Regulation Of Mitogen-activated Protein Kinase Research Articles

Negative Feedback Regulation of MAPK Signaling Is an Important Driver of CLL Progression

Chronic lymphocytic leukemia (CLL) represents approximately 25% of all new cases of leukemia in the USA. Insight into the pathogenesis of CLL has led to the development of highly effective treatments in the past decade. Nevertheless, CLL patients with activating mutations in the mitogen-activated protein kinase (MAPK) pathway, which enables cell proliferation and differentiation, comprise a distinct subgroup with poor clinical prognosis such as shorter treatment-free survival and higher drug resistance. Dual specificity protein phosphatases (DUSPs) negatively regulate MAPK signaling and are required to limit and terminate the activating signal. Whether DUSP signaling is crucial for the development and progression of MAPK driven CLL is unknown. Thus, in this study we investigated the expression and functional relevance of negative MAPK regulators DUSP1 and DUSP6 in CLL. Analyzing mRNA data sets of CLL patients, we discovered that DUSP1 and DUSP6 were broadly expressed in CLL. High expression levels of DUSP6, though not DUSP1, were found in cases with activating mutations within the MAPK pathway and correlated with a poor clinical outcome, indicated by shorter time-to-treatment and overall survival. To investigate the functional relevance of DUSP1- and DUSP6-mediated negative MAPK regulation in CLL, we tested the effects of the dual-specific DUSP1/6 inhibitor BCI on CLL cells. DUSP1/6 inhibition in vitro resulted in a dose-dependent induction of specific cell death of CLL cells, whereas B cells from healthy donors remained unaffected. Treatment of mice with an adoptively transferred murine CLL with an in vivo applicable derivate of BCI also significantly decreased CLL levels in the spleen and peritoneal cavity, compared to a vehicle treated control group. Further, CRISPR/Cas9-mediated knockout of DUSP1 or DUSP6 in the CLL cell line MEC-1 reduced cell proliferation and fitness; however, DUSP1/6 double knockouts lead to syngeneic lethality. Thus, DUSP1 and DUSP6 are crucial for negative MAPK pathway regulation to enable cell survival. To assess changes in intracellular signaling pathways after DUSP1/6 inhibition, we performed a phospho-proteome analysis of BCI treated patient-derived CLL cells and compared them to vehicle treated cells. As expected, a significant deregulation of B-cell receptor and MAPK signaling was detected after inhibition, with an increase in the activating phosphorylation on ERK1 and ERK2, which are targeted by DUSP1/6, confirming on-target specificity of BCI using an unbiased approach. To gain insight into the mechanism driving cell death, we conducted a BCI time course analysis followed by a phospho-proteome screen and observed that the DNA damage response (DDR) and the apoptosis pathway were among the strongest regulated pathways upon DUSP1/6 inhibition in MEC-1 cells. To validate these findings, we used immunoblotting and detected phosphorylation of DDR key molecules, such as ATF2 and c-JUN, in human CLL samples after DUSP1/6 inhibition. We also used flow cytometry to confirm acute activation of the MAPK pathway after BCI treatment by detecting increased phospho-γH2AX (DNA damage) and phosphatidylserine (apoptosis) levels. Furthermore, we showed that the apoptotic cell death is promoted by CHK1/2 kinases and depends on MAPK activity. Chemotherapeutic drug resistances are often detected in patients with deletion of p53 or ATM, central regulators of the DDR. Hence, we tested the effectiveness of DUSP1/6 inhibition on patient derived CLLs carrying a loss of function variation of p53 or ATM. We did not detect a significant difference in cytotoxicity, indicating DUSP1/6 inhibition effectively decreases CLL viability, even in cases without functional p53/ATM-mediated DDR. Finally, we generated a MEC-1 cell line resistant to the chemotherapeutic agent idelalisib, as a model for drug resistant CLLs. As the sensitivity to idelalisib decreased, the cells became more sensitive to BCI. When comparing the effects of BCI on CLL cells from treatment naïve patients compared to ibrutinib-refractory patients, we found no differences in sensitivity to DUSP1/6 inhibition. In conclusion, we show that MAPK deregulation by DUSP1/6 inhibition is highly effective to induce cytotoxic cell death in CLL cells, even without functional p53/ATM-mediated DDR; hence, we suggest DUSP1/6 inhibition is a promising approach to treat drug resistant and refractory CLLs. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Reduning Attenuates LPS-Induced Human Unmilical Vein Endothelial Cells (HUVECs) Apoptosis Through PI3K-AKT Signaling Pathway.

