ERRα Expression Research Articles

RBBP6-Mediated ERRα Degradation Contributes to Mitochondrial Injury in Renal Tubular Cells in Diabetic Kidney Disease.

Diabetic Kidney Disease (DKD), a major precursor to end-stage renal disease, involves mitochondrial dysfunction in proximal renal tubular cells (PTCs), contributing to its pathogenesis. Estrogen-related receptor α (ERRα) is essential for mitochondrial integrity in PTCs, yet its regulation in DKD is poorly understood. This study investigates ERRα expression and its regulatory mechanisms in DKD, assessing its therapeutic potential. Using genetic, biochemical, and cellular approaches, ERRα expression Was examined in human DKD specimens and DKD mouse models. We identified the E3 ubiquitin ligase retinoblastoma binding protein 6 (RBBP6) as a regulator of ERRα, promoting its degradation through K48-linked polyubiquitination at the K100 residue. This degradation pathway significantly contributed to mitochondrial injury in PTCs of DKD models. Notably, conditional ERRα overexpression or RBBP6 inhibition markedly reduced mitochondrial damage in diabetic mice, highlighting ERRα's protective role in maintaining mitochondrial integrity. The interaction between RBBP6 and ERRα opens new therapeutic avenues, suggesting that modulating RBBP6-ERRα interactions could be a strategy for preserving mitochondrial function and slowing DKD progression.

Estrogen-Related Receptor α: A Key Transcription Factor in the Regulation of Energy Metabolism at an Organismic Level and a Target of the ABA/LANCL Hormone Receptor System.

The orphan nuclear receptor ERRα is the most extensively researched member of the estrogen-related receptor family and holds a pivotal role in various functions associated with energy metabolism, especially in tissues characterized by high energy requirements, such as the heart, skeletal muscle, adipose tissue, kidney, and brain. Abscisic acid (ABA), traditionally acknowledged as a plant stress hormone, is detected and actively functions in organisms beyond the land plant kingdom, encompassing cyanobacteria, fungi, algae, protozoan parasites, lower Metazoa, and mammals. Its ancient, cross-kingdom role enables ABA and its signaling pathway to regulate cell responses to environmental stimuli in various organisms, such as marine sponges, higher plants, and humans. Recent advancements in understanding the physiological function of ABA and its mammalian receptors in governing energy metabolism and mitochondrial function in myocytes, adipocytes, and neuronal cells suggest potential therapeutic applications for ABA in pre-diabetes, diabetes, and cardio-/neuroprotection. The ABA/LANCL1-2 hormone/receptor system emerges as a novel regulator of ERRα expression levels and transcriptional activity, mediated through the AMPK/SIRT1/PGC-1α axis. There exists a reciprocal feed-forward transcriptional relationship between the LANCL proteins and transcriptional coactivators ERRα/PGC-1α, which may be leveraged using natural or synthetic LANCL agonists to enhance mitochondrial function across various clinical contexts.

Deciphering the Impact of Rare Missense Variants in EGFR-TKI-Resistant Non-Small-Cell Lung Cancer through Whole Exome Sequencing: A Computational Approach.

Targeted therapy revolutionizes the treatment of non-small-cell lung cancer (NSCLC), harboring molecular change. Epidermal growth factor receptor(EGFR) mutations play a crucial role in the development of NSCLC, serving as a pivotal factor in its pathogenesis. We elucidated the mechanisms of resistance and potential therapeutic strategies in NSCLC resistant to the EGFR-tyrosine kinase inhibitor (EGFR-TKI). This is achieved by identifying rare missense variants through whole exome sequencing (WES). The goal is to enhance our understanding, identify biomarkers, and lay the groundwork for targeted interventions, thereby offering hope for an improved NSCLC treatment landscape. We conducted WES analysis on 16 NSCLC samples with EGFR-TKI-resistant NSCLC obtained from SRA-NCBI (PRJEB50602) to reveal genomic profiles within the EGFR-TKI. Our findings showed that 48% of the variants were missense, and after filtering with the Ensembl variant effect predictor, 53 rare missense variants in 23 genes were identified as highly deleterious. Further examination using pathogenic tools like PredictSNP revealed 12 deleterious rare missense variants in 7 genes: ZNF717, PSPH, ESRRA, SEMA3G, PTPN7, CAVIN4, and MYBBP1A. Molecular dynamics simulation (MDS) suggested that the L385P variant alters the structural flexibility of ESRRA, potentially leading to unfolding of ERRα proteins. This could impact their function and alter ERRα expression. These insights from MDS enhance our understanding of the structural and dynamic consequences of the L385P ESRRA variant and provide valuable implications for subsequent therapeutic considerations and targeted interventions.

