JNK Activation Research Articles

A mismatch in the expression of cell surface molecules induces tissue-intrinsic defense against aberrant cells

Tissue-intrinsic error correction enables epithelial cells to detect abnormal neighboring cells and facilitate their removal from the tissue. One of these pathways, "interface surveillance," is triggered by cells with aberrant developmental and cell-fate-patterning pathways. It remains unknown which molecular mechanisms provide cells with the ability to compare fate between neighboring cells. We demonstrate that Drosophila imaginal discs express an array of cell surface molecules previously implicated in neuronal axon guidance processes. They include members of the Robo, Teneurin, Ephrin, Toll-like, or atypical cadherin families. Importantly, a mismatch in expression levels of these cell surface molecules between adjacent cells is sufficient to induce interface surveillance, indicating that differences in expression levels between neighboring cells, rather than their absolute expression levels, are crucial. Specifically, a mismatch in Robo2 and Robo3, but not Robo1, induces enrichment of actin, myosin II, and Ena/Vasp, as well as activation of JNK and apoptosis at clonal interfaces. Moreover, Robo2 can induce interface surveillance independently of its cytosolic domain and without the need for the Robo-ligand Slit. The expression of Robo2 and other cell surface molecules, such as Teneurins or the Ephrin receptor is regulated by fate-patterning pathways intrinsic and extrinsic to the wing disc, as well as by expression of oncogenic RasV12. Combined, we demonstrate that neighboring cells respond to a mismatch in surface code patterns mediated by specific transmembrane proteins and reveal a novel function for these cell surface proteins in cell fate recognition and removal of aberrant cells during development and homeostasis of epithelial tissues.

Tanshinone IIA induces ER stress and JNK activation to inhibit tumor growth and enhance anti-PD-1 immunotherapy in non-small cell lung cancer

BackgroundNon-small cell lung cancer (NSCLC) remains at the forefront of new cancer cases, and there is an urgent need to find new treatments or improve the efficacy of existing therapies. In addition to the application in the field of cerebrovascular diseases, recent studies have revealed that tanshinone IIA (Tan IIA) has anticancer activity in a variety of cancers. PurposeTo investigate the potential anticancer mechanism of Tan IIA and its impact on immunotherapy in NSCLC. MethodsCytotoxicity and colony formation assays were used to detect the Tan IIA inhibitory effect on NSCLC cells. This research clarified the mechanisms of Tan IIA in anti-tumor and programmed death-ligand 1 (PD-L1) regulation by using flow cytometry, transient transfection, western blotting and immunohistochemistry (IHC) methods. Besides, IHC was also used to analyze the nuclear factor of activated T cells 1 (NFAT2) expression in NSCLC clinical samples. Two animal models including xenograft mouse model and Lewis lung cancer model were used for evaluating tumor suppressive efficacy of Tan IIA. We also tested the efficacy of Tan IIA combined with programmed cell death protein 1 (PD-1) inhibitors in Lewis lung cancer model. ResultsTan IIA exhibited good NSCLC inhibitory effect which was accompanied by endoplasmic reticulum (ER) stress response and increasing Ca2+ levels. Moreover, Tan IIA could suppress the NFAT2/ Myc proto oncogene protein (c-Myc) signaling, and it also was able to control the Jun Proto-Oncogene(c-Jun)/PD-L1 axis in NSCLC cells through the c-Jun N-terminal kinase (JNK) pathway. High NFAT2 levels were potential factors for poor prognosis in NSCLC patients. Finally, animal experiments data showed a stronger immune activation phenotype, when we performed treatment of Tan IIA combined with PD-1 monoclonal antibody. ConclusionThe findings of our research suggested a novel mechanism for Tan IIA to inhibit NSCLC, which could exert anti-cancer effects through the JNK/NFAT2/c-Myc pathway. Furthermore, Tan IIA could regulate tumor PD-L1 levels and has the potential to improve the efficacy of PD-1 inhibitors.