The molecular mechanism of Reduning (RDN) in the treatment of sepsis was analyzed based on network pharmacology. The system pharmacology method was administered to search the active ingredients and targets of RDN, identify the sepsis-related genes, and determine the targets of RDN in the treatment of sepsis. Cytoscape was used to build a “drug component-target” network to screen key compounds. A protein-protein interaction (PPI) network was constructed using STRING, and core targets were revealed through topological analysis. 404 shared targets of RDN and sepsis were introduced into DAVID Bioinformatics Resources 6.8 for GO and KEGG enrichment analysis to predict their possible signaling pathways and explore their molecular mechanisms. GO enrichment analysis highlighted that they were largely related to protein phosphorylation, inflammatory reaction, and positive regulation of mitogen-activated protein kinase (MAPK) cascade. KEGG enrichment analysis outlined that they were enriched in PI3K-AKT signaling pathway, calcium signaling pathway, rhoptry-associated protein 1 (Rap1) signaling pathway, and advanced glycation end products and receptors for advanced glycation end products (AGE-RAGE) signaling pathway. Molecular biological validation results exposed that RDN could significantly improve the protein expression of p-AKT and p-PI3K, alleviate apoptosis-related proteins expression level and decrease apoptosis rate in LPS-induced HUVECs. In conclusion, it was illustrated that RDN could considerably constrain LPS-induced apoptosis by activating the PI3K-AKT signaling pathway, which advocated a basis for fundamental mechanism research and clinical application of RDN in the treatment of sepsis.

Systemic lupus erythematosus dysregulates the expression of long noncoding RNAs in placentas

BackgroundSystemic lupus erythematosus (SLE) can cause placental dysfunctions, which may result in pregnancy complications. Long noncoding RNAs (lncRNAs) are actively involved in the regulation of immune responses during pregnancy. The present study aimed to determine the lncRNA expression profiles in placentas from women with SLE to gain new insights into the underlying molecular mechanisms in SLE pregnancies.MethodsRNA sequencing (RNA-seq) analysis was performed to identify SLE-dysregulated lncRNAs and mRNAs in placentas from women with SLE and normal full-term (NT) pregnancies. Bioinformatics analysis was conducted to predict the biological functions of these SLE-dysregulated lncRNAs and mRNAs.ResultsRNA-seq analysis identified 52 dysregulated lncRNAs in SLE placentas, including 37 that were upregulated and 15 downregulated. Additional 130 SLE-dysregulated mRNAs were discovered, including 122 upregulated and 8 downregulated. Bioinformatics analysis revealed that SLE-dysregulated genes were associated with biological functions and gene networks, such as regulation of type I interferon-mediated signaling pathway, response to hypoxia, regulation of MAPK (mitogen-activated protein kinase) cascade, response to steroid hormone, complement and coagulation cascades, and Th1 and Th2 cell differentiation.ConclusionsThis is the first report of the lncRNA profiles in placentas from SLE pregnancies. These results suggest that the aberrant expression and the potential regulatory function of lncRNAs in placentas may play comprehensive roles in the pathogenesis of SLE pregnancies. SLE-dysregulated lncRNAs may potentially serve as biomarkers for SLE.

Cingulin b Is Required for Zebrafish Lateral Line Development Through Regulation of Mitogen-Activated Protein Kinase and Cellular Senescence Signaling Pathways.

Cingulin, a cytoplasmic element of tight junctions (TJs), is involved in maintenance of the integrity of epithelial and endothelial cells. However, the role of cingulin in the development of auditory organs remains unclear. Zebrafish is popular as a model organism for hearing research. Using the whole mount in situ hybridization (WISH) experiment, we detected the expression of cingulin b in the posterior lateral line system (PLLs) of zebrafish. We traced the early development progress of zebrafish PLLs from 36 hpf to 72 hpf, and found that inhibition of cingulin b by target morpholinos resulted in severe developmental obstruction, including decreased number of neuromasts, reduced proliferative cells in the primordium, and repressed hair cell differentiation in the neuromasts. To examine the potential mechanism of cingulin b in the development of zebrafish PLL neuromasts, we performed RNA-seq analysis to compare the differently expressed genes (DEGs) between cingulin b knockdown samples and the controls. The KEGG enrichment analysis revealed that MAPK signaling pathway and cellular senescence were the key pathways with most DEGs in cingulin b-MO morphants compared to the Control-MO embryos. Furthermore, quantitative RT-PCR analysis confirmed the findings by RNA-seq that the transcript levels of cell cycle negative regulators such as tp53 and cdkn1a, were remarkably upregulated after inhibition of cingulin b. Our results therefore indicated an important role of cingulin b in the development of auditory organs, and MAPK signaling pathway was inhibited while cellular senescence pathway was activated after downregulation of cingulin b. We bring forward new insights of cingulin by exploring its function in auditory system.

