Phosphorylation Of Extracellular Regulated Kinase Research Articles

Involvement of ERK and Oxidative Stress in Airway Exposure to Cadmium Chloride Aggravates Airway Inflammation in Ovalbumin-Induced Asthmatic Mice.

Inhalation represents a significant route of cadmium (Cd) exposure, which is associated with an elevated risk of lung diseases. This research study aims to evaluate the impact of repeated low-dose cadmium inhalation on exacerbating airway inflammation induced by ovalbumin (OVA) in asthma-afflicted mice. Mice were grouped into four categories: control (Ctrl), OVA, cadmium chloride (CdCl2), and OVA + cadmium chloride (OVA + CdCl2). Mice in the OVA group displayed increased airway mucus secretion and peribronchial and airway inflammation characterized by eosinophil cell infiltration, along with elevated levels of Th2 cytokines (IL-4, IL-5, IL-13) in bronchoalveolar lavage fluids (BALFs). These parameters were further exacerbated in the OVA + CdCl2 group. Additionally, the OVA + CdCl2 group exhibited higher levels of the oxidative stress marker malondialdehyde (MDA), greater activity of glutathione peroxidase (GSH-Px), and higher phosphorylation of extracellular regulated kinase (ERK) in lung tissue. Treatment with U0126 (an ERK inhibitor) and α-tocopherol (an antioxidant) in the OVA + CdCl2 group resulted in reduced peribronchial and airway inflammation as well as decreased airway mucus secretion. These findings indicate that CdCl2 exacerbates airway inflammation in OVA-induced allergic asthma mice following airway exposure. ERK and oxidative stress are integral to this process, and the inhibition of these pathways significantly alleviates the adverse effects of CdCl2 on asthma exacerbation.

Isorhamnetin Downregulates MMP2 and MMP9 to Inhibit Development of Rheumatoid Arthritis through SRC/ERK/CREB Pathway.

To investigate the effect of isorhamnetin on the pathology of rheumatoid arthritis (RA). Tumor necrosis factor (TNF)- α -induced fibroblast-like synoviocytes (FLS) was exposed to additional isorhamnetin (10, 20 and 40 µ mol/L). Overexpression vectors for matrix metalloproteinase-2 (MMP2) or MMP9 or SRC were transfected to explore their roles in isorhamnetin-mediated RA-FLS function. RA-FLS viability, migration, and invasion were evaluated. Moreover, a collagen-induced arthritis (CIA) rat model was established. Rats were randomly divided to sham, CIA, low-, medium-, and high-dosage groups using a random number table (n=5 in each group) and administed with normal saline or additional isorhamnetin [2, 10, and 20 mg/(kg·day)] for 4 weeks, respectively. Arthritis index was calculated and synovial tissue inflammation was determined in CIA rats. The levels of MMP2, MMP9, TNF-α, interleukin-6 (IL-6), and IL-1 β, as well as the phosphorylation levels of SRC, extracellular regulated kinase (ERK), and cyclic adenosine monophosphate response element-binding (CREB), were detected in RA-FLS and synovial tissue. Molecular docking was also used to analyze the binding of isorhamnetin to SRC. In in vitro studies, isorhamnetin inhibited RA-FLS viability, migration and invasion (P<0.05). Isorhamnetin downregulated the levels of MMP2, MMP9, TNF-α, IL-6, and IL-1 β in RA-FLS (P<0.05). The overexpression of either MMP2 or MMP9 reversed isorhamnetin-inhibited RA-FLS migration and invasion, as well as the levels of TNF-α, IL-6, and IL-1 β (P<0.05). Furthermore, isorhamnetin bound to SRC and reduced the phosphorylation of SRC, ERK, and CREB (P<0.05). SRC overexpression reversed the inhibitory effect of isorhamnetin on RA-FLS viability, migration and invasion, as well as the negative regulation of MMP2 and MMP9 (P<0.05). In in vivo studies, isorhamnetin decreased arthritis index scores (P<0.05) and alleviated synovial inflammation. Isorhamnetin reduced the levels of MMP2, MMP9, TNF-α, IL-6, and IL-1 β, as well as the phosphorylation of SRC, ERK, and CREB in synovial tissue (P<0.05). Notably, the inhibitory effect of isorhamnetin was more pronounced at higher concentrations (P<0.05). Isorhamnetin exhibited anti-RA effects through modulating SRC/ERK/CREB and MMP2/MMP9 signaling pathways, suggesting that isorhamnetin may be a potential therapeutic agent for RA.

