Regulation Of Mitogen-activated Protein Kinase Research Articles

Hemozoin induces malaria via activation of DNA damage, p38 MAPK and neurodegenerative pathways in a human iPSC-derived neuronal model of cerebral malaria

Malaria caused by Plasmodium falciparum infection results in severe complications including cerebral malaria (CM), in which approximately 30% of patients end up with neurological sequelae. Sparse in vitro cell culture-based experimental models which recapitulate the molecular basis of CM in humans has impeded progress in our understanding of its etiology. This study employed healthy human induced pluripotent stem cells (iPSCs)-derived neuronal cultures stimulated with hemozoin (HMZ) - the malarial toxin as a model for CM. Secretome, qRT-PCR, Metascape, and KEGG pathway analyses were conducted to assess elevated proteins, genes, and pathways. Neuronal cultures treated with HMZ showed enhanced secretion of interferon-gamma (IFN-γ), interleukin (IL)1-beta (IL-1β), IL-8 and IL-16. Enrichment analysis revealed malaria, positive regulation of cytokine production and positive regulation of mitogen-activated protein kinase (MAPK) cascade which confirm inflammatory response to HMZ exposure. KEGG assessment revealed up-regulation of malaria, MAPK and neurodegenerative diseases-associated pathways which corroborates findings from previous studies. Additionally, HMZ induced DNA damage in neurons. This study has unveiled that exposure of neuronal cultures to HMZ, activates molecules and pathways similar to those observed in CM and neurodegenerative diseases. Furthermore, our model is an alternative to rodent experimental models of CM.

Inhibiting Effect and Mechanism of Aconitum tanguticum (Maxim.) Stapf on Intestinal Fibrosis of CCD-18Co Cells

Abstract Objective: The objective of the study was to explore the potential signaling mechanism of Aconitum tanguticum (Maxim.) Stapf (ATS) and its impact on intestinal fibrosis in vitro. Methods: Network pharmacology was used to screen the active components of ATS and predict their potential targets in intestinal fibrosis. The protein–protein interaction network graph was constructed using drug–disease intersection targets retrieved from the Search Tool for Retrieval of Interacting Genes/Proteins database. The network diagram was analyzed using Cytoscape 3.6.1’stopology function. The gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were conducted using the database for annotation, visualization, and integrated discovery platform. Intestinal fibroblast model in vitro was constructed using transforming growth factor-β1 (TGF-β1)-induced CCD-18Co cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the network pharmacology-predicted antifibrotic signaling pathway of ATS and the traditional antifibrotic signaling pathway. Results: Network pharmacology revealed that there were 19 active components in ATS, suggesting that ATS could be involved in the regulation of mitogen-activated protein kinase 1 (MAPK1), PIK3CA, MAPK3, and other important targets that are present in cancer pathways, including proteoglycans, influenza A, and phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) signaling pathways. The results of quantitative reverse transcription-polymerase chain reaction (qRT-PCR) demonstrated that 0.1–1 μg/mL ATS may suppress tissue inhibitor of metalloproteinase 1, collagen I, and alpha-smooth muscle actin expression levels. The expression of the TGF-β/suppressor of the mother against decapentaplegic (Smad) and PI3K/Akt signaling pathways was controlled by ATS. In addition, ATS inhibited the PI3K/Akt pathway by reducing the expression of MAPK1, HSP90AA1, and PIK3CA. Conclusions: It has been confirmed that ATS is a multipathway and multitarget treatment for intestinal fibrosis. This study suggested that ATS might alleviate intestinal fibrosis by blocking both the TGF-β/Smad and the PI3K/Akt pathway.

The Dual-specificity Phosphatase 3 (DUSP3): A Potential Target Against Renal Ischemia/Reperfusion Injury.