The Protective Effects of Syringic Acid on Bisphenol A-Induced Neurotoxicity Possibly Through AMPK/PGC-1α/Fndc5 and CREB/BDNF Signaling Pathways.

Bisphenol A (BPA), an endocrine disruptor, is commonly used to produce epoxy resins and polycarbonate plastics. Continuous exposure to BPA may contribute to the development of diseases in humans and seriously affect their health. Previous research suggests a significant relationship between the increased incidence of neurological diseases and the level of BPA in the living environment. Syringic acid (SA), a natural derivative of gallic acid, has recently considered much attention due to neuromodulator activity and its anti-oxidant, anti-apoptotic, and anti-inflammatory effects. Therefore, in this study, we aimed to investigate the effects of SA on oxidative stress, apoptosis, memory and locomotor disorders, and mitochondrial function, and to identify the mechanisms related to Alzheimer's disease (AD) in the brain of rats receiving high doses of BPA. For this purpose, male Wistar rats received BPA (50, 100, and 200mg/kg) and SA (50mg/kg) for 21days. The results showed that BPA exposure significantly altered the rats' neurobehavioral responses. Additionally, BPA, by increasing the level of ROS, and MDA level, increased the level of oxidative stress while reducing the level of antioxidant enzymes, such as SOD, CAT, GPx, and mitochondrial GSH. The administration of BPA at 200mg/kg significantly decreased the expression of ERRα, TFAM, irisin, PGC-1α, Bcl-2, and FNDC5, while it increased the expression of TrkB, cytochrome C, caspase 3, and Bax. Moreover, the Western blotting results showed that BPA increased the levels of P-AMPK, GSK3b, p-tau, and Aβ, while it decreased the levels of PKA, P-PKA, Akt, BDNF, CREB, P-CREB, and PI3K. Meanwhile, SA at 50mg/kg reversed the behavioral, biochemical, and molecular changes induced by high doses of BPA. Overall, BPA could lead to the development of AD by affecting the mitochondria-dependent apoptosis pathway, as well as AMPK/PGC-1α/FNDC5 and CREB/BDNF/TrkB signaling pathways, and finally, by increasing the expression of tau and Aβ proteins. In conclusion, SA, as an antioxidant, significantly reduced the toxicity of BPA.

ERRα regulates synaptic transmission through reactive oxygen species in hippocampal neurons

Reactive oxygen species (ROS) play multiple roles in synaptic transmission, and estrogen-related receptor α (ERRα) is involved in regulating ROS production. The purpose of our study was to explore the underlying effect of ERRα on ROS production, neurite formation and synaptic transmission. Our results revealed that knocking down ERRα expression affected the formation of neuronal neurites and dendritic spines, which are the basic structures of synaptic transmission and play important roles in learning, memory and neuronal plasticity; moreover, the amplitude and frequency of miniature excitatory postsynaptic currents (mEPSCs) and miniature inhibitory postsynaptic currents (mIPSCs) were decreased. These abnormalities were reversed by overexpression of human ERRα. Additionally, we also found that knocking down ERRα expression increased intracellular ROS levels in neurons. ROS inhibitor PBN rescued the changes in neurite formation and synaptic transmission induced by ERRα knockdown. These results indicate a new possible cellular mechanism by which ERRα affects intracellular ROS levels, which in turn regulate neurite and dendritic spine formation and synaptic transmission.

Advances in Medicinal Chemistry of Estrogen-related receptor alpha (ERRα) inverse agonists.

Estrogen-related receptor alpha (ERRα), a member of the nuclear receptor superfamily, is strongly expressed in breast cancer cells. Its overexpression is associated with poor prognosis in triple-negative breast cancer (TNBC). ERRα expression could be inhibited by the downregulation of upstream oncogenic growth factors mTOR, HER2, and PI3K. Low expression of ERRα could suppress the migration and angiogenesis of tumor cells by inhibiting the activity of its downstream signals VEGF and WNT11. Studies have confirmed that ERRα inverse agonists can inhibit ERRα expression to treat breast cancer. Inverse agonists of ERRα could disrupt the interactions of ERRα with its coactivators and inhibit tumor development. Existing ERRα inverse agonists have shown moderate efficacy in inhibiting the growth of breast cancer cells. Clinical inverse agonists of ERRα have not been found in the literature. This review focuses on the research progress and the structure-activity relationship of ERRα inverse agonists, providing guidance for the research and discovery of new anti-tumor compounds for TNBC.

