Anti-cancer effects of plant-derived Micromonospora sp. M2 against A549 and MCF-7 cell lines.

The huge diversity of secondary bioactive metabolites, such as antibiotic and anticancer compounds produced by Micromonospora sp., makes it an attractive target for study. Here, we explored the anti-proliferative activities of Micromonospora sp. M2 extract (MBE) in relation to its pro-oxidative activities in A549 and MCF7 cell lines. Anti-proliferative effects were assessed by treating cells with MBE. We found that treatment with MBE decreased cell proliferation and increased intracellular reactive oxygen species, and that these observations were facilitated by the suppression of the PI3K-AKT pathway, alterations to the Bcl/Bad ratio, and increased caspase activity. These observations also demonstrated that MBE induced apoptotic cell death in cell lines. In addition, the phosphorylation of P38 and c-Jun N-terminal kinase (JNK) were upregulated following MBE treatment in both cell lines. Collectively, these results indicate that MBE acts as an anticancer agent via oxidative stress and JNK/mitogen-activated protein kinase pathway activation, enhancing apoptotic cell death in cell lines.

Stress-Activated Protein Kinases in Intervertebral Disc Degeneration: Unraveling the Impact of JNK and p38 MAPK.

Intervertebral disc degeneration (IDD) is a major cause of lower back pain. The pathophysiological development of IDD is closely related to the stimulation of various stressors, including proinflammatory cytokines, abnormal mechanical stress, oxidative stress, metabolic abnormalities, and DNA damage, among others. These factors prevent normal intervertebral disc (IVD) development, reduce the number of IVD cells, and induce senescence and apoptosis. Stress-activated protein kinases (SAPKs), particularly, c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK), control cell signaling in response to cellular stress. Previous studies have shown that these proteins are highly expressed in degenerated IVD tissues and are involved in complex biological signal-regulated processes. Therefore, we summarize the research reports on IDD related to JNK and p38 MAPK. Their structure, function, and signal regulation mechanisms are comprehensively and systematically described and potential therapeutic targets are proposed. This work could provide a reference for future research and help improve molecular therapeutic strategies for IDD.

Deoxynivalenol leads to endoplasmic reticulum stress-mediated apoptosis via the IRE1/JNK/CHOP pathways in porcine embryos.

The cytotoxic mycotoxin deoxynivalenol (DON) reportedly has adverse effects on oocyte maturation and embryonic development in pigs. Recently, the interplay between cell apoptosis and endoplasmic reticulum (ER) stress has garnered increasing attention in embryogenesis. However, the involvement of the inositol-requiring enzyme 1 (IRE1)/c-jun N-terminal kinase (JNK)/C/EBP homologous protein (CHOP) pathways of unfolded protein response (UPR) signaling in DON-induced apoptosis in porcine embryos remains unknown. In this study, we revealed that exposure to DON (0.25 µM) substantially decreased cell viability until the blastocyst stage in porcine embryos, concomitant with initiation of cell apoptosis through the IRE1/JNK/CHOP pathways in response to ER stress. Quantitative PCR confirmed that UPR signaling-related transcription factors were upregulated in DON-treated porcine blastocysts. Western blot analysis showed that IRE1/JNK/CHOP signaling was activated in DON-exposed porcine embryos, indicating that ER stress-associated apoptosis was instigated. The ER stress inhibitor tauroursodeoxycholic acid protected against DON-induced ER stress in porcine embryos, indicating that the toxic effects of DON on early developmental competence of porcine embryos can be prevented. In conclusion, DON exposure impairs the developmental ability of porcine embryos by inducing ER stress-mediated apoptosis via IRE1/JNK/CHOP signaling.

The lincRNA JUNI regulates the stress-dependent induction of c-Jun, cellular migration and survival through the modulation of the DUSP14-JNK axis.