Cynarin attenuates LPS-induced endothelial inflammation via upregulation of the negative regulator MKP-3

ABSTRACT Clinical observations have revealed that non-resolving low-grade inflammation is linked to the pathogenesis of chronic inflammatory diseases, for example arthritis, atherosclerosis, Alzheimer’s disease, diabetes, and chronic kidney disease. Interestingly, low levels of circulating lipopolysaccharides (LPS) derived from the outer membrane of gram-negative bacteria appear to be one of the primary causes of persistent low-grade inflammation. The inner surface of the blood vessels is lined with endothelial cells; therefore, even low levels of circulating LPS can directly activate these cells and elicit specific cellular responses, such as an increase in the expression levels of cell adhesion molecules and proinflammatory mediators. In endothelial cells, LPS exposure results in an inflammatory response through activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases. Cynarin, a phytochemical found in artichokes, has several pharmacological properties against endothelial inflammation. In the present study, we discovered that cynarin suppressed the LPS-induced increase in the expression levels of vascular cell adhesion molecule-1 and proinflammatory mediators such as monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α), and interleukin-1β in EA.hy926 cells. Further, cynarin inhibited the activation of p38 and NF-κB pathways by inducing the negative regulator mitogen-activated protein kinase phosphatase 3 (MKP-3) in LPS-stimulated EA.hy926 cells. In conclusion, cynarin alleviates inflammation by upregulating MKP-3, a negative regulator of p38 and NF-κB, and it may be a therapeutic option for treating endothelial inflammation-related diseases.

Human Papillomavirus Type 16 Early Protein E7 Activates Autophagy through Inhibition of Dual-Specificity Phosphatase 5.

Consistent high-risk human papillomavirus (HPV) infection leads to various malignant cancers. Autophagy can promote cancer progression by helping cancer cells survive under stress or induce oncogenic effects when mutations or abnormalities occur. Mitogen activated protein kinases (MAPKs) can transduce various external or intrinsic stimuli into cellular responses, including autophagy, and dual-specificity phosphates (DUSPs) contribute to the direct regulation of MAPK activities. Previously, we showed that expression of DUSP5 was repressed in HPV16 E7-expressing normal human epidermal keratinocytes (NHEKs). Here we show that clinical HPV16 E7-positive precancerous and cancerous tissues also demonstrate low DUSP5 levels compared with control tissues, indicating that the inverse correlation between HPV16 E7 and DUSP5 is clinically relevant. We furthermore investigated the autophagy response in both DUSP5-deficient and HPV16 E7-expressing NHEKs. Confocal microscopy and Western analysis showed induction of LC3-II levels, autophagosome formation and autophagy fluxes in DUSP5-deficient NHEKs. Furthermore, Western analysis demonstrated specific induction of phosphorylated ERK in DUSP5-deficient and HPV16 E7-expressing NHEKs, indicating that HPV16 E7-mediated repression of DUSP5 results in induced MAPK/ERK signaling. Finally, phosphorylated mTOR and ULK (S757) were reduced in DUSP5-deficient NHEKs, while phosphorylated ULK (S555) and AMPK were increased, thereby inducing canonical autophagy through the mTOR and AMPK pathways. In conclusion, our results demonstrate that HPV16 E7 expression reduces DUSP5 levels, which in turn results in active MAPK/ERK signaling and induction of canonical autophagy through mTOR and MAPK regulation. Given its demonstrated inverse correlation with clinical cancerous tissues, DUSP5 may serve as a potential therapeutic target for cervical cancer.

A new cell death program regulated by toll-like receptor 9 through p38 mitogen-activated protein kinase signaling pathway in a neonatal rat model with sepsis associated encephalopathy.

Background:Sepsis, a serious condition with high mortality, usually causes sepsis associated encephalopathy (SAE) that involves neuronal cell death. However, the cell death programs involved and their underlying mechanisms are not clear. This study aimed to explore the regulatory mechanisms of different cell death programs in SAE.Methods:A neonatal rat model of SAE was established by cecal ligation and perforation. Survival rate and vital signs (mean arterial pressure and heart rate) were monitored, nerve reflexes were evaluated, and cortical pathological changes were observed by hematoxylin and eosin staining. The expression of pyroptosis, apoptosis, and necroptosis (PANoptosis)-related proteins, mitogen- activated protein kinase (MAPK), and its upstream regulator toll-like receptor 9 (TLR9) were detected. The expression of TLR9 in neurons was observed by immunofluorescence staining. The ultrastructure of neurons was observed by transmission electron microscope.Results:First, PANoptosis was found in cortical nerve cells of the SAE rats. Meanwhile, the subunits of MAPKs, p38 MAPK, Jun N- terminal kinase, and extracellular signal-regulated kinase (ERK) were activated. After pharmacologically inhibiting each of the subunits, only p38 MAPK was found to be associated with PANoptosis. Furthermore, blocking the p38 MAPK signaling pathway activated necroptosis but inhibited apoptosis and pyroptosis. When necroptosis was pharmacologically inhibited, apoptosis and pyroptosis were reactivated. Finally, we found that the expression of TLR9, a regulator of MAPKs, was significantly increased in this model. After down-regulation of TLR9, p38 MAPK, and ERK signaling pathways were inhibited, which led to the inhibition of PANoptosis. Further analysis found that down-regulation of TLR9 improved the survival rate and reduced the pathological changes in SAE rats.Conclusions:Our study showed that the programs comprising PANoptosis are activated simultaneously in SAE rats. TLR9 activated PANoptosis through the p38 MAPK signaling pathway. TLR9 may work as a potential target for SAE treatment.

