Protein Kinases JNK Research Articles

The Role and Efficacy of JNK Inhibition in Inducing Lung Cancer Cell Death Depend on the Concentration of Cisplatin.

Toxicity and the emergence of resistance are the main challenges in cancer treatment. The optimal dose of cisplatin, one of the most widely used chemotherapeutic anticancer drugs, is currently being widely debated. Furthermore, the dose-dependent molecular mechanisms of its action are poorly understood. To assess the role of protein kinase JNK (cJun N-terminal kinase) signaling in lung cancer treatment, we combined small-molecule JNK inhibitors and cisplatin. Wild-type p53 (tumor suppressor transcription factor TP53) and mutated RAS-bearing lung adenocarcinoma cell line A549 was used as a model in our studies. Here, we demonstrate cisplatin concentration-dependent opposing roles of JNK in killing cancer cells: a cell-protective role at low cisplatin concentrations and an apoptosis-promoting (or neutral) role at high concentrations. Time- and dose-dependent activation of pro-survival protein kinase AKT and TP53 was shown, with similar activation dynamics in cells exposed to different (low and high) cisplatin concentrations. Selective inhibition of AKT and activation of TP53 (expression and phosphorylation) led to a decrease in cell survival, indicating their involvement in cisplatin-induced cell death regulation. The activation levels of TP53 and AKT in cisplatin-treated A549 cells after cotreatment with the JNK inhibitor SP600125 correlated with their role in regulating cell death. TP53 and AKT were proposed as signaling proteins mediating the outcome of JNK inhibition in A549 cells exposed to different concentrations of cisplatin. Our findings suggest that a combination of stress kinase JNK inhibition and low-dose cisplatin, together with manipulation of drug-induced signaling, could be considered as a promising treatment strategy for certain lung cancers.

Identification of potent schistosomicidal compounds predicted as type II-kinase inhibitors against Schistosoma mansoni c-Jun N-terminal kinase SMJNK

IntroductionSchistosomiasis has for many years relied on a single drug, praziquantel (PZQ) for treatment of the disease. Immense efforts have been invested in the discovery of protein kinase (PK) inhibitors; however, given that the majority of PKs are still not targeted by an inhibitor with a useful level of selectivity, there is a compelling need to expand the chemical space available for synthesizing new, potent, and selective PK inhibitors. Small-molecule inhibitors targeting the ATP pocket of the catalytic domain of PKs have the potential to become drugs devoid of (major) side effects, particularly if they bind selectively. This is the case for type II PK inhibitors, which cause PKs to adopt the so-called DFG-out conformation, corresponding to the inactive state of the enzyme.MethodsThe goal was to perform a virtual screen against the ATP pocket of the inactive JNK protein kinase. After virtually screening millions of compounds, Atomwise provided 85 compounds predicted to target c-Jun N-terminal kinase (JNK) as type II inhibitors. Selected compounds were screened in vitro against larval stage (schistosomula) of S. mansoni using the XTT assay. Adult worms were assessed for motility, attachment, and pairing stability. Active compounds were further analyzed by molecular docking against SmJNK.ResultsIn total, 33 compounds were considered active in at least one of the assays, and two compounds were active in every in vitro screening assay. The two most potent compounds presented strong effects against both life stages of the parasite, and microscopy analysis showed phenotypic alterations on the tegument, in the gonads, and impairment of cell proliferation.ConclusionThe approach to screen type II kinase inhibitors resulted in the identification of active compounds that will be further developed against schistosomiasis.

Initiation of a ZAKα-dependent ribotoxic stress response by the innate immunity endoribonuclease RNase L

RNase L is an endoribonuclease of higher vertebrates that functions in antiviral innate immunity. Interferons induce oligoadenylate synthetase enzymes that sense double-stranded RNA of viral origin leading to the synthesis of 2',5'-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L remodels the host cell transcriptome. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A is directly introduced into cells. Here, we report that RNase L activation by 2-5A causes a ribotoxic stress response involving the MAP kinase kinase kinase (MAP3K) ZAKα, MAP2Ks, and the stress-activated protein kinases JNK and p38α. RNase L activation profoundly alters the transcriptome by widespread depletion of mRNAs associated with different cellular functions but also by JNK/p38α-stimulated induction of inflammatory genes. These results show that the 2-5A/RNase L system triggers a protein kinase cascade leading to proinflammatory signaling and apoptosis.

