Coupling endoplasmic reticulum stress to the cell death program

Paving the Road Toward Exploiting the Therapeutic Effects of Ginsenosides: An Emphasis on Autophagy and Endoplasmic Reticulum Stress

Programmed cell death processes such as apoptosis and autophagy strongly contribute to the onset and progression of cancer. Along with these lines, modulation of cell death mechanisms to combat cancer cells and elimination of resistance to apoptosis is of great interest. It appears that modulation of autophagy and endoplasmic reticulum (ER) stress with specific agents would be beneficial in the treatment of several disorders. Interestingly, it has been suggested that herbal natural products may be suitable candidates for the modulation of these processes due to few side effects and significant therapeutic potential. Ginsenosides are derivatives of ginseng and exert modulatory effects on the molecular mechanisms associated with autophagy and ER stress. Ginsenosides act as smart phytochemicals that confer their effects by up-regulating ATG proteins and converting LC3-I to -II, which results in maturation of autophagosomes. Not only do ginsenosides promote autophagy but they also possess protective and therapeutic properties due to their capacity to modulate ER stress and up- and down-regulate and/or dephosphorylate UPR transducers such as IRE1, PERK, and ATF6. Thus, it would appear that ginsenosides are promising agents to potentially restore tissue malfunction and possibly eliminate cancer.

Transcriptome analysis of cadmium exposure in kidney fibroblast cells of the North Atlantic Right Whale (Eubalaena glacialis)

An 8X15k oligonucleotide microarray was developed consisting of 2334 Eubalaena glacialis probes and 2166 Tursiops truncatus probes and used to measure the effects, at transcriptomic level, of cadmium exposure in right whale kidney fibroblast cells. Cells were exposed to three concentrations (1 μM, 0.1 μM, and 0.01 μM) of cadmium chloride (CdCl₂) for three exposure times (1, 4, and 24 h). Cells exposed to 1 μM CdCl₂ for 4 h and 24 h showed upregulated genes involved in protection from metal toxicity and oxidative stress, protein renaturation, apoptosis inhibition, as well as several regulators of cellular processes. Downregulated genes represented a suite of functions including cell proliferation, transcription regulation, actin polymerization, and stress fiber synthesis. The collection of differentially expressed genes in this study support proposed mechanisms of cadmium-induced apoptosis such as ubiquitin proteasome system disruption, Ca²⁺ homeostasis interference, mitochondrial membrane potential collapse, reactive oxygen species (ROS) production, and cell cycle arrest. The results also have confirmed the right whale microarray as a reproducible tool in measuring differentiated gene expression that could be a valuable asset for transcriptome analysis of other baleen whales and potential health assessment protocols.

Store operated calcium channels in cancer progression

In recent decades cancer emerged as one of the leading causes of death in the developed countries, with some types of cancer contributing to the top 10 causes of death on the list of the World Health Organization. Carcinogenesis, a malignant transformation causing formation of tumors in normal tissues, is associated with changes in the cell cycle caused by suppression of signaling pathways leading to cell death and facilitation of those enhancing proliferation. Further progression of cancer, during which benign tumors acquire more aggressive phenotypes, is characterized by metastatic dissemination through the body driven by augmented motility and invasiveness of cancer cells. All these processes are associated with alterations in calcium homeostasis in cancer cells, which promote their proliferation, motility and invasion, and dissuade cell death or cell cycle arrest. Remodeling of store-operated calcium entry (SOCE), one of the major pathways regulating intracellular Ca²⁺ concentration ([Ca²⁺]_i), manifests a key event in many of these processes. This review systematizes current knowledge on the mechanisms recruiting SOCE-related proteins in carcinogenesis and cancer progression.

Increased Levels of ER Stress and Apoptosis in a Sheep Model for Pulmonary Fibrosis Are Alleviated by In Vivo Blockade of the KCa3.1 Ion Channel

Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease, characterized by progressive damage to the lung tissues. Apoptosis and endoplasmic reticulum stress (ER stress) in type II alveolar epithelial cells (AECs) and lung macrophages have been linked with the development of IPF. Therefore, apoptosis- and ER stress-targeted therapies have drawn attention as potential avenues for treatment of IPF. The calcium-activated potassium ion channel KCa3.1 has been proposed as a potential therapeutic target for fibrotic diseases including IPF. While KCa3.1 is expressed in AECs and macrophages, its influence on ER stress and apoptosis during the disease process is unclear. We utilized a novel sheep model of pulmonary fibrosis to demonstrate that apoptosis and ER stress occur in type II AECs and macrophages in sheep with bleomycin-induced lung fibrosis. Apoptosis in type II AEC and macrophages was identified using the TUNEL method of tagging fragmented nuclear DNA, while ER stress was characterized by increased expression of GRP-78 ER chaperone proteins. We demonstrated that apoptosis and ER stress in type II AECs and macrophages increased significantly 2 weeks after the final bleomycin infusion and remained high for up to 7 weeks post-bleomycin injury. Senicapoc treatment significantly reduced the rates of ER stress in type II AECs and macrophages that were resident in bleomycin-infused lung segments. There were also significant reductions in the rates of apoptosis of type II AECs and macrophages in the lung segments of senicapoc-treated sheep. In vivo blockade of the KCa3.1 ion channel alleviates the ER stress and apoptosis in type II AECs and macrophages, and this effect potentially contributes to the anti-fibrotic effects of senicapoc.

Alpha-Lipoic Acid Attenuates Cadmium- and Lead-Induced Neurotoxicity by Inhibiting Both Endoplasmic-Reticulum Stress and Activation of Fas/FasL and Mitochondrial Apoptotic Pathways in Rat Cerebral Cortex

Although many studies have reported toxic effects of cadmium (Cd) and lead (Pb) in the central nervous system, few studies have investigated the combined toxicity of Cd and Pb. The mechanisms by which these combined heavy metals induce toxicity, as well as effective means to exert neuroprotection from these agents, remain poorly understood. To investigate the protective effects of alpha-lipoic acid (α-LA) on Cd- and/or Pb-induced cortical damage in rats, 48 Sprague-Dawley rats were exposed to drinking water containing 50 mg/L of Cd and/or 300 mg/L of Pb for 12 weeks, in the presence or absence of α-LA co-treatment (50 mg/kg) via gavage. We observed that exposure to Cd and/or Pb decreased the brain weight/body weight ratio and increased Cd and/or Pb contents as well as ultrastructural damage to the cerebral cortex. Cd and/or Pb also induced endoplasmic-reticulum (ER) stress and activated Fas (CD95/APO-1)/Fas ligand (FasL) and mitochondrial apoptotic pathways. Furthermore, co-treatment of Cd and Pb further exacerbated part of these phenotypes than treatment of Cd or Pb alone. However, simultaneous supplementation with α-LA attenuated Cd and/or Pb-induced neurotoxicity by increasing the brain weight/body weight ratio, reducing Cd and/or Pb contents, ameliorating both nuclear/mitochondrial damage and ER stress, and attenuating activation of Fas/FasL and mitochondrial apoptotic pathways. Collectively, our results indicate that the accumulation of Cd and/or Pb causes cortical damage and that α-LA exerts protection against Cd- and/or Pb-induced neurotoxicity. These findings highlight that α-LA may be exploited for the treatment and prevention of Cd- and/or Pb-induced neurotoxicity.

