Three 'E' challenges for siRNA drug development

Chitosan nanovectors for siRNA delivery: New horizons for nonviral gene therapy

The growing interest in RNA-based therapeutics has positioned small interfering RNA (siRNA) as a promising tool for gene silencing with high specificity and efficacy. However, the successful clinical application of siRNA therapies requires efficient delivery systems to overcome extracellular and intracellular barriers. Chitosan, a naturally derived polysaccharide, has gained significant attention as a non-viral vector due to its biodegradability, biocompatibility, mucoadhesive properties, and capacity to enhance cellular uptake. These attributes make chitosan an attractive alternative to lipid-based nanoparticles, which currently dominate siRNA delivery platforms. Recent advancements in chitosan-based nanoformulations, including chemical modifications and functionalization strategies, have improved siRNA stability, targeting efficiency, and transfection potential, addressing key limitations such as low bioavailability and immunogenicity. Despite these advances, challenges remain in achieving optimal release kinetics, scalability, and consistent therapeutic efficacy. Future research efforts will focus on engineering chitosan derivatives with enhanced physicochemical properties, integrating multifunctional nanocarriers, and refining formulation strategies to bridge the gap between preclinical research and clinical translation. The continued development of chitosan-based siRNA therapeutics holds significant potential for advancing precision medicine and expanding treatment options for a variety of diseases, including cancer, metabolic disorders, and inflammatory conditions.

Targeted delivery systems of siRNA based on ionizable lipid nanoparticles and cationic polymer vectors

As an emerging therapeutic tool, small interfering RNA (siRNA) had the capability to down-regulate nearly all human mRNAs via sequence-specific gene silencing. Numerous studies have demonstrated the substantial potential of siRNA in the treatment of broad classes of diseases. With the discovery and development of various delivery systems and chemical modifications, six siRNA-based drugs have been approved by 2024. The utilization of siRNA-based therapeutics has significantly propelled efforts to combat a wide array of previously incurable diseases and advanced at a rapid pace, particularly with the help of potent targeted delivery systems. Despite encountering several extracellular and intracellular challenges, the efficiency of siRNA delivery has been gradually enhanced. Currently, targeted strategies aimed at improving potency and reducing toxicity played a crucial role in the druggability of siRNA. This review focused on recent advancements on ionizable lipid nanoparticles (LNPs) and cationic polymer (CP) vectors applied for targeted siRNA delivery. Based on various types of targeted modifications, we primarily described delivery systems modified with receptor ligands, peptides, antibodies, aptamers and amino acids. Finally, we discussed the challenges and opportunities associated with siRNA delivery systems based on ionizable LNPs and CPs vectors.

The role of micro-ribonucleic acid and small interfering-ribonucleic acid in precision nutrition for obesity management

BACKGROUND & AIMS

Precision nutrition aims to tailor dietary interventions based on genetic and molecular profiles. MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are emerging as critical tools in precision obesity management. miRNAs serve as biomarkers for predicting dietary response and obesity risk, while siRNAs provide a targeted approach to silencing obesity-related genes. This review explores the mechanisms, applications, and potential of integrating miRNA and siRNA in personalized dietary strategies to combat obesity.

METHODS

A comprehensive literature review was conducted using Boolean operations to identify studies on miRNAs, siRNAs, and their roles in precision nutrition. The review focused on molecular mechanisms, clinical applications, challenges, and future directions in integrating miRNA detection and siRNA therapy for obesity management.

RESULTS

miRNAs regulate gene expression related to lipid metabolism, adipogenesis, and insulin sensitivity, with miRNA-33 and miRNA-103/107 being notable examples. siRNAs offer precise gene silencing for targets like SREBP-1c and PPARγ, addressing metabolic pathways resistant to dietary interventions. The synergistic integration of miRNAs as biomarkers and siRNAs as therapeutic tools enhances the personalization and efficacy of obesity management.

CONCLUSIONS

The dual application of miRNAs and siRNAs in precision nutrition represents a transformative approach to obesity management. While challenges such as molecular stability and delivery systems persist, advancements in RNA technology and clinical research promise to revolutionize personalized dietary strategies. Future research should focus on large-scale trials and ethical considerations to ensure equitable and effective implementation.

