Pro-inflammatory cytokines and environmental stress cause p38 mitogen-activated protein kinase activation by dual phosphorylation on tyrosine and threonine

ERK1/ATF-2 signaling axis contributes to interleukin-1β-induced MMP-3 expression in dermal fibroblasts

Matrix metalloproteinases (MMPs) play a pivotal role in tissue remodeling by degrading the extracellular matrix (ECM) components. This mechanism is implicated in a variety of physiological and pathological cellular processes including wound healing. One of the key proteins involved in this process is the proinflammatory cytokine interleukin-1β (IL-1β, which induces the expression of MMP-3 mRNA and the secretion of MMP-3 protein by dermal fibroblasts. In this study, we first investigated the contribution of activating transcription factor 2 (ATF-2) to IL-1β-induced MMP-3 expression in dermal fibroblasts. Our results showed that in cells transfected with ATF-2 siRNA or treated with the ATF-2 inhibitor SBI-0087702, IL-1β-induced MMP-3 mRNA expression was reduced. We also demonstrated that IL-1β stimulates the phosphorylation of ATF-2. These observations suggest that ATF-2 plays an important role in IL-1β-induced MMP-3 expression. Next, we investigated the role of MAPK signaling in ATF-2 activation. In cells treated with the extracellular signal-regulated kinase (ERK) inhibitor FR180240, as well as in cells transfected with ERK1 and ERK2 siRNAs, IL-1β-induced MMP-3 mRNA expression was reduced. In addition, we showed that IL-1β induced the phosphorylation of ERK1/2. These observations suggest that ERK1 and ERK2 are involved in IL-1β-induced MMP-3 expression. However, ERK1 and ERK2 do seem to play different roles. While the ERK inhibitor FR180204 inhibited IL-1β-induced ATF-2 phosphorylation, only in cells transfected with ERK1 siRNA, but not ERK2 siRNA, IL-1β-induced ATF-2 phosphorylation was reduced. These findings suggest that the ERK1/ATF-2 signaling axis contributes to IL-1β-induced MMP-3 expression in dermal fibroblasts.

Wnt/β-catenin signaling pathway regulates asthma airway remodeling by influencing the expression of c-Myc and cyclin D1 via the p38 MAPK-dependent pathway

Airway remodeling is the main characteristic of asthma; however, the mechanisms underlying this pathophysiological change have not been fully elucidated. Previous studies have indicated that the Wnt/β-catenin and mitogen-activated protein kinase (MAPK) signaling pathway are involved in the development of airway remodeling during asthma. Therefore, the present study established an airway remodeling rat model, after which β-catenin, cyclin D1 and c-Myc protein expressions were analyzed via western blotting in the lung tissue and airway smooth muscle cells (ASMCs) of rats. The mRNA expression of the aforementioned proteins were evaluated via reverse transcription-quantitative PCR. β-catenin, cyclin D1 and c-Myc are core transcription factors and target genes of the Wnt/β-catenin and MAPK signaling pathways. Furthermore, β-catenin, c-Myc and cyclin D1 protein expression were determined following blocking of the p38 MAPK signaling pathway in vitro. The results demonstrated that higher expressions of β-catenin, cyclin D1 and c-Myc were detected in lung tissues and ASMCs in the asthma group compared with the control. Blocking the p38 MAPK signaling pathway with a specific inhibitor SB203580 also downregulated the expressions of β-catenin, cyclin D1 and c-Myc in vitro. Taken together, these results indicated that the Wnt/β-catenin signaling pathway may regulate the process of airway remodeling via the p38 MAPK-dependent pathway.

Resveratrol induces apoptosis of benign prostatic hyperplasia epithelial cell line (BPH-1) through p38 MAPK-FOXO3a pathway

Background

Resveratrol is reported to inhibit the growth of prostate, which is characteristic of benign prostatic hyperplasia (BPH) condition. However, the mechanism remains unclear. This study aimed to identify the effects and probable mechanism of resveratrol on BPH.

Methods

We used the BPH epithelial cell line BPH-1 to investigate the effect of resveratrol. Cells were treated with various concentrations of resveratrol, and its effects on cells viability, apoptosis, ROS accumulation, and cell cycle were assessed. Western blot was used to examine activation of p38 MAPK and protein levels of FOXO3a, Bcl2, Bcl-XL, and caspase3. Cells were also co-treated with the p38 MAPK inhibitor SB203580 or ROS scavenger N-Acetyl-L-cysteine (NAC) to further investigate the mechanism.

Results

Resveratrol treatment inhibited the growth of BPH-1 and increased apoptosis of cells. In addition, levels of phosphorylated p38 MAPK level was elevated and FOXO3a repression was observed. Concomitantly, ROS was accumulated. All of these resveratrol-mediated effects were suppressed by additional treatment with SB203580 or NAC. Resveratrol was also found to induce cell cycle arrest at S phase.

Conclusions

Resveratrol can activate p38 MAPK and repress FOXO3a, thereby causing repression of SOD2, catalase, and increase of ROS accumulation, leading to apoptosis in BPH-1 cells.

Mitochondrial calcium uniporter regulates PGC-1α expression to mediate metabolic reprogramming in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with an increased mortality. Metabolic reprogramming has a critical role in multiple chronic diseases. Lung macrophages expressing the mitochondrial calcium uniporter (MCU) have a critical role in fibrotic repair, but the contribution of MCU in macrophage metabolism is not known. Here, we show that MCU regulates peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and metabolic reprogramming to fatty acid oxidation (FAO) in macrophages. MCU regulated PGC-1α expression by increasing the phosphorylation of ATF-2 by the p38 MAPK in a redox-dependent manner. The expression and activation of PGC-1α via the p38 MAPK was regulated by MCU-mediated mitochondrial calcium uptake, which is linked to increased mitochondrial ROS (mtROS) production. Mice harboring a conditional expression of dominant-negative MCU in macrophages had a marked reduction in mtROS and FAO and were protected from pulmonary fibrosis. Moreover, IPF lung macrophages had evidence of increased MCU and mitochondrial calcium, increased phosphorylation of ATF2 and p38, as well as increased expression of PGC-1α. These observations suggest that macrophage MCU-mediated metabolic reprogramming contributes to fibrotic repair after lung injury.

Alternative ZAP70-p38 signals prime a classical p38 pathway through LAT and SOS to support regulatory T cell differentiation

T cell receptor (TCR) stimulation activates diverse kinase pathways, which include the mitogen-activated protein kinases (MAPKs) ERK and p38, the phosphoinositide 3-kinases (PI3Ks), and the kinase mTOR. Although TCR stimulation activates the p38 pathway through a "classical" MAPK cascade that is mediated by the adaptor protein LAT, it also stimulates an "alternative" pathway in which p38 is activated by the kinase ZAP70. Here, we used dual-parameter, phosphoflow cytometry and in silico computation to investigate how both classical and alternative p38 pathways contribute to T cell activation. We found that basal ZAP70 activation in resting T cell lines reduced the threshold ("primed") TCR-stimulated activation of the classical p38 pathway. Classical p38 signals were reduced after T cell-specific deletion of the guanine nucleotide exchange factors Sos1 and Sos2, which are essential LAT signalosome components. As a consequence of Sos1/2 deficiency, production of the cytokine IL-2 was impaired, differentiation into regulatory T cells was reduced, and the autoimmune disease EAE was exacerbated in mice. These data suggest that the classical and alternative p38 activation pathways exist to generate immune balance.

