Chemical Chaperone PBA Attenuates ER Stress and Upregulates SOCS3 Expression as a Regulator of Leptin Signaling

Osteoarthritis (OA) is considered one of the most common arthritic diseases characterized by progressive degradation and abnormal remodeling of articular cartilage. Potential therapeutics for OA aim at restoring proper chondrocyte functioning and inhibiting apoptosis. Previous studies have demonstrated that tauroursodeoxycholic acid (TUDCA) showed anti-inflammatory and anti-apoptotic activity in many models of various diseases, acting mainly via alleviation of endoplasmic reticulum (ER) stress. However, little is known about cytoprotective effects of TUDCA on chondrocyte cells. The present study was designed to evaluate potential effects of TUDCA on interleukin-1β (IL-1β) and tunicamycin (TNC)-stimulated NHAC-kn chondrocytes cultured in normoxic and hypoxic conditions. Our results showed that TUDCA alleviated ER stress in TNC-treated chondrocytes, as demonstrated by reduced CHOP expression; however, it was not effective enough to prevent apoptosis of NHAC-kn cells in either normoxia nor hypoxia. However, co-treatment with TUDCA alleviated inflammatory response induced by IL-1β, as shown by down regulation of Il-1β, Il-6, Il-8 and Cox2, and increased the expression of antioxidant enzyme Sod2. Additionally, TUDCA enhanced Col IIα expression in IL-1β- and TNC-stimulated cells, but only in normoxic conditions. Altogether, these results suggest that although TUDCA may display chondoprotective potential in ER-stressed cells, further analyses are still necessary to fully confirm its possible recommendation as potential candidate in OA therapy.

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

Journal of Molecular Endocrinology ◽

10.1530/jme-17-0056 ◽

2017 ◽

Vol 59 (1) ◽

pp. 81-92 ◽

Cited By ~ 7

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.

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

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00405.2016 ◽

2017 ◽

Vol 312 (5) ◽

pp. L586-L598 ◽

Cited By ~ 38

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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ER stress-mediated BK dysfunction in the DRG underlies pain in a model of multiple sclerosis

10.1101/2020.01.22.915546 ◽

2020 ◽

Author(s):

Muhammad Saad Yousuf ◽

Samira Samtleben ◽

Shawn M. Lamothe ◽

Timothy Friedman ◽

Ana Catuneanu ◽

...

Keyword(s):

Multiple Sclerosis ◽

Er Stress ◽

Treatment Options ◽

Inflammatory Cells ◽

Bk Channels ◽

Resting Membrane Potential ◽

Common Symptom ◽

Chemical Chaperone ◽

Pain Hypersensitivity

ABSTRACTNeuropathic pain is a common symptom of multiple sclerosis (MS) and current treatment options are ineffective. In this study, we investigated whether endoplasmic reticulum (ER) stress in dorsal root ganglia (DRG) contributes to pain hypersensitivity in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Inflammatory cells and increased levels of ER stress markers are evident in post-mortem DRGs from MS patients. Similarly, we observed ER stress in the DRG of mice with EAE and relieving ER stress with a chemical chaperone, 4-phenylbutyric acid (4-PBA), reduced pain hypersensitivity. In vitro, 4-PBA and the selective PERK inhibitor, AMG44, normalize cytosolic Ca2+ transients in putative DRG nociceptors. We went to assess disease-mediated changes in the functional properties of Ca2+-sensitive BK-type K+ channels in DRG neurons. We found that the conductance-voltage (GV) relationship of BK channels was shifted to a more positive voltage, together with a more depolarized resting membrane potential in EAE cells. Our results suggest that ER stress in sensory neurons of MS patients and mice with EAE is a source of pain and that ER stress modulators can effectively counteract this phenotype.

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Bile Acids and Deregulated Cholangiocyte Autophagy in Primary Biliary Cholangitis

Digestive Diseases ◽

10.1159/000450913 ◽

2017 ◽

Vol 35 (3) ◽

pp. 210-216 ◽

Cited By ~ 9

Author(s):

Motoko Sasaki ◽

Yasuni Nakanuma

Keyword(s):

