Green tea extract suppresses airway inflammation via oxidative stress-driven MAPKs/MMP-9 signaling in asthmatic mice and human airway epithelial cells.

Introduction: The anti-inflammatory effect of green tea extract (GTE) has been confirmed in asthmatic mice, however, the pharmacological mechanism is not fully elucidated. Methods: To investigate the therapeutic efficacy of GTE in asthma and identify specific pathways, murine model of allergic asthma was established by ovalbumin (OVA) sensitization and the challenge for 4 weeks, with oral treatment using GTE and dexamethasone (DEX). Inflammatory cell counts, cytokines, OVA-specific IgE, airway hyperreactivity, and antioxidant markers in the lung were evaluated. Also, pulmonary histopathological analysis and western blotting were performed. In vitro, we established the model by stimulating the human airway epithelial cell line NCI-H292 using lipopolysaccharide, and treating with GTE and mitogen-activated protein kinases (MAPKs) inhibitors. Results: The GTE100 and GTE400 groups showed a decrease in airway hyperresponsiveness and the number of inflammatory cells in the bronchoalveolar lavage fluid (BALF) compared to the OVA group. GTE treatment also reduced interleukin (IL)-13, IL-5, and IL-4 levels in the BALF, and OVA-specific immunoglobulin E levels in the serum compared to those in the OVA group. GTE treatment decreased OVA-induced mucus secretion and airway inflammation. In addition, GTE suppressed the oxidative stress, and phosphorylation of MAPKs, which generally occurs after exposure to OVA. GTE administration also reduced matrix metalloproteinase-9 activity and protein levels. Conclusion: GTE effectively inhibited asthmatic respiratory inflammation and mucus hyperproduction induced by OVA inhalation. These results suggest that GTE has the potential to be used for the treatment of asthma.

Long-term 4-nonylphenol exposure drives cervical cell malignancy through MAPK-mediated ferroptosis inhibition.

4-NP (4-nonylphenol), a prevalent environmental endocrine disruptor with estrogenic properties, is commonly detected in drinking water and food sources. It poses a significant risk of endocrine disruption, thereby influencing the onset and progression of diverse diseases, including tumorigenesis. However, its specific impact on cervical cancer remains to be fully elucidated. Our study focused on the biological effects of sustained exposure to low-dose 4-NP on human normal cervical epithelial cells (HcerEpic). After a continuous 30-week exposure to 4-NP, the treated cells exhibited a significant malignant transformation, whereas the solvent control group showed limited malignant phenotypes. Subsequent analyses of the metabolomic profiles of the transformed cells unveiled marked irregularities in glutathione metabolism and unsaturated fatty acid metabolism. Analyses of transcriptomic profiles revealed significant activation of the MAPK signaling pathway and suppression of ferroptosis processes in these cells. Furthermore, the expression of MT2A was significantly upregulated following 4-NP exposure. Knockdown of MT2A restored the aberrant activation of the MAPK signaling pathway, elevated antioxidant capacity, ferroptosis inhibition, and ultimately the development of malignant phenotypes that induced by 4-NP in the transformed cells. Mechanistically, MT2A increased cellular antioxidant capabilities and facilitated the removal of toxic iron ions by enhancing the phosphorylation of ERK1/2 and JNK MAPK pathways. The administration of activators and inhibitors of the MAPK pathway confirmed that the MAPK pathway mediated the 4-NP-induced suppression of ferroptosis and, ultimately, the malignant transformation of cervical epithelial cells. Overall, our findings elucidated a dynamic molecular transformation induced by prolonged exposure to 4-NP, and delineated comprehensive biological perspectives underlying 4-NP-induced cervical carcinogenesis. This offers novel theoretical underpinnings for the assessment of the carcinogenic risks associated with 4-NP.

Imeglimin attenuates NLRP3 inflammasome activation by restoring mitochondrial functions in macrophages.