Evaluation of vector susceptibility in Aedes aegypti and Culex pipiens pallens to Tibet orbivirus.

Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in different types of vertebrate and mosquito cells, with its neutralizing antibodies detected in cattle and goats. However, despite being isolated from Culicoides midges, Anopheles, and Culex mosquitoes, there has been a notable absence of systematic studies on its vector competence. Thus, in this study, Aedes aegypti and Culex pipiens pallens were reared in the laboratory to measure vector susceptibility through blood-feeding infection. Furthermore, RNA sequencing was used to examine the overall alterations in the Ae. aegypti transcriptome following TIBOV infection. The results revealed that Ae. aegypti exhibited a high susceptibility to TIBOV compared to Cx. p. pallens. Effective replication of the virus in Ae. aegypti midguts occurred when the blood-feeding titer of TIBOV exceeded 105 plaque-forming units mL-1. Nevertheless, only a few TIBOV RNA-positive samples were detected in the saliva of Ae. aegypti and Cx. p. pallens, suggesting that these mosquito species may not be the primary vectors for TIBOV. Moreover, at 2 dpi of TIBOV, numerous antimicrobial peptides downstream of the Toll and Imd signaling pathways were significantly downregulated in Ae. aegypti, indicating that TIBOV suppressed mosquitos' defense to survive in the vector at an early stage. Subsequently, the stress-activated protein kinase JNK, a crucial component of the MAPK signaling pathway, exhibited significant upregulation. Certain genes were also enriched in the MAPK signaling pathway in TIBOV-infected Ae. aegypti at 7 dpi.IMPORTANCETibet orbivirus (TIBOV) is an understudied arbovirus of the genus Orbivirus. Our study is the first-ever attempt to assess the vector susceptibility of this virus in two important mosquito vectors, Aedes aegypti and Culex pipiens pallens. Additionally, we present transcriptome data detailing the interaction between TIBOV and the immune system of Ae. aegypti, which expands the knowledge about orbivirus infection and its interaction with mosquitoes.

Role of angiotensin II and neuroendocrine factors in immunological regulation in patients with coronary heart disease: prospective cross-sectional study

BACKGROUND: Among chronic noncommunicable diseases, cardiovascular diseases, particularly coronary heart disease (CHD), are the leading cause of death. The rennin-angiotensin-aldosterone system plays an important role in CHD development and progression; however, its role in the regulation of immunoneuroendocrine interactions requires further analysis.
 OBJECTIVE: To study the relationship between angiotensin II (AT II) and molecular regulators of the activity of whole blood mononuclear cells (MNCs) in patients with angina pectoris.
 MATERIALS AND METHODS: This cross-sectional study enrolled 65 patients with exertional angina aged 45–67 years, including 19 apparently healthy individuals. The levels of interleukins (ILs), transforming growth factor-β1 (TGF-β1), prostaglandin E2 (PG E2), serotonin, thyroid-stimulating hormone (TSH), and AT II in the blood serum were determined. In MNCs, the concentrations of protein kinases FAK, JNK, p38, and ERK, signal transducers, and activators of transcription (STAT 3, 5A, and 6) were determined.
 RESULTS: In patients with coronary artery disease, the production of TGF-β1 increased by 7.2% (p=0.00001), AT II by 136.9% (p=0.0001), serotonin by 129.0% (p=0.00001), IL-18 by 92.5% (p=0.00001), TSH by 51.7% (p=0.0012), ERK protein kinase content by 86.4% (p=0.0001), JNK by 56.8% (p=0.0001), and FAK by 55.3% (p=0.00002). The levels of IL-15 also decreased by 38.1% (p=0.0001), PG E2 by 39.5% (p=0.0001), and STAT3 by 52.5% (p=0.0001).
 CONCLUSION: The nature of the identified relationships among the analyzed factors allows us to consider AT II as a factor that ensures adaptive coupling of immune and neuroendocrine regulatory mechanisms in patients with coronary artery disease, contributing to a change in the balance between macrophages and T-helper types 1 and 2.