MUC1 as a diagnostic biomarker and siRNA-based therapeutic target in breast cancer: A clinical chemistry perspective

Breast cancer remains the leading cause of cancer mortality in women, and early detection coupled with real-time monitoring of tumor burden are clinical imperatives; yet existing imaging-based screening (e.g., mammography, ultrasound) suffers from sensitivities as low as 60-80% and even lower in dense breasts plus substantial false-positive rates, underscoring the critical need for molecular assays with higher accuracy. Current clinical assays for circulating MUC1 (CA15-3) achieve high specificity but exhibit limited sensitivity in early-stage disease, underscoring a critical unmet need for more sensitive, multiplexed biomarkers to enable timely intervention. Mass spectrometry-based glycoproteomic workflows offer multiplexed quantification of tumour-associated MUC1 glycoforms, substantially improving analytical specificity and dynamic range. Complementary liquid-biopsy platforms that detect anti-MUC1 autoantibodies further extend lead time for recurrence detection. Concurrently, small interfering RNA (siRNA) therapies targeting MUC1 delivered via ionizable lipid nanoparticles demonstrate efficient tumor accumulation, robust mRNA knockdown, and favourable safety in phaseI solid tumor trials. In this review, we critically assess the analytical performance and standardization challenges of current MUC1 assays, evaluate emerging mass spectrometry and immunoarray techniques, and examine chemical and nanocarrier strategies that surmount biological barriers to siRNA delivery. We propose a co-development framework for harmonized companion diagnostics and MUC1-directed RNAi therapeutics under unified regulatory pathways, paving the way for precision, biomarker-driven interventions in breast cancer care.

Structural optimization of phthalazine derivatives for anti-HBV activities to improve oral bioavailability

The hepatitis B virus (HBV) capsid protein forms a protective nucleocapsid essential for viral replication, establishing capsid assembly modulation as a promising therapeutic strategy. Based on previous mechanistic studies, we identified phthalazine derivatives as potent HBV capsid assembly modulators (CAMs), with Yhhu6517 exhibiting submicromolar antiviral activity in vitro. However, its clinical translation was hindered by poor oral pharmacokinetics (PK), due to rapid first-pass metabolism of oxidation-prone primary alcohol groups. Through metabolic stability-guided structure-activity relationship (SAR) studies involving systematic replacement of primary alcohols with non-primary alcohol-derived hydrophilic groups, we optimized the fragments to yield compound 2p. This optimized candidate 2p maintained a potent anti-HBV activity (IC50 = 0.016 μM in HepG2.2.15 cells) while demonstrating improved an oral bioavailability (F = 80.6 % in mice) and enhanced plasma exposure (AUC0-24h = 10.3 μg·h/mL). These findings confirm phthalazine-based anti-HBV agents, with compound 2p emerging as a candidate for the further development.

Delivery of siGPX4 through a thiol-mediated pathway using a fluorinated cell-penetrating poly(disulfide) for inducing ferroptosis in breast cancer

Cell-penetrating poly(disulfides) (CPDs) are promising siRNA delivery vectors, utilizing thiol-mediated uptake to avoid lysosomal retention. However, like other cationic vectors, CPDs require excess positive charge for vector/siRNA complexes stability, risking cytotoxicity. Additionally, serum protein adsorption can disrupt complexes, diminishing transfection efficiency. In this study, we designed a series of fluorinated CPDs (FX-CPD-n) to enhance siRNA delivery efficiency through the specific fluorophilic effect. Fluorination introduces unique hydrophobic and lipophobic characteristics, promoting phase separation in polar and non-polar environments. In vitro results demonstrated that moderate fluorination improved siRNA binding, cellular uptake, and transfection efficiency of the CPD-based vectors, while excessive fluorination hindered siRNA binding and increased cytotoxicity. Moreover, fluorination slightly altered the uptake mechanism, with most uptake still occurring via the thiol-mediated pathway. Importantly, fluorination enhanced serum tolerance capacity, maintaining effective cellular uptake and gene silencing capacity in serum-rich conditions. Subsequently, an optimized vector, FL-CPDs-30, effectively delivered siPGX4 (siRNA targeting glutathione peroxidase 4) to breast cancer cells, silencing GPX4 at both the protein and mRNA levels. FL-CPDs-30/siGPX4 exhibited significant anticancer activity in vitro and in vivo by inducing ferroptosis. These effects were attributed to efficient GPX4 silencing and GSH depletion via the disulfide backbone of CPDs. This work provides valuable insights into the development of thiol-mediated siRNA delivery vectors and offers a promising platform for siRNA-based ferroptosis induction in cancer therapy. STATEMENT OF SIGNIFICANCE: Efficient cytosolic delivery remains a major challenge in siRNA-based therapeutics. In this study, we demonstrated that fluorinated cell-penetrating poly(disulfide)s (CPDs), with optimal fluorine density, enhanced siRNA binding, cellular uptake, and transfection efficiency compared to unmodified CPDs. Fluorination also improved the serum tolerance capacity of CPDs. Moreover, the fluorinated CPDs predominantly entered cancer cells via a thiol-mediated pathway. The leading fluorinated CPD significantly outperformed both native CPDs and conventional transfection agents in silencing siPGX4 (glutathione peroxidase 4) and inducing ferroptosis in vitro and in vivo. In addition to efficient GPX4 knockdown, GSH depletion through the CPD disulfide backbone further potentiated ferroptosis in breast cancer. This strategy presents a promising approach for advancing siRNA-based gene therapy.

