Eukaryotic Initiation Factor 2alpha Research Articles

“Investigation of the potential cellular changes induced by magnesium sulfate and salubrinal in a lipopolysaccharide-induced chorioamnionitis model”

Chorioamnionitis is closely associated with preterm labor and poses a significant public health concern. In this pathological process where inflammation plays a key role, intracellular mechanisms such as endoplasmic reticulum stress are crucial. In this study, we aimed to explore the potential positive outcomes of the combined use of salubrinal (SLB) with magnesium (Mg) treatment in chorioamnionitis.Thirty pregnant rats were divided into 5 groups as: Control, LPS (1 mg/kg), LPS + SLB (1 mg/kg), LPS + Mg (Dhaka protocol), LPS + SLB + Mg. Rats were sacrificed 4 h after LPS administration, then placental and fetal brain tissues were collected.LPS administration enhanced the levels of tumor necrosis factor-alpha, vascular endothelial growth factor, caspase-3 immunoexpressions, BAX, eukaryotic initiation factor 2-alpha, s100, and glial fibrillary acidic protein expressions and lowered BCL2 expressions in the placenta or fetal brains. SLB and Mg treatments were observed to reverse all these findings, and the most significant positive effect was in the LPS + SLB + Mg group.The known anti-inflammatory activity of Mg, when used with SLB, preventing the transition to apoptosis and increasing antioxidant enzyme activity, as identified in this study, can contribute significantly to the literature. However, these results need to be supported by additional molecular studies.

Dysregulated RNA editing of EIF2AK2 in polycystic ovary syndrome: clinical relevance and functional implications

BackgroundPolycystic ovary syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive ages. Our previous study has implicated a possible link between RNA editing and PCOS, yet the actual role of RNA editing, its association with clinical features, and the underlying mechanisms remain unclear.MethodsTen RNA-Seq datasets containing 269 samples of multiple tissue types, including granulosa cells, T helper cells, placenta, oocyte, endometrial stromal cells, endometrium, and adipose tissues, were retrieved from public databases. Peripheral blood samples were collected from twelve PCOS and ten controls and subjected to RNA-Seq. Transcriptome-wide RNA-Seq data analysis was conducted to identify differential RNA editing (DRE) between PCOS and controls. The functional significance of DRE was evaluated by luciferase reporter assays and overexpression in human HEK293T cells. Dehydroepiandrosterone and lipopolysaccharide were used to stimulate human KGN granulosa cells to evaluate gene expression.ResultsRNA editing dysregulations across multiple tissues were found to be associated with PCOS in public datasets. Peripheral blood transcriptome analysis revealed 798 DRE events associated with PCOS. Through weighted gene co-expression network analysis, our results revealed a set of hub DRE events in PCOS blood. A DRE event in the eukaryotic translation initiation factor 2-alpha kinase 2 (EIF2AK2:chr2:37,100,559) was associated with PCOS clinical features such as luteinizing hormone (LH) and the ratio of LH over follicle-stimulating hormone. Luciferase assays, overexpression, and knockout of RNA editing enzyme adenosine deaminase RNA specific (ADAR) showed that the ADAR-mediated editing cis-regulated EIF2AK2 expression. EIAF2AK2 showed a higher expression after dehydroepiandrosterone and lipopolysaccharide stimulation, triggering changes in the downstrean MAPK pathway.ConclusionsOur study presented the first evidence of cross-tissue RNA editing dysregulation in PCOS and its clinical associations. The dysregulation of RNA editing mediated by ADAR and the disrupted target EIF2AK2 may contribute to PCOS development via the MPAK pathway, underlining such epigenetic mechanisms in the disease.

Protein Kinases in Obesity, and the Kinase-Targeted Therapy.

