Crosstalk of MAP3K1 and EGFR signaling mediates gene-environment interactions that block developmental tissue closure.

Aberrant regulation of signal transduction pathways can adversely derail biological processes for tissue development. One such process is the embryonic eyelid closure that is dependent on the mitogen-activated protein kinase kinase kinase 1 (MAP3K1). Map3k1 KO in mice results in defective eyelid closure and an autosomal recessive eye-open at birth phenotype. We have shown that in utero exposure to dioxin, a persistent environmental toxicant, induces the same eye defect in Map3k1+/- heterozygous but not WT pups. Here, we explore the mechanisms of the Map3k1 (gene) and dioxin (environment) interactions (GxE) underlying defective eyelid closure. We show that, acting through the aryl hydrocarbon receptor, dioxin activates epidermal growth factor receptor signaling, which in turn depresses MAP3K1-dependent Jun N-terminal kinase (JNK) activity. The dioxin-mediated JNK repression is moderate but is exacerbated by Map3k1 heterozygosity. Therefore, dioxin exposed Map3k1+/- embryonic eyelids have a marked reduction of JNK activity, accelerated differentiation and impeded polarization in the epithelial cells. Knocking out Ahr or Egfr in eyelid epithelium attenuates the open-eye defects in dioxin-treated Map3k1+/- pups, whereas knockout of Jnk1 and S1pr that encodes the sphigosin-1-phosphate (S1P) receptors upstream of the MAP3K1-JNK pathway potentiates the dioxin toxicity. Our novel findings show that the crosstalk of aryl hydrocarbon receptor, epidermal growth factor receptor, and S1P-MAP3K1-JNK pathways determines the outcome of dioxin exposure. Thus, gene mutations targeting these pathways are potential risk factors for the toxicity of environmental chemicals.

Regulation of Notch signaling by non-muscle myosin II Zipper in Drosophila.

The Notch pathway is an evolutionarily conserved signaling system that is intricately regulated at multiple levels and it influences different aspects of development. In an effort to identify novel components involved in Notch signaling and its regulation, we carried out protein interaction screens which identified non-muscle myosin II Zipper (Zip) as an interacting partner of Notch. Physical interaction between Notch and Zip was further validated by co-immunoprecipitation studies. Immunocytochemical analyses revealed that Notch and Zip co-localize within same cytoplasmic compartment. Different alleles of zip also showed strong genetic interactions with Notch pathway components. Downregulation of Zip resulted in wing phenotypes that were reminiscent of Notch loss-of-function phenotypes and a perturbed expression of Notch downstream targets, Cut and Deadpan. Further, synergistic interaction between Notch and Zip resulted in highly ectopic expression of these Notch targets. Activated Notch-induced tumorous phenotype of larval tissues was enhanced by over-expression of Zip. Notch-Zip synergy resulted in the activation of JNK pathway that consequently lead to MMP activation and proliferation. Taken together, our results suggest that Zip may play an important role in regulation of Notch signaling.

Plasmodium parasitophorous vacuole membrane protein Pfs16 promotes malaria transmission by silencing mosquito immunity.

With rising cases for the first time in years, malaria remains a significant public health burden. The sexual stage of the malaria parasite infects mosquitoes to transmit malaria from host to host. Hence, an infected mosquito plays an essential role in malaria transmission. Plasmodium falciparum is the most dominant and dangerous malaria pathogen. Previous studies identified a sexual stage-specific protein 16 (Pfs16) localized to the parasitophorous vacuole membrane. Here, we elucidate the function of Pfs16 during malaria transmission. Our structural analysis identified Pfs16 as an alpha-helical integral membrane protein with one transmembrane domain connecting to two regions across parasitophorous vacuole membrane. ELISA assays showed that insect cell-expressed recombinant Pfs16 (rPfs16) interacted with Anopheles gambiae midguts, and microscopy found that rPfs16 was bound to midgut epithelial cells. Transmission-blocking assays demonstrated that polyclonal antibodies against Pfs16 significantly reduced the number of oocysts in mosquito midguts. However, on the contrary, feeding rPfs16 increased the number of oocysts. Further analysis revealed that Pfs16 reduced the activity of mosquito midgut caspase 3/7, a key enzyme in the mosquito Jun-N-terminal kinase immune pathway. We conclude that Pfs16 facilitates parasites to invade mosquito midguts by actively silencing the mosquito's innate immunity through its interaction with the midgut epithelial cells. Therefore, Pfs16 is a potential target to control malaria transmission.

