Activation of NF-kappa B by ER stress requires both Ca2+ and reactive oxygen intermediates as messengers

Ribosomal proteins: the missing piece in the inflammation puzzle?

Ribosomal proteins (RPs) are constituents of macromolecular machinery, ribosome that translates genetic information into proteins. Besides ribosomal functions, RPs are now getting appreciated for their 'moonlighting'/extra-ribosomal functions modulating many cellular processes. Accumulating evidence suggests that a number of RPs are involved in inflammation. Though acute inflammation is a part of the innate immune response, uncontrolled inflammation is a driving factor for several chronic inflammatory diseases. An in-depth understanding of inflammation regulation has always been valued for the better management of associated diseases. Hence, this review first outlines the common livelihood of RPs and then provides a comprehensive account of five RPs that significantly contribute to the inflammation process. Finally, we discuss the possible therapeutic uses of RPs against chronic inflammatory diseases.

Modulation of endoplasmic reticulum stress response pathways by respiratory viruses

Acute respiratory infections (ARIs) are amongst the leading causes of death and disability, and the greatest burden of disease impacts children, pregnant women, and the elderly. Respiratory viruses account for the majority of ARIs. The unfolded protein response (UPR) is a host homeostatic defence mechanism primarily activated in response to aberrant endoplasmic reticulum (ER) resident protein accumulation in cell stresses including viral infection. The UPR has been implicated in the pathogenesis of several respiratory diseases, as the respiratory system is particularly vulnerable to chronic and acute activation of the ER stress response pathway. Many respiratory viruses therefore employ strategies to modulate the UPR during infection, with varying effects on the host and the pathogens. Here, we review the specific means by which respiratory viruses affect the host UPR, particularly in association with the high production of viral glycoproteins, and the impact of UPR activation and subversion on viral replication and disease pathogenesis. We further review the activation of UPR in common co-morbidities of ARIs and discuss the therapeutic potential of modulating the UPR in virally induced respiratory diseases.

Mediation of endoplasmic reticulum stress and NF-κB signaling pathway in DINP-exacerbated allergic asthma: A toxicological study with Balb/c mice

Epidemiological evidence indicates a significant relationship between exposure to diisononyl phthalate and allergic asthma. Despite this, the mechanism underlying this association remains unclear. Previous toxicological researches have suggested that the development of allergic asthma may involve the activation of endoplasmic reticulum stress (ERS) and the nuclear factor κ-B (NF-κB) pathways. Nevertheless, it is currently unknown whether these specific signaling pathways are implicated in diisononyl phthalate (DINP)-induced allergic asthma. The objective of this research was to understand how DINP exacerbates allergic asthma in Balb/c mice through ERS and NF-κB pathways. To systematically examine the aggravated effects of DINP in Balb/c mice, we measured airway hyperresponsiveness (AHR), lung tissue pathology, cytokines, and ERS and NF-κB pathway biomarkers. Additionally, we applied the ERS antagonist phenylbutyric acid (4-PBA) or the NF-κB antagonist pyrrolidine dithiocarbamate (PDTC) to verify the mediating effects of ERS and NF-κB on DINP-exacerbated allergic asthma. The results of our experiment show that oral DINP exposure may exacerbate airway hyperresponsiveness and airway remodeling. This deterioration is accompanied by an imbalance in immunoglobulin levels, Th17/Treg cells, ERS, and NF-κB biomarkers, leading to the activation of pro-inflammatory pathways. Furthermore, our study found that the blocking effect of 4-PBA or PDTC can inhibit the Th17/Treg imbalance and effectively alleviate symptoms resembling allergic asthma. In conclusion, ERS and NF-κB signaling pathways play an important role in regulating DINP-induced allergic asthma exacerbations.

Cross-talk between bioactive lipid mediators and the unfolded protein response in ischemic stroke

Ischemic cerebral stroke is a severe medical condition that affects about 15 million people every year and is the second leading cause of death and disability globally. Ischemic stroke results in neuronal cell death and neurological impairment. Current therapies may not adequately address the deleterious metabolic changes and may increase neurological damage. Oxygen and nutrient depletion along with the tissue damage result in endoplasmic reticulum (ER) stress, including the Unfolded Protein Response (UPR), and neuroinflammation in the affected area and cause cell death in the lesion core. The spatio-temporal production of lipid mediators, either pro-inflammatory or pro-resolving, decides the course and outcome of stroke. The modulation of the UPR as well as the resolution of inflammation promotes post-stroke cellular viability and neuroprotection. However, studies about the interplay between the UPR and bioactive lipid mediators remain elusive and this review gives insights about the crosstalk between lipid mediators and the UPR in ischemic stroke. Overall, the treatment of ischemic stroke is often inadequate due to lack of effective drugs, thus, this review will provide novel therapeutical strategies that could promote the functional recovery from ischemic stroke.

Cardiomyocyte-Targeting Peptide to Deliver Amiodarone

BACKGROUND

Amiodarone is underutilized due to significant off-target toxicities. We hypothesized that targeted delivery to the heart would lead to the lowering of the dose by utilizing a cardiomyocyte-targeting peptide (CTP), a cell-penetrating peptide identified by our prior phage display work.

METHODS

CTP was synthesized thiolated at the N-terminus, conjugated to amiodarone via Schiff base chemistry, HPLC purified, and confirmed with MALDI/TOF. The stability of the conjugate was assessed using serial HPLCs. Guinea pigs (GP) were injected intraperitoneally daily with vehicle (7 days), amiodarone (7 days; 80 mg/kg), CTP-amiodarone (5 days; 26.3 mg/kg), or CTP (5 days; 17.8 mg/kg), after which the GPs were euthanized, and the hearts were excised and perfused on a Langendorff apparatus with Tyrode's solution and blebbistatin (5 µM) to minimize the contractions. Voltage (RH237) and Ca2+-indicator dye (Rhod-2/AM) were injected, and fluorescence from the epicardium split and was captured by two cameras at 570-595 nm for the cytosolic Ca2+ and 610-750 nm wavelengths for the voltage. Subsequently, the hearts were paced at 250 ms with programmed stimulation to measure the changes in the conduction velocities (CV), action potential duration (APD), and Ca2+ transient durations at 90% recovery (CaTD90). mRNA was extracted from all hearts, and RNA sequencing was performed with results compared to the control hearts.

RESULTS

The CTP-amiodarone remained stable for up to 21 days at 37 °C. At ~1/15th of the dose of amiodarone, the CTP-amiodarone decreased the CV in hearts significantly compared to the control GPs (0.92 ± 0.05 vs. 1.00 ± 0.03 ms, p = 0.0007), equivalent to amiodarone alone (0.87 ± 0.08 ms, p = 0.0003). Amiodarone increased the APD (192 ± 5 ms vs. 175 ± 8 ms for vehicle, p = 0.0025), while CTP-amiodarone decreased it significantly (157 ± 16 ms, p = 0.0136), similar to CTP alone (155 ± 13 ms, p = 0.0039). Both amiodarone and CTP-amiodarone significantly decreased the calcium transients compared to the controls. CTP-amiodarone and CTP decreased the CaTD90 to an extent greater than amiodarone alone (p < 0.001). RNA-seq showed that CTP alone increased the expression of DHPR and SERCA2a, while it decreased the expression of the proinflammatory genes, NF-kappa B, TNF-α, IL-1β, and IL-6.

CONCLUSIONS

Our data suggest that CTP can deliver amiodarone to cardiomyocytes at ~1/15th the total molar dose of the amiodarone needed to produce a comparable slowing of CVs. The ability of CTP to decrease the AP durations and CaTD90 may be related to its increase in the expression of Ca-handling genes, which merits further study.

Cardiomyocyte Targeting Peptide to Deliver Amiodarone

Background

Amiodarone is underutilized due to significant off-target toxicities. We hypothesized that targeted delivery to the heart would lead to lowering of dose by utilizing a cardiomyocyte targeting peptide (CTP), a cell penetrating peptide identified by our prior phage display work.