Cancer cells employ adaptive mechanisms to survive various stressors, including genotoxic drugs. Understanding the factors promoting survival is crucial for developing effective treatments. In this study, we unveil a previously unexplored long non-coding RNA, JUNI (JUN-DT, LINC01135), which is upregulated by genotoxic drugs through the activation of stress-activated MAPKs, JNK, and p38 and consequently exerts positive control over the expression of its adjacent gene product c-Jun, a well-known oncoprotein, which transduces signals to multiple transcriptional outputs. JUNI regulates cellular migration and has a crucial role in conferring cellular resistance to chemotherapeutic drugs or UV radiation. Depletion of JUNI markedly increases the sensitivity of cultured cells and spheroids to chemotherapeutic agents. We identified 57 proteins interacting with JUNI. The activity of one of them the MAPK phosphatase and inhibitor, DUSP14, is counteracted by JUNI, thereby, facilitating efficient JNK phosphorylation and c-Jun induction when cells are exposed to UV radiation. The antagonistic interplay with DUSP14 contributes not only to c-Jun induction but also augments the survival of UV-exposed cells. In summary, we introduce JUNI as a novel stress-inducible regulator of c-Jun, positioning it as a potential target for enhancing the sensitivity of cancer cells to chemotherapy.

Oridonin promotes RSL3-induced ferroptosis in breast cancer cells by regulating the oxidative stress signaling pathway JNK/Nrf2/HO-1.

The incidence and mortality of breast cancer, the most common malignant tumor among women in the world, are increasing year by year, which greatly threatens women's health. Ferroptosis is an iron and lipid reactive oxygen species (ROS)-dependent process, a novel form of cell death that is distinct from apoptosis and is closely related to the progression of breast cancer. Inducing the occurrence of ferroptosis in tumor cells can effectively block its malignant progress in vivo. Oridonin (ORI), the primary active ingredient extracted from the Chinese herbal medicine Rabdosia rubescens, has been shown to cause glutathione depletion and directly inhibit glutathione peroxidase 4 induced cell death by ferroptosis, but its mechanism of action in breast cancer remains inadequately elucidated. Therefore, we further investigated whether ORI could promote RSL3-induced ferroptosis in breast cancer cells by regulating the oxidative stress pathway JNK/Nrf2/HO-1. In our study, we assessed cell survival of RSL3 and ORI treatment by MTT assay, and found that co-treatment with RSL3 and ORI inhibited cell proliferation, as evidenced by the cloning assay. To investigate the ability of ORI to promote RSL3-induced ferroptosis in breast cancer cells, we measured levels of ROS, malondialdehyde, glutathione, superoxide dismutase, and Fe2+ content. Lipid peroxidation, ROS, and mitochondrial membrane potential levels induced by co-treatment of ORI with RSL3 were reversed by ferrostatin-1, further confirming that the cell death induced by RSL3 and ORI was ferroptosis rather than other programmed cell death modes. Moreover, RSL3 and ORI co-treatment regulated the JNK/Nrf2/HO-1 axis, as demonstrated by western blotting and target activator validation. Our results showed that ORI could enhance the inhibitory effect of RSL3 on breast cancer cells viability via the induction of ferroptosis. Mechanistically, it potentiated RSL3-induced ferroptosis in breast cancer cells by activating the JNK/Nrf2/HO-1 axis. This study provides a theoretical basis for the application of ORI based on the mechanism of ferroptosis, and provides potential natural drug candidates for cancer prevention and treatment.

Hyperoside inhibits EHV-8 infection via alleviating oxidative stress and IFN production through activating JNK/Keap1/Nrf2/HO-1 signaling pathways.

