miR-21 Inhibitor Research Articles

Abstract 15259: The Novel Antisense Oligonucleotide CDR132L Improves Cardiac Function in Heart Failure Across Different Species

Introduction: The chronic progressive condition of heart failure (HF) is, to date, largely irreversible and continues to impose global morbidity. MicroRNAs exert substantial roles in HF progression by orchestrating pathological genes and pathways. Medications directly tackling the roots of the disease are rare, but inhibition of miR-132, a microRNA that was shown to be upregulated upon cardiac remodeling and HF, is a promising approach. Thus, CDR132L, a clinical-stage synthetic antisense oligonucleotide miR-132 inhibitor, can be an innovative therapy for patients with HF. Hypothesis: To examine the effect of CDR132L, different studies were conducted, including in mice and pigs and in a first-inhuman phase 1b safety and tolerability study that revealed preclinical and exploratory efficacy data. Results: MiR-132 transgenic mice developed reduced left-ventricular ejection fraction (LVEF) and cardiac dilatation. CDR132L treatment significantly improved LVEF and reversed cardiac dilatation. The results were confirmed in a porcine transverse aortic constriction model, where the LVEF was significantly improved in the CDR132L treatment group compared to control animals (48.9% vs. 36.1%). In post-MI HF pigs subjected to different treatment and dosing regimens, resulted in a significant and dose-dependent improvement of the cardiac function, illustrated by an up to 10.4% improvement in LVEF to the placebo group at day 56. During a monthly treatment, 87.5% of the animals treated 5x 5 mg/kg with CDR132L showed a ΔLVEF of >7% compared to the placebo group. Additionally, CDR132L improved contractility and the diastolic function by reducing cardiac stiffness. A successful translation of these preclinical results into humans was performed in a CDR132L safety and tolerability Phase 1b clinical trial in HF patients. In an exploratory analysis, the combined endpoint, consisting of patients with a decrease in NT-proBNP levels and/or an absolute increase in LVEF, was significantly met by 79% of the patients in the pharmacodynamically active CDR132L group. Conclusion: Pharmacological miR-132 inhibition by CDR132L improved cardiac function in multi-species models of HF, highlighting the therapeutic potential for clinical use in HF patients.

MicroRNA-93 promotes the pathogenesis of glaucoma by inhibiting matrix metalloproteinases as well as up-regulating extracellular matrix and Rho/ROCK signaling pathways

ObjectiveTo investigate the effect and potential molecular mechanism of microRNA-93 (miR-93) on retinal ganglion cells (RGCs) apoptosis as well as retinal damage in acute glaucoma mice. MethodsRGCs apoptosis were induced by oxygen-glucose deprivation and reperfusion (OGD/R). The pro-apoptotic effect of miR-93 was evaluated by transfecting miR-93 mimics or miR-93 inhibitor into OGD/R-induced RGCs. The viability and apoptosis of RGCs were determined by MTT assay and flow cytometry. Mouse model of acute glaucoma were successfully induced via high intraocular pressure (IOP), and then these model animals were randomly divided into vehicle group, miR-93 mimics group or miR-93 inhibitor group (n = 10), using healthy mice as normal control. Histopathologic changes of retinal tissue were evaluated by Hematoxylin and Eosin (H&E) staining method. Moreover, cell counts of retinal ganglion cell layer and mean thickness of different layers were also determined. Quantitative real-time PCR (qPCR) and western blotting analysis were used to detect the mRNA and protein expression levels of extracellular matrix (ECM), matrix metalloproteinases (MMPs) and Rho/ROCK signaling pathway. ResultsmiR-93 mimics significantly decreased or promoted the viability and apoptosis of OGD/R-induced RGCs, respectively. In addition, miR-93 mimics significantly exacerbated the degree of retinal tissue damage in mice with acute glaucoma, which was accompanied by a decrease in the number of ganglion cell layer (GCL) cells and the thickness of different tissue layers. Moreover, miR-93 mimics significantly increased IOP in mice with acute glaucoma. Significantly, miR-93 inhibitors significantly reversed the above changes. In addition, results of Western blot analysis showed that miR-93 mimics increased and decreased the expression of ECM-associated and MMP-associated proteins, respectively, by activating the Rho/ROCK signaling pathway. In contrast, miR-93 significantly decreased and increased the expression of ECM-associated and MMP-associated proteins, and suppressed the expression of Rho/ROCK signaling pathway-related proteins. ConclusionmiR-93 can promote the development of glaucoma by activating Rho/ROCK signaling pathway to mediate the accumulation of ECM-related proteins as well as the down-regulation of MMP-related proteins.