The action of protein kinases and protein phosphatases is essential for multiple physiological responses. Each protein kinase displays its own unique substrate specificity and a regulatory mechanism that may be modulated by association with other proteins. Protein kinases are classified as dual-specificity kinases and dual-specificity phosphatases. Dual-specificity phosphatases are important signal transduction enzymes that regulate various cellular processes in coordination with protein kinases and play an important role in obesity. Impairment of insulin signaling in obesity is largely mediated by the activation of the inhibitor of kappa B-kinase beta and the c-Jun N-terminal kinase (JNK). Oxidative stress and endoplasmic reticulum (ER) stress activate the JNK pathway which suppresses insulin biosynthesis. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) are important for proper regulation of glucose metabolism in mammals at both the hormonal and cellular levels. Additionally, obesity-activated calcium/calmodulin dependent-protein kinase II/p38 suppresses insulin-induced protein kinase B phosphorylation by activating the ER stress effector, activating transcription factor-4. To alleviate lipotoxicity and insulin resistance, promising targets are pharmacologically inhibited. Nifedipine, calcium channel blocker, stimulates lipogenesis and adipogenesis by downregulating AMPK and upregulating mTOR, which thereby enhances lipid storage. Contrary to the nifedipine, metformin activates AMPK, increases fatty acid oxidation, suppresses fatty acid synthesis and deposition, and thus alleviates lipotoxicity. Obese adults with vascular endothelial dysfunction have greater endothelial cells activation of unfolded protein response stress sensors, RNA-dependent protein kinase-like ER eukaryotic initiation factor-2 alpha kinase (PERK), and activating transcription factor-6. The transcriptional regulation of adipogenesis in obesity is influenced by AGC (protein kinase A (PKA), PKG, PKC) family signaling kinases. Obesity may induce systemic oxidative stress and increase reactive oxygen species in adipocytes. An increase in intracellular oxidative stress can promote PKC-β activation. Activated PKC-β induces growth factor adapter Shc phosphorylation. Shc-generated peroxides reduce mitochondrial oxygen consumption and enhance triglyceride accumulation and lipotoxicity. Liraglutide attenuates mitochondrial dysfunction and reactive oxygen species generation. Co-treatment of antiobesity and antidiabetic herbal compound, berberine with antipsychotic drug olanzapine decreases the accumulation of triglyceride. While low-dose rapamycin, metformin, amlexanox, thiazolidinediones, and saroglitazar protect against insulin resistance, glucagon-like peptide-1 analog liraglutide inhibits palmitate-induced inflammation by suppressing mTOR complex 1 (mTORC1) activity and protects against lipotoxicity.

The PPP1R15 Family of eIF2-alpha Phosphatase Targeting Subunits (GADD34 and CReP).

The vertebrate PPP1R15 family consists of the proteins GADD34 (growth arrest and DNA damage-inducible protein 34, the product of the PPP1R15A gene) and CReP (constitutive repressor of eIF2α phosphorylation, the product of the PPP1R15B gene), both of which function as targeting/regulatory subunits for protein phosphatase 1 (PP1) by regulating subcellular localization, modulating substrate specificity and assembling complexes with target proteins. The primary cellular function of these proteins is to facilitate the dephosphorylation of eukaryotic initiation factor 2-alpha (eIF2α) by PP1 during cell stress. In this review, we will provide a comprehensive overview of the cellular function, biochemistry and pharmacology of GADD34 and CReP, starting with a brief introduction of eIF2α phosphorylation via the integrated protein response (ISR). We discuss the roles GADD34 and CReP play as feedback inhibitors of the unfolded protein response (UPR) and highlight the critical function they serve as inhibitors of the PERK-dependent branch, which is particularly important since it can mediate cell survival or cell death, depending on how long the stressful stimuli lasts, and GADD34 and CReP play key roles in fine-tuning this cellular decision. We briefly discuss the roles of GADD34 and CReP homologs in model systems and then focus on what we have learned about their function from knockout mice and human patients, followed by a brief review of several diseases in which GADD34 and CReP have been implicated, including cancer, diabetes and especially neurodegenerative disease. Because of the potential importance of GADD34 and CReP in aspects of human health and disease, we will discuss several pharmacological inhibitors of GADD34 and/or CReP that show promise as treatments and the controversies as to their mechanism of action. This review will finish with a discussion of the biochemical properties of GADD34 and CReP, their regulation and the additional interacting partners that may provide insight into the roles these proteins may play in other cellular pathways. We will conclude with a brief outline of critical areas for future study.

Increased endoplasmic reticulum stress might be related to brain damage in hepatic ischemia-reperfusion injury

Abstract Objectives Our study aimed to investigate the role of endoplasmic reticulum stress (ER) in brain damage following hepatic ischemia-reperfusion (HIR) injury. Specifically, we characterized the expression of markers of ER stress and histopathologic changes in the brain following HIR. Methods Twelve adults female Wistar rats were divided into two experimental groups equally. Group 1 was designed as the control group, and Group 2 was designed as the HIR group. Blood, liver, and brain tissue samples were collected during the sacrifice. The quantitative ELISA kits were used to detect glucose-regulated protein 78 (GRP-78), activating transcription factor 4 (ATF-4), eukaryotic initiation factor 2 alpha (EIF2-A), caspase-3, caspase-9, and CCAAT/enhancer-binding protein (CEBP) in plasma. Histopathological examination was performed for liver and brain tissues. Results Higher levels of GRP-78 (p=0.006), ATF4 (p=0.001), and EIF2-Α (p=0.007) were detected in group 2. More damage was detected in liver and brain samples in the histopathological examination of group 2 than in group 1. Conclusions Our results demonstrate that ER stress is involved in developing brain damage following hepatic ischemia-reperfusion injury, as evidenced by increased expression of markers of ER stress and neuronal injury.

