Targeting miR-21 Research Articles

Targeted Microglial Membrane-Coated MicroRNA Nanosponge Mediates Inhibition of Glioblastoma.

Glioblastoma (GBM) is the most prevalent primary brain tumor. Recent research emphasizes the crucial role of microRNAs (miRs) in GBM pathogenesis, and targeting miRs offers an effective approach for precise GBM therapy. However, inhibiting a single miR may not be sufficient due to the compensatory mechanisms of GBM. Herein, we developed a miR-nanosponge capable of specifically capturing multiple miRs involved in tumor growth, migration, invasion, angiogenesis, and the creation of an immunosuppressive microenvironment, thereby offering a comprehensive treatment for GBM. Coated with BV2 cell membrane (BM) for enhanced blood-brain barrier (BBB) crossing and GBM targeting, the BM@miR-nanosponge targets miR-9, miR-21, miR-215, and miR-221, significantly inhibiting GBM progression and modulating the immune system for a thorough GBM eradication. The BM@miR-nanosponge notably extended the median survival time of GBM-bearing mice and outperformed the standard treatment drug temozolomide (TMZ). This study introduces a comprehensive miR-based strategy for GBM treatment and highlights the importance of targeting multiple miRs associated with tumor survival for effective therapy.

Lnc NBAT1 Inhibits the Proliferation and Migration of Liver Cancer Cells Through the miR-21/PDCD4/AP-1 Signaling Axis.

Long non-coding RNAs (Lnc RNAs) are proven to participate in liver cancer (LC) regulation. The regulation of miR-21 by lnc NBAT1 has been studied in other cancers. However, the effect of this regulation on LC and its specific mechanism remains unclear. Lnc NBAT1 and miR-21 expressions in clinical tissues were measured by RT-qPCR. PDCD4, AP-1, p-c-Fos, p-c-Jun, and cyclin D1 expressions were analyzed by Western blot. Overexpression of lnc NBAT1 was studied to explore its influence on malignant behaviors of Bel7402 cells and the development of LC in the xenograft mouse model (XMM). The regulation mechanism of lnc NBAT1 in LC was explored by lnc NBAT1 overexpression, miR-21 mimic treatment, or PDCD4 silencing in Bel7402 cells. Lnc NBAT1 expression was downregulated while miR-21 expression was upregulated in LC tissues and cell lines. In comparison with LX-2 cells, the expressions of PDCD4 and AP-1 were downregulated in Bel7402 cells, while those of p-c-Fos, p-c-Jun, and cyclin D1 were upregulated. Further, lnc NBAT1 was found to localize primarily in the cytoplasm of Bel7402 cells. Overexpression of lnc NBAT1 enhanced cell apoptosis, blocked the cell cycle, suppressed malignant behaviors of Bel7402 cells, and inhibited tumor progression in the XMM. Mechanistically, lnc NBAT1 functioned as a competing endogenous RNA (ceRNA) by binding to the downstream target miR-21 to stabilize the expressions of PDCD4 and AP-1, thereby inhibiting malignant behaviors of Bel7402 cells. Lnc NBAT1 suppressed malignant behaviors of LC cells through the miR-21/PDCD4/AP-1 axis. Lnc NBAT1 might be a promising biomarker for LC treatment.

AB060. Autophagy-associated biomarkers ULK2, UVRAG, and miRNAs miR-21, miR-126, and miR-374: prognostic significance in glioma patients.