ERRα protects against sepsis-induced acute lung injury in rats

BackgroundSepsis-induced acute lung injury (ALI) is associated with poor survival rates. The identification of potential therapeutic targets for preventing sepsis-induced ALI has clinical importance. This study aims to investigate the role of estrogen-related receptor alpha (ERRα) in sepsis-induced ALI.MethodsLipopolysaccharide (LPS) was used to simulate sepsis-induced ALI model in rat pulmonary microvascular endothelial cells (PMVECs). The effects of ERRα overexpression and knockdown on LPS-induced endothelial permeability, apoptosis and autophagy were determined by horseradish peroxidase permeability assay, TdT-mediated dUTP Nick End Labeling (TUNEL) assay, flow cytometry, immunofluorescence staining, RT-PCR and Western Blotting. The rat model with sepsis-induced ALI was established by cecal ligation and puncture in anesthetized rats to verify the results of in vitro experiments. Animals were randomly assigned to receive intraperitoneal injection of vehicle or ERRα agonist. Lung vascular permeability, pathological injury, apoptosis and autophagy were examined.ResultsOverexpression of ERRα ameliorated LPS-induced endothelial hyperpermeability, degradation of adherens junctional molecules, upregulation of bax, cleaved caspase 3 and cleaved caspase 9 levels, downregulation of anti-apoptotic protein Bcl-2 level, and promoted the formation of autophagic flux, while the knockdown of ERRα exacerbated LPS-induced apoptosis and inhibited the activation of autophagy. Administration of ERRα agonist alleviated the pathological damage of lung tissue, increased the levels of tight junction proteins and adherens junction proteins, and decreased the expression of apoptosis-related proteins. Promoting the expression of ERRα significantly enhanced the process of autophagy and reduced CLP-induced ALI. Mechanistically, ERRα is essential to regulate the balance between autophagy and apoptosis to maintain the adherens junctional integrity.ConclusionERRα protects against sepsis-induced ALI through ERRα-mediated apoptosis and autophagy. Activation of ERRα provides a new therapeutic opportunity to prevent sepsis-induced ALI.

Korean Red Ginseng-Induced SIRT3 Promotes the Tom22-HIF-1α Circuit in Normoxic Astrocytes.

Astrocytes play a key role in brain functioning by providing energy to neurons. Increased astrocytic mitochondrial functions by Korean red ginseng extract (KRGE) have been investigated in previous studies. KRGE administration induces hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in astrocytes in the adult mouse brain cortex. VEGF expression can be controlled by transcription factors, such as the HIF-1α and estrogen-related receptor α (ERRα). However, the expression of ERRα is unchanged by KRGE in astrocytes of the mouse brain cortex. Instead, sirtuin 3 (SIRT3) expression is induced by KRGE in astrocytes. SIRT3 is a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase that resides in the mitochondria and maintains mitochondrial homeostasis. Mitochondrial maintenance requires oxygen, and active mitochondria enhance oxygen consumption, resulting in hypoxia. The effects of SIRT3 on HIF-1α-mediated mitochondria functions induced by KRGE are not well established. We aimed to investigate the relationship between SIRT3 and HIF-1α in KRGE-treated normoxic astrocyte cells. Without changing the expression of the ERRα, small interfering ribonucleic acid targeted for SIRT3 in astrocytes substantially lowers the amount of KRGE-induced HIF-1α proteins. Reduced proline hydroxylase 2 (PHD2) expression restores HIF-1α protein levels in SIRT3-depleted astrocytes in normoxic cells treated with KRGE. The translocation of outer mitochondrial membranes 22 (Tom22) and Tom20 is controlled by the SIRT3-HIF-1α axis, which is activated by KRGE. KRGE-induced Tom22 increased oxygen consumption and mitochondrial membrane potential, as well as HIF-1α stability through PHD2. Taken together, in normoxic astrocytes, KRGE-induced SIRT3 activated the Tom22-HIF-1α circuit by increasing oxygen consumption in an ERRα-independent manner.