Abstract P2-16-05: Targeting EZH2 to overcome chemoresistance in Triple Negative Breast Cancers Employing Combinatorial Approach

Abstract Objective: Triple Negative Breast Cancers (TNBC) are highly invasive and 46% of patients develop distant metastases, leading to higher mortality. Chemotherapy remains the most efficacious option, however, there is still a largely unmet need to identify novel therapeutic targets in TNBC to increase treatment options and improve patient outcomes, survival. Enhancer of zeste homologue 2 (EZH2), a member of the catalytic subunit of the polycomb repressive complex 2, is a histone methyltransferase and its canonical function is to methylate lysine 27 of histone 3. EZH2 is a potential driver of TNBC metastasis, and its high expression strongly associates with the TNBC phenotype as compared with other molecular subtypes of breast cancer. Despite the advancement in the discovery of inhibitors for EZH2 that attenuate its catalytic activity. Currently, several EZH2 inhibitors are under development and undergoing clinical trials and these compounds have been proved to be effective in the treatment of hematological malignancies, sarcomas and malignant rhabdoid tumors. However these inhibitors do not affect the intrinsic protein stability of EZH2, but typically competes with the cofactor S-adenosylmethionine (SAM) and binds to the SET domain of EZH2. Hence, the EZH2 inhibitors are only effective for some malignant blood tumors, and have poor efficacy for solid tumors, such as TNBC. Several studies have shown the involvement of neurotransmitter dopamine in proliferation, apoptosis, tumor angiogenesis, and drug resistance among different cancers, including the breast1. Dopamine D1 receptor activation in TNBC cell line induces apoptosis, autophagy and phosphorylation of eukaryotic translation initiation factor 2-alpha (eIF2a)2. Also, D1R agonists inhibits the invasion of breast cancer cell lines MDA-MB-231 and BT-20 and regress mammary tumors3. The oncogenic nature of EZH2 in driving aggressiveness in TNBC cells led us to simultaneously target dopamine D1 receptor and EZH2 to completely ablate tumor growth and metastasis. Methods: Schrodinger protein modeling software was employed for docking studies. TNBC cells MDA-MB-231 cells were treated with the EZH2 inhibitor GSK126 and/or D1R agonists A77636 and SKF38393 for assessing cell viability, migration. Immuno precipitation to investigate if the combination could disrupt the PRC2 complex in TNBC cells. To model tumor burden and the effects of combination therapy on tumor growth in vitro, we tested the combinatory effect of GSK126 and D1R agonists in a 3D culture system of MDA-MB-231 cells encapsulated in calcium-alginate microgels seeded from a microfluidic droplet generator. Cell death was determined by Yo-pro-Propidium Iodide staining. Result: In silico analysis confirmed that D1R agonists exhibited strong stabilization of protein structures upon binding to the EZH2 catalytic active site, albeit with slightly weaker affinity than GSK126. Combination treatment with GSK126 and dopamine agonists A77636 or SKF 38393 led to significant and synergistic inhibition of cell viability (p< 0.01), migration, invasion, and EZH2 activity (p< 0.01) in TNBC cells. In addition, MDA-MB-231 cells formed tumor spheroids that were subjected to the EZH2 inhibitor alongside dopamine agonists, indicating tumor reduction relative to single agent treatment in 3D culture (p < 0.0001). The combination also led to increased necrotic cell death (p < 0.05). Immunoprecipitation of EZH2 in the presence of GSK126 and SKF38393 and A77636 dissociated the physical interaction between EZH2, EED, and SUZ12 in MDA-MB-231 cells. Conclusion: Our data suggest that the combination of GSK126 and Dopamine D1 agonists synergistically inhibits TNBC proliferation by disrupting EZH2 functions leading to necrotic cell death. (This work is supported by DOD: W81XWH2010065, for Eswar Shankar). 1) PMID: 21531818 2) PMID: 29773888 3) PMID: 26477316 Citation Format: Eswar Shankar, Sridhar SNC, Xilal Y. Rima, Prem Kushwaha, Shiv Verma, Gautam K. Sarathy, Anagh kulkarni, Dharmaraja Allimuthu, Eduardo Reátegui, Sanjay Gupta, Bhuvaneswari Ramaswamy. Targeting EZH2 to overcome chemoresistance in Triple Negative Breast Cancers Employing Combinatorial Approach. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-16-05.