SARS-CoV-2 primed platelets–derived microRNAs enhance NETs formation by extracellular vesicle transmission and TLR7/8 activation

BackgroundHyperactive neutrophil extracellular traps (NETs) formation plays a key role in the pathogenesis of severe COVID-19. Extracellular vesicles (EVs) are vehicles which carry cellular components for intercellular communication. The association between COVID-19 patients-derived EVs and NETs formation remains elusive.MethodsWe explored the roles of EVs in NETs formation from 40 COVID-19 patients with different disease severities as well as 30 healthy subjects. The EVs-carried microRNAs profile was analyzed using next generation sequencing approach which was validated by quantitative reverse transcription PCR. The regulatory mechanism of EVs on NETs formation was investigated by using an in vitro cell-based assay, including immunofluorescence assay, flow cytometry, and immunoblotting.ResultsCOVID-19 patient–derived EVs induced NETs formation by endocytosis uptake. SARS-CoV-2 spike protein-triggered NETs formation was significantly enhanced in the presence of platelet–derived EVs (pEVs) and this effect was Toll-like receptor (TLR) 7/8- and NADPH oxidase-dependent. Increased levels of miR-21/let-7b were revealed in EVs from COVID-19 patients and were associated with disease severity. We demonstrated that the spike protein activated platelets directly, followed by the subsequent intracellular miR-21/let-7b upregulation and then were loaded into pEVs. The pEVs-carried miR-21 interacted with TLR7/8 to prime p47phox phosphorylation in neutrophils, resulting in NADPH oxidase activation to promote ROS production and NETs enhancement. In addition, miR-21 modulates NF-κB activation and IL-1β/TNFα/IL-8 upregulation in neutrophils upon TLR7/8 engagement. The miR-21 inhibitor and TLR8 antagonist could suppress efficiently spike protein-induced NETs formation and pEVs primed NETs enhancement.ConclusionsWe identified SARS-CoV-2 triggered platelets–derived GU-enriched miRNAs (e.g., miR-21/let-7b) as a TLR7/8 ligand that could activate neutrophils through EVs transmission. The miR-21-TLR8 axis could be used as a potential predisposing factor or therapeutic target for severe COVID-19.

Marrow Mesenchymal Stem Cell-Derived Exosomes Upregulate Astrocytic Glutamate Transporter-1 Expression via miR-124/mTOR Pathway against Oxygen-Glucose Deprivation/Reperfusion Injury.

Experimental investigations have reported the efficacy of marrow mesenchymal stem cell-derived exosomes (MSC-Exos) for the treatment of ischemic stroke. The therapeutic mechanism, however, is still unknown. The purpose of the study is to show whether MSC-Exos increases astrocytic glutamate transporter-1 (GLT-1) expression in response to ischemic stroke and to investigate further mechanisms. An in vitro ischemia model (oxygen-glucose deprivation/reperfusion, OGD/R) was used. MSC-Exos was identified by Western blot (WB) and transmission electron microscopy (TEM). To further investigate the mechanism, MSC-Exos, miR-124 inhibitor, and mimics, and a mTOR pathway inhibitor (rapamycin, Rap) were used. The interaction between GLT-1 and miR-124 was analyzed by luciferase reporter assay. The GLT-1 RNA expression and miR-124 was assessed by quantitative real-time polymerase chain reaction (qRTPCR). The protein expressions of GLT-1, S6, and pS6 were detected by WB. Results demonstrated that MSC-Exos successfully inhibited the decrease of GLT-1 and miR-124 expression and the increase of pS6 expression in astrocytes after OGD/R. miR-124 inhibitor suppressed the effect of MSC-Exos on GLT-1 upregulation after OGD/R. Rapamycin notably decreased pS6 expression with significantly higher GLT-1 expression in astrocytes injured by OGD/R. Luciferase activity of the reporter harboring the wild-type or mutant GLT-1 3'UTR was not inhibited by miR-124 mimics. Further results showed that the inhibiting effect of MSC-Exos on pS6 expression and promoting effect of MSC-Exos on GLT-1 expression could be reversed by miR-124 inhibitor after OGD/R; meanwhile, the above conditions could be reversed again by rapamycin. Results show that miR-124 and the mTOR pathway are involved in regulation of MSC-Exos on GLT-1 expression in astrocytes injured by OGD/R. miR-124 does not directly target GLT-1. MSC-Exos upregulates GLT-1 expression via the miR-124/mTOR pathway in astrocytes injured by OGD/R.

MiR-184 targeting FOXO1 regulates host-cell oxidative stress induced by Chlamydia psittaci via the Wnt/β-catenin signaling pathway.

