Jun N-terminal Kinase Research Articles

Synergistic effect of Cortex Moutan and Poria in protecting myocardium against ischemic injury based on network pharmacology

Objective: To explore the potential mechanisms of Cortex Moutan-Poria synergistic effect in anti-myocardial ischemic injury based on network pharmacology. Methods: Active components from Cortex Moutan-Poria were identified using the TCMSP database, and their potential targets were predicted with the UniProt database. Gene targets related to myocardial ischemic injury were sourced from the TTD database. An analysis map linking the “herbal pair-active components-targets-disease” and corresponding protein networks were constructed using Cytoscape 3.10.1 software and the STRING platform, respectively. Enrichment analyses refer to the Kyoto Encyclopedia of the Genome (KEGG) pathway enrichment analyses and Gene Ontology (GO) databases for corresponding biological pathways and signalling pathway information for further exploration of the possible involvement of drug targets in downstream signalling. Results: A total of 17 active components of the Cortex Moutan-Poria herbal pair and 243 predicted targets were identified, among which 133 targets interacted with the active components in myocardial ischemic injury. Key genes associated with myocardial ischemic injury included B-cell lymphoma-2 (BCL-2), Jun N-terminal Kinase (JUN), Matrix Metallopeptidase 9 (MMP9), cysteine-dependent aspartate-specific proteases-3 (Caspase-3), Prostaglandin-Endoperoxide Synthase 2 (PTGS2), Interleukin-1β (IL-1β), Tumor Necrosis Factor (TNF), IL-6, Protein Kinase B (AKT1), and Stylonychia lemnae macronuclear development protein 6 (MDP6). Conclusion: The anti-myocardial ischemic injury effect of the Cortex Moutan-Poria combination is attributed to its multi-component, multi-target, and multi-pathway pharmacological properties. The pathways, core proteins, and major genes identified in this study for treating myocardial ischemic injury provide a theoretical foundation for subsequent experimental research.

An antibiotic that mediates immune destruction of senescent cancer cells

Drugs that eliminate senescent cells, senolytics, can be powerful when combined with prosenescence cancer therapies. Using a CRISPR/Cas9-based genetic screen, we identify here SLC25A23 as a vulnerability of senescent cancer cells. Suppressing SLC25A23 disrupts cellular calcium homeostasis, impairs oxidative phosphorylation, and interferes with redox signaling, leading to death of senescent cells. These effects can be replicated by salinomycin, a cation ionophore antibiotic. Salinomycin prompts a pyroptosis-apoptosis-necroptosis (PAN)optosis-like cell death in senescent cells, including apoptosis and two forms of immunogenic cell death: necroptosis and pyroptosis. Notably, we observed that salinomycin treatment or SLC25A23 suppression elevates reactive oxygen species, upregulating death receptor 5 via Jun N-terminal protein kinase (JNK) pathway activation. We show that a combination of a death receptor 5 (DR5) agonistic antibody and salinomycin is a robust senolytic cocktail. We provide evidence that this drug combination provokes a potent natural killer (NK) and CD8+ T cell-mediated immune destruction of senescent cancer cells, mediated by the pyroptotic cytokine interleukin 18 (IL18).

Effect of imatinib on lipopolysaccharide‑induced acute lung injury and endothelial dysfunction through the P38 MAPK and NF-κB signaling pathways in vivo and in vitro.

