Mitogen-activated Protein Kinase Pathway Research Articles

S-palmitoylation of MAP kinase is essential for fungal virulence.

S-palmitoylation is an important reversible protein post-translational modification in organisms. However, its role in fungi is uncertain. Here, we found the treatment of the rice false fungus Ustilaginoidea virens with S-palmitoylation inhibitor 2 BP resulted in a significant decrease in fungal virulence. Comprehensive identification of S-palmitoylation sites and proteins in U. virens revealed a total of 4,089 S-palmitoylation sites identified among 2,192 proteins and that S-palmitoylated proteins were involved in diverse biological processes. Among the five palmitoyltransferases, UvPfa3 and UvPfa4 were found to regulate the pathogenicity of U. virens. We then performed quantitative proteomic analysis of ∆UvPfa3 and ∆UvPfa4 mutants. Interestingly, S-palmitoylated proteins were significantly enriched in the mitogen-activated protein kinase and autophagy pathways, and MAP kinase UvSlt2 was confirmed to be an S-palmitoylated protein which was palmitoylated by UvPfa4. Mutations of S-palmitoylation sites in UvSlt2 resulted in significantly reduced fungal virulence and decreased kinase enzymatic activity and phosphorylation levels. Simulations of molecular dynamics demonstrated mutation of S-palmitoylation sites in UvSlt2 causing decreased hydrophobic solvent-accessible surface area, thereby weakening the bonding force with its substrate UvRlm1. Taken together, S-palmitoylation promotes U. virens virulence through palmitoylation of MAP kinase UvSlt2 by palmitoyltransferase UvPfa4. This enhances the enzymatic phosphorylation activity of the kinase, thereby increasing hydrophobic solvent-accessible surface area and binding activity between the UvSlt2 enzyme and its substrate UvRlm1. Our studies provide a framework for dissecting the biological functions of S-palmitoylation and reveal an important role for S-palmitoylation in regulating the virulence of the pathogen.IMPORTANCES-palmitoylation is an important post-translational lipid modification of proteins. However, its role in fungi is uncertain. In this study, we found that S-palmitoylation promotes virulence of rice false smut fungus U. virens through palmitoylation of MAP kinase UvSlt2 by palmitoyltransferase UvPfa4. This enhances the enzymatic phosphorylation activity of the kinase, thereby increasing hydrophobic solvent-accessible surface area and binding activity between the UvSlt2 enzyme and its substrate UvRlm1. Our studies provide a framework for dissecting the biological functions of S-palmitoylation and reveal an important role for S-palmitoylation in regulating the virulence of the pathogen. This is the first functional study to reveal the role of S-palmitoylation in fungal virulence.

Mechanisms of Bone Morphogenetic Protein 2 in Respiratory Diseases.

Bone morphogenetic protein 2 (BMP2) belongs to the transforming growth factor-β (TGF-β) superfamily and plays an important role in regulating embryonic development, angiogenesis, osteogenic differentiation, tissue homeostasis, and cancer invasion. Increasing studies suggest BMP2 is involved in several respiratory diseases. This study aimed to review the role and mechanisms of BMP2 in respiratory diseases. BMP2 signaling pathway includes the canonical and non-canonical signaling pathway. The canonical signaling pathway is the BMP2-SMAD pathway, and the non-canonical signaling pathway includes mitogen-activated protein kinase (MAPK) pathway and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway. The BMP2 is related to pulmonary hypertension (PH), lung cancer, pulmonary fibrosis (PF), asthma, and chronic obstructive pulmonary disease (COPD). BMP2 inhibits the proliferation of pulmonary artery smooth muscle cells (PASMCs), promotes the apoptosis of PASMCs to reduce pulmonary vascular remodeling in PH, which is closely related to the canonical and non-canonical pathway. In addition, BMP2 stimulates the proliferation and migration of cells to promote the occurrence, colonization, and metastasis of lung cancer through the canonical and the non-canonical pathway. Meanwhile, BMP2 exert anti-fibrotic function in PF through canonical signaling pathway. Moreover, BMP2 inhibits airway inflammation to maintain airway homeostasis in asthma. However, the signaling pathways involved in asthma are poorly understood. BMP2 inhibits the expression of ciliary protein and promotes squamous metaplasia of airway epithelial cells to accelerate the development of COPD. In conclusion, BMP2 may be a therapeutic target for several respiratory diseases.

