scholarly journals Indoxyl Sulfate Induces Apoptosis Through Oxidative Stress and Mitogen-Activated Protein Kinase Signaling Pathway Inhibition in Human Astrocytes

2019 ◽  
Vol 8 (2) ◽  
pp. 191 ◽  
Author(s):  
Yi-Ting Lin ◽  
Ping-Hsun Wu ◽  
Yi-Chun Tsai ◽  
Ya-Ling Hsu ◽  
Han Ying Wang ◽  
...  

Uremic toxins accumulated in chronic kidney disease (CKD) increases the risk of cognitive impairment. Indoxyl sulfate (IS) is a well-known protein-bound uremic toxin that is correlated with several systemic diseases, but no studies on human brain cells are available. We investigated the effect of IS on primary human astrocytes through next-generation sequencing and cell experiment confirmation to explore the mechanism of IS-associated brain damage. Total RNAs extracted from IS-treated and control astrocytes were evaluated by performing functional and pathway enrichment analysis. The toxicities of IS in the astrocytes were investigated in terms of cell viability through flow cytometry; the signal pathway was then investigated through immunoblotting. IS stimulated the release of reactive oxygen species, increased nuclear factor (erythroid-derived 2)-like 2 levels, and reduced mitochondrial membrane potential. IS triggered astrocyte apoptosis by inhibiting the mitogen-activated protein kinase (MAPK) pathway, including extracellular-signal-regulated kinase (ERK), MAPK/ERK kinase, c-Jun N-terminal kinase, and p38. The decreased ERK phosphorylation was mediated by the upregulated dual-specificity phosphatase 1, 5, 8, and 16. In conclusion, IS can induce neurotoxicity in patients with CKD and the pathogenesis involves cell apoptosis through oxidative stress induction and MAPK pathway inhibition in human astrocytes.

2012 ◽  
Vol 90 (5) ◽  
pp. 655-662 ◽  
Author(s):  
Xiao Cui Lv ◽  
Hai Yan Zhou

Recently, many studies have attempted to illustrate the mechanism of autophagy in protection against oxidative stress to the heart induced by H2O2. However, whether resveratrol-induced autophagy involves the p38 mitogen-activated protein kinase (MAPK) pathway is still unknown. This study aimed to investigate whether treating H9c2 cells with resveratrol increases autophagy and attenuates the cell death and apoptosis induced by oxidative stress via the p38 MAPK pathway. Resveratrol with or without SB202190, an inhibitor of the p38 MAPK pathway, was added 30 min before H2O2. After H2O2 treatment, the cells were incubated under 5% CO2 at 37 °C for 24 h to assess cell survival and death or incubated for 20 min for Western blot and transmission electron microscopy. Flow cytometry was used to detect apoptosis after 6 h of H2O2 treatment. Resveratrol at 20 µmol/L protected H9c2 cells treated with 100 µmol/L H2O2 from oxidative damage. It increased cell survival and markedly decrease lactate dehydrogenase release. In addition, resveratrol increased autophagy and decreased H2O2-induced apoptosis. Furthermore, the protective effects of resveratrol were inhibited by 10 µmol/L SB202190. Thus, resveratrol protected H2O2-treated H9c2 cells by upregulating autophagy via the p38 MAPK pathway.


1998 ◽  
Vol 3 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Kathryn Z Guyton ◽  
Myriani Gorospe ◽  
Xiantao Wang ◽  
Yolanda D Mock ◽  
Gertrude C Kokkonen ◽  
...  

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jackson Peterson ◽  
Siqi Li ◽  
Erin Kaltenbrun ◽  
Ozgun Erdogan ◽  
Christopher M. Counter

AbstractThe ability to translate three nucleotide sequences, or codons, into amino acids to form proteins is conserved across all organisms. All but two amino acids have multiple codons, and the frequency that such synonymous codons occur in genomes ranges from rare to common. Transcripts enriched in rare codons are typically associated with poor translation, but in certain settings can be robustly expressed, suggestive of codon-dependent regulation. Given this, we screened a gain-of-function library for human genes that increase the expression of a GFPrare reporter encoded by rare codons. This screen identified multiple components of the mitogen activated protein kinase (MAPK) pathway enhancing GFPrare expression. This effect was reversed with inhibitors of this pathway and confirmed to be both codon-dependent and occur with ectopic transcripts naturally coded with rare codons. Finally, this effect was associated, at least in part, with enhanced translation. We thus identify a potential regulatory module that takes advantage of the redundancy in the genetic code to modulate protein expression.


2004 ◽  
pp. 233-240 ◽  
Author(s):  
AM Nanzer ◽  
S Khalaf ◽  
AM Mozid ◽  
RC Fowkes ◽  
MV Patel ◽  
...  

OBJECTIVES: Ghrelin is a brain-gut peptide with GH-releasing and appetite-inducing activities and a widespread tissue distribution. Ghrelin is the endogenous ligand of the GH secretagogue receptor type 1a (GHS-R1a), and both ghrelin and the GHS-R1a are expressed in the pituitary. There are conflicting data regarding the effects of ghrelin on cell proliferation. A positive effect on proliferation and activation of the mitogen-activated protein kinase (MAPK) pathway has been found in hepatoma, adipose, cardiomyocyte and prostate cell lines. However, ghrelin has also been shown to have anti-proliferative effects on breast, lung and thyroid cell lines. We therefore examined the effect of ghrelin on the rat pituitary cell line GH3. METHODS: RT-PCR was used for the detection of GHS-R1a and pre-proghrelin mRNA expression in GH3 cells. The effect of ghrelin on cell proliferation was studied using [(3)H]thymidine incorporation; cell counting and the activation of the MAPK pathway were studied using immunoblotting and inhibitors of the extracellular signal-regulated kinase 1 and 2 (ERK 1/2), protein kinase C (PKC) and tyrosine phosphatase pathways. RESULTS: GHS-R1a and ghrelin mRNA expression were detected in GH3 cells. Ghrelin, at 10(-10) to 10(-6) M concentrations, significantly increased [(3)H]thymidine incorporation (at 10(-9) M, 183+/-13% (means+/-s.e.m.) compared with untreated controls), while 12-phorbol 13-myristate acetate (PMA) at 10(-7) M (used as a positive control) caused a 212+/-14% increase. A reproducible stimulatory effect of desoctanoyl ghrelin was also observed on [(3)H]thymidine incorporation (135+/-5%; P<0.01 at 10(-9) M compared with control), as well as on the cell count (control 6.8 x 10(4)+/-8.7 x 10(3) cells/ml vs desoctanoyl ghrelin (10(-9) M) 1.04 x 10(5)+/-7.5 x 10(3) cells/ml; P<0.01). Ghrelin caused a significant increase in phosphorylated ERK 1/2 in immunoblotting, while desoctanoyl ghrelin showed a smaller but also significant stimulatory effect. The positive effect of ghrelin and desoctanoyl ghrelin on [(3)H]thymidine incorporation was abolished by the MAPK kinase inhibitor U0126, the PKC inhibitor GF109203X and the tyrosine kinase inhibitor tyrphostin 23, suggesting that the ghrelin-induced cell proliferation of GH3 cells is mediated both via a PKC-MAPK-dependent pathway and via a tyrosine kinase-dependent pathway. This could also be clearly demonstrated by Western blot analysis, where a transient increase in ERK 1/2 phosphorylation by ghrelin was attenuated by all three inhibitors. CONCLUSION: We have shown a novel role for ghrelin in stimulating the proliferation of a somatotroph pituitary tumour cell line, suggesting that ERK activation is involved in mediating the effects of ghrelin on cell proliferation. Desoctanoyl ghrelin showed a similar effect. As ghrelin has been shown to be expressed in both normal and adenomatous pituitary tissue, locally produced ghrelin may play a role in pituitary tumorigenesis via an autocrine/paracrine pathway.


