All-trans Retinoic Acid Diminishes Collagen Production in a Hepatic Stellate Cell Line via Suppression of Active Protein-1 and c-Jun N-terminal Kinase Signal

Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoid loss and its potential roles in HSCs activation and liver fibrosis are not understood.The influence of retinoids on HSCs and hepatic fibrosis remains controversial.The purpose of this study was to evaluate the effects of all-trans retinoid acid (ATRA) on cell proliferation,mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),fibrolytic genes (MMP-3,MMP-13) and the upstream element (JNK and AP-1) in the rat hepatic stellate cell line (CFSC-2G).Cell proliferation was evaluated by measuring BrdU incorporation.The mRNA expression levels of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and fibrolytic genes (MMP-3,MMP-13) were quantitatively detected by using real-time PCR.The mRNA expression of JNK and AP-1 was quantified by RT-PCR.The results showed that ATRA inhibited HSCs proliferation and diminished the mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)] and profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly stimulated the mRNA expression of MMP-3 and MMP-13 in HSCs by suppressing the mRNA expression of JNK and AP-1.These findings suggested that ATRA could inhibit proliferation and collagen production of HSCs via the suppression of active protein-1 and c-Jun N-terminal kinase signal,then decrease the mRNAs expression of profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly induce the mRNA expression of MMP-3 and MMP-13.

Experimental study on the apoptosis of cervical cancer Hela cells induced by juglone through c-Jun N-terminal kinase/c-Jun pathway

Objective: To study the regulatory effect and molecular mechanism of juglone on apoptosis of cervical cancer Hela cells. Methods: Cervical cancer Hela cells were cultured and treated with different dosages of juglone (10, 20, and 40 pmol/L, respectively) and c-Jun N-terminal kinase (JNK) inhibitor SP600125 (10, 20, and 40 mu mol/L. respectively). Then cellular proliferative activity and the expression of JNK/c-Jun pathway molecule and apoptotic molecule in the cells were detected. Results: After 6, 12. 18 and 24 h of treatment, the value for proliferative activity of cells treated with juglone was significantly lower than that of control group (p<0.05), and the anti-proliferative effect was more significant as the treatment period and juglone dosage increased (P<0.05). The protein expressions of Box, CytC, Fas, FasL, Caspase-3, and p-c-Jun in cells treated with juglone were significantly higher than those of control group (P<0.05), and the protein expressions of Bax, CytC, Fas. FasL, Caspase-3, p-JNK and p-c-Jun increased more remarkably as the juglone dosage increased (P<0.05). In cells treated with 40 pmol/L juglone and SP600125, the protein expressions of Bax, CytC, Fas. Fast.. and Caspase-3 were significantly lower than those of cells treated with 40 pmol/L juglone (J<0.05), and the protein expressions of Bax, CytC, Fas, FasL and Caspase-3 reduced more remarkably as the SP600125 dosage increased (P<0.05). Conclusion: Juglone can increase the expression of apoptotic molecules in mitochondrial pathway and death receptor pathway by activating JNK/c-Jun pathway, thus inducing apoptosis of cervical cancer cells.

S-adenosyl-methionine decreases ethanol-induced apoptosis in primary hepatocyte cultures by a c-Jun N-terminal kinase activity-independent mechanism

AIM： To determine the role of c-Jun N-terminal kinase （JNK） activity in ethanol-induced apoptosis and the modulation of this signaling cascade by S-Adenosylmethionine （AdoMet）. METHODS： Primary hepatocyte cultures were pretreated with 100 IJmol/L SP600125, a selective JNK inhibitor, 1 mL/L DMSO or 4 mmol/L AdoMet and then exposed to 100 mmo/L ethanol. Hepatocyte apoptosis was determined by the TUNEL and DNA ladder assays. JNK activity and its inhibition by SP600125 and AdoMet were determined by Western blot analysis of c-jun phosphorylation and Bid fragmentation. SP600125 and AdoMet effects on the apoptotic signaling pathway were determined by Western blot analysis of cytochrome c release and pro-caspase 3 fragmentation. The AdoMet effect on glutathione levels was measured by EIIman＇s method and reactive oxygen species （ROS） generation by cell cytometry. RESULTS： The exposure of hepatocytes to ethanol induced JNK activation, c-jun phosphorylation, Bid fragmentation, cytochrome c release and pro-caspase 3 cleavage; these effects were diminished by SP600125, and caused a significant decrease in ethanol-induced apoptosis （P〈 0.05）. AdoMet exerted an antioxidant effect maintaining glutathione levels and decreasing ROS generation, without a significant effect on JNK activity, and prevented cytochrome c release and pro-caspase 3 cleavage.CONCLUSION： The JNK signaling cascade is a key component of the proapoptotic signaling pathway induced by ethanol. JNK activation may be independent from ROS generation, since AdoMet which exerted antioxidant properties did not have a significant effect on JNK activity. JNK pathway modulator agents and AdoMet may be components of promising therapies for alcoholic liver disease （ALD） treatment.

c-Jun N-terminal kinase-mediated Rubicon expression enhances hepatocyte lipoapoptosis and promotes hepatocyte ballooning

AIM: To clarify the relationship between autophagy and lipotoxicity-induced apoptosis, which is termed "lipoapoptosis," in non-alcoholic steatohepatitis. METHODS: Male C57BL/6J mice were fed a high-fat diet(HFD) for 12 wk, after which the liver histology and expression of proteins such as p62 or LC3 were evaluated. Alpha mouse liver 12(AML12) cells treated with palmitate(PA) were used as an in vitro model. RESULTS: LC3-Ⅱ, p62, and Run domain Beclin-1 interacting and cysteine-rich containing(Rubicon) proteins increased in both the HFD mice and in AML12 cells in response to PA treatment. Rubicon expression was decreased upon c-Jun N-terminal kinase(JNK) inhibition at both the m RNA and the protein level in AML12 cells. Rubicon knockdown in AML12 cells with PA decreased the protein levels of both LC3-Ⅱ and p62. Rubicon expression peaked at 4 h of PA treatment in AML12, and then decreased. Treatment with caspase-9 inhibitor ameliorated the decrease in Rubicon protein expression at 10 h of PA and resulted in enlarged AML12 cells under PA treatment. The enlargement of AML12 cells by PA with caspase-9 inhibition was canceled by Rubicon knockdown.CONCLUSION: The JNK-Rubicon axis enhanced lipoapoptosis, and caspase-9 inhibition and Rubicon had effects that were cytologically similar to hepatocyte ballooning. As ballooned hepatocytes secrete fibrogenic signals and thus might promote fibrosis in the liver, the inhibition of hepatocyte ballooning might provide antifibrosis in the NASH liver.

c-Jun N-terminal kinase is required for thermotherapyinduced apoptosis in human gastric cancer cells

AIM:To investigate the role of c-Jun N-terminal kinase(JNK) in thermotherapy-induced apoptosis in human gastric cancer SGC-7901 cells.METHODS:Human gastric cancer SGC-7901 cells were cultured in vitro.Following thermotherapy at 43 ℃ for 0,0.5,1,2 or 3 h,the cells were cultured for a further 24 h with or without the JNK specific inhibitor,SP600125 for 2 h.Apoptosis was evaluated by immunohistochemistry [terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL)] and flow cytometry(Annexin vs propidium iodide).Cell proliferation was determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.The production of p-JNK,Bcl-2,Bax and caspase-3 proteins was evaluated by Western blotting.The expression of JNK at mRNA level was determined by reverse transcription polymerase chain reaction.RESULTS:The proliferation of gastric carcinoma SGC-7901 cells was significantly inhibited following thermotherapy,and was 32.7%,30.6%,43.8% and 52.9% at 0.5,1,2 and 3 h post-thermotherapy,respectively.Flow cytometry analysis revealed an increased population of SGC790l cells in G0/G1 phase,but a reduced population in S phase following thermotherapy for 1 or 2 h,compared to untreated cells(P < 0.05).The increased number of SGC-790l cells in G0/G1 phase was consistent with induced apoptosis(flow cytometry) following thermotherapy for 0.5,1,2 or 3 h,compared to the untreated group(46.5% ± 0.23%,39.9% ± 0.53%,56.6% ± 0.35% and 50.4% ± 0.29% vs 7.3% ± 0.10%,P < 0.01),respectively.This was supported by the TUNEL assay(48.2% ± 0.4%,40.1% ± 0.2%,61.2% ± 0.29% and 52.0% ± 0.42% vs 12.2% ± 0.22%,P < 0.01) respectively.More importantly,the expression of p-JNK protein and JNK mRNA levels were significantly higher at 0.5 h than at 0 h post-treatment(P < 0.01),and peaked at 2 h.A similar pattern was detected for Bax and caspase-3 proteins.Bcl-2 increased at 0.5 h,peaked at 1 h,and then decreased.Furthermore,the JNK specific inhibitor,SP600125,suppressed p-JNK,Bax and caspase-3 at the protein level in SGC790l cells following thermotherapy,compared to mock-inhibitor treatment,which was in line with the decreased rate of apoptosis.The expression of Bcl-2 was consistent with thermotherapy alone.CONCLUSION:Thermotherapy induced apoptosis in gastric cancer cells by promoting p-JNK at the mRNA and protein levels,and up-regulated the expression of Bax and caspase-3 proteins.Bcl-2 may play a protective role during thermotherapy.Activation of JNK via the Bax-caspase-3 pathway may be important in thermotherapy-induced apoptosis in gastric cancer cells.

Correlation between spina bifida manifesta in fetal rats and c-Jun N-terminal kinase signaling

Fetal rat models with neural tube defects were established by injection with retinoic acid at 10 days after conception. The immunofluorescence assay and western blot analysis showed that the number of caspase-3 positive cells in myeloid tissues for spina bifida manifesta was increased. There was also increased phosphorylation of c-Jun N-terminal kinase, a member of the mitogen activated protein kinase family. The c-Jun N-terminal kinase phosphorylation level was positively correlated with caspase-3 expression in myeloid tissues for spina bifida manifesta. Experimental findings indicate that abnormal apoptosis is involved in retinoic acid-induced dominant spina bifida formation in fetal rats, and may be associated with the c-Jun N-terminal kinase signal transduction pathway.

c-Jun N-terminal kinase 3 deficiency protects axotomized retinal ganglion cells via affecting mitochondria involved apoptosis pathway

AIM: To illustrate the isoform-specific role and mechanism of c-Jun N-terminal kinases(JNKs) in mouse optic nerve axotomy induced neurotrauma. METHODS: We firstly investigated the expression of JNK1, JNK2, and JNK3 in the retinal ganglion cells(RGCs) by double-immunofluorescent staining. Then we created optic nerve axotomy model in wild type as well as JNK1, JNK2, JNK3, isoform specific gene deficiency mice. With that, we checked the protein expression profile of JNKs and its active form, and quantified the survival RGCs number by immunofluorescence staining. We further explored the molecules underlying isoform specific protective effect by real-time polymerase chain reaction(PCR) and Western blotting assay. RESULTS: We found that all the three isoforms of JNKs were expressed in the RGCs. Deficiency of JNK3, but not JNK1 or JNK2, significantly alleviated optic nerve axotomyinduced RGCs apoptosis. We further established that expression of Noxa, a pro-apoptotic member of BH3 family, was significantly suppressed only in JNK3 gene deficiency mice. But tumor necrosis factor receptor 1(TNFR1) and Fas, two key modulators of death receptor mediated apoptosis pathway, did not display obvious change in the expression. CONCLUSION: It is suggested that mitochondria mediated apoptosis, but not death receptor mediated apoptosis got involved in the JNK3 gene deficiency induced RGCs protection. Our study provides a novel insight into the isoform-specific role of JNKs in neurotrauma and indicates some cues for its therapeutics.

Mitogen-activated protein kinase phosphatase 1 protects PC12 cells from amyloid beta-induced neurotoxicity

The mitogen-activated protein kinase（MAPK） signaling pathway plays an important role in the regulation of cell growth, proliferation, differentiation, transformation and death. Mitogen-activated protein kinase phosphatase 1（MKP1） has an inhibitory effect on the p38 MAPK and JNK pathways, but it is unknown whether it plays a role in Aβ-induced oxidative stress and neuronal inflammation. In this study, PC12 cells were infected with MKP1 sh RNA, MKP1 lentivirus or control lentivirus for 12 hours, and then treated with 0.1, 1, 10 or 100 μM amyloid beta 42（Aβ42）. The cell survival rate was measured using the cell counting kit-8 assay. MKP1, tumor necrosis factor-alpha（TNF-α） and interleukin-1β（IL-1β） m RNA expression levels were analyzed using quantitative real time-polymerase chain reaction. MKP1 and phospho-c-Jun N-terminal kinase（JNK） expression levels were assessed using western blot assay. Reactive oxygen species（ROS） levels were detected using 2′,7′-dichlorofluorescein diacetate. Mitochondrial membrane potential was measured using flow cytometry. Superoxide dismutase activity and malondialdehyde levels were evaluated using the colorimetric method. Lactate dehydrogenase activity was measured using a microplate reader. Caspase-3 expression levels were assessed by enzyme-linked immunosorbent assay. Apoptosis was evaluated using the terminal deoxynucleotidyl transferase d UTP nick end labeling method. MKP1 overexpression inhibited Aβ-induced JNK phosphorylation and the increase in ROS levels. It also suppressed the Aβ-induced increase in TNF-α and IL-1β levels as well as apoptosis in PC12 cells. In contrast, MKP1 knockdown by RNA interference aggravated Aβ-induced oxidative stress, inflammation and cell damage in PC12 cells. Furthermore, the JNK-specific inhibitor SP600125 abolished this effect of MKP1 knockdown on Aβ-induced neurotoxicity. Collectively, these results show that MKP1 mitigates Aβ-induced apoptosis, oxidative stress and neuroinflammation by inhibiting the JNK signaling pathway, thereby playing a neuroprotective role.

Ceramide from sphingomyelin hydrolysis differentially mediates mitogen-activated protein kinases (MAPKs) activation following cerebral ischemia in rat hippocampal CA1 subregion

Objective： To explore the role that ceramide plays in the activation of mitogen-activated protein kinases （MAPKs） during cerebral ischemia and reperfusion. Methods： Rats were subjected to ischemia by the fourvessel occlusion （4-VO） method. The sphingomyelinase inhibitor TPCK was administered to the CA1 subregion of the rat hippocampus before inducing ischemia. Western blot was used to examine the activity of extracellular- signal regulated kinase （ERK） and c-Jun N-terminal protein kinase （JNK） using antibodies against ERK, JNK and diphosphorylated ERK and JNK. Results： At lh reperfusion post-ischemia, JNK reached its peak activity while ERK was undergoing a sharp inactivation （P 〈 0.05）. The level of diphosphorylated JNK was significantly reduced but the sharp inactivation of ERK was visibly reversed （P 〈 0.05） by the sphingomyelinase inhibitor. Conclusion： The ceramide signaling pathway is up-regulated through sphingomyelin hydrolysis in brain ischemia, promoting JNK activation and suppressing ERK activation, culminating in the ischemic lesion.

Activation of c-Jun N-terminal kinase 1/2 regulated by nitric oxide is associated with neuronal survival in hippocampal neurons in a rat model of ischemia

Background C-Jun N-terminal kinase （JNK） signaling pathway plays a critical role in cerebral ischemia. Although the mechanistic basis for this activation of JNK1/2 is uncertain, oxidative stress may play a role. The purpose of this study was to investigate whether the activation of JNK1/2 is associated with the production of endogenous nitric oxide （NO）. Methods Ischemia and reperfusion （I/R） was induced by cerebral four-vessel occlusion. Sprague-Dawley （SD） rats were divided into 6 groups： sham group, I/R group, neuronal nitric oxide synthase （nNOS） inhibitor （7-nitroindazole, 7-NI） given group, inducible nitric oxide synthase （iNOS） inhibitor （2-amino-5,6-dihydro-methylthiazine, AMT） given group, sodium chloride control group, and 1% dimethyl sulfoxide （DMSO） control group. The levels of protein expression and phospho-JNK1/2 were detected by Western blotting and the survival hippocampus neurons in CA1 zone were observed by cresyl violet staining. Results The study illustrated two peaks of JNK1/2 activation occurred at 30 minutes and 3 days during reperfusion. 7-NI inhibited JNK1/2 activation during the early reperfusion, whereas AMT preferably attenuated JNK1/2 activation during the later reperfusion. Administration of 7-NI and AMT can decrease I/R-induced neuronal loss in hippocampal CA1 region. Conclusion JNK1/2 activation is associated with endogenous NO in response to ischemic insult.

Serine-threonine protein kinase activation may be an effective target for reducing neuronal apoptosis after spinal cord injury

The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, including extracellular signal-regulated kinase（ERK）, serine-threonine protein kinase（Akt） and c-Jun N-terminal kinase（JNK） signaling pathways. We established a rat model of acute spinal cord injury by inserting a catheter balloon in the left subclavian artery for 25 minutes. Rat models exhibited notable hindlimb dysfunction. Apoptotic cells were abundant in the anterior horn and central canal of the spinal cord. The number of apoptotic neurons was highest 48 hours post injury. The expression of phosphorylated Akt（pAkt） and phosphorylated ERK（p-ERK） increased immediately after reperfusion, peaked at 4 hours（p-Akt） or 2 hours（p-ERK）, decreased at 12 hours, and then increased at 24 hours. Phosphorylated JNK expression reduced after reperfusion, increased at 12 hours to near normal levels, and then showed a downward trend at 24 hours. Pearson linear correlation analysis also demonstrated that the number of apoptotic cells negatively correlated with p-Akt expression. These findings suggest that activation of Akt may be a key contributing factor in the delay of neuronal apoptosis after spinal cord ischemia, particularly at the stage of reperfusion, and thus may be a target for neuronal protection and reduction of neuronal apoptosis after spinal cord injury.

Stress-activated kinases as therapeutic targets in pancreatic cancer

Pancreatic cancer is a dismal disease with high incidence and poor survival rates.With the aim to improve overall survival of pancreatic cancer patients,new therapeutic approaches are urgently needed.Protein kinases are key regulatory players in basically all stages of development,maintaining physiologic functions but also being involved in pathogenic processes.c-Jun N-terminal kinases(JNK)and p38 kinases,representatives of the mitogen-activated protein kinases,as well as the casein kinase 1(CK1)family of protein kinases are important mediators of adequate response to cellular stress following inflammatory and metabolic stressors,DNA damage,and others.In their physiologic roles,they are responsible for the regulation of cell cycle progression,cell proliferation and differentiation,and apoptosis.Dysregulation of the underlying pathways consequently has been identified in various cancer types,including pancreatic cancer.Pharmacological targeting of those pathways has been the field of interest for several years.While success in earlier studies was limited due to lacking specificity and off-target effects,more recent improvements in small molecule inhibitor design against stress-activated protein kinases and their use in combination therapies have shown promising in vitro results.Consequently,targeting of JNK,p38,and CK1 protein kinase family members may actually be of particular interest in the field of precision medicine in patients with highly deregulated kinase pathways related to these kinases.However,further studies are warranted,especially involving in vivo investigation and clinical trials,in order to advance inhibition of stress-activated kinases to the field of translational medicine.

Effects of Different Therapeutic Methods and Typical Recipes of Chinese Medicine on Activation of c-Jun N-terminal Kinase in Kupffer Cells of Rats with Fatty Liver Disease

Objective： To observe the effects of different therapeutic methods and the recipes of Chinese medicine （CM） on the activation of c-Jun N-terminal kinase （JNK） in Kupffer cells of rats with fatty liver disease and to explore the mechanisms of these therapeutic methods. Methods： By using a random number table, 98 rats were randomly divided into 7 groups： control group, model group, and 5 treatment groups, including soothing Liver （Gan） recipe group, invigorating Spleen （Pi） recipe group, dispelling dampness recipe group, promoting blood recipe group, and complex recipe group. Rats in the control group were fed with normal food and distilled water by gastric perfusion, while rats in the model group were fed with high-fat food and distilled spirits by gastric perfusion. Rats in the 5 treatment groups were fed with high-fat food and corresponding recipes by gastric perfusion. Twelve weeks later, all rats were sacrificed and liver tissues were stained for pathohistological observation. Kupffer cells were isolated from livers of rats to evaluate JNK and phospho-JNK expressions by Western blotting. Results： The grade of hepatic steatosis was higher in the model group than the control group （P〈0.05）. Compared with the model group, the grade of fatty degeneration in soothing Liver recipe group and invigorating Spleen recipe group were significantly ameliorated （P〈0.05）. Expressions of JNK and phospho-JNK in Kupffer cells were significantly higher in the model group than those in the control group （P〈0.05, P〈0.01）. Compared with the model group, expressions of JNK in all treatment groups decreased, especially in invigorating Spleen recipe group and promoting blood recipe group （P〈0.05）. Compared with the model group, expressions of phospho-JNK in all treatment groups declined significantly （P〈0.01）, especially in soothing Live recipe group and invigorating Spleen recipe group. Conclusions： The high expressions of JNK and phospho-JNK in Kupffer cells might play an important role in the pathogenesis of fatty liver disease in rats. The recipes of CM, especially invigorating Spleen recipe and soothing Liver recipe, might protect liver against injury by reducing the total JNK protein content and inhibiting the activation of JNK protein in Kupffer cells of fatty liver model rats, which showed beneficial effects on fatty liver disease.

Inhibition of c-Jun N-terminal Kinase Signaling Pathway Alleviates Lipopolysaccharide-induced Acute Respiratory Distress Syndrome in Rats

Background： An acute respiratory distress syndrome （ARDS） is still one of the major challenges in critically ill patients. This study aimed to investigate the effect of inhibiting c-Jun N-terminal kinase （JNK） on ARDS in a lipopolysaccharide （LPS）-induced ARDS rat model. Methods： Thirty-six rats were randomized into three groups： control, LPS, and LPS ＋ JNK inhibitor Rats were sacrificed 8 h alter LPS treatment. The lung edema was observed by measuring the wet-to-dry weight （W/D） ratio of the lung. The severity of ptdmonary inflammation was observed by measuring myeloperoxidase （MPO） activity of lung tissue. Moreover, the neutrophils in bronchoalveolar lavage fluid （BALF） were cotinted to observe the airway inflammation. In addition, lung collagen accumulation was quantified by Sircol Collagen Assay. At the same time, the pulmonary histologic examination was perlbrmed, and lung injury score was achieved in all three groups. Results： MPO activity in lung tissue was found increased in rats treated with LPS comparing with that in control （I.26 ＋ 0.15 U in LPS vs. 0.77 ± 0.27 U in control, P 〈 0.05）. Inhibiting ,INK attenuated LPS-induced MPO activity upregulation （0.52 ± 0. 12 U in LPS ＋ JNK inhibitor vs. 1.26 ± 0.15 U in LPS, P 〈 0.05）. Neutrophils in BALF were also found to be increased with LPS treatment, and inhibiting ,INK attenuated LPS-induced neutrophils increase in BALF （255.0 ± 164.4 in LPS vs. 53 （44.5-103） in control vs. 127.0 ± 44.3 in LPS JNK inhibitor, P 〈 0.05）. At the same time, the lung injury score showed a reduction in LPS ＋ JNK inhibitor group comparing with that in LPS group （ 13.42 ± 4.82 vs. 7.00 ± 1.83, P 0.001 ）. However, the lung W/D ratio and the collagen in BALF did not show any difl＇erences between LPS and LPS ＋ JNK inhibitor group.Conclusions： Inhibiting JNK alleviated LPS-induced acute lung inflammation and had no effects on pulmonary edema and fibrosis..INK inhibitor might be a potential therapeutic medication in ARDS, in the context of reducing lung inflammatory.

Jianpi Gushen Huayu decoction ameliorated diabetic nephropathy through modulating metabolites in kidney,and inhibiting TLR4/NF-κB/NLRP3 and JNK/P38 pathways

BACKGROUND Jianpi Gushen Huayu Decoction(JPGS)has been used to clinically treat diabetic nephropathy(DN)for many years.However,the protective mechanism of JPGS in treating DN remains unclear.AIM To evaluate the therapeutic effects and the possible mechanism of JPGS on DN.METHODS We first evaluated the therapeutic potential of JPGS on a DN mouse model.We then investigated the effect of JPGS on the renal metabolite levels of DN mice using non-targeted metabolomics.Furthermore,we examined the effects of JPGS on c-Jun N-terminal kinase(JNK)/P38-mediated apoptosis and the inflammatory responses mediated by toll-like receptor 4(TLR4)/nuclear factor-kappa B(NF-κB)/NOD-like receptor family pyrin domain containing 3(NLRP3).RESULTS The ameliorative effects of JPGS on DN mice included the alleviation of renal injury and the control of inflammation and oxidative stress.Untargeted metabolomic analysis revealed that JPGS altered the metabolites of the kidneys in DN mice.A total of 51 differential metabolites were screened.Pathway analysis results indicated that nine pathways significantly changed between the control and model groups,while six pathways significantly altered between the model and JPGS groups.Pathways related to cysteine and methionine metabolism;alanine,tryptophan metabolism;aspartate and glutamate metabolism;and riboflavin metabolism were identified as the key pathways through which JPGS affects DN.Further experimental validation showed that JPGS treatment reduced the expression of TLR4/NF-κB/NLRP3 pathways and JNK/P38 pathway-mediated apoptosis related factors.CONCLUSION JPGS could markedly treat mice with streptozotocin(STZ)-induced DN,which is possibly related to the regulation of several metabolic pathways found in kidneys.Furthermore,JPGS could improve kidney inflammatory responses and ameliorate kidney injuries in DN mice via the TLR4/NF-κB/NLRP3 pathway and inhibit JNK/P38 pathwaymediated apoptosis in DN mice.

Targeting GPR65 alleviates hepatic inflammation and fibrosis by suppressing the JNK and NF-κB pathways

Background:G-protein coupled receptors(GPCRs)are recognized as attractive targets for drug therapy.However,it remains poorly understood how GPCRs,except for a few chemokine receptors,regulate the progression of liver fibrosis.Here,we aimed to reveal the role of GPR65,a proton-sensing receptor,in liver fibrosis and to elucidate the underlying mechanism.Methods:The expression level of GPR65 was evaluated in both human and mouse fibrotic livers.Furthermore,Gpr65-deficient mice were treated with either bile duct ligation(BDL)for 21 d or carbon tetrachloride(CCl4)for 8 weeks to investigate the role of GPR65 in liver fibrosis.A combination of experimental approaches,including Western blotting,quantitative real-time reverse transcription-polymerase chain reaction(qRT-PCR),and enzyme-linked immunosorbent assay(ELISA),confocal microscopy and rescue studies,were used to explore the underlying mechanisms of GPR65’s action in liver fibrosis.Additionally,the therapeutic potential of GPR65 inhibitor in the development of liver fibrosis was investigated.Results:We found that hepatic macrophage(HM)-enriched GPR65 was upregulated in both human and mouse fibrotic livers.Moreover,knockout of Gpr65 significantly alleviated BDL-and CCl4-induced liver inflammation,injury and fibrosis in vivo,and mouse bone marrow transplantation(BMT)experiments further demonstrated that the protective effect of Gpr65knockout is primarily mediated by bone marrow-derived macrophages(BMMs).Additionally,in vitro data demonstrated that Gpr65 silencing and GPR65 antagonist inhibited,while GPR65 overexpression and application of GPR65 endogenous and exogenous agonists enhanced the expression and release of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)and transforming growth factor-β(TGF-β),all of which subsequently promoted the activation of hepatic stellate cells(HSCs)and the damage of hepatocytes(HCs).Mechanistically,GPR65 overexpression,the acidic pH and GPR65 exogenous agonist induced up-regulation of TNF-αand IL-6 via the Gαq-Ca^(2+)-JNK/NF-κB pathways,while promoted the expression of TGF-βthrough the Gαq-Ca^(2+)-MLK3-MKK7-JNK pathway.Notably,pharmacological GPR65 inhibition retarded the development of inflammation,HCs injury and fibrosis invivo.Conclusions:GPR65 is a major regulator that modulates the progression of liver fibrosis.Thus,targeting GPR65 could be an effective therapeutic strategy for the prevention of liver fibrosis.

Exploring the role of N-acetyltransferases in diseases:a focus on N-acetyltransferase 9 in neurodegeneration

Acetyltransferases,required to transfer an acetyl group on protein are highly conserved proteins that play a crucial role in development and disease.Protein acetylation is a common post-translational modification pivotal to basic cellular processes.Close to 80%-90%of proteins are acetylated during translation,which is an irreversible process that affects protein structure,function,life,and localization.In this review,we have discussed the various N-acetyltransferases present in humans,their function,and how they might play a role in diseases.Furthermore,we have focused on N-acetyltransferase 9 and its role in microtubule stability.We have shed light on how N-acetyltransferase 9 and acetylation of proteins can potentially play a role in neurodegenerative diseases.We have specifically discussed the N-acetyltransferase 9-acetylation independent function and regulation of c-Jun N-terminal kinase signaling and microtubule stability during development and neurodegeneration.

Neuroprotective effects of Activin A on endoplasmic reticulum stress-mediated apoptotic and autophagic PC12 cell death

Activin A, a member of the transforming growth factor-beta superfamily, plays a neuroprotective role in multiple neurological diseases. Endoplasmic reticulum（ER） stress-mediated apoptotic and autophagic cell death is implicated in a wide range of diseases, including cerebral ischemia and neurodegenerative diseases. Thapsigargin was used to induce PC12 cell death, and Activin A was used for intervention. Our results showed that Activin A significantly inhibited morphological changes in thapsigargin-induced apoptotic cells, and the expression of apoptosis-associated proteins [cleaved-caspase-12, C/EBP homologous protein（CHOP） and cleaved-caspase-3] and biomarkers of autophagy（Beclin-1 and light chain 3）, and downregulated the expression of thapsigargin-induced ER stress-associated proteins [inositol requiring enzyme-1（IRE1）, tumor necrosis factor receptor-associated factor 2（TRAF2）, apoptosis signal-regulating kinase 1（ASK1）, c-Jun N-terminal kinase（JNK） and p38]. The inhibition of thapsigargin-induced cell death was concentration-dependent. These findings suggest that administration of Activin A protects PC12 cells against ER stress-mediated apoptotic and autophagic cell death by inhibiting the activation of the IRE1-TRAF2-ASK1-JNK/p38 cascade.

Anti-parkinsonian effects of octacosanol in 1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine-treated mice

Our previous research showed that octacosanol exerted its protective effects in 6-hydroxydopamine-induced Parkinsonian rats. The goal of this study was to investigate whether octacosanol would attenuate neurotoxicity in 1-methyl-4-phenyl-l,2,3,6 tetrahydropyridine （MPTP）-treated C57BL/6N mice and its potential mechanism. Behavioral tests, tyrosine hydroxylase immunohistochemistry and western blot were used to investigate the effects of octacosanol in a mouse model of Parkinson＇s disease. Oral administration of octacosanol （100 mg/kg） significantly improved behavioral impairments Jn mice treated by MPTP and markedly ameliorated morphological appearances of tyrosine hydroxylase-positive neuronal cells in the substantia nigra. Furthermore, octacosanol blocked MPTP-induced phosphorylation of p38MAPK and JNK, but not ERK1/2. These findings implicated that the protective effects afforded by octacosanol might be mediated by blocking the phosphorylation of p38MAPK and JNK on the signa transduction in vivo. Considering its excellent tolerability, octacosanol might be considered as a candidate agent for clinical application in treating Parkinson＇s disease.

Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

The human immunodeficiency virus type 1 （HIV-1） can interact with and exploit the host cellular machinery to replicate and propagate itself. Numerous studies have shown that the Mitogen-activated protein kinase （MAPK） signal pathway can positively regulate the replication of HIV-1, but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood. In this study, we used the Extracellular signal-regulated kinase （ERK） pathway inhibitor, PD98059, the Jun N-terminal kinase （JNK） pathway inhibitor, SP600125, and the p38 pathway inhibitor, SB203580, to investigate the roles of these pathways in HIV-1 replication. We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity. In addition, SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-INL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity. We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059 when cells were treated with all three MAPK pathway inhibitors in combination. Finally, we show that HIV-1 virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.