Methods

CTP was synthesized thiolated at the N-terminus, conjugated to amiodarone via Schiff base chemistry, HPLC purified and confirmed with MALDI/TOF. Stability of the conjugate was assessed using serial HPLCs. Guinea pigs (GP) were injected intraperitoneally daily with vehicle (7 days), amiodarone (7 days; 80mg/Kg), CTP-amiodarone (5 days;26.3mg/Kg), or CTP (5 days; 17.8mg/Kg), after which GPs were euthanized, hearts excised, perfused on a Langendorff apparatus with Tyrode's solution and blebbistatin (5μM) to minimize contractions. Voltage (RH237) and Ca 2+ -indicator dye (Rhod-2/AM) were injected, fluorescence from the epicardium split and focused on two cameras capturing at 570-595nm for cytosolic Ca 2+ and 610-750nm wavelengths for voltage. Subsequently, hearts were paced at 250ms with programmed stimulation to measure changes in conduction velocities (CV), action potential duration (APD) and Ca 2+ transient durations at 90% recovery (CaTD 90 ). mRNA was extracted from all hearts and RNA sequencing performed with results compared to control hearts.

Results

CTP-amiodarone remained stable for up to 21 days at 37°C. At ∼1/15 th of the dose of amiodarone, CTP-amiodarone decreased CV in hearts significantly compared to control GPs (0.92±0.05 vs. 1.00±0.03m/s, p=0.0007), equivalent to amiodarone alone (0.87±0.08ms, p=0.0003). Amiodarone increased APD (192±5ms vs. 175±8ms for vehicle, p=0.0025), while CTP-amiodarone decreased it significantly (157±16ms, p=0.0136) similar to CTP alone (155±13ms, p=0.0039). Both amiodarone and CTP-amiodarone significantly decreased calcium transients compared to controls. CTP-amiodarone and CTP decreased CaTD 90 to an extent greater than amiodarone alone (p<0.001). RNA-seq showed that CTP alone increased the expression of DHPR and SERCA2a, while decreasing expression of proinflammatory genes NF-kappa B, TNF-α, IL-1β, and IL-6.

Conclusions

Our data suggests that CTP can deliver amiodarone to cardiomyocytes at ∼1/15 th the total molar dose of amiodarone needed to produce comparable slowing of CVs. The ability of CTP to decrease AP durations and CaTD 90 may be related to its increase in expression of Ca-handling genes, and merits further study.

Calcium Ions Aggravate Alzheimer's Disease Through the Aberrant Activation of Neuronal Networks, Leading to Synaptic and Cognitive Deficits

Alzheimer’s disease (AD) is a neurodegenerative disease that is characterized by the production and deposition of β-amyloid protein (Aβ) and hyperphosphorylated tau, leading to the formation of β-amyloid plaques (APs) and neurofibrillary tangles (NFTs). Although calcium ions (Ca²⁺) promote the formation of APs and NFTs, no systematic review of the mechanisms by which Ca²⁺ affects the development and progression of AD has been published. Therefore, the current review aimed to fill the gaps between elevated Ca²⁺ levels and the pathogenesis of AD. Specifically, we mainly focus on the molecular mechanisms by which Ca²⁺ affects the neuronal networks of neuroinflammation, neuronal injury, neurogenesis, neurotoxicity, neuroprotection, and autophagy. Furthermore, the roles of Ca²⁺ transporters located in the cell membrane, endoplasmic reticulum (ER), mitochondria and lysosome in mediating the effects of Ca²⁺ on activating neuronal networks that ultimately contribute to the development and progression of AD are discussed. Finally, the drug candidates derived from herbs used as food or seasoning in Chinese daily life are summarized to provide a theoretical basis for improving the clinical treatment of AD.

Bifidobacterium dentium-derived y-glutamylcysteine suppresses ER-mediated goblet cell stress and reduces TNBS-driven colonic inflammation

Endoplasmic reticulum (ER) stress compromises the secretion of MUC2 from goblet cells and has been linked with inflammatory bowel disease (IBD). Although Bifidobacterium can beneficially modulate mucin production, little work has been done investigating the effects of Bifidobacterium on goblet cell ER stress. We hypothesized that secreted factors from Bifidobacterium dentium downregulate ER stress genes and modulates the unfolded protein response (UPR) to promote MUC2 secretion. We identified by mass spectrometry that B. dentium secretes the antioxidant γ-glutamylcysteine, which we speculate dampens ER stress-mediated ROS and minimizes ER stress phenotypes. B. dentium cell-free supernatant and γ-glutamylcysteine were taken up by human colonic T84 cells, increased glutathione levels, and reduced ROS generated by the ER-stressors thapsigargin and tunicamycin. Moreover, B. dentium supernatant and γ-glutamylcysteine were able to suppress NF-kB activation and IL-8 secretion. We found that B. dentium supernatant, γ-glutamylcysteine, and the positive control IL-10 attenuated the induction of UPR genes GRP78, CHOP, and sXBP1. To examine ER stress in vivo, we first examined mono-association of B. dentium in germ-free mice which increased MUC2 and IL-10 levels compared to germ-free controls. However, no changes were observed in ER stress-related genes, indicating that B. dentium can promote mucus secretion without inducing ER stress. In a TNBS-mediated ER stress model, we observed increased levels of UPR genes and pro-inflammatory cytokines in TNBS treated mice, which were reduced with addition of live B. dentium or γ-glutamylcysteine. We also observed increased colonic and serum levels of IL-10 in B. dentium- and γ-glutamylcysteine-treated mice compared to vehicle control. Immunostaining revealed retention of goblet cells and mucus secretion in both B. dentium- and γ-glutamylcysteine-treated animals. Collectively, these data demonstrate positive modulation of the UPR and MUC2 production by B. dentium-secreted compounds.

Phytochemical Composition, Anti-Inflammatory and ER Stress-Reducing Potential of Sambucus ebulus L. Fruit Extract

Sambucus ebulus L. (SE) fruits are used for their immunostimulation, hematopoietic and antiviral potential. Recently, we focused on analyzing the mechanism underlying SE fruit aqueous extract's (FAE) immunomodulation and anti-inflammatory activities, with attention to its endoplasmic reticulum (ER) stress-reducing potential. J774A.1 macrophages were treated with SE FAE alone or in conditions of lipopolysaccharides (LPS) stimulation. Using GC-MS and LC-MS/MS, its phytochemical composition was analyzed. To measure transcription and protein levels, we used qPCR and Western blot, respectively. The prevailing phytochemicals in SE FAE were hydroxycinnamic acids, proanthocyanidins and anthocyanins. The content of some amino acids, organic acids, alcohols, fatty acids and esters were newly reported. Extracts exerted an immunostimulation potential by stimulating IL-6, TNFα, Ccl2, COX2 and iNOS transcription, without inducing ER stress. SE FAE suppressed the LPS-induced transcription of inflammation related genes (IL-1β, IL-6, TNFα, Ccl2, Icam-1, Fabp4, COX2, iNOS, Noxo1, IL-1ra, Sirt-1) and reduced the protein levels of iNOS, peIF2α, ATF6α and CHOP. The effects were comparable to that of salicylic acid. SE suppresses LPS-stimulated inflammatory markers on the transcription and translation levels. Targeting ER stress is possibly another mechanism underlying its anti-inflammatory potential. These findings reveal the potential of SE fruits as a beneficial therapeutic of inflammation and ER stress-related pathological conditions.

Mechanism of Endoplasmic Reticulum Stress in Cerebral Ischemia

Endoplasmic reticulum (ER) is the main organelle for protein synthesis, trafficking and maintaining intracellular Ca²⁺ homeostasis. The stress response of ER results from the disruption of ER homeostasis in neurological disorders. Among these disorders, cerebral ischemia is a prevalent reason of death and disability in the world. ER stress stemed from ischemic injury initiates unfolded protein response (UPR) regarded as a protection mechanism. Important, disruption of Ca²⁺ homeostasis resulted from cytosolic Ca²⁺ overload and depletion of Ca²⁺ in the lumen of the ER could be a trigger of ER stress and the misfolded protein synthesis. Brain cells including neurons, glial cells and endothelial cells are involved in the complex pathophysiology of ischemic stroke. This is generally important for protein underfolding, but even more for cytosolic Ca²⁺ overload. Mild ER stress promotes cells to break away from danger signals and enter the adaptive procedure with the activation of pro-survival mechanism to rescue ischemic injury, while chronic ER stress generally serves as a detrimental role on nerve cells via triggering diverse pro-apoptotic mechanism. What’s more, the determination of some proteins in UPR during cerebral ischemia to cell fate may have two diametrically opposed results which involves in a specialized set of inflammatory and apoptotic signaling pathways. A reasonable understanding and exploration of the underlying molecular mechanism related to ER stress and cerebral ischemia is a prerequisite for a major breakthrough in stroke treatment in the future. This review focuses on recent findings of the ER stress as well as the progress research of mechanism in ischemic stroke prognosis provide a new treatment idea for recovery of cerebral ischemia.