Crosstalk between MicroRNA and Oxidative Stress in Primary Open-Angle Glaucoma

Reactive oxygen species (ROS) plays a key role in the pathogenesis of primary open-angle glaucoma (POAG), a chronic neurodegenerative disease that damages the trabecular meshwork (TM) cells, inducing apoptosis of the retinal ganglion cells (RGC), deteriorating the optic nerve head, and leading to blindness. Aqueous humor (AH) outflow resistance and intraocular pressure (IOP) elevation contribute to disease progression. Nevertheless, despite the existence of pharmacological and surgical treatments, there is room for the development of additional treatment approaches. The following review is aimed at investigating the role of different microRNAs (miRNAs) in the expression of genes and proteins involved in the regulation of inflammatory and degenerative processes, focusing on the delicate balance of synthesis and deposition of extracellular matrix (ECM) regulated by chronic oxidative stress in POAG related tissues. The neutralizing activity of a couple of miRNAs was described, suggesting effective downregulation of pro-inflammatory and pro-fibrotic signaling pathways, including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), transforming growth factor-beta 2 (TGF-β2), Wnt/β-Catenin, and PI3K/AKT. In addition, with regards to the elevated IOP in many POAG patients due to increased outflow resistance, Collagen type I degradation was stimulated by some miRNAs and prevented ECM deposition in TM cells. Mitochondrial dysfunction as a consequence of oxidative stress was suppressed following exposure to different miRNAs. In contrast, increased oxidative damage by inhibiting the mTOR signaling pathway was described as part of the action of selected miRNAs. Summarizing, specific miRNAs may be promising therapeutic targets for lowering or preventing oxidative stress injury in POAG patients.

The Impacts of Unfolded Protein Response in the Retinal Cells During Diabetes: Possible Implications on Diabetic Retinopathy Development

Diabetic retinopathy (DR) is a vision-threatening, chronic, and challenging eye disease in the diabetic population. Despite recent advancements in the clinical management of diabetes, DR remains the major cause of blindness in working-age adults. A better understanding of the molecular and cellular basis of DR development will aid in identifying therapeutic targets. Emerging pieces of evidence from recent research in the field of ER stress have demonstrated a close association between unfolded protein response (UPR)-associated cellular activities and DR development. In this minireview article, we shall provide an emerging understating of how UPR influences DR pathogenesis at the cellular level.

Mechanisms Targeting the Unfolded Protein Response in Asthma

Lung cells are constantly exposed to various internal and external stressors that disrupt protein homeostasis. To cope with these stimuli, cells evoke a highly conserved adaptive mechanism called the unfolded protein response (UPR). UPR stressors can impose greater protein secretory demands on the endoplasmic reticulum (ER), resulting in the development, differentiation, and survival of these cell types to meet these increasing functional needs. Dysregulation of the UPR leads to the development of the disease. The UPR and ER stress are involved in several human conditions, such as chronic inflammation, neurodegeneration, metabolic syndrome, and cancer. Furthermore, potent and specific compounds that target the UPR pathway are under development as future therapies. The focus of this review is to thoroughly describe the effects of both internal and external stressors on the ER in asthma. Furthermore, we discuss how the UPR signaling pathway is activated in the lungs to overcome cellular damage. We also present an overview of the pathogenic mechanisms, with a brief focus on potential strategies for pharmacological interventions.

MiR-17-5p-mediated endoplasmic reticulum stress promotes acute myocardial ischemia injury through targeting Tsg101

Cardiovascular diseases are the leading cause of death globally, among which acute myocardial infarction (AMI) frequently occurs in the heart and proceeds from myocardium ischemia and endoplasmic reticulum (ER) stress-induced cell death. Numerous studies on miRNAs indicated their potential as diagnostic biomarkers and treatment targets for heart diseases. Our study investigated the role of miR-17-5p and its regulatory mechanisms during AMI. Echocardiography, MTT, flow cytometry assay, evaluation of caspase-3 and lactate dehydrogenase (LDH) activity were conducted to assess cell viability, apoptosis in an MI/R mice model, and an H2O2-induced H9c2 hypoxia cell model, respectively. The expression levels of ER stress response-related biomarkers were detected using qRT-PCR, IHC, and western blotting assays. The binding site of miR-17-5p on Tsg101 mRNA was determined by bioinformatic prediction and luciferase reporter assay. The expression levels of miR-17-5p were notably elevated in MI/R mice and hypoxia cell models, accompanied by enhanced cell apoptosis. Inhibition of miR-17-5p led to decreased apoptosis related to ER stress response in the hypoxia model, which could be counteracted by knockdown of Tsg101 (tumor susceptibility gene 101). Transfection with miR-17-5p mimics downregulated the expression of Tsg101 in H9c2 cells. Luciferase assay demonstrated the binding between miR-17-5p and Tsg101. Moreover, 4-PBA, the inhibitor of the ER stress response, abolished shTsg101 elevated apoptosis in hypoxic H9c2 cells. Our findings investigated the pro-apoptotic role of miR-17-5p during MI/R, disclosed the specific mechanism of miR-17-5p/Tsg101 regulatory axis in ER stress-induced myocardium injury and cardiomyocytes apoptosis, and presented a promising diagnostic biomarker and potential target for therapy of AMI.

Metabolic Dysregulation and Neurovascular Dysfunction in Diabetic Retinopathy

Diabetic retinopathy is a major cause of ocular complications in patients with type 1 and type 2 diabetes in developed countries. Due to the continued increase in the number of people with obesity and diabetes in the United States of America and globally, the incidence of diabetic retinopathy is expected to increase significantly in the coming years. Diabetic retinopathy is widely accepted as a combination of neurodegenerative and microvascular changes; however, which change occurs first is not yet understood. Although the pathogenesis of diabetic retinopathy is very complex, regulated by numerous signaling pathways and cellular processes, maintaining glucose homeostasis is still an essential component for normal physiological functioning of retinal cells. The maintenance of glucose homeostasis is finely regulated by coordinated interplay between glycolysis, Krebs cycle, and oxidative phosphorylation. Glycolysis is the most conserved metabolic pathway in biology and is tightly regulated to maintain a steady-state concentration of glycolytic intermediates; this regulation is called scheduled or regulated glycolysis. However, an abnormal increase in glycolytic flux generates large amounts of intermediate metabolites that can be shunted into different damaging pathways including the polyol pathway, hexosamine pathway, diacylglycerol-dependent activation of the protein kinase C pathway, and Amadori/advanced glycation end products (AGEs) pathway. In addition, disrupting the balance between glycolysis and oxidative phosphorylation leads to other biochemical and molecular changes observed in diabetic retinopathy including endoplasmic reticulum-mitochondria miscommunication and mitophagy dysregulation. This review will focus on how dysregulation of glycolysis contributes to diabetic retinopathy.

The Impact of Diabetes Mellitus in COVID-19: A Mechanistic Review of Molecular Interactions

The ongoing pandemic of COVID-19 is now the major issue in global health. Evidence implies that patients with diabetes are at a higher risk of severe disease or death due to COVID-19 than individuals without diabetes. However, the underlying mechanism for this differential effect in individuals with and without diabetes is not clearly understood. We have reviewed the pathophysiological pathways which may facilitate the entry of virus or an increase in its infectivity in host cells in the diabetic milieu. We suggest that the preexisting pathological pathways in patients with poorly controlled diabetes increase the risk of infectivity and are responsible for the higher levels of tissue injury and death in patients with diabetes.