Renal ischemia/reperfusion (I/R) injury is a common clinical challenge faced by clinicians in kidney transplantation. I/R is the leading cause of acute kidney injury, and it occurs when blood flow to the kidney is interrupted and subsequently restored. I/R impairs renal function in both short and long terms. Renal ischemic preconditioning refers to all maneuvers intended to prevent or attenuate ischemic damage. In this context, the present review focuses on the dual-specificity phosphatase 3 (DUSP3), also known as vaccinia H1-related phosphatase, an uncommon regulator of mitogen-activated protein kinase (MAPK) phosphorylation. DUSP3 has different biological functions: (1) it acts as a tumor modulator and (2) it is involved in the regulation of immune response, thrombosis, hemostasis, angiogenesis, and genomic stability. These functions occur either through MAPK-dependent or MAPK-independent mechanisms. DUSP3 genetic deletion dampens kidney damage and inflammation caused by I/R in mice, suggesting DUSP3 as a potential target for preventing renal I/R injury. Here, we discuss the putative role of DUSP3 in ischemic preconditioning and the potential mechanisms of such an attenuated inflammatory response via improved kidney perfusion and adequate innate immune response.

Effects of nitrous oxide and ketamine on electrophysiological and molecular responses in the prefrontal cortex of mice: A comparative study

Nitrous oxide (N2O; laughing gas) has recently reported to produce rapid antidepressant effects, but little is known about the underlying mechanisms. We performed transcriptomics, in situ hybridization, and electrophysiological studies to examine the potential shared signatures induced by 1 h inhalation of 50% N2O and a single subanesthetic dose of ketamine (10 mg/kg, i.p.) in the medial prefrontal cortex (mPFC) in adult mice. Both treatments similarly affected the transcription of several negative regulators of mitogen-activated protein kinases (MAPKs), namely, dual specificity phosphatases (DUSPs). The effects were primarily located in the pyramidal cells. Notably, the overall effects of N2O on mRNA expression were much more prominent and widespread compared to ketamine. Ketamine caused an elevation of the spiking frequency of putative pyramidal neurons and increased gamma activity (30–100 Hz) of cortical local field potentials. However, N2O produced no such effects. Spiking amplitudes and spike-to-local field potential phase locking of putative pyramidal neurons and interneurons in this brain area showed no uniform changes across treatments. Our findings suggest that N2O and subanesthetic-dose ketamine target MAPK pathway in the mPFC but produce varying acute electrophysiological responses.

Hepatocyte-specific mitogen-activated protein kinase phosphatase 1 in sexual dimorphism and susceptibility to alcohol induced liver injury.

It is well established that females are more susceptible to the toxic effects of alcohol, although the exact mechanisms are still poorly understood. Previous studies noted that alcohol reduces the expression of mitogen-activated protein kinase phosphatase 1 (MKP1), a negative regulator of mitogen-activated protein kinases (MAPK) in the liver. However, the role of hepatocyte- specific MKP1 in the pathogenesis of alcohol-associated liver disease (ALD) remains uncharacterized. This study aimed to evaluate the role of hepatocyte-specific MKP1 in the susceptibility and sexual dimorphism in alcohol-induced liver injury. C57Bl/6 mice were used in an intragastric ethanol feeding model of alcohol-associated steatohepatitis (ASH). Hepatocyte-specific Mkp1-/- knockout and (Mkp1+/+ "f/f" male and female mice were subjected to the NIAAA chronic plus binge model. Primary mouse hepatocytes were used for in vitro studies. Liver RNA sequencing was performed on an Illumina NextSeq 500. Liver injury was evaluated by plasma alanine transaminase (ALT), hepatic ER stress and inflammation markers. Statistical analysis was carried out using ANOVA and the unpaired Student's t-test. ASH was associated with the severe injury accompanied by increased endoplasmic reticulum (ER) stress and significant downregulation of Dusp1 mRNA expression. In vitro, ethanol treatment resulted in a time-dependent decrease in Dusp1 mRNA and protein expression in primary hepatocytes in both males and females; however, this effect was significantly more pronounced in hepatocytes from females. In vivo, female mice developed more liver injury in a chronic plus binge model which was accompanied by a significant decrease in liver Dusp1 mRNA expression. In comparison, liver Dusp1 was not changed in male mice, while they developed milder injury to alcohol. Mkp1 deletion in hepatocytes led to increased alcohol induced liver injury, ER stress and inflammation in both sexes. Hepatocyte Mkp1 plays a significant role in alcohol induced liver injury. Alcohol downregulates Mkp1 expression in hepatocytes in a sex dependent manner and could play a role in sexual dimorphism in increased female susceptibility to alcohol.