The role of proteasome activity for activating and inhibitory signalling in human platelets

Platelets express key proteins of the proteasome system, but its functional role in the regulation of platelet integrity, however, is not fully understood yet. Therefore, this study evaluated activating and inhibitory platelet signalling pathways using the potent and selective proteasome inhibitor bortezomib. In washed platelets, the effect of bortezomib on viability and on aggregation was assessed. In addition, fibrinogen binding and CD62P expression were determined. The influence on activating and inhibitory signalling was detected by phosphorylation levels of essential messenger molecules. Platelet viability was maintained after incubation with 0.01 μM to 1 μM bortezomib, but tampered with 100 μM bortezomib. Agonist-induced aggregation was only reduced under 100 μM bortezomib and with weak induction by 10 μM adenosine diphosphate. Similarly, phosphorylated kinase levels of the activating signalling pathways were not affected by 0.01 μM to 1 μM bortezomib. In contrast, proteasome inhibition resulted in the reduction of inhibitor-induced vasodilator-stimulated phosphoprotein phosphorylation, accompanied with the partial decrease of induced inhibition of fibrinogen binding and CD62P expression. In conclusion, platelet activation and aggregation are not dependent on proteasome activity. Instead, inhibitory signalling is partially attenuated under proteasome inhibition. Supramaximal inhibitory concentrations of bortezomib (above 1 μM) lead to heterogeneous effects on activating or inhibitory systems, probably caused by decreasing platelet viability.

A temperature-dependent conformational shift in p38α MAPK substrate-binding region associated with changes in substrate phosphorylation profile

Febrile-range hyperthermia worsens and hypothermia mitigates lung injury, and temperature dependence of lung injury is blunted by inhibitors of p38 mitogen-activated protein kinase (MAPK). Of the two predominant p38 isoforms, p38α is proinflammatory and p38β is cytoprotective. Here, we analyzed the temperature dependence of p38 MAPK activation, substrate interaction, and tertiary structure. Incubating HeLa cells at 39.5 °C stimulated modest p38 activation, but did not alter tumor necrosis factor-α (TNFα)-induced p38 activation. In in vitro kinase assays containing activated p38α and MAPK-activated kinase-2 (MK2), MK2 phosphorylation was 14.5-fold greater at 39.5 °C than at 33 °C. By comparison, we observed only 3.1- and 1.9-fold differences for activating transcription factor-2 (ATF2) and signal transducer and activator of transcription-1α (STAT1α) and a 7.7-fold difference for p38β phosphorylation of MK2. The temperature dependence of p38α:substrate binding affinity, as measured by surface plasmon resonance, paralleled substrate phosphorylation. Hydrogen-deuterium exchange MS (HDX-MS) of p38α performed at 33, 37, and 39.5 °C indicated temperature-dependent conformational changes in an α helix near the common docking and glutamate:aspartate substrate-binding domains at the known binding site for MK2. In contrast, HDX-MS analysis of p38β did not detect significant temperature-dependent conformational changes in this region. We observed no conformational changes in the catalytic domain of either isoform and no corresponding temperature dependence in the C-terminal p38α-interacting region of MK2. Because MK2 participates in the pathogenesis of lung injury, the observed changes in the structure and function of proinflammatory p38α may contribute to the temperature dependence of acute lung injury.

COL1A2 is a TBX3 target that mediates its impact on fibrosarcoma and chondrosarcoma cell migration

The developmentally important T-box transcription factor TBX3, is overexpressed in several cancers and contributes to tumorigenesis as either a tumour promoter or tumour suppressor. For example, TBX3 promotes cell proliferation, migration and invasion of chondrosarcoma cells but inhibits these processes in fibrosarcoma cells. This suggests that the cellular context influences TBX3 oncogenic functions, but the mechanism(s) involved has not been elucidated. COL1A2 encodes type I collagen and, like TBX3, plays important roles during embryogenesis and can act as either oncogene or tumour suppressor. Here we explore the possibility that COL1A2 may be a TBX3 target gene responsible for mediating its opposing oncogenic roles in chondrosarcoma and fibrosarcoma cells. Results from qRT-PCR, western blotting, luciferase reporter and chromatin immunoprecipitation assays show that TBX3 binds and activates the COL1A2 promoter. Furthermore, we show that TBX3 levels are regulated by AKT1 and that pseudo-phosphorylation of TBX3 at an AKT consensus serine site, enhances its ability to activate COL1A2. Importantly, we demonstrate that COL1A2 mediates the pro- and anti-migratory effects of TBX3 in chondrosarcoma and fibrosarcoma cells respectively. Our data reveal that the AKT1/TBX3/COL1A2 axis plays an important role in sarcomagenesis.

Enhancement of oxaliplatin-induced colon cancer cell apoptosis by alantolactone, a natural product inducer of ROS

Colon cancer is a malignant type of cancer with high prevalence and is one of the primary causes of cancer-related deaths. Oxaliplatin plays a significant role in the treatment of cancer, but the application of oxaliplatin is restricted due to its toxic side effects and drug resistance in clinical practice. Therefore, there is an urgent need for new strategies that can synergize with oxaliplatin for confronting colon cancer. Alantolactone (ALT), a natural sesquiterpene lactone, possesses antitumor properties in a number of cancer cell lines. In the present study, we investigated how ALT acts synergistically with oxaliplatin on human colorectal cancer HCT116 and RKO cells in vitro and in vivo. We observed that ALT strengthened the effect of oxaliplatin-induced growth restrain and apoptosis in HCT116 and RKO cells. It is through a mechanism concerning remarkable accumulation of intracellular reactive oxygen species (ROS) and activation of JNK and p38 MAPK signaling pathways. These changes ultimately induced apoptosis of HCT116 and RKO cells. Pretreatment of cells with the ROS reversal agent NAC significantly blocked the apoptosis induced by the combination treatment, and suppressed expression of JNK and p38 phosphorylation in HCT116 and RKO cells. In the xenograft model, the combination therapy displayed stronger antitumor activity compared with single agents. Immunohistochemistry of subsequent treatment tumors showed a significant decrease in proliferation as compared to either of the treatments alone. These results suggest that the combination treatment with ALT and oxaliplatin may become a potential therapeutic strategy for colon cancer.

The MAPK Pathway-Based Drug Therapeutic Targets in Pituitary Adenomas

Mitogen-activated protein kinases (MAPKs) include ERK, p38, and JNK MAPK subfamilies, which are crucial regulators of cellular physiology, cell pathology, and many diseases including cancers. For the MAPK signaling system in pituitary adenomas (PAs), the activation of ERK signaling is generally thought to promote cell proliferation and growth; whereas the activations of p38 and JNK signaling are generally thought to promote cell apoptosis. The role of MAPK in treatment of PAs is demonstrated through the effects of currently used medications such as somatostatin analogs such as SOM230 and OCT, dopamine agonists such as cabergoline and bromocriptine, and retinoic acid which inhibit the MAPK pathway. Further, there are potential novel therapies based on putative molecular targets of the MAPK pathway, including 18beta-glycyrrhetinic acid (GA), dopamine-somatostatin chimeric compound (BIM-23A760), ursolic acid (UA), fulvestrant, Raf kinase inhibitory protein (RKIP), epidermal growth factor pathway substrate number 8 (Eps8), transmembrane protein with EGF-like and two follistatin-like domains (TMEFF2), cold inducible RNA-binding protein (CIRP), miR-16, and mammaliansterile-20-like kinase (MST4). The combined use of ERK inhibitor (e.g., SOM230, OCT, or dopamine) plus p38 activator (e.g., cabergoline, bromocriptine, and fulvestrant) and/or JNK activator (e.g., UA), or the development of single drug (e.g., BIM-23A760) to target both ERK and p38 or JNK pathways, might produce better anti-tumor effects on PAs. This article reviews the advances in understanding the role of MAPK signaling in pituitary tumorigenesis, and the MAPK pathway-based potential therapeutic drugs for PAs.

