Validation of microRNA Target Genes Using Luciferase Reporter assay and Western Blot Analysis

2022 ◽  
pp. 27-38
Author(s):  
Pooja Panwalkar ◽  
Atul Khire ◽  
Neelam Shirsat
Keyword(s):  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Target Genes ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Microrna Target

scholarly journals MicroRNA-34a Attenuates Paclitaxel Resistance in Prostate Cancer Cells via Direct Suppression of JAG1/Notch1 Axis

2018 ◽  
Vol 50 (1) ◽  
pp. 261-276 ◽  
Author(s):  
Xiaobing Liu ◽  
Xing Luo ◽  
Yuqi Wu ◽  
Ding Xia ◽  
Wei Chen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Tumor Growth ◽  
Western Blot ◽  
Target Genes ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Qrt Pcr

Background/Aims: Treatment options for metastatic castrate-resistant prostate cancer (mCRPC) are limited and typically centered on paclitaxel-based chemotherapy. In this study, we aimed to evaluate whether miR-34a attenuates chemoresistance to paclitaxel by regulating target genes associated with drug resistance. Methods: We used data from The Cancer Genome Atlas to compare miR-34a expression levels in prostate cancer (PC) tissues with normal prostate tissues. The effects of miR-34a inhibition and overexpression on PC proliferation were evaluated in vitro via Cell Counting Kit-8 (CCK-8) proliferation, colony formation, apoptosis, and cell-cycle assays. A luciferase reporter assay was employed to identify the interactions between miR-34a and specific target genes. To determine the effects of up-regulation of miR-34a on tumor growth and chemo-resistance in vivo, we injected PC cells overexpressing miR-34a into nude mice subcutaneously and evaluated the rate of tumor growth during paclitaxel treatment. We examined changes in the expression levels of miR-34a target genes JAG1 and Notch1 and their downstream genes via miR-34a transfection by quantitative reverse transcription PCR (qRT-PCR) and western blot assay. Results: miR-34a served as an independent predictor of reduced patient survival. MiR-34a was down-regulated in PC-3PR cells compared with PC-3 cells. The CCK-8 assay showed that miR-34a overexpression resulted in increased sensitivity to paclitaxel while miR-34a down-regulation resulted in chemoresistance to paclitaxel in vitro. A study of gain and loss in a series of functional assays revealed that PC cells expressing miR-34a were chemosensitive. Furthermore, the overexpression of miR-34a increased the sensitivity of PC-3PR cells to chemotherapy in vivo. The luciferase reporter assay confirmed that JAG1 and Notch1 were directly targeted by miR-34a. Interestingly, western blot analysis and qRT-PCR confirmed that miR-34a inhibited the Notch1 signaling pathway. We found that miR-34a increased the chemosensitivity of PC-3PR cells by directly repressing the TCF1/ LEF1 axis. Conclusion: Our results showed that miR-34a is involved in the development of chemosensitivity to paclitaxel. By regulating the JAG1/Notch1 axis, miR-34a or its target genes JAG1 or Notch1 might serve as potential predictive biomarkers of response to paclitaxel-based chemotherapy and/or therapeutic targets that will help to overcome chemoresistance at the mCRPC stage.

scholarly journals ADSC Exosomes Mediate lncRNA-MIAT Alleviation of Endometrial Fibrosis by Regulating miR-150-5p

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaowen Shao ◽  
Jinlong Qin ◽  
Chendong Wan ◽  
Jiajing Cheng ◽  
Lian Wang ◽  
...  
Keyword(s):  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Target Genes ◽  
Expression Level ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Injury Model ◽  
Gene Assay ◽  
Tgf Β1

