BPA Differentially Regulates NPY Expression in Hypothalamic Neurons Through a Mechanism Involving Oxidative Stress

Endocrinology ◽  
2020 ◽  
Vol 161 (11) ◽  
Author(s):  
Neruja Loganathan ◽  
Emma K McIlwraith ◽  
Denise D Belsham

Abstract Bisphenol A (BPA), a ubiquitous endocrine-disrupting chemical, interferes with reproduction and is also considered an obesogen. The neuropeptide Y (NPY) neurons of the hypothalamus control both food intake and reproduction and have emerged as potential targets of BPA. These functionally diverse subpopulations of NPY neurons are differentially regulated by peripheral signals, such as estrogen and leptin. Whether BPA also differentially alters Npy expression in subpopulations of NPY neurons, contributing to BPA-induced endocrine dysfunction is unclear. We investigated the response of 6 immortalized hypothalamic NPY-expressing cell lines to BPA treatment. BPA upregulated Npy mRNA expression in 4 cell lines (mHypoA-59, mHypoE-41, mHypoA-2/12, mHypoE-42), and downregulated Npy in 2 lines (mHypoE-46, mHypoE-44). This differential expression of Npy occurred concurrently with differential expression of estrogen receptor mRNA levels. Inhibition of G-protein coupled estrogen receptor GPR30 or estrogen receptor β prevented the BPA-mediated decrease in Npy, whereas inhibition of energy sensor 5′ adenosine monophosphate-activated protein kinase (AMPK) with compound C prevented BPA-induced increase in Npy. BPA also altered neuroinflammatory and oxidative stress markers in both mHypoA-59 and mHypoE-46 cell lines despite the differential regulation of Npy. Remarkably, treatment with BPA in an antioxidant-rich media, Neurobasal A (NBA), or with reactive oxygen species scavenger tauroursodeoxycholic acid mitigated the BPA-induced increase and decrease in Npy. Furthermore, 2 antioxidant species from NBA—N-acetylcysteine and vitamin B6—diminished the induction of Npy in the mHypoA-59 cells, demonstrating these supplements can counteract BPA-induced dysregulation in certain subpopulations. Overall, these results illustrate the differential regulation of Npy by BPA in neuronal subpopulations, and point to oxidative stress as a pathway that can be targeted to block BPA-induced Npy dysregulation in hypothalamic neurons.

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Hideyuki Sasaki ◽  
Hiroshi Asanuma ◽  
Masashi Fujita ◽  
Hiroyuki Takahama ◽  
Masanori Asakura ◽  
...  

Background; Several studies have shown that metformin activates AMP-activated protein kinase (AMPK), which mediates potent cardioprotection against ischemia-reperfusion injury. AMPK is also activated in experimental failing myocardium, suggesting that activation of AMPK is beneficial for the pathophysiology of heart failure. We investigated whether metformin prevents oxidative stress-induced cell death in rat cardiomyocytes and attenuates the progression of heart failure in dogs. Methods and Results; The treatment with metformin (10 μmol/L) protected the rat cultured cardiomyocytes against cell death due to H 2 O 2 exposure (50 μmol/L) as indicated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), TUNEL staining, and flow cytometry. These effects were blunted by an AMPK inhibitor, compound-C (20 μmol/L), suggesting that the activation of AMPK decreased the extent of apoptosis-induced cell death due to H 2 O 2 exposure. Continuous rapid ventricular pacing (230/min for 4 weeks) in dogs caused heart failure and the treatment with metformin (100 mg/kg/day PO, n=8) decreased left ventricular (LV) end-diastolic dimension (32.8±0.4 vs. 36.5±1.0 mm, p< 0.01) and pressure (11.8±1.1 vs. 22±0.9 mmHg, p< 0.01), and increased LV fractional shortening (18.6±1.8 vs. 9.6±0.7 %, p< 0.01) along with enhanced phosphorylation of AMPK and the decreased the number of TUNEL-positive cells of the LV myocardium compared with the vehicle group (n=8). Interestingly, metformin increased the protein and mRNA levels of endothelial nitric oxide synthase of the LV myocardium and plasma nitric oxide levels. Metformin improved the plasma insulin resistance without increased myocardial GLUT-4 translocation. Furthermore, the subcutaneous administration of AICAR (50 mg/kg/every other day), another AMPK activator mediated the equivalent effects to metformin, strengthening the pivotal role of AMPK in reduction of apoptosis and prevention of heart failure. Conclusions; Activation of myocardial AMPK attenuated the oxidative stress-induced cardiomyocyte apoptosis and prevented the progression of heart failure in dogs, along with eNOS activation. Thus, metformin or AICAR may be applicable as a novel therapy for heart failure.


Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 787
Author(s):  
Enrique García-Pérez ◽  
Dojin Ryu ◽  
Hwa-Young Kim ◽  
Hae Dun Kim ◽  
Hyun Jung Lee

Ochratoxin A (OTA) is a mycotoxin that is potentially carcinogenic to humans. Although its mechanism remains unclear, oxidative stress has been recognized as a plausible cause for the potent renal carcinogenicity observed in experimental animals. The effect of OTA on oxidative stress parameters in two cell lines of LLC-PK1 and HK-2 derived from the kidneys of pig and human, respectively, were investigated and compared. We found that the cytotoxicity of OTA on LLC-PK1 and HK-2 cells was dose- and time-dependent in both cell lines. Furthermore, increased intracellular reactive oxygen species (ROS) induced by OTA in both cell lines were observed in a time-dependent manner. Glutathione (GSH) was depleted by OTA at >48 h in HK-2 but not in LLC-PK1 cells. While the mRNA levels of glucose-6-phosphate dehydrogenase (G6PD) and glutathione peroxidase 1 (GPX1) in LLC-PK1 were down-regulated by 0.67- and 0.66-fold, respectively, those of catalase (CAT), glutathione reductase (GSR), and superoxide dismutase 1 (SOD) in HK-2 were up-regulated by 2.20-, 2.24-, and 2.75-fold, respectively, after 72 h exposure to OTA. Based on these results, we conclude that HK-2 cells are more sensitive to OTA-mediated toxicity than LLC-PK1, and OTA can cause a significant oxidative stress in HK-2 as indicated by changes in the parameter evaluated.


2021 ◽  
Vol 28 (5) ◽  
pp. 4080-4092
Author(s):  
Takahiro Ichikawa ◽  
Masahiro Shibata ◽  
Takahiro Inaishi ◽  
Ikumi Soeda ◽  
Mitsuro Kanda ◽  
...  

Background: Accumulating evidence indicates tumor-promoting roles of synaptotagmin 13 (SYT13) in several cancers; however, no studies have investigated its expression in breast cancer (BC). This study aimed to clarify the significance of SYT13 in BC. Methods: SYT13 mRNA expression levels were evaluated in BC cell lines. Polymerase chain reaction (PCR) array analysis was conducted to determine the correlation between expression levels of SYT13 and other tumor-associated genes. Then, the association of SYT13 expression levels in the clinical BC specimens with patients’ clinicopathological factors was evaluated. These findings were subsequently validated using The Cancer Genome Atlas (TCGA) database. Results: Among 13 BC cell lines, estrogen receptor (ER)-positive cells showed higher SYT13 mRNA levels than ER-negative cells. PCR array analysis revealed positive correlations between SYT13 and several oncogenes predominantly expressed in ER-positive BC, such as estrogen receptor 1, AKT serine/threonine kinase 1, and cyclin-dependent kinases 4. In 165 patients, ER-positive specimens exhibited higher SYT13 mRNA expression levels than ER-negative specimens. The TCGA database analysis confirmed that patients with ER-positive BC expressed higher SYT13 levels than ER-negative patients. Conclusion: This study suggests that SYT13 is highly expressed in ER-positive BC cells and clinical specimens, and there is a positive association of SYT13 with the ER signaling pathways.