Intracellular Nanodelivery of DNA with Enzyme-Degradable and pH-Responsive Peptide Dendrons

Effective DNA delivery requires functional materials to package and transport genetic cargo into cells. However, many synthetic systems rely on heterogeneous mixtures, lack biodegradability, and pose toxicity concerns. Here, we introduce a peptide dendron single-molecule transfection reagent that enables targeted DNA delivery via pH-responsive, degradable nanoparticles with minimal toxicity. Peptide dendrons for intracellular delivery (PDIDs) incorporate ionizable non-natural amino acids for DNA binding and pH sensitivity. PDIDs formed stable nanoparticles that released DNA upon lysosomal acidification, facilitating cytoplasmic entry and subsequent gene expression. Rationally designed triamino acid blocks promoted protease degradation, reducing toxicity in preclinical models. Targeting ligands further enhanced the transfection efficiency by increasing cell uptake. In a lung metastasis model, targeted PDID-DNA nanoparticles selectively delivered therapeutic gene cargo to the lung, reducing tumor burden and extending survival. This platform demonstrates the potential to integrate natural and non-natural peptide features to enable safe and efficient DNA delivery in vivo.

ncRNAs as Key Regulators in Gastric Cancer: From Molecular Subtyping to Therapeutic Targets

Gastric cancer (GC) poses a major global health challenge, underscoring the need for advanced diagnostic and therapeutic approaches. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have emerged as pivotal regulators in GC, with their dysregulated expression driving key processes such as tumorigenesis, metastasis, immune evasion, and chemoresistance. The functional diversity of ncRNAs across different GC molecular subtypes highlights their potential as biomarkers for improved subtype classification and patient stratification. Beyond their diagnostic value, ncRNAs demonstrate critical regulatory functions in tumor biology, establishing these RNA molecules as promising targets for therapeutic development. Strategies based on RNA hold considerable promise for addressing critical challenges such as immune escape and drug resistance by modulating key signaling pathways. These approaches can enhance immune responses, reprogram the tumor microenvironment, and reverse resistance mechanisms that compromise treatment efficacy, thereby improving clinical outcomes. Although ncRNAs represent a promising frontier in GC precision medicine, further research is required to fully harness their clinical potential.

Nanotechnology-Enhanced siRNA Delivery: Revolutionizing Cancer Therapy

RNA interference (RNAi) has emerged as a transformative approach for cancer therapy, enabling precise gene silencing through small interfering RNA (siRNA). However, the clinical application of siRNA-based treatments faces challenges such as rapid degradation, inefficient cellular uptake, and immune system clearance. Nanotechnology-enhanced siRNA delivery has revolutionized cancer therapy by addressing these limitations, improving siRNA stability, tumor-specific targeting, and therapeutic efficacy. Recent advancements in nanocarrier engineering have introduced innovative strategies to enhance the safety and precision of siRNA-based therapies, offering new opportunities for personalized medicine. This review highlights three key innovations in nanotechnology-enhanced siRNA delivery: artificial intelligence (AI)-driven nanocarrier design, multifunctional nanoparticles for combined therapeutic strategies, and biomimetic nanocarriers for enhanced biocompatibility. AI-driven nanocarriers utilize machine learning algorithms to optimize nanoparticle properties, improving drug release profiles and minimizing off-target effects. Multifunctional nanoparticles integrate siRNA with chemotherapy, immunotherapy, or photothermal therapy, enabling synergistic treatment approaches that enhance therapeutic outcomes and reduce drug resistance. Biomimetic nanocarriers, including exosome-mimicking systems and cell-membrane-coated nanoparticles, improve circulation time, immune evasion, and targeted tumor delivery. These innovations collectively enhance the precision, efficiency, and safety of siRNA-based cancer therapies. The scope and novelty of these advancements lie in their ability to overcome the primary barriers of siRNA delivery while paving the way for clinically viable solutions. This review provides a comprehensive analysis of the latest developments in nanocarrier fabrication, preclinical and clinical studies, and safety assessments. By integrating AI-driven design, multifunctionality, and biomimicry, nanotechnology-enhanced siRNA delivery holds immense potential for the future of precision cancer therapy.