Rosiglitazone Improves Glucocorticoid Resistance in a Sudden Sensorineural Hearing Loss by Promoting MAP Kinase Phosphatase-1 Expression

In this study, we investigated the role of MAP kinase phosphatase-1 (MKP-1) and rosiglitazone (RSG) in glucocorticoid resistance and glucocorticoid sensitivity, respectively, using a guinea pig model of lipopolysaccharide- (LPS-) induced sudden sensorineural hearing loss (SSHL). The pigs were divided into control, LPS, LPS+dexamethasone (DEX), LPS+RSG, and LPS+DEX+RSG groups. Their hearing was screened by auditory brainstem response measurement. Immunofluorescence staining was used to identify the location of MKP-1 in the inner ear. The expression levels of MKP-1 and the related proteins in the inner ear were detected using western blotting. The morphological changes in the cochlea were observed via hematoxylin-eosin staining. Severe hearing loss was observed in the LPS group, as opposed to the protection from hearing loss observed in the LPS+DEX+RSG group. A positive correlation was observed between MKP-1 expression levels and protection from hearing loss. RSG and DEX synergistically influenced inner ear inflammation. In conclusion, resistance of LPS-induced SSHL guinea pig models to glucocorticoids may result from impaired MKP-1 function in inner ear tissues, induced by glucocorticoids, impairing the inhibition of inflammation. Our findings present novel targets to develop potential therapeutics to treat inflammatory diseases of the inner ear.

Inactivation of Cyclic AMP Response Element Transcription Caused by Constitutive p38 Activation Is Mediated by Hyperphosphorylation-Dependent CRTC2 Nucleocytoplasmic Transport

The p38 signal transduction pathway can be activated transiently or constitutively, depending on the contexts in which the activation occurs. However, the biological consequence of constitutive activation of p38 is largely unknown. After screening 300 transcriptional cofactors, we identified CRTC2 as a downstream substrate of constitutively activated p38. Constitutive, rather than transient, activation of p38 led to hyperphosphorylation of CRTC2, resulting in CRTC2 cytosolic relocation and subsequent inactivation of cyclic AMP response element (CRE)-mediated transcription. Interestingly, the cytosolic translocation of CRTC2 depended on phosphorylation accumulation at multiple sites (≥11 phosphoserine/phosphothreonine residues) but not on specific sites. The hyperphosphorylation-driven nucleocytoplasmic transport of CRTC2 may not be a rare case of nuclear export of proteins, as we also observed that constitutively activated p38 promoted FOS nuclear export in a hyperphosphorylation-dependent manner. Collectively, our study uncovered a previously unknown mechanism of inactivation of selected transcription, which results from hyperphosphorylation-driven nucleocytoplasmic transport of cofactors or transcription factors mediated by constitutively active kinase.

Two novel MKKs (MKK4 and MKK7) from Ctenopharyngodon idella are involved in the intestinal immune response to bacterial muramyl dipeptide challenge

Mitogen-activated protein kinase kinases (MKKs) are a class of evolutionarily conserved signalling intermediates of the MAPK signalling pathway that can be activated by a diverse range of pathogenic stimuli and are crucial for the regulation of host immune defence. In this study, two fish MKK genes (CiMKK4 and CiMKK7) were first identified and characterized from grass carp (Ctenopharyngodon idella). Similar to other reported MKKs, the present CiMKK4 and CiMKK7 contained a conserved serine/threonine protein kinase (S_TKc) domain and a canonical dual phosphorylation motif. Quantitative real-time PCR results showed that CiMKK4 and CiMKK7 were broadly transcribed in all selected tissues and developmental stages of grass carp. The mRNA expression levels of CiMKK4 and CiMKK7 in the intestine were significantly induced by bacterial muramyl dipeptide (MDP) challenge in a time-dependent manner (P < 0.01). Additionally, the stimulatory effects of bacterial MDP on CiMKK4 and CiMKK7 expression in the intestine were inhibited by the bioactive dipeptide β-alanyl-l-histidine (carnosine) and alanyl-glutamine (Ala-Gln) (P < 0.05). Moreover, overexpression analysis revealed that CiMKK4 and CiMKK7 were localized throughout the entire cell and could significantly enhance AP-1 reporter gene activation in HEK293T cells. Taken together, these results provide the first experimental demonstration that CiMKK4 and CiMKK7 are involved in the intestinal immune response to MDP challenge in C. idella, which may provide new insight into the bacterial-induced intestinal inflammation of bony fishes.

Cardiac-Specific Cre Induces Age-Dependent Dilated Cardiomyopathy (DCM) in Mice

The genetic modification of the mouse genome using the cre-lox system has been an invaluable tool in deciphering gene and protein function in a temporal and/or spatial manner. However, it has its pitfalls, as researchers have shown that the unregulated expression of cre recombinase can cause DNA damage, the consequences of which can be very detrimental to mouse health. Previously published literature on the most utilized cardiac-specific cre, αMHC-cre, mouse model exhibited a nonlethal hypertrophic cardiomyopathy (HCM) with aging. However, using the same αMHC-cre mice, we observed a cardiac pathology, resulting in complete lethality by 11 months of age. Echocardiography and histology revealed that the αMHC-cre mice were displaying symptoms of dilated cardiomyopathy (DCM) by seven months of age, which ultimately led to their demise in the absence of any HCM at any age. Molecular analysis showed that this phenotype was associated with the DNA damage response through the downregulation of activated p38 and increased expression of JNK, p53, and Bax, known inducers of myocyte death resulting in fibrosis. Our data urges strong caution when interpreting the phenotypic impact of gene responses using αMHC-cre mice, since a lethal DCM was induced by the cre driver in an age-dependent manner in this commonly utilized model system.

Physalactone and 4β-Hydroxywithanolide E Isolated from Physalis peruviana Inhibit LPS-Induced Expression of COX-2 and iNOS Accompanied by Abatement of Akt and STAT1

In previous studies, withanolides isolated from Physalis peruviana were found to exhibit anti-inflammatory potential by suppressing nitrite production induced by lipopolysaccharide (LPS) treatment. Currently, we selected two of the most potent compounds, 4β-hydroxywithanolide E (1) and physalactone (2), to examine the underlying mechanism of action. With LPS-stimulated RAW 264.7 cells in culture, the compounds inhibited the mRNA and protein expression of iNOS and COX-2. To determine which upstream signaling proteins were involved in these effects, phosphorylation levels of three mitogen-activated protein kinases (MAPKs) including ERK1/2, JNK1/2, and p38, were examined, but found unaffected. Similarly, the degradation of IκBα was not attenuated by the compounds. However, phosphorylation of Akt at the Ser-473 residue was inhibited, as was the phosphorylation of STAT1. Interestingly, the compounds also reduced the protein level of total STAT1, possibly by ubiquitin-dependent protein degradation. In sum, these results indicate the potential of 1 and 2 to mediate anti-inflammatory effects through the unexpected mechanism of inhibiting the transcription of iNOS and COX-2 via Akt- and STAT1-related signaling pathways.

Identification of eupatilin and ginkgolide B as p38 ligands from medicinal herbs by surface plasmon resonance biosensor-based active ingredients recognition system

Screening of bioactive ligands for a certain protein target from medicinal herbs is a highly important yet challenging task during drug discovery process. In this study, a surface plasmon resonance biosensor-based active ingredient recognition system (SPR-AIRS) was applied to screen p38 mitogen-activated protein kinase (p38) ligands from herbal extracts. After p38 protein was immobilized on a SPR chip and the suitability of SPR-AIRS was validated, thirty-four p38-related medicinal herbs were selected and pre-screened. Two medicinal herbs having high response signal with p38-immobilized chip, Folium Ginkgo and Herba Artemisiae Scopariae, were injected into SPR system for ligand fishing. Among them, two active compounds, eupatilin (EPT) and ginkgolide B (GKB), were identified as p38 ligands, and then the K_D values of EPT and GKB were measured as 21.68 ± 2.21 and 44.71 ± 1.80 μM, respectively. They can inhibit p38 activities significantly and bind to the ATP binding site on p38. Furthermore, EPT and GKB can inhibit cell proliferation (IC₅₀ = 30.31 ± 6.84 and 42.97 ± 0.83 μM), induce apoptosis and G2/M cell cycle arrest against K562 cell line. This is the first time that EPT and GKB are reported as effective p38 binding ligands. These results prove that SPR-AIRS could be an effective method to screen active compounds acting on a specific protein from complex systems.

