Static electric field (SEF) exposure promotes the proliferation of B lymphocytes

With the rapid development of ultra-high voltage direct current (UHV DC) transmission technology, the intensity of electric fields in the surrounding environment of UHV DC transmission lines significantly increased, which raised public concerns about the potential health effects of electric fields. Previous studies have shown that the exposure of electromagnetic field was associated with cancer. B lymphocytes can produce autoantibodies and tumor growth factors through proliferation, which contributes to the development of cancer. Therefore, this study explored the effect and mechanism of static electric field (SEF) generated by DC transmission lines on the proliferation levels of B lymphocytes. Male mice were exposed to SEF. After the exposure of 7 and 14 days, the proliferation levels of B lymphocytes in the spleens of mice were measured, respectively. To validate biological effect discovered in animal experiments and elucidate the mechanism of the effect from the perspective of signaling pathways, lymphocytes were exposed to SEF. After the exposure of 24, 48 or 72 h, the proliferation levels of B lymphocytes, the expression levels of key proteins and cell cycle were determined. This study found that SEF exposure activated NF-κB pathway by stimulating ERK1/2 pathway and promoted B lymphocytes to enter S phase from G0/G1 phase. Meanwhile, SEF exposure also promoted B lymphocytes to enter G2 phase. Namely, SEF exposure significantly promoted the proliferation of B lymphocytes. This discovery provided theoretical and practical support for the prevention or application of negative or positive effects caused by SEF exposure and provided directions for future research.

Prepubertal exposure to copper oxide nanoparticles induces Leydig cell injury with steroidogenesis disorders in mouse testes

Copper oxide nanoparticles (CuONPs) are metallic multifunctional nanoparticles with good conductive, catalytic and antibacterial characteristics that have shown to cause reproductive dysfunction. However, the toxic effect and potential mechanisms of prepubertal exposure to CuONPs on male testicular development have not been clarified. In this study, healthy male C57BL/6 mice received 0, 10, and 25 mg/kg/d CuONPs by oral gavage for 2 weeks (postnatal day 22-35). The testicular weight was decreased, testicular histology was disturbed and the number of Leydig cells was reduced in all CuONPs-exposure groups. Transcriptome profiling suggested steroidogenesis was impaired after exposure to CuONPs. The steroidogenesis-related genes mRNA expression level, concentration of serum steroids hormones and the HSD17B3-, STAR- and CYP11A1-positive Leydig cell numbers were dramatically reduced. In vitro, we exposed TM3 Leydig cells to CuONPs. Bioinformatic analysis, flow cytometry analysis and western blotting analysis confirmed that CuONPs can dramatically reduce Leydig cells viability, enhance apoptosis, trigger cell cycle arrest and reduce cell testosterone levels. U0126 (ERK1/2 inhibitor) significantly reversed TM3 Leydig cells injury and testosterone level decrease induced by CuONPs. These outcomes indicate that CuONPs exposure activates the ERK1/2 signaling pathway, which further promotes apoptosis and cell cycle arrest in TM3 Leydig cells, and ultimately leads to Leydig cells injury and steroidogenesis disorders.

[Exploring the treatment of sepsis-associated acute lung injury with Liangge Powder via ERK1/2 and PI3K/AKT pathways: based on network pharmacology and whole animal experimentation]

Objective: To investigate the therapeutic effect and mechanism of Liangge Powder against sepsis-induced acute lung injury (ALI) . Methods: From April to December 2021, the key components of Liangge Powder and its targets against sepsis-induced ALI were analyzed by network pharmacology, and to enrich for relevant signaling pathways. A total of 90 male Sprague-Dawley rats were randomly assigned to sham-operated group, sepsis-induced ALI model group (model group), Liangge Powder low, medium and high dose group, ten rats in the sham-operated group and 20 rats in each of the remaining four groups. Sepsis-induced ALI model was established by cecal ligation and puncture. Sham-operated group: gavage with 2 ml saline and no surgical treatment. Model group: surgery was performed and 2 ml saline was gavaged. Liangge Powder low, medium and high dose groups: surgery and gavage of Liangge Powder 3.9, 7.8 and 15.6 g/kg, respectively. To measure the wet/dry mass ratio of rats lung tissue and evaluate the permeability of alveolar capillary barrier. Lung tissue were stained with hematoxylin and eosin for histomorphological analysis. The levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL) -6 and IL-1β in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay. The relative protein expression levels of p-phosphatidylinositol 3-kinase (PI3K), p-protein kinase B (AKT), and p-ertracellular regulated protein kinases (ERK) were detected via Western blot analysis. Results: Network pharmacology analysis indicated that 177 active compounds of Liangge Powder were selected. A total of 88 potential targets of Liangge Powder on sepsis-induced ALI were identified. 354 GO terms of Liangge Powder on sepsis-induced ALI and 108 pathways were identified using GO and KEGG analysis. PI3K/AKT signaling pathway was recognized to play an important role for Liangge Powder against sepsis-induced ALI. Compared with the sham-operated group, the lung tissue wet/dry weight ratio of rats in the model group (6.35±0.95) was increased (P<0.001). HE staining showed the destruction of normal structure of lung tissue. The levels of IL-6 [ (392.36±66.83) pg/ml], IL-1β [ (137.11±26.83) pg/ml] and TNF-α [ (238.34±59.36) pg/ml] were increased in the BALF (P<0.001, =0.001, <0.001), and the expression levels of p-PI3K, p-AKT and p-ERK1/2 proteins (1.04±0.15, 0.51±0.04, 2.31±0.41) were increased in lung tissue (P=0.002, 0.003, 0.005). The lung histopathological changes were reduced in each dose group of Liangge Powder compared with the model group. Compared with the model group, the wet/dry weight ratio of lung tissue (4.29±1.26) was reduced in the Liangge Powder medium dose group (P=0.019). TNF-α level [ (147.85±39.05) pg/ml] was reduced (P=0.022), and the relative protein expression levels of p-PI3K (0.37±0.18) and p-ERK1/2 (1.36±0.07) were reduced (P=0.008, 0.017). The wet/dry weight ratio of lung tissue (4.16±0.66) was reduced in the high-dose group (P=0.003). Levels of IL-6, IL-1β and TNF-α[ (187.98±53.28) pg/ml, (92.45±25.39) pg/ml, (129.77±55.94) pg/ml] were reduced (P=0.001, 0.027, 0.018), and relative protein expression levels of p-PI3K, p-AKT and p-ERK1/2 (0.65±0.05, 0.31±0.08, 1.30±0.12) were reduced (P=0.013, 0.018, 0.015) . Conclusion: Liangge Powder has therapeutic effects in rats with sepsis-induced ALI, and the mechanism may be related to the inhibition of ERK1/2 and PI3K/AKT pathway activation in lung tissue.

Elevated expression of myosin VI contributes to breast cancer progression via MAPK/ERK signaling pathway

Breast cancer (BC) is one of the most common malignancies occurring in women worldwide, and its incidence is increasing each year. Accumulating evidence indicated that Myosin VI (MYO6) functions as a gene associated with tumor progression in several cancers. However, the potential role of MYO6 and its underlying mechanisms in the development and progression of BC remains unknown. Herein, we examined the expression levels of MYO6 in BC cells and tissues by western blot and immunohistochemistry. Loss- and gain-of-function investigations in vitro were performed to determine the biological functions of MYO6. And in vivo effects of MYO6 on tumorigenesis were investigated in nude mice. Our findings showed that the expression of MYO6 was up-regulated in breast cancer, and its high expression was correlated with poor prognosis. Further investigation exhibited that silencing the expression of MYO6 significantly inhibited cell proliferation, migration and invasion, whereas overexpression of MYO6 enhanced these abilities in vitro. Also, reduced expression of MYO6 significantly retarded the tumor growth in vivo. Mechanistically, Gene Set Enrichment Analysis (GSEA) revealed that MYO6 was involved in mitogen-activated protein kinase (MAPK) pathway. Moreover, we proved that MYO6 enhanced BC proliferation, migration and invasion via increasing the expression of phosphorylated ERK1/2. Taken together, our findings highlight the role of MYO6 in promoting BC cell progression through MAPK/ERK pathway, suggesting it may be a new potential therapeutic and prognostic target for BC patients.

CCL21/CCR7 Axis Contributes to Trophoblastic Cell Migration and Invasion in Preeclampsia by Affecting the Epithelial Mesenchymal Transition via the ERK1/2 Signaling Pathway

Preeclampsia (PE) is a pregnancy-related disorder that is a leading cause of maternal death. The failure of spiral artery remodeling due to insufficient trophoblast migration and invasion is critical in the pathogenesis of PE. Recently, the CC motif chemokine ligand 21 (CCL21) has been widely linked to cancer cell invasion and migration. However, their potential mechanisms are still unknown. In this study, we found that CCL21 expression was significantly lower in the PE group than that in the control group. In vitro experiments revealed that recombinant CCL21 could promote trophoblast cell epithelial-to-mesenchymal transitions (EMTs) and improve migration and invasion. Furthermore, an inhibitor of the ERK1/2 signaling pathway inhibited the CCL21-induced EMT process. Finally, a PE mouse model was established using the NOS inhibitor L-NAME, and we obtained similar results, with downregulated CCL21 and EMT biomarkers and upregulated CCR7. Taken together, these findings suggest that the CCL21/CCR7 axis influences EMT by activating the ERK1/2 signaling pathway, thereby affecting trophoblast cell migration and invasion, which may play a crucial role in the pathogenesis of PE.

ETEC regulates GPR109A expression in intestinal epithelial cells mediated by inflammatory factors secreted by macrophages

Gut microbes control host immunity and homeostasis, and their abnormal changes are associated with the occurrence and development of diseases. GPR109A is an essential receptor on intestinal epithelial cells and interacts with gut microbes. Moreover, increased Enterotoxigenic Escherichia coli K88 strain colonization promotes GPR109A expression in vivo. This study evaluated the detailed mechanism of pathogenic bacteria promoting GPR109A expression. The results revealed that ETEC K88 indirectly fosters GPR109A expression in intestinal epithelial cells by stimulating the production of IL-1β and TNF-α through macrophages which are mediated by ERK1/2 pathway. The study explains the molecular mechanisms by which the bacteria regulate the homeostasis of the host intestinal gene expression during ETEC infection.