Bile Duct ◽

Er Stress ◽

Bile Acids ◽

Cellular Senescence ◽

Primary Biliary Cholangitis ◽

Biliary Cirrhosis ◽

Chemical Chaperone ◽

Abnormal Expression ◽

Bile Duct Lesions ◽

Mitochondrial Antigens

Background: Primary biliary cholangitis (PBC) is characterized by a high prevalence of serum anti-mitochondrial antibodies against the E2 subunit of the pyruvate dehydrogenase complex and bile duct lesions called chronic non-suppurative destructive cholangitis (CNSDC) in small bile ducts, eventually followed by extensive bile duct loss and biliary cirrhosis. Macroautophagy (a major type of autophagy) is a process of cellular self-digestion that plays a critical role in energy homeostasis and in the cytoprotection to various stresses. Deregulated autophagy is thought to be associated with various human diseases. Key Messages: Accumulating evidences suggest that deregulated autophagy may be a central player in the pathogenesis of PBC. Damaged cholangiocytes involved in CNSDC show vesicular expression of autophagy marker LC3 and accumulation of p62/sequestosome-1, suggesting deregulated autophagy. Deregulated autophagy may be involved in the autoimmune process via the abnormal expression of mitochondrial antigens and also in cholangiocyte senescence in bile duct lesions in PBC. In vitro study showed that hydrophobic bile acids, such as glycochenodeoxycholic acid (GCDC), as well as serum deprivation and oxidative stress, cause autophagy, deregulated autophagy and abnormal expression of mitochondrial antigens followed by cellular senescence in cholangiocytes. Although exact mechanisms of deregulated autophagy remain to be clarified, endoplasmic reticulum (ER) stress may be a plausible cause of deregulated autophagy induced by GCDC in cholangiocytes. Impaired ‘biliary bicarbonate umbrella' may further exacerbate the toxicity of GCDC to cholangiocytes. Interestingly, pretreatment with ursodeoxycholic acid (UDCA) and tauro-UDCA, which is a chemical chaperone enhancing the adaptive capacity of the ER, significantly suppressed ER stress, deregulated autophagy and cellular senescence induced by GCDC and other stresses in cholangiocytes. Conclusions: GCDC may play a role in the occurrence of deregulated autophagy and cellular senescence at least partly through the induction of ER stress in PBC. Deregulated autophagy and cellular senescence can be a promising therapeutic target in PBC.

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The unfolded protein response controls ER stress-induced apoptosis of lung epithelial cells through angiotensin generation

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00449.2015 ◽

2016 ◽

Vol 311 (5) ◽

pp. L846-L854 ◽

Cited By ~ 15

Author(s):

Hang Nguyen ◽

Bruce D. Uhal

Keyword(s):

Epithelial Cells ◽

Er Stress ◽

Unfolded Protein Response ◽

Cathepsin D ◽

Lung Epithelial Cells ◽

Chemical Chaperone ◽

Unfolded Protein ◽

Induced Apoptosis ◽

The Unfolded Protein Response ◽

Protein Response

Recent work from this laboratory showed that endoplasmic reticulum (ER) stress-induced apoptosis of alveolar epithelial cells (AECs) is regulated by the autocrine angiotensin (ANG)II/ANG1-7 system. The proteasome inhibitor MG132 or surfactant protein C (SP-C) BRICHOS domain mutation G100S induced apoptosis in human AECs by activating the proapoptotic cathepsin D and reducing antiapoptotic angiotensin converting enzyme-2 (ACE-2). This study tested the hypothesis that ER stress-induced apoptosis of human AECs might be mediated by influence of the unfolded protein response (UPR) on the autocrine ANGII/ANG1-7 system. A549 cells were challenged with MG132 or SP-C BRICHOS domain mutant G100S to induce ER stress and activation of UPR pathways. The results showed that either MG132 or G100S SP-C mutation activated all three canonical pathways of the UPR (IRE1/XBP1, ATF6, and PERK/eIF2α), which led to a significant increase in cathepsin D or in TACE (an ACE-2 ectodomain shedding enzyme) and eventually caused AEC apoptosis. However, ER stress-induced AEC apoptosis could be prevented by chemical chaperone or by UPR blockers. It is also suggested that ATF6 and IRE1 pathways might play important role in regulation of angiotensin system. These data demonstrate that ER stress induces apoptosis in human AECs through mediation of UPR pathways, which in turn regulate the autocrine ANGII/ANG1-7 system. They also demonstrated that ER stress-induced AEC apoptosis can be blocked by inhibition of UPR signaling pathways.

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Proteomic profile of 4-PBA treated human neuronal cells during ER stress

Molecular Omics ◽

10.1039/c7mo00114b ◽

2018 ◽

Vol 14 (1) ◽

pp. 53-63 ◽

Cited By ~ 10

Author(s):

Bhavneet Kaur ◽

Ajay Bhat ◽

Rahul Chakraborty ◽

Khushboo Adlakha ◽

Shantanu Sengupta ◽

...

Keyword(s):

Er Stress ◽

Neuronal Cells ◽

Proteomic Profile ◽

Chemical Chaperone ◽

Human Neuronal Cells

Global proteomics supports the role of 4-PBA as a chemical chaperone in alleviating neurotoxicity during ER stress.

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Reduction of ER stress via a chemical chaperone prevents disease phenotypes in a mouse model of primary open angle glaucoma

Journal of Clinical Investigation ◽

10.1172/jci58183 ◽

2011 ◽

Vol 121 (9) ◽

pp. 3542-3553 ◽

Cited By ~ 149

Author(s):

Gulab S. Zode ◽

Markus H. Kuehn ◽

Darryl Y. Nishimura ◽

Charles C. Searby ◽

Kabhilan Mohan ◽

...