A CASE REPORT ON WOLCOTT RALLISON SYNDROME

A Case Report of Wolcott–Rallison syndrome, it is a rare, autosomal recessive disorder with infancy-onset diabetes mellitus, multiple epiphyseal dysplasia, osteopenia, mental retardation or developmental delay, and hepatic and renal dysfunction as main clinical findings. Patients have most common history of consanguineous marriage. Patients with WRS have mutations in the EIF2AK3 gene, which encodes the eukaryotic translation initiation factor 2-alpha kinase 3. Most common cause of death is fulminant hepatitis in early childhood.The EIKF2AK3 gene codes for PERK (pancreatic endoplasmic reticulum kinase),an explanation for the spectrum of symptoms.PERK is associated with the activity of beta cells in the pancreas.A broad range of bodily systems is affected, including pancreas, kidney, liver,bone, and nervous system, because of deficient stress response to improperly folded proteins inside the endoplasmic reticulum. A two months old male child born out of non-consanguineous marriage, Hindu by religion, presented with complain of fever since 4 days, respiratory distress since 12 hours. Patient was admitted and on regular blood sugar screening on arrival was high. Repeat random blood sugar was also elevated.Arterial blood gas was done which was suggested metabolic acidosis.Due to persistent high blood sugar,insulin drip was started and HbA1c was done which was 11 gm% and other investigations done. Diagnosis of neonatal diabetes mellitus was kept and managed accordingly. Studies for other endocrinopathies and autoimmune disease done which was negative. Child was having normal growth and development according to age. Genetic studies for neonatal diabetes was planned and EIKF2AK3 gene mutation was found homozygous. Both the parents were heterozygous for the mutation. So diagnosis was kept and regular follow up was advised.Key-words:Infant,Neonatal Diabetes,Endocrinopathy

Protective Effect of Sodium Hydrosulfide on Lipopolysaccharide Induced Myocardial Cell Injury Model: Involvement of Oxidative Stress and Endoplasmic Reticulum Stress

Lipopolysaccharide can induce myocardial cell injury, which has been widely used in the preparation of septic cardiomyopathy models. We herein aimed to evaluate the protective effects of sodium hydrosulfide against oxidative stress and endoplasmic reticulum stress on the cell model of septic cardiomyopathy and to explore whether the protein kinase RNA-like endoplasmic reticulum kinase-eukaryotic initiation factor 2 alpha signaling pathways was involved. The sepsis induced cardiomyopathy model which was established by inducing rat cardiomyoblast cell line H9c2 cells with lipopolysaccharide and sodium hydrosulfide and endogenous hydrogen sulfide inhibitor (DL-propargylglycine) were used for intervention treatment. Then, cell viability, endogenous hydrogen sulfide levels, lactate dehydrogenase, reactive oxygen species, superoxide dismutase, glutathione and malondialdehyde were determined using commercial assay kits; enzyme-linked immunosorbent assay was used to determine creatine kinase-myoglobin binding, interleukin-6, tumor necrosis factor alpha and interleukin-10; reverse transcription-polymerase chain reaction was used to determine cystathionine gamma-lyase messenger RNA expression; and Western blot was used to determine glucose-regulated protein 78, protein kinase RNA-like endoplasmic reticulum kinase, phosphorylated protein kinase RNA-like endoplasmic reticulum kinase, eukaryotic initiation factor alpha, phosphorylated eukaryotic initiation factor alpha, activating transcription factor 4 and C/EBP-homologous protein levels. Sodium hydrosulfide increased the hydrogen sulfide contents of cells, but did not affect the messenger RNA expression of cystathionine gamma-lyase. It attenuated the decrease in cell viability caused by lipopolysaccharide; reduced the release of the myocardial enzymes like lactate dehydrogenase and creatine kinase-myoglobin binding; reduced the level of inflammatory factors like interleukin-6 and tumor necrosis factor alpha; reduced the level of oxidative stress; inhibited the expression of protein kinase RNA-like endoplasmic reticulum kinase pathway proteins. Sodium hydrosulfide treatment improves septic cardiomyopathy by inhibiting oxidative stress and endoplasmic reticulum stress via the protein kinase RNA-like endoplasmic reticulum kinaseeukaryotic initiation factor alpha pathway, which may be a theory for the treatment of septic cardiomyopathy.

