ERRα Expression Research Articles

The Increased Expression of Estrogen-Related Receptor α Correlates with Wnt5a and Poor Prognosis in Patients with Glioma.

Malignant glioma is an often fatal type of cancer. Elevated expression of the orphan nuclear receptor estrogen-related receptor alpha (ERRα) is an unfavorable factor for malignant progression and poor prognosis in several cancers, although the mechanism by which this receptor affects the pathophysiology of cancers remains obscure. However, few studies have been conducted in regard to the role of ERRα in glioma. In the current study, we found that elevated expression of ERRα was observed in 107 glioma cases by means of IHC. Clinically, high expression of ERRα was associated with later stages of disease progression and clinical outcome of patients with glioma. ERRα had the ability to promote cell proliferation and migration in glioma cell lines. Moreover, in a xenograft model, we also found that silencing ERRα had an inhibitory effect on the growth of glioma. Further investigation confirmed that ERRα was involved in the carcinogenesis of glioma via the regulation of the Wnt5a signal pathway in vitro and in vivo Our study was first to show the overexpression of ERRα in glioma tissues and a direct correlation between ERRα expression and clinical prognosis of glioma. Together, these data reveal that ERRα has prognostic significance in glioma, and targeting ERRα may provide a reliable therapeutic strategy for the treatment for human glioma.

ERRα promotes breast cancer cell dissemination to bone by increasing RANK expression in primary breast tumors.

Bone is the most common metastatic site for breast cancer. Estrogen-related-receptor alpha (ERRα) has been implicated in cancer cell invasiveness. Here, we established that ERRα promotes spontaneous metastatic dissemination of breast cancer cells from primary mammary tumors to the skeleton. We carried out cohort studies, pharmacological inhibition, gain-of-function analyses in vivo and cellular and molecular studies in vitro to identify new biomarkers in breast cancer metastases. Meta-analysis of human primary breast tumors revealed that high ERRα expression levels were associated with bone but not lung metastases. ERRα expression was also detected in circulating tumor cells from metastatic breast cancer patients. ERRα overexpression in murine 4T1 breast cancer cells promoted spontaneous bone micro-metastases formation when tumor cells were inoculated orthotopically, whereas lung metastases occurred irrespective of ERRα expression level. In vivo, Rank was identified as a target for ERRα. That was confirmed in vitro in Rankl stimulated tumor cell invasion, in mTOR/pS6K phosphorylation, by transactivation assay, ChIP and bioinformatics analyses. Moreover, pharmacological inhibition of ERRα reduced primary tumor growth, bone micro-metastases formation and Rank expression in vitro and in vivo. Transcriptomic studies and meta-analysis confirmed a positive association between metastases and ERRα/RANK in breast cancer patients and also revealed a positive correlation between ERRα and BRCA1mut carriers. Taken together, our results reveal a novel ERRα/RANK axis by which ERRα in primary breast cancer promotes early dissemination of cancer cells to bone. These findings suggest that ERRα may be a useful therapeutic target to prevent bone metastases.

Heme oxygenase metabolites improve astrocytic mitochondrial function via a Ca2+-dependent HIF-1α/ERRα circuit

Heme oxygenase-1 (HO-1) exerts beneficial effects, including angiogenesis and energy metabolism via the hypoxia-inducible factor-1α (HIF-1α) and peroxisome-proliferator-activating receptor-γ coactivator-1α (PGC-1α)/estrogen-related receptor α (ERRα) pathways, respectively, in astrocytes. However, evidence of cross-talk between both pathways in HO metabolite-mediated mitochondrial biogenesis has not been well elucidated. Here, we found that HIF-1α was upregulated in astrocytes after ischemic brain injury following exposure to the carbon monoxide (CO)-releasing compound CORM-2. Experiments with pharmacological inhibitors and target-specific siRNAs revealed that HIF-1α levels were highly correlated with increased PGC-1α and ERRα levels, which were linked to the HO metabolites CO- and bilirubin-induced activation of apical L-type Ca2+ channel and sequential Ca2+-dependent signal transduction. Moreover, HIF-1α was stabilized in a proline hydroxylase-dependent manner by transient induction of intracellular hypoxia via the PGC-1α/ERRα-induced increases in mitochondrial biogenesis and oxygen consumption. HIF-1α knockdown blocked HO-1 system-mediated transcriptional expression of ERRα, but not of PGC-1α, suggesting a possible involvement of HIF-1α in ERRα-mediated mitochondrial biogenesis. These data suggest that the HO-1-derived metabolites, CO and bilirubin, elevate astrocytic mitochondrial function via a HIF-1α/ERRα circuit coupled with L-type Ca2+ channel activation and PGC-1α-mediated oxygen consumption. This circuit may play an important role in repairing neurovascular function after focal ischemic brain injury by stimulating mitochondrial biogenesis.