The primary purpose of this study was to demonstrate the preventive effects of imatinib (IMA) on lipopolysaccharide (LPS)-induced inflammation in a mouse model of acute lung injury (ALI) and human umbilical vascular endothelial cells. LPS stimulation for 24h induced ALI and cell inflammation. The pathological results of the lungs were evaluated using the wet/dry weight ratio, pulmonary vascular permeability measurements, and myeloperoxidase immunohistochemistry. The expression of pro-inflammatory mediators was analyzed using RT-PCR and enzyme-linked immunosorbent assay. Protein levels were analyzed using western blotting. The structure of cell junctions was detected using immunofluorescence. IMA improved LPS-induced pulmonary pathological damage and reduced the lung wet/dry weight ratio and myeloperoxidase expression in the lung tissue. IMA decreased bronchoalveolar lavage fluid inflammatory cell count and the release of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and monocyte chemotactic protein 1 (MCP-1) in the blood. Pretreatment of human umbilical vascular endothelial cells with IMA significantly attenuated LPS-induced actin stress fiber formation and vascular endothelial-cadherin disruption. In addition, IMA downregulated the mRNA abundances of vascular cell adhesion molecule 1, intercellular adhesion molecule 1, IL-1β, IL-6, and tumor necrosis factor-α(TNF-α) expression. The phosphorylation of p65, nuclear factor-kappa B inhibitor alpha (IκBα), p38, extracellular signal-regulated kinase, and Jun N-terminal kinase induced by LPS were attenuated after IMA treatment in vivo and in vitro. IMA modulates the nuclear factor-kappa B and mitogen-activated protein kinase signaling pathways and the production of pro-inflammatory cytokines to prevent cellular damage due to LPS infection. These results indicate that IMA may be a potential modulator of LPS-induced ALI.

Inhibiting autophagy further promotes Ginkgolide B's anti-osteoclastogenesis ability

Excessive osteoclast activity could cause skeletal diseases including osteoporosis. Additionally, autophagy plays an initial role in osteoclast differentiation and function. Ginkgolide B (GB), a key compound in Ginkgo biloba, improves bone mass and suppresses mature osteoclast formation in vitro. This study examines the role of GB role in regulating osteoclast formation via autophagy. Using murine bone marrow-derived macrophages in vitro, we explored GB's effects on autophagy and osteoclast formation. We also assessed bone loss prevention in an ovariectomized (OVX) mouse model using GB combined with an autophagy inhibitor. Tartrate-resistant acid phosphatase staining was used to observe osteoclast formation. Autophagy-related proteins and intracellular microtubule associated protein 1 light chain 3 beta puncta were observed using western blotting and immunofluorescence. The impact of GB on OVX mice was evaluated using micro-computed tomography and hematoxylin and eosin staining. GB directly promoted autophagy in osteoclast precursors (OCPs), but inhibited osteoclast differentiation by reducing receptor activator of nuclear factor kappa B ligand (RANKL)-induced autophagy. GB inhibits the phosphorylation of RANKL downstream signaling pathways, such as Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK). Anisomycin (ANI), a JNK activator, reversed GB's inhibitory effects on RANKL-induced autophagy and osteoclastogenesis. Inhibiting autophagy using 3-Methyladenine (3-MA) or small interfering RNA significantly suppressed osteoclast differentiation both in vitro and in vivo. Our findings suggested that GB inhibits osteoclast formation by decreasing JNK phosphorylation and autophagy under RANKL stimulation. Interestingly, GB also directly promotes autophagy in OCPs. Thus, GB markedly reduces osteoclast differentiation and prevents bone loss, with its anti-osteoclastogenesis effect being enhanced by 3-MA. Accordingly, inhibiting GB-induced direct autophagy could further increase its therapeutic effect on bone disease resulting from excessive osteoclast activity.

The JNK signalling pathway gene BmJun is involved in the regulation of egg quality and production in the silkworm, Bombyx mori.

The Jun N-terminal kinase (JNK) signalling pathway has a key role in tissue remodelling during insect metamorphosis by regulating programmed cell death. However, multiple members of the JNK pathway in Lepidoptera remain uncharacterized. In this study, two key genes of the JNK pathway, BmJun and BmFos, were cloned from the silkworm Bombyx mori, a lepidopteran model insect, and their effects on reproductive development were investigated. BmJun and BmFos encode 239 and 380 amino acids, respectively. Both proteins have typical basic leucine zipper domains and form a BmJUN-BmFOS dimer activator protein to exert transcriptional regulation. During the wandering stage of silkworm development, interference in BmJun expression had no effect on pupation, whereas B. mori vitellogenin (BmVg) expression, which is essential for egg development, was suppressed in the fat body and egg laying was significantly reduced. Additionally, numerous eggs appeared shrivelled and deformed, suggesting that they were nutritionally stunted. Inhibition of the JNK pathway caused abnormal pupal metamorphosis, an increase in shrivelled, unfertilized eggs, a decrease in fat body synthesis, and accumulation of BmVg in the ovaries of female B. mori. The results indicated that BmJUN and BmFOS can form an AP-1 dimer. Interfering with BmJun or inhibiting the phosphorylation of BmJUN leads to a reduction in the synthesis of BmVg in the fat body and its accumulation in the ovaries, thereby affecting the quality and production of the progeny eggs. These findings suggest that regulating Jun in the JNK pathway could be a potential way to inhibit female reproduction in Lepidoptera.