Probiotic Characteristics and the Anti-Inflammatory Effects of Lactiplantibacillus plantarum Z22 Isolated from Naturally Fermented Vegetables

Currently, there is increasing interest in the commercial utilization of probiotics isolated from traditional fermented food products. Therefore, this study aimed to investigate the probiotic potential of Lactiplantibacillus plantarum (L. plantarum) Z22 isolated from naturally fermented mustard. The results suggest that L. plantarum Z22 exhibits good adhesion ability, antibacterial activity, safety, and tolerance to acidic conditions and bile salts. We further determined the anti-inflammatory mechanism and properties of L. plantarum Z22 and found that L. plantarum Z22 could significantly reduce the secretion of pro-inflammatory cytokines, including interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and the expression of the pro-inflammatory mediator cyclooxygenase-2 (COX-2) protein in LPS-induced RAW 264.7 cells. In addition, L. plantarum Z22 also effectively inhibited the signaling pathways of nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs). This effect can be attributed to a decrease in the levels of reactive oxygen species (ROS) and increased heme oxygenase-1 (HO-1) expression. Moreover, whole-genome sequencing revealed that L. plantarum Z22 contains gene-encoding proteins with anti-inflammatory functions, such as beta-glucosidase (BGL) and pyruvate kinase (PK), as well as antioxidant functions, including thioredoxin reductase (TrxR), tyrosine-protein phosphatase, and ATP-dependent intracellular proteases ClpP. In summary, these results indicated that L. plantarum Z22 can serve as a potential candidate probiotic for use in fermented foods such as yogurt (starter cultures), providing a promising strategy for the development of functional foods to prevent chronic diseases.

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.

Preventive effects of matrine on LPS-induced inflammation in RAW 264.7 cells and intestinal damage in mice through the TLR4/NF-κB/MAPK pathway

BackgroundMatrine is a tetracyclic quinolizidine alkaloid with diverse bioactive properties, including anti-inflammatory and neuroprotective properties. However, the underlying anti-inflammatory mechanisms remain unclear. PurposeThis study aimed to explore how matrine reduces Lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 cells and to assess its protective effects against LPS-induced intestinal damage. MethodsThe effect of matrine on cell viability was assessed using the cell counting kit-8 (CCK-8) assay. Additionally, its impact on inflammatory cytokines and macrophage polarization was assessed using enzyme-linked immunosorbent assay (ELISA), flow cytometry, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses. The effects on intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP), nitric oxide (NO) production, and oxidative stress were evaluated using 2′,7′-dichlorodihydrofluorescein diacetate staining and JC-1 and Griess assays. Immunofluorescence staining was used to observe the translocation of the NF-κB p65 subunit. Western blotting (WB) and qRT-PCR were employed to analyze the expression levels of proteins related to the toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) pathway. An LPS-induced mouse model was established to study the intestinal inflammation and barrier injury. Mouse feces characteristics, colon length, and disease activity index (DAI) were recorded. Hematoxylin-eosin (H&E) and alcian blue/periodic acid schiff (AB/PAS) staining were used to observe morphological changes and barrier damage in the duodenum, jejunum, ileum, and colon and to measure villus length, crypt depth, goblet cell count, and positive areas in the duodenum, jejunum, and ileum. The content of short-chain fatty acids (SCFAs) in the colon was determined using gas chromatography (GC). ResultsMatrine inhibited LPS-induced inflammatory cytokine levels, suppressed macrophage M1 polarization, and promoted M2 macrophage polarization. Matrine reduced LPS-induced increases in ROS and NO levels and regulates oxidative stress. Additionally, matrine inhibited the nuclear translocation of the NF-κB p65 subunit and exerted anti-inflammatory effects by suppressing the activation of the TLR4/NF-κB/MAPK pathway. In vivo experiments indicated that matrine significantly alleviated LPS-induced diarrhea, increased DAI, and shortened the colon. Matrine reduced the production of the pro-inflammatory cytokine interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF)-α and the pro-inflammatory mediator NO in mouse intestinal tissues while promoting the content of the anti-inflammatory cytokine IL-10. Furthermore, it improved intestinal tissue structure and alleviated LPS-induced intestinal barrier damage. Finally, matrine increased the SCFA levels in the intestine. ConclusionMatrine exerted its anti-inflammatory effects and protects against intestinal injury through the TLR4/NF-κB/MAPK signaling pathway.