Senescent cells and macrophages cooperate through a multi-kinase signaling network to promote intestinal transformation in Drosophila

Cellular senescence is a conserved biological process that plays a crucial and context-dependent role in cancer. The highly heterogeneous and dynamic nature of senescent cells and their small numbers in tissues make invivo mechanistic studies of senescence challenging. As a result, how multiple senescence-inducing signals are integrated invivo to drive senescence in only a small number of cells is unclear. Here, we identify cells that exhibit multiple features of senescence in a Drosophila model of intestinal transformation, which emerge in response to concurrent activation of AKT, JNK, and DNA damage signaling within transformed tissue. Eliminating senescent cells, genetically or by treatment with senolytic compounds, reduces overgrowth and improves survival. We find that senescent cells promote tumorigenesis by recruiting Drosophila macrophages to the transformed tissue, which results in non-autonomous activation of JNK signaling. These findings identify senescent cell-macrophage interactions as an important driver of epithelial transformation.

Puerarin Ameliorated PCOS through Preventing Mitochondrial Dysfunction Dependent on the Maintenance of Intracellular Calcium Homeostasis.

Polycystic ovarian syndrome (PCOS) is the major cause of infertility in reproductive women, but no universal drug is feasible. Although puerarin clinically treats cerebrovascular and cardiovascular diseases, its curative effect on PCOS remains elusive. The present study discovered that administration of puerarin restored estrous cycle of PCOS mice and diminished the number of cystic follicles with the concomitant recovery for circulating testosterone, LH and FSH levels, and LH/FSH ratio, indicating the therapeutic role of puerarin in PCOS. KEGG analysis of differential genes between PCOS and control revealed the enrichment in MAPK and calcium signaling pathway. Application of puerarin restricted the phosphorylation of ERK1/2 and JNK, whose activation neutralized the improvement of puerarin on the secretory function and apoptosis of ovarian granulosa cells (GCs). Meanwhile, puerarin alleviated the accumulation of cytosolic Ca2+ through restricting the opening of Ryr and Itpr channels, but this effectiveness was counteracted by the activatory ERK1/2 and JNK. Attenuation of cytosolic Ca2+ counteracted the antagonistic effects of ERK1/2 and JNK activation on puerarin's role in rescuing the calcineurin and Nfatc. Further analysis manifested that Mcu had been authenticated as a direct downstream target of Nfatc to mediate the amelioration of puerarin on mitochondrial Ca2+ uptake. Moreover, puerarin prevented the disorder of ATP content, mitochondrial membrane potential, and mitochondrial permeability transition pore opening through maintaining mitochondrial Ca2+ homeostasis. Collectively, puerarin might ameliorate the symptoms of PCOS mice through preventing mitochondrial dysfunction that is dependent on the maintenance of intracellular Ca2+ homeostasis after inactivation of ERK1/2 and JNK.

Xrp1 governs the stress response program to spliceosome dysfunction.

Co-transcriptional processing of nascent pre-mRNAs by the spliceosome is vital to regulating gene expression and maintaining genome integrity. Here, we show that the deficiency of functional U5 small nuclear ribonucleoprotein particles (snRNPs) in Drosophila imaginal cells causes extensive transcriptome remodeling and accumulation of highly mutagenic R-loops, triggering a robust stress response and cell cycle arrest. Despite compromised proliferative capacity, the U5 snRNP-deficient cells increased protein translation and cell size, causing intra-organ growth disbalance before being gradually eliminated via apoptosis. We identify the Xrp1-Irbp18 heterodimer as the primary driver of transcriptional and cellular stress program downstream of U5 snRNP malfunction. Knockdown of Xrp1 or Irbp18 in U5 snRNP-deficient cells attenuated JNK and p53 activity, restored normal cell cycle progression and growth, and inhibited cell death. Reducing Xrp1-Irbp18, however, did not rescue the splicing defects, highlighting the requirement of accurate splicing for cellular and tissue homeostasis. Our work provides novel insights into the crosstalk between splicing and the DNA damage response and defines the Xrp1-Irbp18 heterodimer as a critical sensor of spliceosome malfunction and mediator of the stress-induced cellular senescence program.