Imeglimin is a novel oral antidiabetic drug for treating type 2 diabetes. However, the effect of imeglimin on NLRP3 inflammasome activation has not been investigated yet. Here, we aimed to investigate whether imeglimin reduces LPS-induced NLRP3 inflammasome activation in THP-1 macrophages and examine the associated underlying mechanisms. We analyzed the mRNA and protein expression levels of NLRP3 inflammasome components and IL-1ß secretion. Additionally, reactive oxygen species (ROS) generation, mitochondrial membrane potential, and mitochondrial permeability transition pore (mPTP) opening were measured by flow cytometry. Imeglimin inhibited NLRP3 inflammasome-mediated IL-1ß production in LPS-stimulated THP-1-derived macrophages. In addition, imeglimin reduced LPS-induced mitochondrial ROS production and mitogen-activated protein kinase phosphorylation. Furthermore, imeglimin restored the mitochondrial function by modulating mitochondrial membrane depolarization and mPTP opening. We demonstrated for the first time that imeglimin reduces LPS-induced NLRP3 inflammasome activation by inhibiting mPTP opening in THP-1 macrophages. These results suggest that imeglimin could be a promising new anti-inflammatory agent for treating diabetic complications.

A Method to Conditionally Measure Target Engagement at Intracellular RAS and RAF Complexes.

Dysfunction of the RAS/mitogen-activated protein kinase (MAPK) pathway is a common driver of human cancers. As such, both the master regulator of the pathway, RAS, and its proximal kinase effectors, RAFs, have been of interest as drug targets for decades. Importantly, signaling within the RAS/MAPK pathway is highly coordinated due to the formation of a higher-order complex called the RAS/RAF signalosome, which may minimally contain dimers of both RAS and RAF protomers. In the disease state, RAS and RAF assemble in homo- and/or heterodimeric forms. Traditionally, drug development campaigns for both RAS and RAF have utilized biochemical assays of purified recombinant protein. As these assays do not query the RAS or RAF proteins in their full-length and complexed forms in cells, potency results collected using these assays have often failed to correlate with inhibition of the MAPK pathway. To more accurately quantify engagement at this signaling components, we present a bioluminescence resonance energy transfer (BRET)-based method to conditionally measure target engagement at individual protomers within the RAS/RAF signalosome in live cells.

Deregulated JNK signaling enhances apoptosis during hyperthermia.

PURPOSE: c-Jun N-terminal kinases (JNKs) comprise a subfamily of mitogen-activated protein kinases (MAPKs). The JNK group is known to be activated by a variety of stimuli. However, the molecular mechanism underlying heat-induced JNK activation is largely unknown. The aim of this study was to clarify how JNK activity is stimulated by heat. METHODS AND MATERIALS: The expression levels of various MAPK members in HeLa cells, with or without hyperthermia treatment, were evaluated via western blotting. The kinase activity of MAPK members was assessed through in vitro kinase assays. Cell death was assessed in the absence or presence of siRNAs targeting MAPK-related members. RESULTS: Hyperthermia decreased the levels of MAP3Ks, such as ASK1 and MLK3 which are JNK kinase kinase members, but not those of the downstream MAP2K/SEK1 and MAPK/JNK. Despite the reduced or transient phosphorylation of ASK1, MLK3, or SEK1, downstream JNK was phosphorylated in a temperature-dependent manner. In vitro kinase assays demonstrated that heat did not directly stimulate SEK1 or JNK. However, the expression levels of DUSP16, a JNK phosphatase, were decreased upon hyperthermia treatment. DUSP16 knockdown enhanced the heat-induced activation of ASK1-SEK1-JNK pathway and apoptosis. CONCLUSION: JNK was activated in a temperature-dependent manner despite reduced or transient phosphorylation of the upstream MAP3K and MAP2K. Hyperthermia-induced degradation of DUSP16 may induce activation of the ASK1-SEK1-JNK pathway and subsequent apoptosis.

C-type lectin 4 of Toxocara canis activates NF-ĸB and MAPK pathways by modulating NOD1/2 and RIP2 in murine macrophages in vitro.

