR-34a-3p expression was down-regulated in APE patients, which attenuated the increment of mPAP and thickening of the pulmonary arterial walls in APE rats, accompanied with regulation of NOR-1 and PCNA levels. MiR-34a-3p suppressed DUSP1 expression by directly binding to its 3'-untranslated region (UTR), and attenuated cell viability, proliferation, and the expressions of NOR-1 and PCNA in PDGF-BB-induced PASMCs by inhibiting DUSP1 expression.

CONCLUSION

Up-regulated miR-34a-3p negatively regulates DUSP1 expression to inhibit PASMC proliferation, which, thus, may act on APE treatment by negatively regulating pulmonary vascular proliferation.

NR4A3: A Key Nuclear Receptor in Vascular Biology, Cardiovascular Remodeling, and Beyond

The mechanisms committed in the activation and response of vascular and inflammatory immune cells play a major role in tissue remodeling in cardiovascular diseases (CVDs) such as atherosclerosis, pulmonary arterial hypertension, and abdominal aortic aneurysm. Cardiovascular remodeling entails interrelated cellular processes (proliferation, survival/apoptosis, inflammation, extracellular matrix (ECM) synthesis/degradation, redox homeostasis, etc.) coordinately regulated by a reduced number of transcription factors. Nuclear receptors of the subfamily 4 group A (NR4A) have recently emerged as key master genes in multiple cellular processes and vital functions of different organs, and have been involved in a variety of high-incidence human pathologies including atherosclerosis and other CVDs. This paper reviews the major findings involving NR4A3 (Neuron-derived Orphan Receptor 1, NOR-1) in the cardiovascular remodeling operating in these diseases.

Tumor Nonimmune-Microenvironment-Related Gene Expression Signature Predicts Brain Metastasis in Lung Adenocarcinoma Patients after Surgery: A Machine Learning Approach Using Gene Expression Profiling

Simple Summary

It is important to be able to predict brain metastasis in lung adenocarcinoma patients; however, research in this area is still lacking. Much of the previous work on tumor microenvironments in lung adenocarcinoma with brain metastasis concerns the tumor immune microenvironment. The importance of the tumor nonimmune microenvironment (extracellular matrix (ECM), epithelial–mesenchymal transition (EMT) feature, and angiogenesis) has been overlooked with regard to brain metastasis. We evaluated tumor nonimmune-microenvironment-related gene expression signatures that could predict brain metastasis after the surgical resection of lung adenocarcinoma using a machine learning approach. We identified a tumor nonimmune-microenvironment-related 17-gene expression signature, and this signature showed high brain metastasis predictive power in four machine learning classifiers. The immunohistochemical expression of the top three genes of the 17-gene expression signature yielded similar results to NanoString tests. Our tumor nonimmune-microenvironment-related gene expression signatures are important biological markers that can predict brain metastasis and provide patient-specific treatment options.

Abstract

Using a machine learning approach with a gene expression profile, we discovered a tumor nonimmune-microenvironment-related gene expression signature, including extracellular matrix (ECM) remodeling, epithelial–mesenchymal transition (EMT), and angiogenesis, that could predict brain metastasis (BM) after the surgical resection of 64 lung adenocarcinomas (LUAD). Gene expression profiling identified a tumor nonimmune-microenvironment-related 17-gene expression signature that significantly correlated with BM. Of the 17 genes, 11 were ECM-remodeling-related genes. The 17-gene expression signature showed high BM predictive power in four machine learning classifiers (areas under the receiver operating characteristic curve = 0.845 for naïve Bayes, 0.849 for support vector machine, 0.858 for random forest, and 0.839 for neural network). Subgroup analysis revealed that the BM predictive power of the 17-gene signature was higher in the early-stage LUAD than in the late-stage LUAD. Pathway enrichment analysis showed that the upregulated differentially expressed genes were mainly enriched in the ECM–receptor interaction pathway. The immunohistochemical expression of the top three genes of the 17-gene expression signature yielded similar results to NanoString tests. The tumor nonimmune-microenvironment-related gene expression signatures found in this study are important biological markers that can predict BM and provide patient-specific treatment options.