Macrophage Migration Inhibitor Promoted the Intrahepatic Bile Duct Injury in Rats with Severe Acute Pancreatitis

BACKGROUND

Macrophage migration inhibitory factor (MIF) is involved in many acute and chronic inflammatory diseases. However, its role in intrahepatic bile duct (IBD) cell damage associated with severe acute pancreatitis (SAP) remains unclear.

AIMS

This study was aimed to identify the role of MIF and its underlying mechanisms in SAP complicated by IBD cell damage.

METHODS

Forty-eight specific-pathogen-free male Wistar rats were randomly divided into four groups (N = 12): a sham operation group (SO group) and three SAP model groups (SAP-3h, SAP-6h, and SAP-12h). Immunohistochemistry was used to detect the expression of MIF and P38 in IBD cells. MIF mRNA expression in IBD cells was observed using real-time fluorescent quantitative polymerase chain reaction (real-time PCR). In addition, Western blotting was performed to detect the protein expression of P38, phosphorylated P38 (P-P38), nuclear factor-κB (NF-κB p65), and tumor necrosis factor alpha (TNF-α). Enzyme-linked immunosorbent assays were used to analyze the levels of TNF-α, IL-1β, and IL-6 in the IBD of rats.

RESULTS

Compared with the SO group, the expression of MIF in the IBD was significantly upregulated both at mRNA and at protein levels in the SAP group. Besides, the protein expression levels of P38, P-P38, NF-κB, p65, TNF-α, IL-1β, and IL-6 in the IBD in rats were also significantly increased in the SAP group and the levels increased gradually as acute pancreatitis progressed (all P < 0.05).

CONCLUSIONS

MIF may promote the IBD injury and inflammatory reaction in SAP via activating the P38-MAPK and NF-κB signaling pathways.

CircSETD3 (Hsa_circ_0000567) acts as a sponge for microRNA-421 inhibiting hepatocellular carcinoma growth

Background

Circular RNAs (circRNAs) play important roles in tumourigenesis and tumour progression. However, the expression profiles and functions of circRNAs in hepatocellular carcinoma (HCC) are largely unclear.

Methods

The expression profiles of circRNAs in HCC were identified through microarray analysis and were validated through quantitative reverse transcription polymerase chain reaction (qRT-PCR). Survival curves were plotted using the Kaplan-Meier method and compared using the log-rank test. The circular structure of candidate circRNA was confirmed through Sanger sequencing, divergent primer PCR, and RNase R treatments. Proliferation of HCC cells was evaluated in vitro and in vivo. The microRNA (miRNA) sponge mechanism of circRNAs was demonstrated using dual-luciferase reporter and RNA immunoprecipitation assays.

Results

CircSETD3 (hsa_circRNA_0000567/hsa_circRNA_101436) was significantly downregulated in HCC tissues and cell lines. Low expression of circSETD3 in HCC tissues significantly predicted an unfavourable prognosis and was correlated with larger tumour size and poor differentiation of HCC in patients. In vitro experiments showed that circSETD3 inhibited the proliferation of HCC cells and induced G1/S arrest in HCC cells. In vivo studies revealed that circSETD3 was stably overexpressed in a xenograft mouse model and inhibited the growth of HCC. Furthermore, we demonstrated that circSETD3 acts as a sponge for miR-421 and verified that mitogen-activated protein kinase (MAPK)14 is a novel target of miR-421.

Conclusion

CircSETD3 is a novel tumour suppressor of HCC and is a valuable prognostic biomarker. Moreover, circSETD3 inhibits the growth of HCC partly through the circSETD3/miR-421/MAPK14 pathway.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1041-2) contains supplementary material, which is available to authorized users.

Anti-inflammatory Effects of Gossypol on Human Lymphocytic Jurkat Cells via Regulation of MAPK Signaling and Cell Cycle

Gossypol, a natural polyphenolic compound extracted from cottonseed oil, has been reported to possess pharmacological properties via modulation cell cycle and immune signaling pathway. However, whether gossypol has anti-inflammatory effects against phytohemagglutinin (PHA)-induced cytokine secretion in T lymphocytes through similar mechanism remains unclear. Using the T lymphocytes Jurkat cell line, we found that PHA exposure caused dramatic increase in interleukin-2 (IL-2) mRNA expression as well as IL-2 secretion. All of these PHA-stimulated reactions were attenuated in a dose-dependent manner by being pretreated with gossypol. However, gossypol did not show any in vitro cytotoxic effect at doses of 5-20 μM. As a possible mechanism underlying gossypol action, such as pronounced suppression IL-2 release, robust decreased PHA-induced phosphorylation of p38 and c-Jun N-terminal kinase expressions was found with gossypol pretreatment, but not significant phosphorylation of extracellular signal-regulated kinase expression. Furthermore, gossypol could suppress the Jurkat cells' growth, which was associated with increased percentage of G1/S phase and decreased fraction of G2 phase in flow cytometry test. We conclude that gossypol exerts anti-inflammatory effects probably through partial attenuation of mitogen-activated protein kinase (phosphorylated JNK and p38) signaling and cell cycle arrest in Jurkat cells.

Inactive Tlk associating with Tak1 increases p38 MAPK activity to prolong the G2 phase

To guard genome integrity, response mechanisms coordinately execute the G2/M checkpoint in responding to stress. p38 MAPK is activated to prolong the G2 phase for completion of damage repair. Tlk activity is required for DNA repair, chromosome segregation and G2 recovery. However, the involvement of Tlk in G2 recovery differs from previous findings that Tlk overexpression delays the G2/M transition. To clarify this difference, genetic interaction experiments were performed using the second mitotic wave as model system. The results indicate that Tlk overexpression prolongs the G2 phase through p38 MAPK activation, independent of Tlk kinase activity. The results of co-immunoprecipitation, database search and RNAi screening suggest that eEF1α1 and Hsc70-5 links Tlk to Tak1. Reduced gene activities of Tlk, Hsc70-5, eEF1α1 and/or Tak1 couldn’t prolong the G2 phase induced by heat shock, indicating that these proteins work together to elevate p38 MAPK activity. In contrast, a high level of wild type Tlk decreases phosphorylated p38 MAPK levels. Thus, the difference is explained by a dual function of Tlk. When under stress, inactive Tlk increases p38 MAPK activity to prolong the G2 phase, and then activated Tlk modulates activities of p38 MAPK and Asf1 to promote G2 recovery afterwards.

P38 is involved in immune response by regulating inflammatory cytokine expressions in the Pacific oyster Crassostrea gigas

P38 mitogen-activated protein kinases are serine/threonine protein kinases reportedly involved in the innate immunity of vertebrates and invertebrates. In the present study, a P38 homolog (CgP38) was characterized from the Pacific oyster Crassostrea gigas. The full-length cDNA of CgP38 was of 1515 bp containing a 1101 bp open reading frame. A serine/threonine protein kinase (S_TKc) domain with a conserved Thr-Gly-Tyr motif and an ATRW substrate-binding site was found in the deduced amino acid sequence of CgP38. CgP38 shared a close evolutionary relationship with ChP38 from the Hong Kong oyster Crassostrea hongkongensis. The transcript levels of CgP38 in hemocytes increased significantly from 12 h to 48 h after lipopolysaccharide (LPS) stimulation and from 12 h to 24 h after Vibrio splendidus stimulation. The phosphorylation level of CgP38 in oyster hemocytes increased significantly at 2 h after LPS stimulation. CgP38 positively regulated the expression of interleukins, such as CgIL17-1, CgIL17-2, CgIL17-3, CgIL17-4 and CgIL17-6, and tumor necrosis factor CgTNF after LPS or V. splendidus stimulation. These results suggested that CgP38 participated in oyster immune response by regulating the expressions of inflammatory cytokines.