Abstract 3070: Leveraging oxysterol sulfation by SULT2B1b sulfotransferase and liver X receptor inactivation to suppress advanced prostate cancer

Abstract Advanced prostate cancer is a heterogeneous disease driven by diverse genetic alterations, with metastasis and lethal progression as the inevitable outcome. We observed that a subset of clinical primary prostate cancer is markedly reduced for SULT2B1b (SULT2B) sulfotransferase, which is an oxysterol-sulfating enzyme. Metastasized castration-resistant prostate cancer (CRPC) uniformly lacks SULT2B. Oxysterols are oxidized cholesterol metabolites and in agonist function, they activate liver X receptors (LXRα/β), which are members of the nuclear receptor family and regulators of lipogenesis, cholesterol homeostasis and immune functions. LXR signaling is enzymatically inhibited by SULT2B activity since sulfated oxysterols are LXR-inert. We previously reported that genetic silencing of SULT2B led to escalated CRPC proliferation; enhanced xenograft tumor growth; increased cell migration, invasion; reduced stiffness, adhesiveness; and EMT activation. SULT2B-depleted CRPC cells showed robust upregulation of AKR1C3 aldo-keto reductase and AKR1C3-dependent activation of the ERK1/2 survival signal. AKR1C3 regulates intratumoral androgen biosynthesis, and it is known to be elevated in advanced prostate cancer. In the current study, we validate our previous result by showing that ectopic expression of SULT2B caused AKR1C3 reduction in CRPC cells. Mechanistically, we observed that enhanced AKR1C3 expression in SULT2B-depleted cells was prevented upon genetic or pharmacologic inactivation of LXR. In addition, ERRα, another non-steroid nuclear receptor, was reduced in LXR-inactivated cells and notably, AKR1C3 was reduced in CRPC cells upon ERRα degradation by an ERRα-selective PROTAC. The LXR dependence of ERRα and AKR1C3 expression was observed in both androgen receptor expressing and non-expressing CRPC cells. Conclusion & Translational Significance: Above results reveal a novel LXR-ERRα-AKR1C3-ERK axis which is activated in SULT2B-deficient CRPC cells irrespective of the androgen receptor status of these cells. Notably, elevated ERRα portends poor prognosis for prostate cancer and cholesterol is an ERRα agonist. Considering that statin can diminish ERRα activity (PMID 26777690) and AKR1C3 inhibitors are in clinical trials, this novel axis revealed from our study may be actionable for the clinical interception of the progression in SULT2B-low advanced prostate cancer. Citation Format: Bobae Park, Katarzyna Knapczyk-Stwora, Yaguang Liu, Chung S. Song, Bandana Chatterjee. Leveraging oxysterol sulfation by SULT2B1b sulfotransferase and liver X receptor inactivation to suppress advanced prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3070.

Adrenocortical Carcinoma (ACC) Cells Rewire Their Metabolism to Overcome Curcumin Antitumoral Effects Opening a Window of Opportunity to Improve Treatment

Extensive research suggests that curcumin interferes with multiple cell signaling pathways involved in cancer development and progression. This study aimed to evaluate curcumin effects on adrenocortical carcinoma (ACC), a rare but very aggressive tumor. Curcumin reduced growth, migration and activated apoptosis in three different ACC cell lines, H295R, SW13, MUC-1. This event was related to a decrease in estrogen-related receptor-α (ERRα) expression and cholesterol synthesis. More importantly, curcumin changed ACC cell metabolism, increasing glycolytic gene expression. However, pyruvate from glycolysis was only minimally used for lactate production and the Krebs cycle (TCA). In fact, lactate dehydrogenase, extracellular acidification rate (ECAR), TCA genes and oxygen consumption rate (OCR) were reduced. We instead found an increase in Glutamic-Pyruvic Transaminase (GPT), glutamine antiport transporter SLC1A5 and glutaminase (GLS1), supporting a metabolic rewiring toward glutamine metabolism. Targeting this mechanism, curcumin effects were improved. In fact, in a low glutamine-containing medium, the growth inhibitory effects elicited by curcumin were observed at a concentration ineffective in default growth medium. Data from this study prove the efficacy of curcumin against ACC growth and progression and point to the concomitant use of inhibitors for glutamine metabolism to improve its effects.

Beneficial Mitochondrial Biogenesis in Gastrocnemius Muscle Promoted by High-Intensity Interval Training in Elderly Female Rats.