Auraptene inhibits migration, invasion and metastatic behavior of human malignant glioblastoma cells: An in vitro and in silico study.

The present work examined the anti-metastatic effects of auraptene and their underlying mechanisms of action in U87 Glioblastoma multiforme (GBM) cells. To test the hypothesis, cell culture, Matrigel invasion assay, scratch wound healing assay, gelatin zymography assay, qRT-PCR, and western blot experiments were conducted. At sublethal concentrations of 12.5 and 25 µg/ml, auraptene exhibited a significant reduction in cell invasion and migration of U87 cells, as assessed using scratch wound healing and Transwell tests, respectively. The qRT-PCR and zymography experiments demonstrated a significant decrease in both mRNA expression and activities of MMP-2 and MMP-9 following auraptene treatment. Western blot analysis also showed that MMP-2 protein level and phosphorylation of metastasis-related proteins (p-JNK and p-mTOR) decreased in auraptene-treated cells. Molecular docking studies consistently demonstrated that auraptene exhibits a significant affinity towards MMP-2/-9, the ATP binding site of mTOR and JNK1/2/3. Auraptene inhibited the migration and invasion of GBM cells. This inhibitory effect was induced by modulating specific mechanisms, including suppressing MMPs, JNK, and mTOR activities.

Asynchronous Pattern of MAPKs' Activity during Aging of Different Tissues and of Distinct Types of Skeletal Muscle.

The MAPK p38α was proposed to be a prominent promoter of skeletal muscle aging. The skeletal muscle tissue is composed of various muscle types, and it is not known if p38α is associated with aging in all of them. It is also not known if p38α is associated with aging of other tissues. JNK and ERK were also proposed to be associated with aging of several tissues. Nevertheless, the pattern of p38α, JNK, and ERK activity during aging was not documented. Here, we documented the levels of phosphorylated/active p38α, Erk1/2, and JNKs in several organs as well as the soleus, tibialis anterior, quadriceps, gastrocnemius, and EDL muscles of 1-, 3-, 6-, 13-, 18-, and 24-month-old mice. We report that in most tissues and skeletal muscles, the MAPKs' activity does not change in the course of aging. In most tissues and muscles, p38α is in fact active at younger ages. The quadriceps and the lungs are exceptions, where p38α is significantly active only in mice 13 months old or older. Curiously, levels of active JNK and ERKs are also elevated in aged lungs and quadriceps. RNA-seq analysis of the quadriceps during aging revealed downregulation of proteins related to the extra-cellular matrix (ECM) and ERK signaling. A panel of mRNAs encoding cell cycle inhibitors and senescence-associated proteins, considered to be aging markers, was not found to be elevated. It seems that the pattern of MAPKs' activation in aging, as well as expression of known 'aging' components, are tissue- and muscle type-specific, supporting a notion that the process of aging is tissue- and even cell-specific.

DUSP4 maintains the survival and LSD1 protein stability in esophageal squamous cell carcinoma cells by inhibiting JNK signaling-dependent autophagy.

DUSP4 is a biomarker of esophageal squamous cell carcinoma (ESCC), which is responsible for the prognosis in ESCC. However, the underlying mechanism of DUSP4-regulated ESCC carcinogenesis is unknown. As a negative regulator of JNK, DUSP4 can inhibit autophagy, which contributes to tumorigenesis. This study aimed to explore the role of autophagy in DUSP4-regulated ESCC carcinogenesis. Our results showed that DUSP4 overexpression inhibited autophagy and promoted LSD1 protein expression in ESCC cells, while DUSP4 silencing showed the opposite effects. However, DUSP4 overexpression and silencing did not affect LSD1 mRNA expression. But the regulatory ability of DUSP4 overexpression on autophagy, death level, and LSD1 protein was reversed by rapamycin. In addition, DUSP4 overexpression inhibited JNK and Bcl2 phosphorylation and the dissociation of Bcl2-Beclin1 complex, while DUSP4 silencing promoted JNK and Bcl2 phosphorylation. Moreover, the regulatory ability of DUSP4 overexpression on autophagy, death, and LSD1 protein was reversed by JNK activator anisomycin. The xenograft assays also showed that DUSP4 overexpression-promoted ESCC tumor growth in vivo and LC3II and LSD1 protein expression in tumor tissues were reversed by rapamycin or anisomycin. Overall, DUSP4 inhibits Bcl2-Beclin1-autophagy signal transduction through the negative regulation of JNK, thus suppressing autophagic death and the autophagic degradation of LSD1 in ESCC, by which DUSP4 promotes ESCC carcinogenesis.

