Subcellular fate and off-target effects of siRNA, shRNA, and miRNA. Pharm Res. 2011;28:2996-3015. [PMID: 22033880 DOI: 10.1007/s11095-011-0608-1]

MicroRNA dysregulation in glutamate and dopamine pathways of schizophrenia: From molecular pathways to diagnostic and therapeutic approaches

Schizophrenia is a complex psychiatric disorder, and genetic and environmental factors have been implicated in its development. Dysregulated glutamatergic and dopaminergic transmission pathways are involved in schizophrenia development. Besides genetic mutations, epigenetic dysregulation has a considerable role in dysregulating molecular pathways involved in schizophrenia. MicroRNAs (miRNAs) are small, non-coding RNAs that target specific mRNAs and inhibit their translation into proteins. As epigenetic factors, miRNAs regulate many genes involved in glutamate and dopamine signaling pathways; thereby, their dysregulation can contribute to the development of schizophrenia. Secretion of specific miRNAs from damaged cells into body fluids can make them one of the ideal non-invasive biomarkers in the early diagnosis of schizophrenia. Also, understanding the molecular mechanisms of miRNAs in schizophrenia pathogenesis can pave the way for developing novel treatments for patients with schizophrenia. In this study, we reviewed the glutamatergic and dopaminergic pathophysiology and highlighted the role of miRNA dysregulation in schizophrenia development. Besides, we shed light on the significance of circulating miRNAs for schizophrenia diagnosis and the recent findings on the miRNA-based treatment for schizophrenia.

Radiation-sensitive circRNA hsa_circ_0096498 inhibits radiation-induced liver fibrosis by suppressing EIF4A3 nuclear translocation to decrease CDC42 expression in hepatic stellate cells

BACKGROUND

Radiation-induced liver fibrosis (RILF) is a common manifestation of radiation-induced liver injury (RILI) and is caused primarily by activated hepatic stellate cells (HSCs). Circular RNAs (circRNAs) play critical roles in various diseases, but little is known about the function and mechanism of circRNAs in RILF.

METHODS

RNA pull-down and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to screen binding proteins of hsa_circ_0096498 (circ96498). RNA-binding protein immunoprecipitation, RNA pull-down and nuclear and cytoplasmic protein extraction were conducted to confirm the interaction between circ96498 and eukaryotic initiation factor 4A3 (EIF4A3). RNA sequencing was performed to screen target genes regulated by EIF4A3. HSCs with altered circ96498 and cell division cycle 42 (CDC42) expression were used to assess irradiated HSC activation. Circ96498 inhibition and CDC42 blockade were evaluated in RILF mouse models.

RESULTS

In this study, we identified a radiation-sensitive circ96498, which was highly expressed in the irradiated HSCs of paracancerous tissues from RILI patients. Circ96498 inhibited the proliferation but promoted the apoptosis of irradiated HSCs, suppressed the secretion of proinflammatory cytokines IL-1β, IL-6 and TNF-α, and decreased the expression of profibrotic markers (α-SMA and collagen 1) in irradiated HSCs. Mechanistically, irradiation induced the transport of EIF4A3 into the nucleus, and nuclear EIF4A3 increased the stability of CDC42 mRNA and increased CDC42 expression, thereby promoting HSC activation through the NF-κB and JNK/Smad2 pathways. However, the binding of circ96498 to EIF4A3 impeded the translocation of EIF4A3 into the nucleus, resulting in the inhibition of CDC42 expression and subsequent HSC activation. Furthermore, circ96498 knockdown promoted the development of the early and late stages of RILF in a mouse model, which was mitigated by CDC42 blockade.

CONCLUSIONS

Collectively, our findings elucidate the involvement of the circ96498/EIF4A3/CDC42 axis in inhibiting irradiated HSC activation, which offers a novel approach for RILF prevention and treatment.

Intracellular delivery of antiviral shRNA using penetratin-based complexes effectively inhibits respiratory syncytial virus replication and host cell apoptosis

BACKGROUND

Cell-penetrating peptides (CPPs) are effective for delivering therapeutic molecules with minimal toxicity. This study focuses on the use of penetratin, a well-characterized CPP, to deliver a DNA vector encoding short hairpin RNA (shRNA) targeting the respiratory syncytial virus (RSV) F gene into infected cells. RSV is known to cause severe lower respiratory infections in infants and poses significant risks to immunocompromised individuals and the elderly. We evaluated the antiviral efficacy of the penetratin-shRNA complex by comparing its ability to inhibit RSV replication and induce apoptosis with ribavirin treatment.

METHODS

Penetratin-shRNA complexes were prepared at different ratios and analyzed using gel retardation assays, dynamic light scattering, and zeta potential measurements. The complexes were tested in HEp-2 and A549 cells for transfection efficiency, cytotoxicity, viral load, and apoptosis using plaque assays, real-time reverse transcription-polymerase chain reaction (RT-PCR), DNA fragmentation, propidium iodide staining, and caspase 3/7 activation assays.

RESULTS

The gel shift assay determined that a 20:1 CPP-to-shRNA ratio was optimal for effective complexation, resulting in particles with a size of 164 nm and a zeta potential of 8.7 mV. Transfection efficiency in HEp-2 cells was highest at this ratio, reaching up to 93%. The penetratin-shRNA complex effectively silenced the RSV F gene, reduced viral titers, and decreased DNA fragmentation and apoptosis in infected cells.

CONCLUSION

Penetratin effectively delivers shRNA targeting the RSV F gene, significantly reducing viral load and preventing apoptosis without toxicity. This approach surpasses Lipofectamine and shows potential for future therapeutic interventions, especially when combined with ribavirin, against RSV infection.

Advancements and challenges in mRNA and ribonucleoprotein-based therapies: From delivery systems to clinical applications

The use of mRNA and ribonucleoproteins (RNPs) as therapeutic agents is a promising strategy for treating diseases such as cancer and infectious diseases. This review provides recent advancements and challenges in mRNA- and RNP-based therapies, focusing on delivery systems such as lipid nanoparticles (LNPs), which ensure efficient delivery to target cells. Strategies such as microfluidic devices are employed to prepare LNPs loaded with mRNA and RNPs, demonstrating effective genome editing and protein expression in vitro and in vivo. These applications extend to cancer treatment and infectious disease management, with promising results in genome editing for cancer therapy using LNPs encapsulating Cas9 mRNA and single-guide RNA. In addition, tissue-specific targeting strategies offer potential for improved therapeutic outcomes and reduced off-target effects. Despite progress, challenges such as optimizing delivery efficiency and targeting remain. Future research should enhance delivery efficiency, explore tissue-specific targeting, investigate combination therapies, and advance clinical translation. In conclusion, mRNA- and RNP-based therapies offer a promising avenue for treating various diseases and have the potential to revolutionize medicine, providing new hope for patients worldwide.

The multifaceted roles of circular RNAs in cancer hallmarks: From mechanisms to clinical implications

Circular RNAs (circRNAs) represent a distinct class of covalently closed RNA species lacking conventional 5' to 3' polarity. Derived predominantly from pre-mRNA transcripts of protein-coding genes, circRNAs arise through back-splicing events of exon-exon or exon-intron junctions. They exhibit tissue- and cell-specific expression patterns and play crucial roles in regulating fundamental cellular processes such as cell cycle dynamics, proliferation, apoptosis, and differentiation. CircRNAs modulate gene expression through a plethora of mechanisms at epigenetic, transcriptional, and post-transcriptional levels, and some can even undergo translation into functional proteins. Recently, aberrant expression of circRNAs has emerged as a significant molecular aberration within the intricate regulatory networks governing hallmarks of cancer. The tumor-specific expression patterns and remarkable stability of circRNAs have profound implications for cancer diagnosis, prognosis, and therapy. This review comprehensively explores the multifaceted roles of circRNAs across cancer hallmarks in various tumor types, underscoring their growing significance in cancer diagnosis and therapeutic interventions. It also details strategies for leveraging circRNA-based therapies and discusses the challenges in using circRNAs for cancer management, emphasizing the need for further research to overcome these obstacles.