A novel surface marker CD49d promotes TNF expression in oyster agranulocytes by mediating the MAPK pathway.

CD49d, encoded by the gene Integrin α4, is a significant member of cell adhesion receptors, which is widely expressed in various immune cells to trigger immune responses against invading pathogens. In the present study, the expression of CgCD49d and its regulatory role in TNF expression were investigated in the Pacific oyster Crassostrea gigas. There were five Int-alpha domains, an Integrin_alpha2 region and a unique FG-GAP repeat region inserted identified in CgCD49d. CgCD49d transcript was specifically expressed in haemocytes, and its mRNA expression level in haemocytes increased after LPS and Vibrio splendidus stimulation. After CgCD49d was blocked by using its antibody, the phosphorylation level of CgJNK in the MAPK signaling pathway and CgTNF transcripts decreased significantly post V. splendidus stimulation. After phosphorylation level of CgJNK was inhibited by using its inhibitor, the nuclear translocation of CgRel was restrained and CgTNF transcripts also decreased significantly post V. splendidus stimulation. Furthermore, CgCD49d was found to be mainly expressed in the agranulocyte subpopulation, and Alexa Fluor 488-conjugated CgCD49d antibody labeled agranulocytes with a circle of green fluorescence signals on CgCD49d+ agranulocyte surface under Confocal microscopy, which accounted for 24.9 ± 4.53% of total haemocytes. Collectively, these results suggested that CgCD49d promoted TNF expression in oyster haemocytes against bacterial invasion by mediating MAPK pathway, and it could be used as a surface marker to type and sort a subset of agranulocyte subpopulation among haemocytes.

Dexamethasone activates c-Jun NH2-terminal kinase (JNK) which interacts with GR and protects it from ubiquitin-mediated degradation in NSCLC cells.

Dexamethasone-mediated pharmacological activation of the glucocorticoid receptor (GR) is widely used in the treatment regimen of hematological malignancies and solid cancers. However, DEX sensitivity towards patients primarily depends on the endogenous protein levels of GR. We observed that DEX treatment leads to an increase in GR protein levels despite inhibition of neo-protein synthesis in non-small cell lung cancer (NSCLC) cells. Mechanistically, DEX-stimulation concomitantly increased the JNK phosphorylation and GR protein levels, however the JNK stimulation preceds GR upregulation. Moreover, we also observed that DEX-mediated phosphorylation is partially mediated by upregulation in MEKK1 phosphorylation. Further, GR protein levels were significantly decreased in JNK inhibitor (JNKi, SP600125) treated cells whereas MG132 treatment restored GR levels indicating that DEX induced JNK activity regulated the GR protein levels through proteasomal-degradation pathway. Next, we showed that DEX led to JNK activation which physically interacts with GR and protects it from ubiquitination-mediated degradation. Furthermore, at basal level GR interacts with JNK in cytoplasm whereas upon DEX stimulation GR and pJNK both localized to nucleus and interact with each other. Next, we show that JNK-mediated GR stabilization affects its nuclear transcriptional functional activity in NSCLC cells. In line with these in vitro data, patient dataset analysis also shows that increased levels of both JNK and GR contributes towards better prognosis of NSCLC patients. Taken together, our data shows that DEX treatment may lead to positive feedback regulation of GR by activating JNK and thus highlights importance of GR-JNK crosstalk in NSCLC.

p20BAP31 induces cell apoptosis via both AIF caspase-independent and the ROS/JNK mitochondrial pathway in colorectal cancer.