Equine herpesvirus type 8 (EHV-8) causes abortion and respiratory disease in horses and donkeys, leading to serious economic losses in the global equine industry. Currently, there is no effective vaccine or drug against EHV-8 infection, underscoring the need for a novel antiviral drug to prevent EHV-8-induced latent infection and decrease the pathogenicity of this virus. The present study demonstrated that hyperoside can exert antiviral effects against EHV-8 infection in RK-13 (rabbit kidney cells), MDBK (Madin-Darby bovine kidney), and NBL-6 cells (E. Derm cells). Mechanistic investigations revealed that hyperoside induces heme oxygenase-1 expression by activating the c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis, alleviating oxidative stress and triggering a downstream antiviral interferon response. Accordingly, hyperoside inhibits EHV-8 infection. Meanwhile, hyperoside can also mitigate EHV-8-induced injury in the lungs of infected mice. These results indicate that hyperoside may serve as a novel antiviral agent against EHV-8 infection.IMPORTANCEHyperoside has been reported to suppress viral infections, including herpesvirus, hepatitis B virus, infectious bronchitis virus, and severe acute respiratory syndrome coronavirus 2 infection. However, its mechanism of action against equine herpesvirus type 8 (EHV-8) is currently unknown. Here, we demonstrated that hyperoside significantly inhibits EHV-8 adsorption and internalization in susceptible cells. This process induces HO-1 expression via c-Jun N-terminal kinase/nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 axis activation, alleviating oxidative stress and triggering an antiviral interferon response. These findings indicate that hyperoside could be very effective as a drug against EHV-8.

Curcumin Analog L48H37 Induces Apoptosis in Human Oral Cancer Cells by Activating Caspase Cascades and Downregulating the Inhibitor of Apoptosis Proteins through JNK/p38 Signaling.

L48H37 is a synthetic curcumin analog that has anticancer potentials. Here, we further explored the anticancer effect of L48H37 on oral cancer cells and its mechanistic acts. Cell cycle distribution was assessed using flow cytometric analysis. Apoptosis was elucidated by staining with PI/Annexin V and activation of the caspase cascade. Cellular signaling was explored using apoptotic protein profiling, Western blotting, and specific inhibitors. Our findings showed that L48H37 significantly reduced the cell viability of SCC-9 and HSC-3 cells, resulting in sub-G1 phase accumulation and increased apoptotic cells. Apoptotic protein profiling revealed that L48H37 increased cleaved caspase-3, and downregulated cellular inhibitor of apoptosis protein 1 (cIAP1) and X-linked inhibitor of apoptosis protein (XIAP) in SCC-9 cells, and the downregulated cIAP1 and XIAP in both oral cancer cells were also demonstrated by Western blotting. Meanwhile, L48H37 triggered the activation of caspases and mitogen-activated protein kinases (MAPKs). The involvement of c-Jun N-terminal kinase (JNK) and p38 MAPK (p38) in the L48H37-triggered apoptotic cascade in oral cancer cells was also elucidated by specific inhibitors. Collectively, these findings indicate that L48H37 has potent anticancer activity against oral cancer cells, which may be attributed to JNK/p38-mediated caspase activation and the resulting apoptosis. This suggests a potential benefit for L48H37 for the treatment of oral cancer.

Melanoma differentiation-associated protein 5 prevents cardiac hypertrophy via apoptosis signal-regulating kinase 1-c-Jun N-terminal kinase/p38 signaling.

Pathological cardiac hypertrophy (CH) is driven by maladaptive changes in myocardial cells in response to pressure overload or other stimuli. CH has been identified as a significant risk factor for the development of various cardiovascular diseases, ultimately resulting in heart failure. Melanoma differentiation-associated protein 5 (MDA5), encoded by interferon-induced with helicase C domain 1 (IFIH1), is a cytoplasmic sensor that primarily functions as a detector of double-stranded ribonucleic acid (dsRNA) viruses in innate immune responses; however, its role in CH pathogenesis remains unclear. Thus, the aim of this study was to examine the relationship between MDA5 and CH using cellular and animal models generated by stimulating neonatal rat cardiomyocytes with phenylephrine and by performing transverse aortic constriction on mice, respectively. MDA5 expression was upregulated in all models. MDA5 deficiency exacerbated myocardial pachynsis, fibrosis, and inflammation in vivo, whereas its overexpression hindered CH development in vitro. In terms of the underlying molecular mechanism, MDA5 inhibited CH development by promoting apoptosis signal-regulating kinase 1 (ASK1) phosphorylation, thereby suppressing c-Jun N-terminal kinase/p38 signaling pathway activation. Rescue experiments using an ASK1 activation inhibitor confirmed that ASK1 phosphorylation was essential for MDA5-mediated cell death. Thus, MDA5 protects against CH and is a potential therapeutic target.

