Strategies to antagonize miRNA functions in vitro and in vivo

Unveiling novel anti-viral mechanisms of ε-poly-l-lysine on tobacco mosaic virus-infected Nicotiana tabacum through microRNA and transcriptome sequencing

MicroRNAs (miRNAs) play important roles in plant defense against various pathogens. ε-poly-l-lysine (ε-PL), a natural anti-microbial peptide produced by microorganisms, effectively suppresses tobacco mosaic virus (TMV) infection. To investigate the anti-viral mechanism of ε-PL, the expression profiles of miRNAs in TMV-infected Nicotiana tabacum after ε-PL treatment were analyzed. The results showed that the expression levels of 328 miRNAs were significantly altered by ε-PL. Degradome sequencing was used to identify their target genes. Integrative analysis of miRNAs target genes and gene-enriched GO/KEGG pathways indicated that ε-PL regulates the expression of miRNAs involved in critical pathways of plant hormone signal transduction, host defense response, and plant pathogen interaction. Subsequently, virus induced gene silencing combined with the short tandem targets mimic technology was used to analyze the function of these miRNAs and their target genes. The results indicated that silencing miR319 and miR164 reduced TMV accumulation in N. benthamiana, indicating the essential roles of these miRNAs and their target genes during ε-PL-mediated anti-viral responses. Collectively, this study reveals that microbial source metabolites can inhibit plant viruses by regulating crucial host miRNAs and further elucidate anti-viral mechanisms of ε-PL.

The role of microRNAs in diseases and related signaling pathways

MicroRNAs (miRNAs) are epigenetic regulators of the gene expression and act through posttranslational modification. They bind to 3'-UTR of target mRNAs to inhibit translation or increase the degradation mRNA in many tissues. Any alteration in the level of miRNA expression in many human diseases indicates their involvement in the pathogenesis of many diseases. On the other hand, the regulation of the signaling pathways is necessary for the maintenance of natural and physiological characteristics of any cell. It is worth mentioning that dysfunction of the signaling pathways manifests itself as a disorder or disease. The significant evidence report that miRNAs regulate the several signaling pathways in many diseases. Base on previous studies, miRNAs can be used for therapeutic or diagnostic purposes. According to the important role of miRNAs on the cell signaling pathways, this article reviews miRNAs involvement in incidence of diseases by changing signaling pathways.

Multipotent miRNA Sponge-Loaded Magnetic Nanodroplets with Ultrasound/Magnet-Assisted Delivery for Hepatocellular Carcinoma Therapy

Gene therapy is likely to be the most promising way to tackle cancer, while defects in molecular strategies and delivery systems have led to an impasse in clinical application. Here, it is found that onco-miRNAs of the miR-515 and -449 families were upregulated in hepatocellular carcinoma (HCC), and the sponge targeting miR-515 family had a significant probability to suppress cancer cell proliferation. Then, we constructed non-toxic sponge-loaded magnetic nanodroplets containing 20% C6F14 (SLMNDs-20%) that are incorporated with fluorinated superparamagnetic iron oxide nanoparticles enhancing external magnetism-assisted targeting and enabling a direct visualization of SLMNDs-20% distribution in vivo via magnetic resonance imaging monitoring. SLMNDs-20% could be vaporized by programmable focused ultrasound (FUS) activation, achieving ∼45% in vitro sponge delivery efficiency and significantly enhancing in vivo sponge delivery without a clear apoptosis. Moreover, the sponge-1-carrying SLMNDs-20% could effectively suppress proliferation of xenograft HCC after FUS exposure because sponge-1-suppressing onco-miR-515 enhanced the expression of anti-oncogenes (P21, CD22, TIMP1, NFKB, and E-cadherin) in cancer cells. The current results indicated that ultrasonic cavitation-inducing sonoporation enhanced the intracellular delivery of sponge-1 using SLMNDs-20% after magnetic-assisted accumulation, which was a therapeutic approach to inhibit HCC progression.

Dysregulation of serum miR-1204 and its potential as a biomarker for the diagnosis and prognosis of breast cancer

OBJECTIVE A previous study has reported that miR-1204 exerted oncogenic effects in breast cancer (BC). The purpose of our paper was to evaluate the expressions of tissue and serum miR-1204 in patients with BC and further investigate its biomarker potential. METHODS The expressions of tissue and serum miR-1204 were investigated by qRT-PCR in 144 BC patients and 38 healthy controls. Chi-square tests were conducted to examine the associations between miR-1204 expressions and clinicopathological factors. Then, the associations of miR-1204s level with the survival of BC patients were determined by performing the Kaplan-Meier and multivariate analysis. The receiver operating characteristics (ROC) and area under the OC curve (AUC) were obtained to validate the diagnostic values of miR-1204. RESULTS We found that the expressions of miR-1204 were increased in both tissue and serum samples from BC patients. Multivariate assays identified tissue and serum miR-1204 overexpression as an independent poor prognostic factor. In addition, ROC curve assays indicated that tissue and serum miR-1204 are potential diagnostic markers of BC. CONCLUSIONS Detection of tissue and serum miR-1204 levels could have clinical potential as a novel prognostic/diagnostic biomarker for BC patients.