Dyngo-4a Induces Neuroblastoma Cell Differentiation Through The AKT and ERK1/2 Pathway

AIM

The aim of the study is to check whether dyngo-4a can inhibit neuroblastoma (NB) proliferation and induce NB cell differentiation Background: Dynamin plays a role in regulating neurotransmission, signaling pathways, nutrient uptake, and pathogen infection, enhancing cell proliferation, tumor invasion, and metastasis. Studies have reported that dyngo-4a, a dynamin inhibitor, can be used to identify potential biomarkers and promising novel therapeutic targets for cancer treatment.

OBJECTIVE

To our knowledge, no published reports are showing that dynamin inhibitors can reduce NB cell proliferation and induce differentiation. In this study, we report that dyngo-4a can inhibit NB proliferation and induce NB cell differentiation.

METHODS

In this study, mouse neuroblastoma (Neuro-2a) cells were cultured in the presence or absence of dyngo-4a or retinoic acid (RA), or in the presence of both dyngo-4a and RA, or in the presence of sequential administration of dyngo-4a and RA to compare the effects on the inhibition of cell proliferation and effects on neuroblastoma cell differentiation induction. The neural cell markers, Nestin and Tuj 1 (Neuron-specific class III beta-tubulin), were used to demonstrate that the differentiated cells have neuronal cell features. The phosphorylation of Protein Kinase B (AKT), extracellular signalregulated kinases1/2 (ERK1/2), and epidermal growth factor receptor (EGFR) were determined to examine the potential mechanisms of induced differentiation.

RESULTS

Dyngo-4a or RA or dyngo-4a with subsequent RA administration induced Neuro-2a cell differentiation. However, RA with subsequent dyngo-4a administration results in almost total death of the Neuro-2a cells. The differentiation rate induced by dyngo-4a was significantly higher than the rate by RA treatment (72.5 ± 1.4% vs. 52.9 ± 3.1% with neuron features, P<0.05; 39.0 ± 0.8% vs. 29.9 ± 1.8% for axons under light microscopy, p<0.05). The differentiation rate of cells treated with dyngo-4a first, followed by RA, was greater than when they were added together (74.8 ± 3.8% vs. 10.6 ± 3.6%; 45.5 ± 1.6% vs. 12.4 ± 0.6%, p<0.01). Co-administration of dyngo-4a and RA at the same time diminished differentiation efficacy significantly. Dyngo-4a induced Neuro-2a cell differentiation and increased Tuj-1 positive staining by the 6th day post- treatment. Dyngo-4a also inhibited Neuro-2a cell proliferation in a dose-dependent manner. Regarding the mechanism, dyngo-4a treatment showed a significant increase in p-AKT and p-ERK1/2 but not in p-EGFR.

CONCLUSION

At a level comparable to RA, dynamin inhibition with dyngo-4a lowers proliferation and causes differentiation of Neuro-2a mouse NB cells in vitro. The AKT pathway is activated by dynago- 4a, which results in differentiation. The combination of RA with dynago-4a reduces the efficiency of differentiation. The application of dynago-4a followed by RA, on the other hand, enhances the differentiating effect, implying alternative mechanistic roles in the process.

A positive feedback loop of ARF6 activates ERK1/2 signaling pathway via DUSP6 silencing to promote pancreatic cancer progression

ERK1/2 are essential proteins mediating mitogen-activated protein kinase signaling downstream of RAS in pancreatic adenocarcinoma (PDAC). Our previous study reveals that ARF6 plays a positive regulatory role in ERK1/2 pathway in a feedback loop manner. A significant part of the literature on ARF6 has emphasized its oncogenic effect as an essential downstream molecule of ERK1/2, and no research has been done on the regulation mechanisms of the feedback loop between ARF6 and the ERK1/2 signaling pathway. In the present study, we explore the gene network downstream of ARF6 and find that DUSP6 may be the critical signal molecule in the positive feedback loop between ARF6 and ERK1/2. Specifically, to elucidate the negative correlations between ARF6 and DUSP6 in pancreatic cancer, we examine their expressions in pancreatic cancer tissues by immunohistochemical staining. Then the impact of DUSP6 on the proliferation and apoptosis of PDAC cells are investigated by gain-of-function and loss-of-function approaches. Mechanism explorations uncover that ARF6 suppresses the expression of DUSP6, which is responsible for the dephosphorylation of ERK1/2. Altogether, these results indicate that DUSP6 plays a tumor-suppressive role and acts as an intermediate molecule between ARF6 and ERK1/2 in PDAC cells, thereby forming a positive feedback loop.

PCL nanofibrous incorporating unique matrix fusion protein adsorbed mesoporous bioactive glass for bone tissue engineering

Mesoporous bioactive glass (MBG) is a potential biomedical material in bone defect repairment because of its bioactivity, biocompatibility, and osteoinduction properties. Here we report that Mg-doped MBG scaffold with 3:1 Ca/Mg ratio (MBG-Ca/Mg-3) is good for MC3T3-E1 osteoblast differentiation and mineralization. Mimicking bone extracellular matrix structure by electrospinning, we used MBG-Ca/Mg-3 adsorbed with Osteocalcin-Osteopontin-Biglycan (OOB), a new unique matrix fusion protein, to form OOB@MBG-Ca/Mg-3 scaffold, which has multifunctional ability in calvarial bone defect repairment in vivo. Intriguingly, we found that OOB@MBG-Ca/Mg-3 scaffold increases the expression of osteoblastic marker genes, including bone morphogenetic protein (Bmp2), osteopontin (Opn), Osterix, Runx2 through activation of ERK1/2. We concluded that OOB@MBG-Ca/Mg-3 scaffold promotes osteoblast differentiation and mineralization through ERK1/2 pathway and it can also enhance bone formation in vivo, which provides a new biomaterial in bone tissue engineering.

Acute pre-learning stress selectively impairs hippocampus-dependent fear memory consolidation: Behavioral and molecular evidence

Despite compelling evidence that stress or stress-related hormones influence fear memory consolidation processes, the understanding of molecular mechanisms underlying the effects of stress is still fragmentary. The release of corticosterone in response to pre-learning stress exposure has been demonstrated to modulate positively or negatively memory encoding and/or consolidation according to many variables such as stress intensity, the emotional valence of the learned material or the interval between stressful episode and learning experience. Here, we report that contextual but not cued fear memory consolidation was selectively impaired in male mice exposed to a 50 min-period of restraint stress just before the unpaired fear conditioning session. In addition to behavioral impairment, acute stress down-regulated activated/phosphorylated ERK1/2 (pERK1/2) in dorsal hippocampal area CA1 in mice sacrificed 60 min and 9 h after unpaired conditioning. In lateral amygdala, although acute stress by itself increased the level of pERK1/2 it nevertheless blocked the peak of pERK1/2 that was normally observed 15 min after unpaired conditioning. To examine whether stress-induced corticosterone overflow was responsible of these detrimental effects, the corticosterone synthesis inhibitor, metyrapone, was administered 30 min before stress exposure. Metyrapone abrogated the stress-induced contextual fear memory deficits but did not alleviate the effects of stress on pERK1/2 and its downstream target phosphorylated CREB (pCREB) in hippocampus CA1 and lateral amygdala. Collectively, our observations suggest that consolidation of hippocampus-dependent memory and the associated signaling pathway are particularly sensitive to stress. However, behavioral normalization by preventive metyrapone treatment was not accompanied by renormalization of the canonical signaling pathway. A new avenue would be to consider surrogate mechanisms involving proper metyrapone influence on both nongenomic and genomic actions of glucocorticoid receptors.

Quercetin attenuates the cardiotoxicity of doxorubicin-cyclophosphamide regimen and potentiates its chemotherapeutic effect against triple-negative breast cancer

Doxorubicin combined with cyclophosphamide (AC) is the most commonly used regimen for triple-negative breast cancer (TNBC) chemotherapy; however, its clinical application is severely limited by its serious adverse effect on cardiomyocytes. The cardiotoxicity of AC is mainly the result of oxidative stress caused by the imbalance between reactive oxygen species (ROS) and antioxidants, and it also involves multiple signaling pathways. Quercetin (Que) has been proven to possess strong antioxidant activity, and therefore we investigated whether it had potential protective effect against AC-induced cardiotoxicity. Meanwhile, we also evaluated its effect on the antitumor activity of AC. Our in vitro studies showed that Que could attenuate AC-induced cardiotoxicity by inhibiting ROS accumulation and activating ERK1/2 pathway in cardiomyocytes, but interestingly, Que could enhance the antitumor activity of AC by inhibiting ROS accumulation and ERK1/2 pathway in TNBC cells. In addition, our in vivo studies further confirmed that Que could enhance the chemotherapeutic effect of AC against TNBC while it reduced the injury of cardiotoxicity induced by AC. Therefore, Que could be used as a novel agent for the treatment of cardiotoxicity induced by AC regimen in TNBC chemotherapy.