Melatonin ameliorated CUMS-induced depression-like behavior via restoring endoplasmic reticulum stress in rat hippocampus

Melatonin is a hormone synthesized and secreted by the pineal gland with the effect of regulating sleep rhythm. Circadian and sleep disturbances may be central for understanding the pathophysiology and treatment of depression. Recently, the melatonergic system has been implicated in the pathophysiology and treatment of depression. In this study, we observed the effects of melatonin on depression-like behavior induced by chronic unpredictable mild stress (CUMS) in rats, and its molecular mechanism was explored. Adult male Sprague-Dawley rats were exposed to CUMS for 4 weeks. Melatonin or saline was injected intraperitoneally. Behavioral changes of Sprague-Dawley rats were detected by the open field test, sugar preference test, elevated O maze test and forced swimming test. In addition, the plasma corticosterone level and the expression of endoplasmic reticulum stress-related protein in the hippocampus of rats were measured. Compared with the control group, the CUMS-exposed Sprague-Dawley rats showed depression-like behavior, which was significantly improved by melatonin treatment. Moreover, CUMS induced endoplasmic reticulum stress and JNK phosphorylation in the hippocampus. Melatonin treatment could significantly reverse the endoplasmic reticulum stress and JNK phosphorylation induced by CUMS. These results suggest that melatonin improves depression-like behavior by inhibiting endoplasmic reticulum stress induced by CUMS. This study demonstrates that melatonin can improve depression-like behavior induced by CUMS, which may be related to the inhibition of endoplasmic reticulum stress and JNK phosphorylation in rat hippocampus.

Epithelial-mesenchymal transition of absorptive enterocytes and depletion of Peyer's patch M cells after PEDV infection

This study focused on intestinal restitution including phenotype switching of absorptive enterocytes and the abundance of different enterocyte subtypes in weaned pigs after porcine epidemic diarrhea virus (PEDV) infection. At 10 days post-PEDV-inoculation, the ratio of villus height to crypt depth in both jejunum and ileum had restored, and the PEDV antigen was not detectable. However, enterocytes at the villus tips revealed epithelial-mesenchymal transition (EMT) in the jejunum in which E-cadherin expression decreased while expression of N-cadherin, vimentin, and Snail increased. Additionally, there was reduced expression of actin in microvilli and Zonula occludens-1 (ZO-1) in tight junctions. Moreover, the protein concentration of transforming growth factor β1 (TGFβ1), which mediates EMT and cytoskeleton alteration, was increased. We also found a decreased number of Peyer's patch M cells in the ileum. These results reveal incomplete restitution of enterocytes in the jejunum and potentially impaired immune surveillance in the ileum after PEDV infection.

Nna1 gene deficiency triggers Purkinje neuron death by tubulin hyperglutamylation and ER dysfunction

Posttranslational glutamylation/deglutamylation balance in tubulins influences dendritic maturation and neuronal survival of cerebellar Purkinje neurons (PNs). PNs and some additional neuronal types degenerate in several spontaneous, independently occurring Purkinje cell degeneration (pcd) mice featuring mutant neuronal nuclear protein induced by axotomy (Nna1), a deglutamylase gene. This defective deglutamylase allows glutamylases to form hyperglutamylated tubulins. In pcd, all PNs die during postnatal “adolescence.” Neurons in some additional brain regions also die, mostly later than PNs. We show in laser capture microdissected single PNs, in cerebellar granule cell neuronal clusters, and in dissected hippocampus and substantia nigra that deglutamase mRNA and protein were virtually absent before pcd PNs degenerated, whereas glutaminase mRNA and protein remained normal. Hyperglutamylated microtubules and dimeric tubulins accumulated in pcd PNs and were involved in pcd PN death by glutamylase/deglutamylase imbalance. Importantly, treatment with a microtubule depolymerizer corrected the glutamylation/deglutamylation ratio, increasing PN survival. Further, before onset of neuronal death, pcd PNs displayed prominent basal polylisosomal masses rich in ER. We propose a “seesaw” metamorphic model summarizing mutant Nna1-induced tubulin hyperglutamylation, the pcd’s PN phenotype, and report that the neuronal disorder involved ER stress, unfolded protein response, and protein synthesis inhibition preceding PN death by apoptosis/necroptosis.

Purkinje cell degeneration is due to ER stress, unfolded protein response, and protein synthesis inhibition preceding Purkinje neuron death by apoptosis/necroptosis.

Computer-aided drug design against spike glycoprotein of SARS-CoV-2 to aid COVID-19 treatment

BACKGROUND

SARS-CoV-2 has the Spike glycoprotein (S) which is crucial in attachment with host receptor and cell entry leading to COVID-19 infection. The current study was conducted to explore drugs against Receptor Binding Domain (RBD) of SARS-CoV-2 using in silico pharmacophore modelling and virtual screening approach to combat COVID-19.

METHODS

All the available sequences of RBD in NCBI were retrieved and multiple aligned to get insight into its diversity. The 3D structure of RBD was modelled and the conserved region was used as a template to design pharmacophore using LigandScout. Lead compounds were screened using Cambridge, Drugbank, ZINC and TIMBLE databases and these identified lead compounds were screened for their toxicity and Lipinski's rule of five. Molecular docking of shortlisted lead compounds was performed using AutoDock Vina and interacting residues were visualized.

RESULTS

Active residues of Receptor Binding Motif (RBM) in S, involved in interaction with receptor, were found to be conserved in all 483 sequences. Using this RBM motif as a pharmacophore a total of 1327 lead compounds were predicted initially from all databases, however, only eight molecules fit the criteria for safe oral drugs. Conclusion: The RBM region of S interacts with Angiotensin Converting Enzyme 2 (ACE2) receptor and Glucose Regulated Protein 78 (GRP78) to mediate viral entry. Based on in silico analysis, the lead compounds scrutinized herewith interact with S, hence, can prevent its internalization in cell using ACE2 and GRP78 receptor.The compounds predicted in this study are based on rigorous computational analysis and the evaluation of predicted lead compounds can be promising in experimental studies.

Neuroinflammation in Primary Open-Angle Glaucoma

Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increasing evidence suggests oxidative damage and immune response defects are key factors contributing to glaucoma onset. Indeed, both the failure of the trabecular meshwork tissue in the conventional outflow pathway and the neuroinflammation process, which drives the neurodegeneration, seem to be linked to the age-related over-production of free radicals (i.e., mitochondrial dysfunction) and to oxidative stress-linked immunostimulatory signaling. Several previous studies have described a wide range of oxidative stress-related makers which are found in glaucomatous patients, including low levels of antioxidant defences, dysfunction/activation of glial cells, the activation of the NF-κB pathway and the up-regulation of pro-inflammatory cytokines, and so on. However, the intraocular pressure is still currently the only risk factor modifiable by medication or glaucoma surgery. This present review aims to summarize the multiple cellular processes, which promote different risk factors in glaucoma including aging, oxidative stress, trabecular meshwork defects, glial activation response, neurodegenerative insults, and the altered regulation of immune response.