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.

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

BACKGROUND: Non-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. PURPOSE: To investigate the potential anticancer mechanism of Tan IIA and its impact on immunotherapy in NSCLC. METHODS: Cytotoxicity 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. RESULTS: Tan 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. CONCLUSION: The 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.

HIF-1α is a "brake" in JNK-mediated activation of amyloid protein precursor and hyperphosphorylation of tau induced by T-2 toxin in BV2 cells.

Mycotoxins have been shown to activate multiple mechanisms that may potentially lead to the progression of Alzheimer's disease (AD). Overexpression/aberrant cleavage of amyloid precursor protein (APP) and hyperphosphorylation of tau (P-tau) is hallmark pathologies of AD. Recent advances suggest that the neurotoxic effects of mycotoxins involve c-Jun N-terminal kinase (JNK) and hypoxia-inducible factor-1α (HIF-1α) signaling, which are closely linked to the pathogenesis of AD. Due to the high toxicity and broad contamination of T-2 toxin, we assessed how T-2 toxin exposure alters APP and P-tau formation in BV2 cells and determined the underlying roles of HIF-1α and JNK signaling. The findings revealed that T-2 toxin stimulated the expression of HIF-1α and hypoxic stress factors in addition to increasing the expression of APP and P-tau. Additionally, HIF-1α acted as a "brake" on the induction of APP and P-tau expression by negatively regulating these proteins. Notably, T-2 toxin activated JNK signaling, which broke this "brake" to promote the formation of APP and P-tau. Furthermore, the cytoskeleton was an essential target for T-2 toxin to exert cytotoxicity, and JNK/HIF-1α participated in this damage. Collectively, when the T-2 toxin induces the production of APP and P-tau, JNK might interfere with HIF-1α's protective function. This study will provide clues for further research on the neurotoxicity of mycotoxins.

The Role of the Dysregulated JNK Signaling Pathway in the Pathogenesis of Human Diseases and Its Potential Therapeutic Strategies: A Comprehensive Review.

JNK is named after c-Jun N-terminal kinase, as it is responsible for phosphorylating c-Jun. As a member of the mitogen-activated protein kinase (MAPK) family, JNK is also known as stress-activated kinase (SAPK) because it can be activated by extracellular stresses including growth factor, UV irradiation, and virus infection. Functionally, JNK regulates various cell behaviors such as cell differentiation, proliferation, survival, and metabolic reprogramming. Dysregulated JNK signaling contributes to several types of human diseases. Although the role of the JNK pathway in a single disease has been summarized in several previous publications, a comprehensive review of its role in multiple kinds of human diseases is missing. In this review, we begin by introducing the landmark discoveries, structures, tissue expression, and activation mechanisms of the JNK pathway. Next, we come to the focus of this work: a comprehensive summary of the role of the deregulated JNK pathway in multiple kinds of diseases. Beyond that, we also discuss the current strategies for targeting the JNK pathway for therapeutic intervention and summarize the application of JNK inhibitors as well as several challenges now faced. We expect that this review can provide a more comprehensive insight into the critical role of the JNK pathway in the pathogenesis of human diseases and hope that it also provides important clues for ameliorating disease conditions.

Esketamine inhibits the c-Jun N-terminal kinase pathway in the spinal dorsal horn to relieve bone cancer pain in rats.