Wnt-5a Signaling Mediates Metaplasticity at Hippocampal CA3–CA1 Synapses in Mice

Wnt signaling plays a role in synaptic plasticity, but the specific cellular events and molecular components involved in Wnt signaling-mediated synaptic plasticity are not well defined. Here, we report a change in the threshold required to induce synaptic plasticity that facilitates the induction of long-term potentiation (LTP) and inhibits the induction of long-term depression (LTD) during brief exposure to the noncanonical ligand Wnt-5a. Both effects are related to the metaplastic switch of hippocampal CA3–CA1 synaptic transmission, a complex mechanism underlying the regulation of the threshold required to induce synaptic plasticity and of synaptic efficacy. We observed an early increase in the amplitude of field excitatory postsynaptic potentials (fEPSPs) that persisted over time, including after washout. The first phase involves an increase in the fEPSP amplitude that is required to trigger a spontaneous second phase that depends on Jun N-terminal kinase (JNK) and N-methyl D-aspartate receptor (NMDAR) activity. These changes are prevented by treatment with secreted frizzled-related protein 2 (sFRP-2), an endogenous antagonist of Wnt ligands. Here, we demonstrate the contribution of Wnt-5a signaling to a process associated with metaplasticity at CA3–CA1 synapses that favors LTP over LTD.Graphical

Propafenone facilitates mitochondrial-associated ferroptosis and synergizes with immunotherapy in melanoma

BackgroundDespite the successful application of immunotherapy, both innate and acquired resistance are typical in melanoma. Ferroptosis induction appears to be a potential strategy to enhance the effectiveness of immunotherapy. However,...

Selective Covalent Inhibiting JNK3 by Small Molecules for Parkinson's Diseases

Abstractc‐Jun N‐terminal kinases (JNKs) including JNK1/2/3 are key members of mitogen‐activated protein kinase family. Wherein JNK3 is specifically expressed in brain and emerges as therapeutic target, especially for neurodegenerative diseases. However, developing JNK3 selective inhibitors as chemical probes to investigate its therapeutic potential in diseases remains challenging. Here, we adopted the covalent strategy for identifying JNK3‐selective covalent inhibitor JC16I, with high inhibitory activity against JNK3. Despite targeting a conserved cysteine in the vicinity of ATP pocket in JNK family, JC16I exerted a greater than 160‐fold selectivity for JNK3 over JNK1/2. Importantly, even at low concentration, JC16I showed enhanced and long‐lasting inhibition against cellular JNK3. In addition, its alkyne‐containing probe JC‐P1 could label JNK3 in SH‐SY5Y cell lysate and living cells, with good proteome‐wide selectivity. JC16I selectively suppressed the abnormal activation of JNK3 signaling and sufficiently exhibited neuroprotective effect in Parkinson's diseases (PD) models. Overall, our findings highlight the potential of developing isoform‐selective and cell‐active JNK3 inhibitors by covalent drug design strategy targeting a conserved cysteine. This work not only provides a valuable chemical probe for JNK3‐targeted investigations in vitro and in vivo but also opens new avenues for the treatment of PD.

Paraptosis-A Distinct Pathway to Cell Death.