Sertraline Pre-Treatment Attenuates Hemorrhagic Transformation Induced in Rats after Cerebral Ischemia Reperfusion via Down Regulation of Neuronal CD163: Involvement of M1/M2 Polarization Interchange and Inhibiting Autophagy

Cerebral ischemia reperfusion (I/R) is one of the neurovascular diseases which leads to severe brain deterioration. Haemorrhagic transformation (HT) is the main complication of ischemic stroke. It exacerbates by reperfusion, causing a more deleterious effect on the brain and death. The current study explored the protective effect of sertraline (Sert) against cerebral I/R in rats by inhibiting HT, together with the molecular pathways involved in this effect. Forty-eight wister male rats were divided into 4 groups: Sham, Sert + Sham, I/R, and Sert + I/R. The ischemic model was induced by bilateral occlusion of the common carotid artery for 20 min, then reperfusion for 24 h. Sertraline (20 mg/kg, p.o.) was administrated for 14 days before exposure to ischemia. Pre-treatment with Sert led to a significant attenuation of oxidative stress and inflammation. In addition, Sert attenuated phosphorylation of extracellular regulated kinases and nuclear factor kappa—p65 expression, consequently modulating microglial polarisation to M2 phenotype. Moreover, Sert prevented the hemorrhagic transformation of ischemic stroke as indicated by the notable decrease in neuronal expression of CD163, activity of Heme oxygenase-2 and matrix metalloproteinase-2 and 9 levels. In the same context, Sert decreased levels of autophagy and apoptotic markers. Furthermore, histological examination, Toluidine blue, and Prussian blue stain aligned with the results. In conclusion, Sert protected against cerebral I/R damage by attenuating oxidative stress, inflammation, autophagy, and apoptotic process. It is worth mentioning that our study was the first to show that Sert inhibited hemorrhagic transformation.Graphical The protective effect of sertraline against injury induced by cerebral ischemia reperfusion via inhibiting Hemorrhagic transformation.

Phenyl-2-aminoethyl selenide ameliorates hippocampal long-term potentiation and cognitive deficits following doxorubicin treatment.

Chemotherapy-induced memory loss ("chemobrain") can occur following treatment with the widely used chemotherapeutic agent doxorubicin (DOX). However, the mechanisms through which DOX induces cognitive dysfunction are not clear, and there are no commercially available therapies for its treatment or prevention. Therefore, the aim of this study was to determine the therapeutic potential of phenyl-2-aminoethyl selenide (PAESe), an antioxidant drug previously demonstrated to reduce cardiotoxicity associated with DOX treatment, against DOX-induced chemobrain. Four groups of male athymic NCr nude (nu/nu) mice received five weekly tail-vein injections of saline (Control group), 5 mg/kg of DOX (DOX group), 10 mg/kg PAESe (PAESe group), or 5 mg/kg DOX and 10 mg/kg PAESe (DOX+PAESe group). Spatial memory was evaluated using Y-maze and novel object location tasks, while synaptic plasticity was assessed through the measurement of field excitatory postsynaptic potentials from the Schaffer collateral circuit. Western blot analyses were performed to assess hippocampal protein and phosphorylation levels. In this model, DOX impaired synaptic plasticity and memory, and increased phosphorylation of protein kinase B (Akt) and extracellular-regulated kinase (ERK). Co-administration of PAESe reduced Akt and ERK phosphorylation and ameliorated the synaptic and memory deficits associated with DOX treatment.

Carnosic acid inhibits reactive oxygen species-dependent neutrophil extracellular trap formation and ameliorates acute respiratory distress syndrome

AimsInfiltration of activated neutrophils into the lungs is a hallmark of acute respiratory distress syndrome (ARDS). Neutrophilic inflammation, particularly neutrophil extracellular traps (NETs), is proposed as a useful target for treating ARDS. Carnosic acid (CA) is a food additive; however, its anti-neutrophilic activity in the treatment of ARDS has not been well established. The hypothesis of present study is to confirm that CA alleviates ARDS by suppressing neutrophilic inflammation and oxidative damage. Main methodsGeneration of superoxide anions and reactive oxygen species (ROS), induction of elastase degranulation, and formation of NETs by human neutrophils were assayed using spectrophotometry, flow cytometry, and immunofluorescent microscopy. Immunoblotting was performed to determine the cellular mechanisms involved. Cell-free radical systems were used to test antioxidant activities. The therapeutic effect of CA was evaluated in a lipopolysaccharide (LPS)-induced ARDS mouse model. Key findingsCA greatly reduced superoxide anion production, ROS production, elastase release, cluster of differentiation 11b expression, and cell adhesion in activated human neutrophils. Mechanistic studies have demonstrated that CA suppresses phosphorylation of extracellular regulated kinase and c-Jun N-terminal kinase in activated neutrophils. CA effectively scavenges reactive oxygen and nitrogen species, but not superoxide anions. This is consistent with the finding that CA is effective against ROS-dependent NET formation. CA treatment significantly improved pulmonary neutrophil infiltration, oxidative damage, NET formation, and alveolar damage in LPS-induced mice. SignificanceOur data suggested the potential application of CA for neutrophil-associated ARDS therapy.