Inhibition of macrophage migration inhibitory factor attenuates inflammation and fetal kidney injury in a rat model of acute pancreatitis in pregnancy

Acute pancreatitis in pregnancy (APIP) is a severe disease during pregnancy that mostly occurs during the third trimester. It can lead to additional complications including preterm delivery and high fetal mortality. In this study, we investigated the protective effects of (S, R)-3-(4-hydroxyphenyl)-4, 5dihydro-5-isoxazole acetic methyl ester (ISO-1), an inhibitor of macrophage migration inhibitory factor (MIF), on fetal kidney injury associated with the maternal acute necrotizing pancreatitis (ANP) and its potential mechanisms in a rat model. The APIP rat model was induced by retrograde infusion of sodium taurocholate saline solution into biliopancreatic duct. ISO-1 was given by intraperitoneally injection 30 min before the model was induced. The levels of maternal serum amylase, lipase, tumor necrosis factor-α (TNF-α) and interleukins (IL)-1β were measured. Maternal pancreas and fetal kidney injury were evaluated, and the expressions of MIF, phospho-p38MAPK (p-p38), nuclear factor-κB (NF-κB), TNF-α, IL-1β in fetal kidneys were detected. The results showed that fetal rats exhibited obvious acute kidney injury during APIP, and pregnant rats pretreated with ISO-1 notably attenuated the lesions. ISO-1 also significantly reduced the expression of MIF and the activations of p38MAPK, NF-κB, as well as the levels of TNF-α and IL-1β. These results indicated that ISO-1 could attenuate fetal kidney injury in pregnant rats with ANP by inhibiting MIF mediated p38MAPK/NF-κB signal pathways to reduce inflammatory response.

Molecular characterization of p38 MAPK from blunt snout bream (Megalobrama amblycephala) and its expression after ammonia stress, and lipopolysaccharide and bacterial challenge

p38 mitogen-activated protein kinase (MAPK) is an important protein which plays a key role in regulating the innate immunity, so exploring its molecular characterization is helpful in understanding the resistance against microbial infections in cultured fish. Here, a full-length cDNA of p38 MAPK was cloned from liver of blunt snout bream (Megalobrama amblycephala) which covered 2419 bp with an open reading frame of 1086 bp encoding 361 amino acids. p38 MAPK contained the characteristic structures of Thr-Gly-Tyr (TGY) motif and substrate binding site Ala-Thr-Arg-Trp (ATRW), which are conserved in MAPK family. To investigate p38 MAPK functions, two in vivo experiments were carried out to examine its expression following ammonia exposure and bacterial challenge. Also, an in vitro experiment was conducted to assess the role of p38 MAPK in inflammation of primary hepatocytes induced by lipopolysaccharide (LPS). The results showed the ubiquitous expression of p38 MAPK in all the tested tissues with varying levels. p38 MAPK mRNA expression was significantly up-regulated by ammonia stress and Aeromonas hydrophila challenge, and altered in a time-dependent manner. Moreover, the results indicated that the inflammatory response induced by LPS in hepatocytes is p38 MAPK dependent as knockdown of p38 MAPK using siRNA technology depressed the expression of IL-1β and IL-6. The findings in this study showed that p38 MAPK has anti-stress property, and plays key role in protection against bacterial infection and inflammation in blunt snout bream.

Mitogen-activated protein kinase kinase 6 is involved in the immune response to bacterial di-/tripeptide challenge in grass carp Ctenopharyngodon idella

Mitogen-activated protein kinase kinase 6 (MKK6) is an essential component of the p38MAPK signaling pathway, which is involved in the modulation of inflammation, cell apoptosis and survival responses in mammals. However, the function of MKK6s in teleosts is still unclear. In this study, a fish MKK6 homolog (CiMKK6) was first identified from the grass carp (Ctenopharyngodon idella), a freshwater fish. CiMKK6 cDNA encodes a putative protein of 357 amino acids that contains conserved structural characteristics of the MKK6 family, including the S_TKc domain, SVAKT motif and DVD site. The deduced CiMKK6 protein exhibits high sequence homology with other reported fish MKK6s and shares the closest relationship with MKK6 from Danio rerio. Quantitative real-time PCR (qRT-PCR) analysis revealed that CiMKK6 mRNA was widely expressed in all tested tissues and stages of embryonic development. Additionally, the transcript levels of CiMKK6 in the intestine were significantly upregulated in response to bacterial muramyl dipeptide (MDP) and L-Ala-γ-D-Glu-meso-diaminopimelic acid (Tri-DAP) stimulation. Moreover, subcellular localization analysis indicated that CiMKK6 was distributed in both the cytoplasm and the nucleus of HEK293T cells. Finally, overexpression of CiMKK6 significantly enhanced the transcriptional activity of the AP-1 reporter gene in HEK293T cells. Overall, these findings may help better clarify the immune function of teleost MKK6s and provide new insight into the immune defense mechanisms of grass carp.

Hypoxia potentiates monocyte-derived dendritic cells for release of tumor necrosis factor α via MAP3K8

Dendritic cells (DCs) constantly sample peripheral tissues for antigens, which are subsequently ingested to derive peptides for presentation to T cells in lymph nodes. To do so, DCs have to traverse many different tissues with varying oxygen tensions. Additionally, DCs are often exposed to low oxygen tensions in tumors, where vascularization is lacking, as well as in inflammatory foci, where oxygen is rapidly consumed by inflammatory cells during the respiratory burst. DCs respond to oxygen levels to tailor immune responses to such low-oxygen environments. In the present study, we identified a mechanism of hypoxia-mediated potentiation of release of tumor necrosis factor α (TNF-α), a pro-inflammatory cytokine with important roles in both anti-cancer immunity and autoimmune disease. We show in human monocyte-derived DCs (moDCs) that this potentiation is controlled exclusively via the p38/mitogen-activated protein kinase (MAPK) pathway. We identified MAPK kinase kinase 8 (MAP3K8) as a target gene of hypoxia-induced factor (HIF), a transcription factor controlled by oxygen tension, upstream of the p38/MAPK pathway. Hypoxia increased expression of MAP3K8 concomitant with the potentiation of TNF-α secretion. This potentiation was no longer observed upon siRNA silencing of MAP3K8 or with a small molecule inhibitor of this kinase, and this also decreased p38/MAPK phosphorylation. However, expression of DC maturation markers CD83, CD86, and HLA-DR were not changed by hypoxia. Since DCs play an important role in controlling T-cell activation and differentiation, our results provide novel insight in understanding T-cell responses in inflammation, cancer, autoimmune disease and other diseases where hypoxia is involved.

MAPK and PI3K signaling: At the crossroads of neural crest development

Receptor tyrosine kinase-mediated growth factor signaling is essential for proper formation and development of the neural crest. The many ligands and receptors implicated in these processes signal through relatively few downstream pathways, frequently converging on the MAPK and PI3K pathways. Despite decades of study, there is still considerable uncertainty about where and when these signaling pathways are required and how they elicit particular responses. This review summarizes our current understanding of growth factor-induced MAPK and PI3K signaling in the neural crest.

ERK/MAPK signaling and autism spectrum disorders

The MAPK pathway is a prominent intracellular signaling pathway regulating various intracellular functions. Components of this pathway are mutated in a related collection of congenital syndromes collectively referred to as neuro-cardio-facio-cutaneous syndromes (NCFC) or Rasopathies. Recently, it has been appreciated that these disorders are associated with autism spectrum disorders (ASD). In addition, idiopathic ASD has also implicated the MAPK signaling cascade as a common pathway that is affected by many of the genetic variants that have been found to be linked to ASDs. This chapter describes the components of the MAPK pathway and how it is regulated. Furthermore, this chapter will highlight the various functions of the MAPK pathway during both embryonic development of the central nervous system (CNS) and its roles in neuronal physiology and ultimately, behavior. Finally, we will summarize the perturbations to MAPK signaling in various models of autism spectrum disorders and Rasopathies to highlight how dysregulation of this pivotal pathway may contribute to the pathogenesis of autism.