Paeoniflorin ameliorates chronic stress-induced depression-like behavior in mice model by affecting ERK1/2 pathway

Depression is a mental and emotional disorder that has made an opening great burden to the society. Paeoniflorin showed remarkable antidepressant-like effects in multiple animal models with depressive disorders. However, the molecule of paeoniflorin on depression is less studied. This study aims to explore the effect and the molecular mechanism of paeoniflorin on depression in a chronic restraint stress (CRS) mice model. CRS model of C57BL/6 J mice was set up. Sucrose preference test (SPT), tail suspension test (TST), open field test (OFT) and forced swimming test (FST) were used to assess depression symptoms. Immunofluorescence staining, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were implemented to detect the expression changes of the proteins involved in extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway. Results showed that paeoniflorin treatment decreased the degree of depression in the CRS mice. Further analysis showed that the expression of ERK1/2 proteins was significantly downregulated, while paeoniflorin could elevate the expression of ERK1/2 proteins in CRS mice. Finally, it showed that inhibiting signaling ERK1/2 pathway could aggravate the depressive behavior when treatment with ERK-specific inhibitor U0126, while the condition could be partially relieved when treated with paeoniflorin. In conclusion, the present study demonstrated that paeoniflorin attenuated chronic stress-induced depression-like behavior in mice by affecting the ERK1/2 pathway. These findings provided the basis for the molecular mechanism of paeoniflorin on the effect of depression, which support paeoniflorin might act as an important drug in the treatment of depression.

DUSP1 regulates hippocampal damage in epilepsy rats via ERK1/2 pathway

OBJECTIVE

To investigate the effects of DUSP1 on the hippocampal injury of young rats with epilepsy (EP) through mediating ERK1/2 signaling pathway.

METHODS

Young SD rats were selected and divided into Control, EP, EP + LV-GFP, EP + LV-DUSP1, EP + LV-siDUSP1, and EP + LV-siDUSP1 + U0126 groups. Morris Water Maze Test was used to detect the spatial learning and memory. Nissl staining and TUNEL staining were conducted and the inflammatory factors and oxidative stress-related indicators were also measured. Western blotting was utilized to detect the expression of DUSP1 and ERK1/2 pathway. EP cell model was constructed in vitro to verify the in vivo results.

RESULTS

Compared with Control group, young rats in EP group had decreased spatial learning and memory abilities and increased apoptotic rate and decreased number of Nissl positive cells. Besides, the up-regulated levels in inflammatory factors (IL-1β, IL-6), MDA content, and p-ERK1/2/ERK1/2 protein expression, as well as the down-regulated levels in DUSP1 protein expression and SOD content were also observed in EP rats. The EP rats treated with LV-DUSP1 showed obvious improvements regarding the above indicators, while those treated with LV-siDUSP1 had aggravated injury. But the effect of LV-siDUSP1 can be reversed by the treatment with ERK1/2 pathway inhibitor U0126. Further in vitro investigation verified the in vivo results.

CONCLUSION

DUSP1 may ameliorate the oxidative stress and inflammatory injury, as well as improve spatial learning and memory abilities via inhibiting ERK1/2 pathway, eventually playing protective roles in hippocampal injury of young rats with EP.

HSP70 inhibition suppressed glioma cell viability during hypoxia/reoxygenation by inhibiting the ERK1/2 and PI3K/AKT signaling pathways

Heat shock protein 70 (HSP70) can regulate astrocyte viability under hypoxic and ischemic conditions. However, the protective mechanism involved is not completely clear. This study aimed to investigate whether HSP70 protects U87 glioma cells against hypoxic damage via the extracellular signal-regulated kinases 1/2 (ERK1/2) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways. Lentivirus-mediated HSP70-siRNA was used for HSP70 silencing. U87 glioma cells with lentiviral infection were exposed to hypoxia for 4, 8, 12, and 24 h, respectively, followed by a 24-h reoxygenation treatment. A Cell-Counting Kit-8 was then used to evaluate the viability of the U87 glioma cells. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting were performed to determine the mRNA and protein levels, respectively. The expression of HSP70, p-ERK1/2, p-AKT, and U87 cell viability were increased after 8 h of hypoxia/24 h of reoxygenation (P < 0.01). However, HSP70 silencing significantly decreased the U87 cell viability after the hypoxia/reoxygenation treatment (P < 0.01). The protein expressions of p-ERK1/2 and p-AKT also decreased in HSP70-silenced U87 cells (P < 0.01). In conclusion, HSP70 inhibition suppressed the viability of U87 glioma cells during hypoxia/reoxygenation (at least partially) by inhibiting the ERK1/2 and PI3K/AKT signaling pathways. This study may help to understand the molecular mechanisms underlying the progression and development of cerebral hypoxia-ischemia.

Tripartite motif protein 11 (TRIM11), an oncogene for human lung cancer via the DUSP6-mediated ERK1/2 signaling pathway

Evidence suggests that Tripartite Motif Containing 11 (TRIM11) has pro-tumor activity in human non-small cell lung cancer (NSCLC). However, the roles and underlying mechanisms of TRIM11 in NSCLC have not yet been fully elucidated. In this work, human lung cancer cell lines (A549, H446, and H1975) were transfected with siRNA or lentiviruses to knockdown or overexpress TRIM11 and dual-specificity phosphatase 6 (DUSP6). The cell tumor response was assessed by determining the rate of proliferation, apoptosis, the uptake of 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl) amino]-2-deoxyglucose (2-NBDG), and the secretion of lactic acid (LD). Dominant-negative (dn)-MEK1 was used to block the ERK1/2 pathway. The mechanism was investigated by assessing the protein levels of pyruvate kinase isozymes M2 (PKM2) and DUSP6, as well as the activation of ERK1/2 pathway. Our data confirmed the anti-cancer effect of siTRIM11 in human lung cancer by demonstrating inhibition of cancer cell proliferation, induction of apoptosis, prevention of 2-NBDG uptake, suppression of LD production, and prevention of lung cancer cell (A549) tumorigenicity in nude mice. The underlying mechanism involved the up-regulation of DUSP6 and the inhibition of ERK1/2 activity. Overexpression of TRIM11 induced tumorigenesis of NSCLC in vitro, and the activation of ERK1/2 was significantly reversed by DUSP6 overexpression or additional dn-MEK1 treatment. Interestingly, we confirmed TRIM11 as a deubiquitinase that regulated DUSP6 accumulation, indicating that lung cancer progression is regulated via the DUSP6-ERK1/2 pathway. In conclusion, TRIM11 is an oncogene in NSCLC, likely through the DUSP6-mediated ERK1/2 signaling pathway.

STC1 ameliorates cognitive impairment and neuroinflammation of Alzheimer's disease mice via inhibition of ERK1/2 pathway

OBJECTIVE

To investigate the regulatory role of STC1 (Stanniocalcin-1) mediated ERK1/2 pathway in cognitive impairment and neuroinflammation of Alzheimer's disease (AD).

METHODS

WT mice and STC1 Tg mice (transgenic overexpression of STC1) were used to establish AD models to perform behavioral test by Morris water maze. Hippocampal cell apoptosis was quantified by TUNEL staining, the levels of inflammatory cytokines in serum and hippocampal tissues determined by ELISA, as well as oxidative stress-related factors detected by corresponding testing kits, and protein expression of STC1 and ERK1/2 pathway measured by Western blotting.

RESULTS

Compared with WT Sham group, WT AD mice had prolonged escape latency, decreased crossing platform times, increased hippocampal cell apoptosis with up-regulated inflammatory cytokines and oxidative stress-related factors, as well as increased STC1 and ERK1/2 pathway-related molecules. By contrast, STC1 Tg AD mice showed shortened escape latency, increased crossing platform times than WT AD mice, and they also exhibited the decreased apoptosis index and inflammatory cytokines, alleviated oxidative stress-injury, down-regulated protein expression of ERK1/2 pathway, and up-regulated the protein expression of STC1 and UCP2.

CONCLUSION

STC1 overexpression could alleviate oxidative stress-induced injury, reduce neuroinflammation, improve cognitive function to play a neuro-protective role by inhibiting ERK1/2 signaling pathway.

MiR-27a-3p promotes the osteogenic differentiation by activating CRY2/ERK1/2 axis

Background

Osteoporosis seriously disturbs the life of people. Meanwhile, inhibition or weakening of osteogenic differentiation is one of the important factors in the pathogenesis of osteoporosis. It was reported that miR-27a-3p reduced the symptoms of osteoporosis. However, the mechanism by which miR-27a-3p in osteogenic differentiation remains largely unknown.

Methods

To induce the osteogenic differentiation in MC3T3-E1 cells, cells were treated with osteogenic induction medium (OIM). RT-qPCR was used to evaluate the mRNA expression of miR-27a-3p and CRY2 in cells. The protein levels of CRY2, Runt-related transcription factor 2 (Runx2), osteopontin (OPN), osteocalcin (OCN) and the phosphorylation level of extracellular regulated protein kinases (ERK) 1/2 in MC3T3-E1 cells were evaluated by western blotting. Meanwhile, calcium nodules and ALP activity were tested by alizarin red staining and ALP kit, respectively. Luciferase reporter gene assay was used to analyze the correlation between CRY2 and miR-27a-3p.

Results

The expression of miR-27a-3p and the phosphorylation level of ERK1/2 were increased by OIM in MC3T3-E1 cells, while CRY2 expression was decreased. In addition, OIM-induced increase of calcified nodules, ALP content and osteogenesis-related protein expression was significantly reversed by downregulation of miR-27a-3p and overexpression of CRY2. In addition, miR-27a-3p directly targeted CRY2 and negatively regulated CRY2. Meanwhile, the inhibitory effect of miR-27a-3p inhibitor on osteogenic differentiation was reversed by knockdown of CRY2 or using honokiol (ERK1/2 signal activator). Furthermore, miR-27a-3p significantly inhibited the apoptosis of MC3T3-E1 cells treated by OIM. Taken together, miR-27a-3p/CRY2/ERK axis plays an important role in osteoblast differentiation.

Conclusions

MiR-27a-3p promoted osteoblast differentiation via mediation of CRY2/ERK1/2 axis. Thereby, miR-27a-3p might serve as a new target for the treatment of osteoporosis.