Confirming whether novel rhein derivative 4a induces paraptosis-like cell death by endoplasmic reticulum stress in ovarian cancer cells

Ovarian cancer is the leading cause of death among gynecologic cancer patients. Although platinum-based chemotherapy as a frontline treatment for ovarian cancer has been widely used in clinical settings, its clinical efficacy is not satisfactory due to the resistance of ovarian cancer cells to apoptosis. Therefore, it is of great significance to induce non-apoptotic programed cell death patterns, such as paraptosis, in ovarian cancer. In this study, we aimed to explore the potential anticancer mechanisms of novel rhein derivative 4a, which was modified with rhein as a lead compound. The results showed that a wide range of vacuoles from the endoplasmic reticulum and mitochondria appeared in ovarian SKOV3, SKOV3-PM4, and A2780 cells treated with derivative 4a, and the cell death caused by derivative 4a is a type of non-apoptotic and non-autophagic death, which is caused by expansion and damage of the endoplasmic reticulum or mitochondria, showing the characteristics of para-apoptotic death. Furthermore, derivative 4a stimulated the unfolded protein reaction of ovarian cancer cells by upregulating the expression of Bip78 and activating the PERK-eIF2α-ATF4 pathways. Notably, rhein derivative 4a-induced cell death was positively correlated with activation of p38, ERK, and JNK, and negatively correlated with Alix, a known protein that inhibits paraptosis. In addition, derivative 4a treatment also induced G2/M phase arrest in ovarian cancer cells. Taken together, our study reveals that derivative 4a induces paraptosis, and this finding can serve as a basis in developing a new strategy for the treatment of antiapoptotic ovarian cancer.

Proteotoxic Stress and Cell Death in Cancer Cells

To maintain proteostasis, cells must integrate information and activities that supervise protein synthesis, protein folding, conformational stability, and also protein degradation. Extrinsic and intrinsic conditions can both impact normal proteostasis, causing the appearance of proteotoxic stress. Initially, proteotoxic stress elicits adaptive responses aimed at restoring proteostasis, allowing cells to survive the stress condition. However, if the proteostasis restoration fails, a permanent and sustained proteotoxic stress can be deleterious, and cell death ensues. Many cancer cells convive with high levels of proteotoxic stress, and this condition could be exploited from a therapeutic perspective. Understanding the cell death pathways engaged by proteotoxic stress is instrumental to better hijack the proliferative fate of cancer cells.

The Protective Effect of Luteolin in Glucocorticoid-Induced Osteonecrosis of the Femoral Head

Glucocorticoid-induced osteonecrosis of the femoral head (GIONFH) is a frequently occurring type of nontraumatic osteonecrosis. A failure of the timely treatment can eventually result in the collapse of the subchondral bone structure. Luteolin (Lut), a compound extracted from Rhizoma Drynariae, is reported to possess multiple pharmacological properties including anticancer, antioxidant, antiapoptosis, and antiinflammatory properties. However, whether Lut has a protective effect on the development of GIONFH remains unclear. In this study, we evaluated the effect of Lut on Dexamethasone (Dex)-induced STAT1/caspase3 pathway in vitro and evaluated GIONFH model in vivo. In vitro, Lut inhibited the upregulation of Dex-induced phospho-STAT1, cleaved caspase9, and cleaved caspase3. In addition, Lut inhibited Dex-induced expression of Bax and cytochrome c and increased the expression of B cell lymphoma-2(Bcl-2). In vivo, Lut decreased the proportion of empty lacunae in rats with GIONFH. Taken together, these findings indicate that Lut may have therapeutic potential in the treatment of GIONFH. Further, this effect might be achieved by suppressing mitochondrial apoptosis of osteoblasts via inhibition of STAT1 activity.

Nuclear Heme Oxidase-1 Inhibits Endoplasmic Reticulum Stress-Mediated Apoptosis after Spinal Cord Injury

The treatment goal for spinal cord injury (SCI) is to repair neurites and suppress cellular apoptosis. This study is to investigate the effects of nuclear heme oxidase-1 (HO-1) on the acute spinal cord injury and the related mechanisms. The rat model of the SCI was established. On day 7, before model establishment, the adenovirus vector carrying nuclear HO-1 (Ad-GFP-HO-1CΔ23) was injected into the animals into the tenth thoracic spine (T10) segment by the intrathecal injection. Starting from after the model establishment to day 28, the recovery of motor function was assessed by the Basso-Beattie-Bresnahan (BBB) scoring method. Immunofluorescence was performed to detect the expression patterns of nuclear and cytoplasmic proteins. HE and Nissl staining methods were used to evaluate the structural damage and the number of surviving neurons near the injured area. The TUNEL method was conducted to evaluate the apoptotic degree. Protein expression levels were detected with the Western blot analysis. The BBB assay scores in the nuclear HO-1 group were significantly higher than the blank and adenovirus control groups. Moreover, compared to the blank and adenovirus control groups, the neuronal apoptosis in the nuclear HO-1 group was significantly alleviated. Furthermore, the expression levels of the endoplasmic reticulum stress-related proteins, i.e., CHOP, GRP78, and caspase-12, were significantly decreased in the nuclear HO-1 group. Nuclear HO-1 significantly improves the SCI, promotes the functional recovery, inhibits the endoplasmic reticulum stress, and alleviates the apoptotic process after SCI.

Resveratrol synergizes with cisplatin in antineoplastic effects against AGS gastric cancer cells by inducing endoplasmic reticulum stress‑mediated apoptosis and G2/M phase arrest

Gastric cancer (GC) is a common gastrointestinal malignancy, and cisplatin (DDP) is an important component of chemotherapeutic regimens for GC. However, the application of DDP is limited by its dose-dependent systemic toxicity. Resveratrol (RES) is a natural polyphenol compound that has chemopreventive and therapeutic effects against various cancers, including GC. However, whether RES can sensitize GC cells to DDP remains unknown. Following RES/DDP combination treatment, cell viability was determined by Cell Counting Kit-8 and colony-forming assays, and cell apoptosis and the cell cycle were detected by FITC-Annexin V/PI staining assay and PI staining assay, respectively, followed by flow cytometry. Moreover, western blotting was performed to evaluate the protein expression levels, and the intracellular free Ca²⁺ concentration was determined by a Fluo-4 AM probe after cell cotreatment with RES and DDP. The present results demonstrated that RES/DDP combination treatment significantly inhibited cell viability, promoted cell apoptosis and induced G2/M phase arrest in AGS cells. In addition, it was determined that RES combined with DDP significantly increased the levels of Bax, cleaved poly-ADP-ribose polymerase (PARP), glucose-regulated protein 78 (GRP78), PRKR-like ER kinase (PERK), p-eukaryotic translation initiation factor 2α (p-eIF2α), CCAAT/enhancer binding protein homologous protein (CHOP) and cleaved caspase-12, whereas Bcl-2 expression was downregulated following RES/DDP cotreatment. Moreover, RES/DDP cotreatment significantly upregulated phosphorylated cyclin-dependent kinase 1 (p-CDK1, Tyr15), p21^Waf1/Cip1 and p27^Kip1 protein levels and downregulated Cdc25C protein levels. In conclusion, RES and DDP synergistically inhibited the growth of the gastric adenocarcinoma cell line AGS by inducing endoplasmic reticulum stress-mediated apoptosis and G2/M phase arrest via activation of the PERK/eIF2α/activating transcription factor 4 (ATF4)/CHOP signaling pathway and caspase-12 and by inactivating the CDK1-cyclin B1 complex. These results indicated that RES is a promising adjuvant for DDP during GC chemotherapy.