β-1,3-glucan-lacking Aspergillus fumigatus mediates an efficient antifungal immune response by activating complement and dendritic cells

Complement system and dendritic cells (DCs) form - beside neutrophils and macrophages - the first line of defense to combat fungal infections. Therefore, we here studied interactions of these first immune elements with Aspergillus fumigatus lacking ß-1,3-glucans (fks1_tetOn^rep under repressed conditions) to mechanistically explain the mode of action of echinocandins in more detail. Echinocandins are cell wall active agents blocking β-glucan synthase, making the A. fumigatus fks1_tetOn mutant a good model to study immune-modulatory actions of these drugs. We now demonstrate herein, that complement was activated to significantly higher levels by the fks1-deficient strain compared to its respective wild type. This enhanced covalent linking of complement fragments to the A. fumigatus fks1_tetOn^rep mutant further resulted in enhanced DC binding and internalization of the fungus. Additionally, we found that fks1_tetOn^rep induced a Th1-/Th17-polarizing cytokine profile program in DCs. The effect was essentially dependent on massive galactomannan shedding, since blocking of DC-SIGN significantly reduced the fks1_tetOn^rep-mediated induction of an inflammatory cytokine profile.Our data demonstrate that lack of ß-1,3-glucan, also found under echinocandin therapy, results in improved recognition of Aspergillus fumigatus by complement and DCs and therefore not only directly affects the fungus by its fungistatic actions, but also is likely to exert indirect antifungal mechanisms by strengthening innate host immune mechanisms.Abbreviations: C: complement; CR:complement receptor; DC: dendritic cell; iDC: immature dendritic cell; DC-SIGN: Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin; ERK: extracellular signal-regulated kinases; JNK : c-Jun N-terminal kinases; MAPK: mitogen-activated protein kinase; NHS: normal human serum; PRR: pattern recognition receptor; Th :T helper; TLR :Toll-like receptor; WT: wild type.

Conjunctival Inflammatory Gene Expression Profiling in Dry Eye Disease: Correlations With HLA-DRA and HLA-DRB1

Purpose: In several multicenter clinical trials, HLA-DR was found to be a potential biomarker of dry eye disease (DED)'s severity and prognosis. Given the fact that HLA-DR receptor is a heterodimer consisting in an alpha and a beta chain, we intended to investigate the correlation of inflammatory targets with the corresponding transcripts, HLA-DRA and HLA-DRB1, to characterize specific targets closely related to HLA-DR expressed in conjunctival cells from patients suffering from DED of various etiologies.

Methods: A prospective study was conducted in 88 patients with different forms of DED. Ocular symptom scores, ocular-staining grades, tear breakup time (TBUT) and Schirmer test were evaluated. Superficial conjunctival cells were collected by impression cytology and total RNAs were extracted for analyses using the new NanoString^® nCounter technology based on an inflammatory human code set containing 249 inflammatory genes.

Results: Two hundred transcripts were reliably detected in conjunctival specimens at various levels ranging from 1 to 222,546 RNA copies. Overall, from the 88 samples, 21 target genes showed a highly significant correlation (R > 0.8) with HLA-DRA and HLA-DRB1, HLA-DRA and B1 presenting the highest correlation (R = 0.9). These selected targets belonged to eight family groups, namely interferon and interferon-stimulated genes, tumor necrosis factor superfamily and related factors, Toll-like receptors and related factors, complement system factors, chemokines/cytokines, the RIPK enzyme family, and transduction signals such as the STAT and MAPK families.

Conclusions: We have identified a profile of 21 transcripts correlated with HLA-DR expression, suggesting closely regulated signaling pathways and possible direct or indirect interactions between them. The NanoString^® nCounter technology in conjunctival imprints could constitute a reliable tool in the future for wider screening of inflammatory biomarkers in DED, usable in very small samples. Broader combinations of biomarkers associated with HLA-DR could be analyzed to develop new diagnostic approaches, identify tighter pathophysiological gene signatures and personalize DED therapies more efficiently.

Protective effect of Anwulignan against D-galactose-induced hepatic injury through activating p38 MAPK-Nrf2-HO-1 pathway in mice

Background

Liver aging is a significant risk factor for chronic liver diseases. Oxidative stress has been considered as a conjoint pathological mechanism for the initiation and progression of liver aging. It has been reported that d-galactose (d-gal)-induced hepatic injury is an experimental model well established closely similar to morphological and functional features of liver aging. Schisandra sphenanthera Rehd. et Wils (S. sphenanthera, Schisandraceae), as a famous tradi-tional Chinese medicine, has been used for thousands of years in China to treat various disorders, including liver dysfunctions. This study was aimed to understand whether Anwulignan, one of the monomeric compounds in the lignans from S. sphenanthera, could improve the hepatic injury induced by d-gal in mice and to examine the possible mechanisms.

Methods

ICR mice were used to produce hepatic injury by 220 mg kg-1 d-gal subcutaneously once daily for 42 days. The effects of oral Anwulignan on liver index; serial AST and ALT levels; histological changes; SOD, GSH-Px, MDA, and 8-OHdG in the liver and peripheral blood; expression of p38 mitogen-activated protein kinase (MAPK), Nrf2, and HO-1 in the liver; and HepG2 cell viability, and decrease caspase-3 contents in liver were examined.

Results

Anwulignan could significantly increase the liver index, lower aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in the peripheral blood, elevate superoxide dis-mutase (SOD) and glutathione peroxidase (GSH-Px) activities, and decrease malonaldehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG) contents in the peripheral blood and liver. Furthermore, Anwulignan could upregulate the expression of p38 mitogen-activated protein kinase (MAPK), Nrf2, and HO-1 in the liver, increase the HepG2 cell viability, and decrease caspase-3 contents in liver.

Conclusion

Anwulignan has protective effects against the hepatic injury induced by d-gal, which may be related to its antioxidant capacity through activating p38 MAPK-Nrf2-HO-1 pathway, increases the injured cell viability, and decreases the caspase-3 contents in liver.

Dual-specificity MAP kinase phosphatases in health and disease

It is well established that a family of dual-specificity MAP kinase phosphatases (MKPs) play key roles in the regulated dephosphorylation and inactivation of MAP kinase isoforms in mammalian cells and tissues. MKPs provide a mechanism of spatiotemporal feedback control of these key signalling pathways, but can also mediate crosstalk between distinct MAP kinase cascades and facilitate interactions between MAP kinase pathways and other key signalling modules. As our knowledge of the regulation, substrate specificity and catalytic mechanisms of MKPs has matured, more recent work using genetic models has revealed key physiological functions for MKPs and also uncovered potentially important roles in regulating the pathophysiological outcome of signalling with relevance to human diseases. These include cancer, diabetes, inflammatory and neurodegenerative disorders. It is hoped that this understanding will reveal novel therapeutic targets and biomarkers for disease, thus contributing to more effective diagnosis and treatment for these debilitating and often fatal conditions.

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A comprehensive review of the dual-specificity MAP kinase Phosphatases (MKPs)

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Focus is on MKPs in the regulation of MAPK signalling in health and disease.