Immunomodulatory Effects of a Prebiotic Formula with 2'-Fucosyllactose and Galacto- and Fructo-Oligosaccharides on Cyclophosphamide (CTX)-Induced Immunosuppressed BALB/c Mice via the Gut-Immune Axis.

Obejectives: This study explored the immunomodulatory effects of a prebiotic formula consisting of 2'-fucosyllactose (2'-FL), galacto-oligosaccharides (GOSs), and fructo-oligosaccharides (FOSs) (hereinafter referred to as 2FGF) in cyclophosphamide (CTX)-induced immunosuppressed BALB/c mice and its underlying mechanisms. Methods: Sixty healthy female BALB/c mice were randomly divided into the following groups: normal control (NC) group; CTX treatment (CTX) group; 2FGF low-dose (2FGF-L) group; 2FGF medium-dose (2FGF-M) group; and 2FGF high-dose (2FGF-H) group. An immunosuppressed model was established in the 2FGF-H group by intraperitoneal injection of 80 mg/kg CTX. After 30 days of 2FGF intervention, peripheral blood, spleen tissue, thymus tissue, and intestinal tissue from the mice were collected and analyzed. The changes in weight and food intake of the mice were recorded weekly. Hematoxylin-eosin (HE) staining was used to observe the histological change of the spleen tissue. Enzyme-linked immunosorbent assay (ELISA) was employed to detect cytokine levels in peripheral blood. Flow cytometry was used to analyze T lymphocyte subgroup ratio of splenic lymphocytes. Western blot analysis was conducted on intestinal tissues to assess the expression of proteins involved in the tight junction, toll-like receptor 4 (TLR4), mitogen-activated protein kinase (MAPK), and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) signaling pathways. Additionally, molecular techniques were used to analyze the intestinal microbiota. Results: The results showed that 2FGF restored CTX-induced splenic injury, increased the number of splenic T lymphocytes, and elevated serum cytokines such as interleukin-4 (IL-4) and IL-10. In the intestine, 2FGF upregulated the expression of intestinal epithelial tight junction proteins such as Claudin-1 and zonula occludens 1 (ZO-1), thereby enhancing intestinal barrier function and activating the MAPK and NF-κB pathways via TLR4. Furthermore, 2FGF elevated the α-diversity (Shannon and Simpson indices) of the gut microbiota in CTX-induced immunosuppressed mice, enriching bacteria species positively correlated with anti-inflammatory cytokines (e.g., IL-4) such as g_Streptomyces and g_Bacillus and negatively correlated with pro-inflammatory cytokines (e.g., IL-1β) such as g_Saccharomyces. The results suggest that 2FGF may enhance immunity via the gut-immune axis. Conclusions: The 2FGF prebiotic formula showed an immunomodulatory effect in CTX-induced immunosuppressed mice, and the mechanism of which might involve optimizing the gut flora, enhancing intestinal homeostasis, strengthening the intestinal barrier, and promoting the expression of immune factors by regulating the TLR-4/MAPK/NF-κB pathway.

Distinct mechanisms of type 3 secretion system recognition control LTB4 synthesis in neutrophils and macrophages.