CircPRRC2C Promotes the Oncogenic Phenotypes of Laryngeal Squamous Cell Carcinoma Cells via MiR-136-5p/HOXD11 Axis

The involvement of circular RNAs (circRNAs) in laryngeal squamous cell carcinoma (LSCC) carcinogenesis has gradually been proposed. Herein, we aimed to explore the function and mechanism of circPRRC2C in LSCC. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used for detecting the content of genes and proteins. In vitro experiments were conducted using 5-ethynyl-2'-deoxyuridine, colony formation, flow cytometry, and transwell assays. The binding between miR-136-5p and circPRRC2C or Homeobox D11 (HOXD11) was confirmed by using the dual-luciferase reporter assay. The murine xenograft model was established for in vivo analysis. The commercial kit was used for exosome separation. CircPRRC2C is a stable circRNA, and was highly expressed in LSCC tissues and cell lines. Functionally, circPRRC2C deficiency impaired LSCC cell proliferation, migration and invasion but induced cell apoptosis in vitro and impeded tumor growth in vivo, however, circPRRC2C overexpression showed the exact opposite effects. Mechanistically, circPRRC2C directly targeted miR-136-5p, which showed inhibitory effects on the growth and mobility of LSCC cells. Meanwhile, miR-136-5p directly targeted HOXD11, and circPRRC2C/miR-136-5p/HOXD11 formed a feedback loop in LSCC cells. Further rescue assays exhibited that circPRRC2C exerted its effects by miR-136-5p/HOXD11 axis. In addition, circPRRC2C was stably packaged into exosomes and showed potential diagnostic value for LSCC. CircPRRC2C acted as an oncogene to promote LSCC cell oncogenic phenotypes via miR-136-5p/HOXD11 axis, besides, circPRRC2C was stably packaged into exosomes, indicating the potential application of circPRRC2C-targeting agents in the treatment in LSCC.

CircZFR promotes colorectal cancer progression via stabilizing BCLAF1 and regulating the miR-3127-5p/RTKN2 axis

Aberrant expression of circular RNAs (circRNAs) is frequently linked to colorectal cancer (CRC). Here, we identified circZFR as a promising biomarker for CRC diagnosis and prognosis. CircZFR was upregulated in CRC tissues and serum exosomes and its level was linked to cancer incidence, advanced-stages, and metastasis. In both in vitro and in vivo settings, circZFR promoted the growth and spread while suppressing apoptosis of CRC. Exosomes with circZFR overexpression promoted the proliferation and migration of cocultured CRC cells. Mechanistically, epithelial splicing regulatory protein 1 (ESRP1) in CRC cells may enhance the production of circZFR. BCL2-associated transcription factor 1 (BCLAF1) bound to circZFR, which prevented its ubiquitinated degradation. Additionally, circZFR sponged miR-3127-5p to boost rhotekin 2 (RTKN2) expression. Our TCP1-CD-QDs nanocarrier was able to carry and deliver circZFR siRNA (si-circZFR) to the vasculature of CRC tissues and cells, which inhibited the growth of tumors in patient-derived xenograft (PDX) models. Taken together, our results show that circZFR is an oncogenic circRNA, which promotes the development and spread of CRC in a BCLAF1 and miR-3127-5p-dependent manner. CircZFR is a possible serum biopsy marker for the diagnosis and a desirable target for further treatment of CRC.

CircRNA as an Achilles heel of cancer: characterization, biomarker and therapeutic modalities

Circular RNAs (circRNAs) are a class of endogenous noncoding RNAs characterized by their lack of 5' caps and 3' poly(A) tails. These molecules have garnered substantial attention from the scientific community. A wide range of circRNA types has been found to be expressed in various tissues of the human body, exhibiting unique characteristics such as high abundance, remarkable stability, and tissue-specific expression patterns. These attributes, along with their detectability in liquid biopsy samples such as plasma, position circRNAs an ideal choice as cancer diagnostic and prognostic biomarkers. Additionally, several studies have reported that the functions of circRNAs are associated with tumor proliferation, metastasis, and drug resistance. They achieve this through various mechanisms, including modulation of parental gene expression, regulation of gene transcription, acting as microRNA (miRNA) sponges, and encoding functional proteins. In recent years, a large number of studies have focused on synthesizing circRNAs in vitro and delivering them to tumor tissue to exert its effects in inhibit tumor progression. Herein, we briefly discuss the biogenesis, characteristics, functions, and detection of circRNAs, emphasizing their clinical potential as biomarkers for cancer diagnosis and prognosis. We also provide an overview the recent techniques for synthesizing circRNAs and delivery strategies, and outline the application of engineered circRNAs in clinical cancer therapy.

Unlocking biological mechanisms with integrative functional genomics approaches

Reverse genetics offers precise functional insights into genes through the targeted manipulation of gene expression followed by phenotypic assessment. While these approaches have proven effective in model organisms such as Saccharomyces cerevisiae, large-scale genetic manipulations in human cells were historically unfeasible due to methodological limitations. However, recent advancements in functional genomics, particularly clustered regularly interspaced short palindromic repeats (CRISPR)-based screening technologies and next-generation sequencing platforms, have enabled pooled screening technologies that allow massively parallel, unbiased assessments of biological phenomena in human cells. This review provides a comprehensive overview of cutting-edge functional genomic screening technologies applicable to human cells, ranging from short hairpin RNA screens to modern CRISPR screens. Additionally, we explore the integration of CRISPR platforms with single-cell approaches to monitor gene expression, chromatin accessibility, epigenetic regulation, and chromatin architecture following genetic perturbations at the omics level. By offering an in-depth understanding of these genomic screening methods, this review aims to provide insights into more targeted and effective strategies for genomic research and personalized medicine.

Advanced strategies of targeting circular RNAs as therapeutic approaches in colorectal cancer drug resistance

Colorectal cancer (CRC) stands second in terms of mortality and third among the highest prevalent kinds of cancer globally. CRC prevalence is rising in moderately and poorly developed regions and is greater in economically advanced regions. Despite breakthroughs in targeted therapy, resistance to chemotherapeutics remains a significant challenge in the long-term management of CRC. Circular RNAs (circRNAs) have been involved in growing cancer therapy resistance, particularly in CRC, according to an increasing number of studies in recent years. CircRNAs are one of the novel subclasses of non-coding RNAs, previously thought of as viroid. According to studies, circRNAs have been recommended as biological markers for therapeutic targets and diagnostic and prognostic purposes. That is particularly notable given that the expression of circRNAs has been linked to the hallmarks of CRC since they are responsible for drug resistance in CRC patients; thereby, circRNAs are significant for chemotherapy failure. Moreover, knowledge concerning circRNAs remains relatively unclear despite using all these advanced techniques. Here, in this study, we will go over the most recent published work to highlight the critical roles of circRNAs in CRC development and drug resistance and highlight the main strategies to overcome drug resistance to improve clinical outcomes.

Engineering circular RNA for molecular and metabolic reprogramming

The role of messenger RNA (mRNA) in biological systems is extremely versatile. However, it's extremely short half-life poses a fundamental restriction on its application. Moreover, the translation efficiency of mRNA is also limited. On the contrary, circular RNAs, also known as circRNAs, are a common and stable form of RNA found in eukaryotic cells. These molecules are synthesized via back-splicing. Both synthetic circRNAs and certain endogenous circRNAs have the potential to encode proteins, hence suggesting the potential of circRNA as a gene expression machinery. Herein, we aim to summarize all engineering aspects that allow exogenous circular RNA (circRNA) to prolong the time that proteins are expressed from full-length RNA signals. This review presents a systematic engineering approach that have been devised to efficiently assemble circRNAs and evaluate several aspects that have an impact on protein production derived from. We have also reviewed how optimization of the key components of circRNAs, including the topology of vector, 5' and 3' untranslated sections, entrance site of the internal ribosome, and engineered aptamers could be efficiently impacting the translation machinery for molecular and metabolic reprogramming. Collectively, molecular and metabolic reprogramming present a novel way of regulating distinctive cellular features, for instance growth traits to neoplastic cells, and offer new possibilities for therapeutic inventions.

