c-Jun N-terminal Kinase Signaling Research Articles

Propofol protects human cardiac AC16 cells from CoCl2-induced hypoxic injury

To explore the effect of propofol on human cardiac AC16 cells under CoCl2-induced hypoxic injury and the possible mechanisms. Methods: Human AC16 cardiomyocytes were treated with cobalt chloride (CoCl2) to mimic hypoxic condition in cultured cardiomyocytes. The AC16 cells were divided into 3 groups: a control group, a CoCl2 hypoxia group (CoCl2 group), and a propofol+CoCl2 group (propofol+ CoCl2 group). The cell viability was assessed by cell counting kit-8 (CCK-8). Cell apoptosis ratio (AR) and the mitochondrial membrane potential (Δψm) were detected by flow cytometry. The reactive oxygen species (ROS) production in AC16 cells were determined with the ROS-sensitive fluorescent probe. Meanwhile, total intracellular levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in AC16 cells were detected with commercially available kits. Western blot was used to evaluate the activation of c-Jun N-terminal kinase (JNK) and p38 signaling pathways. Results: 1) Compared with the control group, AC16 cell viability was decreased significantly in the CoCl2 group following the treatment with 500 μmol/L CoCl2 (P<0.01); 2) Compared with the control group, AR value in AC16 cells was increased significantly in the CoCl2 group, while Δψm was decreased significantly (all P<0.01). Compared with the CoCl2 group, AR value in AC16 cells was decreased significantly in the propofol+CoCl2 group, while Δψm was increased significantly (both P<0.05); 3) Compared with the control group, the levels of ROS and MDA were increased significantly, and the level of SOD was significantly decreased in the CoCl2 group (all P<0.01). Compared with the CoCl2 group, the ROS and MDA levels in the propofol+CoCl2 group were increased significantly and the SOD levels were decreased significantly (all P<0.05); 4) Compared with the control group, the phosphorylation levels of JNK and p38 were increased significantly (both P<0.05) in the CoCl2 group. Compared with the CoCl2 group, the phosphorylation levels of JNK and p38 were decreased significantly in the propofol+CoCl2 group (both P<0.05). Conclusion: The pretreatment with propofol may protect human cardiac AC16 cells from the chemical hypoxia-induced injury through regulation of JNK and p38 signaling pathways.

Treatment With the Delta Opioid Agonist UFP-512 Alleviates Chronic Inflammatory and Neuropathic Pain: Mechanisms Implicated.

We investigated whether administration of the δ-opioid receptor (DOR) agonist H-Dmt-Tic-NH-CH(CH2-COOH)-Bid (UFP-512), which also activates nuclear factor erythroid 2-related factor 2 (Nrf2), alleviated chronic inflammatory and/or neuropathic pain and inhibited the depressive-like behaviors associated with persistent neuropathic pain. The possible mechanisms implicated were also assessed. We evaluated the following effects in male C57BL/6J mice with inflammatory pain induced by complete Freund’s adjuvant or neuropathic pain caused by the chronic constriction of sciatic nerve: (1) the antinociceptive effects of UFP-512; (2) the effects of UFP-512 on the expression of Nrf2, heme oxygenase 1 (HO-1), NAD(P)H quinone oxidoreductase 1, phosphoinositide 3-kinase (PI3K), protein kinase B (Akt), inducible nitric oxide synthase, DOR, and mitogen-activated protein kinases (MAPK) in the spinal cord of animals with inflammatory or neuropathic pain; (3) the antinociceptive effects of the coadministration of UFP-512 with the Nrf2 activator sulforaphane (SFN); and (4) the antidepressant effects of UFP-512 in animals with depressive-like behaviors associated with neuropathic pain. Our results demonstrated that the intraperitoneal administration of UFP-512 inhibited chronic inflammatory and neuropathic pain and reduced the depressive-like behaviors associated with persistent neuropathic pain. The antiallodynic effects of UFP-512 were significantly augmented when it was coadministered with SFN in both types of chronic pain. The administration of UFP-512 increased/reestablished the spinal cord protein levels of Nrf2 and HO-1 in mice with inflammatory or neuropathic pain. However, while during inflammatory pain UFP-512 inhibited spinal c-Jun N-terminal kinase (JNK) and extracellular signal regulated kinase 1/2 (ERK1/2) phosphorylation induced by peripheral inflammation. This DOR agonist blocked the spinal activated PI3K/Akt signaling pathway under chronic neuropathic pain conditions, but it did not alter the enhanced protein levels of p-JNK or p-ERK1/2 induced by sciatic nerve injury. These results revealed the antinociceptive and antidepressant effects of UFP-512 in animals with chronic pain and the different mechanism of action of this DOR agonist in the presence of inflammatory or neuropathic pain. Our data also suggest the administration of UFP-512 as an alternative for the treatment of chronic pain and the depressive-like behaviors associated with neuropathic pain.