Ciclopirox activates PERK-dependent endoplasmic reticulum stress to drive cell death in colorectal cancer

Ciclopirox (CPX) modulates multiple cellular pathways involved in the growth of a variety of tumor cell types. However, the effects of CPX on colorectal cancer (CRC) and the underlying mechanisms for its antitumor activity remain unclear. Herein, we report that CPX exhibited strong antitumorigenic properties in CRC by inducing cell cycle arrest, repressing cell migration, and invasion by affecting N-cadherin, Snail, E-cadherin, MMP-2, and MMP-9 expression, and disruption of cellular bioenergetics contributed to CPX-associated inhibition of cell growth, migration, and invasion. Interestingly, CPX-induced reactive oxygen species (ROS) production and impaired mitochondrial respiration, whereas the capacity of glycolysis was increased. CPX (20 mg/kg, intraperitoneally) substantially inhibited CRC xenograft growth in vivo. Mechanistic studies revealed that the antitumor activity of CPX relies on apoptosis induced by ROS-mediated endoplasmic reticulum (ER) stress in both 5-FU-sensitive and -resistant CRC cells. Our data reveal a novel mechanism for CPX through the disruption of cellular bioenergetics and activating protein kinase RNA-like endoplasmic reticulum kinase (PERK)-dependent ER stress to drive cell death and overcome drug resistance in CRC, indicating that CPX could potentially be a novel chemotherapeutic for the treatment of CRC.

Phosphorylation within the bipartite NLS alters the localization and toxicity of the ER stress response factor DDIT3/CHOP

Regulated nuclear-cytoplasmic trafficking is a well-established mechanism utilized by cells to regulate adaptive and maladaptive responses to acute oxidant stress. Commonly associated with endoplasmic reticulum stress, the bZIP transcription factor CCAAT/enhancer-binding protein homologous protein (CHOP/DDIT3) mediates the cellular response to redox stress with effects on cellular growth, differentiation, and survival. We show through functional analyses that CHOP contains a conserved, compound pat4/bipartite nuclear localization signal within the basic DNA-binding domain. Using phylogenetic analyses and mass spectrometry, we now show that Ser107 located within the linker region of the bipartite NLS domain is a substrate for phosphorylation under standard culture conditions. Studies using the S107E phospho-mimic of CHOP indicate that changes in the charge properties at this residue regulate CHOP's nuclear-to-cytoplasmic ratio. And while co-stimulation with the SERCA inhibitor thapsigargin induced injury in cells expressing wild-type CHOP, the S107A point-mutant blocked this response. These findings indicate that phosphorylation within the bipartite NLS exerts regulatory effects on both the subcellular localization and toxic potential of DDIT3/CHOP. Future studies geared towards defining the relevant kinase/phosphatase networks that converge on the phosphorylation-regulated NLS (prNLS) phosphoepitope may provide an opportunity to constrain cellular damage in the context of acute ER stress.

Epigallocatechin-3-gallate (EGCG) protects the oocytes from methyl parathion-induced cytoplasmic deformities by suppressing oxidative and endoplasmic reticulum stress

Methyl parathion (MP) is a commonly used organophosphorus insecticide in commercial farming. It is well known that MP exposure can affect the function of nervous, respiratory, cardiovascular and reproductive systems. In our previous report we have demonstrated that MP exposure results in poor oocyte maturation and defective embryo development which is mainly mediated through oxidative stress. The present investigation was designed to explore whether using a potent free radical scavenger like Epigallocatechin-3-gallate (EGCG) can help in reducing the detrimental effects of MP on the oocytes. For the study, germinal vesicle (GV) stage oocytes collected from the ovaries of adult Swiss albino mice were subjected to in vitro maturation (IVM) in the presence or absence of MP (100 μg/mL) and/or EGCG (0.25 μM). MP significantly reduced the nuclear maturation rate, and resulted in poor cytoplasmic organization which was evident from the altered distribution pattern of mitochondria, endoplasmic reticulum and abnormal spindle organization. These changes were associated with significant elevation in oxidative stress and expression of ER stress markers such as 78 kDa Glucose regulated protein (GRP78) as well as X-box binding protein-1 (XBP1) in the oocytes. Further, the oocytes exposed to MP had lower activation rate and developmental potential. Supplementation of EGCG during IVM not only improved the nuclear maturation rate but also reduced the cytoplasmic abnormalities. These beneficial effects appear to be due to mitigation of oxidative and ER stress in oocytes. In conclusion, results of our study indicate that EGCG can help in alleviating MP-induced oocyte abnormalities.

Nobiletin in Cancer Therapy: How This Plant Derived-Natural Compound Targets Various Oncogene and Onco-Suppressor Pathways

Cancer therapy is a growing field, and annually, a high number of research is performed to develop novel antitumor drugs. Attempts to find new antitumor drugs continue, since cancer cells are able to acquire resistance to conventional drugs. Natural chemicals can be considered as promising candidates in the field of cancer therapy due to their multiple-targeting capability. The nobiletin (NOB) is a ubiquitous flavone isolated from Citrus fruits. The NOB has a variety of pharmacological activities, such as antidiabetes, antioxidant, anti-inflammatory, hepatoprotective, and neuroprotective. Among them, the antitumor activity of NOB has been under attention over recent years. In this review, we comprehensively describe the efficacy of NOB in cancer therapy. NOB induces apoptosis and cell cycle arrest in cancer cells. It can suppress migration and invasion of cancer cells via the inhibition of epithelial-to-mesenchymal transition (EMT) and EMT-related factors such as TGF-β, ZEB, Slug, and Snail. Besides, NOB inhibits oncogene factors such as STAT3, NF-κB, Akt, PI3K, Wnt, and so on. Noteworthy, onco-suppressor factors such as microRNA-7 and -200b undergo upregulation by NOB in cancer therapy. These onco-suppressor and oncogene pathways and mechanisms are discussed in this review.

The impact of proteostasis dysfunction secondary to environmental and genetic causes on neurodegenerative diseases progression and potential therapeutic intervention

Aggregation of particular proteins in the form of inclusion bodies or plaques followed by neuronal death is a hallmark of neurodegenerative proteopathies such as primary Parkinsonism, Alzheimer's disease, Lou Gehrig's disease, and Huntington's chorea. Complex polygenic and environmental factors implicated in these proteopathies. Accumulation of proteins in these disorders indicates a substantial disruption in protein homeostasis (proteostasis). Proteostasis or cellular proteome homeostasis is attained by the synchronization of a group of cellular mechanisms called the proteostasis network (PN), which is responsible for the stability of the proteome and achieves the equilibrium between synthesis, folding, and degradation of proteins. In this review, we will discuss the different types of PN and the impact of PN component dysfunction on the four major neurodegenerative diseases mentioned earlier. Graphical abstract.

Mechanism of inositol-requiring enzyme 1-alpha inhibition in endoplasmic reticulum stress and apoptosis in ovarian cancer cells

IRE1α endonuclease is a key regulator of endoplasmic reticulum (ER) stress that controls cell survival/apoptosis in cancers. Inhibition of IRE1α endonuclease leads to decreased splice XBP1 which decreases cell proliferation and increases cell death in cancer cells. Therefore, this study investigated the effects and mechanism of STF-083010 (an IRE1α inhibitor) on the cell growth/apoptosis of ovarian malignant cells via the XBP1-CHOP-Bim pathway following the induction of ER stress (ERS). ERS in OVCAR3 and SKOV3 cells was measured using Thioflavin T staining. The expression of ER stress response genes was evaluated by QRT-PCR. The levels of XBP1(s), PERK, phospho-PERK, p-PP2A, ATF4, BIP/GRP78, CHOP, and Bim proteins were evaluated using western blotting. Cell viability and apoptosis in STF-083010 and Tunicamycin (Tm) co-treated cells were assessed using BrdU, MTT, Annexin V-FITC/PI staining, and caspases-12 and -3 activity assays. The results showed increased XBP1, CHOP, and ATF-4 mRNA expression levels as well as high protein aggregation in STF-083010 and Tm co-treated cells. The IRE1α inhibitor down-regulated sXBP1 and BIP proteins, while XBP-1, p-PERK, ATF-4, CHOP, and Bim proteins were up-regulated. STF-083010 reduced cell proliferation and induced apoptosis through the activation of caspases-12 and -3 and Bax/Bcl-2 protein expression. In summary, the present data revealed the effects of STF-083010 in ER stress and apoptosis as well as signaling via XBP1/CHOP/Bim mediators. Thus, STF-083010 is proposed as a new target for the control of ERS in ovarian cancer cells.