Toxocara canis is a parasitic zoonose that is distributed worldwide and is one of the two pathogens causing toxocariasis. After infection, it causes serious public health and safety problems, which pose significant veterinary and medical challenges. To better understand the regulatory effects of T. canis infection on the host immune cells, murine macrophages (RAW264.7) were incubated with recombinant T. canis C-type lectin 4 (rTc-CTL-4) protein in vitro. The quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to analyze the nucleotide-binding oligomerization domain-containing protein 1/2 (NOD1/2), receptor-interacting protein 2 (RIP2), nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB), and mitogen-activated protein kinase (MAPK) on mRNA level and protein expression level in macrophages. Our results indicated that 10 µg/mL rTc-CTL-4 protein could modulate the expression of NOD1, NOD2, and RIP2 at both the transcriptional and translational levels. The protein translation levels of NF-κB, P-p65, p38, and P-p38 in macrophages were also modulated by rTc-CTL-4 protein. Macrophages were co-incubated with rTc-CTL-4 protein after siRNA silencing of NOD1, NOD2, and RIP2. The expression levels of NF-κB, P-p65, p38, and P-p38 were significantly changed compared with the negative control groups (Neg. Ctrl.). Taken together, rTc-CTL-4 protein seemed to act on NOD1/2-RIP2-NF-κB and MAPK signaling pathways in macrophages and might activate MAPK and NF-κB signaling pathways by regulating NOD1, NOD2, and RIP2. The insights from the above studies could contribute to our understanding of immune recognition and regulatory mechanisms of T. canis infection in the host animals.

Piper longum L. ameliorates gout through the MAPK/PI3K-AKT pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Gout, a painful joint disease with a prevalence ranging from 0.86% to 2.2% in China over the past decade. Traditional medicine has long utilized the medicinal and edible Piper longum L. (PL) fruit spikes for treating gout and other joint conditions like rheumatoid arthritis. However, the exact mechanisms behind its effectiveness remain unclear. AIM OF THE STUDY: This study aimed to investigate the potential of alcoholic extracts from PL fruit spikes as a safe and effective treatment for gout. We used a combined network pharmacology and experimental validation approach to evaluate the mechanisms behind the anti-gout properties of PL. MATERIALS AND METHODS: UPLC-Q/TOF-MS analysis determined the major components of PL. Subsequently, network pharmacology analysis predicted potential molecular targets and related signaling pathways for the anti-gout activity of PL. Molecular docking simulations further explored the interactions between PL compounds and proteins and characterized the properties of potential bioactive secondary metabolites. Mouse models of air pouch inflammation and hyperuricemia were further established, and the anti-gout mechanism of PL was confirmed by examining the expression of proteins related to the MAPK and PI3K-AKT pathways in the tissue. RESULTS: Our analysis revealed 220 bioactive secondary metabolites within PL extracts. Network pharmacology and molecular docking results indicated that these metabolites primarily combat gout by modulating the PI3K-AKT and MAPK signaling pathways. In vivo experiments have also proven that PL at a dose of 100 mg/kg can optimally reduce acute inflammation of gout and kidney damage caused by high uric acid. The anti-gout mechanism involves the PI3K-AKT/MAPK signaling pathway and its downstream NF-κB pathway. CONCLUSION: This study provides compelling evidence for PL's therapeutic potential in gout management by modulating key inflammatory pathways. The findings offer a strong foundation for future clinical exploration of PL as a gout treatment option.

Fus3 Interacts with Gal83, Revealing the MAPK Crosstalk to Snf1/AMPK to Regulate Secondary Metabolic Substrates in Aspergillus flavus.