Exercise can attenuate mitochondrial dysfunction caused by aging. Our study aimed to compare 12 weeks of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on the expression of mitochondria proteins [e.g., AMP-activated protein kinase (AMPK), Estrogen-related receptor alpha (ERRα), p38 mitogen-activated protein kinase (P38MAPK), and Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1-α)] in gastrocnemius muscle of old female rats. In this experimental study, thirty six old female Wistar rats (18-month-old and 270-310 g) were divided into three groups: i. HIIT, ii. MICT, and iii. Control group (C). The HIIT protocol was performed for 12 weeks with 16-28 minutes (2 minutes training with 85-90% VO2max in high intensity and 2 minutes training with 45-75% VO2max low intensity). The MICT was performed for 30-60 minutes with the intensity of 65-70% VO2max. The gastrocnemius muscle expression of AMPK, ERRα, P38MAPK, and PGC1α proteins were determined by Western blotting. The expression of AMPK (P=0.004), P38MAPK (P=0.003), PGC-1α (P=0.028), and ERRα (P=0.006) in HIIT was higher than C group. AMPK (P=0.03), P38MAPK (P=0.032), PGC-1α (P=0.015), and ERRα (P=0.028) in MICT was higher than the C group. Also expression of AMPK (P=0.008), P38MAPK (P=0.009), PGC-1α (P=0.020) and ERRα (P=0.014) in MICT was higher than MICT group. It seems that exercise training has beneficial effects on mitochondrial biogenesis, but the HIIT training method is more effective than MICT in improving mitochondrial function in aging.

Ginsenoside Rd, a natural production for attenuating fibrogenesis and inflammation in hepatic fibrosis by regulating the ERRα-mediated P2X7r pathway.

Ginseng, when used as a food and nutritional supplement, has the ability to regulate human immunity. Here, the potential anti-hepatic fibrosis effect of ginsenoside Rd (Rd), one of the protopanaxadiol types of ginsenoside, was investigated. We established a hepatic fibrosis model using intraperitoneal injection of thioacetamide (TAA) for five weeks in mice. In addition, an in vitro model was established by using TGF-β to activate hepatic stellate cells (HSCs), treated with Rd and an estrogen-related receptor α (ERRα) inhibitor (XCT-790). The ERRα knockdown (shRNA-ERRα) of the primary mouse hepatocytes was used to establish hepatocyte injury by TGF-β, and they were then incubated in Rd. The Rd significantly alleviated the histopathological changes, and reduced the serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. The Rd could upregulate the ERRα and downregulate the fibrosis markers in the livers of mice. In TAA-induced mice, the Rd inhibited the purinergic ligand-gated ion channel 7 receptor (P2X7r)-mediated NLRP3 inflammasome activation, consequently reversing the liver inflammatory response. The Rd significantly increased the expression of ERRα and suppressed the extracellular matrix (ECM) in the HSCs or primary hepatocytes. The Rd significantly decreased the P2X7r-mediated NLRP3 inflammasome activation, consequently reversing the inflammatory response, including the production of IL-1β, IL-23 in the activated HSCs and primary hepatocytes. The Rd could ameliorate the damage of the hepatocytes and further inhibit the entry of IL-1β and IL-18 into the extracellular matrix. The Rd reduced the inflammatory reaction by regulating the ERRα-P2X7r signaling pathway while suppressing the fibrogenesis, which suggests that the Rd can serve as a novel dietary supplement approach to combat hepatic fibrosis.

ERRα attenuates vascular inflammation via enhanced NFκB degradation pathway.

We have previously reported that β-aminoisobutyric acid (BAIBA), a muscle-derived exercise mimetic, had anti-inflammatory and reactive oxygen species (ROS) scavenging effects in vascular endothelial cells through the enhanced expression of peroxisome proliferator-activated receptor gamma coactivator-1β (PGC-1β). Although BAIBA also increased the expression of estrogen-related receptor α (ERRα), the roles of ERRα in vascular endothelial cells have yet to be fully elucidated. Here, we found that human aortic endothelial cells (HAEC)-infected with ERRα-expressing adenovirus had significantly decreased mRNA levels of TNFα-stimulated pro-inflammatory molecules. However, ERRα overexpression had little effects on the mRNA levels of PGC-1β, peroxisome proliferator-activated receptors (PPAR), and almost all ROS scavenging molecules, except for superoxide dismutase 2 (SOD2). ERRα expression significantly decreased NFκB reporter activities in a dose-dependent manner with unaltered IκBα phosphorylation levels but with a significant increase in the mRNA levels of PDZ and LIM domain protein 2 (PDLIM2) and copper metabolism gene MURR1 domain-containing protein (COMMD1), which enhance the ubiquitination and degradation of NFκB. Also, PDLIM2 and COMMD1 mRNA levels were upregulated in BAIBA-treated HAEC. Finally, we identified the ERRα-response element in the COMMD1 promoter region (-283 to -29 bp). These results indicated that ERRα exerted anti-inflammatory effects in vascular endothelial cells through COMMD1-mediated attenuation of NFκB activity, which could be one of the atheroprotective mechanisms of physical exercise.