Chlamydia psittaci is a human pathogen that causes atypical pneumonia after zoonotic transmission. We confirmed that C. psittaci infection induces oxidative stress in human bronchial epithelial (HBEs) cells and explored how this is regulated through miR-184 and the Wnt/β-catenin signaling pathway. miR-184 mimic, miR-184 inhibitor, FOXO1 siRNA, or negative control sequence was transfected into HBE cells cultured in serum-free medium using Lipofectamine 2000. Then, prior to the cells were infected with C. psittaci 6BC, and the cells were treated with or without 30 µM Wnt/β-catenin inhibitor ICG-001. Quantification of reactive oxygen species, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione was carried out according to the manufacturer's protocol using a corresponding assay kit. The outcome of both protein and gene was measured by western blotting or real-time fluorescence quantitative PCR. In C. psittaci-infected HBE cells, miR-184 was upregulated, while one of its target genes, FOXO1, was downregulated. ROS and MDA levels increased, while SOD and GSH contents decreased after C. psittaci infection. When miR-184 expression was downregulated, the level of oxidative stress caused by C. psittaci infection was reduced, and the Wnt/β-catenin signaling pathway was inhibited. The opposite results were seen when miR-184 mimic was used. Transfecting with FOXO1 siRNA reversed the effect of miR-184 inhibitor. Moreover, when the Wnt/β-catenin-specific inhibitor ICG-001 was used, the level of oxidative stress induced by C. psittaci infection was significantly suppressed. miR-184 can target FOXO1 to promote oxidative stress in HBE cells following C. psittaci infection by activation of the Wnt/β-catenin signaling pathway.

Dual scaffold delivery of miR-210 mimic and miR-16 inhibitor enhances angiogenesis and osteogenesis to accelerate bone healing

Angiogenesis is critical for successful bone repair, and interestingly, miR-210 and miR-16 possess counter-active targets involved in both angiogenesis and osteogenesis: miR-210 acts as an activator by silencing EFNA3 & AcvR1b, while miR-16 inhibits both pathways by silencing VEGF & Smad5. It was thus hypothesized that dual delivery of both a miR-210 mimic and a miR-16 inhibitor from a collagen-nanohydroxyapatite scaffold system may hold significant potential for bone repair. Therefore, this systems potential to rapidly accelerate bone repair by directing enhanced angiogenic-osteogenic coupling in host cells in a rat calvarial defect model at a very early 4 week timepoint was assessed. In vitro, the treatment significantly enhanced angiogenic-osteogenic coupling of human mesenchymal stem cells, with enhanced calcium deposition after just 10 days in 2D and 14 days on scaffolds. In vivo, these dual-miRNA loaded scaffolds showed more than double bone volume and vessel recruitment increased 2.3 fold over the miRNA-free scaffolds. Overall, this study demonstrates the successful development of a dual-miRNA mimic/inhibitor scaffold for enhanced in vivo bone repair for the first time, and the possibility of extending this ‘off-the-shelf’ platform system to applications beyond bone offers immense potential to impact a myriad of other tissue engineering areas. Statement of significancemiRNAs have potential as a new class of bone healing therapeutics as they can enhance the regenerative capacity of bone-forming cells. However, angiogenic-osteogenic coupling is critical for successful bone repair. Therefore, this study harnesses the delivery of miR-210, known to be an activator of both angiogenesis and osteogenesis, and miR-16 inhibitor, as miR-16 is known to inhibit both pathways, from a collagen-nanohydroxyapatite scaffold system to rapidly enhance osteogenesis in vitro and bone repair in vivo in a rat calvarial defect model. Overall, it describes the successful development of the first dual-miRNA mimic/inhibitor scaffold for enhanced in vivo bone repair. This ‘off-the-shelf’ platform system offers immense potential to extend beyond bone applications and impact a myriad of other tissue engineering areas.

MiR-21 Participates in Anti-VEGF-Induced Epithelial Mesenchymal Transformation in RPE Cells.

To explore the role and possible mechanism of miR-21 in anti-VEGF drug-induced epithelial-mesenchymal transformation (EMT) in human retinal pigment epithelium (ARPE-19) cells, and to seek more therapeutic targets to improve prognosis vision. ARPE-19 cells were exposed to clinical dosage of bevacizumab and miR-21 expression was measured by real-time polymerase chain reaction (RT-PCR) assay. MiR-21 mimic and inhibitor were transfected into bevacizumab-induced ARPE-19, the expression of α-smooth muscle actin (α-SMA), E-cadherin, and SNAI1 were detected by cell immunofluorescence and Western blotting. Clinical dosage of bevacizumab caused EMT and enhanced miR-21 expression in ARPE-19 cells (P<0.05). The inhibition of miR-21 attenuated the EMT effect of bevacizumab, while overexpression of miR-21 promoted this activity (P<0.05). The SNAI1 was up-regulated by bevacizumab and promotion was partially suppressed by the miR-21 inhibitor and aggravated by the miR-21 mimic (P<0.05). MiR-21 promotes bevacizumab-induced EMT in ARPE cells which is significantly positively correlated with SNAI1. MiR-21 might be a potential miRNA-based therapeutic target for reducing bevacizumab-induced subretinal fibrosis.