Renin Cell Baroreceptor, a Nuclear Mechanotransducer Central for Homeostasis

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Temporomandibular Disorders Slow Down the Regeneration Process of Masticatory Muscles: Transcriptomic Analysis

Background and Objectives: Musculoskeletal injuries represent a pathological condition due to limited joint motility and morphological and functional alterations of the muscles. Temporomandibular disorders (TMDs) are pathological conditions due to alterations in the musculoskeletal system. TMDs mainly cause temporomandibular joint and masticatory muscle dysfunctions following trauma, along with various pathologies and inflammatory processes. TMD affects approximately 15% of the population and causes malocclusion problems and common symptoms such as myofascial pain and migraine. The aim of this work was to provide a transcriptomic profile of masticatory muscles obtained from TMD migraine patients compared to control. Materials and Methods: We used Next Generation Sequencing (NGS) technology to evaluate transcriptomes in masseter and temporalis muscle samples. Results: The transcriptomic analysis showed a prevalent downregulation of the genes involved in the myogenesis process. Conclusions: In conclusion, our findings suggest that the muscle regeneration process in TMD migraine patients may be slowed, therefore therapeutic interventions are needed to restore temporomandibular joint function and promote healing processes.

High NOR-1 (Neuron-Derived Orphan Receptor 1) Expression Strengthens the Vascular Wall Response to Angiotensin II Leading to Aneurysm Formation in Mice

No drug therapy has shown to limit abdominal aortic aneurysm (AAA) growth or rupture, and the understanding of the disease biology is incomplete; whereby, one challenge of vascular medicine is the development of good animal models and therapies for this life-threatening condition. The nuclear receptor NOR-1 (neuron-derived orphan receptor 1) controls biological processes involved in AAA; however, whether it plays a role in this pathology is unknown. Through a gain-of-function approach we assessed the impact of NOR-1 expression on the vascular response to Ang II (angiotensin II). We used 2 mouse models that overexpress human NOR-1 in the vasculature, one of them specifically in vascular smooth muscle cells. NOR-1 transgenesis amplifies the response to Ang II enhancing vascular inflammation (production of proinflammatory cytokines, chemokines, and reactive oxygen species), increasing MMP (matrix metalloproteinase) activity and disturbing elastin integrity, thereby broking the resistance of C57BL/6 mice to Ang II-induced AAA. Genes encoding for proteins critically involved in AAA formation (Il [interleukin]-6, Il-1β, Cxcl2, [C-X-C motif chemokine ligand 2], Mcp-1 [monocyte chemoattractant protein 1], and Mmp2) were upregulated in aneurysmal tissues. Both animal models show a similar incidence and severity of AAA, suggesting that high expression of NOR-1 in vascular smooth muscle cell is a sufficient condition to strengthen the response to Ang II. These alterations, including AAA formation, were prevented by the MMP inhibitor doxycycline. Microarray analysis identified gene sets that could explain the susceptibility of transgenic animals to Ang II-induced aneurysms, including those related with extracellular matrix remodeling, inflammatory/immune response, sympathetic activity, and vascular smooth muscle cell differentiation. These results involve NOR-1 in AAA and validate mice overexpressing this receptor as useful experimental models.

Neuron-derived orphan receptor-1 modulates cardiac gene expression and exacerbates angiotensin II-induced cardiac hypertrophy

Hypertensive cardiac hypertrophy (HCH) is a common cause of heart failure (HF), a major public health problem worldwide. However, the molecular bases of HCH have not been completely elucidated. Neuron-derived orphan receptor-1 (NOR-1) is a nuclear receptor whose role in cardiac remodelling is poorly understood. The aim of the present study was to generate a transgenic mouse over-expressing NOR-1 in the heart (TgNOR-1) and assess the impact of this gain-of-function on HCH. The CAG promoter-driven transgenesis led to viable animals that over-expressed NOR-1 in the heart, mainly in cardiomyocytes and also in cardiofibroblasts. Cardiomyocytes from TgNOR-1 exhibited an enhanced cell surface area and myosin heavy chain 7 (Myh7)/Myh6 expression ratio, and increased cell shortening elicited by electric field stimulation. TgNOR-1 cardiofibroblasts expressed higher levels of myofibroblast markers than wild-type (WT) cells (α 1 skeletal muscle actin (Acta1), transgelin (Sm22α)) and were more prone to synthesise collagen and migrate. TgNOR-1 mice experienced an age-associated remodelling of the left ventricle (LV). Angiotensin II (AngII) induced the cardiac expression of NOR-1, and NOR-1 transgenesis exacerbated AngII-induced cardiac hypertrophy and fibrosis. This effect was associated with the up-regulation of hypertrophic (brain natriuretic peptide (Bnp), Acta1 and Myh7) and fibrotic markers (collagen type I α 1 chain (Col1a1), Pai-1 and lysyl oxidase-like 2 (Loxl2)). NOR-1 transgenesis up-regulated two key genes involved in cardiac hypertrophy (Myh7, encoding for β-myosin heavy chain (β-MHC)) and fibrosis (Loxl2, encoding for the extracellular matrix (ECM) modifying enzyme, Loxl2). Interestigly, in transient transfection assays, NOR-1 drove the transcription of Myh7 and Loxl2 promoters. Our findings suggest that NOR-1 is involved in the transcriptional programme leading to HCH.