Keyword(s):

Mouse Model ◽

Er Stress ◽

Primary Open Angle Glaucoma ◽

Open Angle Glaucoma ◽

Open Angle ◽

Chemical Chaperone ◽

Disease Phenotypes

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Effects of Jasmonic Acid in ER Stress and Unfolded Protein Response in Tomato Plants

Biomolecules ◽

10.3390/biom10071031 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1031

Author(s):

Zalán Czékus ◽

Orsolya Csíkos ◽

Attila Ördög ◽

Irma Tari ◽

Péter Poór

Keyword(s):

Jasmonic Acid ◽

Er Stress ◽

Unfolded Protein Response ◽

Transcript Accumulation ◽

Chemical Chaperone ◽

Tomato Plants ◽

Transcript Levels ◽

Unfolded Protein ◽

Protein Response

Endoplasmic reticulum (ER) stress elicits a protective mechanism called unfolded protein response (UPR) to maintain cellular homeostasis, which can be regulated by defence hormones. In this study, the physiological role of jasmonic acid (JA) in ER stress and UPR signalling has been investigated in intact leaves of tomato plants. Exogenous JA treatments not only induced the transcript accumulation of UPR marker gene SlBiP but also elevated transcript levels of SlIRE1 and SlbZIP60. By the application of JA signalling mutant jai1 plants, the role of JA in ER stress sensing and signalling was further investigated. Treatment with tunicamycin (Tm), the inhibitor of N-glycosylation of secreted glycoproteins, increased the transcript levels of SlBiP. Interestingly, SlIRE1a and SlIRE1b were significantly lower in jai1. In contrast, the transcript accumulation of Bax Inhibitor-1 (SlBI1) and SlbZIP60 was higher in jai1. To evaluate how a chemical chaperone modulates Tm-induced ER stress, plants were treated with sodium 4-phenylbutyrate, which also decreased the Tm-induced increase in SlBiP, SlIRE1a, and SlBI1 transcripts. In addition, it was found that changes in hydrogen peroxide content, proteasomal activity, and lipid peroxidation induced by Tm is regulated by JA, while nitric oxide was not involved in ER stress and UPR signalling in leaves of tomato.

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Obesity-Linked Variants of Melanocortin-4 Receptor Are Misfolded in the Endoplasmic Reticulum and Can Be Rescued to the Cell Surface by a Chemical Chaperone

Endocrine Reviews ◽

10.1210/edrv.31.4.9985 ◽

2010 ◽

Vol 31 (4) ◽

pp. 605-605

Author(s):

Susana Granell ◽

Sameer Mohammad ◽

Ramanagouda Ramanagoudr-Bhojappa ◽

Giulia Baldini

Keyword(s):

Endoplasmic Reticulum ◽

Cell Surface ◽

Er Stress ◽

Binding Protein ◽

Intracellular Localization ◽

Specific Inhibitor ◽

Surface Expression ◽

Cell Surface Expression ◽

Chemical Chaperone ◽

Melanocortin 4 Receptor

Abstract Melanocortin-4 receptor (MC4R) is a G protein-coupled receptor expressed in the brain where it controls food intake. Many obesity-linked MC4R variants are poorly expressed at the plasma membrane and are retained intracellularly. We have studied the intracellular localization of four obesity-linked MC4R variants, P78L, R165W, I316S, and I317T, in immortalized neurons. We find that these variants are all retained in the endoplasmic reticulum (ER), are ubiquitinated to a greater extent than the wild-type (wt) receptor, and induce ER stress with increased levels of ER chaperones as compared with wt-MC4R and appearance of CCAAT/enhancer-binding protein homologous protein. Expression of the X-box-binding-protein-1 with selective activation of a protective branch of the unfolded protein response did not have any effect on the cell surface expression of MC4R-I316S. Conversely, the pharmacological chaperone 4-phenyl butyric acid (PBA) increased the cell surface expression of wt-MC4R, MC4R-I316S, and I317T by more than 40%. PBA decreased ubiquitination of MC4R-I316S and prevented ER stress induced by expression of the mutant, suggesting that the drug functions to promote MC4R folding. MC4R-I316S rescued to the cell surface is functional, with a 52% increase in agonist-induced cAMP production, as compared with untreated cells. Also direct inhibition of wt-MC4R and MC4R-I316S ubiquitination by a specific inhibitor of the ubiquitin-activating enzyme 1 increased by approximately 40% the expression of the receptors at the cell surface, and the effects of PBA and ubiquitin-activating enzyme 1 were additive. These data offer a cell-based rationale that drugs that improve MC4R folding or decrease ER-associated degradation of the receptor may function to treat some forms of hereditary obesity.

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