BACKGROUND: During cell apoptosis, the C-terminus of BAP31 is cleaved by caspase-8 and generates p20BAP31, which has been shown to induce an apoptotic pathway between the endoplasmic reticulum (ER) and mitochondria. However, the underlying mechanisms of p20BAP31 in cell apoptosis remains unclear. METHODS: We compared the effects of p20BAP31 on cell apoptosis in six cell lines and selected the most sensitive cells. Functional experiments were conducted, including Cell Counting Kit 8 (CCK-8), reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) assay. Then, cell cycle and apoptosis were investigated by flow cytometry and verified by immunoblotting. Next, NOX inhibitors (ML171 and apocynin), ROS scavenger (NAC), JNK inhibitor (SP600125), and caspase inhibitor (Z-VAD-FMK) were used to further investigate the underlying mechanisms of p20BAP31 on cell apoptosis. Finally, apoptosis-inducing factor (AIF) translocation from the mitochondria to the nuclei was verified by immunoblotting and immunofluorescence assay. RESULTS: We found that overexpression of p20BAP31 indeed induced apoptosis and had a much greater sensitivity in HCT116 cells. Furthermore, the overexpression of p20BAP31 inhibited cell proliferation by causing S phase arrest. Further study revealed that p20BAP31 reduced MMP, with a significant increase in ROS levels, accompanied by the activation of the MAPK signaling pathway. Importantly, the mechanistic investigation indicated that p20BAP31 induces mitochondrial-dependent apoptosis by activating the ROS/JNK signaling pathway and induces caspase-independent apoptosis by promoting the nuclear translocation of AIF. CONCLUSIONS: p20BAP31 induced cell apoptosis via both the ROS/JNK mitochondrial pathway and AIF caspase-independent pathway. Compared with antitumor drugs that are susceptible to drug resistance, p20BAP31 has unique advantages for tumor therapy.

Gambogenic acid induces apoptosis and autophagy through ROS-mediated endoplasmic reticulum stress via JNK pathway in prostate cancer cells.

Prostate cancer (PCa) is the most common malignant tumor in males, which frequently develops into castration-resistant prostate cancer (CRPC) with limited therapies. Gambogenic acid (GNA), a flavonoids compound isolated from Gamboge, exhibits anti-tumor capacity in various cancers. Our results showed that GNA revealed not only antiproliferative and pro-apoptotic activities but also the induction of autophagy in PCa cells. In addition, autophagy inhibitor chloroquine enhanced the pro-apoptosis effect of GNA. Moreover, the activation of JNK pathway and the induction of apoptosis and autophagy triggered by GNA were attenuated by JNK inhibitor SP600125. We also found that GNA significantly promoted reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress. Meanwhile, suppressing ER stress with 4-phenylbutyric acid (4-PBA) markedly blocked the activation of JNK pathway induced by GNA. Further research indicated that ROS scavenger N-acetyl-L-cysteine (NAC) effectively abrogated ER stress and JNK pathway activation induced by GNA. Furthermore, NAC and 4-PBA significantly reversed GNA-triggered apoptosis and autophagy. Finally, GNA remarkably suppressed prostate tumor growth with low toxicity in vivo. In conclusion, the present study revealed that GNA induced apoptosis and autophagy through ROS-mediated ER stress via JNK signaling pathway in PCa cells. Thus, GNA might be a promising therapeutic drug against PCa.

Physiological and Psychological Stress of Microwave Radiation-Induced Cardiac Injury in Rats.