Linear motif specificity in signaling through p38α and ERK2 mitogen-activated protein kinases.

Mitogen-activated protein kinase (MAPK) cascades are essential for eukaryotic cells to integrate and respond to diverse stimuli. Maintaining specificity in signaling through MAPK networks is key to coupling distinct inputs to appropriate cellular responses. Docking sites-short linear motifs found in MAPK substrates, regulators, and scaffolds-can promote signaling specificity through selective interactions, but how they do so remains unresolved. Here, we screened a proteomic library for sequences interacting with the MAPKs extracellular signal-regulated kinase 2 (ERK2) and p38α, identifying selective and promiscuous docking motifs. Sequences specific for p38α had high net charge and lysine content, and selective binding depended on a pair of acidic residues unique to the p38α docking interface. Finally, we validated a set of full-length proteins harboring docking sites selected in our screens to be authentic MAPK interactors and substrates. This study identifies features that help define MAPK signaling networks and explains how specific docking motifs promote signaling integrity.

SPRY4-dependent ERK negative feedback demarcates functional adult stem cells in the male mouse germline†.

Niche-derived growth factors support self-renewal of mouse spermatogonial stem and progenitor cells through ERK MAPK signaling and other pathways. At the same time, dysregulated growth factor-dependent signaling has been associated with loss of stem cell activity and aberrant differentiation. We hypothesized that growth factor signaling through the ERK MAPK pathway in spermatogonial stem cells is tightly regulated within a narrow range through distinct intracellular negative feedback regulators. Evaluation of candidate extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK)-responsive genes known to dampen downstream signaling revealed robust induction of specific negative feedback regulators, including Spry4, in cultured mouse spermatogonial stem cells in response to glial cell line-derived neurotrophic factor or fibroblast growth factor 2. Undifferentiated spermatogonia in vivo exhibited high levels of Spry4 mRNA. Quantitative single-cell analysis of ERK MAPK signaling in spermatogonial stem cell cultures revealed both dynamic signaling patterns in response to growth factors and disruption of such effects when Spry4 was ablated, due to dysregulation of ERK MAPK downstream of RAS. Whereas negative feedback regulator expression decreased during differentiation, loss of Spry4 shifted cell fate toward early differentiation with concomitant loss of stem cell activity. Finally, a mouse Spry4 reporter line revealed that the adult spermatogonial stem cell population in vivo is demarcated by strong Spry4 promoter activity. Collectively, our data suggest that negative feedback-dependent regulation of ERK MAPK is critical for preservation of spermatogonial stem cell fate within the mammalian testis.

Glucose-6-phosphate 1-Epimerase CrGlu6 Contributes to Development and Biocontrol Efficiency in Clonostachys chloroleuca.

