Inhibition Of miR-21 Research Articles

Quercetin suppresses retinoblastoma cell proliferation and invasion and facilitates oxidative stress-induced apoptosis through the miR-137/FNDC5 axis

Retinoblastoma (RB) constitutes a prevalent malignancy in clinic and usually occurs in children under the age of 5 years old. The increased frequency of malignant tumor metastases and the delayed diagnosis and treatment caused unsatisfactory therapeutic efficiency. Quercetin was formerly identified to impede tumor growth in certain malignancies. Our study attempted to investigate the effects and mechanisms of quercetin in Rb development, in order to provide an effective clinical therapeutic approach. Rb cell lines (WER1-RB1 and Y79) were incubated with different concentrations of quercetin, and then cell proliferation, invasion, apoptosis, and oxidative stress were determined. It was showed that quercetin restrained Rb cell proliferation and invasion, and induced cell apoptosis and oxidative stress in a dose dependent manner. Moreover, we found that quercetin incubation upregulated miR-137 expression in Rb cells. MiR-137 inhibition abrogated quercetin-mediated inhibition of Rb cell progression. Furthermore, dual-luciferase reporter gene assay validated that fibronectin type III domain-containing protein 5 (FNDC5) was a target for miR-137. MiR-137 overexpression restrained proliferation and invasion, and enhanced apoptosis and oxidative stress in Rb cells, whereas FNDC5 overexpression abrogated these effects. Additionally, nude mice were injected with WER1-RB1 cells to establish a xenograft tumor model, and then treated with 50 or 100 mg/kg quercetin. Quercetin treatment mitigated xenograft tumor growth in nude mice. In conclusion, quercetin restrained proliferation and invasion, and induced apoptosis and oxidative stress in Rb cells through regulating the miR-137/FNDC5 pathway. We expected that our study could provide an effective approach for Rb treatment. However, quercetin and miR-137 may have off-target effects in Rb cells, and our study still has certain limitations. Therefore, we will investigate the effects of quercetin on other signaling pathways in Rb cells and explore the application of combination therapy in follow-up experiments, in order to provide a rigorous research basis for the treatment of Rb with quercetin.

Nanoparticles carrying paclitaxel and anti-miR-221 for breast cancer therapy triggered by ultrasound

Nanomaterials have been well demonstrated to have the potential to be used for tumor cell-targeted drug delivery. Targeted inhibition of miR-221 was proved to promote the sensitivity of triple genitive breast cancer (TNBC) cells to chemo-drugs. In order to improve the chemotherapeutic effect in TNBC, herein, we developed a novel kind of nanoparticles shelled with PLGA and loaded with perfluoropentane (PFP), paclitaxel (PTX), and anti-miR-221 inhibitor, which was named PANP. Ultrasound-triggered vaporization of PFP in PANPs was utilized for real-time imaging track of the nanoparticles in vivo. In addition, macrophages were applied for the internalization of PANPs to form RAW-PANP with strong chemotaxis to accumulate around cancer cells. Nanoparticles with different contents did not cause M2 polarization compared with the control group but caused polarization toward M1. We compared the inherent tumor-homing behavior of macrophages containing different contents with that of normal macrophages and no significant abnormalities were observed. After injection into the tumor-burden mice, RAW-PANPs showed enrichment within tumor tissues. Upon the ultrasound cavitation-triggered burst, PTX was released in the tumor. Meanwhile, the release of anti-miR-221 improved the sensitivity of tumor cells to PTX. As a result, RAW-PANPs showed high efficiency in suppressing TNBC cell proliferation in vitro and inhibiting tumor growth and progression in vivo. The treatments did not induce liver, heart, or kidney injury. In conclusion, the current study not only developed a macrophage-carried, ultrasound-triggered, cancer cell-targeted chemotherapeutic system, but also demonstrated a miRNA-based technique to promote drug sensitivity of cancer cells, which holds strong potential to treat patients with TNBC, especially for those suffering drug-resistance. The innovation of this study is to use macrophages to deliver nanoparticles to the tumors and then use ultrasound locally to burst the nanoparticles to release the miRNA and PTX.