IDH1 mutation produces R-2-hydroxyglutarate (R-2HG) and induces mir-182-5p expression to regulate cell cycle and tumor formation in glioma

BACKGROUND

Mutations in isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2), are present in most gliomas. IDH1 mutation is an important prognostic marker in glioma. However, its regulatory mechanism in glioma remains incompletely understood.

RESULTS

miR-182-5p expression was increased within IDH1-mutant glioma specimens according to TCGA, CGGA, and online dataset GSE119740, as well as collected clinical samples. (R)-2-hydroxyglutarate ((R)-2HG) treatment up-regulated the expression of miR-182-5p, enhanced glioma cell proliferation, and suppressed apoptosis; miR-182-5p inhibition partially eliminated the oncogenic effects of R-2HG upon glioma cells. By direct binding to Cyclin Dependent Kinase Inhibitor 2 C (CDKN2C) 3'UTR, miR-182-5p inhibited CDKN2C expression. Regarding cellular functions, CDKN2C knockdown promoted R-2HG-treated glioma cell viability, suppressed apoptosis, and relieved cell cycle arrest. Furthermore, CDKN2C knockdown partially attenuated the effects of miR-182-5p inhibition on cell phenotypes. Moreover, CDKN2C knockdown exerted opposite effects on cell cycle check point and apoptosis markers to those of miR-182-5p inhibition; also, CDKN2C knockdown partially attenuated the functions of miR-182-5p inhibition in cell cycle check point and apoptosis markers. The engineered CS-NPs (antagomir-182-5p) effectively encapsulated and delivered antagomir-182-5p, enhancing anti-tumor efficacy in vivo, indicating the therapeutic potential of CS-NPs(antagomir-182-5p) in targeting the miR-182-5p/CDKN2C axis against R-2HG-driven oncogenesis in mice models.

CONCLUSIONS

These insights highlight the potential of CS-NPs(antagomir-182-5p) to target the miR-182-5p/CDKN2C axis, offering a promising therapeutic avenue against R-2HG's oncogenic influence to glioma.

MicroRNA-26a in respiratory diseases: mechanisms and therapeutic potential

MicroRNAs (miRNAs) are short, non-coding single-stranded RNA molecules approximately 22 nucleotides in length, intricately involved in post-transcriptional gene expression regulation. Over recent years, researchers have focused keenly on miRNAs, delving into their mechanisms in various diseases such as cancers. Among these, miR-26a emerges as a pivotal player in respiratory ailments such as pneumonia, idiopathic pulmonary fibrosis, lung cancer, asthma, and chronic obstructive pulmonary disease. Studies have underscored the significance of miR-26a in the pathogenesis and progression of respiratory diseases, positioning it as a promising therapeutic target. Nevertheless, several challenges persist in devising medical strategies for clinical trials involving miR-26a. In this review, we summarize the regulatory role and significance of miR-26a in respiratory diseases, and we analyze and elucidate the challenges related to miR-26a druggability, encompassing issues such as the efficiency of miR-26a, delivery, RNA modification, off-target effects, and the envisioned therapeutic potential of miR-26a in clinical settings.

A biomimetic camouflaged metal organic framework for enhanced siRNA delivery in the tumor environment

Gene silencing through RNA interference (RNAi), particularly using small double-stranded RNA (siRNA), has been identified as a potent strategy for targeted cancer treatment. Yet, its application faces challenges such as nuclease degradation, inefficient cellular uptake, endosomal entrapment, off-target effects, and immune responses, which have hindered its effective delivery. In the past few years, these challenges have been addressed significantly by using camouflaged metal-organic framework (MOF) nanocarriers. These nanocarriers protect siRNA from degradation, enhance cellular uptake, and reduce unintended side effects by effectively targeting desired cells while evading immune detection. By combining the properties of biomimetic membranes and MOFs, these nanocarriers offer superior benefits such as extended circulation times, enhanced stability, and reduced immune responses. Moreover, through ligand-receptor interactions, biomimetic membrane-coated MOFs achieve homologous targeting, minimizing off-target adverse effects. The MOFs, acting as the core, efficiently encapsulate and protect siRNA molecules, while the biomimetic membrane-coated surface provides homologous targeting, further increasing the precision of siRNA delivery to cancer cells. In particular, the biomimetic membranes help to shield the MOFs from the immune system, avoiding unwanted immune responses and improving their biocompatibility. The combination of siRNA with innovative nanocarriers, such as camouflaged-MOFs, presents a significant advancement in cancer therapy. The ability to deliver siRNA with precision and effectiveness using these camouflaged nanocarriers holds great promise for achieving more personalized and efficient cancer treatments in the future. This review article discusses the significant progress made in the development of siRNA therapeutics for cancer, focusing on their effective delivery through novel nanocarriers, with a particular emphasis on the role of metal-organic frameworks (MOFs) as camouflaged nanocarriers.

Near-Infrared Induced miR-34a Delivery from Nanoparticles in Esophageal Cancer Treatment

Current nucleic acid delivery methods have not achieved efficient, non-toxic delivery of miRNAs with tumor-specific selectivity. In this study, a new delivery system based on light-inducible gold-silver-gold, core-shell-shell (CSS) nanoparticles is presented. This system delivers small nucleic acid therapeutics with precise spatiotemporal control, demonstrating the potential for achieving tumor-specific selectivity and efficient delivery of miRNA mimics. The light-inducible particles leverage the photothermal heating of metal nanoparticles due to the local surface plasmonic resonance for controlled chemical cleavage and release of the miRNA mimic payload. The CSS morphology and composition result in a plasmonic resonance within the near-infrared (NIR) region of the light spectrum. Through this method, exogenous miR-34a-5p mimics are effectively delivered to human squamous cell carcinoma TE10 cells, leading to apoptosis induction without adverse effects on untransformed keratinocytes in vitro. The CSS nanoparticle delivery system is tested in vivo in Foxn1nu athymic nude mice with bilateral human esophageal TE10 cancer cells xenografts. These experiments reveal that this CSS nanoparticle conjugates, when systemically administered, followed by 850 nm light emitting diode irradiation at the tumor site, 6 h post-injection, produce a significant and sustained reduction in tumor volume, exceeding 87% in less than 72 h.

Role of circular RNAs and gut microbiome in gastrointestinal cancers and therapeutic targets

Gastrointestinal cancers are a huge worldwide health concern, which includes a wide variety of digestive tract cancers. Circular RNAs (circRNAs), a kind of non-coding RNA (ncRNAs), are a family of single-stranded, covalently closed RNAs that have become recognized as crucial gene expression regulators, having an impact on several cellular functions in cancer biology. The gut microbiome, which consists of several different bacteria, actively contributes to the regulation of host immunity, inflammation, and metabolism. CircRNAs and the gut microbiome interact significantly to greatly affect the growth of GI cancer. Several studies focus on the complex functions of circRNAs and the gut microbiota in GI cancers, including esophageal cancer, colorectal cancer, gastric cancer, hepatocellular cancer, and pancreatic cancer. It also emphasizes how changed circRNA expression profiles and gut microbiota affect pathways connected to malignancy as well as how circRNAs affect hallmarks of gastrointestinal cancers. Furthermore, circRNAs and gut microbiota have been recommended as biological markers for therapeutic targets as well as diagnostic and prognostic purposes. Targeting circRNAs and the gut microbiota for the treatment of gastrointestinal cancers is also being continued to study. Despite significant initiatives, the connection between circRNAs and the gut microbiota and the emergence of gastrointestinal cancers remains poorly understood. In this study, we will go over the most recent studies to emphasize the key roles of circRNAs and gut microbiota in gastrointestinal cancer progression and therapeutic options. In order to create effective therapies and plan for the future gastrointestinal therapy, it is important to comprehend the functions and mechanisms of circRNAs and the gut microbiota.