Aflatoxins (AFs), highly carcinogenic natural products, are produced by the secondary metabolism of fungi such as Aspergillus flavus. Essential for the fungi to respond to environmental changes and aflatoxin synthesis, the pheromone mitogen-activated protein kinase (MAPK) is a potential regulator of aflatoxin biosynthesis. However, the mechanism by which pheromone MAPK regulates aflatoxin biosynthesis is not clear. Here, we showed Gal83, a new target of Fus3, and identified the pheromone Fus3-MAPK signaling pathway as a regulator of the Snf1/AMPK energy-sensing pathway modulating aflatoxins synthesis substrates. The screening for Fus3 target proteins identified the ß subunit of Snf1/AMPK complexes using tandem affinity purification and multiomics. This subunit physically interacted with Fus3 both in vivo and in vitro and received phosphorylation from Fus3. Although the transcript levels of aflatoxin synthesis genes were not noticeably downregulated in both gal83 and fus3 deletion mutant strains, the levels of aflatoxin B1 and its synthesis substrates and gene expression levels of primary metabolizing enzymes were significantly reduced. This suggests that both the Fus3-MAPK and Snf1/AMPK pathways respond to energy signals. In conclusion, all the evidence unlocks a novel pathway of Fus3-MAPK to regulate AFs synthesis substrates by cross-talking with the Snf1/AMPK complexes.

Combined KRAS-MAPK pathway inhibitors and HER2-directed drug conjugate is efficacious in pancreatic cancer.

Targeting the mitogen-activated protein kinase (MAPK) cascade in pancreatic ductal adenocarcinoma (PDAC) remains clinically unsuccessful. We aim to develop a MAPK inhibitor-based therapeutic combination with strong preclinical efficacy. Utilizing a reverse-phase protein array, we observe rapid phospho-activation of human epidermal growth factor receptor 2 (HER2) in PDAC cells upon pharmacological MAPK inhibition. Mechanistically, MAPK inhibitors lead to swift proteasomal degradation of dual-specificity phosphatase 6 (DUSP6). The carboxy terminus of HER2, containing a TEY motif also present in extracellular signal-regulated kinase 1/2 (ERK1/2), facilitates binding with DUSP6, enhancing its phosphatase activity to dephosphorylate HER2. In the presence of MAPK inhibitors, DUSP6 dissociates from the protective effect of the RING E3 ligase tripartite motif containing 21, resulting in its degradation. In PDAC patient-derived xenograft (PDX) models, combining ERK and HER inhibitors slows tumour growth and requires cytotoxic chemotherapy to achieve tumour regression. Alternatively, MAPK inhibitors with trastuzumab deruxtecan, an anti-HER2 antibody conjugated with cytotoxic chemotherapy, lead to sustained tumour regression in most tested PDXs without causing noticeable toxicity. Additionally, KRAS inhibitors also activate HER2, supporting testing the combination of KRAS inhibitors and trastuzumab deruxtecan in PDAC. This study identifies a rational and promising therapeutic combination for clinical testing in PDAC patients.

Cancer cell genetics shaping of the tumor microenvironment reveals myeloid cell-centric exploitable vulnerabilities in hepatocellular carcinoma.

Myeloid cells are abundant and plastic immune cell subsets in the liver, to which pro-tumorigenic, inflammatory and immunosuppressive roles have been assigned in the course of tumorigenesis. Yet several aspects underlying their dynamic alterations in hepatocellular carcinoma (HCC) progression remain elusive, including the impact of distinct genetic mutations in shaping a cancer-permissive tumor microenvironment (TME). Here, in newly generated, clinically-relevant somatic female HCC mouse models, we identify cancer genetics' specific and stage-dependent alterations of the liver TME associated with distinct histopathological and malignant HCC features. Mitogen-activated protein kinase (MAPK)-activated, NrasG12D-driven tumors exhibit a mixed phenotype of prominent inflammation and immunosuppression in a T cell-excluded TME. Mechanistically, we report a NrasG12D cancer cell-driven, MEK-ERK1/2-SP1-dependent GM-CSF secretion enabling the accumulation of immunosuppressive and proinflammatory monocyte-derived Ly6Clow cells. GM-CSF blockade curbs the accumulation of these cells, reduces inflammation, induces cancer cell death and prolongs animal survival. Furthermore, GM-CSF neutralization synergizes with a vascular endothelial growth factor (VEGF) inhibitor to restrain HCC outgrowth. These findings underscore the profound alterations of the myeloid TME consequential to MAPK pathway activation intensity and the potential of GM-CSF inhibition as a myeloid-centric therapy tailored to subsets of HCC patients.

