scholarly journals RCAN1 Reduces FBXW7β Transcription by Inhibiting Calcineurin/NFAT Signaling Pathway

2021 ◽  
Author(s):  
Shuai Wang ◽  
Yu Yang ◽  
Ruying Song ◽  
Yiming Gao ◽  
Yili Wu
Keyword(s):  
Signaling Pathway ◽  
Binding Sites ◽  
Brain Function ◽  
Promoter Activity ◽  
Neuronal Degeneration ◽  
Dependent Manner ◽  
Potential Mechanism ◽  
Aberrant Expression ◽  
Functional Implication ◽  
Vital Factor

Abstract Regulator of calcineurin 1 (RCAN1), a crucial endogenous regulator of calcineurin, is implicated in multiple important physiological and pathological processes. Aberrant expression of RCAN1 is commonly found in brains of patients with Down syndrome (DS) or Alzheimer’s disease (AD), accounting for impaired neurodevelopment in DS and neuronal degeneration in AD, respectively. However, the mechanism of RCAN1 in brain development and neurodegeneration remains unclear. FBXW7 functions as vital factor in neurodevelopment and neurodegeneration via mediating proteasomal degradation of its substrates. Deficiency of FBXW7 contributes to impaired neurodevelopment and accelerating neurodegeneration. Here, we show that increased RCAN1 reduces the level of β isoform of FBXW7 (FBXW7β). RCAN1 inhibits FBXW7β transcription in a calcineurin dependent manner. Potential NFAT binding sites are identified within the promoter of FBXW7β, and NFAT is also demonstrated to activate the promoter activity of FBXW7β. In summary, our work implies that RCAN1 can regulate FBXW7β expression by inhibiting FBXW7β transcription via calcineurin/NFAT signaling pathway. It could provide more understanding on the mechanism of FBXW7 regulation and suggest a potential mechanism on functional implication of RCAN1 with impaired brain function in some neurodevelopmental and neurodegenerative diseases.

scholarly journals Mot3, a Zn Finger Transcription Factor That Modulates Gene Expression and Attenuates Mating Pheromone Signaling in Saccharomyces cerevisiae

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 879-892 ◽  
Author(s):  
Anatoly V Grishin ◽  
Michael Rothenberg ◽  
Maureen A Downs ◽  
Kendall J Blumer
Keyword(s):  
Gene Expression ◽  
Saccharomyces Cerevisiae ◽  
Signaling Pathway ◽  
G Protein ◽  
Binding Sites ◽  
Dependent Manner ◽  
Pheromone Response ◽  
Mating Pheromone ◽  
Pheromone Signaling ◽  
Yeast Genes

Abstract In the yeast Saccharomyces cerevisiae, mating pheromone response is initiated by activation of a G protein- and mitogen-activated protein (MAP) kinase-dependent signaling pathway and attenuated by several mechanisms that promote adaptation or desensitization. To identify genes whose products negatively regulate pheromone signaling, we screened for mutations that suppress the hyperadaptive phenotype of wild-type cells overexpressing signaling-defective G protein β subunits. This identified recessive mutations in MOT3, which encodes a nuclear protein with two Cys2-His2 Zn fingers. MOT3 was found to be a dosage-dependent inhibitor of pheromone response and pheromone-induced gene expression and to require an intact signaling pathway to exert its effects. Several results suggested that Mot3 attenuates expression of pheromone-responsive genes by mechanisms distinct from those used by the negative transcriptional regulators Cdc36, Cdc39, and Mot2. First, a Mot3-lexA fusion functions as a transcriptional activator. Second, Mot3 is a dose-dependent activator of several genes unrelated to pheromone response, including CYC1, SUC2, and LEU2. Third, insertion of consensus Mot3 binding sites (C/A/T)AGG(T/C)A activates a promoter in a MOT3-dependent manner. These findings, and the fact that consensus binding sites are found in the 5′ flanking regions of many yeast genes, suggest that Mot3 is a globally acting transcriptional regulator. We hypothesize that Mot3 regulates expression of factors that attenuate signaling by the pheromone response pathway.

scholarly journals Fibroblast Growth Factors Regulate Prolactin Transcription via an Atypical Rac-Dependent Signaling Pathway

2003 ◽  
Vol 17 (10) ◽  
pp. 1921-1930 ◽  
Author(s):  
Twila A. Jackson ◽  
David M. Koterwas ◽  
Melissa A. Morgan ◽  
Andrew P. Bradford
Keyword(s):  
Gene Expression ◽  
Growth Factors ◽  
Signaling Pathway ◽  
Promoter Activity ◽  
Fibroblast Growth Factors ◽  
Dominant Negative ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Fibroblast Growth ◽  
Prl Gene

Abstract Fibroblast growth factors (FGFs) play a critical role in pituitary development and in pituitary tumor formation and progression. We have previously characterized FGF signal transduction and regulation of the tissue-specific rat prolactin (rPRL) promoter in GH4 pituitary cells. FGF induction of rPRL transcription is independent of Ras, but mediated by a protein kinase C-δ (PKCδ)-dependent activation of MAPK (ERK). Here we demonstrate a functional role for the Rho family monomeric G protein, Rac1, in FGF regulation of PRL gene expression via an atypical signaling pathway. Expression of dominant negative Rac, but not RhoA or Cdc42, selectively inhibited FGF-induced rPRL promoter activity. Moreover, expression of dominant negative Rac also attenuated FGF-2 and FGF-4 stimulation of MAPK (ERK). However, in contrast to other Rac-dependent signaling pathways, FGF activation of rPRL promoter activity was independent of the c-Jun N-terminal kinase (JNK) and phosphoinositide 3-kinase/Akt cascades. FGFs failed to activate JNK1 or JNK2, and expression of dominant negative JNK or Akt constructs did not block FGF-induced PRL transcription. Consistent with the role of PKCδ in FGF regulation of PRL gene expression, activation of the rPRL promoter was blocked by an inhibitor of phospholipase Cγ (PLCγ) activity. FGF treatment also induced rapid tyrosine phosphorylation of PLCγ in a Rac-dependent manner. These results suggest that FGF-2 and FGF-4 activate PRL gene expression via a novel Rac1, PLCγ, PKCδ, and ERK cascade, independent of phosphoinositol-3-kinase and JNK.

scholarly journals Homoharringtonine inhibits fibroblasts proliferation, extracellular matrix production and reduces surgery-induced knee arthrofibrosis via PI3K/AKT/mTOR pathway-mediated apoptosis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yu Sun ◽  
Jihang Dai ◽  
Rui Jiao ◽  
Qing Jiang ◽  
Jingcheng Wang
Keyword(s):  
Extracellular Matrix ◽  
Cell Death ◽  
Signaling Pathway ◽  
Apoptotic Cell ◽  
Dependent Manner ◽  
Potential Mechanism ◽  
Mtor Signaling Pathway ◽  
Extracellular Matrix Production ◽  
Matrix Production

Abstract Background The prevention of surgery-induced intraarticular fibrosis remains a challenge following orthopedic surgery. Homoharringtonine (HHT) has been reported to have positive effects in preventing various kinds of fibrosis. However, little is known regarding its effect as well as the potential mechanism of HHT in preventing surgery-induced intraarticular fibrosis. Methods Various concentrations of HHTs were locally applied in vivo to reduce knee intraarticular fibrosis in rabbits. Histological macroscopic assessments such as hematoxylin and eosin (HE) staining, Masson’s trichrome staining, and Picric-sirius red polarized light were used to evaluate the effect of HHT in reducing intraarticular fibrosis. CCK-8, cell cycle assay, and EdU incorporation assay were used in vitro to detect HHT’s effect on inhibiting fibroblast viability and proliferation. The effect of HHT on fibroblast differentiation, extracellular matrix production, and apoptosis were evaluated by western blot, flow cytometry, immunofluorescent staining, and TUNEL analysis. Moreover, the expressions of PI3K/AKT/mTOR signaling pathway were detected. Results The results demonstrated that HHT could reduce the formation of intraarticular fibrosis. HHT was also found to induce fibroblast apoptotic cell death in a dose- and time-dependent manner in vitro. Moreover, HHT could effectively inhibit the production of the extracellular matrix secreted by fibroblasts and inhibited the expression of p-PI3K, p-AKT, and p-mTOR in a dose-dependent manner. After treating with insulin-like growth factor-1 (IGF-1), an activator of the PI3K/AKT axis, the expressions of pro-apoptosis-related proteins were decreased, and the fibroblast apoptosis rate was also inhibited. Conclusions In conclusion, this study demonstrated that HHT could reduce the formation of intraarticular fibrosis through the inhibition of fibroblast proliferation, extracellular matrix production, and the induction of fibroblast apoptotic cell death. Furthermore, its potential mechanism may be through the suppression of the PI3K/AKT/mTOR signaling pathway.

scholarly journals Dysregulation of microRNA-125b is involved in the pathogenesis of post-operative infection via modulating the STAT3/procalcitonin (PCT) signaling pathway

2021 ◽  
Author(s):  
Li Wang ◽  
Mingzhu Yang ◽  
Xuan Jin
Keyword(s):  
Signaling Pathway ◽  
Binding Sites ◽  
Area Under The Curve ◽  
Predictive Biomarker ◽  
Luciferase Assay ◽  
Dependent Manner ◽  
C Reactive Protein ◽  
Infection Group ◽  
Reactive Protein ◽  
Lps Treatment

IntroductionProcalcitonin (PCT) has been reported to function as a predictive biomarker of post-operative infection. In this study, we aimed to explore the mechanisms underlying the regulation of PCT expression.Material and methods72 children diagnosed with post-operative infection and 58 children without post-operative infection were recruited in this study. Computational analysis, luciferase assay, real-time PCR, Western-blot analysis, and assays of post-operative C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) and PCT were performed to investigate the mechanisms underlying the regulation of PCT expression.ResultsMiR-125b was found to repress STAT3 expression with putative binding sites in 3’UTR of STAT3. The levels of PCT and miR-125b in non-infection group remained stable from day 0 to day 5, while the level of PCT was increased in the infection group along with a decreased level of miR-125b from day 1 to day 5. The post-operative levels of CRP and ESR in both non-infection and infection groups were evidently increased in a time-dependent manner, but the levels of miR-106b and miR-20a in both non-infection and infection groups remained stable. The area under the curve (AUC) values of PCT, CRP, ESR, miR-125b, miR-106b and miR-20a demonstrated that only miR-125b and PCT were involved in infection. Transfection with miR-125b reduced STAT3 expression, while the activation of STAT3 by lipopolysaccharide (LPS) treatment up-regulated PCT production. Finally, miR-125b down-regulated the expression of PCT by targeting STAT3.ConclusionsTaken together, we suggested that miR-125b was involved in the prognosis and diagnosis of poster-operative infection by modulating the signaling pathway of miR-125b/STAT3/PCT.

scholarly journals Heme Oxygenase-1 Gene Activation by the NAD(P)H Oxidase Inhibitor 4-(2-Aminoethyl) Benzenesulfonyl Fluoride via a Protein Kinase B, p38-dependent Signaling Pathway in Monocytes

2005 ◽  
Vol 280 (23) ◽  
pp. 21820-21829 ◽  
Author(s):  
Nastiti Wijayanti ◽  
Thomas Kietzmann ◽  
Stephan Immenschuh
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Signaling Pathway ◽  
Heme Oxygenase ◽  
Promoter Activity ◽  
Protein Kinase B ◽  
Oxidase Inhibitor ◽  
Luciferase Assay ◽  
Heme Oxygenase 1 ◽  
Dependent Manner

Heme oxygenase (HO)-1 is the inducible isoform of the rate-limiting enzyme of heme degradation and modulates the inflammatory immune response. Because HO-1 is up-regulated by NAD(P)H oxidase activators such as lipopolysaccharide and 12-O-tetradecanoylphorbol-13-acetate in monocytic cells, we investigated the gene regulation of HO-1 by the chemical NAD(P)H oxidase inhibitor 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF). Unexpectedly, AEBSF induced endogenous gene expression and promoter activity of HO-1 in cell cultures of human and mouse monocytes. Inhibition of the phosphatidylinositol 3-kinase/protein kinase B (PKB) pathway by pharmacological inhibitors and cotransfection of an expression vector for a dominant negative mutant of PKB reduced the AEBSF-dependent induction of HO-1 gene transcription. Accordingly, overexpressed constitutively active PKB markedly up-regulated HO-1 promoter activity. AEBSF activated the mitogen-activated protein kinases (MAPK) JNK and p38. Inhibition of p38α and p38β, but not that of JNK or p38γ and p38δ, prevented the induction of HO-1 gene expression by AEBSF. p38 was stimulated by AEBSF in a PKB-dependent manner as demonstrated by a luciferase assay with a Gal4-CHOP fusion protein. Finally, AEBSF- and PKB-dependent induction of HO-1 promoter activity was reduced by simultaneous mutation of an E-box motif (–47/–42) and a cAMP response element/AP-1 element (–664/–657) of the proximal HO-1 gene promoter. Overexpression of the basic helix-loop-helix transcription factor USF2 and coactivator p300 enhanced the AEBSF-dependent response of the HO-1 promoter. The data suggest that the transcriptional induction of HO-1 gene expression by AEBSF is mediated via activation of a PKB, p38 MAPK signaling pathway.

scholarly journals Stimulation of Steroid Receptor Coactivator-3 (SRC-3) Gene Overexpression by a Positive Regulatory Loop of E2F1 and SRC-3

2006 ◽  
Vol 20 (12) ◽  
pp. 3105-3119 ◽  
Author(s):  
Paola Mussi ◽  
Chundong Yu ◽  
Bert W. O’Malley ◽  
Jianming Xu
Keyword(s):  
Breast Cancer ◽  
Binding Sites ◽  
Promoter Activity ◽  
Steroid Receptor ◽  
Regulatory Sequence ◽  
Dependent Manner ◽  
Breast Cancers ◽  
Steroid Receptor Coactivator ◽  
Regulatory Loop

Abstract Steroid receptor coactivator 3 (SRC-3, amplified in breast cancer 1, or ACTR) is a transcriptional coactivator for nuclear receptors and certain other transcription factors such as E2F1. SRC-3 is overexpressed in breast cancers, and its overexpression is sufficient to cause mammary carcinomas in vivo. However, the mechanisms controlling endogenous SRC-3 overexpression are unknown. In this study, we identified the first exon and analyzed the 5′ regulatory sequence of the SRC-3 gene. We found three evolutionarily conserved regions (ECRs) in the 5′ SRC-3 regulatory sequence, and ECR2 makes a major contribution to the SRC-3 promoter activity. The ECR2 region (bp −250/+350) contains several specificity protein 1 (Sp1) binding sites and two E2F1 binding sites. We show that E2F1 can significantly activate the ECR2 promoter activity in a dose-dependent manner. Furthermore, overexpression of E2F1 significantly increases the promoter activity of the endogenous SRC-3 gene and boosts SRC-3 expression in vivo. Conversely, knockdown of E2F1 reduces SRC-3 expression. We demonstrate that the mechanism of E2F1 activity on SRC-3 promoter is independent of the E2F binding sites but relies on the Sp1 element located at bp +150/+160. Sp1, E2F1, and SRC-3 are specifically recruited to this Sp1 site and the interaction between E2F1 and Sp1 is essential to modulate SRC-3 expression. Moreover, SRC-3 coactivates E2F1 activity and thereby additively stimulates a further increase in SRC-3 expression in vivo. These results suggest that in cells with hyperactive E2F1, such as the case encountered in breast cancer cells, there is a positive feedback regulatory loop consisting of E2F1 and SRC-3 to maintain high levels of SRC-3 and E2F1 activity, which may partially interpret the oncogenic role of SRC-3 overexpression.

Irisin Ameliorates Hypoxia/Reoxygenation-Induced Inflammation and Apoptosis in PC12 Cells by Inhibiting TLR4/MYD88 Signaling Pathway

2019 ◽  
Vol 17 (3) ◽  
pp. 329-336
Author(s):  
Wang Jinli ◽  
Xu Fenfen ◽  
Zheng Yuan ◽  
Cheng Xu ◽  
Zhang Piaopiao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Signaling Pathway ◽  
Pc12 Cells ◽  
Major Complication ◽  
Lactic Dehydrogenase ◽  
Dependent Manner ◽  
Cerebral Ischemic Stroke ◽  
Cerebral Ischemic ◽  
Myd88 Signaling ◽  
Hypoxia Reoxygenation

Cardiovascular disease including cerebral ischemic stroke is the major complication that increases the morbidity and mortality in patients with diabetes mellitus as much as four times. It has been well established that irisin, with its ability to regulate glucose and lipid homeostasis as well as anti-inflammatory and anti-apoptotic properties, has been widely examined for its therapeutic potentials in managing metabolic disorders. However, the mechanism of irisin in the regulation of cerebral ischemic stroke remains unclear. Using PC12 cells as a model, we have shown that hypoxia/reoxygenation inhibits cell viability and increases lactic dehydrogenase. Irisin, in a dose-dependent manner, reversed these changes. The increase in inflammatory mediators (IL-1β, IL-6, and TNF-α) by hypoxia/reoxygenation was reversed by irisin. Furthermore, the cell apoptosis promoted by hypoxia/reoxygenation was also inhibited by irisin. Irisin suppressed TLR4/MyD88 signaling pathway leading to amelioration of inflammation and apoptosis in PC12 cells. Thus, inhibition of TLR4/MyD88 signaling pathway via irisin could be an important mechanism in the regulation of hypoxia/reoxygenation-induced inflammation and apoptosis in PC12 cells.

Prognostic Role of Hedgehog-GLI1 Signaling Pathway in Aggressive and Metastatic Breast Cancers

2020 ◽  
Vol 21 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Prasuja Rokkam ◽  
Shailender Gugalavath ◽  
Deepak Kakara Gift Kumar ◽  
Rahul Kumar Vempati ◽  
Rama Rao Malla
Keyword(s):  
Breast Cancer ◽  
Signaling Pathway ◽  
Neural Development ◽  
Splice Variants ◽  
Metastatic Breast ◽  
Basic Function ◽  
Breast Cancers ◽  
Breast Cancer Patients ◽  
Aberrant Expression ◽  
Cellular Processes

Glioma-associated oncogene homolog 1 (GLI1) is reported as an amplified gene in human glioblastoma cells. It is a krupple like transcription factor, belonging to the zinc finger family. The basic function of GLI1 is normal neural development at various stages of human. The GLI1 gene was first mapped on the chromosome sub-bands 12q13.3-14.1. Further, single nucleotide polymorphism is mostly observed in translating a region of 5’ and 3’- UTR of GLI1 gene in addition to two post-transcriptional splice variants, GLIΔN and tGLI. Additionally, it also regulates a plethora of gene which mediates crucial cellular processes like proliferation, differentiation, oncogenesis, EMT, and metastasis. It also regulates tumor tolerance, chemoresistance, and radioresistance. Aberrant expression of GLI1 predicts the poor survival of breast cancer patients. GLI1 is an essential mediator of the SHH signaling pathway regulating self-renewal of stem cells, angiogenesis, and expression of FOXS1, CYR61. GLI1 mediated HH pathway can induce apoptosis. Hence, GLI1 can be a future diagnostic, prognostic marker, and as well as a potent target of therapeutics in breast cancer.

Pisosterol Induces G2/M Cell Cycle Arrest and Apoptosis via the ATM/ATR Signaling Pathway in Human Glioma Cells

2020 ◽  
Vol 20 (6) ◽  
pp. 734-750
Author(s):  
Wallax A.S. Ferreira ◽  
Rommel R. Burbano ◽  
Claudia do Ó. Pessoa ◽  
Maria L. Harada ◽  
Bárbara do Nascimento Borges ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Signaling Pathway ◽  
Glioma Cell ◽  
Molecular Mechanisms ◽  
Glioma Cells ◽  
Dependent Manner ◽  
M Cell ◽  
Trypan Blue Exclusion ◽  
Cycle Arrest

Background: Pisosterol, a triterpene derived from Pisolithus tinctorius, exhibits potential antitumor activity in various malignancies. However, the molecular mechanisms that mediate the pisosterol-specific effects on glioma cells remain unknown. Objective: This study aimed to evaluate the antitumoral effects of pisosterol on glioma cell lines. Methods: The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue exclusion assays were used to evaluate the effect of pisosterol on cell proliferation and viability in glioma cells. The effect of pisosterol on the distribution of the cells in the cell cycle was performed by flow cytometry. The expression and methylation pattern of the promoter region of MYC, ATM, BCL2, BMI1, CASP3, CDK1, CDKN1A, CDKN2A, CDKN2B, CHEK1, MDM2, p14ARF and TP53 was analyzed by RT-qPCR, western blotting and bisulfite sequencing PCR (BSP-PCR). Results: Here, it has been reported that pisosterol markedly induced G2/M arrest and apoptosis and decreased the cell viability and proliferation potential of glioma cells in a dose-dependent manner by increasing the expression of ATM, CASP3, CDK1, CDKN1A, CDKN2A, CDKN2B, CHEK1, p14ARF and TP53 and decreasing the expression of MYC, BCL2, BMI1 and MDM2. Pisosterol also triggered both caspase-independent and caspase-dependent apoptotic pathways by regulating the expression of Bcl-2 and activating caspase-3 and p53. Conclusions: It has been, for the first time, confirmed that the ATM/ATR signaling pathway is a critical mechanism for G2/M arrest in pisosterol-induced glioma cell cycle arrest and suggests that this compound might be a promising anticancer candidate for further investigation.

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