S-Nitrosation of Arabidopsis thaliana Protein Tyrosine Phosphatase 1 Prevents Its Irreversible Oxidation by Hydrogen Peroxide.

Tyrosine-specific protein tyrosine phosphatases (Tyr-specific PTPases) are key signaling enzymes catalyzing the removal of the phosphate group from phosphorylated tyrosine residues on target proteins. This post-translational modification notably allows the regulation of mitogen-activated protein kinase (MAPK) cascades during defense reactions. Arabidopsis thaliana protein tyrosine phosphatase 1 (AtPTP1), the only Tyr-specific PTPase present in this plant, acts as a repressor of H2O2 production and regulates the activity of MPK3/MPK6 MAPKs by direct dephosphorylation. Here, we report that recombinant histidine (His)-AtPTP1 protein activity is directly inhibited by H2O2 and nitric oxide (NO) exogenous treatments. The effects of NO are exerted by S-nitrosation, i.e., the formation of a covalent bond between NO and a reduced cysteine residue. This post-translational modification targets the catalytic cysteine C265 and could protect the AtPTP1 protein from its irreversible oxidation by H2O2. This mechanism of protection could be a conserved mechanism in plant PTPases.

Guilingji Protects Against Spermatogenesis Dysfunction From Oxidative Stress via Regulation of MAPK and Apoptotic Signaling Pathways in Immp2l Mutant Mice.

Male infertility is a major health issue with an estimated prevalence of 4.2% of male infertility worldwide. Oxidative stress (OS) is one of the main causes of male infertility, which is characterized by excessive reactive oxygen species (ROS) or lack of antioxidants. Meanwhile, it is reported that oxidative stress plays an important role in the spermatogenic impairment in Inner mitochondrial membrane peptidase 2-like (Immp2l) mutant mice. In this study, we focused on the potential mechanism of Guilingji in protecting the spermatogenic functions in Immp2l mutant mice. The results revealed that Immp2l mutant mice exhibit impaired spermatogenesis and histology shows seminiferous tubules with reduced spermatogenic cells. After administration of Guilingji [150 mg/kg per day intragastric gavage], however, alleviated spermatogenesis impairment and reversed testis histopathological damage and reduced apoptosis. What’s more, western blotting and the levels of redox classic markers revealed that Guilingji can markedly reduce reactive oxygen species. Moreover, Guilingji treatment led to inhibition of the phosphorylation of mitogen-activated protein kinase (MAPK), regulated apoptosis in the cells. In summary, Guilingji can improve spermatogenesis in Immp2l mutant mice by regulating oxidation-antioxidant balance and MAPK pathway. Our data suggests that Guilingji may be a promising and effective antioxidant candidate for the treatment of male infertility.

Ligstroside aglycon, an extra virgin olive oil secoiridoid, prevents inflammation by regulation of MAPKs, JAK/STAT, NF-κB, Nrf2/HO-1, and NLRP3 inflammasome signaling pathways in LPS-stimulated murine peritoneal macrophages.

Ligstroside aglycon (LA) is one of the main polyphenols in extra virgin olive oil (EVOO); nevertheless, it is scarcely investigated. The aim of this study was to evaluate the immunomodulatory and anti-inflammatory effects of LA on lipopolysaccharide (LPS)-stimulated murine peritoneal macrophages, as well as the potential signaling pathways involved. Isolated macrophages were treated with LA (50, 25, and 12.5 μM) in the presence or absence of LPS (5 μg ml-1) for 18 h. Cell viability was determined using the sulforhodamine B (SRB) assay. Nitric oxide (NO) and pro-inflammatory cytokine production was analyzed by the Griess method and enzyme-linked immunosorbent assay (ELISA), respectively. Protein expression of pro-inflammatory markers and signaling pathways were evaluated by western blot analysis. LA showed significant antioxidant and anti-inflammatory effects through decreasing oxidative stress markers such as NO production, inducible nitric oxide synthase (iNOS) and NADPH oxidase-1 (NOX-1) protein expression. Besides, LA was able to reduce pro-inflammatory cytokine levels and modulate cyclo-oxygenase-2 (COX-2), and microsomal prostaglandin E synthase-1 (mPGEs-1) protein overexpression. The mechanisms underlying these protective effects could be related via activation of nuclear factor (erythroid-derived 2)-like (Nrf2)/heme oxygenase 1 (HO-1) and inhibition of nuclear factor kappa-B (NF-κB), mitogen-activated protein kinases (MAPKs), and Janus kinase/signal transducer and activation of transcription (JAK2/STAT3) signaling pathways. In addition, LA inhibited non-canonical and canonical activation of a nucleotide-binding (NOD)-like receptor (NLRP3) inflammasome. We conclude that LA showed significant antioxidant and anti-inflammatory activities in LPS-stimulated murine peritoneal macrophages. However, further in vivo studies are warranted to further investigate the bioactivity of this interesting compound that might be a promising natural agent for the treatment of immune-inflammatory diseases.