The Inhibition of Mitogen-Activated Protein Kinases (MAPKs) and NF-κB Underlies the Neuroprotective Capacity of a Cinnamon/Curcumin/Turmeric Spice Blend in Aβ-Exposed THP-1 Cells.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by an increased level of β-amyloid (Aβ) protein deposition in the brain, yet the exact etiology remains elusive. Nowadays, treatments only target symptoms, thus the search for novel strategies is constantly stimulated, and looking to natural substances from the plant kingdom. The aim of this study was to investigate the neuroprotective effects of a spice blend composed of cinnamon bark and two different turmeric root extracts (CCSB) in Aβ-exposed THP-1 cells as a model of neuroinflammation. In abiotic assays, CCSB demonstrated an antioxidant capacity up to three times stronger than Trolox in the ORAC assay, and it reduced reactive oxygen species (ROS) induced by the amyloid fragment in THP-1 cells by up to 39.7%. Moreover, CCSB lowered the Aβ stimulated secretion of the pro-inflammatory cytokines IL-1β and IL-6 by up to 24.9% and 43.4%, respectively, along with their gene expression by up to 25.2% and 43.1%, respectively. The mechanism involved the mitogen-activated protein kinases ERK, JNK and p38, whose phosphorylation was reduced by up to 51.5%, 73.7%, and 58.2%, respectively. In addition, phosphorylation of p65, one of the five components forming NF-κB, was reduced by up to 86.1%. Our results suggest that CCSB can counteract the neuroinflammatory stimulus induced by Aβ-exposure in THP-1 cells, and therefore can be considered a potential candidate for AD management.

A tri-herb formulation protects against ethanol-induced mouse liver injury and downregulates mitogen-activated protein kinase phosphatase 1

BackgroundA tri-herb formulation comprising Ganoderma (the dried fruiting body of Ganoderma lucidum), Puerariae Thomsonii Radix (the dried root of Pueraria thomsonii) and Hoveniae Semen (the dried mature seed of Hovenia acerba) —GPH for short— has been using for treating liver injury; however, the pharmacological basis of this application of GPH is unknown. This study aimed to investigate the liver protective effects and mechanisms of action of an ethanolic extract of GPH (GPHE) in mice. MethodsTo control the quality of GPHE, the contents of ganodermanontriol, puerarin and kaempferol in the extract were quantified by ultra-performance liquid chromatography. An ethanol (6 ml/kg, i.g.)-induced liver injury ICR mouse model was employed to investigate the hepatoprotective effects of GPHE. RNA-sequencing analysis and bioassays were performed to reveal the mechanisms of action of GPHE. ResultsThe contents of ganodermanontriol, puerarin and kaempferol in GPHE were 0.0632%, 3.627% and 0.0149%, respectively. Daily i.g. administration of 0.25, 0.5 or 1 g/kg of GPHE for 15 consecutive days suppressed ethanol (6 ml/kg, i.g., at day 15)-induced upregulation of serum AST and ALT levels and improved histological conditions in mouse livers, indicating that GPHE protects mice from ethanol-induced liver injury. Mechanistically, GPHE downregulated the mRNA level of Dusp1 (encoding MKP1 protein, an inhibitor of the mitogen-activated protein kinases JNK, p38 and ERK), and upregulated expression and phosphorylation of JNK, p38 and ERK, which are involved in cell survival in mouse liver tissues. Also, GPHE increased PCNA (a cell proliferation marker) expression and reduced TUNEL-positive (apoptotic) cells in mouse livers. ConclusionGPHE protects against ethanol-induced liver injury, and this effect of GPHE is associated with regulation of the MKP1/MAPK pathway. This study provides pharmacological justifications for the use of GPH in treating liver injury, and suggests that GPHE has potential to be developed into a modern medication for managing liver injury.

Stress-Activated Protein Kinase JNK Modulates Depression-like Behaviors in Mice.

