c-Jun N-terminal Kinase Signaling Research Articles

AKT regulates IL-1β-induced proliferation and activation of hepatic stellate cells

Background: Activated hepatic stellate cells (HSCs) are closely involved in the initiation, perpetuation, and resolution of liver fibrosis. Pro-inflammatory cytokine levels are positively correlated with the transition from liver injury to fibrogenesis and contribute to HSC pathophysiology in liver fibrosis. Methods: In this study, we investigated the effect of the pro-inflammatory cytokine interleukin (IL)-1β on the proliferation and signaling pathways involved in fibrogenesis in LX-2 cells, an HSC cell line, using western blotting and cell proliferation assays. Results: IL-1β increased the proliferation rate and α-smooth muscle actin (SMA) expression of LX-2 cells in a dose-dependent manner. Within 1 h after IL-1β treatment, c-Jun N-terminal kinase (JNK), p38, and nuclear factor-κB (NF-κB) signaling was activated in LX-2 cells. Subsequently, protein kinase B (AKT) phosphorylation and an increase in α- SMA expression were observed in LX-2 cells. Each inhibitor of JNK, p38, or NF-κB decreased cell proliferation, AKT phosphorylation, and α-SMA expression in IL-1β-treated LX-2 cells. Conclusion: These results indicate that JNK, p38, and NF-κB signals converge at AKT phosphorylation, leading to LX-2 activation by IL-1β. Therefore, the AKT signaling pathway can be used as a target for alleviating liver fibrosis by the inflammatory cytokine IL-1β.

Signaling interactions among neurons impact cell fitness and death in Alzheimer's disease.

The pathology of Alzheimer's disease involves a long preclinical period, where the characteristic clinical symptoms of the changes in the brain are undetectable. During the preclinical period, homeostatic mechanisms may help prevent widespread cell death. Evidence has pointed towards selective cell death of diseased neurons playing a potentially protective role. As the disease progresses, dysregulation of signaling pathways that govern cell death contributes to neurodegeneration. Aberrant activation of the c-Jun N-terminal kinase pathway has been established in human and animal models of Alzheimer's disease caused by amyloid-beta 42- or tau-mediated neurodegeneration. Clonal mosaic studies in Drosophila that examine amyloid-beta 42 in a subset of neurons suggest complex interplay between amyloid-beta 42-expressing and wild-type cells. This review examines the role of c-Jun N-terminal kinase signaling in the context of cell competition and short-range signaling interactions between amyloid-beta 42-expressing and wild-type neurons. Cell competition is a conserved phenomenon regulating tissue integrity by assessing the fitness of cells relative to their neighbors and eliminating suboptimal cells. Somatic clones of amyloid-beta 42 that juxtapose genetically distinct neuronal cell populations show promise for studying neurodegeneration. Generating genetic mosaics with labeled clones of amyloid-beta 42- or tau-expressing and wild-type neurons will allow us to understand how short-range signaling alterations trigger cell death in neurons and thereby contribute to the progression of Alzheimer's disease. These approaches have the potential to uncover biomarkers for early Alzheimer's disease detection and new therapeutic targets for intervention.

Possible Implication of Nrf2, PPAR-γ and MAPKs Signaling in the Protective Role of Mangiferin against Renal Ischemia/Reperfusion in Rats.

Mangiferin (Mang) is a known glucosylxanthone that has proven its shielding effect against ischemia/reperfusion (Is/R). However, its full underlying mechanistic perspective against renal Is/R induced lesions is not fully revealed. Consequently, the purpose of this study is to track further non-investigated modulatory signals of Mang against the renal Is/R model involving nuclear factor erythroid 2-related factor (Nrf)2/heme oxygenase (HO)-1, peroxisome proliferator-activated receptor (PPAR)-γ/nuclear factor (NF)-κB, p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) signaling. To ratify our aim, Mang was administrated (20 mg/kg, i.p for seven days) before the induction of bilateral Is/R. Mechanistic maneuver revealed that Mang balanced oxidative state via increasing the expression of the antioxidant Nrf2/HO-1 cue with subsequent enhancement of GSH besides MDA lessening. Additionally, Mang enhanced PPAR-γ mRNA expression and declined p-p38 MAPK and p-JNK expression with concomitant NF-κB downsizing leading to iNOS/NOx and TNF-α rebating. Furthermore, the Mang anti-apoptotic trait was affirmed by enriching Bcl-2 expression as well as decreasing Bax and caspase-3 expression. All these potentials were in the line with the molecular docking results and the improved histopathological findings and renal function biomarkers. Consequently, Mang provided plausible protective mechanisms against renal Is/R-related events, possibly by amending oxidative status, inflammatory mediators, and apoptotic cell death through the involvement of Nrf2, PPAR-γ, MAPK, JNK, and NF-κB signaling.

