Nuclear Receptor Subfamily Research Articles

The Diagnostic Features of Peripheral Blood Biomarkers in Identifying Osteoarthritis Individuals: Machine Learning Strategies and Clinical Evidence.

People with osteoarthritis place a huge burden on society. Early diagnosis is essential to prevent disease progression and to select the best treatment strategy more effectively. In this study, the aim was to examine the diagnostic features and clinical value of peripheral blood biomarkers for osteoarthritis. The goal of this project was to investigate the diagnostic features of peripheral blood and immune cell infiltration in osteoarthritis (OA). Two eligible datasets (GSE63359 and GSE48556) were obtained from the GEO database to discern differentially expressed genes (DEGs). The machine learning strategy was employed to filtrate diagnostic biomarkers for OA. Additional verification was implemented by collecting clinical samples of OA. The CIBERSORT website estimated relative subsets of RNA transcripts to evaluate the immune-inflammatory states of OA. The link between specific DEGs and clinical immune-inflammatory markers was found by correlation analysis. Overall, 67 robust DEGs were identified. The nuclear receptor subfamily 2 group C member 2 (NR2C2), transcription factor 4 (TCF4), stromal antigen 1 (STAG1), and interleukin 18 receptor accessory protein (IL18RAP) were identified as effective diagnostic markers of OA in peripheral blood. All four diagnostic markers showed significant increases in expression in OA. Analysis of immune cell infiltration revealed that macrophages are involved in the occurrence of OA. Candidate diagnostic markers were correlated with clinical immune-inflammatory indicators of OA patients. We highlight that DEGs associated with immune inflammation (NR2C2, TCF4, STAG1, and IL18RAP) may be potential biomarkers for peripheral blood in OA, which are also associated with clinical immune-inflammatory indicators.

Nuclear receptor subfamily 4 group a member 1 eases angiotensin II-arose oxidative stress in vascular smooth muscle cell by boosting nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 3 transcription

Objective: Hypertension significantly contributes to morbidity and mortality. Nuclear receptor subfamily 4 group a member 1 (Nur77) participates in regulating oxidative stress, but the mechanism in hypertension remains unclear. This study aimed to explore the function of Nur77 in oxidative stress induced by Angiotensin II (Ang II) in vascular smooth muscle cells (VSMCs) in hypertension. Material and Methods: First, models of VSMC with Nur77, nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 3 (NLRC3) and tumor necrosis factor receptor-associated factor 6 (TRAF6) knockdown or overexpression were constructed using Short Hairpin RNA (Nur77) or pcDNA3.1 vector, respectively. Next, the putative-binding motifs between Nur77 and NLRC3 promoters were detected by dual luciferase assay. We conducted reverse transcription quantitative polymerase chain reaction (qPCR) and Western blot (WB) analysis to detect Nur77, NLRC3, and TRAF6 levels in VSMCs. Then, cell counting kit-8 assay, 5-ethynyl-2’-deoxyuridine assay, wound-healing assay, enzyme-linked immunosorbent assay, and 2’,7’-dichlorofluorescin diacetate were employed to examine the impact of the knockdown or overexpression of Nur77, NLRC3, and TRAF6 on VSMCs treated with Ang II. The assays measured cell viability and proliferation, cell migration, malondialdehyde levels, and reactive oxygen species levels. Results: The overexpression of Nur77 repressed cell growth (P < 0.001), migration (P < 0.01), and oxidative stress (P < 0.01) induced by Ang II in VSMCs. Nur77 transcriptionally promoted the expression of NLRC3 (P < 0.001), and the upregulation of NLRC3 suppressed cell proliferation (P < 0.05) and oxidative stress (P < 0.001) mediated by Ang II. Furthermore, NLRC3 negatively regulated the TRAF6/nuclear factor-kappa B (NF-κB) axis activated by Ang II, which resulted in the repression of hyperproliferation of VSMCs (P < 0.01) and oxidative stress (P < 0.001). Conclusion: Nur77 suppressed growth and oxidative stress induced by Ang II in VSMCs by promoting NLRC3 transcription, which, further, repressed the TRAF6/NF-κB axis. This understanding provides novel insights into the pathogenesis of hypertension.

Transcriptome analysis identifies the NR4A subfamily involved in the alleviating effect of folic acid on mastitis induced by high concentration of Staphylococcus aureus lipoteichoic acid