Downregulation of miRNA‑328 promotes the angiogenesis of HUVECs by regulating the PIM1 and AKT/mTOR signaling pathway under high glucose and low serum condition

Vascular complications are the primary reason for disability and mortality associated with diabetes mellitus (DM), and numerous microRNAs (miRNAs/miRs) are involved in the process, such as miR‑122, miR‑24 and miR‑423. It has been reported that miR‑328 regulates DM and cardiovascular disease; however, the role and mechanism of action underlying miR‑328 in HUVECs is not completely understood. The present study aimed to investigate the role and mechanism of action underlying the effects of miR‑328 on the functions of HUVECs. To simulate hyperglycemia combined with ischemia‑induced tissue starvation, HUVECs were cultured in endothelial cell medium with 25 mmol/l D‑glucose and 2% FBS for 24 h [high glucose (HG) + 2% FBS group]. HUVEC miR‑328 expression levels were detected by reverse transcription‑quantitative PCR. Cell migration, cytotoxicity and tube‑like structure formation were analyzed using wound healing, Cell Counting Kit‑8 and tube formation assays, respectively. Following transfection with miR‑328 inhibitor, miR‑328 expression was downregulated in HUVECs. Protein expression levels were determined by western blotting. Compared with the control group, the migration and tube‑like structure formation of HUVECs were decreased, and cell cytotoxicity was increased in the HG + 2% FBS group. The protein expression levels of vascular endothelial growth factor were also decreased, and the expression levels of miRNA‑328 in the HG + 2% FBS group were increased compared with the control group. However, miRNA‑328 downregulation reversed the aforementioned effects. Further experiments indicated that the AKT signaling pathway was inhibited in the HG + 2% FBS group; however, miR‑328 downregulation activated the AKT/mTOR signaling pathway, which was blocked by the AKT signaling pathway inhibitor, perifosine. Gene prediction and western blotting demonstrated that miR‑328 displayed a regulatory role via Pim‑1 proto‑oncogene, serine/threonine kinase (PIM1). In conclusion, miR‑328 expression was upregulated and angiogenesis was inhibited when HUVECs were subjected to high glucose and low serum conditions. miR‑328 downregulation enhanced angiogenesis by increasing PIM1 expression and activating the AKT/mTOR signaling pathway in HUVECs under high glucose and low serum conditions.

MiR-210-3p inhibits osteogenic differentiation and promotes adipogenic differentiation correlated with Wnt signaling in ERα-deficient rBMSCs

MicroRNAs (miRNAs) regulate activities in living organisms through various signaling pathways and play important roles in the development and progression of osteoporosis. The balance between osteogenic and adipogenic differentiation of rBMSCs is closely related to the occurrence of osteoporosis. ERα regulates bone metabolism in various tissues. However, the correlation among ERα, miRNAs, and the differentiation of rBMSCs is still unclear. In this study, we used lentivirus transfection into rBMSCs to construct an ERα-deficient model, analyzed the differences in expressed miRNAs between control and ERα-deficient rBMSCs. The results revealed that the expression of 25 miRNAs were upregulated, 164 miRNAs were downregulated, and some of the regulated miRNAs such as miR-210-3p and miR-214-3p were related to osteogenic or adipogenic differentiation, as well as to particular signaling pathways. Next, we overexpressed miR-210-3p to evaluate its effects on the osteogenic and adipogenic differentiation of rBMSCs, and identified the relationship among miR-210-3p, Wnt signaling pathway, and the differentiation of rBMSCs. The results indicated that ERα-deficient inhibited osteogenic differentiation, promoted adipogenic differentiation, and regulated the expression of some miRNAs. Meanwhile, overexpression of miR-210-3p promoted osteogenic differentiation and inhibited adipogenic differentiation of rBMSCs, processes likely to be related to the Wnt signaling pathway. In conclusion, we identified a group of upregulated and downregulated miRNAs in ERα-deficient rBMSCs that might play a vital role in regulating osteogenic or adipogenic differentiation. One of these, miR-210-3p, inhibited osteogenic differentiation and promoted adipogenic differentiation correlated with the Wnt signaling pathway in ERα-deficient rBMSCs, providing new insight into the regulation of bone metabolism.

miRNAs and their roles in KSHV pathogenesis

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman Disease (MCD). Recent mechanistic advances have discerned the importance of microRNAs in the virus-host relationship. KSHV has two modes of replication: lytic and latent phase. KSHV entry into permissive cells, establishment of infection, and maintenance of latency are contingent upon successful modulation of the host miRNA transcriptome. Apart from host cell miRNAs, KSHV also encodes viral miRNAs. Among various cellular and molecular targets, miRNAs are appearing to be key players in regulating viral pathogenesis. Therefore, the use of miRNAs as novel therapeutics has gained considerable attention as of late. This innovative approach relies on either mimicking miRNA species by identical oligonucleotides, or selective silencing of miRNA with specific oligonucleotide inhibitors. Here, we provide an overview of KSHV pathogenesis at the molecular level with special emphasis on the various roles miRNAs play during virus infection.