Cancer-induced bone pain (CIBP) is one of the most common and feared symptoms in patients with advanced tumors. The X-C motif chemokine ligand 12 (CXCL12) and the CXCR4 receptor have been associated with glial cell activation in bone cancer pain. Moreover, mitogen-activated protein kinases (MAPKs), as downstream CXCL12/CXCR4 signals, and c-Jun, as activator protein AP-1 components, contribute to the development of various types of pain. However, the specific CIBP mechanisms remain unknown. Esketamine is a non-selective N-methyl-d-aspartic acid receptor (NMDA) inhibitor commonly used as an analgesic in the clinic, but its analgesic mechanism in bone cancer pain remains unclear. We used a tumor cell implantation (TCI) model and explored that CXCL12/CXCR4, p-MAPKs, and p-c-Jun were stably up-regulated in the spinal cord. Immunofluorescence images showed activated microglia in the spinal cord on day 14 after TCI and co-expression of CXCL12/CXCR4, p-MAPKs (p-JNK, p-ERK, p-p38 MAPK), and p-c-Jun in microglia. Intrathecal injection of the CXCR4 inhibitor AMD3100 reduced JNK and c-Jun phosphorylations, and intrathecal injection of the JNK inhibitor SP600125 and esketamine also alleviated TCI-induced pain and reduced the expression of p-JNK and p-c-Jun in microglia. Overall, our data suggest that the CXCL12/CXCR4-JNK-c-Jun signaling pathway of microglia in the spinal cord mediates neuronal sensitization and pain hypersensitivity in cancer-induced bone pain and that esketamine exerts its analgesic effect by inhibiting the JNK-c-Jun pathway.

Blockade of isoprenoids biosynthesis by simvastatin induces autophagy-mediated cell death via downstream c-Jun N-terminal kinase activation and cell cycle dysregulation in canine T-cell lymphoma cells.

Statins are inhibitors of the mevalonic acid pathway that mediates cellular metabolism by producing cholesterol and isoprenoids and are widely used in treating hypercholesterolaemia in humans. Lipophilic statins, including simvastatin, induce death in various tumour cells. However, the cytotoxic mechanisms of statins in tumour cells remain largely unexplored. This study aimed to elucidate the cytotoxic mechanisms of simvastatin in canine lymphoma cells. Simvastatin induced cell death via c-Jun N-terminal kinase (JNK) activation and autophagy in canine T-cell lymphoma cell lines Ema and UL-1, but not in B-cell lines. Cell death was mediated by induction of caspase-dependent apoptosis in UL-1 cells, but not in Ema cells. Blockade of autophagy by lysosomal inhibitors attenuated simvastatin-induced JNK activation and cell death. Isoprenoids, including farnesyl pyrophosphate and geranylgeranyl pyrophosphate, attenuated simvastatin-induced autophagy, JNK activation, and cell death. In UL-1 cells, simvastatin treatment resulted in the cell cycle arrest at the G2/M phase, which was altered to G0/1 phase cell cycle arrest by treatment with lysosomal inhibitors. These findings demonstrate that depletion of isoprenoids by simvastatin induces autophagy-mediated cell death via downstream JNK activation and cell cycle dysregulation in canine T-cell lymphoma cells.

Sanguinarine Triggers Apoptosis in Cutaneous Squamous Cell Carcinoma Cells through Reactive Oxygen Species-Dependent c-Jun N-Terminal Kinase Signaling Pathway.