BackgroundStaphylococcus aureus (S. aureus) mastitis results in economic losses during dairy production. Understanding the biological progression of bovine S. aureus mastitis is vital for its prevention. Lipoteichoic acid is a key virulence factor of S. aureus (aLTA), but the main biological pathways involved in its effect on bovine mammary epithetionallial cells (Mac-T) apoptosis and necrosis have not been fully explored. Folic acid (FA) has anti-inflammatory and anti-apoptotic effects. However, the role of FA in mediating the effects of aLTA on apoptosis and necrosis remains unknown.ResultsWe found that low concentration of aLTA inhibited apoptosis and necrosis and that high concentration promoted the apoptosis and necrosis of Mac-T. FA pretreatment alleviated high concentration of aLTA induced apoptosis. Through transcriptomic analysis, we found that nuclear receptor subfamily 4 group A (NR4A), which alters the expression of downstream genes involved in apoptosis, proliferation, and inflammation, decreased under stimulation with a low concentration of aLTA and increased under stimulation with a high concentration of aLTA. Under stimulation with a high concentration of aLTA, the expression of the NR4A subfamily could be inhibited by FA. The results showed that aLTA may affect apoptosis and necrosis through the NR4A subfamily by targeting genes involved in bacterial invasion of epithelial cells, the IL-17 signaling pathway, DNA replication, longevity regulation, the cell cycle, and tight junction pathways. We further found that the expression trends of NR4A1 and the target genes of the NR4A subfamily (PTGS2, ESPL1, MCM5, and BUB1B) in the blood of healthy cows (Healthy), subclinical mastitis cows (SCM), and SCM supplemented with FA (SCM_FA) were consistent with those observed at the cellular level in this study.ConclusionsOur study revealed that low and high concentrations of aLTA have opposite effects on apoptosis and necrosis of Mac-T and that FA can alleviate the apoptosis induced by high concentration of aLTA. Transcriptome analysis revealed that the NR4A subfamily play a role in the ability of FA to alleviate the apoptosis and necrosis induced by high concentration of aLTA.

Nr1d1 inhibition mitigates intermittent hypoxia-induced pulmonary hypertension via Dusp1-mediated Erk1/2 deactivation and mitochondrial fission attenuation

Intermittent hypoxia (IH) precipitates pulmonary vasoconstriction, culminating in the onset of pulmonary hypertension (PH) among individuals afflicted with sleep apnea. While Nuclear receptor subfamily 1 group D member 1 (Nr1d1) is progressively recognized as pivotal regulator of cellular physiology, the role in the pathogenesis of IH-induced PH remains largely uncharted. The expression of Nr1d1 was examined in IH-induced rodent PH and in IH-treated PASMCs. To elucidate the contribution of Nr1d1 to the development of IH-induced PH, we employed siRNA to modulate Nr1d1 expression in vitro and employed serotype 1 adeno-associated virus (AAV1) in vivo. Nr1d1 levels were elevated in IH-induced rodents PH lung tissues and IH-treated PASMCs. Knocking down Nr1d1 by AAV1 effectively inhibited PH progression in chronic IH-induced PH models. Mechanistic investigations identified dual specificity phosphatase 1 (Dusp1), as a direct target that Nr1d1 trans-repressed, mediating Nr1d1’s regulatory influence on Erk1/2/Drp1 signaling. Nr1d1 deficiency ameliorates mitochondrial dysfunction and fission by restoring Dusp1 dysregulation and Drp1 phosphorylation. Activation of Erk1/2 with PMA reversed the Dusp1-mediated regulation of Drp1 phosphorylation, indicating the involvement of the Erk1/2 pathway in Drp1 phosphorylation controlled by Dusp1. Meanwhile, intermittent hypoxia induced more severe PH in Dusp1 knockout mice compared with wild-type mice. Our data unveil a novel role for Nr1d1 in IH-induced PH pathogenesis and an undisclosed Nr1d1-Dusp1 axis in PASMCs mitochondrial fission regulation.

Investigating the role of an orphan nuclear receptor NR4A1 in atrial fibrillation