Potential Osteoinductive Effects of Hydroxyapatite Nanoparticles on Mesenchymal Stem Cells by Endothelial Cell Interaction

Nano-hydroxyapatite (nano-HA) has attracted substantial attention in the field of regenerative medicine. Endothelial cell (EC)-mesenchymal stem cell (MSC) interactions are necessary for bone reconstruction, but the manner in which nano-HA interacts in this process remains unknown. Herein, we investigated the cytotoxicity and osteoinductive effects of HA nanoparticles (HANPs) on MSCs using an indirect co-culture model mediated by ECs and highlighted the underlying mechanisms. It was found that at a subcytotoxic dose, HANPs increased the viability and expression of osteoblast genes, as well as mineralized nodules and alkaline phosphatase production of MSCs. These phenomena relied on HIF-1α secreted by ECs, which triggered the ERK1/2 signaling cascade. In addition, a two-stage cell-lineage mathematical model was established to quantitatively analyze the impact of HIF-1α on the osteogenic differentiation of MSCs. It demonstrated that HIF-1α exerted a dose-dependent stimulatory effect on the osteogenic differentiation rate of MSCs up to 1500 pg/mL, which was in agreement with the above results. Our data implied that cooperative interactions between HANPs, ECs, and MSCs likely serve to stimulate bone regeneration. Furthermore, the two-stage cell-lineage model is helpful in vitro system for assessing the potential influence of effector molecules in bone tissue engineering.

LncRNA BANCR Attenuates the Killing Capacity of Cisplatin on Gastric Cancer Cell Through the ERK1/2 Pathway

Purpose

Chemotherapy-based comprehensive treatments are the most important therapeutic methods for patients with advanced gastric cancer, but chemoresistance often cause treatment failure. Long non-coding RNA (LncRNA) BRAF-activated non-coding RNA (BANCR) has been shown to participate in many biological behaviors of multiple cancers. However, the biological roles of LncRNA BANCR in chemoresistance of gastric cancer remain unclear. Here, we aimed to evaluate the functions of LncRNA BANCR on the therapy of gastric cancer.

Methods

In this study, LncRNA BANCR expression was detected in gastric cancer patient samples and cell lines by quantity polymerase chain reaction (qPCR). Cell proliferation and viability in cisplatin-treated cells were measured using clonogenic survival assay and cell counting kit-8. The levels of ERK1/2 pathway molecules were tested with Western blot. Ly3214996, an inhibitor of ERK signal pathway, was administered to assess the effects of BANCR overexpression on gastric cancer cell with cisplatin-treated resistance. Moreover, the role of BANCR in cisplatin resistance of gastric cancer was validated in xenograft mouse models in vivo.

Results

Our study revealed that LncRNA BANCR expression was also significantly increased in gastric cancer tissues compared with adjacent normal tissues. Furthermore, we found that BANCR overexpression promoted gastric cancer cell resistance to cisplatin in vitro. Ly3214996 treatment abolished the BANCR overexpression-mediated gastric cancer cell cisplatin resistance via regulating the phosphorylation of ERK protein. Knock-down of BANCR significantly delayed tumor growth in xenograft mouse models.

Conclusion

BANCR promoted cisplatin resistance of gastric cancer cells by activating ERK1/2 pathway. Inhibition of BANCR markedly suppressed the growth of gastric cancer cells in vitro as well as in vivo. These results provided a new strategy for gastric cancer therapy via targeting BANCR.

The 14-3-3σ protein promotes HCC anoikis resistance by inhibiting EGFR degradation and thereby activating the EGFR-dependent ERK1/2 signaling pathway

Resistance to anoikis, cell death due to matrix detachment, is acquired during tumor progression. The 14-3-3σ protein is implicated in the development of chemo- and radiation resistance, indicating a poor prognosis in multiple human cancers. However, its function in anoikis resistance and metastasis in hepatocellular carcinoma (HCC) is currently unknown.

Methods: Protein expression levels of 14-3-3σ were measured in paired HCC and normal tissue samples using western blot and immunohistochemical (IHC) staining. Statistical analysis was performed to evaluate the clinical correlation between 14-3-3σ expression, clinicopathological features, and overall survival. Artificial modulation of 14-3-3σ (downregulation and overexpression) was performed to explore the role of 14-3-3σ in HCC anoikis resistance and tumor metastasis in vitro and in vivo. Association of 14-3-3σ with epidermal growth factor receptor (EGFR) was assayed by co-immunoprecipitation. Effects of ectopic 14-3-3σ expression or knockdown on EGFR signaling, ligand-induced EGFR degradation and ubiquitination were examined using immunoblotting and co-immunoprecipitation, immunofluorescence staining, and flow cytometry analysis. The levels of EGFR ubiquitination, the interaction between EGFR and 14-3-3σ, and the association of EGFR with c-Cbl after EGF stimulation, in 14-3-3σ overexpressing or knockdown cells were examined to elucidate the mechanism by which 14-3-3σ inhibits EGFR degradation. Using gain-of-function or loss-of-function strategies, we further investigated the role of the EGFR signaling pathway and its downstream target machinery in 14-3-3σ-mediated anoikis resistance of HCC cells.

Results: We demonstrated that 14-3-3σ was upregulated in HCC tissues, whereby its overexpression was correlated with aggressive clinicopathological features and a poor prognosis. In vitro and in vivo experiments indicated that 14-3-3σ promoted anoikis resistance and metastasis of HCC cells. Mechanistically, we show that 14-3-3σ can interact with EGFR and significantly inhibit EGF-induced degradation of EGFR, stabilizing the activated receptor, and therefore prolong the activation of EGFR signaling. We demonstrated that 14-3-3σ downregulated ligand-induced EGFR degradation by inhibiting EGFR-c-Cbl association and subsequent c-Cbl-mediated EGFR ubiquitination. We further verified that activation of the ERK1/2 pathway was responsible for 14-3-3σ-mediated anoikis resistance of HCC cells. Moreover, EGFR inactivation could reverse the 14-3-3σ-mediated effects on ERK1/2 phosphorylation and anoikis resistance. Expression of 14-3-3σ and EGFR were found to be positively correlated in human HCC tissues.

Conclusions: Our results indicate that 14-3-3σ plays a pivotal role in the anoikis resistance and metastasis of HCC cells, presumably by inhibiting EGFR degradation and regulating the activation of the EGFR-dependent ERK1/2 pathway. To our best knowledge, this is the first report of the role of 14-3-3σ in the anoikis resistance of HCC cells, offering new research directions for the treatment of metastatic cancer by targeting 14-3-3σ.

DCZ3301, an aryl-guanidino agent, inhibits ocular neovascularization via PI3K/AKT and ERK1/2 signaling pathways

Neovascularization is a critical process in the pathophysiology of neovascular eye diseases. Although anti-VEGF therapy has achieved remarkable curative effects, complications, limited efficacy and drug resistance remain the prominent problems. DCZ3301, an aryl-guanidino compound, was reported to have anti-tumor activity in the previous studies. Here, we demonstrated the effects of DCZ3301 on human umbilical vein endothelial cell (HUVEC) in vitro, and performed choroid microvascular sprouting assay ex vivo and alkali-burn induced corneal neovascularization mouse model in vivo. We found that DCZ3301 inhibited the proliferation, migration, and tube formation of HUVECs, while inducing the spontaneous apoptosis of HUVECs by suppressing the activation of PI3K/AKT and ERK1/2 pathways. Furthermore, DCZ3301 inhibited the choroid microvascular sprouting, diminished the area of corneal neovascularization and attenuated the edema of corneal stroma after alkali burn. Together, these results suggested that DCZ3301 exerted anti-angiogenic properties, and might be regarded as a potential candidate for ocular neovascularization.

Knockdown of TRIM37 Promotes Apoptosis and Suppresses Tumor Growth in Gastric Cancer by Inactivation of the ERK1/2 Pathway

Objective

Gastric cancer (GC), a malignant tumor of the gastric mucosa, is the second leading cause of cancer deaths worldwide. Although the incidence and mortality of gastric cancer have been reduced in the US and elsewhere, it is still a major public health concern. In this study, we attempted to investigate the function of tripartite motif-containing protein 37 (TRIM37) in GC cell lines in order to propose a new therapy for GC.

Methods

The expression of TRIM37 in GC patients and cell lines was detected by immunohistochemistry, real-time PCR and Western blotting analysis. After TRIM37 knockdown or overexpression, the cell cycle, proliferation and apoptosis, as well as the expression of related proteins, were detected. In addition, in vivo experiments on nude mice were performed.

Results

We found that TRIM37 expression was significantly elevated in tumor tissues of GC patients and GC cell lines, and patients with high expression of TRIM37 had a poor prognosis. Knockdown of TRIM37 in GC cells significantly inhibited cell proliferation and cell cycle progression, promoted apoptosis, increased cleaved caspase 3 and decreased c-myc and phosphorylation of protein kinase 1/2 (p-ERK1/2). Effects of TRIM37 overexpression were opposite to that of TRIM37 knockdown and were potently attenuated by an ERK1/2 inhibitor. In addition, an ERK1/2 agonist increased TRIM37 and p-ERK1/2 in a dose-dependent manner, and TRIM37 knockdown potently attenuated EGF-induced cell proliferation and expression of TRIM37 and p-ERK1/2. Interestingly, we found that TRIM37 overexpression did not affect the mRNA level of dual-specificity phosphatase 6 (DUSP6), but reduced its protein level in GC cells. Co-immunoprecipitation (Co-IP) analyses revealed that TRIM37 interacted with DUSP6, and TRIM37 overexpression enhanced DUSP6 ubiquitination in GC cells. In vivo experiments on nude mice showed the inhibitory effect of TRIM37 knockdown on tumor growth.

Conclusion

These findings suggest that TRIM37 may act as an oncogene in the growth of GC cells and illustrate its potential function as a target in the treatment of GC.