Platycodin D restores the intestinal mechanicalbarrier by reducing endoplasmic reticulum stress-mediated apoptosis

• Exploring the regulatory effect of PD on CP-induced intestinal injury. • Demonstrating that PD exerts a certain protective effect on intestinal damage caused by CP. • Revealing that PD for alleviating CP-induced intestinal damage might be related to PERK-eIF2ɑ-ATF4 signaling pathway. The current study aimed to reveal the inhibitory effect of Platycodin D (PD) on intestinal cell apoptosis mediated by ER stress. Treatment with PD alleviated pathological changes of the intestine and reduced secretion of intracellular enzyme Diamine oxidase (DAO) in the upper villi of the small intestinal mucosa in Cisplatin (CP) intestinal injury model and increased expression of key protein Occludin and ZO-1 of the intestinal mechanical barrier. PD inhibited ER stress in a dose-dependent in CP-caused IEC-6 cells and the level of phosphorylation of Protein kinase R-like ERK kinase (PERK) and Eukaryotic initiation factor-2 alpha (eIF2α) reduced. Besides, the ER stress inhibitor 4-PBA was used to confirm that PD alleviated the ER stress in vitro . In conclusion, PD exerted an intestinal protective effect through the inhibition of ER stress in CP-treated mice and IEC-6 cells. These data indicated that PD was a promising natural medicine for intestinal protection.

BRCA1 mediates protein homeostasis through the ubiquitination of PERK and IRE1.

Tumors with BRCA1 mutations have poor prognoses due to genomic instability. Yet this genomic instability has risks and BRCA1-deficient (def) cancer cells must develop pathways to mitigate these risks. One such risk is the accumulation of unfolded proteins in BRCA1-def cancers from increased mutations due to their loss of genomic integrity. Little is known about how BRCA1-def cancers survive their genomic instability. Here we show that BRCA1 is an E3 ligase in the endoplasmic reticulum (ER) that targets the unfolded protein response (UPR) stress sensors, Eukaryotic Translation Initiation Factor 2-alpha Kinase 3 (PERK) and Serine/Threonine-Protein Kinase/Endoribonuclease Inositol-Requiring Enzyme 1 (IRE1) for ubiquitination and subsequent proteasome-mediated degradation. When BRCA1 is mutated or depleted, both PERK and IRE1 protein levels are increased, resulting in a constitutively activated UPR. Furthermore, the inhibition of protein folding or UPR signaling markedly decreases the overall survival of BRCA1-def cancer cells. Our findings define a mechanism used by the BRCA1-def cancer cells to survive their increased unfolded protein burden which can be used to develop new therapeutic strategies to treat these cancers.

Wolcott Rallison Syndrome

Background: Wolcott–Rallison Syndrome (WRS) is a rare autosomal recessive disorder characterized by permanent neonatal diabetes mellitus, skeletal dysplasia, hepatic dysfunction, and other systemic associations. Clinical Description: A 3-month-old infant with a history of fever and poor oral intake presented with severe dehydration, acidosis and 3+ urine ketones and was diagnosed to have sepsis and diabetic ketoacidosis (DKA). He also developed acute kidney injury (AKI) with blood urea 118 mg/dL and serum creatinine 1.5 mg/dL. Management: The child was ventilated, stabilized, and managed for DKA with fluids and insulin as per guidelines. AKI was managed with peritoneal dialysis. Genetic analysis revealed homozygous mutation in eukaryotic translation initiation factor 2-alpha kinase 3 gene consistent with the diagnosis of WRS. A close follow-up was kept with regular screening for other associated manifestations. Central hypothyroidism was detected first followed by skeletal dysplasia and chronic kidney disease. Growth retardation and developmental delay are also present. Conclusion: Neonatal diabetes cases need an early genetic work up and watchful follow-up for the manifestation of other possible associated features.

The HMGB1-RAGE axis induces apoptosis in acute respiratory distress syndrome through PERK/eIF2α/ATF4-mediated endoplasmic reticulum stress.