miR‑106b‑5p modulates acute pulmonary embolism via NOR1 in pulmonary artery smooth muscle cells

Acute pulmonary embolism (APE) is a common cause of acute cardiovascular failure and has a high morbidity and mortality rate. Inhibiting the excessive proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) is a potential treatment strategy following an APE. Various microRNAs (miRNAs/miRs) have been shown to regulate cell proliferation, apoptosis and other physiological processes. However, the specific mechanisms underlying the action of multiple miRNAs are still not understood in APE. In the present study, the role of miR‑106b‑5p on APE was demonstrated in platelet‑derived growth factor (PDGF)‑induced PASMCs in vitro and in an APE‑mouse model in vivo. The results showed that miR‑106b‑5p expression was downregulated in PDGF‑induced PASMCs and APE mice, and NOR1 levels were upregulated. Proliferating cell nuclear antigen (PCNA) expression levels in cells and proliferation of PASMCs proliferation and migration were reduced following treatment with miR‑106b‑5p agomiR, and increased following treatment with miR‑106b‑5p antagomiR. miR‑106b‑5p targeted the 3' untranslated region of NOR‑1 mRNA and reduced NOR1 expression. NOR1 overexpression reversed the effects of miR‑106‑5p on PDGF‑induced PASMCs. The functional roles of miR‑106b‑5p in PDGF‑induced PASMCs and an APE mouse‑model, and the underlying molecular mechanisms were evaluated. AgomiR‑106b‑5p improved APE‑induced mortality and pulmonary vascular proliferation in mice. These data suggest that miR‑106‑5p is a novel regulator of proliferation of PASMCs and of pulmonary vascular remodeling through PDGF‑induced PASMCs in an APE mouse model via targeting NOR1. These results expand the understanding of the pathogenesis underlying APE and highlight potential novel therapeutic targets.

The pro-inflammatory effect of NR4A3 in osteoarthritis

NR4A3 is a member of nuclear receptor subfamily 4, which is an important regulator of cellular function and inflammation. In this study, high expression of NR4A3 in human osteoarthritis (OA) cartilage was firstly observed. To explore the relationship between NR4A3 and OA, we used a lentivirus overexpression system to simulate its high expression and study its role in OA. Additionally, siRNA-mediated knockdown of NR4A3 was used to confirm the findings of overexpression experiments. The results showed the stimulatory effect of IL-1β on cartilage matrix-degrading enzyme expression such as MMP-3, 9, INOS and COX-2 was enhanced in NR4A3-overexpressed chondrocytes and decreased in NR4A3-knockdown chondrocytes at both mRNA and protein levels, while IL-1β-induced chondrocyte-specific gene (collagen 2 and SOX-9) degradation was only regulated by NR4A3 at protein level. Furthermore, overexpression of NR4A3 would also enhance EBSS-induced chondrocytes apoptosis, while knockdown of NR4A3 decreased apoptotic level after EBSS treatment. A pathway study indicated that IL-1β-induced NF-κB activation was enhanced by NR4A3 overexpression and reduced by NR4A3 knockdown. We suggest that NR4A3 plays a pro-inflammatory role in the development of OA, and we also speculate that NR4A3 mainly regulates cartilage matrix-degrading gene expression under inflammatory conditions via the NF-κB pathway.

miR-665 expression predicts poor survival and promotes tumor metastasis by targeting NR4A3 in breast cancer