Beta defensin 3 enhances ovarian granulosa cell proliferation and migration via ERK1/2 pathway in vitro†

Antimicrobial peptides (AMPs) are regarded as host defense peptides that possess bactericidal activity as well as immunomodulatory function. However, the role of AMP in the mammalian ovary is unknown. In the present study, porcine granulosa cells were utilized in a cell model to study the role of porcine beta defensin 2 (pBD2; pDEFB4B) and 3 (pBD3; pDEFB103A) during ovarian follicular development. Granulosa cells were cultured in the absence and presence of 1, 10, and 50 μg/ml of pDEFB4B or pDEFB103A. After 24 h of treatment, pDEFB103A but not pDEFB4B stimulated granulosa cell proliferation in a concentration-dependent manner (P < 0.05). This effect was dependent on the stage of follicular development. In addition, transwell cell migration assay showed that in the presence of pDEFB103A (10 μg/ml), a 2.5-fold increase in cell migration was achieved. Furthermore, further study revealed that pDEFB103A increased the mRNA levels of cyclin D1 (CCND1) and proliferating cell nuclear antigen (PCNA), both associated with cell proliferation. To study the potential pathway involved in pDEFB103A-induced cell proliferation and migration, western blots were performed. It was found that pDEFB103A significantly increased the phosphorylated-ERK1/2 to nonphosphorylated ratio. Moreover, pretreatment with the U0126, a specific ERK1/2 phosphorylation inhibitor, suppressed PDEFB103A inducing GCs ERK1/2 phosphorylation, as well as proliferation and migration, suggesting that PDEFB103A may act via activating the ERK1/2 pathway. Furthermore, using a signal transduction pathway Elk-1 trans-reporting system, the activation of ERK1/2 pathway by PDEFB103A was further confirmed. Our data suggest that AMP may play a physiological role in the mammalian ovary.

IL-33/ST2 axis promotes the inflammatory response of nasal mucosal epithelial cells through inducing the ERK1/2 pathway

Allergic rhinitis (AR) is a nasal mucosal inflammatory disease mediated by environmental allergens. At present, the relationship between the IL-33/ST2 axis, ERK1/2 pathway and AR progression needs further exploration. In our study, an AR model was constructed in vitro by treating HNEpC cells with Der p1. qRT-PCR was applied to assess the mRNA levels of IL-33, ST2, TNF-α, IL-6, and IL-8. Western blotting was used to measure the protein levels of IL-33, ST2, and the downstream proteins p-ERK1/2, ERK1/2, p-RSK, and RSK. IL-6, IL-8, IL-33, and TNF-α protein levels in cell supernatants were evaluated by ELISA. Flow cytometry was performed to check cell apoptosis of HNEpC in the presence or absence of Der p1. Our results indicate that the relative levels of IL-33, ST2, TNF-α, IL-6, and IL-8 were increased significantly in the AR model group. The above effects were notably reversed after transfection with shIL-33 or shST2. IL-33 stimulation further resulted in the increase in both ST2 and inflammation-associated cytokines, and these effects were restored after shST2 treatment. Also, the levels of inflammatory factors induced by IL-33 stimulation or ST2 overexpression were reversed after applying an ERK1/2 pathway blocker. In conclusion, IL-33/ST2 mediated inflammation of nasal mucosal epithelial cells by inducing the ERK1/2 pathway.

Annexin A1/Formyl Peptide Receptor Pathway Controls Uterine Receptivity to the Blastocyst

Embryo implantation into the uterine wall is a highly modulated, complex process. We previously demonstrated that Annexin A1 (AnxA1), which is a protein secreted by epithelial and inflammatory cells in the uterine microenvironment, controls embryo implantation in vivo. Here, we decipher the effects of recombinant AnxA1 in this phenomenon by using human trophoblast cell (BeWo) spheroids and uterine epithelial cells (Ishikawa; IK). AnxA1-treated IK cells demonstrated greater levels of spheroid adherence and upregulation of the tight junction molecules claudin-1 and zona occludens-1, as well as the glycoprotein mucin-1 (Muc-1). The latter effect of AnxA1 was not mediated through IL-6 secreted from IK cells, a known inducer of Muc-1 expression. Rather, these effects of AnxA1 involved activation of the formyl peptide receptors FPR1 and FPR2, as pharmacological blockade of FPR1 or FPR1/FPR2 abrogated such responses. The downstream actions of AnxA1 were mediated through the ERK1/2 phosphorylation pathway and F-actin polymerization in IK cells, as blockade of ERK1/2 phosphorylation reversed AnxA1-induced Muc-1 and claudin-1 expression. Moreover, FPR2 activation by AnxA1 induced vascular endothelial growth factor (VEGF) secretion by IK cells, and the supernatant of AnxA1-treated IK cells evoked angiogenesis in vitro. In conclusion, these data highlight the role of the AnxA1/FPR1/FPR2 pathway in uterine epithelial control of blastocyst implantation.

Antiapoptotic activity of Chlamydia trachomatis Pgp3 protein involves activation of the ERK1/2 pathway mediated by upregulation of DJ-1 protein

Chlamydia trachomatis has evolved strategies to prevent host cell apoptosis to evade the host immune defense. However, the precise mechanisms of antiapoptotic activity of C. trachomatis still need to be clarified. Pgp3, one of eight plasmid proteins of C. trachomatis, has been identified to be closely associated with chlamydial virulence. In this study, we attempted to explore the effects and the mechanisms of Pgp3 protein on apoptosis in HeLa cells; the results showed that Pgp3 increased Bcl-2/Bax ratio and prevented caspase-3 activation to suppress apoptosis induced by TNF-α and cycloheximide (CHX) through ERK1/2 pathway activation. Downregulation of DJ-1 with siRNA-DJ-1(si-DJ-1) reduced ERK1/2 phosphorylation and elevated apoptotic rate significantly in Pgp3-HeLa cells. However, inhibition of ERK1/2 signal pathway with ERK inhibitor PD98059 had little effect on DJ-1 expression. These findings confirm that plasmid protein Pgp3 contributes to apoptosis resistance through ERK1/2 signal pathway mediated by upregulation of DJ-1 expression. Therefore, the present study provided novel insights into the role of Pgp3 in apoptosis and suggested that manipulation of the host apoptosis response could be a new approach for the prevention and treatment of C. trachomatis infection.

Rap2B knockdown suppresses malignant progression of hepatocellular carcinoma by inactivating the PTEN/PI3K/Akt and ERK1/2 pathways

Rap2B, belonging to the Ras superfamily of small guanosine triphosphate-binding proteins, is upregulated and contributes to the progression of several tumors by acting as an oncogene, including hepatocellular carcinoma (HCC). However, the mechanism underlying the functional roles of Rap2B in HCC remains unclear. In this study, the evaluation of Rap2B expression in HCC cells and tissues was achieved by qRT-PCR and western blot assays. The effects of Rap2B on the malignant biological behaviors in HCC were explored by means of MTT assay, flow cytometry analysis, and Transwell invasion assay, respectively. Protein levels of Ki67, matrix metalloproteinase (MMP)-2, MMP-9, and cleaved caspase-3, together with the alternations of the ERK1/2 and PTEN/PI3K/Akt pathways were qualified by western blot assay. Further verification of the Rap2B function on HCC tumorigenesis was attained by performing in vivo assays. We found that Rap2B levels were upregulated in HCC tissues and cells. Rap2B silencing led to a reduction of cell-proliferative and invasive abilities, and an increase of apoptosis in HCC cells. In addition, xenograft tumor assay demonstrated that Rap2B silencing repressed HCC xenograft tumor growth in vivo. In addition, we found that Rap2B knockdown significantly inhibited the ERK1/2 and PTEN/PI3K/Akt cascades in HCC cells and xenograft tumor tissues. Together, Rap2B knockdown inhibited HCC-malignant progression, which was involved in inhibiting the ERK1/2 and PTEN/PI3K/Akt pathways. Our findings contribute to understanding of the molecular mechanism of Rap2B in HCC progression.

AdipoRon promotes diabetic fracture repair through endochondral ossification-based bone repair by enhancing survival and differentiation of chondrocytes

Diabetic bone defects may exhibit impaired endochondral ossification (ECO) leading to delayed bone repair. AdipoRon, a receptor agonist of adiponectin polymers, can ameliorate diabetes and related complications, as well as overcome the disadvantages of the unstable structure of artificial adiponectin polymers. Here, the effects of AdipoRon on the survival and differentiation of chondrocytes in a diabetic environment were explored focusing on related mechanisms in gene and protein levels. In vivo, AdipoRon was applied to diet-induced-obesity (DIO) mice, a model of obesity and type 2 diabetes, with femoral fracture. Sequential histological evaluations and micro-CT were examined for further verification. We found that AdipoRon could ameliorate cell viability, apoptosis, and reactive oxygen species (ROS) production and promote mRNA expression of chondrogenic markers and cartilaginous matrix production of ATDC5 cells in high glucose medium via activating ERK1/2 pathway. Additionally, DIO mice with intragastric AdipoRon administration had more neocartilage and accelerated new bone formation. These data suggest that AdipoRon could stimulate bone regeneration via ECO in diabetes.

Chlorogenic acid activates ERK1/2 and inhibits proliferation of osteosarcoma cells

Osteosarcoma (OS) is a very aggressive metastatic pediatric and adolescent tumor. Due to its recurrent development of chemotherapy resistance, clinical outcome for OS patients remains poor. Therefore, discovering more effective anticancer agents is needed. Chlorogenic acid (CGA) is a phenolic compound contained in plant-related products that modulates many cellular functions and inhibits cell proliferation in several cancer types. However, few evidence is available in OS. Here, we investigate the effects of CGA in U2OS, Saos-2, and MG-63 OS cells. By multiple approaches, we demonstrate that CGA acts as anticancer molecule affecting the cell cycle and provoking cell growth inhibition mainly by apoptosis induction. We also provide evidence that CGA strongly activates extracellular-signal-regulated kinase1/2 (ERK1/2). Strikingly, ERK1/2 inhibitor PD98059 sensitizes the cells to CGA. Altogether, our data enforce the evidence of the anticancer activity mediated by CGA and provide the rationale for the development of innovative therapeutic strategies in OS cure.