Leukotriene B4 (LTB4) is an inflammatory lipid produced in response to pathogens that is critical for initiating the inflammatory cascade needed to control infection. However, during plague, Yersinia pestis inhibits the timely synthesis of LTB4 and subsequent inflammation. Using bacterial mutants, we previously determined that Y. pestis inhibits LTB4 synthesis via the action of the Yop effector proteins that are directly secreted into host cells through a type 3 secretion system (T3SS). Here, we show that the T3SS is the primary pathogen associated molecular pattern (PAMP) required for production of LTB4 in response to both Yersinia and Salmonella. However, we also unexpectantly discovered that T3SS-mediated LTB4 synthesis by neutrophils and macrophages require the activation of two distinctly different host signaling pathways. We identified that phagocytosis and the NLRP3/CASP1 inflammasome significantly impact LTB4 synthesis by macrophages but not neutrophils. Instead, the SKAP2/PLC signaling pathway is required for T3SS-mediated LTB4 production by neutrophils. Finally, while recognition of the T3SS is required for LTB4 production, we also discovered that a second unrelated PAMP-mediated signal activates the MAP kinase pathway needed for synthesis. Together, these data demonstrate significant differences in the host factors and signaling pathways required by macrophages and neutrophils to quickly produce LTB4 in response to bacteria. Moreover, while macrophages and neutrophils might rely on different signaling pathways for T3SS-dependent LTB4 synthesis, Y. pestis has evolved virulence mechanisms to counteract this response by either leukocyte to inhibit LTB4 synthesis and colonize the host.

VE-1 regulation of MAPK signaling controls sexual development in Neurospora crassa.

Sexual reproduction generates new gene combinations and novel phenotypic traits and facilitates evolution. Induction of sexual development in fungi is often regulated by environmental conditions, such as the presence of light and nutrients. The velvet protein complex coordinates internal cues and environmental signals to regulate development. We have found that VE-1, a component of the velvet complex, regulates transcription during sexual development in the fungus Neurospora crassa. VE-1 regulates the transcription of many genes, including those involved in mitogen-activated protein kinase (MAPK) signaling pathways that are essential in the regulation of sexual development, and regulates the activity of the MAPK pathway. Our findings provide valuable insights into how fungi respond to environmental signals and integrate them into their reproductive processes.

PEP-1-PIN1 Promotes Hippocampal Neuronal Cell Survival by Inhibiting Cellular ROS and MAPK Phosphorylation.

Background: The peptidyl-prolyl isomerase (PIN1) plays a vital role in cellular processes, including intracellular signaling and apoptosis. While oxidative stress is considered one of the primary mechanisms of pathogenesis in brain ischemic injury, the precise function of PIN1 in this disease remains to be elucidated. Objective: We constructed a cell-permeable PEP-1-PIN1 fusion protein and investigated PIN1's function in HT-22 hippocampal cells as well as in a brain ischemic injury gerbil model. Methods: Transduction of PEP-1-PIN1 into HT-22 cells and signaling pathways were determined by Western blot analysis. Intracellular reactive oxygen species (ROS) production and DNA damage was confirmed by DCF-DA and TUNEL staining. Cell viability was determined by MTT assay. Protective effects of PEP-1-PIN1 against ischemic injury were examined using immunohistochemistry. Results: PEP-1-PIN1, when transduced into HT-22 hippocampal cells, inhibited cell death in H2O2-treated cells and markedly reduced DNA fragmentation and ROS production. This fusion protein also reduced phosphorylation of mitogen-activated protein kinase (MAPK) and modulated expression levels of apoptosis-signaling proteins in HT-22 cells. Furthermore, PEP-1-PIN1 was distributed in gerbil hippocampus neuronal cells after passing through the blood-brain barrier (BBB) and significantly protected against neuronal cell death and also decreased activation of microglia and astrocytes in an ischemic injury gerbil model. Conclusions: These results indicate that PEP-1-PIN1 can inhibit ischemic brain injury by reducing cellular ROS levels and regulating MAPK and apoptosis-signaling pathways, suggesting that PIN1 plays a protective role in H2O2-treated HT-22 cells and ischemic injury gerbil model.

Genome‑wide identification of circular RNAs and MAPKs reveals the regulatory networks in response to green peach aphid infestation in peach (Prunus persica)