The potential roles of circRNAs in osteoarthritis: a coming journey to find a treasure

Osteoarthritis (OA), a common joint disease in elderly, causes serious social and economic burdens worldwide. Previous studies indicated that some differentially expressed circular RNAs (circRNAs) participated in the initiation and progression of OA. These findings suggested that circRNAs may act as promising diagnostic biomarkers and therapeutic targets for OA. In this review, we summarize the biogenesis and biological functions of circRNAs and explore the underlying roles of circRNAs in OA, which may enlighten further studies and contribute to the early diagnosis and intervention of OA.

Effects of human cyclooxygenase-2 gene silencing on synovial cells of rheumatoid arthritis mediated by lentivirus

The aim of the study is to screen the effective shRNA sequence which can silence the human COX-2 expression level in synovial cells of rheumatoid arthritis (RA) patient transfected by the lentivirus. Four pairs of hCOX-2 shRNA were designed and inserted into lentivirus to form pGPHI/GFP/Neo-shRNA vector. The reconstructed virus was transfected into synovial cells derived from RA patients, and then the expression level of hCOX-2 mRNA and the protein of the inflammatory factors including prostaglandin E2 (PGE2), vascular endothelial growth factor (VEGF), interleukin-1β (IL-1β) and tumour necrosis factor alpha (TNF-α) in the supernatants were examined with real-time PCR and ELISA, respectively. There was no obvious negative influence on cell growth and morphology after hCOX-2 shRNA gene transfection mediated by lentivirus. The hCOX-2 mRNA expression level, as well as the concentration of PGE2, VEGF, IL-1β and TNF-α, decreased significantly (p < .05). RNAi mediated by lentivirus can significantly inhibit hCOX-2 mRNA expression level in synovial cells of RA patients, so as to reduce the expression of inflammatory cytokines.

Bone protection by inhibition of microRNA-182

Targeting microRNAs recently shows significant therapeutic promise; however, such progress is underdeveloped in treatment of skeletal diseases with osteolysis, such as osteoporosis and rheumatoid arthritis (RA). Here, we identified miR-182 as a key osteoclastogenic regulator in bone homeostasis and diseases. Myeloid-specific deletion of miR-182 protects mice against excessive osteoclastogenesis and bone resorption in disease models of ovariectomy-induced osteoporosis and inflammatory arthritis. Pharmacological treatment of these diseases with miR-182 inhibitors completely suppresses pathologic bone erosion. Mechanistically, we identify protein kinase double-stranded RNA-dependent (PKR) as a new and essential miR-182 target that is a novel inhibitor of osteoclastogenesis via regulation of the endogenous interferon (IFN)-β-mediated autocrine feedback loop. The expression levels of miR-182, PKR, and IFN-β are altered in RA and are significantly correlated with the osteoclastogenic capacity of RA monocytes. Our findings reveal a previously unrecognized regulatory network mediated by miR-182-PKR-IFN-β axis in osteoclastogenesis, and highlight the therapeutic implications of miR-182 inhibition in osteoprotection.

Osteoclasts mediate bone disruption in a number of degenerative bone diseases. Here, the authors show that miR-182 regulates osteoclastogenesis via PKR and IFN-beta signaling, is correlated with rheumatoid arthritis, and that its ablation or inhibition is protective against bone erosion in mouse models of osteoporosis or inflammatory arthritis.

Assessing the Off-Target Effects of miRNA Inhibitors on Innate Immune Toll-Like Receptors

MicroRNAs (miRNAs) are involved in most cellular processes and are deregulated in several diseases. Antisense miRNA oligonucleotides (AMOs) therefore present novel therapeutic opportunities. Currently, in vivo delivery of AMOs often relies on high doses of nucleic acids, with nonspecific uptake by most tissues. Critically, AMOs accumulate in phagocytic cells where they can interfere with immune functions, such as the activation of Toll-Like Receptors (TLRs). In this chapter, we describe a method to assess the possible off-target effects of AMOs on TLR7, 8, and 9 sensing.

MicroRNAs and cancer: Key paradigms in molecular therapy

MicroRNAs (miRNAs) are a type of small non-coding RNA molecule that performs an important role in post-transcriptional gene regulation. Since miRNAs were first identified in 1993, a number of studies have demonstrated that they act as tumor suppressors or oncogenes in human cancer, including colorectal, lung, brain, breast and liver cancer, and leukemia. Large high-throughput studies have previously revealed that miRNA profiling is critical for the diagnosis and prognosis of patients with cancer, while certain miRNAs possess the potential to be used as diagnostic and prognostic biomarkers or therapeutic targets in cancer. The present study reviews the studies and examines the roles of miRNAs in cancer diagnosis, prognosis and treatment, and discusses the potential therapeutic modality of exploiting miRNAs.