microRNA-induced translational control of antiviral immunity by the cap-binding protein 4EHP.

Type I interferons (IFNs) are critical cytokines in the host defense against invading pathogens. Sustained production of IFNs, however, is detrimental to the host, as it provokes autoimmune diseases. Thus, the expression of IFNs is tightly controlled. We report that the mRNA 5' cap-binding protein 4EHP plays a key role in regulating type I IFN concomitant with controlling virus replication, both in vitro and in vivo. Mechanistically, 4EHP suppresses IFN-ß production by effecting the miR-34a-induced translational silencing of Ifnb1 mRNA. miR-34a is upregulated by both RNA virus infection and IFN-ß induction, prompting a negative feedback regulatory mechanism that represses IFN-ß expression via 4EHP. These findings demonstrate the direct involvement of 4EHP in virus-induced host response, underscoring a critical translational silencing mechanism mediated by 4EHP and miR-34a to impede sustained IFN production. This study highlights an intrinsic regulatory function for miRNA and the translation machinery in maintaining host homeostasis.

Epimedium-Curculigo herb pair enhances bone repair with infected bone defects and regulates osteoblasts through LncRNA MALAT1/miR-34a-5p/SMAD2 axis.

Infected bone defects (IBDs) are the common condition in the clinical practice of orthopaedics. Although surgery and anti-infective medicine are the firstly chosen treatments, in many cases, patients experience a prolonged bone union process after anti-infective treatment. Epimedium-Curculigo herb pair (ECP) has been proved to be effective for bone repair. However, the mechanisms of ECP in IBDs are insufficiency. In this study, Effect of ECP in IBDs was verified by micro-CT and histological examination. Qualitative and quantitative analysis of the main components in ECP containing medicated serum (ECP-CS) were performed. The network pharmacological approaches were then applied to predict potential pathways for ECP associated with bone repair. In addition, the mechanism of ECP regulating LncRNA MALAT1/miRNA-34a-5p/SMAD2 signalling axis was evaluated by molecular biology experiments. In vivo experiments indicated that ECP could significantly promote bone repair. The results of the chemical components analysis and the pathway identification revealed that TGF-ß signalling pathway was related to ECP. The results of in vitro experiments indicated that ECP-CS could reverse the damage caused by LPS through inhibiting the expressions of LncRNA MALAT1 and SMAD2, and improving the expressions of miR-34a-5p, ALP, RUNX2 and Collagen type І in osteoblasts significantly. This research showed that ECP could regulate the TGF-ß/SMADs signalling pathway to promote bone repair. Meanwhile, ECP could alleviate LPS-induced bone loss by modulating the signalling axis of LncRNA MALAT1/miRNA-34a-5p/ SMAD2 in IBDs.

Protective effect of dimethyl fumarate against ethanol-provoked gastric ulcers in rats via regulation of HMGB1/TLR4/NF-κB, and PPARγ/SIRT1/Nrf2 pathways: Involvement of miR-34a-5p.

Aberration of the gastric mucosal barrier homeostasis circuit is one of the key features linked to the onset of gastric ulcers (GU). This work aimed to inspect the gastroprotective influence of dimethyl fumarate (DMF) on ethanol-induced GU in rats and to decipher the possible mechanisms entailed. Rats were pretreated with either DMF (80 mg/kg) or omeprazole (OMP) (20 mg/kg) by oral gavage for 2 weeks. After 24 h of starvation, ethanol (5 ml/kg, oral) was employed to trigger GU in rats, while carboxymethyl cellulose (CMC) was used as a control. Ethanol notably elevated both macroscopic and microscopic gastric damage. DMF and OMP exhibited similar effects on gastric ulcer healing. DMF intervention led to a substantial improvement in gastric insults. DMF significantly reduced ethanol-triggered gastric lesions, as manifested by decreased gastric secretion, acidity, ulcer surface area percent, reduced leukocyte incursion, and increased mucus percent. DMF upregulated miR-34a-5p expression concomitant with the suppression of high mobility group box1 (HMGB1) and inflammatory responses in gastric mucosal homogenate. DMF improved GU by restoring reduced antioxidant defense mechanisms through the coactivation of nuclear factor erythroid 2-related factor-2 (Nrf2), peroxisome proliferator-activated receptor gamma (PPARγ), and sirtuin1 (SIRT1), indicating the protective role of the PPARγ/SIRT1/Nrf2 pathway. Intriguingly, DMF mitigated apoptosis in ethanol-elicited GU. Taken together, this research implies the potential for the repurposing of DMF as an innovative gastroprotective medication to reestablish the balance of the gastric mucosal barrier via the attenuation of gastric inflammation, oxidative stress, and apoptosis.