Tetramethylpyrazine and paeoniflorin combination (TMP-PF) inhibits angiogenesis in atherosclerosis via miR-126/VEGF/VEGFR2 signaling pathway

Angiogenesis in atherosclerosis (AS) promotes plaque destabilization. miR-126 has a significant role in angiogenesis. Tetramethylpyrazine (TMP) and paeoniflorin (PF) have anti-atherosclerotic effects. However, the miR-126-related mechanisms of TMP and PF combination (TMP-PF) on angiogenesis in AS have not been understood. To explore the mechanism of TMP-PF on angiogenesis in AS targeting miR-126. Human umbilical vein endothelial cells (HUVECs) were assigned into the control, model, TMP-PF, TMP-PF + miR-126 inhibitor, and simvastatin groups. HUVECs were transfected with miR-126 inhibitor or negative control, incubated with oxidized low-density lipoprotein (ox-LDL) to establish AS model, and then treated with TMP-PF or simvastatin. Cell proliferation, migration, and tube formation assays are conducted, and the expression of angiogenesis-related factors were detected by enzyme-linked immunosorbent assay (ELISA) and Western blotting. The expression level of miR-126 was confirmed by polymerase chain reaction (PCR).ox-LDL promoted HUVECs proliferation, migration, and tube formation, downregulated miR-126 expression, and increased the expression of VEGF, VEGFR2, bFGF, and FGFR1. TMP-PF inhibited proliferation, migration, and tube formation, upregulated miR-126 expression and decreased the expression of VEGF, VEGFR2, bFGF, and FGFR1 in ox-LDL-induced HUVECs. However, the effects of TMP-PF on angiogenesis and the expression of miR-126, VEGF, VEGFR2, and FGFR1 were abolished by miR-126 inhibitor. TMP-PF suppressed angiogenesis in AS by regulating miR-126/VEGF/VEGFR2 pathway, which might elucidate the underlying mechanism of TMP-PF in alleviating AS.

Extracellular shuttling miR-21 contributes to esophageal cancers and human umbilical vein endothelial cell communication in the tumor microenvironment and promotes tumor angiogenesis by targeting phosphatase and tensinhomolog.

Cell-cell communication by carcinoma-derived exosomes can influence the tumor microenvironment (TME) and regulate cancer progression. Based on the overexpression of microRNA-21-5p (miR-21) in plasma from patients diagnosed with esophageal squamous cell carcinoma (ESCC) and exosomes from ESCC cell lines identified earlier, this study aimed to explore the influence of exosomal miR-21 within the TME. ScRNA-Seq and Bulk RNA-Seq were integrated to elucidate the communication between cancer and endothelial cells. The functionality and mechanisms by which exo-miR-21 derived from carcinoma regulate endothelial cell-mediated angiogenesis were assessed using a cocultivation model of EC9706 cells and recipient human umbilical vein endothelial cells (HUVECs), through blood vessel formation experiments, luciferase reporter assays, RT-qPCR, and western blot analysis. A total of 3842 endothelial cells were extracted from the scRNA-seq data of ESCC samples and reclustered into five cell subtype. Cell-cell communication analysis revealed cancer cells presented a strong interaction with angiogenesis-like endothelial cells in secreted signaling. MiR-21 was unregulated in ESCC and the carcinoma-derived exo-miR-21 was significantly raised in HUVECs. The exo-miR-21 promoted the proliferation and migration of HUVECs while also enhancing, closed mesh count, and junction number in HUVECs. Mechanistically, dual-luciferase reporter assay revealed that PTEN was the target of miR-21. Meanwhile, p-Akt was significantly increased and suppressed by inhibition of miR-21 and PI3K inhibitor LY294002. Exo-miR-21-mediated communication between endothelial and cancer cells plays a pivotal role in promoting the angiogenesis of ESCC. Therefore, controlling exo-miR-21 could serve as a novel therapeutic strategy for ESCC by targeting angiogenesis.

Exosomal microRNA-223 from neutrophil-like cells inhibits osteogenic differentiation of PDLSCs through the cGMP-PKG signaling pathway.