Simultaneous suppression of miR-21 and restoration of miR-145 in gastric cancer cells; a promising strategy for inhibition of cell proliferation and migration.

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. microRNAs are a group of regulatory non-coding RNAs that are involved in GC progression. miR-145 as a tumor suppressor and miR-21 as an oncomiR were shown to be dysregulated in many cancers including GC. This research aimed to enhance the expression of miR-145 while reducing the expression of miR-21 and examine their impact on the proliferation, apoptosis, and migration of GC cells. KATO III cells with high expression levels of miR-21-5p and low expression of miR-145-5p were selected. These cells were then transfected with either miR-145-5p mimics or anti-miR-21-5p, alone or in combination. Afterward, the cell survival rate was determined using the MTT assay, while apoptosis induction was investigated through V-FITC/PI and DAPI staining. Additionally, cell migration was examined using the wound healing assay, and cell cycle progression was analyzed through flow cytometry. Furthermore, gene expression levels were quantified utilizing the qRT-PCR technique. The study's findings indicated that the co-replacement of miR-145-5p and anti-miR-21-5p led to a decrease in cell viability and the induction of apoptosis in GC cells. This was achieved via modulating the expression of Bax and Bcl-2, major cell survival regulators. Additionally, the combination therapy significantly increased sub-G1 cell cycle arrest and reduced cell migration by downregulating MMP-9 expression as an epithelial-mesenchymal transition marker. This study provides evidence for the therapeutic possibility of the combination of miR-145-5p and anti-miR-21-5p and also suggests that they could inhibit cell proliferation by modulating the PTEN/AKT1 signaling pathway. Our research revealed that utilizing miR-145-5p and anti-miR-21-5p together could be a promising therapeutic approach for treating GC.

Targeting miR-223 enhances myeloid-derived suppressor cell suppressive activities in multiple sclerosis patients.

Multiple sclerosis (MS) is an incurable autoimmune inflammatory demyelinating disease of the central nervous system. Several MS medications can modify disease course through effects on adaptive immune cells, while drugs targeting innate immunity are under investigation. Myeloid-derived suppressor cells (MDSCs) which arise during chronic inflammation, are defined by their T-cell immunosuppressive functions. MiR-223 modulates myeloid cell maturation and expansion, including MDSCs. MDSCs isolated from healthy controls (HC) and people with MS (pwMS) were co-cultured with CD4+ T-cells to study their immunosuppressive activities in vitro. Cytokines and chemokines concentration were evaluated by Luminex assay in the serum of HC, pwMS, and other neuroinflammatory diseases and correlated with MDSC activities. MDSC suppressive functions are dysregulated in pwMS compared to HC, which was reversed by glucocorticoids (GC). GC specifically downregulated miR-223 levels in MDSCs and increased the expression of STAT3. In vitro assay showed that miR-223 inhibition enhanced MDSC suppressive activity, STAT3 dependently. By multiple linear regression analysis, we demonstrated that MDSC phosphorylated STAT3 was correlated with serum GM-CSF in HC and pwMS. These results suggest that miR-223 could be a therapeutic target for enhancing MDSC's suppressive activities as an alternative to GC.