Abstract Introduction Atrial fibrosis is a major remodelling process in atrial fibrillation (AF). The lack of clinically effective drug targets, due to insufficient understanding of the mechanisms of cardiac fibrosis, hampers the treatment of AF. Orphan nuclear receptor subfamily 4 group A member 1 (NR4A1) is linked to fibrotic disease in multiple organs, however, its role in cardiac fibrosis and AF is yet to be demonstrated. Recent transcriptomic profiling revealed that NR4A1 expression is downregulated in human atrial cardiac fibroblasts (ACFs) in the presence of persistent AF. However, its mechanistic role in atrial fibrogenesis and AF is unknown. Purpose To investigate the expression profile and function of NR4A1 in human ACFs and provide insights into the role of NR4A1 in the context of persistent AF. Methods Human ACFs were isolated (enzymatic digestion) from right and left atrial appendages of 24 patients with persistent AF and controls in sinus rhythm (SR), who had elective heart surgery. NR4A1 knockdown in ACFs was achieved using NR4A1-siRNA. Gene and protein expression were determined by qPCR and western blot respectively, while BrdU assay and scratch assay were used to evaluate cell proliferation and migration. Atrial fibroblasts subpopulations were identified by single-nucleus RNA-sequencing. Subcellular localisation of NR4A1 was assessed by immunostaining, analysed by ImageJ. Results Validation of RNA-sequencing data confirmed a reduction of NR4A1 gene expression in human ACFs in persistent AF by 25% (p=0.029, Fig. 1A) and the NR4A1 predominant abundance in one of three identified subclusters of human ACFs (NR4A1+NAMPT+). The siRNA-mediated knockdown of NR4A1 in ACFs suppressed gene and protein expression of important component of extracellular matrix collagen-1 (Fig. 1B and Fig. 1C) and fibronectin protein (but not mRNA). The NR4A1-deficient cells also had decreased alpha-smooth muscle actin (αSMA) protein and gene expression (Fig. 1D and Fig. 1E), reduced periostin gene expression in the absence of changes in its protein. Furthermore, the NR4A1-deficiency reduced proliferation (by 18%, p=0.005, Fig. 1F) and accelerated migration (p=0.019, Fig. 1G) of human ACFs. These effects were independent of TGF-β1 stimulation, unlike reported in rat neonatal cardiac and dermal fibroblasts. Despite decreased NR4A1 gene expression, patients with AF had doubled NR4A1 protein levels compared to SR-ACFs (p=0.049, Fig. 2A). This was associated with abnormal 1.8-fold increase in the receptor subcellular localisation (p=0.032, Fig. 2B and Fig. 2C), as opposed to the physiological nuclear localisation observed in ACFs in the absence of AF. Conclusion While under physiological conditions, NR4A1 potently activates profibrotic processes in human ACFs, persistent AF patients have increased but abnormally distributed NR4A1 protein in atrial fibroblasts, whose consequences are yet to be determined in order to develop new therapies for AF.Figure 1Figure 2

Dexmedetomidine Ameliorates Myocardial Ischemia-Reperfusion Injury by Inhibiting MDH2 Lactylation via Regulating Metabolic Reprogramming.

Myocardial ischemia-reperfusion injury (MIRI) significantly worsens the outcomes of patients with cardiovascular diseases. Dexmedetomidine (Dex) is recognized for its cardioprotective properties, but the related mechanisms, especially regarding metabolic reprogramming, have not been fully clarified. A total of 60 patients with heart valve disease are randomly assigned to Dex or control group. Blood samples are collected to analyze cardiac injury biomarkers and metabolomics. In vivo and vitro rat models of MIRI are utilized to assess the effects of Dex on cardiac function, lactate production, and mitochondrial function. It is found that postoperative CK-MB and cTNT levels are significantly lower in the Dex group. Metabolomics reveals that Dex regulates metabolic reprogramming and reduces lactate level. In Dex-treated rats, the myocardial infarction area is reduced, and myocardial contractility is improved. Dex inhibits glycolysis, reduces lactate, and improves mitochondrial function following MIRI. Lactylation proteomics identifies that Dex reduces the lactylation of Malate Dehydrogenase 2（MDH2), thus alleviating myocardial injury. Further studies reveal that MDH2 lactylation induces ferroptosis, leading to MIRI by impairing mitochondrial function. Mechanistic analyses reveal that Dex upregulates Nuclear Receptor Subfamily 3 Group C Member 1（NR3C1)phosphorylation, downregulates Pyruvate Dehydrogenase Kinase 4 (PDK4), and reduces lactate production and MDH2 lactylation. These findings provide new therapeutic targets and mechanisms for the treatment for MIRI.

Roles of NR1I3 and NR1H4 polymorphisms in the susceptibility to antituberculosis drug-induced liver injury in China: a case‒control study.

The pathogenesis of antituberculosis drug-induced liver injury (AT-DILI) remains largely unknown. The current investigation aimed to determine the genetic contribution of the nuclear receptor subfamily 1 Group I member 3 (NR1I3) and nuclear receptor subfamily 1 Group H member 4 (NR1H4) genes to the risk of AT-DILI in the Chinese population. A 1:4 matched case‒control study was conducted, and five single nucleotide polymorphisms (SNPs) in the NR1I3 and NR1H4 genes were detected and assessed. Utilizing a multivariate conditional logistic regression model, the effects of haplotype and genotype on the risk of AT-DILI were examined. Extended subgroup analysis was carried out based on sex. The distribution of the peak value of serum liver enzymes also compared among different genotypes. 224 AT-DILI cases and 896 controls were included in this study. No significant difference was observed in genotypes or haplotypes frequencies between AT-DILI cases and controls. However, comparisons of liver function indicators revealed significant differences in the peak values of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBil) among patients with different genotypes of NR1H4 rs56163822 (GG vs. GT vs. TT, 27.1 U/L vs. 26.0 U/L vs. 23.0 U/L, p = 0.020; 34.0 U/L vs. 31.0 U/L vs. 30.6 U/L, p = 0.008; 15.5μmol/L vs. 15.0μmol/L vs. 13.7μmol/L, p = 0.029, respectively), as well as in the peak values of ALT and AST among male patients with different genotypes of NR1H4 rs56163822 (29.0 U/L vs. 26.9 U/L vs. 22.6 U/L, p = 0.002; 34.0 U/L vs. 32.0 U/L vs. 30.5 U/L, p = 0.019, respectively). Based on this 1:4 individual-matched case‒control study, the SNP rs56163822 in the NR1H4 gene may be linked to the susceptibility to AT-DILI in Chinese patients receiving anti-TB treatment. Further studies in larger varied populations are needed to validate our findings.