Clonostachys chloroleuca (formerly classified as C. rosea) is an important mycoparasite active against various plant fungal pathogens. Mitogen-activated protein kinase (MAPK) signaling pathways are vital in mycoparasitic interactions; they participate in responses to diverse stresses and mediate fungal development. In previous studies, the MAPK-encoding gene Crmapk has been proven to be involved in mycoparasitism and the biocontrol processes of C. chloroleuca, but its regulatory mechanisms remain unclear. Aldose 1-epimerases are key enzymes in filamentous fungi that generate energy for fungal growth and development. By protein-protein interaction assays, the glucose-6-phosphate 1-epimerase CrGlu6 was found to interact with Crmapk, and expression of the CrGlu6 gene was significantly upregulated when C. chloroleuca colonized Sclerotinia sclerotiorum sclerotia. Gene deletion and complementation analyses showed that CrGlu6 deficiency caused abnormal morphology of hyphae and cells, and greatly reduced conidiation. Moreover, deletion mutants presented much lower antifungal activities and mycoparasitic ability, and control efficiency against sclerotinia stem rot was markedly decreased. When the CrGlu6 gene was reinserted, all biological characteristics and biocontrol activities were recovered. These findings provide new insight into the mechanisms of glucose-6-phosphate 1-epimerase in mycoparasitism and help to further reveal the regulation of MAPK and its interacting proteins in the biocontrol of C. chloroleuca.

Liver transcriptomic and methylomic analyses identify transcriptional mitogen-activated protein kinase regulation in facultative hibernation of Syrian hamster.

Hibernation consists of alternating torpor-arousal phases, during which animals cope with repetitive hypothermia and ischaemia-reperfusion. Due to limited transcriptomic and methylomic information for facultative hibernators, we here conducted RNA and whole-genome bisulfide sequencing in liver of hibernating Syrian hamster (Mesocricetus auratus). Gene ontology analysis was performed on 844 differentially expressed genes and confirmed the shift in metabolic fuel utilization, inhibition of RNA transcription and cell cycle regulation as found in seasonal hibernators. Additionally, we showed a so far unreported suppression of mitogen-activated protein kinase (MAPK) and protein phosphatase 1 pathways during torpor. Notably, hibernating hamsters showed upregulation of MAPK inhibitors (dual-specificity phosphatases and sproutys) and reduced levels of MAPK-induced transcription factors (TFs). Promoter methylation was found to modulate the expression of genes targeted by these TFs. In conclusion, we document gene regulation between hibernation phases, which may aid the identification of pathways and targets to prevent organ damage in transplantation or ischaemia-reperfusion.

Anti-Inflammatory Effects of New Naphthyridine from sponge Aaptos suberitoides in LPS-Stimulated RAW 264.7 Macrophages via Regulation of MAPK and Nrf2 Signaling Pathways.

Two new naphthyridine compounds, 4-carbomethoxy-5-keto-1,6-naphthyridine (1) and 4-keto-5-carbomethoxy-1,6-naphthyridine (2) were obtained from the MeOH extracts of sponge Aaptos suberitoides. Their structures were determined by spectroscopic methods, including HR-ESI-MS, 1D-NMR (1H-NMR, 13C-NMR), 2D-NMR (COSY, HSQC, HMBC). The structure of compound 1 was further confirmed via single crystal X-ray diffraction analysis. Compound 1 was found to reduce NO production in LPS-induced RAW 264.7 macrophages with IC50 value of 0.15 mM. In addition, it decreased the mRNA expression levels of pro-inflammatory mediators, such as the tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) in LPS-induced macrophages. It also decreased the protein expression of iNOS and COX-2 in LPS-induced macrophages. Mechanistic studies further revealed that compound 1 inhibited the mitogen-activated protein kinase (MAPK), and activated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) signaling pathways in LPS-induced RAW 264.7 macrophages.