Therapeutic inhibition of miR-155 attenuates liver fibrosis via STAT3 signaling

Most chronic liver diseases progress to liver fibrosis, which, when left untreated, can lead to cirrhosis and hepatocellular carcinoma. MicroRNA (miRNA)-targeted therapeutics have become attractive approaches to treat diseases. In this study, we investigated the therapeutic effect of miR-155 inhibition in the bile duct ligation (BDL) mouse model of liver fibrosis and evaluated the role of miR-155 in chronic liver fibrosis using miR-155-deficient (miR-155 knockout [KO]) mice. We found increased hepatic miR-155 expression in patients with cirrhosis and in the BDL- and CCl4-induced mouse models of liver fibrosis. Liver fibrosis was significantly reduced in miR-155 KO mice after CCl4 administration or BDL. To assess the therapeutic potential of miR-155 inhibition, we administered an rAAV8-anti-miR-155 tough decoy invivo that significantly reduced liver damage and fibrosis in BDL. BDL-induced protein levels of transforming growth factor β (TGF-β), p-SMAD2/3, and p-STAT3 were attenuated in anti-miR-155-treated compared with control mice. Hepatic stellate cells from miR-155 KO mice showed attenuation in activation and mesenchymal marker expression. Invitro, miR-155 gain- and loss-of-function studies revealed that miR-155 regulates activation of stellate cells partly via STAT3 signaling. Our study suggests that miR-155 is the key regulator of liver fibrosis and might be a potential therapeutic target to attenuate fibrosis progression.

MicroRNA-124 directly suppresses Nodal and Notch to regulate mesodermal development

MicroRNAs regulate gene expression post-transcriptionally by destabilizing and/or inhibiting translation of target mRNAs in animal cells. MicroRNA-124 (miR-124) has been examined mostly in the context of neurogenesis. This study discovers a novel role of miR-124 in regulating mesodermal cell differentiation in the sea urchin embryo. The expression of miR-124 is first detectable at 12hours post fertilization at the early blastula stage, during endomesodermal specification. Mesodermally-derived immune cells come from the same progenitor cells that give rise to blastocoelar cells (BCs) and pigment cells (PCs) that must make a binary fate decision. We determined that miR-124 directly represses Nodal and Notch to regulate BC and PC differentiation. miR-124 inhibition does not impact the dorsal-ventral axis formation, but result in a significant increase in number of cells expressing BC-specific transcription factors (TFs) and a concurrent reduction of differentiated PCs. In general, removing miR-124's suppression of Nodal phenocopies miR124 inhibition. Interestingly, removing miR-124's suppression of Notch leads to an increased number of both BCs and PCs, with a subset of hybrid cells that express both BC- and PC-specific TFs in the larvae. Removal of miR-124's suppression of Notch not only affects differentiation of both BCs and PCs, but also induces cell proliferation of these cells during the first wave of Notch signaling. This study demonstrates that post-transcriptional regulation by miR-124 impacts differentiation of BCs and PCs by regulating the Nodal and Notch signaling pathways.

A boronate-based modular assembly nanosystem to block the undesirable crosstalk between hepatic stellate cells and Kupffer cells.

Crosstalk between Kupffer cells (KCs) and hepatic stellate cells (HSCs) plays an important role in multiple liver disease conditions, including the formation of liver fibrosis in alcohol-associated liver disease (AALD). Therapeutic targeting of the KC-HSC crosstalk is a prime target for therapeutic interventions. Herein, a novel modular nanosystem was designed and prepared through the self-assembly utilizing boric acid and catechol interactions to prepare polymers modified with a CXCR4-inhibiting moieties. The polymers were used to encapsulate anti-miR-155 and to block the undesirable crosstalk between HSCs and KCs by downregulating miR-155 expression in KCs with the parallel inhibition of CXCR4 signaling in activated HSCs. The combined inhibition of miR-155 and CXCR4 at two different liver cell types achieved improved antifibrosis effects in a mouse model of AALD fibrosis. Our finding highlights the key role that blocking the undesirable crosstalk between HSCs and KCs plays in reversing AALD fibrosis as well as demonstrates a proof-of-concept approach for designing and constructing multifunctional delivery nanosystems using orthogonal functional modules based on the understanding of disease mechanisms.

USF2 activates RhoB/ROCK pathway by transcriptional inhibition of miR-206 to promote pyroptosis in septic cardiomyocytes.