Neutrophils-derived exosomes have been shown to cause tissue inflammation in many diseases, but their role in periodontitis, a neutrophil-mediated disease, is unknown. Here, we investigated the effect of neutrophil-like cells derived exosomes on osteogenic dysfunction of periodontal ligament stem cells (PDLSCs) in periodontitis. Neutrophil-like cells were derived from HL-60 cells by dimethylsulfoxide stimulation. Exosomes were isolated by ultracentrifugation and characterized using transmission electron microscopy, nanoflow cytometry and western blot. MicroRNA-223 (miR-223) expression were analyzed by real-time PCR. Western blot, alkaline phosphatase (ALP), and alizarin red staining were conducted to assess whether exosomes could affect the osteogenic differentiation of PDLSCs. The expression of miR-223 was inhibited in PDLSCs by transfecting with miR-223 inhibitor. Cyclic guanosine monophosphate (cGMP) expression was determined by enzyme-linked immunosorbent assay. We found that miR-223 was significantly increased in neutrophils and neutrophil-like cells derived exosomes. Treatment with exosomes derived from neutrophil-like cells upregulated miR-223 expression and inhibited the osteogenic differentiation of PDLSCs, while transfection with miR-223 inhibitor significantly promoted PDLSCs osteogenic differentiation. In addition, co-treatment with KT5823, a cGMP-PKG pathway inhibitor, markedly abrogated the rescue effects of miR-223 inhibitor on the osteogenic differentiation of PDLSCs. Our findings suggest that neutrophil-like cells derived exosomes might inhibit osteogenic differentiation of PDLSCs by transporting miR-223 and regulating the cGMP-PKG signaling pathway.

Milk-Derived Small Extracellular Vesicles Promote Osteogenic Differentiation and Inhibit Inflammation via microRNA-21.

Chronic apical periodontitis (CAP) is a disease with characteristics of inflammation and bone loss. In this study, our objective was to examine the function of small extracellular vesicles (sEVs) obtained from milk in encouraging osteogenic differentiation and inhibiting inflammation by miR-21 in CAP. The expression of miR-21 was detected using qRT-PCR in human CAP samples. The impact of miR-21 on the process of osteogenic differentiation was investigated using CCK-8, qRT-PCR, immunofluorescence staining, and Western blot analysis. The evaluation of RAW 264.7 cell polarization and the assessment of inflammatory factor expression were conducted through qRT-PCR. The influence of sEVs on MC3T3-E1 cells and RAW 264.7 cells was examined, with a particular emphasis on the involvement of miR-21. In human CAP samples, a decrease in miR-21 expression was observed. MiR-21 increased the expression of osteogenesis-related genes and M2 polarization genes while decreasing the expression of M1 polarization genes and inflammatory cytokines. Treatment with milk-derived sEVs also promoted osteogenesis and M2 polarization while inhibiting M1 polarization and inflammation. Conversely, the addition of miR-21 inhibitors resulted in opposite effects. Our results indicated that sEVs derived from milk had a positive effect on bone formation and activation of anti-inflammatory (M2) macrophages and simultaneously reduced inflammation by regulating miR-21 in CAP.

Influenza a virus regulates interferon signaling and its associated genes; MxA and STAT3 by cellular miR-141 to ensure viral replication

The antiviral response against influenza A virus (IAV) infection includes the induction of the interferon (IFN) signaling pathway, including activation of the STATs protein family. Subsequently, antiviral myxovirus resistance (MxA) protein and other interferon-stimulated genes control virus replication; however, the molecular interaction of viral-mediated IFN signaling needs more investigation. Host microRNAs (miRNAs) are small non-coding molecules that posttranscriptionally regulate gene expression. Here, we sought to investigate the possible involvement of miR-141 in IAV-mediated IFN signaling. Accordingly, the microarray analysis of A549 cells transfected with precursor miR-141 (pre-miR-141) was used to capture the potentially regulated genes in response to miR-141 overexpression independent of IAV infection. The downregulation of targeted genes by miR-141, in addition to viral gene expression, was investigated by quantitative real-time PCR, western blot analysis, and flow cytometric assay. Our findings showed a significant upregulation of miR-141 in infected A549 cells with different strains of IAV. Notably, IAV replication was firmly interrupted in cells transfected with the miR-141 inhibitor. While its replication significantly increased in cells transfected with pre-miR-141 confirming the crucial role of miRNA-141 in supporting virus replication. Interestingly, the microarray data of miR-141 transduced A549 cells showed many downregulated genes, including MxA, STAT3, IFI27, and LAMP3. The expression profile of MxA and STAT3 was significantly depleted in infected cells transfected with the pre-miR-141, while their expression was restored in infected cells transfected with the miR-141 inhibitor. Unlike interleukin 6 (IL-6), the production of IFN-β markedly decreased in infected cells that transfected with pre-miR-141, while it significantly elevated in infected cells transfected with miR-141 inhibitor. These data provide evidence for the crucial role of miR-141 in regulating the antiviral gene expression induced by IFN and IL-6 signaling during IAV infection to ensure virus replication.

MiR-375 promotes cisplatin sensitivity of lung adenocarcinoma

BackgroundCisplatin-based chemotherapy has been widely used in the treatment of lung adenocarcinoma (LUAD). However, the development of cisplatin resistance becomes a major obstacle impeding the curative effect. It remains necessary to uncover the molecular mechanism of cisplatin resistance. MethodsBased on the CCLE database, lung cancer cell lines were divided into cisplatin-resistant and cisplatin-sensitive groups. The differentially expressed miRNAs were filtered and further identified by survival prognosis analysis. After transfection with miR-375 inhibitor or mimic, cell cytotoxicity assay, flow cytometry and western blot were conducted to validate the role of miR-375. The transcription factor (TF)-miRNA network was constructed based on TransmiR. The target genes of miR-375 were predicted by Starbase and further verified by RT-qPCR and immunohistochemistry results in the Human Protein Atlas. Functional enrichment analysis was performed with GO terms and KEGG. ResultsIn this study, miR-375 showed the ability to promote cisplatin sensitivity and apoptosis of LUAD. Genes correlated with miR-375 in LUAD were analyzed and ABCC8 showed the strongest positive correlation. Moreover, transcription factors that regulate miR-375 expression were predicted. MBNL1, PTPN3, PRKD1 and RPN1 were identified as the target genes of miR-375. Enrichment analysis demonstrated that miR-375-related genes associated with promoting cell proliferation and anti-apoptosis were involved in the MAPK signaling pathway. ConclusionOverall, this study provides new insights into the role of miR-375 in the cisplatin sensitivity of LUAD. Our present findings may serve as a theoretical basis for new therapeutic strategies and predictive models of cisplatin resistance in LUAD.

Abstract P2126: Role Of Microrna-98 In Myocardial Ischemia-reperfusion Injury In Late Pregnancy

Background: We have shown that the late-pregnant (LP) rodent is more vulnerable to myocardial ischemia-reperfusion injury (IRI) compared to non-pregnant (NP). The molecular mechanisms are unknown. Several microRNAs (miRs) are dysregulated in IRI, making them promising therapeutic targets. Methods: The left anterior descending coronary artery (LAD) of female Sprague-Dawley rats (2-3 months old NP and LP, 20-21 days pregnant) was occluded for 45 minutes followed by 3 hours reperfusion. Myocardial necrosis was assessed using TTC staining. MicroRNA-microarray profiling was performed on hearts of NP and LP rats subjected to IRI. In vitro, female cardiomyocytes were transfected either miR98 mimic or inhibitor, followed by 3 hours hypoxia and 6 hours reoxygenation. Blood samples were collected from NP, LP, and coronary heart disease (CHD) patients. To assess therapeutic potential of miR, miR98 inhibitor was administered at the onset of reperfusion. Results: MicroRNA-microarray profiling revealed miR-98-5p (miR-98) is upregulated in the hearts of LP IRI rats compared to NP IRI by 2.3 folds, which we confirmed with qPCR. miR98 is significantly increased in the plasma of healthy LP compared to healthy NP women, and significantly increased in LP with CHD compared to healthy LP. TargetScan revealed STAT3 and PGC-1α to be targets of miR98. We confirmed significantly decreased expression of STAT3 and PGC-1α in LP IRI rat myocardium compared to NP IRI. MiR98 overexpression in female cardiomyocytes subjected to hypoxia/reoxygenation (H/R) decreased STAT3 and PGC-1α, and increased apoptosis, inflammation, and oxidative stress, while miR-98 knockdown resulted in the opposite effect. Therapeutic targeting of microRNA-98-5p in LP rats subjected to IRI reduced infarct size, apoptosis, oxidative stress, and inflammatory markers via upregulating Stat3 and Pgc-1α. Conclusions: MiR98 is upregulated in LP rats subjected to IRI compared to NP IRI and in LP human plasma samples with CHD compared to healthy NP and LP. miR98 promotes oxidative stress, inflammation, and apoptosis in the setting of H/R in vitro by targeting STAT3 and PGC-1α. Inhibition of miR-98 in LP rats reduces myocardial infarct size, apoptosis, oxidative stress, and inflammation via Stat3 and Pgc-1α.

Abstract P1115: Epicardial Signaling Regulates Myocardial Contractility Via Mirna

Background: A congenital left ventricular aneurysm is a rare cardiac malformation that maycause heartfailure, ventricular wall rupture, ventricular arrythmia or sudden cardiac death. However, mechanisms of congenital left ventricular aneurysm are not known. Paracrinesignals from cardiomyocytes, such as a cardiokine, prokineticin-2, can activate EPDCsdifferentiation in adult heart to promote neovascularization. How the reciprocal interaction viaprokineticin and miRs from epicardium to cardiomyocytes affect heart growth and function,and how EMT-related events contributecardiomyocyte proliferation and function areunknown. MicroRNA (miR124) has an important role in the adult heart, however, its role incardiac development is unknown. Results: Here in this study, by deletion of a prokineticin-2 receptor PKR1 through epicardialcell linage tracing at the different developmental stages of mice embryos, we found that thesemice exhibited ventricular rupture and embryonic lethality. Indeed, miR-124 was significantlyupregulated in PKR1 -deficient epicardial cells both in vitro and in vivo , whereas ectopicexpression of these miRs in epicardial cells resulted in the reduced expression of SNAI2 andsubsequently led to impaired EMT and EMT-related events such impaired migration andincreased apoptosis. Wild type mice cardiomyocytes that were cultured in condition mediumderived from PKR1-deficient epicardial cells had a lower beating rate and contractility. Treatment of the cardiomyocytes with miR-124mimic exhibited the same phenotype, that wasrestored by miR-124 inhibitor, indicating involvement of mir124 in epicardium-cardiomyocyte communication and regulation of cardiomyocyte contractility. Conclusion: These finding reveals a key signaling pathway in which a cardiokine,prokineticin-2 promotes EMT to form EPDCs and their migration in an autocrine manner, andsupports myocardial growth and contractility through repressing miR124. Our study mayprovide novel insight in etiology of congenital defects and new strategies to promotemyocardial regeneration.

Inhibition of miR-25 Ameliorates Cardiac Dysfunction and Fibrosis by Restoring Krüppel-like Factor 4 Expression.

Cardiac hypertrophy is an adaptive response to various pathological insults, including hypertension. However, sustained hypertrophy can cause impaired calcium regulation, cardiac dysfunction, and remodeling, accompanied by cardiac fibrosis. Our previous study identified miR-25 as a regulator of SERCA2a, and found that the inhibition of miR-25 improved cardiac function and reduced fibrosis by restoring SERCA2a expression in a murine heart failure model. However, the precise mechanism underlying the reduction in fibrosis following miR-25 inhibition remains unclear. Therefore, we postulate that miR-25 may have additional targets that contribute to regulating cardiac fibrosis. Using in silico analysis, Krüppel-like factor 4 (KLF4) was identified as an additional target of miR-25. Further experiments confirmed that KLF4 was directly targeted by miR-25 and that its expression was reduced by long-term treatment with Angiotensin II, a major hypertrophic inducer. Subsequently, treatment with an miR-25 inhibitor alleviated the cardiac dysfunction, fibrosis, and inflammation induced by Angiotensin II (Ang II). These findings indicate that inhibiting miR-25 not only enhances calcium cycling and cardiac function via SERCA2a restoration but also reduces fibrosis by restoring KLF4 expression. Therefore, targeting miR-25 may be a promising therapeutic strategy for treating hypertensive heart diseases.

Inhibitory Effect of Resveratrol on the Proliferation of Multiple Myeloma Cells and the Underlying Mechanism

To investigate the effect of resveratrol (RSV) on the proliferation of multiple myeloma (MM) cells and its molecular mechanism. MM cells (MM1.S, RPMI-8226 and U266) were treated with different concentrations of RSV for 24-72 h. The effect of RSV on the proliferation of MM cells was detected by CCK-8 (cell counting kit-8) assay. RPMI-8226 cells were divided into RSV, miR-21 mimic, RSV+miR-21 mimic, miR-21 inhibitor and RSV+miR-21 inhibitor groups, and transfected with corresponding plasmids. The cell cycle distribution of each group was detected by flow cytometry with propidium iodide (PI) single staining. The cell apoptosis of each group was detected by AnnexinV-FITC/PE-PI double staining. The expression of miR-21 in MM cells treated with RSV and the expression of KLF5 mRNA in each group were detected by qRT-PCR. The expression of KLF5 protein in each group was detected by Western blot. RSV inhibited the proliferation and induced apoptosis of MM cells in a time- and dose-dependent manner. After the MM cells were treated with RSV, the number of cells in sub-G1 phase was increased, and that in G2/M phase was decreased. Moreover, RSV significantly downregulated the expression of miR-21 in MM cells, and the inhibitory effect of miR-21 mimic on KLF5 expression in MM cells was counteracted by RSV. RSV may inhibit the proliferation and induce apoptosis of MM cells by inhibiting miR-21 and up-regulating KLF5 expression.