Cell death is a critical biological process necessary for development, tissue maintenance, and defense against diseases. To date, more than 20 forms of cell death have been identified, each defined by unique molecular pathways. Understanding these different forms of cell death is essential for investigating the pathogenesis of diseases such as cancer, neurodegenerative disorders, and autoimmune conditions and developing appropriate therapies. Paraptosis is a distinct form of regulated cell death characterized by cytoplasmic vacuolation and dilatation of cellular organelles like the mitochondria and endoplasmic reticulum (ER). It is regulated by several signaling pathways, for instance, those associated with ER stress, calcium overload, oxidative stress, and specific cascades such as insulin-like growth factor I receptor (IGF-IR) and its downstream signaling pathways comprising mitogen-activated protein kinases (MAPKs) and Jun N-terminal kinase (JNK). Paraptosis has been observed in diverse biological contexts, including development and cellular stress responses in neuronal, retinal, endothelial, and muscle cells. The induction of paraptosis is increasingly important in anticancer therapy, as it targets non-apoptotic stress responses in tumor cells, which can be utilized to induce cell death. This approach enhances treatment efficacy and addresses drug resistance, particularly in cases where cancer cells are resistant to apoptosis. Combining paraptosis-inducing agents with traditional therapies holds promise for enhancing treatment efficacy and overcoming drug resistance, suggesting a valuable strategy in anticancer therapy.

Galloyl–RGD, Derived from a Fusion of Phytochemicals and RGD Peptides, Regulates Photoaging via the MAPK/AP-1 Mechanism in Human Dermal Fibroblasts

Galloyl–RGD is a novel compound that combines gallic acid with RGD peptides (arginine, glycine, and asparaginic acid) to overcome the problems associated with gallic acid, such as instability at high temperatures and low solubility. In this study, we investigated the effects and molecular mechanisms of action of galloyl–RGD on UVB-induced skin photoaging in human dermal fibroblasts-neonatal (HDF-n). Galloyl–RGD increased collagen synthesis by inhibiting UVB-induced MMP-1 via inhibiting extracellular signal-regulated kinase and Jun N-terminal kinase and their downstream mitogen-activated protein kinase signaling, which are known to be representative photoaging mechanisms. The results of this study will be helpful for understanding the anti-photoaging effect and mechanism of galloyl–RGD and its future applications in the cosmetic and pharmaceutical industries.

Dachaihu Decoction alleviates chronic pancreatitis by regulating MAPK signaling pathway: Insights from network pharmacology and experimental validation

Ethnopharmacological relevanceChronic pancreatitis (CP), a syndrome characterized by inflammatory fibrosis, can impair both the internal and external secretory functions of the pancreas. The global incidence of this disease is gradually increasing. However, the exact pathogenesis remains unclear, resulting in a lack of targeted clinical therapies. According to the principles of traditional Chinese medicine, CP can be attributed to Shaoyang and Yangming syndromes, which manifest as abdominal pain and hypochondriac distension. Dachaihu Decoction (DCHD) is a classic formula from the “Treatise on Febrile and Miscellaneous Disease.” It is frequently prescribed for conditions associated with combined Shaoyang and Yangming syndromes. However, the specific mechanisms by which DCHD prevents and treats CP remain unclear and require further investigation. Aim of the studyUsing a holistic methodology, including network pharmacology, molecular docking, transcriptomic profiling, and animal experimentation, we explored the potential therapeutic mechanisms of DCHD in CP. Materials and methodsIn a mouse model, caerulein was used to induce CP, and DCHD was administered via gastric lavage to assess its therapeutic effect on pancreatic injury caused by caerulein-induced CP. Subsequently, pancreatic tissues were collected for transcriptomic analysis. Screening of DCHD-active ingredient-target pathways for CP treatment was conducted using network pharmacology and further preliminary validation was performed using molecular docking techniques. Additionally, in vivo and in vitro validation was conducted using animal and cells experiments based on the predicted results. ResultsOur findings suggest that DCHD ameliorates pancreatic acinar cell injury, pancreatic inflammation, and fibrosis in mice with CP. Network pharmacology identified 385 potential targets of DCHD associated with CP. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the therapeutic effect of DCHD on CP may be linked to the mitogen-activated protein kinase (MAPK) signaling pathway. Transcriptomic data supported this finding, as it confirmed that DCHD inhibited the pancreatic MAPK signaling pathway in CP. Molecular docking studies further revealed that the top ten active components of DCHD exhibited strong docking activity with key molecules within the MAPK signaling pathway. Finally, animal experiments confirmed that DCHD effectively reduced the phosphorylation of P38, Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) in pancreatic tissues. In addition, the expression of p-P38, p-JNK, and p-ERK was reduced in pancreatic stellate cells and macrophages in the DCHD group. We further treated CP mice, human pancreatic stellate cell line (hPSCs), and macrophage cell line RAW264.7 with the active component baicalin from DCHD, and found that baicalin effectively reduced pancreatic damage in CP. Additionally, the expression of key proteins in the MAPK signaling pathway was significantly decreased in both hPSCs and RAW264.7. ConclusionIn summary, DCHD plays an important role in the treatment of chronic pancreatitis, and it may become a promising drug against the progression of CP. The role of DCHD in alleviating pancreatic inflammatory cell infiltration and fibrosis may be related to the regulation of the MAPK signaling pathway.

