Prohepcidin binds to the HAMP promoter and autoregulates its own expression

2013 ◽  
Vol 451 (2) ◽  
pp. 301-311 ◽  
Author(s):  
Edina Pandur ◽  
Katalin Sipos ◽  
László Grama ◽  
Judit Nagy ◽  
Viktor S. Poór ◽  
...  

Hepcidin is the major regulatory peptide hormone of iron metabolism, encoded by the HAMP (hepcidin antimicrobial peptide) gene. Hepcidin is expressed mainly in hepatocytes, but is also found in the blood in both a mature and prohormone form. Although, the function of mature hepcidin and the regulation of the HAMP gene have been extensively studied, the intracellular localization and the fate of prohepcidin remains controversial. In the present study, we propose a novel role for prohepcidin in the regulation of its own transcription. Using indirect immunofluorescence and mCherry tagging, a portion of prohepcidin was detected in the nucleus of hepatocytes. Prohepcidin was found to specifically bind to the STAT3 (signal transducer and activator of transcription 3) site in the promoter of HAMP. Overexpression of prohepcidin in WRL68 cells decreased HAMP promoter activity, whereas decreasing the amount of prohepcidin caused increased promoter activity measured by a luciferase reporter-gene assay. Moreover, overexpression of the known prohepcidin-binding partner, α-1 antitrypsin caused increased HAMP promoter activity, suggesting that only the non-α-1 antitrypsin-bound prohepcidin affects the expression of its own gene. The results of the present study indicate that prohepcidin can bind to and transcriptionally regulate the expression of HAMP, suggesting a novel autoregulatory pathway of hepcidin gene expression in hepatocytes.

2021 ◽  
Vol 20 (9) ◽  
pp. 1845-1853
Author(s):  
Qinfeng Han ◽  
Zhong Xu ◽  
Xiaolei Zhang ◽  
Kun Yang ◽  
Zhifei Sun ◽  
...  

Purpose: To investigate the effect of miR-486 on rats with acute myocardial infarction (AMI), and its mechanism of action.Methods: A rat model of AMI was established. They were randomly divided into 4 groups, namely, sham, model, agomiR-486 and antagomiR-486 groups, respectively. Rats in these different groups were treated with agomiR-21 (5 μL, 40 nmol/mL), antagomiR-21 (5 μL, 40 nmol/mL) or agomiR-NC (5 μL, 40 nmol/mL), respectively. Then, key miRNAs were sorted out using gene-chip assay and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Luciferase reporter gene assay was conducted to determine the interaction between miR-486 and gene of PTEN. After intraperitoneal injection of agomiR-486 and antagomiR-486, hemodynamics was measured to determine the effect of miR-486 on myocardial function of the rats. The effect of miR-486 expression level on the expression of myocardial enzymes in serum, the morphology of myocardial tissues, and the apoptosis of myocardial tissues in rats, were investigated. Additionally, the effect of miR-486 expression level on PTEN/AKT signaling pathway in the rats was determined by Western blotting.Results: The results of gene-chip and qRT-PCR assays revealed that there were 8 differentially expressed genes in rat myocardial tissues in the model group when compared with the sham group. MiR-486 improved the cardiac function of rats and the morphology of myocardial tissues, but reduced AMI-induced apoptosis of myocardial cells and the expression of myocardial enzymes (markers of myocardial injury) in a dose-dependent manner (p < 0.05). The results of luciferase reporter gene assay showed that PTEN was a direct target of miR-486. In rat models of AMI, a raised expression of miR-486 remarkably suppressed the protein expression level of PTEN and up-regulated that of p-AKT/AKT (p < 0.05).Conclusion: MiR-486 protects against AMI in rats probably by targeting PTEN and activating the AKT signaling pathway. The results of the current study may provide new insights for the treatment of AMI.


2021 ◽  
Vol 11 (6) ◽  
pp. 1066-1072
Author(s):  
Bin Guang ◽  
Xiaoqin Liu ◽  
Tingchen Liang

This study was established to determine the effect of miRNA-223-3p on the proliferation and apoptosis of hypoxia/reoxygenation-applied H9c2 cardiomyocytes and the associated mechanisms. A hypoxia/reoxygenation (H/R) model was established, with normal cells also used as a control. miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p plasmids were transfected into normally cultured cardiomyocytes, defined as the miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p groups. In addition, miRNA-223-3p was co-transfected into normally cultured cardiomyocytes with pcDNA3.1 and pcDNA3.1-STIM1 plasmids, followed by treatment with H/R for cells in the miR-NC and miR-223-3p groups, defined as the H/R+miRNA-NC, H/R+miRNA-223-3p, H/R+miRNA-223-3p+pcDNA3.1, and H/R+miRNA-223-3p+pcDNA3.1-STIM1 groups. A liposome method was adopted for assessing transfection. qRT-PCR was used to detect miRNA-223-3p expression, while western blotting was used to detect protein expression. MTT assay was used to detect cell viability, flow cytometry to detect apoptosis, and dual luciferase reporter gene assay to detect fluorescence activity. After H/R treatment, miR-223-3p, cyclin D1, and Bcl-2 expression of cardiomyocytes decreased, p21 and Bax expression significantly increased, cell activity decreased, and the apoptosis rate increased. miRNA-223-3p achieved the targeted regulation of STIM1 expression. miRNA-223-3p overexpression promoted the H/R-induced cardiomyocyte proliferation and inhibited cardiomyocyte apoptosis. STIM1 overexpression reversed the proliferation-promoting and apoptosis-inhibiting effects of miRNA-223-3p on cardiomyocytes treated with H/R. The findings show that miRNA-223-3p overexpression promotes H/R-induced cell proliferation, inhibits apoptosis, and protects H/R-induced cardiomyocytes from injury, via a mechanism probably associated with STIM1 expression. miRNA-223-3p thus provides a new target for treating cardiomyocyte injury.


Author(s):  
Chijiang Gu ◽  
Mingyuan Zhang ◽  
Weiliang Sun ◽  
Changzheng Dong

Colorectal cancer (CRC) is a common clinical cancer that remains incurable in most cases. miRNAs are reported to play a part in the development of various tumors. In the present study, we found that miR-324-5p was downregulated in CRC cells, while ELAV (embryonic lethal, abnormal vision, Drosophila)-like protein 1 (ELAVL1) showed a higher expression. miR-324-5p transfection significantly inhibited the proliferation as well as invasion in both SW620 and SW480 cells. miR-324-5p mimic transfection markedly decreased the expression of ELAVL1. Luciferase reporter gene assay confirmed that ELAVL1 is a direct target of miR-324-5p. Furthermore, cancer invasion factors uPA, uPAR, and MMP-9 were found to drop significantly in miR-324-5p-transfected groups. To conclude, our findings indicate that miR-324-5p may play a suppressive role in colorectal cell viability and invasion, at least in part, through directly targeting ELAVL1. Therefore, miR-234-5p might function as a promising candidate for CRC treatment and deserves deeper research.


Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2585 ◽  
Author(s):  
Lehao Wu ◽  
Weiyue Zhang ◽  
Xin Qiu ◽  
Chaoran Wang ◽  
Yanfang Liu ◽  
...  

Corydalis yanhusuo W. T. Wang (C. yanhusuo) has been traditionally used for drug addiction and pain relief in China. In our previous study, we showed that the extract of C. yanhusuo blocks dopamine receptors, demonstrating that its pharmacological activities are mostly due to the antagonistic effects of some of its components at dopamine receptors. As part of our ongoing project on C. yanhusuo, the aim of the present study is to establish a high-throughput and low-cost screening assay system and test the abilities of the isolated alkaloids from C. yanhusuo to inhibit dopamine-induced dopamine D1 receptor activity. By using our established cyclic adenosine monophosphate (cAMP)-response element (CRE)-luciferase reporter gene assay system, we identified eight alkaloids from C. yanhusuo with D1 receptor antagonistic activities. We next validated the activities of these compounds using fluorometric imaging plate reader (FLIPR) assay by measuring the intracellular Ca2+ change. Six out of eight compounds, including tetrahydropalmatine, corydaline, 13-methyldehydrocorydalmine, dehydrocorybubine, dehydrocorydaline, and columbamine, can be confirmed for their inhibitory activities. The dopamine-receptor-antagonistic effects of four compounds, including 13-methyldehydrocorydalmine, dehydrocorydaline, columbamine, and corydaline, are reported for the first time. The present study provides an important pharmacological basis to support the traditional use of C. yanhusuo in China.


2017 ◽  
Vol 95 (5) ◽  
pp. 578-584 ◽  
Author(s):  
Lei Yan ◽  
Kerui Cai ◽  
Jun Liang ◽  
Haifeng Liu ◽  
Yang Liu ◽  
...  

We investigated the how miR-572 regulates PPP2R2C, and studied the effects of miR-572 and PPP2R2C on proliferation and migration as well as invasion of nasopharyngeal carcinoma (NPC) cells. NPC tissues and normal tissues were collected, and the expressions of miR-572 and PPP2R2C were detected by real-time PCR. Western blot was applied to detect the expression of PPP2R2C protein. The target relationship between miR-572 and PPP2R2C was confirmed by dual luciferase reporter gene assay. MTT assay and flow cytometry were applied to investigate the viability and apoptosis levels of NPC cells. Transwell as well as wound healing assays were used, respectively, to detect the invasiveness and migration of NPC cells. MiR-572 was highly expressed in NPC tissues as well as NPC cells, and there was lower expression of PPP2R2C in NPC tissues compared with normal samples. MiR-572 could bind to the 3′ UTR of PPP2R2C and decrease its expression. Over-expressed miR-572 and decreased PPP2R2C expression could both inhibit proliferation and invasion and induce apoptosis of NPC cells. Thus, miR-572 promotes the proliferation and invasion of NPC by directly down-regulating PPP2R2C.


2020 ◽  
Author(s):  
Zhi-Li Hu ◽  
Yang-zhi Hu ◽  
Qing Li ◽  
Tian-you Liao ◽  
Hai-ping Jiang

Abstract Background: It has been reported that reduction of miR-126 can promote the progression of gastric cancer (GC). However, the regulation of miR-126 in GC is still unclear. This study aims to explore the correlation between lncRNA MALAT1 and miR-126 in gastric cancer and disclose the underlying mechanisms.Methods: We analyzed the correlation of MALAT1 levels and clinical features by analysis of bioinformatic data and human samples. Then we down-regulate the expression of MALAT1 in AGS cells and examined the characteristics of cell proliferation, cycle, apoptosis, migration, invasion, and the effect on miR-126 as well as VEGFA and signaling pathway. In addition, we demonstrated the role of MALAT1/miR-126 axis in GC with dual-luciferase reporter gene assay and treatment of miR-126 inhibitor.Results: The expression of MALAT1 was higher in cancer tissues than para-cancer tissues. In addition, high MALAT1 level suggested greater malignancy and poorer prognosis. Down-regulating the expression of MALAT1 in AGS cells inhibited cell proliferation, migration, and invasion by targeting VEGFA, which is consistent with up-regulation of miR-126. According to dual-luciferase reporter gene assay and treatment of miR-126 inhibitor, we demonstrated that MALAT1 down-regulated miR-126 in GC, which leads to the up-regulation of VEGFA and activation of mTOR signaling pathway.Conclusions: MALAT1/miR-126 axis promotes growth and metastasis of gastric cancer through regulation of VEGFA via mTOR signaling pathway.Fund This article is supported by Science and Technology Funding Project of Hunan Province, China (No.2017SK4010)


2020 ◽  
Author(s):  
Juan Tong ◽  
Huilan Liu ◽  
Changcheng Zheng ◽  
Xiaoyu Zhu ◽  
Xiang Wan ◽  
...  

Abstract Background: Accumulating circular RNAs (circRNAs) are reported to be abnormally expressed in diverse cancers, hematologic malignancies included. This study aimed to investigate the biological function and underlying mechanisms of circ_0000005 in acute myeloid leukemia (AML).Materials and methods: Bone marrow samples were enrolled from AML patients with normal samples as controls. Circ_0000005, miR-139-5p and tetraspanin 3 (Tspan3) were detected by qRT-PCR and Western blot, respectively. AML cell lines (KG1 and HL60) were used as cell models. CCK-8, Transwell and flow cytometry assays were adopted to study the biological functions of circ_0000005 on AML cells in vitro. The interrelation between circ_0000005 and miR-139-5p was detected by bioinformatics, qRT-PCR, luciferase reporter gene assay, RNA pull-down assay, and RNA-binding protein immunoprecipitation (RIP) assays. Ultimately, Western blot, qRT-PCR, luciferase reporter gene assay were adopted to corroborate the interrelation between miR-139-5p and its target Tspan3. Results: Circ_0000005 was demonstrably elevated in both AML clinical samples and cell lines. Circ_0000005 overexpression promoted the viability, migration and invasion of AML cells, and repressed the apoptosis of AML cells, while silencing circ_0000005 showed opposite biological effects. Circ_0000005 interacted with miR-139-5p and repressed its expression, and Tspan3 was proved to be negatively regulated by miR-139-5p. Circ_0000005 could promote the expression of Tspan3 via repressing miR-139-5p, and the oncogenic functions of circ_0000005 were dependent on its regulatory function on miR-139-5p/Tspan3 axis.Conclusion: Circ_0000005 facilitates the malignant phenotypes of AML cells via miR-139-5p/Tspan3 axis. Circ_0000005 may serve as a potential therapeutic target in AML.


2021 ◽  
Author(s):  
Shuai zhou ◽  
Kang Lin Qu ◽  
JinAng Li ◽  
Shilei Chen ◽  
Yi Gang Zhang ◽  
...  

Abstract Background: Cholangiocarcinoma (CCA) is one of the deadliest cancers of the digestive tract. The prognosis of CCA is poor and the 5-year survival rate is low. Bioinformatic analysis showed that early mitotic inhibitor 2 (EMI2) was overexpressed in CCA but the underlying mechanism is not known.Methods: The data on bile duct carcinoma from TCGA and GEO databases were used to detect the expression of EMI2. The transcription factors of EMI2 were predicted using JASPAR and PROMO databases. Among the predicted transcription factors, YY1 has been rarely reported in cholangiocarcinoma, and was verified using the luciferase reporter gene assay. RT-PCR was performed to predict the downstream pathway of EMI2, and PI3K/Akt was suspected to be associated with it. Subsequently, in vivo and in vitro experiments were conducted to verify the effects of silencing and overexpressing EMI2 and YY1 on the proliferation, invasion, and metastasis of the bile duct cancer cells.Results: EMI2 was highly expressed in CCA. Silencing EMI2 inhibited the proliferation, invasion, and migration of CCA cells, arrested cell cycle in the G1 phase, and inhibition of apoptosis. The luciferase reporter gene assay showed that YY1 bound to the promoter region of EMI2, and after silencing YY1, the expression of EMI2 decreased and the progression of CCA was inhibited. Moreover, key proteins in the PI3K/Akt signaling pathway decreased after silencing EMI2.Conclusion: EMI2 may be one of the direct targets of YY1 and promotes the progression of CCA through the PI3K/Akt signaling pathway.


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