Dendrimer nanocarriers for targeted co-delivery of MiR-146b-3p and 5-ALA to synergistic photodynamic therapy in secondary hyperparathyroidism

The combination of photodynamic therapy (PDT) and gene therapy is a viable therapeutic approach for the management of secondary hyperparathyroidism (SHPT). Nevertheless, the effective delivery of photosensitizers or nucleotide drugs remains a crucial limitation in achieving therapeutic efficacy. MiR-146b-3p directly targeted BCL2, and its overexpression enhanced the antiproliferative, proautophagic, and proapoptotic effects during 5-aminolevulinic acid (5-ALA)-mediated PDT in this study. Herein, we investigated the potential of codelivering 5-ALA and miR-146b-3p to SHPT primary cells via polyamidoamine (PAMAM) and achieving enhanced therapeutic efficacy relative to that of monotreatment. The fabrication of the PAMAM-based 5-ALA and miR-146b-3p dual-delivery system (5-ALA@PAMAM/miR) involved the use of covalent condensation reactions and electrostatic self-assembly. The nanoparticles were characterized by various analytical techniques, including transmission electron microscopy (TEM), zeta potential measurements, and size measurements. Fluorescence and confocal laser scanning microscopy demonstrated a greater degree of cellular uptake of nanoparticles. Moreover, the synthesized nanoparticles considerably enhanced the effectiveness of PDT without systemic toxicity both in vitro and in vivo. Overall, the nanocarrier-gene-photosensitizer coloaded system is a promising platform for the efficient simultaneous delivery of miR-146b-3p and 5-ALA and achieves synergistic therapeutic effects.

Application of small interfering RNA technology in cytochrome P450 gene modulation

Cytochrome P450 plays key roles in the biotransformation of endogenous and exogenous chemicals including drugs and environmental pollutants. The inhibition and downregulation of P450s can have therapeutic effects, and/or modulate drug metabolism. P450s are largely inhibited by small molecules; however, this strategy is often hampered by intrinsic toxicity and drug-drug interactions. Furthermore, it is challenging for small molecules to exhibit high selectivity and inhibitory efficiencies. Recently, small interfering RNA (siRNA) technology has demonstrated the potential for P450 modulation. Examples of recent applications of siRNAs in P450 gene modulation, in vitro and in vivo, are highlighted in this review. The necessity of siRNA techniques and their advantages as P450 modulators are discussed, along with a review of current obstacles and a perspective on future advancements. SIGNIFICANCE STATEMENT: This article reviews studies on the application of small interfering RNA technology to cytochrome P450 gene modulation. The necessity of siRNA methods and the benefits of their use as P450 modulators have been suggested by comparison with small-molecule drugs. Additionally, the challenges that presently limit the broader implementation of this topic are examined, and a perspective for future developments is proposed.

Polymer-siRNA nanovectors for treating lung inflammation

Uncontrolled inflammation is the driver of numerous lung diseases. Current treatments, including corticosteroids and bronchodilators, can be effective. However, they often come with notable side effects. siRNA is a promising therapeutic modality for immune regulation. However, effective delivery of siRNA is challenged by issues related to cellular uptake and localization within tissues. This study investigates a series of guanidinium-functionalized polymers (Cn-Guan) designed to explore the effects of amphiphilicity on siRNA complexation and efficiency in vitro and in vivo. Nine polymers with varying side chain lengths (C3, C5, C7) and molecular weights (17 kDa, 30 kDa, 65 kDa) were synthesized, forming polyplexes with siRNA. Characterization revealed that C7-Guan/si_scr polymers exhibited the smallest polyplex sizes and the tightest complexation with siRNA. In vitro studies showed that 65 kDa polymers had the highest gene knockdown efficiency, with C3 and C5-Guan/si_TNF-α achieving ∼70 % knockdown, while C7-Guan/si_TNF-α achieved ∼30 %. In vivo, C7-Guan/Cy5-siRNA demonstrated the highest lung accumulation, and all polymers showed ∼70 % TNF-α knockdown with a low siRNA dosage (0.14 mg/kg) in a murine lung inflammation model. C7-Guan polymers, despite lower in vitro efficiency, were quite effective in vivo, potentially due to enhanced serum stability. These findings demonstrate that Cn-Guan/siRNA polyplexes are effective and safe for attenuating pulmonary inflammation and provide important insights for the development of future siRNA delivery vectors for lung disease treatment.

Delivery of small interfering RNA by hydrogen sulfide-releasing nanomotor for the treatment of Parkinson's disease

Small interfering RNA (siRNA) that inhibit the formation of α-synuclein (α-syn) aggregates is considered very promising therapeutic agents for the treatment of Parkinson's disease (PD). However, the low stability and the difficulty in crossing the blood-brain barrier (BBB) of free siRNA has severely limited their therapeutic effects. Here, we developed an H2S donor nanomotor that can encapsulate siRNA, which can both protect the activity of siRNA and help siRNA to be effectively targeted to the mitochondria of damaged neuronal cells, in order to promote the effective therapeutic effect of siRNA for PD. Specifically, the cysteine monomer-modified polyethylene glycol (PEG-Cys) and the amphiphilic ionic monomer 2-methacryloyloxyethylphosphorylcholine (MPC) that can effectively penetrate the BBB, were selected to form a polymer protective layer on the surface of siRNA in a free-radical polymerization reaction, to construct the H2S donor nanomotor encapsulating siRNA (PCM@siRNA). Among them, MPC can help PCM@siRNA to break through the BBB by interacting with nicotinic acetylcholine receptor or choline transporter on the surface of cerebrovascular endothelial cells, while PEG-Cys can undergo chemotactic effect by specifically recognizing 3-thiopyruvate thioltransferase and thus achieve effective targeting of damaged mitochondria in neuronal cells. PCM@siRNA that reached neuronal cells can not only be utilized to play the role of silencing the α-syn gene to inhibit the formation of α-syn aggregates by siRNA, but also to degrade the formed α-syn aggregates by using the H2S produced by its chemotaxis process to achieve an effective treatment for PD. This therapeutic modality, which can simultaneously inhibit the formation of α-syn aggregates and promote their degradation, has the therapeutic potential to reverse the pathological state of α-syn, which is important for the treatment of PD.

An anti-RAGE chimeric antibody alleviates CCl4-induced liver fibrosis via RAGE/NF-kB pathway in mice

Liver fibrosis is a progressive condition characterized by excessive deposition of extracellular matrix components, leading to organ dysfunction. Chronic inflammation and activation of hepatic stellate cells (HSCs) are two dominant events in all stages of fibrosis development. The receptor for advanced glycation end products (RAGE) pathway is involved in modulating liver injury and fibrosis, and preventing it, or deletion of Ager gene can protect the liver against fibrosis progression. To investigate functions and mechanism of chimeric anti-RAGE monoclonal antibody against liver fibrosis, murine-derived monoclonal anti-RAGE antibodies were used to construct murine-human chimeric antibodies. The properties of the chimeric antibody were characterized, and the biological functions of antibody A5 or its evolved humanized molecule, huA5, were investigated in cell or animal model. The data showed that blocking the RAGE pathway with huA5 robustly reduced liver injury and fibrosis. Furthermore, huA5 significantly suppressed the activation of HSCs and inhibited expression of fibrosis-associated genes, including COL1A1,TIMP1, and ACTA2. huA5 also interfered with RAGE downstream signal transduction and down-regulate both ERK and NF-κB phosphorylation, inhibited the RAGE/NF-kB pathway, leading to reduced expression of pro-inflammatory cytokines and profibrotic markers. Finally, RAGE silencing significantly decreased the expression of activation-related genes in HSCs, inhibiting HSCs proliferation and migration. These results clearly revealed that the anti-RAGE chimeric antibody exerted antifibrotic efficacy in vitro and attenuated liver fibrosis in vivo. HuA5 can be further developed as a lead molecule of drug to treat patients with liver fibrosis.

Functions and applications of RNA interference and small regulatory RNAs

Small regulatory RNAs play a variety of crucial roles in eukaryotes, influencing gene regulation, developmental timing, antiviral defense, and genome integrity via a process termed RNA interference (RNAi). This process involves Argonaute/small RNA (AGO/sRNA) complexes that target transcripts via sequence complementarity and modulate gene expression and epigenetic modifications. RNAi is a highly conserved gene regulatory phenomenon that recognizes self- and non-self nucleic acids, thereby defending against invasive sequences. Since its discovery, RNAi has been widely applied in functional genomic studies and a range of practical applications. In this review, we focus on the current understanding of the biological roles of the RNAi pathway in transposon silencing, fertility, developmental regulation, immunity, stress responses, and acquired transgenerational inheritance. Additionally, we provide an overview of the applications of RNAi technology in biomedical research, agriculture, and therapeutics.