Electromagnetic waves are widely used in both military and civilian fields, which could cause long-term and high-power exposure to certain populations and may pose a health hazard. The aim of this study was to simulate the long-term and high-power working environment of workers using special electromagnetic radiation occupations to clarify the radiation-induced stress response and cardiac damage and thus gain insights into the mechanisms of injuries caused by electromagnetic radiation. In this study, the combination of microwave and stress was an innovative point, aiming to broaden the research direction with regard to the effect and mechanism of cardiac injury caused by radiation. The myocardial structure was observed by optical and transmission electron microscope, mitochondrial function was detected by flow cytometry, oxidative-stress markers were detected by microplate reader, serum stress hormone was detected by radioimmunoassay, and heart rate variability (HRV) was analyzed by multichannel-physiological recorder. The rats were weighed and subjected to an open field experiment. Western blot (WB) and immunofluorescence (IF) were used to detect the expressions and distributions of JNK (c-Jun N-terminal kinase), p-JNK (phosphorylated c-Jun N-terminal kinase), HSF1 (heat shock factor), and NFATc4 (nuclear factor of activated T-cell 4). This study found that radiation could lead to the disorganization, fragmentation, and dissolution of myocardial fibers, severe mitochondrial cavitation, mitochondrial dysfunction, oxidative-stress injury in myocardium, increase to stress hormone in serum, significant changes in HRV, and a slow gain in weight. The open field experiment indicated that the rats experienced anxiety and depression and had decreased exercise capacity after radiation. The expressions of JNK, p-JNK, HSF1, and NFATc4 in myocardial tissue were all increased. The above results suggested that 30 mW/cm2 of S-band microwave radiation for 35 min could cause both physiological and psychological stress damage in rats; the damage was related to the activation of the JNK pathway, which provided new ideas for research on protection from radiation.

Spinocerebellar Ataxia in a Hungarian Female Patient with a Novel Variant of Unknown Significance in the CCDC88C Gene.

Spinocerebellar ataxia (SCA) 40 is an extremely rare subtype of the phenotypically and genetically diverse autosomal dominant ataxias caused by mutations of the CCDC88C gene. Most reported cases of SCA40 are characterized by late-onset cerebellar ataxia and variable extrapyramidal features; however, there is a report of a patient with early-onset spastic paraparesis as well. Here, we describe a novel missense CCDC88C mutation (p.R203W) in the hook domain of the DAPLE protein encoded by the CCDC88C gene that was identified in a female patient who developed late-onset ataxia, dysmetria and intention tremor. To explore the molecular consequences of the newly identified and previously described CCDC88C mutations, we carried out in vitro functional tests. The CCDC88C alleles were expressed in HEK293 cells, and the impact of the mutant DAPLE protein variants on JNK pathway activation and apoptosis was assessed. Our results revealed only a small-scale activation of the JNK pathway by mutant DAPLE proteins; however, increased JNK1 phosphorylation could not be detected. Additionally, none of the examined mutations triggered proapoptotic effect. In conclusion, we identified a novel mutation of the CCDC88C gene from a patient with spinocerebellar ataxia. Our results are not in accord with previous observations and do not support the primary role of the CCDC88C mutations in induction of JNK pathway activation in ataxia. Therefore, we propose that CCDC88C mutations may exert their effects through different and possibly in much broader, yet unexplored, biological processes.

Cell competition: A historical perspective.

Cell competition is a homeostatic process designed to remove from animal tissues viable cells that are unfit, abnormal or malignant and that may compromise the general fitness or the viability of the organism. Originally discovered in Drosophila in the mid-seventies of last century, there is strong evidence that it also occurs in other metazoans, where cell competition appears to play a similar surveillance role. In this review I summarize the field of cell competition, with special emphasis in the history of the phenomenon within the general frame of Developmental Biology in the second half of the XX century, pointing out the key observations and the evolution of ideas that have led to the current understanding.

MIG/CXCL9 exacerbates the progression of metabolic-associated fatty liver disease by disrupting Treg/Th17 balance.