Impact of Concomitant Aberrant CD200 and BCL2 Overexpression on Outcome of Acute Myeloid Leukemia: A Cohort Study from a Single Center

Objective:

CD200 and BCL2 overexpression is independently associated with inferior survival in acute myeloid leukemia (AML), and these two factors are frequently co-expressed; however, no data are available on the role of concomitant aberrant CD200 and BCL2 expression on outcome of AML patients. We aimed to elucidate the prognostic role of CD200/BCL2 co-expression and its association with specific leukemia subsets.

Materials and Methods:

We analyzed 242 adult AML patients uniformly treated with intensive chemotherapy, evaluating the impact of CD200 and BCL2 expression on complete remission (CR), disease-free survival, and overall survival (OS).

Results:

CD200 and BCL2 were expressed in 139 (57.4%) and 137 (56.6%) cases, respectively, with 92 patients (38%) displaying double positivity (DP), 58 (24%) displaying double negativity (DN), and 92 patients expressing only either CD200 (n=47) or BCL2 (n=45). CR was achieved in 71% of cases, being less frequent in DP patients (60%) compared to other groups (76%-81%, p<0.001). In the whole population 3-year OS was 44%, being lower in DP patients (28%) than in patients with single CD200 or BCL2 expression (47%) or DN cases (60%; p=0.004). Other factors associated with worse OS were advanced age, CD34 positivity, secondary AML, and high white blood cell count at diagnosis; combining these 4 factors with CD200/BCL2 DP, we identified 6 groups with significantly different rates of survival (3-year OS ranging from 90% to 0%).

Conclusion:

Our data support a synergistic effect of CD200 and BCL2 in AML cells, conferring an enhanced survival capacity in a permissive microenvironment and resulting in worse prognosis.

Molecular mechanisms of anthracycline cardiovascular toxicity

Anthracyclines are effective chemotherapeutic agents, commonly used in the treatment of a variety of hematologic malignancies and solid tumors. However, their use is associated with a significant risk of cardiovascular toxicities and may result in cardiomyopathy and heart failure. Cardiomyocyte toxicity occurs via multiple molecular mechanisms, including topoisomerase II-mediated DNA double-strand breaks and reactive oxygen species (ROS) formation via effects on the mitochondrial electron transport chain, NADPH oxidases (NOXs), and nitric oxide synthases (NOSs). Excess ROS may cause mitochondrial dysfunction, endoplasmic reticulum stress, calcium release, and DNA damage, which may result in cardiomyocyte dysfunction or cell death. These pathophysiologic mechanisms cause tissue-level manifestations, including characteristic histopathologic changes (myocyte vacuolization, myofibrillar loss, and cell death), atrophy and fibrosis, and organ-level manifestations including cardiac contractile dysfunction and vascular dysfunction. In addition, these mechanisms are relevant to current and emerging strategies to diagnose, prevent, and treat anthracycline-induced cardiomyopathy. This review details the established and emerging data regarding the molecular mechanisms of anthracycline-induced cardiovascular toxicity.

Effect of oxidative stress and calcium deregulation on FAM26F (CALHM6) expression during hepatitis B virus infection

Background

Family with sequence similarity 26, member F (FAM26F) is an important innate immunity modulator playing a significant role in diverse immune responses, however, the association of FAM26F expression with HBV infection is not yet known. Thus, the current study aims to explore the differential expression of FAM26F in vitro in HepAD38 and HepG2 cell lines upon HBV infection, and in vivo in HBV infected individuals. The effects of antioxidant and calcium inhibitors on the regulation of FAM26F expression were also evaluated. The expression of FAM26F was simultaneously determined with well-established HBV infection markers: IRF3, and IFN-β.

Methods

The expression of FAM26F and marker genes was analyzed through Real-time qPCR and western blot.

Results

Our results indicate that the differential expression of FAM26F followed the same trend as that of IRF3 and IFN-β. The in vitro study revealed that, in both HBV infected cell lines, FAM26F expression was significantly down-regulated as compared to uninfected control cells. Treatment of cells with N-acetyl-L-cysteine (NAC), EGTA-AM, BAPTA-AM, and Ru360 significantly upregulated the expression of FAM26F in both the cell lines. Moreover, in in vivo study, FAM26F expression was significantly downregulated in all HBV infected groups as compared to controls (p = 0.0007). The expression was higher in the HBV recovered cases, probably due to the decrease in infection and increase in the immunity of these individuals.

Conclusion

Our study is the first to show the association of FAM26F with HBV infection. It is proposed that FAM26F expression could be an early predictive marker for HBV infection, and thus is worthy of further investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05888-0.

Adipose tissue and insulin resistance in obese

Currently, obesity has become a global health issue and is referred to as an epidemic. Dysfunctional obese adipose tissue plays a pivotal role in the development of insulin resistance. However, the mechanism of how dysfunctional obese-adipose tissue develops insulin-resistant circumstances remains poorly understood. Therefore, this review attempts to highlight the potential mechanisms behind obesity-associated insulin resistance. Multiple risk factors are directly or indirectly associated with the increased risk of obesity; among them, environmental factors, genetics, aging, gut microbiota, and diets are prominent. Once an individual becomes obese, adipocytes increase in their size; therefore, adipose tissues become larger and dysfunctional, recruit macrophages, and then these polarize to pro-inflammatory states. Enlarged adipose tissues release excess free fatty acids (FFAs), reactive oxygen species (ROS), and pro-inflammatory cytokines. Excess systemic FFAs and dietary lipids enter inside the cells of non-adipose organs such as the liver, muscle, and pancreas, and are deposited as ectopic fat, generating lipotoxicity. Toxic lipids dysregulate cellular organelles, e.g., mitochondria, endoplasmic reticulum, and lysosomes. Dysregulated organelles release excess ROS and pro-inflammation, resulting in systemic inflammation. Long term low-grade systemic inflammation prevents insulin from its action in the insulin signaling pathway, disrupts glucose homeostasis, and results in systemic dysregulation. Overall, long-term obesity and overnutrition develop into insulin resistance and chronic low-grade systemic inflammation through lipotoxicity, creating the circumstances to develop clinical conditions. This review also shows that the liver is the most sensitive organ undergoing insulin impairment faster than other organs, and thus, hepatic insulin resistance is the primary event that leads to the subsequent development of peripheral tissue insulin resistance.

Idebenone Protects against Spontaneous Chronic Murine Colitis by Alleviating Endoplasmic Reticulum Stress and Inflammatory Response

Endoplasmic reticulum (ER) stress in intestinal secretory goblet cells has been linked to the development of ulcerative colitis (UC). Emerging evidence suggests that the short chain quinone drug idebenone displays anti-inflammatory activity in addition to its potent antioxidant and mitochondrial electron donor properties. This study evaluated the impact of idebenone in Winnie mice, that are characterized by spontaneous chronic intestinal inflammation and ER stress caused by a missense mutation in the mucin MUC2 gene. Idebenone (200 mg/kg) was orally administered daily to 5-6 weeks old Winnie mice over a period of 21 days. Idebenone treatment substantially improved body weight gain, disease activity index (DAI), colon length and histopathology score. Immunohistochemistry revealed increased expression of MUC2 protein in goblet cells, consistent with increased MUC2 mRNA levels. Furthermore, idebenone significantly reduced the expression of the ER stress markers C/EBP homologous protein (CHOP), activating transcription factor 6 (ATF6) and X-box binding protein-1 (XBP-1) at both mRNA and protein levels. Idebenone also effectively reduced pro-inflammatory cytokine levels in colonic explants. Taken together, these results indicate that idebenone could represent a potential therapeutic approach against human UC by its strong anti-inflammatory activity and its ability to reduce markers of ER stress.