Dexmedetomidine inhibits neuronal apoptosis by inducing Sigma-1 receptor signaling in cerebral ischemia-reperfusion injury

Dexmedetomidine is known to alleviate cerebral ischemia-reperfusion injury (CIRI). We established a rat model of CIRI, which exhibited higher neurological deficit scores and a greater number of apoptotic cells in the cerebral ischemic penumbra than controls. Dexmedetomidine reversed the neuronal apoptosis and improved neurological function in this model. We then examined Sigma-1 receptor (Sig-1R) expression on the endoplasmic reticulum (ER) in brain tissues at different reperfusion time points. Sig-1R expression increased with CIRI and decreased with increasing reperfusion times. After 24 hours of reperfusion, dexmedetomidine upregulated Sig-1R expression, and ER stress proteins (GRP78, CHOP, JNK and Caspase-3) were detected in brain tissues with Western blotting. Moreover, GRP78 expression followed a pattern similar to Sig-1R. Dexmedetomidine induced GRP78 expression but inhibited CHOP, Caspase-3 and phosphorylated-JNK expression in brain tissues. A Sig-1R-specific inhibitor reduced GRP78 expression and partially inhibited the upregulation of GRP78 by dexmedetomidine. The inhibitor also increased CHOP and Caspase-3 expression and partially reversed the inhibitory effects of dexmedetomidine on these pro-apoptotic ER stress proteins. These results suggest that dexmedetomidine at least partially inhibits ER stress-induced apoptosis by activating Sig-1R, thereby attenuating brain damage after 24 hours of ischemia-reperfusion.

CD146 T cells in lung cancer: its function, detection, and clinical implications as a biomarker and therapeutic target

CD146 alternatively called melanoma cell adhesion molecule (MCAM), is a biomarker and therapeutic target of clinical significance. It is found on different cells including the endothelial cells and lymphocytes which participate in heterotypic and homotypic ligand-receptor. This review concentrated on the CD146 expression T cells (or lymphocytes) centering on Treg in lung cancer. Here, we have also considered the vigorous investigation of CD146 mainly acknowledged new roles, essential mechanisms and clinical implications of CD146 in cancer. CD146 has progressively become a significant molecule, particularly recognized as a novel biomarker, prognosis and therapy for cancer. Hence, targeting CD146 expression by utilization of methanol extracts of Calotropis procera leaf may be useful for the treatment of carcinogenesis.

Prognostic significance of mRNA expression of CASPs in gastric cancer

Current studies suggest that the cysteinyl aspartate specific proteinase (caspase/CASP) family may be closely associated with apoptosis. Scientists have suggested that caspases may be a key to the development of more effective anti-cancer therapies. However, the prognostic value of CASP expression in gastric cancer (GC) remains unclear. Using a Kaplan-Meier plotter online database, the predictive prognostic significance of the expression of 12 CASPs genes (CASP1, CASP2, CASP3, CASP4, CASP5, CASP6, CASP7, CASP8, CASP9, CASP10, CASP12 and CASP14) to overall survival (OS) in different clinicopathological features, including Lauren classification, pathological stages, therapies employed and differentiation in gastric cancer patients was explored. The present study revealed that higher CASP1, 2, 3, 4, 5, 6, 7 and 8 mRNA expression was associated with better OS, whereas higher expression of CASP9, 10, 12 and 14 showed an unfavorable OS in all GC patients. Moreover, CASP1 to 8 were all associated with favorable OS in intestinal type and diffuse type classified by Lauren classification. Therefore, the results of the present study suggested that the CASP family may function as new prognostic indicators in GC and may be helpful in making treatment decisions.

A Review of Cardiovascular Toxicity of Microcystins

The mortality rate of cardiovascular diseases (CVD) in China is on the rise. The increasing burden of CVD in China has become a major public health problem. Cyanobacterial blooms have been recently considered a global environmental concern. Microcystins (MCs) are the secondary products of cyanobacteria metabolism and the most harmful cyanotoxin found in water bodies. Recent studies provide strong evidence of positive associations between MC exposure and cardiotoxicity, representing a threat to human cardiovascular health. This review focuses on the effects of MCs on the cardiovascular system and provides some evidence that CVD could be induced by MCs. We summarized the current knowledge of the cardiovascular toxicity of MCs, with regard to direct cardiovascular toxicity and indirect cardiovascular toxicity. Toxicity of MCs is mainly governed by the increasing level of reactive oxygen species (ROS), oxidative stress in mitochondria and endoplasmic reticulum, the inhibition activities of serine/threonine protein phosphatase 1 (PP1) and 2A (PP2A) and the destruction of cytoskeletons, which finally induce the occurrence of CVD. To protect human health from the threat of MCs, this paper also puts forward some directions for further research.

Involvement of Mitochondrial Dysfunction, Endoplasmic Reticulum Stress, and the PI3K/AKT/mTOR Pathway in Nobiletin-Induced Apoptosis of Human Bladder Cancer Cells

Nobiletin (NOB) is a polymethoxylated flavonoid isolated from citrus fruit peel that has been shown to possess anti-tumor, antithrombotic, antifungal, anti-inflammatory and anti-atherosclerotic activities. The main purpose of this study was to explore the potential of using NOB to induce apoptosis in human bladder cancer cells and study the underlying mechanism. Using an MTT assay, agarose gel electrophoresis, a wound-healing assay, flow cytometry, and western blot analysis, this study investigated the signaling pathways involved in NOB-induced apoptosis in BFTC human bladder cancer cells. Our results showed that NOB at concentrations of 60, 80, and 100 μM inhibited cell growth by 42%, 62%, and 80%, respectively. Cells treated with 60 μM NOB demonstrated increased DNA fragmentation, and flow cytometry analysis confirmed that the treatment caused late apoptotic cell death. Western blot analysis showed that mitochondrial dysfunction occurred in NOB-treated BFTC cells, leading to cytochrome C release into cytosol, activation of pro-apoptotic proteins (caspase-3, caspase-9, Bad, and Bax), and inhibition of anti-apoptotic proteins (Mcl-1, Bcl-xl, and Bcl-2). NOB-induced apoptosis was also mediated by regulating endoplasmic reticulum stress via the PERK/elF2α/ATF4/CHOP pathway, and downregulating the PI3K/AKT/mTOR pathway. Our results suggested that the cytotoxic and apoptotic effects of NOB on bladder cancer cells are associated with endoplasmic reticulum stress and mitochondrial dysfunction.