Modifications of The Human Liver Cancer Cells through microRNA-145-Mediated Targeting of CDCA3.

Owing to the lethality of liver cancer, it is considered as one of the devastating types of cancers across the globe. Consistently, the study was designed to elucidate the role and to explore the therapeutic implications of miR-145 in human liver cancer. In the current experimental study, gene expression was determined by RT-PCR analysis. Transfection of cancer cells was carried out using Lipofectamine 2000. The cell proliferation of liver cancer cells was estimated by MTT assay. Clonogenic assay was performed for analysis of colony forming potential of cancer cells. Flow cytometry was done to analyze the cell cycle phase distribution of cancer cells. Transwell chamber assay was performed to assess the motility of cancer cells. Western blotting was done to estimate the expression levels of proteins. Dual luciferase assay was performed for interaction analysis of miR-145 with CDCA3. The miR-145 expression was found to be downregulated in liver cancer cells. The transfection mediated overexpression of miR-145 inhibited the cancer cell proliferation and when miR-145 inhibitor was transfected, cancer cells showed higher proliferation rates. Enrichment of miR-145 levels led to cell cycle arrest at G2/M phase by inhibiting cyclin B1. miR-145 also restricted the migration and invasion of cancer cells. CDCA3 was shown to be the intracellular target of miR-145 and it was found that the inhibitory effects of miR-145 were modulated through CDCA3, intracellularly. The current study clearly revealed that there is a need to investigate the regulatory role of different molecular entities like microRNAs in cancer development to better understand mechanics behind this pathogenesis and design more effective combating strategies against cancer.

Intravenous Delivery of miR-21 Inhibitor in Mice With Head and Neck Squamous Cell Carcinoma.

Synthetic miRNA inhibitors have recently attracted considerable interest as potential therapeutic agents for head and neck squamous cell carcinoma. However, due to the lack of evidence, no attempts have been made to deliver these inhibitors intravenously for squamous cell carcinoma. This study investigated whether intravenous administration of a miR-21 inhibitor with lipid nanoparticles could suppress HNSCC in xenograft mice. Head and neck squamous cell carcinoma xenograft mice were intravenously injected with Invivofectamine 3.0® containing either a miR-21 inhibitor or a control inhibitor, using a modified protocol for nucleic acid encapsulation. Quantitative PCR was used to measure the expression level of intratumoral miR-21. And TdT-mediated dUTP nick-end labeling (TUNEL) immunohistochemistry was used to assess cell death. Intravenous injection of miR-21 inhibitor significantly inhibited head and neck squamous cell carcinoma growth and miR-21 expression in tumor tissue compared to the control inhibitor. TUNEL assay showed significant apoptosis of tumor cells after intravenous administration of miR-21 inhibitor. Intravenous delivery of a miR-21 inhibitor with lipid nanoparticles is a promising approach for miRNA-targeted therapy of head and neck squamous cell carcinoma.

Mesenchymal stem cells, as glioma exosomal immunosuppressive signal multipliers, enhance MDSCs immunosuppressive activity through the miR-21/SP1/DNMT1 positive feedback loop

BackgroundThe immunosuppressive microenvironment in glioma induces immunotherapy resistance and is associated with poor prognosis. Glioma-associated mesenchymal stem cells (GA-MSCs) play an important role in the formation of the immunosuppressive microenvironment, but the mechanism is still not clear.ResultsWe found that GA-MSCs promoted the expression of CD73, an ectonucleotidase that drives immunosuppressive microenvironment maintenance by generating adenosine, on myeloid-derived suppressor cells (MDSCs) through immunosuppressive exosomal miR-21 signaling. This process was similar to the immunosuppressive signaling mediated by glioma exosomal miR-21 but more intense. Further study showed that the miR-21/SP1/DNMT1 positive feedback loop in MSCs triggered by glioma exosomal CD44 upregulated MSC exosomal miR-21 expression, amplifying the glioma exosomal immunosuppressive signal. Modified dendritic cell-derived exosomes (Dex) carrying miR-21 inhibitors could target GA-MSCs and reduce CD73 expression on MDSCs, synergizing with anti-PD-1 monoclonal antibody (mAb).ConclusionsOverall, this work reveals the critical role of MSCs in the glioma microenvironment as signal multipliers to enhance immunosuppressive signaling of glioma exosomes, and disrupting the positive feedback loop in MSCs with modified Dex could improve PD-1 blockade therapy.Graphical abstract