Negative pressure wound therapy promoted wound healing by suppressing inflammation via down-regulating MAPK-JNK signaling pathway in diabetic foot patients

AimsNegative pressure wound therapy displayed significant clinical benefits in the healing of diabetic foot wounds. In the present study, we investigated the mechanism of regulation of MAPK-JNK (Mitogen-activated protein kinase- c-Jun N-terminal kinase) signaling pathway by negative pressure wound therapy on these wounds. MethodsTwenty-six type 2 diabetes patients with foot ulceration were randomly assigned to the two groups, thirteen treated with negative pressure wound therapy and the others treated with traditional debridement therapy. Skin samples were harvested and histologically and immunohistochemical analyzed in both groups. Immunofluorescence stain, Enzyme-linked immunosorbent assay and Western blotting were performed for inducible nitric oxide synthase, inter leukin-6, tumor necrosis factor-α, P-c-Jun N-terminal kinase and c-Jun N-terminal kinase. Real time-polymerase chain reaction was performed to evaluate expression of c-Jun N-terminal kinase, extracellular signal regulated kinase1/2 and p38. ResultsNegative pressure wound therapy could effectively alleviate inflammatory reaction and reduce inter leukin-6 and inducible nitric oxide synthase production after 7 days treatment. The level of tumor necrosis factor-α, inter leukin-6 and P-c-Jun N-terminal kinase were significantly decreased. However, there was no statistical difference in messenger ribonucleic acid expression of p38, extracellular signal regulated kinase1 and 2. ConclusionsNegative pressure wound therapy possibly suppress the wound inflammation by inhibiting inter leukin-6, tumor necrosis factor-α and inducible nitric oxide synthase in diabetic foot patients. This effect is maybe mediated at least in part by suppression of Mitogen-activated protein kinase- c-Jun N-terminal kinase signaling pathway.

Cadmium-induced apoptosis through reactive oxygen species-mediated mitochondrial oxidative stress and the JNK signaling pathway in TM3 cells, a model of mouse Leydig cells

Cadmium (Cd) is a heavy metal that widely exists in the environment and industry, and which causes serious damages to reproductive system. Recent studies have reported that cadmium induces apoptosis of various germ cells in testes, resulting in male infertility. However, the exact mechanism of cadmium-induced apoptosis remains unclear. In this study, we hypothesized that reactive oxygen species (ROS)-mediated c-jun N-terminal kinase (JNK) signaling pathway was involved in cadmium-induced apoptosis in TM3 cells, a model of mouse Leydig cells. TM3 cells were exposed for various times to a range of cadmium concentrations. We found that cadmium reduced TM3 cell viability and increased apoptosis in a time- and dose- dependent manner. Moreover, the levels of ROS generation and the phosphorylation of JNK were elevated by cadmium treatment. In addition, the nuclear transcription factor c-jun was significantly activated, which led to increased expression of downstream c-jun targets and Bcl-2 was decreased, accompanied with downstream activation of apoptosis-related proteins such as Cleaved-Caspase3 and Cleaved-PARP. However, pretreatment with the ROS inhibitor N-acetyl-L-cysteine (NAC) and JNK inhibitor JNK-IN-8, ROS, JNK and cadmium-induced TM3 cell apoptosis were remarkably suppressed. Based on above-mentioned results, this study provides a mechanistic understanding of cadmium induced TM3 cell apoptosis through the ROS/JNK signaling pathways.

Role of FOXO3 Activated by HIV-1 Tat in HIV-Associated Neurocognitive Disorder Neuronal Apoptosis.