2004 ◽  
Vol 381 (2) ◽  
pp. 437-446 ◽  
Author(s):  
Anderson A. ANDRADE ◽  
Patrícia N. G. SILVA ◽  
Anna C. T. C. PEREIRA ◽  
Lirlândia P. de SOUSA ◽  
Paulo C. P. FERREIRA ◽  
...  

Early events play a decisive role in virus multiplication. We have shown previously that activation of MAPK/ERK1/2 (mitogen-activated protein kinase/extracellular-signal-regulated kinase 1/2) and protein kinase A are pivotal for vaccinia virus (VV) multiplication [de Magalhães, Andrade, Silva, Sousa, Ropert, Ferreira, Kroon, Gazzinelli and Bonjardim (2001) J. Biol. Chem. 276, 38353–38360]. In the present study, we show that VV infection provoked a sustained activation of both ERK1/2 and RSK2 (ribosomal S6 kinase 2). Our results also provide evidence that this pattern of kinase activation depends on virus multiplication and ongoing protein synthesis and is maintained independently of virus DNA synthesis. It is noteworthy that the VGF (VV growth factor), although involved, is not essential for prolonged ERK1/2 activation. Furthermore, our findings suggest that the VV-stimulated ERK1/2 activation also seems to require actin dynamics, microtubule polymerization and tyrosine kinase phosphorylation. The VV-stimulated pathway MEK/ERK1/2/RSK2 (where MEK stands for MAPK/ERK kinase) leads to phosphorylation of the ternary complex factor Elk-1 and expression of the early growth response (egr-1) gene, which kinetically paralleled the kinase activation. The recruitment of this pathway is biologically relevant, since its disruption caused a profound effect on viral thymidine kinase gene expression, viral DNA replication and VV multiplication. This pattern of sustained kinase activation after VV infection is unique. In addition, by connecting upstream signals generated at the cytoskeleton and by tyrosine kinase, the MEK/ERK1/2/RSK2 cascade seems to play a decisive role not only at early stages of the infection, i.e. post-penetration, but is also crucial to define the fate of virus progeny.


2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong

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.


2002 ◽  
Vol 22 (20) ◽  
pp. 6931-6945 ◽  
Author(s):  
Ole Morten Seternes ◽  
Bjarne Johansen ◽  
Beate Hegge ◽  
Mona Johannessen ◽  
Stephen M. Keyse ◽  
...  

ABSTRACT The p38 mitogen-activated protein kinase (MAPK) pathway is an important mediator of cellular responses to environmental stress. Targets of p38 include transcription factors, components of the translational machinery, and downstream serine/threonine kinases, including MAPK-activated protein kinase 5 (MK5). Here we have used enhanced green fluorescent protein fusion proteins to analyze the subcellular localization of MK5. Although this protein is predominantly nuclear in unstimulated cells, MK5 shuttles between the nucleus and the cytoplasm. Furthermore, we have shown that the C-terminal domain of MK5 contains both a functional nuclear localization signal (NLS) and a leucine-rich nuclear export signal (NES), indicating that the subcellular distribution of this kinase reflects the relative activities of these two signals. In support of this, we have shown that stress-induced activation of the p38 MAPK stimulates the chromosomal region maintenance 1 protein-dependent nuclear export of MK5. This is regulated by both binding of p38 MAPK to MK5, which masks the functional NLS, and stress-induced phosphorylation of MK5 by p38 MAPK, which either activates or unmasks the NES. These properties may define the ability of MK5 to differentially phosphorylate both nuclear and cytoplasmic targets or alternatively reflect a mechanism whereby signals initiated by activation of MK5 in the nucleus may be transmitted to the cytoplasm.


Sign in / Sign up

Export Citation Format

Share Document