scholarly journals Sodium 4-Phenylbutyrate Protects Hypoxic-Ischemic Brain Injury via Attenuating Endoplasmic Reticulum Stress in Neonatal Rats

2021 ◽  
Vol 15 ◽  
Author(s):  
Ziyi Wu ◽  
Jiayuan Niu ◽  
Hang Xue ◽  
Shuo Wang ◽  
Ping Zhao

Neonatal hypoxic-ischemic (HI) brain injury is associated with long-term neurological disorders, and protective strategies are presently scarce. Sodium 4-phenylbutyrate (4-PBA) reportedly acts as a chemical chaperone that alleviates endoplasmic reticulum (ER) stress, which plays a critical role in neurological diseases. The present study aimed to evaluate the neuroprotective effects of 4-PBA on HI-induced neonatal brain injury in a rat model, and to characterize possible underlying mechanisms. The HI brain injury model was established by ligating the left common carotid artery in 7-day-old rats, followed by exposure to 8% oxygen for 2 h. The 4-PBA or vehicle was administered by an intracerebroventricular injection 30 min before HI. The protein expression levels of ER stress markers (GRP78, ATF6, and CHOP) were detected by western blotting at 24 h after HI insult. The activation of cAMP-response element-binding protein (CREB) was evaluated by western blotting and immunofluorescence. TUNEL and Nissl staining were performed to detect the histomorphological changes in the hippocampal neurons at 24 h and 7 days, respectively, after HI injury. From days 29 to 34 after brain HI, rats underwent Morris water maze tests to assess cognitive functioning. The results showed that pretreatment with 4-PBA decreased HI-induced excessive ER stress and neuronal injury. Moreover, CREB activation might be involved in the beneficial effects of 4-PBA on HI-induced learning and memory deficits in rats. In conclusion, the present study suggested a potential therapeutic approach of ER stress inhibition in the treatment of neonatal HI brain injury.

2021 ◽  
Author(s):  
Dinh Thi Nguyen ◽  
Thuong Manh Le ◽  
Tsuyoshi Hattori ◽  
Mika Takarada-Iemata ◽  
Hiroshi Ishii ◽  
...  

AbstractWhile ATF6α plays a central role in the endoplasmic reticulum (ER) stress response, the function of ATF6β is largely unknown. Here, we demonstrate that ATF6β is highly expressed in the hippocampus of the brain, and specifically regulates the expression of calreticulin, a molecular chaperone in the ER with a high Ca2+-binding capacity. Calreticulin expression was reduced to ~50% in the central nervous system of Atf6b−/− mice, and restored by ATF6β. Analysis using cultured hippocampal neurons revealed that ATF6β deficiency reduced Ca2+ stores in the ER and enhanced ER stress-induced death, which was rescued by ATF6β, calreticulin, Ca2+-modulating reagents such as BAPTA-AM and 2-APB, and ER stress inhibitor salubrinal. In vivo, kainate-induced neuronal death was enhanced in hippocampi of Atf6b−/− and Calr+/− mice, and restored by 2-APB and salubrinal. These results suggest that the ATF6β-calreticulin axis plays a critical role in the neuronal survival by improving Ca2+ homeostasis under ER stress.


2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Weilin Xu ◽  
Tao Li ◽  
Liansheng Gao ◽  
Jingwei Zheng ◽  
Jun Yan ◽  
...  