There are numerous types of pathological changes in human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND), including apoptosis of neurons. HIV-1 transactivator of transcription (Tat) protein, which is encoded by HIV-1, may promote apoptosis in HAND. Forkhead box O3 (FOXO3) is a multispecific transcription factor that has roles in many biological processes, including cellular apoptosis. The aim of this study was to determine whether FOXO3 is activated by HIV-1 Tat and to investigate its role in neuronal apoptosis in HAND. We employed tissue staining and related molecular biological experimental methods to confirm our hypothesis. The in vivo experimental results demonstrated that the expression of nuclear FOXO3 increased in the apoptotic neurons of the cerebral cortexes of rhesus macaques infected with simian human immunodeficiency virus (SHIV). The in vitro investigation showed that HIV-1 Tat activated FOXO3, causing it to move from the cytoplasm to the nucleus via the c-Jun N-terminal kinase (JNK) signaling pathway in SH-SY5Y cells. Moreover, FOXO3 down-regulated expression of the anti-apoptosis gene B-cell lymphoma 2 (Bcl-2) and up-regulated the expression of the pro-apoptosis gene Bcl-2-like 11 (Bim) after entering the nucleus, eventually causing cellular apoptosis. Finally, reduction of nuclear FOXO3 reversed cellular apoptosis. Our results suggest that HIV-1 Tat induces FOXO3 to translocate from the cytoplasm to the nucleus via the JNK signaling pathway, leading to neuronal apoptosis. Agents targeting FOXO3 may provide approaches for restoring neuronal function in HAND.

Structure-Guided Development of Dual Inhibitors of EGFR and JNK to Treat GBM and NSCLC

Abnormal epidermal growth factor receptor (EGFR) signaling is widespread in cancer, making the EGFR as an important target for therapy. The third-generation EGFR small-molecule inhibitors are at the forefront clinically for treatment of patients with non-small cell lung cancer (NSCLC). However, acquired resistance limits the effectiveness. The c-Jun N-terminal kinase (JNK) signaling axis mediates primary resistance to EGFR inhibition in glioblastoma (GBM) and NSCLC. Therefore, it's a new approach of using a dual EGFR and JNK inhibition to treat EGFR-expressing GBM and NSCLC is a new approach. On the basis of an iterative approach of docking, two series of trisubstituted 1,2,4-triazoles and thiazoles were designed and synthesized. Some compounds demonstrated inhibitory activity for EGFR and JNK kinases with IC50 values in the low nanomolar range. This work may lead to design and optimize the potent EGFR and JNK inhibitors in the future.

Forskolin exerts anticancer roles in non-Hodgkin's lymphomas via regulating Axin/β-catenin signaling pathway.

BackgroundNon-Hodgkin’s lymphomas (NHLs) account for 85% of lymphomas, which are characterized by high-degree malignancy, rapid progress, and even invasion into central nervous system in pediatric patients. Although the cure rate of pediatric NHL has improved, some patients have still underwent recurrence or death. This study focuses on the effects and mechanism of forskolin on the progression of NHL, aiming to find efficient therapy methods for pediatric NHL.MethodsMTT, flow cytometry and mice tumor bearing experiments were used to evaluate the effects of forskolin on NHL cell proliferation, apoptosis and tumorigenesis. Western blotting and RT-PCR assays were used to detect protein and mRNA expression. Immunohistochemistry technology was recruited to analyze Ki-67 expression in tumor tissues.ResultsForskolin significantly increased the expression of cleaved caspase-3/9 in both NHL Toledo and NK-92 cell lines, and inhibited cell growth. Besides, forskolin obviously reduced the expression of β-catenin protein, promoted its ubiquitination, enhanced its transportation from nuclear to cytoplasm, as well as decreased the expression of its downstream oncogenes c-myc and cyclin D1 through upregulating Axin expression and stability and inhibiting Axin ubiquitination. Moreover, forskolin enhanced the effects of SP600125, an inhibitor of c-Jun N-terminal kinase signaling on cell apoptosis promotion and tumorigenesis inhibition via Axin-induced β-catenin signaling repression.ConclusionThe current study clarifies that forskolin can inhibit the progression of NHL through Axin-mediated inhibition of β-catenin signaling. Moreover, forskolin improves the effects of SP600125 on cell apoptosis enhancement and tumorigenesis inhibition of NHL cells. These findings provide theoretical foundation of serving forskolin as a new effective therapeutic drug for pediatric NHL.