Cancer metastasis is the main cause of death in breast cancer (BC) patients. Therefore, prediction and treatment of metastasis is critical for enhancing the survival of BC patients. In this study, we aimed to identify biomarkers that can predict metastasis of BC and elucidate the underlying mechanism of the functional involvement of such markers in metastasis. miRNA expression profile was analyzed using a custom microarray system in 422 BC tissues. The relationship between the upregulated miR-665, metastasis and survival of BC was analyzed and verified in another set of 161 BC samples. The biological function of miR-665 in BC carcinogenesis was explored with in vitro and in vivo methods. The target gene of miR-665 and its signaling cascade were also analyzed. There are 399 differentially expressed miRNAs between BC and noncancerous tissues, of which miR-665 is the most upregulated miRNA in the BC tissues compared with non-tumor breast tissues (P < 0.001). The expression of miR-665 predicts metastasis and poor survival in 422 BC patients, which is verified in another 161 BC patients and 2323 BC cases from online databases. Ectopic miR-665 expression promotes epithelial–mesenchymal transition (EMT), proliferation, migration and invasion of BC cells, and increases tumor growth and metastasis of BC in mice. Bioinformatics, luciferase assay and other methods showed that nuclear receptor subfamily 4 group A member 3 (NR4A3) is a target of miR-665 in BC. Mechanistically, we demonstrated that miR-665 promotes EMT, invasion and metastasis of BC via inhibiting NR4A3 to activate MAPK/ERK kinase (MEK) signaling pathway. Our study demonstrates that miR-665 upregulation is associated with metastasis and poor survival in BC patients, and mechanistically, miR-665 enhances progression of BC via NR4A3/MEK signaling pathway. This study provides a new potential prognostic biomarker and therapeutic target for BC patients.

Enhancer hijacking activates oncogenic transcription factor NR4A3 in acinic cell carcinomas of the salivary glands

The molecular pathogenesis of salivary gland acinic cell carcinoma (AciCC) is poorly understood. The secretory Ca-binding phosphoprotein (SCPP) gene cluster at 4q13 encodes structurally related phosphoproteins of which some are specifically expressed at high levels in the salivary glands and constitute major components of saliva. Here we report on recurrent rearrangements [t(4;9)(q13;q31)] in AciCC that translocate active enhancer regions from the SCPP gene cluster to the region upstream of Nuclear Receptor Subfamily 4 Group A Member 3 (NR4A3) at 9q31. We show that NR4A3 is specifically upregulated in AciCCs, and that active chromatin regions and gene expression signatures in AciCCs are highly correlated with the NR4A3 transcription factor binding motif. Overexpression of NR4A3 in mouse salivary gland cells increases expression of known NR4A3 target genes and has a stimulatory functional effect on cell proliferation. We conclude that NR4A3 is upregulated through enhancer hijacking and has important oncogenic functions in AciCC.

The nuclear receptor NOR-1 modulates redox homeostasis in human vascular smooth muscle cells

The nuclear receptor NOR-1 (Neuron-derived Orphan Receptor-1) has recently been involved in vascular remodeling and coronary artery disease, however, to date, only a few NOR-1 target genes have been described. We aimed to identify genes regulated by NOR-1 in human vascular smooth muscle cells (VSMC). Lentiviral overexpression of NOR-1 increases reactive oxygen species (ROS) in human VSMC. In accordance, NOR-1 strongly increased NADPH oxidase NOX1 mRNA and protein levels, while NOR-1 silencing significantly reduced NOX1 expression. Luciferase reporter, site-directed mutagenesis and EMSA studies identified two nerve growth factor-induced clone B (NGFI-B)-response elements (NBREs) in NOX1 promoter as essential elements for NOR-1 responsiveness. NOR-1 and NOX1 were co-expressed by VSMC in human atherosclerotic lesions, and NOX1 knockdown counteracted the increased ROS production and cell migration induced by NOR-1 overexpression. NOR-1 also modulated the expression of other enzymes involved in cellular redox status, in particular, upregulated superoxide dismutase-1 (SOD1) and SOD3 while downregulated SOD2 and NOX4. NOR-1 induced SOD1 and SOD3 transcriptional activity and participated in the modulation of SOD3 by inflammatory stimuli. By contrast, NOR-1 impaired SOD2 transcription antagonizing NFκB signaling. These results indicate that NOR-1 induces NOX1 in human VSMC and participates in the complex gene networks regulating oxidative stress and redox homeostasis in the vasculature.