Septic cardiomyopathy (SCM) is one of the most serious complications of sepsis. The present study investigated the role and mechanism of upstream stimulatory factor 2 (USF2) in SCM. Serum samples were extracted from SCM patients and healthy individuals. A murine model of sepsis was induced by caecal ligation and puncture (CLP) surgery. Myocardial injury was examined by echocardiography and HE staining. ELISA assay evaluated myocardial markers (CK-MB, cTnI) and inflammatory cytokines (TNF-α, IL-1β, IL-18). Primary mouse cardiomyocytes were treated with lipopolysaccharide (LPS) to simulate sepsis in vitro. RT-qPCR and Western blot were used for analyzing gene and protein levels. CCK-8 assay assessed cell viability. NLRP3 was detected by immunofluorescence. ChIP, RIP and dual luciferase reporter assays were conducted to validate the molecular associations. USF2 was increased in serum from SCM patients, septic mice and primary cardiomyocytes. USF2 silencing improved the survival of septic mice and attenuated sepsis-induced myocardial pyroptosis and inflammation in vitro and in vivo. Mechanistically, USF2 could directly bind to the promoter of miR-206 to transcriptionally inhibit its expression. Moreover, RhoB was confirmed as a target of miR-206 and could promote ROCK activation and NLRP3 inflammasome formation. Moreover, overexpression of RhoB remarkably reversed the protection against LPS-induced inflammation and pyroptosis mediated by USF2 deletion or miR-206 overexpression in cardiomyocytes. The above findings elucidated that USF2 knockdown exerted a cardioprotective effect on sepsis by decreasing pyroptosis and inflammation via miR-206/RhoB/ROCK pathway, suggesting that USF2 may be a novel drug target in SCM.

Radiofrequency Ablation–Induced Tumor Growth Is Suppressed by MicroRNA-21 Inhibition in Murine Models of Intrahepatic Colorectal Carcinoma

PurposeTo investigate the role of microRNA-21 (miR21) in radiofrequency (RF) ablation–induced tumor growth and whether miR21 inhibition suppresses tumorigenesis. Material and MethodsStandardized liver RF ablation was applied to 35 C57/BL6 mice. miR21 and target proteins pSTAT3, PDCD4, and PTEN were assayed 3 hours, 24 hours, and 3 days after ablation. Next, 53 Balb/c and 44 C57BL/6 mice received Antago-miR21 or scrambled Antago-nc control, followed by intrasplenic injection of 10,000 CT26 or MC38 colorectal tumor cells, respectively. Hepatic RF ablation or sham ablation was performed 24 hours later. Metastases were quantified and tumor microvascular density (MVD) and cellular proliferation were assessed at 14 or 21 days after the procedures, respectively. ResultsRF ablation significantly increased miR21 levels in plasma and hepatic tissue at 3 and 24 hours as well as target proteins at 3 days after ablation (P < .05, all comparisons). RF ablation nearly doubled tumor growth (CT26, 2.0 SD ± 1.0 fold change [fc]; MC38, 1.9 SD ± 0.9 fc) and increased MVD (CT26, 1.9 SD ± 1.0 fc; MC38, 1.5 ± 0.5 fc) and cellular proliferation (CT26, 1.7 SD ± 0.7 fc; MC38, 1.4 SD ± 0.5 fc) compared with sham ablation (P < .05, all comparisons). RF ablation–induced tumor growth was suppressed when Antago-miR21 was administered (CT26, 1.0 SD ± 0.7 fc; MC38, 0.9 SD ± 0.4 fc) (P < .01, both comparisons). Likewise, Antago-miR21 decreased MVD (CT26, 1.0 SD ± 0.3 fc; MC38, 1.0 SD ± 0.2 fc) and cellular proliferation (CT26, 0.9 SD ± 0.3 fc; MC38, 0.8 SD ± 0.3 fc) compared with baseline (P < .05, all comparisons). ConclusionsRF ablation upregulates protumorigenic miR21, which subsequently influences downstream tumor-promoting protein pathways. This effect can potentially be suppressed by specific inhibition of miR21, rendering this microRNA a pivotal and targetable driver of tumorigenesis after hepatic thermal ablation.