Clostridium perfringens \u03b1-toxin impairs granulocyte colony-stimulating factor receptor-mediated granulocyte production while triggering septic shock

During bacterial infection, granulocyte colony-stimulating factor (G-CSF) is produced and accelerates neutrophil production from their progenitors. This process, termed granulopoiesis, strengthens host defense, but Clostridium perfringens α-toxin impairs granulopoiesis via an unknown mechanism. Here, we tested whether G-CSF accounts for the α-toxin-mediated impairment of granulopoiesis. We find that α-toxin dramatically accelerates G-CSF production from endothelial cells in response to Toll-like receptor 2 (TLR2) agonists through activation of the c-Jun N-terminal kinase (JNK) signaling pathway. Meanwhile, α-toxin inhibits G-CSF-mediated cell proliferation of Ly-6G+ neutrophils by inducing degradation of G-CSF receptor (G-CSFR). During sepsis, administration of α-toxin promotes lethality and tissue injury accompanied by accelerated production of inflammatory cytokines in a TLR4-dependent manner. Together, our results illustrate that α-toxin disturbs G-CSF-mediated granulopoiesis by reducing the expression of G-CSFR on neutrophils while augmenting septic shock due to excess inflammatory cytokine release, which provides a new mechanism to explain how pathogenic bacteria modulate the host immune system.

Sirtuin 3 inhibition induces mitochondrial stress in tongue cancer by targeting mitochondrial fission and the JNK-Fis1 biological axis.

Sirtuin 3 (Sirt3)-modified mitochondrial fission participates in the progression of several types of cancers. However, its role in tongue cancer requires investigation. The aim of our study is to determine whether Sirt3 knockdown regulates the viability of tongue cancer cells via modulating mitochondrial fission. Two types of tongue cancer cells were used in the present study, and siRNA was transfected into the cells to suppress Sirt3 expression. Mitochondrial function and cell apoptosis were determined via immunofluorescence, Western blotting, ELISA, and qPCR assays. A pathway blocker was applied to verify the role of the JNK-Fis1 signaling pathway in regulation of mitochondrial fission. The present study showed that loss of Sirt3 promoted tongue cancer cell death in a manner dependent on mitochondrial apoptosis. Mitochondrial oxidative stress, energy metabolism disorder, mitochondrial cyt-c liberation, and mitochondrial apoptosis activation were observed after Sirt3 silencing. Furthermore, we demonstrated that Sirt3 knockdown activated mitochondrial stress via triggering Fis1-related mitochondrial fission and that inhibition of Fis1-related mitochondrial fission abrogated the pro-apoptotic effect of Sirt3 knockdown on tongue cancer cells. To this end, we found that Sirt3 modulated Fis1 expression via the c-Jun N-terminal kinases (JNK) signaling pathway and that blockade of the JNK pathway attenuated mitochondrial stress and repressed apoptosis in Sirt3 knockdown cells. Altogether, our results identified a tumor-suppressive role for Sirt3 deficiency in tongue cancer via activation of the JNK-Fis1 axis and subsequent initiation of fatal mitochondrial fission. Given these findings, strategies to repress Sirt3 activity and enhance the JNK-Fis1-mitochondrial fission cascade have clinical benefits for patients with tongue cancer.

Phorbol ester-induced angiogenesis of endothelial progenitor cells: The role of NADPH oxidase-mediated, redox-related matrix metalloproteinase pathways.