2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Wei Zhu ◽  
Zhijian Zhao ◽  
Fu-Ju Chou ◽  
Li Zuo ◽  
Tongzu Liu ◽  
...  

Females develop kidney stones less frequently than males do. However, it is unclear if this gender difference is related to altered estrogen/estrogen receptor (ER) signaling. Here, we found that ER beta (ERβ) signals could suppress hepatic oxalate biosynthesis via transcriptional upregulation of the glyoxylate aminotransferase (AGT1) expression. Results from multiple in vitro renal cell lines also found that ERβ could function via suppressing the oxalate-induced injury through increasing the reactive oxygen species (ROS) production that led to a decrease of the renal calcium oxalate (CaOx) crystal deposition. Mechanism study results showed that ERβ suppressed oxalate-induced oxidative stress via transcriptional suppression of the NADPH oxidase subunit 2 (NOX2) through direct binding to the estrogen response elements (EREs) on the NOX2 5′ promoter. We further applied two in vivo mouse models with glyoxylate-induced renal CaOx crystal deposition and one rat model with 5% hydroxyl-L-proline-induced renal CaOx crystal deposition. Our data demonstrated that mice lacking ERβ (ERβKO) as well as mice or rats treated with ERβ antagonist PHTPP had increased renal CaOx crystal deposition with increased urinary oxalate excretion and renal ROS production. Importantly, targeting ERβ-regulated NOX2 with the NADPH oxidase inhibitor, apocynin, can suppress the renal CaOx crystal deposition in the in vivo mouse model. Together, results from multiple in vitro cell lines and in vivo mouse/rat models all demonstrate that ERβ may protect against renal CaOx crystal deposition via inhibiting the hepatic oxalate biosynthesis and oxidative stress-induced renal injury.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2737-2737
Author(s):  
Richard A. Wells ◽  
Chunhong Gu ◽  
Joelle dela Paz

Abstract Abstract 2737 Poster Board II-713 Background Although patients with acute myelogenous leukaemia (AML) typically respond well to initial therapy, with over 75% of patients achieving complete remission, in the great majority the disease ultimately relapses. This is thought to be due to the inherent resistance of leukaemia stem cells to the effects of chemotherapy. While some mechanisms of chemoresistance, e.g. TP53 mutation and upregulation of P-glycoprotein expression, have been well characterized, this phenomenon remains incompletely understood and is a significant barrier to improving patient outcomes. Methods and results The thiazolidindione drug troglitazone (TG) induces apoptosis in AML cells via generation of intracellular reactive oxygen species (ROS), but the degree of sensitivity to TG is highly heterogeneous among AML cell lines. We studied expression of the transcription factor ARNT (aryl hydrocarbon nuclear translocator) in TG-sensitive and TG-resistant AML cell lines following TG treatment. In HL-60 cells, which are highly sensitive to induction of apoptosis by TG, ARNT mRNA levels remained constant following TG treatment and ARNT protein levels markedly decreased, while in U937 cells, which are TG resistant, ARNT mRNA levels increased and ARNT protein levels remained constant. We then tested the effect of exogenous expression of ARNT on the sensitivity of HL-60 cells to TG-induced apoptosis. HL-60 cells transduced with a retrovirus expressing ARNT became TG-resistant. Exogenous expression of ARNT also conferred resistance to induction of apoptosis by hydrogen peroxide, daunorubicin and etoposide. The cellular response to oxidative stress is governed by intracellular signaling pathways and through a transcriptional response through which expression of antioxidant genes is coordinated. HL-60 cells expressing ARNT had striking constitutive activation of AKT signaling, and treatment of these cells with a specific inhibitor of AKT signaling reversed their resistance to TG-induced apoptosis. The activation of AKT signaling by ARNT appears to be mediated by downregulation of expression of PP2A and alpha4, two key negative regulators of AKT phosphorylation. In addition, ARNT-transduced HL-60 cells showed increased expression of Nrf2, a key transcriptional regulator of the antioxidant response, and its target genes SOD2 and CAT. Conclusions The response to oxidative stress is heterogeneous in AML cells lines, and varies with expression of ARNT. ARNT activates expression of Nrf2, which stimulates expression of antioxidant genes resulting in an augmented adaptive response to ROS. Unexpectedly, ARNT also activates AKT signaling by repressing expression of the regulatory phosphatases PP2A and alpha4. These activities of ARNT result in increased resistance to the induction of apoptosis by TG, hydrogen peroxide, and chemotherapy. ARNT may play an important role in chemoresistance in and may be useful as a predictive or prognostic biomarker. Disclosures: No relevant conflicts of interest to declare.