The role of miR-21 as a predictive biomarker and a potential target to improve the effects of chemoradiotherapy against head and neck squamous cell carcinoma.

This study aimed to clarify whether circulating miR-21 represents a predictive biomarker in patients with head and neck squamous cell carcinoma (HNSCC) undergoing chemoradiotherapy, and to investigate the effect of miR-21 inhibitor for chemoradiation in human SCC cells. Plasma samples were obtained from 22 patients with HNSCC and 25 non-cancer volunteers. Plasma miR-21 expression was measured using real-time quantitative reverse transcription polymerase chain reaction. The effects of miR-21 inhibitor in human SCC cells were investigated by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and western blot analysis. As a result, plasma miR-21 expression was higher in HNSCC patients than in control patients (P < 0.001). Seven patients with recurrence showed significantly higher plasma miR-21 than the 15 patients without recurrence. And high miR-21 expression group showed poor overall survival. Moreover, miR-21 inhibition significantly enhanced cisplatin- or radiation-induced apoptosis. Western blot analysis suggested the programmed cell death 4 protein as a potential target of miR-21 in relation to apoptosis. In conclusion, this study provides new insights into the role of miR-21 as a predictive biomarker for HNSCC treated with chemoradiotherapy and suggests a potential target to improve the effects of chemoradiotherapy against HNSCC.

Reduction-responsive nucleic acid nanocarrier-mediated miR-22 inhibition of PI3K/AKT pathway for the treatment of patient-derived tumor xenograft osteosarcoma

miRNAs are important regulators of gene expression and play key roles in the development of cancer, including osteosarcoma. During the development of osteosarcoma, the expression of miR-22 is significantly downregulated, making miR-22 as a promising therapeutic target against osteosarcoma. To design and fabricate efficient delivery carriers of miR-22 into osteosarcoma cells, a hydroxyl-rich reduction-responsive cationic polymeric nanoparticle, TGIC-CA (TC), was developed in this work, which also enhanced the therapeutic effects of Volasertib on osteosarcoma. TC was prepared by the ring-opening reaction between amino and epoxy groups by one-pot method, which had the good complexing ability with nucleic acids, reduction-responsive degradability and gene transfection performance. TC/miR-22 combined with volasertib could inhibit proliferation, migration and promote apoptosis of osteosarcoma cells in vitro. The anti-tumor mechanisms were revealed as TC/miR-22 and volasertib could inhibit the PI3K/Akt signaling pathway synergistically. Furthermore, this strategy showed outstanding tumor suppression performance in animal models of orthotopic osteosarcoma, especially in patient-derived chemo-resistant and chemo-intolerant patient-derived xenograft (PDX) models, which reduced the risk of tumor lung metastasis and overcame drug resistance. Therefore, it has great potential for efficient treatment of metastasis and drug resistance of osteosarcoma by the strategy of localized, sustained delivery of miR-22 using the cationic nanocarriers combined with non-traditional chemotherapy drugs.

MicroRNA 9 Is a Regulator of Endothelial to Mesenchymal Transition in Diabetic Retinopathy.

Diabetic retinopathy (DR) is a significant cause of blindness. Most research around DR focus on late-stage developments rather than early changes such as early endothelial dysfunction. Endothelial-to-mesenchymal transition (EndMT), an epigenetically regulated process whereby endothelial cells lose endothelial characteristics and adopt mesenchymal-like phenotypes, contributes to early endothelial changes in DR. The epigenetic regulator microRNA 9 (miR-9) is suppressed in the eyes during DR. MiR-9 plays a role in various diseases and regulates EndMT-related processes in other organs. We investigated the role miR-9 plays in glucose-induced EndMT in DR. We examined the effects of glucose on miR-9 and EndMT using human retinal endothelial cells (HRECs). We then used HRECs and an endothelial-specific miR-9 transgenic mouse line to investigate the effect of miR-9 on glucose-induced EndMT. Finally, we used HRECs to probe the mechanisms through which miR-9 may regulate EndMT. We found that miR-9 inhibition was both necessary and sufficient for glucose-induced EndMT. Overexpression of miR-9 prevented glucose-induced EndMT, whereas suppressing miR-9 caused glucose-like EndMT changes. We also found that preventing EndMT with miR-9 overexpression improved retinal vascular leakage in DR. Finally, we showed that miR-9 regulates EndMT at an early stage by regulating EndMT-inducing signals such as proinflammatory and TGF-β pathways. We have shown that miR-9 is an important regulator of EndMT in DR, potentially making it a good target for RNA-based therapy in early DR.