CD4+CD25+ regulatory T (Treg) cells and Th17 cells play important roles in the progression of metabolic-associated fatty liver disease (MAFLD). However, the contribution of monokine induced by interferon-gamma (MIG)/CXCL9 to the Treg/Th17 imbalance in MAFLD is only partially understood. In the present study, we detected increased levels of MIG/CXCL9 and a Treg/Th17 imbalance in the setting of metabolic-associated steatohepatitis (MASH). Recombinant adeno-associated virus-mediated gene transfer and silencing of MIG/CXCL9 expression in mice alleviated MASH and increased the Treg/Th17 ratio. Furthermore, the percentage of Th17 cells, but not Treg cells, differentiated from splenic CD4+ T cells was significantly increased by administration of MIG/CXCL9. MIG/CXCL9 also promoted Th17 cell proliferation, and its effects were dose dependent. Levels of phosphorylated c-Jun N-terminal kinase (JNK) decreased dramatically when MIG/CXCL9 was inhibited in a murine MASH model. In cultured Treg cells, phosphorylated JNK levels decreased dose-dependently in response to MIG/CXCL9 inhibition, but increased in cultured Th17 cells. This effect was blocked in the presence of a JNK inhibitor. These findings underline the fundamental importance of MIG/CXCL9 in maintaining the Treg/Th17 balance in MAFLD and provide the foundations for a novel approach to preventing and treating MAFLD.

Delavatine A Attenuates OGD/R-Caused PC12 Cell Injury and Apoptosis through Suppressing the MKK7/JNK Signaling Pathway.

Delavatine A (DA) is an unusual isoquinoline alkaloid with a novel skeleton isolated from Chinese folk medicine Incarvillea delavayi. Studies conducted in our lab have demonstrated that DA has potential anti-inflammatory activity in lipopolysaccharide (LPS)-treated BV-2 cells. DA, however, has not been studied for its protective effect on neuronal cells yet. Thus, to explore whether DA can protect neurons, oxygen and glucose deprivation/reperfusion (OGD/R)-injured PC12 cell and middle cerebral artery occlusion/reperfusion (MCAO/R) rat model were used to assess the protective efficacy of DA against OGD/R damaged PC12 cells and MCAO/R injured rats. Our results demonstrated that DA pretreatment (0.31-2.5 µM) dose-dependently increased cell survival and mitochondrial membrane potential (MMP), whereas it lowered the leakage of lactate dehydrogenase (LDH), intracellular cumulation of Ca2+, and overproduction of reactive oxygen species (ROS), and inhibited the apoptosis rate in OGD/R-injured PC12 cells. Western blot demonstrated that DA pretreatment lowered the expression of apoptotic proteins and repressed the activation of the mitogen-activated protein kinase kinase 7 (MKK7)/c-Jun N-terminal kinase (JNK) pathway. It was also found that the neuroprotective efficacy of DA was significantly reversed by co-treatment with the JNK agonist anisomycin, suggesting that DA reduced PC12 cell injury and apoptosis by suppressing the MKK7/JNK pathway. Furthermore, DA oral administration greatly alleviated the neurological dysfunction and reduced the infarct volume of MCAO/R rats. Taken together, DA could ameliorate OGD/R-caused PC12 cell injury and improve brain ischemia/reperfusion (I/R) damage in MCAO/R rats, and its neuroprotection might be attributed to suppressing the MKK7/JNK signaling pathway.

Circulating JNK pathway-associated phosphatase: A novel biomarker correlates with Th17 cells, acute exacerbation risk, and severity in chronic obstructive pulmonary disease patients.