Abstract Background Neuroinflammation and oxidative stress play important roles in early brain injury following subarachnoid hemorrhage (SAH). This study is the first to show that activation of apelin receptor (APJ) by apelin-13 could reduce endoplasmic reticulum (ER)-stress-associated inflammation and oxidative stress after SAH. Methods Apelin-13, apelin siRNA, APJ siRNA, and adenosine monophosphate-activated protein kinase (AMPK) inhibitor-dorsomorphin were used to investigate if the activation of APJ could provide neuroprotective effects after SAH. Brain water content, neurological functions, blood-brain barrier (BBB) integrity, and inflammatory molecules were evaluated at 24 h after SAH. Western blotting and immunofluorescence staining were applied to assess the expression of target proteins. Results The results showed that endogenous apelin, APJ, and p-AMPK levels were significantly increased and peaked in the brain 24 h after SAH. In addition, administration of exogenous apelin-13 significantly alleviated neurological functions, attenuated brain edema, preserved BBB integrity, and also improved long-term spatial learning and memory abilities after SAH. The underlying mechanism of the neuroprotective effects of apelin-13 is that it suppresses microglia activation, prevents ER stress from overactivation, and reduces the levels of thioredoxin-interacting protein (TXNIP), NOD-like receptor pyrin domain-containing 3 protein (NLRP3), Bip, cleaved caspase-1, IL-1β, TNFα, myeloperoxidase (MPO), and reactive oxygen species (ROS). Furthermore, the use of APJ siRNA and dorsomorphin abolished the neuroprotective effects of apelin-13 on neuroinflammation and oxidative stress. Conclusions Exogenous apelin-13 binding to APJ attenuates early brain injury by reducing ER stress-mediated oxidative stress and neuroinflammation, which is at least partly mediated by the AMPK/TXNIP/NLRP3 signaling pathway.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Fusakazu Jo ◽  
Hiromi Jo ◽  
Aline M Hilzendeger ◽  
Martin D Cassell ◽  
D. T Rutkowski ◽  
...  

Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been identified as important contributors to neurological diseases and have been implicated in mediating hypothalamic inflammation and the hypertensive response to angiotensin II. We examined the role of ER stress and the UPR in the metabolic and fluid balance effects of brain angiotensin in two mouse models: 1) “sRA” transgenic mice (expressing human renin in neurons via the synapsin promoter crossed with human angiotensinogen via its own promoter), and 2) DOCA-salt treated C57BL/6J mice. Both DOCA-salt and sRA mice exhibit hyperactivity of the brain RAS, suppression of circulating RAS, hypertension, polydipsia, and an elevated resting metabolic rate. We examined the accumulation of UPR biomarker CCAAT-enhancer-binding protein homologous protein (CHOP) by immunocytochemistry in the brain of both models. CHOP is considered a marker of chronic ER stress. Increased CHOP immunoreactivity was evident in the subfornical organ (SFO) of sRA mice but was absent in non-transgenic (NT) and CHOP-/- mice. There was also increased CHOP immunoreactivity in the SFO of DOCA-salt mice compared with untreated controls. Next, we infused the ER stress-reducing chemical chaperone tauroursodeoxycholic acid (TUDCA, 5.28 ug/day, or aCSF vehicle) to assess if ER stress is mechanistically related to the hypertension, polydipsia, and elevated resting metabolic rate observed in both models. ICV TUDCA (3-5 day pretreatment then continuously for 3 wks) significantly attenuated the polydipsia (aCSF 20.7±0.9 vs TUDCA 10.8±1.0 mL/day, P<0.05) and metabolic rate (aCSF, 3.38±0.07 vs TUDCA 3.16±0.06 mL O2/100g/min, P<0.05) in the DOCA-salt model. ICV TUDCA (3 wks) had similar effects on the polydipsia in the sRA model (51±10% of aCSF control, P<0.05). DOCA-salt caused (P<0.05) increases in 24 hr mean arterial pressure (MAP) that were unaffected by ICV TUDCA (aCSF baseline 114±3 to 128±4 mmHg with DOCA-salt; TUDCA 117±7 to 129±4). Heart rate responses to DOCA-salt were attenuated (P<0.05) with ICV TUDCA (aCSF baseline 528±10 to 448±15 BPM with DOCA-salt; TUDCA 529±6 to 486±11). Together these data mechanistically implicate ER stress in the fluid and metabolic responses to increased brain RAS activity.


2017 ◽  
Vol 59 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Long The Nguyen ◽  
Sonia Saad ◽  
Yi Tan ◽  
Carol Pollock ◽  
Hui Chen