WED-410 - mir-22 inhibition as glp1 agonist orthogonal mechanism for nafl and nash treatment

WED-410 - mir-22 inhibition as glp1 agonist orthogonal mechanism for nafl and nash treatment

MIR204 POTENTIALLY PROMOTES NON-ALCOHOLIC FATTY LIVER DISEASE BY INHIBITION OF CPT1A IN MOUSE HEPATOCYTES

Objective: Non-alcoholic fatty liver disease (NAFLD) is associated with hepatic metabolism dysfunction. However, the mechanistic role of miR204 in the development of NAFLD is unknown. We investigated the functional significance of miR204 in the evolution of NAFLD. Design and method: NAFLD was induced in isocitrate dehydrogenase (IDH2) knockout (KO) mice by feeding them with a high-fat diet (HFD). Blood parameters and hepatic fat accumulation were evaluated in IDH2 KO mice and wild-type (WT) mice. A miR204 inhibitor was subcutaneously injected into mice using an osmotic pump. The expression of miR204 was analyzed by quantitative PCR (qPCR). Results: IDH2 KO mice fed a normal diet (ND) or HFD showed significantly increased body weight, epididymal fat-pad weight, cholesterol, triglyceride, and macrophage marker (CD68), and inflammatory cytokine [tumor necrosis factor-a (TNF-a), interleukin (IL)-6 and IL-1b] expression compared to WT mice fed a ND or HFD. Moreover, the expression of miR204 was significantly increased in mice with IDH2 deficiency. miR204 regulates carnitine palmitoyltransferase 1a (cpt1a) synthesis, which inhibits fatty acid b-oxidation. Inhibition of miR204 prevents the disassembly of two fatty acid-related genes—peroxisomal acyl-coenzyme A oxidase 1 (ACOX-1) and peroxisome proliferator-activated receptor alpha (PPARa)—by activating CPT1a expression, which decreases inflammatory cytokines, epididymal fat pad weight, cholesterol, low-density lipoprotein (LDL), and triglycerides. Conclusions: miR204 promotes the pathogenesis of HFD-induced NAFLD by regulating hepatic metabolism and inflammation.

Silencing miR-21-5p in sensory neurons reverses neuropathic allodynia via activation of TGFB-related pathway in macrophages.

Neuropathic pain remains poorly managed by current therapies highlighting the need to improve our knowledge of chronic pain mechanisms. In neuropathic pain models, dorsal root ganglia (DRG) nociceptive neurons transfer miR-21 packaged in extracellular vesicles to macrophages that promote pro-inflammatory phenotype and contribute to allodynia. Here we show that miR-21 conditional deletion in DRG neurons was coupled with lack of up-regulation of CCL2 chemokine after nerve injury and reduced accumulation of CCR2-expressing macrophages, which showed TGFB-related pathway activation and acquired M2-like anti-nociceptive phenotype. Indeed, neuropathic allodynia was attenuated in cKO and restored by a TGFB receptor inhibitor (SB431542) administration. Since TGFBR2 and TGFB1 are known miR-21 targets, we suggest that miR-21 transfer from injured neurons to macrophages maintains a pro-inflammatory phenotype via suppression of such an anti-inflammatory pathway. These data support miR-21 inhibition as a possible approach to maintain polarization of DRG macrophages at M2-like state and attenuate neuropathic pain.