Hepatocyte-specific NR5A2 deficiency induces pyroptosis and exacerbates non-alcoholic steatohepatitis by downregulating ALDH1B1 expression

Nonalcoholic steatohepatitis (NASH) is a prevalent chronic disease, yet its exact mechanisms and effective treatments remain elusive. Nuclear receptor subfamily 5 group A member 2 (NR5A2), a transcription factor closely associated with cholesterol metabolism in the liver, has been hindered from comprehensive investigation due to the lethality of NR5A2 loss in cell lines and animal models. To elucidate the role of NR5A2 in NASH, we generated hepatocyte-specific knockout mice for Nr5a2 (Nr5a2HKO) and examined their liver morphology across different age groups under a regular diet. Furthermore, we established cell lines expressing haploid levels of NR5A2 and subsequently reintroduced various isoforms of NR5A2. In the liver of Nr5a2HKO mice, inflammation and fibrosis spontaneously emerged from an early age, independent of lipid accumulation. Pyroptosis occurred in NR5A2-deficient cell lines, and different isoforms of NR5A2 reversed this form of cell death. Our findings unveiled that inhibition of NR5A2 triggers pyroptosis, a proinflammatory mode of cell death primarily mediated by the activation of the NF-κB pathway induced by reactive oxygen species (ROS). As a transcriptionally regulated molecule of NR5A2, aldehyde dehydrogenase 1 family member B1 (ALDH1B1) participates in pyroptosis through modulation of ROS level. In conclusion, the diverse isoforms of NR5A2 exert hepatoprotective effects against NASH by maintaining a finely tuned balance of ROS, which is contingent upon the activity of ALDH1B1.

The Role of Retinoic-Acid-Related Orphan Receptor (RORs) in Cellular Homeostasis.

Retinoic-acid-related orphan receptors (RORs) are transcription factors belonging to the nuclear receptor subfamily consisting of RORα, RORβ, and RORγ. By binding to the ROR response elements (ROREs) on target gene promoters, RORs regulate a wide variety of cellular processes, including autophagy, mitophagy, oxidative stress, and inflammation. The regulatory roles of RORs are observed in cardiac cells, hepatocytes, pulmonary epithelial cells, renal cells, immune cells, and cancer cells. A growing body of clinical and experimental evidence suggests that ROR expression levels are markedly reduced under different pathological and stress conditions, suggesting that RORs may play a critical role in the pathogenesis of a variety of disease states, including myocardial infarction, immune disorders, cancer, and metabolic syndrome. Reductions in RORs are also associated with inhibition of autophagy, increased reactive oxygen species (ROS), and increased cell death, underscoring the importance of RORs in the regulation of these processes. Herein, we highlight the relationship between RORs and homeostatic processes that influence cell viability. Understanding how these intricate processes are governed at the cellular level is of high scientific and clinical importance to develop new therapeutic strategies that modulate ROR expression and disease progression.

Orphan nuclear receptor NR4A1 regulates both osteoblastogenesis and adipogenesis in human mesenchymal stem cells.

The nuclear receptor subfamily 4 group A member 1 (NR4A1) gene plays a crucial role in both osteoporosis and adipogenesis. The present study investigated the mechanisms by which NR4A1 influences osteoblastogenesis and adipogenesis in human bone marrow‑derived mesenchymal stem cells (BMD‑MSCs). NR4A1 was overexpressed or knocked down in mouse MC3T3‑E1 osteoblast cells and 3T3‑L1 adipocyte cells, as well as in PCS‑500‑012, a BMD‑MSC line. The alkaline phosphatase (ALP) assay and Alizarin Red S staining were performed using MC3T3‑E1 and BMD‑MSCs to assess ALP activity and mineralization, while Oil Red O staining was used to assess the lipid content in 3T3‑L1 cells and BMD‑MSCs. Total RNA was isolated from control, NR4A1‑overexpressing and NR4A1 small interfering RNA (siRNA; siNR4A1)‑treated BMD‑MSCs. RNA sequencing (RNA‑seq) was performed to identify differentially expressed genes, followed by ingenuity pathway analysis (IPA) to determine the role of NR4A1 in osteoblastogenesis and adipogenesis. NR4A1 or Nr4a1 knockdown tended to increase ALP activity and significantly increased calcification in BMD‑MSCs (P<0.005) and MC3T3‑E1 cells (P<0.005), respectively. By contrast, NR4A1 or Nr4a1 overexpression significantly decreased ALP activity and calcification. NR4A1 or Nr4a1 knockdown and overexpression significantly decreased and increased adipogenesis, respectively, in BMD‑MSCs (P<0.005 and <0.05, respectively) and 3T3‑L1 cells (P<0.005 in both). Treatments of BMD‑MSCs with an NR4A1 antagonist, 1,1‑bis(3'‑indolyl)‑1‑(p‑hydroxyphenyl) methane and siNR4A1 showed similar results. RNA‑seq and IPA in control, NR4A1 knockdown and NR4A1 overexpressing cells indicated that Notch signaling mediated the effects of NR4A1 in osteoblastogenesis and adipogenesis. Expression of mastermind‑like transcriptional coactivator 3 was reduced in the Notch signaling pathway in cells treated with siNR4A1. In conclusion, NR4A1 suppressed osteoblastogenesis and promotes adipogenesis in human BMD‑MSCs. The present study also suggested that NR4A1 plays a role in the progression of osteoporosis and adipogenesis by modulating the Notch signaling cascade.