YBX-1 alleviates sepsis-stimulated lung epithelial cell injury.

OBJECTIVE: To explore the role of Y-box binding protein 1 (YBX-1) in the lipopolysaccharide (LPS)-stimulated inflammation and oxidative stress of BEAS-2B cell line and clarify the underlying mechanism. METHODS: LPS-stimulated BEAS-2B cells were used as a cell model of sepsis-stimulated acute lung injury (ALI). Immunoblot and quantitative polymerase chain reaction assays were used to detect the expression of YBX-1 in LPS-stimulated BEAS-2B cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide, TdT-mediated dUTP nick end labeling, and immunoblot assays were conducted to determine the effects of YBX-1 on cell survival. JC-1 staining and adenosine triphosphate production were used to detect the effects of YBX-1 on mitochondrial function. Immunostaining and enzyme-linked immunosorbent serologic assay were performed to examine the effects of YBX-1 on the inflammation and oxidative stress of cells. Immunoblot assay was conducted to confirm the mechanism. RESULTS: YBX-1 was lowly expressed in LPS-stimulated BEAS-2B cells and enhanced the survival of LPS-stimulated lung epithelial cells. In addition, YBX-1 improved mitochondrial function of LPS-stimulated BEAS-2B cells. YBX-1 inhibited the inflammation and oxidative stress of LPS-stimulated BEAS-2B cells. Mechanically, YBX-1 inhibited mitogen-activated protein kinase (MAPK) axis, thereby alleviating sepsis-stimulated ALI. CONCLUSION: YBX-1 alleviated inflammation and oxidative stress of LPS-stimulated BEAS-2B cells via MAPK axis.

Extracellular vesicles derived from human foreskin cells (hFS-Exo) accelerate cell migration and angiogenesis through MAPK pathway: an in vitro study.

BACKGROUND: Wound healing is one of the important processes in the body. Attempts to create new drugs are of interest due to the side effects of natural and chemical wound healing compounds. To overcome this obstacle, stem cells have been used as healing agents. However, both difficulties in collection and risks such as rejection and teratoma in the recipient body have limited the use of stem cells, directly. Since the potential content of the stem cells can be transferred to the recipient cells by vesicles, small extracellular vesicles have recently become prominent agents. METHODS AND RESULTS: The wound-healing effect of extracellular vesicles derived from foreskin cells was investigated in both keratinocyte and endothelial cells. Migration assay, RT-PCR, Col1a1 ELISA and Western Blot experiments were utilized to reveal healing effect of EVs and its possible molecular pathways. EV-treated groups exhibited more proliferative, invasive, and migrative characteristics. When comparing to the control group, new vessel formation was induced in EV groups. An increase in gene levels of growth factors related to wound healing and change in the mitogen-activated protein kinase (MAPK) signaling pathway proteins in EV-treated groups were determined. Possible molecular mechanisms underlying cell movements were associated with the MAPK pathway. It was found that human foreskin cell EVs (hFS-Exo) may have a potential to heal wounds in a short period of time by triggering the MAPK pathway. CONCLUSIONS: hFS-Exo could be a new promising wound healing agent in the future.

Identification of mitogen-activated protein kinases substrates in Arabidopsis using kinase client assay.

Mitogen-activated protein kinase (MPK) cascades are essential signal transduction components that control a variety of cellular responses in all eukaryotes. MPKs convert extracellular stimuli into cellular responses by the phosphorylation of downstream substrates. Although MPK cascades are predicted to be very complex, only limited numbers of MPK substrates have been identified in plants. Here, we used the kinase client (KiC) assay to identify novel substrates of MPK3 and MPK6. Recombinant MPK3 or MPK6 were tested against a large synthetic peptide library representing in vivo phosphorylation sites, and phosphorylated peptides were identified by high-resolution tandem mass spectrometry. From this screen, we identified 23 and 21 putative client peptides of MPK3 and MPK6, respectively. To verify the phosphorylation of putative client peptides, we performed in vitro kinase assay with recombinant fusion proteins of isolated client peptides. We found that 13 and 9 recombinant proteins were phosphorylated by MPK3 and MPK6. Among them, 11 proteins were proven to be the novel substrates of two MPKs. This study suggests that the KiC assay is a useful method to identify new substrates of MPKs.

