scholarly journals Both Hypoxia-Inducible Factor 1 and MAPK Signaling Pathway Attenuate PI3K/AKT via Suppression of Reactive Oxygen Species in Human Pluripotent Stem Cells

Author(s):  
Petr Fojtík ◽  
Deborah Beckerová ◽  
Katerina Holomková ◽  
Martin Šenfluk ◽  
Vladimir Rotrekl

Mild hypoxia (5% O2) as well as FGFR1-induced activation of phosphatidylinositol-4,5-bisphosphate 3-kinase/protein kinase B (PI3K/AKT) and MAPK signaling pathways markedly support pluripotency in human pluripotent stem cells (hPSCs). This study demonstrates that the pluripotency-promoting PI3K/AKT signaling pathway is surprisingly attenuated in mild hypoxia compared to the 21% O2 environment. Hypoxia is known to be associated with lower levels of reactive oxygen species (ROS), which are recognized as intracellular second messengers capable of upregulating the PI3K/AKT signaling pathway. Our data denote that ROS downregulation results in pluripotency upregulation and PI3K/AKT attenuation in a hypoxia-inducible factor 1 (HIF-1)-dependent manner in hPSCs. Using specific MAPK inhibitors, we show that the MAPK pathway also downregulates ROS and therefore attenuates the PI3K/AKT signaling—this represents a novel interaction between these signaling pathways. This inhibition of ROS initiated by MEK1/2–ERK1/2 may serve as a negative feedback loop from the MAPK pathway toward FGFR1 and PI3K/AKT activation. We further describe the molecular mechanism resulting in PI3K/AKT upregulation in hPSCs—ROS inhibit the PI3K's primary antagonist PTEN and upregulate FGFR1 phosphorylation. These novel regulatory circuits utilizing ROS as second messengers may contribute to the development of enhanced cultivation and differentiation protocols for hPSCs. Since the PI3K/AKT pathway often undergoes an oncogenic transformation, our data could also provide new insights into the regulation of cancer stem cell signaling.

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4138
Author(s):  
Yeon-Jin Cho ◽  
Sun-Hye Choi ◽  
Ra-Mi Lee ◽  
Han-Sung Cho ◽  
Hyewhon Rhim ◽  
...  

Gintonin is a kind of ginseng-derived glycolipoprotein that acts as an exogenous LPA receptor ligand. Gintonin has in vitro and in vivo neuroprotective effects; however, little is known about the cellular mechanisms underlying the neuroprotection. In the present study, we aimed to clarify how gintonin attenuates iodoacetic acid (IAA)-induced oxidative stress. The mouse hippocampal cell line HT22 was used. Gintonin treatment significantly attenuated IAA-induced reactive oxygen species (ROS) overproduction, ATP depletion, and cell death. However, treatment with Ki16425, an LPA1/3 receptor antagonist, suppressed the neuroprotective effects of gintonin. Gintonin elicited [Ca2⁺]i transients in HT22 cells. Gintonin-mediated [Ca2⁺]i transients through the LPA1 receptor-PLC-IP3 signaling pathway were coupled to increase both the expression and release of BDNF. The released BDNF activated the TrkB receptor. Induction of TrkB phosphorylation was further linked to Akt activation. Phosphorylated Akt reduced IAA-induced oxidative stress and increased cell survival. Our results indicate that gintonin attenuated IAA-induced oxidative stress in neuronal cells by activating the LPA1 receptor-BDNF-TrkB-Akt signaling pathway. One of the gintonin-mediated neuroprotective effects may be achieved via anti-oxidative stress in nervous systems.


PLoS ONE ◽  
2016 ◽  
Vol 11 (5) ◽  
pp. e0154770 ◽  
Author(s):  
Amir M. Hossini ◽  
Annika S. Quast ◽  
Michael Plötz ◽  
Katharina Grauel ◽  
Tarik Exner ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Min Shao

We aimed to identify risk pathways for postmenopausal osteoporosis (PMOP) via establishing an microRNAs- (miRNA-) regulated pathway network (MRPN). Firstly, we identified differential pathways through calculating gene- and pathway-level statistics based on the accumulated normal samples using the individual pathway aberrance score (iPAS). Significant pathways based on differentially expressed genes (DEGs) using DAVID were extracted, followed by identifying the common pathways between iPAS and DAVID methods. Next, miRNAs prediction was implemented via calculating TargetScore values with precomputed input (log fold change (FC), TargetScan context score (TSCS), and probabilities of conserved targeting (PCT)). An MRPN construction was constructed using the common genes in the common pathways and the predicted miRNAs. Using false discovery rate (FDR) < 0.05, 279 differential pathways were identified. Using the criteria of FDR < 0.05 and log⁡FC≥2, 39 DEGs were retrieved, and these DEGs were enriched in 64 significant pathways identified by DAVID. Overall, 27 pathways were the common ones between two methods. Importantly, MAPK signaling pathway and PI3K-Akt signaling pathway were the first and second significantly enriched ones, respectively. These 27 common pathways separated PMOP from controls with the accuracy of 0.912. MAPK signaling pathway and PI3K/Akt signaling pathway might play crucial roles in PMOP.


2019 ◽  
Author(s):  
Jie Bao ◽  
Zhengyang Zhu ◽  
Xizhao Zhang ◽  
Lin Huang ◽  
Li Xu ◽  
...  

Abstract Background. MiRNAs has become an important regulator in many processes. The purpose of our study is to screen the key serum miRNAs of different syndrome of recurrent aphthous stomatitis (RAS), to find new biomarkers for the diagnosis of RAS and to further explore their role in the pathogenesis of RAS.Method. Serum samples were collected from patients meeting the RAS diagnostic criteria of excess-heat or yin-deficiency syndrome and healthy individuals. Core miRNAs were then identified under miRNA microarray analyses. Target prediction and bioinformatic analyses were carried out and gene-pathway-networks were visualized to better understand the relationship between different genes and pathways.Result. (1) 90 individuals meeting the inclusion criteria were collected in this study, of which 30 were normal control, 30 were patients of excess-heat syndrome and the rest were patients of yin-deficiency syndrome. Among them, 9 miRNAs were screened out in excess-heat syndrome group, with 1 upregulated and 8 downregulated. And four random miRNAs (hsa-miR-20b-5p, hsa-miR-122-5p, hsa-miR-483-5p and hsa-miR-3197) were validated by real-time PCR method. 14 miRNAs were screened out in yin-deficiency syndrome group (7 upregulated and 7 downregulated). And hsa-miR-17-5p, hsa-miR-106-5p and hsa-miR-20b-5p were validated. (2) A total of 4776 target genes were identified for the validated 9 miRNAs in excess-heat syndrome group. These targets were enriched in GO categories including nervous system development, homophilic cell adhesion via plasma membrane adhesion molecules, and calcium ion binding and KEGG pathway such as proteoglycans in cancer, P13K-AKT signaling pathway and Calcium signaling pathway. 10172 target genes were identified for the validated 14 miRNAs in yin-deficiency syndrome group. The enriched GO categories included protein binding, positive regulation of transcription from RNA polymerase II promoter and membrane and enriched KEGG pathway included pathways in cancer, MAPK signaling pathway and Ras signaling pathway .Conclusion. Hsa-miR-20b-5p in patients with RAS could act as the novel biomarker for clinical diagnosis of the disease. It is upregulated in RAS patients of excess-heat syndrome while downregulated in patients of yin-deficiency syndrome. The PI3K-Akt signaling pathway and MAPK signaling pathway and related target genes may provide new insights into the molecular mechanisms of excess-heat syndrome and yin-deficiency syndrome RAS, respectively.


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