The green peach aphid (GPA), Myzus persicae (Sulzer), is a serious agricultural pest with a worldwide distribution and a vector of over 100 plant viruses. Various pathways, such as the mitogen-activated protein kinase (MAPK) cascades, play pivotal roles in signaling plant defense against pest attack, and circular RNAs (circRNAs) regulate the expression of mRNAs in response to pest attack. However, the mechanism underlying peach (Prunus persica) response to GPA attack remains unclear. The present study initially identified and characterized 316 circRNAs and 18 PpMAPKs from healthy and GPA-infested peach leaves by whole-transcriptome sequencing and predicted the differentially expressed circRNAs (DECs) after GPA infestation. PCR and Sanger sequencing confirmed the presence of six DECs in peach samples. Besides, RNA sequencing analysis detected 13 DECs, including 5 upregulated and 8 downregulated ones, in peach in response to the GPA attack. Gene ontology (GO) enrichment analysis indicated that specific DECs play crucial roles in the MAPK signaling pathway, and qRT-PCR revealed that GPA infestation altered the expression patterns of PpMAPKs. Finally, five circRNAs, three microRNA (miRNAs), and two MAPK target genes were identified to interact as a network and perform critical roles in modulating the MAPK pathway in the peach during GPA infestation.

Exploring the Phytochemistry, Signaling Pathways, and Mechanisms of Action of Tanacetum parthenium (L.) Sch.Bip.: A Comprehensive Literature Review.

The traditional use of Tanacetum parthenium (L.) Sch.Bip., commonly known as feverfew, extends across various medical conditions, notably those associated with pain and inflammation. In alignment with the growing trend towards developing medications that target specific signaling pathways for enhanced efficacy and reduced side effects, extensive research has been conducted to investigate and validate the pharmacological effects of feverfew. Among its bioactive compounds, parthenolide stands out as the most potent, categorized as a germacranolide-type sesquiterpene lactone, and has been extensively studied in multiple investigations. Significantly, the anti-inflammatory properties of feverfew have been primarily attributed to its capacity to inhibit nuclear factor-kappa B (NF-κB), resulting in a reduction in pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α). Furthermore, the anticancer properties of feverfew have been associated with the modulation of Mitogen-Activated Protein Kinase (MAPK) and NF-κB signaling pathways. This study further delves into the neuroprotective potential of feverfew, specifically in the management of conditions such as migraine headaches, epilepsy, and neuropathic pain through various mechanisms. The core objective of this study is to elucidate the phytochemical composition of feverfew, with a particular emphasis on understanding the molecular mechanisms and examining the signaling pathways that contribute to its pharmacological and therapeutic effects. Additionally, the safety, toxicity, and potential adverse effects of feverfew are comprehensively evaluated, with an overarching goal of providing valuable insights into the plant's potential for targeted and effective treatments.

The syntaxin-binding protein STXBP5 regulates progerin expression.

Hutchinson-Gilfor progeria syndrome (HGPS) is caused by a mutation in Lamin A resulting in the production of a protein called progerin. The accumulation of progerin induces inflammation, cellular senescence and activation of the P53 pathway. In this study, through public dataset analysis, we identified Syntaxin Binding Protein 5 (STXBP5) as an influencing factor of progerin expression. STXBP5 overexpression accelerated the onset of senescence, while STXBP5 deletion suppressed progerin expression, delayed senility, and decreased the expression of senescence-related factors. STXBP5 and progerin have synergistic effects and a protein-protein interaction. Through bioinformatics analysis, we found that STXBP5 affects ageing-related signalling pathways such as the mitogen-activated protein kinase (MAPK) pathway, the hippo pathway and the interleukin 17 (IL17) signalling pathway in progerin-expressing cells. In addition, STXBP5 overexpression induced changes in transposable elements (TEs), such as the human endogenous retrovirus H internal coding sequence (HERVH-int) changes. Our protein coimmunoprecipitation (Co-IP) results indicated that STXBP5 bound directly to progerin. Therefore, decreasing STXBP5 expression is a potential new therapeutic strategy for treating ageing-related phenotypes in patients with HGPS.

Conserved perception of host and non-host signals via the a-pheromone receptor Ste3 in Colletotrichum graminicola.