Bioconjugation Techniques for Enhancing Stability and Targeting Efficiency of Protein and Peptide Therapeutics

Bioconjugation techniques have emerged as powerful tools for enhancing the stability and targeting efficiency of protein and peptide therapeutics. This review provides a comprehensive analysis of the various bioconjugation strategies employed in the field. The introduction highlights the significance of bioconjugation techniques in addressing stability and targeting challenges associated with protein and peptide-based drugs. Chemical and enzymatic bioconjugation methods are discussed, along with crosslinking strategies for covalent attachment and site-specific conjugation approaches. The role of bioconjugation in improving stability profiles is explored, showcasing case studies that demonstrate successful stability enhancement. Furthermore, bioconjugation techniques for ligand attachment and targeting are presented, accompanied by examples of targeted protein and peptide therapeutics. The review also covers bioconjugation approaches for prolonging circulation and controlled release, focusing on strategies to extend half-life, reduce clearance, and design-controlled release systems. Analytical characterization techniques for bioconjugates, including the evaluation of conjugation efficiency, stability, and assessment of biological activity and targeting efficiency, are thoroughly examined. In vivo considerations and clinical applications of bioconjugated protein and peptide therapeutics, including pharmacokinetic and pharmacodynamic considerations, as well as preclinical and clinical developments, are discussed. Finally, the review concludes with an overview of future perspectives, emphasizing the potential for novel conjugation methods and advanced targeting strategies to further enhance the stability and targeting efficiency of protein and peptide therapeutics.

miRNA contributes to neuropathic pains

Neuropathic pain (NP) is a kind of chronic pain caused by direct injury to the peripheral or central nervous system (CNS). microRNAs (miRNAs) are small noncoding RNAs that mostly interact with the 3 untranslated region of messenger RNAs (mRNAs) to regulate the expression of multiple genes. NP is characterized by changes in the expression of receptors and mediators, and there is evidence that miRNAs may contribute to some of these alterations. In this review, we aimed to fully comprehend the connection between NP and miRNA; and also, to establish a link between neurology, biology, and dentistry. Studies have shown that targeting miRNAs may be an effective therapeutic strategy for the treatment of chronic pain and potential target for the prevention of NP.

Therapeutic Effects of Mechanical Stress-Induced C2C12-Derived Exosomes on Glucocorticoid-Induced Osteoporosis Through miR-92a-3p/PTEN/AKT Signaling Pathway

Introduction

Osteoporosis is a common bone disease in which the bone loses density and strength and is prone to fracture. Bone marrow mesenchymal stem cells (BMSCs) are important in bone-related diseases. Exosomes, as mediators of cell communication, have potential in cell processes. Previous studies have focused on muscle factors' regulation of bone remodeling, but research on exosomes is lacking.

Methods

 In order to confirm the therapeutic effect of mechanically stimulated myocytes (C2C12) derived exosomes (Exosome-MS) on the Glucocorticoid-induced osteoporosis(GIOP) compared with unmechanically stimulated myocytes (C2C12) derived exosomes (Exosomes), we established a dexamethasone-induced osteoporosis model in vivo and in vitro. Cell viability and proliferation were assessed using CCK8 and EDU assays. Osteogenic potential was evaluated through Western blotting, real-time PCR, alkaline phosphatase activity assay, and alizarin red staining. Differential expression of miRNAs was determined by high-throughput sequencing. The regulatory mechanism of miR-92a-3p on cell proliferation and osteogenic differentiation via the PTEN/AKT pathway was investigated using real-time PCR, luciferase reporter gene assay, Western blotting, and immunofluorescence. The therapeutic effects of exosomes were evaluated in vivo using microCT, HE staining, Masson staining, and immunohistochemistry.

Results

 In this study, we found that exosomes derived from mechanical stress had a positive impact on the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs). Importantly, we demonstrated that miR-92a-3p mimics could reverse dexamethasone-induced osteoporosis in vitro and in vivo, indicating that mechanical stress-induced mouse myoblast-derived exosomes could promote osteogenesis and prevent the occurrence and progression of osteoporosis in mice through miR-92a-3p/PTEN/AKT signaling pathway.

Conclusion

 Exosomes derived from mechanical stress-induced myoblasts can promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells through miR-92a-3p/PTEN/AKT signaling pathway, and can have a therapeutic effect on glucocorticoid-induced osteoporosis in mice in vivo.

Dependency of B-Cell Acute Lymphoblastic Leukemia and Multiple Myeloma Cell Lines on MEN1 Extends beyond MEN1-KMT2A Interaction

Menin/MEN1 is a scaffold protein that participates in proliferation, regulation of gene transcription, DNA damage repair, and signal transduction. In hematological malignancies harboring the KMT2A/MLL1 (MLLr) chromosomal rearrangements, the interaction of the oncogenic fusion protein MLLr with MEN1 has been shown to be essential. MEN1 binders inhibiting the MEN1 and KMT2A interaction have been shown to be effective against MLLr AML and B-ALL in experimental models and clinical studies. We hypothesized that in addition to the MEN1-KMT2A interaction, alternative mechanisms might be instrumental in the MEN1 dependency of leukemia. We first mined and analyzed data from publicly available gene expression databases, finding that the dependency of B-ALL cell lines on MEN1 did not correlate with the presence of MLLr. Using shRNA-mediated knockdown, we found that all tested B-ALL cell lines were sensitive to MEN1 depletion, independent of the underlying driver mutations. Most multiple myeloma cell lines that did not harbor MLLr were also sensitive to the genetic depletion of MEN1. We conclude that the oncogenic role of MEN1 is not limited to the interaction with KMT2A. Our results suggest that targeted degradation of MEN1 or the development of binders that induce global changes in the MEN1 protein structure may be more efficient than the inhibition of individual MEN1 protein interactions.

A Trojan Horse Delivery Vehicle Carrying siRNA Nanotherapeutics with Multiple Tumor Microenvironment Responsiveness Elicits Robust Antitumor Immune Responses In Situ via a "Self-Synergistic" Approach

The potential of small interfering RNAs (siRNAs) in the treatment of malignant tumors has attracted increasing attention due to their inherent advantages. However, their therapeutic performance strongly depends on the efficiency of their cytoplasmic delivery in vivo by the delivery vehicle with good cellular permeability and histocompatibility. Herein, a polycationic carrier camouflaged with macrophage membrane (MPM) is constructed biomimetically, which is condensed from endogenous spermine monomers through diselenide bonds. The developed Trojan horse delivery vehicle has desirable compression efficacy for siRNA oligo against PD-L1 (siPDL1) as well as intracytoplasmic release properties derived from its sequential degradation triggered by redox microenvironment in tumor cells. Furthermore, the coloading of photosensitizer can mediate photodynamic therapy (PDT) accompanied by the generation of reactive oxygen species (ROS) upon light irradiation applied, which accelerated the degradation of the carrier as well as the release of cargoes while enhancing the PD-L1 blockage-mediated immunotherapy by inducing in-situ immunogenic cell death. Moreover, the synchronously delivered siPDL1 attenuated the ROS-induced increase in immunosuppressive PD-L1 expression, thereby effectively eliciting a robust antitumor immune response with a "self-synergistic" manner in the xenograft breast cancer mouse model.

Hyperglycemia-regulated tRNA-derived fragment tRF-3001a propels neurovascular dysfunction in diabetic mice

Neurovascular dysfunction is a preclinical manifestation of diabetic complications, including diabetic retinopathy (DR). Herein, we report that a transfer RNA-derived RNA fragment, tRF-3001a, is significantly upregulated under diabetic conditions. tRF-3001a downregulation inhibits Müller cell activation, suppresses endothelial angiogenic effects, and protects against high-glucose-induced retinal ganglion cell injury in vitro. Furthermore, tRF-3001a downregulation alleviates retinal vascular dysfunction, inhibits retinal reactive gliosis, facilitates retinal ganglion cell survival, and preserves visual function and visually guided behaviors in STZ-induced diabetic mice and db/db diabetic mice. Mechanistically, tRF-3001a regulates neurovascular dysfunction in a microRNA-like mechanism by targeting GSK3B. Clinically, tRF-3001a is upregulated in aqueous humor (AH) samples of DR patients. tRF-3001a downregulation inhibits DR-induced human retinal vascular endothelial cell and Müller cell dysfunction in vitro and DR-induced retinal neurovascular dysfunction in C57BL/6J mice. Thus, targeting tRF-3001a-mediated signaling is a promising strategy for the concurrent treatment of vasculopathy and neuropathy in diabetes mellitus.

DNAi-peptide nanohybrid smart particles target BCL-2 oncogene and induce apoptosis in breast cancer cells

Genomic DNA sequences provide unique target sites, with high druggability value, for treatment of genetically-linked diseases like cancer. B-cell lymphoma protein-2 (BCL-2) prevents Bcl-2-associated X protein (BAX) and Bcl-2 antagonist killer 1 (BAK) oligomerization, which would otherwise lead to the release of several apoptogenic molecules from the mitochondrion. It is also known that BCL-2 binds to and inactivates BAX and other pro-apoptotic proteins, thereby inhibiting apoptosis. BCL-2 protein family, through its role in regulation of apoptotic pathways, is possibly related to chemo-resistance in almost half of all cancer types including breast cancer. Here for the first time, we have developed a nanohybrid using a peptide-based carrier and a Deoxyribonucleic acid inhibitor (DNAi) against BCL-2 oncogene to induce apoptosis in breast cancer cells. The genetically designed nanocarrier was functionalized with an internalizing RGD (iRGD) targeting motif and successfully produced by recombinant DNA technology. Gel retardation assay demonstrated that the peptide-based carrier binds single-stranded DNAi upon simple mixing. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses further revealed the formation of nanohybrid particles with a size of 30 nm and a slightly positive charge. This hemocompatible nanohybrid efficiently delivered its contents into cancer cells using iRGD targeting moiety. Gene expression analysis demonstrated that the nanohybrids, which contained DNAi against BCL-2 proficiently suppressed the expression of this oncogene in a sequence specific manner. In addition, the nanohybrid, triggered release of cytochrome c (cyt c) and caspase3/7 activation with high efficiency. Although the DNAi and free nanocarrier were separately unable to affect the cell viability, the nanohybrid of 20 nM of DNAi showed outstanding antineoplastic potential, which was adjusted by the ratio of the MiRGD nanocarrier to DNAi. It should be noted that, the designed nanohybrid showed a suitable specificity profile and did not affect the viability of normal cells. The results suggest that this nanohybrid may be useful for robust breast cancer treatment through targeting the BCL-2 oncogene without any side effects.

MicroRNA-based therapeutics for inflammatory disorders of the microbiota-gut-brain axis

An emerging but less explored shared pathophysiology across microbiota-gut-brain axis disorders is aberrant miRNA expression, which may represent novel therapeutic targets. miRNAs are small, endogenous non-coding RNAs that are important transcriptional repressors of gene expression. Most importantly, they regulate the integrity of the intestinal epithelial and blood-brain barriers and serve as an important communication channel between the gut microbiome and the host. A well-defined understanding of the mode of action, therapeutic strategies and delivery mechanisms of miRNAs is pivotal in translating the clinical applications of miRNA-based therapeutics. Accumulating evidence links disorders of the microbiota-gut-brain axis with a compromised gut-blood-brain-barrier, causing gut contents such as immune cells and microbiota to enter the bloodstream leading to low-grade systemic inflammation. This has the potential to affect all organs, including the brain, causing central inflammation and the development of neurodegenerative and neuropsychiatric diseases. In this review, we have examined in detail miRNA biogenesis, strategies for therapeutic application, delivery mechanisms, as well as their pathophysiology and clinical applications in inflammatory gut-brain disorders. The research data in this review was drawn from the following databases: PubMed, Google Scholar, and Clinicaltrials.gov. With increasing evidence of the pathophysiological importance for miRNAs in microbiota-gut-brain axis disorders, therapeutic targeting of cross-regulated miRNAs in these disorders displays potentially transformative and translational potential. Further preclinical research and human clinical trials are required to further advance this area of research.

Targeting miRNA by CRISPR/Cas in cancer: advantages and challenges

Clustered regulatory interspaced short palindromic repeats (CRISPR) has changed biomedical research and provided entirely new models to analyze every aspect of biomedical sciences during the last decade. In the study of cancer, the CRISPR/CRISPR-associated protein (Cas) system opens new avenues into issues that were once unknown in our knowledge of the noncoding genome, tumor heterogeneity, and precision medicines. CRISPR/Cas-based gene-editing technology now allows for the precise and permanent targeting of mutations and provides an opportunity to target small non-coding RNAs such as microRNAs (miRNAs). However, the development of effective and safe cancer gene editing therapy is highly dependent on proper design to be innocuous to normal cells and prevent introducing other abnormalities. This study aims to highlight the cutting-edge approaches in cancer-gene editing therapy based on the CRISPR/Cas technology to target miRNAs in cancer therapy. Furthermore, we highlight the potential challenges in CRISPR/Cas-mediated miRNA gene editing and offer advanced strategies to overcome them.

MicroRNAs-Based Theranostics against Anesthetic-Induced Neurotoxicity

Various clinical reports indicate prolonged exposure to general anesthetic-induced neurotoxicity (in vitro and in vivo). Behavior changes (memory and cognition) are compilations commonly cited with general anesthetics. The ability of miRNAs to modulate gene expression, thereby selectively altering cellular functions, remains one of the emerging techniques in the recent decade. Importantly, engineered miRNAs (which are of the two categories, i.e., agomir and antagomir) to an extent found to mitigate neurotoxicity. Utilizing pre-designed synthetic miRNA oligos would be an ideal analeptic approach for intervention based on indicative parameters. This review demonstrates engineered miRNA's potential as prophylactics and/or therapeutics minimizing the general anesthetics-induced neurotoxicity. Furthermore, we share our thoughts regarding the current challenges and feasibility of using miRNAs as therapeutic agents to counteract the adverse neurological effects. Moreover, we discuss the scientific status and updates on the novel neuro-miRNAs related to therapy against neurotoxicity induced by amyloid beta (Aβ) and Parkinson's disease (PD).

Smart Nanocarriers for the Targeted Delivery of Therapeutic Nucleic Acid for Cancer Immunotherapy

A wide variety of therapeutic approaches and technologies for delivering therapeutic agents have been investigated for treating cancer. Recently, immunotherapy has achieved success in cancer treatment. Successful clinical results of immunotherapeutic approaches for cancer treatment were led by antibodies targeting immune checkpoints, and many have advanced through clinical trials and obtained FDA approval. A major opportunity remains for the development of nucleic acid technology for cancer immunotherapy in the form of cancer vaccines, adoptive T-cell therapies, and gene regulation. However, these therapeutic approaches face many challenges related to their delivery to target cells, including their in vivo decay, the limited uptake by target cells, the requirements for nuclear penetration (in some cases), and the damage caused to healthy cells. These barriers can be avoided and resolved by utilizing advanced smart nanocarriers (e.g., lipids, polymers, spherical nucleic acids, metallic nanoparticles) that enable the efficient and selective delivery of nucleic acids to the target cells and/or tissues. Here, we review studies that have developed nanoparticle-mediated cancer immunotherapy as a technology for cancer patients. Moreover, we also investigate the crosstalk between the function of nucleic acid therapeutics in cancer immunotherapy, and we discuss how nanoparticles can be functionalized and designed to target the delivery and thus improve the efficacy, toxicity, and stability of these therapeutics.

