scholarly journals AICAR activates AMPK to regulate STAT3 nuclear translocation and phosphorylation and iNOS expression in inflammatory pain

2020 ◽  
Author(s):  
Hongchun Xiang ◽  
Guo-Wei Cai ◽  
Liang Hu ◽  
He Zhu ◽  
Lixue Lin ◽  
...  
Keyword(s):  
Inflammatory Pain ◽  
Nuclear Translocation ◽  
Mitochondrial Damage ◽  
Ros Generation ◽  
Ampk Activation ◽  
Signal Transducers ◽  
Stat3 Phosphorylation ◽  
Ros Accumulation ◽  
Amp Activated Protein Kinase ◽  
Transcription 3

Abstract Background: AMP-activated protein kinase (AMPK) activators can improve inflammatory pain and neuropathic pain. Inflammation translocate signal transducers and activators of transcription 3 (STAT3) to the nuclei of activated macrophages, and STAT3 phosphorylation promotes the expression of inducible nitric oxide synthetase (iNOS). In this study, we determined whether AMPK activation alleviate inflammatory pain via STAT3 nuclear translocation and phosphorylation. Methods: Immunoblotting was used to measure the expression of p-AMPK, and iNOS. Immunoblotting and immunofluorescence were used to detect the nuclear translocation of p-STAT3(Ser727) and STAT3 in macrophages of local inflammatory tissues. Flow cytometry was used to measure reactive oxygen species (ROS) accumulation and mitochondrial damage.Results: AMPK activation with AICAR significantly alleviated pain hypersensitivity and inhibited the expression of iNOS in complete Freund's adjust (CFA)-induced inflamed skin tissues. CFA caused nuclear translocation of STAT3 and p-STAT3(Ser727) in macrophages of inflamed skin tissues. AICAR inhibited nuclear translocation of STAT3 and p-STAT3(Ser727) and promoted the phosphorylation of STAT3(Ser727) in the cytoplasm of macrophages. AICAR also inhibited the expression of iNOS and nuclear translocation of STAT3 and p-STAT3(Ser727), and promoted the phosphorylation of STAT3(Ser727) in NR8383 macrophages treated with CFA. AMPK activation also inhibited the ROS generation and the mitochondrial damage of NR8383 macrophages caused by CFA. In addition, transfection of STAT3 S727D decreased ROS and alleviated mitochondrial damage.Conclusions: Activation of AMPK attenuates inflammatory pain and suppresses STAT3 nuclear translocation and phosphorylation of STAT3(Ser727) in macrophages, resulting in reduced iNOS. Activation of AMPK also promotes phosphorylation of STAT3(Ser727) in the cytoplasm of macrophages to alleviate ROS accumulation and mitochondrial damage associated with inflammation.

scholarly journals Angiopoietin-Like Growth Factor Involved in Leptin Signaling in the Hypothalamus

2021 ◽  
Vol 22 (7) ◽  
pp. 3443
Author(s):  
Yunseon Jang ◽  
Jun Young Heo ◽  
Min Joung Lee ◽  
Jiebo Zhu ◽  
Changjun Seo ◽  
...  
Keyword(s):  
Growth Factor ◽  
Brain Regions ◽  
Whole Body ◽  
Signal Transducers ◽  
Leptin Signaling ◽  
Stat3 Phosphorylation ◽  
Hypothalamic Regulation ◽  
Induced Signal ◽  
Body Energy ◽  
Transcription 3

The hypothalamic regulation of appetite governs whole-body energy balance. Satiety is regulated by endocrine factors including leptin, and impaired leptin signaling is associated with obesity. Despite the anorectic effect of leptin through the regulation of the hypothalamic feeding circuit, a distinct downstream mediator of leptin signaling in neuron remains unclear. Angiopoietin-like growth factor (AGF) is a peripheral activator of energy expenditure and antagonizes obesity. However, the regulation of AGF expression in brain and localization to mediate anorectic signaling is unknown. Here, we demonstrated that AGF is expressed in proopiomelanocortin (POMC)-expressing neurons located in the arcuate nucleus (ARC) of the hypothalamus. Unlike other brain regions, hypothalamic AGF expression is stimulated by leptin-induced signal transducers and activators of transcription 3 (STAT3) phosphorylation. In addition, leptin treatment to hypothalamic N1 cells significantly enhanced the promoter activity of AGF. This induction was abolished by the pretreatment of ruxolitinib, a leptin signaling inhibitor. These results indicate that hypothalamic AGF expression is induced by leptin and colocalized to POMC neurons.

scholarly journals Suppression of STAT3 Phosphorylation and RelA/p65 Acetylation Mediated by MicroRNA134 Plays a Pivotal Role in the Apoptotic Effect of Lambertianic Acid

2019 ◽  
Vol 20 (12) ◽  
pp. 2993 ◽  
Author(s):  
Deok Yong Sim ◽  
Hyo-Jung Lee ◽  
Ji Hoon Jung ◽  
Eunji Im ◽  
Jisung Hwang ◽  
...  
Keyword(s):  
Nuclear Translocation ◽  
Parp Cleavage ◽  
Signal Transducers ◽  
Stat3 Phosphorylation ◽  
Apoptotic Effect ◽  
Lambertianic Acid ◽  
Du145 Cells ◽  
Induced Apoptosis ◽  
Factor Α ◽  
Mcf 7

As p300-mediated RelA/p65 hyperacetylation by signal transducers and activators of transcription 3 (STAT3) is critical for NF-κB activation, in the current study, the apoptotic mechanism of lambertianic acid (LA) was explored in relation to STAT3 phosphorylation and RelA/p65 acetylation in MCF-7, DU145, PC-3, and MDA-MB-453 cells. LA significantly increased the cytotoxicity, sub G 1 population, and the cleavage of poly (ADP-ribose) polymerase (PARP) in MDA-MB-453 or PC-3 cells (STAT3 mutant), more than in the MCF-7 or DU145 cells (STAT3 wild). Consistently, LA inhibited the phosphorylation of STAT3 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and disrupted the interaction between p-STAT3, p300, NF-κB, and RelA/p65 acetylation (Ac-RelA/p65) in the MCF-7 and DU145 cells. Also, LA reduced the nuclear translocation of STAT3 and NF-κB via their colocalization, and also suppressed the protein expression of XIAP, survivin, Bcl-2, Bcl-xL, vascular endothelial growth factor (VEGF), Cox-2, c-Myc and mRNA expression of interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) in MCF-7 cells. Conversely, IL-6 blocked the ability of LA to suppress the cytotoxicity and PARP cleavage, while the depletion of STAT3 or p300 enhanced the PARP cleavage of LA in the MCF-7 cells. Notably, LA upregulated the level of miRNA134 and so miRNA134 mimic attenuated the expression of pro-PARP, p-STAT3, and Ac-RelA, while the miRNA134 inhibitor reversed the ability of LA to reduce the expression of Ac-RelA and pro-PARP in MCF-7 cells. Overall, these findings suggest that LA induced apoptosis via the miRNA-134 mediated inhibition of STAT3 and RelA/p65 acetylation.

scholarly journals AMP-activated protein kinase (AMPK) activation inhibits nuclear translocation of Smad4 in mesangial cells and diabetic kidneys

2015 ◽  
Vol 308 (10) ◽  
pp. F1167-F1177 ◽  
Author(s):  
Jinghong Zhao ◽  
Satoshi Miyamoto ◽  
Young-Hyun You ◽  
Kumar Sharma
Keyword(s):  
Kidney Disease ◽  
Diabetic Kidney Disease ◽  
Nuclear Translocation ◽  
Mesangial Cells ◽  
Nuclear Accumulation ◽  
Ampk Activation ◽  
Mesangial Matrix ◽  
Diabetic Kidney ◽  
Amp Activated Protein Kinase ◽  
Stimulation Of

Diabetic nephropathy is characterized by diffuse mesangial matrix expansion and is largely dependent on the TGF-β/Smad signaling pathway. Smad4 is required for TGF-β signaling; however, its regulation has not been well characterized in diabetic kidney disease. Here, we report that high glucose is sufficient to stimulate nuclear translocation of Smad4 in mesangial cells and that stimulation of the major energy sensor AMP-activated protein kinase (AMPK) has a potent effect to block Smad4 nuclear translocation. Activation of AMPK by 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) inhibited high glucose-induced and TGF-β stimulation of nuclear Smad4. To identify which of the catalytic α-subunits may be involved, small interfering (si) RNA-based inhibition of AMPK α1- or α2-subunit was employed. Inhibition of either subunit reduced overall AMPK activity and contributed to Smad4 nuclear accumulation. In an animal model of early diabetic kidney disease, induction of diabetes was found to markedly stimulate Smad4 protein levels and enhance nuclear accumulation. AMPK activation with AICAR completely prevented the upregulation of Smad4 and reduced mesangial matrix accumulation. We conclude that stimulation of Smad4 in cell culture and in in vivo models of early diabetic kidney disease is dependent on AMPK.

scholarly journals Acacetin Inhibits the Growth of STAT3-Activated DU145 Prostate Cancer Cells by Directly Binding to Signal Transducer and Activator of Transcription 3 (STAT3)

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6204
Author(s):  
Sun Yun ◽  
Yu-Jin Lee ◽  
Jiyeon Choi ◽  
Nam Doo Kim ◽  
Dong Cho Han ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Nuclear Translocation ◽  
Critical Role ◽  
Cancer Drug ◽  
Dependent Manner ◽  
Signal Transducer ◽  
Prostate Cancer Cells ◽  
Stat3 Phosphorylation ◽  
Transcription 3

Signal transducer and activator of transcription 3 (STAT3) plays a critical role in the formation and growth of human cancer. Therefore, STAT3 is a therapeutic target for cancer drug discovery. Acacetin, a flavone present in various plants, inhibits constitutive and inducible STAT3 activation in STAT3-activated DU145 prostate cancer cells. Acacetin inhibits STAT3 activity by directly binding to STAT3, which we confirmed by a pull-down assay with a biotinylated compound and two level-free methods, namely, a drug affinity responsive target stability (DARTS) experiment and a cellular thermal shift assay (CETSA). Acacetin inhibits STAT3 phosphorylation at the tyrosine 705 residue and nuclear translocation in DU145 cells, which leads to the downregulation of STAT3 target genes. Acacetin then induces apoptosis in a time-dependent manner. Interestingly, acacetin induces the production of reactive oxygen species (ROS) that are not involved in the acacetin-induced inhibition of STAT3 activation because the suppressed p-STAT3 level is not rescued by treatment with GSH or NAC, which are general ROS inhibitors. We also found that acacetin inhibits tumor growth in xenografted nude mice. These results suggest that acacetin, as a STAT3 inhibitor, could be a possible drug candidate for targeting STAT3 for the treatment of cancer in humans.

scholarly journals β2-adrenergic receptor agonist counteracts skeletal muscle atrophy and oxidative stress in uremic mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takaaki Higashihara ◽  
Hiroshi Nishi ◽  
Koji Takemura ◽  
Hiroshi Watanabe ◽  
Toru Maruyama ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adrenergic Receptor ◽  
Culture Media ◽  
Therapeutic Interventions ◽  
Skeletal Muscle Atrophy ◽  
C2c12 Myotubes ◽  
Ros Generation ◽  
Skeletal Muscle Function ◽  
Ros Accumulation ◽  
Β2 Adrenergic Receptor

AbstractIn patients with chronic kidney disease, skeletal muscle dysfunction is associated with mortality. Uremic sarcopenia is caused by ageing, malnutrition, and chronic inflammation, but the molecular mechanism and potential therapeutics have not been fully elucidated yet. We hypothesize that accumulated uremic toxins might exert a direct deteriorative effect on skeletal muscle and explore the pharmacological treatment in experimental animal and culture cell models. The mice intraperitoneally injected with indoxyl sulfate (IS) after unilateral nephrectomy displayed an elevation of IS concentration in skeletal muscle and a reduction of instantaneous muscle strength, along with the predominant loss of fast-twitch myofibers and intramuscular reactive oxygen species (ROS) generation. The addition of IS in the culture media decreased the size of fully differentiated mouse C2C12 myotubes as well. ROS accumulation and mitochondrial dysfunction were also noted. Next, the effect of the β2-adrenergic receptor (β2-AR) agonist, clenbuterol, was evaluated as a potential treatment for uremic sarcopenia. In mice injected with IS, clenbuterol treatment increased the muscle mass and restored the tissue ROS level but failed to improve muscle weakness. In C2C12 myotubes stimulated with IS, although β2-AR activation also attenuated myotube size reduction and ROS accumulation as did other anti-oxidant reagents, it failed to augment the mitochondrial membrane potential. In conclusion, IS provokes muscular strength loss (uremic dynapenia), ROS generation, and mitochondrial impairment. Although the β2-AR agonist can increase the muscular mass with ROS reduction, development of therapeutic interventions for restoring skeletal muscle function is still awaited.

scholarly journals Preconditioning Mediated by Sublethal Oxygen—Glucose Deprivation-Induced Cyclooxygenase-2 Expression via the Signal Transducers and Activators of Transcription 3 Phosphorylation

2008 ◽  
Vol 28 (7) ◽  
pp. 1329-1340 ◽  
Author(s):  
Eun J Kim ◽  
Ami P Raval ◽  
Miguel A Perez-Pinzon
Keyword(s):  
Glucose Deprivation ◽  
Cyclooxygenase 2 ◽  
Serine Phosphorylation ◽  
Signaling Cascade ◽  
Oxygen Glucose Deprivation ◽  
Signal Transducers ◽  
Extracellular Signal ◽  
Cox 2 ◽  
Transcription 3 ◽  
Signal Transducers And Activators

The signal transducers and activators of transcription (STATs) were found to be essential for cardioprotection. However, their role in preconditioning (PC) neuroprotection remains undefined. Previously, our studies showed that PC mediated a signaling cascade that involves activation of epsilon protein kinase C (εPKC), extracellular signal-regulated kinase (ERK1/2), and cyclooxygenase-2 (COX-2) pathways. However, the intermediate pathway by which ERK1/2 activates COX-2 was not defined. In this study, we investigated whether the PC-induced signaling pathway requires phosphorylation of STAT isoforms for COX-2 expression. To mimic PC or lethal ischemia, mixed cortical neuron/astrocyte cell cultures were subjected to 1 and/or 4 h of oxygen—glucose deprivation (OGD), respectively. The results indicated serine phosphorylation of STAT3 after PC or εPKC activation. Inhibition of either εPKC or ERK1/2 activation abolished PC-induced serine phosphorylation of STAT3. Additionally, inhibition of STAT3 prevented PC-induced COX-2 expression and neuroprotection against OGD. Therefore, our findings suggest that PC signaling cascade involves STAT3 activation after εPKC and ERK1/2 activation. Finally, we show that STAT3 activation mediates COX-2 expression and ischemic tolerance.

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