TRAIL Receptors Serve as Stress-Associated Molecular Patterns to Promote ER-Stress-Induced Inflammation

Inflammation triggered by infection or cellular necrosis is initiated by a battery of pattern-recognition receptors, such as Toll-like receptors or IL-1 family receptors. Diverse forms of cell stress, such as ER stress or mitochondrial stress, can also promote inflammatory responses that contribute to the chronic inflammation observed in cancer, obesity, and other conditions. However, the molecular mechanisms of cell-stress-induced inflammation are poorly understood. Here, we show that ER stress initiated NF-κB activation and inflammation through transcriptional upregulation and ligand-independent activation of TRAIL receptors. ER-stress-induced TRAIL receptor activation resulted in caspase-8/FADD/RIPK1-dependent NF-κB activation and inflammatory cytokine production. Silencing or deletion of TRAIL receptors, or their downstream effectors caspase-8, FADD, or RIPK1, suppressed ER-stress-induced inflammation. Furthermore, chemotherapeutic stress-induced inflammatory responses were blunted in DR5/TRAIL-R null animals. We propose that, upon ER stress, TRAIL receptors serve as "stress-associated molecular patterns (SAMPs)" coupling ER stress to NF-κB-dependent inflammation.

Protective effects of curcumin against chronic alcohol-induced liver injury in mice through modulating mitochondrial dysfunction and inhibiting endoplasmic reticulum stress

Background

Curcumin is a major active ingredient extracted from powdered dry rhizome of Curcuma longa. In Ayurveda and traditional Chinese medicine, it has been used as a hepatoprotective agent for centuries. However, the underlying mechanisms are not clear.

Objective

The present study is to investigate the hepatoprotective effects of curcumin in chronic alcohol-induced liver injury and explore its mechanism.

Design

Alcohol-exposed Balb/c mice were treated with curcumin (75 and 150 mg/kg) once per day for 8 weeks. Tissue from individual was fixed with formaldehyde for pathological examination. The activities of mitochondrial antioxidant enzymes, Na⁺/k⁺-ATPase, Ca²⁺-ATPase, and Ca²⁺Mg²⁺-ATPase, were determined. The level of mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (MPTP) opening was also determined. The expression of PGC-1α, NRF1, Mn-SOD, GRP78, PERK, IRE1α, nuclear NF-κB, and phosphorylated IκBα was quantified by western blot. The contents of TNF-α, IL-1β, and IL-6 in the liver were measured using the ELISA method.

Results

Curcumin significantly promoted hepatic mitochondrial function by reducing the opening of MPTP, thus increasing the MMP, promoting the activity of Na⁺/k⁺-ATPase, Ca²⁺-ATPase, and Ca²⁺/Mg²⁺-ATPase, and attenuating oxidative stress. Curcumin upregulated the expression of PGC-1α, NRF1, and Mn-SOD, and downregulated the expression of GRP78, PERK, and IRE1α in hepatic tissue. Curcumin also attenuated inflammation by inhibiting the IκBα–NF-κB pathway, which reduced the production of TNF, IL-1β, and IL-6.

Conclusion

Curcumin attenuates alcohol-induced liver injury via improving mitochondrial function and attenuating endoplasmic reticulum stress and inflammation. This study provides strong evidence for the beneficial effects of curcumin in the treatment of chronic alcohol-induced liver injury.

Calcium Signaling Deficits in Glia and Autophagic Pathways Contributing to Neurodegenerative Disease

SIGNIFICANCE

Numerous cellular processes and signaling mechanisms have been identified that contribute to Alzheimer's disease (AD) pathology; however, a comprehensive or unifying pathway that binds together the major disease features remains elusive. As an upstream mechanism, altered calcium (Ca²⁺) signaling is a common driving force for many pathophysiological events that emerge during normal aging and development of neurodegenerative disease. Recent Advances: Over the previous three decades, accumulated evidence has validated the concept that intracellular Ca²⁺ dysregulation is centrally involved in AD pathogenesis, including the aggregation of pathogenic β-amyloid (Aβ) and phospho-τ species, synapse loss and dysfunction, cognitive impairment, and neurotoxicity.

CRITICAL ISSUES

Although neuronal Ca²⁺ signaling within the cytosol and endoplasmic reticulum (ER) has been well studied, other critical central nervous system-resident cell types affected by aberrant Ca²⁺ signaling, such as astrocytes and microglia, have not been considered as thoroughly. In addition, certain intracellular Ca²⁺-harboring organelles have been well studied, such as the ER and mitochondria; however other critical Ca²⁺-regulated organelles, such as lysosomes and autophagosomes, have only more recently been investigated. In this review, we examine Ca²⁺ dysregulation in microglia and astrocytes, as well as key intracellular organelles important for cellular maintenance and protein handling. Ca²⁺ dysregulation within these non-neuronal cells and organelles is hypothesized to disrupt the effective clearance of misaggregated proteins and cellular signaling pathways needed for memory networks.

FUTURE DIRECTIONS

Overall, we aim to explore how these disrupted mechanisms could be involved in AD pathology and consider their role as potential therapeutic targets. Antioxid. Redox Signal. 29, 1158-1175.

Neuroinflammation and ER-stress are key mechanisms of acute bilirubin toxicity and hearing loss in a mouse model

Hyperbilirubinemia (jaundice) is caused by raised levels of unconjugated bilirubin in the blood. When severe, susceptible brain regions including the cerebellum and auditory brainstem are damaged causing neurological sequelae such as ataxia, hearing loss and kernicterus. The mechanism(s) by which bilirubin exerts its toxic effect have not been completely understood to date. In this study we investigated the acute mechanisms by which bilirubin causes the neurotoxicity that contributes to hearing loss. We developed a novel mouse model that exhibits the neurological features seen in human Bilirubin-Induced Neurological Dysfunction (BIND) syndrome that we assessed with a behavioural score and auditory brainstem responses (ABR). Guided by initial experiments applying bilirubin to cultured cells in vitro, we performed whole genome gene expression measurements on mouse brain tissue (cerebellum and auditory brainstem) following bilirubin exposure to gain mechanistic insights into biochemical processes affected, and investigated further using immunoblotting. We then compared the gene changes induced by bilirubin to bacterial lipopolysaccharide (LPS), a well characterized inducer of neuroinflammation, to assess the degree of similarity between them. Finally, we examined the extent to which genetic perturbation of inflammation and both known and novel anti-inflammatory drugs could protect hearing from bilirubin-induced toxicity. The in vitro results indicated that bilirubin induces changes in gene expression consistent with endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR). These gene changes were similar to the gene expression signature of thapsigargin–a known ER stress inducer. It also induced gene expression changes associated with inflammation and NF-κB activation. The in vivo model showed behavioural impairment and a raised auditory threshold. Whole genome gene expression analysis confirmed inflammation as a key mechanism of bilirubin neurotoxicity in the auditory pathway and shared gene expression hallmarks induced by exposure to bacterial lipopolysaccharide (LPS) a well-characterized inducer of neuroinflammation. Interestingly, bilirubin caused more severe damage to the auditory system than LPS in this model, but consistent with our hypothesis of neuroinflammation being a primary part of bilirubin toxicity, the hearing loss was protected by perturbing the inflammatory response. This was carried out genetically using lipocalin-2 (LCN2)-null mice, which is an inflammatory cytokine highly upregulated in response to bilirubin. Finally, we tested known and novel anti-inflammatory compounds (interfering with NF-κB and TNFα signalling), and also demonstrated protection of the auditory system from bilirubin toxicity. We have developed a novel, reversible, model for jaundice that shows movement impairment and auditory loss consistent with human symptoms. We used this model to establish ER-stress and inflammation as major contributors to bilirubin toxicity. Because of the rapid and reversible onset of toxicity in this novel model it represents a system to screen therapeutic compounds. We have demonstrated this by targeting inflammation genetically and with anti-inflammatory small molecules that offered protection against bilirubin toxicity. This also suggests that anti-inflammatory drugs could be of therapeutic use in hyperbilirubinemia.