Nanotechnological approaches for efficient N2B delivery: from small-molecule drugs to biopharmaceuticals

Central nervous system diseases negatively affect patients and society. Providing successful noninvasive treatments for these diseases is challenging because of the presence of the blood-brain barrier. While protecting the brain's homeostasis, the barrier limits the passage of almost all large-molecule drugs and most small-molecule drugs. A noninvasive method, nose-to-brain delivery (N2B delivery) has been proposed to overcome this challenge. By exploiting the direct anatomical interaction between the nose and the brain, the drugs can reach the target, the brain. Moreover, the drugs can be encapsulated into various drug delivery systems to enhance physicochemical characteristics and targeting success. Many preclinical data show that this strategy can effectively deliver biopharmaceuticals to the brain. Therefore, this review focuses on N2B delivery while giving examples of different drug delivery systems suitable for the applications. In addition, we emphasize the importance of the effective delivery of monoclonal antibodies and RNA and stress the recent literature tackling this challenge. While giving examples of nanotechnological approaches for the effective delivery of small or large molecules from the current literature, we highlight the preclinical studies and their results to prove the strategies' success and limitations.

Circular RNAs in programmed cell death: Regulation mechanisms and potential clinical applications in cancer: A review

Circular RNAs (circRNAs) are a novel class of non-coding RNAs with covalently closed structures formed by reverse splicing of precursor mRNAs. The widespread expression of circRNAs across species has been revealed by high-throughput sequencing and bioinformatics approaches, indicating their unique properties and diverse functions including acting as microRNA sponges and interacting with RNA-binding proteins. Programmed cell death (PCD), encompassing various forms such as apoptosis, necroptosis, pyroptosis, autophagy, and ferroptosis, is an essential process for maintaining normal development and homeostasis in the human body by eliminating damaged, infected, and aging cells. Many studies have demonstrated that circRNAs play crucial roles in tumourigenesis and development by regulating PCD in tumor cells, showing that circRNAs have the potential to be biomarkers and therapeutic targets in cancer. This review aims to comprehensively summarize the intricate associations between circRNAs and diverse PCD pathways in tumor cells, which play crucial roles in cancer development. Additionally, this review provides a detailed overview of the underlying mechanisms by which circRNAs modulate various forms of PCD for the first time. The ultimate objective is to offer valuable insights into the potential clinical significance of developing novel strategies based on circRNAs and PCD for cancer diagnosis, prognosis, and treatment.

Decoding Cancer through Silencing the Mitochondrial Gatekeeper VDAC1

Mitochondria serve as central hubs for regulating numerous cellular processes that include metabolism, apoptosis, cell cycle progression, proliferation, differentiation, epigenetics, immune signaling, and aging. The voltage-dependent anion channel 1 (VDAC1) functions as a crucial mitochondrial gatekeeper, controlling the flow of ions, such as Ca2+, nucleotides, and metabolites across the outer mitochondrial membrane, and is also integral to mitochondria-mediated apoptosis. VDAC1 functions in regulating ATP production, Ca2+ homeostasis, and apoptosis, which are essential for maintaining mitochondrial function and overall cellular health. Most cancer cells undergo metabolic reprogramming, often referred to as the "Warburg effect", supplying tumors with energy and precursors for the biosynthesis of nucleic acids, phospholipids, fatty acids, cholesterol, and porphyrins. Given its multifunctional nature and overexpression in many cancers, VDAC1 presents an attractive target for therapeutic intervention. Our research has demonstrated that silencing VDAC1 expression using specific siRNA in various tumor types leads to a metabolic rewiring of the malignant cancer phenotype. This results in a reversal of oncogenic properties that include reduced tumor growth, invasiveness, stemness, epithelial-mesenchymal transition. Additionally, VDAC1 depletion alters the tumor microenvironment by reducing angiogenesis and modifying the expression of extracellular matrix- and structure-related genes, such as collagens and glycoproteins. Furthermore, VDAC1 depletion affects several epigenetic-related enzymes and substrates, including the acetylation-related enzymes SIRT1, SIRT6, and HDAC2, which in turn modify the acetylation and methylation profiles of histone 3 and histone 4. These epigenetic changes can explain the altered expression levels of approximately 4000 genes that are associated with reversing cancer cells oncogenic properties. Given VDAC1's critical role in regulating metabolic and energy processes, targeting it offers a promising strategy for anti-cancer therapy. We also highlight the role of VDAC1 expression in various disease pathologies, including cardiovascular, neurodegenerative, and viral and bacterial infections, as explored through siRNA targeting VDAC1. Thus, this review underscores the potential of targeting VDAC1 as a strategy for addressing high-energy-demand cancers. By thoroughly understanding VDAC1's diverse roles in metabolism, energy regulation, mitochondrial functions, and other cellular processes, silencing VDAC1 emerges as a novel and strategic approach to combat cancer.