Nobiletin inhibits breast cancer cell migration and invasion by suppressing the IL-6-induced ERK-STAT and JNK-c-JUN pathways

BackgroundBreast cancer is one of the most common cancers in women, affecting more than 2 million women worldwide annually. However, effective treatments for breast cancer are limited. Nobiletin is a flavonoid present in the dried mature pericarp of mandarin orange (Citrus reticulata Blanco), which is used to prepare Citri Renetulatae Pericarpium and can inhibit tumour growth and progression according to modern pharmacological studies. However, whether nobiletin exhibits an antimetastatic role in breast cancer and its potential mechanism need to be further investigated. PurposeThis study aims to evaluate the inhibitory effect of nobiletin on breast cancer and to elucidate potential mechanisms against invasion and migration. MethodsCell viability was determined by cell counting kit-8 and colony formation assays. Wound healing and Boyden chamber assays detected cancer cell migration and invasion capabilities. Immunoblotting and qPCR were applied to determine the protein and mRNA expression levels of extracellular signal-regulated kinases (ERK) and the c-Jun N-terminal kinase (JNK) signalling pathways. Molecular docking was used to assess the degree of nobiletin binding to phosphatidylinositol 3-kinase (PI3K). Xenografts and liver metastases were constructed in BALB/c nude mice to evaluate the anticancer effect of nobiletin in vivo. H&E staining and immunohistochemistry were used to detect proliferation and the expression of related proteins. ResultsNobiletin induced cell death in a concentration- and time-dependent manner and possessed anti-invasion and anti-migration effects on MCF-7 and T47D cells by suppressing the interleukin-6-induced ERK and JNK signalling pathways. In addition, nobiletin docked with the binding site of PI3K, and the binding score was -8.0 kcal/mol. Furthermore, the inhibition of breast cancer growth and metastasis by nobiletin was demonstrated by constructing xenografts and liver metastases in vivo. ConclusionNobiletin inhibited liver metastasis of breast cancer by downregulating the ERK-STAT and JNK-c-JUN pathways, and its safety and efficacy were verified, indicating the potential of nobiletin as an anticancer agent.

C-Jun regulates flotillin 2 transcription to benefit viral accumulation in insect vectors

The c-Jun N-terminal kinase (JNK) signaling pathway plays a critical role in viral infection in host cells. In addition to triggering immune reactions against pathogens, the JNK signaling pathway has also been found to benefit viral infection. Our previous work showed that JNK activation facilitated rice stripe virus (RSV) accumulation in the insect vector small brown planthopper, but the underlying mechanisms remain elusive. Here, we revealed a link between JNK activation and the transcriptional upregulation of the plasma membrane protein flotillin 2, which mediates RSV cell entry. c-Jun, a downstream substrate of JNKs, was identified as a transcription factor that targets the promoter of flotillin 2 at three binding sites. Phosphorylated c-Jun, especially at the serine 63 site, promoted the transcriptional activity of c-Jun on flotillin 2. JNK activation or inhibition affected c-Jun phosphorylation status and flotillin 2 expression. In the midguts of planthoppers, RSV infection significantly increased flotillin 2 expression and the phosphorylation level of JNKs and c-Jun. Manipulation of JNK status impacted viral acquisition in midgut cells. These findings reveal a new regulatory mechanism of the JNK signaling pathway and shed light on the virus-supportive effect of this pathway.

Amentoflavone-Enriched Selaginella rossii Protects against Ultraviolet- and Oxidative Stress-Induced Aging in Skin Cells.