JNK inhibition enhances cell-cell adhesion impaired by desmoglein3 gene disruption in keratinocytes.

c-Jun NH2-terminal protein kinase (JNK) and p38 are stress-activated mitogen-activated protein kinases (MAPK) that are phosphorylated by various stimuli. It has been reported that the loss of desmoglein (DSG) 3, a desmosomal transmembrane core molecule, in keratinocytes impairs cell-cell adhesion accompanied by p38 MAPK activation. To understand the biological role of DSG3 in desmosomes and its relationship with stress-activated MAPKs, we established DSG3 knockout keratinocytes (KO cells). Wild-type cells showed a linear localization of DSG1 to cell-cell contacts, whereas KO cells showed a remarkable reduction despite the increased protein levels of DSG1. Cell-cell adhesion in KO cells was impaired over time, as demonstrated by dispase-based dissociation assays. The linear localization of DSG1 to cell-cell contacts and the strength of cell-cell adhesion were promoted by the pharmacological inhibition of JNK. Conversely, pharmacological activation of JNK, but not p38 MAPK, in wild-type cells reduced the linear localization of DSG1 in cell-cell contacts. Our data indicate that DSG1 and DSG2 in KO cells cannot compensate for the attenuation of cell-cell adhesion strength caused by DSG3 deficiency and that JNK inhibition restores the strength of cell-cell adhesion by increasing the linear localization of DSG1 in cell-cell contacts in KO cells. Inhibition of JNK signaling may improve cell-cell adhesion in diseases in which DSG3 expression is impaired.

Abstract A107: MAPK signaling is a conserved mechanism explaining phenotypic heterogeneity across diverse drivers of epithelial-mesenchymal transition in pancreas cancer

Abstract Epithelial-mesenchymal transition (EMT) is a developmental process that is aberrantly activated in cancers such as pancreatic ductal adenocarcinoma (PDAC) to promote disease progression and chemoresistance. EMT occurs heterogeneously among PDAC ductal cells, which frustrates efforts to identify the underlying signaling regulatory mechanisms. We hypothesize that cell-to-cell variation in the activities of specific signaling pathways explains EMT heterogeneity. To test this, we developed a workflow integrating: 1) iterative indirect immunofluorescence imaging (4i) to quantify the activities of up to seven purported EMT-regulating pathways with single-cell resolution and 2) a multivariate mutual information computational model to predict the pathways that are most informative of the EMT phenotype. In cultured PDAC cells, EMT was induced by treating cells with growth factors present in the tumor microenvironment (hepatocyte growth factor, epidermal growth factor, transforming growth factor β1, or two combinations) or with chemotherapeutics (gemcitabine or 5-fluorouracil). EMT phenotypic markers and signaling pathway proxies were assessed daily for up to 96 hr. A mutual information analysis of the aggregated data identified ERK as the most important signaling node explaining EMT heterogeneity across the diverse set of agonists investigated. Kinase inhibition and siRNA studies confirmed the implied role of ERK but also revealed a compensatory, EMT-driving JNK activation in the context of MEK inhibition that explains a cooperative effect of simultaneous MEK and JNK inhibition on EMT antagonism. Importantly, a model based on cell population-level measurements nominated JNK as more informative than ERK for determining EMT state in response to growth factors. We are implementing this approach in vivo using pancreas cancer tissue sections to determine generalizability of these findings in different microenvironmental contexts. Overall, our results demonstrate the pervasive importance of ERK for diverse drivers of EMT and the need to account for the effects of heterogeneous signaling pathway activation in the determination of EMT. Citation Format: Michelle C. Barbeau, Matthew J. Lazzara. MAPK signaling is a conserved mechanism explaining phenotypic heterogeneity across diverse drivers of epithelial-mesenchymal transition in pancreas cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A107.