EPAS1 resistance to miRNA-based regulation contributes to prolonged expression of HIF-2 during hypoxia in human endothelial cells

The cellular adaptation to hypoxia is regulated by hypoxia inducible factors: HIF-1 and HIF-2. HIF-1 mediates response to acute hypoxia, whereas HIF-2 allows adaptation to chronic oxygen deprivation. The hypoxic transition from HIF-1 to HIF-2 is possible due to the low stability of HIF-1α subunit transcript (HIF1A) and the stable mRNA of HIF-2α (EPAS1). Notably, although many micro-RNAs (miRNAs) that regulate endothelial HIF-1 levels during hypoxia have been identified, in case of HIF-2, no analogous ones have been found so far. In this work, using different methods, we tested 23 microRNA that were predicted to interact with the EPAS1 transcript (18 of which were induced during prolonged hypoxia), and we demonstrated that none of them were functional in vitro. This suggests that HIF-2α transcript is much less prone to miRNA-related destabilization during hypoxia.

Tailoring biomimetic dual-redox-responsive nanoplexes for enhanced RNAi-synergized photodynamic cancer immunotherapy

Despite the strong potential of RNA interference (RNAi) therapies, critical issues, such as poor permeability across biological membranes and efficacy of their delivery into the cytoplasm, remain to be addressed before their successful clinical application. The current study aimed to address these issues by constructing a biomimetic nanoplex with dual redox responsiveness, which is derived from a cationic polymer formed by the condensation of endogenous spermine monomers via diselenide bonds. The developed nanoplexes decomposed in response to the redox microenvironment in cancer cells, thereby avoiding accumulation toxicity and poor transfection efficiency owing to incomplete siRNA release. When co-delivered with siPDL1 and a photosensitizer, the reactive oxygen species generated by irradiated nanoplexes accelerated the cytoplasmic release of siPDL1, which was expected to alleviate the PDT-induced increase in immunosuppressive PD-L1 expression. In a murine model of 4T1 xenografted breast cancer, the fabricated macrophage membrane (MPM)-camouflaged nanoplexes with payloads boosted antitumor immune responses in situ through a "self-synergistic" immunogenic cell death induced by photodynamic therapy (PDT). Overall, the study reported a new strategy for harnessing photodynamic immunotherapy for treating immunologically cold tumors. STATEMENT OF SIGNIFICANCE: This study provides a biomimetic nanoplex with dual redox responsiveness, which is derived from a novel cationic polymer formed by the condensation of endogenous spermine monomers through diselenide bonds. The developed nanoplex disassembles according to the redox microenvironment in cancer cells, thereby avoiding accumulation toxicity and poor transfection efficiency due to incomplete siRNA release. When co-delivery of siPDL1 and photosensitizer in vivo, the ROS generated by irradiated nanoplexes accelerated the cytoplasmic release of siPDL1, and which is expected to alleviate PDT-induced increase in immunosuppressive PD-L1 expression, thereby boosting antitumor immune responses in situ through a "self-synergistic" immunogenic cell death induced by PDT. Our findings reveal a new strategy of harnessing photodynamic immunotherapy therapy toward immunologically cold tumors.

AML1-ETO-Related Fusion Circular RNAs Contribute to the Proliferation of Leukemia Cells

The AML1-ETO (RUNX1-RUNX1T1) fusion gene created by the chromosome translocation t(8;21) (q21;q22) is one of the essential contributors to leukemogenesis. Only a few studies in the literature have focused on fusion gene-derived circular RNAs (f-circRNAs). Here, we report several AML1-ETO-related fusion circular RNAs (F-CircAEs) in AML1-ETO-positive cell lines and primary patient blasts. Functional studies demonstrate that the over-expression of F-CircAE in NIH3T3 cells promotes cell proliferation in vitro and in vivo. F-CircAE expression enhances the colony formation ability of c-Kit⁺ hematopoietic stem and progenitor cells (HSPCs). Meanwhile, the knockdown of endogenous F-CircAEs can inhibit the proliferation and colony formation ability of AML1-ETO-positive Kasumi-1 cells. Intriguingly, bioinformatic analysis revealed that the glycolysis pathway is down-regulated in F-CircAE-knockdown Kasumi-1 cells and up-regulated in F-CircAE over-expressed NIH3T3 cells. Further studies show that F-CircAE binds to the glycolytic protein ENO-1, up-regulates the expression level of glycolytic enzymes, and enhances lactate production. In summary, our study demonstrates that F-CircAE may exert biological activities on the growth of AML1-ETO leukemia cells by regulating the glycolysis pathway. Determining the role of F-CircAEs in AML1-ETO leukemia can lead to great strides in understanding its pathogenesis, thus providing new diagnostic markers and therapeutic targets.

MicroRNA-21 guide and passenger strand regulation of adenylosuccinate lyase-mediated purine metabolism promotes transition to an EGFR-TKI-tolerant persister state

In EGFR-mutant lung cancer, drug-tolerant persister cells (DTPCs) show prolonged survival when receiving EGFR tyrosine kinase inhibitor (TKI) treatments. They are a likely source of drug resistance, but little is known about how these cells tolerate drugs. Ribonucleic acids (RNAs) molecules control cell growth and stress responses. Nucleic acid metabolism provides metabolites, such as purines, supporting RNA synthesis and downstream functions. Recently, noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), have received attention due to their capacity to repress gene expression via inhibitory binding to downstream messenger RNAs (mRNAs). Here, our study links miRNA expression to purine metabolism and drug tolerance. MiR-21-5p (guide strand) is a commonly upregulated miRNA in disease states, including cancer and drug resistance. However, the expression and function of miR-21-3p (passenger strand) are not well understood. We found that upregulation of miR-21-5p and miR-21-3p tune purine metabolism leading to increased drug tolerance. Metabolomics data demonstrated that purine metabolism was the top pathway in the DTPCs compared with the parental cells. The changes in purine metabolites in the DTPCs were partially rescued by targeting miR-21. Analysis of protein levels in the DTPCs showed that reduced expression of adenylosuccinate lyase (ADSL) was reversed after the miR-21 knockdown. ADSL is an essential enzyme in the de novo purine biosynthesis pathway by converting succino-5-aminoimidazole-4-carboxamide riboside (succino-AICAR or SAICAR) to AICAR (or acadesine) as well as adenylosuccinate to adenosine monophosphate (AMP). In the DTPCs, miR-21-5p and miR-21-3p repress ADSL expression. The levels of top decreased metabolite in the DTPCs, AICAR was reversed when miR-21 was blocked. AICAR induced oxidative stress, evidenced by increased reactive oxygen species (ROS) and reduced expression of nuclear factor erythroid-2-related factor 2 (NRF2). Concurrently, miR-21 knockdown induced ROS generation. Therapeutically, a combination of AICAR and osimertinib increased ROS levels and decreased osimertinib-induced NRF2 expression. In a MIR21 knockout mouse model, MIR21 loss-of-function led to increased purine metabolites but reduced ROS scavenging capacity in lung tissues in physiological conditions. Our data has established a link between ncRNAs, purine metabolism, and the redox imbalance pathway. This discovery will increase knowledge of the complexity of the regulatory RNA network and potentially enable novel therapeutic options for drug-resistant patients.

Nanoparticles design considerations to co-deliver nucleic acids and anti-cancer drugs for chemoresistance reversal

Chemoresistance and hence the consequent treatment failure is considerably challenging in clinical cancer therapeutics. The understanding of the genetic variations in chemoresistance acquisition encouraged the use of gene modulatory approaches to restore anti-cancer drug efficacy. Many smart nanoparticles are designed and optimized to mediate combinational therapy between nucleic acid and anti-cancer drugs. This review aims to define a rational design of such co-loaded nanocarriers with the aim of chemoresistance reversal at various cellular levels to improve the therapeutic outcome of anticancer treatment. Going through the principles of therapeutics loading, physicochemical characteristics tuning, and different nanocarrier modifications, also looking at combination effectiveness on chemosensitivity restoration. Up to now, these emerging nanocarriers are in development status but are expected to introduce outstanding outcomes.