Geraniin inhibits oral cancer cell migration by suppressing matrix metalloproteinase-2 activation through the FAK/Src and ERK pathways

Geraniin has been reported to have numerous biological activities, including antiviral, antihypertensive, antihyperglycaemic, liver protective, antidiabetic, and apoptotic activities. However, the anti-migration effects of geraniin on oral cancer remain elusive. In this study, we revealed the potential antitumor mechanisms of geraniin through the inhibition of the migration and invasion of human oral cancer cell lines SCC-9 and SCC-14. The results of gelatin zymography and Western blot assays revealed that geraniin significantly reduced the activity and expression of matrix metalloproteinase-2 (MMP-2) of oral cancer cells in a concentration-dependent manner. Furthermore, geraniin potently suppressed the phosphorylation of focal adhesion kinase (FAK), Src, and extracellular signal-regulated kinase (ERK)1/2 but did not affect the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase 1/2. Moreover, blocking the MAPK/ERK1/2 pathway significantly enhanced the anti-migration ability of geraniin in oral cancer cells. In conclusion, we demonstrated that geraniin inhibits the motility of SCC-9 and SCC-14 cells in vitro through a molecular mechanism that involves the attenuation of MMP-2 expression and activity mediated by decreased FAK/Src and ERK1/2 pathways.

Circular RNA hsa_circ_0007059 restrains proliferation and epithelial-mesenchymal transition in lung cancer cells via inhibiting microRNA-378

As newly discovered non-coding RNA (ncRNA), circular RNA (circRNA) has become a research hotspot in manifold cancers. But, the influences of hsa_circ_0007059 in lung cancer remain obscure. Expression of hsa_circ_0007059 in lung cancer tissues was firstly determined through RT-qPCR. After overexpressing hsa_circ_0007059, cell viability, apoptosis, p53/CyclinD1, Bax and Pro/Cleaved-Caspase-3 and EMT-correlative factors (E-cadherin, Vimetin, Twist1 and Zeb1) were tested in A549 and H1975 cells. MiR-378 expression in lung cancer tissues and cells was evaluated after miR-378 mimic transfection. Wnt/β-catenin and ERK1/2 pathways were finally evaluated in A549 and H1975 cells. Inhibition of hsa_circ_0007059 was discovered in lung cancer tissues. Overexpressed hsa_circ_0007059 evidently restrained cell proliferation, elevated p53 and repressed CyclinD1 expression, meanwhile triggered apoptosis and enhanced Bax and Cleaved-Caspase-3 expression. Increased hsa_circ_0007059 abated EMT via enhancement of E-cadherin and inhibition of Vimentin, Twist and Zeb1 in A549 and H1975 cells. MiR-378 was up-regulated in lung cancer tissues, declined by hsa_circ_0007059 overexpression in A549 and H1975 cells. Overexpressed hsa_circ_0007059 hindered Wnt/β-catenin and ERK1/2 pathways via suppressing miR-378 in A549 and H1975 cells. The investigations manifested that hsa_circ_0007059 abated cell proliferation and EMT process in lung cancer cells via inactivation of Wnt/β-catenin and ERK1/2 pathways via suppressing miR-378.

Puerarin alleviates liver fibrosis via inhibition of the ERK1/2 signaling pathway in thioacetamide-induced hepatic fibrosis in rats

Liver fibrosis is a complex pathological process and an early step in the progression of liver cirrhosis, which can eventually develop into hepatocellular carcinoma. Currently, there is no effective treatment for liver fibrosis. Puerarin is a traditional Chinese herb, which is commonly used in the treatment of various diseases. In addition, it is also believed to have a therapeutic effect in liver fibrosis. However, whether puerarin reduces liver fibrosis via the ERK1/2 signaling pathway to inhibit the activation of hepatic stellate cell (HSC) and excessive collagen deposition in liver fibrosis remains unknown. The aim of the current study was to establish a liver fibrosis in vivo model by intraperitoneal injection of thioacetamide (TAA) and investigate the effect of puerarin in the treatment of liver fibrosis. Hematoxylin and eosin and Van Gieson's staining were used to examine histopathological changes associated with liver fibrosis. Liver hydroxyproline content was examined to determine the total amount of collagen in the liver. The relative protein expression levels of transforming growth factor β1 (TGFβ1), α-smooth muscle actin (α-SMA), collagen type I, fibronectin, ERK1/2 and p-ERK1/2 were determined by western blot analysis. In the TAA group, histopathological changes and collagen fiber content in rat liver tissue samples were significantly increased compared with the control group (P<0.05). In addition, treatment with puerarin significantly decreased histopathological changes and collagen fiber content in rat liver tissue samples (P<0.05). The relative protein expression levels of TGFβ1, α-SMA, collagen type I, fibronectin and p-ERK1/2 were significantly upregulated in the TAA group compared with the control group (P<0.05), whereas puerarin treatment reversed these changes. These findings suggest that treatment with puerarin may reduce HSC activation and alleviate extracellular matrix protein expression levels by inhibiting the TGF-β/ERK1/2 pathway in liver fibrosis.

The role of the ERK1/2 pathway in simvastatin-loaded nanomicelles and simvastatin in regulating the osteogenic effect in MG63 cells

Objectives

The present study aimed to clarify the role of the ERK1/2 pathway in simvastatin (SV)-loaded nanomicelles (SVNs)- and SV-mediated promotion of cell osteogenic differentiation and explore the molecular mechanisms by which SVNs exhibited a greater efficacy in promoting osteogenic differentiation than SV.

Materials and methods

SVNs were synthesized using a dialysis method. MG63 cells were treated with 2.5, 0.25, and 0.025 μmol/L of the drug. The optimal drug dosage was determined by examining the proliferative activity and ALP activity of the MG63 cells. Subsequently, Western blot analysis was performed to analyze the levels of the phosphorylated ERK1/2 proteins in each experimental group at various time points. Finally, the inhibitor PD98059 was used to effectively inhibit the ERK1/2 pathway. The resulting changes in the proliferative activity of MG63 cells and the osteogenesis-related markers were analyzed.

Results

The SVNs synthesized in the present study had a mean diameter of 27 nm. The encapsulation and drug-loading efficiencies were 52.03% ± 4.05% and 9.42% ± 0.66%, respectively. SVNs and SV exhibited optimum osteogenesis-promoting effects when the drugs were administered at a concentration of 0.25 μmol/L. The drug-induced activation of the ERK1/2 pathway reached a peak at 15 minutes after administration and then declined rapidly. From 24 hours to 7 days, SVNs and SV exerted an inhibitory effect on the ERK1/2 pathway rather than an activating effect. Throughout the whole experimental process, the regulatory effect of SVNs on the ERK1/2 pathway was significantly greater than that of SV. Inhibition of the ERK1/2 pathway by PD98059 markedly reduced the proliferative activity of the cells in all experimental groups. In addition, the ALP activity and the expression levels of the osterix (OSX) and osteocalcin (OC) proteins were drastically increased.

Conclusion

SVNs significantly increased the effect of SV-induced osteogenic differentiation by strongly inhibiting the ERK1/2 pathway.

Improvement of dexamethasone sensitivity by chelation of intracellular Ca2+ in pediatric acute lymphoblastic leukemia cells through the prosurvival kinase ERK1/2 deactivation

Previous studies have demonstrated that glucocorticoid hormones, including dexamethasone, induced alterations in intracellular calcium homeostasis in acute lymphoblastic leukemia (ALL) cells. However, the mechanism by which intracellular calcium homeostasis participates in dexamethasone sensitivity and resistance on ALL cells remains elusive. Here, we found that treatment of cells with dexamethasone resulted in increased intracellular calcium concentrations through store-operated calcium entry stimulation, which was curtailed by store-operated calcium channel blockers. We show that BAPTA-AM, an intracellular Ca2+ chelator, synergistically enhances dexamethasone lethality in two human ALL cell lines and in three primary specimens. This effect correlated with the inhibition of the prosurvival kinase ERK1/2 signaling pathway. Chelating intracellular calcium with Bapta-AM or inhibiting ERK1/2 with PD98059 significantly potentiated dexamethasone-induced mitochondrial membrane potential collapse, reactive oxygen species production, cytochrome c release, caspase-3 activity, and cell death. Moreover, we show that thapsigargin elevates intracellular free calcium ion level, and activates ERK1/2 signaling, resulting in the inhibition of dexamethasone-induced ALL cells apoptosis. Together, these results indicate that calcium-related ERK1/2 signaling pathway contributes to protect cells from dexamethasone sensitivity by limiting mitochondrial apoptotic pathway. This report provides a novel resistance pathway underlying the regulatory effect of dexamethasone on ALL cells.

Biological activities and functional analysis of macrophage migration inhibitory factor in Oncomelania hupensis, the intermediate host of Schistosoma japonicum

Schistosomiasis is a destructive parasitic zoonosis caused by agents of the genus Schistosoma, which afflicts more than 250 million people worldwide. The freshwater amphibious snail Oncomelania hupensis serves as the obligate intermediate host of Schistosoma japonicum. Macrophage migration inhibitory factor (MIF) has been demonstrated to be a pleiotropic immunoregulatory cytokine and a key signaling molecule involved in adaptive and innate immunity. In the present study, we obtained the full-length cDNA of OhMIF and analyzed the characteristics of the ORF and the peptide sequence in O. hupensis. Next we have successfully expressed and purified the recombinant OhMIF protein (rOhMIF) together with a site-directed mutant rOhMIFP2G, in which the N-terminal Proline (Pro2) was substituted by a Gly. Our results indicated that rOhMIF displayed the conserved D-dopachrome tautomerase activity which is dependent on Pro2, and this enzymatic activity can be significantly inhibited by the MIF antagonist ISO-1. Moreover, we also measured and compared the steady state kinetic values for D-dopachrome tautomerase activity of rOhMIF and rHsMIF, and the results showed that the reaction rate, catalytic efficiency and substrate affinity of rOhMIF are significantly lower than those of rHsMIF. Additionally, we also showed that rOhMIF had the oxidoreductase activity which can utilize DTT as reductant to reduce insulin. Furthermore, the results obtained from the in vitro injection assay demonstrated that rOhMIF and its mutant rOhMIFP2G can also induce the phosphorylation and activation of ERK1/2 pathway in O. hupensis circulating hemocytes, indicating that the tautomerase activity is not required for this biological function. These results are expected to produce a better understanding of the internal immune defense system in O. hupensis, and help to further explore the interaction between O. hupensis and its natural parasite S. japoniucm.