BACKGROUND: The benzophenanthridine Sanguinarine (Sng) is one of the most abundant root alkaloids with a long history of investigation and pharmaceutical applications. The cytotoxicity of Sng against various tumor cells is well-established; however, its antiproliferative and apoptotic potential against the cutaneous squamous cell carcinoma (cSCC) cells remains unknown. In the present study, we investigated the anti-cancer potential of Sng against cSCC cells and elucidated the underlying mechanisms relevant to the drug action. METHODS: The inhibitory effect of Sng on cSCC cells was evaluated by analyzing cell viability, colony-forming ability and multi-caspase activity. Apoptosis was quantified through Annexin-V/Propidium iodide flow cytometric assay and antagonized by pan-caspase inhibitor z-VAD-FMK. Mitochondrial membrane potential (ΔΨm) dysfunction was analyzed by JC-1 staining, whereas reactive oxygen species (ROS) generation was confirmed by pretreatment with N-acetylcysteine (NAC) and fluorogenic probe-based flow cytometric detection. The expression of cell cycle regulatory proteins, apoptotic proteins and MAPK signaling molecules was determined by Western blotting. Involvement of JNK, p38-MAPK and MEK/ERK in ROS-mediated apoptosis was investigated by pretreatment with SP600125 (JNK inhibitor), SB203580 (p38 inhibitor) and U0126 (ERK1/2 inhibitor), respectively. The stemness-targeting potential of Sng was assessed in tumor cell-derived spheroids. RESULTS: Treatment with Sng decreased cell viability and colony formation in primary (A431) and metastatic (A388) cSCC cells in a time- and dose-dependent manner. Sng significantly inhibited cell proliferation by inducing sub-G0/G1 cell-cycle arrest and apoptosis in cSCC cells. Sng evoked ROS generation, intracellular glutathione (GSH) depletion, ΔΨm depolarization and the activation of JNK pathway as well as that of caspase-3, -8, -9, and PARP. Antioxidant NAC inhibited ROS production, replenished GSH levels, and abolished apoptosis induced by Sng by downregulating JNK. Pretreatment with z-VAD-FMK inhibited Sng-mediated apoptosis. The pharmacological inhibition of JNK by SP600125 mitigated Sng-induced apoptosis in metastatic cSCC cells. Finally, Sng ablated the stemness of metastatic cSCC cell-derived spheroids. CONCLUSION: Our results indicate that Sng exerts a potent cytotoxic effect against cSCC cells that is underscored by a mechanism involving multiple levels of cooperation, including cell-cycle sub-G0/G1 arrest and apoptosis induction through ROS-dependent activation of the JNK signaling pathway. This study provides insight into the potential therapeutic application of Sng targeting cSCC.

The role of mitochondrial reactive oxygen species in chondrocyte mechanotransduction.

Chondrocytes are mechanosensitive cells able to sense and respond to external mechanical stimuli through the process of mechanotransduction. Previous studies have demonstrated that mechanical stimulation causes mitochondrial deformation leading to mitochondrial reactive oxygen species (ROS) release in a dose-dependent manner. For this reason, we focused on elucidating the role of mitochondrial ROS as anabolic signaling molecules in chondrocyte mechanotransduction. Chondrocyte-seeded agarose gels were subjected to mechanical stimuli and the effect on matrix synthesis, ROS production, and mitogen-activated protein kinases (MAPK) signaling was evaluated. Through the use of ROS-specific staining, superoxide anion was the primary ROS released in response to mechanical stimuli. The anabolic effect of mechanical stimulation was abolished in the presence of electron transport chain inhibitors (complexes I, III, and V) and superoxide anion scavengers. Subsequent studies were centered on the involvement of MAPK pathways (ERK1/2, p38, and JNK) in the mechanotransduction cascade. While disruption of the ERK1/2 pathway had no apparent effect, the anabolic effect of mechanical stimulation was abolished in the presence of p38 and JNK pathway inhibitors. This suggest the involvement of apoptosis stimulating kinase 1 (ASK1), an upstream redox-sensitive MAP3K shared by both the JNK and p38 pathways. Future experiments will focus on the involvement of the thioredoxin-ASK1 complex which disassociates in the presence of oxidative stress, allowing ASK1 to phosphorylate several MAP2Ks. Overall, these findings indicate superoxide anion as the primary ROS released in response to mechanical stimuli and that the resulting anabolic effect on chondrogenic matrix biosynthesis arises from the ROS-dependent activation of the p38 and JNK MAPKs.

Selenium-Chitosan Protects Porcine Endometrial Epithelial Cells from Zearalenone-induced Apoptosis via the JNK/SAPK Signaling Pathway.