San-Zhong-Kui-Jian-Tang Exerts Antitumor Effects Associated With Decreased Cell Proliferation and Metastasis by Targeting ERK and the Epithelial-Mesenchymal Transition Pathway in Oral Cavity Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is an aggressive cancer whose 5-year survival rate remains poor. San-Zhong-Kui-Jian-Tang (SZKJT), a Chinese herbal formula, has long been used in clinical practice as adjuvant therapy in cancers. However, its therapeutic effects and molecular mechanisms in OSCC remain unclear. We investigated the potential therapeutic effects and molecular mechanism of SZKJT in OSCC in tumor cell lines and in tumor xenograft mice and evaluated combined SZKJT and cisplatin treatment efficacy. In vitro-cultured OSCC cells were administered SZKJT at different doses or SZKJT plus cisplatin, and cell proliferation, colony formation assays, and cell cycle analysis were used to assess the effects on cancer cell proliferation and apoptosis. We also analyzed the effects of SZKJT on oral cancer cell line migration, the regulation of mitogen-activated protein kinase (MAPK) signaling, and epithelial-mesenchymal transition (EMT)-associated genes. The antitumor effects of SZKJT plus cisplatin were also tested in vivo using a tumor-bearing NOD/SCID mice model. The results showed that SZKJT effectively inhibited OSCC cell proliferation, induced cell cycle S phase arrest, and induced cell apoptosis. SZKJT also inhibited cell migration by modulating the MAPK signaling and epithelial-mesenchymal transition (EMT) pathway. Further exploration suggested that SZKJT affects OSCC by modulating ERK pathway; downregulating vimentin, fibronectin, and Oct-4; and upregulating E-cadherin. In vivo, SZKJT significantly inhibited tumor growth, and SZKJT and cisplatin exerted synergistic antitumor effects in model animals. SZKJT exerts antitumor effects in OSCC cells. Additionally, SZKJT and cisplatin exhibit synergy in OSCC treatment. These findings support the clinical usage of Chinese herbal formulas as adjuvant therapy with chemotherapy in cancer treatment.

Characterization of Type 1 Angiotensin II Receptor Activation Induced Dual-Specificity MAPK Phosphatase Gene Expression Changes in Rat Vascular Smooth Muscle Cells.

Activation of the type I angiotensin receptor (AT1-R) in vascular smooth muscle cells (VSMCs) plays a crucial role in the regulation of blood pressure; however, it is also responsible for the development of pathological conditions such as vascular remodeling, hypertension and atherosclerosis. Stimulation of the VSMC by angiotensin II (AngII) promotes a broad variety of biological effects, including gene expression changes. In this paper, we have taken an integrated approach in which an analysis of AngII-induced gene expression changes has been combined with the use of small-molecule inhibitors and lentiviral-based gene silencing, to characterize the mechanism of signal transduction in response to AngII stimulation in primary rat VSMCs. We carried out Affymetrix GeneChip experiments to analyze the effects of AngII stimulation on gene expression; several genes, including DUSP5, DUSP6, and DUSP10, were identified as upregulated genes in response to stimulation. Since various dual-specificity MAPK phosphatase (DUSP) enzymes are important in the regulation of mitogen-activated protein kinase (MAPK) signaling pathways, these genes have been selected for further analysis. We investigated the kinetics of gene-expression changes and the possible signal transduction processes that lead to altered expression changes after AngII stimulation. Our data shows that the upregulated genes can be stimulated through multiple and synergistic signal transduction pathways. We have also found in our gene-silencing experiments that epidermal growth factor receptor (EGFR) transactivation is not critical in the AngII-induced expression changes of the investigated genes. Our data can help us understand the details of AngII-induced long-term effects and the pathophysiology of AT1-R. Moreover, it can help to develop potential interventions for those symptoms that are induced by the over-functioning of this receptor, such as vascular remodeling, cardiac hypertrophy or atherosclerosis.