Understanding the interactions between fungal plant pathogens and host roots is crucial for developing effective disease management strategies. This study investigates the molecular mechanisms underpinning the chemotropic responses of the maize anthracnose fungus Colletotrichum graminicola to maize root exudates. Combining the generation of a deletion mutant with monitoring of disease symptom development and detailed analysis of chemotropic growth using a 3D-printed device, we identify the 7-transmembrane G-protein coupled receptor (GPCR) CgSte3 as a key player in sensing both plant-derived class III peroxidases and diterpenoids. Activation of CgSte3 initiates signaling through CgSo, a homolog to the Cell Wall Integrity Mitogen-Activated Protein Kinase (CWI MAPK) pathway scaffold protein identified in other filamentous fungi, facilitating the pathogen's growth towards plant defense molecules. The NADPH oxidase CgNox2 is crucial for peroxidase sensing but not for diterpenoid detection. These findings reveal that CgSte3 and CWI MAPK pathways are central to C. graminicola's ability to hijack plant defense signals, highlighting potential targets for controlling maize anthracnose.

Schisandrin A Alleviates Inflammation and Oxidative Stress in Aβ25-35-Induced Alzheimer's Disease in Vitro Model.

Schisandra extract has therapeutic and preventive effects on Alzheimer's disease (AD). Therefore, this study evaluated the anti-AD potential of Schisandrin A (SCH A) using an in vitro cell model. SH-SY5Y and SK-N-SH cells were treated with 20 µM amyloid β-protein (Aβ)25-35. The Aβ25-35-induced cells were then exposed to different concentrations of SCH A (1, 5, 10, 15 µg/mL). Moreover, to further explore the role of the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) pathway in the anti-AD effects of SHC A, SH-SY5Y cells were treated with SCH A following incubation with ERK activator LM22B-10. The impact of SCH A on cell viability and apoptosis was evaluated using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry. Furthermore, the oxidative stress markers and inflammatory cytokine levels were also assessed. The reactive oxygen species (ROS) levels were examined using 2',7'-Dichlorodihydrofluorescein Diacetate (DCFH-DA) method. Finally, Western blot analysis was employed to evaluate the phospho-ERK1/2 (p-ERK1/2) and ERK1/2. We observed that SCH A treatment (5, 10, 15 µg/mL) substantially increased the cell viability (p < 0.05), and reduced the apoptosis rate (10 and 15 µg/mL) in SH-SY5Y and SK-N-SH cells (p < 0.05). SCH A significantly ameliorated oxidative stress and reduced inflammatory cytokine levels in Aβ25-35-induced cells (p < 0.05). Furthermore, SCH A up-regulated the p-ERK1/2 to ERK1/2 ratio in Aβ25-35-induced cells. However, LM22B-10 treatment was found to exacerbate this effect of SCH A (p < 0.05). SCH A reduces the Aβ25-35-induced inflammatory response and oxidative stress in SH-SY5Y and SK-N-SH cells, and the activation of the ERK/MAPK signaling pathway was related to its potential mechanism.

Molecular Mechanism of 5,6-Dihydroxyflavone in Suppressing LPS-Induced Inflammation and Oxidative Stress.

5,6-dihydroxyflavone (5,6-DHF), a flavonoid that possesses potential anti-inflammatory and antioxidant activities owing to its special catechol motif on the A ring. However, its function and mechanism of action against inflammation and cellular oxidative stress have not been elucidated. In the current study, 5,6-DHF was observed inhibiting lipopolysaccharide (LPS)-induced nitric oxide (NO) and cytoplasmic reactive oxygen species (ROS) production with the IC50 of 11.55 ± 0.64 μM and 0.8310 ± 0.633 μM in murine macrophages, respectively. Meanwhile, 5,6-DHF suppressed the overexpression of pro-inflammatory mediators such as proteins and cytokines and eradicated the accumulation of mitochondrial ROS (mtROS). The blockage of the activation of cell surface toll-like receptor 4 (TLR4), impediment of the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 from the mitogen-activated protein kinases (MAPK) pathway, Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) from the JAK-STAT pathway, and p65 from nuclear factor-κB (NF-κB) pathways were involved in the process of 5,6-DHF suppressing inflammation. Furthermore, 5,6-DHF acted as a cellular ROS scavenger and heme-oxygenase 1 (HO-1) inducer in relieving cellular oxidative stress. Importantly, 5,6-DHF exerted more potent anti-inflammatory activity than its close structural relatives, such as baicalein and chrysin. Overall, our findings pave the road for further research on 5,6-DHF in animal models.

Immunostimulatory Activity of a Mixture of Platycodon grandiflorum, Pyrus serotine, Chaenomeles sinensis, and Raphanus sativus in RAW264.7 Macrophages.