IL-17RB enhances thyroid cancer cell invasion and metastasis via ERK1/2 pathway-mediated MMP-9 expression

IL-17RB, a member of the IL-17 receptor family that can be activated by IL-17B, has been proved to be involved in inflammatory diseases and cancers. However, the function of IL-17RB in thyroid cancer is still unknown. In this study, IL-17RB expression in thyroid cancer cell lines and tissues was examined by real-time PCR and western blot. The effects of IL-17RB on cell invasion and migration were determined by in vitro invasion and migration assays, while the effects of IL-17RB on cell metastasis were analyzed by in vivo experiments. The results showed that IL-17RB expression was upregulated in both thyroid cancer cells and tissues. IL-17B dose-dependently promoted the invasion, growth and migration of thyroid cancer cells, whereas knockdown of IL-17RB attenuated the effects of IL-17B in vitro. Moreover, IL-17RB was involved in the metastasis and growth of thyroid cancer cells in vivo. In addition, IL-17RB induced ERK1/2 activation and increased MMP-9 expression in vitro and in vivo. Inhibition of ERK1/2 pathway blocked the IL-17RB-mediated thyroid cancer cell invasion and MMP-9 expression. Together, our findings demonstrate that IL-17RB can enhance thyroid cancer cell invasion and metastasis via ERK1/2 pathway-mediated MMP-9 expression, suggesting that IL-17RB may act as a potential therapeutic target for thyroid cancer therapy.

Downregulation of Talin1 promotes hepatocellular carcinoma progression through activation of the ERK1/2 pathway

Talin1 is an adaptor protein that conjugates integrins to the cytoskeleton and regulates integrins and focal adhesion signaling. Several studies have found that Talin1 is overexpressed in several tumor types and promotes tumor progression. However, the explicit role of Talin1 in hepatocellular carcinoma (HCC) progression is still unclear and its functional mechanism remains largely unknown. In this study, we showed a trend of gradually decreasing expression of Talin1 from normal liver tissues to hepatocirrhosis, liver hyperplasia, the corresponding adjacent non‐tumor, primary HCC, and eventually metastatic foci, indicating that Talin1 may correlate with HCC initiation to progression. Talin1 was significantly downregulated in HCC tissues compared with adjacent non‐tumor tissues and low Talin1 expression was associated with HCC progression and poor prognosis. Furthermore, Talin1 knockdown induced epithelial–mesenchymal transition and promoted migration and invasion in SK‐Hep‐1 cells and HepG2 cells. Mechanistically, we found that the ERK pathway was responsible for these promoting effects of Talin1 knockdown in HCC cells. The promoting effects of Talin1 knockdown on epithelial–mesenchymal transition, migration, and invasion were reversed by U0126, a specific ERK1/2 inhibitor. Taken together, our results suggested that Talin1 might serve as a tumor suppressor in HCC and a potential prognostic biomarker for HCC patients.

Nimbolide suppresses non-small cell lung cancer cell invasion and migration via manipulation of DUSP4 expression and ERK1/2 signaling

Nimbolide plays an important role in treating human diseases. In these years, the anticancer property of nimbolide has been paid more and more attention. However, the role of nimbolide in non-small cell lung cancer (NSCLC) remains unclear. In this study, we found that nimbolide treatment suppressed the invasion and migration of NSCLC cells, in a dose-dependent manner. Moreover, nimbolide treatment dose-dependently inhibited ERK1/2 activation, decreased Snail and MMP-3 expression, and increased E-cadherin expression. Further, we found that nimbolide treatment upregulated DUSP4 expression. DUSP4 knockdown attenuated nimbolide-mediated inhibition of cell invasion, migration and ERK1/2 activation. We also found that DUSP4 knockdown suppressed the effect of nimbolide on MMP-3, Snail and E-cadherin expression. Taken together, our study demonstrates that nimbolide treatment can upregulate the expression of DUSP4, thus inhibiting ERK1/2 activation. Inhibition of ERK1/2 pathway by nimbolide decreases MMP-3 and Snail expression, and increases E-cadherin expression, which finally inhibits NSCLC cell invasion and migration. Therefore, nimbolide may act as a novel drug to inhibit NSCLC invasion and metastasis through manipulation of ERK1/2 signaling and DUSP4 expression.

Protective role of ACE2-Ang-(1-7)-Mas in myocardial fibrosis by downregulating KCa3.1 channel via ERK1/2 pathway

The intermediate-conductance Ca²⁺-activated K⁺ (K_Ca3.1) channel plays a vital role in myocardial fibrosis induced by angiotensin (Ang) II. However, as the antagonists of Ang II, the effect of angiotensin-converting enzyme 2 (ACE2)-angiotensin-(1-7)-Mas axis on K_Ca3.1 channel during myocardial fibrosis remains unknown. This study was designed to explore the function of K_Ca3.1 channel in the cardioprotective role of ACE2-Ang-(1-7)-Mas. Wild-type (WT) mice, hACE2 transgenic mice (Tg), and ACE2 deficiency mice (ACE2^-/-) were administrated with Ang II by osmotic mini-pumps. As the activator of ACE2, diminazene aceturate (DIZE) inhibited increase of blood pressure, collagen deposition, and K_Ca3.1 protein expression in myocardium of WT mice induced by Ang II. In Tg and ACE2^-/- mice, besides the elevation of blood pressure, Ang II induced transformation of cardiac fibroblast into myofibroblast and resulted in augmentation of hydroxyproline concentration and collagen deposition, as well as K_Ca3.1 protein expression, but the changes in ACE2^-/- mice were more obvious than those in Tg mice. Mas antagonist A779 reduced blood pressure, myocardium fibrosis, and myocardium K_Ca3.1 protein expression by Ang II in Tg mice, but activation of K_Ca3.1 with SKA-31 in Tg mice promoted the pro-fibrogenic effects of Ang II. Respectively, in ACE2^-/- mice, TRAM-34, the K_Ca3.1 blocker, and Ang-(1-7) inhibited increase of blood pressure, collagen deposition, and K_Ca3.1 protein expression by Ang II. Moreover, DIZE and Ang-(1-7) depressed p-ERK1/2/t-ERK increases by Ang II in WT mice, and after blockage of ERK1/2 pathway with PD98059, the K_Ca3.1 protein expression was reduced in WT mice. In conclusion, the present study demonstrates that ACE2-Ang-(1-7)-Mas protects the myocardium from hypertension-induced injury, which is related to its inhibiting effect on K_Ca3.1 channels through ERK1/2 pathway. Our results reveal that K_Ca3.1 channel is likely to be a critical target on the ACE2-Ang-(1-7)-Mas axis for its protective role in myocardial fibrosis and changes of K_Ca3.1 induced by homeostasis of ACE-Ang II-AT1 axis and ACE2-Ang-(1-7)-Mas axis may be a new therapeutic target in myocardial fibrosis.

MicroRNA and receptor mediated signaling pathways as potential therapeutic targets in heart failure

INTRODUCTION

Cardiac remodelling is a complex pathogenetic pathway involving genome expression, molecular, cellular, and interstitial changes that cause changes in size, shape and function of the heart after cardiac injury. Areas covered: We will review recent advances in understanding the role of several receptor-mediated signaling pathways and micro-RNAs, in addition to their potential as candidate target pathways in the pathogenesis of heart failure. The myocyte is the main target cell involved in the remodelling process via ischemia, cell necrosis and apoptosis (by means of various receptor pathways), and other mechanisms mediated by micro-RNAs. We will analyze the role of some receptor mediated signaling pathways such as natriuretic peptides, mediators of glycogen synthase kinase 3 and ERK1/2 pathways, beta-adrenergic receptor subtypes and relaxin receptor signaling mechanisms, TNF/TNF receptor family and TWEAK/Fn14 axis, and some micro-RNAs as candidate target pathways in pathogenesis of heart failure. These mediators of receptor-mediated pathways and micro-RNA are the most addressed targets of emerging therapies in modern heart failure treatment strategies. Expert opinion: Future treatment strategies should address mediators involved in multiple steps within heart failure pathogenetic pathways.

Increased production of omega-3 fatty acids protects retinal ganglion cells after optic nerve injury in mice

Injury to the central nervous system causes progressive degeneration of injured axons, leading to loss of the neuronal bodies. Neuronal survival after injury is a prerequisite for successful regeneration of injured axons. In this study, we investigated the effects of increased production of omega-3 fatty acids and elevation of cAMP on retinal ganglion cell (RGC) survival and axonal regeneration after optic nerve (ON) crush injury in adult mice. We found that increased production of omega-3 fatty acids in mice enhanced RGC survival, but not axonal regeneration, over a period of 3 weeks after ON injury. cAMP elevation promoted RGC survival in wild type mice, but no significant difference in cell survival was seen in mice over-producing omega-3 fatty acids and receiving intravitreal injections of CPT-cAMP, suggesting that cAMP elevation protects RGCs after injury but does not potentiate the actions of the omega-3 fatty acids. The observed omega-3 fatty acid-mediated neuroprotection is likely achieved partially through ERK1/2 signaling as inhibition of this pathway by PD98059 hindered, but did not completely block, RGC protection. Our study thus enhances our current understanding of neural repair after CNS injury, including the visual system.