AIMP1 promotes multiple myeloma malignancy through interacting with ANP32A to mediate histone H3 acetylation

Multiple myeloma (MM) is the second most common hematological malignancy. An overwhelming majority of patients with MM progress to serious osteolytic bone disease. Aminoacyl-tRNA synthetase-interacting multifunctional protein 1 (AIMP1) participates in several steps during cancer development and osteoclast differentiation. This study aimed to explore its role in MM. The gene expression profiling cohorts of MM were applied to determine the expression of AIMP1 and its association with MM patient prognosis. Enzyme-linked immunosorbent assay, immunohistochemistry, and Western blotting were used to detect AIMP1 expression. Protein chip analysis, RNA-sequencing, and chromatin immunoprecipitation and next-generation sequencing were employed to screen the interacting proteins and key downstream targets of AIMP1. The impact of AIMP1 on cellular proliferation was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro and a xenograft model in vivo. Bone lesions were evaluated using tartrate-resistant acid phosphatase staining in vitro. A NOD/SCID-TIBIA mouse model was used to evaluate the effect of siAIMP1-loaded exosomes on bone lesion formation in vivo. AIMP1 expression was increased in MM patients and strongly associated with unfavorable outcomes. Increased AIMP1 expression promoted MM cell proliferation in vitro and in vivo via activation of the mitogen-activated protein kinase (MAPK) signaling pathway. Protein chip assays and subsequent experiments revealed that AIMP1 interacted with acidic leucine-rich nuclear phosphoprotein 32 family member A (ANP32A) to regulate histone H3 acetylation. In addition, AIMP1 increased histone H3 acetylation enrichment function of GRB2-associated and regulator of MAPK protein 2 (GAREM2) to increase the phosphorylation of extracellular-regulated kinase 1/2 (p-ERK1/2). Furthermore, AIMP1 promoted osteoclast differentiation by activating nuclear factor of activated T cells c1 (NFATc1) in vitro. In contrast, exosome-coated small interfering RNA of AIMP1 effectively suppressed MM progression and osteoclast differentiation in vitro and in vivo. Our data demonstrate that AIMP1 is a novel regulator of histone H3 acetylation interacting with ANP32A in MM, which accelerates MM malignancy via activation of the MAPK signaling pathway.

Curcumin Induces Apoptosis of Chemoresistant Lung Cancer Cells via ROS-Regulated p38 MAPK Phosphorylation.

This study aimed to challenge chemoresistance by curcumin (CUR) with drug-selected human lung cancer A549 sublines that continuously proliferate in the present of docetaxel (DOC) and vincristine (VCR). Their sensitivities to CUR were measured by MTT assay and the particular intracellular reactive oxygen species (ROS) was detected by fluorescence activated cell sorting (FACS) analysis. Apoptosis was analyzed by Annexin V assay of the flow cytometry. Inhibitors and RNA interference were used to examine the signaling pathway regulated by the kinases. The obtained data demonstrated that CUR induces chemoresistant cell apoptosis by generating ROS and application of N-acetylcysteine (NAC) blocks ROS production, resulting in apoptosis suppression. Phosphorylation of extracellular regulated kinase (ERK), p38 MAPK, and eIF-2α were increased but c-Jun N-terminal kinase (JNK) did not increase when chemoresistant cells were treated with CUR. Downregulation of ERK and p38 MAPK phosphorylation by their inhibitors had no effect on CUR-induced apoptosis. Interestingly, the knockdown of p38 MAPK with shRNA significantly reduced CUR-induced apoptosis on the chemoresistant sublines. Phosphorylation of the eIF-2α protein was inhibited when p38 MAPK was knocked down in DOC-resistant A549 cells, but a high level of phosphorylated eIF-2α protein remained on the VCR-resistant A549 cells when p38 MAPK was knocked down. These data confirmed that CUR-augmented ROS potently induced apoptosis via upregulated p38 MAPK phosphorylation. Therefore, activated p38 MAPK is considered a pro-apoptotic signal for CUR-induced apoptosis of chemoresistant human lung cancer cells.

Human Milk Oligosaccharide L‐N‐Tetraose Activates GPR35 on Vagal Afferent Neurons In Vitroand Reduces High Fat Diet‐Induced Obesity in Male Mice