Delivery of Therapeutic miR-148b Mimic via Poly(β Amino Ester) Polyplexes for Post-transcriptional Gene Regulation and Apoptosis of A549 Cells

In this study, we utilized selectively modified, biodegradable polymer-based polyplexes to deliver custom, exogenous miR-148b mimics to induce apoptosis in human lung cancer (A549) cells. The gene regulatory effects of the payload miRNA mimics (miR-148b-3p) were first evaluated through bioinformatic analyses to uncover specific gene targets involved in critical carcinogenic pathways. Hyperbranched poly(β amino ester) polyplexes (hPBAE) loaded with custom miR-148b mimics were then developed for targeted therapy. When evaluated in vitro, these hPBAE-based polyplexes sustained high intracellular uptake, low cytotoxicity, and efficient escape from endosomes to deliver functionally intact miRNA mimics to the cytosol. High-resolution confocal microscopy revealed successful intracellular uptake, cell viability was assessed through qualitative fluorescence microscopy and fluorescence-based DNA quantification, and successful cytosolic delivery of intact miRNA mimics was evaluated using real-time polymerase chain reaction (RT-PCR) to demonstrate target gene knockdown. The hPBAE-miRNA mimic polyplexes were shown to induce apoptosis among A549 cells through direct modulation of intracellular protein expression, targeting multiple potential carcinogenic pathways at the gene level. These results indicated that spatially controlled miR-148b mimic delivery can promote efficient cancer cell death in vitro and may lead to an enhanced therapeutic design for in vivo application.

Targeting circRNA-MAP4K2 for the treatment of diabetes-induced retinal vascular dysfunction

Diabetic retinopathy (DR) is an important ocular vascular disease in working-age adults. However, the molecular mechanism underlying retinal vascular dysfunction is still not fully understood in DR. Circular RNAs have been recognized as the crucial regulators in many biological processes and human diseases. Herein, we determined the role of circular RNA-MAP4K2 (cMAP4K2) in diabetes-induced retinal vascular dysfunction. The results showed that high glucose treatment led to increased levels of cMAP4K2 expression in vitro and in vivo. Silencing of cMAP4K2 could reduce endothelial cell viability, proliferation, migration, and tube formation in vitro and alleviate retinal vascular dysfunction in vivo as shown by decreased vascular leakage and inflammation. By contrast, cMAP4K2 overexpression had an opposite effect on retinal vascular dysfunction. Mechanistically, cMAP4K2 acted as miR-377 sponge to affect the biological activity of miR-377, which led to increased expression of vascular endothelial growth factor A (VEGFA). Clinically, cMAP4K2 expression was significantly up-regulated in the clinical sample of DR patients. Collectively, cMAP4K2 is shown as a potential target for the diagnosis and treatment of diabetic retinopathy.

The miR-23-27-24 cluster: an emerging target in NAFLD pathogenesis

The incidence of non-alcoholic fatty liver disease (NAFLD) is increasing globally, being the most widespread form of chronic liver disease in the west. NAFLD includes a variety of disease states, the mildest being non-alcoholic fatty liver that gradually progresses to non-alcoholic steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. Small non-coding single-stranded microRNAs (miRNAs) regulate gene expression at the miRNA or translational level. Numerous miRNAs have been shown to promote NAFLD pathogenesis and progression through increasing lipid accumulation, oxidative stress, mitochondrial damage, and inflammation. The miR-23-27-24 clusters, composed of miR-23a-27a-24-2 and miR-23b-27b-24-1, have been implicated in various biological processes as well as many diseases. Herein, we review the current knowledge on miR-27, miR-24, and miR-23 in NAFLD pathogenesis and discuss their potential significance in NAFLD diagnosis and therapy.

Chitosan based nanoformulation expressing miR-155 as a promising adjuvant to enhance Th1-biased immune responses

BACKGROUND AND AIM

MiR-155 could act as a key modulator of different aspects of immune system including Th1 responses. In this study, we designed chitosan nanoparticles containing miR-155-expressing plasmid and explored their effects as an adjuvant to enhance Th1 responses for potential future application against intracellular pathogens.

METHODS

Nanoparticles were formulated by complex coacervation method and characterized for physicochemical and functional characteristics. Transfection efficiency in Raw 264.7 cells, effects on miR-155 target genes and NO production were evaluated. The prepared nanoparticles were co-administered as an adjuvant with ovalbumin to immunize mice and finally production of IFN-γ and IL-4 were measured by ELISA in splenocyte recall responses.

RESULTS

The prepared nanoparticles had the mean size of 244 nm and zeta potential of +17 mV, respectively. Electrophoresis analysis indicated the high capability of nanoparticles to protect the plasmid from DNaseI degradation. Furthermore, nanoparticles showed an appropriate transfection efficiency in Raw 264.7 cells and could downregulate the expression of miR-155 target genes and also upregulate NO production. In vivo immunization examinations revealed successful shift of T cell responses toward Th1.

CONCLUSION

Our data suggests the high potential of chitosan nanoparticles containing miR-155-expressing plasmid as an adjuvant for significantly enhanced Th1-biased immune responses upon immunization with a given antigen.

Bioactive coatings with anti-osteoclast therapeutic agents for bone implants: Enhanced compliance and prolonged implant life

The use of therapeutic agents that inhibit bone resorption is crucial to prolong implant life, delay revision surgery, and reduce the burden on the healthcare system. These therapeutic agents include bisphosphonates, various nucleic acids, statins, proteins, and protein complexes. Their use in systemic treatment has several drawbacks, such as side effects and insufficient efficacy in terms of concentration, which can be eliminated by local treatment. This review focuses on the incorporation of osteoclast inhibitors (antiresorptive agents) into bioactive coatings for bone implants. The ability of bioactive coatings as systems for local delivery of antiresorptive agents to achieve optimal loading of the bioactive coating and its release is described in detail. Various parameters such as the suitable concentrations, release times, and the effects of the antiresorptive agents on nearby cells or bone tissue are discussed. However, further research is needed to support the optimization of the implant, as this will enable subsequent personalized design of the coating in terms of the design and selection of the coating material, the choice of an antiresorptive agent and its amount in the coating. In addition, therapeutic agents that have not yet been incorporated into bioactive coatings but appear promising are also mentioned. From this work, it can be concluded that therapeutic agents contribute to the biocompatibility of the bioactive coating by enhancing its beneficial properties.

MicroRNA as an Important Target for Anticancer Drug Development

Cancer has become the second greatest cause of death worldwide. Although there are several different classes of anticancer drugs that are available in clinic, some tough issues like side-effects and low efficacy still need to dissolve. Therefore, there remains an urgent need to discover and develop more effective anticancer drugs. MicroRNAs (miRNAs) are a class of small endogenous non-coding RNAs that regulate gene expression by inhibiting mRNA translation or reducing the stability of mRNA. An abnormal miRNA expression profile was found to exist widely in cancer cell, which induces limitless replicative potential and evading apoptosis. MiRNAs function as oncogenes (oncomiRs) or tumor suppressors during tumor development and progression. It was shown that regulation of specific miRNA alterations using miRNA mimics or antagomirs can normalize the gene regulatory network and signaling pathways, and reverse the phenotypes in cancer cells. The miRNA hence provides an attractive target for anticancer drug development. In this review, we will summarize the latest publications on the role of miRNA in anticancer therapeutics and briefly describe the relationship between abnormal miRNAs and tumorigenesis. The potential of miRNA-based therapeutics for anticancer treatment has been critically discussed. And the current strategies in designing miRNA targeting therapeutics are described in detail. Finally, the current challenges and future perspectives of miRNA-based therapy are conferred.