MiR-34a promotes mitochondrial pathway of apoptosis in human salivary gland epithelial cells by activating NF-κB signaling.

To investigate the potential molecular mechanism of miR-34a in Sjögren's syndrome (SS). Transmission electron microscopy was used to observe the salivary gland tissues of mild and severe SS patients. SS mouse model was constructed and injected with miR-34a antagonist. HSGE cells were transfected with miR-34a mimic. Starbase predicted miR-34a binding sites and validated them with dual-luciferase reporter assays. Immunohistochemistry, HE staining, CCK-8, TUNEL assay, flow cytometry, immunofluorescence and Western Blot were used to investigate the effects of miR-34a on NF-κB signaling and mitochondrial pathway of apoptosis in HSGE cells. Severe SS patients showed obvious mitochondrial damage and apoptosis in salivary glands. MiR-34a was overexpressed and NF-κB signaling is activated in salivary glands of severe SS patients. Inhibition of miR-34a alleviated salivary gland injury in SS mice, as well as inhibited the activation of NF-κB signaling and mitochondrial pathway of apoptosis. In conclusion, miR-34a promoted NF-κB signaling by targeting IκBα, thereby causing mitochondrial pathway apoptosis and aggravating SS-induced salivary gland damage.

Kupffer cell pyroptosis mediated by METTL3 contributes to the progression of alcoholic steatohepatitis.

Chronic alcohol consumption is a major risk factor for alcoholic steatohepatitis (ASH). Previous studies have shown that direct injury of hepatocytes is the key factor in its occurrence and development. However, our study shows that the role of Kupffer cells in ASH cannot be ignored. We isolated Kupffer cells from the livers of ASH mice and found that alcohol consumption induced Kupffer cell pyroptosis and increased the release of interleukin-1ß (IL-1ß). Furthermore, we screened the related m6A enzyme methyltransferase-like 3 (METTL3) from liver Kupffer cells, and found that silencing METTL3 alleviated inflammatory cytokine eruption by Kupffer cell pyroptosis in ASH mice. In vitro, we silenced METTL3 with lentivirus in BMDMs and RAW264.7 cells and confirmed that METTL3 could reduce pyroptosis by influencing the splicing of pri-miR-34A. Together, our results revealed a critical role of KC pyroptosis in ASH and highlighted the mechanism by which METLL3 relieves cell pyroptosis, which could be a promising therapeutic strategy for ASH.

Ionizing radiation effects on blood-derived extracellular vesicles: insights into miR-34a-5p-mediated cellular responses and biomarker potential.