Selaginellaceae plants are used in cosmetics to limit skin aging. This study is the first to investigate the anti-aging effects of Selaginella rossii (SR) on ultraviolet B (UVB)- and oxidative stress-induced skin cells. The 95% ethanol extract of Selaginella rossii (SR95E) contained much higher amounts of amentoflavone (AMF), an active compound, than other Selaginellaceae plants and was more effective in inhibiting matrix metalloproteinase (MMP)-1 expression in CCD-986sk fibroblasts. SR95E significantly decreased UVB-induced MMP-1, MMP-2, MMP-3 and MMP-9 expression and enhanced procollagen type I C-peptide content and mRNA expression of collagen type I alpha (COL1A)1 and COL1A2 in CCD-986sk fibroblasts. In HaCaT keratinocytes, SR95E treatment also dose-dependently decreased UVB-induced MMP-1 concentration and MMP-1, MMP-2, MMP-3 and MMP-9 mRNA expression. Moreover, SR95E treatment markedly inhibited UVB-induced c-Jun N-terminal kinase and p38 mitogen-activated protein kinase signaling and nuclear factor kappa-B signaling in HaCaT cells. Furthermore, SR95E and AMF markedly regulated the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced expression of cellular senescence-related markers, including p16, p21 and LMNB1, in HaCaT cells. Overall, this study indicates that SR may have potential as a functional material on preventing UVB- and AAPH-induced skin aging and wrinkles.

Protective effect of astragalus membranaceus and its bioactive compounds against the intestinal inflammation in Drosophila.

Inflammatory bowel disease (IBD) is characterized by chronic and relapsing intestinal inflammation, which currently lacks safe and effective medicines. Astragalus membranaceus (AM), also named Huangqi, is one of the most commonly used fundamental herbs in China. Here, we aimed to investigate mechanism and bioactive compounds of AM on treating sodium dodecyl sulfate (SDS)- induced colitis in Drosophila flies. Our data showed that AM extract (AME) supplementation had no toxic effect in flies, and protected flies against SDS-induced lifespan shortening, intestinal morphological damage, and colon length shortening. Moreover, AME supplementation remarkably rescued SDS-induced intestinal stem cell (ISC) overproliferation and increased reactive oxygen species (ROS) level in the intestine. Mechanistically, AME remarkably rescued the altered expression levels of genes and proteins in c-Jun N-terminal kinase (JNK) and JAK-STAT signaling pathways induced by SDS in gut. Additionally, formononetin, isoliquiritigenin, isorhamnetin, astragaloside I, astragaloside III, vanillic acid, and caffeic acid in AM had protection against SDS-induced inflammatory damage in flies. Taken together, AME could ameliorate the intestinal inflammation partially by suppressing oxidative stress-associated JNK signaling and JAK-STAT signaling pathways. AME may provide a theoretical basis for natural medicine toward treating intestinal inflammatory disease in human.

Arsenic trioxide promotes ERK1/2-mediated phosphorylation and degradation of BIMEL to attenuate apoptosis in BEAS-2B cells

Inorganic arsenic is highly toxic, widely distributed in the human environment and may result in multisystem diseases and several types of cancers. The BCL-2-interacting mediator of cell death protein (BIM) is a key modulator of the intrinsic apoptosis pathway. Interestingly, in the present study, we found that arsenic trioxide (As2O3) decreased BIMEL levels in human bronchial epithelial cell line BEAS-2B and increased BIMEL levels in human lung carcinoma cell line A549 and mouse Sertoli cell line TM4. Mechanismly, the 26S proteasome inhibitors MG132 and bortezomib could effectively inhibit BIMEL degradation induced by As2O3 in BEAS-2B cells. As2O3 activated extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways, but only the ERK1/2 MAPK inhibitor PD98059 blocked BIMEL degradation induced by As2O3. Furthermore, As2O3 induced-phosphorylation of BIMEL at multiple sites was inhibited by ERK1/2 MAPK inhibitor PD98059. Inhibition of As2O3-induced ERK1/2 MAPK phosphorylation increased the levels of BIMEL and cleaved-caspase-3 proteins and decreased BEAS-2B cell viability. As2O3 also markedly mitigated tunicamycin-induced apoptosis of BEAS-2B cells by increasing ERK1/2 phosphorylation and BIMEL degradation. Our results suggest that As2O3-induced activation of the ERK1/2 MAPK pathway increases phosphorylation of BIMEL and promotes BIMEL degradation, thereby alleviating the role of apoptosis in As2O3-induced cell death. This study provides new insights into how to maintain the survival of BEAS-2B cells before malignant transformation induced by high doses of As2O3.

Electroacupuncture inhibits hippocampal neuronal apoptosis and improves cognitive dysfunction in mice with vascular dementia via the JNK signaling pathway.

Electroacupuncture (EA) has been shown to reduce cognitive impairment in vascular dementia (VaD) patients. However, the mechanism of action remains unknown. The c-Jun N-terminal kinase (JNK) signaling pathway plays an important role in apoptosis. Herein, we focused on whether EA can inhibit apoptosis and alleviate cognitive impairment by regulating the JNK signaling pathway using a mouse model of VaD induced by modified bilateral common carotid artery occlusion (BCCAo). In experiment I, 60 mice were randomly divided into a Sham group, BCCAo group, BCCAo + EA group, BCCAo + Sham-EA group, BCCAo + SP group (receiving the selective JNK inhibitor SP600125) and BCCAo + SP + EA group. Morris water maze tests, TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining and flow cytometry were used to evaluate the effect of the EA intervention on VaD. In experiment II, 30 mice were randomly divided into a Sham group, BCCAo group, BCCAo + EA group, BCCAo + SP group and BCCAo + SP + EA group. Western blotting and real-time reverse transcription polymerase chain reaction were used to detect protein and mRNA expression of key factors in the JNK signaling pathway in the hippocampus. EA, SP600125 and EA + SP600125 significantly inhibited hippocampal apoptosis and improved cognitive impairment in VaD model mice. There were no significant differences between the BCCAo group and the BCCAo + Sham-EA group. EA, EA + SP600125 and SP600125 inhibited the phosphorylation of JNK and caspase-3. EA and EA + SP600125 promoted protein and mRNA expression of B-cell lymphoma 2 (Bcl-2) in the hippocampus of VaD mice and inhibited protein and mRNA expression of activator protein (AP)-1, p53 and Bax. EA can reverse cognitive deficits and inhibit hippocampal neuronal apoptosis in VaD model mice, at least partially through inhibition of the JNK signaling pathway and regulation of apoptosis signals.

Actin remodeling mediates ROS production and JNK activation to drive apoptosis-induced proliferation.

Stress-induced cell death, mainly apoptosis, and its subsequent tissue repair is interlinked although our knowledge of this connection is still very limited. An intriguing finding is apoptosis-induced proliferation (AiP), an evolutionary conserved mechanism employed by apoptotic cells to trigger compensatory proliferation of their neighboring cells. Studies using Drosophila as a model organism have revealed that apoptotic caspases and c-Jun N-terminal kinase (JNK) signaling play critical roles to activate AiP. For example, the initiator caspase Dronc, the caspase-9 ortholog in Drosophila, promotes activation of JNK leading to release of mitogenic signals and AiP. Recent studies further revealed that Dronc relocates to the cell cortex via Myo1D, an unconventional myosin, and stimulates production of reactive oxygen species (ROS) to trigger AiP. During this process, ROS can attract hemocytes, the Drosophila macrophages, which further amplify JNK signaling cell non-autonomously. However, the intrinsic components connecting Dronc, ROS and JNK within the stressed signal-producing cells remain elusive. Here, we identified LIM domain kinase 1 (LIMK1), a kinase promoting cellular F-actin polymerization, as a novel regulator of AiP. F-actin accumulates in a Dronc-dependent manner in response to apoptotic stress. Suppression of F-actin polymerization in stressed cells by knocking down LIMK1 or expressing Cofilin, an inhibitor of F-actin elongation, blocks ROS production and JNK activation, hence AiP. Furthermore, Dronc and LIMK1 genetically interact. Co-expression of Dronc and LIMK1 drives F-actin accumulation, ROS production and JNK activation. Interestingly, these synergistic effects between Dronc and LIMK1 depend on Myo1D. Therefore, F-actin remodeling plays an important role mediating caspase-driven ROS production and JNK activation in the process of AiP.

Non-kinase targeting of oncogenic c-Jun N-terminal kinase (JNK) signaling: the future of clinically viable cancer treatments.

c-Jun N-terminal Kinases (JNKs) have been identified as key disease drivers in a number of pathophysiological settings and central oncogenic signaling nodes in various cancers. Their roles in driving primary tumor growth, positively regulating cancer stem cell populations, promoting invasion and facilitating metastatic outgrowth have led JNKs to be considered attractive targets for anti-cancer therapies. However, the homeostatic, apoptotic and tumor-suppressive activities of JNK proteins limit the use of direct JNK inhibitors in a clinical setting. In this review, we will provide an overview of the different JNK targeting strategies developed to date, which include various ATP-competitive, non-kinase and substrate-competitive inhibitors. We aim to summarize their distinct mechanisms of action, review some of the insights they have provided regarding JNK-targeting in cancer, and outline the limitations as well as challenges of all strategies that target JNKs directly. Furthermore, we will highlight alternate drug targets within JNK signaling complexes, including recently identified scaffold proteins, and discuss how these findings may open up novel therapeutic options for targeting discrete oncogenic JNK signaling complexes in specific cancer settings.

Resveratrol inhibits hepatic stellate cell activation by regulating autophagy and apoptosis through the SIRT1 and JNK signaling pathways.

Resveratrol, which is a natural polyphenol found in grapes, berries, peanuts, and medicinal plants, has previously been reported to perform several biological functions, including inhibition of hepatic fibrosis. Activated hepatic stellate cells (HSCs) are the major cellular source of matrix protein-secreting myofibroblasts, which are the major drivers of liver fibrogenesis. Numerous studies on the protective effects of resveratrol against liver fibrosis have focused on the inhibition of HSC activation. Although the underlying mechanisms remain to be fully elucidated, the regulation of autophagy and apoptosis might be intimately related. The mouse HSC line JS1 was stimulated with resveratrol to assess the mechanism and relationship between autophagy and apoptosis. Resveratrol modulated JS1 cell viability in a dose-dependent manner. Moreover, resveratrol inhibited JS1 cell activation and induced autophagy and apoptosis. This antifibrotic effect was attenuated when autophagy was inhibited using chloroquine (CQ) or 3-methyladenine (3-MA) or when apoptosis was inhibited using Z-VAD-FMK. Furthermore, whether the Sirtuin1 (SIRT1) and c-Jun N-terminal kinase (JNK) signaling pathways were associated with the resveratrol-mediated induction of autophagy and apoptosis in JS1 cells was examined. The SIRT1 inhibitor EX527 reversed autophagy, and the JNK inhibitor SP600125 reversed both autophagy and apoptosis induced by resveratrol. These findings suggest that the SIRT1 and JNK signaling pathways may be involved in the resveratrol-mediated inhibition of HSC activation by regulating autophagy and apoptosis. SIRT1 may be responsible for inducing autophagy, while JNK affects both autophagy and apoptosis. This study highlighted autophagy and apoptosis as therapeutic targets by which resveratrol can attenuate fibrosis. PRACTICAL APPLICATIONS: Resveratrol, which is a natural polyphenol found in grapes, berries, peanuts, and medicinal plants, has previously been reported to inhibit hepatic fibrosis. Since activated HSCs are the major drivers of liver fibrogenesis, many studies on the anti-hepatic fibrosis effects of resveratrol have focused on inhibiting HSC activation. The objective of this study was to evaluate the inhibitory effect of resveratrol on HSC activation and focused on the mechanism by which resveratrol modulated autophagy and apoptosis in JS1 cells, a mouse immortalized HSC line. It was shown that resveratrol inhibited HSC activation by inducing autophagy and apoptosis in a dose-dependent manner, and the mechanism may be associated with the SIRT1 and JNK signaling pathways. This study highlighted autophagy and apoptosis as therapeutic targets by which resveratrol can attenuate fibrosis. These findings may provide a new framework for understanding the mechanism by which resveratrol inhibits HSC activation.

Porphyromonas gingivalis Outer Membrane Vesicles Stimulate Gingival Epithelial Cells to Induce Pro-Inflammatory Cytokines via the MAPK and STING Pathways.

Porphyromonas gingivalis (Pg) is a keystone pathogen associated with chronic periodontitis and produces outer membrane vesicles (OMVs) that contain lipopolysaccharide (LPS), gingipains, and pathogen-derived DNA and RNA. Pg-OMVs are involved in the pathogenesis of periodontitis. Pg-OMV-activated pathways that induce the production of the pro-inflammatory cytokines, interleukin (IL)-6, and IL-8 in the human gingival epithelial cell line, OBA-9, were investigated. The role of mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB in levels of Pg-OMV-induced pro-inflammatory cytokines was investigated using Western blot analysis and specific pathway inhibitors. Pg-OMVs induced IL-6 and IL-8 production via the extracellular signal-regulated kinase (Erk) 1/2, c-Jun N-terminal kinase (JNK), p38 MAPK, and NF-κB signaling pathways in OBA-9 cells. In addition, the stimulator of interferon genes (STING), an essential innate immune signaling molecule, was triggered by a cytosolic pathogen DNA. Pg-OMV-induced IL-6 and IL-8 mRNA expression and production were significantly suppressed by STING-specific small interfering RNA. Taken together, these results demonstrated that Pg-OMV-activated Erk1/2, JNK, p38 MAPK, STING, and NF-κB signaling pathways resulting in increased IL-6 and IL-8 expression in human gingival epithelial cells. These results suggest that Pg-OMVs may play important roles in periodontitis exacerbation by stimulating various pathways.

Mitogen-activated protein kinase kinase 7 in inflammatory, cancer, and neurological diseases.

Stress-activated mitogen-activated protein kinase kinase 7 (MKK7) is a member of the dual-specificity mitogen-activated protein kinase family. In the human body, MKK7 controls essential physiological processes, including but not limited to proliferation and differentiation in multiple tissues and organs. MKK7, along with the MKK4 pathway, has been implicated in stress-activated activities and biological events that are mediated by c-Jun N-terminal kinase (JNK) signaling. Although numerous studies have been performed to identify the role of JNK in multiple biological processes, there are limited publications that focus on dissecting the independent role of MKK7. Recent research findings have spurred testing via in vivo genetically deficient models, uncovering previously undocumented JNK-independent functions of MKK7. Here we discuss both JNK-dependent and-independent functions of MKK7 in vivo. This review summarizes the role of MKK7 in inflammation, cytokine production, cancer, and neurological diseases.

G2 and S phase-expressed-1 induces chromosomal instability in esophageal squamous cell carcinoma cells and inhibits cell apoptosis through ROS/JNK signaling.

New diagnostic and therapeutic strategies are urgently needed to improve the prognosis of patients with esophageal squamous cell carcinoma (ESCC), which has high morbidity and mortality. Bioinformatics analysis revealed that cell cycle regulation related molecular G2 and S phase-expressed-1 (GTSE1) was dysregulated in ESCC. In this study, the ectopic expression of GTSE1 was verified in ESCC patients' tissues and cell lines. After overexpression or knockdown of GTSE1 using lentiviral transfection, the effects of GTSE1 on the proliferation, migration, invasion, and apoptosis of ESCC cells were detected. The contribution of GTSE1 in inducing chromosomal missegregation in cells leading to chromosome instability (CIN) has been described. Long-term existence of CIN can increase reactive oxygen species (ROS) generation in ESCC cells, followed by inhibition of apoptosis by activating the c-Jun N-terminal kinase(JNK) signaling pathway, and this inhibition could be relieved after treatment with JNK inhibitor. In vivo experiments, we also confirmed the tumor-promoting effect and mechanism of GTSE1 in ESCC using nude mice model. In this study, we demonstrated that GTSE1 induces CIN in ESCC cells, and increases intracellular ROS production, which leads to cellular oxidative stress, contributes to the activation of the JNK signaling pathway, and thereby inhibits apoptosis leading to ESCC tumorigenesis.

Back Cover: Consumption of Artificial Sweetener Acesulfame Potassium Increases Preterm Risk and Uterine Contraction with Calcium Influx Increased via Myosin Light Chain Kinase–Myosin Light Chain 20 Related Signaling Pathway

Mol. Nutr. Food Res. 2022, 66, 202200298 DOI: 10.1002/mnfr.202200298 The usage of non-nutrition sweeteners (NNS) is rapidly increasing in the food industry, with Acesulfame Potassium (Ace K) as the most prevalently consumed NNS in soft drinks. Exposure to Ace K increases the preterm risk, cytokine secretion and uterine hypercontraction through the modulation of calcium influx and alters MLCK/MLC20 contraction related protein expression through c-Jun N-terminal kinase signaling transduction. This is reported by Yang-Ching Chen, Shih-Min Hsia, and co-workers in article number 2200298.

KCNH6 Enhanced Hepatic Glucose Metabolism through Mitochondrial Ca2+ Regulation and Oxidative Stress Inhibition.

KCNH6 has been proven to affect glucose metabolism and insulin secretion both in humans and mice. Further study revealed that Kcnh6 knockout (KO) mice showed impaired glucose tolerance. However, the precise function of KCNH6 in the liver remains unknown. Mitochondria have been suggested to maintain intracellular Ca2+ homeostasis; ROS generation and defective mitochondria can cause glucose metabolism disorders, including type 2 diabetes (T2D). Here, we found that Kcnh6 attenuated glucose metabolism disorders by decreasing PEPCK and G6pase abundance and induced Glut2 and IRS2 expression. Overexpression of Kcnh6 increased hepatic glucose uptake and glycogen synthesis. Kcnh6 attenuated intracellular and mitochondrial calcium levels in primary hepatocytes and reduced intracellular ROS and mitochondrial superoxide production. Kcnh6 suppressed oxidative stress by inhibiting mitochondrial pathway activation and NADPH oxidase expression. Experiments demonstrated that Kcnh6 expression improved hepatic glucose metabolism disorder through the c-Jun N-terminal kinase and p38MAPK signaling pathways. These results were confirmed by experiments evaluating the extent to which forced Kcnh6 expression rescued metabolic disorder in KO mice. In conclusion, KCNH6 enhanced hepatic glucose metabolism by regulating mitochondrial Ca2+ levels and inhibiting oxidative stress. As liver glucose metabolism is key to T2D, understanding KCNH6 functions may provide new insights into the causes of diabetes.

Dickkopf-1 expression is repressed by oncogenic human papillomaviruses (HPVs) and regulates the Cisplatin sensitivity of HPV-positive cancer cells in a JNK-dependent manner.

Oncogenic human papillomavirus (HPV) types control the phenotype of cervical cancer cells through the sustained expression of the viral E6/E7 oncogenes. Here, we show that they strongly restrain expression of the putative tumor suppressor protein Dkk1 (Dickkopf-1) in HPV-positive cervical cancer cells through the restriction of p53 expression by the continuously expressed endogenous E6 oncoprotein. Moreover, our study reveals that compromised Dkk1 expression is linked to increased resistance of HPV-positive cervical cancer cells toward the proapoptotic activity of Cisplatin. Although Dkk1 can act as a Wnt antagonist, the antiapoptotic effect resulting from Dkk1 repression is not linked to an activation of this pathway. Rather, transcriptome and functional analyses uncover that Dkk1 repression leads to a strongly diminished stimulation of c-Jun N-terminal kinase (JNK) signaling which is required for efficient apoptosis induction by Cisplatin in cervical cancer cells. Further, we observed that Dkk1-depleted cervical cancer cells induce senescence under Cisplatin treatment instead of apoptosis, suggesting that Dkk1 levels can strongly influence the phenotypic response of these cells toward Cisplatin. Collectively, these results provide new insights into the virus/host cell crosstalk in cervical cancer cells by identifying Dkk1 as a cellular target which is maintained under strong negative control by the continuous expression of the HPV oncogenes. Moreover, they identify Dkk1 as a critical determinant for the sensitivity of cervical cancer cells toward Cisplatin, showing that Dkk1 repression leads to increased Cisplatin resistance by impairing proapoptotic JNK signaling.

Manipulation of pantothenate kinase in Anopheles stephensi suppresses pantothenate levels with minimal impacts on mosquito fitness

Pantothenate (Pan) is an essential nutrient required by both the mosquito vector and malaria parasite. We previously demonstrated that increasing pantothenate kinase (PanK) activity and co-enzyme A (CoA) biosynthesis led to significantly decreased parasite infection prevalence and intensity in the malaria mosquito Anopheles stephensi. In this study, we demonstrate that Pan stores in A. stephensi are a limited resource and that manipulation of PanK levels or activity, via small molecule modulators of PanK or transgenic mosquitoes, leads to the conversion of Pan to CoA and an overall reduction in Pan levels with minimal to no effects on mosquito fitness. Transgenic A. stephensi lines with repressed insulin signaling due to PTEN overexpression or repressed c-Jun N-terminal kinase (JNK) signaling due to MAPK phosphatase 4 (MKP4) overexpression exhibited enhanced PanK levels and significant reductions in Pan relative to non-transgenic controls, with the PTEN line also exhibiting significantly increased CoA levels. Provisioning of the PTEN line with the small molecule PanK modulator PZ-2891 increased CoA levels while provisioning Compound 7 decreased CoA levels, affirming chemical manipulation of mosquito PanK. We assessed effects of these small molecules on A. stephensi lifespan, reproduction and metabolism under optimized laboratory conditions. PZ-2891 and Compound 7 had no impact on A. stephensi survival when delivered via bloodmeal throughout mosquito lifespan. Further, PZ-2891 provisioning had no impact on egg production over the first two reproductive cycles. Finally, PanK manipulation with small molecules was associated with minimal impacts on nutritional stores in A. stephensi mosquitoes under optimized rearing conditions. Together with our previous data demonstrating that PanK activation was associated with significantly increased A. stephensi resistance to Plasmodium falciparum infection, the studies herein demonstrate a lack of fitness costs of mosquito Pan depletion as a basis for a feasible, novel strategy to control parasite infection of anopheline mosquitoes.

LINC00313 alleviates osteoarthritis progression in mice through promoting TRAF1 promoter methylation and inhibiting the ASK1/JNK signaling pathway

Objectives This study aimed to explore the underlying role and mechanism of LINC00313 in osteoarthritis (OA) progression. Methods CHON-001 chondrocytes were treated with interleukin (IL)-1β to induce OA in vitro, and then transfected with LINC00313 overexpression plasmids (pcDNA-LINC00313) or small interfering RNA against tumor necrosis factor (TNF) receptor-associated factor 1 (si-TRAF1). Cell viability, apoptosis, levels of inflammatory cytokines tumor necrosis factor-α (TNF-α), IL-6 and IL-8, and expression of extracellular matrix (ECM) degradation related proteins in CHON-001 cells were determined. TRAF1 promoter methylation were was detected with methylation‐specific polymerase chain reaction (MSP) assay. Furthermore, a c-Jun N-terminal kinase (JNK) signaling activator was used to confirm whether the apoptosis signal-regulating kinase 1 (ASK1)/JNK signaling pathway was involved in the function of LINC00313/TRAF1 axis in chondrocytes. In addition, an OA mouse model was established and lentivirus LINC00313 overexpression vector (Lv-LINC00313) was injected, and then inflammatory cytokine levels, ECM protein expression, and pathological changes in cartilage tissues were detected. Results LINC00313 was downregulated and TRAF1 was upregulated in OA cartilage tissues. LINC00313 overexpression or TRAF1 silencing attenuated IL-1β-induced viability inhibition, apoptosis, inflammation and ECM degradation in CHON-001 cells. Moreover, LINC00313 inhibited TRAF1 expression through promoting DNA methyltransferase 1 (DNMT1) mediated promoter methylation. TRAF1 overexpression reversed the effects of LINC00313 on IL-1β-induced chondrocyte injury. LINC00313 overexpression inhibited the ASK1/JNK signaling pathway, and JNK activator reversed the effect. In addition, Lv-LINC00313 treatment alleviated cartilage tissue damage and cartilage matrix degradation in OA mice. Conclusions LINC00313 alleviated OA progression through inhibiting TRAF1 expression and the ASK1/JNK signaling pathway.