The neurotoxicity induced by engineered nanomaterials

Engineered nanomaterials (ENMs) have been widely used in various fields due to their novel physicochemical properties. However, the use of ENMs has led to an increased exposure in humans, and the safety of ENMs has attracted much attention. It is universally acknowledged that ENMs could enter the human body via different routes, eg, inhalation, skin contact, and intravenous injection. Studies have proven that ENMs can cross or bypass the blood-brain barrier and then access the central nervous system and cause neurotoxicity. Until now, diverse in vivo and in vitro models have been developed to evaluate the neurotoxicity of ENMs, and oxidative stress, inflammation, DNA damage, and cell death have been identified as being involved. However, due to various physicochemical properties of ENMs and diverse study models in existing studies, it remains challenging to establish the structure-activity relationship of nanomaterials in neurotoxicity. In this paper, we aimed to review current studies on ENM-induced neurotoxicity, with an emphasis on the molecular and cellular mechanisms involved. We hope to provide a rational material design strategy for ENMs when they are applied in biomedical or other engineering applications.

Ameliorative effects of nano-selenium against NiSO4-induced apoptosis in rat testes

Nickel (Ni) is a common environmental pollutant, which has toxic effects on reproductive system. Nowadays, nano-selenium (Nano-Se) has aroused great attention due to its unique antioxidant effect, excellent biological activities and low toxicity. The aim of this study was to explore the protective effects of Nano-Se on NiSO₄-induced testicular injury and apoptosis in rat testes. Nickel sulfate (NiSO₄) (5 mg/kg b.w.) was administered intraperitoneally and Nano-Se (0.5, 1, and 2 mg Se/kg b.w., respectively) was given by oral gavage in male Sprague-Dawley rats. Histological changes in the testes were determined by H&E staining. The terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and immunohistochemistry were performed to evaluate the apoptosis in testes. Expression levels of mitochondrial apoptosis-related genes and proteins were analyzed by RT-qPCR and Western blot. The results showed that Nano-Se improved lesions of testicular tissue induced by NiSO₄. Nano-Se significantly alleviated NiSO₄-induced apoptosis in rat testes, as well as significantly downregulated the Bak, cytochrome c, caspase-9 and caspase-3 and upregulated Bcl-2 expression levels, all of which were involved in mitochondria-mediated apoptosis. Altogether, we concluded that Nano-Se may potentially exert protective effects on NiSO₄-induced testicular injury and attenuate apoptosis, at least partly, via regulating mitochondrial apoptosis pathways in rat testes.

Flaccidoxide-13-Acetate-Induced Apoptosis in Human Bladder Cancer Cells is through Activation of p38/JNK, Mitochondrial Dysfunction, and Endoplasmic Reticulum Stress Regulated Pathway

Flaccidoxide-13-acetate, an active compound isolated from cultured-type soft coral Sinularia gibberosa, has been shown to have inhibitory effects against invasion and cell migration of RT4 and T24 human bladder cancer cells. In our study, we used an 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation assay, and flow cytometry to determine the mechanisms of the anti-tumor effect of flaccidoxide-13-acetate. The MTT and colony formation assays showed that the cytotoxic effect of flaccidoxide-13-acetate on T24 and RT4 cells was dose-dependent, and the number of colonies formed in the culture was reduced with increasing flaccidoxide-13-acetate concentration. Flow cytometry analysis revealed that flaccidoxide-13-acetate induced late apoptotic events in both cell lines. Additionally, we found that flaccidoxide-13-acetate treatment upregulated the expressions of cleaved caspase 3, cleaved caspase 9, Bax, and Bad, and down-regulated the expressions of Bcl-2, p-Bad, Bcl-x1, and Mcl-1. The results indicated that apoptotic events were mediated by mitochondrial dysfunction via the caspase-dependent pathway. Flaccidoxide-13-acetate also provoked endoplasmic reticulum (ER) stress and led to activation of the PERK-eIF2α-ATF6-CHOP pathway. Moreover, we examined the PI3K/AKT signal pathway, and found that the expressions of phosphorylated PI3K (p-PI3K) and AKT (p-AKT) were decreased with flaccidoxide-13-acetate concentrations. On the other hand, our results showed that the phosphorylated JNK and p38 were obviously activated. The results support the idea that flaccidoxide-13-acetate-induced apoptosis is mediated by mitochondrial dysfunction, ER stress, and activation of both the p38 and JNK pathways, and also relies on inhibition of PI3K/AKT signaling. These findings imply that flaccidoxide-13-acetate has potential in the development of chemotherapeutic agents for human bladder cancer.

Photoreceptor Survival Is Regulated by GSTO1-1 in the Degenerating Retina

Purpose

Glutathione-S-transferase omega 1-1 (GSTO1-1) is a cytosolic glutathione transferase enzyme, involved in glutathionylation, toll-like receptor signaling, and calcium channel regulation. GSTO1-1 dysregulation has been implicated in oxidative stress and inflammation, and contributes to the pathogenesis of several diseases and neurological disorders; however, its role in retinal degenerations is unknown. The aim of this study was to investigate the role of GSTO1-1 in modulating oxidative stress and consequent inflammation in the normal and degenerating retina.

Methods

The role of GSTO1-1 in retinal degenerations was explored by using Gsto1-/- mice in a model of retinal degeneration. The expression and localization of GSTO1-1 were investigated with immunohistochemistry and Western blot. Changes in the expression of inflammatory (Ccl2, Il-1β, and C3) and oxidative stress (Nox1, Sod2, Gpx3, Hmox1, Nrf2, and Nqo1) genes were investigated via quantitative real-time polymerase chain reaction. Retinal function in Gsto1-/- mice was investigated by using electroretinography.

Results

GSTO1-1 was localized to the inner segment of cone photoreceptors in the retina. Gsto1-/- photo-oxidative damage (PD) mice had decreased photoreceptor cell death as well as decreased expression of inflammatory (Ccl2, Il-1β, and C3) markers and oxidative stress marker Nqo1. Further, retinal function in the Gsto1-/- PD mice was increased as compared to wild-type PD mice.

Conclusions

These results indicate that GSTO1-1 is required for inflammatory-mediated photoreceptor death in retinal degenerations. Targeting GSTO1-1 may be a useful strategy to reduce oxidative stress and inflammation and ameliorate photoreceptor loss, slowing the progression of retinal degenerations.

Signaling pathways involved in regulating apoptosis induction in host cells upon PRRSV infection

Porcine reproductive and respiratory syndrome virus (PRRSV) is the etiologic agent of porcine reproductive and respiratory syndrome (PRRS), a devastating disease of swine that poses a serious threat to the swine industry worldwide. The induction of apoptosis in host cells is suggested to be the key cellular mechanism that contributes to the pathogenesis of PRRS. Various signaling pathways have been identified to be involved in regulating PRRSV-induced apoptosis. In this review, we summarize the potential signaling pathways that contribute to PRRSV-induced apoptosis, and propose the issues that need to be addressed in future studies for a better understanding of the molecular basis underlying the pathogenesis of PRRS.

Emerging Therapeutic Targets in Oncologic Photodynamic Therapy

Background:

Reactive oxygen species sustain tumorigenesis and cancer progression through deregulated redox signalling which also sensitizes cancer cells to therapy. Photodynamic therapy (PDT) is a promising anti-cancer therapy based on a provoked singlet oxygen burst, exhibiting a better toxicological profile than chemo- and radiotherapy. Important gaps in the knowledge on underlining molecular mechanisms impede on its translation towards clinical applications.

Aims and Methods:

The main objective of this review is to critically analyse the knowledge lately gained on therapeutic targets related to redox and inflammatory networks underlining PDT and its outcome in terms of cell death and resistance to therapy. Emerging therapeutic targets and pharmaceutical tools will be documented based on the identified molecular background of PDT.