BACKGROUND: JNK pathway-associated phosphatase (JKAP) involves in the regulation of inflammation, immunity, and lung injury. The current study aimed to investigate correlation of JKAP with Th1, Th17 cells, acute exacerbation risk, and disease severity in chronic obstructive pulmonary disease (COPD) patients. METHODS: Totally, 45 stable COPD (SCOPD) patients, 45 acute exacerbation COPD (AECOPD) patients, and 45 controls were enrolled. Serum was collected for JKAP, interferon-gamma (IFN-γ) (Th1 cytokine), and interleukin 17 (IL-17) (Th17 cytokine) detection. Besides, peripheral blood mononuclear cell from COPD patients was collected for evaluating Th1 and Th17 cells. RESULTS: JKAP was highest in controls followed by SCOPD patients and lowest in AECOPD patients (median: 105.673 vs. 75.374 vs. 41.807 pg/ml, p < 0.001). Meanwhile, receiver operating characteristic (ROC) curves revealed that JKAP differentiated the AECOPD patients from the controls (area under curve (AUC): 0.910 (95% confidence interval (CI): 0.849-0.970)) and AECOPD patients from SCOPD patients (AUC: 0.726 (95% CI: 0.622-0.830)). Moreover, JKAP positively correlated with FEV1 (%predicted) in AECOPD patients (r = 0.347 p = 0.019). Additionally, JKAP was negatively correlated with the GOLD stage in AECOPD patients (r = -0.344, p = 0.021) and SCOPD patients (r = -0.357, p = 0.016). Whereas, JKAP was not associated with other clinical features (all p > 0.05). Besides, JKAP was negatively linked with Th17 cells (r = -0.378, p = 0.010), IFN-γ (r = -0.358, p = 0.016), IL-17 (r = -0.414, p = 0.005) in AECOPD patients and Th17 cells (r = -0.342, p = 0.022), IL-17 (r = -0.299, p = 0.046) in SCOPD patients. CONCLUSION: Downregulated JKAP correlates with Th17 cells, higher acute exacerbation risk, and severity in COPD patients, indicating its underlying potency as a biomarker for COPD.

MicroRNA Let-7a, -7e and -133a Attenuate Hypoxia-Induced Atrial Fibrosis via Targeting Collagen Expression and the JNK Pathway in HL1 Cardiomyocytes.

Fibrosis is a hallmark of atrial structural remodeling. The main aim of this study was to investigate the role of micro-ribonucleic acids (miRNAs) in the modulation of fibrotic molecular mechanisms in response to hypoxic conditions, which may mediate atrial fibrosis. Under a condition of hypoxia induced by a hypoxia chamber, miRNA arrays were used to identify the specific miRNAs associated with the modulation of fibrotic genes. Luciferase assay, real-time polymerase chain reaction, immunofluorescence and Western blotting were used to investigate the effects of miRNAs on the expressions of the fibrotic markers collagen I and III (COL1A, COL3A) and phosphorylation levels of the stress kinase c-Jun N-terminal kinase (JNK) pathway in a cultured HL-1 atrial cardiomyocytes cell line. COL1A and COL3A were found to be the direct regulatory targets of miR-let-7a, miR-let-7e and miR-133a in hypoxic atrial cardiac cells in vitro. The expressions of COL1A and COL3A were influenced by treatment with miRNA mimic and antagomir while hypoxia-induced collagen expression was inhibited by the delivery of miR-133a, miR-let-7a or miR-let-7e. The JNK pathway was critical in the pathogenesis of atrial fibrosis. The JNK inhibitor SP600125 increased miRNA expressions and repressed the fibrotic markers COL1A and COL3A. In conclusion, MiRNA let-7a, miR-let-7e and miR-133a play important roles in hypoxia-related atrial fibrosis by inhibiting collagen expression and post-transcriptional repression by the JNK pathway. These novel findings may lead to the development of new therapeutic strategies.

The Possible Connection of Two Dual Function Processes: The Relationship of Ferroptosis and the JNK Pathway.

Ferroptosis represents a typical process that has dual functions in cell fate decisions since the reduction and/or inhibition of ferroptosis is desirable for the therapies of diseases such as neurological disorders, localized ischemia-reperfusion, kidney injury, and hematological diseases, while the enhanced ferroptosis of cancer cells may benefit patients with cancer. The JNK pathway also has a real dual function in the fate of cells. Multiple factors suggest a potential link between the ferroptotic and JNK pathways; (i) both processes are ROS mediated; (ii) both can be inhibited by lipid peroxide scavengers; (iii) RAS mutations may play a role in the initiation of both pathways. We aimed to investigate the possible link between ferroptosis and the JNK pathway. Interestingly, JNK inhibitor co-treatment could enhance the cancer cytotoxic effect of the ferroptosis inducers in NRAS and KRAS mutation-harboring cells (HT-1080 and MIA PaCa-2). Since cancer's cytotoxic effect from the JNK inhibitors could only be suspended by the ferroptosis inhibitors, and that sole JNK-inhibitor treatment did not affect cell viability, it seems that the JNK inhibitors "just" amplify the effect of the ferroptosis inducers. This cancer cell death amplifying effect of the JNK inhibitors could not be observed in other oxidative stress-driven cell deaths. Hence, it seems it is specific to ferroptosis. Finally, our results suggest that GSH content/depletion could be an important candidate for switching the anti-cancer effect of JNK inhibitors.