Obesity is associated with altered gut microbiota; dietary supplementation with prebiotics improves metabolic outcomes in obesity, an effect ascribed to improved microbial dysbiosis. However, alternative mechanisms have not been fully explored. We have shown that prebiotic milk oligosaccharides (MOs) decrease weight gain and food intake in mice fed a high‐fat diet (HFD), and improve cholecystokinin (CCK)‐induced satiety signaling. It has recently been shown that the human MO lacto‐N‐tetraose (LNT) is a ligand for the G‐protein coupled receptor, GPR35. GPR35 is highly expressed by vagal afferent neurons (VAN) where it is co‐expressed with the CCKAR. HFD reduces endogenous GPR35 ligands and sensitivity to CCK, but the role of GPR35 and its ligands eg LNT, in satiety signaling via the vagal afferent pathway have not been investigated. Here we test the hypothesis that LNT reduces HFD‐induced weight gain and hyperphagia in mice via a direct effect on GPR35 expressed by VAN.MethodsMice were maintained on low‐fat diet (10% kcal fat), HFD (45% fat kcal), or HFD supplemented with 10% LNT for 8 weeks (male, n=5‐9/group). To determine if VAN are directly activated by GPR35 ligands, VAN from adult male Wistar rats were cultured and treated with the GPR35 agonist zaprinast (100 µM), LNT (10 mM), or D‐lactose (constituent of LNT; 10 mM) for 15 minutes after 1 hour pre‐incubation with the GPR35 competitive antagonist CID‐2745687 (100 µM) or vehicle (n=4/treatment). Phosphorylation of extracellular regulated kinase (ERK) relative to total ERK (pERK/ERK) was determined by western blot and used as an indicator of VAN activation.ResultsLNT administration significantly reduced body weight, fat mass, and improved HFD‐induced hyperphagia (p&lt;0.05). Treatment of VAN with the GPR35 agonist zaprinast increased pERK/ERK (p&lt;0.05) relative to vehicle; zaprinast‐induced activation was prevented by the CID‐2745687. LNT, but not D‐lactose, also activated VAN, an effect inhibited by the GPR35 antagonist.ConclusionsLNT may decrease food intake via a direct effect on VAN, possibly by increasing sensitivity to peripheral satiety signals. This work reveals a potential peripheral therapeutic target for ameliorating diet‐induced weight gain.

Chlorogenic Acid as a Positive Regulator in LPS-PG-Induced Inflammation via TLR4/MyD88-Mediated NF-κB and PI3K/MAPK Signaling Cascades in Human Gingival Fibroblasts.

Gingival inflammation is one of the main causes that can be related to various periodontal diseases. Human gingival fibroblast (HGF) is the major constituent in periodontal connective tissue and secretes various inflammatory mediators, such as nitric oxide (NO) and prostaglandin E2 (PGE2), upon lipopolysaccharide stimulation. This study is aimed at investigating the anti-inflammatory mechanism of chlorogenic acid (CGA) on Porphyromonas gingivalis LPS- (LPS-PG-) stimulated HGF-1 cells. The concentration of NO and PGE2, as well as their responsible enzymes, inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2), was analyzed by Griess reaction, ELISA, and western blot analysis. LPS-PG sharply elevated the production and protein expression of inflammatory mediators, which were significantly attenuated by CGA treatment in a dose-dependent manner. CGA treatment also suppressed activation of Toll-like receptor 4 (TLR4)/myeloid differentiation primary response gene 88 (MyD88) and nuclear factor- (NF-) κB in LPS-PG-stimulated HGF-1 cells. Furthermore, LPS-PG-induced phosphorylation of extracellular regulated kinase (ERK) and Akt was abolished by CGA treatment, while c-Jun N-terminal kinase (JNK) and p38 did not have any effect. Consequently, these results suggest that CGA ameliorates LPS-PG-induced inflammatory responses by attenuating TLR4/MyD88-mediated NF-κB, phosphoinositide-3-kinase (PI3K)/Akt, and MAPK signaling pathways in HGF-1 cells.

Exosomes from H5N1 avian influenza virus-infected chickens regulate antiviral immune responses of chicken immune cells

Exosomes (membrane-derived vesicles) enable intracellular communication by delivering lipids, proteins, DNA, and RNA from one cell to another. Highly pathogenic avian influenza virus (HPAIV) H5N1 causes considerable economic loss in the poultry industry and poses a public health concern. The host innate immune system defends against H5N1 infection by activating antiviral immune responses. This study aimed to demonstrated that immunomodulatory effects of exosomes from HPAIV H5N1-infected White Leghorn chickens on chicken macrophages, fibroblasts, T cell, and B cell lines. The expression of type I interferons (IFN-α and -β) were highly upregulated in immune-related cell lines after treatment with exosomes derived from H5N1-infected chickens. Levels of pro-inflammatory cytokines, such as IFN-γ, IL-1β, and CXCL8, were also elevated by the exosomes. The mitogen-activated protein kinase (MAPK) signaling pathway was stimulated in immune-related cells by such exosomes via phosphorylation of extracellular regulated kinases 1/2 and p38 signaling molecules. Furthermore, the H5N1 viral proteins, nucleoprotein (NP) and non-structural protein (NS1), were packaged in exosomes and successfully transferred to non-infected immune-related cells. Therefore, exosomes from H5N1-infected chickens induced pro-inflammatory cytokine expression and stimulated the MAPK signaling pathway by delivering key viral proteins. These findings would aid better understanding of the mechanism underlying the modulation of antiviral immune responses of host immune-related cells by viral-protein-carrying exosomes and support their further application as a novel exosome-based H5N1 AIV vaccine platform.

Shoc2 recognizes bacterial flagellin and mediates antibacterial Erk/Stat signaling in an invertebrate.

Flagellin is a key bacterial virulence factor that can stimulate molecular immune signaling in both animals and plants. The detailed mechanisms of recognizing flagellin and mounting an efficient immune response have been uncovered in vertebrates; however, whether invertebrates can discriminate flagellin remains largely unknown. In the present study, the homolog of human SHOC2 leucine rich repeat scaffold protein in kuruma shrimp (Marsupenaeus japonicus), designated MjShoc2, was found to interact with Vibrio anguillarum flagellin A (FlaA) using yeast two-hybrid and pull-down assays. MjShoc2 plays a role in antibacterial response by mediating the FlaA-induced expression of certain antibacterial effectors, including lectin and antimicrobial peptide. FlaA challenge, via MjShoc2, led to phosphorylation of extracellular regulated kinase (Erk), and the subsequent activation of signal transducer and activator of transcription (Stat), ultimately inducing the expression of effectors. Therefore, by establishing the FlaA/MjShoc2/Erk/Stat signaling axis, this study revealed a new antibacterial strategy in shrimp, and provides insights into the flagellin sensing mechanism in invertebrates.

Downregulation of Signal Regulatory Protein Alfa 1 in K562 Cells Results in the Aberrant Cell Growth in Low Serum Culture

Signal regulatory protein (SIRP)-α1 is a myeloid inhibitory immunoreceptor. SIRPα1 expression is significantly reduced in the majority of myeloid malignancies. SIRPα1 is a negative regulator of signaling and the reduced expression is considered to play a role in the pathogenesis of these diseases through aberrant signaling, but the biological roles of SIRPα1 remain largely unknown. In this study, by using SIRP-α1-knockdown chronic myeloid leukemia K562 (K562SIRP-α1KD) cells, I found that in low (0.1, 0.3%) serum media, the cell growth was increased until day 5, whereas control cells did not proliferate beyond day 2 under the same serum conditions. Consistently, in K562SIRP-α1KD cells, 2 days of culture in 0.3% serum increased the proportion of S-phase cells, as well as bromodeoxyuridine (BrdU) incorporation compared to their controls. Moreover, serum stimulation experiment revealed that Brd-U positive cells were significantly increased in K562SIRPα1 KD cells. Furthermore, in K562SIRP-α1KD cells, phosphorylation of extracellular regulated kinase (ERK) and Akt was potently increased under low serum conditions. Collectively, these data suggested that down-regulation of SIRPα1 led to the constitutive activation of these aberrant signaling, as well as abnormal growth, in K562 cells.

Saikosaponin A and D Inhibit Adipogenesis via the AMPK and MAPK Signaling Pathways in 3T3-L1 Adipocytes

Obesity is a lipid metabolism disorder caused by genetic, medicinal, nutritional, and other environmental factors. It is characterized by a complex condition of excess lipid accumulation in adipocytes. Adipogenesis is a differentiation process that converts preadipocytes into mature adipocytes and contributes to excessive fat deposition. Saikosaponin A (SSA) and saikosaponin D (SSD) are triterpenoid saponins separated from the root of the Bupleurum chinensis, which has long been used to treat inflammation, fever, and liver diseases. However, the effects of these constituents on lipid accumulation and obesity are poorly understood. We investigated the anti-obesity effects of SSA and SSD in mouse 3T3-L1 adipocytes. The MTT assay was performed to measure cell viability, and Oil Red O staining was conducted to determine lipid accumulation. Various adipogenic transcription factors were evaluated at the protein and mRNA levels by Western blot assay and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Here, we showed that SSA and SSD significantly inhibited lipid accumulation without affecting cell viability within the range of the tested concentrations (0.938–15 µM). SSA and SSD also dose-dependently suppressed the expression of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding protein alpha (C/EBPα), sterol regulatory element binding protein-1c (SREBP-1c), and adiponectin. Furthermore, the decrease of these transcriptional factors resulted in the repressed expression of several lipogenic genes including fatty acid binding protein (FABP4), fatty acid synthase (FAS), and lipoprotein lipase (LPL). In addition, SSA and SSD enhanced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and its substrate, acetyl-CoA carboxylase (ACC), and inhibited the phosphorylation of extracellular-regulated kinase 1/2 (ERK1/2) and p38, but not c-Jun-N-terminal kinase (JNK). These results suggest that SSA and SSD inhibit adipogenesis through the AMPK or mitogen-activated protein kinase (MAPK) pathways in the early stages of adipocyte differentiation. This is the first study on the anti-adipogenic effects of SSA and SSD, and further research in animals and humans is necessary to confirm the potential of saikosaponins as therapeutic agents for obesity.