The impact of mineralocorticoid and glucocorticoid receptor interaction on corticosteroid transcriptional outcomes

The mineralocorticoid and glucocorticoid receptors (MR and GR, respectively) are members of the steroid receptor subfamily of nuclear receptors. Their main function is to act as ligand-activated transcription factors, transducing the effects of corticosteroid hormones (aldosterone and glucocorticoids) by modulating gene expression. Corticosteroid signaling is essential for homeostasis and adaptation to different forms of stress. GR responds to glucocorticoids by regulating genes involved in development, metabolism, immunomodulation and brain function. MR is best known for mediating the effects of aldosterone, a key hormone controlling electrolyte and water homeostasis. In addition to aldosterone, MR binds glucocorticoids (cortisol and corticosterone) with equally high affinity. This ligand promiscuity has important repercussions to understand MR function, as well as glucocorticoid signaling. MR and GR share significant sequence and structural similarities, regulate overlapping sets of genes and are able to interact forming heteromeric complexes. However, the precise role of these heteromers in regulating corticosteroid-regulated transcriptional outcomes remains an open question. In this review, we examine the evidence supporting MR-GR heteromerization, the molecular determinants of complex formation and their possible role in differential regulation of transcription in different cellular contexts and ligand availability.

Proteogenomic Landscape of Breast Ductal Carcinoma Reveals Tumor Progression Characteristics and Therapeutic Targets.

Multi-omics studies of breast ductal carcinoma (BRDC) have advanced the understanding of the disease's biology and accelerated targeted therapies. However, the temporal order of a series of biological events in the progression of BRDC is still poorly understood. A comprehensive proteogenomic analysis of 224 samples from 168 patients with malignant and benign breast diseases is carried out. Proteogenomic analysis reveals the characteristics of linear multi-step progression of BRDC, such as tumor protein P53 (TP53) mutation-associated estrogen receptor 1 (ESR1) overexpression is involved in the transition from ductal hyperplasia (DH) to ductal carcinoma in situ (DCIS). 6q21 amplification-associated nuclear receptor subfamily 3 group C member 1 (NR3C1) overexpression helps DCIS_Pure (pure DCIS, no histologic evidence of invasion) cells avoid immune destruction. The T-cell lymphoma invasion and metastasis 1, androgen receptor, and aldo-keto reductase family 1 member C1 (TIAM1-AR-AKR1C1) axis promotes cell invasion and migration in DCIS_adjIDC (DCIS regions of invasive cancers). In addition, AKR1C1 is identified as a potential therapeutic target and demonstrated the inhibitory effect of aspirin and dydrogesterone as its inhibitors on tumor cells. The integrative multi-omics analysis helps to understand the progression of BRDC and provides an opportunity to treat BRDC in different stages.

Differential roles of NR4A2 (NURR1) paralogs in the brain and behavior of zebrafish.

Dopaminergic (DAnergic) dysfunction and imbalanced dopamine (DA) levels are known contributors to the pathogenesis of numerous psychiatric and neurodegenerative disorders. Of the many identified risk factors for DA-associated disorders, nuclear receptor subfamily 4 group A2 (NR4A2; or nuclear receptor related-1 protein (NURR1)), a transcription factor involved in DAnergic differentiation, has been associated with Parkinson's disease and attention deficit hyperactive disorder (ADHD). In zebrafish, transient loss of nr4a2 was previously shown to decrease tyrosine hydroxylase (TH) expression and impair locomotion. To further characterize the roles of the two zebrafish nr4a2 paralogs, nr4a2a, and nr4a2b, we produced targeted loss-of-function mutants and examined DAnergic neuron regeneration, oxidative respiration, and behavioral traits. The loss of nr4a2a function more closely recapitulated Parkinsonian phenotypes and affected neurotrophic factor gene expression. Conversely, nr4a2b mutants displayed behavioral symptoms reminiscent of mice deficient in Nr4a2 with increased neurotrophic output. In contrast, nr4a2b mutants also displayed increased metabolic input from non-mitochondrial sources indicative of high cytosolic reactive oxygen species and perturbed mitochondrial function. The nr4a2a mutants also showed increased maximal respiration, which may suggest a compensatory mechanism to meet the metabolic requirements of DAnergic neuron health. Overall, the zebrafish mutants generated in this study helped uncover molecular mechanisms involved in DA-related disease pathologies, and in the regeneration of DAnergic neurons.