An unscheduled switch to endocycles induces a reversible senescent arrest that impairs growth of the Drosophila wing disc.

A programmed developmental switch to G / S endocycles results in tissue growth through an increase in cell size. Unscheduled, induced endocycling cells (iECs) promote wound healing but also contribute to cancer. Much remains unknown, however, about how these iECs affect tissue growth. Using the D. melanogaster wing disc as model, we find that populations of iECs initially increase in size but then subsequently undergo a heterogenous arrest that causes severe tissue undergrowth. iECs acquired DNA damage and activated a Jun N-terminal kinase (JNK) pathway, but, unlike other stressed cells, were apoptosis-resistant and not eliminated from the epithelium. Instead, iECs entered a JNK-dependent and reversible senescent-like arrest. Senescent iECs promoted division of diploid neighbors, but this compensatory proliferation did not rescue tissue growth. Our study has uncovered unique attributes of iECs and their effects on tissue growth that have important implications for understanding their roles in wound healing and cancer.

Regulatory T cells protect against diabetic cardiomyopathy in db/db mice.

Regulatory T cells (Tregs) have protected against many cardiovascular diseases. This study was intended to explore the effect of Tregs on diabetic cardiomyopathy (DCM) using a db/db mouse model. Eight-week-old male db/db mice were randomly divided into four groups: the control group, administered 200 μL phosphate-buffered saline; the small-dose Treg group, administered 105 Tregs; the large-dose Treg group, administered 106 Tregs; and the PC group, administered 100 μg anti-CD25 specific antibody (PC61) and 106 Tregs. After 12 weeks, mice were euthanized. Transthoracic echocardiography was carried out at the beginning and end of the experiment. Relevant basic experiments to evaluate the effects of Tregs on DCM were carried out. Echocardiography showed that the impaired diastolic and systolic functions were significantly improved in mice administered large-dose Tregs. Large-dose Tregs significantly ameliorated myocardial hypertrophy and fibrosis, and decreased hypertrophic gene expression and collagen deposition. The protective effects of Tregs on diabetic hearts were associated with decreased oxidative stress, inflammatory response and apoptosis. In addition, Tregs promoted the activation of the phosphatidylinositol 3-kinase-protein kinase B signaling pathway, whereas they inhibited extracellular signal-regulated kinase 1/2 and Jun N-terminal kinase phosphorylation, which might be responsible for the cardioprotective role of Tregs against DCM. Tregs ameliorated myocardial hypertrophy and fibrosis, improved cardiac dysfunction, and protected against DCM progression in db/db mice. The mechanisms involved a decrease of inflammatory response, oxidative stress and apoptosis, which might be mediated by phosphatidylinositol 3-kinase-protein kinase B and mitogen-activated protein kinase pathways. Hence, Tregs might serve as a promising therapeutic approach for DCM treatment.

Propolis: a natural compound with potential as an adjuvant in cancer therapy - a review of signaling pathways.