Regulation of SIRT1-TLR2/TLR4 pathway in cell communication from macrophages to hepatic stellate cells contribute to alleviates hepatic fibrosis by Luteoloside

Regulating macrophage-hepatic stellate cells (HSCs) crosstalk through SIRT1-TLR2/TLR4 has contributed to the essence of new pharmacologic strategies to improve hepatic fibrosis. We investigated how Luteoloside (LUT), one of the flavonoid monomers isolated from Eclipta prostrata (L.) L., modulates macrophage-HSCs crosstalk during hepatic fibrosis. HSC-T6 or rat peritoneal macrophages were activated by TGF-β or LPS/ATP, and then treated with LUT or Sirtinol (SIRT1 inhibitor) for 6 h. Further, HSCs were cultured with the conditioned medium from the LPS/ATP activated peritoneal macrophages. In HSC-T6 or peritoneal macrophages, LUT could decrease the expressions of α-SMA, Collagen-I, the ratio of TIMP-1/MMP-13. LUT also significantly increased the expressions of SIRT1 and ERRα. And LUT significantly suppressed the releases of pro-inflammatory cytokines, including NLRP3, ASC, caspase-1, IL-1β, and regulated signaling TLR2/TLR4-MyD88 activation. The expressions of TLR2, TLR4, NLRP3, caspase-1, IL-1β, α-SMA were increased and the expression of ERRα was decreased by Sirtinol, indicated that LUT might mediate SIRT1 to regulate TLR4 expression and further alleviate inflammation and fibrosis. LUT could regulate SIRT1-mediated TLR4 and ECM in HSCs was reduced, when HSCs were cultured with conditioned medium. Hence, LUT could decrease the expressions of fibrosis markers, reduce the releases of inflammatory cytokines in activated HSCs or macrophages. In conclusion, LUT might be a promising candidate that regulating SIRT1-TLR2/TLR4 signaling in macrophages interacting with HSCs during hepatic fibrosis.

Association of Irisin/FNDC5 with ERRα and PGC-1α Expression in NSCLC.

The rapid growth and division of cancer cells are associated with mitochondrial biogenesis or switching to glycolysis. ERRα, PGC-1α and irisin/FNDC5 are some of the proteins that can influence these processes. The aim of this study was to determine the correlation of these proteins in non-small cell lung cancer (NSCLC) and to investigate their association with clinicopathological parameters. Immunohistochemistry reactions were performed on tissue microarrays (860 NSCLC, 140 non-malignant lung tissue). The normal fibroblast cell line (IMR-90) and lung cancer cell lines (NCI-H1703 and NCI-H522) were used as co-cultures. The mRNA levels of FNDC5 and ESRRA (encoding ERRα) were assessed in IMR-90 cells after co-culture with lung cancer cells. We observed a decreased level of ERRα with an increase in tumor size (T), stages of the disease, and lymph node metastases (N). In the adenocarcinoma (AC) subtype, patients with a higher ERRα expression had significantly longer overall survival. A moderate positive correlation was observed between FNDC5 mRNA and ESRRA mRNA in NSCLCs. The expression of FNDC5 mRNA in IMR-90 cells increased after 24 h, and ESRRA gene expression increased after 48 h of co-culture. The ERRα receptor with PGC-1α participates in the control of FNDC5/irisin expression. Normal fibroblasts revealed an upregulation of the FNDC5 and ESRRA genes under the influence of lung cancer cells.

Efficacy of glucose transporter inhibitors for the treatment of ERRα-overexpressed colorectal cancer.