Author(s):  
Dao-ming Zhang ◽  
Jun-jian Deng ◽  
Yao-gui Wu ◽  
Tian Tang ◽  
Lin Xiong ◽  
...  

Objectives: Radiotherapy improves the survival rate of cancer patients, yet it also involves some inevitable complications. Radiation-induced heart disease (RIHD) is one of the most serious complications, especially the radiotherapy of thoracic tumors, which is characterized by cardiac oxidative stress disorder and programmed cell death. At present, there is no effective treatment strategy for RIHD; in addition, it cannot be reversed when it progresses. This study aims to explore the role and potential mechanism of microRNA-223-3p (miR-223-3p) in RIHD.Methods: Mice were injected with miR-223-3p mimic, inhibitor, or their respective controls in the tail vein and received a single dose of 20 Gy whole-heart irradiation (WHI) for 16 weeks after 3 days to construct a RIHD mouse model. To inhibit adenosine monophosphate activated protein kinase (AMPK) or phosphodiesterase 4D (PDE4D), compound C (CompC) and AAV9-shPDE4D were used.Results: WHI treatment significantly inhibited the expression of miR-223-3p in the hearts; furthermore, the levels of miR-223-3p decreased in a radiation time-dependent manner. miR-223-3p mimic significantly relieved, while miR-223-3p inhibitor aggravated apoptosis, oxidative damage, and cardiac dysfunction in RIHD mice. In addition, we found that miR-223-3p mimic improves WHI-induced myocardial injury by activating AMPK and that the inhibition of AMPK by CompC completely blocks these protective effects of miR-223-3p mimic. Further studies found that miR-223-3p lowers the protein levels of PDE4D and inhibiting PDE4D by AAV9-shPDE4D blocks the WHI-induced myocardial injury mediated by miR-223-3p inhibitor.Conclusion: miR-223-3p ameliorates WHI-induced RIHD through anti-oxidant and anti-programmed cell death mechanisms via activating AMPK by PDE4D regulation. miR-223-3p mimic exhibits potential value in the treatment of RIHD.


2021 ◽  
Author(s):  
Congcong Wang ◽  
Lei Wang ◽  
Chengmeng Huang ◽  
Yungang Liu ◽  
Hongxuan Kuang ◽  
...  