Caspase-3-mediated GSDME induced Pyroptosis in breast cancer cells through the ROS/JNK signalling pathway.

Pyroptosis is a new form of programmed cell death generated by some inflammasomes, piloting the cleavage of gasdermin (GSDM) and stimulation of dormant cytokines like IL-18 and IL-1ß; these reactions are narrowly linked to certain diseases like diabetic nephropathy and atherosclerosis. Doxorubicin, a typical anthracycline, and famous anticancer drug has emerged as a prominent medication in several cancer chemotherapies, although its application is accompanied with expending of dose-dependent, increasing, irreversible and continuing cardiotoxic side effects. However, the exact path that links the induced pyroptosis to the mechanism by which Doxorubicin (DOX) acts against breast cancer cells is still puzzling. The present study seeks to elucidate the potential link between DOX-induced cell death and pyroptosis in two human breast cancer cell lines (MDA-MB-231 and T47D). We proved that treatment with DOX reduced the cell viability in a dose-dependent way and induced pyroptosis morphology in MDA-MB-231 and T47D cells. Also, protein expression analyses revealed GSDME as a key regulator in DOX-induced pyroptosis and highlighted the related role of Caspase-3 activation. Furthermore, DOX treatments induced intracellular accumulation of ROS, stimulated the phosphorylation of JNK, and Caspase-3 activation, subsequently. In conclusion, the study suggests that GSDME triggered DOX-induced pyroptosis in the caspase-3 dependent reactions through the ROS/JNK signalling pathway. Additionally, it showed that the DOX-induced cardiotoxicity and pyroptosis in breast cancer cells can be minimized by reducing the protein level of GSDME; thus, these outcomes provide a new research target and implications for the anticancer investigations and therapeutic applications.

Inhibition of ER stress-activated JNK pathway attenuates TNF-α-induced inflammatory response in bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (BMMSCs) are characterized by their pluripotent differentiation and self-renewal capability and have been widely applied in regenerative medicine, gene therapy, and tissue repair. However, inflammatory response after BMMSCs transplantation was found to impair the osteogenic differentiation of BMMSCs. Thus, understanding the mechanisms underlying inflammation response will benefit the clinical use of BMMSCs. In this study, using a cell model of TNF-α-induced inflammatory response, we found that TNF-α treatment greatly elevated intracellular oxidative stress and induced endoplasmic reticulum (ER) stress by elevating the expression levels of ER sensors, such as PERK, ATF6 and IRE1A. Oxidative stress and ER stress formed a feedback loop to mediate TNF-α-induced inflammation response in BMMSCs. Moreover, c-Jun N-terminal kinase (JNK) signal pathway that coupled to the ER stress was significantly activated by increasing its phosphorylation upon TNF-α treatment. Importantly, pharmacological inhibition of ER stress effectively eliminated the phosphorylation of JNK and attenuated the TNF-α-induced inflammation response. In conclusion, our results indicated that TNF-α induced oxidative and ER stress, thereby leading to JNK activation, and generating inflammation response in BMMSCs. This pathway underlying TNF-α-induced inflammation response may provide new strategies to improve BMMSCs osteogenesis and other inflammation-associated bone diseases.

Protective Effect of Hydrogen Gas on Mouse Hind Limb Ischemia-Reperfusion Injury.