Bisphenol S Triggers the Migration and Invasion of Pheochromocytoma PC12 Cells via Estrogen-Related Receptor α.

Pheochromocytoma (PCC) is a tumor of the adrenal medulla for which surgical resection is the only therapy approach. Risk factors responsible for the tumorigenesis and progression of PCC are not well illustrated. Our present study revealed that an industrial chemical, bisphenol S (BPS), can promote the migration and invasion of PCC PC12 cells, which was evidenced by the upregulation of fibronectin (FN) and matrix metalloproteinases (MMP-2 and MMP-9). The inhibitor of estrogen-related receptor α (ERRα), while not estrogen receptor α/β (ERα/β) or G protein-coupled estrogen receptor (GPER), can attenuate BPS-induced cell migration. Mechanically, BPS can increase the binding between ERRα and promoter of FN1 and then induce the expression of FN in PC12 cells. Further, BPS can induce the expression of miR-10b in PC12 cells via ERRα. The upregulated miR-10b inhibited the expression of KLF4, which can suppress the migration and invasion of cancer cells. BPS can trigger the mRNA and protein expression of ERRα in PC12 cells via a time-dependent manner. Collectively, our study revealed that nanomolar BPS can trigger the migration and invasion of PC12 cells via activation and upregulation of ERRα.

Novel endocrine therapeutic strategy in endometrial carcinoma targeting estrogen-related receptor α by XCT790 and siRNA.

PurposeTo explore the targeted therapy of estrogen-related receptor α (ERRα) in endometrial cancer (EC) cells and its potential mechanisms.MethodsThe mRNA and protein expression levels of ERRα and estrogen receptor α (ERα) were detected by qPCR and Western blotting in RL-952, AN3-CA, HEC-1A, and HEC-1B EC cell lines. After treatment with the ERRα-specific antagonist XCT790 or infection with lentivirus-mediated small interfering RNA (siRNA) targeting the ERRα (siRNA-ERRα), cell proliferation and apoptosis were evaluated by MTS assay and flow cytometry. After treatment with siRNA-ERRα, the expression profiles of transcription factors (TFs) were analyzed by protein/DNA arrays in EC cells.ResultsThe relative mRNA levels of ERRa in RL-952 (1±0.0831) and AN3-CA (1.162±0.0325) were significantly higher than those in HEC-1A (0.3081±0.0339) and HEC-1B (0.1119±0.0091) (P<0.05), and similar results were observed for ERRα protein levels. A higher ratio of ERa/ERRa was observed in ERα-positive RL-952 (10-fold) and ANC-3A (8.5-fold) cells, whereas a lower ratio was observed in ERα-negative HEC-1A (3.75-fold) and HEC-1B cells (0-fold). Both – exogenous XCT790 and endogenous siRNA-ERRα – can decrease the expression of ERRα, thereby inhibiting proliferation but promoting apoptosis in both ERα-positive and -negative EC cells. The XCT790 presented higher proliferation-inhibition and apoptosis rates in the ERα-positive than ERα-negative cells, whereas the siRNA-ERRα exhibited higher proliferation-inhibition and apoptosis rates in the ERα-negative than in ERα-positive cells. In total, 3 upregulated and 17 downregulated TFs were screened out by knocked-down expression of ERRα in all EC cells. Among them, the upregulated TFs organic cation transporter 3/4(Oct3/4), hepatic nuclear factor 4 (HNF4), HNF4 and chicken ovalbumin upstream TF (COUP-TF) as well as downregulated transcription factor EB (TFEB) were found to be statistically significant (P<0.05).ConclusionTargeting ERRα provides a promising novel endocrine therapeutic strategy.