Palmitate induces integrated stress response and lipoapoptosis in trophoblasts

Maternal obesity increases the risk of childhood obesity and programs the offspring to develop metabolic syndrome later in their life. Palmitate is the predominant saturated free fatty acid (FFA) that is transported across the placenta to the fetus. We have recently shown that saturated FFA in the maternal circulation as a result of increased adipose tissue lipolysis in third trimester of pregnancy induces trophoblast lipoapoptosis. Here, we hypothesized that palmitate induces integrated stress response by activating mitogen-activated protein kinases (MAPKs), endoplasmic reticulum (ER) stress and granular stress and lipoapoptosis in trophoblasts. Choriocarcinoma-derived third-trimester placental trophoblast-like cells (JEG-3 and JAR) referred as trophoblasts were exposed to various concentrations of palmitate (PA). Apoptosis was assessed by nuclear morphological changes and caspase 3/7 activity. Immunoblot and immunofluorescence analysis was performed to measure the activation of MAPKs, ER stress and granular stress response pathways. Trophoblasts exposed to pathophysiological concentrations of PA showed a concentration-dependent increase in trophoblast lipoapoptosis. PA induces a caspase-dependent trophoblast lipoapoptosis. Further, PA induces MAPK activation (JNK and ERK) via phosphorylation, and activation of ER stress as evidenced by an increased phosphorylation eIF2α & IRE1α. PA also induces the activation of stress granules formation. Two pro-apoptotic transcriptional mediators of PA-induced trophoblast lipoapoptosis, CHOP and FoxO3 have increased nuclear translocation. Mechanistically, PA-induced JNK is critical for trophoblast lipoapoptosis. However, PA-induced activation of ERK and stress granule formation were shown to be cell survival signals to combat subcellular stress due to PA exposure. In conclusion, PA induces the activation of integrated stress responses, among which small molecule inhibition of JNK demonstrated that activation of JNK is critical for PA-induced trophoblast lipoapoptosis and small molecule activation of stress granule formation significantly prevents PA-induced trophoblast lipoapoptosis.

A novel polysaccharide isolated from Coriolus versicolor polarizes M2 macrophages into an M1 phenotype and reversesits immunosuppressive effect on tumor microenvironment

Converting M2 macrophages into an M1 phenotype in the tumor microenvironment, provides a new direction for tumor treatment. Here, we further report CVPW-1, a new polysaccharide of 1.03 × 106 Da that was isolated from Coriolus versicolor. Its monosaccharide was composed of mannose, glucose, and galactose at a ratio of 1.00:8.73:1.68. The backbone of CVPW-1 was composed of (1 → 3)-linked α-D-Glcp residues and (1 → 3,6)-linked α-D-Glcp residues that branched at O-6. The branch consisted of (1 → 6)-linked α-D-Glcp residues and (1 → 4)-linked α-D-Glap, and some branches were terminated with (1→)-linked β-D-Manp residues according to the results of HPLC, FT-IR, GC–MS, 1D and 2D NMR. Meanwhile, CVPW-1 could polarize M2 macrophages to M1 phenotypein vitro by binding to TLR4 and inducing the activation of Akt, JNK and NF-κB. This process involved reversing the functional inhibition of CD8+ T lymphocytes by inhibiting the expression of TREM2 in M2 macrophages. The in vivo experiments showed that oral administration of CVPW-1 could inhibit the growth of tumor in mice and polarize TAMs to M1 phenotype. Thus, the novel polysaccharide CVPW-1 from Coriolus versicolor might activate a variety of immune cells and then play an anti-tumor role. These results demonstrated that CVPW-1 could be developed as a potential immuno-oncology treatment reagent.