Results:

Cellular responses and molecular networks in cancer cells exposed to the PDT-triggered singlet oxygen burst and the associated stresses are analysed using a systems medicine approach, addressing both cell death and repair mechanisms. In the context of immunogenic cell death, therapeutic tools for boosting anti-tumor immunity will be outlined. Finally, the transcription factor NRF2, which is a major coordinator of cytoprotective responses, is presented as a promising pharmacologic target for developing co-therapies designed to increase PDT efficacy.

Conclusion:

There is an urgent need to perform in-depth molecular investigations in the field of PDT and to correlate them with clinical data through a systems medicine approach for highlighting the complex biological signature of PDT. This will definitely guide translation of PDT to clinic and the development of new therapeutic strategies aimed at improving PDT.

Bio-Field Array: The Influence of Junction Mediating and Regulatory Protein Expression on Cytoskeletal Filament Behavior During Apoptosis in Triple-Negative Breast Cancer

Introduction:

The Bio-Field Array (BFA) is a device that generates a dielectrophoretic electromagnetic field (DEP-EMF) when placed in a hypotonic saline solution and a direct current (dc) of ~3 amperes is applied. Human triple-negative breast cancer (MDA-MB-231 cells) is known to have a high percentage of apoptotic (P53) deficient cells and some patients can have poor outcomes with current treatments.

Objectives:

Previously, we reported a strong upregulation of the apoptotic arm of the unfolded protein response, via reverse transcription–quantitative polymerase chain reaction (RT-qPCR), as well as positive annexin staining in this human breast carcinoma, when grown in media prepared with BFA’s dc DEP-EMF treated saline. Here we will examine and discuss cytoskeletal microtubule changes that were noted in the treated breast carcinoma that are strongly suggestive of apoptosis and the possible correlation of these microtubule changes to the upregulation of Junction Mediating and Regulatory Protein (JMY, a P53/TP53 cofactor) that is known to drive cytoskeleton microfilaments (actin) function.

Methods:

In addition to microarray and RT-qPCR analyses, we conducted 7 days of fluorescent microscopic analyses of tubulin assays in these treated versus control MDA-MB-231 cells.

Results:

These data suggest 2 possible forms of apoptosis, rounded and irregular, may be occurring and possibly facilitated by the significant upregulation (via microarray and RT-qPCR) of an important but poorly understood Nucleation-Promoting Factor (NPF), JMY.

Conclusions:

The ability of the BFA dc DEP-EMF to significantly upregulate JMY and possibly influence the regulation of unbranched (nucleation-microtubule spikes) and branched forms (autophagy) of actin in the cytoplasmic domains may facilitate a “two coffins” or round and irregular necrosis-like apoptosis for this highly aggressive and often apoptotic-deficient breast cancer cell line.

Protective effect of Barbaloin in a rat model of myocardial ischemia reperfusion injury through the regulation of the CNPY2‑PERK pathway

Barbaloin (Bar) has a myocardial protective effect, but its mechanism of action is uncertain. The endoplasmic reticulum stress (ERS)-mediated apoptosis pathway serves an important role in the pathogenesis of myocardial ischemia-reperfusion injury (MIRI). Inhibiting ERS may significantly improve the progression of MIRI and serve a role in its prevention. Therefore, based on current knowledge of ERS-mediated cardiomyocyte apoptosis and the cardioprotective effect of Bar, the purpose of the present study was to further evaluate the myocardial protective effect and potential mechanisms of Bar pretreatment in MIRI. The present study established a MIR rat model and randomly divided these rats into four groups. Prior to myocardial ischemia, Bar (20 mg/kg) was administered to rats once daily for 1 week. Myocardial blood serum lactate dehydrogenase and creatine kinase were subsequently measured. A terminal deoxynucleotidyl transferase mediated dUTP nick end labeling assay was used to evaluate the myocardial protective effect of Bar pretreatment on MIRI. To assess whether the ERS signaling pathway was involved in the myocardial protection mechanism of Bar pretreatment, the expression levels of ERS-associated proteins, protein canopy homolog 2 (CNPY2), glucose regulatory protein 78, transcriptional activator 4, C/EBP-homologous protein (CHOP), PKR endoplasmic reticulum kinase (PERK), caspase-12 and caspase-3 were detected by western blot analysis, immunohistochemistry or reverse transcription-quantitative polymerase chain reaction. The results confirmed that Bar pretreatment significantly reduced the damage and the level of apoptosis caused by MIR. Bar pretreatment significantly inhibited the expression of ERS-associated proteins in cardiomyocytes. In addition, the immunohistochemistry results demonstrated that Bar pretreatment significantly inhibited the CNPY2-positive cell apoptosis ratio of cardiomyocytes. Therefore, the results of the current study suggested that CNPY2 is present in cardiomyocytes and participates in the development of MIRI by initiating the PERK-CHOP signaling pathway. Bar pretreatment may attenuate MIRI by inhibiting the CNPY2-PERK apoptotic pathway.

Cellular and Molecular Mechanism of Ganoderma (Lingzhi) Against Tumor

The anticancer potential of Ganoderma (Lingzhi) and its extracts has been widely demonstrated, including antiproliferative and apoptosis inductive, antimetastatic, antiangiogenic, and multidrug resistance reversional activities, involving a variety of cellular and molecular mechanisms besides antitumor immunology. Intrinsic- and extrinsic-initiated apoptotic pathway in association with cell cycle arresting, telomerase inhibiting, autophagy, and oxidative stress is involved in the antiproliferative and apoptosis inductive activities of Ganoderma and its extracts. The inhibition of tumor cell adhesion, invasion, and migration by Ganoderma and its extracts involves molecular mechanisms such as AP-1, NF-κB, MMP, cadherin, β-integrin, c-Met, FAK, EMT, and so on. Targeting the major pro-angiogenic stimulus, VEGF, and its receptor contributes to the inhibition of tumor angiogenesis by Ganoderma and its extracts. Inhibition against the ATP-dependent transmembrane drug transporter such as P-glycoprotein (P-gp) on the surface of resistant tumor cells to prevent reduction of the intracellular accumulation of anticancer drugs by pumping out the drugs plays an important role in the activities of Ganoderma and its extracts to reverse tumor cell multidrug resistance.

Visual Defects and Ageing

Many diseases are related to age, among these neurodegeneration is particularly important. Alzheimer's disease Parkinson's and Glaucoma have many common pathogenic events including oxidative damage, Mitochondrial dysfunction, endothelial alterations and changes in the visual field. These are well known in the case of glaucoma, less in the case of neurodegeneration of the brain. Many other molecular aspects are common, such as the role of endoplasmic reticulum autophagy and neuronal apoptosis while others have been neglected due to lack of space such as inflammatory cytokine or miRNA. Moreover, the loss of specific neuronal populations, the induction of similar mechanisms of cell injury and the deposition of protein aggregates in specific anatomical areas are very similar events between these diseases. Intracellular and/or extracellular accumulation of protein aggregates is a key feature of many neurodegenerative disorders. The existence of abnormal protein aggregates has been documented in the RGCs of glaucomatous patients such as the anomalous Tau protein or the β-amyloid accumulations. Intra-cell catabolic processes also appear to be common in both glaucoma and neurodegeneration. They also help us to understand how the basis between these diseases is common and how the visual aspects can be a serious problem for those who are affected.

Endoplasmic reticulum targeted cyclometalated iridium(iii) complexes as efficient photodynamic therapy photosensitizers

A series of ER-targeted cyclometalated Ir(iii) complexes with a gradually extended conjugated area in the main ligand were effective PDT photosensitizers and triggered ER-stress induced apoptosis in cancer cell lines.