Abstract 5495: Inhibiting ERRα blocks liver steatosis and tumorigenesis induced by PTEN loss

Abstract Mitochondrial dysfunction has been attributed to be a major cause for fatty liver development and also underlies tumor development. Using a liver-conditional Pten deletion model where the activation of its downstream PI3K/AKT signaling led to fatty liver, steatohepatitis, fibrosis and finally liver cancer development, we reported previously that the fatty liver and liver cancer is accompanied by elevated mitochondrial bioenergetics and a dramatic induction of estrogen-related receptor α (ERRα), a master regulator that orchestrate mitochondria response to modulate metabolism. In this project, we intended to investigate whether blocking ERRα expression and inhibiting mitochondrial respiration can attenuate tumor growth and lipid accumulation in the Pten null livers and human liver cancer cells. Using a genetic knockdown approach with siERRα and chemical genomic approach with a small molecular polyamide compound that binds to the ERRα consensus binding site, we showed that ERRα knockdown suppressed mitochondrial function and impeded cell proliferation in human liver as well as prostate cancer cell lines lacking Pten. In addition, blocking ERRα transcriptional activity with ERRα specific polyamide err-PA significantly reduced tumor growth in xenograft models. Furthermore, err-PA administration in vivo in 1.5-month old liver- specific Pten null mice remarkably prevented the development of fatty liver morphology and quantitatively reduced the hepatic triglyceride level. In summary, our study highlights ERRα's crucial role in regulating mitochondrial bioenergetics and underscores its therapeutic potential in cancer and lipid disorders. Citation Format: Chien-Yu Chen, Yang Li, Jingyu Chen, Lina He, Bangyan Stiles. Inhibiting ERRα blocks liver steatosis and tumorigenesis induced by PTEN loss [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5495.

Estrogen-related receptor alpha triggers the proliferation and migration of human non-small cell lung cancer via interleukin-6.

Human non-small cell lung cancer (NSCLC) is one of the leading causes of cancer deaths worldwide. Estrogenic signals have been suggested to be important for the growth and metastasis of NSCLC cells. Our present data showed that estrogen-related receptor alpha (ERRα), while not ERRβ or ERRγ, was significantly elevated in NSCLC cell lines as compared with that in normal bronchial epithelial cell line BEAS-2B. The expression of ERRα in clinical NSCLC tissues was significantly greater than that in their matched normal adjacent tissues. Over expression of ERRα can trigger the proliferation, migration, and invasion of NSCLC cells, while si-ERRα or ERRα inhibitor showed opposite effects. ERRα can increase the mRNA and protein expression of IL-6, while not IL-8, IL-10, IL-22, VEGF, TGF-β, or TNF-α, in NSCLC cells. Silence of IL-6 attenuated ERRα induced proliferation and cell invasion. Furthermore, our data revealed the inhibition of NF-κB, while not ERK1/2 or PI3K/Akt, abolished ERRα induced production of IL-6. This might be due to that overexpression of ERRα can increase the expression and nuclear translocation of p65 in NSCLC cells. Collectively, our data showed that activation of NF-κB/IL-6 is involved in ERRα induced migration and invasion of NSCLC cells. It suggested that ERRα might be a potential target for NSCLC treatment.

Estrogen-related receptor α is essential for maintaining mitochondrial integrity in cisplatin-induced acute kidney injury