MiR-150 regulates the Leishmania infantum parasitic load and granzyme B levels in peripheral blood mononuclear cells of dogs with canine visceral leishmaniosis

Leishmania infantum causes visceral leishmaniosis, a neglected tropical disease that can modulate the host immune response by altering the expression of small non-coding RNAs called microRNAs (miRNAs). Some miRNAs are differentially expressed in peripheral blood mononuclear cells (PBMCs) of dogs with canine visceral leishmaniosis (CanL), like the down-regulated miR-150. Even though miR-150 is negatively correlated with L. infantum parasitic load, it is unclear if miR-150 directly affects L. infantum parasitic load and (if so) how this miRNA would contribute to infection. Here, we isolated PBMCs from 14 naturally infected dogs (CanL group) and six healthy dogs (Control group) and treated them in vitro with miR-150 mimic or inhibitor. We measured L. infantum parasitic load using qPCR and compared treatments. We also measured miR-150 in silico predicted target protein levels (STAT1, TNF-α, HDAC8, and GZMB) using flow cytometry or enzyme-linked immunosorbent assays. Increasing miR-150 activity diminished L. infantum parasitic load in CanL PBMCs. We also found that inhibition of miR-150 reduced GZMB (granzyme B) levels. These findings demonstrate that miR-150 plays an important role in L. infantum infection in canine PBMCs, and they merit further studies aiming at drug development.

Targeting of microRNA-22 Suppresses Tumor Spread in a Mouse Model of Triple-Negative Breast Cancer.

microRNA-22 (miR-22) is an oncogenic miRNA whose up-regulation promotes epithelial-mesenchymal transition (EMT), tumor invasion, and metastasis in hormone-responsive breast cancer. Here we show that miR-22 plays a key role in triple negative breast cancer (TNBC) by promoting EMT and aggressiveness in 2D and 3D cell models and a mouse xenograft model of human TNBC, respectively. Furthermore, we report that miR-22 inhibition using an LNA-modified antimiR-22 compound is effective in reducing EMT both in vitro and in vivo. Importantly, pharmacologic inhibition of miR-22 suppressed metastatic spread and markedly prolonged survival in mouse xenograft models of metastatic TNBC highlighting the potential of miR-22 silencing as a new therapeutic strategy for the treatment of TNBC.

Loss of microRNA-21 protects against acetaminophen-induced hepatotoxicity in mice.

Acetaminophen (APAP)-induced Acute Liver Failure (ALF) is recognized as the most common cause of ALF in Western societies. APAP-induced ALF is characterized by coagulopathy, hepatic encephalopathy, multi-organ failure, and death. MicroRNAs are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. MicroRNA-21 (miR-21) is dynamically expressed in the liver and is involved in the pathophysiology of both acute and chronic liver injury models. We hypothesize that miR-21genetic ablation attenuates hepatotoxicity following acetaminophen intoxication. Eight-week old miR-21knockout (miR21KO) or wild-type (WT) C57BL/6N male mice were injected with acetaminophen (APAP, 300mg/kg BW) or saline. Mice were sacrificed 6 or 24h post-injection. MiR21KO mice presented attenuation of liver enzymes ALT, AST, LDH compared with WT mice 24h post-APAP treatment. Moreover, miR21KO mice had decreased hepatic DNA fragmentation and necrosis than WT mice after 24h of APAP treatment. APAP-treated miR21KO mice showed increased levels of cell cycle regulators CYCLIN D1 and PCNA, increased autophagy markers expression (Map1LC3a, Sqstm1) and protein (LC3AB II/I, p62), and an attenuation of the APAP-induced hypofibrinolytic state via (PAI-1) compared with WT mice 24 post-APAP treatment. MiR-21 inhibition could be a novel therapeutic approach to mitigate APAP-induced hepatotoxicity and enhance survival during the regenerative phase, particularly to alter regeneration, autophagy, and fibrinolysis. Specifically, miR-21 inhibition could be particularly useful when APAP intoxication is detected at its late stages and the only available therapy is minimally effective.