Inhibition of the ER stress IRE1α inflammatory pathway protects against cell death in mitochondrial complex I mutant cells

Mitochondrial mutations cause bioenergetic defects associated with failures to use the electron transfer chain and oxidize substrates. These defects are exacerbated under energetic stress conditions and ultimately cause cell deterioration and death. However, little is known about cellular strategies that rescue mitochondrial stress failures and maintain cell survival under these conditions. Here, we have designed and performed a high-throughput chemical screen to identify small molecules that rescue human mitochondrial complex I mutations from energetic stress-induced cell death. The top positive hits were a series of sulfonylureas that efficiently maintain prolonged cell survival and growth under energetic stress conditions. The addition of galactose instead of glucose, to experimentally force mitochondrial respiration, triggered an initial ER stress response that was associated with IRE1α-dependent inflammatory signals including JNK and p38 MAP kinases in mutant cells. Sulfonylureas, similar to inhibition of IRE1α and p38 MAP kinase, potently blocked this ER stress inflammatory and cell death pathway and maintained viability and cell growth under severe energetic stress conditions. These studies reveal that sulfonylureas and specific inhibition of the IRE1α inflammatory pathway protect against cell death and can be used to rescue bioenergetic failures in mitochondrial complex I-mutated cells under stress conditions.

An Update on Autoinflammatory Diseases: Interferonopathies

PURPOSE OF REVIEW

Type I interferons (IFNαβ) induce the expression of hundreds of genes; thus, it is unsurprising that the initiation, transmission, and resolution of the IFNαβ-mediated immune response is tightly controlled. Mutations that alter nucleic acid processing and recognition, ablate IFNαβ-specific negative feedback mechanisms, or result in dysfunction of the proteasome system can all induce pathogenic IFNαβ signalling and are the focus of this review.

RECENT FINDINGS

Recent advances have delineated the precise cytoplasmic mechanisms that facilitate self-DNA to be recognised by cGAS and self-RNA to be recognised by RIG-I or MDA-5. This helps clarify interferonopathies associated with mutations in genes which code for DNase-II and ADAR1, among others. Similarly, loss of function mutations in Pol α, which lowers the presence of antagonistic ligands in the cytosol, or gain of function mutations in RIG-I and MDA-5, result in increased propensity for receptor activation and therefore IFNαβ induction. As the aetiology of monogenic autoinflammatory diseases are uncovered, novel and sometimes unsuspected molecular interactions and signalling pathways are being defined. This review covers developments that have come to light over the past 3 years, with reference to the study of interferonopathies.

The Crosstalk of Endoplasmic Reticulum (ER) Stress Pathways with NF-κB: Complex Mechanisms Relevant for Cancer, Inflammation and Infection

Stressful conditions occuring during cancer, inflammation or infection activate adaptive responses that are controlled by the unfolded protein response (UPR) and the nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB) signaling pathway. These systems can be triggered by chemical compounds but also by cytokines, toll-like receptor ligands, nucleic acids, lipids, bacteria and viruses. Despite representing unique signaling cascades, new data indicate that the UPR and NF-κB pathways converge within the nucleus through ten major transcription factors (TFs), namely activating transcription factor (ATF)4, ATF3, CCAAT/enhancer-binding protein (CEBP) homologous protein (CHOP), X-box-binding protein (XBP)1, ATF6α and the five NF-κB subunits. The combinatorial occupancy of numerous genomic regions (enhancers and promoters) coordinates the transcriptional activation or repression of hundreds of genes that collectively determine the balance between metabolic and inflammatory phenotypes and the extent of apoptosis and autophagy or repair of cell damage and survival. Here, we also discuss results from genetic experiments and chemical activators of endoplasmic reticulum (ER) stress that suggest a link to the cytosolic inhibitor of NF-κB (IκB)α degradation pathway. These data show that the UPR affects this major control point of NF-κB activation through several mechanisms. Taken together, available evidence indicates that the UPR and NF-κB interact at multiple levels. This crosstalk provides ample opportunities to fine-tune cellular stress responses and could also be exploited therapeutically in the future.

Regulation of Cytokine Production by the Unfolded Protein Response; Implications for Infection and Autoimmunity

Protein folding in the endoplasmic reticulum (ER) is an essential cell function. To safeguard this process in the face of environmental threats and internal stressors, cells mount an evolutionarily conserved response known as the unfolded protein response (UPR). Invading pathogens induce cellular stress that impacts protein folding, thus the UPR is well situated to sense danger and contribute to immune responses. Cytokines (inflammatory cytokines and interferons) critically mediate host defense against pathogens, but when aberrantly produced, may also drive pathologic inflammation. The UPR influences cytokine production on multiple levels, from stimulation of pattern recognition receptors, to modulation of inflammatory signaling pathways, and the regulation of cytokine transcription factors. This review will focus on the mechanisms underlying cytokine regulation by the UPR, and the repercussions of this relationship for infection and autoimmune/autoinflammatory diseases. Interrogation of viral and bacterial infections has revealed increasing numbers of examples where pathogens induce or modulate the UPR and implicated UPR-modulated cytokines in host response. The flip side of this coin, the UPR/ER stress responses have been increasingly recognized in a variety of autoimmune and inflammatory diseases. Examples include monogenic disorders of ER function, diseases linked to misfolding protein (HLA-B27 and spondyloarthritis), diseases directly implicating UPR and autophagy genes (inflammatory bowel disease), and autoimmune diseases targeting highly secretory cells (e.g., diabetes). Given the burgeoning interest in pharmacologically targeting the UPR, greater discernment is needed regarding how the UPR regulates cytokine production during specific infections and autoimmune processes, and the relative place of this interaction in pathogenesis.

Mechanisms regulating immune surveillance of cellular stress in cancer

The purpose of this review is to explore immune-mediated mechanisms of stress surveillance in cancer, with particular emphasis on the idea that all cancers have classical hallmarks (Hanahan and Weinberg in Cell 100:57-70, 67; Cell 144:646-674, 68) that could be interrelated. We postulate that hallmarks of cancer associated with cellular stress pathways (Luo et al. in Cell 136:823-837, 101) including oxidative stress, proteotoxic stress, mitotic stress, DNA damage, and metabolic stress could define and modulate the inflammatory component of cancer. As such, the overarching goal of this review is to define the types of cellular stress that cancer cells undergo, and then to explore mechanisms by which immune cells recognize, respond to, and are affected by each stress response.

Role of endoplasmic reticulum stress signalling in diabetic endothelial dysfunction and atherosclerosis

It is well established that diabetes mellitus accelerates atherosclerotic vascular disease. Endothelial injury has been proposed to be the initial event in the pathogenesis of atherosclerosis. Endothelium not only acts as a semi-selective barrier but also serves physiological and metabolic functions. Diabetes or high glucose in circulation triggers a series of intracellular responses and organ damage such as endothelial dysfunction and apoptosis. One such response is high glucose-induced chronic endoplasmic reticulum stress in the endothelium. The unfolded protein response is an acute reaction that enables cells to overcome endoplasmic reticulum stress. However, when chronically persistent, endoplasmic reticulum stress response could ultimately lead to endothelial dysfunction and atherosclerosis. Herein, we discuss the scientific advances in understanding endoplasmic reticulum stress-induced endothelial dysfunction, the pathogenesis of diabetes-accelerated atherosclerosis and endoplasmic reticulum stress as a potential target in therapies for diabetic atherosclerosis.

The Pathogenesis of Alzheimers Disease—Is It a Lifelong “Calciumopathy”?