Maternal obesity has been shown to increase the risk of obesity and related disorders in the offspring, which has been partially attributed to changes of appetite regulators in the offspring hypothalamus. On the other hand, endoplasmic reticulum (ER) stress and autophagy have been implicated in hypothalamic neuropeptide dysregulation, thus may also play important roles in such transgenerational effect. In this study, we show that offspring born to high-fat diet-fed dams showed significantly increased body weight and glucose intolerance, adiposity and plasma triglyceride level at weaning. Hypothalamic mRNA level of the orexigenic neuropeptide Y (NPY) was increased, while the levels of the anorexigenic pro-opiomelanocortin (POMC), NPY1 receptor (NPY1R) and melanocortin-4 receptor (MC4R) were significantly downregulated. In association, the expression of unfolded protein response (UPR) markers including glucose-regulated protein (GRP)94 and endoplasmic reticulum DNA J domain-containing protein (Erdj)4 was reduced. By contrast, protein levels of autophagy-related genes Atg5 and Atg7, as well as mitophagy marker Parkin, were slightly increased. The administration of 4-phenyl butyrate (PBA), a chemical chaperone of protein folding and UPR activator, in the offspring from postnatal day 4 significantly reduced their body weight, fat deposition, which were in association with increased activating transcription factor (ATF)4, immunoglobulin-binding protein (BiP) and Erdj4 mRNA as well as reduced Parkin, PTEN-induced putative kinase (PINK)1 and dynamin-related protein (Drp)1 protein expression levels. These results suggest that hypothalamic ER stress and mitophagy are among the regulatory factors of offspring metabolic changes due to maternal obesity.


2017 ◽  
Vol 312 (5) ◽  
pp. L586-L598 ◽  
Author(s):  
Ru-Jeng Teng ◽  
Xigang Jing ◽  
Teresa Michalkiewicz ◽  
Adeleye J. Afolayan ◽  
Tzong-Jin Wu ◽  
...  

Rodent pups exposed to hyperoxia develop lung changes similar to bronchopulmonary dysplasia (BPD) in extremely premature infants. Oxidative stress from hyperoxia can injure developing lungs through endoplasmic reticulum (ER) stress. Early caffeine treatment decreases the rate of BPD, but the mechanisms remain unclear. We hypothesized that caffeine attenuates hyperoxia-induced lung injury through its chemical chaperone property. Sprague-Dawley rat pups were raised either in 90 (hyperoxia) or 21% (normoxia) oxygen from postnatal day 1 (P1) to postnatal day 10 (P10) and then recovered in 21% oxygen until P21. Caffeine (20 mg/kg) or normal saline (control) was administered intraperitoneally daily starting from P2. Lungs were inflation-fixed for histology or snap-frozen for immunoblots. Blood caffeine levels were measured in treated pups at euthanasia and were found to be 18.4 ± 4.9 μg/ml. Hyperoxia impaired alveolar formation and increased ER stress markers and downstream effectors; caffeine treatment attenuated these changes at P10. Caffeine also attenuated the hyperoxia-induced activation of cyclooxygenase-2 and markers of apoptosis. In conclusion, hyperoxia-induced alveolar growth impairment is mediated, in part, by ER stress. Early caffeine treatment protects developing lungs from hyperoxia-induced injury by attenuating ER stress.


BMJ Open ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. e015434 ◽  
Author(s):  
Eleonora Dalla Bella ◽  
Irene Tramacere ◽  
Giovanni Antonini ◽  
Giuseppe Borghero ◽  
Margherita Capasso ◽  
...  

IntroductionRecent studies suggest that endoplasmic reticulum stress may play a critical role in the pathogenesis of amyotrophic lateral sclerosis (ALS) through an altered regulation of the proteostasis, the cellular pathway-balancing protein synthesis and degradation. A key mechanism is thought to be the dephosphorylation of eIF2α, a factor involved in the initiation of protein translation. Guanabenz is an alpha-2-adrenergic receptor agonist safely used in past to treat mild hypertension and is now an orphan drug. A pharmacological action recently discovered is its ability to modulate the synthesis of proteins by the activation of translational factors preventing misfolded protein accumulation and endoplasmic reticulum overload. Guanabenz proved to rescue motoneurons from misfolding protein stress both in in vitro and in vivo ALS models, making it a potential disease-modifying drug in patients. It is conceivable investigating whether its neuroprotective effects based on the inhibition of eIF2α dephosphorylation can change the progression of ALS.Methods and analysesProtocolised Management In Sepsis is a multicentre, randomised, double-blind, placebo-controlled phase II clinical trial with futility design. We will investigate clinical outcomes, safety, tolerability and biomarkers of neurodegeneration in patients with ALS treated with guanabenz or riluzole alone for 6 months. The primary aim is to test if guanabenz can reduce the proportion of patients progressed to a higher stage of disease at 6 months compared with their baseline stage as measured by the ALS Milano-Torino Staging (ALS-MITOS) system and to the placebo group. Secondary aims are safety, tolerability and change in at least one biomarker of neurodegeneration in the guanabenz arm compared with the placebo group. Findings will provide reliable data on the likelihood that guanabenz can slow the course of ALS in a phase III trial.Ethics and disseminationThe study protocol was approved by the Ethics Committee of IRCCS ‘Carlo Besta Foundation’ of Milan (Eudract no. 2014-005367-32 Pre-results) based on the Helsinki declaration.