Endothelial progenitor cells (EPCs) may contribute to ischemia-induced angiogenesis in atherosclerotic diseases. The protein kinase C (PKC) family is involved in the regulation of angiogenesis, however the role of PKCα in EPCs during angiogenesis is unclear. The aim of this study was to evaluate the role of PKCα in EPCs during angiogenesis. Phorbol-12-myristate-13-acetate (PMA), a PKCα activator, significantly increased the activity and expression of matrix metalloproteinases (MMP) -2 and -9 in human (late outgrowth) EPCs in vitro. The MMPs promoted the migratory function and vascular formation of EPCs, which then contributed to neovascularization in a mouse hindlimb-ischemia model. Reactive oxygen species derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enhanced the expression of MMPs to increase the bioactivity of EPCs during angiogenesis. The mitogen-activated protein kinase (MAPK) signal pathway was associated with the activation of NADPH oxidase. PMA extensively activated the extracellular signal–regulated kinase (Erk) signal pathway to increase the expression of MMP-9. PMA also activated the p38, Erk, and c-Jun N-terminal kinase signal pathways to increase the expression of MMP-2. PMA-stimulated EPCs enhanced neovascularization in a mouse model of hindlimb ischemia via nuclear factor-κB translocation to up-regulation of the expression of MMP-2 and MMP-9. PMA could activate PKCα and promote the angiogenesis capacity of human EPCs via NADPH oxidase-mediated, redox-related, MMP-2 and MMP-9 pathways. The PKCα-activated, NADPH oxidase-mediated, redox-related MMP pathways could contribute to the function of human EPCs for ischemia-induced neovascularization, which may provide novel insights into the potential modification of EPCs for therapeutic angiogenesis.

Dexmedetomidine improves acute stress-induced liver injury in rats by regulating MKP-1, inhibiting NF-κB pathway and cell apoptosis.

Acute stress is a frequent and unpredictable disease for many animals. Stress is widely considered to affect liver function. However, the underlying mechanism by which dexmedetomidine (DEX) attenuates acute stress-induced liver injury in rats remains unclear. In this study, we used forced swimming for 15 min and acute 3-hr restraint stress model. Behavioral tests and changes in norepinephrine levels confirmed the successful establishment of the acute stress model. Acute stress-induced liver injury, evidenced by hematoxylin and eosin-stained pathological sections and increased serum aminotransferase and aspartate aminotransferase levels, was reduced in DEX-treated livers. Reactive oxygen species and oxidative stress levels were dramatically decreased with DEX treatment compared with acute stress-induced liver injury. DEX significantly reduced acute stress-induced liver inflammation and apoptosis, as assessed by terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and inflammation and apoptosis-related protein levels. DEX treatment also effectively inhibited acute stress-induced c-Jun N-terminal kinase (JNK), P38, and BAD signaling pathway activation, and significantly induced MKP-1 activation. Thus, DEX has a protective effect on acute-stress-induced liver injury by reducing inflammation and apoptosis, which suggests a potential clinical application for DEX in stress syndrome.

Autophagy triggered by MAVS inhibits Coxsackievirus A16 replication.

Mitochondrial antiviral signaling protein (MAVS), a crucial adaptor protein localized on mitochondria, plays vital roles in various biological processes. Autophagy and apoptosis are two independent and closely linked cell death pathways. But whether MAVS could induce apoptosis and autophagy in rhabdomyosarcoma cells (RD cells) and what is the relationship between autophagy and apoptosis still remains elusive. Here, we reveal that overexpression of MAVS could trigger both apoptosis and autophagy in RD cells. Interestingly, MAVS-induced apoptosis was dependent on the activation of the c-Jun N-terminal kinase (JNK) signaling pathway and inhibition of the extracellular signal-regulated kinase (ERK) signaling pathway. Also, it was found that inhibition of autophagy by 3-methyladenine (3-MA) enhanced MAVS-induced apoptosis resulting in increased cleavage of caspase-3 and poly (ADP-ribose) polymerase (PARP). Meanwhile, autophagy induction by rapamycin resulted in decreased MAVS-induced apoptosis. In addition, we found that MAVS expression was inhibited upon Coxsackievirus A16 (CA16) infection and overexpression of MAVS could inhibit CA16 replication. Collectively, our study provides novel insights into the link between apoptosis and autophagy induced by MAVS overexpression in RD cells and gains a greater understanding of MAVS-induced antiviral functions, which provide new targets for CA16 treatment. Keywords: CA16; MAVS; apoptosis; autophagy.

MEKK3 coordinates with FBW7 to regulate WDR62 stability and neurogenesis.