Autophagy is a self-renewing process of the cell having a dual role in gliomagenesis depending on the tumor stage. Several microRNAs play a key role in the regulation of autophagy and the outcome of cancer. We investigated the potential relevance of autophagy in gliomagenesis and survival by exploring the association of the basal gene expression of autophagy-associated markers LC3, ULK1/2, UVRAG, Beclin1, mTOR, UVRAG, PI3K, AKT, PTEN and their target microRNAs miR-126, miR-374, miR-21, miR-7, miR-204 and miR-100 in low- and high-grades of gliomas. A total of 50 fresh glioma tissues were used for the extraction of RNA using TRIzol-Chloroform method and reverse transcribed cDNA. The cDNA was used to determine the expression of genes and microRNAs using quantitative real-time polymerase chain reaction (qPCR). Mann-Whitney U-test was used to determine the statistical significance. In high-grade glioma, increased expression of AKT and miR-21, coupled with reduced ULK2 and LC3 expression was distinctly observed. While correlation analysis identified a strong positive correlation between ULK2 and UVRAG, PTEN, miR-7, and miR-100 and a moderate positive correlation emerged between ULK2 and mTOR, miR-7, miR-30, miR-100, miR-204, and miR-374, also between miR-21 and miR-126 in low-grade glioma. Similarly, a positive correlation appeared between ULK2 and AKT, LC3, PI3K, PTEN, ULK1, VPS34, mTOR, Beclin1, UVRAG, miR-7 and miR-374. AKT positively correlated with LC3, PI3K, PTEN, ULK1, VPS34, mTOR, Beclin1, UVRAG, miR-7, miR-30, miR-204, miR-374, miR-126 and miR-21 weakly correlated with AKT and miR-30 in high-grade glioma. The low ULK2, UVRAG, and miR-374 expression group exhibited significantly poor overall survival in glioma, while miR-21 over-expression indicated a poor prognosis in glioma patients. This study provides comprehensive insights into the molecular landscape of gliomas, highlighting the dysregulation of autophagy genes ULK2, and UVRAG and the associated miR-21, miR-126 and miR-374 as potential prognostic biomarkers and emphasizing their unique significance in shaping survival outcomes in gliomas patients.

LncRNA PTENP1/miR-21/PTEN Axis Modulates EMT and Drug Resistance in Cancer: Dynamic Boolean Modeling for Cell Fates in DNA Damage Response.

It is well established that microRNA-21 (miR-21) targets phosphatase and tensin homolog (PTEN), facilitating epithelial-to-mesenchymal transition (EMT) and drug resistance in cancer. Recent evidence indicates that PTEN activates its pseudogene-derived long non-coding RNA, PTENP1, which in turn inhibits miR-21. However, the dynamics of PTEN, miR-21, and PTENP1 in the DNA damage response (DDR) remain unclear. Thus, we propose a dynamic Boolean network model by integrating the published literature from various cancers. Our model shows good agreement with the experimental findings from breast cancer, hepatocellular carcinoma (HCC), and oral squamous cell carcinoma (OSCC), elucidating how DDR activation transitions from the intra-S phase to the G2 checkpoint, leading to a cascade of cellular responses such as cell cycle arrest, senescence, autophagy, apoptosis, drug resistance, and EMT. Model validation underscores the roles of PTENP1, miR-21, and PTEN in modulating EMT and drug resistance. Furthermore, our analysis reveals nine novel feedback loops, eight positive and one negative, mediated by PTEN and implicated in DDR cell fate determination, including pathways related to drug resistance and EMT. Our work presents a comprehensive framework for investigating cellular responses following DDR, underscoring the therapeutic potential of targeting PTEN, miR-21, and PTENP1 in cancer treatment.

Enzyme-Assisted Colorimetric Salivary miR-21 Detection by Functional Gold Nanoparticles

miRNA-21 (miR-21) is a potential biomarker for the monitoring of diseases through its expression levels. Simple, portable and sensitive miR-21 detection of is advantageous for health monitoring in Point of Care Testing (POCT). Gold nanoparticles (AuNP) as excellent colorimetric sensors are widely used in the POCT. However, their low sensitivity is a limitation of their clinical use. Herein, we developed an AuNPs-based miR-21 assay with enzyme-assisted amplification reaction to construct the colorimetric platform capable of detecting as low as 0.1[Formula: see text]nM. In this platform, template ssDNA as a signal molecule could hybridize with ssDNA-modified AuNPs to generate the color reaction. The target miR-21 specifically hybridized to the template ssDNA, which was then cleaved by exonuclease III (Exo III) to release the target miR-21. As a trigger, miR-21 catalyzed the degradation of the template ssDNA to amplify the signal by Exo III. By hybridizing miR-21 and template ssDNA in the presence of Exo III, R-21 induced a significant decrease in the level of template ssDNA to reduce the aggregation of AuNPs. There is a clear color difference in the presence/absence of miR-21 in the assay. In this assay, the optimal concentration of templated ssDNA and Exo III were 100[Formula: see text]nM and 0.06[Formula: see text]U/[Formula: see text]L in a 100[Formula: see text][Formula: see text]L detection system. The LoD for UV–Vis spectrum and colorimetric reaction were 0.1[Formula: see text]nM and 0.5[Formula: see text]nM, respectively. The detection system has good selectivity and can be used to detect miR-21 in the simulated saliva. It has great potential for application in biomedical research as well as in clinical diagnostics.