Stress is considered as a major cause of depression. C-Jun N-terminal kinase (JNK) is a member of the stress-induced mitogen activated protein (MAP) kinase family which is often activated through phosphorylation. Clinical studies and animal experiments have found that abnormal phosphorylation/activation of JNK exists in the occurrence of various psychiatric diseases. Recently, several studies linked JNK kinase activity to depression. However, whether excessive activation of JNK activity is directly responsible for the occurrence of depression and the underlying mechanisms remain unclear. Here, we constructed a conditional transgenic mouse which is specifically expressing MKK7-JNK1 (CAJNK1) in the central nervous system. CAJNK1 mice showed activation of JNK and lead to depression-like behavior in mice. Transcriptome analysis indicates reduced expression of synaptic-associated genes in CAJNK1 mice brains. Consistently, we found abnormal dendritic spine development and PSD95 downregulation in CAJNK1 hippocampal neurons. Our studies provide compelling evidence that activation of JNK as an intrinsic factor leading to depression-like behavior in mice provides direct clues for targeting the JNK activity as a potential therapeutic strategy for depression.

BCI, an inhibitor of the DUSP1 and DUSP6 dual specificity phosphatases, enhances P2X7 receptor expression in neuroblastoma cells.

P2X7 receptor (P2RX7) is expressed strongly by most human cancers, including neuroblastoma, where high levels of P2RX7 are correlated with a poor prognosis for patients. Tonic activation of P2X7 receptor favors cell metabolism and angiogenesis, thereby promoting cancer cell proliferation, immunosuppression, and metastasis. Although understanding the mechanisms that control P2X7 receptor levels in neuroblastoma cells could be biologically and clinically relevant, the intracellular signaling pathways involved in this regulation remain poorly understood. Here we show that (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI), an allosteric inhibitor of dual specificity phosphatases (DUSP) 1 and 6, enhances the expression of P2X7 receptor in N2a neuroblastoma cells. We found that exposure to BCI induces the phosphorylation of mitogen-activated protein kinases p38 and JNK, while it prevents the phosphorylation of ERK1/2. BCI enhanced dual specificity phosphatase 1 expression, whereas it induced a decrease in the dual specificity phosphatase 6 transcripts, suggesting that BCI-dependent inhibition of dual specificity phosphatase 1 may be responsible for the increase in p38 and JNK phosphorylation. The weaker ERK phosphorylation induced by BCI was reversed by p38 inhibition, indicating that this MAPK is involved in the regulatory loop that dampens ERK activity. The PP2A phosphatase appears to be implicated in the p38-dependent dephosphorylation of ERK1/2. In addition, the PTEN phosphatase inhibition also prevented ERK1/2 dephosphorylation, probably through p38 downregulation. By contrast, inhibition of the p53 nuclear factor decreased ERK phosphorylation, probably enhancing the activity of p38. Finally, the inhibition of either p38 or Sp1-dependent transcription halved the increase in P2X7 receptor expression induced by BCI. Moreover, the combined inhibition of both p38 and Sp1 completely prevented the effect exerted by BCI. Together, our results indicate that dual specificity phosphatase 1 acts as a novel negative regulator of P2X7 receptor expression in neuroblastoma cells due to the downregulation of the p38 pathway.

Current insights in molecular characterization of non-alcoholic fatty liver disease and treatment.

There is a continuously rising incidence of non-alcoholic fatty liver disease (NAFLD) around the world, which parallels the increasing incidence of metabolic diseases. NAFLD is a range of liver conditions that contains simple non-alcoholic fatty liver and advanced non-alcoholic steatohepatitis. In serious cases, NAFLD may develop into cirrhosis or even liver cancer. NAFLD has an intense relationship with metabolic syndrome, type 2 diabetes mellitus. It is known that gut microbiota, and functional molecules such as adenosine monophosphate-activated protein kinase JNK, and peroxisome proliferator-activated receptors (PPARs) in progressing and treating NAFLD. Traditionally, the conventional and effective therapeutic strategy is lifestyle intervention. Nowadays, new medicines targeting specific molecules, such as farnesoid X receptor, PPARs, and GLP-1 receptor, have been discovered and shown beneficial effects on patients with NAFLD. In this article, we focus on the molecular mechanisms and therapeutic approaches to NAFLD.

Time and age dependent regulation of neuroinflammation in a rat model of mesial temporal lobe epilepsy: Correlation with human data.