Acute kidney injury (AKI) has been associated with not only higher in-hospital mortality but also the subsequent development of chronic kidney disease (CKD). Recent evidence has suggested the involvement of mitochondrial dysfunction and impaired dynamics in the pathogenesis of AKI. Estrogen-related receptor α (ERRα) is an orphan nuclear receptor that acts as a transcription factor to regulate the transcription of genes required for mitochondrial biogenesis and oxidative phosphorylation. In the present study, we examined the effects of ERRα deficiency on the progression of AKI induced by cisplatin. Male C57BL/6 J wild-type and ERRα−/- mice received a single intraperitoneal injection of 20 mg/kg cisplatin. Seventy-two hours after the injection, kidney function and morphology were evaluated. ERRα expression was observed in renal tubules, and cisplatin inhibited its translocation into nuclei. ERRα deficiency exacerbated cisplatin-induced renal dysfunction and tubular injury, as well as oxidative stress and apoptosis. ERRα−/- mice kidneys revealed lower mitochondrial DNA content and swollen mitochondria with reduced cristae. In addition, these mice had lower expression of the mitochondrial fusion protein mitofusin-2. The cisplatin-induced decrease in mitochondrial DNA and altered mitochondrial structure were more severe in ERRα−/- mice. In cultured mouse proximal tubular epithelial cells, the ERRα inverse agonist XCT-790 significantly inhibited mitofusin-2 expression and induced mitochondrial fragmentation. Taken together, our findings suggest the involvement of ERRα in the progression of cisplatin-induced AKI probably through impaired mitochondrial dynamics.

Downregulation of estrogen-related receptor alpha inhibits human cutaneous squamous cell carcinoma cell proliferation and migration by regulating EMT via fibronectin and STAT3 signaling pathways

Estrogen-related receptor alpha (ERRα), one of orphan nuclear receptors, has been recently revealed as an oncogenic regulator in a variety of cancers. However, the linking gain of ERRα expression and cancer progression in cutaneous squamous cell carcinoma (cSCC) is largely unknown. Here, we showed that the mRNA and protein expression levels of ERRα were markedly higher in A431 cells compared with human keratinocyte cell line HaCaT, and targeted inhibition of ERRα by shRNA or its inverse agonist XCT790 significantly suppressed A431 cells proliferation and migration, while overexpression of ERRα promoted cell proliferation and migration. In addition, the data revealed that ERRα downregulation markedly inhibited the epithelial mesenchymal transition (EMT) of A431 cells with increasing the expression of E-cadherin and decreasing fibronectin (FN) and vimentin. Results from further experiments using Western blot suggested that ERRα suppression inhibited signal transducer and activator of transcription (STAT3) protein expression. In contrast, overexpression of ERRα promoted EMT and the activation of STAT3 pathway. Moreover, treatment with specific STAT3 inhibitor reversed EMT markers in ERRα-overexpressing A431 cells. In tumor xenografts of A431 cells, we further showed that ERRα depletion inhibited cSCC tumor growth in vivo. Taken together, these results demonstrate, for the first time, that ERRα may function as an oncoprotein in cSCC to accelerate tumor aggressiveness by promoting EMT via FN and STAT3 pathway, and it could be a novel target for cSCC therapy.

High expression of estrogen-related receptor α is significantly associated with poor prognosis in patients with colorectal cancer.

Colorectal cancer (CRC) is one of the most common types of malignancy with high morbidity and mortality rates worldwide. This biologically heterogeneous disease results in diverse therapeutic responses, thus, novel prognostic biomarkers are required to improve CRC treatment. Estrogen-related receptor α (ERRα) is a nuclear orphan receptor, which is associated with estrogen receptor α. The present study aimed to investigate the expression of ERRα in patients with CRC, and explore the association between ERRα expression and clinicopathological factors, local recurrence and prognosis. In the present study, ERRα expression was detected in 15 fresh CRC tissues using quantitative real-time polymerase chain reaction (RT-qPCR) and in 128 paraffin-embedded CRC tissues using immunohistochemistry. The associations between ERRα expression and prognosis of CRC patients were evaluated by univariate, and multivariate (Cox proportional hazards model) analysis. RT-qPCR demonstrated that the mRNA expression of ERRα in CRC tissues was significantly higher compared with that in matched normal tissues. Immunohistochemistry revealed that ERRα high expression was detected in the nuclei of cancer cells from 39.1% (50/128) of CRC tissues. ERRα expression based on immunohistochemical staining was significantly associated with tumor differentiation, tumor invasion, lymph node status and Dukes stage (all P<0.05). Furthermore, patients with high ERRα expression were significantly associated with an increased risk of recurrence and poor prognosis, compared with patients with low ERRα expression. ERRα expression was identified as an independent prognostic factor for patients with CRC. In conclusion, ERRα serves important roles in the progression of CRC and is a potential prognostic factor for patients with CRC.