SERS biosensors based on catalytic hairpin self-assembly and hybridization chain reaction cascade signal amplification strategies for ultrasensitive microRNA-21 detection.

A highly sensitive surface-enhanced Raman scattering (SERS) biosensor has been developedfor the detection of microRNA-21 (miR-21) using an isothermal enzyme-free cascade amplification method involving catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR). The CHA reaction is triggered by the target miR-21, which causes hairpin DNA (C1 and C2) to self-assemble into CHA products. After AgNPs@Capture captures the resulting CHA product, the HCR reaction is started, forming long-stranded DNA on the surface of AgNPs. A strong SERS signal is generated due to the presence of a large amount of the Raman reporter methylene blue (MB) in the vicinity of the SERS "hot spot" on the surface of AgNPs. The monitoring of the SERS signal changes of MB allows for the highly sensitive and specific detection of miR-21. In optimal conditions, the biosensor exhibits a satisfactory linear range and a low detection limit for miR-21 of 42.3 fM. Additionally, this SERS biosensor shows outstanding selectivity and reproducibility. The application of this methodology to clinical blood samples allows for the differentiation of cancer patients from healthy controls. As a result, the CHA-HCR amplification strategy used in this SERS biosensor could be a useful tool for miRNA detection and early cancer screening.

The Multifaceted Role of miR-21 in Pancreatic Cancers.

With the lack of specific signs and symptoms, pancreatic ductal adenocarcinoma (PDAC) is often diagnosed at late metastatic stages, resulting in poor survival outcomes. Among various biomarkers, microRNA-21 (miR-21), a small non-coding RNA, is highly expressed in PDAC. By inhibiting regulatory proteins at the 3' untranslated regions (UTR), miR-21 holds significant roles in PDAC cell proliferation, epithelial-mesenchymal transition, angiogenesis, as well as cancer invasion, metastasis, and resistance therapy. We conducted a systematic search across major databases for articles on miR-21 and pancreatic cancer mainly published within the last decade, focusing on their diagnostic, prognostic, therapeutic, and biological roles. This rigorous approach ensured a comprehensive review of miR-21's multifaceted role in pancreatic cancers. In this review, we explore the current understandings and future directions regarding the regulation, diagnostic, prognostic, and therapeutic potential of targeting miR-21 in PDAC. This exhaustive review discusses the involvement of miR-21 in proliferation, epithelial-mesenchymal transition (EMT), apoptosis modulation, angiogenesis, and its role in therapy resistance. Also discussed in the review is the interplay between various molecular pathways that contribute to tumor progression, with specific reference to pancreatic ductal adenocarcinoma.

A miRNA-21-Mediated PTEN/Akt/NF-κB Axis Promotes Chronic Obstructive Pulmonary Disease Pathogenesis.