Adverse effects of ionizing radiation on normal tissues limit the radiation dose in cancer treatment, thereby compromising treatment efficiency. Among the consistently affected non-cancer cells, peripheral blood mononuclear cells (PBMCs) exhibit high radiosensitivity and have the potential to induce systemic effects. PBMC-released extracellular vesicles (EVs), contribute to the communication of such systemic effects. This study aimed to investigate the effects of ionizing radiation on EVs as part of the systemic response of PBMCs in terms of microRNA cargo and biological functions.Therefore, whole blood samples from healthy donors were irradiated ex-vivo (0 Gy, 1 Gy, 2 Gy, 4 Gy) and EVs from PBMCs were isolated after 96 h by PEG precipitation or ultracentrifugation. Candidate microRNAs were examined in PBMC-derived EVs from individual donors. The uptake of membrane-stained fluorescent EVs by different recipient cells was quantified by fluorescence-activated cell sorting analysis. The biological effects of increased miR-34a-5p and of total EVs on recipient cells were assessed.Irradiation of PBMCs induced a dose-dependent upregulation of miR-34a-5p within EVs and PBMCs. However, interindividual differences between donors were noticed in the extent of upregulation, and small EVs displayed more pronounced changes in microRNA levels in comparison to large EVs. Irradiation in presence of the small molecule inhibitor KU-60019 demonstrated that this upregulation is dependent on ATM (Ataxia telangiectasia mutated) activation. Moreover, fibroblasts and keratinocytes were identified as preferred EV recipients. Increased miR-34a-5p levels led to a significant reduction in viability and induction of senescence in keratinocytes but not in fibroblasts, indicating a cell type-specific response.In conclusion, this study further elucidated the complex cellular response of normal tissue after radiation exposure. It confirmed radiation-induced modifications of microRNA expression levels in EVs from PBMCs and identified a robust upregulation of miR-34a-5p in the small EV subfraction, suggesting this microRNA as a potential novel candidate for the development of biomarkers for radiation exposure. Moreover, the different uptake efficiencies observed among specific cell types suggested that EVs induce cell type-specific responses in the intercellular communication of systemic radiation effects.

The Impact of miR-34a on Endothelial Cell Viability and Apoptosis in Ischemic Stroke: Unraveling the MTHFR-Homocysteine Pathway.

INTRODUCTION: Ischemic stroke (IS) is a global health concern, often tied to dyslipidemia and vascular endothelial dysfunction. MicroRNA-34a (miR-34a) was reported to be up-regulated in the blood samples of patients with IS, but the specific role of miR-34a and methylenetetrahydrofolate reductase (MTHFR) in IS remains to be elucidated. METHODS: We studied 143 subjects: 71 IS patients, and 72 healthy controls. Human umbilical vein endothelial cells (HUVECs) were cultured and transfected with a miR-34a mimic, inhibitor, or negative control. The miR-34a expression in serum and HUVECs was quantified via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Viability and apoptosis of HUVECs were assessed using CCK-8 assay and flow cytometry. The expression levels of bcl-2, bax, cyt-c, cleaved caspase 3, MTHFR, and homocysteine were measured by Western blot or enzyme-linked immunosorbent assay (ELISA). The relationship between miR-34a and MTHFR was verified by luciferase reporter assay. The levels of MTHFR and homocysteine in serum were examined by ELISA. RESULTS: MiR-34a expression was increased in IS patients and inhibited viability of HUVECs while promoting their apoptosis. Overexpression of miR-34a up-regulated pro-apoptotic proteins (bax, cyt-c and cleaved caspase 3) and down-regulated anti-apoptotic protein bcl-2 in HUVECs. MTHFR was identified as the downstream target of miR-34a and its expression was reduced by miR-34a overexpression, while homocysteine levels increased. Consistently, MTHFR levels were lower and homocysteine levels were higher in IS patients compared with controls. DISCUSSION: Our results suggest that up-regulated miR-34a plays a role in the pathogenesis of IS, potentially through inhibiting MTHFR expression and increasing homocysteine in endothelial cells. Therefore, miR-34a might be a therapeutic target for IS.

MicroRNA as Key Players in Hepatocellular Carcinoma: Insights into Their Role in Metastasis.