Acute brain insults trigger diverse cellular and signaling responses and often precipitate epilepsy. The cellular, molecular and signaling events relevant to the emergence of the epileptic brain, however, remain poorly understood. These multiplex structural and functional alterations tend also to be opposing - some homeostatic and reparative while others disruptive; some associated with growth and proliferation while others, with cell death. To differentiate pathological from protective consequences, we compared seizure-induced changes in gene expression hours and days following kainic acid (KA)-induced status epilepticus (SE) in postnatal day (P) 30 and P15 rats by capitalizing on age-dependent differential physiologic responses to KA-SE; only mature rats, not immature rats, have been shown to develop spontaneous recurrent seizures after KA-SE. To correlate gene expression profiles in epileptic rats with epilepsy patients and demonstrate the clinical relevance of our findings, we performed gene analysis on four patient samples obtained from temporal lobectomy and compared to four control brains from NICHD Brain Bank. Pro-inflammatory gene expressions were at higher magnitudes and more sustained in P30. The inflammatory response was driven by the cytokines IL-1β, IL-6, and IL-18 in the acute period up to 72 h and by IL-18 in the subacute period through the 10-day time point. In addition, a panoply of other immune system genes was upregulated, including chemokines, glia markers and adhesion molecules. Genes associated with the mitogen activated protein kinase (MAPK) pathways comprised the largest functional group identified. Through the integration of multiple ontological databases, we analyzed genes belonging to 13 separate pathways linked to Classical MAPK ERK, as well as stress activated protein kinases (SAPKs) p38 and JNK. Interestingly, genes belonging to the Classical MAPK pathways were mostly transiently activated within the first 24 h, while genes in the SAPK pathways had divergent time courses of expression, showing sustained activation only in P30. Genes in P30 also had different regulatory functions than in P15: P30 animals showed marked increases in positive regulators of transcription, of signaling pathways as well as of MAPKKK cascades. Many of the same inflammation-related genes as in epileptic rats were significantly upregulated in human hippocampus, higher than in lateral temporal neocortex. They included glia-associated genes, cytokines, chemokines and adhesion molecules and MAPK pathway genes. Uniquely expressed in human hippocampus were adaptive immune system genes including immune receptors CDs and MHC II HLAs. In the brain, many immune molecules have additional roles in synaptic plasticity and the promotion of neurite outgrowth. We propose that persistent changes in inflammatory gene expression after SE leads not only to structural damage but also to aberrant synaptogenesis that may lead to epileptogenesis. Furthermore, the sustained pattern of inflammatory genes upregulated in the epileptic mature brain was distinct from that of the immature brain that show transient changes and are resistant to cell death and neuropathologic changes. Our data suggest that the epileptogenic process may be a result of failed cellular signaling mechanisms, where insults overwhelm the system beyond a homeostatic threshold.

Regulation of Stress-Activated Kinases in Response to Tacaribe Virus Infection and Its Implications for Viral Replication.

Arenaviruses include important zoonotic pathogens that cause hemorrhagic fever (e.g., Junín virus; JUNV) as well as other viruses that are closely related but apathogenic (e.g., Tacaribe virus; TCRV). We have found that, while TCRV and JUNV differ in their ability to induce apoptosis in infected cells, due to active inhibition of caspase activation by the JUNV nucleoprotein, both viruses trigger similar upstream pro-apoptotic signaling events, including the activation/phosphorylation of p53. In the case of TCRV, the pro-apoptotic factor Bad is also phosphorylated (leading to its inactivation). These events clearly implicate upstream kinases in regulating the induction of apoptosis. Consistent with this, here we show activation in TCRV-infected cells of the stress-activated protein kinases p38 and JNK, which are known to regulate p53 activation, as well as the downstream kinase MK2 and transcription factor c-Jun. We also observed the early transient activation of Akt, but not Erk. Importantly, the chemical inhibition of Akt, p38, JNK and c-Jun all dramatically reduced viral growth, even though we have shown that inhibition of apoptosis itself does not. This indicates that kinase activation is crucial for viral infection, independent of its downstream role in apoptosis regulation, a finding that has the potential to shed further light on the determinants of arenavirus pathogenesis, as well as to inform future therapeutic approaches.

Mulberry Ethanol Extract and Rutin Protect Alcohol-Damaged GES-1 Cells by Inhibiting the MAPK Pathway.