This study sought to explore the underlying mechanism of miR-21 mediated apoptosis and inflammation in chronic obstructive pulmonary disease (COPD) induced by cigarette smoke (CS). We detected levels and PTEN/Akt/NF-κB axis protein levels in peripheral lung tissues of COPD patients and CS-exposed mice and HBE cells. Western blotting assay was used to determine the expression of cleaved caspase-3. IL-6 and IL-8 protein was detected in cell supernatant from cells by ELISA. HBE cells were transfected with a miR-21 inhibitor, and co-culture with A549. Increased miR-21 expression, reduced PTEN expression and following activation of Akt in in peripheral lung tissues of COPD patients and CS-exposed mice and HBE cells. Inhibition of miR-21 showed enhanced PTEN levels and reduced the expression of phosphorylated form of Akt and NF-κB. Decreased expression of cleaved caspase-3, IL-6 and IL-8 in A549 cells co cultured with HBE cells transfected with miR-21 inhibitor compared with transfected with miR-21 control inhibitor. MiR-21 contributes to COPD pathogenesis by modulating apoptosis and inflammation through the PTEN/Akt/NF-κB pathway. Targeting miR-21 may increase PTEN expression and inhibit Akt/NF-κB pathway, offering potential diagnostic and therapeutic value in COPD management.

Abstract 2907: Therapeutic targeting miR-146a and miR-21 induce malignant cell death and regulate CD8+ T-cell function in mycosis fungoides with large-cell transformation

Abstract Large cell transformation of mycosis fungoides (LCT-MF) occurs in 20-50% of advanced MF and is associated with an aggressive clinical course and poor survival not to overcome by any standard treatment regimen. We have previously identified a distinct miRNA expression profile in LCT-MF from that of non-transformed MF with significant upregulation of miR-21 and miR-146a. Our analyses demonstrated the involvement of genes for immune checkpoint pathways such as ICOS-ICOSL and PD1-PDL1 signaling (Di Raimondo C et al. Cancers 2021). Here, we aimed to investigate the efficacy of antagomiR-146a and -21 (amiR-146a, and -21) on the tumor growth and CD8+ tumor infiltrating lymphocyte exhaustion in LCT-MF. The amiR-146a, and -21 were synthesized in our DNA/RNA Synthesis Core by linking CpG-D19. In vitro, CTCL cell lines (Myla and HH) were treated with amiR-146a and -21, the cell viability was assessed by the 2,5-diphenyl-2H-tetrazolium bromide assay and cell apoptosis was evaluated using apoptosis assay. We found that amiR-146a, and -21 synergistically inhibited the proliferation of MyLa and HH cells due to the activation of apoptosis through Caspase3/7 pathways and inducing cell cycle arrest by blocking STAT3/CDK1/Cyclin B1 pathway. Our RNA-seq data indicated that the exhausted CD8+ T cells express elevated amounts of STAT3, IRF4, and BATF in LCT-MF compared with non-LCT MF. To evaluate the functional importance of amiR-146a, and -21 on CD8+ T cell exhaustion, we induced an exhausted state of CD8+ T cells with high level of immune checkpoints and dysfunctional cytokine production by continues anti-CD3/DC28 beads and culture supernatant (MyLa or HH cell) exposure. Our data revealed that amiR-146a and -21 attenuated the CD8+ T cell exhaustion by blockade of immune checkpoints and STAT3/IRF4/BATF pathway to trigger the cytotoxic immune response. Collectively, the findings of our study suggest that targeting miR-146a and -21 is a promising and novel therapeutic strategy for LCT-MF. Citation Format: Zhen Han, Piotr Swiderski, Xiwei Wu, Yate-Ching Yuan, Jun Wu, Chingyu Su, Hanjun Qin, Steven Rosen, Christiane Querfeld. Therapeutic targeting miR-146a and miR-21 induce malignant cell death and regulate CD8+ T-cell function in mycosis fungoides with large-cell transformation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2907.

Targeting miR-21 to Overcome P-glycoprotein Drug Efflux in Doxorubicin-Resistant 4T1 Breast Cancer.

Acquired resistance to chemotherapy is a major challenge in the treatment of triple-negative breast cancer (TNBC). Despite accumulated evidence showing microRNA-21 (miR-21) as a vital regulator of tumor progression, the role of miR-21 in modulating the multidrug resistance of TNBC remains obscure. In this study, we demonstrate that miR-21 affects chemoresistance in 4T1 TNBC cells in response to doxorubicin (DOX) by regulating the P-glycoprotein (P-gp) drug efflux pump. Overexpression of miR-21 in the 4T1 cells markedly reduced their sensitivity to DOX, impeding DOX-promoted cell death. We employed anti-miR-21 oligonucleotide conjugated with a PD-L1-binding peptide (P21) for targeted delivery to 4T1 tumor cells. The selective down-regulation of miR-21 in 4T1 TNBC led to the reversal of P-gp-mediated DOX resistance by up-regulating phosphatase and tensin homolog (PTEN). Our study highlights that miR-21 is a key regulator of drug efflux pumps in TNBC, and targeting miR-21 could enhance DOX sensitivity, offering a potential therapeutic option for patients with DOX-resistant TNBC.

Rapid Colorimetric Determination of microRNA (miRNA) Using an Autocatalytic Entropy-Driven Circuit (AEDC)

A colorimetric and rapid signal amplified microRNA (miRNA) detection system based on autocatalytic entropy-driven circuit (AEDC) is reported. The target miRNA-21 (miR-21) was firstly hybridized with the sticky end of the triple-stranded hybrid complex (S, which consisting of a reporter strand (P), a byproduct strand (R) and an assistant strand (Q)), and P strand, which contained the G-quadruplex sequence that was released through the toehold-mediated strand displacement reaction. The G-quadruplex sequence interacted with hemin to form the peroxidase-mimicking DNAzymes and catalyzed the H2O2-mediated oxidation of colorless 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS2−) to the green ABTS•−. Meanwhile, fuel strand (F) hybridized with S to release the target miR-21 and the waste duplex DNA product F-Q was formed, which brings the two split mimic target DNA sequences into proximity to form the intact mimic target DNA sequence (analogue of miR-21). The obtained mimic target DNA as well as the released miR-21 can be cyclically used to trigger autocatalytic EDC reaction, leading to the rapidly enhanced formation of mimic target DNA with the concomitant generation of a higher colorimetric signal. Finally, a colorimetric and rapid miR-21 system based on the hairpin-free AEDC reaction was successfully fabricated. This system also has been applied for the miRNA determination in serum, exhibiting the potential application in the clinical diagnosis.

Dual-signal SERS biosensor based on spindle-shaped gold array for sensitive and accurate detection of miRNA 21

MicroRNAs (miRNAs) play an important regulatory role in tumor progression and have been emerging as promising biomarkers for early diagnosis of breast cancer. Herein, we developed a dual-signal surface-enhanced Raman scattering (SERS) biosensor for the quantitative detection of miRNA 21 (miR-21) by utilizing a tightly ordered spindle-shaped gold (SAu) array with 5, 5′-dithio-bis-(2-nitrobenzoic acid) (DTNB) molecule as an internal standard. Meanwhile, 6-carboxyl-Xrhodamine (ROX) labeled hairpin DNA H1 was linked to the SAu array by Au–S bonds generating another SERS signal. In the presence of miR-21, H1 was turned on with a decrease in SERS signal of ROX, while the SERS signal of DTNB remained stable. The SAu array as substrate provides a large area of hot spots, and the dual-signal can avoid background interference and achieve signal self-calibration. By the dual-signal SERS biosensor, target miR-21 could be detected over a broad linear range (0.1 −105 pM) with a low detection limit (0.046 pM) without signal amplification strategy. Thanks to the SAu array and dual-signal output, the sensor showed high sensitivity, good signal reproducibility, excellent specificity, and high detection accuracy. When this sensor was applied to the miR-21 assay in human serum samples, its performance was comparable to quantitative reverse transcription polymerase chain reaction (qRT-PCR), indicating promising applications of the developed sensor for cancer diagnostics.