Curcumin reverses benzidine-induced cell proliferation by suppressing ERK1/2 pathway in human bladder cancer T24 cells

Bladder cancer is one of the leading causes of cancer-related death in the world. Prolonged exposure to benzidine is a known cause of bladder cancer. Curcumin has been clinically used in chemoprevention and treatment of cancer. However, it remains unknown whether mitogen-activated protein kinase (MAPK) pathways are involved in curcumin-mediated protection from benzidine-associated promotive effects on bladder cancer. In our study, we found that benzidine increased the proliferation of human bladder cancer T24 cells, triggered transition of the cells from G1 to S phase, elevated the expression of cyclin D1 and proliferating cell nuclear antigen (PCNA) and decreased p21 expression. Meanwhile, exposure of T24 cells to benzidine resulted in activation of extracellular regulated protein kinases 1 and 2 (ERK1/2) pathway as well as activator protein 1 (AP-1) proteins. Treatment with ERK1/2 inhibitor U0126 or curcumin effectively abrogated benzidine-triggered cell proliferation and ERK1/2/AP-1 activation. These results suggested for the first time that curcumin in low concentrations played a protective role in benzidine-induced ERK1/2/AP-1 activation and proliferation of bladder cancer cells, therefore providing new insights into the pathogenesis and chemoprevention of benzidine-associated bladder cancer.

Factor Xa induces pro-inflammatory cytokine expression in RAW 264.7 macrophages via protease-activated receptor-2 activation

Coagulation proteases have been suggested to trigger a diversity of inflammatory responses in addition to their critical role in the coagulation cascade. It has been well established that the inflammatory and coagulation pathways are invariably linked. However, the mechanisms through which coagulation protease factor Xa (FXa) causes inflammation remain unclear. Thus, we assessed the pro-inflammatory effects of FXa in RAW 264.7 macrophages. We show that FXa elicits signal transduction in RAW 264.7 macrophages. FXa-induced signal transduction was dependent on the activation of protease-activated receptor 2 (PAR-2), PAR-2 desensitization but not PAR-1 desensitization abolished FXa-induced ERK1/2 phosphorylation. The PAR-2-dependent cellular effects of FXa led to the expression of pro-inflammatory cytokines IL-6, IL-8, TNF-α and IFN-γ in RAW 264.7 macrophages. Furthermore, a specific inhibitor of the ERK1/2 pathway, U0126, decreased the FXa-induced pro-inflammatory cytokines expression significantly. Taken together, our data indicate that FXa induces PAR-2-dependent pro-inflammatory activity in RAW 264.7 macrophages through the ERK1/2 pathway.

ERK1/2 pathway is involved in renal gluconeogenesis inhibition under conditions of lowered NADPH oxidase activity

The aim of this study was to elucidate the mechanisms involved in the inhibition of renal gluconeogenesis occurring under conditions of lowered activity of NADPH oxidase (Nox), the enzyme considered to be one of the main sources of reactive oxygen species in kidneys. The in vitro experiments were performed on primary cultures of rat renal proximal tubules, with the use of apocynin, a selective Nox inhibitor, and TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a potent superoxide radical scavenger. In the in vivo experiments, Zucker diabetic fatty (ZDF) rats, a well established model of diabetes type 2, were treated with apocynin solution in drinking water. The main in vitro findings are the following: (1) both apocynin and TEMPOL attenuate the rate of gluconeogenesis, inhibiting the step catalyzed by phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme of the process; (2) in the presence of the above-noted compounds the expression of PEPCK and the phosphorylation of transcription factor CREB and ERK1/2 kinases are lowered; (3) both U0126 (MEK inhibitor) and 3-(2-aminoethyl)-5-((4-ethoxyphenyl)methylene)-2,4-thiazolidinedione (ERK inhibitor) diminish the rate of glucose synthesis via mechanisms similar to those of apocynin and TEMPOL. The observed apocynin in vivo effects include: (1) slight attenuation of hyperglycemia; (2) inhibition of renal gluconeogenesis; (3) a decrease in renal PEPCK activity and content. In view of the results summarized above, it can be concluded that: (1) the lowered activity of the ERK1/2 pathway is of importance for the inhibition of renal gluconeogenesis found under conditions of lowered superoxide radical production by Nox; (2) the mechanism of this phenomenon includes decreased PEPCK expression, resulting from diminished activity of transcription factor CREB; (3) apocynin-evoked inhibition of renal gluconeogenesis contributes to the hypoglycemic action of this compound observed in diabetic animals. Thus, the study has delivered some new insights into the recently discussed issue of the usefulness of Nox inhibition as a potential antidiabetic strategy.

A novel pro-inflammatory protein of Streptococcus suis 2 induces the Toll-like receptor 2-dependent expression of pro-inflammatory cytokines in RAW 264.7 macrophages via activation of ERK1/2 pathway

Streptococcus suis 2 is an important swine pathogen and an emergent zoonotic pathogen. Excessive inflammation caused by S. suis is responsible for the high levels of early mortality observed in septic shock-like syndrome cases. However, the mechanisms through which S. suis 2 (SS2) causes excessive inflammation remain unclear. Thus, this study aimed to identify novel pro-inflammatory mediators that play important roles in the development of therapies against SS2 infection. In this study, the novel pro-inflammatory protein HP0459, which was encoded by the SSUSC84_0459 gene, was discovered. The stimulation of RAW 264.7 macrophages with recombinant HP0459 protein induced the expression of pro-inflammatory cytokines (IL-1β, MCP-1 and TNF-α). Compared with the wild-type (WT) strain, the isogenic knockout of HP0459 in SS2 led to reduced production of pro-inflammatory cytokines in RAW264.7 macrophages and in vivo. The pro-inflammatory activity of HP0459 was significantly reduced by an antibody against Toll-like receptor 2 (TLR2) in RAW264.7 macrophages and was lower in TLR2-deficient (TLR2-/-) macrophages than in WT macrophages. Furthermore, specific inhibitors of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathways significantly decreased the HP0459-induced pro-inflammatory cytokine production, and a western blot assay showed that HP0459 stimulation induced the activation of the ERK1/2 pathway. Taken together, our data indicate that HP0459 is a novel pro-inflammatory mediator of SS2 and induces TLR2-dependent pro-inflammatory activity in RAW264.7 macrophages through the ERK1/2 pathway.

Benzidine induces epithelial-mesenchymal transition in human uroepithelial cells through ERK1/2 pathway

Prolonged benzidine exposure is a known cause of urothelial carcinoma (UC). Benzidine-induced epithelial-to-mesenchymal transition (EMT) is critically involved in cell malignant transformation. The role of ERK1/2 in regulating benzidine-triggered EMT has not been investigated. This study was to investigate the regulatory role of ERK1/2 in benzidine-induced EMT. By using wound healing and transwell chamber migration assays, we found that benzidine could increase SV-HUC-1 cells invasion activity, western blotting and Immunofluorescence showed that the expression levels of Snail, β-catenin, Vimentin, and MMP-2 were significantly increased, while, the expression levels of E-cadherin, ZO-1 were decreased. To further demonstrate the mechanism in this process, we found that the phosphorylation of ERK1/2, p38, JNK and AP-1 proteins were significantly enhanced compared to the control group (*P < 0.05). Afterward, treated with MAPK pathways inhibitors, only ERK inhibitor（U0126）could reduce the expression of EMT markers in SV-HUC-1 cells, but not p38 and JNK inhibitor（SB203580, SP600125）, which indicated that benzidine induces the epithelial-mesenchymal transition in human uroepithelial cells through ERK1/2 pathway. Taken together, findings from this study could provide into the molecular mechanisms by which benzidine exerts its bladder-cancer-promoting effect as well as its target intervention.

A Novel SHOC2 Variant in Rasopathy

Rasopathies are a group of genetic disorders caused by germline mutations in multiple genes of the Extracellular signal-Regulated Kinases 1 and 2 (ERK1/2) pathway. The only previously identified missense mutation in SHOC2, a scaffold protein of the ERK1/2 pathway, led to Noonan-like syndrome with loose anagen hair. Here, we report a novel mutation in SHOC2(c.519G>A; p.M173I) that leads to a Rasopathy with clinical features partially overlapping those occurring in Noonan and cardiofaciocutaneous syndromes. Studies to clarify the significance of this SHOC2 variant revealed that the mutant protein has impaired capacity to interact with protein phosphatase 1c (PP1c), leading to insufficient activation of RAF-1 kinase. This SHOC2 variant thus is unable to fully rescue ERK1/2 activity in cells depleted of endogenous SHOC2. We conclude that SHOC2 mutations can cause a spectrum of Rasopathy phenotypes in heterozygous individuals. Importantly, our work suggests that individuals with mild Rasopathy symptoms may be underdiagnosed.

Activation of ERK2 in basolateral amygdala underlies the promoting influence of stress on fear memory and anxiety: influence of midazolam pretreatment

Exposure to emotionally arousing experiences elicits a robust and persistent memory and enhances anxiety. The amygdala complex plays a key role in stress-induced emotional processing and in the fear memory formation. It is well known that ERK activation in the amygdala is a prerequisite for fear memory consolidation. Moreover, stress elevates p-ERK2 levels in several areas of the brain stress circuitry. Therefore, given that the ERK1/2 cascade is activated following stress and that the role of this cascade is critical in the formation of fear memory, the present study investigated the potential involvement of p-ERK2 in amygdala subnuclei in the promoting influence of stress on fear memory formation and on anxiety-like behavior. A robust and persistent ERK2 activation was noted in the Basolateral amygdala (BLA), which was evident at 5min after restraint and lasted at least one day after the stressful experience. Midazolam, a short-acting benzodiazepine ligand, administered prior to stress prevented the increase in the p-ERK2 level in the BLA. Pretreatment with intra-BLA infusion of U0126 (MEK inhibitor), but not into the adjacent central nucleus of the amygdala, attenuated the stress-induced promoting influence on fear memory formation. Finally, U0126 intra-BLA infusion prevented the enhancement of anxiety-like behavior in stressed animals. These findings suggest that the selective ERK2 activation in BLA following stress exposure is an important mechanism for the occurrence of the promoting influence of stress on fear memory and on anxiety-like behavior.

Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway

Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway.