scholarly journals R-Fluoxetine Increases Melanin Synthesis Through a 5-HT1A/2A Receptor and p38 MAPK Signaling Pathways

2018 ◽  
Vol 20 (1) ◽  
pp. 80 ◽  
Author(s):  
Li Liu ◽  
Mengsi Fu ◽  
Siran Pei ◽  
Liangliang Zhou ◽  
Jing Shang
Keyword(s):  
P38 Mapk ◽  
Selective Serotonin Reuptake Inhibitors ◽  
Critical Role ◽  
Anxiolytic Effect ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Racemic Mixture ◽  
Melanin Synthesis ◽  
Mitogen Activated Protein

Fluoxetine, a member of the class of selective serotonin reuptake inhibitors, is a racemic mixture and has an anxiolytic effect in rodents. Previously, we have shown that fluoxetine can up-regulate melanin synthesis in B16F10 melanoma cells and normal human melanocytes (NMHM). However, the role of r-fluoxetine and s-fluoxetine, in the regulation of melanin synthesis, is still unknown. Here, we show how r-fluoxetine plays a critical role in fluoxetine enhancing melanogenesis, both in vivo and vitro, by up-regulating tyrosinase (TYR) and the microphthalmia-associated transcription factor (MITF) expression, whereas, s-fluoxetine does not show any effect in the vivo and vitro systems. In addition, we found that r-fluoxetine induced melanin synthesis through the serotonin1A receptor (5-HT1A) and serotonin 2A receptor (5-HT2A). Furthermore, r-fluoxetine increased the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), without affecting the phosphorylation of extracellularly responsive kinase (ERK1/2) and c-Jun N-terminal kinase (JNK). These data suggest that r-fluoxetine may be used as a drug for skin hypopigmentation disorders.

scholarly journals Phosphothreonine Lyase Promotes p65 Degradation in a Mitogen-Activated Protein Kinase/Mitogen- and Stress-Activated Protein Kinase 1-Dependent Manner

2018 ◽  
Vol 87 (1) ◽  
Author(s):  
Mingyu Hou ◽  
Wenhui Wang ◽  
Feizi Hu ◽  
Yuanxing Zhang ◽  
Dahai Yang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Pathogenic Bacteria ◽  
Critical Role ◽  
Nuclear Factor Κb ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Content Type ◽  
Catalytic Active Site ◽  
Mitogen Activated Protein

ABSTRACT Bacterial phosphothreonine lyases have been identified to be type III secretion system (T3SS) effectors that irreversibly dephosphorylate host mitogen-activated protein kinase (MAPK) signaling to promote infection. However, the effects of phosphothreonine lyase on nuclear factor κB (NF-κB) signaling remain largely unknown. In this study, we detected significant phosphothreonine lyase-dependent p65 degradation during Edwardsiella piscicida infection in macrophages, and this degradative effect was blocked by the protease inhibitor MG132. Further analysis revealed that phosphothreonine lyase promotes the dephosphorylation and ubiquitination of p65 by inhibiting the phosphorylation of mitogen- and stress-activated protein kinase-1 (MSK1) and by inhibiting the phosphorylation of extracellular signal-related kinase 1/2 (ERK1/2), p38α, and c-Jun N-terminal kinase (JNK). Moreover, we revealed that the catalytic active site of phosphothreonine lyase plays a critical role in regulating the MAPK-MSK1-p65 signaling axis. Collectively, the mechanism described here expands our understanding of the pathogenic effector in not only regulating MAPK signaling but also regulating p65. These findings uncover a new mechanism by which pathogenic bacteria overcome host innate immunity to promote pathogenesis.

scholarly journals APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Mapk Pathway ◽  
Adaptor Protein ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Scaffolding Protein ◽  
Mapk Activation ◽  
P38 Mapk Pathway ◽  
Mitogen Activated Protein

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

scholarly journals Elucidation on Predominant Pathways Involved in the Differentiation and Mineralization of Odontoblast-Like Cells by Selective Blockade of Mitogen-Activated Protein Kinases

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Jia Tang ◽  
Takashi Saito
Keyword(s):  
Cell Differentiation ◽  
Signaling Pathway ◽  
Critical Role ◽  
Mapk Signaling ◽  
Significant Inhibition ◽  
Mitogen Activated Protein Kinase ◽  
Alizarin Red ◽  
Selective Blockade ◽  
Alp Activity ◽  
Mitogen Activated Protein

Aim. To analyze the effect of three mitogen-activated protein kinase (MAPK) inhibitors, namely, SB202190 (p38 inhibitor), SP600125 (JNK inhibitor), and PD98059 (ERK inhibitor) in Dex-stimulated MDPC-23 cell differentiation and mineralization. Methods. Experiment was divided into five groups, control (cells without Dex and inhibitors treatment), Dex (cells with Dex treatment but without inhibitors), Dex + SB202190, Dex + SP600125, and Dex + PD98059. Cell differentiation was assessed by alkaline phosphatase (ALP) activity assay and real time RT-PCR. Cell mineralization was investigated by alizarin red staining. Results. Exposure to SB202190 (20 μM) significantly decreased the mineral deposition in Dex-treated cells as demonstrated by alizarin red staining. Treatment of SP600125 (20 μM) attenuated the mineralization as well, albeit at a lower degree as compared to SB202190 (20 μM). Similarly, SB202190 (20 μM) completely abrogated the ALP activity stimulated by Dex at six days in culture, while no changes were observed with regard to ALP activity in SP600125 (20 μM) and PD98059 (20 μM) treated cells. The upregulation of bone sialoprotein (BSP), ALP, and osteopontin (OPN) in Dex challenged cells was completely inhibited by SB202190. Conclusion. Blockade of p38-MAPK signaling pathway resulted in significant inhibition of ALP activity, mineralization, and downregulation of osteogenic markers. The data implicated that p38 signaling pathway plays a critical role in the regulation of MDPC-23 cells differentiation and mineralization.

scholarly journals ZEB1 suppression sensitizes KRAS mutant cancers to MEK inhibition by an IL17RD-dependent mechanism

2019 ◽  
Vol 11 (483) ◽  
pp. eaaq1238 ◽  
Author(s):  
David H. Peng ◽  
Samrat T. Kundu ◽  
Jared J. Fradette ◽  
Lixia Diao ◽  
Pan Tong ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Protein Kinase ◽  
Tumor Growth ◽  
Cancer Cells ◽  
Mapk Signaling ◽  
Lung Tumors ◽  
Mitogen Activated Protein Kinase ◽  
Mek Inhibition ◽  
Mitogen Activated Protein

Mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitors have failed to show clinical benefit in Kirsten rat sarcoma (KRAS) mutant lung cancer due to various resistance mechanisms. To identify differential therapeutic sensitivities between epithelial and mesenchymal lung tumors, we performed in vivo small hairpin RNA screens, proteomic profiling, and analysis of patient tumor datasets, which revealed an inverse correlation between mitogen-activated protein kinase (MAPK) signaling dependency and a zinc finger E-box binding homeobox 1 (ZEB1)–regulated epithelial-to-mesenchymal transition. Mechanistic studies determined that MAPK signaling dependency in epithelial lung cancer cells is due to the scaffold protein interleukin-17 receptor D (IL17RD), which is directly repressed by ZEB1. Lung tumors in multiple Kras mutant murine models with increased ZEB1 displayed low IL17RD expression, accompanied by MAPK-independent tumor growth and therapeutic resistance to MEK inhibition. Suppression of ZEB1 function with miR-200 expression or the histone deacetylase inhibitor mocetinostat sensitized resistant cancer cells to MEK inhibition and markedly reduced in vivo tumor growth, showing a promising combinatorial treatment strategy for KRAS mutant cancers. In human lung tumor samples, high ZEB1 and low IL17RD expression correlated with low MAPK signaling, presenting potential markers that predict patient response to MEK inhibitors.

scholarly journals The Expanding Role of p38 Mitogen-Activated Protein Kinase in Programmed Host Cell Death

2019 ◽  
Vol 12 ◽  
pp. 117863611986459 ◽  
Author(s):  
Jessica Gräb ◽  
Jan Rybniker
Keyword(s):  
Protein Kinase ◽  
Host Cell ◽  
P38 Mapk ◽  
Bacterial Infections ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Host Cell Apoptosis ◽  
Mitogen Activated Protein ◽  
P38 Mapk Inhibitors ◽  
Mapk Inhibitors

The p38 mitogen-activated protein kinase (MAPK) is involved in a multitude of essential cellular processes. The kinase is activated in response to environmental stresses, including bacterial infections and inflammation, to regulate the immune response of the host. However, recent studies have demonstrated that pathogens can manipulate p38 MAPK signaling for their own benefit to either prevent or induce host cell apoptosis. In addition, there is evidence demonstrating that p38 MAPK is a potent trigger of pathogen-induced necrosis driven by mitochondrial membrane disruption. Given the large number of p38 MAPK inhibitors that have been tested in clinical trials, these findings provide an opportunity to repurpose these drugs for improved control of infectious diseases.

scholarly journals Extracellular Signal-Regulated Kinase 2 Interacts with and Is Negatively Regulated by the LIM-Only Protein FHL2 in Cardiomyocytes

2004 ◽  
Vol 24 (3) ◽  
pp. 1081-1095 ◽  
Author(s):  
Nicole H. Purcell ◽  
Dina Darwis ◽  
Orlando F. Bueno ◽  
Judith M. Müller ◽  
Roland Schüle ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Erk Signaling ◽  
Interacting Protein ◽  
Hypertrophic Response ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

ABSTRACT The mitogen-activated protein kinase (MAPK) signaling pathway regulates diverse biologic functions including cell growth, differentiation, proliferation, and apoptosis. The extracellular signal-regulated kinases (ERKs) constitute one branch of the MAPK pathway that has been implicated in the regulation of cardiac differentiated growth, although the downstream mechanisms whereby ERK signaling affects this process are not well characterized. Here we performed a yeast two-hybrid screen with ERK2 bait and a cardiac cDNA library to identify novel proteins involved in regulating ERK signaling in cardiomyocytes. This screen identified the LIM-only factor FHL2 as an ERK interacting protein in both yeast and mammalian cells. In vivo, FHL2 and ERK2 colocalized in the cytoplasm at the level of the Z-line, and interestingly, FHL2 interacted more efficiently with the activated form of ERK2 than with the dephosphorylated form. ERK2 also interacted with FHL1 and FHL3 but not with the muscle LIM protein. Moreover, at least two LIM domains in FHL2 were required to mediate efficient interaction with ERK2. The interaction between ERK2 and FHL2 did not influence ERK1/2 activation, nor was FHL2 directly phosphorylated by ERK2. However, FHL2 inhibited the ability of activated ERK2 to reside within the nucleus, thus blocking ERK-dependent transcriptional responsiveness of ELK-1, GATA4, and the atrial natriuretic factor promoter. Finally, FHL2 partially antagonized the cardiac hypertrophic response induced by activated MEK-1, GATA4, and phenylephrine agonist stimulation. Collectively, these results suggest that FHL2 serves a repressor function in cardiomyocytes through its ability to inhibit ERK1/2 transcriptional coupling.

Phosphorylation of Argonaute 2 at serine-387 facilitates its localization to processing bodies

2008 ◽  
Vol 413 (3) ◽  
pp. 429-436 ◽  
Author(s):  
Yan Zeng ◽  
Heidi Sankala ◽  
Xiaoxiao Zhang ◽  
Paul R. Graves
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Phosphorylation Site ◽  
Mitogen Activated Protein Kinase ◽  
Processing Bodies ◽  
Mitogen Activated Protein

Ago (Argonaute) proteins are essential effectors of RNA-mediated gene silencing. To explore potential regulatory mechanisms for Ago proteins, we examined the phosphorylation of human Ago2. We identified serine-387 as the major Ago2 phosphorylation site in vivo. Phosphorylation of Ago2 at serine-387 was significantly induced by treatment with sodium arsenite or anisomycin, and arsenite-induced phosphorylation was inhibited by a p38 MAPK (mitogen-activated protein kinase) inhibitor, but not by inhibitors of JNK (c-Jun N-terminal kinase) or MEK [MAPK/ERK (extracellular-signal-regulated kinase) kinase]. MAPKAPK2 (MAPK-activated protein kinase-2) phosphorylated bacterially expressed full-length human Ago2 at serine-387 in vitro, but not the S387A mutant. Finally, mutation of serine-387 to an alanine residue or treatment of cells with a p38 MAPK inhibitor reduced the localization of Ago2 to processing bodies. These results suggest a potential regulatory mechanism for RNA silencing acting through Ago2 serine-387 phosphorylation mediated by the p38 MAPK pathway.

p38 MAPK Signaling Mediates Retinoic Acid-Induced Expression of a Novel Tumor Suppressor Protein Programmed Cell Death 4 (PDCD4) in Acute Promyelocytic Leukemia Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1942-1942
Author(s):  
Ugur Akar ◽  
Bulent Ozpolat ◽  
Nancy Colburn ◽  
Gabriel Lopez-Berestein
Keyword(s):  
Retinoic Acid ◽  
Cell Differentiation ◽  
P38 Mapk ◽  
Myeloid Cell ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Granulocytic Differentiation ◽  
P38 Inhibitor ◽  
Pdcd4 Expression ◽  
Mitogen Activated Protein

Abstract Programmed-cell-death-4 (PDCD4) is a novel tumor suppressor protein that suppresses tumor promoter-induced neoplastic transformation. PDCD4 specifically inhibits the helicase activity of eukaryotic translation initiation factor 4A (eIF4A) and translation initiation and cap-dependent mRNA translation in vitro and in vivo. Loss or underexpression of PDCD4 is associated with carcinogenesis and chemoresistance in solid tumors. The role and regulation of PDCD4 in the the hematopoietic system and myeloid leukemia cells are not known. We previously reported that ATRA induces translational suppression through multiple posttranscriptional mechanisms during terminal cell differentiation (Harris et al, Blood, 104 (5) 2004). Therefore, in this study, we investigated the expression and regulation of PDCD4 during myeloid cell differentiation. All-trans-retinoic acid (ATRA) induces terminal differentiation in acute myeloid leukemia (AML) and promyelocytic (APL) cells, a well established model for myeloid cell differentiation. We found that treatment of HL60 (M2 type AML) and NB4 APL (M3 type AML) cells with ATRA (1 mM) induced PDCD4 protein and mRNA expression during granulocytic differentiation detected by western blot and RT-PCR analysis, respectively. We also demonstrated that inhibition of PDCD4 by siRNA reduced granulocytic differentiation induced by ATRA, suggesting that PDCD4 plays a role in granuliocytic differentiation. To determine mechanisms regulating PDCD4 we investigated the role of pP38 MAPK (Mitogen activated protein kinase) in reugulation of PDCD4 expression. ATRA induced PDCD4 expression correlated with activation of p38 MAPK (Mitogen Activated Protein Kinase) pathway in NB4 cells. To test the hypothesis that p38 MAPK signaling pathway mediates retinoic acid induced PDCD4 expression we treated cells with a specific p38 MAPK inhibitor, SB203580, ATRA or combination with ATRA. We observed that p38 inhibitor inhibited ATRA-induced expression of PDCD4 in NB4 cells. Basal level of PDCD4 expression was also markedly downregulated in the presence of p38 inhibitor when compared to untreated control cells, suggesting that p38 pathway is involved in ATRA-dependent and independent PDCD4 expression. Currently we are investigating whether inhibition of p38 by small interfering RNA (siRNA) will prevent expression of ATRA induced PDCD4 in APL cells. We are also trying to identify whether ATF2 transcription factor, a downstream of p38, is involved in PDCD4 expression. p38-mediated induction of PDCD4 pathway reveals a novel mechanism of PDCD4 regulation and ATRA action, providing a new insight into understanding terminal differentiation of myeloid cells. Better understanding the role of PDCD4 and posttranscriptional control of gene expression may offer targets for the differentiation therapy and chemo preventive strategies.

Mitigation of Direct Neurotoxic Effects of Lidocaine and Amitriptyline by Inhibition of p38 Mitogen-activated Protein Kinase In Vitro  and In Vivo 

2006 ◽  
Vol 104 (6) ◽  
pp. 1266-1273 ◽  
Author(s):  
Philipp Lirk ◽  
Ingrid Haller ◽  
Robert R. Myers ◽  
Lars Klimaschewski ◽  
Yi-Chuan Kau ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
P38 Mapk ◽  
Local Anesthetic ◽  
Apoptotic Cell ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
P38 Mapk Inhibitor ◽  
Mapk Inhibitor

Background Local anesthetic-induced direct neurotoxicity (paresthesia, failure to regain normal sensory and motor function) is a potentially devastating complication of regional anesthesia. Local anesthetics activate the p38 mitogen-activated protein kinase (MAPK) system, which is involved in apoptotic cell death. The authors therefore investigated in vitro (cultured primary sensory neurons) and in vivo (sciatic nerve block model) the potential neuroprotective effect of the p38 MAPK inhibitor SB203580 administered together with a clinical (lidocaine) or investigational (amitriptyline) local anesthetic. Methods Cell survival and mitochondrial depolarization as marker of apoptotic cell death was assessed in rat dorsal root ganglia incubated with lidocaine or amitriptyline either with or without the addition of SB203580. Similarly, in a sciatic nerve block model, the authors assessed wallerian degeneration by light microscopy to detect a potential mitigating effect of MAPK inhibition. Results Lidocaine at 40 mm/approximately 1% and amitriptyline at 100 microm reduce neuron count, but coincubation with the p38 MAPK inhibitor SB203580 at 10 mum significantly reduces cytotoxicity and the number of neurons exhibiting mitochondrial depolarization. Also, wallerian degeneration and demyelination induced by lidocaine (600 mm/approximately 15%) and amitriptyline (10 mm/approximately 0.3%) seem to be mitigated by SB203580. Conclusions The cytotoxic effect of lidocaine and amitriptyline in cultured dorsal root ganglia cells and the nerve degeneration in the rat sciatic nerve model seem, at least in part, to be mediated by apoptosis but seem efficiently blocked by an inhibitor of p38 MAPK, making it conceivable that coinjection might be useful in preventing local anesthetic-induced neurotoxicity.

scholarly journals MKP-3 Has Essential Roles as a Negative Regulator of the Ras/Mitogen-Activated Protein Kinase Pathway during Drosophila Development

2004 ◽  
Vol 24 (2) ◽  
pp. 573-583 ◽  
Author(s):  
Myungjin Kim ◽  
Guang-Ho Cha ◽  
Sunhong Kim ◽  
Jun Hee Lee ◽  
Jeehye Park ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cell Fate ◽  
Photoreceptor Cells ◽  
Mapk Signaling ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Loss Of Function ◽  
Wing Vein ◽  
Mitogen Activated Protein

ABSTRACT Mitogen-activated protein kinase (MAPK) phosphatase 3 (MKP-3) is a well-known negative regulator in the Ras/extracellular signal-regulated kinase (ERK)-MAPK signaling pathway responsible for cell fate determination and proliferation during development. However, the physiological roles of MKP-3 and the mechanism by which MKP-3 regulates Ras/Drosophila ERK (DERK) signaling in vivo have not been determined. Here, we demonstrated that Drosophila MKP-3 (DMKP-3) is critically involved in cell differentiation, proliferation, and gene expression by suppressing the Ras/DERK pathway, specifically binding to DERK via the N-terminal ERK-binding domain of DMKP-3. Overexpression of DMKP-3 reduced the number of photoreceptor cells and inhibited wing vein differentiation. Conversely, DMKP-3 hypomorphic mutants exhibited extra photoreceptor cells and wing veins, and its null mutants showed striking phenotypes, such as embryonic lethality and severe defects in oogenesis. All of these phenotypes were highly similar to those of the gain-of-function mutants of DERK/rl. The functional interaction between DMKP-3 and the Ras/DERK pathway was further confirmed by genetic interactions between DMKP-3 loss-of-function mutants or overexpressing transgenic flies and various mutants of the Ras/DERK pathway. Collectively, these data provide the direct evidences that DMKP-3 is indispensable to the regulation of DERK signaling activity during Drosophila development.

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