Punicalagin promotes mincle-mediated phagocytosis of macrophages via the NF-κB and MAPK signaling pathways.

Punicalagin (PUN) is a polyphenol derived from the pomegranate peel. It has been reported to have many beneficial effects, including anti-inflammatory, anti-oxidant, and anti-proliferation. However, the role of PUN in macrophage phagocytosis is currently unknown. In this study, we found that pre-treatment with PUN significantly enhanced phagocytosis by macrophages in a time- and dose-dependent manner in vitro. Moreover, KEGG enrichment analysis by RNA-sequencing showed that differentially expressed genes following PUN treatment were significantly enriched in phagocyte-related receptors, such as the C-type lectin receptor signaling pathway. Among the C-type lectin receptor family, Mincle (Clec4e) significantly increased at the mRNA and protein level after PUN treatment, as shown by qRT-PCR and western blotting. Small interfering RNA (siRNA) mediated knockdown of Mincle in macrophages resulted in down regulation of phagocytosis. Furthermore, western blotting showed that PUN treatment enhanced the phosphorylation of nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) in macrophages at the early stage. Mincle-mediated phagocytosis by PUN was inhibited by PDTC (a NF-κB inhibitor) and SB203580 (a p38 MAPK inhibitor). In addition, PUN pre-treatment enhanced phagocytosis by peritoneal and alveolar macrophages in vivo. After intraperitoneal injection of Escherichia coli (E.coli), the bacterial load of peritoneal lavage fluid and peripheral blood in PUN pre-treated mice decreased significantly. Similarly, the number of bacteria in the lung tissue significantly reduced after intranasal administration of Pseudomonas aeruginosa (PAO1). Taken together, our results reveal that PUN enhances bacterial clearance in mice by activating the NF-κB and MAPK pathways and upregulating C-type lectin receptor expression to enhance phagocytosis by macrophages.

Rhizoma Paridis saponins attenuate Gram-negative bacteria-induced inflammatory acne by binding to KEAP1 and modulating Nrf2 and MAPK pathways.

Acne vulgaris represents a chronic inflammatory condition, the pathogenesis of which is closely associated with the altered skin microbiome. Recent studies have implicated a profound role of Gram-negative bacteria in acne development, but there is a lack of antiacne agents targeting these bacteria. Polyphyllins are major components of Rhizoma Paridis with great anti-inflammatory potential. In this study, we aimed to evaluate the antiacne effects and the underlying mechanisms of PPH and a PPH-enriched Rhizoma Paridis extract (RPE) in treating the Gram-negative bacteria-induced acne. PPH and RPE treatments significantly suppressed the mRNA and protein expressions of interleukin (IL)-1ß and IL-6 in lipopolysaccharide (LPS)-induced RAW 264.7 and HaCaT cells, along with the intracellular reactive oxygen species (ROS) generation. Furthermore, PPH and RPE inhibited the nuclear translocation of nuclear factor kappa-B (NF-κB) P65 in LPS-induced RAW 264.7 cells. Based on molecular docking, PPH could bind to kelch-like ECH-associated protein 1 (KEAP1) protein. PPH and RPE treatments could activate nuclear factor erythroid 2-related factor 2 (NRF2) and upregulate haem oxygenase-1 (HO-1). Moreover, RPE suppressed the mitogen-activated protein kinase (MAPK) pathway. Therefore, PPH-enriched RPE showed anti-inflammatory and antioxidative effects in vitro, which is promising for alternative antiacne therapeutic.

Interferon inducible guanylate-binding protein 1 modulates the lipopolysaccharide-induced cytokines/chemokines and mitogen-activated protein kinases in macrophages.