Obesity increases neuropathic pain via the AMPK-ERK-NOX4 pathway in rats.

This study focused on the relationship between extracellular-regulated kinase (ERK) and obesity-induced increases in neuropathic pain. We fed rats a high-fat diet to establish the obesity model, and rats were given surgery to establish the chronic compression of the dorsal root ganglia (CCD) model. U0126 was applied to inhibit ERK, and metformin or 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) was applied to cause AMP-activated protein kinase (AMPK) activation. Paw withdrawal mechanical threshold (PWMT) were calculated to indicate the level of neuropathic pain. The data indicated that compared with normal CCD rats, the PWMT of obese CCD rats were decreased, accompanied with an increase of ERK phosphorylation, NAD(P)H oxidase 4 (NOX4) protein expression, oxidative stress and inflammatory level in the L4 to L5 spinal cord and dorsal root ganglia (DRG). Administration of U0126 could partially elevate the PWMT and reduce the protein expression of NOX4 and the above pathological changes in obese CCD rats. In vitro, ERK phosphorylation, NOX4 protein expression increased significantly in DRG neurons under the stimulation of palmitic acid (PA), accompanied with increased secretion of inflammatory factors, oxidative stress and apoptosis level, while U0126 partially attenuated the PA-induced upregulation of NOX4 and other pathological changes. In the rescue experiment, overexpression of NOX4 abolished the above protective effect of U0126 on DRG neurons in high-fat environment. Next, we explore upstream mechanisms. Metformin gavage significantly reduced neuropathic pain in obese CCD rats. For the mechanisms, activating AMPK with metformin (obese CCD rats) or AICAR (DRG neurons in a high-fat environment) not only inhibited the ERK-NOX4 pathway, but also improved oxidative stress and inflammation caused by high-fat. In conclusion, the AMPK-ERK-NOX4 pathway may has a pivotal role in mediating obesity-induced increases in neuropathic pain.

Bioactivity-Guided Extract Optimization of Osmanthus fragrans var. aurantiacus Leaves and Anti-Inflammatory Activities of Phillyrin.

The aim of this study was to identify the optimal extraction conditions for leaves of Osmanthus fragrans var. aurantiacus. Inhibitory effects of various extracts on NO production were compared. Antioxidant evaluations for total phenol and flavonoid contents were carried out using various extracts of O. fragrans var. aurantiacus leaves obtained under optimal extraction conditions that showed the greatest effect on NO production. The optimal method for extracting O. fragrans var. aurantiacus leaves resulted in an extract named OP OFLE. OP OFLE showed DPPH and ABTS radical scavenging activities in a concentration-dependent manner. Phillyrin (PH) was isolated as a major compound from OP OFLE by HPLC/DAD analysis. OP OFLE and PH reduced inducible nitric oxide (iNOS) and cyclooxygenase (COX)-2 protein expression and downregulated proinflammatory cytokines such as interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor (TNF)-α in LPS-stimulated RAW 264.7 and HT-29 cells. To determine the signal pathway involved in the inhibition of NO production, a Western blot analysis was performed. Results showed that OP OFLE decreased phosphorylation of extracellular regulated kinase (pERK) 1/2 and the expression of nuclear factor-kappa B (NF-κB). Our results suggest that extracts of O. fragrans var. aurantiacus leaves and its major components have biological activities such as antioxidative and anti-inflammatory properties.

Cetyltrimethylammonium Bromide Attenuates the Mesenchymal Characteristics of Hypopharyngeal Squamous Cell Carcinoma Through Inhibiting the EGFR/PI3K/AKT Signaling Pathway.

Cetyltrimethylammonium bromide (CTAB), a quaternary ammonium surfactant, was shown to have antitumor effects in a cellular mode of head and neck squamous cell carcinoma (HNSCC), modulating apoptotic and cytotoxic processes. However, the mechanisms by which CTAB exerts its effects against the epithelial- mesenchymal transition in HNSCC remain poorly understood. In the present study, we investigated whether CTAB inhibits cellular mobility and invasiveness of hypopharyngeal squamous cell carcinoma (HPSCC) cells. WST-1, cell-cycle phase distribution, and wound healing, as well as transwell assays were conducted. Changes in protein expression patterns and related signaling pathways involved in effects of CTAB on HPSCC cell lines were evaluated by western blotting. Treatment of human HPSCC cell lines with CTAB significantly altered their morphology from spindle-like to cobblestone-like by diminishing mesenchymal-like phenotypic characteristics. CTAB also hindered cell functional properties, including migration and invasion, independently of cell viability. In addition, western blot results demonstrated that treatment with CTAB reduced expression of mesenchymal markers. Further investigation showed that CTAB treatment suppressed the phosphorylation of extracellular-regulated kinase 1/2, mechanistic target of rapamycin kinase and AKT serine/threonine kinase 1. CTAB also repressed the expression and phosphorylation levels of epidermal growth factor receptor (EGFR) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), and the partial restoration of mesenchymal phenotype by EGF addition confirmed that CTAB inhibited migration and invasion in HPSCC cells by blocking the EGFR signaling pathway. Our results suggest that CTAB is involved in the suppression of EGFR-mediated mesenchymal phenotype and the molecular mechanism by which CTAB obstructs HPSCC cell metastasis may represent a promising strategy for use in HPSCC treatment.

