scholarly journals Endoplasmic reticulum stress in the peripheral nervous system is a significant driver of neuropathic pain

2015 ◽  
Vol 112 (29) ◽  
pp. 9082-9087 ◽  
Author(s):  
Bora Inceoglu ◽  
Ahmed Bettaieb ◽  
Carlos A. Trindade da Silva ◽  
Kin Sing Stephen Lee ◽  
Fawaz G. Haj ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Nervous System ◽  
Neuropathic Pain ◽  
Er Stress ◽  
Peripheral Nervous System ◽  
Pain Behavior ◽  
Type I ◽  
Chemical Chaperone ◽  
Chemical Inducers

Despite intensive effort and resulting gains in understanding the mechanisms underlying neuropathic pain, limited success in therapeutic approaches have been attained. A recently identified, nonchannel, nonneurotransmitter therapeutic target for pain is the enzyme soluble epoxide hydrolase (sEH). The sEH degrades natural analgesic lipid mediators, epoxy fatty acids (EpFAs), therefore its inhibition stabilizes these bioactive mediators. Here we demonstrate the effects of EpFAs on diabetes induced neuropathic pain and define a previously unknown mechanism of pain, regulated by endoplasmic reticulum (ER) stress. The activation of ER stress is first quantified in the peripheral nervous system of type I diabetic rats. We demonstrate that both pain and markers of ER stress are reversed by a chemical chaperone. Next, we identify the EpFAs as upstream modulators of ER stress pathways. Chemical inducers of ER stress invariably lead to pain behavior that is reversed by a chemical chaperone and an inhibitor of sEH. The rapid occurrence of pain behavior with inducers, equally rapid reversal by blockers and natural incidence of ER stress in diabetic peripheral nervous system (PNS) argue for a major role of the ER stress pathways in regulating the excitability of the nociceptive system. Understanding the role of ER stress in generation and maintenance of pain opens routes to exploit this system for therapeutic purposes.

Abstract 083: Role of Endoplasmic Reticulum Stress in the Subfornical Organ (SFO) in Fluid Balance and Metabolic Effects of Brain Renin-Angiotensin System (RAS) Activation

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Fusakazu Jo ◽  
Hiromi Jo ◽  
Aline M Hilzendeger ◽  
Martin D Cassell ◽  
D. T Rutkowski ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Water Intake ◽  
Fluid Balance ◽  
Functional Role ◽  
Metabolic Effects ◽  
Chemical Chaperone ◽  
Reduced Drinking ◽  
The Brain

Endoplasmic reticulum (ER) stress has been identified as an important contributor to neurological diseases and implicated in mediating hypothalamic inflammation and the hypertensive effects of angiotensin II (AngII). We examined the role of ER stress in the metabolic and fluid balance effects of brain AngII in two mouse models: 1) sRA transgenic mice (expressing human renin in neurons and human angiotensinogen in glia and neurons), 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 (RMR). CCAAT-enhancer-binding protein homologous protein (CHOP), a marker of chronic ER stress, was examined by immunocytochemistry in the brain of both models. CHOP immunoreactivity was evident in the SFO of sRA and DOCA-salt mice but was absent in control and CHOP-/- mice. 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 RMR observed in both models. In initial studies, ICV TUDCA significantly attenuated the polydipsia (aCSF 20.7±0.9 vs TUDCA 10.8±1.0 mL/day, n=6,2) and RMR (aCSF, 3.38±0.07 vs TUDCA 3.16±0.06 mL O2/100g/min, P<0.05 n=13,11) in the DOCA-salt model. ICV TUDCA had similar effects on the polydipsia in the sRA model (51±10% of aCSF control, P<0.05 n=3,4). In the DOCA-salt model, daily ICV injections of TUDCA (10 days, 5ug/ul) markedly reduced drinking, but polydipsia returned one day after the injections were terminated (n=14,12). Daily ICV injection of another ER stress reducer 4-phenylbutyrate (5ug/ul) also reduced drinking (P<0.05 n=5,4). To assess the functional role of CHOP, we measured RMR and water intake in CHOP-/- mice. Interestingly, CHOP-/- mice exhibited increased baseline RMR (CHOP-/- 0.161±0.010 vs C57 0.140±0.005 kcal/hr, P<0.05 n=10,9). The increase in water intake in response to DOCA-salt was blunted (32.7±0.5 vs 22.8±1.1 ml/day, P<0.05, n=4,5) in CHOP-/- mice. Together these data mechanistically implicate ER stress in the fluid and metabolic responses to increased brain RAS activity and suggest CHOP may play a functional role.

scholarly journals Fibronectin Overexpression Modulates Formation of Macrophage Foam Cells by Activating SREBP2 Involved in Endoplasmic Reticulum Stress

2015 ◽  
Vol 36 (5) ◽  
pp. 1821-1834 ◽  
Author(s):  
Hansong Du ◽  
Yu Wang ◽  
Zhengfeng Zhang ◽  
Jing Yang ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Lipid Accumulation ◽  
Foam Cell ◽  
Regulatory Element ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Direct Role ◽  
Chemical Chaperone