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Covers roles of MKPs in inflammation, obesity/diabetes, cancer and neurodegeneration

SUMOs Mediate the Nuclear Transfer of p38 and p-p38 during Helicobacter Pylori Infection

The p38 mitogen activated protein kinase (MAPK) signaling pathway has been suggested to play a significant role in the gastric mucosal inflammatory response to chronic Helicobacter pylori (H. pylori) infection. Nuclear translocation is thought to be important for p38 function, but no nuclear translocation signals have been found in the protein and no nuclear carrier proteins have been identified for p38. We have investigated the role of small ubiquitin-related modifier (SUMO) in the nuclear transfer of p38 in response to H. pylori infection. Exposure of human AGS cells to H. pylori induced the activation of p38 and the expression of SUMOs, especially SUMO-2. SUMO knockdown counteracted the effect of H. pylori infection by decreasing the resulting p38 mediated cellular apoptosis through a reduction in the nuclear fraction of phosphorylated p38. We identified a non-covalent interaction between SUMOs and p38 via SUMO interaction motifs (SIMs), and showed that SUMO-dependent nuclear transfer of p38 was decreased upon mutation of its SIMs. This study has identified a new pathway of p38 nuclear translocation, in response to H. pylori infection. We conclude that in the presence of H. pylori SUMO-2 has a major role in regulating nuclear levels of p38, through non-covalent SUMO-p38 interactions, independent of the p38 phosphorylation state.

Polyhexamethylene guanidine phosphate induces IL-6 and TNF-α expression through JNK-dependent pathway in human lung epithelial cells

Polyhexamethylene guanidine phosphate (PHMG) is an antimicrobial biocide that causes severe lung injury accompanied with inflammation and subsequent fibrosis. Cytokines mediate the inflammatory response, leading to fibrosis in injured tissues. PHMG is known to induce the expression of various cytokines in vitro and in vivo. In the present study, we investigated the involvement of three MAPK subfamilies (JNK, p38 MAPK, and ERK) in PHMG-induced cytokine expression in A549 human lung epithelial cells. Our in vivo and in vitro data indicated that PHMG induced an increase in mRNA expression of IL-6 and TNF-α, and enhanced the phosphorylation of JNK, p38 MAPK, and ERK. Further, we investigated the involvement of MAPKs in PHMG-induced mRNA expression of IL-6 and TNF-α using JNK, p38 MAPK, and ERK inhibitors in A549 cells. Pre-treatment with the JNK inhibitor but not the p38 MAPK or ERK inhibitor, significantly attenuated the PHMG-induced mRNA expression of IL-6 and TNF-α. These results suggest that the activation of JNK is involved at least partially in the induction of IL-6 or TNF-α expression by PHMG in A549 cells.

2-arachidonyl glycerol modulates astrocytic glutamine synthetase via p38 and ERK1/2 pathways

Background

The glutamine synthetase (GS), an astrocyte-specific enzyme, is involved in lipopolysaccharide (LPS)-induced inflammation which activates the mitogen-activated protein kinase (MAPK) signaling. Endocannabinoid 2-arachidonyl glycerol (2-AG) has been described to serve as an endogenous mediator of analgesia and neuroprotection. However, whether 2-AG can directly influence astrocytic GS and MAPK expressions remains unknown.

Methods

In the present study, the effects of 2-AG on astrocytic GS expression, p38 and ERK1/2 expression, cell viability, and apoptosis following LPS exposure were investigated.

Results

The results revealed that LPS exposure increased GS expression with p38 activation in the early phase and decreased GS expression with activation of ERK1/2, decrease of cell viability, and increase of apoptosis in the late phase. Inhibition of p38 reversed GS increase in the early phase while inhibition of ERK1/2 reversed GS decrease in the late phase induced by LPS exposure. 2-AG protected astrocytes from increase of apoptosis and decrease of cell viability induced by the late phase of LPS exposure. In the early phase of LPS exposure, 2-AG could suppress the increase of GS expression and activation of p38 signaling. In the late phase of LPS exposure, 2-AG could reverse the decrease of GS expression and activation of ERK1/2 induced by LPS.

Conclusion

These findings suggest that 2-AG could maintain the GS expression in astrocytes to a relatively stable level through modulating MAPK signaling and protect astrocytes from LPS exposure.

Immunomodulatory effects of phytogenics in chickens and pigs - A review

Environmental stressors like pathogens and toxins may depress the animal immune system through invasion of the gastrointestinal tract (GIT) tract, where they may impair performance and production, as well as lead to increased mortality rates. Therefore, protection of the GIT tract and improving animal health are top priorities in animal production. Being natural-sourced materials, phytochemicals are potential feed additives possessing multiple functions, including: anti-inflammatory, anti-fungal, anti-viral and antioxidative properties. This paper focuses on immunity-related physiological parameters regulated by phytochemicals, such as carvacrol, cinnamaldehyde, curcumin, and thymol; many studies have proven that these phytochemicals can improve animal performance and production. On the molecular level, the impact of inflammatory gene expression on underlying mechanisms was also examined, as were the effects of environmental stimuli and phytochemicals in initiating nuclear factor kappa B and mitogen-activated protein kinases signaling pathways and improving health conditions.

Amifostine Analog, DRDE-30, Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice

Bleomycin (BLM) is an effective curative option in the management of several malignancies including pleural effusions; but pulmonary toxicity, comprising of pneumonitis and fibrosis, poses challenge in its use as a front-line chemotherapeutic. Although Amifostine has been found to protect lungs from the toxic effects of radiation and BLM, its application is limited due to associated toxicity and unfavorable route of administration. Therefore, there is a need for selective, potent, and safe anti-fibrotic drugs. The current study was undertaken to assess the protective effects of DRDE-30, an analog of Amifostine, on BLM-induced lung injury in C57BL/6 mice. Whole body micro- computed tomography (CT) was used to non-invasively observe tissue damage, while broncheo-alveolar lavage fluid (BALF) and lung tissues were assessed for oxidative damage, inflammation and fibrosis. Changes in the lung density revealed by micro-CT suggested protection against BLM-induced lung injury by DRDE-30, which correlated well with changes in lung morphology and histopathology. DRDE-30 significantly blunted BLM-induced oxidative stress, inflammation and fibrosis in the lungs evidenced by reduced oxidative damage, endothelial barrier dysfunction, Myeloperoxidase (MPO) activity, pro-inflammatory cytokine release and protection of tissue architecture, that could be linked to enhanced anti-oxidant defense system and suppression of redox-sensitive pro-inflammatory signaling cascades. DRDE-30 decreased the BLM-induced augmentation in BALF TGF-β and lung hydroxyproline levels, as well as reduced the expression of the mesenchymal marker α-smooth muscle actin (α-SMA), suggesting the suppression of epithelial to mesenchymal transition (EMT) as one of its anti-fibrotic effects. The results demonstrate that the Amifostine analog, DRDE-30, ameliorates the oxidative injury and lung fibrosis induced by BLM and strengthen its potential use as an adjuvant in alleviating the side effects of BLM.

YY1 Upregulates Checkpoint Receptors and Downregulates Type I Cytokines in Exhausted, Chronically Stimulated Human T Cells

T cells infiltrate affected organs in chronic infections and malignancy, but they may fail to eradicate virus-infected cells or tumor because of exhaustion. This report describes a Yin Yang-1 (YY1)-centered mechanism for diverse components that have been correlated with exhaustion. Utilizing an in vitro reconstruction of chronic T cell activation, YY1 is shown to positively regulate the checkpoint receptors PD1, Lag3, and Tim3 and to negatively regulate the type I cytokines interleukin-2 (IL-2) (in collaboration with Ezh2 histone methyltransferase) and interferon gamma (IFN-?). Other tests suggest that IL-2 failure drives a large component of cytotoxic functional decline rather than solely checkpoint receptor-ligand interactions that have been the focus of current anti-exhaustion therapies. Clinical evaluations confirm elevated YY1 and Ezh2 in melanoma tumor-infiltrating lymphocytes and in PD1+ T cells in patients with HIV. Exhaustion is revealed to be an active process as the culmination of repetitive two-signal stimulation in a feedback loop via CD3/CD28?p38MAPK/JNK?YY1? exhaustion.