S1PR1 inhibition induces proapoptotic signaling in T cells and limits humoral responses within lymph nodes.

Effective immunity requires a large, diverse naive T cell repertoire circulating among lymphoid organs in search of antigen. Sphingosine 1-phosphate (S1P) and its receptor S1PR1 contribute by both directing T cell migration and supporting T cell survival. Here, we addressed how S1P enables T cell survival and the implications for patients treated with S1PR1 antagonists. We found that S1PR1 limited apoptosis by maintaining the appropriate balance of BCL2 family members via restraint of JNK activity. Interestingly, the same residues of S1PR1 that enable receptor internalization were required to prevent this proapoptotic cascade. Findings in mice were recapitulated in ulcerative colitis patients treated with the S1PR1 antagonist ozanimod, and the loss of naive T cells limited B cell responses. Our findings highlighted an effect of S1PR1 antagonists on the ability to mount immune responses within lymph nodes, beyond their effect on lymph node egress, and suggested both limitations and additional uses of this important class of drugs.

Diallyl trisulfide (DATS) protects cardiac cells against advanced glycation end-product-induced apoptosis by enhancing FoxO3A-dependent upregulation of miRNA-210

Diabetic cardiomyopathy is a common complication of diabetes, resulting in cardiac hypertrophy and heart failure associated with excessive reactive oxygen species and mitochondria-mediated apoptosis generation. Mitogen-activated protein kinase-c-Jun N-terminal kinase (MAPK-JNK), regulated by microRNA (miR)-210, affects mitochondrial function and is activated by advanced glycation end-products (AGE) in cardiac cells. Diallyl trisulfide (DATS), an antioxidant in garlic oil, inhibits stress-induced cardiac apoptosis. This study examined whether DATS enhances miR-210 expression to attenuate cardiac apoptosis. We investigated the DATS-mediated attenuation mechanism of AGE-enhanced cardiac apoptosis by modulating miR-210 and its upstream transcriptional regulator, FoxO3a. We found FoxO3a binding sites in the miR-210 promoter region. Our results indicated that DATS treatment inhibited AGE-induced JNK activation, phosphoprotein c-Jun nuclear transactivation, and cardiac apoptosis and reversed the AGE-induced reduction in cardiac miR-210 levels. The luciferase activity after DATS treatment was significantly lower than that of the control and was reversed following AGE treatment. We also showed that FoxO3a, upregulated by DATS treatment, may bind to the miR-210 promoter to enhance its expression and downregulates JNK expression to attenuate AGE-induced cardiac apoptosis. Oral administration of DATS enhanced FoxO3a expression in the heart and reduced diabetes-induced heart apoptosis. Our findings indicate that DATS mediates AGE-induced cardiac cell apoptosis attenuation by promoting FoxO3a nuclear transactivation to enhance miR-210 expression and regulate JNK activation. Our results suggest that DATS can be used as a cardioprotective agent, and miR-210 is a critical regulator in inhibiting diabetic cardiomyopathy.

C-Jun N-terminal Kinase (JNK), p38, and Caspases: Promising Therapeutic Targets for the Regulation of Apoptosis in Cancer Cells by Phytochemicals