Learning epistatic gene interactions from perturbation screens

The treatment of complex diseases often relies on combinatorial therapy, a strategy where drugs are used to target multiple genes simultaneously. Promising candidate genes for combinatorial perturbation often constitute epistatic genes, i.e., genes which contribute to a phenotype in a non-linear fashion. Experimental identification of the full landscape of genetic interactions by perturbing all gene combinations is prohibitive due to the exponential growth of testable hypotheses. Here we present a model for the inference of pairwise epistatic, including synthetic lethal, gene interactions from siRNA-based perturbation screens. The model exploits the combinatorial nature of siRNA-based screens resulting from the high numbers of sequence-dependent off-target effects, where each siRNA apart from its intended target knocks down hundreds of additional genes. We show that conditional and marginal epistasis can be estimated as interaction coefficients of regression models on perturbation data. We compare two methods, namely glinternet and xyz, for selecting non-zero effects in high dimensions as components of the model, and make recommendations for the appropriate use of each. For data simulated from real RNAi screening libraries, we show that glinternet successfully identifies epistatic gene pairs with high accuracy across a wide range of relevant parameters for the signal-to-noise ratio of observed phenotypes, the effect size of epistasis and the number of observations per double knockdown. xyz is also able to identify interactions from lower dimensional data sets (fewer genes), but is less accurate for many dimensions. Higher accuracy of glinternet, however, comes at the cost of longer running time compared to xyz. The general model is widely applicable and allows mining the wealth of publicly available RNAi screening data for the estimation of epistatic interactions between genes. As a proof of concept, we apply the model to search for interactions, and potential targets for treatment, among previously published sets of siRNA perturbation screens on various pathogens. The identified interactions include both known epistatic interactions as well as novel findings.

Targeting the De Novo Purine Synthesis Pathway Through Adenylosuccinate Lyase Depletion Impairs Liver Cancer Growth by Perturbing Mitochondrial Function

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is among the most common cancer types worldwide, yet patients with HCC have limited treatment options. There is an urgent need to identify drug targets that specifically inhibit the growth of HCC cells.

APPROACH AND RESULTS

We used a CRISPR library targeting ~2,000 druggable genes to perform a high-throughput screen and identified adenylosuccinate lyase (ADSL), a key enzyme involved in the de novo purine synthesis pathway, as a potential drug target for HCC. ADSL has been implicated as a potential oncogenic driver in some cancers, but its role in liver cancer progression remains unknown. CRISPR-mediated knockout of ADSL impaired colony formation of liver cancer cells by affecting AMP production. In the absence of ADSL, the growth of liver tumors is retarded in vivo. Mechanistically, we found that ADSL knockout caused S-phase cell cycle arrest not by inducing DNA damage but by impairing mitochondrial function. Using data from patients with HCC, we also revealed that high ADSL expression occurs during tumorigenesis and is linked to poor survival rate.

CONCLUSIONS

Our findings uncover the role of ADSL-mediated de novo purine synthesis in fueling mitochondrial ATP production to promote liver cancer cell growth. Targeting ADSL may be a therapeutic approach for patients with HCC.

Targeting circular RNAs as a therapeutic approach: current strategies and challenges

Significant progress has been made in circular RNA (circRNA) research in recent years. Increasing evidence suggests that circRNAs play important roles in many cellular processes, and their dysregulation is implicated in the pathogenesis of various diseases. CircRNAs are highly stable and usually expressed in a tissue- or cell type-specific manner. Therefore, they are currently being explored as potential therapeutic targets. Gain-of-function and loss-of-function approaches are typically performed using circRNA expression plasmids and RNA interference-based strategies, respectively. These strategies have limitations that can be mitigated using nanoparticle and exosome delivery systems. Furthermore, recent developments show that the cre-lox system can be used to knockdown circRNAs in a cell-specific manner. While still in the early stages of development, the CRISPR/Cas13 system has shown promise in knocking down circRNAs with high specificity and efficiency. In this review, we describe circRNA properties and functions and highlight their significance in disease. We summarize strategies that can be used to overexpress or knockdown circRNAs as a therapeutic approach. Lastly, we discuss major challenges and propose future directions for the development of circRNA-based therapeutics.

MicroRNA-155: Regulation of Immune Cells in Sepsis

MicroRNAs are small noncoding RNAs which regulate gene expression at the posttranscriptional level. miR-155 is encoded by the miR-155 host gene (miR155HG), also known as the noncoding B cell integration cluster (BIC). MicroRNAs are widely expressed in various hematopoietic cells and are involved in regulating the immune system. In this review, we summarized how miR-155 modulates specific immune cells and the regulatory role of miR-155 in sepsis. miR-155 is expressed by different populations of innate and adaptive immune cells and is involved in the regulation of development, proliferation, and function in these cells. Sepsis is associated with uncontrollable inflammatory responses, accompanied by unacceptably high mortality. Due to the inadequacy of diagnostic markers as well as treatment strategies, treating sepsis can be a huge challenge. So far, a large number of experiments have shown that the expression of miR-155 is increased at an early stage of sepsis and that this increase is positively correlated with disease progression and severity. In addition, by blocking the proinflammatory effects of miR-155, it can effectively improve sepsis-related organ injury, providing novel insights to identify potential biomarkers and therapeutic targets for sepsis. However, since most of the current research is limited to animal experiments, further clinical research is required to determine the function of miR-155 and its mechanism related to sepsis.

Mesenchymal stem cell (MSC)-derived exosomes as a cell-free therapy for patients Infected with COVID-19: Real opportunities and range of promises

There are no commercially available effective antiviral medications or vaccines to deal with novel coronavirus disease (COVID-19). Hence there is a substantial unmet medical need for new and efficacious treatment options for COVID-19. Most COVID-19 deaths result from acute respiratory distress syndrome (ARDS). This virus induces excessive and aberrant inflammation so it is important to control the inflammation as soon as possible. To date, results of numerous studies have been shown that mesenchymal stem cells and their derivatives can suppress inflammation. Exosomes function as intercellular communication vehicles to transfer bioactive molecules (based on their origins), between cells. In this review, the recent exosome-based clinical trials for the treatment of COVID-19 are presented. Potential therapy may include the following items: First, using mesenchymal stem cells secretome. Second, incorporating specific miRNAs and mRNAs into exosomes and last, using exosomes as carriers to deliver drugs.

RNA therapeutics for retinal diseases

INTRODUCTION

In the retina, noncoding RNA (ncRNA) plays an integral role in regulating apoptosis, inflammatory responses, visual perception, and photo-transduction, with altered levels reported in diseased states.

AREAS COVERED

MicroRNA (miRNA), a class of ncRNA, regulates post-transcription gene expression through the binding of complementary sites of target messenger RNA (mRNA) with resulting translational repression. Small-interfering RNA (siRNA) is a double-stranded RNA (dsRNA) that regulates gene expression, leading to selective silencing of genes through a process called RNA interference (RNAi). Another form of RNAi involves short hairpin RNA (shRNA). In age-related macular degeneration (AMD) and diabetic retinopathy (DR), miRNA has been implicated in the regulation of angiogenesis, oxidative stress, immune response, and inflammation.

EXPERT OPINION

Many RNA-based therapies in development are conveniently administered intravitreally, with the potential for pan-retinal effect. The majority of these RNA therapeutics are synthetic ncRNA's and hold promise for the treatment of AMD, DR, and inherited retinal diseases (IRDs). These RNA-based therapies include siRNA therapy with its high specificity, shRNA to 'knock down' autosomal dominant toxic gain of function-mutated genes, antisense oligonucleotides (ASOs), which can restore splicing defects, and translational read-through inducing drugs (TRIDs) to increase expression of full-length protein from genes with premature stop codons.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial-mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Regulators at Every Step—How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Emerging Prospects of Exosomes for Cancer Treatment: From Conventional Therapy to Immunotherapy

Exosomes are a class of extracellular vesicles of around 100 nm in diameter that are secreted by most cells and contain various bioactive molecules reflecting their cellular origin and mediate intercellular communication. Studies of these exosomal features in tumor pathogenesis have led to the development of therapeutic and diagnostic approaches using exosomes for cancer therapy. Exosomes have many advantages for conveying therapeutic agents such as small interfering RNAs, microRNAs, membrane-associated proteins, and chemotherapeutic compounds; thus, they are considered a prime candidate as a delivery tool for cancer treatment. Since exosomes also provide an optimal microenvironment for the effective function of immunomodulatory factors, exosomes harboring bioactive molecules have been bioengineered as cancer immunotherapies that can effectively activate each stage of the cancer immunity cycle to successfully elicit cancer-specific immunity. This review discusses the advantages of exosomes for treating cancer and the challenges that must be overcome for their successful clinical development.