Liver cancer or hepatocellular carcinoma (HCC) remains the most common cancer in global epidemiology. Both the frequency and fatality of this malignancy have shown an upward trend over recent decades. Liver cancer is a significant concern due to its propensity for both intrahepatic and extrahepatic metastasis. Liver cancer metastasis is a multifaceted process characterized by cell detachment from the bulk tumor, modulation of cellular motility and invasiveness, enhanced proliferation, avoidance of the immune system, and spread either via lymphatic or blood vessels. MicroRNAs (miRNAs) are small non-coding ribonucleic acids (RNAs) playing a crucial function in the intricate mechanisms of tumor metastasis. A number of miRNAs can either increase or reduce metastasis via several mechanisms, such as control of motility, proliferation, attack by the immune system, cancer stem cell properties, altering the microenvironment, and the epithelial-mesenchymal transition (EMT). Besides, two other types of non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) can competitively bind to endogenous miRNAs. This competition results in the impaired ability of the miRNAs to inhibit the expression of the specific messenger RNAs (mRNAs) that are targeted. Increasing evidence has shown that the regulatory axis comprising circRNA/lncRNA-miRNA-mRNA is correlated with the regulation of HCC metastasis. This review seeks to present a thorough summary of recent research on miRNAs in HCC, and their roles in the cellular processes of EMT, invasion and migration, as well as the metastasis of malignant cells. Finally, we discuss the function of the lncRNA/circRNA-miRNA-mRNA network as a crucial modulator of carcinogenesis and the regulation of signaling pathways or genes that are relevant to the metastasis of HCC. These findings have the potential to offer valuable insight into the discovery of novel therapeutic approaches for management of liver cancer metastasis.

Evaluating the Serum Level of ACTH and Investigating the Expression of miR-26a, miR-34a, miR-155-5p, and miR-146a in the Peripheral Blood Cells of Multiple Sclerosis Patients.

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disorder affecting white and gray matter. This study aimed to investigate the association between clinical outcomes in MS patients and the levels of certain molecules in their serum, including ACTH, IL-17, and specific miRNAs: miR-26a, miR-34a, miR-155-5p, and miR-146a. Fifty healthy people and 75 blood samples from MS patients were selected. MS patients had higher expression levels of IL-17, miR-26a, miR-34a, and miR-146a compared to healthy individuals (p < 0.0001). There was no significant difference in miR-155-5p expression between the two groups (p = 0.203). MS patients also had higher serum levels of ACTH compared to the normal population (p < 0.0001). In MS patients, there was a negative correlation between IL-17 and miR-155-5p expression levels (p = 0.048, r = - 0.229). Similarly, a significant negative correlation was observed between ACTH and miR-155-5p in the control group (p = 0.044, r = - 0.286). The study's analysis revealed no significant difference in the expression of miR-155-5p between MS patients and normal individuals; the study's examination revealed that the expression level of IL-17, miR-26a, miR-34a, and miR-146a was higher in MS patients than in normal individuals.

LincRNA-EPS Promotes Proliferation of Aged Dermal Fibroblast by Inducing CCND1.

The aging process is linked to numerous cellular changes, among which are modifications in the functionality of dermal fibroblasts. These fibroblasts play a crucial role in sustaining the healing of skin wounds. Reduced cell proliferation is a hallmark feature of aged dermal fibroblasts. Long intergenic non-coding RNA (lincRNAs), such as LincRNA-EPS (Erythroid ProSurvival), has been implicated in various cellular processes. However, its role in aged dermal fibroblasts and its impact on the cell cycle and its regulator, Cyclin D1 (CCND1), remains unclear. Primary dermal fibroblasts were isolated from the skin of 17-week-old (young) and 88-week-old (aged) mice. Overexpression of LincRNA-EPS was achieved through plasmid transfection. Cell proliferation was detected using the MTT assay. Real-time PCR was used to quantify relative gene expressions. Our findings indicate a noteworthy decline in the expression of LincRNA-EPS in aged dermal fibroblasts, accompanied by reduced levels of CCND1 and diminished cell proliferation in these aging cells. Significantly, the overexpression of LincRNA-EPS in aged dermal fibroblasts resulted in an upregulation of CCND1 expression and a substantial increase in cell proliferation. Mechanistically, LincRNA-EPS induces CCND1 expression by sequestering miR-34a, which was dysregulated in aged dermal fibroblasts, and directly targeting CCND1. These outcomes underscore the crucial role of LincRNA-EPS in regulating CCND1 and promoting cell proliferation in aged dermal fibroblasts. Our study provides novel insights into the molecular mechanisms underlying age-related changes in dermal fibroblasts and their implications for skin wound healing. The significant reduction in LincRNA-EPS expression in aged dermal fibroblasts and its ability to induce CCND1 expression and enhance cell proliferation highlight its potential as a therapeutic target for addressing age-related skin wound healing.