Guanylate-binding proteins (GBPs) are a family of interferon (IFN)-inducible GTPases and play a pivotal role in the host immune response to microbial infections. These are upregulated in immune cells after recognizing the lipopolysaccharides (LPS), the major membrane component of Gram-negative bacteria. In the present study, the expression pattern of GBP1-7 was initially mapped in phorbol 12-myristate 13-acetate-differentiated human monocytes THP-1 and mouse macrophages RAW 264.7 cell lines stimulated with LPS. A time-dependent significant expression of GBP1-7 was observed in these cells. Moreover, among the various GBPs, GBP1 has emerged as a central player in regulating innate immunity and inflammation. Therefore, to study the specific role of GBP1 in LPS-induced inflammation, knockdown of the Gbp1 gene was carried out in both cells using small interfering RNA interference. Altered levels of different cytokines (interleukin [IL]-4, IL-10, IL-12ß, IFN-γ, tumor necrosis factor-α), inducible nitric oxide synthase, histocompatibility 2, class II antigen A, protein kinase R, and chemokines (chemokine (C-X-C motif) ligand 9 [CXCL9], CXCL10, and CXCL11) in GBP1 knockdown cells were reported compared to control cells. Interestingly, the extracellular-signal-regulated kinase 1/2 mitogen-activated protein (MAP) kinases and signal transducer and activator of transcription 1 (STAT1) transcription factor levels were considerably induced in knockdown cells compared to the control cells. However, no change in the level of phosphorylated nuclear factor-kB, c-Jun, and p38 transcription factors was observed in GBP1 knockdown cells compared to the control cells. This study concludes that GBP1 may alter the expression of cytokines, chemokines, and effector molecules mediated by MAP kinases and STAT1 transcription factors.

Macrophage SHP2 Deficiency Alleviates Diabetic Nephropathy via Suppression of MAPK/NF-κB- Dependent Inflammation.

Increasing evidence implicates chronic inflammation as the main pathological cause of diabetic nephropathy (DN). Exploration of key targets in the inflammatory pathway may provide new treatment options for DN. We aimed to investigate the role of Src homology 2-containing protein tyrosine phosphatase 2 (SHP2) in macrophages and its association with DN. The upregulated phosphorylation of SHP2 was detected in macrophages in both patients with diabetes and in a mouse model. Using macrophage-specific SHP2-knockout (SHP2-MKO) mice and SHP2fl/fl mice injected with streptozotocin (STZ), we showed that SHP2-MKO significantly attenuated renal dysfunction, collagen deposition, fibrosis, and inflammatory response in mice with STZ-induced diabetes. RNA-sequencing analysis using primary mouse peritoneal macrophages (MPMs) showed that SHP2 deletion mainly affected mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways as well as MAPK/NF-κB-dependent inflammatory cytokine release in MPMs. Further study indicated that SHP2-deficient macrophages failed to release cytokines that induce phenotypic transition and fibrosis in renal cells. Administration with a pharmacological SHP2 inhibitor, SHP099, remarkably protected kidneys in both type 1 and type 2 diabetic mice. In conclusion, these results identify macrophage SHP2 as a new accelerator of DN and suggest that SHP2 inhibition may be a therapeutic option for patients with DN.

Esketamine inhibits the c-Jun N-terminal kinase pathway in the spinal dorsal horn to relieve bone cancer pain in rats.