2020 ◽  
Vol 319 (6) ◽  
pp. E961-E980
Author(s):  
Ruixi Luo ◽  
Linzhao Li ◽  
Xiaohong Liu ◽  
Yujia Yuan ◽  
Wuzheng Zhu ◽  
...  

High levels of plasma free fatty acids (FFAs) lead to endothelial dysfunction (ED), which is involved in the pathogenesis of metabolic syndrome, diabetes, and atherosclerosis. Endoplasmic reticulum (ER) stress and endothelial-to-mesenchymal transition (EndMT) are demonstrated to be mechanistically related to endothelial dysfunction. Mesenchymal stem cells (MSCs) have exhibited an extraordinary cytoprotective effect on cellular lipotoxicity and vasculopathy. However, the underlying mechanisms have not been clearly defined. In the present study, we investigated whether MSCs could ameliorate palmitic acid (PA)-induced endothelial lipotoxicity by reducing ER stress and EndMT. We observed that MSC cocultures substantially alleviated PA-induced lipotoxicity in human umbilical vein endothelial cells (HUVECs). MSCs were able to restore the cell viability, increase tubule formation and migration ability, and decrease inflammation response and lipid deposition. Furthermore, PA caused endothelial-to-mesenchymal transition in HUVECs, which was abrogated by MSCs possibly through inhibiting ER stress. In addition, PA stimulated MSCs to secrete more stanniocalcin-1 (STC-1). Knocking down of STC-1 in MSCs attenuated their effects on PA-induced lipotoxicity in HUVECs. In vivo, MSC transplantation alleviated dyslipidemia and endothelial dysfunction in high-fat diet-fed Sprague–Dawley rats. MSC-treated rats showed reduced expressions of ER stress-related genes in aortas and suppressed expressions of EndMT-related proteins in rat aortic endothelial cells. Overall, our findings indicated that MSCs were able to attenuate endothelial lipotoxicity through inhibiting ER stress and EndMT, in which STC-1 secreted from MSCs may play a critical role.


2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Chunyue Wang ◽  
Xueying Cai ◽  
Ruochen Wang ◽  
Siyu Zhai ◽  
Yongfeng Zhang ◽  
...  

Abstract Background Endoplasmic reticulum (ER) stress is involved in the progression of Alzheimer’s disease (AD). Verbascoside (VB), an active phenylethanoid glycoside that was first isolated from Verbascum sinuatum (the wavyleaf mullein), possesses anti-inflammatory, antioxidative, and anti-apoptotic effects. The purpose of this study was to elucidate the beneficial effects of VB in amyloid β (Aβ)1–42-damaged human glioma (U251) cells and in APPswe/PSEN1dE9 transgenic (APP/PS1) mice. Methods U251 cells were co-incubated with 10 μM of Aβ1-42 and treated with VB. The protective effects of VB were investigated by using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay, flow cytometry, fluorescence staining, and transmission electron microscopy. APP/PS1 transgenic mice were treated for 6 weeks with VB. Learning and memory were evaluated using a Morris water maze test. Immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling, thioflavin-S staining, and proteomics analysis were performed to study the potential neuroprotective mechanism. Enzyme-linked immunosorbent assays and western blot were performed to analyze altered protein levels of brain lysates in APP/PS1 mice and/or Aβ1-42-damaged U251 cells. Results In Aβ1-42-damaged U251 cells, VB significantly improved cell viability, inhibited apoptosis, reduced calcium accumulation and the intracellular concentrations of reactive oxygen species, and improved the morphology of mitochondria and ER. In APP/PS1 mice, 6-week administration of VB significantly improved memory and cognition. VB inhibited apoptosis, reduced the deposition of Aβ, reduced the formation of neurofibrillary tangles formed by hyperphosphorylated tau protein, and downregulated the expression levels of 4-hydroxynonenal and mesencephalic astrocyte-derived neurotrophic factor in the brains of APP/PS1 mice. Proteomics analysis of mouse hippocampus suggested that the neuroprotective effect of VB may be related to the reduction of ER stress. This was indicated by the fact that VB inhibited the three branches of the unfolded protein response, thereby attenuating ER stress and preventing apoptosis. Conclusions The results confirmed that VB possesses significant neuroprotective effects, which are related to the reduction of ER stress. These findings support the status of VB as a potentially effective treatment for AD and warrant further research.