Abstract: Carcinogenesis is a process in which uncontrolled cell proliferation forms preneoplastic nodules which precede the appearance of cancer. In normal cells, growth and proliferation are regulated by certain growth and hormonal stimulation, while mutational alterations in these signals render the cells independent and resistant to these signals. In cancer, the critical homeostatic balance between cell growth and apoptosis is lost and the cells continue to survive beyond their normal life span. The activation of c-Jun N-terminal kinase (JNK), p38 and caspases are involved in potential proapoptotic signaling pathways. JNK, p38 MAPK pathway and caspases play a crucial role in the control of apoptosis in response to stress. The most recent and up-to-date literature was evaluated in this study, which describes the role of JNK, p38 MAPK pathway and caspases as therapeutic target in cancer. Chemotherapy uses drugs that are cytotoxic to highly proliferating tumor cells but also kills the non-tumor rapidly proliferating cells in the hair, skin and gastrointestinal tract epithelium, thereby accounting the side effects of these types of treatments. Recently, chemopreventive modalities derived from phytoconstituents present in plants provide a broad-spectrum strategy to overcome the incidence of cancer. Non-toxic, safe and affordable bioavailabilities of chemopreventive agents provide credence support in the field of cancer research compared to conventional therapies that cause serious consequences. Chemoprevention envisages the basic mechanisms like modulating the activity of xenobiotic-metabolizing enzymes, induction of apoptosis, immune system activation, suppressing angiogenesis and the formation of metastasis, antioxidant and anti-inflammatory properties. The present review highlighted the role of phytoconstituents derived from food, vegetables and medicinal plants in the induction of apoptosis in cancer cells, which in turn is mediated by the activation of JNK, p38 MAPK pathways, and caspases.

Identification of chalcone analogues as anti-inflammatory agents through the regulation of NF-κB and JNK activation.

To develop new anti-inflammatory agents with improved pharmaceutical profiles, a series of chalcone analogues were designed and synthesized. In vitro anti-inflammatory activity of these compounds was evaluated by screening their inhibitory effects on NO production in RAW264.7 cell lines. The most promising compounds 3h and 3l were selected for further investigation by assessment of their dose-dependent inhibitory activity against cytokines such as TNF-α, IL-1β, and IL-6 and PGE2 release. The further study also indicated that 3h and 3l could significantly suppress the expression of iNOS and COX-2 through the NF-κB/JNK signaling pathway. Furthermore, compounds 3h and 3l could also remarkably inhibit the mRNA expression of inflammation-related genes. Meanwhile, 3h could also down-regulate ROS production. Docking simulation was conducted to position compounds 3h and 3l into the iNOS binding site to predict the probable binding mode. In conclusion, this series of chalcone analogues with reasonable drug-likeness obtained via in silico rapid prediction can be used as promising lead candidates.

Hexane insoluble fraction from purple rice extract improves steatohepatitis and fibrosis via inhibition of NF-κB and JNK signaling.

Nonalcoholic fatty liver disease (NAFLD) is fatty liver mainly related to metabolic syndrome. NAFLD with inflammation and hepatocellular damage is defined as nonalcoholic steatohepatitis (NASH), which can progress to cirrhosis and hepatocellular carcinoma. We have previously reported that a hexane insoluble fraction from an anthocyanin-rich purple rice ethanolic extract (PRE-HIF) can suppress prostate carcinogenesis. However, the extract's effect on NASH has not yet been established. In the present study, we investigated the chemopreventive effect of a PRE-HIF on NASH and liver fibrosis using a connexin 32 (Cx32) dominant negative transgenic (Cx32ΔTg) rat NASH model. Seven-week-old male Cx32ΔTg rats were fed a control diet, a high-fat diet (HFD), or an HFD with 1% PRE-HIF and intraperitoneal administration of dimethylnitrosamine for 17 weeks. Histological findings of NASH such as fat deposition, lobular inflammation, hepatocyte ballooning injury, and bridging fibrosis were observed in the HFD group but not in the control group, and all histological parameters were significantly improved by PRE-HIF treatment. Corresponding to the histological changes, increased expression of inflammatory cytokine mRNAs (TNF-α, IL-6, IL-18, IFN-γ, IL-1β, TGF-β1, TIMP1, TIMP2, COL1A1), along with and activation of nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) signaling were observed in the HFD group, which was significantly decreased by PRE-HIF. The number and area of hepatic precancerous glutathione S-transferase placental form-positive foci tended to be decreased by PRE-HIF. These results indicate that intake of purple rice as a dietary supplement may reduce steatohepatitis, liver injury, and fibrosis in NASH by inactivation of NF-κB or JNK.