In this study, a mixture of Platycodon grandiflorum, Pyrus serotina, Chaenomeles sinensis, and Raphanus sativus (PPCRE) was investigated for their immuno-enhancing effects, as well as the molecular mechanism of PPCRE in RAW264.7 cells. PPCRE dramatically increased nitric oxide (NO) and prostaglandin E2 (PGE2) generation depending on the concentration while exhibiting no cytotoxicity. PPCRE markedly upregulated the mRNA and protein expression of immune-related cytotoxic factors such as cyclooxygenase (COX)-1, COX-2, and inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha (TNF-α), as well as the mRNA level of IL-4. PPCRE increased the mitogen-activated protein kinase (MAPK) signaling pathway by upregulating the phosphorylation of extracellular signal-regulated kinase (ERK), stress-activated protein kinase/Jun N-terminal-kinase (SAPK/JNK), and p38. Furthermore, PPCRE considerably activated the nuclear factor kappa B (NF-κB) signaling pathway by increasing phosphorylation of NF-κB-p65. PPCRE-stimulated RAW264.7 cells increased macrophage phagocytic capacity. In conclusion, our study found that PPCRE improved immune function by modulating inflammatory mediators and regulating the MAPK and NF-κB pathway of signaling in macrophages.

The Impact of Hydrogen Sulfide in the Paraventricular Nucleus on the MAPK Pathway in High Salt-Induced Hypertension.

The hypothalamic paraventricular nucleus (PVN) plays a central role in regulating cardiovascular activity and blood pressure. We administered hydroxylamine hydrochloride (HA), a cystathionine-β-synthase inhibitor, into the PVN to suppress endogenous hydrogen sulfide and investigate its effects on the mitogen-activated protein kinase (MAPK) pathway in high salt (HS)-induced hypertension. We randomly divided 40 male Dahl salt-sensitive rats into 4 groups: the normal salt (NS) + PVN vehicle group, the NS + PVN HA group, the HS + PVN vehicle group, and the HS + PVN HA group, with 10 rats in each group. The rats in the NS groups were fed a NS diet containing 0.3% NaCl, while the HS groups were fed a HS diet containing 8% NaCl. The mean arterial pressure was calculated after noninvasive measurement using an automatic sphygmomanometer to occlude the tail cuff once a week. HA or vehicle was infused into the bilateral PVN using Alzet osmotic mini pumps for 6 weeks after the hypertension model was successfully established. We measured the levels of H 2 S in the PVN and plasma norepinephrine using enzyme linked immunosorbent assay. In addition, we assessed the parameters of the MAPK pathway, inflammation, and oxidative stress through western blotting, immunohistochemical analysis, or real-time polymerase chain reaction. In this study, we discovered that decreased levels of endogenous hydrogen sulfide in the PVN contributed to the onset of HS-induced hypertension. This was linked to the activation of the MAPK signaling pathway, proinflammatory cytokines, and oxidative stress in the PVN, as well as the activation of the sympathetic nervous system.

Implications of trinodal inhibitions and drug repurposing in MAPK pathway: A putative remedy for breast cancer

Breast cancer has been one of the supreme causes of cancer-related deaths among women worldwide. To make the case even more compounded, due to innate or acquired causes, cancer cells often develop resistance against the available chemotherapy or monotargeted treatments. This resistance is concomitant with increased activation of the MAPK (mitogen-activated protein kinase) signaling pathway. This study simultaneously targets three imperative intermediates in this pathway using molecular docking and real-time simulation. Docking was performed via the integrated AutoDock Vina 1.1.2 & 1.2.5 of the PyRx software, while the Discovery Studio (BIOVIA) v24.1.0.23298 was utilized to conduct the simulation. The aim is to investigate the therapeutic prospects of known potential inhibitors of the targeted intermediates and repurposable drugs to comprehend the effectiveness of targeting these trinodes simultaneously. The target points were deemed to be PDPK1 (3-phosphoinositide-dependent protein kinase 1), ERK1/2 (extracellular signal-related protein kinases 1/2), and mTOR (mammalian target of Rapamycin). Our study reveals that out of the candidate inhibitors chosen for each node, MP7 exhibited the most superior binding affinities for all three: −10.918 kcal/mol for PDPK1, −10.224 kcal/mol for ERK1, −10.134 kcal/mol for ERK2, and −9.2 kcal/mol for mTOR (via AutoDock Vina 1, .2.5). Some scores with MP7 were often higher than the available single-targeted drugs for different nodes in the MAPK pathway. Additionally, a total of 1867 repurposed analgesic, antibiotic, and antiparasitic drugs, including Zavegepant (−13.399 kcal/mol for PDPK1), Adozelesin (−11.74 kcal/mol for mTOR) and Modoflaner (−11.29 kcal/mol for PDPK1), showed promising binding energetics while targeting our triad points than other compounds used. This approach prompts for mitigating not only breast cancer but other elusive diseases as well, with state-of-the-art multitargeted therapies coupled with bioinformatic strategies.