Alzheimer's disease (AD) is a fatal neurodegenerative disorder that has no known cure, nor is there a clear mechanistic understanding of the disease process itself. Although amyloid plaques, neurofibrillary tangles, and cognitive decline are late-stage markers of the disease, it is unclear how they are initially generated, and if they represent a cause, effect, or end phase in the pathology process. Recent studies in AD models have identified marked dysregulations in calcium signaling and related downstream pathways, which occur long before the diagnostic histopathological or cognitive changes. Under normal conditions, intracellular calcium signals are coupled to effectors that maintain a healthy physiological state. Consequently, sustained up-regulation of calcium may have pathophysiological consequences. Indeed, upon reviewing the current body of literature, increased calcium levels are functionally linked to the major features and risk factors of AD: ApoE4 expression, presenilin and APP mutations, beta amyloid plaques, hyperphosphorylation of tau, apoptosis, and synaptic dysfunction. In turn, the histopathological features of AD, once formed, are capable of further increasing calcium levels, leading to a rapid feed-forward acceleration once the disease process has taken hold. The views proposed here consider that AD pathogenesis reflects long-term calcium dysregulations that ultimately serve an enabling role in the disease process. Therefore, “Calcinists” do not necessarily reject βAptist or Tauist doctrine, but rather believe that their genesis is associated with earlier calcium signaling dysregulations. NEUROSCIENTIST 13(5):546—559, 2007.

Copa Syndrome: a Novel Autosomal Dominant Immune Dysregulatory Disease

Inherently defective immunity typically results in either ineffective host defense, immune regulation, or both. As a category of primary immunodeficiency diseases, those that impair immune regulation can lead to autoimmunity and/or autoinflammation. In this review we focus on one of the most recently discovered primary immunodeficiencies that leads to immune dysregulation: "Copa syndrome". Copa syndrome is named for the gene mutated in the disease, which encodes the alpha subunit of the coatomer complex-I that, in aggregate, is devoted to transiting molecular cargo from the Golgi complex to the endoplasmic reticulum (ER). Copa syndrome is autosomal dominant with variable expressivity and results from mutations affecting a narrow amino acid stretch in the COPA gene-encoding COPα protein. Patients with these mutations typically develop arthritis and interstitial lung disease with pulmonary hemorrhage representing a striking feature. Immunologically Copa syndrome is associated with autoantibody development, increased Th17 cells and pro-inflammatory cytokine expression including IL-1β and IL-6. Insights have also been gained into the underlying mechanism of Copa syndrome, which include excessive ER stress owing to the impaired return of proteins from the Golgi, and presumably resulting aberrant cellular autophagy. As such it represents a novel cellular disorder of intracellular trafficking associated with a specific clinical presentation and phenotype.

The Unfolded Protein Response in Homeostasis and Modulation of Mammalian Immune Cells

The endoplasmic reticulum (ER) plays important roles in eukaryotic protein folding and lipid biosynthesis. Several exogenous and endogenous cellular sources of stress can perturb ER homeostasis leading to the accumulation of unfolded proteins in the lumen. Unfolded protein accumulation triggers a signal-transduction cascade known as the unfolded protein response (UPR), an adaptive mechanism which aims to protect cells from protein aggregates and to restore ER functions. Further to this protective mechanism, in immune cells, UPR molecular effectors have been shown to participate in a wide range of biological processes such as cell differentiation, survival and immunoglobulin and cytokine production. Recent findings also highlight the involvement of the UPR machinery in the maturational program and antigen presentation capacities of dendritic cells. UPR is therefore a key element in immune system homeostasis with direct implications on both adaptive and innate immune responses. The present review summarizes the knowledge on the emerging roles of UPR signaling cascades in mammalian immune cells as well as the consequences of their dysregulation in relation to the pathogenesis of several diseases.

Oxidative and endoplasmic reticulum stress in β-cell dysfunction in diabetes

The inability of pancreatic β-cells to make sufficient insulin to control blood sugar is a central feature of the aetiology of most forms of diabetes. In this review we focus on the deleterious effects of oxidative stress and endoplasmic reticulum (ER) stress on β-cell insulin biosynthesis and secretion and on inflammatory signalling and apoptosis with a particular emphasis on type 2 diabetes (T2D). We argue that oxidative stress and ER stress are closely entwined phenomena fundamentally involved in β-cell dysfunction by direct effects on insulin biosynthesis and due to consequences of the ER stress-induced unfolded protein response. We summarise evidence that, although these phenomenon can be driven by intrinsic β-cell defects in rare forms of diabetes, in T2D β-cell stress is driven by a range of local environmental factors including increased drivers of insulin biosynthesis, glucolipotoxicity and inflammatory cytokines. We describe our recent findings that a range of inflammatory cytokines contribute to β-cell stress in diabetes and our discovery that interleukin 22 protects β-cells from oxidative stress regardless of the environmental triggers and can correct much of diabetes pathophysiology in animal models. Finally we summarise evidence that β-cell dysfunction is reversible in T2D and discuss therapeutic opportunities for relieving oxidative and ER stress and restoring glycaemic control.

The clerodane diterpene casearin J induces apoptosis of T-ALL cells through SERCA inhibition, oxidative stress, and interference with Notch1 signaling

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy that preferentially affects children and adolescents. Over 50% of human T-ALLs possess activating mutations of Notch1. The clerodane diterpene casearin J (CJ) is a natural product that inhibits the sarcoendoplasmatic reticulum calcium ATPase (SERCA) pump and induces cell death in leukemia cells, but the molecular mechanism of cytotoxicity remains poorly understood. Here we show that owing to SERCA pump inhibition, CJ induces depletion of the endoplasmic reticulum calcium pools, oxidative stress, and apoptosis via the intrinsic signaling pathway. Moreover, Notch1 signaling is reduced in T-ALL cells with auto-activating mutations in the HD-domain of Notch1, but not in cells that do not depend on Notch1 signaling. CJ also provoked a slight activation of NF-κB, and consistent with this notion a combined treatment of CJ and the NF-κB inhibitor parthenolide (Pt) led to a remarkable synergistic cell death in T-ALL cells. Altogether, our data support the concept that inhibition of the SERCA pump may be a novel strategy for the treatment of T-ALL with HD-domain-mutant Notch1 receptors and that additional treatment with the NF-κB inhibitor parthenolide may have further therapeutic benefits.

BAX inhibitor-1 is a Ca(2+) channel critically important for immune cell function and survival

The endoplasmic reticulum (ER) serves as the major intracellular Ca(2+) store and has a role in the synthesis and folding of proteins. BAX (BCL2-associated X protein) inhibitor-1 (BI-1) is a Ca(2+) leak channel also implicated in the response against protein misfolding, thereby connecting the Ca(2+) store and protein-folding functions of the ER. We found that BI-1-deficient mice suffer from leukopenia and erythrocytosis, have an increased number of splenic marginal zone B cells and higher abundance and nuclear translocation of NF-κB (nuclear factor-κ light-chain enhancer of activated B cells) proteins, correlating with increased cytosolic and ER Ca(2+) levels. When put into culture, purified knockout T cells and even more so B cells die spontaneously. This is preceded by increased activity of the mitochondrial initiator caspase-9 and correlated with a significant surge in mitochondrial Ca(2+) levels, suggesting an exhausted mitochondrial Ca(2+) buffer capacity as the underlying cause for cell death in vitro. In vivo, T-cell-dependent experimental autoimmune encephalomyelitis and B-cell-dependent antibody production are attenuated, corroborating the ex vivo results. These results suggest that BI-1 has a major role in the functioning of the adaptive immune system by regulating intracellular Ca(2+) homeostasis in lymphocytes.

Translating endoplasmic reticulum biology into the clinic: a role for ER-targeted natural products?

ER stress has been identified as a hallmark, and sometimes trigger, of several pathologies, notably cancer, inflammation and neurodegenerative diseases like Alzheimer's and Parkinson's. Among the molecules described in literature known to affect ER function, the majority are natural products, suggesting that natural molecules may constitute a significant arsenal of chemical entities for modulating this cellular target. In this review, we will start by presenting the current knowledge of ER biology and the hallmarks of ER stress, thus paving the way for presenting the natural products that have been described as being ER modulators, either stress inducers or ER protectors. The chemistry, distribution and mechanism of action of these compounds will be presented and discussed.

Endoplasmic reticulum stress signaling in mammalian oocytes and embryos: life in balance

Mammalian oocytes and embryos are exquisitely sensitive to a wide range of insults related to physical stress, chemical exposure, and exposures to adverse maternal nutrition or health status. Although cells manifest specific responses to various stressors, many of these stressors intersect at the endoplasmic reticulum (ER), where disruptions in protein folding and production of reactive oxygen species initiate downstream signaling events. These signals modulate mRNA translation and gene transcription, leading to recovery, activation of autophagy, or with severe and prolonged stress, apoptosis. ER stress signaling has recently come to the fore as a major contributor to embryo demise. Accordingly, agents that modulate or inhibit ER stress signaling have yielded beneficial effects on embryo survival and long-term developmental potential. We review here the mechanisms of ER stress signaling, their connections to mammalian oocytes and embryos, and the promising indications that interventions in this pathway may provide new opportunities for improving mammalian reproduction and health.