Expression and change of ERRα inoxaliplatin-resistant colon cancer cells after the downregulation of tetrasoanin

Objective To observe the proliferation and apoptosis of oxaliplatin-resistant colon cancer cell lines and the expression of estrogen receptor related receptor (ERR)α when tetrasoanin was down-regulated. Methods Western blot and quantitative real-time polymerase chain reaction(qRT-PCR) were used to detect the expression of tetrasoanin and ERRα of colon cancer cells and oxaliplatin resistant cells in mRNA and protein levels. ERRα inhibitor XCT790 was used to down-regulate ERRα expression, The expression of ERRα was down regulated by ERR α inhibitor XCT790, and the level of tetrasoanin, apoptosis and proliferation of L-OHP-SW620 cells were detected by Western blot, flow cytometry and MTT.Tetrasoanin expression was down regulated by siRNA, the expression, apoptosis and proliferation of L-OHP-SW620 cells AKT, p-AKT, tetrasoanin and ERRα were detected by Western blot, qRT-PCR, flow cytometry and MTT assay. Results The expression of tetrasoanin and ERRα protein in L-OHP-SW620 cell lines were higher than those in SW620 cells (t=6.127, P<0.01, t=12.579, P<0.01), The expression of tetrasoanin mRNA in L-OHP-SW620 cell line was higher than that in SW620 cell line (t=9.085, P< 0.01). The early apoptosis rate of L-OHP-SW620 cells in XCT790 group after XCT790 inhibited ERR -αexpression was higher than that in NC group (t=3.297, P< 0.01). The survival rate of XCT790 group after 72 h culture was (45.264±6.249)%, lower than that of NC group ( (63.364±9.472)%) (t=4.537, P<0.01). Compared with NC group, p-AKT protein was up-regulated(t=8.139, P<0.01), ERRα protein was down-regulated(t=6.452, P<0.01), the apoptosis rate was(17.541±2.317)%, lower than that in the sitetrasoanin group ((32.892±3.296)%) (t=4.526, P<0.01), the survival in sitetrasoanin group after 72 h culture was (49.653±5.945)%, lower than that in NC group((67.376±7.934)%) (t=3.109, P<0.05). Conclusion Tetrasoanin down-regulation and p-AKT protein up-regulation decreases ERRα protein and OHP-resistant colon cell proliferation is decreased, apoptosis is increased and drug resistance is decreased. Key words: Tetrasoanin; Chemo-resistant; Colon cancer; Small interfere RNA

Resistin Regulates Fatty Acid Β Oxidation by Suppressing Expression of Peroxisome Proliferator Activator Receptor Gamma-Coactivator 1α (PGC-1α)

Background/Aims: Abnormal fatty acid β oxidation has been associated with obesity and type 2 diabetes. Resistin is an adipokine that has been considered as a potential factor in obesity-mediated insulin resistance and type 2 diabetes. However, the effect of resistin on fatty acid β oxidation needs to be elucidated. Methods: We detected the effects of resistin on the expression of fatty acid oxidation (FAO) transcriptional regulatory genes, the fatty acid transport gene, and mitochondrial β-oxidation genes using real-time PCR. The rate of FAO was measured using ¹⁴C-palmitate. Immunofluorescence assay and western blot analysis were used to explore the underlying molecular mechanisms. Results: Resistin leads to a reduction in expression of the FAO transcriptional regulatory genes ERRα and NOR1, the fatty acid transport gene CD36, and the mitochondrial β-oxidation genes CPT1, MCAD, and ACO. Importantly, treatment with resistin led to a reduction in the rate of cellular fatty acid oxidation. In addition, treatment with resistin reduced phosphorylation of acetyl CoA carboxylase (ACC) (inhibitory). Mechanistically, resistin inhibited the activation of CREB, resulting in suppression of PGC-1α. Importantly, overexpressing PGC-1α can rescue the inhibitory effects of resistin on fatty acid β oxidation. Conclusions: Activating the transcriptional activity of CREB using small molecular chemicals is a potential pharmacological strategy for preventing the inhibitory effects of resistin on fatty acid β oxidation.