Aims: To explore the explicit role of fibronectin (FN) isforms in atherosclerotic lesions and the underlying mechanisms. Methods and Results: Inducible stable expression was performed, and similar results were observed between EDA+FN (FN containing EDA domain) and EDA-FN (FN devoid of EDA domain). FN isforms could trigger endoplasmic reticulum (ER) stress, thereby leading to lipid accumulation in cultured Raw264.7 cells. FN isforms-induced gene expression and lipid accumulation were inhibited by a chemical chaperone 4-phenyl butyric acid (PBA) or by overexpression of the ER chaperone, GRP78/BiP, demonstrating a direct role of ER stress in activation of cholesterol/triglyceride biosynthesis. Moreover, activation of the sterol regulatory element binding protein-2 (SREBP2) was found to be downstream of ER stress, and this activation was affirmed to account for the intracellular accumulation of cholesterol using RNAi technique. Conclusion: our study suggests that enhanced FN in lesions facilitates foam cell formation due to dysregulation of the endogenous sterol response pathway by activation of ER stress, and confirms that EDA+FN has no more pro-atherogenic role than EDA-FN in triggering ER stress.

Abstract 176: Role of Endoplasmic Reticulum Stress in the SFO in Fluid Balance and Metabolic Effects of Brain Renin-Angiotensin System Activation

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Fusakazu Jo ◽  
Hiromi Jo ◽  
Aline M Hilzendeger ◽  
Martin D Cassell ◽  
D. T Rutkowski ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Metabolic Rate ◽  
Er Stress ◽  
Fluid Balance ◽  
Neurological Diseases ◽  
Resting Metabolic Rate ◽  
Metabolic Effects ◽  
Chemical Chaperone ◽  
The Brain

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.

c-Jun Inhibits Thapsigargin-Induced ER Stress Through Up-Regulation of DSCR1/Adapt78

2008 ◽  
Vol 233 (10) ◽  
pp. 1289-1300 ◽  
Author(s):  
Peng Zhao ◽  
Xiaoyan Xiao ◽  
Agnes S. Kim ◽  
M. Fatima Leite ◽  
Jinxia Xu ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Wild Type Mouse ◽  
Mouse Fibroblast ◽  
Expression Levels ◽  
Mouse Fibroblasts ◽  
The Unfolded Protein Response ◽  
Calcineurin Activity

The endoplasmic reticulum (ER) is exquisitely sensitive to changes in its internal environment. Various conditions, collectively termed “ER stress”, can perturb ER function, leading to the activation of a complex response known as the unfolded protein response (UPR). Although c-Jun N-terminal kinase (JNK) activation is nearly always associated with cell death by various stimuli, the functional role of JNK in ER stress-induced cell death remains unclear. JNK regulates gene expression through the phosphorylation and activation of transcription factors, such as c-Jun. Here, we investigated the role of c-Jun in the regulation of ER stress-related genes. c-Jun expression levels determined the response of mouse fibroblasts to ER stress induced by thapsigargin (TG, an inhibitor of sarco/endoplasmic reticulum Ca2+ ATPase). c-jun−/− mouse fibroblast cells were more sensitive to TG-induced cell death compared to wild-type mouse fibroblasts, while reconstitution of c-Jun expression in c-jun−/− cells (c-Jun Re) enhanced resistance to TG-induced cell death. The expression levels of ER chaperones Grp78 and Gadd153 induced by TG were lower in c-Jun Re than in c-jun−/− cells. Moreover, TG treatment significantly increased calcineurin activity in c-jun−/− cells, but not in c-Jun Re cells. In c-Jun Re cells, TG induced the expression of Adapt78, also known as the Down syndrome critical region 1 (DSCR1), which is known to block calcineurin activity. Taken together, our findings suggest that c-Jun, a transcription factor downstream of the JNK signaling pathway, up-regulates Adapt78 expression in response to TG-induced ER stress and contributes to protection against TG-induced cell death.

scholarly journals Maternal high-fat diet induces metabolic stress response disorders in offspring hypothalamus

2017 ◽  
Vol 59 (1) ◽  
pp. 81-92 ◽  
Author(s):  
Long The Nguyen ◽  
Sonia Saad ◽  
Yi Tan ◽  
Carol Pollock ◽  
Hui Chen
Keyword(s):  
Endoplasmic Reticulum ◽  
Body Weight ◽  
Er Stress ◽  
High Fat Diet ◽  
Maternal Obesity ◽  
Mrna Level ◽  
Metabolic Stress ◽  
High Fat ◽  
Chemical Chaperone ◽  
Protein Levels

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.

scholarly journals Attenuation of endoplasmic reticulum stress by caffeine ameliorates hyperoxia-induced lung injury

2017 ◽  
Vol 312 (5) ◽  
pp. L586-L598 ◽  
Author(s):  
Ru-Jeng Teng ◽  
Xigang Jing ◽  
Teresa Michalkiewicz ◽  
Adeleye J. Afolayan ◽  
Tzong-Jin Wu ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Lung Injury ◽  
Er Stress ◽  
Saline Control ◽  
Sprague Dawley ◽  
Chemical Chaperone ◽  
Stress Markers ◽  
Rat Pups ◽  
Caffeine Treatment ◽  
Downstream Effectors

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.

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