Mutations of WD repeat domain 62 (WDR62) lead to autosomal recessive primary microcephaly (MCPH), and down-regulation of WDR62 expression causes the loss of neural progenitor cells (NPCs). However, how WDR62 is regulated and hence controls neurogenesis and brain size remains elusive. Here, we demonstrate that mitogen-activated protein kinase kinase kinase 3 (MEKK3) forms a complex with WDR62 to promote c-Jun N-terminal kinase (JNK) signaling synergistically in the control of neurogenesis. The deletion of Mekk3, Wdr62, or Jnk1 resulted in phenocopied defects, including premature NPC differentiation. We further showed that WDR62 protein is positively regulated by MEKK3 and JNK1 in the developing brain and that the defects of wdr62 deficiency can be rescued by the transgenic expression of JNK1. Meanwhile, WDR62 is also negatively regulated by T1053 phosphorylation, leading to the recruitment of F-box and WD repeat domain-containing protein 7 (FBW7) and proteasomal degradation. Our findings demonstrate that the coordinated reciprocal and bidirectional regulation among MEKK3, FBW7, WDR62, and JNK1, is required for fine-tuned JNK signaling for the control of balanced NPC self-renewal and differentiation during cortical development.

Chrysanthemulide A induces apoptosis through DR5 upregulation via JNK-mediated autophagosome accumulation in human osteosarcoma cells.

Osteosarcoma is the most frequent malignant primary bone tumor, and it generally develops a multidrug resistance. Chrysanthemulide A (CA) is a sesquiterpenoid from the herb Chrysanthemum indicum that has demonstrated a great anti-osteosarcoma potential. In this study, CA-induced apoptotic cell death resulted in the activation of the caspase-8-mediated caspase cascade, as evidenced by the cleavage of the substrate protein Bid and the caspase-8 inhibitor Z-VAD-FMK. The CA treatment upregulated the expression of death receptor 5 (DR5) in both whole cells and the cell membrane. Blocking DR5 expression by the small interfering RNA (siRNA) treatment decreased the caspase-8-mediated caspase cascade and efficiently attenuated CA-induced apoptosis, suggesting the critical role of DR5 in CA-induced apoptotic cell death. CA-induced upregulation of the DR5 protein was accompanied by the accumulation of LC3B-II, indicating the formation of autophagosomes. Importantly, DR5 upregulation was mediated by transcriptionally controlled autophagosome accumulation, as blockade of autophagosomes by LC3B or ATG-5 siRNA substantially decreased DR5 upregulation. Furthermore, CA activated the c-Jun N-terminal kinase (JNK) signaling pathway, and treatment with JNK siRNAs or inhibitor SP600125 significantly attenuated CA-mediated autophagosome accumulation and DR5-mediated cell apoptosis. Finally, CA sensitized the osteosarcoma cells to the DR5 ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptotic cell death. Above all, these results suggest that CA induces apoptosis through upregulating DR5 via JNK-mediated autophagosome accumulation and that combined treatment with CA and TRAIL might be a promising therapy for osteosarcoma.

Ginsenoside metabolite compound K induces apoptosis and autophagy in non-small cell lung cancer cells via AMPK-mTOR and JNK pathways.

Compound K [C-K; 20-O-(β-d-glucopyranosyl)-20(S)-protopanaxadiol], as a metabolite of ginsenoside, has been verified to have antitumor effects in various cancers, including non-small cell lung cancer (NSCLC). However, the detailed mechanisms of C-K in NSCLC remain largely unknown. In this study, we aimed to evaluate the effect of C-K on apoptosis and autophagy in NSCLC cells as well as its related mechanisms. According to the results, C-K suppressed the proliferation, and led to G1 phase arrest and apoptosis in A549 and H1975 cells. Subsequently, C-K promoted autophagy, as confirmed by the enhanced rate of cells staining positive with acridine orange, increased levels of LC3II and Beclin-1, and with decreased levels of p62 in A549 and H1975 cells. Moreover, 3-methyladenine (3-MA; an inhibitor of autophagy) effectively suppressed the inhibition of proliferation and apoptosis that was induced with C-K. Finally, C-K treatment promoted the activation of the AMPK-mTOR and c-Jun N-terminal kinase (JNK) signaling pathways. Treatment with compound C (AMPK inhibitor) or SP600125 (JNK inhibitor) significantly restrained the inhibition of proliferation, apoptosis, and autophagy induced with C-K in A549 and H1975 cells. In conclusion, this study demonstrates that C-K promotes autophagy-mediated apoptosis in NSCLC via AMPK-mTOR and JNK signaling pathways.