Network Pharmacology-Based Analysis of the Underlying Mechanism of Hyssopus cuspidatus Boriss. for Antiasthma: A Characteristic Medicinal Material in Xinjiang.

Background Hyssopus cuspidatus Boriss. (Shen Xiang Cao (SXC)), a traditional medicine herb in Xinjiang, has a long history of being used by minorities to treat asthma. However, its active antiasthmatic compounds and underlying mechanism of action are still unknown. The aim of this study was to investigate the bioactive compounds and explore the molecular mechanism of SCX in the treatment of asthma using network pharmacology. Methods The compounds of SCX were collected by a literature search, and Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and SwissTargetPrediction were used to predict targets and screen active compounds. Moreover, asthma-related targets were obtained based on DisGeNET, Herb, and GeneCards databases, and a protein-protein interaction (PPI) network was built by the STRING database. Furthermore, the topological analysis of the PPI and SXC-compound-target networks were analyzed and established by Cytoscape software. Finally, the RStudio software package was used for carrying out Gene Ontology (GO) function enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. AutoDock tools and AutoDock Vina were used to molecularly dock the active compounds and key targets. Results A total of 8 active compounds and 258 potential targets related to SXC were predicted, and PPI network screened out key targets, including IL-6, JUN, TNF, IL10, and CXCL8. GO enrichment analysis involved cell responses to reactive oxygen species, oxidative stress, chemical stress, etc. In addition, KEGG pathway analysis showed that SXC effectively treated asthma through regulation of mitogen-activated protein kinases (MAPK) signaling pathways, interleukin 17 (IL-17) signaling pathways, toll-like receptor (TLR) signaling pathways, and tumor necrosis factor (TNF) signaling pathways. Conclusion The preliminary study that was based on multiple compounds, multiple targets, and multiple pathways provides a scientific basis for further elucidating the molecules involved and the underlying antiasthma-related mechanisms of SXC.

A New Paradigm for KIM-PTP Drug Discovery: Identification of Allosteric Sites with Potential for Selective Inhibition Using Virtual Screening and LEI Analysis.

The kinase interaction motif protein tyrosine phosphatases (KIM-PTPs), HePTP, PTPSL and STEP, are involved in the negative regulation of mitogen-activated protein kinase (MAPK) signalling pathways and are important therapeutic targets for a number of diseases. We have used VSpipe, a virtual screening pipeline, to identify a ligand cluster distribution that is unique to this subfamily of PTPs. Several clusters map onto KIM-PTP specific sequence motifs in contrast to the cluster distribution obtained for PTP1B, a classic PTP that mapped to general PTP motifs. Importantly, the ligand clusters coincide with previously reported functional and substrate binding sites in KIM-PTPs. Assessment of the KIM-PTP specific clusters, using ligand efficiency index (LEI) plots generated by the VSpipe, ascertained that the binders in these clusters reside in a more drug-like chemical–biological space than those at the active site. LEI analysis showed differences between clusters across all KIM-PTPs, highlighting a distinct and specific profile for each phosphatase. The most druggable cluster sites are unexplored allosteric functional sites unique to each target. Exploiting these sites may facilitate the delivery of inhibitors with improved drug-like properties, with selectivity amongst the KIM-PTPs and over other classical PTPs.

Melatonin as a Potential Regulator of Oxidative Stress, and Neuroinflammation: Mechanisms and Implications for the Management of Brain Injury-Induced Neurodegeneration

This review covers the preclinical and clinical literature supporting the role of melatonin in the management of brain injury-induced oxidative stress, neuroinflammation, and neurodegeneration, and reviews the past and current therapeutic strategies. Traumatic brain injury (TBI) is a neurodegenerative condition, unpredictably and potentially progressing into chronic neurodegeneration, with permanent cognitive, neurologic, and motor dysfunction, having no standard therapies. Due to its complex and multi-faceted nature, the TBI has highly heterogeneous pathophysiology, characterized by the highest mortality and disability worldwide. Mounting evidence suggests that the TBI induces oxidative and nitrosative stress, which is involved in the progression of chronic and acute neurodegenerative diseases. Defenses against such conditions are mostly dependent on the usage of antioxidant compounds, the majority of whom are ingested as nutraceuticals or as dietary supplements. A large amount of literature is available regarding the efficacy of antioxidant compounds to counteract the TBI-associated damage in animal and cellular models of the TBI and several clinical studies. Collectively, the studies have suggested that TBI induces oxidative stress, by suppressing the endogenous antioxidant system, such as nuclear factor erythroid 2–related factor-2 (Nrf-2) increasing the lipid peroxidation and elevation of oxidative damage. Moreover, elevated oxidative stress may induce neuroinflammation by activating the microglial cells, releasing and activating the inflammatory cytokines and inflammatory mediators, and energy dyshomeostasis. Thus, melatonin has shown regulatory effects against the TBI-induced autophagic dysfunction, regulation of mitogen-activated protein kinases, such as ERK, activation of the NLRP-3 inflammasome, and release of the inflammatory cytokines. The collective findings strongly suggest that melatonin may regulate TBI-induced neurodegeneration, although further studies should be conducted to better facilitate future therapeutic windows.