Sustained O‐GlcNAcylation causes ERK Signal and APP Amplification

Activation of ERK (Extra-cellular Regulated Kinase) signal plays a major role in metabolic diseases such as cancer and Alzheimer's. Ingenuity Pathway Analysis (IPA) of RNA-Seq data from long-term O-GlcNAcase (OGA) enzyme inhibitor- Thiamet-G (TMG) treated SH-SY5Y (neuroblastoma) cells, which elevates O-GlcNAc levels, indicated ERK Signaling as a top upregulated pathway. O-GlcNAcylation consists of the addition of a single N-acetyl-glucosamine residue (GlcNAc) to specific serine/threonine residues of proteins by the enzyme OGT (O-GlcNAc Transferase) and the removal of O-GlcNAc is catalyzed by the enzyme OGA. O-GlcNAc is highly abundant and is known to modulate kinase activity. Thus, to further investigate the mechanism by which O-GlcNAcylation activates ERK, we did a serum reactivation time-course and found that there is an amplification in ERK phosphorylation after long-term TMG treatment in HeLa and SH-SY5Y cells. Next, TGF-β stimulation that specifically activates ERK signaling also indicated an increase in ERK phosphorylation with long-term TMG treatment, confirming a robust ERK activation with TMG treatment. ERK phosphorylation oscillates with time after mitogen activation; therefore, we wanted to see if TMG treatment influenced ERK oscillation for a period of 24 hours. Serum reactivation revealed an oscillation in phosphorylated-ERK expression within a 24-hour period, where it reaches a maximum at 4 hours and slowly decreases at 8,12 and 24 hours upon long-term TMG treatment. Next, we wanted to further evaluate the mechanism by which TMG treatment increases ERK phosphorylation. Of note, we did not measure any O-GlcNAcylation on ERK; hence, we probed the expression of activated mitogen activated protein kinase-kinase (phosphorylated MEK) which phosphorylates ERK and Dual specificity phosphatases (DUSPs), which dephosphorylate ERK. Interestingly, serum reactivation time course showed an increase in both phosphorylated-MEK and total DUSP4 with TMG treatment. In addition to the use of pharmacological OGA inhibitor, we measured the effect of OGT knock-down (KD) and OGA KD on ERK signaling in SH-SY5Y and HeLa cells. There was amplification in ERK phosphorylation even after OGT knock-down (OGT KD) which lowers the level of O-GlcNAcylation, in contrast to long-term TMG treatment which increases O-GlcNAcylation. These data suggest that the cycling of the modification on and off substrates is key to ERK pathway regulation. Recent research also shows APOE4 stimulates the transcription of amyloid precursor protein (APP) via a non-canonical ERK signaling pathway, leading to increased amyloid-beta secretion in Alzheimer's disease pathogenesis. Therefore, we wanted to see if there is an increase in the expression of APP in the long-term TMG treated SH-SY5Y cells after serum reactivation, and we saw an increase in APP expression correlating with amplification of ERK signaling. Further evaluation of these molecular mechanisms to elucidate how O-GlcNAcylation amplifies ERK signaling and understand if O-GlcNAcylation and ERK activation work together to increase the transcription of APP are necessary.

Sodium houttuyfonate relieves acute lung injury by nano micellar carrier and inhibits mitogen-activated protein kinase and nuclear factor kappa-B activation in mice