TAK1 MEDIATES HMGB1-INDUCED MACROPHAGE ACTIVATION IN OSTEOARTHRITIS

Osteoarthritis, the most common degenerative joint disease, significantly impairs life quality and labor capability of patients. Synovial inflammation, initiated by HMGB1 (High mobility group box 1)-induced activation of macrophage, precedes other pathological changes. As an upstream regulator of NF-κB (nuclear factor-kappa B) and MAPK (mitogen-activated protein kinase) signaling pathway, TAK1 (TGF-β activated kinase 1) participates in macrophage activation, while its function in osteoarthritis remains unveiled. This study aims to investigate the role of TAK1 in the pathogenesis of osteoarthritis via both in vitro and in vivo approaches.We performed immunohistochemical staining for TAK1 in synovial tissue, both in osteoarthritis patients and healthy control. Besides, immunofluorescence staining for F4/80 as macrophage marker and TAK1 were conducted as well. TAK1 expression was examined in RAW264.7 macrophages stimulated by HMGB1 via qPCR (Quantitative polymerase chain reaction) and Western blotting, and the effect of TAK1 inhibitor (5z-7 oxozeaenol) on TNF-α production was evaluated by immunofluorescence staining. Further, we explored the influence of intra-articular shRNA (short hairpin RNA) targeting TAK1 on collagenase-induced osteoarthritis in mice.Immunohistochemical staining confirmed significant elevation of TAK1 in osteoarthritic synovium, and immunofluorescence staining suggested macrophages as predominant residence of TAK1. In HMGB1-stimulated RAW264.7 macrophages, TAK1 expression was up-regulated both in mRNA and protein level. Besides, TAK1 inhibitor significantly impairs the production of TNF-α by macrophages upon HMGB1 stimulation. Moreover, intra-articular injection of lentivirus loaded with shRNA targeting TAK1 (sh-TAK1) reduced peri-articular osteophyte formation in collagenase-induced osteoarthritis in mice.TAK1 exerts a potent role in the pathogenesis of osteoarthritis by mediating the activation of macrophages.

Transcriptome Dynamics Underlying Planticine®-Induced Defense Responses of Tomato (Solanum lycopersicum L.) to Biotic Stresses

The induction of natural defense mechanisms in plants is considered to be one of the most important strategies used in integrated pest management (IPM). Plant immune inducers could reduce the use of chemicals for plant protection and their harmful impacts on the environment. Planticine® is a natural plant defense biostimulant based on oligomers of α(1→4)-linked D-galacturonic acids, which are biodegradable and nontoxic. The aim of this study was to define the molecular basis of Planticine's biological activity and the efficacy of its use as a natural plant resistance inducer in greenhouse conditions. Three independent experiments with foliar application of Planticine® were carried out. The first experiment in a climatic chamber (control environment, no pest pressure) subjected the leaves to RNA-seq analysis, and the second and third experiments in greenhouse conditions focused on efficacy after a pest infestation. The result was the RNA sequencing of six transcriptome libraries of tomatoes treated with Planticine® and untreated plants; a total of 3089 genes were found to be differentially expressed genes (DEGs); among them, 1760 and 1329 were up-regulated and down-regulated, respectively. DEG analysis indicated its involvement in such metabolic pathways and processes as plant-pathogen interaction, plant hormone signal transduction, MAPK signaling pathway, photosynthesis, and regulation of transcription. We detected up-regulated gene-encoded elicitor and effector recognition receptors (ELRR and ERR), mitogen-activated protein kinase (MAPKs) genes, and transcription factors (TFs), i.e., WRKY, ERF, MYB, NAC, bZIP, pathogenesis-related proteins (PRPs), and resistance-related metabolite (RRMs) genes. In the greenhouse trials, foliar application of Planticine® proved to be effective in reducing the infestation of tomato leaves by the biotrophic pathogen powdery mildew and in reducing feeding by thrips, which are insect herbivores. Prophylactic and intervention use of Planticine® at low infestation levels allows the activation of plant defense mechanisms.

Photoprotective Effects of Dendrobium nobile Lindl. Polysaccharides against UVB-Induced Oxidative Stress and Apoptosis in HaCaT Cells