DUSP9, a Dual-Specificity Phosphatase with a Key Role in Cell Biology and Human Diseases.

Mitogen-activated protein kinases (MAPKs) are essential for proper cell functioning as they regulate many molecular effectors. Careful regulation of MAPKs is therefore required to avoid MAPK pathway dysfunctions and pathologies. The mammalian genome encodes about 200 phosphatases, many of which dephosphorylate the MAPKs and bring them back to an inactive state. In this review, we focus on the normal and pathological functions of dual-specificity phosphatase 9 (DUSP9)/MAP kinase phosphatases-4 (MKP-4). This cytoplasmic phosphatase, which belongs to the threonine/tyrosine dual-specific phosphatase family and was first described in 1997, is known to dephosphorylate ERK1/2, p38, JNK and ASK1, and thereby to control various MAPK pathway cascades. As a consequence, DUSP9 plays a major role in human pathologies and more specifically in cardiac dysfunction, liver metabolic syndromes, diabetes, obesity and cancer including drug response and cell stemness. Here, we recapitulate the mechanism of action of DUSP9 in the cell, its levels of regulation and its roles in the most frequent human diseases, and discuss its potential as a therapeutic target.

Loss of DUSP4 Expression as a Prognostic Biomarker in Clear Cell Renal Cell Carcinoma.

Dual-specificity protein phosphatase 4 (DUSP4) is a negative regulator of mitogen-activated protein kinases. The prognostic impact of DUSP4 expression in renal cell carcinoma is not well studied. Therefore, we evaluated the clinicopathological implications of DUSP4 expression in clear cell renal cell carcinoma by performing immunohistochemistry (IHC). The clinical outcome according to DUSP4 expression was evaluated through survival analyses, and the association between mRNA expression and prognosis was confirmed by online analysis (Kaplan–Meier plotter). Loss of DUSP4 expression was noted in most histological subtypes of renal cell carcinoma. Loss of DUSP4 expression in clear cell renal cell carcinoma was significantly correlated with old age (p = 0.033), high histologic grade (p < 0.001), tumor necrosis (p < 0.001), and high pT category (p < 0.001). In survival analysis, loss of DUSP4 expression was associated with poor clinical outcomes in cancer-specific survival and recurrence-free survival (p = 0.010 and p = 0.007, respectively). Upon TCGA data analysis, patients with low DUSP4 mRNA expression showed a shorter overall survival (p = 0.023). These results suggest that loss of DUSP4 expression can be used as a potential biomarker for predicting clinical outcomes in clear cell renal cell carcinoma patients.

MiRNA: Involvement of the MAPK Pathway in Ischemic Stroke. A Promising Therapeutic Target.

Ischemic stroke (IS) is a cerebrovascular disease with a high rate of disability and mortality. It is classified as the second leading cause of death that arises from the sudden occlusion of small vessels in the brain with consequent lack of oxygen and nutrients in the brain tissue. Following an acute ischemic event, the cascade of events promotes the activation of multiple signaling pathways responsible for irreversible neuronal damage. The mitogen-activated protein kinase (MAPK) signaling pathway transmits signals from the cell membrane to the nucleus in response to different stimuli, regulating proliferation, differentiation, inflammation, and apoptosis. Several lines of evidence showed that MAPK is an important regulator of ischemic and hemorrhagic cerebral vascular disease; indeed, it can impair blood–brain barrier (BBB) integrity and exacerbate neuroinflammation through the release of pro-inflammatory mediators implementing neurovascular damage after ischemic stroke. This review aims to illustrate the miRNAs involved in the regulation of MAPK in IS, in order to highlight possible targets for potential neuroprotective treatments. We also discuss some miRNAs (miR), including miR-145, miR-137, miR-493, and miR-126, that are important as they modulate processes such as apoptosis, neuroinflammation, neurogenesis, and angiogenesis through the regulation of the MAPK pathway in cerebral IS. To date, limited drug therapies are available for the treatment of IS; therefore, it is necessary to implement preclinical and clinical studies aimed at discovering novel therapeutic approaches to minimize post-stroke neurological damage.

Mitogen-activated protein kinase signaling in childhood asthma development and environment-mediated protection.