Propolis is a natural product used in cancer treatment, which is produced by bees via different sources. The chemical composition of Propolis is determined based on the climatic and geographical conditions, as well as harvesting time and method. This compound has been the subject of numerous investigational endeavors due to its expansive therapeutic capacity which includes antibacterial, anti-fungal, anti-inflammatory, anti-oxidant, anti-viral, and anti-cancer effects. The growing incidence rate of different cancers necessitates the need for developing novel preventive and therapeutic strategies. Chemotherapy, radiotherapy, and stem cell therapy have proved effective in cancer treatment, regardless of the adverse events associated with these modalities. Clinical application of natural compounds such as Propolis may confer promise as an adjuvant therapeutic intervention, particularly in certain subpopulations of patients that develop adverse events associated with anticancer regimens. The diverse biologically active compounds of propolis are believed to confer anti-cancer potential by modulation of critical signaling cascades such as caffeic acid phenethyl ester, Galangin, Artepillin C, Chrysin, Quercetin, Caffeic acid, Nymphaeols A and C, Frondoside A, Genistein, p-coumaric acid, and Propolin C. This review article aims to deliver a mechanistic account of anti-cancer effects of propolis and its components. Propolis can prevent angiogenesis by downregulating pathways involving Jun-N terminal kinase, ERK1/2, Akt and NF-ƘB, while counteracting metastatic progression of cancer by inhibiting Wtn2 and FAK, and MAPK and PI3K/AKT signaling pathways. Moreover, propolis or its main components show regulatory effects on cyclin D, CDK2/4/6, and their inhibitors. Additionally, propolis-induced up-regulation of p21 and p27 may result in cell cycle arrest at G2/M or G0/G1. The broad anti-apoptotic effects of propolis are mediated through upregulation of TRAIL, Bax, p53, and downregulation of the ERK1/2 signaling pathway. Considering the growing body of evidence regarding different anti-cancers effects of propolis and its active components, this natural compound could be considered an effective adjuvant therapy aimed at reducing related side effects associated with chemotherapy and radiotherapy.

Postmortem Immunohistochemical Findings in Early Acute Myocardial Infarction: A Systematic Review.

The diagnosis of early acute myocardial infarction is of particular importance in forensic practice considering the frequency of sudden cardiac death and the difficulty of positively identifying it through classical histological methods if survival is less than 6 h. This article aims to analyze potential immunohistochemical markers that could be useful in diagnosing acute myocardial infarction within the first 6 h of its onset. We conducted an extensive evaluation of the literature according to the PRISMA guidelines for reporting systematic literature reviews. We searched the Web of Science and PubMed databases from their inception to 2023 using the following keywords: "myocardial infarction" and "immunohistochemistry". Fifteen studies met the inclusion criteria. Immunohistochemical markers as complement factors and CD59, myoglobin, fibrinogen, desmin, tumor necrosis factor alpha (TNF-α), P-38, JNK (Jun N Terminal Kinase), transforming growth factor β1 (TGF-β1), cardiac troponins, fibronectin, H-FABP (heart fatty acid binding protein), dityrosine, fibronectin, CD15, IL-1β, IL-6, IL-15, IL-8, MCP-1, ICAM-1, CD18, and tryptase can be used to identify the first six hours of acute myocardial infarction. These markers are mostly studied in experimental animal models. It is necessary to conduct extensive studies on human myocardial tissue fragments, which will involve the analysis of several immunohistochemical markers and careful analysis of the available data on perimortem events, resuscitation, and postmortem intervals in the context of a uniform laboratory methodology.

The Drosophila tumor necrosis factor Eiger promotes Myc supercompetition independent of canonical Jun N-terminal kinase signaling.

Numerous factors have been implicated in the cell-cell interactions that lead to elimination of cells via cell competition, a context-dependent process of cell selection in somatic tissues that is based on comparisons of cellular fitness. Here, we use a series of genetic tests in Drosophila to explore the relative contribution of the pleiotropic cytokine tumor necrosis factor α (TNFα) in Myc-mediated cell competition (also known as Myc supercompetition or Myc cell competition). We find that the sole Drosophila TNF, Eiger (Egr), its receptor Grindelwald (Grnd/TNF receptor), and the adaptor proteins Traf4 and Traf6 are required to eliminate wild-type "loser" cells during Myc cell competition. Although typically the interaction between Egr and Grnd leads to cell death by activating the intracellular Jun N-terminal kinase (JNK) stress signaling pathway, our experiments reveal that many components of canonical JNK signaling are dispensable for cell death in Myc cell competition, including the JNKKK Tak1, the JNKK Hemipterous and the JNK Basket. Our results suggest that Egr/Grnd signaling participates in Myc cell competition but functions in a role that is largely independent of the JNK signaling pathway.