Acute ultraviolet (UV)-B radiation is the major external factor causing photodamage. In this study, we aimed to determine the effects of Dendrobium nobile Lindl. polysaccharides (DNPs) on photodamage in HaCaT keratinocytes after UVB irradiation and the underlying mechanisms. We found that DNPs significantly attenuated the decline in the viability and proliferation of HaCaT cells after UVB irradiation. Moreover, DNPs scavenged reactive oxygen species (ROS), improved the activities of endogenous antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, and reduced the levels of malondialdehyde, while partially attenuating cell cycle arrest, suggesting their antioxidant and anti-apoptotic properties. The mitogen-activated protein kinase (MAPK) pathway was found to be important for the attenuation of UVB-induced photodamage in the HaCaT cells. Furthermore, DNPs exerted cytoprotective effects by downregulating UVB-induced ROS-mediated phosphorylation of MAPKs, including p38, c-Jun N-terminal kinase, and extracellular signal-regulated kinase, and by inhibiting p53 expression as well as the apoptotic cascade response. Therefore, DNPs ameliorated UVB-induced oxidative damage and apoptosis in HaCaT cells via the regulation of MAPKs. Our findings thus highlight the Dendrobium nobile Lindl polysaccharides as promising therapeutic candidates for UVB-induced photodamage.

MicroRNAs and MAPKs: Evidence of These Molecular Interactions in Alzheimer’s Disease

Alzheimer's disease (AD) is a neurodegenerative disorder known to be the leading cause of dementia worldwide. Many microRNAs (miRNAs) were found deregulated in the brain or blood of AD patients, suggesting a possible key role in different stages of neurodegeneration. In particular, mitogen-activated protein kinases (MAPK) signaling can be impaired by miRNA dysregulation during AD. Indeed, the aberrant MAPK pathway may facilitate the development of amyloid-beta (Aβ) and Tau pathology, oxidative stress, neuroinflammation, and brain cell death. The aim of this review was to describe the molecular interactions between miRNAs and MAPKs during AD pathogenesis by selecting evidence from experimental AD models. Publications ranging from 2010 to 2023 were considered, based on PubMed and Web of Science databases. According to obtained data, several miRNA deregulations may regulate MAPK signaling in different stages of AD and conversely. Moreover, overexpressing or silencing miRNAs involved in MAPK regulation was seen to improve cognitive deficits in AD animal models. In particular, miR-132 is of particular interest due to its neuroprotective functions by inhibiting Aβ and Tau depositions, as well as oxidative stress, through ERK/MAPK1 signaling modulation. However, further investigations are required to confirm and implement these promising results.

Harnessing the role of mitogen-activated protein kinases against abiotic stresses in plants.

Crop plants are vulnerable to various biotic and abiotic stresses, whereas plants tend to retain their physiological mechanisms by evolving cellular regulation. To mitigate the adverse effects of abiotic stresses, many defense mechanisms are induced in plants. One of these mechanisms is the mitogen-activated protein kinase (MAPK) cascade, a signaling pathway used in the transduction of extracellular stimuli into intercellular responses. This stress signaling pathway is activated by a series of responses involving MAPKKKs→MAPKKs→MAPKs, consisting of interacting proteins, and their functions depend on the collaboration and activation of one another by phosphorylation. These proteins are key regulators of MAPK in various crop plants under abiotic stress conditions and also related to hormonal responses. It is revealed that in response to stress signaling, MAPKs are characterized as multigenic families and elaborate the specific stimuli transformation as well as the antioxidant regulation system. This pathway is directed by the framework of proteins and stopping domains confer the related associates with unique structure and functions. Early studies of plant MAPKs focused on their functions in model plants. Based on the results of whole-genome sequencing, many MAPKs have been identified in plants, such as Arbodiposis, tomato, potato, alfalfa, poplar, rice, wheat, maize, and apple. In this review, we summarized the recent work on MAPK response to abiotic stress and the classification of MAPK cascade in crop plants. Moreover, we highlighted the modern research methodologies such as transcriptomics, proteomics, CRISPR/Cas technology, and epigenetic studies, which proposed, identified, and characterized the novel genes associated with MAPKs and their role in plants under abiotic stress conditions. In-silico-based identification of novel MAPK genes also facilitates future research on MAPK cascade identification and function in crop plants under various stress conditions.

Genistein Promotes Anti-Heat Stress and Antioxidant Effects via the Coordinated Regulation of IIS, HSP, MAPK, DR, and Mitochondrial Pathways in Caenorhabditis elegans.