Folate-Targeted Nanocarriers Co-Deliver Ganciclovir and miR-34a-5p for Combined Anti-KSHV Therapy.

Kaposi's sarcoma-associated herpesvirus (KSHV) can cause a variety of malignancies. Ganciclovir (GCV) is one of the most efficient drugs against KSHV, but its non-specificity can cause other side effects in patients. Nucleic acid miR-34a-5p can inhibit the transcription of KSHV RNA and has great potential in anti-KSHV therapy, but there are still problems such as easy degradation and low delivery efficiency. Here, we constructed a co-loaded dual-drug nanocomplex (GCV@ZIF-8/PEI-FA+miR-34a-5p) that contains GCV internally and adsorbs miR-34a-5p externally. The folic acid (FA)-coupled polyethyleneimine (PEI) coating layer (PEI-FA) was shown to increase the cellular uptake of the nanocomplex, which is conducive to the enrichment of drugs at the KSHV infection site. GCV and miR-34a-5p are released at the site of the KSHV infection through the acid hydrolysis characteristics of ZIF-8 and the "proton sponge effect" of PEI. The co-loaded dual-drug nanocomplex not only inhibits the proliferation and migration of KSHV-positive cells but also decreases the mRNA expression level of KSHV lytic and latent genes. In conclusion, this co-loaded dual-drug nanocomplex may provide an attractive strategy for antiviral drug delivery and anti-KSHV therapy.

Expression of miR-34a, RASSF1A and E-cadherin in relation to PRB in endometrioid carcinoma and its precursor.

The current study aims to evaluate the levels of miR-34a, RASSF1A, and E-cadherin in relation to the levels of isoform B of progesterone receptor (PRB) in endometrioid carcinoma (EC) and atypical hyperplasia (AEH) and their association with clinicopathological parameters. 105 cases (35 EC, 35 AEH, and 35 control) were involved in this study. Cases of AEH received treatment, and other samples were obtained after 6 months to assess the response. E-cadherin and PRB were assessed by immunohistochemistry (IHC), RASSFA methylation by MSP-PCR, and its serum level by ELISA and miR-34a via quantitative PCR. The expressions of miR-34a, RASSF1A, E-cadherin, and PRB differ among the studied groups; all were higher in normal compared with AEH and EC, with a statistically significant difference. The higher PRB expression and decreased miR-34a and RASSF1A expression were associated with resistance to hormonal therapy in AEH. High PRB in EC is associated with lower RASSFA1, E-cadherin, and miR-34a. Decreased expressions of RASSF1A, miR-34a, and E-cadherin had a significant connection to advanced stages. Expression of PRB and miR-34a and serum levels of RASSF1A predict response to treatment in cases of AEH. High PRB and low E-cadherin expression are associated with progressive disease in EC.

Analysis of the regulatory role of miR-34a-5p/PLCD3 in the progression of osteoarthritis.

Osteoarthritis is a heterogeneous disease with a complex etiology. However, there is no effective treatment strategy at present. The purpose of this study was to explore the miRNA‒mRNA regulatory network and molecular mechanism that regulate the progression of osteoarthritis. In this article, we downloaded datasets (GSE55457, GSE82107, GSE143514 and GSE55235) from Gene Expression Omnibus (GEO) to screen differentially expressed mRNAs in osteoarthritis. Then, through weighted gene coexpression network (WGCNA), functional enrichment, protein‒protein interaction (PPI) network, miRNA‒mRNA coexpression network, ROC curve, and immune infiltration analyses and qPCR, the mRNA PLCD3, which was highly expressed in osteoarthritis and had clinical predictive value, was screened. We found that PLCD3 directly targets miR-34a-5p through DIANA and dual-luciferase experiments. The expression levels of PLCD3 and miR-34a-5p were negatively correlated. In addition, CCK-8 and wound healing assays showed that the miR-34a-5p mimic inhibited hFLS-OA cell proliferation and promoted hFLS-OA cell migration. PLCD3 overexpression showed the opposite trend. Western blotting further found that overexpression of miR-34a-5p reduced the protein expression levels of p-PI3K and p-AKT, while overexpression of PLCD3 showed the opposite trend. In addition, combined with the effect of the PI3K/AKT pathway inhibitor BIO (IC50 = 5.95 µM), the results showed that overexpression of miR-34a-5p increased the inhibitory effects of BIO on p-PI3K and p-AKT protein expression, while overexpression of PLCD3 significantly reversed these inhibitory effects. Overall, the miR-34a-5p/PLCD3 axis may mediate the PI3K/AKT pathway in regulating cartilage homeostasis in synovial osteoarthritis. These data indicate that miR-34a-5p/PLCD3 may be a new prognostic factor in the pathology of synovial osteoarthritis.