Constrained-induced movement therapy promotes motor function recovery by enhancing the remodeling of ipsilesional corticospinal tract in rats after stroke

Constraint-induced movement therapy (CIMT), which forces the use of the impaired limb by restraining the unaffected limb, has been used extensively for the recovery of limb motor function after stroke. However, the underlying mechanism of CIMT remains unclear. Diffusion tensor imaging (DTI) is a well-known neuroimaging technique that reflects the microstructure of white matter tracts and potential changes associated with different treatments. The aim of this study is to use DTI imaging to determine how corticospinal tract (CST) fibers remodel in ischemic rats with CIMT. In the present study, rats were randomly divided into three groups: a middle cerebral artery occlusion group (MCAO), a therapeutic group (MCAO + CIMT), and a sham-operated group (sham). A plaster cast was used to restrict the unaffected limb of the rats in the MCAO + CIMT group for 14 days. The Catwalk system was used to assess the limb motor function of rats. Fractional anisotropy (FA) and the average diffusion coefficient (ADC) of the CST were quantified through DTI. The expression of the c-Jun–N-terminal kinase signaling pathway (JNK) was examined after 14 days of CIMT. We found that CIMT could accelerate and enhance motor function recovery, and the MCAO + CIMT group showed significantly increased FA values in the ipsilesional posterior limb of internal capsule (PLIC) compared with the MCAO group. In addition, we found no significant difference in the ratio of phosphorylated-JNK/total-JNK among the three groups, whereas the expression of P-JNK decreased significantly in the chronic phase of stroke. In conclusion, CIMT-induced functional recovery following ischemic stroke through facilitation of the remodeling of ipsilesional CST, and restoration after ischemic stroke may be associated with the declining value of the ratio of P-JNK/JNK.

Synergistic anticancer effects of timosaponin AIII and ginsenosides in MG63 human osteosarcoma cells

BackgroundTimosaponin AIII (TA3) is a steroidal saponin extracted from Anemarrhena asphodeloides. Here, we investigated the anticancer effects of TA3 in MG63 human osteosarcoma cells. TA3 attenuates migration and invasion of MG63 cells via regulations of two matrix metalloproteinases (MMPs), MMP-2 and MMP-9, which are involved with cancer metastasis in various cancer cells. TA3 reduced enzymatic activities and transcriptional expressions of MMP-2 and MMP-9 in MG63 cells. TA3 also inhibited Src, focal adhesion kinase, extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), p38, β-catenin, and cAMP response element binding signaling, which regulate migration and invasion of cells. TA3 induced apoptosis of MG63 cells via regulations of caspase-3, caspase-7, and poly(ADP-ribose) polymerase (PARP). Then, we tested several ginsenosides to be used in combination with TA3 for the synergistic anticancer effects. We found that ginsenosides Rb1 and Rc have synergistic effects on TA3-induced apoptosis in MG63 cells. MethodsWe investigated the anticancer effects of TA3 and synergistic effects of various ginseng saponins on TA3-induced apoptosis in MG63 cells. To test antimetastatic effects, we performed wound healing migration assay, Boyden chamber invasion assays, gelatin zymography assay, and Western blot analysis. Annexin V/PI staining apoptosis assay was performed to determine the apoptotic effect of TA3 and ginsenosides. ResultsTA3 attenuated migration and invasion of MG63 cells and induced apoptosis of MG63 cells. Ginsenosides Rb1 and Rc showed the synergistic effects on TA3-induced apoptosis in MG63 cells. ConclusionsThe results strongly suggest that the combination of TA3 and the two ginsenosides Rb1 and Rc may be a strong candidate for the effective antiosteosarcoma agent.

Mitigation Effects of a Novel Herbal Medicine, Hepad, on Neuroinflammation, Neuroapoptosis, and Neuro-Oxidation.