Identification of Estrogen-Related Receptor α Agonists in the Tox21 Compound Library.

The estrogen-related receptor α (ERRα) is an orphan nuclear receptor (NR) that plays a role in energy homeostasis and controls mitochondrial oxidative respiration. Increased expression of ERRα in certain ovarian, breast, and colon cancers has a negative prognosis, indicating an important role for ERRα in cancer progression. An interaction between ERRα and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) has also recently been shown to regulate an enzyme in the β-oxidation of free fatty acids, thereby suggesting that ERRα plays an important role in obesity and type 2 diabetes. Therefore, it would be prudent to identify compounds that can act as activators of ERRα. In this study, we screened ∼10,000 (8311 unique) compounds, known as the Tox21 10K collection, to identify agonists of ERRα. We performed this screen using two stably transfected HEK 293 cell lines, one with the ERRα-reporter alone and the other with both ERRα-reporter and PGC-1α expression vectors. After the primary screening, we identified more than five agonist clusters based on compound structural similarity analysis (e.g., statins). By examining the activities of the confirmed ERRα modulators in other Tox21 NR assays, eliminating those with promiscuous NR activity, and performing follow-up assays (e.g., small interfering RNA knockdown), we identified compounds that might act as endocrine disrupters through effects on ERRα signaling. To our knowledge, this study is the first comprehensive analysis in discovering potential endocrine disrupters that affect the ERRα signaling pathway.

IL-8 Is Involved in Estrogen-Related Receptor α-Regulated Proliferation and Migration of Colorectal Cancer Cells.

Studies revealed that estrogenic signals were involved in the development of colorectal cancer (CRC), while the roles of estrogen related receptor (ERR) on the progression of CRC have not been well illustrated. Its roles on the development of CRC were investigated. The expression of ERRα/β/γ in CRC cells were measured. The effects of ERRα on cell proliferation, migration and expression of cytokines were investigated accordingly. Our data revealed that the expression of ERRα, while not ERRβ or ERRγ, was significantly increased in CRC cells and clinical CRC tissues. Both the inverse agonist of ERRα (XCT-790) and si-ERRα can inhibit the proliferation of CRC cells. XCT-790 treatment can also suppress the wound healing and in vitro migration of CRC cells. Cytokine assays showed that XCT-790 can significantly decrease the expression of interleukin-8 (IL-8), while not IL-4, IL-6, IL-8, IL-9, IL-10, IL-18, IFN-γ, or TGF-β, in CRC cells. Over expression of ERRα increased the expression of IL-8. Luciferase assay showed XCT-790 decreased the promoter activity of IL-8. XCT-790 can increase the decay of IL-8 mRNA in SW480 cells. The recombinant IL-8 (rIL-8) can rescue XCT-790 induced suppression of proliferation and migration of CRC cells. XCT-790 can decrease the phosphorylation of ERK1/2 and STAT3, two downstream signal molecules of IL-8, in CRC cells. While rIL-8 can markedly attenuate XCT-790 induced dephosphorylation of ERK1/2 and STAT3. Our data showed that ERRα can trigger the proliferation and migration of CRC cells via up regulation of IL-8. Therefor targeted inhibition of ERRα/IL-8 might be a potential approach for CRC treatment and drug development.

ERR\u03b1 regulates the growth of triple-negative breast cancer cells via S6K1-dependent mechanism

Estrogen-related receptor alpha (ERRα) is an orphan nuclear factor that is a master regulator of cellular energy metabolism. ERRα is overexpressed in a variety of tumors, including ovarian, prostate, colorectal, cervical and breast, and is associated with a more aggressive tumor and a worse outcome. In breast cancer, specifically, high ERRα expression is associated with an increased rate of recurrence and a poor prognosis. Because of the common functions of ERRα and the mTORC1/S6K1 signaling pathway in regulation of cellular metabolism and breast cancer pathogenesis, we focused on investigating the biochemical relationship between ERRα and S6K1. We found that ERRα negatively regulates S6K1 expression by directly binding to its promoter. Downregulation of ERRα expression sensitized ERα-negative breast cancer cells to mTORC1/S6K1 inhibitors. Therefore, our results show that combinatorial inhibition of ERRα and mTORC1/S6K1 may have clinical utility in treatment of triple-negative breast cancer, and warrants further investigation.