miR-34a-5p as molecular hub of pathomechanisms in Huntington's disease.

BACKGROUND: Although a pivotal role of microRNA (miRNA, miR) in the pathogenesis of Huntington's disease (HD) is increasingly recognized, the molecular functions of miRNAs in the pathomechanisms of HD await further elucidation. One of the miRNAs that have been associated with HD is miR-34a-5p, which was deregulated in the mouse R6/2 model and in human HD brain tissues. METHODS: The aim of our study was to demonstrate interactions between miR-34a-5p and HD associated genes. By computational means we predicted 12 801 potential target genes of miR-34a-5p. An in-silico pathway analysis revealed 22 potential miR-34a-5p target genes in the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway "Huntington's disease". RESULTS: Using our high-throughput miRNA interaction reporter assay (HiTmIR) we identified NDUFA9, TAF4B, NRF1, POLR2J2, DNALI1, HIP1, TGM2 and POLR2G as direct miR-34a-5p target genes. Direct binding of miR-34a-5p to target sites in the 3'UTRs of TAF4B, NDUFA9, HIP1 and NRF1 was verified by a mutagenesis HiTmIR assay and by determining endogenous protein levels for HIP1 and NDUFA9. STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) analysis identified protein-protein interaction networks associated with HD like "Glutamine Receptor Signaling Pathway" and "Calcium Ion Transmembrane Import Into Cytosol". CONCLUSION: Our study demonstrates multiple interactions between miR-34a-5p and HD associated target genes and thereby lays the ground for future therapeutic interventions using this miRNA.

circFANCA accelerates the malignant process of OSCC by modulating miR-34a/PA28γ signaling.

OBJECTIVES: To investigate the upstream regulatory molecules of proteasomal activator 28γ (PA28γ), and explore its specific regulatory mechanism and potential clinical significance in OSCC. MATERIALS AND METHODS: qPCR was used to examine miR-34a, circFANCA and PSME3 expression. Western blotting was adopted to detect PA28γ expression. Transwell experiments were conducted to evaluate OSCC cell migration and invasion ability. FISH was used to evaluate the subcellular localization of circFANCA and miR-34a, and RNA pull-down verified the interaction between them. The expression of circFANCA and miR-34a in clinical cohorts was assessed by ISH, and the results were subjected to survival analysis using Kaplan-Meier analysis. RESULTS: Here, we proved that miR-34a expression is lower in highly aggressive OSCC tissues and cell lines. Notably, miR-34a can downregulate PA28γ expression and inhibit OSCC invasion and migration. Next, we confirmed that circFANCA promoted OSCC cell metastatic ability by sponging miR-34a. Importantly, interfering with miR-34a rescued the malignant progression of OSCC induced by silencing circFANCA. Finally, clinical data showed lower miR-34a expression and higher circFANCA expression were associated with poor prognosis in OSCC patients. CONCLUSION: The circFANCA/miR-34a/PA28γ axis facilitates the metastasis of OSCC, and circFANCA and miR-34a have potential to serve as prognostic markers for OSCC patients.

Targeted therapy using nanocomposite delivery systems in cancer treatment: highlighting miR34a regulation for clinical applications.

The clinical application of microRNAs in modern therapeutics holds great promise to uncover molecular limitations and conquer the unbeatable castle of cancer metastasis. miRNAs play a decisive role that regulating gene expression at the post-transcription level while controlling both the stability and translation capacity of mRNAs. Specifically, miR34a is a master regulator of the tumor suppressor gene, cancer progression, stemness, and drug resistance at the cell level in p53-dependent and independent signaling. With changing, trends in nanotechnology, in particular with the revolution in the field of nanomedicine, nano drug delivery systems have emerged as a prominent strategy in clinical practices coupled with miR34a delivery. Recently, it has been observed that forced miR34a expression in human cancer cell lines and model organisms limits cell proliferation and metastasis by targeting several signaling cascades, with various studies endorsing that miR34a deregulation in cancer cells modulates apoptosis and thus requires targeted nano-delivery systems for cancer treatment. In this sense, the present review aims to provide an overview of the clinical applications of miR34a regulation in targeted therapy of cancer.

miR-34a-5p facilitates osteogenic differentiation of bone marrow mesenchymal stem cells and modulates bone metabolism by targeting HDAC1 and promoting ER-α transcription.

OBJECTIVE: Metabolism is essential for bone development. The expressions of catabolic markers in chondrocytes show association with miR-34a-5p. This study discussed the mechanism by which miR-34a-5p regulates osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) as well as bone metabolism. METHODS: Expressions of BMSC surface markers were determined via flow cytometry. Osteogenic differentiation of BMSCs was subsequently induced. miR-34a-5p mimic, oe-HDAC1, or ER-α activator Ferutinin was introduced in BMSCs. Alkaline phosphatase activity and calcification were detected. Expressions of miR-34a-5p, HDAC1, ER-α, and osteogenic markers were determined via RT-qPCR and Western blot. The binding relationship between miR-34a-5p and HDAC1 was verified by a dual-luciferase assay. Mice at the age of 6 months and 18 months were assigned to the young group and age group for in vivo experiments, and aged mice were treated with agomiR miR-34a-5p. Expressions of serum miR-34a-5p, HDAC1, ER-α, and bone metabolism markers in mice were determined. RESULTS: Osteogenic medium-induced BMSCs manifested increased expressions of miR-34a-5p and ER-α and decreased HDAC1 expression. miR-34a-5p overexpression promoted osteogenic differentiation of BMSCs. miR-34a-5p targeted HDAC1. HDAC1 overexpression partially counteracted the promotional action of miR-34a-5p overexpression on osteogenic differentiation of BMSCs. miR-34a-5p overexpression activated ER-α. ER-α activator Ferutinin partially nullified the regulatory function of miR-34a-5p/HDAC1 on osteogenic differentiation of BMSCs. In vivo experiments showed that miR-34a-5p overexpression enhanced the potential of bone metabolism in aged mice. CONCLUSION: miR-34a-5p overexpression promoted osteogenic differentiation of BMSCs and enhanced bone metabolism by promoting ER-α activation via targeting HDAC1.

Circular RNA hsa_circ_0005239 contributes to hepatocellular carcinoma cell migration, invasion, and angiogenesis by targeting the miR-34a-5p/PD-L1 axis.

Circular RNAs (circRNAs) may be involved in tumorigenesis. Recently, the role of circRNAs in hepatocellular carcinoma (HCC) has drawn wide attention. Herein, we aimed to explore the regulation and function of hsa_circ_0005239 in the malignant biological behavior and angiogenesis of HCC, as well as the link between hsa_circ_0005239 and programmed cell death ligand 1 (PD-L1) in HCC. Quantitative real-time polymerase chain reaction (qRT-PCR) assays revealed that hsa_circ_0005239 was upregulated in HCC tumor samples and cell lines. Furthermore, a series of in vitro and in vivo assays explored the effects of hsa_circ_0005239 on biological processes involved in the development of HCC. Knockdown of hsa_circ_0005239 significantly inhibited cell migration, cell invasion, and angiogenesis in HCC, while overexpression showed the opposite effect. In the in vivo assays, hsa_circ_0005239 downregulation suppressed the growth of xenograft tumors in nude mice, which supported that hsa_circ_0005239 is a tumor promoter in HCC. Mechanistically, hsa_circ_0005239 binds to miR-34a-5p and functions as a competing endogenous RNA to modulate the expression of PD-L1. Further experiments revealed that the hsa_circ_0005239/PD-L1 axis regulates the malignant phenotypes of HCC cells through the phosphoinositide-3 kinase/protein kinase B (PI3K/Akt) signaling pathway. These results revealed the role of hsa_circ_0005239 and the hsa_circ_0005239/miR-34a-5p/PD-L1 axis in HCC, providing a potential diagnostic biomarker and therapeutic target for HCC.