While childhood asthma prevalence is rising in Westernized countries, farm children are protected. The mitogen-activated protein kinase (MAPK) pathway with its negative regulator dual-specificity phosphatase-1 (DUSP1) is presumably associated with asthma development. We aimed to investigate the role of MAPK signaling in childhood asthma and its environment-mediated protection, including a representative selection of 232 out of 1062 children from two cross-sectional cohorts and one birth cohort study. Peripheral blood mononuclear cells (PBMC) from asthmatic and healthy children were cultured upon stimulation with farm-dust extracts or lipopolysaccharide. In subgroups, gene expression was analyzed by qPCR (PBMCs, cord blood) and NanoString technology (dendritic cells). Protein expression of phosphorylated MAPKs was measured by mass cytometry. Histone acetylation was investigated by chromatin immunoprecipitation. Asthmatic children expressed significantly less DUSP1 (p=.006) with reduced acetylation at histone H4 (p=.012) compared with healthy controls. Farm-dust stimulation upregulated DUSP1 expression reaching healthy levels and downregulated inflammatory MAPKs on gene and protein levels (PBMCs; p≤.01). Single-cell protein analysis revealed downregulated pMAPKs upon farm-dust stimulation in B cells, NK cells, monocytes, and T-cell subpopulations. Lower DUSP1 baseline levels in asthmatic children and anti-inflammatory regulation of MAPK in several immune cell types by farm-dust stimulation indicate a regulatory function for DUSP1 for future therapy contributing to anti-inflammatory characteristics of farming environments.

Osteoblasts Regulate the Expression of ADAMTS and MMPs in Chondrocytes through ERK Signaling Pathway.

Degradative enzymes such as matrix metalloproteinase (MMP) and disintegrin metalloproteinase with platelet thrombin-sensitive protein-like motifs (ADAMTS) play a key role in the development of osteoarthritis (OA). We aimed to investigate the effects of OA subchondral osteoblasts on the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 in chondrocytes and the regulation of mitogen-activated protein kinase (MAPK) signaling pathway. A rat knee OA model was constructed by cutting the anterior cruciate ligament of the knee joints, and normal rat articular cartilage chondrocytes (N-ACC), OA rat articular cartilage chondrocytes (O-ACC), normal subchondral bone osteoblasts (N-SBO), and OA subchondral bone osteoblasts (O-SBO) were isolated and extracted. The expressions of O-ACC and O-SBO COL1 and COL2 were detected respectively. Chondrocytes were identified by immunofluorescence of COL2 and toluidine blue staining, and osteoblasts were identified by COL1 immunofluorescence, alkaline phosphatase (ALP), and Alizarin Red staining. Gene expression of COL1, COL2, and aggrecan in normal chondrocytes and OA chondrocytes, and gene expression of osteoblast ALP and osteocalcin (OCN) were detected by RT-PCR to identify the two chondrocytes and the two osteoblast phenotypes. The constructing N-ACC group, O-ACC group, N-ACC + N-SBO group, N-ACC + O-SBO group, O-ACC + N-SBO group, O-ACC + O-SBO group, I+ N-ACC + O-SBO group, and I + O-ACC + O-SBO group cell cultures, and the expression of ERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes in chondrocytes cultured for 0, 24, 48, and 72 h were detected by RT-PCR. The protein expressions of pERK, ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 were detected by Western blot. · The X-ray showed that the knee joint space of the affected limb became narrow.. · The results of RT-PCR of COL2 and aggrecan gene in OA and normal chondrocytes suggest that the relative expression of COL2 in OA articular chondrocytes (0.24 ± 0.07) issignificantly lower than that in normal cartilage (0.61 ± 0.07) (p < 0.05). The relative expression of AGG (0.37 ± 0.16) in OA chondrocytes was significantly lower than that of normal chondrocytes AGG (1.30 ± 0.25) (p < 0.05). The expression of COL1 was very low, and was not statistically significant.. · The results of RT-PCR of the osteoblast ALP and OCN gene indicated that gene expression of ALP (12.30 ± 1.17) and OCN (20.47 ± 4.19)was upregulated when compared with the relative expression of ALP (4.66 ± 0.71) (p < 0.05) and OCN (12.17 ± 2.76) (p < 0.05) in normal osteoblasts, indicating that osteoblasts of OA have greater osteogenic potential than normal osteoblasts.. · The expressions of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes and proteins in OA chondrocytes or normal chondrocytes were basically unchanged when they were cocultured with normal osteoblasts. Indirect coculture of OA osteoblasts and chondrocytes could promote the expression of ADAMTS4, ADAMTS5, MMP-3, MMP-9, and MMP-13 genes and proteins in chondrocytes. Overexpression of ADAMTS and MMP in coculture systems can be reversed by MAPK-ERK inhibitors.. · OA subchondral bone osteoblasts can promote the overexpression of ADAMTS and MMPs in chondrocytes.. · The ERK signaling pathway may be involved in the regulation of the effect of subchondral bone osteoblasts on chondrocytes..