Herbal medicine Ninjinyoeito inhibits RANKL-induced osteoclast differentiation and bone resorption activity by regulating NF-κB and MAPK pathway

ObjectivesOsteoporosis is a systemic bone metabolism disorder characterized by decreased bone mass and strength. Osteoclasts (OCs) are giant multinucleated cells that regulate bone homeostasis by degrading bone matrix. Excessive OC differentiation and activity can lead to serious bone metabolic disorders including osteoporosis. Current treatments, including antiresorptive drugs, exert considerable adverse effects, including jaw osteonecrosis. Herbal medicines, such as Ninjinyoeito (NYT), may also offer efficacy, but with fewer adverse effects. In this study, we investigated NYT's effects on osteoclastogenesis. MethodsTartrate-resistant acid phosphatase (TRAP) staining and bone resorption assays were performed to examine NYT's effects on OC differentiation and function. OC-related gene expression at mRNA and protein levels was investigated to confirm NYT's inhibitory action against osteoclastogenesis. We also demonstrated involvement of signaling pathways mediated by IκBα and mitogen-activated protein kinases (MAPK) [extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38] and showed nuclear translocation of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) and nuclear factor kappa B (NF-κB) p65 during osteoclastogenesis. ResultsTRAP staining and bone resorption assays confirmed that NYT significantly inhibited OC differentiation and function. Western blot and RT-PCR results showed that NYT ameliorated osteoclastogenesis by suppressing mRNA and protein level expression of OC-related genes. Moreover, blots and immunocytochemistry (ICC) data clarified that NYT abrogates signaling pathways mediated by IκBα and MAPK (ERK, JNK, p38), and demonstrated nuclear translocation of NFATc1 and NF-κB p65 during OC differentiation. ConclusionsThese findings suggest NYT is an alternative therapeutic candidate for treating osteoporosis.

Oral administration of PIISVYWK and FSVVPSPK peptides attenuates obesity, oxidative stress, and inflammation in high fat diet-induced obese mice

The bioactive peptides PIISVYWK (P1) and FSVVPSPK (P2), derived from the blue mussel Mytilus edulis, exhibit significant benefits in combating obesity, oxidative stress, and inflammation. This study demonstrates that these peptides inhibit the differentiation of bone marrow-derived mesenchymal stem cells (BMMSCs) into adipocytes by downregulating the adipogenic transcription factors peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP-1). Furthermore, P1 and P2 reduce lipogenesis and enhance lipolysis through the activation of AMP-activated protein kinase (AMPK) and hormone-sensitive lipase (HSL). These peptides also decrease intracellular reactive oxygen species (ROS) generation during adipogenesis and inhibit the mitogen-activated protein kinase (MAPK) pathway, thereby reducing inflammation. The involvement of heme oxygenase-1 (HO-1) in this mechanism is confirmed by the reversal of these effects upon HO-1 inhibition. In vivo, oral administration of P1 and P2 in high-fat diet (HFD) obese mice prevents weight gain, reduces adipose tissue accumulation, lowers adipogenic and lipogenic biomarkers, improves serum cholesterol levels, enhances lipolysis, and decreases pro-inflammatory cytokine production. These findings suggest that P1 and P2 peptides may effectively prevent obesity and related metabolic disorders by activating the HO-1/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway.