Phosphorylation Of c-Jun N-terminal Kinase Research Articles

Silver nanoparticle-induced cell damage via impaired mtROS-JNK/MnSOD signaling pathway

This study investigated the mechanism of silver nanoparticle (AgNP) cytotoxicity from a mitochondrial perspective. The effect of AgNP on manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, against oxidative stress has not been studied in detail. We demonstrated that AgNP decreased MnSOD mRNA level, protein expression, and activity in human Chang liver cells in a time-dependent manner. AgNP induced the production of mitochondrial reactive oxygen species (mtROS), particularly superoxide anion. AgNP was found to increase mitochondrial calcium level and disrupt mitochondrial function, leading to reduced ATP level, succinate dehydrogenase activity, and mitochondrial permeability. AgNP induced cytochrome c release from the mitochondria into the cytoplasm, attenuated the expression of the anti-apoptotic proteins phospho Bcl-2 and Mcl-1, and induced the expression of the pro-apoptotic proteins Bim and Bax. In addition, c-Jun N-terminal kinase (JNK) phosphorylation was significantly increased by AgNP. Treatment with elamipretide (a mitochondria-targeted antioxidant) and SP600125 (a JNK inhibitor) showed the involvement of MnSOD and JNK in these processes. These results indicated that AgNP damaged human Chang liver cells by destroying mitochondrial function through the accumulation of mtROS.

Lead-induced liver fibrosis and inflammation in mice by the AMPK/MAPKs/NF-κB and STAT3/TGF-β1/Smad2/3 pathways: the role of Isochlorogenic acid a.

Lead (Pb) is a nonessential heavy metal, which can cause many health problems. Isochlorogenic acid A (ICAA), a phenolic acid present in tea, fruits, vegetables, coffee, plant-based food products, and various medicinal plants, exerts multiple effects, including anti-oxidant, antiviral, anti-inflammatory and antifibrotic functions. Thus, the purpose of our study was to determine if ICAA could prevent Pb-induced hepatotoxicity in ICR mice. An evaluation was performed on oxidative stress, inflammation and fibrosis, and related signaling. The results indicate that ICAA attenuates Pb-induced abnormal liver function. ICAA reduced liver fibrosis, inflammation and oxidative stress caused by Pb. ICAA abated Pb-induced fibrosis and decreased inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). ICAA abrogated reductions in activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Masson staining revealed that ICAA reduced collagen fiber deposition in Pb-induced fibrotic livers. Western blot and immunohistochemistry analyses showed ICAA increased phosphorylated AMP-activated protein kinase (p-AMPK) expression. ICAA also reduced the expression of collagen I, α-smooth muscle actin (α-SMA), phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated c-jun N-terminal kinase (p-JNK), p-p38, phosphorylated signal transducer and phosphorylated activator of transcription 3 (p-STAT3), transforming growth factor β1 (TGF-β1), and p-Smad2/3 in livers of mice. Overall, ICAA ameliorates Pb-induced hepatitis and fibrosis by inhibiting the AMPK/MAPKs/NF-κB and STAT3/TGF-β1/Smad2/3 pathways.

LINC02257 regulates colorectal cancer liver metastases through JNK pathway

BackgroundLong noncoding RNAs (lncRNAs) have emerged as critical regulators of colorectal cancer (CRC) progression, but their roles and underlying mechanisms in colorectal cancer liver metastases (CRLMs) remain poorly understood. MethodsTo explore the expression patterns and functions of lncRNAs in CRLMs, we analyzed the expression profiles of lncRNAs in CRC tissues using the TCGA database and examined the expression patterns of lncRNAs in matched normal, CRC, and CRLM tissues using clinical samples. We further investigated the biological roles of LINC02257 in CRLM using in vitro and in vivo assays, and verified its therapeutic potential in a mouse model of CRLM. ResultsOur findings showed that LINC02257 was highly expressed in metastatic CRC tissues and its expression was negatively associated with overall survival. Functionally, LINC02257 promoted CRC cell growth, migration, metastasis, and inhibited cell apoptosis in vitro, and enhanced liver metastasis in vivo. Mechanistically, LINC02257 up-regulated phosphorylated c-Jun N-terminal kinase (JNK) to promote CRLM. ConclusionsOur study revealed that LINC02257 played a key role in the proliferation and metastasis of CRC cells through the LINC02257/JNK axis. Targeting this axis may represent a promising therapeutic strategy for the treatment of liver metastases in patients with CRC.

MiR-889-3p targeting BMPR2 promotes the development of retinoblastoma via JNK/MAPK/ERK signaling

MicroRNAs (miRNAs) are vital regulators of tumor pathogenesis, including that of retinoblastoma (Rb). This study investigated the functions and mechanisms of action of miR-889-3p in Rb. BMPR2 and miR-889-3p levels were assessed by quantitative reverse transcription PCR (qRT-PCR) or western blotting. Through several cell function tests, the effects of miR-889-3p and BMPR2 on cell proliferation, migration, and JNK/MAPK/ERK signaling were evaluated. The interaction between miR-889-3p and BMPR2 was investigated using a luciferase reporter assay. In vivo tumor development was investigated using a xenograft test. The association between miR-889-3p and BMPR2 expression was identified using Pearson’s correlation analysis. miR-889-3p was increased in Rb cells, and miR-889-3p knockdown inhibited Rb cell proliferation, migration, and phosphorylation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and ERK1/2 in vitro, as well as tumor growth in vivo. Further, they were inversely associated in Rb tissues and miR-889-3p may directly attached to the 3′-UTR of BMPR2 mRNA. Finally, the inhibition of BMPR2 inverted the negative effects of the miR-889-3p inhibitor on migration, proliferation, and activation of JNK, p38 MAPK, and ERK1/2 in Rb cells. Our results indicate that miR-889-3p, which targets BMPR2 and promotes Rb growth by controlling the JNK/MAPK/ERK pathway, is an oncogene in Rb. These results suggested that the miR-889-3p/BMPR2 axis may be a new therapeutic target for Rb.

Dexmedetomidine attenuates lipopolysaccharide-induced renal cell fibrotic phenotypic changes by inhibiting necroinflammation via activating α2-adrenoceptor: A combined randomised animal and in vitro study

BackgroundAcute kidney injury (AKI) was reported to be one of the initiators of chronic kidney disease (CKD) development. Necroinflammation may contribute to the progression from AKI to CKD. Dexmedetomidine (Dex), a highly selective α2-adrenoreceptor (AR) agonist, has cytoprotective and “anti-” inflammation effects. This study was designed to investigate the anti-fibrotic properties of Dex in sepsis models. MethodsC57BL/6 mice were randomly treated with an i.p. injection of lipopolysaccharides (LPS) (10 mg/kg) alone, LPS with Dex (25 μg/kg), or LPS, Dex and Atipamezole (Atip, an α2-adrenoreceptor antagonist) (500 μg/kg) (n=5/group). Human proximal tubular epithelial cells (HK2) were also cultured and then exposed to LPS (1 μg/ml) alone, LPS and Dex (1 μM), transforming growth factor-beta 1 (TGF-β1) (5 ng/ml) alone, TGF-β1 and Dex, with or without Atip (100 μM) in culture media. Epithelial-mesenchymal transition (EMT), cell necrosis, necroptosis and pyroptosis, and c-Jun N-terminal kinase (JNK) phosphorylation were then determined. ResultsDex treatment significantly alleviated LPS-induced AKI, myofibroblast activation, NLRP3 inflammasome activation, and necroptosis in mice. Atip counteracted its protective effects. Dex attenuated LPS or TGF-β1 induced EMT and also prevented necrosis, necroptosis, and pyroptosis in response to LPS stimulation in the HK2 cells. The anti-EMT effects of Dex were associated with JNK phosphorylation. ConclusionsDex reduced EMT following LPS stimulation whilst simultaneously inhibiting pyroptosis and necroptosis via α2-AR activation in the renal tubular cells. The “anti-fibrotic” and cytoprotective properties and its clinical use of Dex need to be further studied.

Protective effect of hygrolansamycin C against corticosterone-induced toxicity and oxidative stress-mediated via autophagy and the MAPK signaling pathway.

Excessive stress, a major problem in modern societies, affects people of all ages worldwide. Corticosterone is one of the most abundant hormones secreted during stressful conditions and is associated with various dysfunctions in the body. In particular, we aimed to investigate the protective effects of hygrolansamycin C (HYGC) against corticosterone-induced cellular stress, a manifestation of excessive stress prevalent in contemporary societies. We isolated HYGC from Streptomyces sp. KCB17JA11 and subjected PC12 cells to corticosterone-induced stress. The effects of HYGC were assessed by measuring autophagy and the expression of mitogen-activated protein kinase (MAPK) phosphorylation-related genes. We used established cellular and molecular techniques to analyze protein levels and pathways. HYGC effectively protected cells against corticosterone-induced injury. Specifically, it significantly reduced corticosterone-induced oxidative stress and inhibited the expression of autophagy-related proteins induced by corticosterone, which provided mechanistic insight into the protective effects of HYGC. At the signaling level, HYGC suppressed c-Jun N-terminal kinase and extracellular signal-regulated kinase phosphorylation and p38 activation. HYGC is a promising candidate to counteract corticosterone-induced apoptosis and oxidative stress. Autophagy and MAPK pathway inhibition contribute to the protective effects of HYGC. Our findings highlight the potential of HYGC as a therapeutic agent for stress-related disorders and serve as a stepping stone for further exploration and development of stress management strategies.

Anti-Inflammatory Effect of Chamaecyparis obtusa (Siebold & Zucc.) Endl. Leaf Essential Oil.

Chamaecyparis obtusa (Siebold & Zucc.) Endl. (C. obtusa) belongs to the Cupressaceae family and is native to East Asian regions. Essential oils extracted from the leaves, bark, branches, and roots of C. obtusa have both aesthetic and medicinal properties and are thus widely used. However, detailed analyses of the active ingredients of C. obtusa extract are lacking. In this study, the sabinene content in the hydro-distillation of C. obtusa leaf essential oil (COD) was analyzed using GC-MS, and the anti-inflammatory effect of COD was compared with that of pure sabinene. Cell viability was evaluated by MTT assay, and nitric oxide (NO) production was measured using Griess reagent. Relative mRNA and protein levels were analyzed using RT-qPCR and western blot, and secreted cytokines were analyzed using a cytokine array kit. The results showed that both COD and sabinene inhibited the expression of inducible nitric oxide synthase (iNOS) and the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 in lipopolysaccharide (LPS)-induced RAW 264.7 cells. COD and sabinene also reduced the production of pro-inflammatory cytokines interleukin (IL)-1β, IL-6, IL-27, IL-1 receptor antagonist (IL-1ra), and granulocyte-macrophage colony-stimulating factor (GM-CSF). The anti-inflammatory mechanisms of COD and sabinene partially overlap, as COD was shown to inhibit MAPKs and the JAK/STAT axis, and sabinene inhibited MAPKs, thereby preventing LPS-induced macrophage activation.

Ribociclib leverages phosphodiesterase 4 inhibition in the treatment of neutrophilic inflammation and acute respiratory distress syndrome

IntroductionOverwhelming neutrophil activation and oxidative stress significantly contribute to acute respiratory distress syndrome (ARDS) pathogenesis. However, the potential of repurposing ribociclib, a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor used clinically in cancer treatment, for treating neutrophilic ARDS remains uncertain. This study illustrated the ability and underlying mechanism of ribociclib for treating ARDS and neutrophilic inflammation. MethodsPrimary human neutrophils were used to determine the therapeutic effects of ribociclib on respiratory bursts, chemotactic responses, and inflammatory signaling. In vitro and silico analyses were performed to determine the underlying molecular mechanisms. The potential of ribociclib repurposing was evaluated using an in vivo ARDS model in lipopolysaccharide (LPS)-primed mice. ResultsWe found that treatment using ribociclib markedly limited overabundant oxidative stress (reactive oxygen species [ROS]) production and chemotactic responses (integrin levels and adhesion) in activated human neutrophils. Ribociclib was also shown to act as a selective inhibitor of phosphodiesterase 4 (PDE4), thereby promoting the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, leading to the inhibition of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) phosphorylation, and calcium influx. Notably, prophylactic administration and post-treatment with ribociclib ameliorated neutrophil infiltration, lung inflammation, accumulation of oxidative stress, pulmonary destruction, and mortality in mice with LPS-induced ARDS. ConclusionWe demonstrated for the first time that ribociclib serves as a novel PDE4 inhibitor for treating neutrophilic inflammation and ARDS. The repurposing ribociclib and targeting neutrophilic PDE4 offer a potential off-label alternative for treating lung lesions and other inflammatory conditions.

AIM2 regulates autophagy to mitigate oxidative stress in aged mice with acute liver injury

The cytoplasmic pattern recognition receptor, absent in melanoma 2 (AIM2), detects cytosolic DNA, activating the inflammasome and resulting in pro-inflammatory cytokine production and pyroptotic cell death. Recent research has illuminated AIM2’s contributions to PANoptosis and host defense. However, the role of AIM2 in acetaminophen (APAP)-induced hepatoxicity remains enigmatic. In this study, we unveil AIM2’s novel function as a negative regulator in the pathogenesis of APAP-induced liver damage in aged mice, independently of inflammasome activation. AIM2-deficient aged mice exhibited heightened lipid accumulation and hepatic triglycerides in comparison to their wild-type counterparts. Strikingly, AIM2 knockout mice subjected to APAP overdose demonstrated intensified liver injury, compromised mitochondrial stability, exacerbated glutathione depletion, diminished autophagy, and elevated levels of phosphorylated c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK). Furthermore, our investigation revealed AIM2’s mitochondrial localization; its overexpression in mouse hepatocytes amplified autophagy while dampening JNK phosphorylation. Notably, induction of autophagy through rapamycin administration mitigated serum alanine aminotransferase levels and reduced the necrotic liver area in AIM2-deficient aged mice following APAP overdose. Mechanistically, AIM2 deficiency exacerbated APAP-induced acute liver damage and inflammation in aged mice by intensifying oxidative stress and augmenting the phosphorylation of JNK and ERK. Given its regulatory role in autophagy and lipid peroxidation, AIM2 emerges as a promising therapeutic target for age-related acute liver damage treatment.

Cav3.1 T-type calcium channel blocker NNC 55-0396 reduces atherosclerosis by increasing cholesterol efflux

Calcium channel blockers (CCBs) are commonly used as antihypertensive agents. While certain L-type CCBs exhibit antiatherogenic effects, the impact of Cav3.1 T-type CCBs on antiatherogenesis and lipid metabolism remains unexplored. NNC 55–0396 (NNC) is a highly selective blocker of T-type calcium channels (Cav3.1 channels). We investigated the effects of NNC on relevant molecules and molecular mechanisms in human THP-1 macrophages. Cholesterol efflux, an indicator of reverse cholesterol transport (RCT) efficiency, was assessed using [3H]-labeled cholesterol. In vivo, high cholesterol diet (HCD)-fed LDL receptor knockout (Ldlr-/-) mice, an atherosclerosis-prone model, underwent histochemical staining to analyze plaque burden. Treatment of THP-1 macrophages with NNC facilitated cholesterol efflux and reduced intracellular cholesterol accumulation. Pharmacological and genetic interventions demonstrated that NNC treatment or Cav3.1 knockdown significantly enhanced the protein expression of scavenger receptor B1 (SR-B1), ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and liver X receptor alpha (LXRα) transcription factor. Mechanistic analysis revealed that NNC activates p38 and c-Jun N-terminal kinase (JNK) phosphorylation, leading to increased expression of ABCA1, ABCG1, and LXRα-without involving the microRNA pathway. LXRα isrequired for NNC–induced ABCA1 and ABCG1 expression. Administering NNC diminished atherosclerotic lesion area and lipid deposition in HCD-fed Ldlr-/- mice. NNC's anti-atherosclerotic effects, achieved through enhanced cholesterol efflux and inhibition of lipid accumulation, suggest a promising therapeutic approach for hypertensive patients with atherosclerosis. This research highlights the potential of Cav3.1 T-type CCBs in addressing cardiovascular complications associated with hypertension.

Protective Effects on Neuronal SH-SY5Y Cells and Antioxidant Activity of Enzymatic Hydrolyzate from Silkworms Fed the Leaves of Cudrania tricuspidata

We investigated the antioxidant activity and neuroprotective effects of an enzymatic hydrolyzate from silkworms fed the leaves of Cudrania tricuspidata (ESLC) produced by enzymatic treatment. The proteins in silkworms fed the leaves of Cudrania tricuspidata (SLC) were effectively hydrolyzed using enzymatic treatment. The total polyphenols of ESLC were significantly higher, and the superoxide dismutase-like activity and 2,2′-azino-bis (3-thylbenzothiazoline-6-sulfonicacid) diammonium salt radical scavenging capacity of ESLC were significantly increased compared to the SLC group. We evaluated the properties of ESLC to protect SH-SY5Y cells from H2O2-induced oxidative stress. The viability rate of SH-SY5Y neuroblastoma cells was significantly restored when treated with ESLC at a concentration of 100 μg/mL or 250 μg/mL. Furthermore, the mitogen-activated protein kinase (MAPK) pathway was investigated, and ESLC significantly inhibited the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38. Therefore, ESLC can potentially be used as an antioxidant. The polyphenol content increases owing to hydrolysis through enzymatic treatment, which increases the antioxidant effect and inhibits the phosphorylation of JNK, ERK, and p38 by activating the MAPK pathway, which inhibits cell death from oxidative stress and exerts cytoprotective effects.

Co-exposure to fluoride and sulfur dioxide induces abnormal enamel mineralization in rats via the FGF9-mediated MAPK signaling pathway

Fluoride (F) and sulfur dioxide (SO2) contamination is recognized as a public health concern worldwide. Our previous research has shown that Co-exposure to F and SO2 can cause abnormal enamel mineralization. Ameloblastin (AMBN) plays a crucial role in the process of enamel mineralization. However, the process by which simultaneous exposure to F and SO2 influences enamel formation by regulating AMBN expression still needs to be understood. This study aimed to establish in vivo and in vitro models of F–SO2 Co-exposure and investigate the relationship between AMBN and abnormal enamel mineralization. By overexpressing/knocking out the Fibroblast Growth Factor 9 (FGF9) gene, we investigated the impact of FGF9-mediated Mitogen-Activated Protein Kinase (MAPK) signaling on AMBN synthesis to elucidate the mechanism underlying the induction of abnormal enamel mineralization by F–SO2 Co-exposure in rats. The results showed that F–SO2 exposure damaged the structure of rat enamel and ameloblasts. When exposed to F or SO2, gradual increases in the protein expression of FGF9 and phosphorylated p38 mitogen-activated protein kinase (p-P38) were observed. Conversely, the protein levels of AMBN, phosphorylated extracellular signal-regulated kinase (p-ERK), and phosphorylated c-Jun N-terminal kinase (p-JNK) were decreased. AMBN expression was significantly correlated with FGF9, p-ERK, and p-JNK expression in ameloblasts. Interestingly, FGF9 overexpression reduced the levels of p-ERK and p-JNK, worsening the inhibitory effect of F–SO2 on AMBN. Conversely, FGF9 knockout increased the phosphorylation of ERK and JNK, partially reversing the F–SO2-induced downregulation of AMBN. Taken together, these findings strongly demonstrate that FGF9 plays a critical role in F–SO2-induced abnormal enamel mineralization by regulating AMBN synthesis through the JNK and ERK pathways.

[Mechanism of Guizhi Gancao Decoction against myocardial ischemia-reperfusion injury based on network pharmacology and experimental verification].

This study employed network pharmacology to investigate the effect of Guizhi Gancao Decoction(GGD) on myocardial ischemia-reperfusion injury(MI/RI) in rats and decipher the underlying mechanism. Firstly, the chemical components and targets of GGD against MI/RI were searched against the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP), SwissTargetPrediction, and available articles. STRING and Cytoscape 3.7.2 were used to establish the protein-protein interaction(PPI) network for the common targets, and then Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analyses were carried out for the core targets. The "drug-active component-target-pathway" network was built. Furthermore, molecular docking between key active components and targets was conducted in AutoDock Vina. Finally, the rat model of MI/RI was established, and the myocardial infarction area was measured. Hematoxylin-eosin(HE) staining and transmission electron microscopy(TEM) were employed to detect cardiomyocyte pathology and ultrastructural changes. Western blot was employed to determine the expression of related proteins in the myocardial tissue. A total of 75 chemical components of GGD were screened out, corresponding to 318 targets. The PPI network revealed 46 core targets such as tumor protein p53(TP53), serine/threonine kinase 1(AKT1), signal transducer and activator of transcription 3(STAT3), non-receptor tyrosine kinase(SRC), mitogen-activated protein kinase 1(MAPK1), MAPK3, and tumor necrosis factor(TNF). According to GO and KEGG enrichment analyses, the core targets mainly affected the cell proliferation and migration, signal transduction, apoptosis, and transcription, involving advanced glycation end products-receptor(AGE-RAGE), MAPK and other signaling pathways in cancers and diabetes complications. The molecular docking results showed that the core components of GGD, such as licochalcone A,(+)-catechin, and cinnamaldehyde, had strong binding activities with the core target proteins, such as MAPK1 and MAPK3. The results of animal experiments showed that compared with the model group, GGD significantly increase superoxide dismutase, decreased malondialdehyde, lactate dehydrogenase, and creatine kinase-MB, and reduced the area of myocardial infarction. HE staining and TEM results showed that GGD pretreatment restored the structure of cardiomyocytes and alleviated the pathological changes and ultrastructural damage of mitochondria in the model group. In addition, GGD significantly down-regulated the phosphorylation of c-Jun N-terminal kinase and p38 and up-regulate that of extracellular regulated kinases 1/2 in the myocardial tissue. The results suggested that GGD may exert the anti-MI/RI effect by regulating the MAPK signaling pathway via the synergistic effects of Cinnamomi Ramulus and Glycyrrhizae Radix et Rhizoma.

Mesenchymal Stem/Stromal Cells Induce Myeloid-Derived Suppressor Cells in the Bone Marrow via the Activation of the c-Jun N-Terminal Kinase Signaling Pathway.

Our previous study demonstrated that mesenchymal stem/stromal cells (MSCs) induce the differentiation of myeloid-derived suppressor cells (MDSCs) in the bone marrow (BM) under inflammatory conditions. In this study, we aimed to investigate the signaling pathway involved. RNA-seq revealed that the mitogen-activated protein kinase (MAPK) pathway exhibited the highest number of upregulated genes in MSC-induced MDSCs. Western blot analysis confirmed the strong phosphorylation of c-Jun N-terminal kinase (JNK) in BM cells cocultured with MSCs under granulocyte-macrophage colony-stimulating factor stimulation, whereas p38 kinase activation remained unchanged in MSC-cocultured BM cells. JNK inhibition by SP600125 abolished the expression of Arg1 and Nos2, hallmark genes of MDSCs, as well as Hif1a, a molecule mediating monocyte functional reprogramming toward a suppressive phenotype, in MSC-cocultured BM cells. JNK inhibition also abrogated the effects of MSCs on the production of TGF-β1, TGF-β2 and IL-10 in BM cells. Furthermore, JNK inhibition increased Tnfa expression, while suppressing IL-10 production, in MSC-cocultured BM cells in response to lipopolysaccharides. Collectively, our results suggest that MSCs induce MDSC differentiation and promote immunoregulatory cytokine production in BM cells during inflammation, at least in part, through the activation of the JNK-MAPK signaling pathway.

Oxaloacetic acid induces muscle energy substrate depletion and fatigue by JNK-mediated mitochondrial uncoupling.

Fatigue is a common phenomenon closely related to physical discomfort and numerous diseases, which is severely threatening the life quality and health of people. However, the exact mechanisms underlying fatigue are not fully characterized. Herein, we demonstrate that oxaloacetic acid (OAA), a crucial tricarboxylic acid cycle intermediate, modulates the muscle fatigue. The results showed that serum OAA level was positively correlated with fatigue state of mice. OAA-treated induced muscle fatigue impaired the exercise performance of mice. Mechanistically, OAA increased the c-Jun N-terminal kinase (JNK) phosphorylation and uncoupling protein 2 (UCP2) levels in skeletal muscle, which led to decreased energy substrate and enhanced glycolysis. On the other hand, OAA boosted muscle mitochondrial oxidative phosphorylation uncoupled with energy production. In addition, either UCP2 knockout or JNK inhibition totally reversed the effects of OAA on skeletal muscle. Therein, JNK mediated UCP2 activation with OAA-treated. Our studies reveal a novel role of OAA in skeletal muscle metabolism, which would shed light on the mechanism of muscle fatigue and weakness.

Effects of ivabradine on myocardial autophagia and apoptosis in isoprenaline-induced heart failure in mice.

To investigate the effects and mechanisms of ivabradine (IVA) on isoprenaline-induced cardiac injury. Forty male C57BL/6 mice were randomly divided into control group, model group, high-dose IVA group, and low-dose IVA group. The control group was given saline, other groups were given subcutaneous injections of isoproterenol (ISO) 5 mg/kg/d to make the myocardial remodeling model. A corresponding dose of IVA (high dose 50 mg/kg/d, low dose 10 mg/kg/d) was given by gavage (30 days). A transthoracic echocardiogram was obtained to detect the structure and function of the heart. An electron microscope was used to explore the cardiomyocytes' apoptosis and autophagy. HE staining and Masson's trichrome staining were performed to explore myocardial hypertrophy and fibrosis. Western blot was used to detect Bax, Bcl-2, cleaved caspase-3, Becline-1, LC3, phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK), phosphorylated extracellular regulated protein kinases1/2 (p-ERK1/2), phosphorylated c-Jun N-terminal kinase (p-JNK), and α-smooth muscle actin (α-SMA) in the myocardium. Heart rate in the IVA groups was reduced, and the trend of heart rate reduction was more obvious in the high-dose group. Echocardiography showed that IVA improved the cardiac structure and function compared to the model group. IVA attenuated cardiac fibrosis, decreased cardiomyocyte apoptosis, and increased autophagy. The phosphorylated MAPK in the ISO-induced groups was increased. IVA treatment decreased the p-p38MAPK level. There were no differences in p-ERK and p-JNK levels. The beneficial effects of IVA on myocardial injury are related to blocking the p38MAPK signal pathway, decreasing cardiomyocyte apoptosis, and increasing cardiomyocyte autophagy.

Electroacupuncture protects against the striatum of ischemia stroke by inhibiting the HMGB1/RAGE/p-JNK signaling pathways

The striatum (Str) is injured 20 min after permanent ischemic stroke, leading to neurological deficits. Here, we aimed to explore the effect of electroacupuncture (EA) on ischemic stroke and elucidate the possible underlying mechanism. Rat permanent middle cerebral artery occlusion (pMCAO) model, EA treatment, sham-EA (SEA) treatment, beam-balance test, hematoxylin and eosin (HE) staining, Nissl staining, immunofluorescence staining, and Western blot were used to investigate the role of EA in pMCAO. The results showed that balance ability and motor coordination were obviously injured after pMCAO. EA improved balance ability and motor coordination in pMCAO rats. EA reduced striatal injury by reducing the expression of high-mobility group box 1(HMGB1)/receptor for advanced glycation end products (RAGE)/phosphorylated C-Jun N-terminal kinase (p-JNK), whereas SEA did not. Thus, EA plays a neuroprotective role during pMCAO injury, which may be related to the inhibition of HMGB1/RAGE/p-JNK expression.

The ginsenoside Rg2 downregulates MMP-1 expression in keratinocyte (HaCaT)-conditioned medium-treated human fibroblasts (Hs68)

Keratinocytes exposed to UVB induce the production of cytokines, which activate fibroblasts and increase the expression of matrix metalloproteinases (MMPs). The increased expression of MMPs leads to connective tissue damage and wrinkle formation, resulting in skin aging. In this study, we used human dermal fibroblasts cultured in UVB-irradiated keratinocyte-conditioned medium (UV CM) to investigate the potential anti-aging effects of the ginsenoside Rg2 on skin. The inhibitory effect of Rg2 on the MMP-1 gene and protein was determined by real-time PCR and ELISA. We also examined the expression levels of proteins in the mitogen-activated protein kinase (MAPK) signaling pathway using western blotting, to elucidate the underlying mechanism of the inhibitory effect of Rg2. Rg2 inhibited MMP-1 mRNA and protein expression in a concentration-dependent manner. We found that Rg2 inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) but not that of p38. Therefore, our results suggest that Rg2 is a potential material for the prevention and treatment of photoaging.

Prophylactic function of Garcinia morella dried fruits in preventing intestinal barrier disruption by lowering tight junction permeability and inflammation

The most frequent cause of gastrointestinal disorders characterized by inflammation and disturbance of the gastrointestinal system, is infection from various bacterial strains. Garcinia morella (Gaertn.) Desr. (Clusiaceae) a well-known traditional food is also used in healing digestive disorders for centuries. However, its protective activity in the pathogenesis of pathogen-induced gut disruption remains unclear. This study investigated the beneficial effect of G. morella fruits in remediating pathogen-induced intestinal disruption in Caco-2 cells. The antimicrobial activity of G. morella hydroalcoholic fruit extract with known chemical composition against the opportunistic pathogens, Escherichia coli and Enterococcus faecalis were evaluated. Transepithelial electrical resistance and dextran permeability assay were performed to evaluate the permeability in Caco-2 monolayers. Western blot assays were performed to detect the expression of the intestinal tight junction proteins: zonula occludens-1, claudin-1, occludin, and E-cadherin; and phosphorylation of inflammatory markers: ERK (Extracellular signal-regulated kinase), and JNK (Jun N-terminal kinase). Three bioactive compounds: garcinol, hydroxycitric acid, and hydroxycitric acid lactone were identified, qualitatively and quantitatively assessed with HPLC (high performance liquid chromatography). G. morella hydroalcoholic extract and its compounds prevented the decrease in transepithelial electrical resistance caused by pathogen infection in Caco-2 cells. G. morella and compounds also decreased permeability in Caco-2 monolayer, increased by pathogen infection. G. morella and garcinol enhanced tight junction protein expression. A decrease in extracellular-signal-regulated kinase and c-Jun N-terminal kinase phosphorylation was observed in G. morella and garcinol-treated cells. Overall, the results showed the potential of G. morella and its compounds in maintaining intestinal integrity and validate its traditional claims in ameliorating stomach ailments. The study also provided new guidance in development of nutraceuticals that aid in curing leaky gut.

Electroacupuncture reduces cerebral ischemia-induced neuronal damage in the hippocampal CA1 region in rats by inhibiting HMGB1 and p-JNK overexpression

Background The cornu ammonis 1 (CA1) region of the hippocampus is a sensitive area that is susceptible to injury caused by cerebral ischemia. High-mobility group box 1 (HMGB1) and phosphorylated c-Jun N-terminal kinase (p-JNK) play important roles in mediating cerebral ischemic injury. Objective To elucidate the mechanism through which electroacupuncture (EA) via the Baihui (GV20) and Zusanli (ST36) acupoints protects neurons. Methods A rat model of permanent middle cerebral artery occlusion (pMCAO) was established. Sprague-Dawley rats were divided into four groups: sham-operated control, pMCAO control, EA, and sham-EA (SEA). In the EA and SEA groups, the GV20 and ST36 acupoints were selected for treatment. However, the SEA group was treated only by superficial pricking of the skin at the two acupoints without the application of electricity. Neurological function was assessed using the neurological deficit function score, and neuronal damage was detected through Nissl staining. HMGB1 and p-JNK expression was evaluated using immunohistochemical staining and western blot assays. Results The behavioural experiments showed that the EA treatment improved the neurological deficits in the pMCAO rats. The Nissl staining results revealed that EA reduced neural tissue damage. The immunohistochemical staining and western blot results showed that EA inhibited HMGB1 and p-JNK overexpression. By contrast, none of these EA effects were observed in the SEA group. Conclusion EA may reduce ischemia-induced neuronal damage in the hippocampal CA1 region by inhibiting the overexpression of both HMGB1 and p-JNK.