Oligonucleotide Therapies for Facioscapulohumeral Muscular Dystrophy: Current Preclinical Landscape

Facioscapulohumeral muscular dystrophy (FSHD) is an inherited myopathy, characterized by progressive and asymmetric muscle atrophy, primarily affecting muscles of the face, shoulder girdle, and upper arms before affecting muscles of the lower extremities with age and greater disease severity. FSHD is a disabling condition, and patients may also present with various extramuscular symptoms. FSHD is caused by the aberrant expression of double homeobox 4 (DUX4) in skeletal muscle, arising from compromised epigenetic repression of the D4Z4 array. DUX4 encodes the DUX4 protein, a transcription factor that activates myotoxic gene programs to produce the FSHD pathology. Therefore, sequence-specific oligonucleotides aimed at reducing DUX4 levels in patients is a compelling therapeutic approach, and one that has received considerable research interest over the last decade. This review aims to describe the current preclinical landscape of oligonucleotide therapies for FSHD. This includes outlining the mechanism of action of each therapy and summarizing the preclinical results obtained regarding their efficacy in cellular and/or murine disease models. The scope of this review is limited to oligonucleotide-based therapies that inhibit the DUX4 gene, mRNA, or protein in a way that does not involve gene editing.

2'-O-Alkyl-N 3-Methyluridine Functionalized Passenger Strand Improves RNAi Activity by Modulating the Thermal Stability

Herein, we have demonstrated that the siRNA activity could be enhanced by incorporating the guide strand in the RISC complex through thermodynamic asymmetry caused by m3U-based destabilizing modifications. A nuclease stability study revealed that 2'-OMe-m3U and 2'-OEt-m3U modifications slightly improved the half-lives of siRNA strands in human serum. In the in vitro gene silencing assay, 2'-OMe-m3U modification at the 3'-overhang and cleavage site of the passenger strand in anti-renilla and anti-Bcl-2 siRNA duplexes were well-tolerated and exhibited improved gene silencing activity. However, gene silencing activity was attenuated when these modifications were incorporated at position 3 in the seed region of the antisense strand. The molecular modeling studies using these modifications at the seed region with the MID domain of hAGO2 explained that the 2'-alkoxy group makes steric interactions with the amino acid residues of the hAGO2 protein.

Advances in structural-guided modifications of siRNA

To date, the US Food and Drug Administration (FDA) has approved six small interfering RNA (siRNA) drugs: patisiran, givosiran, lumasiran, inclisiran, vutrisiran, and nedosiran, serving as compelling evidence of the promising potential of RNA interference (RNAi) therapeutics. The successful implementation of siRNA therapeutics is improved through a combination of various chemical modifications and diverse delivery approaches. The utilization of chemically modified siRNA at specific sites on either the sense strand (SS) or antisense strand (AS) has the potential to enhance resistance to ribozyme degradation, improve stability and specificity, and prolong the efficacy of drugs. Herein, we provide comprehensive analyses concerning the correlation between chemical modifications and structure-guided siRNA design. Various modifications, such as 2'-modifications, 2',4'-dual modifications, non-canonical sugar modifications, and phosphonate mimics, are crucial for the activity of siRNA. We also emphasize the essential strategies for enhancing overhang stability, improving RISC loading efficacy and strand selection, reducing off-target effects, and discussing the future of targeted delivery.