Scutellarin alleviates renal ischemia-reperfusion injury by inhibiting the MAPK pathway and pro-inflammatory macrophage polarization.

Renal ischemia-reperfusion injury (IRI) is an integral process in renal transplantation, which results in compromised graft survival. Macrophages play an important role in both the early inflammatory period and late fibrotic period in response to IRI. In this study, we investigated whether scutellarin (SCU) could protect against renal IRI by regulating macrophage polarization. Mice were given SCU (5-50 mg/kg) by gavage 1 h earlier, followed by a unilateral renal IRI. Renal function and pathological injury were assessed 24 h after reperfusion. The results showed that administration of 50 mg/kg SCU significantly improved renal function and renal pathology in IRI mice. In addition, SCU alleviated IRI-induced apoptosis. Meanwhile, it reduced macrophage infiltration and inhibited pro-inflammatory macrophage polarization. Moreover, in RAW 264.7 cells and primary bone marrow-derived macrophages (BMDMs) exposed to SCU, we found that 150 μM SCU inhibited these cells to polarize to an inflammatory phenotype induced by lipopolysaccharide (LPS) and interferon-γ (IFN-γ). However, SCU has no influence on anti-inflammatory macrophage polarization invivo and invitro induced by in interleukin-4 (IL-4). Finally, we explored the effect of SCU on the activation of the mitogen-activated protein kinase (MAPK) pathway both invivo and invitro. We found that SCU suppressed the activation of the MAPK pathway, including the extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK), and p38. Our results demonstrated that SCU protects the kidney against IRI by inhibiting macrophage infiltration and polarization toward pro-inflammatory phenotype via the MAPK pathway, suggesting that SCU may be therapeutically important in treatment of IRI.

Crosstalk of MAP3K1 and EGFR signaling mediates gene-environment interactions that block developmental tissue closure

Aberrant regulation of signal transduction pathways can adversely derail biological processes for tissue development. One such process is the embryonic eyelid closure that is dependent on the Mitogen-Activated Protein Kinase Kinase Kinase 1 (MAP3K1). Map3k1 knockout in mice results in defective eyelid closure and an autosomal recessive eye-open at birth phenotype. We have shown that in utero exposure to dioxin, a persistent environmental toxicant, induces the same eye defect in Map3k1+/- heterozygous but not wild type pups. Here we explore the mechanisms of the Map3k1 (gene) and dioxin (environment) interactions (GxE) underlying defective eyelid closure. We show that, acting through the Aryl Hydrocarbon Receptor (AHR), dioxin activates Epidermal Growth Factor Receptor (EGFR) signaling, which in turn depresses MAP3K1-dependent Jun N-terminal Kinase (JNK) activity. The dioxin mediated JNK repression is moderate but is exacerbated by Map3k1 heterozygosity. Therefore, dioxin exposed Map3k1+/- embryonic eyelids have a marked reduction of JNK activity, accelerated differentiation and impeded polarization in the epithelial cells. Knocking out Ahr or Egfr in eyelid epithelium attenuates the open-eye defects in dioxin-treated Map3k1+/- pups, whereas knockout of Jnk1 and S1pr that encodes the Sphigosin-1-phosphate (S1P) receptors upstream of the MAP3K1-JNK pathway potentiates the dioxin toxicity. Our novel findings show that the crosstalk of AHR, EGFR and S1P-MAP3K1-JNK pathways determines the outcome of dioxin exposure. Thus, gene mutations targeting these pathways are potential risk factors for the toxicity of environmental chemicals.