Engineering HEK293T cell line by lentivirus to produce miR34a-loaded exosomes.

BACKGROUND: RNA (ribonucleic acid) antisense is developing as a possible treatment option. As an RNA, miR-34a is involved in P53 function and cancer cell apoptosis. Although the therapeutic applications of miRNAs have several limitations, such as structural instability and susceptibility to nucleases. To resolve these issues, this study aims to apply exosomes as a delivery vehicle for miR-34a. AIMS: This study aims to create a cell factory to generate miR34a-enriched exosomes. The produced nanoparticles act as a delivery system and improve the structural stability of miR34a. METHODS: First exosome specific sequences were inserted into miR34a. The resulting miR34a oligonucleotide was transduced HEK293T cells genome with a lentiviral system. In the structure of miR34a oligonucleotide, six nucleotides were substituted to increase its packaging rate into exosomes. To maintain the secondary structure, stability, and expression of the miRNA gene, changes to the miR34a oligonucleotide were made using PCR (polymerase chain reaction) Extension. The forward-34a (5-TGGGGAGAGGCAGGACAGG-3) and Reverse-34a primers (5-TCCGAAGTCCTGGCGTCTCC-3) were used for amplification of the miR34a gene from DNA. RESULTS: The results confirmed that the changes in miR34a oligonucleotide do not affect its secondary structure. The energy level of the manipulated miR34a oligonucleotide was kept the same compared to the original one. Moreover, the loading of miR34a to the exosomes was increased. CONCLUSION: Our findings revealed that normal HEK293T did not express miR34a. However, lentiviral transduced miR34a oligonucleotide induced the loading of miR34a into the exosome. Moreover, replacing six nucleic acids in the 3' end of miR34a increased the loading of miR34a to exosome.

p53 downregulates PD-L1 expression via miR-34a to inhibit the growth of triple-negative breast cancer cells: a potential clinical immunotherapeutic target.

BACKGROUND: Compared with other breast cancer subtypes, triple-negative breast cancer (TNBC) has poorer responses to therapy and lower overall survival rates. The use of an inhibitor of immune checkpoint programmed cell death ligand 1 (PD-L1) is a promising treatment strategy and is approved for malignant tumors, especially for TNBC. p53 regulates various biological processes, but the association between p53 and immune evasion remains unknown. miR-34a is a known tumor suppressor and p53-regulated miRNA that is downregulated in several cancers; however, it has not been reported in TNBC. Herein, we aimed to explore the regulatory signaling axis among p53, miR-34a and PD-L1 in TNBC cells in vivo and in tissue and to improve our understanding of immunotherapy for TNBC. METHODS AND RESULTS: p53-EGFP, p53-siRNA and miR-34a mimics were transfected into TNBC cell lines, and the interaction between miR-34a and PD-L1 was analyzed via dual-luciferase reporter assays. We found that p53 could inhibit the expression of PD-L1 via miR-34a and that miR-34a could inhibit both cell activity and migration and promoted apoptosis and cytotoxicity in TNBC. Furthermore, miR-34a agomir was injected into MDA-MB-231 tumors of nude mice. The results showed that miR-34a could inhibit tumor growth and downregulate the expression of PD-L1 in vivo. A total of 133 TNBC tissue samples were analyzed by immunochemistry; the proportion of positive expression of PD-L1 was 57.14% (76/133), and the proportion of samples with negative expression of PD-L1 was 42.86% (57/133). CONCLUSION: Our research may provide a novel potential target for TNBC.