Abstract A174: Antitumor activity of lipid nanoparticle-delivered anti-miR-21

Abstract Background: MicroRNAs (miRNAs) are small non-coding RNA molecules that play crucial roles in various biological processes, such as growth, development, aging, and apoptosis. Several studies have shown that miRNAs, including miR-21, can function as either oncogenes or tumor suppressor genes, influencing tumor initiation and progression. Aberrant expression of miR-21 has been observed in different cancer cells, indicating its significant involvement as an oncogenic miRNA in the development of various types of tumors. Antisense oligonucleotides (ASOs) have been identified as effective tools for downregulating target genes by either triggering RNase H endonuclease activity to cleave the ASO-target gene heteroduplex or by interfering with splicing and translation regulation of the target RNA sequence. ASOs have the potential to target not only mRNA but also oligonucleotides like miRNAs or small interfering RNAs (siRNAs), making them a promising approach for miRNA inhibition. However, the efficient delivery of freely circulating ASOs to the tumor microenvironment poses a challenge due to their high density of negative charges, impeding cell uptake. To address this issue, a novel lipid nanoparticle (LNP) platform called QTsome has been developed, which combines quaternary amine cationic lipids and tertiary amine ionizable lipids to enhance drug delivery. The utilization of a mixture of cationic and ionizable lipids in QTsome allows for optimal pH-dependent drug loading and release characteristics. In this study, our objective was to employ the QTsome system to deliver an ASO targeting miR-21 (AM-21) for potential tumor therapy. Methods: A total of 8E6 A549 cells were inoculated into mice, and when the tumor volume reached 100mm3, the mice were randomly divided into seven groups based on tumor volume, with each group consisting of five mice.On the day of grouping, drug administration was initiated with the following doses: 1mg/kg, every 3 days (Q3D); 2mg/kg, Q3D; 3mg/kg, Q3D; 4mg/kg, Q3D; 4mg/kg, every 4 days (Q4D); 4mg/kg, every 5 days (Q5D); 4mg/kg, every 7 days (Q7D). The drugs were administered a total of 5 times. Additionally, the A549/MC38 model was constructed using the same method. The antitumor activity of the drug and its therapeutic effect in combination with Erlotinib were evaluated in both the A549 CDX and MC38 syngeneic mouse models through intravenous injection, with a dose of 4mg/kg, Q3D. Results: The study revealed that the optimal dose for achieving the maximum antitumor effect was 4mg/kg, administered 3 times per day. In the A549 model, the tumor growth inhibition rates were 71.91%, 60.93%, and 80.44% for the AM-21/QTsome group, Erlotinib group, and the combination of AM-21/QTsome and Erlotinib group, respectively. In the MC38 mouse model, the tumor inhibition rate of AM-21/QTsome was 33.29%. Conclusion: These results emphasize the potential of miR-21 as a therapeutic target for cancer treatment, demonstrating that AM-21/QTsome holds great promise as a groundbreaking drug in this field. Citation Format: Jing Li, Qiaofang Ma, Xinyue Zhang, Xiaojie Chen, Jialiang Lin, Jun Bai, Fei Su, Xiaobin Zhao, Robert J. Lee, Yongsheng Yang. Antitumor activity of lipid nanoparticle-delivered anti-miR-21 [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A174.

EXTH-55. ALL-IN-ONE GENETIC CONSTRUCT TO KNOCKDOWN MIR-21 REDUCES GLIOMA PROLIFERATION IN VITRO

Abstract Glioma, the most aggressive tumor of the CNS has poor patient outcome with limited effective treatments. CRISPR-CAS technology recently opened a new avenue for gene therapy and has been previously used to target non-coding RNAs, including microRNA-21, an oncogene associated with glioma progression. Here we show that an all-in-one construct containing both Staphylococcus Aureus Cas9 (SaCas9) guided by a single-guide RNA (sgRNA) specifically targeting miR-21 resulted in a deletion causing a downregulation of miR-21 expression levels and reduced proliferation in glioma cell lines. Here, we aim to design a single adeno-associated vector (rAAV) vector platform that express both saCas9 and sgRNA to target miR-21 in a glioma syngeneic mouse model. With the future goal to engineer a single AAV that can achieve therapeutic genome editing outcomes.

MicroRNA-21 Silencing in Diabetic Nephropathy: Insights on Therapeutic Strategies.

In diabetes, possibly the most significant site of microvascular damage is the kidney. Due to diabetes and/or other co-morbidities, such as hypertension and age-related nephron loss, a significant number of people with diabetes suffer from kidney diseases. Improved diabetic care can reduce the prevalence of diabetic nephropathy (DN); however, innovative treatment approaches are still required. MicroRNA-21 (miR-21) is one of the most studied multipotent microRNAs (miRNAs), and it has been linked to renal fibrosis and exhibits significantly altered expression in DN. Targeting miR-21 offers an advantage in DN. Currently, miR-21 is being pharmacologically silenced through various methods, all of which are in early development. In this review, we summarize the role of miR-21 in the molecular pathogenesis of DN and several therapeutic strategies to use miR-21 as a therapeutic target in DN. The existing experimental interventions offer a way to rectify the lower miRNA levels as well as to reduce the higher levels. Synthetic miRNAs also referred to as miR-mimics, can compensate for abnormally low miRNA levels. Furthermore, strategies like oligonucleotides can be used to alter the miRNA levels. It is reasonable to target miR-21 for improved results because it directly contributes to the pathological processes of kidney diseases, including DN.

Electroacupuncture Promotes Nerve Regeneration and Functional Recovery Through Regulating lncRNA GAS5 Targeting miR-21 After Sciatic Nerve Injury

Although the benefits of electroacupuncture (EA) for peripheral nerve injury (PNI) are well accepted in clinical practice, the underlying mechanism remains incompletely elucidated. In our study, we observed that EA intervention led to a reduction in the expression of the long non-coding RNA growth-arrest-specific transcript 5 (GAS5) and an increased in miR-21 levels within the injured nerve, effectively promoting functional recovery and nerve regeneration following sciatic nerve injury (SNI). In contrast, administration of adeno-associated virus expressing GAS5 (AAV-GAS5) weakened the therapeutic effect of EA. On the other hand, both silencing GAS5 and introducing a miR-21 mimic prominently enhanced the proliferation activity and migration ability of Schwann cells (SCs), while also inhibiting SCs apoptosis. On the contrary, inhibition of SCs apoptosis was found to be mediated by miR-21. Additionally, overexpression of GAS5 counteracted the effects of the miR-21 mimic on SCs. Moreover, SCs that transfected with the miR-21 mimic promoted neurite growth in hypoxia/reoxygenation-induced neurons, which might be prevented by overexpressing GAS5. Furthermore, GAS5 was found to be widely distributed in the cytoplasm and was negatively regulated by miR-21. Consequently, the targeting of GAS5 by miR-21 represents a potential mechanism through which EA enhances reinnervation and functional restoration following SNI. Mechanistically, the GAS5/miR-21 axis can modulate the proliferation, migration, and apoptosis of SCs while potentially influencing the neurite growth of neurons.

DUSP1 regulates the JAK2/STAT3 signaling pathway through targeting miR-21 in cervical cancer cells.

This study was to investigate the effect of DUSP1 on cervical cancer (CC) cells by targeting the miR-21 regulatory JAK2/STAT3 signaling pathway. For this purpose, fifteen CC patients treated at our hospital from January 2021 to February 2023 were selected. CC tissues and para-cancerous (PC) tissues were collected from the patients, and DUSP1 protein and mRNA expression levels were detected by Western blot and qPCR. The C33a control group (COG) and DUSP1 overexpression group (OVG) were set up: human cervical squamous carcinoma cells (CSCC) in the C33a COG were cultured without any treatment, while the DUSP1 OVG was cultured using DUSP1 gene overexpression lentivirus infection progeny. The proliferation ability of the three groups of cells was measured by CCK8, protein and mRNA expression by Western blot and qPCR, and cell migration and invasion ability by Transwell. It was found that DUSP1 protein and mRNA in CC tissues were reduced compared with those in PC tissues (P<0.05). The miR-21 in the DUSP1 OVG was reduced than those in the C33a COG (P<0.05). The expression of JAK2, STAT3 mRNA and protein in the DUSP1 OVG were reduced compared with those in the C33a COG (P<0.05). In conclusion, overexpression of DUSP1 can target and reduce the expression of miR-21, block the JAK2/STAT3 signaling pathway, reduce the viability of CC cells, inhibit the proliferation and migration and invasion ability of CC cells, and induce apoptosis of CC cells, thus providing a theoretical basis for the targeted treatment of clinical CC.