BACKGROUND: The aim of this study was to investigate the mechanism of hydrogen gas on hind limb IR injury. METHODS: Male C57BL/6 mice were randomly divided into three groups: sham group (Sham), ischemia-reperfusion group (IR), IR plus H2 inhalation group (IR + H2). IR was induced by interrupting hind limb blood flow for 3h, followed by 4h of reperfusion, and H2 was administered by inhalation throughout the reperfusion process. Our data show that H2 inhalation could significantly decrease the infarct-affected tissue volume (P < 0.05), attenuate the degree of morphological injury (P < 0.05), and suppress the level of oxidative stress damage (P < 0.05), compared with the IR group. In exploring the underlying mechanisms, we found that hydrogen could markedly mitigate the degree of IR-induced ER stress and apoptosis (P < 0.05). Additionally, hydrogen could markedly inhibit the IR injury by modulating the phosphorylated c-Jun N-terminal kinase (JNK) signaling pathway (P < 0.05). CONCLUSIONS: Taken together, these results revealed the protective effect of hydrogen gas on hind limb ischemia reperfusion injury on mice by attenuating oxidative stress, impairing ER stress and apoptosis, and its ability to modulate JNK signaling pathway.

The regulatory role of SFRP5/WNT5A axis in allergic rhinitis through inhibiting JNK pathway activation and lowering mucin generation in human nasal epithelial cells.

Allergic rhinitis (AR) is tightly associated with type 2 inflammation. SFRP5 combined with WNT5A mainly inhibits chronic inflammatory response, atherosclerosis, and other metabolic disorders. However, the effect of SFRP5/WNT5A axis on recombinant human interleukin-13 (rhIL-13)-induced inflammation has not been studied. In this study, we aimed to investigate whether secreted frizzled-related protein 5 (SFRP5) could modulate the production of cytokines relevant to eosinophil infiltration and mucin secretion through blocking the activation of Wnt family 5A (WNT5A) signaling pathway. A mouse model of AR demonstrated low expression of SFRP5 and high expression of WNT5A, and indicated that the number of eosinophil and goblet cells was increased, concomitant with elevated IL-13, colony stimulating factor 2 (CSF2), chemokine ligand 11 (CCL11), Mucin 4, and Mucin 5AC levels. Furthermore, lentivirus-SFRP5 overexpression up-regulated the expression of SFRP5 but down-regulated WNT5A level, and inhibited the activation of JNK pathway via decreasing p-JNK1/2 (Thr183/Tyr185) and p-c-Jun (Ser73) protein expressions in rhIL-13-treated human nasal epithelial cells (HNEpCs). Noticeably, SFRP5 overexpression markedly reduced rhIL-13-induced inflammatory protein and mucin generation through lowered CSF2, CCL11, Mucin 4, as well as Mucin 5AC levels. Taken together, these findings confirmed the regulatory role of SFRP5/WNT5A axis in rhIL-13-mediated inflammatory response in HNEpCs.

Nicotinamide phosphoribosyltransferase inhibitor is a novel therapeutic candidate in LPS-induced neutrophil extracellular traps.

Neutrophil extracellular traps (NETs) are beneficial antibacterial defense structures. However, excessive NETs have also been linked to tissue damage and organ dysfunction. LPS and Gram-negative bacteria induce the formation of reactive oxygen species (ROS)-dependent NETs via the JNK pathway. It was found previously that knockdown of nicotinamide phosphoribosyltransferase (NAMPT) upregulates surfactant protein B (SFTPB or SP-B) and attenuates LPS-induced acute lung injury (ALI) via inhibiting JNK activation. This study investigated the effect of FK866, an intracellular NAMPT inhibitor, on the formation of LPS-induced NETs in mouse bronchoalveolar lavage (BAL) neutrophils and in differentiated HL-60 cells. The results show that inhibition of NAMPT by FK866 suppresses NETs formation in BAL neutrophils from the mice exposed to LPS. FK866 also suppresses NETs formation in the differentiated HL-60 cells stimulated with LPS. Additional data indicate that these effects are mediated by suppressing ROS production at least partly via inhibiting JNK activation and depleting NAD(P)H. The utility of inhibition of intracellular NAMPT may be a potential therapy for LPS-induced NETs-related diseases.