Functional inversion of circadian regulator REV-ERBα leads to tumorigenic gene reprogramming

Profound functional switch of key regulatory factors may play a major role in homeostasis and disease. Dysregulation of circadian rhythm (CR) is strongly implicated in cancer with mechanisms poorly understood. We report here that the function of REV-ERBα, a major CR regulator of the orphan nuclear receptor subfamily, is dramatically altered in tumors in both its genome binding and functional mode. Loss of CR is linked to a functional inversion of REV-ERBα from a repressor in control of CR and metabolic gene programs in normal tissues to a strong activator in different cancers. Through changing its association from NCoR/HDAC3 corepressor complex to BRD4/p300 coactivators, REV-ERBα directly activates thousands of genes including tumorigenic programs such as MAPK and PI3K-Akt signaling. Functioning as a master transcriptional activator, REV-ERBα partners with pioneer factor FOXA1 and directly stimulates a large number of signaling genes, including multiple growth factors, receptor tyrosine kinases, RASs, AKTs, and MAPKs. Moreover, elevated REV-ERBα reprograms FOXA1 to bind new targets through a BRD4-mediated increase in local chromatin accessibility. Pharmacological targeting with SR8278 diminishes the function of both REV-ERBα and FOXA1 and synergizes with BRD4 inhibitor in effective suppression of tumorigenic programs and tumor growth. Thus, our study revealed a functional inversion by a CR regulator in driving gene reprogramming as an unexpected paradigm of tumorigenesis mechanism and demonstrated a high effectiveness of therapeutic targeting such switch.

Brief research report: Transcriptional blockade of angiotensin converting enzyme 2 modelled in human retinal pigment epithelial cells

As a key host protein involved in cellular infection by the severe acute respiratory syndrome coronavirus (SARS-CoV-2), angiotensin converting enzyme (ACE)2 is an ideal target for antiviral drugs. Manipulation of transcription provides opportunity for graduated blockade that preserves physiological functions. We sought to develop a model system for evaluating manipulation of ACE2 gene transcription using human retinal pigment epithelium. Retinal pigment epithelial cell isolates were prepared from human posterior eyecups (n = 11 individual isolates). The cells expressed ACE2 transcript and protein, and expression was not induced by hypoxia mimetic dimethyloxaloylglycine, or inflammatory cytokine IL-1β. ACE2 gene transcription factors were predicted in silico and cross-referenced with the human retinal pigment epithelial cell transcriptome, and five candidate transcription factors were identified: ETS proto-oncogene 1 transcription factor (ETS1), nuclear factor I C (NFIC), nuclear receptor subfamily 2 group C member 1 (NR2C1), TEA domain transcription factor 1 (TEAD1), and zinc finger protein 384 (ZNF384). The candidates were individually targeted in cells by transfection with small interfering (si)RNA. Knockdowns reduced mean cellular expression of all the transcription factors in comparison to expression in cells transfected with control non-targeted siRNA. Mean cellular ACE2 transcript was reduced under the condition of NR2C1 knockdown, but not for ETS1, NFIC, TEAD1, and ZNF384 knockdowns. Our findings build on previous work demonstrating the potential for drugging gene transcription. Importantly, we show the value of human retinal pigment epithelium as a system for evaluating ACE2 transcriptional blockade, a possible approach for treating SARS-CoV-2 infection. Brief Research Report.