Endoplasmic reticulum stress in immunity

Immune responses occur in the midst of a variety of cellular stresses that can severely perturb endoplasmic reticulum (ER) function. The unfolded protein response is a three-pronged signaling axis dedicated to preserving ER homeostasis. In this review, we highlight many important and emerging functional roles for ER stress in immunity, focusing on how the bidirectional cross talk between immunological processes and basic cell biology leads to pleiotropic signaling outcomes and enhanced sensitivity to inflammatory stimuli. We also discuss how dysregulated ER stress responses can provoke many diseases, including autoimmunity, firmly positioning the unfolded protein response as a major therapeutic target in human disease.

Glycemic control in diabetes is restored by therapeutic manipulation of cytokines that regulate beta cell stress

In type 2 diabetes, hyperglycemia is present when an increased demand for insulin, typically due to insulin resistance, is not met as a result of progressive pancreatic beta cell dysfunction. This defect in beta cell activity is typically characterized by impaired insulin biosynthesis and secretion, usually accompanied by oxidative and endoplasmic reticulum (ER) stress. We demonstrate that multiple inflammatory cytokines elevated in diabetic pancreatic islets induce beta cell oxidative and ER stress, with interleukin-23 (IL-23), IL-24 and IL-33 being the most potent. Conversely, we show that islet-endogenous and exogenous IL-22, by regulating oxidative stress pathways, suppresses oxidative and ER stress caused by cytokines or glucolipotoxicity in mouse and human beta cells. In obese mice, antibody neutralization of IL-23 or IL-24 partially reduced beta cell ER stress and improved glucose tolerance, whereas IL-22 administration modulated oxidative stress regulatory genes in islets, suppressed ER stress and inflammation, promoted secretion of high-quality efficacious insulin and fully restored glucose homeostasis followed by restitution of insulin sensitivity. Thus, therapeutic manipulation of immune regulators of beta cell stress reverses the hyperglycemia central to diabetes pathology.

Human Ebola virus infection in West Africa: a review of available therapeutic agents that target different steps of the life cycle of Ebola virus

The recent outbreak of the human Zaire ebolavirus (EBOV) epidemic is spiraling out of control in West Africa. Human EBOV hemorrhagic fever has a case fatality rate of up to 90%. The EBOV is classified as a biosafety level 4 pathogen and is considered a category A agent of bioterrorism by Centers for Disease Control and Prevention, with no approved therapies and vaccines available for its treatment apart from supportive care. Although several promising therapeutic agents and vaccines against EBOV are undergoing the Phase I human trial, the current epidemic might be outpacing the speed at which drugs and vaccines can be produced. Like all viruses, the EBOV largely relies on host cell factors and physiological processes for its entry, replication, and egress. We have reviewed currently available therapeutic agents that have been shown to be effective in suppressing the proliferation of the EBOV in cell cultures or animal studies. Most of the therapeutic agents in this review are directed against non-mutable targets of the host, which is independent of viral mutation. These medications are approved by the Food and Drug Administration (FDA) for the treatment of other diseases. They are available and stockpileable for immediate use. They may also have a complementary role to those therapeutic agents under development that are directed against the mutable targets of the EBOV.

Function of monocytes and monocyte-derived macrophages in α1-antitrypsin deficiency

α1-antitrypsin deficiency is the most widely recognised genetic disorder causing chronic obstructive pulmonary disease (COPD). Mutant Z α1-antitrypsin expression has previously been linked to intracellular accumulation and polymerisation of this proteinase inhibitor. Subsequently, this has been described to underlie an exaggerated endoplasmic reticulum stress response and enhanced nuclear factor-κB signalling. However, whether monocyte-derived macrophages display the same features remains unknown.

Monocytes from homozygous PiZZ α1-antitrypsin deficiency patients and PiMM controls were cultured for 6 days in the presence of granulocyte-macrophage or macrophage colony-stimulating factor to obtain pro- and anti-inflammatory macrophages (mφ-1 and mφ-2, respectively).

We first showed that, in contrast to monocytes, pre-stressed mφ-1 and mφ-2 from healthy blood donors display an enhanced endoplasmic reticulum stress response upon a lipopolysaccharide trigger (XBP1 splicing, CHOP, GADD34 and GRP78 mRNA). However, this endoplasmic reticulum stress response did not differ between monocyte-derived macrophages and monocytes from ZZ patients compared to MM controls. Furthermore, these ZZ cells do not secrete higher cytokine levels, and α1-antitrypsin polymers were not detectable by ELISA.

These data suggest that monocyte-derived macrophages are not the local source of Z α1-antitrypsin polymers found in the lung and that endoplasmic reticulum stress and pro-inflammatory cytokine release is not altered.

Cellular stress response and pulmonary inflammation

Innate immunity as the first line of the immune system, provides initial protection against various pathogens and infections. Recent studies suggest a link between cell stress response and immune response upon exogenous insults in the lung. The key proteins in cellular stress responses were demonstrated to be involved in the activation and regulation of the immune signaling pathways. Further research on the function of these stress proteins in innate immunity defenses, particularly in pulmonary diseases and inflammation may help to clarify the disease pathogenesis and provide potential therapeutic treatments for various infectious and inflammatory lung diseases.

A molecular web: endoplasmic reticulum stress, inflammation, and oxidative stress

Execution of fundamental cellular functions demands regulated protein folding homeostasis. Endoplasmic reticulum (ER) is an active organelle existing to implement this function by folding and modifying secretory and membrane proteins. Loss of protein folding homeostasis is central to various diseases and budding evidences suggest ER stress as being a major contributor in the development or pathology of a diseased state besides other cellular stresses. The trigger for diseases may be diverse but, inflammation and/or ER stress may be basic mechanisms increasing the severity or complicating the condition of the disease. Chronic ER stress and activation of the unfolded-protein response (UPR) through endogenous or exogenous insults may result in impaired calcium and redox homeostasis, oxidative stress via protein overload thereby also influencing vital mitochondrial functions. Calcium released from the ER augments the production of mitochondrial Reactive Oxygen Species (ROS). Toxic accumulation of ROS within ER and mitochondria disturbs fundamental organelle functions. Sustained ER stress is known to potentially elicit inflammatory responses via UPR pathways. Additionally, ROS generated through inflammation or mitochondrial dysfunction could accelerate ER malfunction. Dysfunctional UPR pathways have been associated with a wide range of diseases including several neurodegenerative diseases, stroke, metabolic disorders, cancer, inflammatory disease, diabetes mellitus, cardiovascular disease, and others. In this review, we have discussed the UPR signaling pathways, and networking between ER stress-induced inflammatory pathways, oxidative stress, and mitochondrial signaling events, which further induce or exacerbate ER stress.

Potential For Cell-mediated Immune Responses In Mouse Models Of Pelizaeus-Merzbacher Disease

Although activation of the innate and adaptive arms of the immune system are undoubtedly involved in the pathophysiology of neurodegenerative diseases, it is unclear whether immune system activation is a primary or secondary event. Increasingly, published studies link primary metabolic stress to secondary inflammatory responses inside and outside of the nervous system. In this study, we show that the metabolic stress pathway known as the unfolded protein response (UPR) leads to secondary activation of the immune system. First, we observe innate immune system activation in autopsy specimens from Pelizaeus-Merzbacher disease (PMD) patients and mouse models stemming from PLP1 gene mutations. Second, missense mutations in mildly- and severely-affected Plp1-mutant mice exhibit immune-associated expression profiles with greater disease severity causing an increasingly proinflammatory environment. Third, and unexpectedly, we find little evidence for dysregulated expression of major antioxidant pathways, suggesting that the unfolded protein and oxidative stress responses are separable. Together, these data show that UPR activation can precede innate and/or adaptive immune system activation and that neuroinflammation can be titrated by metabolic stress in oligodendrocytes. Whether or not such activation leads to autoimmune disease in humans is unclear, but the case report of steroid-mitigated symptoms in a PMD patient initially diagnosed with multiple sclerosis lends support.