Mulberry extract has been proven to have the effect of resisting alcohol damage, but its mechanism is still unclear. In this study, the composition of mulberry ethanol extract (MBE) was identified by LC-MS/MS and the main components of MBE were ascertained by measuring. Gastric mucosal epithelial (GES-1) cells were used to elucidate the mechanism of MBE and rutin (the central part of MBE) helped protect against alcohol damage. The results revealed that phenolics accounted for the majority of MBE, accounting for 308.6 mg/g gallic acid equivalents and 108 substances were identified, including 37 flavonoids and 50 non-flavonoids. The treatment of 400 μg/mL MBE and 320 μM rutin reduced early cell apoptosis and the content of intracellular reactive oxygen species, malondialdehyde and increased glutathione. The qPCR results indicated that the MBE inhibits the expression of genes in the mitogen-activated protein kinase (MAPK) pathway, including p38, JNK, ERK and caspase-3; rutin inhibits the expression of p38 and caspase-3. Overall, MBE was able to reduce the oxidative stress of GES-1 cells and regulated apoptosis-related genes of the MAPK pathway. This study provides information for developing anti-ethanol injury drugs or functional foods.

Artocarpesin acts on human platelet aggregation through inhibition of cyclic nucleotides and MAPKs

The cardiovascular diseases (CVDs) are becoming a critical threat to our lives in these years. It is now widely accepted that platelets play an important role in cardiovascular disease as they have a fundamental role in thrombosis. Therefore, many drugs or natural substances have been developed to treat CVDs. Cudrania tricuspidata is a regional plant containing various constituents, such as xanthones, flavonoids, organic acids, and polysaccharides. It has been widely used in East Asia as an important ethnomedicine for the treatment of many diseases such as eczema, mumps, tuberculosis and acute arthritis. Therefore, we evaluated antiplatelet effects using artocarpesin isolated from C. tricuspidata. Confirmation of the antiplatelet function of artocarpesin was made according to the following analyzes. Artocarpesin inhibited collagen-induced human platelet aggregation, calcium mobilization, glycoprotein IIb/IIIa activation and thrombin-induced clot retraction through the regulation of associated signaling molecules. Artocarpesin increased the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and inositol 1, 4, 5-triphosphate receptor I (IP3RI). On the other hand, the phosphorylation of cytosolic phospholipase A2 (cPLA2), mitogen-activated protein kinases p38, JNK and phosphoinositide 3-kinase (PI3K)/Akt decreased. Thus, the study highlights that artocarpesin has an inhibitory effect on platelet activity and thrombus formation, showing its potential value in preventing platelet-induced cardiovascular disease.

Natural Phaeosphaeride A Derivatives Overcome Drug Resistance of Tumor Cells and Modulate Signaling Pathways.

In the present study, natural phaeosphaeride A (PPA) derivatives are synthesized. Anti-tumor studies are carried out on the PC3, K562, HCT-116, THP-1, MCF-7, A549, NCI-H929, Jurkat, and RPMI8226 tumor cell lines, and on the human embryonic kidney (HEK293) cell line. All the compounds synthesized turned out to have better efficacy than PPA towards the tumor cell lines listed. Among them, three compounds exhibited an ability to overcome the drug resistance of tumor cells associated with the overexpression of the P-glycoprotein by modulating the work of this transporter. Luminex xMAP technology was used to assess the effect of five synthesized compounds on the activation of intracellular kinase cascades in A431 cells. MILLIPLEX MAP Multi-Pathway Magnetic Bead 9-Plex was used, which allowed for the simultaneous detection of the following nine phosphorylated protein markers of the main intracellular signaling pathways: a universal transcription factor that controls the expression of immune-response genes, apoptosis and cell cycle NFκB (pS536); cAMP-dependent transcription factor (CREB (pS133); mitogen-activated kinase p38 (pT180/pY182); stress-activated protein kinase JNK (pT183/pY185); ribosomal SK; transcription factors STAT3 (pS727) and STAT5A/B (pY694/699); protein kinase B (Akt) (pS473); and kinase regulated by extracellular signals ERK1/2 (pT185/pY187). The effect of various concentrations of PPA derivatives on the cell culture was studied using xCelligence RTCA equipment. The compounds were found to modulate JNK, ERK1/2, and p38 signaling pathways. The set of activated kinase cascades suggests that oxidative stress is the main probable mechanism of the toxic action of PPA derivatives.

Effects of 3'-isovaleryl-4'-senecioylkhellactone from Peucedanum japonicum Thunberg on PMA-Stimulated Inflammatory Response in A549 Human Lung Epithelial Cells.