To determine the anti-heat stress and antioxidant effects of genistein and the underlying mechanisms, lipofuscin, reactive oxygen species (ROS), and survival under stress were first detected in Caenorhabditis elegans (C. elegans); then the localization and quantification of the fluorescent protein was determined by detecting the fluorescently labeled protein mutant strain; in addition, the aging-related mRNAs were detected by applying real-time fluorescent quantitative PCR in C. elegans. The results indicate that genistein substantially extended the lifespan of C. elegans under oxidative stress and heat conditions; and remarkably reduced the accumulation of lipofuscin in C. elegans under hydrogen peroxide (H2O2) and 35 °C stress conditions; in addition, it reduced the generation of ROS caused by H2O2 and upregulated the expression of daf-16, ctl-1, hsf-1, hsp-16.2, sip-1, sek-1, pmk-1, and eat-2, whereas it downregulated the expression of age-1 and daf-2 in C. elegans; similarly, it upregulated the expression of daf-16, sod-3, ctl-1, hsf-1, hsp-16.2, sip-1, sek-1, pmk-1, jnk-1 skn-1, and eat-2, whereas it downregulated the expression of age-1, daf-2, gst-4, and hsp-12.6 in C. elegans at 35 °C; moreover, it increased the accumulation of HSP-16.2 and SKN-1 proteins in nematodes under 35 °C and H2O2 conditions; however, it failed to prolong the survival time in the deleted mutant MQ130 nematodes under 35 °C and H2O2 conditions. These results suggest that genistein promote anti-heat stress and antioxidant effects in C. elegans via insulin/-insulin-like growth factor signaling (IIS), heat shock protein (HSP), mitogen-activated protein kinase (MAPK), dietary restriction (DR), and mitochondrial pathways.

Relationship Between Obesity and Hypertension From Bioinformatics Analysis

Abstract Background To explore the relationship between obesity and hypertension using bioinformatics analyses. Methods Disease databases (GeneCards, OMIM, CTD, TTD, DisGeNET, and Drugbank) were used to obtain hypertension and obesity-related targets. The intersection targets of obesity and hypertension were constructed using Venn diagrams. STRING online platform was used to obtain protein–protein interaction networks of common targets, and Cytohubba plug-in was used to screen the core targets. Gene ontology (GO) analysis and the enrichment analysis of Kyoto encyclopedia of genes and genomes (KEGG) were carried out using DAVID database. Results A total of 459 and 551 targets were obtained for obesity and hypertension, respectively. Among them, 135 were targets for both obesity and hypertension in which tumor necrosis factor (TNF), cell tumor antigen p53 (TP53), chemokine 2 (CCL2), Toll-like receptor 4 (TLR4), interleukin (IL) 1B, nitric oxide synthase 3 (NOS3), IL-6, and serine/threonine protein kinase 1 (AKT1) were key targets for regulating obesity and hypertension. Enrichment analysis yielded 306 GO entries [P < 0.05, false discovery rate (FDR) <0.05], which were involved in positive regulation of mitogen-activated protein kinase (MAPK) cascade, positive regulation of nitric oxide biosynthetic process, cilium basal body, hormone activity, and RNA polymerase II repeating transcription factor binding. The 86 enriched KEGG entries (P < 0.05, FDR <0.05) included adipocytokine signaling pathway, regulation of lipolysis in adipocytes, PI3K–Akt signaling pathway and forkhead transcription factor O (FoxO) signaling pathway. Conclusions TNF, TP53, CCL2, TLR4, IL-1B, NOS3, IL-6, AKT1, and the key pathways including adipocytokine signaling pathway, regulation of adipocyte lipolysis, PI3K–Akt and FoxO signaling pathway play a regulatory role in interactions between obesity and hypertension. These findings provide new insights into the complex interactions between obesity and hypertension.