Perinatal testosterone exposure potentiates vascular dysfunction by ERβ suppression in endothelial progenitor cells.

Recent clinical cohort study shows that testosterone therapy increases cardiovascular diseases in men with low testosterone levels, excessive circulating androgen levels may play a detrimental role in the vascular system, while the potential mechanism and effect of testosterone exposure on the vascular function in offspring is still unknown. Our preliminary results showed that perinatal testosterone exposure in mice induces estrogen receptor β (ERβ) suppression in endothelial progenitor cells (EPCs) in offspring but not mothers, while estradiol (E2) had no effect. Further investigation showed that ERβ suppression is due to perinatal testosterone exposure-induced epigenetic changes with altered DNA methylation on the ERβ promoter. During aging, EPCs with ERβ suppression mobilize to the vascular wall, differentiate into ERβ-suppressed mouse endothelial cells (MECs) with downregulated expression of SOD2 (mitochondrial superoxide dismutase) and ERRα (estrogen-related receptor α). This results in reactive oxygen species (ROS) generation and DNA damage, and the dysfunction of mitochondria and fatty acid metabolism, subsequently potentiating vascular dysfunction. Bone marrow transplantation of EPCs that overexpressed with either ERβ or a SIRT1 single mutant SIRT1-C152(D) that could modulate SIRT1 phosphorylation significantly ameliorated vascular dysfunction, while ERβ knockdown worsened the problem. We conclude that perinatal testosterone exposure potentiates vascular dysfunction through ERβ suppression in EPCs.

Mitochondrial Effects of PGC-1alpha Silencing in MPP+ Treated Human SH-SY5Y Neuroblastoma Cells.

The dopaminergic neuron degeneration and loss that occurs in Parkinson’s disease (PD) has been tightly linked to mitochondrial dysfunction. Although the aged-related cause of the mitochondrial defect observed in PD patients remains unclear, nuclear genes are of potential importance to mitochondrial function. Human peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α) is a multi-functional transcription factor that tightly regulates mitochondrial biogenesis and oxidative capacity. The goal of the present study was to explore the potential pathogenic effects of interference by the PGC-1α gene on N-methyl-4-phenylpyridinium ion (MPP+)-induced SH-SY5Y cells. We utilized RNA interference (RNAi) technology to probe the pathogenic consequences of inhibiting PGC-1α in the SH-SY5Y cell line. Remarkably, a reduction in PGC-1α resulted in the reduction of mitochondrial membrane potential, intracellular ATP content and intracellular H2O2 generation, leading to the translocation of cytochrome c (cyt c) to the cytoplasm in the MPP+-induced PD cell model. The expression of related proteins in the signaling pathway (e.g., estrogen-related receptor α (ERRα), nuclear respiratory factor 1 (NRF-1), NRF-2 and Peroxisome proliferator-activated receptor γ (PPARγ)) also decreased. Our finding indicates that small interfering RNA (siRNA) interference targeting the PGC-1α gene could inhibit the function of mitochondria in several capacities and that the PGC-1α gene may modulate mitochondrial function by regulating the expression of ERRα, NRF-1, NRF-2 and PPARγ. Thus, PGC-1α can be considered a potential therapeutic target for PD.