Colorectal cancer is the most-incidence associated extremely high mortality rate worldwide. The overexpression of estrogen-related receptor α (ERRα) is contributing to a poor prognosis. Obtaining a better understanding of the mechanisms of ERRα in colorectal cancer is important for developing cancer therapies. Western blotting and qRT-PCR were used to determine the protein and mRNA levels of ERRα, OUTB1, and solute carrier family 7 member 11 (SLC7A11) in HCT-116 cells. Short hairpin RNA (shRNA) was used to knockdown ERRα in HCT-116 cells. The level of reactive oxygen species (ROS), the nicotinamide adenine dinucleotide phosphate NADP+/NADPH, and the oxidized glutathione (GSSG)/reduced glutathione (GSH) ratio were measured by HPLC-MS to determine the redox state in HCT-116 cells. Lastly, tumor xenograft experiments were carried out to determine the effect of glucose transporter (GLUT) inhibitor. Knockdown of ERRα decreased the expression of OTUB1 and SLC7A11 in HCT-116 cells. SLC7A11 overexpression induced NADPH-dependent redox system collapse. Aberrant expression of ERRα significantly reduced NADPH level and resulted in collapse of the redox system under glucose deprivation. Furthermore, ERR overexpression of ERRα sensitized cancer cells to inhibition of GLUTs. Treatment with GLUT inhibitor significantly reduced tumor volume after 6 weeks of tumor xenograft experiment. Our study demonstrates that the over-expression of ERRα causes redox system collapses via regulating the expressions of OUTB1 and SLC7A11. Up-regulation of SLC7A11 mediates the disruption of cell metabolism and the balance of redox state in colorectal cancer. Additionally, the GLUT inhibitor significantly reduces colorectal tumor volume, suggesting that the GLUT inhibitor could serve as a potential therapy for colorectal treatment.

IGF2BP1-regulated expression of ERRα is involved in metabolic reprogramming of chemotherapy resistant osteosarcoma cells

Doxorubicin (Dox) is the standard treatment approach for osteosarcoma (OS), while acquired drug resistance seriously attenuates its treatment efficiency. The present study aimed to investigate the potential roles of metabolic reprogramming and the related regulatory mechanism in Dox-resistant OS cells. The results showed that the ATP levels, lactate generation, glucose consumption and oxygen consumption rate were significantly increased in Dox-resistant OS cells compared with parental cells. Furthermore, the results revealed that the increased expression of estrogen-related receptor alpha (ERRα) was involved in metabolic reprogramming in chemotherapy resistant OS cells, since targeted inhibition of ERRα restored the shifting of metabolic profiles. Mechanistic analysis indicated that the mRNA stability, rather than ERRα transcription was markedly increased in chemoresistant OS cells. Therefore, it was hypothesized that the 3ʹ-untranslated region of ERRα mRNA was methylated by N6-methyladenine, which could further recruit insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) to suppress mRNA decay and increase mRNA stability. IGF2BP1 knockdown downregulated ERRα and reversed the metabolic alteration of resistant OS cells. Additionally, the oncogenic effect of the IGF2BP1/ERRα axis on Dox-resistant OS cells was verified by in vitro and in vivo experiments. Clinical analysis also revealed that the expression levels of IGF2BP1 and ERRα were associated with the clinical progression of OS. Collectively, the current study suggested that the IGF2BP1/ERRα axis could regulate metabolic reprogramming to contribute to the chemoresistance of OS cells.

Intervention of ERRα Expression on Apoptosis Induction of Multiple Myeloma MM.1S Cells Cultured in Vitro

To investigate the effect of two different approaches ERRα strategy on the apoptosis in multiple myeloma cell line MM.1S. For the one strategy, shRNA was mediated by lentivirus. Stable cell clones were established by transfecting the lentivirus into MM.1S cells and screened by puromycin. For the other strategy, XCT790, a specific reverse agonist of ERRα, was used to treat MM.1S cells. The apoptosis of the cells was analyzed by flow cytometry after ERRα was down-regulated. Western blot assay was used to detect the apoptosis of related proteins. The knocked down ERRα was achieved, lentivirus with shERRα were successfully infected into MM.1S and ERRα was reduced significantly. Knockdown of ERRα could induce MM.1S cell apoptosis dramatically. Meanwhile, the expression of cleaved PARP (a kind of apoptosis related markers) was significantly increased following depletion of ERRα in MM.1S cells. XCT790 could significantly down-regulate the expression of ERRα protein in MM.1S cells, which was consistent with the effect caused by shRNA. Interference the expression of ERRα by shRNA or XCT790 can induce apparent apoptosis in MM.1S cells, which indicating that ERRα is crucial for the survival of myeloma cells.