This study was designed to assess whether selenium-chitosan (Se-CTS) can protect porcine endometrial epithelial cells (PEECs) against damage and apoptosis induced by zearalenone (ZEA) via modulating the JNK/SAPK signaling pathway. The cell cycle, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and apoptosis rates of porcine endometrial epithelial cells were determined, as well as the expression levels of genes related to the SAPK/JNK signaling pathway. The results showed that 3.0 µmol/L Se-CTS decreased the percentage of ZEA-induced G1 phase in PEECs (P < 0.01), whereas 1.5 and 3.0 µmol/L Se-CTS increased the percentage of ZEA-induced percentage of G2 phase of PEECs (P < 0.01). Further, Se-CTS at 1.5 and 3.0 µmol/L improved the ZEA-induced decrease in MMP (P < 0.01), whereas Se-CTS at 0.5, 1.5, and 3.0 µmol/L reduced the increase in ROS levels and apoptosis rate induced by ZEA in PEECs (P < 0.01 or P < 0.05). Furthermore, 3.0 µmol/L Se-CTS ameliorated the increase in the expression of c-Jun N-terminal kinase (JNK), apoptosis signal-regulated kinase (ASK1), and c-Jun induced by ZEA (P < 0.01) and the reduction in mitogen-activated protein kinase kinase 4 (MKK4) and protein 53 (p53) expression (P < 0.01), while 1.5 µmol/L Se-CTS improved the expression of ASK1 and c-Jun induced by ZEA (P < 0.05). The results proved that Se-CTS alleviates ZEA-induced cell cycle stagnation, cell mitochondrial damage, and cell apoptosis via decreasing ZEA-produced ROS and modulating the JNK/SAPK signaling pathway.

Sesamin attenuates UVA-induced keratinocyte injury via inhibiting ASK-1-JNK/p38 MAPK pathways.

BACKGROUND: Ultraviolet (UV) exposure-stimulated reactive oxygen species (ROS) formation in keratinocytes is a crucial factor in skin aging. Phytochemicals have become widely popular for protecting the skin from UV-induced cell injury. Sesamin (SSM) has been shown to play a role in extensive pharmacological activity and exhibit photoprotective effects. AIM: To assess the protective effect of SSM on UVA-irradiated keratinocytes and determine its potential antiphotoaging effect. METHODS: HaCaT keratinocytes pretreated with SSM were exposed to UVA radiation at 8 J/cm2 for 10 min. Cell viability and oxidative stress indicators were evaluated using a cell counting kit-8 and lactate dehydrogenase (LDH), malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) assay kits. Apoptosis and intracellular ROS levels were analyzed using annexin V-fluorescein isothiocyanate/propyridine iodide and dichlorodihydrofluorescein diacetate staining, respectively. Protein levels of matrix metalloprotein-1 (MMP-1), MMP-9, Bax/Bcl-2, and mitogen-activated protein kinase (MAPK) pathway proteins, phospho-apoptosis signal-regulating kinase-1 (p-ASK-1)/ASK-1, phospho-c-Jun N-terminal protein kinase (p-JNK)/JNK, and p-p38/p38 were determined using western blotting. RESULTS: Sesamin showed no cytotoxicity until 160 µmol/L on human keratinocytes. Sesamin pretreatment (20 and 40 µM) reversed the suppressed cell viability, increased LDH release and MDA content, decreased cellular antioxidants GSH and SOD, and elevated intracellular ROS levels, which were induced by UVA irradiation. Additionally, SSM inhibited the expression of Bax, MMP-1, and MMP-9 and stimulated Bcl-2 expression. In terms of the regulatory mechanisms, we demonstrated that SSM inhibits the phosphorylation of ASK-1, JNK, and p38. CONCLUSION: The results suggest that SSM attenuates UVA-induced keratinocyte injury by inhibiting the ASK-1-JNK/p38 MAPK pathways.

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.

Mechanisms underlying sensing of cellular stress signals by mammalian MAP3 kinases.

Cellular homeostasis is continuously challenged by environmental cues and cellular stress conditions. In their defense, cells need to mount appropriate stress responses that, dependent on the cellular context, signaling intensity, and duration, may have diverse outcomes. The stress- and mitogen-activated protein kinase (SAPK/MAPK) system consists of well-characterized signaling cascades that sense and transduce an array of different stress stimuli into biological responses. However, the physical and chemical nature of stress signals and how these are sensed by individual upstream MAP kinase kinase kinases (MAP3Ks) remain largely ambiguous. Here, we review the existing knowledge of how individual members of the large and diverse group of MAP3Ks sense specific stress signals through largely non-redundant mechanisms. We emphasize the large knowledge gaps in assigning function and stress signals for individual MAP3K family members and touch on the potential of targeting this class of proteins for clinical benefit.