Local muscle cooling does not impact expression of mitochondrial-related genes

Recovery that takes place in a cold environment after endurance exercise elevates PGC-1α mRNA whereas ERRα and NRF2 mRNA expression are inhibited. However, the effect of local skeletal muscle cooling on mitochondrial-related gene expression is unknown. PurposeTo determine the impact of local skeletal muscle cooling during recovery from an acute bout of exercise on mitochondrial-related gene expression. MethodsRecreationally-trained male cyclists (n=8, age 25±3 y, height 181±6cm, weight 79±8kg, 12.8±3.6% body fat, VO2peak 4.52±0.88L·min−1 protocol) completed a 90-min variable intensity cycling protocol followed by 4h of recovery. During recovery, ice was applied intermittently to one leg (ICE) while the other leg served as a control (CON). Intramuscular temperature was recorded continuously. Muscle biopsies were taken from each vastus lateralis at 4h post-exercise for the analysis of mitochondrial-related gene expression. ResultsIntramuscular temperature was colder in ICE (26.7±1.1°C) than CON (35.5±0.1°C) throughout the 4h recovery period (p<0.001). There were no differences in expression of PGC-1α, TFAM, NRF1, NRF2, or ERRα mRNA between ICE and CON after the 4h recovery period. ConclusionLocal muscle cooling after exercise does not impact the expression of mitochondrial biogenesis-related genes compared to recovery from exercise in control conditions. When these data are considered with previous research, the stimuli for cold-induced gene expression alterations may be related to factors other than local muscle temperature. Additionally, different intramuscular temperatures should be examined to determine dose-response of mitochondrial-related gene expression.

Standardized Kaempferia parviflora Extract Inhibits Intrinsic Aging Process in Human Dermal Fibroblasts and Hairless Mice by Inhibiting Cellular Senescence and Mitochondrial Dysfunction.

Intrinsic skin aging is a complex biological phenomenon mainly caused by cellular senescence and mitochondrial dysfunction. This study evaluated the inhibitory effect of Kaempferia parviflora Wall ex. Baker ethanol extract (KPE) on H2O2-stimulated cellular senescence and mitochondrial dysfunction both in vitro and in vivo. KPE significantly increased cell growth and suppressed senescence-associated β-galactosidase activation. KPE inhibited the expression of cell-cycle inhibitors (p53, p21, p16, and pRb) and stimulated the expression of cell-cycle activators (E2F1 and E2F2). H2O2-induced hyperactivation of the phosphatidylinositol 3-kinase/protein kinase B (AKT) signaling pathway was suppressed by KPE through regulated expression of forkhead box O3a (FoxO3a) and mammalian target of rapamycin (mTOR). KPE attenuated inflammatory mediators (interleukin-6 (IL-6), IL-8, nuclear factor kappa B (NF-κB), and cyclooxygenase-2 (COX-2)) and increased the mRNA expression of PGC-1α, ERRα, NRF1, and Tfam, which modulate mitochondrial biogenesis and function. Consequently, reduced ATP levels and increased ROS level were also reversed by KPE treatment. In hairless mice, KPE inhibited wrinkle formation, skin atrophy, and loss of elasticity by increasing the collagen and elastic fibers. The results indicate that KPE prevents intrinsic aging process in hairless mice by inhibiting cellular senescence and mitochondrial dysfunction, suggesting its potential as a natural antiaging agent.

Hypoxic Exercise Training Promotes apelin/APJ Expression in Skeletal Muscles of High Fat Diet-Induced Obese Mice.

Apelin, an endogenous ligand of the G-protein-coupled receptor APJ, is a novel myokine and may play a key role in regulating energy metabolism. The purpose of the present study was to investigate the effects of hypoxic exposure, exercise, and hypoxic exercise training on the expression of apelin and APJ in skeletal muscle of obese mice. Sixty two-months old C57BL/6J mice were randomly divided into two groups: Ten in normal diet group (N) and 50 in the high fat diet (HFD) groups. After two months of feeding, the HFD mice, whose body weight was 20% higher than the average weight of the N group, were selected as obese mice and further allocated into four groups: Control (C), Exercise (E), Hypoxia (H), and Exercise plus Hypoxia (E+H), at 8-9 mice/group. Besides body weight, measured variables in skeletal muscle were protein/mRNA levels of apelin/APJ, AMPKα-Thr172 phosphorylation, hypoxia inducible factor-1α (HIF-1α), mRNA levels of peroxisome proliferator-activated receptor α (PPARα), estrogen-related receptor (ERRα), and nuclear respiratory factor 1 (NRF1). Obese mice had significantly lower mRNA and protein expressions of apelin/ APJ in skeletal muscles than the normal body weight mice. After four weeks of interventions, hypoxic exercise training decreased body weight and increased mRNA and protein expressions of apelin and APJ, mRNA expression of ERRα, and protein expression of HIF-1α. These results indicate that changes of body weight may be associated with the levels of apelin/APJ expressions in skeletal muscle.