Peucedanum japonicum Thunberg (PJT) has been used in traditional medicine to treat colds, coughs, fevers, and other inflammatory diseases. The goal of this study was to investigate whether 3'-isovaleryl-4'-senecioylkhellactone (IVSK) from PJT has anti-inflammatory effects on lung epithelial cells. The anti-inflammatory effects of IVSK were evaluated using phorbol 12-myristate 13-acetate (PMA)-stimulated A549 cells and regular human lung epithelial cells as a reference. IVSK reduced the secretion of the inflammatory mediators interleukin (IL)-8 and monocyte chemoattractant protein-1 (MCP-1), and the mRNA expression of IL-6, IL-8, MCP-1, and IL-1β. Additionally, it inhibited the phosphorylation of IκB kinase (IKK), p65, Iκ-Bα, and mitogen-activated protein kinases (MAPKs) p38, JNK, and ERK in A549 cells stimulated with PMA. Moreover, the binding affinity of activator protein-1 (AP-1) and nuclear factor-κB (NF-κB) was significantly reduced in the luciferase assay, while nuclear translocation was markedly inhibited by IVSK in the immunocytochemistry. These findings indicate that IVSK can protect against inflammation through the AP-1 and NF-κB pathway and could possibly be used as a lead compound for the treatment of inflammatory lung diseases.

Hyperoside and Quercitrin in Houttuynia cordata Extract Attenuate UVB-Induced Human Keratinocyte Cell Damage and Oxidative Stress via Modulation of MAPKs and Akt Signaling Pathway.

Ultraviolet radiation is a major environmental harmful factor on human skin. In this paper, we investigate the potential mechanism of Houttuynia cordata extract on UVB-induced HaCaT keratinocyte cell death and inflammation. We found that Houttuynia cordata ethyl acetate extract fraction (HC-EA) protected against UVB-induced cell damage. The HPLC results indicate that quercitrin and hyperoside are the major polyphenolics in HC-EA and are responsible for providing protection against UVB-induced cell death. These responses were associated with the regulation of caspase-9 and caspase-3 activation, which rescued HaCaT cells from UVB-induced apoptosis. In addition, HC-EA, quercitrin, and hyperoside attenuated UVB-induced inflammatory mediators, including IL-6, IL-8, COX-2, and iNOS. Furthermore, the treatment of cells with HC-EA and its active compounds abolished intracellular ROS and increased levels of heme oxygenase-1 and superoxide dismutase. UVB-induced ROS production mediated Akt and mitogen activated protein kinases (MAPKs) pathways, including p38, ERK, and JNK. Our results show HC-EA, quercitrin, and hyperoside decreased UVB-induced p38 and JNK phosphorylation, while increasing ERK and Akt phosphorylation. MAPKs and Akt mediated cell survival and death were confirmed by specific inhibitors to Akt and MAPKs. Thus, HC-EA, which contains quercitrin and hyperoside, protected keratinocyte from UVB-induced oxidative damage and inflammation through the modulation of MAPKs and Akt signaling.

(E)-9-Octadecenoic Acid Ethyl Ester Derived from Lotus Seedpod Ameliorates Inflammatory Responses by Regulating MAPKs and NF-κB Signalling Pathways in LPS-Induced RAW264.7 Macrophages.

Inflammation is generally considered a key risk factor in the progress of several chronic diseases, such as arthritis, gastritis, and hepatitis. Natural products with anti-inflammatory ability have played a great role in the process of overcoming these inflammatory diseases. In this study, we evaluated the anti-inflammatory activities of ten natural compounds derived from lotus seedpod and discovered (E)-9-octadecenoic acid ethyl ester (E9OAEE) inhibited the production of nitric oxide (NO) optimally in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Furthermore, we explored the effects of E9OAEE on inflammatory responses and the underlying mechanisms in LPS-induced RAW264.7 macrophages. The results indicated that E9OAEE significantly suppressed the production of NO, prostaglandin E2 (PGE2), and tumour necrosis factor-α (TNFα) in a dose-dependent manner. The protein expression and mRNA levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) were inhibited by pretreatment of E9OAEE. Furthermore, E9OAEE restrained the phosphorylation of mitogen-activated protein kinase (MAPKs) family members, ERK, P38, and JNK stimulated by LPS-treated for 30 min and prevented the nuclear translocation of nuclear factor-kappa B (NF-κB) prompted by LPS-treated for 6 h in RAW264.7 macrophages. Taken together, we discovered an anti-inflammatory component from lotus seedpod and identified E9OAEE attenuated the inflammatory response in LPS-induced RAW264.7 macrophages probably by regulating the activation of MAPKs and NF-κB signalling pathways, which would provide some base for the development of new anti-inflammatory drugs.