Abstract BackgroundBisphenol A (BPA) is an additive in polycarbonate and epoxy resin particles with endocrine disrupting effects. Previously it has been reported that BPA is neurotoxic via induction of cell apoptosis and inflammation, and our recent studies showed that even at nanomolar concentrations BPA accelerated the apoptosis and death of human neuroblastoma cells from both genders, whose mechanisms remain, however, unidentified.ResultsHuman neuroblastoma cell lines developed from male and female subjects, IMR-32 and SK-N-SH, respectively, were exposed to BPA at concentrations ranging from 1 nM to 100 μM, for 24 h, with or without epigallocatechin gallate (EGCG, 4 or 8 μM), Z-YVAD-FMK (1 or 10 μM, caspase-1 inhibitor), and ICI182.780 (100 nM or 3 μM, estrogen receptor inhibitor) as modulators. The results showed that BPA nonlinearly upregulated the levels of IL-18, ASC, GSDMD and NLRP3 mRNAs and that of NLRP3, caspase-1, GSDMD and IL-1β proteins in IMR-32 and SK-N-SH cells. Noticeably, the mRNA levels of caspase-1 and IL-1β were changed differently in the two cell lines: the level of caspase-1 mRNA was enhanced in IMR-32 cells but suppressed in SK-N-SH cells, and that of IL-1β was suppressed in IMR-32 cells but enhanced in SK-N-SH cells. The level of GSDMD expression in situ was along with the increase in the release of IL-1β, IL-18, caspase-1 and lactate dehydrogenase (LDH). Additionally, Z-YVAD-FMK, ICI182.780 and EGCG significantly reversed the changes of the above mRNAs/proteins induced by BPA. BPA significantly reduced the level of the reactive oxygen species and the rate of LDH leakage and apoptosis, while obviously increased the cell viability and the mitochondrial membrane potential. Meanwhile, Z-YVAD-FMK and ICI182.780 abruptly reduced the levels of Bak1, Bax, Bcl-2 and caspase-3 proteins induced by BPA. ConclusionAs mediated by the estrogen receptor, BPA may induce the pyroptosis of neuroblastoma cells through NLRP3/caspase-1/GSDMD signaling pathway, and caspase-1-dependent pyroptosis may be involved in BPA-induced apoptosis, which is alleviated by EGCG, an anti-oxidation agent.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3722-3722
Author(s):  
Ioanna Chiotoglou ◽  
Tatjana Smilevska ◽  
Kostas Stamatopoulos ◽  
Maria Samara ◽  
Sophia Likousi ◽  
...  

Abstract Transferrin receptor 1 (TfR1, CD71) expression is related to the proliferative state of the cells as well as the induction of differentiation; furthermore, CD71 is one of the “classical” activation markers up-regulated upon B-cell activation. As we have recently shown (Smilevska et al., Leuk Res 2005, in press), CLL is characterized by almost uniformly high CD71 expression, regardless of IGH mutational load; this is in keeping with the activated status of neoplastic cells. In the present study, we evaluated TfR1 expression at the mRNA and protein level in CD19+ B cells sorted from peripheral blood mononuclear cells of two healthy donors, 37 patients with typical chronic lymphocytic leukemia (CLL), as well as the BV173 (B cell acute lymphoblastic leukemia) and EHEB (human chronic B cell leukemia) cell lines. In all CLL cases, the tumor load was at least 70%. Twenty-two out of 37 CLL cases (59%) carried IGHV genes with &lt;98% homology to the closest germline gene (“mutated”); the remainder (15/37, 41%) carried “unmutated” IGHV genes. TfR1 cDNA sequences were detected by RT-PCR in all cell samples using primers specific for TfR1 gene exons 15–17. Real-time PCR analysis (using h-HPRT as a housekeeping gene) revealed low TfR1 mRNA transcripts in both cell lines (relative TfR1/h-HPRT ratios for BV173/EHEB cells: 0.05/0.08), contrasting normal peripheral blood CD19+ B cells, which on average had a 1-log higher concentration (relative TfR1/h-HPRT ratios: 0.995). TfR1 mRNA levels were widely divergent in CLL samples (relative TfR1/h-HPRT ratios: 0.23–13.3); no statistically significant associations were identified with IGH mutation status. Cell lysates were separated by SDS-polyacrylamide gel electrophoresis, electroblotted onto the nitrocellulose filters for probing with anti-TfR1-specific antibody and actin polyclonal antibody (control); quantitative gel banding densitometry was performed using with Epson GT-8000 Laser scanner. TfR1 protein levels were similar in CD19+ peripheral blood normal B cells as well as malignant cell lines (CD19: 1.16, BV173: 1.16, EHEB: 1.12), although CLL samples showed greater individual variation (0.4–2); median values were not different from either normal B cells or B cell lines. CD71 expression was also studied by flow cytometry in 20/37 CLL cases; all analyzed cases were CD71-positive with a generally high percentage of CD71-expressing neoplastic cells (median 91%, range: 28.3–100.0%); based on staining intensity, 18/20 CD71 (+) cases had bright fluorescence intensity, whereas the remainder (2/20) had low fluorescence intensity (dim). These results allude to differential regulation of TfR1 expression in normal vs. malignant B cells. In normal B cells, transcriptional mechanisms exert an important control over TfR1 expression. In malignant B cells (primary cells or established cell lines), similar levels of TfR1 (CD71) protein in the context of widely divergent TfR1 mRNA levels might be attributed to the operation of post-transcriptional mechanisms (perhaps increased mRNA stability).


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Hesham M. Korashy ◽  
Zaid H. Maayah ◽  
Adel R. Abd-Allah ◽  
Ayman O. S. El-Kadi ◽  
Abdulqader A. Alhaider

Few published studies have reported the use of crude camel milk in the treatment of stomach infections, tuberculosis and cancer. Yet, little research was conducted on the effect of camel milk on the apoptosis and oxidative stress associated with human cancer. The present study investigated the effect and the underlying mechanisms of camel milk on the proliferation of human cancer cells using anin vitromodel of human hepatoma (HepG2) and human breast (MCF7) cancer cells. Our results showed that camel milk, but not bovine milk, significantly inhibited HepG2 and MCF7 cells proliferation through the activation of caspase-3 mRNA and activity levels, and the induction of death receptors in both cell lines. In addition, Camel milk enhanced the expression of oxidative stress markers, heme oxygenase-1 and reactive oxygen species production in both cells. Mechanistically, the increase in caspase-3 mRNA levels by camel milk was completely blocked by the transcriptional inhibitor, actinomycin D; implying that camel milk increasedde novoRNA synthesis. Furthermore, Inhibition of the mitogen activated protein kinases differentially modulated the camel milk-induced caspase-3 mRNA levels. Taken together, camel milk inhibited HepG2 and MCF7 cells survival and proliferation through the activation of both the extrinsic and intrinsic apoptotic pathways.


2018 ◽  
Vol 107 (4) ◽  
pp. 387-399 ◽  
Author(s):  
Stephanie M. Kim ◽  
Emma K. McIlwraith ◽  
Jennifer A. Chalmers ◽  
Denise D. Belsham

Background and Objectives: Elevated levels of saturated fatty acids (SFA) induce a state of neuroinflammation in the hypothalamus. It has been suggested that microglia sense palmitate, a prevalent circulating SFA, and act as mediators of this inflammatory process by communicating with neurons, particularly those involved in appetite regulation. In this study, we examined the inflammatory response to palmitate in immortalized microglial cell lines, BV-2 and IMG, and the subsequent effects on inflammatory gene expression in a model of NPY/AgRP neurons, mHypoE-46. Methods: The BV-2 cells were treated with 50 µM palmitate for 4 and 24 h, and the transcriptional regulation of markers for inflammation and cellular stress was assessed using an RT2 Profiler PCR Array. Select genes were verified with qRT-PCR. The BV-2 and IMG cells were then co-cultured using 1.0-µm cell culture inserts with an immortalized hypothalamic cell line, mHypoE-46, to investigate potential intercellular communication between microglia and neurons. Results: We found that palmitate increased the mRNA levels of specific inflammatory genes, and a general anti-inflammatory profile was revealed in the microglia cells. The mRNA changes in TNFα at 4 and 24 h in BV-2 cells were abrogated with the toll-like receptor 4 (TLR4) inhibitor, TAK-242, indicating the involvement of TLR4. Co-culture of mHypoE-46 neurons with microglia pre-treated with palmitate resulted in repression of TNFα expression in the hypothalamic neurons. As palmitate significantly increased IL-13 expression in microglia, the effect of this cytokine was tested in mHypoE-46 neurons. The addition of IL-13 to neuronal cultures normalized the palmitate-mediated increase in IL-6 and AgRP expression, suggesting that microglia may protect surrounding neurons, at least in part, through the release of IL-13. Conclusions: These results suggest a potential anti-inflammatory role of microglia towards the palmitate-induced neuroinflammation, and potentially energy homeostasis, in hypothalamic neurons.


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