Exosome Derived from Human Umbilical Cord Mesenchymal Cell Exerts Immunomodulatory Effects on B Cells from SLE Patients.

Excessive proliferation and activation of B cells, resulting in the production of various autoantibodies, is a crucial link and significant feature of the pathogenesis of systemic lupus erythematosus (SLE), as well as the pathological basis of systemic multiorgan damage. However, whether exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs-Exo) are involved in the immune regulation of SLE has not been clarified. Therefore, our study aimed to investigate the efficacy of hucMSCs-Exo for treating SLE. hucMSCs-Exo and peripheral blood mononuclear cells (PBMCs) of SLE patients were cocultured in vitro, and B cell apoptosis, activation, proliferation, and inflammation levels were detected by flow cytometry. Subsequently, the expression level of miR-155 in B lymphocytes of SLE patients was detected by qRT-PCR, and the target gene relationship between miR-155 and SHIP-1 was found through bioinformatics and dual luciferase activity experiments, which verified the inhibition of miR-155 in B lymphocytes of SLE patients to regulate immunity. We found that hucMSCs-Exo promoted B cell apoptosis, prevented B cell overactivation, and reduced inflammation. MicroRNA-155 (miR-155) has a powerful regulatory function in B cells. It was demonstrated that hucMSCs-Exo acts synergistically with miR-155 inhibitors to target SHIP-1 to B cells more effectively than exosomes alone. Our results provide insight into how hucMSCs-Exo regulates autoimmunity in patients with lupus and suggest targeting miR-155 for autoimmunity while protecting immunity.

MiR-21 alleviates renal tubular epithelial cells injury induced by ischemia by targeting TLR4

Renal ischemia is the initial stage of kidney damage, leading to mitochondrial metabolism disorders and cell necrosis. In this study, we aimed to investigate the biological functions and potential mechanisms of miR-21 in protecting renal tubular epithelial cells from oxidative stress and apoptosis following oxygen glucose deprivation (OGD). Following an OGD injury, miR-21 levels increased in HK-2 renal tubular epithelial cells. Overexpression of miR-21 decreased the protein expressions of cleaved caspase-3, BAX, P53, cell apoptosis and increased Bcl-2 expression in HK-2 cells with OGD injury. In vivo studies found that miR-21 agomir reduced renal tissue apoptosis, while miR-21 antagomir increased it. In addition, overexpression of miR-21 reduced levels of reactive oxygen species (ROS), malondialdehyde (MDA) and lactate dehydrogenase (LDH) in HK-2 cells with OGD injury. However, miR-21 inhibition exhibited the opposite effect. A dual-luciferase reporter assay demonstrated that miR-21 directly regulates Toll-like receptor 4 (TLR4) by targeting the 3′-UTR of TLR4 mRNA. Overexpression of miR-21 led to decreased TLR4 protein expression, and TLR4 knockdown was shown to greatly increase AKT activity in HK-2 cells by in vitro kinase assay. Additionally, TLR4 knockdown promoted AKT phosphorylation and hypoxia-inducible factor-1α (HIF-1α) expression, while TLR4 overexpression inhibited these processes. Furthermore, AKT activation abolished the effect of TLR4 on HIF-1α, while AKT inhibition decreased the expression of TLR4 on HIF-1α in TLR4 knockdown HK-2 cells. Further study revealed that HIF-1α inhibition abolished the protective effect of miR-21 overexpression on ROS, LDH levels and cell apoptosis in HK-2 cells after OGD injury, which is indicated by increased levels of ROS and LDH, as well as increased cell apoptosis after HIF-1α inhibition in miR-21-treated HK-2 cells. In conclusion, miR-21 defends OGD-induced HK-2 cell injury via the TLR4/AKT/HIF-1α axis.