Human antigen R: Exploring its inflammatory response impact and significance in cardiometabolic disorders

RNA-binding proteins (RBPs) play a crucial role in the regulation of posttranscriptional RNA networks, which can undergo dysregulation in many pathological conditions. Human antigen R (HuR) is a highly researched RBP that plays a crucial role as a posttranscriptional regulator. HuR plays a crucial role in the amplification of inflammatory signals by stabilizing the messenger RNA of diverse inflammatory mediators and key molecular players. The noteworthy correlations between HuR and its target molecules, coupled with the remarkable impacts reported on the pathogenesis and advancement of multiple diseases, position HuR as a promising candidate for therapeutic intervention in diverse inflammatory conditions. This review article examines the significance of HuR as a member of the RBP family, its regulatory mechanisms, and its implications in the pathophysiology of inflammation and cardiometabolic illnesses. Our objective is to illuminate potential directions for future research and drug development by conducting a comprehensive analysis of the existing body of research on HuR.

Hedgehog Pathway Inhibition by Novel Small Molecules Impairs Melanoma Cell Migration and Invasion under Hypoxia

Melanoma is the principal cause of death in skin cancer due to its ability to invade and cause metastasis. Hypoxia, which characterises the tumour microenvironment (TME), plays an important role in melanoma development, as cancer cells can adapt and acquire a more aggressive phenotype. Carbonic anhydrases (CA) activity, involved in pH regulation, is related to melanoma cell migration and invasion. Furthermore, the Hedgehog (Hh) pathway, already known for its role in physiological processes, is a pivotal character in cancer cell growth and can represent a promising pharmacological target. In this study, we targeted Hh pathway components with cyclopamine, glabrescione B and C22 in order to observe their effect on carbonic anhydrase XII (CAXII) expression especially under hypoxia. We then performed a migration and invasion assay on two melanoma cell lines (SK-MEL-28 and A375) where Smoothened, the upstream protein involved in Hh regulation, and GLI1, the main transcription factor that determines Hh pathway activation, were chemically inhibited. Data suggest the existence of a relationship between CAXII, hypoxia and the Hedgehog pathway demonstrating that the chemical inhibition of the Hh pathway and CAXII reduction resulted in melanoma migration and invasion impairment especially under hypoxia. As in recent years drug resistance to small molecules has arisen, the development of new chemical compounds is crucial. The multitarget Hh inhibitor C22 proved to be effective without signs of cytotoxicity and, for this reason, it can represent a promising compound for future studies, with the aim to reach a better melanoma disease management.

Isolectin B4 (IB4)-conjugated streptavidin for the selective knockdown of proteins in IB4-positive (+) nociceptors

In vivo analysis of protein function in nociceptor subpopulations using antisense oligonucleotides and short interfering RNAs is limited by their non-selective cellular uptake. To address the need for selective transfection methods, we covalently linked isolectin B4 (IB4) to streptavidin and analyzed whether it could be used to study protein function in IB4(+)-nociceptors. Rats treated intrathecally with IB4-conjugated streptavidin complexed with biotinylated antisense oligonucleotides for protein kinase C epsilon (PKCε) mRNA were found to have: a) less PKCε in dorsal root ganglia (DRG), b) reduced PKCε expression in IB4(+) but not IB4(-) DRG neurons, and c) fewer transcripts of the PKCε gene in the DRG. This knockdown in PKCε expression in IB4(+) DRG neurons is sufficient to reverse hyperalgesic priming, a rodent model of chronic pain that is dependent on PKCε in IB4(+)-nociceptors. These results establish that IB4-streptavidin can be used to study protein function in a defined subpopulation of nociceptive C-fiber afferents.

Isolectin B4 (IB4)-conjugated streptavidin for the selective knockdown of proteins in IB4-positive (+) nociceptors

In vivo analysis of protein function in nociceptor subpopulations using antisense oligonucleotides and short interfering RNAs is limited by their non-selective cellular uptake. To address the need for selective transfection methods, we covalently linked isolectin B4 (IB4) to streptavidin and analyzed whether it could be used to study protein function in IB4(+)-nociceptors. Rats treated intrathecally with IB4-conjugated streptavidin complexed with biotinylated antisense oligonucleotides for protein kinase C epsilon (PKCε) mRNA were found to have: (a) less PKCε in dorsal root ganglia (DRG), (b) reduced PKCε expression in IB4(+) but not IB4(-) DRG neurons, and (c) fewer transcripts of the PKCε gene in the DRG. This knockdown in PKCε expression in IB4(+) DRG neurons is sufficient to reverse hyperalgesic priming, a rodent model of chronic pain that is dependent on PKCε in IB4(+)-nociceptors. These results establish that IB4-streptavidin can be used to study protein function in a defined subpopulation of nociceptive C-fiber afferents.