2018 ◽  
Vol 40 (2) ◽  
pp. 175-188 ◽  
Author(s):  
Michael J. Hylin ◽  
Ryan C. Holden ◽  
Aidan C. Smith ◽  
Aric F. Logsdon ◽  
Rabia Qaiser ◽  
...  

The leading cause of death in the juvenile population is trauma, and in particular neurotrauma. The juvenile brain response to neurotrauma is not completely understood. Endoplasmic reticulum (ER) stress has been shown to contribute to injury expansion and behavioral deficits in adult rodents and furthermore has been seen in adult postmortem human brains diagnosed with chronic traumatic encephalopathy. Whether endoplasmic reticulum stress is increased in juveniles with traumatic brain injury (TBI) is poorly delineated. We investigated this important topic using a juvenile rat controlled cortical impact (CCI) model. We proposed that ER stress would be significantly increased in juvenile rats following TBI and that this would correlate with behavioral deficits using a juvenile rat model. A juvenile rat (postnatal day 28) CCI model was used. Binding immunoglobulin protein (BiP) and C/EBP homologous protein (CHOP) were measured at 4 h in the ipsilateral pericontusion cortex. Hypoxia-inducible factor (HIF)-1α was measured at 48 h and tau kinase measured at 1 week and 30 days. At 4 h following injury, BiP and CHOP (markers of ER stress) were significantly elevated in rats exposed to TBI. We also found that HIF-1α was significantly upregulated 48 h following TBI showing delayed hypoxia. The early ER stress activation was additionally asso­ciated with the activation of a known tau kinase, glycogen synthase kinase-3β (GSK-3β), by 1 week. Tau oligomers measured by R23 were significantly increased by 30 days following TBI. The biochemical changes following TBI were associated with increased impulsive-like or anti-anxiety behavior measured with the elevated plus maze, deficits in short-term memory measured with novel object recognition, and deficits in spatial memory measured with the Morris water maze in juvenile rats exposed to TBI. These results show that ER stress was increased early in juvenile rats exposed to TBI, that these rats developed tau oligomers over the course of 30 days, and that they had significant short-term and spatial memory deficits following injury.


2018 ◽  
Vol 46 (1) ◽  
pp. 107-117 ◽  
Author(s):  
Ting-Ting Xu ◽  
Yang Zhang ◽  
Jia-Yang He ◽  
Dan Luo ◽  
Yi Luo ◽  
...  

Background/Aims: Alzheimer disease (AD) is a common neurodegenerative disease that is characterized by the deposition of beta-amyloid peptide and formation of intracellular neurofibrillary tangles. Due to the failure of various clinical trials of novel drugs for AD, effective drugs for AD treatment are urgently required. Methods: In this study, we used the classic APP/PS1 mouse model to explore the neuroprotective effects of a new compound, bajijiasu, and the mechanisms involved. Behavioral tests and western blotting were performed to assess the beneficial effects of bajijiasu in APP/PS1 mice. Results: Morris water maze and Y-maze test results showed that oral administration of bajijiasu (35 mg/kg/day and 70 mg/kg/day) improved learning and memory abilities in APP/PS1 mice. Bajijiasu reduced ROS and MDA levels in both the hippocampus and cortex. Moreover, western blotting results showed that bajijiasu protected neurons from apoptosis, elevated the expression levels of neurotrophic factors, and alleviated endoplasmic reticulum stress in both the hippocampus and cortex. Conclusion: These results indicate that the mechanisms underlying the effects of bajijiasu on AD might be related to beta-amyloid-downstream pathologies, particularly endoplasmic reticulum stress.


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