Acute lung injury (ALI) is characterized by increased pulmonary vascular permeability in response to the accumulation of inflammatory cells, release of inflammatory cytokines, and activated oxidative stress. The present study was performed to investigate the effect of sodium houttuyfonate (SH), an extract of Houttuynia cordata, on inflammatory response and oxidative stress in ALI induced by lipopolysaccharides (LPS). Male C57BL/6 mice were randomly allocated to control, LPS, dimethyl sulfoxide (DMSO), and SH groups. The ALI model was established by intratracheal LPS injection. Lung tissue was collected 6 h after LPS injection for histopathological analysis, measurement of wet-to-dry ratio, myeloperoxidase (MPO) and oxidative stress levels, and the p38, jun N-terminal kinase (JNK), extracellular regulated kinase (ERK), and p65 phosphorylation levels. Bronchoalveolar fluid (BALF) was collected for the detection of protein concentration, MPO and cytokine levels. The histopathological test showed that SH significantly alleviates damage to pulmonary tissue. Improved vascular permeability was indicated by reduced BALF protein level and lung wet-to-dry ratio in the SH group. MPO levels were decreased in lung tissue and BALF. Oxidative stress and inflammatory responses were inhibited by SH, as indicated by MDA, SOD and cytokine levels. The MAPK and NF-KB pathways were inhibited as shown by the attenuated phosphorylation of p38, JNK, ERK and p65. Sodium houttuyfonate exhibited a protective role against LPS-induced lung injury through anti-oxidative and anti-inflammatory effects. The MAPK and NF-K B pathways may be inhibited by sodium houttuyfonate. Sodium Houttuynin has a good effect on a variety of acute infectious diseases, but its solubility and stability are insufficient, which limits its efficacy. Nano delivery system can enhance the effective ingredients of traditional Chinese medicine, reduce the toxic and side effects of drugs, and improve their medicinal properties. Therefore, this paper adopts nano delivery system to assist drug use and improve research efficiency.

IARS2 regulates proliferation, migration, and angiogenesis of human umbilical vein endothelial cells.

In this study, we aimed at investigating the role of isoleucyl-tRNA synthetase in the growth, migration, and angiogenesis of human umbilical vein endothelial cells and the underlying molecular mechanism. To assess the role of isoleucyl-tRNA synthetase, we silenced isoleucyl-tRNA synthetase in human umbilical vein endothelial cells using lentiviral 2 specific short hairpin RNAs (short hairpin RNAs 1 and 2) and examined silencing efficiency using real time quantitative polymerase chain reaction and western blot analyses. Short hairpin RNAs 1-isoleucyl-tRNA synthetase had greater knockdown efficiency, it was used in the entire downstream analysis. Short hairpin RNAs 1- isoleucyl-tRNA synthetase silencing effects on cell proliferation, cell colony generation, cell migration, as well as angiogenesis were assessed using cell counting kit-8, colony development, cell migration, and angiogenesis tube formation assays, respectively. Compared to the control group, anti-isoleucyl-tRNA synthetase short hairpin RNAs significantly silenced isoleucyl-tRNA synthetase expression in human umbilical vein endothelial cells, and suppressed their proliferation, migration, and angiogenic capacity. To characterize the underlying mechanism, western blot analyses showed that isoleucyl-tRNA synthetase knockdown suppressed phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3β, and β-catenin. We have shown, for the first time, the critical role of isoleucyl-tRNA synthetase in human umbilical vein endothelial cells. Our data show that isoleucyl-tRNA synthetase knockdown suppresses human umbilical vein endothelial cell proliferation, migration, and angiogenesis. We have also shown that isoleucyl-tRNA synthetase knockdown suppresses phosphorylation of extracellular-regulated kinase ½ and protein-serine- threonine kinase, as well as expression of vascular endothelial growth factor, GSK-3β, and β-catenin. Together, these data highlight isoleucyl-tRNA synthetase as a potential antitumor anti-angiogenic target.

Signaling through the type 2 cannabinoid receptor regulates the severity of acute and chronic graft-versus-host disease

Graft-versus-host disease (GVHD) pathophysiology is a complex interplay between cells that comprise the adaptive and innate arms of the immune system. Effective prophylactic strategies are therefore contingent upon approaches that address contributions from both immune cell compartments. In the current study, we examined the role of the type 2 cannabinoid receptor (CB2R), which is expressed on nearly all immune cells, and demonstrated that absence of the CB2R on donor CD4+ or CD8+ T cells or administration of a selective CB2R pharmacological antagonist exacerbated acute GVHD lethality. This was accompanied primarily by the expansion of proinflammatory CD8+ T cells, indicating that constitutive CB2R expression on T cells preferentially regulated CD8+ T-cell alloreactivity. Using a novel CB2ReGFP reporter mouse, we observed significant loss of CB2R expression on T cells, but not macrophages, during acute GVHD, indicative of differential alterations in receptor expression under inflammatory conditions. Therapeutic targeting of the CB2R with the agonists Δ9-tetrahydrocannabinol (THC) and JWH-133 revealed that only THC mitigated lethal T cell–mediated acute GVHD. Conversely, only JWH-133 was effective in a sclerodermatous chronic GVHD model where macrophages contributed to disease biology. In vitro, both THC and JWH-133 induced arrestin recruitment and extracellular regulated kinase phosphorylation via CB2R, but THC had no effect on CB2R-mediated inhibition of adenylyl cyclase. This study shows that the CB2R plays a critical role in the regulation of GVHD and suggests that effective therapeutic targeting is dependent upon agonist signaling characteristics and receptor selectivity in conjunction with the composition of pathogenic immune effector cells.