CRISPR-empowered electrochemical biosensor for target amplification-free and sensitive detection of miRNA

The clustered regularly interspaced short palindromic repeats (CRISPR) system provides a new molecular diagnostic tool for construction of biosensor platforms due to its high programmability and target specificity. Herein, we developed a CRISPR-empowered electrochemical biosensor by combining the advantages of CRISPR/Cas13a and primer exchange reaction (PER), named PER-E-CRISPR, for target amplification-free and sensitive detection of miR-21. Dual-signal amplification procedures involve the binding of target miR-21 induced by CRISPR-based amplification, along with the hybridization of multiple short single-stranded DNA strands with PER concatemers. When target miR-21 is present, CRISPR/Cas13a specifically recognizes the target miRNA, triggering the trans-cleavage activity of CRISPR/Cas13a. Then Cas13a/crRNA/miRNA cleaved the predesigned ribonucleotide site in hairpin 1 (HP1) and released trigger to open hairpin 2 (HP2) modified on the electrode surface. Then PER bridge sequence contained in HP2 is exposed and hybridized with PER concatemers, following multiple short single-stranded DNA tagged with methylene blue (ssDNA-MB) bond with the PER concatemers. Under optimized conditions, PER-E-CRISPR assay for detecting miR-21 exhibits linearity in dynamic range from 10−13 to 10−7 M, and we obtained a limit of detection (LOD) of 30.2 fM. The established PER-E-CRISPR biosensor shows perfect practical performance in actual plasma, which may have great promising prospects for miRNA detection in the field of molecular diagnosis.

The Critical Role of microRNA-21 in Non-alcoholic Fatty Liver Disease Pathogenesis.

Nonalcoholic fatty liver disease (NAFLD) has received worldwide scientific attention because of its rapidly increasing prevalence, and it has emerged as a serious public health problem in end-stage liver disease. Many factors are involved in the multifactorial development and progression of liver disease by influencing multiple signaling and metabolic pathways. Currently, many studies have demonstrated the critical role of microRNA- 21 (miR-21) in NAFLD pathogenesis. In addition, many studies have found that miR-21 is highly expressed in inflammatory bowel disease, which is associated with intestinal barrier dysfunction and altered gut microbiota. In this paper, we focus on the regulatory role of miR-21 in the progression of NAFLD and its effect on the gut microbiota, summarize the involvement of miR-21 through a variety of signaling pathways and metabolic pathways, as well as discuss some predicted miR-21 target genes and miR-21 pathways for future experimental identification.

Photocurrent-Polarity-Switching Photoelectrochemical Biosensor for Switching Spatial Distance Electroactive Tags.

This work presents a photocurrent-polarity-switching-based photoelectrochemical (PEC) biosensing platform for ultrasensitive detection of microRNA-21 (miR-21) through target-triggered catalytic hairpin assembly (CHA) for modulation of methylene blue (MB) and ferrocene (Fc) positional configurations using double-shelled Cu-doped ZnS nanocages (NCs)-Au nanoparticles (NPs) as photoactive materials. In the presence of miR-21, the assembly of MB-labeled HP1 and Fc-labeled HP2 leads to the generation of a large amount of double-stranded DNA (HP1-HP2), which pushes MB away from the electrode surface and brings Fc close to the electrode surface, resulting in effectively quenching the enhanced PEC signal to activate the photocurrent-polarity-switching system. Benefiting from the distance-controllable strategy, the designed PEC bioanalysis can effectively eliminate false-positive and false-negative signals due to the change of different signal expression patterns (from traditional the "signal-on" mode to the photocurrent-polarity-switching mode), thereby significantly improving the sensing specificity and sensitivity. The proposed PEC sensing system exhibited satisfying photocurrent responses toward target miR-21 within the working range from 1.0 fM to 1 nM at a low limit of detection (LOD) of 0.58 fM. More importantly, we demonstrated the successful integration of the proposed PEC biosensor with a handheld wireless device for instant detection of miR-21 concentrations in practical samples.