Xiaowugui decoction alleviates experimental rheumatoid arthritis by suppressing Rab5a-mediated TLR4 internalization in macrophages

BackgroundRheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by exacerbated synovial inflammation and joint destruction. Recent studies suggest toll-like receptor 4 (TLR4) internalization facilitate inflammatory response of macrophage. The role of TLR4 internalization in the pathogenesis of RA is unknown. PurposeTo investigate the role and mechanism of TLR4 internalization in macrophage inflammatory response of RA and explore whether TLR4 internalization mediates the anti-arthritic effect of Xiaowugui (XWG) decoction, a patented herbal formula used in China. MethodsThe co-expression of TLR4 and the internalization marker, early endosome antigen 1 (EEA1), in the synovial samples of RA patients and joint tissue of collagen-induced arthritis (CIA) mice, were evaluated using immunofluorescence. The effect of Rab5a-mediated early internalization of TLR4 on the activation induced by lipopolysaccharide (LPS) in RAW264.7 cells was investigated using small interfering RNAs that act against Rab5a. CIA was induced in Rab5a−/− mice to evaluate the role of Rab5a in vivo. The disease progression and expression of Rab5a and TLR4 in the joint tissue were evaluated in CIA mice treated with XWG. Inflammatory factors production, TLR4 internalization, and activation of downstream signaling pathways were examined in RAW264.7 cells treated with XWG in vitro. ResultsThe co-expression and co-localization of TLR4 and EEA1 were elevated in the synovial samples of RA patients and joint tissue of CIA mice. Pharmaceutical inhibition of TLR4 internalization reduced macrophages inflammatory responses induced by LPS. The co-expression and co-localization of Rab5a and TLR4 were significantly increased in macrophages treated with LPS. Silencing Rab5a reduced LPS-induced TLR4 internalization, inflammatory factors production, and phosphorylation of Jun N-terminal kinases (JNK) and p65. Genetic deletion of Rab5a inhibited TLR4 internalization and the development of arthritis in vivo. The co-expression of TLR4 and Rab5a was also elevated in the synovial samples of RA patients. XWG treatment of mice with CIA alleviated arthritis and reduced the co-expression of Rab5a and TLR4 in the joint tissue. XWG treatment of macrophage inhibited LPS-induced IL-6 and TNF-α production, co-expression of Rab5a and TLR4, and phosphorylation of JNK and p65. ConclusionsOur findings highlight the pathogenic role of TLR4 internalization in patients with RA and identify a novel Rab5a-dependent internalization pathway that promotes macrophage inflammatory response. XWG treatment demonstrated outstanding therapeutic effects in experimental arthritis, and targeting the Rab5a-mediated internalization of TLR4 may be the main underlying mechanism.

A Tumor-Specific Molecular Network Promotes Tumor Growth in Drosophila by Enforcing a Jun N-Terminal Kinase-Yorkie Feedforward Loop.

Cancer cells expand rapidly in response to altered intercellular and signaling interactions to achieve the hallmarks of cancer. Impaired cell polarity combined with activated oncogenes is known to promote several hallmarks of cancer, e.g., activating invasion by increased activity of Jun N-terminal kinase (JNK) and sustained proliferative signaling by increased activity of Hippo effector Yorkie (Yki). Thus, JNK, Yki, and their downstream transcription factors have emerged as synergistic drivers of tumor growth through pro-tumor signaling and intercellular interactions like cell competition. However, little is known about the signals that converge onto JNK and Yki in tumor cells and enable tumor cells to achieve the hallmarks of cancer. Here, using mosaic models of cooperative oncogenesis (RasV12,scrib-) in Drosophila, we show that RasV12,scrib- tumor cells grow through the activation of a previously unidentified network comprising Wingless (Wg), Dronc, JNK, and Yki. We show that RasV12,scrib- cells show increased Wg, Dronc, JNK, and Yki signaling, and all these signals are required for the growth of RasV12,scrib- tumors. We report that Wg and Dronc converge onto a JNK-Yki self-reinforcing positive feedback signal-amplification loop that promotes tumor growth. We found that the Wg-Dronc-Yki-JNK molecular network is specifically activated in polarity-impaired tumor cells and not in normal cells, in which apical-basal polarity remains intact. Our findings suggest that the identification of molecular networks may provide significant insights into the key biologically meaningful changes in signaling pathways and paradoxical signals that promote tumorigenesis.