New Alkoxy- Analogues of Epoxyeicosatrienoic Acids Attenuate Cisplatin Nephrotoxicity In Vitro via Reduction of Mitochondrial Dysfunction, Oxidative Stress, Mitogen-Activated Protein Kinase Signaling, and Caspase Activation.

The usage of cisplatin, a highly potent chemotherapeutic, is limited by its severe nephrotoxicity. Arachidonic acid (ARA)-derived epoxyeicosatrienoic acids (EETs) and soluble epoxide hydrolase (sEH) inhibitors were shown to ameliorate this dose-limiting side effect, but both approaches have some pharmacological limitations. Analogues of EETs are an alternative avenue with unique benefits, but the current series of analogues face concerns regarding their structure and mimetic functionality. Hence, in this study, regioisomeric mixtures of four new ARA alkyl ethers were synthesized, characterized, and assessed as EET analogues against the concentration- and time-dependent toxicities of cisplatin in porcine proximal tubular epithelial cells. All four ether groups displayed bioisostere activity, ranging from marginal for methoxy- (1), good for n-propoxy- (4), and excellent for ethoxy- (2) and i-propoxy- (3). Compounds 2 and 3 displayed cytoprotective effects comparable to that of an EET regioisomeric mixture (5) against high, acute cisplatin exposures but were more potent against low to moderate, chronic exposures. Compounds 2 and 3 (and 5) acted through stabilization of the mitochondrial transmembrane potential and attenuation of reactive oxygen species, leading to reduced phosphorylation of mitogen-activated protein kinases p38 and JNK and decreased activation of caspase-9 and caspase-3. This study demonstrates that alkoxy- groups are potent and more metabolically stable bioisostere alternatives to the epoxide within EETs that enable sEH-independent activity. It also illustrates the potential of ether-based mimics of EETs and other epoxy fatty acids as promising nephroprotective agents to tackle the clinically relevant side effect of cisplatin without compromising its antineoplastic function.

Amyloid peptide exerts a rapid induction of Dicer1 protein in neuron via reducing phosphorylation

A growing number of evidence suggests that altered microRNA network in the brain contributes to the risk of Alzheimer's disease(AD). Dicer1 is a type III riboendonuclease which cleaves pre-microRNA into functional microRNA. Reduction of Dicer1 or Dicer1 mutation has been involved in cancer, aging or age-related macular degeneration. Recently, we found a possible link between Dicer1 and AD. In particular, Dicer1 protein and Dicer1 mRNA is reduced in the hippocampus and the cortex of an animal model of AD and exposure to Aβ42 oligomer(AβO) longer than 6 h reduces the transcription of Dicer1 gene in neuron, via depletion of NF-E2-related factor-2. In this study, exposure to AβO at shorter time increased Dicer1 protein in neuron in a dose-dependent mode; but the mRNA level remained unaltered. Under this treatment regime,AβO reduced phosphorylation level of Dicer1 and of its binding partner, transactivation response element RNA-binding protein(TRBP). Addition of a JNK inhibitor,SP600125, or an ERK inhibitor,U0126, further increased Dicer1 protein compared to Aβo treatment alone, with simultaneaous reduction of phospho-Dicer1, but with different effects on phospho-TRBP. Finally, an inhibitor of calcineurin,FK506, further increased Dicer1 protein compared to Aβo treatment alone. Thus, phosphorylation of Dicer1 and TRBP was determined by mitogen activated protein kinases JNK,ERK, and protein phosphatase 2B(calcineurin) which together determined Dicer1 stability. In summary, reduced phosphorylation of Dicer1 accounted for the rapid induction of Dicer1 by AβO. This study highlights a novel way by which AβO regulates Dicer1.