Cytokine modification by the RNA regulatory protein TFL

We found a novel gene, named "transformed follicular lymphoma" (TFL), in a patient who developed diffuse large B-cell lymphoma from follicular lymphoma. TFL modulates several cytokines and chemokines by binding their 3'UTR region of mRNA with its unique RNase motif. TFL is part of a family called zinc finger CCCH-type containing 12A-D. Due to its unique RNase motif, the TFL family is also called regulatory RNase (Regnase 1-4). TFL is expressed in lymphoid tissue and is upregulated by an inflammatory response, contributing to autoimmune diseases such as multiple sclerosis via IL-17 in CNS and worsening inflammation (cachexia) due to lymphoma progression through CXCL-13. Loss of TFL expression is reported to be a valuable biomarker for various cancers, including lung adenocarcinoma, endometrial cancer, and possibly lymphoma. In addition to its mRNA modulation function, Regnase1 is known to have deubiquitinase activity for TRAF2, 3, and 6, attenuating JNK and NFκB activity, and TFL captures and transports naked nonvesicular extracellular mRNA of IL-1β to the nucleus, enhancing the tumor-killing activity in NK cells. Based on its potential to modulate inflammation, TFL could be a future treatment target for autoimmune diseases and cancer.

Sebacic acid, a royal jelly-containing fatty acid, decreases LPS-induced IL-6 mRNA expression in differentiated human THP-1 macrophage-like cells.

Macrophages produce many inflammatory mediators, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), in innate immune responses. However, excess production of these mediators by activated macrophages triggers deleterious effects, leading to disorders associated with inflammation. Royal jelly (RJ), a milky-white substance secreted by worker bees, contains unique fatty acids, including 10-hydroxy-2-decenoic acid (10H2DA) and sebacic acid (SA). 10H2DA has been reported to have various biological functions, such as anti-inflammation. However, the anti-inflammatory effect of SA is not fully understood. In this study, we investigated the effects of SA on lipopolysaccharide (LPS)-induced cytokine expression using differentiated human THP-1 macrophage-like cells. SA dose-dependently decreased LPS-induced mRNA expression of IL-6, but not TNF-α and IL-1β. SA suppressed the phosphorylation of signal transducers and activators of transcription 1 (STAT1) and STAT3, but hardly affected the activation of JNK, p38, or NF-κB. In addition, SA decreased LPS-induced interferon-β (IFN-β) expression, and the addition of IFN-β restored the inhibition by SA of LPS-induced STAT activation and IL-6 expression. Furthermore, SA suppressed LPS-induced nuclear translocation of interferon regulatory factor 3 (IRF3), a transcription factor responsible for IFN-β expression. Taken together, we conclude that SA selectively decreases LPS-induced expression of IL-6 mRNA through inhibition of the IRF3/IFN-β/STAT axis.

Clinacanthus nutans leaf extract reduces pancreatic β-cell apoptosis by inhibiting JNK activation and modulating oxidative stress and inflammation in streptozotocin-induced diabetic rats.

Controlling apoptosis induced by oxidative stress in pancreatic β-cells provides promising strategies for preventing and treating diabetes. Clinacanthus nutans leaves possess bioactive constituents with potential antioxidant and anti-diabetic properties. This study aimed to investigate the molecular mechanisms by which C. nutans extract protects pancreatic β-cells from apoptotic damage in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in male Wistar rats by intraperitoneal injection of 45 mg/kg STZ, followed by 28 days of treatment with C. nutans leaf extract and Glibenclamide as the standard drug. At the end of the study, blood samples were collected to measure glucose levels, oxidative stress markers, and inflammation. Pancreatic tissue was stained immunohistochemically to detect c-Jun N-terminal kinase (JNK) and Caspase-3 expression. The administration of C. nutans leaf extract to diabetic rats significantly reduced fasting blood glucose, malondialdehyde, and tumor necrosis factor-α levels, while concurrently enhancing the activity of superoxide dismutase. The immunohistochemical studies revealed a decrease in the expression of JNK and caspase-3 in the pancreatic islets of diabetic rats. Clinacanthus nutans exhibits the potential to protect pancreatic β-cells from apoptosis by suppressing oxidative stress and inflammation.