Apoptosis plays a major role in the progression of acute respiratory distress syndrome (ARDS) that may involve the interaction of the high mobility group box 1 (HMGB1) protein with the receptor for advanced glycation end products (RAGE). However, the underlying mechanism remains unclear. Thus, we aimed to explore the mechanisms of HMGB1-RAGE axis-induced apoptosis in ARDS. Blood samples from ARDS patients and healthy volunteers were collected to investigate the correlation between serum HMGB1 levels and the severity of ARDS in patients. Mouse models of ARDS induced by caecal ligation and perforation and A549 cell models established by stimulation with recombinant human HMGB1 (rHMGB1) were designed to explore lung inflammatory injury and apoptosis. Serum HMGB1 levels were significantly increased in ARDS patients compared to controls, and HMGB1 levels in the Severe group and Nonsurvival group were significantly higher than those in the Mild and Moderate group and Survival group. In vivo, compared to sham mice, ARDS mice showed significant lung inflammatory injury and apoptosis as well as upregulation of HMGB1 and RAGE and endoplasmic reticulum stress (ERs) protein expression. All injury was attenuated by treatment with an HMGB1 inhibitor GA, a RAGE blocker FPS-ZM1, and an ERs inhibitor 4-PBA. In vitro, A549 cells challenged with rHMGB1 exhibited significant increases in the levels of proteins in the RNA-like endoplasmic reticulum kinase (PERK)/eukaryotic initiation factor 2alpha (eIF2α)/activating transcription factor 4 (ATF4) pathway and in apoptosis, all of which were significantly inhibited by pre-treatment with lenti-shPERK and an anti-RAGE antibody. The HMGB1-RAGE axis induces apoptotic injury during ARDS, possibly through PERK/eIF2α/ATF4-mediated ERs.

Bioinformatics analysis combined with experiments to verify potential autophagy genes in wound healing.

BackgroundThe skin is the most exposed tissue and has multiple functions. Wound healing is a major medical problem due to trauma and pathophysiological alterations suffered by patients. The aim of the present study was to search for potential autophagy genes associated with wound healing.MethodsThe GSE168760 dataset was obtained from the Gene Expression Omnibus (GEO) database, and sequencing results were obtained for 14 patient traumas at different time periods. Differentially expressed gene (DEG) analysis, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed. Immune cell and correlation analysis were performed for autophagy genes and DEGs. Peripheral blood was collected from patients at different time periods and Western blot (WB) assay was performed to verify autophagy genes.ResultsA total of 226 DEGs were screened on days 0, 7, and 14, of which 162 genes were upregulated and 64 genes were downregulated. Of these, eukaryotic translation initiation factor 2-alpha kinase 2 (EIF2AK2) and retinoblastoma 1 (RB1) were autophagy-associated genes. The DEGs were mainly involved in response to virus, cellular response to type I interferon Epstein-Barr virus infection, human papillomavirus infection, ribosome, hepatitis B and RIG-I-like. EIF2AK2 and RB1 showed positive correlation with some of the immune cells, and WB showed that EIF2AK2 and RB1 proteins were significantly increased with wound healing.ConclusionsThe comprehensive analysis of GEO data in the present study provides a new theoretical basis for the molecular pathogenesis of trauma healing and potential autophagy-related therapeutic targets.

Physical exercise positively modulates nonalcoholic steatohepatitis-related hepatic endoplasmic reticulum stress.

Obesity is a predictive factor for the development of nonalcoholic steatohepatitis (NASH). Although some of the mechanisms associated with NASH development are still elusive, its pathogenesis relies on a complex broad spectrum of (interconnected) metabolic-based disorders. We analyzed the effects of voluntary physical activity (VPA) and endurance training (ET), as preventive and therapeutic nonpharmacological strategies, respectively, against hepatic endoplasmic reticulum (ER) stress, ER-related proapoptotic signaling, and oxidative stress in an animal model of high-fat diet (HFD)-induced NASH. Adult male Sprague-Dawley rats were divided into standard control liquid diet (SCLD) or HFD groups, with sedentary, VPA, and ET subgroups in both (sedentary animals with access to SCLD[SS], voluntarily physically active animals with access to SCLD[SV], and endurance-trained animals with access to SCLD[ST] in the former and sedentary animals with access to liquid HFD[HS], voluntarily physically active animals with access to liquid HFD[HV], and endurance-trained animals with access to liquid HFD[HT] in the latter, respectively). Hepatic ER stress and ER-related proapoptotic signaling were evaluated by Western blot and reverse transcriptase-polymerase chain reaction; redox status was evaluated through quantification of lipid peroxidation, protein carbonyls groups, and glutathione levels as well as antioxidant enzymes activity. In SCLD-treated animals, VPA significantly decreased eukaryotic initiation factor-2 alpha (eIF2α). In HFD-treated animals, VPA significantly decreased eIF2α and phospho-inositol requiring enzyme-1 alpha(IRE1α) but ET significantly decreased eIF2α and significantly increased both spliced X-box binding protein 1 (sXBP1) and unspliced X-box binding protein 1; a significant increase of phosphorylated-eIF2α(p-eIF2α) to eIF2α ratio occurred in ET versus VPA. HS compared to SS disclosed a significant increase of total and reduced glutathione, HV compared to SV a significant increase of oxidized glutathione, HT compared to ST a significant increase of p-eIF2α to eIF2α ratio and sXBP1. Physical exercise counteracts NASH-related ER stress and its associated deleterious consequences through a positive and dynamical modulation of the hepatic IRE1α-X-box binding protein 1 pathway.