Parkinson’s disease (PD), a common adult-onset neurodegenerative disorder with complex pathological mechanisms, is characterized by the degeneration of dopaminergic nigrostriatal neurons. The present study demonstrated that the herbal medicines Hepad 1 and 2 protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurotoxicity in C57BL/6 mice and SH-SY5Y cells. Hepad 1 and 2 remarkably alleviated the enhanced expression of pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, cyclooxygenase-2, macrophage-1, and phosphorylated iκB-α) and apoptotic signals (Bcl-2-associated X protein, caspase-3, and poly [ADP-ribose] polymerase-1). Additionally, Hepad reduced MPTP-induced oxidative damage by increasing the expression of anti-oxidant defense enzymes (superoxide dismutase and glutathione S-transferase) and downregulating the levels of nicotinamide adenine dinucleotide phosphate oxidase 4. This study also showed that the neuroprotective effects of Hepad include anti-inflammatory, anti-apoptotic, and anti-oxidative properties, in addition to activation of the protein kinase B, extracellular-signal-regulated kinase, and c-Jun N-terminal kinase signaling pathways. Furthermore, oral administration of Hepad 1 and 2 attenuated the death of tyrosine hydroxylase-positive substantia nigra neurons that was induced by 20 mg/kg MPTP. Therefore, our results suggest that Hepad 1 and 2 are useful for treating PD and other disorders associated with neuro-inflammatory, neuro-apoptotic, and neuro-oxidative damage.

Prenylated quinolinecarboxylic acid derivative prevents neuronal cell death through inhibition of MKK4

The development of neuroprotective agents is necessary for the treatment of neurodegenerative diseases. Here, we report PQA-11, a prenylated quinolinecarboxylic acid (PQA) derivative, as a potent neuroprotectant. PQA-11 inhibits glutamate-induced cell death and caspase-3 activation in hippocampal cultures, as well as inhibits N-Methyl-4-phenylpyridinium iodide- and amyloid β1-42-induced cell death in SH-SY5Y cells. PQA-11 also suppresses mitogen-activated protein kinase kinase 4 (MKK4) and c-jun N-terminal kinase (JNK) signaling activated by these neurotoxins. Quartz crystal microbalance analysis and in vitro kinase assay reveal that PQA-11 interacts with MKK4, and inhibits its sphingosine-induced activation. The administration of PQA-11 by intraperitoneal injection alleviates 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced degeneration of nigrostriatal dopaminergic neurons in mice. These results suggest that PQA-11 is a unique MKK4 inhibitor with potent neuroprotective effects in vitro and in vivo. PQA-11 may be a valuable lead for the development of novel neuroprotectants.

The Stress c-Jun N-terminal Kinase Signaling Pathway Activation Correlates with Synaptic Pathology and Presents A Sex Bias in P301L Mouse Model of Tauopathy

Pathological Tau (P-Tau) leads to dementia and neurodegeneration in tauopathies, including Alzheimer’s disease. The P301L transgenic mice well mimic human tauopathy features; P-Tau localizes also at the dendritic spine level and this correlates with synaptic markers down-regulation. Importantly, tg females present a more severe pathology compared to male mice. We describe JNK activation in P301L-tg mice, characterizing by P-JNK and P-c-Jun, cleaved-Caspase-3, P-PSD95 and P-Tau (direct JNK-targets) increased levels in tg vs control mice. These data indicate that JNK stress pathway is involved in neuronal degenerative mechanisms of this mouse model. In addition, P-JNK level is higher in females compared to male tg mice, underlying a sexual dimorphism in the JNK pathway activation. The behavioral studies highlight that tg females present major cognitive and locomotor defects, strongly correlated with a more severe synaptic injury, in comparison to tg male. Notably, at the dendritic spine level, JNK is powerfully activated and its level reveals a sexual dimorphism that is coherent with behavioral defects and spine pathology. The P301L’s synaptic pathology is characterized by a strong increase of P-PSD95/PSD95 and P-JNK/JNK ratios and by an augmented level of cleaved-Caspase-3 and a decrease of Drebrin level in the post-synaptic elements. These results suggest that JNK plays a key role in synaptopathy of P301L mice. Importantly, until now, there are any efficient treatments against synaptic pathology and JNK could represent an interesting target to tackle P-Tau-induced synaptic pathology. It will be important to test specific JNK inhibitors to verify their potential neuroprotective effect.