6371 Conditional Deletion Of Nr5a1 In Sox9-cre Mice Impairs Adrenal Development

Abstract Disclosure: Y. Ikeda: None. A. Tagami: None. K. Ishizuka: None. M. Maekawa: None. The adrenal cortex is a major tissue that produces steroidogenic hormones necessary for regulating body homeostasis. Nuclear receptor subfamily 5, group A, member 1 (Nr5a1, SF-1, or Ad4BP) plays a crucial role in the regulation of adrenal and gonadal development, function and maintenance. SRY-related HMG-box gene 9 (Sox9) is upregulated by interaction of SRY with NR5A1, and leads the supporting cell precursors in XY gonads to differentiate into Sertoli-lineage cells at the initiation of testis differentiation. We previously generated Sox9-cre-Nr5a1flox/flox conditional knockout (cKO) mice, and showed that the loss of Nr5a1 in the gonads of XY Sox9-cre-Nr5a1flox/flox cKO mice abrogated the testicular pathway at embryonic day (E) 12.5–E13.5 to result in postnatal male-to-female gonadal sex reversal (1). Here, we investigated adrenal development of the Sox9-cre-Nr5a1flox/flox cKO mice. In mammals, after separation from the common adrenogonadal primordium, the adrenal primordium, which is formed dorsomedial to the gonadal primordium, begins to develop around E11.5. Double-immunostaining for NR5A1 and SOX9 revealed the presence of cells expressing both NR5A1 and SOX9 in the adrenal primordium of both sexes at E11.5 but not at E12.5. At E12.5, the number of NR5A1+ adrenocortical cells in Sox9-cre-Nr5a1flox/flox cKO mice markedly decreased compared with Nr5a1+/+ mice, and apoptotic cells, which were immunolabelled for active caspase 3, were detected in the area of the adrenal primordium in Sox9-cre-Nr5a1flox/flox cKO mice but not in Nr5a1+/+ mice, indicating that NR5A1- and SOX9-immunoreactive adrenocortical cells in Sox9-cre-Nr5a1flox/flox cKO mice were extinguished by apoptosis due to the activation of the Sox9-cre transgene. At E13.5–postnatal day 20, Sox9-cre-Nr5a1flox/flox cKO adrenals were hypoplastic associated with reduced number of NR5A1-immunoreactive adrenocortical cells, and only a few medullary cells immunolabelled for tyrosine hydroxylase, a marker of chromaffin cell precursors, were infiltrated into the adrenal primordium. Our findings suggest that sufficient number of adrenal cortical progenitors at the earliest stage of adrenal development are required for the subsequent adrenal development. In 8-week-old, Sox9-cre-Nr5a1flox/flox cKO adrenals were smaller in size compared with Nr5a1+/+ adrenals, but showed relatively normal organization with the medulla surrounded by the cortex. However, unlike XY Nr5a1+/+ adrenals, cells immunolabelled for the X-zone marker 20αHSD were observed at the junction between the cortex and medulla in XY Sox9-cre-Nr5a1flox/flox cKO adrenals, probably due to the sex reversal of the XY gonads, since androgen induces regression of the X-zone. Reference: (1) Ikeda et al., Sci Rep. 2021 Feb 24;11(1):4486. Presentation: 6/2/2024

Construction of a novel platelet‑related gene risk model to predict the prognosis and drug response in virus‑related hepatocellular carcinoma.

Platelet activity in the tumor microenvironment (TME) is crucial for the development of tumors. However, the roles and clinical potential of platelet activity in the TME for virus-related hepatocellular carcinoma (HCC) remain unclear. The present study aimed to identify a novel signature based on platelet activity for prognostic prediction and treatment decisions in virus-related HCC. First, a novel platelet signature score (PSS) for each patient with virus-related HCC from The Cancer Genome Atlas was calculated using gene set variation analysis, and the patients were divided into two subgroups (high and low PSS). It was demonstrated that the patients with a high PSS had a worse prognosis, higher platelet activity, stronger inflammation and immunosuppression in TME than patients with a low PSS. Furthermore, 137 differentially expressed genes (DEGs; fold change >2; P<0.05) were identified using 'DESeq2' and 'edgeR' software. Subsequently, 3 genes (cyclin-J-Like protein, nuclear receptor subfamily 0 group B member 1 and tripartite motif containing 54) were identified from DEGs using univariate Cox and least absolute shrinkage and selection operator (LASSO) analyses. Risk score (RS) was calculated based on gene expression and coefficients from LASSO. Patients were divided into high and low RS groups according to the median value, and the 3-gene model was used to predict prognoses and drug responses. Notably, it was demonstrated that patients with a low RS may be better candidates for immune therapy due to lower levels of tumor immune dysfunction and exclusion scores. Moreover, patients with a high RS may be better candidates for nonimmune therapy due to lower half-maximal inhibitory concentration values of drugs (such as AKT inhibitors and gemcitabine). Finally, it was demonstrated that patients with a high PSS and RS had a higher platelet activity, inflammation status, tumor hallmarks and the worst prognosis than patients with a low PSS and RS. This helped to better find patients with these characteristics and suitable treatments using this method. Collectively, the findings of the present study indicate that PSS combined with RS has great potential to evaluate the prognosis of patients with virus -related HCC and assist in deciding treatment strategies.

Loss of Nr4a1 ameliorates endothelial cell injury and vascular leakage in lung transplantation from circulatory-death donor