Stress Granules and Acute Ischemic Stroke: Beyond mRNA Translation.

Ischemic stroke is a leading cause of death and disability worldwide. Following an ischemic insult, cells undergo endoplasmic reticulum (ER) stress, which increases the ER’s protein-folding and degradative capacities and blocks the global synthesis of proteins by phosphorylating the eukaryotic translation initiation factor 2-alpha (eIF2α). Phosphorylation of eIF2α is directly related to the dynamics of stress granules (SGs), which are membraneless organelles composed of RNA-binding proteins and mRNA. SGs play a critical role in mRNA metabolism and translational control. Other translation factors are also linked to cellular pathways, including SG dynamics following a stroke. Because the formation of SGs is closely connected to mRNA translation, it is interesting to study the relationship between SG dynamics and cellular outcome in cases of ischemic damage. Therefore, in this review, we focus on the role of SG dynamics during cerebral ischemia.

Microcystin-LR induces ferroptosis in intestine of common carp (Cyprinus carpio)

Previous studies provide comprehensive evidence of the environmental hazards and intestinal toxicity of microcystin-LR (MC-LR) exposure. However, little is known about the mechanisms underlying the injury of intestine exposed to MC-LR. Juvenile common carp (Cyprinus carpio) were exposed to MC-LR (0 and 10 μg/L) for 15 days. The results suggest that organic anion-transporting polypeptides 3a1, 4a1, 2b1, and 1d1 mediate MC-LR entry into intestinal tissues. Lesion morphological features (vacuolization, deformation and dilation of the endoplasmic reticulum [ER], absence of mitochondrial cristae in mid-intestine), up-regulated mRNA expressions of ER stress (eukaryotic translation initiation factor 2-alpha kinase 3, endoplasmic reticulum to nucleus signaling 1, activating transcription factor [ATF] 6, ATF4, DNA damage-inducible transcript 3), iron accumulation, and down-regulated activity of glutathione peroxidase (GPx) and glutathione (GSH) content were all typical characteristics of ferroptosis in intestinal tissue following MC-LR exposure. GSH levels in intestinal tissue corroborated as the most influential GSH/GPx 4- related metabolic pathway in response to MC-LR exposure. Verrucomicrobiota, Planctomycetes, Bdellovibrionota, Firmicutes and Cyanobacteria were correlated with the ferroptosis-related GSH following MC-LR exposure. These findings provide new perspectives of the ferroptosis mechanism of MC-LR-induced intestinal injury in the common carp.

Pulmonary veno-occlusive disease in childhood-a rare disease not to be missed.

Pulmonary veno-occlusive disease (PVOD) is a rare disease leading to pulmonary hypertension and potentially death related to right heart failure and/or respiratory insufficiency. Clinical symptoms are heterogenous and nonspecific: fatigue, decreased exercise tolerance, shortness of breath on exertion, cough, dizziness, chest pain with exercise, palpitations, syncope, as well as nonspecific symptoms such as headache, poor appetite, pallor or perioral cyanosis. Mutations in the EIF2AK4 (eukaryotic translation initiation factor 2-alpha kinase 4) have been recently described, other risk factors include exposure to organic solvent and trichloroethylene, tobacco exposure and chemotherapy. Echocardiography helps to estimate right ventricular systemic pressure, but further diagnostic workup includes cardiac catheterization to confirm pulmonary hypertension and increased pulmonary vascular resistance. High-resolution computed tomography reveals typical findings: centrilobular ground-glass nodules or opacities, septal lines, thickened interlobular septa, mosaic perfusion, and lymphadenopathy. Histology remains the gold standard, but carries risks for the patient. Proper workup is essential in order to avoid incorrect diagnosis. Pulmonary hypertension targeted treatment has been used in patients with PVOD, however, experience is limited, vasodilatory effects on pulmonary vasculature may lead to deterioration of the patients and should be used with great caution. Lung transplantation is currently the only valid treatment option for patients with PVOD. With prolonged waiting time and progression of the disease mechanical support could be considered.