BackgroundSecondary infertility remains a major complication of endometrial fibrosis in women. The use of exosomes from adipose-derived mesenchymal stem cells (ADSCs) has shown promising results for the treatment of endometrial fibrosis. However, the mechanisms of action of ADSC-exosome (ADSC-Exo) therapy remain unclear.Materials and MethodsAn endometrial fibrosis model was established in mice treated with alcohol and endometrial epithelial cells (ESCs) treated with TGF-β1. ADSCs were isolated from Sprague Dawley (SD) rats, and exosomes were isolated from ADSCs using ExoQuick reagent. Exosomes were identified by transmission electron microscopy (TEM), NanoSight, and Western blot analysis. The expression level of lncRNA-MIAT was detected by qPCR analysis. Western blot analysis was carried out to determine the protein levels of fibrosis markers (TGFβR1, α-SMA, and CK19). A dual-luciferase reporter gene assay was used to verify the relationship between target genes. The endometrial tissues of the endometrial fibrosis model were stained with HE and Masson’s trichrome.ResultsADSCs and ADSC-Exos were successfully isolated, and the expression level of lncRNA-MIAT was significantly down-regulated in endometrial tissue and the TGF-β1-induced ESC injury model, whereas ADSC-Exos increased the expression of lncRNA-MIAT in the TGF-β1-induced ESC model. Functionally, ADSC-Exo treatment repressed endometrial fibrosis in vivo and in vitro by decreasing the expression of hepatic fibrosis markers (α-SMA and TGFβR1) and increasing the expression of CK19. Moreover, miR-150-5p expression was repressed by lncRNA-MIAT in the TGF-β1-induced ESC injury model. The miR-150-5p mimic promoted TGF-β1-induced ESC fibrosis.ConclusionADSC-Exos mediate lncRNA-MIAT alleviation of endometrial fibrosis by regulating miR-150-5p, which suggests that lncRNA-MIAT from ADSC-Exos may be a viable treatment for endometrial fibrosis.

scholarly journals MicroRNA-326-5p enhances therapeutic potential of endothelial progenitor cells for myocardial infarction

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiaoting Li ◽  
Xiang Xue ◽  
Yuejun Sun ◽  
Lei Chen ◽  
Ting Zhao ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Western Blot ◽  
Progenitor Cells ◽  
Endothelial Progenitor Cells ◽  
Tube Formation ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay

Abstract Background Our study sought to investigate the therapeutic effects and mechanisms of miR-326-5p-overexpressing endothelial progenitor cells (EPCs) on acute myocardial infarction (AMI). Methods Mouse EPCs were isolated, purified, and identified by flow cytometry and uptake of DiI-ac-LDL. The target gene of miR-326-5p was predicted using target prediction algorithms and verified by dual-luciferase reporter assay, RT-qPCR, and Western blot. After EPCs were transfected with the agomir or antagomir of miR-326-5p, tube formation assay and Matrigel plug angiogenesis assay were conducted in four groups (NC, miR-326-5p agomir, miR-326-5p antagomir, and miR-326-5p agomir+Wnt1 agonist). In addition, a mouse model of MI was established and treated with the injection of miR-326-5p-EPCs, miR-326-5p-EPCs+ Wnt1 agonist, EPCs-NC, or PBS/control into the peri-infarcted myocardium. Subsequently, cardiac function was monitored by echocardiography at 7 and 28 days postoperatively. Finally, the infarcted hearts were collected at 28 days, and the size of myocardial infarction was measured by Masson’s trichrome staining and the neovascularization in the peri-infarcted area was examined through immunofluorescence staining. Results Luciferase reporter assay indicated that Wnt1 was a direct target of miR-326-5p. Using RT-qPCR and Western blot analysis, we further demonstrated that the expression level of Wnt1 was negatively correlated with miR-326-5p expression in EPCs. Both in vitro study of tube formation assay and in vivo investigation of subcutaneous Matrigel plug assay revealed that the miR-326-5p agomir could significantly enhance the angiogenic capacity of EPCs, and this effect was partially inhibited by Wnt1 agonist. Meanwhile, miR-326-5p antagomir could obviously reduce the the angiogenic capacity of EPCs in vivo compared with that in the NC group. Moreover, the transplantation of miR-326-5p-overexpressing EPCs in the ischemic hearts of mice significantly enhanced the angiogenesis in the peri-infarcted zone and improved the cardiac function. However, the enhanced capacity of angiogenesis of miR-326-5p-overexpressing EPCs was remarkably neutralized by Wnt1 agonist, accompanied by the decreased improvement in cardiac function. Conclusion miR-326-5p significantly enhanced the angiogenic capacity of EPCs. Transplantation of miR-326-5p-overexpressing EPCs improved cardiac function for AMI therapy, which can be a novel strategy for enhancing therapeutic angiogenesis in ischemic heart diseases.

scholarly journals Knockdown of LincRNA PADNA Promotes Bupivacaine-Induced Neurotoxicity by miR-194/FBXW7 Axis

2020 ◽  
Author(s):  
Fan Yuning ◽  
Chen Liang ◽  
Wang Tenghuan ◽  
Nan Zhenhua ◽  
Shengkai Gong
Keyword(s):  
Functional Analysis ◽  
Western Blot ◽  
Cell Viability ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Drg Neurons ◽  
Dual Luciferase Reporter Assay

Abstract The aim of the study was to explore the function and mechanism of lincRNA PADNA in bupivacaine-induced neurotoxicity. Mouse DRG neurons were cultured in vitro and treated with bupivacaine to establish the neurotoxicity model. Caspase3 activity, cell viability, tunel assay were analyzed to assess the role of lincRNA PADNA. Dual-luciferase reporter assay was used to determine the binding target of lincRNA PANDA. The expression of lincRNA PADNA was significantly increased with the increasing concentration of bupivacaine. Functional analysis revealed that knockdown of lincRNA PADNA accelerated the caspase3 activity and inhibited the cell viability. Western blot showed that knockdown of lincRNA PADNA promoted the occurrence of cleaved-caspase3. We also proved that lincRNA PADNA may bind with miR-194. Overexpression of miR-194 could rescued the function of lincRNA PADNA, suggesting that lincRNA PADNA may sponge miR-194. In addition, we provided new evidences that lincRNA PADNA/miR-194/FBXW7 axis play an important role in the neurotoxicity process. We performed comprehensive experiments to verify the function and mechanism of lincRNA PADNA in bupivacaine-induced neurotoxicity. Our study provided new evidences and clues for prevention of neurotoxicity.

Long non-coding RNA LINC01194 promotes the inflammatory response and apoptosis of LPS-treated MLE 12 cells through the miR-203a-3p /MIP-2 axis

2021 ◽  
Author(s):  
Yuyao Shen ◽  
Senwei Zhao ◽  
Minglei Hua
Keyword(s):  
Inflammatory Response ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Luciferase Reporter ◽  
Mouse Lung ◽  
Elisa Assay ◽  
Non Coding Rna ◽  
Potential Biomarker ◽  
Long Non Coding Rna

Acute lung injury (ALI) induced by bacteria LPS is characterized by the upregulation of the apoptosis rate of tissue cells and aggravation of inflammatory response. Although many studies have focused on the pathogenesis of this disease, its mechanism remains unknown. This study examined the regulatory role of long non-coding RNA (lncRNA) LINC01194 in the progression of ALI through various bioinformatics analyses and experimental work, including ELISA assay, dual-luciferase reporter assay, biotinylated RNA pull-down assay, and western blot analysis. The result showed that the LINC01194 was overexpressed in the ALI-induced mice model. We observed a significant upregulation of LINC01194 in LPS-treated Mouse lung epithelial type II cells (MLE-12 cells) after 24 hrs of induction. Bioinformatics analysis, Elisa assay, qRT-PCR analysis, Biotinylated RNA pull-down assay, apoptosis test, and western blot analysis demonstrated that the LINC01194 could act as a miR-203a-3p sponge to activate the inflammatory response in LPS-induced ALI model through post-transcriptional upregulation of MIP-2. We showed that LINC01194 regulates the inflammatory response and apoptosis of LPS-induced mice and MLE-12 cells via the miR-203a-3p/MIP-2 axis. LINC01194 could be a potential biomarker for early diagnosis and the treatment of ALI.

The CALM/AF10 Interactor CATS Is a Substrate of KIS, a Positive Regulator of Cell Cycle Progression in Leukemia Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2549-2549
Author(s):  
Leticia Fröhlich Archangelo ◽  
Fabíola Traina ◽  
Philipp A Greif ◽  
Alexandre Maucuer ◽  
Valérie Manceau ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Western Blot ◽  
Cell Lines ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Cell Cycle Progression ◽  
Phosphorylation Site ◽  
Luciferase Reporter ◽  
Wild Type ◽  
Cycle Progression

Abstract Abstract 2549 The CATS protein (also known as FAM64A and RCS1) was first identified as a novel CALM (PICALM) interactor that interacts with and influences the subcellular localization of CALM/AF10, a leukemic fusion protein found in acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL) and in malignant lymphoma. CATS is highly expressed in leukemia, lymphoma and tumor cell lines but not in non-proliferating T-cells or in peripheral blood lymphocytes (PBLs). The protein levels of CATS are cell cycle-dependent, induced by mitogens (e.g. PHA) and correlate with the proliferative state of the cell. Thus, CATS is as a marker for proliferation. Using CATS as a bait in a yeast two-hybrid screen we identified the Kinase Interacting Stathmin (KIS or UHMK1) as a CATS interacting partner. KIS is a serine/threonine kinase that positively regulates cell cycle progression through phosphorylation of p27KIP in leukemia cell lines. The interaction between CATS and KIS was confirmed by GST pull-down, and co-immunopreciptation. KIS interaction region was mapped to CATS N-terminal portion. Searching through the phosphorylation site databases PhosphoSitePlus™ (http://www.phosphosite.org) and Phosida (http://www.phosida.com/) we identified 9 residues within CATS shown to be subject of post-translational modification. Phosphorylation assay with recombinant KIS demonstrated that this kinase efficiently phosphorylated full length CATS and its N-terminal part, but not the C-terminal of the protein. To map the KIS phosphorylation site of CATS, peptides comprising all known phospho-sites of CATS N-terminal (S16, S129, S131, T133 and S135) and mutations of the putative KIS target motif (S129 and S131) were tested for KIS phosphorylation. Thereby, we identified CATS S131 as the unique target site for KIS phosphorylation. Western blot analysis of U2OS cells, which had undergone cell cycle synchronization by a double thymidine block, revealed that KIS fluctuated throughout the cell cycle and counteracted CATS levels. Furthermore, we analyzed KIS protein expression on bone marrow mononuclear cells (MNCs) of MDS and AML patients. We studied 5 healthy donors, 13 MDS patients (7 low-risk [RA/RARS] and 6 high-risk [RAEB/RAEBt] according to FAB classification) and 10 AML patients (7 de novo and 3 secondary). Western blot analysis revealed elevated levels of KIS in MDS and AML compared to the control samples. We used a reporter gene assay in order to determine the influence of KIS on the CATS-mediated transcriptional repression and to elucidate the role of KIS-dependent phosphorylation of CATS at serine 131 in this context. Coexpression of GAL4-DBD-CATS and KIS enhanced the inhibitory function of CATS on transactivation of the GAL4-tk-luciferase reporter. This effect of KIS was observed for both CATS wild type and CATS phospho-defective mutant (CATS S131A) but not when the kinase dead mutant KISK54R was used. Moreover, CATS phosphomimetic clone (CATSS131D) exerted the same transcriptional activity as the CATS wild type. These results demonstrate that KIS enhances the transcriptional repressor activity of CATS, and this effect is independent of CATS phosphorylation at S131 but dependent on the kinase activity of KIS. Finally, we investigated whether CATS would affect the CALM/AF10 function as an aberrant transcription factor. Coexpression of constant amounts of GAL4-DBD-CALM/AF10 and increasing amounts of CATS lead to reduced transactivation capacity of CALM/AF10 in a dose dependent manner. Our results show that CATS not only interacts with but is also a substrate for KIS, suggesting that CATS function might be modulated through phosphorylation events. The identification of the CATS-KIS interaction further supports the hypothesis that CATS plays an important role in the control of cell proliferation. Moreover the elevated levels of KIS in hematological malignances suggest that KIS could regulate CATS activity and/or function in highly proliferating leukemic cells. Thus our results indicate that CATS function might be important to understand the malignant transformation mediated by CALM/AF10. Disclosures: No relevant conflicts of interest to declare.

scholarly journals MALAT1 Modulates TGF-β1-Induced Endothelial-to-Mesenchymal Transition through Downregulation of miR-145

2017 ◽  
Vol 42 (1) ◽  
pp. 357-372 ◽  
Author(s):  
Yin Xiang ◽  
Yachen Zhang ◽  
Yong Tang ◽  
Qianhui Li
Keyword(s):  
Target Genes ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Neointimal Hyperplasia ◽  
Luciferase Reporter Assay ◽  
Luciferase Reporter ◽  
Reporter Assay ◽  
Mesenchymal Transition ◽  
Endothelial To Mesenchymal Transition ◽  
Tgf Β1

Background/Aims: Endothelial-to-mesenchymal transition (EndMT) plays significant roles under various pathological conditions including cardiovascular diseases, fibrosis, and cancer. EndMT of endothelial progenitor cells (EPCs) contributes to neointimal hyperplasia following cell therapy Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) that promotes metastasis and cancer. MicroRNA-145 (miR-145) is a tumor suppressor that has been reported to inhibit SMAD3-mediated epithelial-to-mesenchymal transition (EMT) of cancer cells. In the present study, we investigated the role of MALAT1 and miR-145 in EndMT of human circulating EPCs induced by transforming growth factor beta1 (TGF-β1). Methods: Human circulating EPCs were isolated and characterized by fluorescence-activated cell sorting (FACS). Expression levels of EndMT markers were assessed by qRT-PCR and western blotting. Alpha-smooth muscle actin (α-SMA) expression was measured by cell immunofluorescence staining. The regulatory relationship between MALAT1 and miR-145 and its target genes, TGFBR2 (TGFβ receptortype II) and SMAD3 (mothers against decapentaplegic homolog 3) was analyzed using the luciferase reporter assay. Results: We found that EndMT of EPCs induced by TGF-β1 is accompanied by increased MALAT1 expression and decreased miR-145 expression, and MALAT1 and miR-145 directly bind and reciprocally repress each other in these cells. Dual-Luciferase Reporter assay indicated that miR-145 inhibits TGF-β1-induced EndMT by directly targeting TGFBR2 and SMAD3. Conclusions: MALAT1 modulates TGF-β1-induced EndMT of EPCs through regulation of TGFBR2 and SMAD3 via miR-145. Thus, the MALAT1-miR-145-TGFBR2/SMAD3 signaling pathway plays a key role in TGF-β1-induced EndMT.

SIRT1-mediated deacetylation of NF-κB inhibits the MLCK/MLC2 pathway and the expression of ET-1 thus alleviating the development of coronary artery spasm

2020 ◽  
Author(s):  
Bo-Wen Wu ◽  
Mi-Shan Wu ◽  
Yu Liu ◽  
Meng Lu ◽  
Jin-Dong Guo ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Western Blot ◽  
Light Chain ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Myosin Light Chain ◽  
Coronary Artery Spasm ◽  
Luciferase Reporter ◽  
Sirt1 Expression

Coronary artery spasm (CAS) is an intense vasoconstriction of coronary arteries that cause total or subtotal vessel occlusion. The cardioprotective effect of sirtuin-1 (SIRT1) has been extensively highlighted in coronary artery diseases. The aims within this study include the investigation of the molecular mechanism by which SIRT1 alleviates CAS. SIRT1 expression was first determined by RT-qPCR and Western blot analysis in an endothelin-1 (ET-1)-induced rat CAS model. Interaction among SIRT1, nuclear factor-kappaB (NF-κB), myosin light chain kinase/myosin light chain-2 (MLCK/MLC2), and ET-1 was analyzed using luciferase reporter assay, RT-qPCR and Western blot analysis. After ectopic expression and depletion experiments in vascular smooth muscle cells (VSMCs), contraction and proliferation VSMCs, and expression of contraction-related proteins (α-SMA, calponin, and SM22α) were measured by collagen gel contraction, EdU assay, RT-qPCR and Western blot analysis. The obtained results showed that SIRT1 expression was reduced in rat CAS models. However, overexpression of SIRT1 inhibited the contraction and proliferation of VSMCs in vitro. Mechanistic investigation indicated that SIRT1 inhibited NF-κB expression through deacetylation. Moreover, NF-κB could activate the MLCK/MLC2 pathway and up-regulate ET-1 expression by binding to their promoter regions, thus inducing VSMC contraction and proliferation in vitro. In vivo experimental results also revealed that SIRT1 alleviated CAS through regulation of the NF-κB/MLCK/MLC2/ET-1 signaling axis. Collectively, our data suggested that SIRT1 could mediate the deacetylation of NF-κB, disrupt the MLCK/MLC2 pathway and inhibit the expression of ET-1 to relieve CAS, providing a theoretical basis for the prospect of CAS treatment and prevention.

scholarly journals MiR-221/222 Promote Dexamethasone Resistance of Multiple Myeloma through Inhibition of Autophagy By Targeting ATG12

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 4469-4469
Author(s):  
Jian Xu ◽  
Yan Su ◽  
Aoshuang Xu ◽  
Fengjuan Fan ◽  
Haifan Huang ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Death ◽  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Conflicts Of Interest ◽  
Combined Treatment ◽  
Luciferase Reporter ◽  
Pcr Analysis ◽  
Expression Levels

Abstract Dexamethasone (Dex) is the most widely used chemotherapeutic drug in the treatment of multiple myeloma (MM). Inherent or acquired resistance to Dex is broadly associated with poor prognosis in MM. Many microRNAs are aberrantly expressed in MM, including miR-221/222, which have been reported to act as oncogenes in many cancer types. Recently, accumulating evidence has shown that miR-221/222 are involved in the development of chemoresistance in a variety of cancers. However, there is still a lack of valuable data regarding the role of miR-221/222 in the chemoresistance of MM. Here, we first evaluated the expression levels of miR-221/222 in plasma cells (PCs) from MM patients by qRT-PCR analysis. The results showed that miR-221/222 were markedly upregulated in PCs from newly diagnosed MM patients compared to healthy donors, and they were further upregulated in PCs from patients with relapsed MM. In addition, we found that the expression levels of miR-221/222 were inversely correlated with Dex-sensitivity of human MM cell lines (HMCLs). Importantly, enforced expression of miR-221/222 dramatically reduced the sensitivity of Dex-sensitive HMCLs to Dex, while inhibition of miR-221/222 re-sensitized Dex-resistant HMCLs to Dex. Previous studies have shown that Dex-induced cell death in lymphoid leukemia is mediated through initiation of autophagy. To study whether autophagy was involved in Dex-induced cell death in MM cells, HMCLs were exposed to Dex, and then autophagy in these cells was evaluated by the transmission electron microscopy and western blot analysis. The results showed that Dex induced the occurrence of autophagy in Dex-sensitive HMCLs, but not in Dex-resistant HMCLs. Moreover, pharmacological inhibitors of autophagy could significantly reduce Dex-induced cell death in Dex-sensitive HMCLs. These results reveal that autophagy is critical for the induction of cell death following Dex treatment in MM. MicroRNAs have been reported to play an important role in regulating autophagy. We therefore examined whether miR-221/222 can regulate autophagy in MM cells. Low miR-221/222 expressing MM.1S (Dex-sensitive) or high miR-221/222 expressing MM.1R (Dex-resistant) cells were transfected with agomir-221/222 or antagomir-221/222, respectively, and then the level of autophagy was evaluated. The results showed that overexpression of miR-221/222 reduced the level of autophagy in MM.1S cells, while inhibition of miR-221/222 elevated the level of autophagy in MM.1R cells. Using microRNA target prediction bioinformatics tools and dual-luciferase reporter assay, we confirmed that autophagy-related gene 12 (ATG12) was a novel target gene of miR-221/222. Indeed, miR-221/222 could negatively regulate the expression of ATG12 at both the mRNA and protein levels in MM cells. In addition, knockdown of ATG12 by siRNA markedly reduced the autophagy-inducing and Dex-sensitizing activity of miR-221/222 antagomirs in MM.1R cells. Of note, in MM.1S cells, Dex treatment could further decreased the expression of miR-221/222, accompanied by upregulated expression of ATG12, whereas silencing the expression of ATG12 could significantly inhibited Dex-induced autophagy and cell death. Thus, these results suggest that ATG12 is a key player in miR-221/222-mediated autophagy inhibition and Dex-resistance. Next, we evaluated whether miR-221/222 could regulate autophagy and Dex-sensitivity of MM cells invivo. NOD/SCID mice were subcutaneously injected with MM.1R cells to establish Dex-resistant MM xenografts. Combined treatment with antagomir-221/222 plus Dex showed a remarkable reduction of tumor size compared to antagomir-221/222 or Dex alone (397.6±55.08 mm3 VS 895.8±72.44 mm3 VS 987.3±68.49 mm3). Immunohistochemistry and western blot analysis of the retrieved xenografted tumors showed that combination treatment with antagomir-221/222 plus Dex induced upregulation of ATG12, as well as extended autophagy with increased p62 degradation and Beclin-1 expression. In conclusion, our data reveal that upregulation of miR-221/222 promotes Dex resistance of MM cells through inhibition of autophagy by targeting ATG12. Therefore, miR-221/222-ATG12 autophagy-regulatory axis may potentially be applied in glucocorticoid resistance prediction and treatment. Disclosures No relevant conflicts of interest to declare.

Abstract 29: MiR-33 Coordinately Regulates Macrophage Autophagy

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Mireille Ouimet ◽  
Hasini Ediriweera ◽  
Bhama Ramkhelawon ◽  
Elizabeth Hennessy ◽  
Denuja Karunakaran ◽  
...  
Keyword(s):  
Western Blot ◽  
Quantitative Pcr ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Cholesterol Efflux ◽  
Energy Homeostasis ◽  
Cholesterol Metabolism ◽  
Autophagic Flux ◽  
Microrna Target

Macrophage autophagy is thought to be essential for protecting from atherosclerosis, and compromised autophagy in macrophages of the artery wall leads to a number of pathologic processes including activation of the inflammasome, defective efferocytosis, and impaired cholesterol metabolism. Autophagy of lipid droplets (LDs) or “lipophagy” catabolizes stored lipids to maintain cellular energy homeostasis and plays a key role in cholesterol efflux by regulating LD-cholesterol mobilization, a rate-limiting step in macrophage reverse cholesterol transport (RCT). MicroRNA-33 (miR-33) is a well-established post-transcriptional RCT regulator, yet the complete mechanisms by which anti-miR33 exerts its beneficial effects on cholesterol metabolism are not known. Notably, microRNA target prediction algorithms identify a number of essential autophagy-related proteins (ATG5, ATG7) and lysosomal effectors (lysosomal-associated membrane protein 1 [LAMP1], lysosomal acid lipase [LAL]) as putative miR-33 targets. Quantitative PCR array profiling in mouse peritoneal macrophages revealed that a high proportion of autophagy genes are reciprocally regulated by miR-33 overexpression and inhibition. We validated a subset of genes in the autophagy pathway as bona fide miR-33 targets using 3′UTR luciferase assays and confirmed regulation of these targets by miR-33 using quantitative PCR and western blot analysis. Furthermore, we show that miR-33 indirectly regulates the expression of two master regulators of autophagy and lysosomal biogenesis gene programs: forkhead box O (FOXO) 3 and transcription factor EB (TFEB), via targeting of 5' AMP-activated protein kinase (AMPK). Inhibition of miR-33 in peritoneal macrophage in vitro enhanced cellular autophagic flux, as observed by fluorescence microscopy and western blot analysis, and autophagy was required for anti-miR33 promotion of cholesterol efflux. Furthermore, anti-miR33 treatment of atherosclerotic Ldlr-/- mice enhanced autophagy in plaque macrophages and triggered atherosclerosis regression. These data describe a novel role for miR-33 in the regulation of autophagy and identify additional mechanisms by which anti-miR33 therapy protects against atherosclerosis.

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