Effects of magnesium deficiency--more than skin deep

Dead Sea and magnesium salt therapy are two of the oldest forms of treatment for skin disease and several other disorders, supported by a body of largely anecdotal evidence. In this paper we review possible pathways for penetration of magnesium ions through the epidermis to reach the circulation, in turn replenishing cellular magnesium levels. We also discuss mechanisms for intercellular movement of magnesium ions and possible mechanisms for the interaction between magnesium ions and inflammatory mediators. Upon addition of magnesium ions in vitro, the expression of inflammatory mediators such as tumour necrosis factor α (TNFα) and nuclear factor κβ (NFκβ) is down regulated. Dysregulation of these and other inflammatory mediators has been linked to several inflammatory disorders, including asthma, arthritis, atherosclerosis and neuroinflammation.

Disparity among neural injury models and the unfolded protein response

Endoplasmic reticulum stress is activated following both stroke and traumatic brain injury producing reactive oxgygen species, increasing intracellular calcium levels, and inducing inflammation; however, the timing and duration of activation varies between injuries. Preventing the immediate effects of ischemic/reperfusion injury or traumatic brain injury is challenging due to short onset of injury, but mitigating the secondary effects is a therapeutically targetable option. Preventative therapies using pharmacological agents have been utilized in pre-clinical models of neural injury to ameliorate secondary effects such as apoptosis and neurodegeneration. The connection between ER stress activation, apoptosis, and subsequent neurodegeneration has been proposed, but not yet causally linked. Researchers are now pursuing effective treatment strategies to suppress the secondary effects of neural injury in order to mitigate the development of chronic deficits. Secondary effects such as endoplasimic reticulum stress and neuroinflammation can be prevented in pre-clinical models, but the results have yet to translate to meaningful treatment options for patients. Evidence suggests that targeting the right transcription factors, at the right time, will aid in the prevention of apoptosis and neurodegenerative disease development following neural injury. In this review, we examine therapeutic approaches that target secondary injury and how these may correlate to better treatment options for patients.

Nuclear factor-κB as a link between endoplasmic reticulum stress and inflammation during cardiomyocyte hypoxia/reoxygenation

Endoplasmic reticulum stress (ERS) can initiate inflammation, and the coupling of these responses is thought to be fundamental to the pathogenesis of cardiovascular disease. However, the mechanism linking ERS and inflammation in myocardial ischemia/reperfusion needs further investigation. Cultured cardiomyocytes were pretreated with SP600125 or salubrinal, followed by tunicamycin to clarify the involvement of the IRE1α and PERK pathways in ERS inflammation. The cardiomyocytes were given hypoxia/reoxygenation (H/R), and the effects of the NF-κB inhibitor, SN50, were followed. GRP78 protein levels were similar in the tunicamycin (Tm), salubrinal, and SP600125 groups, but were lower in cells treated with SN50. SN50 might effectively block the H/R-induced link between ERS and inflammation in cardiomyocytes by decreasing GRP78. This knowledge will aid in the development of therapies for myocardial ischemia/reperfusion injury.

Inositol-requiring enzyme 1 inhibits respiratory syncytial virus replication

Despite being a major health problem, respiratory syncytial virus (RSV) infections remain without specific therapy. Identification of novel host cellular responses that play a role in the pathogenesis of RSV infection is needed for therapeutic development. The endoplasmic reticulum (ER) stress response is an evolutionarily conserved cellular signaling cascade that has been implicated in multiple biological phenomena, including the pathogenesis of some viral infections. In this study, we investigate the role of the ER stress response in RSV infection using an in vitro A549 cell culture model. We found that RSV infection induces a non-canonical ER stress response with preferential activation of the inositol-requiring enzyme 1 (IRE1) and activated transcription factor 6 (ATF6) pathways with no concomitant significant activation of the protein kinase R-like ER kinase (PERK) pathway. Furthermore, we discovered that IRE1 has an inhibitory effect on RSV replication. Our data characterize, for the first time, the nature of the ER stress response in the setting of RSV infection and identify the IRE1 stress pathway as a novel cellular anti-RSV defense mechanism.

Effect of magnetic modulation of mitochondrial voltage-dependent anion channel 2 against beta-amyloid induced neurotoxicity

The capture of VDAC2 channel with BMPs–VDAC2 antibody complexes significantly decreases the expressed intracellular calcium levels induced by Aβ.

Polymorphisms of ATF6B Are Potentially Associated With FEV1 Decline by Aspirin Provocation in Asthmatics

Purpose

Endoplasmic reticulum (ER) stress has recently been observed to activate NF-kappaB and induce inflammatory responses such as asthma. Activating transcription factor 6β (ATF6B) is known to regulate ATFα-mediated ER stress response. The aim of this study is to investigate the associations of ATF6B genetic variants with aspirin-exacerbated respiratory disease (AERD) and its major phenotype, % decline of FEV1 by aspirin provocation.

Methods

Four common single nucleotide polymorphisms (SNPs) of ATF6B were genotyped and statistically analyzed in 93 AERD patients and 96 aspirin-tolerant asthma (ATA) as controls.

Results

Logistic analysis revealed that 2 SNPs (rs2228628 and rs8111, P=0.008; corrected P=0.03) and 1 haplotype (ATF6B-ht4, P=0.005; corrected P=0.02) were significantly associated with % decline of FEV1 by aspirin provocation, whereas ATF6B polymorphisms and haplotypes were not associated with the risk of AERD.

Conclusions

Although further functional and replication studies are needed, our preliminary findings suggest that ATF6B may be related to obstructive phenotypes in response to aspirin exposure in adult asthmatics.

Endoplasmic reticulum stress is sufficient for the induction of IL-1β production via activation of the NF-κB and inflammasome pathways

The mechanisms underlying pathophysiological states such as metabolic syndrome and obesity include endoplasmic reticulum (ER) stress and aberrant inflammatory responses. ER stress results from the accumulation of misfolded proteins during stress conditions. However, the precise mechanisms by which ER stress modulates inflammation remain incompletely understood. In this study, we hypothesized that ER stress alone could represent a sufficient signal for the modulation of inflammasome-dependent cytokine responses. We found that several ER stress-inducing chemicals and the free fatty acid palmitate can trigger IL-1β secretion in various cell types, including monocytic leukemia cells, primary macrophages and differentiated adipocytes. We show that ER stress primes cells for the expression of pro-IL-1β via NF-κB activation and promotes IL-1β secretion. Enhanced IL-1β secretion depended on the activation of the NLRP3 inflammasome through a mechanism involving reactive oxygen species formation and activation of thioredoxin-interacting protein. Chemical chaperone treatment and the pharmacological application of carbon monoxide inhibited IL-1β secretion in response to ER stress. Our results provide a mechanistic link between ER stress and the regulation of inflammation, and suggest that modulation of ER stress may provide a therapeutic opportunity to block progression of low grade chronic inflammation to metabolic syndrome.

Cellular stress response and innate immune signaling: integrating pathways in host defense and inflammation

Extensive research in the past decade has identified innate immune recognition receptors and intracellular signaling pathways that culminate in inflammatory responses. Besides its role in cytoprotection, the importance of cell stress in inflammation and host defense against pathogens is emerging. Recent studies have shown that proteins in cellular stress responses, including the heat shock response, ER stress response, and DNA damage response, interact with and regulate signaling intermediates involved in the activation of innate and adaptive immune responses. The effect of such regulation by cell stress proteins may dictate the inflammatory profile of the immune response during infection and disease. In this review, we describe the regulation of innate immune cell activation by cell stress pathways, present detailed descriptions of the types of stress response proteins and their crosstalk with immune signaling intermediates that are essential in host defense, and illustrate the relevance of these interactions in diseases characteristic of aberrant immune responses, such as chronic inflammatory diseases, autoimmune disorders, and cancer. Understanding the crosstalk between cellular stress proteins and immune signaling may have translational implications for designing more effective regimens to treat immune disorders.