Modulation of Salubrinal-Mediated Endoplasmic Reticulum Stress in an Experimental Subarachnoid Hemorrhage Model

Perfusion abnormalities due to vasospasm remain a major cause of morbidity and mortality in subarachnoid hemorrhage (SAH). Despite a large number of clinical trials, therapeutic options with strong evidence for prevention and treatment of cerebral vasospasm are rare. In this study, we aimed to evaluate the neuroprotective effect of salubrinal (SLB) in endoplasmic reticulum stress-induced apoptosis, a catastrophic consequence of vasospasm. Thirty-two Wistar albino rats were divided into 4 groups of 8 rats each: control group, SAH, SAH+SLB, and SAH+nimodipine (NMN). In the SAH+SLB group, intraperitoneal SLB (1 mg/kg dose) administered 30 minutes after establishment of SAH, and in the SAH+NMN group, intraperitoneal NMN (0.1 mg/kg dose) was also administered 30 minutes after SAH. Higher total antioxidant status level, lower oxidative stress index, and significantly higher vascular endothelial growth factor-A (VEGF-A) level were detected in the SAH+SLB and SAH+NMN groups compared with the SAH group. There was a significant increase in eukaryotic translation initiation factor-2 alpha (elF2α) level in the SAH+SLB group compared with the SAH group. Histopathological evaluation revealed decrease in the subarachnoid hemorrhagic area, as well as in cortical edema and apoptotic bodies in the SAH+SLB and SAH+NMN groups. There was a significant decrease in caspase-3 staining in the SAH+SLB group, and the levels were significantly less in the SAH+NMN group than the SAH and SAH+SLB groups. SLB, selective inhibitor of eIF2α dephosphorylation, and NMN, a calcium channel blocker, can ameliorate SAH-induced damage. Inhibition of eIF2α dephosphorylation and enhanced VEGF-A production with SLB may protect brain tissue from apoptosis.

The PKR/P38/RIPK1 Signaling Pathway as a Therapeutic Target in Alzheimer's Disease.

Neuropathological lesions in Alzheimer’s disease (AD) include amyloid plaques formed by the accumulation of amyloid peptides, neurofibrillary tangles made of hyperphosphorylated tau protein, synaptic and neuronal degenerations, and neuroinflammation. The cause of AD is unknown, but according to the amyloid hypothesis, amyloid oligomers could lead to the activation of kinases such as eukaryotic translation initiation factor 2-alpha kinase 2 (PKR), p38, and receptor-interacting serine/threonine-protein kinase 1 (RIPK1), which all belong to the same stress-activated pathway. Many toxic kinase activations have been described in AD patients and in experimental models. A p38 mitogen-activated protein kinase inhibitor was recently tested in clinical trials but with unsuccessful results. The complex PKR/P38/RIPK1 (PKR/dual specificity mitogen-activated protein kinase kinase 6 (MKK6)/P38/MAP kinase-activated protein kinase 2 (MK2)/RIPK1) is highly activated in AD brains and in the brains of AD transgenic animals. To delineate the implication of this pathway in AD, we carried out a search on PubMed including PKR/MKK6/p38/MK2/RIPK1, Alzheimer, and therapeutics. The involvement of this signaling pathway in the genesis of AD lesions, including Aβ accumulations and tau phosphorylation as well as cognitive decline, is demonstrated by the reports described in this review. A future combination strategy with kinase inhibitors should be envisaged to modulate the consequences for neurons and other brain cells linked to the abnormal activation of this pathway.

Molecular mechanisms underlying the effects of the small molecule AMC-04 on apoptosis: Roles of the activating transcription factor 4-C/EBP homologous protein-death receptor 5 pathway

The unfolded protein response (UPR) is an emerging target pathway for cancer treatment owing to its ability to induce cell death. In our previous analysis of UPR-modulating small molecules, we had reported that piperazine oxalate derivative compounds (AMC-01–04) are able to promote increased phosphorylation of eukaryotic translation initiation factor-2 alpha (eIF2α). In this study, we found that AMC-04 induces apoptotic cell death via the activation of UPR in human breast and liver cancer cells. AMC-04 upregulated the expression of activating transcription factor-4 (ATF4)-C/EBP homologous protein (CHOP) and death receptor 5 (DR5) in cancer cells, as revealed by microarray analysis, small-interference RNA assay, and western blotting. From a mechanistic perspective, cytotoxic UPR pathway activation by AMC-04 is mediated by reactive oxygen species (ROS) and p38 mitogen-activated protein kinase (p38 MAPK) signaling. A chemical informatics approach predicted that AMC-04 modulates histone methyltransferase activity. Based on biochemical analysis, the activity of histone methyltransferases, including SUV39H1, SUV39H2, SETDB1, and EHMT1, was inhibited by AMC-04. Furthermore, chemical inhibition of the identified target proteins induced UPR activation and apoptotic cell death, suggesting that inhibition of histone methyltransferases is a promising strategy for cancer therapy. Taken together, we showed that the small molecule AMC-04 modulates epigenetic enzyme activity and mediates the link between cytotoxic UPR and histone modifications.