Cholesterol promotes EGFR-TKIs resistance in NSCLC by inducing EGFR/Src/Erk/SP1 signaling-mediated ERR\u03b1 re-expression

BackgroundThe use of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) brings remarkable benefits for the survival of patients with advanced NSCLC harboring EGFR mutations. Unfortunately, acquired resistance seems to be inevitable and limits the application of EGFR-TKIs in clinical practice. This study reported a common molecular mechanism sustaining resistance and potential treatment options to overcome EGFR-TKIs resistance.MethodsEGFR-TKIs resistant NSCLC cells were established and confirmed by MTT assay. Cholesterol content was detected and the promotional function of cholesterol on NSCLC growth was determined in vivo. Then, we identified ERRα expression as the downstream factor of cholesterol-mediated drug resistance. To dissect the regulatory mechanism, we conducted experiments, including immunofluorescence, co-immunoprecipitation, luciferase reporter assay and chromatin immunoprecipitation assay.ResultsLong-term exposure to EGFR-TKIs generate drug resistance with the characteristic of cholesterol accumulation in lipid rafts, which promotes EGFR and Src to interact and lead EGFR/Src/Erk signaling reactivation-mediated SP1 nuclear translocation and ERRα re-expression. Further investigation identifies ERRα as a target gene of SP1. Functionally, re-expression of ERRα sustains cell proliferation by regulating ROS detoxification process. Lovastatin, a drug used to decrease cholesterol level, and XCT790, an inverse agonist of ERRα, overcome gefitinib and osimertinib resistance both in vitro and in vivo.ConclusionsOur study indicates that cholesterol/EGFR/Src/Erk/SP1 axis-induced ERRα re-expression promotes survival of gefitinib and osimertinib-resistant cancer cells. Besides, we demonstrate the potential of lowing cholesterol and downregulation of ERRα as effective adjuvant treatment of NSCLC.

Zearalenone promotes follicle development through activating the SIRT1/PGC-1α signaling pathway in the ovaries of weaned gilts.

This study aimed to investigate the effect of zearalenone (ZEA) exposure on follicular development in weaned gilts, and its mechanism based on the silent information regulator 1 (SIRT1)/peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α) signaling pathway. A total of 32 healthy female weaned piglets (Landrace × Yorkshire × Duroc) with an average body weight of 12.39±0.24kg were randomly allotted to a basal diet supplemented with 0, 0.15, 1.5, or 3.0mg/kg ZEA for a 32-d feeding test. Blood and ovarian samples were obtained at the end of the experiment to determine serum toxin concentrations, ovarian histology, and the expressions of proliferating cell nuclear antigen (PCNA) and SIRT1/PGC-1α signaling pathway-related genes. Results showed that the vulva area, serum concentrations of ZEA, α-zearalenol and β-zearalenol, the thickness of the growing follicular layer, and the diameter of the largest growing follicles, as well as the expressions of SIRT1, PGC-1α, estrogen-related receptor α (ERRα), ATP synthase subunit beta (ATP5B), and PCNA, increased linearly (P < 0.05) with increasing dietary ZEA, whereas the thickness of the primordial follicle layer decreased linearly (P < 0.05). Immunohistochemical analysis showed that the immunoreactive substances of SIRT1 and PGC-1α in the ovaries enhanced with the increasing dietary ZEA (P < 0.05). In addition, the thickness of the growing follicular layer and the diameter of the largest growing follicle were positively correlated with relative mRNA and protein expressions of SIRT1, PGC-1α, ERRα, ATP5B, and PCNA (P < 0.05). However, the thickness of the primordial follicle layer was negatively correlated with the mRNA and protein expression of SIRT1, PGC-1α, ERRα, ATP5B, and PCNA (P < 0.05). Interestingly, the 1.5mg/kg ZEA treatment had highly hyperplastic follicles, whereas 3.0mg/kg ZEA resulted in a large number of follicular atresia, which indicated that low-dose ZEA exposure accelerated follicular proliferation, while high-dose ZEA promoted follicular atresia, although the critical value interval needs further confirmation. Results provide a theoretical basis for finding the therapeutic target of ZEA-induced reproductive disorders in weaned gilts.