Cancer-induced bone pain (CIBP) is one of the most common and feared symptoms in patients with advanced tumors. The X-C motif chemokine ligand 12 (CXCL12) and the CXCR4 receptor have been associated with glial cell activation in bone cancer pain. Moreover, mitogen-activated protein kinases (MAPKs), as downstream CXCL12/CXCR4 signals, and c-Jun, as activator protein AP-1 components, contribute to the development of various types of pain. However, the specific CIBP mechanisms remain unknown. Esketamine is a non-selective N-methyl-d-aspartic acid receptor (NMDA) inhibitor commonly used as an analgesic in the clinic, but its analgesic mechanism in bone cancer pain remains unclear. We used a tumor cell implantation (TCI) model and explored that CXCL12/CXCR4, p-MAPKs, and p-c-Jun were stably up-regulated in the spinal cord. Immunofluorescence images showed activated microglia in the spinal cord on day 14 after TCI and co-expression of CXCL12/CXCR4, p-MAPKs (p-JNK, p-ERK, p-p38 MAPK), and p-c-Jun in microglia. Intrathecal injection of the CXCR4 inhibitor AMD3100 reduced JNK and c-Jun phosphorylations, and intrathecal injection of the JNK inhibitor SP600125 and esketamine also alleviated TCI-induced pain and reduced the expression of p-JNK and p-c-Jun in microglia. Overall, our data suggest that the CXCL12/CXCR4-JNK-c-Jun signaling pathway of microglia in the spinal cord mediates neuronal sensitization and pain hypersensitivity in cancer-induced bone pain and that esketamine exerts its analgesic effect by inhibiting the JNK-c-Jun pathway.

Betulinic acid attenuates T-2 toxin-induced lung injury by activating Nrf2 signaling pathway and inhibiting MAPK/NF-κB signaling pathway.

T-2 toxin, a type-A trichothecene mycotoxin, exists ubiquitously in mildewed foods and feeds. Betulinic acid (BA), a pentacyclic triterpenoid derived from plants, has the effect of relieving inflammation and oxidative stress. The purpose of this study was to investigate whether BA mitigates lung impairment caused by T-2 toxin and elucidate the underlying mechanism. The results indicated that T-2 toxin triggered the inflammatory cell infiltration, morphological alterations and cell apoptosis in the lungs. It is gratifying that BA ameliorated T-2 toxin-caused lung injury. The protein expression of nuclear factor erythrocyte 2-related factor 2 (Nrf2) pathway and the markers of antioxidative capability were improved in T-2 toxin induced lung injury by BA mediated protection. Simultaneously, BA supplementation could suppress T-2 toxin-induced mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB)-dependent inflammatory response and mitochondrial apoptotic pathway. Therefore, T-2 toxin gave rise to pulmonary toxicity, but these changes were moderated by BA administration through regulation of the Nrf2/MAPK/NF-κB pathway, which maybe offer a viable alternative for mitigating the lung impairments caused by the mycotoxin.

Sasanquasaponin from Camellia oleifera Abel Exerts an Anti-Inflammatory Effect in RAW 264.7 Cells via Inhibition of the NF-κB/MAPK Signaling Pathways.

Sasanquasaponin (SQS), a secondary metabolite that is derived from Camellia seeds, reportedly possesses notable biological properties. However, the anti-inflammatory effects of SQS and its underlying mechanisms remain poorly explored. Herein, we aimed to investigate the anti-inflammatory properties of SQS against lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 cells, focusing on the nuclear factor-κB (NF-κB) and MAPK signaling pathways. SQS was isolated using a deep eutectic solvent and D101 macroporous adsorption resin and analyzed using high-performance liquid chromatography. The viability of LPS-stimulated RAW264.7 was assessed using the CCK-8 assay. The presence of reactive oxygen species (ROS) was evaluated using 2',7'-dichlorofluorescein-diacetate. The expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6) were detected using reverse transcription-quantitative PCR and ELISA. Western blot was performed to analyze the protein expression of LPS-induced RAW264.7 cells. Herein, SQS exhibited anti-inflammatory activity: 30 µg/mL of SQS significantly reduced ROS generation, inhibited the LPS-induced expression of iNOS and COX-2, and attenuated the production of pro-inflammatory cytokines IL-1ß, IL-6, and TNF-α. The anti-inflammatory activity was potentially mediated by inhibiting the phosphorylation of IκBα and p65 in the NF-κB signaling pathway and the phosphorylation of ERK and JNK in the MAPK signaling pathway. Accordingly, SQS could inhibit inflammation in LPS-induced RAW264.7 cells by suppressing the NF-κB and MAPK signaling pathways. This study demonstrated the potential application of SQS as an anti-inflammatory agent.