BackgroundIschemia-reperfusion injury (IRI) stands as a major trigger for primary graft dysfunction (PGD) in lung transplantation (LTx). Especially in LTx from donation after cardiac death (DCD), effective control of IRI following warm ischemia (WIRI) is crucial to prevent PGD. This study aimed to identify the key factors affecting WIRI in LTx from DCD. MethodsPreviously reported RNA-sequencing dataset of lung WIRI was reanalyzed to identify nuclear receptor subfamily 4 group A member 1 (NR4A1) as the immediate early gene for WIRI. Dynamics of NR4A1 expression were verified using a mouse hilar clamp model. To investigate the role of NR4A1 in WIRI, a mouse model of LTx from DCD was established using Nr4a1 knockout (Nr4a1-/-) mice. ResultsNR4A1 was located around vascular cells, and its protein levels in the lungs increased rapidly and transiently during WIRI. LTｘ from Nr4a1-/- donors significantly improved pulmonary graft function compared to wild-type donors (P < 0.001). Histological analysis showed decreased microvascular endothelial cell death (P = 0.007), neutrophil infiltration (P < 0.001), and albumin leakage (P < 0.001). Evans blue permeability assay demonstrated maintained pulmonary microvascular barrier integrity in grafts from Nr4a1-/- donors, correlating with diminished pulmonary edema (P < 0.001). However, NR4A1 did not significantly affect the inflammatory response during WIRI, and IRI was not suppressed when a wild-type donor lung was transplanted into the Nr4a1-/- recipient. ConclusionsDonor NR4A1 plays a specialized role in the positive regulation of endothelial cell injury and microvascular hyperpermeability. These findings demonstrate the potential of targeting NR4A1 interventions to alleviate PGD and improve outcomes in LTx from DCD.

BTN3A1 expressed in cervical cancer cells promotes Vγ9Vδ2 T cells exhaustion through upregulating transcription factors NR4A2/3 downstream of TCR signaling

BackgroundClinical trials have shown that immunotherapy based on Vγ9Vδ2 T cells (Vδ2 T cells) is safe and well-tolerated for various cancers including cervical cancer (CC), but its overall treatment efficacy remains limited. Therefore, exploring the mechanisms underlying the suboptimal efficacy of Vδ2 T cell-based cancer immunotherapy is crucial for enabling its successful clinical translation.MethodsTumor samples from CC patients and CC cell line-derived xenograft (CDX) mice were analyzed using flow cytometry to examine the exhausted phenotype of tumor-infiltrating Vδ2 T cells. The interrelationship between BTN3A1 expression and Vδ2 T cells in CC, along with their correlation with patient prognosis, was analyzed using data from The Cancer Genome Atlas (TCGA) database. CC cell lines with BTN3A1 knockout (KO) and overexpression (OE) were constructed through lentivirus transduction, which were then co-cultured with expanded Vδ2 T cells, followed by detecting the function of Vδ2 T cells using flow cytometry. The pathways and transcription factors (TFs) related to BTN3A1-induced Vδ2 T cells exhaustion and the factors affecting BTN3A1 expression were identified by RNA-seq analysis, which was confirmed by flow cytometry, Western Blot, and gene manipulation.ResultsTumor-infiltrating Vδ2 T cells exhibited an exhausted phenotype in both CC patients and CDX mice. BTN3A1 expressed in CC is highly enhancing exhaustion markers, while reducing the secretion of effector molecules in Vδ2 T cells. Blocking TCR or knocking down nuclear receptor subfamily 4 group A (NR4A) 2/3 can reverse BTN3A1-induced exhaustion in Vδ2 T cells. On the other hand, IFN-γ secreted by Vδ2 T cells promoted the expression of BTN3A1 and PD-L1.ConclusionsThrough binding γδ TCRs, BTN3A1 expressed on tumor cells, which is induced by IFN-γ, can promote Vδ2 T cells to upregulate the expression of TFs NR4A2/3, thereby affecting their activation and expression of exhaustion-related molecules in the tumor microenvironment (TME). Therefore, targeting BTN3A1 might overcome the immunosuppressive effect of the TME on Vδ2 T cells in CC.

Triptolide-induced acute liver injury and its mechanism with estradiol in regulating macrophage-mediated inflammation and hepatocyte function

Triptolide (TP), a diterpene from Tripterygium wilfordii, exhibits potent anti-inflammatory, immunomodulatory, and antitumor properties but is limited by severe hepatotoxicity. This study investigates sex differences in TP-induced liver injury and the protective role of estradiol (E2) in modulating macrophage-mediated inflammation and hepatocyte function. An acute liver injury model was established in male and female Balb/c mice using intraperitoneal TP injection. Liver function tests, histological analyses, and immunohistochemical staining were performed. THP-1 macrophage and various liver cell lines were used to study the effects of TP and E2 in vitro. Virtual screening, molecular docking, luciferase assays, and qPCR were employed to identify potential targets and elucidate underlying mechanisms. TP caused more severe liver injury in female mice, evidenced by increased liver indices, aspartate aminotransferase (AST) levels, and extensive hepatocyte damage. TP promoted M1 macrophage polarization, enhancing inflammation, particularly in female mice. E2 mitigated TP-induced inflammatory responses by downregulating pro-inflammatory cytokines and macrophage activation markers. Molecular docking and functional assays identified Nuclear receptor subfamily 1 group I member 2 (NR1I2) as a key target mediating the protective effects of E2. The study highlights significant sex differences in TP-induced hepatotoxicity, with females being more susceptible. E2 exerts protective effects against TP-induced liver injury by modulating immune responses, presenting a potential therapeutic approach to mitigate drug-induced liver injury (DILI). Further research on NR1I2 could lead to targeted therapies for reducing drug-induced liver damage.