Characterization and expression patterns of ERK1 and ERK2 from Epinephelus coioides against Cryptocaryon irritans infection

Mitogen-activated protein kinases (MAPKs), a group of serine-threonine protein kinases, play a crucial role in immunoreaction response to extra environmental stresses. In this study, two novel MAPKs, Ec-ERK1 and Ec-ERK2, were identified from Epinephelus coioides. Both Ec-ERK1 and Ec-ERK2 sequences contain a highly conserved Thr-Glu-Tyr (TEY) motif, an HRD domain, and an ATP binding loop containing GXGXXG. An analysis of phylogenetic relationships demonstrated that ERK amino acid sequences were conserved between different species indicating that the functions may be similar. Ec-ERK1 and Ec-ERK2 mRNA can be detected in all thirteen tissues examined, but the expression level is different in these tissues. The expression patterns of these two genes in E. coioides were also detected against Cryptocaryon irritans infection, which is capable of killing large numbers of fish in a short time and has a serious impact on aquaculture. The expression was up-regulated in most of the tissues examined, with the highest expressions of Ec-ERK1 (3.9 times) occurring in the head kidney and Ec-ERK2 (3.5 times) occurring in the spleen. There was no significant correlation between the expression of Ec-ERK1/Ec-ERK2 and the expression of nuclear factor kappaB (NF-kB). The results indicated the sequences and the characters of Ec-ERK1/ERK2 were conserved, Ec-ERK1/ERK2 showed tissue-specific expression patterns in healthy grouper, and their expressions were significantly varied post C. irritans infection, suggesting Ec-ERK1/ERK2 may play important roles in these tissues during pathogen-caused inflammation.

Effect of the Arctic terrestrial plant Ranunculus hyperboreus on LPS-induced inflammatory response via MAPK pathways

The Arctic flora hosts a limited number of species due to its extreme environmental conditions which also yield novel and unique secondary metabolites from withstanding plants. Considering a lack of research on bioactivity potential of Arctic flora, Ranunculus hyperboreus, an Arctic plant, was studied for its anti-inflammatory potential as a part of ongoing research on discovering novel natural bioactive products. Solvent-based fractions (H2O, n-BuOH, 85% aq. MeOH, n-hexane) from R. hyperboreus extract were observed to decrease the elevated nitrate amount during the inflammatory response of lipopolysaccharide-induced mouse macrophage RAW264.7 cells. To some extent, treatment with fractions was able to regulate the expression and protein levels of inflammation-related enzymes, iNOS and COX-2, and pro-inflammatory cytokines, TNF-α, IL-1β, and IL-6. The most active fractions, H2O and 85% aq. MeOH, were suggested to exert their effect through suppressed activation of MAPK pathways, especially JNK. Based on the studies of same species, phenolic glycosides were suggested to be the main active ingredients. To our knowledge, this is the first report of any bioactivity of R. hyperboreus which could be a valuable source of natural bioactive agents against inflammation.

Structure-based design, synthesis, and biological evaluation of imidazo[1,2-b]pyridazine-based p38 MAP kinase inhibitors

We identified novel potent inhibitors of p38 MAP kinase using structure-based design strategy. X-ray crystallography showed that when p38 MAP kinase is complexed with TAK-715 (1) in a co-crystal structure, Phe169 adopts two conformations, where one interacts with 1 and the other shows no interaction with 1. Our structure-based design strategy shows that these two conformations converge into one via enhanced protein-ligand hydrophobic interactions. According to the strategy, we focused on scaffold transformation to identify imidazo[1,2-b]pyridazine derivatives as potent inhibitors of p38 MAP kinase. Among the herein described and evaluated compounds, N-oxide 16 exhibited potent inhibition of p38 MAP kinase and LPS-induced TNF-α production in human monocytic THP-1 cells, and significant in vivo efficacy in rat collagen-induced arthritis models. In this article, we report the discovery of potent, selective and orally bioavailable imidazo[1,2-b]pyridazine-based p38 MAP kinase inhibitors with pyridine N-oxide group.

Thyroid stimulating hormone stimulates the expression of glucose transporter 2 via its receptor in pancreatic β cell line, INS-1 cells

Thyroid stimulating hormone (TSH) stimulates the secretion of thyroid hormones by binding the TSH receptor (TSHR). TSHR is well-known to be expressed in thyroid tissue, excepting it, TSHR has also been expressed in many other tissues. In this study, we have examined the expression of TSHR in rat pancreatic islets and evaluated the role of TSH in regulating pancreas-specific gene expression. TSHR was confirmed to be expressed in rodent pancreatic islets and its cell line, INS-1 cells. TSH directly affected the glucose uptake in INS cells by up-regulating the expression of GLUT2, and furthermore this process was blocked by SB203580, the specific inhibitor of the p38 MAPK signaling pathway. Similarly, TSH stimulated GLUT2 promoter activity, while both a dominant-negative p38MAPK α isoform (p38MAPK α-DN) and the specific inhibitor for p38MAPK α abolished the stimulatory effect of TSH on GLUT2 promoter activity. Finally, INS-1 cells treated with TSH showed increased protein level of glucokinase and enhanced glucose-stimulated insulin secretion. Together, these results confirm that TSHR is expressed in INS-1 cells and rat pancreatic islets, and suggest that activation of the p38MAPK α might be required for TSH-induced GLUT2 gene transcription in pancreatic β cells.

Novel proteasome inhibitor delanzomib sensitizes cervical cancer cells to doxorubicin-induced apoptosis via stabilizing tumor suppressor proteins in the p53 pathway

Cervical cancer, the third most commonly occurring cancer, is the second leading cause of cancer related mortality among women. Aberrant ubiquitination and proteasome activity, both human papillomavirus and tumor derived, have been shown to contribute to tumor angiogenesis, proliferation, and invasion in many cancers, including cervical cancer. Thus, small molecule proteasome inhibitors are a potential and strategic treatment option for cervical cancer. In this study, novel proteasome inhibitor delanzomib (CEP-18770) exhibited potent pro-apoptotic and cytotoxic effects on a panel of cervical cancer cell lines by blocking proteasomal activity. Delanzomib also significantly sensitized cervical cancer cells to treatment of doxorubicin (Dox), a traditional chemotherapeutic agent. Furthermore, proteasome inhibition revealed stabilization of p53 and p53 transcriptional targets and induction of p38/JNK phosphorylation. Additionally, delanzomib worked synergistically with Dox to further upregulate p53 and its downstream targets and enhanced Dox-induced p38 phosphorylation. Our study strongly supports the 26S proteasome as a potential therapeutic target in cervical cancer and proteasome inhibition by delanzomib may be a potential treatment strategy for cervical cancer patients.

Transcriptional and Post-Translational Targeting of Myocyte Stress Protein 1 (MS1) by the JNK Pathway in Cardiac Myocytes

Myocyte Stress Protein 1 (MS1) is a muscle-specific, stress-responsive, regulator of gene expression. It was originally identified in embryonic mouse heart which showed increased expression in a rat model of left ventricular hypertrophy. To determine if MS1 was responsive to other stresses relevant to cardiac myocyte function, we tested if it could be induced by the metabolic stresses associated with ischaemia/reperfusion injury in cardiac myocytes. We found that metabolic stress increased MS1 expression, both at the mRNA and protein level, concurrent with activation of the c-Jun N-terminal Kinase (JNK) signalling pathway. MS1 induction by metabolic stress was blocked by both the transcription inhibitor actinomycin D and a JNK inhibitor, suggesting that activation of the JNK pathway during metabolic stress in cardiac myocytes leads to transcriptional induction of MS1. MS1 was also found to be an efficient JNK substrate in vitro, with a major JNK phosphorylation site identified at Thr-62. In addition, MS1 was found to co-precipitate with JNK, and inspection of the amino acid sequence upstream of the phosphorylation site, at Thr-62, revealed a putative Mitogen-Activated Protein Kinase (MAPK) binding site. Taken together, these data identify MS1 as a likely transcriptional and post-translational target for the JNK pathway in cardiac myocytes subjected to metabolic stress.