The GhMAP3K62-GhMKK16-GhMPK32 kinase cascade regulates drought tolerance by activating GhEDT1-mediated ABA accumulation in cotton

IntroductionDrought is the principal abiotic stress that severely impacts cotton (Gossypium hirsutum) growth and productivity. Upon sensing drought, plants activate stress-related signal transduction pathways, including ABA signal and mitogen-activated protein kinase (MAPK) cascade. However, as the key components with the fewest members in the MAPK cascade, the function and regulation of GhMKKs need to be elucidated. In addition, the relationship between MAPK module and the ABA core signaling pathway remains incompletely understood. ObjectiveHere we aim to elucidate the molecular mechanism of cotton response to drought, with a focus on mitogen-activated protein kinase (MAPK) cascades activating ABA signaling. MethodsBiochemical, molecular and genetic analysis were used to study the GhMAP3K62-GhMKK16-GhMPK32-GhEDT1 pathway genes. ResultsA nucleus- and membrane-localized MAPK cascade pathway GhMAP3K62-GhMKK16-GhMPK32, which targets and phosphorylates the nuclear-localized transcription factor GhEDT1, to activate downstream GhNCED3 to mediate ABA-induced stomatal closure and drought response was characterized in cotton. Overexpression of GhMKK16 promotes ABA accumulation, and enhances drought tolerance via regulating stomatal closure under drought stress. Conversely, RNAi-mediated knockdown of GhMKK16 expression inhibits ABA accumulation, and reduces drought tolerance. Virus-induced gene silencing (VIGS)-mediated knockdown of either GhMAP3K62, GhMPK32 or GhEDT1 expression represses ABA accumulation and reduces drought tolerance through inhibiting stomatal closure. Expression knockdown of GhMPK32 or GhEDT1 in GhMKK16-overexpressing cotton reinstates ABA content and stomatal opening-dependent drought sensitivity to wild type levels. GhEDT1 could bind to the HD boxes in the promoter of GhNCED3 to activate its expression, resulting in ABA accumulation. We propose that the MAPK cascade GhMAP3K62-GhMKK16-GhMPK32 pathway functions on drought response through ABA-dependent stomatal movement in cotton.

473 DUSP4-DUSP6 axis contributes to sustained ERK activity and high proliferation of the melanoma cells

A subset of dual-specificity phosphatases (DUSPs) act as major negative regulators of mitogen-activated protein kinases (MAPKs), and their possible involvement in tumorigenesis has been suggested. Among them, DUSP4 preferentially dephosphorylates ERK1/2 and Jnk over p38. In the present study, we aimed to identify the possible role of DUSP4 in melanomagenesis. Examination of publicly available large-scale data on cancer cell-lines revealed a remarkably high DUSP4 expression and dependency of most melanoma cell lines compared with other tumor-derived cell lines. No such high gene dependency specific to melanoma cells was evident for the other 24 DUSPs encoded in the human genome. Using two melanoma cell lines SK-MEL-28 and A375 as representatives, we confirmed that DUSP4 depletion impaired cell growth without notably inducing apoptosis for up to several days. Immunoblotting and kinase translocation reporter assay showed that the depletion simultaneously induced a decrease, not an increase, in ERK1/2 phosphorylation and an increase in DUSP6 protein level and that it barely affected Jnk phosphorylation. This observation indicates that neither ERK nor Jnk was a direct target of DUSP4 in our experimental setting. Quantitation of DUSP6 mRNA suggested that change in DUSP6 protein level mainly occurred through a post-transcriptional process, although it is not clear whether this took place by an increase in translation rate or inhibition of degradation kinetics. CRISPR/CAS9-mediated knock-out of DUSP6 mostly eliminated a decrease in the ERK phosphorylation and growth retardation following DUSP4 depletion suggesting the existence of the DUSP4-DUSP6-ERK serial regulation pathway. Our data support a model that DUSP4 plays a role in maintaining high ERK1/2 activity by negatively regulating DUSP6, thus contributing to the survival and growth of melanoma cells.

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